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Sample records for gneiss terranes adjacent

  1. Zircon U-Pb ages of Guyana greenstone-gneiss terrane

    Energy Technology Data Exchange (ETDEWEB)

    Gibbs, A.K. (Cornell Univ., Ithaca, NY (USA)); Olszewski, W.J. Jr. (New Hampshire Univ., Durham (USA))

    1982-04-01

    Isotopic U-Pb studies of zircons collected from weathered metagreywackes of the Barama-Mazaruni Supergroup of northern Guyana, South America, demonstrate an age of origin of ca. 2250 Ma. This is the best estimate for the age of the associated metavolcanic rocks. Zircons from weathered gneiss of the Bartica complex, adjacent to the volcanic-sedimentary belts, yield a similar age. The contiguous greenstone-gneiss terrane of eastern Venezuela is also of similar age and comparable greenstone-gneiss terranes of eastern Suriname and French Guiana are probably also of this age. Continental crust formation of a style closely comparable to that of the Canadian Archean occurred on a very widespread scale in the Lower Proterozoic of the Guiana shield. The lead losses from the weathered zircons are comparable to those from zircons from fresh rock from the adjacent terrane of Venezuela, and the advantages of field concentration from numerous saprolite exposures warrant use of such material in future geochronological studies of the region.

  2. Geophysical interpretation of the gneiss terrane of northern Washington and southern British Columbia, and its implications for uranium exploration

    Science.gov (United States)

    Cady, John W.; Fox, Kenneth F.

    1984-01-01

    The Omineca crystalline belt of northeastern Washington and southern British Columbia has a regional Bouguer gravity high, and individual gneiss domes within the terrane are marked by local gravity highs. Models of crustal structure that satisfy the limited available seismic-refraction data and explain the gravity high over the gneiss terrane permit the hypothesis that the core metamorphic complexes are the surface expression of a zone of dense infrastructure that makes up the upper 20 km (kilometers) of the crust within the crystalline belt. The Omineca crystalline belt is characterized regionally by low aeromagnetic relief. The gneiss domes and biotite- and biotite-muscovite granites are generally marked by low magnetic relief, whereas hornblende-biotite granites often cause magnetic highs. Exceptional magnetic highs mark zones of magnetic rock within the biotite- and biotite-muscovite granites and the gneiss domes; these areas are worthy of study, both to determine the origin and disposition of the magnetite and to explore the possible existence of uraniferous magnetite deposits.

  3. Archean crustal evolution of the Narryer Gneiss Terrane, Western Australia, as revealed by the U-Pb age and Hf-isotope compositions of zircon from the granitic gneisses

    Science.gov (United States)

    Sylvester, P.; Souders, K.; Crowley, J. L.; Myers, J.

    2011-12-01

    The Narryer Gneiss Terrane of the Yilgarn Craton, Western Australia, is an important area for studies of early crustal evolution because of the preservation of (1) detrital zircons of Hadean to Archean age in the Jack Hills and Mt. Narryer metasedimentary belts, and (2) several widespread units of granitic gneisses emplaced between ca. 3.7 and 2.6 Ga. We have analyzed the U-Pb geochronology and Hf-isotope geochemistry of magmatic zircons from 38 samples of the granitic gneisses using laser ablation - (multicollector) - ICPMS. The sample suite is dominated by the Meeberrie gneiss, a banded quartz-microcline-oligoclase-biotite gneiss of monzogranite to granodiorite composition, and the Dugel gneiss, a leucocratic, pegmatite-layered syenogranite gneiss, but gneisses of dioritic to tonalitic composition, as well as less deformed granite sheets, are also represented. Magmatic zircons were identified on the basis of the preservation of oscillatory zoning in BSE and CL images, igneous Th/U ratios (>0.2), and concordant U-Pb isotopic systematics with low common Pb contents. The results indicate many of the gneisses are composed of the products of multiple magmatic events, as has been reported previously for samples of the Meeberrie gneiss (Kinny & Nutman, 1996, Precambrian Res. 78, 165-178). Major ages of magmatism preserved in the gneisses occurred at ca. 3685-3665 Ma, 3620-3565 Ma, 3495-3440 Ma, 3375-3330 Ma, and 3300-3260 Ma. The late granite sheets crystallized at 2710-2645 Ma. Hf-isotope compositions of the zircons trend to less radiogenic values with decreasing age, with ɛHf values of ca. 0 to -5 for 3.7-3.4 Ga gneisses, ca. -1 to -9 for 3.4-3.2 Ga gneisses and ca. -5 to -20 for the late granite sheets. The array of the Hf isotopic compositions with time for the entire sample set are fit well by a regression indicating a source reservoir with a 176Lu/177Hf of 0.022 extracted from the depleted mantle at 3.9 Ga. This suggests that the Narryer gneisses and late granite

  4. Evolution of the Archean continental crust in the nucleus of the Yangtze block: Evidence from geochemistry of 3.0 Ga TTG gneisses in the Kongling high-grade metamorphic terrane, South China

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    Qiu, Xiao-Fei; Ling, Wen-Li; Liu, Xiao-Ming; Lu, Shan-Song; Jiang, Tuo; Wei, Yun-Xu; Peng, Lian-Hong; Tan, Juan-Juan

    2018-04-01

    Archean Tonalite-Trondhjemite-Granodiorite (TTG) rocks are scattered within the Kongling high-grade metamorphic terrane (KHMT) in the northern South China block. A comprehensive geochronological and geochemical study is carried out on the Taoyuan granitic gneisses, a newly recognized TTG suite in the northwestern KHMT. This suite has long been regarded as a Mesoproterozoic magmatic pluton, but U-Pb zircon ages of 2994 ± 22 Ma and 2970 ± 15 Ma are obtained by LA-ICP-MS method in this study. The Taoyuan gneiss suite is trondhjemitic in composition, and has high SiO2 (67.80-74.93 wt.%), Na2O (5.11-5.81 wt.%) contents with Na2O/K2O ratios greater than unity, and low Ni (2.56-7.61 ppm), Cr (1.26-7.67 ppm), Yb (0.32-0.82 ppm) and Y (4.48-11.5 ppm) contents. Plots show large variation in La/Yb and Sr/Y ratios and pronounced depletion in Nb, Ta and Ti in the primitive mantle-normalized spiderdiagram. The gneiss suite also displays two-stage Nd model ages close to its crystallization age with corresponding εNd(t) values of -2.5 to +3.5. It is thus suggested that the Taoyuan gneisses, in fact, is part of the Archean Kongling basement complex. Geochemical evidence implies that the TTG rocks may be derived from partial melting of subducted oceanic crust from a garnetiferous amphibolite source with residual assemblage of garnet + amphibole + plagioclase. Our study further indicates that the nucleus of the Yangtze block might experience a juvenile continental crustal growth during Mesoarchean. We also suggest that the Yangtze block may have its own crustal evolutionary history independent from the North China craton and the Tarim block before Paleoproterozoic.

  5. Geology, geochemistry, and geochronology (U-Pb) of the Rio Fortuna Gneiss - Serra do Bau intrusive Suite - Paragua Terrane SW Amazonian Craton

    Energy Technology Data Exchange (ETDEWEB)

    Faria, Debora Almeida; Ruiz, Amarildo Salina; Matos, Joao Batista; Sousa, Maria Zelia Aguiar de; Lima, Gabrielle Aparecida de [Research Group on Crustal and Tectonic Evolution, Guapore, RS (Brazil); Universidade Federal de Mato Grosso (ICET/UFMT), Cuiaba, MT (Brazil). Instituto de Ciencias Exatas e da Terra; Inst. Nacional de Ciencia e Tecnologia de Geociencias da Amazonia (GEOCIAM), Belem, PA (Brazil); Moacir Jose Buenano Macambira, E-mail: defaal.debora@gmail.com, E-mail: gabilimagel@gmail.com, E-mail: asruiz@gmail.com, E-mail: jmatos@ufmt.br, E-mail: prof.mzaguiar@gmail.com, E-mail: moamac@ufpa.br [Research Group on Crustal and Tectonic Evolution, Guapore, RS (Brazil); Universidade Federal do Para (UFPA), Belem, PA (Brazil)

    2014-07-01

    The Rio Fortuna Gneiss crops out in the Serra Santa Barbara, near the Fortuna military headquarters, on the Brazil-Bolivia border. These orthogneisses are located in a portion of the Paragua terrain affected by the Sunsas Orogeny (1.0-0.9 Ga.). They are classified as monzo to granodiorite orthogneisses and underwent at least three episodes of deformation. The U-Pb zircon age of 1,711 ± 13 Ma obtained by laser ablation MC-ICP-MS is interpreted as the crystallization age of this orthogneiss. Geochemically, these rocks form a sequence comprising acidic subalkaline magmatism, calc-alkalic-type high-K, and metaluminous to peraluminous. (author)

  6. On the metamorphic history of an Archaean granitoid greenstone terrane, East Pilbara, Western Australia, using the 40Ar/39Ar age spectrum technique

    International Nuclear Information System (INIS)

    Wijbrans, J.R.; McDougall, I.

    1987-01-01

    Age spectrum analyses of blue-green hornblendes from amphibolites from the Western Shaw Belt, East Pilbara, Western Australia, indicate an age of at least 3200 Ma for early regional metamorphism. Ages on hornblende and muscovite from the narrow contact zone with the adjacent Yule Batholith probably data updoming of the granitoid gneiss terranes at 2950 Ma. Hornblendes from within the Shaw Batholith and from a contact zone of a post-tectonic granitoid yield ages of 2840-2900 Ma, indicating either prolonged high temperatures within the granitoid gneiss terranes or a separate thermal pulse associated with the intrusion of post-tectonic granitoids. The preservation of very old hornblendes in a narrow greenstone belt surrounded by massive granitoid gneiss domes indicates that remarkable contrasts in metamorphic geotherms existed over short distances during the Late Archaean, suggesting that updoming occurred during a period of rapid tectonism. (orig.)

  7. On the metamorphic history of an Archaean granitoid greenstone terrane, East Pilbara, Western Australia, using the /sup 40/Ar//sup 39/Ar age spectrum technique

    Energy Technology Data Exchange (ETDEWEB)

    Wijbrans, J.R.; McDougall, I.

    1987-07-01

    Age spectrum analyses of blue-green hornblendes from amphibolites from the Western Shaw Belt, East Pilbara, Western Australia, indicate an age of at least 3200 Ma for early regional metamorphism. Ages on hornblende and muscovite from the narrow contact zone with the adjacent Yule Batholith probably data updoming of the granitoid gneiss terranes at 2950 Ma. Hornblendes from within the Shaw Batholith and from a contact zone of a post-tectonic granitoid yield ages of 2840-2900 Ma, indicating either prolonged high temperatures within the granitoid gneiss terranes or a separate thermal pulse associated with the intrusion of post-tectonic granitoids. The preservation of very old hornblendes in a narrow greenstone belt surrounded by massive granitoid gneiss domes indicates that remarkable contrasts in metamorphic geotherms existed over short distances during the Late Archaean, suggesting that updoming occurred during a period of rapid tectonism.

  8. Gondwanan/peri-Gondwanan origin for the Uchee terrane, Alabama and georgia: Carolina zone or Suwannee terrane(?) and its suture with Grenvillian basement of the Pine Mountain window

    Science.gov (United States)

    Steltenpohl, M.G.; Mueller, P.M.; Heatherington, A.L.; Hanley, T.B.; Wooden, J.L.

    2008-01-01

    The poorly known, suspect, Uchee terrane occupies a critical tectonic position with regard to how and when peri-Gondwanan (Carolina) and Gondwanan (Suwannee) terranes were sutured to Laurentia. It lies sandwiched between Laurentian(?) continental basement exposed in the Pine Mountain window and adjacent buried Gondwanan crust of the Suwannee terrane. The Uchee terrane has been proposed as both a septum of Piedmont rocks that once was continuous across the erosionally breached Pine Mountain window or part of the Carolina zone. To help resolve this issue, we conducted U-Pb (SHRIMP-RG) (sensitive high-resolution ion microprobe-reverse geometry) zircon studies and whole-rock isotopic analyses of principal metasedimentary and metaplutonic units. U-Pb ages for zircons from the Phenix City Gneiss suggest igneous crystallization at ca. 620 Ma, inheritance ca. 1000 to ca. 1700 Ma, and a ca. 300 Ma (Alleghanian) overprint recorded by zircon rims. Zircons from the metasedimentary/metavolcaniclastic Moffits Mill Schist yield bimodal dates at ca. 620 and 640 Ma. The 620 to 640 Ma dates make these rocks age-equivalent to the oldest parts of the Carolina slate belt (Virgilina and Savannah River) and strongly suggest a Gondwanan (Pan-African and/or Trans-Brasiliano) origin for the Uchee terrane. Alternatively, the Uchee terrane may be correlative with metamorphic basement of the Suwannee terrane. The ca. 300 Ma overgrowths on zircons are compatible with previously reported 295 to 288 Ma 40Ar/39Ar hornblende dates on Uchee terrane rocks, which were interpreted to indicate deep tectonic burial of the Uchee terrane contemporaneous with the Alleghanian orogeny recorded in the foreland. Temperature-time paths for the Uchee terrane are similar to that of the Pine Mountain terrane, indicating a minimum age of ca. 295 Ma for docking. In terms of tectono-metamorphic history of the Uchee terrane, it is important to note that no evidence for intermediate "Appalachian" dates (e.g, Acadian or

  9. 40Ar/39Ar incremental-release ages of biotite from a progressively remetamorphosed Archean basement terrane in southwestern Labrador

    International Nuclear Information System (INIS)

    Dallmeyer, R.D.

    1982-01-01

    Gneisses within Archean basement terrane adjacent to the southwestern portion of the Labrador Trough were variably retrograded during a regional metamorphism of Grenville age (ca. 1000 Ma). Bioties from non-retrograded segments of the gneiss terrane record 40 Ar/ 39 Ar plateau and isochron ages which date times of cooling following an episode of the Kenoran orogeny (2376-2391 Ma). A suite of gneiss samples displaying varying degrees of retrograde alteration was collected across the Grenville metamorphic gradient. Bioties in these samples show no petrographic evidence of retrograde alteration, however they do record internally discordant 40 Ar/ 39 Ar age spectra. Although the extent of internal discordance is variable, the overall character of the release patterns is similar with younger apparent ages recorded in intermediate-temperature gas fractions. The total-gas dates range from 2257+-27 Ma (northwest) to 1751+-23 Ma (southeast), suggesting that variable quantities of radiogenic argon were lost from the Archean biotites during Grenville metamorphism. The 'saddle-shaped' nature of the discordant spectra indicates that argon loss was not accomplished through single-stage, volume diffusion processes. (orig./ME)

  10. Petrography and geochemistry of five granitic plutons from south central Uruguay: contribution to the knowledge of the Piedra Alta terrane

    International Nuclear Information System (INIS)

    Preciozzi, F.

    2005-01-01

    Granitoid rocks in south-central Uruguay are largely concentrated in three east-west trending metamorphic belts, known as (from south to north) the Montevideo Belt, the San José Belt and the Arroyo Grande Belt. These belts are separated from one another by intervening bands of gneisses of granitic composition. The whole assemblage, the gneisses as well as the metamorphic belts and their associated granites, collectively constitute the Piedra Alta Terrane. Five of these granite plutons, two from the San José Belt and three from the Arroyo Grande Belt, have been studied in some detail and the chemical composition of 86 samples (major elements as well as a selected suite of trace elements) have been determined. These data, as well as Rb-Sr isotopic data, show that these plutons are typically composite in nature, and that the various units range in age from 1900 Ma to 2500 Ma. The older ages were obtained from the main units of the plutons themselves whereas the younger ages are from late dykes which were emplaced into the plutons and which are clearly not related to them. The plutons are predominantly, but not exclusively, of calc-alkaline affinity and are typically synorogenic whereas the dykes are post-orogenic and are either calc-alkaline or alkaline in composition. These data have been incorporated into a tectonic model for the Piedra Alta Terrane which is considerably different from that heretofore proposed. The essential features of the geological history of the area are: 1) development of an older ''basement'' of granitic gneisses 2) deposition, upon or adjacent to this gneisses basement, of a typical Archean greenstone belt assemblage (no komatiites so far reported) 3) Paleo-proterozoic metamorphism, followed by syn-tectonic to post-tectonic intrusion of the plutonic rocks 4) major tectonic dislocation(s) associated with the Transamazonian orogeny 5) dyke emplacement (post-orogenic to anorogenic) following the Transamazonian orogeny

  11. Mafic rocks from Erinpura gneiss terrane in the Sirohi region ...

    Indian Academy of Sciences (India)

    1Department of Geology, University of Rajasthan, Jaipur 302 004, India. 2GeoZentrum .... from massive to foliated types wherein the gener- ally steep foliations show ... ered for kinematic analyses of the shear movement. These features are ...

  12. An exotic terrane in the Sulu UHP region, China

    Science.gov (United States)

    Chu, W.; Zhang, R.; Tsujimori, T.; Liou, J. G.

    2004-12-01

    The Haiyangsuo region of about 15 km2 along the coast in the NE part of the Triassic Sulu UHP terrane occurs three major rock types: amphibolitized metagabbro, gneiss and granitic dikes. Three different gneisses were observed in the field: A) Light color felsic gneiss is the dominant country rock and contains Qtz, Pl, Ms and Bi. B) Dark color plagioclase-amphibole gneiss occurs as thin layers within country rock; C) Granulite facies rock occurs as discontinuous lens. The amphibolitized metagabbros intrude into the gneisses as massive bodies (several m to hundreds of m in size) and thin dikes. Both metamorphic intrusives and gneisses are cross-cut by granitic dikes. The amphibolitized metagabbro was divided into three types: coronal metagabbro, transitional rock and garnet amphibolite: 1) Coronal metagabbro preserves gabbroic texture and primary assemblage of Opx+Cpx+Pl+Amp+Ilm. Most pyroxene grains are partially rimmed by thin corona of Amp+Ab+Qtz. Garnet occurs as fine-grained coronas at interface between plagioclase, pyroxene or ilmenite. 2) Transitional rocks contain similar assemblage and texture but most orthopyroxenes were partially or totally replaced by Amp+Qtz; garnet increases in content and size. Some gabbroic textures are preserved, but calcic plagioclase was replaced by zoisite, albite and muscovite. 3) Garnet amphibolite occurs at the margins of intrusive bodies and boudins where only minor relict clinopyroxenes preserve. Garnet coronal chains are not clear any more. Granitic dikes show pronounced deformation with mylonitic texture and contain 40-50% quartz porphyroclasts. Zircon separates from 2 metagabbros, 4 gneisses and 1 granitic rock were dated by using Stanford SHRIMP-RG. Metagabbroic zircons are angular and fractured shapes. The upper-intercept ages of gneisses rang from 1730 to about 2400 Ma, indicating variable protoith age. The 2 garnet amphibolites have upper-intercept ages 1734±5Ma and 1735±21Ma respectively. They are much older than

  13. Siberia, the wandering northern terrane, and its changing geography through the Palaeozoic

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    Cocks, L. Robin M.; Torsvik, Trond H.

    2007-05-01

    The old terrane of Siberia occupied a very substantial area in the centre of today's political Siberia and also adjacent areas of Mongolia, eastern Kazakhstan, and northwestern China. Siberia's location within the Early Neoproterozoic Rodinia Superterrane is contentious (since few if any reliable palaeomagnetic data exist between about 1.0 Ga and 540 Ma), but Siberia probably became independent during the breakup of Rodinia soon after 800 Ma and continued to be so until very near the end of the Palaeozoic, when it became an integral part of the Pangea Supercontinent. The boundaries of the cratonic core of the Siberian Terrane (including the Patom area) are briefly described, together with summaries of some of the geologically complex surrounding areas, and it is concluded that all of the Palaeozoic underlying the West Siberian Basin (including the Ob-Saisan Surgut area), Tomsk Terrane, Altai-Sayan Terranes (including Salair, Kuznetsk Alatau, Batenov, Kobdin and West Sayan), Ertix Terrane, Barguzin Terrane, Tuva-Mongol Terrane, Central Mongolia Terrane Assemblage, Gobi Altai and Mandalovoo Terranes, Okhotsk Terrane and much of the Verkhoyansk-Kolyma region all formed parts of peri-Siberia, and thus rotated with the main Siberian Craton as those areas were progressively accreted to the main Siberian Terrane at various times during the latest Neoproterozoic and Palaeozoic. The Ertix Terrane is a new term combining what has been termed the "Altay Terrane" or "NE Xinjiang" area of China, and the Baytag, Baaran and Bidz terranes of Mongolia. The Silurian Tuvaella brachiopod fauna is restricted only to today's southern parts of peri-Siberia. Thus, allowing for subsequent rotation, the fauna occurs only in the N of the Siberian Terrane, and, as well as being a helpful indicator of what marginal terranes made up peri-Siberia, is distinctive as being the only Silurian fauna known from northern higher latitudes globally. In contrast, the other terranes adjacent to peri

  14. U-Pb detrital zircon geochronology from the basement of the Central Qilian Terrane: implications for tectonic evolution of northeastern Tibetan Plateau

    Science.gov (United States)

    Liu, Changfeng; Wu, Chen; Zhou, Zhiguang; Yan, Zhu; Jiang, Tian; Song, Zhijie; Liu, Wencan; Yang, Xin; Zhang, Hongyuan

    2018-03-01

    The Tuolai Group dominates the Central Qilian Terrane, and there are different opinions on the age and tectonic attribute of the Tuolai Group. Based on large-scale geologic mapping and zircon dating, the Tuolai Group is divided into four parts: metamorphic supracrustal rocks, Neoproterozoic acid intrusive rocks, early-middle Ordovician acid intrusive rocks and middle Ordovician basic intrusive rocks. The metamorphic supracrustal rocks are the redefined Tuolai complex-group and include gneiss and schist assemblage by faulting contact. Zircon U-Pb LA-MC-ICP-MS dating was conducted on these samples of gneiss and migmatite from the gneiss assemblage, quartzite, two-mica schist and slate from the schist assemblage. The five detrital samples possess similar age spectra; have detrital zircon U-Pb main peak ages of 1.7 Ga with youngest U-Pb ages of 1150 Ma. They are intruded by Neoproterozoic acid intrusive rocks. Therefore, the Tuolai Group belonging to late Mesoproterozoic and early Neoproterozoic. With this caveat in mind, we believe that U-Pb detrital zircon dating, together with the geologic constraints obtained from this study and early work in the neighboring regions. We suggest that the formation age of the entire crystalline basement rocks of metasedimentary sequence from the Central Qilian Terrane should be constrained between the Late Mesoproterozoic and the Late Neoproterozoic, but not the previous Paleoproterozoic. The basement of the Central Qilian Terrane contains the typical Grenville ages, which indicates the Centre Qilian Terrane have been experienced the Grenville orogeny event.

  15. Geochronological investigation of the Ingerdal granite gneiss and discordant pegmatites from the western gneiss region, Norway

    International Nuclear Information System (INIS)

    Tucker, R.D.; Krogh, T.E.

    1988-01-01

    A seven-point (three zircon and four titanite ) U-Pb discordia-line from the Ingdal granite gneiss defines upper- and lover-intercept ages of 1653 ±2 Ma and 396 ±5 Ma interpreted as the time of Ingdal granite emplacement, and the time of gneiss formation and partial Pb-loss from zircon and titanite during a regional metamorphic event, respectively. These isotopic data suggest that this part of the western gneiss region was heated and cooled very quickly at both the upper- and lower-intercept ages, and that it did not experience significant Sveconorwegian (appr. 1250-900 Ma) or Finnmarkian (appr. 530-480 Ma) isotopic disturbance. A six-point Rb-Sr whole-rock errorchron (MSWD=11) from the same body of the Ingdal granite gneiss defines a date of 1665 ±49 Ma interpreted as a less precise age of granite emplacement. Rb-Sr mineral dates from three strongly discordant, non-foliated granite pegmatites fall in the age range of 415-379 Ma. A Rb-Sr biotite date of 372 ±4 Ma from the Ingdal granite gneiss establishes a minimum age of isotopic disturbance in the region

  16. Microstructural finite strain analysis and 40Ar/39Ar evidence for the origin of the Mizil gneiss dome, eastern Arabian Shield, Saudi Arabia

    Science.gov (United States)

    Al-Saleh, Ahmad M.; Kassem, Osama M. K.

    2012-07-01

    The Mizil antiform is a gneiss-cored culmination situated near the northern end of the Ar Rayn island arc terrane, which is the easternmost exposed tectonic unit of the Arabian Shield. This domal structure has a mantle of metamorphosed volcanosedimentary rocks belonging to the Al-Amar Group, and an igneous interior made up of foliated granodiorite-tonalite with adakitic affinity. The gneissic core has a SHRIMP U-Pb zircon age of 689 ± 10 Ma making it the oldest rock unit in the Ar Rayn terrane. An adakite diapir, formed by the melting of the subducted crust of a young marginal basin, and rising through the volcanosedimentary succession of the Ar Rayn island arc is thought to have caused the observed doming. Relatively uniform strain throughout the dome combined with strong vertical shortening and the roughly radial pattern of stretching lineation is consistent with diapirism; the absence of strain localization rules out detachment faulting as a causative mechanism. Amphibolites from the metamorphic envelope have an 40Ar/39Ar age of 615 ± 2 Ma; the age gap between core and cover is thought to reflect the resetting of metamorphic ages during the final suturing event, a phenomenon that is often observed throughout the eastern shield. Aeromagnetic anomalies beneath the Phanerozoic sedimentary cover indicate the presence of a collage of accreted terranes east of the Ar Rayn terrane that were probably amalgamated onto the Arabian margin during the latest stages of the closure of the Mozambique ocean; culminant orogeny is believed to have taken place between 620 and 600 Ma as these terrane collided with a major continental mass to the east referred to here as the eastern Arabian block (EAB). The Mizil gneiss dome is therefore considered to have formed in a convergent contractional setting rather than being the outcome of extensional post-orogenic collapse.

  17. Augen gneisses versus Augen gneisses from the Jaguaribeana Belt, northeastern region from Brazil: stratigraphy, geochemistry and U-Pb ages

    International Nuclear Information System (INIS)

    Sa, Jaziel Martins; Silva, Elvis Roberto da; Bertrand, Jean Michel; Leterrier, Jacques

    1997-01-01

    The Jaguaribeana Belt is located at Borborema Province, Ceara State, Brazil and this study aims to present Uranium-Lead (U-Pb) data and the augen gneisses petrographic and geochemical study of the Jaguaribe Belt, and to realize comparisons between these and the augen gneisses from the Oros Belt. It describes the geological characteristics of this region, the augen gneisses petrography and geochemical data and the U-Pb method results for a discussion about the augen gneisses from the Oros and Jaguaribe Belt

  18. Gravity signatures of terrane accretion

    Science.gov (United States)

    Franco, Heather; Abbott, Dallas

    1999-01-01

    In modern collisional environments, accreted terranes are bracketed by forearc gravity lows, a gravitational feature which results from the abandonment of the original trench and the initiation of a new trench seaward of the accreted terrane. The size and shape of the gravity low depends on the type of accreted feature and the strength of the formerly subducting plate. Along the Central American trench, the accretion of Gorgona Island caused a seaward trench jump of 48 to 66 km. The relict trench axes show up as gravity lows behind the trench with minimum values of -78 mgal (N of Gorgona) and -49 mgal (S of Gorgona) respectively. These forearc gravity lows have little or no topographic expression. The active trench immediately seaward of these forearc gravity lows has minimum gravity values of -59 mgal (N of Gorgona) and -58 mgal (S of Gorgona), respectively. In the north, the active trench has a less pronounced gravity low than the sediment covered forearc. In the Mariana arc, two Cretaceous seamounts have been accreted to the Eocene arc. The northern seamount is most likely a large block, the southern seamount may be a thrust slice. These more recent accretion events have produced modest forearc topographic and gravity lows in comparison with the topographic and gravity lows within the active trench. However, the minimum values of the Mariana forearc gravity lows are modest only by comparison to the Mariana Trench (-216 mgal); their absolute values are more negative than at Gorgona Island (-145 to -146 mgal). We speculate that the forearc gravity lows and seaward trench jumps near Gorgona Island were produced by the accretion of a hotspot island from a strong plate. The Mariana gravity lows and seaward trench jumps (or thrust slices) were the result of breaking a relatively weak plate close to the seamount edifice. These gravity lows resulting from accretion events should be preserved in older accreted terranes.

  19. Some contrasting biostratigraphic links between the Baker and Olds Ferry Terranes, eastern Oregon

    Science.gov (United States)

    Nestell, Merlynd K.; Blome, Charles D.

    2016-01-01

    New stratigraphic and paleontologic data indicate that ophiolitic melange windows in the Olds Ferry terrane of eastern Oregon contain limestone blocks and chert that are somewhat different in age than those present in the adjacent Baker terrane melange. The melange windows in the Olds Ferry terrane occur as inliers in the flyschoid Early and Middle Jurassic age Weatherby Formation, which depositionally overlies the contact between the melange-rich Devonian to Upper Triassic rocks of the Baker terrane on the north, and Upper Triassic and Early Jurassic volcanic arc rocks of the Huntington Formation on the south. The Baker terrane and Huntington Formation represent fragments of a subduction complex and related volcanic island arc, whereas the Weatherby Formation consists of forearc basin sedimentary deposits. The tectonic blocks in the melange windows of the Weatherby Formation (in the Olds Ferry terrane) are dated by scarce biostratigraphic evidence as Upper Pennsylvanian to Lower Permian and Upper Triassic. In contrast, tectonic blocks of limestone in theBaker terrane yield mostly fusulinids and small foraminifers of Middle Pennsylvanian Moscovian age at one locality.Middle Permian (Guadalupian) Tethyan fusulinids and smaller foraminifers (neoschwagerinids and other Middle Permian genera) are present at a few other localities. Late Triassic conodonts and bryozoans are also present in a few of the Baker terrane tectonic blocks. These limestone blocks are generally embedded in Permian and Triassic radiolarian bearing chert or argillite. Based on conodont, radiolarian and fusulinid data, the age limits of the meange blocks in the Weatherby Formation range from Pennsylvanian to Late Triassic.

  20. Durability analysis of gneiss using wear resistance

    Directory of Open Access Journals (Sweden)

    José Luiz Ernandes Dias Filho

    2014-01-01

    Full Text Available This paper presents a study conducted in gneiss in Santo Antonio de Pádua, RJ, BR, including durability analysis of the rock using slake durability test. Rocks in the region of Pádua are mostly used for ornamental purposes. A lab equipment was developed to evaluate the influence of rotation in the test, allowing for the speed variation of 7 RPM to 238 RPM. This study could be implemented in a wide variety of rock materials, targeting them according to their lifetime in the project. With variation of the wear levels, increasing weight loss was observed until the inertia moment in which the sample holds to the machine wall. The results indicate an increase in linear mass loss. These procedures allow a more precise analysis of durability than can be applied in different different regions of the world.

  1. Reconnaissance Rb-Sr dates for the Himalayan Central Gneiss, Northwest India

    International Nuclear Information System (INIS)

    Powell, C. McA.; Crawford, A.R.; Armstrong, R.L.; Wynne-Edwards, H.R.; Prakash, R.

    1979-01-01

    Rb-Sr analysis of whole-rock samples and biotite and biotite - or muscovite - whole rock pairs suggests that the Himalayan Central Gneiss in the crystalline nappes of the Lesser Himalaya and the root zone in the High Himalaya was formed during Oligocene to mid-Miocene times by deformation and metamorphism of older rocks, including Precambrian. Four whole-rock samples from the Almora-Askot thrust sheets define an isochron of 1620 +- 90 Ma with a high initial 87 Sr/ 86 Sr ratio of 0.749 +- 0.007; other single whole-rock samples give dates in the range 268 to 1065 Ma, assuming an initial 87 Sr/ 86 Sr ratio of 0.704. These dates are considered to represent either depositional or early instructive/deformational events. Three biotite-whole rock pairs from the root zone of the Himalayan Central Gneiss in Lahaul give aqes of 16 to 19 Ma and two muscovite-whole rock pairs give similar mid-Cenozoic ages (12 and 26 Ma); two muscovite-whole rock pairs give Paleozoic ages, which suggests incomplete resetting of the muscovite by the Cenozoic metamorphism. The pattern of ages is similar to recent results from adjacent areas, and consistent with models of Himalayan tectonics involving formation of the Central Gneiss from older Indian crust during the mid-Cenozoic. (auth.)

  2. Precambrian terranes of African affinities in the southeastern part of Brazil and Uruguay

    International Nuclear Information System (INIS)

    Basei, M.A.S; Junior, Siga; Harara, O.M; Preciozzi, F; Sato, K; Kaufuss, G

    2001-01-01

    distinct, representing the main suture that separates the terranes of African and South-American affinities. As observed in figure 1, it is considered in this article that the region of African affinity is constituted by the terrains located east of the Major Gercino-Sierra Ballena suture zone, being represented by two major units: the Granite Belt - outcropping along the whole eastern portion of the Brazilian southern region, and the Punta del Este terrain (PET) south-easternmost of Uruguay. The Punta del Este Terrane (PET) is composed of a series of gneisses and migmatites formed in the 1000-900 Ma interval, according to Preciozzi et al. (1999; Basei et al 2000), intensely reworked during the Rio Doce orogeny (600-500 Ma). These authors proposed that the terranes situated east of the Alferes-Cordilheira Shear Zone should not integrate the Granite Belt, suggesting that this crustal segment represent in South America terranes related to the Namaqua Belt recognized in the southwestern portion of the African continent. Similar terranes have not been recognized in Brazil and Argentina. In PET, three major tectonic units can be characterized: a gneissic-migmatitic basement, a low-grade metasedimentary cover (Rocha Group) and a post-tectonic series that includes alkaline granitoids and acid volcanic rocks. Considering that the PET basement correlates with the Namaqua Complex gneisses, the Rocha Group was tentatively correlated with the Gariep Group supracrustal units (au)

  3. Geochemical Constraints for Mercury's PCA-Derived Geochemical Terranes

    Science.gov (United States)

    Stockstill-Cahill, K. R.; Peplowski, P. N.

    2018-05-01

    PCA-derived geochemical terranes provide a robust, analytical means of defining these terranes using strictly geochemical inputs. Using the end members derived in this way, we are able to assess the geochemical implications for Mercury.

  4. A tectonic reconstruction of accreted terranes along the paleo-Pacific margin of Gondwana

    Science.gov (United States)

    Bammel, Brandon

    The southern oceanic margin of Gondwana was nearly 40,000 km long or 24,854.8 miles. The southern margin was the result of the Terra Australis orogen. Spanning 18,000 km or 11,184.7 miles and is proposed as one of the largest and longest lived orogens in Earth history. The paleo-Pacific margin of Gondwana consisted of segments of the Australian-Antarctic craton, southern South America (modern Argentina and Chile), southern South Africa, Marie Byrdland, New Zealand and its adjacent continental shelf, the Ellsworth Mountains, and the Transantarctic Mountains. The process of terrane accretion has played a substantial part in the assembly of the continents as they look today. The paleo-Pacific margin of Gondwana was an active region of terrane accretion from the Neoproterozoic to the Late Mesozoic. This research study examines the accretion of terranes across the paleo-Pacific Gondwana margin to provide a comprehensive reconstruction. A paleogeographic basemap was created using PALEOMAP Project maps and the geology data was provided by the School of Geoscience from the University of Witwatersrand of South Africa. Location and data analyzed for terranes were collected building a PDF library of journal articles across numerous geological publications.

  5. Circum-North Pacific tectonostratigraphic terrane map

    Science.gov (United States)

    Nokleberg, Warren J.; Parfenov, Leonid M.; Monger, James W.H.; Baranov, Boris B.; Byalobzhesky, Stanislav G.; Bundtzen, Thomas K.; Feeney, Tracey D.; Fujita, Kazuya; Gordey, Steven P.; Grantz, Arthur; Khanchuk, Alexander I.; Natal'in, Boris A.; Natapov, Lev M.; Norton, Ian O.; Patton, William W.; Plafker, George; Scholl, David W.; Sokolov, Sergei D.; Sosunov, Gleb M.; Stone, David B.; Tabor, Rowland W.; Tsukanov, Nickolai V.; Vallier, Tracy L.; Wakita, Koji

    1994-01-01

    The companion tectonostratigraphic terrane and overlap assemblage of map the Circum-North Pacific presents a modern description of the major geologic and tectonic units of the region. The map illustrates both the onshore terranes and overlap volcanic assemblages of the region, and the major offshore geologic features. The map is the first collaborative compilation of the geology of the region at a scale of 1:5,000,000 by geologists of the Russian Far East, Japanese, Alaskan, Canadian, and U.S.A. Pacific Northwest. The map is designed to be a source of geologic information for all scientists interested in the region, and is designed to be used for several purposes, including regional tectonic analyses, mineral resource and metallogenic analyses (Nokleberg and others, 1993, 1994a), petroleum analyses, neotectonic analyses, and analyses of seismic hazards and volcanic hazards. This text contains an introduction, tectonic definitions, acknowledgments, descriptions of postaccretion stratified rock units, descriptions and stratigraphic columns for tectonostratigraphic terranes in onshore areas, and references for the companion map (Sheets 1 to 5). This map is the result of extensive geologic mapping and associated tectonic studies in the Russian Far East, Hokkaido Island of Japan, Alaska, the Canadian Cordillera, and the U.S.A. Pacific Northwest in the last few decades. Geologic mapping suggests that most of this region can be interpreted as a collage of fault-bounded tectonostratigraphic terranes that were accreted onto continental margins around the Circum-

  6. Geochemical trends in the weathered profiles above granite gneiss ...

    African Journals Online (AJOL)

    Geochemical trends in the weathered profiles above granite gneiss and schist of Abeokuta area, southwestern Nigeria. Anthony T Bolarinwa, Anthony A Elueze. Abstract. No Abstract. Journal of Mining and Geology 2005, Vol. 41(1): 19-31. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT ...

  7. The ophiolitic North Fork terrane in the Salmon River region, central Klamath Mountains, California

    Science.gov (United States)

    Ando, C.J.; Irwin, W.P.; Jones, D.L.; Saleeby, J.B.

    1983-01-01

    Jurassic thrust faults.The North Fork terrane appears to contain no arc volcanic rocks or arc-derived detritus, suggesting that it neither constituted the base for an arc nor was in a basinal setting adjacent to an arc sediment source. Details of the progressive accretion and evolutionary relationship of the North Fork to other terranes of the Klamath Mountains are not yet clear.

  8. Late Cretaceous tectonothermal evolution of the southern Lhasa terrane, South Tibet: Consequence of a Mesozoic Andean-type orogeny

    Science.gov (United States)

    Dong, Xin; Zhang, Ze-ming; Klemd, Reiner; He, Zhen-yu; Tian, Zuo-lin

    2018-04-01

    The Lhasa terrane of the southern Tibetan Plateau participated in a Mesozoic Andean-type orogeny caused by the northward subduction of the Neo-Tethyan oceanic lithosphere. However, metamorphic rocks, which can unravel details of the geodynamic evolution, are rare and only exposed in the south-eastern part of the Lhasa terrane. Therefore, we conducted a detailed petrological, geochemical and U-Pb zircon geochronological study of the late Cretaceous metamorphic rocks and associated gabbros from the Nyemo inlier of the southern Lhasa terrane. The Nyemo metamorphic rocks including gneisses, schists, marbles and calc-silicate rocks, experienced peak amphibolite-facies contact metamorphism under P-T conditions of 3.5-4.0 kbar and 642-657 °C with a very high geothermal gradient of 45-50 °C/km, revealing a distinct deflection from the steady-state geotherm during low-pressure metamorphism. Inherited magmatic zircon cores from the metamorphic rocks yielded protolith ages of 197-194 Ma, while overgrowth zircon rims yielded metamorphic ages of ca. 86 Ma. Whole-rock chemistry and zircon Hf isotopes suggest that the protoliths of the gneisses and schists are andesites and tuffs of the early Jurassic Sangri Group, which were derived from a depleted mantle source of a continental arc affinity. The coeval intimately-associated gabbro (ca. 86 Ma) crystallized under P-T conditions of 3.5-5.3 kbar and 914-970 °C, supplying the heat flux high enough to cause the contact metamorphism of the Sangri Group rock types. We propose that the intrusion of the gabbro and a simultaneous pressure increase of up to 4.0 kbar, which is related to crustal thickening due to crustal overthrusting and the intrusion of mafic material, resulted in the late Cretaceous metamorphism of the early Jurassic Sangri Group during an Andean-type orogeny. Furthermore the Nyemo metamorphic rocks, which have previously been considered to represent slivers of the Precambrian metamorphic basement of the Lhasa terrane

  9. Lower precambrian of the Keivy Terrane, Northeastern Baltic Shield: A stratigraphic succession or a collage of tectonic sheets?

    Science.gov (United States)

    Balagansky, V. V.; Raevsky, A. B.; Mudruk, S. V.

    2011-03-01

    The Keivy Terrane in the northeastern Baltic Shield appreciably differs from the adjacent tectonic blocks. In the northwestern part of this terrane (the Serpovidny Range), an outlier of Paleoproterozoic supracrustal rocks called the Serpovidny structure is surrounded by Archean (?) Keivy high-alumina paraschists. As follows from structural and magnetic data, the Paleoproterozoic rocks are deformed into a tight sheath fold 8 × 2 km in size at the surface and 5 km in length along the sheath axis. Faults parallel to the boundaries of the layers and locally cutting them off at an acute angle are involved in folding as well. The outer boundaries of the Serpovidny structure are tectonic. This structure is complementary to a larger tectonic lens composed of the Keivy mica schists. It is concluded that all of the supracrustal rocks of the Serpovidny Range are in fact tectonic sheets and lenses deformed into sheath folds. The literature data show that kilometer-scale sheath folds occur throughout the Keivy paraschist belt and most likely were formed owing to thrusting of the Murmansk Craton onto the Keivy Terrane in the south-southwestern direction. Foliation and lineation related to thrusting have been established in the Archean silicic metavolcanics and peralkaline granites occupying the most part of the terrane. In contrast, the granitoids and gabbroanorthosites of the Archean basement, which form a block 90 × 20 km in the southwestern Keivy Terrane, were not affected by Paleoproterozoic deformation. In other words, a detached assembly of tectonic sheets composed of the upper and middle crustal rocks that underwent deformation at the initial stage of the Paleoproterozoic Lapland-Kola Orogeny and the Archean basement, which is free of this deformation, are distinguished. The depth of detachment is estimated at 20-25 km. The detachment of the upper and middle crust in the Keivy Terrane and its position in the structure of the Baltic Shield are consistent with a

  10. Detrital zircon ages in Buller and Takaka terranes, New Zealand : constraints on early Zealandia history

    International Nuclear Information System (INIS)

    Adams, C.J.; Mortimer, N.; Campbell, H.J.; Griffin, W.L.

    2015-01-01

    Detrital zircon ages are presented for 34 early Palaeozoic sandstones from Buller and Takaka terranes, New Zealand, and formerly adjacent parts of Australia-Antarctica. The Buller-Takaka datasets always have two major groups: Ordovician-late Neoproterozoic, 444-700 Ma (but mainly 540-700 Ma), termed 'Gondwana Assembly' (GA), and early Neoproterozoic-Mesoproterozoic, 700-1600 Ma (but mainly 900-1200 Ma), termed 'Rodinia Assembly' (RA). In both terranes, significant age components within these groups are strikingly similar and also have RA/GA ratios, 0.6-1.8. The Cambrian volcanic arc of the Takaka Terrane has contributed little to the zircon patterns. Proportions of Late Cambrian-Early Ordovician zircons, characteristic of granitoid sources in the Ross-Delamerian Orogen are low. The zircons are predominantly reworked with contemporary zircons only evident in a few Buller datasets. The zircon patterns suggest that two major sources (late Mesoproterozoic and late Neoproterozoic), enduring over 120 Ma, were widely distributed and it is postulated they form Precambrian basement beneath southern Zealandia. (author).

  11. Punta del este terrane: meso proterozoic basement and neo proterozoic cover

    International Nuclear Information System (INIS)

    Preciozzi, F.; Sanchez Bettucci, L.; Basei, M.; Peel, E.; Oyhantcabal, P.; Cordani, U.

    2003-01-01

    Full text: Eastern basement of Uruguay consists of Meso and Neoproterozoic rocks. Mesoproterozoic basement had been deformed by pre-Brasiliano and Brasiliano events. Regional variations in this basement and in the Neoproterozoic cover show equivalent deformation styles and intensities. Models proposed for tectonic evolution have been scarce and confusing. Specially, the ones that concern the moment of collision and/or juxtaposition of blocks. The Punta del Este Terrane (PET) is composed of gneisses and migmatites formed between 1000 Ma to 900 Ma (Preciozzi et al., 2001). These rocks had been strongly reworked during Brasiliano and Rio Doce orogenesis (ca. 900-500 Ma). This crustal segment represents a high grade metamorphic terrane, which is correlated to some gneissic complexes southwest of Africa. Particularly, it is correlated to Kibaran-Namaqua Belt in Namibia. U-Pb ages between 1000 Ma and 900 Ma, obtained in zircons from tonalitic granitoids, are interpreted as indicative of their crystallization (Fig. 1). Besides, anatectic fluids related to migmatites leucosomes yielded ages of ca. 520 to 540 Ma. This denotes that superimposed metamorphic conditions during Brasiliano orogenesis reached, at least, lower amphibolite facies. PET basement gneisses present Sm-Nd model ages (TDM) between 2.4 to 1.8 Ga, showing long crustal residence, corroborated by the very negative εNd values of –1.3 and –14.3. During Brazilian orogenesy they were affected by deformation processes and anatexis. Metasedimentary PET cover occurs near La Paloma and Rocha towns. It is represented by a siliciclastic metasedimentary succession corresponding to the Rocha formation. In La Pedrera town recognized three sedimentary facies were (1-3): (1) sandstones and pelites; (2) green pelites; and (3) rhytmites. The transition from facies (1) to facies (3) shows the passage from fluvial environment with tidal influence to tidal flat with predominance of sub tidal deposits (Pazos and S

  12. The complex systematics of zircons in migmatitic gneisses: An example from an Archean migmatite along the Patos Shear Zone, Borborema Province, NE Brazil

    International Nuclear Information System (INIS)

    Costa, A.C.D; Hackspacher, P.C; Dantas, E.L; Fetter, A.H.

    2001-01-01

    The Northem Tectonic Domain Borborema Province, in Northeast of Brazil records a complex history of tectonic activity ranging from 3.4 Ga to 0.6 Ga (Brito Neves, 1995 and Dantas, 1996). U-Pb systematics of zircons from a migmatitic gneiss just north of the Patos Shear Zone provide an excellent example of the difficulties encountered using conventional single-grain U/Pb zircon geochronology in polydeformed gneiss terranes. Our conventional single grain zircon analyses of a migmatite yielded Archean ages between ca. 3.3 at 2.8 a, as well as some highly discordant Paleoproterozoic ages. Subsequent cathodoluminescence images of these zircon grains showed complex internal structures that possibly record up to 4 separate stages of zircon growth. With such internal complexity, is impossible resolve primary crystallization ages as well as the ages of subsequent overgrowth events using conventional single grain analyses. Such resolution will require analyses of the individual grain domains using the SHRIMP method (au)

  13. Effects of silicate weathering on water chemistry in forested, upland, felsic terrane of the USA

    International Nuclear Information System (INIS)

    Stauffer, R.E.; Wittchen, B.D.

    1991-01-01

    The authors use data from the US EPA National Surface Water Survey (NSWS), the USGS Bench-Mark Station monitoring program, and the National Acid Deposition Program (NADP) to evaluate the role of weathering in supplying base cations to surface waters in forested, upland, felsic terrane of the northeastern, northcentral, and northwestern (Idaho batholith) US. Multivariate regression reveals differential effects of discharge on individual base cations and silica, but no secular trend in the Ca/Na denudation rate over 24 yr (1965-1988) for the Wild River catchment in the White Mountains. Because the turn-over time for Na in the soil-exchange complex is only ca. 1.5 yr, the long-term behavior of the ratios Ca/Na and Si/Na in waters leaving this catchment indicates that weathering is compensating for base cation export. In every subregion, Ca and Mg concentrations in lakes are statistically linked to nonmarine Na, but the median Ca/Na ratio is greater than the ratio in local plagioclase. The authors attribute this inequality to nonstoichiometric weathering of calcium in juvenile (formerly glaciated) terrane, not to leaching of exchangeable cations by So 4 because intraregional and cross-regional statistical analysis reveals no effect of atmospherically derived sulfate ion. The median base cation denudation rates (meq m -2 yr -1 ) for these American lake regions are: Maine granites (108); western Adirondack felsic gneiss (85); Vermilion batholith (42); Idaho batholith (52). The regional rates are high enough to compensate for present wet deposition of acidifying anions except in some vulnerable lake watersheds in the western Adirondacks

  14. Age and duration of eclogite-facies metamorphism, North Qaidam HP/UHP terrane, Western China

    Science.gov (United States)

    Mattinson, C.G.; Wooden, J.L.; Liou, J.G.; Bird, D.K.; Wu, C.L.

    2006-01-01

    Amphibolite-facies para-and orthogneisses near Dulan, at the southeast end of the North Qaidam terrane, enclose minor eclogite and peridotite which record ultra-high pressure (UHP) metamorphism associated with the Early Paleozoic continental collision of the Qilian and Qaidam microplates. Field relations and coesite inclusions in zircons from paragneiss suggest that felsic, mafic, and ultramafic rocks all experienced UHP metamorphism and a common amphibolite-facies retrogression. SHRIMP-RG U-Pb and REE analyses of zircons from four eclogites yield weighted mean ages of 449 to 422 Ma, and REE patterns (flat HREE, no Eu anomaly) and inclusions of garnet, omphacite, and rutile indicate these ages record eclogite-facies metamorphism. The coherent field relations of these samples, and the similar range of individual ages in each sample suggests that the ???25 m.y. age range reflects the duration of eclogite-facies conditions in the studied samples. Analyses from zircon cores in one sample yield scattered 433 to 474 Ma ages, reflecting partial overlap on rims, and constrain the minimum age of eclogite protolith crystallization. Inclusions of Th + REE-rich epidote, and zircon REE patterns are consistent with prograde metamorphic growth. In the Lu??liang Shan, approximately 350 km northwest in the North Qaidam terrane, ages interpreted to record eclogite-facies metamorphism of eclogite and garnet peridotite are as old as 495 Ma and as young as 414 Ma, which suggests that processes responsible for extended high-pressure residence are not restricted to the Dulan region. Evidence of prolonged eclogite-facies metamorphism in HP/UHP localities in the Northeast Greenland eclogite province, the Western Gneiss Region of Norway, and the western Alps suggests that long eclogite-facies residence may be globally significant in continental subduction/collision zones.

  15. Punta del Este terrane : a better knowledge

    International Nuclear Information System (INIS)

    Preciozzi, F.; Sanchez Bettucci, L; Basei, M.

    2002-01-01

    Field Punta del Este (TPE) is constituted by a series of gneisses and migmatites formed in the range of 1000 and 900 Ma, and have been intensely reworked during Rio Doce orogeny (ca. 600-500 Ma). This cortical segment represents high-grade metamorphic terrain, correlatable with complex gneiss Southwest Africa, particularly with Kibariáno Belt - Namaqualanos recognized in the southwestern portion of Africa (Namibia). U-Pb zircon ages in tonalite granitoids indicate values ​​between 1000 and 900 Ma and were interpreted as indicating the time of generation of these rocks. This should also be the age of high-grade metamorphism that affected a large part of the gneissic rocks of the region. Moreover, the anatectic related mobilized leucosomes ages of migmatites gave ca. 520-540 Ma, indicating that the metamorphic conditions (overlapping) during the Rio Doce orogeny reached at least the amphibolite facies. The metasedimentary cover TPE occurs in the vicinity of the towns of La Paloma Rocha. These are represented by a siliciclastic metasedimentary sequence represented by Rocha Formation. Despite the poly phase deformation and low grade metamorphism affecting this training, primary structures are common such as stratification plano-parallel, cross-bedding, hummock y and massive levels with gradational stratification

  16. Cenozoic extensional tectonics of the Western Anatolia Extended Terrane, Turkey

    International Nuclear Information System (INIS)

    Cemen, I; Catlos, E J; Gogus, O; Diniz, E; Hancer, M

    2008-01-01

    The Western Anatolia Extended Terrane in Turkey is located on the eastern side of the Aegean Extended Terrane and contains one of the largest metamorphic core complexes in the world, the Menderes massif. It has experienced a series of continental collisions from the Late Cretaceous to the Eocene during the formation of the Izmir-Ankara-Erzincan suture zone. Based our field work and monazite ages, we suggest that the north-directed postcollisional Cenozoic extension in the region is the product of three consecutive stages, triggered by three different mechanisms. The first stage was initiated about 30 Ma ago, in the Oligocene by the Orogenic Collapse the thermally weakened continental crust along the north-dipping Southwest Anatolian shear zone. The shear zone was formed as an extensional simple-shear zone with listric geometry at depth and exhibits predominantly normal-slip along its southwestern end. But, it becomes a high-angle oblique-slip shear zone along its northeastern termination. Evidence for the presence of the shear zone includes (1) the dominant top to the north-northeast shear sense indicators throughout the Menderes massif, such as stretching lineations trending N10E to N30E; and (2) a series of Oligocene extensional basins located adjacent to the shear zone that contain only carbonate and ophiolitic rock fragments, but no high grade metamorphic rock fragments. During this stage, erosion and extensional unroofing brought high-grade metamorphic rocks of the Central Menderes massif to the surface by the early Miocene. The second stage of the extension was triggered by subduction roll-back and associated back-arc extension in the early Miocene and produced the north-dipping Alasehir and the south-dipping Bueyuek Menderes detachments of the central Menderes massif and the north-dipping Simav detachment of the northern Menderes massif. The detachments control the Miocene sedimentation in the Alasehir, Bueyuek Menderes, and Simav grabens, containing high

  17. Strength and strain anisotropy of olkiluoto mica gneiss

    International Nuclear Information System (INIS)

    Hakala, M.; Kuula, H.; Hudson, J.

    2006-10-01

    An anisotropy in the elastic moduli values of intact rock with a ratio of more than 1.3∼1.5 has been reported to have an effect on the calculated magnitudes and orientations of the in situ principal stress components as measured by the overcoring method. Work related to the on-going site investigation for a deep radioactive waste repository at the Olkiluoto site in Western Finland has shown that the migmatic mica gneiss is anisotropic which could therefore affect the interpretation of overcoring stress measurement results. This paper includes a summary of the theory of anisotropy concerning the intact rock moduli via the strain compliance matrix, a description of the core sample testing methods, and interpretation of results for the migmatic mica gneiss from two site investigation boreholes. In this case study, 19 specimens were tested and the results showed a modulus anisotropy of about 1.4. Because such anisotropy is high enough to produce significant errors in the estimation of the in situ principal stresses, it is recommended to take this into account in the interpretation of the stress measurement results, both in the context of the current work in Finland and in other projects where similar anisotropy is encountered. (orig.)

  18. Linking Tengchong Terrane in SW Yunnan with Lhasa Terrane in southern Tibet through magmatic correlation

    Science.gov (United States)

    Xie, Jincheng; Zhu, Dicheng; Dong, Guochen; Zhao, Zhidan; Wang, Qing

    2016-04-01

    New zircon U-Pb data, along with the data reported in the literature, reveal five phases of magmatic activity in the Tengchong Terrane since the Early Paleozoic with spatial and temporal variations summarized as: Cambrian-Ordovician (500-460 Ma) to the eastern, minor Triassic (245-206 Ma) in the eastern and western, abundant Early Cretaceous (131-114 Ma) in the eastern, extensive Late Cretaceous (77-65 Ma) in the central, and Paleocene-Eocene (65-49 Ma) in the central and western Tengchong Terrane, in which the Cretaceous-Eocene magmatism was migrated from east to west (Xu et al., 2012). The increased zircon eHf(t) of the Early Cretaceous granitoids from -12.3 to -1.4 at ca. 131-122 Ma to -4.6 to +7.1 at ca. 122-114 Ma identified for the first time in this study and the magmatic flare-up at ca. 53 Ma in the central and western Tengchong Terrane (Wang et al., 2014, Ma et al., 2015) indicate the increased contributions from mantle- or juvenile crust-derived components. The spatial and temporal variations and changing magmatic compositions with time in the Tengchong Terrane closely resemble the Lhasa Terrane in southern Tibet. Such similarities, together with the data of stratigraphy and paleobiogeography (Zhang et al., 2013), enable us to propose that the Tengchong Terrane in SW Yunnan is most likely linked with the Lhasa Terrane in southern Tibet, both of which experience similar tectonomagmatic histories since the Early Paleozoic. References Ma, L.Y., Wang, Y.J., Fan, W.M., Geng, H.Y., Cai, Y.F., Zhong, H., Liu, H.C., Xing, X.W., 2014. Petrogenesis of the early Eocene I-type granites in west Yingjiang (SW Yunnan) and its implication for the eastern extension of the Gangdese batholiths. Gondwana Research 25, 401-419. Wang, Y.J., Zhang, L.M., Cawood, P.A., Ma, L.Y., Fan, W.M., Zhang, A.M., Zhang, Y.Z., Bi, X.W., 2014. Eocene supra-subduction zone mafic magmatism in the Sibumasu Block of SW Yunnan: Implications for Neotethyan subduction and India-Asia collision

  19. Experimental Researches on Long-Term Strength of Granite Gneiss

    Directory of Open Access Journals (Sweden)

    Lin Liu

    2015-01-01

    Full Text Available It is important to confirm the long-term strength of rock materials for the purpose of evaluating the long-term stability of rock engineering. In this study, a series of triaxial creep tests were conducted on granite gneiss under different pore pressures. Based on the test data, we proposed two new quantitative methods, tangent method and intersection method, to confirm the long-term strength of rock. Meanwhile, the isochronous stress-strain curve method was adopted to make sure of the accuracy and operability of the two new methods. It is concluded that the new methods are suitable for the study of the long-term strength of rock. The effect of pore pressure on the long-term strength of rock in triaxial creep tests is also discussed.

  20. Alkaline / peralkaline gneisses near the northern margin of the Natal structural and metamorphic province

    International Nuclear Information System (INIS)

    Scogings, A.J.

    1990-01-01

    Alkaline / peralkaline gneisses occur within three granitoid complexes at Ngoye, Bull's Run and Wangu, near the northern margin of the Natal Structural and Metamorphic Province. A wide range of rock types is present, from nepheline syenite gneisses through to peralkaline granite gneisses, with minor carbonatite and monzodiorite gneiss intrusive phases noted within two of the bodies. It is suggested that the three alkaline gneiss occurences so far mapped constitute the remnants of a metamorphosed alkaline magmatic province, and that such magmatism occured either in a post-collisional or anorogenic post-D1, pre-D2 tectonic setting. The three complexes are described with respect to mineralogy and chemistry, followed by a brief overview of the possible tectonic setting at the time of their intrusion. 1 tab., 3 refs

  1. Tectonostratigraphic terranes of the frontier circum-Pacific region

    Energy Technology Data Exchange (ETDEWEB)

    Howell, D.G.; Jones, D.L.; Schermer, E.R.

    1983-03-01

    Many major exploration frontiers around the Pacific are in regions where complex geologic relations reflect plate-tectonic processes, crustal mobility, and accretion of exotic terranes. The destruction of the proto-Pacific ocean (Panthalassa) involved accretion of terranes to cratonal regions such as Gondwana and Laurasia. Terranes in southwestern New Zealand and eastern Antarctica were also probably accreted during the Paleozoic. The southern margin of Siberia, extending into China, underwent a protracted period of accretion from the late Precambrian through the early Mesozoic. Mid-Paleozoic accretion is reflected in the Innuitian foldbelt of the Arctic Ocean, the Black Clastic unit of the northern Rocky Mountains, and the Antler orogeny of the western US cordillera. The Mesozoic breakup of Pangaea and the acceleration of subduction aided in the rifting and dispersal of terranes from equatorial paleolatitudes. Fragments of these terranes now compose much of the continental margins of the Pacific basin, including New Zealand, Indochina, southern China, southeast Siberia, the North American cordillera, and South America. Some terranes are presently being further fragmented by post-accretionary dispersion processes such as strike-slip faulting in western North America and Japan. Although the character and distribution of terranes in the western US are fairly well documented, details are needed for other terranes around the Pacific basin. Interpretation of structure and stratigraphy at depth will be aided by more data on the timing of accretion and the nature of deformation associated with accretion and dispersion. Such data are needed for further define specific exploration targets in the circum-Pacific region.

  2. Geochronology of Zircon in Eclogite Reveals Imbrication of the Ultrahigh-Pressure Western Gneiss Region of Norway.

    Science.gov (United States)

    Young, D. J.; Kylander-Clark, A. R.; Root, D. B.

    2014-12-01

    Eclogite provides the only record of kinematic events at the deepest levels of orogens. Integrating the U-Pb geochronology and trace element chemistry of zircon in eclogite reveals the most complete view of the PTt history, yet low concentrations of uranium and zirconium and drier compositions that hinder zircon growth at peak conditions render it a challenging rocktype for this approach. The iconic Western Gneiss Region (WGR) in Norway is one of the largest terranes of deeply subducted continental rocks in the world, and contains many indicators of ultrahigh-pressure metamorphic conditions (P>2.8 GPa) that developed during the Siluro-Devonian Caledonian Orogeny. A metamorphic transition from amphibolite-facies to ultrahigh-pressure eclogite facies broadly coincides with a km-scale shear zone that underlies the majority of the WGR. A critical unknown is the timing of movement on this feature, which emplaced allochthonous units above the Baltica basement, but might also have accommodated late-orogenic exhumation of the WGR from mantle depths. We carried out laser ablation split-stream ICPMS (LASS) and selected multigrain TIMS analyses of zircons from eleven eclogites across the southern WGR, of which eight are located within or above the shear zone. LASS spots on polished grains mostly yield weakly discordant Proterozoic intrusive ages, and often minimal indication of a Caledonian (U)HP metamorphic overprint. Direct ablation into unpolished zircon reveals thin rims of Caledonian age in some cases. Overall, the dataset shows that all samples began zircon growth at approximately the same time (ca. 430-420 Ma). Eclogite from lower levels of the shear zone does not contain any dates younger than ca. 410 Ma, however, while eclogite from higher levels continued growth until ca. 400 Ma. We interpret this to result from thrusting of the WGR above cooler basement after 410 Ma, terminating new zircon crystallization within the shear zone but allowing limited further growth in

  3. Measurements of cesium and strontium diffusion in biotite gneiss

    International Nuclear Information System (INIS)

    Skagius, K.; Neretnieks, I.

    1988-01-01

    A significant retardation of radionuclides transported by flowing water from an underground repository can be expected if the nuclides are able to diffuse into the water filled micropores in the rock. This diffusion into the pores will also increase the surface available to interactions between the nuclides in the ground water and the rock material, such as sorption. To calculate the retardation, it is necessary to know the sorption properties and the diffusivities in the rock matrix for the radionuclides. Diffusion experiments with cesium and strontium in biotite gneiss samples have been performed. Both the transport of strontium and cesium through rock samples and the concentration profiles of cesium and strontium inside rock samples have been determined. The result shows that diffusion of cesium and strontium occurs in the rock material. A diffusion model has been used to evaluate the diffusivity. Both pore diffusion and surface diffusion had to be included in the model to give good agreement with the experimental data. If surface diffusion is not included in the model, the effective pore diffusivity that gives the best fit to the experimental data is found to be higher than expected from earlier measurement of iodide diffusion in the same type of rock material. This indicates that the diffusion of cesium and strontium (sorbing components) in rock material is caused by both pore diffusion and surface diffusion acting in parallel

  4. Diffusion measurements of cesium and strontium in biotite gneiss

    International Nuclear Information System (INIS)

    Skagius, K.; Neretnieks, I.

    1985-01-01

    A significant retardation of radionuclides transported by flowing water from an underground repository can be expected if the nuclides are able to diffuse into the water filled micropores in the rock. This diffusion into the pores will also increase the surface available to interaction between the nuclides in the groundwater and the rock material, such as sorption. To calculate the retardation it is necessary to know the sorption properties and the diffusivities in the rock matrix for the radionuclides. Diffusion experiments with cesium and strontium in biotite gneiss samples have been performed. Both the transport of strontium and cesium through rock samples and the concentration profiles of cesium and strontium inside rock samples have been determined. The result show that diffusion of cesium and strontium occurs in the rock material. A diffusion model has been used to evaluate the diffusivity. Both pore diffusion and surface diffusion had to be included in the model to give good agreement with the experimental data. If surface diffusion is not included in the model, the effective pore diffusivity that gives the best fit to the experimental data is found to be higher than expected from earlier measurements of iodide diffusion in the same type of rock material. This indicates that the diffusion of cesium and strontium (sorbing components) in rock material is caused by both pore diffusion and surface diffusion acting in parallel. (author)

  5. The basement of the Punta de Este Terrane: A meso proterozoic heritage at the eastern border of Rio de La Plata craton

    International Nuclear Information System (INIS)

    Preciozzi, F.; Peel, E.; Sanchez, L.; Basei, M.

    2005-01-01

    U-Pb zircon ages between 1000 and 900 Ma corresponding to the nuclei of zircon crystals extracted from the basement of the Punta del Este Terrane (Eastern Uruguay) allowed the correlation of the protoliths of this domain with rocks attributed to the Namaqua Belt in Southwestern Africa. SHRIMP ages obtained for the ortho gneissic rocks allowed to place at ca. 750 Ma the generations of gneisses and migmatites. Differently from what occurred in Africa, reworking of this crustal segment during the Brasiliano-Pan african orogenesis was very intense, reaching the granulite facies around 640Ma. Acid volcanic and volcaniclastic rocks (Sierra de Aguirre Formation) with ages around 570 Ma, late sedimentary basins (San Carlos Formation) and post-tectonic granitoids (Santa Teresa and José Ignacio batholith s) mark the end of the events related with the Brasiliano/Pan-African orogenesis. The final collision between the Punta del Este Terrane and the western domains represented by the Dom Feliciano Belt and the Río de La Plata Craton may have occurred at around 535 Ma

  6. The Dom Feliciano belt (Brazil-Uruguay)and its fore land (Rio de la Plata Craton): framework, tectonic evolution and correlations with similar terranes of southwestern Africa

    International Nuclear Information System (INIS)

    Basei, M.; Siga, O.; Masquelin, H.; Harara, O.; Reis Neto, J.; Preciozzi, F.

    2000-01-01

    The Dom Feliciano Belt (DFB) stretches for ca. 1,200 km along southeastern Brazil and eastern Uruguay, with an average width of 150 km. From its northern limit in Santa Catarina to its termination m Uruguay, DFB is internally organized according three crustal segments characterized, from southeast to northwest, by a Granitoid belt (calci-alkaline to alkaline granitoid rocks deformed to different degrees); a Schist belt (volcano-sedimentary rocks metamorphosed from green schist to amphibolite facies), and a Fore land belt (sedimentary and anchimetamorphic volcanic rocks), the latter situated between the Schist belt and the old western terranes. Despite discontinuously covered by younger sediments, the continuity of these three segments is suggested by the similar lithotypes and structural characteristics, as well as by the gravimetric geophysical signature.In this work, DBF is interpreted as the product of successive subduction s and collisions related to the agglutination of different terranes generated or intensely reworked from the Neoproterozoic to the Cambrian, during the Brasiliano and Rio Doce orogenesis, with maximum time starting at 900 Ma (opening of the Adamastor Ocean) and ending at 530 Ma (deformation of the fore land basins) related to the tecto no-magmatic events associated with the formation of the Western Gondwana.Besides the Neoproterozoic DFB and its fore land, the Rio de la Plata Craton and the Luis Alves Microplate, constituted by Paleoproterozoic gneissic-migmatitic rocks, two other tectonic units can be recognized in southeastern Brazil and eastern Uruguay: the Sao Gabriel Block (RS) where Neoproterozoic juvenile material can be characterized in regional scale (in great part associated with an island are), and the Punta del Este Terrane, which presents, in southern Uruguay, an ortho gneiss basement with ages around 1,000 Ma and a meta sedimentary cover (Rocha Group), which can correspond in the South-American portion, to the Namaqua and Gariep

  7. Effect of chemical composition on the electrical conductivity of gneiss at high temperatures and pressures

    Directory of Open Access Journals (Sweden)

    L. Dai

    2018-03-01

    Full Text Available The electrical conductivity of gneiss samples with different chemical compositions (WA = Na2O + K2O + CaO  =  7.12, 7.27 and 7.64 % weight percent was measured using a complex impedance spectroscopic technique at 623–1073 K and 1.5 GPa and a frequency range of 10−1 to 106 Hz. Simultaneously, a pressure effect on the electrical conductivity was also determined for the WA = 7.12 % gneiss. The results indicated that the gneiss conductivities markedly increase with total alkali and calcium ion content. The sample conductivity and temperature conform to an Arrhenius relationship within a certain temperature range. The influence of pressure on gneiss conductivity is weaker than temperature, although conductivity still increases with pressure. According to various ranges of activation enthalpy (0.35–0.52 and 0.76–0.87 eV at 1.5 GPa, two main conduction mechanisms are suggested that dominate the electrical conductivity of gneiss: impurity conduction in the lower-temperature region and ionic conduction (charge carriers are K+, Na+ and Ca2+ in the higher-temperature region. The electrical conductivity of gneiss with various chemical compositions cannot be used to interpret the high conductivity anomalies in the Dabie–Sulu ultrahigh-pressure metamorphic belt. However, the conductivity–depth profiles for gneiss may provide an important constraint on the interpretation of field magnetotelluric conductivity results in the regional metamorphic belt.

  8. New radiometric ages on gneisses of the Oliverian domes in New Hampshire and Massachusetts

    International Nuclear Information System (INIS)

    Zartman, R.E.; Leo, G.W.

    1985-01-01

    Gneissic plutons of the Oliverian domes, mantled by Ammonoosuc Volcanics, are located along the axis of the Bronson Hill anticlinorium from New Hampshire to Connecticut. The contacts between the plutonic and volcanic rocks appear to be concordant on a regional scale, but gneiss intrudes the volcanics in several domes. Available radiometric and fossil evidence suggests that the Ammonoosuc Volcanics have a Middle Ordovician age but are somewhat older than the Oliverian gneisses. New U-Pb zircon data from Oliverian gneisses of six domes plot on a concordia diagram as an almost colinear array that yields an upper intercept age of about 444 m.y. The plotted data vary from nearly concordant to moderately discordant, the degree of discordance, correlating with 207 Pb/ 206 Pb ages that range from 459 to 415 m.y. The pattern of discordance does not relate to the uranium contents of the zircons nor to the geographic distribution of the domes. If 207 Pb/ 206 Pb ages are considered individually without an assumed consanguinity of the units, however, they do not find particular support in geologic relationships. Thus, they prefer the concordia intercept age of 444 +/- 8 m.y. for the suite as the best estimate for the time of crystallization of the Oliverian gneisses. Possibly, the Whitefield, Gneiss in the Jefferson dome represents a 10 to 15 m.y. older unit, although they are cautious about claiming such resolution with the present data

  9. Linking the southern West Junggar terrane to the Yili Block: Insights from the oldest accretionary complexes in West Junggar, NW China

    Science.gov (United States)

    Ren, Rong; Han, Bao-Fu; Guan, Shu-Wei; Liu, Bo; Wang, Zeng-Zhen

    2018-06-01

    West Junggar is known to tectonically correlate with East Kazakhstan; however, the tectonic link of the southern West Junggar terrane to adjacent regions still remains uncertain. Here, we examined the oldest accretionary complexes, thus constraining its tectonic evolution and link during the Early-Middle Paleozoic. They have contrasting lithologic, geochemical, and geochronological features and thus, provenances and tectonic settings. The Laba Unit was derived from the Late Ordovician-Early Devonian continental arc system (peaking at 450-420 Ma) with Precambrian substrate, which formed as early as the Early Devonian and metamorphosed during the Permian; however, the Kekeshayi Unit was accumulated in an intra-oceanic arc setting, and includes the pre-Late Silurian and Late Silurian subunits with or without Precambrian sources. Integrated with the regional data, the southern West Junggar terrane revealed a tectonic link to the northern Yili Block during the Late Silurian to Early Devonian, as suggested by the comparable Precambrian zircon age spectra between the southern West Junggar terrane and the micro-continents in the southern Kazakhstan Orocline, the proximal accumulation of the Laba Unit in the continental arc atop the Yili Block, and the sudden appearance of Precambrian zircons in the Kekeshayi Unit during the Late Silurian. This link rejects the proposals of the southern West Junggar terrane as an extension of the northern Kazakhstan Orocline and the Middle Paleozoic amalgamation of West Junggar. A new linking model is thus proposed, in which the southern West Junggar terrane first evolved individually, and then collided with the Yili Block to constitute the Kazakhstan continent during the Late Silurian. The independent and contrasting intra-oceanic and continental arcs also support the Paleozoic archipelago-type evolution of the Central Asian Orogenic Belt.

  10. Rb-Sr age estimation of granites-gneisses of Belopotokskij type (Soviet Carpathians)

    International Nuclear Information System (INIS)

    Stepanyuk, L.M.; Kotlovskaya, F.I.; Dovbush, T.I.

    1987-01-01

    Using rubidium-strontium method the age of granito-gneisses of Belopotokskij type of 470 ± 6 mln. years, which agree with isotopic age (459 ± 6 mln. years) obtained by uranium-lead isochronous method using syngenetic zircon, is established. The latter testifies to the manifestation of magmatic activity 460-470 mln. years ago. The low initial ratio of strontium isotopes 87 Sr/ 86 Sr and results of petrographic study of fel spars are indicative of magmatic nature of initial granites and plutonic (mantle or lower crust) source of magma, crystallization of which was the beginning of the Belopotokskij type granito-gneiss formation

  11. Origin and evolution of Gneiss-Charnockite rocks of Dharmapuri District, Tamil Nadu, India

    Science.gov (United States)

    Rao, D. Rameshwar; Narayana, B. L.

    1988-01-01

    A low- to high-grade transition area in Dharmapuri district was investigated petrologically and geochemically. The investigation confirmed the presence of a continuous section through a former lower crust, with felsic charnockites predominating the lower part and felsic gneisses the upper part. The structure of original gneisses is preserved in charnockites and the latter show petrographic evidence for prograde metamorphism. The prograde metamorphism is of isochemical nature as revealed by the similarity of compositions of tonalitic gneisses and tonalitic charnockites. However, the depletion of LIL elements particularly Rb, caused variation in K/Rb ratios from low values (345) in the gneisses in upper part to higher values (1775) in the charnockites in the lower crust. This variation in K/Rb ratio in a north to south traverse is related to the progressive break-down of hydrous minerals under decreasing H2O and increasing CO2 fluid conditions. Metasomatism and partial melting has also taken place to a limited extent along shear planes and weak zones. During cooling the H2O circulation affected substantial auto-regression in the transition zone resulting in the formation of second generation biotite.

  12. Geophysical constraints for terrane boundaries in southern Mongolia

    Science.gov (United States)

    Guy, Alexandra; Schulmann, Karel; Munschy, Marc; Miehe, Jean-Marc; Edel, Jean-Bernard; Lexa, Ondrej; Fairhead, Derek

    2014-05-01

    The Central Asian Orogenic Belt (CAOB) is a typical accretionary orogen divided into numerous lithostratigraphic terranes corresponding to magmatic arcs, back arcs, continental basement blocks, accretionary wedges and metamorphic blocks. These terranes should be in theory characterized by contrasting magnetic and gravity signatures thanks to their different petrophysical properties. To test this hypothesis, the stratigraphically defined terranes in southern Mongolia were compared with potential field data to constrain their boundaries and extent. The existence of terranes in southern Mongolia cannot be attested by the uniform geophysical fabrics due to the lack of systematic correspondence between the high/low amplitude and high/low frequency geophysical domains and major terranes. Processed magnetic and gravity grids show that both gravity and magnetic lineaments are E-W trending in the west and correlate with direction of some geological units. In the east, both magnetic and gravity lineaments are disrupted by NE-SW trending heterogeneities resulting in complete blurring of the geophysical pattern. Correlation of magnetic signal with geological map shows that the magnetic highs coincide with late Carboniferous-early Permian volcanic and plutonic belts. The matched-filtering shows good continuity of signal to the depth located along the boundaries of these high magnetic anomalies which may imply presence of deeply rooted tectono-magmatic zones. The axes of high density bodies in the western and central part of the studied CAOB are characterized by periodic alternations of NW-SE trending high frequency and high amplitude gravity anomalies corresponding to late Permian to Triassic cleavage fronts up to 20 km wide. The matched-filtering analysis shows that the largest deformation zones are deeply rooted down to 20 km depth. Such a gravity signal is explained by the verticalization of high density mantle and lower crustal rocks due to localized vertical shearing

  13. Comparison of Conventional, Trace Element, and Pseudosection Thermobarometry in UHP Eclogite, North Qaidam Terrane, Western China

    Science.gov (United States)

    Mattinson, C. G.; Regel, M. E.; Zhang, J.

    2014-12-01

    In the southeastern North Qaidam terrane, near Dulan, felsic host gneisses enclose minor eclogite lenses. A small (~3°C/km) increase in temperatures to the west based on Zr-in-Rt thermometry is supported by a textural trend of zoned garnet with prograde mineral inclusions in the west to unzoned garnet with only peak-stage inclusions in the east. A western eclogite sample contains minor Ep and trace Phe in addition to Grt-Omp-Qtz-Rt; a strong foliation is defined by banding of Grt and Omp. Garnet Ca falls significantly from core (Alm44Prp23Grs32) to rim (Alm48Prp27Grs23). Phengite contains 3.34-3.36 Si pfu. Conventional Grt-Omp-Phe thermobarometry yields 23-27 kbar, 660-730°C, and Zr-in-Rt thermometry yields 671 ± 9°C (n = 37). An isochemical phase diagram (pseudosection) for the system NCKFMASHO calculated with PerpleX indicates that garnet Xgrs decreases with increasing P and T, suggesting that observed garnet zoning reflects prograde growth. Garnet rim compositional isopleths intersect at 23-27 kbar, 580-620°C, depending on choice of effective bulk composition and assumed Fe3+/Fetotal. Garnet rims help define the foliation, suggesting that these P-T conditions apply to this deformation. An eastern eclogite sample contains minor Ep and abundant, coarse-grained Phe in addition to Grt-Omp-Qtz-Rt; foliation is weak. Garnet zoning is weak; compositions are Alm41-43Prp26-28Grs29-32. Phengite cores contain 3.48-3.56 Si pfu. Conventional Grt-Omp-Phe thermobarometry yields 32-36 kbar, 700-750°C, and Zr-in-Rt thermometry yields 691 ± 12°C (n = 34). Conventional thermobarometry and pseudosections yield similar peak P-T conditions, but from different mineral compositions: thermobarometry yields peak P from high-Ca Grt, but the pseudosection yields peak P from intermediate-Ca Grt; maximum Ca in Grt is predicted at lower P and T. Pseudosection-based peak Ts are significantly lower than those from Zr-in-Rt and conventional thermometry. Wide isopleth spacing in the

  14. Crustal evolution of granitoids and gneisses from the Cambaizinho belt, southern Brazil: Review zircon Pb-Pb evaporation ages and Pb-Nd-Sr isotopes

    International Nuclear Information System (INIS)

    Remus, M.V.D; Macambira, M.B; Hartmann, L.A.; Beilfuss, M

    2001-01-01

    Deformed granitoids and gneisses from the Cambai Complex (900-700 Ma) along Cambaizinho Creek and in the Vila Nova do Sul region, state of Rio Grande do Sul, Brazil, were formed in a remarkably short time, about 10 m.y., between 704±13 and 697±3 Ma. The data base of this work includes eighteen zircon Pb/Pb evaporation analyses, five Pb isotope in feldspar and whole rock. The oldest known rocks in the region are polydeformed dioritic gneisses dated by conventional U-Pb zircon at 704±13 Ma. New Pb-Pb zircon evaporation data on the late transcurrent, less deformed and more evolved granitoids (Sanga do Jobim Granitoids) yield a 697± Ma age and indicates that the evolution of the plutonic magmatism in the area was nearly contemporaneous. These data contrast with previous interpretations based on Rb-Sr data which considered that these rock associations were formed during a longer time period (700-640 Ma). All these granitoids intruded the supracrustal sequence. These granitoids yield a minimum age of about 700 Ma for the formation of the supracrustal sequence and its regional dynamothermal metamorphism. Lead isotope composition of K-feldspar from Sanga do Jobim Granitoids plot close to, but slightly below the lead isotope evolution curve of orogeny in the Zartmann and Doe model (1981). This indicates that the setting for these granitoids was that of a juvenile magmatic arc. These new data plus previous data in the region also corroborate that the crustal evolution involved juvenile crust accreted between 760-700 Ma. In contrast, the Cacapava and Sao Sepe Granites intruded the supracrustal sequences along the eastern side of the Sao Gabriel Block at 562 Ma and 550 Ma, respectively, and show Pb and Nd isotope signatures from an old basement. This evidence suggests that the juvenile terrane was thrusted over the older basement situated along the eastern part of the shield during the Dom Feliciano collisional orogeny at about 620-590 Ma (au)

  15. Geochemistry, petrography, and zircon U-Pb geochronology of Paleozoic metaigneous rocks in the Mount Veta area of east-central Alaska: implications for the evolution of the westernmost part of the Yukon-Tanana terrane

    Science.gov (United States)

    Dusel-Bacon, Cynthia; Day, Warren C.; Aleinikoff, John N.

