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Sample records for younger granite intrusion

  1. Emplacement mechanisms and structural influences of a younger granite intrusion into older wall rocks - a principal study with application to the Goetemar and Uthammar granites. Site-descriptive modelling SDM-Site Laxemar

    International Nuclear Information System (INIS)

    The c. 1.80 Ga old bedrock in the Laxemar-Simpevarp area, which is the focus of the site investigation at Oskarshamn, is dominated by intrusive rocks belonging to the c. 1.86-1.65 Ga Transscandinavian Igneous Belt (TIB). However, the site investigation area is situated in between two c. 1.45 Ga old anorogenic granites, the Goetemar granite in the north and the Uthammar granite in the south. This study evaluates the emplacement mechanism of these intrusions and their structural influence on the older bedrock. Field observations and structural measurements indicate that both the Goetemar and the Uthammar granites are discordant and have not imposed any significant ductile deformation on their wall-rocks. The apparent conformity of geological contacts and fabrics in the wall rocks and the southern margin of the Goetemar granite is coincidental and inherited from the pattern of Svecokarelian deformation of the TIB. However, interpretation of regional aeromagnetic data suggests that the granites occur within a broad, NNE-SSW trending linear belt, pointing to deep seated tectonic control on their generation, ascent and emplacement. Thermochronology indicates that the granites were emplaced at depths between 4 and 8 km into brittle wall rocks. The 3-D shape of the Goetemar and Uthammar plutons has been investigated by 2.75D forward modelling of the residual gravity anomalies due to both granites. Both granites are associated with strong residual gravity anomalies of up to -10 mgal. Constraints on the geometry of the plutons at the surface are provided from surface geology maps and several deep boreholes located on or close to the model profiles. A further variable in the gravity modelling is introduced by either allowing the upper contact of the plutons to assume the most suitable orientation to produce the best fit between the modelled and observed gravity ('unconstrained models') or by forcing the near surface orientation of the contacts to be vertical ('constrained models'). The unconstrained model profiles for both plutons are characterized by gently outward dipping upper contacts to depths ?1 km, gently inward dipping lower contacts and a thin, centrally located root extending to depths of 5 to 10 km. However, this geometry is not supported by available boreholes, which do not penetrate the upper contact of the Goetemar pluton as predicted by the models. The constrained models are consistent with borehole data. They characterize the plutons as having vertical contacts in the upper 500 to 1,000 m, a 1,000 to 1,500 m thick mid-level body with outward dipping upper and horizontal and lower contacts, respectively, and broad roots extending to depths of ?4 km. Preliminary observations and gravity modelling results indicate that the Goetemar and Uthammar granites are discordant plutons with geometries most consistent with punched laccoliths, with some modification due to floor subsidence due to root development. Their vertical and lateral dimensions fall in the upper range for laccoliths and lower range for plutons as defined by recent data compilations. Their emplacement required elastic bending and eventual failure of roof rocks that was likely accompanied by reactivation of pre-existing fractures and shear zones and possibly the creation of new brittle fractures. Cooling and crystallization of the granites resulted in thermal resetting of the wall rocks and the establishment of a transient hydrothermal system, now recorded by fracture filling mineral assemblages

  2. Emplacement mechanisms and structural influences of a younger granite intrusion into older wall rocks - a principal study with application to the Goetemar and Uthammar granites. Site-descriptive modelling SDM-Site Laxemar

    Energy Technology Data Exchange (ETDEWEB)

    Cruden, Alexander R. (Dept. of Geology, Univ. of Toronto (Canada))

    2008-12-15

    The c. 1.80 Ga old bedrock in the Laxemar-Simpevarp area, which is the focus of the site investigation at Oskarshamn, is dominated by intrusive rocks belonging to the c. 1.86-1.65 Ga Transscandinavian Igneous Belt (TIB). However, the site investigation area is situated in between two c. 1.45 Ga old anorogenic granites, the Goetemar granite in the north and the Uthammar granite in the south. This study evaluates the emplacement mechanism of these intrusions and their structural influence on the older bedrock. Field observations and structural measurements indicate that both the Goetemar and the Uthammar granites are discordant and have not imposed any significant ductile deformation on their wall-rocks. The apparent conformity of geological contacts and fabrics in the wall rocks and the southern margin of the Goetemar granite is coincidental and inherited from the pattern of Svecokarelian deformation of the TIB. However, interpretation of regional aeromagnetic data suggests that the granites occur within a broad, NNE-SSW trending linear belt, pointing to deep seated tectonic control on their generation, ascent and emplacement. Thermochronology indicates that the granites were emplaced at depths between 4 and 8 km into brittle wall rocks. The 3-D shape of the Goetemar and Uthammar plutons has been investigated by 2.75D forward modelling of the residual gravity anomalies due to both granites. Both granites are associated with strong residual gravity anomalies of up to -10 mgal. Constraints on the geometry of the plutons at the surface are provided from surface geology maps and several deep boreholes located on or close to the model profiles. A further variable in the gravity modelling is introduced by either allowing the upper contact of the plutons to assume the most suitable orientation to produce the best fit between the modelled and observed gravity ('unconstrained models') or by forcing the near surface orientation of the contacts to be vertical ('constrained models'). The unconstrained model profiles for both plutons are characterized by gently outward dipping upper contacts to depths approx1 km, gently inward dipping lower contacts and a thin, centrally located root extending to depths of 5 to 10 km. However, this geometry is not supported by available boreholes, which do not penetrate the upper contact of the Goetemar pluton as predicted by the models. The constrained models are consistent with borehole data. They characterize the plutons as having vertical contacts in the upper 500 to 1,000 m, a 1,000 to 1,500 m thick mid-level body with outward dipping upper and horizontal and lower contacts, respectively, and broad roots extending to depths of approx4 km. Preliminary observations and gravity modelling results indicate that the Goetemar and Uthammar granites are discordant plutons with geometries most consistent with punched laccoliths, with some modification due to floor subsidence due to root development. Their vertical and lateral dimensions fall in the upper range for laccoliths and lower range for plutons as defined by recent data compilations. Their emplacement required elastic bending and eventual failure of roof rocks that was likely accompanied by reactivation of pre-existing fractures and shear zones and possibly the creation of new brittle fractures. Cooling and crystallization of the granites resulted in thermal resetting of the wall rocks and the establishment of a transient hydrothermal system, now recorded by fracture filling mineral assemblages

  3. Contribution to uranium geochemistry in intrusive granites

    International Nuclear Information System (INIS)

    This work aims to define the position of a certain number of French granitic deposits within the field of the geochemistry of granites in general, and of the geochemistry of uranium in particular. The regions concerned are: - 3 French Hercynian ranges, in the Vendee, in Brittany and in the Morvan, - 1 African range, probably precambrian, of the Hoggar. For each range, the petrochemical framework is first of all determined and then the degree of chemical homogeneity of the rocks is evaluated. In the petrochemical groups thus obtained the geochemical behaviour of the uranium is studied. From a point of view of the geochemistry of the granites under investigation, a comparison of the laws of distribution of the major elements in the 4 ranges shows up a convergence of average composition which was not anticipated by geological and petrographic considerations alone. The statistical and geochemical distribution laws of the total uranium as a function of the petrochemical variations are established. A study of the chemical forms of uranium in the rocks has drawn an attention to the qualitative and quantitative importance of the fraction of this uranium soluble in dilute acids. We have therefore reconsidered on the one hand, the laws of distribution of the insoluble uranium, which represents essentially the uranium fixed in crystalline structures (zircon, allanite...), and we have justified on the other hand the interest presented by the soluble uranium: this, although more complex in character, presents a geochemical unity in post magmatic phenomena which makes possible to find a genetic connection between the uraniferous deposits and the intrusive massifs. Finally we have given a plan of the geochemical cycle of uranium, in which we hope to have provided some more accurate data on the igneous phase. (author)

  4. Contribution to the study of radioactivity in younger granites in Southeastern Desert, Egypt

    Science.gov (United States)

    Kamel, A. F.

    The Egyptian granites are the most dominant rock unit of the basement complex in Eastern Desert. Several geological investigations and classifications were carried out on these granites. They were classified according to relative age, dominant colour, type locality and their apparent relation to orogeny. Most of the discovered radioactive occurrence are encountered in the younger granites which are generally enriched in uranium than other rock types. The present work deals with the distribution of radioactivity in younger granites represented in the Southeastern Desert of Egypt and the identification of these granites on aerial photographs and photomosaics in a trial to differentiate between granites with normal to moderate radioactivity and those having higher and anomalous radioactivity. The younger granites have a wide range of radioactivity which is from 400 to 1000 count per second in the granites with normal to moderate radioactivity while it reaches 2000 count per second in the granites with abnormal radioactivity as given in the radiometric map constructed by Lockwood in 1968. Some outcrops of the second type are found with disseminated uranium mineralizations, and in certain localities field measurement of their radioactivity gave values of 10 000 count per second, and even more. Photogeologically, the younger granites are characterized by lighter tone, coarser surface texture, angular to rectangular drainage pattern and the sharp contact against the other types of rocks. Granites with higher to anomalous radioactivity are highly fractured as compared with the other rocks of younger granites.

  5. Characteristics and significance of uranium bearing pan african younger granite in the eastern desert, Egypt

    International Nuclear Information System (INIS)

    Surficial uranium mineralization was discovered in four pan african younger granite plutons in the eastern desert of egypt. The present study revealed great similarity between these plutons both in petrography and geochemistry. They are two-feldspar, two-mica peraluminous granites which have been formed by melting of crustal materials and emplaced during the late stage stage of a late proterozoic orogenic cycle. Radiometric and geochemical investigations indicate that these granites are fertile with respect to U and form a potential target for primary uranium deposits. Four models are suggested to explain the source and mechanism of the surficial uranium mineralization in these granites. The most applicable model is the oxidation of U+4 found in minute disseminated uraninite grains and its subsequent mobilization. This is supported by petrographic and autoradiographic studies. The bearings of the present study on further exploration for uranium deposits in granites of the arabian- Nubian shield in general are discussed

  6. Uranium-bearing siliceous veins in younger granites, Eastern Desert, Egypt

    International Nuclear Information System (INIS)

    The post-tectonic younger granites of Egypt represent the magmatic activity marking the end of the cratonization process of the Pan-African Orogeny. Several of these plutons are hosts of rare metal mineralization in the Eastern Desert of Egypt. Two of them, namely El-Erediya and El-Missikat plutons, are hosts of siliceous vein-type uranium mineralization. In both occurrences, the mineralization is structurally controlled by faults and their feather joints which are associated with NE to ENE shear zones. Widespread silicification, and to a lesser extent kaolinization and sericitization, as well as other alterations accompany the uranium mineralization. Uranium is concentrated in the centre of the mineralized faults and fractures together with jasper (in El-Erediya) or black silica and to a lesser extent jasper (in El-Missikat). Pitchblende is the primary mineral which suffered intensive oxidation and probably leaching relics protected by silica. This resulted in a spotty distribution of uranium and radioactivity in the oxidation zone. Present data suggest an origin by hydrothermal fluids derived, most probably, from the younger granite magma. Uranium was derived from the magma itself, or from another deep source. Contributions from the granitic plutons by leaching through circulation of meteoric waters cannot be ruled out at the present state of knowledge. (author)

  7. Petrogenesis And Geochronology Of The Granitic Intrusions Of Gabal Kulyiet And Seiga, South Eastern Desert, Egypt

    OpenAIRE

    Meneisy, M. Y. [???? ???? ?????

    1986-01-01

    In the South Eastern Desert of Egypt tonalite. granodiorite and granite intruded intermediate to acidic metavolcanics and volcanogenic metasedimentary rocks of Precambrian age. The geological features of these granitic masses were investigated and a geological map (scale 1 : 40 000) was prepared. They have been classified into two groups: tonalite and granodiorite (syn to late-tectonic), and biotite and Muscovite granites (younger granitoids). The two groups appear to be genetically related o...

  8. Genesis of Uranium in the younger granites of gabal abu hawis area, central eastern desert of Egypt

    International Nuclear Information System (INIS)

    The younger granites cropping out in gabal abu hawis area are considered as uraniferous (fertile) granites (the fertile is mainly is mainly attributed to presence of radioactive zircon). Abu hawis granitic pluton is dissected by joints faults of different trends forming two mineralized shear zones in the northern peripheries and southern border. The younger granites hosting uranium mineralizations along the two mineralized shear zones. The uranium minerals include uranophane and carnotite. The altered granites have much lower Th/U ratios (0.03-0.10) than those of the fresh granites (1.69-2.05), indicating strong mobilization of uranium in this pluton by super-heated solutions that resulted from supergence meteoric water as well as U-addition by hypogene fluids. These solutions could pass through the structural network of fractures, joints and fault planes and have leached some of labile uranium from the surrounding rocks and/or the younger granites themselves. Then, changing in the physicochemical conditions of these solutions caused uranium precipitation as uranium minerals filling the cracks in the rock and/or adsorbed on the surface of clay minerals and iron oxides in the two shear zones

  9. Oxygen isotope geochemistry of the Granite Harbour Intrusives, Wilson Terrane, Northern Victoria Land, Antarctica

    International Nuclear Information System (INIS)

    The oxygen and strontium isotope compositions of the Cambro-Ordovician granitoids cropping out in the Wilson Terrane (Granite Harbour Intrusives-GHI) constrain the petrological evolution of the magmatism in Antarctica, related to the Ross Orogeny. The measured ?18OWR values of three intrusives define three different compositional groups: the metaluminous rocks (MAG), with ?18OWR ranging from 6.9 (olivine gabbro) to 11.4 %o (monzogranite); the unaltered peraluminous granites (PAG), having ?18OWR values ranging from 10.6 to 13.2 %o, and the foliated peraluminous leucogranites (SKG), characterized by ?18OWR values above 14 %o. The analysis of equilibrium mineral assemblages indicates that the high ?18OWR values are magmatic and unaffected by low-temperature processes. A few peraluminous granites sampled in the vicinity of Cenozoic intrusions show anomalously low ?18OWR, due to meteoric-hydrothermal alteration. The isotopic data indicate that the coeval and spatially related metaluminous mafic and felsic intrusives forming the GHI were not comagmatic: the mafic and intermediate rocks were likely derived from lower crustal contamination of a pristine basaltic magma; their ?18OWR values were also increased during emplacement, due to the interaction with the adjacent 18O-rich hydrous felsic magmas (mixing)rich hydrous felsic magmas (mixing). Oxygen isotope data indicate that the crustal sources producing the granite harbor intrusives were not homogeneous: the felsic metaluminous intrusives were produced by partial melting of fertile rock with possible igneous origin, whereas partial melting of a metapelitic source rock is claimed for the genesis of the peraluminous granites. (author)

  10. Three Paleoproterozoic A-type granite intrusions and associated dykes from Kainuu, East Finland

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    Hannu Huhma

    2010-12-01

    Full Text Available Mafic and felsic intrusive rocks aged 2.5–2.4 Ga have been observed over a large area in eastern and northern Finland, as well as in adjacent northwestern Russia. We describe three granite intrusions and associated dykes from Kainuu, Finland, that belong to this bimodal magmatic event. All these three granites show clear A2-type chemical affinities with high Y/Nb, HREE, Fe/Mg, Ga and Nb. Two of the intrusions, Rasinkylä and Pussisvaara, were dated at 2425±3 and 2427±3 Ma, respectively, using thermal ionisation mass spectrometry utilizing the chemical abrasion method (CA-TIMS. CA-TIMS ages are supported by single-grain age determinations obtained by using Laser Ablation Multicollector Inductively Coupled Plasma Mass Spectrometer (LA-MC-ICPMS. New data on the previously described Rasimäki granite from southern Kainuu is presented, including an age of 2389±5 Ma obtained with LA-MC-ICPMS. The variable magnetite content of the granites is proposed to reflect the differences in the oxidation state of the source, which in our interpretation is the local Archean lower crust. Partial melting and the emplacement of the granites occurred in an extensional environment. Heat for the partial melting was provided by mafic magmas under and intraplating the extended crust.

  11. Discriminations of Younger Granitic Masses at Gabal Qattar Area, North Eastern Desert, Egypt, Using Remote Sensing Techniques

    International Nuclear Information System (INIS)

    Gabal Qattar area is located in the north Eastern Desert of Egypt between Latitudes 26 degree 52 and 27 degree 08 N, and Longitudes 33 degree 13 and 33 degree 25 E. The exposed rock units, there, from the oldest to the youngest, are meta volcanics; granodiorites- diorite complex; Hammamat sediments and younger granites. Most of the area is densely traversed by felsic and mafic dykes. The Qattarian younger granites are divided into seven granitic areas according to their spectral characters to facilitate the studying and delineating physical characteristic differences between these areas as well as to throw a light about the best conditions of exploration for radioactive mineralizations. This study is based on brightness Digital Number values (DNs) of the granitic areas, predominant trends and densities of the structural lineaments, shape and type of weathering products. Three areas of these seven younger granite areas form Gabal (G.) Qattar, and designated Gr 1, Gr 3 and Gr 4, where the other granite areas which form the G. Urn Dissi (Gr 2), G. Thelma (Gr 5), G. Abu Samyuk (Gr 6) and G. Ayn AI Ruwayshed (Gr 7). Photo geologically, these seven granite areas show some differences in shape, texture, predominant trends and densities of structural lineaments and ability of weathering. This study shows that the seven granite areas could be gathered into three main groups according to their DNs values of Landsat ETM+ spectral bands especially of band 5, where these three maispecially of band 5, where these three main groups representing different, and mainly coincide with the three granite phases previously delineated according to chronological field relation, petrographic and geochemical studies. The Gr 1 area contains all uranium occurrences from locations I to V. This area is characterized by semi circular shape of NW trend, massive appearance with high relief peaks, and high fracture density, where the N 55 degree E, N 5 degree E, N 45 degree E and N 45 degree W are the predominant trends. Some of the N 55 degree E fractures form shear zone along the contact with Hammamat sediments. This granitic area displays taffoni weathering with highest clay minerals content in its weathered surfaces. It shows the highest brightness value (DN), especially in band 5 reaching about 152, due to the highest felsic minerals and the lowest ferro magnesian minerals contents relative to the other granite areas. Also, the high fractures density of the Gr 1 area acted as good channels for the hydrothermal ascending fluids and the percolating meteoric water, that leached uranium mineralization and redeposited it in the shear zones especially at sites of intersection of the main fractures. These characteristic features of the Gr 1 area may be responsible for the presence of uranium mineralizations

  12. Age of Pedra Branca granite (Goias) and possible geotectonic implications

    International Nuclear Information System (INIS)

    Rb-Sr geochronologic dating of granites from the Pedra Branca Granite Massif (Nova Roma, Goias) shown an age of 1405 ± 21My. and a questionable initial Sr87/Sr86 ratio of 0,7004 ± 0,006. Rhyolite from the base of the Arai Group is probably of the same age as the granitic intrusion. The 475 ± 19 My. age for the granitic intrusion is evidence of the Brasiliano Cycle imprint in Pedra Branca region. The age attributed to the Pedra Branca Granite is lower than known ages of the Goias tin granites giving rise to new geotectonic interpretations. It is possible that the Pedra Branca Granite represents a low-level intrusion emplaced at the beginning of structuration and deposition of the Arai basin. It may be correlated with granitic intrusions related to a rift stage above mantle hot spots, like the Nigerian tin younger granites. (author)

  13. Granite intrusion in a metamorphic core complex: The example of the Mykonos laccolith (Cyclades, Greece)

    OpenAIRE

    Denèle, Yoann; Lecomte, Emmanuel; Jolivet, Laurent; Lacombe, Olivier; Labrousse, Loïc; Huet, Benjamin; Le Pourhiet, Laetitia

    2011-01-01

    The Aegean domain is a well-suited place to study the formation of metamorphic core complex (MCC) and to investigate the role of syn-tectonic granites on their development. In the northern Cyclades, the Mykonos-Delos-Rhenia MCC is characterised by the intrusion of a kilometer-scale Late Miocene pluton of I-type granitoids within a migmatitic gneiss dome. New combined AMS (Anisotropy of Magnetic Susceptibility) and microstructural studies on the Mykonos granitoids together with recently publis...

  14. Electron microprobe monazite geochronology of granitic intrusions from the Montes de Toledo batholith (central Spain)

    OpenAIRE

    Orejana Garci?a, David; Merino Marti?nez, Enrique; Villaseca Gonza?lez, Carlos; Pe?rez-soba Aguilar, Cecilia; Cuesta, Andre?s

    2012-01-01

    U–Th–Pb monazite dating by electron microprobe has been applied to three peraluminous granitic intrusions of the western Montes de Toledo batholith (MTB). Back scattered electron images of monazite crystals reveal a variety of internal textures: patchy zoning, overgrowths around older cores and unzoned crystals. On the basis of their zoning pattern and chemical composition, two monazite domains can be distinguished: (1) corroded cores and crystals with patchy zoning, exhibiting r...

  15. Geochemical Characteristics and Chemical Electron Microprobe U-Pb-Th Dating of Pitchblende Mineralization from Gabal Gattar Younger Granite, North Eastern Desert, Egypt

    OpenAIRE

    Hassan A. A. Shahin

    2014-01-01

    Pitchblende mineralization was studied in the younger granite samples collected from Gabal Gattar, north Eastern Desert, Egypt using electron scanning microscope (ESM) and electron probe microanalyses (EPMA). This study revealed that this pitchblende contains significant Zr content reaching up to (66.80% ZrO2), which suggests that volcanic rocks were probably the source of such a deposit. High level emplaced high-K Calc-alkaline plutons as Qattar granite may have bee...

  16. Pegmatoid schlieren with tourmaline in granitoids of eastern russia as an attribute of intrusive series completed by ore-bearing Li-F granites

    Science.gov (United States)

    Alekseev, V. I.; Marin, Yu. B.

    2014-12-01

    Tourmaline schlieren in pegmatoids and host granites are widespread in Cretaceous granitoid plutons occurring in tin districts of eastern Russia. These schlieren were formed under the action of fluoricboron fluids, which are considered to be forerunners of rare-metal granite magmatism. The tourmaline schlieren in adamellites, biotite, and two-mica granites are reliable attributes of intrusive series completed by emplacement of ore-bearing Li-F granites.

  17. Natural radioactivity of basement younger granite rocks from the Eastern Desert

    International Nuclear Information System (INIS)

    The present work deals with a study of natural radioactivity of various samples of granite rocks from the Umm Gidri area located in North Eastern Desert. In this area, about 300 km apart from El-Minia, some geological investigations were carried out. Several samples of the basement rocks (of the Precambrian Age) 5 m subsurface were obtained from different locations. Suitable samples were prepared for natural gamma ray measurements using a 5 x 5 in. NaI(Tl) scintillation spectrometer. Qualitative analysis of natural gamma radiations from the present samples have revealed the presence of the radioisotopes: 40K, 214Bi, 208Tl and 228Ac in meaningful concentrations. These results are thought to correlate with the findings of a recent trace element geological assay done at the same area, and it would be of help in monitoring and assessing the national background radiation levels. (Author)

  18. Assessment of the radiological consequences of human intrusion into repositories located in granite

    International Nuclear Information System (INIS)

    The method used in France to assess the radiological impact of waste repositories in granite consists in making a deterministic analysis of the normal evolution scenario (base case scenario) and a limited number of altered evolution scenarios which, for each series of plausible scenarios, are those with the greatest potential impact. In view of the importance of the human intrusion scanario, and following a request from the working party on site selection criteria chaired by Professor Goguel, a study has been made of this scenario under the CEC PAGIS project. A description of the Auriat site drawn up under the PAGIS project was used as a basis for analyzing the radiological consequences of an intrusion (after periods ranging from 1 000 to 100 000 years subsequent to closure of the repository) assumed to result in the creation of a cavern equivalent to a cube measuring 100 m along each side. Three different scenarios were considered (mine worker, stock rearing, gardening). Except for the mine worker scenario, which produced exposure rates of up to 10 millisieverts/year, a figure that is in fact comparable to the dose to which workers in conventional mines are exposed, the calculated dose equivalents were relatively low

  19. Spatial association of Neoproterozoic continental arc I-type and post-collision A-type granitoids in the Arabian-Nubian Shield: The Wadi Al-Baroud Older and Younger Granites, North Eastern Desert, Egypt

    Science.gov (United States)

    El-Bialy, Mohammed Zaky; Omar, Mohamed M.

    2015-03-01

    The Neoproterozoic basement of Wadi Al-Baroud area located at the northern Eastern Desert (ED) of Egypt, at the northernmost segment of the Arabian-Nubian Shield (ANS), is comprised of two different granite suites. A large batholith ascribed to the Older Granite suite, extends across the boundary between the northern and central ED, and is intruded by two isolated plutons of the Younger Granite suite. The Older Granite suite includes gray-colored, massive to gneissose, granodiorites to tonalites typically containing microgranular mafic enclaves. These are calc-alkaline, magensian, metaluminous I-type granitoids, with high Sr contents, and depleted in Rb, Nb, Y and REE. The Younger Granite suite plutons are pink to red, biotite and two-mica monzogranites. These are peraluminous A-type granites exhibiting a high-K calc-alkaline nature, and varying between ferroan and magnesian type granites. The A-type granites of the Younger Granite suite are enriched in Ga, Y, HFSE and REE elements, and depleted in the LILE elements Ba, Sr and Rb and transition metals Cr, Ni, Co, Sc and V. Magmatic saturation temperatures indicate early crystallization of apatite at high temperature in the metaluminous I-type Older Granite suite, while in the peraluminous A-type Younger Granites its crystallization occurs later after separation of zircon and monazite. The plutons of the Younger Granite suite were generated during the post-collisional stage of the northern ANS, following collision between the juvenile ANS crust and the pre-Neoproterozoic continental blocks of west Gondwana. The emplacement of the Older Granite suite took place earlier, within a normally mature continental arc prior to the collision. These pre-collision granitoids evolved through assimilation-fractional crystallization processes from mantle-derived parental magmas, which have interacted with crustal materials during ascent and storage. The post-collisional Younger Granite suite seems to have been derived by high degree, partial melting of metasedimentary sources, particularly psammitic and pelitic metasediments.

  20. U-Pb conventional dating compared to SHRIMP of the Santa Barbara Granite Massif, Younger Granites Suite of Rondonia, Brazil; Datacoes U-Pb convencional versus SHRIMP do macico estanifero Santa Barbara, Suite Granitos Ultimos de Rondonia, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Sparrenberger, Irena [Sao Paulo Univ., SP (Brazil). Inst. de Geociencias. Programa de Pos-graduacao em Recursos Minerais e Hidrogeologia; Bettencourt, Jorge Silva [Sao Paulo Univ., SP (Brazil). Inst. de Geociencias. Dept. de Mineralogia e Geotectonica; Tosdal, Richard M. [Univ. of British Columbia, Vancouver (Canada). Dept. of Earth and Ocean Sciences; Wooden, Joseph L. [Stanford Univ. (United States). Ion Probe Lab.

    2002-12-15

    The Santa Barbara Granite Massif is part of the Younger Granites of Rondonia (998 - 974 Ma) and is included in the Rondonia Tin Province (SW Amazonian Craton). It comprises three highly fractionated metaluminous to peraluminous within-plate A-type granite units emplaced in older medium-grade metamorphic rocks. Sn-mineralization is closely associated with the late-stage unit. U-Pb monazite conventional dating of the early-stage Serra do Cicero facies and late-stage Serra Azul facies yielded ages of 993 +- 5 Ma and 989 +- 13 Ma, respectively. Conventional multigrain U-Pb isotope analyses of zircon demonstrate isotopic disturbance (discordance) and the preservation of inherited older zircons of several different ages and thus yielded a 207 Pb/206 Pb weighted-mean age of 978 +- 13 Ma. The textural complexity of the zircon crystals of the Santa Barbara facies association, the variable concentrations of U, Th and Pb, as well as the mixed inheritance of zircon populations are major obstacles to using conventional multigrain U-Pb isotopic analyses. Sm-Nd model ages and epsilon{sub Nd}(T) values reveal anomalous isotopic data, attesting to the complex isotopic behaviour within these highly fractionated granites. Thus, SHRIMP U-Pb zircon and conventional U-Pb monazite dating methods are the most appropriate to constrain the crystallization age of the Sn-bearing granite systems in the Rondonia Tin Province. (author)

  1. GRANNY, a data bank of chemical analyses of Laramide and younger high-silica rhyolites and granites from Colorado and north-central New Mexico

    Science.gov (United States)

    Steigerwald, Celia H.; Mutschler, Felix E.; Ludington, Steve

    1983-01-01

    GRANNY is a data bank containing information on 507 chemically analyzed Laramide or younger high-silica rhyolites and granites from Colorado and north-central New Mexico. The data were compiled from both published and unpublished sources. The data bank is designed to aid in the recognition of igneous rocks with a high exploration potential for the discovery of molybdenum (and other lithophile element) deposits. Information on source reference, geographic location, age, mineralogic and petrologic characteristics, major constituent analyses, and trace element analyses for each sample are given. The data bank is available in two formats: 1) paper- or microfiche-hardcopy, and 2) fixed format computer readable magnetic tape.

  2. Geochronology, geochemistry, and isotope compositions of Piaochi S-type granitic intrusion in the Qinling orogen, central China: Petrogenesis and tectonic significance

    Science.gov (United States)

    Qin, Zheng-wei; Wu, Yuan-Bao; Wang, Hao; Gao, Shan; Zhu, Liu-Qin; Zhou, Lian; Yang, Sai-Hong

    2014-08-01

    S-type peraluminous granite can crop out in various tectonic settings. The Paleozoic Piaochi granitic intrusion is a large S-type peraluminous intrusion located in the North Qinling orogen, and has important implication for its tectonic evolution. Though intensively studied, the age and tectonic setting of this intrusion are still controversial. In this study, we carried out an integrated study of zircon U-Pb age, major and trace elements, and Sr-Nd-Hf-O isotope compositions for the Piaochi intrusion, with aims to constrain its petrogenesis and tectonic significance. SIMS and LA-ICPMS U-Pb zircon data obtained from magmatic zircons indicate that the Piaochi intrusion was emplaced at 473 ± 4 Ma, and contained ca. 490 Ma inherited zircons. The granite samples from the Piaochi intrusion show typical S-type characteristics, such as the relatively moderate aluminum saturation index (1.00-1.08), low zirconium saturation temperatures, occurrences of muscovite, and high zircon ?18O values (8.70 to 9.54‰). The relatively low Sm/Nd (0.13-0.20) and FeOT/MgO ratios (2.21-3.9) suggest that the granites are unfractionated. The geochemical compositions reveal that they were derived from partial melting of a clay-poor, but plagioclase- and biotite-rich psammitic source, similar to metasedimentary rocks outcropping in the North Qinling unit. Moreover, the Piaochi granites are moderately depleted in Eu and heavy rare earth elements, and have relatively high (La/Yb)N values (22.8-56.8), implying a high-pressure, plagioclase-poor and garnet-rich residual assemblage. The Piaochi granites have high and variable initial 87Sr/86Sr ratios (0.72167-0.72511) and low ?Nd(t) (from - 10.23 to - 8.71) values with two-stage Nd model ages (TDM2) of 1.91-2.03 Ga, which are comparable with those of supracrustal materials in the North Qinling unit. In addition, our results show that the ca. 470 Ma magmatic zircons display a narrow ?Hf(t) array within those of the inherited cores. These imply that the Piaochi granites inherited their isotopic characteristics wholly from their sources, and the Hf isotopes might have been differently homogenized during the partial melting. Our new zircon U-Pb ages indicate that the Piaochi granites were emplaced after the climax of the UHP metamorphism, coeval with later retrograde metamorphism during exhumation. Therefore, we suggest that the formation of the early Paleozoic Piaochi intrusion was triggered by the exhumation of the UHP rocks.

  3. Gravimetric modeling of the Parguaza granitic intrusion, Guyana Precambrian Shield, southwestern Venezuela using geochronological constraints

    Directory of Open Access Journals (Sweden)

    Oscar Mirón-Valdespino

    2004-12-01

    Full Text Available A combined gravimetric and geochronological interpretation of the Parguaza intrusion in the Guayana shield, southwestern Venezuela, indicates that there is a pattern of inverse cooling within this pluton. Based on a positive correlation between Rb/Sr whole rock apparent ages and residual Bouguer anomaly, density contrasts over the Parguaza intrusion are linked to temperature and crystallization of mineral phases. This hypothesis is supported by density measurements on hand samples and by independent geochemical evidence. A simple 2D gravity model is constrained by surface geology, Rb/Sr apparent ages (whole rock and residual Bouguer anomalies. Gravimetric modeling implies a model of horsts and grabens that accounts for inverse zoning of the intrusion as a result of geological and age contrasts across the faults.

  4. The application of radioelement studies in solving petrological problems of the precambrian intrusive Homme granite in the Flekkefjord area, South Norway

    International Nuclear Information System (INIS)

    A Th- and U-enriched granite has been found within a sequence of high-grade metamorphic gneisses and migmatites in the Flekkefjord area bordering the S Rogaland anorthosite province in SW Norway, where the country rocks and the other intrusions all have very low contents of these elements. The major-element distribution within the Homme granite suggests a certain magmatic differentiation, although a K- and Si-rich zone in connection with the discordant northern contact is supposed to be due to assimilation of felsic country rocks. This model was tested by studying the radioelements which exhibit the lowest values exactly in the northern K- and Si-rich zone, thus supporting the model of assimilation, while the alkali enrichment in the southermost part is connected with high contents of radioelements, thus suggesting a rest magmatic stage. (Auth.)

  5. Felsic Intrusion in a Strike-slip Dilational Overstepping Linkage in the Upper Crust: An Example of Palgongsan Granite in SE Korea

    Science.gov (United States)

    Gwon, S.; Jang, Y.; Kim, Y. S.

    2014-12-01

    The Palgongsan Granite which intruded into the Cretaceous Gyengsang Basin in SE Korea is elongated in NW-SE direction (ca. 2.4 aspect ratio of long axis to short in exposure) and is generally thought as being emplaced along the WNW-ESE trending Palgongsan Fault which is the boundary between the Uiseong sub-basin (north) and Miryang sub-basin (south) within the basin. It is widely believed that emplacement of the pluton along the sub-basin boundary removed all evidence associated with the faulting. Recent studies of gravity and aeromagnetic anomalies in the vicinity of the granite imply that the emplacement of this pluton was controlled by the geometry of WNW-ESE trending right-lateral overstepping lineaments. It gives us an opportunity to examine the controlling factors for emplacement such as the internal structural characteristics of the pluton, thermal cooling history, residual magmatic fluid pressure, and external regional stress regime. Within the granite, pegmatitic dykes and hydrothermal deposits related to the late stages of intrusion are frequently observed and penetrative joints and faults are also well developed. The study of orientation, distribution, relative cross-cutting relationships and kinematics based on the indicators of each structural element coupled with geochronological and geophysical data provides information of the prevailing stress regime at the time of dyke intrusions and the controlling structures, such as strike-slip overstepping and dilational linkage. The results of 3-D mohr-circle analysis for NW-SE trending dykes show they intruded under vertical ?1 and NE-SW horizontal ?3 in low differential stress and relatively high residual pressure of magmatic fluid. This coincided with regional NW-SE horizontal ?1 and NE-SW horizontal ?3 direction based on other structural analysis. Although these results imply the possibility that the pluton was emplaced in a dilational overstep along a WNW-ESE reactivated dextral strike-slip fault, felsic intrusions in the upper crust are not only controlled by pre-existing structures but are also controlled by other factors such as magmatic flow behavior. Therefore further studies such as magnetic anisotropy suspension and seismic exploration are required to fully understand the mode of emplacement of the Palgongsan Granite.

  6. Determination of concentrations and isotopic ratio of uranium in groundwaters drawn from two deep wells drilled in granitic rocks belonging to Itu intrusive suite

    International Nuclear Information System (INIS)

    This paper presents the first results obtained in the determination of dissolved uranium concentrations and (234U/238U) activity ratios of groundwaters drawn from two deep wells drilled in granitic rocks belonging to Itu Intrusive Suite, which is located at eastern Sao Paulo State. One of the wells, whose groundwaters have been analyzed, is located in Salto Town, while the other one is located in Itu Town. The groundwater sampling is monthly and begun on September, 2004, in order to investigate possible sazonal variations. The alpha spectrometry technique, associated with isotopic dilution method, has been used for these determinations. The data obtained up to now show that the groundwaters from Salto present uranium concentrations significantly lower ((0.098 ± 0.007) - (0.17 ± 0.01) ng/g) than those from Itu ((0.22 ± 0.02) - (0.31 ± 0.02) ng/g). The 234U and 238U isotopes of the investigated groundwaters from both wells are in radioactive disequilibrium, with (234U/238U) activity ratios systematically higher than unity. Although the groundwaters from Salto well are characterized by low 234U and 238U specific activities they present higher (234U/238U) activity ratios than those from Itu. The observed differences on the behavior of uranium concentrations and (234U/238U) activity ratios in the groundwaters from the two wells are very prdwaters from the two wells are very probably due to the large variety of granitic rocks from Itu Intrusive Suite, which are characterized by distinct uranium abundances. (author)

  7. Structure and timing of Neoarchean gold mineralization in the Southern Cross district (Yilgarn Craton, Western Australia) suggest leading role of late Low-Ca I-type granite intrusions

    Science.gov (United States)

    Doublier, Michael P.; Thébaud, Nicolas; Wingate, Michael T. D.; Romano, Sandra S.; Kirkland, Christopher L.; Gessner, Klaus; Mole, David R.; Evans, Noreen

    2014-10-01

    The formation of structurally controlled lode-gold deposits is a controversial subject with both magmatic and metamorphic fluids considered a feasible source for gold. Here we present a study from the Southern Cross district (Yilgarn Craton, Western Australia), where structurally controlled Neoarchean gold deposits are hosted in amphibolite facies greenstones. We combine geochronological data with structural analysis to constrain the timing and structural control of ore deposition. We show that gold mineralization took place between c. 2638 and 2630 Ma, contemporaneous with the onset of voluminous intrusions of Low-Ca, I-type granites, which are ubiquitous in Southern Cross and elsewhere in the Yilgarn Craton. We argue that the timing of the intrusions, their spatial association with gold deposits, their chemical composition, and isotopic signature are consistent with Low-Ca granites being a major fluid source for mineralization. We propose that the fluid release by cooling plutons was facilitated by transport along active amphibolite facies shear zones. As gold mineralization was synchronous with Low-Ca magmatism across large areas of the Yilgarn Craton, our model may be applicable to orogenic gold deposits in other parts of the Yilgarn Craton as well as other Archean granite-greenstone terrains with a 'late granite bloom'.

  8. Extreme U-Th disequilibrium in rift-related basalts, rhyolites and granophyric granite and the timescale of rhyolite generation, intrusion and crystallization at Alid volcanic center, Eritrea

    Science.gov (United States)

    Lowenstern, J. B.; Charlier, B.L.A.; Clynne, M.A.; Wooden, J.L.

    2006-01-01

    Rhyolite pumices and co-erupted granophyric (granite) xenoliths yield evidence for rapid magma generation and crystallization prior to their eruption at 15.2 ?? 2.9 ka at the Alid volcanic center in the Danikil Depression, Eritrea. Whole-rock U and Th isotopic analyses show 230 Th excesses up to 50% in basalts <10 000 years old from the surrounding Oss lava fields. The 15 ka rhyolites also have 30-40% 230Th excesses. Similarity in U-Th disequilibrium, and in Sr, Nd, and Pb isotopic values, implies that the rhyolites are mostly differentiated from the local basaltic magma. Given the (230 Th/232Th) ratio of the young basalts, and presumably the underlying mantle, the (230Th/232Th) ratio of the rhyolites upon eruption could be generated by in situ decay in about 50 000 years. Limited (???5%) assimilation of old crust would hasten the lowering of (230Th/232Th) and allow the process to take place in as little as 30 000 years. Final crystallization of the Alid granophyre occurred rapidly and at shallow depths at ???20-25 ka, as confirmed by analyses of mineral separates and ion microprobe data on individual zircons. Evidently, 30 000-50 000 years were required for extraction of basalt from its mantle source region, subsequent crystallization and melt extraction to form silicic magmas, and final crystallization of the shallow intrusion. The granophyre was then ejected during eruption of the comagmatic rhyolites. ?? 2006 Oxford University Press.

  9. The petrogenesis of a wolframite-bearing greisen in the Vykmanov granite stock, Western Krušné hory pluton (Czech Republic)

    OpenAIRE

    Štemprok M; Pivec E; Langrová A

    2005-01-01

    A wolframite-bearing greisen at Vykmanov, near Ostrov (Czech Republic) occurs at the contact of a small granite stock belonging to the Late Variscan Younger Intrusive Complex (YIC) of the Western Krušné hory/Erzgebirge pluton. The stock emerges as an outcrop of 0.8 × 0.3 km size from a hidden granite body in the eastern continuation of the Nejdek-Eibenstock granite massif. The lens-like greisen body consists mainly of quartz, topaz, protolithionite, and muscovite; it also contains wolframi...

  10. Genetic relationship between L granite body and 3701 uranium deposit

    International Nuclear Information System (INIS)

    The ore deposit occurs in carbonate rocks situated in the exocontact zone (0 - 120 m) with the L granite body. The mineralization is hosted by argillaceous limestone of the middle Devonian Yingtang Formation. The ore bodies are in lenticular or stratifed form. The ores are fine vein-type and disseminated type. Four stages of mineralization in the deposit are recognized. Industrial mineral is pitchblende which occurs as micro-impregnation and micro-vein in the calcite, and fills or replaces its associated minerals. Gangue minerals are chiefly calcite, pyrite, galena, sphalerite, chalcopyrite and tennantite etc. The host rocks of the ore-veins show weak hydrothermal alterations with plane and linear distribution. The L granite body with an area of 238 km2 is a single-stage intrusive batholith which mainly consists of coarse-medium grained biotite granites. Because the urnium mineralization age (65.0 - 30.7 Ma) is much younger than that of the L granite (318 -202 Ma), it may be considered that the deposit is genetically not related to activity of the L granitic magma. However, the granitic rocks may play an important role in the formation of the 3701 uranium deposit in following hands: providing a large number of uranium and lead; providing minor amounts of surfur, carbon and trace elements; forming impermeable basement to promote the accumulation of uranium-bearing solution; providing an additional heat source for heating ore-bearing solution and its convectiting ore-bearing solution and its convective circulation

  11. Timing, petrogenesis and tectonic setting of the Late Paleozoic gabbro-granodiorite-granite intrusions in the Shalazhashan of northern Alxa: Constraints on the southernmost boundary of the Central Asian Orogenic Belt

    Science.gov (United States)

    Shi, Xingjun; Wang, Tao; Zhang, Lei; Castro, Antonio; Xiao, XuChang; Tong, Ying; Zhang, Jianjun; Guo, Lei; Yang, Qidi

    2014-11-01

    The Late Paleozoic tectonic setting and location of the southernmost boundary of the Central Asian Orogenic Belt (CAOB) with respect to the Alxa Block or Alxa-North China Craton (ANCC) are debated. This paper presents new geochronological, petrological, geochemical and zircon Hf isotopic data of the Late Paleozoic intrusions from the Shalazhashan in northern Alxa and discusses the tectonic setting and boundary between the CAOB and ANCC. Using zircon U-Pb dating, intrusions can be broadly grouped as Late Carboniferous granodiorites (~ 301 Ma), Middle Permian gabbros (~ 264 Ma) and granites (~ 266 Ma) and Late Permian granodiorites, monzogranites and quartz monzodiorites (254-250 Ma). The Late Carboniferous granodiorites are slightly peraluminous and calcic. The remarkably high zircon Hf isotopes (?Hf(t) = + 6-+ 10) and characteristics of high silica adakites suggest that these granodiorites were mainly derived from "hot" basaltic slab-melts of the subducted oceanic crust. The Middle Permian gabbros exhibited typical cumulate textures and were derived from the partial melting of depleted mantle. The Middle Permian granites are slightly peraluminous with high-K calc-alkaline and low ?Hf(t) values from - 0.9 to + 2.9. These granites were most likely derived from juvenile materials mixed with old crustal materials. The Late Permian granodiorites, monzogranites and quartz monzodiorites are characterized as metaluminous to slightly peraluminous, with variable Peacock alkali-lime index values from calc-alkalic to alkali-calcic. These rocks were mainly derived from juvenile crustal materials, as evidenced by their high ?Hf(t) values (+ 3.3 to + 8.9). The juvenile sources of the above intrusions in the Shalazhashan are similar to those of the granitoids from the CAOB but distinct from the granitoids within the Alxa Block. These findings suggest that the Shalazhashan Zone belongs to the CAOB rather than the Alxa Block and that its boundary with the Alxa block can be regarded as the southernmost boundary of the CAOB. The recognition of Late Carboniferous typical adakite magmatism in the region provides evidence for the subduction of the oceanic crust of the CAOB. The Middle-Late Permian magmatisms (266-250 Ma) display a bimodal association with high-K calc-alkaline features and are interpreted as forming in a post-collision setting. These studies, by interaction of regional geology, provide new constraints on the tectonic evolution of the southern CAOB during the Late Paleozoic and the location of the southernmost margin of the CAOB.

  12. Neoproterozoic granitic activities in the Xingdi plutons at the Kuluketage block, NW China: Evidence from zircon U-Pb dating, geochemical and Sr-Nd-Hf isotopic analyses

    Science.gov (United States)

    Cao, Xiaofeng; Lü, Xinbiao; Yuan, Qian; Wang, Xiangdong; Liu, Hong; Shen, Wen

    2014-12-01

    Neoproterozoic igneous rocks are widely distributed in the Kuluketage block along the northern margin of the Tarim Craton. However, the published literature mainly focuses on the ca. 800 Ma adakitic granitoids in the area, with the granites that intrude the 735-760 Ma mafic-ultramafic rocks poorly studied. Here we report the ages, petrography and geochemistry of two granites in the Xingdi mafic-ultramafic rocks, in order to construct a new view of the non-adakitic younger granites. LA-ICP-MS zircon U-Pb dating provided weighted mean 206Pb/238U ages of 743.0 ± 2.5 Ma for the No.I granite (G1) and 739.0 ± 3.5 Ma for the No.II granite (G2). A clear core-rim texture of similar age and a high zircon saturation temperature of ca. 849 ± 14 °C were observed for the No.I granite; in contrast, G2 has no apparent core-rim texture but rather inherited older zircons and a lower zircon saturation temperature of ca. 763 ± 17 °C. Geochemical analysis revealed that G1 is an alkaline A-type granite and G2 is a high-K calc-alkaline I-type granite. Both granites share similar geochemical characteristics of arc-related magmatic rocks and enriched Sr-Nd-Hf isotopes, likely due to their enriched sources or mixing with enriched magma. Whereas G1 and its host mafic rocks form typical bimodal intrusions of the same age and similar Sr-Nd-Hf isotope compositions, G2 is younger than its host mafic rocks and its Sr-Nd-Hf isotope composition indicates a lower crust origin. Although they exhibit arc-related geochemical features, the two granites likely formed in a rift setting, as inferred from thier petrology, Sr-Nd-Hf isotopes and regional tectonic evolution.

  13. El Granito Calasuya: un intrusivo alcalifeldespático postcolisional en el batolito de Sierra Norte-Ambargasta, Córdoba / The Calasuya Granite: a postcollisional alkalifeldspar intrusive in the Sierra Norte-Ambargasta batholith, Córdoba province

    Scientific Electronic Library Online (English)

    Javier, Elortegui Palacios; Raúl, Lira; Fernanda, Poklepovic; Michael J., Dorais.

    2008-09-01

    Full Text Available La zona central del extenso batolito Sierra Norte-Ambargasta, en el bloque más oriental de las Sierras Pampeanas orientales, está representada por granitoides de arco magmático tipo I (granodioritas, monzogranitos, pórfidos dacíticos y riolíticos denominados serie La Isla - Cerro de los Burros), int [...] ruidos por cuerpos menores félsicos postcolisionales, químicamente más evolucionados (denominados unidades Puesto de Los Caminos y Cerro Baritina), todos pertenecientes al Neoproterozoico- Cámbrico inferior. Nueva información geológica y geoquímica de la región centro-oriental del mismo batolito permitió identificar un plutón de composición alcalifeldespática, denominado Granito Calasuya, el primero de esta naturaleza en el batolito. Su mineralogía distintiva la constituyen la composición albítica de la plagioclasa magmática (An Abstract in english The central-western portion of the extended Sierra Norte-Ambargasta batholith, in the easternmost block of the eastern Sierras Pampeanas, is largely characterized by pre-collisional I-type magmatic arc granitoids (granodiorites, monzogranites, dacite and rhyolite porphyries named La Isla - Cerro de [...] los Burros series), and by smaller sized postcollisional felsic intrusives of higher evolved chemistry (named Puesto de los Caminos and Cerro Baritina units), all of which crystallized along the Late Proterozoic -Lower Cambrian time span. New geological and geochemical data from the central and oriental areas of the batholith allowed to identify an intrusive body of alkalifeldspar composition (the Calasuya granite), the first of its type in the batholith. Its distinctive mineralogy is highlighted by the albitic composition of magmatic plagioclase (molar An

  14. El Granito Calasuya: un intrusivo alcalifeldespático postcolisional en el batolito de Sierra Norte-Ambargasta, Córdoba The Calasuya Granite: a postcollisional alkalifeldspar intrusive in the Sierra Norte-Ambargasta batholith, Córdoba province

    Directory of Open Access Journals (Sweden)

    Javier Elortegui Palacios

    2008-09-01

    Full Text Available La zona central del extenso batolito Sierra Norte-Ambargasta, en el bloque más oriental de las Sierras Pampeanas orientales, está representada por granitoides de arco magmático tipo I (granodioritas, monzogranitos, pórfidos dacíticos y riolíticos denominados serie La Isla - Cerro de los Burros, intruidos por cuerpos menores félsicos postcolisionales, químicamente más evolucionados (denominados unidades Puesto de Los Caminos y Cerro Baritina, todos pertenecientes al Neoproterozoico- Cámbrico inferior. Nueva información geológica y geoquímica de la región centro-oriental del mismo batolito permitió identificar un plutón de composición alcalifeldespática, denominado Granito Calasuya, el primero de esta naturaleza en el batolito. Su mineralogía distintiva la constituyen la composición albítica de la plagioclasa magmática (An The central-western portion of the extended Sierra Norte-Ambargasta batholith, in the easternmost block of the eastern Sierras Pampeanas, is largely characterized by pre-collisional I-type magmatic arc granitoids (granodiorites, monzogranites, dacite and rhyolite porphyries named La Isla - Cerro de los Burros series, and by smaller sized postcollisional felsic intrusives of higher evolved chemistry (named Puesto de los Caminos and Cerro Baritina units, all of which crystallized along the Late Proterozoic -Lower Cambrian time span. New geological and geochemical data from the central and oriental areas of the batholith allowed to identify an intrusive body of alkalifeldspar composition (the Calasuya granite, the first of its type in the batholith. Its distinctive mineralogy is highlighted by the albitic composition of magmatic plagioclase (molar An < 6 %, the high #Fe (0.97 of accessory biotite, the presence of accessory late magmatic fluorite, and the conspicuous postmagmatic albitization process. Its highly fractionated nature is shown by high SiO2 and low CaO, MgO, TiO2, MnO and Fe2O3(t contents, also evidenced by Rb, Y and Th enrichment, and Sr, Ba and Zr depletion. The total REE content is low, showing asymmetric spider-type diagrams with predominance of LREE over HREE; positive Ce/Ce* anomalies as well as deep negative Eu/Eu* are also remarkable characteristics of this pluton. The Zr+Nb+Ce+Y versus Ga/Al ratio unequivocally displays its I-type highly fractionated signature. According to some field and geochemical patterns, the Calasuya granite gathers similarities with granites of the Puesto de los Caminos unit, which groups highly evolved postcollisional epizonal granitoids. Notwithstanding, despite these evidences, REE patterns and its accessory mineralogy reveal more affinity with the Cerro Baritina unit which is represented by Lower Cambrian syenogranitic aplites, interpreted together with other highly evolved granitoids as indicators of the Pampean orogeny closure.

  15. Origin and evolution of Pliocene Pleistocene granites from the Larderello geothermal field (Tuscan Magmatic Province, Italy)

    Science.gov (United States)

    Dini, A.; Gianelli, G.; Puxeddu, M.; Ruggieri, G.

    2005-04-01

    Extensive, mainly acidic peraluminous magmatism affected the Tuscan Archipelago and the Tuscan mainland since late Miocene, building up the Tuscan Magmatic Province (TMP) as the Northern Apennine fold belt was progressively thinned, heated and intruded by mafic magmas. Between 3.8 and 1.3 Ma an intrusive complex was built on Larderello area (Tuscan mainland) by emplacement of multiple intrusions of isotopically and geochemically distinct granite magmas. Geochemical and isotopic investigations were carried out on granites cored during drilling exploration activity on the Larderello geothermal field. With respect to the other TMP granites the Larderello intrusives can be classified as two-mica granites due to the ubiquitous presence of small to moderate amounts of F-rich magmatic muscovite. They closely resemble the almost pure crustal TMP acidic rocks and do not show any of the typical petrographic features commonly observed in the TMP hybrid granites (enclaves, patchy zoning of plagioclase, amphibole clots). On the basis of major and trace elements, as well as REE patterns, two groups of granites were proposed: LAR-1 granites (3.8-2.3 Ma) originated by biotite-muscovite breakdown, and LAR-2 granites (2.3-1.3 Ma) generated by muscovite breakdown. At least three main crustal sources (at 14-23 km depth), characterized by distinct ?Nd( t) and 87Sr/ 86Sr values, were involved at different times, and the magmas produced were randomly emplaced at shallow levels (3-6 km depth) throughout the entire field. The partial melting of a biotite-muscovite-rich source with low ?Nd( t) value (about -10.5) produced the oldest intrusions (about 3.8-2.5 Ma). Afterwards (2.5-2.3 Ma), new magmas were generated by another biotite-rich source having a distinctly higher ?Nd( t) value (-7.9). Finally, a muscovite-rich source with high ?Nd( t) (about -8.9) gave origin to the younger group of granites (2.3-1.0 Ma). The significant Sr isotope disequilibrium recorded by granites belonging to the same intrusion is interpreted, as due to the short residence time of magmas in the source region followed by their rapid transfer to the emplacement level. Partial melting was probably triggered by multiple, small-sized mafic intrusions, distributed over the last 3.8 Ma that allowed temporary overstepping of biotite- and muscovite-dehydration melting reactions into an already pre-heated crust. Dilution in time of the magmatic activity probably prevented melt mingling and homogenization at depth, as well as the formation of a single, homogeneous, hybrid pluton at the emplacement level. Moreover the high concentrations of fluxing elements (B, F, Li) estimated for the LAR granites modified melt properties by reducing solidus temperatures, decreasing viscosity and increasing H 2O solubility in granite melts. The consequences were a more efficient, fast, magma extraction and transfer from the source, and a prolonged time of crystallization at the emplacement level. These key factors explain the long-lived hydrothermal activity recorded in this area by both fossil (Plio-Quaternary ore deposits) and active (Larderello geothermal field) systems.

  16. Interacción termal entre magmas graníticos laramídicos y rocas encajonantes mesoproterozoicas: Historia de enfriamiento de intrusivos de la Sierrita Blanca, NW Sonora / Thermal interaction between Laramide granitic magmas and Mesoproterozoic country rocks: thermochronology of intrusives of Sierrita Blanca, NW Sonora

    Scientific Electronic Library Online (English)

    Mónica A., Enríquez-Castillo; Alexander, Iriondo; Gabriel, Chávez-Cabello; Michael J., Kunk.

    2009-12-01

    Full Text Available Un estudio termocronológico semi-cuantitativo, combinando técnicas geocronológicas de U-Pb y 40Ar/39Ar, permitió evaluar el fenómeno de cristalización y posterior enfriamiento del cuerpo intrusivo laramídico Sierrita Blanca, así como el efecto termal del mismo en las rocas encajonantes mesoproterozo [...] icas (~1.1 Ga) denominadas granito Murrieta. La disparidad en edades U-Pb en zircones para dos muestras del granito Sierrita Blanca (72.6 ± 1.2 Ma y 69.7 ± 1.0 Ma) pudiera estar asociada al enfriamiento más rápido del magma en la zona de contacto con el encajonante mesoproterozoico; pero no se puede descartar que esta unidad granítica esté compuesta por múltiples intrusiones de composición similar y relativamente espaciadas en el tiempo. Las edades de 40Ar/39Ar (biotita y feldespato potásico) de la muestra de granito más cercana al encajonante son también más antiguas que las de la roca recolectada en la zona más interna del intrusivo. El enfriamiento inicial del granito es relativamente rápido desde la temperatura de cierre del zircón hasta la de la biotita (~36-32°C/Ma), para que posteriormente se pase a enfriamientos relativamente lentos desde la biotita hasta el feldespato potásico (~10-9°C/Ma). Estos enfriamientos del granito Sierrita Blanca son comparables, aunque quizá un poco más lentos, a los estimados para otros granitoides laramídicos del NW de México. Tres muestras del granito mesoproterozoico Murrieta, recolectadas a diferentes distancias del intrusivo laramídico, fueron fechadas por U-Pb en zircones (~1.1 Ga), reiterándose la resistencia de esta sistemática a los efectos termales. Sin embargo, se aprecia la presencia de zircones con pérdida evidente de Pb, que se asocian a la exposición de estas rocas al calor y/o fuidos relacionados a la intrusión laramídica, siendo este efecto más pronunciado en la roca recolectada cerca del contacto con el granito. Este efecto de reajuste isotópico es mucho más marcado para la sistemática de 40Ar/39Ar en biotita y feldespato potásico, al encontrarse estos minerales totalmente reajustados a edades laramídicas. Las estimaciones de enfriamiento post-reajuste isotópico entre biotita y feldespato potásico (~18-15°C/Ma) de las rocas encajonantes son, en cierto modo, armónicas con los enfriamientos estimados para estos mismos minerales en el granito laramídico. Esto sugiere que el enfriamiento general del área de la Sierrita Blanca, después de la intrusión granítica lara-mídica, fue coherente, fnalizando este en las zonas más internas del intrusivo. Por último, destacar que el pulso magmático miocénico presente en la Sierrita Blanca no ha causado ningún efecto termal apreciable en las rocas graníticas cretácicas o mesoproterozoicas. Abstract in english A semi-quantitative thermochronological study, combining U-Pb and 40Ar/39Ar geochronology, has allowed assessment of the crystallization and cooling history of the Laramide Sierrita Blanca granite as well as the thermal effects resulting from the intrusion into the Mesoproterozoic host rocks (~1.1 G [...] a Murrieta granite). The U-Pb zircon age discrepancy between two samples of the Sierrita Blanca granite (72.6 ± 1.2 Ma and 69.7 ± 1.0 Ma) could be explained by a process of faster magma cooling in the contact zone with the host Murrieta granite. However, that the Sierrita Blanca granitic unit was made up of multiple intrusions of similar compositions emplaced relatively close in time cannot be discarded. The 40Ar/39Ar ages of both biotite and K-feldspar for the granite collected close to the contact are also signifcantly older than the ages for the sample collected in a more internal zone of the intrusion. The initial cooling of the Sierrita Blanca granite was fairly fast and monotonous from the closure temperature of zircon to that of biotite (~36-32°C/Ma). Subsequently, the cooling of these Laramide rocks became relatively slow (~10-9°C/Ma) between the closure temperature of biotite and K-feldspar. These estimated cooling rates are similar, pe

  17. Geology of a Transect Across a Mesoproterozoic Anorthosite - Granite Batholith, Nain, Northern Labrador

    Science.gov (United States)

    Myers, J.

    2004-05-01

    A five year research project at Memorial University, supported by VBN/INCO and NSERC, is studying the geology of a transect across the Nain Plutonic Suite to better understand the geological setting of the Voisey's Bay Ni-Cu-Co deposit. This study is based on new geological mapping at a scale of 1:20 000, completed between 1999-2003 by Furlong, Gaskill, Goddard, Rawlings-Hinchey, Myers, Tettelaar, Voordouw and Wright. The talk outlines the regional geology determined by this collective study in a transect 80 km long and 40 km wide. The Nain Plutonic Suite forms a batholith comprising numerous plutons, dykes and sheets of anorthosite, leuconorite, leucotroctolite, troctolite, ferrodiorite, monzonite and granite. The batholith is 70 km wide and over 200 km long and was emplaced from 1360 to 1290 Ma along a 1860 Ma suture between two Archean continents. Within the Nain Plutonic Suite, pluton and dyke emplacement was associated with intermittent extension and transcurrent movements on east-west and NNW-SSE faults. During successive emplacement, older structures tended to be reactivated by younger intrusions. The same kinds of magmas were intruded intermittently throughout the development of the batholith. In many cases, intrusion was accompanied by fragmentation of the adjacent wall and roof rocks, and probably involved cauldron subsidence. Anorthosite and granite form large tabular plutons whereas composite ferrodiorite-monzonite intrusions mostly form arcuate dykes, small circular plutons, or narrow remnants in the margins of large anorthosite plutons. Relatively small amounts of troctolite mainly form sheet-like bodies. There is an overall longitudinal asymmetry to the batholith with rapakivi granite predominant in the west and anorthosite in the east. The anorthosite is further spatially divided into older, partly deformed and recrystallized anorthosite and leuconorite in the west and north, and younger, undeformed and unrecrystallized anorthosite and leucotroctolite in the east and south.

  18. Granite genesis

    CERN Document Server

    Chen, Guo-Neng

    2007-01-01

    Provides a synthesis of current ideas of granite genesis in the earth's crust developed over the last 20 yearsProvides an alternative model for granite genesis and a reinterpretation of current ideasHighlights results of Chinese research (published in Chinese) over the last 30 years in English for the first time

  19. From explosive breccia to unidirectional solidification textures: magmatic evolution of a phosphorus- and fluorine-rich granite system (Podlesí, Krušné hory Mts., Czech Republic

    Directory of Open Access Journals (Sweden)

    Breiter K

    2002-06-01

    Full Text Available The Podlesí granite stock in western Krušné hory Mts. represents the most highly fractionated part of the late Variscan Nejdek-Eibenstock pluton. Internal fabric of the stock has been studied in several boreholes up to 350 m deep. The stock is composed of two tongue-like bodies of albite-protolithionite-topaz granite (stock granite coalesced at depth, which were emplaced into Ordovician phyllite and biotite granite of younger intrusive complex (YIC of the Nejdek pluton. The uppermost part of the intrusion is bordered by a layer of marginal pegmatite (stockscheider up to 50 cm thick. Explosive breccia was found as an isolated block at the southwest contact of the stock. It is comprised of fragments of phyllite several millimetres to 5 cm in size cemented with fine-grained granitic matrix similar to the stock granite, but very fine-grained.
    Within the uppermost 100 m, the stock granite is intercalated with several mostly flat-lying dykes of albite-zinnwaldite-topaz granite (dyke granite. Upper and lower contacts of the dykes are sharp, flat, but in detail slightly uneven. The thickest dyke (about 7 m outcrops in an old quarry. A prominent example of layering with unidirectional solidification textures (UST was found in the upper part of this major dyke. Individual Q-Afs laminae are separated by comb quartz layers and/or by layers of oriented fan-like zinnwaldite aggregates. A pegmatite-like layer with oriented megacrysts of Kfs up to 6 cm long was encountered in the uppermost part of the dyke. One thin layer of fine-grained quartz with oriented Kfs-megacrysts was found within the stock granite.
    Post-magmatic processes, particularly greisenisation, developed only to a limited degree. The uppermost flat dyke of the dyke granite was partly greisenised into white quartz-rich (+topaz, Li-mica, wolframite greisen. Scarce thin, steep stringers of biotite greisen were encountered over the entire outcrop and in drilled parts of the stock granite and surrounding biotite granite.

  20. The search for the youngest granites in the southern part of the Natal Metamorphic Province

    International Nuclear Information System (INIS)

    It is clear that the Belmont Pluton and the dykes are geochemically, isotopically and therefore, genetically distinct. The Belmont pluton is probably related to the garnet leucogranite phase of the Margate Complex. It is suggested that the dykes (? 965 Ma) are younger than the Belmont pluton (?1055 Ma). The relatively low initial 87Sr/86Sr are typical of the granites intruded at ?1000 Ma. The age of the dykes is comparable with the 951 ± 16 Ma (Ro=.70320 ± 13) given for the Sezela pluton. The high Ro (?0.715) of the dykes is similar to other, minor granite sheets from southern Natal, and is compatible with an origin by late-stage melting of pre-existing radiogenic material. Both the dykes and the Sezela pluton are unequivocally younger than the D3 deformation, whereas the young dates from the Oribi Gorge Suite are controversial. Thus, although it is possible that some of the minor, intrusive granitic sheets could yet be shown to be of Pan-African age, it is evident that no significant Pan-African magmatism or thermal overprinting has affected the Natal sector of the Namaqua-Natal-Maudheim belt. 1 fig., 7 refs

  1. The petrogenesis of a wolframite-bearing greisen in the Vykmanov granite stock, Western Krušné hory pluton (Czech Republic

    Directory of Open Access Journals (Sweden)

    Štemprok M

    2005-09-01

    Full Text Available A wolframite-bearing greisen at Vykmanov, near Ostrov (Czech Republic occurs at the contact of a small granite stock belonging to the Late Variscan Younger Intrusive Complex (YIC of the Western Krušné hory/Erzgebirge pluton. The stock emerges as an outcrop of 0.8 × 0.3 km size from a hidden granite body in the eastern continuation of the Nejdek-Eibenstock granite massif. The lens-like greisen body consists mainly of quartz, topaz, protolithionite, and muscovite; it also contains wolframite (ferberite and native bismuth mineralization. It was formed by replacement of a medium-grained, equigranular, slightly porphyritic Li-F granite of the Karlovy Vary pluton characterized by weak postmagmatic albitization and pervasive muscovitization. The greisen is geologically and compositionally transitional between the Li-rich greisens in albite granites (e.g. with zinnwaldite such as at Krásno and the Li-poor greisens (e.g. phengite greisens at Gottesberg and P?ebuz associated with weakly albitized granites of the Younger Intrusive Complex. The Vykmanov greisen formed in a subsolidus stage of granite evolution by progressive alkali loss and fluorine metasomatism, leading to the formation of Li-mica quartz greisen subsequently replaced by topaz-quartz greisen at the granite/crystalline contact. These greisens were affected by late-stage muscovitization and argillitization (sericitization, the formation of clay minerals. The Li-Fe mica composition of the greisens corresponds to protolithionite (lithian siderophyllite and is similar to the composition of micas in the enclosing granite. The tungsten-bearing greisenization represents a postmagmatic episode in the development of the Krušné hory/Erzgebirge batholith, and is located at the eastern contact of highly evolved YIC granites of the Western Krušné hory pluton. The greisen formed from CO2 -poor hydrothermal solutions, at about 400 °C, which evolved from highly saline brines as evidenced by fluid inclusion studies. The geological situation suggests that the mineralizing fluids were mostly magmatic and were responsible for the tungsten-bismuth specialization of the greisens, whereas meteoric waters participated in mineralization during later stages.

  2. Petrographic and mineralogical features of the uraniferous pink granites in the north eastern desert of egypt

    International Nuclear Information System (INIS)

    The present work is concerned with the petrological, mineralogical and geochemical studies of some uranium bearing younger granites in the north eastern desert of egypt particularly Gebel Gattar area. The area around Gebel Gattar comprises the following rock units (starting from the oldest): meta volcanic, diorite-grano-diorite complex- Dokhan volcanics- Hammamat sediments, younger granites and dykes. The most significant structural features are represented by NNE-ENE dominantly trending faults and joints. Petrographicaly, the pink granites are divided into normal and mineralized (uraniferous) granites. Normal granites are classified into three types; a) leucocratic perthitic granite, b) hornblende- biotite perthitic granite and c) two feldspars perthitic granite. Mineralized granites are sheared, deformed, pinkish brown in colour and strongly altered. A remarkable secondary uranium mineralization has been recorded along fault and fracture zones

  3. Granites of southeast Asian tin belt

    Energy Technology Data Exchange (ETDEWEB)

    Cobbing, E.J.; Mallick, D.I.J.; Pitfield, P.E.J.; Darbyshire, D.P.F.; Teoh, L.H.

    1986-07-01

    The objective of this study is to establish the essential granite geology of the southeast Asian tin belt, distinguishing plutons within batholiths and characterizing them by their component units, field relationships, lithology, texture, petrology, geochemistry, geochronology, and mineral potential. To date, approximately 180 plutons have been recognized and partly or entirely described in the above terms. In addition, four granite provinces have been delineated, each with its own distinctive mineralization pattern. In all provinces, but particularly in the Main Range, granitoids designated as two-phase variants have been recognized where xenocrysts and xenoliths of coarse, primary texture granite are enclosed in and corroded by an invasive, equigranular quartzo-feldspathic matrix. These rocks form an essential part of the granite sequence in all provinces and have probably resulted from the infiltration and disruption of the host granite by late-stage magmatic fluids. Whole-rock geochemistry from peninsular Malaysia shows that the granites from the Main Range and Eastern provinces comprise two contrasted suites, which correspond approximately to the I- and S-type categories advocated by Chappell and White. In addition, individual plutons within batholiths in the two provinces have distinct geochemical parameters. Variation diagrams of plutons having the intrusive sequence primary texture granite-two-phase granite-microgranite show linear trends with increasing SiO/sub 2/, Na/sub 2/O, Rb, W, Sn, and U, and decreasing Sr, Ba, Th, and all other major elements.

  4. Ad Duwayhi, Saudi Arabia: Geology and geochronology of a neoproterozoic intrusion-related gold system in the Arabian shield

    Science.gov (United States)

    Doebrich, J.L.; Zahony, S.G.; Leavitt, J.D.; Portacio, J.S., Jr.; Siddiqui, A.A.; Wooden, J.L.; Fleck, R.J.; Stein, H.J.

    2004-01-01

    The Ad Duwayhi gold deposit, located in the east-central part of the Arabian shield, is the newest gold discovery in Saudi Arabia. Exploration to date has identified a gold resource of greater than 1 million ounces (oz) with significant potential for expansion. Gold mineralization was closely associated, in time and space, with emplacement of a late- to postorogenic, intracrustal, northwest-oriented granite body (659 ?? 7 Ma) and comagmatic square quartz porphyry (646 ?? 11 Ma), a hypabyssal and perhaps younger phase of the granite. Mineralization was largely confined to northeast-striking, southeast-dipping fault zones. Hydrothermal alteration consisted of early biotitic alteration overprinted by sericitic alteration. Sericitic alteration was coincident with gold mineralization and produced a quartz-sericite-carbonate-pyrite-rutile mineral assemblage, found both as vein fill and wall-rock alteration products. Mineralization styles, in the following general paragenetic sequence, include (1) quartz-molybdenite veins in and near the granite stock, (2) low-grade gold-bearing quartz vein breccia in and along the margins of the granite stock, (3) gold-bearing stockwork and sheeted quartz veins, and (4) massive to banded gold-rich tabular quartz veins. The gold-bearing stockwork, sheeted, and tabular veins are generally spatially associated with square quartz porphyry dikes and more distal to the granite stock. Mineralized zones at Ad Duwayhi are characterized by low sulfide and base metal content and gold/silver ratios of approximately 6/1. Gold shows no significant correlation with other metals, except lead, and moderate correlation with silver. Re-Os dating of molybdenite from a quartz-molybdenite vein and a tabular quartz vein with cogenetic gold produced robust ages of 655.6 ?? 2.7 and 649.9 ?? 2.3 Ma, respectively, documenting that gold mineralization and crystallization of granite and square quartz porphyry were, within uncertainty, coeval events. This age correlation combined with granite textural features, the presence of unidirectional solidification textures in granite and square quartz porphyry, and the nature and time-space distribution of mineralization styles, all indicate that mineralization evolved in and near the interface between a crystallizing magma and the surrounding rocks and, thus, is consistent with an intrusion-related genesis. In light of our findings at Ad Duwayhi, a reassessment of similar intrusion-hosted deposits in the Arabian shield is warranted, and areas of late- to postorogenic plutonism, particularly in the Afif composite terrane, should be considered prospective for intrusion-related gold systems. ??2004 by Economic Geology.

  5. Analysis of microporous structure in granite

    International Nuclear Information System (INIS)

    The water saturation method and the mercury intrusion porosimetry were applied to the characterization of micropores in granite. Although these techniques have been commonly used to characterize pores in rocks, special cares are needed for precise measurement of the porosity and the pore size of low-porosity rocks. The water saturation method uses water-saturated weight, submerged weight and dry weight of the rock samples to calculate the porosity. The errors accompanied in the measurements of the water-saturated weight often bring about significant errors in determination of the porosity. Analysis of drying curves of water-saturated weight enabled precise measurements of porosity. In the mercury intrusion porosimetry, a major part of the error in the porosity determination is due to rough surfaces of the sample. For the porosity determination described in this paper, the rock sample was cut into rectangular parallelepipeds, instead of crushing, to reduce the surface roughness. The detection limit of the mercury intrusion is also a cause for the error for low-porosity samples. Five samples whose total volume was 6ml were simultaneously put in the measurement cell of the porosimeter to increase the amount of intruding mercury. These effort made reliable characterization of pores in a granite from Inada, Ibaraki, Japan and pores in a granite from the Underground Research Laboratory (URL) of Atomic Energy of Canada Limited, Manitoba, Canada. The distribution of the pore oba, Canada. The distribution of the pore diameter of these granites were nearly logarithmic normal. The porosity of Inada granite was determined to be (0.49±0.07)% with the modal diameter of 160nm. The micropores of a few tens to a few hundred nanometers in width were observed by SEM. The URL granite had the porosity of (0.40±0.10)% and the modal diameter of 340nm. The assumptions in applying the Fickian diffusion theory to the diffusion of ions in porous materials were confirmed for these granites. (J.P.N.)

  6. Uranium in granites

    International Nuclear Information System (INIS)

    Recent research activities of the Canadian Uranium in Granites Study are presented in 18 papers and 3 abstracts. 'Granites' is used as a generic term for granitoids, granitic rocks, and plutonic rocks

  7. The uranium, thorium and molybdenum distribution in selected leucogranites of the Cape-granite-suite

    International Nuclear Information System (INIS)

    Younger intrusions and hydrothermally altered rocks like alkali granite, alaskite, syenite and episyenite resembling uranium ore deposits in France and the Roessing ore body in SWA/Namibia are found within the Saldanha and Darling batholiths of the south-western Cape Province. Two areas were geologically mapped in detail and surveyed with a portable gamma spectrometer in order to establish the regional variation in U and Th concentration. A quantitative study of alpha particle tracks on autoradiographs of selected thin sections led to the determination of the contributions by various minerals to the U and Th content of each individual rock type. The rocks were also investigated petrologically and geochemically with special attention to secondary alteration processes that could have played a part in causing the distribution pattern of U and Th. Radioelement analyses of 45 mineral separates and 51 whole rock analyses were utilised

  8. Rb-Sr and Pb-Pb geochronological studies on the granite gneiss of Kuilapal, Purulia-Bankura Midnapore district, West Bengal

    International Nuclear Information System (INIS)

    The number of younger granite plutons intruding the Singhbhum Mobile Belt (SMB) surrounding the Singhbhum-Orissa Craton, viz. Kuilapal granite on the East, Mayurbhanj granite, Soda granite, Arkasoni granite, Chakradharpur granite gneiss and Tamper kola granite on the west. Of these Kuilapal granite body is the largest. Besides small granite bodies intruding the low-grade meta sediments and meta volcanics which occur north of the Dalma volcanic belt. Petrographic and geochemical characters of the minor granite bodies south of Dalma volcanics are similar to those of Kuilapal granite, which is inferred to have been produced by shallow-level fractional crystallisation of a crustally derived granodiorite melt. Dominance of xenoliths in the Kuilapal granite suggest large-scale assimilation of crustal rocks. The radiometric ages vis-a-vis isotope geochemistry of the various granitoid plutons occurring within the mobile belt were used to constrain the evolutionary history of the SMB supracrustals. The Singhbhum Shear Zone which marks the boundary of the SMB with Singhbhum-Orissa Craton, shows multiple reactivation, the oldest being at ? 3.09Ga. Further phases of granite plutonism and/or shearing and mineralisation have been reported along this shear zone occurred in Palaeo-to Mesoproterozoic periods at ? 2.2, 1.8, 1.6-1.5, 1.4 and 1.0 Ga respectively. The present work pertains to the Rb-Sr and Pb-Pb whole rock geochronological studies on Kuilapal granite, which are intrus on Kuilapal granite, which are intrusive into the metasediments of Singhbhum group in the tectonic setup of north Singhbhum Mobile Belt. Fourteen samples were collected, finely powdered form the homgenised representative which were processed further. The dissolution of the rock carried out in a class-100 clean chemical laboratory, followed by the elemental separation using exchange chromatography. The separated pure fractions of the elements were analysed on VG354 Thermal Ionisation Mass spectrometer for their isotopic ratios. The Rb-Sr data on ten samples define an isochron age of 1792±98 Ma, with an initial 87Sr/86Sr of 0.7064±0.0069 (MSWD = 13). The Pb isotopic data on these samples define a Pb-Pb isochron age of 1863 ± 80Ma (MlSWD =11.3) with a model ?1 value of 8.53±0.27. Both the Rb-Sr and the Pb-Pb ages are in agreement within the limits of experimental errors. Since the 87Sr/86Sr initial ratio and model ?1 value are higher than the contemporary mantle sources, the data indicate involvement of enriched crustal sources. This age obtained on Kuilapal granite can be taken as the age of one of those periods of reactivation which occurred during Palaeo-to Mesoproterozoic periods. (author)

  9. 2005 dossier: granite; Dossier 2005: granite

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    This document makes a status of the researches carried out by the French national agency of radioactive wastes (ANDRA) about the geologic disposal of high-level and long-lived radioactive wastes in granite formations. Content: 1 - advantage of granitic formations for the geologic disposal; 2 - containers; 3 - design study of a disposal facility in granitic environment; 4 - understanding and modelling of granite; 5 - description of disposal concepts in granitic environment; 6 - long-term and safety aspects; 7 - conclusion. (J.S.)

