Sample records for survey uncompahgre uplift

  1. Aerial gamma ray and magnetic survey: Uncompahgre Uplift Project, Montrose Quadrangle, Colorado. Final report

    Energy Technology Data Exchange (ETDEWEB)



    The quadrangle includes portions of the Colorado Plateau and southern Rocky Mountains Physiographic Provinces. The entire area of the Gunnison Uplift and parts of the Uncompahgre and Sawatch Uplifts are included. A part of the Piceance Basin and a segment of the Rio Grande Rift Valley are also included. A basement complex of Precambrian metamorphic and igneous rocks is exposed in the core of the Gunnison and Sawatch Uplifts in the Southern Rocky Mountains. Jurassic and Cretaceous age sedimentary rocks lie directly on the Precambrian basement in most places. They lie on Paleozoic rocks at the west edge of the Sawatch Uplift in the north-central part of the quadrangle. Triassic beds are mapped only in the canyon of the Uncompahgre River near the southwest corner of the quadrangle. A suite of Tertiary volcanics and some sedimentary rocks occupy extensive areas. Plutonic rocks of Tertiary and laramide age occupy only a small part of the quadrangle. The literature consulted included information on about 100 separate occurrences of radioactive minerals and/or anomalous radioactivity within the quadrangle. Many fracture and stratigraphically controlled forms are reported. Most of these occurrences are clustered in three areas: Cochetopa Creek, Cebolla Creek, and Marshall Pass. Important uranium production is recorded from deposits in the Cochetopa Creek and Marshall Pass areas. A total of 220 anomalies in the uranium channel meet the minimum requirements as defined in the Interpretation methods section of Volume I of this report. A few of them appear to be related to known economic deposits, and provide examples for comparison with anomalies in other parts of the quadrangle where radioactive mineral occurrences have not been reported.

  2. Geology and Ore Deposits of the Uncompahgre (Ouray) Mining District, Southwestern Colorado (United States)

    Burbank, Wilbur Swett; Luedke, Robert G.


    Formation, are chiefly tuff breccias of intermediate composition, which were deposited as extensive volcaniclastic aprons around volcanic centers to the east and south of the area. The Ouray area, in general, exhibits the typical effects of a minimum of three major uplifts of the ancestral San Juan Mountains. The earliest of these uplifts, with accompanying deformation and erosion, occurred within the Proterozoic, and the other two occurred at the close, respectively, of the Paleozoic and Mesozoic. The last event, known as the Laramide orogeny, locally was accompanied by extensive intrusion of igneous rocks of dominantly intermediate composition. Domal uplifts of the ancestral mountains resulted in peripheral monoclinal folds, plunging anticlines radial to the central core of the mountain mass, faults, and minor folds. The principal ore deposits of the Uncompahgre district were associated with crosscutting and laccolithic intrusions of porphyritic granodiorite formed during the Laramide (Late Cretaceous to early Tertiary) orogeny. The ores were deposited chiefly in the Paleozoic and Mesozoic sedimentary strata having an aggregate thickness of about 4,500 feet (ft) and occur beneath the early Tertiary unconformity, which in places truncated some of the uppermost deposits. A few ore deposits of late Tertiary age occur also in the sedimentary rocks near the southern margin of the district, but are restricted mostly to the overlying volcanic rocks. Ore deposits in the Uncompahgre district range from low-grade, contact-metamorphic through pyritic base-metal bodies containing silver and gold tellurides and native gold to silver-bearing lead-zinc deposits, and are zoned about the center of intrusive activity, a stock in an area referred to as The Blowout. Ore deposition within the Uncompahgre district was largely controlled by structural trends and axes of uplift established mainly in the late Paleozoic phase of deformation, but also in part by structural lin

  3. Uplifting Leadership (United States)

    Hargreaves, Andy; Boyle, Alan


    To find out how organizations turn failure into success, Andrew Hargreaves and his colleagues studied more than 15 business, sports, and education organizations. They found that the secret to these organizations' success came down to just two words: uplifting leadership. Uplifting leadership, write Hargreaves and Boyle in this article, raises the…

  4. Mobilization of selenium from the Mancos Shale and associated soils in the lower Uncompahgre River Basin, Colorado (United States)

    Mast, M. Alisa; Mills, Taylor J.; Paschke, Suzanne S.; Keith, Gabrielle; Linard, Joshua I.


    This study investigates processes controlling mobilization of selenium in the lower part of the Uncompahgre River Basin in western Colorado. Selenium occurs naturally in the underlying Mancos Shale and is leached to groundwater and surface water by limited natural runoff, agricultural and domestic irrigation, and leakage from irrigation canals. Soil and sediment samples from the study area were tested using sequential extractions to identify the forms of selenium present in solid phases. Selenium speciation was characterized for nonirrigated and irrigated soils from an agricultural site and sediments from a wetland formed by a leaking canal. In nonirrigated areas, selenium was present in highly soluble sodium salts and gypsum. In irrigated soils, soluble forms of selenium were depleted and most selenium was associated with organic matter that was stable under near-surface weathering conditions. Laboratory leaching experiments and geochemical modeling confirm that selenium primarily is released to groundwater and surface water by dissolution of highly soluble selenium-bearing salts and gypsum present in soils and bedrock. Rates of selenium dissolution determined from column leachate experiments indicate that selenium is released most rapidly when water is applied to previously nonirrigated soils and sediment. High concentrations of extractable nitrate also were found in nonirrigated soils and bedrock that appear to be partially derived from weathered organic matter from the shale rather than from agricultural sources. Once selenium is mobilized, dissolved nitrate derived from natural sources appears to inhibit the reduction of dissolved selenium leading to elevated concentrations of selenium in groundwater. A conceptual model of selenium weathering is presented and used to explain seasonal variations in the surface-water chemistry of Loutzenhizer Arroyo, a major tributary contributor of selenium to the lower Uncompahgre River.

  5. The evolution of the southern California uplift, 1955 through 1976 (United States)

    Castle, Robert O.; Elliot, Michael R.; Church, Jack P.; Wood, Spencer H.


    between 1953 and 1976. Exceptions to this generalization consist largely of the results of pre-1953 surveys through the western Transverse Ranges and the eastern Mojave Desert. Errors in measured height differences derive from blunders, systematic survey errors, random survey errors, improperly formulated orthometric corrections, and intrasurvey movement; the last of these has created the most serious problems encountered in our reconstruction of the basic data. A variety of independent tests indicate that survey error associated with the utilized levelings was generally small and fell largely within the predicted random-error range. Moreover, the redundancy and coherence displayed by the entire data set provide convincing evidence of survey accuracy and the virtual absence of height- and slope-dependent error in particular. Our reconstructions of the changing configuration of the uplift derive chiefly from comparisons among sequentially developed observed elevations along the same route. Most of the observed elevations from which the vertical displacements were computed have been reconstructed with respect to bench mark Tidal 8, San Pedro, as invariant in height. Because the San Pedro tide station has been characterized by a history of modest relative uplift, vertical displacements referred to this station are biased slightly toward the appearance of subsidence. Where the observed elevations cannot be conveniently tied to Tidal 8, they have been referred to secondary control points whose history with respect to Tidal 8 can be independently established. Each of the lines of observed elevation changes provides, accordingly, a section athwart or along the axis of the uplift from which the changes in the configuration of the uplift can be roughly generalized. Because relatively few surveys were run in 1955, which we choose as a representative temporal datum, we have commonly incorporated the results of earlier or of somewhat later levelings as the equivalents of 1955 surveys

  6. Continuous uplift near the seaward edge of the Prince William Sound megathrust: Middleton Island, Alaska (United States)

    Savage, James C.; Plafker, George; Svarc, Jerry L.; Lisowski, Michael


    Middleton Island, located at the seaward edge of the continental shelf 50 km from the base of the inner wall of the Aleutian Trench, affords an opportunity to make land-based measurements of uplift near the toe of the Prince William Sound megathrust, site of the 1964, M = 9.2, Alaska earthquake. Leveling surveys (1973–1993) on Middleton Island indicate roughly uniform tilting (~1 µrad/a down to the northwest) of the island, and GPS surveys (1993–2012) show an uplift rate of 14 mm/a of the island relative to fixed North America. The data are consistent with a combined (coseismic and postseismic) uplift (in meters) due to the 1964 earthquake as a function of time τ (years after the earthquake) u(τ) = (3.5 + 1.21 log10 [1 + 1.67 τ]) H(τ) where 3.5 is the coseismic uplift and H(τ) is 0 for τ < 0 and 1 otherwise. The current uplift on Middleton Island is attributed to continuous slip on a fault splaying off from the megathrust, and the long-term uplift is the superposition of the effects of past earthquakes, each earthquake being similar to the 1964 event. Then, the predicted uplift at time t due to a sequence of earthquakes at times tiwould be . From studies of strandlines associated with the uplifted terraces on Middleton Island, Plafker et al. (1992) estimated the occurrence times of the last six earthquakes and measured the present-day elevations of those strandlines. The predicted uplift is in rough agreement with those measurements. About half of the predicted uplift is due to postseismic relaxation from previous earthquakes.

  7. Accidental inflation from Kaehler uplifting

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Dayan, Ido; Westphal, Alexander; Wieck, Clemens [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany). Theory Group; Jing, Shenglin [Toronto Univ., ON (Canada). Canadian Inst. for Theoretical Astrophysics; Toronto Univ., ON (Canada). Dept. of Astronomy and Astrophysics


    We analyze the possibility of realizing inflation with a subsequent dS vacuum in the Kaehler uplifting scenario. The inclusion of several quantum corrections to the 4d effective action evades previous no-go theorems and allows for construction of simple and successful models of string inflation. The predictions of several benchmark models are in accord with current observations, i.e., a red spectral index, negligible non-gaussianity, and spectral distortions similar to the simplest models of inflation. A particularly interesting subclass of models are ''left-rolling'' ones, where the overall volume of the compactified dimensions shrinks during inflation. We call this phenomenon ''inflation by deflation'' (IBD), where deflation refers to the internal manifold. This subclass has the appealing features of being insensitive to initial conditions, avoiding the overshooting problem, and allowing for observable running {alpha}<{proportional_to}0.012 and enhanced tensor-to-scalar ratio r{proportional_to}10{sup -5}. The latter results differ significantly from many string inflation models.

  8. GPS Imaging of Sierra Nevada Uplift (United States)

    Hammond, W. C.; Blewitt, G.; Kreemer, C.


    Recent improvements in the scope and precision of GPS networks across California and Nevada have allowed for uplift of the Sierra Nevada to be observed directly. Much of the signal, in the range of 1 to 2 mm/yr, has been attributed to lithospheric scale rebound following massive groundwater withdrawal in the San Joaquin Valley in southern California, exacerbated by drought since 2011. However, natural tectonic deformation associated with long term uplift of the range may also contribute to the observed signal. We have developed new algorithms that enhance the signal of Sierra Nevada uplift and improve our ability to interpret and separate natural tectonic signals from anthropogenic contributions. We apply our new Median Interannual Difference Adjusted for Skewness (MIDAS) algorithm to the vertical times series and a inverse distance-weighted median spatial filtering and Delaunay-based interpolation to despeckle the rate map. The resulting spatially continuous vertical rate field is insensitive to outliers and steps in the GPS time series, and omits isolated features attributable to unstable stations or unrepresentative rates. The resulting vertical rate field for California and Nevada exhibits regionally coherent signals from the earthquake cycle including interseismic strain accumulation in Cascadia, postseismic relaxation of the mantle from recent large earthquakes in central Nevada and southern California, groundwater loading changes, and tectonic uplift of the Sierra Nevada and Coast Ranges. Uplift of the Sierra Nevada extends from the Garlock Fault in the south to an indefinite boundary in the north near the latitude of Mt. Lassen to the eastern Sierra Nevada range front in Owen's Valley. The rates transition to near zero in the southern Walker Lane. The eastern boundary of uplift coincides with the highest strain rates in the western Great Basin, suggesting higher normal fault slip rates and a component of tectonic uplift of the Sierra Nevada.

  9. Detailed study of selenium and other constituents in water, bottom sediment, soil, alfalfa, and biota associated with irrigation drainage in the Uncompahgre Project area and in the Grand Valley, west-central Colorado, 1991-93 (United States)

    Butler, D.L.; Wright, W.G.; Stewart, K.C.; Osmundson, B.C.; Krueger, R.P.; Crabtree, D.W.


    In 1985, the U.S. Department of the Interior began a program to study the effects of irrigation drainage in the Western United States. These studies were done to determine whether irrigation drainage was causing problems related to human health, water quality, and fish and wildlife resources. Results of a study in 1991-93 of irrigation drainage associated with the Uncompahgre Project area, located in the lower Gunnison River Basin, and of the Grand Valley, located along the Colorado River, are described in this report. The focus of the report is on the sources, distribution, movement, and fate of selenium in the hydrologic and biological systems and the effects on biota. Generally, other trace- constituent concentrations in water and biota were not elevated or were not at levels of concern. Soils in the Uncompahgre Project area that primarily were derived from Mancos Shale contained the highest concentrations of total and watrer-extractable selenium. Only 5 of 128\\x11alfalfa samples had selenium concentrations that exceeded a recommended dietary limit for livestock. Selenium data for soil and alfalfa indicate that irrigation might be mobilizing and redistributing selenium in the Uncompahgre Project area. Distribution of dissolved selenium in ground water is affected by the aqueous geochemical environment of the shallow ground- water system. Selenium concentrations were as high as 1,300\\x11micrograms per liter in water from shallow wells. The highest concentrations of dissolved selenium were in water from wells completed in alluvium overlying the Mancos Shale of Cretaceous age; selenium concentrations were lower in water from wells completed in Mancos Shale residuum. Selenium in the study area could be mobilized by oxidation of reduced selenium, desorption from aquifer sediments, ion exchange, and dissolution. Infiltration of irrigation water and, perhaps nitrate, provide oxidizing conditions for mobilization of selenium from alluvium and shale residuum and for

  10. Uplifting non-compact gauged supergravities

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    Baron, Walter H.; Dall’Agata, Gianguido [Dipartimento di Fisica e Astronomia “Galileo Galilei”,Università di Padova, Via Marzolo 8, 35131 Padova (Italy); INFN - Sezione di Padova Via Marzolo 8, 35131 Padova (Italy)


    We provide the M-theory uplift of de Sitter vacua of SO(5,3) and SO(4,4) gaugings of maximal supergravity in 4 dimensions. We find new non-compact backgrounds that are squashed hyperboloids with non-trivial flux for the 3-form potential. The uplift requires a new non-linear ansatz for the 11-dimensional metric and for the 3-form potential that reduces to the known one leading to the 7-sphere solution in the case of the SO(8) gauging.

  11. F-Theory Uplifts and GUTs

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    Blumenhagen, Ralph; /Munich, Max Planck Inst.; Grimm, Thomas W.; /Bonn U.; Jurke, Benjamin; /Munich, Max Planck Inst.; Weigand, Timo; /SLAC


    We study the F-theory uplift of Type IIB orientifold models on compact Calabi-Yau threefolds containing divisors which are del Pezzo surfaces. We consider two examples defined via del Pezzo transitions of the quintic. The first model has an orientifold projection leading to two disjoint O7-planes and the second involution acts via an exchange of two del Pezzo surfaces. The two uplifted fourfolds are generically singular with minimal gauge enhancements over a divisor and, respectively, a curve in the non-Fano base. We study possible further degenerations of the elliptic fiber leading to F-theory GUT models based on subgroups of E{sub 8}.

  12. Glacial isostatic uplift of the European Alps

    NARCIS (Netherlands)

    Mey, Jürgen; Scherler, Dirk; Wickert, Andrew D.; Egholm, David L.; Tesauro, Magdala; Schildgen, Taylor F.; Strecker, Manfred R.


    Following the last glacial maximum (LGM), the demise of continental ice sheets induced crustal rebound in tectonically stable regions of North America and Scandinavia that is still ongoing. Unlike the ice sheets, the Alpine ice cap developed in an orogen where the measured uplift is potentially

  13. Respite Care, Stress, Uplifts, and Marital Quality in Parents of Children with Down Syndrome (United States)

    Norton, Michelle; Dyches, Tina Taylor; Harper, James M.; Roper, Susanne Olsen; Caldarella, Paul


    Parents of children with disabilities are at risk for high stress and low marital quality; therefore, this study surveyed couples (n = 112) of children with Down syndrome (n = 120), assessing whether respite hours, stress, and uplifts were related to marital quality. Structural equation modeling indicated that respite hours were negatively related…

  14. Controls on selenium distribution and mobilization in an irrigated shallow groundwater system underlain by Mancos Shale, Uncompahgre River Basin, Colorado, USA (United States)

    Mills, Taylor J.; Mast, M. Alisa; Thomas, Judith C.; Keith, Gabrielle L.


    Elevated selenium (Se) concentrations in surface water and groundwater have become a concern in areas of the Western United States due to the deleterious effects of Se on aquatic ecosystems. Elevated Se concentrations are most prevalent in irrigated alluvial valleys underlain by Se-bearing marine shales where Se can be leached from geologic materials into the shallow groundwater and surface water systems. This study presents groundwater chemistry and solid-phase geochemical data from the Uncompahgre River Basin in Western Colorado, an irrigated alluvial landscape underlain by Se-rich Cretaceous marine shale. We analyzed Se species, major and trace elements, and stable nitrogen and oxygen isotopes of nitrate in groundwater and aquifer sediments to examine processes governing selenium release and transport in the shallow groundwater system. Groundwater Se concentrations ranged from below detection limit (< 0.5 μg L− 1) to 4070 μg L− 1, and primarily are controlled by high groundwater nitrate concentrations that maintain oxidizing conditions in the aquifer despite low dissolved oxygen concentrations. High nitrate concentrations in non-irrigated soils and nitrate isotopes indicate nitrate is largely derived from natural sources in the Mancos Shale and alluvial material. Thus, in contrast to areas that receive substantial NO3 inputs through inorganic fertilizer application, Se mitigation efforts that involve limiting NO3 application might have little impact on groundwater Se concentrations in the study area. Soluble salts are the primary source of Se to the groundwater system in the study area at-present, but they constitute a small percentage of the total Se content of core material. Sequential extraction results indicate insoluble Se is likely composed of reduced Se in recalcitrant organic matter or discrete selenide phases. Oxidation of reduced Se species that constitute the majority of the Se pool in the study area could be a potential source of Se in

  15. SUTRA model used to evaluate the role of uplift and erosion in the persistence of saline groundwater in the shallow subsurface (United States)

    U.S. Geological Survey, Department of the Interior — A modified version of the three-dimensional, variable-density solute-transport model (SUTRA) was developed to simulate the effects of erosion and uplift on the...

  16. The central uplift of Ritchey crater, Mars (United States)

    Ding, Ning; Bray, Veronica J.; McEwen, Alfred S.; Mattson, Sarah S.; Okubo, Chris H.; Chojnacki, Matthew; Tornabene, Livio L.


    Ritchey crater is a ∼79 km diameter complex crater near the boundary between Hesperian ridged plains and Noachian highland terrain on Mars (28.8°S, 309.0°E) that formed after the Noachian. High Resolution Imaging Science Experiment (HiRISE) images of the central peak reveal fractured massive bedrock and megabreccia with large clasts. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) spectral analysis reveals low calcium pyroxene (LCP), olivine (OL), hydrated silicates (phyllosilicates) and a possible identification of plagioclase bedrock. We mapped the Ritchey crater central uplift into ten units, with 4 main groups from oldest and originally deepest to youngest: (1) megabreccia with large clasts rich in LCP and OL, and with alteration to phyllosilicates; (2) massive bedrock with bright and dark regions rich in LCP or OL, respectively; (3) LCP and OL-rich impactites draped over the central uplift; and (4) aeolian deposits. We interpret the primitive martian crust as igneous rocks rich in LCP, OL, and probably plagioclase, as previously observed in eastern Valles Marineris. We do not observe high-calcium pyroxene (HCP) rich bedrock as seen in Argyre or western Valles Marineris. The association of phyllosilicates with deep megabreccia could be from impact-induced alteration, either as a result of the Richey impact, or alteration of pre-existing impactites from Argyre basin and other large impacts that preceded the Ritchey impact, or both.

  17. The central uplift of Ritchey crater, Mars (United States)

    Ding, Ning; Bray, Veronica J.; McEwen, Alfred S.; Mattson, Sarah S.; Okubo, Chris H.; Chojnacki, Matthew; Tornabene, Livio L.


    Ritchey crater is a ∼79 km diameter complex crater near the boundary between Hesperian ridged plains and Noachian highland terrain on Mars (28.8°S, 309.0°E) that formed after the Noachian. High Resolution Imaging Science Experiment (HiRISE) images of the central peak reveal fractured massive bedrock and megabreccia with large clasts. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) spectral analysis reveals low calcium pyroxene (LCP), olivine (OL), hydrated silicates (phyllosilicates) and a possible identification of plagioclase bedrock. We mapped the Ritchey crater central uplift into ten units, with 4 main groups from oldest and originally deepest to youngest: (1) megabreccia with large clasts rich in LCP and OL, and with alteration to phyllosilicates; (2) massive bedrock with bright and dark regions rich in LCP or OL, respectively; (3) LCP and OL-rich impactites draped over the central uplift; and (4) aeolian deposits. We interpret the primitive martian crust as igneous rocks rich in LCP, OL, and probably plagioclase, as previously observed in eastern Valles Marineris. We do not observe high-calcium pyroxene (HCP) rich bedrock as seen in Argyre or western Valles Marineris. The association of phyllosilicates with deep megabreccia could be from impact-induced alteration, either as a result of the Richey impact, or alteration of pre-existing impactites from Argyre basin and other large impacts that preceded the Ritchey impact, or both.

  18. Controls on selenium distribution and mobilization in an irrigated shallow groundwater system underlain by Mancos Shale, Uncompahgre River Basin, Colorado, USA

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Taylor J.; Mast, M. Alisa; Thomas, Judith; Keith, Gabrielle


    Elevated selenium (Se) concentrations in surface water and groundwater have become a concern in areas of the Western United States due to the deleterious effects of Se on aquatic ecosystems. Elevated Se concentrations are most prevalent in irrigated alluvial valleys underlain by Se-bearing marine shales where Se can be leached from geologic materials into the shallow groundwater and surface water systems. This study presents groundwater chemistry and solid-phase geochemical data from the Uncompahgre River Basin in Western Colorado, an irrigated alluvial landscape underlain by Se-rich Cretaceous marine shale. We analyzed Se species, major and trace elements, and stable nitrogen and oxygen isotopes of nitrate in groundwater and aquifer sediments to examine processes governing selenium release and transport in the shallow groundwater system. Groundwater Se concentrations ranged from below detection limit (< 0.5 μg L{sup −1}) to 4070 μg L{sup −1}, and primarily are controlled by high groundwater nitrate concentrations that maintain oxidizing conditions in the aquifer despite low dissolved oxygen concentrations. High nitrate concentrations in non-irrigated soils and nitrate isotopes indicate nitrate is largely derived from natural sources in the Mancos Shale and alluvial material. Thus, in contrast to areas that receive substantial NO{sub 3} inputs through inorganic fertilizer application, Se mitigation efforts that involve limiting NO{sub 3} application might have little impact on groundwater Se concentrations in the study area. Soluble salts are the primary source of Se to the groundwater system in the study area at-present, but they constitute a small percentage of the total Se content of core material. Sequential extraction results indicate insoluble Se is likely composed of reduced Se in recalcitrant organic matter or discrete selenide phases. Oxidation of reduced Se species that constitute the majority of the Se pool in the study area could be a potential


    Indian Academy of Sciences (India)

    IN a series of papers published in these Proceedings and in the Memoirs of the Irrigation Research 1 nstitute, investigations on the effect of single sheet piles on the uplift pressure on floors have been reported. In the present paper, the results of an investigation on the effect of two sheet piles on the uplift pressure are given.

  20. The upliftment in the Mejillones peninsula during 1995-2015 with two subduction earthquakes (United States)

    Narayan Shrivastava, Mahesh; Gonzalez, Gabriel; Moreno, Marcos


    The Mejillones peninsula in northern Chile show the significant Quaternary surface uplift, which contrast with the surrounding coastal areas. The continuous GPS sites in this peninsula have detected significant upliftment during propagation of subduction earthquakes. The Mejillones peninsula region shows the low locking degree [Métois et al., 2013 & Bejar et al., 2014] and acts as a seismic barrier for the last two megathrust earthquakes such as 1995, Mw 8.1 Antofagasta earthquake and the 2007, Mw 7.7 Tocopilla earthquake in the south and north of peninsula. However, significant afterslip has taken place beneath the Mejillones peninsula in both earthquakes. We describe the vertical deformation in the Mejillones peninsula with the megathrust architecture during 1995-2015 with megathrust earthquakes and locking degree. We simulate the vertical displacement with the coseismic slip and 3.3 years afterslip of Antofagasta, 1995 by [Chlieh et al., 2004] and coseismic slip and 3.3 years of afterslip of Tocopilla earthquake 2007 modeled in this present study. With both earthquakes due to coseismic slip and afterslip in 3.3 years, Mejillones peninsula has exhibited 105 cm cumulative upliftment at the JRGN GPS site. The modeled new locking model by additional dataset of continuous and survey GPS from 2012-2015, it shows the low locking degree in the Mejillones peninsula region confirming the previous locking models. Our interseismic model and observation suggest that JRGN Continuous GPS site shows subsidence rate 2.0 mm/year after the Tocopilla earthquake 2007. But in contrast the continuous GPS sites UCNF, PB05 and VLZL show the significant upliftment. By considering the modeled locking degree same during 1995 to 2015, we conclude that Mejillones peninsula would have remained upliftment 98 cm. The vertical tectonic rate fluctuates at various timescale in the subduction zones, the study of elevated shorelines may provide an efficient tool to develop our understanding of long

  1. Topographic form of the Coast Ranges of the Cascadia Margin in relation ot coastal uplift rates and plate subduction (United States)

    Kelsey, Harvey M.; Engebretson, David C.; Mitchell, Clifton E.; Ticknor, Robert L.


    The Coast Ranges of the Cascadia margin are overriding the subducted Juan de Fuca/Gorda plate. We investigate the extent to which the latitudinal change in attributes related to the subduction process. These attributes include the varibale age of the subducted slab that underlies the Coast Ranges and average vertical crustal velocities of the western margin of the Coast Rnages for two markedly different time periods, the last 45 years and the last 100 kyr. These vertical crustal velocities are computed from the resurveying of highway bech marks and from the present elevation of shore platforms that have been uplifted in the late Quaternary, respectively. Topogarphy of the Coast Ranges is in part a function of the age and bouyancy of the underlying subducted plate. This is evident in the fact that the two highest topographic elements of the Coast Rnages, the Klamath Mountains and the Olympic Mountains, are underlain by youngest subducted oceanic crust. The subducted Blanco Fracture Zone in southernmost Oregon is responsible for an age discontinuity of subducted crust under the Klamath Mountains. The norhtern terminus of hte topographically higher Klamaths is offset to the north relative to the position of the underlying Blanco Fracture Zone, teh offset being in the direction of migration of the farcture zone, as dictated by relative plate motions. Vertical crustal velocities at the coast, derived from becnh mark surveys, are as much as an order of magnitude greater than vertical crustal velocities derived from uplifted shore platforms. This uplift rate discrepancy indicates that strain is accumulating on the plate margin, to be released during the next interplate earthquake. In a latitudinal sense, average Coast Rnage topography is relatively high where bench mark-derived, short-term vertical crustal velocities are highest. Becuase the shore platform vertical crustal velocities reflect longer-term, premanent uplift, we infer that a small percentage of the

  2. Competition between uplift and transverse sedimentation in an experimental delta (United States)

    Grimaud, Jean-Louis; Paola, Chris; Ellis, Chris


    Mass is commonly injected into alluvial systems either laterally by transport from source regions or vertically from below via local uplift. We report results on the competition between these two fundamental processes, using an experimental basin with a deformable substrate. The lateral supply is via two alluvial fans on orthogonal walls of the basin; the uplifting region is downstream of one of the fans (axial) and opposite to the other (transverse). We show that the presence of a transverse sediment input increases the erosion rate of the uplifting region by pushing the mixing zone between the two alluvial sources against the uplifting mass. However, increase in sediment delivery to the transverse fan does not cause a proportional increase in erosion rate of the uplifting region. Instead, the system reaches a steady state balance between uplift and erosion induced by the transverse fan, such that there is no change in the total mass above the active alluvial surface—a lateral analog of the classical steady state between vertical erosion and uplift. We also show that the mixing zone is instrumental in limiting upstream aggradation and funneling sediments to the shore, resulting in limited river lateral mobility and increased shoreline progradation. Hence, the interaction between alluvial sources buffers river erosion and leads to consistent deviations from predictions of the area of influence of each fan based on simple mass-balance arguments. In the Ganges-Brahmaputra-Meghna delta, we suggest that similar dynamics help stabilize the Brahmaputra River course in the Jamuna Valley during Holocene time.

  3. Control of paleoshorelines by trench forebulge uplift, Loyalty Islands (United States)

    Dickinson, William R.


    Unlike most tropical Pacific islands, which lie along island arcs or hotspot chains, the Loyalty Islands between New Caledonia and Vanuatu owe their existence and morphology to the uplift of pre-existing atolls on the flexural forebulge of the New Hebrides Trench. The configuration and topography of each island is a function of distance from the crest of the uplifted forebulge. Both Maré and Lifou are fully emergent paleoatolls upon which ancient barrier reefs form highstanding annular ridges that enclose interior plateaus representing paleolagoon floors, whereas the partially emergent Ouvea paleoatoll rim flanks a drowned remnant lagoon. Emergent paleoshoreline features exposed by island uplift include paleoreef flats constructed as ancient fringing reefs built to past low tide levels and emergent tidal notches incised at past high tide levels. Present paleoshoreline elevations record uplift rates of the islands since last-interglacial and mid-Holocene highstands in global and regional sea levels, respectively, and paleoreef stratigraphy reflects net Quaternary island emergence. The empirical uplift rates vary in harmony with theoretical uplift rates inferred from the different positions of the islands in transit across the trench forebulge at the trench subduction rate. The Loyalty Islands provide a case study of island environments controlled primarily by neotectonics.

  4. Recent uplift of the Atlantic Atlas (offshore West Morocco): Tectonic arch and submarine terraces (United States)

    Benabdellouahed, M.; Klingelhoefer, F.; Gutscher, M.-A.; Rabineau, M.; Biari, Y.; Hafid, M.; Duarte, J. C.; Schnabel, M.; Baltzer, A.; Pedoja, K.; Le Roy, P.; Reichert, C.; Sahabi, M.


    Re-examination of marine geophysical data from the continental margin of West Morocco reveals a broad zone characterized by deformation, active faults and updoming offshore the High Atlas (Morocco margin), situated next to the Tafelney Plateau. Both seismic reflection and swath-bathymetric data, acquired during Mirror marine geophysical survey in 2011, indicate recent uplift of the margin including uplift of the basement. This deformation, which we propose to name the Atlantic Atlas tectonic arch, is interpreted to result largely through uplift of the basement, which originated during the Central Atlantic rifting stage - or even during phases of Hercynian deformation. This has produced a large number of closely spaced normal and reverse faults, ;piano key faults;, originating from the basement and affecting the entire sedimentary sequence, as well as the seafloor. The presence of four terraces in the Essaouira canyon system at about 3500 meters water depth and ;piano key faults; and the fact that these also affect the seafloor, indicate that the Atlantic Atlas is still active north of Agadir canyon. We propose that recent uplift is causing morphogenesis of four terraces in the Essaouira canyon system. In this paper the role of both Canary plume migration and ongoing convergence between the African and Eurasian plates in the formation of the Atlantic Atlas are discussed as possibilities to explain the presence of a tectonic arch in the region. The process of reactivation of passive margins is still not well understood. The region north of Agadir canyon represents a key area to better understand this process.

  5. Radiogenic isotopes of arc lavas constrain uplift of the Andes (United States)

    Scott, Erin; Allen, Mark B.; Macpherson, Colin; McCaffrey, Ken; Davidson, Jon; Saville, Christopher


    Orogenic plateaux are an ultimate expression of continental tectonics, but the timings and mechanisms of their formation are far from understood. The elevation history of the Andes is of particular importance for climatic reconstructions, as they pose the only barrier to atmospheric circulation in the Southern Hemisphere. Many varied techniques have been utilized over the last two decades to constrain Andean Plateau (AP) surface uplift. Two conflicting schools of thought are prominent: (1) recent, rapid rise since 10-6 Ma (Late Miocene), and (2) slow, continued uplift from 40 Ma. We propose a new, independent, approach to constrain AP surface uplift through time. By comparing isotopic compositions of Andean Quaternary arc lavas to present day crustal thickness and topography, we show that Sr and Nd isotopes are effective discriminants for the modern extent of the AP. As previously described, these isotopic systems are sensitive to crustal contamination, which in turn relates to crustal thickness, and, via isostasy, to regional surface elevation. We apply this relationship to a new compilation of published, age corrected, isotopic compositions of arc lavas, to constrain the surface uplift history of the Andes from the Jurassic to present day. Our results are consistent with significant AP surface uplift beginning in the Mid to Late Paleogene. We show that by 23 Ma, the AP was established at close to its modern elevations between at least 16-28 deg. S, thereby predating models for Late Miocene surface uplift. Between 23-10 Ma, surface uplift propagated south of 28 deg. S by a further 400 km. Our model has implications for understanding magma plumbing systems in regions of thick, wide crust, especially other orogenic plateaux.

  6. Uplift Capacity of Inclined Underreamed Piles Subjected to Vertical Load (United States)

    Rahman, Md. Akilur; Sengupta, Siddhartha


    Many offshore structures are subjected to overturning moments due to wind load, wave pressure, and ship impacts. Inclined (batter) piles are used to support such structures, and to carry the horizontal and vertical loads resulted from the overturning moments. Though studies have been done with inclined piles having no underream bulb, little information is available in the literature about estimating the uplift capacity of inclined underreamed piles. In the present study laboratory experiments have been done with vertically loaded model piles having no underream as well as with one and two underreams. The piles were positioned at angle of inclination of θ = 0°, 10°, 20°, 30° (with vertical); and placed in locally available sand under vertical uplift load. Three different pile stem diameters (D = 20, 25, and 35 mm) were used. The corresponding pile length to stem diameter (l/D) ratio were 18, 14, and 10 respectively. Experiments had been conducted with two relative different densities (45 and 70%) of sand. The failure uplift loads were obtained in each case. It had been found that for inclined piles increase in number of underream bulbs from 0 to 2 was quite effective in resisting uplift loads corresponding to piles having l/D equals to 10. The percentage decreases in uplift capacity corresponding to increase in inclination angle were more pronounced for piles with double underreams.

  7. Raised marine terraces in the Northern Calabrian Arc (Southern Italy: a ~ 600 kyr-long geological record of regional uplift

    Directory of Open Access Journals (Sweden)

    L. Cucci


    Full Text Available The Sibari Plain in the Northeastern Calabrian Arc displays a well-developed suite of marine terraces. This paper deals with i the identification and correlation of the terraces; ii their age assignment and a tentative reconstruction of the uplift history of the area; iii the relationships between terraces and major faults in the study area and between uplift in the Plain and pattern of Quaternary uplift throughout the Calabrian Arc. Identifying wavecut platforms and inner-edge fragments over a linear extent of ~ 100 km was achieved by photo interpretation, 1:25 000 scale map analyses and field survey. Morphological evidence led to the correlation of the identified fragments into five complete strandlines (numbered #1 to #5 lowest to highest, at elevations ranging from 60 m to ~ 650 m. Analysis of two parameters of the emerged platform-cliff systems, namely the platform-cliff ratio and the dissection percentage, further testifies that the two lowest terraces are strongly correlative. A 130 kyr AAR age of in situ fossil samples of Glycymeris collected at 114 m elevation within the deposit of Terrace #2 indicates a key correlation of T#2 with MIS 5.5 (the peak of the last interglacial, 124 kyr, i.e. an uplift rate of ~ 0.98 mm/yr for this strandline. The other four terraces have been tentatively associated with MIS 5.3, 7, 9 and 15. Geological observations independent of geochronological evidence provide consistent lower age boundaries for the terraces and supply further constraints to this interpretation. Investigating the relations between setting of the terraces and location of major tectonic structures in the region is suggestive of no recent activity of two previously recognized faults, the «Sangineto Line» and the «Corigliano-Rossano Line». Instead, some limited anomalies that affect the terraces are tentatively associated with the activity of the Castrovillari Fault. Therefore, sustained uplift has been the long-term dominant

  8. Cenozoic uplift and subsidence in the North Atlantic region

    DEFF Research Database (Denmark)

    Anell, Ingrid Anna Margareta; Thybo, Hans; Artemieva, Irina


    , time and amplitude (where possible) of topographic changes in the North Atlantic region during the Cenozoic (65-0 Ma). Our compilation is based on published results from reflection seismic studies, AFT (apatite fission track) studies, VR (vitrinite reflectance) trends, maximum burial, sediment supply...... studies, mass balance calculations and extrapolation of seismic profiles to onshore geomorphological features. The integration of about 200 published results reveal a clear pattern of topographic changes in the North Atlantic region during the Cenozoic: (1) The first major phase of Cenozoic regional...... uplift occurred in the late Palaeocene-early Eocene (ca 60-50 Ma), probably related to the break-up of the North Atlantic between Europe and Greenland, as indicated by the northward propagation of uplift. It was preceded by middle Palaeocene uplift and over-deepening of some basins of the North Sea...

  9. Evidence for Holocenic uplift at Somma-Vesuvius (United States)

    Marturano, Aldo; Aiello, Giuseppe; Barra, Diana; Fedele, Lorenzo; Grifa, Celestino; Morra, Vincenzo; Berg, Ria; Varone, Antonio


    Detailed stratigraphical, archaeological, micropalaeontological, archaeometrical and petrochemical analyses of samples from trenches and boreholes at insula of Casti Amanti, in Pompeii, allowed a faithful reconstruction of the recent environmental evolution of the site. The present data clearly indicate the alternation of both subaerial and shallow marine conditions during Holocene times. Taking into account the relative local sea level variations, a ~ 30 m ground uplift event in the last 6 kyr (with an average vertical uplift rate of ~ 5 mm/yr) was inferred for the first time.

  10. Analysis of uplift bearing capacity of pile based on ABAQUS (United States)

    Li, Bin; Fu, Jianbao


    The uplift bearing capacity of pile in soil foundation is mainly obtained by load test, which is time-consuming and low-efficiency. A small sliding model and the contact pairs in large-scale finite element software ABAQUS are used to simulate the friction between pile and soil, and a good fitting curve of pile foundation bearing capacity is obtained. According to the results of finite element software, the lateral friction of the pile is fully developed, and the stress of the pile gradually reaches the ultimate pullup capacity with the increase of pile displacement. The finite element software ABAQUS can be used to simulate uplift capacity of pile.

  11. Quaternary Uplift of Coral Terraces from Active Folding and Thrusting Along the Northern Coast of Timor-Leste (United States)

    Cox, N. L.; Harris, R.; Merritts, D.


    Emergent coral terraces along the northern coast of Timor-Leste, reveal differential vertical strain along the strike of the active Banda arc-continent collision complex. The number of major coral terraces in surveyed profiles increases from 2 to 25 along a coastal distance of 150 km from central to eastern Timor-Leste. Comparison of 8 separate terrace profiles with sea level curves predicts vertical displacement rates that increase eastward from <0.3 to 1.0-1.5 mm/year. This pattern is corroborated by U-series age analyses that document non-linear increases in vertical strain eastward with the uplift rates ranging from <.04 to 2.0 mm/year. U-series ages also indicates the occurrence of both erosional (regressional) and depositional terraces. Two profiles, dominated by erosional terraces, have associated local lower depositional terraces. The erosional terraces are more abundant, but yield apparent lower uplift rates in comparison with the depositional terraces. This occurrence questions the validity of uplift rates obtained by age analysis for the errosional terraces and/or aids in the conclusion that differential vertical strain not only exists with distance between profiles but with time for each profile. We associate active uplift with northward movement along retro- wedge thrust faults that are well documented in seismic reflection profiles adjacent to the north coast of Timor- Leste.

  12. Late Holocene uplift of the Izu Islands on the northern Zenisu Ridge off Central Japan (United States)

    Kitamura, Akihisa; Imai, Takafumi; Mitsui, Yuta; Ito, Mami; Miyairi, Yosuke; Yokoyama, Yusuke; Tokuda, Yuki


    To clarify the Holocene uplift history of the Izu Islands, Japan, we analyze the elevations and 14C ages of emerged sessile assemblages measured by accelerator mass spectrometry (AMS) on the islands of Niijima, Jinaijima, Shikinejima, and Kouzushima, on the northern Zenisu Ridge. The results suggest that uplift events took place after AD 1950 (uplift event 1), during AD 786-1891 (uplift event 2), during AD 600-1165 (uplift event 3), and during AD 161-686 (uplift event 4), although uplift events 3 and 4 are identified only at Kouzushima. The minimum amount of uplift was estimated to be 0.4-0.9 m in uplift event 1, 2.4-2.7 m in uplift event 2, 3.6 m in uplift event 3, and 3.3-8.1 m in uplift event 4. These events could have been caused by volcanic activity or strong earthquakes. There also remains the possibility that uplift event 2 was caused by the AD 1498 Meio earthquake; in contrast to the previous interpretation, the ages of uplift events are significantly older than the earthquake, based on conventional (non-AMS) methods.

  13. Evidence for Tectonism Based on Differential Uplift of the Falmouth Formation of Jamaica (United States)

    Skrivanek, A.; Dutton, A.; Stemann, T.; Vyverberg, K.; Mitrovica, J. X.


    We investigate the relative influence of sea-level change and tectonic displacement on the elevations of exposed reef deposits along the coastline of Jamaica. Previous studies disagree about whether or not the northern coastline has been tectonically stable and can be used to infer past sea-level position during the Last Interglacial. We surveyed the maximum elevation of fossil reefs within the Late Pleistocene Falmouth Formation at nine northern and southern sites, and found that peak elevations of this unit vary by several meters between sites. Analysis of exposed reef facies indicates that this observation cannot be entirely explained by variations in reef topography. To estimate the magnitude of tectonic displacement between sites, we combined detailed survey measurements with paleowater depths inferred from uppermost reef facies. The inferred maximum elevation of past sea level position declines by at least 14 meters from Oracabessa to Rio Bueno Harbour, and indicates a clear east-west gradient in uplift along the northern coastline. Maximum Falmouth Formation elevations in the south are lower than those in the north and suggest a pattern of subsidence since its deposition assuming that the uppermost facies are contemporaneous between these two locations. To estimate absolute rates of vertical tectonic displacement since the Last Interglacial, we combined the reconstructed relative sea level position from the elevations and paleowater depth estimates with predictions of peak sea level that account for local glacial isostatic adjustment and the fingerprint of meltwater signals. The observed east-west trend in uplift across the north coast is consistent with the expected sense of tectonic displacement based on the proximity of eastern sites to the inverted Wagwater belt and seismically active Blue Mountain restraining bend. Uplift in the north and subsidence in the south since the Last Interglacial is consistent with tectonic patterns initiated in the Miocene.

  14. Alpine glacial topography and the rate of rock column uplift

    DEFF Research Database (Denmark)

    Pedersen, Vivi Kathrine; Egholm, D.L.; Nielsen, S.B.


    The present study investigates the influence of alpine glacial erosion on the morphology and relief distribution of mountain regions associated with varying rock column uplift rates. We take a global approach and analyse the surface area distribution of all mountain regions affected by glacial er...

  15. Deep mantle forces and the uplift of the Colorado Plateau

    Energy Technology Data Exchange (ETDEWEB)

    Moucha, R; Forte, A M; Rowley, D B; Mitrovica, J X; Simmons, N A; Grand, S P


    Since the advent of plate tectonics, it has been speculated that the northern extension of the East Pacific Rise, specifically its mantle source, has been over-ridden by the North American Plate in the last 30 Myrs. Consequently, it has also been postulated that the opening of the Gulf of California, the extension in the Basin and Range province, and the uplift of the Colorado Plateau are the resulting continental expressions of the over-ridden mantle source of the East Pacific Rise. However, only qualitative models based solely on surface observations and heuristic, simplified conceptions of mantle convection have been used in support or against this hypothesis. We introduce a quantitative model of mantle convection that reconstructs the detailed motion of a warm mantle upwelling over the last 30 Myrs and its relative advance towards the interior of the southwestern USA. The onset and evolution of the crustal uplift in the central Basin and Range province and the Colorado Plateau is determined by tracking the topographic swell due to this mantle upwelling through time. We show that (1) the extension and magmatism in the central Basin and Range province between 25 and 10 Ma coincides with the reconstructed past position of this focused upwelling, and (2) the southwestern portion of the Colorado Plateau experienced significant uplift between 10 Ma and 5 Ma that progressed towards the northeastern portion of the plateau. These uplift estimates are consistent with a young, ca. 6 Ma, Grand Canyon model and the recent commencement of mafic magmatism.

  16. Study of Megabreccia in Ritchey Crater Central Uplift, Mars (United States)

    DING, N.; Bray, V. J.; McEwen, A. S.; Mattson, S.; Okubo, C. H.; Chojnacki, M.; Tornabene, L. L.


    Ritchey Crater (28.8°S, 309°E) is a 79 km diameter complex crater, which is near the boundary between Hesperian ridged plains and Noachian highland terrain units on Mars [1]. The central uplift of Ritchey crater is ~20 km wide. High Resolution Imaging Science Experiment (HiRISE) images of the peak reveal fractured massive bedrock and megabreccia [c.f. 2] with large clasts that appear to have been raised from depth. The stratigraphic uplift in a crater of this size is ~7.7 km [3], comparable to the depth of exposures in Coprates Chasm. Compact Reconnaissance imaging Spectrometer for Mars (CRISM) spectral parameter maps reveal low-calcium pyroxene, olivine, and hydrated silicate clays such as illite. We mapped the Ritchey crater central uplift into ten units[4]. Three types of megabreccia units were identified in this area named by (1)Megabreccia Clast-rich(MC), (2) Buried MegaBreccia(BM) and (3) Megabreccia with Relief(MR). There may be a fourth category with very large blocks(300m) of bedrock. MC is draped over the central uplift and we interpret it as a clast-rich and perhaps melt-rich, impactite produced by the Ritchey impact event. BM is found in small well-consolidated and exposures beneath low calcium pyroxene and olivine-rich massive bedrock. We detect MR distributed within or close to the central cavity of the uplift. MR clasts are more resisitant to weathering than the matrix. Its central location suggests that it could be the deepest and oldest material exposed in the central uplift. We are analyzing the clast size, composition, and stratagraphic arrangement of MR to determine the source of the megabreccia. Ritchey crater is superposed on an older crater of about the same size and its central uplift lies over the destroyed rim of the older crater. This juxtaposition may contribute to the large amount of megabreccia exposure in Ritchey. MR could also represent the exposure of a regionally widespread megabreccia layer due to the Argyre basin to the

  17. The impact of late Cenozoic uplift and erosion on hydrocarbon exploration: offshore Norway and some other uplifted basins (United States)

    Doré, A. G.; Jensen, L. N.


    Uplift and erosion of sedimentary basins can have a wide range of effects, both positive and negative, on hydrocarbon prospectivity. These phenomena are discussed with special reference to the Norwegian Continental Shelf. Late Cenozoic uplift and erosion have affected large expanses of the shelf, and in particular the Barents Sea. Up to 3000 m of sedimentary overburden have been removed from the Barents shelf, and this process is widely held to be responsible for disappointing results in petroleum exploration. Negative effects identified include spillage of hydrocarbons from accumulations, expansion of gas and evacuation of structures, potential for seal failure and cooling of source rocks. We argue, however, that these aspects have been overstated based on a limited database. Many of the world's hydrocarbon basins (and most of the world's petroleum reserves) lie on land. Most of these basins must have been recently uplifted in order to be above sea level today. Using some of these examples, we show that in other areas with a similar magnitude of uplift and erosion to the Barents Sea sealing capacity (particularly that of evaporites) has been preserved. Hydrocarbon systems have remained intact despite phase changes and redistribution of hydrocarbons. Several enhancing effects of the uplift are documented, including the development of fracture permeability in reservoirs, the remigration of hydrocarbons to shallower subsurface levels and the exsolution of light oil (retrograde condensate). Looking to a future in which natural gas may have increased value, potential exists in uplifted basins such as the Barents Sea for vast volumes of methane formed by exsolution from formation brines. We stress the importance of studying such worldwide analogues in order to throw new light on Norwegian shelf problems. Attention is drawn to some striking similarities between the hydrocarbon systems of the Western Canada Basin and those of the Barents Sea. Examination of the massive

  18. Seismicity and neotectonic uplift in the Augrabies Falls National Park, Namaqualand, Northern Cape, South Africa

    Directory of Open Access Journals (Sweden)

    Kakaba Madi


    Full Text Available Abstract Gneissic rocks in the Augrabies Falls National Park are part of the Proterozoic Namaqua-Natal mobile belt. Finding neotectonic evidence in old terranes is always not an easy task. In South Africa, the mid-Miocene is believed to be the beginning of neotectonics. This study investigated the occurrence and recurrence of earthquake activity, occurrence of faulting, jointing, uplift, and potholes in the gneisses cropping out around the Augrabies Falls area that may account for neotectonics. A historic seismic event obtained from the United States Geological Survey (USGS, and seismic epicenters downloaded in October 2015 from IRIS earthquake browser and overlaid on a satellite image with digitised faults and lineaments, indicates that the area is seismically active and is a zone of seismic risk. Potholes occurring today on a dry surface at approximately 613 m above sea level are a direct consequence of the Griqualand-Transvaal neotectonic uplift, which generated a major fault along which water flows continuously. It is concluded that the Augrabies Falls National Park area is a zone of neotectonics. This zone should not be considered for the storage of nuclear wastes.

  19. Harmonic Structure Predicts the Enjoyment of Uplifting Trance Music. (United States)

    Agres, Kat; Herremans, Dorien; Bigo, Louis; Conklin, Darrell


    An empirical investigation of how local harmonic structures (e.g., chord progressions) contribute to the experience and enjoyment of uplifting trance (UT) music is presented. The connection between rhythmic and percussive elements and resulting trance-like states has been highlighted by musicologists, but no research, to our knowledge, has explored whether repeated harmonic elements influence affective responses in listeners of trance music. Two alternative hypotheses are discussed, the first highlighting the direct relationship between repetition/complexity and enjoyment, and the second based on the theoretical inverted-U relationship described by the Wundt curve. We investigate the connection between harmonic structure and subjective enjoyment through interdisciplinary behavioral and computational methods: First we discuss an experiment in which listeners provided enjoyment ratings for computer-generated UT anthems with varying levels of harmonic repetition and complexity. The anthems were generated using a statistical model trained on a corpus of 100 uplifting trance anthems created for this purpose, and harmonic structure was constrained by imposing particular repetition structures (semiotic patterns defining the order of chords in the sequence) on a professional UT music production template. Second, the relationship between harmonic structure and enjoyment is further explored using two computational approaches, one based on average Information Content, and another that measures average tonal tension between chords. The results of the listening experiment indicate that harmonic repetition does in fact contribute to the enjoyment of uplifting trance music. More compelling evidence was found for the second hypothesis discussed above, however some maximally repetitive structures were also preferred. Both computational models provide evidence for a Wundt-type relationship between complexity and enjoyment. By systematically manipulating the structure of chord

  20. Harmonic Structure Predicts the Enjoyment of Uplifting Trance Music (United States)

    Agres, Kat; Herremans, Dorien; Bigo, Louis; Conklin, Darrell


    An empirical investigation of how local harmonic structures (e.g., chord progressions) contribute to the experience and enjoyment of uplifting trance (UT) music is presented. The connection between rhythmic and percussive elements and resulting trance-like states has been highlighted by musicologists, but no research, to our knowledge, has explored whether repeated harmonic elements influence affective responses in listeners of trance music. Two alternative hypotheses are discussed, the first highlighting the direct relationship between repetition/complexity and enjoyment, and the second based on the theoretical inverted-U relationship described by the Wundt curve. We investigate the connection between harmonic structure and subjective enjoyment through interdisciplinary behavioral and computational methods: First we discuss an experiment in which listeners provided enjoyment ratings for computer-generated UT anthems with varying levels of harmonic repetition and complexity. The anthems were generated using a statistical model trained on a corpus of 100 uplifting trance anthems created for this purpose, and harmonic structure was constrained by imposing particular repetition structures (semiotic patterns defining the order of chords in the sequence) on a professional UT music production template. Second, the relationship between harmonic structure and enjoyment is further explored using two computational approaches, one based on average Information Content, and another that measures average tonal tension between chords. The results of the listening experiment indicate that harmonic repetition does in fact contribute to the enjoyment of uplifting trance music. More compelling evidence was found for the second hypothesis discussed above, however some maximally repetitive structures were also preferred. Both computational models provide evidence for a Wundt-type relationship between complexity and enjoyment. By systematically manipulating the structure of chord

  1. Late Miocene uplift and doming of Madagascar: topographic implications (United States)

    Delaunay, Antoine; Robin, Cecile; Guillocheau, François; Dall'Asta, Massimo; Calves, Gérôme


    Madagascar is an Archean to Neoproterozoic continental crust surrounded by transform, oblique and divergent margins: the oblique Morondava Basin to the west, pounded by the Davie Fracture Zone, and to the north, the divergent Mahajanga (Majunga) Basin connected to the Somali Oceanic Basin. This 1600 km long island is a high axial plateau with elevations from 1200 to 1800m. The top of the plateau corresponds to weathered planation surfaces (etchplains), bounded by more or less high scarps. We here present geological arguments for the age and the timing of the Madagascar Plateau. This analysis is based on a double, coupled analysis of the onshore geomorphology (stepped planation surfaces) and the offshore margin stratigraphy (seismic stratigraphy and wells). The geomorphological analysis is based on a characterization, a mapping and dating of stepped planation surfaces (mantled to stripped etchplains, pediments to pediplains). The dating is based on their geometrical relationships with dated magmatic rocks. The difference of elevation between two planation surfaces (corresponding to local base level) provides a proxy of the uplift. The sequence stratigraphic analysis is based on a biostratigraphic reevaluation of 4 industrial wells (foraminifers and nannofossils on cuttings). Uplift periods are characterized by (1) seaward tiltings of the margins overlain by planar reflectors, (2) forced regression wedges and (3) upstream erosions of older sediments recorded by fauna/flora reworking. (1) During Paleocene to Middle Miocene times (66 to 13 Ma), Madagascar is a quite flat low elevation domain with remnants of an oldest pre-Madagascar Trap (90 Ma) surface. This low relief is highly weathered with growth of numerous lateritic profiles and surrounded by large carbonate platforms with no siliciclastic sands influx. (2) The Late Miocene is the paroxysm of uplift with (1) a tilting of the margin (Morondova), (2) an increase of the siliciclastic sand flux since middle Miocene

  2. Uplift, Feedback, and Buoyancy: Radio Lobe Dynamics in NGC 4472 (United States)

    Gendron-Marsolais, M.; Kraft, R. P.; Bogdan, A.; Hlavacek-Larrondo, J.; Forman, W. R.; Jones, C.; Su, Y.; Nulsen, P.; Randall, S. W.; Roediger, E.


    We present results from deep (380 ks) Chandra observations of the active galactic nucleus (AGN) outburst in the massive early-type galaxy NGC 4472. We detect cavities in the gas coincident with the radio lobes and estimate the eastern and western lobe enthalpy to be (1.1+/- 0.5)× {10}56 erg and (3+/- 1)× {10}56 erg and the average power required to inflate the lobes to be (1.8+/- 0.9)× {10}41 erg s-1 and (6+/- 3)× {10}41 erg s-1, respectively. We also detect enhanced X-ray rims around the radio lobes with sharp surface brightness discontinuities between the shells and the ambient gas. The temperature of the gas in the shells is less than that of the ambient medium, suggesting that they are not AGN-driven shocks but rather gas uplifted from the core by the buoyant rise of the radio bubbles. We estimate the energy required to lift the gas to be up to (1.1+/- 0.3)× {10}56 erg and (3+/- 1)× {10}56 erg for the eastern and western rims, respectively, constituting a significant fraction of the total outburst energy. A more conservative estimate suggests that the gas in the rim was uplifted at a smaller distance, requiring only 20%-25% of this energy. In either case, if a significant fraction of this uplift energy is thermalized via hydrodynamic instabilities or thermal conduction, our results suggest that it could be an important source of heating in cool core clusters and groups. We also find evidence for a central abundance drop in NGC 4472. The iron abundance profile shows that the region along the cavity system has a lower metallicity than the surrounding undisturbed gas, similar to the central region. This also shows that bubbles have lifted low-metallicity gas from the center.

  3. Modulation of erosion rates of uplifting landscapes by long-term climate change: Experimental investigation (United States)

    Moussirou, Bérangé; Bonnet, Stéphane


    Whether climatic variations play a major role, or not, in setting the erosion rate of continental landscapes is key for demonstrating the influence of climate on the tectonic evolution of mountain belts, as expected from analytical, numerical and analog modelling approaches. These models actually demonstrate that any modification in surface erosion rate that would affect significantly the gravitational loading of the continental crust might change its state of stress and consequently its deformation. However field evidences of these interactions has proved challenging to demonstrate unambiguously, the question of the climatic control on erosion efficiency at the geological time-scale being among the most critical issues. Here, we investigate how a change in precipitation influences the erosional dynamics of a landscape on the basis of an experimental approach where we surveyed the erosion by runoff of water of laboratory-scale landscapes that evolved under the combination of uplift and rainfall forcings (e.g. Bonnet and Crave, 2006). The experimental facility used is a modified of a device initially developed in the Geosciences Rennes laboratory and now set up in the Geosciences Environnement Toulouse laboratory. Following early experiments of Bonnet and Crave (2003) where the effect of a sudden drop in precipitation was investigated, we consider here the impact of decreasing rainfall events of finite duration on the erosive response of a landscape forced by a constant uplift (10 mm/h) and initially at steady-state (SS1). We performed several experiments with the same amplitude (from 160 to 60mm/h) but with different duration of rainfall drop (Tp: 0, 60, 300, 500, 700 min). As predicted theoretically and already observed in numerical and experimental modelling studies, a sudden drop of precipitation rate (Tp=0) induced a decrease of the mean erosion rate of the landscape (E), resulting in surface uplift. Then, landscape mean elevation stabilized to a higher value

  4. Uplift, thermal unrest and magma intrusion at Yellowstone caldera. (United States)

    Wicks, Charles W; Thatcher, Wayne; Dzurisin, Daniel; Svarc, Jerry


    The Yellowstone caldera, in the western United States, formed approximately 640,000 years ago when an explosive eruption ejected approximately 1,000 km3 of material. It is the youngest of a series of large calderas that formed during sequential cataclysmic eruptions that began approximately 16 million years ago in eastern Oregon and northern Nevada. The Yellowstone caldera was largely buried by rhyolite lava flows during eruptions that occurred from approximately 150,000 to approximately 70,000 years ago. Since the last eruption, Yellowstone has remained restless, with high seismicity, continuing uplift/subsidence episodes with movements of approximately 70 cm historically to several metres since the Pleistocene epoch, and intense hydrothermal activity. Here we present observations of a new mode of surface deformation in Yellowstone, based on radar interferometry observations from the European Space Agency ERS-2 satellite. We infer that the observed pattern of uplift and subsidence results from variations in the movement of molten basalt into and out of the Yellowstone volcanic system.

  5. Uplift, thermal unrest and magma intrusion at Yellowstone caldera (United States)

    Wicks, Charles W.; Thatcher, Wayne; Dzurisin, Daniel; Svarc, Jerry


    The Yellowstone caldera, in the western United States, formed ~640,000years ago when an explosive eruption ejected ~1,000km3 of material. It is the youngest of a series of large calderas that formed during sequential cataclysmic eruptions that began ~16 million years ago in eastern Oregon and northern Nevada. The Yellowstone caldera was largely buried by rhyolite lava flows during eruptions that occurred from ~150,000 to ~70,000years ago. Since the last eruption, Yellowstone has remained restless, with high seismicity, continuing uplift/subsidence episodes with movements of ~70cm historically to several metres since the Pleistocene epoch, and intense hydrothermal activity. Here we present observations of a new mode of surface deformation in Yellowstone, based on radar interferometry observations from the European Space Agency ERS-2 satellite. We infer that the observed pattern of uplift and subsidence results from variations in the movement of molten basalt into and out of the Yellowstone volcanic system.

  6. Uplift of the Owen Ridge and giant landslides (NW Indian Ocean) (United States)

    Rodriguez, Mathieu; Fournier, Marc; Chamot-Rooke, Nicolas; Huchon, Philippe


    The present-day India-Arabia plate boundary in the NW Indian Ocean is located along a 800 km long dextral strike slip fault system, known as the Owen Fracture Zone (OFZ). This fault system connects the spreading centres of the Sheba and Carlsberg ridge system to the Makran subduction zone. The OFZ is bounded to the west by the Owen Ridge, a series of seamounts and topographic highs which isolate the Owen Basin from Indus turbiditic supply. In March 2009, this area has been surveyed by the R/V Beautemps-Beaupré using a high resolution multibeam echo-sounder and sub-surface seismic profiles to reveal tectonic and sedimentary features related to the OFZ. To the south, the OFZ crosscuts the southern portion of the Owen Ridge and offsets it dextrally over 12 km. The southern portion of the Owen Ridge consists in a 300 km-long, 2000 m-high, N-S trending relief. This ridge portion is asymmetric with a steep (15°) east-facing scarp associated with the OFZ and a gentle western slope corresponding to sedimentary beds tilted 3° to the west. Our morphometric analysis provides a detailed map of the Southern Owen Ridge (including the OFZ) and reveals giant landslides on its western flank. The destabilization involves a large variety of mass wasting processes, such as slump, slide, rockfall, debris flows and crown cracks. The volume of all the removed material, estimated at 135 km3, has been drained off westwards in the Owen Basin. In the light of our new data, we re-analyse previous seismic profiles and cores collected during the ODP LEG 117. These data suggest that several episodes of destabilization occurred during the uplift of the Southern Owen Ridge which began 20 Myr ago. Giant landslides could have been triggered by earthquakes along the OFZ, and/or by the uplift motion, and could have provoked tsunamis, affecting the East coast of Oman. The uplift is thought to be of transpressive origin and consistent with early Miocene compressive structures observed inland in the

  7. Biostratigraphic evidence for dramatic Holocene uplift of Robinson Crusoe Island, Juan Fernández Ridge, SE Pacific Ocean (United States)

    Sepúlveda, P.; Le Roux, J. P.; Lara, L. E.; Orozco, G.; Astudillo, V.


    Hotspot oceanic islands typically experience subsidence due to several processes related to migration of the oceanic plate away from the mantle plume and surface flexural loading. However, many other processes can interrupt subsidence, some of which may be associated with catastrophic events. A study of the biostratigraphy and sedimentology of Holocene deposits on Robinson Crusoe Island (RCI) on the Juan Fernández Ridge (JFR) indicated that dramatic uplift has occurred since 8000 years BP, at a rate of about 8.5mm yr-1. This is evidenced by supratidal flats with tepee structures and sand layers containing marine gastropods (mostly Nerita sp.) that are now exposed ca. 70 m a.s.l. The active hotspot is located 280 km further west and the last volcanic activity on RCI occurred at ca. 800 000 years BP. Long-term subsidence is evidenced by deep submerged marine abrasion terraces at RCI. As no direct evidence was found for the existence of a compensating bulge generated by the present hotspot upon which RCI would be situated, it must be concluded that subsidence in the wake of the mantle plume beneath the migrating plate was interrupted by very rapid uplift, but on a scale that did not fully compensate for the previous subsidence. This can be attributed to large-scale landslides followed by isostatic rebound, although this is only vaguely reflected in the low-resolution bathymetry of the area. To determine if this mechanism produced the uplift, a detailed bathymetric survey of the area will be required. If such a survey confirms this hypothesis, it may have implications for the short-term dynamics of vertical variations of oceanic edifices and their related effects on ecosystems and human population.