    2013-01-01

    We report the results of new mapping, whole-rock major, minor, and trace-element geochemistry, and petrography for metaigneous rocks from the Mount Veta area in the westernmost part of the allochthonous Yukon–Tanana terrane (YTT) in east-central Alaska. These rocks include tonalitic mylonite gneiss and mafic metaigneous rocks from the Chicken metamorphic complex and the Nasina and Fortymile River assemblages. Whole-rock trace-element data from the tonalitic gneiss, whose igneous protolith was dated by SHRIMP U–Pb zircon geochronology at 332.6 ± 5.6 Ma, indicate derivation from tholeiitic arc basalt. Whole-rock analyses of the mafic rocks suggest that greenschist-facies rocks from the Chicken metamorphic complex, a mafic metavolcanic rock from the Nasina assemblage, and an amphibolite from the Fortymile River assemblage formed as island-arc tholeiite in a back-arc setting; another Nasina assemblage greenschist has MORB geochemical characteristics, and another mafic metaigneous rock from the Fortymile River assemblage has geochemical characteristics of calc-alkaline basalt. Our geochemical results imply derivation in an arc and back-arc spreading region within the allochthonous YTT crustal fragment, as previously proposed for correlative units in other parts of the terrane. We also describe the petrography and geochemistry of a newly discovered tectonic lens of Alpine-type metaharzburgite. The metaharzburgite is interpreted to be a sliver of lithospheric mantle from beneath the Seventymile ocean basin or from sub-continental mantle lithosphere of the allochthonous YTT or the western margin of Laurentia that was tectonically emplaced within crustal rocks during closure of the Seventymile ocean basin and subsequently displaced and fragmented by faults.

  16. Accretionary history of the Altai-Mongolian terrane: perspectives from granitic zircon U-Pb and Hf-isotope data

    Science.gov (United States)

    Cai, Keda; Sun, Min; Xiao, Wenjiao

    2014-05-01

    The Central Asian Orogenic Belt (CAOB) consists of many tectonic terranes with distinct origin and complicated evolutionary history. Understanding of individual block is crucial to reconstruct the geodynamic history of the gigantic accetionary collage. This study presents zircon U-Pb ages and Hf isotopes for the granitoid rocks in the Russian Altai mountain range (including Gorny Altai, Altai-Mongolian terrane and CTUS suture zone between them), in order to clarify the timing of granitic magmatism, source nature, continental crustal growth and tectonic evolution. Our dating results suggest that granitic magmatism of the Russian Altai mountain range occurred in three major episodes including 445~429 Ma, 410~360 Ma and ~241 Ma. Most of the zircons within the Paleozoic granitoids present comparable positive ɛHf(t) values and Neoproterozoic crustal model ages, which favor the interpretation that the juvenile crustal materials produced in the early stage of CAOB were probably dominant sources for the Paleozoic magmatism in the region. The inference is also supported by widespread occurrence of short-lived juvenile materials including ophiolites, seamount relics and arc assemblages in the north CAOB. Consequently, the Paleozoic massive granitic rocks maybe not represent continental crustal growth at the time when they were emplaced, but rather record reworking of relatively juvenile Proterozoic crustal rocks although mantle-derived mafic magma was possibly involved to sever as heat engine during granitic magma generation. The Early Triassic granitic intrusion may be product in an intra-plate environment, as the case of same type rocks in the adjacent areas. The positive ɛHf(t) values (1.81~7.47) and corresponding Hf model ages (0.80~1.16 Ga) together with evidence of petrology are consistent with the interpretation that the parental magma of the Triassic granitic intrusion was produced from enriched mantle-derived sources under an usually high temperature condition

  17. Terrane-Scale Metastability in Subducted Himalayan Continental Crust as Revealed by Integrated Petrological and Geodynamic Modeling

    Science.gov (United States)

    Palin, R. M.; Reuber, G. S.; White, R. W.; Kaus, B. J. P.; Weller, O. M.

    2017-12-01

    The Tso Morari massif, northwest India, is one of only two regions in the Himalayan Range that exposes subduction-related ultrahigh-pressure (UHP) metamorphic rocks. The tectonic evolution of the massif is strongly debated, however, as reported pressure estimates for peak metamorphism range between 2.4 GPa and 4.8 GPa. Such ambiguity hinders effective lithospheric-scale modeling of the early stages of the orogen's evolution. We present the results of integrated petrological and geodynamic modeling (Palin et al., 2017, EPSL) that provide new quantitative constraints on the prograde-to-peak pressure-temperature-time (P-T-t) path, and predict the parageneses that felsic and mafic components of the massif crust should have formed under equilibrium conditions. Our model shows that peak P-T conditions of 2.6-2.8 GPa and 600-620 °C, representative of subduction to 90-100 km depth (assuming lithostatic pressure), were reached just 3 Myr after the onset of collision. These P-T-t constraints correlate well with those reported for similar UHP eclogite in the along-strike Kaghan Valley, Pakistan, suggesting that the northwest Himalaya contains dismembered remnants of a 400-km long UHP terrane comparable in size to the Western Gneiss Region, Norway, and the Dabie-Sulu belt, China. The extremely high pressures (up to 4.8 GPa) for peak metamorphism reported by some workers are likely to be unreliable due to thermobarometry having been performed on minerals that did not represent equilibrium assemblages. Furthermore, key high-P minerals predicted to form in subducted Tso Morari continental crust (e.g. jadeite, Mg-rich garnet) are absent from natural samples in the region, reflecting the widespread metastable preservation of lower-pressure protolith assemblages during subduction and exhumation. This result questions the reliability of geodynamic simulations of orogenesis that are commonly predicated on equilibrium metamorphism operating continuously throughout tectonic cycles.

  18. Gneiss Macuira: tectonic evolution of Paleozoic metamorphic rocks of the Alta Guajira, Colombia

    International Nuclear Information System (INIS)

    Lopez I; A Julian; Zuluaga C; A, Carlos

    2012-01-01

    The Macuira Gneiss is a Paleozoic metamorphic unit that outcrops in the Simarua, Jarara and Macuira ranges, Alta Guajira. It is composed by a lithologies metamorphosed under amphibolite facies P-T conditions and consist of amphibolitic and quartz feldspathic gneisses, amphibolites, schists, pegmatites, calc-silicated rocks and marbles, with migmatization evidences in gneisses and amphibolites. Five foliations (S1-5) and three folding events (F1-3) were identified and interpreted as product of two metamorphic events, developed in a progressive barrovian metamorphic gradient of intermediate pressure with intermediate P-T ratio, interpreted as product of continental collision tectonics. This unit is important in understanding of the tectonic evolution of the Alta Guajira and Caribbean because it records different deformational phases pre-, syn- and post-migmatitic, that could be related with different tectonic episodes: the first associated with the collision between Laurasia and Gondwana (Alleghanian Orogeny - Late Paleozoic), and the second related with the Caribbean Plate evolution (Andean Orogeny - Meso-Cenozoic).

  19. Polycyclic migmatites from southern of Minas Gerais state and adjacent parts: structural/petrographic characterization and geochronological data

    International Nuclear Information System (INIS)

    Artur, A.C.; Wernick, E.; Kawashita, K.

    1990-01-01

    The geology of the southern part of the State of Minas Gerais and adjacent parts of the State of Sao Paulo (SE Brazil) is built up by gray gneisses (Barbacena and Amparo Complexes), pink gneisses (Pinhal Complex) and granulites (Guaxupe Complex) areas, the oldest of them of Archaean ages. Structural, petrographic, geochronological and geologic data indicate that in fact each of those complexes is the result of a long evolution including successive phases of deformation, anatexis and intrusions. The extensive migmatization of the Archaean rocks during the Lower and Upper Proterozoic combined with the intrusion of huge granitoid bodies suggest that the considered region has been involved in successively continental approaches by subduction/collision processes. (author)

  20. Preferential rifting of continents - A source of displaced terranes

    Science.gov (United States)

    Vink, G. E.; Morgan, W. J.; Zhao, W.-L.

    1984-01-01

    Lithospheric rifting, while prevalent in the continents, rarely occurs in oceanic regions. To explain this preferential rifting of continents, the total strength of different lithospheres is compared by integrating the limits of lithospheric stress with depth. Comparisons of total strength indicate that continental lithosphere is weaker than oceanic lithosphere by about a factor of three. Also, a thickened crust can halve the total strength of normal continental lithosphere. Because the weakest area acts as a stress guide, any rifting close to an ocean-continent boundary would prefer a continental pathway. This results in the formation of small continental fragments or microplates that, once accreted back to a continent during subduction, are seen as displaced terranes. In addition, the large crustal thicknesses associated with suture zones would make such areas likely locations for future rifting episodes. This results in the tendency of new oceans to open along the suture where a former ocean had closed.

  1. Partial melting of UHP calc-gneiss from the Dabie Mountains

    Science.gov (United States)

    Liu, Penglei; Wu, Yao; Liu, Qiang; Zhang, Junfeng; Zhang, Li; Jin, Zhenmin

    2014-04-01

    Exhumation melting has been proposed for the ultra-high pressure (UHP) metamorphic rocks in the Dabie Mountains based on melting experiments. We document here the first petrological and mineralogical evidence demonstrating that the UHP calc-gneisses from the Ganjialing area in the Dabie Mountains experienced partial melting during early exhumation. The assemblage of garnet, phengite (Si = 3.65 pfu), coesite, rutile and carbonate preserved in the calc-gneisses indicates a peak metamorphic condition of 692-757 °C and 4.0-4.8 GPa. Partial melting is indicated by several lines of evidence: the melting textures of phengite, the feldspar-dominated films, bands, branches, blebs and veins, the euhedral K-feldspars, the intergrowth film of plagioclase and K-feldspar, the plagioclase + biotite intergrowth after garnet and the epidote poikiloblasts. Polyphase inclusions in garnet are characterized with wedge-like offshoots and serrate outlines whereas those in epidote display negative crystal shapes, which can be best interpreted by entrapment of former melts. We propose a wet melting reaction of Phn + Q ± Na-Cpx + H2O = Bt + Pl + Grt + felsic melts, which likely took place at ca.650-800 °C and ca.1.0-2.0 GPa, to interpret the melting event in the calc-gneisses. Chemical exchanges between garnet and melts produced new garnet domains with higher almandine, spessartine, MREE, HREE and Y but lower grossular, pyrope, P, Sc, Ti, V and Zr contents. Zr-in-rutile thermometer reveals a low temperature of 620-643 °C at 5 GPa, indicating a later reset for Zr in rutile. Healed fractures are suggested to be responsible for the formation of some polyphase inclusions in garnet.

  2. Thrust tectonics in crystalline domains: The origin of a gneiss dome

    Science.gov (United States)

    Greiling, R. O.

    1997-12-01

    Structural geological field work, microscopic and magnetic fabric studies have been applied in order to assess the structural origin of a gneiss dome, based on a regional example from the Neoproterozoic Pan-African Belt of NE Africa, the Wadi Hafafit Culmination (WHC). The culmination is dominated by a number of major shear zones, which form both the boundaries between the gneissic core and surrounding low grade successions as well as those of minor structural units within the gneisses. These shear zones form a linked fault system, which, based on shear criteria, fault-bend fold and overall geometric interrelationships, can be classified as an antiformal stack. The relative age sequence of the shear zones/thrusts with the highest thrust oldest and the lowermost youngest points to a forward-propagating thrust system. This, together with the shear criteria, exclude an origin of the WHC as a metamorphic core complex, where the highest shear zone should be youngest. The geometry of the WHC antiformal stack is documented by maps and sections as well as section balancing and restoration. Microscopic work showed brittle deformation in feldspar and dynamic recrystallization in quartz ribbons. The asymmetry of the fabric confirmed the macroscopically determined shear sense. However, there is one example of an earlier, perhaps extensional shear movement. Mylonitic foliation and transport-parallel lineation have also been determined by magnetic fabric studies. The observations suggest that thrusts may cut across both previously folded crystalline rocks as well as homogeneous granitoid plutonic bodies. According to the regional tectonic picture the large-scale structure of the gneiss dome originated after a phase of (late-orogenic) extensional collapse. It is speculated that during late-orogenic cooling the upper part of the lithosphere was sufficiently strong to allow brittle thrusting whilst the lithosphere as a whole was still weak enough to allow large-scale compressional

  3. Metamorphic history and age of aluminous gneisses of the Belomorian belt of the Baltic shield

    International Nuclear Information System (INIS)

    Bibikova, E.V.; Borisova, E.Yu.; Makarov, V.A.; Drugova, G.M.

    1997-01-01

    Metamorphic conditions and age are determined for the early metamorphic stage of aluminous gneisses in the Chupa nappe in the Belomorian Mobile Belt. The granulite-facies metamorphic conditions during Late Archean time are determined based on the composition of garnet and biotie from the metapelites. The early metamorphic stage was dated at 2860 ± 30 Ma based on the U-Pb systematics of granulitic zircon from the metapelites. The U-Pb isotopic system of the zircon was strongly affected by Svecogennian metamorphism (at 1750 Ma). The geodynamic evolution of the Belomorian Mobile Belt is discussed in light of the data of this work

  4. Preliminary radiometric analyses of zircons from the Mount Copeland syenite gneiss, Shuswap metamorphic complex, British Columbia

    International Nuclear Information System (INIS)

    Okulitch, A.V.; Laveridge, W.D.; Sullivan, R.W.

    1981-01-01

    The isotopic ratios resulting from Pb and U analyses on three zircon fractions from syenite gneiss intrusive into metasediments of the Shuswap Metamorphic Complex are collinear on a concordia plot and yield upper and lower intercepts of about 773 Ma and 70 Ma. The upper intercept is tentatively interpreted as the minimum age of emplacement. The lower intercept is suggested to be the time of uplift and cooling associated with tectonic denudation of the Shuswap Complex. The implied age of the country rocks is pre-late Proterozoic and they may be correlatives of the Purcell Supergroup. (auth)

  5. Geochemistry of mylonitic tourmaline-bearing granite- gneiss pluton in the northeast of June mine

    Directory of Open Access Journals (Sweden)

    Arezoo Moradi

    2017-07-01

    Full Text Available Introduction Studied mylonitic granite-gneiss body is located in the Northwest of the Azna region in the Lorestan province close to the June dimension stone mine. It is a part of the metamorphic- magmatic complex including granite-gneiss, amphibolite, marble and schist. The crystalline basement is attributed to late-Neoproterozoic and it indicates a Panafrican basement, which yields a laser-ablation ICP–MS U–Pb zircon ages of 608 ± 18 Ma and 588 ± 41 Ma (Shakerardakani et al., 2015. There are two granite-gneiss plutons in the complex that are Galeh– Dezh (Shabanian et al., 2009, and June plutons. The Galeh-Doz pluton are previously proposed as syn-deformation pluton with a major S-shaped bend which has been imparted during dextral shearing with a Late Cretaceous (Mohajjel and Fergusson, 2000. However, new age dating on the pluton using U–Pb in the magmatic zircon produced the late-Neoproterozoic dates (Nutman et al., 2014; Shakerardakani et al., 2015. The granite-gneiss plutons show mylonitic fabrics and microstructures (Shabanian et al., 2010. The geochemical characteristics of mylonitic granite-gneiss body near June mine in NW Azna, is in the focus of our research. Materials and methods Petrographic investigations of 30 thin sections were made. Then eight samples were selected and analyzed for whole rock major, trace and REE compositions by ICP-emission spectrometry and ICP-mass spectrometry using natural rock standards as reference samples for calibration at the ACME Analytical Laboratories in Vancouver, British Columbia, Canada. Results The studied gneiss- granitic body has lepido-granoblastic texture as its major texture. It variably shows evidence of dynamic deformation from ultramylonite to protomylonite. The gneiss- granite consists of quartz, alkali feldspar (mostly as perthite, plagioclase, biotite, white mica (muscovite and phengitic muscovite. Accessory phases in the granitoid include, tourmaline, zircon, magmatic epidote

  6. Summary report - development of laboratory tests and the stress- strain behaviour of Olkiluoto mica gneiss

    Energy Technology Data Exchange (ETDEWEB)

    Hakala, M.; Heikkilae, E. [Helsinki Univ. of Technology, Espoo (Finland). Lab. of Rock Engineering

    1997-05-01

    This work summarizes the project aimed at developing and qualifying a suitable combination of laboratory tests to establish a statistically reliable stress-strain behaviour of the main rock types at Posiva Oy`s detailed investigation sites for disposal of spent nuclear fuel. The work includes literature study of stress-strain behaviour of brittle rock, development and qualification of laboratory tests, suggested test procedures and interpretation methods and finally testing of Olkiluoto mica gneiss. The Olkiluoto study includes over 130 loading tests. Besides the commonly used laboratory tests, direct tensile tests, damage controlled tests and acoustic emission measurements were also carried out. (orig.) (54 refs.).

  7. Summary report - development of laboratory tests and the stress- strain behaviour of Olkiluoto mica gneiss

    International Nuclear Information System (INIS)

    Hakala, M.; Heikkilae, E.

    1997-05-01

    This work summarizes the project aimed at developing and qualifying a suitable combination of laboratory tests to establish a statistically reliable stress-strain behaviour of the main rock types at Posiva Oy's detailed investigation sites for disposal of spent nuclear fuel. The work includes literature study of stress-strain behaviour of brittle rock, development and qualification of laboratory tests, suggested test procedures and interpretation methods and finally testing of Olkiluoto mica gneiss. The Olkiluoto study includes over 130 loading tests. Besides the commonly used laboratory tests, direct tensile tests, damage controlled tests and acoustic emission measurements were also carried out. (orig.) (54 refs.)

  8. New Rb-Sr isotopic ages and geochemistry of granitic gneisses from southern Bastar: implications for crustal evolution

    International Nuclear Information System (INIS)

    Sarkar, G.; Gupta, S.N.; Bishui, P.K.

    1994-01-01

    Deformed gneisses from the southern Bastar craton yield Rb-Sr whole-rock ages of 2560 Ma and 2659 Ma with initial Sr ratios ranging between 0.70899 and 0.70726 respectively. The isotopic data are found to be scattered even at the outcrop scale which possibly indicate large-scale reworking of the gneisses during the period. The high initial Sr ratios that associate with scattering of the isotopic data reflect reworking of older gneisses. Geochemically, these gneisses are considered to be derived from an amphibolitic or basaltic protolith. The 2095 Ma (initial Sr ratio of 0.74312) old leucocratic granite intrusive into these gneisses represent early Proterozoic magmatic activity. Based on the available isotopic and geochemical data, it is suggested that the Bastar craton represents a polyphase, multicomponent terrain developed by repeated magmatism at a much earlier, probably during mid-Archaean, time and was extensively reworked during the time span between end-Archaean and early Proterozoic period. This reworking may be synchronous with coalescing of smaller crustal components possibly during the end-Archaean time. (author). 21 refs., 5 figs., 2 tabs

  9. Far-travelled permian chert of the North Fork terrane, Klamath mountains, California

    Science.gov (United States)

    Mankinen, E.A.; Irwin, W.P.; Blome, C.D.

    1996-01-01

    Permian chert in the North Fork terrane and correlative rocks of the Klamath Mountains province has a remanent magnetization that is prefolding and presumably primary. Paleomagnetic results indicate that the chert formed at a paleolatitude of 8.6?? ?? 2.5?? but in which hemisphere remains uncertain. This finding requires that these rocks have undergone at least 8.6?? ?? 4.4?? of northward transport relative to Permian North America since their deposition. Paleontological evidence suggests that the Permian limestone of the Eastern Klamath terrane originated thousands of kilometers distant from North America. The limestone of the North Fork terrane may have formed at a similar or even greater distance as suggested by its faunal affinity to the Eastern Klamath terrane and more westerly position. Available evidence indicates that convergence of the North Fork and composite Central Metamorphic-Eastern Klamath terranes occurred during Triassic or Early Jurassic time and that their joining together was a Middle Jurassic event. Primary and secondary magnetizations indicate that the new composite terrane containing these and other rocks of the Western Paleozoic and Triassic belt behaved as a single rigid block that has been latitudinally concordant with the North American craton since Middle Jurassic time.

  10. Stable Isotope Evidence for a Complex Fluid Evolution of the Northwestern British Columbia Coast Ranges Related to Terrane Accretion

    Science.gov (United States)

    Moertle, J.; Holk, G. J.

    2015-12-01

    Stable isotope geochemistry reveals a complex fluid evolution for the Western Metamorphic Belt (WMB), Coast Ranges Batholith (CRB), Central Gneiss Complex (CGC) and Coast Ranges Megalineament (CRM). These fluids are a product of a complex tectonic history related to terrane accretion that includes oblique convergence, metamorphism, magmatism, and orogenic collapse. From W-to-E, these fluid systems are as follows. High-pressure greenschist-to-amphibolite facies metasedimentary rocks of the WMB record variable mineral δD (-61 to -104‰) and δ18O (e.g., quartz +9.6 to +13.4‰) values with multiple minerals in apparent isotopic equilibrium (T ~ 450-550°C) suggest a low W/R system dominated by metamorphic fluids. Variable and non-equilibrium δD (-53 to -143‰) and δ18O (e.g., biotite +2.3 to +5.3‰) values from diorites of the Quottoon pluton affected by the ductile CRM suggest a complex evolution that involved both metamorphic and meteoric-hydrothermal fluids in this dextral shear zone; these results differ from those 300 km along strike to the north that documented only metamorphic fluids in the CRM (Goldfarb et al., 1988). Our data and those of Magaritz and Taylor (1976) from granulite facies metasediments of the CGC and plutons of the western CRB reveal homogeneous δD values (-62 to -78‰) and a restricted range of δ18O values (e.g., quartz +8.5 to +11.5‰) with all minerals in equilibrium at T > 570°C indicate a system dominated by magmatic fluids. Calculated whole-rock δ18O values (~ +7‰) for the Quottoon pluton and CRB intrusive rocks suggest a mantle origin for these magmas. Reinterpretation of very low δD (< -150‰) and quartz-feldspar δ18O pairs that display extreme disequilibrium (feldspar δ18O values as low as -5‰) from the Ponder pluton, eastern CRB, and Hazelton Group point reveals that the major meteoric-hydrothermal system that affected these rocks was related to Eocene detachment faulting along the Shames Lake fault system, a

  11. The Punta del Este Suspect Terrane: a possible counterpart in Eastern Uruguay of the Namaqua Complex and Gariep Belt in Western Africa

    International Nuclear Information System (INIS)

    Preciozzi, F.; Basei, M.; Peel, E.

    2005-01-01

    The geology of the southwestern extreme of the African continent is characterised by a series of mobile belts that delimit the western margin of the block constituted by the Kalahari-Kapvaal cratons. In this context, Panafrican belts predominate, represented in the north-northwestern portion by the Damara, in the western region by the Gariep and, in the southern region by the Saldania. These belts, of Neoproterozoic-Eopaleozoic ages predominantly expose sedimentary covers metamorphosed in the greenschist facies. In the northwestern portion of South Africa and south of Namibia, of major interest for the correlation intended in this work. The basement of the Panafrican cover, in this case the Gariep Group, is largely constituted by medium- to high-grade terranes generated during the Kibarian event (1.2-1.1Ga) responsible for the formation of igneous and metamorphic rocks and attributed to the Metamorphic Namaqua-Natal Complex (Frimmel, 1995). This Complex presents low-pressure granulite facies conditions (Clifford et al., 1981) with polymetamorphic evolution, where old nuclei of Paleoproterozoic age (1800-2000Ma) occur within the terranes generated during the Kibarian orogeny. U-Pb studies in zircons by SHRIMP (Robb et al., 1998) confirmed for Namaqua two rock-generating events with pulses between 1220-1170 Ma (Kibarian) and 1060-1030Ma (Namaqua); with the latter the third regional deformation and important magmatism phases would be associated. In this period granulitic metamorphism and intrusion of granitoids 2 occurred and are presently represented by the Nababeep and Modderfontein gneisses that are cut by the Concordia and Rietberg granitoids. The Panafrican superposition is registered predominantly along the coastal region. The Gariep Group occurs along the coastal region tectonically covering the terranes associated with the Namaqua Metamorphic Complex. It is characterised by a group constituted mainly by rocks of very low to low metamorphic grade distributed in

  12. REE distributions in a high-grade Archaean gneiss complex in Scotland: Implications for the genesis of ancient sialic crust

    International Nuclear Information System (INIS)

    Drury, S.A.

    1978-01-01

    Seventeen rocks from the Lewisian Gneiss of the Inner Hebrides of Scotland, which represent three distinct lithological types at granulite to greenschist facies of metamorphism show rare-earth element patterns which seem not to have been disturbed by their complex metamorphic history. Some indication of their origin can be obtained by simple geochemical models. (Auth.)

  13. Scandian Ultrahigh-Pressure Metamorphism of Proterozoic Basement Rocks on Fjortoft and Otroy, Western Gneiss Region, Norway

    NARCIS (Netherlands)

    Carswell, D.A.; van Roermund, H.L.M.; Wiggers de Vries, D.F.

    2006-01-01

    Electron microprobe mineral composition data are presented for samples of exsolved and recrystallized garnet websterites within the mantle-derived peridotite bodies and of external orthopyroxene eclogite lenses directly enclosed within the gneisses on the islands of Fjørtoft and Otrøy in the Western

  14. Cebollati group, Nico Perez terrane: Definition and age

    International Nuclear Information System (INIS)

    Gaucher, C; Chemale, F.; Bossi, J.; Castiglioni, E.; Castiglioni, E.

    2010-01-01

    The Cebollati Group (Nico Perez Terrane) is formally erected in this work to include a meta sedimentary succession informally known as L as Teta s Complex . It is shown that the stratigraphy of the unit can be reconstructed at a number of sections between Minas and Zapicìn, using sedimentary structures and stromatolites as geo petal indicators. The basement of the group is represented by metamorphic rocks and granitoids of the La China Complex, for which a new U-Pb zircon age of 3.029 ± 54 Ma is presented. The Cebollatií Group comprises, from base to top, three formations: the Arroyo Ma lo Formation (sandstones and petites), Cerro de Valuable Formation (dolostones, partly stromatolitic, and p elites) and the Cerro del Diamant e Formation (p elites, BIF, quartz-pebble conglomerates and sandstones). The mean thickness of the Cebollatií Group is ca. 2 km, being greatest in the south and diminishing to the north. Available ages for the unit suggested a Neoarchean depositional age of 2.75 Ga. However, in this work 12 Nd model ages are presented for sedimentary rocks of the Cebollatí Group, which are mostly younger than 2.75 Ga, the youngest being 1.64 Ga. These ages call into question the Neoarchean age accepted for the unit, suggesting a Meso proterozoic depositional age. The evidence supporting both views is discussed in view of the new data. The minimum age of the Cebollatí Group is 1.3 Ga on the basis of carbon isotope ratios of dolostones and deformational ages consistently around 1.25 Ga

  15. Grenvillean sutures zones in the northern portion of the Cuyania terrane, Republica Argentina. geophysical evidence

    International Nuclear Information System (INIS)

    Chernicoff, C.; Vujovich, G.

    2004-01-01

    In the northern portion of the Cuyania terrane there is geophysical evidence for the ocurrence of two ancient WNW suture zones, corresponding to the Guandacol and Vinchina lineaments. The location of these sutures is consistent with analogous structures in Laurentia, in the Ouachita embayment region, where the Grenvillean orogen trends WNW. It is argued that the WNW transform faults pertaining to the Ouachita rift would have developed as a result of a reactivation of compressional structures of identical orientation associated to the accretion of Grenvillean terranes. The Guandacol and Vinchina lineaments would have been in physical continuity with analogous megastructures in the Ouachita embayment region, and they both would have originated as compressional structures, later reactivated as transcurrent fault zones during the late Proterozoic early Paleozoic. The interpretation of the Guandacol and Vinchina lineaments as Grenvillean suture zones would add more complexity to the Cuyania terrane, with respect to what has been described up to now; they could precede the amalgamation of the Pie de Palo and Precordillera terranes (constituents of the Cuyania composite terrane) [es

  16. The Khida terrane - Geology of Paleoproterozoic rocks in the Muhayil area, eastern Arabian Shield, Saudi Arabia

    Science.gov (United States)

    Stoeser, D.B.; Whitehouse, M.J.; Stacey, J.S.

    2001-01-01

    The bulk of the Arabian Shield of Saudi Arabia is underlain by Neoproterozoic terranes of oceanic affinity that were accreted during Pan-African time (about 680- 640Ma). Geologicalmappingandisotopicinvestigations during the 1980’s,however, provided the first evidence for Paleoproterozoic continental crust within the east- central part of the shield in Saudi Arabia. These studies delineated an older basement domain, herein referred to as the Khida terrane (Fig. l), which is defined as that part of the southern Afif composite terrane underlain by Paleoproterozoicto Archean continental crust (Stoeser and Stacey, 1988). The isotopic and geochronologic work to support our current studies within the Khida terrane are discussed in a companion abstract (Whitehouse et al., this volume). The regional geology and geochronology of the region has been summarized in detail by Johnson (1996). The current study is based on the continued use of samples previously collected in the Khida area by the authors and others as well as new field work conducted by us in 1999. This work further defines the occurrence of late Paleoproterozoic rocks at Jabal Muhayil, which is located at the eastern margin of the exposed terrane (Fig. 1). Our isotopic work is at an early stage and this abstract partly relates geologic problems that remain to be resolved. 

  17. The Athabasca Granulite Terrane and Evidence for Dynamic Behavior of Lower Continental Crust

    Science.gov (United States)

    Dumond, Gregory; Williams, Michael L.; Regan, Sean P.

    2018-05-01

    Deeply exhumed granulite terranes have long been considered nonrepresentative of lower continental crust largely because their bulk compositions do not match the lower crustal xenolith record. A paradigm shift in our understanding of deep crust has since occurred with new evidence for a more felsic and compositionally heterogeneous lower crust than previously recognized. The >20,000-km2 Athabasca granulite terrane locally provides a >700-Myr-old window into this type of lower crust, prior to being exhumed and uplifted to the surface between 1.9 and 1.7 Ga. We review over 20 years of research on this terrane with an emphasis on what these findings may tell us about the origin and behavior of lower continental crust, in general, in addition to placing constraints on the tectonic evolution of the western Canadian Shield between 2.6 and 1.7 Ga. The results reveal a dynamic lower continental crust that evolved compositionally and rheologically with time.

  18. Relationships between the Brook Street Terrane and Median Tectonic Zone (Median Batholith) : evidence from Jurassic conglomerates

    International Nuclear Information System (INIS)

    Tulloch, A.J.; Kimbrough, D.L.; Landis, C.A.; Mortimer, N.; Johnston, M.R.

    1999-01-01

    U-Pb zircon ages of 237-180 Ma and c. 280 Ma of seven granitoid clasts from the Rainy River Conglomerate which lies within the eastern Median Tectonic Zone (Median Batholith) in Nelson, and the Barretts Formation of the Brook Street Terrane in Southland, constrain the depositional ages of both units to be no older than c. 180-200 Ma (Early Jurassic). The minimum age of the Rainy River Conglomerate is constrained by the 147 +2 -1 Ma (Latest Jurassic) emplacement age of the One Mile Gabbronorite (new name: previously western Buller Diorite). The ages and chemistry of five of the granitoid clasts are broadly compatible with derivation from rocks that are now represented by Triassic plutons of the Median Tectonic Zone (Median Batholith), although ages as young as 180 Ma are slightly outside the range of the latter as currently exposed in New Zealand. The age (273-290 Ma, 237 +/- 3 Ma) and chemistry of the other two clasts (one each from Rainy River Conglomerate and Barretts Formation) suggest derivation from the Brook Street Terrane. Similarity in stratigraphic age, depositional characteristics, granitoid clast ages and composition between Rainy River Conglomerate and Barretts Formation suggests that they are broadly correlative and collectively overlapped a combined Brook Street Terrane - Median Batholith (MTZ) before the Late Jurassic (147 +2 -1 Ma). Sedimentary overlap may also have continued across to Middle Jurassic conglomeratic strata in the Murihiku Terrane to the east of the Brook Street Terrane. A U-Pb zircon age of 261 +/- 2 Ma is reported for Pourakino Trondhjemite of the Brook Street Terrane. (author). 56 refs., 10 figs., 4 tabs

  19. Grain-scale Sr isotope heterogeneity in amphibolite (retrograded UHP eclogite, Dabie terrane): Implications for the origin and flow behavior of retrograde fluids during slab exhumation

    Science.gov (United States)

    Guo, Shun; Yang, Yueheng; Chen, Yi; Su, Bin; Gao, Yijie; Zhang, Lingmin; Liu, Jingbo; Mao, Qian

    2016-12-01

    To constrain the origin and flow behavior of amphibolite-facies retrograde fluids during slab exhumation, we investigate the textures, trace element contents, and in situ strontium (Sr) isotopic compositions (using LA-MC-ICP-MS) of multiple types of epidote and apatite in the UHP eclogite and amphibolites from the Hualiangting area (Dabie terrane, China). The UHP epidote porphyroblasts in the eclogite (Ep-E), which formed at 28-30 kbar and 660-720 °C, contain high amounts of Sr, Pb, Th, Ba, and light rare earth elements (LREEs) and have a narrow range of initial 87Sr/86Sr ratios (0.70431 ± 0.00012 to 0.70454 ± 0.00010). Two types of amphibolite-facies epidote were recognized in the amphibolites. The first type of epidote (Ep-AI) developed in all the amphibolites and has slightly lower trace element contents than Ep-E. The Ep-AI has a same initial 87Sr/86Sr ratio range as the Ep-E and represents the primary amphibolite-facies retrograde product that is associated with an internally buffered fluid at 8.0-10.3 kbar and 646-674 °C. The other type of epidote (Ep-AII) occurs as irregular fragments, veins/veinlets, or reaction rims on the Ep-AI in certain amphibolites. Elemental X-ray maps reveal the presence of Ep-AI relics in the Ep-AII domains (appearing as a patchy texture), which indicates that Ep-AII most likely formed by the partial replacement of the Ep-AI in the presence of an infiltrating fluid. The distinctly lower trace element contents of Ep-AII are ascribed to element scavenging by a mechanism of dissolution-transport-precipitation during replacement. The Ep-AII in an individual amphibolite exhibits large intra- and inter-grain variations in the initial 87Sr/86Sr ratios (0.70493 ± 0.00030 to 0.70907 ± 0.00022), which are between those of the Ep-AI and granitic gneisses (wall rock of the amphibolites, 0.7097-0.7108). These results verify that the infiltrating fluid was externally derived from granitic gneisses. The matrix apatite in the amphibolites has

  20. Characteristics and mode of emplacement of gneiss domes and plutonic domes in central-eastern Pyrenees

    Science.gov (United States)

    Soula, Jean-Claude

    Gneiss domes and plutonic granitoid domes make up almost 50% of the pre-Hercynian terrains in the Central and Eastern Pyrenees. From a structural study of the shape and internal structure of the domes and of their relationships with the enclosing rocks, it can be shown that both types of domes were emplaced diapirically during the major regional deformation phase and the peak of regional metamorphism. The study also shows that the internal structure, the overall shape and general behaviour relative to the host rocks are similar for plutonic domes and for gneiss domes. This appears to be in good agreement with H. Ramberg's (1967, Gravity Deformation and the Earth's Crust. Academic Press, London; 1970, Model studies in relation to intrusion of plutonic bodies. In: Mechanisms of Igneous Intrusion (edited by Newall, G. & Rast, N.) Geol. J. Spec. Issue2, 261-286.) model studies showing that dome or mushroom-like structures, similar to those observed, develop when there is a small viscosity ratio between the rising body and its enclosing medium. This implies a high crystal content for the granitoid magma. This crystal content has been estimated by (i) calculating the viscosity and density in natural conditions from petrological data for the magma considered as a suspension, using the model and program of J. P. Carron et al. (1978 Bull Soc. géol. Fr.20, 739-744.); (ii) using the recent results of experimental deformation of partially melted granites of I. van der Molen & M. S. Paterson (1979, Contr. Miner. Petrol.70, 299-318.) and (ii) comparing the preceding results with the data obtained by deformation experiments on rocks similar to those enclosing the domes. The minimum crystal content for the development of a dome-like structure has been, thus, estimated to about 70%, i.e. a value very close to that estimated by van der Molen & Paterson (1979) to be the critical value separating the granular framework flow from suspension-like behaviour. The effect of small

  1. Long-range laser scanning and 3D imaging for the Gneiss quarries survey

    Science.gov (United States)

    Schenker, Filippo Luca; Spataro, Alessio; Pozzoni, Maurizio; Ambrosi, Christian; Cannata, Massimiliano; Günther, Felix; Corboud, Federico

    2016-04-01

    In Canton Ticino (Southern Switzerland), the exploitation of natural stone, mostly gneisses, is an important activity of valley's economies. Nowadays, these economic activities are menaced by (i) the exploitation costs related to geological phenomena such as fractures, faults and heterogeneous rocks that hinder the processing of the stone product, (ii) continuously changing demand because of the evolving natural stone fashion and (iii) increasing administrative limits and rules acting to protect the environment. Therefore, the sustainable development of the sector for the next decades needs new and effective strategies to regulate and plan the quarries. A fundamental step in this process is the building of a 3D geological model of the quarries to constrain the volume of commercial natural stone and the volume of waste. In this context, we conducted Terrestrial Laser Scanning surveys of the quarries in the Maggia Valley to obtain a detailed 3D topography onto which the geological units were mapped. The topographic 3D model was obtained with a long-range laser scanning Riegl VZ4000 that can measure from up to 4 km of distance with a speed of 147,000 points per second. It operates with the new V-line technology, which defines the surface relief by sensing differentiated signals (echoes), even in the presence of obstacles such as vegetation. Depending on the esthetics of the gneisses, we defined seven types of natural stones that, together with faults and joints, were mapped onto the 3D models of the exploitation sites. According to the orientation of the geological limits and structures, we projected the different rock units and fractures into the excavation front. This way, we obtained a 3D geological model from which we can quantitatively estimate the volume of the seven different natural stones (with different commercial value) and waste (with low commercial value). To verify the 3D geological models and to quantify exploited rock and waste volumes the same

  2. Chronologic constraints on the tectonic evolution of the Wilson Lake terrane of the Grenville Province, Canada

    DEFF Research Database (Denmark)

    Reno II, Barry Len; Korhonen, F.J.; Stout, J.H.

    the Grenville Orogen in North America. Many of these terranes record evidence of two orogenies: the Labradorian Orogeny at ca. 1710-1600 Ma, and the Grenville Orogeny at ca. 1080-980 Ma. The rocks in the Wilson Lake terrane are interpreted to have been subjected to peak pressures of ~0.95 GPa......) monazite exhibits distinct core and rim zoning in yttrium X-ray compositional maps, and occurs predominately in the melanosome of the rocks, and 2) a population of smaller (up to ~50 µm) unzoned monazite rarely occurs in quartz-rich layers of the rocks. In a majority of the melanosome-hosted monazite, (U...

  3. Factor value determination and applicability evaluation of universal soil loss equation in granite gneiss region

    Directory of Open Access Journals (Sweden)

    Wen-hai Zhang

    2009-06-01

    Full Text Available Six types of runoff plots were set up and an experimental study was carried out to examine natural rate of soil and water loss in the granite gneiss region of northern Jiangsu Province in China. Through correlation analysis of runoff and soil loss during 364 rainfall events, a simplified and convenient mathematical formula suitable for calculating the rainfall erosivity factor (R for the local region was established. Other factors of the universal soil loss equation (USLE model were also determined. Relative error analysis of the soil loss of various plots calculated by the USLE model on the basis of the observed values showed that the relative error ranged from -3.5% to 9.9% and the confidence level was more than 90%. In addition, the relative error was 5.64% for the terraced field and 12.36% for the sloping field in the practical application. Thus, the confidence level was above 87.64%. These results provide a scientific basis for forecasting and monitoring soil and water loss, for comprehensive management of small watersheds, and for soil and water conservation planning in the region.

  4. The Paleozoic-Mesozoic recycling of the Rakaia Terrane, South Island, New Zealand : sandstone clast and sandstone petrology, geochemistry, and geochronology

    International Nuclear Information System (INIS)

    Wandres, A.M.; Bradshaw, J.D.; Ireland, T.

    2005-01-01

    The Torlesse terranes - part of the New Zealand Eastern Province - are accretionary complexes that comprise an enormous volume of quartzofeldspathic sandstones and mudstones with subsidiary conglomerates plus minor oceanic assemblages. Two terranes are recognised in the South Island - the Permian to Late Triassic Rakaia Terrane and the Late Jurassic to Early Cretaceous Pahau Terrane. Sandstone clasts from two Rakaia Terrane and two Pahau Terrane conglomerates were collected. We present the first combined detailed information on petrography and geochemistry of Torlesse conglomerate sandstone clasts and use our own and published U-Pb SHRIMP detrital zircon age data to demonstrate the recycling of the Rakaia Terrane into Rakaia strata itself and into Pahau Terrane strata. Sandstone clast major and trace element chemical data largely support petrographic observations derived from thin-section analysis. The similarities of petrographic and geochemical data between sandstone clasts from the Rakaia Terrane and Rakaia sandstones suggest that clasts in the Permian Te Moana and Late Triassic Lake Hill Conglomerates were derived by autocannibalistic reworking of older, consolidated, Rakaia sediments. Data from sandstone clasts from the Pahau Terrane suggest that uplift of the Rakaia Terrane continued into the Cretaceous. These Pahau Terrane clasts indicate that at the time of the Pahau sedimentation Permian to early Late Triassic Rakaia rocks were exposed and recycled into the Pahau Basin. (author). 57 refs., 8 figs., 3 tables

  5. Transfer of Metasupracrustal Rocks to Midcrustal Depths in the North Cascades Continental Magmatic Arc, Skagit Gneiss Complex, Washington

    Science.gov (United States)

    Sauer, K. B.; Gordon, S. M.; Miller, R. B.; Vervoort, J. D.; Fisher, C. M.

    2017-12-01

    The metasupracrustal units within the north central Chelan block of the North Cascades Range, Washington, are investigated to determine mechanisms and timescales of supracrustal rock incorporation into the deep crust of continental magmatic arcs. Zircon U-Pb and Hf-isotope analyses were used to characterize the protoliths of metasedimentary and metaigneous rocks from the Skagit Gneiss Complex, metasupracrustal rocks from the Cascade River Schist, and metavolcanic rocks from the Napeequa Schist. Skagit Gneiss Complex metasedimentary rocks have (1) a wide range of zircon U-Pb dates from Proterozoic to latest Cretaceous and (2) a more limited range of dates, from Late Triassic to latest Cretaceous, and a lack of Proterozoic dates. Two samples from the Cascade River Schist are characterized by Late Cretaceous protoliths. Amphibolites from the Napeequa Schist have Late Triassic protoliths. Similarities between the Skagit Gneiss metasediments and accretionary wedge and forearc sediments in northwestern Washington and Southern California indicate that the protolith for these units was likely deposited in a forearc basin and/or accretionary wedge in the Early to Late Cretaceous (circa 134-79 Ma). Sediment was likely underthrust into the active arc by circa 74-65 Ma, as soon as 7 Ma after deposition, and intruded by voluminous magmas. The incorporation of metasupracrustal units aligns with the timing of major arc magmatism in the North Cascades (circa 79-60 Ma) and may indicate a link between the burial of sediments and pluton emplacement.

  6. Effect of Hydrograph Separation on Suspended Sediment Concentration Predictions in a Forested Headwater with Thick Soil and Weathered Gneiss Layers

    Directory of Open Access Journals (Sweden)

    Naoki Kabeya

    2014-06-01

    Full Text Available Two-component hydrograph separation using oxygen-18 concentrations was conducted at a sediment runoff observation weir installed in a small subcatchment of a forested gneiss catchment in Japan. The mean soil thickness of this catchment is 7.27 m, which comprises 3.29 m of brown forest soil (A and B layers and a 3.98-m layer of heavily weathered gneiss. Data were collected for a storm on 20–21 May 2003, and the percentage of event water separated by the stable isotope ratio in comparison with the total rainfall amount was about 1%. This value is within the ratio of a riparian zone in a drainage area. Temporal variation of suspended sediment concentration exhibited higher correlation with the event water component than with the total runoff or pre-event water component. This shows that the riparian zone causes rainwater to flow out quickly during a rain event, and that this is an important area of sediment production and transportation in a forested headwater with thick soil and weathered gneiss layers.

  7. Basic hypabissal, gondwanic magmatism: a new contribution for tecto no-stratigraphic terranes recognition in Uruguay

    International Nuclear Information System (INIS)

    Bossi, J.

    2006-01-01

    The possibility of having sufficient structural, geochronologic and geochemical data about the dykes and sills of Cuaro formation and the Corral de Piedra dyke swarm allowed to suggest the nature of the Mantle source and the injection process of each filonian set. Three units injected in the Gondwana continent were recognized: not outcropping Cuaro formation, at Piedra Alta Terrane; outcropping Cuaro Fm. in the Nico Perez Terrane, and the Corral de Piedra dyke swarm in the Cuchilla Dionisio terrane It was found different behavior in several important parameters in each one of them: mantelic source , melting percentage and crustal contamination. It may be concluded that Mantle nature and crust thickness and composition are different in each block, what supports. the idea that continental socle was constructed by amalgamation of different units of allocton provenence. When heat loss became difficult by the mega-continent consolidation, each fragment acted of different way. This represents a very strong argument favoring terrane Cuchilla Dionisio alloctony leaned to 525 Ma as regional geological mapping indicated

  8. Late Ordovician palaeogeography and the positions of the Kazakh terranes through analysis of their brachiopod faunas

    Science.gov (United States)

    Popov, Leonid E.; Cocks, Robin M.

    2017-09-01

    Detailed biogeographical and biofacies analyses of the Late Ordovician brachiopod faunas with 160 genera, grouped into 94 faunas from individual lithotectonic units within the Kazakh Orogen strongly support an archipelago model for that time in that area. The Kazakh island arcs and microcontinents within several separate clusters were located in the tropics on both sides of the Equator. Key units, from which the Late Ordovician faunas are now well known, include the Boshchekul, Chingiz-Tarbagatai, and Chu-Ili terranes. The development of brachiopod biogeography within the nearly ten million year time span of the Late Ordovician from about 458 to 443 Ma (Sandbian, Katian, and Hirnantian), is supported by much new data, including our revised identifications from the Kazakh Orogen and elsewhere. The Kazakh archipelago was west of the Australasian segment of the Gondwana Supercontinent, and relatively near the Tarim, South China and North China continents, apart from the Atashu-Zhamshi Microcontinent, which probably occupied a relatively isolated position on the south-western margin of the archipelago. Distinct faunal signatures indicate that the Kazakh terranes were far away from Baltica and Siberia throughout the Ordovician. Although some earlier terranes had joined each other before the Middle Ordovician, the amalgamation of Kazakh terranes into the single continent of Kazakhstania by the end of the Ordovician is very unlikely. The Late Ordovician brachiopods from the other continents are also compared with the Kazakh faunas and global provincialisation statistically determined.

  9. Lithospheric electrical structure of the middle Lhasa terrane in the south Tibetan plateau

    Science.gov (United States)

    Liang, Hongda; Jin, Sheng; Wei, Wenbo; Gao, Rui; Ye, Gaofeng; Zhang, Letian; Yin, Yaotian; Lu, Zhanwu

    2018-04-01

    The Lhasa terrane in southern Tibetan plateau is a huge tectono-magmatic belt and an important metallogenic belt. Its formation evolution process and mineralization are affected by the subduction of oceanic plate and subsequent continental collision. However, the evolution of Lhasa terrane has been a subject of much debate for a long time. The Lithospheric structure records the deep processes of the subduction of oceanic plate and continental collision. The magnetotelluric (MT) method can probe the sub-surface electrical conductivity, newly dense broadband and long period magnetotelluric data were collected along a south-north trending profile that across the Lhasa terrane at 88°-89°E. Dimensionality analyses demonstrated that the MT data can be interpreted using two-dimensional approaches, and the regional strike direction was determined as N110°E.Based on data analysis results, a two-dimensional (2-D) resistivity model of crust and upper mantle was derived from inversion of the transverse electric mode, transverse magnetic mode and vertical magnetic field data. Inversion model shows a large north-dipping resistor that extended from the upper crust to upper mantle beneath the Himalaya and the south of Lhasa Terrane, which may represent the subducting Indian continental lithosphere. The 31°N may be an important boundary in the Lhasa Terrane, the south performs a prominent high-conductivity anomaly from the lower crust to upper mantle which indicates the existence of asthenosphere upwelling, while the north performs a higher resistivity and may have a reworking ancient basement. The formation of the ore deposits in the study area may be related to the upwelling of the mantle material triggered by slab tearing and/or breaking off of the Indian lithosphere, and the mantle material input also contributed the total thickness of the present-day Tibetan crust. The results provide helpful constrains to understand the mechanism of the continent-continent collision and

  10. Origin and tectonic evolution of early Paleozoic arc terranes abutting the northern margin of North China Craton

    Science.gov (United States)

    Zhou, Hao; Pei, Fu-Ping; Zhang, Ying; Zhou, Zhong-Biao; Xu, Wen-Liang; Wang, Zhi-Wei; Cao, Hua-Hua; Yang, Chuan

    2017-12-01

    The origin and tectonic evolution of the early Paleozoic arc terranes abutting the northern margin of the North China Craton (NCC) are widely debated. This paper presents detrital zircon U-Pb and Hf isotopic data of early Paleozoic strata in the Zhangjiatun arc terrane of central Jilin Province, northeast (NE) China, and compares them with the Bainaimiao and Jiangyu arc terranes abutting the northern margin of the NCC. Detrital zircons from early Paleozoic strata in three arc terranes exhibit comparable age groupings of 539-430, 1250-577, and 2800-1600 Ma. The Paleoproterozoic to Neoarchean ages and Hf isotopic composition of the detrital zircons imply the existence of the Precambrian fragments beneath the arc terranes. Given the evidences from geology, igneous rocks, and detrital zircons, we proposed that the early Paleozoic arc terranes abutting the northern margin of the NCC are a united arc terrane including the exotic Precambrian fragments, and these fragments shared a common evolutionary history from Neoproterozoic to early-middle Paleozoic.

  11. Crustal structure of norther Oaxaca terrane; The Oaxaca and caltepec faults, and the Tehuacan Valley. A gravity study.

    Science.gov (United States)

    Campos-Enriquez, J. O.; Alatorre-Zamora, M. A.; Ramón, V. M.; Belmonte, S.

    2014-12-01

    Northern Oaxaca terrane, southern Mexico, is bound by the Caltepec and Oaxaca faults to the west and east, respectively. These faults juxtapose the Oaxaca terrane against the Mixteca and Juarez terranes, respectively. The Oaxaca Fault also forms the eastern boundary of the Cenozoic Tehuacan depression. Several gravity profiles across these faults and the Oaxaca terrane (including the Tehuacan Valley) enables us to establish the upper crustal structure of this region. Accordingly, the Oaxaca terrane is downward displaced to the east in two steps. First the Santa Lucia Fault puts into contact the granulitic basamental rocks with Phanerozoic volcanic and sedimentary rocks. Finally, the Gavilan Fault puts into contact the Oaxaca terrane basement (Oaxaca Complex) into contact with the volcano-sedimentary infill of the valley. This gravity study reveals that the Oaxaca Fault system gives rise to a series of east tilted basamental blocks (Oaxaca Complex?). A structural high at the western Tehuacan depression accomadates the east dipping faults (Santa Lucia and Gavilan faults) and the west dipping faults of the Oaxaca Fault System. To the west of this high structural we have the depper depocenters. The Oaxaca Complex, the Caltepec and Santa Lucia faults continue northwestwards beneath Phanerozoic rocks. The faults are regional tectonic structures. They seem to continue northwards below the Trans-Mexican Volcanic Belt. A major E-W to NE-SW discontinuity on the Oaxaca terrane is inferred to exist between profiles 1 and 2. The Tehuacan Valley posses a large groundwater potential.

  12. Gneisses of Brazil's cultural heritage buildings and its most frequent degradations

    Science.gov (United States)

    Gilberto Costa, Antônio

    2017-04-01

    Macroscopic descriptions of cultural heritage buildings constructed using gneisses in the cities of Rio de Janeiro, Belo Horizonte and Ouro Preto, Brazil, allowed to identify alterations and degradations, in part conditioned by the mineralogical composition and the structures present in these stone materials. It is important to emphasize that: - some changes still begin in the environments where these materials were formed, experiencing an intensification from the processes of extraction, processing and application; - modifications occurring after the applications are understood herein as degradations. The studied gneisses present banding consisting of parts with different thicknesses and mineralogical contents. Due to these differentiated contents, clear bands were identified and constituted essentially by felsic minerals, such as feldspars and quartz, as well as dark bands formed by mafic minerals represented by: biotite, garnets, amphiboles, such as hornblende or pyroxene (hyperstene). In addition to these minerals, low contents of oxides and sulphides were found. Also under the influence of this distribution of minerals, planar structures or foliations, more or less developed, that can be very penetrative have been identified, mainly when these rocks were submitted to the performance of milonitization processes. From the set of changes and degradations observed stand out those related to the decomposition of minerals that make up these materials. In these cases, feldspars and other silicates, such as micas, amphiboles and pyroxenes, were decomposed due to the hydrolysis and products were generated which compromised the resistance of these stone materials, leading to their consequent disintegration. On the other hand, the presence of expansive clays in these products, caused volume increases which also contributed to the expansion of the weathered surface layer (blistering). This process may result detachments in the form of scales to cavities in cases of

  13. Modeling the effects of structure on seismic anisotropy in the Chester gneiss dome, southeast Vermont

    Science.gov (United States)

    Saif, S.; Brownlee, S. J.

    2017-12-01

    Compositional and structural heterogeneity in the continental crust are factors that contribute to the complex expression of crustal seismic anisotropy. Understanding deformation and flow in the crust using seismic anisotropy has thus proven difficult. Seismic anisotropy is affected by rock microstructure and mineralogy, and a number of studies have begun to characterize the full elastic tensors of crustal rocks in an attempt to increase our understanding of these intrinsic factors. However, there is still a large gap in length-scale between laboratory characterization on the scale of centimeters and seismic wavelengths on the order of kilometers. To address this length-scale gap we are developing a 3D crustal model that will help us determine the effects of rotating laboratory-scale elastic tensors into field-scale structures. The Chester gneiss dome in southeast Vermont is our primary focus. The model combines over 2000 structural data points from field measurements and published USGS structural data with elastic tensors of Chester dome rocks derived from electron backscatter diffraction data. We created a uniformly spaced grid by averaging structural measurements together in equally spaced grid boxes. The surface measurements are then projected into the third dimension using existing subsurface interpretations. A measured elastic tensor for the specific rock type is rotated according to its unique structural input at each point in the model. The goal is to use this model to generate artificial seismograms using existing numerical wave propagation codes. Once completed, the model input can be varied to examine the effects of different subsurface structure interpretations, as well as heterogeneity in rock composition and elastic tensors. Our goal is to be able to make predictions for how specific structures will appear in seismic data, and how that appearance changes with variations in rock composition.

  14. Skew-adjacency matrices of graphs

    NARCIS (Netherlands)

    Cavers, M.; Cioaba, S.M.; Fallat, S.; Gregory, D.A.; Haemers, W.H.; Kirkland, S.J.; McDonald, J.J.; Tsatsomeros, M.

    2012-01-01

    The spectra of the skew-adjacency matrices of a graph are considered as a possible way to distinguish adjacency cospectral graphs. This leads to the following topics: graphs whose skew-adjacency matrices are all cospectral; relations between the matchings polynomial of a graph and the characteristic

  15. Geochemistry of Gneisses from Dabie Complex and Tongbai Complex in Qinling-Tongbai-Dabie Orogenic Belt: Implications for Location of Yangtze-Sino-Korean Suture

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The Dabie complex (DC) and the Tongbai complex (TBC) are separately distributed in the middle and eastern parts of the Qinling-Tongbai-Dabie orogenic belt. In this study, the Dabie complex can be divided into two units: one is the complex with no high pressure and ultrahigh pressure metamorphic rocks (DC1), and the other is the complex containing coesite-bearing eclogite lenses or boudins (DC2). Gneisses are predominant in the TBC, DC1 and DC2. Major and trace element data of gneisses in the TBC, DC1 and DC2 show them to be the orthogneisses. The gneisses in the DC1 have higher incompatible element contents and higher ratios of w(K2O)/w(Na2O) and w(La)n/w(Yb)n than those in the DC2. However, no obvious differences arise in other element contents and the ratios of w(La)/w( Nb), w(Nb)/w(Th), w(Nb)/w(Hf), w(Ba)/w(La), w(Sm)/w(Nd) and w(Th)/w(U) between the gneisses in the DC2 and those in the DC1. These observations suggest that the protoliths of the gneisses in the DC2 have affinities to those in the DC1. The difference between the DC1 and DC2 gneisses in incompat- ible element contents could reflect the difference in their partial melting extent. The TBC gneisses are geochemically similar to the DC1 gneisses, suggesting that the TBC and DC1 gneisses are the same lithologic unit in the Qinling-Tongbai-Dabie orogenic belt and that they have experienced similar formations and evolution histories. In the Qinling-Tongbai area, the TBC is part of the northern blocks of the Yangtze craton. Given the similarity of geochemical characteristics, the rock assemblage and the ages between the TBC and DC1 gneisses, we can infer that the Dabie complex also belongs to the northern blocks of the Yangtze craton. In terms of the distribution of eciogites and metamorphic facies, we propose that the collisionai suture in the Dabie area is distributed along the Xiaotian-Mozitan fault, at the contact with the Shang-Dan-Tongbai fault to the west.

  16. Unusual central Nevada geologic terranes produced by Late Devonian Antler orogeny and Alamo impact

    Science.gov (United States)

    Poole, Forrest G.; Sandberg, Charles

    2015-01-01

    This Special Paper is the product of nearly 25 years of geologic investigations. It is an exposition of two small areas, both less than 25 km east of the Mississippian Roberts Mountains allochthon, but each displaying a different, unique geologic terrane, previously undocumented in Nevada and perhaps in North America. One area, the Bisoni-McKay, at the south end of the Fish Creek Range, displays an olistostrome, shed eastward during the late Late Devonian (early Famennian) from a migrating Antler orogenic forebulge. The other, the Warm Springs–Milk Spring, at the south end of the Hot Creek Range, displays a deeper marine terrane affected by the early Late Devonian (middle Frasnian) Alamo impact.

  17. Thermochronology of the Sulu ultrahigh-pressure metamorphic terrane: Implications for continental collision and lithospheric thinning

    Science.gov (United States)

    Liu, Li-Ping; Li, Zheng-Xiang; Danišík, Martin; Li, Sanzhong; Evans, Noreen; Jourdan, Fred; Tao, Ni

    2017-08-01

    The thermal history of the Dabie-Sulu orogenic belt provides important constraints on the collision process between the South China and North China blocks during the Mesozoic, and possible lithospheric thinning event(s) in the eastern North China Block. This study reports on the thermal evolution of the Sulu ultrahigh-pressure metamorphic (UHP) terrane using zircon U-Pb geochronology and multiple thermochronology methods such as mica and hornblende 40Ar/39Ar, zircon and apatite fission track, and zircon and apatite (U-Th)/He dating. 40Ar/39Ar and zircon (U-Th)/He data show that the UHP terrane experienced accelerated cooling during 180-160 Ma. This cooling event could be interpreted to have resulted from extensional unroofing of an earlier southward thrusting nappe, or, more likely, an episode of northward thrusting of the UHP rocks as a hanging wall. A subsequent episode of exhumation took place between ca. 125 Ma and 90 Ma as recorded by zircon (U-Th)/He data. This event was more pronounced in the northwest section of the UHP terrane, whereas in the southeast section, the zircon (U-Th)/He system retained Jurassic cooling ages of ca. 180-160 Ma. The mid-Cretaceous episode of exhumation is interpreted to have resulted from crustal extension due to the removal of thickened, enriched mantle. A younger episode of exhumation was recorded by apatite fission track and apatite (U-Th)/He ages at ca. 65-40 Ma. Both latter events were linked to episodic thinning of lithosphere along the Sulu UHP terrane in an extensional environment, likely caused by the roll-back of the Western Pacific subduction system.

  18. Primordial crustal growth in northern Nigeria: preliminary Rb-Sr and Sm-Nd constraints from Kaduna migmatite-gneiss complex

    International Nuclear Information System (INIS)

    Dada, S. S.; Briqueu, L.; Birck, J. L.

    1998-01-01

    The Kaduna Migmatite-Gneiss Complex in the central area of the Northern shield includes variably migmatised granitotrondhjemitic gneisses and amphibolite of hitherto unknown age. The amphibolite enclaves and dykes are metatholeiites with comparatively unfractionated rare-earth patterns. The two main rock units (TTG and amphibolite) exhibit complementary geochemical signatures in the normalised abundance patterns of relatively incompatible elements and suggest possible derivation of the gneisses from subduction related mafic material. Sm-Nd and Rb-Sr isotopic data document early Archaean crustal formation of new crust and its subsequent late Archaean differentiation. These preliminary results form an evidence for a more extended crustal history in the heart of the Pan-African domain (ca. 600 Ma.). They suggest the differentiation of juvenile crustal protolith from a chondritic reservoir about 3.5 Ga. for the gneiss-amphibolite bimodal suite. A tectonothermal event about 3.1-3.0 Ga led to the emplacement of an early gneiss as indicated from Rb-Sr and U-Ph zircon analyses. Subsequent differentiation and/or reworking around 2.8-2.7 Ga is coherent with the Liberian orogeny within the West African- Latino American subregion

  19. A geochemical and Pb, Sr isotopic study of the evolution of granite-gneisses from the Bastar craton, Central India

    International Nuclear Information System (INIS)

    Sarkar, G.; Paul, D.K.; Misra, V.P.; de Laeter, J.R.; Mc Naughton, N.J.

    1990-01-01

    Preliminary Pb-Pb and Rb-Sr geochronology of granitic and gneissic rocks from the Sukma area of the Bastar craton, Central India, provides important constraints on crustal evolution. Much of the craton is made up of felsic orthogneisses and younger granitic intrusives, compositionally ranging from tonalite to granite. Pb-Pb isotopic data suggest the presence of ca. 3.0 Ga old gneisses. Younger granitic intrusives have been dated at ca. 2.6 Ga which represents a widespread resetting and/or emplacement event. Comparison of the Pb-Pb and Rb-Sr whole rock ages suggests that the latter were more perturbed after the gneiss-forming or emplacement events. All rock suites show significant geological scatter of isotopic data probably because of sampling on a regional scale, and reflect multi-stage isotopic evolution in a complex terrain. The present isotopic data indicate the presence of Archaean rock in the Bastar craton and suggest temporal similarity with the oldest crustal rocks in the Singhbhum and Dharwar cratons. (author). 18 refs., 4 tabs., 8 figs

  20. Isotopic provenance analysis and terrane tectonics: a warning about sediment transport distances

    International Nuclear Information System (INIS)

    Bassett, K.N.

    1999-01-01

    Full text: In the last 10 years the field of provenance analysis has undergone a revolution with the development of single-crystal isotopic dating techniques, the most common being U/Pb zircon and 40Ar/39Ar techniques. These have allowed age determination of single crystals thus providing more detail about probable provenance of each individual grain rather than an averaged population of grains. The usefulness for resolving complex terrane accretion and translation histories was immediately obvious and there have been many studies in many different regions aimed at tracking terrane motions by provenance of individual grains upward through the stratigraphy of a basin. Recent research in the North American Cordilleran terranes and in the New Zealand Torlesse Superterrane show how widely used and powerful these provenance analysis techniques are. However, isotopic provenance analysis has often been presented as key information to resolve controversies around terrane translation histories with very little discussion of the context of sedimentary facies and sediment transport mechanisms. An example is the recent use of U/Pb detrital zircon ages as the supposedly controversy-ending evidence for the amount of lateral translation of the Insular Superterrane in British Columbia (Baja BC) (Mahoney et al., 1999). The zircon grains were separated from fine-grained turbidite deposits and could easily have been transported over very large distances by a variety of mechanisms; yet they were presented as definitively resolving the Baja BC controversy. Modern examples illustrate the problem of using the provenance of fine grained sediment to constrain terrane tectonics. Sediment in the tip of the Bengal submarine fan was transported ∼3000 km from source, first by fluvial processes then by sediment gravity flow in the submarine fan. The detrital isotopic ages of single grains are the same as the depositional ages indicating a very rapid unroofing and transport rate with minimal

  1. Evidence From Detrital Zircon U-Pb Analysis for Suturing of Pre-Mississippian Terranes in Arctic Alaska

    Science.gov (United States)

    Moore, T. E.; Potter, C. J.; O'Sullivan, P. B.; Aleinikoff, J. N.

    2007-12-01

    900 Ma and 1200-1450 Ma that are not seen in the Neroukpuk sample, as well as a cluster of ages at 320-390 Ma. This sample indicates that the Neroukpuk is not the only source of zircons for Mississippian strata in the northeast Brooks Range. The samples from the northeastern Brooks Range contain zircon distributions similar to those reported from autochthonous North American strata in east-central Alaska and are strikingly different from those in western and southern parts of the Arctic Alaska terrane. Peaks at ~1.8 Ga are subdued or missing in the latter samples and 1.5-1.6 Ga grains, a magmatic gap in Laurentia, are present in the Lisburne Peninsula and North Slope samples. In view of these data, field and seismic evidence for significant Devonian deformation in northern Alaska, and likely plate configurations for that time, northern Alaska probably records early to mid-Paleozoic closing of the Iapatus Ocean and collisional suturing of non-Laurentian continental blocks with northwestern North America. This suggests that Devonian deformation in Arctic Alaska represents an important, northern element of the Caledonian deformational system that probably once linked up with Caledonian structures in the Canadian Arctic Islands and adjacent continental margin region.

  2. The Svalbard Caledonides - a collage of Laurentian, Timanian and exotic terranes assembled by Silurian - Late (?) Devonian transcurrent faulting.

    Science.gov (United States)

    Andresen, Arild; Gasser, Deta

    2014-05-01

    New field and geochronological data from NE Greenland and Svalbard indicate that most of the sub-terranes making up the Svalbard Caledonides (Eastern, Northwestern and Southwestern Terranes) are derived from Laurentias eastern margin. The Neoproterozoic deposits of the Eastern Terrane (Nordaustlandet) show an almost one to one correlation with the Late Neoproterozoic Eleonore Bay Supergroup in NE Greenland. Great similarities also exist between the substratum to the Neoproterozoic deposits in the two areas. The "Barentsian plate/continent" is interpreted to be derived from Laurentias eastern margin Lithologic similarities also exist between parts of the Northwestern Terrane and NE Greenland. The geologic evolution of Svalbard`s Southwestern Terrane, with subduction complexes and Late Neoproterozoic intrusives (Timanian ?) is poorly understood. It will, however, be argued that there is no need to invoke considerable right lateral strike-slip movement of the Motalefjellet subduction complex and related rocks from a position in Arctic Canada to their present position within the Southwestern Terrane, as proposed by some authors. The structural grain of the Svalbard Caledonides, oblique to East Greenland and Scandinavian Caledonides, as well as the Ellesmerian Orogen, is interpreted to be due to counter-clockwise rotation (c. 45o) of the Caledonian trend. A counter-clockwise rotation is to be expected when the northward moving terranes reached the E-W trending Franklinian Basin north of Greenland/Laurentia, which in Early Devonian time had not yet started to close. The model predicts that there should be a dramatic change in the Caledonian structural grain somewhere south of Bjørnøya. It is furthermore speculated that the fan-shaped orientation of Late Paleozoic rift basins in the Western Barents Sea is controlled by reactivation of the rotated structural trend (e.g. Billefjorden Fault Zone and Billefjorden Trough).

  3. Constraints from geochemistry and oxygen isotopes for the hydrothermal origin of orthoamphibole mafic gneiss in the New Jersey Highlands, north-central Appalachians, USA

    Science.gov (United States)

    Volkert, Richard A.; Peck, William H.

    2017-12-01

    Rare exposures of orthoamphibole mafic (Oam) gneiss of Mesoproterozoic age in the north-central Appalachians are confined to the northwestern New Jersey Highlands where they form thin lens-shaped bodies composed of gedrite and sparse anthophyllite, oligoclase (An13-An20), biotite, magnetite, and local fluorapatite, rutile, and ilmenite. The gneiss is penetratively foliated and has sharp, conformable contacts against enclosing supracrustal paragneiss and marble. Orthoamphibole mafic gneiss is characterized by low SiO2 (48 ± 2.5 wt%), CaO (1.9 ± 1.3 wt%), and high Al2O3 (18 ± 1.2 wt%), Fe2O3 (10.5 ± 1.6 wt%), and MgO (12 ± 2.3 wt%). Trace element abundances overlap those of unaltered amphibolites in the study area and, coupled with δ18O values of 9.45 ± 0.6‰ (VSMOW) from gedrite separates, support an origin from a basalt protolith. The geochemical and isotopic data are consistent with the formation of Oam gneiss through sea floor hydrothermal alteration of basalt at low temperature of 150-200 °C. Mass-balance calculations indicate gains during alteration mainly in MgO and Al2O3 and losses in CaO, Sr, and light rare earth elements. Our results are compatible with the pre-metamorphic alteration of the basalt protoliths through chloritization and plagioclase dissolution that produced a Mg-rich and Ca-poor rock. Subsequent metamorphism of this chlorite-rich rock to the current mineral assemblage of Oam gneiss took place at ca. 1045 Ma, during the Ottawan phase of the Grenvillian Orogeny. The close spatial association in the study area of Oam gneiss bodies and sulfide occurrences suggests an affinity to the style of mineralization associated with volcanogenic massive sulfide (VMS)-type deposits.

  4. Distribution and Diversity of Carboniferous and Permian Colonial Rugose Coral Faunas in Western North America: Clues for Placement of Allochthonous Terranes

    Directory of Open Access Journals (Sweden)

    Calvin H. Stevens

    2012-05-01

    Full Text Available Colonial rugose corals are common in western cratonal North America and in some of the allochthonous terranes, now amalgamated against its western margin. Throughout the Late Paleozoic, the coral faunas in these two different settings were significantly different. Comparisons of these faunas suggest that during the Mississippian the Alexander terrane probably was southwest of Arctic Alaska and the Stikine terrane probably lay west of the southern part of the North American craton. The Cache Creek terrane lay far out in the Paleopacific Ocean. The Pennsylvanian faunas suggest that the Quesnellia and Eastern Klamath terranes were situated southwest of Arctic Alaska and the Alexander terrane was somewhat farther southwest and farther from cratonal North America. The Stikine terrane continued to be positioned west of the southern part of the North American craton. During the Early Permian, terranes with a cratonal faunal aspect may have lain 2000–3000 km west of cratonal North America and latitudinally generally southwest of their present positions. In the Middle Permian these terranes were carried southward relative to the North American craton. Simultaneously the Tethyan Realm expanded eastward.

  5. Two possibilities for New Siberian Islands terrane tectonic history during the Early Paleozoic based on paleomagnetic data

    Science.gov (United States)

    Metelkin, Dmitry V.; Chernova, Anna I.; Vernikovsky, Valery A.; Matushkin, Nikolay Yu.

    2017-04-01

    The New Siberian Islands (NSI), located in the East Siberian Sea in the junction region of various structural elements, are a key target for deciphering the tectonic evolution of the Eastern Arctic. In recent years, we went on several expeditions and gathered an extensive geological material for this territory. Among other things, we could prove that the basement of the De Long and Anjou archipelagos structures is Precambrian and the overlying Paleozoic sections formed within the same terrane. The form of the boundaries of the NSI terrane are actively debated and are probably continued from the Lyakhovsky islands in the south-west to the southern parts of the submerged Mendeleev Ridge, for which there is increasing evidence of continental crust. Today there are several models that interpret the Paleozoic-Mesozoic tectonic history and structural affiliation of the NSI terrane. Some propose that the Paleozoic sedimentary section formed in a passive margin setting of the Siberian paleocontinent. Others compare its history with marginal basins of the Baltica and Laurentia continents or consider the NSI terrane as an element of the Chukotka-Alaska microplate. These models are mainly based on results of paleobiogeographical and lithological-facies analyses, including explanations of probable sources for detrital zircons. Our paleomagnetic research on sedimentary, volcanogenic-sedimentary and igneous rocks of the Anjou (Kotelny and Bel'kovsky islands) and De Long (Bennett, Jeannette and Henrietta islands) archipelagos let us calculate an apparent polar wander path for the early Paleozoic interval of geological history, which allows us to conclude that the NSI terrane could not have been a part of the continental plates listed above, but rather had active tectonic boundaries with them. Our paleomagnetic data indicate that the NSI terrane drifted slowly and steadily in the tropical and subtropical regions no higher than 40 degrees. However, the main uncertainty for the

  6. Low palaeoelevation of the northern Lhasa terrane during late Eocene: Fossil foraminifera and stable isotope evidence from the Gerze Basin.

    Science.gov (United States)

    Wei, Yi; Zhang, Kexin; Garzione, Carmala N; Xu, Yadong; Song, Bowen; Ji, Junliang

    2016-06-08

    The Lhasa terrane is a key region for understanding the paleoelevation of the southern Tibetan Plateau after India-Asia collision. The Gerze Basin, located in the northern part of the Lhasa terrane, is a shortening-related basin. We discovered Lagena laevis (Bandy) fossils in upper Eocene strata of the Gerze Basin. This type of foraminifera is associated with lagoon and estuarine environments, indicating that the northern part of the Lhasa terrane was near sea level during the late Eocene. We speculate that these foraminifera were transported inland by storm surges to low elevation freshwater lakes during times of marine transgressions. This inference is consistent with the relatively positive δ(18)O values in carbonate from the same deposits that indicate low palaeoelevations close to sea level. Considering the palaeoelevation results from the nearby Oligocene basins at a similar latitude and the volcanic history of the Lhasa terrane, we infer that large-magnitude surface uplift of the northern Lhasa terrane occurred between late Eocene and late Oligocene time.

  7. The Apuseni Mountains, Romania, a Variscan Collage of Ordovician Gondwanan Terranes

    Science.gov (United States)

    Balintoni, I. C.; Balica, C.; Zaharia, L.; Chen, F.; Cliveti, M.; Hann, H. P.; Ghergari, L.

    2007-12-01

    The basement of the Apuseni Mountains, Romania, consists of three pre-Variscan terranes, sutured during an Early Variscan amalgamation around 351 Ma (Balintoni et al., this volume). The northern Someş Terrane (ST) is predominantly gneissic, while the southern Baia de Arieş Terrane (BAT) is dominated by the presence of large carbonate lenses, although metagranites and other types of orthogneisses can be found. These two terranes are sutured through the Biharia terrane, probably an accreted island arc. LA-ICP-MS datings on zircons extracted from orthogneisses and metagranites were performed in order to constrain the age of ST and BAT. A number of previously CL-imaged crystals were ablated at the China's University of Geosciences, Wuhan. From ST we dated an orthogneiss occurring in structurally lowermost position, a metatuff situated in the upper strongly retrogressed part and a twenty detrital crystal population sampled from a metasandstone. The 206Pb/238U apparent ages were projected using the weighted average plots.A magmatic crystallization age of 472.8±5.0 Ma (Upper Early Ordovician) resulted for one of the orthogneiss samples, besides several older ages at 505.7, 566.3 and 708.2 Ma corresponding to inherited cores. Another sample from the same rock appeared strongly affected by lead loss during a later thermotectonic event, most of the apparent ages grouping around 352±14 Ma. This age is similar with the age of the suture between ST and BT (Balintoni et al., this volume). The main zircon population of one metatuff sample furnished an averaged age of 423±7.2 Ma, also found in two additional samples, but their significance is obscure for the moment. Two primary magmatic ages arise at 464.2 and 473.8 Ma, an older value of 758.7 Ma corresponding to an inherited core. Detrital zircon ages range between 534.8 and 2596.8 Ma. The younger value represents an upper age constraint for the protolith age of ST-rocks. From BAT we dated the Lupşa metaporphyroid and the

  8. Seismic signatures of the Pan-African orogeny: implications for southern Indian high-grade terranes

    Science.gov (United States)

    Rai, Abhishek; Gaur, V. K.; Rai, S. S.; Priestley, K.

    2009-02-01

    We present the results of a study designed to investigate and compare the seismic characteristics of the once contiguous terranes of eastern Gondwanaland, now incorporated in five separated continental masses, which, during the Neoproterozoic (~600Ma) Pan-African orogeny, suffered a high degree of thermal stress and deformation. Receiver functions and surface wave data from stations located in East Antarctica, Sri Lanka, the southern-Indian high-grade terranes, Madagascar and the Tanzania-Mozambique belt, were used to determine the shear-wave velocity structure, Moho depth and VP/VS values of the respective crustal segments. This study provides an additional dimension to the otherwise well-documented characteristic petrology of their surface exposures and other geological signatures such as their extensive granulitization and gem formation during the Pan-African event. Analysis of the receiver functions and surface wave data for these seismic stations located on their present day widely distributed continental fragments have been made. It is observed that with the exception of KOD (at Kodaikanal hill), situated on the southern Indian granulites having the thickest crust (~43.5 km), most of the Pan-African granulitic terranes have a crustal thicknesses of ~37 +/- 0.8km, with a transition to higher velocity at mid-crustal depths, and that their bulk composition is felsic. Average crustal VP/VS values (1.704 +/- 0.03) and thicknesses (37.8 +/- 0.8km), for four stations (SYO, PALK, TRV and ABPO), now located in East Antarctica, Sri Lanka, India and Madagascar, respectively, show remarkable similarity, indicating that the Pan-African orogeny was extensive enough to reorder the crustal structure of a wide region with a broadly similar stamp.

  9. Paleomagnetic Constraints on the Tectonic History of the Mesozoic Ophiolite and Arc Terranes of Western Mexico

    Science.gov (United States)

    Boschman, L.; Van Hinsbergen, D. J. J.; Langereis, C. G.; Molina-Garza, R. S.; Kimbrough, D. L.

    2017-12-01

    The North American Cordillera has been shaped by a long history of accretion of arcs and other buoyant crustal fragments to the western margin of the North American Plate since the Early Mesozoic. Accretion of these terranes resulted from a complex tectonic history interpreted to include episodes of both intra-oceanic subduction within the Panthalassa/Pacific Ocean, as well as continental margin subduction along the western margin of North America. Western Mexico, at the southern end of the Cordillera, contains a Late Cretaceous-present day long-lived continental margin arc, as well as Mesozoic arc and SSZ ophiolite assemblages of which the origin is under debate. Interpretations of the origin of these subduction-related rock assemblages vary from far-travelled exotic intra-oceanic island arc character to autochthonous or parautochthonous extended continental margin origin. We present new paleomagnetic data from four localities: (1) the Norian SSZ Vizcaíno peninsula Ophiolite; (2) its Lower Jurassic sedimentary cover; and (3) Barremian and (4) Aptian sediments derived from the Guerrero arc. The data show that the Mexican ophiolite and arc terranes have a paleolatitudinal plate motion history that is equal to that of the North American continent. This suggests that these rock assemblages were part of the overriding plate and were perhaps only separated from the North American continent by temporal fore- or back-arc spreading. These spreading phases resulted in the temporal existence of tectonic plates between the North American and Farallon Plates, and upon closure of the basins, in the growth of the North American continent without addition of any far-travelled exotic terranes.

  10. Piedra lata terrane of Uruguay: Rb-Sr geochronological data of two new paleoproterozoic (transamazonian) granitoids

    International Nuclear Information System (INIS)

    Cingolani, C; Bossi, J; Varela, R; Maldonado, S.; Pineyro, D.; Schipilov, A

    2001-01-01

    The Precambrian basement of Uruguay consists of three major terranes separated and crosscut by wide NE-striking subvertical transcurrent shear zones. The western terrane as a part of the Rio de la Plata Craton is known as the Piedra Alta Terrane (PAT). This is separated from the Nico Perez Terrane by the Sarandi del Yi-Piri olis subvertical shear zone (Bossi et al., 1993). A mafic dykes complex intruded the PAT at 1.8 Ga and was not later deformed. The PAT has equivalent rocks in the igneous-metamorphic basement of Tandilia region and the Martin Garcia Island, Buenos Aires Province, Argentina (Dalla Salda et al., 1988; Cingolani and Dalla Salda, 2000). The PAT shows no evidence of the Neoproterozoic orogenies and is considered a best preserved Paleoproterozoic block (Transamazonian Cycle). It contains three E-W trending belts of volcano-sedimentary rocks with low grade metamorphism. These are from south to north: Pando, San Jose and Andresito belts (Bossi et al., 1996). Associated with them, three granitic-gneissic zones he Ecilda Paullier, Florida and Feliciano- were recognized with magmatic intrusives emplaced at different crustal levels. The San Jose belt is the largest supracrustal unit and contains abundant volcanic and volcaniclastic rocks of low grade metamorphic (Paso Severino Fm.) with sheets of granitic rocks intercalated (Mutti et al., 1996; Bossi et al., 1996). The associated granitic rocks are of large areal extension, mostly granodiorites and tonalites, and minor monzogranite and gabbro (e.g. Cerro Rospide region), including xenoliths from Paso Severino Fm. Towards the north of the San Jose belt an important Florida granitized zone is developed in the central part of the PAT, where the Pintos massif was recognized. The main purpose of this contribution is to offer new Rb-Sr geochronological data from two granitoid units, The Cerro Rospide intrusive in Paso Severino Fm. and Pintos massif included in medium grade migmatic-metamorphic complex and its

  11. Charnockitic ortho gneisses and mafic granulites of Cerro Olivo complex, proterozoic basement of SE Uruguay, Part 1: Geology

    International Nuclear Information System (INIS)

    Masquelin, H.