  10. The age of the Baerhalde Granite (Black Forest) and the uranium deposit of Menzenschwand

    International Nuclear Information System (INIS)

    Rb/Sr total-rock dating of intrusive rocks in the Southern Black Forest yielded ages of 290 +- 6 my (my = millions of years) for the Baerhalde Granite, 315 +- 10 my for the Schluchsee Granite and 274 +- 7 my for the porphyry cutting both granites. Biotite and muscovite Rb/Sr and K/Ar-dates however yielded ages of 325 +- 3 my. Further total rock analyses of the Baerhalde Granite presented in this paper reconfirmed the total rock age previously published and they did not eliminate the discrepancy between the younger total-rock- and the older mineral-ages. Pb/U-dates of two pitchblende-samples from the Krunkelbachtal near the village of Menzenschwand yielded ages of 230 my which were already published previously. Re-analyses of these samples reconfirmed these U/Pb-dates which also agreed with additional 210Pb-dates. However two additional samples of pitchblende yielded higher Pb/U-ages which also are highly discordant in respect to U/Pb and 210Pb-ages indicating a disturbance of the radioactive equilibrium caused by geochemical processes in most recent times. The 207Pb/206Pb-ages of all samples are considerably higher at about 300 my. Although the value of these dates is restricted because of the wide limits of error of this method at young ages, too young Pb/U-ages due to lead loss may be possible. A real age of the U-mineralisation of about 300 my therefore can not be excluded. (orig.))

  11. Tectono-magmatic evolution of the younger Gardar southern rift, South Greenland

    Directory of Open Access Journals (Sweden)

    Brian G.J. Upton

    2013-11-01

    Full Text Available The 1300–1140 Ma Gardar period in South Greenland involved continental rifting, sedimentation and alkaline magmatism. The latest magmatism was located along two parallel rift zones, Isortoq–Nunarsuit in the north and the Tuttutooq–Ilimmaasaq–Narsarsuaq zone in the south addressed here. The intrusive rocks crystallised at a depth of <4 km and are essentially undisturbed by later events. Magmatism in the southern zone began with the emplacement of two giant, ?800 m wide dykes and involved intrusion of transitional olivine basaltic, high Al/Ca magmas crystallising to troctolitic gabbros. These relatively reduced magmas evolved through marked iron enrichment to alkaline salic differentiates. In the Older giant dyke complex, undersaturated augite syenites grade into sodalite foyaite. The larger, c. 1163 Ma Younger giant dyke complex (YGDC mainly consists of structureless troctolite with localised developments of layered cumulates. A layered pluton (Klokkenis considered to be coeval and presumably comagmatic with the YGDC. At the unconformitybetween the Ketilidian basement and Gardar rift deposits, the YGDC expanded into a gabbroic lopolith. Its magma may represent a sample from a great, underplated mafic magma reservoir, parental to all the salic alkaline rocks in the southern rift. The bulk of these are silica undersaturated; oversaturated differentiates are probably products of combined fractional crystallisation and crustalassimilation.A major dyke swarm 1–15 km broad was intruded during declining crustal extension, with decreasing dyke widths and increasing differentiation over time. Intersection of the dyke swarm and E–W-trending sinistral faults controlled the emplacement of at least three central complexes (Narssaq, South Qôroq and early Igdlerfigssalik. Three post-extensional complexes (Tugtutôq,Ilímaussaq and late Igdlerfigssalik along the former rift mark the end of magmatism at c. 1140 Ma. The latter two complexes have oblate plans reflecting ductile, fault-related strain. The Tugtutôqcomplex comprises quartz syenites and alkali granites. The Ilímaussaq complex mainly consists of nepheline syenite crystallised from highly reduced, Fe-rich phonolitic peralkaline (agpaitic magma,and resulted in rocks with very high incompatible element concentrations.Abundant anorthositic xenoliths in the mafic and intermediate intrusions point to a large anorthosite protolith at depth which is considered of critical importance in the petrogenesis of the salicrocks. Small intrusions of aillikite and carbonatite may represent remobilised mantle metasomites. The petrological similarity between Older and Younger Gardar suites implies strong lithospheric control of their petrogenesis. The parental magmas are inferred to have been derived from restitic Ketilidian lithospheric mantle, metasomatised by melts from subducting Ketilidian oceanic crust and by small-scale melt fractions associated with Gardar rifting.There are numerous analogies between the southern Gardar rift and the Palaeogene East Africanrift.

  12. Review of engineering, hydrogeological and vadose zone hydrological aspects of the Lanseria Gneiss, Goudplaats-Hout River Gneiss and Nelspruit Suite Granite (South Africa)

    Science.gov (United States)

    Dippenaar, Matthys A.; van Rooy, J. Louis

    2014-03-01

    Three major basement granites of South Africa, viz. the Lanseria Gneiss of the Johannesburg Dome Granite, the Goudplaats-Hout River Gneiss and the Nelspruit Suite, are compared in terms of existing and new geotechnical and hydrogeological data. Typical weathering profiles based on landform and climate are deduced, denoting typical engineering and hydrogeological behaviour. Finally, the vadose zone behaviour of the basement granites are described with the aim on better understanding of the behaviour of these systems under variable saturation. Ephemeral hillslope wetlands, seepage lines and catenas are specifically addressed as associated hydrological influences, as well as the associated processes of translocation forming duplex soils and pedogenesis forming ferricrete. The final summarised findings depict low plasticity and expansiveness of granites with the most notable geotechnical influences being collapsibility, dispersive behaviour, seepage and difficult excavation. Hydrologically, secondary porosity prevails and younger structures or intrusions govern groundwater occurrence. The vadose zone comprises thick fractured rock to be included in modelling with the soil zone having saturated conductivity typically in the order of 1 × 10-4 to 1 × 10-5 m/d.

  13. Pórfiro granítico Mojotoro (Salta: ¿Una cúpula intrusiva o un dique en el ciclo pampeano? The Mojotoro granitic porphyry (Salta: An intrusive roaf or a dike in the Pampean Cycle?

    Directory of Open Access Journals (Sweden)

    A.J. Toselli

    2005-06-01

    Full Text Available El pórfiro granítico Mojotoro, constituye la cúpula de un plutón epizonal, emplazado en un área geológica bien conocida, de la Formación Puncoviscana, en las inmediaciones de la ciudad de Salta (24º47´44,9"S - 65º21´35,9"W, 1.304 m s.n.m.. Sin bien se carece de determinaciones geocronológicas, los caracteres geológicos regionales y situación estratigráfica de no alcanzar los niveles del Grupo Mesón, sugieren edades pampeanas, correspondientes a la orogenia tilcárica. Los caracteres petrográficos corresponden a pórfiros graníticos, con fenocristales de feldespato potásico, acompañados por cuarzo, plagioclasa y biotita. Las rocas han sufrido intensa sericitización, caolinización y limonitización. Asimismo muestra esferulitas recristalizadas, inclusiones fluidas y fragmentos de granófiro, que indican emplazamiento somero, con rápido intercrecimiento conjunto de cuarzo en una masa de feldespato alcalino hipersolvus. La susceptibilidad magnética es baja con valores de 0,11 x 10-3 SI, típicos para granitos corticales formados a partir de protolitos metasedimentarios.The Mojotoro porphyritic granite is located close to the city of Salta (24°47´44,9"S - 65°21´35,9"W, 1304 m.a.s.l., at Cerro Mojotoro in the Eastern Cordillera. The pluton is emplaced in the Puncoviscana Formation (Late Precambrian-Early Cambrian, a lithological unit composed mainly of greenish pelites. The Puncoviscana Formation is covered unconformably by Cambrian quartzites of the Meson Group. Stratigraphic relationships of the granite indicate a Pampean age and emplacement during the Tilcaric orogenic phase. Petrographically it is a porphyritic granite with K-feldspar phenocrysts accompanied by quartz, plagioclase and biotite. The rock is strongly altered by sericitization, kaolinization, and limonitization. Likewise, the granite exhibits recrystalized spherules, fluid inclusions and granophyric fragments, indicative of shallow emplacement, with fast intergrowth of quartz in a mass of K-feldspar hypersolvus. Low magnetic susceptibility, with values of 0.11x10-3 SI, is typical of cortical granite that was formed from a metasedimentary protolith.

  14. Nature of the Yucatan Block Basement as Derived From Study of Granitic Clasts in the Impact Breccias of Chicxulub Crater

    Science.gov (United States)

    Vera-Sanchez, P.; Rebolledo-Vieyra, M.; Perez-Cruz, L.; Urrutia-Fucugauchi, J.

    2008-05-01

    The tectonic and petrologic nature of the basement of the Yucatan Block is studied from analyses of basement clasts present in the impact suevitic breccias of Chicxulub crater. The impact breccias have been sampled as part of the drilling projects conducted in the Yucatan peninsula by Petroleos Mexicanos, the National University of Mexico and the Chicxulub Scientific Drilling Project. Samples analyzed come mainly from the Yaxcopoil-1, Tekax, and Santa Elena boreholes, and partly from Pemex boreholes. In this study we concentrate on clasts of the granites, granodiorites and quartzmonzonites in the impact breccias. We report major and trace element geochemical and petrological data, which are compared with data from the granitic and volcanic rocks from the Maya Mountains in Belize and from the Swannee terrane in Florida. Basement granitic clasts analyzed present intermediate to acidic sub-alkaline compositions. Plots of major oxides (e.g., Al2O3, Fe2O3, TiO2 and CaO) and trace elements (e.g., Th, Y, Hf, Nb and Zr) versus silica allow separation of samples into two major groups, which can be compared to units in the Maya Mountains and in Florida basement. The impact suevitic breccia samples have been affected by alteration likely related to the hydrothermal processes associated with the crater melt sheet. Cloritization, seritization and fenitization alterations are recognized, due to the long term hydrothermalism. Krogh et al. (1993) reported U-Pb dates on zircons from the suevitic breccias, which gave dates of 545 +/- 5 Ma and 418 +/- 6 Ma, which were interpreted in terms of the deep granitic metamorphic Yucatan basement. The younger date correlates with the age for the Osceola Granite and the St. Lucie metamorphic complex of the Swannee terrane in the Florida peninsula. The intrusive rocks in the Yucatan basement may be related to approx. 418 Ma ago collisional event in the Late Silurian.

  15. Geochronology of granitic rocks from the Ruangwa region, southern Tanzania - Links with NE Mozambique and beyond

    Science.gov (United States)

    Thomas, Robert J.; Bushi, Alphonce M.; Roberts, Nick M. W.; Jacobs, Joachim

    2014-12-01

    New U-Pb zircon LA-ICP-MS data are presented for 4 granitoid bodies which intrude high grade gneisses of the previously unmapped Ruangwa region in southern Tanzania. The study area forms part of the late Neoproterozoic East African Orogen (EAO). The oldest unit, a coarse-grained migmatitic granitic orthogneiss gave an early Neoproterozoic (Tonian) crystallization age of 899 ± 9/16 Ma, which is similar to, but significantly younger than, Stenian-Tonian basement ages in areas relatively nearby. Crust of this age may extend as far north as the major Phanerozoic Selous Basin, north of which Archaean protolith ages predominate (the "Western Granulites"), except for the juvenile Neoproterozoic "Eastern Granulites", which are not represented in the study area. To the south, the Tonian crust of the study area provides a tentative link with the Marrupa Complex in NE Mozambique. A granite pluton, dated at 650 ± 5/11 Ma is broadly coeval with the main Pan-African tectono-thermal event in the East African Orogen that is recorded across Tanzania north of the Selous Basin. Zircons in this granite contain inherited cores at ca. 770 Ma. This age is within the range of dates obtained from south and west of the study area from juvenile granitoid orthogneisses which might be related to a widespread, but poorly understood, early phase of Gondwana assembly along an Andean-type margin. South of the study area, in NE Mozambique, the latest orogenic events occurred at ca. 550 Ma, and are sometimes attributed to the Ediacaran-aged "Kuunga Orogeny". While metamorphic dates of this age have been recorded from the EAO north of the Selous Basin, magmatic rocks of this event have not been recognized in Tanzania. The two youngest granitoids of the present study are thus the first 500-600 Ma igneous rocks reported from the region. A weakly deformed very coarse-grained granite pluton was dated at 591 ± 4/10 Ma, while a very late, cross-cutting, undeformed granite dyke gave an intrusive age of 549 ± 4/9 Ma. The granitoids ages presented in this study contain elements that are characteristic of the northern, Tanzania-Kenya, segment of the East African Orogen and of the southern, Mozambique, segment. The Tonian orthogneiss sample is typical of (but somewhat younger than) the Marrupa Complex of NE Mozambique. No zircon inheritance was recorded in the sample, typical of the juvenile Marrupa Complex. On the other hand, the ca. 650 Ma granite pluton has an age that is typical of the northern segment of the orogen; this is the first recorded granite of that age intruded into the Tonian-dominated crust of southern Tanzania or NE Mozambique. The two younger granites have provided dates that are typical of the southern segment of the orogen, and that of the Kuunga Orogen. The study area thus appears to represent an area of transitional crust straddling two complex and contrasting segments of the East African Orogen, with elements of both segments present and evidence for a ca. 770 Ma event which appears to be quite widespread and may relate to the early phases of Gondwana amalgamation in southern East Africa.

  16. Petrography and geochemistry of the topaz-bearing granite stocks in Artjärvi and Sääskjärvi, western margin of the Wiborg rapakivi granite batholith

    Directory of Open Access Journals (Sweden)

    Sari Lukkari

    2002-01-01

    Full Text Available The Artjärvi and Sääskjärvi granite stocks at the western margin of the Wiborg rapakivi batholith are multiphase rapakivi granite intrusions in which the most evolved phase is topaz-bearing granite. The Artjärvi stock is composed of porphyritic and even-grained biotite granite and even-grained topaz granite, and the Sääskjärvi stock comprises even-grained biotite granite and porphyritic topazgranite. The granites are metaluminous to peraluminous A-type granites, showing within-plate (WPG geochemical characteristics. The topaz granites from the Artjärvi and Sääskjärvi stocks are petrographically and geochemically similar to other topaz-bearing rapakivi granites in Finland. The anomalous geochemistry of the topaz granite is essentially magmatic; postmagmatic reactions have only slightly modified its composition. Greisen veins, some of which are mineralized, are widely found associated with the Artjärvi and Sääskjärvi stocks.The most characteristic feature of the Artjärvi granite stock is a stockscheider at the roof contact of the topaz granite. The stockscheider is composed of schlieren layering and pegmatite layers parallel to the contact. The most probable mechanism for the formation of the schlieren layering is velocity-gradient sorting parallel to the flow, which led to accumulation of mafic minerals along the upper contact of the topaz granite. Cooling and contraction of the topaz granite formed fractures parallel to the roof contact and the residual pegmatite magmas were injected along the fractures forming pegmatite layers. Textures like graphic intergrowths, aplitic groundmass and fan-shaped alkali feldspar crystals associated with the Artjärvi porphyritic biotite granite and pegmatite indicatecrystallization from undercooled magma. Miarolitic cavities found in the porphyritic biotite granite and topaz granite indicate at least local volatile saturation.

  17. Pórfiro granítico Mojotoro (Salta): ¿Una cúpula intrusiva o un dique en el ciclo pampeano? / The Mojotoro granitic porphyry (Salta): An intrusive roaf or a dike in the Pampean Cycle?

    Scientific Electronic Library Online (English)

    A.J., Toselli; R.N., Alonso.

    2005-06-01

    Full Text Available El pórfiro granítico Mojotoro, constituye la cúpula de un plutón epizonal, emplazado en un área geológica bien conocida, de la Formación Puncoviscana, en las inmediaciones de la ciudad de Salta (24º47´44,9"S - 65º21´35,9"W, 1.304 m s.n.m.). Sin bien se carece de determinaciones geocronológicas, los [...] caracteres geológicos regionales y situación estratigráfica de no alcanzar los niveles del Grupo Mesón, sugieren edades pampeanas, correspondientes a la orogenia tilcárica. Los caracteres petrográficos corresponden a pórfiros graníticos, con fenocristales de feldespato potásico, acompañados por cuarzo, plagioclasa y biotita. Las rocas han sufrido intensa sericitización, caolinización y limonitización. Asimismo muestra esferulitas recristalizadas, inclusiones fluidas y fragmentos de granófiro, que indican emplazamiento somero, con rápido intercrecimiento conjunto de cuarzo en una masa de feldespato alcalino hipersolvus. La susceptibilidad magnética es baja con valores de 0,11 x 10-3 SI, típicos para granitos corticales formados a partir de protolitos metasedimentarios. Abstract in english The Mojotoro porphyritic granite is located close to the city of Salta (24°47´44,9"S - 65°21´35,9"W, 1304 m.a.s.l.), at Cerro Mojotoro in the Eastern Cordillera. The pluton is emplaced in the Puncoviscana Formation (Late Precambrian-Early Cambrian), a lithological unit composed mainly of greenish pe [...] lites. The Puncoviscana Formation is covered unconformably by Cambrian quartzites of the Meson Group. Stratigraphic relationships of the granite indicate a Pampean age and emplacement during the Tilcaric orogenic phase. Petrographically it is a porphyritic granite with K-feldspar phenocrysts accompanied by quartz, plagioclase and biotite. The rock is strongly altered by sericitization, kaolinization, and limonitization. Likewise, the granite exhibits recrystalized spherules, fluid inclusions and granophyric fragments, indicative of shallow emplacement, with fast intergrowth of quartz in a mass of K-feldspar hypersolvus. Low magnetic susceptibility, with values of 0.11x10-3 SI, is typical of cortical granite that was formed from a metasedimentary protolith.

  18. EXPLOITATION OF GRANITE BOULDER

    Directory of Open Access Journals (Sweden)

    Ivan Cotman

    1994-12-01

    Full Text Available The processes of forming, petrography, features, properties and exploitation of granite boulders are described. The directional drilling and black powder blasting is the succesful method in exploitation of granite boulders (boulder technology.

  19. The Layos Granite, Hercynian Complex of Toledo (Spain): an example of parautochthonous restite-rich granite in a granulitic area

    OpenAIRE

    Barbero González, Luis C.; Villaseca González, Carlos

    1992-01-01

    The Layos Granite forms elongated massifs within the Toledo Complex of central Spain. It is late-tectonic with respect to the F2 regional phase and simultaneous with the metamorphic peak of the region, which reached a maximum temperature of 800-850°C and pressures of 400-600 MPa. Field studies indicate that this intrusion belongs to the "regional migmatite terrane granite" type. This granite is typically interJayered with sill-like veins and elongated bodies of cordierite/ gar...

  20. U-Pb zircon ages of members of the Salem Granatic Suite along the northern edge of the Central Damaran Granite Belt

    International Nuclear Information System (INIS)

    Porphyric Salem Suite granite rocks in the low-grade Northern Zone and adjoining portion of the high-grade Central Zone give respective ages of 589+- 40 and 546+- 30 m.y. (2 omnicron) which are indistinguishable within the limit of uncertainty. A complex, diachronous tectonic history is evident. Ages of deformation and granite intrusion in the Northern Zone and the coastal region of the Huab and Ugab Rivers appear to be similar. Deposition of the Mulden Group, the single intense phase of deformation and the low-grade metamorphism of the Northern Zone were completed between 550 and 600 m.y. ago and prior to the first granite intrusions. This was between 54 and 140 m.y. before completion of deformation in the adjoining, fundamentally different, high-grade, tectonically complex, granite-rich Central Zone. D1 in the southern Central Zone is older than 595 m.y. D2 may have been coeval in both the Northern and Central Zones, but a northward decrease in age across the Central Zone cannot be ruled out. D3 decreases in age northwards across the Central Zone and is at least 20 m.y. and may be as much as 120 m.y. younger in the north. The peak of metamorphism could have been coeval in the Northern and Central Zones. D3 in the northern Central Zone (479+- 16 m.y.) is the youngest major deformation event in the orogen. The Central Zone was finally thrust against and over the Northern Zone subsequent to D3 in the formerent to D3 in the former

  1. 2005 dossier: granite

    International Nuclear Information System (INIS)

    This document makes a status of the researches carried out by the French national agency of radioactive wastes (ANDRA) about the geologic disposal of high-level and long-lived radioactive wastes in granite formations. Content: 1 - advantage of granitic formations for the geologic disposal; 2 - containers; 3 - design study of a disposal facility in granitic environment; 4 - understanding and modelling of granite; 5 - description of disposal concepts in granitic environment; 6 - long-term and safety aspects; 7 - conclusion. (J.S.)

  2. The Younger Dryas Event

    Science.gov (United States)

    This topic in depth deals with the Younger Dryas event, a short period of extremely cold temperatures interrupting the current interglacial period. It is currently debated whether the Younger Dryas event occurred solely in parts of the North hemisphere or throughout the world.The first website, (1), created by World History, provides a short, concise summary of the Younger Dryas period. Users can find a brief statement about the prevailing theory of the cause of this event. Lund University offers an amazing image of a stratigraphic record illustrating the Late Glacial sequence at the second website (2). Users can view the impressive Younger Dryas sedimentation layer and also see an image of the flower, _Dryas octopetala_, which the event is named after. Next, the Department of Natural Resources for the Province of Nova Scotia supplies images of the geologic landscape of Nova Scotia (3). Students can find descriptions of the Younger Dryas event and other glacial features. The forth website (4 ), produced by Klaus Keller as part of his lecture materials for classes at Penn State, is an online document illustrating the abrupt changes experienced on earth during the Younger Dryas. This website discusses the theorized relationship between the North Atlantic thermohaline circulation (THC) and the event. Next, the University of Arizona discusses its research on the environmental changes in mid-North America over the last several millennia (5). Users can learn how the researchers are attempting to create the first high-resolution chronology of the transition from the Late Glacial to the Early Holocene. In the sixth website (6 ), the University of Chicago offers an online article addressing the unknowns in our current understanding of climate change. Users can learn how the abrupt climate changes in the past such as the Younger Dryas are still difficult to model. Next, David J. Graham from the University of Wales addresses the importance of examining the moraine morphology and sedimentology in order to gather more knowledge about the climatic and glacio-dynamic conditions that occurred during the Younger Dryas period (7 ). This online poster provides images, figures, and descriptions of the interpretations of the landform-sediment associations present in the upper Ennerdale. Konrad Hughen from the Woods Hole Oceanographic Institution summarizes his group's research which illustrates the effects the northern tropical regions of the Southern Hemisphere experienced during the Younger Dryas event (8). In this downloadable document, users can learn about his group's creation of high-resolution records of tropical vegetation change that demonstrate the synchronization between the climate changes in the high latitude North Atlantic region and in the tropical South America during the event. Lastly, the U.S. Global Change Research Program discusses the classification of an abrupt climate change, the rapidity of past climate change according to the paleoclimatic records, the causes of climate change, and its consequences (9). Visitors can learn about the swiftness of the Younger Dryas event and how another occurrence like this may affect our society and the natural world.

  3. Shrimp U-Pb age and Sr-Nd isotopes of the Morro do Baú mafic intrusion: implications for the evolution of the Arenópolis volcano-sedimentary sequence, Goiás Magmatic Arc

    Directory of Open Access Journals (Sweden)

    Pimentel Márcio M.

    2003-01-01

    Full Text Available The Arenópolis volcano-sedimentary sequence is located in the southern part of the Goiás Magmatic Arc and includes a ca. 900 Ma calc-alkaline arc sequence made of volcanic rocks ranging in composition from basalts to rhyolites, metamorphosed under greenschist to amphibolite facies. Small calc-alkaline gabbro to granite sub-volcanic bodies are also recognized. The Morro do Baú intrusion is the largest of these intrusions, and is made of gabbros and diorites. Zircon grains separated from one gabbro sample and analyzed by SHRIMP I yielded the mean 206Pb/238U age of 890 +/- 8 Ma, indicating that the intrusion is roughly coeval or only slightly younger than the Arenópolis volcanics. Contrary to the metavolcanics, which are juvenile, the Nd isotopic composition of the Morro do Baú gabbro indicates strong contamination with archean sialic material (T DM of 2.8 Ga and EpsilonNd(T of -9.7, represented in the area by an allochthonous sliver of archean/paleoproterozoic gneisses (Ribeirão gneiss which are the country-rocks for the gabbro/dioritic intrusion. The emplacement age of ca. 890 Ma represents a minimum age limit for the tectonic accretion of the gneiss sliver to the younger rocks of the Arenópolis sequence. The data suggest that this happened early in the evolution of the Goiás Magmatic Arc, between ca. 920 and 890 Ma.

  4. Geochemistry and Geochronology U-Pb SHRIMP of granites from Peixoto de Azevedo: Alta Floresta Gold Province

    International Nuclear Information System (INIS)

    The analysis of petrographic, geochemical and geochronological data of granites in the Peixoto de Azevedo region, Mato Grosso, Brazil, in the eastern portion of the Alta Floresta Gold Province, led to the recognition of two granitic bodies bounded by regional major faults and shear zones. In the northwestern portion a body with featured as biotite granodiorite, coarse-grained, with porphyritic to inequigranular texture, metaluminous to peraluminous, high-K calc-alkaline and magnesium character. In the southeastern portion of the area, a biotite monzogranite coarse-grained, with equigranular to porphyritic texture, slightly peraluminous, high-K calc-alkaline and dominantly of ferrous character. U- Pb dating (SHRIMP) showed that the biotite monzogranite has an age of 1869 ± 10 Ma, similar to the Matupa Intrusive Suite, while the biotite granodiorite has an age of 1781 ± 10 Ma, that is the age expected to Peixoto Granite. Both units show patterns of rare earth elements with enrichment of light over heavy and negative Eu anomaly (LaN/YbN » 7.6 to 17.31 and ratios Eu/EU? between 0.46 – 0.72 for biotite monzogranite and LaN/YbN » 7.13 to 29.09 with ratios Eu/Eu? between 0.25 - 0.40 for the biotite granodiorite). Trace elements pattern for both present negative anomalies of Ba, P, Ti and Nb indicating an evolution from mineral fractionation and subduction related sources. In this paper, it is suggested that the monzogranite Matupa was developed in mature arc tectonic environment. For the Peixoto Granite, two hypotheses are suggested: (a) it was developed in younger magmatic arc environment associated with the Colider Magmatism or (b) it was generated in extensional tectonic environment during the Columbia Super continent break up. (author)

  5. Thorite in an Apollo 12 granite fragment and age determination using the electron microprobe

    Science.gov (United States)

    Seddio, Stephen M.; Jolliff, Bradley L.; Korotev, Randy L.; Carpenter, Paul K.

    2014-06-01

    We present the first quantitative compositional analysis of thorite in a lunar sample. The sample, a granitic assemblage, also contains monazite and yttrobetafite grains, all with concentrations of U, Th, and Pb sufficiently high to determine reliably with the electron microprobe. The assemblage represents the first documented occurrence of these three minerals together and only the second reported occurrence of thorite in a lunar rock. Sample 12023,147-10 is a small, monomict rock fragment recovered from an Apollo 12 regolith sample. It comprises graphic intergrowths of K-feldspar and quartz, and plagioclase and quartz, along with minor or accessory hedenbergite, fayalite, ilmenite, zircon, yttrobetafite, thorite, monazite, and Fe metal. Thorite, ideally ThSiO4, occurs in the assemblage adjacent to quartz and plagioclase, and includes a 12% xenotime ([Y,HREE]PO4) component. From quantitative electron-probe microanalysis (EPMA) of Th, U, and Pb in thorite, assuming that all of the measured Pb is radiogenic, we calculate an age of 3.87 ± 0.03 Ga. Yttrobetafite and monazite, which contain lesser concentrations of U, Th, and Pb than the thorite, yield ages of 3.78 ± 0.06 Ga and 3.9 ± 0.3 Ga, respectively. These dates are consistent with formation of the granitic material around 3.8-3.9 Ga, possibly associated with, or after, the formation of the Imbrium basin. This age falls within a group of younger ages for granitic samples, measured mainly by ion microprobe analysis of zircon, compared to a suite of older ages, ca. 4.20-4.32 Ga, also from zircons (Meyer et al., 1996). A 3.8-3.9 Ga age may reflect an origin following the Imbrium event whereby granitic melt formed as a result of heating and melting, and was mobilized and emplaced along an Imbrium-related ring-fracture system. Silicic volcanic or exposed intrusive materials occur in several circum-Imbrium locations such as the Mairan and Gruithuisen Domes and in ejecta excavated by Aristarchus crater. Perhaps sample 12023,147-10 and some of the other granitic materials sampled at the Apollo 12 site represent rocks similar to the rocks that make up these large silicic rock occurrences.

  6. Gamma-spectrometric surveys in differentiated granites. II: the Joaquim Murtinho Granite in the Cunhaporanga Granitic Complex, Parana, SE Brazil

    International Nuclear Information System (INIS)

    Detailed mapping at the NW corner of the large Neo proterozoic Cunhaporanga Granitic Complex (CGC), Parana state, SE Brazil, redefined the Joaquim Murtinho Granite (JMG), a late intrusion in CGC with an exposed area of about 10 km2, made up mainly by evolved 'alaskites' (alkali-feldspar leuco granites). This unit is in tectonic contact with the Neoproterozoic-Eocambrian volcano-sedimentary Castro Group, to the W, and is intrusive into other less evolved granitic units of the CGC to the E. Petrographically, JMG shows mainly mesoperthite and quartz, with subordinate amounts of altered micas and some accessory phases, mainly zircon. The equi to inequigranular granites are usually deformed with cataclastic textures, are often brecciated, and may have miarolitic structures. Formation of late albite, sericite, carbonate and hematite was caused by deuteric and hydrothermal alteration. A gamma-ray spectrometric survey at 231 stations which measured total counts (TC), Ueq K%, eU ppm and eTh ppm was used to construct several direct and derived maps. Compared to neighboring units the JMG has significant anomalies, especially in the TC, %K, eTh and eU maps, although the differences are less obvious in some derived maps. These evolved granites are enriched in these three elements. Geochemical behavior of K, Th and U is used to analyse the results observed in maps. Enhanced weathering under a subtropical climate with moderate to high average temperatures and heavy rainfahigh average temperatures and heavy rainfall affects mainly feldspars and biotite, and may also destabilize most U and Th-bearing accessory phases. Th is most likely retained in restite minerals in soils, being relatively immobile, while part of U may migrate as uranyl ion in oxidizing media. K is especially affected by feldspar alteration to K-free clays (mainly kaolinite), and may be completely leached. Gamma-ray spectrometric methods are valid tools to study facies in granitic rocks, especially in those that are enriched in K, Th and U. (author)

  7. Earth's youngest exposed granite and its tectonic implications: the 10-0.8 Ma Kurobegawa Granite.

    Science.gov (United States)

    Ito, Hisatoshi; Yamada, Ryuji; Tamura, Akihiro; Arai, Shoji; Horie, Kenji; Hokada, Tomokazu

    2013-01-01

    Although the quest for Earth's oldest rock is of great importance, identifying the youngest exposed pluton on Earth is also of interest. A pluton is a body of intrusive igneous rock that crystallized from slowly cooling magma at depths of several kilometers beneath the surface of the Earth. Therefore, the youngest exposed pluton represents the most recent tectonic uplift and highest exhumation. The youngest exposed pluton reported to date is the Takidani Granodiorite (~ 1.4 Ma) in the Hida Mountain Range of central Japan. Using LA-ICP-MS and SHRIMP U-Pb zircon dating methods, this study demonstrates that the Kurobegawa Granite, also situated in the Hida Mountain Range, is as young as ~ 0.8 Ma. In addition, data indicate multiple intrusion episodes in this pluton since 10 Ma with a ~ 2-million-year period of quiescence; hence, a future intrusion event is likely within 1 million years. PMID:23419636

  8. Earth's youngest exposed granite and its tectonic implications: the 10–0.8 Ma Kurobegawa Granite

    Science.gov (United States)

    Ito, Hisatoshi; Yamada, Ryuji; Tamura, Akihiro; Arai, Shoji; Horie, Kenji; Hokada, Tomokazu

    2013-01-01

    Although the quest for Earth's oldest rock is of great importance, identifying the youngest exposed pluton on Earth is also of interest. A pluton is a body of intrusive igneous rock that crystallized from slowly cooling magma at depths of several kilometers beneath the surface of the Earth. Therefore, the youngest exposed pluton represents the most recent tectonic uplift and highest exhumation. The youngest exposed pluton reported to date is the Takidani Granodiorite (~ 1.4 Ma) in the Hida Mountain Range of central Japan. Using LA-ICP-MS and SHRIMP U-Pb zircon dating methods, this study demonstrates that the Kurobegawa Granite, also situated in the Hida Mountain Range, is as young as ~ 0.8 Ma. In addition, data indicate multiple intrusion episodes in this pluton since 10 Ma with a ~ 2-million-year period of quiescence; hence, a future intrusion event is likely within 1 million years. PMID:23419636

  9. Geology and Rb-Sr geochronology of mineralised and radioactive granites and alaskites, Namibia

    International Nuclear Information System (INIS)

    The geology and Rb-Sr geochronology of four mineralised and radiometrically anomalous granites and alaskites have been studied in an attempt to establish their characteristic isotopic features. A four-fold classification of the Damaran intrusives from the central belt of the orogen into syn- to post-tectonic Salem-type granites and red granites, and late to post-tectonic leucogranites and alaskites is proposed. Whole-rock Rb-Sr ages are presented for the mineralised Ida Dome alaskite, a mineralised red granite on the farm Otjua 37, and the radioactive Salem granite and leucogranite on Stinkbank 62. The most important isotopic feature which appears to characterise the mineralised granites and alaskites is a high initial Sr-isotope ratio, and this ratio seems to increase with both time and uranium content

  10. Metallogenic aspects of Itu intrusive suite

    International Nuclear Information System (INIS)

    The integrated use of geological, geochemical, geophysical and remote sensing data is providing interesting new information on the metallogenic characteristics of the Itu Intrusive Suite. During World War II, up to 1959, a wolframite deposit was mined near the border of the northernmost body (Itupeva Granite). This deposit is formed by greisen veins associated with cassiterite and topaz, clearly linked with later phases of magmatic differentiation. Generally those veins are related to hydrothermal alteration of the granites and the above mentioned shear zone. U, Th and K determinations by field and laboratory gammaspectrometry were used for regional distribution analysis of those elements and its ratios and calculation of radioactivity heat production. In this aspects, the Itupeva Granite is the hottest and presents several anomalies in the Th/U ratio, indicative of late or post magmatic oxidation processes. (author)

  11. The Neoproterozoic layered mafic-ultramafic intrusion of Gabal Imleih, south Sinai, Egypt: Implications of post-collisional magmatism in the north Arabian-Nubian Shield

    Science.gov (United States)

    Azer, M. K.; El-Gharbawy, R. I.

    2011-06-01

    The Imleih layered mafic-ultramafic body is a Neoproterozoic intrusion covering about 45 km 2 in southern Sinai. The field relations as well as the fine grained chilled margins indicate that the layered intrusion is younger than the surrounding calc-alkaline syn-tectonic granodiorite and Iqna Shar ,a volcanics and older than the post-tectonic Iqna granite. There is a general consensus that there are no ophiolitic rocks younger than the syn-tectonic granitoids in the Arabian-Nubian Shield (ANS), which supports the non-ophiolitic origin of the Imleih layered intrusion. The studied layered intrusion is tilted to the north, with lower layers (peridotite and pyroxenite) exposed to the south and upper layers (cumulus gabbro and anorthosite) exposed to the north. Imleih rocks are cumulates, dominated by cumulus gabbro with subsequent amounts of peridotite, pyroxenite and anorthosite. Pegmatitic gabbro is locally observed. These rocks are unmetamorphosed. In the peridotite, the Fo content of olivine ranges from 0.81 to 0.83. Clinopyroxenes of the studied rocks range in composition from diopside to augite and have subalkaline affinities. Plagioclase in the cumulus gabbro is mostly bytownite (An 73-82). Two types of spinel are observed, chromite and pleonaste. Chromite has Cr# (Cr/(Cr + Al) of 0.60-0.81 whereas pleonaste have Cr# lower than 0.02. The present study revealed that the mafic-ultramafic complex of Gabal Imleih fractionated from a single batch of high Al-basaltic magma and evolved by fractional crystallization at the base of a Neoproterozoic magma chamber. Olivine and chromite were the first crystallized phases followed by pyroxene and plagioclase. Amphibole appears at nearly the same time as plagioclase. The Imleih mafic-ultramafic body was emplaced post-tectonically in a transitional phase between the calc-alkaline and alkaline magmatism.

  12. Petrochemical and Sr-Nd isotope investigations of Cretaceous intrusive rocks and their enclaves in the Togouchi-Yoshiwa district, northwest Hiroshima prefecture, SW Japan

    International Nuclear Information System (INIS)

    Petrographic, petrochemical and Sr-Nd isotopic data are presented for granitoids and microdioritic enclaves from two Cretaceous stocks (Togouchi granodiorite and Tateiwayama granite porphyry) from the Togouchi-Yoshiwa district, northwest Hiroshima prefecture, SW Japan. The data are used to examine the genetic relationships between the microdioritic enclaves and their granitoid hosts. The granodiorite, granite porphyry and the microdioritic enclaves are all calc-alkaline in nature, and belong to the I-type ilmenite series. The Togouchi graniodiorite has a Rb-Sr whole rock isochron age of 85.6±4.7 Ma with an initial Sr isotope ratio (SrI) of 0.70634±0.00012 (2?). The Tateiwayama granite porphyry has a slightly younger Rb-Sr whole isochron age (77.4±3.1 Ma) but similar SrI of 0.70653±0.00015, suggesting that both stocks may have been derived from the same source. Despite diverse whole rock chemistry, the microdioritic enclaves in the respective intrusives have quite similar initial Sr and Nd isotope ratios, suggesting that they formed by fractional crystallization of a single magma, and also that the source of the enclaves in both intrusives had similar geochemical characteristics. In both stocks, however, the enclaves have distinctly lower initial Sr isotope ratios than their respective host rocks, indicating that they were derived from a different source than their hosts. In view of the geochemical and Sr-Nd isotope data, we infer that the enclave magmas were derifer that the enclave magmas were derived from a similar LILE- and LREE-enriched source to that of the Cretaceous basalts and gabbroic-dioritic rocks that are sporadically distributed in SW Japan. Such mafic to intermediate magmas were probably derived from the upper mantle, and transferred both heat and material to the lower crust, thus producing granitic magmas by partial melting. Successive mafic magmas or their differentiates could then have been injected into the granitic magma chamber, trapped and quenched, resulting in the formation of microdioritic enclaves in both granitic stocks. (author)

  13. Mineral Chemistry and Magmatic Differentiation Evidences in the Neshveh Intrusion (NW Saveh, Central Iran)

    OpenAIRE

    Reza Keshavarzi; Dariush Esmaili; Mehdi Rezaei Kahkhaei; Mir Ali Asghar Mokhtari; Mehdi Kordlou

    2014-01-01

    Neshveh intrusion which is located in the NW of Saveh City is a part of Sahand-Bazman magmatic arc within the Central Iranian zone. This intrusion consists of quartz-monzogabbro, quartz-monzodiorite, granodiorite and granite that have intruded into the Eocene volcano-sedimentary rocks. This intrusion is medium to high-K calc alkaline, metaluminous, and I-type granitoid. All phases of the Neshveh granitoid are characterized by LREE-rich patterns with high LREE/HREE ratio...

  14. Chemical characteristics of zircon from A-type granites and comparison to zircon of S-type granites

    Science.gov (United States)

    Breiter, Karel; Lamarão, Claudio Nery; Borges, Régis Munhoz Krás; Dall'Agnol, Roberto

    2014-04-01

    The trace element content in zircons from A-type granites and rhyolites was investigated by using back-scattered electron images and electron microprobe analyses. The studied Proterozoic (Wiborg batholith, Finland and Pará, Amazonas and Goiás states, Brazil) and Variscan (Krušné Hory/Erzgebirge, Czech Republic and Germany) plutons cover a wide range of rocks, from large rapakivi-textured geochemically primitive plutons to small intrusions of F-, Li-, Sn-, Nb-, Ta-, and U-enriched rare-metal granites. While zircon is one of the first crystallized minerals in less fractionated metaluminous and peraluminous granites, it is a late-crystallized phase in peralkaline granites and in evolved granites that may crystallize during the whole process of magma solidification. The early crystals are included in mica, quartz, and feldspar; the late grains are included in fluorite or cryolite or are interstitial. The zircon in hornblende-biotite and biotite granites from the non-mineralized plutons is poor in minor and trace elements; the zircon in moderately fractionated granite varieties is slightly enriched in Hf, Th, U, Y, and HREEs; whereas the zircon in highly fractionated ore-bearing granites may be strongly enriched in Hf (up to 10 wt.% HfO2), Th (up to 10 wt.% ThO2), U (up to 10 wt.% UO2), Y (up to 12 wt.% Y2O3), Sc (up to 3 wt.% Sc2O3), Nb (up to 5 wt.% Nb2O5), Ta (up to 1 wt.% Ta2O5), W (up to 3 wt.% WO3), F (up to 2.5 wt.% F), P (up to 11 wt.% P2O5), and As (up to 1 wt.% As2O5). Metamictized zircons may also be enriched in Bi, Ca, Fe, and Al. The increase in the Hf content coupled with the decrease in the Zr/Hf value in zircon is one of the most reliable indicators of granitic magma evolution. In the zircon of A-type granites, the Zr/Hf value decreases from 41-67 (porphyritic granite) to 16-19 (equigranular granite) in the Kymi stock, Finland, and from 49-52 (biotite granite) to 18-36 (leucogranite) in the Pedra Branca pluton, Brazil. In the in situ strongly fractionated Cínovec cupola (Erzgebirge), the Zr/Hf value decreases from 33-51 in the protolithionite granite at a depth of 1255 m to 7.5-25 in the zinnwaldite granite at a depth of 40 m. At the scale of individual crystals, the Zr/Hf value decreases from 86 to 68 from the cores to the rims of the zircons from the Teplice rhyolite and from 64 to 33 in the zircons from the biotite granite at Krupka, Erzgebirge. The contents of Hf and U in zircon are dependent mainly on the degree of granite fractionation and the nature and volume of the volatile phases and are independent of the A- or S-character of the parental melt. The zircon Zr/Hf ratios 55 and 25 are proposed to approximately distinguish common, moderately evolved and highly evolved granites. Zircons from the moderately and highly evolved granites of A- and S-type can be discriminated on the basis of their HREE content and the U/Th ratios. Nb, Ta, and W are present in zircon from the highly evolved granites from all studied areas, while high As, Bi, and Sc contents are typical only for the Erzgebirge.

  15. Hydrogen isotope ratios of biotite and hornblende from some granitic masses in the Abukuma Plateau, Japan

    International Nuclear Information System (INIS)

    D/H ratios and X sub(Fe)(Fe/(Fe + Mg)) values of coexisting biotite and hornblende from ''older'' and ''younger'' granitic rocks in the northern Abukuma Plateau were measured. These data show that both granitic rocks are the typical equilibrium type of Kuroda et al. (1978). However, delta D is higher and X sub(Fe) is lower for ''older'' granitic rocks than for ''younger'' granitic rocks. This difference may depend on the silica content of the whole rocks; e.g., that of ''older'' rocks is lower than that of ''younger'' ones. delta D value of ''aqueous fluid'' in the magma of these rocks can be estimated to be -3.0 -- -3.4%, which is the same to that for the Cretaceous granitic rocks in the Kitakami mountainous district. Hornblende in the gabbroic rocks associated with these granitic rocks was also investigated and it can be considered that the hornblendes were equilibrated with the water of ''aqueous fluid'' of the granitic magma. On the other hand, the biotite-hornblende pairs from the Samegawa, Ishikawa and Miyamoto masses do not show the simple equilibrium type but the disequilibrium or complicated type. This may be related to older ages (Paleozoic time) and poly-cyclic activities in terms of hydrogen isotope exchange equilibrium in these masses. (author)

  16. Geochemical geochronology and genesis of granite from Coronel Murta, Northeast of Minas Gerais, Brazil

    International Nuclear Information System (INIS)

    Geological, petrographic, geochemical (including rare-earth elements) and geochronological data of the Coronel Murta (Northeast Minas Gerais State) post-tectonic intrusive alkalic granites were summarized in order to discuss their genesis. This paper shows that Coronel Murta granites were generated by anatexis of dominantly metasedimentary rocks, in an ensialic environment, as the late results of an intraplate A-type subduction during the Brazilian Cycle. (author)

  17. U-Pb LA-MC-ICPMS geochronology of Cambro-Ordovician post-collisional granites of the Ribeira belt, southeast Brazil: Terminal Brasiliano magmatism in central Gondwana supercontinent

    Science.gov (United States)

    Valeriano, Claudio de Morisson; Tupinambá, Miguel; Simonetti, Antonio; Heilbron, Monica; de Almeida, Julio Cesar Horta; do Eirado, Luiz Guilherme

    2011-12-01

    New U-Pb ages for zircon and titanite obtained by LA-MC-ICPMS are reported for post-collisional granites from the central Ribeira belt (Rio de Janeiro State, southeast Brazil). These post-collisional, I-type, megaporphyritic and equigranular leucogranite plutons and dykes intrude high-grade metasedimentary units, orthogneisses, and migmatites within the root zone of the deeply eroded Neoproterozoic-Cambrian Ribeira belt. The ages obtained are: 511.2 ± 6.9 Ma (zircon) for the Suruí Granite; 490.3 ± 8.7 Ma (zircon) for a cross-cutting dyke of the pegmatitic facies of the Andorinha Granite from the same outcrop; 480.7 ± 6.1 Ma (zircon) for the Frades Granite; 488.7 ± 4.2 Ma (titanite) for the Nova Friburgo Granite; and 490.9 ± 9.8 Ma (zircon) for the Sana Granite. These new U-Pb ages and those compiled from the literature for post-orogenic intrusions distributed ˜400 km along the strike of the orogen (Rio de Janeiro and Espírito Santo States), define two separate intervals for magmatic activity, which are consistent with mineralogical and structural signatures. The magmatic intervals consist of an older Cambrian magmatic pulse occurred at ca.512 Ma (Pedra Branca, Suruí and Buarama plutons), and a younger Ordovician event at ca. 486 Ma (Mangaratiba, Favela, Andorinha, Frades, Nova Friburgo and Sana granites). The Cambrian pulse post-dates the end of the first and main collisional phase by ca. 35 m.y. It also post-dates the onset of the second collisional episode by ca. 20 m.y. The late-Ordovician magmatic pulse post-dates the end of the second collisional episode by ca. 25 m.y. In map view, the alignment of the post-collisional plutons and stocks depicts a sinuous belt running along the eroded roots of central/northern Ribeira and Araçuaí belts. This granite belt probably marks the zone where preferential heating and melting of lower continental crust took place, either caused by breaking off of subducted slab, or by the extensional collapse of hot, overthickened continental crust.

  18. Note on U-Pb zircon ages from granitic rocks occurring near Prieskapoort, North-West Cape

    International Nuclear Information System (INIS)

    Two U-Pb zircon ages from granitic rocks near Prieskapoort are discussed. Evidence is presented suggesting the occurence of two different granitic rock types, hitherto regarded as being of the same age. A minimun age of 2 600 m.y. for the 'Steenkoppie' granite was obtained. Evidence, in the form of restites of Marydale Group rocks, confirms the intrusive character of the second granitic rock type, herein referred to as 'migmatite'. This 'migmatite' yielded an age of 1 170 m.y. It is suggested that the 'migmatite' represents the initial phase of the Namaqualand deformation period

  19. Tectonic significance of dikes of Westerly Granite, southeastern Connecticut and southwestern Rhode Island

    Science.gov (United States)

    Goldsmith, R.

    1988-01-01

    Undeformed Early Permian Westerly Granite dikes cut gneisses of the southeastern New England Avalon zone along coastal southeastern Connecticut and adjacent Rhode Island. Most dikes dip southward at a low angle. The Westerly dikes were emplaced in relatively warm rock penecontemporaneously with the Narragansett Pier Granite during a narrow time interval shortly after cessation of pervasive Alleghanian ductile deformation but probably before final localized movement on major shear zones. The gentle dips indicate subhorizontal release at the end stage of the Alleghanian compressive event. Doming, intrusion of granite, and subsequent rapid uplift and cooling are attributed to the underplating of Avalonian crust by an African plate during the Alleghanian. -Author

  20. Petrogenesis of magmatic albite granites associated to cogenetic A-type granites: Na-rich residual melt extraction from a partially crystallized A-type granite mush

    Science.gov (United States)

    Barboni, Mélanie; Bussy, François

    2013-09-01

    The uncommon association of cogenetic and nearly contemporaneous potassic K-feldspar A-type granites and sodic albite granites is observed within the 347 Ma-old bimodal Saint-Jean-du-Doigt (SJDD) intrusion, Brittany, France. A-type granites outcrop as small bodies (mafic layers. They emplaced early within the thermally “cool” part of the SJDD pluton directly beneath the Precambrian host rock, forming the pluton roof. Albite granites are fine-grained hololeucocratic yellowish rocks emplaced slightly after the A-type granites in the thermally mature part of the pluton. They form meter-thick sills that mingle with adjacent mafic layers and represent ca. 1 vol.% of the outcropping part of the pluton. The two granite types are similar in many respects with comparable Sr-Nd-Hf isotope compositions (87Sr/86Sr347 = 0.7071 for A-type granites vs. 0.7073 for albite granites; ?Nd347 = + 0.2 vs. + 0.3; ?Hf347zircon = + 2.47 vs. + 2.71, respectively) and SiO2 contents (74.8 vs. 74.4 wt.%). On the other hand, they have contrasting concentrations in K2O (5.30 vs. 1.97 wt.%), Na2O (2.95 vs. 4.73 wt.%) and CaO (0.48 vs. 2.04, respectively) as well as in some trace elements like Sr (59 vs. 158 ppm in average), Rb (87 vs. 35 ppm), Cr (170 vs. 35 ppm) and Ga (30 vs. 20 ppm). The isotopic composition of the A-type and albite granites is very distinct from that of the associated and volumetrically dominant mafic rocks (i.e. 87Sr/86Sr347 = 0.7042; ?Nd347 = + 5.07; ?Hf347zircon = + 8.11), excluding a direct derivation of the felsic rocks through fractional crystallization from the basaltic magma. On the other hand, small volumes of hybrid, enclave-bearing granodiorite within the SJDD lopolith suggest mixing processes within a reservoir located at deeper crustal levels. A-type granites may therefore form by magma mixing between the mafic magma and crustal melts. Alternatively, they might derive from the pure melting of an immature biotite-bearing quartz-feldspathic crustal protolith induced by early mafic injections at low crustal levels. Strong field evidences coupled to mineral chemistry and elemental geochemistry strongly support a magmatic origin for the albite granite. Sr, Nd, Hf zircon isotope data, U-Pb zircon ages, as well as data on petrography, mineral chemistry and elemental geochemistry attest that A-type and albite granites are closely related. Our preferred petrogenetic model is to consider the albite granite magma as a compositionally extreme melt that was extracted from a partially crystallized A-type granite mush at a late stage of crystallization. Alternatively, albite granites could form by melting of plagioclase-rich layers formed during A-type granite differentiation.

  1. SHRIMP zircon U-Pb dating of the mafic and felsic intrusive rocks of the Saza area in the Lupa goldfields, southwestern Tanzania: Implication for gold mineralization

    Directory of Open Access Journals (Sweden)

    Shukrani Manya

    2012-09-01

    Full Text Available The Lupa Goldfield (LGF is one of the eight structural terranes in the NW – SE striking Ubendian Belt of SW Tanzania. The LGF is comprised of granitic gneisses with bands of amphibolites which are intruded by mafic intrusions including gabbros, granodiorites, diorites; and various granites as well as metavol-canics. These rocks are cross-cut by narrow mafic dykes and aplites. SHRIMP zircon U-Pb data are presented for the granodiorite and a mafic dyke that cross-cut the granodiorites in the Saza area of the LGF, with the aim of constraining the mafic and felsic magmatism and their implication to gold mineralization. The zircon U-Pb data shows that the Saza granodiorites were emplaced at 1924 ± 13 Ma (MSWD = 2.6 whereas the cross-cutting mafic dyke yielded a zircon U-Pb age of 1758 ± 33 Ma (MSWD = 0.88. The dated granodiorite sample was in sheared contact with an altered mafic intrusive rock, most likely a diorite, along which an auriferous quartz vein occurs. The 1924 ± 13 Ma age of granodiorites is within error of the reported molybdenite Re-Os age of 1937 Ma determined for the gold mineralization event in Lupa Goldfields. Although auriferous quartz veins are younger than the granodiorites, the more or less similar ages between the emplacement of granodiorites and the mineralizing event indicate that the granodiorites might be the heat source (or driver of hydrothermal fluids responsible for gold mineralization in the Lupa goldfields. This would further suggest that gold mineralization in the LGF is intrusion-related type. The mafic dykes represent the youngest rocks to have been emplaced in the area and hence the 1758 ± 33 Ma age of the mafic dykes conclude the magmatic evolution in the Lupa goldfields during the Palaeoproterozoic.

  2. Uranium and selected trace elements in granites from the Caledonides of East Greenland

    International Nuclear Information System (INIS)

    The Caledonian fold belt of East Greenland contains calc-alkaline granite (sensu lato) intrusions with ages ranging from c.2000 Ma to c.350 Ma. The Proterozoic granites have low U contents and the pre-Devonian Caledonian granites contents of U corresponding to the clarke value for U in granites. Some aspects of the geochemistry of U are discussed using U-K/Rb, U-Sr, U-Zr, and U-Th diagrams. Secondary enrichment and mineralization occurs in fractured and hydrothermally altered granites and rhyolites situated in or near a major NNE fault zone. The U is associated with iron oxides or hydrocarbons. It is suggested that the source of the mineralization was Devonian acid magma, which also acted as a heat source for circulating hydrothermal fluids. (author)

  3. Metasomatism of ferroan granites in the northern Aravalli orogen, NW India: geochemical and isotopic constraints, and its metallogenic significance

    Science.gov (United States)

    Kaur, Parampreet; Chaudhri, Naveen; Hofmann, Albrecht W.; Raczek, Ingrid; Okrusch, Martin; Skora, Susanne; Koepke, Jürgen

    2014-06-01

    The late Palaeoproterozoic (1.72-1.70 Ga) ferroan granites of the Khetri complex, northern Aravalli orogen, NW India, were extensively metasomatised ~900 Ma after their emplacement, at around 850-830 Ma by low-temperature (ca. 400 °C) meteoric fluids that attained metamorphic character after exchanging oxygen with the surrounding metamorphic rocks. Albitisation is the dominant metasomatic process that was accompanied by Mg and Ca metasomatism. A two-stage metasomatic model is applicable to all the altered ferroan intrusives. The stage I is represented by a metasomatic reaction interface that developed as a result of transformation of the original microcline-oligoclase (An12-14) granite to microcline-albite (An1-3) granite, and this stage is rarely preserved. In contrast, the stage II metasomatic reaction front, where the microcline-bearing albite granite has been transformed to microcline-free albite granite, is readily recognisable in the field and present in most of the intrusives. Some of them lack an obvious reaction interface due to the presence of stage II albite granites only. When studied in isolation, these intrusives were incorrectly classified and their tectonic setting was misinterpreted. Furthermore, our results show that the mafic mineralogy of metasomatised granites has a significant impact on the characterisation of such rocks in the magmatic classification and discrimination diagrams. Nevertheless, the stage I metasomatised granites can be appropriately characterised in these diagrams, whereas the characterisation of the stage II granites will lead to erroneous interpretations. The close spatial association of these high heat producing ferroan granites with iron oxide-copper-gold (IOCG), U and REE mineralisation in the region indicates a genetic link between the metasomatism and the mineralisation. World-class IOCG, U and REE deposits are associated with metasomatised ferroan granites, suggesting that such a relationship may act as a critical first-order exploration target for undiscovered mineral deposits.

  4. Granite-ore deposit relationships in Central Brazil

    Science.gov (United States)

    Botelho, Nilson F.; Moura, Márcia A.

    1998-09-01

    Ore deposits related to granitic rocks in Central Brazil are associated with different Paleo- to Mesoproterozoic granite types. Sn and Au are the economic ore elements with important indium concentrations in some tin deposits. Tin mineralization is related to an A-type granite province, in the State of Goiás, composed of two distinct granite groups of 1.77 Ga and 1.58 Ga ages. The most important tin deposits are closely related to the younger group, hosted in or near to Li-mica±topaz leucogranites. Despite the chemical differences, both groups are enriched in F, Sn, Rb, Y, Th, Nb, Ga and REE. Their Nb/Ta>1 and their high F/Li ratios allow their classification as a NYF fertile granite association. Recent studies reveal indium concentrations that might be recoverable as by-product of tin. Besides indium minerals and In-bearing phases, cassiterite is the most important indium carrier (0.2-0.4% In). Primary gold mineralization is hosted in oxidized I-type calc-alkaline plutons in the northern Mato Grosso State, with characteristics either of volcanic arc or post-collisional granites. Gold occurs in small high grade vein type deposits or is disseminated in widespread hydrothermal zones with alteration such as sericitization, feldspathization and pyritization. ?34S values between +1.3 and +3.5‰ of associated sulfides are typical of magmatic deposits. The association of gold with oxidized I-type granites and the style of hydrothermal alteration are analogous to those associations present in world-class porphyry-style deposits. Although the tectono-magmagtic setting of these granites is not well understood, such an association constitutes an important target in the search for gold in the northern region of the State of Mato Grosso.

  5. PETROGRAFÍA, GEOQUÍMICA Y GEOCRONOLOGÍA DEL GRANITO DE PARGUAZA EN COLOMBIA / PETROGRAPHY, GEOCHEMISTRY AND GEOCHRONOLOGY OF PARGUAZA GRANITE IN COLOMBIA

    Scientific Electronic Library Online (English)

    Amed, Bonilla-Pérez; José Carlos, Frantz; Juliana, Charão-Marques; Thomas, Cramer; José A., Franco-Victoria; Elise, Mulocher; Zeze, Amaya-Perea.

    2013-12-01

    Full Text Available El Granito de Parguaza aflora en el departamento de Vichada-(Colombia), hacia la margen del río Orinoco y es parte del gran batolito descrito en Venezuela como Granito del Parguaza. Este cuerpo en Colombia aflora como cerros aislados tipo inselberg y serranías de poca extensión con pendientes abrupt [...] as que sobresalen entre las extensas llanuras terciarias. Representa uno de los granitos anorogénicos aflorantes más grandes del mundo y puede ser distinguido como una de las unidades colombianas más antiguas (Mesoproterozoico) que no han sufrido deformación. Se caracteriza por presentar textura rapakivi tipo wiborgita y piterlita, su composición es granítica a granítica de feldespato alcalino. Además de las variaciones composicionales y texturales, se encuentran zonas de grano fino, diques pegmatíticos, aplíticos y venas de cuarzo. Geoquímicamente se clasifica como un granito tipo A, metaluminoso a peralcalino, formado en ambiente post-colisional a anorogénico. Nuevas mediciones de U/Pb con LA-ICP-MS en circones indican nuevas edades concordantes de 1.392 ± 5 Ma y 1.402 ± 2 Ma para las partes más distales, respectivamente, mucho más jóvenes que edades propuestas anteriormente en territorio venezolano 1.545 Ma, lo cual puede ser interpretado como un intrusivo más complejo o como procesos de cristalización muy lentos de núcleo a borde. Por otro lado, estas edades son correlacionadas con granitos anorogénicos similares en el W del Cratón Amazónico en Brasil y con otros afloramientos rapakivi estudiados en el departamento de Guainía al SE de Colombia. Abstract in english The Parguaza Granite outcrops in the Vichada department of Colombia, towards the Orinoco River margin, where it conforms a portion of the large batholith described in Venezuela as Granito de El Parguaza. This intrusion outcrops in Colombia as isolated inselberg hills and moderately extended mountain [...] chains with abrupt slopes that protrude through Tertiary plains. It represents one of largest anorogenic granites worldwide and is one of the oldest colombian units (Mesoproterozoic) without tectonic deformation. The granite exhibits both typical Wiborgite and Pyterlite rapakivi texture, with a monzogranitic to alkali feldspar granitic composition. Among the compositional and textural variations, we find fine-grain zones, pegmatitic and aplitic dikes as well as quartz veins. Geochemically, it conforms a metaluminous to peralkaline A-type granite, intruded under post-collisional to rifting anorogenic conditions. New U/Pb measurements with LA-ICP-MS in zircons show hither to unknown concordant ages of 1392 ± 5 My to 1402 ± 2 My, respectively in the more distal zones; much younger than 1545 My ages reported in Venezuela, which may be explained or by a more complex intrusion and crystallization history or by a very slow crystallization process from the core to the edge; on the other hand, these ages are in concordance to similar anorogenic granites from the W Amazonian Craton in Brazil and with other rapakivi outcrops studied in the Guainía Department in the south-east of Colombia.

  6. Caracterización geoquímica del granito El Durazno, extremo norte de la sierra de Velasco, La Rioja / Geochemical characterization of El Durazno granite, Northern Sierrra de Velasco, La Rioja

    Scientific Electronic Library Online (English)

    Miguel A, Báez; Ana S, Fogliata; Steffen, Hagemann; Fernando G, Sardi.

    2012-12-01

    Full Text Available El área de estudio se ubica en el norte de la sierra de Velasco, en la provincia de La Rioja. Está compuesta principalmente por rocas graníticas que cristalizaron durante dos eventos magmáticos principales en el Ordovícico y el Carbonífero. Los granitos más antiguos presentan diferentes grados de de [...] formación y los más jóvenes no están deformados. Los granitos datados como carboníferos hasta el presente en este sector son Asha y San Blas. Este último presenta una zona central más evolucionada químicamente, asociado a mineralizaciones de Sn. El granito El Durazno aflora al sureste del granito San Blas, no está deformado e intruye al ortogneis Antinaco, compuesto por rocas deformadas del Ordovícico. Es un granito postorogénico, peraluminoso y fuertemente diferenciado, con contenidos de Na2O>K2O. Presenta altos contenidos en Rb, Li, W, Cs, Nb y Ta y bajos en Ba, Sr, Y, Zr y Ce. El índice de caracterización geoquímica (GCI) para granitos asociados a mineralizaciones de W da valores positivos mayores que 4. Las tierras raras presentan contenidos totales bajos, entre 5,3 y 15,3 ppm, anomalía negativa de Eu y efecto tetrada convexo. En el borde norte del granito El Durazno existen vetas de cuarzo con wolframita y hematita distribuidas irregularmente que intruyen al ortogneis Antinaco. Tienen rumbo aproximado N-S y una corrida irregular. La ausencia de deformación, relaciones de campo y características geoquímicas indican que el granito El Durazno es un intrusivo muy diferenciado asociado a mineralización de W y de posible edad carbonífera. Abstract in english The studied area is located in the north of the sierra de Velasco, La Rioja province. It is mainly composed of granitic rocks that crystallized during two main magmatic events in the Ordovician and Carboniferous. The older granites have different types of deformation whereas the younger granites are [...] not deformed. Two Carboniferous granites have been dated in this area: Asha and San Blas. The latter has a chemically evolved central zone related to Sn mineralization. The El Durazno undeformed granite outcrops southeast of the San Blas granite, and intrudes into the deformed Ordovician Antinaco orthogneiss. It is a postorogenic, peraluminous and strongly differentiated granite, with contents of Na2O>K2O. It has high values of Rb, Li, W, Cs, Nb and Ta, and low values of Ba, Sr, Y, Zr and Ce. The geochemical characterization index (GCI) for W-bearing differentiated granites is positive with values greater than 4. The REE show low total contents, between 5,3 and 15,3 ppm, negative Eu anomalies and a convex tetrad effect. At the northern border of the El Durazno granite, quartz veins with irregularly distributed wolframite and hematite cross-cut the Antinaco orthogneiss. The veins have irregular north-south strike. The absence of deformation, field relations and geochemical characteristics indicate that the El Durazno granite is a highly differentiated intrusive associated with W mineralization and of possible Carboniferous age.

  7. Ion Probe U-Pb dating of the Central Sakarya basement: a peri-Gondwana terrane cut by late Lower Carboniferous subduction/collision related granitic magmatism

    Science.gov (United States)

    Ayda Ustaömer, P.; Ustaömer, Timur; Robertson, Alastair. H. F.

    2010-05-01

    Our aim here is to better understand the age and tectonic history of crystalline basement units in the Sakarya Zone of N Turkey, north of the Neotethyan ?zmir-Ankara-Erzincan Suture Zone, utilising field, petrographic and ion probe dating, the latter carried out at the University of Edinburgh. One of the largest basement units, Central Sakarya, is dominated by paragneisses and schists that are best exposed between Bilecik and Sar?cakaya, forming a belt ~15 km wide x 100 km long. Smaller outcrops of this basement are exposed further north, for instance in the Geyve area. High-grade metamorphic basement is unconformably overlain by Lower Jurassic-Upper Cretaceous cover sediments of the Sakarya Zone and is in tectonic contact with the Late Palaeozoic-Early Mesozoic Karakaya Complex to the south. Ion-probe U-Pb dating of 89 detrital zircons, separated from one garnet micaschist sample, range from 551 Ma (Ediacaran) to 2738 Ma (Neoarchean). 85% of the ages are > 90 % concordant. Zircon populations cluster at ~550-750 Ma (28 grains), ~950-1050 Ma (27 grains) and ~2000 Ma (5 grains), with smaller groupings at ~800 Ma and ~1850 Ma. The first, prominent population (Neoproterozoic) reflects derivation from a source area related to a Cadomian-Avalonian magmatic arc, likely to be associated with a Cadomian/NE African terrane rather than Baltica (Baltica is known to be magmatically inactive during this period), or Avalonia/Amazonia (in view of the absence of Mesoproterozoic ages in Avalonian-Amazonian terranes). The early Neoproterozoic ages (0.9-1 Ga) deviate significantly from the known age spectra of Cadomian terranes (i.e. Armorican Terrane Assemblage) and instead suggest derivation from an original part of NE Africa. The detrital zircon age spectrum of Cambrian-Ordovician sandstones deposited at the northern periphery of the Arabian-Nubian Shield (i.e. the Elat sandstone) is notably similar to that of the Sakarya basement. The Central Sakarya terrane may have rifted in the Early Palaeozoic, relatively early compared to other E Mediterranean inferred Minoan terranes (e.g. Menderes, Crete, Bitlis), and then accreted to the Eurasian margin, possibly in during Late Palaeozoic time. The Central Sakarya metamorphic basement is cut by a number of granitic intrusions (collectively termed the Sö?üt Granite or Sar?cakaya Granite), three of which were dated in this study. Pink, alkali feldspar-rich granite (Küplü granite) yielded an age of 324.3 ±1.5 Ma. Grey, blastomylonitic biotite granite (Çalt? granite) is dated at 327.2 ± 1.9 Ma. Another granitic body with biotite and amphibole (Borçak granite) yielded a significantly younger age of 319.5 ± 1.1 Ma. Thus, late Early Carboniferous granitic magmatism in the Central Sakarya terrane could have persisted for ? 8 Ma, possibly related to subduction or collision of a Central Sakarya terrane with the Eurasian margin. This work was supported by Y?ld?z Technical University Research Fund (Project No: 29.13.02.01) and a Royal Society Travel Grant.

  8. Geochemistry and Geochronology U-Pb SHRIMP of granites from Peixoto de Azevedo: Alta Floresta Gold Province; Geoquimica e geocronologia U-Pb (SHRIMP) de granitos da regiao de Peixoto de Azevedo: Provincia Aurifera Alta Floresta, MT

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Fernanda Rodrigues da; Barros, Marcia Aparecida Sant' Ana; Pierosan, Ronaldo; Pinho, Francisco Edigio Cavalcante; Tavares, Carla; Rocha, Jhonattan, E-mail: geologia.fernanda@gmail.com, E-mail: mapabarros@yahoo.com, E-mail: ronaldo.pierosan@gmail.com.br, E-mail: aguapei@yahoo.com, E-mail: carlageologia@hotmail.com, E-mail: geologojrocha@live.com [Universidade Federal de Mato Grosso (UFMT), Cuiaba, MT (Brazil). Inst. de Ciencias Exatas e da Terra; Rocha, Mara Luiza Barros Pita; Vasconcelos, Bruno Rodrigo; Dezula, Samantha Evelyn Max, E-mail: marapita1@yahoo.com.br, E-mail: brunovasc@gmail.com, E-mail: samanthadezula@gmail.com [Universidade de Brasilia (UNB), Brasilia, DF (Brazil). Programa de Pos-Graduacao em Geologia

    2014-09-15

    The analysis of petrographic, geochemical and geochronological data of granites in the Peixoto de Azevedo region, Mato Grosso, Brazil, in the eastern portion of the Alta Floresta Gold Province, led to the recognition of two granitic bodies bounded by regional major faults and shear zones. In the northwestern portion a body with featured as biotite granodiorite, coarse-grained, with porphyritic to inequigranular texture, metaluminous to peraluminous, high-K calc-alkaline and magnesium character. In the southeastern portion of the area, a biotite monzogranite coarse-grained, with equigranular to porphyritic texture, slightly peraluminous, high-K calc-alkaline and dominantly of ferrous character. U- Pb dating (SHRIMP) showed that the biotite monzogranite has an age of 1869 ± 10 Ma, similar to the Matupa Intrusive Suite, while the biotite granodiorite has an age of 1781 ± 10 Ma, that is the age expected to Peixoto Granite. Both units show patterns of rare earth elements with enrichment of light over heavy and negative Eu anomaly (La{sub N}/Yb{sub N} » 7.6 to 17.31 and ratios Eu/EU{sup ?} between 0.46 – 0.72 for biotite monzogranite and La{sub N}/Yb{sub N} » 7.13 to 29.09 with ratios Eu/Eu{sup ?} between 0.25 - 0.40 for the biotite granodiorite). Trace elements pattern for both present negative anomalies of Ba, P, Ti and Nb indicating an evolution from mineral fractionation and subduction related sources. In this paper, it is suggested that the monzogranite Matupa was developed in mature arc tectonic environment. For the Peixoto Granite, two hypotheses are suggested: (a) it was developed in younger magmatic arc environment associated with the Colider Magmatism or (b) it was generated in extensional tectonic environment during the Columbia Super continent break up. (author)

  9. Intrusion Detection Systems

    CERN Document Server

    Pietro, Roberto Di

    2008-01-01

    In our world of ever-increasing Internet connectivity, there is an on-going threat of intrusion, denial of service attacks, or countless other abuses of computer and network resources. In particular, these threats continue to persist due to the flaws of current commercial intrusion detection systems (IDSs). Intrusion Detection Systems is an edited volume by world class leaders in this field. This edited volume sheds new light on defense alert systems against computer and network intrusions. It also covers integrating intrusion alerts within security policy framework for intrusion response, rel

  10. The regional geological and structural setting of the uraniferous granitic provinces of Southern Africa

    International Nuclear Information System (INIS)

    Uranium-bearing granites, comprising both potentially economic deposits and source rocks for uranium deposits is duricrustal and sedimentary sequences, are confined chiefly to the mobile belts of Southern Africa and to the Cape granites emplaced during late Precambrian times. The direct uranium potential of the mobile belts, i.e. the Damara, Namaqua-Natal and Limpopo belts, decreases with an increase in the age of associated ensialic diastrophism. This review paper is thus mainly confined to the Damara Belt, although a brief discussion of the potential of the Namaqua Belt is presented. Aspects of the Damara Belt that are discussed in detail, with particular reference to the occurrence of uraniferous granite, include regional tectonic setting, stratigraphy, structure, metamorphism and the patterns and origin of the uranium mineralization. Initial concentrations of uranium in basement and Nosib rocks have led, through ultrametamorphism and fractionation, to uraniferous granites of both economic and sub-economic grade. These granites, in turn, have acted as source of secondary mineralization in overlying superficial calcareous and gypsiferous deposits. The Damara Belt thus provides a good example of multicyclic processes of ore formation. With regard to the uraniferous granites of Namaqualand it is concluded that the porphyroblastic gneisses and late-intrusive Concordia granites, although not of direct economic interest, represent major sources of uranium for secondary superficial deposits. Smaller bodies of late-phase differentiates associated with the Concordia granitic gneiss may themselves, however, represent potentially economically viable deposits

  11. The Sao Jose do Rio Pardo mangeritic-granitic suite, south eastern Brazil

    International Nuclear Information System (INIS)

    In the Sao Jose do Rio Pardo region, Sao Paulo and Minas Gerais States, occur some intrusive, folded tabular bodies of mangerites associated with hornblende granitoids. The country rocks correspond to a complex association of gneisses and migmatites, locally with granulite facies assemblages. Both the magnerites and hornblende granitoids present a tectonic foliation with mineral flattening and stretching. Petrographically the mangeritic rocks are mainly dark green quartz mangerites with mesoperthite, plagioclase, quartz, hypersthene, clinopyroxene and variable amounts of hornblende, with zircon as conspicuous acessory. The pink hornblende granitoids are mainly granite s.s. exhibiting higher quartz and amphibole contents and lacking pyroxenes. Hololeucocratic alkali feldspar granites are locally associated to the hornblende granites. The textures of the mangerites and granites almost always show an important metamorphic overprinting, with relictic mesoperthite and pyroxene crystal into a granoblastic matrix. The magneritic-granitic suite is characterized by relatively high Fe/(Fe + Mg), K and HFS elements and low Ca contents, being comparable to typical anorogenic magneritic-granitic suites from Svcandinavia and North America. The Rb/Sr data indicate a Late Proterozoic metamorphic isotopic rehomogenization (930 Ma, Ro = 0.706). Geological evidence suggest that the intrusive age could be Middle Proterozoic, wich is reinforced by another Rb-Sr value of about 1300 Ma. (au another Rb-Sr value of about 1300 Ma. (author)

  12. Magnetic fabric and emplacement mechanisms in a co-mingled mafic and felsic magma chamber: the Espinharas granite (Borborema Province, NE Brasil)

    Science.gov (United States)

    Viegas, G.; Gouveia, F.; Archanjo, C.; Hollanda, M.

    2013-12-01

    The Espinharas granite is a co-mingled mafic and felsic magmatic complex forming part of the widespread Brasiliano plutonism that affected the Borborema Province during the Neoproterozoic. Syenogranite is mixed and mingled with diorite generating a range of aluminous shoshonitic hybrid rocks containing mafic microgranular enclaves (MME) of various shapes and orientations. Geochemical modelling shows that the pluton originated by upper-mantle magma underplating and fault-assisted intrusion of diorite, which would supply heat for partial melting of the crust and formation of syenogranite. The Espinharas granite comprises syenogranites and diorites associated with quartz-monzonites, monzodiorites and syenites mainly deformed in the magmatic state. The pluton is emplaced within Paleoproterozoic augen gneisses from the basement and is bounded by high-temperature NE-trending mylonitic shear zones at its western and eastern borders. To the south, the pluton is in contact with the E-trending high-grade transpressional Patos shear zone. Magmatic foliations can be observed throughout the syenogranite and in the felsic rocks, being defined by a SPO of feldspars and quartz. However, they appear to be absent in the diorite. The microgranular enclaves display irregular contacts with the host syenogranite and may be often aligned in agreement with the magmatic foliation; they are also randomly dispersed and disrupted by monzo- to syenogranitic veins. The Anisotropy of Magnetic Susceptibility (AMS) technique was employed in order to investigate the mechanical relationships between mingled mafic and felsic magmas, as well as their emplacement mechanisms. Susceptibilities are usually high (k > 1.3 mSI), suggesting that Ti-magnetite is the main carrier of the magnetic signal. The magnetic lineation plunges shallowly to NE, parallel to the pluton main elongation axis. Zircons from diorite and syenogranite yield U-Pb (SHRIMP) ages of ~ 620 Ma, which are attributed to the crystallization of the granite and are younger than the main metamorphic event in the Seridó Belt (~ 575 Ma). These data suggest that the magnetic fabric of the Espinharas granite records the high-temperature deformation observed in the Seridó Belt. This deformation was active during a prolonged time range (~ 100 Ma) in a hybrid magmatic chamber emplaced in the middle- to shallow continental crust. These conditions indicate that the Patos shear zone controlled the development of the magmatic- to solid-state fabric of the Espinharas granite, highlighting the contribution of strain partitioning in the mechanical mingling of magmas in the continental crust.

  13. The rapakivi granite plutons of Bodom and Obbnäs, southern Finland: petrography and geochemistry

    Directory of Open Access Journals (Sweden)

    Kosunen, P.