  8. East Antarctic rifting triggers uplift of the Gamburtsev Mountains. (United States)

    Ferraccioli, Fausto; Finn, Carol A; Jordan, Tom A; Bell, Robin E; Anderson, Lester M; Damaske, Detlef


    The Gamburtsev Subglacial Mountains are the least understood tectonic feature on Earth, because they are completely hidden beneath the East Antarctic Ice Sheet. Their high elevation and youthful Alpine topography, combined with their location on the East Antarctic craton, creates a paradox that has puzzled researchers since the mountains were discovered in 1958. The preservation of Alpine topography in the Gamburtsevs may reflect extremely low long-term erosion rates beneath the ice sheet, but the mountains' origin remains problematic. Here we present the first comprehensive view of the crustal architecture and uplift mechanisms for the Gamburtsevs, derived from radar, gravity and magnetic data. The geophysical data define a 2,500-km-long rift system in East Antarctica surrounding the Gamburtsevs, and a thick crustal root beneath the range. We propose that the root formed during the Proterozoic assembly of interior East Antarctica (possibly about 1 Gyr ago), was preserved as in some old orogens and was rejuvenated during much later Permian (roughly 250 Myr ago) and Cretaceous (roughly 100 Myr ago) rifting. Much like East Africa, the interior of East Antarctica is a mosaic of Precambrian provinces affected by rifting processes. Our models show that the combination of rift-flank uplift, root buoyancy and the isostatic response to fluvial and glacial erosion explains the high elevation and relief of the Gamburtsevs. The evolution of the Gamburtsevs demonstrates that rifting and preserved orogenic roots can produce broad regions of high topography in continental interiors without significantly modifying the underlying Precambrian lithosphere. © 2011 Macmillan Publishers Limited. All rights reserved

  9. GPS Imaging of vertical land motion in California and Nevada: Implications for Sierra Nevada uplift (United States)

    Hammond, William C.; Blewitt, Geoffrey; Kreemer, Corné


    We introduce Global Positioning System (GPS) Imaging, a new technique for robust estimation of the vertical velocity field of the Earth's surface, and apply it to the Sierra Nevada Mountain range in the western United States. Starting with vertical position time series from Global Positioning System (GPS) stations, we first estimate vertical velocities using the MIDAS robust trend estimator, which is insensitive to undocumented steps, outliers, seasonality, and heteroscedasticity. Using the Delaunay triangulation of station locations, we then apply a weighted median spatial filter to remove velocity outliers and enhance signals common to multiple stations. Finally, we interpolate the data using weighted median estimation on a grid. The resulting velocity field is temporally and spatially robust and edges in the field remain sharp. Results from data spanning 5-20 years show that the Sierra Nevada is the most rapid and extensive uplift feature in the western United States, rising up to 2 mm/yr along most of the range. The uplift is juxtaposed against domains of subsidence attributable to groundwater withdrawal in California's Central Valley. The uplift boundary is consistently stationary, although uplift is faster over the 2011-2016 period of drought. Uplift patterns are consistent with groundwater extraction and concomitant elastic bedrock uplift, plus slower background tectonic uplift. A discontinuity in the velocity field across the southeastern edge of the Sierra Nevada reveals a contrast in lithospheric strength, suggesting a relationship between late Cenozoic uplift of the southern Sierra Nevada and evolution of the southern Walker Lane.

  10. The Prediction Model of Dam Uplift Pressure Based on Random Forest (United States)

    Li, Xing; Su, Huaizhi; Hu, Jiang


    The prediction of the dam uplift pressure is of great significance in the dam safety monitoring. Based on the comprehensive consideration of various factors, 18 parameters are selected as the main factors affecting the prediction of uplift pressure, use the actual monitoring data of uplift pressure as the evaluation factors for the prediction model, based on the random forest algorithm and support vector machine to build the dam uplift pressure prediction model to predict the uplift pressure of the dam, and the predict performance of the two models were compared and analyzed. At the same time, based on the established random forest prediction model, the significance of each factor is analyzed, and the importance of each factor of the prediction model is calculated by the importance function. Results showed that: (1) RF prediction model can quickly and accurately predict the uplift pressure value according to the influence factors, the average prediction accuracy is above 96%, compared with the support vector machine (SVM) model, random forest model has better robustness, better prediction precision and faster convergence speed, and the random forest model is more robust to missing data and unbalanced data. (2) The effect of water level on uplift pressure is the largest, and the influence of rainfall on the uplift pressure is the smallest compared with other factors.

  11. GPS Imaging of vertical land motion in California and Nevada: Implications for Sierra Nevada uplift. (United States)

    Hammond, William C; Blewitt, Geoffrey; Kreemer, Corné


    We introduce Global Positioning System (GPS) Imaging, a new technique for robust estimation of the vertical velocity field of the Earth's surface, and apply it to the Sierra Nevada Mountain range in the western United States. Starting with vertical position time series from Global Positioning System (GPS) stations, we first estimate vertical velocities using the MIDAS robust trend estimator, which is insensitive to undocumented steps, outliers, seasonality, and heteroscedasticity. Using the Delaunay triangulation of station locations, we then apply a weighted median spatial filter to remove velocity outliers and enhance signals common to multiple stations. Finally, we interpolate the data using weighted median estimation on a grid. The resulting velocity field is temporally and spatially robust and edges in the field remain sharp. Results from data spanning 5-20 years show that the Sierra Nevada is the most rapid and extensive uplift feature in the western United States, rising up to 2 mm/yr along most of the range. The uplift is juxtaposed against domains of subsidence attributable to groundwater withdrawal in California's Central Valley. The uplift boundary is consistently stationary, although uplift is faster over the 2011-2016 period of drought. Uplift patterns are consistent with groundwater extraction and concomitant elastic bedrock uplift, plus slower background tectonic uplift. A discontinuity in the velocity field across the southeastern edge of the Sierra Nevada reveals a contrast in lithospheric strength, suggesting a relationship between late Cenozoic uplift of the southern Sierra Nevada and evolution of the southern Walker Lane.

  12. Episodic swell growth inferred from variable uplift of the Cape Verde hotspot islands (United States)

    Ramalho, R.; Helffrich, G.; Cosca, M.; Vance, D.; Hoffmann, D.; Schmidt, D.N.


    On the Beagle voyage, Charles Darwin first noted the creation and subsidence of ocean islands, establishing in geology's infancy that island freeboard changes with time. Hotspot ocean islands have an obvious mechanism for freeboard change through the growth of the bathymetric anomaly, or swell, on which the islands rest. Models for swell development indicate that flexural, thermal or dynamic pressure contributions, as well as spreading of melt residue from the hotspot, can all contribute to island uplift. Here we test various models for swell development using the uplift histories for the islands of the Cape Verde hotspot, derived from isotopic dating of marine terraces and subaerial to submarine lava-flow morphologies. The island uplift histories, in conjunction with inter-island spacing, uplift rate and timing differences, rule out flexural, thermal or dynamic pressure contributions. We also find that uplift cannot be reconciled with models that advocate the spreading of melt residue in swell development unless swell growth is episodic. Instead, we infer from the uplift histories that two processes have acted to raise the islands during the past 6 Myr. During an initial phase, mantle processes acted to build the swell. Subsequently, magmatic intrusions at the island edifice caused 350 m of local uplift at the scale of individual islands. Finally, swell-wide uplift contributed a further 100 m of surface rise.

  13. Elastic uplift in southeast Greenland due to rapid ice mass loss

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Van dam, Tonie; Hamilton, Gordon S.


    , calculated from sequential digital elevation models, contributes about 16 mm of the observed uplift, with an additional 5 mm from volume loss of Kangerdlugssuaq Glacier. The remaining uplift signal is attributed to significant melt-induced ice volume loss from the ice sheet margin along the southeast coast......The rapid unloading of ice from the southeastern sector of the Greenland ice sheet between 2001 and 2006 caused an elastic uplift of 35 mm at a GPS site in Kulusuk. Most of the uplift results from ice dynamic-induced volume losses on two nearby outlet glaciers. Volume loss from Helheim Glacier...... between 62N and 66N. Citation: Khan, S. A., J. Wahr, L. A. Stearns, G. S. Hamilton, T. van Dam, K. M. Larson, and O. Francis (2007), Elastic uplift in southeast Greenland due to rapid ice mass loss....

  14. Uplift rates of marine terraces as a constraint on fault-propagation fold kinematics: Examples from the Hawkswood and Kate anticlines, North Canterbury, New Zealand (United States)

    Oakley, David O. S.; Fisher, Donald M.; Gardner, Thomas W.; Stewart, Mary Kate


    Marine terraces on growing fault-propagation folds provide valuable insight into the relationship between fold kinematics and uplift rates, providing a means to distinguish among otherwise non-unique kinematic model solutions. Here, we investigate this relationship at two locations in North Canterbury, New Zealand: the Kate anticline and Haumuri Bluff, at the northern end of the Hawkswood anticline. At both locations, we calculate uplift rates of previously dated marine terraces, using DGPS surveys to estimate terrace inner edge elevations. We then use Markov chain Monte Carlo methods to fit fault-propagation fold kinematic models to structural geologic data, and we incorporate marine terrace uplift into the models as an additional constraint. At Haumuri Bluff, we find that marine terraces, when restored to originally horizontal surfaces, can help to eliminate certain trishear models that would fit the geologic data alone. At Kate anticline, we compare uplift rates at different structural positions and find that the spatial pattern of uplift rates is more consistent with trishear than with a parallel-fault propagation fold kink-band model. Finally, we use our model results to compute new estimates for fault slip rates ( 1-2 m/ka at Kate anticline and 1-4 m/ka at Haumuri Bluff) and ages of the folds ( 1 Ma), which are consistent with previous estimates for the onset of folding in this region. These results are consistent with previous work on the age of onset of folding in this region, provide revised estimates of fault slip rates necessary to understand the seismic hazard posed by these faults, and demonstrate the value of incorporating marine terraces in inverse fold kinematic models as a means to distinguish among non-unique solutions.

  15. Investigating Rapid Uplift and Subsidence Near Norris, Yellowstone, During 2013-2014 (United States)

    Stovall, W. K.; Cervelli, P. F.; Shelly, D. R.


    Although Yellowstone's last magmatic eruption occurred about 70,000 years ago, hydrothermal explosions, earthquakes, and ground deformation still occur as testament to ongoing volcanic and tectonic processes. Since the late 1990s, a network of continuously recording Global Positioning System (GPS) receivers has recorded uplift and subsidence of the caldera and northwest caldera margin near Norris Geyser Basin. Previous deformation episodes have shown opposing vertical motion at the two sites, which has been attributed to temporal variations in magmatic fluid flux from the caldera laterally through the Norris-Mammoth fault corridor that intersects the caldera's northwest margin (Dzurisin et al., 2012; Wicks et al., 2006). These episodes have exhibited gradual changes, transitioning from uplift to subsidence (and vice versa) over weeks to months. Large earthquake swarms accompanied transitions from caldera uplift to subsidence in 1985 and 2010. Recent deformation in Yellowstone differs from previously observed episodes. In the latter half of 2013, uplift began around Norris, and by January of 2014 it reached rates of over 15 cm/yr. Also at the start of 2014, caldera deformation shifted from approximately 4 years of slow subsidence to slow uplift. On March 30, 2014, a M4.8 earthquake, the largest in Yellowstone since 1980, occurred northwest of Norris Geyser Basin near the center of uplift. Shortly after the event, deformation near Norris abruptly reversed to rapid subsidence (over 20 cm/yr). Caldera uplift began to accelerate around the same time. Thus, uplift can occur simultaneously in both the caldera and the Norris area, and dramatic reversals from rapid uplift to rapid subsidence can occur within a matter of days. While the complexity of the deformation defies a simple explanation, we hypothesize that the rapid transition from uplift to subsidence at Norris may indicate that the M4.8 earthquake opened a pathway for fluid migration away from Norris and allowed an

  16. Dynamic Topography during Flat Subduction: Subsidence or Uplift? (United States)

    Davila, F. M.; Lithgow-Bertelloni, C. R.


    Since the first studies on dynamic topography and basin evolution, low-dipping subduction has been related to intracontinental, long-wavelength and high-amplitude subsidence, whereas retreating to normal subduction systems to uplift. This was proposed to explain the Cretaceous-early Cenozoic topographic evolution of the western US. However, modern flat-slab and slab-retreating segments of South America do not record such a subsidence and uplift patterns. For example, the flat slab of Peru at ˜10°SL, related to the subduction of the Nazca Ridge, underlies an elevated promontory known as the Fitzcarrald Arch. The Argentine flat-slab at ˜31°SL associated to the subduction of the Juan Fernandez Ridge underlies a high-elevated intermontane system known as the Pampean broken foreland. Both upwarping features are younger than 7 Ma and contemporaneous with the arrival of flat subduction to these segments. In order to shed light into this controversy, we calculate dynamic topography along the Andean flat-slab segments using the Hager and O'Connell (1981) instantaneous flow formulation, an accurate reconstruction of the slab geometry along the central Andes and a density contrast between the flat slabs and the country mantle close to zero (△δ≈0) in order to simulate a buoyant oceanic lithosphere. We demonstrate that dynamic subsidence develops only at the leading edge of flat subduction, where the slabs plunge >30°, whereas the flatter slabs reproduce minor or no dynamic topography signals. These results agree with geological and geophysical proxies. Along the Argentine Plains, the account for a accumulated relief of ˜200 m, which might be considered as an "observed dynamic subsidence" signal (given that no tectonic activity has been recorded in this region since the Cretaceous to explain this surface topography). This gives a ˜0.03 mm/yr dynamic subsidence rate that are curiously similar to the exhumations estimated by low-temperature thermochronology along the

  17. Uplift of the Colorado Plateau due to lithosphere attenuation during Laramide low-angle subduction (United States)

    Spencer, J.E.


    The Colorado Plateau is blanketed by Phanerozoic marine and nonmarine strata as young as Cretaceous that are now exposed at elevations of about 2 km. Crustal thickening due to magmatism and horizontal crustal shortening was far less than necessary to cause this uplift, which is commonly attributed to the consequences of mantle lithosphere thinning and heating. The Colorado Plateau and the midcontinent region around Iowa consist of Precambrian bedrock overlain by a similar amount of Paleozoic platformal strata, and thus both regions once had similar lithospheric buoyancy. Mesozoic sedimentation increased the crustal thickness and lithospheric buoyancy of the Colorado Plateau relative to the midcontinent region. Backstripping calculations yield elevation without these sediments and lead to a calculated elevation difference between the two areas of about 1200 m, which represents unexplained plateau uplift. Review of constraints on uplift timing finds little support for a late Cenozoic uplift age and allows early to middle Cenozoic uplift, which is consistent with uplift mechanisms related to low-angle subduction that ended in the middle Cenozoic. Finite element heat flow calculations of low-angle subduction and lithosphere attenuation, using a range of initial lithosphere thicknesses and degree of attenuation, indicate that required uplift can result from tectonic removal of about 120 km of mantle lithosphere from an initially 200-km-thick lithosphere. This allows for partial preservation of North American mantle lithosphere with its distinctive isotopic signature in some late Cenozoic volcanic rocks and is consistent with normal Pn velocities in the uppermost mantle beneath the plateau.

  18. Regional cenozoic uplift and subsidence events in the southeastern North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Jordt, H.


    The Paleocene topography of the Fennoscandian Shield is indicated by outbuilding towards the Central Trough and the Ringkoebing-Fyn High. From Eocene until Pliocene time three events of relative vertical movements are indicated by changes in outbuilding directions and reflection termination patterns in the central North Sea. The firs event of uplift was in the Eocene and resulted in relative uplift of the Mid North Sea High and contemporary subsidence east of it, indicated by a change in outbuilding from north to west. A second event of uplift is indicated to the north of the study area at the Eocene-Oligocene boundary by renewed southward outbuilding in the Norwegian-Danish Basin. In Miocene until Early Pliocene time a relatively stationary, almost east-west striking, basin margin was probably located to the north along the Tornquist Zone as indicated by the continued outbuilding towards the Ringkoebing-Fyn High. A third event of relative uplift is indicated east of the study area by changes in the Pliocene outbuilding pattern. After the first event of uplift it appears that the deepest parts of the Eocene North Sea Basin was located more easterly than the deepest part are today. Apparently the two latest uplift events north and east of the study area were related to movements of, or along the Tornquist Zone or to regional uplift of the Fennoscandian Shield finally resulting in the present-day configuration of the North Sea. (au) 11 refs.

  19. Emergence and evolution of Santa Maria Island (Azores)—The conundrum of uplifted islands revisited (United States)

    Ramalho, Ricardo; Helffrich, George; Madeira, Jose; Cosca, Michael A.; Thomas, Christine; Quartau, Rui; Hipolito, Ana; Rovere, Alessio; Hearty, Paul; Avila, Sergio


    The growth and decay of ocean-island volcanoes are intrinsically linked to vertical movements. While the causes for subsidence are better understood, uplift mechanisms remain enigmatic. Santa Maria Island in the Azores Archipelago is an ocean-island volcano resting on top of young lithosphere, barely 480 km away from the Mid-Atlantic Ridge. Like most other Azorean islands, Santa Maria should be experiencing subsidence. Yet, several features indicate an uplift trend instead. In this paper, we reconstruct the evolutionary history of Santa Maria with respect to the timing and magnitude of its vertical movements, using detailed field work and 40Ar/39Ar geochronology. Our investigations revealed a complex evolutionary history spanning ∼6 m.y., with subsidence up to ca. 3.5 Ma followed by uplift extending to the present day. The fact that an island located in young lithosphere experienced a pronounced uplift trend is remarkable and raises important questions concerning possible uplift mechanisms. Localized uplift in response to the tectonic regime affecting the southeastern tip of the Azores Plateau is unlikely, since the area is under transtension. Our analysis shows that the only viable mechanism able to explain the uplift is crustal thickening by basal intrusions, suggesting that intrusive processes play a significant role even on islands standing on young lithosphere, such as in the Azores.

  20. SURVEY

    DEFF Research Database (Denmark)

    SURVEY er en udbredt metode og benyttes inden for bl.a. samfundsvidenskab, humaniora, psykologi og sundhedsforskning. Også uden for forskningsverdenen er der mange organisationer som f.eks. konsulentfirmaer og offentlige institutioner samt marketingsafdelinger i private virksomheder, der arbejder...

  1. Extracting Uplift Rate Histories From Longitudinal River Profiles: Examples From North America and Africa (United States)

    Roberts, Gareth G.; White, Nicky; Paul, Jonathan


    The physiography of the Earth's surface is a manifestation of vertical motions, erosion, and deposition of sediment. We show that a history of uplift rate of the continents during the last ~ 100 million years can be determined by jointly inverting the longitudinal profiles of rivers. We assume that the shape of a river profile is controlled by the history of uplift rate and moderated by the erosional process. We have parameterized fluvial erosion using a nonlinear advective-diffusive formulation. A river profile per se contains no information about the erosional timescale; values of erosional parameters must be calibrated. If either vertical incision rate or knickzone retreat rate is known independently, for example when palaeo-river profiles are preserved, we can calibrate the erosional model directly. Independent spot measurements of uplift offer another way to calibrate a regional model. In our inverse model, uplift rate is allowed to vary smoothly as a function of space and time, and upstream drainage area is invariant. Using this inverse methodology, we show that there exist time-correlative commonalities in the shapes of river profiles draining uplifted regions. We find that the rate at which knickzones propagate upstream is linearly dependent on slope in nearly all cases (i.e. n = 1 in the detachment-limited erosional model for ~ 600 North American and African rivers). The exponent on upstream drainage, m, which controls knickzone retreat rate, is typically Zambezi rivers and their major tributaries indicates that domal swells in Africa have experienced a staged uplift history. The West African margin has experienced at least two phases of uplift during the last 30 Ma. Uplift in Afar began ~ 35 Ma. The Hoggar and Tibesti swells, in central North Africa, have an older history of uplift. These results are consistent with a staged magmatic history, delivery of sediment to the continental margins and stratigraphic observations, which suggest that the African

  2. Responses of dune plant communities to continental uplift from a major earthquake: sudden releases from coastal squeeze. (United States)

    Rodil, Iván F; Jaramillo, Eduardo; Hubbard, David M; Dugan, Jenifer E; Melnick, Daniel; Velasquez, Carlos


    Vegetated dunes are recognized as important natural barriers that shelter inland ecosystems and coastlines suffering daily erosive impacts of the sea and extreme events, such as tsunamis. However, societal responses to erosion and shoreline retreat often result in man-made coastal defence structures that cover part of the intertidal and upper shore zones causing coastal squeeze and habitat loss, especially for upper shore biota, such as dune plants. Coseismic uplift of up to 2.0 m on the Peninsula de Arauco (South central Chile, ca. 37.5º S) caused by the 2010 Maule earthquake drastically modified the coastal landscape, including major increases in the width of uplifted beaches and the immediate conversion of mid to low sandy intertidal habitat to supralittoral sandy habitat above the reach of average tides and waves. To investigate the early stage responses in species richness, cover and across-shore distribution of the hitherto absent dune plants, we surveyed two formerly intertidal armoured sites and a nearby intertidal unarmoured site on a sandy beach located on the uplifted coast of Llico (Peninsula de Arauco) over two years. Almost 2 years after the 2010 earthquake, dune plants began to recruit, then rapidly grew and produced dune hummocks in the new upper beach habitats created by uplift at the three sites. Initial vegetation responses were very similar among sites. However, over the course of the study, the emerging vegetated dunes of the armoured sites suffered a slowdown in the development of the spatial distribution process, and remained impoverished in species richness and cover compared to the unarmoured site. Our results suggest that when released from the effects of coastal squeeze, vegetated dunes can recover without restoration actions. However, subsequent human activities and management of newly created beach and dune habitats can significantly alter the trajectory of vegetated dune development. Management that integrates the effects of natural

  3. Uplift in the Fiordland region, New Zealand: implications for incipient subduction. (United States)

    House, M A; Gurnis, M; Kamp, P J J; Sutherland, R


    Low-temperature thermochronometry reveals regional Late Cenozoic denudation in Fiordland, New Zealand, consistent with geodynamic models showing uplift of the overriding plate during incipient subduction. The data show a northward progression of exhumation in response to northward migration of the initiation of subduction. The locus of most recent uplift coincides with a large positive Bouguer gravity anomaly within Fiordland. Thermochronometrically deduced crustal thinning, anomalous gravity, and estimates of surface uplift are all consistent with approximately 2 kilometers of dynamic support. This amount of dynamic support is in accord with geodynamic predictions, suggesting that we have dated the initiation of subduction adjacent to Fiordland.

  4. Centrifuge Testing and Seismic Response Analysis for Uplift Behavior of Spread Foundation Structures on Rock

    Directory of Open Access Journals (Sweden)

    Takuya Suzuki


    Full Text Available The uplift behavior of structures subjected to severe seismic motion has not been clarified. This paper presents experimental and analytical studies conducted for clarifying this problem of spread foundation structures on rock. First, centrifugal loading tests are conducted to determine the uplift behavior of these structures, and the uplift behavior of these structures is confirmed. Then, simulation analyses are performed using a three-dimensional FE model and the accuracy of these analyses is confirmed. A comparison between test and analyses results clarified the important analytical conditions required for maintaining analysis precision and the limit of analysis precision.

  5. Tectonics, Uplift and Surface Processes in the Moroccan Atlas Mountains (United States)

    Teixell, A.; Arboleya, M.; Babault, J.; Teson, E.; Ayarza, P.; Alvarez-Lobato, F.; Owen, L. A.


    The Atlas Mountains of Morocco constitute a natural laboratory for studying interactions between tectonics and surface processes in convergent zones. The tectonic forcing of the system is well understood, where a combination of crustal and mantle processes contributed to surface uplift. A growing database on magnetostratigraphic dating of synorogenic sediments, low-temperature thermochronology and surface exposure dating constrain the relationships between tectonics, erosion, climate and drainage patterns during the late Cenozoic. The Atlas chains derive from the Cenozoic inversion of Triassic-Jurassic rifts in the NW African plate. Topography is high: large areas lie over 2000 m of mean elevation, and summits exceed 4000 m. In spite of high elevation, crustal thickening is modest: tectonic shortening is mean rate of 0.2 mm/a. Moderate erosion in the Atlas prevents to detect Cenozoic apatite fission-track ages except from narrow areas, where ages of 17-25 Ma record exhumation induced by the crustal shortening mechanism. The southern, best preserved foreland basin system of the Atlas Mountains was internally drained until the late Miocene-early Pliocene. The system was then captured or overflowed across mountain massifs that bordered it to the S (Anti-Atlas). External drainage resulted in fluvial incision strongly modulated by climate change on glacial-interglacial timescales, as evidenced by cosmogenic dating of fans and terraces. Incision occurred at rates of 0.3-1 mm/a for the later part of the Quaternary, demonstrating a strong climatic control on sediment transfer and landscape denudation during this epoch.

  6. Multiple uplift phases inferred from the Southwest African Atlantic margin (United States)

    Scheck-Wenderoth, Magdalena; Cacace, Mauro; Dressel, Ingo


    The South Atlantic basins offshore Namibia and South Africa stored more than 10 km thick sedimentary successions that are separated by major unconformities into several sequences. These sedimentary units rest on a thinned continental crust of a magmatic passive margin. Using a 3D forward modelling approach considering flexural compensation of a rheologically differentiated lithosphere in response to sedimentary loading after stretching on one hand and the thermal feed-back between cooling of the stretched lithosphere and insulating sediments on the other hand we derive quantitative estimates on how vertical movements have influenced the margin after stretching. The approach combines the consideration of observations on sediment configuration as well as on crustal thickness (ß-factor) with the process of lithosphere thinning and subsequent thermal re-equilibration. These estimates are conservative estimates as they are based on the preserved sediments only whereas eroded sediments are not considered. Nevertheless, the approach considers thermo-mechanical coupling in 3D and both initial conditions as well as sedimentary history are constrained by observations. Specific effects include the delayed thermal re-equilibration of the thinned lithosphere due to deposition of insulating sediments and the related thermal feedback on lithosphere rheology and therefore on the flexural response to sediment loading. Our results indicate that in addition to predominantly continuous subsidence also phases of uplift have affected the southwestern African margin during the syn-rift and post-rift evolution. The spatio-temporal variation of vertical movements is controlled by the amount of initial thinning of the lithosphere, the variation of rheological characteristics (lithology and temperature) but also by the distribution of sediment supply (loading and thermal insulation).

  7. A late Eocene palynological record of climate change and Tibetan Plateau uplift (Xining Basin, China)

    NARCIS (Netherlands)

    Hoorn, C.; Straathof, J.; Abels, H.A.; Xu, Y.; Utescher, T.; Dupont-Nivet, G.


    Climate models suggest that Asian paleoenvironments, monsoons and continental aridification were primarily governed by tectonic uplift and sea retreat since the Eocene with potential contribution of global climate changes. However, the cause and timing of these paleoenvironmental changes remain

  8. Oroclinal Bending and Mountain Uplift in the Central Andes (United States)

    Mpodozis, C.; Arriagada, C.; Roperch, P.


    The large paleomagnetic database now available for the Central Andes permits a good understanding of the overall spatial and temporal variations of rotations. Mesozoic to Early Paleogene rocks along the forearc of northern Chile (23°-28°S) record significant clockwise rotations (>25°) [Arriagada et al., 2006, Tectonics, doi:10.1029/2005TC001923]. Along the forearc of southern Peru, counterclockwise rotations recorded within flat lying red-beds (Moquegua Formation) increase from about -30° at 17.5°S to - 45° at15.5°S and decrease through time from the late Eocene to the late Oligocene-early Miocene [Roperch et al., 2006, Tectonics, doi:10.1029/2005TC001882]. Recently published thermo-chronological studies show evidence for strong exhumation within Bolivian Eastern Cordillera and the Puna plateau starting in the Eocene while structural studies indicate that the majority of crustal shortening in the Eastern Cordillera occurred during the Eocene-Oligocene, although the final stages of deformation may have continued through the Early Miocene. Rotations in the Peruvian and north Chilean forearc thus occurred at the same time than deformation and exhumation/uplift within the Eastern Cordillera. In contrast Neogene forearc rocks in southern Peru and northern Chile do not show evidences of rotation but low magnitude (10°) counterclockwise rotations are usually found in mid to late Miocene rocks from the northern Altiplano. These Neogene rotations are concomitant with shortening in the Sub-Andean zone and sinistral strike-slip faulting along the eastern edge of the northern Altiplano. We interpret the rotation pattern along the southern Peru and north Chile forearc as a result of strong late Eocene- late Oligocene oroclinal bending of the Central Andes associated with shortening gradients along the Eastern Cordillera associated both with the Abancay deflection and the Arica bend. The amount and spatial distribution of pre-Neogene shortening needed to account for

  9. Late Quaternary river terrace sequences in the eastern Kunlun Range, northern Tibet: A combined record of climatic change and surface uplift (United States)

    Wang, An; Smith, Jacqueline A.; Wang, Guocan; Zhang, Kexin; Xiang, Shuyuan; Liu, Demin


    The Kunlun Range, a reactivated orogenic belt, constitutes the northern margin of the Tibetan Plateau. The extreme relief and major landforms of the Kunlun Range are a product of late Cenozoic tectonics and erosion. However, well-developed late Quaternary terraces that occur along the northern slope of the Kunlun Range probably resulted from climatic change rather than surface uplift. The terrace sequences formed in thick Quaternary valley fills and have total incision depths of 50-60 m. Optically stimulated luminescence dating was employed to place time controls on the valley fills and associated terraces. Dating results suggest that periods of significant aggradation were synchronous between different rivers and correspond to the last glacial stage. The abrupt change from aggradation to incision occurred between 21.9 ± 2.7 and 16 ± 2.2 ka, coincident with the last glacial-interglacial transition. Additional terraces developed during the late glacial period and early to middle Holocene. Based on a broader set of chronological data in northern Tibet, at least four regional incision periods can be recognized. Chronological data, terrace elevation profiles, and climate proxy records suggest that these terracing periods were triggered by cool and/or wet climatic conditions. A geometric survey of the riverbed longitudinal profile suggests that surface uplift serves as a potential dynamic forcing for long-term incision. A model is proposed for terrace formation as a response to climatic perturbation in an uplifted mountain range.

  10. Observations and modeling of post-midnight uplifts near the magnetic equator

    Directory of Open Access Journals (Sweden)

    M. J. Nicolls


    Full Text Available We report here on post-midnight uplifts near the magnetic equator. We present observational evidence from digital ionosondes in Brazil, a digisonde in Peru, and other measurements at the Jicamarca Radio Observatory that show that these uplifts occur fairly regularly in the post-midnight period, raising the ionosphere by tens of kilometers in the most mild events and by over a hundred kilometers in the most severe events. We show that in general the uplifts are not the result of a zonal electric field reversal, and demonstrate instead that the uplifts occur as the ionospheric response to a decreasing westward electric field in conjunction with sufficient recombination and plasma flux. The decreasing westward electric field may be caused by a change in the wind system related to the midnight pressure bulge, which is associated with the midnight temperature maximum. In order to agree with observations from Jicamarca and Palmas, Brazil, it is shown that there must exist sufficient horizontal plasma flux associated with the pressure bulge. In addition, we show that the uplifts may be correlated with a secondary maximum in the spread-F occurrence rate in the post-midnight period. The uplifts are strongly seasonally dependent, presumably according to the seasonal dependence of the midnight pressure bulge, which leads to the necessary small westward field in the post-midnight period during certain seasons. We also discuss the enhancement of the uplifts associated with increased geomagnetic activity, which may be related to disturbance dynamo winds. Finally, we show that it is possible using simple numerical techniques to estimate the horizontal plasma flux and the vertical drift velocity from electron density measurements in the post-midnight period.

  11. Structural and stratigraphic mapping from satellite imagery, Kalpin uplift, northwestern Tarim basin, northwest China

    Energy Technology Data Exchange (ETDEWEB)

    McKnight, C.L.; Carroll, A.R.; Chu, J.; Hendrix, M.S.; Graham, S.A.; Lyon, R.J.P. (Stanford Univ., CA (USA))


    The Kalpin uplift, located on the northwestern margin of the Tarim craton, northwest China, exposes a complete Paleozoic cratonal stratigraphic sequence. The lack of vegetative cover and the visible color contrasts between stratigraphic units afford an optimal situation for detailed geologic mapping from Landsat Multispectral Scanner imagery at a scale of 1:250,000. Field work in the eastern Kalpin uplift constrains the geologic interpretation of the satellite imagery. Exposed basement rock in the Kalpin uplift consists of deformed and metamorphosed upper Proterozoic strata cut by unmetamorphosed mafic dikes. The overlying sedimentary section was deposited primarily in shallow marine to nonmarine environments and includes Sinian (latest Proterozoic to early Cambrian) siliciclastics and carbonates; Cambrian and Ordovician carbonates; Silurian green shales; Devonian red beds; Carboniferous siliciclastics and carbonates; and Permian carbonates, siliciclastics, and subaerial basalt flows. Paleozoic strata are exposed in a series of low, parallel, curvilinear ranges located at the leading edges of low-angle, southeast-vergent thrust sheets. The regular thrust repetition of the entire Paleozoic section suggests the presence of a detachment horizon within the Cambrian section. These southeast-vergent thrust sheets override an older structural trend on the craton, the Bachu uplift, at right angles, folding as they do so. Strike-slip faults cutting the thrust sheets along the same trend as the Bachu uplift suggest the location of buried lateral ramps associated with the Bachu uplift. The young deformation in the Kalpin uplift is a response to compressive stresses produced by the northward movement of the Indian plate. Major faults in the Tian Shan mountain range to the north have been reactivated, resulting in southward-directed thrusting over the Tarim craton.

  12. Deconvolving regional and fault-driven uplift in Calabria using drainage inversion techniques and field observations (United States)

    Quye-Sawyer, Jennifer; Whittaker, Alexander; Roberts, Gareth; Rood, Dylan


    A key challenge in the Earth Sciences is to understand the timing and extent of the coupling between geodynamics, tectonics, and surface processes. In principle, the landscape adjusts to surface uplift or tectonic events, and present-day topography records a convolution of these processes. The inverse problem, the ability to find the 'best fit' theoretical scenario to match present day observations, is particularly desirable as it makes use of real data, encompasses the complexity of natural systems and quantifies model uncertainty through misfit. The region of Calabria, Italy, is known to have experienced geologically rapid uplift ( 1 mm/yr) since the Early Pleistocene, inferred from widespread marine terraces (ca. 1 Myr old) at elevations greater than 1 km. In addition, this is a tectonically active area of normal faulting with several highly destructive earthquakes in recent centuries. Since there has been some debate about the relative magnitudes of the uplift caused by regional processes or by faulting, the ability to model these effects on a regional scale may help resolve this problem. Therefore, Calabria is both a suitable and important site to model large magnitude recent geomorphic change. 1368 river longitudinal profiles have been generated from satellite digital elevation models (DEMs). These longitudinal profiles were compared to aerial photography to confirm the accuracy of this automated process. The longitudinal profiles contain numerous non-lithologically controlled knickpoints. Field observations support the presence of knickpoints extracted from the DEM and measurements of pebble imbrication from fluvial terraces suggest the planform stability of the drainage network in the last 1 Myr. By assuming fluvial erosion obeys stream power laws with an exponent of upstream area of 0.5 ± 0.1, the evolution of the landscape is computed using a linearized joint inversion of the longitudinal profiles. This has produced a spatially and temporally continuous

  13. Continued Rapid Uplift at Laguna del Maule Volcanic Field (Chile) from 2007 through 2014 (United States)

    Le Mével, H.; Feigl, K. L.; Cordova, L.; DeMets, C.; Lundgren, P.


    The current rate of uplift at Laguna del Maule (LdM) volcanic field in Chile is among the highest ever observed geodetically for a volcano that is not actively erupting. Using data from interferometric synthetic aperture radar (InSAR) and the Global Positioning System (GPS) recorded at five continuously operating stations, we measure the deformation field with dense sampling in time (1/day) and space (1/hectare). These data track the temporal evolution of the current unrest episode from its inception (sometime between 2004 and 2007) to vertical velocities faster than 200 mm/yr that continue through (at least) July 2014. Building on our previous work, we evaluate the temporal evolution by analyzing data from InSAR (ALOS, TerraSAR-X, TanDEM-X) and GPS [ 10.1093/gji/ggt438]. In addition, we consider InSAR data from (ERS, ENVISAT, COSMO-Skymed, and UAVSAR), as well as constraints from magneto-telluric (MT), seismic, and gravity surveys. The goal is to test the hypothesis that a recent magma intrusion is feeding a large, existing magma reservoir. What will happen next? To address this question, we analyze the temporal evolution of deformation at other large silicic systems such as Yellowstone, Long Valley, and Three Sisters, during well-studied episodes of unrest. We consider several parameterizations, including piecewise linear, parabolic, and Gaussian functions of time. By choosing the best-fitting model, we expect to constrain the time scales of such episodes and elucidate the processes driving them.

  14. Spatial and temporal uplift history of South America from calibrated drainage analysis (United States)

    Rodríguez Tribaldos, V.; White, N. J.; Roberts, G. G.; Hoggard, M. J.


    A multidisciplinary approach is used to analyze the Cenozoic uplift history of South America. Residual depth anomalies of oceanic crust abutting this continent help to determine the pattern of present-day dynamic topography. Admittance analysis and crustal thickness measurements indicate that the elastic thickness of the Borborema and Altiplano regions is ≤10 km with evidence for sub-plate support at longer wavelengths. A drainage inventory of 1827 river profiles is assembled and used to investigate landscape development. Linear inverse modeling enables river profiles to be fitted as a function of the spatial and temporal history of regional uplift. Erosional parameters are calibrated using observations from the Borborema Plateau and tested against continent-wide stratigraphic and thermochronologic constraints. Our results predict that two phases of regional uplift of the Altiplano plateau occurred in Neogene times. Regional uplift of the southern Patagonian Andes also appears to have occurred in Early Miocene times. The consistency between observed and predicted histories for the Borborema, Altiplano, and Patagonian plateaux implies that drainage networks record coherent signals that are amenable to simple modeling strategies. Finally, the predicted pattern of incision across the Amazon catchment constrains solid sedimentary flux at the Foz do Amazonas. Observed and calculated flux estimates match, suggesting that erosion and deposition were triggered by regional Andean uplift during Miocene times.

  15. Geomorphic indices and relative tectonic uplift in the Guerrero sector of the Mexican forearc

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    Krzysztof Gaidzik


    The results of the applied landscape analysis reveal considerable variations in relief, topography and geomorphic indices values along the Guerrero sector of the Mexican subduction zone. We argue that the reported differences are indicative of tectonic deformation and of variations in relative tectonic uplift along the studied forearc. A significant drop from central and eastern parts of the study area towards the west in values of RVA (from ∼500 to ∼300, SL (from ∼500 to ca. 400, maximum SL (from ∼1500–2500 to ∼1000 and ksn (from ∼150 to ∼100 denotes a decrease in relative tectonic uplift in the same direction. We suggest that applied geomorphic indices values and forearc topography are independent of climate and lithology. Actual mechanisms responsible for the observed variations and inferred changes in relative forearc tectonic uplift call for further studies that explain the physical processes that control the forearc along strike uplift variations and that determine the rates of uplift. The proposed methodology and results obtained through this study could prove useful to scientists who study the geomorphology of forearc regions and active subduction zones.

  16. A lithospheric instability origin for Columbia River flood basalts and Wallowa Mountains uplift in northeast Oregon. (United States)

    Hales, T C; Abt, D L; Humphreys, E D; Roering, J J


    Flood basalts appear to form during the initiation of hotspot magmatism. The Columbia River basalts (CRB) represent the largest volume of flood basalts associated with the Yellowstone hotspot, yet their source appears to be in the vicinity of the Wallowa Mountains, about 500 km north of the projected hotspot track. These mountains are composed of a large granitic pluton intruded into a region of oceanic lithosphere affinity. The elevation of the interface between Columbia River basalts and other geological formations indicates that mild pre-eruptive subsidence took place in the Wallowa Mountains, followed by syn-eruptive uplift of several hundred metres and a long-term uplift of about 2 km. The mapped surface uplift mimics regional topography, with the Wallowa Mountains in the centre of a 'bull's eye' pattern of valleys and low-elevation mountains. Here we present the seismic velocity structure of the mantle underlying this region and erosion-corrected elevation maps of lava flows, and show that an area of reduced mantle melt content coincides with the 200-km-wide topographic uplift. We conclude that convective downwelling and detachment of a compositionally dense plutonic root can explain the timing and magnitude of Columbia River basalt magmatism, as well as the surface uplift and existence of the observed melt-depleted mantle.

  17. Numerical investigation of underground drain radius, depth and location on uplift pressure reduction (Case study: Tabriz diversion dam)


    Farzin Salmasi; Behnam Mansuri


    Water penetration from beneath of built structures on permeable soils causes uplift force along the contact of structure with foundation. This uplift force reduces hydraulic structure stability. Typically, these instabilities occur due to under-pressure development (uplift force), gradual inner degradation of foundation material (piping) or sand boil phenomenon. Thus, it seems necessary to calculate the pressure applied to the contact surface of the dam. One method for preventing piping pheno...

  18. Formation stage and controlling factors of the paleo-uplifts in the Tarim Basin: A further discussion

    Directory of Open Access Journals (Sweden)

    Yuan Neng


    Full Text Available Various types of paleo-uplifts with different characteristics are developed in the Tarim Basin. Previously, there were multiple opinions on the pale-uplifts origins and structural evolution, so the oil and gas exploration ideas and deployment in the Tarim Basin were not developed smoothly. In this paper, regional seismic interpretation and structural analysis were carried out on the deep marine carbonate rocks in this basin based on the new seismic and drilling data. Then combined with the structural denudation results, the paleo-structural frameworks were reconstructed. And finally, the formation stage and main controlling factors of paleo-uplifts were discussed. It is shown that the Middle Ordovician is the key period when regional extension was converted to compression in this basin, so stratigraphic, sedimentary and structural differences occurred. Before the deposition of Yijianfang Fm in late Middle Ordovician, three carbonate paleo-uplifts (i.e., the Northern, Central and SW Tarim paleo-uplifts begun to appear, and they were all broad-folded paleo-uplifts of nearly E–W striking and were formed at the same stage. The distribution and development of the Phanerozoic uplifts in this basin are restricted by the Northern and Southern Tarim basement pale-uplifts of nearly E–W striking which were developed during the Precambrian. It is indicated that all the three paleo-uplifts are compressional paleo-uplifts originated from the convergence of the southern plate margin based on the basement paleo-uplifts and they are all characterized by similar structural characteristics and inherited formation and evolution. The current differences of paleo-uplifts are controlled by multi-stage intense structural reformation since the Silurian. It is concluded that the oil and gas exploration potential is immense in the carbonate reservoirs of well-preserved deep paleo-structural zones in a larger area.

  19. Quantifying rock uplift rates using channel steepness and cosmogenic nuclide–determined erosion rates: Examples from northern and southern Italy (United States)

    Cyr, Andrew J.; Granger, Darryl E.; Olivetti, Valerio; Molin, Paola


    Rock uplift rates can be difficult to measure over 103–105 yr time scales. If, however, a landscape approaches steady state, where hillslope erosion and rock uplift rates are steady and locally similar, then it should be possible to quantify rock uplift rates from hillslope erosion rates. Here, we test this prediction by comparing channel steepness index values and 10Be catchment-averaged erosion rates to well-constrained rock uplift rates in two landscapes in Italy. The first field area is the Romagna Apennines, northern Italy, where rock uplift rates are relatively uniform, between 0.2 and 0.5 mm/yr (regional mean 0.40 ± 0.15 [SE] mm/yr), and have been steady since 0.9 Ma. The second area is the region around northeastern Sicily and the southernmost Italian peninsula, where rock uplift rates are higher and exhibit a strong spatial gradient, from ∼0.7 to ∼1.6 mm/yr (regional mean 1.09 ± 0.13 [SE] mm/yr). In both regions, channel steepness indices and 10Be erosion rates vary directly with rock uplift rates. Although there is considerable variability in erosion rates, regionally averaged rates in both the northern (0.46 ± 0.04 [SE] mm/yr) and southern (1.21 ± 0.24 [SE] mm/yr) areas accurately measure rock uplift rates. Although channel steepness indices do not quantify rock uplift rates, they are useful for (1) identifying regional patterns of rock uplift, (2) identifying areas where uplift rates might be expected to be uniform, and (3) informing 10Be sampling strategies. This study demonstrates that, together, channel steepness and hillslope erosion rates can provide a powerful tool for determining rock uplift rates.

  20. Numerical investigation of underground drain radius, depth and location on uplift pressure reduction (Case study: Tabriz diversion dam

    Directory of Open Access Journals (Sweden)

    Farzin Salmasi


    Full Text Available Water penetration from beneath of built structures on permeable soils causes uplift force along the contact of structure with foundation. This uplift force reduces hydraulic structure stability. Typically, these instabilities occur due to under-pressure development (uplift force, gradual inner degradation of foundation material (piping or sand boil phenomenon. Thus, it seems necessary to calculate the pressure applied to the contact surface of the dam. One method for preventing piping phenomenon, reduction in exit gradient as well as decrease of uplift force beneath diversion dams includes implementation of weep hole. This study aims to study the effect of radius, depth and location of pipe drains under stilling basin upon how much uplift force decreases. The benefit of this study in agricultural field for soil and water engineers is to have a safe design of lined canals, weirs or diversion dams. To do this, numerical simulation of Tabriz diversion dam with Geo-Studio software was carried out. Results showed that application of drain pipe under the structure reduced uplift force respect to without drain under the structure. Increasing of drain radius; caused reduction of uplift pressure more but increased of seepage flow slightly. Installation of drain in upper part of stilling basin had a tendency to decrease uplift pressure more. Existence of drain near the stilling basin bottom caused in more reducing of uplift pressure than of installation of it in deeper depth

  1. New constraints on Holocene uplift rates for the Baudo Mountain Range, northwestern Colombia (United States)

    González, Juan L.; Shen, Zhixiong; Mauz, Barbara


    A beach deposit on the southern end of the Baudo Mountain Range, at an elevation of ˜2.0 m above the backshore of the modern beach, was dated at ˜2870 years using optically stimulated luminescence dating. The calculated average uplift rate necessary to raise this deposit is 0.7 mm/yr. This rate combines the long-term regional deformation associated with the subduction of the Nazca Plate under the South American Plate and the collision of the Choco Block microplate against the South American continent, as well as uplift from local faults. We propose that rapid emergence probably as several pulses, each involving decimeter scale coseismic uplift, is likely to have occurred to elevate the beach above the intertidal zone and offset destructive wave erosion.

  2. Greenland uplift and regional sea level changes from ICESat observations and GIA modelling

    DEFF Research Database (Denmark)

    Spada, G.; Ruggieri, G.; Sørensen, Louise Sandberg


    We study the implications of a recently published mass balance of the Greenland ice sheet (GrIS), derived from repeated surface elevation measurements from NASA’s ice cloud and land elevation satellite (ICESat) for the time period between 2003 and 2008. To characterize the effects of this new, high...... of Greenland. Long‐wavelength uplifts and gravity variations in response to current or past ice thickness variations are obtained solving the sea level equation, which accounts for both the elastic and the viscoelastic components of deformation. To capture the short‐wavelength components of vertical uplift...... in response to current ice mass loss, which is not resolved by satellite gravity observations, we have specifically developed a high‐resolution regional elastic rebound (ER) model. The elastic component of vertical uplift is combined with estimates of the viscoelastic displacement fields associated...

  3. Postglacial uplift of the Earth crust in the North-Western part of the Kola region

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    Tolstobrov D.S.


    Full Text Available The new lithological, micropaleontological and chronological data received as a result of studying the lake bottom sediments sequences in a valley of the Tuloma River have been presented. Investigation of lakes situated in different areas of the Tuloma River valley at different elevations and their correlation with position of ancient marine coastal lines and forms has allowed recognizing the character of sedimentation and specific of neotectonic movements of the Earth's crust in the Late Glacial and Holocene in the North-Western part of the Kola region. The equidistant diagram of relative lines of the Earth's crust uplift has been presented for the studied area. The magnitude of the different-age uplift correlated to these lines, and uplift gradient along the valley of the Tuloma River and Kola Bay of the Barents Sea has been estimated

  4. Coastal uplift and mortality of intertidal organisms caused by the september 1985 Mexico earthquakes. (United States)

    Bodin, P; Klinger, T


    Coastal uplift associated with the great Mexican earthquake of 19 September 1985 and its principal aftershock produced widespread mortality of intertidal organisms along the coast of the states of Michoacán and Guerrero, Mexico. Measurements of the vertical extent of mortality at ten sites provided estimates of the magnitude of the vertical component of deformation along the coast. Within the affected area, uplift ranged from about 12 centimeters to about 1 meter, and no subsidence was observed. The observations are consistent with models of the tectonic deformation that results from buried slip on a shallow-dipping underthrust fault.

  5. Ordovician gas exploration breakthrough in the Gucheng lower uplift of the Tarim Basin and its enlightenment


    Zhaoming, Wang; Haijun, Yang; Yingmin, Qi; Yongquan, Chen; Yanlong, Xu


    A steady high yield natural gas flow was tapped in the Ordovician strata of Well Gucheng 6 drilled in the Gucheng lower uplift in the Tarim Basin in 2012, marking the discovery of another carbonate gas exploration field after the other two fields in the middle and northern Tarim Basin (the so called Tazhong and Tabei in the industry). The exploration in the Gucheng lower uplift has experienced three stages: the first stage, marine facies clastic exploration from 1995 to 2003, focusing on the ...

  6. The flux-scaling scenario. De Sitter uplift and axion inflation

    Energy Technology Data Exchange (ETDEWEB)

    Blumenhagen, Ralph; Damian, Cesar; Herschmann, Daniela; Sun, Rui [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Muenchen (Germany); Font, Anamaria [Departamento de Fisica, Centro de Fisica Teorica y Computacional, Facultad de Ciencias, Universidad Central de Venezuela, Caracas (Venezuela, Bolivarian Republic of)


    Non-geometric flux-scaling vacua provide promising starting points to realize axion monodromy inflation via the F-term scalar potential. We show that these vacua can be uplifted to Minkowski and de Sitter by adding an D3-brane or a D-term containing geometric and non-geometric fluxes. These uplifted non-supersymmetric models are analyzed with respect to their potential to realize axion monodromy inflation self-consistently. Admitting rational values of the fluxes, we construct examples with the required hierarchy of mass scales. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Geomechanical modeling of surface uplift around well KB-502 at the in Salah CO2 storage site

    NARCIS (Netherlands)

    Fokker, P.A.; Orlic, B.; Meer, L.G.H. van der; Geel, C.R.


    Injection of CO2 in the InSalah field has caused uplift of the surface, as observed by satellite geodetic techniques (InSAR). Around one of the wells, KB-502, the uplift shows anomalous behaviour: a two-lobe pattern develops in the direction of the preferred fracture orientation. This indicates the

  8. Seismic Hazards Implications of Uplifted Pleistocene Coral Terraces in the Gulf of Aqaba. (United States)

    Bosworth, W; Montagna, P; Pons-Branchu, E; Rasul, N; Taviani, M


    The Gulf of Aqaba transform plate boundary is a source of destructive teleseismic earthquakes. Seismicity is concentrated in the central sub-basin and decreases to both the north and south. Although principally a strike-slip plate boundary, the faulted margins of the Gulf display largely dip-slip extensional movement and accompanying footwall uplift. We have constrained rates of this uplift by measurements of elevated Pleistocene coral terraces. In particular the terrace that formed during the last interglacial (~125 ka) is found discontinuously along the length of the Gulf at elevations of 3 to 26 m. Global sea level was ~7 m higher than today at 125 ka indicating net maximum tectonic uplift of ~19 m with an average rate of ~0.015 cm/yr. Uplift has been greatest adjacent to the central sub-basin and like the seismicity decreases to the north and south. We suggest that the present pattern of a seismically active central region linked to more aseismic areas in the north and south has therefore persisted for at least the past 125 kyr. Consequently the potential for future destructive earthquakes in the central Gulf is greater than in the sub-basins to the north and south.

  9. For Their Musical Uplift: Emma Azalia Hackley and Voice Culture in African American Communities (United States)

    Karpf, Juanita


    The noted African American soprano Emma Azalia Hackley (1867-1922) abandoned her concert career in the early twentieth century and began travelling throughout the United States, organizing community choruses and promoting community music making. She spent the remainder of her life engaged in what she called "musical social uplift", which entailed…

  10. Passive margin uplifts and their influence on climatic change and weathering patterns of tropical shield regions

    Energy Technology Data Exchange (ETDEWEB)

    Gunnell, Yanni [Laboratoire de Geographie Physique, CNRS UPRES-A 6042 Clermont-Ferrand, and Departement de Geographie, Universite Paris 7, 2 place Jussieu, Case 7001, 75251 Paris (France)


    Large scale plateau uplift influences long-term atmospheric circulation patterns. Recent speculation on the role of passive margin mountains in initiating late Cenozoic glaciation around the North Atlantic adds to the debate on the connections between tectonics and climate patterns, and calls for broadening the scope of examining causes of climate change to include other existing passive margins. Three examples from the intertropical zone, the Western Ghats of India, the Borborema of northeast Brazil, and the West African Leo uplift are compared. Palaeoenvironmental and fission track constraints on amplitude, timing and wavelength of the shoulder uplift history for the Western Ghats reveal that high elevation margins can act as effective environmental filters, both as physical barriers to atmospheric circulation and as pace-makers for denudation rates, which in turn steer weathering processes towards producing specific soil and vegetation suites. Predicting interaction between climate and rift-flank tectonics is however shown to be model-dependent, in that assumptions on whether uplift is transient or permanent will influence the timescales and effectiveness of any consequent environmental change

  11. Passive margin uplifts and their influence on climatic change and weathering patterns of tropical shield regions (United States)

    Gunnell, Yanni


    Large scale plateau uplift influences long-term atmospheric circulation patterns. Recent speculation on the role of passive margin mountains in initiating late Cenozoic glaciation around the North Atlantic adds to the debate on the connections between tectonics and climate patterns, and calls for broadening the scope of examining causes of climate change to include other existing passive margins. Three examples from the intertropical zone, the Western Ghats of India, the Borborema of northeast Brazil, and the West African Leo uplift are compared. Palaeoenvironmental and fission track constraints on amplitude, timing and wavelength of the shoulder uplift history for the Western Ghats reveal that high elevation margins can act as effective environmental filters, both as physical barriers to atmospheric circulation and as pace-makers for denudation rates, which in turn steer weathering processes towards producing specific soil and vegetation suites. Predicting interaction between climate and rift-flank tectonics is however shown to be model-dependent, in that assumptions on whether uplift is transient or permanent will influence the timescales and effectiveness of any consequent environmental change.

  12. A stable isotope record of late Cenozoic surface uplift of southern Alaska (United States)

    Bill, Nicholas S.; Mix, Hari T.; Clark, Peter U.; Reilly, Sean P.; Jensen, Britta J. L.; Benowitz, Jeffrey A.


    Although the timing of an acceleration in late-Cenozoic exhumation of southern Alaska is reasonably well constrained as beginning ∼5-∼6 Ma, the surface uplift history of this region remains poorly understood. To assess the extent of surface uplift relative to rapid exhumation, we developed a stable isotope record using the hydrogen isotope composition (δD) of paleo-meteoric water over the last ∼7 Ma from interior basins of Alaska and Yukon Territory. Our record, which is derived from authigenic clays (δDclay) in silicic tephras, documents a ∼50-60‰ increase in δD values from the late Miocene (∼6-∼7 Ma) through the Plio-Pleistocene transition (∼2-∼3 Ma), followed by near-constant values over at least the last ∼2 Ma. Although this enrichment trend is opposite that of a Rayleigh distillation model typically associated with surface uplift, we suggest that it is consistent with indirect effects of surface uplift on interior Alaska, including changes in aridity, moisture source, and seasonality of moisture. We conclude that the δDclay record documents the creation of a topographic barrier and the associated changes to the climate of interior Alaska and Yukon Territory.

  13. Tiotropium as a first maintenance drug in COPD: secondary analysis of the UPLIFT trial

    DEFF Research Database (Denmark)

    Troosters, T; Celli, B; Lystig, T


    -term Impacts on Function with Tiotropium (UPLIFT) was conducted. Analysis focused on the effect of tiotropium versus matching placebo in the 810 (13.5%) COPD patients not on other maintenance treatment (long-acting beta-agonists, inhaled corticosteroids, theophyllines or anticholinergics) at randomisation...

  14. Calculation of ejecta thickness and structural uplift for Lunar and Martian complex crater rims. (United States)

    Krüger, Tim; Sturm, Sebastian; Kenkmann, Thomas


    Crater rims of simple and complex craters have an elevation that is formed during the excavation stage of crater formation. For simple crater rims it is believed that the elevation is due to the sum of two equal parts, the thickness of the most proximal impact ejecta blanket (overturned flap) plus the thickness that results from plastic deformation including injection [1, 2, 3]. We intend to measure and quantify the kinematics of mass movements, especially concerning the question why complex impact craters have elevated crater rims like simple craters and precisely constrain the ejecta thickness and structural uplift of Lunar and Martian crater rims to understand what the main contributor to the elevated rim is [4]. We investigated a pristine 16 km-diameter unnamed Martian complex crater (21.52°N, 184.35°) and the lunar complex craters Bessel (21.8°N, 17.9°E) 16 km in diameter and Euler (23.3°N, 29.2°W) 28 km in diameter [5, 6]. In the crater walls of these craters we found columnar lavas on Mars and basaltic layering on the Moon. We used the uppermost layers of these exposed outcrops along the crater wall to determine the dip of the target rocks (Mars) and to distinguish between the bedrock and the overlying ejecta. We precisely measured the structural uplift and ejecta thickness of these complex craters. The unnamed crater on Mars has a mean rim height of 375.75 m, with a structural uplift of 233.88 m (57.44%), exposed as columnar lavas and the superposing ejecta has a height of 141.87 m (43.56%). For the Lunar complex crater Euler the mean total rim height is 790 ± 100 m, with a minimal structural uplift of 475 ± 100 m (60 ± 10 %), exposed as basaltic layers [e.g., 7, 8] and a maximum ejecta thickness of 315 ± 100 m (40 ± 10%). The Lunar complex crater Bessel has a total rim height of 430 ± 15 m , with a minimal structural uplift of 290 ± 15 m (67 ± 3 %), exposed as basaltic layers and a maximum ejecta thickness of 140 ± 115 m (33 ± 3%). For the

  15. Hydrocarbon Accumulation and Distribution Characteristics of the Silurian in the Tazhong Uplift of Tarim Basin (United States)

    LÜ, Xiuxiang; BAI, Zhongkai; ZHAO, Fengyun

    Hydrocarbon accumulation of the Silurian in the Tazhong uplift of Tarim basin is characterized by "two sources and three stages". "Two sources" means that the hydrocarbons are derived from two source rocks of the Cambrian and Middle-Upper Ordovician. "Three stages" means that asphalt and movable oil undergoes three hydrocarbon accumulation stages, i.e., Late Caledonian, Late Hercynian, and Yanshanian-Himalayan. The formation of asphalt resulted from the destruction of the hydrocarbons accumulated and migrated in the early stages. The present movable oil, mostly derived from Middle-Upper Ordovician source rock, resulted from the hydrocarbons accumulated in the late stage. There are three types of reservoirs, i.e., anticline structural, stratigraphic lithological, and lava shield reservoirs in the Tazhong uplift. Hydrocarbon accumulation of the Silurian in the Tazhong uplift is controlled by the three factors. (1) The background of uplift structure. Around the ancient uplift, the compounding of many types makes up the composite hydrocarbon accumulation areas. (2) Effective cover. The show of oil gas including asphalt, heavy crude oil, and normal oil is quite active in the Silurian. Asphalt and heavy crude oil are distributed under the red mudstone member and movable oil is distributed under the gray mudstone member. (3) High quality reservoir bed. Sandstone is distributed widely in the Tazhong area. Reservoir pore space can be divided into three types: a) secondary origin-primary origin pore space; b) primary origin-secondary origin pore space, and c) micropore space. Porosity is 3.3-17.4%, and permeability is (0.1-667.97) × 10 -3 μm 2.

  16. Quantification of surface uplift by using paleo beach deposits (Oman, Northern Indian Ocean) (United States)

    Hoffmann, Gösta; Schneider, Bastian; Monschau, Martin; Mechernich, Silke


    The study focusses on a coastal area along the Arabian Sea in Oman. Here, a staircase of marine terraces is seen as geomorphological evidence suggesting sub-recent uplift of a crustal block in the northeast of the Arabian Peninsula. The erosional terraces are cut into Paleocene to Early Eocene limestone formations. These limestone formations are underlain by allochtonous ophiolites. We mapped the terraces over a distance of 60 km and identified at least 8 terrace levels in elevations up to 350 m above present sea level. The uppermost terraces are erosional, whereas the lower ones are depositional in style. Mollusc and coral remains as well as beach-rock are encountered on the terrace surfaces. The formations are dissected by NW-SE trending faults. Some of the terraces are very pronounced features in the landscape and easy to trace, others are partly eroded and preserved as remnants only. The deposit along the shoreline angle act as a datum making use of the fact that the rocks formed in a defined horizontal level which is the paleo-sea level. Hence, any offset from the primary depositional level is evidence for neotectonic movements. We utilise differential GPS to map the elevation of beachrock deposits. Age constraints on terrace formation is derived by sampling the beachrock deposits and dating using cosmogenic nuclii. The results indicate ongoing uplift in the range of less than a millimetre per year. The uplift is differential as the terraces are tilted. We mapped oblique normal and strike-slip faults in the younger terraces. We hypothesise that the mechanism responsible for the uplift is not tectonics but driven by the serpentinisation of the ophiolite that underlie the limestone formations. One process during the serpentinisation is the hydration of the mantle rocks which is responsible for a decrease in density. The resulting buoyancy and significant solid volume increase lead to the observed deformation including uplift.

  17. Timing of the Southern African Plateau uplift : a couple landforms-margin study of Southern Namibia (United States)

    Guillocheau, François; Dauteuil, Olivier; Baby, Guillaume; Pickford, Martin; Senut, Brigitte


    The timing of the uplift of the Southern African (or Kalahari) Plateau is debated, with four scenarios of uplift: (1) at time of rifting (Early Cretaceous), (2) during Late Cretaceous, (3) around the Eocene-Oligocene boundary and (4) during Pliocene times. This knowledge is of primary importance for a better understanding of the mantle processes at the origin of this very long wavelength structure. To answer this question, we studied the key area of the northern Orange Margin (sequence stratigraphic analysis of seismic lines and wells), offshore of the Sperrgebiet. This study is coupled with an analysis of the landforms dated with associated sediments and volcanics. (1) The first uplift of the Plateau was during Late Cretaceous times, with a first increase of siliciclastic sediments supply during Late Cenomanian (95-90 Ma) in response to the beginning of the uplift along the Indian Ocean side that propagates eastward around the Campanian (85-70 Ma). (2) Because of the humid climatic conditions prevailing since Santonian (85 Ma), most of the relief of this first plateau is removed by erosion. At the end of the planation of this topography, chemical erosion is dominant with the growth of thick lateritic profiles (55?-45 Ma). (3) A second uplift of the Plateau occurred during Late Eocene-Early Oligocene (30-40 Ma - paroxysm) and Miocene with the incision of at least three generations of pediments that shape the present-day ""Great"" Escarpment. (4) This "old" Oligocene relief is probably preserved because of the decrease of the erosion due to the climate aridification, starting at Middle Miocene times (around 15 Ma).