    2008-01-01

    Charnockitic ortho gneisses and mafic granulite s exposed in the Cerro Bori Block, in the center of Punta del Este terrain, were the first document occurrence of granulitic rocks from SE sector of the Uruguayan Shield. We present here their main geological features, with the purpose to suggest some petrologic and structural interesting problems for a future lithogeochemical, mineral chemistry, stable isotopes and fluid inclusion studies about these rocks. We propose some speculation form field-based studies considering a cognate magmatic origin of both kinds of rocks, previous to a homogeneous granulitic metamorphism. Some structural evidences indicate that after their uplift, these rocks were located on over thickened crust, at great to medium deepness. A cataclasis during anatexis and amphibolite-facies mineral association stabilization are common phenomena. Other evidences suggest a polycyclic character for the regional geologic evolution

  12. Interpretation of gravity profiles across the northern Oaxaca terrane, its boundaries and the Tehuacán Valley, southern Mexico

    Science.gov (United States)

    Campos-Enríquez, J. O.; Alatorre-Zamora, M. A.; Keppie, J. D.; Belmonte-Jiménez, S. I.; Ramón-Márquez, V. M.

    2014-12-01

    A gravity study was conducted across the northern Oaxaca terrane and its bounding faults: the Caltepec and Oaxaca Faults to the west and east, respectively. These faults juxtapose the Oaxaca terrane against the Mixteca and Juarez terranes, respectively. The Oaxaca Fault also forms the eastern boundary of the Cenozoic Tehuacán depression. On the west, at depth, the Tehuacán valley is limited by the normal buried Tehuacán Fault. This gravity study reveals that the Oaxaca Fault system gives rise to a series of east tilted basamental blocks (Oaxaca Complex). The tectonic depression is filled with Phanerozoic rocks and has a deeper depocenter to the west. The gravity data also indicate that on the west, the Oaxaca Complex, the Caltepec and Santa Lucia faults continue northwestwards beneath Phanerozoic rocks. A major E-W to NE-SW discontinuity is inferred to exist between profiles 1 and 2.

  13. Notes on epilithic and epigeic lichens from granite and gneiss outcrops in mountains of Makedonia, Greece, with emphasis on northern species

    DEFF Research Database (Denmark)

    Christensen, Steen

    2014-01-01

    The epilithic and epigeic lichen flora of eight localities with granite and gneiss outcrops in the mountains of Makedonia, N Greece has been investigated. Of the 46 taxa reported, seven species are new to Greece, viz.: Brodoa oroarcti­ca, Candelariella coralliza, Cetraria ericetorum, Lecanora...

  14. Elastic anisotropy of layered rocks: Ultrasonic measurements of plagioclase-biotite-muscovite (sillimanite) gneiss versus texture-based theoretical predictions (effective media modeling)

    Czech Academy of Sciences Publication Activity Database

    Ivankina, T. I.; Zel, I. Yu.; Lokajíček, Tomáš; Kern, H.; Lobanov, K. V.; Zharikov, A. V.

    712/713, 21 August (2017), s. 82-94 ISSN 0040-1951 R&D Projects: GA MŠk LH13102 Institutional support: RVO:67985831 Keywords : compositional layering * crystallographic texture * effective elastic properties calculation * neutron diffraction * plagioclase-biotite-muscovite (sillimanite) gneiss * velocity measurements Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 2.693, year: 2016

  15. Geodynamic evolution of the Pan-African lower crust in Sri Lanka : structural and petrological investigations into a high-grade gneiss terrain

    NARCIS (Netherlands)

    Kriegsman, L.

    1993-01-01

    Some main objectives of present-day geological research are to assess the role of the lower crust in collision and extensional tectonics and to unravel the mechanism and timing of crustal growth. Both objectives require input from the study of high-grade gneiss terrains, notably data concerning

  16. MULTIDISCIPLINARY APPROACH TO STUDY MIGMATITES: ORIGIN AND TECTONIC HISTORY OF THE NASON RIDGE MIGMATITIC GNEISS, WENATCHEE BLOCK, CASCADES CRYSTALLINE CORE, WA, USA

    Directory of Open Access Journals (Sweden)

    Stowell Harold H.

    2008-12-01

    Full Text Available The Nason Ridge Migmatitic Gneiss of the Cascades Core is a migmatitic unit comprising concordant pelitic schist and gneiss, amphibolite, and tonalite gneiss, and cross cutting tonalite, quartz-rich granitoid, and pegmatite. There are several generations of 'igneous' lithologies (leucosomes = tonalite, quartz-rich granitoid, and pegmatite some of which are concordant; others clearly crosscut the strongly deformed host rocks. The host rocks are interpreted to be Chiwaukum Schist with metasedimentary (pelitic schist and some gneiss and metavolcanic(amphibolites origins. Metamorphic fabric in the Nason Ridge Migmatitic Gneiss is characterized by preferred orientation of platy minerals (continuous schistosity, compositional layering, mineral lineations (elongate grains and grain aggregates, and non-coaxial deformational features (asymmetric augen, grain offsets,rotated porphyroblasts, etc.. Compositional layering is characterized by quartz-plagioclase lenses and patches (mm to cm scale and by large variations in biotite content. This composite fabric is faulted and folded by mesoscopic structures. The most strongly foliated leucosomes (gneissic tonalites are generally concordant with the regional trend of foliation, while weakly foliated leucosomes (tonalites and pegmatite veins crosscut host rock and tonalite gneisses. Thin melanosome layers (biotiteand amphibole schist are developed locally around quartz - plagioclase lenses and patches. Metamorphism in the Nason Ridge Migmatitic Gneiss and the nearby Chiwaukum Schist likely peaked after intrusion of the Mt. Stuart Batholith ca. 91-94 Ma. Peak temperatures and pressures for the Nason Ridge Migmatitic Gneiss in the Wenatchee Ridge and Pacific Crest areas were 650 - 720 °C and 6 - 9 kbar with a pressure increase of £ 2.0 kbar during metamorphism. Thermodynamic modeling indicates that hydrous partial melting would begin at ca. 660 °C and is relatively pressure independent. Field

  17. Shallow magnetic inclinations in the Cretaceous Valle Group, Baja California: remagnetization, compaction, or terrane translation?

    Science.gov (United States)

    Smith, Douglas P.; Busby, Cathy J.

    1993-10-01

    Paleomagnetic data from Albian to Turonian sedimentary rocks on Cedros Island, Mexico (28.2° N, 115.2° W) support the interpretation that Cretaceous rocks of western Baja California have moved farther northward than the 3° of latitude assignable to Neogene oblique rifting in the Gulf of California. Averaged Cretaceous paleomagnetic results from Cedros Island support 20 ± 10° of northward displacement and 14 ± 7° of clockwise rotation with respect to cratonic North America. Positive field stability tests from the Vizcaino terrane substantiate a mid-Cretaceous age for the high-temperature characteristic remanent magnetization in mid-Cretaceous strata. Therefore coincidence of characteristic magnetization directions and the expected Quaternary axial dipole direction is not due to post mid-Cretaceous remagnetization. A slump test performed on internally coherent, intrabasinal slump blocks within a paleontologically dated olistostrome demonstrates a mid-Cretaceous age of magnetization in the Valle Group. The in situ high-temperature natural remanent magnetization directions markedly diverge from the expected Quaternary axial dipole, indicating that the characteristic, high-temperature magnetization was acquired prior to intrabasinal slumping. Early acquisition of the characteristic magnetization is also supported by a regional attitude test involving three localities in coherent mid-Cretaceous Valle Group strata. Paleomagnetic inclinations in mudstone are not different from those in sandstone, indicating that burial compaction did not bias the results toward shallow inclinations in the Vizcaino terrane.

  18. Terrane accumulation and collapse in central Europe: seismic and rheological constraints

    Science.gov (United States)

    Meissner, R.

    1999-05-01

    An attempt is made to compare the tectonic units and their evolution in central Europe with the deep seismic velocity structure and patterns of reflectivity. Caledonian and Variscan terrane accretion and orogenic collapse dominate the tectonic development in central and western Europe and have left their marks in a distinct velocity structure and crustal thickness as well as in the various reflectivity patterns. Whereas the memory of old collisional structures is still preserved in the rigid upper crust, collapse processes have formed and modified the lower crust. They have generally created rejuvenated, thin crusts with shallow Mohos. In the Variscan internides, the center of collision and post-orogenic heat pulses, the lower crust developed strong and thick seismic lamellae, the (cooler) externides show a thrust and shear pattern in the whole crust, and the North German Basin experienced large mafic intrusions in the lower crust and developed a high-velocity structure with only very thin lamellae on top of the Moho. The various kinds of reflectivity patterns in the lithosphere can be explained by a thermo-rheological model from terrane collision, with crustal thickening to collapse in a hot, post-orogenic setting.

  19. Tectonic superposition of the Kurosegawa Terrane upon the Sanbagawa metamorphic belt in eastern Shikoku, southwest Japan

    International Nuclear Information System (INIS)

    Suzuki, Hisashi; Isozaki, Yukio; Itaya, Tetsumaru.

    1990-01-01

    Weakly metamorphosed pre-Cenozoic accretionary complex in the northern part of the Chichibu Belt in Kamikatsu Town, eastern Shikoku, consists of two distinct geologic units; the Northern Unit and Southern Unit. The Northern Unit is composed mainly of phyllitic pelites and basic tuff with allochthonous blocks of chert and limestone, and possesses mineral paragenesis of the glaucophane schist facies. The Southern Unit is composed mainly of phyllitic pelites with allochthonous blocks of sandstone, limestone, massive green rocks, and chert, and possesses mineral paragenesis of the pumpellyite-actinolite facies. The Southern Unit tectonically overlies the Northern Univ by the south-dipping Jiganji Fault. K-Ar ages were dated for the recrystallized white micas from 11 samples of pelites and basic tuff in the Northern Unit, and from 6 samples of pelites in the Southern Unit. The K-Ar ages of the samples from the Northern Unit range in 129-112 Ma, and those from the Southern Unit in 225-194 Ma. In terms of metamorphic ages, the Northern Unit and Southern Unit are referred to the constituents of the Sanbagawa Metamorphic Belt, and to those of the Kurosegawa Terrane, respectively. Thus, tectonic superposition of these two units in the study area suggests that the Kurosegawa Terrane occurs in a higher structural position over the Sanbagawa Metamorphic Belt in eastern Shikoku. (author)

  20. Mineralogy and mineral chemistry of rare-metal pegmatites at Abu Rusheid granitic gneisses, South Eastern Desert, Egypt

    Directory of Open Access Journals (Sweden)

    Mohamed Fahmy Raslan

    2011-12-01

    Full Text Available The Abu Rushied area, situated in the South Eastern Desert of Egypt is a distinctive occurrence of economically important rare-metal mineralization where the host rocks are represented by granitic gneisses. Correspondingly, mineralogical and geochemical investigation of pegmatites pockets scattered within Abu Rusheid granitic gneisses revealed the presence of Hf-zircon, ferrocolumbite and uranyl silicate minerals (uranophane and kasolite. Electronmicroprobe analyses revealed the presence of Nb-Ta multioxide minerals (ishikawaite, uranopyrochlore, and fergusonite, uraninite, thorite and cassiterite as numerous inclusions in the recorded Hf-zircon and ferrocolumbite minerals.Abu Rusheid pegmatites are found as small and large bodies that occur as simple and complex (zoned pegmatites.Abu Rusheid rare-metal pegmatites occur as steeply dipping bodies of variable size, ranging from 1 to 5 m in width and 10 to 50 m in length. The zoned pegmatites are composed of wall zone of coarser granitic gneisses, intermediated zone of K-feldspar and pocket of mica (muscovite and biotite, and core of quartz and pocket ofmica with lenses of rare metals.The zircon is of bipyramidal to typical octahedral form and short prisms. Because the zircon of the investigated Abu Rushied pegmatite frequently contains hafnium in amounts ranging between 2.31 and 11.11%, the studied zircon was designated as Hf-rich zircon. This zircon commonly exhibits a normal zoning with rims consistentlyhigher in Hf than cores. The bright areas in the crystal either in core or rim showed a remarkable enrichment in hafnium content (8.83–11.11% with respect to the dark zones (3.19%. The investigated ferroclumbite commonly exhibits zoning; the dark zone is low in the Ta and U but the light zone is enriched in Ta (13% and U (1%. EMPAanalyses indicate the chemical composition of ishikawaite with U ranging from 0.68 to 0.79 per formula unit.Uranopyrochlore species has dominant uranium in the A

  1. Contrasting styles of sedimentation and deformation in the Chugach Terrane accretionary complex, south-central Alaska

    Science.gov (United States)

    Amato, J. M.; Pavlis, T. L.; Worthman, C.; Kochelek, E.; Day, E. M.; Clift, P. D.; Hecker, J.

    2011-12-01

    In southeast Alaska the Chugach terrane represents an accretionary complex associated with several arcs active at 200-65 Ma. This lithostratigraphic unit consists of blueschists with Early Jurassic metamorphic ages and uncertain depositional ages; the Jurassic-Cretaceous McHugh Complex; and the Late Cretaceous Valdez Group. Detrital zircon ages from densely sampled transects reveals patterns in the assembly of the complex. Blueschists are almost totally barren of zircon, suggesting protoliths derived from mafic-intermediate volcanic protoliths far from a continental source. There is an age gap between the blueschists and the McHugh complex interpreted to be caused by an episode of tectonic erosion. The McHugh Complex is two separate units that are lithologically and geochronologically distinct. The older McHugh is a melange is dominated by stratally disrupted volcanic rocks, chert, and argillite. The oldest McHugh rocks have maximum depositional ages (MDA) of 177-150 Ma at Seldovia and 157-145 Ma at Turnagain Arm; the lack of older rocks at Turnagain Arm suggests removal of structural section by faulting. The MDAs of the older McHugh rocks do not decrease progressively away from the arc. There is a 45 m.y. gap in MDA between the older McHugh and the Late Cretaceous McHugh rocks. The younger McHugh rocks are dominated by volcanogenic sandstone and coarse conglomerate and MDA decreases from 100 Ma near the boundary with the older McHugh mesomelange to 85 Ma near the Valdez Group. The Valdez Group consists of coherently bedded turbidites with a MDA range of 85-60 Ma that decreases progressively outboard of the arc source. A sample from the Orca Group of the Prince William terrane is lithologically similar to the Valdez Group and there is no gap in MDA between Valdez and Orca Groups. 55 Ma dikes cut the McHugh and Valdez Groups in the western Chugach and Kenai Mountains. The oldest units of the Chugach terrane are the most deformed, with deformation and metamorphism

  2. Gamma-ray spectrometry of granitic suites of the Paranaguá Terrane, Southern Brazil

    Science.gov (United States)

    Weihermann, Jessica Derkacz; Ferreira, Francisco José Fonseca; Cury, Leonardo Fadel; da Silveira, Claudinei Taborda

    2016-09-01

    The Paranaguá Terrane, located in the coastal portion of the states of Santa Catarina, Paraná and São Paulo in Southern Brazil is a crustal segment constituted mainly by an igneous complex, with a variety of granitic rocks inserted into the Serra do Mar ridge. The average altitude is approximately 1200 m above sea level, with peaks of up to 1800 m. Due to the difficulty of accessing the area, a shortage of outcrops and the thick weathering mantle, this terrane is understudied. This research aims to evaluate the gamma-ray spectrometry data of the granitic suites of the Paranaguá Terrane, in correspondence with the geological, petrographical, lithogeochemical, relief and mass movement information available in the literature. Aerogeophysical data were acquired along north-south lines spaced at 500 m, with a mean terrain clearance of 100 m. These data cover potassium (K, %), equivalent in thorium (eTh, ppm) and equivalent in uranium (eU, ppm). After performing a critical analysis of the data, basic (K, eU, eTh) and ternary (R-K/G-eTh/B-eU) maps were generated and then superimposed on the digital elevation model (DEM). The investigation of the radionuclide mobility across the relief and weathering mantle consisted of an analysis of the schematic profiles of elevation related with each radionuclide; a comparison of the K, eU and eTh maps with their 3D correspondents; and the study of mass movements registered in the region. A statistical comparison of lithogeochemical (K, U, Th) and geophysical (K, eU, eTh) data showed consistency in all the granitic suites studied (Morro Inglês, Rio do Poço and Canavieiras-Estrela). Through gamma-ray spectrometry, it was possible to establish relationships between scars (from mass movements) and the gamma-ray responses as well as the radionuclide mobility and the relief and to map the granitic bodies.

  3. Cretaceous–Eocene provenance connections between the Palawan Continental Terrane and the northern South China Sea margin

    NARCIS (Netherlands)

    Shao, Lei; Cao, Licheng; Qiao, Peijun; Zhang, Xiangtao; Li, Qianyu; van Hinsbergen, Douwe J.J.

    2017-01-01

    The plate kinematic history of the South China Sea opening is key to reconstructing how the Mesozoic configuration of Panthalassa and Tethyan subduction systems evolved into today's complex Southeast Asian tectonic collage. The South China Sea is currently flanked by the Palawan Continental Terrane

  4. Paleozoic subduction complex and Paleozoic-Mesozoic island-arc volcano-plutonic assemblages in the northern Sierra terrane

    Science.gov (United States)

    Hanson, Richard E.; Girty, Gary H.; Harwood, David S.; Schweickert, Richard A.

    2000-01-01

    This field trip provides an overview of the stratigraphic and structural evolution of the northern Sierra terrane, which forms a significant part of the wall rocks on the western side of the later Mesozoic Sierra Nevada batholith in California. The terrane consists of a pre-Late Devonian subduction complex (Shoo Fly Complex) overlain by submarine arc-related deposits that record the evolution of three separate island-arc systems in the Late Sevonian-Early Mississippian, Permian, and Late Triassic-Jurassic. The two Paleozoic are packages and the underlying Shoo Fly Complex have an important bearing on plate-tectonic processes affecting the convergent margin outboard of the Paleozoic Cordilleran miogeocline, although their original paleogeographic relations to North America are controversial. The third arc package represents an overlap assemblage that ties the terrane to North America by the Late Triassic and helps constrain the nature and timing of Mesozoic orogenesis. Several of the field-trip stops examine the record of pre-Late Devonian subduction contained in the Shoo Fly Complex, as well as the paleovolcanology of the overlying Devonian to Jurassic arc rocks. Excellent glaciated exposures provide the opportunity to study a cross section through a tilted Devonian volcano-plutonic association. Additional stops focus on plutonic rocks emplaced during the Middle Jurassic arc magmatism in the terrane, and during the main pulse of Cretaceous magmatism in the Sierra Nevada batholith to the east.

  5. Microprobe monazite constraints for and early (ca. 790 Ma) Braziliano orogeny: The Embu Terrane, southeastern Brazil

    International Nuclear Information System (INIS)

    Vlach, Silvio R.F

    2001-01-01

    The evolution of the Mantiqueira Orogenetic System, Southeastern Brazil, comprises discrete episodes of tectonic collage and docking of remnants of Rodinia break-up in the borders of the Sao Francisco Craton. This system is related to the closure of the Adamastor ocean and assemblage of the western Gondwana super-continent during Neoproterozoic times (ca. 610-530 Ma, Brito Neves et al., 1999; Campos Neto, 2000). This report presents monazite microprobe dating results for metassediments from the Embu Complex, an important lithological unit from the Ribeira Belt, currently included in the Juiz de Fora terrane, a unit added to the Sao Francisco Craton at ca. 600-580 Ma. (Campos Neto, 2000). The age results unravel a main metamorphic episode and related orogeny at ca. 790 Ma and bring new insights concerning the agglutination of Gondwana in this region during the Neoproterozoic (au)

  6. Paleointensity determination on Neoarchaean dikes within the Vodlozerskii terrane of the Karelian craton

    Science.gov (United States)

    Shcherbakova, V. V.; Lubnina, N. V.; Shcherbakov, V. P.; Zhidkov, G. V.; Tsel'movich, V. A.

    2017-09-01

    The results of paleomagnetic studies and paleointensity determinations from two Neoarchaean Shala dikes with an age of 2504 Ma, located within the Vodlozerskii terrane of the Karelian craton, are presented. The characteristic components of primary magnetization with shallow inclinations I = -5.7 and 1.9 are revealed; the reliability of the determinations is supported by two contact tests. High paleointensity values are obtained by the Thellier-Coe and Wilson techniques. The calculated values of the virtual dipole moment (11.5 and 13.8) × 1022 A m2 are noticeably higher than the present value of 7.8 × 1022 A m2. Our results, in combination with the previous data presented in the world database, support the hypothesized existence of a period of high paleointensity in the Late Archaean-Early Proterozoic.

  7. kepler's dark worlds: A low albedo for an ensemble of Neptunian and Terran exoplanets

    Science.gov (United States)

    Jansen, Tiffany; Kipping, David

    2018-05-01

    Photometric phase curves provide an important window onto exoplanetary atmospheres and potentially even their surfaces. With similar amplitudes to occultations but far longer baselines, they have a higher sensitivity to planetary photons at the expense of a more challenging data reduction in terms of long-term stability. In this work, we introduce a novel non-parametric algorithm dubbed phasma to produce clean, robust exoplanet phase curves and apply it to 115 Neptunian and 50 Terran exoplanets observed by kepler. We stack the signals to further improve signal-to-noise, and measure an average Neptunian albedo of Ag greenhouse effect, our work implies that kepler's solid planets are unlikely to resemble cloudy Venusian analogs, but rather dark Mercurian rocks.

  8. Are turtleback fault surfaces common structural elements of highly extended terranes?

    Science.gov (United States)

    Çemen, Ibrahim; Tekeli, Okan; Seyitoğlu, Gűrol; Isik, Veysel

    2005-12-01

    The Death Valley region of the U.S.A. contains three topographic surfaces resembling the carapace of a turtle. These three surfaces are well exposed along the Black Mountain front and are named the Badwater, Copper Canyon, and Mormon Point Turtlebacks. It is widely accepted that the turtlebacks are also detachment surfaces that separate brittlely deformed Cenozoic volcanic and sedimentary rocks of the hanging wall from the strongly mylonitic, ductilely deformed pre-Cenozoic rocks of the footwall. We have found a turtleback-like detachment surface along the southern margin of the Alasehir (Gediz) Graben in western Anatolia, Turkey. This surface qualifies as a turtleback fault surface because it (a) is overall convex-upward and (b) separates brittlely deformed hanging wall Cenozoic sedimentary rocks from the ductilely to brittlely deformed, strongly mylonitic pre-Cenozoic footwall rocks. The surface, named here Horzum Turtleback, contains striations that overprint mylonitic stretching lineations indicating top to the NE sense of shear. This suggests that the northeasterly directed Cenozoic extension in the region resulted in a ductile deformation at depth and as the crust isostatically adjusted to the removal of the rocks in the hanging wall of the detachment fault, the ductilely deformed mylonitic rocks of the footwall were brought to shallower depths where they were brittlely deformed. The turtleback surfaces have been considered unique to the Death Valley region, although detachment surfaces, rollover folds, and other extensional structures have been well observed in other extended terranes of the world. The presence of a turtleback fault surface in western Anatolia, Turkey, suggests that the turtleback faults may be common structural features of highly extended terranes.

  9. Assessment of Blasting Performance Using Electronic Vis-à-Vis Shock Tube Detonators in Strong Garnet Biotite Sillimanite Gneiss Formations

    Science.gov (United States)

    Sharma, Suresh Kumar; Rai, Piyush

    2016-04-01

    This paper presents a comparative investigation of the shock tube and electronic detonating systems practised in bench blasting. The blast trials were conducted on overburden rocks of Garnet Biotite Sillimanite Gneiss formations in one of the largest metalliferous mine of India. The study revealed that the choice of detonating system was crucial in deciding the fragment size and its distribution within the blasted muck-piles. The fragment size and its distribution affected the digging rate of excavators. Also, the shape of the blasted muck-pile was found to be related to the degree of fragmentation. From the present work, it may be inferred that in electronic detonation system, timely release of explosive energy resulted in better overall blasting performance. Hence, the precision in delay time must be considered in designing blast rounds in such overburden rock formations. State-of-art image analysis, GPS based muck-pile profile plotting techniques were rigorously used in the investigation. The study revealed that a mean fragment size (K50) value for shock tube detonated blasts (0.55-0.59 m) was higher than that of electronically detonated blasts (0.43-0.45 m). The digging rate of designated shovels (34 m3) with electronically detonated blasts was consistently more than 5000 t/h, which was almost 13 % higher in comparison to shock tube detonated blasts. Furthermore, favourable muck-pile shapes were witnessed in electronically detonated blasts from the observations made on the dozer performance.

  10. Geophysical modeling of the northern Appalachian Brompton-Cameron, Central Maine, and Avalon terranes under the New Jersey Coastal Plain

    Science.gov (United States)

    Maguire, T.J.; Sheridan, R.E.; Volkert, R.A.

    2004-01-01

    A regional terrane map of the New Jersey Coastal Plain basement was constructed using seismic, drilling, gravity and magnetic data. The Brompton-Cameron and Central Maine terranes were coalesced as one volcanic island arc terrane before obducting onto Laurentian, Grenville age, continental crust in the Taconian orogeny [Rankin, D.W., 1994. Continental margin of the eastern United States: past and present. In: Speed, R.C., (Ed.), Phanerozoic Evolution of North American Continent-Ocean Transitions. DNAG Continent-Ocean Transect Volume. Geological Society of America, Boulder, Colorado, pp. 129-218]. Volcanic island-arc rocks of the Avalon terrane are in contact with Central Maine terrane rocks in southern Connecticut where the latter are overthrust onto the Brompton-Cameron terrane, which is thrust over Laurentian basement. Similarities of these allochthonous island arc terranes (Brompton-Cameron, Central Maine, Avalon) in lithology, fauna and age suggest that they are faulted segments of the margin of one major late Precambrian to early Paleozoic, high latitude peri-Gondwana island arc designated as "Avalonia", which collided with Laurentia in the early to middle Paleozoic. The Brompton Cameron, Central Maine, and Avalon terranes are projected as the basement under the eastern New Jersey Coastal Plain based on drill core samples of metamorphic rocks of active margin/magmatic arc origin. A seismic reflection profile across the New York Bight traces the gentle dipping (approximately 20 degrees) Cameron's Line Taconian suture southeast beneath allochthonous Avalon and other terranes to a 4 sec TWTT depth (approximately 9 km) where the Avalonian rocks are over Laurentian crust. Gentle up-plunge (approximately 5 degrees) projections to the southwest bring the Laurentian Grenville age basement and the drift-stage early Paleozoic cover rocks to windows in Burlington Co. at approximately 1 km depth and Cape May Co. at approximately 2 km depths. The antiformal Shellburne

  11. Geology and metallogeny of the Ar Rayn terrane, eastern Arabian shield: Evolution of a Neoproterozoic continental-margin arc during assembly of Gondwana within the East African orogen

    Science.gov (United States)

    Doebrich, J.L.; Al-Jehani, A. M.; Siddiqui, A.A.; Hayes, T.S.; Wooden, J.L.; Johnson, P.R.

    2007-01-01

    The Neoproterozoic Ar Rayn terrane is exposed along the eastern margin of the Arabian shield. The terrane is bounded on the west by the Ad Dawadimi terrane across the Al Amar fault zone (AAF), and is nonconformably overlain on the east by Phanerozoic sedimentary rocks. The terrane is composed of a magmatic arc complex and syn- to post-orogenic intrusions. The layered rocks of the arc, the Al Amar group (>689 Ma to ???625 Ma), consist of tholeiitic to calc-alkaline basaltic to rhyolitic volcanic and volcaniclastic rocks with subordinate tuffaceous sedimentary rocks and carbonates, and are divided into an eastern and western sequence. Plutonic rocks of the terrane form three distinct lithogeochemical groups: (1) low-Al trondhjemite-tonalite-granodiorite (TTG) of arc affinity (632-616 Ma) in the western part of the terrane, (2) high-Al TTG/adakite of arc affinity (689-617 Ma) in the central and eastern part of the terrane, and (3) syn- to post-orogenic alkali granite (607-583 Ma). West-dipping subduction along a trench east of the terrane is inferred from high-Al TTG/adakite emplaced east of low-Al TTG. The Ar Rayn terrane contains significant resources in epithermal Au-Ag-Zn-Cu-barite, enigmatic stratiform volcanic-hosted Khnaiguiyah-type Zn-Cu-Fe-Mn, and orogenic Au vein deposits, and the potential for significant resources in Fe-oxide Cu-Au (IOCG), and porphyry Cu deposits. Khnaiguiyah-type deposits formed before or during early deformation of the Al Amar group eastern sequence. Epithermal and porphyry deposits formed proximal to volcanic centers in Al Amar group western sequence. IOCG deposits are largely structurally controlled and hosted by group-1 intrusions and Al Amar group volcanic rocks in the western part of the terrane. Orogenic gold veins are largely associated with north-striking faults, particularly in and near the AAF, and are presumably related to amalgamation of the Ar Rayn and Ad Dawadimi terranes. Geologic, structural, and metallogenic

  12. U-Pb dating of deformed mafic dyke and host gneiss: implications for understanding reworking processes on the western margin of the Archaean U3o8 Block, NE Sao Francisco Craton, Brazil

    International Nuclear Information System (INIS)

    Oliveira, Elson Paiva

    2000-01-01

    U-Pb ages of deformed mafic dyke and host migmatitic grey gneiss from the transition zone between the Archaen Uaua Block and the Caldeirao Belt are presented. Titanites from the metamorphic dyke's margin and zircons from the gneiss were dated at 2,039 ± 2 Ma and 2,956 ± 39 Ma, respectively. The Sm-Nd data (T DM =2,965 Ma and ε Nd(t) =1.69) on the gneiss, coupled with the U-Pb data on both dyke and gneiss, suggest than an Archaen granodioritic batholith, probably originated at an andean-type continental margin, was intruded by mafic dykes, and subsequently was reworked during the Paleoproterozoic collisional event associated with the development of the Salvador-Curaca Orogen. (author)

  13. Time-constrained project scheduling with adjacent resources

    NARCIS (Netherlands)

    Hurink, Johann L.; Kok, A.L.; Paulus, J.J.; Schutten, Johannes M.J.

    We develop a decomposition method for the Time-Constrained Project Scheduling Problem (TCPSP) with adjacent resources. For adjacent resources the resource units are ordered and the units assigned to a job have to be adjacent. On top of that, adjacent resources are not required by single jobs, but by

  14. Time-constrained project scheduling with adjacent resources

    NARCIS (Netherlands)

    Hurink, Johann L.; Kok, A.L.; Paulus, J.J.; Schutten, Johannes M.J.

    2008-01-01

    We develop a decomposition method for the Time-Constrained Project Scheduling Problem (TCPSP) with Adjacent Resources. For adjacent resources the resource units are ordered and the units assigned to a job have to be adjacent. On top of that, adjacent resources are not required by single jobs, but by

  15. Himalayan gneiss dome formation in the middle crust and exhumation by normal faulting: New geochronology of Gianbul dome, northwestern India

    Science.gov (United States)

    Horton, Forrest; Lee, Jeffrey; Hacker, Bradley; Bowman-Kamaha'o, Meilani; Cosca, Michael A.

    2015-01-01

    A general lack of consensus about the origin of Himalayan gneiss domes hinders accurate thermomechanical modeling of the orogen. To test whether doming resulted from tectonic contraction (e.g., thrust duplex formation, antiformal bending above a thrust ramp, etc.), channel flow, or via the buoyant rise of anatectic melts, this study investigates the depth and timing of doming processes for Gianbul dome in the western Himalaya. The dome is composed of Greater Himalayan Sequence migmatite, Paleozoic orthogneiss, and metasedimentary rock cut by multiple generations of leucogranite dikes. These rocks record a major penetrative D2 deformational event characterized by a domed foliation and associated NE-SW–trending stretching lineation, and they are flanked by the top-down-to-the-SW (normal-sense) Khanjar shear zone and the top-down-to-the-NE (normal sense) Zanskar shear zone (the western equivalent of the South Tibetan detachment system). Monazite U/Th-Pb geochronology records (1) Paleozoic emplacement of the Kade orthogneiss and associated granite dikes; (2) prograde Barrovian metamorphism from 37 to 33 Ma; (3) doming driven by upper-crustal extension and positive buoyancy of decompression melts between 26 and 22 Ma; and (4) the injection of anatectic melts into the upper levels of the dome—neutralizing the effects of melt buoyancy and potentially adding strength to the host rock—by ca. 22.6 Ma on the southwestern flank and ca. 21 Ma on the northeastern flank. As shown by a northeastward decrease in 40Ar/39Ar muscovite dates from 22.4 to 20.2 Ma, ductile normal-sense displacement within the Zanskar shear zone ended by ca. 22 Ma, after which the Gianbul dome was exhumed as part of a rigid footwall block below the brittle Zanskar normal fault, tilting an estimated 5°–10°SW into its present orientation.

  16. Paleomagnetic contributions to the Klamath Mountains terrane puzzle-a new piece from the Ironside Mountain batholith, northern California

    Science.gov (United States)

    Mankinen, Edward A.; Gromme, C. Sherman; Irwin, W. Porter

    2013-01-01

    We obtained paleomagnetic samples from six sites within the Middle Jurassic Ironside Mountain batholith (~170 Ma), which constitutes the structurally lowest part of the Western Hayfork terrane, in the Klamath Mountains province of northern California and southern Oregon. Structural attitudes measured in the coeval Hayfork Bally Meta-andesite were used to correct paleomagnetic data from the batholith. Comparing the corrected paleomagnetic pole with a 170-Ma reference pole for North America indicates 73.5° ± 10.6° of clockwise rotation relative to the craton. Nearly one-half of this rotation may have occurred before the terrane accreted to the composite Klamath province at ~168 Ma. No latitudinal displacement of the batholith was detected.

  17. Lithospheric discontinuities beneath the U.S. Midcontinent - signatures of Proterozoic terrane accretion and failed rifting

    Science.gov (United States)

    Chen, Chen; Gilbert, Hersh; Fischer, Karen M.; Andronicos, Christopher L.; Pavlis, Gary L.; Hamburger, Michael W.; Marshak, Stephen; Larson, Timothy; Yang, Xiaotao

    2018-01-01

    Seismic discontinuities between the Moho and the inferred lithosphere-asthenosphere boundary (LAB) are known as mid-lithospheric discontinuities (MLDs) and have been ascribed to a variety of phenomena that are critical to understanding lithospheric growth and evolution. In this study, we used S-to-P converted waves recorded by the USArray Transportable Array and the OIINK (Ozarks-Illinois-Indiana-Kentucky) Flexible Array to investigate lithospheric structure beneath the central U.S. This region, a portion of North America's cratonic platform, provides an opportunity to explore how terrane accretion, cratonization, and subsequent rifting may have influenced lithospheric structure. The 3D common conversion point (CCP) volume produced by stacking back-projected Sp receiver functions reveals a general absence of negative converted phases at the depths of the LAB across much of the central U.S. This observation suggests a gradual velocity decrease between the lithosphere and asthenosphere. Within the lithosphere, the CCP stacks display negative arrivals at depths between 65 km and 125 km. We interpret these as MLDs resulting from the top of a layer of crystallized melts (sill-like igneous intrusions) or otherwise chemically modified lithosphere that is enriched in water and/or hydrous minerals. Chemical modification in this manner would cause a weak layer in the lithosphere that marks the MLDs. The depth and amplitude of negative MLD phases vary significantly both within and between the physiographic provinces of the midcontinent. Double, or overlapping, MLDs can be seen along Precambrian terrane boundaries and appear to result from stacked or imbricated lithospheric blocks. A prominent negative Sp phase can be clearly identified at 80 km depth within the Reelfoot Rift. This arrival aligns with the top of a zone of low shear-wave velocities, which suggests that it marks an unusually shallow seismic LAB for the midcontinent. This boundary would correspond to the top of a

  18. North America as an exotic terrane'' and the origin of the Appalachian--Andean Mountain system

    Energy Technology Data Exchange (ETDEWEB)

    Dalziel, I.W.D; Gahagan, L.M. (Univ. of Texas, Austin, TX (United States). Inst. for Geophysics); Dalla Salda, L.H. (Univ. Nacional de La Plata, La Plata (Argentina). Centro de Investigaciones Geologicas)

    1992-01-01

    North America was sutured to Gondwana in the terminal Alleghanian event of Appalachian orogenesis, thus completing the late Paleozoic assembly of Pangea. The suggestion that the Pacific margins of East Antarctica-Australia and Laurentia may have been juxtaposed during the Neoproterozoic prompts reevaluation of the widely held assumptions that the ancestral Appalachian margin rifted from northwestern Africa during the earliest Paleozoic opening of Iapetus, and remained juxtaposed to that margin, even though widely separated from it at times, until the assembly of Pangea. The lower Paleozoic carbonate platform of northwestern Argentina has been known for a long time to contain Olenellid trilobites of the Pacific or Columbian realm. Although normally regarded as some kind of far-travelled terrane that originated along the Appalachian margin of Laurentia, it has recently been interpreted as a fragment detached from the Ouachita embayment of Laurentia following Taconic-Famatinian collision with Gondwana during the Ordovician. The Oaxaca terrane of Mexico, on the other hand, contains a Tremadocian trilobite fauna of Argentine-Bolivian affinities, and appears to have been detached from Gondwana following the same collision. The Wilson cycle'' of Iapetus ocean basin opening and closing along the Appalachian and Andean orogens may have involved more than one such continental collision during clockwise drift of Laurentia around South America following late Neoproterozoic to earliest Cambrian separation. Together with the collisions of baltic and smaller terranes with Laurentia, this could explain the protracted Paleozoic orogenic history of both the Appalachian and proto-Andean orogens.

  19. Terrane Boundary Geophysical Signatures in Northwest Panay, Philippines: Results from Gravity, Seismic Refraction and Electrical Resistivity Investigations

    Directory of Open Access Journals (Sweden)

    Jillian Aira S. Gabo

    2015-01-01

    Full Text Available Northwest Panay consists of two terranes that form part of the Central Philippine collision zone: Buruanga Peninsula and Antique Range. The Buruanga Peninsula consists of a Jurassic chert-clastic-limestone sequence, typical of oceanic plate stratigraphy of the Palawan Micro-continental Block. The Antique Range is characterized by Antique Ophiolite Complex peridotites and Miocene volcanic and clastic rocks, representing obducted oceanic crust that serves as the oceanic leading edge of the collision with the Philippine Mobile Belt. The Nabas Fault is identified as the boundary between the two terranes. This study employed the gravity method to characterize the Northwest Panay subsurface structure. Results indicate higher Bouguer anomaly values for Buruanga Peninsula than those for Antique Range, separated by a sudden decrease in gravity values toward the east-southeast (ESE direction. Forward gravity data modeling indicates the presence of an underlying basaltic subducted slab in the Buruanga Peninsula. Furthermore, the Nabas Fault is characterized as an east-dipping thrust structure formed by Buruanga Peninsula basement leading edge subduction beneath Antique Range. Additional geophysical constraints were provided by shallow seismic refraction and electrical resistivity surveys. Results from both methods delineated the shallow subsurface signature of the Nabas Fault buried beneath alluvium deposits. The gravity, seismic refraction and electrical resistivity methods were consistent in identifying the Nabas Fault as the terrane boundary between the Buruanga Peninsula and the Antique Range. The three geophysical methods helped constrain the subsurface configuration in Northwest Panay.

  20. Spondylolisthesis adjacent to a cervical disc arthroplasty does not increase the risk of adjacent level degeneration.

    Science.gov (United States)

    Kieser, David Christopher; Cawley, Derek Thomas; Roscop, Cecile; Mazas, Simon; Coudert, Pierre; Boissiere, Louis; Obeid, Ibrahim; Vital, Jean-Marc; Pointillart, Vincent; Gille, Olivier

    2018-03-31

    To understand whether a spondylolisthesis in the sub-axial spine cranial to a cervical disc arthroplasty (CDA) construes a risk of adjacent level disease (ALD). A retrospective review of 164 patients with a minimum 5-year follow-up of a cervical disc arthroplasty was performed. Multi-level surgeries, including hybrid procedures, were included. Multiple implant types were included. The two inter-vertebral discs (IVD) cranial of the CDA were monitored for evidence of radiologic degeneration using the Kettler criteria. The rate of ALD in CDA found in this series was 17.8%, with most affecting the immediately adjacent IVD (27.4 and 7.6%, respectively p = 0.000). Pre-operative mild spondylolisthesis adjacent to a planned CDA was not found to be a risk factor for ALD within 5 years. Those with a degenerative spondylolisthesis are at higher risk of ALD (33%) than those with a non-degenerative cause for their spondylolisthesis (11%). Post-operative CDA alignment, ROM or induced spondylolisthesis do not affect the rate of ALD in those with an adjacent spondylolisthesis. Patients with ALD experience significantly worse 5-year pain and functional outcomes than those unaffected by ALD. A pre-operatively identified mild spondylolisthesis in the sub-axial spine cranially adjacent to a planned CDA is not a risk factor for ALD within 5 years. These slides can be retrieved under Electronic Supplementary Material.

  1. Post-peak metamorphic evolution of the Sumdo eclogite from the Lhasa terrane of southeast Tibet

    Science.gov (United States)

    Cao, Dadi; Cheng, Hao; Zhang, Lingmin; Wang, Ke

    2017-08-01

    A reconstruction of the pressure-temperature-time (P-T-t) path of high-pressure eclogite-facies rocks in subduction zones may reveal important information about the tectono-metamorphic processes that occur at great depths along the plate interface. The majority of studies have focused on prograde to peak metamorphism of these rocks, whereas after-peak metamorphism has received less attention. Herein, we present a detailed petrological, pseudosection modeling and radiometric dating study of a retrograded eclogite sample from the Sumdo ultrahigh pressure belt of the Lhasa terrane, Tibet. Mineral chemical variations, textural discontinuities and thermodynamic modeling suggest that the eclogite underwent an exhumation-heating period. Petrographic observations and phase equilibria modeling suggest that the garnet cores formed at the pressure peak (∼2.5 GPa and ∼520 °C) within the lawsonite eclogite-facies and garnet rims (∼1.5 GPa and spans an interval of ∼7 million years, which is a minimum estimate of the duration of the eclogite-facies metamorphism of the Sumdo eclogite.

  2. UTE park group and other meso proterozoic units of the Nico Perez terrane: Rodina connecting

    International Nuclear Information System (INIS)

    Gaucher, C; Chemale, F.; Bossi, J.; Sial, A.; Chiglino, L.

    2010-01-01

    The Parque UTE Group is a volcano sedimentary succession metamorphosed in green schist facies, comprising (from base to top): the Canada Espinillo Formation (prasinites, pelites, andesite s), the Mina Valencia Formation (dolostones, limestones, marls) and the Cerro del Mast il Formation (black pelites, limestones, acid tuffs). Thickness of the GPU exceeds 2.5 km; base and top are not exposed. U-Pb zircon ages for basic magmatic rocks at the base and rhyolites at the top yielded 1492±4 and 1429±21 Ma, respectively. 13C values of carbonates of the Pug are characterized by a plateau at +1‰ VPDB, bracketed between two negative excursions.These values are consistent with an early Mesoproterozoic depositional age. Detrital zircon age spectra show that the source area of the GPU was the Nico Perez Terrane, being thus native to the Rio de la Plata Craton (Rpc). A Mesoproterozoic tectonic event at 1.25 Ga, recorded at both sides of the Sarandi del Yi mega shear, is discussed. New U-Pb zircon ages are presented for the La China Complex at its type area, where a schistosity N60W cuts the metamorphic banding and is parallel to thrusts dated K-Ar at 1253±32 Ma. The ages obtained are: 3096±45 Ma (main metamorphic event) and 1252 Ma (lower intercept). These data confirm the occurrence of a Grenvillian-aged tectonic event in Uruguay, suggesting that the RPC was part of the super continent Rodinia

  3. Protoliths of enigmatic Archaean gneisses established from zircon inclusion studies: Case study of the Caozhuang quartzite, E. Hebei, China

    Directory of Open Access Journals (Sweden)

    Allen P. Nutman

    2014-07-01

    Full Text Available A diverse suite of Archaean gneisses at Huangbaiyu village in the North China Craton, includes rare fuchsite-bearing (Cr-muscovite siliceous rocks – known as the Caozhuang quartzite. The Caozhuang quartzite is strongly deformed and locally mylonitic, with silica penetration and pegmatite veining common. It contains abundant 3880–3600 Ma and some Palaeoarchaean zircons. Because of its siliceous nature, the presence of fuchsite and its complex zircon age distribution, it has until now been accepted as a (mature quartzite. However, the Caozhuang quartzite sample studied here is feldspathic. The shape and cathodoluminescence petrography of the Caozhuang quartzite zircons show they resemble those found in immature detrital sedimentary rocks of local provenance or in Eoarchaean polyphase orthogneisses, and not those in mature quartzites. The Caozhuang quartzite intra-zircon mineral inclusions are dominated by quartz, with lesser biotite, apatite (7% and alkali-feldspar, and most inclusions are morphologically simple. A Neoarchaean orthogneiss from near Huangbaiyu displays morphologically simple inclusions with much more apatite (73%, as is typical for fresh calc-alkaline granitoids elsewhere. Zircons were also examined from a mature conglomerate quartzite clast and an immature feldspathic sandstone of the overlying weakly metamorphosed Mesoproterozoic Changcheng System. These zircons have oscillatory zoning, showing they were sourced from igneous rocks. The quartzite clast zircons contain only rare apatite inclusions (<1%, with domains with apatite habit now occupied by intergrowths of muscovite + quartz ± Fe-oxides ± baddeleyite. We interpret that these were once voids after apatite inclusions that had dissolved during Mesoproterozoic weathering, which were then filled with clays ± silica and then weakly metamorphosed. Zircons in the immature feldspathic sandstone show a greater amount of preserved apatite (11%, but with petrographic

  4. Petrological and geochemical features of the early Paleozoic granitic gneisses and iron ores in the Tianhu iron deposit, Eastern Tianshan, NW China: Implications for ore genesis

    Science.gov (United States)

    Zheng, Jiahao; Mao, Jingwen; Yang, Fuquan; Chai, Fengmei; Shen, Ping

    2017-08-01

    This paper reports whole-rock geochemical, zircon U-Pb and Hf isotopic data for ore-hosted granitic gneisses, mineral compositions of oxides, and sulfur isotopic data for sulfides in iron ores from the Tianhu deposit, central part of the Eastern Tianshan. Our results can provide crucial constraints on the genesis of granitic gneisses and early Paleozoic tectonic setting of the Eastern Tianshan. LA-ICP-MS U-Pb dating on magmatic zircons yielded weighted mean 206Pb/238U ages of 463 to 438 Ma, interpreted as the crystallization ages of the granitic protoliths and the formation ages of the Tianhu Group. Zircon U-Pb age of ore-hosted granitic gneiss (ca. 459 Ma) can provide reliable constrains on upper limit for iron mineralization age in the Tianhu deposit. Geochemical characteristics suggest that the protoliths of the Tianhu granitic gneisses are metaluminous to weakly peraluminous high-K calc-alkaline granitic rocks, exhibiting typical subduction-related features such as strong enrichment in LREE and LILE and depletion in HFSE. Zircon Hf isotopic compositions show a positive trend from 463 to 438 Ma, indicating that 460 Ma magmas came from both ancient and juvenile sources, whereas 438 Ma magmas involved more juvenile material. Some early Paleozoic granitoids were recently identified in the Eastern Tianshan with the ages between ca. 475 and ca. 425 Ma. The formation of these early Paleozoic granitoids was in response to subduction processes, suggesting that subduction of Junggar Ocean probably began in the Early Ordovician and lasted until Late Silurian. Pyrite and pyrrhotite in iron ores have δ34SCDT values from + 4.6 to + 15.7‰, which are consistent with the marine source, but inconsistent with the magmatic source or those involved evaporites in skarn iron deposit. Geological, geochemical, and isotopic data suggest that the Tianhu iron ores were formed by volcano-sedimentary processes in a subduction environment during the early Paleozoic time, and Tianhu is a

  5. Paleoproterozoic (ca. 1.8 Ga) arc magmatism in the Lützow-Holm Complex, East Antarctica: Implications for crustal growth and terrane assembly in erstwhile Gondwana fragments

    Science.gov (United States)

    Takahashi, Kazuki; Tsunogae, Toshiaki; Santosh, M.; Takamura, Yusuke; Tsutsumi, Yukiyasu

    2018-05-01

    lithological data from the region, suggest that the LHC can be divided into three units: Neoarchean (ca. 2.5 Ga) unit in the southern LHC (Shirase Orthogneiss or "Shirase microcontinent"), Neoproterozoic (ca. 1.0 Ga) unit in the northern LHC, and supracrustal unit in the central LHC with fragments of Paleoproterozoic (ca. 1.8 Ga) and minor Neoarchean (ca. 2.5 Ga) and Neoproterozoic (ca. 1.0 Ga) magmatic arcs. The 1.8 Ga arc magmatism inferred in this study has also been reported from adjacent Gondwana fragments such as the Highland Complex in Sri Lanka, and the Trivandrum and Nagercoil Blocks in southern India. Although the ca. 1.8 Ga arc-magmatic event is coeval in these regions, the Paleoproterozoic supracrustal unit in the central LHC may not be contiguous with those in the Highland Complex of Sri Lanka because recent studies have shown that the Vijayan Complex in Sri Lanka and the ca. 1.0 Ga northern LHC possibly were part of a single crustal unit (northern Lützow-Holm-Vijayan Complex) within the Kalahari Block. The supracrustal unit possibly marks part of a discrete suture formed by the collision of the ca. 2.5 Ga southern LHC (Shirase microcontinent) and the ca. 1.0 Ga northern Lützow-Holm-Vijayan Complex during the latest Neoproterozoic-Cambrian Gondwana amalgamation, which might be coeval with the collision of the Vijayan and Wanni Complexes and the formation of the Highland Complex in Sri Lanka. Our study provides new insights on crustal growth and terrane assembly in the ancient continental blocks of Gondwana.

  6. Combined U-Pb SHRIMP and Hf isotope study of the Late Paleozoic Yaminué Complex, Rio Negro Province, Argentina: Implications for the origin and evolution of the Patagonia composite terrane

    Directory of Open Access Journals (Sweden)

    Carlos J. Chernicoff

    2013-01-01

    Combining geological and isotope data, as well as geophysical models, we identify the Yaminué Complex within the La Esperanza-Yaminué crustal block flanked by two other, distinct crustal blocks: the Eastern block which forms part of the Patagonia terrane sensu stricto, located in the eastern Patagonian region, and the Western block forming part of the Southern Patagonia terrane. Their origins and timing of amalgamation to form the Patagonia composite terrane are also discussed.

  7. Recognition of the Kaweka Terrane in northern South Island, New Zealand : preliminary evidence from Rb-Sr metamorphic and U-Pb detrital zircon ages

    International Nuclear Information System (INIS)

    Adams, C.J.; Mortimer, N.; Campbell, H.J.; Griffin, W.L.

    2011-01-01

    Detrital zircon U-Pb ages and Rb-Sr metamorphic ages from low-grade Torlesse Supergroup metasedimentary rocks from North Canterbury and Marlborough provide preliminary evidence for a continuation of the Kaweka Terrane of the central North Island into the Torlesse Composite Terrane of the South Island. This would extend from the south side of the Wairau Fault in the upper Wairau River valley southwards to the Lake Tennyson and Lake Sumner areas, and as far as Hawarden. Rb-Sr ages indicate Jurassic metamorphism, 170±24 Ma, with initial 87 Sr/ 86 Sr ratios at that time 0.7073 ± 0.0007 i.e. similar to their North Island counterparts. These Kaweka Terrane rocks have detrital zircon ages that follow the distinctive pattern of the Torlesse rocks in general, i.e. substantial (>30%) Permian-Triassic and Precambrian-Early Palaeozoic groupings, but they also have minor youngest age components c. 175-165 Ma which constrain a maximum Early-Middle Jurassic depositional age. In detail, significant, older zircon components are Late Permian-Early Triassic (260-240 Ma) and Late Triassic (220-210 Ma), but the Precambrian-Early Palaeozoic detrital zircon ages are more scattered. The Kaweka Terrane thus forms a linear belt (c. 500 km) along the length of the Torlesse Composite Terrane in both North and South Islands. In the South Island it coincides with the Esk Head Belt, i.e. east of the Rakaia Terrane (Triassic-Late Permian) and west of the Pahau Terrane (Early Cretaceous-Late Jurassic). (author). 61 refs., 4 figs., 2 tabs.

  8. Park Volcanics, Murihiku Terrane, New Zealand : petrology, petrochemistry, and tectonic significance

    International Nuclear Information System (INIS)

    Coombs, D.S.; Cook, N.D.J.; Kawachi, Y.; Johnstone, R.D.; Gibson, I.L.

    1996-01-01

    The Late Triassic to Early Jurassic Park Volcanics Group comprises minor shallow intrusive and extrusive bodies emplaced during mainly marine sedimentation of the Murihiku Terrane, southern New Zealand. Gowan Andesite in western Southland and Glenham Porphyry andesites in eastern Southland are high-K andesites. Glassy examples have commonly lost K during alteration. Orthoclase contents of Or 3.6-3.7 in plagioclase phenocrysts at An 50 confirm the high-K nature of the melts at the time of phenocryst crystallisation. The Gowan andesites have higher Fe/Mg than the Glenham and related differences in minor element chemistry suggesting lower ∫O 2 during fractionation of the parent magma. Pinney Volcanics in western Southland are mostly high-K trachydacites but, like Glenham Porphyry, include minor rhyolite. Barnicoat Andesite in the Nelson area is medium-K olivine andesite, marginally tholeiitic in terms of its FeO*/MgO versus SiO 2 behaviour, but otherwise is typically calc-alkaline, as are the Gowan, Glenham, and Pinney. Analyses of pyroxenes (augites, orthopyroxenes, reaction rim and groundmass pigeonites) reveal xenocrysts recording an early stage of magma fractionation, slight iron enrichment in the andesite stage, and lowered Fe/Mg and increased Ca contents in augites of the most felsic rocks. Titanian tschermakite and titanian magnesio-tschermakite of deep-seated origin participated in fractionation leading to the Pinney Volcanics, and magnesio-hornblende, edenite, and biotite crystallised as minor late stage minerals following high-level emplacement of Gowan Andesite and siliceous Glenham Porphyry members. Low 87 Sr/ 86 Sr ratios (c. 0.7034-0.7037), REE and multi-element distribution patterns, and the mineralogical features collectively suggest fractionation of the andesites from parental basalt originating in an enriched mantle wedge above a subduction zone, with minimal contamination by continental crust. High-K andesites appear to be unknown in clearly

  9. Precambrian Terranes of African affinities in the southeastern part of Brazil and Uruguay

    International Nuclear Information System (INIS)

    Preciozzi, F.; Basei, M.; Siga Junior, H.; Sato, K.; Kaufuss, G.

    2006-01-01

    The interest in correlating terranes at opposite margins of the South Atlantic Ocean reflects a natural curiosity of both researchers who work in the eastern South-America and who study southwestern Africa. On a large scale scenario the geology of this region is characterized by a central portion composed of Neoproterozoic-Cambrian belts (Dom Feliciano, Kao ko, Damara, Gariep, Saldania) having on each side old gneissic-migmatitic terrains on both continents (Luis Alves, Rio de La Plata, Kalahari and Congo). In South America the Neoproterozoic Dom Feliciano Belt (DFB) predominates in the eastern part of the region and is internally organized according to three different crustal segments characterized, from southeast to northwest, by a Granite belt (deformed I-type medium to high calc-alkaline granites and alkaline granitoid rocks; a Schist belt (volcano-sedimentary rocks metamorphosed from green schist to amphibolite facies and intrusive granitoids), and a Fore land basin (anchimetamorphic sedimentary and volcanic rocks), the latter situated between the Schist belt and the Archean-Paleoproterozoic fore land. Despite discontinuously covered by younger sediments, the NS continuity of these three crustal segments is suggested by similar lithotypes, structural characteristics, ages and isotopic signature, as well as by the gravimetric data. The Major Gercino, Cordilheira, and Sierra Ballena shear zones are part of the major NE-SW lineaments that affect all southern Brazilian and Uruguayan Precambrian terrains. They separate the Dom Feliciano Schist Belt (supra crustal rocks of the Brusque-Porongos and Lavalleja groups), to the West, from the granitoids of the Granite belt, to the East. The shear zones are characterized by a regional NE trend and a resultant oblique direction of movement where ductile-brittle structures predominate

  10. Identification of thermotectonics events by 40Ar/39Ar methodology, in Jauru, Pontes e Lacerda and Rio Alegre Terrane - southwest portion of Amazon Craton

    International Nuclear Information System (INIS)

    Paulo, Valeria Guimaraes de

    2005-01-01

    The southwest portion of Amazon Craton, subject of these work, correspond to the southwest region of Mato Grosso State and is inserted on Rio Negro-Juruena, Rondoniana-San Ignacio and Sunsas-Aguapei geochronologic Provinces. This region is surrounded by three big terranes: Jauru, Pontes e Lacerda and Rio Alegre. The main aim of this study is to use the ages of termochronologic events obtained by 40 Ar/ 39 Ar methodology, including data of literature, to contribute with the study of the geotectonic evolution on this region. Twenty samples were analyzed and 40 Ar/ 39 Ar ages found for the Jauru Terrane vary of 1539 ± 3 Ma to 1338 ± 3 Ma, for the Pontes e Lacerda Terrane the interval obtained was of 946,1 ± 0,8 Ma to 890 ± 2 Ma and for Rio Alegre Terrane the ages are between 1407 ± 3 Ma to 1321 ± 2 Ma. U/Pb, Rb/Sr and Sm/Nd data from previous works, together with 40 Ar/ 39 Ar results allowed to obtain cooling average rates to each terrane. The Jauru Terrane units cooling age is equivalent to 1,52 Ga. The cooling average rates found to Alto Jauru Greenstone belt rocks is 2,4 deg C - 1,0 Ma and to Magmatic Arc Cachoeirinha is 10,8 deg C - 1,0 Ma. Stabilization age obtained for Pontes and Lacerda Terrane is about 900 Ma coherent with the cooling age of the Sunsas Aguapei Event (1,0 - 0,9 Ga) and cooling average rates calculate were the lower, equivalent to 1,0 deg C - 1,0 Ma. Cooling age found in Rio Alegre Terrane was 1,35 Ga, possibility correspond to collision age these terrane with Amazonian protoCraton and cooling average rates of 5,0 deg C - 1,0 Ma. Finally, younger age found of 900 Ma, coherent to the Sunsas - Aguapei Event, probably represent the last regional event that affected these rocks, characterizing the stabilization period of the southwest portion of Amazon Craton. (author)

  11. Rb-Sr dating of strain-induced mineral growth in two ductile shear zones in the western gneiss region of Nord-Troendelag, Central Norway

    International Nuclear Information System (INIS)

    Piasecki, M.A.; Cliff, R.A.

    1988-01-01

    In the Bjugn district of the northern part of the Western Gneiss Region, Nord-Troendelag, a basement gneiss-cover nappe boundary is marked by a thick zone of ductile shearing. In this zone a layer-parallel mylonitic fabric with related new mineral growth overprints and retrogresses a previous fabric associated with a granulite facies mineral assemblage. Related minor shear belts contain abundant new minerals and vein systems, including pegmatites, believed to represent strain-induced products formed at the time of the shearing movements. Central parts of two large muscovite books from such a pegmatite yielded Rb-Sr, Early to Middle Devonian ages of 389±6 Ma and 386±6 Ma, interpreted as indicating the approximate time of pegmatite formation and of the shearing. Small, matrix-size muscovite and biotite grains from the host mylonite gave ages of 378±6 Ma and 365±5 Ma, respectively, supposed to relate to post-shearing uplift and cooling

  12. A geologic guide to Wrangell-Saint Elias National Park and Preserve, Alaska; a tectonic collage of northbound terranes

    Science.gov (United States)

    Winkler, Gary R.; with contributions by MacKevett, E. M.; Plafker, George; Richter, D.H.; Rosenkrans, D.S.; Schmoll, H.R.

    2000-01-01

    Wrangell-Saint Elias National Park and Preserve, the largest unit in the U.S. National Park System, encompasses near 13.2 million acres of geological wonderments. This geologic guide presents history of exploration and Earth-science investigation; describes the complex geologic makeup; characterizes the vast college of accretion geologic terranes in this area of Alaska's continental margin; recapitulates the effects of earthquakes, volcanoes, and glaciers; characterizes the copper and gold resources of the parklands; and describes outstanding locales within the park and preserve area. A glossary of geologic terms and a categorized list of additional sources of information complete this report.

  13. Geochronological data for lithostratigraphic complexes of a crystalline basement from the South regions of Minas Gerais and adjacent areas of the Sao Paulo state

    International Nuclear Information System (INIS)

    Kawashita, K.; Artur, A.C.; Wernick, E.

    1988-01-01

    New geochronological data (Rb/Sr, Pb/Pb) for the Amparo and Pinhal Complexes, southern State of Minas Gerais and adjacent areas of the State of Sao Paulo are presented and discussed with respect to other lithostratigraphic complexes which there occur. Among the different complexes considered, 4 are composed mainly by rock belonging to typical infrastructure associations. They are the Barcelona, the Guaxupe, the Amparo and the Pinhal complexes. The Barbacena Complex is a typical gray gneiss complex and geochronological data by different methods confirm its Archean age. The Guaxupe Complex is composed mainly by different types of charnockitic rocks and an Archean age is assumed on geotectonic basis due to its neighboring association with the gray gneiss/greenstone belt, a though confirming geochronological data are still missing, a normal feature in this type of mobile belts which generally show a complex, polycyling evolution. Geochronological data by different methods on diverse rock types indicates that the Amparo and Pinhal complexes are respectively of Lower an Upper proterozoic age. Geochronological, geological and petrographic data reveal that both complexes are composed mainly by 3 basic rock associations: a-mainly derived magmatic rocks including mafic/ultramafic ones as well as calc-alkaline, subalcaline and even alkaline granitoids; b-orthogneisses, migmatites and crustal granites derived by metamorphic processes acting on older, pre-existing rocks; corthogneisses and migmatites resulting from metamorphic processes acting on magmatic rocks intruded during the same tecto-metamorphic cycle during which its transformation took place. The results suggest a polycyclic evolution by successive tecto-metamorphic events which affected the older rocks of the considered are either by the reworking of enclosing rocks around pericratonic continental main magmatic arcs or by the remobilisation of older basement rocks during continental collisions. (author) [pt

  14. Continuation, south of Oaxaca City (southern Mexico) of the Oaxaca-Juarez terrane boundary and of the Oaxaca Fault. Based in MT, gravity and magnetic studies

    Science.gov (United States)

    Campos-Enriquez, J. O.; Corbo, F.; Arzate-Flores, J.; Belmonte-Jimenez, S.; Arango-Galván, C.

    2010-12-01

    The Oaxaca Fault represents Tertiary extensional reactivation of the Juarez shear zone constituting the boundary-suture between the Oaxaca and Juarez terranes (southern Mexico). South of Oaxaca City, the fault trace disappears and there are not clear evidences for its southward continuation at depth. The crust in southern México has been studied through seismic refraction, and seismological and magnetotelluric (MT) studies. The refraction studies did not image the Oaxaca Fault. However, previous regional MT studies suggest that the Oaxaca-Juarez terrane boundary lies to the east of the Zaachila and Mitla sub-basins, which implies sinistral displacement along the Donaji Fault. Campos-Enriquez et al. (2009) established the shallow structure of the Oaxaca-Juarez terrane boundary based in detailed gravity and magnetic studies. This study enabled: 1) to establish the shallow structure of the composite depression comprising three N-S sub-basins: the northern Etla and southern Zaachila sub-basins separated by the Atzompa sub-basin. According to the Oaxaca-Juarez terrane boundary is displaced sinistrally ca. 20 km along the E-W Donají Fault, which defines the northern boundary of the Zaachila sub-basin. At the same time,, the Oaxaca Fault may either continue unbroken southwards along the western margin of a horst in the Zaachila sub-basin or be offset along with the terrane boundary. This model implies that originally the suture was continuous south of the Donaji Fault. A constraint for the accreation of the Oaxaca and Juarez terranes. Thirty MT soundings were done in the area of the Central Valleys, Oaxaca City (southern Mexico). In particular we wanted to image the possible southward continuation of the Oaxaca Fault. 22 Mt sounding are located along two NE-SW profiles to the northern and to the south of the City of Oaxaca. To the north of Oaxaca City, the electrical resistivity distribution obtained show a clear discontinuity across the superficial trace of the Oaxaca

  15. Geology of the Severnaya Zemlya Archipelago and the North Kara Terrane in the Russian high Arctic

    Science.gov (United States)

    Lorenz, Henning; Männik, Peep; Gee, David; Proskurnin, Vasilij

    2008-05-01

    The Severnaya Zemlya Archipelago is located at 80°N near the continental shelf break, between the Kara and Laptev seas. Sedimentary successions of Neoproterozoic and Palaeozoic age dominate the bedrock geology. Together with Northern Tajmyr, Severnaya Zemlya constitutes the main land areas of the North Kara Terrane (NKT), which is inferred here to have been a part of the Timanide margin of Baltica, i.e. an integral part of Baltica at least since the Vendian. Vendian turbidites derived from the Timanide Orogen are inferred to have been deposited on Neoproterozoic greenschist facies, granite-intruded basement. Shallow-water siliclastic deposition in the Early to Mid-Cambrian was followed by highly organic-rich shales in the Late Cambrian and influx of more turbidites. An episode of folding, the Kan’on River deformation, separates these formations from the overlying Tremadocian conglomerates and sandstones. In the Early Ordovician, rift-related magmatic rocks accompanied the deposition of variegated marls, sandstones, carbonates and evaporites. Dark shales and gypsiferous limestones characterise the Mid-Ordovician. Late Ordovician quartz-sandstones mark a hiatus, followed by carbonate rocks that extend up into and through most of the Silurian. The latter give way upwards into Old Red Sandstones, which are inferred to have been deposited in a Caledonian foreland basin. Deformation, reaching the area in the latest Devonian or earliest Carboniferous and referred to as the Severnaya Zemlya episode, is thought to be Caledonian-related. The dominating E-vergent structure was controlled by décollement zones in Ordovician evaporite-bearing strata; detachment folds and thrusts developed in the west and were apparently impeded by a barrier of Ordovician igneous rocks in the east. Below the décollement zones, the Neoproterozoic to Early Ordovician succession was deformed into open to close folds. The exposed strata in the lower structural level have been juxtaposed with

  16. Evaluating the controls on Tourmaline Crystallization in the mylonitic granite-gneiss pluton in the Northeastern of Jan mine (Lorestan province

    Directory of Open Access Journals (Sweden)

    Arezoo Moradi

    2017-02-01

    Full Text Available Introduction The study area is a part of the Sanandaj- Sirjan zone that is located in the NW of Azna city and NE of the dimension stone mine of Jan between 49° 11' 41"and 49° 16' 07" E longitude and 33° 36'35" and 33° 38'12" N latitude., A pluton of mylonitic granite-gneiss is exposed in the area which contains abundant tourmalines as black and patchy or subgrain association. Geochemically, the studied granite-gneiss is A-type, peraluminous to slightly metaluminous and calc – alkaline to slightly alkaline (Moradi et al., 7. The electron microprobe analyses of the tourmalines display shorl-dravite in composition with more tendency to shorl (Moradi et al., 2015. In this paper we try to study the petrological sites of tourmaline formation with associated minerals, controller factors of crystallization using mineral chemistry of tourmaline, comprehensive behavior of trace elements in the tourmaline, synthetic phase diagrams and finally relationships between the associated minerals. Materials and methods The results of trace-element and major-element analyses were obtained from one polished thin section including 2 tourmaline grains. Major-element analyses of tourmaline were obtained at Oklahama City University of America using the JEOL 8200 electron microprobe with a spot size of 5 μm and trace-element analyses were performed on just a sample by Laser Ablation-Inductively Coupled Plasma-Mass Spectroscopy (LA-ICP-MS a 193nm ArF excimer laser ablation system (MicroLas GeoLas 200Q in combination with a quadrupole ICP-MS (Micromass Platform ICP at Utrecht University of Netherland. Representative EMP and LA-ICP-MS analyses of tourmaline samples are presented in Tables1 and 2. Results The results of LA-ICP-MS on tourmalines of Jan mine in the North east of mylonitic granite-gneiss body show that distribution and diffusion of trace elements during the growth of tourmaline trend is positive on the plots of binary Mn versus Fetot / (Fetot +Mg and it

  17. Neuromuscular adaptations induced by adjacent joint training.

    Science.gov (United States)

    Ema, R; Saito, I; Akagi, R

    2018-03-01

    Effects of resistance training are well known to be specific to tasks that are involved during training. However, it remains unclear whether neuromuscular adaptations are induced after adjacent joint training. This study examined the effects of hip flexion training on maximal and explosive knee extension strength and neuromuscular performance of the rectus femoris (RF, hip flexor, and knee extensor) compared with the effects of knee extension training. Thirty-seven untrained young men were randomly assigned to hip flexion training, knee extension training, or a control group. Participants in the training groups completed 4 weeks of isometric hip flexion or knee extension training. Standardized differences in the mean change between the training groups and control group were interpreted as an effect size, and the substantial effect was assumed to be ≥0.20 of the between-participant standard deviation at baseline. Both types of training resulted in substantial increases in maximal (hip flexion training group: 6.2% ± 10.1%, effect size = 0.25; knee extension training group: 20.8% ± 9.9%, effect size = 1.11) and explosive isometric knee extension torques and muscle thickness of the RF in the proximal and distal regions. Improvements in strength were accompanied by substantial enhancements in voluntary activation, which was determined using the twitch interpolation technique and RF activation. Differences in training effects on explosive torques and neural variables between the two training groups were trivial. Our findings indicate that hip flexion training results in substantial neuromuscular adaptations during knee extensions similar to those induced by knee extension training. © 2017 The Authors. Scandinavian Journal of Medicine & Science In Sports Published by John Wiley & Sons Ltd.

  18. Constraints of detrital zircon U-Pb ages and Hf isotopes on the provenance of the Triassic Yidun Group and tectonic evolution of the Yidun Terrane, Eastern Tibet

    Science.gov (United States)

    Wang, Bai-Qiu; Wang, Wei; Chen, Wei Terry; Gao, Jian-Feng; Zhao, Xin-Fu; Yan, Dan-Ping; Zhou, Mei-Fu

    2013-05-01

    Eastern Tibet to the west of the Yangtze Block consists of the Yidun and Songpan-Ganzi Terranes, separated by the Ganzi-Litang suture zone. The Yidun Terrane includes the Zhongza Massif to the west, but the eastern part of the Yidun terrane is covered by the Yidun Group extending from the south (Shangri-La region) to the north (Changtai region). The Yidun Group, from the base upward, includes the Lieyi, Qugasi, Tumugou and Lanashan formations, which are mainly composed of volcanic-flysch successions. Based on the ages of volcanic interlayers and plutonic intrusions, depositional ages of the Qugasi and Tumugou formations are considered to be slightly older than 230 Ma and ca. 220-230 Ma respectively, which are prominently older than the previous estimates. The Yidun Group in the Changtai region has two prominent detrital zircon age peaks at 400-480 and 880-980 Ma and a minor peak at 2.45-2.50 Ga. This pattern suggests a detritus source from the Zhongza Massif, which was a micro-continent separated from the western Yangtze Block. In contrast, the Yidun Group in the Shangri-La region has various zircon age spectra among different formations. The Qugasi Formation in this region has detrital zircon age patterns similar to the Yidun Group in the Changtai region. However, the overlying Tumugou Formation shows distinct age peaks at Triassic (220-240 Ma), Neoproterozoic (~ 720-880 Ma), and Paleoproterozoic (~ 1.75-1.90 Ga). This age pattern is similar to that of the Xikang Group of the Songpan-Ganzi Terrane to the east. The detrital zircon age difference between the Qugasi and Tumugou formations in this region indicates a transition of sedimentary sources from the Zhongza Massif to locally distributed Triassic magmatic rocks at ~ 230 Ma. It is thus suggested that the Songpan-Ganzi Terrane may have been connected to or collided with the southern part of the Yidun Terrane during the Late Triassic, whereas the Songpan-Ganzi Terrane and the northern part of the Yidun Terrane

  19. The Ellsworth terrane, coastal Maine: Geochronology, geochemistry, and Nd-Pb isotopic composition - Implications for the rifting of Ganderia

    Science.gov (United States)

    Schulz, K.J.; Stewart, D.B.; Tucker, R.D.; Pollock, J.C.; Ayuso, R.A.

    2008-01-01

    The Ellsworth terrane is one of a number of fault-bounded blocks that occur along the eastern margin of Ganderia, the western-most of the peri-Gondwanan domains in the northern Appalachians that were accreted to Laurentia in the Paleozoic. Geologic relations, detrital zircon ages, and basalt geochemistry suggest that the Ellsworth terrane is part of Ganderia and not an exotic terrane. In the Penobscot Bay area of coastal Maine, the Ellsworth terrane is dominantly composed of bimodal basalt-rhyolite volcanic sequences of the Ellsworth Schist and unconformably overlying Castine Volcanics. We use new U-Pb zircon geochronology, geochemistry, and Nd and Pb isotopes for these volcanic sequences to constrain the petrogenetic history and paleotectonic setting of the Ellsworth terrane and its relationship with Ganderia. U-Pb zircon geochronology for rhyolites indicates that both the Ellsworth Schist (508.6 ?? 0.8 Ma) and overlying Castine Volcanics (503.5 ?? 2.5 Ma) are Middle Cambrian in age. Two tholefitic basalt types are recognized. Type Tb-1 basalt, present as pillowed and massive lava flows and as sills in both units, has depleted La and Ce ([La/Nd]N = 0.53-0.87) values, flat heavy rare earth element (REE) values, and no positive Th or negative Ta anomalies on primitive mantle-normalized diagrams. In contrast, type Th-2 basalt, present only in the Castine Volcanics, has stightly enriched LREE ([La/Yb]N = 1.42-2.92) values and no Th or Th anomalies. Both basalt types have strongly positive ??Nd (500) values (Th-1 = +7.9-+8.6; Th-2 = +5.6-+7.0) and relatively enriched Pb isotopic compositions (206Ph/204Pb = 18.037-19.784; 207/204Pb = 15.531-15.660; 2088Pb/204Pb = 37.810-38.817). The basalts have compositions transitional between recent normal and enriched mid-ocean-ridge basalt, and they were probably derived by partial melting of compositionatly heterogeneous asthenosphenc mantle. Two types of rhyolite also are present. Type R-1 rhyolite, which mostly occurs as tuffs

  20. The UHP metamorphic Seve Nappe Complex of the Swedish Caledonides - a new occurrence of the microdiamond-bearing gneisses and their exhumation

    Science.gov (United States)

    Klonowska, Iwona; Janák, Marian; Majka, Jarosław; ‎ Froitzheim, Nikolaus; Gee, David G.

    2015-04-01

    The ultra-high pressure metamorphism (UHPM) in the Seve Nappe Complex of the Swedish Caledonides has been recently recognized within several lithologies including gneisses, eclogites and garnet pyroxenites (e.g. Janák et al. 2013, Klonowska et al. 2014a, Majka et al. 2014). Thermodynamic modelling and thermobarometric calculations indicate peak pressure conditions of >3GPa at c. 800-900°C (reaching the diamond stability field) for eclogites and garnet pyroxenites from northern Jämtland (e.g. Klonowska et al. 2014b). In addition to this, the first microdiamonds were found in paragneisses from the Snasahögarna Mt. in central Jämtland (Majka et al. 2014). Here we report a new discovery of microdiamond together with moissanite (SiC) from one of the world's most famous localities for thrusting, Mount Åreskutan, where long transport distances were recognized already in the 19th century (Törnebohm 1888). Garnet porphyroblasts in gneisses from the Åreskutan Mt. contain abundant mineral inclusions, mainly graphite, carbonates and quartz, together with fluid inclusions of CO2 concentrated in swarms. Among these inclusions three microdiamonds were found in two gneiss samples. In one of the samples moissanite was also discovered. Both minerals were identified by micro-Raman spectroscopy. In addition to these 'swarm' inclusions, biotite, kyanite, rutile, feldspars, zircon, monazite, ±phengite, ±muscovite, ±spinel, ±ilmenite, ±apatite occur in garnets. Phase equilibrium modelling for the phengite-bearing gneiss confirms its UHP history at temperatures of c. 800°C. Recent discoveries of UHP metamorphism within the Seve Nappe Complex derived from the Baltican outer margin (part of the Middle Allochthon) challenged us to present a new tectonic model incorporating exhumation of the deeply subducted continental rocks together with mantle lithosphere peridotites. Majka et al. (2014) introduced a new "under-pressure"-driven exhumation mechanism of rocks buried in

  1. 33 CFR 80.1395 - Puget Sound and adjacent waters.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Puget Sound and adjacent waters. 80.1395 Section 80.1395 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... waters. The 72 COLREGS shall apply on all waters of Puget Sound and adjacent waters, including Lake Union...

  2. Early Verb Constructions in French: Adjacency on the Left Edge

    Science.gov (United States)

    Veneziano, Edy; Clark, Eve V.

    2016-01-01

    Children acquiring French elaborate their early verb constructions by adding adjacent morphemes incrementally at the left edge of core verbs. This hypothesis was tested with 2657 verb uses from four children between 1;3 and 2;7. Consistent with the Adjacency Hypothesis, children added clitic subjects frst only to present tense forms (as in…

  3. Objectifying the Adjacent and Opposite Angles: A Cultural Historical Analysis

    Science.gov (United States)

    Daher, Wajeeh; Musallam, Nadera

    2018-01-01

    The angle topic is central to the development of geometric knowledge. Two of the basic concepts associated with this topic are the adjacent and opposite angles. It is the goal of the present study to analyze, based on the cultural historical semiotics framework, how high-achieving seventh grade students objectify the adjacent and opposite angles'…

  4. On Pathos Adjacency Cut Vertex Jump Graph of a Tree

    OpenAIRE

    Nagesh.H.M; R.Chandrasekhar

    2014-01-01

    In this paper the concept of pathos adjacency cut vertex jump graph PJC(T) of a tree T is introduced. We also present a characterization of graphs whose pathos adjacency cut vertex jump graphs are planar, outerplanar, minimally non-outerplanar, Eulerian and Hamiltonian.

  5. GPR Imaging of Fault Related Folds in a Gold-Bearing Metasedimentary Sequence, Carolina Terrane, Southern Appalachian Mountains

    Science.gov (United States)

    Diemer, J. A.; Bobyarchick, A. R.

    2015-12-01

    The Carolina terrane comprises Ediacaran to earliest Paleozoic mixed magmatic and sedimentary assemblages in the central and eastern Piedmont of the Southern Appalachian Mountains. The terrane was primarily deformed during the Late Ordovician Cherokee orogeny, that reached greenschist facies metamorphism. The Albemarle arc, a younger component of the Carolina terrane, contains volcanogenic metasedimentary rocks with intercalated mainly rhyolitic volcanic rocks. Regional inclined to overturned folds with axial planar cleavage verge southeast. At mesoscopic scales (exposures of a few square meters), folds sympathetic with regional folds are attenuated or truncated by ductile shear zones or contractional faults. Shear and fault zones are most abundant near highly silicified strataform zones in metagraywacke of the Tillery Formation; these zones are also auriferous. GPR profiles were collected across strike of two silicified, gold-bearing zones and enclosing metagraywacke to characterize the scale and extent of folding in the vicinity of ore horizons. Several GSSI SIR-3000 / 100 MHz monostatic GPR profiles were collected in profiles up to 260 meters long. In pre-migration lines processed for time zero and background removal, several clusters of shallow, rolling sigmoidal reflectors appeared separated by sets of parallel, northwest-dipping reflective discontinuities. These features are inferred to be reverse faults carrying contractional folds. After migration with an average velocity of 0.105 m/ns, vertical heights of the inferred folds became attenuated but not removed, and contractional fault reflections remained prominent. After migration, a highly convex-up cluster of reflections initially assumed to be a fold culmination resolved to an elliptical patch of high amplitudes. The patch is likely an undisclosed shaft or covered trench left by earlier gold prospecting. In this survey, useful detail appeared to a depth of 7.5 meters, and only a few gently inclined

  6. Cenozoic mantle composition evolution of southern Tibet indicated by Paleocene ( 64 Ma) pseudoleucite phonolitic rocks in central Lhasa terrane

    Science.gov (United States)

    Qi, Yue; Gou, Guo-Ning; Wang, Qiang; Wyman, Derek A.; Jiang, Zi-Qi; Li, Qiu-Li; Zhang, Le

    2018-03-01

    The question of whether continental subduction processes in collisional orogenic belts can trigger wide-spread mantle metesomatism and crustal material recycling remains unresolved. Miocene (25-8 Ma) ultrapotassic rocks in southern Tibet are the only mantle-derived magmatic rocks emplaced after the collision between India and Asia and they have been linked to the onset of east-west extensional stresses as the surface uplift of the Tibetan Plateau reached near-maximum elevation. However, their petrogenesis remains highly controversial, particularly the issue of whether their extremely enriched Sr-Nd isotopic characteristics were related to metasomatism derived from subducted Indian continental materials during the Cenozoic. Here we report on a Paleocene silicate-unsaturated, pseudoleucite phonolitic dike, in the Rongniduo area of central Lhasa terrane. In-situ SIMS (secondary ion mass spectrometry) apatite U-Pb age indicates the dike was generated at 64.1 ± 4.2 Ma, which slightly predates the age of initial India and Asia collision (about 55-50 Ma). This is the oldest age yet reported for ultrapotassic rocks in southern Tibet. Samples from this dike have distinctly more depleted Sr-Nd (whole rock: (87Sr/86Sr)i = 0.7064 to 0.7062, εNd(t) = - 1.5 to 0.4; in situ apitite: (87Sr/86Sr)i = 0.7059 to 0.7060, εNd(t) = - 2.0 to 0.4) isotopic compositions, than those of Miocene (25-8 Ma) ultrapotassic rocks in the central Lhasa terrane ((87Sr/86Sr)i = 0.7106 to 0.7399, εNd(t) = - 10.6 to - 18.5). Our new data provides important constraints on pre-collisional mantle characteristics beneath the Lhasa terrane. We suggest that these 64 Ma pseudoleucite phonolitic rocks were derived from the enriched lithospheric mantle metasomatized by subducted Tethyan oceanic materials in response to Neo-Tethyan slab roll-back. As a consequence, the younger Miocene ultrapotassic rocks, which display different geochemical compositions from the pre-collisional ultrapotassic rocks, were most

  7. Geochronological and geochemical constraints on the origin of the Yunzhug ophiolite in the Shiquanhe-Yunzhug-Namu Tso ophiolite belt, Lhasa Terrane, Tibetan Plateau

    Science.gov (United States)

    Zeng, Yun-Chuan; Xu, Ji-Feng; Chen, Jian-Lin; Wang, Bao-Di; Kang, Zhi-Qiang; Huang, Feng

    2018-02-01

    The formation of the Shiquanhe-Yunzhug-Namu Tso ophiolite mélange zone (SNMZ) within the Lhasa Terrane, Tibetan Plateau, is key to understanding the Mesozoic tectonic evolution of this terrane, which remains controversial. We show that the Yunzhug ophiolite in the central segment of the SNMZ formed at 150 Ma, based on U-Pb dating of zircons from a gabbroic sample in a well-developed sheeted dike complex. Geochemically, these mafic rocks are dominated by E-MORB-type compositions, along with minor amounts of rocks with P-MORB-type compositions. The samples also exhibit high εNd(t) values and lack negative Nb and Ta anomalies. Data for all the samples plot within the MORB array on a Th/Yb-Nb/Yb diagram. Therefore, these mafic rocks most likely formed in either a slow spreading oceanic setting or an embryonic ocean, and not in a back-arc basin as has been previously assumed. Taking into account the regional geology, we propose that the Yunzhug ophiolite is part of a distinct ophiolitic belt and represents material formed in an embryonic ocean within the Lhasa Terrane, which provides new insights into the Jurassic tectonic evolution of the Lhasa Terrane.