    1999-12-01

    Full Text Available The Obbnäs and Bodom granite plutons of southernmost Finland show the typical petrographic and geochemical features of the Proterozoic rapakivi granites in Finland and elsewhere: they cut sharply across the 1900 Ma Svecofennian metamorphic bedrock and have the geochemical characteristics of subalkaline A-type granites. The Bodom pluton is composed of porphyritic granites (hornblende-, hornblende-biotite-, and biotite-bearing varieties and an even-grained granite that probably represent two separate intrusive phases. This lithologic variation does not occur in the Obbnäs pluton, which is almost entirely composed of porphyritic hornblende-biotite granite that gradually becomes more mafic to the southwest. Three types of hybrid granitoids resulting from magma mingling and mixing occur on the southwestern tip of the Obbnäs peninsula. The Bodom granites are syenogranites, whereas the composition of the Obbnäs granite varies from syeno- to monzogranite. The main silicates of both the Bodom and Obbnäs granites are quartz, microcline, plagioclase (An1541, biotite (siderophyllite, and generally also amphibole (ferropargasite or hastingsite. Plagioclase-mantled alkali feldspar megacrysts are absent or rare. The accessory minerals are fluorite, allanite, zircon, apatite, and iron-titanium oxides; the Obbnäs granite also contains titanite. The Bodom and Obbnäs granites are metaluminous to weakly peraluminous, with average A/CNK of 1.00 and 1.05, respectively, have high Fe/Mg (average FeOtot/[FeOtot+MgO] is 0.94 for the Bodom and 0.87 for the Obbnäs granites, and high Ga/Al (3.78 to 5.22 in Bodom and 2.46 to 4.18 in Obbnäs. The REE contents are high with LREE-enriched chondrite-normalized patterns and moderate (Obbnäs to relatively strong (Bodom negative Eu-anomalies. The Obbnäs granite is enriched in CaO, TiO2, MgO, and FeO, and depleted in SiO2 and K2O compared to the Bodom granites. Also, there are differences in the Ba, Rb, and Sr contents of the two plutons (Ba and Sr higher, Rb lower in Obbnäs that cannot easily be traced to single parental granite magma. These features, together with the presence of titanite in the Obbnäs pluton, suggest different sources for the granites of the two plutons: a potassium feldspar-rich source for Bodom and potassium feldspar-poor for Obbnäs.

  14. Human intrusion: New ideas?

    International Nuclear Information System (INIS)

    Inadvertent human intrusion has been an issue for the disposal of solid radioactive waste for many years. This paper discusses proposals for an approach for evaluating the radiological significance of human intrusion as put forward by ICRP with contribution from work at IAEA. The approach focuses on the consequences of the intrusion. Protective actions could, however, include steps to reduce the probability of human intrusion as well as the consequences. (author)

  15. Study on Kalimantan uranium province: The assessment on uranium mineralization of metamorphic and granitic rocks at Schwaner mountains

    International Nuclear Information System (INIS)

    Uranium exploration activities done by CEA-BATAN had discovered uranium occurrences as the radiometric and uranium content anomalies at metamorphic and granite rocks of Schwaner Mountains, Kalimantan. A part of the occurrences on metamorphic rocks at Kalan basin has been evaluated and be developed onto follow-up step of prospecting by construction of some drilling holes and an exploration adit. In order to increase the national uranium resources, it is necessarily to extent the exploration activity to out side or nearby of Kalan basin. The goal of this assessment is to understand the uranium accumulation mechanism at Pinoh metamorphic rocks of Kalan Kalimantan and to delineate areas that uranium may exist. The assessment was based on the aspect of geology, anomaly of radioactivity and uranium contents, tectonics and alterations. Pinoh metamorphic rocks which is influenced by Sukadana granite intrusion are the high potential rocks for the uranium accumulation, because the intrusion contains a relatively high of U, Th, Cu, Zn, Nb, Mn, and W. The potential rock distributions are in between G. Ransa granite intrusion at the east and Kotabaru granite intrusions at the west. The mineralizations are categorized as vein type deposits of granitic association

  16. Late-magmatic to hydrothermal processes in the Ilímaussaq intrusion, South Greenland

    OpenAIRE

    Graser, Gesa

    2008-01-01

    The 1.16 Ga old, persodic Ilímaussaq intrusion in South Greenland solidified at a depth of about 3 to 4 km, between the granitic basement and the sandstones and pillow-bearing basalts of the Eriksfjord Formation. The intrusion consists of alkali granite, syenites, and agpaitic nepheline syenites, which are cut by late-magmatic veins. This thesis deals with late-magmatic to hydrothermal processes in the Ilímaussaq complex and focuses on the fluid phase. The late-stage fluids are of major inter...

  17. Petrogenesis and Zircon U-Pb radiometric dating in Herris granite (NW Shabestar) East Azarbaijan Province

    International Nuclear Information System (INIS)

    Heris intrusive body has cut Kahar Formation and has been covered by Permian basal sediments, non-conformably. The composition of this body is granite- alkali granite with meta luminous to weak peraluminous nature. The strong negative anomaly of Eu in REE diagram indicates the presence of plagioclase in the source area or differentiation of it during evolution of the magma. Negative anomaly of Ba and enrichment of Rb and Th relative to Ta and Nb is an indicator of crustal origin. These granites are within-plate and A-type granites, which have been formed by partial melting of tonalitic- granodioritic source in extensional setting. Zircon U-Pb dating yields 306±34 Ma for crystallization of these rocks. This age is consistent with primary extensions of rifting in Arabian- Iranian platform.

  18. Potassium-argon ages of the Amritpur granite, District Nainital, Kumaun Himalaya and its stratigraphic position

    International Nuclear Information System (INIS)

    Potassium-argon ages of muscovite and biotite, separated from the Amritpur granite, District Nainital, Kumaun Himalaya, determined in the 'Geochronology Laboratory' of the IGEM Institute of the USSR Academy of Sciences, Moscow, are 1880 +- 40 m.y. and 1330 +- 40 respectively. The granitic body apparently shows intrusive relationship with quartzite-metavolcanic association of the Bhimtal-Bhowali area of which the latter has given a whole rock K-Ar age of 228 +- 10. These reveal that the Amritpur granite is composite in nature intruded in Middle Proterozoic Period (1880 +- 40 m.y.) and later remobilised at different periods with the development of tourmaline granite in the peripheral parts, as the latest phase. (author)

  19. Contribution to the uranium geochemistry on granites in Ecuador

    International Nuclear Information System (INIS)

    This work aims to define the position of two of Ecuador granitic deposits within the field of the geochemistry of granites in general and of the geochemistry of uranium in particular. The regions concerned are: The Bonita and ABITAGUA. For each range the petrochemical framework is first of all determined and then the degree of chemical homogeneity of rocks is evaluated. In the petrochemical groups thus obtained the geochemical behaviour of the uranium is studied. From the viewpoint of the geochemistry of the granites under investigation, a comparison of the laws of distribution of the mayor elements in two ranges shows up a covergence of average composition which was not anticipated by geological and petrografic considerations alone. The statistical and geochemical distribution laws of the total uranium as a function of petrochemical variations are established. A study of chemical forms of uranium in the rocks has drawn an attention to the qualitative and quantitative importance of the faction of uranium soluble in delute acids. We have therefore reconsidered on the one hand, the laws of distribution of the insoluble and we have justified on the other hand the interest presented by the soluble post magmatic phenomena which makes possible to find a genetic connection between the uraniferous deposits and the intrusive massifs. Finally we have given tables of analytic composition total of the granites. (Author)

  20. The assessment of human intrusion into underground repositories for radioactive waste Volume 1: Main report

    International Nuclear Information System (INIS)

    This report has been prepared with the primary objective of establishing a methodology for the assessment of human intrusion into deep underground repositories for radioactive wastes. The disposal concepts considered are those studied in the performance assessment studies Pagis and Pacoma, coordinated by the CEC. These comprise four types of host rock, namely: clay, granite, salt and the sub-seabed. Following a review of previous assessments of human intrusion, a list of relevant human activities is derived. This forms the basis for detailed characterization of groundwater abstraction and of exploitation of mineral and other resources. Approaches to assessment of intrusion are reviewed and consideration is given to the estimation of probabilities for specific types of intrusion events. Calculational schemes are derived for specific intrusion events and dosimetric factors are presented. A review is also presented of the capacity for reduction of the risks associated with intrusions. Finally, conclusions from the study are presented

  1. The assessment of human intrusion into underground repositories for radioactive waste Volume 2: Appendices

    International Nuclear Information System (INIS)

    This report has been prepared with the primary objective of establishing a methodology for the assessment of human intrusion into deep underground repositories for radioactive wastes. The disposal concepts considered are those studied in the performance assessment studies Pagis and Pacoma, coordinated by the CEC. These comprise four types of host rock, namely: clay, granite, salt and the sub-seabed. Following a review of previous assessments of human intrusion, a list of relevant human activities is derived. This forms the basis for detailed characterization of groundwater abstraction and of exploitation of mineral and other resources. Approaches to assessment of intrusion are reviewed and consideration is given to the estimation of probabilities for specific types of intrusion events. Calculational schemes are derived for specific intrusion events and dosimetric factors are presented. A review is also presented of the capacity for reduction of the risks associated with intrusions. Finally, conclusions from the study are presented

  2. Identifying granite sources by SHRIMP U-Pb zircon geochronology: an application to the Lachlan foldbelt

    Science.gov (United States)

    Keay, Sue; Steele, David; Compston, William

    1999-12-01

    The potential genetic link between granites and their host sediments can be assessed using zircon age inheritance patterns. In the Lachlan fold belt, southeastern Australia, granites and associated high-grade metasedimentary rocks intrude low-grade Ordovician country rock. This relationship is well-exposed in the Tallangatta region, northeast Victoria (part of the Wagga-Omeo Metamorphic Complex). In this region granites (two I-types and two S-types) have intruded during the mid-late Silurian between approximately 410-430 Ma based on the ages of magmatic zircons. The age spectra for inherited zircons from the granites have been compared with those of detrital zircons from the enclosing low- and high-grade metasediments. In broad terms, both for detrital zircons in all four sediments and for inherited zircons in three of the four granites, the dominant ages are early Paleozoic and Late Precambrian, with sporadic older Precambrian ages extending up to 3.5 Ga. The ages of the youngest detrital zircons from the low-grade Lockhart and Talgarno terranes limit the time of sedimentation to ca. 466 Ma or younger. The youngest detrital zircons from two samples of the high-grade Gundowring terrane are 473 Ma, making these sediments Ordovician or younger, not Cambrian as originally suggested. However, the individual age spectra for the four selected metasediments are not well matched when closely examined. The age spectra of the inherited zircons in the granites also do not adequately match those in any of the metasediments. Thus, the metasediments might not be representative of the actual source rocks of the granites. While the exact source of the granites cannot be identified from the analysed samples, the existence of a large population of ca. 495 Ma inherited zircon grains in the S-type granites requires that the granite source contains a significant proportion of Cambrian or younger material. This does not preclude the existence of a Precambrian basement to the Lachlan fold belt but indicates that at the level of S-type magma generation, a Cambrian and/or younger protolith is required.

  3. Radioelemental characterization of neoproterozoic south Khasi batholith and mylliem granite pluton by portable gamma-ray spectrometry: its implication on uranium exploration in parts of east and west Khasi hills, Meghalaya

    International Nuclear Information System (INIS)

    Younger granite activity in the form of South Khasi Batholith (SKB), Kyrdem, Mylliem and Nongpoh plutons occur as intrusive into the basement gneissic complex and Paleo-Mesoproterozoic Shillong group of rocks. Ground portable gamma ray spectrometric survey carried out over the SKB, the Mylliem pluton and the basement gneissic complex. The eTh, eTh/eU and K contours clearly demarcate their lithocontacts. Radiometrically, these plutons are of hyperacidic to alkaline in nature. The magmatic evolution and the differentiated origin of granites are reflected by high concentration of eTh and K. The low Th/K values within the pluton indicate presence of diorite bodies and also suggest K enrichment along the margin of the Mylliem pluton. Higher concentration of radioelements along the margin of Mylliem pluton may be due to the role of hydrothermal phase to transport the radioelements. The high eTh/eU values and uranium favourability index of the SKB may imply possible loss of considerable amount of uranium to become provenance for the nearby uranium districts. (author)

  4. Application of Sr Isotopic Data to Tuolumne Intrusive Series, Sierra Nevada, CA

    Science.gov (United States)

    Jeff Tepper

    In this problem set students are given Rb/Sr and 87Sr/86Sr data for whole rock and mineral samples from three granitic intrusions in the Sierra Nevada. They use these data (in EXCEL) to calculate isochron ages and initial ages for the intrusions and then interpret their results. This problem is intended to teach some spreadsheet skills (linear regressions, graphing) as well as having them think about the use of radiogenic isotopes.

  5. Sr-Nd isotope geology and tectonomagmatic setting of the Dehsalm intrusives (Lut Block, Eastern Iran)

    OpenAIRE

    Arjmandzadeh, R.; Santos, J.F.; Ribeiro, S.

    2013-01-01

    The Dehsalm porphyritic shallow intrusives belong to the Lut Block volcanic-plutonic belt (central eastern Iran). Previous research on alteration, mineralization and hydrothermal fluids indicates that a Cu-Mo porphyry type mineralization system is related with these intrusives (Arjmandzadeh et al., 2012). The rocks studied in this work range in composition from gabbro-diorite to granite, with dominance of monzonites and quartz monzonites, and have geochemical features of high-K calc alkaline ...

  6. Geological characteristics of granite type uranium deposits in middle of Inner Mongolia in comparison with south China

    International Nuclear Information System (INIS)

    Granites extensively distributed in middle of Inner Mongolia and South China, namely Caledonian, Hercynian and Yanshanian. Some of the intrusive are composed of granites which belong to different ages. Some of the uranium deposits were found inside the granite bodies or in sedimentary rocks and meta sedimentary rocks along the exocontact zone. Granite rock was comparing in middle Inner Mongolia and South China, including Uranium ore-forming geological conditions. ore-forming process and Ore-controlling factors. Think the Uranium ore-forming geological conditions is similar; ore-forming process is mainly for low-mid temperature hot liquid; Uranium ore bodies (uranium mineralization) was controlled by fracture. Explain granite type uranium mineralization potential is tremendous in middle of Inner Mongolia. (author)

  7. The U-fertility criteria applied to the El Sela granite, Eastern Desert, Egypt

    International Nuclear Information System (INIS)

    El Sela area is located in the southern Eastern Desert of Egypt, between Latitudes 22 deg. 13' and 22. deg 19' N and Longitudes 36 deg. 11' and 36 deg. 15' E, about 30 km south west of Abu Ramad City. It occupies about 73.5 km2. For a long time the granite massifs have been considered as resulting from the diapiric emplacement of large magma bodies. Recent studies increasingly show that most granite plutons in fact results from successive accretion of multiple injections of highly variable sizes, not always co-genetic and with highly variable metallogenic potential. Such a conception has very important consequences in exploration because the mineralization may be genetically related only to specific magma intrusion within the large granite complex as shown in Kab Amiri granite central Eastern Desert of Egypt for episyenites and in the Saint Sylvestre granite in the French Massif Central for vein type uranium mineralization. Therefore, detailed mapping and characterization of the different granite phases is decisive to define the most fertile parts of granite plutons for the occurrence of mineralization on which the exploration has to be focused. Such a concept is particularly applicable in the granite plutons of the Eastern Desert of Egypt where outcropping conditions are excellent. The fertility of a granitic pluton is mostly related to the extent of the overlap between the magmatic uranium enrichment, hydrothermal reworking through open fracture system an reworking through open fracture system and the existence of a suitable reservoir for the leached metals and followed eventually by a supergene enrichment phase. The northern part of El Sela granite complex was identified as the most fertile part where many granite intrusions are crosscut by long and wide shear zones associated with a series of alteration processes. The studied example is the ENE-WSW shear zone located in the northern part of El Sela granite pluton. The uranium mineralizations are the result of a succession of reactions between the rocks or minerals and the fluids. Hence, we have carried out detailed geologic and tectonic mapping coupled with laboratory mineralogical and geochemical studies. Field observations has shown that Gabal El Sela granites are highly weathered, cavernous and exposed as low to moderately separated hills which forms the remnants of a circular shaped granite pluton composed of at least two main different granite intrusions. The detailed geological and tectonic studies have shown that El Sela area was affected by at least nine successive tectonic events. These events are reflected by the high fracture intensity and consequently the intense weathering of the granite. It was proposed that the complex magmatic and tectonic history of the northern part of the El Sela granitic complex is highly fertile and represent a promising target for the occurrence of uranium ore deposits which are must be tested by a drilling program to complete the geophysical subsurface studies

  8. Age and geochemistry of granites in Gejiu area, Yunnan province, SW China: Constraints on their petrogenesis and tectonic setting

    Science.gov (United States)

    Yanbo, Cheng; Jingwen, Mao

    2010-12-01

    Gejiu is one of the largest polymetallic tin ore districts in the world. Located at the westernmost end of the South China tungsten-tin province (or Nanling tungsten-tin province), it is a granite-related (Gejiu granite) magmatic-hydrothermal system. Nine samples from two phases of Gejiu granitic intrusions have been analyzed by SHRIMP and/or LA-ICPMS zircon U-Pb techniques, yielding ages ranging from 77.4 ± 2.5 Ma to 85.0 ± 0.85 Ma. Whole rock analysis shows that both phases are high-K and alkali-rich granites and their ACNK values fall mainly into a small range of 1.0-1.1. Moreover, Harker diagrams indicate that granites experienced strong fractional crystallization during magmatic evolution. Most granites display relative enrichment in LREE and strong Eu depletion. The whole rock average ? Nd( t) values of the Gejiu granites vary from - 9.3 to - 6.9, whereas a range of - 8.12 < ? Hf( t) < 1.21 is defined by magmatic zircons. Sr-Nd-Hf isotope data indicate that the granites have been mainly derived from crustal melts with minor input of mantle component. Two stage Nd and Hf model ages, together with isotopic characteristics, indicate that the Gejiu granite magmas were possibly derived from partial melting of Mesoproterozoic continental crust, with minor input of mantle-derived melts, followed by extensive fractional crystallization.

  9. The Swedish Bohus granite - a stone with a fascinating history

    Science.gov (United States)

    Schouenborg, Björn; Eliasson, Thomas

    2015-04-01

    One of the most well-known and well spread Swedish stone types used as building stones is the Bonus granite. It outcrops in an area north of Gothenburgh (SW Sweden), along the coastline, approximately 35 km wide and 85 km long. The granite continues into Norway as the Iddefjord granite. The Bohus granite is one of Sweden's youngest granites. Isotopic dating shows that the magma cooled at about 920 M years ago and thus marking the end of the Sveconorwegian orogoney. It is a composite granite massif area with several granitic intrusions but with rather homogeneous mineralogy. However, colour and texture varies quite a lot and the colour ranges from red to reddish grey although some pure grey varieties occur sparsely. The grain size ranges from medium grained to coarse grained and even with some porphyric parts. Quarrying in an industrial scale started 1842. The merchant A C Kullgren opened the first quarry and produced stones for the construction of the 86 km long Trollhättan channel connecting lake Vänern and the Atlantic ocean in the SW Sweden The stone was used for constructing harbors and wharves along the channel. Several quarries opened in the late 1800 around 1870 - 1890 and the export increased steadily with deliveries to Germany, Denmark, Holland, England and even to South America. The stone industries in Bohuslän (Bohus county), at its peak in 1929, engaged around 7 000 employees. During the depression in 1930 almost all of them became unemployed. However, as a curiosity, production and export continued to Germany for construction of Germania, the future World capital city ("Welthauptstadt Germania"), planned by Adolf Hitler and Albert Speer. About 500 stone workers were kept employed for this project during the late thirties. Today several varieties are still produced: Evja/Ävja, Tossene, Brastad, Näsinge, Broberg, Nolby, Allemarken and Skarstad. However, the number of stone workers is far from that of the early 1900. The Swedish production is mainly blocks but also paving products like sets, slabs and kerb stones are still manufactured in Sweden. Blocks are generally further processed in other countries like Italy and China to reach the European market as semi-finished products like slabs or finished products for any kind of application. The granite is very durable and suitable for all types of natural stone products.

  10. Geochemistry of pegmatites associated with the Cape Coast granite complex of southern Ghana

    International Nuclear Information System (INIS)

    The Cape Coast granite complex, which is associated with the metasedimentary basin rocks of Birimian in Ghana are, also referred to as the basin - type granitoids, and forms part of the two major types of Eburan granitoids in Ghana. The Cape Coast granite complex is characterized by various intrusions such as acid intrusion and pegmatites. The pegmatites associated with the Cape Coast granite complex are noted to be related to the margin of the granite batholiths. The mineralogical characteristics of the pegmatites have been documented, but there is little published information on the geochemical characteristics, source and tectonic settings and mode of emplacement of these pegmatites as compared to the Cape Coast granite complex. The objectives of this project were therefore to determine the compositions and geochemistry of the pegmatite and use the data to infer the possible source of these pegmatites. The geochemical data indicates that the pegmatites of the Egyaa, Saltpond and Akim Oda areas consist of a low to high-K, S-type characteristics, with three samples from Saltpond having metaluminous character. Lower values of molar CaO/ (MgO + FeOtot) coupled with higher values of molar Al2O3/ MgO + Fetot) suggest their derivation from partial melting from metabalistic source. The data suggests the rocks so have emplaced in a volcanic arc and ocean ridge geotectonic environment. (au)

  11. Petrology and geochemistry of the Los Cuartos granite, Tafi del Valle, Tucuman, northwest of Argentina: its integration to the regional magmatic layout; Petrologia y geoquimica del granito Los Cuartos, Tafi del Valle, Tucuman, noroeste de Argentina: integracion al esquema magmatico regional

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, J.P.; Bellos, L.I.

    2010-07-01

    Los Cuartos Granite crops out on the western flank of the Cumbres Calchaquies, east of Tafi del Valle, Tucuman Province, Argentina. It has a granitic to granodioritic composition, of two micas, being biotite dominant. The granite is medium grained and inequigranular, with rare K-feldspar megacrysts. It contains host-rock xenoliths with different degrees of assimilation. The granite intrusion produced contact metamorphism in the surrounding basement, with development of andalucite porphyroblasts and poikiloblastic biotite. The granite is calk-alkaline and peraluminous, and is K- and P-rich and Ca- and Napoor compared to other granitoids of the region. The pluton shows late-tectonic features with regard to the regional deformation. The granite possibly intruded during the Ordovician (Famatinian Cycle) and its emplacement was structurally controlled by the Tafi Megafracture. Los Cuartos Granite and other intrusive bodies of the region share similar petrographical, geochemical, structural and geochronological characteristics. (Author).

  12. Geology of the Northern part of the Strath Ossian Granite, Scotland

    International Nuclear Information System (INIS)

    The Strath Ossian Granite is made up of granodiorite, dark, variable 'granodiorites' interpreted as mobilised diorite or basic material, appinite and porphyritic granodiorite. Huge rafts of psammitic metasediments occur within the mass and three fracture-zones and numerous dykes, dominantly of porphyrite, cut across it in a north-easterly direction. Granite emplacement may have occurred in stages, early batches being xenolith-rich and later ones xenolith-poor. New batches were intruded centrally, which created strong radial stresses, sufficiently strong to make room for the intrusion by forcing the metasedimentary country rocks downwards and aside. (author)

  13. Interior intrusion detection systems

    International Nuclear Information System (INIS)

    The purpose of this NUREG is to present technical information that should be useful to NRC licensees in designing interior intrusion detection systems. Interior intrusion sensors are discussed according to their primary application: boundary-penetration detection, volumetric detection, and point protection. Information necessary for implementation of an effective interior intrusion detection system is presented, including principles of operation, performance characteristics and guidelines for design, procurement, installation, testing, and maintenance. A glossary of sensor data terms is included. 36 figs., 6 tabs

  14. Intrusion Detection System: Overview

    OpenAIRE

    Alanazi, Hamdan O.; Noor, Rafidah Md; Zaidan, B. B.; Zaidan, A. A.

    2010-01-01

    Network Intrusion Detection (NID) is the process of identifying network activity that can lead to the compromise of a security policy. In this paper, we will look at four intrusion detection approaches, which include ANN or Artificial Neural Network, SOM, Fuzzy Logic and SVM. ANN is one of the oldest systems that have been used for Intrusion Detection System (IDS), which presents supervised learning methods. However, in this research, we also came across SOM or Self Organizi...

  15. Uranium enriched granites in Sweden

    International Nuclear Information System (INIS)

    Granites with uranium contents higher than normal occur in a variety of geological settings in the Swedish Precambrian, and represent a variety of granite types and ages. They may have been generated by (1) the anatexis of continental crust (2) processes occurring at a much greater depth. They commonly show enrichement in F, Sn, W and/or Mo. Only in one case is an important uranium mineralization thought to be directly related to a uranium-enriched granite, while the majority of epigenetic uranium mineralizations with economic potential are related to hydrothermal processes in areas where the bedrock is regionally uranium-enhanced. (Authors)

  16. Dirty or Tidy ? Contrasting peraluminous granites in a collapsing Orogen: Examples from the French Massif Central

    Science.gov (United States)

    Villaros, Arnaud; Pichavant, Michel; Moyen, Jean-François; Cuney, Michel; Deveaud, Sarah; Gloaguen, Eric; Melleton, Jérémie

    2013-04-01

    Post collisional collapse commonly enhances crustal melting. Such melting typically produces peraluminous granitic magmas. In the French Massif Central, a mid-crustal segment of the western Variscan belt, two large granitic bodies were produced during the collapse of the Variscan Belt. The St Sylvestre Leucogranitic Complex (SSyL) in the western part of the Massif Central and the Velay Migmatitic Complex (VMC) in the Eastern part. Although these two complexes are formed in similar geodynamic context they present meaningful petrological and geochemical differences. The VMC (~305 Ma) is clearly intrusive in migmatitic terranes. The migmatitic host recorded two successive melting events M3 (720 °C and 5kb) dated between 335 and 315 Ma and M4 (850°C and 4 kb) dated at 305 Ma. The compositions of the VMC are strictly H2O-undersaturated and ranges from leucogranitic to granodioritic. Three main successive granite types have been distinguished (1) A heterogeneous banded biotite granite, (2) A main biotite-cordierite granite, where cordierite can be prismatic, as cockade or pseudomorphic (3) a late magmatic with large K-feldspar phenocryst and prismatic cordierite. The compositions of the VMC granites are quite similar to typical Australian S-type granites in the sense that they also show a positive correlation between ferromagnesian abundance and aluminosity. The SSyL (~320 Ma) is intrusive in upper greenschist facies to upper amphibolite migmatitic metasediment and orthogneiss (~3kb). The compositional variety observed in the SSyL suggests a continuous trend from a moderately mafic, peraluminous magma (cd- and sill- granite) to a H2O saturated granite ("two-mica" granite) facies and finally to an extremely felsic, H2O-saturated magma. Three granitic units have been recognized in the SSyL: (1) the western "Brame Unit" composed of the less evolved cd- and sill- granite facies (2) the central "St Sylvestre Unit", composed mainly by U-rich two-mica granite, intruded by two synchronously emplaced fine grained granites to its western margin: "Fanay" (biotite dominant) and "Sagne" (Li-muscovite only) (3) the eastern "St Goussaud Unit" mostly composed of a muscovite-dominant leucogranite surrounded by Sn-W mineralization. The compositions in the SSyL have a weak ferromagnesian character, negatively correlated with aluminosity and are quite similar in composition to High Himalayan syn-collisionnal peraluminous granite (e.g. Manaslu) Compositional trend of the VMC granite can be easily mimicked by the addition of peritectic material (i.e. produced during incongruent biotite melting) to experimental melts produced through the melting of metasediments (Dirty). Compositions of the SSyL are similar to experimental melt only (Tidy). Such differences in composition could be the results of different processes: 1) Different melting reactions as a consequence of different conditions of melting (e.g. different source composition, temperature). 2) The peritectic phases remained "trapped" in the source during melt extraction due to the structuration of the source or a lower melt viscosity (e.g. higher F, Li, H2O contents). Interestingly, while within dirty granites, peritectic phase entrainment controls compositional variability, Tidy granites display original melt compositional variability as well as the potential effects of late magmatic processes.

  17. Intrusion detection sensors

    Energy Technology Data Exchange (ETDEWEB)

    Williams, J.D.

    1978-07-01

    Intrusion detection sensors are an integral part of most physical security systems. Under the sponsorship of the U.S. Department of Energy, Office of Safeguards and Security, Sandia Laboratories has conducted a survey of available intrusion detection sensors and has tested a number of different sensors. An overview of these sensors is provided. This overview includes (1) the operating principles of each type of sensor, (2) unique sensor characteristics, (3) desired sensor improvements which must be considered in planning an intrusion detection system, and (4) the site characteristics which affect the performance of both exterior and interior sensors. Techniques which have been developed to evaluate various intrusion detection sensors are also discussed.

  18. Intrusion detection sensors

    International Nuclear Information System (INIS)

    Intrusion detection sensors are an integral part of most physical security systems. Under the sponsorship of the U.S. Department of Energy, Office of Safeguards and Security, Sandia Laboratories has conducted a survey of available intrusion detection sensors and has tested a number of different sensors. An overview of these sensors is provided. This overview includes (1) the operating principles of each type of sensor, (2) unique sensor characteristics, (3) desired sensor improvements which must be considered in planning an intrusion detection system, and (4) the site characteristics which affect the performance of both exterior and interior sensors. Techniques which have been developed to evaluate various intrusion detection sensors are also discussed

  19. Multiple-staged granite evolution and Ta?Nb mineralization in South China

    Science.gov (United States)

    Lin, Yin; Jinchu, Zhu; Shouxi, Hu

    The Mesozoic post-orogenic granites in South China are widespread. Hundreds of tungsten and tin mineral deposits are closely associated with these granites. However, the number of Ta?Nb deposits including those of the granite-type and the pegmatite-type, are relatively less. On the basis of geology, petrology, geochemistry and mineralization data from 8 ore deposits and related granites, we suggest that the Ta?Nb mineralized granites are the special products of well-evolved granite magmas. The most important W and Sn deposits are clustered in post-Caledonian uplift and adjacent Hercynian-Indosinian depression of the South China orogenic belt. Most of the Ta?Nb mineralizations are found within 20 km from the boundary faults surrounding the South Jiangxi post-Caledonian uplift. The paragenetic features of rare metal elements show that Ta?Nb are accompanied by W in the uplift region, and by Sn in the depression region. The general intrusive sequence of a rare metal-bearing granite complex is: rare metal barren (porphyrytic) biotite granite—W and/or Sn ore-forming granite—Ta?Nb (Sn) mineralized granite. The geological and geochemical data from eight mineralization districts indicate that the Ta?Nb mineralizations are always developed in the last stage of a multiple-stage granite evolution. Albite-rich granite is the most common rock type of the Ta?Nb ore-bearing granite, while the maximum albite contents in different deposits vary from more than 60% to less than 30%. Quartz with "snow ball" structure, topaz, and Li-micas (lepidolite, zinnwaldite, Li-muscovite and protolithionite) exist as common typomorphic minerals. The typical Ta?Nb host are Mn-rich columbite-Tantalite and sometimes microlite and Ta-cassiterite. The pegmatoid crust (stockscheider) can be used as one of the most distinctive indicators for the degree of rare metal-tearing granite evolution based on its thickness and zonation. Compared with the normal granites, the Ta?Nb mineralized granites have very special geochemical compositions. The Ta?Nb mineralized granites are characterized by high Na 2O, Na 2O/K 2O ratios (>1 wt%), Al 2O 3, Li and F and very low TiO 2, MnO, MgO and CaO. Most typically, nearly all the Ta?Nb mineralized granites bear very low total REE contents (less than 50 ppm), low Sr and Zr (both usually less than 30 ppm) and very high Rb (more than 700 to 3000 ppm). Geochemical features, excluding the contribution of post-magmatic alteration, change gradually from the earlier to the later phases in a granite complex, showing some trends of magmatic evolution. For example, two good negative exponential correlation curves on the Rb?Sr diagrams (or a correlogram for other elements) of Yichun ad Dengfuxian multiple-stage granite plutons indicate a fractional crystallization mechanism which might have been an effective way to enrich the rare metal elements. The granite-type Ta?Nb deposits, where Ta is economically more important than Nb, will be the only Ta?Nb mineralization type discussed in this paper.

  20. Nearly contemporaneous evolution of the A- and S-type fractionated granites in the Krušné hory/Erzgebirge Mts., Central Europe

    Science.gov (United States)

    Breiter, Karel

    2012-10-01

    The Krušné hory/Erzgebirge Mountains is one of the best-known provinces of granite magmatism and associated metallogenesis in Europe. Variscan magmatic activity in the Krušné hory/Erzgebirge area spanned the period from 330 to 295 Ma. For much of this time, two types of magma were generated and emplaced in close proximity in this province. Strongly peraluminous P-rich (S-type) melts were formed alongside slightly peraluminous P-poor melts (A-type). Two suites of strongly peraluminous P, F, Li, Rb, Cs, U, Sn-rich and Zr, Th, Y, HREE-poor magmas were intruded in rapid succession over a period of about 10 Ma (about 330-320 Ma) over the entire region of the Krušné hory. Several peraluminous rhyolitic dykes near Gottesberg mark an isolated event at about 295 Ma. Slightly peraluminous F, Li, Rb, Cs, Sn, Zr, Y, HREE-rich and P-poor magmas were intruded in several events separated in space and time (325-295 Ma). Both magmatic episodes culminated with strongly fractionated subvolcanic granite intrusions, accompanied by explosive brecciation and followed by Sn + W mineralization of greisen type. Successive volcanic eruption of rhyolites and dacites of S-type, and rhyolites of A-type form the fill of the Altenberg-Teplice Caldera (ATC), thus demonstrating the close temporal and spatial relationship between these two types of magma. When these two geochemically distinct types of rock are in direct contact, then the rocks of A-type are always younger. The absolute time difference between the two types can range from less than 1 Ma (the first eruption of the Teplice rhyolite versus the Schönfeld dacite in the ATC) to about 15 Ma (eruption of rhyolites at Gottesberg versus emplacement of the Eibenstock granite). The assumed protolith of all late-Variscan granites in the area of Krušné hory/Erzgebirge is a mixture of fertile quartzo-feldspathic rocks with micaceous metapelites enriched in LILE and Sn + W. The differences in chemical composition of S- and A-type melts originated from local changes in the proportion of quartzo-feldspathic and pelitic lithologies, different pT-conditions of melting, the degree of melting, and the degree of metamorphic dehydratation of the protolith prior to the melting.

  1. Crustal development in relation to granitic magmatism in regard to D/H partition between coexisting hornblende and biotite in the Svecofennian belt

    Directory of Open Access Journals (Sweden)

    Kuroda, Y.

    1993-12-01

    Full Text Available Tie-lines in the ?D-XFe diagram of hornblende and biotite in Japanese island arc granites give commonly a similar slope to that derived from the equation of Suzuoki-Epstein's experimental work ( 1976. This indicates that in the process of granite intrusion in the island arc environment, the water/rock ratio is high enough to allow the presence of molecular water within and around the rock mass crystallizing from the magma. However, the tie-lines of the anorogenic rapakivi granites of Finland (age 1.65-1.54 Ga are quite different from those of island arc granites, i.e. the ?D of hornblende is much lower than that of biotite and the XFe values of both of the minerals are almost the same and high (0.8-0.9. Thus, the tie-lines are nearly vertical. Moreover, the OH contents of hornblende and biotite are very low and this suggests the absence of molecular water in the ascending and crystallizing granitic magma. This probably suggests that the D/H fractionation factor between the hydrous silicates and hydroxyl (OH in the magma without molecular water is different from that of the island arc granites with plenty of molecular water. For the Svecofennian granitic rocks which are older than the rapakivi, e.g. the Turku, Uppsala, Vänge and Revsund masses, the ?D-XFe relationships of hornblende and biotite change systematically following the chronological order of the intrusion. The ?D-XFe relationships of the granitic rocks around Turku are close to those of the island arc granites, those of the Uppsala and Vänge granites show the intermediate patterns between the Turku and Revsund, and those of the Revsund granites are rather similar to rapakivi. It is considered that the geological settings of granitic magmatism in the Svecofennian belt of the Baltic shield developed from a more mobile to a more continental one.

  2. Early Paleoproterozoic (2.5-2.0 Ga) A-type granite associations

    Science.gov (United States)

    Ramo, O. T.

    2010-12-01

    A-type granites (including their volcanic equivalents) and related rocks (mafic intrusions, massif-type anorthosite, basaltic dikes and lavas, rare alkaline rocks) form a conspicuous part of the granite spectrum. They have been recognized by the geological community only relatively recently (first definition of A-type granites by Loiselle and Wones in 1979) and they are characterized by several attributes that clearly set them apart from other granitic rocks. A-type granites were originally defined as relatively dry (anhydrous), and they have high contents of alkali metals (either sodium or potassium) and most high field strength trace elements. They commonly have been emplaced in an extensional tectonic regime not directly related to lithospheric convergence (i.e., they have been considered “anorogenic” or “post-tectonic”). In terms of age, the A-type granites span almost three billion years (~2.7 Ga to Recent) of Earth’s history. Known occurrences of early Paleoproterozoic (2.5-2.0 Ga) A-type granites are relatively few and they are dwarfed by the voluminous mid-Proterozoic (1.7-1.0 Ga) A-type associations of Laurentia, Baltica, and Amazonia. 2.5-2.0 Ga A-type granite suites have been described from the North China craton (2.44, 2.16, 2.09 Ga), northwestern China (2.41, 2.34 Ga), central India (2.50, 2.18 Ga), the West Africa craton (2.07 Ga), the Congo craton (2.3 Ga), South Africa (2.05 Ga), the Karelian craton (2.44, 2.43 Ga), and Labrador (2.05 Ga). Three principal lithologic associations can be recognized for these A-type granite suites: (1) A-type granites in South Africa and Karelia represent the felsic component of layered mafic intrusions and may be very extensive (e.g., the ~30,000 km2 Bushveld granites); (2) high-K granites and syenites emplaced in late/post-orogenic or rift-associated settings (China, India, western and central Africa); and (3) a rare example of pre-2.0 Ga anorthosite-mangerite-charnockite-granite (AMCG) suite in Labrador. A common (yet not ubiquitous) feature of these rock associations is their bimodality with mafic magmatism temporally and spatially associated with the granites. The A-type granites typically contain a major crustal source component, which underlines the significance of crustal melting in the petrogenesis of these rocks. The observation that 2.5-2.0 Ga old A-type granite suites are scarce suggests that, during this period of time, conditions for extensive crustal reorganization were not attained on a global scale. Overall, the early Paleoproterozoic has been considered a time of little net crustal growth on Earth and shortage of “juvenile” crust of this age (e.g., Condie et al. 2005). Thus, in early Paleoproterozoic, there probably was a lack of fertile crustal domains that could have provided the crustal source component for A-type granite associations in regions affected by subcontinental thermal perturbations.

  3. Topaz-albite granites and rare-metal mineralization in the Limu District, Guangxi Province, southeast China

    Science.gov (United States)

    Zhu, Jin-Chu; Li, Ren-Ke; Li, Fu-Chun; Xiong, Xiao-Lin; Zhou, Feng-Ying; Huang, Xiao-Long

    2001-08-01

    The topaz-albite granites of the Limu district are ultra-acidic, peraluminous, Li-F-Na-rich and Sn-Ta-Nb-mineralized. A distinct vertical zonation is developed in the granite stocks. There is an upward, systematic transition from leucocratic microcline-albite granite, through albite-microcline granite, topaz-albite granite, pegmatite stockscheider and layered pegmatite-aplite dikes, to K-feldspar-quartz veins and lepidolite-fluorite stringers in the country rocks. Snow-ball textures, homogeneous distribution of rock-forming and accessory minerals, disseminated mineralization, and melt inclusions in quartz, topaz, and albite are typical features indicative of their crystallization from the late stage Li-F-Na-rich and Sn-Ta-Nb-bearing residual granitic melts at a higher intrusion level. A comparison with rare-metal-bearing pegmatite, ongonite, topaz rhyolite and obsidian glass from other regions shows the worldwide existence of these specialized residual melts. Their emplacement and crystallization in a variety of geological environments result in the formation of a series of chemically similar rocks with different petrographic textures and mineral associations. The topaz-albite granites and associated mineralization in the Limu district provide a good example of highly evolved magmatic fractionation in the F-rich granite system and fluid/melt partitioning behavior of rare-metal elements during magmatic-hydrothermal evolution.

  4. Geology, geochemistry, and geochronology of an A-type granite in the Mulock Glacier area, southern Victoria Land, Antarctica

    International Nuclear Information System (INIS)

    On the north side of the Mulock Glacier and at Cape Teall in southern Victoria Land, Antarctica, deformed greenschist facies Skelton Group metasediments are intruded by the post-kinematic A-type Mulock Granite. Geochemical data indicate that this intrusive complex is similar to A-type granitoids previously described both to the north (Glee Intrusives and Penny Hill Granite), where they form part of the Koettlitz Glacier Alkaline Province, and to the south (Foggydog Granite Suite). A U-Pb zircon date of 546 ± 3 Ma on the Mulock Granite places a minimum constraint on the age, and timing of deformation of the Skelton Group rocks in this area, and indicates that the Mulock Granite was emplaced during the initial stages of the Ross Orogeny. This age also confirms that crystallisation of this granite body was synchronous with that of A-type granitoids from the Royal Society Range to Skelton Glacier area immediately to the north. (author). 60 refs., 7 figs., 2 tabs

  5. Mineral chemistry and geochemistry of the Late Neoproterozoic Gabal Abu Diab granitoids, Central Eastern Dessert, Egypt: Implications for the origin of rare metal post-orogenic A-type granites

    Science.gov (United States)

    Sami, Mabrouk; Ntaflos, Theodoros; Farahat, Esam S.; Ahmed, Awaad F.; Mohamed, Haroun A.

    2015-04-01

    The Neoproterozoic Gabal Abu Diab pluton is a part of the Arabian Nubian shield (ANS) continental crust and located in the Central Eastern Desert (CED) of Egypt. It constitutes multiphase granitic pluton intruded into granodiorite and metagabbro-diorite rocks with sharp and nonreactive contacts. Based on field observations, colors, structural variations and petrographic investigations, this granitic outcrop consists of an inner core of two-mica granite (TMG) followed outward by garnet bearing muscovite granite (GBMG) and albite granite (AG). Petrographical study indicated that medium to coarse-grained TMG is dominated by K-feldspar (Or88-98), quartz, plagioclase (albite, An0-7), muscovite and biotite with hypidiomorphic texture. With exception the appearance of garnet and the disappearance of biotite the GBMG resembles the TGM, while AG is leucocratic without any mafic mineral. The main accessories are zircon, Nb and Ta-bearing rutile, columbite, ilmenorutile, ilmenite, magnetite and apatite. This mineralogical similarity and the existence of columbite group minerals (CGM) in all granitoids, indicates a cogenetic relationship. Microprobe analyses reveal that, besides the CGM, rutile and ilmenite are the main repository phases for Nb-Ta-Ti. Columbite-(Mn) exists as individual subhedral crystals (up to 100?m in size) or intimate intergrowth with Nb-bearing rutile and/or ilmenite. The CGM are represented mostly by columbite-(Mn) with Ta/(Ta+Nb) and Mn/(Mn+Fe) ratio ranging from 0.02-0.08 and 0.4-0.9, respectively suggesting extreme degree of magmatic fractionation. Rutile contains significant amounts of Ta (up to 4 wt.% Ta2O5) and Nb (up to 22 wt.% Nb2O5). Biotites are phlogopite-annite in composition (Ann47-60Phlog40-53,on average) and are enriched with AlIV that characterize peraluminous granites. Garnets contain 60-69 mol.% spessartine and 28-36 mol.% almandine where, the ratio of spessartine and almandine together exceeds 95 mole percent, similar to garnet occur within A-type granite worldwide. According to Zhang et al., 2012, the garnet crystallized at the expense of biotite from the MnO-rich evolved melt after fractionation of biotite, plagioclase, K-feldspar, zircon, apatite, and ilmenite. The granitoids are alkali feldspar granites showing distinct geochemical features and most likely, belong to the post-orogenic younger Egyptian granitoids. They are peraluminous A-type alkaline rocks but they have lower Fe2O3, MgO, MnO, CaO, TiO2, P2O5, Sr, Ba, V, and higher SiO2, Na2O, K2O, Nb, Ta, U, Zr, Th, Ga/Al and Rb than the typical rocks of this type. The positive correlation between Ba and Sr, and the negative correlation between Rb and K/Rb reveal fractional crystallization of alkali feldspar. The similarity in most geochemical characteristics suggests that Abu Diab granitoids are genetically related to each other and extremely enrichment in incompatible elements such as Nb and Ta, indicating that they crystallized from extremely differentiated magmas. References: Zhang, J., Ma, C. and She, Z., 2012. An Early Cretaceous garnet-bearing metaluminous A-type granite intrusion in the East Qinling Orogen, central China: Petrological, mineralogical and geochemical constraints. Geoscience Frontiers 3 (5), 635-646.

  6. Geothermal potential of Caledonian granites underlying Upper Palaeozoic sedimentary basins astride the Iapetus Suture Zone in Ireland

    Science.gov (United States)

    Fritschle, Tobias; Daly, J. Stephen; Whitehouse, Martin J.; McConnell, Brian; Buhre, Stephan

    2014-05-01

    Upper Palaeozoic sedimentary basins in Ireland overlie crystalline rocks within the Caledonian Iapetus Suture Zone. Beneath these basins, Lower Palaeozoic rocks, formed and deformed during the Caledonian orogenic cycle, were intruded by c. 420-390 Ma late-tectonic granites at various tectonic levels. These include the subsurface Kentstown and Glenamaddy granites discovered by mineral exploration drilling. While these granites comprise actual targets for Enhanced Geothermal System (EGS) exploration, several others likely exist based on geophysical considerations. In order to test the regional geothermal potential, the buried granites as well as analogue exposed rocks are being investigated geochemically. The geothermal potential of the intrusives depends on their heat production rate (HPR), which is calculated using rock density and concentrations of the heat producing elements (HPE) uranium, thorium and potassium. In spite of their close spacing and similar ages, the whole-rock geochemistry of the granites varies significantly, but with no obvious geographical control (Fritschle et al., 2013; 2014). The granite HPR values range from 1.4 ?W/m3 for the Dhoon Granite (Isle of Man) to 4.9 ?W/m3 for the Drogheda Granite (Ireland). This compares with the average HPR for a 'typical' granite of 2.7 ?W/m3 (Goldstein et al., 2009). It is demonstrated that an elevated HPR of a granite can be related to enrichment in one of the HPE alone (e.g., uranium-enrichment in the Foxdale Granite (Isle of Man), or thorium-enrichment in the Drogheda Granite). Enrichment in HPE in a granite may occur due to different reasons including hydrothermal (re-) distribution of uranium, or the assimilation of thorium-rich wall-rocks. Hence, the distribution of the HPE in particular minerals, veins and source lithologies, along with the petrophysical characteristics of the sedimentary basins and the granites' petrogenesis, are currently being investigated as possible mechanisms controlling their heat production budget. Fritschle, T., Daly, J.S., Whitehouse, M.J., McConnell, B., Buhre, S., 2013. U-Pb Zircon Ages from Granites in the Iapetus Suture Zone in Ireland and the Isle of Man. Mineralogical Magazine, 77(5): 1115. Fritschle, T., Daly, J.S., Whitehouse, M.J., McConnell, B., Buhre, S., 2014. Zircon geochronology and Hf-O isotope geochemistry from granites in the Iapetus Suture Zone in Ireland and the Isle of Man. This issue. Goldstein, B.A., Hill, A.J., Long, A., Budd, A.R., Ayling, B., Malavazos, M., 2009. Hot rocks down under - evolution of a new energy industry. Geothermal Resources Council Transactions, 33: 185-198.

  7. The Neocene Magmatism in South Gangdese, Tibet and its tectonic significance: Evidences from Namuru Granitic Complex

    Science.gov (United States)

    Dong, G.; Mo, X.

    2011-12-01

    There are lots of granitic intrusions in the western Gangdese, Tibet. Namuru granite complex is one of the typical intrusions with various gabbro inclusions and mafic micro-granular enclaves (shortly MME). Field investigation has found the gradually transitional relationship between the gabbro inclusions and granite with abundant MMEs. It is lithologically biotite granite and few granodiorite for Namuru complex. The chemical analyses show that the SiO2 varies from 65-76%, average 73% for the granite and 48.5-55.6%, average 51%. The total alkali contents are high in both the granite (K2O+Na2O= 5.50%~8.71%) and mafic rocks (4.42~6.7%). The REE pattern is flat and slightly declining with no clearly Eu anomaly with the total content from up to 284.75ppm and lowest of 105.35ppm in the granite and up to 120.38ppm, and lowest 72.48×10-6 in the gabbro rocks. The normalized trace element spider is quite similar in the both with K element enriched and Nb, Ti depleted. Zircon LA-ICP-MS U-Pb dating for 4 samples both granite and gabbro inclusions gave the age of 46.11±0.78Ma, 45.47±0.4Ma, 46.7±2.9Ma and 45.4±1.4Ma respectively, falling into a range of 45.4-46.7Ma of crystalling age. All the characters indicated that magma mixing had happened between granite and mafic magma during the Neocene (45.4-46.7Ma), forming the vast granitic and gabbro rocks as an important magmatic event in western Gangdese. It happens to be consistent with the duration (40.0-52.5Ma) for the known magma mixing and underplating in eastern to middle Gangdese, such as Quxu and Xigarze. It probably represents the giant magma event with magma mixing and underplating in Gangdese during early Neocene. Therefore it was inferred, on the basis of magmatic rocks, that the collision between India-Eurasian continents are acting simultaneously in both eastern and western Gangdese in Eocene, resulting in basaltic magma underplating below and then magma mixing along whole Gangdese belt and formation of the Gangdese giant magmatic belt. This event post-dated the initiation of India-Eurasia continental collision by 15 million years and was contemporaneous as a process from east to west of Gangdese. It is believed that it is the mixed magma during early stage of continental collision that invade up in the crust along Gangdese belt, forming the Gangdese giant magma belt.

  8. Uranium and other microelement ditribution in granites and host rocks of Kumyshtag mass (Northern Tien Shan)

    International Nuclear Information System (INIS)

    Behaviour of uranium and other micro-elements for stating the dependence of their distribution in granites and enclosing rocks on the conditions of magma crystallization is considered. Distribution of the mentioned elements is characterized with account of geological and petrological factors and carbon isotope composition in inclusions of the volatile phase in granite minerals. Uranium weakly migrated in the volatile phase during the intrusive formation; uranium migration increases by the end of granite crystallization when melt acidity and its saturation with uranium grow to the utmost. Matter mass transfer in time covered magmatic-autometasomatic stages and proceeded on the background of sharp increase of the melt acidity. The main tendency in substance migration is evacuation of strong bases and accumulation of amphoteric elements including uranium

  9. Geothermal potential of Caledonian granites in Ireland and the Isle of Man: Implications from hydrothermal alteration

    Science.gov (United States)

    Fritschle, Tobias; Daly, J. Stephen; Whitehouse, Martin J.; Buhre, Stephan; McConnell, Brian; The Iretherm Team

    2015-04-01

    Ordovician to Devonian (Caledonian) granites are common in the Iapetus Suture Zone (ISZ) in Ireland and Britain. Some of these, e.g., the buried Kentstown and Glenamaddy granites, are situated beneath Upper Palaeozoic sedimentary basins, and hence are potential geothermal targets. Numerous granites of similar age and related origin (Fritschle et al., 2014) are exposed astride the ISZ. They are considered to be analogous to the buried ones, and their geochemical characteristics are used as a proxy for the buried granites as samples from deep drilling are naturally limited. The whole-rock geochemistry of nine granite intrusions (71 samples, including both hydrothermally altered and unaltered samples) varies significantly, but with no obvious geographical control. The granites are S- and I-Types with ASI (Aluminium Saturation Index) between 0.7 - 1.4. Average heat production rates range from 1.4 ?W/m³ for the Leinster Granite to 4.9 ?W/m³ for the Drogheda Granite (Fritschle et al., 2015). The heat-producing elements uranium (U), thorium (Th) and potassium (K) and calculated heat production rates generally correlate positively with niobium and rubidium concentrations. However, S-Type compared to I-Type granites show elevated abundances in rubidium (>130 ppm) and usually have a lower Th/U ratio. Altered samples tend to have a higher Th/U ratio compared to unaltered ones. Within individual plutons trends of decreasing heat production rates with increasing Th/U ratios were observed. This trend is attributed to the hydrothermal redistribution of the mobile heat-producing element uranium. This is also implied by uranium-enrichment in hydrothermally generated Ca and Si-veinlets. Metasomatic processes such as hydrothermal alteration appear capable of significantly redistributing mobile elements such as uranium. Hence, these processes may act as a major mechanism controlling the granite's heat production budget, often shaping a pluton's geothermal exploitation potential. Fritschle, T., Daly, J.S., Whitehouse, M.J., Buhre, S., McConnell, B., 2015. Geothermal potential of Caledonian granites astride the Iapetus Suture Zone in Ireland and the Isle of Man - Implications for EGS prospectivity. Proceedings World Geothermal Congress 2015, in press. Fritschle, T., Daly, J.S., Whitehouse, M.J., McConnell, B., Buhre, S., 2014. Zircon geochronology and Hf-O isotope geochemistry from granites in the Iapetus Suture Zone in Ireland and the Isle of Man. Geophysical Research Abstracts 16, EGU-2014-801.

  10. The Torres del Paine intrusion as a model for a shallow magma chamber

    Science.gov (United States)

    Baumgartner, Lukas; Bodner, Robert; Leuthold, Julien; Muntener, Othmar; Putlitz, Benita; Vennemann, Torsten

    2014-05-01

    The shallow magmatic Torres del Paine Intrusive Complex (TPIC) belongs to a series of sub-volcanic and plutonic igneous bodies in Southern Chile and Argentina. This trench-parallel belt is located in a transitional position between the Patagonia Batholith in the West, and the alkaline Cenozoic plateau lavas in the East. While volumetrically small amounts of magmatism started around 28 my ago in the Torres del Paine area, and a second period occurred between 17-16 Ma, it peaked with the TPIC 12.59-12.43 Ma ago. The spectacular cliffs of the Torres del Paine National park provide a unique opportunity to study the evolution of a very shallow magma chamber and the interaction with its host rocks. Intrusion depth can be estimated based on contact metamorphic assemblages and granite solidus thermobarometry to 750±250 bars, corresponding to an intrusion depth of ca. 3km, ca. 500m above the base of the intrusion. Hornblende thermobarometry in mafic rocks agrees well with these estimates (Leuthold et al., 2014). The TPIC is composed of a granitic laccolith emplaced over 90ka (Michel et al., 2008) in 3 major, several 100m thick sheets, forming an overall thickness of nearly 2 km. Contacts are sharp between sheets, with the oldest sheet on the top and the youngest on the bottom (Michel et al., 2008). The granitic laccolith is under-plated by a ca. 400m thick mafic laccolith, built up over ca. 50ka (Leuthold et al. 2012), constructed from the bottom up. Granitic and mafic sheets are themselves composed of multiple metric to decametric pulses, mostly with ductile contacts between them, resulting in outcrop patterns resembling braided stream sediments. The contact of the TPIC with the Cretaceous flysch sediments document intrusion mechanism. Pre-existing sub-horizontal fold axes are rotated in the roof of the TPIC, clearly demonstrating ballooning of the roof; no ballooning was observed in the footwall of the intrusion. Extension during ballooning of the roof is indicated by dykes emanating from the roof of the intrusion into the host rocks. The dykes are perpendicular to the contact, radially shooting into the country rocks. Since the oldest granite is found in the roof, it is also permeated by dykes of successive intrusions. Contact metamorphism can be used to constrain the granite intrusion temperature to ca. 1000°C. Intrusion occurred in multiple pulses along the granite-host rock contact, in rapid succession, before significant cooling occurred in the aureole. Hydration of the biotite and feldspar of the immature sediments in the outer aureole contributed significantly to the overall thermal signature of the host-rock-TPIC system. In contrast, stable isotopes do not document significant fluid circulation. Leuthold, J., Müntener, O., Baumgartner, L., Putlitz, B., Ovtcharova, M., Schaltegger, U. (2012) Time resolved construction of a granitic to mafic laccolith (Torres del Paine, Patagonia). Earth Plan Sci Lett. 325. 85-92 Leuthold J., Müntener O., Baumgartner L.P., Putlitz B., (2014) Recycling of mafic crystal mush, transport and emplacement in the Torres del Paine mafic complex (Patagonia). J. Petrology; accepted pending revision Michel, J., Baumgartner, L.P. Putlitz, B., Ovtcharova, M., Schaltegger, U. (2008) Incremental growth of a shallow crustal laccolith over 80 kyrs: the Torres del Paine Granite, Patagonia. Geology vol. 36, 459-462

  11. Groundwater evolution of the granite area, Korea

    International Nuclear Information System (INIS)

    The geochemistry and environmental isotopes of groundwater in the Cretaceous granite of the Yeongcheon area has been investigated. The hydrochemistry of groundwater belongs to the Ca-HCO3 type. The oxygen-18 and deuterium data are clustered along the meteoric water line, indicating that the groundwater is of meteoric water origin. Tritium data show that the groundwaters were mostly recharged before pre-thermonuclear period and have been mixed with younger surface water flowing rapidly along fractured zones. Based on the mass balance and reaction simulation approaches using both the hydrochemistry of groundwater and the secondary mineralogy of fracture-filling materials, the low-temperature hydrogeochemical evolution of groundwater in the area has been modeled. The results of geochemical simulation show that the concentrations of Ca, Na and HCO3 and pH of waters increase progressively owing to the dissolution of reactive minerals in flow paths. The concentrations of Mg and K first increase with the dissolution of reactant minerals, but later decrease when montmorillonite and illitic material are precipitated respectively. The continuous adding of reactive minerals, i. e. the progressively larger degrees of water/rock interaction, causes the formation of secondary minerals with the following sequence: hematite > gibbsite > kaolinite > montmorillonite > illitic material > microcline. The results of reaction simulation agree well with the observed water chemistry and secondary mineralogy, indicating the successful applicability of this simulation technique to delineate the complex hydrogeochemistry of bedrock groundwaters. (author)

  12. Status of LLNL granite projects

    International Nuclear Information System (INIS)

    The status of LLNL Projects dealing with nuclear waste disposal in granitic rocks is reviewed. This review covers work done subsequent to the June 1979 Workshop on Thermomechanical Modeling for a Hardrock Waste Repository and is prepared for the July 1980 Workshop on Thermomechanical-Hydrochemical Modeling for a Hardrock Waste Repository. Topics reviewed include laboratory determination of thermal, mechanical, and transport properties of rocks at conditions simulating a deep geologic repository, and field testing at the Climax granitic stock at the USDOE Nevada Test Site

  13. Li in minerals from the Ilimaussaq alkaline intrusion, South Greenland

    International Nuclear Information System (INIS)

    Li was analysed by instrumental neutron activation analysis and Cerenkov counting in 120 mineral samples (30 species) from the Ilimaussaq alkaline intrusion, South Greenland. More than 0.23 wt.% Li (0.5 wt.% Li2O) is found in polylitionite, meptunite, riebeckite, Na-cookeite, ephesite, arfvedsonite, gerasimovskite and astrophyllite. Arfvedsonite (200-2500 ppm Li) carreis the bulk of Li in most of the highly alkaline rocks. Li-Mg and Li-F relations indicate that the distribution of Li is controlled by the structure of minerals, their absolute contents of Mg and F and the fractionation stage within the intrusion. Li is probably linked with F in the fluid state and this linkage continues into crystallising phases where Li occupies sites which also accommodate Mg. Li/Mg and LI/F ratios of Ilimaussaq rocks and minerals are higher than in equivalent materials from the Lovozero intrusion (Kola, Russia). The Li-Mg-Fe2+ geochemical association at Ilimaussaq (Fe2+>>Mg) and Lovozero (Fe2+mG) contrasts with the commercially important Li-rich but Mg-Fe2+-poor association found in certain granite pegmatites and greisenised granites. (au) (43 refs.)

  14. MORPHOMETRY OF ZIRCON FROM BETLIAR GRANITE

    Directory of Open Access Journals (Sweden)

    Jakabská Katarína

    1997-10-01

    Full Text Available Morphometrical analyse has been provided, using the method of [10] , on zircon from granite porphyry at Betliar. The result of this investigation indicate a comagmatic origin of Betliar and other granite bodies in the Gemericum. The source materila for at the granite magma formation originated by hybridization of crust-mantle rocks.

  15. MORPHOMETRY OF ZIRCON FROM BETLIAR GRANITE

    OpenAIRE

    Jakabská Katarína

    1997-01-01

    Morphometrical analyse has been provided, using the method of [10] , on zircon from granite porphyry at Betliar. The result of this investigation indicate a comagmatic origin of Betliar and other granite bodies in the Gemericum. The source materila for at the granite magma formation originated by hybridization of crust-mantle rocks.

  16. Geochronological and geological studies on a granite of higher Himalaya, North-East of Manikaran, Himachal Pradesh

    International Nuclear Information System (INIS)

    Rb-Sr whole-rock data is presented for a biotite-granite of Central Crystallines. The whole-rock isochron age is found to be 467 +- 45 m.y. This should represent the time of intrusion of the granite. A brief account of the geology and petrography is also presented. The age of the biotite is found to be 8.8 +- 2.0 m.y., which is the youngest Rb-Sr age reported so far for a mineral from the Himalaya. This fixes the period when the rocks of this area, after being heated and uplifted, cooled to a temperature of about 3000C. (author)

  17. The late- to postorogenic transition in the Neoproterozoic Agudos Grandes Granite Batholith (Apiaí Domain, SE Brazil): Constraints from geology, mineralogy, and U Pb geochronology

    Science.gov (United States)

    Leite, Renato Jordan; Heaman, Larry M.; de Assis Janasi, Valdecir; Martins, Lucelene; Creaser, Robert A.

    2007-02-01

    The latest evolution of the Neoproterozoic Agudos Grandes Batholith (Apiaí domain, SE Brazil) is marked by an important change in the type of granitic magmatism. The "late-orogenic" Piedade, Roseira, Serra dos Lopes, and Pilar do Sul granites are elliptical plutons with roughly concentric zoning and a spatial arrangement suggesting a continuous southwestward migration of the magmatic focus. The main rock types are "contaminated" calc-alkaline granites that range from mafic-rich (color index > 10), porphyritic biotite (±muscovite) granite-granodiorite in Piedade to pink, equigranular, muscovite-biotite leucogranite (CI border of the Paranapanema plate; the younger, approximately 565 Ma group is represented by two elongated plutons (Serra da Batéia and Serra da Queimada) that seem to reflect coeval orogenic events farther east in the Ribeira belt. The modal composition, magnetic susceptibility, and mafic mineral chemistry of the late-orogenic granites are consistent with an origin by contamination of metaluminous, oxidized, calc-alkaline magmas with crustal melts.

  18. Developing services for younger people with dementia.

    Science.gov (United States)

    Jubb, Dennis; Pollard, Nick; Chaston, Denise

    The services available for younger people with dementia (typically between 45 and 65 years of age) are underdeveloped. This article describes how one trust has addressed the problem through a 'coffee shop' project. This drop-in facility allows younger people with dementia and their carers to meet informally, support each other and access a range of services, such as counselling, medical information, help with benefits and legal advice. PMID:12808749

  19. Intrusion Detection System: Overview

    CERN Document Server

    Alanazi, Hamdan O; Zaidan, B B; Zaidan, A A

    2010-01-01

    Network Intrusion Detection (NID) is the process of identifying network activity that can lead to the compromise of a security policy. In this paper, we will look at four intrusion detection approaches, which include ANN or Artificial Neural Network, SOM, Fuzzy Logic and SVM. ANN is one of the oldest systems that have been used for Intrusion Detection System (IDS), which presents supervised learning methods. However, in this research, we also came across SOM or Self Organizing Map, which is an ANN-based system, but applies unsupervised methods. Another approach is Fuzzy Logic (IDS-based), which also applies unsupervised learning methods. Lastly, we will look at the SVM system or Support Vector Machine for IDS. The goal of this paper is to draw an image for hybrid approaches using these supervised and unsupervised methods.

  20. Geochemical, petrological, geo dynamic and radiometric age dating investigation of Aqdarreh intrusion massive (north of Takab) northwest of Iran

    International Nuclear Information System (INIS)

    Aqdarreh intrusi body with an area of 30 km 2 is located in 34 km north of Takab, northwest of Iran. This batholith is situated in Central Iran, cutting Paleozoic rocks. Radiometric age of Aqdarreh batholith by K-Ar method is 48.38 m. a.,corresponding to Eocene magmatism. Aqdarreh intrusive body consists of tonalite, granodiorite, alkali feldspar granite and monzogranite in which the main mafic mineral is biotite. Further more, there is not any enclave in these rocks. Study of the investigated samples shows that Aqdarreh intrusive rocks have two different generations. Part of the collected samples belongs to I-type granite (calc-alkaline) and others represent the A-type granite (alkaline). It seems that this process is created by the contamination of alkaline magma by crustal materials. Geochemistry of the rare earth elements shows that the tectonic setting of the body is compatible with Post Orogenic Granitoids

  1. Intrusion detection: systems and models

    Science.gov (United States)

    Sherif, J. S.; Dearmond, T. G.

    2002-01-01

    This paper puts forward a review of state of the art and state of the applicability of intrusion detection systems, and models. The paper also presents a classfication of literature pertaining to intrusion detection.

  2. Interrelations between extensional shear zones and synkinematic intrusions: The example of Ikaria Island (NE Cyclades, Greece)

    Science.gov (United States)

    Laurent, Valentin; Beaudoin, Alexandre; Jolivet, Laurent; Arbaret, Laurent; Augier, Romain; Rabillard, Aurélien; Menant, Armel

    2015-05-01

    The Aegean extensional backarc domain is an ideal place to investigate the interrelations between syntectonic intrusions and large-scale detachments, understanding whether the intrusions have a triggering effect on the inception of metamorphic core complex formation or not. A new field study of Ikaria Island (NE Cyclades, Greece) in two Miocene granitoid plutons intruding a high-temperature metamorphic dome, namely the Raches and Karkinagrion granites, leads to the identification of a major structure that has been omitted in previous studies: the Gialiskari Detachment. This regional-scale detachment is correlated with the North Cycladic Detachment System. Structural fieldwork at the scale of the entire Raches and Karkinagrion intrusions allows us to propose a map of strain intensity in these granites. This map, based on macrostructural criteria, highlights a strong strain gradient in both intrusions from base to top, when approaching the Gialiskari Detachment. Along the strain gradient, a continuum of top-to-the north shearing deformation is recognized, including i) syn-magmatic deformation, ii) high-temperature ductile deformation at submagmatic state, iii) mylonitic to ultramylonitic deformation, and iv) low-temperature brittle deformation. A scenario of the interactions between the detachment and the Raches and Karkinagrion intrusions during their emplacement is proposed. We show that these granites were emplaced while the exhumation of the Ikaria metamorphic dome was already underway. We conclude that these plutons do not initially localize detachments, and instead that detachments localize and control the ascent of plutons. Intrusions then interact with detachments, accommodating their upward migration in the crust. This scenario is described on other Cycladic islands such as on Tinos or Mykonos. At a larger scale, the final emplacement of plutons may result from the flow of molten crust toward metamorphic core complex during extension.

  3. Intensive low-temperature tectono-hydrothermal overprint of peraluminous rare-metal granite: a case study from the Dlhá dolina valley (Gemericum, Slovakia)

    Science.gov (United States)

    Breiter, Karel; Broska, Igor; Uher, Pavel

    2015-02-01

    A unique case of low-temperature metamorphic (hydrothermal) overprint of peraluminous, highly evolved rare-metal S-type granite is described. The hidden Dlhá dolina granite pluton of Permian age (Western Carpathians, eastern Slovakia) is composed of barren biotite granite, mineralized Li-mica granite and albitite. Based on whole-rock chemical data and evaluation of compositional variations of rock-forming and accessory minerals (Rb-P-enriched K-feldspar and albite; biotite, zinnwaldite and di-octahedral micas; Hf-(Sc)-rich zircon, fluorapatite, topaz, schorlitic tourmaline), the following evolutionary scenario is proposed: (1) Intrusion of evolved peraluminous melt enriched in Li, B, P, F, Sn, Nb, Ta, and W took place followed by intrusion of a large body of biotite granites into Paleozoic metapelites and metarhyolite tuffs; (2) The highly evolved melt differentiated in situ forming tourmaline-bearing Li-biotite granite at the bottom, topaz-zinnwaldite granite in the middle, and quartz albitite to albitite at the top of the cupola. The main part of the Sn, Nb, and Ta crystallized from the melt as disseminated cassiterite and Nb-Ta oxide minerals within the albitite, while disseminated wolframite appears mainly within the topaz-zinnwaldite granite. The fluid separated from the last portion of crystallized magma caused small scale greisenization of the albitite; (3) Alpine (Cretaceous) thrusting strongly tectonized and mylonitized the upper part of the pluton. Hydrothermal low-temperature fluids enriched in Ca, Mg, and CO2 unfiltered mechanically damaged granite. This fluid-driven overprint caused formation of carbonate veinlets, alteration and release of phosphorus from crystal lattice of feldspars and Li from micas, precipitating secondary Sr-enriched apatite and Mg-rich micas. Consequently, all bulk-rock and mineral markers were reset and now represent the P-T conditions of the Alpine overprint.

  4. Intensive low-temperature tectono-hydrothermal overprint of peraluminous rare-metal granite: a case study from the Dlhá dolina valley (Gemericum, Slovakia

    Directory of Open Access Journals (Sweden)

    Breiter Karel

    2015-02-01

    Full Text Available A unique case of low-temperature metamorphic (hydrothermal overprint of peraluminous, highly evolved rare-metal S-type granite is described. The hidden Dlhá dolina granite pluton of Permian age (Western Carpathians, eastern Slovakia is composed of barren biotite granite, mineralized Li-mica granite and albitite. Based on whole-rock chemical data and evaluation of compositional variations of rock-forming and accessory minerals (Rb-P-enriched K-feldspar and albite; biotite, zinnwaldite and di-octahedral micas; Hf-(Sc-rich zircon, fluorapatite, topaz, schorlitic tourmaline, the following evolutionary scenario is proposed: (1 Intrusion of evolved peraluminous melt enriched in Li, B, P, F, Sn, Nb, Ta, and W took place followed by intrusion of a large body of biotite granites into Paleozoic metapelites and metarhyolite tuffs; (2 The highly evolved melt differentiated in situ forming tourmaline-bearing Li-biotite granite at the bottom, topaz-zinnwaldite granite in the middle, and quartz albitite to albitite at the top of the cupola. The main part of the Sn, Nb, and Ta crystallized from the melt as disseminated cassiterite and Nb-Ta oxide minerals within the albitite, while disseminated wolframite appears mainly within the topaz-zinnwaldite granite. The fluid separated from the last portion of crystallized magma caused small scale greisenization of the albitite; (3 Alpine (Cretaceous thrusting strongly tectonized and mylonitized the upper part of the pluton. Hydrothermal low-temperature fluids enriched in Ca, Mg, and CO2 unfiltered mechanically damaged granite. This fluid-driven overprint caused formation of carbonate veinlets, alteration and release of phosphorus from crystal lattice of feldspars and Li from micas, precipitating secondary Sr-enriched apatite and Mg-rich micas. Consequently, all bulk-rock and mineral markers were reset and now represent the P-T conditions of the Alpine overprint.

  5. Geology and geochemistry of the Redrock Granite and anorthosite xenoliths (Proterozoic in the northern Burro Mountains, Grant County, New Mexico, USA

    Directory of Open Access Journals (Sweden)

    Virginia T. McLemore

    2002-01-01

    Full Text Available Mineral ages from the A-type granites and anorthosite xenoliths in the Redrock area in the northwestern Burro Mountains in southwestern New Mexico cluster around ~1220–1225 Ma and provide yet another example of bimodal igneous activity during this time period in the southwestern United States. The metaluminous to peraluminous, marginally alkaline to subalkaline Redrock Granite exhibits the textural, mineralogical, and geochemical features of A-type granitethat was emplaced at a relatively high crustal level. Field relationships, whole rock and mineral geochemical and isotopic trends suggest that the four phases of the Redrock Granite are genetically related, with the miarolitic biotite/alkali feldspar granite being the youngest phase. Spatial relationships and geochemical data suggest that the anorthosite xenoliths were coeval with the RedrockGranite, which is consistent with the anorthosite being derived from the upper mantle, possibly due to deep mantle upwellings, and the Redrock Granite from the lower crust. The process involved melting in the upper mantle, emplacement of anorthosite in the crust resulting in partial crustal melting and thinning, and, finally, intrusion of shallow silicic plutons, the Redrock Granite. The Redrock Granite and anorthosite were presumably derived from sources characterized by subtle, long-term LREE depletion, with ?Nd (at 1220 Ma values on theorder of +1 to +2.

  6. Cretaceous evolution of the Adria-Europe plate boundary: succession of events recorded in granites and enclaves of the Moslava?ka Gora (Croatia)

    Science.gov (United States)

    Petrinec, Zorica; Balen, Dražen

    2014-05-01

    Complex Cretaceous S-type granitoid pluton, geotectonically related to an active continental margin, makes a central part of the Moslava?ka Gora (MG) crystalline and hosts two groups of enclaves. Cognate enclaves, genetically related to the granitoid host rocks, comprise different types of microgranular enclaves, tourmaline nodules, K-feldspar megacrysts and other inhomogenities found inside the two-mica granitoids. All of these enclaves provide evidence of the petrogenetic processes that took place inside the MG Cretaceous magmatic system. On the other hand, foreign enclaves, mostly xenoliths of metapelitic and metabasic rocks, hold information about the metamorphic events that preceded or were contemporaneous with the intrusion and solidification of the igneous body. Based on the age data gathered by earlier researchers of the MG crystalline and P-T data extracted from the study of Cretacoeus granitoids and their enclaves, it was possible to characterize multiple episodes of Cretaceous igneous and metamorphic evolution of the MG. Intrusion of the mantle-related mafic magma at pressures ~8 kbar and temperatures ~920 °C has been regarded as the oldest Cretaceous magmatic pulse (~110-90 Ma) recorded in the MG crystalline complex, leaving behind local occurrences of gabbroic rocks. Its relation to the medium-pressure metamorphic event recorded in amphibole-bearing xenoliths reaching ~8 kbar and max. ~800 °C has not been elucidated so far. It was followed by a younger LP-HT event (100-90 Ma), recorded in a sequence of partial melting reactions in the metapelitic rocks reaching granulite facies conditions (2-5 kbar, ~720-790 °C). Such melt-producing reactions documented in the km-sized metapelitic xenoliths point to the nature and extent of processes in the metapelitic source rocks that contributed to the overall production of the granitic magma in this setting. All of the aforementioned events preceded the Late Cretaceous intrusion of the central granitoid body and oscillations of igneous activity recored in the products of mixing and hybridization between granitoids and more mafic magmas (MME enclaves) and the onset of immiscibility (tourmaline nodules) nad the intrusion of leucogranites. According to our data, all of these pulses occurred in a low-pressure crustal setting (enclaves, recording the interaction of granitoid host with the encapsulated fragments of metapelitic rocks and their role in the granite petrogenesis at Moslava?ka Gora. Data gathered by the study of different types of enclaves from the Moslava?ka Gora granitoid rocks are mutually consistent and reflect the complexity of Cretaceous evolution of a small and geotectonically still enigmatic crystalline fragment at the Adria-Europe plate boundary. This approach opens new perspectives for future research of the processes that took place in the mobile zone on the southeastern margins of Mesozoic Europe.