  18. Mechanisms of crustal uplift and subsidence at the Yellowstone caldera, Wyoming (United States)

    Dzurisin, D.; Yamashita, K.M.; Kleinman, J.W.


    Leveling surveys in 1923, 1976, and each year from 1983 to 1993 have shown that the east-central part of the Yellowstone caldera, near the base of the Sour Creek resurgent dome, rose at an average rate of 14??1 mm/year from 1923 to 1976 and 22??1 mm/year from 1976 to 1984. In contrast, no detectable movement occurred in the same area from 1984 to 1985 (-2??5 mm/year), and from 1985 to 1993 the area subsided at an average rate of 19??1 mm/year. We conclude that uplift from 1923 to 1984 was caused by: (1) pressurization of the deep hydrothermal system by fluids released from a crystallizing body of rhyolite magma beneath the caldera, then trapped beneath a self-sealed zone near the base of the hydrothermal system; and (2) aseismic intrusions of magma into the lower part of the sub-caldera magma body. Subsidence since 1985 is attributed to: (1) depressurization and fluid loss from the deep hydrothermal system, and (2) sagging of the caldera floor in response to regional crustal extension. Future intrusions might trigger renewed eruptive activity at Yellowstone, but most intrusions at large silicic calderas seem to be accommodated without eruptions. Overpressurization of the deep hydrothermal system could conceivably result in a phreatic or phreatomagmatic eruption, but this hazard is mitigated by episodic rupturing of the self-sealed zone during shallow earthquake swarms. Historical ground movements, although rapid by most geologic standards, seem to be typical of inter-eruption periods at large, mature, silicic magma systems like Yellowstone. The greatest short-term hazards posed by continuing unrest in the Yellowstone region are: (1) moderate to large earthquakes (magnitude 5.5-7.5), with a recurrence interval of a few decdes; and (2) small hydrothermal explosions, most of which affect only a small area (<0.01 km2), with a recurrence interval of a few years. ?? 1994 Springer-Verlag.

  19. Evolution and variability of the Asian monsoon and its potential linkage with uplift of the Himalaya and Tibetan Plateau (United States)

    Tada, Ryuji; Zheng, Hongbo; Clift, Peter D.


    Uplift of the Himalaya and Tibetan Plateau (HTP) and its linkage with the evolution of the Asian monsoon has been regarded as a typical example of a tectonic-climate linkage. Although this linkage remains unproven because of insufficient data, our understanding has greatly advanced in the past decade. It is thus timely to summarize our knowledge of the uplift history of the HTP, the results of relevant climate simulations, and spatiotemporal changes in the Indian and East Asian monsoons since the late Eocene. Three major pulses of the HTP uplift have become evident: (1) uplift of the southern and central Tibetan Plateau (TP) at ca. 40-35 Ma, (2) uplift of the northern TP at ca. 25-20 Ma, and (3) uplift of the northeastern to eastern TP at ca. 15-10 Ma. Modeling predictions suggest that (i) uplift of the southern and central TP should have intensified the Indian summer monsoon (ISM) and the Somali Jet at 40-35 Ma; (ii) uplift of the northern TP should have intensified the East Asian summer monsoon (EASM) and East Asian winter monsoon (EAWM), as well as the desertification of inland Asia at 25-20 Ma; and (iii) uplift of the northeastern and eastern TP should have further intensified the EASM and EAWM at 15-10 Ma. We tested these predictions by comparing them with paleoclimate data for the time intervals of interest. There are insufficient paleoclimate data to test whether the ISM and Somali Jet intensified with the uplift of the southern and central TP at 40-35 Ma, but it is possible that such uplift enhanced erosion and weathering that drew down atmospheric CO2 and resulted in global cooling. There is good evidence that the EASM and EAWM intensified, and desertification started in inland Asia at 25-20 Ma in association with the uplift of the northern TP. The impact of the uplift of the northeastern and eastern TP on the Asian monsoon at 15-10 Ma is difficult to evaluate because that interval was also a time of global cooling and Antarctic glaciation that might also

  20. Relative Quantification of Costal Cordillera (Ecuador) Uplift : Preliminary Results from Quantitative Geomorphology (United States)

    Reyes, Pedro; Dauteuil, Olivier; Michaud, François


    The coastal cordillera of Ecuador (culminating point around 800 m) includes on its littoral margins uplifted marine terraces (maximum known 360 m). The coastal cordillera constitutes an important barrier of drainage and on nearly 600 km the drainage resulting from the Andes is diverted towards Río Guayas in the South and Río Esmeraldas in North. What is the uplifting mode of the coastal cordillera? For how long it has constituted a barrier of drainage? Does the coastal cordillera rising be linked with the littoral margin rising? Does the cordillera have raised in a homogeneous or segmented way? What is the geodynamic process of the uplift of the cordillera? Can this uplift be related with the subduction of the Carnegie ridge? The first objective of this work is to analyze the morphology of the coastal cordillera with helps of quantitative geomorphology using digital techniques such as DEM (realized with a resolution of 30 m by Marc Souris, IRD), to specify the evolution of the coastal cordillera uplift. This study was carried out starting combining analysis of morphology, maps derived from the slopes and anomalies of the drainage of the hydrographic network. In the second time, three methods were applied to DEM data using the ArcGIS software: 1) the digitalization and the interpolation of basal surface of the last marine formation of regional distribution (the Borbón formation on the geological map of Ecuador) to determine paleo-horizontal and to see its deformation; 2) the extraction of 109 profiles of rivers which allow us to calculate for each river the vertical, horizontal, and total deviation compared to the theoretical profile of the river and the associated SL index; 3) the measurement of the relief incision (depth + half width of the valley, on the whole 7500 measurements) according to the method of Bonnet et al. (1998). We adapted this method to be able to represent the state of incision in any point, correcting from the influence of the lithology and

  1. Exploring southern African Plateau uplift with landscape evolution model inversion and erosion history data (United States)

    Stanley, Jessica; Braun, Jean; Flowers, Rebecca; Guillocheau, François; Robin, Cécile; Baby, Guillaume


    The southern African plateau is a dominant feature of African topography but there is considerable debate about when and how it formed. Cretaceous kimberlite activity and the presence of a large low shear seismic velocity province (LLSVP) in the deep mantle below southern Africa have lead many to propose uplift related to mantle processes. Better constraints on the timing of uplift have the potential to constrain the nature of the LLSVP and the source of support for southern Africa's anomalous elevations. However, surface uplift is difficult to detect directly in the geologic record and the relationships between mantle-sourced uplift and erosion are not necessarily direct. Here, we use a landscape evolution model combined with data constraining the spatiotemporal erosion patterns across southern Africa to explore how topographic development and erosion are related. This is an ideal location to utilize this approach because several recent studies have helped to constrain the erosion history of this region over different spatial and temporal scales but the uplift history is still widely debated. We integrate a highly efficient landscape evolution model (FastScape, Braun and Willett, 2013) and a thermal module with a large low temperature thermochronology dataset, sedimentary flux volumes for the major offshore basins, and geologic observations to address these questions. We used inversion methods based on the Neighborhood Algorithm to investigate how data is best simulated by the model while varying model parameters related to plateau uplift and the physical characteristics of the eroding material. This is a powerful approach because we are able to compare model outputs to many aspects of topographic shape and constraints on the erosion history simultaneously. Results from the inversions show that the data are sufficient to constrain many model parameters. Additionally, we show that the combination of different types of data, and in particular the spatiotemporal

  2. Evaluation of Multi Canister Overpack (MCO) Handling Machine Uplift Restraint for a Seismic Event During Repositioning Operations

    Energy Technology Data Exchange (ETDEWEB)



    Insertion of the Multi-Canister Overpack (MCO) assemblies into the Canister Storage Building (CSB) storage tubes involves the use of the MCO Handling Machine (MHM). During MCO storage tube insertion operations, inadvertent movement of the MHM is prevented by engaging seismic restraints (''active restraints'') located adjacent to both the bridge and trolley wheels. During MHM repositioning operations, the active restraints are not engaged. When the active seismic restraints are not engaged, the only functioning seismic restraints are non-engageable (''passive'') wheel uplift restraints which function only if the wheel uplift is sufficient to close the nominal 0.5-inch gap at the uplift restraint interface. The MHM was designed and analyzed in accordance with ASME NOG-1-1995. The ALSTHOM seismic analysis reported seismic loads on the MHM uplift restraints and EDERER performed corresponding structural calculations to demonstrate structural adequacy of the seismic uplift restraint hardware. The ALSTHOM and EDERER calculations were performed for a parked MHM with the active seismic restraints engaged, resulting in uplift restraint loading only in the vertical direction. In support of development of the CSB Safety Analysis Report (SAR), an evaluation of the MHM seismic response was requested for the case where the active seismic restraints are not engaged. If a seismic event occurs during MHM repositioning operations, a moving contact at a seismic uplift restraint would introduce a friction load on the restraint in the direction of the movement. These potential horizontal friction loads on the uplift restraints were not included in the existing restraint hardware design calculations. One of the purposes of the current evaluation is to address the structural adequacy of the MHM seismic uplift restraints with the addition of the horizontal friction associated with MHM repositioning movements.

  3. Observations of mesoscale and boundary-layer scale circulations affecting dust transport and uplift over the Sahara

    Directory of Open Access Journals (Sweden)

    J. H. Marsham


    Full Text Available Observations of the Saharan boundary layer, made during the GERBILS field campaign, show that mesoscale land surface temperature variations (which were related to albedo variations induced mesoscale circulations. With weak winds along the aircraft track, land surface temperature anomalies with scales of greater than 10 km are shown to significantly affect boundary-layer temperatures and winds. Such anomalies are expected to affect the vertical mixing of the dusty and weakly stratified Saharan Residual Layer (SRL. Mesoscale variations in winds are also shown to affect dust loadings in the boundary layer.

    Using the aircraft observations and data from the COSMO model, a region of local dust uplift, with strong along-track winds, was identified in one low-level flight. Large eddy model (LEM simulations based on this location showed linearly organised boundary-layer convection. Calculating dust uplift rates from the LEM wind field showed that the boundary-layer convection increased uplift by approximately 30%, compared with the uplift rate calculated neglecting the convection. The modelled effects of boundary-layer convection on uplift are shown to be larger when the boundary-layer wind is decreased, and most significant when the mean wind is below the threshold for dust uplift and the boundary-layer convection leads to uplift which would not otherwise occur.

    Both the coupling of albedo features to the atmosphere on the mesoscale, and the enhancement of dust uplift by boundary-layer convection are unrepresented in many climate models, but may have significant impacts on the vertical transport and uplift of desert dust. Mesoscale effects in particular tend to be difficult to parametrise.

  4. Surface uplift and time-dependent seismic hazard due to fluid-injection in eastern Texas (United States)

    Shirzaei, M.; Ellsworth, W. L.; Tiampo, K. F.; González, P. J.; Manga, M.


    US states such as Texas and Oklahoma that produce high-volumes of unconventional oil and gas, are facing a sharp increase in seismicity. Observations of the associated surface deformation and accompanying physical models that unequivocally link the seismicity and waste water injection are scarce. Here, we find that the waste water injection in eastern Texas causes uplift, detectable using radar interferometric data. Combining the uplift and injection data through a poroelastic model allows for the resolution of a complex crustal distribution of hydraulic conductivity and pore pressure. We find that the ~5 years pore pressure increase is capable of triggering the 17 May 2012, Mw 4.8 earthquake, the largest event recorded in east Texas. This study shows that surface deformation data are vital in order to constrain the spatiotemporal variations of the stress field in the vicinity of injection sites.

  5. Surface uplift and time-dependent seismic hazard due to fluid injection in eastern Texas. (United States)

    Shirzaei, Manoochehr; Ellsworth, William L; Tiampo, Kristy F; González, Pablo J; Manga, Michael


    Observations that unequivocally link seismicity and wastewater injection are scarce. Here we show that wastewater injection in eastern Texas causes uplift, detectable in radar interferometric data up to >8 kilometers from the wells. Using measurements of uplift, reported injection data, and a poroelastic model, we computed the crustal strain and pore pressure. We infer that an increase of >1 megapascal in pore pressure in rocks with low compressibility triggers earthquakes, including the 4.8-moment magnitude event that occurred on 17 May 2012, the largest earthquake recorded in eastern Texas. Seismic activity increased even while injection rates declined, owing to diffusion of pore pressure from earlier periods with higher injection rates. Induced seismicity potential is suppressed where tight confining formations prevent pore pressure from propagating into crystalline basement rocks. Copyright © 2016, American Association for the Advancement of Science.

  6. Tectonic and erosion-driven uplift in the Gamburtsev Subglacial Mountains of East Antarctica (United States)

    Ferraccioli, Fausto; Jordan, Tom; Watts, Tony; Bell, Robin; Jamieson, Stewart; Finn, Carol; Damaske, Detlef


    Understanding the mechanisms leading to intraplate mountain building remains a significant challenge in Earth Sciences compared to ranges formed along plate margins. The most enigmatic intraplate mountain range on Earth is the Gamburtsev Subglacial Mountains (GSM) located in the middle of the Precambrian East Antarctic Craton. During the International Polar Year, the AGAP project acquired 120,000 line km of new airborne geophysical data (Bell et al., 2011, Science) and seismological observations (Hansen et al., 2010, EPSL) across central East Antarctica. Models derived from these datasets provide new geophysical perspectives on crustal architecture and possible uplift mechanisms for the enigmatic GSM (Ferraccioli et al., 2011, Nature). The geophysical data define a 2,500-km-long Paleozoic to Mesozoic rift system in East Antarctica surrounding the GSM. A thick high-density lower crustal root is partially preserved beneath the range and has been interpreted as formed during the Proterozoic assembly of East Antarctica. Rifting could have triggered phase/density changes at deep crustal levels, perhaps restoring some of the latent root buoyancy, as well as causing rift-flank uplift. Permian rifting is well-established in the adjacent Lambert Rift, and was followed by Cretaceous strike-slip faulting and transtension associated with Gondwana break-up; this phase may have provided a more recent tectonic trigger for the initial uplift of the modern GSM. The Cretaceous rift-flank uplift model for the Gamburtsevs is appealing because it relates the initiation of intraplate mountain-building to large-scale geodynamic processes that led to the separation of Greater India from East Antarctica. It is also consistent with several geological and geophysical interpretations within the Lambert Rift. However, recent detrital thermochrology results from Oligocene-Quaternary sediments in Prydz Bay (Tochlin et al., 2012, G3) argue against the requirement for major Cretaceous rift

  7. Accelerated uplift and magmatic intrusion of the Yellowstone caldera, 2004 to 2006. (United States)

    Chang, Wu-Lung; Smith, Robert B; Wicks, Charles; Farrell, Jamie M; Puskas, Christine M


    The Yellowstone caldera began a rapid episode of ground uplift in mid-2004, revealed by Global Positioning System and interferometric synthetic aperture radar measurements, at rates up to 7 centimeters per year, which is over three times faster than previously observed inflation rates. Source modeling of the deformation data suggests an expanding volcanic sill of approximately 1200 square kilometers at a 10-kilometer depth beneath the caldera, coincident with the top of a seismically imaged crustal magma chamber. The modeled rate of source volume increase is 0.1 cubic kilometer per year, similar to the amount of magma intrusion required to supply the observed high heat flow of the caldera. This evidence suggests magma recharge as the main mechanism for the accelerated uplift, although pressurization of magmatic fluids cannot be ruled out.

  8. Surface uplift and atmospheric flow deflection in the Late Cenozoic southern Sierra Nevada (United States)

    Mix, H.; Caves, J. K.; Winnick, M.; Ritch, A. J.; Reilly, S.; Chamberlain, C. P.


    Given the intimate links between topography, tectonics, climate and biodiversity, considerable effort has been devoted to developing robust elevation histories of orogens. In particular, quantitative geochemical reconstructions using stable oxygen and hydrogen isotopes have been applied to many of the world's mountain belts. Yet after decades of study, determining the Cenozoic surface uplift history of the Sierra Nevada remains a challenge. While geological and geophysical evidence suggests the southern Sierra underwent 1-2 km of Late Cenozoic surface uplift, stable isotope paleoaltimetry studies to date have been restricted to the Basin and Range interior. Recent advances in atmospheric modeling have suggested that such stable isotope records from leeward sites can be affected by the complicating role that sufficiently elevated topography such as the southern (High) Sierra plays in diverting atmospheric circulation. In order to examine the potential role of these terrain blocking effects, we produced stable isotope records from three Late Cenozoic sedimentary basins in the Eastern Sierra and Basin and Range: 1) Authigenic clay minerals in the Mio-Pliocene Verdi Basin (VB), 2) Fluvial and lacustrine carbonates from the Plio-Pleistocene Coso Basin (CB), and 3) Miocene to Holocene pedogenic, fluvial and lacustrine carbonates of Fish Lake Valley (FLV). Whereas both the VB (near present-day Reno) and CB (southern Owens Valley) receive input of water directly from the Sierra crest, FLV is a region of proposed reconvergence of moisture in the Basin and Range. The oxygen isotope records in both CB and FLV increase during the Neogene by approximately 2 ‰, while the hydrogen isotope record of the VB decreases by distillation. A Neogene pulse of uplift in the southern Sierra could have driven modern flow around the High Sierra, increasing δ18O values in CB and FLV while simultaneously decreasing those of the VB. Future paleoaltimetry studies should evaluate the potential

  9. Lower Paleogene Tectonostratigraphy of Balochistan: Evidence for Time-Transgressive Late Paleocene-Early Eocene Uplift

    Directory of Open Access Journals (Sweden)

    William C. Clyde


    Full Text Available Analysis of lithofacies, paleoflow directions, and sandstone petrography of upper Paleocene-lower Eocene paralic and continental sediments exposed along the transpressional suture zone of the western margin of the Indian plate indicate that the process of deformation and uplift of the carbonate shelf in this area had started by late Paleocene time. This tectonic uplift and deformation is documented by: (1 an overall shallowing upward synorogenic sequence of sediments, (2 proximal conglomerate facies (consisting of lower Paleocene and Mesozoic clasts dominating in the western part of the study area and distal facies of sandstone and shale dominating in the eastern part of the study area, (3 the existence of an unconformity of late Paleocene-early Eocene age in the Quetta and Kalat regions, (4 paleocurrent directions in deltaic and fluvial deposits indicating southeastward flowing sediment dispersal paths during late Paleocene-early Eocene time, which is opposite to that found in the late Cretaceous, suggesting a reversal in the depositional slope of the Cretaceous shelf, and (5 petrographic study of sandstones indicating a collision suture/fold thrust belt provenance. This episode of uplift and deformation could be the result of India-Arabian transpression with associated ophiolite obduction or, more likely, to represent the local response to initial India-Asia contact. The unroofing pattern and uplift geometry of the western Indian shelf suggests that this tectonism first started in the southern part of the study area (Kalat-Khuzdar area during the late Paleocene-early Eocene and proceeded northward in a time-transgressive fashion.

  10. A hydromechanical approach to assess CO2 injection-induced surface uplift and caprock deflection


    Li, Chao; Laloui, Lyesse; Barès, Paul


    This study focuses on the derivation of a semi-analytical approach for the evaluation of surface uplift and caprock deflection induced by underground injection of CO2. The adopted methodology includes the development of a mathematical model that incorporates the deformable behaviour of the storage reservoir and the flow of two immiscible fluids (CO2 and brine) within the aquifer while the surface rock or the caprock layer is modelled as a thin plate. Governing equations are solved for the axi...

  11. 10D massive type IIA supergravities as the uplift of parabolic M2-brane torus bundles

    Energy Technology Data Exchange (ETDEWEB)

    Garcia del Moral, Maria Pilar [Universidad de Antofagasta (Chile). Dept. de Fisica; Restuccia, Alvaro [Universidad de Antofagasta (Chile). Dept. de Fisica; Universidad Simon Bolivar, Caracas (Venezuela, Bolivarian Republic of). Dept. de Fisica


    We remark that the two 10D massive deformations of the N = 2 maximal type IIA supergravity (Romans and HLW supergravity) are associated to the low energy limit of the uplift to 10D of M2-brane torus bundles with parabolic monodromy linearly and non-linearly realized respectively. Romans supergravity corresponds to M2-brane compactified on a twice-punctured torus bundle. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Detection of near-surface horizontal anisotropy in a weathered metamorphic schist at Llano Uplift (Texas) by transient electromagnetic induction (United States)

    Collins, Jamie L.; Everett, Mark E.; Johnson, Brann


    The use of transient controlled-source electromagnetic prospecting to detect buried, steeply dipping foliation in metamorphic rocks is illustrated with data acquired over the Precambrian Packsaddle schist in the Llano Uplift of central Texas. The azimuthal variation of the transient voltage at a given transmitter-receiver separation about a fixed central point is consistent with the forward model response of a homogeneous halfspace exhibiting horizontal electrical anisotropy. The loop-loop exploration configuration is ideally suited to probe horizontal anisotropy. A quantitative match of the forward response to the observed data produces reasonable electrical conductivity values and coefficient of anisotropy for resistive, crystalline geological materials. The most conductive direction consistently lies within a few degrees of the geologically mapped foliation strike direction. The electrical anisotropy is strongest below the near-surface weathered layer, within the more competent bedrock. The agent responsible for generating the anistropy cannot be definitively determined, because it is likely to be a combination of geological factors, such as weathering, compositional banding and microcracking, all of which enhance electrical conductivity parallel to the plane of foliation. The transient electromagnetics is supplemented by DC resistivity and seismic surveys. The elastic anisotropy is evident in the near-surface weathered layer, but it may not persist very deep into the underlying competent schist. The exposure of foliated schist at the surface is not sufficient to rule out a possible role for systematically aligned macrofracture sets as a secondary cause of the observed anisotropy.

  13. Upliftment Estimation of the Zagros Transverse Fault in Iran Using Geoinformatics Technology

    Directory of Open Access Journals (Sweden)

    Biswajeet Pradhan


    Full Text Available The Izeh fault zone is a transverse fault zone with dextral strike slip (and some reverse component in the Zagros Mountains (Iran. It causes some structural deformations. This fault zone is acting as eastern boundary of Dezful Embayment and forms subsidence of the embayment. The fault has been recognized using remote sensing techniques in conjunction with surface and subsurface analyses. The stratigraphic columns have been prepared in 3D form using Geographical Information System (GIS tools on the basis of structural styles and thickness of lithologic units. Height differences for erosion levels have been calculated in stratigraphic columns with respect to the subsidence in the Dezful Embayment, which is related to Izeh zone. These height differences have been estimated to be 5,430 m in the central part (and 5,844 m in the northern part from the Eocene to recent times. This study shows that comparison of the same erosion levels in Asmari-Pabdeh formation boundaries for interior and eastern block of the Izeh fault zone with the absolute uplifting due to the fault activity which is about 533 m per million years in the Izeh zone. The present study reveals that subtracting the absolute uplifting from total subsidence; the real subsidence of Dezful embayment from Eocene to Recent is 0.13 mm/year. The mean rate of uplifting along the Izeh fault zone is 0.015 mm/year.

  14. Paleo-heat flow evolution of the Tabei Uplift in Tarim Basin, northwest China (United States)

    Li, Meijun; Wang, Tieguan; Chen, Jianfa; He, Faqi; Yun, Lu; Akbar, Sadik; Zhang, Weibiao


    The paleo-heat flow evolution of the Tabei Uplift in the Tarim Basin is investigated based on burial and thermal history reconstruction of 14 wells and using basin modeling. Numerous geological parameters, such as, temperature data and missing sediment thickness by erosion were used in the modeling. The basin model was calibrated using 460 measured vitrinite reflectance (% VRo) and vitrinite-like maceral reflectance (% VLMRo) values to constrain the validity of the maturity model. The heat flow history of the Tabei Uplift, Tarim Basin shows the following characteristics: (1) the highest paleo-heat flow was predicted to have occurred in the Early Ordovician as 65 ± 5 mW/m 2, and gradually decreased to 55 ± 5 mW/m 2 during the Late Carboniferous; (2) a thermal kick was modeled to have occurred in the Permian as suggested by an abrupt rise in the heat flow; (3) the heat flow gradually decreased since the Triassic; (4) the present day heat flow was predicted to be as low as 38 mW/m 2. This heat flow history honors the geologic and tectonic evolution history of the Tabei Uplift and is suggested as the best case heat flow model.

  15. A 17-My-old whale constrains onset of uplift and climate change in east Africa. (United States)

    Wichura, Henry; Jacobs, Louis L; Lin, Andrew; Polcyn, Michael J; Manthi, Fredrick K; Winkler, Dale A; Strecker, Manfred R; Clemens, Matthew


    Timing and magnitude of surface uplift are key to understanding the impact of crustal deformation and topographic growth on atmospheric circulation, environmental conditions, and surface processes. Uplift of the East African Plateau is linked to mantle processes, but paleoaltimetry data are too scarce to constrain plateau evolution and subsequent vertical motions associated with rifting. Here, we assess the paleotopographic implications of a beaked whale fossil (Ziphiidae) from the Turkana region of Kenya found 740 km inland from the present-day coastline of the Indian Ocean at an elevation of 620 m. The specimen is ∼ 17 My old and represents the oldest derived beaked whale known, consistent with molecular estimates of the emergence of modern strap-toothed whales (Mesoplodon). The whale traveled from the Indian Ocean inland along an eastward-directed drainage system controlled by the Cretaceous Anza Graben and was stranded slightly above sea level. Surface uplift from near sea level coincides with paleoclimatic change from a humid environment to highly variable and much drier conditions, which altered biotic communities and drove evolution in east Africa, including that of primates.

  16. Slope-area and stream length index analysis in the eastern Tennessee seismic zone: evidence for differential uplift? (United States)

    Stearns, C.; Arroucau, P.; Vlahovic, G.


    Previous studies have shown that Digital Elevation Model (DEM) analysis could be used to quantify surface deformation in tectonically active regions, including slowly deforming areas such as intraplate continental interiors. Here, we investigate slope/area relationships and determine stream length index (SLI) spatial variations in 287 watersheds located in the Valley and Ridge physiographic province of the southern Appalachians, in a region known as the eastern Tennessee seismic zone (ETSZ). The goal is to identify possible spatial variations in drainage network characteristics that could reveal different deformation rates and styles within the study area. The ETSZ, although seismically active, does not show any evidence of recent surface deformation that could be related to tectonic activity. The earthquakes mostly occur between 5 and 25 km depth and their epicenters form a SSW-NNE trending, 300 km long by 100 km wide, band of diffuse seismicity that aligns along the New York Alabama (NYAL) magnetic lineament, a linear magnetic feature attributed to a fault affecting the Precambrian basement but without signature at the surface. DEMs with a resolution of 30 meters and watershed boundaries of 287 drainage basins were obtained from the United States Geological Survey (USGS) National Elevation Dataset (NED) and National Hydrography Dataset (NHD), respectively. After determining the local slope and drainage area for each 30 m x 30 m cell, reference concavity and steepness index values were calculated for the entire region. Then, the steepness index of each watershed was determined using the obtained reference concavity index. SLI values were also determined along extracted river profiles and average values calculated for each watershed. A good correlation is observed between steepness index and SLI, with low to mid-range values found in the Valley and Ridge province and higher values in two specific areas: at the transition between the Valley and Ridge province and

  17. Rock uplift and exhumation of continental margins by the collision, accretion, and subduction of buoyant and topographically prominent oceanic crust

    National Research Council Canada - National Science Library

    Spikings, Richard; Simpson, Guy


    .... Here we combine previous thermochronological data with field observations to determine the amount of exhumation, rock, and surface uplift that occurs in the upper plate of Central and South American...

  18. Tectonic Uplift and Fan Delta Incision along the Conway Coast, NZ (United States)

    Burtt, D. G.; Bassett, K. N.


    The Conway Coast features a unique confluence of fan deltas, terrace uplift, and transpressional faulting. Thrust faults have caused the uplift of the Hawkeswood Range which provides sediment sources for local Gilbert-type fan deltas uplifting to form terraces. Sediments are characterized by steeply dipping foreset beds, horizontal topset beds and tangential bottomset beds. These fan deltas tend to form on steep basin margins often associated with extensional faulting. However, the Conway coast is dominated by thrust faulting. The Rafa terrace, dated between 52.4±4.5 and 79.0±3.5 ka with Optically Stimulated Luminescence, is exposed in cliff faces on the beach. Local creek channels deposited the fan deltas and later incised older deposits to reveal a three-dimensional perspective of the fan delta. This perspective is vital to the recreation of the fan delta position and channel avulsion, leading to a better understanding of the role of uplift superimposed by sea level change in the formation of the terraces. Forty-three photographs were stitched together to form an extensive photomosaic. The types of sediments, significant structures and relationships between adjacent beds were noted and analyzed. Correlations between the sedimentary architecture and sea level change were made using a sea level curve of the South Pacific over the last 140 ka. The incision of mud by gravel producing large flame structures suggests that there was a drop in sea level and a subsequent progradation of the fan delta. Based on the sea level curve, this drop occurred between ~66-79 ka. Higher in the fan delta, a fining-upward sequence points to a rise in sea level. This correlates with a rise on the sea level curve between ~52-63 ka. Upsection there is another coarsening-upward sequence of 5-10 m thick beds suggesting a fall in sea level before the uplift and incision of the terrace and the subsequent formation of the Ngaroma terrace. Due to their lateral extent, the gravels seem to

  19. Formation stage and controlling factors of the paleo-uplifts in the Tarim Basin: A further discussion


    Yuan Neng; Guanghui Wu; Shaoying Huang; Xing Zhang; Shujuan Cao


    Various types of paleo-uplifts with different characteristics are developed in the Tarim Basin. Previously, there were multiple opinions on the pale-uplifts origins and structural evolution, so the oil and gas exploration ideas and deployment in the Tarim Basin were not developed smoothly. In this paper, regional seismic interpretation and structural analysis were carried out on the deep marine carbonate rocks in this basin based on the new seismic and drilling data. Then combined with the st...

  20. Atmospheric CO2 Consumption in Uplifting Mountain Ranges: New Insight From the New Zealand Southern Alps (United States)

    Jacobson, A. D.; Blum, J. D.; Chamberlain, C. P.


    Rates of physical erosion and chemical weathering in uplifting mountain ranges are generally higher than the rates observed in tectonically stable regions. This observation has led to the hypothesis that orogenic events lead to global cooling over geologic time scales by accelerating the rate of atmospheric CO2 drawdown from silicate weathering. However, recent studies of rivers draining the rapidly uplifting Himalaya Mountains have demonstrated that much of the chemical weathering flux is dominated by carbonate dissolution, which does not influence long-term atmospheric CO2 levels. To examine if carbonate weathering dominates in other orogenic environments, we have undertaken investigations of rivers draining the New Zealand Southern Alps, which present a largely unexplored setting for systematically examining tectonic controls on the carbon cycle. In particular, we quantified rates of physical erosion and both silicate and carbonate weathering across a gradient of variable uplift rates but constant bedrock composition. We also compared the findings to global mean values as well as to data for major world rivers in other tectonic and climatic settings. Rapid uplift in the western Southern Alps elevates mechanical erosion rates by a factor of ~13 relative to those on the tectonically stable eastern side. Similarly, the average chemical weathering rate is ~5 times higher on the western compared to eastern side of the mountain range. However, because the proportion of stream-water Ca2+ and Mg2+ from the weathering of trace hydrothermal calcite increases as the rate of mechanical erosion increases, the long-term atmospheric CO2 consumption rate on the western side is only ~2 times higher than that on the eastern side and only ~1.5 times higher than the global mean value. These data demonstrate that tectonic uplift in the New Zealand Southern Alps accelerates physical erosion and chemical weathering rates but does not greatly enhance the rate of long-term atmospheric


    National Research Council Canada - National Science Library

    Thomas K Grose


      Inspired by Star Trek turbolifts, German engineering firm ThyssenKrupp says it's ready to replace cables and pulleys using maglev, or magnetic levitation technology, that enables the world's fastest...

  2. Morpho-Tectonic Evidence of Multi-Stage Uplift History of the Southeastern Ethiopian Plateau, the East African Rift System (United States)

    Xue, L.; Abdelsalam, M. G.


    We used Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) to extract geomorphic proxies (normalized steepness, stream length gradient, shape factor, and valley height ratio) for the Southwestern Ethiopian Plateau. We also imaged the Moho beneath the plateau using two-dimensional power radially-average power spectral analysis of World Gravity Model (WGM 2012) satellite gravity data. Our aim is to examine the uplift history of the plateau that might be associated with the uprising of the Afar mantle plume and opening of the East African Rift System. This plateau, which is bounded by the Afar Depression in the north and the Main Ethiopian Rift in the east, exposes Cenozoic volcanic rocks at the top underlain by Mesozoic sedimentary rocks. Studies in the Northwestern Ethiopian Plateau resulted in two contrasting models for explaining the uplift history of the region. Thermogeochronology studies suggest a continuous and steady uplift rate since 30 Ma possibly driven by the ascending Afar mantle plume. While, the interpretation of incision of drainage systems in the plateau suggests three stage and accelerated uplift. Our work found two areas with high rate of tectonic uplift located around the Mendebo and the Ahmar mountains. These regions show two distinct phases of uplift of the Southeastern Ethiopian Plateau. Also, a chronological framework has been provided to the knickpoint migration and associated Quaternary basalt event by knickpoint celerity model.

  3. Relaxation of continental lithosphere: An explanation for Late Cretaceous reactivation of the Sabine Uplift of Louisiana-Texas (United States)

    Nunn, Jeffrey A.


    With few unconstrained assumptions, a simple quantitative model for flexural isostasy between two crustal blocks of different thickness that subsequently undergoes partial relaxation of accumulated stress can explain reactivation of the Sabine Uplift in the mid-Cretaceous. Thin salt over the Sabine Uplift indicates that it was a positive area in the Middle Jurassic but began to subside during the Late Jurassic. During the Late Jurassic and Early Cretaceous, the Sabine Uplift had no topographic expression and was the center of a large, flat bottomed basin covering most of east Texas and north Louisiana. Reactivation of the Sabine Uplift in the mid-Cretaceous caused a minimum of 150 m of uplift and extensive erosion of Lower Cretaceous rocks. During the Late Cretaceous and Tertiary, the Sabine Uplift resumed subsiding but at a slower rate than the adjacent basins. Since the mid-Cretaceous, the Sabine Uplift has risen more than 1 km relative to the East Texas Basin. We suggest that this structural history is consistent with the following simple quantitative model for flexural isostasy. During formation of the Gulf of Mexico in the Late Triassic-Early Jurassic by rifting and extension of the lithosphere, brittle deformation of the crust created small-scale wavelength of tens of kilometers, lateral variations in crustal thickness. Initially, the newly formed margin was in point-wise Airy isostatic equilibrium. Thus synrift and/or early postrift subsidence was characterized by a series of rift valleys or half grabens separated by uplifts. However, as the margin cooled and contracted, the lithosphere became stronger, and subsequent loading was regionally compensated. Thus postrift subsidence was characterized by a broad regional downwarp. If, at some later point in time, the rigid portion of the lithosphere was weakened or relaxed, then lateral density variations would have been recompensated at shorter wavelengths. Thus areas of little or no crustal extension would have

  4. Rock Uplift above the Yakutat Megathrust on Montague Island, Prince William Sound, Alaska (United States)

    Ferguson, K.; Armstrong, P. A.; Haeussler, P. J.; Arkle, J. C.


    The Yakutat microplate is subducting shallowly (~6°) beneath the North American Plate at a rate of approximately 53 mm/yr to the northwest. Deformation from this flat- slab subduction extends >600 km inland and has resulted in regions of focused rock uplift and exhumation in the Alaska Range, central Chugach Mountains, and St. Elias Mountains. Many questions still remain about how strain is partitioned between these regions of focused uplift, particularly in the Prince William Sound (southern Chugach Mountains) on Montague Island. Montague Island (and adjacent Hinchinbrook Island) are ~20 km above the megathrust where there is a large degree of coupling between the subducting Yakutat microplate and overriding North American Plate. Montague Island is of particular interest because it lies between two areas of rapid rock uplift focused in the St. Elias/eastern Chugach Mountains and the western Chugach Mountains. In the St. Elias/eastern Chugach Mountains, faulting related to collisional processes and bending of fault systems causes rapid rock uplift. About 200 km farther northwest in the western Chugach Mountains, recent rock uplift is caused by underplating along the megathrust that is focused within a syntaxial bend of major fault systems and mountain ranges. Montague Island bounds the southern margin of Prince William Sound, and is steep, narrow, and elongate (81 km long and ~15 km wide). The maximum relief is 914 m, making for very steep, mountainous topography considering the narrow width of the island. During the Mw 9.2 earthquake in 1964, the Patton Bay and Hanning Bay reverse faults were reactivated, with 7 and 5 m of vertical offset, respectively. Both faults dip ~60° NW and strike NE-SW parallel to the long-axis of the island and parallel to geomorphic features including lineaments, elongate valleys, and escarpments. Prominent ~450 m high escarpments are present along the SE-facing side of the island, which suggests rapid and sustained uplift. New apatite

  5. Plate-mantle interaction through time explains two-phase uplift history of the eastern Australian passive margin (United States)

    Dietmar Müller, R.; Flament, Nicolas; Matthews, Kara J.; Williams, Simon E.; Gurnis, Michael


    The origin of passive margin mountains is a hotly debated topic in geodynamics. The Eastern Highlands of Australia are a type example whose uplift history has been investigated for several decades, with suggested mechanisms ranging from flexural rift shoulder uplift, volcanism and underplating to mantle-convection driven dynamic topography. Most of the highlands have experienced a distinct two-phase uplift history, with the first phase being Late Cretaceous in age, followed by a mid-late Cenozoic renewal in uplift, but the timing and magnitude of uplift differs along strike. We investigate the origin of the Eastern Highlands with a coupled plate-mantle model, using a thorough parameter space analysis, including two alternative subduction boundary evolution models. The first model includes a large (~1000 km width at its maximum extent) Early Cretaceous (140-120 Ma) back-arc basin east of the Lord Howe Rise, representing the now subducted South Loyalty Basin which may have formed due to eastward rollback of the long-lived west-dipping eastern Gondwanaland subduction zone; the alternative scenario is based on the premise that west-dipping subduction is continuous to the East of the Lord Howe Rise between 140-85 Ma, without a large back-arc basin, and the South Loyalty Basin opening as a back arc basin from 85-55 Ma, which is subsequently consumed by subduction. We further investigate the influence of a low-viscosity asthenosphere and of the viscosity profile of the lower mantle on dynamic topography, as well as the effect of changing the buoyancy of the basal dense layer (LLSVP) that contributes to the long-wavelength Pacific superswell. Our best-fit model produces a total uplift up to ~400 m in the interval between 120 and 90-70 Ma, well-matched with recent published estimates from river profile inversion for the Snowy Mountains, New England and the Central Highlands. The driving mechanism is rebound from the eastwards motion of Australia over a sinking slab, first

  6. Deep intrusions, lateral magma transport and related uplift at ocean island volcanoes (United States)

    Klügel, Andreas; Longpré, Marc-Antoine; García-Cañada, Laura; Stix, John


    Oceanic intraplate volcanoes grow by accumulation of erupted material as well as by coeval or discrete magmatic intrusions. Dykes and other intrusive bodies within volcanic edifices are comparatively well studied, but intrusive processes deep beneath the volcanoes remain elusive. Although there is geological evidence for deep magmatic intrusions contributing to volcano growth through uplift, this has rarely been demonstrated by real-time monitoring. Here we use geophysical and petrological data from El Hierro, Canary Islands, to show that intrusions from the mantle and subhorizontal transport of magma within the oceanic crust result in rapid endogenous island growth. Seismicity and ground deformation associated with a submarine eruption in 2011-2012 reveal deep subhorizontal intrusive sheets (sills), which have caused island-scale uplift of tens of centimetres. The pre-eruptive intrusions migrated 15-20 km laterally within the lower oceanic crust, opening pathways that were subsequently used by the erupted magmas to ascend from the mantle to the surface. During six post-eruptive episodes between 2012 and 2014, further sill intrusions into the lower crust and upper mantle have caused magma to migrate up to 20 km laterally, resulting in magma accumulation exceeding that of the pre-eruptive phase. A comparison of geobarometric data for the 2011-2012 El Hierro eruption with data for other Atlantic intraplate volcanoes shows similar bimodal pressure distributions, suggesting that eruptive phases are commonly accompanied by deep intrusions of sills and lateral magma transport. These processes add significant material to the oceanic crust, cause uplift, and are thus fundamentally important for the growth and evolution of volcanic islands. We suggest that the development of such a magma accumulation zone in the lower oceanic crust begins early during volcano evolution, and is a consequence of increasing size and complexity of the mantle reservoir system, and potentially

  7. Tracing Altiplano-Puna plateau surface uplift via radiogenic isotope composition of Andean arc lavas (United States)

    Scott, E. M.; Allen, M. B.; Macpherson, C.; McCaffrey, K. J. W.; Davidson, J.; Saville, C.


    We have compiled published geochemical data for Jurassic to Holocene Andean arc lavas from 5oN to 47oS, covering the current extent of the northern, central and southern volcanic zones. Using this dataset we evaluate the spatial and temporal evolution of age corrected Sr- and Nd-radiogenic isotopes in arc lavas at a continental-scale, in order to understand the tectonic and surface uplift histories of the Andean margin. It has long been noted that baseline 87Sr/86Sr and 143Nd/144Nd ratios of Quaternary lavas from the central volcanic zone, located within the Altiplano-Puna plateau, are distinct from volcanic rocks to the north and south. This is commonly attributed to greater crustal thickness, which increases to roughly twice that of the average continental crust within the Altiplano-Puna plateau. By comparing 87Sr/86Sr and 143Nd/144Nd ratios in Quaternary lavas to published crustal thickness models, present day topography and the compositions of basement terranes, we note that Sr- and Nd-isotope values of Quaternary lavas are an effective proxy for present day regional elevation. In contrast, variation in basement terranes has only a small, second order effect on isotopic composition at the scale of our study. Using this isotopic proxy, we infer the spatial extent of the plateau and its surface uplift history from the Jurassic to the present. Our results concur with a crustal thickening model of continued surface uplift, which initiated in the Altiplano, with deformation propagating southwards into the Puna throughout the Neogene and then continuing in central Chile and Argentina up to the present day.

  8. Post-orogenic subsidence and uplift of the Carpathian belt: An integrated approach (United States)

    Bertotti, G.; Matenco, L.; Drijkonigen, G.; Krijgsman, W.; Tarapoanca, M.; Panea, I.; Vasiliev, I.; Milea, M.; Cloetingh, S.


    Several hundred metres thick Pliocene to Quaternary sequences outcropping along the Carpathian front steeply dip away from the mountain belt towards the Carpathian foredeep. They overly the Carpathian fold-and-thrust belt and document that, following the main contractional stages, the orogenic wedge first subsided and was then uplifted. Uplift occurred coeval with substantial subsidence in the basin adjacent to the E, the Focsani Depression. To define the precise kinematics of such movements and thereby constrain these vertical movements taking place in the "wrong" place and in the "wrong" time, the Netherlands Research Center for Integrated Solid Earth Science has launched a large campaign of geological and geophysical investigation. The main components of the project are as follows: 1) acquisition of nearly 100km of seismic data designed to image the uppermost hundred metres of the Earth's crust and thereby making a precise connection between features visible in Industry lines and at the surface 2) paleomagnetic investigations in order to constrain the age of the poorly dated continental to lacustrine sediments 3) A seismic experiment designed to detect 3-D effects on 2-D acquisition 4) Structural work to determine the stress/strain conditions during subsidence and subsequent uplift At a larger scale, these activities are embedded in the effort made by ISES and connected groups to precisely constrain the kinematics of the Pannonian-Carpathian system. Seismic acquisition has been performed during the summer 2002 and has been technically very successful thanks also to the effort of the prospecting company Prospectiunii SA. Lines have been processed and are currently being interpreted. The most apparent feature is the lack of localized deformation demonstrating that subsidence and tilting affected areas of several tens of kilometers and are not related to single faults. Sampling for paleomagnetic studies has been carried out in 2002 along the same section where

  9. Primary succession and dynamics of Norway spruce coastal forests on land-uplift ground moraine

    Energy Technology Data Exchange (ETDEWEB)

    Svensson, J.S.; Jeglum, J.K. [Swedish Univ. of Agricultural Sciences, Umeaa (Sweden). Dept of Forest Ecology


    This paper is an overview of primary succession on the rising coastlines of the Gulf of Bothnia, which emphasises Norway spruce succession and forest development and identifies topics for research. It is concluded that continuing postglacial rebound provides excellent successional sequences, and an exceptional opportunity to add new and important knowledge on original forest ecosystem development. First, long-term undisturbed forest seres, terminating in climax-like Norway spruce forest, exist. Secondly, a well-stocked, old growth spruce forest can develop on the (generally) fairly productive mesic ground-moraine sites in a short ecological time. Thirdly, undisturbed successional sequences, which go back to original soil formation, permit reconstruction of ecosystems' developmental history. Fourthly, the relationship between ground elevation and land-uplift rate facilitates estimates of ground age, and consequently permits a four-dimensional study approach. Fifthly, in view of extensive anthropogenic influence in boreal Fennoscandian forests, the few remaining natural spruce forests should be recognised and carefully documented. From our review of the literature, we conclude that present knowledge of the succession of Norway spruce on emerging shorelines, and the part played by land uplift and other factors, is fragmentary. Attention should be given to initial spruce seedling colonisation relative to factors such as sea-water level, exposure (winds, fetch), parent material, seedbed types, potential seed source (isolation), and island size. Possible multiple pathways of Norway spruce primary succession relative to temporal changes in exposure and other factors, have so far received little research effort. Attention also should be paid to the response of spruce populations to site maturation, i.e. to increasing ground age based on land-uplift rate and elevation above sea level. Finally, attention should be paid to autogenic processes in spruce-dominated stages

  10. Seafloor Uplift in Middle Valley, Juan de Fuca Ridge: New High-Resolution Pressure Data (United States)

    Inderbitzen, K. E.; Becker, K.; Davis, E. E.


    Currently, in-situ seafloor and basement pressures are continuously monitored and recorded by an ODP subseafloor hydrogeological observatory (CORK) located in Middle Valley, Juan de Fuca Ridge. Hole 857D was drilled in 1991 in thickly sedimented crust to a depth of 936 mbsf and instrumented with an original CORK that was replaced in 1996. A large hydrothermal field (Dead Dog) lies roughly 1.7 km north of the hole, and two isolated chimneys and several diffuse flow sites are located ~800 meters northeast. The borehole and the vent fields have been visited periodically by submersible/ROV since 1999. Recent results from the CORK at 857D have shown apparent seafloor uplift, supported by depth records from the submersible Alvin. A constant rate of pressure change of ~6 kPa/yr, from its initiation in 2005 to the visit in 2010, has reduced mean seafloor pressure by ~28 kPa, equivalent to nearly 3 meters of head. This uplift rate is several times the typical pre-eruption inflation rates observed at Axial Seamount further south along the Juan de Fuca Ridge. Initially, the apparent uplift at 857D did not seem to have any effect on local high-temperature hydrothermal venting, however recent operations in Middle Valley revealed distinct changes at not only the hydrothermal field to the northeast, but also a shutdown of high-temperature venting to the north of 857D. We will present new data from Middle Valley, including the first year of data collected by a high-resolution pressure data logger deployed at 857D in June, 2010.

  11. Gold-quartz vein deposition in an uplifted blueschist terrane, Seward Peninsula, Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Read, J.J.


    The Big Hurrah mine, located on the Seward Peninsula, Alaska, consists of gold-quartz-carbonate veins which cut sheared carbonaceous metasedimentary and metavolcanic rocks. The rocks underwent regional syn-kinematic blueschist facies metamorphism in the Jurassic. Glaucophane in metabasite and mafic and pelitic schists has been reported from the central Seward Peninsula. Chlorite+/-epidote+/-albite+/-paragonite pseudomorphs after lawsonite and glaucophane have also been reported. The replacement of these blueschist facies minerals probably occurred during uplift and retrogradation of the terrane. The veins at Big Hurrah range from early, concordant metamorphic quartz lenses to discordant tension veins to discontinuous quartz-Au lodes which occur in sheared zones cross-cutting the foliation. The veins are thought to have formed during the late stages of shearing and uplift. Fluid inclusions in the veins are similar to those found in metamorphic rocks in that they are small, most are secondary, and may contain CO/sub 2/ and CH/sub 4/. The is evidence for CO/sub 2/-CH/sub 4//H/sub 2/O liquid immiscibility. Pressure estimates of 0.8 kbar were calculated from coexisting CO/sub 2/-CH/sub 4/ and aqueous inclusions. Pressure corrected homogenization temperatures for quartz deposition are in the range 300-400/sup 0/C. Hence, the veins were deposited at lower pressures and temperatures than those of the blueschist facies event. It is thought that the veins at Big Hurrah were formed during uplift by a fluid phase derived by metamorphic dehydration and channeled into conduits depositing quartz, carbonate and gold.

  12. Heating, cooling, and uplift during Tertiary time, northern Sangre de Cristo Range, Colorado ( USA). (United States)

    Lindsay, D.A.; Andriessen, P.A.M.; Wardlaw, B.R.


    Paleozoic sedimentary rocks in a wide area of the northern Sangre de Cristo Range show effects of heating during Tertiary time. Heating is tentatively interpreted as a response to burial during Laramide folding and thrusting and also to high heat flow during Rio Grande rifting. Fission-track ages of apatite across a section of the range show that rocks cooled abruptly below 120oC, the blocking temperature for apatite, approx 19 Ma ago. Cooling was probably in response to rapid uplift and erosion of the northern Sangre de Cristo Range during early Rio Grande rifting.-from Authors

  13. Deformation and failure mechanism of excavation in clay subjected to hydraulic uplift

    CERN Document Server

    Hong, Yi


    This book presents the latest experimental and numerical analysis work in the field of ground deformation and base instability of deep excavations in soft clay subjected to hydraulic uplift. The authors’ latest research findings, based on dimensional analyses, well-instrumented full-scale field tests, systematic coupled-consolidation finite element analyses and centrifuge tests are reported. This book shows how to systematically approach a complex geotechnical problem, from identifying existing problems, reviewing literature, to dimensional and numerical analyses, validation through full-scale testing and centrifuge model testing. The methodologies are also introduced as major tools adopted in geotechnical research.

  14. Transient uplift after a 17th-century earthquake along the Kuril subduction zone. (United States)

    Sawai, Yuki; Satake, Kenji; Kamataki, Takanobu; Nasu, Hiroo; Shishikura, Masanobu; Atwater, Brian F; Horton, Benjamin P; Kelsey, Harvey M; Nagumo, Tamotsu; Yamaguchi, Masaaki


    In eastern Hokkaido, 60 to 80 kilometers above a subducting oceanic plate, tidal mudflats changed into freshwater forests during the first decades after a 17th-century tsunami. The mudflats gradually rose by a meter, as judged from fossil diatom assemblages. Both the tsunami and the ensuing uplift exceeded any in the region's 200 years of written history, and both resulted from a shallow plate-boundary earthquake of unusually large size along the Kuril subduction zone. This earthquake probably induced more creep farther down the plate boundary than did any of the region's historical events.

  15. Phanerozoic burial, uplift and denudation of the Equatorial Atlantic margin of South America (United States)

    Japsen, Peter; Bonow, Johan M.; Green, Paul F.; dall'Asta, Massimo; Roig, Jean-Yves; Theveniaut, Hervé


    We have initiated a study aimed at understanding the history of burial, uplift and denudation of the South American Equatorial Atlantic Margin (SAEAM Uplift) including the Guiana Shield to provide a framework for investigating the hydrocarbon prospectivity of the offshore region. We report first results including observations from fieldwork at the northern and southern flank of the Guiana Shield. The study combines apatite fission-track analysis (AFTA) and vitrinite reflectance data from samples of outcrops and drillcores, sonic velocity data from drill holes and stratigraphic landscape analysis (mapping of peneplains) - all constrained by geological evidence, following the methods of Green et al. (2013). The study will thus combine the thermal history from AFTA data with the denudation history from stratigraphic landscape analysis to provide magnitudes and timing of vertical movements (Japsen et al. 2012, 2016). Along the Atlantic margin of Suriname and French Guiana, tilted and truncated Lower Cretaceous strata rest on Precambrian basement (Sapin et al. 2016). Our AFTA data show that the basement underwent Mesozoic exhumation prior to deposition of the Lower Cretaceous cover. Sub-horizontal peneplains define the landscape of the Guiana Shield at elevations up to 500 m a.s.l. As these sub-horizontal peneplains truncate the tilted, sub-Cretaceous surface along the Atlantic margin, these peneplains were therefore formed and uplifted in post-Cretaceous time. This interpretation is in good agreement with our AFTA data that define Paleogene exhumation along the margin and with the results of Theveniaut and Freyssinet (2002) who used palaeomagnetic data to conclude that bauxitic surfaces across basement at up to 400 m a.s.l. on the Guiana Shield formed during the Palaeogene. Integration of the results from AFTA with stratigraphic landscape analysis (currently in progress) and geological evidence will provide a robust reconstruction of the tectonic development of the

  16. Rapid bedrock uplift in the Antarctic Peninsula explained by viscoelastic response to recent ice unloading

    DEFF Research Database (Denmark)

    Nield, Grace A.; Barletta, Valentina Roberta; Bordoni, Andrea


    Since 1995 several ice shelves in the Northern Antarctic Peninsula have collapsed and triggered ice-mass unloading, invoking a solid Earth response that has been recorded at continuous GPS (cGPS) stations. A previous attempt to model the observation of rapid uplift following the 2002 breakup......×1017–2×1018 Pas – much lower than previously suggested for this region. Combining the LARISSA time series with the Palmer cGPS time series offers a rare opportunity to study the time-evolution of the low-viscosity solid Earth response to a well-captured ice unloading event....

  17. Denudation and uplift history of the Jameson Land basin, East Greenland—constrained from maturity and apatite fission track data (United States)

    Mathiesen, Anders; Bidstrup, Torben; Christiansen, Flemming G.


    The Jameson Land basin in East Greenland comprises a well exposed succession of Upper Paleozoic-Mesozoic sediments. During Middle Devonian-Early Permian rifting, ˜13 km of continental clastics were deposited. In latest Paleozoic to Mesozoic times, ˜4 km of sediments accumulated during regional subsidence. In the Early Paleocene, during North Atlantic break-up, the basin was covered by a thick volcanic pile. Subsequently, uplift and erosion took place over the whole region. The volcanic cover was completely removed from Jameson Land and erosion cut deeply into the underlying sediments. To assess the exploration potential of Jameson Land, a basin modelling study with 21 1D pseudo-wells was carried out based on all seismic and surface data available. In addition to the calculation of hydrocarbon generation in space and time, the basin modelling provided an opportunity to study the magnitude and timing of uplift and erosion. Basin modelling constrained by apatite fission track data has made it possible to determine a consistent uplift and erosion history of the area. Tectonic backstripping based on a simple Airy type isostatic model has been used to separate the tectonic uplift from the actual uplift. The combined basin modelling and backstripping study has led to the following conclusions: (1) the thickness of the Cretaceous succession varied from 1.3 km in the south to 0.3 km in the north; (2) the volcanic rocks formed a wedge with a thickness of >2 km in the south thinning to <0.1 km in the north; (3) the subsequent erosion of 2-3 km is in response to tectonic uplift with a magnitude of ˜1 km, and the calculated tectonic uplift shows increasing values to the north. The erosion rate generally accelerated from Late Paleocene up to the present time.

  18. Oil and gas accumulations in the Ordovician carbonates in the Tazhong Uplift of Tarim Basin, west China

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Xiu-Xiang; Jin, Zhi-Jun [Key Laboratory for Petroleum Accumulation in Petroleum University, Ministry of Education, Changping, Beijing 102249 (China); Liu, Luo-Fu; Xu, Shi-Lin [Basin and Reservoir Research Center, University of Petroleum, Changping, Beijing 102249 (China); Zhou, Xin-Yuan; Pi, Xue-Jun; Yang, Hai-Jun [Tarim Oil Field Company, Kurle, Xinjiang 841000 (China)


    Oil and gas fields of the Paleozoic cratonic basin in Tarim are mainly distributed in the Tabei and the Tazhong Uplifts. In the Tazhong Uplift, there are three sets of oil and gas stratum systems, of which the Ordovician traps are the largest in size and close to oil source beds with the most favorable conditions to form large-scale oil and gas fields. The Ordovician sediments in the Tazhong Uplift have experienced a stable platform and tableland margin development period. The Ordovician is divided into mudstone interval, interbedded mudstone and limestone interval, limestone interval, limestone and dolomite transitional interval and dolomite interval. Of these intervals, both interbedded mudstone and limestone interval and limestone interval contain source rocks, while limestone interval and dolomite interval are reservoir beds. Fault activities and denudation have an obvious impact on carbonate rock reservoirs. The major Ordovician trap types of the Tazhong Uplift include compressional fault block, fault anticline and buried hill, and regionally. The Tazhong Uplift can be generally divided into central fault horst trap belt, northern slope trap belt and southern slope trap belt. In view of the in-situ oil source in the Tazhong, oil and gas migration in the Tazhong Uplift is characterized by a short distance migration through sand bodies and unconformity surfaces laterally and along faults vertically. Based on this study, it is concluded that the favorable oil and gas accumulation zone should be the northern slope and the northwestern pitchout end of the uplift because these areas are located in the hydrocarbon migration pathway with weak tectonic activities and favorable preservation conditions.

  19. Land uplift and relative sea-level changes in the Loviisa area, southeastern Finland, during the last 8000 years

    Energy Technology Data Exchange (ETDEWEB)

    Miettinen, A.; Eronen, M.; Hyvaerinen, H. [Helsinki Univ. (Finland). Dept. of Geology


    Southeastern Finland belongs to the area covered by the Weichselian ice sheet, where the release of the ice load caused a rapid isostatic rebound during the postglacial time. While the mean overall apparent uplift is of the order of 2 mm/yr today, in the early Holocene time it was several times higher. A marked decrease in the rebound rate occurred around 8500 BP, however, since then the uplift rate has remained high until today, with a slightly decreasing trend towards the present time. According to current understanding there have neither been temporary increases nor decreases in the rate of uplift during the postglacial time. Even so, it is not known for sure whether there are regional irregularities on the rebound in Finland. Concurrently with land uplift, relative sea-level changes in the Baltic basin were also strongly affected by the global eustatic rise of sea-level. During the early Litorina Sea stage on the southern coast of Finland around 7000 BP, the rise in sea-level exceeded the rate of land uplift, and resulted in a short-lived transgression. The most accurate information on relative sea-level changes in an uplifting area may be obtained from radiocarbon dated events of isolation in small lake basins, as they were cut off from larger bodies of water. The isolations of such basins from the sea may be reliably determined by the recorded changes in the diatom flora in the sediment sequences, at horizons which may be radiometrically dated. In the present study, the isolation-horizons of 13 basins were dated by 26 conventional and 2 AMS radiocarbon dates. According to the available sets of dates, the time span of emergence extends from 8300 BP to the past few hundred years, for lakes from c. 30 m to 1.1 m above the present sea-level. Due to the global rise in sea-level, during the period of 7500-6500 BP, the sea-level rise clearly exceeded the rate of uplift, and resulted in the Litorina transgression, which had an amplitude of around one metre. The

  20. Numerical Study on the Seismic Response of Structure with Consideration of the Behavior of Base Mat Uplift

    Directory of Open Access Journals (Sweden)

    Guo-Bo Wang


    Full Text Available The foundation might be separated from the supporting soil if the earthquake is big enough, which is known as base mat uplift. This paper proposed a simplified calculation model in which spring element is adopted to simulate the interaction between soil and structure. The load-deformation curve (F-D curve of the spring element can be designated to represent the base mat uplift, in which the pressure can be applied while tensile forces are not allowed. Key factors, such as seismic wave types, seismic wave excitation directions, seismic wave amplitudes, soil shear velocities, structure stiffness, and the ratio of structure height to width (H/B, were considered in the analysis. It is shown that (1 seismic wave type has significant influence on structure response due to different frequency components it contained; (2 the vertical input of seismic wave greatly affected structure response in vertical direction, while it has little impacts in horizontal direction; (3 base mat uplift is easier to take place in soil with higher shear velocity; (4 structure H/B value has complicated influence on base mat uplift. The outcome of this research is assumed to provide some references for the seismic design of the structure due to base mat uplift.

  1. Evidence for Late Pleistocene uplift at the Somma-Vesuvius apron near Pompeii (United States)

    Marturano, Aldo; Aiello, Giuseppe; Barra, Diana


    Detailed stratigraphic and micropalaeontological analyses of samples from boreholes at the Somma-Vesuvius apron, between Pompeii and the sea, allowed reconstruction of Late Quaternary palaeoenvironmental evolution of the Sarno coastal plain. In all, 116 samples were recovered from seven boreholes drilled from 2-10 m a.s.l. to 16.5-26 m b.s.l. Microfossil assemblages, with special regard to benthic foraminifers and ostracods, were used to reconstruct the depositional palaeoenvironment. Fossil remains show that all the pre-79 AD fossiliferous sediments from 2 to - 24 m a.s.l. were deposited in shallow marine waters for a long time despite an appreciable sea level rise. The data indicate alternation of both shallow marine and subaerial conditions during the last ~ 15 kyr, evidencing ground uplift of the area of about 75 m at a rate of ~ 5 mm/year. Marine sediment accumulation (~ 6 m/kyr) and tectonic uplift long offset the sea level rise, and as a consequence, submerged areas remained the same as well.

  2. Himalayan uplift shaped biomes in Miocene temperate Asia: evidence from leguminous Caragana. (United States)

    Zhang, Ming-Li; Xiang, Xiao-Guo; Xue, Juan-Juan; Sanderson, Stewart C; Fritsch, Peter W


    Caragana, with distinctive variation in leaf and rachis characters, exhibits three centers of geographic distribution, i.e., Central Asia, the Qinghai-Tibetan Plateau (QTP), and East Asia, corresponding to distinct biomes. Because Caragana species are often ecologically dominant components of the vegetation in these regions, it is regarded as a key taxon for the study of floristic evolution in the dry regions of temperate Asia. Based on an expanded data set of taxa and gene regions from those previously generated, we employed molecular clock and biogeographical analyses to infer the evolutionary history of Caragana and link it to floristic patterns, paleovegetation, and paleoclimate. Results indicate that Caragana is of arid origin from the Junggar steppe. Diversification of crown group Caragana, dated to the early Miocene ca. 18 Ma and onwards, can be linked to the Himalayan Motion stage of QTP uplift. Diversification of the major clades in the genus corresponding to taxonomic sections and morphological variation is inferred to have been driven by the uplift, as well as Asian interior aridification and East Asian monsoon formation, in the middle to late Miocene ca. 12~6 Ma. These findings demonstrate a synchronous evolution among floristics, vegetation and climate change in arid Central Asia, cold arid alpine QTP, and mesophytic East Asia.

  3. Analysis of Causes of Uplift Anomalies in the Čierny Váh Subsoil (United States)

    Bednárová, Emília; Grambličková, Danka; Škvarka, Juraj; Majerčák, Vlastimil; Slávik, Ivan


    The pumped storage hydropower plant of Čierny Váh was created by means of damming up the valley of the Čierny Váh River. The dam is 18.5 m high above terrain and 375 m long in the dam’s crest. Total capacity of the reservoir is 5.1 million m3. Complicated geological conditions in the subsoil of dam’s body – fractured dolomite with local occurrence of tectonic breccia and clays, with the occurrence of intense disturbances - called for the construction of the grouting curtain in the dam’s subsoil. Its depth is about 20 in the area of the riverine plain, and about 60 m in the areas of abutments. During foregoing operations of the structure, more than 30 years, local anomalies in the uplift development in the right abutment’s subsoil of the lower reservoir dam were recorded. Their abnormally high values on the downstream side of grouting curtain have become the subject of extensive discussion and a stimulus for its remediation. To ensure reliable operation of the hydraulic structure a comprehensive analysis of the impact of the long-term operation of the reservoir on the dam safety was carried out. This included an examination of the causes of anomalous development of uplifts using FEM numerical modelling. The paper presents obtained results from this analysis.