  8. Grenville age of basement rocks in Cape May NJ well: New evidence for Laurentian crust in U.S. Atlantic Coastal Plain basement Chesapeake terrane

    Science.gov (United States)

    Sheridan, R.E.; Maguire, T.J.; Feigenson, M.D.; Patino, L.C.; Volkert, R.A.

    1999-01-01

    The Chesapeake terrane of the U.S. mid-Atlantic Coastal Plain basement is bounded on the northwest by the Salisbury positive gravity and magnetic anomaly and extends to the southeast as far as the Atlantic coast. It underlies the Coastal Plain of Virginia, Maryland, Delaware and southern New Jersey. Rubidium/Strontium dating of the Chesapeake terrane basement yields an age of 1.025 ?? 0.036 Ga. This age is typical of Grenville province rocks of the Middle to Late Proterozoic Laurentian continent. The basement lithologies are similar to some exposed Grenville-age rocks of the Appalachians. The TiO2 and Zr/P2O5 composition of the metagabbro from the Chesapeake terrane basement is overlapped by those of the Proterozoic mafic dikes in the New Jersey Highlands. These new findings support the interpretation that Laurentian basement extends southeast as far as the continental shelf in the U.S. mid-Atlantic region. The subcrop of Laurentian crust under the mid-Atlantic Coastal Plain implies unroofing by erosion of the younger Carolina (Avalon) supracrustal terrane. Dextral-transpression fault duplexes may have caused excessive uplift in the Salisbury Embayment area during the Alleghanian orogeny. This extra uplift in the Salisbury area may have caused the subsequent greater subsidence of the Coastal Plain basement in the embayment.

  9. Lost Terranes of Zealandia: possible development of late Paleozoic and early Mesozoic sedimentary basins at the southwest Pacific margin of Gondwanaland, and their destination as terranes in southern South America Terrenos perdidos de Zealandia: posible desarrollo de cuencas sedimentarias del Paleozoico tardío y Mesozoico temprano en el margen suroccidental del Pacífico de Gondwana y su destino como terrenos en el sur de América del Sur

    Directory of Open Access Journals (Sweden)

    Christopher J Adams

    2010-07-01

    Full Text Available Latest Precambrian to Ordovician metasedimentary successions and Cambrian-Ordovician and Devonian-Carboniferous granitoids form the major part of the basement of southern Zealandia and adjacent sectors of Antarctica and southeast Australia. Uplift/cooling ages of these rocks, and local Devonian shallow-water cover sequences suggest that final consolidation of the basement occurred through Late Paleozoic time. A necessary consequence of this process would have been contemporaneous erosion and the substantial development of marine sedimentary basins at the Pacific margin of Zealandia. These are found nowhere at the present day, suggesting that the basins have been lost by tectonic erosion, perhaps in a margin-parallel dextral translation similar to late Paleozoic-Mesozoic suspect terranes of New Zealand. Aprobable detrital zircon age pattern is assembled for these lost Zealandia sediments, and then compared with those of pre-Jurassic (probable Triassic to Devonian metasedimentary rocks in the Chilean archipelago. Significant Mesoproterozoic, latest Neoproterozoic-Cambrian and Devonian-Carboniferous detrital zircon age components are common to both, thus supporting a possible Chilean terrane destination for these 'lost terranes of Zealandia'.Las sucesiones metasedimentarias del Precámbrico tardío al Ordovícico y granitoides del Cámbrico-Ordovícico y Devónico-Carbonífero constituyen la mayor parte del basamento del sur de Zealandia y sectores adyacentes de la Antartica y el sudeste de Australia. Las edades de enfriamiento/alzamiento de estas rocas y la cobertura local de secuencias de aguas someras del Devónico, sugieren que la consolidación definitiva del basamento se produjo durante el Paleozoico tardío. Una consecuencia necesaria de este proceso habría sido la erosion contemporánea y el desarrollo sustancial de cuencas sedimentarias marinas en el margen del Pacífico de Zealandia. Estas no se encuentran en ninguna parte en la

  10. Loading effects of anterior cervical spine fusion on adjacent segments

    Directory of Open Access Journals (Sweden)

    Chien-Shiung Wang

    2012-11-01

    Full Text Available Adjacent segment degeneration typically follows anterior cervical spine fusion. However, the primary cause of adjacent segment degeneration remains unknown. Therefore, in order to identify the loading effects that cause adjacent segment degeneration, this study examined the loading effects to superior segments adjacent to fused bone following anterior cervical spine fusion. The C3–C6 cervical spine segments of 12 sheep were examined. Specimens were divided into the following groups: intact spine (group 1; and C5–C6 segments that were fused via cage-instrumented plate fixation (group 2. Specimens were cycled between 20° flexion and 15° extension with a displacement control of 1°/second. The tested parameters included the range of motion (ROM of each segment, torque and strain on both the body and inferior articular process at the superior segments (C3–C4 adjacent to the fused bone, and the position of the neutral axis of stress at under 20° flexion and 15° extension. Under flexion and Group 2, torque, ROM, and strain on both the bodies and facets of superior segments adjacent to the fused bone were higher than those of Group 1. Under extension and Group 2, ROM for the fused segment was less than that of Group 1; torque, ROM, and stress on both the bodies and facets of superior segments adjacent to the fused bone were higher than those of Group 1. These analytical results indicate that the muscles and ligaments require greater force to achieve cervical motion than the intact spine following anterior cervical spine fusion. In addition, ROM and stress on the bodies and facets of the joint segments adjacent to the fused bone were significantly increased. Under flexion, the neutral axis of the stress on the adjacent segment moved backward, and the stress on the bodies of the segments adjacent to the fused bone increased. These comparative results indicate that increased stress on the adjacent segments is caused by stress-shielding effects

  11. Geochronology and geochemistry of the Early Jurassic Yeba Formation volcanic rocks in southern Tibet: Initiation of back-arc rifting and crustal accretion in the southern Lhasa Terrane

    Science.gov (United States)

    Wei, Youqing; Zhao, Zhidan; Niu, Yaoling; Zhu, Di-Cheng; Liu, Dong; Wang, Qing; Hou, Zengqian; Mo, Xuanxue; Wei, Jiuchuan

    2017-05-01

    Understanding the geological history of the Lhasa Terrane prior to the India-Asia collision ( 55 ± 10 Ma) is essential for improved models of syn-collisional and post-collisional processes in the southern Lhasa Terrane. The Miocene ( 18-10 Ma) adakitic magmatism with economically significant porphyry-type mineralization has been interpreted as resulting from partial melting of the Jurassic juvenile crust, but how this juvenile crust was accreted remains poorly known. For this reason, we carried out a detailed study on the volcanic rocks of the Yeba Formation (YF) with the results offering insights into the ways in which the juvenile crust may be accreted in the southern Lhasa Terrane in the Jurassic. The YF volcanic rocks are compositionally bimodal, comprising basalt/basaltic andesite and dacite/rhyolite dated at 183-174 Ma. All these rocks have an arc-like signature with enriched large ion lithophile elements (LILEs; e.g., Rb, Ba and U) and light rare earth elements (LREEs) and depleted high field strength elements (HFSEs; e.g., Nb, Ta, Ti). They also have depleted whole-rock Sr-Nd and zircon Hf isotopic compositions, pointing to significant mantle isotopic contributions. Modeling results of trace elements and isotopes are most consistent with the basalts being derived from a mantle source metasomatized by varying enrichment of subduction components. The silicic volcanic rocks show the characteristics of transitional I-S type granites, and are best interpreted as resulting from re-melting of a mixed source of juvenile amphibole-rich lower crust with reworked crustal materials resembling metagraywackes. Importantly, our results indicate northward Neo-Tethyan seafloor subduction beneath the Lhasa Terrane with the YF volcanism being caused by the initiation of back-arc rifting. The back-arc setting is a likely site for juvenile crustal accretion in the southern Lhasa Terrane.

  12. Precambrian Field Camp at the University of Minnesota Duluth - Teaching Skills Applicable to Mapping Glaciated Terranes of the Canadian Shield

    Science.gov (United States)

    Miller, J. D.; Hudak, G. J.; Peterson, D.

    2011-12-01

    Since 2007, the central program of the Precambrian Research Center (PRC) at the University of Minnesota Duluth has been a six-week geology field camp focused on the Precambrian geology of the Canadian Shield. This field camp has two main purposes. First and foremost is to teach students specialized field skills and field mapping techniques that can be utilized to map and interpret Precambrian shield terranes characterized by sparse outcrop and abundant glacial cover. In addition to teaching basic outcrop mapping technique , students are introduced to geophysical surveying (gravity, magnetics), glacial drift prospecting, and drill core logging techniques in several of our geological mapping exercises. These mapping methodologies are particularly applicable to minerals exploration in shield terranes. The second and equally important goal of the PRC field camp is to teach students modern map-making and map production skills. During the fifth and sixth weeks of field camp, students conduct "capstone" mapping projects. These projects encompass one week of detailed bedrock mapping in remote regions of northern Minnesota that have not been mapped in detail (e.g. scales greater than 1:24,000) and a second week of map-making and map generation utilizing geographic information systems (currently ArcGIS10), graphics software packages (Adobe Illustrator CS4), and various imaging software for geophysical and topographic data. Over the past five years, PRC students and faculty have collaboratively published 21 geologic maps through the Precambrian Research Center Map Series. These maps are currently being utilized in a variety of ways by industry, academia, and government for mineral exploration programs, development of undergraduate, graduate, and faculty research projects, and for planning, archeological studies, and public education programs in Minnesota's state parks. Acquisition of specialized Precambrian geological mapping skills and geologic map-making proficiencies has

  13. Gneisses (Serizzi and Beole) of the Verbano-Cusio-Ossola district (Piedmont, Northern Italy): possible candidates for the designation of "Global Heritage Stone province"

    Science.gov (United States)

    Antonella Dino, Giovanna; Borghi, Alessandro; Cavallo, Alessandro; Primavori, Piero

    2016-04-01

    The Verbano-Cusio-Ossola quarrying district (Piedmont, northern Italy) produces many different ornamental stones (granites, gneisses, marbles): two really important categories are represented by Serizzo and Beola gneisses. Several varieties of Serizzo and Beola crop out in the upper and middle Ossola Valley: Serizzo derives from the Antigorio, Monte Leone and Monte Rosa Penninic Units, whereas Beola from the Monte Leone, Orselina-Moncucco-Isorno and Monte Rosa Penninic Units, as well from the Fobello-Rimella schists (Austroalpine). The Serizzo, represented by a group of foliated granitoid orthogneisses (Serizzo Antigorio, Serizzo Formazza, Serizzo Sempione and Serizzo Monte Rosa varieties), is probably the most important and extensively exploited ornamental stones from the VCO province (about 70% of the VCO stone production). The quarries are mostly concentrated in the Antigorio and Formazza valleys, where the Antigorio nappe has a sub-horizontal attitude and reaches its greatest thickness (up to 1000 m). This stone was largely used to produce columns since the end of XV century (e.g. the old Ospedale Maggiore in Milano, now University of Milano) and later on it was replaced with granites. It was also used in the building structure of the Duomo di Milano, for the plinth and the piers. Nowadays, thanks to its good wear resistance and low cost, it is mainly used in polished slabs for paving: a recent application is the Frankfurt airport floor. Beola is the name of a group of heterogeneous orthogneisses with mylonitic foliation and strong mineralogical lineation (Beola Grigia, Bianca, Ghiandonata, Striata varieties), easy to split into thin slabs with hammer and chisel, occurring in the middle Ossola Valley, between Vogogna and Montecrestese. The quarries of Beola are probably the oldest of the Ossola Valley, although the precise period in which the stone started to be exported is unknown. The Beola trade probably started at the end of the XIII century, with the

  14. U-Pb ages for two tonalitic gneisses, pegmatitic granites, and K-feldspar porphyries, Olkiluoto study site, Eurajoki, SW Finland

    International Nuclear Information System (INIS)

    Maenttaeri, I.; Lindberg, A.; Aaltonen, I.

    2007-08-01

    Secondary ion microprobe zircon U-Pb ages have been determined for two tonalitic gneisses, two pegmatitic granites, and two potassium feldspar porphyry samples from the Olkiluoto study site, Eurajoki, S-W Finland. Moreover, monazites from the Kfeldspar porphyries were dated using TIMS U-Pb method. The tonalitic gneiss A1879 TTG 1 reveals bimodal zircon population and for A1880 TTG it is homogeneous. The samples yield similar overlapping concordia ages of 1851 ± 5 Ma and 1856 ± 5 Ma, respectively. The pegmatitic granite samples A1881 PGR 1 and A1883 PGR 2 have mostly zircons resembling those of the TTG's. The supposed pegmatitic zircons with high U and low Th are strongly altered. The zircon U-Pb data of A1881 PGR 1 plot roughly in two separate lines on a concordia diagram. The apparently younger ∼1.79 Ga data are all from the high U and low Th/U zircons and therefore certainly set the minimum age for the A1881 PGR 1. It is suggested, that the ∼1.85 Ga data comprise analyses from inherited zircons as it include both lower and higher Th/U zircons and 1.85 Ga coevals with age of the tonalitic gneisses. Thus, the apparent age for the A1881 PGR 1 is ∼1.79 Ga. The U-Pb data of sample A1883 PGR 2 also divide into two groups. The higher Th/U, inherited zircons determine an age of 1852 ± 9 Ma which is the same as that of the TTG's. The low Th/U zircon data scatter and the age of 1.83 Ga for A1883 PGR 2 is only poorly determined. The both potassium feldspar porphyry samples A1882 KFP 1 and A1884 KFP 2 reveal heterogeneous zircon populations. The A1882 KFP 1 zircons showing magmatic zoning in BSE images conceivably determine a concordia age of 1842± 6 Ma for the rock. In addition to that a few ∼1.9 Ga inherited zircon and metamorphic low Th/U rims with ages between 1.88 Ga and 1.83 Ga were detected. The age for the youngest metamorphic zircon rims overlaps with that of the magmatic zircons. The zircons in the other KFP sample A1884 show a wide range of ages

  15. Community conservation adjacent to Ruaha National Park, Tanzania

    Science.gov (United States)

    Sue Stolberger

    2007-01-01

    In the areas adjacent to Ruaha National Park where rural communities exist, much more work and education is required to enable them to benefit directly and indirectly from tourism and managing their own natural resources.

  16. Influence of cantilevered sheet pile deflection on adjacent roadways.

    Science.gov (United States)

    2009-06-01

    Cantilevered sheet pile walls are often used adjacent roadways as temporary support during construction. Excess movement of these walls has led to excessive roadway distress causing additional repairs to be necessary. This study assessed the effects ...

  17. Suprabasalt stratigraphy within and adjacent to the reference repository location

    International Nuclear Information System (INIS)

    Bjornstad, B.N.

    1983-01-01

    This data-package contains six detailed stratigraphic correlations and structure cross sections of suprabasalt sediments in the area adjacent to and including the Reference Repository Location. 4 refs., 1 fig

  18. Sleeping sickness surveys: game reserve adjacent villages in Malawi

    African Journals Online (AJOL)

    Sleeping sickness surveys: game reserve adjacent villages in Malawi. ... Sera from 160 game ranger volunteers and from 82 suspected cases_of Rhodesian sleeping sickness were tested by use of ELISA, ... AJOL African Journals Online.

  19. Objectifying the adjacent and opposite angles: a cultural historical analysis

    Science.gov (United States)

    Daher, Wajeeh; Musallam, Nadera

    2018-02-01

    The angle topic is central to the development of geometric knowledge. Two of the basic concepts associated with this topic are the adjacent and opposite angles. It is the goal of the present study to analyze, based on the cultural historical semiotics framework, how high-achieving seventh grade students objectify the adjacent and opposite angles' concepts. We videoed the learning of a group of three high-achieving students who used technology, specifically GeoGebra, to explore geometric relations related to the adjacent and opposite angles' concepts. To analyze students' objectification of these concepts, we used the categories of objectification of knowledge (attention and awareness) and the categories of generalization (factual, contextual and symbolic), developed by Radford. The research results indicate that teacher's and students' verbal and visual signs, together with the software dynamic tools, mediated the students' objectification of the adjacent and opposite angles' concepts. Specifically, eye and gestures perceiving were part of the semiosis cycles in which the participating students were engaged and which related to the mathematical signs that signified the adjacent and the opposite angles. Moreover, the teacher's suggestions/requests/questions included/suggested semiotic signs/tools, including verbal signs that helped the students pay attention, be aware of and objectify the adjacent and opposite angles' concepts.

  20. The Volpe Center GPS Adjacent Band Compatibility Program Plan : GPS Adjacent Band Compatibility Workshop, Volpe Center, Cambridge MA

    Science.gov (United States)

    2014-09-18

    Approach to DOT GPS Adjacent Band Compatibility Assessment. Identify forums and provide public outreach to make sure the progress and work are as open and transparent as possible. Develop an implementation plan that incorporates aspects from the DOT ...

  1. A practical assessment of aquifer discharge for regional groundwater demand by characterizing leaky confined aquifer overlain on a Mesozoic granitic gneiss basement

    Science.gov (United States)

    Shih, David Ching-Fang

    2018-04-01

    Due to increasing population worldwide, there is an urgent need to manage these important but diminishing groundwater resources efficiently to ensure their continued availability. The major innovative design of this study is to provide a practical assessment process for groundwater discharge under a regional demand by characterizing the nature of leaky confined aquifers overlain on a Mesozoic granitic gneiss basement which involves the important groundwater system in the Kinmen region (Taiwan, ROC) and the assessment of adoptable groundwater discharge in aquifer is needed. The storage coefficient presents an order of one in a thousand and hydraulic conductivity is approximately at the order of 1-8 m/d and 0.4-0.9 m/d for aquifer and aquitard respectively. Groundwater discharge and admissible number of pumping well is suggested considering scheduled maximum groundwater volume and head decline change for eastern and western studied area respectively. The safety subjected to the conservative issue is then addressed by the use of scheduled maximum groundwater volume. It reveals that the safety can be ensured using the indicator as scheduled maximum groundwater volume with predefined scenarios. The result can be utilized practically for developing management strategy of groundwater resources due to the applicability and novel of method.

  2. Release of uranium through cataclastic deformation of Mansehra granite gneiss and its precipitation in the overlying intramontane basin in northern Pakistan

    International Nuclear Information System (INIS)

    Butt, K.A.

    1989-01-01

    The Mansehra pluton belongs to a discontinuous belt of two mica granites of the Lesser Himalayas. The Mansehra granite is generally foliated except in the area around Mansehra. Several phases of granitic activity have been reported from the Mansehra Complex. Shams and Rahman have demonstrated that the younger phases tend to be enriched in Na 2 O. Ashraf extensively studied minor bodies ranging from albitites through aplites to pegmatites and suggested a late stage albitization event. The northern edge of this sheet-like granitic mass has undergone extensive cataclastic deformation, resulting in the formation of shear zones, mylonites and cataclasites. A chemical comparison of crushed granite with granite outside the shear zone suggests little chemical reconstitution in terms of major elements during cataclastic deformation. A huge shear zone in albitized granite gneiss has yielded secondary uranium minerals at water seepages, suggesting a liberation of uranium. Hydrogeochemical surveys of the crushed granite and adjoining areas suggest that uranium from crushed granite was easily leachable in comparison with rocks outside the shear zone. The uranium thus liberated was trapped in a Pleistocene sequence of clays and unsorted fluviatile sand overlying the granite and country rock metamorphics. (author). 17 refs, 2 figs, 2 tabs

  3. Revisiting elastic anisotropy of biotite gneiss from the Outokumpu scientific drill hole based on new texture measurements and texture-based velocity calculations

    Science.gov (United States)

    Wenk, H.-R.; Vasin, R. N.; Kern, H.; Matthies, S.; Vogel, S. C.; Ivankina, T. I.

    2012-10-01

    A sample of biotite gneiss from the Outokumpu deep drilling project in Finland was investigated by Kern et al. (2008) for crystal preferred orientation and elastic anisotropy. Considerable differences between measured acoustic velocities and velocities calculated on the basis of texture patterns were observed. Measured P-wave anisotropy was 15.1% versus a Voigt average yielding 7.9%. Here we investigate the same sample with different methods and using different averaging techniques. Analyzing time-of-flight neutron diffraction data from Dubna-SKAT and LANSCE-HIPPO diffractometers with the Rietveld technique, much stronger preferred orientation for biotite is determined, compared to conventional pole-figure analysis reported previously. The comparison reveals important differences: HIPPO has much better counting statistics but pole figure coverage is poor. SKAT has better angular resolution. Using the new preferred orientation data and applying a self-consistent averaging method that takes grain shapes into account, close agreement of calculated and measured P-wave velocities is observed (12.6%). This is further improved by adding 0.1 vol.% flat micropores parallel to the biotite platelets in the simulation (14.9%).

  4. A transect through the base of the Bronson Hill Terrane in western New Hampshire

    Science.gov (United States)

    Walsh, Gregory J.; Valley, Peter M.; Sicard, Karri R.; Thompson, Thelma Barton; Thompson, Peter J.

    2012-01-01

    This trip will present the preliminary results of ongoing bedrock mapping in the North Hartland and Claremont North 7.5-minute quadrangles in western New Hampshire. The trip will travel from the Lebanon pluton to just north of the Sugar River pluton (Fig. 1) with the aim of examining the lower structural levels of the Bronson Hill anticlinorium (BHA), and the nature of the boundary with the rocks of the Connecticut Valley trough (CVT). Spear and others (2002, 2003, 2008) proposed that western New Hampshire was characterized by five major faults bounding five structural levels including, from lowest to highest, the “chicken yard line”, Western New Hampshire Boundary Thrust, Skitchewaug nappe, Fall Mountain nappe, and Chesham Pond nappe. Lyons and others (1996, 1997) showed the lowest level cored by the Cornish nappe and floored by the Monroe fault. Thompson and others (1968) explained the geometry of units by folding without major thrust faults, and described the second level as the Skitchewaug nappe. This trip will focus on the two lowest levels which we have revised to call the Monroe and Skitchewaug Mountain thrust sheets. Despite decades of geologic mapping in the northeastern United States at various scales, little 1:24,000-scale (or larger scale) modern bedrock mapping has been published for the state of New Hampshire. In fact, of the New England states, New Hampshire contains the fewest published, modern bedrock geologic maps. Conversely, adjacent Vermont has a relatively high percentage of modern bedrock maps due to focused efforts to create a new state-wide bedrock geologic map over the last few decades. The new Vermont map (Ratcliffe and others, 2011) has identified considerable gaps in our knowledge of the bedrock geology in adjacent New Hampshire where published maps are, in places, more than 50 years old and at scales ranging from 1:62,500 to 1:250,000. Fundamental questions remain concerning the geology across the Connecticut River, especially in

  5. Integration of potential and quasipotential geophysical fields and GPR data for delineation of buried karst terranes in complex environments

    Science.gov (United States)

    Eppelbaum, L. V.; Alperovich, L. S.; Zheludev, V.; Ezersky, M.; Al-Zoubi, A.; Levi, E.

    2012-04-01

    Karst is found on particularly soluble rocks, especially limestone, marble, and dolomite (carbonate rocks), but is also developed on gypsum and rock salt. Subsurface carbonate rocks involved in karst groundwater circulation considerably extend the active karst realm, to perhaps 14% of the world's land area (Price, 2009). The phenomenon of the solution weathering of limestone is the most widely known in the world. Active sinkholes growth appears under different industrial constructions, roads, railways, bridges, airports, buildings, etc. Regions with arid and semi-arid climate occupy about 30% of the Earth's land. Subsurface in arid regions is characterized by high variability of physical properties both on lateral and vertical that complicates geophysical survey analysis. Therefore for localization and monitoring of karst terranes effective and reliable geophysical methodologies should be applied. Such advanced methods were developed in microgravity (Eppelbaum et al., 2008; Eppelbaum, 2011b), magnetic (Khesin et al., 1996; Eppelbaum et al., 2000, 2004; Eppelbaum, 2011a), induced polarization (Khesin et al., 1997; Eppelbaum and Khesin, 2002), VLF (Eppelbaum and Khesin, 1992; Eppelbaum and Mishne, 2012), near-surface temperature (Eppelbaum, 2009), self-potential (Khesin et al., 1996; Eppelbaum and Khesin, 2002), and resistivity (Eppelbaum, 1999, 2007a) surveys. Application of some of these methodologies in the western and eastern shores of the Dead Sea area (e.g., Eppelbaum et al., 2008; Ezersky et al., 2010; Al-Zoubi et al., 2011) and in other regions of the world (Eppelbaum, 2007a) has shown their effectiveness. The common procedures for ring structure identification against the noise background and probabilistic-deterministic methods for recognizing the desired targets in complex media are presented in Khesin and Eppelbaum (1997), Eppelbaum et al. (2003), and Eppelbaum (2007b). For integrated analysis of different geophysical fields (including GPR images) intended

  6. The Cannery Formation--Devonian to Early Permian arc-marginal deposits within the Alexander Terrane, Southeastern Alaska

    Science.gov (United States)

    Karl, Susan M.; Layer, Paul W.; Harris, Anita G.; Haeussler, Peter J.; Murchey, Benita L.

    2011-01-01

    cherts on both Admiralty and Kupreanof Islands contain radiolarians as young as Permian, the age of the Cannery Formation is herein extended to Late Devonian through early Permian, to include the early Permian rocks exposed in its type locality. The Cannery Formation is folded and faulted, and its stratigraphic thickness is unknown but inferred to be several hundred meters. The Cannery Formation represents an extended period of marine deposition in moderately deep water, with slow rates of deposition and limited clastic input during Devonian through Pennsylvanian time and increasing argillaceous, volcaniclastic, and bioclastic input during the Permian. The Cannery Formation comprises upper Paleozoic rocks in the Alexander terrane of southeastern Alaska. In the pre-Permian upper Paleozoic, the tectonic setting of the Alexander terrane consisted of two or more evolved oceanic arcs. The lower Permian section is represented by a distinctive suite of rocks in the Alexander terrane, which includes sedimentary and volcanic rocks containing early Permian fossils, metamorphosed rocks with early Permian cooling ages, and intrusive rocks with early Permian cooling ages, that form discrete northwest-trending belts. After restoration of 180 km of dextral displacement of the Chilkat-Chichagof block on the Chatham Strait Fault, these belts consist, from northeast to southwest, of (1) bedded chert, siliceous argillite, volcaniclastic turbidites, pillow basalt, and limestone of the Cannery Formation and the Porcupine Slate of Gilbert and others (1987); (2) greenschist-facies Paleozoic metasedimentary and metavolcanic rocks that have Permian cooling ages; (3) silty limestone and calcareous argillite interbedded with pillow basalt and volcaniclastic rocks of the Halleck Formation and the William Henry Bay area; and (4) intermediate-composition and syenitic plutons. These belts correspond to components of an accretionary complex, contemporary metamorphic rocks, forearc-basin deposits,

  7. Paleomagnetism of Early Paleozoic Rocks from the de Long Archipelago and Tectonics of the New Siberian Islands Terrane

    Science.gov (United States)

    Metelkin, D. V.; Chernova, A. I.; Matushkin, N. Y.; Vernikovskiy, V. A.

    2017-12-01

    The De Long archipelago is located to the north of the Anjou archipelago as a part of a large group between the Laptev Sea and the East Siberian Sea - the New Siberian Islands and consists of Jeannette Island, Bennett Island and Henrietta Island. These islands have been shown to be part of a single continental terrane, whose tectonic history was independent of other continental masses at least since the Ordovician. Paleomagnetic and precise geological data for the De Long archipelago were absent until recently. Only in 2013 special international field trips to the De Long Islands could be organized and geological, isotope-geochronological and paleomagnetic studies were carried out.On Jeannette Island a volcanic-sedimentary sequence intruded by mafic dikes was described. The age of these dikes is more likely Early Ordovician, close to 480 Ma, as evidenced by the results of our 40Ar/39Ar and paleomagnetic investigations of the dolerites as well as the result from detrital zircons in the host rocks published before. On Bennett Island, there are widespread Cambrian-Ordovician mainly terrigenous rocks. Paleomagnetic results from these rocks characterize the paleogeographic position of the De Long archipelago at 465 Ma and perhaps at 530 Ma, although there is no evidence for the primary origin of magnetization for the latter. On Henrietta Island the Early Cambrian volcanic-sedimentary section was investigated. A paleomagnetic pole for 520 Ma was obtained and confirmed by new 40Ar/39Ar results. Adding to our previous paleomagnetic data for the Anjou archipelago the extended variant of the apparent polar wander path for the New Siberian Island terrane was created. The established paleolatitudes define its location in the equatorial and subtropical zone no higher than 40 degrees during the Early Paleozoic. Because there are no good confirmations for true polarity and related geographic hemisphere we present two possibilities for tectonic reconstruction. But both these

  8. Paleomagnetic data from the Caborca terrane, Mexico: Implications for Cordilleran tectonics and the Mojave-Sonora megashear hypothesis

    Science.gov (United States)

    Molina Garza, Roberto S.; Geissman, John W.

    1999-04-01

    Two ancient magnetizations have been isolated in rocks of the Caborca terrane, northwest Mexico. The characteristic magnetizations of Neoproterozoic and Paleozoic miogeoclinal shelf-strata, arc-derived Lower Jurassic marine strata, and Jurassic volcanic and volcaniclastic rocks are of dual polarity and east-northeast declination (or south-southwest) and shallow inclination. Magnetizations in Neoproterozoic and Paleozoic miogeoclinal strata are interpreted as secondary (J*) and to be of similar age to those observed in Lower and Middle Jurassic rocks. Remanence acquisition is bracketed between about 190 and 160 Ma. The overall mean (D=15.0°, I=8.5° n=38 sites; six localities; k=19.1, α95=5.5°) suggests a moderate to large clockwise rotation of 12 to 50° (depending on reference direction assumed) of the Caborca terrane, and rocks of the Sonoran segment of the Cordilleran volcanic arc, with respect to the North America craton. When compared with expected inclinations, observed values are not anomalously steep, arguing against statistically significant southward latitudinal displacement of the Caborca block after remanence acquisition. Late Cretaceous intrusions yield primary, dual-polarity steep inclination ``K'' magnetizations (D=341.4°, I=52.3° n=10 sites; five localities; k=38.3, α95=7.9°) and have locally remagnetized Neoproterozoic and Jurassic strata. When present, secondary (K*) magnetizations in Neoproterozoic strata are of higher coercivity and higher unblocking temperature than the characteristic (J*) magnetization. Importantly, the regional internal consistency of data for Late Cretaceous intrusions suggests that effects of Tertiary tilt or rotation about a vertical axis over the broad region sampled (~5000 km2) are not substantial. Late Cretaceous primary (K) magnetizations and secondary (K*) magnetizations yield a combined mean of D=348.1°, I=50.7° (N=10 localities; 47 sites; k=53.5, α95=6.7°), indicating at most small (displacement is near

  9. Gravity and magnetic survey of the Oaxaca city region: Cenozoic horst-and-graben structure superimposed on the Oaxaca-Juarez terrane boundary, southern Mexico

    Science.gov (United States)

    Campos-Enríquez, J. O.; Belmonte-Jiménez, S. I.; Keppie, J. D.; Ortega-Gutiérrez, F.; Arzate, J. A.; Martínez-Silva, J.; Martínez-Serrano, R. G.

    2010-04-01

    A geophysical survey of the Oaxaca Fault along the north-trending Etla and Zaachila valleys area, southern Mexico, shows a series of NNW-SSE Bouguer and magnetic anomalies with steeper gradients towards the east. The Oaxaca Fault represents Tertiary extensional reactivation of the Juarez shear zone that constitutes the boundary between the Oaxaca and Juárez terranes. Cooperative interpretation of six combined gravity and magnetic NE-SW profiles perpendicular to the valleys indicates the presence of a composite depression comprising three N-S sub-basins: the northern Etla and southern Zaachila sub-basins separated by the Atzompa sub-basin. The Etla sub-basin is bounded by the moderately E-dipping, Etla Fault and the more steeply W-dipping Oaxaca Fault, which together constitute a graben that continues southwards into the Atzompa graben. The deeper Zaachila sub-basin, south of Oaxaca city, is a wide V-shaped graben with a horst in the middle. The new geophysical data suggest that the Oaxaca-Juarez terrane boundary is displaced sinistrally ca. 20 km along the E-W Donají Fault, which defines the northern boundary of the Zaachila sub-basin. On the other hand, the Oaxaca Fault may either continue unbroken southwards along the western margin of the horst in the Zaachila sub-basin or be offset along with the terrane boundary. The sinistral movement may have taken place either during the Late Mesozoic-Early Cenozoic, Laramide Orogeny as a lateral ramp in the thrust plane or under Miocene-Pliocene, NE-SW extension. The former suggests that the Donají Fault is a transcurrent fault, whereas the latter implies that it is a transfer fault. The models imply that originally the suture was continuous south of the Donaji Fault and provide a constraint for the accretion of the Oaxaca and Juarez terranes.

  10. Early Cretaceous I-type granites in the Tengchong terrane: New constraints on the late Mesozoic tectonic evolution of southwestern China

    Directory of Open Access Journals (Sweden)

    Yi Fang

    2018-03-01

    Full Text Available The Early Cretaceous granitoids that are widespread in the Tengchong terrane of Southwest China play a critical role in understanding the tectonic framework associated with the Tethyan oceans. In this study, we present a detailed description of zircon U–Pb ages, whole-rock geochemistry and Hf isotopes for the Laoxiangkeng pluton in the eastern Tengchong terrane and elucidate their petrogenesis and geodynamic implications. Zircon U–Pb dating of the Laoxiangkeng pluton yields ages of 114 ± 1 Ma and 115 ± 1 Ma, which imply an Early Cretaceous magmatic event. The Laoxiangkeng pluton enriched in Si and Na, is calc-alkaline and metaluminous, and has the characteristics of highly fractionated I-type granites. Zircons from the pluton have calculated εHf(t values of −12.7 to −3.7 and two-stage model ages of 1327–1974 Ma, respectively, indicating a mixed source of partial melting of Paleo-Neoproterozoic crust-derived compositions with some inputs of mantle-derived magmas. By integrating all available data for the regional tectonic evolution of the eastern Tethys tectonic domain, we conclude that the Early Cretaceous magmatism in the Tengchong terrane was produced by the northeastward subduction of the Meso-Tethyan Bangong–Nujiang Ocean.

  11. The tectono-magmatic evolution of the occidental terrane and the Paraiba do Sul Klippe within the Neoproterozoic Ribeira orogenic Belt, Southeastern Brazil

    International Nuclear Information System (INIS)

    Valladares, Claudia Sayao; Duarte, Beatriz Paschoal; Heilbron, Monica; Ragatky, Diana

    2000-01-01

    The occidental Terrane is envisaged as the eastern/southeastern reworked margin of the Sao Francisco/Rio de la Plata plate associated with and E-trending subduction under the Congo plate. The Paraiba do Sul Klippe is part of the Oriental Terrane, envisaged as a portion of the Congo plate. A collisional-stage resulted in intense westward deformation of the Occidental Terrane under intermediate pressure metamorphism (syn-D1+D2 events). A late-collisional stage resulted in subvertical folding and steep shear zones (D3 event). Both stages were associated with voluminous crustal-derived granites. U-Pb and Sm-Nd geochronology as well as geochemical and structural data point to three magmatic episodes: a syn-collisional stage 1; a syn-collisional stage 2; and a late-collisional stage. This paper presents a magmatic evolutionary model for this crustal segment of the Ribeira orogenic belt based on new geological data of Brasiliano granites and data available in the literature. (author)

  12. Petrography and geochronology (U/Pb-Sm/Nd) the Passagem Granite, Pensamiento Granitoid Complex, Paragua Terrane, SW Amazon Craton, Mato Grosso, Brazil

    International Nuclear Information System (INIS)

    Jesus, Gisely Carmo de; Sousa, Maria Zelia Aguiar de; Ruiz, Amarildo Salina; Matos, Joao Batista de

    2010-01-01

    The Passagem granite includes stocks, plugs and dikes located in the Ricardo Franco hill - Vila Bela da Santissima Trindade region - state of Mato Grosso, central Brazil. The Passagem Granite is included in the Paragua terrane - SW Amazonian Craton. It consists of isotropic monzogranite, sienogranite and more rarely granodiorites with leucocratic dark gray to white color. These rocks range from hypidomorphic inequigranular to xenomorphic texture, fine to medium grained. Biotite is the only primary mafic present as essential phase and characterize an expanded slightly acid sequence formed by a sub-alkaline magmatism of high-potassium calc-alkaline, slightly peraluminous composition from arc magmatic tectonic environment during a post-collisional period. Mechanism of fractional crystallization of plagioclase, biotite, titanite, apatite and zircon associated with simultaneous crustal assimilation are suggested for the evolution of these rocks. The results support the hypothesis of a post-collisional magmatism in the Paragua terrane at 1284 +- 20 Ma corresponding to the crystallization age of the Passagem granite. This paper propose that Passagem Granite represents as an extension in Brazilian terrane of the Pensamiento Granitoid Complex. (author)

  13. Emission of pesticides during drilling and deposition in adjacent areas

    Directory of Open Access Journals (Sweden)

    Heimbach, Udo

    2014-02-01

    Full Text Available In seven experiments seeds of maize, oil seed rape and barley, treated with neonicotinoids, were sown using pneumatic drilling equipment with deflectors attached in case of pneumatic suction systems. Directly adjacent to the drilled area of usually about 50 m width were replicated areas with bare soil as well as with crops. During maize (Zea mays drilling flowering oil seed rape (Brassica napus and during drilling of barley (Hordeum vulgare and oil seed rape flowering white mustard (Sinapis alba was adjacent. The amount of residues in the adjacent non crop areas in Petri dishes being distributed on the bare soil declined only slowly from 1 to 20 m distance from the area drilled. Seed batches with more abrasion and higher content of active substances in the dust resulted in higher residues off crop. After drilling of maize in four experiments in Petri dishes in adjacent non crop areas in 1-5 m distance between 0.02 and 0.40 g a.s./ha of neonicotinoids and in the adjacent oil seed rape a total of 0.05–0.80 g a.s./ha were detected. After drilling oil seed rape or barley these values were only 0.02–0.06 g a.s./ha in Petri dishes in non crop areas and 0.03-0.08 g a.s./ha in total in adjacent white mustard. In gauze net samplers installed vertically in 3 m distance in non crop areas up to seven times higher values were detected compared to Petri dishes.

  14. Modeling fires in adjacent ship compartments with computational fluid dynamics

    International Nuclear Information System (INIS)

    Wix, S.D.; Cole, J.K.; Koski, J.A.

    1998-01-01

    This paper presents an analysis of the thermal effects on radioactive (RAM) transportation pack ages with a fire in an adjacent compartment. An assumption for this analysis is that the adjacent hold fire is some sort of engine room fire. Computational fluid dynamics (CFD) analysis tools were used to perform the analysis in order to include convective heat transfer effects. The analysis results were compared to experimental data gathered in a series of tests on the United States Coast Guard ship Mayo Lykes located at Mobile, Alabama. (authors)

  15. Nonlinear spin wave coupling in adjacent magnonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Sadovnikov, A. V., E-mail: sadovnikovav@gmail.com; Nikitov, S. A. [Laboratory “Metamaterials,” Saratov State University, Saratov 410012 (Russian Federation); Kotel' nikov Institute of Radioengineering and Electronics, Russian Academy of Sciences, Moscow 125009 (Russian Federation); Beginin, E. N.; Morozova, M. A.; Sharaevskii, Yu. P.; Grishin, S. V.; Sheshukova, S. E. [Laboratory “Metamaterials,” Saratov State University, Saratov 410012 (Russian Federation)

    2016-07-25

    We have experimentally studied the coupling of spin waves in the adjacent magnonic crystals. Space- and time-resolved Brillouin light-scattering spectroscopy is used to demonstrate the frequency and intensity dependent spin-wave energy exchange between the side-coupled magnonic crystals. The experiments and the numerical simulation of spin wave propagation in the coupled periodic structures show that the nonlinear phase shift of spin wave in the adjacent magnonic crystals leads to the nonlinear switching regime at the frequencies near the forbidden magnonic gap. The proposed side-coupled magnonic crystals represent a significant advance towards the all-magnonic signal processing in the integrated magnonic circuits.

  16. Nonlinear spin wave coupling in adjacent magnonic crystals

    International Nuclear Information System (INIS)

    Sadovnikov, A. V.; Nikitov, S. A.; Beginin, E. N.; Morozova, M. A.; Sharaevskii, Yu. P.; Grishin, S. V.; Sheshukova, S. E.

    2016-01-01

    We have experimentally studied the coupling of spin waves in the adjacent magnonic crystals. Space- and time-resolved Brillouin light-scattering spectroscopy is used to demonstrate the frequency and intensity dependent spin-wave energy exchange between the side-coupled magnonic crystals. The experiments and the numerical simulation of spin wave propagation in the coupled periodic structures show that the nonlinear phase shift of spin wave in the adjacent magnonic crystals leads to the nonlinear switching regime at the frequencies near the forbidden magnonic gap. The proposed side-coupled magnonic crystals represent a significant advance towards the all-magnonic signal processing in the integrated magnonic circuits.

  17. Ancient terrane boundaries as probable seismic hazards: A case study from the northern boundary of the Eastern Ghats Belt, India

    Directory of Open Access Journals (Sweden)

    Saibal Gupta

    2014-01-01

    Full Text Available In the eastern part of the Indian shield, late Paleozoic–Mesozoic sedimentary rocks of the Talchir Basin lie precisely along a contact of Neoproterozoic age between granulites of the Eastern Ghats Mobile Belt (EGMB and amphibolite facies rocks of the Rengali Province. At present, the northern part of the basin experiences periodic seismicity by reactivation of faults located both within the basin, and in the Rengali Province to the north. Detailed gravity data collected across the basin show that Bouguer anomalies decrease from the EGMB (∼+15 mGal, through the basin (∼−10 mGal, into the Rengali Province (∼−15 mGal. The data are consistent with the reportedly uncompensated nature of the EGMB, and indicate that the crust below the Rengali Province has a cratonic gravity signature. The contact between the two domains with distinct sub-surface structure, inferred from gravity data, coincides with the North Orissa Boundary Fault (NOBF that defines the northern boundary of the Talchir Basin. Post-Gondwana faults are also localized along the northern margin of the basin, and present-day seismic tremors also have epicenters close to the NOBF. This indicates that the NOBF was formed by reactivation of a Neoproterozoic terrane boundary, and continues to be susceptible to seismic activity even at the present-day.

  18. Nd-Sr isotopic geochemistry and U-Pb geochronology of the Fe granitic gneiss and Lajedo Granodiorite: implications for paleoproterozoic evolution of the Mineiro Belt, southern Sao Francisco craton, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, Wilson [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Geociencias. Centro de Pesquisas Geocronologicas]. E-mail: wteixeir@usp.br; Avila, Ciro Alexandre [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Museu Nacional. Dept. de Geologia e Paleontologia]. E-mail: avila@mn.ufrj.br; Nunes, Luciana Cabral [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Geociencias]. E-mail: luciana@igc.usp.br

    2008-07-01

    The Fe granitic gneiss and Lajedo granodiorite belong to a voluminous felsic-mafic plutonism, tectonically linked to Paleoproterozoic magmatic evolution of the Mineiro Belt, southern portion of the Sao Francisco Craton, central-eastern Brazil. The Fe pluton is located north of the Lenheiros shear zone and is intrusive with respect to the Rio das Mortes greenstone belt and pyroxenite - gabbroic bodies, as indicated by xenoliths of gneiss and amphibolite, in the first case, and pyroxenite in the latter. The Lajedo granodiorite is located south of the Lenheiros shear zone and cuts the metamafic rocks of the Forro peridotite - pyroxenite and mafic and intermediate rocks of the Nazareno greenstone belt, as evidenced by xenoliths from the latter unit. The modal composition of the Fe granitic gneiss lies within the ranges of monzogranite and syenogranite. It is peraluminous and shows a large variation in K{sub 2}O content, which implies a middle-K calc-alkaline to high-K calc-alkaline tendency. The Lajedo modal composition is consistent with granodioritic and tonalitic compositions. It indicates a predominantly peraluminous composition and calc-alkaline character. The U-Pb zircon crystallization age of the Fe granitic gneiss is 2191 {+-} 9 Ma, whereas the Lajedo granodiorite yields 2208 {+-} 26 Ma. The Nd/Sr characteristics of the Fe and Lajedo plutons are consistent with mixtures of enriched mantle (EMI-type), DMM and crustal components during magma genesis in a plutonic arc setting, while the low {sup 87}Sr/{sup 86}Sri ratios point to contribution of mafic rock protoliths during magma genesis. This is also in accordance with the characteristic xenoliths observed within the investigated plutons from the Nazareno and Rio das Mortes greenstone belts. The Fe granitic gneiss and Lajedo granodiorite show tectonic characteristics which are comparable to those of nearby coeval plutons: Brito quartz-diorite (2221 +- 2 Ma), Brumado de Cima granodiorite (2219 {+-} 2 Ma), Brumado

  19. Nd-Sr isotopic geochemistry and U-Pb geochronology of the Fe granitic gneiss and Lajedo Granodiorite: implications for paleoproterozoic evolution of the Mineiro Belt, southern Sao Francisco craton, Brazil

    International Nuclear Information System (INIS)

    Teixeira, Wilson; Avila, Ciro Alexandre; Nunes, Luciana Cabral

    2008-01-01

    The Fe granitic gneiss and Lajedo granodiorite belong to a voluminous felsic-mafic plutonism, tectonically linked to Paleoproterozoic magmatic evolution of the Mineiro Belt, southern portion of the Sao Francisco Craton, central-eastern Brazil. The Fe pluton is located north of the Lenheiros shear zone and is intrusive with respect to the Rio das Mortes greenstone belt and pyroxenite - gabbroic bodies, as indicated by xenoliths of gneiss and amphibolite, in the first case, and pyroxenite in the latter. The Lajedo granodiorite is located south of the Lenheiros shear zone and cuts the metamafic rocks of the Forro peridotite - pyroxenite and mafic and intermediate rocks of the Nazareno greenstone belt, as evidenced by xenoliths from the latter unit. The modal composition of the Fe granitic gneiss lies within the ranges of monzogranite and syenogranite. It is peraluminous and shows a large variation in K 2 O content, which implies a middle-K calc-alkaline to high-K calc-alkaline tendency. The Lajedo modal composition is consistent with granodioritic and tonalitic compositions. It indicates a predominantly peraluminous composition and calc-alkaline character. The U-Pb zircon crystallization age of the Fe granitic gneiss is 2191 ± 9 Ma, whereas the Lajedo granodiorite yields 2208 ± 26 Ma. The Nd/Sr characteristics of the Fe and Lajedo plutons are consistent with mixtures of enriched mantle (EMI-type), DMM and crustal components during magma genesis in a plutonic arc setting, while the low 87 Sr/ 86 Sri ratios point to contribution of mafic rock protoliths during magma genesis. This is also in accordance with the characteristic xenoliths observed within the investigated plutons from the Nazareno and Rio das Mortes greenstone belts. The Fe granitic gneiss and Lajedo granodiorite show tectonic characteristics which are comparable to those of nearby coeval plutons: Brito quartz-diorite (2221 +- 2 Ma), Brumado de Cima granodiorite (2219 ± 2 Ma), Brumado de Baixo

  20. Natural and mining-related mercury in an orogenic greywacke terrane, South Island, New Zealand

    International Nuclear Information System (INIS)

    Holley, E.A.; Craw, D.; Kim, J.P.

    2010-01-01

    Mercury (Hg) is naturally present in warm springs and mesothermal (orogenic) gold-bearing quartz vein systems in the South Island of New Zealand. Mercury amalgamation was used historically in ore processing at gold (Au) mines, resulting in composite natural and anthropogenic Hg signatures at these sites. This study compares natural Hg enrichment of the Au vein systems, residual anthropogenic Hg added for amalgamation, and enrichment of naturally present Hg during ore processing. Mercury concentration data are presented for solids and water at historic mine sites, the modern Macraes mine, fault-related warm springs, and zones of naturally occurring cinnabar and Hg-bearing Au. Arsenic (As) concentrations are also presented, as As is the most environmentally significant element in this tectonic setting. Tailings and processing residues at historic mine sites (Blackwater mine, West Coast; Golden Point and Golden Bar, Hyde-Macraes shear zone) contain up to 1000 mg/kg Hg, and in adjacent surface waters Hg is at or slightly above background from 0.6 to 0.8 ng/L. Relative to South Island Hg, As is more environmentally significant: solid wastes at some historic mine and mineral processing sites contain up to 30.5 wt% As due to enrichment of natural As in mineralised rocks. Shallow groundwater and processing waters at the modern Macraes mine are up to 0.01 mg/L Hg due to natural Hg in mineralised rocks, and no significant Hg elevation is evident in nearby surface waters, which are 3 to 10 4 times higher than primary ore, and Hg is disproportionally increased relative to As, indicating that much of the Hg was added during the amalgamation process. Natural cinnabar deposition from warm springs results in localised, strongly elevated Hg, equal to or less than the Hg contents in historic mine processing residues. Warm spring precipitates are up to 111 mg/kg Hg and waters are 0.3 μg/L Hg, comparable to data reported for active North Island geothermal (epithermal-style) systems

  1. An evolving tectonic environment of Late Carboniferous to Early Permian granitic plutons in the Chinese Altai and Eastern Junggar terranes, Central Asian Orogenic Belt, NW China

    Science.gov (United States)

    Zhang, Chen; Liu, Dongdong; Luo, Qun; Liu, Luofu; Zhang, Yunzhao; Zhu, Deyu; Wang, Pengfei; Dai, Quanqi

    2018-06-01

    The Central Asian Orogenic Belt (CAOB) represents one of the most important sites of juvenile crustal growth during the Phanerozoic. Located in the central part of the CAOB, the Chinese Altai and Eastern Junggar terranes record the collisional processes between the peri-Siberian and Kazakhstan orogenic systems. However, the precise timing of collision between the two terranes remains controversial. The Wukuli and Kadelat plutons in the Chinese Altai belt are dated at ∼305 and ∼280 Ma respectively, whereas the Aketas pluton in the Eastern Junggar terrane is dated at ∼308 Ma. Granites from the Wukuli and Kadelat plutons are strongly peraluminous (A/CNK > 1.1), and are characterized by low Al2O3, Na2O, MnO, MgO, CaO and heavy rare earth element (HREE) contents, but with high SiO2, K2O and Rb contents as well as high Rb/Sr ratios. Granites from the Wukuli pluton have low εNd(t) and εHf(t) values of -3.7 to -3.4 and -9.7 to +4.9, whereas those from the Kadelat pluton have values of -3.6 to -3.4 and -8.0 to +2.6. These features suggest S-type affinity for the Wukuli and Kadelat plutons with magma derivation through partial melting of Mesoproterozoic metasediments. The Aketas pluton is composed of weakly peraluminous quartz monzonites that have A/CNK values ranging from 0.92 to 1.08, with high Na2O, Sr, and Sr/Y, and low Y, Yb, Nb, and Ta. These rocks display positive εNd(t) (+4.8 to +6.4) and εHf(t) (+9.7 to +14.6) values, and low initial 87Sr/86Sr ratios (0.703357-0.703868), similar to modern adakites, suggesting that the quartz monzonites were derived from the partial melting of lower crustal material. The geochemical characteristics suggest that the Aketas pluton was formed in a subduction-related setting, the Wukuli pluton in a syn-collisional setting, and the Kadelat pluton in the subsequent post-orogenic strike-slip-related setting. In combination with data from other granitoids in these two terranes, the Aketas pluton represents the youngest record of

  2. Timing of metamorphism of the Lansang gneiss and implications for left-lateral motion along the Mae Ping (Wang Chao) strike-slip fault, Thailand

    Science.gov (United States)

    Palin, R. M.; Searle, M. P.; Morley, C. K.; Charusiri, P.; Horstwood, M. S. A.; Roberts, N. M. W.

    2013-10-01

    The Mae Ping fault (MPF), western Thailand, exhibits dominantly left-lateral strike-slip motion and stretches for >600 km, reportedly branching off the right-lateral Sagaing fault in Myanmar and extending southeast towards Cambodia. Previous studies have suggested that the fault assisted the large-scale extrusion of Sundaland that occurred during the Late Eocene-Early Oligocene, with a geological offset of ˜120-150 km estimated from displaced high-grade gneisses and granites of the Chiang Mai-Lincang belt. Exposures of high-grade orthogneiss in the Lansang National Park, part of this belt, locally contain strong mylonitic textures and are bounded by strike-slip ductile shear zones and brittle faults. Geochronological analysis of monazite from a sample of sheared biotite-K-feldspar orthogneiss suggests two episodes of crystallization, with core regions documenting Th-Pb ages between c. 123 and c. 114 Ma and rim regions documenting a significantly younger age range between c. 45-37 Ma. These data are interpreted to represent possible magmatic protolith emplacement for the Lansang orthogneiss during the Early Cretaceous, with a later episode of metamorphism occurring during the Eocene. Textural relationships provided by in situ analysis suggest that ductile shearing along the MPF occurred during the latter stages of, or after, this metamorphic event. In addition, monazite analyzed from an undeformed garnet-two-mica granite dyke intruding metamorphic units at Bhumipol Lake outside of the Mae Ping shear zone produced a Th-Pb age of 66.2 ± 1.6 Ma. This age is interpreted to date the timing of dyke emplacement, implying that the MPF cuts through earlier formed magmatic and high-grade metamorphic rocks. These new data, when combined with regional mapping and earlier geochronological work, show that neither metamorphism, nor regional cooling, was directly related to strike-slip motion.

  3. Herpetology of the American Madrean Archipelago and adjacent valleys

    Science.gov (United States)

    Lawrence L. C. Jones

    2005-01-01

    Approximately 110 species of amphibians (18 frogs and toads, and 1 salamander) and reptiles (47 snakes, 39 lizards, and 5 turtles) are known from the American Madrean Archipelago and adjacent valleys. The high diversity of the herpetofauna comes from a variety of factors, including a convergence of biotic communities representing deserts, grasslands, and mountains....

  4. Developmental tumors and adjacent cortical dysplasia: single or dual pathology?

    Science.gov (United States)

    Palmini, André; Paglioli, Eliseu; Silva, Vinicius Duval

    2013-12-01

    Developmental tumors often lead to refractory partial seizures and constitute a well-defined, surgically remediable epilepsy syndrome. Dysplastic features are often associated with these tumors, and their significance carries both practical and conceptual relevance. If associated focal cortical dysplasia (FCD) relates to the extent of the epileptogenic tissue, then presurgical evaluation and surgical strategies should target both the tumor and the surrounding dyslaminated cortex. Furthermore, the association has been included in the recently revised classification of FCD and the epileptogenicity of this associated dysplastic tissue is crucial to validate such revision. In addition to the possibility of representing dual pathology, the association of developmental tumors and adjacent dysplasia may instead represent a single developmental lesion with distinct parts distributed along a histopathologic continuum. Moreover, the possibility that this adjacent dyslamination is of minor epileptogenic relevance should also be entertained. Surgical data show that complete resection of the solid tumors and immediately adjacent tissue harboring satellites may disrupt epileptogenic networks and lead to high rates of seizure freedom, challenging the epileptogenic relevance of more extensive adjacent dyslaminated cortex. Whether the latter is a primary or secondary abnormality and whether dyslaminated cortex in the context of a second lesion may produce seizures after complete resection of the main lesion is still to be proven. Wiley Periodicals, Inc. © 2013 International League Against Epilepsy.

  5. The dynamics of microtidal lagoons and adjacent coasts

    NARCIS (Netherlands)

    Stive, M.J.F.; Capobianco, M.; Wang, Z.B.; Ruol, P.

    1996-01-01

    We have formulated an aggregated-scale behaviour-model for the interaction between a tidal basin and its adjacent coastal environment, without adopting a priory assumptions about their independent dynamic equilibrium behaviour. Necessarily so, the model combines observations and findings resuhing

  6. Do Mangroves Subsidize Carbon to Adjacent Mudflat Fish Communities?

    Science.gov (United States)

    Henkel, S.; Kasten, S.; Hartmann, J.; Staubwasser, M.; Hernandez, M. F.; West, L.; Midway, S. R.; Polito, M. J.

    2017-12-01

    Mangroves are often implicated as energetic sources for fisheries productivity. However, the validity of this connection still remains in contention. Stable isotopes may provide answers by tracking the use of specific basal carbon sources in fish and invertebrates living in mangrove-mudflat habitat mosaics. We analyzed 307 consumer samples representing n=44 fish and invertebrate species collected from mangrove forest creeks and adjacent mudflats in coastal Tanzania using bulk carbon and nitrogen stable isotope analysis. Given the proposed high productivity of mangrove habitats, we hypothesize that mudflat communities will have carbon stable isotope values similar to mangrove communities either through the flux of mangrove carbon into adjacent mudflats and/or via the movement of mudflat fish communities into and out of mangrove habitats. Alternatively, mangrove carbon is often refractory, which may result in mudflat communities with isotopic values that differ from those found in adjacent mangrove communities. This scenario would suggest limited carbon flow between mudflat and mangrove food webs and that the movement of fish into and out of mangrove habitats is related to shelter from predation more than feeding. Data analysis is ongoing to test these competing hypotheses. By understanding the contribution of mangrove carbon to adjacent habitats, managers in Tanzania can make better informed decisions regarding the protection of mangroves and the local fisheries, which are a crucial source of income and food.

  7. Measurement Methods to Determine Air Leakage Between Adjacent Zones

    Energy Technology Data Exchange (ETDEWEB)

    Hult, Erin L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dickerhoff, Darryl J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Price, Phillip N. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-09-01

    Air leakage between adjacent zones of a building can lead to indoor air quality and energy efficiency concerns, however there is no existing standard for measuring inter-zonal leakage. In this study, synthesized data and field measurements are analyzed in order to explore the uncertainty associated with different methods for collecting and analyzing fan pressurization measurements to calculate interzone leakage.

  8. Optimal induced universal graphs and adjacency labeling for trees

    DEFF Research Database (Denmark)

    Alstrup, Stephen; Dahlgaard, Søren; Knudsen, Mathias Bæk Tejs

    2015-01-01

    bound. The lower bound and previously best upper bounds were presented in Alstrup and Rauhe (FOCS'02). Our upper bounds are obtained through a log2 n + O(1) labeling scheme for adjacency queries in forests. We hereby solve an open problem being raised repeatedly over decades, e.g. in Kannan, Naor...

  9. Investigating high zircon concentrations in the fine fraction of stream sediments draining the Pan-African Dahomeyan Terrane in Nigeria

    International Nuclear Information System (INIS)

    Key, Roger M.; Johnson, Christopher C.; Horstwood, Matthew S.A.; Lapworth, Dan J.; Knights, Katherine V.; Kemp, Simon J.; Watts, Michael; Gillespie, Martin; Adekanmi, Michael; Arisekola, Tunde

    2012-01-01

    Sixteen hundred stream sediments (<150 μm fraction) collected during regional geochemical surveys in central and SW Nigeria have high median and maximum concentrations of Zr that exceed corresponding Zr concentrations found in stream sediments collected from elsewhere in the World with similar bedrock geology. X-ray diffraction studies on a sub-set of the analysed stream sediments showed that Zr is predominantly found in detrital zircon grains. However, the main proximal source rocks (Pan-African ‘Older Granites’ of Nigeria and their Proterozoic migmatitic gneiss country rocks) are not enriched in zircon (or Zr). Nevertheless, U–Pb LA-ICP-MS dating with cathodoluminescence imaging on detrital zircons, both from stream sediment samples and underlying Pan-African ‘Older Granites’ confirms a local bedrock source for the stream sediment zircons. A combination of tropical/chemical weathering and continuous physical weathering, both by ‘wet season’ flash flooding and ‘dry season’ unidirectional winds are interpreted to have effectively broken down bedrock silicate minerals and removed much of the resultant clay phases, thereby increasing the Zr contents in stream sediments. The strong correlation between winnowing index (Th/Al) and Zr concentration across the study area support this interpretation. Therefore, ‘anomalous’ high values of Zr, as well as other elements concentrated in resistant ‘heavy’ minerals in Nigeria’s streams may not reflect proximal bedrock concentrations of these elements. This conclusion has important implications for using stream sediment chemistry as an exploration tool in Nigeria for primary metal deposits associated with heavy minerals.

  10. Cryopreserved embryo transfer: adjacent or non-adjacent to failed fresh long GnRH-agonist protocol IVF cycle.

    Science.gov (United States)

    Volodarsky-Perel, Alexander; Eldar-Geva, Talia; Holzer, Hananel E G; Schonberger, Oshrat; Reichman, Orna; Gal, Michael

    2017-03-01

    The optimal time to perform cryopreserved embryo transfer (CET) after a failed oocyte retrieval-embryo transfer (OR-ET) cycle is unknown. Similar clinical pregnancy rates were recently reported in immediate and delayed CET, performed after failed fresh OR-ET, in cycles with the gonadotrophin-releasing hormone (GnRH) antagonist protocol. This study compared outcomes of CET performed adjacently (<50 days, n = 67) and non-adjacently (≥50 to 120 days, n = 62) to the last OR-day of cycles with the GnRH agonist down-regulation protocol. Additional inclusion criteria were patients' age 20-38 years, the transfer of only 1-2 cryopreserved embryos, one treatment cycle per patient and artificial preparation for CET. Significantly higher implantation, clinical pregnancy and live birth rates were found in the non-adjacent group than in the adjacent group: 30.5% versus 11.3% (P = 0.001), 41.9% versus 17.9% (P = 0.003) and 32.3% versus 13.4% (P = 0.01), respectively. These results support the postponement of CET after a failed OR-ET for at least one menstrual cycle, when a preceding long GnRH-agonist protocol is used. Copyright © 2016 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

  11. The metallogeny of Late Triassic rifting of the Alexander terrane in southeastern Alaska and northwestern British Columbia

    Science.gov (United States)

    Taylor, C.D.; Premo, W.R.; Meier, A.L.; Taggart, J.E.

    2008-01-01

    A belt of unusual volcanogenic massive sulfide (VMS) occurrences is located along the eastern margin of the Alexander terrane throughout southeastern Alaska and northwestern British Columbia and exhibits a range of characteristics consistent with a variety of syngenetic to epigenetic deposit types. Deposits within this belt include Greens Creek and Windy Craggy, the economically most significant VMS deposit in Alaska and the largest in North America, respectively. The occurrences are hosted by a discontinuously exposed, 800-km-long belt of rocks that consist of a 200- to 800-m-thick sequence of conglomerate, limestone, marine elastic sedimentary rocks, and tuff intercalated with and overlain by a distinctive unit of mafic pyroclastic rocks and pillowed flows. Faunal data bracket the age of the host rocks between Anisian (Middle Triassic) and late Norian (late Late Triassic). This metallogenic belt is herein referred to as the Alexander Triassic metallogenic belt. The VMS occurrences show systematic differences in degree of structural control, chemistry, and stratigraphic setting along the Alexander Triassic metallogenic belt that suggest important spatial or temporal changes in the tectonic environment of formation. At the southern end of the belt, felsic volcanic rocks overlain by shallow-water limestones characterize the lower part of the sequence. In the southern and middle portion of the belt, a distinctive pebble conglomerate marks the base of the section and is indicative of high-energy deposition in a near slope or basin margin setting. At the northern end of the belt the conglomerates, limestones, and felsic volcanic rocks are absent and the belt is composed of deep-water sedimentary and mafic volcanic rocks. This northward change in depositional environment and lithofacies is accompanied by a northward transition from epithermal-like structurally controlled, discontinuous, vein- and pod-shaped, Pb-Zn-Ag-Ba-(Cu) occurrences with relatively simple mineralogy

  12. Detrital rutile geochemistry and thermometry from the Dabie orogen: Implications for source-sediment links in a UHPM terrane

    Science.gov (United States)

    Liu, Lei; Xiao, Yilin; Wörner, G.; Kronz, A.; Simon, K.; Hou, Zhenhui

    2014-08-01

    This study explores the potential of detrital rutile geochemistry and thermometry as a provenance tracer in rocks from the Central Dabie ultrahigh-pressure metamorphic (UHPM) zone in east-central China that formed during Triassic continental collision. Trace element data of 176 detrital rutile grains selected from local river sediments and 91 rutile grains from distinct bedrocks in the Shuanghe and Bixiling areas, obtained by both electron microprobe (EMP) and in situ LA-ICP-MS analyses, suggest that geochemical compositions and thermometry of detrital rutiles are comparable to those from their potential source rocks. After certification of the Cr-Nb discrimination method for the Central Dabie UHPM zone, we show that 29% of the detrital rutiles in the Shuanghe area were derived from metamafic sources whereas in the Bixiling area that it is up to 76%. Furthermore, the proportion of distinct types of detrital rutiles combined with modal abundances of rutile in metapelites and metamafic bedrocks can be used to estimate the proportion of different source lithologies. Based on this method the proportion of mafic source rocks was estimated to ∼10% at Shuanghe and >60% at Bixiling, respectively, which is consistent with the proportions of eclogite (the major rutile-bearing metamafic rock) distribution in the field. Therefore, the investigation of detrital rutiles is a potential way to evaluate the proportion of metamafic rocks and even to prospect for metamafic bodies in UHPM terranes. Zr-in-rutile temperatures were calculated at different pressures and compared with temperatures derived from rock-in rutiles and garnet-clinopyroxene Fe-Mg thermometers. Temperatures calculated for detrital rutiles range from 606 °C to 707 °C and 566 °C to 752 °C in Shuanghe and Bixiling, respectively, at P = 3 GPa with an average temperatures of ca. 630 °C for both areas. These temperature averages and ranges are similar to those calculated for rutiles from surrounding source rocks

  13. Silicate-Oxide Equilibria in the Wilson Lake Terrane, Labrador - Evidence for a Pre- Metamorphic Oxidizing Event

    Science.gov (United States)

    Korhonen, F. J.; Stout, J. H.

    2006-05-01

    The presence of Fe3+ and Ti in silicates and their presumed equilibration with Fe2+-Fe3+-Ti oxide minerals has long been recognized as an important factor in metamorphic phase equilibria. The Red Wine Mountains massif is a granulite facies unit in the Wilson Lake terrane of central Labrador, where this equilibration is especially important for estimating both temperature and fO2 during peak metamorphism. Peak assemblages are sapphirine + quartz, and orthopyroxene + sillimanite + quartz. The coexisting oxides, which are largely responsible for the pronounced aeromagnetic high of the massif, consist of nearly pure magnetite and an exsolved titanohematite. Estimates of fO2 based on magnetite + integrated titanohematite compositions are slightly below that defined by the pure magnetite-hematite buffer. This assemblage is also responsible for the magnetic signature of metagabbro and metanorite dikes, a fact which challenges the conventional wisdom that the high Fe3+ content of the host paragneisses was inherited from a highly oxidized ferruginous shale. We suggest here that prior to granulite facies metamorphism, an oxidizing hydrothermal event either coeval or following the emplacement of mafic dikes into the paragneiss host was responsible for the highly oxidized nature of the massif as a whole. Subsequent metamorphism then produced the observed assemblages. This scenario is supported by recent U-Pb zircon and monazite ages of ca. 1626 ± 10 Ma, which indicate that both metagabbro dikes and host paragneiss were metamorphosed at the same time. Dike emplacement and the oxidizing event must have preceded 1626 Ma. The implications of this pre-metamorphic oxidizing event is that Fe3+ becomes an inherent and fixed component in the chemical system during metamorphism. Phase relationships, preliminary thermodynamic modeling, and geothermobarometric constraints indicate that peak temperatures are lower than those previously determined for Fe3+-absent systems. More appropriate

  14. 33 CFR 148.217 - How can a State be designated as an adjacent coastal State?

    Science.gov (United States)

    2010-07-01

    ... an adjacent coastal State? 148.217 Section 148.217 Navigation and Navigable Waters COAST GUARD... General § 148.217 How can a State be designated as an adjacent coastal State? (a) Adjacent coastal States... as an adjacent coastal State in the notice may request to be designated as one if the environmental...

  15. Extraosseous Gaucher cell deposition without adjacent bone involvement.

    Science.gov (United States)

    Meyer, Brendan J; Mills, Anne M; Gaskin, Cree M

    2014-10-01

    Extraosseous Gaucher cell deposits are a rare complication of Gaucher disease that can mimic malignancy. We describe a case of Gaucher cell deposition in the subcutaneous soft tissues overlying the lower thoracic spine in an 18-year-old woman with known type III Gaucher disease. This case is unique in the literature because this subcutaneous Gaucher mass was not associated with extension from underlying bone involvement or clear lymph node origin. It demonstrated no discernible continuity with the adjacent thoracic spinous processes, the cortices of which appeared intact. Although patients with Gaucher disease are at increased risk of malignancy, Gaucher cell deposition should remain a differential consideration for soft tissue masses with or without adjacent bone involvement in patients with known Gaucher disease.

  16. A new nuclear safety programme for areas adjacent to Finland

    International Nuclear Information System (INIS)

    Varjoranta, T.

    1997-01-01

    The projects aimed at improving nuclear and radiation safety in areas adjacent to Finland have been compiled into one programme. The purpose of the programme is to promote activities that minimise accident risks at nuclear power plants and that improve preparedness for situations involving a risk. Nuclear materials are also to be kept under strict control. In the last few years, nuclear and radiation safety has clearly improved in areas adjacent to Finland. But work is still needed to reduce the remaining risks. The Finnish support programme comprises two very definite functions. On one hand, the programme acts as a catalyst for projects launched by the Russians themselves or by the Western partners together, and strives to pave the way for international financing projects. On the other hand, assistance is given as direct support for certain hand-picked projects. (orig.)

  17. Fish species diversity and conservation in Beijing and adjacent areas

    OpenAIRE

    Chunguang Zhang; Yahui Zhao; Yingchun Xing; Ruilu Guo; Qing Zhang; Yun Feng; Enyuan Fan

    2011-01-01

    Based on field surveys between 2002 and 2010, and fish collections in the National Zoological Museum, Institute of Zoology, Chinese Academy of Sciences, a total of 93 wild fish species including 12 in-troduced species had been recorded in Beijing and adjacent areas. Eighty five of these species, including some migratory and estuarine fishes, are native to the region. Only 43 native wild species were collected in our field work from 2002 to 2010. Compared with the historical records, nearly 50...

  18. Plutonium in soil adjacent to Rocky Flats plant

    International Nuclear Information System (INIS)

    Hume, M.W.; Illsley, C.T.

    1979-01-01

    In 1975, lawsuits were filed claiming contaminated lands adjacent to the plant. Five remote as well as 89 sites on lands under litigation were sampled using four sampling techniques at each site. An additional 71 sites were sampled using the Rockwell International technique. No results approached the EPA proposed guideline screening level of 200 mCi/km 2 , although numerous sites to the last of the plant exceed 2 d/m/g (10 mCi/km 2 )

  19. The Benguela upwelling ecosystem lies adjacent to the south ...

    African Journals Online (AJOL)

    denise

    The Benguela upwelling ecosystem lies adjacent to the south-western coast of Africa, from southern Angola. (15°S) to Cape Agulhas (35°S; Fig. 1). Ecologically, it is split into separate northern and southern sub- systems by a zone of intense perennial upwelling near. Lüderitz (26–27.5°S; Shannon 1985). As is charac-.

  20. Origin of an unusual monazite-xenotime gneiss, Hudson Highlands, New York: SHRIMP U-Pb geochronology and trace element geochemistry

    Science.gov (United States)

    Aleinikoff, John N.; Grauch, Richard I.; Mazdab, Frank K.; Kwak, Loretta; Fanning, C. Mark; Kamo, Sandra L.

    2012-01-01

    A pod of monazite-xenotime gneiss (MXG) occurs within Mesoproterozoic paragneiss, Hudson Highlands, New York. This outcrop also contains granite of the Crystal Lake pluton, which migmatized the paragneiss. Previously, monazite, xenotime, and zircon from MXG, plus detrital zircon from the paragneiss, and igneous zircon from the granite, were dated using multi-grain thermal ionization mass spectrometry (TIMS). New SEM imagery of dated samples reveals that all minerals contain cores and rims. Thus TIMS analyses comprise mixtures of age components and are geologically meaningless. New spot analyses by sensitive high resolution ion microprobe (SHRIMP) of small homogeneous areas on individual grains allows deconvolution of ages within complexly zoned grains.Xenotime cores from MXG formed during two episodes (1034 ± 10 and 1014 ± 3 Ma), whereas three episodes of rim formation are recorded (999 ± 7, 961 ± 11, and 874 ± 11 Ma). Monazite cores from MXG mostly formed at 1004 ± 4 Ma; rims formed at 994 ± 4, 913 ± 7, and 890 ± 7 Ma. Zircon from MXG is composed of oscillatory-zoned detrital cores (2000-1170 Ma), plus metamorphic rims (1008 ± 7, 985 ± 5, and ∼950 Ma). In addition, MXG contains an unusual zircon population composed of irregularly-zoned elongate cores dated at 1036 ± 5 Ma, considered to be the time of formation of MXG. The time of granite emplacement is dated by oscillatory-zoned igneous cores at 1058 ± 4 Ma, which provides a minimum age constraint for the time of deposition of the paragneiss.Selected trace elements, including all REE plus U and Th, provide geochemical evidence for the origin of MXG. MREE-enriched xenotime from MXG are dissimilar from typical HREE-enriched patterns of igneous xenotime. The presence of large negative Eu anomalies and high U and Th in monazite and xenotime are uncharacteristic of typical ore-forming hydrothermal processes. We conclude that MXG is the result of unusual metasomatic processes during high grade

  1. Investigation of Fault Zones In The Penninic Gneiss Complex of The Swiss Central Alps Using Tomograhic Inversion of The Seismic Wavefield Along Tunnels

    Science.gov (United States)

    Giese, R.; Klose, C.; Otto, P.; Selke, C.; Borm, G.

    Underground seismic investigations have been carried out since March 2000 in the Faido adit of the Gotthard Base Tunnel (Switzerland) and the Piora exploration adit. Both adits cut metamorphic rock formations of the Leventina and Lucomagno Gneiss Complexes. The seismic measurements in the Faido Adit were carried out every 200 m during the excavation work with the Integrated Seismic Imaging System (ISIS) developed by the GeoForschungsZentrum Potsdam in cooperation with Amberg Measuring Technique, Switzerland. This system provides high resolution seismic images via an array of stan- dard anchor rods containing 3D-geophones which can be installed routinely during the excavation process. The seismic source is a repetitive pneumatic impact hammer. For each measurement in the Faido adit, seismic energy was transmitted from 30 to 50 source points distributed along the tunnel wall at intervals of 1.0 to 1.5 m. In the Piora exploration adit a 2D grid of 441 source points distributed along a distance of 147 tunnel meters were measured. In both adits the shots were recorded by arrays of 8 to 16 three - component geophone anchor rods glued into 2 m deep boreholes at intervals of 9 m - 10 m. The total length of all profiles was about 850 m. Seismic sections show first P-wave energy at frequencies up to 2 kHz and S-wave energy up to 1.3 kHz. Reflection energy was observed from distances of up to 350 m for P-waves and 200 m for S-waves. The dominant frequencies of reflective energy were found between 600 and 800 Hz for P-waves and between 200 and 400 Hz for S-waves. The corresponding wave lengths were 8 to 10 m. We used the first arrival times of P- and S- waves to calculate tomographic inversions. The 2D-velocity models for P- and S-waves in the Faido adit revealed a near field of 2 to 3 m from the tunnel surface which is characterized by strong velocity variations: 3000 to 5700 m/s for P-wave velocity (Vp) and 2000 to 3000 m/s for S-wave velocity (Vs). High velocity zones

  2. Symmetry breaking of adjacent tracks in perpendicular recording system

    International Nuclear Information System (INIS)

    Xie Huang; Wei Dan

    2007-01-01

    The track density increase in a perpendicular magnetic recording system is limited by the adjacent-track interference (ATI). In this work, a composite micromagnetic simulation model of the read/write process is developed to analyse ATI by the symmetry of signal and noise in two adjacent W = 60 nm tracks with the track pitch of the order of 100 nm. Based on the two-dimensional medium noise distribution of dibit recording, it is found that the noise in the first and later recorded tracks start to be asymmetric when the track pitch is lower than 2 W; if the read width is limited within 2/3 of the write width, the asymmetry of noise appears when the track pitch is less than 1.5 W. At higher recording densities, the signal-to-noise ratio degradation is mainly due to the noise caused by the interference from the signal of the adjacent track. Side writing can be effectively eliminated by the use of a guard band whose width is at least half the track width

  3. Using BRDFs for accurate albedo calculations and adjacency effect corrections

    Energy Technology Data Exchange (ETDEWEB)

    Borel, C.C.; Gerstl, S.A.W.

    1996-09-01

    In this paper the authors discuss two uses of BRDFs in remote sensing: (1) in determining the clear sky top of the atmosphere (TOA) albedo, (2) in quantifying the effect of the BRDF on the adjacency point-spread function and on atmospheric corrections. The TOA spectral albedo is an important parameter retrieved by the Multi-angle Imaging Spectro-Radiometer (MISR). Its accuracy depends mainly on how well one can model the surface BRDF for many different situations. The authors present results from an algorithm which matches several semi-empirical functions to the nine MISR measured BRFs that are then numerically integrated to yield the clear sky TOA spectral albedo in four spectral channels. They show that absolute accuracies in the albedo of better than 1% are possible for the visible and better than 2% in the near infrared channels. Using a simplified extensive radiosity model, the authors show that the shape of the adjacency point-spread function (PSF) depends on the underlying surface BRDFs. The adjacency point-spread function at a given offset (x,y) from the center pixel is given by the integral of transmission-weighted products of BRDF and scattering phase function along the line of sight.

  4. Smarandachely Adjacent-Vertex-Distinguishing Proper Edge Chromatic Number of Cm∨Kn

    OpenAIRE

    Shunqin Liu

    2016-01-01

    According to different conditions, researchers have defined a great deal of coloring problems and the corresponding chromatic numbers. Such as, adjacent-vertex-distinguishing total chromatic number, adjacent-vertex-distinguishing proper edge chromatic number, smarandachely-adjacent-vertex-distinguishing proper edge chromatic number, smarandachely-adjacent-vertex-distinguishing proper total chromatic number. And we focus on the smarandachely adjacent-vertex-distinguishing proper edge chromatic...

  5. Geologic map of the Strawberry Butte 7.5’ quadrangle, Meagher County, Montana

    Science.gov (United States)

    Reynolds, Mitchell W.; Brandt, Theodore R.

    2017-06-19

    The 7.5′ Strawberry Butte quadrangle in Meagher County, Montana near the southwest margin of the Little Belt Mountains, encompasses two sharply different geologic terranes.  The northern three-quarters of the quadrangle are underlain mainly by Paleoproterozoic granite gneiss, across which Middle Cambrian sedimentary rocks rest unconformably.  An ancestral valley of probable late Eocene age, eroded northwest across the granite gneiss terrane, is filled with Oligocene basalt and overlying Miocene and Oligocene sandstone, siltstone, tuffaceous siltstone, and conglomerate.  The southern quarter of the quadrangle is underlain principally by deformed Mesoproterozoic sedimentary rocks of the Newland Formation, which are intruded by Eocene biotite hornblende dacite dikes.  In this southern terrane, Tertiary strata are exposed only in a limited area near the southeast margin of the quadrangle.  The distinct terranes are juxtaposed along the Volcano Valley fault zone—a zone of recurrent crustal movement beginning possibly in Mesoproterozoic time and certainly established from Neoproterozoic–Early Cambrian to late Tertiary time.  Movement along the fault zone has included normal faulting, the southern terrane faulted down relative to the northern terrane, some reverse faulting as the southern terrane later moved up against the northern terrane, and lateral movement during which the southern terrane likely moved west relative to the northern terrane.  Near the eastern margin of the quadrangle, the Newland Formation is locally the host of stratabound sulfide mineralization adjacent to the fault zone; west along the fault zone across the remainder of the quadrangle are significant areas and bands of hematite and iron-silicate mineral concentrations related to apparent alteration of iron sulfides.  The map defines the distribution of a variety of surficial deposits, including the distribution of hematite-rich colluvium and iron-silicate boulders.  The southeast

  6. Early Jurassic Volcanism in the South Lhasa Terrane, Southern Tibet: Record of Back-arc Extension in the Active Continental Margin

    Science.gov (United States)

    Wei, Y.; Zhao, Z.; Zhu, D. C.; Wang, Z.; Liu, D.; Mo, X.