  7. Colorectal cancer in younger population: our experience

    International Nuclear Information System (INIS)

    Objective: To promote awareness regarding increased occurrence of colorectal cancer in younger population and its clinicopathological features compared to older patients. Methods: The cross-sectional study was conducted from February 2010 to January 2011 on patients with diagnosis of colorectal carcinoma admitted through emergency or outpatient departments to Surgical Unit 5, Civil Hospital, Karachi. Data regarding age, gender, presentation, site of tumour, surgery performed and Dukes staging was collected and analysed. Results: A total of 23 patients were operated during the study period: 13 (56.52%) males and 10 (43.47%) females. Of them 12 (52.17%) were below the age of 40 years, while 3 (13.04%) patients were in the 11-20 age group. In 7 (30.4%) patients, tumour was irresectable at the time of presentation so a palliative procedure (diversion colostomy or ileostomy) was performed. There was a higher proportion of younger patients with metastatic disease at the time of presentation (n=9; 75%) while 10 out of 12 patients in the younger age group (83.3%) had a tumour of left colon, particularly rectum. Conclusion: Although colorectal cancer is usually a disease of older patients, it is increasingly becoming more common in younger population. Data suggests a leftward distribution for colorectal carcinoma and that younger patients present with more advanced disease and poorer prognosis. (author)

  8. Southern complex: geology, geochemistry, mineralogy, and mineral chemistry of selected uranium- and thorium-rich granites

    International Nuclear Information System (INIS)

    Four major rock groups are defined in the Southern Complex: the Bell Creek Granite (BCG), the Clotted Granitoids (CGR), the Albite Granite (AGR), and the Migmatite Complex. Metatexites of the Migmatite Complex are the oldest rocks and include paleosome of a metasedimentary and metavolcanic protolith represented by Banded Iron Formation, Banded Amphibolite, and Banded Gneisses, and interlayered or crosscutting leucogranites. The CGR span the range from metatexite to diatexite and represent in-situ partial melting of metapelitic layers in the protolith during intrusion of the BCG. The BCG cuts the migmatites, is locally cut by the CGR, and was derived by partial melting of a dominantly metasedimentary protolith at some depth below the presently exposed migmatites during a regional tectonothermal event. The Albite Granite is a 2km diameter, muscovite-fluorite-columbite-bearing intrusive stock that cuts all other major units. The thorium history of the BCG is a function of the history of monazite. The thorium history of the CGR is also dominated by monazite but the thorium content of this unit cannot be entirely accounted for by original restite monazite. The uranium history of the BCG and CGR was dominated by magmatic differentiation and post magmatic, metamorphic and supergene redistributions and is largely independent of the thorium history. The thorium and uranium history of the AGR was dominated by magmatic/deuteric processes unlike the BCG and CGR unlike the BCG and CGR

  9. Extra-terrestrial igneous granites and related rocks: A review of their occurrence and petrogenesis

    Science.gov (United States)

    Bonin, Bernard

    2012-11-01

    The telluric planets and the asteroid belt display the same internal structure with a metallic inner core and a silicate outer shell. Experimental data and petrological evidence in silicate systems show that granite can be produced by extreme igneous differentiation through various types of igneous processes. On Moon, 4.4-3.9 Ga granite clasts display dry mineral assemblages. They correspond to at least 8 discrete intrusive events. Large K/Ca enrichment and low REE abundances in granite relative to KREEP are consistent with silicate liquid immiscibility, a process observed in melt inclusions within olivine of lunar basalts and in lunar meteorites. Steep-sided domes identified by remote sensing can represent intrusive or extrusive felsic formations. On Mars, black-and-white rhythmic layers observed on the Tharsis rise along the flanks of the peripheral scarps of the Tharsis Montes giant volcanoes suggest the possible eruption of felsic pyroclastites. Though no true granites were found so far in the Martian SNC meteorites, felsic glasses and mesostases were identified and a component close to terrestrial continental (granitic) crust is inferred from trace element and isotope systematics. Venus has suffered extensive volcanic resurfacing, whereas folded and faulted areas resemble terrestrial continents. Near large shield volcanoes, with dominant basaltic compositions, steep-sided domes have been interpreted as non-degassed silicic extrusions. The hypothesis of a granitic component is "tantalising". Extra-terrestrial granite is frequently found as clasts and mesostases in asteroidal meteorites. Porphyritic textures, with alkali feldspar crystals up to several centimetres in size, were observed in silicate enclaves within iron meteorites. In the chondrite clan, polymict breccias can contain granitic clasts, whose provenance is debated. One clast from the Adzhi-Bogdo meteorite yields a 4.53 ± 0.03 Ga Pb-Pb age, making it the oldest known granite in the solar system. The vast majority of granitic materials recognised so far in the extra-terrestrial record are characterised by ferroan A-type compositions, characterised by high to very high K2O and medium CaO contents, sodic varieties being exceedingly rare. Textural evidence of graphic quartz-alkali feldspar intergrowths within crystallised products suggests that they are igneous in origin and crystallised quickly from a liquid. In water-depleted to water-free environments, fluorine and chlorine can play significant roles, as their effects on liquidus temperatures and crystallising assemblages are nearly identical to those of water. The distribution of alkalis and alkaline earths cannot be related only to extensive crystal fractionation, but is likely induced by supplementary silicate liquid immiscibility. Medium-temperature silicate liquid immiscibility is well known as a mode of differentiation in experimental petrology studies at very low pressures on systems dominated by Fe, Ti, K, and P as major elements. The ultimate question is, therefore, not whether granite (s.l.) occurs in any given planetary body, but if sufficient volumes of granitic materials could have been produced to constitute stable continental nuclei.

  10. TOWARD A NEW PARADIGM FOR GRANITE GENERATION

    OpenAIRE

    Vigneresse, Jean Louis

    2004-01-01

    Ideas about granite generation have evolved considerably during the last two decades. The present paper lists what ideas were accepted and later modified, concerning the processes acting during the four stages of granite generation: melting, melt segregation and ascent, and emplacement. The active role of the mantle constitutes a fifth stage. Fluid assisted melting, deduced from metamorphic observations, was used to explain granite and granulite formation. Water seepage into meta-sedimentary ...

  11. Age of granites of Wrangel Island metamorphic complex

    Science.gov (United States)

    Luchitskaya, Marina; Sergeev, Sergey; Sokolov, Sergey; Tuchkova, Marianna

    2014-05-01

    Within huge arctic shelf of Eastern-Siberian and Chukchi seas the metamorphic basement (Wrangel complex, Berri Formation) is exposed only on the Wrangel Island. There are different points of views on the age of metamorphic rocks of Wrangel complex (Berri Formation): (1) Neoproterozoic (Kameneva, 1970; Ageev, 1979; Kos'ko et al., 1993, 2003), (2) Devonian (Til'man et al., 1964, 1970; Ganelin, 1989). Metamorphic basement is represented by stratified complex, composed of dislocated metavolcanic, metavolcaniclastic and metasedimentary rocks (schists, metasandstones, metaconglomerated) with single lenses and layers of carbonate rocks (Wrangel Island…, 2003). Among basement rocks in the central part of Wrangel Island there are felsic intrusive bodies. They form small tabular bodies from tens centimeters to 70-80 meters in thickness, rarely dikes and small stocks (up to 20 x 30 m) and are composed of granite-porphyres, rarely muscovite porphyr-like granites and granosyenites (Wrangel Island…, 2003). The age of intrusions allow to determine the age of basement formation. Earlier the age of intrusions was determined by different methods and correlated to the boundary between Neoproterozoic and Paleozoic: K-Ar 570-603 Ma, Pb-Pb 590±50 Ma (S.M. Pavlov, Institute of Precambrian Geology and Geochronology, USSR Academy of Sciences), Rb-Sr 475±31 Ma (I.M.Vasil'eva, Institute of Precambrian Geology and Geochronology, USSR Academy of Sciences), U-Pb 609, 633, 677 Ma (Geological Survey of Canada) (Wrangel Island…, 2003; Kos'ko et al., 1993; Cecile et al., 1991). In the lower part of metamorphic rocks of Wrangel complex there are conformable tabular bodies of gneissosed and foliated granitoides. The latter are meramorphosed and transformed in biotite-muscovite-feldspar-quartz-sericite and muscovite-feldspar-quartz-sericite gneisses and schists, where relics of primary minerals (quartz, plagioclase, potassium feldspar, rarely biotite and muscovite) and equigranular granitic texture are preserved. Accessory minerals of granitoides are zircon, sphene, apatite. During field work of 2006 year the probes for U-Pb SHRIMP zircon datings were collected (upper reaches of Khishchnikov River). Dating was carried out on SHRIMP-II in the Center of Isotopic Studies of Federal State Unitary Enterprize "A.P.Karpinsky Russian Geological Research Institute". Wheited mean ages of zircons from three probes are: 702±3 Ma (N=19), 701±7 Ma (N=3), 707±4 Ma (N=25). They indicate Neoproterozoic age of granitoides. Furthermore, some zircons contain inherited cores, for which following datings were obtained: 1.1; 1,21; 1.107; 1.2-1,4; 1.58; 1.8; 2.6 Ga. These data allow supposing the presence of ancient (Neoproterozoic-Mesoproterozoic) rocks in the basement of Wrangel Island and their participation in the melting process during granite magmas formation. The work was supported by Russian Fund of Basic Researhes projects 13-05-00249, 14-05-00031, Scientific school NSh-2981.2014.5.

  12. Chemical and isotopic studies of granitic Archean rocks, Owl Creek Mountains, Wyoming: Geochronology of an Archean granite, Owl Creek Mountains, Wyoming

    International Nuclear Information System (INIS)

    Rubidium-strontium analyses of whole-rock samples of an Archean granite from the Owl Creek Mountains, Wyo., indicate an intrusive age of 2640 ± 125 Ma. Muscovite-bearing samples give results suggesting that these samples were altered about 2300 Ma. This event may have caused extensive strontium loss from the rocks as potassium feldspar was altered to muscovite. Alteration was highly localized in nature as evidence by unaffected rubidium-strontium mineral ages in the Owl Creek Mountains area. Furthermore, the event probably involved a small volume of fluid relative to the volume of rock because whole-rock ?18O values of altered rocks are not distinct from those of unaltered rocks. In contrast to the rubidium-strontium whole-rock system, zircons from the granite have been so severely affected by the alteration event, and possibly by a late-Precambrian uplift event, that the zircon system yields little usable age information. The average initial 87Sr/86Sr (0.7033 ± 0.0042) calculated from the isochron intercept varies significantly. Calculated initial 87Sr/86Sr ratios for nine apparently unaltered samples yield a range of 0.7025 to 0.7047. These calculated initial ratios correlate positively with whole-rock ?18O values; and, therefore, the granite was probably derived from an isotopically heterogeneous source. The highest initial 87Sr/86Sr ratio is lower than the lowest reported fio is lower than the lowest reported for the metamorphic rocks intruded by the granite as it would have existed at 2640 Ma. Thus, the metamorphic sequence, at its current level of exposure, can represent no more than a part of the protolith for the granite

  13. Contrasting zircon morphology and UPb systematics in peralkaline and metaluminous post-orogenic granite complexes of the Arabian Shield, Kingdom of Saudi Arabia

    Science.gov (United States)

    Aleinikof, J.N.; Stoeser, D.B.

    1989-01-01

    Uzircon ages are reported for seven metaluminous-to-peralkaline post-orogenic granites from the Late Proterozoic Arabian Shield of Saudi Arabia. Zircons from the metaluminous rocks are prismatic, with length-to-width ratios of ??? 2-4: 1 and small pyramidal terminations. In contrast, zircons from three of the four peralkaline complexes either lack well-developed prismatic faces (are pseudo-octahedral) or are anhedral. Some zircons from the peralkaline granites contain inherited radiogenic Pb and have very high common Pb contents (206Pb/204Pb Zircons in the metaluminous granites do not contain inheritance and yield well-defined concordia intercepts. The span of ages of the seven complexes (670-470 Ma) indicates that post-orogenic granitic magmatism was not a singular event in the Arabian Shield but rather occurred as multiple intrusive episodes from the Late Proterozoic to the Middle Ordovician. ?? 1989.

  14. Geochemistry and petrogenesis of the proterozoic granites from Jhabua and Dhar districts, Madhya Pradesh, India and their bearing on uranium mineralisation

    International Nuclear Information System (INIS)

    In the western part of Madhya Pradesh a number of small plutonic granites occur as intrusive into the gneisses and Aravalli metasediments. Granites are of grey, pink colour and gneissic varieties. Mineralogically, the granites are two mica bearing. Chemically they are K2O rich, calc-alkaline, metaluminous to peraluminous and differentiated in nature. Tectonically they are volcanic arc types with an affinity to syn-collisional setup. Basement reactivation may be the cause of the emplacement of these granites as the area is traversed by a number of basement lineaments. They are enriched in light REE with Ce/Yb ratio ranging from 1.4 to 8.4. Negative Eu anomaly (Eu/Eu* 0.2 to 0.8) suggests that they are fractionated. High Th/U ratio (1-18) indicates that uranium has been leached out. Hence the overlying infratrappeans hold potential for litho/structural controlled uranium mineralisation.(author)

  15. Sexual Permissiveness in Younger and Older Adults.

    Science.gov (United States)

    Laner, Mary Riege; Housker, Steve L.

    1980-01-01

    Samples (N=2) of older and samples (N=2) of younger adult respondents, surveyed in 1972 and in 1978 with regard to permissiveness toward specific sexual behaviors, revealed considerable, but not complete, attitudinal similarity between men and women in all groups and increased permissiveness toward nonmarital sexual behaviors among older adults.…

  16. Interior intrusion alarm systems

    International Nuclear Information System (INIS)

    In meeting the requirements for the safeguarding of special nuclear material and the physical protection of licensed facilities, the licensee is required to design a physical security system that will meet minimum performance requirements. An integral part of any physical security system is the interior intrusion alarm system. The purpose of this report is to provide the potential user of an interior intrusion alarm system with information on the various types, components, and performance capabilities available so that he can design and install the optimum alarm system for his particular environment. In addition, maintenance and testing procedures are discussed and recommended which, if followed, will help the user obtain the optimum results from his system

  17. Contrasting Structures and Deformational History of Syntectonic Granites of Campina Grande and Serra Redonda, Borborema Province, NE Brazil

    Directory of Open Access Journals (Sweden)

    Sérgio Wilians de Oliveira Rodrigues

    2011-04-01

    Full Text Available The Campina Grande and Serra Redonda Granites are intrusive along the contact of the Paleoproterozoic basement(Alto Moxotó Domain with the Tonian gneisses (Alto Pajeú Domain of the Borborema Province (northeast Brazil. TheCampina Grande Granite (U-Pb age = 581± 2 Ma shows a concentric oval-shaped structure whereas the Serra RedondaGranite (U-Pb age = 576 ± 3 Ma has a tabular shape, elongated in the NE-SW direction. The plutons are separated bythe left-lateral Galante transcurrent shear zone. In this study, the anisotropy of magnetic susceptibility (AMS was appliedto 64 outcrops of granites to determine the internal structures of these plutons and to explore the relationship betweenmagmatism and deformation in an orogenic setting. The magnetic fabrics are concordant with the metamorphic structure ofthe host rocks. Strike-slip shear zones controlled the emplacement of the Serra Redonda Granite, as indicated by sigmoidalfoliation, defining shear bands associated with the Galante shear zone. In contrast, the magmatic/magnetic fabric of theCampina Grande granite seems to have been produced by body (ascensional forces. The pluton displays an inward dipping, concentric planar fabric parallel to the wall rock contact and lineations highly oblique to the foliation trend. The fabric of the Campina Grande pluton is consistent with a magma moving over a ramp dipping to southwest, with the lineation at high angle to the NE-trending flow direction. The contrasting structures of the plutons reflect the episodic nature of orogenic deformation, which was punctuated by the alternation of weak and strong strains, affecting the fabric development of the syntectonic intrusions.

  18. Perimeter intrusion alarm systems

    International Nuclear Information System (INIS)

    Paragraph 73.50(b)(4) of 10 CFR Part 73 requires at fuel reprocessing plants and other plants processing enriched U, 233U, or Pu that the isolation zone be monitored to detect intruders so that response by the security forces can be initiated. This guide describes six types of perimeter intrusion alarm systems and presents criteria for their performance and use as a means acceptable to NRC for meeting the regulations

  19. Perimeter intrusion sensors

    International Nuclear Information System (INIS)

    To obtain an effective perimeter intrusion detection system requires careful sensor selection, procurement, and installation. The selection process involves a thorough understanding of the unique site features and how these features affect the performance of each type of sensor. It is necessary to develop procurement specifications to establish acceptable sensor performance limits. Careful explanation and inspection of critical installation dimensions is required during on-site construction. The implementation of these activities at a particular site is discussed

  20. Intrusion detection system elements

    International Nuclear Information System (INIS)

    This report highlights elements required for an intrusion detection system and discusses problems which can be encountered in attempting to make the elements effective. Topics discussed include: sensors, both for exterior detection and interior detection; alarm assessment systems, with the discussion focused on video assessment; and alarm reporting systems, including alarm communication systems and dislay/console considerations. Guidance on careful planning and design of a new or to-be-improved system is presented

  1. Geochronological and geochemical constraints on the petrogenesis and geodynamic setting of the Qianlishan granitic pluton, Southeast China

    Science.gov (United States)

    Guo, Chun-Li; Wang, Ru-Cheng; Yuan, Shun-Da; Wu, Sheng-Hua; Yin, Bing

    2015-04-01

    The Qianlishan is a well-known granitic pluton directly related to the super large W-Sn-Mo-Bi polymetallic Shizhuyuan deposit in southeast China. The pluton is composed of three intrusive phases: the first phase of microfine-grained porphyritic biotite granite, the second phase of fine-grained porphyritic biotite granite, and the third phase of medium-grained equigranular zinnwaldite granite. SIMS zircon U-Pb dating yields precise ages for three phases; they are 154.5 and 152.3 Ma, 153.4 and 152.5 Ma, 152.4 and 151.6 Ma, respectively. Overall, all three granite phases contain high SiO2 (73.2-77.7 wt.%) and total alkalis (K2O+Na2O = 7.27-9.36 wt.%). Their aluminum saturation index values increase from 0.91-0.99 for Phase 1, through 0.92-1.01 for Phase 2, to 1.01-1.27 for Phase 3. Average (La/Yb)N ratios are 3.88, 4.12, and 1.06, respectively, in three phases. Compared with Phase 3 granite, the Phase 1 and 2 granites have less conspicuous negative Eu anomalies (Phases 1, 2 Eu/Eu* = 0.13-0.28; Phase 3 Eu/Eu* = 0.01-0.02); Phase 3 granite also shows stronger depletion in Sr, P, Zr, and Ti. Mica compositions change from Mg- and Fe- to Al, F, Li-rich, whereas plagioclase compositions evolve from andesine/oligoclase to albite from Phases 1 to 3 granites. Mineralogical features and whole-rock geochemistry indicate that Phase 3 granite experienced more intensive fractional crystallization than others. The Qianlishan granites have low ? Nd(t) values (-12.9 to -7.9). Zircon ? Hf(t) and ?18O values are -11.1‰ to -5.14‰ and 7.97‰ to 10.35‰, respectively. Two-stage model ages of whole-rock Nd isotopes (1.2-1.9 Ga) and zircon Hf isotopes (1.5-1.9 Ga) indicate that these granites were derived from partial melting of late Paleoproterozoic to early Mesoproterozoic crustal material. Phase 1 and 2 are fractionated I-type granites, and Phase 3 is high-degree fractionated S-type granite. High zirconium saturation temperature (~780 °C) and presence of diopside indicate that these granites originated from partial melting under the relatively high temperature environment. Combined with alkaline basalts, tholeiitic basalts, and intraplate shoshonitic intrusions in time and space, the Qianlishan pluton occurs right within an intercontinental rift along the Qin-Hang deep fault zone in the middle to late Jurassic.

  2. Gravity data inversion as a probe for the 3D shape at depth of granitic bodies

    International Nuclear Information System (INIS)

    Granitic intrusions represent potential sites for waste disposal. A well constrained determination of their geometry at depth is of importance to evaluate possible leakage and seepage within the surroundings. Among geophysical techniques, gravity remains the best suited method to investigate the 3D shape of the granitic bodies at depth. During uranium exploration programmes, many plutons emplaced within different geochemical and tectonic environment have been surveyed. The quality of gravity surveying depends on the intrinsic accuracy of the measurements, and also on their density of coverage. A regularly spaced and dense coverage (about 1 point/km2) of measurements over the whole pluton and its nearby surroundings is needed to represent the gravity effect of density variations. This yields a lateral resolution of about 0.5 kilometer, or less depending on depth and roughness of the floor, for the interpretation of the Bouguer anomaly map. We recommend the use of a 3D iterative method of data inversion, simpler to run when the geometry and distribution of the sources are already constrained by surface data. This method must take into account the various density changes within the granite and its surroundings, as well as the regional effect of deep regional sources. A total error in the input data (measurements, densities, regional field) is estimated at 6%. We estimate that the total uncertainty on the calculated depth values does not exceed ± 15%. Because th values does not exceed ± 15%. Because of good coverage of gravity measurements, the overall shape of the pluton is certainly better constrained than the depth values themselves. We present several examples of gravity data inversion over granitic intrusions displaying various 3D morphologies. At a smaller scale mineralizations are also observed above or close to the root zones. Those examples demonstrate the adequacy of joint studies in constraining the mode of magma emplacement before further studies focussing to environmental problems. 59 refs, 9 figs

  3. Exploration methods for granitic natural stones – geological and topographical aspects from case studies in Finland

    Directory of Open Access Journals (Sweden)

    Olavi Selonen

    2014-06-01

    Full Text Available Regional and local geological constraints for location of natural stone deposits in glaciated terrains of southern and central Finland have been studied and applied to practical exploration for natural stone. A list of geological and topographical aspects to be considered in exploration, is presented. Important aspects refer to: 1. Regional geology of the target area. 2. Magmatism (type and structure of intrusion, relative time of pluton emplacement. 3. Metamorphism (grade, mineral composition, parent material. 4. Deformation (lineaments, shear zones, folding, fault zones, fracture zones, shape preferred mineral orientations, and 5. Topography (relative elevation, micro topography. The proposed aspects can be used as geological guidelines in exploration for granitic natural stones.

  4. A-type stratoid granites of Madagascar: evidence of Rodinia rifting at ca 790 Ma

    Science.gov (United States)

    Nedelec, Anne; Paquette, Jean-Louis; Bouchez, Jean-Luc

    2015-04-01

    The so-called stratoid granites are sheet-like granites emplaced as conformable sills in the Precambrian basement of central Madagascar. Most of them have A-type affinities (Nédélec et al. 1995). They are everywhere characterized by the same structural pattern evidencing two stages of deformation. The first one (foliations mildly dipping to the west and lineations trending WSW) is regarded as the consequence of synkinematic magma emplacement. The second stage, characterized by interference folds, steeply dipping foliations and subhorizontal lineations trending to the north, corresponds to a more or less pronounced reworking in ductile conditions, regarded as the result of Late Pan-African transcurrent tectonics. To the north of Antananarivo, the stratoid granites are associated with comagmatic quartz-syenites. New U-Pb zircons ages obtained by in situ analyses reveal two group of ages: upper intercept ages of ca 790 Ma, and younger ages of ca 550 Ma corresponding to crystal rims. These new data question the geological significance of former TIMS ages of ca 630 Ma formerly obtained from the same rocks (Paquette & Nédélec 1998). It is suggested that the stratoid granites and syenites were emplaced during a crustal thinning event corresponding to an early Rodinia rifting stage. The Pan-African imprint on these rocks is therefore limited to reheating, tectonic reworking and deep fluid transfer in the vicinity of Late-Neoproterozoic shear zones at ca 550 Ma (Nédélec et al. 2014).

  5. Rb-Sr age of Gaik granite, Ladakh Batholith, northwest Himalaya

    International Nuclear Information System (INIS)

    The Gaik Granite is a part of Ladakh batholith outcropping between Gaik and Kiari in NW Himalaya. This is a pink porphyritic granite rich in biotite and poor in hornblende. Rb-Sr analyses have been made on six whole-rock samples of the Gaik Granite. Though the samples are poorly enriched in radiogenic Sr, they define a reliable isochron corresponding to an age of 235+-13(2sigma) m.y. and initial 87Sr/86Sr ratio of 0.7081+-0.0004 (2sigma), Biotite, plagioclase and potash feldspar fractions separated from two of the samples have yielded a much younger mineral isochron at 30+-1.5 m.y. indicating a nearly complete redistribution of Sr isotopes between mineral phases at a time much later than the primary emplacement of the granite. The present results show that at least some components of the Ladakh batholith are of Permo-Triassic aqe. These rocks were isotopically re-equilibrated on a mineral scale during Upper Oligocene in response to the Himalayan orogeny. (author)

  6. A Younger Age for the Universe

    OpenAIRE

    Lineweaver, Charles H.

    1999-01-01

    The age of the universe in the Big Bang model can be calculated from three parameters: Hubble's constant, h; the mass density of the universe, Omega_m; and the cosmological constant, Omega_lambda. Recent observations of the cosmic microwave background and six other cosmological measurements reduce the uncertainty in these three parameters, yielding an age for the universe of 13.4 +/- 1.6 billion years, which is a billion years younger than other recent age estimates. A diffe...

  7. P-T path fluid evolution in the Gross Spitzkoppe granite stock, Namibia

    Directory of Open Access Journals (Sweden)

    Stephen Frindt

    2002-01-01

    Full Text Available The Gross Spitzkoppe granite stock (GSS is a zoned 30 km^2 epizonal intrusion that consists of three main granites: 1 medium-grained biotite granite (marginal, 2 a coarse-grained biotite granite, and 3 a central, porphyritic granite. The stock contains pegmatites as banded marginal stockscheiders and isolated pockets composed of large alkali feldspar and quartz, dark mica, interstitial fluorite, and euhedral topaz and beryl crystals. In the porphyritic granite there are local wolframite-bearing greisens and hydrothermal fluorite and topaz-rich veins.Fluid inclusion studies were conducted on: 1 topaz and quartz crystals from the marginal stockscheider; 2 quartz, topaz, fluorite and beryl crystals from isolated pegmatites; 3 topaz from a miarolitic pegmatite; 4 beryl and quartz veins from greisenized porphyritic granite; and 5 fluorite from a late fluorite vein inthe coarse-grained biotite granite. Preliminary data indicate the presence of three compositionally distinct primary and pseudosecondary inclusion types that are of late magmatic-hydrothermal origin.Type 1. Low salinity (0–10 eq. wt% NaCl H2O (± CO2 inclusions that homogenize to the liquid phase in the temperature range of 300 to 550?C. These inclusions are from quartz, topaz and beryl. Inclusions in fluorite from the fluorite vein homogenize at ~170?C and have a salinity of ca. 1–2 eq. wt% NaCl.Type 2. Saline (25–30 eq. wt% NaCl halite-bearing H2O (± CO2 inclusions that homogenize to the liquid phase in the temperature range of 300 to 400?C. These inclusions are from quartz.Type 3. Low salinity (0–3 eq. wt% NaCl H2O-CO2 inclusions that homogenize to vapor phase in the temperature range of 330 to 550?C. These inclusions are from quartz and topaz.Hydrothermal fluids from greisen minerals are represented by type 1 and type 2 H2O inclusions. They are predominantly of low salinity (~8 eq. wt% NaCl and homogenize to the liquid phase in the temperature range of 300 to 500?C. Isochores for contemporaneous type 2 and type 3 inclusions with homogenization temperature range of 330 to 400?C indicate a maximum trapping pressure of about 900 bar for the marginal stockscheider.

  8. The geology and geochemistry of mafic and intermediate igneous rocks associated with Cape granites

    International Nuclear Information System (INIS)

    Mafic to intermediate rocks, presumably related to the Cape Granite Suite, occur scattered throughout the Western Cape. The major occurrences located near Malmesbury and from Yzerfontein to Mud River on the West Coast were studied in detail using geochemical and isotopic techniques. Smaller outcrops at Philadelphia, Stellenbosch and Kuils River were also sampled and analyzed. The mafic and intermediate rocks are intrusive into tectonized Malmesbury metasediments. The pressure during crystallization of the Malmesbury intrusion is estimated at between 3 and 6 kb using an amphibole geobarometer. An extensive hydrothermal alteration event occured at the West Coast outcrops. This event occured at a pressure of 1.9 to 4.6 kb and a temperature ranging between 462 deg C and 532 deg C as determined by chlorite geothermometry and microthermometry. Most trace elements proved to be mobile during this event, whilst rare earth elements remained stable. Major mineral phases present in the igneous rocks include plagioclase, hornblende, augite, hypersthene and quartz, while alkali feldspar, zircon, sphene, pyrite, and magnetite are present in minor amounts. Minerals formed during the hydrothermal event are epidote, calcite, quartz, pyrite and jasper. Two geochemical trends were distinguished: a calcalkaline trend at Malmesbury and a subalkaline trend along the West Coast including Yzerfontein and Mud River. A monzonitic phase at Yzerfontein yielded a 519 (+ / -7) Ma zircon age. The caelded a 519 (+ / -7) Ma zircon age. The calcalkaline suite is expected to be older. The petrogenesis of this rock suite is complex. Repetitive intrusive events at depth explain much of the variation at Malmesbury and Yzerfontein. Fractional crystallization, remelting, magma mixing and magma mingling all contibuted to the rock-forming processes at Yzerfontein. The mafic and intermediate rocks as well as the Cape granites are interpreted as being intrusive into a subduction zone. This theory is supported by the structure of the Malmesbury metasediment host rock. 105 figs., 13 tabs., 71 refs

  9. Spatial Intrusion of Mining

    OpenAIRE

    SarathChand P.V.; Bhukya Shankar Nayak; Rambabu pemula; Nagamani K; Bhukya Ravindranaik,

    2011-01-01

    The Spatial Intrusion of Mining is a conceptual of space or the location component. The Mining can be viewed as the data about the objects which are located in physical space. It may be implemented by a specific location attributes by latitudes and longitudes and also by more implicitly included about the partitioning of the databases which are based on the location. The spatial data bases and ware houses were the data is accesses by by using the queries containing directions, adjacent and co...

  10. Distributed Intrusion Detection System

    Science.gov (United States)

    Internet worms and other malicious code often scan firewalls to determine which ports are unprotected. While firewall users have access to their port scanning data in the form of log files, most do not make use of it. The Distributed Intrusion Detection System remotely monitors trends in worldwide port scanning, and the data it has collected is available at this site. The data can be used by Internet professionals for early detection of worms or for implementing improved security measures. Firewall users can contribute to this project by downloading the free DShield Client, which automatically sends log reports for inclusion in worldwide data or by submitting logs online via a Web interface.

  11. Geochemical studies of granitic rocks of Kallur area, Manvi Taluk, Raichur district, Karnataka (India).

    Science.gov (United States)

    Raghavendra, N R; Reddy, R Purushottam; Nijagunappa, R

    2011-01-01

    The geochemical data is much widely used in establishing the overall chemical relation existing between the different rock types with their parentage. A major impetus for this shift comes not only from the need to understand and quantify better the spatial and temporal evolution, with emphasis on the younger greenstone belts (Kallur copper formations), but also from the recognition that such knowledge could form the basis for the sustainable development of our natural resources. In addition, the recurrence of natural hazards has reinforced the need to learn more about the mechanics and to develop predictive modeling with advanced technical tools. This paper is emphasizing on Granodiorites of Kallur area of Manvi Taluk, Raichur District to substantiate the classical approaches of exploration and data gathering through quantitative methods of data processing and interpretation. The trilinear diagram indicates that the granites are rich in Potash and Soda. This clearly indicates that Granites are fairly rich in K2O than Na2O. PMID:22324155

  12. Late-Archaean Potassic Granite from the Bundelkhand Craton, Central India

    Science.gov (United States)

    Sarkar, Saheli; Saha, Lopamudra; Nasipuri, Pritam; Pati, Jayanta Kumar; Patole, Vishal

    2014-05-01

    Late-Archaean granitoids, show wide range of compositional variation: (i) TTG like granitoids with strongly fractionated REE patterns, which can be both Na-rich and K-Mg-rich (Sanukitoids) (ii) K-rich, Mg-poor biotite granites with less fractionated REE patterns and showing negative Eu-anomalies (type area, the Closepet Granite, Eastern Dharwar Craton, India). Amongst them Late-Archaean Sanukitoid or K-rich Closepet-type granitoids are most widely reported from the Archaean Cratons world-wide: Superior Province, Canada, Pilbara Craton, Yilgarn Craton, Antarctica, Limpopo Belt, Dharwar Craton. Several models proposed so far for the origin of these granitoids mostly include partial melting of hydrated basalts, reaction of slab melts with mantle wedge peridotites, re-melting of an enriched mantle and then mixing of the resulting melt with the anatectic melt generated during the melting of continental crust in subduction zone settings. The Closepet-type potassic biotite-rich granites were mostly produced by re-melting of TTG-like continental basements most likely in a subduction zone setting. Most of the proposed models suggest such partial melting to have taken place in garnet-stability field and some in orthopyroxene-stability field. In this study we report late-Archaean (~2.61-2.5 Ga) potassic granite from the Bundelkhand Craton in central India. The Late-Archaean granitoids recorded from the craton are intrusive into the high-grade supracrustal rocks of the craton. They are classified as coarse grained grey, pink porphyritic granite, medium granied pink granite, granite porphyry and fine-grained pink granite. The supracrustal rocks of the craton have been metamorphosed at ~2.78 Ga under high-pressure conditions (~17-18 kbar)- medium temperature (600ºC) in a subduction zone setting. The intrusions of the granitoids at ~2.6-2.5 Ga mark the stability of the craton. The pink-porphyritic granite studied here preserves plagioclase-potash feldspar-orthopyroxene-muscovite-biotite-quartz. Plagioclase megacrysts mostly contain orthopyroxene inclusions and are rimmed by anti-perthite and potash feldspar. Biotite and muscovite mostly occur along the potash feldspar grain boundaries or along the grain fractures. The textural observations hence indicate that these granitic rocks are formed in two stages: (i) initial TTG-like melts formed by partial melting of pre-existing mafic supracrustal rocks in the orthopyroxene-stability field, as evidenced by orthopyroxene inclusions in the plagioclase megacrysts, followed by (ii) fractionation of plagioclase crystals, thus making the melt progressively enriched in potassium that led to rimming of the plagioclase megacrysts by anti-perthite or potash feldspar. Biotite and muscovite were formed during later retrogression due to fluid ingression. Whether such magma-forming processes were related to the ~2.78 Ga tectonics recorded from the craton or may be related to a short phase of collision tectonics post to that, needs further investigation.

  13. Two-mica granites of northeastern Nevada.

    Science.gov (United States)

    Lee, D.E.; Kistler, R.W.; Friedman, I.; Van Loenen, R. E.

    1981-01-01

    The field settings are described and analytical data are presented for six two-mica granites from NE Nevada. High delta 18O and 87Sr/86Sr values indicate that all are S-type granite, derived from continental crust. The major element chemistry and accessory mineral contents of these rocks also are characteristic of S-type granites. Chemical, X ray, and other data are presented for the micas recovered from these granites. The muscovites are notably high in Fe2O3, FeO, and MgO. Except for one hydrobiotite, each of the biotites has an MgO content near 6.0 wt%. Two different types of two-mica granites are recognized in the area of this study. One type is distinguished by the presence of many biotite euhedra within muscovite phenocrysts and by an unusual suite of accessory minerals completely devoid of opaque oxides. This type probably resulted from anatexis of late Precambrian argillites under conditions of relatively low oxygen fugacity, along a line that roughly coincides with the westward disappearance of continental basement. In the other textural type of two-mica granite the micas are equigranular and there is a greater variety of accessory minerals. The magmatic evolution of this type also appears to reflect the influence of late Precambrian argillites; there may be age differences between the two types of two-mica granites.-Author

  14. Lunar granites with unique ternary feldspars

    Science.gov (United States)

    Ryder, G.; Stoeser, D. B.; Marvin, U. B.; Bower, J. F.

    1975-01-01

    An unusually high concentration of granitic fragments, with textures ranging from holocrystalline to glassy, occurs throughout Boulder 1, a complex breccia of highland rocks from Apollo 17, Station 2. Among the minerals included in the granites are enigmatic K-Ca-rich feldspars that fall in the forbidden region of the ternary diagram. The great variability in chemistry and texture is probably the result of impact degradation and melting of a granitic source-rock. Studies of the breccia matrix suggest that this original granitic source-rock may have contained more pyroxenes and phosphates than most of the present clasts contain. Petrographic observations on Apollo 15 KREEP basalts indicate that granitic liquids may be produced by differentiation without immiscibility, and the association of the granites with KREEP-rich fragments in the boulder suggests that the granites represent a residual liquid from the plutonic fractional crystallization of a KREEP-rich magma. Boulder 1 is unique among Apollo 17 samples in its silica-KREEP-rich composition. We conclude that the boulder represents a source-rock unlike the bedrock of South Massif.

  15. Rapid deployment intrusion detection system

    International Nuclear Information System (INIS)

    A rapidly deployable security system is one that provides intrusion detection, assessment, communications, and annunciation capabilities; is easy to install and configure; can be rapidly deployed, and is reusable. A rapidly deployable intrusion detection system (RADIDS) has many potential applications within the DOE Complex: back-up protection for failed zones in a perimeter intrusion detection and assessment system, intrusion detection and assessment capabilities in temporary locations, protection of assets during Complex reconfiguration, and protection in hazardous locations, protection of assets during Complex reconfiguration, and protection in hazardous locations. Many DOE user-need documents have indicated an interest in a rapidly deployable intrusion detection system. The purpose of the RADIDS project is to design, develop, and implement such a system. 2 figs

  16. Modeling intrusions and correct recall in episodic memory : adult age differences in encoding of list context

    OpenAIRE

    Kliegl, Reinhold; Lindenberger, Ulman

    1993-01-01

    A model for correct recall and intrusions in cued recall of word lists is introduced. Intrusions are false responses that were correct in an earlier list. The model assumes 3 exclusive states for memory traces after encoding: with a list tag (i.e., with information about list origin), without list tags, and missing. Across lists, a trace can lose its list tag or its content. For retrieval, an optimal strategy of response selection was assumed. Younger and older laboratory-trained mnemonists p...

  17. Neutrons and Granite: Transport and Activation

    Energy Technology Data Exchange (ETDEWEB)

    Bedrossian, P J

    2004-04-13

    In typical ground materials, both energy deposition and radionuclide production by energetic neutrons vary with the incident particle energy in a non-monotonic way. We describe the overall balance of nuclear reactions involving neutrons impinging on granite to demonstrate these energy-dependencies. While granite is a useful surrogate for a broad range of soil and rock types, the incorporation of small amounts of water (hydrogen) does alter the balance of nuclear reactions.

  18. Passive intrusion detection system

    Science.gov (United States)

    Laue, E. G. (inventor)

    1980-01-01

    An intrusion detection system is described in which crystal oscillators are used to provide a frequency which varies as a function of fluctuations of a particular environmental property of the atmosphere, e.g., humidity, in the protected volume. The system is based on the discovery that the frequency of an oscillator whose crystal is humidity sensitive, varies at a frequency or rate which is within a known frequency band, due to the entry of an intruder into the protected volume. The variable frequency is converted into a voltage which is then filtered by a filtering arrangement which permits only voltage variations at frequencies within the known frequency band to activate an alarm, while inhibiting the alarm activation when the voltage frequency is below or above the known frequency band.

  19. Head and neck malignancies in younger patients

    International Nuclear Information System (INIS)

    We treated 23 (1.4% of all our primary cases) younger patients who are from 15 years old to 29 years old with head and neck malignancies at the Department of Head and Neck Surgery of the Miyagi Cancer Center Hospital for the past 12 years. There were 12 male and 11 female, and the sex ratio was approximately 1:1. There were 12 oral cancer patients, 6 epipharyngeal cancer patients and so on. There were 14 squamous cell carcinomas, 3 nasopharyngeal carcinomas and so on. 60% of all cases were squamous cell carcinomas. Clinically, advanced stage (stage III and IV) was diagnosed in 70% of patients at presentation. Although 19 patients had no past history, 2 patients had bronchial asthma, one had schizophrenia, and one had psychological disorder. Radical treatment was performed in 20 of 23 examples. The estimated Kaplan-Meier 5-year cause-specific survival rates for all patients were 76% and the 10-year cause-specific survival rates were 63%, respectively. It was thought that survival consequence was excellent in the whole. The problems of head and neck tumor treatment in a younger patient were thought about with late effect by radioactive rays and genital disorder by cancer chemotherapy. (author)

  20. Radiological implications of granite of northern Pakistan

    International Nuclear Information System (INIS)

    Granite is an igneous rock that contains natural radioactivity of primordial radionuclides. In Pakistan, granite is distributed in a vast area called the Ambela Granitic Complex (AGC) in North West Frontier Province (NWFP). Granite is a hard rock that exists in different colours and is used to decorate floors, kitchen counter tops, etc. The use of granite in a building as a decor material is a potential source of radiation dose; therefore, natural radioactivity has been measured in 20 granite samples of the AGC with an HPGe (high purity germanium) based gamma ray spectrometer. The average specific activities and their range (given in parentheses) for primordial radionuclides 40K, 226Ra and 232Th were 1218 (899-1927), 659 (46-6120) and 598 (92-3214) Bq kg-1, respectively. The measured activity concentrations were used for the assessment of hazard indices and radiation dose which were evaluated based on the permissible limits defined for these parameters. The measured specific activities and the derived quantities, hazard indices and radiation dose, have been compared with those given in the literature for these parameters

  1. Radiological implications of granite of northern Pakistan.

    Science.gov (United States)

    Asghar, M; Tufail, M; Sabiha-Javied; Abid, A; Waqas, M

    2008-09-01

    Granite is an igneous rock that contains natural radioactivity of primordial radionuclides. In Pakistan, granite is distributed in a vast area called the Ambela Granitic Complex (AGC) in North West Frontier Province (NWFP). Granite is a hard rock that exists in different colours and is used to decorate floors, kitchen counter tops, etc. The use of granite in a building as a decor material is a potential source of radiation dose; therefore, natural radioactivity has been measured in 20 granite samples of the AGC with an HPGe (high purity germanium) based gamma ray spectrometer. The average specific activities and their range (given in parentheses) for primordial radionuclides (40)K, (226)Ra and (232)Th were 1218 (899-1927), 659 (46-6120) and 598 (92-3214) Bq kg(-1), respectively. The measured activity concentrations were used for the assessment of hazard indices and radiation dose which were evaluated based on the permissible limits defined for these parameters. The measured specific activities and the derived quantities, hazard indices and radiation dose, have been compared with those given in the literature for these parameters. PMID:18714139

  2. Precambrian crustal evolution and Cretaceous–Palaeogene faulting in West Greenland: Pre-Nagssugtoqidian crustal evolution in West Greenland: geology, geochemistry and deformation of supracrustal and granitic rocks north-east of Kangaatsiaq

    Directory of Open Access Journals (Sweden)

    Watt, Gordon R.

    2006-12-01

    Full Text Available The area north-east of Kangaatsiaq features polyphase grey orthogneisses, supracrustal rocks and Kangaatsiaq granite exposed within a WSW–ENE-trending synform. The supracrustal rocks are comprised of garnet-bearing metapelites, layered amphibolites and layered, likewise grey biotite paragneisses. Their association and geochemical compositions are consistent with a metamorphosed volcano-sedimentary basin (containing both tholeiitic and calc-alkali lavas and is similar to other Archaean greenstone belts. The Kangaatsiaq granite forms a 15 × 3 km flat, subconcordant body of deformed,pink, porphyritic granite occupying the core of the supracrustal synform, and is demonstrably intrusive into the amphibolites. The granite displays a pronounced linear fabric (L or L > S. Thepost-granite deformation developed under lower amphibolite facies conditions (400 ± 50°C, and is characterised by a regular, NE–SW-trending subhorizontal lineation and an associated irregular foliation, whose poles define a great circle; together they are indicative of highly constrictional strain. The existence of a pre-granite event is attested by early isoclinal folds and a foliation within the amphibolites that is not present in the granite, and by the fact that the granite cuts earlier structures in the supracrustal rocks. This early event, preserved only in quartz-free lithologies, resulted in high-temperature fabrics being developed under upper amphibolite to granulite facies conditions.

  3. Shrimp U-Pb age and Sr-Nd isotopes of the Morro do Baú mafic intrusion: implications for the evolution of the Arenópolis volcano-sedimentary sequence, Goiás Magmatic Arc

    OpenAIRE

    Pimentel, Ma?rcio M.; Hollanda, Maria Helena B. M.; Richard Armstrong

    2003-01-01

    The Arenópolis volcano-sedimentary sequence is located in the southern part of the Goiás Magmatic Arc and includes a ca. 900 Ma calc-alkaline arc sequence made of volcanic rocks ranging in composition from basalts to rhyolites, metamorphosed under greenschist to amphibolite facies. Small calc-alkaline gabbro to granite sub-volcanic bodies are also recognized. The Morro do Baú intrusion is the largest of these intrusions, and is made of gabbros and diorites. Zircon grains separated from one...

  4. Monazite-(Ce in Hercynian granites and pegmatites of the Bratislava massif, Western Carpathians: compositional variations and Th-U-Pb electron-microprobe dating

    Directory of Open Access Journals (Sweden)

    Pavel Uher

    2014-12-01

    Full Text Available Monazite-(Ce represents a characteristic magmatic accessory mineral of the Hercynian peraluminous S-type granites to granodiorites and related granitic pegmatites of the Bratislava Granitic Massif (BGM, Malé Karpaty Mountains, Central Western Carpathians, SW Slovakia. Monazite forms euhedral to subhedral crystals, up to 200 ?m in size, usually it is unzoned in BSE, rarely it reveals oscillatory or sector zoning. Thorium concentrations of 2 to 9 wt. % ThO2 (?0.09 apfu and local elevated uranium contents (?4.3 wt. % UO2, ?0.04 apfu are characteristic for the pegmatite monazites. Both huttonite ThSiREE-1P-1 and cheralite Ca(Th,UREE-2 substitutions took place in the studied monazite. Electron-microprobe Th-U-Pb monazite dating of the granites and pegmatites gave an isochron age of 353±2 Ma (MSWD = 0.88, n = 290, which confirmed the meso-Hercynian, Carboniferous, Lower Mississipian magmatic crystallization. An analogous age (359±11 Ma was obtained from monazite from adjacent paragneiss, corresponding to the age of the Hercynian contact thermal metamorphism related to the granite intrusion of BGM. Monazite in some granite shows also older clastic or authigenic grains or zones (~505 to 400 Ma, with maximum of 420±7 Ma which probably represents inherited material from the Lower Paleozoic metapelitic to metapsammitic protolith of BGM.

  5. Relationships Between Shearing and Granitic Magma Emplacement: the Remígio-Pocinhos Shear Zone in the São José do Campestre Massif, NE Brazil

    Directory of Open Access Journals (Sweden)

    Rielva Solimairy Campelo do Nascimento

    2010-10-01

    Full Text Available Based on mineralogical, geochemical and textural characteristics, a variety of granite types was identified amongstthe intrusions emplaced during the tectonic activity along the Remígio-Pocinhos shear zone in NE Brazil during the lateststages of the Brasiliano orogeny. They include peraluminous granites with I-type mineralogical compositions as well astransitional-to-alkaline geochemical characteristics. These granites contain mafic to intermediate microgranular enclaves.Overall, they are very similar to many other Brasiliano-age plutons in the extreme NE of Brazil. Metaluminous alkalinegranites with aegirine-augite usually contain andradite as a minor phase, and titanite as an important accessory mineral.Several aspects of their trace element geochemistry repeat features of syn to late- tectonic alkaline granites in other parts ofNE Brazil and in the rest of the world. The shear zone has deep roots, and the heat flow during granite genesis was probablyhigh. A variety of lower crustal source rocks was probably involved in the genesis of these granites.

  6. Mineralogy, chemistry, and age of granitic veins at Nicholson's Point, South Coast, Natal

    International Nuclear Information System (INIS)

    Undeformed granitic veins exposed at Nicholson's Point, southern Natal, intrude nearly all the foliated rock types between Drakes Beach and Leisure Bay and therefore appear to post-date the major deformation episodes. The veins define an en echelon array and appear to have been emplaced syn-tectonically to post-tectonically. In addition to quartz and feldspar, the veins are characterized by variable ferro magnesian minerals, namely, tourmaline, magnetite, dumortierite, and biotite. A Rb/Sr isotope study yields a date of 960 ± 32 Ma which is within error of the date of the nearby deformed Glenmore Granite. These results imply that much of the deformation history recorded in the southern sector of Natal Structural and Metamorphic Province either occurred within a relatively short period or that the age of the Glenmore Granite is a reset age. The veins represent one of the youngest events recognized in the tectonic and intrusive history of the Natal Structural and Metamorphic Province. 18 refs., 7 figs., 5 tabs

  7. Age, composition, and source of continental arc- and syn-collision granites of the Neoproterozoic Sergipano Belt, Southern Borborema Province, Brazil

    Science.gov (United States)

    Oliveira, Elson P.; Bueno, Juliana F.; McNaughton, Neal J.; Silva Filho, Adejardo F.; Nascimento, Rosemery S.; Donatti-Filho, José P.

    2015-03-01

    The Sergipano belt is the outcome of collision between the Pernambuco-Alagoas Domain (Massif) and the São Francisco Craton during Neoproterozoic assembly of West Gondwana. Although the understanding of the Sergipano belt evolution has improved significantly, the timing of emplacement, geochemistry and tectonic setting of granitic bodies in the belt is poorly known. We recognized two granite age groups: 630-618 Ma granites in the Canindé, Poço Redondo and Macururé domains, and 590-570 Ma granites in the Macururé metasedimentary domain. U-Pb SHRIMP zircon ages for granites of first age group indicated ages of 631 ± 4 Ma for the Sítios Novos granite, 623 ± 7 Ma for the Poço Redondo granite, 619 ± 3.3 Ma for the Lajedinho monzodiorite, and 618 ± 3 Ma for the Queimada Grande granodiorite. These granitoids are dominantly high-K calc-alkaline, magnesian, metaluminous, mafic enclave-rich (Queimada Grande and Lajedinho), or with abundant inherited zircon grains (Poço Redondo and Sitios Novos). Geochemical and isotope data allow us to propose that Sítios Novos and Poço Redondo granites are product of partial melting of Poço Redondo migmatites. Sr-Nd isotopes of the Queimada Grande granodiorite and Lajedinho monzodiorite suggest that their parental magma may have originated by mixing between a juvenile mafic source and a crustal component that could be the Poço Redondo migmatites or the Macururé metasediments. Other 630-618 Ma granites in the belt are the mafic enclave-rich Coronel João Sá granodiorite and the Camará tonalite in the Macururé sedimentary domain. These granites have similar geochemical and isotopic characteristics as the Lajedinho and Queimada Grande granitoids. We infer for the Camará tonalite and Coronel João Sá granodiorite that their parental magmas have had contributions from mafic lower crust and felsic upper crust, most probably from underthrust São Francisco Craton, or Pernambuco-Alagoas Domain. The younger 590-570 Ma granite group is confined to the Macururé metasedimentary domain. Although these granites do not show typical features of S-type granites, their U-Pb age, field relationships, geochemical and Sr-Nd data suggest that their parental magmas have originated from high degree melting of the Macururé micaschists. Field observations support a model in which the Macururé domain, limited by the Belo Monte-Jeremoabo and São Miguel do Aleixo shear zones, behaved as a ductile channel flow for magma migration and emplacement during the Neoproterozoic, very much like the channel flow model proposed for emplacement of leucogranites in the Himalayas.

  8. Novel Approach for Hybrid Intrusion Detection System

    OpenAIRE

    Ravi Kishore Sharma, Mr. Gajendra Singh Chandel

    2012-01-01

    This Paper titled “Novel Approach for Intrusion Detection System” is an intrusion detection system (IDS) proposed by analyzing the principle of the intrusion detection system based on host and network. Basically this paper is to develop host based cum network based intrusion detection system for Microsoft Windows XP environment. Proposed concept that had used in this was applying intrusion detection rule matching technique on the Security Log File and Event Log File in Microsoft Windows X...

  9. Two contrasting granite types: 25 years later

    International Nuclear Information System (INIS)

    The concept of I- and S-type granites was introduced in 1974 to account for the observation that, apart from the most felsic rocks, the granites in the Lachlan Fold Belt have properties that generally fall into two distinct groups. This has been interpreted to result from derivation by partial melting of two kinds of source rocks, namely sedimentary and older igneous rocks. The original publication on these two granite types is reprinted and reviewed in the light of 25 years of continuing study into these granites. Data on oxygen isotopic compositions of the two granite types were not available in 1974. O'Neil and Chappell (1977) found differences in such composition between the I- and S-type granites of the Berridale Batholith, with the two types having ?18O values less than and greater than 10%o, respectively, relative to SMOW This division is supported by our additional unpublished data on granites from other parts of the Lachlan Fold Belt, but needs to be tested further. Chappell and White (1974) noted that the initial 87Sr/86Sr values for a single S-type pluton are more variable than for I-type plutons, interpreted to reflect the more heterogeneous nature of the source material. That observation has been confirmed by later observations. The heterogeneity of isotopic compositions of S-type plutons is illustrated by the Jillamatong Granodiorite of the Kosciuszko Batholith. For that single unit, the range in 87Sr/8687Sr/86Sr calculated at 430 Ma is from 0.71115 to 0.71541. Copyright (2001) Geological Society of Australia

  10. Rare metal granites and related rocks of the Ukrainian shield

    Directory of Open Access Journals (Sweden)

    Esipchuk, K.Ye.

    1993-12-01

    Full Text Available Two rare metal leucocratic granites, Perga and Kamennaya complexes, can be distinquished on the Ukrainian shield. The Perga complex consists of medium- and coarse grained, mainly porphyric, biotite, riebeckite and aegirine granites, granite porphyries, microclinites and albitites with rare metal mineralization (genthelvite, phenacite, tantalite, cassiterite and wolframite etc.. Granites from several stocks (up to 30 km2 in the northwestern part of the shield, situated along the fracture zone, restricted the large Korosten pluton of rapakivi granites to the northwest. The age of these granites (Pb-Pb and U-Pb methods on zircon and monazite practically coincide with the age of rapakivi granites being 1750 Ma. Within the Korosten complex of rapakivi granites we consider that zinnwaldite granites, which are characterized by fluorite and topazine mineralization, represent the final phase of pluton. These granites differ from the Perga ones by their low content of rare metals. The Kamennaya Mogila complex lies in the southeastern part of the Ukrainian shield. It consists of biotite and muscovite-biotite, medium- and coarse-grained (also porphyric, and occasionally greisining granites with rare metal mineralization (cassiterite, columbite, molybdenite, wolframite and beryl. Granites form several stocks (5-30 km2 situated 10-30 km to the west-northwest of the South-Kalchik gabbro-syenite-granite pluton. Granitoids in both of these complexes have similar isotopic ages (1800 Ma. Leucocratic subalkaline granites (the Novoyanisol type are known within the pluton itself, occupying an intermediate position between the above mentioned in terms of mineral and geochemical composition. The gabbro-syenite-granite formation of the Nearazov region has a substantial similarity to the anorthosite-rapakivi-granite formation. In this respect the relation of each of them to rare metal granites is rather remarkable. This relation is, most probably, not only spatial, but also genetic. The typical rare metal granites are situated not in the parent plutons but at some distance from them.

  11. Sorption behaviour of granite for radionuclides in groundwater condition

    International Nuclear Information System (INIS)

    The sorption behavior of granite for Cs and Nd in the underground water condition was investigated as the function of mineralogical alteration of granite and particle size. The physicochemical characterization of the granite samples was carried out in terms of mineral phase, pore structure and elements eluted by soft acid treatment as the function of alteration of the granite. The increase of porosity of granite, and phase change of biotite and plagioclase into chlorite and illite, respectively were observed with the increase of alteration degree. The sorption capacities of the series of granites slightly increased with the increase of alteration degree. (authors)

  12. Radiometric analysis of Chinese commercial granites

    International Nuclear Information System (INIS)

    Due to the widespread use of granites as building and ornamental materials, measurements of 226Ra, 232Th and 40K activities in commercial granites have been carried out using a NaI(Tl) ?-ray spectrometer with a matrix-inversion-based spectral stripping technique. The concentrations of 226Ra, 232Th and 40K in Chinese commercial granite range from 14.5 to 204.7 Bq x kg-1, 16.7 to 186.7 Bq x kg-1 and 185.7 to 1745.6 Bq x kg-1, respectively. The mean values of the activity concentrations of 226Ra, 232Th and 40K in red and pink commercial granites are all higher than those in black and gray commercial ones. The radium equivalent activity (Raeq), the external hazard index (Hex), the internal hazard index (Hin ) and the annual gonadal dose equivalent (AGDE) were also calculated and compared to the international recommended values. Six types of red commercial granites (CBR, MLR, QXR, PBR, JXR, LQR, YDR and TSR) of China do not satisfy the universal standards. (author)

  13. Analysis of the Younger Dryas Impact Layer

    Energy Technology Data Exchange (ETDEWEB)

    Firestone, Richard B.; West, Allen; Revay, Zsolt; Hagstrum, Jonathon T,; Belgya, Thomas; Hee, Shane S. Que; Smith, Alan R.

    2010-02-27

    We have uncovered a thin layer of magnetic grains and microspherules, carbon spherules, and glass-like carbon at nine sites across North America, a site in Belgium, and throughout the rims of 16 Carolina Bays. It is consistent with the ejecta layer from an impact event and has been dated to 12.9 ka BP coinciding with the onset of Younger Dryas (YD) cooling and widespread megafaunal extinctions in North America. At many locations the impact layer is directly below a black mat marking the sudden disappearance of the megafauna and Clovis people. The distribution pattern of the Younger Dryas boundary (YDB) ejecta layer is consistent with an impact near the Great Lakes that deposited terrestrial-like ejecta near the impact site and unusual, titanium-rich projectile-like ejecta further away. High water content associated with the ejecta, up to 28 at. percent hydrogen (H), suggests the impact occurred over the Laurentide Ice Sheet. YDB microspherules and magnetic grains are highly enriched in TiO{sub 2}. Magnetic grains from several sites are enriched in iridium (Ir), up to 117 ppb. The TiO{sub 2}/FeO, K/Th, TiO{sub 2}/Zr, Al{sub 2}O{sub 3}/FeO+MgO, CaO/Al{sub 2}O{sub 3}, REE/ chondrite, FeO/MnO ratios and SiO{sub 2}, Na{sub 2}O, K{sub 2}O, Cr{sub 2}O{sub 3}, Ni, Co, U, Th and other trace element abundances are inconsistent with all terrestrial and extraterrestrial (ET) sources except for KREEP, a lunar igneous rock rich in potassium (K), rare-earth elements (REE), phosphorus (P), and other incompatible elements including U and Th. Normal Fe, Ti, and {sup 238}U/{sup 235}U isotopic abundances were found in the magnetic grains, but {sup 234}U was enriched over equilibrium values by 50 percent in Murray Springs and by 130 percent in Belgium. 40K abundance is enriched by up to 100 percent in YDB sediments and Clovis chert artifacts. Highly vesicular carbon spherules containing nanodiamonds, glass-like carbon, charcoal and soot found in large quantities in the YDB layer are consistent with an impact followed by intense burning. Four holes in the Great Lakes, some deeper than Death Valley, are proposed as possible craters produced by the airburst breakup of a loosely aggregated projectile.

  14. Regional S-type granites in the Ecuadorian Andes: Possible remnants of the breakup of western Gondwana

    Science.gov (United States)

    Aspden, J. A.; Fortey, N.; Litherland, M.; Viteri, F.; Harrison, S. M.

    1992-10-01

    Reconnaissance geological mapping of the Ecuadorian Cordillera Real has established the presence of a previously unrecognized regional suite of variably deformed granitoids for which poorly constrained Rb?Sr whole-rock data indicate a minimum Early Jurassic age of 200 ± 12 Ma (initial ratio = 0.7120). This suite, which is associated with low- to medium-grade, semipelitic metamorphic rocks, is dominated by peraluminous monzogranites containing biotite ± garnet ± muscovite. Geochemically, these granites are S-types and can be readily distinguished from juxtaposed I-type granitoids of the Middle-Upper Jurassic Zamora, Abitagua, and Azafrán batholiths located immediately to the east. Intrusion of these S-type granites may be related to the breakup of western Gondwana.

  15. Archean and paleoproterozoic granitoids and crustal evolution of the Rio Maria granite-greenstone terrane, Eastern Amazonian craton Brazil

    International Nuclear Information System (INIS)

    The Rio Maria Granite-Greenstone Terrane (RMGGT) is situated in the Caraj Province, which is the most important Archean domain of the Amazonian craton (Machado et al., 1991; Macambira and Lafon, 1995; Tassinari and Macambira, 1999; Santos et al., 2000; Dall'Agnol et al., 2000). Several Archean granitoid suites and supracrustal sequences have been described in the RMGGT (Dall'Agnol et al., 1997; Althoff et al., 2000; Souza et al., 2001). Geochemical and isotopic data are now available allowing a better evaluation of the crustal evolution of this terrane. Paleoproterozoic, A-type oxidized granites (Dall'Agnol et al., 1999a) are intrusive in the Archean rocks of the RMGGT and their evolution will also be discussed (au)

  16. Retention of Anionic Species on Granite: Influence of Granite Composition - 12129

    International Nuclear Information System (INIS)

    Technetium (Tc-99, T1/2 = 2.1.105 yrs) and selenium (Se-79, T1/2 = 6.5.104 yrs) belong among fission products, being produced by fission of nuclear fuel. Both elements can significantly contribute to risk due to their complicated chemistry, long life times, high mobility and prevailing anionic character. Therefore, knowledge of migration behaviour under different conditions can significantly improve input into performance and safety assessment models. Granite is considered as a potential host rock for deep geological disposal of radioactive waste in many countries. Granitic rocks consist usually of quartz, feldspar, plagioclase (main components), mica, chlorite, kaolinite (minor components). The main feature of the rock is advection governed transport in fractures, complemented with diffusion process from fracture towards undisturbed rock matrix. The presented work is focused on interaction of anionic species (TcO4-, SeO42-, SeO32-) with granitic rock. Furthermore, the importance of mineral composition on sorption of anionic species was also studied. The batch sorption experiments were conducted on the crushed granite from Bohemian Massive. Five fractions with defined grain size were used for static batch method. Mineral composition of each granitic fraction was evaluated using X-ray diffraction. The results showed differences in composition of granitic fractions, even though originating from one homogenized material. Sorption experiments showed influence of granite composition on adsorption of both TcO4- and SeO32- on granitic rock. Generally, Se(IV) showed higher retention than Tc(VII). Se(VI) was not almost sorbed at all. Fe containing minerals are pronounced as a selective Se and Tc sorbent, being reduced on their surface. As micas in granite are usually enriched in Fe, increased sorption of anionic species onto mica enriched fractions can be explained by this reason. On the other hand, fractions enriched in feldspar did not show increased sorption affinity to Tc and Se. (authors)

  17. Petrogenesis of the early Paleozoic strongly peraluminous granites in the Western South China Block and its tectonic implications

    Science.gov (United States)

    Peng, Touping; Fan, Weiming; Zhao, Guochun; Peng, Bingxia; Xia, Xiaoping; Mao, Yongsheng

    2015-02-01

    Strongly peraluminous (SP) granites have A/CNK (molecular Al2O3/(CaO+Na2O+K2O)) ratios >1.1, indicating a predominant origin from the partial melting of metasedimentary rocks. However, an increasing number of studies have documented that mantle-derived magmas can also be involved in the petrogenesis of some SP granites. This is the case in the Dulong batholith in the southeastern Yunnan province, southwestern South China Block, which is typically composed of SP granitic rocks with high A/CNK values (>1.1). Zircon U-Pb dating of four samples from this batholith yielded consistent crystallization ages of ca. 430 Ma, synchronous with the widespread late-orogenic magmatism (including S- and I-type granites and mafic igneous rocks) in the Wuyi-Yunkai orogen, South China Block (SCB). All the granites have fractionated REE patterns ((La/Yb)N = 1.28-12.3) and conspicuous negative Eu anomalies (Eu?/Eu = 0.07-0.43) with a similar depletion in HFSE (Nb, Zr, Hf), P, Ba and Sr, suggesting that these granitic magmas had a dominantly crustal source, likely the Neoproterozoic metasedimentary rocks (i.e., the Danzhou or Banxi groups) that are dominated by pelitic rocks with minor interlayered siltstones in the western Yangtze Block. However, their zircon Hf isotopic results also reveal an important input of the mantle-derived melts into their parental magma. Taken together, their geochemical and isotopic compositions reflect a derivation by magma mixing between the crust- and mantle-derived (?10% in volume) magmas. Their chemical variations resulted from the fractionation process during the emplacement from the magma chamber after magmatic mixing. In conjunction with regional data within the SCB, it is most likely that the magmatism younger than 435 Ma was generated in a post-collisional extensional regime related to the partial delamination of an overthickened lithospheric mantle root without lower crust.

  18. Radioactivity and Geochemistry of Jasperoid Veins in Gabal Al-AGLAB Granitic Pluton, North Eastern Desert, Egypt

    International Nuclear Information System (INIS)

    Al-Aglab granitic pluton hosts jasperoid as vein type mineralization. This mineralization are structurally controlled by faults and their feather joints, which are associated with NE-SW to ENE- WSW joints and micro-fractures,widespread silicification, and to a lesser extent kaolinitization and sericitization as well as other alterations accompanying the uranium mineralization. Petrologically, the studied younger granites are classified as syenogranites and texturally asperthitic leucogranites. They are originated from per aluminous, calc-alkaline, highly fractionated magma. The studied granites showed higher U and Th contents and lower Th/U ratios than those of the normal granites. They are considered as uraniferous granites originated from highly fractionated U rich magma with trapping high concentrations of uranium in the higher quotient of the radioactive accessory minerals (e.g. zircon, apatite and sphene). Uranium is concentrated at the central parts of the jasperoid veins, following the NE trend and dipping SE direction, due to their intersection with the WNW sinistral fault. Some of the anomalies are associated with visible secondary uranium minerals mainly uranophane and beta-uranophane. The high levels of radioactivity are mainly due to the high U and Th contents in jasperoid veins and the uranium content reached to 843 ppm and thorium 206 ppm. Gabal Al-Aglab uranium occurrence is considered as an example for a simple uranium vein type mineralization. It is c uranium vein type mineralization. It is closely associated with and restricted to the younger granite itself that affected by hydrothermal alteration. The uranium bearing late magmatic fluids could be derived from the same magma that originates the granitic pluton itself at the late stage of the magmatic activity. Geochemically, XRF and ESEM (environmental scanning electron microscope) analyses showed that Gabal Al-Aglab jasperoid veins were enriched in Th, U, Zr, W and LREE (Ce and La). The separated heavy fractions of jasperoid veins showed the presence of alunogen Al2(SO4)3.17H2O and pahasapite (Ca, Li) 11 Li 8Be 24(PO4)24.38H2O

  19. Iron content and reducing capacity of granites and bentonite

    International Nuclear Information System (INIS)

    The iron contents in various granites and in bentonite have been determined. For granites, the content is usually in the range 1-9% (weight) and 2.5-3% for bentonite. Most of the iron is divalent in the granites (70-90%); in bentonite the divalent fraction is 25-50%. A large part of the divalent iron in the granites appears to be accessible for the reduction of dissolved oxygen in an aqueous system. (author)

  20. Fluid inclusion planes and paleofluid records in the Podlesí granite, Krušné hory Mts., Czech Republic

    Directory of Open Access Journals (Sweden)

    Dobeš P

    2005-06-01

    Full Text Available Three generations of fluid inclusion planes (FIP were distinguished in rocks of the PTP-3 borehole from the Podlesí granite stock (Krušné hory Mts.. The oldest generation of FIP is believed to have followed the propagation of proto-tectonic subhorizontal aplite dykes and steep veinlets of greisen mineralization, at temperatures of about 400 °C and pressures less than 100 MPa. The later FIP contain fluid inclusions with homogenization temperatures from 140 to 270 °C, and likely represent hydrothermal fluids associated with the repeated opening of fractures during the late stages of intrusive complex development.

  1. SHRIMP zircon U-Pb dating of the mafic and felsic intrusive rocks of the Saza area in the Lupa goldfields, southwestern Tanzania: Implication for gold mineralization

    OpenAIRE

    Shukrani Manya

    2012-01-01

    The Lupa Goldfield (LGF) is one of the eight structural terranes in the NW – SE striking Ubendian Belt of SW Tanzania. The LGF is comprised of granitic gneisses with bands of amphibolites which are intruded by mafic intrusions including gabbros, granodiorites, diorites; and various granites as well as metavol-canics. These rocks are cross-cut by narrow mafic dykes and aplites. SHRIMP zircon U-Pb data are presented for the granodiorite and a mafic dyke that cross-cut the granodiorites in the...

  2. Zircon geochronology of Berach granite of Chittorgarh, Rajasthan

    International Nuclear Information System (INIS)

    Discordant ages of zircons from Berach granite suggest that this granite crystallized around 2610 m.y. ago and lost lead during an episodic event around 710 m.y. The 710 m.y. date probably reflects a response to a regional thermal event also recorded in the 730 m.y. zircon age for the Mt. Abu 'Erinpura type' granite. (author)

  3. Ilmenit z dvojslídných granit? klenovského plutonu.

    Czech Academy of Sciences Publication Activity Database

    René, Miloš

    2013-01-01

    Ro?. 46, Prosinec (2013), s. 224-227. ISSN 0514-8057 R&D Projects: GA MŠk ME10083 Institutional support: RVO:67985891 Keywords : ilmenite * two-mica granite * Moldanubian Zone * Bohemian Massif Subject RIV: DB - Geology ; Mineralogy http://www.geology.cz/zpravy/obsah/2012/Zpravy_2012-45.pdf

  4. DOE Intrusion Detection Systems Handbook

    International Nuclear Information System (INIS)

    The article reviews the Intrusion Detection Systems Handbook that was prepared by Sandia Laboratories for the U.S. Department of Energy, Office of Safeguards and Security. The purpose of the handbook is to provide information pertinent to the selection, procurement, installation, testing, and maintenance of the elements of an intrusion detection system. These elements include interior and exterior sensors, alarm assessment equipment, and alarm reporting equipment. The handbook also contains a discussion of how these elements can be integrated into an operationally effective system

  5. The geology and petrogenesis of the southern closepet granite

    Science.gov (United States)

    Jayananda, M.; Mahabaleswar, B.; Oak, K. A.; Friend, C. R. L.

    1988-01-01

    The Archaean Closepet Granite is a polyphase body intruding the Peninsular Gneiss Complex and the associated supracrustal rocks. The granite out-crop runs for nearly 500 km with an approximate width of 20 to 25 km and cut across the regional metamorphic structure passing from granulite facies in the South and green schist facies in the north. In the amphibolite-granulite facies transition zone the granite is intimately mixed with migmatites and charnockite. Field observations suggests that anatexis of Peninsular gneisses led to the formation of granite melt, and there is a space relationship between migmatite formation, charnockite development and production and emplacement of granite magma. Based on texture and cross cutting relationships four major granite phases are recognized: (1) Pyroxene bearing dark grey granite; (2) Porphyritec granite; (3) Equigranular grey granite; and (4) Equigranular pink granite. The granite is medium to coarse grained and exhibit hypidiomorphic granular to porphyritic texture. The modal composition varies from granite granodiorite to quartz monzonite. Geochemical variation of the granite suite is consistent with either fractional crystallization or partial melting, but in both the cases biotite plus feldspar must be involved as fractionating or residual phases during melting to account trace element chemistry. The trace element data has been plotted on discriminant diagrams, where majority of samples plot in volcanic arc and within plate, tectonic environments. The granite show distinct REE patterns with variable total REE content. The REE patterns and overall abundances suggests that the granite suite represents a product of partial melting of crustal source in which fractional crystallization operated in a limited number of cases.

  6. VISUALIZATION TECHNIQUES FOR INTRUSION DETECTION – A SURVEY

    OpenAIRE

    Ibrahim Elhenawy; Alaa El - Din Riad; Ahmed Hassan; Nancy Awadallah

    2011-01-01

    In traditional intrusion detection system (IDS) environments, little activity has been applied to usingvisual analysis as an aid to intrusion detection. With more information systems being attacked and attacktechniques evolving, the task of detecting intrusions is becoming an increasingly difficult. Efficientinformation visualization is an important element required for urgent detection of intruders.This paper presents a survey on using visualization techniques in intrusion detection system.F...

  7. STATISTICAL TECHNIQUES IN ANOMALY INTRUSION DETECTION SYSTEM

    OpenAIRE

    Hari Om; Tanmoy Hazra

    2012-01-01

    In this paper, we analyze an anomaly based intrusion detection system (IDS) for outlier detection in hardware profile using statistical techniques: Chi-square distribution, Gaussian mixture distribution and Principal component analysis. Anomaly detection based methods can detect new intrusions but they suffer from false alarms. Host based Intrusion Detection Systems (HIDSs) use anomaly detection to identify malicious attacks i.e. intrusion. The features are shown by large set of dimensions an...

  8. Composite Intrusion Detection in Process Control Networks

    OpenAIRE

    Rrushi, Julian

    2009-01-01

    An intrusion detection ensemble, i.e. a set of diverse intrusion detection algorithms employed as a group, has been shown to outperform each one those diverse algorithms employed individually. Moving along this line, we have devised an intrusion detection ensemble that inspects network packets that flow across the process control network of a digitally controlled physical system such as a power plant. Such process control specific intrusion detection ensemble is comprised of a statistical ano...

  9. Fractal patterns of fractures in granites

    Science.gov (United States)

    Velde, B.; Dubois, J.; Moore, D.; Touchard, G.

    1991-01-01

    Fractal measurements using the Cantor's dust method in a linear one-dimensional analysis mode were made on the fracture patterns revealed on two-dimensional, planar surfaces in four granites. This method allows one to conclude that: 1. (1)|The fracture systems seen on two-dimensional surfaces in granites are consistent with the part of fractal theory that predicts a repetition of patterns on different scales of observation, self similarity. Fractal analysis gives essentially the same values of D on the scale of kilometres, metres and centimetres (five orders of magnitude) using mapped, surface fracture patterns in a Sierra Nevada granite batholith (Mt. Abbot quadrangle, Calif.). 2. (2)|Fractures show the same fractal values at different depths in a given batholith. Mapped fractures (main stage ore veins) at three mining levels (over a 700 m depth interval) of the Boulder batholith, Butte, Mont. show the same fractal values although the fracture disposition appears to be different at different levels. 3. (3)|Different sets of fracture planes in a granite batholith, Central France, and in experimental deformation can have different fractal values. In these examples shear and tension modes have the same fractal values while compressional fractures follow a different fractal mode of failure. The composite fracture patterns are also fractal but with a different, median, fractal value compared to the individual values for the fracture plane sets. These observations indicate that the fractal method can possibly be used to distinguish fractures of different origins in a complex system. It is concluded that granites fracture in a fractal manner which can be followed at many scales. It appears that fracture planes of different origins can be characterized using linear fractal analysis. ?? 1991.

  10. The pre-Malmesbury granitic basement in the Franschhoek Valley

    International Nuclear Information System (INIS)

    A revision of the previously accepted stratigraphic models of the Franschhoek valley based on new geochronological and mineralogical data is presented. The Franschhoek quartz-porphyry dykes represent a phase of the Cape Granite Suite and as they cut the Franschhoek Formation the latter must be regarded as part of the Malmesbury Group. The two granites exposed at the eastern end of the Franschhoek valley have different ages; the Assegaaibos Granite belongs to the Cape Granite Suite (slightly older than the Franschhoek quartz-porphyry dykes), but the Keerwedernek Granite pre-dates the Franschhoek Formation and must therefore represent the pre-Malmesbury basement

  11. Emotional and Behavioral Reaction to Intrusive Thoughts

    Science.gov (United States)

    Berry, Lisa-Marie; May, Jon; Andrade, Jackie; Kavanagh, David

    2010-01-01

    A self-report measure of the emotional and behavioral reactions to intrusive thoughts was developed. The article presents data that confirm the stability, reliability, and validity of the new seven-item measure. Emotional and behavioral reactions to intrusions emerged as separate factors on the Emotional and Behavioral Reactions to Intrusions

  12. He, Pb and S isotopic constraints on the relationship between the A-type Qitianling granite and the Furong tin deposit, Hunan Province, China

    Science.gov (United States)

    Li, Zhao-li; Hu, Rui-zhong; Yang, Jing-sui; Peng, Jian-tang; Li, Xiao-min; Bi, Xian-wu

    2007-08-01

    The Furong tin deposit, located in southern Hunan Province, China, is a large, newly discovered deposit with an estimated Sn reserve of about 700,000 tons. The deposit is spatially and temporally associated with the A-type Qitianling granite. The 3He/ 4He ratios of fluid inclusions trapped in sulfides from the deposit range from 0.13 to 2.95 Ra, indicating a mixed crust-mantle source, similar to that of the Qitianling granite complex. Lead isotopes in feldspars of the granite (mostly in the range of 206Pb/ 204Pb = 18.547-19.180, 207Pb/ 204Pb = 15.598-15.825, 208Pb/ 204Pb = 37.912-39.068) and in sulfide minerals ( 206Pb/ 204Pb = 18.467-18.836, 207Pb/ 204Pb = 15.503-15.772, 208Pb/ 204Pb = 38.607-39.099) are essentially the same, indicating that the lead in both was derived mainly from the upper crust, with a small mantle component. The sulfur isotopic values of the ore minerals vary widely, ranging from - 26.1‰ to + 10.4‰, but are mainly within the range of + 0.2‰ to + 10.4‰, implying that the S in the hydrothermal fluids was derived mainly from magmatic fluids, with minor contributions from the mantle, sedimentary rocks and biogenic material. The He, Pb and S isotopes all confirm that the ore-forming fluids of the Furong deposit were magmatic in origin, derived from the melts that produced the Qitianling A-type granite. The tin mineralization occurs within, or along the margins of, the Qitianling granite complex, and the timing of the mineralization coincides with the intrusive age of the granite. The available data suggest that the emplacement of the granites and the mineralization was related to mantle upwelling and extension of the lithosphere in South China during the Mesozoic.

  13. Geoquímica e geocronologia U-Pb (SHRIMP) de granitos da região de Peixoto de Azevedo: Província Aurífera Alta Floresta, Mato Grosso / Geochemistry and geochronology U-Pb Shrimp of granites from Peixoto de Azevedo: Alta Floresta Gold Province

    Scientific Electronic Library Online (English)

    Fernanda Rodrigues da, Silva; Márcia Aparecida Sant' Ana, Barros; Ronaldo, Pierosan; Francisco Edígio Cavalcante, Pinho; Mara Luiza Barros Pita, Rocha; Bruno Rodrigo, Vasconcelos; Samantha Evelyn Max, Dezula; Carla, Tavares; Jhonattan, Rocha.