  4. Crustal uplift due to ice mass variability on Upernavik Isstrøm, west Greenland

    DEFF Research Database (Denmark)

    Nielsen, Karina; Khan, Shfaqat Abbas; Korsgaard, Niels J.


    from two continuous receivers, UPVK and SRMP which are established on bedrock and located ∼65 and View the MathML source from the front of UI, respectively. We construct along-track elevation changes on UI for several time intervals during 2005–2011, based on ATM, SPOT 5 and Ice, Cloud, and land...... Elevation Satellite (ICESat) data to assess temporal changes of UI. We estimate a mass loss rate of −6.7±4.2 Gt/yr, over an area of View the MathML source. The ice mass loss occurs primarily over the northern glacier of UI. This pattern is also observed View the MathML source upstream, where we observe...... glacier thinning at a rate of −1.6±0.3 m/yr across the northern portion of UI and −0.5±0.1 m/yr across the southern portion. GPS measurements suggest bedrock uplift rates of 7.6±0.6 mm/yr (UPVK) and 16.2±0.6 mm/yr (SRMP). The modeled ice mass loss of UI causes bedrock uplift rates of 1.3±0.6 mm/yr (UPVK...

  5. Uplift history of the Villány Hills (SW Hungary) based on paleontological data (United States)

    Sebe, Krisztina; Pazonyi, Piroska; Gasparik, Mihály; Lajos Szujó, Gábor


    Villány Hills are the southernmost basement outcrop in Hungary, along the northern margin of the Drava Basin. They comprise part of a Cretaceous nappe in the Tisza structural unit. Data on their young tectonic evolution are scarce, mostly due to the almost complete lack of Cenozoic sediments. Though somewhat debated, indirect data suggest that most of the area was covered by Upper Miocene (Lake Pannon) clastic sediments. Uplift and exhumation of the basement was driven by Late Miocene to post-Miocene basin inversion. A unique opportunity to study the uplift history is offered by paleontological data, by small but numerous terrestrial vertebrate sites, which cover a long time span in the Pliocene and Pleistocene. Faunas accumulated in fissure fillings of karstified limestone and thus provide a minimum age for the subaerial exposure (exhumation) of the bedrock at the given site. For some sites it has been proposed that water-linked species in the fauna refer to the existence of an alluvial plain on the clastic cover, in immediate proximity to the bedrock. If true, this would give an exact elevation of the surrounding terrain at the time indicated by the fauna. If exhumation of the basement happened during the time interval covered by the vertebrate faunas, then a relationship is expected to exist between the age and elevation of the the fossil sites, with the youngest faunas lying at lowest elevation. This relationship is expected to be strictly valid primarily in the case of water-linket faunas, but as a trend also for all fossil sites. We collected the age data and ecological requirements of the reliably datable vertebrate faunas and their locations with the possible precision. Then the relationship between the elevation and age was studied and compared to the available geomorphological, sedimentological and tectonic data. The age-elevation distribution of vertebrate faunas did not show the expected relationship. Based on the results, exhumation of the Vill

  6. Constraining Holocene Uplift Rates For The Serrania Del Baudo, Northwestern Colombia, Using Luminescence Dating On A Raised Beach (United States)

    Gonzalez, J.; Shen, Z.; Mauz, B.


    A beach deposit on the southern tip of the Serrania del Baudo, perched 4.5 m above spring high tide, was dated at ~3,000 years using optically stimulated luminescence (OSL) dating. The average uplift rate necessary to raise this deposit is ~1.5 mm/yr. This rate combines the long-term regional deformation associated with the subduction of the Nazca Plate under the South American Plate and the collision of the Choco Block microplate against the South American continent, as well as uplift from local faults. We propose that rapid emergence probably as several pulses, each involving decimeter scale coseismic uplift, is likely to have occurred to elevate the beach above the intertidal zone and offset destructive wave erosion in this sand-limited coast.

  7. Resolving spatial heterogeneities in exhumation and surface uplift in Timor-Leste: Constraints on deformation processes in young orogens (United States)

    Tate, Garrett W.; McQuarrie, Nadine; van Hinsbergen, Douwe J. J.; Bakker, Richard R.; Harris, Ron; Willett, Sean; Reiners, Peter W.; Fellin, Maria Giuditta; Ganerød, Morgan; Zachariasse, Willem Jan


    Although exhumation and surface uplift are important parameters in understanding orogenesis, the opportunity to measure both in close proximity is rare. In Timor-Leste (East Timor), deeply exhumed metamorphic rocks and piggyback deepwater synorogenic basins are only tens of kilometers apart, permitting direct relation of uplift and exhumation by comparing micropaleontology to thermochronology interpreted through one-dimensional thermal modeling. Foraminifera in two deepwater synorogenic basins suggest basin uplift from depths of 1-2 km to depths of 350-1000 m between 3.35 and 1.88 Ma. Thermochronologic sampling was conducted in the central mountain belt between these basins. Of four muscovite 40Ar/39Ar samples, one provides a reset age of 7.13 ± 0.25 Ma in the Aileu high-grade belt that suggests 9-16 km of exhumation since that time. Eighteen zircon (U-Th)/He samples contain a group of reset ages in the Aileu Complex ranging from 4.4 to 1.5 Ma, which suggest exhumation rates of 1.0-3.1 mm/yr with 2.7-7.8 km of exhumation since these ages. Thirteen apatite (U-Th)/He ages in the Gondwana Sequence range from 5.5 to 1.4 Ma, suggesting 1-2 km of exhumation and defining a pattern of exhumation rates (ranging from 0.2 to 1.3 mm/yr) that positively correlates with average annual rainfall. Seven apatite fission track samples display varying degrees of partial resetting, with greatest resetting where apatite (U-Th)/He ages are youngest. Together, these data demonstrate extreme variability in surface uplift and exhumation over small spatial scales. We propose ongoing subsurface duplexing driven by subduction and underplating of Australian continental crust as the predominant driver for surface uplift and uplift-induced exhumation.

  8. Morphometric age estimate of the last phase of accelerated uplift in the Kazdag area (Biga Peninsula, NW Turkey) (United States)

    Demoulin, A.; Altin, T. Bayer; Beckers, A.


    While the Plio-Quaternary uplift of the Kazdag mountain range (Biga Peninsula, NW Turkey) is generally acknowledged, little is known about its detailed timing. Partly because of this lack of data, the cause of this uplift phase is also debated, being associated either to back-arc extension in the rear of the Hellenic subduction zone, to transpression along the northern edge of the west-moving Anatolian microplate, or to extension driven by gravitational collapse. Here, we perform a morphometric study of the fluvial landscape at the scale of the Biga Peninsula, coupling the recently developed R/SR analysis of the drainage network with concavity and steepness measures of a set of 29 rivers of all sizes. While the dependence of profile concavity on basin size confirms that the landscape of the peninsula is still in a transient state, the spatial distribution of profile steepness values characterized by higher values for streams flowing down from the Kazdag massif shows that the latter undergoes higher uplift rates than the rest of the peninsula. We obtain a SR value of 0.324 ± 0.035 that, according to the relation established by Demoulin (2012), yields an age range of 0.5-1.3 Ma and a most probable value of 0.8 Ma for the time of the last tectonic perturbation in the region. In agreement with the analysis of knickpoint migration in a subset of rivers, this suggests that a pulse of uplift occurred at that time and, corroborated by sparse published observations in the Bayramiç and Çanakkale depressions, that the peninsula was uplifted as a whole from that time. This uplift pulse might have been caused by transient compressive conditions in the Anatolian plate when the Eratosthenes seamount came to subduct beneath the Cyprus arc around the early-to-mid Pleistocene transition (Schattner, 2010).

  9. Subduction of the Caribbean Plate and Basement Uplifts in the Overriding South American Plate (United States)

    Kellogg, J. N.; Bonini, W. E.


    The new tectonic interpretations presented in this paper are based on geologic field mapping and gravity data supplemented by well logs, seismic profiles, and radiometric and earthquake data. The present Caribbean-South American plate boundary is the South Caribbean marginal fault, where subduction is indicated by folding and thrusting in the deformed belt and a seismic zone that dips 30° to the southeast and terminates 200 km below the Maracaibo Basin. The Caribbean-South American convergence rate is estimated as 1.9 ± 0.3 cm/yr on the basis of the 390-km length of the seismic zone and a thermal equilibration time of 10 m.y. The Caribbean-South American convergence has produced a northwest-southeast maximum principal stress direction σ1 in the overriding South American plate. The mean σ1 direction for the Maracaibo-Santa Marta block is 310° ± 10° based on earthquake focal mechanism determinations, and structural and gravity data. On the overriding South American plate, basement blocks have been uplifted 7-12 km in the last 10 m.y. to form the Venezuelan Andes, Sierra de Perija, and the Colombian Santa Marta massif. Crystalline basement of the Venezuelan Andes has been thrust to the northwest over Tertiary sediments on a fault dipping about 25° and extending to the mantle. In the Sierra de Perija, Mesozoic sediments have been thrust 16-26 km to the northwest over Tertiary sandstones along the Cerrejon fault. A thrust fault dipping 15° ± 10° to the southeast is consistent with field mapping, and gravity and density data. The Santa Marta massif has been uplifted 12 km in the last 10 m.y. by northwest thrusting over sediments. The basement block overthrusts of the Perijas, Venezuelan Andes, and the Santa Marta massif are Pliocene-Pleistocene analogs for Laramide orogenic structures in the middle and southern Rocky Mountains of the United States. The nonmagmatic basement block uplifts along low-angle thrust faults reveal horizontal compression in the

  10. Diatoms confirm coseismic uplift and subsidence along the eastern Alaska-Aleutian megathrust (United States)

    Dura, T.; Briggs, R. W.; Engelhart, S. E.; Nelson, A. R.; Horton, B.


    The Alaska-Aleutian subduction zone is the source of a series of Mw 8-9.2 20th century ruptures, including the second largest historical earthquake ever recorded in 1964. Paleoseismic studies, employing coastal stratigraphic sequences, have been successfully applied at sites within the 1964 rupture zone, but geologic records are unstudied west of the 1964 rupture. Understanding the behavior of the megathrust is important because a tsunamigenic rupture could damage the west coast of the United States. Investigations in the tidal marshes of Sitkinak Island, off the southwest coast of Kodiak Island, have uncovered stratigraphic evidence of five apparent coseismic land-level changes. Radiocarbon, 210Pb, and 137Cs dating indicate this record may include the 1964 and 1788 earthquakes and some predecessors. Here, we present new paleoecological evidence that independently confirms the inference that at least four of the abrupt lithologic changes in the stratigraphy of Sitkinak Island record coseismic land-level changes. Sudden and lasting changes in fossil diatom assemblages spanning tidal lithologic contacts reveal both coseismic subsidence (mud over peat) and coseismic uplift (peat over mud) during the last 1000 years. Across the contact that may mark the 1964 earthquake, a shift from a brackish, low-marsh diatom assemblage dominated by Diploneis interrupta and Navicula cincta to a tidal flat assemblage containing Actinocyclus normanii and Synedra tabulata indicates a sudden rise in relative sea-level, which we infer to record coseismic subsidence. In contrast, diatoms show evidence of coseismic uplift across the probable 1788 contact. An abrupt transition from a fully marine assemblage containing coastal planktonic and tychoplanktonic taxa to a freshwater marsh assemblage dominated by the salt-intolerant benthic diatom Eunotia fallax is consistent with a sudden and lasting relative sea-level fall. Abrupt changes in lithology across a contact dated about ~575 cal yr

  11. Regional Cenozoic Uplift of Europe from Linear Inverse Modelling of Longitudinal River Profiles (United States)

    McNab, F.; White, N.


    The shape of a river profile is controlled by the interplay between uplift and erosion. It is generally accepted that the phenomenological stream power formulation provides a useful basis for determining how this shape evolves as a function of time and space. Typically, erosion is parametrized using two terms. The first term controls the upstream advection of knickzones and assumes that the advective velocity is a function of upstream drainage area and local slope. The second term controls `rock diffusivity', which acts to lower the river profile. In the geomorphological community, the stream power formulation is usually solved by assuming steady state and by plotting upstream drainage area as a function of slope. Here, we use an integrative approach to solve the equation without the need to assume steady state. Previous work has shown that the `rock diffusivity' term, together with the exponent of local slope (i.e. n), can be ignored at long wavelengths. This simplification enables the linear inverse problem to be posed and solved using the method of characteristics. Large inventories (i.e. thousands river profiles) can be inverted to determine regional uplift rate histories as a function of time and space. We present results from an analysis of a Western Eurasian drainage network, consisting of 1,126 river profiles. This region encompasses at least four areas of high elevation where the origin of topography is much debated (i.e. Scandinavia, Spain, Turkey, Italy). Linear inverse modelling yields excellent fits between observed and calculated river profiles. The key erosional parameters were determined using independent geologic observations (e.g. stratigraphic evidence for marine incursions, emergent marine terraces, thermochronologic constraints). Our results suggest that each of these areas has undergone significant regional uplift in Cenozoic times. Since the linearized approach is computationally efficient, it is possible to systematically test the

  12. Tiotropium as a first maintenance drug in COPD: secondary analysis of the UPLIFT trial

    DEFF Research Database (Denmark)

    Troosters, T; Celli, B; Lystig, T


    The aim of the present study was investigate the long-term effect of tiotropium as first maintenance respiratory medication in chronic obstructive pulmonary disease (COPD). A 4-yr, randomised, multicentre, double-blind, parallel-group, placebo-controlled trial (Understanding Potential Long......-term Impacts on Function with Tiotropium (UPLIFT) was conducted. Analysis focused on the effect of tiotropium versus matching placebo in the 810 (13.5%) COPD patients not on other maintenance treatment (long-acting beta-agonists, inhaled corticosteroids, theophyllines or anticholinergics) at randomisation....... Spirometry, health-related quality of life (St George's Respiratory Questionnaire (SGRQ) score), exacerbations of COPD and mortality were also analysed. 403 patients (mean+/-sd age 63+/-8 yrs, post-bronchodilator forced expiratory volume in 1 s (FEV(1)) 53+/-12% predicted) received tiotropium and 407 (64...

  13. The Higgs vacuum uplifted: revisiting the electroweak phase transition with a second Higgs doublet (United States)

    Dorsch, G. C.; Huber, S. J.; Mimasu, K.; No, J. M.


    The existence of a second Higgs doublet in Nature could lead to a cosmological first order electroweak phase transition and explain the origin of the matter-antimatter asymmetry in the Universe. We explore the parameter space of such a two-Higgs-doublet-model and show that a first order electroweak phase transition strongly correlates with a significant uplifting of the Higgs vacuum w.r.t. its Standard Model value. We then obtain the spectrum and properties of the new scalars H 0, A 0 and H ± that signal such a phase transition, showing that the decay A 0 → H 0 Z at the LHC and a sizable deviation in the Higgs self-coupling λ hhh from its SM value are sensitive indicators of a strongly first order electroweak phase transition in the 2HDM.

  14. Geometry and Kinematics of Tumuxiuke Fold and Thrust Belt in Bachu Uplift, Tarim Basin (United States)

    Song, Z.; Tang, L.


    Bachu uplift, mainly characterized by a series of out-of-sequence basement involved structures, is a large scale Cenozoic structural unit located in the west of Tarim basin. The NW-SE oriented, arc shaped Tumuxiuke fold and thrust belt (TFTB), which is roughly 200km in length, constrains the northern boundary of Bachu uplift. Based on multiple 2D seismic reflection profiles, we analysed the differences in structural styles along the strike of TFTB. It is mainly consist of several basement involved thrust faults and associated folds (or monoclines). The western segment of TFTB is characterized by a single basement involved structure; as to the middle segment, there is also backthrust branching from the main basement involved structure; in contrast, the eastern segment is consist of basement involved contractional wedge structures. According to the analysis of stratigraphy involved in deformation, fault slip and growth strata, we summarized that the TFTB mainly constructed by the compressional stress during late Miocene Himalayan orogency. Then, we analyzed the kinematics of TFTB with trishear fault propagation folding model. It is suggested that the initial fault tip that located below the basement-cover contact began to propagate during the late Miocene epoch and the propagation to slip ratio (P/S) also changes along strike. At the early stage of compression, the P/S was low and sedimentary cover mainly folded; then, the thrust faults of western segment and middle segment propagated rapidly with high P/S ratio and broke through early formed folds into Neogene strata; but in the eastern segment, the main thrust fault pinch out in the thick gypsum salt layer of middle Cambrian and the sedimentary cover decoupled from basement. About the genesis of basement-involved structures of TFTB in the intracontinent circumstance, we consider the effect of positive inversion of late Proterozoic-early Palaeozoic rift which requires further evidences.

  15. Ordovician gas exploration breakthrough in the Gucheng lower uplift of the Tarim Basin and its enlightenment

    Directory of Open Access Journals (Sweden)

    Wang Zhaoming


    Full Text Available A steady high yield natural gas flow was tapped in the Ordovician strata of Well Gucheng 6 drilled in the Gucheng lower uplift in the Tarim Basin in 2012, marking the discovery of another carbonate gas exploration field after the other two fields in the middle and northern Tarim Basin (the so called Tazhong and Tabei in the industry. The exploration in the Gucheng lower uplift has experienced three stages: the first stage, marine facies clastic exploration from 1995 to 2003, focusing on the Devonian Donghe sandstone lithologic traps, the Silurian overlapping lithologic traps, and the Upper Ordovician shelf slope turbidites; the second stage focusing on the reef shoal carbonate reservoirs from 2003 to 2006, during which oil and gas were first discovered in Well Gucheng 4; the third stage can be divided into two periods, in the first period, deeper insight into interbed karstification reservoir exploration, intense research on tricky seismic issues, selection of favorable zones, and 3D seismic deployment in advance laid a robust foundation for breakthroughs in oil and gas exploration; and during 2009–2012, through an in-depth investigation, Well Gucheng 6 was drilled, bringing about the major breakthrough in oil and gas exploration in this study area. This success proves that the Lower Paleozoic carbonate rocks in the Gucheng area have good geological conditions and broad prospect for oil and gas exploration, which give us enlightenment in three aspects: a. new insight into geologic understanding is the prerequisite of exploration breakthrough; b. addressing bottleneck technologies, and acquiring 3D seismic data are the guarantees of exploration breakthrough; and c. emancipation of mind and persistent exploration are key to the findings in new domains.

  16. Rock uplift above the subduction megathrust at Montague and Hinchinbrook Islands, Prince William Sound, Alaska (United States)

    Ferguson, Kelly M.

    Deformation related to the transition from strike-slip to convergent slip during flat-slab subduction of the Yakutat microplate has resulted in regions of focused rock uplift and exhumation. In the St. Elias and Chugach Mountains, faulting related to transpressional processes and bending of fault systems coupled with enhanced glacial erosion causes rapid exhumation. Underplating below the syntaxial bend farther west in the Chugach Mountains and central Prince William Sound causes focused, but less rapid, exhumation. Farther south in the Prince William Sound, plate boundary deformation transitions from strike-slip to nearly full convergence in the Montague Island and Hinchinbrook Island region, which is ˜20 km above the megathrust between the Yakutat microplate and overriding North American Plate. Montague and Hinchinbrook Islands are narrow, elongate, and steep, with a structural grain formed by several megathrust fault splays, some of which slipped during the 1964 M9.2 earthquake. Presented here are 32 new apatite (U-Th)/He (AHe) and 28 new apatite fission-track (AFT) ages from the Montague and Hinchinbrook Island regions. Most AHe ages are Hanning Bay and Patton Bay faults during the 1964 earthquake. AFT ages range from ˜5 Ma to ˜20 Ma and are also younger at the SW end of Montague Island. These ages and corresponding exhumation rates indicate that the Montague and Hinchinbrook Island region is a narrow zone of intense deformation probably related to duplex thrusting along one or more megathrust fault splays. I interpret the rates of rock uplift and exhumation to have increased in the last ˜5 My, especially at the southwest end of the island system and farthest from the region dominated by strike-slip and transpressional deformation to the northeast. The narrow band of deformation along these islands likely represents the northwestern edge of a broader swath of plate boundary deformation between the Montague-Hinchinbrook Island region and the Kayak Island

  17. Retroarc basin reorganization and aridification during Paleogene uplift of the southern central Andes (United States)

    Fosdick, J. C.; Reat, E. J.; Carrapa, B.; Ortiz, G.; Alvarado, P. M.


    Tectonic development of the Andean Cordillera has profoundly changed the topography, climate, and vegetation patterns of the southern central Andes. The Cenozoic Bermejo Basin in Argentina ( 30°S) provides a key record of thrust belt kinematics and paleoclimate south of the high-elevation Puna Plateau. Ongoing debate regarding the timing of initiation of upper plate shortening and Andean uplift persists, precluding a thorough understanding of the earlier tectonic and climatic controls on basin evolution. We present new sedimentology, detrital geochronology, sandstone petrography, and subsidence analysis from the Bermejo Basin that reveal siliciclastic-evaporative fluvial and lacustrine environments prior to the main documented phase of Oligocene-Miocene shortening of the Frontal Cordillera and Argentine Precordillera. We report the first radiometric dates from detrital zircons collected in the Ciénaga del Río Huaco Formation, previously mapped as Permian, that constrain a Late Cretaceous ( 95-93 Ma) maximum depositional age. Provenance and paleocurrent data from these strata indicate that detritus was derived from dissected arc and cratonic sources in the north and northeast. Detrital zircon U-Pb ages of 37 Ma from the overlying red beds suggest that foredeep sedimentation began by at least the late Eocene. At this time, sediment dispersal shifted from axial southward to transversal eastward from the Andean Arc and Frontal Cordillera. Subsidence analysis of the basin fill is compatible with increasing tectonic deformation beginning in Eocene time, suggesting that a distal foredeep maintained fluvial connectivity to the hinterland during topographic uplift and unroofing of the Frontal Cordillera, prior to Oligocene-Miocene deformation across the Precordillera.

  18. Evidence for long-term uplift on the Canary Islands from emergent Mio Pliocene littoral deposits (United States)

    Meco, Joaquín; Scaillet, Stéphane; Guillou, Hervé; Lomoschitz, Alejandro; Carlos Carracedo, Juan; Ballester, Javier; Betancort, Juan-Francisco; Cilleros, Antonio


    Several islands in the Canarian archipelago show marine deposits with identical fossil faunas, which are generally assigned to different glacioeustatic marine episodes: mainly Pleistocene episodes in Lanzarote and Fuerteventura, and Mio-Pliocene ones in Gran Canaria. Three fossil species ( Saccostrea chili, Nerita emiliana and Strombus coronatus) characterize all the marine deposits from southern Lanzarote, to the west and south of Fuerteventura and northeast of Gran Canaria. Three other species ( Ancilla glandiformis, Rothpletzia rudista and Siderastraea miocenica) confirm the chronostratigraphic attribution of these deposits. Other more occasional fossils (as Chlamys latissima, Isognomon soldanii and Clypeaster aegyptiacus) fit an upper Miocene and lower Pliocene age. This agrees with new K/Ar ages obtained from pillow lavas emplaced into the marine deposits (ca. 4.1 Ma in Gran Canaria, ca. 4.8 Ma in Fuerteventura) and from underlying (ca. 9.3 Ma in Gran Canaria) or overlying (ca. 9.8 Ma in Lanzarote) lava flows. The marine deposits are eroded but large continuous segments are preserved sloping gently towards the coast. Variations in the highest and the lowest elevations of the deposits apsl (above present sea level) indicate post-depositional uplift movements. Glacioeustatic causes are unlikely to be responsible for these variations on the basis of the coastal location of the deposits and their equatorial fauna characteristic of Mio-Pliocene corals. Differential uplift of the deposits across the archipelago is argued to result from the progressive seaward tilting of the islands along the insular volcanic trail marking the westward migration of hot spot head since 20 Ma. Successive westward accretion of younger volcanic edifices resulted in increasing lithostatic load of the crust with progressive (diachronous) tilting of the older edifices and their palaeo-shorelines marked by past coastal deposits.

  19. Mountain uplift explains differences in Palaeogene patterns of mammalian evolution and extinction between North America and Europe. (United States)

    Eronen, Jussi T; Janis, Christine M; Chamberlain, C Page; Mulch, Andreas


    Patterns of late Palaeogene mammalian evolution appear to be very different between Eurasia and North America. Around the Eocene-Oligocene (EO) transition global temperatures in the Northern Hemisphere plummet: following this, European mammal faunas undergo a profound extinction event (the Grande Coupure), while in North America they appear to pass through this temperature event unscathed. Here, we investigate the role of surface uplift to environmental change and mammalian evolution through the Palaeogene (66-23 Ma). Palaeogene regional surface uplift in North America caused large-scale reorganization of precipitation patterns, particularly in the continental interior, in accord with our combined stable isotope and ecometric data. Changes in mammalian faunas reflect that these were dry and high-elevation palaeoenvironments. The scenario of Middle to Late Eocene (50-37 Ma) surface uplift, together with decreasing precipitation in higher-altitude regions of western North America, explains the enigma of the apparent lack of the large-scale mammal faunal change around the EO transition that characterized western Europe. We suggest that North American mammalian faunas were already pre-adapted to cooler and drier conditions preceding the EO boundary, resulting from the effects of a protracted history of surface uplift. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  20. Anomalous transient uplift observed at the Lop Nor, China nuclear test site using satellite radar interferometry time-series analysis

    National Research Council Canada - National Science Library

    P. Vincent; S. M. Buckley; D. Yang; S. F. Carle


    ... is observed at the Lop Nor, China nuclear test site using ERS satellite SAR data. Using an InSAR time-series analysis method, we show that an increase in absolute uplift with time is observed between 1997 and 1999...

  1. A qualitative analysis of stress, uplifts and coping in the personal and professional lives of Singaporean nurses. (United States)

    Lim, Joanne; Hepworth, Julie; Bogossian, Fiona


    This paper is a report of a descriptive study of nurses' experiences of daily stress and coping. Much of the research on stress in nursing is quantitative and has focused on only work stressors. Moreover, few studies have examined the uplifting side of living and the role it may play in moderating stress. A theoretical framework on stress and coping, 'hassles' and 'uplifts' was used to examine nurses' experiences across their personal and professional lives from a qualitative perspective. A purposive sample of Singaporean hospital nurses (n = 23) identified using a snowball sampling technique, participated in two sets of email interviews in 2009. The qualitative data were analysed using thematic analysis. Three themes were identified as constituting daily hassles: (i) time pressures, (ii) nature of nursing work and (iii) multiple roles. Uplifts were expressed in relation to one main theme of feeling good extending across nurses' personal and professional lives. Three themes were identified as ways of coping: (i) taking time out, (ii) seeking emotional support and (iii) belief systems. The interaction between personal and professional life plays a major role in Singaporean nurses' experiences of stress and coping. However, stress may be ameliorated through effective management and strong familial support. Nurses and employers are recommended to use uplifts and identify ways of coping to minimize attrition and contribute to the development of a healthy workforce. © 2011 Blackwell Publishing Ltd.

  2. Uplift and volcanism of the SE Colombian Andes in relation to Neogene sedimentation in the Upper Magdalena Valley

    NARCIS (Netherlands)

    Wiel, van der A.M.


    The present study deals with the relation between Neogene uplift and volcanism of the SE Colombian Andes and sedimentation processes in the Upper Magdalena Valley. The southernmost part of the Upper Magdalena Valley, the S. Neiva Basin, is located between latitudes 2°08'-2°31 N and

  3. Tibetan uplift prior to the Eocene-Oligocene climate transition: Evidence from pollen analysis of the Xining Basin

    NARCIS (Netherlands)

    Dupont-Nivet, G.; Hoorn, C.; Konert, M.


    Uplift of the Tibetan Plateau and the Himalayas since the onset of the Indo-Asia collision is held responsible for Asian aridification and monsoon intensification, but may also have gradually cooled global climate, leading to the 34 Ma Eocene-Oligocene transition. To unravel the interplay between

  4. some morphological effects related to a non-uniform uplifting of crustal blocks in Northern Sicily (Central Mediterranean) (United States)

    Nigro, Fabrizio; Renda, Pietro; Favara, Rocco


    We can distinguish two morphological evolutions of the drainage basins which develop in the earth's sectors subjected to uplift and tilting, in relationship to their antecedence or subsequence in comparison to the tectonic process. If this process begins in concomitance with a geomorphic cycle the main valleys of the drainage basins will longitudinally be developed according to the tilting direction which the crustal block is subjected. But if the non-uniform vertical movement develops in a sector already characterized by the presence of a idrographic network, this can be influenced in its pattern in various ways. A crustal block contemporarily subject to uplift and tilting will be characterized to its inside, at the end of this process, by more elevated and less elevated sectors. The erosive ground processes suffer this non-uniform vertical movement and since it gradually develops in time, landforms, as valleys of drainage basins, will suffer analogous variations. If pre-existing, the slopes of the valleys will be subjected to tilting also and one of the characteristics in the evolution of the reliefs connected with the uplift and the tilting of crustal blocks are represented by the progressive asymmetry of the slopes of a valley. The uplift and the tilting of the block progressively determines a difference of inclination of the slopes of the incising valley. This effect is given by the progressive incision and migration of the axis of the valley that it determines slopes with crests to different middle elevation between the right side and that left. The erosional process that determines him with the uplift and the tilting of the crustal blocks are characterized by a greater erosion rate in the sectors of head of the slope that is mostly raised. Likewise, the migration of the river consistent with the tilting direction determines a greater rate of erosion along one of the banks. The general morphometric result can be that of the individualization of slopes that

  5. Characteristics and age of an uplift signal in the Biga Peninsula (NW Turkey) from a mix of geomorphic indices (United States)

    Demoulin, Alain; Bayer Altin, Turkan; Beckers, Arnaud


    Situated in the area where the western end of the North Anatolian Fault Zone meets the extensional domain of the North Aegean Sea, the Kazdag Mountain range (Biga Peninsula, NW Turkey) is known to have undergone Plio-Quaternary uplift. However, no detailed chronology of this presumably ongoing uplift phase was so far available. In order to obtain a first-order estimate of the time of the last tectonic perturbation (uplift rate change) in the region, we performed a morphometric study of the fluvial landscape at the scale of the Biga Peninsula, coupling the recently developed R/SR analysis of the drainage network with concavity and steepness measures of a set of 29 rivers of all sizes. Defined as the ratio of two-by-two differences between hypsometric integrals describing respectively a catchment's topography, its drainage network "composite profile" and the trunk stream profile, the R metric is a measure of the catchment's incision response to a relative base level lowering. The SR index is then simply the slope of the regional relation R = f(ln A), a feature characteristic of the time elapsed since uplift caused an erosion wave to propagate in the drainage system. We obtained a SR value of 0.324±0.035 that, according to the t = f(SR) relation established by Demoulin (2012), yields an age range of 0.54-1.29 Ma and a most probable value of 0.82 Ma for the time of the last uplift signal in the Biga Peninsula. We also carried out an analysis of knickpoint migration in a subset of rivers, modelling their propagation by the stream power law under different assumed ages so as to compare the obtained values of the K coefficient with values mentioned in the literature. The positive results of this analysis, yielding realistic K values for ages around 0.8 Ma, lend independent support to our morphometric estimate of the uplift time, moreover corroborated by published observations suggesting basin inversion of the Bayramiç and Çanakkale depressions at the same epoch. We

  6. Modulation of the erosion rate of an uplifting landscape by long-term climate change: An experimental investigation (United States)

    Moussirou, Bérangé; Bonnet, Stéphane


    Whether or not climatic variations play a major role in setting the erosion rate of continental landscapes is a key factor in demonstrating the influence of climate on the tectonic evolution of mountain belts and understanding how clastic deposits preserved in sedimentary basins may record climatic variations. Here, we investigate how a change in precipitation influences the erosional dynamics of laboratory-scale landscapes that evolved under a combination of uplift and rainfall forcings. We consider here the impact of a decrease in the precipitation rate of finite duration on the erosive response of a landscape forced by a constant uplift and initially at a steady state (SS1). We performed several experiments with the same amplitude but different durations of precipitation decrease (Tp). We observe that the decrease in precipitation induces a phase of surface uplift of landscapes to a new steady state condition (SS2); however, the details of the uplift histories (timing, rate) differ between the experiments according to Tp. We also observe a decrease in the erosion rate induced by the precipitation change; however, the timing and amplitude of this decrease vary according to Tp, defining a delayed and damped erosion signal. Our data show that the landscape response to precipitation change is dictated by a critical water-to-rock ratio (ratio of precipitation over uplift) that likely corresponds to a geomorphic threshold. Our study suggests that variations in precipitation that occur at a geological time scale (> 106 years) may have a weak impact on the erosion of landscapes and on the delivery of siliciclastic material to large rivers and sedimentary basins.

  7. Plateau Uplift, Erosion, and Geodynamic Forcing in Southern Africa from Integration of Landscape Evolution Modeling with Geologic and Thermochronologic Constraints (United States)

    Stanley, J. R.; Braun, J.; Flowers, R. M.


    The southern African plateau is a dominant feature of African topography but there is considerable debate about when and how it formed. Cretaceous kimberlite activity and the presence of a large low shear seismic velocity province (LLSVP) in the deep mantle below southern Africa have lead many to propose uplift related to mantle processes. Better constraints on the timing of uplift have the potential to constrain the nature of the LLSVP and the source of support for southern Africa's anomalous elevations. However, surface uplift is difficult to detect directly in the geologic record and the relationships between mantle sourced uplift and erosion are not necessarily direct. Here, we use a landscape evolution model combined with data constraining the spatiotemporal erosion patterns across southern Africa to explore how topographic development and erosion are related. We integrate a highly efficient landscape evolution model (FastScape, Braun and Willett, 2013) and a thermal module with a large apatite (U-Th)/He (AHe) thermochronologic dataset, sedimentary flux volumes for the major offshore basins, and geologic observations to address these questions. We used inversion methods based on the Neighborhood Algorithm to investigate how data is best simulated by the model while varying model parameters related to plateau uplift and the physical characteristics of the eroding material. Results from the inversions show that the data are sufficient to constrain many model parameters. Additionally, we show that the combination of different types of data, and in particular the spatiotemporal erosion information from the AHe thermochronologic results, is valuable for constraining many of these parameters. We show that the geometry and physical characteristics of the overlying sedimentary basin, as well as the characteristics of the geodynamic forcing, have significant control on plateau erosion patterns. It is therefore important to consider both geodynamics and surface controls

  8. Fluid-driven uplift at Long Valley Caldera, California: Geologic perspectives (United States)

    Hildreth, Wes


    Since persistent seismicity began in the Sierra Nevada adjacent to Long Valley caldera in 1978-1980, intracaldera unrest has been marked by (1) episodes of uplift totaling 83 cm, centered on the middle Pleistocene resurgent dome, and (2) recurrent earthquake swarms along a 12-km-long segment of the caldera's ring-fault zone that is contiguous with both the dome and the Sierran seismogenic domain. Others have attributed the recent unrest to magmatic intrusion(s), but it is argued here that evidence for new magma is lacking and that ongoing uplift and ring-fault-zone seismicity are both promoted by ascent of aqueous fluid released by second boiling of the residue of the enormous Pleistocene rhyolitic reservoir terminally crystallizing at depths ≥ 10 km. For 2 Myr, eruptive vent clusters migrated southwestward from Glass Mountain to Mammoth Mountain. There has been no eruption on the resurgent dome since 500 ka, and since 230 ka volcanism has been restricted to the caldera's west moat and contiguous Sierran terrain, both outside the structural caldera. High-temperature hydrothermal activity in the central caldera waned after 300 ka, cooling the Pleistocene rhyolitic focus to the extent that drilling on the resurgent dome found mid-caldera temperature to be only 100 °C and isothermal at depths of 2-3 km. Beneath most of the resurgent dome, there is little seismicity at any depth, no emission of magmatic CO2 or other magmatic gases, no elevated 3He/4He ratios, and only normal to below-normal heat flow. Most of the 75-km-long ring-fault zone is likewise aseismic, excepting only the 12-km segment contiguous with the extracaldera seismogenic domain in the Sierra. Since 1980, the Sierran seismicity has released 3.6 times more cumulative seismic energy than have intracaldera earthquakes. The caldera seismicity is not driven by stresses associated with the adjacent uplift but, instead, by the extracaldera tectonic stressfield. Sierran seismicity activated the directly

  9. Hydromechanical Simulations of Surface Uplift due to CO2 Injection at In Salah (Invited) (United States)

    Morris, J. P.; Hao, Y.; Foxall, W.; McNab, W. W.


    We present recent simulations of the hydromechanical response of the reservoir and overburden associated with CO2 injection at In Salah. Using the best available field data for the reservoir and fault network properties, we are able to demonstrate excellent agreement between simulation and observation. These results are providing new insight into the fate of the CO2 about one of the injectors where intriguing morphology was observed in surface uplift. Additionally, this work is helping to better establish the advantages and limitations of interpreting surface displacements to guide our understanding of fluid fate. The In Salah Project (a joint venture of BP, StatoilHydro and Sonatrach) includes a CO2 sequestration effort that has successfully injected millions of tons of CO2 into a deep saline formation close to a producing gas field in Algeria. We have been funded by the Joint Industry Project (A consortium consisting of BP, StatoilHydro and Sonatrach, hereafter the JIP) and the U.S. Department of Energy to investigate the role of injection induced mechanical deformation and geochemical alteration at the In Salah CO2 storage project. Here we focus upon the hydromechanical portion of the study. We have performed detailed simulations of the hydromechanical response in the vicinity of the KB-502 CO2 injector specifically because the morphology of the observed surface deformation differed from that above the other injectors at the field. First we performed a geomechanical analysis to predict which faults are flow conduits and which are flow barriers. NUFT simulations were performed based upon this information using permeability fields for the reservoir provided by the JIP. These results indicate that the presence of faults in the vicinity of the KB-502 injector may be responsible for the early breakthrough of CO2 observed at a nearby well, KB-5. We have simulated the mm-scale uplift of the overburden and compared the results with observed deformation using InSAR data

  10. Mantle uplift and exhumation caused by long-lived transpression at a major transform fault (United States)

    Maia, Marcia; Sichel, Susanna; Briais, Anne; Brunelli, Daniele; Ligi, Marco; Campos, Thomas; Mougel, Bérengère; Hémond, Christophe


    Large portions of slow-spreading ridges have mantle-derived peridotites emplaced either on, or at shallow levels below the sea floor. Mantle and deep rock exposure in such contexts results from extension through low-angle detachment faults at oceanic core complexes or, along transform faults, to transtension due to small changes in spreading geometry. In the Equatorial Atlantic, a large body of ultramafic rocks at the large-offset St. Paul transform fault forms the archipelago of St. Peter & St. Paul. These islets are emplaced near the axis of the Mid-Atlantic Ridge (MAR), and have intrigued geologists since Darwin's time. They are made of variably serpentinized and mylonitized peridotites, and are presently being uplifted at a rate of 1.5 mm/yr, which suggests tectonic stresses. The existence of an abnormally cold upper mantle or cold lithosphere in the Equatorial Atlantic was, until now, the preferred explanation for the origin of these ultramafics. High-resolution geophysical data and rock samples acquired in 2013 show that the origin of the St. Peter & St. Paul archipelago is linked to compressive stresses along the transform fault. The islets represent the summit of a large push-up ridge formed by deformed mantle rocks, located in the center of a positive flower structure, where large portions of mylonitized mantle are uplifted. The transpressive stress field can be explained by the propagation of the northern MAR segment into the transform domain. The latter induced the overlap of ridge segments, resulting in the migration and segmentation of the transform fault and the creation of a series of restraining step-overs. A counterclockwise change in plate motion at 11 Ma initially generated extensive stresses in the transform domain, forming a flexural transverse ridge. Shortly after the plate reorganization, the MAR segment located on the northern side of the transform fault started to propagate southwards, adjusting to the new spreading direction. Enhanced melt

  11. Crustal uplift of the Precambrian cratons due to metamorphism in crustal rocks under infiltration of mantle fluids (United States)

    Artyushkov, Eugene; Chekhovich, Peter; Korikovsky, Sergey; Massonne, Hans-Joachim


    Precambrian cratons cover about 70% of the total area of the continents. During the last several million years cratonic areas underwent rapid uplift, from 100-200 m in East Europe to 1000-1500 m Southern Africa. Shortening of the Precambrian crust terminated half a billion years ago or earlier and this popular mechanism cannot be applied to its recent uplift. Large thickness of cratonic mantle lithosphere, 100-200 km in most regions, together with its low density precludes delamination of this layer and magmatic underplating as possible causes of recent uplift. It cannot be precluded that in some cratonic regions recent uplift occurred due to delamination of the lower part of mantle lithosphere with the density increased by metasomatism. Even a small uplift of ≥ 100-200 m would require delamination of a thick layer of mantle lithosphere. As a result a temperature drop of > 200 C would arise at the base of the lithosphere producing a shear wave velocities drop of > 2%. According to the seismic tomography data such a drop in VS is observed only in some regions with the Precambrian lithosphere, e.g., in Northeastern Africa. Spatial distribution of the Precambrian cratons is quite different from that predicted by the main models of dynamic topography in the mantle. Moreover, many uplifted blocks are bounded by steep slopes hundreds of meters to one kilometer high and only tens of kilometers wide. Such slopes could not have been formed by bending of thick cratonic lithosphere under the forces acting from below. Their recent formation indicates rock expansion within the crust at shallow depth comparable with the slope width. Rocks formed at the pressure P ˜ 0.5-1.0 GPa are widespread on the Precambrian cratons. This indicates that during their lifetime a layer of rocks ˜ 15-30 km thick has been removed from the crustal surface by denudation. As a result rocks which were initially located in the lower crust emerged to the middle or upper crust. Due to metamorphic

  12. Assessment of Differential Uplift Along South Java, Indonesia from Terrace Elevations Mapped with Structure from Motion Photogrammetry (United States)

    Andreini, J.; Bunds, M. P.; Harris, R. A.; Yulianto, E.; Horns, D. M.; Prasetyadi, C.; Putra, P. S.


    Assessment of Differential Uplift Along South Java, Indonesia from Terrace Elevations Mapped with Structure from Motion Photogrammetry Jeremy Andreini, Michael Bunds, Ronald Harris, Eko Yulianto, Carolus Prasetyadi, Daniel Horns, Purna Putra Is differential uplift occurring on the south coast of Java? Java is on the southern edge of the Sunda plate, above the subducting Indo-Australian plate. Its south coast is 300 km north of the Java Trench and south of the volcanic arc that runs the length of Java. We are investigating relations between marine terraces and convergence, normal faulting associated with tectonically induced basin subsidence, eustatic sea level change, and variations in sediment supply from volcanic activity. Exposed bedrock along the coast includes upper Miocene basinal limestone, and localized exposure of underlying Miocene reef deposits and Oligo-miocene volcanic basement. Differential uplift in the past is implied by north-south trending horst-like ridges of Miocene reef sediment and volcanic basement that have been exhumed from greater depth than adjacent upper Miocene strata. We utilized Quaternary terrace elevations at four locations (Pangamalang, Pangandaran, Karanghawu, and Pacitan). Elevations were measured using traverses with handheld GPS units, profiles made with RTK GPS, and digital surface models (DSMs).The DSMs have 5 cm pixels and were constructed using structure-from-motion (SfM) software to process photos collected with quadcopters equipped with a 24 Mpixel Sony A5100 camera; their vertical RMS error relative to checkpoints measured on bare ground is 6 cm. SfM processing was done in the field with a specially built portable workstation. Four sets of terraces (T) with the following elevations were identified: T1 0-.5 m, T2 2 m, T3 17 m, T4 22 m. We interpret T1 to be the modern wave-cut platform, T2 to represent Holocene uplift of a Holocene terrace or possibly modern deposition, T3 to result from Marine Isotope Stage 5e. T4 occurs

  13. Uplift of the South African Plateau: mantle-scale deformation, long wavelength relief growth and offshore sediment budget (United States)

    Guillocheau, François; Dauteuil, Olivier; Baby, Guillaume; Robin, Cécile


    The South African Plateau is one of the largest very long wavelength relief (x1000 km) of the world that could be related to mantle dynamics and the effect of the African superplume. Unfortunately, the timing of the uplift and the different steps of the relief growth are still debated with a Late Cretaceous uplift scenario and an Oligocene one. Whatever model, few attentions were paid to the evolution of the overall geomorphic system, from the upstream erosional system to the downstream depositional system. This study is based, onshore, on the mapping and chronology of all the macroforms (weathering surfaces and associated alterites, pediments and pediplains, incised rivers, wave-cut platforms) dated by intersection with the few preserved sediments and the volcanics (mainly kimberlites pipes) and, offshore, on a more classical dataset of seismic lines and petroleum wells (characterization and dating of forced regression, sediment volume measurement, etc..). The main result of this study is that the South African Plateau is an old Late Cretaceous Plateau reactivated during Paleogene times and fossilized since the Middle Miocene. • During Late Cretaceous, in a semiarid climatic setting, the main uplift occurred from the east (around 95 Ma) to the west (around 75 Ma) and could result from the migration of the African plate over the African superplume: This is the paroxysm of the erosion with the growth of a large delta offshore present-day Orange River mouth (sedimentation rate around 100 000 km3/Ma). • During Paleocene - Mid Eocene times, in more humid conditions and in response to a more subtle long wavelength deformation, pedimentation occurred mainly localised along Cape Fold Belt feeding a large delta offshore western Cape Peninsula. During Mid Eocene times, all those landscapes are fossilized and weathered by laterites. • Late Eocene and Oligocene is the second period of uplift of the Plateau, localised along its Indian Ocean side (Drackensberg Moutains

  14. A land uplift model in Fennoscandia combining GRACE and absolute gravimetry data (United States)

    Müller, Jürgen; Naeimi, Majid; Gitlein, Olga; Timmen, Ludger; Denker, Heiner

    Since 2002 the GRACE satellite mission provides monthly solutions of the Earth’s gravity field reflecting mass variations on various spatial and temporal scales. The glacial isostatic adjustment (GIA)-induced trend signal in Fennoscandia can be obtained with a spatial resolution of about 300-400 km. Moreover, since 2003 the Institut für Erdmessung has carried out absolute gravity (AG) measurements in Fennoscandia in close cooperation with the Scandinavian partners. From the AG data, point-wise mass variations at the AG sites have been determined including the GIA-induced trend signal. For direct comparison of those point values with regional results from GRACE, vertical movements of the sites have been considered using rates determined from permanent GPS measurements. The various results for GIA-related effects agree well near the uplift center, although the different raw data contain different signal contributions. In a final step, we combine the AG trend values (including GPS rates) and the GRACE results to obtain a data-based solution of the present-day secular mass variation in Fennoscandia. Here, we present results of the individual techniques as well as the combined solution, where we also discuss possible errors sources.

  15. Integrated approaches to terminal Proterozoic stratigraphy: an example from the Olenek Uplift, northeastern Siberia (United States)

    Knoll, A. H.; Grotzinger, J. P.; Kaufman, A. J.; Kolosov, P.


    In the Olenek Uplift of northeastern Siberia, the Khorbusuonka Group and overlying Kessyusa and Erkeket formations preserve a significant record of terminal Proterozoic and basal Cambrian Earth history. A composite section more than 350 m thick is reconstructed from numerous exposures along the Khorbusuonka River. The Khorbusuonka Group comprises three principal sedimentary sequences: peritidal dolomites of the Mastakh Formation, which are bounded above and below by red beds; the Khatyspyt and most of the overlying Turkut formations, which shallow upward from relatively deep-water carbonaceous micrites to cross-bedded dolomitic grainstones and stromatolites; and a thin upper Turkut sequence bounded by karst surfaces. The overlying Kessyusa Formation is bounded above and below by erosional surfaces and contains additional parasequence boundaries internally. Ediacaran metazoans, simple trace fossils, and vendotaenids occur in the Khatyspyt Formation; small shelly fossils, more complex trace fossils, and acritarchs all appear near the base of the Kessyusa Formation and diversify upward. The carbon-isotopic composition of carbonates varies stratigraphically in a pattern comparable to that determined for other terminal Proterozoic and basal Cambrian successions. In concert, litho-, bio-, and chemostratigraphic data indicate the importance of the Khorbusuonka Group in the global correlation of terminal Proterozoic sedimentary rocks. Stratigraphic data and a recently determined radiometric date on basal Kessyusa volcanic breccias further underscore the significance of the Olenek region in investigations of the Proterozoic-cambrian boundary.

  16. Constructing de Sitter vacua in no-scale string models without uplifting

    Energy Technology Data Exchange (ETDEWEB)

    Covi, Laura [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Gomez-Reino, Marta [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Gross, Christian [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Palma, Gonzalo A. [Leiden Univ. (Netherlands). Lorentz Inst. for Theoretical Physics; Scrucca, Claudio A. [Ecole Polytechnique Federale de Lausanne (Switzerland). Inst. de Theorie des Phenomenes Physiques


    We develop a method for constructing metastable de Sitter vacua in N=1 supergravity models describing the no-scale volume moduli sector of Calabi-Yau string compactifications. We consider both heterotic and orientifold models. Our main guideline is the necessary condition for the existence of metastable vacua coming from the Goldstino multiplet, which constrains the allowed scalar geometries and supersymmetry-breaking directions. In the simplest non-trivial case where the volume is controlled by two moduli, this condition simplifies and turns out to be fully characterised by the intersection numbers of the Calabi-Yau manifold. We analyse this case in detail and show that once the metastability condition is satisfied it is possible to reconstruct in a systematic way the local form of the superpotential that is needed to stabilise all the fields. We apply then this procedure to construct some examples of models where the superpotential takes a realistic form allowed by flux backgrounds and gaugino condensation effects, for which a viable vacuum arises without the need of invoking corrections to the Kaehler potential breaking the noscale property or uplifting terms. We finally discuss the prospects of constructing potentially realistic models along these lines. (orig.)

  17. Orogen-scale uplift in the central Italian Apennines drives episodic behaviour of earthquake faults. (United States)

    Cowie, P A; Phillips, R J; Roberts, G P; McCaffrey, K; Zijerveld, L J J; Gregory, L C; Faure Walker, J; Wedmore, L N J; Dunai, T J; Binnie, S A; Freeman, S P H T; Wilcken, K; Shanks, R P; Huismans, R S; Papanikolaou, I; Michetti, A M; Wilkinson, M


    Many areas of the Earth's crust deform by distributed extensional faulting and complex fault interactions are often observed. Geodetic data generally indicate a simpler picture of continuum deformation over decades but relating this behaviour to earthquake occurrence over centuries, given numerous potentially active faults, remains a global problem in hazard assessment. We address this challenge for an array of seismogenic faults in the central Italian Apennines, where crustal extension and devastating earthquakes occur in response to regional surface uplift. We constrain fault slip-rates since ~18 ka using variations in cosmogenic 36Cl measured on bedrock scarps, mapped using LiDAR and ground penetrating radar, and compare these rates to those inferred from geodesy. The 36Cl data reveal that individual faults typically accumulate meters of displacement relatively rapidly over several thousand years, separated by similar length time intervals when slip-rates are much lower, and activity shifts between faults across strike. Our rates agree with continuum deformation rates when averaged over long spatial or temporal scales (104 yr; 102 km) but over shorter timescales most of the deformation may be accommodated by <30% of the across-strike fault array. We attribute the shifts in activity to temporal variations in the mechanical work of faulting.

  18. The Silurian play in the Tazhong Uplift, Tarim Basin, northwestern China

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Xiu Xiang; Fan, Qiuhai [China Petroleum University (Beijing), Changping (China). Basin and Oil Reservoir Research Center; China Petroleum University (Beijing), Changping (China). Oil and Gas Migration and Accumulation Mechanism Laboratory; Zhao, Fengyun; Wang, Qinghua; Yang, Haijur [Tarim Oil Field Company, PetroChina, Korle, Xinjiang (China); Xie, Qilai [Guangzhou Geochemical Research Institute, Chinese Academy of Sciences, Guangzhou, Guangdong (China)


    Silurian sandstone reservoirs in the Tazhong Uplift in the Tarim Basin, northwestern China are rich in bitumen and movable oil. Analysis of the biological markers indicates that the bitumen and movable oil came from two source rocks in the Cambrian and Middle/Upper Ordovician system, both of which are belong to marine facies. The Silurian system experienced three stages of oil filling, namely Late Caledonian period (400 Ma), Late Hercynian period (240 Ma) and Yanshan-Himalayan (40 Ma) period. Most of the oil emplaced in the Late Caledonian was subsequently oxidized to bitumen. The movable oil found at the present time was mainly generated from the Middle/Upper Ordovician source rocks, with only a minor contribution from the Cambrian source rocks generating in the two later periods. Bitumen and heavy crude were largely trapped below a red mudstone unit while movable oil was concentrated below an underlying gray mudstone unit (the middle sub-section of bitumen sandstone section). Lateral migration into the Silurian reservoirs took place from northwest to southeast in each stage and was controlled by an inherited palaeohigh. While individual relatively limited in extent, the tidal-flat sandstones of the main reservoir have stacking patterns that generate extensive sand sheets. Faulting can both enhance connectivity and create traps. (author)

  19. Impacts of Tibetan Plateau uplift on atmospheric dynamics and associated precipitation δ18O (United States)

    Botsyun, Svetlana; Sepulchre, Pierre; Risi, Camille; Donnadieu, Yannick


    Palaeoelevation reconstructions of mountain belts have become a focus of modern science since surface elevation provides crucial information for understanding both geodynamic mechanisms of Earth's interior and the influence of mountain growth on climate. Stable oxygen isotopes palaeoaltimetry is one of the most popular techniques nowadays, and relies on the difference between δ18O of palaeo-precipitation reconstructed using the natural archives, and modern measured values for the point of interest. Our goal is to understand where and how complex climatic changes linked with the growth of mountains affect δ18O in precipitation. For this purpose, we develop a theoretical expression for the precipitation composition based on the Rayleigh distillation and the isotope-equipped atmospheric general circulation model LMDZ-iso outputs. Experiments with reduced height over the Tibetan Plateau and the Himalayas have been designed. Our results show that the isotopic composition of precipitation is very sensitive to climate changes related to the growth of the Himalayas and Tibetan Plateau. Specifically our simulations suggest that only 40 % of sampled sites for palaeoaltimetry depict a full topographic signal, and that uplift-related changes in relative humidity (northern region) and precipitation amount (southern region) could explain absolute deviations of up to 2.5 ‰ of the isotopic signal, thereby creating biases in palaeoelevation reconstructions.

  20. A resposta broncodilatadora em doentes com DPOC (dados do estudo UPLIFT

    Directory of Open Access Journals (Sweden)

    D. Tashkin


    Full Text Available Resumo: No início do estudo, foi realizada espirometria antes e depois de 80 μg de ipratrópio e 400 μg de salbutamol, administrados 90 e 30 minutos antes, respectivamente. A administração de dois broncodilatadores e a sua temporalidade teve como objectivo atingir a broncodilatação máxima ou quase máxima. O FEV1 basal após esta broncodilatação, no estudo UPLIFT, permitiu: – examinar a resposta broncodilatadora aguda numa grande coorte de doentes com DPOC moderada a muito grave; – determinar o que pode ser considerado critério de resposta usando vários critérios de reversibilidade; – avaliar as características dos doentes com e sem reversibilidade.

  1. Active Tectonic Uplift of the Danba Area in the Eastern Tibetan Plateau, China (United States)

    Ho, Hou-Ping; Chang, Chung-Pai; Horng, Chorng-Shern; Hsu, Yi-Chun


    Danba, an area with extreme exhumation, locates between Longmenshan orogen and Xianshuihe sinistral fault zone in the eastern Tibetan Plateau. The Tibetan plateau was built by the convergence between Indo-Australian plate and Eurasian plate since early Cenozoic. However, the eastward lower crustal flow under the plateau obstructed by the Yangtze craton soon after this convergence and generated a very complex structural phenomenon. We make use of two methods, stress analysis and magnetic measurement, to understand the processes and mechanisms of this structural complexity. First, to be aware of the principle compressive stress in this area, we measure slickensides in the field from Danba area to the middle segment of Xianshuihe fault zone to carry out a series of analysis. We then obtain the stress field of this area. In addition, due to comprehend the magnetic characteristics of low-grade metamorphic rocks and volcanic rocks in this area, we process the rock magnetic measurement of hysteresis loop and X-ray diffraction analysis. The occurrence of pyrrhotite can be taken as an important isograd in low-grade metamorphic rocks, which is helpful for stratigraphic and structural studies. Based on our preliminary results, we propose a structural evolution model to explain the rapid uplift of this area.

  2. Dynamic uplift and erosion history of the Colorado Plateau: New insights from a SW-NE thermochronologic transect (United States)

    Robert, X.; Reiners, P.; Whipple, K. X.; Moucha, R.; Forte, A.


    The Colorado Plateau (CP), Paleozoic and Mesozoic sediments overlapped by Jurassic to Upper Cretaceous marine sediments is uplifted nowadays at ~1.9 km mean elevation with extremely limited crustal shortening. Deep buoyancy-driven dynamics are sometimes proposed to explain part of this uplift, but the lack of critical data and the inherently non-observable convective mantle contribute to a lack of consensus on the forces that are responsible for such features. Given recent advances in the dynamic interpretations of tomographic density variations in the mantle, [Moucha et al., 2009] simulate realistic 3D mantle convection in response to the observed mantle heterogeneity, and predict back- and forward in time the evolution of mantle flow, and thus mantle-driven dynamic surface uplift and/or subsidence. This 30 Ma retrodictions of mantle convection model carries intriguing implications for the post-Laramide evolution of the Grand Canyon (GC), the Colorado River (CR) and Lake Bidahochi that may help reconcile numerous geologic, geomorphic, and low-temperature thermochronologic data. Our analysis of the CR profile inferred from the dynamic uplift retrodictions suggests 3 major events in the post-Laramide evolution of the CP. (1) 30 to 15 Ma: Regular and homogeneous uplift (300 to 400 m) throughout the whole plateau with potential incision of the western GC with Grand Wash Cliffs tectonic relief development ~18 Ma. (2) ~15 to ~8 Ma: further uplift concentrated in the SW CP, tilting the plateau back to the E and possibly ponding the upper CR, plausibly explaining the formation of Lake Bidahochi (~190 m of observed lake sediments) and sustaining the incision of western GC. (3) ~8 to 0 Ma: NE migration of the wave of uplift, tilting the southwestern CP back to the W. It coincides with (and may have triggered) hypothesized Lake Bidahochi spillover that may have caused the dramatic post-6Ma incision of the GC. We also obtained single-grains apatite (U

  3. Biostratigraphic evidence of dramatic Holocene uplift of Robinson Crusoe Island, Juan Fernández Ridge, SE Pacific Ocean (United States)

    Sepúlveda, P.; Le Roux, J. P.; Lara, L. E.; Orozco, G.; Astudillo, V.


    A study of the biostratigraphy and sedimentology of Holocene deposits on Robinson Crusoe Island (RCI) on the Juan Fernández Ridge (JFR) indicates that a~dramatic but localized uplift occurred since 8000 BP, at a rate of about 8.5 mm yr-1. In fact, supratidal flats and sand layers with marine gastropods (mostly Nerita sp.) are now exposed ca. 70 m a.s.l., and covered by transitional dunes. The last volcanic activity on RCI occurred at ca. 0.8 Ma (active hotspot located 280 km further west) and there is no sign of a compensating bulge that explains this uplift, isobaths of the sea floor instead suggesting general subsidence. However, modeling indicates that large-scale landslides followed by isostatic rebound are a viable explanation, partially reflected in the low-resolution bathymetry of the area.

  4. Long-Term Uplift in the Altiplano-Puna Neovolcanic Zone: Evidence of an Active Magmatic Diapir? (United States)

    Fialko, Y.; Pearse, J.


    We present InSAR observations of a long-term uplift in the Altiplano-Puna neovolcanic zone (central Andes, South America). Previous observations revealed a a massive Ultra Low Velocity Zone (ULVZ) at depth of 17-19 km (Zandt et al., 2003), and surface deformation that was attributed to Uturuncu, a dormant volcano in the middle of the Altiplano-Puna neovolcanic zone (Pritchard and Simons, 2002). Our time series analysis of combined data from different sensors (ERS-1/2 and ENVISAT), satellite tracks, and observation modes (fine beam and ScanSAR) reveals that the central uplift has persisted at a nearly constant rate of ~1 cm/yr over the last two decades, and is surrounded by a broad zone of subsidence. We use the satellite line-of-sight velocities from different look directions to constrain the depth and geometry of the inferred sources of magmatic unrest. Inversions based on elastic half-space models indicate that the inflation source is located well below the brittle-ductile transition, and likely resides at the depth of the seismically imaged ULVZ. We investigated the effects of inelastic deformation in the ambient crust using finite element models. The models incorporated laboratory-derived rheologies of the ambient crust, and geotherms appropriate for an active neo-volcanic zone such as the one in the Altiplano-Puna province. Based on a large number of numerical simulations constrained by the observed surface velocities, we conclude that the ongoing uplift and peripheral subsidence result from a large mid-crustal diapir fed by a partially molten source region in the middle crust. The observed pattern of surface deformation due to the Altiplano-Puna ULVZ is remarkably similar to that due to the Socorro Magma Body (SMB) in central New Mexico, USA (Pearse and Fialko, 2010), suggesting a common process. mosaic of the mean LOS velocity showing uplift and peripheral subsidence due to the inferred mid-crustal diapir.

  5. Controls on Erosion in the Western Tarim Basin: Implications for the Uplift of Northwest Tibet and Pamirs (United States)

    Clift, P. D.; Zheng, H.; Carter, A.; Böning, P.; Jonell, T. N.; Pahnke, K.


    While the processes controlling erosion on the southern monsoon-influenced side of the Tibetan Plateau have been explored, those that dominate the drier regions north of the plateau are less well understood. We use a multiproxy approach to quantify erosion and assess variability in three rivers, the Hotan River draining the North Kunlun Block, the Yarkand River originating from the Karakoram, and the Kashgar River that flows from the eastern Pamirs. U-Pb zircon dating of modern river sands points to a strong control by topography and precipitation mediated through glaciation on erosion intensity in the Yarkand. Apatite fission track ages are younger in the Hotan River than in the Kashgar. Both rivers yield younger ages and faster exhumation rates than in the Transhimalaya and the western edge of the Tibetan Plateau. Exhumation rates are estimated at 1000 m/m.y in the North Kunlun and 500 m/m.y. in the eastern Pamirs, which are exhuming more slowly than the western Pamirs in the recent past. Our data indicate the Yarkand drainage system is relatively young as no sediment similar to the modern Yarkand River is found in older Cenozoic foreland sedimentary rocks. Uplift of the North Kunlun is interpreted to have started by 17 Ma, somewhat after uplift of the Pamirs and Songpan Garze in NW Tibet, which started before 24 Ma. Sediment eroded from the Kunlun reached the foreland basin between 14 and 11 Ma. Uplift appears to be propagating north through time with North Kunlun exhumation accelerating before 3.7 Ma, likely linked to enhanced rock uplift at that time.

  6. Analyzing the effect of large rotations on the seismic response of structures subjected to foundation local uplift

    Directory of Open Access Journals (Sweden)

    El Abbas N.