    2015-12-01

    Indus-Yarlung Zangbo Suture Zone (IYZSZ) represents the Mesozoic remnants of the Neo-Tethyan Ocean lithosphere after its northward subduction beneath the Lhasa Terrane. The evolution of the Neo-Tethyan Ocean prior to India-Asia collision remains unclear. To explore this period of history, we investigate zircon U-Pb geochronology, geochemistry and Nd-Hf isotopes of the Early Jurassic bimodal-like volcanic sequence around Dagze area, south Tibet. The volcanic sequence comprises calc-alkaline basalts to rhyolites whereas intermediate components are volumetrically restricted. Zircons from a basaltic andesite yielded crystallization age of 178Ma whereas those from 5 silicic rocks were dated at 183-174Ma, which suggest that both the basaltic and the silicic rocks are coeval. The basaltic rocks are enriched in LREE and LILE, and depleted in HFSE, with Epsilon Nd(t) of 1.6-4.0 and zircon Epsilon Hf(t) of 0.7-11.8, which implies that they were derived from a heterogenetic mantle source metasomatized by subduction components. Trace element geochemistry shows that the basaltic rocks are compositionally transitional from normal mid-ocean ridge basalts (N-MORB) to island arc basalts (IAB, e.g. Zedong arc basalts of ~160-155Ma in the south margin of Lhasa Terrane), with the signature of immature back-arc basin basalts. The silicic rocks display similar Nd-Hf isotopic features of the Gangdese batholith with Epsilon Nd(t) of 0.9-3.4 and zircon Epsilon Hf(t) of 2.4-17.7, indicating that they were possibly generated by anatexis of basaltic juvenile lower crust, instead of derived from the basaltic magma. These results support an Early to Middle Jurassic (183-155Ma) model that the back-arc extension tectonic setting were existing in the active continental margin in the south Lhasa Terrane.

  7. Sedimentology of Hirnantian glaciomarine deposits in the Balkan Terrane, western Bulgaria: Fixing a piece of the north peri-Gondwana jigsaw puzzle

    Science.gov (United States)

    Chatalov, Athanas

    2017-04-01

    Glaciomarine deposits of late Hirnantian age in the western part of the Palaeozoic Balkan Terrane have persistent thickness ( 7 m) and lateral uniformity in rock colour, bedding pattern, lithology, and sedimentary structures. Four lithofacies are distinguished from base to top: lonestone-bearing diamictites, interbedded structureless mudstones, crudely laminated diamictites, and finely laminated mudstones. The diamictites are clast-poor to clast-rich comprising muddy to sandy varieties. Their compositional maturity is evidenced by the very high amount of detrital quartz compared to the paucity of feldspar and unstable lithic grains. Other textural components include extraclasts derived from the local Ordovician basement, mudstone intraclasts, and sediment aggregates. Turbate structures, grain lineations, and soft sediment deformation of the matrix below larger grains are locally observed. Sedimentological analysis reveals that deposition occurred in an ice-intermediate to ice-distal, poorly agitated shelf environment by material supplied from meltwater buoyant plumes and rain-out from ice-rafted debris. Remobilization by mass-flow processes (cohesive debris flows and slumps) was an important mechanism particularly for the formation of massive diamictites. The glaciomarine deposits represent a typical deglaciation sequence reflecting retreat of the ice front (grounded or floating ice sheet), relative sea-level rise and gradually reduced sedimentation rate with increasing contribution from suspension fallout. This sequence was deposited on the non-glaciated shelf of the intracratonic North Gondwana platform along the southern margin of the Rheic Ocean. The Hirnantian strata of the Balkan Terrane can be correlated with similar glaciomarine deposits known from peri-Gondwana terranes elsewhere in Europe showing clear 'Armorican affinity'. Several lines of evidence suggest that the provenance of siliciclastic material was associated mainly with sedimentary recycling of

  8. Late Triassic Porphyritic Intrusions And Associated Volcanic Rocks From The Shangri-La Region, Yidun Terrane, Eastern Tibetan Plateau: Implications For Adakitic Magmatism And Porphyry Copper Mineralization

    Science.gov (United States)

    Wang, B.; Zhou, M.; Li, J.; Yan, D.

    2011-12-01

    The Yidun terrane, located on the eastern margin of the Tibetan plateau, has been commonly considered to be a Triassic volcanic arc produced by subduction of the Ganzi-Litang oceanic lithosphere. The Yidun terrane is characterized by numerous arc-affinity granitic intrusions located along a 500-km-long, north-south-trending belt. Among these granitic bodies, several small porphyritic intrusions in the southern segment of the terrane (Shangri-La region) are associated with large porphyry copper deposits. These porphyritc intrusions are composed of diorite and quartz diorite, and spatially associated with andesites and dacites. LA-ICP-MS zircon U-Pb ages of the intrusions range from 230 to 215 Ma. The andesites and dacites are intercalated with slates and sandstones and have ages of around 220 Ma. The intrusive and volcanic rocks have SiO2 contents from 56.6 to 67.1 wt.%, Al2O3 from 14.2 to 17.4 wt.% and MgO from 1.9 to 4.2 wt.%. They show significant negative Nb-Ta anomalies on primitive mantle-normalized spidergrams. They have high La/Yb (13-49) ratios with no prominent Eu anomalies. All the rocks have high Sr (258-1980 ppm), and low Y (13-21 ppm) with high Sr/Y ratios (29-102). The geochemical features indicate that both the volcanic rocks and porphyritic intrusions were derived from adakitic magmas. They have similar initial 87Sr/86Sr ratios (0.7058 to 0.7077) and ɛNd (-1.88 to -4.93) values, but can be further divided into two groups: high silica (HSA) and low silica adakitic rocks (LSA). The HSA, representing an early stage of magmatism (230 to 215 Ma), were derived from oceanic slab melts with limited interaction with the overlying mantle wedge. At 215 Ma, more extensive interaction resulted in the formation of LSA. We propose that HSA were produced by flat subduction leading to melting of oceanic slab, whereas subsequent slab break-off caused the significant interaction between slab melts and the mantle wedge and thus the generation of the LSA. Compared with

  9. Draa Sfar, Morocco: A Visean (331 Ma) pyrrhotite-rich, polymetallic volcanogenic massive sulphide deposit in a Hercynian sediment-dominant terrane

    OpenAIRE

    Marcoux , Eric; Belkabir , Abdelhay; Gibson , Harold L.; Lentz , David; Ruffet , Gilles

    2008-01-01

    International audience; Draa Sfar is a Visean, stratabound, volcanogenic massive sulphide ore deposit hosted by a Hercynian carbonaceous, black shale-rich succession of the Jebilet terrane, Morocco. The ore deposit contains 10 Mt grading 5.3 wt.% Zn, 2 wt.% Pb, and 0.3 wt.% Cu within two main massive sulphides orebodies, Tazakourt (Zn-rich) and Sidi M'Barek (Zn–Cu rich). Pyrrhotite is by far the dominant sulphide (70 to 95% of total sulphides), sphalerite is fairly abundant, chalcopyrite and ...

  10. Mineral chemical and petrographic occurrences os iron of the south east of Uruguay (Nico Pere z terrane)

    International Nuclear Information System (INIS)

    Oyhantcabal, P.; Sanchez Bettucci, L.; Siegesmund, S.; Pineyro, D.

    2007-01-01

    Two iron-formation deposits from S E Uruguay were petrographic ally and mineralogically investigated (including microprobe mineral chemistry). The deposit from Piedra de Gigante (ANCAP) quarry is related to tectonic slivers of a platform succession in ortho gneiss of ca. 1750 Ma. Data of detrital zircon in this platform succession point to Meso- to Neo proterozoic age.The iron deposit of Piedra del Gigante (ANCAP) quarry belongs to a succession of mica schists, quartz-muscovite schists, marbles and basic rocks. Magnetite rich layers alternate with banded rocks rich in hematite, carbonate and amphibole. Carbonate is dolomite (Mg0.7Ca1.08Mn0.05Fe0.11(CO3)2) and the amphibole is a pale green tremolite (Na0,18Ca1,68Mn0,07Mg4,16Fe+++0,2Fe++0,55Al0,03(Si7,86Al0,13)O22(OH)2). This iron deposit shows strong deformation associated with martitization of magnetite and formation of specularite rich layers where relicts of magnetite (partly martitized) are occasionally observed. Available data are not conclusive about the genesis. The low iron-content of the amphibole together with dolomite in the mineral association cast doubts on a BIF-type origin, but low contents of Al2O3, V2O3, MnO and ZnO in magnetite do not indicate an igneous origin. High oxygen fugacity during martitization in medium-T metamorphic conditions could have determined that iron rich amphiboles were not formed as is normally expected in iron-formations. In the outcrop of Cerro la Higuerita (Grupo Arroyo del Soldado; Ediacaran) a succession of metapelites (bottom), iron rich pelites and iron formations (top) is observed. The metapelites contain evidences of volcanic contribution (phenochrysts of quartz and alkali feldspar as well as shards in the matrix) suggesting a volcanic source for the iron. This iron-formation contains magnetite pheno blasts (partly martitized) and fine disseminated laths of hematite in the matrix, together with grunerite (Na0,04Ca0,17 Mn0,02Mg1,36Fe5,35Al0,07(Si7,97Al0,03)O22(OH)2

  11. Adjacent segment disease and C-ADR: promises fulfilled?

    Science.gov (United States)

    Riew, K Daniel; Schenk-Kisser, Jeannette M.; Skelly, Andrea C.

    2012-01-01

    Study design: Systematic review. Clinical question: Do the rates and timing of adjacent segment disease (ASD) differ between cervical total disc arthroplasty (C-ADR) and anterior cervical discectomy and fusion (ACDF) in patients treated for cervical degenerative disc disease? Methods: A systematic search of MEDLINE/PubMed and bibliographies of key articles was done to identify studies with long-term follow-up for symptomatic and/or radiographic ASD comparing C-ADR with fusion for degenerative disc disease of the cervical spine. The focus was on studies with longer follow-up (48–60 months) of primary US Food and Drug Administration trials of Prestige ST, Prodisc-C, and Bryan devices as available. Trials of other discs with a minimum of 24 months follow-up were considered for inclusion. Studies evaluating lordosis/angle changes at adjacent segments and case series were excluded. Results: From 14 citations identified, four reports from three randomized controlled trials and four nonrandomized studies are summarized. Risk differences between C-ADR and ACF for symptomatic ASD were 1.5%–2.3% and were not significant across RCT reports. Time to development of ASD did not significantly differ between treatments. Rates of radiographic ASD were variable. No meaningful comparison of ASD rates based on disc design was possible. No statistical differences in adjacent segment range of motion were noted between treatment groups. Conclusion: Our analysis reveals that, to date, there is no evidence that arthroplasty decreases ASD compared with ACDF; the promise of arthroplasty decreasing ASD has not been fulfilled. PMID:23236312

  12. Microwave treatment of renal cell carcinoma adjacent to renal sinus.

    Science.gov (United States)

    Gao, Yongyan; Liang, Ping; Yu, Xiaoling; Yu, Jie; Cheng, Zhigang; Han, Zhiyu; Duan, Shaobo; Huang, Hui

    2016-11-01

    To evaluate the efficacy and safety of ultrasound (US)-guided percutaneous microwave ablation (MWA) for renal cell carcinoma (RCC) adjacent to renal sinus. This retrospective study included 41 patients who underwent US-guided percutaneous MWA of 41 RCCs adjacent to the renal sinus from April 2006 to December 2015. Contrast-enhanced images of US and computed tomography (CT) or magnetic resonance (MR) imaging were performed at pre-ablation and 1day, 1 month, 3 months, and every 6 months after ablation. Initial ablation success (IAS), disease-free survival (DFS), RCC-related survival (RRS), and overall survival (OS) were recorded at the follow-up visits. IAS was achieved in 92.7% (38/41) of the study subjects. The IAS significantly differed between patients with RCCs ≤4cm (100%, 29/29) and RCCs >4cm (75%, 9/12, p=0.021). During the median follow-up of 37.6 (range, 3.0-97.3) months, the estimated 1-, 3-, and 5-year DFS of patients with an initial tumor of ≤4cm were 100%, 89.7%, and 81.5%, respectively. The 1-, 3-, and 5-year RRS were 100%, 93.3%, and 93.3%, respectively. The 1-, 3-, and 5-year OS were 97.1%, 87.8%, and 83.6%, respectively. The multivariate analysis using the Cox proportional hazard model revealed no independent predictor of recurrence among all the variables. There were no MWA-related deaths among the study subjects. One patient developed a retroperitoneal abscess after ablation. US-guided percutaneous MWA appears to be a promising method for RCCs adjacent to renal sinus, especially for tumors ≤4cm. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. Cystic adventitial degeneration: ectopic ganglia from adjacent joint capsules.

    Science.gov (United States)

    Ortmann, J; Widmer, M K; Gretener, S; Do, D D; Willenberg, T; Daliri, A; Baumgartner, I

    2009-11-01

    Cystic adventitial degeneration is a rare non-atherosclerotic cause of peripheral arterial occlusive disease, mainly seen in young men without other evidence of vascular disease. Diagnosis will be established by clinical findings and by ultrasound or angiography and can be treated by excision or enucleation of the affected arterial segment or by percutaneous ultrasound-guided aspiration. However, the etiology of adventitial cysts remains unknown. We report a case of cystic adventitial degeneration showing a connection between the joint capsule and the adventitial cyst, supporting the theory that cystic adventitial degeneration may represent ectopic ganglia from adjacent joint capsules.

  14. Adjacent Lumbar Disc Herniation after Lumbar Short Spinal Fusion

    OpenAIRE

    Ninomiya, Koshi; Iwatsuki, Koichi; Ohnishi, Yu-ichiro; Ohkawa, Toshika; Yoshimine, Toshiki

    2014-01-01

    A 70-year-old outpatient presented with a chief complaint of sudden left leg motor weakness and sensory disturbance. He had undergone L4/5 posterior interbody fusion with L3–5 posterior fusions for spondylolisthesis 3 years prior, and the screws were removed 1 year later. He has been followed up for 3 years, and there had been no adjacent segment problems before this presentation. Lumbar magnetic resonance imaging (MRI) showed a large L2/3 disc hernia descending to the L3/4 level. Compared to...

  15. Osteoid Osteoma of Cervical Spine in two adjacent Vertebrae

    Directory of Open Access Journals (Sweden)

    MR Etemadifar

    2005-09-01

    Full Text Available Osteoid osteoma is a benign bone tumor, mainly seen in 10-30 years male. Spine is a relatively common site and almost always, posterior elements are involved. Plain X-Ray-, CT scan and Isotope scan help to identify and localize spine lesions. We described one 18 years old boy with 3 years low neck pain. Isotope scan, MRI and CT scan showed two lesions in C7 and T1. Gross inspection and histopathology examination confirmed osteoid osteoma in two adjacent vertebrae which has not been reported elsewhere in the literature. Key words: Osteoid Osteoma, Spine, Multifocal

  16. Microwave treatment of renal cell carcinoma adjacent to renal sinus

    International Nuclear Information System (INIS)

    Gao, Yongyan; Liang, Ping; Yu, Xiaoling; Yu, Jie; Cheng, Zhigang; Han, Zhiyu; Duan, Shaobo; Huang, Hui

    2016-01-01

    Highlights: • This study shows US-guided microwave ablation appears to be a promising method to treat renal cell carcinoma adjacent to renal sinus. • The estimated 1-, 3- and 5-year RCC-related survival were 100%, 93.3% and 93.3%, respectively. • The estimated 1-, 3- and 5-year overall survival were 97.1%, 87.8%, 83.6%, respectively. • For patients with RCC ≤4 cm, initial ablation success was 100% (29/29) and the estimated 5-year disease-free survival were 81.5%. - Abstract: Purpose: To evaluate the efficacy and safety of ultrasound (US)-guided percutaneous microwave ablation (MWA) for renal cell carcinoma (RCC) adjacent to renal sinus. Materials and methods: This retrospective study included 41 patients who underwent US-guided percutaneous MWA of 41 RCCs adjacent to the renal sinus from April 2006 to December 2015. Contrast-enhanced images of US and computed tomography (CT) or magnetic resonance (MR) imaging were performed at pre-ablation and 1 day, 1 month, 3 months, and every 6 months after ablation. Initial ablation success (IAS), disease-free survival (DFS), RCC-related survival (RRS), and overall survival (OS) were recorded at the follow-up visits. Results: IAS was achieved in 92.7% (38/41) of the study subjects. The IAS significantly differed between patients with RCCs ≤4 cm (100%, 29/29) and RCCs >4 cm (75%, 9/12, p = 0.021). During the median follow-up of 37.6 (range, 3.0–97.3) months, the estimated 1-, 3-, and 5-year DFS of patients with an initial tumor of ≤4 cm were 100%, 89.7%, and 81.5%, respectively. The 1-, 3-, and 5-year RRS were 100%, 93.3%, and 93.3%, respectively. The 1-, 3-, and 5-year OS were 97.1%, 87.8%, and 83.6%, respectively. The multivariate analysis using the Cox proportional hazard model revealed no independent predictor of recurrence among all the variables. There were no MWA-related deaths among the study subjects. One patient developed a retroperitoneal abscess after ablation. Conclusion: US-guided percutaneous MWA

  17. Microwave treatment of renal cell carcinoma adjacent to renal sinus

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Yongyan, E-mail: gaoyongyan7@163.com [Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 (China); Department of Ultrasound, The General Hospital of Chinese People’s Armed Police Forces, 69 Yongding Road, Beijing, 100039 (China); Liang, Ping, E-mail: liangping301@hotmail.com [Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 (China); Yu, Xiaoling, E-mail: 784107477@qq.com [Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 (China); Yu, Jie, E-mail: 1411495161@qq.com [Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 (China); Cheng, Zhigang, E-mail: 13691367317@163.com [Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 (China); Han, Zhiyu, E-mail: hanzhiyu122@163.com [Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 (China); Duan, Shaobo, E-mail: Dustin2662@163.com [Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 (China); Huang, Hui, E-mail: 309hh@sina.com [Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 (China)

    2016-11-15

    Highlights: • This study shows US-guided microwave ablation appears to be a promising method to treat renal cell carcinoma adjacent to renal sinus. • The estimated 1-, 3- and 5-year RCC-related survival were 100%, 93.3% and 93.3%, respectively. • The estimated 1-, 3- and 5-year overall survival were 97.1%, 87.8%, 83.6%, respectively. • For patients with RCC ≤4 cm, initial ablation success was 100% (29/29) and the estimated 5-year disease-free survival were 81.5%. - Abstract: Purpose: To evaluate the efficacy and safety of ultrasound (US)-guided percutaneous microwave ablation (MWA) for renal cell carcinoma (RCC) adjacent to renal sinus. Materials and methods: This retrospective study included 41 patients who underwent US-guided percutaneous MWA of 41 RCCs adjacent to the renal sinus from April 2006 to December 2015. Contrast-enhanced images of US and computed tomography (CT) or magnetic resonance (MR) imaging were performed at pre-ablation and 1 day, 1 month, 3 months, and every 6 months after ablation. Initial ablation success (IAS), disease-free survival (DFS), RCC-related survival (RRS), and overall survival (OS) were recorded at the follow-up visits. Results: IAS was achieved in 92.7% (38/41) of the study subjects. The IAS significantly differed between patients with RCCs ≤4 cm (100%, 29/29) and RCCs >4 cm (75%, 9/12, p = 0.021). During the median follow-up of 37.6 (range, 3.0–97.3) months, the estimated 1-, 3-, and 5-year DFS of patients with an initial tumor of ≤4 cm were 100%, 89.7%, and 81.5%, respectively. The 1-, 3-, and 5-year RRS were 100%, 93.3%, and 93.3%, respectively. The 1-, 3-, and 5-year OS were 97.1%, 87.8%, and 83.6%, respectively. The multivariate analysis using the Cox proportional hazard model revealed no independent predictor of recurrence among all the variables. There were no MWA-related deaths among the study subjects. One patient developed a retroperitoneal abscess after ablation. Conclusion: US-guided percutaneous MWA

  18. Age/isotopic characterisation of the Waipapa Group in Northland and Auckland, New Zealand, and implications for the status of the Waipapa Terrane

    International Nuclear Information System (INIS)

    Adams, C.J.; Maas, R.

    2004-01-01

    Rb-Sr ages of low-grade metasediments of the Waipapa Group (probable Permian-Jurassic) of Northland and Auckland range from Late Triassic (c. 209-217 Ma) to Middle Jurassic (c. 164-174 Ma), reflecting deformation and metamorphism during the Rangitata Orogeny. K-Ar ages indicate Middle Jurassic (c. 165-175 Ma) uplift and cooling of the western Omahuta-Puketi Forest block, and later, Middle-Late Jurassic (c. 150-160 Ma) cooling of the Helena Bay to Hunua Ranges eastern coastal block. In the intervening Western Bay of Islands block, there is evidence of local Early Cretaceous (c. 135 Ma) metamorphism. Rb-Sr whole-rock isochron age (t) and initial 87 Sr/ 86 Sr ratio (i) data support the assignment of Waipapa Group of the westernmost, Omahuta-Puketi block to the Caples Terrane. The remaining data have a consistent (t)-(i) signature, with (i) values 0.7039-0.7049, unlike Permian-Cretaceous Torlesse Supergroup metasediments with more radiogenic (i) values, typically >0.7060. They thus support the retention of a separate, Waipapa Terrane which continues southwards through central North Island to the Kaimanawa Ranges, and probably to Kapiti Island, and schist equivalents in eastern Marlborough. (author). 62 refs., 5 figs., 3 tabs

  19. Circum-Pacific accretion of oceanic terranes to continental blocks: accretion of the Early Permian Dun Mountain ophiolite to the E Gondwana continental margin, South Island, New Zealand

    Science.gov (United States)

    Robertson, Alastair

    2016-04-01

    Accretionary orogens, in part, grow as a result of the accretion of oceanic terranes to pre-existing continental blocks, as in the circum-Pacific and central Asian regions. However, the accretionary processes involved remain poorly understood. Here, we consider settings in which oceanic crust formed in a supra-subduction zone setting and later accreted to continental terranes (some, themselves of accretionary origin). Good examples include some Late Cretaceous ophiolites in SE Turkey, the Jurassic Coast Range ophiolite, W USA and the Early Permian Dun Mountain ophiolite of South Island, New Zealand. In the last two cases, the ophiolites are depositionally overlain by coarse clastic sedimentary rocks (e.g. Permian Upukerora Formation of South Island, NZ) that then pass upwards into very thick continental margin fore-arc basin sequences (Great Valley sequence, California; Matai sequence, South Island, NZ). Field observations, together with petrographical and geochemical studies in South Island, NZ, summarised here, provide evidence of terrane accretion processes. In a proposed tectonic model, the Early Permian Dun Mountain ophiolite was created by supra-subduction zone spreading above a W-dipping subduction zone (comparable to the present-day Izu-Bonin arc and fore arc, W Pacific). The SSZ oceanic crust in the New Zealand example is inferred to have included an intra-oceanic magmatic arc, which is no longer exposed (other than within a melange unit in Southland), but which is documented by petrographic and geochemical evidence. An additional subduction zone is likely to have dipped westwards beneath the E Gondwana margin during the Permian. As a result, relatively buoyant Early Permian supra-subduction zone oceanic crust was able to dock with the E Gondwana continental margin, terminating intra-oceanic subduction (although the exact timing is debatable). The amalgamation ('soft collision') was accompanied by crustal extension of the newly accreted oceanic slab, and

  20. Triassic arc-derived detritus in the Triassic Karakaya accretionary complex was not derived from either the S Eurasian margin (Istanbul terrane) or the N Gondwana margin (Taurides)

    Science.gov (United States)

    Ustaömer, Timur; Ayda Ustaömer, Petek; Robertson, Alastair H. F.; Gerdes, Axel; Zulauf, Gernold

    2014-05-01

    We present new U-Pb zircon source age data for Upper Triassic sandstones of the Istanbul Terrane (S Eurasian margin) and also for Triassic sandstones of the Taurides (N Gondwana margin). The main aim is to detect and quantify the contribution of Triassic magmatism as detritus to either of these crustal blocks. This follows the recent discovery of a Triassic magmatic arc source for the Triassic sandstones of the Palaeotethyan Karakaya subduction-accretion complex (Ustaömer et al. 2013; this meeting). Carboniferous (Variscan) zircon grains also form a significant detrital population, plus several more minor populations. Six sandstone samples were studied, two from the İstanbul Terrane (Bakırlıkıran Formation of the Kocaeli Triassic Basin) and four from the Tauride Autochthon (latest Triassic Üzümdere Formation and Mid-Triassic Kasımlar Formations; Beyşehir region). Detrital zircon grains were dated by the laser ablation-inductively coupled plasma-mass spectrometer (LA-ICP-MS) U-Pb method at Goethe University, Frankfurt. Our results do not reveal Triassic detritus in the Üzümdere Formation. The U-Pb age of the analysed zircon grains ranges from 267 Ma to 3.2 Ga. A small fraction of Palaeozoic zircons are Permian (267 to 296 Ma), whereas the remainder are Early Palaeozoic. Ordovician grains (4%) form two age clusters, one at ca. 450 Ma and the other at ca. 474 Ma. Cambrian-aged grains dominate the zircon population, while the second largest population is Ediacaran (576 to 642 Ma). Smaller populations occur at 909-997 Ma, 827-839 Ma, 1.8-2.0 Ga and 2.4-2.6 Ga. The sandstones of the Kasımlar Formation have similar zircon age cluster to those of the somewhat younger Üzümdere Formation, ranging from 239 Ma to 2.9 Ga. A few grains gave Anisian ages. Cambrian zircon grains are less pronounced than in the Kasımlar Formation compared to the Üzümdere Formation. The detrital zircon record of Tauride sandstones, therefore, not indicates significant contribution

  1. Adjacent segment disease in degenerative pathologies with posterior instrumentation

    Directory of Open Access Journals (Sweden)

    Ana Guadalupe Ramírez Olvera

    2015-03-01

    Full Text Available OBJECTIVE: To establish the real incidence of adjacent segment disease after fusion, and to identify the levels and predisposing factors for the pathology, as well as the functional results. METHODS: a retrospective case series study with level of evidence IIB, in a sample of 179 patients diagnosed with stenosis of the lumbar spine, spondylolisthesis and degenerative scoliosis, submitted to surgery in the period 2005 to December 2013, with posterior instrumentation and posterolateral fusion, with follow-up from 2007 until May 2014, in which the symptomology and radiographic findings were evaluated, to establish the diagnosis and treatment. RESULTS: the study included 179 patients diagnosed with stenosis of the lumbar spine (n=116, isthmic and degenerative spondylolisthesis (n=50 and degenerative scoliosis (n=13; during the study, 20 cases of adjacent level segment were identified, 80% of which were treated surgically with extension of the instrumentation, while 20% were treated conservatively with NSAIDs and therapeutic blocks. CONCLUSION: An incidence of 11% was found, with an average of 3.25 years in diagnosis and treatment, a prevalence of females and diagnosis of stenosis of the lumbar canal on posterior instrumentation, a predominance of levels L4-L5; 80% were treated with extension of the instrumentation. The complications were persistent radiculopathy, infection of the surgical wound, and one death due to causes not related to the lumbar pathology.

  2. ORNAMENTAL PLANTS OF CHECHNYA AND ITS ADJACENT AREAS

    Directory of Open Access Journals (Sweden)

    Musa A. Taysumov

    2018-01-01

    Full Text Available Abstract. The aim of the research is to summarize the scattered information about the types of decorative flora of the Chechen Republic and adjacent territories; to identify highly resistant ornamental plants for cities and settlements of the North Caucasus and other territories of Russia. Discussion. Currently, in a variety of botanical gardens of the North Caucasus grows a large number of decorative plant species, widely used in green construction. However, not all species posses the quality to sufficient resist unfavorable conditions of the changed abiotic and biotic environment. Among the studied, the most valuable and promising for widespread introduction are the species of more than 122 taxa, the decorative effect of which is preserved throughout the year with no signs of aging. Many examples of the targeted use of herbs, tree species, lianas, bulbous plants were cited in the research. We give a large list of Caucasian species for growing on lawns, flowerbeds, flower gardens, alpine and stony mountains, roadsides and parks, urban parks, squares and alleys as a type of gardening. Their decorative properties, vitality, durability, life form and other bio-ecological features, attitude to abiotic factors (soil conditions, illumination, temperature, soil and atmospheric humidification conditions, etc. were taken into account. Conclusion. We give a large list of ornamental species and various planting techniques of specific species are introduced in conditions of Chechnya and its adjacent territories as well as the methods of implementing in the landscaping practice in other (middle and northern regions of Russia.

  3. Absorbed dose distribution analyses in irradiation with adjacent fields

    International Nuclear Information System (INIS)

    Cudalbu, C.; Onuc, C.; Andrada, S.

    2002-01-01

    Because the special irradiation technique with adjacent fields is the most used in the case of medulloblastoma treatment, we consider very important to specify some general information about medulloblastoma. This malignant disease has a large incidence in children with age between 5-7 years. This tumor usually originates in the cerebellum and is referred to as primitive undifferentiated tumor. It may spread contiguously to the cerebellar peduncle, floor of the fourth ventricle, into the cervical spine. In addition, it may spread via the cerebrospinal fluid intracranially and/or to the spinal cord. For this purpose it is necessary to perform a treatment technique with cranial tangential fields combined with adjacent fields for the entire spinal cord to achieve a perfect coverage of the zones with malignant cells. The treatment in this case is an association between surgery-radio-chemotherapy, where the radiotherapy has a very important roll and a curative purpose. This is due to the fact that the migration of malignant cells in the body can't be controlled by surgery. Because of this special irradiation technique used in medulloblastoma treatment, we chase to describe in this paper this complex type of irradiation where the implications of the beams divergence in doses distribution are essentials

  4. Calculations of the electrostatic potential adjacent to model phospholipid bilayers.

    Science.gov (United States)

    Peitzsch, R M; Eisenberg, M; Sharp, K A; McLaughlin, S

    1995-03-01

    We used the nonlinear Poisson-Boltzmann equation to calculate electrostatic potentials in the aqueous phase adjacent to model phospholipid bilayers containing mixtures of zwitterionic lipids (phosphatidylcholine) and acidic lipids (phosphatidylserine or phosphatidylglycerol). The aqueous phase (relative permittivity, epsilon r = 80) contains 0.1 M monovalent salt. When the bilayers contain equipotential surfaces are discrete domes centered over the negatively charged lipids and are approximately twice the value calculated using Debye-Hückel theory. When the bilayers contain > 25% acidic lipid, the -25 mV equipotential profiles are essentially flat and agree well with the values calculated using Gouy-Chapman theory. When the bilayers contain 100% acidic lipid, all of the equipotential surfaces are flat and agree with Gouy-Chapman predictions (including the -100 mV surface, which is located only 1 A from the outermost atoms). Even our model bilayers are not simple systems: the charge on each lipid is distributed over several atoms, these partial charges are non-coplanar, there is a 2 A ion-exclusion region (epsilon r = 80) adjacent to the polar headgroups, and the molecular surface is rough. We investigated the effect of these four factors using smooth (or bumpy) epsilon r = 2 slabs with embedded point charges: these factors had only minor effects on the potential in the aqueous phase.

  5. UNITED STATES DEPARTMENT OF TRANSPORTATION GLOBAL POSITIONING SYSTEM (GPS) ADJACENT BAND COMPATIBILITY ASSESSMENT

    Science.gov (United States)

    2018-04-01

    The goal of the U.S. Department of Transportation (DOT) Global Positioning System (GPS) Adjacent Band Compatibility Assessment is to evaluate the maximum transmitted power levels of adjacent band radiofrequency (RF) systems that can be tolerated by G...

  6. Uncertainty in 14C model ages of groundwater: The influence of soil gas in terranes dominated by C3 plants

    Science.gov (United States)

    Nelson, S.; Hart, R.; Eggett, D.

    2009-12-01

    Groundwater is the largest source of fresh water readily available to humanity and aquifers with long residence times are particularly susceptible to overuse. Thus, it is important to have quantitative estimates of the residence time of water in such aquifers. Many models used to calculate 14C ages of groundwater depend on an estimate of the δ13C value of carbon dioxide in soil at the time of recharge, a value that must be estimated. Other work has suggested that for terranes dominated by C3 plants, -23‰ is an appropriate value, and sensitivity calculations show that the apparent age of a groundwater is strongly dependent on the choice of this parameter. This is especially true where the measured values of δ13C of dissolved inorganic carbon (DIC) are used to estimate the contribution of “dead” carbon to the DIC load via the dissolution of calcite in the aquifer and soil zones. To better understand the temporal and spatial isotopic and abundance variability of soil carbon dioxide, we established soil gas sampling sites that encompassed a wide variety of settings in terms of season, elevation, climate, and plant community that were sampled monthly throughout regions of the state of Utah where C3 flora dominate. Direct measurements of soil gas suggest a value of -21.8 ± 1.4‰ (1σ) is a good input variable as long as: a) C3 vegetation dominates, and b) extreme aridity does not prevail such that plant densities and soil microbial activities are minimized. If recharge is envisaged to occur during spring and early summer in highly vegetated uplands, a value of -24.0 ± 0.6‰ may be more appropriate as statistical analysis reveals that seasonality and plant density are most clearly correlated to the carbon isotope composition of carbon dioxide in soil gas. Although the two values and ranges cited above values do not diverge strongly from other published estimates, they place fairly narrow limits on the uncertainty of ±500 and ±200 yr., respectively, in

  7. Tritium in the Savannah River Estuary and adjacent marine waters

    International Nuclear Information System (INIS)

    Hayes, D.W.

    1978-01-01

    The tritium distribution in the Savannah River estuary and adjacent marine waters was measured to provide information on the dilution, mixing, and movement of Savannah River water in this region. The Savannah River marine region was chosen because the average tritium concentration in this river is 5 pCi/ml, whereas other rivers in the southeastern United States average less than 0.5 pCi/ml. The increased tritium concentration in the Savannah River is due to releases from the Savannah River Plant of the Department of Energy. Tritium measurements have proved particularly effective in estimating the flushing time of the Savannah River estuary (2.4 days) and in delineating the relative contribution to the water masses in Ossabaw and Port Royal Sounds from the River and from sea water. Ossabaw and Port Royal Sounds are located approximately 20 km south and north of the Savannah River estuary, respectively

  8. Tritium in the Savannah River estuary and adjacent marine waters

    International Nuclear Information System (INIS)

    Hayes, D.W.

    1979-01-01

    The tritium distribution in the Savannah River estuary and adjacent marine waters was measured to provide information on the dilution, mixing and movement of Savannah River water in this region. The Savannah River marine region was chosen because the average tritium concentration in this river is approximately 5 pCi/ml, whereas other rivers in the southeastern United States of America average less than 0.5 pCi/ml. The increased tritium concentration in the Savannah River is due to releases from the Savannah River Plant of the Department of Energy. Tritium measurements have proved particularly effective in estimating the flushing time of the Savannah River estuary (2.4 days) and in delineating the relative contribution to the water masses in Ossabaw and Port Royal Sounds from the river and from sea-water. Ossabaw and Port Royal Sounds are located approximately 20 km south and north of the Savannah River estuary respectively. (author)

  9. Adjacent Lumbar Disc Herniation after Lumbar Short Spinal Fusion

    Directory of Open Access Journals (Sweden)

    Koshi Ninomiya

    2014-01-01

    Full Text Available A 70-year-old outpatient presented with a chief complaint of sudden left leg motor weakness and sensory disturbance. He had undergone L4/5 posterior interbody fusion with L3–5 posterior fusions for spondylolisthesis 3 years prior, and the screws were removed 1 year later. He has been followed up for 3 years, and there had been no adjacent segment problems before this presentation. Lumbar magnetic resonance imaging (MRI showed a large L2/3 disc hernia descending to the L3/4 level. Compared to the initial MRI, this hernia occurred in an “intact” disc among multilevel severely degenerated discs. Right leg paresis and bladder dysfunction appeared a few days after admission. Microscopic lumbar disc herniotomy was performed. The right leg motor weakness improved just after the operation, but the moderate left leg motor weakness and difficulty in urination persisted.

  10. Edge scour in current adjacent to stone covers

    DEFF Research Database (Denmark)

    Petersen, Thor Ugelvig; Sumer, B. Mutlu; Meyer, Knud Erik

    The present paper reports some early results of an experimental investigation of edge scour in currents. Two kinds of measurements are made (1) Particle Image Velocimetry (PIV) measurements of secondary currents that take place near a junction between the stone cover and the sand bed in a clear......-water experiment; and (2) scour measurements in actual scour experiment in the live-bed regime. The early results indicate that edge scour in a steady current propagating in-line with a stone layer is caused by the combined action of two effects; (1) Primary flow and (2) Secondary flow. The primary flow stirs up...... the sediment and puts into suspension, and the secondary flow carries it away from the junction between the stone layer and the sand bed, resulting in a scour hole forming adjacent to the toe of the stone layer....

  11. GOAT ROCKS WILDERNESS AND ADJACENT ROADLESS AREAS, WASHINGTON.

    Science.gov (United States)

    Church, S.E.; Close, T.J.

    1984-01-01

    The Goat Rocks Wilderness and adjacent roadless areas are a rugged, highly forested, scenic area located on the crest of the Cascade Range in south-central Washington. Several mineral claims have been staked in the area. Mineral surveys were conducted. Geochemical, geophysical, and geologic investigations indicate that three areas have probable mineral-resource potential for base metals in porphyry-type deposits. Available data are not adequate to permit definition of the potential for oil and gas. There is little likelihood for the occurrence of other kinds of energy resources in the area. Evaluation of resource potential in the three areas identified as having probable mineral-resource potential could be improved by more detailed geochemical studies and geologic mapping.

  12. Adjacent segment infection after surgical treatment of spondylodiscitis.

    Science.gov (United States)

    Siam, Ahmed Ezzat; El Saghir, Hesham; Boehm, Heinrich

    2016-03-01

    This is the first case series to describe adjacent segment infection (ASI) after surgical treatment of spondylodiscitis (SD). Patients with SD, spondylitis who were surgically treated between 1994 and 2012 were included. Out of 1187 cases, 23 (1.94 %) returned to our institution (Zentralklinik Bad Berka) with ASI: 10 males, 13 females, with a mean age of 65.1 years and a mean follow-up of 69 months. ASI most commonly involved L3-4 (seven patients), T12-L1 (five) and L2-3 (four). The mean interval between operations of primary infection and ASI was 36.9 months. All cases needed surgical intervention, debridement, reconstruction and fusion with longer instrumentation, with culture and sensitivity-based postoperative antimicrobial therapy. At last follow-up, six patients (26.1 %) were mobilized in a wheelchair with a varying degree of paraplegia (three had pre-existing paralysis). Three patients died within 2 months after the ASI operation (13 %). Excellent outcomes were achieved in five patients, and good in eight. Adjacent segment infection after surgical treatment of spondylodiscitis is a rare complication (1.94 %). It is associated with multimorbidity and shows a high mortality rate and a high neurological affection rate. Possible explanations are: haematomas of repeated micro-fractures around screw loosening, haematogenous spread, direct inoculation or a combination of these factors. ASI may also lead to proximal junctional kyphosis, as found in this series. We suggest early surgical intervention with anterior debridement, reconstruction and fusion with posterior instrumentation, followed by antimicrobial therapy for 12 weeks. Level IV retrospective uncontrolled case series.

  13. Shaping the Australian crust over the last 300 million years: insights from fission track thermotectonic imaging and denudation studies of key terranes

    International Nuclear Information System (INIS)

    Kohn, B.P.; Gleadow, A.J.W.; Brown, R.W.; O'Sullivan, P.B.; Foster, D.A.; Gallagher, K.

    2002-01-01

    Apatite fission track thermochronology is a well-established tool for reconstructing the low-temperature thermal and tectonic evolution of continental crust. The variation of fission track ages and distribution of fission track lengths are primarily controlled by cooling, which may be initiated by earth movements and consequent denudation at the Earth's surface and/or by changes in the thermal regime. Using numerical forward-modelling procedures these parameters can be matched with time-temperature paths that enable thermal and tectonic processes to be mapped out in considerable detail. This study describes extensive Australian regional fission track datasets that have been modelled sequentially and inverted into time-temperature solutions for visualisation as a series of time-slice images depicting the cooling history of present-day surface rocks during their passage through the upper crust. The data have also been combined with other datasets, including digital elevation and heat flow, to image the denudation history and the evolution of palaeo-topography. These images provide an important new perspective on crustal processes and landscape evolution and show how important tectonic and denudation events over the last 300 million years can be visualised in time and space. The application of spatially integrated denudation-rate chronology is also demonstrated for some key Australian terranes including the Lachlan and southern New England Orogens of southeastern Australia, Tasmania, the Gawler Craton, the Mt lsa lnlier, southwestern Australian crystalline terranes (including the Yilgarn Craton) and the Kimberley Block. This approach provides a readily accessible framework for quantifying the otherwise undetectable, timing and magnitude of long-term crustal denudation in these terranes, for a part of the geological record previously largely unconstrained. Discrete episodes of enhanced denudation occurred principally in response to changes in drainage, base

  14. Map Showing Geologic Terranes of the Hailey 1°x2° Quadrangle and the western part of the Idaho Falls 1°x2° Quadrangle, south-central Idaho

    Data.gov (United States)

    Department of the Interior — The paper version of Map Showing Geologic Terranes of the Hailey 1°x2° Quadrangle and the western part of the Idaho Falls 1°x2° Quadrangle, south-central Idaho was...

  15. Characterisation and monitoring of the Excavation Disturbed Zone (EDZ) in fractured gneisses of the Roselend underground laboratory: permeability measurements, transport property changes and related radon bursts

    Science.gov (United States)

    Wassermann, Jérôme; Sabroux, Jean-Christophe; Richon, Patrick; Pontreau, Sébastien; Guillon, Sophie; Pili, Eric

    2010-05-01

    The Roselend tunnel was drilled in the fifties by blasting in the micashists, granites and gneisses of the Méraillet massif (French Alps). It is situated on the shore of the Roselend reservoir Lake near its dam. Several tectonic shear fractures related to the Alpine orogeny intersect the dead end tunnel (with length of 128 m and section about 2 m), indeed the fracture density varies from 0.45 to 1 fracture per meter along the tunnel (Dezayes and Villemin 2002). Some fractures are partially or totally filled with secondary minerals. The flow rates of percolating water through the fractured medium are seasonal dependent. Large fractures drain a large fluid volume unlike small ones that drain limited fluid volume (Patriarche et al. 2007). The Roselend underground laboratory allows the study of the geochemical and geophysical responses of a fractured rock mass to periodic sollicitations due to water level variations of the nearby Roselend reservoir Lake. The tunnel was instrumented in the nineties to understand the relationship between radon (Rn-222) concentration and water level variations of the Roselend reservoir Lake (Trique et al. 1999). In order to characterize the geometry and the extent of the EDZ, core drilling and permeability measurements through pneumatic testing are performed along the Roselend tunnel. Drilled core analysis consists of direct observations at a macroscopic scale of fractures (density of fractures from EDZ) and also at a microscopic scale via thin sections. Method of pressure build-up in wells (Jakubick and Franz 1993, Bossart et al. 2002) is used to determine permeability profile along each borehole and hence to precise the extent and geometry of the EDZ. A strong correlation is observed between permeability profiles and the density of fractures estimated from core analysis. The extent of the EDZ appears to be about one tunnel radius i.e. one meter around the tunnel corridor. Another experiment consisting of continuous differential

  16. On Mathematical Optimization for the Visualization of Frequencies and Adjacencies as Rectangular Maps

    DEFF Research Database (Denmark)

    Carrizosa, Emilio; Guerrero, Vanesa; Morales, Dolores Romero

    2018-01-01

    individuals as adjacent rectangular portions as possible and adding as few false adjacencies, i.e., adjacencies between rectangular portions corresponding to non-adjacent individuals, as possible. We formulate this visualization problem as a Mixed Integer Linear Programming (MILP) model. We propose......In this paper we address the problem of visualizing a frequency distribution and an adjacency relation attached to a set of individuals. We represent this information using a rectangular map, i.e., a subdivision of a rectangle into rectangular portions so that each portion is associated with one...

  17. Mantle accretion evidence during the neoproterozoic of the Pernambuco-Alagoas terrane, and its significance to the evolution of the Borborema Province, NE Brazil

    International Nuclear Information System (INIS)

    Silva Filho, A.F.; Guimaraes, I.P; Van Schmus, W.R

    2001-01-01

    The Borborema Province is located in NE Brazil, corresponding to the western part of a major fold belt, which extends from Brazil to West Africa. According to paleogeographic reconstruction, it is located between the Congo, Sao Francisco and West Africa cratons. The Pernambuco-Alagoas Terrane is a major tectonic unit of the Borborema Province and comprises high-grade metamorphic sequences and the greatest granitic batholiths of this province. The granitic batholiths Maribondo-Correntes, Buique-Paulo Afonso and Aguas Belas-Caninde and their ortho derived country rocks show metaluminous and peraluminous compositions, and εNd(0,60 Ga) between +3,2 and -2,0 and T DM between 0,90 Ga and 1,20 Ga. These Nd isotope data favour a crustal evolution hypothesis involving accretion of juvenile material at least during the Brasiliano orogenesis collision and perhaps the formation of a juvenile lithosphere during the end of the Mesoproterozoic (au)

  18. Regional framework and geology of iron oxide-apatite-rare earth element and iron oxide-copper-gold deposits of the Mesoproterozoic St. Francois Mountains Terrane, southeast Missouri

    Science.gov (United States)

    Day, Warren C.; Slack, John F.; Ayuso, Robert A.; Seeger, Cheryl M.

    2016-01-01

    This paper provides an overview on the genesis of Mesoproterozoic igneous rocks and associated iron oxide ± apatite (IOA) ± rare earth element, iron oxide-copper-gold (IOCG), and iron-rich sedimentary deposits in the St. Francois Mountains terrane of southeast Missouri, USA. The St. Francois Mountains terrane lies along the southeastern margin of Laurentia as part of the eastern granite-rhyolite province. The province formed during two major pulses of igneous activity: (1) an older early Mesoproterozoic (ca. 1.50–1.44 Ga) episode of volcanism and granite plutonism, and (2) a younger middle Mesoproterozoic (ca. 1.33–1.30 Ga) episode of bimodal gabbro and granite plutonism. The volcanic rocks are predominantly high-silica rhyolite pyroclastic flows, volcanogenic breccias, and associated volcanogenic sediments with lesser amounts of basaltic to andesitic volcanic and associated subvolcanic intrusive rocks. The iron oxide deposits are all hosted in the early Mesoproterozoic volcanic and volcaniclastic sequences. Previous studies have characterized the St. Francois Mountains terrane as a classic, A-type within-plate granitic terrane. However, our new whole-rock geochemical data indicate that the felsic volcanic rocks are effusive derivatives from multicomponent source types, having compositional similarities to A-type within-plate granites as well as to S- and I-type granites generated in an arc setting. In addition, the volcanic-hosted IOA and IOCG deposits occur within bimodal volcanic sequences, some of which have volcanic arc geochemical affinities, suggesting an extensional tectonic setting during volcanism prior to emplacement of the ore-forming systems.The Missouri iron orebodies are magmatic-related hydrothermal deposits that, when considered in aggregate, display a vertical zonation from high-temperature, magmatic ± hydrothermal IOA deposits emplaced at moderate depths (~1–2 km), to magnetite-dominant IOA veins and IOCG deposits emplaced at shallow

  19. Advanced Land Observing Satellite (ALOS) Phased Array Type L-Band Synthetic Aperture Radar (PALSAR) mosaic for the Kahiltna terrane, Alaska, 2007-2010

    Science.gov (United States)

    Cole, Christopher J.; Johnson, Michaela R.; Graham, Garth E.

    2015-01-01

    The U.S. Geological Survey (USGS) has initiated a multi-disciplinary study investigating the applicability of remote sensing technologies for geologic mapping and identification of prospective areas for base and precious metal deposits in remote parts of Alaska. The Kahiltna terrane in southwestern Alaska was selected for investigation because of its known mineral deposits and potential for additional mineral resources. An assortment of technologies is being investigated to aid in remote analysis of terrain, and includes imaging spectroscopy (hyperspectral remote sensing), high spatial resolution electro-optical imagery, and Synthetic Aperture Radar (SAR). However, there are significant challenges to applying imaging spectroscopy and electro-optical imagery technologies in this area because of the low solar angle for parts of the year, seasonal periods of darkness and snow cover, and the frequently cloudy weather that characterizes Alaska. Synthetic Aperture Radar (SAR) was selected because this technology does not rely on solar illumination and has all-weather capability.

  20. Methodology for the systematic reviews on an adjacent segment pathology.

    Science.gov (United States)

    Norvell, Daniel C; Dettori, Joseph R; Skelly, Andrea C; Riew, K Daniel; Chapman, Jens R; Anderson, Paul A

    2012-10-15

    A systematic review. To provide a detailed description of the methods undertaken in the systematic search and analytical summary of adjacent segment pathology (ASP) issues and to describe the process used to develop consensus statements and clinical recommendations regarding factors associated with the prevention and treatment of ASP. We present methods used in conducting the systematic, evidence-based reviews and development of expert panel consensus statements and clinical recommendations on the classification, natural history, risk factors, and treatment of radiographical and clinical ASP. Our intent is that clinicians will combine the information from these reviews with an understanding of their own capacities and experience to better manage patients at risk of ASP and consider future research for the prevention and treatment of ASP. A systematic search and critical review of the English-language literature was undertaken for articles published on the classification, risk, risk factors, and treatment of radiographical and clinical ASP. Articles were screened for relevance using a priori criteria, and relevant articles were critically reviewed. Whether an article was included for review depended on whether the study question was descriptive, one of therapy, or one of prognosis. The strength of evidence for the overall body of literature in each topic area was determined by 2 independent reviewers considering risk of bias, consistency, directness, and precision of results using a modification of the Grades of Recommendation Assessment, Development and Evaluation (GRADE) criteria. Disagreements were resolved by consensus. Findings from articles meeting inclusion criteria were summarized. From these summaries, consensus statements or clinical recommendations were formulated among subject experts through a modified Delphi process using the GRADE approach. A total of 3382 articles were identified and screened on 14 topics relating to the classification, risks, risk

  1. An autochthonous Avalonian basement source for the latest Ordovician Brenton Pluton in the Meguma terrane of Nova Scotia: U-Pb-Hf isotopic constraints and paleogeographic implications

    Science.gov (United States)

    Duncan Keppie, J.; Gregory Shellnutt, J.; Dostal, Jaroslav; Fraser Keppie, D.

    2018-04-01

    The Ediacaran-Ordovician Meguma Supergroup was thrust over Avalonia basement prior to the intrusion of post-Acadian, ca. 370 Ma, S-type granitic batholiths. This has led to two main hypotheses regarding the original location of the Meguma terrane, a continental rise prism bordering either NW Africa or Avalonia. On the other hand, the pre-Acadian, ca. 440 Ma Brenton pluton has yielded the following U/Pb LA-ICP-MS zircon data: (1) 448 ± 3 Ma population peak inferred to be the intrusive age and (2) ca. 550 and 700 Ma inherited ages common to both Avalonia and NW Africa. In contrast, Hf isotopic analyses of zircon yielded model ages ranging from 814 to 1127 Ma with most between 940 and 1040 Ma: such ages are typical of Avalonia and not NW Africa. The ages of the inherited zircons found within the Brenton pluton suggest that it was probably derived by partial melting of sub-Meguma, mid-crustal Avalonian rocks, upon which the Meguma Supergroup was deposited. Although Avalonia is commonly included in the peri-Gondwanan terranes off NW Africa or Amazonia, paleomagnetic data, faunal provinciality, and Hf data suggest that, during the Ediacaran-Early Cambrian, it was an island chain lying near the tropics (ca. 20-30 °S) and was possibly a continuation of the Bolshezemel volcanic arc accreted to northern Baltica during the Ediacaran Timanide orogenesis. This is consistent with the similar derital zircon population in the Ediacaran-Cambrian Meguma Supergroup and the Dividal Group in northeastern Baltica.

  2. What was the Paleogene latitude of the Lhasa terrane? A reassessment of the geochronology and paleomagnetism of Linzizong volcanic rocks (Linzhou basin, Tibet)

    Science.gov (United States)

    Huang, Wentao; Dupont-Nivet, Guillaume; Lippert, Peter C.; van Hinsbergen, Douwe J. J.; Dekkers, Mark J.; Waldrip, Ross; Ganerød, Morgan; Li, Xiaochun; Guo, Zhaojie; Kapp, Paul

    2015-03-01

    The Paleogene latitude of the Lhasa terrane (southern Tibet) can constrain the age of the onset of the India-Asia collision. Estimates for this latitude, however, vary from 5°N to 30°N, and thus, here, we reassess the geochronology and paleomagnetism of Paleogene volcanic rocks from the Linzizong Group in the Linzhou basin. The lower and upper parts of the section previously yielded particularly conflicting ages and paleolatitudes. We report consistent 40Ar/39Ar and U-Pb zircon dates of 52 Ma for the upper Linzizong, and 40Ar/39Ar dates ( 51 Ma) from the lower Linzizong are significantly younger than U-Pb zircon dates (64-63 Ma), suggesting that the lower Linzizong was thermally and/or chemically reset. Paleomagnetic results from 24 sites in lower Linzizong confirm a low apparent paleolatitude of 5°N, compared to the upper part ( 20°N) and to underlying Cretaceous strata ( 20°N). Detailed rock magnetic analyses, end-member modeling of magnetic components, and petrography from the lower and upper Linzizong indicate widespread secondary hematite in the lower Linzizong, whereas hematite is rare in upper Linzizong. Volcanic rocks of the lower Linzizong have been hydrothermally chemically remagnetized, whereas the upper Linzizong retains a primary remanence. We suggest that remagnetization was induced by acquisition of chemical and thermoviscous remanent magnetizations such that the shallow inclinations are an artifact of a tilt correction applied to a secondary remanence in lower Linzizong. We estimate that the Paleogene latitude of Lhasa terrane was 20 ± 4°N, consistent with previous results suggesting that India-Asia collision likely took place by 52 Ma at 20°N.

  3. Petrogenesis, U-Pb and Sm-Nd geochronology of the Furna Azul Migmatite: partial melting evidence during the San Ignacio Orogeny, Paragua Terrane, SW Amazon Craton

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Newton Diego Couto do; Ruiz, Amarildo Salina; Pierosan, Ronaldo; Lima, Gabrielle Aparecida de; Matos, Joao Batista; Lafon, Jean-Michel; Moura, Candido Augusto Veloso, E-mail: newtongeologia@hotmail.com, E-mail: asruiz@gmail.com, E-mail: ronaldo.pierosan@yahoo.com.br, E-mail: gabilimagel@gmail.com, E-mail: lafonjm@ufpa.br, E-mail: prof.jmatos@gmail.com, E-mail: candido@ufpa.br [Universidade Federal do Para (GEOCIAM/UFPA), Belem, PA (Brazil). Instituto Nacional de Ciencia e Tecnologia de Geociencias da Amazonia

    2016-11-01

    The Furna Azul Migmatite is a ∼10 km{sup 2} complex located in Pontes e Lacerda city, Mato Grosso, Brazil. It belongs to Paragua Terrane, limit with Rio Alegre Terrane, southeast of San Ignacio Province, in Amazon Craton. It consists of transitional metatexites with amphibolite enclaves and dioritic injections. The rocks were divided in residuum rich and leucosome rich; both have three deformation phases marked by folded stromatic layers affected by spaced foliation and metamorphosed in amphibolite facies, represented by garnet, biotite, sillimanite, and by the clinopyroxene in the enclaves. The metamorphic retrograde to greenschist is marked by formation of chlorite, muscovite and prehnite. Residuum-rich metatexites show higher CaO and Na{sub 2}O contents, separating them from K{sub 2}O, Ba and Rb enriched transitional metatexites. U-Pb on zircon and Sm-Nd whole-rocks dating indicates that the residuum-rich metatexite crystallized at 1436 ± 11 Ma, with a T{sub DM} age of 1.90 Ga and ε{sub Nd(1.43)} of -0.54, whereas the dioritic injection crystallized at 1341,7 ± 17 Ma with a T{sub DM} age of 1.47 Ga and ε{sub Nd(1.34)} of 3.39. These results indicate that the Furna Azul Migmatite protolith was formed during the San Ignacio Orogeny and was reworked during the same orogeny, as basement for collisional to post-magmatic granites from Pensamiento Intrusive Suite. (author)

  4. Experimental and petrological constraints on local-scale interaction of biotite-amphibole gneiss with H2O-CO2-(K, NaCl fluids at middle-crustal conditions: Example from the Limpopo Complex, South Africa

    Directory of Open Access Journals (Sweden)

    Oleg G. Safonov

    2012-11-01

    Full Text Available Reaction textures and fluid inclusions in the ∼2.0 Ga pyroxene-bearing dehydration zones within the Sand River biotite-hornblende orthogneisses (Central Zone of the Limpopo Complex suggest that the formation of these zones is a result of close interplay between dehydration process along ductile shear zones triggered by H2O-CO2-salt fluids at 750–800 °C and 5.5–6.2 kbar, partial melting, and later exsolution of residual brine and H2O-CO2 fluids during melt crystallization at 650–700 °C. These processes caused local variations of water and alkali activity in the fluids, resulting in various mineral assemblages within the dehydration zone. The petrological observations are substantiated by experiments on the interaction of the Sand River gneiss with the H2O-CO2-(K, NaCl fluids at 750 and 800 °C and 5.5 kbar. It follows that the interaction of biotite-amphibole gneiss with H2O-CO2-(K, NaCl fluids is accompanied by partial melting at 750–800 °C. Orthopyroxene-bearing assemblages are characteristic for temperature 800 °C and are stable in equilibrium with fluids with low salt concentrations, while salt-rich fluids produce clinopyroxene-bearing assemblages. These observations are in good agreement with the petrological data on the dehydration zones within the Sand River orthogneisses.

  5. Characterization of adjacent breast tumors using oligonucleotide microarrays

    International Nuclear Information System (INIS)

    Unger, Meredith A; Rishi, Mazhar; Clemmer, Virginia B; Hartman, Jennifer L; Keiper, Elizabeth A; Greshock, Joel D; Chodosh, Lewis A; Liebman, Michael N; Weber, Barbara L

    2001-01-01

    Current methodology often cannot distinguish second primary breast cancers from multifocal disease, a potentially important distinction for clinical management. In the present study we evaluated the use of oligonucleotide-based microarray analysis in determining the clonality of tumors by comparing gene expression profiles. Total RNA was extracted from two tumors with no apparent physical connection that were located in the right breast of an 87-year-old woman diagnosed with invasive ductal carcinoma (IDC). The RNA was hybridized to the Affymetrix Human Genome U95A Gene Chip ® (12,500 known human genes) and analyzed using the Gene Chip Analysis Suite ® 3.3 (Affymetrix, Inc, Santa Clara, CA, USA) and JMPIN ® 3.2.6 (SAS Institute, Inc, Cary, NC, USA). Gene expression profiles of tumors from five additional patients were compared in order to evaluate the heterogeneity in gene expression between tumors with similar clinical characteristics. The adjacent breast tumors had a pairwise correlation coefficient of 0.987, and were essentially indistinguishable by microarray analysis. Analysis of gene expression profiles from different individuals, however, generated a pairwise correlation coefficient of 0.710. Transcriptional profiling may be a useful diagnostic tool for determining tumor clonality and heterogeneity, and may ultimately impact on therapeutic decision making

  6. A deterministic seismic hazard map of India and adjacent areas

    International Nuclear Information System (INIS)

    Parvez, Imtiyaz A.; Vaccari, Franco; Panza, Giuliano

    2001-09-01

    A seismic hazard map of the territory of India and adjacent areas has been prepared using a deterministic approach based on the computation of synthetic seismograms complete of all main phases. The input data set consists of structural models, seismogenic zones, focal mechanisms and earthquake catalogue. The synthetic seismograms have been generated by the modal summation technique. The seismic hazard, expressed in terms of maximum displacement (DMAX), maximum velocity (VMAX), and design ground acceleration (DGA), has been extracted from the synthetic signals and mapped on a regular grid of 0.2 deg. x 0.2 deg. over the studied territory. The estimated values of the peak ground acceleration are compared with the observed data available for the Himalayan region and found in good agreement. Many parts of the Himalayan region have the DGA values exceeding 0.6 g. The epicentral areas of the great Assam earthquakes of 1897 and 1950 represent the maximum hazard with DGA values reaching 1.2-1.3 g. (author)

  7. Earthquake response of adjacent structures with viscoelastic and friction dampers

    Directory of Open Access Journals (Sweden)

    Žigić Miodrag

    2015-01-01

    Full Text Available We study the seismic response of two adjacent structures connected with a dry friction damper. Each of them consists of a viscoelastic rod and a rigid block, which can slide without friction along the moving base. A simplified earthquake model is used for modeling the horizontal ground motion. Energy dissipation is taken by the presence of the friction damper, which is modeled by the set-valued Coulomb friction law. Deformation of viscoelastic rods during the relative motion of the blocks represents another way of energy dissipation. The constitutive equation of a viscoelastic body is described by the fractional Zener model, which includes fractional derivatives of stress and strain. The problem merges fractional derivatives as non-local operators and theory of set-valued functions as the non-smooth ones. Dynamical behaviour of the problem is governed by a pair of coupled multi-valued differential equations. The posed Cauchy problem is solved by use of the Grünwald-Letnikov numerical scheme. The behaviour of the system is analyzed for different values of system parameters.

  8. Repeated adjacent-segment degeneration after posterior lumbar interbody fusion.

    Science.gov (United States)

    Okuda, Shinya; Oda, Takenori; Yamasaki, Ryoji; Maeno, Takafumi; Iwasaki, Motoki

    2014-05-01

    One of the most important sequelae affecting long-term results is adjacent-segment degeneration (ASD) after posterior lumbar interbody fusion (PLIF). Although several reports have described the incidence rate, there have been no reports of repeated ASD. The purpose of this report was to describe 1 case of repeated ASD after PLIF. A 62-year-old woman with L-4 degenerative spondylolisthesis underwent PLIF at L4-5. At the second operation, L3-4 PLIF was performed for L-3 degenerative spondylolisthesis 6 years after the primary operation. At the third operation, L2-3 PLIF was performed for L-2 degenerative spondylolisthesis 1.5 years after the primary operation. Vertebral collapse of L-1 was detected 1 year after the third operation, and the collapse had progressed. At the fourth operation, 3 years after the third operation, vertebral column resection of L-1 and replacement of titanium mesh cages with pedicle screw fixation between T-4 and L-5 was performed. Although the patient's symptoms resolved after each operation, the time between surgeries shortened. The sacral slope decreased gradually although each PLIF achieved local lordosis at the fused segment.

  9. DNA sequence responsible for the amplification of adjacent genes.

    Science.gov (United States)

    Pasion, S G; Hartigan, J A; Kumar, V; Biswas, D K

    1987-10-01

    A 10.3-kb DNA fragment in the 5'-flanking region of the rat prolactin (rPRL) gene was isolated from F1BGH(1)2C1, a strain of rat pituitary tumor cells (GH cells) that produces prolactin in response to 5-bromodeoxyuridine (BrdU). Following transfection and integration into genomic DNA of recipient mouse L cells, this DNA induced amplification of the adjacent thymidine kinase gene from Herpes simplex virus type 1 (HSV1TK). We confirmed the ability of this "Amplicon" sequence to induce amplification of other linked or unlinked genes in DNA-mediated gene transfer studies. When transferred into the mouse L cells with the 10.3-5'rPRL gene sequence of BrdU-responsive cells, both the human growth hormone and the HSV1TK genes are amplified in response to 5-bromodeoxyuridine. This observation is substantiated by BrdU-induced amplification of the cotransferred bacterial Neo gene. Cotransfection studies reveal that the BrdU-induced amplification capability is associated with a 4-kb DNA sequence in the 5'-flanking region of the rPRL gene of BrdU-responsive cells. These results demonstrate that genes of heterologous origin, linked or unlinked, and selected or unselected, can be coamplified when located within the amplification boundary of the Amplicon sequence.

  10. Modern sedimentary processes along the Doce river adjacent continental shelf

    Directory of Open Access Journals (Sweden)

    Valéria da Silva Quaresma

    Full Text Available In areas of the continental shelf where sediment supply is greater than the sediment dispersion capacity, an extensive terrigenous deposits and consequently submerged deltas can be formed. The Eastern Brazilian shelf is characterized by the occurrence of river feed deltas in between starving coasts. Herein, modern sedimentary processes acting along the Doce river adjacent continental shelf are investigated. The main objective was to understand the shelf sediment distribution, recognizing distinct sedimentary patterns and the major influence of river sediment discharge in the formation of shelf deposits. The study used 98 surficial samples that were analyzed for grain size, composition and bulk density. Results revealed 3 distinct sectors: south - dominated by mud fraction with a recent deposition from riverine input until 30 m deep and from this depth bioclastic sands dominate; central north - sand mud dominated, been recognized as a bypass zone of resuspended sediment during high energy events; and north - relict sands with high carbonate content. The modern sedimentation processes along the Doce river continental shelf is dominated by distinct sedimentary regimes, showing a strong fluvial influence associated with wave/wind induced sediment dispersion and a carbonate regime along the outer shelf. These regimes seem to be controlled by the distance from the river mouth and bathymetric gradients.

  11. Oligocene paleogeography of the northern Great Plains and adjacent mountains

    International Nuclear Information System (INIS)

    Seeland, D.

    1985-01-01

    Early Oligocene paleogeography of the northern Great Plains and adjacent mountains is inferred in part from published surface and subsurface studies of the pre-Oligocene surface. These studies are combined with published and unpublished information on clast provenance, crossbedding orientation, and Eocene paleogeography. The Oligocene Arctic Ocean-Gulf of Mexico continental divide extended from the southern Absaroka Mountains east along the Owl Creek Mountains, across the southern Powder River Basin, through the northern Black Hills, and eastward across South Dakota. Streams north of the divide flowed northeastward. The Olligocene White River Group contains 50 to 90 percent airfall pyroclastic debris from a northern Great Basin source. Most of the uranium deposits of the region in pre-Oligocene rocks can be related to a uranium source in the volcanic ash of the White River; in many places the pre-Oligocene deposits can be related to specific Oligocene channels. Uranium deposits in sandstones of major Oligocene rivers are an important new type of deposit. The Oligocene channel sandstones also contain small quantities of gold, molybdenum, gas, and oil

  12. Mechanical interactions between adjacent airways in the lung.

    Science.gov (United States)

    Ma, Baoshun; Bates, Jason H T

    2014-03-15

    The forces of mechanical interdependence between the airways and the parenchyma in the lung are powerful modulators of airways responsiveness. Little is known, however, about the extent to which adjacent airways affect each other's ability to narrow due to distortional forces generated within the intervening parenchyma. We developed a two-dimensional computational model of two airways embedded in parenchyma. The parenchyma itself was modeled in three ways: 1) as a network of hexagonally arranged springs, 2) as a network of triangularly arranged springs, and 3) as an elastic continuum. In all cases, we determined how the narrowing of one airway was affected when the other airway was relaxed vs. when it narrowed to the same extent as the first airway. For the continuum and triangular network models, interactions between airways were negligible unless the airways lay within about two relaxed diameters of each other, but even at this distance the interactions were small. By contrast, the hexagonal spring network model predicted that airway-airway interactions mediated by the parenchyma can be substantial for any degree of airway separation at intermediate values of airway contraction forces. Evidence to date suggests that the parenchyma may be better represented by the continuum model, which suggests that the parenchyma does not mediate significant interactions between narrowing airways.

  13. Cryogun cryotherapy for oral leukoplakia and adjacent melanosis lesions.

    Science.gov (United States)

    Chen, Hsin-Ming; Cheng, Shih-Jung; Lin, Hung-Pin; Yu, Chuan-Hang; Wu, Yang-Che; Chiang, Chun-Pin

    2015-09-01

    Our previous study has shown that cryogun cryotherapy is a good and effective treatment modality for oral leukoplakia. In this study, we used cryogun cryotherapy to treat 72 oral leukoplakia and adjacent smoking-induced melanosis (OLM) lesions on the buccal mucosae. Of 72 OLM lesions, 14 had epithelial hyperplasia with parakeratosis, 24 had epithelial hyperplasia with hyperkeratosis, 26 had mild dysplasia, seven had moderate dysplasia, and one had severe dysplasia. Complete regression was achieved in all 72 OLM lesions after a mean of 3.3 ± 1.3 cryogun cryotherapy treatments. We found that OLM lesions in patients without smoking habit, with the greatest diameter cryotherapy treatment to achieve complete regression than those OLM lesions in patients with smoking habit, with the greatest diameter ≥ 2.8 cm, without epithelial dysplasia, or with a surface keratin thickness > 50 μm (all P-values cryotherapy treatment number (all P-values cryotherapy treatment required to achieve complete regression of the OLM lesion by multivariate logistic regression analyses. Cryogun cryotherapy is an effective treatment modality for OLM lesions. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. Flow and edge scour in current adjacent to stone covers

    DEFF Research Database (Denmark)

    Petersen, Thor U.; Sumer, B. Mutlu; Bøgelund, Jon

    2015-01-01

    This paper presents the results of an experimental investigation on edge scour adjacent to a stone cover laid on a sandy bed. The three-dimensional flow over the edge of the stone layer has been investigated by the use of particle image velocimetry. The flow measurements show a significant amount...... of turbulence in the primary flow near the junction between the stone layer and the sand bed and the formation of complex secondary-flow structures. The results show that the flow and the edge scour process in a steady current are governed by the size of the roughness elements and to some extent the side slope...... of the berm. The edge scour is caused by the combined action of the primary flow and the secondary flow. The primary flow stirs up the sediment and puts it into suspension, and the secondary flow carries it away from the junction between the stone layer and the sand bed, resulting in a scour hole forming...

  15. Review of vibration effect during piling installation to adjacent structure

    Science.gov (United States)

    Rahman, Nurul Aishah Abd; Musir, Adhilla Ainun; Dahalan, Nurol Huda; Ghani, Abdul Naser Abdul; Khalil, Muhamad Kasimi Abd

    2017-12-01

    Basically, many major structures across the world such as towers, high rise building, houses and bridges utilize pile as a support material. The use of pile is important to strengthen the structures. However, this has led to another problem to the nearest surrounding structures resulted from pile driving. As part of a construction work, unavoidable pile driving activity generates a vibration towards the surrounding structures if uncontrolled may cause damage to the adjacent structure. As the current construction works are frequently located in urban areas where the distance between the nearest building structures is not far, vibration may cause damage to nearby structures. Knowing which part of the building that is mostly affected by various vibration patterns from the impact of pile driving is crucial. Thus, it is very important to predict the impact of vibration during piling installation work. This paper reviews the vibrations generated by piling activity toward surrounding structures in terms sources of vibration, impact of piling installation, pile-soil interaction, and factors affecting the vibration impact of building as well as to study the parameters involved in vibration generation during piling works.

  16. Concentric network symmetry grasps authors' styles in word adjacency networks

    Science.gov (United States)

    Amancio, Diego R.; Silva, Filipi N.; Costa, Luciano da F.

    2015-06-01

    Several characteristics of written texts have been inferred from statistical analysis derived from networked models. Even though many network measurements have been adapted to study textual properties at several levels of complexity, some textual aspects have been disregarded. In this paper, we study the symmetry of word adjacency networks, a well-known representation of text as a graph. A statistical analysis of the symmetry distribution performed in several novels showed that most of the words do not display symmetric patterns of connectivity. More specifically, the merged symmetry displayed a distribution similar to the ubiquitous power-law distribution. Our experiments also revealed that the studied metrics do not correlate with other traditional network measurements, such as the degree or the betweenness centrality. The discriminability power of the symmetry measurements was verified in the authorship attribution task. Interestingly, we found that specific authors prefer particular types of symmetric motifs. As a consequence, the authorship of books could be accurately identified in 82.5% of the cases, in a dataset comprising books written by 8 authors. Because the proposed measurements for text analysis are complementary to the traditional approach, they can be used to improve the characterization of text networks, which might be useful for applications based on stylistic classification.

  17. A systematic review of definitions and classification systems of adjacent segment pathology.

    Science.gov (United States)

    Kraemer, Paul; Fehlings, Michael G; Hashimoto, Robin; Lee, Michael J; Anderson, Paul A; Chapman, Jens R; Raich, Annie; Norvell, Daniel C

    2012-10-15

    Systematic review. To undertake a systematic review to determine how "adjacent segment degeneration," "adjacent segment disease," or clinical pathological processes that serve as surrogates for adjacent segment pathology are classified and defined in the peer-reviewed literature. Adjacent segment degeneration and adjacent segment disease are terms referring to degenerative changes known to occur after reconstructive spine surgery, most commonly at an immediately adjacent functional spinal unit. These can include disc degeneration, instability, spinal stenosis, facet degeneration, and deformity. The true incidence and clinical impact of degenerative changes at the adjacent segment is unclear because there is lack of a universally accepted classification system that rigorously addresses clinical and radiological issues. A systematic review of the English language literature was undertaken and articles were classified using the Grades of Recommendation Assessment, Development, and Evaluation criteria. RESULTS.: Seven classification systems of spinal degeneration, including degeneration at the adjacent segment, were identified. None have been evaluated for reliability or validity specific to patients with degeneration at the adjacent segment. The ways in which terms related to adjacent segment "degeneration" or "disease" are defined in the peer-reviewed literature are highly variable. On the basis of the systematic review presented in this article, no formal classification system for either cervical or thoracolumbar adjacent segment disorders currently exists. No recommendations regarding the use of current classification of degeneration at any segments can be made based on the available literature. A new comprehensive definition for adjacent segment pathology (ASP, the now preferred terminology) has been proposed in this Focus Issue, which reflects the diverse pathology observed at functional spinal units adjacent to previous spinal reconstruction and balances

  18. Reassessment of the geologic evolution of selected precambrian terranes in Brazil, based on SHRIMP U-Pb data, part 2: mineiro and Aracuai orogens and Southern Sao Francisco craton

    International Nuclear Information System (INIS)

    Silva, Luiz Carlos da; Pimentel, Marcio; Armstrong, Richard; Noce, Carlos Mauricio; Pedrosa-Soares, Antonio Carlos; Carneiro, Mauricio Antonio

    2002-01-01

    This paper discusses new zircon SHRIMP (Sensitive High Resolution Ion Microprobe) U-Pb geochronological data for 19 key-exposures of several geological units exposed at the eastern border of the Southern Sao Francisco Craton and at the adjacent Proterozoic Mineiro and Aracuai orogens. Samples were collected along several E-W tran sects, aiming at tracing the precise limit of the Sao Francisco Craton Archean basement, as well as assessing the extension of the successive proterozoic orogenic collages. Due to the complex geologic history and/or high grade metamorphism which most of the rock units investigated have undergone, zircon morphology and the U-Pb analytical data exhibit very complex patterns. These are characterized by a combination of inheritance, partial resetting and new zircon growth during high-grade metamorphism. As a consequence, very careful and detailed analyses of cathodoluminescence imagery were required to allow distinction between inheritance, newly melt-precipitated zircon and partially reset zircons, as well as between the ages of magmatic and metamorphic events. In the southeastern border of the craton 5 units yielded Archean crystallization ages ranging from ca. 3000-2700 Ma, with poorly constrained metamorphic ages ranging from ca. 2850 to 550 Ma. The TTG gneissic complex exposed to the east and south of the Quadrilatero Ferrifero, formerly ascribed to the Archean basement, have crystallization ages from ca. 2210 Ma to 2050 Ma, and can now be interpreted as representing pre- to syn-collisional magmatic phases of the Mineiro Belt. Metamorphic ages of ca. 2100 Ma and 560 Ma are also well constrained in zircon populations from these gneisses. The crystallization age of ca 1740 Ma observed for an alkaline granite of the Borrachudos Suite (intrusive into the Archean basement east of the Southern Espinhaco Range) confirmed previous conventional U-Pb data for this Paleoproterozoic rift-related magmatism. One of the major basement inliers within the

  19. Adjacent-segment disease after thoracic pedicle screw fixation.

    Science.gov (United States)

    Agarwal, Nitin; Heary, Robert F; Agarwal, Prateek

    2018-03-01

    OBJECTIVE Pedicle screw fixation is a technique widely used to treat conditions ranging from spine deformity to fracture stabilization. Pedicle screws have been used traditionally in the lumbar spine; however, they are now being used with increasing frequency in the thoracic spine as a more favorable alternative to hooks, wires, or cables. Although safety concerns, such as the incidence of adjacent-segment disease (ASD) after cervical and lumbar fusions, have been reported, such issues in the thoracic spine have yet to be addressed thoroughly. Here, the authors review the literature on ASD after thoracic pedicle screw fixation and report their own experience specifically involving the use of pedicle screws in the thoracic spine. METHODS Select references from online databases, such as PubMed (provided by the US National Library of Medicine at the National Institutes of Health), were used to survey the literature concerning ASD after thoracic pedicle screw fixation. To include the authors' experience at Rutgers New Jersey Medical School, a retrospective review of a prospectively maintained database was performed to determine the incidence of complications over a 13-year period in 123 consecutive adult patients who underwent thoracic pedicle screw fixation. Children, pregnant or lactating women, and prisoners were excluded from the review. By comparing preoperative and postoperative radiographic images, the occurrence of thoracic ASD and disease within the surgical construct was determined. RESULTS Definitive radiographic fusion was detected in 115 (93.5%) patients. Seven incidences of instrumentation failure and 8 lucencies surrounding the screws were observed. One patient was observed to have ASD of the thoracic spine. The mean follow-up duration was 50 months. CONCLUSIONS This long-term radiographic evaluation revealed the use of pedicle screws for thoracic fixation to be an effective stabilization modality. In particular, ASD seems to be less of a problem in the

  20. Tidally influenced alongshore circulation at an inlet-adjacent shoreline

    Science.gov (United States)

    Hansen, Jeff E.; Elias, Edwin P.L.; List, Jeffrey H.; Erikson, Li H.; Barnard, Patrick L.

    2013-01-01

    The contribution of tidal forcing to alongshore circulation inside the surfzone is investigated at a 7 km long sandy beach adjacent to a large tidal inlet. Ocean Beach in San Francisco, CA (USA) is onshore of a ∼150 km2 ebb-tidal delta and directly south of the Golden Gate, the sole entrance to San Francisco Bay. Using a coupled flow-wave numerical model, we find that the tides modulate, and in some cases can reverse the direction of, surfzone alongshore flows through two separate mechanisms. First, tidal flow through the inlet results in a barotropic tidal pressure gradient that, when integrated across the surfzone, represents an important contribution to the surfzone alongshore force balance. Even during energetic wave conditions, the tidal pressure gradient can account for more than 30% of the total alongshore pressure gradient (wave and tidal components) and up to 55% during small waves. The wave driven component of the alongshore pressure gradient results from alongshore wave height and corresponding setup gradients induced by refraction over the ebb-tidal delta. Second, wave refraction patterns over the inner shelf are tidally modulated as a result of both tidal water depth changes and strong tidal flows (∼1 m/s), with the effect from currents being larger. These tidally induced changes in wave refraction result in corresponding variability of the alongshore radiation stress and pressure gradients within the surfzone. Our results indicate that tidal contributions to the surfzone force balance can be significant and important in determining the direction and magnitude of alongshore flow.

  1. FSH: fast spaced seed hashing exploiting adjacent hashes.

    Science.gov (United States)

    Girotto, Samuele; Comin, Matteo; Pizzi, Cinzia

    2018-01-01

    Patterns with wildcards in specified positions, namely spaced seeds , are increasingly used instead of k -mers in many bioinformatics applications that require indexing, querying and rapid similarity search, as they can provide better sensitivity. Many of these applications require to compute the hashing of each position in the input sequences with respect to the given spaced seed, or to multiple spaced seeds. While the hashing of k -mers can be rapidly computed by exploiting the large overlap between consecutive k -mers, spaced seeds hashing is usually computed from scratch for each position in the input sequence, thus resulting in slower processing. The method proposed in this paper, fast spaced-seed hashing (FSH), exploits the similarity of the hash values of spaced seeds computed at adjacent positions in the input sequence. In our experiments we compute the hash for each positions of metagenomics reads from several datasets, with respect to different spaced seeds. We also propose a generalized version of the algorithm for the simultaneous computation of multiple spaced seeds hashing. In the experiments, our algorithm can compute the hashing values of spaced seeds with a speedup, with respect to the traditional approach, between 1.6[Formula: see text] to 5.3[Formula: see text], depending on the structure of the spaced seed. Spaced seed hashing is a routine task for several bioinformatics application. FSH allows to perform this task efficiently and raise the question of whether other hashing can be exploited to further improve the speed up. This has the potential of major impact in the field, making spaced seed applications not only accurate, but also faster and more efficient. The software FSH is freely available for academic use at: https://bitbucket.org/samu661/fsh/overview.

  2. Folding and fracturing of rock adjacent to salt diapirs

    Science.gov (United States)

    Rowan, Mark G.