    2014-09-01

    Full Text Available A análise de dados petrográficos, geoquímicos e geocronológicos de granitos do Domínio Peixoto de Azevedo, Mato Grosso, na porção leste da Província Aurífera Alta Floresta, conduziu ao reconhecimento de dois corpos graníticos limitados por grandes falhamentos e zonas de cisalhamento regionais. Na po [...] rção noroeste ocorre biotita granodiorito de granulação grossa, textura inequigranular a porfirítica, metaluminoso à peraluminoso, calcialcalino de alto potássio e magnesiano. Na porção sudeste da área ocorre um biotita monzogranito de granulação grossa, textura equigranular a porfiritica, levemente peraluminoso, calcialcalino de alto potássio e caráter dominantemente ferroso. Datações U-Pb (SHRIMP) mostraram que o biotita monzogranito apresenta uma idade de 1869 ± 10 Ma, similar à Suíte Intrusiva Matupá, enquanto que o biotita granodiorito apresenta idade de 1781 ± 10 Ma, que é a idade esperada para o Granito Peixoto. As duas unidades mostram padrões de elementos terras raras com enriquecimento de leves sobre pesados e anomalia negativa de Eu (LaN/YbN " 7,6 a 17,31 e Eu/Eu* entre 0,46 - 0,72 para o biotita monzogranito e LaN/YbN " 7,13 a 29,09 com razões Eu/Eu* entre 0,25 - 0,40 para o biotita granodiorito). O padrão dos elementos traço para ambos apresenta anomalias negativas de Ba, P, Ti e Nb, indicando uma evolução por fracionamento mineral e associação com fontes modificadas por subducção e envolvimento crustal. Neste trabalho, sugere-se que o monzogranito Matupá foi gerado em ambiente de margem continental ativa, num estágio maduro. Para o biotita-granodiorito Peixoto, duas hipóteses são sugeridas: (a) formação num ambiente de arco magmático mais jovem associado ao Magmatismo Colíder ou (b) gerado em ambiente extensional, relacionado à quebra do efêmero Supercontiente Columbia. Abstract in english The analysis of petrographic, geochemical and geochronological data of granites in the Peixoto de Azevedo region, Mato Grosso, Brazil, in the eastern portion of the Alta Floresta Gold Province, led to the recognition of two granitic bodies bounded by regional major faults and shear zones. In the nor [...] thwestern portion a body with featured as biotite granodiorite, coarse-grained, with porphyritic to inequigranular texture, metaluminous to peraluminous, high-K calc-alkaline and magnesium character. In the southeastern portion of the area, a biotite monzogranite coarse-grained, with equigranular to porphyritic texture, slightly peraluminous, high-K calc-alkaline and dominantly of ferrous character. U- Pb dating (SHRIMP) showed that the biotite monzogranite has an age of 1869 ± 10 Ma, similar to the Matupá Intrusive Suite, while the biotite granodiorite has an age of 1781 ± 10 Ma, that is the age expected to Peixoto Granite. Both units show patterns of rare earth elements with enrichment of light over heavy and negative Eu anomaly (LaN/YbN " 7.6 to 17.31 and ratios Eu/Eu* between 0.46 - 0.72 for biotite monzogranite and LaN/YbN " 7.13 to 29.09 with ratios Eu/Eu* between 0.25 - 0.40 for the biotite granodiorite). Trace elements pattern for both present negative anomalies of Ba, P, Ti and Nb indicating an evolution from mineral fractionation and subduction related sources. In this paper, it is sugested that the monzogranite Matupá was developed in mature arc tectonic environment. For the Peixoto Granite, two hypotheses are suggested: (a) it was developed in younger magmatic arc environment associated with the Colider Magmatism or (b) it was generated in extentional tectonic environment during the Columbia Supercontinent break up.

  14. 2005 dossier: granite. Tome: phenomenological evolution of the geologic disposal

    International Nuclear Information System (INIS)

    This document makes a status of the researches carried out by the French national agency of radioactive wastes (ANDRA) about the phenomenological aspects of the geologic disposal of high-level and long-lived radioactive wastes (HLLL) in granite formations. Content: 1 - introduction: ANDRA's research program on disposal in granitic formation; 2 - the granitic environment: geologic history, French granites; 3 - HLLL wastes and disposal design concepts; 4 - identification, characterization and modeling of a granitic site: approach, geologic modeling, hydrologic and hydro-geochemical modeling, geomechanical and thermal modeling, long-term geologic evolution of a site; 5 - phenomenological evolution of a disposal: main aspects of the evolution of a repository with time, disposal infrastructures, B-type wastes disposal area, C-type wastes disposal area; spent fuels disposal area, radionuclides transfer and retention in the granitic environment; 6 - conclusions: available knowledge, methods and tools for the understanding and modeling of the phenomenological evolution of a granitic disposal site. (J.S.)

  15. Nature and origin of Proterozoic A-type granitic magmatism in the southwestern United States of America

    Science.gov (United States)

    Anderson, J. Lawford; Bender, E. Erik

    1989-06-01

    The mountain ranges of Arizona and adjacent California and Nevada contain large areas underlain by Proterozoic anorogenic granites comprising the southwesternmost portion of a transcontinental belt of 1.4-1.5-Ga-old anorogenic complexes that extends across North America northeast into Labrador. Of these, a two-mica, monazite-bearing granitic suite resides in central and southeastern Arizona as part of a peraluminous subprovince that is bordered on the south (southern Arizona to Sonora) and west (western Arizona and adjacent portions of California and Nevada) by marginally metaluminous granites bearing biotite-sphene ± hornblende and fluorite. All of these 1.4-Ga granites are distinctly more potassic, iron-enriched (relative to Mg), and depleted in Ca, Mg and Sr in contrast to typical orogenic granitoids. In general, the large-ion lithophile-element enriched composition is a consequence of limited melting of a water-deficient crustal source at depths greater than 25-37 km. For the peraluminous granites, this contrast is less extreme, perhaps resulting from a larger degree of melting as a consequence of a greater metasedimentary component and water in its crustal source. The anorogenic granitic magmas intruded into the upper crust at depths of 8-17 km or shallower at temperatures up to 790°C. The most dramatic variation in the crystallization-intensive parameters resides in the oxygen fugacity, which spans three orders of magnitude. Relative to other anorogenic suites, all of the magmas crystallized at elevated levels of ƒ O 2 as reflected in their assignment to the anorogenic magnetite series. Yet a regionally significant rise in primary ƒ O 2 levels, unmatched elsewhere in the transcontinental belt, occurs for plutons in western Arizona, including the Holy Moses and Hualapai granites. The most extreme case is the Hualapai granite whose biotite {Fe}/{( Fe + Mg)} ratios drop (due to high ƒ O 2) to a low of 0.27, down from more typical levels of 0.54 to 0.75. Such extreme variations in primary levels of oxygen fugacity must be an indirect imprint of regional changes of the level of oxidation of the lower crust. The high-f O 2 Holy Moses and Hualapai plutons have intruded near the regional boundary between the metaluminous and peraluminous granites and appear to be imaging a major change in the level of oxidation of the lower crust. This boundary is also approximately equivalent to significant changes in the Nd and Pb isotopic compositions of these granites and the metamorphic and magmatic character of the older orogenic terrane. On a global scale, the crust-forming orogenies ended by 1.6 Ga ago and the continents entered a long-lived era dominated by localized extension and transcontinental intrusion of anorogenic potassic rapakivi granite, mafic dike swarms, charnockite and anorthosite. The absence of orogenic deformation implies that plate consumption became intraoceanic during this time. The profuse and widespread nature of the igneous activity has no Phanerozoic analogue and is considered to be unique to the Proterozoic. A crustal overturn model ties the magmatism to heating within a largely undepleted subcontinental mantle, the eventual rise of mantle plumes, and the transfer of heat into the youthful, undifferentiated Proterozoic crust. Subsequent melting and rise of potassic granitic magmas from the lower crust leads to considerable crustal reorganization, a process that would continue until both the mantle and crust reached a stable configuration.

  16. Granite suites and supersuites of eastern Australia

    International Nuclear Information System (INIS)

    Separate granite plutons in southeastern Australia can commonly be grouped into suites on the basis of shared similarities in field, petrographic and compositional data. Granites in different plutons of the same suite share common properties or exhibit a sequence of such features Rocks of the same suite are co genetic, but the details of their genesis need not be known or agreed on, to group granite units in such a way. These rocks are co genetic in the sense that they shared a similar petrogenesis and were derived from source materials of essentially the same composition, whereas differences between suites reflect analogous differences in their source rocks. The term suite is lithologic or lithodemic in a stratigraphic sense and is closely analogous to the lithostratigraphic term group As such, the plutons within a suite need not be of the same age, and age is not a factor in recognising a suite. However, the fact that the petrogenesis of the components of a suite resulted in such similar products means that their ages are likely to be similar Granite plutons that share many similar features, but which also show distinct differences and which may be assigned to more than one suite, may be grouped into supersuites. The allocation of granites to suites is fundamental to understanding their petrogenesis. Suites vary in the complexity of their compositional variation. Simple suites show variations in element abundances that are highly correlated and the dispersion of comighly correlated and the dispersion of composition within such suites is considered to result from varying degrees of fractionation of entrained restite from a melt. Intricate suites vary in composition in more complex ways and their variation is considered to be a consequence of processes such as fractional crystallisation. Any mineralisation is generally associated with intricate suites, and the occurrence of mineralisation and its precise character is generally specific to particular suites. If isotopic compositional dispersion within a granite suite is observed, a process of magma mixing or mingling is commonly invoked. A particular case where isotopic dispersion would occur is that when a mantle-derived component partly melts and then mingles with a crustal magma (Barbarin 1991); the more felsic rocks would be isotopically more evolved than the mafic ones. Granite derived from heterogeneous source rocks, particularly granites formed from relatively low degrees of partial melting from metasedimentary rocks, might be expected to reflect that lack of isotopic uniformity in their source compositions. For example, Chappell et al. (1999) noted that the initial 87Sr/86Sr values for 10 granites sampled from various parts of the Jillamatong pluton show a range of 0.0039, approximately 50-fold that of analytical uncertainty. For this very mafic unit of the S-type Bullenbalong Suite, there is no systematic variation of strontium isotopic composition with SiO2, although samples of more felsic members of the Bullenbalong Suite and Supersuite show a systematic decrease in initial 87Sr/86Sr with increase in SiO2. This observation indicates that variation in initial isotope ratios is here source related, and not magma-mingling related. Copyright (2001) Geological Society of Australia

  17. Late-Hercynian intrusion-related gold deposits: An integrated model on the Tighza polymetallic district, central Morocco

    Science.gov (United States)

    Éric, Marcoux; Khadija, Nerci; Yannick, Branquet; Claire, Ramboz; Gilles, Ruffet; Jean-Jacques, Peucat; Ross, Stevenson; Michel, Jébrak

    2015-07-01

    Gold have been recently recognized in the Tighza (formerly Jebel Aouam) district, in the Hercynian belt of central Morocco. This district has long been known for its W mineralization, as well as major Pb-Ag-Zn, and minor Sb-Ba deposits, all geographically associated with late-Hercynian calc-alkaline magmatism. Gold mineralization in the district is mainly hosted by thick W-Au quartz veins located around the "Mine granite" small granitic plug. Within the veins, gold grade is highest (up to 70 g/t) close to the granite but rapidly decreases going outward from the granite, defining a perigranitic zoning. Anomalous gold grades have also been measured in hydrothermal skarn layers close to two other granitic plugs (Kaolin granite and Mispickel granite), associated with disseminated As-Fe sulfides. The paragenetic sequence for the W-Au quartz veins shows three stages: (1) an early oxidized stage with wolframite-scheelite associated with early quartz (Q1), (2) an intermediate Bi-As-Te-Mo-Au sulfide stage with loellingite, bismuth minerals and native gold with a later quartz (Q2), restricted to a narrow distance from the granite, and (3) a late lower temperature As-Cu-Zn-(Pb) stage with abundant massive pyrrhotite, arsenopyrite and sphalerite, locally forming independent veins ("pyrrhotite vein"). Both Q1 hyaline and Q2 saccharoidal gold-bearing quartz display aqua-carbonic fluids with minor H2S and Cu and an homogeneous composition (81 mole% H2O, 18 mole% CO2 and about 1 mole% NaCl). The trapping pressure is estimated to 1.5-2 kbar with temperature ranging from 300 to 350 °C. Q1 inclusions have exploded indicating an uplift of the Tighza block, that lead to saccharoidal Q2 quartz deposition with multiphase NaCl-saturated fluid inclusions. 40Ar/39Ar dating demonstrates that the "Mine granite", tungsten skarnoid, scheelite-molybdenite veins, and very likely gold-bearing veins are coeval, emplaced at 286 ± 1 Ma. Multiple and widespread metal sources are indicated by radiogenic isotope studies. Nd and Sr isotope compositions of scheelite and granites suggest the participation of a juvenile component while lead isotopes demonstrate a major participation of the basement. Both gold mineralization and zoning suggest that the system developed at the end of the magmatic activity, accompanying a major transition in magmatic fluid composition. The morphology of the gold-bearing mineralization is dependent of the permeability and the reactivity of host-rocks: focus circulation of fluids through pre-existing tectonic corridors, reactivated by late-Hercynian intrusions favor the formation of large W-type gold veins, while infiltration of fluid within reactive stratigraphic layers gives rise to skarn mineralization. A 40Ar/39Ar date (W1 north vein: 291.8 ± 0.3 Ma) indicates that hydrothermal circulation predates gold and tungsten deposition in open fractures as well as Mine granite emplacement. The W-Au mineralization preceded the onset of a large convective hydrothermal cell around the intrusion that led to the formation of the Pb-Ag-Zn mined veins. The Tighza polymetallic district displays numerous similarities with the R-IRG model that was defined in the American Cordillera, such as thermal and zonation patterns, carbonic hydrothermal fluids and chronology of intrusion and related deposits, but also provides new insight to the R-IRG model such as wide Au-quartz veins instead of sheeted Au-veins, oxidation state of the magma, and Sr-Nd isotopic data. These results establish a major magmatic contribution and discard a direct genetic relationship between gold mineralization and major neighboring Pb-Ag-Zn veins. A large number of classic Pb-Zn district of the Western Hercynides belong to the same clan.

  18. The Younger Dryas impact hypothesis: A requiem

    Science.gov (United States)

    Pinter, Nicholas; Scott, Andrew C.; Daulton, Tyrone L.; Podoll, Andrew; Koeberl, Christian; Anderson, R. Scott; Ishman, Scott E.

    2011-06-01

    The Younger Dryas (YD) impact hypothesis is a recent theory that suggests that a cometary or meteoritic body or bodies hit and/or exploded over North America 12,900 years ago, causing the YD climate episode, extinction of Pleistocene megafauna, demise of the Clovis archeological culture, and a range of other effects. Since gaining widespread attention in 2007, substantial research has focused on testing the 12 main signatures presented as evidence of a catastrophic extraterrestrial event 12,900 years ago. Here we present a review of the impact hypothesis, including its evolution and current variants, and of efforts to test and corroborate the hypothesis. The physical evidence interpreted as signatures of an impact event can be separated into two groups. The first group consists of evidence that has been largely rejected by the scientific community and is no longer in widespread discussion, including: particle tracks in archeological chert; magnetic nodules in Pleistocene bones; impact origin of the Carolina Bays; and elevated concentrations of radioactivity, iridium, and fullerenes enriched in 3He. The second group consists of evidence that has been active in recent research and discussions: carbon spheres and elongates, magnetic grains and magnetic spherules, byproducts of catastrophic wildfire, and nanodiamonds. Over time, however, these signatures have also seen contrary evidence rather than support. Recent studies have shown that carbon spheres and elongates do not represent extraterrestrial carbon nor impact-induced megafires, but are indistinguishable from fungal sclerotia and arthropod fecal material that are a small but common component of many terrestrial deposits. Magnetic grains and spherules are heterogeneously distributed in sediments, but reported measurements of unique peaks in concentrations at the YD onset have yet to be reproduced. The magnetic grains are certainly just iron-rich detrital grains, whereas reported YD magnetic spherules are consistent with the diffuse, non-catastrophic input of micrometeorite ablation fallout, probably augmented by anthropogenic and other terrestrial spherular grains. Results here also show considerable subjectivity in the reported sampling methods that may explain the purported YD spherule concentration peaks. Fire is a pervasive earth-surface process, and reanalyses of the original YD sites and of coeval records show episodic fire on the landscape through the latest Pleistocene, with no unique fire event at the onset of the YD. Lastly, with YD impact proponents increasingly retreating to nanodiamonds (cubic, hexagonal [lonsdaleite], and the proposed n-diamond) as evidence of impact, those data have been called into question. The presence of lonsdaleite was reported as proof of impact-related shock processes, but the evidence presented was inconsistent with lonsdaleite and consistent instead with polycrystalline aggregates of graphene and graphane mixtures that are ubiquitous in carbon forms isolated from sediments ranging from modern to pre-YD age. Important questions remain regarding the origins and distribution of other diamond forms (e.g., cubic nanodiamonds). In summary, none of the original YD impact signatures have been subsequently corroborated by independent tests. Of the 12 original lines of evidence, seven have so far proven to be non-reproducible. The remaining signatures instead seem to represent either (1) non-catastrophic mechanisms, and/or (2) terrestrial rather than extraterrestrial or impact-related sources. In all of these cases, sparse but ubiquitous materials seem to have been misreported and misinterpreted as singular peaks at the onset of the YD. Throughout the arc of this hypothesis, recognized and expected impact markers were not found, leading to proposed YD impactors and impact processes that were novel, self-contradictory, rapidly changing, and sometimes defying the laws of physics. The YD impact hypothesis provides a cautionary tale for researchers, the scientific community, the press, and the broader public.

  19. Shrimp U-Pb age and Sr-Nd isotopes of the Morro do Baú mafic intrusion: implications for the evolution of the Arenópolis volcano-sedimentary sequence, Goiás Magmatic Arc

    Scientific Electronic Library Online (English)

    Márcio M., Pimentel; Maria Helena B. M., Hollanda; Richard, Armstrong.

    2003-09-01

    Full Text Available A seqüência vulcano-sedimentar de Arenópolis, localizada na porção sul do Arco Magmárico de Goiás, inclui uma associação de rochas vulcânicas calci-alcalinas de arco com ca. 900 Ma de idade, constituída de rochas variando em composição entre basaltos e riolitos, metamorfisados em fácies xisto verde [...] a anfibolito. Pequenos corpos sub-vulcânicos de gabros a granitos calci-alcalinos são também reconhecidos. A intrusão do Morro do Baú é a maior dessas intrusões, compreendendo dioritos e gabros. Cristais de zircão separados de uma amostra de gabro e analisados no SHRIMP I indicaram a idade 206Pb/238U média de 890 +/- 8 Ma, mostrando que a intrusão é grosseiramente contemporânea, ou talvez um pouco mais jovem que as rochas vulcânicas. Ao contrário das rochas metavulcânicas, que são juvenis, a composição isotópica de Nd do gabro do Morro do Baú indica forte contaminação com material siálico arqueano (T DM de 2.8 Ga e EpsilonNd(T) igual a -9.7), representado na área por uma pequena fatia tectônica de rocha gnáissica arqueana/paleoproterozóica (gnaisse Ribeirão), e que representa a rocha encaixante da intrusão gabro-diorítica. A idade de cristalização de ca. 890 Ma representa, portanto, um limite mínimo para a acresção tectônica do gnaisse Ribeirão às rochas mais jovens da seqüência de Arenópolis. Os dados sugerem que esse evento foi precoce na evolução da seqüência vulcano-sedimentar de Arenópolis, provavelmente entre ca. 920 e 890 Ma. Abstract in english The Arenópolis volcano-sedimentary sequence is located in the southern part of the Goiás Magmatic Arc and includes a ca. 900 Ma calc-alkaline arc sequence made of volcanic rocks ranging in composition from basalts to rhyolites, metamorphosed under greenschist to amphibolite facies. Small calc-alkali [...] ne gabbro to granite sub-volcanic bodies are also recognized. The Morro do Baú intrusion is the largest of these intrusions, and is made of gabbros and diorites. Zircon grains separated from one gabbro sample and analyzed by SHRIMP I yielded the mean 206Pb/238U age of 890 +/- 8 Ma, indicating that the intrusion is roughly coeval or only slightly younger than the Arenópolis volcanics. Contrary to the metavolcanics, which are juvenile, the Nd isotopic composition of the Morro do Baú gabbro indicates strong contamination with archean sialic material (T DM of 2.8 Ga and EpsilonNd(T) of -9.7), represented in the area by an allochthonous sliver of archean/paleoproterozoic gneisses (Ribeirão gneiss) which are the country-rocks for the gabbro/dioritic intrusion. The emplacement age of ca. 890 Ma represents a minimum age limit for the tectonic accretion of the gneiss sliver to the younger rocks of the Arenópolis sequence. The data suggest that this happened early in the evolution of the Goiás Magmatic Arc, between ca. 920 and 890 Ma.

  20. The Pedregal granite (Portugal: petrographic and geochemical characterization of a peculiar granitoid

    Directory of Open Access Journals (Sweden)

    Ferreira, J. A.

    2014-12-01

    Full Text Available The Pedregal granite outcrops in the Central Iberian Zone, northern Portugal, in the eastern border of a synorogenic variscan granite-migmatite complex sub-concordant with the regional metamorphic structures. It is a granitoid (ca. 3 km2 with an elongated NW-SE shape intruded in staurolite-micaschist and banded gneiss-migmatite rocks, with local igneous breccias in the contact. The country rocks belong to a metapelitic and metasammitic sequence of Edicarian-Cambrian age, known as the “Complexo Xisto-Grauváquico” (CXG which shows a main regional foliation with a NW-SE to NNW-SSE direction. The Pedregal granite is peraluminous (its A/CNK parameter ranges from 1.18 to 1.62, with a magnesian and alkali to alkali-calcic signature. The peculiar features of the granite are high contents of Zr (389 to 435 ppm and a LREE flat pattern, which are uncommon characteristics for granitic rocks, as well as the corroded shape of the biotite, and the large amount of secondary muscovite. These peculiar features distinguish it from the adjacent synorogenic granites. The field, petrographical and chemical features of the Pedregal granite are in accordance with a second phase of partial melting of a residuum, depleted by melt segregation during a first melting episode with the involvement of peritectic garnet and abundant residual biotite with LREE- and Zr-bearing accessory minerals. Besides, the intrusive character of the granite, and the presence of metasedimentary xenoliths point out to a secondary diatexite.El granito de Pedregal aflora en la Zona Centro-Ibérica, en el norte de Portugal, en el borde oriental de un complejo granito-migmatítico sinorogénico varisco, subconcordante con las estructuras metamórficas regionales. Es un granitoide (ca. 3 km2 de forma elongada NW-SE, que intruye en micaesquistos estaurolíticos y en rocas gneissico- migmatíticas bandeadas, con brechas ígneas locales en el contacto. Las rocas encajantes pertenecen a una secuencia metapelítica-metasamítica de edad Ediacariense - Cámbrico, conocida como el “Complejo Esquisto-Grauváquico” (CEG, que muestra una foliación regional principal NW-SE a NNW- SSE. El granito de Pedregal es peralumínico (el parámetro A/CNK oscila desde 1.18 hasta 1.62, con una composición magnesiana, entre alcalina y alcalino-cálcica. Sus características peculiares son el alto contenido de Zr (389–435 ppm y de tierras raras ligeras (LREE que presentan un patrón plano, la forma corroída de la biotita, y la gran cantidad de moscovita secundaria. Estas características peculiares lo distinguen de los otros granitos sinorogénicos adyacentes. Las características de campo, petrográficas y químicas del granito de Pedregal parecen apuntar a una segunda fase de fusión parcial de un residuo, empobrecido por la segregación de fundido durante una primera fase de fusión con participación de granate peritéctico y abundante biotita residual con minerales accesorios portadores de LREE y Zr. Además, el carácter intrusivo del granito, y la presencia de xenolitos metasedimentarios sugieren una diatexita secundaria.

  1. Geometry of Caldera Superfaults and Emplacement of Their Associated Intrusions

    Science.gov (United States)

    Hildyard, R.; Kokelaar, P.

    2006-12-01

    Caldera collapse generally involves large-scale fault movements, in some cases involving an annular structure (ring-fault) but commonly involving several intersecting fault strands. Fault displacements are typically hundreds of meters in hours or days. The geometry of caldera faults has often been depicted as inward dipping and bounding a coherent crustal block, but such `key-stone'-like geometry does not facilitate subsidence unless associated with overall extension. Recent modelling, experimentation and comparison with natural analogs show that bounding faults typically dip outwards. Reappraisal of the deeply dissected Glencoe Volcano in Scotland has shown that the archetypal bounding `ring-fault' and associated intrusions, which define an ellipse 14x8 km, comprise near vertical, outward-dipping structures that have accommodated ~700 m of subsidence. Along certain sections, pseudotachylyte occurs at the margins of voluminous (1-2000 m wide) fault intrusions of rhyolite, monzonite, diorite, tonalite and granite. The pseudotachylyte and rhyolite show various mingling relationships indicating a fluid and particulate-state interaction during emplacement. The inner contacts, against the subsided country rocks, are planar while the outer contacts are highly irregular, both on a large scale (100's m) and a small scale (10 cm -1 m). In one section, a fault strand cuts a hydrothermal system recorded by veins of quartz, epidote, pyrite and sericite. We infer that both friction melts and magmas were transformed explosively to froth or spray where they encountered rapid decompression along dilatant sections of the active superfaults. The friction melts were driven upwards, plastering separate fault surfaces, and were rapidly followed by fragmented rhyolite magma and then fluid magma that formed fault intrusions. The irregular outer contacts of the fault intrusions are interpreted as recording instantaneous explosive disruption of pressurized hydrothermal systems that were intersected by the dilational faults. Lithic breccias were removed from the rapidly formed cavities prior to the first arrival of decompressed melt-spray. The involvement of outward-dipping faults at caldera volcanoes suggests that fault-plane dilation commonly promotes explosivity along these structures.

  2. Adsorption of radionuclides onto granite materials

    International Nuclear Information System (INIS)

    This paper deals with laboratory determination of adsorption isotherms parameters. Granite from the central moldanubian pluton, site Panske Dubenky. Czech Republic, was chosen for the experiment. The place is one of the candidate sites to build a deep nuclear waste disposal facility. A batch experiment was performed in two modes, differing in the way of addition of radioactive nuclide 90Sr. From this experiment- distribution coefficients for a linear isotherm or parameters for Langmuir isotherm were obtained. In addition, a through-diffusion experiment was performed. The objective of this experiment was to find whether some of the radionuclides 137Cs, 90Sr, 125I is able to penetrate through the pores of a granite slice barrier between two solutions of different concentrations. During the period of the experiment no radionuclide was detected reliably. (author)

  3. Physics of the granite sphere fountain

    Science.gov (United States)

    Snoeijer, Jacco H.; der Weele, Ko van

    2014-11-01

    A striking example of levitation is encountered in the "kugel fountain" where a granite sphere, sometimes weighing over a ton, is kept aloft by a thin film of flowing water. In this paper, we explain the working principle behind this levitation. We show that the fountain can be viewed as a giant ball bearing and thus forms a prime example of lubrication theory. It is demonstrated how the viscosity and flow rate of the fluid determine (i) the remarkably small thickness of the film supporting the sphere and (ii) the surprisingly long time it takes for rotations to damp out. The theoretical results compare well with measurements on a fountain holding a granite sphere of one meter in diameter. We close by discussing several related cases of levitation by lubrication.

  4. Possible genetic link between I-type granite and orogenic gold deposits in Egypt (metamorphic-magmatic interaction?)

    Science.gov (United States)

    Abd El Monsef, Mohamed

    2015-04-01

    The orogenic gold deposits are a distinctive type of deposits that revealed unique temporal and spatial association with an orogeny. Where, the system of gold veins and related ore minerals was confined to hydrothermal solutions formed during compressional to transpressional deformation processes at convergent plate margins in accretionary and collisional orogens, with the respect to ongoing deep-crustal, subduction-related thermal processes. In Egypt, most of vein-type and dyke-type gold mineralization are restricted to granitic rocks or at least near of granitic intrusion that seems to have had an important influence on gold mineralization. Shear zone-related, mesothermal gold deposits of Fatira and Gidami mines in the northern Eastern Desert of Egypt are found within granitic bodies or at the contact between granites and metavolcanic rocks. The hosting-granitic rocks in Fatira and Gidami areas are mainly of granodioritic composition (I-Type granite) which is related to calc-alkaline magmatic series. However, Fatira granitoids were developed within island arc tectonic settings related to mature island arc system (Late-orogenic stage), at relatively low temperature (around 660° C) and medium pressure between (5 - 10 Kbar). On the other hand, Gidami granitoids were developed during the collision stage in continental arc regime related to active continental margin (Syn-orogeny), which were crystallized at relatively high temperature (700-720° C) and low pressure (around 0.1 Kbar). The ore mineralogy includes pyrite, chalcopyrite, sphalerite, covellite, ilmenite, goethite ± pyrrhotite ± pentlandite ± galena ± molybdenite. Native gold is detected only in Gidami mineralization as small inclusions within pyrite and goethite or as tiny grains scattered within quartz vein (in close proximity to the sulfides). In Fatira deposits, it is detected only by microprobe analysis within the crystal lattice of pyrite and jarosite. Fluid inclusions study for the mineralized ores revealed two main groups of fluid inclusions in both areas: A) Aqueous inclusions (H2O-NaCl±KCl system), and B) Carbonic inclusions (H2O-CO2-NaCl±CH4). A drop of pressure during the migration of these fluids to shallower depths along the shear zones was the main reason for phase separation. Isochores calculation from microthermometric results proved that, the P-T boundary conditions outlined for Fatira gold deposits are of 275° to 297° C and between (0.2 - 1.2 Kbar); and of 277° to 300° C and between (0.2 - 1 Kbar) for Gidami gold deposits. The normalization Chondrite patterns of rare earth elements (REEs) for the gold-ore deposits with the surrounding I-type granitic rocks exhibit an obvious similarity and positive correlation. The geological, mineralogical, geochemical and fluid inclusions studies revealed a genetic link between gold mineralization and intrusion of calc-alkaine granitic magma. Whereas, The granitic magma acts as a supplier for the ore-bearing fluid and as a heat source for metamorphic processes, leading to hydrothermal convection currents.

  5. Performance assessment of geological isolation systems for radioactive waste. Disposal in granite formations

    International Nuclear Information System (INIS)

    In the framework of the PAGIS project of the CEC Research Programme on radioactive wastes, a performance assessment of a repository of vitrified HLW in granite was carried out. Three disposal sites were considered: the reference site Auriat and two alternative sites, Barfleur and a site in the U.K. The report describes the methodology adopted (a deterministic and a stochastic approach) with the corresponding data base and the models used. A parametric study of sub-systems (near field, far field and biosphere) was carried out by CEA-ANDRA using AQUARIUS, DIMITRIO and BIOS. A global evaluation of the performances was carried out by CEA-IPSN using MELODIE code. The results of deterministic calculations showed for Auriat a maximum dose equivalent evaluated at 6.10-3m Sv/a arising 3 millions years after disposal. Results of human intrusion scenario analyses, uncertainty analyses and global sensitivity analyses are presented. This document is one of a set of 5 reports covering a relevant project of the European Community on a nuclear safety subject having very wide interest. The five volumes are: the summary (EUR 11775-EN), the clay (EUR 11776-EN), the granite (EUR 11777-FR), the salt (EUR 11778-EN) and the sub-seabed (EUR 11779-EN)

  6. Degradation studies on granite in alkaline solution

    International Nuclear Information System (INIS)

    Batch leaching experiments of granite with the artificial cement leachate and the leachate of low-alkalinity-cement (LW) were carried out to evaluate the effect of the hiperalkaline plume on the environment of the high-level and TRU radioactive waste repository. Dissolution of Si and Al from feldspar included in the granite and precipitation of C-S-H were confirmed from the results of the leaching experiments with artifitial cement leachate. From this result it was found that the composition of surrounding rock changed. It also suggested that the retardation factor of migration of radionuclides would change. On the contrary, only decrease of concentrations in Si, Al and Ca in the leachate was observed in the experiment with LW. This result might indicate that C-S-H and/or C-A-S-H precipitated as secondary minerals in the LW case. From these results, it was considered that the hyperalkaline plume from the cementitious leachate might caused the change of disposal conditions such as the change in distribution coefficients of rock by precipitation of the secondary mineral and the increase in hydraulic conductivity by the dissolution of rock. On the other hand, the influences of the LW would be comparatively small, because LW and granite might equilibrate in short time. (author)

  7. Diffusion of uranium in the granite rock

    International Nuclear Information System (INIS)

    In the safety assessment of high level radioactive waste disposal, a significant retardation factor of radionuclides leaking from an underground repository can be expected. When radionuclides released from an underground repository are transported with the moving groundwater along cracks in the rock, the radionuclides will be retarded by not only adsorption on the surface of the cracks but also by process diffusion into submicron pores of rock matrix. In this experiments have been performed by process diffusion of uranium in water saturated granite. The measured penetration profile of uranium was composed of two parts. This profile was successfully explained by considering two diffusion paths in granite rock. One diffusion path was possibly a fissure with a width of few microns and another was a submicron pores of granite rock. The orders of magnitude of diffusivities for uranium were 10-12 m2/sec through the fissure and 1015 m2/sec through the submicron pores. The difference between the diffusivities of two path is thought to be caused by small geometrical factor of submicron pores, if to compared with fissures. (author)

  8. Mobile Agents in Intrusion Detection System: Review and Analysis

    OpenAIRE

    Kamaruzaman Maskat; Mohd Afizi Mohd Shukran; Mohammad Adib Khairuddin; Mohd Rizal Mohd Isa

    2011-01-01

    Intrusion Detection System (IDS) is used to detect intrusion and then alert the system administrator about the intrusion. This is what traditional IDS is all about. It is then up to the system administrator to deal with the intrusion. Human intervention is still needed when it comes to dealing with intrusion. This is because traditional IDS could only detect the intrusion but could not, on its own respond towards the intrusion. IDS is only able to alert the system administrator when it detect...

  9. A fluid inclusion and stable isotope study of 200 Ma of fluid evolution in the Galway Granite, Connemara, Ireland

    Science.gov (United States)

    O'Reilly, C.; Jenkin, G. R. T.; Feely, M.; Alderton, D. H. M.; Fallick, A. E.

    Fluid inclusions in granite quartz and three generations of veins indicate that three fluids have affected the Caledonian Galway Granite. These fluids were examined by petrography, microthermometry, chlorite thermometry, fluid chemistry and stable isotope studies. The earliest fluid was a H2O-CO2-NaCl fluid of moderate salinity (4-10 wt% NaCl eq.) that deposited late-magmatic molybdenite mineralised quartz veins (V1) and formed the earliest secondary inclusions in granite quartz. This fluid is more abundant in the west of the batholith, corresponding to a decrease in emplacement depth. Within veins, and to the east, this fluid was trapped homogeneously, but in granite quartz in the west it unmixed at 305-390°C and 0.7-1.8 kbar. Homogeneous quartz ?18O across the batholith (9.5+/- 0.4‰n=12) suggests V1 precipitation at high temperatures (perhaps 600°C) and pressures (1-3 kbar) from magmatic fluids. Microthermometric data for V1 indicate lower temperatures, suggesting inclusion volumes re-equilibrated during cooling. The second fluid was a H2O-NaCl-KCl, low-moderate salinity (0-10 wt% NaCl eq.), moderate temperature (270-340°C), high ?D (-18+/-2‰), low ?18O (0.5-2.0‰) fluid of meteoric origin. This fluid penetrated the batholith via quartz veins (V2) which infill faults active during post-consolidation uplift of the batholith. It forms the most common inclusion type in granite quartz throughout the batholith and is responsible for widespread retrograde alteration involving chloritization of biotite and hornblende, sericitization and saussuritization of plagioclase, and reddening of K-feldspar. The salinity was generated by fluid-rock interactions within the granite. Within granite quartz this fluid was trapped at 0.5-2.3 kbar, having become overpressured. This fluid probably infiltrated the Granite in a meteoric-convection system during cooling after intrusion, but a later age cannot be ruled out. The final fluid to enter the Granite and its host rocks was a H2O-NaCl-CaCl2-KCl fluid with variable salinity (8-28 wt% NaCl eq.), temperature (125-205°C), ?D (-17 to -45‰), ?18O (-3 to+1.2‰), ?13CCO2 (-19 to 0‰) and ?34Ssulphate (13-23‰) that deposited veins containing quartz, fluorite, calcite, barite, galena, chalcopyrite sphalerite and pyrite (V3). Correlations of salinity, temperature, ?D and ?18O are interpreted as the result of mixing of two fluid end-members, one a high-?D (-17 to -8‰), moderate-?18O (1.2-2.5‰), high-?13CCO2 (> -4‰), low-?34Ssulphate (13‰), high-temperature (205-230°C), moderate-salinity (8-12 wt% NaCl eq.) fluid, the other a low-?D (-61 to -45‰), low-?18O (-5.4 to -3‰), low-?13C (<-10‰), high-?34Ssulphate (20-23‰) low-temperature (80-125°C), high-salinity (21-28 wt% NaCl eq.) fluid. Geochronological evidence suggests V3 veins are late Triassic; the high-?D end-member is interpreted as a contemporaneous surface fluid, probably mixed meteoric water and evaporated seawater and/or dissolved evaporites, whereas the low-?D end-member is interpreted as a basinal brine derived from the adjacent Carboniferous sequence. This study demonstrates that the Galway Granite was a locus for repeated fluid events for a variety of reasons; from expulsion of magmatic fluids during the final stages of crystallisation, through a meteoric convection system, probably driven by waning magmatic heat, to much later mineralisation, concentrated in its vicinity due to thermal, tectonic and compositional properties of granite batholiths which encourage mineralisation long after magmatic heat has abated.

  10. U-Th-Pb systematics in hydrothermally altered granites from the Granite Mountains, Wyoming

    International Nuclear Information System (INIS)

    U-Th-Pb systematics were investigated in 15 samples representing two types of deuterically altered Archean granite from Wyoming. The loss of K-feldspar during both types of deuteric alteration was accompanied by an extreme reduction of Pb content from roughly 40 ppm to less than 12 ppm in the most altered samples. Nine of the 15 samples yield anomalously young whole-rock Pb-Pb and Th-Pb ages compared to concordia ages for zircons and to whole-rock Pb-Pb and Th-Pb ages for samples of unaltered granite. The young ages are interpreted to be the result of radiogenic Pb loss during a middle Proterozoic metamorphism that disturbed several isotopic systems in the unaltered granite. The results are discussed. (author)

  11. Intrusive cognitions, anxiety and cancer

    OpenAIRE

    Whitaker, K. L.

    2008-01-01

    Since the recognition (DSM-IV; American Psychiatric Association, 1994) of life-threatening illnesses as a stressor that can precipitate posttraumatic stress disorder (PTSD), research has focussed on the issue of PTSD following cancer. Although the utility of a trauma framework has been questioned, understanding symptoms associated with PTSD such as intrusive cognitions may be critical in understanding psychological distress in cancer patients. Research has found that cancer patients experi...

  12. Intrusion Detection in SCADA Networks

    OpenAIRE

    Barbosa, Rafael Ramos Regis; Pras, Aiko

    2010-01-01

    Supervisory Control and Data Acquisition (SCADA) systems are a critical part of large industrial facilities, such as water distribution infrastructures. With the goal of reducing costs and increasing efficiency, these systems are becoming increasingly interconnected. However, this has also exposed them to a wide range of network security problems. Our research focus on the development of a novel flow-based intrusion detection system. Based on the assumption that SCADA networks are well-behave...

  13. Natural radioactivity of granites used as building materials

    International Nuclear Information System (INIS)

    Sixteen kinds of different granites, used as building materials, imported to Greece mainly from Spain and Brazil, were sampled and their natural radioactivity was measured by gamma-ray spectrometry. The activity concentrations of 238U, 226Ra, 232Th and 4K of granites are presented and compared to those of other building materials as well as other granite types used all over the world. In order to assess the radiological impact from the granites investigated, the absorbed and the effective doses were determined. Although the annual effective dose is higher than the limit of 1 mSv y-1 for some studied granites, they could be used safely as building materials, considering that their contribution in most of the house constructions is very low. An attempt to correlate the relatively high level of natural radioactivity, shown by some of the granites, with their constituent radioactive minerals and their chemical composition, was also made

  14. Interaction between magmatic and tectonic stresses during dyke intrusion Interacción entre esfuerzos magmáticos y tectónicos durante la intrusión de diques

    OpenAIRE

    Jorge Skarmeta

    2011-01-01

    Cataclastic and mylonitic rocks exposed in the southwestern part of the Peninsula de Mejillones, northern Chile, are intruded at high angles of the foliation by younger, steeply inclined (±70°) basaltic dykes that resemble intrusive tension gashes with knife-edge contacts with the country rocks. These late dykes developed sigmoidaly-shaped, preferred orientation paths defined by oriented pyroxene phenocrysts that vary in size, aspect ratio, concentration and distribution across the width of...

  15. Preparation of glass-ceramic materials from granitic rocks waste

    OpenAIRE

    Gamal A. Khater

    2012-01-01

    Crystallisation of glasses based on the diopside-anorthite eutectic system, containing increased amount (10–50 wt.%) of wollastonite based on granite quarries waste, was investigated for the preparation of cheap technical glass-ceramic materials. Granite quarries waste consisted of about 52 wt.% of the batch constituents depending on composition. The granite quarries waste composition was sometimes modified by adding other ingredients such as dolomite, limestone and Al2O3. Batches were melt...

  16. Pregnant and parenting adolescents and their younger sisters: the influence of relationship qualities for younger sister outcomes.

    Science.gov (United States)

    East, P L; Shi, C R

    1997-04-01

    On the basis of social modeling theory and a sibling interaction hypothesis, it was hypothesized that specific relationship qualities between a pregnant or parenting teen and her younger sister would be associated with permissive younger sister outcomes, such as permissive childbearing attitudes and permissive sexual behavior. Results indicated that negative relationship qualities, such as rivalry, competition, and conflict, were more closely related to younger sisters engaging in problem delinquent-like behavior and sexual behavior than were positive relationship qualities, such as warmth and closeness. Additionally, a shared friendship network with the older sister was found to be associated with extensive younger sister problem behavior and sexual behavior. Three potential explanatory processes are discussed. PMID:9113588

  17. The behaviour of rare metals in Piaoac granite massif, Vietnam

    Science.gov (United States)

    Xuan Ben, Trinh; Van Hoai, Nguyen; Visnepskaya, Yu. E.

    The Piaoac granite massif is Paleogene in age and genetically related to surrounding rare metal mineralization. The massif consists of two-mica granite and aplite granite. The Piaoac granite is different from normal granite in its geochemical characteristics. Content of uranium is about 3-4 times more and the ratio U/Th is lower. Besides the radioactive elements, many rare metals have been found with high content in comparison with normal granite. W, Ag, Li, Sn and Nb are 200, 60, 20, 10 and 10 times higher, respectively. Hydrothermal metasomatism is widespread in the Piaoac granite massif, especially in its periphery (in endocontact). In addition, there is widespread quartz-muscovite greisenization of high temperature (T = 550° C) . In this process W- and Sn-bearing quartz veins had been formed with a new typical assemblage of accessory minerals, such as: topaz, rutile, cassiterite, wolframite, etc. In a detailed section, across the greisenized granite we note the gradational characteristics adjacent to quartz-wolframite veins or blocks. Study of the relation between the grade of greisenization and the content of rare metals shows that the radioactive elements are inversely, and W, Sn, Li, Be are linearly, correlated with greisenization. In the northwest contact of the Piaoac massif with limestone, quartz lepidolite greisen of medium temperature ( T = 450° C) is widespread in the granite side. Overlaying it are fluorite-hydromuscovite-bertrandite metasomatites of low temperature.

  18. Portuguese granites associated with Sn-W and Au mineralizations

    Directory of Open Access Journals (Sweden)

    Ana M.R. Neiva

    2002-01-01

    Full Text Available In northern and central Portugal, there are different tin-bearing granites. Most of them are of S-type, others have mixed characteristics of I-type and S-type granites and a few are of I-type. Tin-tungsten deposits are commonly associated with Hercynian tin-bearing S-type granites. Some quartz veins with wolframite are associated with an I-type granite, which has a low Sn content. In suites of tin-bearing S-type granitic rocks, Sn content increases as a function of the degree of fractional crystallization. Greisenizations of two-mica S-type granites associated with tin-tungsten mineralizations are accompanied by an increase in SiO2, H2O+, Sn, W, Nb, Ta, Rb, Zn, and Pb and decrease in MgO, Na2O, V, Sc,Zr, and Sr. The granite associated with the Jales gold deposit is of S-type and strongly differentiated like the tin-bearing S-type granites, but it has a very low Sn content. During fractional crystallization, Si, Rb, Sn, Pb, Au, As, Sb, and S increase. During increasing degree of hydrothermal alteration of this granite at the gold-quartz vein walls, there are progressive increases in K2O, H2O+, Sn, Cs, Cu, Pb, Au, Sb, As, and S.

  19. Diffusion experiment of a radionuclide in granitic rock cores

    International Nuclear Information System (INIS)

    An effective diffusion coefficient of neptunium-237 which is one of hazardous long-lived radionuclide including high level radioactive waste was determined by using 40 mm diameter and 5 mm thick disks under an aerobic condition. An alpha autoradiography was performed for cross sections of a 20 mm thick granite disk to study the penetrated neptunium into granite. The effective diffusion coefficient of neptunium diffused through a water saturated granite was about 2.5 x 10-13 m2/sec. The autoradiograph of solid state track detectors clearly showed that biotite constituting granite has storage pores and keep diffusing species in it. (author)

  20. Classification and Importance of Intrusion Detection System

    Directory of Open Access Journals (Sweden)

    Rajasekaran K

    2012-08-01

    Full Text Available An intrusion detection system (IDS is a device or software application that monitors network or system activities for malicious activities or policy violations and produces reports to a Management Station. Some systems may attempt to stop an intrusion attempt but this is neither required nor expected of a monitoring system. Due to a growing number of intrusion events and also because the Internet and local networks have become so ubiquitous, organizations are increasingly implementing various systems that monitor IT security breaches. This includes an overview of the classification of intrusion detection systems and introduces the reader to some fundamental concepts of IDS methodology: audit trail analysis and on-the-fly processing as well as anomaly detection and signature detection approaches. This research paper discusses the primary intrusion detection techniques and the classification of intrusion Detection system.

  1. Strengthening intrusion detection techniques through emerging patterns

    OpenAIRE

    Grandinetti, Walter M.

    2004-01-01

    In todays world where nearly every company is dependent on the Internet to survive, it is not surprising that the role of intrusion detection has become extremely important within the last decade. Intrusion detection involves determining whether some entity has attempted to gain, or worse, it has gained unauthorized access to the system. The task of current intrusion detection systems is detect possible threats not only from insiders but also from outsiders. Based on our current knowledge,...

  2. Self-adaptive web intrusion detection system

    OpenAIRE

    Guyet, Thomas; Quiniou, Rene?; Wang, Wei; Cordier, Marie-odile

    2009-01-01

    The evolution of the web server contents and the emergence of new kinds of intrusions make necessary the adaptation of the intrusion detection systems (IDS). Nowadays, the adaptation of the IDS requires manual -- tedious and unreactive -- actions from system administrators. In this paper, we present a self-adaptive intrusion detection system which relies on a set of local model-based diagnosers. The redundancy of diagnoses is exploited, online, by a meta-diagnoser to check t...

  3. Classification and Importance of Intrusion Detection System

    OpenAIRE

    Rajasekaran K; Nirmala K

    2012-01-01

    An intrusion detection system (IDS) is a device or software application that monitors network or system activities for malicious activities or policy violations and produces reports to a Management Station. Some systems may attempt to stop an intrusion attempt but this is neither required nor expected of a monitoring system. Due to a growing number of intrusion events and also because the Internet and local networks have become so ubiquitous, organizations are increasingly implementing variou...

  4. Intrusion Detection Using Data Mining Technique

    OpenAIRE

    Stuti Singh; Roshan Srivastava

    2013-01-01

    In reality it is not possible to prevent security breaches completely using the existing security technologies. The intrusion detection plays an important role in network security and information system. However, many current intrusion detection systems (IDSs) are signature based systems. The signature based IDS also known as misuse detection looks for a specific signature to match, and identify an intrusion. When the signatures or patterns are provided, they can detect all known attack patte...

  5. Hybrid Multi-level Intrusion Detection System

    OpenAIRE

    Sahar Selim; Mohamed Hashem; Nazmy, Taymoor M.

    2011-01-01

    Intrusion detection is a critical process in network security. Nowadays new intelligent techniques have been used to improve the intrusion detection process. This paper proposes a hybrid intelligent intrusion detection system to improve the detection rate for known and unknown attacks. We examined different neural network & decision tree techniques. The proposed model consists of multi-level based on hybrid neural network and decision tree. Each level is implemented with the technique which g...

  6. Network Intrusion Detection Types and Computation

    OpenAIRE

    Purvag Patel; Chet Langin; Feng Yu; Shahram Rahimi

    2012-01-01

    Our research created a network Intrusion Detection Math (ID Math) consisting of two components: (1) a way of specifying intrusion detection types in a manner which is more suitable for an analytical environment; and (2) a computational model which describes methodology for preparing intrusion detection data stepwise from network packets to data structures in a way which is appropriate for sophisticated analytical methods such as statistics, data mining, and computational intelligence. We used...

  7. ENSEMBLE DESIGN FOR INTRUSION DETECTION SYSTEMS

    OpenAIRE

    S.Mercy Shalinie; A. Ramamoorthi; T. Subbulakshmi

    2009-01-01

    Intrusion Detection problem is one of the most promising research issues of Information Security. The problem provides excellent opportunities in terms of providing host and network security.Intrusion detection is divided into two categories with respect to the type of detection. Misuse detection and Anomaly detection. Intrusion detection is done using rule based, Statistical, and Soft computing techniques. The rule based measures provides better results but the extensibility of the approach ...

  8. Evolutionary Design of Intrusion Detection Programs

    OpenAIRE

    Ajith Abraham; Crina Grosan; Carlos Martin-Vide

    2007-01-01

    Intrusion detection is the process of monitoring the events occurring in a computer system or network and analyzing them for signs of intrusions, defined as attempts to compromise the confidentiality, integrity, availability, or to bypass the security mechanisms of a computer or network. This paper proposes the development of an Intrusion Detection Program (IDP) which could detect known attack patterns. An IDP does not eliminate the use of any preventive mechanism but it works as the last def...

  9. The SHRIMP zircon U-Pb dating and its geological significance on the volcanic-intrusive rocks in broken crater of Xunwu, Jiangxi province

    International Nuclear Information System (INIS)

    Xunwu broken crater located in the transition zone of Wuyi rise belt and Nanling tectonic belt, controlled by the NE direction Huichang-Xunwu fault belt and the EW direction Sannan-Xunwu fault belt,and developed a volcanic-intrusive rocks that made up of porphyroclastic lava and granite-porphyry. The zircon U-Pb dating with a higher accuracy yields the following results: the age of pyroclastic rocks in the volcanic-intrusive rocks in broken crater is (96.7±1.1) Ma and the age of granite-porphyry is (97.3±0.9) Ma. According to the geological chronology,the boundary between the Early Cretaceous and the Late Cretaceous is (99.6±0.9)Ma, the geological age of the volcanic-intrusive rocks of Xunwu broken crater is early Late Cretaceous. Age determinations of the volcanic-intrusive rocks provide the age evidence for Xunwu broken crater which belong to Yousheng formation. (authors)

  10. The fast evolution of a crustal hot zone at the end of a transpressional regime: The Saint-Tropez peninsula granites and related dykes (Maures Massif, SE France)

    Science.gov (United States)

    Duchesne, Jean-Clair; Liégeois, Jean-Paul; Bolle, Olivier; Vander Auwera, Jacqueline; Bruguier, Olivier; Matukov, Dmitry I.; Sergeev, Sergey A.

    2013-03-01

    Granite and dolerite occurring in the eastern unit of the Maures Massif (southern France Variscan belt) were emplaced in the waning stage of the evolution of a dextral shear zone along the Gondwana border with Laurasia. We present a geochronological and petro-geochemical study (major and trace elements, Sr-Nd isotopes) of (1) the foliated Moulin Blanc cordierite granite and related foliated dykes; (2) the equant Camarat granite and dyke; and (3) the andesite-basalt dolerite dykes (frequently mingled with leucogranite material at Pinet and Capon tips) and cross-cutting leucogranitic dykes. Zircon and monazite dating of the Moulin Blanc granite gives a crystallization age of 301 ± 2 Ma. SHRIMP dating on zircons from the leucogranite component of a Pinet composite dyke only reveals zircon core ages of mainly 310 ± 10 Ma (age of migmatization of the host gneiss). Undulating contacts of dolerite dykes within the c. 300 Ma old Camarat granite suggest penecontemporary relationships between the two intrusions. The age interval between the Moulin Blanc granite and the dolerite dykes would thus be very short. The Moulin Blanc pluton is formed by mingling and mixing of melts of granitic and dioritic composition, the latter occurring mainly as microgranular mafic enclaves. Two other types of diorites are also identified in the pluton. The foliated dykes are similar in composition to the Moulin Blanc granite, which confirms their relationship to the main pluton. The Moulin Blanc granite is a typical example of a pluton formed by repeated recharges coming from a deeper magma chamber. Formation of the Camarat dykes is controlled by hydrothermal fluids that are responsible for the non-CHARAC behavior of trace elements. The Pinet and Capon leucogranite components of the dolerite dykes have distinct geochemical signatures, different from the Camarat granite and dykes. The cross-cutting leucogranitic dykes have much geochemical similarities with the Capon granite. The age of similar dykes in the Tanneron Massif supports the contemporaneity of Camarat granite and dolerites. The dolerite geochemistry was deeply modified by alteration processes, but an andesite-basalt composition is still recognizable by using immobile element ratios. In a ?Nd vs. Sri diagram, all rocks plot close to a mixing hyperbola between a depleted mantle component and a crustal component, characteristic of the Variscan crust in the French Massif Central. There is a broad correlation between the NdTDM 2-stage model ages and the degree of fractionation of the rocks. Modeling of dehydration melting in a range of P-T conditions reveals that a variety of lithologies were the source of the Saint-Tropez magmas: high-alumina and alkali-basalt amphibolites, metagraywackes, metapelites and meta-arkoses. These sources were melted almost simultaneously at different levels in the crust. The calculated critical dyke width required to transport the granitic melt by buoyancy is far too large compared to the observed granitic dyke thicknesses. Therefore, tectonic processes and/or melt overpressure must have played a role in the emplacement mechanism. Thermo-mechanical constraints on mixing between mafic and felsic melts suggest that, in the Pinet composite dykes, both melts should have mixed. The observed lack of mixing is interpreted as due to quick cooling. The region was affected by a hot zone at the end of a transpressional regime.

  11. Characterization of Climax granite ground water

    International Nuclear Information System (INIS)

    The Climax ground water fails to match the commonly held views regarding the nature of deep granitic ground waters. It is neither dilute nor in equilibrium with the granite. Ground-water samples were taken for chemical analysis from five sites in the fractured Climax granite at the Nevada Test Site. The waters are high in total dissolved solids (1200 to 2160 mg/L) and rich in sodium (56 to 250 mg/L), calcium (114 to 283 mg/L) and sulfate (325 to 1060 mg/L). Two of the samples contained relatively high amounts of uranium (1.8 and 18.5 mg/L), whereas the other three contained uranium below the level of detection (< 0.1 mg/L). The pH is in the neutral range (7.3 to 8.2). The differences in composition between samples (as seen in the wide range of values for the major constituents and total dissolved solids) suggest the samples came from different, independent fracture systems. However, the apparent trend of increasing sodium with depth at the expense of calcium and magnesium suggests a common evolutionary chemical process, if not an interconnected system. The waters appear to be less oxidizing with depth (+ 410 mV at 420 m below the surface vs + 86 mV at 565 m). However, with Eh measurements on only two samples, this correlation is questionable. Isotopic analyses show that the waters are of meteoric origin and that the source of the sulfate is probably the pyrite in the fracture-fill material. Analysis of the measured water characteristics using the chemical equilibrium computer program EQ3 indicates that the waters are not in equilibrium with the local mineral assemblage. The solutions appear to be supersaturated with respect to the mineral calcite, quartz, kaolinite, muscovite, k-feldspar, and many others

  12. Simulation of bentonite colloid migration through granite

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Full text of publication follows: Colloidal bentonite particles generate at the interface of buffer and host rock in spent nuclear fuel repository due to an erosion process and migrate through granite by the water flow. Stability of these colloids and their migration possibilities have been studied on account of radionuclide transport possibility as colloid could carry adsorbed radionuclides in groundwater through granite. That is why a simulation of bentonite colloid migration in the surrounding of a repository might be requested. According to chemical condition as ionic strength and pH, the colloidal particles coagulate into clusters and that influence the migration of particles. The coagulation kinetics of natural bentonite colloids were experimentally studied in many articles, for example by light scattering techniques. We created a model of coagulation of bentonite colloids and simulation of a chosen experiment with use of the multicomponent reactive transport equation. The coagulation model describes clustering of particles due to attractive van der Waals forces as result of collision of particles due to heat fluctuation and different velocity of particles during sedimentation and velocity gradient of water flow. Next, the model includes influence of repulsive electrostatic forces among colloidal particles leading to stability of particles provided high surface charge of colloids. In the model, each group of clu colloids. In the model, each group of clusters is transported as one solution component and the kinetics of coagulation are implemented as reactions between the components: a shift of particles among groups of particles with similar migration properties, according to size of the clusters of colloids. The simulation of migration of bentonite colloid through granite using the coagulation model was calibrated according to experiment results. On the basis of the simulation, one can estimate the basic processes that occur during bentonite colloid migration. That could be useful for prediction of spent nuclear fuel repository safety with the help of model of bentonite colloid behavior during migration. (authors)

  13. Resaturation of backfilled tunnels in granite

    International Nuclear Information System (INIS)

    Highly compacted bentonite clay is proposed for use as a backfill material around high level waste overpacks to be placed in excavated tunnels in the crystalline bedrock of Northern Switzerland. Initially the bentonite will have a low residual water content and with time the bentonite will resaturate due to the influx of water from the crystalline rock. The time and degree of bentonite saturation are important for safety assessment because of their effect on the corrosion of the waste overpack, on the leaching of the waste matrix, and on the radionuclide transport in the backfill. A three-dimensional, two-phase flow model (FAMOS) is used to quantify the expected resaturation under the conditions outlined above. The time required for complete saturation simulated using FAMOS ranges from less than 100 to more than 1000 years. These results are comparable to the results of diffusive models of bentonite saturation when using a diffusion coefficient of 3x10-10 m2s-1. The time depends on the hydraulic properties of the bentonite as well as the saturated hydraulic conductivity of the crystalline rock. At saturated granite hydraulic conductivities of the order of 10-9 ms-1 the bentonite becomes fully saturated in less than 100 years. For saturated granite hydraulic conductivities of the order of 10-12 ms-1 the bentonite becomes fully saturated in several hundred to over 1000 years. For a given granite hydraulic conductivity the degree of saturation depends on the bentonite capillary pressure versus water saturation characteristic relationships. For high capillary pressures (of the order of 105 kPa) the bentonite saturates relatively quickly; with lower capillary pressures the time for complete saturation increases

  14. Geochemistry of granitic aplite-pegmatite sills and petrogenetic links with granites, Guarda-Belmonte area, central Portugal

    OpenAIRE

    Neiva, Ana Margarida R.; Ramos, João Farinha

    2010-01-01

    Granitic amblygonite-subtype and lepidolite-subtype, aplite-pegmatite sills intruded a biotite>muscovite granite (G1). Two other biotite>muscovite granites (G2 and G3) and a muscovite>biotite granite (G4) crop out in the area. Variation diagrams for major and trace elements of the Variscan rocks show fractionation trends for a) G1 and G4; b) G2, G3 and aplite-pegmatite sills. The two series are confirmed by the two trends defined by major elements of primary muscovite. The sills also contain ...

  15. Characterization of mechanical damage in granite

    Directory of Open Access Journals (Sweden)

    Minh-Phong Luong

    2014-01-01

    Full Text Available This paper aims to illustrate the use of infrared thermography as a non-destructive and non-contact technique to observe the phenomenological manifestation of damage in granite under unconfined compression. It allows records and observations in real time of heat patterns produced by the dissipation of energy generated by plasticity. The experimental results show that this technique, which couples mechanical and thermal energy, can be used for illustrating the onset of damage mechanism by stress concentration in weakness zones.

  16. Relationships between deformation and magmatism in the Pan-African Kandi Shear Zone: Microstructural and AMS studies of Ediacaran granitoid intrusions in central Bénin (West Africa)

    Science.gov (United States)

    Adissin Glodji, L.; Bascou, J.; Yessoufou, S.; Ménot, R.-P.; Villaros, A.

    2014-09-01

    Relationships between the metamorphic basement, granitic intrusions and the Kandi Shear Zone (KSZ) in central Bénin have been investigated using petrological and structural approaches, in order to better understand the space and time parameters of the Pan-African shear deformation and the Ediacaran magmatism. In central Bénin, metamorphic rocks from the KSZ display a steep to vertical N-S trending foliation, a sub-horizontal mineral lineation together with kinematic indicators in agreement with a dextral transcurrent mega-shear zone. Four granitic intrusions (Dassa, Tré, Gobada and Tchetti) show many petrological similarities. They are biotite ± amphibole - ilmenite ± magnetite monzogranites with ferrous and metaluminous I-type features derived from high-K calk-alkaline magma. A fifth intrusion (Fita) is an alkali-feldspar, biotite, magnetite and ilmenite bearing granite crystallized from an alkaline magma. Moreover, high K2O, Zr, Y, Nb and low CaO, MgO and Al2O3 contents together with high (FeOt/MgO) and low LIL/HFS elements ratios suggesting an A-type granite affinity. Microstructural and AMS investigations presented in this paper show (i) solid-state deformation evidence for Dassa pluton and (ii) a magmatic deformation for the Tré, Tchetti, Gobada and Fita granitoids. Foliation in Dassa is parallel to the mesoscopic planar mylonitic foliation of the metamorphic basement. In the Tré, Tchetti, Gobada and Fita granitoids, magmatic textures and magnetic fabrics are coherent with the KSZ activity. These data suggest (i) a syn-kinematic nature for most of the intrusions (Tré, Gobada, Tchetti and Fita), except Dassa which correspond to an earlier event (ii) the succession of high-K calk-alkaline (Dassa, Tré, Gobada, Tchetti) evolves toward alkaline magmas (Fita) during the KSZ strike-slip tectonics. These observations highlight the changing nature of magma composition, magmatic processes and the different sources during KSZ activity in the Bénin Nigerian Shield. These new results suggest that the previous geodynamic interpretations, which assume a post-tectonic emplacement for the Gobada intrusion or an active continental margin setting for most of the late Pan-African (Ediacaran) granites intruded in central Bénin, has to be re-examined.

  17. Cambro-Ordovician Granites in the Araçuaí Belt, in Brazil: snapshots from a late orogenic collapse

    Science.gov (United States)

    De Campos, Cristina P.; Mendes, Júlio Cesar; de Medeiros, Silvia Regina; Ludka, Isabel P.

    2014-05-01

    Along the Brazilian Coast, surrounding the São Francisco Craton and adjacent mobile belts, deep segments of a Neoproterozoic orogen (Araçuaí-West Congo) generated over 120 Ma of successive magmatic episodes of granitic magmatism. The c.630-585 Ma calc-alkaline magmatic arc consists of metatonalite to metagranodiorite, with metadioritic to noritic facies and enclaves. During the syn-collisional and crustal thickening stage (c. 585 to 560 Ma) S-type metagranites have been built by dehydration melting of a diverse package of sediments. Around 545-525 Ma late orogenic crustal remelting formed mostly non-foliated garnet-cordierite leucogranites. In the post-orogenic stage (c. 510-480 Ma) inversely zoned calc-alkaline to alkaline plutons intruded previous units. This work will focus on the youngest post-orogenic magmatism. It will present the state of the art by reviewing structural measurements, detailed mapping of flow patterns and additional geochemical and isotopic data. The architecture of around 10 plutons, ranging from c. 20 to 200 km2 in surface area, unravels deep mushroom- to funnel-like magma chambers and/or conduits. Available data point towards different compositional domains, which are interfingered in complex concentric layers, so that, each pluton depicts a unique internal flow pattern. In the silica-richer structures concentric fragmented or folded layers of granite, in a hybrid K-gabbroic/dioritic matrix, contrast with predominantly homogeneous K-basaltic to gabbroic regions. These may be separated by magmatic shear zones where mixing is enhanced, also resulting in hybrid compositions. Sharp and pillow-like contacts between granitic and K-basaltic rocks locally depict a frozen-in situation of different intrusive episodes. In the silica-poorer plutonic bodies gradational contacts are more frequent and may be the result of convection enhanced diffusion. For all plutons, however, mostly sub-vertical internal contacts between most- and least-differentiated rocks, suggest generation from predominat large magma bodies of variable composition, which crystallized while crossing the middle to lower crust (< 25 km depth). They register snapshots of the interaction dynamics between granitic and noritic/dioritic or syeno-monzonitic and gabbroic magmas with the production of hybrid rock compositions. They provide, therefore, outstanding evidence for a major process of mixing between contrasting magmas, which have been generated from different sources and depths. These are considered to have originated from the orogenic collapse with coeval crustal and mantelic contributions changing in space and time.

  18. Sm/Nd and whole rock geochemistry characterization of the Serra Branca granite: evidence of Archean crust in the Pajeu Paraiba fold belt

    International Nuclear Information System (INIS)

    This work presents and discusses the geochemical and Samarium-Neodymium (SM/Nd) isotopic data for the Serra Branca granite. The Serra Branca granite constitutes one among several brasiliano (=Pan African) intrusions of the transversal zone of the Borborema Tectonica Province, northeastern of Brazil. It is intruded into gneisses and migmatites from the Alto Pajeu Terrain (TAP). The Alto Pajeu Terrain comprises mainly metasediments with minor volcanic contributions and the brasiliano magmatism is restrict to the TAP. After presenting the geological and petrographical considerations, the study shows the Sm-Nd data and concludes that the geochemical and Sm-Nd isotopic signatures of the Serra Branca complex point to a magma generation in the contact zone between an Archean and a Tranzamazonian crust, during decompression, which followed the Brasiliano collisional event

  19. Sm/Nd and whole rock geochemistry characterization of the Serra Branca granite: evidence of Archean crust in the Pajeu Paraiba fold belt

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Ignez de Pinho; Silva Filho, Adejardo F. da [Pernambuco Univ., Recife, PE (Brazil). Dept. de Geologia

    1997-12-31

    This work presents and discusses the geochemical and Samarium-Neodymium (SM/Nd) isotopic data for the Serra Branca granite. The Serra Branca granite constitutes one among several brasiliano (=Pan African) intrusions of the transversal zone of the Borborema Tectonica Province, northeastern of Brazil. It is intruded into gneisses and migmatites from the Alto Pajeu Terrain (TAP). The Alto Pajeu Terrain comprises mainly metasediments with minor volcanic contributions and the brasiliano magmatism is restrict to the TAP. After presenting the geological and petrographical considerations, the study shows the Sm-Nd data and concludes that the geochemical and Sm-Nd isotopic signatures of the Serra Branca complex point to a magma generation in the contact zone between an Archean and a Tranzamazonian crust, during decompression, which followed the Brasiliano collisional event

  20. Aqueous phase transport through granitic rocks

    International Nuclear Information System (INIS)

    Using Scottish granites of UK origin it has been established that : (1) pore connectivity exists over metre distances and does not vary significantly with distance. (2) The formation factor may show an increase by a factor of approx. 2 for thin samples (approx. 1 cm). Since diffusion samples are of this order of thickness, laboratory measurements may be overestimating the diffusion coefficient appropriate for use in migration model calculations by a factor of approx. 2. (3) The effect of confining pressures up to approx. 16 MPa is to reduce diffusion coefficients by 50 to 60%. This implies that diffusion coefficients appropriate to granite at depths of approx. 500 m are approximately a factor of two lower than those obtained in the laboratory. (4) Diffusion rates through weathered fissure surfaces can be significantly greater (up to approx. 200 times) than through 'good' rock and are strongly dependent on the severity of the weathering. No evidence for pore blocking by weathering products was found. (5) Latex colloids having a diameter of 0.312 ?m neither cause pore blocking nor do they penetrate the pore structure. (author)

  1. The 'Granite' collegial mission of dialogue. Report

    International Nuclear Information System (INIS)

    The aim of the 'Granite' collegial mission of dialogue is to inform the French authorities, associations and population about the project of construction of an underground laboratory for the study of the disposal of high level and long-life radioactive wastes in a granitic environment. The aim of the dialogue was not to select a site but to collect the public reactions and advices about such a project. However, such a dialogue has partially failed because of a misunderstanding of the population about the aims of the mission. However, the mission has collected many point of views and questions which are developed in this report. The first and second chapters recall the process of the mission and its progress, while a third chapter stresses on the questions asked by the public and which concern the fear of nuclear wastes and the incompatibility between the disposal of wastes and the socio-economical development of the region concerned. Thanks to the lessons drawn from this experience, the mission has formulated some recommendations (chapter 4) concerning the need for a better information of the population about any topic in relation with the radioactive wastes. Some complementary information is provided in appendixes. (J.S.)

  2. In-situ experiments in granite

    International Nuclear Information System (INIS)

    In-stitu experiments in granite were started in 1983 as a three-year plan of research and development of the experimental techniques to aime at development of a site assessment methodology and to provide the data for the safety assessment of the disposal of radioactive waste. At the test site of granite, an experimental room was excavated for exclusive use and heater test, migration test and corrosion test were performed. The heater test showed good agreement between measured and calculated temperatures in the rock where no fracture was found, however, in fractured zone it showed that the heat transfer by the ground water could not be disregarded. Rock deformation and permiability change were found near the heater in the fractured zone. Nuclide transport along the fracture is much faster than the transport in the rock matrix, besides dispersion in the rock matrix has very important role from the migration test. Corrosion test used sensitized specimens showed that some samples have susceptibilities to stress corrosion cracking after 12 months. (author)

  3. Uranium in the Carnmenellis granite, Cornwall, England

    International Nuclear Information System (INIS)

    Samples from a 30 meter core from the Rosemanowas quarry in the Carnmenellis granite in Cornwall, England were analyzed by induced fission track detection, delayed neutron detection, backscattered electron imaging in a SEM, and energy dispersive x-ray spectrometry. Uranium occurs mainly in: (1) primary accessory minerals; (2) alteration and replacement phases, and (3) microcrack-sealing phases. Zircon, monazite, and apatite are common uraniferous primary accessory minerals. Uraniferous alteration phases include hematite, rutile and pyrolusite. Hematite is a common uraniferous replacement phase. Most sealed microcracks contain uranium. Hematite and pyrolusite are ubiquitous uraniferous crack-sealing phases. Autunite and churchite are occasional uraniferous crack-sealing phases. Whole rock uranium concentrations are extremely variable. High uranium contents result from high percentages of uraniferous primary accessory phases and/or rutile. Hydrothermal activity, such as hematization, can result in depleted whole rock uranium concentrations. Results of this study indicate that uranium and light rare earth elements have been mobilized and redistributed in this section of the Carnmenellis granite by postmagmatic processes. 28 refs., 13 figs. 2 tabs

  4. Crack Damage in Granite: Physical and Mechanical Consequences

    Science.gov (United States)

    Wang, X.-q.; Schubnel, A.; Fortin, J.; Gueguen, Y.; Ge, H.-k.

    2012-04-01

    We investigate the effects of pervasive crack damage on the rupture processes of a fine-grained granite, under triaxial stress, in wet (H20) and dry (argon gas) saturated conditions, at room temperature. Eight samples of La Peyratte granite (a granodiorite with an average grain size of 800 microns) were cored with an initial porosity of

  5. The Serra do Carambei Granite - PR and the uraniferous anomalism

    International Nuclear Information System (INIS)

    The Serra do Carambei Granite forms a pluton relatively homogeneous, covering about 33 km2, cropping out as an elongate retangular body trending NE-SW, being emplaced in the Cunhaporanga Granitoid Complex. Its characteristics indicates a kind of hololeucocratic granite, equigranular, medium to coarse-grained, consisting predominantly of microperthitic alkali-feldspar, quartz and a small amount of biotite (less than 1%), thus being classified as an alaskite. Chemical data allows a classification in the group of granite with high contents of silica (74-76% Wt. SiO2), dominantly alkaline chemism and hypersolvus character, derived from a parental magma under saturated in water with distinguished features of granitoids from the magnetite series and types I and A granites. The pluton shows important chemical variations due to weathering processes. However detailed chemical studies reveal the presence of anomalous concentrations of trace elements such as U, Sn, Nb, Y, Zr, the Serra do Carambei Granite lacks economically important mineralizations because of the absence of well-developed tardi/pos-magmatic processes that could concentrate them. The SW side of the granite is cut by leucocratic rhyolite dykes that show some radiometric anomalies. These rocks, which are highly diferentiated, were emplaced contemporaneously to the Serra do Carambei Granite. Although petrographic and chronological similarities are found between the uraniferous alaskite of Roessing (Namibia) and the Serra do Carambei Granite anyhow it was not possible to establish any lateral continuity with the uranifeous Pan-African Province. (Author)

  6. A Distributed Network Intrusion Detection System with Active Surveillance Agent

    OpenAIRE

    Bin Zeng; Lu Yao; Rui Wang

    2013-01-01

    A distributed network intrusion detection system (IDS) called SA-NIDS is proposed based on the network-based intrusion detection architecture. It includes three basic components, Local Intrusion Detection Monitor (LIDM), Global Intrusion Detection Controller (GIDC), and Surveillance Agent (SA). Basically, the LIDM is used to do packets capturing, packets de-multiplexing, local intrusion detection and intrusion inferring. The GIDC is installed in administration center for communicating and man...

  7. Elderly vs. younger problem drinker 'treatment' and recovery experiences.

    Science.gov (United States)

    Fitzgerald, J L; Mulford, H A

    1992-09-01

    To address the question of whether or not elderly problem drinkers experience any treatment contact discrimination or recovery rate disadvantages, the programme utilization and recovery rate experiences of a representative sample of older and younger persons arrested for drinking and driving (OWI) in Iowa were compared. Subjects were interviewed by phone or mail shortly after their OWI arrest and then again approximately 12 months later. Younger persons (18-54 years old) were compared with elderly persons (55 and over and 65 and over). The elderly subjects were also dichotomized as early onset (at least one problem drinking indicator occurred prior to age 55) or late onset (all problem drinking indicators occurred at age 55 or later). The elderly were as likely as, or more likely than, their younger counterparts to make a treatment contact, to remain in treatment and to recover. PMID:1327336

  8. Eocene Granitic Magmatism in NW Anatolia (Turkey) revisited: New implications from comparative zircon SHRIMP U-Pb and 40Ar-39Ar geochronology and isotope geochemistry on magma genesis and emplacement

    Science.gov (United States)

    Altunkaynak, ?afak; Sunal, Gürsel; Aldanmaz, Ercan; Genç, Can ?.; Dilek, Y?ld?r?m; Furnes, Harald; Foland, Kenneth A.; Yang, Jingsui; Y?ld?z, Merve

    2012-12-01

    During the Eocene, the northern Neo-Tethys suture zone and immediately adjacent areas in NW Turkey were loci of emplacement of a number of granitoid plutons with age relations and geochemical signatures indicative of magma generation in association with plate convergence. Discrete granitoid plutons of Eocene age in this region are exposed mainly in two distinct belts within and north of the northern Neo-Tethys suture zone. We report new SHRIMP U-Pb zircon and 40Ar/39Ar geochronology along with Sr-Nd isotope data from the granitoids in order to constrain their melt source(s), cooling history, and tectono-magmatic evolution with respect to the Early Cenozoic collisional tectonics of the region. Ranging in composition from diorite to granite, the plutons are largely represented by medium- to high-K calc-alkaline, I-type granites accompanied by minor amounts of shoshonitic rocks with syenite compositions and mafic microgranular enclaves in some of the plutons. In terms of trace element systematics the granitoids and the associated enclaves from the entire Eocene suite display close similarities to magmas from subduction-related or active continental margin settings, characterized by significant enrichment in LILE/HFSE relative to MORB. The rocks display significantly heterogeneous distributions of radiogenic isotopes with 87Sr/86Sr and 143Nd/144Nd ranging from 0.705824 to 0.708363 and from 0.512384 to 0.512718 respectively, suggesting multi-component melt interaction in their genesis. The granitoids from the southern and northern belts yielded zircon SHRIMP U-Pb ages of 52.8 ± 1.8 to 45.41 ± 0.34 Ma and 47.02 ± 0.82 to 36.79 ± 0.67 Ma, respectively, indicating overlapping emplacement ages, with some relatively younger ages from the northern belt. 40Ar/39Ar dating of biotite and hornblende also yielded similarly overlapping cooling ages (51.8 ± 0.1 to 44.9 ± 0.2 Ma and 45.3 ± 0.1 to 36.0 ± 0.1 Ma, respectively). Our combined geochronological data from the co-genetic zircon, and hornblende and biotite separates reveals rapid cooling of the plutons immediately after emplacement, which can readily be attributed to rapid uplift starting at ˜ 53 Ma. Unlike the intrusions in the southern belt, some of the granitoids in the northern belt contain inherited zircons of older ages, possibly reflecting more pronounced effects of crustal input in their genesis. On the basis of new geochemical and geochronological data, we infer that melt generation to produce the granitic plutons shortly after subduction waned in the region is most probably related to abrupt thermal weakening of the orogenic lithosphere due either to slab break-off or partial removal of a thermal boundary layer between lithosphere and asthenosphere that led to syn-convergent extension and collapse in the overriding plate, resulting in the onset of the development of the Aegean extensional province.