    Full Text Available This work deals with seismic analysis of structures by taking into account soil-structure interaction where the structure is modeled by an equivalent flexible beam mounted on a rigid foundation that is supported by a Winkler like soil. The foundation is assumed to undergo local uplift and the rotations are considered to be large. The coupling of the system is represented by a series of springs and damping elements that are distributed over the entire width of the foundation. The non-linear equations of motion of the system were derived by taking into account the equilibrium of the coupled foundation-structure system where the structure was idealized as a single-degree-of-freedom. The seismic response of the structure was calculated under the occurrence of foundation uplift for both large and small rotations. The non-linear differential system of equations was integrated by using the Matlab command ode15s. The maximum response has been determined as function of the intensity of the earthquake, the slenderness of the structure and the damping ratio. It was found that considering local uplift with small rotations of foundation under seismic loading leads to unfavorable structural response in comparison with the case of large rotations.

  7. New approach to resolve the amount of Quaternary uplift and associated denudation of the mountain ranges in the Japanese Islands

    Directory of Open Access Journals (Sweden)

    Shigeru Sueoka


    Full Text Available Low-temperature thermochronology is a widely used tool for revealing denudation histories of mountain ranges. Although this technique has been applied mainly to continental orogens, such as the European Alps, Himalayas, and Andes, recent technological development of low-temperature thermochronology has made it applicable to a wider variety of mountain ranges with various sizes and tectonic histories. The Japanese Islands comprise young and active island arcs, where an early stage of mountain range formation is observed. Numerous attempts have been made to constrain the uplift and denudation histories of the mountains in the Japanese Islands using geologic, geomorphologic, or geodetic methods. However, the number of thermochronometric attempts has been limited primarily due to the small amount of total denudation since the initiation of the uplift. In this review paper, we introduce the tectonic and geomorphic settings of the mountain ranges in the Japanese Islands, and discuss previous attempts to estimate uplift or denudation of the Japanese mountains using methods other than thermochronology. Furthermore, we discuss problems of the thermochronometric applications in revealing denudation histories of the Japanese mountains. Finally, we present a case study of the Kiso Range in central Japan and discuss the current effectiveness and applicability of low-temperature thermochronology to the Japanese mountainous areas.

  8. Tectonic Uplift vs. Climatic Change Controlled Denudation: Evidence from Synthesized Basin and Thermochronology of the NE Tibetan Plateau (United States)

    Fang, X.; Song, C.; Yan, M.; Zhang, T.; Zhang, W.


    Denudation history and its driving forces are crucial to understand the roles of tectonics and climate, especially the role of the Tibetan Plateau in global weathering and climate change. However, it is very hard to distinguish each role of tectonics and climate. Here we reviewed and synthesized Cenozoic denudation and tectonic deformation and uplift histories of the NE Tibetan Plateau from detailed basin analyses and thermochronology. A simultaneous increase of sedimentation rate in all reviewed basins in the NE Tibetan Plateau is regarded as denudation event. Nine denudation events occurring at about 46-40Ma, 36-30Ma, 28-27Ma, 24-21Ma, 19-17Ma, 14-12Ma, 10-6Ma and 4-1Ma were found. These events, except those at 28-27Ma and 19-17Ma, are all synchronous in tectonic time scale with rapid cooling (denudation) events revealed by fission tract and U-Th/He dates of apatite grains in basin sediments and mountain rocks at different heights. We compare these denudation events with the tectonic uplift events summarized from occurrences of unconformity and growth strata and the rotation and shortening of basin and the global and regional climate records. It is found that the denudation events all match tectonic events, rather than climatic records. Therefore, we argue that tectonic uplift rather than climate places a major role in controlling mountain denudation.

  9. Magmatic constraints on rift development and the uplift of the Rwenzori Mountains in western Uganda (United States)

    Foley, Stephen; Link, Klemens; Tiberindwa, John; Barifaijo, Erasmus


    The northern end of the western branch of the East African rift valley in western Uganda is located at the junction between a Proterozoic belt to the south and continuous Archaean crust of the Congo-Tanzania craton to the north (1). The difficulty of rift propagation through the thick Archaean lithosphere may explain the lack of a connection with the eastern rift branch around Lake Turkana. The >5,000m-high Rwenzori Mountains form a block lodged between two rift arms at this junction (2). The location and composition of Pleistocene to Recent volcanic rocks can be used to constrain models for the uplift of the Rwenzori Mountains that explain uplift by delamination of a lithosphere block beneath the rift (3). Six small volcanic fields are located in the Toro Ankole area east and southeast of Rwenzori; they contain carbonatite either as lava flows or as components in lapilli tuffs, as well as unusual K2O-rich, SiO2-poor melt compositions akin to leucitites and potassic melilitites that increase in importance towards the south. Their major and trace element and Sr-, Nd-, Hf-, and Os-isotope compositions are consistent with a source composed not just of peridotite, but also containing mica- and clinopyroxene-rich ultramafic assemblages (4). The requirement for assemblages of this type is greater than for potassic melilitites and nephelinites further south in the rift, and this agrees with their greater abundance as xenoliths in the lavas of the Toro Ankole area. The xenoliths contain no evidence for metasomatic replacement of pre-existing peridotite minerals, but rather appear to be formed by crystallization as liquidus minerals on the walls of magma channelways within the upper mantle. Some are zoned and contain vein margins, indicating more than one episode of melt infiltration. Re-melting of such assemblages partially meets the geochemical requirements of the volcanics (4) and has been shown to produce melts with similar major element compositions in experiments (5

  10. Late Triassic uplift of southern Norway revealed by detrital zircons in the Norwegian-Danish Basin (United States)

    Olivarius, Mette; Nielsen, Lars H.; Weibel, Rikke; Kristensen, Lars; Thomsen, Tonny B.


    Zircon U/Pb geochronometry is used to identify the sediment source areas of the Upper Triassic to Lower Jurassic shallow marine to paralic Gassum Formation in the Norwegian-Danish Basin. The analyses of zircon grains from geographically and stratigraphically widely distributed cores take advantage of the detailed sequence stratigraphic framework existing for the succession. The zircon ages indicate that the sediment in the lower part of the Gassum Formation in the northern and central parts of the basin was supplied solely from the Telemarkia Terrane in the southern part of southern Norway. However, age signatures from other basement terranes were added during periods of transgression presumably as a result of longshore reworking. The sediment in the eastern part of the basin has a different provenance signature that reflects supply from various sources of which some or all seemingly include older sediments. The basinwide fluvial incision that occurred during a relative sea-level fall in the Rhaetian is interpreted to be related to uplift of southern Norway since a pronounced content of zircon grains with U/Pb ages of 1.65 Ga were introduced in the Norwegian-Danish Basin at the time. This age is dominant in the upper part of the Gassum Formation and is present in all studied younger sediments in the Norwegian-Danish Basin, whereas it is missing in older sediments in the basin. Rocks with corresponding ages are presently exposed in the Jotun Nappe Complex and the Western Gneiss Complex in the central and northern parts of southern Norway. Thus, major faulting activity must have occurred in southern Norway during the Late Triassic that made such rocks available for erosion with permanent southeastwards drainage.

  11. Recycling an uplifted early foreland basin fill: An example from the Jaca basin (Southern Pyrenees, Spain) (United States)

    Roigé, M.; Gómez-Gras, D.; Remacha, E.; Boya, S.; Viaplana-Muzas, M.; Teixell, A.


    In the northern Jaca basin (Southern Pyrenees), the replacement of deep-marine by terrestrial environments during the Eocene records a main drainage reorganization in the active Pyrenean pro-wedge, which leads to recycling of earlier foreland basin sediments. The onset of late Eocene-Oligocene terrestrial sedimentation is represented by four main alluvial fans: Santa Orosia, Canciás, Peña Oroel and San Juan de la Peña, which appear diachronously from east to west. These alluvial fans are the youngest preserved sediments deposited in the basin. We provide new data on sediment composition and sources for the late Eocene-Oligocene alluvial fans and precursor deltas of the Jaca basin. Sandstone petrography allows identification of the interplay of axially-fed sediments from the east with transversely-fed sediments from the north. Compositional data for the alluvial fans reflects a dominating proportion of recycled rock fragments derived from the erosion of a lower to middle Eocene flysch depocentre (the Hecho Group), located immediately to the north. In addition, pebble composition allows identification of a source in the North Pyrenean Zone that provided lithologies from the Cretaceous carbonate flysch, Jurassic dolostones and Triassic dolerites. Thus we infer this zone as part of the source area, located in the headwaters, which would have been unroofed from turbidite deposits during the late Eocene-Oligocene. These conclusions provide new insights on the response of drainage networks to uplift and topographic growth of the Pyrenees, where the water divide migrated southwards to its present day location.

  12. A geomorphic analysis of Sinai's drainage pattern. Evidence for interpreting the distribution of uplift? (United States)

    Oswald, Angela; Stüwe, Kurt; Hanke, Gustav


    A variety of quantitative geomorphologic methods have proven useful to infer aspects of the interplay between tectonics and surface processes and have been applied to various regions in the world. For example, quantitative analysis of drainage systems may be used to investigate the formation of mountain belts where the exposure of bedrock can be linked with tectonic processes. Sinai Peninsula, which is located at the northernmost Red Sea, shows what appears to be a fluvial landscape despite present aridity. Its geomorphology is suitable for a quantitative geomorphologic interpretation using a classic stream power approach. Geomorphologic parameters were derived through analysis of the ASTER digital elevation model (DEM). Steepness and concavity index were extracted from slope-area relationships along channel profiles. Although parameters like knickpoints along channels are typically controlled by complex mechanisms, they may be used to interpret different regimes of uplift. Sinuosity has been calculated from plan channel coordinates in order to differentiate between fluvial and fault dominated channels and channel segments. Because of possible overprinting of fluvial features by present day arid climate erosion and sedimentation processes, the DEM-based analysis needs to be supplemented with photographic images and field observations in order to assess the significance of the single parameter values. The spatial distribution of geomorphic parameter values is compared to the large scale topographic and slope pattern and correlated with the different tectonic regimes acting on Sinai, namely the divergent rifting of the Gulf of Suez in the West and the strike slip dominated opening of the Gulf of Aqaba, whereas Northern Sinai is tilted towards the Mediterranean.

  13. Climate and soil-age constraints on nutrient uplift by plants. (United States)

    Porder, S.; Chadwick, O. A.


    We analyzed changes in nutrient availability and elemental losses from the entire weathering zone at 28 sites arrayed across climatic and soil-age gradients on the island of Hawai'i. The sites are located on three basaltic lava flows (10, 170, and 350 ky) each of which crosses a precipitation gradient from plant nutrient uplift where nutrient cations and phosphorus are retained in upper horizons as a result of plant activity. The gradients also elucidate several abiotic constraints on plant- driven retention of nutrients. At the dry sites (plant slow the loss of nutrient (e.g. potassium) vs. non-nutrient (e.g. sodium) cations, but the effect is small because of low plant cover and productivity. At intermediate rainfall (750 - 1300 mm yr-1) plants substantially enrich both nutrient cations and P in the upper soils, an effect that increases with flow age. In contrast, at high rainfall (>1500 mm yr-1), the effect of plants on nutrient distributions diminishes with soil age and is largely absent after 350 ky of soil development. Unlike the major plant macronutrients, the distribution of the transition metals iron (Fe) and aluminum (Al) is driven more by chemical reactions than by plant uptake. Dry sites exhibit very little movement of either element, even after 350 ky of soil development. However at high rainfall the older flows show substantial Al and Fe translocations, and wet sites on all three flows have increased Al on soil exchange sites. These transition metals are key constituents of the secondary minerals that strongly influence the availability of cations and P to plants. The loss of Fe and Al is highly correlated with the loss of P in the older and wetter sites, and increased Al on exchange sites limits the availability of nutrient cations to plants. Thus redox driven redistribution of Fe and acid solublization of Al place a further abiotic constraint on nutrient retention by plants.

  14. Cenozoic Siliciclastic Sediment Budget of Africa, a Record of the Post-Break Uplift and Aridification (United States)

    Robin, C.; Guillocheau, F.; Baby, G.; Calves, G.


    Siliciclastic sediment budget measurements was performed along the margins and onshore basins of Africa for Cenozoic times. Our objective was (1) to quantify the ratio between onshore and offshore sediment preservation in the case of a relief with mostly no mountain belt and (2) to understand the factors forcing the sediment supply along the passive margins of Africa, uplift or climate changes (with the major aridification of Africa since Middle Miocene). This study is based on basin-scale regional sections (seismic reflection data from industry and academics, wells correlation), calibrated in age and lithology on different types of wells (industry, DSDP/ODP). Most of the effort was on the revaluation of the ages (calibration and uncertainties). The volumes of sediments and uncertainties on depth conversion velocity laws, lithology and ages were measured using software developed by J. Braun (Grenoble University, France). 1. The sediment preserved onshore (750 000 km3) is one of magnitude less than was is preserved offshore 2. The main deformations controlling the sediment supply are (1) the growth or the domes of the East African rift and (2) the marginal bulge of the central and equatorial segments of the South Atlantic Ocean (from southern Angola to Guinea). 3. The aridification of Africa since at least Middle Miocene is very sensitive in the south (fossilization of the relief of the South African Plateau) and in the northwest, with a sharp decrease of the sediment supply. 4. Some buffer effects are very important, for example for the Nile and the Zambezi, where sediments were first stored in onshore basins, Sudan or Malawi rift, and later drained because of a capture (Nile) or a regional stress change (Zambezi).

  15. Crust beneath the northwestern Deccan Volcanic Province, India: Evidence for uplift and magmatic underplating (United States)

    Rao, K. Madhusudhan; Kumar, M. Ravi; Rastogi, B. K.


    The northwestern Deccan Volcanic Province of India and its pericratonic rift basins were reactivated during different stages after the breakup of India from the Gondwanaland and collision with the Asian plate. In this study, we present results of crustal thickness and average crustal Vp/Vs ratios beneath this plume-affected region using common conversion point imaging and H-k stacking analysis of 6893 receiver functions using data from a network comprising 58 broadband seismic stations sited on diverse tectonic terrains. We find large variations in crustal thickness, with the Moho depths varying from 28 to 43 km in the Kachchh rift, 28 to 38 km in the Cambay rift, 39.5-41.5 km in the north and eastern parts of the Cambay rift, and 29 to 39 km in the Saurashtra region and South Gujarat. A Moho upwarp of 6 to 7 km in the Saurashtra region can be attributed to positive buoyancy and uplift due to thermal influx affected by the Reunion plume. High crustal Vp/Vs ratios beneath the Kachchh rift (1.8 to 2.05), coastal areas of Saurashtra (1.75 to 2.06), and North Gujarat (1.81 to 1.85) indicate dominance of a mafic/ultramafic crust. High regional heat flow, high electrical conductivity, large intracrustal S wave velocity reduction, and high average crustal Poisson's ratios are consistent with partial melt related to the process of magmatic underplating in the lower crust. At other stations, the crust appears to be felsic with Vp/Vs ratios in the range of 1.57 to 1.76.

  16. Does slab-window opening cause uplift of the overriding plate? A case study from the Gulf of California (United States)

    Mark, Chris; Chew, David; Gupta, Sanjeev


    Complete subduction of an oceanic plate results in slab-window opening. A key uncertainty in this process is whether the higher heat flux and asthenospheric upwelling conventionally associated with slab-window opening generate a detectable topographic signature in the overriding plate. We focus on the Baja California Peninsula, which incorporates the western margin of the Gulf of California rift. The topography and tectonics of the rift flank along the peninsula are strongly bimodal. North of the Puertecitos accommodation zone, the primary drainage divide attains a mean elevation of ca. 1600 m above sea level (asl), above an asthenospheric slab-window opened by Pacific-Farallon spreading ridge subduction along this section of the trench at ca. 17-15 Ma. To the south, mean topography decreases abruptly to ca. 800 m asl (excluding the structurally distinct Los Cabos block at the southern tip of the peninsula), above fragments of the oceanic Farallon slab which stalled following slab tear-off at ca. 15-14 Ma. Along the peninsula, a low-relief surface established atop Miocene subduction-related volcaniclastic units has been incised by a west-draining canyon network in response to uplift. These canyons exhibit cut-and-fill relationships with widespread post-subduction lavas. Here, we utilise LANDSAT and digital elevation model (DEM) data, integrated with previously published K-Ar and 40Ar/39Ar lava crystallisation ages, to constrain the onset of rift flank uplift to ca. 9-5 Ma later than slab-window formation in the north and ca. 11-10 Ma later in the south. These greatly exceed response time estimates of ca. 2 Ma or less for uplift triggered by slab-window opening. Instead, uplift timing of the high-elevation northern region is consistent with lower-lithospheric erosion driven by rift-related convective upwelling. To the south, stalled slab fragments likely inhibited convective return flow, preventing lithospheric erosion and limiting uplift to the isostatic response

  17. The central uplift of Elorza Crater: Insights into its geology and possible relationships to the Valles Marineris and Tharsis regions (United States)

    Hopkins, R. T.; Tornabene, L. L.; Osinski, G. R.


    The majority of hydrated silicate occurrences on Mars are associated with impact craters (Ehlmann et al., 2011; Carter et al., 2013). Three formation mechanisms have been suggested to account for this correlation: (1) aqueous alteration occurred pre-impact, and was subsequently exposed via the impact (pre-impact; Bibring et al., 2006; Ehlmann et al., 2011), (2) heat generated from the impact facilitated the formation of a hydrothermal system, leading to alteration products (syn-impact; e.g. Marzo et al., 2010; Osinski et al., 2013), and/or (3) altered materials were deposited after crater formation, or formed within the crater well after the impact had taken place (post-impact). In this study, we analyze the central uplift of Elorza Crater, a ∼40 km diameter impact crater located ∼300 km north of Valles Marineris. To determine whether hydrated minerals found within the uplift were generated pre-, syn-, or post-impact, we used a data synthesis approach, utilizing High Resolution Imaging Science Experiment (HiRISE), Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), Context Camera (CTX), and Thermal Emission Imaging System (THEMIS) imagery. Opaline silica is observed in two locations on the southwestern side of the uplift and is interpreted to have been pre-existing or formed via hydrothermal alteration due to stratigraphic relationships with the overlying impact melt unit. Both Fe/Mg smectite and low-calcium pyroxene (LCP) are found throughout the uplift. Bedrock exposures on the northern wall of Coprates Chasma containing Fe/Mg smectite and LCP suggest an uplifted origin for these units. In all cases, although a pre-existing origin is probable, it is difficult to rule out the possibility of an impact-generated hydrothermal origin. Using the observed stratigraphy exposed in Coprates Chasma and bedrock exposures analyzed in nearby craters, we were able to constrain the pre-impact stratigraphy around Elorza. The near-subsurface consists of Hesperian

  18. Coastal uplift west of Algiers (Algeria): pre- and post-Messinian sequences of marine terraces and rasas and their associated drainage pattern (United States)

    Authemayou, Christine; Pedoja, Kevin; Heddar, Aicha; Molliex, Stéphane; Boudiaf, Azzedine; Ghaleb, Bassam; Van Vliet Lanoe, Brigitte; Delcaillau, Bernard; Djellit, Hamou; Yelles, Karim; Nexer, Maelle


    The North Africa passive margin is affected by the ongoing convergence between the African and Eurasian plates. This convergence is responsible for coastal uplift, folding, and reverse faulting on new and reactivated faults on the margin. The active deformation is diffuse and thus rather difficult to locate precisely. We aim to determine how a coastal landscape evolve in this geodynamic setting and gain insights into active tectonics. More particularly, we evidence and quantify coastal uplift pattern of the Chenoua, Sahel, and Algiers reliefs (Algeria), using sequences of marine terraces and rasas and computing several morphometric indices from the drainage pattern. Upper and Middle Pleistocene uplift rates are obtained by fossil shoreline mapping and preliminary U/Th dating of associated coastal deposits. Extrapolation of these rates combined to analyses of sea-level referential data and spatial relationships between marine terraces/rasas and other geological markers lead us to tentatively propose an age for the highest coastal indicators (purported the oldest). Values of morphometric indices showing correlations with uplift rate allow us to analyze uplift variation on area devoid of coastal sequence. Geological and geomorphological data suggest that coastal uplift probably occurred since the Middle Miocene. It resulted in the emergence of the Algiers massif, followed by the Sahel ridge massif. The Sahel ridge has asymmetrically grown by folding from west to east and was affected by temporal variation of uplift. Compared to previous study, the location of the Sahel fold axis has been shifted offshore, near the coast. The Chenoua fault vertical motion does not offset significantly the coastal sequence. Mean apparent uplift rates and corrected uplift rates since 120 ka are globally steady all along the coast with a mean value of 0.055 ± 0.015 mm/year (apparent) and of 0.005 ± 0.045 mm/year (corrected for eustasy). Mean apparent coastal uplift rates between 120 and

  19. The timing of uplift, volcanism, and rifting peripheral to the Red Sea: A case for passive rifting? (United States)

    Bohannon, Robert G.; Naeser, Charles W.; Schmidt, Dwight L.; Zimmermann, Robert A.


    Prior to the formation of the Red Sea the northeastern Afro/Arabian continent had low relief and was largely below sea level from the Late Cretaceous to the early Oligocene. The events leading to the formation of the Red Sea followed the sequence (1) alkaline volcanism and rifting beginning about 30-32 Ma affecting a narrow linear zone in the continent, (2) rotational block faulting and detachment faulting, well underway by 25 Ma, (3) gabbro and diorite magmatism, andesite to rhyolite volcanism, and fine-grained nonmarine sedimentation in the rift between 20 and 25 Ma, (4) fine-grained marine sedimentation in the rift as the early shelves started to subside in the middle Miocene, and (5) uplift of the adjacent continents (about 3 km) and subsidence of the shelves (about 4 km) between 13.8 and 5 Ma. The youth of the uplift is suggested by 44 fission track dates on apatites from rocks of the Proterozoic Arabian Shield that range in age from 13.8 to 568 Ma. The youngest of these ages, coupled with the present high relief along the Arabian escarpment and published heat flow measurements, indicate that 2.5-4 km uplift has occurred in the last 13.8 m.y. The sequence volcanism/rifting followed by uplift leads to our adoption of a passive mantle model for rift origin. Models that require uplift to create the rift are rejected, because of the late uplift. We advocate a model of lithospheric extension caused by two-dimensional plate stress over those requiring tractional drag at the base of the lithosphere caused by vigorous flow in the asthenosphere. It is acknowledged that traction models could explain the observed data, but they imply a rigid, static lithosphere and seem to require a link between the direction of flow in the asthenosphere and plate motions. Neither requirement is necessary in the extension model. The rift starts with mechanical extension in a narrow zone of lithosphere between 25-32 Ma in our model. The thinned lithosphere is replaced by upwelling

  20. A Low-velocity Finger from Iceland beneath Southern Scandinavia - the Key to Understanding Neogene Uplift? (United States)

    Weidle, C.; Maupin, V.


    A model of upper mantle S-wave velocity beneath northwestern Europe is presented, based on a tomography of regional surface wave observations. Data from international and, more importantly, regional data archives (including temporary deployments) were used to measure group velocities for both Love and Rayleigh surface waves. The procedure for data selection, group velocity measurements and inversion for group velocity 2-D maps follows closely the one described by Levshin et al. (GJI, 170, 441-459, 2007). Our new set of group velocity maps differs significantly from global reference maps, enhancing many details and amplitudes of group velocity variations in the study region. We then apply a linear inversion scheme to invert for 1-D shear wave velocity profiles which are assembled to a 3-D model. By choosing conservative regularization parameters in the 2-D inversion we ensure the smoothness of the group velocity maps and the resulting 3-D shear wave speed model. To account for the different tectonic regimes in the study region, we compare inversions with 3 different reference models (pure 1-D, 3-D crust / 1-D mantle and pure 3-D) to investigate the sensitivity of the 1-D inversions to inaccuracies in crustal models. We find that all three models are consistent at depths below 90 km and the resulting models deviate only slightly from each other, mostly in amplitudes. We image an intriguing low-velocity anomaly extending from the Iceland plume domain across the north Atlantic beneath southern Scandinavia between 70-150 km depth. Beneath southern Norway, the negative perturbations reach a maximum of up to 13 % w.r.t. ak135 and a shallowing of the anomaly is indicated. This observation could explain the sustained uplift of southern Scandinavia in Neogene times, but the mechanisms are yet undetermined. Furthermore, our upper mantle model reveals good alignment to ancient plate boundaries and first-order crustal fronts around the triple junction of the Baltica

  1. Paleomagnetism of Lower Permian Abo and Yeso Formation, Carizzo Arroyo, Lucero Uplift, New Mexico (United States)

    Petronis, M. S.; Geissman, J. W.


    We report paleomagnetic data from Lower Permian hematite-cemented sandstones and siltstones from Carrizo Arroyo, on the eastern edge of the Lucero uplift along the west-side of the middle Rio Grande rift, to test the hypothesis that the rift margins have accommodated extensional strain via vertical axis rotation. In addition, we present a revised interpretation of the structural setting and deformation history of the area, were late-Tertiary transtensional stresses have produced the majority of the structures in the area. The paleomagnetic data are discussed in the context of this hypothesis. In the Rio Grande rift area, a mid-Cenozoic and younger extensional feature defining the eastern margin of the Colorado Plateau, relatively little work has been done to assess the magnitude and sense of vertical axis rotations of fault-bounded crustal blocks within and at the margins of the plateau. A growing body of evidence shows that the Colorado Plateau has experienced some degree of vertical axis rotation and some magnitude of northward translation, although the magnitudes of the rotation and translation have been subject to considerable debate. Eight to ten oriented samples from 50 sites have been fully demagnetized with all sites yielding interpretable results: 41 sites from three sections in the Lower Permian Abo Formation, and 9 sites in the Meseta Blanca Member of the overlying Yeso Formation. In most cases, progressive thermal demagnetization resulted in a nearly univectorial decay of the magnetization to the origin that is well grouped at the site level. After correcting for modest dip of strata, the 50 sites in Carrizo Arroyo yield an estimate group mean (D = 162.1°, I = -4.1°, α95 = 6.8°, k = 10.18). Overall, the data from this part of the west side of the rift are discordant, in a clockwise since, with Early Permian (about D = 140°, I = -2.0°) and mid-Permian (about D = 145°, I = -4.0°) expected directions. We interpret the paleomagnetic data from

  2. National Assessment of Oil and Gas Project - Raton Basin-Sierra Grande Uplift Province (041) Boundary (United States)

    U.S. Geological Survey, Department of the Interior — The USGS Central Region Energy Team assesses oil and gas resources of the United States. The onshore and State water areas of the United States comprise 71...

  3. Mesozoic and Cenozoic uplift and exhumation of the Bogda Mountain, NW China: Evidence from apatite fission track analysis

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    Wenhao Tang


    Full Text Available Apatite fission track (AFT analysis on samples collected from a Paleozoic series is used to constrain the cooling history of the Bogda Mountain, northwest China. AFT ages range from 136.2 to 85.6 Ma and are younger than rock depositional ages and the mean confined track lengths (11.0–13.2 μm mostly showing unimodal distribution are shorten, indicating significant track-annealing. Thermal histories modeling based on the distribution of fission-track lengths combined with the regional geological data show that two rapid cooling phases occurred in the latest Jurassic–early Cretaceous and the Oligocene–Miocene. Those new data together with previous published data show that the AFT ages become younger from the southwest to northeast in the western Bogda Mountain and its adjacent areas. The fission-track ages of the southwest area are relatively older (>100 Ma, recording the earlier rapid uplift phase during the late Jurassic–Cretaceous, while the ages in the north piedmont of the Bogda Mountain (namely the northeast part are younger (<60 Ma, mainly reflecting the later rapid uplift phase in the Oligocene–Miocene. The trend of younger AFT ages towards the northeast might be explained by post-Cretaceous large-scale crustal tilting towards the southwest. In the thrust fault-dominated northern limbs of the Bogda Mountain, AFT ages reveal a discontinuous pattern with age-jumps across the major fault zones, showing a possible strata tilting across each thrust faults due to the thrust ramps during the Cenozoic. The two rapid uplift stages might be related to the accretion and collision in the southern margin of the Asian continent during the late Jurassic and late Cenozoic, respectively.

  4. Uplift, rupture, and rollback of the Farallon slab reflected in volcanic perturbations along the Yellowstone adakite hot spot track (United States)

    Camp, Victor E.; Ross, Martin E.; Duncan, Robert A.; Kimbrough, David L.


    Field, geochemical, and geochronological data show that the southern segment of the ancestral Cascades arc advanced into the Oregon back-arc region from 30 to 20 Ma. We attribute this event to thermal uplift of the Farallon slab by the Yellowstone mantle plume, with heat diffusion, decompression, and the release of volatiles promoting high-K calc-alkaline volcanism throughout the back-arc region. The greatest degree of heating is expressed at the surface by a broad ENE-trending zone of adakites and related rocks generated by melting of oceanic crust from the Farallon slab. A hiatus in eruptive activity began at ca. 22-20 Ma but ended abruptly at 16.7 Ma with renewed volcanism from slab rupture occurring in two separate regions. The eastern rupture resulted in the extrusion of Steens Basalt during the ascent and melting of a dry mantle (plume) source contaminated with depleted mantle. The contemporaneous western rupture resulted in renewed subduction, melting of a wet mantle source, and the rejuvenation of high-K calc-alkaline volcanism near the Nevada-California border at 16.7 Ma. Here the initiation of slab rollback is evident in the westward migration of arc volcanism at 7.8 km/Ma. Today, the uplifted slab is largely missing beneath the Oregon back-arc region, replaced instead by a seismic hole that is bound on the south by the adakite hot spot track. We attribute slab destruction to thermal uplift and mechanical dislocation that culminated in rapid tearing of the slab from 17-15 Ma and possible foundering and sinking of slab segments from 16 to 10 Ma.

  5. Regional earthquakes followed by delayed ground uplifts at Campi Flegrei Caldera, Italy: Arguments for a causal link (United States)

    Lupi, Matteo; Frehner, Marcel; Weis, Philipp; Skelton, Alasdair; Saenger, Erik H.; Tisato, Nicola; Geiger, Sebastian; Chiodini, Giovanni; Driesner, Thomas


    Earthquake-triggered volcanic activity promoted by dynamic and static stresses are considered rare and difficult-to-capture geological processes. Calderas are ideal natural laboratories to investigate earthquake-volcano interactions due to their sensitivity to incoming seismic energy. The Campi Flegrei caldera, Italy, is one of the most monitored volcanic systems worldwide. We compare ground elevation time series at Campi Flegrei with earthquake catalogues showing that uplift events at Campi Flegrei are associated with large regional earthquakes. Such association is supported by (yet non-definitive) binomial tests. Over a 70-year time window we identify 14 uplift events, 12 of them were preceded by an earthquake, and for 8 of them the earthquake-to-uplift timespan ranges from immediate responses to 1.2 yr. Such variability in the response delay may be due to the preparedness of the system with faster responses probably occurring in periods during which the Campi Flegrei system was already in a critical state. To investigate the process that may be responsible for the proposed association we simulate the propagation of elastic waves and show that passing body waves impose high dynamic strains at the roof of the magmatic reservoir of the Campi Flegrei at about 7 km depth. This may promote a short-lived embrittlement of the magma reservoir's carapace otherwise marked by a ductile behaviour. Such failure allows magma and exsolved volatiles to be released from the magmatic reservoir. The fluids, namely exsolved volatiles and/or melts, ascend through a nominally plastic zone above the magmatic reservoir. This mechanism and the associated inherent uncertainties require further investigations but the new concept already implies that geological processes triggered by passing seismic waves may become apparent several months after passage of the seismic waves.

  6. Recognition of Pleistocene marine terraces in the southwest of Portugal (Iberian Peninsula: evidences of regional Quaternary uplift

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    Paula M. Figueiredo


    Full Text Available Southwest mainland Portugal is located close to the Eurasia-Nubia plate boundary and is characterized by moderate seismicity, although strong events have occurred as in 1755 (Mw≥8, 1969, (Mw 7.9, and more recently in 2007 (Mw 5.9 and 2009 (Mw 5.5, all located in the offshore. No historical earthquakes with onshore rupture are known for this region. At the coastline, high sea cliffs, incised drainages, emergent marine abrasion platforms and paleo sea cliffs indicate that this region is undergoing uplift, although no morphological features were found that could be unequivocally associated with the 1755 mega earthquake. To better understand the recent tectonic activity in this sector of Iberia, it is necessary not only to analyze active structures on land, but also to search for evidence for deformation that may relate to inferred offshore active structures. We thus conducted a study of marine terraces along the coastline to identify regional vertical crustal motions. Several poorly preserved surfaces with thin sedimentary deposits, comprising old beach sediments, were recognized at elevations starting at 2 m elevation and rising inland up to a regional abrasion platform situated at about 120 m a.s.l.. We identified distinct paleo sea level references at several locations at consistent elevations. This terrace sequence is likely Late Pleistocene in age, with individual platforms correlative to MIS 5 high stands and is coherent with a long-term slow uplift of the littoral zone for the southwest of Portugal. Although dating of discrete platforms is an ongoing and difficult task, preliminary correlations of paleo-shoreline elevations suggest that the uplift rate is in the range of 0.1-0.2 mm/yr.

  7. Coseismic slip and early afterslip of the 2015 Illapel, Chile, earthquake: Implications for frictional heterogeneity and coastal uplift (United States)

    Barnhart, William D.; Murray, Jessica R.; Briggs, Richard W.; Gomez, Francisco; Miles, Charles P. J.; Svarc, Jerry L.; Riquelme, Sebástian; Stressler, Bryan J.


    Great subduction earthquakes are thought to rupture portions of the megathrust, where interseismic coupling is high and velocity-weakening frictional behavior is dominant, releasing elastic deformation accrued over a seismic cycle. Conversely, postseismic afterslip is assumed to occur primarily in regions of velocity-strengthening frictional characteristics that may correlate with lower interseismic coupling. However, it remains unclear if fixed frictional properties of the subduction interface, coseismic or aftershock-induced stress redistribution, or other factors control the spatial distribution of afterslip. Here we use interferometric synthetic aperture radar and Global Position System observations to map the distribution of coseismic slip of the 2015 Mw 8.3 Illapel, Chile, earthquake and afterslip within the first 38 days following the earthquake. We find that afterslip overlaps the coseismic slip area and propagates along-strike into regions of both high and moderate interseismic coupling. The significance of these observations, however, is tempered by the limited resolution of geodetic inversions for both slip and coupling. Additional afterslip imaged deeper on the fault surface bounds a discrete region of deep coseismic slip, and both contribute to net uplift of the Chilean Coastal Cordillera. A simple partitioning of the subduction interface into regions of fixed frictional properties cannot reconcile our geodetic observations. Instead, stress heterogeneities, either preexisting or induced by the earthquake, likely provide the primary control on the afterslip distribution for this subduction zone earthquake. We also explore the occurrence of coseismic and postseismic coastal uplift in this sequence and its implications for recent hypotheses concerning the source of permanent coastal uplift along subduction zones.

  8. Uplift and tilting of the Shackleton Range in East Antarctica driven by glacial erosion and normal faulting (United States)

    Paxman, Guy J. G.; Jamieson, Stewart S. R.; Ferraccioli, Fausto; Bentley, Michael J.; Forsberg, Rene; Ross, Neil; Watts, Anthony B.; Corr, Hugh F. J.; Jordan, Tom A.


    Unravelling the long-term evolution of the subglacial landscape of Antarctica is vital for understanding past ice sheet dynamics and stability, particularly in marine-based sectors of the ice sheet. Here we model the evolution of the bedrock topography beneath the Recovery catchment, a sector of the East Antarctic Ice Sheet characterized by fast-flowing ice streams that occupy overdeepened subglacial troughs. We use 3-D flexural models to quantify the effect of erosional unloading and mechanical unloading associated with motion on border faults in driving isostatic bedrock uplift of the Shackleton Range and Theron Mountains, which are flanked by the Recovery, Slessor, and Bailey ice streams. Inverse spectral (free-air admittance) and forward modeling of topography and gravity anomaly data allow us to constrain the effective elastic thickness of the lithosphere (Te) in the Shackleton Range region to 20 km. Our models indicate that glacial erosion, and the associated isostatic rebound, has driven 40-50% of total peak uplift in the Shackleton Range and Theron Mountains. A further 40-50% can be attributed to motion on normal fault systems of inferred Jurassic and Cretaceous age. Our results indicate that the flexural effects of glacial erosion play a key role in mountain uplift along the East Antarctic margin, augmenting previous findings in the Transantarctic Mountains. The results suggest that at 34 Ma, the mountains were lower and the bounding valley floors were close to sea level, which implies that the early ice sheet in this region may have been relatively stable.

  9. History of Asian eolian input to the Sea of Japan since 15 Ma: Links to Tibetan uplift or global cooling? (United States)

    Shen, Xingyan; Wan, Shiming; France-Lanord, Christian; Clift, Peter D.; Tada, Ryuji; Révillon, Sidonie; Shi, Xuefa; Zhao, Debo; Liu, Yanguang; Yin, Xuebo; Song, Zehua; Li, Anchun


    We present high-resolution analyses of clay mineral assemblages combined with analysis of Sr-Nd-Pb isotopic compositions of the changes in Asian eolian input to the basin since 15 Ma. The clay mineral assemblages at IODP Site U1430 mainly consist of smectite (∼51%) and illite (∼36%), with minor kaolinite (∼7%) and chlorite (∼6%). Provenance analysis suggests that the fine-grained sediment at the study site is a two end-member mixture of eolian dust from Central Asia and fluvial input from the Japanese islands. The Central Asian end member supplied illite-rich and high 87Sr/86Sr and low εNd(0) eolian dust to the study site by wind, while the Japanese end member, characterized by young volcanic rocks, contributed smectite-rich, low 87Sr/86Sr and high εNd(0) weathering products via rivers. The ratio of illite/smectite and εNd(0) values of clay-sized silicate sediments at Site U1430 were used as proxies for tracing the changing strength of central Asian eolian input to the Sea of Japan, and thus reconstruct the aridification history of its source region. Our study presents for the first time a continuous, high-resolution record that highlights the four-step drying of Central Asia that occurred at ∼11.8 Ma, 8 Ma, 3.5 Ma and 1.2 Ma. Considered the nature and timing of major climatic and tectonic events in Asia, we conclude that the strengthened aridification of Central Asia starting at ∼11.8 Ma was possibly driven by the combined effect of Tibetan surface uplift and global cooling, whereas the rapid drying at ∼8 Ma was caused primarily by the uplift of the northern Tibetan Plateau. In contrast, global cooling, overwhelming the influence of Tibetan Plateau uplift, has become the primary control on Central Asia aridification since ∼3.5 Ma.

  10. Using Arrested Solid-Solid Multiphase Reactions in Geological Materials to Deduce the Rate of Crustal Uplift

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    Glassley, W.E.; Meike, A.


    The history geological terrains experience can be traced as a series of temperature and pressure changes. Each change drives the system toward a new state of thermodynamic equilibrium. The resultant overprinted rock fabrics, textures and chemical heterogeneities can be difficult to interpret. However, if carefully chosen, features from the scale of kilometers to nanometers can be used to reconstruct the history of mountain systems. Uplift of the Sri Lankan Central Highlands was rapid enough to preserve well-developed symplectite textures, some of which represent arrested solid-state diffusion-controlled reactions of garnet + O{sub 2} to form orthopyroxene + plagioclase + magnetite, as the rocks were exhumed from over 30 km in the earth's crust. Our objective has been to determine the reaction mechanisms responsible for symplectite development, and to establish the time interval over which these reactions occurred, to constrain the rate of mountain uplift. Considering that the most rapid mechanism is solid state grain-boundary diffusion of oxygen, the reaction time can be constrained by bounding the rate of oxygen supply to the reaction site. The solid state grain boundary diffusion rate of oxygen has been inferred to be ca. 10{sup -14}m{sup 2}-sec (Farver and Yund, 1991), but is sensitive to inferred grain boundary width. The range of rates thus determined allows the distinction between rapid uplift similar to that of the Himalayan Mountains, and the slow and progressive erosion of a less dramatic terrain. Further constraints on diffusion control and energetic relationships are determined from crystallographic relationships between the reactant and product phases, and submicron scale microstructure.

  11. Oligocene - modern paleoenvironmental change in of the Peruvian central Andes: Implications for late Miocene uplift and aridification (United States)

    Sundell, K. E.; Saylor, J. E.; Lapen, T. J.; Villarreal, D. P.; Styron, R. H.; Usnayo Perales, W. P.; Cárdenas, J.


    Elevation and development of rainshadows play a first-order control on the paleoenvironment of hinterland basins. Understanding which of several factors may be driving paleoenvironmental changes is therefore central to understanding the interplay between topography and climate of orogenic plateaus. Late Cenozoic basins in the Peruvian Western Cordillera, situated deep in the rainshadow of the modern Andean plateau, are valuable yet largely unexplored archives of past environments. The Tincopalca-Huacochullo Basin in this region is a rare example of well-preserved, largely undeformed, Oligocene - Miocene stratigraphy that spans a critical time in the development of the Andean plateau. We present results from stable isotopic analysis of ancient water preserved in rhyolitic glass in the context of newly logged stratigraphy, temporally controlled by new zircon U-Pb ages, and compare these results to the stable isotopic signatures of modern stream water samples. Results show a decrease in δD values from -90 to -100‰ synchronous with a change from a dominantly fluvial to evaporitic lacustrine depositional environment in the late Oligocene - early Miocene. This is followed by an abrupt middle - late Miocene change in δD values between -160 and -170‰ coincident with deposition of voluminous volcanic stratigraphy. Finally, late Miocene - modern δD values increase to -105 - -120‰ during slowed arc volcanism. Modern waters feature relatively high d excess (δD - 8*δ18O) of 1 to 9‰. These findings are consistent with 1) slow late Oligocene - Miocene uplift between moderate (2 - 3 km) elevations, 2) either a middle - late Miocene change in moisture source, or increased rate of surface uplift; the latter is our preferred hypothesis, and 3) increasing aridity from late Miocene - present as uplift of the Altiplano, Eastern Cordillera and Subandes pushes this region deeper into the orogenic rainshadow.

  12. The 17 Ma old Turkana beaked whale fossil: new paleoaltimetry constraints for uplift and environmental change in East Africa (United States)

    Wichura, Henry; Jacobs, Louis L.; Strecker, Manfred R.; Lin, Andrew; Polcyn, Michael J.; Manthi, Fredrick K.; Winkler, Dale A.; Matthew, Clemens


    Timing and magnitude of vertical motions of the Earth's crust is key to evaluate the impact of tectonic processes on changes in atmospheric circulation patterns, rainfall, and environmental conditions. The East African Plateau (EAP) is a major topographic feature that fundamentally impacts the patterns of the Indian-African Monsoon and the eastward transport of air masses from the Congo Basin. Uplift of the EAP in Kenya has been linked to mantle processes, but due to the lack of reliable palaeoaltimetric data it has been challenging to unambiguously constrain plateau evolution, vertical motions associated with late Cenozoic rifting of the East African Rift System, and ensuing environmental change. We explored the fossil remains of a beaked whale (Ziphiidae) from the Turkana region in the northern Kenya Rift, 700 km inland from the present-day coastline of the Indian Ocean. The whale fossil, preserved near sea level, was discovered at an elevation of 620 m and thus constrains the uplift of the northeastern flanks of the EAP. The Kenyan ziphiid was discovered in fluvio-lacustrine sediments of the extensional Oligo-Miocene Lokichar basin (Mead, 1975) along with terrestrial mammals and freshwater molluscs below a basalt dated at 17.1 ± 1.0 Ma (Boschetto et al., 1992). The unifying characteristics of riverine occurrences of modern marine mammals include sufficient discharge in low-gradient rivers to maintain pathways deep enough to facilitate migration, and the absence of shallow bedrock, rapids, and waterfalls. The most likely route, which may have had these characteristics is a fluvial corridor controlled by protracted thermal subsidence of the Cretaceous Anza Rift, which once linked extensional processes in Central and East Africa with the continental margin of northeastern Africa. The fossil locality and analogies with present-day occurrences of marine mammals in terrestrial realms suggest that the ziphiid stranded slightly above sea level. In combination with

  13. Focused rock uplift above the subduction décollement at Montague and Hinchinbrook Islands, Prince William Sound, Alaska (United States)

    Ferguson, Kelly M; Armstrong, Phillip A; Arkle Jeanette C,; Haeussler, Peter J.


    Megathrust splay fault systems in accretionary prisms have been identified as conduits for long-term plate motion and significant coseismic slip during subduction earthquakes. These fault systems are important because of their role in generating tsunamis, but rarely are emergent above sea level where their long-term (million year) history can be studied. We present 32 apatite (U-Th)/He (AHe) and 27 apatite fission-track (AFT) ages from rocks along an emergent megathrust splay fault system in the Prince William Sound region of Alaska above the shallowly subducting Yakutat microplate. The data show focused exhumation along the Patton Bay megathrust splay fault system since 3–2 Ma. Most AHe ages are younger than 5 Ma; some are as young as 1.1 Ma. AHe ages are youngest at the southwest end of Montague Island, where maximum fault displacement occurred on the Hanning Bay and Patton Bay faults and the highest shoreline uplift occurred during the 1964 earthquake. AFT ages range from ca. 20 to 5 Ma. Age changes across the Montague Strait fault, north of Montague Island, suggest that this fault may be a major structural boundary that acts as backstop to deformation and may be the westward mechanical continuation of the Bagley fault system backstop in the Saint Elias orogen. The regional pattern of ages and corresponding cooling and exhumation rates indicate that the Montague and Hinchinbrook Island splay faults, though separated by only a few kilometers, accommodate kilometer-scale exhumation above a shallowly subducting plate at million year time scales. This long-term pattern of exhumation also reflects short-term seismogenic uplift patterns formed during the 1964 earthquake. The increase in rock uplift and exhumation rate ca. 3–2 Ma is coincident with increased glacial erosion that, in combination with the fault-bounded, narrow width of the islands, has limited topographic development. Increased exhumation starting ca. 3–2 Ma is interpreted to be due to rock uplift

  14. A review about the mechanisms associated with active deformation, regional uplift and subsidence in southern South America (United States)

    Folguera, Andrés; Gianni, Guido; Sagripanti, Lucía; Rojas Vera, Emilio; Novara, Iván; Colavitto, Bruno; Alvarez, Orlando; Orts, Darío; Tobal, Jonathan; Giménez, Mario; Introcaso, Antonio; Ruiz, Francisco; Martínez, Patricia; Ramos, Victor A.


    A broad range of processes acted simultaneously during the Quaternary producing relief in the Andes and adjacent foreland, from the Chilean coast, where the Pacific Ocean floor is being subducted beneath South American, to the Brazilian and the Argentinean Atlantic platform area. This picture shows to be complex and responds to a variety of processes. The Geoid exemplifies this spectrum of uplift mechanisms, since it reflects an important change at 35°S along the Andes and the foreland that could be indicating the presence of dynamic forces modeling the topography with varying intensity through the subduction margin. On the other hand, mountains uplifted in the Atlantic margin, along a vast sector of the Brazilian Atlantic coast and inland regions seem to be created at the area where the passive margin has been hyper-extended and consequently mechanically debilitated and the forearc region shifts eastwardly at a similar rate than the westward advancing continent. Therefore the forearc at the Arica latitudes can be considered as relatively stationary and dynamically sustained by a perpendicular-to-the-margin asthenospheric flow that inhibits trench roll back, determining a highly active orogenic setting at the eastern Andes in the Subandean region. To the south, the Pampean flat subduction zone creates particular conditions for deformation and rapid propagation of the orogenic front producing a high-amplitude orogen. In the southern Central and Patagonian Andes, mountain (orogenic) building processes are attenuated, becoming dominant other mechanisms of exhumation such as the i) impact of mantle plumes originated in the 660 km mantle transition, ii) the ice-masse retreat from the Andes after the Pleistocene producing an isostatic rebound, iii) the dynamic topography associated with the opening of an asthenospheric window during the subduction of the Chile ridge and slab tearing processes, iv) the subduction of oceanic swells linked to transform zones and v) the

  15. Effects of Mountain Uplift and Climatic Oscillations on Phylogeography and Species Divergence in Four Endangered Notopterygium Herbs

    Directory of Open Access Journals (Sweden)

    Khurram Shahzad


    Full Text Available Mountain uplift and climatic fluctuations are important driving forces that have affected the geographic distribution and population dynamics history of organisms. However, it is unclear how geological and climatic events might have affected the phylogeographic history and species divergence in high-alpine herbal plants. In this study, we analyzed the population demographic history and species differentiation of four endangered Notopterygium herbs on the high-altitude Qinghai–Tibetan Plateau (QTP and adjacent areas. We combined phylogeographic analysis with species distribution modeling to detect the genetic variations in four Notopterygium species (N. incisum, N. franchetii, N. oviforme, and N. forrestii. In total, 559 individuals from 74 populations of the four species were analyzed based on three maternally inherited chloroplast fragments (matK, rbcL, and trnS-trnG and one nuclear DNA region (internal transcribed spacer, ITS. Fifty-five chloroplast DNA (cpDNA and 48 ITS haplotypes were identified in the four species. All of the cpDNA and ITS haplotypes were species-specific, except N. franchetii and N. oviforme shared one cpDNA haplotype, H32. Phylogenetic analysis suggested that all four species formed a monophyletic clade with high bootstrap support, where N. franchetii and N. oviforme were sisters. In addition, each Notopterygium species generated an individual clade that corresponded to their respective species in the ITS tree. Population dynamics analyses and species distribution modeling showed that the two widely distributed herbs N. incisum and N. franchetii exhibited obvious demographic expansions during the Pleistocene ice ages. Molecular dating suggested that the divergence of the four Notopterygium species occurred approximately between 3.6 and 1.2 Mya, and it was significantly associated with recent extensive uplifts of the QTP. Our results support the hypothesis that mountain uplift and Quaternary climatic oscillations

  16. Temporal Controls on Uplift and Slip Rates for the Puente Hills and Santa Ana Mountains, Southern Los Angeles Basin, Orange County, California (United States)

    Gath, E. M.; Grant, L. B.; Owen, L. A.


    The Puente Hills (PH) are seismically active and tectonically uplifted by the Puente Hills Blind Thrust fault (PHBTF). The rate of uplift, and consequently, the late Quaternary slip rate of the eastern part of the PHBTF, herein named the Santa Ana segment, can be constrained by mapping and dating Quaternary stream terraces and strath surfaces in the Santa Ana River Canyon. The PH are cut by the 2-3 mm/yr right-lateral Whittier fault, itself capable of M6.7-7.2 earthquakes. The 7 mapped terraces and strath surfaces of the PH are cut by the Whittier fault with minimal vertical separation. OSL dating, soil age estimates, and correlation with sea level highstands constrains the PH uplift rate to 0.6-1.4 mm/yr based on OSL dates, and 0.2-0.8 mm/yr from other methods. The rates overlap in the range 0.6-0.8 mm/yr, and we propose that this is the most reliable estimate of uplift rate because it is based on several methods. An uplift rate of 0.6-0.8 mm/yr for the PH is also consistent with a 500 700 ka emergent age based on our geomorphic analysis of PH drainage basin development. Using a 30° dip angle produces a slip rate on the Santa Ana segment of the PHBTF of 1.2-1.6 mm/yr. Preliminary tectonic geomorphic analysis of the Santa Ana Mountains (SAM) suggests that they too are being uplifted and are probably seismically active. Shorelines preserved on the lower foothills of Peralta and Loma Ridges were correlated to eustatic sea levels for age estimations. Mapping and dating of terraces in the Santiago Creek drainage, and the older marine terraces indicates that the SAM are uplifting at 0.2-0.7 mm/yr, probably due to a blind thrust associated with partial termination of the Elsinore fault.

  17. Everyday experiences of women posttreatment after breast cancer: the role of uncertainty, hassles, uplifts, and coping on depressive symptoms. (United States)

    Taha, Sheena Aislinn; Matheson, Kimberly; Anisman, Hymie


    Considerable research has examined the experiences of women at risk, during diagnosis, and throughout treatment of breast cancer; however, less in known about these women posttreatment. Many women report dealing with extensive long-standing ailments such as lymphedema and fatigue, as well as a fear of illness recurrence. However, women posttreatment also report finding benefit and meaning from their cancer occurrence. These orthogonal outcomes may be related to the uncertainty an individual is able to tolerate. Thus, this online study examined Canadian women who completed treatment for breast cancer (n = 42), and women in a control condition (n = 42), responses to the daily experience of hassles and uplifts, intolerance of uncertainty, coping strategies, and depressive symptoms. Although depressive symptoms and daily hassles did not differ between the two groups of women, women with a previous cancer experience reported a greater amount and frequency of daily uplifts, and hassle intensity predicted fewer depressive symptoms among women posttreatment compared to healthy controls. Furthermore, hassle intensity mediated the relationship between intolerance of uncertainty and depressive symptoms, but only for women in the control condition. Last, for women posttreatment only, the use of emotion-focused coping to deal with a fear of cancer recurrence mediated the relationship between intolerance of uncertainty and depressive symptoms, whereas problem-focused, avoidant, or cognitive-restructuring coping strategies did not. These results point to the need to provide resources to women posttreatment, but also that those women who survive breast cancer can obtain benefits from the experience.

  18. U-Pb systematics of pre-Cambrian carbonates: The Riphean Sukhaya Tunguska Formation in the Turukhansk Uplift, Siberia

    Energy Technology Data Exchange (ETDEWEB)

    Ovchinnikova, G.V.; Gorokhov, I.M.; Belyatskii, B.V. [Institute of Pre-Cambrian Geology and Geochronology, St. Petersburg (Russian Federation)] [and others


    A brief review of the geochemistry of U, Th, and Pb in oceanic water and marine carbonates is given, and the U-Th-Pb systematics in limestones and dolomites of the Sukhaya Tunguska Formation in the Turukhansk Uplift is studied. The analysis of phases with different solubilities in ammonium acetate and hydrochloric acid and the plotting of available results along the {sup 207}Pb/{sup 204}Pb-{sup 206}Pb/{sup 204}Pb coordinates yield an age of 1035{plus_minus}60 Ma. This value matches the stratigraphic position of the Sukhaya Tunguska Formation rocks at the Middle-Late Riphean boundary and may be interpreted as the age of an early diagenesis of sediments. Evidence for the temporal compatibility of the processes of sedimentation, dolomitization, and early diagenesis is provided. Isotope-geochemical data, which indicate a recent uranium loss by carbonate rocks, are in good agreement with results of the study of Cenozoic evolution in the Turukhansk Uplift. The average {sup 238}U/{sup 204}Pb value (8.22) calculated for the source of the Sukhaya Tunguska carbonate deposits suggests that Pb from mantle sources or a relatively young crust was abundant in the near-contact fluid phase that governed the composition of carbonate rocks 1035{plus_minus}60 Ma ago.

  19. HALO aircraft measurements of East Asian anthropogenic SO2 import into the lower stratosphere by a warm conveyor belt uplift (United States)

    Schlager, H.; Arnold, F.; Aufmhoff, H.; Baumann, R.; Pirjola, L.; Roiger, A.; Sailer, T.; Wirth, M.; Schumann, U.


    We report on a case study of anthropogenic SO2 pollution transport into the lower stratosphere from East Asian source regions. The pollution layer was observed over Central Europe by measurements from the new German research aircraft HALO. The layer contained enhanced SO2, HNO3 and water vapor and caused increased Lidar backscatter radiation. Meteorological analysis and air mass transport and dispersion model simulations reveal that the detected pollutants were released from ground-based sources in East-China, South-Korea, and Japan. The pollution plume was uplifted by a warm conveyor belt associated with a West-Pacific cyclone and finally injected into the lower stratosphere. Our HALO measurements were performed 5 days after the air mass uplift event, when significant parts of the Northern Hemisphere were already covered by the pollution plume. Accompanying trajectory chemistry and aerosol box model simulations indicate that H2SO4/H2O aerosol droplets were generated in the SO2-rich plume and grew to sizes large enough to explain the observed increased Lidar backscatter signal. Implications of the SO2 transport pathway into the lower stratosphere presented in this study will be discussed.

  20. Fine sediment sources in coastal watersheds with uplifted marine terraces in northwest Humboldt County, California (United States)

    Stephen Sungnome Madrone; Andrew P. Stubblefield


    Erosion in the Mill and Luffenholtz Creek watersheds in Humboldt County, California, with their extensive clay soils, can lead to high turbidity levels in receiving bodies of water, increasing the costs of treating water for domestic water supplies. Detailed road and erosion surveys and monitoring of suspended sediment, discharge, and turbidity levels in Mill Creek (3....

  1. Metamorphic fluids and uplift-erosion history of a portion of the Kapuskasing structural zone, Ontario, as deduced from fluid inclusions (United States)

    Rudnick, R. L.; Ashwal, L. D.; Henry, D. J.


    Fluid inclusions can be used to determine the compositional evolution of fluids present in high grade metamorphic rocks (Touret, 1979) along with the general P-T path followed by the rocks during uplift and erosion (Hollister et al., 1979). In this context, samples of high grade gneisses from the Kapuskasing structural zone (KSZ, Fig. 1) of eastern Ontario were studied in an attempt to define the composition of syn- and post-metamorphic fluids and help constrain the uplift and erosion history of the KSZ. Recent work by Percival (1980), Percival and Card (1983) and Percival and Krogh (1983) shows that the KSZ represents lower crustal granulites that form the lower portion of an oblique cross section through the Archean crust, which was up faulted along a northeast striking thrust fault. The present fluid inclusion study places constraints upon the P-T path which the KSZ followed during uplift and erosion.

  2. Strain data recorded in Xinjiang and their bearing on Tianshan’s uplift/shortening and Tarim basin’s rotation

    Directory of Open Access Journals (Sweden)

    Jiang Jingxiang


    Full Text Available Based on the continuous strain data recorded in Xinjiang since 1985, we discuss the mechanisms of Tianshan’s uplift and Tarim basin’s clockwise rotation. The results indicate; 1 The principal – compression directions in Tianshan are nearly NS, and their intersection angles with regional structures and mountains are nearly perpendicular, which is in accordance with Tianshan’s uplift and crustal shortening. 2 The principal compressions around Tarim basin tend to facilitate the regional faults’ left-lateral strike-slip movements and the basin’s clockwise rotation. These phenomena of uplift/shortening and rotation are fundamentally the results of India plate’s northward push on Euro-Asia plate, and the associated Pamir arc’s rapid northward movement and regional blocks’ interaction.

  3. Timing and driving mechanisms for multi-stage uplift of the Southern Rocky Mountains: Evidence from thermochronology and detrital zircon analysis (United States)

    Donahue, M. S.; Ricketts, J. W.; Karlstrom, K. E.; Kelley, S.


    A compilation of apatite fission track (AFT) and (U-Th)/He (AHe) thermochronologic data from the southern Rocky Mountains reveals spatial and temporal patterns in Cenozoic cooling corresponding to discrete uplift pulses: 1) 70-45 Ma cooling ages are best preserved in hangingwall blocks of Laramide uplifts, especially in the northern Rockies with apparent exhumation rates (AER) of ~ 60 m/Ma based on age-elevation transects and modeled cooling paths; 2) Relative tectonic quiescence from 45-35 Ma coincided with the establishment of the Rocky Mountain erosion surface; 3) 35-25 Ma cooling ages variably overprint Laramide cooling histories south of central Colorado and much of the Great Plains topographic ramp; this episode had apparent exhumation rates of ~100 m/Ma and was driven by heating and mantle buoyancy during the ignimbrite flare-up concentrated beneath the San Juan and Mogollon Datil volcanic fields, with associated long wavelength uplift in central Colorado; 4) 20-10 Ma shorter wavelength uplifts in Rio Grande rift flanks at rates of ~ 150 m/Ma from Wyoming to Mexico in response to simultaneous opening of the Rio Grande rift; 5) Ongoing post-10 Ma uplift at rates > 120 m/Ma especially in areas of faulting and areas overlying marked mantle velocity transitions due to small scale upper mantle convection and response to land surface uplift, river integration, and isostatic rebound due to differential erosion. To investigate the sedimentary record of mid-Tertiary events, detrital zircon analysis of the Telluride Conglomerate and Blanco Basin Formation of the western and southeastern flanks of the San Juan volcanic field reveals youngest grain clusters of 28 Ma and 33 Ma, respectively. These units record unroofing, first of Paleozoic sedimentary units, then Proterozoic basement and Oligocene volcanics. AHe of these units constrains burial to less than 1-1.5 km. We interpret these units to record the uplift and erosion associated with the inflating San Juan volcanic

  4. Uplifting of carbon monoxide from biomass burning and anthropogenic sources to the free troposphere in East Asia (United States)

    Ding, Ke; Liu, Jane; Ding, Aijun; Liu, Qiang; Zhao, Tianliang; Shi, Jiancheng; Han, Yong; Wang, Hengmao; Jiang, Fei


    East Asia has experienced rapid development with increasing carbon monoxide (CO) emission in the past decades. Therefore, uplifting CO from the boundary layer to the free troposphere in East Asia can have great implications on regional air quality around the world. It can also influence global climate due to the longer lifetime of CO at higher altitudes. In this study, three cases of high CO episodes in the East China Sea and the Sea of Japan from 2003 to 2005 are examined with spaceborne Measurements of Pollution in the Troposphere (MOPITT) data, in combination with aircraft measurements from the Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC) program. Through analyses of the simulations from a chemical transport model GEOS-Chem and a trajectory dispersion model FLEXPART, we found different CO signatures in the elevated CO and distinct transport pathways and mechanisms for these cases.

  5. Post-tectonic landscape evolution in NE Iberia using staircase terraces: Combined effects of uplift and climate (United States)

    Lewis, Claudia J.; Sancho, Carlos; McDonald, Eric V.; Peña-Monné, José Luis; Pueyo, Emilio L.; Rhodes, Edward; Calle, Mikel; Soto, Ruth


    River incision into bedrock resulting from the combined effects of tectonic uplift and climate governs long-term regional landscape evolution. We determined spatial and temporal patterns of post-orogenic stream incision from a sequence of well-preserved staircase terraces developed over the last 1 Ma in the Central Pyrenees and its southern foreland Ebro basin (NE Spain). Extensive remnants of ten vertically separated terraces (Qt1 to Qt10, from oldest to youngest) were mapped along 170 km of the Cinca River valley, transverse to the Pyrenean mountain belt. Multiple outcrops appear in the upper reach of the valley (Ainsa sector, 50 km from headwaters) as well as in the lower reach (Albalate sector, 125 km from headwaters). Fluvial incision into bedrock was calculated using (i) differentially corrected GPS measurements of the altitude of straths and (ii) numerical dating of alluvial sediments from the lower terraces (Qt5 to Qt9) by Optically Stimulated Luminescence, previously reported by Lewis et al. (2009), and supplemented with new dates for the upper terraces (Qt1, Qt2 and Qt3) based on paleomagnetism and supported by soil development. Considering altitude differences and the elapsed time between successive well preserved terrace couples (Qt3-Qt7, Qt7-Qt9 and Qt9-Active channel), mean bedrock incision rates ranged from 0.76 to 0.38 m ka- 1, at the upper reach of the valley (Ainsa section), and from 0.61 to 0.20 m ka- 1, at the lower reach (Albalate section). River incision along the valley produced vertically separated, near-parallel longitudinal terrace profiles evidencing a rapid near-uniform regional uplift as response to (i) the tectonic lithospheric thickening in NE Iberia and (ii) the erosional download rebound related to the Ebro basin exorheism. Moreover, a subtle upstream divergence of strath profiles may have been a consequence of an increase in uplift rate toward the head of the valley. Additionally, incision rates changed over time as indicate

  6. Fracture Mechanics Models for Brittle Failure of Bottom Rails due to Uplift in Timber Frame Shear Walls

    Directory of Open Access Journals (Sweden)

    Joergen L. Jensen


    Full Text Available In partially anchored timber frame shear walls, hold-down devices are not provided; hence the uplift forces are transferred by the fasteners of the sheathing-to-framing joints into the bottom rail and via anchor bolts from the bottom rail into the foundation. Since the force in the anchor bolts and the sheathing-to-framing joints do not act in the same vertical plane, the bottom rail is subjected to tensile stresses perpendicular to the grain and splitting of the bottom rail may occur. This paper presents simple analytical models based on fracture mechanics for the analysis of such bottom rails. An existing model is reviewed and several alternative models are derived and compared qualitatively and with experimental data. It is concluded that several of the fracture mechanics models lead to failure load predictions which seem in sufficiently good agreement with the experimental results to justify their application in practical design.