    2017-04-01

    When John Ramsay wrote his groundbreaking book in 1967, deformation around salt diapirs was not something he covered. At the time, most geologists considered diapirs to form due to density inversion, rising through thick overlying strata due to buoyancy. In doing so, salt was thought to shove aside the younger rocks, shearing and fracturing them in drag folds and supposedly producing "salt gouge". Even after it was realized that the majority of diapirs spend most of their history growing at or just beneath the surface, the relative rise of salt and sinking of minibasins were (and are) still thought by many to be accommodated in part by shear and fracturing of rocks in a collar zone around the salt. There are two arguments against this model. The first is mechanical: whereas halite behaves as a viscous fluid, even young sediment deforms as a brittle material with layer anisotropy. Thus, the salt-sediment interface is the outer margin of an intrasalt shear zone caused by viscous drag against the diapir margin. The velocity of salt flow decreases dramatically toward the edge of the diapir, so that the outermost salt effectively doesn't move. Hence, no shear or fracturing is expected in surrounding strata. The second and more important argument is that empirical field data do not support the idea of drag folds and associated deformation. Certainly, strata are typically folded and thinned adjacent to diapirs. However, stratal upturn is generated by monoclinal drape folding of the diapir roof over the edge of the rising salt, and thinning is caused by deposition onto the bathymetric highs formed by the diapirs, often supplemented by roof erosion and slumping. Halokinetic sequences observed in numerous salt basins (e.g., Paradox Basin, La Popa Basin, Spanish Pyrenees, Sivas Basin, Zagros Mountains, Kuqa Basin) contain no diapir-parallel shear zones and minimal thinning and fracturing caused by diapir rise. Even megaflaps, in which strata extend for kilometers up the sides

  3. Impact of body mass index on adjacent segment disease after lumbar fusion for degenerative spine disease.

    Science.gov (United States)

    Ou, Chien-Yu; Lee, Tao-Chen; Lee, Tsung-Han; Huang, Yu-Hua

    2015-04-01

    Adjacent segment disease is an important complication after fusion of degenerative lumbar spines. However, the role of body mass index (BMI) in adjacent segment disease has been addressed less. To examine the relationship between BMI and adjacent segment disease after lumbar fusion for degenerative spine diseases. For this retrospective study, we enrolled 190 patients undergoing lumbar fusion surgery for degeneration. BMI at admission was documented. Adjacent segment disease was defined by integration of the clinical presentations and radiographic criteria based on the morphology of the dural sac on magnetic resonance images. Adjacent segment disease was identified in 13 of the 190 patients, accounting for 6.8%. The interval between surgery and diagnosis as adjacent segment disease ranged from 21 to 66 months. Five of the 13 patients required subsequent surgical intervention for clinically relevant adjacent segment disease. In the logistic regression model, BMI was a risk factor for adjacent segment disease after lumbar fusion for degenerative spine diseases (odds ratio, 1.68; 95% confidence interval, 1.27-2.21; P disease rate by 67.6%. The patients were subdivided into 2 groups based on BMI, and up to 11.9% of patients with BMI ≥ 25 kg/m were diagnosed as having adjacent segment disease at the last follow-up. BMI is a risk factor for adjacent segment disease in patients undergoing lumbar fusion for degenerative spine diseases. Because BMI is clinically objective and modifiable, controlling body weight before or after surgery may provide opportunities to reduce the rate of adjacent segment disease and to improve the outcome of fusion surgery.

  4. New evidence for Oligocene to Recent slip along the San Juan fault, a terrane-bounding structure within the Cascadia forearc of southern British Columbia, Canada

    Science.gov (United States)

    Harrichhausen, N.; Morell, K. D.; Regalla, C.; Lynch, E. M.

    2017-12-01

    Active forearc deformation in the southern Cascadia subduction zone is partially accommodated by faults in the upper crust in both Washington state and Oregon, but until recently, these types of active forearc faults have not been documented in the northern part of the Cascadia forearc on Vancouver Island, British Columbia. Here we present new evidence for Quaternary slip on the San Juan fault that indicates that this terrane-bounding structure has been reactivated since its last documented slip in the Eocene. Field work targeted by newly acquired hi-resolution lidar topography reveals a deformed debris flow channel network developed within colluvium along the central portion of the San Juan fault, consistent with a surface-rupturing earthquake with 1-2 m of offset since deglaciation 13 ka. Near the western extent of the San Juan fault, marine sediments are in fault contact with mélange of the Pandora Peak Unit. These marine sediments are likely Oligocene or younger in age, given their similarity in facies and fossil assemblages to nearby outcrops of the Carmanah Group sediments, but new dating using strontium isotope stratigraphy will confirm this hypothesis. If these sediments are part of the Carmanah Group, they occur further east and at a higher elevation than previously documented. The presence of Oligocene or younger marine sediments, more than 400 meters above current sea level, requires a substantial amount of Neogene rock uplift that could have been accommodated by slip on the San Juan fault. A preliminary analysis of fault slickensides indicates a change in slip sense from left-lateral to normal along the strike of the fault. Until further mapping and analysis is completed, however, it remains unclear whether this kinematic change reflects spatial and/or temporal variability. These observations suggest that the San Juan fault is likely part of a network of active faults accommodating forearc strain on Vancouver Island. With the recent discovery of

  5. Timing of metamorphism and exhumation in the Nordøyane ultra-high-pressure domain, Western Gneiss Region, Norway: New constraints from complementary CA-ID-TIMS and LA-MC-ICP-MS geochronology

    Science.gov (United States)

    Butler, J. P.; Jamieson, R. A.; Dunning, G. R.; Pecha, M. E.; Robinson, P.; Steenkamp, H. M.

    2018-06-01

    We present the results of a combined CA-ID-TIMS and LA-MC-ICP-MS U-Pb geochronology study of zircon and associated rutile and titanite from the Nordøyane ultra-high-pressure (UHP) domain in the Western Gneiss Region (WGR) of Norway. The dated samples include 4 eclogite bodies, 2 host-rock migmatites, and 2 cross-cutting pegmatites and leucosomes, all from the island of Harøya. Zircon from a coesite eclogite yielded an age of ca. 413 Ma, interpreted as the time of UHP metamorphism in this sample. Zircon data from the other eclogite bodies yielded metamorphic ages of ca. 413 Ma, 407 Ma, and 406 Ma; zircon trace-element data associated with 413 Ma and 407 Ma ages are consistent with eclogite-facies crystallization. In all of the eclogites, U-Pb dates from zircon cores, interpreted as the times of protolith crystallization, range from ca. 1680-1586 Ma, consistent with Gothian ages from orthogneisses in Nordøyane and elsewhere in the WGR. A zircon core age of ca. 943 Ma from one sample agrees with Sveconorwegian ages of felsic gneisses and pegmatites in the western part of the area. Migmatites hosting the eclogite bodies yielded zircon core ages of ca. 1657-1591 Ma and rim ages of ca. 395-392 Ma, interpreted as the times of Gothian protolith formation and Scandian partial melt crystallization, respectively. Pegmatite in an eclogite boudin neck yielded a crystallization age of ca. 388 Ma, interpreted as the time of melt crystallization. Rutile and titanite from 3 samples (an eclogite and two migmatites) yielded concordant ID-TIMS ages of 378-376 Ma. The results are similar to existing U-Pb data from other Nordøyane eclogites (415-405 Ma). In combination with previous pressure-temperature data from the coesite eclogite, these ages indicate that peak metamorphic conditions of 3 GPa/760 °C were reached ca. 413 Ma, followed by decompression to 1 GPa/810 °C by ca. 397 Ma and cooling below ca. 600 °C by ca. 375 Ma. The results are compatible with protracted UHP

  6. Cordilleran metamorphic core complexes and their uranium favorability. Final report

    International Nuclear Information System (INIS)

    Coney, P.J.; Reynolds, S.J.

    1980-11-01

    The objective of this report is to provide a descriptive body of knowledge on Cordilleran metamorphic core complexes including their lithologic and structural characteristics, their distribution within the Cordillera, and their evolutionary history and tectonic setting. The occurrence of uranium in the context of possibility for uranium concentration is also examined. Chapter 1 is an overview of Cordilleran metamorphic core complexes which describes their physical characteristics, tectonic setting and geologic history. This overview is accompanied by a tectonic map. Chapter 2 is a discussion of the mantled gneiss dome concept. The purpose of including this work is to provide a basic history of this concept and to describe the characteristics and distribution of gneiss domes throughout the world to enable one to compare and contrast them with the metamorphic core complexes as discussed in this report. Some gneiss domes are known producers of uranium (as are also some core complexes). Chapter 3 is an examination of the effects of the core complex process on adjacent sedimentary and volcanic cover terranes. Also included is a discussion of the kinematic significance of these cover terranes as they are related to process within the cores of the complexes. Some of the cover terranes have uranium prospects in them. Chapter 4 is a detailed discussion of uranium in Cordilleran metamorphic core complexes and includes the conceptual basis for the various types of occurrences and the processes that might favor concentration of uranium. The report is supported by a 5-part Appendix. The majority of the core complexes discussed in this report either do not appear or are not recognizable on existing published geologic maps

  7. Magnetotelluric Investigation in the Jiyang Depression and its Adjacent Areas

    Science.gov (United States)

    Zhang, L.; Hao, T.; Duan, Q.

    2008-12-01

    The Jiyang Depression is a secondary tectonic unit of the Bohai Bay Basin, and is a Mesozoic-Cenozoic continental-facie depositional depression. The Jiyang Depression consists of the Dongying, Zanhua, Chezhen, and Huimin sags, and the Yihezhuang, Chenjiazhuang, Qingcheng, Binxian, Guangrao, Shouguang, and heaves. In order to delineate shallow and deep structures of the depression, we conduct a magnetotelluric (MT) investigation in the Jiyang Depression and its adjacent areas. We use a remote reference setup to reduce noise disturbance, when several magnetotelluric sounding stations are measuring synchronously at different sites. The acquired MT data are to be processed and interpreted. We execute time series processing with the remote reference technique. The surveyed area is seriously interfered by noise. To improve quality of the data, we perform noise identification and manual selection of the time series segments. Identification of polarization modes is an important task for MT data qualitative interpretation. We apply for a PCA (principal component analysis) based method to automatically identify apparent polarized resistivity curves of TE and TM modes. The method recognizes the distortion and major variation of TE and TM curves and distinguishes the two kinds of curves with principal component analysis. From the apparent resistivity-frequency profile result, we can see that the Chenning Uplift and the Chenjiazhuang Heave reveal a 3-layered structure of medium-low-high, from the shallow to the deep. The structure is especially distinct for the Chenning Uplift, where there is a laterally steady-spreading high- resistivity zone corresponding to the frequency band lower than 1 Hz. The Dongying Sag is characteristic of high-low-medium from the shallow to the deep, and has a low-resistivity anomaly zone with obvious and wide lateral extending in the medium frequency band, which reflects that the deposition thickness of the basin is relatively big. The Guangrao

  8. Treatment Outcome and Patient Satisfaction with Two Adjacent Implant-Supported Restorations in the Esthetic Zone

    NARCIS (Netherlands)

    Tymstra, Nynke; Meijer, Henny J. A.; Stellingsma, Kees; Raghoebar, Gerry M.; Vissink, Arjan

    2010-01-01

    The purpose of this study was to evaluate the clinical and radiographic parameters as well as the esthetic outcome of two adjacent implant-supported restorations and the surrounding peri-implant mucosa in the maxillary esthetic zone. Ten patients were treated with two adjacent implants in the

  9. Variable length adjacent partitioning for PTS based PAPR reduction of OFDM signal

    International Nuclear Information System (INIS)

    Ibraheem, Zeyid T.; Rahman, Md. Mijanur; Yaakob, S. N.; Razalli, Mohammad Shahrazel; Kadhim, Rasim A.

    2015-01-01

    Peak-to-Average power ratio (PAPR) is a major drawback in OFDM communication. It leads the power amplifier into nonlinear region operation resulting into loss of data integrity. As such, there is a strong motivation to find techniques to reduce PAPR. Partial Transmit Sequence (PTS) is an attractive scheme for this purpose. Judicious partitioning the OFDM data frame into disjoint subsets is a pivotal component of any PTS scheme. Out of the existing partitioning techniques, adjacent partitioning is characterized by an attractive trade-off between cost and performance. With an aim of determining effects of length variability of adjacent partitions, we performed an investigation into the performances of a variable length adjacent partitioning (VL-AP) and fixed length adjacent partitioning in comparison with other partitioning schemes such as pseudorandom partitioning. Simulation results with different modulation and partitioning scenarios showed that fixed length adjacent partition had better performance compared to variable length adjacent partitioning. As expected, simulation results showed a slightly better performance of pseudorandom partitioning technique compared to fixed and variable adjacent partitioning schemes. However, as the pseudorandom technique incurs high computational complexities, adjacent partitioning schemes were still seen as favorable candidates for PAPR reduction

  10. Variable length adjacent partitioning for PTS based PAPR reduction of OFDM signal

    Energy Technology Data Exchange (ETDEWEB)

    Ibraheem, Zeyid T.; Rahman, Md. Mijanur; Yaakob, S. N.; Razalli, Mohammad Shahrazel; Kadhim, Rasim A. [School of Computer and Communication Engineering, Universiti Malaysia Perlis, 02600 Arau, Perlis (Malaysia)

    2015-05-15

    Peak-to-Average power ratio (PAPR) is a major drawback in OFDM communication. It leads the power amplifier into nonlinear region operation resulting into loss of data integrity. As such, there is a strong motivation to find techniques to reduce PAPR. Partial Transmit Sequence (PTS) is an attractive scheme for this purpose. Judicious partitioning the OFDM data frame into disjoint subsets is a pivotal component of any PTS scheme. Out of the existing partitioning techniques, adjacent partitioning is characterized by an attractive trade-off between cost and performance. With an aim of determining effects of length variability of adjacent partitions, we performed an investigation into the performances of a variable length adjacent partitioning (VL-AP) and fixed length adjacent partitioning in comparison with other partitioning schemes such as pseudorandom partitioning. Simulation results with different modulation and partitioning scenarios showed that fixed length adjacent partition had better performance compared to variable length adjacent partitioning. As expected, simulation results showed a slightly better performance of pseudorandom partitioning technique compared to fixed and variable adjacent partitioning schemes. However, as the pseudorandom technique incurs high computational complexities, adjacent partitioning schemes were still seen as favorable candidates for PAPR reduction.

  11. 33 CFR 110.168 - Hampton Roads, Virginia and adjacent waters (Datum: NAD 83).

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Hampton Roads, Virginia and adjacent waters (Datum: NAD 83). 110.168 Section 110.168 Navigation and Navigable Waters COAST GUARD..., Virginia and adjacent waters (Datum: NAD 83). (a) Anchorage Grounds—(1) Anchorage A [Naval Anchorage]. The...

  12. ''Dural tail'' adjacent to acoustic neuroma on MRI: a case report

    International Nuclear Information System (INIS)

    Lunardi, P.; Mastronardi, L.; Nardacci, B.; Acqui, M.; Fortuna, A.

    1993-01-01

    A 'dural tail' on Gd-DTPA-enhanced MRI has been often observed adjacent to meningiomas and considered to be useful in distinguishing meningioma of the cerebellopontine angle from acoustic neuroma. However, demonstration of a dural tail adjacent to an acoustic neuroma indicates that this sign is not specific. (orig.)

  13. Fluorides leaching from restorative materials and the effect on adjacent teeth

    DEFF Research Database (Denmark)

    Qvist, Vibeke; Poulsen, Agneta; Teglers, Poul Thorpen

    2010-01-01

    Placing a Class II restoration in a tooth changes the local environment, including that for the adjacent tooth. Apart from the change to a less- or non-cariogenic environment for the restored tooth, the effect of leachable components from a restoration in the adjacent tooth should be taken into c...

  14. Rb-Sr whole-rock and mineral ages, K-Ar, 40Ar/39Ar, and U-Pb mineral ages, and strontium, lead, neodymium, and oxygen isotopic compositions for granitic rocks from the Salinian Composite Terrane, California:

    Science.gov (United States)

    Kistler, R.W.; Champion, D.E.

    2001-01-01

    This report summarizes new and published age and isotopic data for whole-rocks and minerals from granitic rocks in the Salinian composite terrane, California. Rubidium-strontium whole-rock ages of plutons are in two groups, Early Cretaceous (122 to 100 Ma) and Late Cretaceous (95 to 82 Ma). Early Cretaceous plutons occur in all granitic rock exposures from Bodega Head in the north to those from the Santa Lucia and Gabilan Ranges in the central part of the terrane. Late Cretaceous plutons have been identified in the Point Reyes Peninsula, the Santa Lucia and the Gabilan Ranges, and in the La Panza Range in the southern part of the terrane. Ranges of initial values of isotopic compositions are 87Sr/86Sr, 0.7046-0.7147, δ18O, +8.5 to +12.5 per mil, 206Pb/204Pb, 18.901-19.860, 207Pb/204Pb, 15.618-15.814, 208Pb/204Pb, 38.569- 39.493, and εNd, +0.9 to -8.6. The initial 87Sr/86Sr=0.706 isopleth is identified in the northern Gabilan Range and in the Ben Lomond area of the Santa Cruz Mountains, in Montara Mountain, in Bodega Head, and to the west of the Farallon Islands on the Cordell Bank. This isotopic boundary is offset about 95 miles (160km) by right-lateral displacements along the San Gregorio-Hosgri and San Andreas fault systems.

  15. Constructing an optimal facility layout to maximize adjacency as a function of common boundary length

    Science.gov (United States)

    Ghassemi Tari, Farhad; Neghabi, Hossein

    2018-03-01

    An effective facility layout implies that departments with high flow are laid adjacent. However, in the case of a very narrow boundary length between the neighbouring departments, the adjacency would actually be useless. In traditional layout design methods, a score is generally assigned independent of the department's boundary length. This may result in a layout design with a restricted material flow. This article proposes a new concept of adjacency in which the department pairs are laid adjacent with a wider path. To apply this concept, a shop with unequal rectangular departments is contemplated and a mathematical programming model with the objective of maximizing the sum of the adjacency degrees is proposed. A computational experiment is conducted to demonstrate the efficiency of the layout design. It is demonstrated that the new concept provides a more efficient and a more realistic layout design.

  16. Comparison through fission-track analysis of portions of Australia and Antarctica adjacent prior to continental drift

    International Nuclear Information System (INIS)

    Stump, E.; Fitzgerald, P.G.

    1990-01-01

    Australia and Antarctica have been reconstructed by the matching of three terranes in western Victoria with three terranes in northern Victoria Land. Apparent fission-track ages from granitic rocks of these matched regions are compared. In western Victoria, Australia, data reflect a history of slow cooling following intrusion in early to middle Paleozoic time. In northern Victoria Land, Antarctica, a complex history of cooling and uplift is indicated, with uplift of the present-day mountains commencing approximately 50 Ma. Fission tracks in apatites from most samples from northern Victoria Land were completely re-set to zero by the thermal effects of Jurassic tholeiitic magmatism. Apatite in three samples however, predate the Jurassic and were only partially re-set by this event. Apparent sphene fission-track ages indicate that the three terranes in northern Victoria Land have shared a common thermal history since the Devonian. With the exception of one small area in western Victoria, neither western Victoria nor northern Victoria Land data show a clear influence of rifting and breakup in the late Cretaceous. Overall, the data indicate that once the breakup of Australia and Antarctica had occurred, their thermal and tectonic histories evolved independently along differing paths. (author)

  17. Adjacent field separations for homogenous dose distribution at particular depth and associated hot and cold spots

    International Nuclear Information System (INIS)

    Supe, S.S.; Deka, A.C.; Deka, B.C.; Sathiyanaranyanan, V.K.

    1991-01-01

    In radiotherapy treatment planning we come across many situations when treatment is given by using two adjacent fields, for e.g. for treatment of Hodgkin's disease. A pair of adjacent field have been used regularly for the treatment of ovarian tumours. A small separation is given at the skin level, otherwise hot spots are observed at the depth of interest. The separation depend upon tumour depths, and source to skin distance (SSD). Formulae have been derived for the separation as well as for hot and cold spots. The case of adjacent field becomes more complicated when anterior as well as posterior adjacent fields are used. It is not completely possible to avoid the hot and cold spots in such cases. This is partially avoided by shifting the gap on the skin surface during the course of treatment. (author). 2 refs., 2 tabs

  18. Incidence of root canal treatment of second molars following adjacent impacted third molar extraction

    Directory of Open Access Journals (Sweden)

    Yener Oguz

    2016-03-01

    Conclusion: Although the incidence is minimal, iatrogenic subluxation injuries occurring during the surgical removal of impacted third molars can lead to pulpal complications and a requirement for root canal treatment of adjacent second molars.

  19. 76 FR 74585 - Railroad Workplace Safety; Adjacent-Track On-Track Safety for Roadway Workers

    Science.gov (United States)

    2011-11-30

    ... impression that adjacent-track on-track safety was in effect, but it was not, due to a miscommunication. Of... the solution to the problem.'' And while the RWP Working Group did in fact draft this language, and...

  20. 31. Introduction with adjacent production of foundry and rolling department of electrolysis shop

    International Nuclear Information System (INIS)

    Ivanov, A.V.

    1993-01-01

    The introduction with adjacent production of foundry and rolling department of electrolysis shop was conducted. The foundry machine was described. The chemical properties of aluminium for ferrous alloy production were defined.

  1. Numerical Simulation of Salinity and Dissolved Oxygen at Perdido Bay and Adjacent Coastal Ocean

    Science.gov (United States)

    Environmental Fluid Dynamic Code (EFDC), a numerical estuarine and coastal ocean circulation hydrodynamic model, was used to simulate the distribution of the salinity, temperature, nutrients and dissolved oxygen (DO) in Perdido Bay and adjacent Gulf of Mexico. External forcing fa...

  2. The Park Volcanics Group : field relations of an igneous suite emplaced in the Triassic-Jurassic Murihiku Terrane, South Island, New Zealand

    International Nuclear Information System (INIS)

    Coombs, D.S.; Cook, N.D.J.; Campbell, J.D.

    1992-01-01

    Park Volcanics Group is proposed for igneous rocks, either shallow intrusive or extrusive, emplaced in the Murihiku Terrane during Triassic-Jurassic times. The term replaces Park Intrusives of Mutch, some members of which are shown to be extrusive rather than intrusive. Formation status within the group is given to Gowan Andesite and Pinney Volcanics (new names) in western Southland, Glenham Porphyry in eastern Southland, and Barnicoat Andesite (new) in the Richmond area, Nelson. Gowan Andesite is a porphyritic feldspar two-pyroxene andesite with a glassy or microcrystalline groundmass. A suite of low-grade metavolcanic rocks which forms the main mass of Malakoff Hill and which has formerly been included in the 'Park Intrusives' is here excluded and ascribed to the Takitimu Group; representative chemical data are given. Glenham Porphyry is typically a porphyritic feldspar two-pyroxene andesite texturally similar to the Gowan Andesite but with significant geochemical differences. Two volumetrically minor members are recognised, Habukinini Trachydacite and Kenilworth Rhyolite. In the north of its outcrop area, Glenham Porphyry is emplaced on or into Late Triassic terrestrial beds; in the middle it overlies Kaihikuan (Middle Triassic) and is overlain by Otapirian (latest Triassic) marine beds; and in the southeast it is directly overlain by Ururoan (late Early to early Middle Jurassic) conglomerates and marine sandstones. Pinney Volcanics are restricted to a very few, probably one, massive conglomeratic horizon in the Oretian Stage. The commonest rock type is a two-pyroxene trachydacite, modified by very-low-grade burial metamorphism. Auto-brecciation is characteristic and rock types change over short distances. Hornblende-rich variants occur as well as more felsic varieties including rhyolite ignimbrite. These may have been erupted onto a bouldery floodplain or shallow-marine surface, but alternatively may have been mass-emplaced by debris avalanche resulting from

  3. Devonian granitoids and their hosted mafic enclaves in the Gorny Altai terrane, northwestern Central Asian Orogenic Belt: crust-mantle interaction in a continental arc setting

    Science.gov (United States)

    Chen, Ming; Sun, Min

    2016-04-01

    Granitoids are a major component in the upper continental crust and hold key information on how did the continental crust grow and differentiate. This study focuses on the Yaloman intrusive complex from the Gorny Altai terrane, northwestern Central Asian Orogenic Belt (CAOB). The association of granitoids and mafic enclaves can provide important clues on the source nature, petrogenetic processes and geodynamic setting of the Yaloman intrusive complex, which in turn will shed light on the crustal evolution in the northwestern CAOB. Zircon U-Pb dating shows that the granitoids, including quartz diorites and granodiorites, were emplaced in ca. 389-387 Ma. The moderate Na2O + K2O contents and low A/CNK values indicate that these rocks belong to the sub-alkaline series with metaluminous to weakly peraluminous compositions. The granitoids yield two-stage zircon Hf model ages of ca. 0.79-1.07 Ga and whole-rock Nd model ages of ca. 0.90-0.99 Ga, respectively, implying that they were mainly sourced from Neoproterozoic juvenile crustal materials. The mafic enclaves show an almost identical crystallization age of ca. 389 Ma. The identification of coarse-grained xenocrysts and acicular apatites, together with the fine-grained texture, makes us infer that these enclaves are likely to represent magmatic globules commingled with the host magmas. The low SiO2 and high MgO contents of the mafic enclaves further suggest that substantial mantle-derived mafic melts were probably involved in their formation. Importantly, the SiO2 contents of the granitoids and mafic enclaves are well correlated with other major elements and most of the trace elements. Also a broadly negative correlation exists between the SiO2 contents and whole-rock epsilon Nd (390 Ma) values of the granitoids. Given the observation of reversely zoned plagioclases within the granitoids and the common occurrence of igneous mafic enclaves, we propose that magma mixing probably played an important role in the formation

  4. What can the Cretaceous-to-present latitude history of the Lhasa terrane tell us about plate-scale deformation in the Tibetan-Himalayan orogen? (Invited)

    Science.gov (United States)

    Lippert, P. C.; Van Hinsbergen, D. J.; Dupont-Nivet, G.; Huang, W.

    2013-12-01

    Published paleomagnetic data from well-dated sedimentary and volcanic rocks from the Lhasa terrane have been re-evaluated in a statistically consistent framework to assess the latitude history of southern Tibet from ~110 Ma to the present. We apply a methodology similar to the one used by the Time-Averaged geomagnetic Field Initiative to each paleomagnetic data set to establish coherency within and between paleomagnetic data from Tibet (see Session T023 for more details). Moreover, we use only sedimentary data that have been evaluated for and, where necessary, corrected for sedimentary inclination shallowing. The resulting apparent polar wander path (APWP) shows that the southern margin of the Lhasa terrane at the longitudes of Nepal remained at 20×4°N latitude from ~110 to at least 50 Ma and subsequently drifted northward to its present latitude of 29°N. This latitude history provides a paleomagnetically-determined collision age between the Tibetan Himalaya and the southern margin of Asia that is 49.5×4.5 Ma at 21×4° N latitude. The paleomagnetic age and latitude of this collision may be a few millions of years earlier and ~2° lower if estimates for shortening within the suture zone are considered. When compared to the global APWP of Torsvik et al. (2012) in Eurasian coordinates, the Lhasa APWP indicates that at most 1100×560 km of post-50 Ma India-Asia convergence was partitioned into Asian lithosphere. The lower bound of these paleomagnetic estimates is consistent with the magnitude of upper crustal shortening within Asia calculated from orogen-scale geological reconstructions. An implication is that 1700×560 km or more post-50 Ma India-Asia convergence was partitioned into Greater India. Paleomagnetic data from the Tibetan Himalaya are consistent with >2000 km of extension of Greater Indian lithosphere after break-up from Gondwana but prior to collision with the southern margin of Asia. Cenozoic subduction of this Cretaceous extensional basin following

  5. Late Triassic porphyritic intrusions and associated volcanic rocks from the Shangri-La region, Yidun terrane, Eastern Tibetan Plateau: Adakitic magmatism and porphyry copper mineralization

    Science.gov (United States)

    Wang, Bai-Qiu; Zhou, Mei-Fu; Li, Jian-Wei; Yan, Dan-Ping

    2011-11-01

    Early Mesozoic porphyritic intrusions in the Shangri-La region, southern Yidun terrane, SW China, are spatially associated with andesites and dacites. These intrusions are composed of diorite and quartz diorite, and are closely related to copper mineralization. LA-ICP-MS zircon U-Pb ages of the intrusions range from 230 to 215 Ma. The associated andesites and dacites are interlayered with slates and sandstones and have ages of around 220 Ma. All of the intrusive and extrusive rocks have similar, highly fractionated REE patterns and high La/Yb (13-49) ratios with no prominent Eu anomalies. They display pronounced negative Nb-Ta and Ti anomalies on primitive mantle-normalized spidergrams. Their SiO2 contents range from 56.6 to 67.1 wt.%, Al2O3 from 14.2 to 17.4 wt.% and MgO from1.9 to 4.2 wt.%. All the rocks have high Sr (258-1980 ppm), and low Y (13-21 ppm) with high Sr/Y ratios (29-102). These features suggest that both the volcanic rocks and porphyritic intrusions were derived from adakitic magmas. They have similar initial 87Sr/86Sr ratios (0.7058 to 0.7077) and εNd (- 1.88 to - 4.93) values, but belong to high silica (HSA) and low silica adakitic rocks (LSA). The HSA represent an early stage of magmatism (230 to 215 Ma) and were derived from oceanic slab melts with limited interaction with the overlying mantle wedge during ascent. At 215 Ma, more extensive interaction produced the LSA. We propose that the early adakitic magmas (HSA) formed by flat subduction leading to melting of oceanic slab, whereas subsequent slab break-off caused the significant interaction between slab melts and the mantle wedge and thus the generation of the later adakitic magmas (LSA).

  6. Geology, petrology, U-Pb (SHRIMP) geochronology of the Morrinhos granite - Paragua terrane, SW Amazonian craton: implications for the magmatic evolution of the San Ignacio orogeny

    Energy Technology Data Exchange (ETDEWEB)

    Franca, Ohana; Ruiz, Amarildo Salina; Sousa, Maria Zelia Aguiar de, E-mail: ohana.geo@gmail.com, E-mail: asruiz@gmail.com, E-mail: mzaguiar@terra.com.br [Universidade Federal de Mato Grosso (UFMT), Cuiaba, MT (Brazil). Instituto de Ciencias Exatas e da Terra. Dept. de Geologia Geral; Batata, Maria Elisa Froes, E-mail: elisabatata@bol.com.br [Universidade Federal de Mato Grosso (UFMT), Cuiaba, MT (Brazil). Grupo de Pesquisa em Evolucao Crustal e Tectonica; Lafon, Jean-Michel [Universidade Federal do Para (GEOCIAM/UFPA), Belem, PR (Brazil). Inst. Nacional de Cencia e Tecnologia de Geociencias da Amazonia

    2014-09-15

    Morrinhos granite is a batholith body that is slightly elongated in the NNW direction and approximately 1,140 km{sup 2} long; it is located in the municipality of Vila Bela da Santissima Trindade of the state of Mato Grosso, Brazil, in the Paragua Terrane, Rondonian-San Ignacio Province, in the SW portion of the Amazonian Craton. This intrusion displays a compositional variation from tonalite to monzogranite, has a medium to coarse inequigranular texture and is locally porphyritic; biotite is the predominant mafic in one of the facies, and hornblende is predominant in the other, with both metamorphosed into the green schist facies. The studied rocks characterize an intermediate to acidic sequence that was formed by a subalkaline magmatism; the series is alkali-calcic to metaluminous to slightly peraluminous, and the rocks evolved through fractioned crystallization mechanisms. The structural data show two deformation phases represented by penetrative foliation (S{sub 1}) and open folds (D{sub 2}), and both phases were most likely related to the San Ignacio Orogeny. The geochronological (U-Pb SHRIMP) and isotopic (Sm-Nd) investigations of these rocks indicated a crystallization age of 1350±12Ma, T{sub DM} of approximately 1.77 Ga and εNd{sub (1.35}) with a negative value of -2.57, suggesting that their generation was related to a partial melting process of a Paleoproterozoic (Statherian) continental crust. The results herein indicate that the Morrinhos granite was generated in a continental magmatic arc in a late- to post-orogenic stage of the San Ignacio Orogeny, and it can be recognized as belonging to the Pensamiento Intrusive Suite. (author)

  7. An implant periapical lesion associated with an endodontic-periodontic lesion of an adjacent molar

    OpenAIRE

    Chou, Ting-An; Chang, Yu-Liang; Yu, Ling-Min; Pan, Whei-Ling; Ju, Yuh-Ren; Chan, Chiu-Po

    2010-01-01

    Adjacent natural teeth with untreated pulpal or periodontal pathology may be a potential risk for implant infection. We report a rare case of an implant periapical lesion (IPL) possibly caused by direct extension of a periradicular lesion of an adjacent tooth. A 40-year-old female patient, who had previously received three implants on the edentulous areas of teeth 16, 36 and 46, had a recurrent infection over the lower left second molar area for 2 years. A periapical radiograph revealed incom...

  8. Local adjacency metric dimension of sun graph and stacked book graph

    Science.gov (United States)

    Yulisda Badri, Alifiah; Darmaji

    2018-03-01

    A graph is a mathematical system consisting of a non-empty set of nodes and a set of empty sides. One of the topics to be studied in graph theory is the metric dimension. Application in the metric dimension is the navigation robot system on a path. Robot moves from one vertex to another vertex in the field by minimizing the errors that occur in translating the instructions (code) obtained from the vertices of that location. To move the robot must give different instructions (code). In order for the robot to move efficiently, the robot must be fast to translate the code of the nodes of the location it passes. so that the location vertex has a minimum distance. However, if the robot must move with the vertex location on a very large field, so the robot can not detect because the distance is too far.[6] In this case, the robot can determine its position by utilizing location vertices based on adjacency. The problem is to find the minimum cardinality of the required location vertex, and where to put, so that the robot can determine its location. The solution to this problem is the dimension of adjacency metric and adjacency metric bases. Rodrguez-Velzquez and Fernau combine the adjacency metric dimensions with local metric dimensions, thus becoming the local adjacency metric dimension. In the local adjacency metric dimension each vertex in the graph may have the same adjacency representation as the terms of the vertices. To obtain the local metric dimension of values in the graph of the Sun and the stacked book graph is used the construction method by considering the representation of each adjacent vertex of the graph.

  9. Analysis of CD83 antigen expression in human breast fibroadenoma and adjacent tissue

    Directory of Open Access Journals (Sweden)

    Marcus Nascimento Borges

    Full Text Available CONTEXT AND OBJECTIVE: Dendritic cell maturation is considered essential for starting an immune response. The CD83 antigen is an important marker of dendritic cell maturation. The objectives here were to analyze CD83 antigen expression in human breast fibroadenoma and breast tissue adjacent to the lesion and to identify clinical factors that might influence this expression. DESIGN AND SETTING: This was a retrospective study at a public university hospital, in which 29 histopathological samples of breast fibroadenoma and adjacent breast tissue, from 28 women of reproductive age, were analyzed. METHODS: The immunohistochemistry method was used to analyze the cell expression of the antigen. The antigen expression in the cells was evaluated by means of random manual counting using an optical microscope. RESULTS: Positive expression of the CD83 antigen in the epithelial cells of the fibroadenoma (365.52; standard deviation ± 133.13 in relation to the adjacent breast tissue cells (189.59; standard deviation ± 140.75 was statistically larger (P < 0.001. Several clinical features were analyzed, but only parity was shown to influence CD83 antigen expression in the adjacent breast tissue, such that positive expression was more evident in nulliparous women (P = 0.042. CONCLUSIONS: The expression of the CD83 antigen in the fibroadenoma was positive and greater than in the adjacent breast tissue. Positive expression of the antigen in the adjacent breast tissue was influenced by parity, and was significantly more evident in nulliparous women.

  10. Risk Factors for the Development of Adjacent Segment Disease Following Anterior Cervical Arthrodesis

    Directory of Open Access Journals (Sweden)

    Ezgi Akar

    2015-06-01

    Full Text Available Aim: The aim of this study was to clinically and radiologically evaluate the efficacy of anterior cervical discectomy and fusion (ACDF in the treatment of adjacent level degeneration. Methods: We retrospectively evaluated 89 patients (55 females, 34 males who underwent ACDF. Adjacent segment degeneration findings were evaluated by investigating new osteophyte formation, growth of existing osteophytes, ossification of the anterior longitudinal ligament, presence of intervertebral disc space narrowing, sagittal alignment and range of motion (ROM using serial radiographs and magnetic resonance imaging. Results: The mean age of the 89 patients was 41.3 (24-76 years. The mean follow-up duration was 34.3 (12-64 months. Radiographic evidence of adjacent segment degeneration was observed in 12 patients (13.4%. Nine (75% patients had new complaints. Of the patients who had degenerative changes, 7 were (58% were male, 5 (42% were female; the mean age was 46 (30- 62 years. It was observed that the level of fusion and the number of fusion did not increase the adjacent segment degeneration. All of 12 patients were observed to have a non lordotic cervical spine and increased ROM. Conclusion: Development of degeneration at the level adjacent to region anterior cervical discectomy and fusion performed is higher compared to non-adjacent levels. The level of fusion and the number of fusion levels have no effect on the development of degeneration. (The Medical Bulletin of Haseki 2015; 53:120-3

  11. Zircon (Hf, O isotopes) as melt indicator: Melt infiltration and abundant new zircon growth within melt rich layers of granulite-facies lenses versus solid-state recrystallization in hosting amphibolite-facies gneisses (central Erzgebirge, Bohemian Massif)

    Science.gov (United States)

    Tichomirowa, Marion; Whitehouse, Martin; Gerdes, Axel; Schulz, Bernhard

    2018-03-01

    In the central Erzgebirge within the Bohemian Massif, lenses of high pressure and ultrahigh pressure felsic granulites occur within meta-sedimentary and meta-igneous amphibolite-facies felsic rocks. In the felsic granulite, melt rich parts and restite form alternating layers, and were identified by petrology and bulk rock geochemistry. Mineral assemblages representing the peak P-T conditions were best preserved in melanocratic restite layers. In contrast, in the melt rich leucocratic layers, garnet and related HP minerals as kyanite are almost completely resorbed. Both layers display differences in accessory minerals: melanosomes have frequent and large monazite and Fe-Ti-minerals but lack xenotime and apatite; leucosomes have abundant apatite and xenotime while monazite is rare. Here we present a detailed petrographic study of zircon grains (abundance, size, morphology, inclusions) in granulite-facies and amphibolite-facies felsic gneisses, along with their oxygen and hafnium isotope compositions. Our data complement earlier Usbnd Pb ages and trace element data (REE, Y, Hf, U) on zircons from the same rocks (Tichomirowa et al., 2005). Our results show that the degree of melting determines the behaviour of zircon in different layers of the granulites and associated amphibolite-facies rocks. In restite layers of the granulite lenses, small, inherited, and resorbed zircon grains are preserved and new zircon formation is very limited. In contrast, new zircons abundantly grew in the melt rich leucocratic layers. In these layers, the new zircons (Usbnd Pb age, trace elements, Hf, O isotopes) best preserve the information on peak metamorphic conditions due to intense corrosion of other metamorphic minerals. The new zircons often contain inherited cores. Compared to cores, the new zircons and rims show similar or slightly lower Hf isotope values, slightly higher Hf model ages, and decreased oxygen isotope ratios. The isotope compositions (Hf, O) of new zircons indicate

  12. Diffusion-Weighted MRI Assessment of Adjacent Disc Degeneration After Thoracolumbar Vertebral Fractures

    Energy Technology Data Exchange (ETDEWEB)

    Noriega, David C., E-mail: dcnoriega1970@gmail.com [Valladolid University Hospital, Spine Department (Spain); Marcia, Stefano, E-mail: stemarcia@gmail.com [SS. Trinità Hospital ASL 8 Cagliari, Department of Radiology (Italy); Ardura, Francisco, E-mail: fardura@ono.com [Valladolid University Hospital, Spine Department (Spain); Lite, Israel Sanchez, E-mail: israelslite@hotmail.com [Valladolid University Hospital, Radiology Department (Spain); Marras, Mariangela, E-mail: mariangela.marrasmd@gmail.com [Azienda Ospedaliero Brotzu (A.O.B.), Department of Radiology (Italy); Saba, Luca, E-mail: lucasaba@tiscali.it [Azienda Ospedaliero Universitaria (A.O.U.), Department of Radiology (Italy)

    2016-09-15

    ObjectiveThe purpose of this study was to assess, by the mean apparent diffusion coefficient (ADC), if a relationship exists between disc ADC and MR findings of adjacent disc degeneration after thoracolumbar fractures treated by anatomic reduction using vertebral augmentation (VAP).Materials and MethodsTwenty non-consecutive patients (mean age 50.7 years; range 45–56) treated because of vertebral fractures, were included in this study. There were 10 A3.1 and 10 A1.2 fractures (AO classification). Surgical treatment using VAP was applied in 14 cases, and conservative in 6 patients. MRI T2-weighted images and mapping of apparent diffusion coefficient (ADC) of the intervertebral disc adjacent to the fractured segment were performed after a mean follow-up of 32 months. A total of 60 discs, 3 per patient, were analysed: infra-adjacent, supra-adjacent and a control disc one level above the supra-adjacent.ResultsNo differences between patients surgically treated and those following a conservative protocol regarding the average ADC values obtained in the 20 control discs analysed were found. Considering all discs, average ADC in the supra-adjacent level was lower than in the infra-adjacent (1.35 ± 0.12 vs. 1.53 ± 0.06; p < 0.001). Average ADC values of the discs used as a control were similar to those of the infra-adjacent level (1.54 ± 0.06). Compared to surgically treated patients, discs at the supra-adjacent fracture level showed statistically significant lower values in cases treated conservatively (p < 0.001). The variation in the delay of surgery had no influence on the average values of ADC at any of the measured levels.ConclusionsADC measurements of the supra-adjacent discs after a mean follow-up of 32 months following thoracolumbar fractures, showed that restoration of the vertebral collapse by minimally invasive VAP prevents posttraumatic disc degeneration.

  13. 33 CFR 148.510 - What happens when a petition for exemption involves the interests of an adjacent coastal State?

    Science.gov (United States)

    2010-07-01

    ... exemption involves the interests of an adjacent coastal State? 148.510 Section 148.510 Navigation and... petition for exemption involves the interests of an adjacent coastal State? If the petition for exemption concerns an adjacent coastal State, the Commandant (CG-5) forwards the petition to the Governor of the...

  14. Sacroiliac Joint Fusion Minimally Affects Adjacent Lumbar Segment Motion: A Finite Element Study.

    Science.gov (United States)

    Lindsey, Derek P; Kiapour, Ali; Yerby, Scott A; Goel, Vijay K

    2015-01-01

    Adjacent segment disease is a recognized consequence of fusion in the spinal column. Fusion of the sacroiliac joint is an effective method of pain reduction. Although effective, the consequences of sacroiliac joint fusion and the potential for adjacent segment disease for the adjacent lumbar spinal levels is unknown. The objective of this study was to quantify the change in range of motion of the sacroiliac joint and the adjacent lumbar spinal motion segments due to sacroiliac joint fusion and compare these changes to previous literature to assess the potential for adjacent segment disease in the lumbar spine. An experimentally validated finite element model of the lumbar spine and pelvis was used to simulate a fusion of the sacroiliac joint using three laterally placed triangular implants (iFuse Implant System, SI-BONE, Inc., San Jose, CA). The range of motion of the sacroiliac joint and the adjacent lumbar spinal motion segments were calculated using a hybrid loading protocol and compared with the intact range of motion in flexion, extension, lateral bending, and axial rotation. The range of motions of the treated sacroiliac joints were reduced in flexion, extension, lateral bending, and axial rotation, by 56.6%, 59.5%, 27.8%, and 53.3%, respectively when compared with the intact condition. The stiffening of the sacroiliac joint resulted in increases at the adjacent lumbar motion segment (L5-S1) for flexion, extension, lateral bending, and axial rotation, of 3.0%, 3.7%, 1.1%, and 4.6%, respectively. Fusion of the sacroiliac joint resulted in substantial (> 50%) reductions in flexion, extension, and axial rotation of the sacroiliac joint with minimal (sacroiliac joint fusion, the long-term clinical results remain to be investigated.

  15. Comment on ;Evolution of high-pressure mafic granulites and pelitic gneisses from NE Madagascar: Tectonic implications;. Tectonophysics, 662, 219-242 (2015) by Ishwar-Kumar et al.

    Science.gov (United States)

    Goncalves, Philippe; Brandt, Sönke; Nicollet, Christian; Tucker, Robert

    2017-05-01

    Determining the possible tectonic regimes active during the Neoproterozoic is crucial for the knowledge of the evolution of the super-continent Gondwana. In Madagascar, that occupies a key position in Gondwana, there is an on-going debate regarding the location of possible suture zones and the implications in terms of paleo-geography. Recognizing high-pressure to ultra-high pressure conditions in mafic rocks is commonly viewed as a strong argument for paleo-subduction zones. Ishwar-Kumar et al. (2015) report unusual high pressure conditions (24 kbar) in Neoproterozoic to Cambrian rocks from North-Central Madagascar (Andriamena Complex). They propose a geodynamic model in which exhumation of the high pressure terranes from up to 80 km to 40 km occurred via vertical extrusion during the collision of various crustal blocks after subduction and closure of an oceanic domain during the formation of Gondwana in the late Neoproterozoic to Cambrian. We question this model and in particular the (ultra-)high pressure conditions reported, because their estimation is based on a misinterpretation of the petrography and inaccurate thermodynamic modeling for the crucial metabasite sample. The authors suggest that garnet-quartz coronas around orthopyroxene and ilmenite coexist with clinopyroxene. The postulated garnet-clinopyroxene-quartz assemblage is interpreted to document an eclogite facies overprint. However, the presence of abundant plagioclase in the sample and the lack of high jadeite content in clinopyroxene clearly refute the postulated eclogite facies conditions. According to the presented photographs clinopyroxene is part of the rock matrix. We therefore suggest that the sample represents a common two-pyroxene granulite, formed at mid- to low-pressure granulite facies conditions of > 700 °C and Madagascar, this interpretation is not justified by the data presented by Ishwar-Kumar et al. (2015).

  16. Geochronology of plutonic rocks and their tectonic terranes in Glacier Bay National Park and Preserve, southeast Alaska: Chapter E in Studies by the U.S. Geological Survey in Alaska, 2008-2009

    Science.gov (United States)

    Brew, David A.; Tellier, Kathleen E.; Lanphere, Marvin A.; Nielsen, Diane C.; Smith, James G.; Sonnevil, Ronald A.

    2014-01-01

    We have identified six major belts and two nonbelt occurrences of plutonic rocks in Glacier Bay National Park and Preserve and characterized them on the basis of geologic mapping, igneous petrology, geochemistry, and isotopic dating. The six plutonic belts and two other occurrences are, from oldest to youngest: (1) Jurassic (201.6–145.5 Ma) diorite and gabbro of the Lituya belt; (2) Late Jurassic (161.0–145.5 Ma) leucotonalite in Johns Hopkins Inlet; (3) Early Cretaceous (145.5–99.6 Ma) granodiorite and tonalite of the Muir-Chichagof belt; (4) Paleocene tonalite in Johns Hopkins Inlet (65.5–55.8 Ma); (5) Eocene granodiorite of the Sanak-Baranof belt; (6) Eocene and Oligocene (55.8–23.0 Ma) granodiorite, quartz diorite, and granite of the Muir-Fairweather felsic-intermediate belt; (7) Eocene and Oligocene (55.8–23.0 Ma) layered gabbros of the Crillon-La Perouse mafic belt; and (8) Oligocene (33.9–23.0 Ma) quartz monzonite and quartz syenite of the Tkope belt. The rocks are further classified into 17 different combination age-compositional units; some younger belts are superimposed on older ones. Almost all these plutonic rocks are related to Cretaceous and Tertiary subduction events. The six major plutonic belts intrude the three southeast Alaska geographic subregions in Glacier Bay National Park and Preserve, from west to east: (1) the Coastal Islands, (2) the Tarr Inlet Suture Zone (which contains the Border Ranges Fault Zone), and (3) the Central Alexander Archipelago. Each subregion includes rocks assigned to one or more tectonic terranes. The various plutonic belts intrude different terranes in different subregions. In general, the Early Cretaceous plutons intrude rocks of the Alexander and Wrangellia terranes in the Central Alexander Archipelago subregion, and the Paleogene plutons intrude rocks of the Chugach, Alexander, and Wrangellia terranes in the Coastal Islands, Tarr Inlet Suture Zone, and Central Alexander Archipelago subregions.

  17. Uplink scheduling and adjacent-channel coupling loss analysis for TD-LTE deployment.

    Science.gov (United States)

    Yeo, Woon-Young; Moon, Sung Ho; Kim, Jae-Hoon

    2014-01-01

    TD-LTE, one of the two duplexing modes in LTE, operates in unpaired spectrum and has the advantages of TDD-based technologies. It is expected that TD-LTE will be more rapidly deployed in near future and most of WiMax operators will upgrade their networks to TD-LTE gradually. Before completely upgrading to TD-LTE, WiMax may coexist with TD-LTE in an adjacent frequency band. In addition, multiple TD-LTE operators may deploy their networks in adjacent bands. When more than one TDD network operates in adjacent frequency bands, severe interference may happen due to adjacent channel interference (ACI) and unsynchronized operations. In this paper, coexistence issues between TD-LTE and other systems are analyzed and coexistence requirements are provided. This paper has three research objectives. First, frame synchronization between TD-LTE and WiMax is discussed by investigating possible combinations of TD-LTE and WiMax configurations. Second, an uplink scheduling algorithm is proposed to utilize a leakage pattern of ACI in synchronized operations. Third, minimum requirements for coexistence in unsynchronized operations are analyzed by introducing a concept of adjacent-channel coupling loss. From the analysis and simulation results, we can see that coexistence of TD-LTE with other TDD systems is feasible if the two networks are synchronized. For the unsynchronized case, some special cell-site engineering techniques may be required to reduce the ACI.

  18. The relative influence of road characteristics and habitat on adjacent lizard populations in arid shrublands

    Science.gov (United States)

    Hubbard, Kaylan A.; Chalfoun, Anna D.; Gerow, Kenneth G.

    2016-01-01

    As road networks continue to expand globally, indirect impacts to adjacent wildlife populations remain largely unknown. Simultaneously, reptile populations are declining worldwide and anthropogenic habitat loss and fragmentation are frequently cited causes. We evaluated the relative influence of three different road characteristics (surface treatment, width, and traffic volume) and habitat features on adjacent populations of Northern Sagebrush Lizards (Sceloporus graciosus graciosus), Plateau Fence Lizards (S. tristichus), and Greater Short-Horned Lizards (Phrynosoma hernandesi) in mixed arid shrubland habitats in southwest Wyoming. Neither odds of lizard presence nor relative abundance was significantly related to any of the assessed road characteristics, although there was a trend for higher Sceloporus spp. abundance adjacent to paved roads. Sceloporus spp. relative abundance did not vary systematically with distance to the nearest road. Rather, both Sceloporus spp. and Greater Short-Horned Lizards were associated strongly with particular habitat characteristics adjacent to roads. Sceloporus spp. presence and relative abundance increased with rock cover, relative abundance was associated positively with shrub cover, and presence was associated negatively with grass cover. Greater Short-Horned Lizard presence increased with bare ground and decreased marginally with shrub cover. Our results suggest that habitat attributes are stronger correlates of lizard presence and relative abundance than individual characteristics of adjacent roads, at least in our system. Therefore, an effective conservation approach for these species may be to consider the landscape through which new roads and their associated development would occur, and the impact that placement could have on fragment size and key habitat elements.

  19. Non-target adjacent stimuli classification improves performance of classical ERP-based brain computer interface

    Science.gov (United States)

    Ceballos, G. A.; Hernández, L. F.

    2015-04-01

    Objective. The classical ERP-based speller, or P300 Speller, is one of the most commonly used paradigms in the field of Brain Computer Interfaces (BCI). Several alterations to the visual stimuli presentation system have been developed to avoid unfavorable effects elicited by adjacent stimuli. However, there has been little, if any, regard to useful information contained in responses to adjacent stimuli about spatial location of target symbols. This paper aims to demonstrate that combining the classification of non-target adjacent stimuli with standard classification (target versus non-target) significantly improves classical ERP-based speller efficiency. Approach. Four SWLDA classifiers were trained and combined with the standard classifier: the lower row, upper row, right column and left column classifiers. This new feature extraction procedure and the classification method were carried out on three open databases: the UAM P300 database (Universidad Autonoma Metropolitana, Mexico), BCI competition II (dataset IIb) and BCI competition III (dataset II). Main results. The inclusion of the classification of non-target adjacent stimuli improves target classification in the classical row/column paradigm. A gain in mean single trial classification of 9.6% and an overall improvement of 25% in simulated spelling speed was achieved. Significance. We have provided further evidence that the ERPs produced by adjacent stimuli present discriminable features, which could provide additional information about the spatial location of intended symbols. This work promotes the searching of information on the peripheral stimulation responses to improve the performance of emerging visual ERP-based spellers.

  20. Analysis of CD83 antigen expression in human breast fibroadenoma and adjacent tissue.

    Science.gov (United States)

    Borges, Marcus Nascimento; Facina, Gil; Silva, Ismael Dale Cotrin Guerreiro; Waitzberg, Angela Flávia Logullo; Nazario, Afonso Celso Pinto

    2011-12-01

    Dendritic cell maturation is considered essential for starting an immune response. The CD83 antigen is an important marker of dendritic cell maturation. The objectives here were to analyze CD83 antigen expression in human breast fibroadenoma and breast tissue adjacent to the lesion and to identify clinical factors that might influence this expression. This was a retrospective study at a public university hospital, in which 29 histopathological samples of breast fibroadenoma and adjacent breast tissue, from 28 women of reproductive age, were analyzed. The immunohistochemistry method was used to analyze the cell expression of the antigen. The antigen expression in the cells was evaluated by means of random manual counting using an optical microscope. Positive expression of the CD83 antigen in the epithelial cells of the fibroadenoma (365.52; standard deviation ± 133.13) in relation to the adjacent breast tissue cells (189.59; standard deviation ± 140.75) was statistically larger (P fibroadenoma was positive and greater than in the adjacent breast tissue. Positive expression of the antigen in the adjacent breast tissue was influenced by parity, and was significantly more evident in nulliparous women.

  1. Gas explosion in a room with a window and passage to an adjacent room

    Directory of Open Access Journals (Sweden)

    Polandov Yuri

    2016-01-01

    Full Text Available Some publications describe an effect, produced during a physical model experiment, when an adjacent gas-free room influences the gas explosion pressure in a room with a window. The explosion pressure in this case significantly exceeds (2.5 times the explosion pressure in a room without an adjacent room. This result has been confirmed by our studies. Based on other available information about the influence of the ignition point location on the explosion pressure in one room, it was suggested that this could be true for an explosion in two rooms. In our studies we used a test unit with two connected chambers, each having a volume of 1.125 m3. It turned out that this influence of the adjacent volume was not so unambiguous as it was described in those publications. It was found out that the maximum effect of explosion pressure amplification by the adjacent room is achieved, when the igniter is located in the chamber filled with a gas-air mixture in the area between the center of the chamber and the window (maximum amplification by more than 3 times. This effect is lower directly by the window (1.8 times and is practically absent in case of ignition within the area near the passage connecting the chamber with the adjacent room. This suggests that the effect discovered earlier is a special case of the general dependence of the gas explosion pressure in two chambers on the igniter location.

  2. Brittle deformation in Southern Granulite Terrane (SGT): A study of pseudotachylyte bearing fractures along Gangavalli Shear Zone (GSZ), Tamil Nadu, India.

    Science.gov (United States)

    mohan Behera, Bhuban; Thirukumaran, Venugopal; Biswal, Tapas kumar

    2016-04-01

    High grade metamorphism and intense deformation have given a well recognition to the Southern Granulite Terrane (SGT) in India. TTG-Charnockite and basic granulites constitute the dominant lithoassociation of the area. Dunite-peridotite-anorthosite-shonkinite and syenites are the intrusives. TTG-charnockite-basic granulite have undergone F1 (isoclinal recumbent), F2 (NE-SW) and F3 (NW-SE) folds producing several interference pattern. E-W trending Neoarchean and Palaeoproterozoic Salem-Attur Shear Zone exhibits a low angle ductile thrust as well as some foot print of late stage brittle deformation near Gangavalli area of Tamil Nadu. The thrust causes exhumation of basic granulites to upper crust. Thrusting along the decollement has retrograded the granulite into amphibolite rock. Subsequently, deformation pattern of Gangavalli area has distinctly marked by numerous vertical to sub-vertical fractures mostly dominating along 0-15 and 270-300 degree within charnockite hills that creates a maximum stress (σ1) along NNW and minimum stress (σ3) along ENE. However, emplacement of pseudotachylyte vein along N-S dominating fracture indicates a post deformational seismic event. Extensive fractures produce anastomose vein with varying thickness from few millimeters to 10 centimeters on the outcrop. ICP-AES study results an isochemical composition of pseudotachylyte vein that derived from the host charnockitic rock where it occurs. But still some noticeable variation in FeO-MgO and Na2O-CaO are obtained from different parts within the single vein showing heterogeneity melt. Electron probe micro analysis of thin sections reveals the existence of melt immiscibility during its solidification. Under dry melting condition, albitic rich melts are considered to be the most favorable composition for microlites (e.g. sheaf and acicular micro crystal) re-crystallization. Especially, acicular microlites preserved tachylite texture that suggest its formation before the final coagulation

  3. New Geochronology and Radiometric Age Dates Improve the Definition and Continuity of Accreted Tectonic Terranes of Northern Venezuela and the Lesser Antilles

    Science.gov (United States)

    Baquero, M.; Mann, P.; Audemard, F. A.

    2017-12-01

    We use new and compiled geochronology and radiometric dates from the area of Venezuela to Tobago to define the following crustal provinces: 1) Guyana shield forms a sub-circular area of Pan-African rocks against which all younger terranes have collided and partially assumed its rounded shape: ages for the Guyana Shield range from >3.4 Ga to 1.8 Ga; 2) accreted Paleozoic rocks form a sub-circular, largely buried province that surround the Guiana Shield to the north and west; the El Pilar strike-slip fault forms the abrupt, northern limit of the Precambrian-Paleozoic craton in Venezuela characterized by crustal thicknesses of 40-50 km; 3) the Early to Late Cretaceous Great Arc of the Caribbean forms a continuous basement high that can be traced from northern Colombia, through the ABC Islands to La Blanquilla Island, and north along the Aves Ridge to the Greater Antilles; ages of the GAC generally are in the range of Late Cretaceous to early Eocene and have geochemistry consistent with intra-oceanic island arcs or oceanic plateau rocks with the exception of La Orchila Island with a Paleozoic intrusive age; the GAC collided from west to east with the passive margin of South America from Paleocene in western Venezuela to Plio-Pleistocene in the Trinidad area and marks the west to east passage of the Caribbean plate past the South American plate; 4) a post-GAC rifting event affected the GAC-South America suture from late Eocene to middle Miocene time in the Falcón Basin of western Venezuela with ages on intrusive and volcanic from 34 to 15.4 Ma; these ages are coeval with intrusive ages from the southernmost Lesser Antilles on Los Frailes and Los Testigos Islands and range from 35.7±2.6 to 36.4±0.5 Ma; the age of the intervening basin, the Bonaire basin, is poorly known but may be coeval with the Oligocene-Miocene extension that extended the suture zone in western Venezuela and extended the Lesser Antilles arc in early Middle Miocene time to form the Lesser Antilles

  4. High resolution crustal structure for the region between the Chilenia and Cuyania terrane above the Pampean flat slab of Argentina from local receiver function and petrological analyses

    Science.gov (United States)

    Ammirati, J. B.; Alvarado, P. M.; Pérez, S. B.; Beck, S. L.; Porter, R. C.; Zandt, G.

    2015-12-01

    Jean-Baptiste Ammirati 1,Sofía Perez 1, Patricia Alvarado 1, Susan L. Beck 2, Ryan Porter 3 and George Zandt 2(1) CIGEOBIO-CONICET, Universidad Nacional de San Juan, Argentina (2) The University of Arizona, USA (3) Northern Arizona University, USA At ~31ºS, The subduction of the Nazca plate under the South American plate presents along-strike variations of its dip angle referred to the Chilean-Pampean flat slab. Geological observations suggest that the regional crustal structure is inherited from the accretion of different terranes at Ordovician times and later reactivated during Andean compression since Miocene. Geophysical observations confirmed that the structure is extending in depth with décollement levels that accommodate crustal shortening in the region. In order to get a better insight on the shallow tectonics we computed high frequency local receiver functions from slab seismicity (~100 km depth). Local earthquakes present a higher frequency content that permits a better vertical resolution. Using a common conversion point (CCP) stacking method we obtained cross sections showing high-resolution crustal structure in the western part of the Pampean flat slab region, at the transition between the Precordillera and the Frontal Cordillera. Our results show a well-defined structure and their lateral extent for both units down to 80 km depth. In good agreement with previous studies, our higher resolution images better identify very shallow discontinuities putting more constraints on the relationships with the regional structural geology. Recent petrological analyses combined with RF high-resolution structure also allow us to better understand the regional crustal composition. Interestingly, we are able to observe a shifting structure beneath the Uspallata-Calingasta Valley, highlighting the differences in terms of crustal structure between the Precordillera and the Frontal Cordillera. Previously determined focal mechanisms in the region match well this

  5. Using remote sensing techniques and field-based structural analysis to explore new gold and associated mineral sites around Al-Hajar mine, Asir terrane, Arabian Shield

    Science.gov (United States)

    Sonbul, Abdullah R.; El-Shafei, Mohamed K.; Bishta, Adel Z.

    2016-05-01

    Modern earth resource satellites provide huge amounts of digital imagery at different resolutions. These satellite imageries are considered one of the most significant sources of data for mineral exploration. Image processing techniques were applied to the exposed rocks around the Al-Aqiq area of the Asir terrane in the southern part of the Arabian Shield. The area under study has two sub-parallel N-S trending metamorphic belts of green-schist facies. The first belt is located southeast of Al-Aqiq, where the Al-Hajar Gold Mine is situated. It is essentially composed of metavolcanics and metasedimentary rocks, and it is intruded by different plutonic rocks of primarily diorite, syenite and porphyritic granite. The second belt is located northwest of Al-Aqiq, and it is composed of metavolcanics and metasedimentary rocks and is intruded by granite bodies. The current study aimed to distinguish the lithological units, detect and map the alteration zones, and extract the major fault lineaments around the Al-Hajar gold prospect. Digital satellite imageries, including Landsat 7 ETM + multispectral and panchromatic and SPOT-5 were used in addition to field verification. Areas with similar spectral signatures to the prospect were identified in the nearby metamorphic belt; it was considered as a target area and was inspected in the field. The relationships between the alteration zones, the mineral deposits and the structural elements were used to locate the ore-bearing zones in the subsurface. The metasedimentary units of the target area showed a dextral-ductile shearing top-to-the-north and the presence of dominant mineralized quartz vein-system. The area to the north of the Al-Hajar prospect showed also sub-parallel shear zones along which different types of alterations were detected. Field-based criteria such as hydrothermal breccia, jasper, iron gossans and porphyritic granite strongly indicate the presence of porphyry-type ore deposits in Al-Hajar metamorphic belt that

  6. Benign Lesions in Mucosa Adjacent to Intestinal-Type Sinonasal Adenocarcinoma

    Directory of Open Access Journals (Sweden)

    Blanca Vivanco

    2011-01-01

    Full Text Available Occupational exposure to wood dust is a strong risk factor for the development of intestinal-type sinonasal adenocarcinoma (ITAC; however, knowledge on possible precursor lesions or biomarkers is limited. Fifty-one samples of tumor-adjacent mucosa and 19 control samples of mucosa from the unaffected fossa of ITAC patients were evaluated for histological changes and p53 protein expression. Mild dysplasia was observed in 14%, cuboidal metaplasia in 57%, intestinal metaplasia in 8%, squamous metaplasia in 24%, and cylindrocellular hyperplasia in 53% of cases. P53 immunopositivity was generally weak occurring most frequently in squamous metaplasia. Wood dust etiology did not appear of influence on the histological changes, but p53 showed a tendency for higher positivity. Dysplasia adjacent to tumor was indicative of subsequent development of recurrence. In conclusion, precursor lesions do occur in mucosa adjacent to ITAC. This is clinically important, because it may justify the screening of high-risk individuals such as woodworkers.

  7. Sound insulation property of membrane-type acoustic metamaterials carrying different masses at adjacent cells

    Science.gov (United States)

    Zhang, Yuguang; Wen, Jihong; Zhao, Honggang; Yu, Dianlong; Cai, Li; Wen, Xisen

    2013-08-01

    We present the experimental realization and theoretical understanding of membrane-type acoustic metamaterials embedded with different masses at adjacent cells, capable of increasing the transmission loss at low frequency. Owing to the reverse vibration of adjacent cells, Transmission loss (TL) peaks appear, and the magnitudes of the TL peaks exceed the predicted results of the composite wall. Compared with commonly used configuration, i.e., all cells carrying with identical mass, the nonuniformity of attaching masses causes another much low TL peak. Finite element analysis was employed to validate and provide insights into the TL behavior of the structure.

  8. TP53 mutations in clinically normal mucosa adjacent to oral carcinomas

    DEFF Research Database (Denmark)

    Thode, Christenze; Bilde, Anders; von Buchwald, Christian

    2010-01-01

    BACKGROUND: The tumour-suppressor protein p53 often accumulates in histologically normal epithelium adjacent to oral squamous cell carcinomas (OSCC). We investigated whether this was associated with mutations in TP53, the gene for p53, and might implicate impending malignancy. METHODS: Specimens...... products were separated by denatured gradient gel electrophoresis. Fragments with a deviant DGEE pattern were sequenced. RESULTS: TP53 mutations were found in six of 18 tumours. Fourteen specimens contained histologically normal mucosa adjacent to the tumour; 13 of these showed small clusters of p53...

  9. Tabu search approaches for the multi-level warehouse layout problem with adjacency constraints

    Science.gov (United States)

    Zhang, G. Q.; Lai, K. K.

    2010-08-01

    A new multi-level warehouse layout problem, the multi-level warehouse layout problem with adjacency constraints (MLWLPAC), is investigated. The same item type is required to be located in adjacent cells, and horizontal and vertical unit travel costs are product dependent. An integer programming model is proposed to formulate the problem, which is NP hard. Along with a cube-per-order index policy based heuristic, the standard tabu search (TS), greedy TS, and dynamic neighbourhood based TS are presented to solve the problem. The computational results show that the proposed approaches can reduce the transportation cost significantly.

  10. The strain-dependent spatial evolution of garnet in a high- P ductile shear zone from the Western Gneiss Region (Norway): a synchrotron X-ray microtomography study

    Energy Technology Data Exchange (ETDEWEB)

    Macente, A. [School of Geosciences, University of Edinburgh, The King' s Building James Hutton Road Edinburgh EH9 3FE UK; Fusseis, F. [School of Geosciences, University of Edinburgh, The King' s Building James Hutton Road Edinburgh EH9 3FE UK; Menegon, L. [School of Geography, Earth and Environmental Sciences, Faculty of Science and Engineering, Plymouth University, Fitzroy Drake Circus Plymouth Devon PL4 8AA UK; Xianghui, X. [Argonne National Laboratory, 9700 S. Cass Ave Building 431-B003 Argonne IL USA; John, T. [Institut für Geologische Wissenschaften, Freie Universität Berlin, Malteserstr. 74-100 12249 Berlin Germany

    2017-03-27

    Reaction and deformation microfabrics provide key information to understand the thermodynamic and kinetic controls of tectono-metamorphic processes, however they are usually analysed in two dimensions, omitting important information regarding the third spatial dimension. We applied synchrotron-based X-ray microtomography to document the evolution of a pristine olivine gabbro into a deformed omphacite-garnet eclogite in four dimensions, where the 4th dimension is represented by the degree of strain. In the investigated samples, which cover a strain gradient into a shear zone from the Western Gneiss Region (Norway), we focused on the spatial transformation of garnet coronas into elongated clusters of garnets with increasing strain. Our microtomographic data allowed quantification of garnet volume, shape and spatial arrangement evolution with increasing strain. We combined microtomographic observations with light microscope- and backscatter electron images as well as electron microprobe- (EMPA) and electron backscatter diffraction (EBSD) analysis to correlate mineral composition and orientation data with the X-ray absorption signal of the same mineral grains. With increasing deformation, the garnet volume almost triples. In the low strain domain, garnets form a well interconnected large garnet aggregate that develops throughout the entire Page 1 of 52 sample. We also observed that garnet coronas in the gabbros never completely encapsulate olivine grains. In the most highly deformed eclogites, the oblate shapes of garnet clusters reflect a deformational origin of the microfabrics. We interpret the aligned garnet aggregates to direct synkinematic fluid flow and consequently influence the transport of dissolved chemical components. EBSD analyses reveal that garnet show a near-random crystal preferred orientation that testifies no evidence for crystal plasticity. There is, however evidence for minor fracturing, neo-nucleation and overgrowth. Microprobe chemical analysis

  11. Origin of the mafic microgranular enclaves (MMEs) and their host granitoids from the Tagong pluton in Songpan-Ganze terrane: An igneous response to the closure of the Paleo-Tethys ocean

    Science.gov (United States)

    Chen, Qiong; Sun, Min; Zhao, Guochun; Yang, Fengli; Long, Xiaoping; Li, Jianhua; Wang, Jun; Yu, Yang

    2017-10-01

    The Songpan-Ganze terrane is mainly composed of a Triassic sedimentary sequence and late Triassic-Jurassic igneous rocks. A large number of plutons were emplaced as a result of tectono-magmatic activity related to the late stages of Paleo-Tethys ocean closure and ensuing collision. Granitoids and their hosted mafic enclaves can provide important constraints on the crust-mantle interaction and continental crustal growth. Mesozoic magmatism of Songpan-Ganze remains enigmatic with regard to their magma generation and geodynamic evolution. The Tagong pluton (209 Ma), in the eastern part of the Songpan-Ganze terrane, consists mainly of monzogranite and granodiorite with abundant coeval mafic microgranular enclaves (MMEs) (ca. 208-209 Ma). The pluton comprises I-type granitoid that possesses intermediate to acidic compositions (SiO2 = 61.6-65.8 wt.%), high potassium (K2O = 3.2-4.1 wt.%), and high Mg# (51-54). They are also characterized by arc-type enrichment of LREEs and LILEs, depletion of HFSEs (e.g. Nb, Ta, Ti) and moderate Eu depletions (Eu/Eu* = 0.46-0.63). Their evolved zircon Hf and whole-rock Nd isotopic compositions indicate that their precursor magmas were likely generated by melting of old lower continental crust. Comparatively, the MMEs have lower SiO2 (53.4-58.2 wt.%), higher Mg# (54-67) and show covariation of major and trace elements, coupled with field and petrographic observations, such as the disequilibrium textures of plagioclase and amphibole, indicating that the MMEs and host granitoids were originated from different magma sources but underwent mafic-felsic magma mixing process. Geochemical and isotopic data further suggest that the precursor magma of the MMEs was formed in the continental arc setting, mainly derived from an ancient metasomatized lithospheric mantle wedge. The Triassic granitoids from the Songpan-Ganze terrane show remarkable temporal-spatial-petrogenetic affinities to the counterparts of subduction zones in the Yidun and Kunlun arc

  12. Recovery act. Characterizing structural controls of EGS-candidate and conventional geothermal reservoirs in the Great Basin. Developing successful exploration strategies in extended terranes

    Energy Technology Data Exchange (ETDEWEB)

    Faulds, James [Univ. of Nevada, Reno, NV (United States)

    2015-06-25

    We conducted a comprehensive analysis of the structural controls of geothermal systems within the Great Basin and adjacent regions. Our main objectives were to: 1) Produce a catalogue of favorable structural environments and models for geothermal systems. 2) Improve site-specific targeting of geothermal resources through detailed studies of representative sites, which included innovative techniques of slip tendency analysis of faults and 3D modeling. 3) Compare and contrast the structural controls and models in different tectonic settings. 4) Synthesize data and develop methodologies for enhancement of exploration strategies for conventional and EGS systems, reduction in the risk of drilling non-productive wells, and selecting the best EGS sites.

  13. Spatiotemporal evolution of Calophaca (Fabaceae) reveals multiple dispersals in the Central Asian mountains and adjacent regions

    Science.gov (United States)

    Ming-Li Zhang; Zhi-Bin Wen; Peter W. Fritsch; Stewart C. Sanderson

    2015-01-01

    The Central Asian flora plays a significant role in Eurasia and the Northern Hemisphere. Calophaca, a member of this flora, includes eight currently recognized species, and is centered in Central Asia, with some taxa extending into adjacent areas. A phylogenetic analysis of the genus utilizing nuclear ribosomal ITS and plastid trnS-trnG and rbcL sequences was carried...

  14. Long-term soil accumulation of chromium, copper, and arsenic adjacent to preservative-treated wood.

    Science.gov (United States)

    S. Lebow; D. Foster; J. Evans

    2004-01-01

    Chromated copper arsenate (CCA) treated wood has been used extensively in outdoor applications. The Environmental Protection Agency (EPA) and CCA producers recently reached an agreement to limit future use of CCA for some types of applications. One area of concern is the long-term accumulation of leached CCA in soil adjacent to treated wood structures. Interpreting...

  15. Testing EGM2008 on Leveling Data from Scandinavia, Adjacent Baltic Areas, and Greenland

    DEFF Research Database (Denmark)

    Strykowski, Gabriel; Forsberg, René

    2010-01-01

    We tested EGM2008 on GPS/leveling data from Scandinavia and adjacent areas. EGM2008 performs at the same level as the best regional geoid model, NKG2004. However, the direct evaluation of EGM2008 is difficult in Greenland because no leveling data are available. Nevertheless, we show on 78 GPS-MSS...

  16. Preliminary assessment of illegal hunting by communities adjacent to the northern Gonarezhou National Park, Zimbabwe

    NARCIS (Netherlands)

    Gandiwa, E.

    2011-01-01

    Illegal hunting of wildlife is a major issue in today’s society, particularly in tropical ecosystems. In this study, a total of 114 local residents from eight villages located in four wards adjacent to the northern Gonarezhou National Park, south-eastern Zimbabwe were interviewed in 2009, using

  17. Regional Spectral Model simulations of the summertime regional climate over Taiwan and adjacent areas

    Science.gov (United States)

    Ching-Teng Lee; Ming-Chin Wu; Shyh-Chin Chen

    2005-01-01

    The National Centers for Environmental Prediction (NCEP) regional spectral model (RSM) version 97 was used to investigate the regional summertime climate over Taiwan and adjacent areas for June-July-August of 1990 through 2000. The simulated sea-level-pressure and wind fields of RSM1 with 50-km grid space are similar to the reanalysis, but the strength of the...

  18. Resonance properties of tidal channels with multiple retention basisn: role of adjacent sea

    NARCIS (Netherlands)

    Roos, Pieter C.; Schuttelaars, H.M.

    2015-01-01

    We present an idealised model of the tidal response in a main channel with multiple secondary basins, co-oscillating with an adjacent sea. The sea is represented as a semi-infinite strip of finite width, anywhere between the limits of a channel extension (narrow) and a half-plane (wide). The sea

  19. Ten-year survival rates of teeth adjacent to treated and untreated posterior bounded edentulous spaces.

    Science.gov (United States)

    Aquilino, S A; Shugars, D A; Bader, J D; White, B A

    2001-05-01

    Failure to replace a single missing posterior tooth may lead to a variety of dental problems, which may ultimately result in tooth loss. However, little is known about the fate of the adjacent teeth if a missing posterior tooth is not replaced. This retrospective study evaluated the survival of teeth adjacent to treated and untreated posterior bounded edentulous spaces. Data were obtained from electronic treatment records from the Kaiser Permanente Dental Care Program, Portland, Ore. A final sample of 317 patients who met the study inclusion criteria was identified. Each bounded edentulous space was placed in 1 of 3 treatment categories: untreated, restored with a fixed partial denture, or restored with a removable partial denture. Subsequent treatment and the status of the teeth adjacent to the bounded edentulous space were followed through December 1999. Ten-year Kaplan-Meier survival estimates were generated for each treatment group, and differences in survival were evaluated with the log-rank chi-square test (alpha=.05). There was a significant difference in survival among the 3 treatment categories (P=.005). Spaces restored with a fixed partial denture had longer 10-year survival estimates (92%) than those that remained untreated (81%). Spaces restored with a removable partial denture had the poorest 10-year survival rate (56%). Under the conditions and selection bias associated with this retrospective study, the survival of teeth adjacent to a single posterior edentulous space was negatively associated with removable partial denture placement compared with no treatment or the use of a fixed partial denture.

  20. Status of fisher in the northern Idaho panhandle and adjacent mountain ranges

    Science.gov (United States)

    Michael Lucid; L. Robinson; S. Cushman; L. Allen; M. Schwartz; K. Pilgrim

    2013-01-01

    The Multi-species Baseline Initiative (MBI) is a collaborative of organizations which is conducting a comprehensive inventory for fisher (Martes pennanti) and other wildlife species across the Idaho Panhandle and adjacent mountain ranges. From 2010-2012, MBI partners established 112 forest carnivore bait stations to collect photographs and DNA from 22 wildlife species...

  1. International comparison calculations for a BWR lattice with adjacent gadolinium pins

    International Nuclear Information System (INIS)

    Maeder, C.; Wydler, P.

    1984-09-01

    The results of burnup calculations for a simplified BWR fuel element with two adjacent gadolinium rods are presented and discussed. Ten complete solutions were contributed by Denmark, France, Italy (3), Japan (3), Switzerland and the UK. Partial results obtained from Poland and the USA are included in an Appendix. (Auth.)

  2. Epigenomic profiling of DNA methylation in paired prostate cancer versus adjacent benign tissue.

    Science.gov (United States)

    Geybels, Milan S; Zhao, Shanshan; Wong, Chao-Jen; Bibikova, Marina; Klotzle, Brandy; Wu, Michael; Ostrander, Elaine A; Fan, Jian-Bing; Feng, Ziding; Stanford, Janet L

    2015-12-01

    Aberrant DNA methylation may promote prostate carcinogenesis. We investigated epigenome-wide DNA methylation profiles in prostate cancer (PCa) compared to adjacent benign tissue to identify differentially methylated CpG sites. The study included paired PCa and adjacent benign tissue samples from 20 radical prostatectomy patients. Epigenetic profiling was done using the Infinium HumanMethylation450 BeadChip. Linear models that accounted for the paired study design and False Discovery Rate Q-values were used to evaluate differential CpG methylation. mRNA expression levels of the genes with the most differentially methylated CpG sites were analyzed. In total, 2,040 differentially methylated CpG sites were identified in PCa versus adjacent benign tissue (Q-value Cancer Genome Atlas (TCGA) data provided confirmatory evidence for our findings. This study of PCa versus adjacent benign tissue showed many differentially methylated CpGs and regions in and outside gene promoter regions, which may potentially be used for the development of future epigenetic-based diagnostic tests or as therapeutic targets. © 2015 Wiley Periodicals, Inc.

  3. Headwater fish population responses to planting grass filter strips adjacent to channelized agricultural headwater streams

    Science.gov (United States)

    Grass filter strips are a widely used conservation practice in the Midwestern United States for reducing nutrient, pesticide, and sediment inputs into agricultural streams. Only a limited amount of information is available on the ecological effects of planting grass filter strips adjacent to channe...

  4. An assessment of transport timescales and return coefficient in adjacent tropical estuaries

    NARCIS (Netherlands)

    Andutta, Fernando P.; Helfer, Fernanda; de Miranda, Luiz Bruner; Deleersnijder, E.L.C.; Thomas, C.J.; Lemckert, Charles

    2016-01-01

    Transport timescales (TTS), namely residence time and exposure time, were computed for adjacent shallow meso-tidal tropical estuarines system using the Lagrangian model D-Waq Part coupled with the hydrodynamic model Delft3D-Flow, and the Constituent-oriented Age and Residence time Theory, CART.

  5. Effects of ecological compensation meadows on arthropod diversity in adjacent intensively managed grassland

    NARCIS (Netherlands)

    Albrecht, M.; Duelli, P.; Obrist, M.K.; Müller, C.; Schüpbach, B.; Kleijn, D.; Schmid, B.

    2010-01-01

    An important goal of ecological compensation areas (ECAs) is to increase biodiversity in adjacent intensively managed farmland and the agricultural landscape at large. We tested whether this goal can be achieved in the case of the agri-environmental restoration scheme implemented for Swiss grassland

  6. Antibacterial Activity of Orthodontic Cement Containing Quaternary Ammonium Polyethylenimine Nanoparticles Adjacent to Orthodontic Brackets

    OpenAIRE

    Eldad Sharon; Revital Sharabi; Adi Eden; Asher Zabrovsky; Gilad Ben-Gal; Esi Sharon; Yoav Pietrokovski; Yael Houri-Haddad; Nurit Beyth

    2018-01-01

    Enamel demineralization is a common problem found in patients using orthodontic devices, such as orthodontic braces. It was found that Streptoccocus mutans growth increases adjacent to orthodontic devices, which may result in caries development. Incorporated antibacterial quaternary ammonium polyethylenimine (QPEI) nanoparticles were previously shown to be highly efficacious against various bacteria. Combining antibacterial materials in orthodontic cement may be advantageous to prevent bacter...

  7. Low-loss hollow-core silica fibers with adjacent nested anti-resonant tubes

    DEFF Research Database (Denmark)

    Habib, Selim; Bang, Ole; Bache, Morten

    2015-01-01

    We report on numerical design optimization of hollow-core antiresonant fibers with the aim of reducing transmission losses. We show that re-arranging the nested anti-resonant tubes in the cladding to be adjacent has the effect of significantly reducing leakage as well as bending losses, and for r...