  9. Obesity and sexual dysfunction in younger Danish men

    DEFF Research Database (Denmark)

    Andersen, Ingelise; Heitmann, Berit L

    2008-01-01

    INTRODUCTION: Proportion of populations that are overweight and obese are on the rise and generally affecting more than 50% of the adult Western male population. It is, therefore, of interest to look at possible associations between obesity and sexual function in a homogeneous population. AIM: To examine a possible association between sexual disorders (erectile dysfunction, ejaculatory disorders, and sexual desire disorders) and obesity among younger men born and living in Denmark. METHODS: A community-based cross-sectional study of sexual health among Danish younger men. Questionnaires were mailed to 3,300 men, aged 20-45 years and divided into six 5-year age cohorts. Odds ratios were calculated using logistic regression modeling. In total, 863 men (26%) responded anonymously. A similar set of data from 600 older men aged 50-75 years and from same community was used for comparison. MAIN OUTCOME MEASURES: The associations between self-reported erectile, ejaculatory and desire disorders, and body mass index(BMI) were examined, stratified by age group and smoking status. RESULTS: The material was found to be generally representative of the Danish population of men of similar age in regard to height, weight, smoking status, and alcohol consumption. Erectile dysfunction (ED) was more prevalent among these younger and older men with higher BMI, but only significant among men 20-45 years old, with an odds ratio of 2.74 (95% confidence interval 1.1-6.8). The prevalence of ED was higher among the younger obese nonsmokers than obese smokers. Premature ejaculation, retarded ejaculation, and sexual desire disorders were all unrelated to overweight or obesity. CONCLUSION: Obesity (BMI > or = 30 kg/m(2)) seems associated with ED among younger men aged 20-45 years. Health programs directed toward preventing obesity in younger men may benefit from informing about an almost three-fold occurrence of erectile dysfunction associated with obesity.

  10. The Younger Dryas age of the Salpausselkä moraines in Finland

    Directory of Open Access Journals (Sweden)

    Joakim Donner

    2010-12-01

    Full Text Available The late-glacial Younger Dryas Stadial, as defined over seventy years ago in Denmark, was compared with the withdrawal of the Scandinavian ice sheet and correlated in Finland in 1951 with the formation of the Salpausselkä moraines. Since then a great number of studies of Younger Dryas has eventually led to its definition in the Event Stratigraphy for the North Atlantic region, based on the oxygen isotope stratigraphy in the Greenland ice-core NGRIP. The age of the Younger Dryas / Preboreal boundary, the beginning of the Holocene, is in this stratigraphy dated at 11 653 yr. BP, an age close to the age deter-mined for the drainage of the Baltic Ice Lake and the beginning of the rapid retreat of the ice margin from Salpausselkä II in Finland and the corresponding Billingen moraine in Sweden. This leads to the conclusion that the Salpausselkä moraines Ss I and Ss II were formed during Younger Dryas, according to the revised varve chronology between c. 12 260 and c. 11 600 yr. BP. The third Salpausselkä, Ss III, was according to this dating formed in early Holocene. After the 1950s, when the Salpausselkä moraines were dated as having been formed during the Younger Dryas Stadial, the ages of the boundaries of Younger Dryas changed as a result of revisions of the time scales of varved clays and the use of radiocarbon ages and their calibrations. As a result of these changes the age of the two main Salpausselkä moraines, Ss I and Ss II, is older than assumed 60 years ago on the basis of the varve chronology.

  11. Geophysical Studies of Irish Granites Using Magnetotelluric and Gravity Data

    Science.gov (United States)

    Farrell, T. F.; Muller, M. R.; Rath, V.; Feely, M.; Hogg, C.

    2014-12-01

    We present results of on-going geophysical studies of Caledonian radiothermal granite bodies in Ireland, which are being undertaken to investigate the volumetric depth extent and structural features of these granites. During three field seasons, magnetotelluric (MT) and audio-magnetotelluric (AMT) data were acquired at 156 sites targeting three separate granite bodies. These studies will contribute to a crustal-scale investigation of the geothermal energy potential of the granites and their contribution to the thermal field of the Irish crust. Across the calc-alkaline Galway granite, located on the Irish west coast, MT and AMT data were acquired at 75 sites distributed in a grid. Preliminary 3D inversion reveals the presence of a resistor, thickest beneath the central block of the granite where it extends to depths of 11 - 12 km. The greater depth of the resistor beneath the central block is in contrast to previous thinking that proposed the central block granites to have shallower depth extent than those of the western block, based on Bouguer anomaly maps of the area in which the western block exhibited a more pronounced negative Bouguer anomaly than the central block. At the S-type Leinster granite, in eastern Ireland and to the south of Dublin, MT and AMT data were acquired along two profiles (LGN - 27 sites and LGS - 32 sites). Preliminary 1D inversions of AMT data along profile LGN show the Northern Units of the Leinster granite to extend to a depth of 4.5 km and the Lugnaquilla pluton extending to 2.5 km depth. MT and AMT data were acquired at 22 sites along a profile across the buried Kentstown granite, 35 km to the NW of Dublin. The Kentstown granite was intersected by two mineral exploration boreholes at depths of 492 m and 663 m. Preliminary 2D inversions do not yet satisfactorily resolve the top of the buried granite. Inversion of MT and AMT data is continuing, with the electrical conductivity structures revealed by these inversions being used to constrain inversions of gravity data. The integration of MT and gravity data will provide an insight into the potential density distribution within the resistors associated with the granites and whether the granites, likely to have elevated heat-production (HP), are underlain by electrically resistive but denser, more mafic bodies, likely to be associated with lower HP.

  12. IRETHERM: The geothermal energy potential of Irish radiothermal granites

    Science.gov (United States)

    Farrell, Thomas; Jones, Alan; Muller, Mark; Feely, Martin; Brock, Andrew; Long, Mike; Waters, Tim

    2014-05-01

    The IRETHERM project is developing a strategic understanding of Ireland's deep geothermal energy potential through integrated modelling of new and existing geophysical and geological data. One aspect of IRETHERM's research focuses on Ireland's radiothermal granites, where increased concentrations of radioelements provide elevated heat-production (HP), surface heat-flow (SHF) and subsurface temperatures. An understanding of the contribution of granites to the thermal field of Ireland is important to assessing the geothermal energy potential of this low-enthalpy setting. This study focuses on the Galway granite in western Ireland, and the Leinster and the buried Kentstown granites in eastern Ireland. Shallow (granites as part of a 1980's geothermal project. These studies yielded HP = 2-3 ?Wm-3 and HF = 80 mWm-2 at the Sally Gap borehole in the Northern Units of the Leinster granite, to the SW of Dublin. In the Galway granite batholith, on the west coast of Ireland, the Costelloe-Murvey granite returned HP = 7 ?Wm-3 and HF = 77 mWm-2, measured at the Rossaveal borehole. The buried Kentstown granite, 35 km NW of Dublin, has an associated negative Bouguer anomaly and was intersected by two mineral exploration boreholes at depths of 660 m and 490 m. Heat production is measured at 2.4 ?Wm-3 in core samples taken from the weathered top 30 m of the granite. The core of this study consists of a program of magnetotelluric (MT) and audio-magnetotelluric (AMT) data acquisition across the three granite bodies, over three fieldwork seasons. MT and AMT data were collected at 59 locations along two profiles over the Leinster granite. Preliminary results show that the northern units of the Leinster granite (40 km SW of Dublin) extend to depths of 2-5 km. Preliminary results from the southern profile suggest a greater thickness of granite to a depth of 6-9 km beneath the Tullow pluton, 75 km SW of Dublin. Over the Galway granite, MT and AMT data have been collected at a total of 75 sites (33 consist of only AMT data acquisition, with both MT and AMT recorded at the remaining 42). Preliminary results show a deep resistor extending to depths of 15-20 km beneath the central block, with the resistive upper layer extending to depths of 3.5-7 km west of the Shannawona fault, a major structure that cuts the batholith. MT and AMT data acquired along a profile at 22 locations over the Kentstown granite suggests that this buried granite is at a depth of 400 m beneath the centre of the gravity anomaly. The MT and AMT data will be integrated with gravity and seismic refraction data (in the case of the Leinster granite) to identify deeply penetrating faults, which may provide conduits for hydrothermal fluids, and to produce a robust estimation of the volumetric extent of the granites, which is crucial in defining their geothermal energy potential. Thermal conductivity and geochemical data will be incorporated to constrain the heat contribution of granites to the Irish crust.

  13. Q-ROUTING AND INTRUSION DETECTION

    OpenAIRE

    Ojha, D. B.

    2011-01-01

    In this paper, we showed the procedure for solution of routing problem and intrusion detection. Our approach consist Q-routing and verification for authorization in MANET. Keywords: Authentication, Intrusion Detection System (IDS),Mobile Ad hoc Network (MANET),Monitoring node, Security.

  14. Intrusion-Aware Alert Validation Algorithm for Cooperative Distributed Intrusion Detection Schemes of Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Young-Jae Song

    2009-07-01

    Full Text Available Existing anomaly and intrusion detection schemes of wireless sensor networks have mainly focused on the detection of intrusions. Once the intrusion is detected, an alerts or claims will be generated. However, any unidentified malicious nodes in the network could send faulty anomaly and intrusion claims about the legitimate nodes to the other nodes. Verifying the validity of such claims is a critical and challenging issue that is not considered in the existing cooperative-based distributed anomaly and intrusion detection schemes of wireless sensor networks. In this paper, we propose a validation algorithm that addresses this problem. This algorithm utilizes the concept of intrusion-aware reliability that helps to provide adequate reliability at a modest communication cost. In this paper, we also provide a security resiliency analysis of the proposed intrusion-aware alert validation algorithm.

  15. Intrusion Preventing System using Intrusion Detection System Decision Tree Data Mining

    Directory of Open Access Journals (Sweden)

    Syurahbil

    2009-01-01

    Full Text Available Problem statement: To distinguish the activities of the network traffic that the intrusion and normal is very difficult and to need much time consuming. An analyst must review all the data that large and wide to find the sequence of intrusion on the network connection. Therefore, it needs a way that can detect network intrusion to reflect the current network traffics. Approach: In this study, a novel method to find intrusion characteristic for IDS using decision tree machine learning of data mining technique was proposed. Method used to generate of rules is classification by ID3 algorithm of decision tree. Results: These rules can determine of intrusion characteristics then to implement in the firewall policy rules as prevention. Conclusion: Combination of IDS and firewall so-called the IPS, so that besides detecting the existence of intrusion also can execute by doing deny of intrusion as prevention.

  16. Chemical characteristics of zircon from A-type granites and comparison to zircon of S-type granites.

    Czech Academy of Sciences Publication Activity Database

    Breiter, Karel; Lamarão, C. N.; Krás Borges, R. M.; Dall'Agnol, R.

    1192/195, April (2014), s. 208-225. ISSN 0024-4937 Institutional support: RVO:67985831 Keywords : zircon * A-type granites * S-type granites * Wiborg batholith * Brazil * Krušné hory/Erzgebirge Subject RIV: DD - Geochemistry Impact factor: 3.654, year: 2013

  17. U-Th-Pb age in hydrothermal monazite applied in geochronological tin mineralization from Greisen zone of the Palanqueta granitic system, Bom Futuro deposit, Rondonia, Brazil

    International Nuclear Information System (INIS)

    The ages of hydrothermal events responsible for tin mineralization in the granitic systems from the Rondonia Tin Province are poorly defined so far. Available K-Ar dating in Li-micas of greisens and veins yielded values around 965 Ma, younger than the late mineralized granites ages, around 990 Ma. Electron microprobe U, Th and Pb dating of hydrothermal monazite from the greisen zones of the Palanqueta plutonic system, Bom Futuro tin deposit, yielded an age of 997±48 Ma. Considering that: the K-Ar method is influenced by increasing temperature; critical temperature of Ar retention in micas is 300 deg C; and fluid inclusions and ae 18O studies indicate, respectively, trapping temperature above 300 deg C and cassiterite crystallization temperature above 400 deg C, we suggest that the K-Ar dating in micas from Rondonia tin deposits are indicative of cooling and closure of the hydrothermal systems. Therefore, ages obtained from U-Th-Pb data in hydrothermal monazite from greisen can be considered a good reference for the tin ore formation in the Bom Futuro deposit, associated with late to post-magmatic processes, and coeval with the end of crystallization of albite granite in the Palanqueta granitic system. (author)

  18. Total exploitation of an ornamental granite quarry

    Directory of Open Access Journals (Sweden)

    Taboada, J.

    2005-09-01

    Full Text Available In this paper we propose a methodology to estimate the recovery percentage for each of the products which can be obtained from the exploitation of an ornamental granite quarry: block, semiblock, masonry-transverse stone, and the smaller materials that can be used to obtain construction aggregates. This methodology ensures that quarry exploitation is exhaustive, thereby minimising the production of spoils and the consequent negative impact on the environment. The analysis is based on a detailed and exhaustive compilation of discontinuity data from the research fronts, which are then interpreted statistically and projected over the three weakness planes that are a particular feature of ornamental granite deposits. Using this information, and bearing in mind the minimum commercially viable sizes for each kind of granite, the corresponding recovery rates are calculated for each material in each plane. The results are then integrated using spatial techniques, and the result is an evaluation of quarry contents with a view to total exploitation. This methodology was applied to a quarry in the opening phase in order to carry out an a priori assessment of the economic feasibility of the quarry.

    En este trabajo se propone una metodología para estimar el porcentaje de recuperación de cada uno de los productos que se pueden obtener en la explotación de una cantera de granito ornamental: bloque, semibloque, manpostería y per piaños, y material restante destinado a la obtención de áridos. De esta manera se logra un aprovechamiento integral de la cantera, evitándose la generación de estériles y el subsiguiente impacto ambiental producido por éstos. La metodología de análisis se basa en la recopilación detallada y exhaustiva de datos de discontinuidades en los frentes de investigación, que se interpretan estadísticamente y se proyectan sobre los tres planos de debilidad propios del granito ornamental. Con esta información, y las dimensiones mínimas comerciales de referencia para cada tipo de material, se realiza el cálculo de las recuperaciones correspondientes de cada material en cada plano y los resultados de recuperación sobre estos tres planos se integran mediante técnicas espaciales; obteniéndose la evaluación de los recursos en la cantera para su aprovechamiento integral. La metodología ha sido aplicada a una cantera en fase de apertura para realizar una valoración inicial de su viabililidad económica.

  19. IRETHERM: Magnetotelluric Assessment of Geothermal Energy Potential of Hydrothermal Aquifer, Radiothermal Granite and Warm Spring Targets in Ireland

    Science.gov (United States)

    Jones, Alan G.; Muller, Mark; Fullea, Javier; Vozar, Jan; Blake, Sarah; Delhaye, Robert; Farrell, Thomas

    2013-04-01

    IRETHERM (www.iretherm.ie) is an academic-government-industry, collaborative research project, funded by Science Foundation Ireland, with the overarching objective of developing a holistic understanding of Ireland's low-enthalpy geothermal energy potential through integrated modelling of new and existing geophysical and geological data. With the exception of Permo-Triassic basins in Northern Ireland, hosting geothermal aquifers of promising but currently poorly-defined potential, rocks with high primary porosity have not been identified elsewhere. Whether any major Irish shear zones/faults might host a geothermal aquifer at depth is also unknown, although clusters of warm-springs in the vicinity of two major shear zones are promising. IRETHERM's objectives over a four-year period are to: (i) Develop multi-parameter geophysical modelling and interpretation software tools that will enhance our ability to explore for and assess deep aquifers and granitic intrusions. (ii) Model and understand temperature variations in the upper-crust. Firstly, by building a 3-D model of crustal heat-production based on geochemical analysis of surface, borehole and mid- to lower-crustal xenolith samples. Secondly, by modelling, using a fully self-consistent 3-D approach, observed surface heat-flow variation as a function of variation in the structure and thermal properties of the crust and lithosphere, additionally constrained by surface elevation, geoid, gravity, seismic and magnetotelluric (MT) data. (iii) Test a strategic set of eight "type" geothermal targets with a systematic program of electromagnetic surveys (MT, CSEM) across ten target areas. During 2012, IRETHERM collected over 220 MT/AMT sites in the investigation of a range of different geothermal target types. Here we present preliminary electrical resistivity modelling results for each target investigated and discuss the implications of the models for geothermal energy potential: 1. Rathlin Basin The only sedimentary strata in Ireland known to provide reliable primary porosity, supporting deep hydrothermal aquifers, are found in the Triassic Sherwood Sandstone Group and in the upper-Permian, preserved in several basins in Northern Ireland. Our survey over the Rathlin Basin aims to map the geometry of these strata at depth and assess their porosity and permeability characteristics. 2. Kilbrook warm spring. Kilbrook warm spring is characterised by the warmest spring waters in Ireland (24.8°C) and highest Total Dissolved Solids concentration. Our high-resolution AMT survey over this occurrence aims to image the subsurface fluid conduit systems that bring these waters to surface. 3. Leinster and Galway granites Many of Ireland's exposed granites are associated with high radioactive element concentrations, high radiogenic heat production (HP) values and elevated surface heat-flow (SHF). Surveys over two of these granites - the Leinster granite (SHF: 80 mWm-2, HP: 2-3 µWm-3) and the Galway granite (SHF: 65-77 mWm-2, HP: 4-7 µWm-3) - aim to define the geometry, volume and local/regional heating effect of the granites and assess their suitability for energy provision using EGS. The models will also be assessed for indications of naturally occurring hydrothermal aquifers associated with either major faults that cross-cut the granites or the granite-country rock contacts.

  20. Media use by children younger than 2 years.

    Science.gov (United States)

    Brown, Ari

    2011-11-01

    In 1999, the American Academy of Pediatrics (AAP) issued a policy statement addressing media use in children. The purpose of that statement was to educate parents about the effects that media--both the amount and the content--may have on children. In one part of that statement, the AAP recommended that "pediatricians should urge parents to avoid television viewing for children under the age of two years." The wording of the policy specifically discouraged media use in this age group, although it is frequently misquoted by media outlets as no media exposure in this age group. The AAP believed that there were significantly more potential negative effects of media than positive ones for this age group and, thus, advised families to thoughtfully consider media use for infants. This policy statement reaffirms the 1999 statement with respect to media use in infants and children younger than 2 years and provides updated research findings to support it. This statement addresses (1) the lack of evidence supporting educational or developmental benefits for media use by children younger than 2 years, (2) the potential adverse health and developmental effects of media use by children younger than 2 years, and (3) adverse effects of parental media use (background media) on children younger than 2 years. PMID:22007002

  1. CDC Vital Signs: Preventing Pregnancies in Younger Teens

    Science.gov (United States)

    ... parents. Parents, guardians, and caregivers can Talk with teens about sex , including: Normal sexual development, and how and when ... technology (e.g., cell phones, computers, tablets). Younger teens can ... pressure to start having sex until they are older. Talk openly about sexual ...

  2. Atomoxetine Treatment for ADHD: Younger Adults Compared with Older Adults

    Science.gov (United States)

    Durell, Todd; Adler, Lenard; Wilens, Timothy; Paczkowski, Martin; Schuh, Kory

    2010-01-01

    Objective: Atomoxetine is a nonstimulant medication for treating child, adolescent, and adult ADHD. This meta-analysis compared the effects in younger and older adults. Method: A post hoc analysis was conducted using data from two double-blind, placebo-controlled clinical trials. Data from patients aged 18-25 years were compared with data from…

  3. The Experiences of the Younger Supervisor: Implications for Organizations

    Science.gov (United States)

    Hanson, Lea

    2012-01-01

    With four generations in today's workforce, roles are being redefined to include a growing number of younger supervisor/older subordinate relationships, referred to as the intergenerational dyad. What current and limited literature exists about the intergenerational dyad exclusively addresses the issues of generational workplace differences…

  4. On Younger Stakeholders and Decommissioning of Nuclear Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Tyszkiewicz, Bogumila; Labor, Bea

    2009-08-15

    In modern democratic countries, information sharing and effective and open communication concerning dismantling and decommissioning of of nuclear facilities as well as the management of nuclear waste are essential for the task to build the confidence required for any further development of nuclear energy. At the same time, it is often perceived that all decision making processes about nuclear energy policies are probably increasingly influenced by public opinion. Nuclear and radiation safety Authorities have a clear role in this regard to provide unbiased information on any health and safety related issues. In order to meet this need, it is necessary for Authorities and others to understand the values and opinions of the citizens, and especially the younger ones. They hold the key to the future at the same time as their perspective on these issues is the least understood. The need of greater public participation in decision making is becoming increasingly recognised the scientific as well as the political community. Many activities are carried out in order to stimulate to higher levels of public involvement in decision making in this active research area. Younger citizens is a stakeholder group that is often excluded in decision- making processes. The existence of large gaps between the involvement of older and younger stakeholders in decision making processes needs to be addressed, since such imbalances might otherwise lead to unequal opportunities between generations and limit the future consumption level of the coming generations. Another demanding task for the present generation is to assure that appropriate financial resources are injected into the Swedish Nuclear Waste Fund. It will thereby be possible for coming generations to undertake efficient measures in the decommissioning and dismantling of older nuclear facilities. To undertake such measures in line with the environmental and health codex is essential. An appropriate balance in this regard must be based on a proper understanding of the values and value functions of younger citizens. Such information must thus be an integral part of the knowledge base to be used when plans and processes are being developed for dismantling and decommissioning of nuclear power plants and other older nuclear facilities. In the present project, empirical data have been collected and compiled in a survey of the values of younger citizens with regard to decommissioning and dismantling of older nuclear facilities. The survey constitutes a stratified sample from three towns in Poland. They are Lublin, Olsztyn and Gdansk. A total of 780 students in the age group 14-19 years participated in the Survey. The results are compared to those from a similar study in the County of Kalmar in Sweden in the year 2006. The results include some major lesson learned. These may be summarised as follows: - Younger citizens tend to base their values regarding decommissioning on safety, and environmental aspects. Aspects like future economic growth and technological processes are less influential on the values. - Younger citizens tend to express a lack of information and debate as a basis of their value functions. Likewise, they tend to express interest in the topic and are open to become more included in the processes. - Younger citizens have suggestions on how more information can be made accessible to the general public. - Younger citizens need to be better included in the stakeholder process. This can be achieved by allowances from the Swedish Nuclear Waste Fund to support groups of younger citizens to follow the Swedish process of research, development and demonstration of a concept for the management of spent nuclear fuel. Less than fully accessible information campaigns about nuclear power and associated nuclear waste may result in differences in confidence levels between different groups of stakeholders. By finding out more about the values of different stakeholders it will be possible for the Swedish Radiation Safety Authority as well as for Society as a whole to enhance the possibility t o de

  5. On Younger Stakeholders and Decommissioning of Nuclear Facilities

    International Nuclear Information System (INIS)

    In modern democratic countries, information sharing and effective and open communication concerning dismantling and decommissioning of of nuclear facilities as well as the management of nuclear waste are essential for the task to build the confidence required for any further development of nuclear energy. At the same time, it is often perceived that all decision making processes about nuclear energy policies are probably increasingly influenced by public opinion. Nuclear and radiation safety Authorities have a clear role in this regard to provide unbiased information on any health and safety related issues. In order to meet this need, it is necessary for Authorities and others to understand the values and opinions of the citizens, and especially the younger ones. They hold the key to the future at the same time as their perspective on these issues is the least understood. The need of greater public participation in decision making is becoming increasingly recognised the scientific as well as the political community. Many activities are carried out in order to stimulate to higher levels of public involvement in decision making in this active research area. Younger citizens is a stakeholder group that is often excluded in decision- making processes. The existence of large gaps between the involvement of older and younger stakeholders in decision making processes needs to be addressed, since such imbalances might otherwise lead to unequal opportunities between generations and limit the future consumption level of the coming generations. Another demanding task for the present generation is to assure that appropriate financial resources are injected into the Swedish Nuclear Waste Fund. It will thereby be possible for coming generations to undertake efficient measures in the decommissioning and dismantling of older nuclear facilities. To undertake such measures in line with the environmental and health codex is essential. An appropriate balance in this regard must be based on a proper understanding of the values and value functions of younger citizens. Such information must thus be an integral part of the knowledge base to be used when plans and processes are being developed for dismantling and decommissioning of nuclear power plants and other older nuclear facilities. In the present project, empirical data have been collected and compiled in a survey of the values of younger citizens with regard to decommissioning and dismantling of older nuclear facilities. The survey constitutes a stratified sample from three towns in Poland. They are Lublin, Olsztyn and Gdansk. A total of 780 students in the age group 14-19 years participated in the Survey. The results are compared to those from a similar study in the County of Kalmar in Sweden in the year 2006. The results include some major lesson learned. These may be summarised as follows: - Younger citizens tend to base their values regarding decommissioning on safety, and environmental aspects. Aspects like future economic growth and technological processes are less influential on the values. - Younger citizens tend to express a lack of information and debate as a basis of their value functions. Likewise, they tend to express interest in the topic and are open to become more included in the processes. - Younger citizens have suggestions on how more information can be made accessible to the general public. - Younger citizens need to be better included in the stakeholder process. This can be achieved by allowances from the Swedish Nuclear Waste Fund to support groups of younger citizens to follow the Swedish process of research, development and demonstration of a concept for the management of spent nuclear fuel. Less than fully accessible information campaigns about nuclear power and associated nuclear waste may result in differences in confidence levels between different groups of stakeholders. By finding out more about the values of different stakeholders it will be possible for the Swedish Radiation Safety Authority as well as for Society as a whole to enhance the possibility t o de

  6. Inclusões fluidas crepitadas, fluidos hipersalinos e aquo-carbônicos em quartzo associado a rochas micáceas no Granito Xinguara - Terreno Granito-Greenstone de Rio Maria, PA / Decrepitated fluid inclusions, aqueous-carbonic and hypersaline fluids in quartz associated to micaceous rocks in the Xinguara Granite - Rio Maria Granite - Greenstone terrain, Pará, Brazil

    Scientific Electronic Library Online (English)

    Marcelo Leopoldo, Weber; Luiz Henrique, Ronchi; Fernando Jacques, Althoff; Albano Antônio da Silva, Leite; Roberto, Dall' Agnol; Kazuo, Fuzikawa.

    2008-03-01

    Full Text Available As rochas micáceas encontradas no Granito Xinguara, terreno Granito-Greenstone de Rio Maria, Pará, são compostas por muscovita e clorita com níveis de quartzo intercalados, que formam uma xistosidade bem desenvolvida. Essa xistosidade é cortada por veios de quartzo. Ambas as gerações de quartzo apre [...] sentam os mesmos tipos de inclusões fluidas em halos ou trilhas secundárias de composições variadas entre aquosas, aquo-carbônicas e saturadas em torno de grandes inclusões primárias crepitadas ou em trilhas transgranulares secundárias. A grande variação de temperaturas de homogeneização, a alta salinidade, as evidências de estrangulamento e a existência das inclusões crepitadas permitem supor forte influência de alterações pós-formacionais e reequilíbrio relacionados à intrusão do granito. Essas rochas foliadas são, portanto, enclaves metassedimentares afetados por fluidos graníticos hipersalinos aquo-carbônicos. Abstract in english The micaceous rocks occurring in the Xinguara Granite, Rio Maria Granite-Greenstone terrain, Pará State, Brazil, are composed of muscovite and chlorite with quartz levels intercalated forming a well developed schistosity. This schistosity is cut by quartz veins. Both quartz generations show the same [...] aqueous, aqueous-carbonic and halite-bearing fluid inclusions either in secondary inclusions halos and trails surrounding decrepitated primary fluid inclusions or in transgranular secondary trails. A wide variation of homogenization temperatures, high salinity, necking down and the decrepitated inclusions existence indicates strong influence of post-formational alteration and reequilibration linked to the granite intrusion. These foliated rocks are metasedimentary enclaves affected by late hypersaline aqueous-carbonic granitic fluids.

  7. Inclusões fluidas crepitadas, fluidos hipersalinos e aquo-carbônicos em quartzo associado a rochas micáceas no Granito Xinguara - Terreno Granito-Greenstone de Rio Maria, PA Decrepitated fluid inclusions, aqueous-carbonic and hypersaline fluids in quartz associated to micaceous rocks in the Xinguara Granite - Rio Maria Granite - Greenstone terrain, Pará, Brazil

    Directory of Open Access Journals (Sweden)

    Marcelo Leopoldo Weber

    2008-03-01

    Full Text Available As rochas micáceas encontradas no Granito Xinguara, terreno Granito-Greenstone de Rio Maria, Pará, são compostas por muscovita e clorita com níveis de quartzo intercalados, que formam uma xistosidade bem desenvolvida. Essa xistosidade é cortada por veios de quartzo. Ambas as gerações de quartzo apresentam os mesmos tipos de inclusões fluidas em halos ou trilhas secundárias de composições variadas entre aquosas, aquo-carbônicas e saturadas em torno de grandes inclusões primárias crepitadas ou em trilhas transgranulares secundárias. A grande variação de temperaturas de homogeneização, a alta salinidade, as evidências de estrangulamento e a existência das inclusões crepitadas permitem supor forte influência de alterações pós-formacionais e reequilíbrio relacionados à intrusão do granito. Essas rochas foliadas são, portanto, enclaves metassedimentares afetados por fluidos graníticos hipersalinos aquo-carbônicos.The micaceous rocks occurring in the Xinguara Granite, Rio Maria Granite-Greenstone terrain, Pará State, Brazil, are composed of muscovite and chlorite with quartz levels intercalated forming a well developed schistosity. This schistosity is cut by quartz veins. Both quartz generations show the same aqueous, aqueous-carbonic and halite-bearing fluid inclusions either in secondary inclusions halos and trails surrounding decrepitated primary fluid inclusions or in transgranular secondary trails. A wide variation of homogenization temperatures, high salinity, necking down and the decrepitated inclusions existence indicates strong influence of post-formational alteration and reequilibration linked to the granite intrusion. These foliated rocks are metasedimentary enclaves affected by late hypersaline aqueous-carbonic granitic fluids.

  8. Petrogenesis of Late Cretaceous I-type granites in the southern Yidun Terrane: New constraints on the Late Mesozoic tectonic evolution of the eastern Tibetan Plateau

    Science.gov (United States)

    Wang, Xin-Song; Hu, Rui-Zhong; Bi, Xian-Wu; Leng, Cheng-Biao; Pan, Li-Chuan; Zhu, Jing-Jing; Chen, You-Wei

    2014-11-01

    The collision between the Lhasa and Qiangtang terranes, prior to the Indo-Asian collision, is a critical aspect in terms of development of the Tibetan Plateau. It has been demonstrated that the occurrence of the Late Cretaceous granites (110-80 Ma) in the Yidun Terrane, eastern Tibetan Plateau (ETP) associates with the Lhasa-Qiangtang collision. The Xiuwacu Late Cretaceous pluton in the southern Yidun Terrane, consists three phases including biotite granitic porphyry (phase 1), monzogranite (phase 2), and alkali-feldspar leucogranite (phase 3), which have zircon U-Pb ages ranging from 85.5 Ma to 84.4 Ma. All these three phases are metaluminous or slightly peraluminous granites (A/CNK = 0.96-1.07), with high SiO2 (70.0-76.0 wt.%), K2O + Na2O (7.5-10.7 wt.%), and Ga/Al (2.5-4.7), and relatively low CaO (0.39-1.67 wt.%), MgO (0.01-0.57 wt.%), and P2O5 (0.01-0.17 wt.%). The granites are enriched in light rare earth elements (LREEs), Rb, Th, U and Ta, but depleted in heavy REEs (HREEs), Ba, Sr, P, and Ti, with significantly negative Eu anomalies (Eu/Eu* = 0.24-0.59). Comparing to classic A-type granites, these samples present higher Sr (10.1-256 ppm, mostly > 100 ppm) and lower FeO*/MgO ratios (1.2-9.9) and Zr + Nb + Ce + Y (248-483 ppm, mostly mafic-intermediate lower continental crust. Besides, variable zircon ?18O values (5.9‰ to 8.4‰, partly mafic microgranular enclaves (MMEs) within the granites probably indicate a contribution of mantle components. Although the Xiuwacu Late Cretaceous intrusions show higher SiO2 values and lower Sr/Y ratios comparing to other three high Sr/Y I-type intrusions (Relin, Hongshan, and Tongchanggou) in the southern Yidun Terrane, similar (87Sr/86Sr)i, ?Nd(t), ?Hf(t), and ?18O contents in all of these four intrusions point to a common source. We propose that both the Xiuwacu intrusions and the other three intrusions in the southern Yidun Terrane were generated under a late- or post-collision environment related to the Lhasa-Qiangtang collision during the Late Cretaceous. Decompression induced upwelling of mantle-derived magmas to underplate and provided heat for the anatexis of thickened lower crust. Then, those Late Cretaceous magmas were brought into the southern Yidun Terrane by mixing of lower continental crust-derived melts and minor mantle-derived magmas, and the following fractional crystallization. Occurrence of these late- or post-collision magmas probably indicates that the timing of both the Lhasa-Qiangtang collision and the eastern Tibetan Plateau uplifting was earlier than the Late Cretaceous, and that the Lhasa-Qiangtang collision did not cease at least until ca. 80 Ma. Afterwards, tectonic setting of the eastern Tibetan Plateau was progressively to be under a control mainly of the subduction of the Neo-Tethys Ocean and subsequent Indo-Asian collision.

  9. Radionuclide sorption on granitic drill core material

    International Nuclear Information System (INIS)

    Distribution ratios were determined for Sr-85, Cs-134 and Eu-152 on crushed granite and fissure coating/filling material from Stripa mines. Measurements were also carried out on intact fissure surfaces. The experimental data for Sr-85, Cs-134 on crushed material can be accomodated by a sorption model based on the assumption that the crushed material consists of porous spheres with outer and inner surfaces available for sorption. In the case of Eu-152 only sorption on the outer surfaces of the crushed material was observed. The absence of sorption on inner surfaces is most probably due to high depletion of the more strongly sorbed Eu-152 in the water phase and very low diffusivity of Eu-152 in the sorbed state. (orig./HP)

  10. Prediction of uranium migration in granite media

    International Nuclear Information System (INIS)

    Choosing a preselected high level radioactive waste disposal site as study area, a hydrogeologic migration function is constructed. Several hydrogeologic parameters such as vertical dispersity, diffusion coefficient, flow velocity, simulated groundwater concentrations are discussed, and distribution coefficient of granites particles in the study area was measured by using batch method. Meanwhile the conditions after the uranium entered into the groundwater were simulated and predicted by using American hydrologic modeling software PHREEQC-II. The different roles of the various influential factors such as the pH values, dispersity and diffusion coefficient in the simulation are analyzed. The results show that pH values, dispersity and diffusion coefficient have an important influence on the nuclide migration in the groundwater of study area. (authors)

  11. Alkaline lixiviation of uranium in granitic pegmatite

    International Nuclear Information System (INIS)

    The work described herein concerns the determination of the experimental optimum conditions for the alkaline lixiviation of uranium based on the following parameters: time, pH, temperature, density and grane size. The samples were obtained from the Supamo complex, near the Currupia river in the Piar District of the Bolivar State in Venezuela. They have a granitic composition and graphitic texture. The uranium was found in them as a secondary oxidized mineral of green-yellow colour localized in fractures fissures, intergranular spaces and also in the mica as. Secondary uranitite. The lixiviation process was carried out using Na2CO3/NaHCO3 buffer solution and for 100 gr. samples the best values for an efficient process were found by using 170 mesh grane size and 500 ml of pH buffer at 700C for a 24 hour time period. (author)

  12. Expected repository environments in granite: thermal environment

    International Nuclear Information System (INIS)

    This report was prepared for the Reference Repository Conditions - Interface Working Group and will be used to formulate a standardized description of repository conditions for use by the Civilian Radioactive Waste Management Program. A baseline repository in granite is defined and three waste types are considered: unreprocessed spent fuel, commercial high-level waste, and defense high-level waste. Three different scales of repository environment are described - the very-near field (near the waste canister), the near field (the room and pillar), and the far field (the entire repository and surroundings). Information was compiled from the literature and, in addition, a number of calculations were performed. The major emphasis is on describing the thermal environment although the ground-water flow and chemical and radiation environments are also described. 61 figures, 24 tables

  13. Sorption of actinides in granitic rock

    International Nuclear Information System (INIS)

    The sorption of americium (III), neptunium(V) and plutonium on geologic media under oxic conditions has been measured by a batch technique. The aqueous phase was a synthetic groundwater or 4M NaCl solution. The solid phase was a pure mineral, representative of igneous rocks, or granite. Altogether 40 different minerals and rocks were used. The effects of pH and the ionic strength of the aqueous phase as well as of the cation exchange capacity and the surface/mass ratio of the solid sorbent are discussed. Empirical equations giving the distribution coefficient as a function of pH in the environmental pH-range 7-9 are suggested. Some observations and conclusions concerning sorption mechanisms are given. (author)

  14. Chemistry of deep groundwaters from granitic bedrock

    International Nuclear Information System (INIS)

    Water analysis data from Fjaellveden, Gideaa, Svartboberget and Kamlunge (7 different drilling holes, 26 sampling levels at vertical depths between 100 and 600 m) are discussed. Most of the waters are Na(sup)+ -Ca2(sup)+ -HCO3(sup)- -dominated with a total salt content of 200-300 mg/1 and pH of 8-9. Intrusions of Na(sup)+ -Cl(sup)- -dominated saline waters (up to 650 mg/1) are observed at great depth. The conditions are generally strongly reducing. The presence of clayish material (kaolinite, smectities) and zeolites in the fractures appears to have a large influence on the cation concentration ratios. The contents of organics, largely fulvic acids of intermediate molecular weight (180 and deuterium) indicate a non-marine origin of the water and only minor exchanges with the surroundings. The presence of tritium is evidence of intrusions of young waters in some of the samples, probably due to the disturbances during drilling and sampling. (author)

  15. Leaky cable intrusion detection sensors

    International Nuclear Information System (INIS)

    Buried Line Field Disturbance Sensors used for the purpose of outdoor perimeter intrusion detection are unique in the sense that they are covert and terrain following. Considerable effort has been spent in recent years to develop an effective Buried Line Sensor using leaky (or ported) cable technology. To date, a modular CW (Continuous Wave) approach to designing such a sensor has proven to be the most effective compromise in terms of cost, performance and installation. Proper design of a leaky cable sensor requires an in-depth knowledge of the coupling performance and attenuation characteristics of the sensor cable to be used. The ''Forward Wave'' (codirectional) method of detection is discussed. This paper contains theoretical and experimental expressions developed to demonstrate operation in terms of cost, performance and ease of installation

  16. Innovative Method for Saltwater Intrusion Control

    Directory of Open Access Journals (Sweden)

    Z. Payal

    2014-02-01

    Full Text Available Salt water intrusion is the migration of saltwater into freshwater aquifers under the influence of groundwater development (Freeze and Cherry, 1979. The most detrimental effect that ground water depletion causes lowering of water table. Another problem due to saltwater intrusion is changing saltwater freshwater interface. Methods for controlling intrusion vary widely depending on the source of the saline water, the extent of intrusion, local geology, water use and economic factors. The proposed methodology to control saltwater intrusion is (ADR Abstraction, Desalination and Recharge. The proposed methodology interplays between the major parameters of the system to control saltwater intrusion. These parameters include the soil/aquifer properties, the well locations, the well depths, the rates and the relation between the abstraction and recharge rates which depends on the recovery rate and the salinity degree. It is capable of completely preventing saltwater intrusion because it increases the volume of fresh groundwater and decreases the volume of saltwater, while considering economical aspects, environmental impact and sustainable development of water resources.

  17. Petrology and geochemistry of the proterozoic A-type granite of Kanigiri, Prakasam dist., Andhra Pradesh, India: implications for rare metal mineralisation

    International Nuclear Information System (INIS)

    The granite pluton (6.2x2.1 km2; 995±20 Ma) at Kanigiri, Prakasam district of Andhra Pradesh constitutes the southernmost part of the Prakasam alkaline complex (PAC). PAC lies to the east of the eastern margin of the Cuddapah basin, with the Dharwar schists and gneisses to its west and the eastern ghat mobile belt to its east, and is bound by two major deep faults. It comprises silica-undersaturated nepheline syenites at Elchuru, Purimetla, and Uppalapadu, saturated syenites at Settupalli, and oversaturated granitic rocks at Kanigiri and Podili. The Kanigiri granite (KG) occurs close to a major fault represented by the NW-SE flowing Mekeru river and is intrusive into the Dharwar schists, with xenoliths of the latter in the former. Petrographically, KG is a biotite granite (s.s.) with notable content of accessory minerals like fluorite and rare metal bearing minerals viz., columbite, samarskite, fergusonite, zircon, allanite, and thorite. Geochemically, it is a low Ca, metaluminous, highly fractionated alkali granite, with enrichment of Rb, Pb, Ga, Y, Zr, U, Th, Nb, and Ta, and depletion of Ba, Sr, Ti, and P. The field, petromineralogical, and geochemical aspects indicate KG as A-type (anorogenic; within plate), with (a) affinity to abortive rift-/hot spot-related continental epirogenic uplifted granitoid (CEUG) and (b) its parental melt derived by low degree partial melting of lower crustal mafic rocks at ca. 800 degC and emplaced with a near minimum melt gC and emplaced with a near minimum melt composition at about 650 deg - 700 degC at PH2O of 5 kb (assumed). This neoproterozoic A-type CEUG is fertile for rare metals and soils derived from it are potential for polymetallic (Y, REE, Nb, and Ta) minerals. (author). 27 refs., 11 figs., 3 tabs

  18. Melting of continental crust during subduction initiation: A case study from the Chaidanuo peraluminous granite in the North Qilian suture zone

    Science.gov (United States)

    Chen, Yuxiao; Song, Shuguang; Niu, Yaoling; Wei, Chunjing

    2014-05-01

    The Chaidanuo granite batholith is a ˜500 km2 homogeneous, high-level intrusion in the North Qilian oceanic suture zone. Three types of enclaves have been recognized, including (1) supracrustal xenoliths, (2) biotite gneiss that represents restite of the upper crustal melting, and (3) coeval mantle-derived mafic magmatic enclave (MME). The batholith consists dominantly of peraluminous biotite monzogranite with SiO2 69-73 wt.% and A/CNK 1.05-1.28 and shows geochemical affinity with the upper-continental crust, e.g., enrichment of large ion lithophile elements (LILEs; K, Rb, U, Th, Pb), depletion of high field strength elements (HFSEs; Nb, Ta, Ti), P, Eu, and Sr, and enriched Sr ([87Sr/86Sr]i, 0.731 to 0.744)-Nd (?Nd (t), -6.0 to -7.1) isotopes. Zircon U-Pb dating indicates that this batholith formed at 516-505 Ma, coeval with the MMEs (510 Ma), which represent the early stage of seafloor subduction in the North Qilian suture zone. The Hf isotopic composition of the MME (?Hf (t) = -6.0 to +2.1) is more depleted than that of the host granite (?Hf (t) = -14.8 to -4.7), suggesting mixing of mantle- and crust-derived melts. The inherited zircon cores in the host granite yield an age peak at ˜750 Ma with a few detritals of 591-1683 Ma. Zircons from a biotite gneiss enclave yield a protolith age of 744 Ma and a metamorphic/melting event at 503 Ma. Sr-Nd isotopic modeling reveals that the batholith was generated by melting of Neoproterozoic granitic rocks with the addition of 10-18% mantle-derived magma. Therefore, peraluminous granite can be produced by melting of crustal materials heated by mantle-derived magmas during the early stage of subduction initiation at the site of a prior passive continental margin.

  19. High heat production (HHP) granites, hydrothermal circulation and ore genesis

    International Nuclear Information System (INIS)

    The final paper given at the conference on high heat production granites held in St. Austell, Cornwall in September, 1985, is a commentary on the presentations and concluding discussion. Half the papers were directed to the present state of knowledge on HHP granites and mineralization. Others were concerned with the distribution of uranium and thorium in St. Austell granite and tin-tungsten mineralization. The importance of the study of the decay of radioelements in understanding the whole spectrum of geologic processes was emphasised. (UK)

  20. The source rock characters of U-rich granite

    International Nuclear Information System (INIS)

    This paper discusses the stratum composition, lithological association, uranium content of crust and the activation, migration, concentration of uranium at each tectonic cycle in South China. The authors point out that the source rock of U-rich granite is U-rich continental crust which is rich in Si, Al and K. The lithological association is mainly composed of terrestrial clastic rocks formation of mudstone and sandstone, mingled with intermediate-acidic, mafic pyroclastic rocks and carbonate rocks formation. During tectonic movements, the rocks had undergone regional metamorphism, migmatitization, granitization, and formed U-rich granites finally. (authors)

  1. Vertical zonality of fractionated granite plutons reflected in zircon chemistry.

    Czech Academy of Sciences Publication Activity Database

    Breiter, Karel

    s. l : Universidad d Salamanca ; Escuela politécnica superior de Avila ; Universidad de Granada, 2011 - (Molina, J.; Scarrow, J.; Bea, F.; Montero, P.). s. 25-25 ISBN 978-84-694-5253-0. [Hutton Symposium on Granites and Related Rocks /7./. 04.07.2011-09.07.2011, Avila] Institutional research plan: CEZ:AV0Z30130516 Keywords : zircon * granite geochemistry * granite zonality * Cínovec * Beauvoir Subject RIV: DB - Geology ; Mineralogy http://www.seventh-hutton.org/meeting/Abstracts,_posters,_Lithos_Special_Issue_files/abstracts_book_Hutton_ISBN.pdf

  2. Sorption behavior of Am(III) onto granite

    International Nuclear Information System (INIS)

    Sorption behavior of Am(III) onto granite was investigated. The distribution coefficient (Kd) of Am(III) onto granite was determined in the solution pH of which was ranged from 2.9 to 11.4 and ionic strength was set at 10-2 and 10-1. The Kd values were found to increase with increasing pH and with decreasing ionic strength. The obtained data were successfully analyzed by applying an electrical double layer model. The optimum parameters of the double layer electrostatics and adsorption reactions were obtained, and the selective adsorption behavior of Am(III) onto the granite was discussed. (author)

  3. Intrusion detection using deep belief network

    International Nuclear Information System (INIS)

    This paper proposes an intrusion detection technique based on DBN (Deep Belief Network) to classify four intrusion classes and one normal class using KDD-99 dataset. The proposed technique is based on two phases: in first phase it removes the class imbalance problem and in the next, it applies DBN followed by FFNN (Feed-Forward Neural Network) to build a prediction model. The obtained results are compared with those given in (9). The prediction accuracy of our model shows promising results on both intrusion and normal patterns. (author)

  4. 2005 dossier: granite. Tome: phenomenological evolution of the geologic disposal; Dossier 2005: Granite. Tome evolution phenomenologique du stockage geologique

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    This document makes a status of the researches carried out by the French national agency of radioactive wastes (ANDRA) about the phenomenological aspects of the geologic disposal of high-level and long-lived radioactive wastes (HLLL) in granite formations. Content: 1 - introduction: ANDRA's research program on disposal in granitic formation; 2 - the granitic environment: geologic history, French granites; 3 - HLLL wastes and disposal design concepts; 4 - identification, characterization and modeling of a granitic site: approach, geologic modeling, hydrologic and hydro-geochemical modeling, geomechanical and thermal modeling, long-term geologic evolution of a site; 5 - phenomenological evolution of a disposal: main aspects of the evolution of a repository with time, disposal infrastructures, B-type wastes disposal area, C-type wastes disposal area; spent fuels disposal area, radionuclides transfer and retention in the granitic environment; 6 - conclusions: available knowledge, methods and tools for the understanding and modeling of the phenomenological evolution of a granitic disposal site. (J.S.)

  5. Mantle-Type Granites From Jilotlan, Jalisco, Mexico: Geochemical and Isotopic Evidence

    Science.gov (United States)

    Solis-Pichardo, G.; Schaaf, P.; Hernandez, T.; Salazar, J.; Villanueva, D.

    2008-12-01

    The Jilotlan Intrusive, located in the State of Jalisco, SW Mexico, almost 100 km off the Pacific coast and the actual Middle American trench, occupies a semicircular area of nearly 6,000 km2. The composite plutonic body consists of several phases: from gabbros and diorites to tonalites, granodiorites and granites. Locally, the granitic member intrudes the gabbro. The area is extensively intruded by several dike generations of mafic composition, although minor acidic dikes are observed as well. The Jilotlan pluton intrudes mid- Cretaceous volcanosedimentaries and carbonates. Representative units of the gabbroic members were sampled for petrographic studies, major, trace geochemical data and Rb-Sr and Sm-Nd isotopic investigations. Textural variations of gabbroic rocks in the field are ubiquitous. Main mineral phases consist of plagioclase with amphiboles and clinopyroxene. Chemically, products are quite heterogeneous too, displayed by a light spread of SiO2, MgO, Na2O and K2O (46.6-52.4, 4.0-9.9, 1.8-4.1, and 0.3-2.7 wt.%., respectively) at a magmatically primitive level. Total alkalis vary from 2.5 to 5.2 characterizing the rocks as belonging to the calc-alkaline suite. Multielemental diagrams show similar patterns with Cs, Rb and Ba enrichment and positive anomalies of Pb and Sr. REE diagrams exhibit a relatively flat pattern together with a light LREE enrichment. Initial isotopic signatures (at 70 Ma, Rb-Sr, WR) of gabbros are very low, with 87Sr/86Sr between 0.70328 and 0.70369 and similar epsilon-Nd values from +4.7 to +6.8. Tonalites and granodiorites have slightly higher, less dispersed 87Sr/86Sr ratios and epsilon-Nd values (0.70369-0.70379, and +2.6 to +3.7 respectively). Isotopic signatures of gabbros are similar to rocks from the close by Manzanillo batholith. Both gabbros from Jilotlan and Manzanillo form one of the largest gabbro provinces known in Mexico, with Sr-Nd isotopic ratios even more primitive than most of Trans Mexican Volcanic Belt volcanics. These results indicate a mantle origin of these continental arc intrusives, associated to Cordilleran subduction processes, which constitutes a rare scenario in magmatic arcs. There is no evidence for accretion or for significant crustal assimilation.

  6. The Phalaborwa Syenite Intrusions along the West-Central Boundary of the Kruger National Park

    Directory of Open Access Journals (Sweden)

    C. Frick

    1986-12-01

    Full Text Available The geology of the Phalaborwa Complex is described and emphasis placed on the distribution of the large number of syenite intrusions. The petrography of the different textural types of syenites is discussed and it is shown that porphyritic, granular, gneissic and hypidiomorphic syenites are present. The petrography shows that the deformation textures, which are present in some of the syenites, may have formed during the emplacement of syenitic magmas which contained a high concentration of crystals. The geochemistry of the syenites is discussed and it is shown that they were not derived from an alkali basaltic magma through fractional crystallisation, but that they may rather represent alkali basaltic magmas which were contaminated by granitic material. The mode of emplacement of the Phalaborwa Complex is discussed and the relationship between the pyroxenites is explained.

  7. Thermo-chronological study of hydrothermal systems and magma intrusion. ; Example from Goto-Fukue island, Nagasaki, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, K. (Kyushu University, Fukuoka (Japan))

    1992-08-31

    The geothermal history of altered granite porphyry in the Goto-Fukue Island was studied by fission track length analysis and K-Ar dating of hydrothermal minerals. The sample A not hydrothermally altered, the sample B greatly altered to form chlorite and the altered rock sample C composed of sericite were collected, and zircon separated from them were used for the fission track length analysis. The same samples were also dated by conventional K-Ar method. As a result, the date of 11.3 Ma for the sample A showed the timing of cooling down to 200[degree]C in the western part of the island after magma intrusion at nearly 15 Ma. The date of 6.6 Ma for the sample B suggested the reset by subsequent thermal events. The date of 14.5 Ma for sericite from the sample C indicated that sericite minerals were formed at nearly the same time as high temperature alteration. Therefore, in the eastern part of the island, although high level alteration occurred just after intrusion of granite porphyry, no subsequent thermal events could be detected. 1 ref., 3 figs.

  8. Late Neoproterozoic post-collisional mafic magmatism in the Arabian-Nubian Shield: A case study from Wadi El-Mahash gabbroic intrusion in southeast Sinai, Egypt

    Science.gov (United States)

    Khalil, A. E. S.; Obeid, M. A.; Azer, M. K.

    2015-05-01

    Late Neoproterozoic gabbroic intrusion of Wadi El-Mahash lays in the northwestern sector of the Arabian-Nubian Shield (ANS) which is exposed in the Sinai Peninsula, Egypt. It occurs as small undeformed mafic body intruding metamorphic rocks and truncated by alkali granites. Field relations, mineralogical characteristics and chemical data indicate that Wadi El-Mahash mafic intrusion is unmetamorphosed. The intrusion consists of medium- to coarse-grained gabbroic rocks. The medium-grained one (hornblende gabbro) formed nearly simultaneous with, or slightly later than, the coarse-grained rock (pyroxene-hornblende gabbro). Geochemically, the gabbroic samples are characterized by enrichment in LILE relative to HFSE and LREE relative to HREE [(La/Yb)n = 4.52-6.35]. They show geochemical signature similar to other post-collisional gabbroic intrusions of south Sinai. The subduction-related geochemical characteristic of the gabbroic intrusion of Wadi El-Mahash can be explained by partial melting of a relatively enriched lithospheric mantle source following a previous subduction process in the ANS. The gabbroic rocks crystallized at pressures between 6.2 and 6.5 kbar (?15-20 km depth) with crystallization temperature ranging from 750 to 970 °C. Lithospheric delamination model is suggested for the mafic magma of Wadi El-Mahash since delamination of lithospheric mantle allowed asthenosphere to rise rapidly causing partial melting and generating gabbroic melts. The produced melts then infiltrated the base of the crust to induce the post-collisional magmatism in south Sinai.

  9. Acceptance of Smart Phone by Younger Consumers in Malaysia

    Directory of Open Access Journals (Sweden)

    Yong Hoe Hong

    2014-02-01

    Full Text Available The sales of smart phone are rapidly increasing in Malaysia and in the global markets. Which means that, smart phone has a great opportunity in the future growth of the mobile industry. The aim of this research is to determine the acceptance of smart phone by younger consumers in Malaysia. A total of 113 useable questionnaires was collected and analyzed through SPSS. Google doc form was utilized to create the online questionnaire. The data collection method utilized in this paper was online interview. The result shows that, perceived usefulness (PU, perceived ease of use (PEOU, and Internet self-efficacy (ISE significantly influenced the acceptance of smart phone by younger consumers in Malaysia. However, no relationship exists among Internet self-efficacy, perceived usefulness and perceived ease of use. Future studies should explore more on other factors to determine the acceptance of smart phone.

  10. Hippocampal sclerosis in children younger than 2 years

    Energy Technology Data Exchange (ETDEWEB)

    Kadom, Nadja [Children' s National Medical Center, Department of Diagnostic Imaging and Radiology, Washington, DC (United States); Tsuchida, Tammy; Gaillard, William D. [Children' s National Medical Center, Department of Neurology, Washington, DC (United States)

    2011-10-15

    Hippocampal sclerosis (HS) is rarely considered as a diagnosis in children younger than 2 years. To describe imaging features in conjunction with clinical information in patients with hippocampal sclerosis who are younger than 2 years. We retrospectively reviewed MR brain imaging and clinical information in five children in whom the diagnosis of HS was made both clinically and by MRI prior to 2 years of age. Imaging features establishing the diagnosis of hippocampal sclerosis were bright T2 signal and volume loss, while the internal architecture of the hippocampal formation was preserved in almost all children. Clinically, all children had an infectious trigger. It is necessary for radiologists to consider HS in children with certain clinical features to plan an MRI protocol that is appropriate for detection of hippocampal pathology. (orig.)

  11. Prevention and analysis of hacker's intrusion

    International Nuclear Information System (INIS)

    The author analyzes the behavior characteristics and relevant technologies about the hacker's intrusion, and gives some corresponding solutions pertinently. To the recent events about hackers, the author gives detailed introduction and puts forward the relevant advice and valuable consideration

  12. Autonomous Rule Creation for Intrusion Detection

    Energy Technology Data Exchange (ETDEWEB)

    Todd Vollmer; Jim Alves-Foss; Milos Manic

    2011-04-01

    Many computational intelligence techniques for anomaly based network intrusion detection can be found in literature. Translating a newly discovered intrusion recognition criteria into a distributable rule can be a human intensive effort. This paper explores a multi-modal genetic algorithm solution for autonomous rule creation. This algorithm focuses on the process of creating rules once an intrusion has been identified, rather than the evolution of rules to provide a solution for intrusion detection. The algorithm was demonstrated on anomalous ICMP network packets (input) and Snort rules (output of the algorithm). Output rules were sorted according to a fitness value and any duplicates were removed. The experimental results on ten test cases demonstrated a 100 percent rule alert rate. Out of 33,804 test packets 3 produced false positives. Each test case produced a minimum of three rule variations that could be used as candidates for a production system.

  13. STATISTICAL TECHNIQUES IN ANOMALY INTRUSION DETECTION SYSTEM

    Directory of Open Access Journals (Sweden)

    Hari Om

    2012-11-01

    Full Text Available In this paper, we analyze an anomaly based intrusion detection system (IDS for outlier detection in hardware profile using statistical techniques: Chi-square distribution, Gaussian mixture distribution and Principal component analysis. Anomaly detection based methods can detect new intrusions but they suffer from false alarms. Host based Intrusion Detection Systems (HIDSs use anomaly detection to identify malicious attacks i.e. intrusion. The features are shown by large set of dimensions and the system becomes extremely slow during processing this huge amount of data (especially, host based. We show the comparative results using three different approaches: Principal Component Analysis (PCA, Chi-square distribution and cluster with Gaussian mixture distribution. We get good results using these techniques.

  14. Multilayer Intrusion Detection System In Web Application Based Services

    OpenAIRE

    Narmadha.S; Deepak Lakshmi Narashima

    2013-01-01

    Web based services having a data transfer from different layer. Web services separate layer for the data transfer and the process is difficult in the service. Service transferring data is having intrusion from the user interaction in web based services to detect the intrusion in alert basis and detect the intrusion in both online and offline. In offline alert data previously having attack basis it can be rectified. The online alert system data having the intrusion collect the intrusion in buf...

  15. Java-Based Intrusion Detection System in a Wired Network

    OpenAIRE

    Ezin, Euge?ne C.; Hervé Akakpo Djihountry

    2011-01-01

    Intrusion Detection has become an integral part of the information security process. The cost involved in protecting network resources is often neglected when compared with the actual cost of a successful intrusion, which strengthens the need to develop more powerful intrusion detection systems. Many existing systems for intrusion detection are developed in C, Objective-C, Tcl, C++ programming languages. In this paper, we design and develop a network intrusion detection system using Java prog...

  16. Selective adsorption behavior of cesium ions onto granite

    International Nuclear Information System (INIS)

    The adsorption behavior of Cs+ onto granite was investigated. The distribution coefficient (Kd) of Cs+ onto granite was determined in the solution of which pH was ranged from 2.3 to 10.9 and ionic strength was set at 10-2 and 10-1. It is found that the Kd values for granite were larger than those for quartz, and the Kd values were found to increase with increasing pH and with decreasing ionic strength. The obtained data were successfully analyzed by an electrical double layer model and the optimum parameter values of the double layer electrostatics and adsorption reactions were obtained. The selective adsorption behavior of Cs+ onto the mineral components was discussed, and Cs+ were considered to be mainly adsorbed onto feldspars in the granite. (author)

  17. Younger Dryas deglaciation of Scotland driven by warming summers

    OpenAIRE

    Bromley, Gordon R. M.; Putnam, Aaron E.; Rademaker, Kurt M.; Lowell, Thomas V.; Schaefer, Joerg M.; Hall, Brenda; Winckler, Gisela; Birkel, Sean D.; Borns, Harold W.

    2014-01-01

    Resolving the full manifestation of past abrupt climate change is key to understanding the processes driving and propagating these events. As a principal component of global heat transport, the North Atlantic Ocean also is susceptible to rapid disruptions of meridional overturning circulation and thus widely invoked as a cause of abrupt climate variability in the Northern Hemisphere. We assess the impact of one such North Atlantic cold event—the Younger Dryas Stadial—on an adjacent ice ma...

  18. Total hip arthroplasty in patients 50 years and younger.

    Science.gov (United States)

    McAuley, James P; Szuszczewicz, Edward S; Young, Anthony; Engh, Charles A

    2004-01-01

    Because the young patient with a total hip arthroplasty is presumed to place increased demands on a reconstruction for a longer period than the average patient with a hip replacement, long-term results are expected to be inferior. To determine the efficacy of total hip replacements in this population, the current authors reviewed the long-term results of patients who were 50 years and younger who had cementless total hip arthroplasties at their institution, and reviewed the literature on total hip arthroplasty in younger patients. The results from the study population and the literature were encouraging. At the author's institute, during the past 20 years, 561 hip replacements were done on 488 patients in this age group, using extensively porous-coated cobalt-chromium stems matched with beaded, press-fit acetabular components of cobalt-chrome or titanium. Using the Kaplan-Meier technique, the survival rates for femoral and acetabular components, using any revision as an end point, were 89% at 10-year followup and 60% at 15-year followup. A subset of the authors' patients who were 40 years and younger (256 hips, 223 patients) had slightly inferior results, with 85% 10-year survivorship and 54% 15-year survivorship, using any revision as an end point. A comprehensive literature review also showed that long-term success can be achieved with cemented or cementless total hip arthroplasties in young patients. Because some reconstructions exhibited inferior results in younger patients, the authors recommend that surgeons be much more critical of the components used in these patients and allow long-term data to guide their decisions. PMID:15043102

  19. Younger adults with severe physical disabilities in the Capital Region

    OpenAIRE

    Gutman, Gloria M.; Anderson, K.; Killam, J.

    1995-01-01

    In Spring, 1994 the Gerontology Research Centre at Simon Fraser University was commissioned to undertake a project that would provide the Health Planning Division of the Capital Regional District of British Columbia (CRD) with information that would facilitate strategic planning for younger adults with severe physical disabilities. The specific goals of the project were to: 1) define the pertinent characteristics of persons aged 19-55 with severe physical disabilities living in the CRD, inclu...

  20. Emotional facial processing in younger and older adults

    OpenAIRE

    Sva?rd, Joakim

    2015-01-01

    There is evidence that older adults have difficulty processing negative but not positive facial expressions. This positivity effect among older adults is expressed in attention to as well as in memory and recognition of emotional faces. In the present thesis, effects of stimulus properties (i.e., self ratings of valence, arousal, potency), context, and visual exploration were investigated. In Study I, the aim was to investigate a happy face advantage seen in younger adult...

  1. Habitual fat intake predicts memory function in younger women

    OpenAIRE

    Edward LeighGibson; SuzanneBarr

    2013-01-01

    High intakes of fat have been linked to greater cognitive decline in old age, but such associations may already occur in younger adults. We tested memory and learning in 38 women (25 to 45 years old), recruited for a larger observational study in women with polycystic ovary syndrome. These women varied in health status, though not significantly between cases (n = 23) and controls (n = 15). Performance on tests sensitive to medial temporal lobe function (CANTABeclipse, Cambridge Cognition Ltd,...

  2. Acceptance of Smart Phone by Younger Consumers in Malaysia

    OpenAIRE

    Yong Hoe Hong; Boon Heng Teh; Chin Hooi Soh

    2014-01-01

    The sales of smart phone are rapidly increasing in Malaysia and in the global markets. Which means that, smart phone has a great opportunity in the future growth of the mobile industry. The aim of this research is to determine the acceptance of smart phone by younger consumers in Malaysia. A total of 113 useable questionnaires was collected and analyzed through SPSS. Google doc form was utilized to create the online questionnaire. The data collection method utilized in this paper was online i...

  3. Unsupervised Genetic Algorithm Deployed for Intrusion Detection

    OpenAIRE

    Bankovic, Zorana; Bojanic, Slobodan; Nieto-taladriz Garci?a, Octavio; Badii, Atta

    2008-01-01

    This paper represents the first step in an on-going work for designing an unsupervised method based on genetic algorithm for intrusion detection. Its main role in a broader system is to notify of an unusual traffic and in that way provide the possibility of detecting unknown attacks. Most of the machinelearning techniques deployed for intrusion detection are supervised as these techniques are generally more accurate, but this implies the need of labeling the data for training and testing whic...

  4. Adaptive Genetic Algorithm Model for Intrusion Detection

    OpenAIRE

    Anil Kumar, K. S.; Nanda Mohan, Dr V.

    2012-01-01

    Intrusion detection systems are intelligent systems designed to identify and prevent the misuse of computer networks and systems. Various approaches to Intrusion Detection are currently being used, but they are relatively ineffective. Thus the emerging network security systems need be part of the life system and this ispossible only by embedding knowledge into the network. The Adaptive Genetic Algorithm Model - IDS comprising of K-Means clustering Algorithm, Genetic Algorithm and Neural Netwo...

  5. Perceived illness intrusion among patients on hemodialysis

    OpenAIRE

    Bapat Usha; Kedlaya Prashanth; Gokulnath,

    2009-01-01

    Dialysis therapy is extremely stressful as it interferes with all spheres of daily acti-vities of the patients. This study is aimed at understanding the perceived illness intrusion among pa-tients on hemodialysis (HD) and to find the association between illness intrusion and patient demo-graphics as well as duration of dialysis. A cross sectional study involving 90 patients with chronic kidney disease (CKD) stage V, on HD was performed during the period from 2005 to 2006. The subjects include...

  6. Using Commodity Coprocessors for Host Intrusion Detection

    OpenAIRE

    Seger, Mark M.

    2012-01-01

    The ever-rising importance of communication services and devices emphasizes the significance of intrusion detection. Besides general network attacks, private hosts in particular are within the focus of cyber criminals. Private data theft and the integration of individual hosts into large-scale botnets are two common purposes successfully subverted systems are used for. In order to detect any attack, intrusion detection mechanisms need to probe the data in question. Therefore, the acquisition ...

  7. Intrusion Detection System Using Advanced Honeypots

    OpenAIRE

    Singh, Ram Kumar; Ramajujam, Prof T.

    2009-01-01

    The exponential growth of Internet traffic has made public servers increasingly vulnerable to unauthorized accesses and intrusions. In addition to maintaining low latency for the client, filtering unauthorized accesses has become one of the major concerns of a server maintainer. This implementation of an Intrusion Detection System distinguishes between the traffic coming from clients and the traffic originated from the attackers, in an attempt to simultaneously mitigate the ...

  8. An Architecture of Hybrid Intrusion Detection System

    OpenAIRE

    Patel, Kanubhai K.; Buddhadev, Bharat V.

    2012-01-01

    Intrusion Detection System (IDS) is renowned and widely-deployed security tool to detect attacks and malicious activities in information system. It is an essential element of any contemporary information system. There are mainly two techniques for intrusion detection: i) signature-based (misuse) detection and ii) anomaly-based detection technique. Both the techniques have their advantages and disadvantages. This paper presents research from an ongoing study on the use of features of both the ...

  9. Improving Intrusion Detection Using Genetic Algorithm

    OpenAIRE

    Muda, Z.; Moraveji Hashemi, V.; Yassin, W.

    2013-01-01

    Intrusion Detection System (IDS) is one of the key security components in today’s networking environment. A great deal of attention has been recently paid to anomaly detection to accomplish intrusion detection. However, a major problem with this approach is maximizing detection rate and accuracy, as well as minimizing false alarm i.e., inability to correctly discover particular types of attacks. To overcome this problem, a genetic algorithm approach is proposed. Genetic Algorithm (GA) is mo...

  10. Data Reduction in Intrusion Alert Correlation

    OpenAIRE

    Tedesco, Gianni; Aickelin, Uwe

    2006-01-01

    Network intrusion detection sensors are usually built around low level models of network traffic. This means that their output is of a similarly low level and as a consequence, is difficult to analyze. Intrusion alert correlation is the task of automating some of this analysis by grouping related alerts together. Attack graphs provide an intuitive model for such analysis. Unfortunately alert flooding attacks can still cause a loss of service on sensors, and when performing a...

  11. Intrusion problematic during water supply systems' operation

    OpenAIRE

    Mora Rodríguez, José de Jesús; López Jiménez, Petra Amparo; Ramos, Helena M.

    2011-01-01

    Intrusion through leaks occurrence is a phenomenon when external fluid comes into water pipe systems. This phenomenon can cause contamination problems in drinking pipe systems. Hence, this paper focuses on the entry of external fluids across small leaks during normal operation conditions. This situation is especially important in elevated points of the pipe profile. Pressure variations can origin water volume losses and intrusion of contaminants into the drinking water pipes. ...

  12. Intrusion problematic during water supply systems’ operation

    OpenAIRE

    Jesus Mora-Rodriguez, P. Amparo López-Jimenez, Helena M. Ramos

    2011-01-01

    Intrusion through leaks occurrence is a phenomenon when external fluid comes into water pipe systems. This phenomenon can cause contamination problems in drinking pipe systems. Hence, this paper focuses on the entry of external fluids across small leaks during normal operation conditions. This situation is especially important in elevated points of the pipe profile. Pressure variations can origin water volume losses and intrusion of contaminants into the drinking water pipes. This work focuse...

  13. Paleo-redox boundaries in fractured granite

    DEFF Research Database (Denmark)

    Dideriksen, K.; Christiansen, B. C.

    2010-01-01

    At the Earth's surface, Fe(II) often oxidises and forms insoluble Fe(III)-(oxyhydr)oxides, whose particle size and structure depend on solution composition and temperature during formation and afterwards. Bacterial processes and exposure to reducing environments reduces them again, releasing dissolved iron to the groundwater. During such cycling, the Fe isotopes fractionate to an extent that is expected to depend on temperature. In this study, we report on the use of Fe-oxides as paleoredox indicators, using their structure, morphology and Fe-composition as a clue for formation conditions. In samples taken from similar to 120 m drill cores in granite from SE Sweden, X-ray amorphous, superparamagnetic, nanometre-sized Fe-oxides are confined to fractures of the upper,-,50 m, whereas well-crystalline Fe-oxides, with particle sizes typical for soils, occur down to similar to 110 m. We also identified hematite with a particle size of 100 nm, similar to hematite of hydrothermal origin. The Fe isotope composition ofthe fine-grained Fe-oxides (-1 parts per thousand granite. The absence of natural, low-temperature Fe-oxides from deeper drill cores suggests that oxygenated waters do not readily penetrate beyond about 100 m and suggests that radioactive waste repositories located at a depth of similar to 500 m should be well-protected from oxygenated waters.

  14. Evaluation of radon exhalation rate from granite stone

    International Nuclear Information System (INIS)

    This study evaluates radon exhalation rate from 10 different granite stones, used for building construction in Iran. Radon exhalation rate ranged from non-detectable to 0.6 Bq m-2h-1. Six samples had exhalation rate above detectable level. A significant statistical relationship between radon exhalation rate with 226Ra and 232Th indicated that 226Ra and 232Th were responsible for radon exhalation from granite stones. (author)

  15. Radionuclide Transport in Fracture-Granite Interface Zones

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Q; Mori, A

    2007-09-12

    In situ radionuclide migration experiments, followed by excavation and sample characterization, were conducted in a water-conducting shear zone at the Grimsel Test Site (GTS) in Switzerland to study diffusion paths of radionuclides in fractured granite. In this work, we employed a micro-scale mapping technique that interfaces laser ablation sampling with inductively coupled plasma-mass spectrometry (LA/ICP-MS) to measure the fine-scale (micron-range) distribution of actinides ({sup 234}U, {sup 235}U, and {sup 237}Np) in the fracture-granite interface zones. Long-lived {sup 234}U, {sup 235}U, and {sup 237}Np were detected in flow channels, as well as in the adjacent rock matrix, using the sensitive, feature-based mapping of the LA/ICP-MS technique. The injected sorbing actinides are mainly located within the advective flowing fractures and the immediately adjacent regions. The water-conducting fracture studied in this work is bounded on one side by mylonite and the other by granitic matrix regions. These actinides did not penetrate into the mylonite side as much as the relatively higher-porosity granite matrix, most likely due to the low porosity, hydraulic conductivity, and diffusivity of the fracture wall (a thickness of about 0.4 mm separates the mylonite region from the fracture) and the mylonite region itself. Overall, the maximum penetration depth detected with this technique for the more diffusive {sup 237}Np over the field experimental time scale of about 60 days was about 10 mm in the granitic matrix, illustrating the importance of matrix diffusion in retarding radionuclide transport from the advective fractures. Laboratory tests and numerical modeling of radionuclide diffusion into granitic matrix was conducted to complement and help interpret the field results. Measured apparent diffusivity of multiple tracers in granite provided consistent predictions for radionuclide transport in the fractured granitic rock.

  16. Radionuclide Transport in Fracture-Granite Interface Zones

    International Nuclear Information System (INIS)

    In situ radionuclide migration experiments, followed by excavation and sample characterization, were conducted in a water-conducting shear zone at the Grimsel Test Site (GTS) in Switzerland to study diffusion paths of radionuclides in fractured granite. In this work, we employed a micro-scale mapping technique that interfaces laser ablation sampling with inductively coupled plasma-mass spectrometry (LA/ICP-MS) to measure the fine-scale (micron-range) distribution of actinides (234U, 235U, and 237Np) in the fracture-granite interface zones. Long-lived 234U, 235U, and 237Np were detected in flow channels, as well as in the adjacent rock matrix, using the sensitive, feature-based mapping of the LA/ICP-MS technique. The injected sorbing actinides are mainly located within the advective flowing fractures and the immediately adjacent regions. The water-conducting fracture studied in this work is bounded on one side by mylonite and the other by granitic matrix regions. These actinides did not penetrate into the mylonite side as much as the relatively higher-porosity granite matrix, most likely due to the low porosity, hydraulic conductivity, and diffusivity of the fracture wall (a thickness of about 0.4 mm separates the mylonite region from the fracture) and the mylonite region itself. Overall, the maximum penetration depth detected with this technique for the more diffusive 237Np over the field expfusive 237Np over the field experimental time scale of about 60 days was about 10 mm in the granitic matrix, illustrating the importance of matrix diffusion in retarding radionuclide transport from the advective fractures. Laboratory tests and numerical modeling of radionuclide diffusion into granitic matrix was conducted to complement and help interpret the field results. Measured apparent diffusivity of multiple tracers in granite provided consistent predictions for radionuclide transport in the fractured granitic rock.

  17. Infiltration Characteristics of Granitic Residual Soil of Various Weathering Grades

    Directory of Open Access Journals (Sweden)

    Faisal H. Ali

    2005-01-01

    Full Text Available This study presents the result of a field study on the infiltration characteristics of cut a slope in granitic residual soil of various weathering grades. Granitic residual soil of weathering grade IV is found to have the highest infiltration rate. Water infiltration is found to increase from grade VI to IV and decrease from grade IV to grade III. Water infiltration is found to increase with the increase in soil porosity and void ratio.

  18. Network Intrusion Detection using Support Vector Regression

    Directory of Open Access Journals (Sweden)

    Govindarajan Muthukumarasamy

    2011-04-01

    Full Text Available Data Mining is the use of algorithms to extract the information and patterns derived by the knowledge discovery in databases process. Classification maps data into predefined groups or classes. It is often referred to as supervised learning because the classes are determined before examining the data. This paper addresses using ensemble approach of Support Vector Regression for intrusion detection. Due to increasing incidents of cyber attacks, building effective intrusion detection systems (IDS are essential for protecting information systems security, and yet it remains an elusive goal and a great challenge. The feasibility and the benefits of the proposed approach are demonstrated by means of data mining problem: Network Intrusion Detection. Intrusion detection systems help network administrators prepare for and deal with network security attacks. These systems collect information from a variety of systems and network sources, and analyze them for signs of intrusion and misuse.  We show that proposed ensemble of Support Vector Regression is superior to individual approach for intrusion detection in terms of classification rate.

  19. Earth's youngest exposed granite and its tectonic implications: the 10–0.8 Ma Kurobegawa Granite

    OpenAIRE

    Hisatoshi Ito; Ryuji Yamada; Akihiro Tamura; Shoji Arai; Kenji Horie; Tomokazu Hokada

    2013-01-01

    Although the quest for Earth's oldest rock is of great importance, identifying the youngest exposed pluton on Earth is also of interest. A pluton is a body of intrusive igneous rock that crystallized from slowly cooling magma at depths of several kilometers beneath the surface of the Earth. Therefore, the youngest exposed pluton represents the most recent tectonic uplift and highest exhumation. The youngest exposed pluton reported to date is the Takidani Granodiorite (~ 1.4 Ma) in the Hida Mo...

  20. The mineralogy and geochemistry of quartz-tourmaline schlieren in the granites of the Primorsky Complex, Western Baikal Region

    Science.gov (United States)

    Savel'eva, V. B.; Bazarova, E. P.; Kanakin, S. V.

    2014-12-01

    Quartz-tourmaline schlieren have been found within rapakivi-like granites of the Early Proterozoic Primorsky Complex in the Western Baikal Region. These rocks are biotite leucogranites with normal alkalinity (A/CNK = 1.00-1.04); a high iron mole fraction (92-95%); a K2O/Na2O value of about 2.0; relatively high F, Li, Rb, Cs, Sn, Pb, Th, and U contents; and low Ba, Sr, Eu, Zn, Sc, and V contents. The schlieren composed of quartz and tourmaline with relics of feldspar also contain fluorite, rare muscovite, chlorite, and accessory rutile, ilmenite, zircon, monazite, xenotime, and bastnäsite. B2O3 and F contents in the schlieren are 2.29-2.63 and 0.30-0.47 wt %, respectively. Fe2O3 (4.8-5.4 wt %), F, and H2O contents are higher in these schlieren than in the host granite, while SiO2, CaO, Na2O, K2O, and P2O5 contents are lower than in host rocks. K2O/Na2O values decrease in the schlieren down to 0.4. Enrichment of the schlieren in Fe and other ore elements (Zn, Co, Cu, Sn, etc.), together with B, F, H2O, and Na, suggests that they crystallized from fluid-saturated melt segregated from aluminosilicate melt in the apical part of a shallow-seated intrusion. The formation of tourmaline may be related to the interaction of the fluid with feldspars in the crystallizing granites; it was accompanied by a separation of fluid F-CO2. Quartz precipitated at the next stage, due to the acidic character of the aqueous fluid. In general, the relationships of minerals in the schlieren indicate distinct fractionation of LREE, HREE, and Y in the fluid-saturated melt.