  7. ROCK PHYSICS. Rock physics of fibrous rocks akin to Roman concrete explains uplifts at Campi Flegrei Caldera. (United States)

    Vanorio, Tiziana; Kanitpanyacharoen, Waruntorn


    Uplifts in the Campi Flegrei caldera reach values unsurpassed anywhere in the world (~2 meters). Despite the marked deformation, the release of strain appears delayed. The rock physics analysis of well cores highlights the presence of two horizons, above and below the seismogenic area, underlying a coupled process. The basement is a calc-silicate rock housing hydrothermal decarbonation reactions, which provide lime-rich fluids. The caprock above the seismogenic area has a pozzolanic composition and a fibril-rich matrix that results from lime-pozzolanic reactions. These findings provide evidence for a natural process reflecting that characterizing the cementitious pastes in modern and Roman concrete. The formation of fibrous minerals by intertwining filaments confers shear and tensile strength to the caprock, contributing to its ductility and increased resistance to fracture. Copyright © 2015, American Association for the Advancement of Science.

  8. Rapid ice unloading in the Fleming Glacier region, southern Antarctic Peninsula, and its effect on bedrock uplift rates

    DEFF Research Database (Denmark)

    Zhao, Chen; King, Matt A.; Watson, Christopher S.


    m at the front of Fleming Glacier. Using IceBridge and ICESat-2/GLAS data spanning 2002–2014, we show an increased rate of mean ice-surface lowering, with rates post-2008 more than twice those of 2002–2008. We use these load change data as a basis for the simulation of viscoelastic solid Earth...... deformation. We subtract modeled elastic deformation rates, and a suite of modeled viscous rates, from GPS-derived three-dimensional bedrock velocities at sites to the south of Fleming Glacier to infer properties of Earth rheology. Assuming the pre-breakup bedrock uplift was positive due to post-Last Glacial...... the Fleming Glacier, after the application of elastic and plate tectonic corrections, point away from Marguerite Bay rather than the present glacier front. This suggests that horizontal motion in the region reflects the earlier retreat of the glacier system following the LGM, compatible with a relatively...

  9. Magnetotelluric impedance tensor analysis for identification of transverse tectonic feature in the Wagad uplift, Kachchh, northwest India (United States)

    Pavan Kumar, G.; Kumar, Virender; Nagar, Mehul; Singh, Dilip; Mahendar, E.; Patel, Pruthul; Mahesh, P.


    The 2001 Bhuj earthquake (Mw 7.7) occurred in northwestern region of Indian peninsula has reactivated a couple of transverse faults to its surroundings. Intermediate to moderate magnitude earthquakes are occurring along these faults which includes recent Dholavira earthquake (Mw 5.1, 2012) suggesting distinct tectonic scenario in the region. We present the results of magnetotelluric (MT) impedance tensors analyses of 18 sites located along a profile cutting various faults in the uplifted Wagad block of the Kachchh basin. The MT time series of 4-5 days recording duration have been processed and the earth response functions are estimated in broad frequency range (0.01-1000 s). The observed impedance tensors are analyzed by using three decomposition techniques as well as by the phase tensor method constraining with the induction arrows. The analyses suggest distinct tectonic feature within the block bounded by the South Wagad Fault (SWF) and the North Wagad Fault (NWF) particularly in the period band of 1-10 s. In the south of NWF, the telluric vectors and the major axes of the phase ellipses are aligned in the NNW-SSE to NW-SE direction where as a dominant E-W strike is obtained for northern side of the NWF. The transverse geo-electric strike coincides with the prominent clustering of seismicity after the Bhuj earthquake and trend of the Manfara transverse fault is located in close vicinity of the study area. We therefore suggest the presence NNW-SSE trending transverse structural feature in the Wagad uplift of the basin appears to play significant role in the current seismicity of the active intraplate region.

  10. Phylogeography of Cephalotaxus oliveri (Cephalotaxaceae) in relation to habitat heterogeneity, physical barriers and the uplift of the Yungui Plateau. (United States)

    Wang, C B; Wang, T; Su, Y J


    Habitat heterogeneity, physical barriers, and the uplift of the Yungui Plateau were found to deeply affect the phylogeographic pattern and evolutionary history of Cephalotaxus oliveri, a perennial conifer endemic to China. In this study, we explored the phylogeography using three chloroplast sequences (trnL-trnF, trnT-trnD and atpB-rbcL) in 22 natural populations of C. oliveri distributed throughout its range. The Yungui Plateau populations of C. oliveri were revealed to origin ca. 9.15Ma by molecular clock estimation, which is consistent with rapid uplift of the Qinghai-Tibetan Plateau (QTP) ca. 8-10Ma. Additionally, geological effects of the Yungui Plateau were suggested to promote the rapid intra-specific differentiation of C. oliveri in the Pliocene and Early Pleistocene. The relatively low level of genetic diversity (h=0.719, θ=1.17×10(-3)) and high population differentiation (NST=0.771 and GST=0.642) implied restricted gene flow among populations, which was confirmed by the Nested Clade Analysis (NCA). Mismatch distribution and haplotypes network provided evidences of recent demographic population expansion. Furthermore, the statistical dispersal-vicariance analysis indicated that the center of origin was in Central China. The comparison of haplotype distribution patterns indicated that the regions of HNHPS and HBLD were the potential refugia during the Pleistocene ice ages. Our results highlighted that habitat heterogeneity and physical barriers presenting in a species range can predict genetic patterns. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. The uplift of the southern Sierra Nevada, the Isabella Anomaly and Death Valley extension: A single geodynamic process? (United States)

    Le Pourhiet, L.; Gurnis, M.; Saleeby, J.


    Within the last decade, a variety of evidence for the recent removal of a garnet pyroxenite root of the Sierra Nevada has been inferred from both geochemical analysis of mantle xenoliths and geophysical imaging of the upper mantle and Moho. As the density associated with this mineralogical assemblage (3500 kg m-3) is larger than the density of the surrounding mantle peridotite (3300 kg m-3) gravitational instability is believed to have triggered the foundering of the Southern Sierra Nevada range. Simple models exist to describe gravitational instabilities (linear or non linear Rayleigh Taylor, RT, instability, i.e. Diapirism). However, for reasonable geothermal constraints and creep parameter for earth materials, RT models do not explain: 1) the long stability of the root (90 Myr, or 25 Myr since Farallon plate subduction resumed), 2) its rapid removal (1-3 Myr), and 3) the quantity of uplift. In order to establish new mechanical models that allow gravitational instabilities to develop slowly and be removed within the critical timescale fixed by the simultaneity of uplift and onset of Plio- Quaternary volcanism in the southern Sierra at 3Myr, we carried out a systematic study of the influence of the strength of the lower crust on the mode of instability by means of thermo-mechanical models that allow thermo-chemical convection and plastic softening. We found that models with a strong crust remain stable as predicted by RT models. However, we found models which did destabilize and explain: the fast timescale of the removal, the formation of the Sierra Nevada micro-plate at 10 Ma, and the extension in the Death Valley area at 15 Ma within the framework of one single mantle instability. Those models also explain the current layered seismic structure of Isabella Anomaly and its dip towards the south east.

  12. Simulation of CO2 Sequestration at Rock Spring Uplift, Wyoming: Heterogeneity and Uncertainties in Storage Capacity, Injectivity and Leakage

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Hailin [Los Alamos National Laboratory; Dai, Zhenxue [Los Alamos National Laboratory; Jiao, Zunsheng [Wyoming State Geological Survey; Stauffer, Philip H. [Los Alamos National Laboratory; Surdam, Ronald C. [Wyoming State Geological Survey


    Many geological, geochemical, geomechanical and hydrogeological factors control CO{sub 2} storage in subsurface. Among them heterogeneity in saline aquifer can seriously influence design of injection wells, CO{sub 2} injection rate, CO{sub 2} plume migration, storage capacity, and potential leakage and risk assessment. This study applies indicator geostatistics, transition probability and Markov chain model at the Rock Springs Uplift, Wyoming generating facies-based heterogeneous fields for porosity and permeability in target saline aquifer (Pennsylvanian Weber sandstone) and surrounding rocks (Phosphoria, Madison and cap-rock Chugwater). A multiphase flow simulator FEHM is then used to model injection of CO{sub 2} into the target saline aquifer involving field-scale heterogeneity. The results reveal that (1) CO{sub 2} injection rates in different injection wells significantly change with local permeability distributions; (2) brine production rates in different pumping wells are also significantly impacted by the spatial heterogeneity in permeability; (3) liquid pressure evolution during and after CO{sub 2} injection in saline aquifer varies greatly for different realizations of random permeability fields, and this has potential important effects on hydraulic fracturing of the reservoir rock, reactivation of pre-existing faults and the integrity of the cap-rock; (4) CO{sub 2} storage capacity estimate for Rock Springs Uplift is 6614 {+-} 256 Mt at 95% confidence interval, which is about 36% of previous estimate based on homogeneous and isotropic storage formation; (5) density profiles show that the density of injected CO{sub 2} below 3 km is close to that of the ambient brine with given geothermal gradient and brine concentration, which indicates CO{sub 2} plume can sink to the deep before reaching thermal equilibrium with brine. Finally, we present uncertainty analysis of CO{sub 2} leakage into overlying formations due to heterogeneity in both the target saline

  13. Expanding the efficacy of Project UPLIFT: Distance delivery of mindfulness-based depression prevention to people with epilepsy. (United States)

    Thompson, Nancy J; Patel, Archna H; Selwa, Linda M; Stoll, Shelley C; Begley, Charles E; Johnson, Erica K; Fraser, Robert T


    Depression affects about 16% of the U.S. population over a lifetime. People with chronic diseases have especially high rates of comorbid depression; 32% to 48% of people with epilepsy experience depression. This study evaluated the efficacy of a mindfulness-based cognitive therapy intervention for preventing major depressive disorder (MDD) episodes in people with epilepsy. Participants (n = 128) were adults from Georgia, Michigan, Texas, and Washington with epilepsy and mild/moderate depressive symptoms. The 8-session weekly Project UPLIFT intervention, based on mindfulness-based cognitive therapy, was group-delivered via Web or telephone. Using a randomized, controlled crossover design, participants were assigned to Project UPLIFT or a treatment-as-usual (TAU) waitlist and assessed at baseline, and after intervening in the intervention group (∼10 weeks) and in the TAU group (∼20 weeks). Assessments included valid self-report measures of depression and MDD, knowledge/skills, and satisfaction with life. The incidence of MDD episodes (new or relapse) from baseline to interim assessment was significantly lower in the intervention condition (0.0%) than in TAU (10.7%). Depressive symptoms decreased significantly more in the intervention condition than in TAU; Web and telephone did not differ. Change in knowledge/skills mediated the effect, which persisted over the 10 weeks of follow-up. Knowledge/skills and life satisfaction increased significantly more in the intervention condition than in TAU. Distance delivery of group mindfulness-based cognitive therapy can prevent episodes of MDD, reduce symptoms of depression, and increase life satisfaction in people with epilepsy. This intervention is easily modified for persons with other chronic diseases and other disparity populations. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

  14. Asphalt features and gas accumulation mechanism of Sinian reservoirs in the Tongwan Palaeo-uplift, Sichuan Basin

    Directory of Open Access Journals (Sweden)

    Wei Li


    Full Text Available Breakthroughs have been made in natural gas exploration in Sinian reservoirs in the Tongwan Palaeo-uplift, Sichuan Basin, recently. However, there are disputes with regard to the genetic mechanisms of natural gas reservoirs. The development law of asphalts in the Sinian reservoirs may play an extremely important role in the study of the relationships between palaeo oil and gas reservoirs. Accordingly, researches were conducted on the features and development patterns of asphalts in the Sinian reservoirs in this area. The following research results were obtained. (1 Asphalts in the Sinian reservoirs were developed after the important hydrothermal event in the Sichuan Basin, namely the well-known Emei Taphrogeny in the mid-late Permian Period. (2 Distribution of asphalts is related to palaeo oil reservoirs under the control of palaeo-structures of Indosinian-Yanshanian Period, when the palaeo-structures contained high content of asphalts in the high positions of the palaeo-uplift. (3 Large-scale oil and gas accumulations in the Sinian reservoirs occurred in the Indosinian-Yanshanian Period to generate the Leshan-Ziyang and Gaoshiti-Moxi-Guang'an palaeo oil reservoirs. Cracking of crude oil in the major parts of these palaeo oil reservoirs controlled the development of the present natural gas reservoirs. (4 The development of asphalts in the Sinian reservoirs indicates that hydrocarbons in the Dengying Formation originated from Cambrian source rocks and natural gas accumulated in the Sinian reservoirs are products of late-stage cracking of the Sinian reservoirs. (5 The Sinian palaeo-structures of Indosinian-Yanshanian Period in the Sichuan Basin are favorable regions for the development of the Sinian reservoirs, where discoveries and exploration practices will play an important role in the era of Sinian natural gas development in China.

  15. Variations of Lateral Bedrock Erosion Rates Control Planation of Uplifting Folds in the Foreland of the Tian Shan, NW China (United States)

    Bufe, Aaron; Burbank, Douglas W.; Liu, Langtao; Bookhagen, Bodo; Qin, Jintang; Chen, Jie; Li, Tao; Thompson Jobe, Jessica A.; Yang, Huili


    Fluvial planation surfaces, such as straths, commonly serve as recorders of climatic and tectonic changes and are formed by the lateral erosion of rivers, a process that remains poorly understood. Here we present a study of kilometer-wide, fluvially eroded, low-relief surfaces on rapidly uplifting folds in the foreland of the southwestern Tian Shan. A combination of field work, digital elevation model analysis, and dating of fluvial deposits reveals that despite an arid climate and rapid average rock-uplift rates of 1-3 mm/yr, rivers cut extensive (>1-2 km wide) surfaces with typical height variations of 2-6 kyr. The extent of this "beveling" varies in space and time, such that different beveling episodes affect individual structures. Between times of planation, beveled surfaces are abandoned, incised, and deformed across the folds. In a challenge to models that link strath cutting and abandonment primarily to changes in river incision rates, we demonstrate that lateral erosion rates of antecedent streams crossing the folds have to vary by more than 1 order of magnitude to explain the creation of beveled platforms in the past and their incision at the present day. These variations do not appear to covary with climate variability and might be caused by relatively small (much less than an order of magnitude) changes in sediment or water fluxes. It remains uncertain in which settings variations in lateral bedrock erosion rates predominate over changes in vertical erosion rates. Therefore, when studying fluvial planation and strath terraces, variability of both lateral and vertical erosion rates should be considered.

  16. Pliocene-Pleistocene climate change, sea level and uplift history recorded by the Horingbaai fan-delta, NW Namibia (United States)

    Stollhofen, Harald; Stanistreet, Ian G.; von Hagke, Christoph; Nguno, Anna


    Its location on a tectonically relatively stable passive margin and its degree of interaction with the sea make the Horingbaai fan-delta, NW Namibia, an exceptional record of coastal activity, providing insights into the response of ephemeral fluvial systems to changes in climate, sea level and continent-scale uplift. The fan comprises upper, middle and lower segments. The upper fan and middle fan are dominated by a braided river system; only in the upper fan are fluvial sediments interleaved with hyperconcentrated flow deposits. Plio-Pleistocene sea level highstands have left marine terraces on the fan surface which enable correlation with the offshore marine record and provide timelines to constrain fan growth. The bulk of fan-delta progradation took place at ∼ 2.7-2.4 Ma, between the formation of a widespread erosional surface incising the middle Pliocene Karpfenkliff and Kamberg Formations, but prior to the emplacement of the warm-water fauna-bearing late Pliocene "Oyster Terrace" (∼ 2.4-2.2 Ma), an equivalent of the + 30 mP (marine terrace package) in coastal southwestern Africa. Major fan progradation is contemporaneous with widespread regional uplift (~ 12 ± 5 m/Ma) and climate change in southwestern Africa, the latter associated with intensification of northern hemisphere glaciations. Younger fan growth phases are weaker and constrained by < 10 m asl marine terrace bodies that yield mostly cold-water fauna, corresponding to the onset of strong glacial/interglacial climatic fluctuations superimposed on a general aridification trend and the introduction of colder sea-surface temperatures after 2.2 Ma.

  17. Climate-dependent fluvial architecture and processes on a suborbital timescale in areas of rapid tectonic uplift: an example from the NE Tibetan Plateau

    NARCIS (Netherlands)

    Wang, X.; Vandenberghe, J.F.; Yi, S; van Balen, R.T.; Lu, H.


    The substantial tectonic uplift (1000-2500. m in a few million years) of the Northeastern Tibetan Plateau (NETP), together with the major climatic changes during the Quaternary, provides an opportunity to study the impact of tectonic and climatic changes on the morphological development and

  18. Upper-plate splay fault earthquakes along the Arakan subduction belt recorded by uplifted coral microatolls on northern Ramree Island, western Myanmar (Burma) (United States)

    Shyu, J. Bruce H.; Wang, Chung-Che; Wang, Yu; Shen, Chuan-Chou; Chiang, Hong-Wei; Liu, Sze-Chieh; Min, Soe; Aung, Lin Thu; Than, Oo; Tun, Soe Thura


    Upper-plate structures that splay out from the megathrusts are common features along major convergent plate boundaries. However, their earthquake and tsunami hazard potentials have not yet received significant attention. In this study, we identified at least one earthquake event that may have been produced by an upper-plate splay fault offshore western Myanmar, based on U-Th ages of uplifted coral microatolls. This event is likely an earthquake that was documented historically in C.E. 1848, with an estimated magnitude between 6.8 and 7.2 based on regional structural characteristics. Such magnitude is consistent with the observed co-seismic uplift amount of ∼0.5 m. Although these events are smaller in magnitude than events produced by megathrusts, they may produce higher earthquake and tsunami hazards for local coastal communities due to their proximity. Our results also indicate that earthquake events with co-seismic uplift along the coast may not necessarily produce a flight of marine terraces. Therefore, using only records of uplifted marine terraces as megathrust earthquake proxies may overlook the importance of upper-plate splay fault ruptures, and underestimate the overall earthquake frequency for future seismic and tsunami hazards along major subduction zones of the world.

  19. The Paleozoic tectonothermal evolution of the Bachu Uplift of the Tarim Basin, NW China: Constraints from (U-Th)/He ages, apatite fission track and vitrinite reflectance data (United States)

    Qiu, Nansheng; Jiang, Guang; Mei, Qinghua; Chang, Jian; Wang, Shengjun; Wang, Jiyang


    This study uses a new application of the apatite and zircon (U-Th)/He thermochronometry technique to investigate the thermal history and tectonic uplift of sedimentary basins. Based on measured apatite and zircon (U-Th)/He ages, apatite fission track data and equivalent vitrinite reflectance measurements of borehole core samples, the thermal history of the Bachu Uplift of the Tarim Basin was modeled. Our analysis indicates a complicated thermal history in the Bachu Uplift region during the Paleozoic. The thermal gradient initially increased from 28-30 °C/km in the Cambrian period to 30-33 °C/km in the Ordovician period and increased up to 33-34 °C/km in the Silurian period. The thermal gradient began to decrease during the Devonian period and was estimated to be approximately 30 °C/km during the Late Devonian and the Early Carboniferous periods. The low thermal gradient phase was followed by an additional high gradient phase from the Late Carboniferous to the Early Permian when the gradient was approximately 32 °C/km. Thermal gradients in the Paleozoic were substantially different than the present-day gradient (21 °C/km). Tectonothermal modeling results also revealed uplift events in the Bachu Uplift region that shifted from south to north (e.g., ˜150 Ma to ˜100 Ma) and from west to east (e.g., ˜250 Ma to ˜150 Ma). This thermal evolution of the Bachu Uplift is consistent with its tectonic progression. The thermal spike in the Late Carboniferous and Early Permian periods could be related to magmatic activities in the Early Permian period. The Paleozoic thermal history of the Bachu Uplift region of the Tarim Basin could not be reconstructed properly due to a lack of reliable thermal indicators in the Lower Paleozoic successions, and a poor understanding of the thermal evolution of Lower Paleozoic source rocks during the Paleozoic has hindered petroleum exploration in this area. This study provides a new Paleozoic thermal history and shows that the Paleozoic

  20. Calculation of regional geomorphic indices to constrain the mechanisms of tectonic uplift and active deformation of the Island of Puerto Rico (United States)

    Martinez, S.


    The island of Puerto Rico in the northern Caribbean covers an area of about 14,000 km2 and is 180 km long and 65 km wide and is densely populated by 3.4 million persons. The island is mountainous with an east-west-trending, central mountain range with its highest point of 1338 m in the geographic center of the island. Previous workers have suggested that the origin of this east-west, Central Cordillera is active uplift and folding of a large, east-west-trending anticline whose fold axis is coincident with the topographic crest of the Cordillera Central. The folding mechanism has been attributed by previous workers to obliquely-subducting slabs of the North American and Caribbean plates beneath the island. To test the hypothesis that this topographic and structural axis is also the axis of active topographic uplift, I created a knickpoint density map for the island based on over 50 different river systems to reveal areas of active uplift. The knickpoint map shows an excellent correlation with the proposed arch both in width and trend of the axis and supports the conclusion that the arch is the main axis of active uplift on the Island. I also calculated geomorphic indices for 21 different watersheds of the island that include the Hypsometric Integral and a Stream Length Gradient Index that both assess tectonic activity based on stream and watershed behaviors. The Hack index and Hypsometric Integral show that the most active area of uplift is located in the central and north-central parts of the island that include about one half of the length of the proposed, east-west-trending arch. The two topographically-elevated ends of the arch in the western and eastern parts of the island are less active, according to the indices. Lower values in these areas may be influenced by higher amounts of precipitations in these areas.

  1. Late Quaternary uplift along the North America-Caribbean plate boundary: Evidence from the sea level record of Guantanamo Bay, Cuba (United States)

    Muhs, Daniel; Schweig, Eugene S.; Simmons, Kathleen; Halley, Robert B.


    The tectonic setting of the North America-Caribbean plate boundary has been studied intensively, but some aspects are still poorly understood, particularly along the Oriente fault zone. Guantanamo Bay, southern Cuba, is considered to be on a coastline that is under a transpressive tectonic regime along this zone, and is hypothesized to have a low uplift rate. We tested this by studying emergent reef terrace deposits around the bay. Reef elevations in the protected, inner part of the bay are ∼11–12 m and outer-coast, wave-cut benches are as high as ∼14 m. Uranium-series analyses of corals yield ages ranging from ∼133 ka to ∼119 ka, correlating this reef to the peak of the last interglacial period, marine isotope stage (MIS) 5.5. Assuming a span of possible paleo-sea levels at the time of the last interglacial period yields long-term tectonic uplift rates of 0.02–0.11 m/ka, supporting the hypothesis that the tectonic uplift rate is low. Nevertheless, on the eastern and southern coasts of Cuba, east and west of Guantanamo Bay, there are flights of multiple marine terraces, at higher elevations, that could record a higher rate of uplift, implying that Guantanamo Bay may be anomalous. Southern Cuba is considered to have experienced a measurable but modest effect from glacial isostatic adjustment (GIA) processes. Thus, with a low uplift rate, Guantanamo Bay should show no evidence of emergent marine terraces dating to the ∼100 ka (MIS 5.3) or ∼80 ka (MIS 5.1) sea stands and results of the present study support this.

  2. Late Quaternary uplift along the North America-Caribbean plate boundary: Evidence from the sea level record of Guantanamo Bay, Cuba (United States)

    Muhs, Daniel R.; Schweig, Eugene S.; Simmons, Kathleen R.; Halley, Robert B.


    The tectonic setting of the North America-Caribbean plate boundary has been studied intensively, but some aspects are still poorly understood, particularly along the Oriente fault zone. Guantanamo Bay, southern Cuba, is considered to be on a coastline that is under a transpressive tectonic regime along this zone, and is hypothesized to have a low uplift rate. We tested this by studying emergent reef terrace deposits around the bay. Reef elevations in the protected, inner part of the bay are ∼11-12 m and outer-coast, wave-cut benches are as high as ∼14 m. Uranium-series analyses of corals yield ages ranging from ∼133 ka to ∼119 ka, correlating this reef to the peak of the last interglacial period, marine isotope stage (MIS) 5.5. Assuming a span of possible paleo-sea levels at the time of the last interglacial period yields long-term tectonic uplift rates of 0.02-0.11 m/ka, supporting the hypothesis that the tectonic uplift rate is low. Nevertheless, on the eastern and southern coasts of Cuba, east and west of Guantanamo Bay, there are flights of multiple marine terraces, at higher elevations, that could record a higher rate of uplift, implying that Guantanamo Bay may be anomalous. Southern Cuba is considered to have experienced a measurable but modest effect from glacial isostatic adjustment (GIA) processes. Thus, with a low uplift rate, Guantanamo Bay should show no evidence of emergent marine terraces dating to the ∼100 ka (MIS 5.3) or ∼80 ka (MIS 5.1) sea stands and results of the present study support this.

  3. Cooling history of the Upper Cretaceous Palgongsan Granite, Gyeongsang Basin, SE Korea and its tectonic implication for uplift on the active continental margin (United States)

    Lim, Hyoun Soo; Lee, Yong Il


    Apatite and zircon fission track analyses were carried out to reconstruct the cooling and inferred uplift history of the Cretaceous Palgongsan Granite, Gyeongsang Basin, Korea. The Palgongsan Granite is one of the Bulguksa intrusive rocks that formed by arc-related plutonism during Late Cretaceous to Early Tertiary time. Fission track dating of the Palgongsan Granite yielded nearly concordant ages of 53 and 65 Ma for apatite and zircon, respectively. The Palgongsan Granite also shows a simple cooling pattern, which suggests that it has not been affected by any thermal event after emplacement. The cooling history derived from fission track data combined with other thermochronometric data indicates that the Palgongsan Granite experienced relatively rapid cooling in earlier stage (> 30 °C/Ma). The initial rapid cooling rate during the Late Cretaceous has been caused by the large thermal contrast between the granite body and the country rocks. After reaching thermal equilibrium with the surrounding country rocks, the cooling rate of the Palgongsan Granite was abruptly decreased in late stage. In this late stage, the decelerated cooling rate is interpreted to have been controlled by uplift and erosion processes, and the average exhumation rate is calculated to be ca. 50 m/my over the temperature range from 100 °C to the surface temperature. The cooling history of the Palgongsan Granite is in good agreement with that of the Ryoke Granitic Belt in Southwest Japan, as well as those of the Taebaeksan Range and other Bulguksa intrusive rocks in the Gyeongsang Basin. This suggests that such cooling was probably caused by regional uplift and exhumation processes on the East Asian active continental margin. Compared with the uplift rates of the Andes, the uplift rates on the eastern Pacific margin appear to be higher than those on the western Pacific margin.

  4. Tectonic geomorphology of the 21 May 2003 Zemmouri earthquake area (Mw 6.8, Tell Atlas, Algeria) : An analysis of the long-term coastal uplift (United States)

    Bagdi-Issaad, Souhila; Meghraoui, Mustapha; Nedjari, Ahmed


    Geomorphological, geological and structural markers attest for successive uplift during the late Quaternary along the Algerian coastal region, a section of the Africa-Eurasia plate boundary. Large and moderate shallow earthquakes with Mw ≥ 6 occurred on E-W to NE-SW active thrust-related-fold structures an among them the 21 May 2003 Zemmouri earthquake (Mw 6.8) that caused 0.5 m uplift on 55 km coastal. In this work, we study the correlation between the 2003 coseismic uplift with the long-term active deformation using the distribution of Quaternary marine and alluvial terraces where indicators show three pre-2003 main notch levels formed in the last 21.9 ka along with five alluvial terrace levels formed in Pleistocene. The analysis of drainage system and related tectonic geomorphology along the coastal area show over 500 small and large rivers that document the trend of present-day and past stream channels, their longitudinal profiles, the arrangement of Quaternary deposits and the response of river mouths to the successive past and recent uplift. The analysis of remote sensing images combined with high-resolution Digital Elevation Model and field observations reveal concave downward shape of most river profiles and river mouth deflections near the coastline. Data previously obtained on the coseismic deformation using coastal tectonics, seismology and geodetic (InSAR and GPS) investigations are combined to our analysis of coastal deformation. The results confirm the impact of the offshore thrust fault responsible of the coastal deformation through successive coseismic uplift with an estimated average 0.9 to 2.1 mm/year during the late Pleistocene - Holocene (Maouche et al.,2011). The short-term and long-term deformation and related surface slip distribution controls the drainage system and related distribution of Quaternary deposits. Our results indicate how the tectonic geomorphology can be a decisive marker for the identification of coastal active faults and

  5. Phenocrysts and megacrysts of olivines from ultramafic lamprophyres of the Chadobets and Il'bokich uplifts, Southwestern Siberia (United States)

    Smirnova, Maria; Sazonova, Lyudmila; Nosova, Anna; Kargin, Alexey; Shcherbakov, Vasiliy


    The study of composition and zoning of olivines from ultramafic lamprophyres of the SW Siberian craton allowed us to distinguish their main types (phenocrysts and megacrysts) and to estimate the possible P-T conditions of phenocryst crystallization. The studied rocks occur as sills and dikes in the Chadobets and Il'bokich uplifts of the Irkeneeva-Chadobets trough. The ultramafic lamprophyres of these uplifts are spaced around 80 km apart and differ in age by more than 150 Ma. The rocks of the Il'bokich Uplift are dated at Devonian, while the age of the Chadobets Complex is restricted to the Triassic. The episodes of these complexes formation were separated by the large flood basalt event. According to classification (Tappe et al., 2005), the studied rocks are aillikite and damtjernite. Olivine phenocrysts from the rocks of the Il'bokich and Chadobets complexes are represented by sub- and euhedral grains. They are composed of core, transitional zone, and rim. Olivine cores in the aillikites of the Il'bokich Complex are characterized by Mg# 89; CaO - 0.13-0.14 wt %; TiO2 around 0.03 wt %, Al - 200-380 ppm, and Cr - 130-340 ppm. The cores of phenocrysts from the Chadobets lamprophyres have Mg# 85-87, CaO varying within 0.1-0.2 wt %, and TiO2 - 0.02-0.05 wt %. The megacrysts differ from the phenocrysts of these rocks in the lower Mg# 83-84 and CaO - 0.08-0.14 wt % at higher TiO2 - 0.04-0.05 wt %. Al - 100-700 ppm, Cr - 20-65 ppm. The most striking difference between olivines of the two complexes is observed between their Mg#-Ni relations. The cores of olivine phenocrysts from the Il'bokich lamprophyres are characterized by the high Mg number (Mg# = 89) and Ni content (2800-3000 ppm), whereas olivine cores of the Chadobets aillikites have higher contents of Ni (3000-3500 ppm) at lowered (Mg# = 86-88). These characteristics reflect the compositions of their protolith. The temperature was estimated using monomineral olivine thermometer based on the contents of Cr and Al

  6. Thermodynamic model for uplift and deflation episodes (bradyseism) associated with magmatic-hydrothermal activity at the Campi Flegrei (Italy) (United States)

    Lima, Annamaria; De Vivo, Benedetto; Spera, Fran J.; Bodnar, Robert J.; Milia, Alfonsa; Nunziata, Concettina; Belkin, Harvey E.; Cannatelli, Claudia


    Campi Flegrei (CF) is a large volcanic complex located west of the city of Naples, Italy. Repeated episodes of bradyseism (slow vertical ground movement) near the town of Pozzuoli have been documented since Roman times. Bradyseismic events are interpreted as the consequence of aqueous fluid exsolution during magma solidification on a slow timescale (103–104 yr) superimposed upon a shorter (1–10 yr) timescale for the episodic expulsion of fluid from a deep (~ 3–5 km) lithostatically-pressured low-permeability reservoir to an overlying hydrostatic reservoir. Cycles of inflation and deflation occur during short duration transient events when connectivity is established between deep and shallow hydrothermal reservoirs. The total seismic energy released (4 × 1013 J) during the 1983–1984 bradyseismic crisis is consistent with the observed volume change (uplift) and consistent with the notion that seismic failure occurs in response to the shear stress release induced by volume change. Fluid transport and concomitant propagation of hydrofractures as fluid expands from lithostatic to hydrostatic pressure during decompression leads to ground surface displacement. Fluid decompression occurs along the fluid isenthalp (Joule–Thompson expansion) during transient periods of reservoir connectivity and leads to mineral precipitation. Each kilogram of fluid precipitates about 3 × 10− 3 kg of silica along a typical decompression path along the isenthalp. Mineral precipitation modifies the permeability and acts to reseal connection paths thereby isolating lithostatic and hydrostatic reservoirs ending one bradyseism phase and beginning another. Crystallization and exsolution of the magmatic fluid generates ≈ 7 × 1015 J of mechanical (PΔV) energy, and this is sufficient to accomplish the observed uplift at CF. Although magma emplacement is the ultimate origin of bradyseism, fresh recharge of magma is not a prerequisite. Instead, short to intermediate

  7. Rapid ice unloading in the Fleming Glacier region, southern Antarctic Peninsula, and its effect on bedrock uplift rates (United States)

    Zhao, Chen; King, Matt A.; Watson, Christopher S.; Barletta, Valentina R.; Bordoni, Andrea; Dell, Matthew; Whitehouse, Pippa L.


    Rapid regional warming in the Antarctic Peninsula has led to the significant retreat and eventual collapse of several major ice shelves since the 1970s, triggering the subsequent acceleration and thinning of their feeding glaciers. The Wordie Ice Shelf, lying off the west coast of the Antarctic Peninsula, has undergone long-term disintegration since the 1960s with a substantial calving event occurring around 1989, followed by continuous steady retreat and its almost-complete disappearance. The dynamic response of the upstream glaciers to the ice shelf collapse and the response of the solid Earth to the associated mass loss are not fully understood. To quantify the mass loss from the system, we generated a digital elevation model (DEM) using airborne vertical and oblique imagery from 1966 and compared it to a DEM derived from 2008 SPOT data. This analysis reveals lowering over that time of approximately 60 m at the front of Fleming Glacier. Using IceBridge and ICESat-2/GLAS data spanning 2002-2014, we show an increased rate of mean ice-surface lowering, with rates post-2008 more than twice those of 2002-2008. We use these load change data as a basis for the simulation of viscoelastic solid Earth deformation. We subtract modeled elastic deformation rates, and a suite of modeled viscous rates, from GPS-derived three-dimensional bedrock velocities at sites to the south of Fleming Glacier to infer properties of Earth rheology. Assuming the pre-breakup bedrock uplift was positive due to post-Last Glacial Maximum (LGM) ice retreat, our viscoelastic-corrected GPS uplift rates suggest upper mantle viscosities are > 2 ×1019 Pas and likely > 1 ×1020 Pas in this region, 1-2 orders of magnitude greater than previously found for the northern Antarctic Peninsula. Horizontal velocities at the GPS site nearest the Fleming Glacier, after the application of elastic and plate tectonic corrections, point away from Marguerite Bay rather than the present glacier front. This suggests

  8. Distribution and erosion of the Paleozoic tectonic unconformities in the Tarim Basin, Northwest China: Significance for the evolution of paleo-uplifts and tectonic geography during deformation (United States)

    Lin, Changsong; Yang, Haijun; Liu, Jingyan; Rui, Zhifeng; Cai, Zhenzhong; Zhu, Yongfeng


    The distribution and erosional features of the Paleozoic major tectonic unconformities in the Tarim Basin, and their genetic relation to the development of paleo-uplifts as well as the evolution of geodynamic settings, are documented in this paper based on the integral analysis of seismic, drilling, and outcrop data. During the Paleozoic, the Tarim Basin underwent three major tectonic deformation stages, which resulted in three angular unconformities and in significant changes in basin geomorphology and paleogeography. The tectonic deformation at the end of the Middle Ordovician was characterized by development of the southern central paleo-uplift, the northern depression, and the southeastern Tangguzibasi depression in the basin. The thickest denudation belts of the unconformity (Tg5-2) are distributed mainly along the thrust structural highs. A stronger deformation event took place at the end of the Late Ordovician and formed a huge uplift along the southwestern and southeastern basin margins and the western part of the Tabei uplift along the northern basin margin, producing an extensive angular unconformity (Tg5) with maximum erosion thickness of 1500-2000 m. This tectonic event resulted in an abrupt change in overall geography of the basin, from a deepwater marine environment at the late stages of the Late Ordovician to a littoral and neritic basin in the Early Silurian. The deformation that occurred at the end of the Middle Devonian was the strongest in the Paleozoic. It generated the most widespread angular unconformity (Tg3) within the basin and led to extensive erosion, with maximum denudation thickness of 3000-5000 m in the northern and northeastern parts of the basin. The topography of the basin during the late Devonian was characterized by a high in the northeast and a low in the southwest, forming an embayment basin opening to the southwest during the Early Devonian to Carboniferous. The transgression in general from southwest to northeast deposited

  9. Constraining the timing of Shillong Plateau uplift from a study of the palaeo-Brahmaputra deposits, Siwalik Group, Samdrup Jongkhar, Eastern Bhutan (United States)

    Govin, G.; Najman, Y.; Grujic, D.; Van Der Beek, P.; Davenport, J.; Huyghe, P.


    The ~400 km long and two km high Shillong Plateau is the only major raised topography in the Himalayan foreland. Debates over the timing of uplift and implication for erosion-climate-tectonic couplings, strain partitioning within the Himalaya and the palaeodrainage history of the palaeo-Brahmaputra are important. Grujic et al, (2006) proposed that the uplift of the plateau has affected the exhumation of Himalayan rocks to the north in Bhutan, due to the creation of a regional climatic change in the plateau's rain shadow. By contrast, Coutand et al. (2014) suggest that the local decrease in erosion rates in the eastern Bhutan Himalaya is best explained by the decrease in overthrusting rates at 5-6 Ma, which might be potentially related to late Miocene to Pliocene changes in the India-southern Eurasia convergence partitioning, with shortening taken up by faults bounding the Shillong Plateau, i.e. by its uplift. The exhumation of the Shillong Plateau has been proposed to initiate by 8-15 Ma (Biswas et al, 2007; Clark & Bilham, 2008) whilst surface uplift, decoupled from exhumation, of Miocene (Chirouze et al 2013), Pliocene (Johnson and Nur Alam 1991; Biswas et al., 2007) and Early Quaternary (Najman et al, in review) have been proposed. Our study uses the foreland basin Siwalik sedimentary record preserved to the north of the Shillong Plateau in Bhutan, to constrain the plateau's uplift history. Provenance is characterized by U-Pb dating on detrital zircons, which allows specifically documenting an Indus-Yarlung suture-zone and therefore paleo-Brahmaputra signature. We document the timing that the palaeo-Brahmaputra was shunted north and west by the rising plateau, using this U/Pb provenance technique to detect first appearance of the river and to a minor degree the Namche Barwa syntaxe signature. The results allow to better constrain the period of uplifting of the Shillong Plateau and thus better inform the implications through a study of the palaeodrainage of the

  10. Coupling erosion and topographic development in the rainiest place on Earth: Reconstructing the Shillong Plateau uplift history with in-situ cosmogenic 10Be (United States)

    Rosenkranz, Ruben; Schildgen, Taylor; Wittmann, Hella; Spiegel, Cornelia


    The uplift of the Shillong Plateau, in northeast India between the Bengal floodplain and the Himalaya Mountains, has had a significant impact on regional precipitation patterns, strain partitioning, and the path of the Brahmaputra River. Today, the plateau receives the highest measured yearly rainfall in the world and is tectonically active, having hosted one of the strongest intra-plate earthquakes ever recorded. Despite the unique tectonic and climatic setting of this prominent landscape feature, its exhumation and surface uplift history are poorly constrained. We collected 14 detrital river sand and 3 bedrock samples from the southern margin of the Shillong Plateau to measure erosion rates using the terrestrial cosmogenic nuclide 10Be. The calculated bedrock erosion rates range from 2.0 to 5.6 m My-1, whereas catchment average erosion rates from detrital river sands range from 48 to 214 m My-1. These rates are surprisingly low in the context of steep, tectonically active slopes and extreme rainfall. Moreover, the highest among these rates, which occur on the low-relief plateau surface, appear to have been affected by anthropogenic land-use change. To determine the onset of surface uplift, we coupled the catchment averaged erosion rates with topographic analyses of the plateau's southern margin. We interpolated an inclined, pre-incision surface from minimally eroded remnants along the valley interfluves and calculated the eroded volume of the valleys carved beneath the surface. The missing volume was then divided by the volume flux derived from the erosion rates to obtain the onset of uplift. The results of this calculation, ranging from 3.0 to 5.0 Ma for individual valleys, are in agreement with several lines of stratigraphic evidence from the Brahmaputra and Bengal basin that constrain the onset of topographic uplift, specifically the onset of flexural loading and the transgression from deltaic to marine deposition. Ultimately, our data corroborate the

  11. InSAR Time Series Analysis and Geophysical Modeling of City Uplift Associated with Geothermal Drillings in Staufen im Breisgau, Germany (United States)

    Motagh, M.; Lubitz, C.


    Geothermal energy is of increasing importance as alternative, environmentally friendly technology for heat management. Direct interaction with the subsurface requires careful implementation, in particular in geological complex regions. The historical city Staufen im Breisgau, SW Germany, has attracted national attention as a case of implementation failure with severe consequences, causing debates on the applicability and security of this sustainable technique. Located at the eastern transition zone of the Upper Rhine Graben and the Schwarzwald massif, the geothermal potential is high at Staufen due to strong temperature gradients. In September 2007, seven boreholes for geothermal probes were drilled up to a depth of 140 m to provide a new heat management for the city hall. Within five years an uplift phenomenon has been observed in Staufen reaching more than 40 cm in places and 269 buildings were damaged. Hydro-chemical driven anhydrite-gypsum transformation in the subsurface was identified as the cause leading to volume increase that is observable as surface uplift. This process is associated with the geothermal drilling activities that have crossed several groundwater levels. In this work, we summarize and present the findings of spaceborne Synthetic Aperture Radar Interferometry (InSAR) analysis of the uplift in Staufen over the last five years from July 2008 through July 2013. By applying the Small Baseline Subset (SBAS) method, we find a localized elliptical-shaped deformation field in NE-SW orientation. Area of maximum uplift is located 50 m NNE of the drilling zone. At this location, we observe a cumulative uplift of approx. 13.7 cm ± 0.34 cm (mean value within an area of 30 m by 30 m) from July 2008 to July 2009, which reduced to cumulative uplift of 3 cm ± 0.25 cm from July 2012 to July 2013. The deceleration can be related to applied countermeasures as borehole sealing and groundwater pumping. The observed ground surface response was compared to

  12. Munroa argentina, a Grass of the South American Transition Zone, Survived the Andean Uplift, Aridification and Glaciations of the Quaternary (United States)

    Amarilla, Leonardo D.; Anton, Ana M.; Chiapella, Jorge O.; Manifesto, María M.; Angulo, Diego F.; Sosa, Victoria


    The South American Transition Zone (SATZ) is a biogeographic area in which not only orogeny (Andes uplift) and climate events (aridification) since the mid-Miocene, but also Quaternary glaciation cycles had an important impact on the evolutionary history of the local flora. To study this effect, we selected Munroa argentina, an annual grass distributed in the biogeographic provinces of Puna, Prepuna and Monte. We collected 152 individuals from 20 localities throughout the species’ range, ran genetic and demographic analyses, and applied ecological niche modeling. Phylogenetic and population genetic analyses based on cpDNA and AFLP data identified three phylogroups that correspond to the previously identified subregions within the SATZ. Molecular dating suggests that M. argentina has inhabited the SATZ since approximately 3.4 (4.2–1.2) Ma and paleomodels predict suitable climate in these areas during the Interglacial period and the Last Glacial Maximum. We conclude that the current distribution of M. argentina resulted from the fragmentation of its once continuous range and that climate oscillations promoted ecological differences that favored isolation by creating habitat discontinuity. PMID:26110533

  13. The carbon-isotopic composition of Proterozoic carbonates: Riphean successions from northwestern Siberia (Anabar Massif, Turukhansk Uplift) (United States)

    Knoll, A. H.; Kaufman, A. J.; Semikhatov, M. A.


    Thick carbonate-dominated successions in northwestern Siberia document secular variations in the C-isotopic composition of seawater through Mesoproterozoic and early Neoproterozoic (Early to early Late Riphean) time. Mesoproterozoic dolomites of the Billyakh Group, Anabar Massif, have delta 13C values that fall between 0 and -1.9 permil versus PDB, with values in the upper part of the succession (Yusmastakh Formation) consistently higher than those of the lower (Ust'-Il'ya and Kotuikan formations). Consistent with available biostratigraphic and radiometric data, delta 13C values for Billyakh carbonates compare closely with those characterizing early Mesoproterozoic carbonates (about 1600-1200 Ma) worldwide. In contrast, late Mesoproterozoic to early Neoproterozoic limestones and dolomites in the Turukhansk Uplift exhibit moderate levels of secular variation. Only the lowermost carbonates in the Turukhansk succession (Linok Formation) have delta 13C values that approximate Billyakh values. Higher in the Turukhansk succession, delta 13C values vary from -2.7 to +4.6 permil (with outliers as low as -5.0 permil interpreted as diagentically altered). Again, consistent with paleontological and radiometric data, these values compare well with isotopic values from 1200 to 850 Ma successions elsewhere. Five sections measured in different parts of the Turukhansk basin show nearly identical patterns of variation, confirming that carbonate delta 13C correlates primarily with time and not facies. The Siberian sections illustrate the potential of integrated biostratigraphic and chemostratigraphic data in the intra- and interbasinal correlation of Mesoproterozoic and early Neoproterozoic rocks.

  14. Mantle Subduction and Uplift of Intracontinental Mountains: A Case Study from the Chinese Tianshan Mountains within Eurasia. (United States)

    Li, Jinyi; Zhang, Jin; Zhao, Xixi; Jiang, Mei; Li, Yaping; Zhu, Zhixin; Feng, Qianwen; Wang, Lijia; Sun, Guihua; Liu, Jianfeng; Yang, Tiannan


    The driving mechanism that is responsible for the uplift of intracontinental mountains has puzzled geologists for decades. This study addresses this issue by using receiver function images across the Chinese Tianshan Mountains and available data from both deep seismic profiles and surface structural deformation. The near-surface structural deformation shows that the Tianshan crust experienced strong shortening during the Cenozoic. The receiver function image across the Tianshan Mountains reveals that the lithosphere of the Junggar Basin to the north became uncoupled along the Moho, and the mantle below the Moho subducted southwards beneath the northern part of the Tianshan Mountains, thereby thickening the overlying crust. Similar deep structures, however, are not observed under the Tarim Basin and the adjacent southern Tianshan Mountains. This difference in the deep structures correlates with geomorphological features in the region. Thus, a new model of mantle subduction, herein termed M-type subduction, is proposed for the mountain-building processes in intracontinental compressional settings. The available geomorphological, geological and seismic data in the literatures show that this model is probably suitable for other high, linear mountains within the continent.

  15. Evolutionary response to the Qinghai-Tibetan Plateau uplift: phylogeny and biogeography of Ammopiptanthus and tribe Thermopsideae (Fabaceae

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    Wei Shi


    Full Text Available Previous works resolved diverse phylogenetic positions for genera of the Fabaceae tribe Thermopsideae, without a thoroughly biogeography study. Based on sequence data from nuclear ITS and four cpDNA regions (matK, rbcL, trnH-psbA, trnL-trnF mainly sourced from GenBank, the phylogeny of tribe Thermopsideae was inferred. Our analyses support the genera of Thermopsideae, with the exclusion of Pickeringia, being merged into a monophyletic Sophoreae. Genera of Sophoreae were assigned into the Thermopsoid clade and Sophoroid clade. Monophyly of Anagyris, Baptisia and Piptanthus were supported in the Thermopsoid clade. However, the genera Thermopsis and Sophora were resolved to be polyphyly, which require comprehensive taxonomic revisions. Interestingly, Ammopiptanthus, consisting of A. mongolicus and A. nanus, nested within the Sophoroid clade, with Salweenia as its sister. Ammopiptanthus and Salweenia have a disjunct distribution in the deserts of northwestern China and the Hengduan Mountains, respectively. Divergence age was estimated based on the ITS phylogenetic analysis. Emergence of the common ancestor of Ammopiptanthus and Salweenia, divergence between these two genera and the split of Ammopiptanthus species occurred at approximately 26.96 Ma, 4.74 Ma and 2.04 Ma, respectively, which may be in response to the second, third and fourth main uplifts of the Qinghai-Tibetan Plateau, respectively.

  16. Development of the reed bed in Matsalu wetland, Estonia: responses to neotectonic land uplift, sea level changes and human influences

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    Mats Meriste


    Full Text Available We studied reed bed development in Matsalu wetland and the Kasari River delta, Estonia, since the late 18th century using historical schemes, topographical maps and aerial photographs. Our aim was to understand the mechanisms controlling reed distribution in Matsalu wetland, the largest coastal wetland of the eastern Baltic Sea occupying an area of about 25 km2. Natural development of the reed bed in Matsalu Bay and the Kasari delta is mainly controlled by shoreline displacement due to post-glacial neotectonic land uplift. The dredging of the Kasari delta in the 1920s–1930s caused a rapid seaward migration of reed bed communities due to the dispersal of fragmented rhizomes on the shallow sea bottom and along the canal banks reaching Matsalu Bay, while the landward parts of the former wetland were occupied by meadow communities. The expansion of the reed bed started in between the 1951s and 1970s and a maximum extent of 27 km2 was gained by the late 1970s at the peak of eutrophication. In the last decades the reed bed development has been influenced by sea level rise and increased intensity of cyclonic activity in the Baltic Sea, which has caused the deterioration of the reed bed that was weakened by eutrophication due to nutrient inflow from agricultural landscapes mainly in the 1960s–1980s.

  17. Genesis of the Ordovician fluorite and its geological significance in central uplift of the Tarim basin, China (United States)

    Wang, Zhenyu; Zhang, Yunfeng; Tao, Xiayan; Zhu, Bo; Luo, Chunshu


    Based on analysis of karst fractured-vuggy filling mineralogy and geochemical fluorite in the Hercynian, further research was carried out regarding the formation and significance of fluorite in the Central Uplift of the Tarim Basin. The Hercynian fractured-vuggy and filling succession of fracture-cave minerals were developed under a mixed background of low-temperature magmatic hydrothermal fluid and upper strata brine. An overlapping and associating relationship exists between the generation of fluorite and the buried dissolution or oil and gas migration. The fluorite volume decreased by 26.4 % after the calcite had been metasomatized by fluorite, resulting in plentiful intergranular spaces, which formed an appreciable reservoir space. At the same time, the hydrothermal fluid carried by fluorite eroded adjacent rock through fractures or fissures, forming an irregular fracture-cave system, accompanied by hydrocarbon migration. The hydrocarbon migration and accumulation occurring in the Late Hercynian-Indosinian are closely related to the sedimentation of fluorite and several hydrothermal minerals.

  18. Restoration of the Cretaceous uplift of the Harz Mountains, North Germany: Evidence for thick-skinned thrusting (United States)

    Tanner, David C.; Krawczyk, Charlotte M.


    Fault prediction and kinematic restoration are useful tools to firstly determine the likely geometry of a fault at depth and secondly restore the pre-deformation state to discover, for instance, paleogeometry. The inclined-shear method with constant slip uses the known geometry of the surface position and dip of the fault and the geometries of the hanging and footwall beds to predict the probable shape of the fault at depth, down to a detachment level. We use this method to determine the geometry of the Northern Harz Boundary Fault in northern Germany that was responsible for the uplift of the Harz Mountains during Late Cretaceous inversion. A shear angle of 30° was most likely in this case, as indicated by geological and geophysical data. This suggests that the detachment level is at a depth of ca. 25 km. Kinematic restoration of the Harz Mountains using this fault geometry does not produce a flat horizon, rather it results in a 3.5 km depression. Restoration also causes a rotation of fabrics within the Harz Mountains of approximately 11° clockwise. Airy-Heiskanen isostatic equilibrium adjustment reduces the depression to ca. 1 km depth, as well as raising the Moho from 41 to 36 km depth. We show that this model geometry is also a very good fit to the interpreted DEKORP BASIN 9601 deep seismic profile.

  19. Steady incision of Grand Canyon at the million year timeframe: A case for mantle-driven differential uplift (United States)

    Crow, Ryan; Karlstrom, Karl; Darling, Andrew; Crossey, Laura; Polyak, Victor; Granger, Darryl; Asmerom, Yemane; Schmandt, Brandon


    The Grand Canyon region provides an excellent laboratory to examine the interplay between river incision, magmatism, and the geomorphic and tectonic processes that shape landscapes. Here we apply U-series, Ar-Ar, and cosmogenic burial dating of river terraces to examine spatial variations in incision rates along the 445 km length of the Colorado River through Grand Canyon. We also analyze strath terrace sequences that extend to heights of several hundred meters above the river, and integrate these with speleothem constrained maximum incision rates in several reaches to examine any temporal incision variations at the million-year time frame. This new high-resolution geochronology shows temporally steady long-term incision in any given reach of Grand Canyon but significant variations along its length from 160 m/Ma in the east to 101 m/Ma in the west. Spatial and temporal patterns of incision, and the long timescale of steady incision rule out models where geomorphic controls such as climate oscillations, bedrock strength, sediment load effects, or isostatic response to differential denudation are the first order drivers of canyon incision. The incision pattern is best explained by a model of Neogene and ongoing epeirogenic uplift due to an eastward propagating zone of increased upper mantle buoyancy that we infer from propagation of Neogene basaltic volcanism and a strong lateral gradient in modern upper mantle seismic structure.

  20. Uplift of Kelud Volcano Prior to the November 2007 Eruption as Observed by L-Band Insar

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    Ashar Muda Lubis


    Full Text Available Kelud volcano, a stratovolcano with summit elevation of 1731 m above sea level, is considered to be one of the most dangerous volcanoes in Java, Indonesia. Kelud volcano erupts frequently, with the most recent eruption occurred on November 3, 2007. Therefore, volcano monitoring, especially detecting precursory signals prior to an eruption, is important for hazard mitigation for Kelud volcano. Interferometric Synthetic Aperture Radar (InSAR has been proven to bea powerful tool for investigating earth-surface deformation. Hence, we applied D-InSAR (differential InSAR in an effort to identify pre-eruptive deformation of Kelud volcano before November 2007 eruption. SAR images, L band ALOS-PALSAR, were used to construct 3 coherent interferograms between January to May 2007. We used the D-InSAR technique to remove topographic effects from interferometry images. During the interval observation, we detected a continuous inflation with a maximum line-of-sight (LOS displacement of 11cm. Uplift of Kelud volcano was also observed by the tiltmeter 1-2 months prior to the November 2007 eruption. We interpret this inflation as a manifestation of increased volume of magmatic material in the shallow reservoir and magmatic migration towards the surface, indicating an imminent eruption. This study confirms that InSAR technique is a valuable tool for monitoring volcano towards better hazard mitigations.

  1. U-Pb ages of detrital zircons from deep-water Well LS33A at Lingnan Low Uplift of the Qiongdongnan Basin and their geological significances (United States)

    Xiu, C.; Sun, Z. P.; Zhai, S. K.; Liu, X. Y.; Liu, X. F.; Chen, K.


    U-Pb ages of detrital zircons from Well LS33A at Lingnan Low Uplift of the Qiongdongnan Basin (QDNB) are measured with LA-ICP-MS technique. Th/U ratios of detrital zircons mostly with oscillatory zoning are higher than 0.1, indicating a magmatic origin. Zircon U-Pb data of the Yacheng Formation yield an age range from 95.8 to 387.9 Ma, with two major clusters of 95-106 Ma and 214-237 Ma, representing Yanshanian and Indosinian, respectively. U-Pb age range of the Yinggehai-Ledong Formations varies widely from 87 to 2 490 Ma, exhibiting four remarkable age peaks of 88 Ma, 146 Ma, 208 Ma and 386 Ma on age spectrum. The variation in zircon age assemblage reveals that in provenance. Based on synthesizing seismic data, heavy mineral assemblages, geochemical data and zircon U-Pb ages, the main conclusions are as follows. There existed frequent fault-block activities in study area during the Yacheng deposition of Early Oligocene, which controlled the wedge-shaped disorderly fillings, and sediments chiefly came from the southern exposed tectonic uplift area of the QDNB. As it entered post-rifting stage and transgression continued, the provenance from the Pliocene to the Quaternary expanded to far- and multi-source realm, with Hainan Island, Red River and Indo-China Peninsula being source areas. The Proterozoic metamorphic basement, which supplied main material sources for the Yacheng Formation of Well LS33A, existed in the southern tectonic uplift area. Two large-scale magmatic activities, occurring in the southern uplift area in the Indosinian (214-237 Ma) and Yanshanian (95-106 Ma), not only destroyed the original metamorphic basement, but also provided an acidic magmatic provenance to study area.

  2. Tilting of Lake Pielinen, eastern Finland – an example of extreme transgressions and regressions caused by differential post-glacial isostatic uplift


    Heikki Seppä; Matti Tikkanen; Jari-Pekka Mäkiaho


    Tilting of large lakes due to differential isostatic uplift in the glaciated regions of the Northern Hemisphere is a well-documented process. With the help of accurate digital elevation models and spatial GIS analysis techniques, the resulting hydro­logical changes, including shifts in the outlets and changes in the size and configuration of lakes, can now be mapped and calculated more precisely than before. As a case study to highlight the magnitude of such changes in Fennoscandia, we invest...

  3. On the potential asthenospheric linkage between Apenninic slab rollback and Alpine topographic uplift: insights from P wave tomography and seismic anisotropy analysis (United States)

    Malusa', Marco Giovanni; Salimbeni, Simone; Zhao, Liang; Guillot, Stéphane; Pondrelli, Silvia; Margheriti, Lucia; Paul, Anne; Solarino, Stefano; Aubert, Coralie; Dumont, Thierry; Schwartz, Stéphane; Wang, Qingchen; Xu, Xiaobing; Zheng, Tianyu; Zhu, Rixiang


    The role of surface and deep-seated processes in controlling the topography of complex plate-boundary areas is a highly debated issue. In the Western Alps, which include the highest summits in Europe, factors controlling topographic uplift still remain poorly understood. In the absence of active convergence, recent works have suggested a potential linkage between slab breakoff and fast uplift, but this hypothesis is ruled out by the down-dip continuity of the Alpine slab documented by recent tomographic images of the upper mantle beneath the Alpine region (Zhao et al. 2016). In order to shed light on this issue, we use a densely spaced array of temporary broadband seismic stations and previously published observations to analyze the seismic anisotropy pattern along the transition zone between the Alps and the Apennines, within the framework of the upper mantle structure unveiled by P wave tomography. Our results show a continuous trend of anisotropy fast axes near-parallel to the western alpine arc, possibly due to an asthenospheric counterflow triggered by the eastward retreat of the Apenninic slab. This trend is located in correspondence of a low velocity anomaly in the European upper mantle, and beneath the Western Alps region characterized by the highest uplift rates, which may suggest a potential impact of mantle dynamics on Alpine topography. We propose that the progressive rollback of the Apenninic slab induced a suction effect and an asthenospheric counterflow at the rear of the unbroken Alpine slab and around its southern tip, as well as an asthenospheric upwelling, mirrored by low P wave velocities, which may have favored the topographic uplift of the Alpine belt from the Mt Blanc to the Ligurian coast. Zhao L. et al., 2016. Continuity of the Alpine slab unraveled by high-resolution P wave tomography. J. Geophys. Res., doi:10.1002/2016JB013310.

  4. Inverse modeling of ground surface uplift and pressure with iTOUGH-PEST and TOUGH-FLAC: The case of CO2 injection at In Salah, Algeria (United States)

    Rinaldi, Antonio P.; Rutqvist, Jonny; Finsterle, Stefan; Liu, Hui-Hai


    Ground deformation, commonly observed in storage projects, carries useful information about processes occurring in the injection formation. The Krechba gas field at In Salah (Algeria) is one of the best-known sites for studying ground surface deformation during geological carbon storage. At this first industrial-scale on-shore CO2 demonstration project, satellite-based ground-deformation monitoring data of high quality are available and used to study the large-scale hydrological and geomechanical response of the system to injection. In this work, we carry out coupled fluid flow and geomechanical simulations to understand the uplift at three different CO2 injection wells (KB-501, KB-502, KB-503). Previous numerical studies focused on the KB-502 injection well, where a double-lobe uplift pattern has been observed in the ground-deformation data. The observed uplift patterns at KB-501 and KB-503 have single-lobe patterns, but they can also indicate a deep fracture zone mechanical response to the injection. The current study improves the previous modeling approach by introducing an injection reservoir and a fracture zone, both responding to a Mohr-Coulomb failure criterion. In addition, we model a stress-dependent permeability and bulk modulus, according to a dual continuum model. Mechanical and hydraulic properties are determined through inverse modeling by matching the simulated spatial and temporal evolution of uplift to InSAR observations as well as by matching simulated and measured pressures. The numerical simulations are in agreement with both spatial and temporal observations. The estimated values for the parameterized mechanical and hydraulic properties are in good agreement with previous numerical results. In addition, the formal joint inversion of hydrogeological and geomechanical data provides measures of the estimation uncertainty.

  5. The last interglacial period at Guantanamo Bay, Cuba and an estimate of late Quaternary tectonic uplift rate in a strike-slip regime (United States)

    Schweig, E. S.; Muhs, D. R.; Simmons, K. R.; Halley, R. B.


    Guantanamo Bay, Cuba is an area dominated by a strike-slip tectonic regime and is therefore expected to have very low Quaternary uplift rates. We tested this hypothesis by study of an unusually well preserved emergent reef terrace around the bay. Up to 12 m of unaltered, growth-position reef corals are exposed at about 40 sections examined around ˜40 km of coastline. Maximum reef elevations in the protected, inner part of the bay are ˜11-12 m, whereas outer-coast shoreline angles of wave-cut benches are as high as ˜14 m. Fifty uranium-series analyses of unrecrystallized corals from six localities yield ages ranging from ˜134 ka to ˜115 ka, when adjusted for small biases due to slightly elevated initial 234U/238U values. Thus, ages of corals correlate this reef to the peak of the last interglacial period, marine isotope stage (MIS) 5.5. Previously, we dated the Key Largo Limestone to the same high-sea stand in the tectonically stable Florida Keys. Estimates of paleo-sea level during MIS 5.5 in the Florida Keys are ~6.6 to 8.3 m above present. Assuming a similar paleo-sea level in Cuba, this yields a long-term tectonic uplift rate of 0.04-0.06 m/ka over the past ~120 ka. This estimate supports the hypothesis that the tectonic uplift rate should be low in this strike-slip regime. Nevertheless, on the southeast coast of Cuba, east of our study area, we have observed flights of multiple marine terraces, suggesting either (1) a higher uplift rate or (2) an unusually well-preserved record of pre-MIS 5.5 terraces not observed at Guantanamo Bay.

  6. Diapiric uplift of an MIS 3 marine deposit in SW Spain: Implications for Late Pleistocene sea level reconstruction and palaeogeography of the Strait of Gibraltar (United States)

    Gracia, F. J.; Rodríguez-Vidal, J.; Cáceres, L. M.; Belluomini, G.; Benavente, J.; Alonso, C.