  8. Edge effects of stink bugs in corn, cotton, peanut and soybean fields adjacent to woodland.

    Science.gov (United States)

    Producers face significant crop losses from stink bug species in the southeastern USA, but the high mobility and polyphagy of the bugs make predictions of their presence in crops difficult. While there is some evidence that they colonize crops from adjacent crops, there are no studies of their colo...

  9. Post-frontier forest change adjacent to Braulio Carrillo National Park, Costa Rica

    Science.gov (United States)

    John Schelhas; G. Arturo Sanchez-Azofeifa

    2006-01-01

    Effective biodiversity conservation in national parks depends to a large extent on adjacent forest cover. While deforestation and forest fragmentation as a result of colonization and agriculture have been widespread in neotropical countries over the past few decades, in some places agricultural intensification, wage labor, and rural to urban migration are becoming the...

  10. Histological and histomorphometrical evaluation of tissue reactions adjacent to endosteal implants in monkeys

    DEFF Research Database (Denmark)

    Gotfredsen, K; Rostrup, E; Hjörting-Hansen, E

    1992-01-01

    A qualitative and quantitative histological study of the initial healing response adjacent to 24 submerged and non-submerged implants placed in the lower jaws of 6 monkeys is presented. The histomorphometric analysis showed no significant differences in mineralized bone-implant contact length...

  11. Examining incentives for adjacent non-industrial private forest landowners to cooperate

    Science.gov (United States)

    Melinda Vokoun; Gregory S Amacher; Jay Sullivan; Dave Wear

    2010-01-01

    Individual landowners may capture non-timber benefits from both their own forested parcels and adjacent parcels owned by different landowners. These benefits may affect incentives for landowners to cooperate in their forest management decisions. Landowner survey data is used to examine incentives to cooperate concerning joint forest management and coordination of...

  12. Deformations and damage to buildings adjacent to deep excavations in soft soils

    NARCIS (Netherlands)

    Korff, M.

    2009-01-01

    The objective of this study is to gain insight into mechanisms of soil-structure interaction for buildings adjacent to deep excavations and to find a reliable method to design and monitor deep excavations in urban areas with soft soil conditions. The research focuses on typical Dutch conditions. The

  13. Non-Adjacent Dependency Learning in Infants at Familial Risk of Dyslexia

    Science.gov (United States)

    Kerkhoff, Annemarie; de Bree, Elise; de Klerk, Maartje; Wijnen, Frank

    2013-01-01

    This study tests the hypothesis that developmental dyslexia is (partly) caused by a deficit in implicit sequential learning, by investigating whether infants at familial risk of dyslexia can track non-adjacent dependencies in an artificial language. An implicit learning deficit would hinder detection of such dependencies, which mark grammatical…

  14. Adjacency-blurring-effect of scenes modeled by the radiosity method

    Energy Technology Data Exchange (ETDEWEB)

    Borel, C.C.; Gerstl, S.A.W.

    1992-05-01

    In this paper we describe a method to simulate images through a scattering atmosphere. We compute the scattering of light from adjacent surfaces into the field-of-view (FOV) with the extended radiosity method. Our simulation takes aerosol scattering phase functions and ground bidirectional reflectance distributions (BRDF) into account. 10 refs.

  15. Tourist preferences for ecotourism in rural communities adjacent to Kruger National Park: A choice experiment approach

    NARCIS (Netherlands)

    Chaminuka, P.; Groeneveld, R.A.; Selomane, A.O.; Ierland, van E.C.

    2012-01-01

    This paper analyses the potential for development of ecotourism in rural communities adjacent to Kruger National Park (KNP) in South Africa. We determine preferences of tourists, according to origin and income levels, for ecotourism and their marginal willingness to pay (MWTP) for three ecotourism

  16. 77 FR 53164 - Railroad Workplace Safety; Adjacent-Track On-Track Safety for Roadway Workers

    Science.gov (United States)

    2012-08-31

    ...-0059, Notice No. 6] RIN 2130-AC37 Railroad Workplace Safety; Adjacent-Track On-Track Safety for Roadway... complex issues raised in both the petitions for reconsideration of the final rule published November 30... issues. One of the Petitions included a request for a delay in the effective date of the final rule until...

  17. 78 FR 33754 - Railroad Workplace Safety; Adjacent-Track On-Track Safety for Roadway Workers

    Science.gov (United States)

    2013-06-05

    ...-0059, Notice No. 7] RIN 2130-AC37 Railroad Workplace Safety; Adjacent-Track On-Track Safety for Roadway... and comments raised a number of substantive issues requiring a detailed response. As FRA's response to... INFORMATION: On November 30, 2011, FRA published a final rule amending its regulations on railroad workplace...

  18. 77 FR 13978 - Railroad Workplace Safety; Adjacent-Track On-Track Safety for Roadway Workers

    Science.gov (United States)

    2012-03-08

    ...-0059, Notice No. 5] RIN 2130-AB96 Railroad Workplace Safety; Adjacent-Track On-Track Safety for Roadway... that raise a number of substantive issues requiring a detailed response. Accordingly, in order to...: On November 30, 2011, FRA published a final rule amending its regulations on railroad workplace...

  19. 27 CFR 19.241 - Operations bond-distilled spirits plant and adjacent bonded wine cellar.

    Science.gov (United States)

    2010-04-01

    ... spirits plant and adjacent bonded wine cellar. 19.241 Section 19.241 Alcohol, Tobacco Products and... wine cellar. (a) General. A wine cellar under the provisions of 27 CFR part 24 shall be treated as... subpart G for the production of distilled spirits; and (2) Such wine cellar and distilled spirits plant...

  20. Impacted maxillary canines and root resorption of adjacent teeth: A retrospective observational study.

    Science.gov (United States)

    Guarnieri, R; Cavallini, C; Vernucci, R; Vichi, M; Leonardi, R; Barbato, E

    2016-11-01

    The prevalence of impacted maxillary canine is reported to be between 1% and 3%. The lack of monitoring and the delay in the treatment of the impacted canine can cause different complications such as: displacement of adjacent teeth, loss of vitality of neighbouring teeth, shortening of the dental arch, follicular cysts, canine ankylosis, recurrent infections, recurrent pain, internal resorption of the canine and the adjacent teeth, external resorption of the canine and the adjacent teeth, combination of these factors. An appropriate diagnosis, accurate predictive analysis and early intervention are likely to prevent such undesirable effects. The objective is to evaluate, by means of a retrospective observational study, the possibility of carrying out a predictive analysis of root resorption adjacent to the impacted canines by means of orthopantomographs, so as to limit the prescription of additional 3D radiography. 120 subjects with unilateral or bilateral maxillary impacted canine were examined and 50 patients with 69 impacted maxillary canine (22 male, 28 female; mean age: 11.7 years) satisfied the inclusion criteria of the study. These patients were subjected to a basic clinical and radiographic investigation (orthopantomographs and computerized tomography). All panoramic films were viewed under standardized conditions for the evaluation of two main variables: maxillary canine angulations (a, b, g angles) and the overlapping between the impacted teeth and the lateral incisor (Analysis of Lindauer). Binary logistic regression was used to estimate the likelihood of resorbed lateral incisors depending on sector location and angle measurements. Results indicated that b angle has the greatest influence on the prediction of root resorption (predictive value of b angle = 76%). If β angle <18° and Lindauer = I, the probability of resorption is 0.06. Evaluation of b angle and superimposition lateral incisor/impacted canine analysed on orthopantomographs could be one of

  1. Survival of the Lhasa Terrane during its collision with Asia due to crust-mantle coupling revealed by ca. 114 Ma intrusive rocks in western Tibet

    Science.gov (United States)

    Wang, Qing; Zhu, Di-Cheng; Liu, An-Lin; Cawood, Peter A.; Liu, Sheng-Ao; Xia, Ying; Chen, Yue; Wang, Hao; Zhang, Liang-Liang; Zhao, Zhi-Dan

    2018-04-01

    Survival of the Lhasa Terrane during its drift across the Tethyan Ocean and subsequent collision with Asia was likely maintained by mechanical coupling between its ancient lithospheric mantle and the overlying crust. Evidence for this coupling is provided by geochronological and geochemical data from high-Mg dioritic porphyrite dikes that intruded into granodiorites with dioritic enclaves within the Nixiong Batholith in the western segment of the central Lhasa subterrane, southern Tibet. Zircon LA-ICP-MS U-Pb dating indicates synchronous emplacement of dioritic porphyrite dikes (113.9 ± 2 Ma), dioritic enclaves (113.9 ± 1 Ma), and host granodiorites (113.1 ± 2 Ma). The hornblende-bearing granodiorites are metaluminous to weakly peraluminous (A/CNK = 0.95-1.05) and belong to high-K calc-alkaline I-type granite. These rocks are characterized by low Mg# (37-43), negative zircon εHf(t) values (-6.8 to -1.2), and negative whole-rock εNd(t) values (-8.1 to -5.4), suggestive of derivation through anatexis of ancient lower crust. The two least-mixed or contaminated dioritic porphyrite dike samples have high MgO (8.46-8.74 wt%), high Mg# (69-70), and high abundances of compatible elements (e.g., Cr = 673-646 ppm, Ni = 177-189 ppm), which are close to those of primitive magma. They are high-K calc-alkaline and show negative whole-rock εNd(t) values (-1.9 to -1.2), indicating that these samples are most likely derived from the partial melting of ancient lithospheric mantle that was metasomatized by slab-derived fluids. The dioritic enclave samples are metaluminous high-K calc-alkaline and have varying negative whole-rock εNd(t) values (-7.8 to -3.7), which are interpreted as the result of magma mixing between the ancient lower crust-derived melts and asthenospheric mantle- (rather than lithospheric mantle-) derived melts. The Nd isotope mantle model ages of the least-mixed or contaminated high-Mg dioritic porphyrite dike samples (1.1-1.4 Ga) are close to the Nd isotope

  2. Cryogenian alkaline magmatism in the Southern Granulite Terrane, India: Petrology, geochemistry, zircon U-Pb ages and Lu-Hf isotopes

    Science.gov (United States)

    Santosh, M.; Yang, Qiong-Yan; Ram Mohan, M.; Tsunogae, T.; Shaji, E.; Satyanarayanan, M.

    2014-11-01

    The Southern Granulite Terrane (SGT) in India preserves the records of the formation and recycling of continental crust from Mesoarchean through Paleoproterozoic to Neoproterozoic and Cambrian, involving multiple subduction-accretion-collision associated with major orogenic cycles. A chain of unmetamorphosed and undeformed alkaline magmatic intrusions occurs along the northern margin of the SGT aligned along paleo-suture zones. Here we investigate two representative plutons from this suite, the Angadimogar syenite (AM) and the Peralimala alkali granite (PM) through field, petrological, geochemical, zircon U-Pb and Lu-Hf studies. Magma mixing and mingling textures and mineral assemblages typical of alkaline rocks are displayed by these plutons. The whole-rock major and trace element data characterize their alkaline nature. In trace element discrimination diagrams, the AM rocks straddle between the VAG (volcanic-arc granites) and WPG (within plate granites) fields with most of the samples confined to the VAG field, whereas the PM rocks are essentially confined to the WPG field. The diversity in some of the geochemical features between the two plutons is interpreted to be the reflection of source heterogeneities. Most zircon grains from the AM and PM plutons display oscillatory zoning typical of magmatic crystallization although some grains, particularly those from the PM pluton, show core-rim structures with dark patchy zoned cores surrounded by irregular thin rims resulting from fluid alteration. The weighted mean 206Pb/238U ages of the magmatic zircons from three samples of the AM syenite are in the range of 781.8 ± 3.8 Ma to 798 ± 3.6 Ma and those from two samples of the PM alkali granite yield ages of 797.5 ± 3.7 Ma and 799 ± 6.2 Ma. A mafic magmatic enclave from the AM pluton shows weighted mean 206Pb/238U age of 795 ± 3.3 Ma. The AM and PM plutons also carry rare xeneocrystic zircons which define upper intercept concordia ages of 3293 ± 13 Ma and 2530

  3. Paleomagnetic constraints on early collisional deformation along the eastern margin of the Qiantang terrane (Tibetan plateau) at 50 and 37 Ma.

    Science.gov (United States)

    Roperch, Pierrick; Dupont-Nivet, Guillaume; Guillot, Stéphane; Goussin, Fanny; Huang, Wentao; Replumaz, Anne; Yang, Zhang; Guo, Zhaojie; Song, Bowen

    2017-04-01

    Ongoing controversies on the timing and latitude of the India-Asia collision with associated formation of the Tibetan plateau have major implications on geodynamic, climatic and biotic models. Rock paleomagnetic inclinations and declinations enable in principle to quantify respectively paleolatitudes and tectonic rotations. However, shallow paleomagnetic inclinations observed for most of the Cenozoic rocks across the active belts of Central Asia have been controversially interpreted as resulting from non dipolar geomagnetic fields, inclination flattening in the sedimentary data or large scale continental deformation. In addition tectonic rotations from the Eastern margin of Tibet may result from extrusion or dextral shear associated with implication on the early collision. We present new paleomagnetic results from two Cenozoic basins of the Eastern part of the Qiantang block characterized by two short-lived volcanic fields at 37-38Ma (Nangqian area) and 49-51Ma (Xialaxiu area). In the Xialaxiu area, we sampled the volcanic field near the town of Xialaxiu and red beds filling the Sangalaxiu basin 10 to 20km farther north. Results from the red beds after tilt correction (D=328.3°, I=34.3°, α95=7.6°) confirm the result (D=322.0°, I=32.3°, α95=9.5°) previously obtained by Cogne et al., (1999) but the age and nature of the characteristic magnetization are uncertain. The mean direction calculated from 21 sites in volcanic rocks provides a more reliable paleofield (D=11.9°, I=41.6°, α95=8.0°). Comparison with the expected direction for stable Eurasia suggest no rotation but significant post 50 Ma shortening north of the Qiantang block in agreement with results from the Lhasa terrane at the same age (56-47 Ma) (van Hinsbergen et al., 2012). In the Nangqian basin, paleomagnetic sites have been collected in red beds sediments, sills and dikes intruding the red bed sequence and in extrusive volcanic rocks mainly found on top of the sedimentary sequence. A well

  4. Recycling of Amazonian detrital zircons in the Mixteco terrane, southern Mexico: Paleogeographic implications during Jurassic-Early Cretaceous and Paleogene times

    Science.gov (United States)

    Silva-Romo, Gilberto; Mendoza-Rosales, Claudia Cristina; Campos-Madrigal, Emiliano; Morales-Yáñez, Axél; de la Torre-González, Alam Israel; Nápoles-Valenzuela, Juan Ivan

    2018-04-01

    In the northeastern Mixteco terrane of southern Mexico, in the Ixcaquixtla-Atzumba region, the recycling of Amazonian detrital zircons records the paleogeography during the Mesozoic period in the context of the breakup of Pangea, a phenomenon that disarticulated the Sanozama-La Mora paleo-river. The clastic units of southern Mexico in the Ayuquila, Otlaltepec and Zapotitlán Mesozoic basins, as well as in the Atzumba Cenozoic basin, are characterized by detrital zircon contents with ages specific to the Amazonian craton, ranging between 3040 and 1278 Ma. The presence of zircons of Amazonian affinity suggests a provenance by recycling from carrier units such as the La Mora Formation or the Ayú Complex. In the area, the Ayú and Acatlán complexes form the Cosoltepec block, a paleogeographic element that during Early Cretaceous time acted as the divide between the slopes of the paleo-Gulf of Mexico and the paleo-Pacific Ocean. The sedimentological characteristics of the Jurassic-Cenozoic clastic successions in the Ixcaquixtla-Atzumba region denote relatively short transport in braided fluvial systems and alluvial fans. In this way, several basins are recognized around the Cosoltepec block. At the southeastern edge of the Cosoltepec block, the Ayuquila and Tecomazúchil formations accumulated in the Ayuquila continental basin on the paleo-Pacific Ocean slope. On the other hand, within the paleo-Gulf of Mexico slope, in the Otlaltepec continental basin, the Piedra Hueca and the Otlaltepec formations accumulated. The upper member of the Santa Lucía Formation accumulated in a transitional environment on the southwestern shoulder of the Zapotitlán basin, as well as on the paleo-Gulf of Mexico slope. In the Ayuquila basin, a marine transgression is recognized that advanced from south to north during the Late Jurassic. At the northeastern edge of the Cosoltepec block, we propose that the Santa Lucía formation attests to a transgression from the paleo-Gulf of Mexico

  5. On the Adjacent Strong Equitable Edge Coloring of Pn ∨ Pn, Pn ∨ Cn and Cn ∨ Cn

    OpenAIRE

    Liu Jun; Zhao Chuan Cheng; Yao Shu Xia; Guo Ren Zhi; Yue Qiu Ju

    2016-01-01

    A proper edge coloring of graph G is called equitable adjacent strong edge coloring if colored sets from every two adjacent vertices incident edge are different,and the number of edges in any two color classes differ by at most one,which the required minimum number of colors is called the adjacent strong equitable edge chromatic number. In this paper, we discuss the adjacent strong equitable edge coloring of join-graphs about Pn ∨ Pn, Pn ∨ Cn and Cn ∨ Cn.

  6. Pelvic incidence-lumbar lordosis mismatch predisposes to adjacent segment disease after lumbar spinal fusion.

    Science.gov (United States)

    Rothenfluh, Dominique A; Mueller, Daniel A; Rothenfluh, Esin; Min, Kan

    2015-06-01

    Several risk factors and causes of adjacent segment disease have been debated; however, no quantitative relationship to spino-pelvic parameters has been established so far. A retrospective case-control study was carried out to investigate spino-pelvic alignment in patients with adjacent segment disease compared to a control group. 45 patients (ASDis) were identified that underwent revision surgery for adjacent segment disease after on average 49 months (7-125), 39 patients were selected as control group (CTRL) similar in the distribution of the matching variables, such as age, gender, preoperative degenerative changes, and numbers of segments fused with a mean follow-up of 84 months (61-142) (total n = 84). Several radiographic parameters were measured on pre- and postoperative radiographs, including lumbar lordosis measured (LL), sacral slope, pelvic incidence (PI), and tilt. Significant differences between ASDis and CTRL groups on preoperative radiographs were seen for PI (60.9 ± 10.0° vs. 51.7 ± 10.4°, p = 0.001) and LL (48.1 ± 12.5° vs. 53.8 ± 10.8°, p = 0.012). Pelvic incidence was put into relation to lumbar lordosis by calculating the difference between pelvic incidence and lumbar lordosis (∆PILL = PI-LL, ASDis 12.5 ± 16.7° vs. CTRL 3.4 ± 12.1°, p = 0.001). A cutoff value of 9.8° was determined by logistic regression and ROC analysis and patients classified into a type A (∆PILL lordosis mismatch. In type A spino-pelvic alignment, 25.5 % of patients underwent revision surgery for adjacent segment disease, whereas 78.3 % of patients classified as type B alignment had revision surgery. Classification of patients into type A and B alignments yields a sensitivity for predicting adjacent segment disease of 71 %, a specificity of 81 % and an odds ratio of 10.6. In degenerative disease of the lumbar spine a high pelvic incidence with diminished lumbar lordosis seems to predispose to adjacent segment disease. Patients with such pelvic incidence

  7. Treatment of Osteomyelitis: A Case for Disruption of the Affected Adjacent Periosteum.

    Science.gov (United States)

    Hudson, John W; Daly, Austin P; Foster, Michael

    2017-10-01

    To evaluate the response of mandibular osteomyelitis treated by surgical decortication with disruption of the affected adjacent periosteum in concert with long-term targeted antibiotic therapy. The hypothesis is that, by removing the buccal cortical plate and disrupting the hypertrophically inflamed adjacent periosteum, the medullary bone will be brought in contact with bleeding tissue and circulating immunologic factors and antibiotics, which will promote definitive resolution. A retrospective review was conducted of 7 patient charts with associated radiographs from November 2010 to August 2016 treated by the first author at the University of Tennessee Medical Center (Knoxville, TN). Patients with chronic suppurative or nonsuppurative osteomyelitis of the mandible without condylar involvement or pathologic fracture were selected and treated with decortication with periosteal disruption in combination with long-term targeted antibiotic therapy. Seven patients (3 women and 4 men; mean age, 60 yr) underwent decortication with periosteal disruption of the affected area and received at least 6 weeks of targeted intravenous antibiotics. Computed tomography was performed preoperatively and a repeat study was performed after completion of antibiotics. In each case, post-treatment imaging showed definitive resolution after treatment with decortication in concert with disruption of the inflamed hypertrophic periosteum and intravenous antibiotics. Debridement of the infected cortical bone with restoration of the blood supply through disruption of the adjacent periosteum provided definitive resolution of mandibular osteomyelitis in the 7 patients treated. The hypothesis is that disruption of the affected adjacent periosteum reintroduces an immune-mediated response in concert with improved antibiotic delivery to and penetrance of the diseased mandible, aiding in definitive resolution. Decortication with periosteal disruption allows for preservation of the inferior alveolar

  8. Field characteristics, petrography, and geochronology of the Hohonu Batholith and the adjacent Granite Hill Complex, North Westland, New Zealand

    International Nuclear Information System (INIS)

    Waight, T.E.; Weaver, S.D.; Ireland, T.R.; Maas, R.; Muir, R.J.; Shelley, D.

    1997-01-01

    Detailed geological mapping, petrography, geochemistry and geochronological studies in the Hohonu Batholith, North Westland, have identified 10 granitoid plutons emplaced during three intrusive episodes. The earliest episode is represented by a single dated Paleozoic pluton, Summit Granite (new) (381.2 ± 7.3 Ma), which is correlated with a discrete pulse of Mid-Late Devonian plutonism recognised in the Karamea Batholith. The undated Mount Graham Granite (new) is also likely to be Paleozoic, based on chemical and petrographic characteristics. The bulk of the batholith (seven plutons) was emplaced in the mid Cretaceous (114-109 Ma) and comprises two related, yet distinct, geochemical suites, which correlate with the previously defined Rahu Suite. The plutons identified are (from north to south): Pah Point Granite; Jays Creek Granodiorite (new); Uncle Bay Tonalite; Te Kinga Monzogranite; Deutgam Granodiorite; Turiwhate Granodiorite (new); and Arahura Granite (new). Mid-Cretaceous plutonism in the Western Province is considered to be the result of crustal thinning and extension following overthickening during collision of the Early Cretaceous Median Tectonic Zone volcanic arc. Late Cretaceous alkaline activity is represented by the emplacement of the A-type French Creek Granite at 1.7 ± 1.8 Ma, contemporaneous with intrusion of a major swarm of doleritic-lamprophyric dikes - the Hohonu Dike Swarm. These events correlate with the first appearance of oceanic crust in the Tasman Sea. The Granite Hill Complex is a suite of amphibolite facies gneisses occurring as an uplifted wedge between the Alpine Fault nd the Hohonu Batholith. These gneisses are considered to represent an extension of the Fraser Complex to the south. A detailed understanding of their geological affinities and history is yet to be established. (author). 66 refs., 7 figs., 3 tabs

  9. Structural, petrological and geochronological analysis of the lithotypes from the Pien region (Parana State, Brazil) and adjacences

    International Nuclear Information System (INIS)

    Harara, Ossama Mohamed

    1996-01-01

    The Pien area presents the major geotectonic domains separated by the Pien Shear Zone (PSZ). The northern one is the Rio Pien Granite-Mylonitic Suite composed by calc-alkaline granitoids of Neoproterozoic age. The southern domain is represented by the Amphibolite-Granulite where high grade metamorphism took place at the end of paleoproterozoic time. Considering the identified lithotypes, their geochemical affinity (particularly the Ti, Cr, Ni and REE content) and the geological context observed in the area, a geotectonical model of active continental margin related to subduction SSZ (Supra-Subduction Zone) is proposed. K-Ar on plagioclase from gabbronorites gave Neoproterozoic ages although Sm-Nd whole rock isochron yielded Paleoproterozoic ages. Based in geochemical data, it is proposed that the biotite gneiss and biotite-amphibole-gneiss which occur near the PSZ have a shoshonitic to high-K calc-alkaline features which are characteristic of active continental margins. K-Ar on biotite extracted from these rocks, gave Neoproterozoic ages. The available radiometric data for the Rio Pien mylonitic granitoids show that between 650-595 Ma the generation, deformation and cooling below the isotherm of 250 deg C occurred. On the other hand, the geochronological data for the Agudos do Sul Massif are in the 590-570 Ma interval showing its younger generation. The Sr 87 / Sr 86 initial ratios for both granitoids suggest more involvement of the continental crust in the origins of Agudos do Sul granitic Massif. The analyses of the entire set of the available data for the Pien area allows the suggestion of a geotectonic scenery related to the evolution of an active continental margin during the collages associated to the Brasiliano Cycle

  10. A Voronoi interior adjacency-based approach for generating a contour tree

    Science.gov (United States)

    Chen, Jun; Qiao, Chaofei; Zhao, Renliang

    2004-05-01

    A contour tree is a good graphical tool for representing the spatial relations of contour lines and has found many applications in map generalization, map annotation, terrain analysis, etc. A new approach for generating contour trees by introducing a Voronoi-based interior adjacency set concept is proposed in this paper. The immediate interior adjacency set is employed to identify all of the children contours of each contour without contour elevations. It has advantages over existing methods such as the point-in-polygon method and the region growing-based method. This new approach can be used for spatial data mining and knowledge discovering, such as the automatic extraction of terrain features and construction of multi-resolution digital elevation model.

  11. Maxillary second molar impaction in the adjacent ectopic third molar: Report of five rare cases

    Science.gov (United States)

    Souki, Bernardo Q.; Cheib, Paula L.; de Brito, Gabriela M.; Pinto, Larissa S. M. C.

    2015-01-01

    Maxillary second molar impaction in the adjacent ectopic third molar is a rare condition that practitioners might face in the field of pediatric dentistry and orthodontics. The early diagnosis and extraction of the adjacent ectopic third molar have been advocated, and prior research has reported a high rate of spontaneous eruption following third molar removal. However, some challenges in the daily practice are that the early diagnosis of this type of tooth impaction is difficult with conventional radiographic examination, and sometimes the early surgical removal of the maxillary third molar must be postponed because of the risks of damaging the second molar. The objective of this study is to report a case series of five young patients with maxillary second molar impaction and to discuss the difficulty of early diagnosis with the conventional radiographic examination, and unpredictability of self-correction. PMID:26321848

  12. Flexible Connection Elastomeric Rubber as a Pounding Resisting Element between Two Adjacent Buildings

    Directory of Open Access Journals (Sweden)

    Yuskar Lase

    2013-03-01

    Full Text Available To solve pounding problem of two adjacent buildings, structural designer usually employs a dilatation between the structures or make the two structures as a monolith structure. Other alternative is by using an elastomeric rubber as a pounding resisting element between the two structures. Effectiveness in applying elastomeric rubber component as flexible connection of two adjacent structures is the main focus of this paper. Various simulations such as structure models, earthquake excitations and openings in gap element are studied. Observation of maximum structural responses will be performed for structure model with elastomeric rubber in comparison with (1 monolith structure model and (2 structure model with rigid element (steel element. Simulation results show that application of elastomeric rubber component to prevent structures from pounding problem provides advantages especially in reducing internal forces in the shorter building. However, it slightly increases displacement of both structures.

  13. Maxillary second molar impaction in the adjacent ectopic third molar: Report of five rare cases

    Directory of Open Access Journals (Sweden)

    Bernardo Q Souki

    2015-01-01

    Full Text Available Maxillary second molar impaction in the adjacent ectopic third molar is a rare condition that practitioners might face in the field of pediatric dentistry and orthodontics. The early diagnosis and extraction of the adjacent ectopic third molar have been advocated, and prior research has reported a high rate of spontaneous eruption following third molar removal. However, some challenges in the daily practice are that the early diagnosis of this type of tooth impaction is difficult with conventional radiographic examination, and sometimes the early surgical removal of the maxillary third molar must be postponed because of the risks of damaging the second molar. The objective of this study is to report a case series of five young patients with maxillary second molar impaction and to discuss the difficulty of early diagnosis with the conventional radiographic examination, and unpredictability of self-correction.

  14. The dynamics of innovation through the expansion in the adjacent possible

    International Nuclear Information System (INIS)

    Tria, F.

    2016-01-01

    The experience of something new is part of our daily life. At different scales, innovation is also a crucial feature of many biological, technological and social systems. Recently, large databases witnessing human activities allowed the observation that novelties —such as the individual process of listening a song for the first time— and innovation processes —such as the fixation of new genes in a population of bacteria— share striking statistical regularities. We here indicate the expansion into the adjacent possible as a very general and powerful mechanism able to explain such regularities. Further, we will identify statistical signatures of the presence of the expansion into the adjacent possible in the analyzed datasets, and we will show that our modeling scheme is able to predict remarkably well these observations.

  15. A programmable DNA origami nanospring that reveals force-induced adjacent binding of myosin VI heads.

    Science.gov (United States)

    Iwaki, M; Wickham, S F; Ikezaki, K; Yanagida, T; Shih, W M

    2016-12-12

    Mechanosensitive biological nanomachines such as motor proteins and ion channels regulate diverse cellular behaviour. Combined optical trapping with single-molecule fluorescence imaging provides a powerful methodology to clearly characterize the mechanoresponse, structural dynamics and stability of such nanomachines. However, this system requires complicated experimental geometry, preparation and optics, and is limited by low data-acquisition efficiency. Here we develop a programmable DNA origami nanospring that overcomes these issues. We apply our nanospring to human myosin VI, a mechanosensory motor protein, and demonstrate nanometre-precision single-molecule fluorescence imaging of the individual motor domains (heads) under force. We observe force-induced transitions of myosin VI heads from non-adjacent to adjacent binding, which correspond to adapted roles for low-load and high-load transport, respectively. Our technique extends single-molecule studies under force and clarifies the effect of force on biological processes.

  16. Microemulsions as model fluids for enhanced oil recovery: dynamics adjacent to planar hydrophilic walls

    Directory of Open Access Journals (Sweden)

    Mattauch S.

    2012-10-01

    Full Text Available After the dynamics of microemulsions adjacent to a planar hydrophilic wall have been characterized using grazing incidence neutron spin echo spectroscopy, the model of Seifert was employed to explain the discovered acceleration for the surface near lamellar ordered membranes. Reflections of hydrodynamic waves by the wall – or the volume conservation between the membrane and the wall – explain faster relaxations and, therefore, a lubrication effect that is important for flow fields in narrow pores. The whole scenery is now spectated by using different scenarios of a bicontinuous microemulsion exposed to clay particles and of a lamellar microemulsion adjacent to a planar wall. The Seifert concept could successfully be transferred to the new problems.

  17. Genetic organization of the unc-22 IV gene and the adjacent region in Caenorhabditis elegans.

    Science.gov (United States)

    Rogalski, T M; Baillie, D L

    1985-01-01

    The genetic organization of the region immediately adjacent to the unc-22 IV gene in Caenorhabditis elegans has been studied. We have identified twenty essential genes in this interval of approximately 1.5-map units on Linkage Group IV. The mutations that define these genes were positioned by recombination mapping and complementation with several deficiencies. With few exceptions, the positions obtained by these two methods agreed. Eight of the twenty essential genes identified are represented by more than one allele. Three possible internal deletions of the unc-22 gene have been located by intra-genic mapping. In addition, the right end point of a deficiency or an inversion affecting the adjacent genes let-56 and unc-22 has been positioned inside the unc-22 gene.

  18. The Impact of a Shopping Centre on the Value of Adjacent Residential Properties

    OpenAIRE

    M. C. Sale

    2015-01-01

    One of the most significant changes in the South African retail landscape over the past few decades is the increase in the number and size of retail shopping centres situated in, or close to, residential areas. These shopping centres have the potential to generate both positive and negative externalities which may, in turn, be capitalised into adjacent residential property prices. However, policy makers are still unsure as to the effect of commercial land uses such as shopping centres on surr...

  19. Core-adjacent instrumentation systems for pebble bed reactors for process heat application - state of planning

    International Nuclear Information System (INIS)

    Benninghofen, G.; Serafin, N.; Spillekothen, H.G.; Hecker, R.; Brixy, H.; Serpekian, T.

    1982-06-01

    Planning and theoretical/experimental development work for core surveillance instrumentation systems is being performed to meet requirements of pebble bed reactors for process heat application. Detailed and proved instrumentation concepts are now available for the core-adjacent instrumentation systems. The current work and the results of neutron flux measurements at high temperatures are described. Operation devices for long-term accurate gas outlet temperature measurements up to approximately 1423 deg. K will also be discussed. (author)

  20. An implant periapical lesion associated with an endodontic-periodontic lesion of an adjacent molar

    Directory of Open Access Journals (Sweden)

    Ting-An Chou

    2010-09-01

    Full Text Available Adjacent natural teeth with untreated pulpal or periodontal pathology may be a potential risk for implant infection. We report a rare case of an implant periapical lesion (IPL possibly caused by direct extension of a periradicular lesion of an adjacent tooth. A 40-year-old female patient, who had previously received three implants on the edentulous areas of teeth 16, 36 and 46, had a recurrent infection over the lower left second molar area for 2 years. A periapical radiograph revealed incomplete root canal treatment and an infrabony defect on the mesial side of the lower left second molar; the defect extended to the apical third of the adjacent implant on tooth 36. Open flap debridement was performed 1 year after implant placement, but pain and swelling persisted for another year. Therefore, the second molar was extracted at the patient's request. The patient was unable to seek earlier and prompt treatment as she was abroad; therefore, we were able to observe the progression of severity in the IPL. One year after the extraction, the symptoms had subsided, and a periapical radiograph showed that the radiolucent lesion had decreased in size. She was followed for another 1.5 years and showed marked improvement. In this case, the IPL probably originated from the endodontic-periodontic problem of the adjacent molar, and the infected implant was saved by removing the infection source. We also discuss the treatment and prognosis of IPLs. To prevent the occurrence of an IPL, it is important to evaluate the pulpal and periodontal status of the teeth near the implant site when making a comprehensive treatment plan for an implant.

  1. World cup soccer players tend to be born with sun and moon in adjacent zodiacal signs

    Science.gov (United States)

    Verhulst, J

    2000-01-01

    The ecliptic elongation of the moon with respect to the sun does not show uniform distribution on the birth dates of the 704 soccer players selected for the 1998 World Cup. However, a uniform distribution is expected on astronomical grounds. The World Cup players show a very pronounced tendency (p = 0.00001) to be born on days when the sun and moon are in adjacent zodiacal signs. Key Words: soccer; World Cup; astrology; moon PMID:11131239

  2. Risk factors for adjacent segment degeneration after surgical correction of degenerative lumbar scoliosis

    Directory of Open Access Journals (Sweden)

    Kee-yong Ha

    2013-01-01

    Full Text Available Background: Degenerative lumbar scoliosis surgery can lead to development of adjacent segment degeneration (ASD after lumbar or thoracolumbar fusion. Its incidence, risk factors, morbidity and correlation between radiological and clinical symptoms of ASD have no consensus. We evaluated the correlation between the occurrence of radiologic adjacent segment disease and certain imperative parameters. Materials and Methods: 98 patients who had undergone surgical correction and lumbar/thoracolumbar fusion with pedicle screw instrumentation for degenerative lumbar scoliosis with a minimum 5 year followup were included in the study. We evaluated the correlation between the occurrence of radiologic adjacent segment disease and imperative patient parameters like age at operation, sex, body mass index (BMI, medical comorbidities and bone mineral density (BMD. The radiological parameters taken into consideration were Cobb′s angle, angle type, lumbar lordosis, pelvic incidence, intercristal line, preoperative existence of an ASD on plain radiograph and magnetic resonance imaging (MRI and surgical parameters were number of the fusion level, decompression level, floating OP (interlumbar fusion excluding L5-S1 level and posterolateral lumbar interbody fusion (PLIF. Clinical outcomes were assessed with the Visual Analogue Score (VAS and Oswestry Disability Index (ODI. Results: ASD was present in 44 (44.9% patients at an average period of 48.0 months (range 6-98 months. Factors related to occurrence of ASD were preoperative existence of disc degeneration (as revealed by MRI and age at operation ( P = 0.0001, 0.0364. There were no statistically significant differences between radiological adjacent segment degeneration and clinical results (VAS, P = 0.446; ODI, P = 0.531. Conclusions: Patients over the age of 65 years and with preoperative disc degeneration (as revealed by plain radiograph and MRI were at a higher risk of developing ASD.

  3. Finite element analysis of skirted foundation adjacent to sand slope under earthquake loading

    OpenAIRE

    Azzam, W.R.

    2015-01-01

    This paper reports the application of using a skirted foundation system to study the behavior of foundations with structural skirts adjacent to a sand slope and subjected to earthquake loading. The effect of the adopted skirts to safeguard foundation and slope from collapse is studied. The skirts effect on controlling horizontal soil movement and decreasing pore water pressure beneath foundations and beside the slopes during earthquake is investigated. This technique is investigated numerical...

  4. IMMEDIATE RECIPROCAL CHANGES AT ADJACENT LEVEL FOLLOWING SINGLE-LEVEL ALIF

    OpenAIRE

    Uribe, Enrique Vargas; Amaral, Rodrigo; Marchi, Luis; Jensen, Rubens; Oliveira, Leonardo; Fortti, Fernanda; Coutinho, Etevaldo; Pimenta, Luiz

    2015-01-01

    Objective : To assess the segmental sagittal parameters and the adjacent mobile segment after interbody fusion by anterior approach in single-level L5-S1. Methods : Retrospective study. Inclusion: Interbody fusion by anterior approach (10°/15° angle), due to DDD, low-grade spondylolisthesis and/or stenosis without prior lumbar fusion. Thirty-five cases were included (25 women; mean age 47±15 years). Analysis of lumbar radiographs were performed preoperatively and 3 months after surgery. The ...

  5. Environmental Settings and Harmful Algal Blooms in the Sea Area Adjacent to the Changjiang River Estuary

    OpenAIRE

    Zhou, Mingjiang

    2010-01-01

    The characteristics of the environmental settings of the sea area adjacent to the Changjiang River estuary include complex currents and water masses, the diluted water plume and its redirection, upwelling, front, and nutrients and their sources. The Changjiang River estuary characteristics also include the phytoplankton community, which can affect the growth, migration, assembling, resting and competition of algae to form red tides in this area.. The features of red tide events recorded in th...

  6. Experimental study on brain injury in Beagle dogs caused by adjacent cabin explosion in warship

    Directory of Open Access Journals (Sweden)

    Yan-teng LI

    2017-04-01

    Full Text Available Objective  Through the establishment of adjacent cabin blast injury model of Beagle dog, to investigate the pathophysiological changes in the experimental animals in this scenario, then speculate on the mechanisms of injury. Methods  Several adjacent cabins were built in the same size with the real warship. Seven Beagle dogs were subjected to injuries from the explosion, from whom one was selected randomly to implant intracranial pressure transducers before blast, the others were tested on the pathophysiological changes after blast. The dogs were mounted on the platform of a cabinet in the adjacent cabin, subjected to injury from 650g bare TNT explosive blast. The transducers recorded the value of space and intracranial shock wave pressure. Following blast treatment, the serum levels of IL -6, IL -8, neuron specific enolase (NSE, brain and chest CT and pathological changes of the brain tissue were observed. Results  Serum levels of IL-6, IL-8 and NSE were elevated to varying degrees after blast. All of them increased significantly at different time points after blast (P<0.05. Brain and chest CT examinations did not show any significant positive results. Pathological results showed that there was a little necrosis in the brain, some neurons had karyopycnosis, karyolysis or disappearance of the nucleoli, and the cell boundaries were blurred. The blast wave was blocked greatly by the scalp and skull (about 90%, but could still penetrate them and cause brain injuries. Conclusions  Explosion in the adjacent cabin causes mainly mild traumatic brain injuries. Blast wave can be blocked by the scalp and skull greatly. DOI: 10.11855/j.issn.0577-7402.2017.03.11

  7. Ground-water resources in the tri-state region adjacent to the Lower Delaware River

    Science.gov (United States)

    Barksdale, Henry C.; Greenman, David W.; Lang, Solomon Max; Hilton, George Stockbridge; Outlaw, Donald E.

    1958-01-01

    The purpose of this report is to appraise and evaluate the groundwater resources of a tri-state region adjacent to the lower Delaware River that is centered around Philadelphia, Pa., and Camden, N. J., and includes Wilmington, Del., and Trenton, N.J. Specifically, the region includes New Castle County, Del.; Burlington, Camden, Gloucester, Mercer, and Salem Counties in New Jersey; and Bucks, Chester, Delaware, Montgomery, and Philadelphia Counties in Pennsylvania.

  8. Ossificans myositis: inflammatory changes and contrast enhancement of adjacent bone shown by MR imaging

    International Nuclear Information System (INIS)

    David, H.; Jolles, E.; Le Friant, G.; Silvestre, A.; Sarrazin, J.L.; Gordoliani, Y.S.

    1995-01-01

    The authors report a case of ossificans myositis, in which magnetic resonance imaging (MRI) showed inflammatory changes of the adjacent bone. T 1 weighted fat saturation sequence with gadolinium injection showed enhancement of medullary and cortical bone. This potentially mistaking pattern must be known, to avoid mis diagnosing with malignant osseous tumor, specially before achievement of the characteristic pattern of zonal maturation and its calcified rim. (authors). 15 refs., 6 figs

  9. Deer use of riparian zones and adjacent pine plantations in Texas

    Science.gov (United States)

    Micah L. Poteet; Ronald E. Thill; R. Montague Whiting; R. Lee Rayburn

    1996-01-01

    The authors monitored white-tailed deer (Odocoileus virginianus) use of riparian zones (RZ’s) and adjacent pine plantations of 3 age classes (young, 1 to 3 years old; intermediate, 5 to 7 years old; and older, 9 to 13 years old) using radio telemetry for 2 years on a 1,300 ha study area near Alto, TX. Riparian zones comprised 22.0 percent of the area; young,...

  10. Relevance of adjacent joint imaging in the evaluation of ankle fractures.

    Science.gov (United States)

    Antoci, Valentin; Patel, Shaun P; Weaver, Michael J; Kwon, John Y

    2016-10-01

    Routinely obtaining adjacent joint radiographs when evaluating patients with ankle fractures may be of limited clinical utility and an unnecessary burden, particularly in the absence of clinical suspicion for concomitant injuries. One thousand, three hundred and seventy patients who sustained ankle fractures over a 5-year period presenting to two level 1 trauma centers were identified. Medical records were retrospectively reviewed for demographics, physical examination findings, and radiographic information. Analyses included descriptive statistics along with sensitivity and predictive value calculations for the presence of adjacent joint fracture. Adjacent joint imaging (n=1045 radiographs) of either the knee or foot was obtained in 873 patients (63.7%). Of those, 75/761 patients (9.9%) demonstrated additional fractures proximal to the ankle joint, most commonly of the proximal fibula. Twenty-two of 284 (7.7%) demonstrated additional fractures distal to the ankle joint, most commonly of the metatarsals. Tenderness to palpation demonstrated sensitivities of 0.92 and 0.77 and positive predictive values of 0.94 and 0.89 for the presence of proximal and distal fractures, respectively. Additionally, 19/22 (86.4%) of patients sustaining foot fractures had their injury detectable on initial ankle X-rays. Overall, only 5.5% (75/1370) of patients sustained fractures proximal to the ankle and only 0.2% (3/1370) of patients had additional foot fractures not evident on initial ankle X-rays. The addition of adjacent joint imaging for the evaluation of patients sustaining ankle fractures is low yield. As such, patient history, physical examination, and clinical suspicion should direct the need for additional X-rays. Level IV. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Successive Two-sided Loop Jets Caused by Magnetic Reconnection between Two Adjacent Filamentary Threads

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Zhanjun; Liu, Yu; Shen, Yuandeng [Yunnan Observatories, Chinese Academy of Sciences, Kunming, 650216 (China); Elmhamdi, Abouazza; Kordi, Ayman S. [Department of Physics and Astronomy, King Saud University, P.O. Box 2455, 11451 (Saudi Arabia); Su, Jiangtao [University of Chinese Academy of Sciences, Beijing 100049 (China); Liu, Ying D., E-mail: ydshen@ynao.ac.cn [State Key Laboratory of Space Weather, Chinese Academy of Sciences, Beijing 100190 (China)

    2017-08-20

    We present observational analysis of two successive two-sided loop jets observed by the ground-based New Vacuum Solar Telescope and the space-borne Solar Dynamics Observatory . The two successive two-sided loop jets manifested similar evolution processes and both were associated with the interaction of two small-scale adjacent filamentary threads, magnetic emerging, and cancellation processes at the jet’s source region. High temporal and high spatial resolution observations reveal that the two adjacent ends of the two filamentary threads are rooted in opposite magnetic polarities within the source region. The two threads approached each other, and then an obvious brightening patch is observed at the interaction position. Subsequently, a pair of hot plasma ejections are observed heading in opposite directions along the paths of the two filamentary threads at a typical speed for two-sided loop jets of the order 150 km s{sup −1}. Close to the end of the second jet, we report the formation of a bright hot loop structure at the source region, which suggests the formation of new loops during the interaction. Based on the observational results, we propose that the observed two-sided loop jets are caused by magnetic reconnection between the two adjacent filamentary threads, largely different from the previous scenario that a two-sided loop jet is generated by magnetic reconnection between an emerging bipole and the overlying horizontal magnetic fields.

  12. Bacterial community composition in Brazilian Anthrosols and adjacent soils characterized using culturing and molecular identification.

    Science.gov (United States)

    O'Neill, B; Grossman, J; Tsai, M T; Gomes, J E; Lehmann, J; Peterson, J; Neves, E; Thies, J E

    2009-07-01

    Microbial community composition was examined in two soil types, Anthrosols and adjacent soils, sampled from three locations in the Brazilian Amazon. The Anthrosols, also known as Amazonian dark earths, are highly fertile soils that are a legacy of pre-Columbian settlement. Both Anthrosols and adjacent soils are derived from the same parent material and subject to the same environmental conditions, including rainfall and temperature; however, the Anthrosols contain high levels of charcoal-like black carbon from which they derive their dark color. The Anthrosols typically have higher cation exchange capacity, higher pH, and higher phosphorus and calcium contents. We used culture media prepared from soil extracts to isolate bacteria unique to the two soil types and then sequenced their 16S rRNA genes to determine their phylogenetic placement. Higher numbers of culturable bacteria, by over two orders of magnitude at the deepest sampling depths, were counted in the Anthrosols. Sequences of bacteria isolated on soil extract media yielded five possible new bacterial families. Also, a higher number of families in the bacteria were represented by isolates from the deeper soil depths in the Anthrosols. Higher bacterial populations and a greater diversity of isolates were found in all of the Anthrosols, to a depth of up to 1 m, compared to adjacent soils located within 50-500 m of their associated Anthrosols. Compared to standard culture media, soil extract media revealed diverse soil microbial populations adapted to the unique biochemistry and physiological ecology of these Anthrosols.

  13. PROSPECTIVE STUDY OF HISTOLOGICAL PROLIFERATIVE CHANGES IN ADJACENT AREAS OF BREAST CANCER

    Directory of Open Access Journals (Sweden)

    Rema Nair Sarkar

    2016-11-01

    Full Text Available BACKGROUND Breast cancer remains a global health problem with an increasing incidence. Proliferative breast diseases are recognised as one of the risk factors in the development of carcinoma. This study was undertaken to know the frequency of proliferative lesions and other lesions in association with breast carcinomas in mastectomy specimens. MATERIALS AND METHODS 100 cases of excised carcinoma breast sent to the Department of Pathology for a three-year period at tertiary care centre was thoroughly examined and changes adjacent to the tumour was recorded and tissue was subjected for histopathological examination and results tabulated. RESULTS Infiltrating duct cell carcinoma, Not Otherwise Specified (NOS type was present in 89% of cases. Among the associated lesions, nonproliferative lesions constituted 16%, proliferative breast disease without atypia 29%, proliferative breast disease with atypia 10% and others 45%. Fibrocystic disease constituted 14% of cases, epithelial hyperplasia 15%, sclerosing adenosis 12% and atypical ductal hyperplasia in 10% of cases. Other types of associated lesions were duct carcinoma in situ in 4 cases. CONCLUSION Proliferative lesions adjacent to carcinoma breast were seen in 39% of cases. Fibrocystic disease, epithelial hyperplasia, sclerosing adenosis and atypical ductal hyperplasia being the commonest lesions adjacent to carcinoma breast in the present study.

  14. Interaction between two adjacent grounded sources in frequency domain semi-airborne electromagnetic survey.

    Science.gov (United States)

    Zhou, Haigen; Lin, Jun; Liu, Changsheng; Kang, Lili; Li, Gang; Zeng, Xinsen

    2016-03-01

    Multi-source and multi-frequency emission method can make full use of the valuable and short flight time in frequency domain semi-airborne electromagnetic (FSAEM) exploration, which has potential to investigate the deep earth structure in complex terrain region. Because several sources are adjacent in multi-source emission method, the interaction of different sources should be considered carefully. An equivalent circuit model of dual-source is established in this paper to assess the interaction between two individual sources, where the parameters are given with the typical values based on the practical instrument system and its application. By simulating the output current of two sources in different cases, the influence from the adjacent source is observed clearly. The current waveforms show that the mutual resistance causes the fluctuation and drift in another source and that the mutual inductance causes transient peaks. A field test with dual-source was conducted to certify the existence of interaction between adjacent sources. The simulation of output current also shows that current errors at low frequency are mainly caused by the mutual resistance while those at high frequency are mainly due to the mutual inductance. Increasing the distance between neighboring sources is a proposed measure to reduce the emission signal errors with designed ones. The feasible distance is discussed in the end. This study gives a useful guidance to lay multi sources to meet the requirement of measurement accuracy in FSAEM survey.

  15. Late Permian to Triassic intraplate orogeny of the southern Tianshan and adjacent regions, NW China

    Directory of Open Access Journals (Sweden)

    Wei Ju

    2014-01-01

    Based on previous studies and recent geochronogical data, we suggest that the final collision between the Tarim Craton and the North Asian continent occurred during the late Carboniferous. Therefore, the Permian was a period of intracontinental environment in the southern Tianshan and adjacent regions. We propose that an earlier, small-scale intraplate orogenic stage occurred in late Permian to Triassic time, which was the first intraplate process in the South Tianshan Orogen and adjacent regions. The later large-scale and well-known Neogene to Quaternary intraplate orogeny was induced by the collision between the India subcontinent and the Eurasian plate. The paper presents a new evolutionary model for the South Tianshan Orogen and adjacent regions, which includes seven stages: (I late Ordovician–early Silurian opening of the South Tianshan Ocean; (II middle Silurian–middle Devonian subduction of the South Tianshan Ocean beneath an active margin of the North Asian continent; (III late Devonian–late Carboniferous closure of the South Tianshan Ocean and collision between the Kazakhstan-Yili and Tarim continental blocks; (IV early Permian post-collisional magmatism and rifting; (V late Permian–Triassic the first intraplate orogeny; (VI Jurassic–Palaeogene tectonic stagnation and (VII Neocene–Quaternary intraplate orogeny.

  16. Correction of thickness measurement errors for two adjacent sheet structures in MR images

    International Nuclear Information System (INIS)

    Cheng Yuanzhi; Wang Shuguo; Sato, Yoshinobu; Nishii, Takashi; Tamura, Shinichi

    2007-01-01

    We present a new method for measuring the thickness of two adjacent sheet structures in MR images. In the hip joint, in which the femoral and acetabular cartilages are adjacent to each other, a conventional measurement technique based on the second derivative zero crossings (called the zero-crossings method) can introduce large underestimation errors in measurements of cartilage thickness. In this study, we have developed a model-based approach for accurate thickness measurement. We model the imaging process for two adjacent sheet structures, which simulate the two articular cartilages in the hip joint. This model can be used to predict the shape of the intensity profile along the sheet normal orientation. Using an optimization technique, the model parameters are adjusted to minimize the differences between the predicted intensity profile and the actual intensity profiles observed in the MR data. The set of model parameters that minimize the difference between the model and the MR data yield the thickness estimation. Using three phantoms and one normal cadaveric specimen, the usefulness of the new model-based method is demonstrated by comparing the model-based results with the results generated using the zero-crossings method. (author)

  17. Differential transcriptional profiling of damaged and intact adjacent dorsal root ganglia neurons in neuropathic pain.

    Directory of Open Access Journals (Sweden)

    A K Reinhold

    Full Text Available Neuropathic pain, caused by a lesion in the somatosensory system, is a severely impairing mostly chronic disease. While its underlying molecular mechanisms are not thoroughly understood, neuroimmune interactions as well as changes in the pain pathway such as sensitization of nociceptors have been implicated. It has been shown that not only are different cell types involved in generation and maintenance of neuropathic pain, like neurons, immune and glial cells, but, also, intact adjacent neurons are relevant to the process. Here, we describe an experimental approach to discriminate damaged from intact adjacent neurons in the same dorsal root ganglion (DRG using differential fluorescent neuronal labelling and fluorescence-activated cell sorting (FACS. Two fluorescent tracers, Fluoroemerald (FE and 1-dioctadecyl-3,3,3,3-tetramethylindocarbocyanine perchlorate (DiI, were used, whose properties allow us to distinguish between damaged and intact neurons. Subsequent sorting permitted transcriptional analysis of both groups. Results and qPCR validation show a strong regulation in damaged neurons versus contralateral controls as well as a moderate regulation in adjacent neurons. Data for damaged neurons reveal an mRNA expression pattern consistent with established upregulated genes like galanin, which supports our approach. Moreover, novel genes were found strongly regulated such as corticotropin-releasing hormone (CRH, providing novel targets for further research. Differential fluorescent neuronal labelling and sorting allows for a clear distinction between primarily damaged neuropathic neurons and "bystanders," thereby facilitating a more detailed understanding of their respective roles in neuropathic processes in the DRG.

  18. fMRI Evidence of Acupoints Specificity in Two Adjacent Acupoints

    Directory of Open Access Journals (Sweden)

    Hua Liu

    2013-01-01

    Full Text Available Objectives. Acupoint specificity is the foundation of acupuncture treatment. The aim of this study is to investigate whether the acupoint specificity exists in two adjacent acupoints. Design and Setting. Two adjacent real acupoints, LR3 (Taichong and ST44 (Neiting, and a nearby nonacupoint were selected. Thirty-three health volunteers were divided into three groups in random order, and each group only received acupuncture at one of the three points. While they received acupuncture, fMRI scan was performed. Results. The common cerebral activated areas responding to LR3 and ST44 included the contralateral primary somatosensory area (SI and ipsilateral cerebellum. Acupuncture at LR3 specifically activated contralateral middle occipital gyrus, ipsilateral medial frontal gyrus, superior parietal lobe, middle temporal gyrus, rostral anterior cingulate cortex (rACC, lentiform nucleus, insula, and contralateral thalamus. Stimulation at ST44 selectively activated ipsilateral secondary somatosensory area (SII, contralateral middle frontal gyrus, inferior frontal gyrus, lingual gyrus, lentiform nucleus, and bilateral posterior cingulate cortex (PCC. Conclusions. Acupuncture at adjacent acupoints elicits distinct cerebral activation patterns, and those specific patterns might be involved in the mechanism of the specific therapeutic effects of different acupoints.

  19. Matrix intensification alters avian functional group composition in adjacent rainforest fragments.

    Directory of Open Access Journals (Sweden)

    Justus P Deikumah

    Full Text Available Conversion of farmland land-use matrices to surface mining is an increasing threat to the habitat quality of forest remnants and their constituent biota, with consequences for ecosystem functionality. We evaluated the effects of matrix type on bird community composition and the abundance and evenness within avian functional groups in south-west Ghana. We hypothesized that surface mining near remnants may result in a shift in functional composition of avifaunal communities, potentially disrupting ecological processes within tropical forest ecosystems. Matrix intensification and proximity to the remnant edge strongly influenced the abundance of members of several functional guilds. Obligate frugivores, strict terrestrial insectivores, lower and upper strata birds, and insect gleaners were most negatively affected by adjacent mining matrices, suggesting certain ecosystem processes such as seed dispersal may be disrupted by landscape change in this region. Evenness of these functional guilds was also lower in remnants adjacent to surface mining, regardless of the distance from remnant edge, with the exception of strict terrestrial insectivores. These shifts suggest matrix intensification can influence avian functional group composition and related ecosystem-level processes in adjacent forest remnants. The management of matrix habitat quality near and within mine concessions is important for improving efforts to preserveavian biodiversity in landscapes undergoing intensification such as through increased surface mining.

  20. Antibacterial Activity of Orthodontic Cement Containing Quaternary Ammonium Polyethylenimine Nanoparticles Adjacent to Orthodontic Brackets.

    Science.gov (United States)

    Sharon, Eldad; Sharabi, Revital; Eden, Adi; Zabrovsky, Asher; Ben-Gal, Gilad; Sharon, Esi; Pietrokovski, Yoav; Houri-Haddad, Yael; Beyth, Nurit

    2018-03-27

    Enamel demineralization is a common problem found in patients using orthodontic devices, such as orthodontic braces. It was found that Streptoccocus mutans growth increases adjacent to orthodontic devices, which may result in caries development. Incorporated antibacterial quaternary ammonium polyethylenimine (QPEI) nanoparticles were previously shown to be highly efficacious against various bacteria. Combining antibacterial materials in orthodontic cement may be advantageous to prevent bacterial outgrowth adjacent to orthodontic brackets. The aim was to evaluate the efficiency of orthodontic cement containing QPEI nanoparticles in reducing S. mutans and Lactobacillus casei outgrowth adjacent to orthodontic brackets. Orthodontic brackets were bonded to the buccal surfaces of extracted lower incisors. The antibacterial effect on S. mutans and L. casei outgrowth of Neobond bracket adhesive orthodontic cement with and without QPEI nanoparticles was compared. The antibacterial effect was evaluated using crystal violet staining and bacterial count (CFU/mL). The teeth in the experimental group, with the QPEI nanoparticles cement, showed significantly lower optical density (OD) values and CFU counts of S. mutans and L. casei than the teeth in the control group ( p brackets.

  1. Dlx proteins position the neural plate border and determine adjacent cell fates.

    Science.gov (United States)

    Woda, Juliana M; Pastagia, Julie; Mercola, Mark; Artinger, Kristin Bruk

    2003-01-01

    The lateral border of the neural plate is a major source of signals that induce primary neurons, neural crest cells and cranial placodes as well as provide patterning cues to mesodermal structures such as somites and heart. Whereas secreted BMP, FGF and Wnt proteins influence the differentiation of neural and non-neural ectoderm, we show here that members of the Dlx family of transcription factors position the border between neural and non-neural ectoderm and are required for the specification of adjacent cell fates. Inhibition of endogenous Dlx activity in Xenopus embryos with an EnR-Dlx homeodomain fusion protein expands the neural plate into non-neural ectoderm tissue whereas ectopic activation of Dlx target genes inhibits neural plate differentiation. Importantly, the stereotypic pattern of border cell fates in the adjacent ectoderm is re-established only under conditions where the expanded neural plate abuts Dlx-positive non-neural ectoderm. Experiments in which presumptive neural plate was grafted to ventral ectoderm reiterate induction of neural crest and placodal lineages and also demonstrate that Dlx activity is required in non-neural ectoderm for the production of signals needed for induction of these cells. We propose that Dlx proteins regulate intercellular signaling across the interface between neural and non-neural ectoderm that is critical for inducing and patterning adjacent cell fates.

  2. Growth and decline of shoreline industry in Sydney estuary (Australia) and influence on adjacent estuarine sediments.

    Science.gov (United States)

    Birch, G F; Lean, J; Gunns, T

    2015-06-01

    Sydney estuary (Australia), like many urbanised waterways, is degraded due to an extended history of anthropogenic activity. Two major sources of contamination to this estuary are discharge by former shoreline industries and historic and contemporary catchment stormwater. The objectives of the present study were to document changes in shoreline land use from European settlement to the present day and determine the influence of this trend on the metal content of adjacent estuarine sediments. Temporal analysis of land use for seven time horizons between 1788 and 2010 showed rapid expansion of industry along much of the Sydney estuary foreshore soon after European settlement due to the benefits of easy and inexpensive access and readily available water for cooling and power. Shoreline industry attained maximum development in 1978 (32-km length) and declined rapidly to the present-day (9-km length) through redevelopment of industrial sites into medium- to high-density, high-value residential housing. Cores taken adjacent to 11 long-term industrial sites showed that past industrial practices contributed significantly to contamination of estuarine sediment. Subsurface metal concentrations were up to 35 times that of present-day surface sediment and over 100 times greater than natural background concentrations. Sedimentation rates for areas adjacent to shoreline industry were between 0.6 and 2.5 cm/year, and relaxation times were estimated at 50 to 100 years. Natural relaxation and non-disturbance of sediments may be the best management practice in most locations.

  3. 33 CFR 334.85 - New York Harbor, adjacent to the Stapleton Naval Station, Staten Island, New York; restricted area.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false New York Harbor, adjacent to the Stapleton Naval Station, Staten Island, New York; restricted area. 334.85 Section 334.85 Navigation and... RESTRICTED AREA REGULATIONS § 334.85 New York Harbor, adjacent to the Stapleton Naval Station, Staten Island...

  4. 30 CFR 785.19 - Surface coal mining and reclamation operations on areas or adjacent to areas including alluvial...

    Science.gov (United States)

    2010-07-01

    ... alluvial valley floor exists if it finds that— (i) Unconsolidated streamlaid deposits holding streams are... on areas or adjacent to areas including alluvial valley floors in the arid and semiarid areas west of....19 Surface coal mining and reclamation operations on areas or adjacent to areas including alluvial...

  5. Flux and genesis of CO2 degassing from volcanic-geothermal fields of Gulu-Yadong rift in the Lhasa terrane, South Tibet: Constraints on characteristics of deep carbon cycle in the India-Asia continent subduction zone

    Science.gov (United States)

    Zhang, Lihong; Guo, Zhengfu; Sano, Yuji; Zhang, Maoliang; Sun, Yutao; Cheng, Zhihui; Yang, Tsanyao Frank

    2017-11-01

    Gulu-Yadong rift (GYR) is the longest extensional, NE-SW-trending rift in the Himalayas and Lhasa terrane of South Tibet. Many volcanic-geothermal fields (VGFs), which comprise intense hot springs, steaming fissures, geysers and soil micro-seepage, are distributed in the GYR, making it ideal area for studying deep carbon emissions in the India-Asia continent subduction zone. As for the northern segment of GYR in the Lhasa terrane, its total flux and genesis of CO2 emissions are poorly understood. Following accumulation chamber method, soil CO2 flux survey has been carried out in VGFs (i.e., Jidaguo, Ningzhong, Sanglai, Tuoma and Yuzhai from south to north) of the northern segment of GYR. Total soil CO2 output of the northern GYR is about 1.50 × 107 t a-1, which is attributed to biogenic and volcanic-geothermal source. Geochemical characteristics of the volcanic-geothermal gases (including CO2 and He) of the northern GYR indicate their significant mantle-derived affinities. Combined with previous petrogeochemical and geophysical data, our He-C isotope modeling calculation results show that (1) excess mantle-derived 3He reflects degassing of volatiles related with partial melts from enriched mantle wedge induced by northward subduction of the Indian lithosphere, and (2) the crust-mantle interaction can provide continuous heat and materials for the overlying volcanic-geothermal system, in which magma-derived volatiles are inferred to experience significant crustal contamination during their migration to the surface.

  6. MR imaging of lumbar spondylolysis: signal intensity change in the pars interarticularis and adjacent structures

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Suk Whan; Lee, Ghi Jai; Shim, Jae Chan; Kim, Ho Kyun [Inje Univ. College of Medicine, Kimhae (Korea, Republic of)

    2001-05-01

    To assess changes in MR signal intensity in the pars interarticularis and adjacent structures in patients with lumbar spondylolysis. The MR images of 36 patients with lumbar spondylolysis, confirmed by plain radiographs, were retrospectively analyzed. Using a 1.0T unit, we evaluated the signal intensity of a total of 216 parts interarticulares and adjacent structures from L3 to L5, as seen on sagittal images, and differences between areas with and without spondylolysis. The signal intensity of T1-and T2-weighted images was graded 0(more hypointense than spinal body), 1(as isointense as spinal body), 2(more hyperintense than spinal body and more hypointense than epidural fat), or 3(as isointense as epidural fat). Signal intensity change in endplates and degree of spondylolisthesis were analyzed, and the relationship between these factors was determined. Spondylolysis was noted at L5 in 61 cases, at L4 in 22, and of L3 in no case. In three cases spondylolysis was unilateral, and in the remainder it was bilateral. The degree of signal intensity was the same on T1-and T2-weighted images, and no case was grade 0. Eighty-six of 133 areas without spondylolysis were grade 1, 43 were grade 2, and four were grade 3. In 42 of 47 cases, signal intensity change was localized at pedicles. Among 83 areas with spondylolysis,on the other hand, nine were grade 1, 48 were grade 2, and 26 were grade 3. Signal intensity change was most commonly observed at the pars interarticularis, pedicle, and lamina(50/74)({rho}<0.001). Signal intensity change at the pars interarticularis and adjacent structures was accompanied in most cases by degenerative endplate change(10/11) and spondylolisthesis(11/13)({rho}<0.001). In patients with spondylolysis, signal intensity was frequently higher at the pars interarticularis and adjacent structures, and is thought to have a close relationship with degenerative endplate change and spondylolisthesis. Increases in signal intensity at the pars

  7. MR imaging of lumbar spondylolysis: signal intensity change in the pars interarticularis and adjacent structures

    International Nuclear Information System (INIS)

    Jang, Suk Whan; Lee, Ghi Jai; Shim, Jae Chan; Kim, Ho Kyun

    2001-01-01

    To assess changes in MR signal intensity in the pars interarticularis and adjacent structures in patients with lumbar spondylolysis. The MR images of 36 patients with lumbar spondylolysis, confirmed by plain radiographs, were retrospectively analyzed. Using a 1.0T unit, we evaluated the signal intensity of a total of 216 parts interarticulares and adjacent structures from L3 to L5, as seen on sagittal images, and differences between areas with and without spondylolysis. The signal intensity of T1-and T2-weighted images was graded 0(more hypointense than spinal body), 1(as isointense as spinal body), 2(more hyperintense than spinal body and more hypointense than epidural fat), or 3(as isointense as epidural fat). Signal intensity change in endplates and degree of spondylolisthesis were analyzed, and the relationship between these factors was determined. Spondylolysis was noted at L5 in 61 cases, at L4 in 22, and of L3 in no case. In three cases spondylolysis was unilateral, and in the remainder it was bilateral. The degree of signal intensity was the same on T1-and T2-weighted images, and no case was grade 0. Eighty-six of 133 areas without spondylolysis were grade 1, 43 were grade 2, and four were grade 3. In 42 of 47 cases, signal intensity change was localized at pedicles. Among 83 areas with spondylolysis,on the other hand, nine were grade 1, 48 were grade 2, and 26 were grade 3. Signal intensity change was most commonly observed at the pars interarticularis, pedicle, and lamina(50/74)(ρ<0.001). Signal intensity change at the pars interarticularis and adjacent structures was accompanied in most cases by degenerative endplate change(10/11) and spondylolisthesis(11/13)(ρ<0.001). In patients with spondylolysis, signal intensity was frequently higher at the pars interarticularis and adjacent structures, and is thought to have a close relationship with degenerative endplate change and spondylolisthesis. Increases in signal intensity at the pars interarticularis and

  8. Russian aeromagnetic surveys of the Prince Charles Mountains and adjacent regions into the 21st century

    Science.gov (United States)

    Golynsky, Alexander; Golynsky, Dmitry; Kiselev, Alexander; Masolov, Valery

    2014-05-01

    Russian aeromagnetic investigations in the Prince Charles Mountains (PCM) and surrounding areas, seek to contribute data on the tectonics of Precambrian igneous belts and cratonic fragments, the crustal structure of the Lambert Rift system and other major aspects of Antarctic geology, critical to understanding continental growth processes (Golynsky et al., 2006). Over the past decade, the Polar Marine Geoscience Expedition projects acquired approximately 77,400 line-km of aeromagnetic data over the largely ice-covered regions of MacRobertson Land and Princess Elizabeth Land. The airborne surveys were performed with a standard profile spacing of 5 km and tie-line interval of 15-25 km. The total amount of the Russian aeromagnetic data collected in this region exceeded more than 165,000 line-km. Together with the PCMEGA and AGAP surveys (Damaske and McLean, 2005; Ferraccioli et al., 2011) the PMGE dataset forms the longest transect ever mapped in East Antarctica exceeding 1950 km in length. Several distinct crustal subdivisions are clearly differentiated in the magnetic data. The high-amplitude positive anomalies that extend around the Vestfold Hills and Rauer Islands are likely be attributed to the southern boundary of high-grade metamorphic Late Archean craton. The northern PCM that are composed by ~1 Ga orthogneiss and charnockite display a predominantly northeasterly trending magnetic fabric that continues to the eastern shoulder of the Lambert Rift. The aeromagnetic data from the Southern PCM reveal the spatial boundary of the Archaean Ruker Terrane that is characterized by a short-wavelength anomalies and the prominent Ruker Anomaly that is associated with a banded iron formation. The prominent alternating system of linear NE-SW positive and negative anomalies over the eastern shoulder of the Lambert Rift may reflect the western boundary of the Princess Elizabeth Land cratonic(?) block, although its relationships and tectonic origin remained largely ambiguous

  9. Sagittal Alignment As a Predictor of Clinical Adjacent Segment Pathology requiring Surgery after Anterior Cervical Arthrodesis

    Science.gov (United States)

    Park, Moon Soo; Kelly, Michael P.; Lee, Dong-Ho; Min, Woo-Kie; Rahman, Ra’Kerry K.; Riew, K. Daniel

    2014-01-01

    BACKGROUND CONTEXT Postoperative malalignment of the cervical spine may alter cervical spine mechanics, and put patients at risk for clinical adjacent segment pathology requiring surgery. PURPOSE To investigate whether a relationship exists between cervical spine sagittal alignment and clinical adjacent segment pathology requiring surgery (CASP-S) following anterior cervical fusion (ACF). STUDY DESIGN Retrospective matched study. PATIENT SAMPLE One hundred twenty two patients undergoing ACF from 1996 to 2008 were identified, with a minimum of 2 year follow-up. OUTCOME MEASURES Radiographs were reviewed to measure the sagittal alignment using C2 and C7 sagittal plumb lines, distance from the fusion mass plumb line to the C2 and C7 plumb lines, the alignment of the fusion mass, caudally adjacent disc angle, the sagittal slope angle of the superior endplate of the vertebra caudally adjacent to the fusion mass, T1 sagittal angle, overall cervical sagittal alignment, and curve patterns by Katsuura classification. METHODS One hundred twenty two patients undergoing ACF from 1996 to 2008 were identified, with a minimum of 1 year follow-up. Patients were divided into groups according to the development of CASP requiring surgery (Control / CASP-S) and by number/location of levels fused. Radiographs were reviewed to measure the sagittal alignment using C2 and C7 sagittal plumb lines, distance from the fusion mass plumb line to the C2 and C7 plumb lines, the alignment of the fusion mass, caudally adjacent disc angle, the sagittal slope angle of the superior endplate of the vertebra caudally adjacent to the fusion mass, T1 sagittal angle, overall cervical sagittal alignment, and curve patterns by Katsuura classification. Appropriate statistical tests were performed to calculate relationships between the variables and the development of CASP-S. No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related

  10. Hybrid dynamic stabilization: a biomechanical assessment of adjacent and supraadjacent levels of the lumbar spine.

    Science.gov (United States)

    Mageswaran, Prasath; Techy, Fernando; Colbrunn, Robb W; Bonner, Tara F; McLain, Robert F

    2012-09-01

    The object of this study was to evaluate the effect of hybrid dynamic stabilization on adjacent levels of the lumbar spine. Seven human spine specimens from T-12 to the sacrum were used. The following conditions were implemented: 1) intact spine; 2) fusion of L4-5 with bilateral pedicle screws and titanium rods; and 3) supplementation of the L4-5 fusion with pedicle screw dynamic stabilization constructs at L3-4, with the purpose of protecting the L3-4 level from excessive range of motion (ROM) and to create a smoother motion transition to the rest of the lumbar spine. An industrial robot was used to apply continuous pure moment (± 2 Nm) in flexion-extension with and without a follower load, lateral bending, and axial rotation. Intersegmental rotations of the fused, dynamically stabilized, and adjacent levels were measured and compared. In flexion-extension only, the rigid instrumentation at L4-5 caused a 78% decrease in the segment's ROM when compared with the intact specimen. To compensate, it caused an increase in motion at adjacent levels L1-2 (45.6%) and L2-3 (23.2%) only. The placement of the dynamic construct at L3-4 decreased the operated level's ROM by 80.4% (similar stability as the fusion at L4-5), when compared with the intact specimen, and caused a significant increase in motion at all tested adjacent levels. In flexion-extension with a follower load, instrumentation at L4-5 affected only a subadjacent level, L5-sacrum (52.0%), while causing a reduction in motion at the operated level (L4-5, -76.4%). The dynamic construct caused a significant increase in motion at the adjacent levels T12-L1 (44.9%), L1-2 (57.3%), and L5-sacrum (83.9%), while motion at the operated level (L3-4) was reduced by 76.7%. In lateral bending, instrumentation at L4-5 increased motion at only T12-L1 (22.8%). The dynamic construct at L3-4 caused an increase in motion at T12-L1 (69.9%), L1-2 (59.4%), L2-3 (44.7%), and L5-sacrum (43.7%). In axial rotation, only the placement of

  11. Reassessment of the geologic evolution of selected precambrian terranes in Brazil, based on SHRIMP U-Pb data, part 2: mineiro and Aracuai orogens and Southern Sao Francisco craton; Reavaliacao da evolucao geologica em terrenos pre-cambrianos brasileiros com base em novos dados U-Pb SHRIMP, parte 2: orogeno Aracuai, cinturao mineiro e craton Sao Francisco Meridional

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Luiz Carlos da; Pimentel, Marcio [Brasilia Univ., DF (Brazil). Inst. de Geociencias]. E-mail: luizcarlos@aneel.gov.br; Leite, Carlos Augusto; Vieira, Valter Salino; Silva, Marcio Antonio da; Paes, Vinicius Jose de Castro; Cardoso Filho, Joao Moraes [Companhia de Pesquisas de Recursos Minerais (CPRM), Belo Horizonte, MG (Brazil); Armstrong, Richard [Australian National Univ., Canberra (Australia). Research School of Earth Sciences; Noce, Carlos Mauricio; Pedrosa-Soares, Antonio Carlos [Minas Gerais Univ., Belo Horizonte (Brazil). Inst. de Geociencias. Centro de Pesquisa Manuel Teixeira da Costa; Carneiro, Mauricio Antonio [Ouro Preto Univ., MG (Brazil). Dept. de Geologia

    2002-12-15

    This paper discusses new zircon SHRIMP (Sensitive High Resolution Ion Microprobe) U-Pb geochronological data for 19 key-exposures of several geological units exposed at the eastern border of the Southern Sao Francisco Craton and at the adjacent Proterozoic Mineiro and Aracuai orogens. Samples were collected along several E-W tran sects, aiming at tracing the precise limit of the Sao Francisco Craton Archean basement, as well as assessing the extension of the successive proterozoic orogenic collages. Due to the complex geologic history and/or high grade metamorphism which most of the rock units investigated have undergone, zircon morphology and the U-Pb analytical data exhibit very complex patterns. These are characterized by a combination of inheritance, partial resetting and new zircon growth during high-grade metamorphism. As a consequence, very careful and detailed analyses of cathodoluminescence imagery were required to allow distinction between inheritance, newly melt-precipitated zircon and partially reset zircons, as well as between the ages of magmatic and metamorphic events. In the southeastern border of the craton 5 units yielded Archean crystallization ages ranging from ca. 3000-2700 Ma, with poorly constrained metamorphic ages ranging from ca. 2850 to 550 Ma. The TTG gneissic complex exposed to the east and south of the Quadrilatero Ferrifero, formerly ascribed to the Archean basement, have crystallization ages from ca. 2210 Ma to 2050 Ma, and can now be interpreted as representing pre- to syn-collisional magmatic phases of the Mineiro Belt. Metamorphic ages of ca. 2100 Ma and 560 Ma are also well constrained in zircon populations from these gneisses. The crystallization age of ca 1740 Ma observed for an alkaline granite of the Borrachudos Suite (intrusive into the Archean basement east of the Southern Espinhaco Range) confirmed previous conventional U-Pb data for this Paleoproterozoic rift-related magmatism. One of the major basement inliers within the

  12. Circummandibular Wires for Treatment of Dentoalveolar Fractures Adjacent to Edentulous Areas: A Report of Two Cases.

    Science.gov (United States)

    Maloney, Karl

    2015-09-01

    In general, dentoalveolar fractures are a common injury seen in emergency departments, dental offices, and oral and maxillofacial surgery practices. These injuries can be the result of direct trauma or indirect trauma. Direct trauma more often causes trauma to the maxillary dentition due to the exposure of the maxillary anterior teeth. Indirect trauma is usually the result of forced occlusion secondary to a blow to the chin or from a whiplash injury. Falls are the most common mechanism of injury seen in the pediatric group. In adolescents, many of these fractures are sustained during sporting activities. However, the use of mouth guards and other protective equipment has decreased this number. Most adult injuries are caused by motor vehicle accidents, contact sports, falls, bicycles, interpersonal violence, medical/dental mishaps, and industrial accidents. Early intervention to reduce and stabilize the fracture is required to establish a bony union and ensure correct function. Most dentoalveolar fractures have bilateral stable adjacent dentition and are treated with a closed technique utilizing an acid-etch/resin splint followed by splint removal at 4 weeks. Other inferior stabilization treatments used are arch bars and other wiring techniques. It is widely accepted that semirigid stabilization techniques, such as an acid-etch/resin splint or wiring procedures, are adequate to treat dentoalveolar fractures. This is in contrast to the treatment of mandible fractures where AO principles of rigid fixation are often followed. Fractures that are unable to be reduced sometimes necessitate an open reduction followed by internal fixation, sometimes using a secondary splint for mobile teeth. In those rare cases when there are not stable adjacent teeth bilaterally other modalities must be considered. In the present report, two cases are presented where circummandibular wires were used to treat fractured mandibular dentoalveolar segments adjacent to edentulous areas.

  13. Agricultural intensification exacerbates spillover effects on soil biogeochemistry in adjacent forest remnants.

    Directory of Open Access Journals (Sweden)

    Raphael K Didham

    Full Text Available Land-use intensification is a central element in proposed strategies to address global food security. One rationale for accepting the negative consequences of land-use intensification for farmland biodiversity is that it could 'spare' further expansion of agriculture into remaining natural habitats. However, in many regions of the world the only natural habitats that can be spared are fragments within landscapes dominated by agriculture. Therefore, land-sparing arguments hinge on land-use intensification having low spillover effects into adjacent protected areas, otherwise net conservation gains will diminish with increasing intensification. We test, for the first time, whether the degree of spillover from farmland into adjacent natural habitats scales in magnitude with increasing land-use intensity. We identified a continuous land-use intensity gradient across pastoral farming systems in New Zealand (based on 13 components of farmer input and soil biogeochemistry variables, and measured cumulative off-site spillover effects of fertilisers and livestock on soil biogeochemistry in 21 adjacent forest remnants. Ten of 11 measured soil properties differed significantly between remnants and intact-forest reference sites, for both fenced and unfenced remnants, at both edge and interior. For seven variables, the magnitude of effects scaled significantly with magnitude of surrounding land-use intensity, through complex interactions with fencing and edge effects. In particular, total C, total N, δ15N, total P and heavy-metal contaminants of phosphate fertilizers (Cd and U increased significantly within remnants in response to increasing land-use intensity, and these effects were exacerbated in unfenced relative to fenced remnants. This suggests movement of livestock into surrounding natural habitats is a significant component of agricultural spillover, but pervasive changes in soil biogeochemistry still occur through nutrient spillover channels alone

  14. Effects of Bt-transgenic rice cultivation on planktonic communities in paddy fields and adjacent ditches

    International Nuclear Information System (INIS)

    Liu, Yongbo; Liu, Fang; Wang, Chao; Quan, Zhanjun; Li, Junsheng

    2016-01-01

    The non-target effects of transgenic plants are issues of concern; however, their impacts in cultivated agricultural fields and adjacent natural aquatic ecosystems are poorly understood. We conducted field experiments during two growing seasons to determine the effects of cultivating Bacillus thuringiensis (Bt)-transgenic rice on the phytoplankton and zooplankton communities in a paddy field and an adjacent ditch. Bt toxin was detected in soil but not in water. Water quality was not significantly different between non-Bt and Bt rice fields, but varied among up-, mid- and downstream locations in the ditch. Cultivation of Bt-transgenic rice had no effects on zooplankton communities. Phytoplankton abundance and biodiversity were not significantly different between transgenic and non-transgenic rice fields in 2013; however, phytoplankton were more abundant in the transgenic rice field than in the non-transgenic rice field in 2014. Water quality and rice type explained 65.9% and 12.8% of this difference in 2014, respectively. Phytoplankton and zooplankton were more abundant in mid- and downstream, than upstream, locations in the ditch, an effect that we attribute to water quality differences. Thus, the release of Bt toxins into field water during the cultivation of transgenic crops had no direct negative effects on plankton community composition, but indirect effects that alter environmental conditions should be taken into account during the processes of management planning and policymaking. - Highlights: • We detect fusion Cry1Ab/1Ac proteins from Bt rice entering into aquatic ecosystems. • Bt-transgenic rice cultivation have no significant effect on zooplankton community. • Bt-transgenic rice cultivation have indirect effect on phytoplankton community. • Water quality explains the difference of plankton communities in adjacent ditches.