  1. Alpha intrusion on ovenight polysomnogram

    Directory of Open Access Journals (Sweden)

    Nahapetian R

    2014-06-01

    Full Text Available No abstract available. Article truncated after 150 words. A 30 year-old Army veteran with a past medical history significant for chronic lumbar back pain stemming from a fall-from-height injury sustained in 2006 was referred to the sleep laboratory for evaluation of chronic fatigue and excessive daytime hypersomnolence. His Epworth sleepiness scale score was 16. He denied a history of snoring and witnessed apnea. Body Mass Index (BMI was 25.7 kg/m2. His main sleep related complaints were frequent nocturnal arousals, poor sleep quality, un-refreshing sleep, prolonged latency to sleep onset, and nightmares. An In-lab attended diagnostic polysomnogram was performed. Sleep efficiency was reduced (73% and overall arousal index was not significantly elevated (3.2 events/hour. The sleep study showed rapid eye movement (REM related sleep disordered breathing that did not meet diagnostic criteria for sleep apnea. There was no evidence for period limb movement disorder. However, the study was significant for alpha wave intrusion in stage N2 non-REM and stage ...

  2. Occurrence of seawater intrusion overshoot

    Science.gov (United States)

    Morgan, Leanne K.; Bakker, Mark; Werner, Adrian D.

    2015-04-01

    A number of numerical modeling studies of transient sea level rise (SLR) and seawater intrusion (SI) in flux-controlled aquifer systems have reported an overshoot phenomenon, whereby the freshwater-saltwater interface temporarily extends further inland than the eventual steady state position. Recently, physical sand-tank modeling has shown overshoot to be a physical process. In this paper, we have carried out numerical modeling of SLR-SI to demonstrate that overshoot can occur at the field scale within unconfined aquifers. This result is contrary to previous conclusions drawn from a restricted number of cases. In addition, we show that SI overshoot is plausible under scenarios of gradual sea level rise that are consistent with conditions predicted by the Intergovernmental Panel for Climate Change. Overshoot was found to be largest in flux-controlled unconfined aquifers characterized by low freshwater flux, high specific yield, and large inland extent. These conditions result in longer timeframes for the aquifer to reach new steady state conditions following SLR, and the extended period prior to reequilibration of the groundwater flow field produces more extensive overshoot.

  3. Pilot heater test in the Stripa granite

    International Nuclear Information System (INIS)

    In the Stripa mine, situated in the central part of Sweden, a pilot heater test has been carried out at 348-m level. The type of rock is a granite with a rather high frequency of fractures. A central main heater with a length of 3 m, a diameter of 30 cm and a total power of 6 kW was placed at the bottom of a 10-m-deep borehole. At different radial distances, varying from 0.85 m up to 2.95 m from the heater, stress and temperature changes were monitored. Additional measurements of movements along major fractures on the surface and changes of water inflow in boreholes were carried out. The measured temperature distribution compares fairly well with the predicted. A maximum temperature of 333.90C was measured. The thermal conductivity of the rock mass has been calculated to lambda = 4.8 W/m0C. The thermally induced stresses in the rock mass do not correspond well with the predicted values. Results of measurements in boreholes of the in situ modulus are found to be about half of the laboratory determinations. Displacements of major fractures on the floor of the test drift are very small

  4. Uranium occurrences in the Granite Zone

    International Nuclear Information System (INIS)

    This report describes the work and results of the South Greenland Exploration Programme (Sydex) during the 1984 field season in the Granite Zone, and discusses the results and conclusions that can be drawn from them. It also contains a structural analysis of the Ivigtut-Julianehaab region, which will help in future exploration by indicating the likely directions of uraniferous faults and fractures. It also includes suggestions for future work with both exploration and scientific aspects. The project was carried out by the Geological Survey Greenland (GGU) in co-operation with Risoe National Laboratory. It was financed by the Danish Ministry of Energy. The structural analysis was carried out using previous geological maps, our own field observations and an analysis of lineament frequencies taken from aerial photographs and satellite images. Major lineaments in the region are due to E-W sinistral wrench faults and NE-SW normal faults. Analysis of the minor lineaments showed that the region could be divided into three blocks which have each reacted differently to the same regional stress field which was active throughout the Gardar period. A northern block which has been influenced by an older system of faults in the Archaean gneiss, a central block dominated by a graben, and a southern block where there is a change to a less intensively faulted area. 2 maps, 27 refs. (EG)

  5. Hydraulic fracturing in granite under geothermal conditions

    Science.gov (United States)

    Solberg, P.; Lockner, D.; Byerlee, J.D.

    1980-01-01

    The experimental hydraulic fracturing of granite under geothermal conditions produces tensile fracture at rapid fluid injection rates and shear fracture at slow injection rates and elevated differential stress levels. A sudden burst of acoustic emission activity accompanies tensile fracture formation whereas the acoustic emission rate increases exponentially prior to shear fracture. Temperature does not significantly affect the failure mechanism, and the experimental results have not demonstrated the occurrence of thermal fracturing. A critical result of these experiments is that fluid injection at intermediate rates and elevated differential stress levels increases permeability by more than an order of magnitude without producing macroscopic fractures, and low-level acoustic emission activity occurs simultaneously near the borehole and propagates outward into the specimen with time. Permeability measurements conducted at atmospheric pressure both before and after these experiments show that increased permeability is produced by permanent structural changes in the rock. Although results of this study have not demonstrated the occurrence of thermal fracturing, they suggest that fluid injection at certain rates in situ may markedly increase local permeability. This could prove critical to increasing the efficiency of heat exchange for geothermal energy extraction from hot dry rock. ?? 1980.

  6. The H2O content of granite embryos

    Science.gov (United States)

    Bartoli, Omar; Cesare, Bernardo; Remusat, Laurent; Acosta-Vigil, Antonio; Poli, Stefano

    2014-06-01

    Quantification of H2O contents of natural granites has been an on-going challenge owing to the extremely fugitive character of H2O during cooling and ascent of melts and magmas. Here we approach this problem by studying granites in their source region (i.e. the partially melted continental crust) and we present the first NanoSIMS analyses of anatectic melt inclusions (MI) hosted in peritectic phases of migmatites and granulites. These MI which totally crystallized upon slow cooling represent the embryos of the upper-crustal granites. The approach based on the combination of MI and NanoSIMS has been here tested on amphibolite-facies migmatites at Ronda (S Spain) that underwent fluid-present to fluid-absent melting at ˜700 °C and ˜5 kbar. Small (?5 ?m) crystallized MI trapped in garnet have been remelted using a piston-cylinder apparatus and they show leucogranitic compositions. We measure high and variable H2O contents (mean of 6.5±1.4 wt%) in these low-temperature, low-pressure granitic melts. We demonstrate that, when the entire population from the same host is considered, MI reveal the H2O content of melt in the specific volume of rock where the host garnet grew. Mean H2O values for the MI in different host crystals range from 5.4 to 9.1 wt%. This range is in rather good agreement with experimental models for granitic melts at the inferred P-T conditions. Our study documents for the first time the occurrence of H2O heterogeneities in natural granitic melts at the source region. These heterogeneities are interpreted to reflect the birth of granitic melts under conditions of “mosaic” equilibrium, where the distinct fractions of melt experience different buffering assemblages at the micro-scale, with concomitant differences in melt H2O content. These results confirm the need for small-scale geochemical studies on natural samples to improve our quantitative understanding of crustal melting and granite formation. The same approach adopted here can be applied to MI hosted in higher-temperature, granulite-facies rocks that represent the parents of many upper-crustal granites. This will result in a better understanding of formation and evolution of granitic magmas.

  7. The H2O content of granite embryos

    Science.gov (United States)

    Bartoli, Omar; Cesare, Bernardo; Remusat, Laurent; Acosta-Vigil, Antonio; Poli, Stefano

    2015-04-01

    Quantification of H2O contents of natural granites has been an on-going challenge owing to the extremely fugitive character of H2O during cooling and ascent of melts and magmas. Here we approach this problem by studying granites in their source region (i.e. the partially melted continental crust) and we present the first NanoSIMS analyses of anatectic melt inclusions (MI) hosted in peritectic phases of migmatites and granulites. These MI which totally crystallized upon slow cooling represent the embryos of the upper-crustal granites [1, 2, 3]. The approach based on the combination of MI and NanoSIMS has been here tested on amphibolite-facies migmatites at Ronda (S Spain) that underwent fluid-present to fluid-absent melting at ~700 °C and ~5 kbar. Small (? 5 µm) crystallized MI trapped in garnet have been remelted using a piston-cylinder apparatus and they show leucogranitic compositions. We measure high and variable H2O contents (mean of 6.5±1.4 wt%) in these low-temperature, low-pressure granitic melts. We demonstrate that, when the entire population from the same host is considered, MI reveal the H2O content of melt in the specific volume of rock where the host garnet grew. Mean H2O values for the MI in different host crystals range from 5.4 to 9.1 wt%. This range is in rather good agreement with experimental models for granitic melts at the inferred P-T conditions. Our study documents for the first time the occurrence of H2O heterogeneities in natural granitic melts at the source region [3]. These heterogeneities are interpreted to reflect the birth of granitic melts under conditions of "mosaic" equilibrium, where the distinct fractions of melt experience different buffering assemblages at the micro-scale, with concomitant differences in melt H2O content. These results confirm the need for small-scale geochemical studies on natural samples to improve our quantitative understanding of crustal melting and granite formation. The same approach adopted here can be applied to MI hosted in higher-temperature, granulite-facies rocks that represent the parents of many upper-crustal granites. This will result in a better understanding of formation and evolution of granitic magmas. [1] Cesare et al. (2009) Geology, 37, 627-630. [2] Bartoli et al. (2013) Geology, 41, 115-118. [3] Bartoli et al. (2014) EPSL, 395, 281-290.

  8. A hot spring in granite of the Western Tianshan, China

    International Nuclear Information System (INIS)

    The western Tianshan range is a major Cenozoic orogenic belt in central Asia exposing predominantly Paleozoic rocks including granite. Ongoing deformation is reflected by very rugged topography with peaks over 7000 m high. Active tectonic deformation is tied to an E-W trending fracture and fault system that sections the mountain chain into geologically diverse blocks that extend parallel to the orogen. In the Muzhaerte valley upwelling hot water follows such a fault system in the Muza granite. About 20 L min-1 Na-SO4-Cl water with a temperature of 55 deg. C having a total mineralization of about 1 g L-1 discharge from the hot spring. The water is used in a local spa that is frequented by the people of the upper Ili river area. Its waters are used for balneological purposes and the spa serves as a therapeutic institution. The major element composition of the hot water is dominated by Na and by SO4 and Cl, Ca is a minor component. Dissolved silica (1.04 mmol L-1) corresponds to a quartz-saturation temperature of 116 deg. C and a corresponding depth of the source of the water of about 4600 m. This temperature is consistent with Na/K and Na/Li geothermometry. The water is saturated with respect to fluorite and contains 7.5 mg L-1 F- as a consequence of the low Ca-concentration. The water is undersaturated with respect to the primary minerals of the reservoir granite at reservoir temperature causioir granite at reservoir temperature causing continued irreversible dissolution of granite. The waters are oversaturated with respect to Ca-zeolite minerals (such as stilbite and mesolite), and it is expected that zeolites precipitate in the fracture pore space and in alteration zones replacing primary granite. The stable isotope composition of O and H supports a meteoric origin of the water. The Cl/Br mass ratio of 1500 suggests that the salinity results from halite dissolution. Salts leached from powders of Muza granite show the same Cl/Br signature as the hot spring water. Sodium chloride is stored in fluid and solid inclusions in the granite, which have been introduced to quartz by ductile shearing and faulting related to ongoing orogenesis. The hot water remobilizes the salt that is continuously liberated by the tectonic deformation. Water-granite interaction contributes a thenardite-component (Na2SO4) to the major element composition by albite dissolution in H2SO4. The water-rock interaction along faults and fractures transforms and alters Muza granite to a low-temperature epigranite

  9. The 'Granite' collegial mission of dialogue. Report; Mission collegiale de concertation Granite. Rapport

    Energy Technology Data Exchange (ETDEWEB)

    Boisson, P.; Huet, Ph.; Mingasson, J

    2000-06-01

    The aim of the 'Granite' collegial mission of dialogue is to inform the French authorities, associations and population about the project of construction of an underground laboratory for the study of the disposal of high level and long-life radioactive wastes in a granitic environment. The aim of the dialogue was not to select a site but to collect the public reactions and advices about such a project. However, such a dialogue has partially failed because of a misunderstanding of the population about the aims of the mission. However, the mission has collected many point of views and questions which are developed in this report. The first and second chapters recall the process of the mission and its progress, while a third chapter stresses on the questions asked by the public and which concern the fear of nuclear wastes and the incompatibility between the disposal of wastes and the socio-economical development of the region concerned. Thanks to the lessons drawn from this experience, the mission has formulated some recommendations (chapter 4) concerning the need for a better information of the population about any topic in relation with the radioactive wastes. Some complementary information is provided in appendixes. (J.S.)

  10. Novel Approach for Hybrid Intrusion Detection System

    Directory of Open Access Journals (Sweden)

    Ravi Kishore Sharma, Mr. Gajendra Singh Chandel

    2012-11-01

    Full Text Available This Paper titled “Novel Approach for Intrusion Detection System” is an intrusion detection system (IDS proposed by analyzing the principle of the intrusion detection system based on host and network. Basically this paper is to develop host based cum network based intrusion detection system for Microsoft Windows XP environment. Proposed concept that had used in this was applying intrusion detection rule matching technique on the Security Log File and Event Log File in Microsoft Windows XP for the Host based IDS module. The intrusion had identified when there was finding of attacks that is creating with these two file in Microsoft Windows XP. In Network based IDS module DOS, U2R, Rejected (RST attacks are finding during packet capturing in network. Moreover, the security and performance of the proposed IDS is also estimated. The proposed IDS approve the effectiveness of the proposed method, and it shows advantages of host based as well as network based security. The proposed model of hybrid IDSs offers several advantages over alternative systems. First of all it provided higher security, it supported high availability and scalability, and most important thing it produced good results in terms of normal and abnormal behaviors of arrived packet. The proposed model includes integration of individual components to produced batter results. It supports to a system/network administrator the privileges for finding the intrusions which is reliable, secure and fast. The proposed model of hybrid IDS implemented in short time and at a low cost. It also provides a best user interface.

  11. Geochemistry and zircon U-Pb geochronology of granitic rocks in the Buqingshan tectonic mélange belt, northern Tibet Plateau, China and its implications for Prototethyan evolution

    Science.gov (United States)

    Li, Ruibao; Pei, Xianzhi; Li, Zuochen; Pei, Lei; Liu, Chengjun; Chen, Youxin; Chen, Guochao; Liu, Zhanqing; Yang, Jie

    2015-06-01

    The Yikehalaer intrusives are distributed in the Buqingshan tectonic mélange belt at the southern margin of East Kunlun, China. They tectonically intruded the conglomerate of Permian Gequ Formation to the south and the marble of Mesoproterozoic Kuhai Group to the north. These intrusives mainly consist of off-white coarse- and fine-grained granodiorite and granite. U-Pb dating of zircons from the intrusive samples yielded weighted mean 206Pb/238U ages of 436 ± 7 Ma and 437 ± 6 Ma, indicating Early Silurian crystallization age. The intrusives are high-silica, Na-rich, I-type calc-alkalic rocks. They are divisible into two subgroups on the basis of their trace element content: adakitic rocks in the northern part and normal calc-alkalic arc rocks in the southern part. Rocks in the northern part exhibit high Sr (280-493 ppm), low Y (3.8-11.7 ppm), high Sr/Y ratios (23.9-125.0), high light rare earth elements (LREE)/ heavy rare earth elements (HREE) (15.1-35.7), and invisible Eu/Eu?. They resemble adakites formed by slab melting in subduction zones. However, the rocks in the southern part possess the attributes of normal arc rocks. In addition, the ?Hf(t) values of the intrusives are consistently positive (0.6-7.6), implying that they were generated by melting of an isotopically depleted mantle source, with insignificant contributions from crustal materials. The source residues likely contained 10-20% garnet and hornblende, and plagioclase was either absent or totally consumed during partial melting. Combining the regional tectonic data, we conclude that the Buqingshan paleo-ocean may have started to subduct in Middle Cambrian until Early Silurian (436 Ma), generating an important adakitic magma event during the late stage of oceanic crust subduction. Moreover, the Proto-Tethyan Ocean closed, and the Bayan Har, East Kunlun, and Qaidam blocks collided during the Middle-Late Silurian.

  12. A comparison of fracture styles in two granite bodies of the Superior Province

    International Nuclear Information System (INIS)

    A quantitative comparison is made between fracture styles in two late Archean instrusions of the Superior Province - the Lac du Bonnet Batholith (LDBB) and Eye-Dashwa Pluton (EDP). These instrusions have a similar geological setting, similar mineral and chemical composition, and similar physical properties but vary markedly in volume (LDBB = 9060 km3; EDP = 122 km3). The fracture style of the LDBB consists of mainly low-angle thrust faults within otherwise poorly fractured granite. Subvertical fractures are restricted to within 200 m of surface or zones encompassing the thrust faults. The mineral assemblage chlorite - iron oxide - carbonate is widespread in fractures. In contrast, fractures of the EDP are closely spaced, variably oriented, pervasive to depth, and dominated by subvertical transcurrent faults. Epidote is an abundant fracture-filling material. Most fractures formed in response to Early Proterozoic compression under low-greenschist conditions in the LDBB and upper-greenschist conditions in the EDP. Fractures in both intrusions were subsequently rejuvenated (clay - iron oxide filling materials) without appreciable modification to fracture styles. The presence of a strong planar fabric at one site, variation in the intensity of Early Proterozoic tectonism, and prolonged plastic deformation in the large LDBB are cited as possible causes for the observed variation in fracture styles

  13. The intrusive complexof the Island of Giglio: geomagnetic characteristics of plutonic facies with low susceptibility contrast

    Directory of Open Access Journals (Sweden)

    R. Cavallini

    1998-06-01

    Full Text Available Two main plutonic facies characterize the intrusive complex of the Island of Giglio, and the trend of their contact at depth has been modelled using a 2D½ analysis based on a detailed geomagnetic survey in order to verify the geological hypothesis of the subsurface geometry of this contact. The magnetic anomaly connected with the discontinuity is quite low, due to the small difference between the magnetic susceptibilities of the two granitic facies. Development of this model of inversion of the magnetic field, which is in good agreement with the geological interpretation, was made possible by: 1 accurate control of the geomagnetic time variations and consequent temporal reduction, 2 a very low level of the artificial magnetic noise, 3 high density of the magnetic survey, 4 detailed knowledge of the mapped geologic contact between facies and of their petrologic characteristics, and 5 direct local measurements of the magnetic susceptibilities of the key lithologies. The model shows the trends of the geological contact, as projected in three E-W sections, that dips eastward in the range between 210 and 540, supporting the geologic hypothesis that the Pietrabona facies represents an external shell of the shallowly emplaced Giglio monzogranite intrusion.

  14. An overview to Software Architecture in Intrusion Detection System

    CERN Document Server

    Bahrami, Mehdi

    2012-01-01

    Network intrusion detection systems provide proactive defense against security threats by detecting and blocking attack-related traffic. This task can be highly complex, and therefore, software based network intrusion detection systems have difficulty in handling high speed links. This paper reviews of many type of software architecture in intrusion detection systems and describes the design and implementation of a high-performance network intrusion detection system that combines the use of software-based network intrusion detection sensors and a network processor board. The network processor acts as a customized load balancing splitter that cooperates with a set of modified content-based network intrusion detection sensors in processing network traffic.

  15. Effective analysis of cloud based intrusion detection system

    Directory of Open Access Journals (Sweden)

    Sanjay Ram

    2012-08-01

    Full Text Available The goal of IDS is to analyze events on the network and identify attacks. The increasing number of network security related incidents makes it necessary for organizations to actively protect their sensitive data with the installation of intrusion detection systems (IDS. People are paid more attention on intrusion detection which as an important computer network security technology. According to the development trend of intrusion detection, detecting all kinds of intrusions effectively requires a global view of the monitored network, Here, discuss about new intrusion detection mechanism based on cloud computing, which can make up for the deficiency of traditional intrusion detection, and proved to be great scalable.

  16. Category-Based Intrusion Detection Using PCA

    Directory of Open Access Journals (Sweden)

    Gholam Reza Zargar

    2012-10-01

    Full Text Available Existing Intrusion Detection Systems (IDS examine all the network features to detect intrusion or misuse patterns. In feature-based intrusion detection, some selected features may found to be redundant, useless or less important than the rest. This paper proposes a category-based selection of effective parameters for intrusion detection using Principal Components Analysis (PCA. In this paper, 32 basic features from TCP/IP header, and 116 derived features from TCP dump are selected in a network traffic dataset. Attacks are categorized in four groups, Denial of Service (DoS, Remote to User attack (R2L, Remote to User attack (U2R and Probing attack. TCP dump from DARPA 1998 dataset is used in the experiments as the selected dataset. PCA method is used to determine an optimal feature set to make the detection process faster. Experimental results show that feature reduction can improve detection rate for the category-based detection approach while maintaining the detection accuracy within an acceptable range. In this paper KNN classification method is used for the classification of the attacks. Experimental results show that feature reduction will significantly speed up the train and the testing periods for identification of the intrusion attempts.

  17. Intrusion problematic during water supply systems’ operation

    Directory of Open Access Journals (Sweden)

    Jesus Mora-Rodriguez, P. Amparo López-Jimenez, Helena M. Ramos

    2011-05-01

    Full Text Available Intrusion through leaks occurrence is a phenomenon when external fluid comes into water pipe systems. This phenomenon can cause contamination problems in drinking pipe systems. Hence, this paper focuses on the entry of external fluids across small leaks during normal operation conditions. This situation is especially important in elevated points of the pipe profile. Pressure variations can origin water volume losses and intrusion of contaminants into the drinking water pipes. This work focuses in obtaining up the physical representation on a specific case intrusion in a pipe water system. The combination of two factors is required to generate this kind of intrusion in a water supply system: on one hand the existence of at least a leak in the system; on the other hand, a pressure variation could occur during the operation of the system due to consumption variation, pump start-up or shutdown. The potential of intrusion during a dynamic or transient event is here analyzed. To obtain this objective an experimental case study of pressure transient scenario is analyzed with a small leak located nearby the transient source.

  18. Estrogen Therapy Has No Long-Term Effect on Cognition in Younger Postmenopausal Women

    Science.gov (United States)

    ... Estrogen therapy has no long-term effect on cognition in younger postmenopausal women NIH-funded study finds ... reasons that hormone treatments had different effects on cognition in older and younger postmenopausal women. WHIMSY is ...

  19. Structural, Petrographic and Geochemical Characteristics of Mafic Dikes Intrusive in Metasedimentary Rocks of the Crixás Greenstone Belt, Goiás

    Directory of Open Access Journals (Sweden)

    Hardy Jost

    2010-10-01

    Full Text Available Mafic dikes and stocks are a common feature in the Archean terrain of Goiás, Central Brazil, where they occur asswarms of 2.3 - 2.5 Ga within the granite-gneiss complexes (2.8 e 2.7 Ga, as well as intrusions related to the komatiite andbasalt flows of the greenstone belts lower stratigraphic units, but were unknown within the upper metasedimentary units.Detailed study of core sections from several drill-sites in the area of the Crixás greenstone belt gold deposits showed thatdike intrusion occurred after the main Paleoproterozoic deformation and metamorphism of the metasedimentary units,and literature data indicate that the magmatic zircons from the dikes yielded an age of 2,170 ± 17 Ma. Petrographic andgeochemical data show that they have the composition of epicratonic high-Ti diabases, which are similar to the largecontinental flood basalts of the Paraná Basin. The age of the intrusions may be correlated with the short time-interval of theRhyacian (2.20 to 2.17 Ga, during which successive localized episodes of mantle plume volcanism occurred on the Earth.

  20. The instrumental neutron-activation analysis of granites from the Bushveld Complex

    International Nuclear Information System (INIS)

    Three methods of instrumental neutron-activation analysis, 14MeV, reactor thermal, and reactor epithermal, are compared for the analysis of granites form the Bushveld Complex. A total of 34 elements can be determined in the granites by these methods. Samples from the Zaaiplaats area were analysed by thermal neutron activation, and 22 elements were determined in all of them. These elements were used to distinguish between the mineralized Bobbejaankop and Lease granites and the Main granite by the use of multivariate statistics. The Bobbejaankop granite appears as a more-differentaited rock carrying greater amounts of the incompatible elements than does the Main granite

  1. Smolt Monitoring at the Head of Lower Granite Reservoir and Lower Granite Dam, 2005 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Buettner, Edwin W.; Putnam, Scott A. [Idaho Department of Fish and Game

    2009-02-18

    This project monitored the daily passage of Chinook salmon Oncorhynchus tshawytscha, steelhead trout O. mykiss, and sockeye salmon O. nerka smolts during the 2005 spring out-migration at migrant traps on the Snake River and Salmon River. In 2005 fish management agencies released significant numbers of hatchery Chinook salmon and steelhead trout above Lower Granite Dam that were not marked with a fin clip or coded-wire tag. Generally, the age-1 and older fish were distinguishable from wild fish by the occurrence of fin erosion. Age-0 Chinook salmon are more difficult to distinguish between wild and non-adclipped hatchery fish and therefore classified as unknown rearing. The total annual hatchery spring/summer Chinook salmon catch at the Snake River trap was 0.34 times greater in 2005 than in 2004. The wild spring/summer Chinook catch was 0.34 times less than the previous year. Hatchery steelhead trout catch was 0.67 times less than in 2004. Wild steelhead trout catch was 0.72 times less than the previous year. The Snake River trap collected 1,152 age-0 Chinook salmon of unknown rearing. During 2005, the Snake River trap captured 219 hatchery and 44 wild/natural sockeye salmon and 110 coho salmon O. kisutch of unknown rearing. Differences in trap catch between years are due to fluctuations not only in smolt production, but also differences in trap efficiency and duration of trap operation associated with flow. Trap operations began on March 6 and were terminated on June 3. The trap was out of operation for a total of one day due to heavy debris. FPC requested that the trap be restarted on June 15 through June 22 to collect and PIT tag age-0 Chinook salmon. Hatchery Chinook salmon catch at the Salmon River trap was 1.06 times greater and wild Chinook salmon catch was 1.26 times greater than in 2004. The hatchery steelhead trout collection in 2005 was 1.41 times greater and wild steelhead trout collection was 1.27 times greater than the previous year. Trap operations began on March 6 and were terminated on May 17 due to high flows. There were two days when the trap was taken out of service because of mechanical failure. Travel time (d) and migration rate (km/d) through Lower Granite Reservoir for passive integrated transponder (PIT) tagged Chinook salmon and steelhead trout marked at the Snake River trap were affected by discharge. Statistical analysis of 2005 data detected a relation between migration rate and discharge for hatchery Chinook but was unable to detect a relation for wild Chinook. The inability to detect a migration rate discharge relation for wild Chinook salmon was caused by a lack of data. For hatchery Chinook salmon there was a 1.8-fold increase in migration rate between 50 and 100 kcfs. For steelhead trout tagged at the Snake River trap, statistical analysis detected a significant relation between migration rate and lower Granite Reservoir inflow discharge. For hatchery and wild steelhead trout, there was a 2.2-fold and a 2.2-fold increase in migration rate, respectively, between 50 and 100 kcfs. Travel time and migration rate to Lower Granite Dam for fish marked at the Salmon River trap were calculated. Statistical analysis of the 2005 data detected a significant relation between migration rate and Lower Granite Reservoir inflow discharge for hatchery Chinook salmon, wild Chinook salmon, hatchery steelhead trout, and wild steelhead trout. Migration rate increased 4.2-fold for hatchery Chinook salmon, 2.9-fold for wild Chinook salmon and 2.5-fold for hatchery steelhead, and 1.7-fold for wild steelhead as discharge increased between 50 kcfs and 100 kcfs. Fish tagged with PIT tags at the Snake River and Salmon River traps were interrogated at four dams with PIT tag detection systems (Lower Granite, Little Goose, Lower Monumental and McNary dams). Because of the addition of the fourth interrogation site (Lower Monumental) in 1993 and the installation of the Removable Spillway Weir at Lower Granite Dam in 2001, caution must be used in comparing cumulative interrogation data. Cumulative interrogations at the fo

  2. Early Paleozoic intrusive rocks from the eastern Qilian orogen, NE Tibetan Plateau: Petrogenesis and tectonic significance

    Science.gov (United States)

    Yang, He; Zhang, Hongfei; Luo, Biji; Zhang, Jie; Xiong, Ziliang; Guo, Liang; Pan, Fabin

    2015-05-01

    Voluminous Early Paleozoic intrusive rocks occur in the Qilian orogenic belt, northeastern margin of the Tibetan Plateau. Their petrogenesis can provide insights into the tectonic evolution of Qilian and its adjacent areas. This paper carries out an integrated study of U-Pb zircon dating, geochemical and Sr-Nd-Hf isotopic compositions for the Bamishan and Heishishan plutons in the eastern Qilian orogen. Both the Bamishan and Heishishan plutons consist of mafic, intermediate and felsic intrusive rocks. U-Pb zircon dating yielded the magma crystallization ages of 459-449 Ma for the Bamishan pluton and 447-438 Ma for the Heishishan pluton. Their geochemical and Sr-Nd-Hf isotopic data show that the parental magmas of the Bamishan monzogranites and quartz diorites were generated by slab (MORB and overlying sediments) melting. The Bamishan hornblende gabbros have extremely high Cr (1159-1163 ppm), Ni (220-353 ppm) and Mg# (73-74), indicating a cumulate origin. The Heishishan granodiorite-granite has adakitic geochemical signatures and they were produced by partial melting of the mafic lower crust. The Heishishan hornblende gabbro and quartz diorites were derived from the enriched lithospheric mantle metasomatized by subduction-related fluid/melt. In light of the available data, we propose that there was an Early Paleozoic ocean basin between the Central-South Qilian and Qaidam-West Qiling belts. The northward closure of this basin and subsequent continental collision and post-collisional processes resulted in the generation of the Early Paleozoic magmatism in the eastern Central Qilian. The Late Ordovician to Early Silurian (~ 460-440 Ma) intrusive rocks in the eastern Central Qilian formed in a post-collisional setting. A slab break-off model may account for the magma generation.

  3. Study on distribution coefficient for cesium between granite and water

    International Nuclear Information System (INIS)

    As a part of safety evaluation of geological disposal, distribution coefficient, Kd has been measured in the laboratory. The Kd for Cs between solution and granite which is one of the candidates of igneous rocks for repository, has been measured by typical batch method. The weight of Cs adsorbed on the unit weight of granite is constant in the case that the concentration of Cs in solution is constant. There is no dependancy of the weight of Cs adsorbed on the unit weight of granite on the surface gross area of granite at equilibrium condition. Consequently it appears that the Kd, which is calculated from the weight of Cs adsorbed on granite, is constant in the case that the concentration of Cs in solution is constant. The value of Kd at equilibrium condition varies from 20(ml/g) to 1(ml/g) in the range of high Cs concentration solution. On the other hand in the range of low Cs concentration, it seems that the value of Kd is almost constant, independently of the Cs concentrations. (author)

  4. Modelling radiation dose for Brazilian granite as building material

    International Nuclear Information System (INIS)

    Granite is a term to describe magmatic rocks consisting of quartz and feldspar (plagioclase and potassium feldspar) and, incidentally, biotite, muscovite, amphibole and rarely pyroxene. These rocks are used as buildings material as ornamental countertops and floors due to characteristics like coloration and polishing. Some of their accessory minerals are associated with uranium and thorium and consequently to their daughter radionuclides, as radium and radon. This study aims to calculate doses due radon and gamma radiation for people inside buildings with granite floor and countertops. In a previous study about Brazilian granite, samples of the three types of the stones were collected and processed and the concentrations of activity of natural radionuclides were determined. The doses due to the use of the samples as floor and countertops in Brazilian buildings were assessed with the Radar's-Build software. The doses were compared and the granite Crema Bordeaux showed the higher contribution to radon and external dose than the others granite samples that showed similar values of dose. 226Ra and 40K were the major responsible by the external dose. (author)

  5. Uranium distribution in Brazilian granitic rocks. Identification of uranium provinces

    International Nuclear Information System (INIS)

    The research characterized and described uranium enriched granitoids in Brazil. They occur in a variety of tectonic environments and are represented by a variety granite types of distinct ages. It may be deduced that in general they have been generated by partial melting process of continental crust. However, some of them, those with tonality composition, indicate a contribution from mantle derived materials, thus suggesting primary uranium enrichment from the upper mantle. Through this study, the identification and characterization of uranium enriched granite or uranium provinces in Brazil can be made. This may also help identify areas with potential for uranium mineralization although it has been note that uranium mineralization in Brazil are not related to the uranium enrichment process. In general the U-anomalous granitoids are composed of granites with alkaline composition and granite ''sensu strictu'' which comprise mainly of syenites, quartz-syenites and biotite-hornblende granites, with ages between 1,800 - 1,300 M.a. The U-anomalous belongings to this period present high Sr initial ratios values, above 0.706, and high Rb contents. Most of the U-enriched granitoids occur within ancient cratonic areas, or within Early to Mid-Proterozoic mobile belts, but after their cratonization. Generally, these granitoids are related to the border zones of the mobile belts or deep crustal discontinuity. Refs, 12 figs, 3 tabs

  6. An Architecture of Hybrid Intrusion Detection System

    Directory of Open Access Journals (Sweden)

    Kanubhai K Patel

    2012-12-01

    Full Text Available Intrusion Detection System (IDS is renowned and widely-deployed security tool to detect attacks and malicious activities in information system. It is an essential element of any contemporary information system. There are mainly two techniques for intrusion detection: i signature-based (misuse detection and ii anomaly-based detection technique. Both the techniques have their advantages and disadvantages. This paper presents research from an ongoing study on the use of features of both the intrusion detection techniques to design a novel and efficient hybrid IDS. An architecture and implementation details of our hybrid IDS are presented. Furthermore, unique characteristics of our hybrid IDS are described. This paper concludes with future research directions and challenges in IDS.

  7. Trusted Computing Based Collaborative Intrusion Detection System

    Directory of Open Access Journals (Sweden)

    Jamalul-Lail Ab Manan

    2012-01-01

    Full Text Available Collaboration and information sharing has obliged participating parties to look for improved detection accuracy and reaction speed in Distributed Intrusion Detection Systems (DIDS solutions. This is mainly due to the increasing number of attacks as well as increasingly sophisticated intrusions and more alarmingly various critical components of a system can be targeted. This is further exasperated by the fact that most DIDS models do not consider the attacks targeting the collaborative network itself. We specifically find this issue to be very critical and hence in this paper we propose a trust aware DIDS simulation model that is capable of categorizing each participating IDS expertise (i.e. speciality and competence, therefore helps collaborating organizations to consult our simulation model for choosing the right candidate for any type of intrusion. We call our Model as Consultative Trusted Computing-based Collaborative IDS (CTC IDS. We utilize the Trusted Platform Module (TPM for integrity evaluation and fine-tuning peer evaluation.

  8. Advances in Intrusion Detection System for WLAN

    Directory of Open Access Journals (Sweden)

    Ravneet Kaur

    2011-10-01

    Full Text Available A wireless network is not as secure as compare the wired network because the data is transferred on air so any intruder can use hacking techniques to access that data. Indeed it is difficult to protect the data and provide the user a secure information system for lifetime. An intrusions detection system aim to detect the different attacks against network and system. An intrusion detection system should be capable for detecting the misuse of the network whether it will be by the authenticated user or by an attacker. Cross layer based technique help to make decision based on two layer physical layer where we compute RSS value and on MAC layer where one compute RTS-CTS time taken. This will reduce the positive false rate.They detect attempts and active misuse either by legitimate users of the information systems or by external. The paper has higlighted the advances in intrusion detection in wireless local area network.

  9. Applying Fast String Matching to Intrusion Detection

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, M. E. (Mike E. ); Varghese G. (George)

    2001-01-01

    The performance of signature-based network intrusion detection tools is dominated by the string matching of packets against many signatures. In this paper we study how the popular intrusion detecton system Snort can be best optimized to utilize different string matching algorithms. We analyze the performance of Snort's current string matching algorithm, Boyer-Moore, and several alternate algorithms. We show that no single algorithm is fastest in the context of a real Snort rule set. Instead, we develop a hybrid system that utilizes three different search algorithms, including one new algorithm presented in this paper. The result is a system that matches many common packets 5 times faster with an average speedup of 50%. While the context of our analysis is intrusion detection, other problem domains such as virus scanning, firewalls, and layer seven switches benefit from our work.

  10. Geochemistry of A-type granites in the Huangshaping polymetallic deposit (South Hunan, China): Implications for granite evolution and associated mineralization

    Science.gov (United States)

    Li, Huan; Watanabe, Koichiro; Yonezu, Kotaro

    2014-07-01

    The Huangshaping granites in Hunan Province, South China were investigated for their geochemical characteristics. Three types of granites have been petrographically identified: quartz porphyry, granophyre, and granite porphyry. Whole rock geochemistry suggests that the Huangshaping granites, especially the granite porphyry, exhibit typical A-type granite characteristics with their enrichment in Si, Rb, U, Th, and Nb and significant depletion in Ba, Sr, Ti, Eu, and P. Based on the Al, Y and Zr contents as well as the REE patterns of the rocks investigated, the quartz porphyry and the granophyre are classified as A1 type alkaline granites whereas the granite porphyry is considered as A2 type aluminous granite. Whole rock and quartz/feldspar O isotope data yields a wide range of ?18OSMOW values (11.09-26.32‰). The granites are characterized by high radiogenic Pb isotopic composition. The present-day whole rock Pb isotopic ratios are 206Pb/204Pb = 18.706-19.155, 207Pb/204Pb = 15.616-15.711 and 208Pb/204Pb = 38.734-39.296. Combining the O-Pb isotope compositions with major, trace and REE geochemistry and regional geology characteristics, the Huangshaping granites were determined to resemble within-plate granites that were mainly derived from a felsic infracrustal source related to continental extension. The magma source of the quartz porphyry and the granophyre may have been generated from deeper depths, and then ascended rapidly with limited water content and low oxygen fugacity, which contributed to Cu, Pb and Zn mineralization. On the other hand, the magma that generated the granite porphyry may have ascended relatively slower and experienced pronounced crystal fractionation, upper-crustal basement rock contamination (assimilation) and wall-rock interaction, producing the Sn- and W-rich granite porphyry. This study reveals the crustal extension process and associated magmatic-metallogenic activities during 180-150 Ma in South Hunan.

  11. Geochemistry, zircon U-Pb geochronology and Hf isotopes of granites in the Baoshan Block, Western Yunnan: Implications for Early Paleozoic evolution along the Gondwana margin

    Science.gov (United States)

    Dong, Meiling; Dong, Guochen; Mo, Xuanxue; Santosh, M.; Zhu, Dicheng; Yu, Junchuan; Nie, Fei; Hu, Zhaochu

    2013-10-01

    The leucogranites in the Baoshan Block of the Tethyan belt in Western Yunnan, are composed mainly of two-mica granite with subordinate muscovite granite. Here we present zircon U-Pb ages from four intrusions that show ages of 448-476 Ma suggesting that these rocks were emplaced during the Ordovician. The leucogranites are high-K calc-alkaline and strongly peraluminous, with K2O/Na2O > 1 and A/CNK = 1.12-1.54. These rocks are enriched in large-ion lithophile elements (LILEs) and light rare-earth elements (LREEs) [(La/Yb)N = 1.13-32.4] and Pb, and are depleted in high field-strength elements (HFSEs). They show similar chondrite-normalized REE patterns, with negative Eu anomalies (Eu/Eu* = 0.03-0.46). A wide range of zircon ?Hf(t) values (- 9.6 to - 2.6) and varying Hf-isotope crustal model ages (2.1-1.6 Ga) are also observed. The geochemical signatures indicate that the leucogranites are S-type granites derived mainly from the anatexis of ancient crustal materials. The ages, geochemistry and tectonics in the Baoshan Block and the Lhasa Terrane are closely comparable, suggesting that the Baoshan Block might represent part of an Early Paleozoic magmatic arc in the Gondwana continental margin facing the proto-Tethyan Ocean. The Pinghe granites of the early phase in the Baoshan Block which are coeval with the Cambrian magmatism (ca. 492 Ma) identified in the central and southern Lhasa subterranes can be interpreted as products of the slab break-off associated with the subduction of proto-Tethyan oceanic lithosphere. However, the late leucogranite stocks are analogous to the North Himalayan leucogranites, which formed in a short-lived extensional setting caused by the slab break-off associated with the subduction-collision system.

  12. Perceived illness intrusion among patients on hemodialysis

    Directory of Open Access Journals (Sweden)

    Bapat Usha

    2009-01-01

    Full Text Available Dialysis therapy is extremely stressful as it interferes with all spheres of daily acti-vities of the patients. This study is aimed at understanding the perceived illness intrusion among pa-tients on hemodialysis (HD and to find the association between illness intrusion and patient demo-graphics as well as duration of dialysis. A cross sectional study involving 90 patients with chronic kidney disease (CKD stage V, on HD was performed during the period from 2005 to 2006. The subjects included were above 18 years of age, willing, stable and on dialysis for at least two months. Patients with psychiatric co-morbidity were excluded. A semi-structured interview schedule covering socio-demographics and a 13 item illness intrusion checklist covering the various aspects of life was ca-rried out. The study patients were asked to rate the illness intrusion and the extent. The data were ana-lyzed statistically. The mean age of the subjects was 50.28 ± 13.69 years, males were predominant (85%, 73% were married, 50% belonged to Hindu religion, 25% had pre-degree education, 25% were employed and 22% were housewives. About 40% and 38% of the study patients belonged to middle and upper socio-economic strata respectively; 86% had urban background and lived in nuclear fami-lies. The mean duration on dialysis was 24 ± 29.6 months. All the subjects reported illness intrusion to a lesser or greater extent in various areas including: health (44%, work (70% finance (55%, diet (50% sexual life (38% and psychological status (25%. Illness had not intruded in areas of rela-tionship with spouse (67%, friends (76%, family (79%, social (40% and religious functions (72%. Statistically significant association was noted between illness intrusion and occupation (P= 0.02.

  13. An automatically tuning intrusion detection system.

    Science.gov (United States)

    Yu, Zhenwei; Tsai, Jeffrey J P; Weigert, Thomas

    2007-04-01

    An intrusion detection system (IDS) is a security layer used to detect ongoing intrusive activities in information systems. Traditionally, intrusion detection relies on extensive knowledge of security experts, in particular, on their familiarity with the computer system to be protected. To reduce this dependence, various data-mining and machine learning techniques have been deployed for intrusion detection. An IDS is usually working in a dynamically changing environment, which forces continuous tuning of the intrusion detection model, in order to maintain sufficient performance. The manual tuning process required by current systems depends on the system operators in working out the tuning solution and in integrating it into the detection model. In this paper, an automatically tuning IDS (ATIDS) is presented. The proposed system will automatically tune the detection model on-the-fly according to the feedback provided by the system operator when false predictions are encountered. The system is evaluated using the KDDCup'99 intrusion detection dataset. Experimental results show that the system achieves up to 35% improvement in terms of misclassification cost when compared with a system lacking the tuning feature. If only 10% false predictions are used to tune the model, the system still achieves about 30% improvement. Moreover, when tuning is not delayed too long, the system can achieve about 20% improvement, with only 1.3% of the false predictions used to tune the model. The results of the experiments show that a practical system can be built based on ATIDS: system operators can focus on verification of predictions with low confidence, as only those predictions determined to be false will be used to tune the detection model. PMID:17416165

  14. Perceived illness intrusion among patients on hemodialysis

    International Nuclear Information System (INIS)

    Dialysis therapy is extremely stressful as it interferes with all spheres of daily activities of the patients. This study is aimed at understanding the perceived illness intrusion among patients on hemodialysis (HD) and to find the association between illness intrusion and patient demo-graphics as well as duration of dialysis. A cross sectional study involving 90 patients with chronic kidney disease (CKD) stage V, on HD was performed during the period from 2005 to 2006. The subjects included were above 18 years of age, willing, stable and on dialysis for at least two months. Patients with psychiatric co-morbidity were excluded. A semi-structured interview schedule covering sociodemographics and a 13 item illness intrusion checklist covering the various aspects of life was carried out. The study patients were asked to rate the illness intrusion and the extent. The data were analyzed statistically. The mean age of the subjects was 50.28 + - 13.69 years, males were predominant (85%), 73% were married, 50% belonged to Hindu religion, 25% had pre-degree education, 25% were employed and 22% were housewives. About 40% and 38% of the study patients belonged to middle and upper socio-economic strata respectively; 86% had urban background and lived in nuclear families. The mean duration on dialysis was 24 + - 29.6 months. All the subjects reported illness intrusion to a lesser or greater extent in various areas including: health (44%), work (70%) finance (55%), diet (50%) sexuawork (70%) finance (55%), diet (50%) sexual life (38%) and psychological status (25%). Illness had not intruded in areas of relationship with spouse (67%), friends (76%), family (79%), social (40%) and religious functions (72%). Statistically significant association was noted between illness intrusion and occupation (P= 0.02). (author)

  15. Mantle fluid metallogeny of granite-type uranium deposits in northern Guangdong

    International Nuclear Information System (INIS)

    Both Guidong and Zhuguang composites in northern Guangdong Province consist of Indosinian and Yanshanian granite bodies. The two most well-known granite-type uranium ore fields in China, Xiazhuang and Changjiang, are located in the eastern parts of the the two composites, respectively. Studies on H, O, C, Pb, Sr, and Nd isotopes of uranium deposits Xiwang, Shituling and Xianshi within the Xiazhuang ore field and deposit Mianhuakeng within the Changjiang ore field showed that ore-forming fluid had DH2O of -97?-4.1% and ?18OH2O of 8.1?0.06%; post-ore fluid had ?DH2O of -71?-5% and ?DH2O of 2.0?-0.94%. After being compared with various fluids, these data suggested the ore-forming fluids were mainly composed of mantle fluid, whereas in the post-mineralization fluids, addition of fluids with meteoric water origin became evident or even dominant. Calcites from ore veins had ?13C of -9.2?-0.31%, indicating mantle origin of ?CO2. Studies of Pb, Sr and Nd isotopes revealed that ore-forming materials were a mixture of metal elements coming from granites, mafic dikes and basement metamorphic rocks. Mantle fluid metallogeny of these uranium deposits was compatible with the following geological facts. The deposits in Xiazhuang and Changjiang ore fields fell into super large ones. Within the ore fields, there were many mafic dikes of various groupsfic dikes of various groups and strike directions. Fault-depression basins were developed outside the granite composites. The timing and space of ore formation were closely related to the extension tectonic event (or emplacement of mafic dikes. The ore components were characterized by multiple origins. Both permissively and zoned distributions of alkaline alterations were strong and the mineralization fluids were originated from the mantle. The mineralization model could be described as follows: Fluids from Dehydration and degassing of subducting slabs in the late Mesozoic altered the mantle in the mantle wedge by metasomatism to form mantle fluids which finally flew into crust through deep extensional tectonic activities (or intrusion of mafic dike magmas). During moving up process, the mantle fluids which were enriched in alkali and ?CO2 interacted with the crustal rocks (especially uranium-rich rocks), resulting in alkaline alteration of crustal rocks and mobilizing uranium and other metals in the rocks. As a result, the mantle-derived fluids gradually became uranium-rich fluids. Deposition of pitchblende during late evolution stages of the mantle fluids was related with following factors: 1) mixing of the ore-forming fluids with fluids of meteoric-water origin so as to change the physicochemical conditions of the fluids, 2) boiling of the fluids when they entering low pressure environment and thus escaping of CO2 to lead to decomposition of the uranyl-carbonate ions in the fluids, 3) interaction between uranyl-ion bearing fluids and reducer bearing mafic dikes.. (authors)

  16. A network-based realtime intrusion detection system

    International Nuclear Information System (INIS)

    The author first reviews the background of Intrusion Detection (ID), then discusses the models and classifications of Intrusion Detection System (IDS). After detail the basic concepts to realize network-based realtime IDS, the analysis of authors' work are presented

  17. Automated electronic intruder simulator for evaluation of ultrasonic intrusion detectors

    International Nuclear Information System (INIS)

    An automated electronic intruder simulator for testing ultrasonic intrusion detectors is described. This simulator is primarily intended for use in environmental chambers to determine the effects of temperature and humidity on the operation of ultrasonic intrusion detectors

  18. Adaptive intrusion data system (AIDS) software routines

    International Nuclear Information System (INIS)

    An Adaptive Intrusion Data System (AIDS) was developed to collect information from intrusion alarm sensors as part of an evaluation system to improve sensor performance. AIDS is a unique digital data-compression, storage, and formatting system; it also incorporates a capability for video selection and recording for assessment of the sensors monitored by the system. The system is software reprogrammable to numerous configurations that may be used for the collection of environmental, bilevel, analog, and video data. This report describes the software routines that control the different AIDS data-collection modes, the diagnostic programs to test the operating hardware, and the data format. Sample data printouts are also included

  19. Adaptive Genetic Algorithm Model for Intrusion Detection

    Directory of Open Access Journals (Sweden)

    K. S. Anil Kumar

    2012-09-01

    Full Text Available Intrusion detection systems are intelligent systems designed to identify and prevent the misuse of computer networks and systems. Various approaches to Intrusion Detection are currently being used, but they are relatively ineffective. Thus the emerging network security systems need be part of the life system and this ispossible only by embedding knowledge into the network. The Adaptive Genetic Algorithm Model - IDS comprising of K-Means clustering Algorithm, Genetic Algorithm and Neural Network techniques. Thetechnique is tested using multitude of background knowledge sets in DARPA network traffic datasets.

  20. Computationally Efficient Neural Network Intrusion Security Awareness

    Energy Technology Data Exchange (ETDEWEB)

    Todd Vollmer; Milos Manic

    2009-08-01

    An enhanced version of an algorithm to provide anomaly based intrusion detection alerts for cyber security state awareness is detailed. A unique aspect is the training of an error back-propagation neural network with intrusion detection rule features to provide a recognition basis. Network packet details are subsequently provided to the trained network to produce a classification. This leverages rule knowledge sets to produce classifications for anomaly based systems. Several test cases executed on ICMP protocol revealed a 60% identification rate of true positives. This rate matched the previous work, but 70% less memory was used and the run time was reduced to less than 1 second from 37 seconds.

  1. Distributed Firewall with Intrusion Detection System

    Directory of Open Access Journals (Sweden)

    Linquan Xie

    2012-12-01

    Full Text Available With the growth of Internet, network security has received significant attention over pass ten years due to the increasing threat of hacker attacks. To achieve security goals, most corporate environments have deployed firewalls to block the intrusion. However, traditional firewalls only provided static filleting analysis so that they can not analyze the content of data packet for providing dynamic security requirement. In order to address this issue, in this paper, we integrate the traditional firewalls with intrusion detection technologies. The proposed can provides dynamic security defense by atomically updating the policies based on the detection condition.

  2. Laboratory studies of radionuclide transport in fractured Climax granite

    International Nuclear Information System (INIS)

    This report documents our laboratory studies of radionuclide transport in fractured granite cores. To simulate natural conditions, our laboratory studies used naturally fractured cores and natural ground water from the Climax Granite Stock at the Nevada Test Site. For comparison, additional tests used artificially fractured granite cores or distilled water. Relative to the flow of tritiated water, 85Sr and /sup 95m/Tc showed little or no retardation, whereas 137Cs was retarded. After the transport runs the cores retained varying amounts of the injected radionuclides along the fracture. Autoradiography revealed some correlation between sorption and the fracture fill material. Strontium and cesium retention increased when the change was made from natural ground water to distilled water. Artificial fractures retained less 137Cs than most natural fractures. Estimated fracture apertures from 18 to 60 ?m and hydraulic conductivities from 1.7 to 26 x 10-3 m/s were calculated from the core measurements

  3. Association of lung cancer mortality with precambrian granite

    International Nuclear Information System (INIS)

    Sixteen counties in New York, Pennsylvania, and New Jersey that are associated with the Reading Prong granite deposits have significantly higher age-adjusted lung cancer rates among whites of both sexes (1950-1979) than do 17 nearby control counties. Elevated radon daughter concentrations have been found in homes near the Reading Prong granites. Fraction of populations living in cities with over 5,000 persons, industrial centers, cities with populations above 20,000, and median incomes did not differ significantly for three county groups (those which include the granite, fringe area, and control areas). Weaknesses were inadequate home measurements of radon and lack of smoking information. Findings are consistent with several other studies relating radon in homes to lung cancer

  4. Extraction of uranium and thorium and other metals from granite

    International Nuclear Information System (INIS)

    It is shown that within the igneous rocks the granites have the highest uranium and thorium contents. These elements are extractable from the rock by means of leaching or chlorination. The energy needed for the extraction is less than 10% of the energy obtainable by burning the uranium and thorium in breeder reactors. In order to increase the economy of the uranium and thorium extraction, other metals (Si, Al,..) are suggested to be extracted from the granite. The reserves of energy contained in the uranium and thorium of the granites make it possible to meet the needs of energy of a future world population of 8 to 12 billions requiring 15 kW per capita for thousands of years

  5. The Polumir granite: Addititional data on its origin

    Directory of Open Access Journals (Sweden)

    Vukov Milenko S.

    2002-01-01

    Full Text Available The Polumir granite is exposed on several localities due to erosion, and its chemical and mineral composition is presented in this paper. It is built of K-feldspar, plagioclase, myrmekite, metasomatic albite, biotite, muscovite and quartz, while apatite, magnetite, monazite, allanite and zircon are present as accessory minerals. According to its chemical and mineral composition and rock chemistry (trace and REE elements the Polumir granite is leucocratic, sin-collisional, with S-type characteristics. It crystallized at temperature of about 650°C and under pressure of 2-4 kbar. Results of isotope analyses (K-Ar method on biotites indicate that the Polumir granite was formed during the Miocene (14-19 Ma and it has undergone subsequent weak remobilization afterwards.

  6. Smolt Monitoring at the Head of Lower Granite Reservoir and Lower Granite Dam, 2002 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Buettner, Edwin W.; Putnam, Scott A. [Idaho Department of Fish and Game

    2009-02-18

    This project monitored the daily passage of Chinook salmon Oncorhynchus tshawytscha, steelhead trout O. mykiss, and sockeye salmon smolts O. nerka during the 2002 spring out-migration at migrant traps on the Snake River and Salmon River. In 2002 fish management agencies released significant numbers of hatchery Chinook salmon and steelhead trout above Lower Granite Dam that were not marked with a fin clip or coded-wire tag. Generally, these fish were distinguishable from wild fish by the occurrence of fin erosion. Total annual hatchery Chinook salmon catch at the Snake River trap was 11.4 times greater in 2002 than in 2001. The wild Chinook catch was 15.5 times greater than the previous year. Hatchery steelhead trout catch was 2.9 times greater than in 2001. Wild steelhead trout catch was 2.8 times greater than the previous year. The Snake River trap collected 3,996 age-0 Chinook salmon of unknown rearing. During 2002, the Snake River trap captured 69 hatchery and 235 wild/natural sockeye salmon and 114 hatchery coho salmon O. kisutch. Differences in trap catch between years are due to fluctuations not only in smolt production, but also differences in trap efficiency and duration of trap operation associated with flow. The significant increase in catch in 2002 was due to a 3.1 fold increase in hatchery Chinook production and a more normal spring runoff. Trap operations began on March 10 and were terminated on June 7. The trap was out of operation for a total of four days due to mechanical failure or debris. Hatchery Chinook salmon catch at the Salmon River trap was 4.2 times greater and wild Chinook salmon catch was 2.4 times greater than in 2001. The hatchery steelhead trout collection in 2002 was 81% of the 2001 numbers. Wild steelhead trout collection in 2002 was 81% of the previous year's catch. Trap operations began on March 10 and were terminated on May 29 due to high flows. The trap was out of operation for four days due to high flow or debris. The increase in hatchery Chinook catch in 2002 was due to a 3.1 fold increase in hatchery production and differences in flow between years. Changes in hatchery and wild steelhead catch are probably due to differences in flow between years. Travel time (d) and migration rate (km/d) through Lower Granite Reservoir for PIT-tagged Chinook salmon and steelhead trout marked at the Snake River trap were affected by discharge. Statistical analysis of 2002 data detected a relation between migration rate and discharge for hatchery and wild Chinook salmon. For hatchery and wild Chinook salmon there was a 4.7-fold and a 3.7-fold increase in migration rate, respectively, between 50 and 100 kcfs. For steelhead trout tagged at the Snake River trap, statistical analysis detected a significant relation between migration rate and Lower Granite Reservoir inflow discharge. For hatchery and wild steelhead trout, there was a 1.8-fold and a 1.7-fold increase in migration rate, respectively, between 50 and 100 kcfs. Travel time and migration rate to Lower Granite Dam for fish marked at the Salmon River trap were calculated. Statistical analysis of the 2002 data detected a significant relation between migration rate and Lower Granite Reservoir inflow discharge for wild Chinook salmon and hatchery steelhead trout. The analysis was unable to detect a relation between migration rate and discharge for hatchery Chinook salmon. The lack of a detectable relation was probably a result of the migration rate data being spread over a very narrow range of discharge. Not enough data were available to perform the analysis for wild steelhead trout. Migration rate increased 4.3-fold for wild Chinook salmon and 2.2-fold for hatchery steelhead between 50 kcfs and 100 kcfs. Fish tagged with passive integrated transponder (PIT) tags at the Snake River trap were interrogated at four dams with PIT tag detection systems (Lower Granite, Little Goose, Lower Monumental, and McNary dams). Because of the addition of the fourth interrogation site (Lower Monumental) in 1993 and the installation of the Removable Spillway Wei

  7. Smolt Monitoring at the Head of Lower Granite Reservoir and Lower Granite Dam, 2004 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Buettner, Edwin W.; Putnam, Scott A. [Idaho Department of Fish and Game

    2009-02-18

    This project monitored the daily passage of Chinook salmon Oncorhynchus tshawytscha, steelhead trout O. mykiss, and sockeye salmon O. nerka smolts during the 2004 spring out-migration at migrant traps on the Snake River and Salmon River. In 2004 fish management agencies released significant numbers of hatchery Chinook salmon and steelhead trout above Lower Granite Dam that were not marked with a fin clip or coded-wire tag. Generally, these fish were distinguishable from wild fish by the occurrence of fin erosion. Total annual hatchery Chinook salmon catch at the Snake River trap was 1.1 times greater in 2004 than in 2003. The wild Chinook catch was 1.1 times greater than the previous year. Hatchery steelhead trout catch was 1.2 times greater than in 2003. Wild steelhead trout catch was 1.6 times greater than the previous year. The Snake River trap collected 978 age-0 Chinook salmon of unknown rearing. During 2004, the Snake River trap captured 23 hatchery and 18 wild/natural sockeye salmon and 60 coho salmon O. kisutch of unknown rearing. Differences in trap catch between years are due to fluctuations not only in smolt production, but also differences in trap efficiency and duration of trap operation associated with flow. Trap operations began on March 7 and were terminated on June 4. The trap was out of operation for a total of zero days due to mechanical failure or debris. Hatchery Chinook salmon catch at the Salmon River trap was 10.8% less and wild Chinook salmon catch was 19.0% less than in 2003. The hatchery steelhead trout collection in 2004 was 20.0% less and wild steelhead trout collection was 22.3% less than the previous year. Trap operations began on March 7 and were terminated on May 28 due to high flows. There were two days when the trap was taken out of service because wild Chinook catch was very low, hatchery Chinook catch was very high, and the weekly quota of PIT tagged hatchery Chinook had been met. Travel time (d) and migration rate (km/d) through Lower Granite Reservoir for PIT-tagged Chinook salmon and steelhead trout marked at the Snake River trap were affected by discharge. Statistical analysis of 2004 data detected a relation between migration rate and discharge for wild Chinook salmon but was unable to detect a relation for hatchery Chinook. The inability to detect a migration rate discharge relation for hatchery Chinook salmon was caused by age-0 fall Chinook being mixed in with the age 1 Chinook. Age-0 fall Chinook migrate much slower than age-1 Chinook, which would confuse the ability to detect the migration rate discharge relation. When several groups, which consisted of significant numbers of age-0 Chinook salmon, were removed from the analysis a relation was detected. For hatchery and wild Chinook salmon there was a 2.8-fold and a 2.4-fold increase in migration rate, respectively, between 50 and 100 kcfs. For steelhead trout tagged at the Snake River trap, statistical analysis detected a significant relation between migration rate and Lower Granite Reservoir inflow discharge. For hatchery and wild steelhead trout, there was a 2.3-fold and a 2.0-fold increase in migration rate, respectively, between 50 and 100 kcfs. Travel time and migration rate to Lower Granite Dam for fish marked at the Salmon River trap were calculated. Statistical analysis of the 2004 data detected a significant relation between migration rate and Lower Granite Reservoir inflow discharge for hatchery Chinook salmon, wild Chinook salmon and hatchery steelhead trout. Not enough data were available to perform the analysis for wild steelhead trout. Migration rate increased 7.0-fold for hatchery Chinook salmon, 4.7-fold for wild Chinook salmon and 3.8-fold for hatchery steelhead as discharge increased between 50 kcfs and 100 kcfs. Fish tagged with passive integrated transponder (PIT) tags at the Snake River and Salmon River traps were interrogated at four dams with PIT tag detection systems (Lower Granite, Little Goose, Lower Monumental, and McNary dams). Because of the addition of the fourth interrogation site (Lower Monume

  8. Petrogenesis of synorogenic diorite-granodiorite-granite complexes in the Damara Belt, Namibia: Constraints from U-Pb zircon ages and Sr-Nd-Pb isotopes

    Science.gov (United States)

    Jung, S.; Kröner, A.; Hauff, F.; Masberg, P.

    2015-01-01

    The synorogenic Palmental complex (central Damara Belt, Nambia) consists of ca. 545 Ma old quartz diorites and rare granodiorites and ca. 520 Ma-old leucogranites, representing one of the earliest and most primitive phase of crustal plutonism predating the main high-T regional metamorphism. Most quartz diorites and one granodiorite evolved through multistage, polybaric evolutionary processes involving fractionation from a lithospheric mantle-derived melt, followed by fractional crystallization of mainly hornblende, plagioclase and apatite which is shown by decreasing MgO, FeO, CaO, TiO2 and P2O5 with increasing SiO2. Assimilation of felsic basement gneisses was also important during formation of these granitoids. Although their chemical characteristics (high LILE, low HFSE) resemble those of quartz diorites and granodiorites with calc-alkaline affinity, they differ in their enriched Sr (initial 87Sr/86Sr: 0.7061-0.7098) and Nd (initial ?Nd: -2.7 to -9.9) isotopic composition. Neodymium depleted mantle mean crustal residence ages range from 1.3 to 1.9 Ga for the quartz diorites including the granodiorite. These model ages correlate with major and trace element abundances, further substantiating that AFC processes modified the initial isotopic systematics. Lead (206Pb/204Pb: 17.43-17.68, 207Pb/204Pb: 15.61-15.66, 208Pb/204Pb: 38.19-38.49) isotopic composition are unradiogenic relative to other Damaran intrusive rocks but plot above the Stacey and Kramers (1975) reference line, indicating that the source underwent an ancient (pre Pan-African) increase in U/Pb and Th/U, followed by more recent U-depletion. Some variation in 206Pb/204Pb at high 207Pb/204Pb further indicates involvement of ancient crustal material, most likely through AFC processes. A cross-cutting leucogranite dyke has also evolved isotopic compositions (initial 87Sr/86Sr: 0.7326; initial ?Nd: -15.6; 206Pb/204Pb: 17.42, 207Pb/204Pb: 15.62, 208Pb/204Pb: 38.16) but in view of the apparent younger age of the granite, this rock type cannot be considered as a fractionation product of the quartz diorites and therefore represents likely a melting product of the underlying felsic basement. We also report data from two quartz diorite samples collected in the north and east of the Palmental area. They plot off the trends defined by the other quartz diorites. Palaeoproterozoic Nd model ages of 2.1 Ga and distinct Pb isotopic data indicate a Palaeoproterozoic mean crustal residence age for the source material. We conclude that these samples belong to the nearby Goas and Okongava quartz diorites. For these rocks, based on a previous model and a comparison with results from amphibolite-dehydration melting experiments, a high-K meta-tholeiite melted at 1000-1050 °C is a likely source. Isotopic data obtained on samples of the Palmental complex make a Pan African subduction zone setting unlikely for these rocks. It is concluded that the most primitive Palmental quartz diorites recording moderately evolved Nd and Sr isotope data (?Nd(t): -2.7, 87Sr/86Sr: 0.706) reflect an isotope composition typical of aged subcrustal lithospheric mantle.

  9. Design and Implementation of Intrusion Detection System (Ids) Sensor Deployment

    OpenAIRE

    Mr.Patil Mahesh A

    2014-01-01

    Network intrusion detection systems provide proactive defense against security threats by detecting and blocking attack-related traffic. This task can be highly complex, and therefore, software-based network intrusion detection systems have difficulty in handling high speed links. This paper describes the design and implementation of a high-performance network intrusion detection system that combines the use of software-based network intrusion detection sensors deployment. In ...

  10. Simulation of network intrusion detection system with GPenSim

    OpenAIRE

    Liu, Bo

    2011-01-01

    In recent years, network has penetrated into every aspect of our life with its rapid growth and popularization. More and more serious network security problems have occurred together with this process, especially network intrusion problem. It has seriously affected the normal use of network, so research of network intrusion detection has become one of the hottest research areas. This thesis simulated a network intrusion detection system based on particle filter to solve the network intrusion ...

  11. Effective analysis of cloud based intrusion detection system

    OpenAIRE

    Sanjay Ram

    2012-01-01

    The goal of IDS is to analyze events on the network and identify attacks. The increasing number of network security related incidents makes it necessary for organizations to actively protect their sensitive data with the installation of intrusion detection systems (IDS). People are paid more attention on intrusion detection which as an important computer network security technology. According to the development trend of intrusion detection, detecting all kinds of intrusions effectively requir...

  12. Various Approaches for Detecting Attacks in Intrusion Detection System

    OpenAIRE

    Prof. Priti Subramanium; Purva Adlakha

    2013-01-01

    The rapid development of computer networks and more importantly internet has created many security problems such as ever growing new intrusions on computer network systems. To secure this systemstrong intrusion detection system has to be build. An intrusion detection system monitors all inbound and outbound network activity and identifies suspicious activities that attempting to break and violate security of system. In this paper we have taken review of various approaches of Intrusion detecti...

  13. An Attribute-weighted Clustering Intrusion Detection Method

    OpenAIRE

    Lifang Wang; Shuhai Zhang; Yurong Li; Ruijuan Wu; Yi Yu

    2013-01-01

    Intrusion detection system is automatic system which recognize intrusions of computers or computer network systems. The existing security detection systems have many problems such as wrong detection of intrusions, false intrusions, poor real-time performance. To solve these problems, this paper improves the particle swarm optimization algorithm and presents an attribute-weighted distance calculation method based on information gain ratio. This method for the division of spherical or ellipsoid...

  14. Identification and Effects of Thin Vertical Intrusions on Seismic Data

    OpenAIRE

    Lødemel, Håvard

    2013-01-01

    In this report I consider a case with a simple three-dimensional two-layer model penetrated by a thin vertical intrusion. Synthetic seismic data is generated, and a number of events are identified. The identified events affected by the vertical intrusions are a prismatic wave, reflected from both the layer boundary and the intrusion wall, and two diffractions. The first diffraction event occurs where the intrusion penetrates the layer boundary (representing a vertical change in elastic parame...

  15. Territorial intrusion risk and antipredator behaviour: a mathematical model.

    OpenAIRE

    Di?az-uriarte, R.

    2001-01-01

    In territorial animals that hide to avoid predators, a predatory attack creates a conflict because a hiding animal cannot defend its territory from conspecific intruders. When intruders are persistent, a past conspecific intrusion informs a territorial resident that future intrusions by the same animal are likely. Using a mathematical model, I examine the effects that past territorial intrusions can have on antipredator behaviour. Past territorial intrusions rarely affect a resident animal's ...

  16. Microcracking and healing in granites: new evidence from cathodoluminescence.

    Science.gov (United States)

    Sprunt, E S; Nur, A

    1979-08-01

    Quartz grains in granitic rocks usually have blue cathodoluminescence (CL). Within the blue-luminescing grains, there are often red-luminescing domains which are frequently impossible to detect without CL contrast. This finding suggests that the red-luminescing quartz is sealing preexisting mnicrocracks. The presence of these now-healed microcracks has important implications with respect to the role of pore fluid pressure and fluid transfer in metamorphism, the origih of granites, longperiod crustal deformation, earthquake mechanics, physical properties of rocks, and deep-seated geothermal energy. PMID:17758791

  17. 76 FR 62758 - Wallowa-Whitman and Umatilla National Forests, Oregon Granite Creek Watershed Mining Plans

    Science.gov (United States)

    2011-10-11

    ...Forests, Oregon Granite Creek Watershed Mining Plans AGENCY: Forest Service, USDA. ACTION...impact statement to authorize the approval of mining Plans of Operation in the Granite Creek Watershed Mining Plans analysis area on the Whitman...

  18. New Data Mining Algorithm for Intrusion Detection in Networks?

    OpenAIRE

    Penchala Praveen, M.; Sambath, M.; Ravi?, S.

    2013-01-01

    An intrusion detection system is a mechanism that monitors network or system activities formalicious activities. Intrusion detection and prevention systems (IDPS) are primarily focused on identifyingpossible incidents, logging information about them and reporting attempts .In organizations use IDPS forother purposes, such as identifying problems with security policies and deterring individuals from violatingsecurity policies. Intrusion detection systems have become a necessary addition to the...

  19. Temporal Associations and Prior-List Intrusions in Free Recall

    Science.gov (United States)

    Zaromb, Franklin M.; Howard, Marc W.; Dolan, Emily D.; Sirotin, Yevgeniy B.; Tully, Michele; Wingfield, Arthur; Kahana, Michael J.

    2006-01-01

    When asked to recall the words from a just-presented target list, subjects occasionally recall words that were not on the list. These intrusions either appeared on earlier lists (prior-list intrusions, or PLIs) or had not appeared over the course of the experiment (extra-list intrusions). The authors examined the factors that elicit PLIs in free…

  20. Global magnetic cycles in rapidly rotating younger suns

    CERN Document Server

    Nelson, Nicholas J; Browning, Matthew K; Brun, Allan Sacha; Miesch, Mark S; Toomre, Juri

    2010-01-01

    Observations of sun-like stars rotating faster than our current sun tend to exhibit increased magnetic activity as well as magnetic cycles spanning multiple years. Using global simulations in spherical shells to study the coupling of large-scale convection, rotation, and magnetism in a younger sun, we have probed effects of rotation on stellar dynamos and the nature of magnetic cycles. Major 3-D MHD simulations carried out at three times the current solar rotation rate reveal hydromagnetic dynamo action that yields wreaths of strong toroidal magnetic field at low latitudes, often with opposite polarity in the two hemispheres. Our recent simulations have explored behavior in systems with considerably lower diffusivities, achieved with sub-grid scale models including a dynamic Smagorinsky treatment of unresolved turbulence. The lower diffusion promotes the generation of magnetic wreaths that undergo prominent temporal variations in field strength, exhibiting global magnetic cycles that involve polarity reversal...

  1. Mental health status among younger generation around Chernobyl

    Science.gov (United States)

    Masunaga, Tomoko; Kozlovsky, Alexander; Lyzikov, Anatoly; Yamashit, Shunichi

    2013-01-01

    Introduction In order to improve our understanding of how to approach the younger generation around Chernobyl, we screened mental health status among young adults born after the accident living in the Gomel region, Belarus. Material and methods We enrolled 697 medical students who were born after the accident. Participants were asked to answer self-administered questionnaires including the General Health Questionnaire (GHQ-12). Results GHQ-12 scores were 1.80 ±2.28 (mean ± SD) among all 697 subjects. When logistic regression analysis was performed with confounding factors, “economic situation” and “association of diseases and/or poor health condition with radiation exposure” were significantly associated with poor mental status. Conclusions Our findings suggest that anxiety about radiation exposure among highly educated medical students in the Gomel region, although they were born after the accident, affects their poor mental health status. PMID:24482659

  2. Habitual fat intake predicts memory function in younger women

    Directory of Open Access Journals (Sweden)

    Edward LeighGibson

    2013-12-01

    Full Text Available High intakes of fat have been linked to greater cognitive decline in old age, but such associations may already occur in younger adults. We tested memory and learning in 38 women (25-45 years old, recruited for a larger observational study in women with polycystic ovary syndrome. These women varied in health status, though not significantly between cases (n=23 and controls (n=15. Performance on tests sensitive to medial temporal lobe function (CANTABeclipse, Cambridge Cognition Ltd., i.e. verbal memory, visuo-spatial learning and delayed pattern matching, were compared with intakes of macronutrients from 7-day diet diaries and physiological indices of metabolic syndrome. Partial correlations were adjusted for age, activity and verbal IQ (National Adult Reading Test. Greater intakes of saturated and trans fats, and higher saturated to unsaturated fat ratio (Sat:UFA, were associated with more errors on the visuo-spatial task and with poorer word recall and recognition. Unexpectedly, higher UFA intake predicted poorer performance on the word recall and recognition measures. Fasting insulin was positively correlated with poorer word recognition only, whereas higher blood total cholesterol was associated only with visuo-spatial learning errors. None of these variables predicted performance on a delayed pattern matching test. The significant nutrient-cognition relationships were tested for mediation by total energy intake: saturated and trans fat intakes, and Sat:UFA, remained significant predictors specifically of visuo-spatial learning errors, whereas total fat and UFA intakes now predicted only poorer word recall. Examination of associations separately for mono- (MUFA and polyunsaturated fats suggested that only MUFA intake was predictive of poorer word recall. Saturated and trans fats, and fasting insulin, may already be associated with cognitive deficits in younger women. The findings need extending but may have important implications for public health.

  3. Geologic Mapping in Nogal Peak Quadrangle: Geochemistry, Intrusive Relations and Mineralization in the Sierra Blanca Igneous Complex, New Mexico

    Science.gov (United States)

    Goff, F.; Kelley, S. A.; Lawrence, J. R.; Cikowski, C. T.; Krier, D. J.; Goff, C. J.; McLemore, V. T.

    2011-12-01

    Nogal Peak quadrangle is located in the northern Sierra Blanca Igneous Complex (SBIC) and contains most of the White Mountain Wilderness (geologic map is available at http://geoinfo.nmt.edu/publications/maps/geologic/ofgm/details.cfml?Volume=134). The geology of the quad consists of a late Eocene to Oligocene volcanic pile (Sierra Blanca Volcanics, mostly alkali basalt to trachyte) intruded by a multitude of dikes, plugs and three stocks: Rialto, 31.4 Ma (mostly syenite), Three Rivers, ca. 29 to 27 Ma (quartz syenite intruded by subordinate alkali granite), and Bonito Lake, 26.6 Ma (mostly monzonite). Three Rivers stock is partially surrounded by alkali rhyolites that geochemically resemble the alkali granites. The circular shape of the stock and surrounding rhyolites suggests they form the root of a probable caldera. SBIC rocks have compositions typical of those found within the Rocky Mountain alkaline belt and those associated with continental rift zone magmatism. Because the volcanic host rocks are deeply eroded, intrusive relations with the stocks are well exposed. Most contacts at stock margins are near vertical. Roof pendants are common near some contacts and stoped blocks up to 700 m long are found within the Three Rivers stock. Contacts, pendants and stoped blocks generally display some combination of hornfelsing, brecciation, fracturing, faulting and mineralization. Sierra Blanca Volcanics display hydrothermal alteration increasing from argillic in the NW sector of the quad to high-temperature porpylitic near stock margins. Retrograde phyllic alteration occurs within breccia pipes and portions of the stocks. Mineral deposits consist of four types: Placer Au, fissure veins (mostly Ag-Pb-Zn±Au), breccia pipes (Au-Mo-Cu), and porphyry Mo-Cu. A singular pipe on the SW margin of Bonito Lake stock contains sapphire-lazulite-alunite. Although Au has been intermittently mined in the quad since 1865, best production of Au originated around the turn of the last century from the Parsons Mine, a breccia pipe in the southern Rialto stock. The Great Western Mine deposit, located within three breccia pipes on the north margin of Three Rivers stock, apparently contains 150,000 troy ounces of low-grade, disseminated Au. Three Rivers syenites and alkali granites are slightly enriched in REE compared to typical intrusive rock standards but are not high enough to be exploitable. One alkali granite sample contains 2850 ppm Zr, about 5 to 10 times the values of typical rock standards.