    In the Bay of Cádiz (SW Spain) an Upper Pleistocene beach deposit (31.5 ka BP) has been recognised at about 1-3 m above m.s.l. The deposit is affected by a set of joints and fractures filled by calcretes and other subaerial sediments, dated at 19.9 ka BP. Deformation and uplift of this level is related to the moderate activity of a diapiric structure. The resulting uplift produced local emersion of the deposit and a transition from marine to continental conditions during the Late Quaternary. The deformational style and tectonic location of the deposit argue against strong vertical motion. Regional comparisons between this diapir and other similar and coeval structures near the zone suggest a vertical uplift of about 25 m. Therefore, between 30 and 20 ka BP the sea level can be supposed to have been placed near to its present-day position, probably less than 30 m below. These results confirm other regional data indicating that during MIS 3 several relative sea level rises took place, reaching heights of only several tens of metres below the present m.s.l. The palaeogeographical implications of these results include the existing controversy about the possible crossing of the Strait of Gibraltar by Neanderthals between ca 40 and 30 ka. The palaeogeographical reconstruction of the Strait for this period suggests that its width and depth were very similar to the present ones.

  7. Source facies of the Paleozoic petroleum systems in the Tabei uplift, Tarim Basin, NW China: implications from aryl isoprenoids in crude oils

    Energy Technology Data Exchange (ETDEWEB)

    Yongge Sun; Shiping Xu; Hong Lu; Pingxia Cuai [Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou (China). SKLOG


    Aryl isoprenoids have been detected for the first time in crude oils from Paleozoic petroleum systems in the Tabei uplift, Tarim Basin, northwestern China. The principal compounds possess the 1-alkyl-2,3,6-trimethyl substitution pattern characteristic of diaromatic carotenoids found in the Chlorobiaceae family of photosynthetic sulfur bacteria, with a predominance of C{sub 13} - C{sub 23} homologues in these samples. Flash pyrolysates of the asphaltene fractions isolated from crude oils show an unusual abundance of 1,2,3,4-tetramethylbenzene, an indicator for a significant contribution of diaromatic carotenoids to the source kerogen of these oils. The wide distribution of these compounds in crude oils reveals that penetration of the photic zone by sulfidic waters during deposition enabled prolific growth of photosynthetic green sulphur bacteria (Chlorobiaceae). This suggests that the source rocks for the Paleozoic petroleum systems in the Tabei uplift were likely deposited under euxinic conditions with sulfate and sulfide-rich water bodies, which doesn't support previously published conclusions of a Middle-Upper Ordovician source that marks the slope facies at the margins of structural uplifts. (author)

  8. Sediment accumulation history in the Mozambique passive margin basin and kinematics of the South African Plateau uplift during Meso-Cenozoic time (United States)

    Said, Aymen; Moder, Christoph; Clark, Stuart; Skogseid, Jakob


    The kinematic history of the South African (Kalahari) Plateau uplift during Meso-Cenozoic time is not well understood. Quantifying the terrigeneous sediment budget in its surrounding passive margin basins using a source to sink approach helps to figure out the evolution of this continental relief. In this study, we use data from 43 wells drilled in the Mozambique passive margin basin to estimate the volume of sediments preserved for each time interval, and corrected for in situ production and for remaining porosity. Results show two periods of high accumulation rates. The first is recorded during Mid-Late Cretaceous and is well described in similar studies in the Namibia and South Africa margins, which supports a major uplift of the whole Kalahari Plateau in the Mid-Late Cretaceous. The second high accumulation rate is recorded during the Miocene and is consistent with a relief reorganization driven by uplift during that period at least in the Eastern rim of the Kalahari Plateau feeding the Mozambique passive margin basin.

  9. Double-difference tomography velocity structure in Northern Oklahoma: Evidence for reduced basement velocity in the Nemaha Uplift (United States)

    Stevens, N. T.; Keranen, K. M.; Lambert, C.


    Induced seismicity in northern Oklahoma presents risk for infrastructure, but also an opportunity to gain new insights to earthquake processes [Petersen et al., 2016]. Here we present a double-difference tomographic study using TomoDD [Zhang and Thurber, 2003] in northern Oklahoma utilizing records from a dense broadband network over a 1-year period, constituting a catalog of over 10,000 local seismic events. We image a shallow (depth 4 km). We suggest that this low velocity anomaly stems from enhanced fracturing and/or weathering of the basement in the Nemaha uplift in northern Oklahoma. This velocity anomaly is not observed in basement off the shoulders of the structure, particularly to the southeast of the Nemaha bounding fault. Enhanced fracturing, and related increases to permeability, would ease pressure migration from injection wells linked to increased seismicity in the region, and may explain the relative absence of seismicity coincident with this structure compared to it periphery. References Gay, S. Parker, J. (2003), The Nemaha Trend-A System of Compressional Thrust-Fold, Strike-Slilp Structural Features in Kansas and Oklahoma, Part 1, Shale Shak., 9-49. Petersen, M. D., C. S. Mueller, M. P. Moschetti, S. M. Hoover, A. L. Llenos, W. L. Ellsworth, A. J. Michael, J. L. Rubinstein, A. F. McGarr, and K. S. Rukstales (2016), 2016 One-Year Seismic Hazard Forecast for the Central and Eastern United States from Induced and Natural Earthquakes, Open-File Rep., doi:10.3133/OFR20161035. Zhang, H., and C. H. Thurber (2003), Double-difference tomography: The method and its application to the Hayward Fault, California, Bull. Seismol. Soc. Am., 93(5), 1875-1889, doi:10.1785/0120020190.

  10. Multiscale heterogeneity characterization of tidal channel, tidal delta and foreshore facies, Almond Formation outcrops, Rock Springs uplift, Wyoming

    Energy Technology Data Exchange (ETDEWEB)

    Schatzinger, R.A.; Tomutsa, L. [BDM Petroleum Technologies, Bartlesville, OK (United States)


    In order to accurately predict fluid flow within a reservoir, variability in the rock properties at all scales relevant to the specific depositional environment needs to be taken into account. The present work describes rock variability at scales from hundreds of meters (facies level) to millimeters (laminae) based on outcrop studies of the Almond Formation. Tidal channel, tidal delta and foreshore facies were sampled on the eastern flank of the Rock Springs uplift, southeast of Rock Springs, Wyoming. The Almond Fm. was deposited as part of a mesotidal Upper Cretaceous transgressive systems tract within the greater Green River Basin. Bedding style, lithology, lateral extent of beds of bedsets, bed thickness, amount and distribution of depositional clay matrix, bioturbation and grain sorting provide controls on sandstone properties that may vary more than an order of magnitude within and between depositional facies in outcrops of the Almond Formation. These features can be mapped on the scale of an outcrop. The products of diagenesis such as the relative timing of carbonate cement, scale of cemented zones, continuity of cemented zones, selectively leached framework grains, lateral variability of compaction of sedimentary rock fragments, and the resultant pore structure play an equally important, although less predictable role in determining rock property heterogeneity. A knowledge of the spatial distribution of the products of diagenesis such as calcite cement or compaction is critical to modeling variation even within a single facies in the Almond Fin. because diagenesis can enhance or reduce primary (depositional) rock property heterogeneity. Application of outcrop heterogeneity models to the subsurface is greatly hindered by differences in diagenesis between the two settings. The measurements upon which this study is based were performed both on drilled outcrop plugs and on blocks.

  11. "Broadband" Bioinformatics Skills Transfer with the Knowledge Transfer Programme (KTP: Educational Model for Upliftment and Sustainable Development.

    Directory of Open Access Journals (Sweden)

    Emile R Chimusa


    Full Text Available A shortage of practical skills and relevant expertise is possibly the primary obstacle to social upliftment and sustainable development in Africa. The "omics" fields, especially genomics, are increasingly dependent on the effective interpretation of large and complex sets of data. Despite abundant natural resources and population sizes comparable with many first-world countries from which talent could be drawn, countries in Africa still lag far behind the rest of the world in terms of specialized skills development. Moreover, there are serious concerns about disparities between countries within the continent. The multidisciplinary nature of the bioinformatics field, coupled with rare and depleting expertise, is a critical problem for the advancement of bioinformatics in Africa. We propose a formalized matchmaking system, which is aimed at reversing this trend, by introducing the Knowledge Transfer Programme (KTP. Instead of individual researchers travelling to other labs to learn, researchers with desirable skills are invited to join African research groups for six weeks to six months. Visiting researchers or trainers will pass on their expertise to multiple people simultaneously in their local environments, thus increasing the efficiency of knowledge transference. In return, visiting researchers have the opportunity to develop professional contacts, gain industry work experience, work with novel datasets, and strengthen and support their ongoing research. The KTP develops a network with a centralized hub through which groups and individuals are put into contact with one another and exchanges are facilitated by connecting both parties with potential funding sources. This is part of the PLOS Computational Biology Education collection.

  12. Geomorphic evidences of lateral propagation and differential uplift of the two segments of frontal Siwalik range, central Himalaya, India (United States)

    Goswami, P. K.; Deopa, T.


    The Siwalik range forms the southernmost terrane of the Himalaya. The frontal mountains of this range rise abruptly against the vast Indo-Gangetic plains along the range-bounding Himalayan Frontal Thrust (HFT), which marks the present day principal displacement zone between Indian and Eurasian plates. With an aim of understanding the morphotectonics of different mountain segments in such a zone of intense tectonic activities, we have analyzed geomorphic indices like 'basin asymmetry factor' (AF), 'transverse topography asymmetry factor' (T), 'basin elongation ratio' (BR) and 'hypsometric integral' (HI) of fifty six drainage basins of 3rd streams in conjunction with 'mountain-front sinuosity' (Smf), 'valley-floor width to height ratio' (Vf) and drainage characteristics of the two large, neighboring segments of the frontal Siwalik mountains. Referred to here as the 'eastern segment' and 'western segment', these two mountain-segments are separated from each other and adjoining mountain-segments by antecedent streams of fourth and fifth order. In both the mountain-segments, the Smf values are mostly between 1.0-1.6 and, likewise, the Vf of most of the streams, calculated at a fix distance of 800m from the mountain-front, is invariably drainage basins and 65% of the eastern-segment's drainage basins indicate their down-tilting towards the west. The azimuths of the Ts of theses basins are not always in conformity with AF suggested down-tilting, but the azimuths of the larger magnitude Ts are by and large in conformity with the AF suggested down-tilting. However, the BR and HI values of all the drainage basins of a mountain-segment do not show any spatial variation. These results suggest that both the studied mountain-segments are actively uplifting, but with faster rate in their eastern part. Moreover, the drainage pattern and deflections in and around both the segments reveal their lateral progression from east to west.

  13. Onset of uplift and environmental change in East Africa: paleoaltimetry constraints from a 17 Ma beaked whale fossil from northern Kenya (United States)

    Wichura, H.; Jacobs, L. L.; Strecker, M. R.; Lin, A. S.; Polcyn, M. J.; Manthi, F. K.; Winkler, D. A.; Clemens, M.


    Deciphering the timing and magnitude of vertical crustal motions is key to understanding the impact of tectonic uplift on changes in atmospheric circulation, rainfall, and environmental conditions. Uplift of the East African Plateau (EAP) of Kenya has been linked to mantle processes, but paleoaltimetry data are still too scarce to unambiguously constrain plateau evolution and subsequent vertical motions associated with late Cenozoic rifting. Here we assess the fossil remains of a beaked whale (Ziphiidae) from the Turkana region of Kenya, 700 km inland from the present-day coastline of the Indian Ocean. The whale fossil was found at an elevation of 650 m and helps constraining the uplift of the northeastern flanks of the EAP. The Kenyan ziphiid was discovered in fluvio-lacustrine sediments of the extensional Oligo-Miocene Lokichar basin (Mead, 1975) along with terrestrial mammals and freshwater mollusks below a basalt dated at 17.1 ± 1.0 Ma (Boschetto et al., 1992). The unifying characteristics of riverine occurrences of modern marine mammals include sufficient discharge in low-gradient rivers to maintain pathways deep enough to facilitate migration, and the absence of shallow bedrock, rapids and waterfalls. The most likely route, which may have had these characteristics is a fluvial corridor controlled by thermal subsidence of the Cretaceous Anza Rift, which once linked extensional processes in Central and East Africa with the continental margin. The fossil locality and analogies with present-day occurrences of marine mammals in terrestrial realms suggest that the ziphiid stranded slightly above sea level. In combination with 13.5. Ma phonolite flows that utilized eastward-directed drainages away from the EAP the fossil find thus provides the older of only two empirical paleoelevation points that constrain the onset of uplift of the EAP to the interval between approximately 17 and 13 Ma. Topographic uplift of the EAP induced paleoclimatic change from a low

  14. Late Pleistocene-Holocene uplift driven terrace formation and climate-tectonic interplay from a seismically active intraplate setting: An example from Kachchh, Western India (United States)

    Prizomwala, S. P.; Das, Archana; Chauhan, G.; Solanki, T.; Basavaiah, N.; Bhatt, Nilesh; Thakkar, M. G.; Rastogi, B. K.


    Fluvial terrace formation is often regulated by external forcings like climate, tectonic and eustatic changes. These terraces, particularly in a dryland environment, preserves the discrete signatures of these external forcings, thus enabling us to reconstruct the fluvial response to the late Quaternary palaeoenvironmental changes and factors governing them. The present study focuses on reconstructing the aggradation/incision phases in the Lotia River which is located in the eastern segment of the Northern Hill Range (NHR) of the Kachchh Peninsula. The Lotia river drains through Mesozoic rocks before cutting across the Kachchh Mainland Fault (KMF) and finally debouch in the Banni Plains. Reconstruction based on tectonic geomorphology, sedimentology, sediment geochemistry, mineral magnetic, and OSL chronology suggests the fluvial response to monsoon variability archived during the last 15 ka. The time frame was also marked by incision enhanced by uplift along the KMF, which led to strath terrace formation. The accommodation space thus created was filled by an aggradational event between 14.8 ka and 10.6 ka. Sedimentological and geochemical parameters have also suggested that the time period between 12.5 ka and 11.5 ka showed a decline in the monsoon strength, which coincides with 'Younger Dryas'. It has been observed that the sediments spanning between 10.6 ka and 7.8 ka are absent from the archive, which is most likely the manifestation of the early Holocene optimum that led to severe erosional processes. The period between 7.8 ka and 3.3 ka is marked as another aggradational phase with fluctuating climatic conditions. At 3.3 ka, the region has experienced an incision of 4 m, which led to the formation of Holocene terrace T1, most likely due to tectonic uplift. During the last 3.3 ka, another pulsative uplift has occurred, which led to the formation of unpaired Holocene terrace T2, along with tilting of the Lotia basin. Based on the OSL chronology of bedrock strath

  15. Formation, uplift and tectonic integration of a Periadriatic intrusive complex (Pohorje, Slovenia) as reflected in magnetic parameters and palaeomagnetic directions (United States)

    Márton, Emő; Trajanova, Mirka; Zupančič, Nina; Jelen, Bogomir


    The Periadriatic lineament is a 700-km-long, first-order tectonic boundary in the Alps, along which several Tertiary intrusions are located that were emplaced while tectonic processes were active. The Pohorje pluton is one of the Periadriatic magmatic suites and comprises a pluton and a dacite stock that were emplaced at depths of about 10 and 2 km, respectively. Oriented samples were collected from 33 sites in the magmatic, and three in the surrounding metamorphic rocks and subjected them to standard palaeomagnetic and magnetic susceptibility anisotropy processing. There is extreme variation in susceptibility (although the magnetic mineral are always magnetite) and in its anisotropy within the pluton. Lowest values are in the mafic members (in the gabbro, the oldest and in some lamprophyres, the youngest member of the plutonic suite), while the tonalite (granodiorite) exhibits extreme variation, far exceeding those observed for other Periadriatic plutons. The `abnormality' of the Pohorje pluton is attributed to the complex history that involves assimilation, fractional crystallization, stratification in the magma chamber, incorporation of wall rocks, variable degree of K-metasomatism and hydrothermal alteration. Despite the above-described heterogenities and sometimes very high degree of susceptibility anisotropy (much higher that in the metamorphic samples) in the acid member, the palaeomagnetic directions observed for the pluton define three clear-cut groups. The directions show no dependence on the degree of magnetic susceptibility anisotropy. In the order of crystallization, they exhibit decreasing degree of clockwise declination deviation from north. The dacite stock is characterized by counter-clockwise rotated declinations. As the Pohorje pluton was uplifted very fast within the right-lateral Periadriatic shear zone system, it is interpreted that the palaeomagnetic directions observed for the pluton are evidence for a clockwise rotation during exhumation

  16. Spatially and temporally varying Quaternary uplift rates of the Gerecse Hills, Northern Pannonian Basin, using dated geomorphological horizons in the Danube valley (United States)

    Ruszkiczay-Rüdiger, Zsófia; Fodor, László; Csillag, Gábor; Braucher, Régis; Kele, Sándor; Novothny, Ágnes; Thamó-Bozsó, Edit; Virág, Attila; Molnár, Gábor; Madarász, Balázs; Aster Team


    The assessment of Quaternary vertical deformation rates of uplifted, low altitude hilly regions is based mainly on the dating of paleo-surfaces that can be related to reference levels through several stages of landscape evolution. Regarding the Gerecse Hills (NE part of the Transdanubian Range, Hungary), situated to the south of the incised Danube River the all-time base-level of the river provides a suitable reference level, because the intracontinental setting of the study area makes it insensitive of the global sea level changes. The terrace sequences of the Hungarian part of the Danube valley preserve a record of varying tectonic uplift rates along the river course and throughout several climate stages. The Gerecse Hills consists mainly of Triassic carbonatic rocks and a thin Paleogene and Neogene siliciclastic cover. The Danube is escorted by a set of Quaternary river terraces and higher planation surfaces, which may be of Pliocene age. The terraces are covered by alluvial sediments frequently capped by travertine and/or loess. To establish the chronology of these terraces, we rely on U-series data of travertines and on new in situ produced cosmogenic nuclides data combined with luminescence (OSL and postIR-IRSL) ages from the lower terraces. In situ produced cosmogenic 10Be concentrations were measured in samples distributed along vertical depth profiles to enable the determination of both the exposure duration and the denudation rate at each studied locality. We used Monte Carlo approach to model the denudation rate-corrected exposure ages. Burial age determinations were performed using cosmogenic 26Al/10Be nuclide ratios. Post-IR IRSL measurements were carried out on K-feldspar and OSL measurements on quartz grains to determine the ages of sediment deposition. The highest dated horizon (˜115 m above the river) provided a preliminary burial age of ˜2.7 Ma, which is in accordance with the possible time span of sedimentation deduced from the occurrence of

  17. Monitoring tectonic uplift and paleoenvironmental reconstruction for marine terraces near Maǧaracik and Samandaǧ, Hatay Province, Turkey. (United States)

    Florentin, Jonathan A; Blackwell, Bonnie A B; Tüysüz, Okan; Tarı, Ufuk; Can Genç, Ş; İmren, Caner; Mo, Shirley; Huang, Yiwen E W; Blickstein, Joel I B; Skinner, Anne R; Kim, Maria


    Near Hatay, the Antakya-Samandağ-Cyprus Fault (ASCF), East Anatolian and Dead Sea Fault Zones, the large faults that form the edges of the African, Anatolian, Cyprus and Arabian Plates, all produce large earthquakes, which have decimated Hatay repeatedly. Near Samandağ, Hatay, differential vertical displacement on the ASCF has uplifted the southeastern side relative to northwestern side, producing large fault scarps that parallel the Asi (Orontes) River. Tectonic uplift coupled with Quaternary sealevel fluctuations has produced several stacked marine terraces stranded above current sealevel. This study dated 24 mollusc samples from 10 outcrops on six marine terraces near Samandağ electron spin resonance (ESR). Ages were calculated using time-averaged and volumetrically averaged external dose rates, modelled by assuming typical water depths for the individual species and sediment thicknesses estimated from geological criteria. Uplift rates were then calculated for each fault block. At all the Mağaracık terraces, the dates suggest that many shells were likely reworked. On the 30 m terrace at Mağaracık IV (UTM 766588-3999880), Lithophagus burrows with in situ shells cross the unconformity. One such shell dated to 62 ± 6 ka, setting the minimum possible age for the terrace. For all the Mağaracık terraces at ∼30 m above mean sealevel (amsl), the youngest ages for the reworked shells, which averaged 60 ± 3 ka for six separate analyses, sets the maximum possible age for this unit. Thus, the terrace must date to 60-62 ± 3 ka, at the MIS 3/4 boundary when temperatures and sealevels were fluctuating rapidly. Older units dating to MIS 7, 6, and 5 likely were being eroded to supply some fossils found in this terrace. At Mağaracık Dump (UTM 765391-4001048), ∼103 m amsl, Ostrea and other shells were found cemented in growth position to the limestone boulders outcropping there <2.0 m above a wave-eroded notch. If the oysters grew at the same time as the wave

  18. National Assessment of Oil and Gas Project - Raton Basin-Sierra Grande Uplift Province (041) Quarter-Mile Cells (United States)

    U.S. Geological Survey, Department of the Interior — Cell maps for each oil and gas assessment unit were created by the USGS as a method for illustrating the degree of exploration, type of production, and distribution...

  19. National Assessment of Oil and Gas Project - Raton Basin-Sierra Grande Uplift Province (041) Assessment Units (United States)

    U.S. Geological Survey, Department of the Interior — The Assessment Unit is the fundamental unit used in the National Assessment Project for the assessment of undiscovered oil and gas resources. The Assessment Unit is...

  20. National Assessment of Oil and Gas Project - Raton Basin-Sierra Grande Uplift Province (041) Total Petroleum Systems (United States)

    U.S. Geological Survey, Department of the Interior — The Total Petroleum System is used in the National Assessment Project and incorporates the Assessment Unit, which is the fundamental geologic unit used for the...

  1. Upper mantle structure under western Saudi Arabia from Rayleigh wave tomography and the origin of Cenozoic uplift and volcanism on the Arabian Shield

    Energy Technology Data Exchange (ETDEWEB)

    Park, Y; Nyblade, A; Rodgers, A; Al-Amri, A


    The shear velocity structure of the shallow upper mantle beneath the Arabian Shield has been modeled by inverting new Rayleigh wave phase velocity measurements between 45 and 140 s together with previously published Rayleigh wave group velocity measurement between 10 and 45 s. For measuring phase velocities, we applied a modified array method that minimizes the distortion of raypaths by lateral heterogeneity. The new shear velocity model shows a broad low velocity region in the lithospheric mantle across the Shield and a low velocity region at depths {ge} 150 km localized along the Red Sea coast and Makkah-Madinah-Nafud (MMN) volcanic line. The velocity reduction in the upper mantle corresponds to a temperature anomaly of {approx}250-330 K. These finding, in particular the region of continuous low velocities along the Red Sea and MMN volcanic line, do not support interpretations for the origin of the Cenozoic plateau uplift and volcanism on the Shield invoking two separate plumes. When combined with images of the 410 and 660 km discontinuities beneath the southern part of the Arabian Shield, body wave tomographic models, a S-wave polarization analysis, and SKS splitting results, our new model supports an interpretation invoking a thermal upwelling of warm mantle rock originating in the lower mantle under Africa that crosses through the transition zone beneath Ethiopia and moves to the north and northwest under the eastern margin of the Red Sea and the Arabian Shield. In this interpretation, the difference in mean elevation between the Platform and Shield can be attributed to isostatic uplift caused by heating of the lithospheric mantle under the Shield, with significantly higher region along the Red Sea possibly resulting from a combination of lithosphere thinning and dynamic uplift.

  2. Canyon incision chronology based on ignimbrite stratigraphy and cut-and-fill sediment sequences in SW Peru documents intermittent uplift of the western Central Andes (United States)

    Thouret, Jean-Claude; Gunnell, Yanni; Jicha, Brian R.; Paquette, Jean-Louis; Braucher, Régis


    Based on an 40Ar/39Ar- and U/Pb-based chronostratigraphy of ignimbrite sheets and the geomorphological features of watersheds, river profiles and slope deposits in the Ocoña-Cotahuasi-Marán (OCM) and Colca valleys of southwest Peru, we reconstruct the valley incision history of the western Central Andes over the last c. 25 Myr. We further document the Pleistocene and Holocene evolution of deep valleys on the basis of 14 10Be surface-exposure ages obtained on debris-avalanche deposits and river straths. The data suggest that uplift was gradual over the past 25 Myr, but accelerated after c. 9 Ma. Valley incision started around 11-9 Ma and accelerated between 5 and 4 Ma. Incision was followed by several pulses of valley cut-and-fill after 2.3 Ma. Evidence presented suggest that the post-5 Ma sequence of accelerated canyon incision probably resulted from a combination of drainage piracy from the Cordilleran drainage divide towards the Altiplano, accentuated flexural tilting of the Western Cordillera towards the SE, and increased rainfall on the Altiplano after late Miocene uplift of the Eastern Cordillera. The valley deepening and slope steepening driven by tectonic uplift gave rise to large occurrences of rockslope failure. The collapsed rock masses periodically obstructed the canyons, thus causing abrupt changes in local base levels and interfering with the steadiness of fluvial incision. As a result, channel aggradation has prevailed in the lower-gradient, U-shaped Pacific-rim canyons, whereas re-incision through landslide deposits has occurred more rapidly across the steeper V-shaped, upper valleys. Existing canyon knickpoints are currently arrested at the boundary between the plutonic bedrock and widespread outcrops of middle Miocene ignimbritic caprock, where groundwater sapping favouring rock collapse may be the dominant process driving headward erosion.

  3. The large-scale surface uplift in the Altiplano-Puna region of Bolivia: A parametric study of source characteristics and crustal rheology using finite element analysis (United States)

    Hickey, James; Gottsmann, Joachim; del Potro, Rodrigo


    This paper focuses on the driving mechanism behind a 70 km wide region of ground uplift centered on Uturuncu volcano, in the Altiplano-Puna region of southern Bolivia. We present a series of forward models using finite element analysis to simultaneously test for first-order parameters that help constrain a viable model for the observed maximum line of sight uplift rate of 1-2 cm/yr between 1992 and 2006. Stresses from pressure sources with finite geometries are solved numerically, accounting for both homogeneous and heterogeneous mechanical rock properties in elastic and viscoelastic rheologies. Crustal heterogeneity is constrained by seismic velocity data that indicate the presence of a large low-velocity zone, the Altiplano-Puna magma body, at depths of 17 km below the surface. A viscoelastic rheology is employed to account for time-dependent deformation and an inelastic crust. Comparing homogeneous and heterogeneous models demonstrates the significant impact of a mechanically weak, source-depth layer, which alters surface displacement patterns by buffering subsurface deformation. Elastic model results guide the source parameters tested in the viscoelastic models and demonstrate a range of possible causative source geometries. Our preferred model suggests that pressurization of a magma source extending upward from the Altiplano-Puna magma body is causing the observed surface uplift and alludes to a continued increase in this pressure to explain both the spatial and temporal patterns. We also demonstrate how a pressure-time function plays a first-order role in explaining the observed temporal deformation pattern.

  4. Rupture parameters of the 2003 Zemmouri (Mw 6.8), Algeria, earthquake from joint inversion of interferometric synthetic aperture radar, coastal uplift, and GPS (United States)

    Belabbes, S.; Wicks, Charles; Cakir, Z.; Meghraoui, M.


    We study the surface deformation associated with the 21 May 2003 (M w = 6.8) Zemmouri (Algeria) earthquake, the strongest seismic event felt in the Algiers region since 1716. The thrust earthquake mechanism and related surface deformation revealed an average 0.50 m coastal uplift along ??55-km-long coastline. We obtain coseismic interferograms using Envisat advanced synthetic aperture radar (ASAR) (IS2) and RADARSAT standard beam (ST4) data from both the ascending and descending orbits of Envisat satellite, whereas the RADARSAT data proved useful only in the descending mode. While the two RADARSAT interferograms cover the earthquake area, Envisat data cover only the western half of the rupture zone. Although the interferometric synthetic aperture radar (InSAR) coherence in the epicenter area is poor, deformation fringes are observed along the coast in different patches. In the Boumerdes area, the maximum coseismic deformation is indicated by the high gradient of fringes visible in all interferograms in agreement with field measurements (tape, differential GPS, leveling, and GPS). To constrain the earthquake rupture parameters, we model the interferograms and uplift measurements using elastic dislocations on triangular fault patches in an elastic and homogeneous half-space. We invert the coseismic slip using first, a planar surface and second, a curved fault, both constructed from triangular elements using Poly3Dinv program that uses a damped least square minimization. The best fit of InSAR, coastal uplift, and GPS data corresponds to a 65-km-long fault rupture dipping 40?? to 50?? SE, located at 8 to 13 km offshore with a change in strike west of Boumerdes from N60??-65?? to N95??-105??. The inferred rupture geometry at depth correlates well with the seismological results and may have critical implications for the seismic hazard assessment of the Algiers region. Copyright 2009 by the American Geophysical Union.

  5. Mantle plumes & lithospheric foundering: Determining the timing and amplitude of post-Miocene uplift in the Wallowa mountains, north-east Oregon with low-temperature thermochronometry. (United States)

    Schoettle-Greene, P.; Duvall, A. R.


    The foundering of gravitationally unstable lithosphere, while frequently invoked to explain anomalous topography, proves difficult to verify from an Earth surface perspective. Theoretically, direct observables like sudden uplift associated with extension and mantle-sourced volcanism should help identify affected regions but these markers are often obscured by background stresses and heterogeneous lithosphere. To better understand topographic evolution following the removal of mantle lithosphere, we present new apatite U-Th/He thermocrhonometry data and field observations from the Wallowa mountains adjacent to Hells Canyon in the northwestern United States. The granodiorite-cored Wallowa are increasingly recognized as a type locality for the process of lithospheric foundering, as they are bound by extensional structures and were presumably uplifted contemporaneous with the intrusion of feeder dikes for the mantle-sourced Columbia River Basalts at 16 Ma. Cretaceous and early Cenozoic cooling ages from our study imply that in spite of the presumed 1-2 km of basalt flows eroded from the Wallowa and heating associated with the intrusion of the Chief Joseph dike swarm, and 2 km of proposed rapid post-foundering uplift, there has been little exhumation. We attempt to reconcile these conflicting observations with field mapping of folded basalt flows at the margins of the Wallowa mountains, modeling of geothermal response times following a thermal perturbation, and further study using the 4He/3He thermochronometer on a subset of samples to reveal more recent cooling histories. Our findings will improve our understanding of the landscape evolution of the Wallowa mountains, information pertinent to the geodynamics of lithosphere removal and the eruption of Columbia River Basalts.

  6. Uplift Sequence of the Main Morphoestructural Units of the South Central Andes at 30°S: Insights from a Multidisciplinary Approach (United States)

    Lossada, A. C.; Mardónez, D.; Suriano, J.; Hoke, G. D.; Fitzgerald, P. G.; Mahoney, J. B.; Giambiagi, L.; Aragon, E.


    The South Central Andes at 30°S represent a key area to understand the Andes geodynamics as it corresponds to the flat slab segment, characterized by a subhorizontal subduction angle, absence of Neogene magmatism and a highly compressive tectonic regime. Under these settings, crustal shortening is believed to be the principal mechanism responsible for the rise of the Andes. However, the sequence of uplift of the different morphoestructural units composing the orogen is not fully understood; neither do the location and time of activity of intracrustal detachments and their connection with shallower structures. We attempt to develop a multidisciplinary analysis that allow us to characterize the timing, magnitude and activity of the principal structures involved in the construction of the Andes at 30°S trough the Coastal Range, the Frontal Cordillera and the Precordillera. The main phase of deformation in the Coastal Range occurred between 60 and 40Ma, based on published thermochronological and structural data. Our structural analyses constrain the Frontal Cordillera uplift between 18 and 13Ma. In the Precordillera area, in turn, we carried out structural, sedimentological and U-Pb provenience studies. Provenience studies and the 12 and 9Ma ages obtained for the youngest zircons indicated that the main thrusts uplifting the western sector of the Precordillera thrust system were activated since 13Ma at this latitude, and not before that time as it was previously suggested. In order to better constrain the exhumation and thermal history of Frontal Cordillera, a thermochronological study is being conducted. Twenty samples for apatite fission tracks (AFT) and apatite (U-Th)/He (AHe) were collected from two vertical profiles located at western sector (Guanta granitoid) and eastern sector (Colanguil granitoid) of the Frontal Cordillera system. Samples are currently being processed, and they are partially reseted, which will allow us to obtain a cooling age. The aim is to

  7. Extensional tectonics, basement uplift and Stephano-Permian collapse basin in a late Variscan metamorphic core complex (Montagne Noire, Southern Massif Central) (United States)

    Echtler, H.; Malavieille, J.


    The Montagne Noire is interpreted as a Variscan metamorphic core complex composed of: (1) an uplifted core of assumed Proterozoic gneisses and migmatitic rocks associated with anatectic granites related to a late Hercynian LP/HT metamorphism and (2) an upper plate composed of low-grade or non-metamorphic folded Palaeozoic sediments. These two units are separated by normal and wrench/normal ductile shear zones and detachment faults. These fault zones are characterized by synmetamorphic S- C type mylonites and stretching lineations superimposed on the earlier compressional deformation features. Early orogenic shortening is marked by polyphase, large-scale folding in the core rocks (Axial Zone) and in the thrust nappes of the upper plate. The late Variscan evolution of this massif is in general characterized by extensional tectonics. Kinematic analysis of the extensional deformation shows that displacement on the fault zones is parallel to retrogressive stretching lineations. Shear sense criteria indicate an upper plate movement towards the northeast in the northeastern part of the massif, and towards the south-southwest in the southwestern part. At the same time, transcurrent right-lateral movements occurred along the subvertical ENE-trending boundaries of the core zone. The late orogenic extensional tectonism in the Montagne Noire is attributed to uplift of the previously thickened core zone controlled by an extensional stage between two right-lateral wrench fault zones. Associated with the late Hercynian metamorphic core complex, a Stephano-Permian continental sedimentary basin was formed along the active detachment to the northeast of the uplifted core. The tectonic fabric of the basal coarse clastic Stephanian sediments shows an extension parallel to the ductile stretching in the underlying extensional shear zones. The geometry of unconformably layered clastic sequences, synsedimentary brittle faults, and the various deformation features are consistent with

  8. "Suntelligence" Survey (United States)

    ... the American Academy of Dermatology's "Suntelligence" sun-smart survey. Please answer the following questions to measure your ... how you incorporate it into your life. The survey will take 5 to 7 minutes to complete. ...

  9. Taxonomic composition and biostratigraphic value of the Early Riphean organic-walled microfossil association from the Ust'-Il'ya Formation of the Anabar Uplift, Northern Siberia (United States)

    Sergeev, V. N.; Vorob'eva, N. G.; Petrov, P. Yu.; Semikhatov, M. A.


    It is demonstrated on the basis of the first monographic study of multiple and taxonomically variable organic-walled microfossils from the Ust'-Il'ya Formation of the Anabar Uplift that both prokaryotic and eukaryotic forms are present in the composition of this microbiota. They are divided into four formal groups on the basis of the specifics of the morphological indicators of the identified taxa. The review of the data on the isotopic age of hosting deposits showed that the Ust'-Il'ya Formation is of the Early Riphean in age which are currently evaluated as 1750 ± 10-1400 Ma. Relatively large and morphologically complex eukaryotic forms present in the Ust'-Il'ya Formation served in due time as the basis for an erroneous conclusion on the Late Riphean age of the specified formation and the overlying Lower Kotuikan Subformation of the Anabar Uplift. The paper provides a global comparative analysis of the Early Riphean microbiotas, demonstrates the position of the Ust'-Il'ya and Kotuikan microbiotas amidst the microbiotas of the same age, and shows that the relatively large acanthomorphic acritarchs Tappania, Valeria, Dictiosphaera, Satka, and Shuiyousphaeridium appeared in the geological history already during the Early Riphean Erathem. Moreover, the paper discusses the recently published data on the distribution of aerobic and anaerobic conditions in the Early Riphean paleobasins and provides the conclusion on the impact of the lateral change of these conditions on the taxonomic composition of the microbiota.

  10. Gravimetric structure for the abyssal mantle massif of Saint Peter and Saint Paul peridotite ridge, Equatorial Atlantic Ocean, and its relation to active uplift

    Directory of Open Access Journals (Sweden)



    Full Text Available This paper presents gravimetric and morphologic analyses based on the satellite-derived data set of EGM2008 and TOPEX for the area of the oceanic mantle massif of the Saint Peter and Saint Paul peridotite ridge, Equatorial Atlantic Ocean. The free-air anomaly indicates that the present plate boundary is not situated along the longitudinal graben which cuts peridotite ridge, but about 20 km to the north of it. The high Bouguer anomaly of the peridotite ridge suggests that it is constituted mainly by unserpentinised ultramafic rocks. The absence of isostatic compensation and low-degree serpentinisation of the ultramafic rocks indicate that the peridotite ridge is sustained mainly by active tectonic uplift. The unparallel relation between the transform fault and the relative plate motion generates near north-south compression and the consequent tectonic uplift. In this sense, the peridotite massif is a pressure ridge due to the strike-slip displacement of the Saint Paul Transform Fault.

  11. What Makes Underwriting and Non-Underwriting Clients of Brokerage Firms Receive Different Recommendations? An Application of Uplift Random Forest Model

    Directory of Open Access Journals (Sweden)

    Shaowen Hua


    Full Text Available I explore company characteristics which explain the difference in analysts’ recommendations for companies that were underwritten (affiliated versus non-underwritten (unaffiliated by analysts’ brokerage firms. Prior literature documents that analysts issue more optimistic recommendations to underwriting clients of analysts’ brokerage employers. Extant research uses regression models to find general associations between recommendations and financial qualities of companies, with or without underwriting relationship. However, regression models cannot identify the qualities that cause the most difference in recommendations between affiliated versus unaffiliated companies. I adopt uplift random forest model, a popular technique in recent marketing and healthcare research, to identify the type of companies that earn analysts’ favor. I find that companies of stable earnings in the past, higher book-to-market ratio, smaller sizes, worsened earnings, and lower forward PE ratio are likely to receive higher recommendations if  they are affiliated with analysts than if they are unaffiliated with analysts. With uplift random forest model, I show that analysts pay more attention on price-related than earnings-related matrices when they value affiliated versus unaffiliated companies. This paper contributes to the literature by introducing an effective predictive model to capital market research and shedding additional light on the usefulness of analysts’ reports.

  12. Geological and geochronological evidence for the effect of Paleogene and Miocene uplift of the Northern Ordos Basin on the formation of the Dongsheng uranium district, China (United States)

    Zhang, Chuang; Yi, Chao; Dong, Qian; Cai, Yu-Qi; Liu, Hong-Xu


    The Dongsheng uranium district, located in the northern part of the Ordos Basin, contains the largest known sandstone-hosted uranium deposit in China. This district contains (from west to east) the Daying, Nalinggou, and Dongsheng uranium deposits that host tens of thousands of metric tonnes of estimated recoverable uranium resources at an average grade of 0.05% U. These uranium orebodies are generally hosted by the lower member of the Zhiluo Formation and are dominantly roll or tabular in shape. The uranium deposits in this district formed during two stages of mineralization (as evidenced by U-Pb dating) that occurred at 65-60 and 25 Ma. Both stages generated coffinite, pitchblende, anatase, pyrite, and quartz, with or without sericite, chlorite, calcite, fluorite, and hematite. The post-Late Cretaceous uplift of the Northern Ordos Basin exposed the northern margins of the Zhiluo Formation within the Hetao depression at 65-60 Ma, introducing groundwater into the formation and generating the first stage of uranium mineralization. The Oligocene (∼25 Ma) uplift of this northern margin exposed either the entirety of the southern flank of the Hetao depression or only the clastic sedimentary part of this region, causing a second gravitational influx of groundwater into the Zhiluo Formation and forming the second stage of uranium mineralization.

  13. Late Quaternary Surface Rupture and Associated Transpressive Uplift on a Section of the State Line Fault in the south-central Amargosa Desert Basin, Southwestern Nevada (United States)

    Menges, C. M.; Fridrich, C.; Blakely, R. J.; Thompson, R. A.


    New geomorphic, geophysical, and structural data indicate that a section of the Pahrump-Stewart Valley (State Line) fault on the northern piedmont of the Resting Spring Range is associated with late Quaternary surface rupture and related transpressive domal uplift. Detailed aeromagnetic and gravity data clearly image this northwest-trending strike-slip fault in the subsurface as a continuous multi-strand fault system that continues >35 km further northwest into the south-central Amargosa Desert basin than previously established. This continuation of the fault consists of a sigmoidal bend characterized by a constraining bend on the north flank of the Resting Spring Range, paired with a releasing bend on the north flank of the southeastern Funeral Mountains. Bedrock mapping in the Amargosa Desert indicates a cumulative late Cenozoic right-lateral displacement of ˜15 km across the entire fault zone. In the Resting Spring area, the major central strand of the State Line fault zone is inactive but offsets playa facies of the Artists Drive Formation (equivalent), internally folded into a giant southeast-plunging chevron syncline, against fluvial and playa margin facies of the same formation that are folded into a broad northwest-plunging anticline. These deformed Tertiary strata are exposed in the core of a large (10 x 18 km) domal Quaternary uplift, centered on the northern piedmont of the range, that coincides with a major transpressive left-step in the adjoining active trace of the fault zone. The domal uplift is indicated by persistent incision into Tertiary bedrock (1-5+ m deep) beneath stepped sequences of straths capped by thin and locally warped mid-Pleistocene to Holocene alluvial-gravel veneers. Quaternary activity on the fault zone in this area is now focused on a strand along the northern and eastern border of the uplifted area marked by a discontinuous, 8-10 km long series of aligned, en-echelon, or anastomosing fault scarps that commonly bound linear

  14. Patterns of deformation, exhumation and uplift across the Island of Timor: insights into the processes that control the early stages of orogenesis (Invited) (United States)

    McQuarrie, N.; Tate, G. W.; Van Hinsbergen, D. J.; Harris, R. A.


    On the island of Timor, arc-continent collision between the Banda volcanic arc and the Australian continent since the late Miocene has uplifted a mountain range containing both deeply exhumed metamorphic rocks and deepwater synorogenic basins. These varied lithologies are separated by a few tens of kilometers, and provide us with an opportunity to examine the spatial patterns of differential uplift and exhumation and its links to the geometry and magnitude of deformation in an orogen that is still in its infancy. New mapping in Timor has provided a detailed view of how the Australian continental slope and shelf rocks are being structurally repeated below overriding Banda Arc material. In East Timor, a window though the Banda terrane shows Permian and Triassic rocks that are repeated by four NNE-striking thrust faults with ~3 km spacing and 50-75 km along-strike extent. The strike of these faults is rotated 50-60 degrees compared to structures to the east and west of this main window. In addition, mapped fold axes are shown to cut across and warp fault traces. These map patterns indicate that the duplex has been both refolded and tilted since its initial formation. In West Timor, Permian through Triassic stratigraphy is faulted and folded into an antiformal stack with 5 exposed thrusts repeating an ~ 3 km thick section. Both south of and adjacent to these structural highs are 10-20 km wide piggyback basins of deepwater, synorogenic marine limestones and clays that coarsen upward into turbidites. Deposition of these units initiated at 5.5 Ma at lower bathyal depths. Synorogenic deposition directly over the Bobonaro mélange, which acts as the décollement between the overthrust Banda Arc rocks and the structurally repeated Australian margin rocks, requires the removal of both Banda arc material and the Cretaceous and younger Kolbano sequence before deposition. These basins record rapid surface uplift to upper bathyal depths from 3.5-3 Ma with continual uplift to

  15. Late Miocene to present-day exhumation and uplift of the Internal Zone of the Rif chain: Insights from low temperature thermochronometry and basin analysis (United States)

    Romagny, A.; Ph. Münch; Cornée, J.-J.; Corsini, M.; Azdimousa, A.; Melinte-Dobrinescu, M. C.; Drinia, H.; Bonno, M.; Arnaud, N.; Monié, P.; Quillévéré, F.; Ben Moussa, A.


    Located on the margin of the west Alboran basin, the Gibraltar Arc (Betic-Rif mountain belt) displays post-Pliocene vertical movements evidenced by uplifted marine sedimentary basins and marine terraces. Quantification of vertical movements is an important clue to understand the origin of present-day relief generation in the Betic-Rif mountain chain together with the causes of the Messinian Salinity Crisis. In this paper, we present the results of a pluridisciplinary study combining an analysis of low temperature thermochronology and Pliocene basins evolution to constrain the exhumation history and surface uplift of internals units of the Rif belt (Northern Morocco). The mean (U-Th)/He apatite ages obtained from 11 samples are comprised between 14.1 and 17.8 Ma and display a wide dispersion, which could be explained by a great variability of apatite chemistries in the analyzed samples. No correlations between altitude and age have been found along altitudinal profile suggesting a rapid exhumation during this period. Thermal modeling using our (U-Th)/He apatite ages and geochronological data previously obtained in the same area (40Ar/39Ar and K/Ar data on biotite, zircon and apatite fission track) allow us to propose a cooling history. The rocks suffered a rapid cooling at 60-100 °C/Ma between 22.5 and 19 Ma, then cooled to temperatures around 40 °C between 19 and 18 Ma. They were re-heated at around 110 °C between 18 and 15 Ma then rapidly cooled and exhumed to reach the surface temperature at around 13 Ma. The re-heating could be related to a renewal in thrusting and burying of the inner zones. Between 15 and 13 Ma the cooling resumed at a rate of 50 °C/Ma indicating an exhumation rate of 0.8 mm/y considering an average 40 °C/km geothermal gradient. This exhumation may be linked to the extension in the Alboran Sea. Otherwise biostratigraphic and sedimentological analysis of Pliocene basins of the internal Rif provided informations on the more recent events

  16. Sky Surveys


    Djorgovski, S. G.; Mahabal, A. A.; Drake, A.J.; Graham, M. J.; C. Donalek


    Sky surveys represent a fundamental data basis for astronomy. We use them to map in a systematic way the universe and its constituents, and to discover new types of objects or phenomena. We review the subject, with an emphasis on the wide-field imaging surveys, placing them in a broader scientific and historical context. Surveys are the largest data generators in astronomy, propelled by the advances in information and computation technology, and have transformed the ways in which astronomy is...

  17. A 7.3-1.6 Ma grain size record of interaction between anticline uplift and climate change in the western Qaidam Basin, NE Tibetan Plateau (United States)

    Lu, Yin; Fang, Xiaomin; Appel, Erwin; Wang, Jiuyi; Herb, Christian; Han, Wenxia; Wu, Fuli; Song, Chunhui


    How sediment grain size corresponds to both climate change and tectonics is increasingly the focus of debate. The shrinkage and migration of the huge paleo-lake in the western Qaidam Basin (WQB), NE Tibetan Plateau (TP) provide an excellent case study. We present a nearly 6 Ma well-dated high-resolution grain size record from the 723-m-deep drill core SG-1b (located in the Jianshan Anticline in the WQB) to show how sediment grain size responds to anticline growth and climate change. The results show that variations in grain size represent three distinct phases. Phase I (7.3-3.6 Ma) is characterized by fine sediments with good sorting, with a predominance of clay and fine silt. During this phase, the drilling site was in a deep to semi-deep lake environment, the Jianshan Anticline has undergone relatively weak tectonics and the climate was dry, but still much wetter than that in the Quaternary; grain size variation and lacustrine deposition were principally controlled by climate. Phase II ( 3.6-3.3 Ma) was a transitional period characterized by a rapid shift toward consistently coarser sediments with increased volumes of medium-coarse silt and sand. During this phase, the drilling site underwent a dramatic shift to a shallow lake environment, the anticline experienced rapid uplift and the climate was in an episode of rapid drying; grain size variation and lacustrine deposition were principally controlled by tectonics in the Jianshan Anticline. Phase III ( 3.3-1.6 Ma) was a period exhibiting a long-term fining trend in mean grain size relative to Phase II, but still much coarser than that of Phase I, and with a distinct and prolonged increase in very fine sediments accompanied by poor sorting. During this phase, the drilling site was in a shallow lake environment between 3.3 Ma and 1.9 Ma, and finally became a lakeshore-like environment between 1.9 Ma and 1.6 Ma; the anticline experienced rapid and continuous uplift and the climate was in a long-term stepwise drying

  18. Uplifted ophiolitic rocks on Isla Gordon, southernmost Chile: implications for the closure history of the Rocas Verdes marginal basin and the tectonic evolution of the Beagle Channel region (United States)

    Cunningham, W. D.


    A succession of mafic rocks that includes gabbro, sheeted dikes and deformed pillow basalts has been mapped in detail on Isla Gordon, southernmost Chile and is identified as an upper ophiolitic complex representing the uplifted floor of the Late Jurassic-Early Cretaceous Rocas Verdes marginal basin. The complex was uplifted, deformed, and regionally metamorphosed prior to the intrusion of an undeformed 90 Ma granodiorite that cuts the complex. The complex appears para-autochthonous, is gently tilted to the northeast and is internally sheared by near-vertical foliation zones. No evidence for obduction was observed although the base of the complex is not exposed. The ophiolitic rocks have been regionally metamorphosed to mid-upper greenschist levels. Isla Gordon is bounded by the northwest and southwest arms of the Beagle Channel, two important structural boundaries in the southernmost Andes that are interpreted to have accommodated north-side-up and left-lateral displacements. Directly north of Isla Gordon is the Cordillera Darwin metamorphic complex that exposes the highest grade metamorphic rocks in the Andes south of Peru. On the north coast of Isla Gordon a volcaniclastic turbidite sequence that is interpreted to have been deposited above the mafic floor is metamorphosed to lower greenschist levels in strong metamorphic contrast to amphibolite-grade othogneisses exposed in Cordillera Darwin only 2 km away across the northwest arm of the Beagle Channel. The profound metamorphic break across the northwest arm of the Beagle Channel and the regional northeast tilt of the ophiolitic complex are consistent with the previously proposed hypothesis that Isla Gordon represents the upper plate to an extensional fault that accommodated tectonic unroofing of Cordillera Darwin. However, limited structural evidence for extension was identified in this study to support the model and further work is needed to determine the relative importance of contractional, extensional and

  19. Development of a shelf margin delta due to uplift of Munkagrunnur Ridge at the margin of Faroe-Shetland Basin: a seismic sequence stratigraphic study

    DEFF Research Database (Denmark)

    Òlavsdóttir, Jana; Boldreel, Lars Ole; Andersen, Moretn S


    are observed within several units and, with additional information regarding the seismic character and nature of internal unconformities and systems tracts, the nine seismic units are divided into systems tracts deposited during eight cycles of relative sea level change. Within the study area falling stage...... and lowstand systems tracts (FSST and LSST) are generally better preserved than transgressive and highstand systems tracts (TSST and HSST). Maximum flooding surfaces separating a TSST from the overlying HSST are not recognized, and in several sequences the TSST and HSST are either absent or so thin...... curve indicates that the Faroe-Shetland Basin was characterized by almost continuous relative sea level rise in the mid Eocene. Multiple stages of uplift of the Munkagrunnur Ridge during the mid-Eocene are considered to be the most likely explanation for the multiple cycles of sea level change inferred...

  20. Neogene-Quaternary slow coastal uplift of Western Europe through the perspective of sequences of strandlines from the Cotentin Peninsula (Normandy, France) (United States)

    Pedoja, K.; Jara-Muñoz, J.; De Gelder, G.; Robertson, J.; Meschis, M.; Fernandez-Blanco, D.; Nexer, M.; Poprawski, Y.; Dugué, O.; Delcaillau, B.; Bessin, P.; Benabdelouahed, M.; Authemayou, C.; Husson, L.; Regard, V.; Menier, D.; Pinel, B.


    The Cotentin Peninsula (Normandy, France) displays sequences of marine terraces and rasas, the latter being wide Late Cenozoic coastal erosion surfaces, that are typical of Western European coasts in Portugal, Spain, France and southern England. Remote sensing imagery and field mapping enabled reappraisal of the Cotentin coastal sequences. From bottom to top, the N Cotentin sequence includes four previously recognized Pleistocene marine terraces (T1 to T4) at elevations France, the sequences morphostratigraphy is very similar to that of Cotentin. The onset of such Western European sequences occurred during the Miocene (e.g. Spain) or Pliocene (e.g. Portugal). We interpret this Neogene-Quaternary coastal uplift as a symptom of the increasing lithospheric compression that accompanies Cenozoic orogenies.

  1. Uplift-driven sediment redness decrease at ~16.5 Ma in the Yumen Basin along the northeastern Tibetan Plateau (United States)

    Wang, Weitao; Zhang, Peizhen; Zheng, Wenjun; Zheng, Dewen; Liu, Caicai; Xu, Hongyan; Zhang, Huiping; Yu, Jingxing; Pang, Jianzhang


    Significant climate shifts in the northeastern Tibetan Plateau have taken place during the Cenozoic, but the reasons behind them remain unclear. In order to unravel the mechanisms driving these climate changes, proxy data with accurate age constraint are needed. Here we present magnetostratigraphy, sediment color (redness a*, and lightness L*) and grain-size analysis from an early to middle Miocene (~20-15.3 Ma) sediment sequence preserved in the Yumen Basin on the northeastern Tibetan Plateau. In this basin, remarkable increase in lightness, decreases in redness and in ratio of hematite (Hm) to goethite (Gt) took place at ~16.5 Ma. We suggest that these changes result from shorter duration of weathering, climatic wetting, and cooling associated with rapid uplift of the Qilian Shan at the middle Miocene.

  2. Sky Surveys (United States)

    Djorgovski, S. George; Mahabal, Ashish; Drake, Andrew; Graham, Matthew; Donalek, Ciro

    Sky surveys represent a fundamental data basis for astronomy. We usethem to map in a systematic way the universe and its constituents andto discover new types of objects or phenomena. We review the subject,with an emphasis on the wide-field, imaging surveys, placing them ina broader scientific and historical context. Surveys are now the largestdata generators in astronomy, propelled by the advances in informationand computation technology, and have transformed the ways in whichastronomy is done. This trend is bound to continue, especially with thenew generation of synoptic sky surveys that cover wide areas of the skyrepeatedly and open a new time domain of discovery. We describe thevariety and the general properties of surveys, illustrated by a number ofexamples, the ways in which they may be quantified and compared, andoffer some figures of merit that can be used to compare their scientificdiscovery potential. Surveys enable a very wide range of science, and that isperhaps their key unifying characteristic. As new domains of the observableparameter space open up thanks to the advances in technology, surveys areoften the initial step in their exploration. Some science can be done withthe survey data alone (or a combination of data from different surveys),and some require a targeted follow-up of potentially interesting sourcesselected from surveys. Surveys can be used to generate large, statisticalsamples of objects that can be studied as populations or as tracers of largerstructures to which they belong. They can be also used to discover orgenerate samples of rare or unusual objects and may lead to discoveriesof some previously unknown types. We discuss a general framework ofparameter spaces that can be used for an assessment and comparison ofdifferent surveys and the strategies for their scientific exploration. As we aremoving into the Petascale regime and beyond, an effective processing andscientific exploitation of such large data sets and data streams pose

  3. Tilting of Lake Pielinen, eastern Finland – an example of extreme transgressions and regressions caused by differential post-glacial isostatic uplift

    Directory of Open Access Journals (Sweden)

    Heikki Seppä


    Full Text Available Tilting of large lakes due to differential isostatic uplift in the glaciated regions of the Northern Hemisphere is a well-documented process. With the help of accurate digital elevation models and spatial GIS analysis techniques, the resulting hydro­logical changes, including shifts in the outlets and changes in the size and configuration of lakes, can now be mapped and calculated more precisely than before. As a case study to highlight the magnitude of such changes in Fennoscandia, we investigated and reinterpreted the Holocene palaeogeography and palaeohydrology of Lake Pielinen in eastern Finland. This lake is currently 99 km long and located parallel to the direction of land uplift, being thus particularly sensitive to the impacts of tilting. Our results show that the lake was formed at the end of the regional deglaciation, following drainage of a local ice-dammed lake. In its initial stage until 10 200 cal yr BP, the outlet of the newly-formed lake was located in its northwestern end, but the tilting led to a major water level transgression in the basin, eventually causing formation of a new outlet over the southeastern threshold. The lake area was 143 km long and its area was 1998 km2 at the time of formation of the southeastern outlet at 10 200 cal yr BP. The lake level has been regressive throughout the basin during the last 10 200 years. This regression will continue for approximately another 10 000 years until all the glacial isostatic adjustment has occurred, after which Lake Pielinen will be only 89 km long and 565 km2 in area.

  4. Zircon Hf isotopic constraints on the mantle source of felsic magmatic rocks in the Phan Si Pan uplift and Tu Le basin, northern Vietnam (United States)

    Usuki, T.; Lan, C.; Tran, T.; Pham, T.; Wang, K.


    Permian plume-related rocks, such as picrites, flood basalts and silicic volcanic rocks occur in northern Vietnam. This area was displaced 600 km southeastward along the Ailao Shan-Red River fault during mid-Tertiary in response to the India-Eurasia collision. The original location of the area was situated at the central Emeishan Large Igneous Province (ELIP) in SW China before Tertiary. The picrites and flood basalts in northern Vietnam have been investigated by many authors and are comparable with the ELIP. While, felsic magmatisms in northern Vietnam has been poorly studied. Zircon U-Pb age and Hf isotopic data are useful to compare the felsic magmatism in northern Vietnam with that in the ELIP, because the magmatisms of the ELIP had a characteristic time period (260-250 Ma) and the Hf isotopes show a remarkable mantle signature. Therefore, this study carried out in-situ U-Pb ages and Hf isotopic compositions for 300 zircon grains in eighteen granitoids and rhyolites in Phan Si Pan uplift and Tu Le basin in northern Vietnam. Zircons from the granitoids and rhyolites occasionally show development of {101} pyramid and {100} prism crystal facies, suggesting typical zircons crystallized from high temperature alkaline granite. 206Pb/238U ages of granitoid and rhyolite yield consistently in a narrow range of 260 to 250 Ma, which coincides with those from peralkaline to metaluminous granites in the ELIP. ɛHf(t) values of zircons in rhyolites and granites of this study dominate in the range of +5 to +10, which is consistent with those from the ELIP. U-Pb ages and Hf isotopic compositions of zircons indicate that felsic magmatic rocks in the Phan Si Pan uplift and Tu La basin have been derived from the same mantle source with the ELIP.

  5. Microfacies and depositional environments of the Late Ordovician Lianglitage Formation at the Tazhong Uplift in the Tarim Basin of Northwest China (United States)

    Gao, Da; Lin, Changsong; Yang, Haijun; Zuo, Fanfan; Cai, Zhenzhong; Zhang, Lijuan; Liu, Jingyan; Li, Hong


    The Late Ordovician Lianglitage Formation comprises 13 microfacies (Mf1-Mf13) that were deposited on a carbonate platform at the Tazhong Uplift of the Tarim Basin in Northwest China. Each type of microfacies indicates a specific depositional environment with a certain level of wave energy. Four primary groups of microfacies associations (MA1-MA4) were determined. These associations represent different depositional facies, including reef-shoal facies in the platform margin (MA1), carbonate sand shoal facies (MA2) and oncoid shoal (MA3) on open platforms, and lagoon and tidal flat facies (MA4) in the platform interior. Each microfacies association was generated in a fourth-order sedimentary sequence developing within third-order sequences (SQ1, SQ2, and SQ3, from bottom to top), showing a shallowing-upward trend. High-frequency sequences and facies correlation between wells suggests that the reef-shoal facies more successively developed in the southeastern part of the platform margin, and high-energy microfacies were more strictly confined by the top boundary of fourth-order sequences in the northwestern part of the platform. The highstand systems tract (HST) of the SQ2 is characterized by reef-shoals that developed along the platform margin and tidal flats and lagoons that developed in the platform interior, while the SQ3 is characterized by the oncoid shoal facies that generally developed on the uplift due to a regionally extensive transgression that occurred during the latter part of the Late Ordovician. The results of this study can be used for investigating the development and distribution of potential reservoirs; the reservoirs in southeastern part of the platform margin may be of premium quality because the high-energy microfacies were best preserved there.

  6. Plate boundary behaviour, recent uplift, and seismic hazard along the Central Alpine Fault near the Whataroa River, South Island, New Zealand (United States)

    De Pascale, G. P.; Davies, T. R.


    Understanding plate boundary behaviour is a major objective in seismotectonics to better understand and mitigate seismic hazards. Field- and light detection and ranging (lidar)-derived topographic mapping, geological characterisation, and optically stimulated luminescence (OSL) dating of on-fault sediments were used to better constrain rangefront deformation of the Southern Alps at the Alpine Fault near the Whataroa River. The Alpine Fault, which forms the plate boundary in the South Island of New Zealand, is thought to rupture in large to great earthquakes (most recently in 1717 AD). Here the fault is dextral-reverse, although primarily strike-slip with clear fault traces cutting across older surfaces of varying elevations and ages. Deformational bulges are observed along these traces that are likely thrust-bounded. A terrace of Whataroa River sediments on the hanging wall of the fault approximately ~ 55-75 m (when considering uncertainties) above the floodplain of the Whataroa. OSL ages for hanging wall sediments of ~ 11 ka in this terrace, ~ 2.8 ka for Whataroa River terrace deposits in a deformational bulge, and ~ 11.1 ka for a rangefront-derived fan and aggradation along the rangefront and Holocene hanging wall uplift rates of ~6.0 + or - 1 mm/yr at the fault. These Whataroa River-sourced terrace deposits suggest that the adjacent bounding faults are steeply-dipping, with no geometries in the shallow subsurface that would tend to cause rotation and tilting. Because GPS-derived "interseismic" vertical uplift rates are new outcrop mapping that demonstrates other important sources of seismic hazard exist near this plate boundary.

  7. Late Cenozoic magnetostratigraphy and anisotropy of magnetic susceptibility of the Baiyanghe section from the Hoxtolgay Basin: Implications for the uplift of the West Junggar Mt Range, NW China (United States)

    Ai, Keke; Ji, Junliang; Wang, Guocan; Zhang, Kexin; Tang, Zihua


    To better constrain the tectonic evolution of Central Asia under the influence of the India-Asia collision, we performed combined magnetostratigraphy and anisotropy of magnetic susceptibility (AMS) analysis of the Baiyanghe section on the northern margin of the Hoxtolgay Basin (West Junggar Mt Range, northwestern China). The observed magnetostratigraphy shows a total of 14 pairs of normal and reversed geomagnetic polarity zones in the well-exposed ∼360 m thick section. In tandem with two ESR dating results, these zones can be reliably correlated with the geomagnetic polarity time scale (GPTS) from C3An.2r to C1n, and yield an age ranging from ∼7.0 Ma to ∼0.2 Ma. The long hiatus between the Mesozoic and the late Cenozoic, corresponding to the age of the basal conglomerates, suggests that uplift of the West Junggar Mt Range was initiated at least at ∼7.0 Ma ago. Furthermore, the onset of massive conglomerate deposits, as well as marked increases in sedimentation rate, k, T and Pj of AMS, occurred at ∼3.6 Ma. These notable changes are coeval with the peak deformation in Central Asia. Considering the depositional diachroneity of the Xiyu conglomerates and the predominantly dry climate in Central Asia since at least the late Cenozoic, we suggest that accelerated uplift of the West Junggar Mt Range at ∼3.6 Ma should be the main factor controlling these multiple changes within the Baiyanghe section. Another marked increase in conglomerate content, sedimentation rate and κ occurred at ∼1.1 Ma. The cause of this event deserves further investigation in the future.