  15. Acceptable Toxicity After Stereotactic Body Radiation Therapy for Liver Tumors Adjacent to the Central Biliary System

    Energy Technology Data Exchange (ETDEWEB)

    Eriguchi, Takahisa; Takeda, Atsuya; Sanuki, Naoko; Oku, Yohei; Aoki, Yousuke [Radiation Oncology Center, Ofuna Chuo Hospital, Kanagawa (Japan); Shigematsu, Naoyuki [Department of Radiology, Keio University School of Medicine, Tokyo (Japan); Kunieda, Etsuo, E-mail: kunieda-mi@umin.ac.jp [Department of Radiation Oncology, Tokai University, Kanagawa (Japan)

    2013-03-15

    Purpose: To evaluate biliary toxicity after stereotactic body radiation therapy (SBRT) for liver tumors. Methods and Materials: Among 297 consecutive patients with liver tumors treated with SBRT of 35 to 50 Gy in 5 fractions, patients who were irradiated with >20 Gy to the central biliary system (CBS), including the gallbladder, and had follow-up times >6 months were retrospectively analyzed. Toxicity profiles, such as clinical symptoms and laboratory and radiologic data especially for obstructive jaundice and biliary infection, were investigated in relation to the dose volume and length relationship for each biliary organ. Results: Fifty patients with 55 tumors were irradiated with >20 Gy to the CBS. The median follow-up period was 18.2 months (range, 6.0-80.5 months). In the dose length analysis, 39, 34, 14, and 2 patients were irradiated with >20 Gy, >30 Gy, >40 Gy, and >50 Gy, respectively, to >1 cm of the biliary tract. Seven patients were irradiated with >20 Gy to >20% of the gallbladder. Only 2 patients experienced asymptomatic bile duct stenosis. One patient, metachronously treated twice with SBRT for tumors adjacent to each other, had a transient increase in hepatic and biliary enzymes 12 months after the second treatment. The high-dose area >80 Gy corresponded to the biliary stenosis region. The other patient experienced biliary stenosis 5 months after SBRT and had no laboratory changes. The biliary tract irradiated with >20 Gy was 7 mm and did not correspond to the bile duct stenosis region. No obstructive jaundice or biliary infection was found in any patient. Conclusions: SBRT for liver tumors adjacent to the CBS was feasible with minimal biliary toxicity. Only 1 patient had exceptional radiation-induced bile duct stenosis. For liver tumors adjacent to the CBS without other effective treatment options, SBRT at a dose of 40 Gy in 5 fractions is a safe treatment with regard to biliary toxicity.

  16. Malaria vectors in Lake Victoria and adjacent habitats in western Kenya.

    Directory of Open Access Journals (Sweden)

    Noboru Minakawa

    Full Text Available The prevalence of malaria among the residents of the Lake Victoria basin remains high. The environment associated with the lake may maintain a high number of malaria vectors. Lake habitats including water hyacinths have been suspected to be the source of vectors. This study investigated whether malaria vectors breed in the lake habitats and adjacent backwater pools. Anopheline larvae were collected within the littoral zone of the lake and adjacent pools located along approximately 24.3 km of the lakeshore in western Kenya, and their breeding sites characterized. Three primary vector species, Anopheles arabiensis, Anopheles gambiae s.s. and Anopheles funestus s.s., and three potential vectors, were found in the lake habitats. Unexpectedly, An. arabiensis was the most dominant vector species in the lake sampling sites. Its habitats were uncovered or covered with short grass. A potential secondary malaria vector, Anopheles rivulorum, dominated the water hyacinths in the lake. Most breeding sites in the lake were limited to areas that were surrounded by tall emergent plants, including trees, and those not exposed to waves. Nearly half of adjacent habitats were lagoons that were separated from the lake by sand bars. Lagoons contained a variety of microhabitats. Anopheles arabiensis dominated open habitats, whereas An. funestus s.s. was found mainly in vegetated habitats in lagoons. The current study confirmed that several breeding sites are associated with Lake Victoria. Given that Lake Victoria is the second largest lake in the world, the lake related habitats must be extensive; therefore, making targeted vector control difficult. Further exploration is necessary to estimate the effects of lake associated habitats on malaria transmission so as to inform a rational decision-making process for vector control.

  17. Effects of Bt-transgenic rice cultivation on planktonic communities in paddy fields and adjacent ditches

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yongbo, E-mail: liuyb@craes.org.cn [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Liu, Fang [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Wang, Chao [Pearl River Fisheries Research Institute, Chinese Academy of Fishery Science, Guangzhou 510380 (China); Quan, Zhanjun [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Li, Junsheng, E-mail: lijsh@creas.org.cn [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China)

    2016-09-15

    The non-target effects of transgenic plants are issues of concern; however, their impacts in cultivated agricultural fields and adjacent natural aquatic ecosystems are poorly understood. We conducted field experiments during two growing seasons to determine the effects of cultivating Bacillus thuringiensis (Bt)-transgenic rice on the phytoplankton and zooplankton communities in a paddy field and an adjacent ditch. Bt toxin was detected in soil but not in water. Water quality was not significantly different between non-Bt and Bt rice fields, but varied among up-, mid- and downstream locations in the ditch. Cultivation of Bt-transgenic rice had no effects on zooplankton communities. Phytoplankton abundance and biodiversity were not significantly different between transgenic and non-transgenic rice fields in 2013; however, phytoplankton were more abundant in the transgenic rice field than in the non-transgenic rice field in 2014. Water quality and rice type explained 65.9% and 12.8% of this difference in 2014, respectively. Phytoplankton and zooplankton were more abundant in mid- and downstream, than upstream, locations in the ditch, an effect that we attribute to water quality differences. Thus, the release of Bt toxins into field water during the cultivation of transgenic crops had no direct negative effects on plankton community composition, but indirect effects that alter environmental conditions should be taken into account during the processes of management planning and policymaking. - Highlights: • We detect fusion Cry1Ab/1Ac proteins from Bt rice entering into aquatic ecosystems. • Bt-transgenic rice cultivation have no significant effect on zooplankton community. • Bt-transgenic rice cultivation have indirect effect on phytoplankton community. • Water quality explains the difference of plankton communities in adjacent ditches.

  18. Sucrose-Metabolizing Enzymes in Transport Tissues and Adjacent Sink Structures in Developing Citrus Fruit 1

    Science.gov (United States)

    Lowell, Cadance A.; Tomlinson, Patricia T.; Koch, Karen E.

    1989-01-01

    Juice tissues of citrus lack phloem; therefore, photosynthates enroute to juice sacs exit the vascular system on the surface of each segment. Areas of extensive phloem unloading and transport (vascular bundles + segment epidermis) can thus be separated from those of assimilate storage (juice sacs) and adjacent tissues where both processes occur (peel). Sugar composition, dry weight accumulation, and activities of four sucrose-metabolizing enzymes (soluble and cell-wall-bound acid invertase, alkaline invertase, sucrose synthase, and sucrose phosphate synthase) were measured in these transport and sink tissues of grapefruit (Citrus paradisi Macf.) to determine more clearly whether a given enzyme appeared to be more directly associated with assimilate transport versus deposition or utilization. Results were compared at three developmental stages. Activity of sucrose (per gram fresh weight and per milligram protein) extracted from zones of extensive phloem unloading and transport was significantly greater than from adjacent sink tissues during the stages (II and III) when juice sacs grow most rapidly. In stage II fruit, activity of sucrose synthase also significantly surpassed that of all other sucrose-metabolizing enzymes in extracts from the transport tissues (vascular bundles + segment epidermis). In contrast, sucrose phosphate synthase and alkaline invertase at this stage of growth were the most active enzymes from adjacent, rapidly growing, phloem-free sink tissues (juice sacs). Activity of these two enzymes in extracts from juice sacs was significantly greater than that form the transport tissues (vascular bundles + segment epidermis). Soluble acid invertase was the most active enzyme in extracts from all tissues of very young fruit (stage I), including nonvascular regions, but nearly disappeared prior to the onset of juice sac sugar accumulation. The physiological function of high sucrose synthase activity in the transport tissues during rapid sucrose import

  19. Analysis of MRI signal changes in the adjacent pedicle of adolescent patients with fresh lumbar spondylolysis.

    Science.gov (United States)

    Goda, Yuichiro; Sakai, Toshinori; Sakamaki, Tadanori; Takata, Yoichiro; Higashino, Kosaku; Sairyo, Koichi

    2014-09-01

    The purpose of this study is to investigate a discrepancy between MRI and computed tomography (CT) findings in the spinal level distribution of spondylolysis. Recent advances in MRI have led to the early diagnosis of spondylolysis. Therefore, bony healing can be expected before the condition has a chance to worsen. In this study, we used MRI to examine the changes in spinal level signals in the pedicles adjacent to the pars interarticularis in adolescents with fresh lumbar spondylolysis. We then compared spinal level distribution of spondylolysis with that of previous results obtained by multidetector CT. The study included 98 adolescent patients (31 women and 67 men; mean age, 13.6 years; age range, 9-18 years) with fresh lumbar spondylolysis who showed MRI signal changes in the adjacent pedicle. An MRI signal change was defined as a high signal change on fat-suppressed imaging. MRI signal changes were detected in 150 adjacent pedicles of 101 vertebrae. Of these vertebrae, MRI signal changes in only 67 (66.3%) corresponded to L5, while changes in 34 (33.7%) corresponded to L3 or L4. In our follow-up study, the bone-healing rate with no vertebral defect was 100% at L3, 97.1% at L4, and 84.4% at L5. In addition, 11 of 34 (32.4%) vertebrae with signal changes at L3 or L4 occurred with L5 terminal-stage spondylolysis (no MRI signal change). MRI revealed a higher prevalence of L3 or L4 spondylolysis than observed with CT.

  20. An Adaptive Model for Calculating the Correlation Degree of Multiple Adjacent Signalized Intersections

    Directory of Open Access Journals (Sweden)

    Linhong Wang

    2013-01-01

    Full Text Available As an important component of the urban adaptive traffic control system, subarea partition algorithm divides the road network into some small subareas and then determines the optimal signal control mode for each signalized intersection. Correlation model is the core of subarea partition algorithm because it can quantify the correlation degree of adjacent signalized intersections and decides whether these intersections can be grouped into one subarea. In most cases, there are more than two intersections in one subarea. However, current researches only focus on the correlation model for two adjacent intersections. The objective of this study is to develop a model which can calculate the correlation degree of multiple intersections adaptively. The cycle lengths, link lengths, number of intersections, and path flow between upstream and downstream coordinated phases were selected as the contributing factors of the correlation model. Their jointly impacts on the performance of the coordinated control mode relative to the isolated control mode were further studied using numerical experiments. The paper then proposed a correlation index (CI as an alternative to relative performance. The relationship between CI and the four contributing factors was established in order to predict the correlation, which determined whether adjacent intersections could be partitioned into one subarea. A value of 0 was set as the threshold of CI. If CI was larger than 0, multiple intersections could be partitioned into one subarea; otherwise, they should be separated. Finally, case studies were conducted in a real-life signalized network to evaluate the performance of the model. The results show that the CI simulates the relative performance well and could be a reliable index for subarea partition.

  1. The genus Alphitobius Stephens (Coleoptera, Tenebrionidae, Alphitobiini in Africa and adjacent islands

    Directory of Open Access Journals (Sweden)

    Wolfgang Schawaller

    2014-06-01

    Full Text Available All species of the genus Alphitobius Stephens, 1829 (Alphitobiini Reitter, 1917, subfamily Tenebrioninae Latreille, 1802 from Africa and adjacent islands are revised. New species: Alphitobius capitaneus sp. n. from Kenya. New synonyms: Cryptops ulomoides Solier, 1851, syn. n. of Alphitobius diaperinus (Panzer, 1796; Alphitobius rufus Ardoin, 1976, syn. n. of Alphitobius hobohmi Koch, 1953; Peltoides (Micropeltoides crypticoides Pic, 1916, syn. n. of Peltoides (Micropeltoides opacus (Gerstaecker, 1871, comb. n. Homonym: Alphitobius ulomoides Koch, 1953 = Alphitobius arnoldi nom. n. New combinations from Alphitobius: Ulomoides basilewskyi (Ardoin, 1969, comb. n.; Peltoides (Micropeltoides opacus (Gerstaecker, 1871, comb. n. Figures of all examined species are added and a species key is compiled.

  2. A review of the natural history of adult Cetoniinae (Coleoptera: Scarabaeidae) from Argentina and adjacent countries.

    Science.gov (United States)

    Di Iorio, Osvaldo

    2014-04-17

    A compilation of the known natural history of adult Cetoniinae (Coleoptera: Scarabaeidae) from Argentina and adjacent countries is provided. Food items of adult Cetoniinae include pollen and/or nectar (flower visitors), sap and/or slime flux, ripened fruits on plants, green tissues and leaves, and honey. Of the 36 species of Cetoniinae from Argentina, food items are known only for 11 species (30.5%). Attraction to light and bait-traps, adult activity periods, vertebrate predators, and the occurrence in bird nests are presented and discussed. Other insects that share the same food sources and bait-traps with Cetoniinae are mentioned.

  3. Target migration from re-inflation of adjacent atelectasis during lung stereotactic body radiotherapy.

    Science.gov (United States)

    Mao, Bijing; Verma, Vivek; Zheng, Dandan; Zhu, Xiaofeng; Bennion, Nathan R; Bhirud, Abhijeet R; Poole, Maria A; Zhen, Weining

    2017-06-10

    Stereotactic body radiotherapy (SBRT) is a widely accepted option for the treatment of medically inoperable early-stage non-small cell lung cancer (NSCLC). Herein, we highlight the importance of interfraction image guidance during SBRT. We describe a case of early-stage NSCLC associated with segmental atelectasis that translocated 15 mm anteroinferiorly due to re-expansion of the adjacent segmental atelectasis following the first fraction. The case exemplifies the importance of cross-sectional image-guided radiotherapy that shows the intended target, as opposed to aligning based on rigid anatomy alone, especially in cases associated with potentially "volatile" anatomic areas.

  4. Literature and data review for the surface-water pathway: Columbia River and adjacent coastal areas

    International Nuclear Information System (INIS)

    Walters, W.H.; Dirkes, R.L.; Napier, B.A.

    1992-11-01

    As part of the Hanford Environmental Dose Reconstruction (HEDR) Project, Battelle, Pacific Northwest Laboratories reviewed literature and data on radionuclide concentrations and distribution in the water, sediment, and biota of the Columbia River and adjacent coastal areas. Over 600 documents were reviewed including Hanford reports, reports by offsite agencies, journal articles, and graduate theses. Radionuclide concentration data were used in preliminary estimates of individual dose for the period 1964 through 1966. This report summarizes the literature and database reviews and the results of the preliminary dose estimates

  5. Pollution parameters determination in water coast dispersion adjacent Carretas Point sub aquatic emissary

    International Nuclear Information System (INIS)

    Suarez Antola, R.; Malek, A.; Odino, R.; Souto, B.; Artucio, G.; Baraibar, J.

    1996-01-01

    It describes some results about transport processes, tracer techniques in Carretas Point sub aquatic emissary, discharge plume and emissary adjacent water coast in summer season. An overtaking and stability plume was verified. A contaminant unexpected and effusion localized was simulated. Scale effect near one coefficient was obtain Longitudinal dispersion coefficients and 1m2/seg and 0,02m2/seg transversal was estimated. The possibility to obtain information from first stages of transport analyzing fluorescence trace stain videos through geometric tools is discussed

  6. Histopathological effects of intraoperative radiotherapy on pancreas and adjacent tissues: a postmortem analysis

    International Nuclear Information System (INIS)

    Hoekstra, H.J.; Restrepo, C.; Kinsella, T.J.; Sindelar, W.F.

    1988-01-01

    Intraoperative radiotherapy (IORT) has been utilized in the treatment of resectable and unresectable pancreatic carcinoma at the National Cancer Institute. Detailed autopsy analyses of the radiation effects on the pancreas and adjacent tissues were performed on 13 patients dying at various times following therapy. IORT can induce a progressive retroperitoneal fibrosis and fibrosis of the porta hepatis in patients with resectable pancreatic carcinoma. In unresectable pancreatic carcinoma, the major expression of intraoperative irradiation with external beam irradiation is a progressive fibrosis of the pancreas with vascular sclerosis, nerve degeneration, atrophy of acinar cells, and atypical changes in the ducts of the pancreas, as well as degenerative changes of the pancreatic tumor

  7. On optical spectra of the NGC 6677 galaxy and the adjacent bright compact object

    International Nuclear Information System (INIS)

    Chuvaev, K.K.

    1987-01-01

    Spectral observations of NGC 6677 galaxy and the adjacent object carried out during six nights on the spectrograph with the image tube of 2.6-m Shain telescope showed, that the bright compact object is a star belonging to our galaxy but not an active galaxy. The NGC 6677 galaxy has sufficiently rich emission spectrum. On the basis of measured values of red shift Z, the inclination and the extent of emission lines, the mass of the galaxy has been estimated (M=7x10 9 M Sun )

  8. Literature and data review for the surface-water pathway: Columbia River and adjacent coastal areas

    Energy Technology Data Exchange (ETDEWEB)

    Walters, W.H.; Dirkes, R.L.; Napier, B.A.

    1992-11-01

    As part of the Hanford Environmental Dose Reconstruction (HEDR) Project, Battelle, Pacific Northwest Laboratories reviewed literature and data on radionuclide concentrations and distribution in the water, sediment, and biota of the Columbia River and adjacent coastal areas. Over 600 documents were reviewed including Hanford reports, reports by offsite agencies, journal articles, and graduate theses. Radionuclide concentration data were used in preliminary estimates of individual dose for the period 1964 through 1966. This report summarizes the literature and database reviews and the results of the preliminary dose estimates.

  9. Literature and data review for the surface-water pathway: Columbia River and adjacent coastal areas

    International Nuclear Information System (INIS)

    Walters, W.H.; Dirkes, R.L.; Napier, B.A.

    1992-04-01

    As part of the Hanford Environmental Dose Reconstruction Project, Pacific Northwest Laboratory reviewed literature and data on radionuclide concentrations and distribution in the water, sediment, and biota of the Columbia River and adjacent coastal areas. Over 600 documents were reviewed including Hanford reports, reports by offsite agencies, journal articles, and graduate theses. Certain radionuclide concentration data were used in preliminary estimates of individual dose for the 1964--1966 time period. This report summarizes the literature and database review and the results of the preliminary dose estimates

  10. Health and function assessments in two adjacent Danish birth cohorts of centenarians

    DEFF Research Database (Denmark)

    Vestergaard, Sonja; Andersen-Ranberg, Karen; Skytthe, Axel

    2016-01-01

    Using the results from measures of functional ability, cognitive and physical performance from two adjacent birth cohorts of 100-year-old adults, we aimed to elucidate the possible impact of difference in participation rates, design, and interviewer mode. Participants were birth cohort members born...... proportions of DK-1911 independently performed all activities of daily living (ADL) compared to DK-1910, but only significantly for toileting, bathing, and feeding (all p examination (MMSE) score was higher in DK-1911 than in DK-1910 (23.5 vs. 21.0; p

  11. Odonata (Insecta diversity of Salim Ali Bird Sanctuary and its adjacent areas in Thattekkad, Kerala, India

    Directory of Open Access Journals (Sweden)

    A.P. Varghese

    2014-06-01

    Full Text Available Odonata diversity of Salim Ali Bird Sanctuary and its adjacent areas in Thattekkad, Kerala, India were documented from 2010 to 2012. Opportunistic observations were carried out to record species diversity. Eighty-two species of Odonata, which included 51 species of Anisoptera (dragonflies and 31 species of Zygoptera (damselflies, were recorded during the study. Of this 21 species are endemic to the Western Ghats. The presence of the IUCN categorized nearly threatened species like Megalogomphus hannyngtoni and vulnerable species like Platysticta deccanensis and Protosticta sanguinostigma is remarkable.

  12. Experimental study of natural convection adjacent to an isothermal vertical ice cylinder in cold pure water

    International Nuclear Information System (INIS)

    Riu, Kap Jong; Yea, Yong Taeg; Park, Sang Hee

    1991-01-01

    A natural convection adjacent to an isothermal vertical ice cylinder is studied experimentally in cold pure water. The experiments are carried out as changing the temperature of the ambient water and then the flow and heat transfer characteristics is visualized and observed. It is shown that flow patterns are steady state upflow, unsteady state flow, steady state dual flow, and steady state downflow. There is also obtained a heat transfer coefficient and mean Nusselt number at various ambient temperature. These results are in good agreement with the theoretical ones. (Author)

  13. Variabilidade espacial e disponibilidade de cobre e zinco em solos de vinhedos e adjacências

    OpenAIRE

    Valladares,Gustavo Souza; Azevedo,Emílio Carlos de; Camargo,Otávio Antônio de; Grego,Célia Regina; Rastoldo,Alessandra Maria Cia Silva

    2009-01-01

    Com o tempo, o uso agrícola pode levar à contaminação do solo por metais pesados, principalmente por se servir de insumos e agroquímicos que possuem cobre e zinco em sua composição. O objetivo deste trabalho foi determinar os teores de cobre e zinco disponíveis no solo extraídos com DTPA e avaliar sua distribuição espacial empregando a geoestatística em áreas de vinhedos comerciais e experimentais e sob outros usos e coberturas nas adjacências das plantações. Foram coletadas amostras de terra...

  14. Effect of fluoridated milk on enamel demineralization adjacent to fixed orthodontic appliances

    DEFF Research Database (Denmark)

    Sköld-Larsson, Kerstin; Sollenius, Ola; Karlsson, Lena

    2012-01-01

    Abstract Objective. To investigate the effect of daily intake of fluoridated milk on enamel demineralization adjacent to fixed orthodontic brackets assessed with quantitative light-induced fluorescence (QLF). Materials and methods. Sixty-four healthy adolescents (13-18 years) undergoing orthodontic...... amount of milk without fluoride. The intervention period was 12 weeks and the end-point was mineral gain or loss in enamel, assessed by QLF on two selected sites from each individual. The attrition rate was 12.5% and 112 sites were included in the final evaluation. Results. There was no statistically...

  15. Adjacent-cell Preconditioners for solving optically thick neutron transport problems

    International Nuclear Information System (INIS)

    Azmy, Y.Y.

    1994-01-01

    We develop, analyze, and test a new acceleration scheme for neutron transport methods, the Adjacent-cell Preconditioner (AP) that is particularly suited for solving optically thick problems. Our method goes beyond Diffusion Synthetic Acceleration (DSA) methods in that it's spectral radius vanishes with increasing cell thickness. In particular, for the ID case the AP method converges immediately, i.e. in one iteration, to 10 -4 pointwise relative criterion in problems with dominant cell size of 10 mfp or thicker. Also the AP has a simple formalism and is cell-centered hence, multidimensional and high order extensions are easier to develop, and more efficient to implement

  16. Reassessment of the geologic evolution of selected precambrian terranes in Brazil, based on new SHRIMP U-Pb data, part 1: central-eastern border of Sao Francisco Craton in Bahia state, Brazil

    International Nuclear Information System (INIS)

    Silva, Luiz Carlos da; Pimentel, Marcio; Jost, Hardy; Armstrong, Richard

    2002-01-01

    This paper discusses new U-Pb SHRIMP zircon data for 12 key-exposures of several geological units exposed at the eastern border of the Sao Francisco Craton. The samples represent mostly Archean basement units within the Paleoproterozoic Eastern Bahia Belt (Orogen). Samples were collected along several E-W tran sects trying to more accurately assess the areal distribution of the Archean polycyclic basement of the Sao Francisco Craton and to identify the limits of Paleoproterozoic metamorphic overprint resulting from the development of the Eastern Bahia Orogen. Owing to the polycyclic evolution and/or high grade metamorphic conditions which most of the rock units investigated have undergone, zircon morphology and the U-Pb analytical data exhibit very complex patterns. These are characterized by a combination of inheritance, partial resetting and new zircon growth during high grade metamorphism. As a consequence, very careful and detailed analyses of cathodoluminescence imagery were required to allow distinction between inheritance, newly melt-precipitated zircon and partially reset zircons, as well as between the ages of magmatic and metamorphic events. Except for one unit (sample LH 44), which present crystallization age of ca 3000 Ma - interpreted, therefore, as the eastern extension of the Serrinha Craton - the others are ascribed to two major age groups at ca. 2870-2500 Ma and ca. 2200?-2030 Ma. The former group includes ortho gneisses with crystallization ages between ca. 2870-2500 Ma, which have been mapped and interpreted, in its major extension, as juvenile Paleoproterozoic arc (Itabuna and Salvador-Curaca belts/domains). The new data presented in this study, however, indicate that these ortho gneisses represent a multi-episodic collage of primitive Archean orogenic arcs, which gave rise to the Archean basement of that part of the Sao Francisco Craton. All the investigated zircon populations were extensively recrystallized at ca. 2080-2050 Ma as a result of

  17. Punching shear in reinforced concrete flat slabs with hole adjacent to the column and moment transfer

    Directory of Open Access Journals (Sweden)

    D. C. Oliveira

    Full Text Available The structural behavior and the ultimate punching shear resistance of internal reinforced concrete flat slab-column connections, with one hole adjacent to the column, with or without flexural moment transfer of the slab to the column was investigated. Main variables were: the existence whether or not hole, flexural reinforcement layout and ratio, the direction and sense of the moment transferred and the eccentricity of the load (M (moment transferred to column / V (shear ratio at the connection - 0,50 m or 0,25 m. Seven internal slab-column joining were tested and ultimate loads, cracking, deflections, concrete and reinforcement strains were analyzed. The existence of hole adjacent to the smaller column dimension, the hole dimension, flexural reinforcement rate and placing, the variation of relation Mu/Vu in function of the load, and, than, of eccentricity of the load, influenced the slabs behavior and rupture load. Test results were compared with the estimations from CEB-FIP/MC1990 [7], EC2/2004 [12], ACI-318:2011 [1] and NBR 6118:2007 [5]. ACI [1] and EC2 [12] presented most conservative estimates, although have presented some non conservative estimates. Brazilian NBR [5], even though being partly based in EC2 [12], presented smaller conservative estimates and more non conservative estimates. A modification on all codes is proposed for taking in account the moment caused by the eccentricity at the critical perimeter for slabs with holes.

  18. Hybrid NiCoOx adjacent to Pd nanoparticles as a synergistic electrocatalyst for ethanol oxidation

    Science.gov (United States)

    Wang, Wei; Yang, Yan; Liu, Yanqin; Zhang, Zhe; Dong, Wenkui; Lei, Ziqiang

    2015-01-01

    To improve the electrocatalytic activity of Pd for ethanol oxidation, hybrid NiCoOx adjacent to Pd catalyst (Pd-NiCoOx/C) is successfully synthesized. Physical characterization shows NiCoOx is closely adjacent to Pd nanoparticles in Pd-NiCoOx/C catalyst, which leads to Strong Metal-Support Interactions (SMSI) between the NiCoOx and Pd nanoparticles, in favor of the electrocatalytic properties. The Pd-NiCoOx/C catalyst is estimated to own larger electrochemically active surface area than Pd/C and Pd-NiO/C catalysts. Moreover, compared to Pd/C catalyst, the onset potential of Pd-NiCoOx/C catalyst is negative 40 mV for ethanol oxidation. Noticeably, the current density of Pd-NiCoOx/C catalyst is 2.05 and 1.43 times higher contrasted to Pd/C and Pd-NiO/C catalysts accordingly. Importantly, the Pd-NiCoOx/C catalyst exhibits better stability during ethanol oxidation, which is a promising electrocatalyst for application in direct alkaline alcohol fuel cells.

  19. Measuring Crowdedness between Adjacent Stations in an Urban Metro System: a Chinese Case Study

    Directory of Open Access Journals (Sweden)

    Liudan Jiao

    2017-12-01

    Full Text Available The urban metro system has been widely appreciated as the most important component in urban infrastructures. It plays a critical role in promoting urban social and economic development, and particularly in reducing the urban traffic congestion. However, there are various inherent problems with operating metro systems, which typically involve the crowdedness both at stations and inside vehicles. Both policymakers and academic researchers in China have paid little attention to the crowdedness between metro stations. In order to solve the problem of crowdedness, it is necessary to develop a method to evaluate the level of crowdedness. This work establishes a model to measure the crowdedness between adjacent stations in a metro system based on the load factor principle, passenger standing density, and other factors such as the metro operation schedule and estimations of passenger flows. The Chongqing Metro Line 3 in China is used as a case study to demonstrate the application of the evaluation model. The case study reveals that the model introduced in this study can assist with assessing the crowdedness level between adjacent stations in a metro line. The model is an effective tool for helping the metro management and administration understand the level of crowdedness, apply proper methods to mitigate the crowdedness, and thus improve the quality of the service for those utilizing the metro system.

  20. Activation gating kinetics of GIRK channels are mediated by cytoplasmic residues adjacent to transmembrane domains.

    Science.gov (United States)

    Sadja, Rona; Reuveny, Eitan

    2009-01-01

    G-protein-coupled inwardly rectifying potassium channels (GIRK/Kir3.x) are involved in neurotransmission-mediated reduction of excitability. The gating mechanism following G protein activation of these channels likely proceeds from movement of inner transmembrane helices to allow K(+) ions movement through the pore of the channel. There is limited understanding of how the binding of G-protein betagamma subunits to cytoplasmic regions of the channel transduces the signal to the transmembrane regions. In this study, we examined the molecular basis that governs the activation kinetics of these channels, using a chimeric approach. We identified two regions as being important in determining the kinetics of activation. One region is the bottom of the outer transmembrane helix (TM1) and the cytoplasmic domain immediately adjacent (the slide helix); and the second region is the bottom of the inner transmembrane helix (TM2) and the cytoplasmic domain immediately adjacent. Interestingly, both of these regions are sufficient in mediating the kinetics of fast activation gating. This result suggests that there is a cooperative movement of either one of these domains to allow fast and efficient activation gating of GIRK channels.

  1. Generation of Chimeric RNAs by cis-splicing of adjacent genes (cis-SAGe) in mammals.

    Science.gov (United States)

    Zhuo, Jian-Shu; Jing, Xiao-Yan; Du, Xin; Yang, Xiu-Qin

    2018-02-20

    Chimeric RNA molecules, possessing exons from two or more independent genes, are traditionally believed to be produced by chromosome rearrangement. However, recent studies revealed that cis-splicing of adjacent genes (cis- SAGe) is one of the major mechanisms underlying the formation of chimeric RNAs. cis-SAGe refers to intergenic splicing of directly adjacent genes with the same transcriptional orientation, resulting in read-through transcripts, termed chimeric RNAs, which contain sequences from two or more parental genes. cis-SAGe was first identified in tumor cells, since then its potential in carcinogenesis has attracted extensive attention. More and more scientists are focusing on it. With the development of research, cis-SAGe was found to be ubiquitous in various normal tissues, and might make a crucial contribution to the formation of novel genes in the evolution of genomes. In this review, we summarize the splicing pattern, expression characteristics, possible mechanisms, and significance of cis-SAGe in mammals. This review will be helpful for general understanding of the current status and development tendency of cis-SAGe.

  2. The tiger beetles (Coleoptera, Carabidae, Cicindelinae) of Israel and adjacent lands.

    Science.gov (United States)

    Matalin, Andrey V; Chikatunov, Vladimir I

    2016-01-01

    Based on field studies, museums collections and literature sources, the current knowledge of the tiger beetle fauna of Israel and adjacent lands is presented. In Israel eight species occur, one of them with two subspecies, while in the Sinai Peninsula nine species of tiger beetles are now known. In the combined regions seven genera from two tribes were found. The Rift Valley with six cicindelids species is the most specious region of Israel. Cylindera contorta valdenbergi and Cicindela javeti azari have localized distributions and should be considered regional endemics. A similarity analysis of the tiger beetles faunas of different regions of Israel and the Sinai Peninsula reveal two clusters of species. The first includes the Great Rift Valley and most parts of the Sinai Peninsula, and the second incorporates most regions of Israel together with Central Sinai Foothills. Five distinct adult phenological groups of tiger beetles can be distinguished in these two clusters: active all-year (three species), spring-fall (five species), summer (two species), spring-summer (one species) and spring (one species). The likely origins of the tiger beetle fauna of this area are presented. An annotated list and illustrated identification key of the Cicindelinae of Israel and adjacent lands are provided.

  3. Dating recent sediments from the subaqueous Yangtze Delta and adjacent continental shelf, China

    Directory of Open Access Journals (Sweden)

    Zhang-Hua Wang

    2014-04-01

    Full Text Available In this study we analyzed sediment lithology, fallout of 210Pb and 137Cs, and spheroidal carbonaceous particles (SCPs for two short cores, YZE and CX38, obtained by gravity corer from the Yangtze River mouth offshore and adjacent continental shelf, to compare geochronological methods on the recent sediments of this area. Lithology and grain size changes in YZE suggested the re-discharging of the North Channel of the Yangtze River mouth by flood events during 1949–1954 and associated accretion in the offshore area. This event was validated by a remarkable zone of declination in both 137Cs and 210Pb activities and the absolute ages derived from the 137Cs and SCPs. In contrast, 210Pb results show obvious disturbance of grain size by sediment mixing and cannot be interpreted above 100 cm. In CX38, absolute ages for the early- and mid-1950s were derived by the 137Cs and the SCP profile respectively, which occurred in a reasonable sequence. The excess 210Pb distribution shows exponentially decreasing activities with depth, and the mean sedimentation rate agrees roughly with the one inferred from the SCP profile. We suggest that the limitation of the 210Pb method needs consideration while the SCP profile has the potential to provide a useful and independent dating method for recent Yangtze offshore and adjacent shelf sediments.

  4. Local government units initiatives on coastal resource management in adjacent municipalities in Camarines Sur, Philippines

    Science.gov (United States)

    Faustino, A. Z.; Madela, H. L.

    2018-03-01

    This research was conducted to determine the local government units (LGUs) initiatives on coastal resource management (CRM) in adjacent municipalities in Camarines Sur, Philippines. The respondents of this study are 100 fisherfolk leaders in the municipalities of Calabanga, Tinambac and Siruma. Descriptive, comparative and evaluative methods of research were employed and a survey questionnaire was used as the primary tool in data gathering. On the test of difference, the computed F-value of 12.038 and p-value of .001 revealed a very high difference in the implementation of CRM initiatives in the adjacent municipalities. The respondents in this study live below the poverty threshold. The intrusion of commercial fishers and the use of active fishing gears inside the 15-km municipal waters significantly affect the marine habitat while fishpond conversion kills the natural cycle in the mangrove forests. However, the FOs membership in the Municipal Fisheries and Aquatic Resources Management Council empower them to engage in governance which can be a venue for them to recommend policies related to CRM. As a result of this study, a CRM monitoring and evaluation model was crafted to guide the LGUs in the review, revision and crafting of CRM programs.

  5. Screening of the residual normal ovarian tissue adjacent to orthotopic epithelial ovarian carcinomas in nude mice.

    Science.gov (United States)

    Zhu, G H; Wang, S T; Yao, M Z; Cai, J H; Chen, C Y; Yang, Z X; Hong, L; Yang, S Y

    2014-04-16

    The objective of this study was to explore the feasibility and methods of screening the residual normal ovarian tissue adjacent to orthotopic ovarian carcinomas in nude mice. Human epithelial ovarian cancer cells (OVCAR3) were subcutaneously implanted for a tumor source and ovarian orthotopic transplantation. The cancer tissue, proximal paraneoplastic tissue, middle paraneoplastic tissue, remote paraneoplastic tissue, and normal ovarian tissue were removed. CK-7, CA125, p53, survivin, MMP-2, and TIMP-2 expression was detected by reverse transcription polymerase chain reaction. We obtained 35 paraneoplastic residual ovarian tissues with normal biopsies from 40 cases of an orthotopic epithelial ovarian carcinoma model (87.5%). CK-7, CA125, p53, survivin, MMP-2, and TIMP-2 expression was lower in proximal paraneoplastic tissue than in cancer tissue (P tissue (P tissue as well as among residual normal ovarian tissues with different severity (P > 0.05). In ovarian tissues of 20 normal nude mice, the expression of CK- 7, CA125, p53, survivin, MMP-2, and TIMP-2 was negative. Overall, the expression levels of CK-7, CA125, p53, survivin, MMP-2, TIMP-2, and other molecular markers showed a decreasing trend in the non-cancer tissue direction. The expression levels can be used as standards to screen residual normal ovarian tissue. We can obtain relatively safe normal ovarian tissues adjacent to epithelial ovarian cancer.

  6. Spatial distribution of heavy metals in solid adjacent to the Naples-Salerno motor way

    International Nuclear Information System (INIS)

    Imperato, M.; Monetti, V.; Naimo, D.; Stanzione, D.

    1999-01-01

    This work analyses the distribution of heavy metal in soil adjacent to the Naples-Salerno motor way, an area which typically contains volcanic products from Somma-Vesuvio. The various concentrations of Pb, Cd, Zn, Mn, Cu and Cr found in different portions of the motor way (embankment, road cut, field level) are reported. The data obtained indicate high level of pollution in soil adjacent to the motor way fencing, with maximum concentrations of 1220 ppm Pb, 1.9 ppm Cd and 341 ppm Zn. Gradients of decreasing pollution with distance from the fencing and with altitude from the road surface are highest for Zn followed by Pb and Cd. The presence of these three materials in depth follows an averagely constant falling gradient, with minimum detected values at 50 cm depth. The spatial distribution of Cr does not reveal any significant differences. Relatively big levels are due to the presence in the soil of Chromium-rich minerals such as augite and olivine. Mn and Cu are found, due to local contribution, probably as a consequence of the use of copper compounds in agriculture [it

  7. Contralateral breast cancer adjacent to a fibroadenoma: report of a case.

    Science.gov (United States)

    Iwamoto, Miki; Takei, Hiroyuki; Iida, Shinya; Yamashita, Kouji; Yanagihara, Keiko; Kurita, Tomoko; Tsuchiya, Shinichi; Kanazawa, Yoshikazu; Uchida, Eiji

    2014-01-01

    A 64-year-old woman noticed a lump of the right breast and consulted our outpatient clinic. She had undergone multiple excisional biopsies of fibroadenomas in both breasts and mastectomy for invasive ductal carcinoma (IDC) of the left breast. After completing 5 years of treatment with adjuvant tamoxifen, she had undergone screening with annual physical examinations and occasional computed tomography. She was declared recurrence-free 13 years after breast cancer surgery, although lumps were detected in the right breast, probably due to fibroadenomas. Mammography, ultrasonography, and magnetic resonance imaging revealed that the lump was irregularly shaped, 2 cm in diameter, and adjacent to a fibroadenoma with macrocalcification. Two axillary lymph nodes were enlarged and suggestive of metastasis. A core needle biopsy revealed IDC of the right breast. She underwent a right partial mastectomy with axillary lymph node dissection. The IDC was 2 cm in diameter, of nuclear grade 2, and adjacent to a 0.7-cm fibroadenoma with a macrocalcification. The margins of the IDC close to the fibroadenoma were clearly demarcated by the fibrous capsule of the fibroadenoma. Four axillary lymph nodes were positive for metastasis. In the present case the presence of fibroadenoma might have interfered with the early detection of the contralateral IDC. The history of multiple excisions of fibroadenomas and mastectomy for breast cancer suggests an increased risk of contralateral breast cancer for the patient's entire life; therefore, regular annual follow-up, such as physical examinations and mammography, is recommended.

  8. Breast Cancer Arising Adjacent to an Involuting Fibroadenoma: Serial Changes in Radiologic Features

    Science.gov (United States)

    Park, Chae Jung; Kim, Eun-Kyung; Woo, Ha Young; Moon, Hee Jung; Yoon, Jung Hyun

    2015-01-01

    Fibroadenoma is a common benign breast lesion and its malignant transformation is rare. There have been several case reports and studies that retrospectively reviewed breast cancers that arose within fibroadenomas; however, none of these studies reported serial changes in radiologic features of the cancer, including findings from mammography and ultrasound (US). We report a case of breast cancer arising adjacent to an involuting fibro adenoma in a 39-year-old woman who was undergoing serial follow-up after her fibroadenoma was diagnosed. Seven years after her diagnosis, the lesion showed evidence of coarse calcifications, a typical sign of involution. Four years later, US revealed a newly developed hypoechoic lesion with irregular margins and peripherally located calcifications adjacent to the fibroadenoma. A core biopsy was performed, and histopathological examination resulted in a diagnosis of invasive ductal carcinoma. When new suspicious features are observed in a fibroadenoma, radiologists should raise the concern for breast cancer and proceed with diagnosis and treatment accordingly. PMID:26472981

  9. Regional Jurassic geologic framework of Alabama coastal waters area and adjacent Federal waters area

    Science.gov (United States)

    Mink, R.M.; Bearden, B.L.; Mancini, E.A.

    1989-01-01

    To date, numerous Jurassic hydrocarbon fields and pools have been discovered in the Cotton Valley Group, Haynesville Formation, Smackover Formation and Norphlet Formation in the tri-state area of Mississippi, Alabama and Florida, and in Alabama State coastal waters and adjacent Federal waters area. Petroleum traps are basement highs, salt anticlines, faulted salt anticlines and extensional faults associated with salt movement. Reservoirs include continental and marine sandstones, limestones and dolostones. Hydrocarbon types are oil, condensate and natural gas. The onshore stratigraphic and structural information can be used to establish a regional geologic framework for the Jurassic for the State coastal waters and adjacent Federal waters areas. Evaluation of the geologic information along with the hydrocarbon data from the tri-state area indicates that at least three Jurassic hydrocarbon trends (oil, oil and gas condensate, and deep natural gas) can be identified onshore. These onshore hydrocarbon trends can be projected into the Mobile area in the Central Gulf of Mexico and into the Pensacola, Destin Dome and Apalachicola areas in the Eastern Gulf of Mexico. Substantial reserves of natural gas are expected to be present in Alabama State waters and the northern portion of the Mobile area. Significant accumulations of oil and gas condensate may be encountered in the Pensacola, Destin Dome, and Apalachicola areas. ?? 1989.

  10. Optimal technique of linear accelerator-based stereotactic radiosurgery for tumors adjacent to brainstem.

    Science.gov (United States)

    Chang, Chiou-Shiung; Hwang, Jing-Min; Tai, Po-An; Chang, You-Kang; Wang, Yu-Nong; Shih, Rompin; Chuang, Keh-Shih

    2016-01-01

    Stereotactic radiosurgery (SRS) is a well-established technique that is replacing whole-brain irradiation in the treatment of intracranial lesions, which leads to better preservation of brain functions, and therefore a better quality of life for the patient. There are several available forms of linear accelerator (LINAC)-based SRS, and the goal of the present study is to identify which of these techniques is best (as evaluated by dosimetric outcomes statistically) when the target is located adjacent to brainstem. We collected the records of 17 patients with lesions close to the brainstem who had previously been treated with single-fraction radiosurgery. In all, 5 different lesion catalogs were collected, and the patients were divided into 2 distance groups-1 consisting of 7 patients with a target-to-brainstem distance of less than 0.5cm, and the other of 10 patients with a target-to-brainstem distance of ≥ 0.5 and linear accelerator is only 1 modality can to establish for SRS treatment. Based on statistical evidence retrospectively, we recommend VMAT as the optimal technique for delivering treatment to tumors adjacent to brainstem. Copyright © 2016 American Association of Medical Dosimetrists. All rights reserved.

  11. Node-pair reliability of network systems with small distances between adjacent nodes

    International Nuclear Information System (INIS)

    Malinowski, Jacek

    2007-01-01

    A new method for computing the node-pair reliability of network systems modeled by random graphs with nodes arranged in sequence is presented. It is based on a recursive algorithm using the 'sliding window' technique, the window being composed of several consecutive nodes. In a single step, the connectivity probabilities for all nodes included in the window are found. Subsequently, the window is moved one node forward. This process is repeated until, in the last step, the window reaches the terminal node. The connectivity probabilities found at that point are used to compute the node-pair reliability of the network system considered. The algorithm is designed especially for graphs with small distances between adjacent nodes, where the distance between two nodes is defined as the absolute value of the difference between the nodes' numbers. The maximal distance between any two adjacent nodes is denoted by Γ(G), where G symbolizes a random graph. If Γ(G)=2 then the method can be applied for directed as well as undirected graphs whose nodes and edges are subject to failure. This is important in view of the fact that many algorithms computing network reliability are designed for graphs with failure-prone edges and reliable nodes. If Γ(G)=3 then the method's applicability is limited to undirected graphs with reliable nodes. The main asset of the presented algorithms is their low numerical complexity-O(n), where n denotes the number of nodes

  12. Detection process of defects in a tube close to an adjacent element, especially in a heat exchanger

    International Nuclear Information System (INIS)

    Holt, A.E.; Wehrmeister, A.E.; Whaley, H.L.

    1978-01-01

    On-site process for obtaining, by Foucault currents, the indication of a defect in a tube close to an adjacent element masking the indication of the defect. It is characterized by the course of a reference tube with an eddy current sensor near a similar adjacent element in order to obtain an indication of reference eddy currents of the adjacent element first mentioned, the completion of a joint crossover of the above first mentioned tube so as to obtain a composite indication of eddy currents of the defect and of the adjacent element, and the generation of the indication by eddy currents of the defect by comparing the composite indication with the reference indication [fr

  13. The dehydration, rehydration and tectonic setting of greenstone belts in a portion of the northern Kaapvaal Craton, South Africa

    Science.gov (United States)

    Vanreenen, D. D.; Barton, J. M., Jr.; Roering, C.; Vanschalkwyk, J. C.; Smit, C. A.; Debeer, J. D.; Stettler, E. H.

    1986-01-01

    High-grade gneiss terranes and low-grade granite-greenstone terranes are well known in several Archaean domains. The geological relationship between these different crustal regions, however, is still controversial. One school of thought favors fundamental genetic differences between high-grade and low-grade terranes while others argue for a depth-controlled crustal evolution. The detailed examination of well-exposed Archaean terranes at different metamorphic grades, therefore, is not only an important source of information about the crustal levels exposed, but also is critical to the understanding of the possible tectonic and metamorphic evolution of greenstone belts with time. Three South African greenstone belts are compared.

  14. Oxigen isotope compositions as indicators of epidote granite genesis in the Borborema Provinces, NE Brazil

    International Nuclear Information System (INIS)

    Ferreira, V.P.; Valley, J.W; Sial, A.N; Spicuzza, M.J

    2001-01-01

    Neoproterozoic magmatic epidote-bearing granitoids intrude low-grade metapelites in the Cachoeirinha-Salgueiro terrane (CST), and gneisses and migmatites in the Serido terrane (ST), in the Borborema structural province, northeastern Brazil. Granitoids in both terranes contain biotite and hornblende, and are metaluminous, calc-alkalic, and oxidized I-type granites according to White's (1992) classification. However, in spite of these similarities, this work shows that mineral oxygen isotope data from plutons of the two terranes indicate different magma sources, and that magmatic epidote besides crystallizing at different pressure conditions, can have variable isotopic composition (au)

  15. Correlation between diagnostic capability of MR-mammography and histology of tissue adjacent to tumor

    Energy Technology Data Exchange (ETDEWEB)

    Takahara, Taro [St. Marianna Univ., Kawasaki, Kanagawa (Japan)

    1996-12-01

    The purpose of this paper is to evaluate correlation between the capability in the diagnosis of tumor extent and histology of adjacent tissue. MR-mammography (MRM) was obtained in twenty-one patients with surgically resected breast cancer by 0.5 T superconducting magnet (PHILIPS GY-ROSCAN T5-II, release 3.1). Pre and postcontrast 3D-spoiled gradient echo sequence were employed for MRM with spectral presaturation with inversion recovery (SPIR) and on-resonance MTC. The contrast determination time, the passing time of the center of k-space, was 1 min 50 s in 14 cases with key-hole imaging, and 2 min 46 s in 7 cases without key-hole imaging. Early enhancing area was considered as a tumor and an accuracy of tumor extent was evaluated by two radiologists. Accurate interpretation was obtained in 9 of 9 cases with atrophic mammary gland with fatty replacement and 3 of 3 cases with severe fibrosis in mammary gland. Seven cases were unclear in tumor margin due to intense enhancement of the adjacent tissue. One of 3 cases with normal mammary gland showed unclear margin of the tumor, which corresponded to the area of rich population of lobules in a young patient. Two of 2 cases of fibrocystic change with nonproliferative lesions in one case and proliferative lesions without atypia in another, showed unclear margin of tumor. Two cases of 2 intraductal spreading and 2 of 2 cases of massive interstitial invasion also showed unclear margin. The accuracy of tumor extent was found to have no correlation with either histology or enhancing ratio of the tumor. In conclusion, it is warranted to say that histology of adjacent tissue is an important factor to determine diagnostic capability of tumor extent by MRM. Fat replacement and fibrosis of the surrounding tissue are main causes of clear visualization of tumor, while normal mammary gland in young patients, fibrocystic change, intraductal spreading and invasion lead to the unclearness of tumor margin. (author)

  16. Correlation between diagnostic capability of MR-mammography and histology of tissue adjacent to tumor

    International Nuclear Information System (INIS)

    Takahara, Taro

    1996-01-01

    The purpose of this paper is to evaluate correlation between the capability in the diagnosis of tumor extent and histology of adjacent tissue. MR-mammography (MRM) was obtained in twenty-one patients with surgically resected breast cancer by 0.5 T superconducting magnet (PHILIPS GY-ROSCAN T5-II, release 3.1). Pre and postcontrast 3D-spoiled gradient echo sequence were employed for MRM with spectral presaturation with inversion recovery (SPIR) and on-resonance MTC. The contrast determination time, the passing time of the center of k-space, was 1 min 50 s in 14 cases with key-hole imaging, and 2 min 46 s in 7 cases without key-hole imaging. Early enhancing area was considered as a tumor and an accuracy of tumor extent was evaluated by two radiologists. Accurate interpretation was obtained in 9 of 9 cases with atrophic mammary gland with fatty replacement and 3 of 3 cases with severe fibrosis in mammary gland. Seven cases were unclear in tumor margin due to intense enhancement of the adjacent tissue. One of 3 cases with normal mammary gland showed unclear margin of the tumor, which corresponded to the area of rich population of lobules in a young patient. Two of 2 cases of fibrocystic change with nonproliferative lesions in one case and proliferative lesions without atypia in another, showed unclear margin of tumor. Two cases of 2 intraductal spreading and 2 of 2 cases of massive interstitial invasion also showed unclear margin. The accuracy of tumor extent was found to have no correlation with either histology or enhancing ratio of the tumor. In conclusion, it is warranted to say that histology of adjacent tissue is an important factor to determine diagnostic capability of tumor extent by MRM. Fat replacement and fibrosis of the surrounding tissue are main causes of clear visualization of tumor, while normal mammary gland in young patients, fibrocystic change, intraductal spreading and invasion lead to the unclearness of tumor margin. (author)

  17. Quantitative evaluation in enhancement of pancreas and adjacent vessels during spiral CT

    International Nuclear Information System (INIS)

    Kim, Hyoung Seuk; Shin, Kue Hee; Park, Cheol Min; Cha, Sang Hoon; Chung, Kyoo Byung

    1997-01-01

    To determine by quantitative evaluation of pancreatic and adjacent vascular enhancement during spiral CT, the ideal scan delay for examination of the pancreas. Dual(n=3D90) and triple(n=3D90) phase spiral CT scans of patients whose pancreas showed no pathologic condition were retrospectively evaluated. Dual-phase scans were performed at 43 seconds(early), and 5-6 minutes(delayed) after the injection of 120ml of contrast material at an injection rate of 3ml/sec;triple-phase scans were performed at 25 seconds(arterial),60-65 seconds (portal) and 5-6 minutes (delayed) after the injection of 120-140ml of contrast material at an injection rate of 2-4ml/sec, and ten patients also underwent precontrast scanning. CT attenuation values(HU) were measured in the head, body and tail of the pancreas, aorta, and main portal vein during each phase of all scans. Triple-phase protocol was used to measure the effect of different total volumes and injection rates on enhancement of the pancreas and adjacent vessels. There was no significant difference in the degree of enhancement of the pancreas head, body and tail during each phase(p>0.05). The pancreas was maximally enhanced on 43 second delayed scan(132±20HU)(p 0.05). The main portal vein showed maximum enhancement on 43-second delayed scan(207±44HU)(p<0.05). Different total volume of contrast material did not change the enhancement of the pancreas and adjacent vessels. At an injection rate of 2ml/sec, peak enhancement of the pancreas, aorta and portal vein was obtained on 60-65 second delayed scan, and at 4ml/sec, peak enhancement was obtained on 25 second delayed scan(p<0.05). Observing the usual protocols for abdominal spiral CT scanning, the pancreas was most effectively evaluated using a 43-second delayed scan. An increased injection rate resulted in earlier enhancement of the pancreas, aorta and portal vein

  18. Petrography and geochronology (U/Pb-Sm/Nd) the Passagem Granite, Pensamiento Granitoid Complex, Paragua Terrane, SW Amazon Craton, Mato Grosso, Brazil; Petrologia e geocronologia (U/Pb-Sm/Nd) do Granito Passagem, Complexo Granitoide Pensamiento, SW do Craton Amazonico (MT)

    Energy Technology Data Exchange (ETDEWEB)

    Jesus, Gisely Carmo de, E-mail: giselycarmo@hotmail.co [Universidade Federal de Mato Grosso (ICET/UFMT), Cuiaba, MT (Brazil). Inst. de Ciencias Exatas e da Terra. Programa de Pos-Graduacao em Geociencias; Sousa, Maria Zelia Aguiar de, E-mail: mzaguiar@terra.com.b [Universidade Federal de Mato Grosso(ICET/UFMT), Cuiaba, MT (Brazil). Inst. de Ciencias Exatas e da Terra. Dept. de Recursos Minerais; Ruiz, Amarildo Salina; Matos, Joao Batista de, E-mail: asruiz@gmail.co, E-mail: jmatos@cpd.ufmt.b [Universidade Federal de Mato Grosso (ICET/UFMT), Cuiaba, MT (Brazil). Inst. de Ciencias Exatas e da Terra. Dept. de Geologia Geral

    2010-09-15

    The Passagem granite includes stocks, plugs and dikes located in the Ricardo Franco hill - Vila Bela da Santissima Trindade region - state of Mato Grosso, central Brazil. The Passagem Granite is included in the Paragua terrane - SW Amazonian Craton. It consists of isotropic monzogranite, sienogranite and more rarely granodiorites with leucocratic dark gray to white color. These rocks range from hypidomorphic inequigranular to xenomorphic texture, fine to medium grained. Biotite is the only primary mafic present as essential phase and characterize an expanded slightly acid sequence formed by a sub-alkaline magmatism of high-potassium calc-alkaline, slightly peraluminous composition from arc magmatic tectonic environment during a post-collisional period. Mechanism of fractional crystallization of plagioclase, biotite, titanite, apatite and zircon associated with simultaneous crustal assimilation are suggested for the evolution of these rocks. The results support the hypothesis of a post-collisional magmatism in the Paragua terrane at 1284 +- 20 Ma corresponding to the crystallization age of the Passagem granite. This paper propose that Passagem Granite represents as an extension in Brazilian terrane of the Pensamiento Granitoid Complex. (author)

  19. Interaction of the nucleation phenomena at adjacent sites in nucleate boiling

    International Nuclear Information System (INIS)

    Sultan, M.; Judd, R.L.

    1983-01-01

    The present investigation is an original study in nucleate pool boiling heat transfer combining theory and experiment in which water boiling at atmospheric pressure on a single copper surface at two different levels of heat and different levels of subcooling was studied. Cross spectral analysis of the signals generated by the emission of bubbles at adjacent nucleation sites was used to determine the relationship of the time elapsed between the start of bubble growth at the two neighbouring active sites with the distance separating them. The experimental results obtained indicated that for the lower level of heat flux at three different levels of subcooling, the elapsed time and distance were directly related. Theoretical predictions of a temperature disturbance propagating through the heating surface in the radial direction gave good agreement with the experimental findings, suggesting that this is the mechanism responsible for the activation of the surrounding nucleation sites

  20. Influence of road salting on the adjacent Norway spruce (Picea abies) forest

    International Nuclear Information System (INIS)

    Forczek, S.T.; Benada, O.; Kofronova, O.; Sigler, K.; Matucha, M.

    2011-01-01

    Winter deicing and traffic spreads salt to road-adjacent Norway spruce trees in the form of spraying and salt slops. Our use of Na36Cl revealed roots as the main pathway of salt uptake. One-shot application of a concentrated Na36Cl solution to spruce saplings by both irrigation and spraying causes macroscopic damage to the needles and affects the needle phyllosphere. Irrigation affects the trees more than spraying because Cl uptake through roots is faster and eventually leads to higher chloride content in the plant. Along with the root-needle route, spray-deposited chloride from the needles is re-transported back into the soil and again taken up by roots to needles

  1. The dynamics of spiral tip adjacent to inhomogeneity in cardiac tissue

    Science.gov (United States)

    Zhang, Juan; Tang, Jun; Ma, Jun; Luo, Jin Ming; Yang, Xian Qing

    2018-02-01

    Rotating spiral waves in cardiac tissue are implicated in life threatening cardiac arrhythmias. Experimental and theoretical evidences suggest the inhomogeneities in cardiac tissue play a significant role in the dynamics of spiral waves. Based on a modified 2D cardiac tissue model, the interaction of inhomogeneity on the nearby rigidly rotating spiral wave is numerically studied. The adjacent area of the inhomogeneity is divided to two areas, when the initial rotating center of the spiral tip is located in the two areas, the spiral tip will be attracted and anchor on the inhomogeneity finally, or be repulsed away. The width of the area is significantly dependent on the intensity and size of the inhomogeneity. Our numerical study sheds some light on the mechanism of the interaction of inhomogeneity on the spiral wave in cardiac tissue.

  2. Internal calibration on adjacent samples (InCAS) with Fourier transform mass spectrometry.

    Science.gov (United States)

    O'Connor, P B; Costello, C E

    2000-12-15

    Using matrix-assisted laser desorption/ionization (MAL DI) on a trapped ion mass spectrometer such as a Fourier transform mass spectrometer (FTMS) allows accumulation of ions in the cell from multiple laser shots prior to detection. If ions from separate MALDI samples are accumulated simultaneously in the cell, ions from one sample can be used to calibrate ions from the other sample. Since the ions are detected simultaneously in the cell, this is, in effect, internal calibration, but there are no selective desorption effects in the MALDI source. This method of internal calibration with adjacent samples is demonstrated here on cesium iodide clusters, peptides, oligosaccharides, poly(propylene glycol), and fullerenes and provides typical FTMS internal calibration mass accuracy of < 1 ppm.

  3. Hydrothermal manganese oxide deposits from the Izu-Ogasawara (Bonin)-Mariana Arc and adjacent areas

    Energy Technology Data Exchange (ETDEWEB)

    Usui, A.; Nishimura, A. (Geological Survey of Japan, Tsukuba (Japan))

    1992-04-27

    Modern and fossil hydrothermal manganese oxide deposits were discovered from a number of locations in the Izu-Ogasawara(Bonin)-Mariana Arc and adjacent areas during the Hakurei-Maru cruises from 1984 to 1989. This paper describes the occurrence and characteristics of these manganese deposits and their geological significance. It was found that the mineralogical and chemical composition and microstructure of the deposits are typically different from manganese nodules and crusts of hydrogenetic or diagenetic origin. Hardpans, veinlets, sheets, and irregular mass of the hydrothermal manganese deposits often cover a large area of sea bed, which suggests possible high-temperature hydrothermal sulfide deposits in their vicinity. On the other hand, the manganese minerals sometimes occur as substrate of younger hydrogenetic crusts and as nucleus of hydrogenetic nodules, which can provide a geological history of low-temperature hydrothermal activity on the past island arcs. 45 refs., 19 figs., 3 tabs.

  4. Transport of mecoprop from agricultural soils to an adjacent salt marsh

    International Nuclear Information System (INIS)

    Fletcher, Caroline A.; Scrimshaw, Mark D.; Lester, John N.

    2004-01-01

    Salt marshes are important ecological areas and play a significant role in coastal flood defence schemes. In many areas of the UK they are adjacent to agricultural areas utilised for the growth of cereal crops, for which mecoprop is used as a selective herbicide in the control of broad-leafed weeds. This study measured concentrations of mecoprop in soils, drainage ditch waters and sediments and salt marsh sediments over a period of 138 days following spring application. Soil concentrations of up to 1827 μg/g were recorded after application, which demonstrated a half life for mecoprop of from 9 to 12 days, with first order kinetics. However, a major rainfall event 9 days after application resulted in significant transport of herbicide to the salt marsh via subsurface field drains, drainage ditches and discharge sluice. Mecoprop concentrations of up to 386 μg/l observed in water samples were above UK guidelines

  5. Norway and adjacent sedimentary basins during Cenozoic times - sediment fluxes, accumulation rates and mass balance

    DEFF Research Database (Denmark)

    Gołędowski, Bartosz; Nielsen, S.B.; Clausen, O.R.

    2011-01-01

    use offshore data from adjacent sedimentary basins (the North Sea and the Norwegian shelf) to calculate the amount of erosion. We have used a broad dataset of seismic 2D lines to map depositional units and a well dataset for the stratigraphic control and the velocity distribution in the sediments. We...... have therefore obtained accumulation rates in meters per million years for 5 depositional units in three areas - Southern North Sea, Central and Northern North Sea and the Norwegian shelf. Furthermore, taking into account the decay of porosity in sediments with burial depth, we have estimated...... the sediment volumes at the time of their deposition. Such calculation gives minimum values of erosion rates onshore and a mass balance can be approximated, when considering uncertainties like deposition of sediments outside study area, post-depositional sediment removal and loss of mass due to chemical...

  6. SOIL AND “CERRADO” TREES NUTRIENTS AND METALS IN ADJACENT SANITARY LANDFILL AREA

    Directory of Open Access Journals (Sweden)

    Otacílio Antunes Santana

    2008-09-01

    Full Text Available This research verified the influence of a Sanitary Landfill located at the Jockey Club of the Brasilia City (JCB on the chemical contents in the tree species of “Cerrado”. Six 25 x 500 m blocks were established in the PNB to sample the soil and the trees to chemical analysis. Three blocks were established near the landfill area and three in the control area. Nitrogen, phosphorus, potassium, calcium, lead, chromium, copper and mercury were analyzed. The highest nutrients and metals concentrations in soil were sampled in landfill adjacent area. The significant, crescent and directly proportional relationship (R2 > 0.80; p < 0.001 were observed between the elements concentration analyzed in soil with the leaves tissues. Therefore, the studied landfill presences increased nutrients and metals concentrations in soil and leaf tissue, fact that did not occur in the control area.

  7. Species richness and distribution of chondrichthyan fishes in the Arctic Ocean and adjacent seas

    DEFF Research Database (Denmark)

    Lynghammar, A.; Christiansen, J. S.; Mecklenburg, C. W.

    2013-01-01

    The sea ice cover decreases and human activity increases in Arctic waters. Fisheries and bycatch issues, shipping and petroleum exploitation (pollution issues) make it imperative to establish biological baselines for the marine fishes inhabiting the Arctic Ocean and adjacent seas (AOAS). Species...... richness, zoogeographic affiliations and Red List statuses among chondrichthyan fishes (Chondrichthyes) were examined across 16 AOAS regions as a first step towards credible conservation actions. Published literature and museum vouchers were consulted for presence/absence data. Although many regions...... are poorly sampled, 49 chondrichthyan species have been reported from the AOAS. Skates and rays are the most species-rich taxon, represented by 27 species in family Rajidae and one species in family Dasyatidae. The sharks comprise 20 species in 13 families and the chimaeras one species in family Chimaeridae...

  8. Thermal non-equilibrium in porous medium adjacent to vertical plate: ANN approach

    Science.gov (United States)

    Ahmed, N. J. Salman; Ahamed, K. S. Nazim; Al-Rashed, Abdullah A. A. A.; Kamangar, Sarfaraz; Athani, Abdulgaphur

    2018-05-01

    Thermal non-equilibrium in porous medium is a condition that refers to temperature discrepancy in solid matrix and fluid of porous medium. This type of flow is complex flow requiring complex set of partial differential equations that govern the flow behavior. The current work is undertaken to predict the thermal non-equilibrium behavior of porous medium adjacent to vertical plate using artificial neural network. A set of neurons in 3 layers are trained to predict the heat transfer characteristics. It is found that the thermal non-equilibrium heat transfer behavior in terms of Nusselt number of fluid as well as solid phase can be predicted accurately by using well-trained neural network.

  9. A method for opening a mine field which is adjacent to a pit

    Energy Technology Data Exchange (ETDEWEB)

    Onishchenko, V.I.; Grebenyuk, V.K.; Kukharev, V.N.; Martynenko, V.P.; Omelnitskiy, A.G.; Sallin, V.I.; Sidorov, A.S.

    1982-01-01

    The method for opening a mine field adjacent to a pit includes the construction of the main and auxiliary opening drifts in the pit and the surface complex of the mine through assembling a support with subsequent filling of them by tailings of the covering rock. In order to increase the productive capacity of the mine, to reduce capital expenditures and to increase the safety of underground operations, a base is first formed from the tailing rock along the front of the open mining operations, from the bottom of the pit at the level of the stratum being opened to the surface with simultaneous layer by layer packing of the cited base, after which the opening drifts are built on this base. The mouth of the main opening drifts and the surface complex of the mine are positioned in the region of the pit.

  10. Influence of a Brazilian sewage outfall on the toxicity and contamination of adjacent sediments

    Science.gov (United States)

    Abessa, D.M.S.; Carr, R.S.; Rachid, B.R.F.; Sousa, E.C.P.M.; Hortelani, M.A.; Sarkis, J.E.

    2005-01-01

    The submarine sewage outfall of Santos (SSOS) is situated in the Santos Bay (São Paulo, Brazil) and is potentially a significant source of contaminants to the adjacent marine ecosystem. The present study aimed to assess the influence of SSOS on the sediment toxicity and contamination at Santos Bay. At the disposal site, sediments tended to be finer, organically richer and exhibited higher levels of surfactants and metals, sometimes exceeding the “Threshold Effect Level” values. The SSOS influence was more evident toward the East, where the sediments exhibited higher levels of TOC, total S and metals during the summer 2000 sampling campaign. Sediment toxicity to amphipods was consistently detected in four of the five stations studied. Amphipod survival tended to correlate negatively to Hg, total N and % mud. This work provides evidence that the SSOS discharge affects the quality of sediments from Santos Bay, and that control procedures are warranted.

  11. Estuarine Human Activities Modulate the Fate of Changjiang-derived Materials in Adjacent Seas

    Science.gov (United States)

    WU, H.

    2017-12-01

    Mega constructions have been built in many river estuaries, but their environmental consequences in the adjacent coastal oceans were often overlooked. This issue was addressed with an example of the Changjiang River Estuary, which was recently built with massive navigation and reclamation constructions in recent years. Based on the model validations against cruises data and the numerical scenario experiments, it is shown that the estuarine constructions profoundly affected the fates of riverine materials in an indeed large offshore area. This is because estuarine dynamics are highly sensitive to their bathymetries. Previously, the Three Gorges Dam (TGD) was thought to be responsible for some offshore environmental changes through modulating the river plume extension, but here we show that its influences are secondary. Since the TGD and the mega estuarine constructions were built during the similar period, their influences might be confused.

  12. Bibliography of geologic studies: Columbia Plateau (Columbia River Basalt) and adjacent areas in Idaho

    International Nuclear Information System (INIS)

    Strowd, W.

    1978-11-01

    The objective of this compilation is to present a comprehensive listing of published, unpublished, and open-file references pertaining to the geology of the Columbia Plateau and adjacent areas in the State of Idaho. The bibliography was compiled in support of Rockwell's Basalt Waste Isolation Program that is evaluating the feasibility of nuclear waste storage in the Columbia River Basalt Group. The emphasis is on stratigraphy, structural geology, seismicity, and tectonics, although the nature of Columbia River Basalt distribution in Idaho has necessitated the inclusion of a sizeable collection of references on geology marginal to the Columbia Plateau and associated mineral resources. The bibliography is divided into two major sections, the alphabetical listing of all references and the subject index. The subject index is divided into 19 categories to facilitate locating a specific reference in the user's field of interest

  13. Energy Deposition in Adjacent LHC Superconducting Magnets from Beam Loss at LHC Transfer Line Collimators

    CERN Document Server

    Beavan, S; Kain, V

    2006-01-01

    Injection intensities for the LHC are over an order of magnitude above the damage threshold. The collimation system in the two transfer lines is designed to dilute the beam sufficiently to avoid damage in case of accidental beam loss or mis-steered beam. To maximise the protection for the LHC most of the collimators are located in the last 300 m upstream of the injection point where the transfer lines approach the LHC machine. To study the issue of possible quenches following beam loss at the collimators part of the collimation section in one of the lines, TI 8, together with the adjacent part of the LHC has been modeled in FLUKA. The simulated energy deposition in the LHC for worst-case accidental losses and as well as for losses expected during a normal filling is presented.

  14. Florisitic summary of 'Manual of Vascular Plants of Northeastern United States and Adjacent Canada', second edition

    Science.gov (United States)

    Bennett, J.P.

    1996-01-01

    The second edition of the Manual of Vascular Plants of Northeastern United States and Adjacent Canada by Gleason and Cronquist (1991) is the most recent and up-to-date taxonomic treatment of the flora of that region. Since no floristic summary of the Manual was included in the publication, a computer analysis of the taxonomic data of the Manual was performed in order to generate a floristic summary. Totals of 4285 species, 1091 genera, and 191 families were tabulated. The largest genus was Carex, with 230 species; the largest family was the Asteraceae, with 528 species. Comparisons made with earlier floras of the same region indicated small declines on the order of 10% for these taxonomic groups.

  15. Bone reactions adjacent to titanium implants subjected to static load. A study in the dog (I)

    DEFF Research Database (Denmark)

    Gotfredsen, K; Berglundh, T; Lindhe, J

    2001-01-01

    The aim of the study was to evaluate the effect of lateral static load induced by an expansion force on the bone/implant interface and adjacent peri-implant bone. In 3 beagle dogs, the 2nd, 3rd and 4th mandibular premolars were extracted bilaterally. Twelve weeks later 8 implants of the ITI Dental...... Implant System were placed in each dog. Crowns connected in pairs were screwed on the implants 12 weeks after implant installation. The connected crowns contained an orthodontic expansion screw yielding 4 loading units in each dog. Clinical registrations, standardized radiographs and fluorochrome labeling...... were carried out during the 24-week loading period. Biopsies were harvested and processed for ground sectioning. The sections were subjected to histological examination. No evident marginal bone loss was observed at either test or control sites. The bone density and the mineralized bone-to-implant...

  16. Economic importance of oleoresin (Dipterocarpus alatus) to forest-adjacent households in Cambodia

    DEFF Research Database (Denmark)

    Dyrmose, Anne-Mette Hüls; Turreira Garcia, Nerea; Theilade, Ida

    2017-01-01

    interviewed and 100 resin trees were measured to examine factors affecting resin productivity. Forest-adjacent households were highly dependent on resin extraction for cash income. Households spent an average of 105 days annually on resin extraction. The mean annual household gross-income derived from liquid...... resin was USD 3,236. Solid resin contributed only a small part of household incomes except for the most remote and isolated village, Spong, in which solid resin contributed significantly to the gross-income. Resin trees yielded an average of 18 liters of oleoresin per year according to interview......The genus Dipterocarpus is the main source of marketable liquid oleoresin, which is important as a source of income for forest communities in Southeast Asia. However, deforestation and illegal as well as legal logging pose a threat to resin yielding species (Dipterocarpus spp.). There is still more...

  17. Gibbs Energy Modeling of Digenite and Adjacent Solid-State Phases

    Science.gov (United States)

    Waldner, Peter

    2017-08-01

    All sulfur potential and phase diagram data available in the literature for solid-state equilibria related to digenite have been assessed. Thorough thermodynamic analysis at 1 bar total pressure has been performed. A three-sublattice approach has been developed to model the Gibbs energy of digenite as a function of composition and temperature using the compound energy formalism. The Gibbs energies of the adjacent solid-state phases covelitte and high-temperature chalcocite are also modeled treating both sulfides as stoichiometric compounds. The novel model for digenite offers new interpretation of experimental data, may contribute from a thermodynamic point of view to the elucidation of the role of copper species within the crystal structure and allows extrapolation to composition regimes richer in copper than stoichiometric digenite Cu2S. Preliminary predictions into the ternary Cu-Fe-S system at 1273 K (1000 °C) using the Gibbs energy model of digenite for calculating its iron solubility are promising.

  18. [Characteristics of ichthyoplankton assemblages in Yangtze Estuary and adjacent waters in spring].

    Science.gov (United States)

    Liu, Shu-De; Xian, Wei-Wei; Liu, Dong

    2008-10-01

    Based on the investigation data of ichthyoplankton assemblages and environmental factors in Yangtze Estuary and adjacent waters in May 1999 and 2001, the characteristics of ichthyoplankton assemblages in these areas in spring were studied by using TWINSPAN (two-way indicator species analysis) and CCA (canonical correspondence analysis). A total of 11 540 ichthyoplankton individuals were taxonomically identified, belonging to 11 orders, 18 families and 32 species, of which, Coilia mystus, Engraulis japonicus, Chaeturichthys hexanema, Allanetta bleekeri, and Trachidermis fasciatus were the dominant species. The ichthyoplankton communities were classified into three assemblages by using TWINSPAN, i.e., estuarine assemblage dominated by C. mystus, coastal assemblage dominated by A. bleekeri and T. fasciatus; and shelf assemblage featured by E. japonicus and C. hexanema. The CCA ordination of the interrelations among the three assemblages and their correlations to the environmental variables revealed that salinity, depth, dissolved oxygen, and total suspended particulate matter were the major factors affecting the ichthyoplankton assemblages in the study areas.

  19. Metal speciation in agricultural soils adjacent to the Irankuh Pb-Zn mining area, central Iran

    Science.gov (United States)

    Mokhtari, Ahmad Reza; Roshani Rodsari, Parisa; Cohen, David R.; Emami, Adel; Dehghanzadeh Bafghi, Ali Akbar; Khodaian Ghegeni, Ziba

    2015-01-01

    Mining activities are a significant potential source of metal contamination of soils in surrounding areas, with particular concern for metals dispersed into agricultural area in forms that are bioavailable and which may affect human health. Soils in agricultural land adjacent to Pb-Zn mining operations in the southern part of the Irankuh Mountains contain elevated concentrations for a range of metals associated with the mineralization (including Pb, Zn and As). Total and partial geochemical extraction data from a suite of 137 soil samples is used to establish mineralogical controls on ore-related trace elements and help differentiate spatial patterns that can be related to the effects of mining on the agricultural land soils from general geological and environmental controls. Whereas the patterns for Pb, Zn and As are spatially related to the mining operations they display little correlation with the distribution of secondary Fe + Mn oxyhydroxides or carbonates, suggesting dispersion as dust and in forms with limited bioavailability.

  20. Stock structure of Atlantic herring Clupea harengus in the Norwegian Sea and adjacent waters

    DEFF Research Database (Denmark)

    Pampoulie, Christophe; Slotte, Aril; Oskarsson, Guomundur J.

    2015-01-01

    The genetic structure of Atlantic herring Clupea harengus L. was investigated in its north-easterly distribution in the Norwegian Sea and adjacent waters, using 23 neutral and one non-neutral (Cpa111) microsatellite loci. Fish from the suspected 2 main populations-the Norwegian spring......-spawning herring (NSSH) and the Icelandic summer-spawning herring (ISSH)-were collected at spawning locations in their respective spawning seasons from 2009 to 2012. Samples were also collected from Norwegian autumn spawning locations, from different local Norwegian fjords such as the inner part...... of Trondheimsfjorden, Lindas pollene, Landvikvannet and Lusterfjorden, as well as from suspected Faroese spawning components. The observed level of genetic differentiation was significant but low (F-ST = 0.007) and mostly attributable to the differentiation of the local Norwegian fjord populations. The locus Cpa111...

  1. [Clinics adjacent to private pharmacies in Mexico: infrastructure and characteristics of the physicians and their remuneration].

    Science.gov (United States)

    Díaz-Portillo, Sandra P; Idrovo, Álvaro J; Dreser, Anahí; Bonilla, Federico R; Matías-Juan, Bonifacia; Wirtz, Veronika J

    2015-01-01

    To analyze and compare the physicians' characteristics, their remuneration, the compliance with regulation and the services offered between clinics adjacent to pharmacies (CAF) and independent medical clinics (CMI). Questionnaire applied to 239 physicians in 18 states including the Federal District, in Mexico in 2012. Physicians in CAF had less professional experience (5 versus 12 years), less postgraduate studies (61.2 versus 81.8%) and lower average monthly salaries (USD 418 versus USD 672) than their peers in CMI. In CAF there was less compliance in relation to medical record keeping and prescribing. The employment situation of physicians in CAF is more precarious than in CMI. It is necessary to strengthen the enforcement of existing regulations and develop policies according to the monitoring of its performance, particularly, but not exclusively, in CAF.

  2. Filler-depletion layer adjacent to interface impacts performance of thermal interface material

    Directory of Open Access Journals (Sweden)

    Susumu Yada

    2016-01-01

    Full Text Available When installing thermal interface material (TIM between heat source and sink to reduce contact thermal resistance, the interfacial thermal resistance (ITR between the TIM and heat source/sink may become important, especially when the TIM thickness becomes smaller in the next-generation device integration. To this end, we have investigated ITR between TIM and aluminum surface by using the time-domain thermoreflectance method. The measurements reveal large ITR attributed to the depletion of filler particles in TIM adjacent to the aluminum surface. The thickness of the depletion layer is estimated to be about 100 nm. As a consequence, the fraction of ITR to the total contact thermal resistance becomes about 20% when the TIM thickness is about 50 μm (current thickness, and it exceeds 50% when the thickness is smaller than 10 μm (next-generation thickness.

  3. Aerial surveys of seals at Rødsand seal sanctuary and adjacent haul-out sites

    DEFF Research Database (Denmark)

    Teilmann, J.; Dietz, R.; Edren, Susi M.C.

    This report describes the preliminary results of aerial surveys at Rødsand seal sanctuary, southeast Denmark and adjacent seal haul-out sites in southwestern Baltic. The work was carried out in connection with studies of potential effects of the Nysted offshore wind farm. Rødsand seal sanctuary...... is a part of seal management area 4, and the area is believed to hold a more or less closed population with little exchange to other areas. Although the harbour seal is relatively stationary there may be movements between the haul-out sites in the area. A possible reaction to disturbance from...... the construction and operation of the wind farm may be that the seals use other haul-out sites to a higher extend....

  4. Seasonality of pathogenic fungi in mites of rubber tree plantations adjacent to fragments of Cerrado

    Directory of Open Access Journals (Sweden)

    PR. Demite

    Full Text Available Fungi are the most frequently observed pathogens of mite populations, helping to control them on different crops. Twenty-five samples of leaves were collected from rubber tree plantations adjacent to two fragments of Cerrado vegetation. Each rubber tree plantation had 25 plants selected for sampling and seven leaves from around each tree top were collected up to seven to eight meters above ground. Approximately 250 individuals of Calacarus heveae Feres, Phyllocoptruta seringueirae Feres, and Tenuipalpus heveae Baker, collected randomly, were mounted from each plantation. Hirsutella thompsoni Fisher was observed on all three mites and T. heveae was the most infected species. The highest infestation levels occurred from November to February (rainy season. In the dry season, infestation levels were below 5%. Hirsutella thompsonii has potential to be used as mycoacaricide during the rainy season.

  5. Ambiguities in the elastic scattering of 8 MeV neutrons from adjacent nuclei

    International Nuclear Information System (INIS)

    Smith, A.B.; Lawson, R.D.; Guenther, P.T.

    1989-10-01

    Ratios of the cross sections for elastic scattering of 8 MeV neutrons from adjacent nuclei are measured over the angular range ∼20 degree - 160 degree for the target pairs 51 V/Cr, 59 Co/ 58 Ni, Cu/Zn, 89 Y/ 93 Nb, 89 Y/Zr, 93 Nb/Zr, In/Cd and 209 Bi/Pb. The observed ratios vary from unity by as much as a factor of ∼2 at some angles for the lighter target pairs. Approximately half the measured ratios are reasonably explained by a simple spherical optical model, including size and isospin contributions. In all cases, the geometry of the real optical--model potential is essentially the same for neighboring nuclei, and the real--potential strengths are consistent with the Lane model. In contrast, it is found that the imaginary potential may be quite different for adjacent nuclei, and the nature of this difference is examined. It is shown that the spin--spin interaction has a negligible effect on the calculation of the elastic--scattering ratios, but that channel coupling, leading to a large reorientation of the target ground state, can be a consideration, particularly in the 59 Co/ 58 Ni case. In the A ∼ 50--60 region the calculated ratios are sensitive to spin--orbit effects, but the exact nature of this interaction must await more definitive polarization measurements. The measured and calculated results suggest that the concept of a conventional ''global'' or even ''regional'' optical potential provides no more than a qualitative representation of the physical reality for a number of cases. 48 refs., 14 figs., 3 tabs

  6. Ambiguities in the elastic scattering of 8 MeV neutrons from adjacent nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.B.; Lawson, R.D.; Guenther, P.T.

    1989-10-01

    Ratios of the cross sections for elastic scattering of 8 MeV neutrons from adjacent nuclei are measured over the angular range {approx}20{degree} {minus} 160{degree} for the target pairs {sup 51}V/Cr, {sup 59}Co/{sup 58}Ni, Cu/Zn, {sup 89}Y/{sup 93}Nb, {sup 89}Y/Zr, {sup