  4. Geochemistry of enclaves and host granites from the Nelas area, central Portugal

    OpenAIRE

    Silva, M. M. V. G.; Neiva, A. M. R.; Whitehouse, M. J.

    2000-01-01

    Tonalitic, granodioritic and monzogranitic enclaves occur in the Hercynian peraluminous porphyritic biotite granite and biotite-muscovite granite from the Nelas region. Some variation diagrams show linear trends, but others show dispersion. The enclaves generally have closely similar isotopic signatures to those of the host granites. They contain xenocrystic plagioclase with the same composition as phenocrysts of the host granite, and have biotite as the sole ferromagnesian phase with a compo...

  5. From granite to highly evolved pegmatite: A case study of the Pinilla de Fermoselle granite-pegmatite system (Zamora, Spain)

    Science.gov (United States)

    Roda-Robles, E.; Pesquera, A.; Gil-Crespo, P.; Torres-Ruiz, J.

    2012-11-01

    The Pinilla de Fermoselle pegmatite is a cap-like body with an asymmetrical vertical zoning, from a granitic facies at the bottom to the upper contact with the metamorphic country-rocks. The granite grades imperceptibly into the pegmatite, which includes three main zones with different degrees of enrichment in Li + F + B (± P, Rb, Cs, Be, Sn). The essential minerals are quartz, feldspar, Al-micas from the muscovite-lepidolite series, Fe-micas (biotite and zinnwaldite), tourmaline (schorl-elbaite-rossmanite) and Fe-Mn phosphates. Apatite, beryl, cassiterite and cookeite are the most significant accessory minerals. The trace elements Li, Be and Sr show similar trends in feldspar, micas and tourmaline, with an increase in the Li and Be contents and a decrease in Sr from the granite to the most evolved pegmatitic zone. Similar trends are shown by Rb, Cs and Ba for micas and K-feldspar, Rb and Cs increasing gradually from the granite to most evolved pegmatitic zones, simultaneously to the decrease of Ba. In tourmaline Nb and Ta contents increase upwards whereas Zn contents decrease in the same way. The Mn contents increase until intermediate degrees of evolution, and decrease again in the pinkish elbaite. Combined field, petrographic and geochemical data are consistent with a fractional crystallization model from a granitic melt, with a clear petrogenetic relationship between the underlying peraluminous granite and the pegmatite body. K-feldspar and, particularly, micas and tourmaline appear as good geochemical monitors using trace elements such as Li, Rb, Be, Sr and Ba, which offer intriguing insights into the petrogenesis of pegmatites.

  6. Smart sensor systems for outdoor intrusion detection

    International Nuclear Information System (INIS)

    A major improvement in outdoor perimeter security system probability of detection (PD) and reduction in false alarm rate (FAR) and nuisance alarm rate (NAR) may be obtained by analyzing the indications immediately preceding an event which might be interpreted as an intrusion. Existing systems go into alarm after crossing a threshold. Very slow changes, which accumulate until the threshold is reached, may be assessed falsely as an intrusion. A hierarchial program has begun at Stellar to develop a modular, expandable Smart Sensor system which may be interfaced to most types of sensor and alarm reporting systems. A major upgrade to the SSI Test Site is in progress so that intrusions may be simulated in a controlled and repeatable manner. A test platform is being constructed which will operate in conduction with a mobile instrumentation center with CCTVB, lighting control, weather and data monitoring and remote control of the test platform and intrusion simulators. Additional testing was contracted with an independent test facility to assess the effects of severe winter weather conditions

  7. An Adaptive Database Intrusion Detection System

    Science.gov (United States)

    Barrios, Rita M.

    2011-01-01

    Intrusion detection is difficult to accomplish when attempting to employ current methodologies when considering the database and the authorized entity. It is a common understanding that current methodologies focus on the network architecture rather than the database, which is not an adequate solution when considering the insider threat. Recent…

  8. Towards better tamper&intrusion detection

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, R. G. (Roger G.); Garcia, A. R. E. (Anthony R. E.); Pacheco, A. N. (Adam N.)

    2002-01-01

    This presentation discusses in generic terms some of the work of the Vulnerability Assessment Team at Los Alamos National Laboratory in the area of tamper and intrusion detection. Novel security approaches are discussed. We also present preliminary results for a crude prototype of a high security ('Town Crier') monitoring system for securing moving cargo or stationary assets.

  9. Evolutionary Design of Intrusion Detection Programs

    Directory of Open Access Journals (Sweden)

    Ajith Abraham

    2007-05-01

    Full Text Available Intrusion detection is the process of monitoring the events occurring in a computer system or network and analyzing them for signs of intrusions, defined as attempts to compromise the confidentiality, integrity, availability, or to bypass the security mechanisms of a computer or network. This paper proposes the development of an Intrusion Detection Program (IDP which could detect known attack patterns. An IDP does not eliminate the use of any preventive mechanism but it works as the last defensive mechanism in securing the system. Three variants of genetic programming techniques namely Linear Genetic Programming (LGP, Multi-Expression Programming (MEP and Gene Expression Programming (GEP were evaluated to design IDP. Several indices are used for comparisons and a detailed analysis of MEP technique is provided. Empirical results reveal that genetic programming technique could play a major role in develop- ing IDP, which are light weight and accurate when compared to some of the conventional intrusion detection systems based on machine learning paradigms.

  10. How stratospheric are deep stratospheric intrusions?

    Science.gov (United States)

    Trickl, T.; Vogelmann, H.; Giehl, H.; Scheel, H.-E.; Sprenger, M.; Stohl, A.

    2014-09-01

    Preliminary attempts of quantifying the stratospheric ozone contribution in the observations at the Zugspitze summit (2962 m a.s.l.) next to Garmisch-Partenkirchen in the German Alps had yielded an approximate doubling of the stratospheric fraction of the Zugspitze ozone during the time period 1978 to 2004. These investigations had been based on data filtering by using low relative humidity (RH) and elevated 7Be as the criteria for selecting half-hour intervals of ozone data representative of stratospheric intrusion air. To quantify the residual stratospheric component in stratospherically influenced air masses, however, the mixing of tropospheric air into the stratospheric intrusion layers must be taken into account. In fact, the dewpoint mirror instrument at the Zugspitze summit station rarely registers RH values lower than 10% in stratospheric air intrusions. Since 2007 a programme of routine lidar sounding of ozone, water vapour and aerosol has been conducted in the Garmisch-Partenkirchen area. The lidar results demonstrate that the intrusion layers are drier by roughly one order of magnitude than indicated in the in situ measurements. Even in thin layers RH values clearly below 1% have frequently been observed. These thin, undiluted layers present an important challenge for atmospheric modelling. Although the ozone values never reach values typical of the lower-stratosphere it becomes, thus, obvious that, without strong wind shear or convective processes, mixing of stratospheric and tropospheric air must be very slow in most of the free troposphere. As a consequence, the analysis the Zugspitze data can be assumed to be more reliable than anticipated. Finally, the concentrations of Zugspitze carbon monoxide rarely drop inside intrusion layers and normally stay clearly above full stratospheric values. This indicates that most of the CO, and thus the intrusion air mass, originates in the shallow "mixing layer" around the thermal tropopause. The CO mixing ratio in these descending layers between 1990 and 2004 exhibits a slightly positive trend indicating some Asian influence on the lowermost stratosphere in the high-latitude source region of most intrusions reaching the station.

  11. How stratospheric are deep stratospheric intrusions?

    Directory of Open Access Journals (Sweden)

    T. Trickl

    2014-06-01

    Full Text Available Preliminary attempts of quantifying the stratospheric ozone contribution in the observations at the Zugspitze summit (2962 m a.s.l. next to Garmisch-Partenkirchen in the German Alps had yielded an approximate doubling of the stratospheric fraction of the Zugspitze ozone during the time period 1978 and 2004. These investigations had been based on data filtering by using low relative humidity and elevated 7Be as the criteria for selecting half-hour intervals of ozone data representative of stratospheric intrusion air. For quantifying the residual stratospheric component in stratospherically influenced air masses, however, the mixing of tropospheric air into the stratospheric intrusion layers must be taken into account. In fact, the dew-point-mirror instrument at the Zugspitze summit station rarely registers relative humidity (RH values lower than 10% in stratospheric air intrusions. Since 2007 a programme of routine lidar sounding of ozone, water vapour and aerosol has been conducted in the Garmisch-Partenkirchen area. The lidar results demonstrate that the intrusion layers are dryer by roughly one order of magnitude than indicated in the in-situ measurements. Even in thin layers frequently RH values clearly below 1% have been observed. These thin, undiluted layers present an important challenge for atmospheric modelling. Although the ozone values never reach values typical of the lower-stratosphere it becomes, thus, obvious that, without strong wind shear or convective processes, mixing of stratospheric and tropospheric air must be very slow in most of the free troposphere. As a consequence, the analysis the Zugspitze data can be assumed to be more reliable than anticipated. Finally, the concentrations of Zugspitze carbon monoxide rarely drop inside intrusion layers and normally stay clearly above full stratospheric values. This indicates that most of the CO and, thus, the intrusion air mass originate in the shallow "mixing layer" around the thermal tropopause. The CO mixing ratio in these descending layers between 1990 and 2004 exhibits a slightly positive trend indicating some Asian influence on the lowermost stratosphere in the high-latitude source region of most intrusions reaching the station.

  12. How stratospheric are deep stratospheric intrusions?

    Directory of Open Access Journals (Sweden)

    T. Trickl

    2014-09-01

    Full Text Available Preliminary attempts of quantifying the stratospheric ozone contribution in the observations at the Zugspitze summit (2962 m a.s.l. next to Garmisch-Partenkirchen in the German Alps had yielded an approximate doubling of the stratospheric fraction of the Zugspitze ozone during the time period 1978 to 2004. These investigations had been based on data filtering by using low relative humidity (RH and elevated 7Be as the criteria for selecting half-hour intervals of ozone data representative of stratospheric intrusion air. To quantify the residual stratospheric component in stratospherically influenced air masses, however, the mixing of tropospheric air into the stratospheric intrusion layers must be taken into account. In fact, the dewpoint mirror instrument at the Zugspitze summit station rarely registers RH values lower than 10% in stratospheric air intrusions. Since 2007 a programme of routine lidar sounding of ozone, water vapour and aerosol has been conducted in the Garmisch-Partenkirchen area. The lidar results demonstrate that the intrusion layers are drier by roughly one order of magnitude than indicated in the in situ measurements. Even in thin layers RH values clearly below 1% have frequently been observed. These thin, undiluted layers present an important challenge for atmospheric modelling. Although the ozone values never reach values typical of the lower-stratosphere it becomes, thus, obvious that, without strong wind shear or convective processes, mixing of stratospheric and tropospheric air must be very slow in most of the free troposphere. As a consequence, the analysis the Zugspitze data can be assumed to be more reliable than anticipated. Finally, the concentrations of Zugspitze carbon monoxide rarely drop inside intrusion layers and normally stay clearly above full stratospheric values. This indicates that most of the CO, and thus the intrusion air mass, originates in the shallow "mixing layer" around the thermal tropopause. The CO mixing ratio in these descending layers between 1990 and 2004 exhibits a slightly positive trend indicating some Asian influence on the lowermost stratosphere in the high-latitude source region of most intrusions reaching the station.

  13. Smolt Monitoring at the Head of Lower Granite Reservoir and Lower Granite Dam, 2003 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Buettner, Edwin W.; Putnam, Scott A. [Idaho Department of Fish and Game

    2009-02-18

    This project monitored the daily passage of Chinook salmon Oncorhynchus tshawytscha, steelhead trout O. mykiss, and sockeye salmon O. nerka smolts during the 2003 spring out-migration at migrant traps on the Snake River and Salmon River. In 2003 fish management agencies released significant numbers of hatchery Chinook salmon and steelhead trout above Lower Granite Dam that were not marked with a fin clip or coded-wire tag. Generally, these fish were distinguishable from wild fish by the occurrence of fin erosion. Total annual hatchery Chinook salmon catch at the Snake River trap was 2.1 times less in 2003 than in 2002. The wild Chinook catch was 1.1 times less than the previous year. Hatchery steelhead trout catch was 1.7 times less than in 2002. Wild steelhead trout catch was 2.1 times less than the previous year. The Snake River trap collected 579 age-0 Chinook salmon of unknown rearing. During 2003, the Snake River trap captured five hatchery and 13 wild/natural sockeye salmon and 36 coho salmon O. kisutch of unknown rearing. Differences in trap catch between years are due to fluctuations not only in smolt production, but also differences in trap efficiency and duration of trap operation associated with flow. The significant differences in catch between 2003 and the previous year were due mainly to low flows during much of the trapping season and then very high flows at the end of the season, which terminated the trapping season 12 days earlier than in 2002. Trap operations began on March 9 and were terminated on May 27. The trap was out of operation for a total of zero days due to mechanical failure or debris. Hatchery Chinook salmon catch at the Salmon River trap was 16.8% less and wild Chinook salmon catch was 1.7 times greater than in 2002. The hatchery steelhead trout collection in 2003 was 5.6% less than in 2002. Wild steelhead trout collection was 19.2% less than the previous year. Trap operations began on March 9 and were terminated on May 24 due to high flows. There were zero days when the trap was out of operation due to high flow or debris. The decrease in hatchery Chinook catch in 2003 was partially due to differences in flow between years because there was a 5.9% increase in hatchery production in the Salmon River drainage in 2003. The decrease in hatchery steelhead catch may be partially due to a 13% decrease in hatchery production in the Salmon River drainage in 2003. Travel time (d) and migration rate (km/d) through Lower Granite Reservoir for PIT-tagged Chinook salmon and steelhead trout marked at the Snake River trap were affected by discharge. Statistical analysis of 2003 data detected a relation between migration rate and discharge for wild Chinook salmon but was unable to detect a relation for hatchery Chinook. The inability to detect a migration rate discharge relation for hatchery Chinook was probably caused by age 0 fall Chinook being mixed in with the age 1 Chinook. Age 0 fall Chinook migrate much slower than age 1 Chinook, which would confuse the ability to detect the migration rate discharge relation. For wild Chinook salmon there was a 1.4-fold increase in migration rate, respectively, between 50 and 100 kcfs. For steelhead trout tagged at the Snake River trap, statistical analysis detected a significant relation between migration rate and Lower Granite Reservoir inflow discharge. For hatchery and wild steelhead trout, there was a 1.7-fold and a 1.9-fold increase in migration rate, respectively, between 50 and 100 kcfs. Travel time and migration rate to Lower Granite Dam for fish marked at the Salmon River trap were calculated. Statistical analysis of the 2003 data detected a significant relation between migration rate and Lower Granite Reservoir inflow discharge for hatchery Chinook salmon, wild Chinook salmon and hatchery steelhead trout. Not enough data were available to perform the analysis for wild steelhead trout. Migration rate increased 14-fold for hatchery Chinook salmon, 8.3-fold for wild Chinook salmon and 2.4-fold for hatchery steelhead as discharge increased between 50 kcfs and

  14. Geochemistry of granulite-facies granitic rocks from Battye Glacier, northern Prince Charles Mountains, East Antarctica

    International Nuclear Information System (INIS)

    Proterozoic basement outcrops in the vicinity of Battye Glacier, northern Prince Charles Mountains, are dominated by granulites and gneisses derived from felsic (granitoid) intrusive igneous rocks, and by pegmatites. Felsic orthopyroxene granulites, garnet leucogneisses and garnet pegmatites have major and trace element compositions of highly felsic, but not strongly fractionated, granites. The garnet leucogneisses and garnet pegmatites have S-type characteristics, whereas the felsic granulites are probably I-type, although their high Zr+Nb+Y+Ce abundances suggest possible A-type affinities. Intermediate orthopyroxene ± clinopyroxene granulites mostly resemble I-type quartz diorites, except for a small subgroup of samples (characterised by low Na2O and K2O, and high MgO, Ni, Cr and HREE) of uncertain affinities and significance. Element ratios involving LILE (e.g. K/Rb, Rb/Ba, Rb/Sr, K/La, La/Th) closely match those typical of the inferred granitoid protoliths, suggesting that these rocks have experienced relatively little LILE depletion (except possibly for U) during regional metamorphism. It is therefore inferred that metamorphism was probably broadly isochemical. Because the felsic and intermediate granulites and garnet leucogneisses are Sr-depleted, Y-undepleted and mostly have negative Eu anomalies they are inferred to be the products of partial melting of felsic crustal sources leaving plagioclase-bearing residua. Plagioclase fractionationearing residua. Plagioclase fractionation during crystallisation could also account for these characteristics, but K/Rb, Rb/Ba and Rb/Sr ratios in these rocks are not consistent with strong fractionation of feldspar. Garnet pegmatites differ chemically from garnet leucogneisses mainly in their lower Fe, Ti, Nb, Zn, Zr, Th and REE abundances and positive Eu anomalies, related to lower garnet, ilmenite and zircon contents in the garnet pegmatites. A genetic link between these two rock types, probably involving fractionation of these minerals during partial melting or crystallisation, is inferred. Incompatible-element abundances suggest that generation of the Battye Glacier granitic magmas from felsic crust might have occurred in a mature continental magmatic arc possibly well removed from an active subduction trench or, perhaps, in an intracontinental setting

  15. Intrusion Detection in Data Mining With Classification Algorithm

    OpenAIRE

    Patel Hemant, Bharat Sarkhedi

    2013-01-01

    In the research of intrusion detection there are so manyattacks in the real life and some IDS System to detect it like network-based IDS, host-based IDS and application-based IDS to detect the Intrusion. In this paper, one frame work is introduce to detect an intrusion data with the help of data mining, a framework for intrusion detection system for filtering data set to network attacks. We also talk about the basic data mining technology for finding intrusion data for the data set. Detection...

  16. The state of the art in intrusion prevention and detection

    CERN Document Server

    Pathan, Al-Sakib Khan

    2013-01-01

    The State of the Art in Intrusion Prevention and Detection analyzes the latest trends and issues surrounding intrusion detection systems in computer networks, especially in communications networks. Its broad scope of coverage includes wired, wireless, and mobile networks; next-generation converged networks; and intrusion in social networks.Presenting cutting-edge research, the book presents novel schemes for intrusion detection and prevention. It discusses tracing back mobile attackers, secure routing with intrusion prevention, anomaly detection, and AI-based techniques. It also includes infor

  17. Extraction of Th and U from Swiss granites

    International Nuclear Information System (INIS)

    The extraction, at the laboratory level, of U and Th from Swiss granites is discussed. The Mittagfluh, Bergell and Rotondo granites and the Giuv syenite offered a wide range of U and Th concentrations; 7.7 to 20.0 ppm U and 25.5 to 67.0 ppm Th. U and Th were determined in the leach solutions by the fission track method and by spectrophotometry, respectively. Samples containing less than 0.3 ?g U and 4 ?g Th, could be measured with an accuracy of 10% for U and 5% for Th. Leach tests were performed during which the following parameters were varied: granite-type, grain size, acid-type, acid concentration, temperature and time. There were very great leaching differences between the granites studied. Temperature was the most important parameter. Sharp differences in extraction occurred between 200C, 500C and 800C. At 800C, more than 85% U and Th were extracted. The extraction curve (percent extracted as a function of time) of aliquots sampled after 1, 2, 4, 8, 12 and 24 hours showed a plateau after 8 hours. The half life of the reaction was between one and two hours. As a general rule, Th was better extracted than U. (Auth.)

  18. Chemical Variations in a Granitic Pluton and Its Surrounding Rocks.

    Science.gov (United States)

    Baird, A K; McIntyre, D B; Welday, E E; Madlem, K W

    1964-10-01

    New techniques of x-ray fluorescence spectrography have provided, for the first time, abundant data regarding chemical variability of granitic rocks on different scales. The results suggest that current designs of sampling plans for trend surface analysis should be modified; in particular several specimens, preferably drillcores, may be required at each locality. PMID:17743708

  19. Vein uranium deposits in granites of Xiazhuang ore field

    International Nuclear Information System (INIS)

    The Xianzhuang ore field is one of the important uranium districts of China from which substantial uranium resources are known. It lies within the Caledonian orogenic belt, where during the Yenshanian tectonic phase intensive tectono-magmatic activities took place. All uranium ore deposits of this district belong to the vein-type uranium deposits being mainly characterized by a pitchblende-microquartz assemblage closely associated with an argillitization-pyritization alteration of the host rock. These deposits are located in a down-faulted block within the Guidong granite massif, which is characterized by a quite perfect granitic differentiation together with an intensive autometamorphism. The granite contains higher uranium and uraninite values. The age of the rock-forming period is 185 to 135 Ma, but the ore-forming period is 85 to 70 Ma. Thus the source of uranium must have been the consolidated granite itself. Fluid inclusion data and stable isotope information show that the ore formation took place mainly between 280 to 150 deg. C under abruptly decreasing pressure conditions and significant escaping of gases. (author)

  20. Vývoj dvojslídných granit? subtypu ?ím?? v centrálním moldanubickém plutonu.

    Czech Academy of Sciences Publication Activity Database

    Mat?jka, D.; Nosek, T.; René, Miloš

    2002-01-01

    Ro?. 10, - (2002), s. 214-247. ISSN 1211-0329 R&D Projects: GA MŠk ME 459 Institutional research plan: CEZ:AV0Z3046908 Keywords : two-mica granite * Moldanubian batholith * Bohemian Massif Subject RIV: DB - Geology ; Mineralogy

  1. Rb-Sr ages and palaeomagnetic data for some Angolan alkaline intrusives

    International Nuclear Information System (INIS)

    New Rb-Sr age measurements are reported for a number of intrusives from Angola. Data for the Njoio and Tchivira nepheline syenite bodies yield mineral isochrons indicating ages of 104,3+-0,8 Ma and 130,8+-1,4 Ma respectively. Palaeomagnetic studies on the same occurrences gave marginal and scattered results respectively. Micas from the Camafuca crater-facies kimberlite yielded and apparent age of 1 822+-151 Ma, a result that is far in excess of the Tertiary (or younger) age inferred for this pipe. Similarly conflicting data were obtained for the Nova Lisboa kimberlite. It is likely that older crustal micas incorporated in the kimberlite breccias are responsible for the anomalous ages reported on the kimberlites. Satisfactory palaeomagnetic data are reported for the Zenza and Bailundu occurrences, not dated by the Rb-Sr method. A convenient K-Ar age of 80+-0,8 Ma was obtainable for Zenza

  2. Gravity and magnetic modeling of granitic bodies in Central Portugal

    Science.gov (United States)

    Machadinho, Ana; Figueiredo, Fernando; Pereira, Alcides

    2015-04-01

    A better understanding of the subsurface geometry of the granitic bodies in Central Portugal is the main goal of this work. The results are also relevant for the assessment of the geothermal potential of the same region. The study area is located in the Central Iberian Zone where the Beiras granite batholith outcrops. These variscan granitoids were emplaced into the "Complexo Xisto-Grauváquico" (CXG), a thick and monotonous megasequences of metapelites and metagreywackes. This metasedimentary sequence is affected by the Variscan deformation phases and a late Proterozoic to Cambrian age has been generally assumed for this rocks. The granitoids in the region are attributed to the magmatic activity associated to the post-collisional stages of the Variscan orogeny during the D3 stage. The granitic bodies in the study area are considered syn-D3 and late to post-D3. To achieve the goal of the research, magnetic and gravimetric surveys where performed in order to obtain the Bouguer and magnetic anomalies. All the standard corrections were applied to the gravimetric and magnetic data. Considering and integrating all the available geological data and physical proprieties (density and magnetic susceptibility) the mentioned potential fields were simultaneously modeled. In this way it was possible to characterize the subsurface geometry of the granitic bodies in the studied region. The modeling results show that the regional tectonic setting controls the geometry of the granitic bodies as well as the structure of the host CXG metasedimentary sequence. Through the modeling of the potential field the overall geometry, average and maximum depths of the granitic bodies in the study area was obtained. Some late to post-D3 plutons outcrop in spatial continuity and as they have similar ages, a common feeding zone is assumed as the most likely scenario. The sin-D3 pluton is more abrupt and vertical, suggesting the presence of a fault contact with the late-D3 pluton. According to the developed study the areas with higher geothermal potential for EGS applications are located over the sectors where the granitic bodies have the greater thickness.

  3. Etude de la diagraphie neutron du granite de Beauvoir. Effet neutron des altérations et de la matrice du granite. Calibration granite. Porosité totale à l'eau et porosité neutron Analysis of the Beauvoir Granite Neutron Log. Neutron Effect of Alterations and of the Granite Matrix. Granite Calibration. Total Water Porosity and Neutron Porosity

    OpenAIRE

    Galle C.; Lapeyre C.; Struillou R.

    2006-01-01

    Cet article rend compte des travaux effectués sur la porosité du granite de Beauvoir (Sondage GPF 1 d'Echassières, Massif Central français). L'objectif de notre étude est de pouvoir obtenir des valeurs représentatives de la saturation en eau (porosité totale à l'eau n) du granite de Beauvoir à partir des mesures de porosité neutron PorositéN (diagraphie neutron BRGM) sans avoir recours aux mesures sur carottes. Notre démarche est expérimentale et nous avons tenté d'approfondir c...

  4. Intrusion Detection in Data Mining With Classification Algorithm

    Directory of Open Access Journals (Sweden)

    PATEL HEMANT, BHARAT SARKHEDI, HIREN VAGHAMSHI

    2013-07-01

    Full Text Available In the research of intrusion detection there are so manyattacks in the real life and some IDS System to detect it like network-based IDS, host-based IDS and application-based IDS to detect the Intrusion. In this paper, one frame work is introduce to detect an intrusion data with the help of data mining, a framework for intrusion detection system for filtering data set to network attacks. We also talk about the basic data mining technology for finding intrusion data for the data set. Detection in the field of data mining for intrusion detection. We also discuss some of the common algorithms for intrusion detection, such as decision trees, Naive Bayes, Naive Bayes (CFSGSW, NBTree improved adaptive NBTree it.

  5. Proliferation and demise of deep-sea corals in the Mediterranean during the Younger Dryas

    Energy Technology Data Exchange (ETDEWEB)

    McCulloch, Malcolm [ARC Centre of Excellence for Coral Reef Studies, School of Earth and Environment, The University of Western Australian, Crawley, 6009, Western Australia (Australia); Research School of Earth Sciences, Australian National University, Canberra, 0200 (Australia); Taviani, Marco; Lopez Correa, Matthias; Remia, Alessandro [ISMAR-CNR, via Gobetti 101, I-40129 Bologna (Italy); Montagna, Paolo [LSCE, Av. de la Terrasse, 91198 Gif-sur-Yvette, France, ISMAR-CNR, via Gobetti 101, I-40129 Bologna (Italy); Mortimer, Graham [Research School of Earth Sciences, Australian National University, Canberra, 0200 (Australia)

    2010-07-01

    Uranium-series and radiocarbon ages are reported for deep-sea corals Madrepora oculata, Desmophyllum dianthus, Lophelia pertusa and Caryophyllia smithii from the Mediterranean Sea. U-series dating indicates that deep-sea corals have persisted in the Mediterranean for over 480, 000 years, especially during cool inter-stadial periods. The most prolific period of growth however appears to have occurred within the Younger Dryas (YD) period from 12, 900 to 11, 700 years BP followed by a short ({approx} 330 years) phase of post-YD coral growth from 11, 230 to 10, 900 years BP. This indicates that deep-sea corals were prolific in the Mediterranean not only during the return to the more glacial-like conditions of the YD, but also following the rapid deglaciation and transition to warmer conditions that followed the end of the YD. Surprisingly, there is a paucity Last Glacial Maximum (LGM) coral ages, implying they were largely absent during this period when cold-water conditions were more prevalent. Radiocarbon ages show that the intermediate depth waters of the Mediterranean generally had {Delta}{sup 14}C compositions similar to surface waters, indicating that these waters were extremely well ventilated. The only exception is a narrow period in the YD (12, 500 {+-} 100 years BP) when several samples of Lophelia pertusa from the Ionian Sea had {Delta}{sup 14}C values falling significantly below the marine curve. Using a refined approach, isolation ages (T{sub isol}) of 300 years to 500 years are estimated for these intermediate (800-1000 m) depth waters relative to surface marine waters, indicating a reduction or absence of deep-water formation in the Ionian and adjacent Adriatic Seas during the YD. Contrary to previous findings, we find no evidence for widespread intrusion of low {Delta}{sup 14}C Atlantic waters into the Mediterranean. Prolific growth of deep-sea corals in the Mediterranean ended abruptly at {approx} 10, 900 years BP, with many of the coral-bearing mounds on the continental slopes being draped in a thin veneer of mud. Their demise is attributed to a number of factors, including the direct loss of habitat due to high sedimentation that accompanied glacial meltwater pulses, together with rising temperatures that would have finally pervaded the deeper water of the Mediterranean following the onset of Holocene warming. (authors)

  6. Proliferation and demise of deep-sea corals in the Mediterranean during the Younger Dryas

    International Nuclear Information System (INIS)

    Uranium-series and radiocarbon ages are reported for deep-sea corals Madrepora oculata, Desmophyllum dianthus, Lophelia pertusa and Caryophyllia smithii from the Mediterranean Sea. U-series dating indicates that deep-sea corals have persisted in the Mediterranean for over 480, 000 years, especially during cool inter-stadial periods. The most prolific period of growth however appears to have occurred within the Younger Dryas (YD) period from 12, 900 to 11, 700 years BP followed by a short (? 330 years) phase of post-YD coral growth from 11, 230 to 10, 900 years BP. This indicates that deep-sea corals were prolific in the Mediterranean not only during the return to the more glacial-like conditions of the YD, but also following the rapid deglaciation and transition to warmer conditions that followed the end of the YD. Surprisingly, there is a paucity Last Glacial Maximum (LGM) coral ages, implying they were largely absent during this period when cold-water conditions were more prevalent. Radiocarbon ages show that the intermediate depth waters of the Mediterranean generally had ?14C compositions similar to surface waters, indicating that these waters were extremely well ventilated. The only exception is a narrow period in the YD (12, 500 ± 100 years BP) when several samples of Lophelia pertusa from the Ionian Sea had ?14C values falling significantly below the marine curve. Using a refined approach, isolation ages (Tisol) of 300 yearn ages (Tisol) of 300 years to 500 years are estimated for these intermediate (800-1000 m) depth waters relative to surface marine waters, indicating a reduction or absence of deep-water formation in the Ionian and adjacent Adriatic Seas during the YD. Contrary to previous findings, we find no evidence for widespread intrusion of low ?14C Atlantic waters into the Mediterranean. Prolific growth of deep-sea corals in the Mediterranean ended abruptly at ? 10, 900 years BP, with many of the coral-bearing mounds on the continental slopes being draped in a thin veneer of mud. Their demise is attributed to a number of factors, including the direct loss of habitat due to high sedimentation that accompanied glacial meltwater pulses, together with rising temperatures that would have finally pervaded the deeper water of the Mediterranean following the onset of Holocene warming. (authors)

  7. Contamination in mafic mineral-rich calc-alkaline granites: a geochemical and Sr-Nd isotope study of the Neoproterozoic Piedade Granite, SE Brazil

    OpenAIRE

    Renato J. Leite; Valdecir A. Janasi; Lucelene Martins

    2006-01-01

    The Piedade Granite (~600 Ma) was emplaced shortly after the main phase of granite magmatism in the Agudos Grandes batholith, Apiaí-Guaxupé Terrane, SE Brazil. Its main units are: mafic mineral-rich porphyritic granites forming the border (peraluminous muscovite-biotite granodiorite-monzogranite MBmg unit) and core (metaluminous titanite-bearing biotite monzogranite BmgT unit) and felsic pink inequigranular granite (Bmg unit) between them. Bmg has high LaN/YbN (up to 100), Th/U (>10) and low ...

  8. Post-collisional multistage magmatism in the Ribeira mobile belt: geochemical and isotopic study of the Varzea Alegre intrusive complex, Espirito Santo, Brazil

    International Nuclear Information System (INIS)

    The Varzea Alegre Intrusive Complex (VAIC) corresponds to a post-collisional (late orogenic) pluton, related to the Brasiliano cycle, situated in the central part of the Espirito Santo State. It intrudes amphibolite to granulite facies metamorphic rocks of the Ribeira Belt. Two distinct domains were recognised in this zoned pluton: an inner domain with opx-gabbro, monzogabbro, diorite, quartz-diorite and megaporphyritic granite, and an outer one comprising an irregular and large ring of charnockitic rocks. Geochemical data from the former reveal medium to high-K calc-alkalic rocks, enriched in incompatible elements, mainly Ba, Sr, La, Ce and Pb and partially depleted in HFS elements. The charnockitic rocks show a high-K alkali-calcic signature; they are rich in Ba, K and some HFS elements, such a Zr, P and Nb. The incompatible element enrichment detected in the rocks of the VAIC has been reported for several intrusions from this part of the Ribeira Belt. A Rb-Sr isochronic age of 508± 12 Ma was determined for the megaporphyritic granite. The TDM model age varies from 1.3 Ga (opx-gabbro) to ca. 1.67 Ga (charnockitic rocks), which can be related to an important Mesoproterozoic crustal event. The calculated TCHUR model ages of the cogenetic opx-gabbros and intermediary rocks is ca. 1.0 Ga, interpreted as the time when the basic magma was extracted from the source. (author)

  9. Geochemistry, geochronology, and origin of the Neoarchean Planalto Granite suite, Carajás, Amazonian craton: A-type or hydrated charnockitic granites?

    Science.gov (United States)

    Feio, G. R. L.; Dall'Agnol, R.; Dantas, E. L.; Macambira, M. J. B.; Gomes, A. C. B.; Sardinha, A. S.; Oliveira, D. C.; Santos, R. D.; Santos, P. A.

    2012-10-01

    New whole-rock geochemistry and LA-MC-ICPMS and Pb-evaporation geochronological data were obtained on zircon from the Neoarchean Planalto suite granites and associated charnockitic rocks of the Canaã area of the Carajás province, eastern Amazonian craton, Brazil. The Pb-evaporation ages of three samples from the Planalto suite are around 2730 Ma (2733 ± 2 Ma, 2731 ± 1 Ma and 2736 ± 4 Ma), whereas U-Pb LA-MC-ICPMS concordia ages obtained for these samples are 2729 ± 17 Ma, 2710 ± 10 Ma, and 2706 ± 5 Ma, respectively. An orthopyroxene quartz gabbro associated with the Pium complex and Planalto suite yielded a U-Pb concordia age of 2735 ± 5 Ma, interpreted as its crystallization age. The Planalto suite granites and the charnockitic rocks associated with the Mesoarchean Pium complex were probably crystallized at 2730 ± 10 Ma. The Planalto granites have ferroan character and are similar geochemically to reduced A-type granites. In previous studies, they have been classified as such, despite the fact that they are syntectonic. The tectonic setting and the association between the Planalto suite and charnockitic series led us to classify these biotite-hornblende granites as hydrated granites of the charnockitic series. The Planalto suite and the Neoarchean charnockitic magmas were more probably derived by partial melting of mafic to intermediate tholeiitic orthopyroxene-bearing rocks similar to those of the Pium complex. At 2.76 Ga, upwelling of asthenospheric mantle in an extensional setting propitiated the formation of the Carajás basin. Later on, at ca. 2.73 Ga, heat input associated with underplate of mafic magma induced partial melting of mafic to intermediate lower crustal rocks, originating the Planalto and charnockitic magmas. The emplacement of these magmas occurred under active regional stress and resultant major shear zones found in the Canaã dos Carajás area. The close association between the Planalto suite and charnockitic rocks suggests that they are similar to the high temperature granite magmatism found near the borders of Precambrian domains with different ages and tectonic evolution or in their zone of interaction.

  10. Global magnetic cycles in rapidly rotating younger suns

    Science.gov (United States)

    Nelson, Nicholas J.; Brown, Benjamin P.; Browning, Matthew K.; Brun, Allan Sacha; Miesch, Mark S.; Toomre, Juri

    2011-08-01

    Observations of sun-like stars rotating faster than our current sun tend to exhibit increased magnetic activity as well as magnetic cycles spanning multiple years. Using global simulations in spherical shells to study the coupling of large-scale convection, rotation, and magnetism in a younger sun, we have probed effects of rotation on stellar dynamos and the nature of magnetic cycles. Major 3-D MHD simulations carried out at three times the current solar rotation rate reveal hydromagnetic dynamo action that yields wreaths of strong toroidal magnetic field at low latitudes, often with opposite polarity in the two hemispheres. Our recent simulations have explored behavior in systems with considerably lower diffusivities, achieved with sub-grid scale models including a dynamic Smagorinsky treatment of unresolved turbulence. The lower diffusion promotes the generation of magnetic wreaths that undergo prominent temporal variations in field strength, exhibiting global magnetic cycles that involve polarity reversals. In our least diffusive simulation, we find that magnetic buoyancy coupled with advection by convective giant cells can lead to the rise of coherent loops of magnetic field toward the top of the simulated domain.

  11. Paleoproductivity during the Younger Dryas off northeastern Luzon, Philippines

    Science.gov (United States)

    Quevedo, J. M. D.; Siringan, F. P.; Villanoy, C.

    2014-12-01

    The influence of the Younger Dryas (YD) event on primary production off the northeast shelf of Luzon, Philippines is examined using sediment cores from two deep sea sites north of the Bicol shelf and with varying relative influence from terrestrial sediment input and the Kuroshio Current. Core A is immediately west of the Kuroshio feeder current and is off the slope while Core B is from a bathymetric high located almost west of Core A. XRF-, CHN- and LOI-derived geochemical proxies are utilized for reconstruction. A decrease in sediment input from ~12.9 to ~11.6 kyr BP corresponding to the YD event is indicated by the proxies, Ti, Al, and Al/Ti, in both cores. This is consistent with the drier climate during this period. Primary productivity indicators in the cores show opposing trends during the YD; Core A shows an increasing trend while Core B shows a decreasing trend. The decreasing trend in Core B can be due to a decrease in terrestrial nutrient input due to a decrease in precipitation. On the other hand, the increasing trend in Core A can be due to a swifter Kuroshio Current caused by a swifter and more southerly NEC bifurcation which in turn is due to a southerly shift of the ITCZ during YD. A swifter Kuroshio would have enhanced upwelling induced by steeper sea surface across the current and by more intense cyclonic gyres due to flow separation where the shelf width suddenly decreases north of the Bicol Shelf.

  12. Heinrich I and Younger Dryas Glaciation in the Central Andes

    Science.gov (United States)

    Zech, J.; Zech, R.; May, J.; Kubik, P. W.; Veit, H.

    2009-12-01

    Short term climate reversals, such as Heinrich I (H-I) and the Younger Dryas (YD), are well documented in the Northern Hemisphere. However, the respective response of the climate system in the Southern Hemisphere during these events remains enigmatic. Here we present 10Be surface exposure ages from the Wara Wara Valley (17°S, 66°W), Cordillera Cochabamba, that reveal glacial advances in the Central Andes before 14.3 ka and 11.9 ka. These advances correlate with H-I and YD and coincide with the lake transgression phases Tauca (18-14 ka) and Coipasa (13-11 ka) on the Altiplano. They corroborate the precipitation sensitivity of glacier mass balances in the semi-arid Central Andes. We suggest that sufficient moisture for glacial advances can be explained by enhanced upper tropospheric easterlies as a response to an intensified tropical circulation and sustained la Niña like patterns in the eastern Pacific. This redistribution of the ocean and atmospheric circulation was caused by a southward shift of the ITCZ due to northern hemispheric cooling. At 10.8 ka glacier advanced again attributed to increased moisture supply by enhanced polar advection and SE trade winds during the Early Holocene. Final deglaciation started only at 9.2 ka induced by a change to drier conditions.

  13. Petrochemistry and Geotectonic Setting of Granitic Rocks in Aderan Area, S.W. Nigeria

    Directory of Open Access Journals (Sweden)

    C. T. Okonkwo

    2012-12-01

    Full Text Available Aderan area, southwestern Nigeria is underlain by metaigneous and metasedimentary rocks which have been intruded by granitic rocks of probable Pan-African (ca. 600 Ma age. Four types of granitic rocks have been identified in the area, including granitic gneisses, medium-grained granite, porphyritic granite and granodiorite. Geochemical analysis show that the rocks are largely calc-alkaline. The granodiorite is less siliceous and more calcic, and also contains less Ba, Nb and Rb, and more Sr, Ce and La than the granites. Tectonically, the rocks classify as volcanic arc and syn-collisional and possibly late-to- post-collisional granitic rocks with respect to the Pan-African orogeny. Chemical characteristics indicate that these rocks were derived from partial melting of mafic to semi-pelitic (metasedimentary crustal rocks under conditions of intermediate oxygen fugacity and activities of H2O.

  14. The impact of a volcanic edifice on intrusive and eruptive activity

    Science.gov (United States)

    Roman, Alberto; Jaupart, Claude

    2014-12-01

    In a volcanic area, the orientation and composition of dikes record the development of the magmatic system that feeds intrusive and eruptive activity. At Spanish Peaks, Colorado, curved dike trajectories issuing from a single focal area have been attributed to horizontal propagation from a pressurized central reservoir in a deviatoric tectonic stress field. These dikes, however, are nowhere in contact with the central intrusion, are younger than it by about 1 My and are not filled with the same magma. They were emplaced at shallow depths (? 1 km), where the local stress field is very sensitive to surface loads. Here, we show that their trajectories can be set by the load of a volcanic edifice in a tectonic stress field. The orientation and distribution of the Spanish Peaks dikes have changed in the course of two million years as magmas were evolving chemically. Early dikes that were parallel to each another and filled with primitive melts document ascent in the regional tectonic stress field. They were replaced by curved dikes carrying evolved melts, which record the influence of a sizable volcanic edifice. Beneath this edifice, the induced compression prevented dense primitive magmas from erupting in the focal area and diverted intermediate magmas sideways. The growth of this large volcanic cone was probably responsible for the formation of a magma reservoir. The mechanisms that have shaped the Spanish Peaks dike swarm may control the spatial distribution and migration of eruptive centers in many active volcanic areas.

  15. The origin of halide melt phases in layered intrusions, and their significance to platinum-group element mobility

    Science.gov (United States)

    Hanley, J. J.

    2007-12-01

    Fluid and melt inclusions are preserved within pegmatite bodies and cumulus minerals within mafic-ultramafic layered intrusions that host economic concentrations of the platinum-group elements (e.g., Bushveld Complex, South Africa; Stillwater Complex, Montana). The inclusions indicate that the earliest volatile phase to have exsolved from the crystallizing intrusions was a relatively anhydrous carbonic fluid (CO2-dominated). As crystallization proceeded, volatiles became increasingly water-rich and saline, consistent with the relative saturation limits of carbonic and aqueous fluids in mafic silicate liquids, and the partitioning behavior of Cl in fluid-melt systems. Previously unreported, the latest stage volatiles in the layered intrusions were halide melts (slightly hydrous molten salts) of relatively simply composition (NaCl with minor KCl or CaCl2) with salinities in excess of 90 wt% eq. NaCl or CaCl2. These volatiles were trapped at minimum temperatures of 760-800°C, near the eutectic temperature for water-saturated granitic liquid at moderate crustal pressures. Trace element analysis of the salt melt inclusions by laser ablation ICP-MS (ETH Zürich) show that they contain no detectable concentrations of ore and accessory metals. This is in contrast to the earlier, lower salinity volatiles which contain ppm-concentrations of Pt, Pd, As, Bi, Sb as well as abundant S and base metals. Heterogeneous entrapment of late-stage silicate melt and halide melt provides unambiguous evidence for the coexistence of both phases. However, experimental constraints on the nature of exsolved volatiles from mafic or felsic silicate liquids suggest that the halide melt phases cannot represent an exsolved phase from that coexisting silicate liquid, since this would require unrealistically high (initial) Cl:H2O ratios for the parental silicate liquid (> 9 for a granitic residue). Analysis of rhyodacitic silicate melt inclusions that coexist with the halide melt inclusions show that the coeval silicate melts had Cl:H2O ratios of only 0.1 to 0.2. Similarily, the salt melt phases could not have evolved via the removal of H2O by crystallization of hydrous magmatic minerals (e.g., biotite, apatite) since their modal abundances in the intrusions are very low. The most plausible explanation for the halide melt phases involves the "dehydration" of an initially lower- salinity aqueous fluid. This may have occurred by the reaction of the aqueous fluid with nominally-anhydrous minerals such as pyroxene, or by the late-stage alteration of cumulus minerals to hydrous mineral assemblages. Through the use of conventional hydrothermal experimental techniques, it can be shown that the reaction of a volumetrically-minor CaCl2-rich aqueous fluid phase (20 wt% eq. CaCl2) with the assemblage diopside-enstatite-quartz at near-solidus conditions (700°C, 0.4 kbar) results in the formation of tremolite by the reaction of H2O with the initially anhydrous mafic mineral assemblage. The resulting salinity of the dehydrated saline phase, trapped as synthetic inclusions in quartz, was > 96 wt% eq. CaCl2, consistent with the water-poor nature of the salt melt inclusions from the intrusions. The results of this study indicate that, through the loss of H2O, metal-bearing aqueous volatiles in layered intrusions may precipitate metals as they are dehydrated to form salt melt phases. Metal precipitation may occur as amount of free H2O in the volatile phase necessary to hydrate metal complexes decreases. This precipitation mechanism challenges the conventional magmatic hypothesis for platinum-group element deposit formation in layered intrusions.

  16. Drilling the Bushveld Complex- the world's largest layered mafic intrusion

    Science.gov (United States)

    Ashwal, L. D.; Webb, S. J.; Trumbull, R. B.

    2013-12-01

    The fact that surprising new discoveries can be made in layered mafic intrusions (e.g., subtle 100-150 m cyclicity in apparently homogeneous cumulates over 1000s of m) means that we are still in the first-order characterization phase of understanding these objects. Accordingly, we have secured funding from ICDP for a planning workshop to be held in Johannesburg in early 2014, aimed at scientific drilling of the Bushveld Complex, the world's largest layered mafic intrusion. Science objectives include, but are not limited to: 1. Magma chamber processes & melt evolution. How many melts/magmas/mushes were involved, what were their compositions and how did they interact? What, if anything, is missing from the Complex, and where did it go? Did Bushveld magmatism have an effect upon Earth's atmosphere at 2 Ga? 2. Crust-mantle interactions & origin of Bushveld granitoids. Are Bushveld granites & rhyolites crustal melts, differentiates from the mafic magmas or products of immiscibility? How can the evolved isotopic signatures in the mafic rocks (e.g., epsilon Nd to -8) be understood? 3. Origin of ore deposits. What were the relative roles of gravity settling, magma mixing, immiscibility and hydrothermal fluid transport in producing the PGE, Cr and V deposits? We have identified 3 potential drilling targets representing a total of ~12 km of drill core. Exact locations of drill sites are to be discussed at the workshop. Target A- East-Central Bushveld Complex. We propose 3 overlapping 3 km boreholes that will provide the first roof-to-floor continuous coverage of the Rustenburg Layered Suite. These boreholes will represent a curated, internationally available reference collection of Bushveld material for present and future research. Target B- Southeastern Bushveld Complex. We propose a single borehole of ~2 km depth, collared in Rooiberg felsite, and positioned to intersect the Roof Zone, Upper Zone, Main Zone and floor of the Complex. Amongst other things, this site will evaluate the latest differentiates of the Complex: are they represented by felsic Rooiberg lavas (Van Tongeren & Mathez, 2012 J. Petrol. 51, 1891), or a newly-discovered sequence of hornblende quartz monzonites (Cawthorn, 2013, J. Petrol., in press)? Target C- Northern Lobe of Bushveld Complex. We propose 2 shorter ~500 m boreholes sited to (a) fill in missing stratigraphy of 2 existing deep cores (Bellevue & Moordkopje) including the unique 200 m thick troctolitic horizon in the Main Zone, and (b) to study the transgressive Main Zone - Upper Zone boundary several km north of the Bellevue/Moordkopje sites. All boreholes are intended to provide continuous down-hole geophysical measurements including magnetic susceptibility, density, electrical conductivity and radiometric data. There is also potential to obtain deep fluids and gases for biogeochemical and other studies. All interested geoscientists are welcome to attend the workshop. Watch the ICDP website for announcements (www.icdp-online.org).

  17. Quantitative assessment of radionuclide retention in the Quaternary sediments/granite interface of the Fennoscandian shield (Sweden)

    International Nuclear Information System (INIS)

    Highlights: ? The release of radionuclides from a deep geological repository is investigated. ? We simulate the transport of radionuclides in a Quaternary sediment. ? The Quaternary sediment's geochemistry is studied to select the reactive minerals. ? U, Sr, Cs and Ra were selected due to their contribution for the radioactive dose. ? The retention capacity of the Quaternary sediments was quantitatively evaluated. - Abstract: The Quaternary sediments representing the interface between the granite host rock and the Earth surface are of paramount importance when determining the potential cycling of anthropogenic and natural radionuclides in near-surface systems. This is particularly true in the case of high-level nuclear waste (HLNW) repositories placed in granite. In this work a modelling procedure is presented to quantitatively determine the retention capacity of a Quaternary till in the Forsmark area, which has been recently selected to host the deep geologic storage of HLNW in Sweden. Reactive transport numerical models have been used to simulate the intrusion of a deep groundwater carrying radionuclides potentially released from a repository into a Quaternary till. Four radionuclides (235U, 135Cs, 226Ra and 90Sr) have been selected according to their different geochemical behaviour and potential dose relevance to surface ecosystems. Numerical results indicate that repository-derived: (i) U will have a minor impaed: (i) U will have a minor impact in the till, mainly due to the high natural concentration of U and its adsorption on ferrihydrite; (ii) Cs will be efficiently retained by cation exchange on illite; (iii) Ra will be retained via co-precipitation with barite; and although (iv) Sr will be retained via co-precipitation with calcite and cation exchange on illite, the retention capacity of the Quaternary till for Sr is limited.

  18. Radon release from granites in south-west England

    International Nuclear Information System (INIS)

    The radon release from granitic samples from different sites in Cornwall was examined in an attempt to model the emanation mechanisms. Large samples were taken and cut into cuboid shapes of readily determinable surface area in order to measure the 222Rn flux. The flux from the granite samples shows that the high radon levels observed in houses in Cornwall cannot be attributable to building material alone and demonstrates the importance of large scale radon transport for the elevated levels in living quarters. Crushed chips of various sizes were also taken from selected sites (Carnsew quarry and Castle-an-Dinas quarry) to investigate the effect of specific surface area on radon release. It was found that radon release per gram increased as particle size decreased and declined again at small particle sizes. The samples were characterised in terms of physical properties, chemical composition and mineralogy. The radon release trend for the Carnsew samples was mirrored in the uranium and associated element concentrations. This was, however, not the case for the Castle-an-Dinas samples, and insufficient to explain the trend for both sets of samples. A model is proposed, based on spherical particles and uniform uranium distribution, to relate the radon release to specific surface area. The modelled specific surface areas for the chips was too low by 2-3 orders of magnitude as measured by gas adsorption techniques, and the uranium was concentrated in small accessoruranium was concentrated in small accessory minerals. The enhancement of surface area was attributed to the alteration of feldspar to sericite. This has implications for the release of radon. It is thought that the large surface area provides a sink for the adsorption of radon, retaining it in the rock structure. This radon retention explains the paradoxical decline in radon release at small particle size/large specific surface area. Various mechanisms for radon emanation are discussed with reference to the Cornubian granites. It is shown that, based on the measured specific surface areas, inter-crystalline diffusion is a slow process and not a significant contributor to overall radon release (0.01%). Approximately 1% of the total radon produced can be attributed to direct recoil processes, based on the calculated recoil ranges (36 nm). The remainder was attributed to diffusion processes through crystal imperfections and dislocations. The microscopic scale model developed here is extended to the macroscopic scale through examination of the large-scale factors that affect radon release. The effect of fractures and faults on macroscopic surface area and radon transport are discussed and it is concluded that their presence will increase radon release. Large-scale uranium distribution is discussed with respect to regional mineralisation. It is proposed that radon levels will be elevated in the vicinity of uraniferous mineral veins. The effect of soil covering on radon release is discussed. Whilst the soil layer inhibits radon release it is also possible that given the right formation conditions, a layer of soil may enhance radon release relative to the underlying rock source. These factors are drawn together to produce a general conceptual model for large-scale radon release. The conceptual model is applied to the granites of Cornwall (Carnmenellis pluton) through the investigation of the properties of the granite. Specifically, it is determined that the fractures in the Carnmenellis granite body will increase the radon release relative to an exposed plane surface. The various soils present on the Carnmenellis granite will serve to reduce the overall radon release, though the different types of soil have different permeabilites which lead to a variable radon release pattern across the pluton. The mineralisation will also cause the radon release to be variable across the granite body. Using the conceptual model, a radon release profile is proposed for a section across the Carnmenellis granite. The model is tested by comparison with other published data and fits well with th

  19. Zarzalejo granite (Spain). A nomination for 'Global Heritage Stone Resource'

    Science.gov (United States)

    Freire Lista, David Martin; Fort, Rafael; José Varas-Muriel, María

    2015-04-01

    Zarzalejo granite is quarried in the Sierra de Guadarrama (Spanish Central System) foothills, in and around Zarzalejo village, in the province of Madrid, Spain. It is an inequigranular monzogranite medium-to-coarse grained, with a slight porphyritic texture (feldspar phenocrysts) and mafic micro-grained enclaves. In this abstract the candidacy of Zarzalejo granite as a "Global Heritage Resource Stone" (GHSR) is presented. This stone ideally fits the newly proposed designation as it has been used in many heritage buildings and its good petrophysical properties and durability have allowed well preserved constructions such as a Roman road, San Pedro Church in Zarzalejo (1492), Descalzas Reales Monastery in Madrid (1559-1564) and the San Lorenzo del Escorial Royal Monastery (1563-1584), to be declared a World Heritage Site by UNESCO. This level of construction has been a landmark in the extraction and proliferation of historic quarries created due to the high demand that such colossal monuments and buildings with granite, have required for their construction. In the mid-20th century, More, Zarzalejo granite has also been used in restoration works including the Royal Palace and the Reina Sofía Museum (2001-2005), both buildings in Madrid, Spain. Extraction of granite ashlars from tors has been a very frequent activity in the Zarzalejo neighbourhood until mid-twentieth century. So there is also a need to preserve these historic quarries. This type of stone has created a landscape that has been preserved as an open-air museum today where you can see the marks left in the granite due to historic quarry operations. The granite industry has been one of the main pillars of the Zarzalejo regional economy. For centuries, the local community have been engaged in quarrying and have created a cultural landscape based on its building stone. A quarryman monument has been erected in Zarzalejo in honor of this traditional craft as well as an architecture museum at San Lorenzo del Escorial Monastery, which shows the building material used during its construction. There is currently an active quarry of this dimension stone which continues to be sold under the commercial name of "Gris Escorial". Zarzalejo granite is mainly exported to Turkey, Italy and Saudi Arabia. Today this stone is used primarily in flooring. Other uses include cobblestones, funeral art, and building and monument restoration and rehabilitation. Sculptures have also built in recent years, notably the great monoliths in Salvador Dalí Square (1989) in Madrid. There are also small historic family-run quarries intermittently continuing this dimension stone carving tradition. Given its characteristics, Zarzalejo granite meets the requisites proposed to be nominated as a GHSR. This nomination will contribute to raising awareness and disseminate key aspects for conservation and thus ensure its use as a replacement stone in restoring heritage buildings where it was used as a building stone. Acknowledgements This study was funded by the Community of Madrid under the GEOMATERIALS 2 project (S2013/MIT-2914). The authors are members of the Complutense University of Madrid's Research Group: "Alteración y Conservación de los Materiales Pétreos del Patrimonio" (ref. 921349).

  20. Petrochemistry of the Reduced, Ilmenite-Series Granitoid Intrusion Related to the Hired Gold-Tin Prospect (Basiran, Eastern Iran

    Directory of Open Access Journals (Sweden)

    M.H. Karimpour

    2009-01-01

    Full Text Available Doing research, two suites of Oligocene-Miocene granitoids, one relatively oxidized (magnetite-series and the other relatively reduced (ilmenite-series, were identified at Hired, Eastern Iran. Since Au-Sn mineralization is associated only with the relatively reduced ilmenite-series suite. It became interested to study the petrochemistry and petrophysics of these intrusive rocks. The magnetic susceptibility of the magnetite-series granitoids is greater than 300 x10-5 SI. This suite includes meta-aluminous, medium-K to high-K series gabbros to diorites containing magnetite, hornblende and biotite. The magnetic susceptibility of the ilmenite-series granitoids are less than 60 x10-5 SI. This suite includes meta-aluminous, high-K to shoshonitic diorites to granites, containing, biotite, muscovite and tourmaline. Both the ilmenite and magnetite series suites are strongly enriched in large ion lithophile elements (LILEs = K, Th, Rb, Ba and depleted in high field strength elements (HFSE = Nb, Sr, Ti, Hf. Chondrite-normalized Rare Earth Element (REE plots indicate strong enrichments of light relative to heavy REE, with (La/YbN between 7-24. Ilmenite suite granitoids have pronounced negative europium anomalies. Stockwork mineralization is found within and nearby the relatively reduced ilmenite-series granites. Based on their mineral assemblages (arsenopyrite, pyrrhotite, tourmaline, pyrite, gold and quartz, the ore-bearing fluids that generated these stockwork veins was also reduced. This and the spatial relationship of mineralization with the ilmenite suite granitoids, indicates that the ore fluids originated from reduced granitoid magmas. Hired Au-Sn deposit is a reduced-intrusion related gold system.

  1. A simplified approach to true molar intrusion

    Directory of Open Access Journals (Sweden)

    Flieger Stefanie

    2012-11-01

    Full Text Available Abstract Background Orthodontic management of anterior open bites is a demanding task for orthodontists. Molar intrusion as a primary means of open bite correction entails the need for appropriate anchorage. Orthodontic mini implants can provide the required mechanical support. The suggested procedure aims to reduce the risk of complications such as root damage or soft tissue irritations while minimizing overall complexity. Methods Three female patients aged 14, 18 and 19 years who decided against a surgical correction were treated with a device consisting of mini implants in the palatal slope, a palatal bar and intrusion cantilevers. Results In all three patients, an open bite reduction of more than a millimeter occurred within four months. An anterior overbite of 2 mm or more could be established within 6 to 9 months. Conclusions The method presented in this article enables the practitioner to use mini implants in an easily accessible insertion site. A lab-side procedure is optional but not required.

  2. Revealing Method for the Intrusion Detection System

    CERN Document Server

    Burney, S M Aqil

    2010-01-01

    The goal of an Intrusion Detection is inadequate to detect errors and unusual activity on a network or on the hosts belonging to a local network by monitoring network activity. Algorithms for building detection models are broadly classified into two categories, Misuse Detection and Anomaly Detection. The proposed approach should be taken into account, as the security system violations caused by both incompliance with the security policy and attacks on the system resulting in the need to describe models. However, it is based on unified mathematical formalism which is provided for subsequent merger of the models. The above formalism in this paper presents a state machine describing the behavior of a system subject. The set of intrusion description models is used by the evaluation module and determines the likelihood of undesired actions the system is capable of detecting. The number of attacks which are not described by models determining the completeness of detection by the IDS linked to the ability of detecti...

  3. Sensing Danger: Innate Immunology for Intrusion Detection

    CERN Document Server

    Uwe, Aickelin

    2008-01-01

    The immune system provides an ideal metaphor for anomaly detection in general and computer security in particular. Based on this idea, artificial immune systems have been used for a number of years for intrusion detection, unfortunately so far with little success. However, these previous systems were largely based on immunological theory from the 1970s and 1980s and over the last decade our understanding of immunological processes has vastly improved. In this paper we present two new immune inspired algorithms based on the latest immunological discoveries, such as the behaviour of Dendritic Cells. The resultant algorithms are applied to real world intrusion problems and show encouraging results. Overall, we believe there is a bright future for these next generation artificial immune algorithms.

  4. A Review on Network Intrusion Detection System

    Directory of Open Access Journals (Sweden)

    Preeti Yadav , Divakar Singh

    2013-09-01

    Full Text Available Internet and computer networks are exposed to an increasing number of security threats. For new types of attacks are emerging constantly, developing flexibility and adaptability safety-oriented approaches is a serious problem. In this context, the anomal based network Intrusion detection techniques are valuable technology to protect the target systems and networks against malicious activities. However, despite a number of these methods described in the literature in recent years, security tools comprising detecting anomalies function is only beginning to emerge, and several important issues remain to be solved. This paper begins with the review of the best-known anomaly-based intrusion detection techniques. Then the available platforms, systems development and research projects are presented. Finally, the main issues are addressed for large deployments, anomaly based detectors disruption, with special emphasis on the evaluation questions.

  5. Using Jquery with Snort to Visualize Intrusion

    Directory of Open Access Journals (Sweden)

    Alaa El - Din Riad

    2012-01-01

    Full Text Available The explosive growth of malicious activities on worldwide communication networks, such as the Internet, has highlighted the need for efficient intrusion detection systems. The efficiency of traditional intrusion detection systems is limited by their inability to effectively relay relevant information due to their lack of interactive / immersive technologies. Visualized information is a technique that can encode large amounts of complex interrelated data, being at the same time easily quantified, manipulated, and processed by a human user. Authors have found that the representations can be quite effective at conveying the needed information and resolving the relationships extremely rapidly. To facilitate the creation of novel visualizations this paper presents a new framework that is designed with using data visualization technique by using Jquery Php for analysis and visualizes snort result data for user.

  6. A Microcontroller Based Intrusion Detection System

    Directory of Open Access Journals (Sweden)

    Ewunonu Toochi

    2014-11-01

    Full Text Available A Microcontroller based Intrusion Detection System is designed and implemented. Rampant, Okintrusion to restricted zones have highlighted the need for embedded systems that can effectively monitor, instantly alert personnel of any breach in security and retrieve graphic evidence of any such activity in the secured area. At the heart of the intrusion detection system is the PIC 168F77A Microcontroller that transmits pulses at 38 KHz. It is suitably interfaced to a GSM modem that can send SMS on sight of infringement and a webcam that can take snapshots. The report also presents the system software which has been developed in two parts: one in C++ Language using MPLAB KIT and the other written in AT COMMAND resident in the GSM modem. The system is very cost-effective, uses easily available components and is adaptable to control systems.

  7. Etude de la diagraphie neutron du granite de Beauvoir. Effet neutron des altérations et de la matrice du granite. Calibration granite. Porosité totale à l'eau et porosité neutron Analysis of the Beauvoir Granite Neutron Log. Neutron Effect of Alterations and of the Granite Matrix. Granite Calibration. Total Water Porosity and Neutron Porosity

    Directory of Open Access Journals (Sweden)

    Galle C.

    2006-11-01

    Full Text Available Cet article rend compte des travaux effectués sur la porosité du granite de Beauvoir (Sondage GPF 1 d'Echassières, Massif Central français. L'objectif de notre étude est de pouvoir obtenir des valeurs représentatives de la saturation en eau (porosité totale à l'eau n du granite de Beauvoir à partir des mesures de porosité neutron PorositéN (diagraphie neutron BRGM sans avoir recours aux mesures sur carottes. Notre démarche est expérimentale et nous avons tenté d'approfondir certains problèmes liés à l'utilisation de la diagraphie neutron dans une roche granitique. Deux facteurs principaux conditionnent la réponse neutron : la concentration en hydrogène de la formation (eau libre et eau de constitution de certains minéraux et la présence d'éléments absorbeurs à forte section de capture comme le gadolinium, le cadmium, le bore, . . . et dans le cas du granite de Beauvoir, le lithium. A partir des mesures de porosité totale à l'eau n sur carottes, des essais de pertes au feu sur poudre qui nous permettent de déterminer la porosité neutron liée à l'eau de constitution PorositéN(OH- et des analyses chimiques avec lesquelles nous évaluons la porosité neutron thermique PorositéN(ox (Programme SNUPAR, Schlumberger liée à la capture neutronique, nous reconstituons la porosité neutron totale PorositéNR du granite de Beauvoir. Pour 7 échantillons caractéristiques du granite de Beauvoir, nous réalisons grâce à ces résultats une nouvelle calibration du taux de comptage neutron initial corrigé du gradient thermique et de l'effet de trou. Grâce à cette opération, il est possible de déterminer, pour les échantillons traités, la porosité neutron du granite avec une calibration granite (PorositéNg et non calcaire (PorositéNc. La connaissance de l'effet neutron de la matrice nous permet enfin d'évaluer la teneur en eau du granite (porosité totale à l'eau et de comparer celle-ci avec la porosité mesurée sur carottes (n. Nous montrons que, pour le granite de Beauvoir, l'effet neutron de la matrice est important (en moyenne proche de 7% et ne peut être négligé lorsque l'on mesure des porosités voisines de 0,5% sur carottes. La calibration de l'outil neutron dans le granite et non pas dans des calcaires est d'autre part capitale quant à la précision quantitative des résultats. This article describes the research done on the Beauvoir granite (Echassières GPF 1 borehole, French Massif Central range. The aim of this project was to obtain representative values of the water saturation (n total free water porosity of the Beauvoir granite from PorosityN neutron porosity (BRGM neutron log. The exact knowledge of the porosity of a crystalline block is effectively fundamental to determine its possibilities for being used as a waste storage site. With this goal, neutron logging provides indispensable information concerning the characterization of a porous medium. Our procedure was experimental, and we tried to go more deeply into various problems linked to the use of neutron logging in a granitic rock. Two main factors governed the neutron response : (i the hydrogen concentration of the formation (free water and combined water of various minerals and (ii the presence of absorber elements with a large capture cross-section such as gadolinium, cadmium, boron as well as lithium for the Beauvoir granite. After measuring the Beauvoir granite n total (free water porosity on core samples, we evaluated the combined water content of each sample tested on the basis of fire loss tests on rock powder at 900°C. From the hydrogen atoms volumic concentration, we determined a hydrogen index that we directly converted into the PorosityN(OH- neutron porosity, (by definition, pure water at 20°C has a hydrogen index of 1 which is equivalent to a 100% porosity. For the Beauvoir granite, the matrix combined water represents an average neutron porosity (Table 1 of about 4%. In the second phase, we used chemical analysis to evaluate the PorosityN(ox thermal neutron porosity linked to neutro

  8. Efficient Mining and Detection of Sequential Intrusion Patterns for Network Intrusion Detection Systems

    Science.gov (United States)

    Shyu, Mei-Ling; Huang, Zifang; Luo, Hongli

    In recent years, pervasive computing infrastructures have greatly improved the interaction between human and system. As we put more reliance on these computing infrastructures, we also face threats of network intrusion and/or any new forms of undesirable IT-based activities. Hence, network security has become an extremely important issue, which is closely connected with homeland security, business transactions, and people's daily life. Accurate and efficient intrusion detection technologies are required to safeguard the network systems and the critical information transmitted in the network systems. In this chapter, a novel network intrusion detection framework for mining and detecting sequential intrusion patterns is proposed. The proposed framework consists of a Collateral Representative Subspace Projection Modeling (C-RSPM) component for supervised classification, and an inter-transactional association rule mining method based on Layer Divided Modeling (LDM) for temporal pattern analysis. Experiments on the KDD99 data set and the traffic data set generated by a private LAN testbed show promising results with high detection rates, low processing time, and low false alarm rates in mining and detecting sequential intrusion detections.

  9. A simplified approach to true molar intrusion

    OpenAIRE

    Flieger Stefanie; Ziebura Thomas; Kleinheinz Johannes; Wiechmann Dirk

    2012-01-01

    Abstract Background Orthodontic management of anterior open bites is a demanding task for orthodontists. Molar intrusion as a primary means of open bite correction entails the need for appropriate anchorage. Orthodontic mini implants can provide the required mechanical support. The suggested procedure aims to reduce the risk of complications such as root damage or soft tissue irritations while minimizing overall complexity. Methods Three female patients aged 14, 18 and 19 years who decided ag...

  10. Perimeter intrusion detection and assessment system

    International Nuclear Information System (INIS)

    To obtain an effective perimeter intrusion detection system requires careful sensor selection, procurement, and installation. The selection process involves a thorough understanding of the unique site features and how these features affect the performance of each type of sensor. It is necessary to develop procurement specifications to establish acceptable sensor performance limits. Careful explanation and inspection of critical installation dimensions is required during on-site construction. The implementation of these activities at a particular site is discussed

  11. NETWORK INTRUSION DETECTION SYSTEM USING FUZZY LOGIC

    OpenAIRE

    Shanmugavadivu, R.; Nagarajan, Dr N.

    2011-01-01

    IDS which are increasingly a key part of system defense are used to identify abnormal activities in a computer system. In general, the traditional intrusion detection relies on the extensive knowledge of security experts, in particular, on their familiarity with the computer system to be protected. To reduce this dependence, variousdata-mining and machine learning techniques have been used in the literature. In the proposed system, we have designed fuzzy logic-based system for effectively ide...

  12. Standardized Parameterization of Intrusion Detection Systems

    OpenAIRE

    Björn-C. Bösch

    2012-01-01

    Efficiency of Intrusion Detection Systems (IDS) depends on their configuration and coverage of services. The coverage depends on used IDS. In the case of usage in multiple systems, operations might become complex because IDS configurations are still vendor-specific. This paper shows aspects and frame conditions for a multi-vendor IDS implementation under one central administration and notification entity. Subsequent it will be briefly discussed, why current management protocols are not adequa...

  13. Intrusion Detection using Continuous Time Bayesian Networks

    OpenAIRE

    Xu, Jing; Shelton, Christian R

    2014-01-01

    Intrusion detection systems (IDSs) fall into two high-level categories: network-based systems (NIDS) that monitor network behaviors, and host-based systems (HIDS) that monitor system calls. In this work, we present a general technique for both systems. We use anomaly detection, which identifies patterns not conforming to a historic norm. In both types of systems, the rates of change vary dramatically over time (due to burstiness) and over components (due to service differenc...

  14. Strategic Alert Throttling for Intrusion Detection Systems

    OpenAIRE

    Tedesco, Gianni; Aickelin, Uwe

    2008-01-01

    Network intrusion detection systems are themselves becoming targets of attackers. Alert flood attacks may be used to conceal malicious activity by hiding it among a deluge of false alerts sent by the attacker. Although these types of attacks are very hard to stop completely, our aim is to present techniques that improve alert throughput and capacity to such an extent that the resources required to successfully mount the attack become prohibitive. The key idea presented is to...

  15. A Review of Vapor Intrusion Models

    OpenAIRE

    Yao, Yijun; Suuberg, Eric M.

    2013-01-01

    A complete vapor intrusion (VI) model, describing vapor entry of volatile organic chemicals (VOCs) into buildings located on contaminated sites, generally consists of two main parts-one describing vapor transport in the soil and the other its entry into the building. Modeling the soil vapor transport part involves either analytically or numerically solving the equations of vapor advection and diffusion in the subsurface. Contaminant biodegradation must often also be included in this simulatio...

  16. Artificial Intrusion Detection Techniques: A Survey

    Directory of Open Access Journals (Sweden)

    Ashutosh Gupta

    2014-08-01

    Full Text Available Networking has become the most integral part of our cyber society. Everyone wants to connect themselves with each other. With the advancement of network technology, we find this most vulnerable to breach and take information and once information reaches to the wrong hands it can do terrible things. During recent years, number of attacks on networks have been increased which drew the attention of many researchers on this field. There have been many researches on intrusion detection lately. Many methods have been devised which are really very useful but they can only detect the attacks which already took place. These methods will always fail whenever there is a foreign attack which is not famous or which is new to the networking world. In order to detect new intrusions in the network, researchers have devised artificial intelligence technique for Intrusion detection prevention system. In this paper we are going to cover what types evolutionary techniques have been devised and their significance and modification.

  17. Radar, geologic, airborne gamma ray and Landsat TM digital data integration for geological mapping of the Estrela granite complex (Para State)

    International Nuclear Information System (INIS)

    This work is focused on the geotectonic context of the Carajas Mineral Province, Amazon Craton, which represents the most important Brazilian Mineral Province and hosts iron, cooper, gold, manganese and nickel deposits. At the end of Archean age, during the techno-metamorphic evolution, moderated alkaline granitoids were generated, such as, Estrela Granite Complex (EGC). This work has used digital integration products with the purpose of study the granite suite, its host rock, and the surrounded area. The digital integrated data were gamma-ray and geological data with satellite images (SAR-SAREX e TM-Landsat). The geophysics data, originally in 32 bits and grid format, were interpolated and converted to 8 bits images. The geological data (facies map) was digitalized and converted to a raster format. The remote sensing images were geometrically corrected to guarantee an accuracy on the geological mapping. On the data processing phase, SAR images were digital integrated with gamma-ray data, TM-Landsat image and the raster facies map. The IHS transformation was used as the technique to integrate the multi-source data. On the photogeological interpretation, SAR data were extremely important to permit the extraction of the main tectonic lineaments which occur on the following directions: +/- N45W, +/- N70W, +/- NS, +/- N20E, +/- N45E e +/- N75E. This procedure was done both in analogic and automatic form, being the automatic process more useful to complement information in the extracting process. Among the digital products generated, SAR/GAMA products (uranium, thorium and total count) were the ones that give the most important contribution. The interpretation of the SAR/GAMA's products added to the field campaign have allowed to map the limits of units that occur in the region and four facies of the Estrela Granite Complex were detected. The origin of the granite suite might be related to a magmatic differentiation or to distinct intrusion pulses. The use of the digital integrated products has showed to be extremely useful for basic geological mapping, especially to aid field campaign and the selection of key areas for detailed verification. As a final result, this research has allowed to propose obtained a geologic map of the Estrela Granite Complex area. (author)

  18. Radiation-associated chronic myelogenous leukaemia in younger people

    International Nuclear Information System (INIS)

    Chronic myelogenous leukaemia (CML) is known to be induced by exposure to ionizing radiation, as is acute leukaemia. However, CML has been recorded only rarely as a complication of radiation exposure early in life. During the period from 1973 to 1976, 75 patients with CML were admitted to Roswell Park Memorial Institute (RPMI). In addition, 64 patients admitted to RPMI previously were also available for study in 1973. Among 79 patients who were born after 1925, information regarding radiation exposure was obtained in 89%; 49 were interviewed and 21 responded to a mailed questionnaire. Consultation with parents was achieved in 52 of the 70 responding cases (74%). Replies were obtained from 15 of the 18 patients below the age of 25, and were confirmed by parents or siblings in all instances. Replies to the mailed questionnaire were obtained from 45 age- and sex-matched controls. In addition to two patients already known to have radiation exposure for treatment of malignant neoplasms, these inquiries yielded a total of nine patients with histories of radiation exposure for benign conditions. Three had therapeutic irradiation, two for thymic enlargement and one for eczema. Three had exposure in utero by pelvimetry. Two had diagnostic exposure during the perinatal period and one had occupational exposure as a nurse. Four of these patients were below the age of 25. All nine patients had the Ph' chromosome. The course of CML in these patients was not different from that of o patients was not different from that of other patients with Ph' chromosome-positive CML without a history of radiation exposure. A history of radiation exposure was elicited in one-fourth of the younger patients (<25) in this study, compared with one of 45 age- and sex-matched controls without leukaemia (p<0.02)

  19. Heinrich 0 at the Younger Dryas Termination Offshore Newfoundland

    Science.gov (United States)

    Pearce, C.; Andrews, J. T.; Jennings, A. E.; Bouloubassi, I.; Seidenkrantz, M. S.; Kuijpers, A.; Hillaire-Marcel, C.

    2014-12-01

    The last deglaciation was marked by intervals of rapid climatic fluctuations accompanied by glacial advances and retreats along the eastern edge of the Laurentide ice sheet. The most severe of these events, the Younger Dryas cold reversal, was accompanied by the major detrital carbonate (DC) event generally referred to as "Heinrich event 0" (H0) in the westernmost and southern Labrador Sea. A detrital carbonate layer was observed in a high resolution marine sediment record from southern Newfoundland and the onset of the event was dated to 11,600 ± 70 cal. yrs. BP (local ?R = 140 yrs.). A variety of different proxies was applied to investigate the transport mechanisms for deposition of the layer and provenance of the carbonates. Elevated concentrations of dolomite and calcite based on quantitative X-ray diffraction measurements, combined with the presence of several mature petrogenic biomarkers limit the source of the H0 detrital input to Palaeozoic carbonate outcrops in north-eastern Canada. The event is attributed to the rapid ice retreat from the Hudson Strait directly following the warming at the onset of the Holocene. Based on additional proxy data published earlier from the same record, the event succeeded the early Holocene resumption of the Atlantic Meridional Overturning Circulation (AMOC), indicating that the Hudson Strait meltwater event had probably no significant impact on the AMOC. The detrital carbonate layer can be found in other marine sediment records along the Labrador Current pathway, from Hudson Strait to the Grand Banks and the southern Newfoundland slope. By using the onset of deposition of the carbonates as a time-synchronous marker, the DC layer has great potential for improving marine chronologies of late glacial age in the region and evaluating spatial variations in ?R values.

  20. The Paleoproterozoic Djebel Drissa ring complex (Eglab shield, Algeria): Post-collisional intrusions in a transtentional tectonic setting

    Science.gov (United States)

    Merabet, Nacer-eddine; Mahdjoub, Yamina; Abtout, Abdeslam; Henry, Bernard; Kahoui, Mohamed; Maouche, Said; Lamali, Atmane; Ayache, Mohamed

    2014-08-01

    The Eburnean A-type granitic Djebel Drissa ring complex is part of the 2.08 Ga post-collisional Aftout magmatic suites that intruded the 2.22-2.09 Ga-old Paleoproterozoic granitoids i