  8. Phylogeny and biogeography of Primula sect. Armerina: implications for plant evolution under climate change and the uplift of the Qinghai-Tibet Plateau. (United States)

    Ren, Guangpeng; Conti, Elena; Salamin, Nicolas


    The historical orogenesis and associated climatic changes of mountain areas have been suggested to partly account for the occurrence of high levels of biodiversity and endemism. However, their effects on dispersal, differentiation and evolution of many groups of plants are still unknown. In this study, we examined the detailed diversification history of Primula sect. Armerina, and used biogeographic analysis and macro-evolutionary modeling to investigate a series of different questions concerning the evolution of the geographical and ecological distribution of the species in this section. We sequenced five chloroplast and one nuclear genes for species of Primula sect. Armerina. Neither chloroplast nor nuclear trees support the monophyly of the section. The major incongruences between the two trees occur among closely related species and may be explained by hybridization. Our dating analyses based on the chloroplast dataset suggest that this section began to diverge from its relatives around 3.55 million years ago, largely coinciding with the last major uplift of the Qinghai-Tibet Plateau (QTP). Biogeographic analysis supports the origin of the section in the Himalayan Mountains and dispersal from the Himalayas to Northeastern QTP, Western QTP and Hengduan Mountains. Furthermore, evolutionary models of ecological niches show that the two P. fasciculata clades have significantly different climatic niche optima and rates of niche evolution, indicating niche evolution under climatic changes and further providing evidence for explaining their biogeographic patterns. Our results support the hypothesis that geologic and climatic events play important roles in driving biological diversification of organisms in the QTP area. The Pliocene uplift of the QTP and following climatic changes most likely promoted both the inter- and intraspecific divergence of Primula sect. Armerina. This study also illustrates how niche evolution under climatic changes influences biogeographic

  9. 78 FR 46312 - Spruce Beetle Epidemic and Aspen Decline Management Response; Grand Mesa, Uncompahgre and... (United States)


    ... Colorado Plateau. It covers 3,161,900 acres across diverse vegetation ranging from sagebrush, pi on... may be used in high value areas. Aspen stands where less than 50% of the root system has been affected... Roadless Areas (CRAs), Research Natural Areas or Special Management Areas managed for Wilderness values...

  10. 77 FR 24673 - Grand Mesa, Uncompahgre and Gunnison National Forests; Colorado; Federal Coal Lease Modifications... (United States)


    ... temporary road construction and drilling of methane drainage wells. A Reasonably Foreseeable Mine Plan (RFMP... drainage well pads. Under the regulatory framework of the 2001 Roadless Area Conservation Rule, future road... proposed action deals primarily with underground mining. It is assumed that longwall mining practices would...

  11. Survey Data (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Cleaned and QCd data for the Fishing Effort Survey. Questions on fishing and other out are asked on weather and outdoor activity, including fishing trips. Used for...

  12. Surveying Humaness

    DEFF Research Database (Denmark)

    Markussen, Randi; Gad, Christopher

    and development of a large collection of biological and psychological symptoms and psycho-social problems. However, the surveys say nothing about how the information will be of use to the people who answer the procedure or how this scientific intervention will be put to use more specifically within the public......Christopher Gad. Ph.d. Dept. of Information and Media Studies Randi Markussen. Associate Professor, Dept. of Information and Media Studies.   Abstract:   Surveying humanness -politics of care improvement   For various reasons we both were subjected to a specific survey procedure...... carried out in a Danish county in order to improve treatment of people who have suffered from long-term illnesses. The surveys concern not only feed back on how people experience their present and past interaction with the social services and health care system; they also ask people to indicate the state...

  13. Surveying Humaness

    DEFF Research Database (Denmark)

    Markussen, Randi; Gad, Christopher

    carried out in a Danish county in order to improve treatment of people who have suffered from long-term illnesses. The surveys concern not only feed back on how people experience their present and past interaction with the social services and health care system; they also ask people to indicate the state...... and development of a large collection of biological and psychological symptoms and psycho-social problems. However, the surveys say nothing about how the information will be of use to the people who answer the procedure or how this scientific intervention will be put to use more specifically within the public......Christopher Gad. Ph.d. Dept. of Information and Media Studies Randi Markussen. Associate Professor, Dept. of Information and Media Studies.   Abstract:   Surveying humanness -politics of care improvement   For various reasons we both were subjected to a specific survey procedure...

  14. Analysis of Basin-Range Coupling Mechanisms during Epeirogenetic Uplift - A Case Study of Tectonic Coupling in the Songpan-Ganzi Plateau-Longmen Mountain-Sichuan Basin Region (United States)

    Ying, Danlin; Li, Ying


    The tectonodynamic evolution of the Songpan-Ganzi Plateau-Longmen Mountain-Sichuan basin region has been analyzed in this paper. The result suggested that the region had experienced principal four stages of evolution. The evolution was beginning with crystalline basement and folded basement formation in the pre-Sinian, then the cartonmarine sedimentary basin from the Sinian to the Middle Triassic was followed by uplift and stretching of the land from the Late Triassic to the Middle Jurassic, and finally compressive orogenesis since the Late Jurassic was happened. To understand the uplift and stretching of the land from the Late Triassic to the Middle Jurassic, a physical modeling experiment was conducted. It was confirmed that a tectonic plateau-ramp-basin geomorphology pattern developed during this period, caused by the wide difference in uplift between the Songpan-Ganzi Plateau and the Sichuan Basin. In the plateau region, the tectonic dynamic environment of uplift and stretching of the land (trailing edge extension) had appeared, which was accompany with the extensional structure styles such as normal faults and graben-horst structures. On the slope between the plateau and the basin, a bedding shear geodynamic environment was formed, and compressive slumped overthrust structure was found for the sliddown of decollement layers under the force of gravity. In the basin, compressive tectonic dynamic environment had emerged, which leaded to a compressive structure, such as thrust faults, overturned folds, and fault-related folds.

  15. Field demonstration of an active reservoir pressure management through fluid injection and displaced fluid extractions at the Rock Springs Uplift, a priority geologic CO2 storage site for Wyoming

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Zunsheng [Univ. of Wyoming, Laramie, WY (United States)


    This report provides the results from the project entitled Field Demonstration of Reservoir Pressure Management through Fluid Injection and Displaced Fluid Extraction at the Rock Springs Uplift, a Priority Geologic CO2 Storage Site for Wyoming (DE-FE0026159 for both original performance period (September 1, 2015 to August 31, 2016) and no-cost extension (September 1, 2016 to January 6, 2017)).

  16. Geometry and Kinematics of Thrust Tectonics of the Northern Longmenshan Mountains: Constraints for the Multi-phase Uplifting and Spreading of the Southeast Boundary of Qinghai-Tibet Plateau (United States)

    He, Dengfa; John, Suppe; chen, Longbo


    The Longmenshan Mountains thrust belt (LMSTB) is the southeastern boundary of the Qinghai-Tibetan plateau (QTP). To study its structural geometry and kinematics is of great significance to constrain the formation mechanism and evolution processes of the Qinghai-Tibetan plateau. Bounded by Guanxian and Anxian area, LMSTB is subdivided into three segments from SW to NE (i.e., the southern, middle and northern segment). The northern Longmenshan segment, lying around Anxian to Guangyuan area, is located at the southwestern end of the Qinling Orogenic Belt and the northeastern end of the Songpan-Ganzi folded belt, and is connected with the Bikou block and the Micangshan thrust belt at its northernmost part, which leads to a distinct superimposed tectonic setting for it. By employing the sandstone apatite fission track (AFT) and electron spin resonance (ESR), together with the study of regional unconformities and strata development, the paper analyzes the differential uplifting history and the uplifting migration processes in different area. Based on the surface geology, and the high resolution seismic profiles and drilling data, the fault arrays, the structural style and its variations in this area are studied and by balanced geological cross-section restoration, the kinematics with time of these faults is discussed. It shows that prior to the Late Triassic, the tectonic setting was extensional at the northern Longmenshan. Yet, at the early stage of the Late Triassic, it transited to be compressional and experienced tectonic inversion, which made the Upper Triassic Xujiahe Formation (T3x) lies above the Middle Triassic Leikoupo Formation (T2l) with a lower angular unconformity. When came to the end of the depositional period of the third member of T3x, the northern Longmenshan began to uplift regionally, which resulted in the lower-angular unconformities and disconformities between T3x3 and T3x4. At the end of the T3x, the northern Longmenshan experienced intensive

  17. Engineering surveying

    CERN Document Server

    Schofield, W


    Engineering surveying involves determining the position of natural and man-made features on or beneath the Earth's surface and utilizing these features in the planning, design and construction of works. It is a critical part of any engineering project. Without an accurate understanding of the size, shape and nature of the site the project risks expensive and time-consuming errors or even catastrophic failure.Engineering Surveying 6th edition covers all the basic principles and practice of this complex subject and the authors bring expertise and clarity. Previous editions of this classic text have given readers a clear understanding of fundamentals such as vertical control, distance, angles and position right through to the most modern technologies, and this fully updated edition continues that tradition.This sixth edition includes:* An introduction to geodesy to facilitate greater understanding of satellite systems* A fully updated chapter on GPS, GLONASS and GALILEO for satellite positioning in surveying* Al...

  18. An integrated study on microtectonics, geothermometry and thermochronology of the Çataldaǧ Core Complex (NW Turkey): Implications for cooling, deformation and uplift history (United States)

    Kamaci, Omer; Altunkaynak, Safak


    We present an integrated study on structure, microstructure, geothermometry and thermochronology of the Çataldaǧ Core Complex (ÇCC) in NW Turkey in order to understand the cooling, deformation and uplift mechanisms. ÇCC is formed from an Eo-Oligocene granite-gneiss-migmatite complex (GGMC) and an Early Miocene I-type granodioritic body (ÇG: Çataldaǧ granodiorite) which were exhumed as a dome-shaped core complex in the footwall of a ring-shaped low-angle detachment zone (The Çataldaǧ Detachment Fault Zone; ÇDFZ) in the Early Miocene. New U-Pb zircon (LA-ICPMS) and monazite ages of GGMC yielded magmatic ages of 33.8 and 30.1 Ma (Latest Eocene-Early Oligocene). 40Ar/39Ar muscovite, biotite and K-feldspar from the GGMC yielded the deformation age span 21.38±0,05 Ma and 20.81±0.04 Ma, which is also the emplacement age (20.84±0.13 Ma and 21.6±0.04 Ma) of ÇG. ÇDFZ is responsible for mainly top-to-the-north sense kinematic processes. The microstructural features of quartz, feldspar and mica indicate that the ÇCC has undergone continuous deformations during its cooling, from submagmatic to cataclastic conditions. Five microstructural grades have been classified under ductile (DZ) and ductile-to-brittle shear zone (SZ), according to the estimated deformation temperature and intensity of the strain. Microcline twinning, marginally replacement myrmekite and flame-perthite are predominant features for feldspar while chessboard extinction, grain boundary migration and subgrain rotation recrystallization is common for quartz in the DZ which has a deformation temperature range of >600°C to 400°C. Grain size reduction is an important factor for the ductile to brittle shear zone (SZ). Feldspar is represented by bulging recrystallization (BLG), feldspar-fish and domino-type microfracture/microfaulting and quartz show more elongated structures such as ribbons with high aspect ratios. Mineral-fish (muscovite, biotite and feldspar) structures indicate a temperature

  19. Surveying Education

    DEFF Research Database (Denmark)

    Enemark, Stig


    In relation to surveying education there is one big question to be asked: Is the role of the surveyors changing? In a global perspective the answer will be "Yes". There is a big swing that could be entitled "From Measurement to Management". This does not imply that measurement is no longer....... In surveying education there are a range of other challenges to be faced. These relate to the focus on learning to learn; the need for flexible curriculum to deal with constant change; the move towards introducing virtual academy; the demand for creating a quality culture; and the perspective of lifelong...... on an efficient interaction between education, research, and professional practice....

  20. Evidence for dextral transtensional development of the Rio Grande rift, from the Bear Mountains and the Lucero uplift, central New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Hayden, S.N. (Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Geology)


    Dextral faulting of late Eocene age associated with latest Laramide deformation has been noted for some time along the margins of, and adjacent to, the Rio Grande rift (RGr) in central NM. Recent mapping of the Hell's Mesa (HM) fault zone in the Bear Mountains and of the Comanche/Santa Fe fault zone along the western margin of the RGr at the Lucero uplift has constrained dextral deformation to extend into the Miocene, at least, and possibly into the Pliocene. The HM fault zone forms the eastern margin of the Mulligan Gulch graben between the Bear and Gallinas Mountains to the west. The main ridge of the Bear Mountains is structurally down-dropped by the HM fault and is part of the graben. This ridge is a topographic high, composed of interbedded rhyolitic ash-flow tuffs and basaltic andesite flows of the Oligocene to early Miocene Mogollon-Datil volcanic field, faulted against Eocene sediments of the Baca Formation, and Eocene to early Oligocene volcanic and volcaniclastic rocks of the Datil Group. The western margin of the RGr in the Albuquerque basin along the Lucero uplift, defined by the Comanche fault zone is structurally continuous with portions of the HM fault zone that make a right overstep through the down-dropped Navajo gap area at the southwest corner of the basin. The Comanche fault zone shows dextral-oblique shear geometry along an anastomosing zone of faulting up to 1 km wide. This zone has been intruded by hypabyssal basaltic rocks that have yielded a whole-rock K-Ar date of 27.1 Ma. In the Carrizo Arroyo (CA) area, slickenside lineations on these dikes show a strong dextral component of movement similar to that of the HM zone. The Santa Fe fault is a reverse fault for some distance north of CA. Motion on this fault has disrupted coarse sediments that contain clasts of the ca. 4.0 Ma Carrizo Mesa basalt. These observations are interpreted to indicate that dextral deformation has persisted at least through the earliest stage of extension.

  1. Determination of trapping pressure and temperature of petroleum inclusions using PVT simulation software - a case study of Lower Ordovician carbonates from the Lunnan Low Uplift, Tarim Basin

    Energy Technology Data Exchange (ETDEWEB)

    Liu, D.H.; Xiao, X.M.; Mi, J.K.; Li, X.Q.; Shen, J.K.; Song, Z.G.; Peng, P.A. [Chinese Academy of Sciences, Guangzhou (China). Guangzhou Institute of Geochemistry, State Key Laboratory of Organic Geochemistry


    We report a case study carried out on Lower Ordovician reservoir carbonates of the Lunnan Low Uplift, Tarim Basin, to determine trapping pressures and temperatures of petroleum inclusions from the intersection of isochores of coeval petroleum and aqueous fluid inclusions using PVT SIM software. There are four types of petroleum inclusions from this sequence. Their trapping pressures and temperatures are: Type I 80-105 {sup o}C, 199-230 bar; Type II 135-145 {sup o}C, 235-250 bar; Type III 155-165 {sup o}C, 344-360 bar, and Type IV 220-252 {sup o}C, 345-390 bar, respectively, which are consistently higher than their homogenization temperature and saturation pressures by about 5-15 {sup o}C and 25-70 bar. To confirm the reliability of the PVT simulation approach, fluid inclusions were synthesized in calcite under controlled temperature and pressure conditions and studied using the same methods. The calculated trapping pressure and temperature of the synthetic petroleum inclusions closely match the actual pressure and temperature applied in the experiment. By reference to the burial and geothermal history of the Tarim host rocks, it was inferred that Types I, II and III petroleum inclusions represent fluids associated with three distinct phases of petroleum emplacement in the Lower Ordovician strata of this area, occurring during late Silurian to early Devonian, Cretaceous to early Tertiary, and late Tertiary, respectively. Type IV petroleum inclusions occur only in some fine calcite veins from few samples, and are believed to be related to an anomalous thermal event in this area. On the basis of the trapping pressures and trapping temperatures of the petroleum inclusions, three main phases of the petroleum-filling of the Lower Ordovician reservoirs can be delineated. Phase I and Phase III petroleum events were related to petroleum migration and accumulation from the Lunnan Low Uplift or nearby area. The petroleum of the phase II petroleum event appears to have

  2. Constraints on timing and rates of strath terrace formation on actively uplifting anticlines in the foreland of the Chinese Tien Shan. (United States)

    Bufe, A.; Burbank, D. W.; Chen, J.; Liu, L.; Li, T.; Thompson, J. A.


    The formation of strath surfaces (fluvially created, sub-horizontal erosion surfaces) requires that the rate of lateral erosion outpaces the rate of incision of a river. The change from incision to strath cutting has commonly been linked to a decrease of incision rates due to shielding of the river bed by a thick sediment cover1. Straths are abandoned when the bed cover is reduced and incision resumes. A more recent study suggests that strath terrace formation might be linked to a change between a braided and a single-thread river2. Finally, several models have explored strath formation due to inherent dynamics of meandering systems3,4. In the foreland of the Tian Shan in northwest China, weakly consolidated Pliocene sand and siltstones are being actively uplifted at rates of 1 - 3 mm/y by a series of detachment anticlines. A number of elevated, several-kilometer-wide planation surfaces bear witness to a history of multiple strath cutting events by braided streams. In contrast, modern rivers incise into the uplifting folds creating 10 - 200 m deep canyons while the up- and downstream alluvial fans remain unincised. We use GIS analysis, field mapping, and OSL dating to describe incision and beveling of the folds. Our chronologic data reveal at least 2 - 3 beveling events over the last 40 ky on the Mutule fold. We find that lateral erosion of the bedrock during beveling events occurs at rates that are more than an order of magnitude higher than average incision rates. During times of incision (which can be tens of thousands of years long), lateral erosion rates need to be considerably lower in order to explain the formation of narrow canyons. Thus, our observations of scale, rate, and intermittency of strath cutting, seem difficult to reconcile with models that explain strath formation by variations of the incision rate1 or intrinsic meandering dynamics under steady forcing3,4. The critical requirement to explain our observations appears to be repeated changes in the

  3. Plio-Pleistocene paleo-erosion rates as a recorder of orographic barrier uplift in the NW-Argentine Andes (Humahuaca Basin) (United States)

    Pingel, Heiko; Schildgen, Taylor; Wittmann, Hella


    As an integral part of the Eastern Cordillera, the intermontane Humahuaca Basin in the NW Argentine Andes is located in transition between the arid and internally drained Puna Plateau to the west and the humid broken foreland to the east. In combination with moisture-bearing air masses sourced in the Atlantic Ocean and the Amazon Basin, the present-day topographic gradient of the eastern Andean margin comprises an efficient orographic barrier that results in a strong precipitation gradient, with rainfall of more than 2,000 mm/a along the eastern flanks and quartz-bearing fluvial sands and gravels of known stratigraphic age. In most cases, the age control is based on previously published U-Pb zircon data of intercalated volcanic ash deposits, but also utilizes new OSL and AMS14C ages. A reassessment of the sediment-accumulation history of the basin highlights important changes of the depositional system, apparently associated with the transformation from a humid foreland to a fluvially restricted and semi-arid intermontane basin. Similarly, our terrestrial cosmogenic nuclide-derived data indicate an order-of-magnitude decrease in erosion rates at ca. 3 Ma, which suggests a causal link between the onset of uplift-induced semi-arid conditions and decreasing sediment flux into the basin. Ultimately, this dataset may enable a systematic investigation of the long-term causes and consequences of orogenic growth and hydrological changes on spatio-temporal erosion patterns in active mountain areas.

  4. A Possible Source Mechanism of the 1946 Unimak Alaska Far-Field Tsunami: Uplift of the Mid-Slope Terrace Above a Splay Fault Zone (United States)

    von Huene, Roland; Miller, John J.; Klaeschen, Dirk; Dartnell, Peter


    In 1946, megathrust seismicity along the Unimak segment of the Alaska subduction zone generated the largest ever recorded Alaska/Aleutian tsunami. The tsunami severely damaged Pacific islands and coastal areas from Alaska to Antarctica. It is the charter member of "tsunami" earthquakes that produce outsized far-field tsunamis for the recorded magnitude. Its source mechanisms were unconstrained by observations because geophysical data for the Unimak segment were sparse and of low resolution. Reprocessing of legacy geophysical data reveals a deep water, high-angle reverse or splay thrust fault zone that leads megathrust slip upward to the mid-slope terrace seafloor rather than along the plate boundary toward the trench axis. Splay fault uplift elevates the outer mid-slope terrace and its inner area subsides. Multibeam bathymetry along the splay fault zone shows recent but undated seafloor disruption. The structural configuration of the nearby Semidi segment is similar to that of the Unimak segment, portending generation of a future large tsunami directed toward the US West coast.

  5. A possible source mechanism of the 1946 Unimak Alaska far-field tsunami, uplift of the mid-slope terrace above a splay fault zone (United States)

    von Huene, Roland E.; Miller, John J.; Klaeschen, Dirk; Dartnell, Peter


    In 1946, megathrust seismicity along the Unimak segment of the Alaska subduction zone generated the largest ever recorded Alaska/Aleutian tsunami. The tsunami severely damaged Pacific islands and coastal areas from Alaska to Antarctica. It is the charter member of “tsunami” earthquakes that produce outsized far-field tsunamis for the recorded magnitude. Its source mechanisms were unconstrained by observations because geophysical data for the Unimak segment were sparse and of low resolution. Reprocessing of legacy geophysical data reveals a deep water, high-angle reverse or splay thrust fault zone that leads megathrust slip upward to the mid-slope terrace seafloor rather than along the plate boundary toward the trench axis. Splay fault uplift elevates the outer mid-slope terrace and its inner area subsides. Multibeam bathymetry along the splay fault zone shows recent but undated seafloor disruption. The structural configuration of the nearby Semidi segment is similar to that of the Unimak segment, portending generation of a future large tsunami directed toward the US West coast.

  6. Restoration of the Cretaceous uplift of the Harz Mountains, North Germany: evidence for the geometry of a thick-skinned thrust (United States)

    Tanner, David C.; Krawczyk, Charlotte M.


    Reverse movement on the Harz Northern Boundary Fault was responsible for the Late Cretaceous uplift of the Harz Mountains in northern Germany. Using the known geometry of the surface position and dip of the fault, and a published cross section of the Base Permian horizon, we show that it is possible to predict the probable shape of the fault at depth, down to a detachment level. We use the `inclined-shear' method with constant heave and argue that a shear angle of 30° was most likely. In this case, the detachment level is at a depth of ca. 25 km. Kinematic restoration of the Harz Mountains using this fault geometry does not produce a flat horizon, rather it results in a ca. 4 km depression. Airy-Heiskanen isostatic equilibrium adjustment of the Harz Mountains restores the Base Permian horizon to the horizontal, as well as raising the Moho to a depth of 32 km, a typical value for northern Germany. Restoration also causes a rotation of tectonic fabrics within the Harz Mountains of about 11° clockwise. We show that this model geometry is very good fit to the interpreted DEKORP BASIN 9601 deep seismic profile.

  7. What Are Probability Surveys? (United States)

    The National Aquatic Resource Surveys (NARS) use probability-survey designs to assess the condition of the nation’s waters. In probability surveys (also known as sample-surveys or statistical surveys), sampling sites are selected randomly.

  8. Gravimetric survey and modeling of the basement morphology in the sedimentary thickness characterization, NE portion of Paraná Sedimentary Basin - Brazil

    Directory of Open Access Journals (Sweden)

    Maximilian Fries


    Full Text Available ABSTRACT: The northeast portion of the Paraná Sedimentary Basin is distinguished by structural highs as the known Pitanga Dome, an uplifted structure identified in the last century. It represents a geological and evolutionary evidence of the Paraná Sedimentary Basin and has undergone inspired studies and intense exploration surveys. This study consists of a gravimetric survey in the Pitanga Dome area, State of São Paulo, Brazil. The Bouguer gravity anomalies have been identified and related to the structural high, sedimentary thickness, and the basement morphology. Processing and enhancement techniques were used for forward modeling based on previous studies. The three models from profiles sectioning the dome have a sedimentary thickness varying from 200 to 1.250 meters. The adopted methodology has provided important results determining that the Pitanga Dome can be understood through rational 3D visualization. The area can be interpreted as an undulating basement with thinning of sedimentary rocks related to deep features (structures in the crust/mantle limit (Moho uplift. This characteristic is confirmed by the sedimentary layer thickening present throughout the surrounding area. The results also offer important insights and support for further studies concerning the genesis and evolution of this and other uplifted structures of the Paraná Sedimentary Basin.

  9. The River Mondego terraces at the Figueira da Foz coastal area (western central Portugal): Geomorphological and sedimentological characterization of a terrace staircase affected by differential uplift and glacio-eustasy

    DEFF Research Database (Denmark)

    Ramos, Anabela M.; Cunha, Pedro P.; Cunha, Lúcio. S.


    Mondego has incised into the Pliocene relief and its long drainage evolution is recorded within a series of inset river terrace landforms. These river terraces are better preserved on the right-hand (northern) bank, where they form a staircase developed against the uplifted Serra da Boa Viagem structure...... of active faults during the Quaternary. The main tectonic structure is the WNW–ESE trending Quiaios fault, responsible for the regional tilting towards SW. Other probably active faults and tectonic lineaments trend NNW–SSE to N–S, NNE–SSW to NE–SW and WNW–ESE. This study reports a long-term uplift rate of 0......-gravels and silts, but also some colluvium at the top of each terrace. The younger terraces (T3, T4 and T5) show better developed sedimentary structures and less sedimentary matrix; the sedimentary features are indicative of both fluvial and coastal environments (estuary and beach, as nowadays). Under conditions...

  10. Plio-Quaternary river incision rates inferred from burial dating (Al-26/Be-10) of in cave-deposited alluvium in the Meuse catchment (E Belgium): new insights into the uplift history of the Ardennes massif (United States)

    Rixhon, Gilles; Bourlès, Didier; Braucher, Régis; Peeters, Alexandre; Demoulin, Alain


    Although the Late Cenozoic uplift of the intraplate Variscan Ardennes/Rhenish massif (N Europe) has been long studied, its causes, shape and timing are still under debate (Demoulin & Hallot, 2009). This is mainly due to the scarcity of reliable ages for uplift markers, such as Quaternary terrace staircases along the deeply-incised valleys or Late Tertiary planation surfaces. In parallel, multi-level cave systems in limestone rocks, wherein abandoned phreatic passages filled with alluvium represent former phases of fluvial base-level stability, record the history of regional river incision (Anthony & Granger, 2007). Here, we present new burial ages (Al-26/Be-10) from fluvial gravels washed in a multi-level cave system developed in Devonian limestones of the lower Ourthe valley (main Ardennian tributary of the Meuse). Our results highlight a significant increase of incision rates from the Middle Pleistocene on, and allow reconstructing the incision history in the northern part of the Ardennes over the last 3.4 Ma. These long-term incision rates derived from burial ages are then discussed in relation to the existing studies dealing with river incision and/or tectonic uplift of the Ardennes/Rhenish massif (e.g. Demoulin & Hallot, 2009; Rixhon et al., 2011). Our cosmogenic nuclide ages thus enlarge the data pool required to explore the spatio-temporal characteristics of the drainage system's incision response to combined tectonic and climatic signals. References Anthony, D., Granger, D.E., 2007. A new chronology for the age of Appalachian erosional surfaces determined by cosmogenic nuclides in cave sediments. Earth Surf. Process. Landforms 32, 874-887 Demoulin, A., Hallot, E., 2009. Shape and amount of the Quaternary uplift of the western Rhenish shield and the Ardennes (western Europe). Tectonophysics 474, 696-708. Rixhon, G., et al., 2011. Quaternary river incision in NE Ardennes (Belgium): Insights from Be-10/Al-26 dating of rive terraces. Quaternary Geochronology 6

  11. Total Survey Error for Longitudinal Surveys

    NARCIS (Netherlands)

    Lynn, Peter; Lugtig, P.J.


    This article describes the application of the total survey error paradigm to longitudinal surveys. Several aspects of survey error, and of the interactions between different types of error, are distinct in the longitudinal survey context. Furthermore, error trade-off decisions in survey design and

  12. Delamination of lithospheric mantle evidenced by Cenozoic potassic rocks in Yunnan, SW China: A contribution to uplift of the Eastern Tibetan Plateau (United States)

    Chen, Bei; Long, Xiaoping; Wilde, Simon A.; Yuan, Chao; Wang, Qiang; Xia, Xiaoping; Zhang, Zhaofeng


    New zircon U-Pb ages, mineral chemical data, whole-rock geochemistry and Sr-Nd isotopes from the potassium-rich intrusions in the Yunnan area, SW China, were determined to provide constraints on the uplift of the Eastern Tibetan Plateau. The intrusive rocks consist of shoshonitic syenites (high-Mg syenites, low-Mg syenites and syenite porphyries) and potassic granitoids (granite porphyries). Zircon LA-ICP-MS U-Pb dating indicates coeval emplacement ages of 35 Ma. The shoshonitic syenites have alkaline affinities and the enrichment in LILEs and LREEs (e.g. La, Sr, U, Pb), with depletion of HFSEs (e.g. Nb, Ti, Ta) and weak Eu anomalies. They display uniform Sr-Nd-Lu-Hf isotopic compositions with similar initial 87Sr/86Sr ratios (0.7073-0.7079), enriched εNd(t) values (- 6.8 to - 4.3) and mostly negative zircon εHf(t) values ranging from - 4.6 to + 0.1. The high-Mg syenites have high MgO, Fe2O3T, TiO2, CaO, Cr, Ni concentrations and relatively high Mg# (60-68), indicating an origin from enriched lithospheric mantle. The low-Mg syenites and syenite porphyries are geochemically distinct with the high-Mg syenites, but the insignificant variations in major elements, linear trends of La against (La/Yb)N and similar Sr-Nd isotopic compositions to the high-Mg syenites suggest that they were produced by different degrees of partial melting of the same enriched mantle source. The potassic granitic intrusions are sub-alkaline with a strongly peraluminous character. They display an S-type granite affinity, with high Al2O3/TiO2 and low CaO/Na2O and K2O/Al2O3 ratios, suggesting a pelitic source. They are LREE-enriched and have relatively flat HREE patterns with weakly negative Eu anomalies and positive Rb, U, and Pb anomalies and negative Nb, Ta, and Ti anomalies. They have relatively high initial 87Sr/86Sr ratios (0.7143) and enriched Nd isotopic compositions [εNd(t) = - 4.1]. Their zircon εHf(t) values (- 4.0 to + 0.09) and old two-stage Hf model ages (TDMc = 1.16-1.36 Ga

  13. Multiple Surveys of Students and Survey Fatigue (United States)

    Porter, Stephen R.; Whitcomb, Michael E.; Weitzer, William H.


    This chapter reviews the literature on survey fatigue and summarizes a research project that indicates that administering multiple surveys in one academic year can significantly suppress response rates in later surveys. (Contains 4 tables.)

  14. Polyphase exhumation in the western Qinling Mountains, China: Rapid Early Cretaceous cooling along a lithospheric-scale tear fault and pulsed Cenozoic uplift. (United States)

    Heberer, Bianca; Anzenbacher, Thomas; Neubauer, Franz; Genser, Johann; Dong, Yunpeng; Dunkl, István


    The western sector of the Qinling-Dabie orogenic belt plays a key role in both Late Jurassic to Early Cretaceous "Yanshanian" intracontinental tectonics and Cenozoic lateral escape triggered by India-Asia collision. The Taibai granite in the northern Qinling Mountains is located at the westernmost tip of a Yanshanian granite belt. It consists of multiple intrusions, constrained by new Late Jurassic and Early Cretaceous U-Pb zircon ages (156 ± 3 Ma and 124 ± 1 Ma). Applying various geochronometers ( 40 Ar/ 39 Ar on hornblende, biotite and K-feldspar, apatite fission-track, apatite [U-Th-Sm]/He) along a vertical profile of the Taibai Mountain refines the cooling and exhumation history. The new age constraints record the prolonged pre-Cenozoic intracontinental deformation as well as the cooling history mostly related to India-Asia collision. We detected rapid cooling for the Taibai granite from ca. 800 to 100 °C during Early Cretaceous (ca. 123 to 100 Ma) followed by a period of slow cooling from ca. 100 Ma to ca. 25 Ma, and pulsed exhumation of the low-relief Cretaceous peneplain during Cenozoic times. We interpret the Early Cretaceous rapid cooling and exhumation as a result from activity along the southern sinistral lithospheric scale tear fault of the recently postulated intracontinental subduction of the Archean/Palaeoproterozoic North China Block beneath the Alashan Block. A Late Oligocene to Early Miocene cooling phase might be triggered either by the lateral motion during India-Asia collision and/or the Pacific subduction zone. Late Miocene intensified cooling is ascribed to uplift of the Tibetan Plateau.

  15. Post-Triassic thermal history of the Tazhong Uplift Zone in the Tarim Basin, Northwest China: Evidence from apatite fission-track thermochronology

    Directory of Open Access Journals (Sweden)

    Caifu Xiang


    Full Text Available The Tarim Basin is a representative example of the basins developed in the northwest China that are characterized by multiple stages of heating and cooling. In order to better understand its complex thermal history, apatite fission track (AFT thermochronology was applied to borehole samples from the Tazhong Uplift Zone (TUZ. Twelve sedimentary samples of Silurian to Triassic depositional ages were analyzed from depths coinciding with the apatite partial annealing zone (∼60–120 °C. The AFT ages, ranging from 132 ± 7 Ma (from a Triassic sample to 25 ± 2 Ma (from a Carboniferous sample, are clearly younger than their depositional ages and demonstrate a total resetting of the AFT thermometer after deposition. The AFT ages vary among different tectonic belts and decrease from the No. Ten Faulted Zone (133–105 Ma in the northwest, the Central Horst Zone in the middle (108–37 Ma, to the East Buried Hill Zone in the south (51–25 Ma. Given the low magnitude of post-Triassic burial heating evidenced by low vitrinite reflectance values (Ro < 0.7%, the total resetting of the AFT system is speculated to result from the hot fluid flow along the faults. Thermal effects along the faults are well documented by younger AFT ages and unimodal single grain age distributions in the vicinity of the faults. Permian–early Triassic basaltic volcanism may be responsible for the early Triassic total annealing of those samples lacking connectivity with the fault. The above arguments are supported by thermal modeling results.

  16. Survey research. (United States)

    Krosnick, J A


    For the first time in decades, conventional wisdom about survey methodology is being challenged on many fronts. The insights gained can not only help psychologists do their research better but also provide useful insights into the basics of social interaction and cognition. This chapter reviews some of the many recent advances in the literature, including the following: New findings challenge a long-standing prejudice against studies with low response rates; innovative techniques for pretesting questionnaires offer opportunities for improving measurement validity; surprising effects of the verbal labels put on rating scale points have been identified, suggesting optimal approaches to scale labeling; respondents interpret questions on the basis of the norms of everyday conversation, so violations of those conventions introduce error; some measurement error thought to have been attributable to social desirability response bias now appears to be due to other factors instead, thus encouraging different approaches to fixing such problems; and a new theory of satisficing in questionnaire responding offers parsimonious explanations for a range of response patterns long recognized by psychologists and survey researchers but previously not well understood.

  17. Areas of Active Tectonic Uplift Are Sensitive to Small Changes in Fold Orientations within a Broad Zone of Left-lateral Transpression and Shearing, Dominican Republic and Haiti (Hispaniola) (United States)

    Ambrosius, I.; Mann, P.


    Previous GPS studies have shown that the island of Hispaniola is a 250 km-wide zone of active, east-west, left-lateral shearing along two major strike-slip zones: the Septentrional-Oriente fault zone through the northern part of the island and the Enriquillo-Plantain Garden fault zone (EPGFZ) through the southern part of the island. The total interplate rate distributed on both faults is 21 mm/yr. Using a high-resolution DEM, we constructed fluvial channel profiles across transpression-related folds of late Miocene to recent age in the area of central and southern Dominican Republic and Haiti to determine controls of areas of relatively high, moderate, and slow uplift inferred from fluvial channel profiles. Fold axes in this area extend for 50-150 km and exhibit two different trends: 1) folds that occupy the area of the Sierra de Neiba-Chaine des Matheux north of the Enriquillo-Cul-de-Sac Valley and EPGFZ and folds that occupy the area of the Sierra de Bahoruco-Massif de la Selle all exhibit more east-west fold axes trending 110; 2) folds that occupy the area northwest of the EPGFZ in the western Chaine des Matheux and Sierra de Neiba all exhibit fold axes with more northwest trends of 125. River channel profiles show that the second group of more northwesterly-trending fold axes show relatively higher rates of tectonic uplift based on their convex-upward river profiles. Our interpretation for regional variations in river profiles and inferred uplift is that uplift is more pronounced on fold axes trending 15 degrees more to the northwest because their axes are more oblique to the interplate direction of east-west shearing. Longterm uplift rates previously measured from a stairstep of late Quaternary coral terraces at the plunging nose of the westernmost Chaine des Matheux have been previously shown to be occurring at a rate of 0.19 mm/yr. Onland exposures of Holocene corals are found only on one locality within the southern area of folds 30 km west of the epicenter

  18. An Improved Source Model for the Mw 7.1, October 23, 2011 Van (Turkey) Earthquake: New Insights from SAR Pixel Offsets and Coastal Uplift Measurements (United States)

    Akoglu, Ahmet M.; Jónsson, Sigurjón; Çakır, Ziyadin; Ergintav, Semih; Uǧur, Doǧan; Wang, Teng; Osmanoǧlu, Batuhan; Feng, Guangcai; Zabcı, Cengiz; Emre, Ömer


    The October 23rd, 2011, Mw 7.1, Van earthquake is the largest instrumentally recorded thrust faulting event in Turkey. The absence of a clear prominent surface rupture also marks this earthquake as the most recent case of blind faulting in the country. The Van earthquake has already been extensively studied by many researchers, with many of them relying only on the available InSAR data. However, due to limited coherence and data coverage and also due to the fact that the available coseismic data came only from descending satellite orbits, it proved difficult to constrain the parameters of the causative fault. Pixel offsets calculated in the flight (azimuth) and range directions are byproducts of SAR imaging and can provide a secondary perspective of the surface displacements when accurate. With the introduction of high resolution X-band SAR satellites it became possible to benefit more from the pixel offset information due to the increase in accuracy. We use offset information from a raw Cosmo-SkyMed SAR image pair, where the slave image was acquired only 4 hours after the October, 23rd, 2011 Van (Turkey) earthquake, which enables us to extend the coverage and to minimize the contribution of postseismic motion after the event. The pixel offsets are calculated using a novel technique that only considers reliable point-like scatterers for the offset measurements to increase their accuracy. The introduction of this new dataset helped us to minimize unwrapping errors due to loss of coherence around the surface projection of the causative fault, which the amplitude information is independent of. In addition to SAR pixel offsets, we also incorporate a new set of measurements of the uplift along the Lake Van coast due to the earthquake using dead algae levels as biological markers. Although sparse, these measurements were crucial to improve our final source model of the earthquake since the InSAR measurements only provide the relative displacement between two points on

  19. Tectonic uplift-influenced monsoonal changes promoted hominin occupation of the Luonan Basin: Insights from a loess-paleosol sequence, eastern Qinling Mountains, central China (United States)

    Fang, Qian; Hong, Hanlie; Zhao, Lulu; Furnes, Harald; Lu, Huayu; Han, Wen; Liu, Yao; Jia, Zhuoyue; Wang, Chaowen; Yin, Ke; Algeo, Thomas J.


    Quaternary soil deposits from northern and southern China are distinctly different, reflecting variability of the East Asian monsoon north and south of the Qinling Mountains. Coeval sediments from the transitional climatic zone of central China, which are little studied to date, have the potential to improve our understanding of Quaternary monsoon changes and associated influences on hominin occupation of this region. Here, we investigate in detail a well-preserved and continuous Quaternary loess-paleosol sequence (Shangbaichuan) from the Luonan Basin, using a variety of weathering indices including major and trace element ratios, clay mineralogy, and Fe-oxide mineralogy. The whole-rock samples display similar rare earth element patterns characterized by upper continental crustal ratios: (La/Yb)N ≈ 9.5 and Eu/Eu* ≈ 0.65. Elemental data such as (La/Yb)N, La/Th and Eu/Eu* ratios show a high degree of homogeneity, suggesting that dust in the source region may have been thoroughly mixed and recycled, resulting in all samples having a uniform initial composition. Indices for pedogenic weathering such as Na/K, Ba/Sr, Rb/Sr, CIA, CIW, CPA, PIA, kaolinite/illite, (kaolinite + smectite)/illite, and hematite/(hematite + goethite) exhibit similar secular trends and reveal a four-stage accumulation history. The indices also indicate that the climate was warmer and wetter during the most recent interglacial stage, compared with coeval environments of the Chinese Loess Plateau. Secular changes in weathering intensity can be related to stepwise uplift of the Qinling Mountains and variation in East Asian monsoon intensity, both of which played significant roles in controlling climate evolution in the Luonan Basin. Furthermore, intensified aridity and winter monsoon strength in dust source areas, as evidenced by mineralogic and geochemical changes, may have been due to the mid-Pleistocene climate transition. Based on temporal correlation of warmer and wetter climatic conditions

  20. The Two Subduction Zones of the Southern Caribbean: Lithosphere Tearing and Continental Margin Recycling in the East, Flat Slab Subduction and Laramide-Style Uplifts in the West (United States)

    Levander, A.; Bezada, M. J.; Niu, F.; Schmitz, M.


    The southern Caribbean plate boundary is a complex strike-slip fault system bounded by oppositely vergent subduction zones, the Antilles subduction zone in the east, and a currently locked Caribbean-South American subduction zone in the west (Bilham and Mencin, 2013). Finite-frequency teleseismic P-wave tomography images both the Atlanic (ATL) and the Caribbean (CAR) plates subducting steeply in opposite directions to transition zone depths under northern South America. Ps receiver functions show a depressed 660 discontinuity and thickened transition zone associated with each subducting plate. In the east the oceanic (ATL) part of the South American (SA) plate subducts westward beneath the CAR, initiating the El Pilar-San Sebastian strike slip system, a subduction-transform edge propagator (STEP) fault (Govers and Wortel, 2005). The point at which the ATL tears away from SA as it descends into the mantle is evidenced by the Paria cluster seismicity at depths of 60-110 km (Russo et al, 1993). Body wave tomography and lithosphere-asthenosphere boundary (LAB) thickness determined from Sp and Ps receiver functions and Rayleigh waves suggest that the descending ATL also viscously removes the bottom third to half of the SA continental margin lithospheric mantle as it descends. This has left thinned continental lithosphere under northern SA in the wake of the eastward migrating Antilles subduction zone. The thinned lithosphere occupies ~70% of the length of the El Pilar-San Sebastian fault system, from ~64oW to ~69oW, and extends inland several hundred kilometers. In northwestern SA the CAR subducts east-southeast at low angle under northern Colombia and western Venezuela. The subducting CAR is at least 200 km wide, extending from northernmost Colombia as far south as the Bucaramanga nest seismicity. The CAR descends steeply under Lake Maracaibo and the Merida Andes. This flat slab is associated with three Neogene basement cored, Laramide-style uplifts: the Santa Marta

  1. Nutrient uplift in a cyclonic eddy increases diversity, primary productivity and iron demand of microbial communities relative to a western boundary current

    Directory of Open Access Journals (Sweden)

    Martina A. Doblin


    Full Text Available The intensification of western boundary currents in the global ocean will potentially influence meso-scale eddy generation, and redistribute microbes and their associated ecological and biogeochemical functions. To understand eddy-induced changes in microbial community composition as well as how they control growth, we targeted the East Australian Current (EAC region to sample microbes in a cyclonic (cold-core eddy (CCE and the adjacent EAC. Phototrophic and diazotrophic microbes were more diverse (2–10 times greater Shannon index in the CCE relative to the EAC, and the cell size distribution in the CCE was dominated (67% by larger micro-plankton $(\\geq 20\\lrm{\\mu }\\mathrm{m}$ ≥ 20 μ m , as opposed to pico- and nano-sized cells in the EAC. Nutrient addition experiments determined that nitrogen was the principal nutrient limiting growth in the EAC, while iron was a secondary limiting nutrient in the CCE. Among the diazotrophic community, heterotrophic NifH gene sequences dominated in the EAC and were attributable to members of the gamma-, beta-, and delta-proteobacteria, while the CCE contained both phototrophic and heterotrophic diazotrophs, including Trichodesmium, UCYN-A and gamma-proteobacteria. Daily sampling of incubation bottles following nutrient amendment captured a cascade of effects at the cellular, population and community level, indicating taxon-specific differences in the speed of response of microbes to nutrient supply. Nitrogen addition to the CCE community increased picoeukaryote chlorophyll a quotas within 24 h, suggesting that nutrient uplift by eddies causes a ‘greening’ effect as well as an increase in phytoplankton biomass. After three days in both the EAC and CCE, diatoms increased in abundance with macronutrient (N, P, Si and iron amendment, whereas haptophytes and phototrophic dinoflagellates declined. Our results indicate that cyclonic eddies increase delivery of nitrogen to the upper ocean to potentially

  2. Surveying the Alentejo continental shelf for minerals and Quaternary environmental changes: preliminary results of the MINEPLAT project survey (United States)

    Noiva, João; Ribeiro, Carlos; Terrinha, Pedro; Brito, Pedro; Neres, Marta


    The tectonic uplift of South Portugal in the last 5 Million years (My) was firstly identified on the basis of morphologic criteria by Mariano Feio (1952, "The evolution of the relief of Baixo Alentejo and Algarve", transl.). However, the assessment of continental vertical movements off Portugal and its relation with tectonics was only initiated in the 1990-ies. This work was carried out in the framework of FP6 and FP7 in the domains of Natural Hazards funded by the European Community. The swath bathymetry cartography of the southwest part of the Iberian Peninsula resulted from the effort of European and national projects, of 19 oceanographic surveys, a total of 200 ship time days executed from 2000 to 2006, involving 14 research institutions from 7 European countries. As a result of this effort together with acquisition and interpretation of thousands of km of seismic reflection profiles, the Pliocene-Quaternary uplift of the Alentejo continental margin (SW Portugal) is now widely accepted by the scientific community. This uplift has not been yet quantified but it is possible that can have contributed to erosion and deposition of metallic ores as placers in the continental shelf. This argues in favor of the potential existence of placers in the continental shelf and the need for the detailed investigation that will allow determination of ideal location for placers deposition in the past Pliocene-Quaternary (5 My). The source for metals can arguably be associated to the Iberian Pyrite Belt ores hosted in the Alentejo Paleozoic formations and to the hyper-alkaline intrusions of Sines and Monchique of Late Cretaceous age. Artificial renourishment of beaches with offshore sand has not been assessed for the Alentejo littoral, despite that the coast located to the south of the Sines segment shows high susceptibility to erosion. This has been observed on a regular basis as the beaches are frequently devoid of sand, thus jeopardizing their touristic potential. The detailed

  3. Is the track of the Yellowstone hotspot driven by a deep mantle plume? - Review of volcanism, faulting, and uplift in light of new data (United States)

    Pierce, K.L.; Morgan, L.A.


    .5??Ma) "large volume (> 7000??km3)", and high temperature rhyolitic eruptions (> 1000????C) along a ~ 200-km-wide east-west band. The broad transition area required a heat source of comparable area. Differing characteristics of the volcanic fields here may in part be due to variations in crustal composition but also may reflect development in differing parts of an evolving plume where the older fields may reflect the eruption from several volcanic centers located above very large and extensive rhyolitic magma chamber(s) over the detached plume head while the younger fields may signal the arrival of the plume tail intercepting and melting the lithosphere and generating a more focused rhyolitic magma chamber. The three youngest volcanic fields of the hotspot track started with large ignimbrite eruptions at 10.21, 6.62, and 2.05??Ma. They indicate hotspot migration N55?? E at ~ 25??km/m.y. compatible in direction and velocity with the North American Plate motion. The Yellowstone Crescent of High Terrain (YCHT) flares outward ahead of the volcanic progression in a pattern similar to a bow-wave, and thus favors a sub-lithospheric driver. Estimates of YCHT-uplift rates are between 0.1 and 0.4??mm/yr. Drainage divides have migrated northeastward with the hotspot. The Continental Divide and a radial drainage pattern now centers on the hotspot. The largest geoid anomaly in the conterminous U.S. is also centered on Yellowstone and, consistent with uplift above a mantle plume. Bands of late Cenozoic faulting extend south and west from Yellowstone. These bands are subdivided into belts based both on recency of offset and range-front height. Fault history within these belts suggests the following pattern: Belt I - starting activity but little accumulated offset; Belt II - peak activity with high total offset and activity younger than 14??ka; Belt III - waning activity with large offset and activity younger than 140??ka; and Belt IV - apparently dead on substanti

  4. Simulated variations of eolian dust from inner Asian deserts at the mid-Pliocene, last glacial maximum, and present day: contributions from the regional tectonic uplift and global climate change

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Zhengguo; Liu, Xiaodong; An, Zhisheng [Chinese Academy of Sciences, State Key Laboratory of Loess Quaternary Geology (SKLLQG), Institute of Earth Environment, Xi' an (China); Yi, Bingqi; Yang, Ping [Texas A and M University, College Station, TX (United States); Mahowald, Natalie [Cornell University, Ithaca, NY (United States)


    Northern Tibetan Plateau uplift and global climate change are regarded as two important factors responsible for a remarkable increase in dust concentration originating from inner Asian deserts during the Pliocene-Pleistocene period. Dust cycles during the mid-Pliocene, last glacial maximum (LGM), and present day are simulated with a global climate model, based on reconstructed dust source scenarios, to evaluate the relative contributions of the two factors to the increment of dust sedimentation fluxes. In the focused downwind regions of the Chinese Loess Plateau/North Pacific, the model generally produces a light eolian dust mass accumulation rate (MAR) of 7.1/0.28 g/cm{sup 2}/kyr during the mid-Pliocene, a heavier MAR of 11.6/0.87 g/cm{sup 2}/kyr at present, and the heaviest MAR of 24.5/1.15 g/cm{sup 2}/kyr during the LGM. Our results are in good agreement with marine and terrestrial observations. These MAR increases can be attributed to both regional tectonic uplift and global climate change. Comparatively, the climatic factors, including the ice sheet and sea surface temperature changes, have modulated the regional surface wind field and controlled the intensity of sedimentation flux over the Loess Plateau. The impact of the Tibetan Plateau uplift, which increased the areas of inland deserts, is more important over the North Pacific. The dust MAR has been widely used in previous studies as an indicator of inland Asian aridity; however, based on the present results, the interpretation needs to be considered with greater caution that the MAR is actually not only controlled by the source areas but the surface wind velocity. (orig.)

  5. Occurrence of 1 ka-old corals on an uplifted reef terrace in west Luzon, Philippines: Implications for a prehistoric extreme wave event in the South China Sea region (United States)

    Ramos, Noelynna T.; Maxwell, Kathrine V.; Tsutsumi, Hiroyuki; Chou, Yu-Chen; Duan, Fucai; Shen, Chuan-Chou; Satake, Kenji


    Recent 230Th dating of fossil corals in west Luzon has provided new insights on the emergence of late Quaternary marine terraces that fringe west Luzon Island facing the Manila Trench. Apart from regional sea level changes, accumulated uplift from aseismic and seismic processes may have influenced the emergence of sea level indicators such as coral terraces and notches. Varied elevations of middle-to-late Holocene coral terraces along the west Luzon coasts reveal the differential uplift that is probably associated with the movement of local onland faults or upper-plate structures across the Manila Trench forearc basin. In Badoc Island, offshore west of Luzon mainland, we found notably young fossil corals, dated at 945.1 ± 4.6 years BP and 903.1 ± 3.9 years BP, on top of a 5-m-high reef platform. To constrain the mechanism of emergence or emplacement of these fossil corals, we use field geomorphic data and wave inundation models to constrain an extreme wave event that affected west Luzon about 1000 years ago. Our preliminary tectonic and tsunami models show that a megathrust rupture will likely lead to subsidence of a large part of the west Luzon coast, while permanent coastal uplift is attributed to an offshore upper-plate rupture in the northern Manila Trench forearc region. The modeled source fault ruptures and tsunami lead to a maximum wave height of more than 3 m and inundation distance as far as 2 km along the coasts of western and northern Luzon. While emplacement of coral boulders by an unusually strong typhoon is also likely, modeled storm surge heights along west Luzon do not exceed 2 m even with Typhoon Haiyan characteristics. Whether tsunami or unusually strong typhoon, the occurrence of a prehistoric extreme wave event in west Luzon remains an important issue in future studies of coastal hazards in the South China Sea region.

  6. Alumni Perspectives Survey, 2010. Survey Report (United States)

    Sheikh, Sabeen


    During the months of April and September of 2009, the Graduate Management Admission Council[R] (GMAC[R]) conducted the Alumni Perspectives Survey, a longitudinal study of prior respondents to the Global Management Education Graduate Survey of management students nearing graduation. A total of 3,708 alumni responded to the April 2009 survey,…

  7. Paleogeography and paleoenvironments of southwestern Baffin Island (Nunavut, Canada): post-glacial isostatic uplift and isolation of Nettilling Lake from marine influence (United States)

    Narancic, Biljana; Pienitz, Reinhard; Francus, Pierre; Rolland, Nicolas; Wagner, Anne-Marie


    Although signs of recent climate change are more compelling in circumpolar regions, we have limited knowledge of Arctic climates and environments and their past variability. In order to better understand and anticipate the extent and nature of future changes in the Arctic, it is necessary to increase our capacity to model past environmental changes. Instrumental monitoring using high technology in polar regions has been implemented only over recent decades (Pienitz et al., 2004). Hence, to extend in time the climate record, we use a multi-proxy paleolimnological approach to study the sedimentary records preserved in Nettilling Lake located on Baffin Island the largest lake in the Canadian Arctic Archipelago. Nettilling Lake has an area of 5.541 km2 and a maximum depth of 65 m (Oliver, 1964). Its basin has undergone postglacial marine invasion following the last deglaciation due to isostatic subsidence exerted by the Laurentide Ice Sheet. The glacio-isostatic uplift of the region resulted in the establishment of a freshwater lake around 5000 years BP (Jacobs et al., 1997). Nettilling Lake remains a scientific frontier for researchers, mainly due to the inaccessibility of the area and the lack of available data. To date, only one exploratory study by Oliver (1964) has focused on the limnological conditions and bathymetry of the lake, and our research aims at providing deeper insights into the history of paleoenvironmental changes in this remote Arctic region. Biostratigraphical and geochemical analyses were completed on two sediment cores, one from a lagoonal system in the northwestern part of Nettilling Lake and another from the eastern part of the Lake. The sediment cores from the lagoonal system clearly document the marine-lacustrine transition through shifts in paleosalinity inferred from the composition of fossil diatom assemblages. Fossil chironomid larvae first appeared in the record after basin isolation and the establishment of freshwater conditions. Precise

  8. Optimizing accuracy of determinations of CO₂ storage capacity and permanence, and designing more efficient storage operations: An example from the Rock Springs Uplift, Wyoming

    Energy Technology Data Exchange (ETDEWEB)

    Bentley, Ramsey [Univ. of Wyoming, Laramie, WY (United States). Dept. of Chemistry; Dahl, Shanna [Univ. of Wyoming, Laramie, WY (United States). Dept. of Chemistry; Deiss, Allory [Univ. of Wyoming, Laramie, WY (United States). Dept. of Chemistry; Duguid, Andrew [Univ. of Wyoming, Laramie, WY (United States). Dept. of Chemistry; Ganshin, Yuri [Univ. of Wyoming, Laramie, WY (United States). Dept. of Chemistry; Jiao, Zunsheng [Univ. of Wyoming, Laramie, WY (United States). Dept. of Chemistry; Quillinan, Scott [Univ. of Wyoming, Laramie, WY (United States). Dept. of Chemistry


    At a potential injection site on the Rock Springs Uplift in southwest Wyoming, an investigation of confining layers was undertaken to develop and test methodology, identify key data requirements, assess previous injection scenarios relative to detailed confining layer properties, and integrate all findings in order to reduce the uncertainty of CO₂ storage permanence. The assurance of safe and permanent storage of CO₂ at a storage site involves a detailed evaluation of the confining layers. Four suites of field data were recognized as crucial for determining storage permanence relative to the confining layers; seismic, core and petrophysical data from a wellbore, formation fluid samples, and in-situ formation tests. Core and petrophysical data were used to create a vertical heterogenic property model that defined porosity, permeability, displacement pressure, geomechanical strengths, and diagenetic history. These analyses identified four primary confining layers and multiple redundant confining layers. In-situ formation tests were used to evaluate fracture gradients, regional stress fields, baseline microseismic data, step-rate injection tests, and formation perforation responses. Seismic attributes, correlated with the vertical heterogenic property models, were calculated and used to create a 3-D volume model over the entire site. The seismic data provided the vehicle to transform the vertical heterogenic property model into a horizontal heterogenic property model, which allowed for the evaluation of confining layers across the entire study site without risking additional wellbore perforations. Lastly, formation fluids were collected and analyzed for geochemical and isotopic compositions from stacked reservoir systems. These data further tested primary confining layers, by evaluating the evidence of mixing between target reservoirs (mixing would imply an existing breach of primary confining layers). All data were propagated into a dynamic, heterogenic geologic

  9. Lesotho - Enterprise Survey (United States)

    Millennium Challenge Corporation — The 2011 MCA-Lesotho baseline enterprise survey is a national survey of enterprises. The main objective of the survey was to assess the current status of businesses...

  10. Determination of Cenozoic sedimentary structures using integrated geophysical surveys: A case study in the Barkol Basin, Xinjiang, China (United States)

    Sun, Kai; Chen, Chao; Du, Jinsong; Wang, Limin; Lei, Binhua


    Thickness estimation of sedimentary basin is a complex geological problem, especially in an orogenic environment. Intense and multiple tectonic movements and climate changes result in inhomogeneity of sedimentary layers and basement configurations, which making sedimentary structure modelling difficult. In this study, integrated geophysical methods, including gravity, magnetotelluric (MT) sounding and electrical resistivity tomography (ERT), were used to estimate basement relief to understand the geological structure and evolution of the eastern Barkol Basin in China. This basin formed with the uplift of the eastern Tianshan during the Cenozoic. Gravity anomaly map revealed the framework of the entire area, and ERT as well as MT sections reflected the geoelectric features of the Cenozoic two-layer distribution. Therefore, gravity data, constrained by MT, ERT and boreholes, were utilized to estimate the spatial distribution of the Quaternary layer. The gravity effect of the Quaternary layer related to the Tertiary layer was later subtracted to obtain the residual anomaly for inversion. For the Tertiary layer, the study area was divided into several parts because of lateral difference of density contrasts. Gravity data were interpreted to determine the density contrast constrained by the MT results. The basement relief can be verified by geological investigation, including the uplift process and regional tectonic setting. The agreement between geophysical survey and prior information from geology emphasizes the importance of integrated geophysical survey as a complementary means of geological studies in this region.

  11. Gas Hydrate Occurrence Inferred from Dissolved Cl− Concentrations and δ18O Values of Pore Water and Dissolved Sulfate in the Shallow Sediments of the Pockmark Field in Southwestern Xisha Uplift, Northern South China Sea

    Directory of Open Access Journals (Sweden)

    Min Luo


    Full Text Available Deep-water pockmarks are frequently accompanied by the occurrence of massive gas hydrates in shallow sediments. A decline in pore-water Cl− concentration and rise in δ18O value provide compelling evidence for the gas hydrate dissociation. Mega-pockmarks are widely scattered in the southwestern Xisha Uplift, northern South China Sea (SCS. Pore water collected from a gravity-core inside of a mega-pockmark exhibits a downward Cl− concentration decrease concomitant with an increase in δ18O value at the interval of 5.7–6.7 mbsf. Concentrations of Cl−, Na+, and K+ mainly cluster along the seawater freshening line without distinct Na+ enrichment and K+ depletion. Thus, we infer that the pore water anomalies of Cl− concentrations and δ18O values are attributed to gas hydrate dissociation instead of clay mineral dehydration. Moreover, the lower δ18O values of sulfate in the target core (C14 than those in the reference core (C9 may be associated with the equilibrium oxygen fractionation during sulfate reduction between sulfate and the relatively 18O-depleted ambient water resulting from gas hydrate formation. The gas hydrate contents are estimated to be 6%–10% and 7%–15%, respectively, according to the offset of Cl− concentrations and δ18O values from the baselines. This pockmark field in southwestern Xisha Uplift is likely to be a good prospective area for the occurrence of gas hydrate in shallow sediments.

  12. Handbook of web surveys

    NARCIS (Netherlands)

    Bethlehem, J.; Biffignandi, S.


    Best practices to create and implementhighly effective web surveys Exclusively combining design and sampling issues, Handbook of Web Surveys presents a theoretical yet practical approach to creating and conducting web surveys. From the history of web surveys to various modes of data collection to

  13. Radio Surveys: an Overview

    NARCIS (Netherlands)

    Morganti, Raffaella

    Radio astronomy has provided important surveys that have made possible key (and sometimes serendipitous) discoveries. I will briefly mention some of the past continuum and line (HI) radio surveys as well as new, on-going surveys and surveys planned for the near future. This new generation of large

  14. Geology of the Aspen 15-minute quadrangle, Pitkin and Gunnison counties, Colorado (United States)

    Bryant, Bruce


    The Aspen area, located 170 km southwest of Denver, Colo., lies at the intersection of the northeast-trending Colorado mineral belt and the west margin of the north-trending Sawatch uplift of Laramide age; it is within the southwest part of the northwest-trending late Paleozoic Eagle basin. Precambrian shales and graywackes, perhaps as old as 2 billion years (b.y.), were converted to sillimanite-bearing gneiss and muscovite-biotite schist 1.65-1.70 b.y. ago. They were deformed into northeast-plunging folds and were migmatized, and they were intruded by quartz diorite, porphyritic quartz monzonite, and granite. Muscovite-biotite quartz monzonite intruded this older Precambrian terrane about 1.45 b.y. ago and is the predominant Precambrian rock near Aspen. Uplift, some faulting, and much erosion occurred during the 900-million year (m.y.) interval between emplacement of the plutonic rocks and deposition of Upper Cambrian sediments. From Late Cambrian through Mississippian the region was part of a broad area alternately covered by shallow seas or occupied by low-lying land. Quartzite, dolomite, and limestone 200-320 m thick, comprising the Sawatch Quartzite and Peerless Formation (Cambrian), Manitou Dolomite (Ordovician), Chaffee Group (Mississippian(?) and Devonian), and Leadville Limestone (Mississippian) were deposited during this interval. After an hiatus during which soil formation and solution of the Leadville Limestone took place in the Late Mississippian, a thick sequence of marine and nonmarine clastic rocks was deposited in the newly developing Eagle basin during the late Paleozoic and early Mesozoic. Deposition of about 300 m of carbonaceous shale, limestone, dolomite, and minor siltstone and evaporite of the Belden Formation began in a shallow sea in Early and Middle Pennsylvanian time. Facies relations indicate that the northwest-trending Uncompahgre uplift southwest of Aspen, if present at that time, had very low relief. The overlying Middle

  15. Using Electronic Surveys: Advice from Survey Professionals.

    Directory of Open Access Journals (Sweden)

    David M. Shannon


    Full Text Available The study reports the perceptions and recommendations of sixty-two experienced survey..researchers from the American Educational Research Association regarding the use of..electronic surveys. The most positive aspects cited for the use of electronic surveys were..reduction of costs (i.e., postage, phone charges, the use of electronic mail for pre-notification or..follow-up purposes, and the compatibility of data with existing software programs. These..professionals expressed limitations in using electronic surveys pertaining to the limited..sampling frame as well as issues of confidentiality, privacy, and the credibility of the sample...They advised that electronic surveys designed with the varied technological background and..capabilities of the respondent in mind, follow sound principles of survey construction, and be..administered to pre-notified, targeted populations with published email addresses.

  16. The FLAMINGOS Extragalactic Survey (United States)

    Elston, Richard J.; Gonzalez, Anthony H.; McKenzie, Eric; Brodwin, Mark; Brown, Michael J. I.; Cardona, Gustavo; Dey, Arjun; Dickinson, Mark; Eisenhardt, Peter R.; Jannuzi, Buell T.; Lin, Yen-Ting; Mohr, Joseph J.; Raines, S. Nicholas; Stanford, S. A.; Stern, Daniel


    Using the Florida Multi-object Imaging Near-IR Grism Observational Spectrometer (FLAMINGOS), we have conducted the FLAMINGOS Extragalactic Survey (FLAMEX), a deep imaging survey covering 7.1 deg2 within the 18.6 deg2 NOAO Deep Wide-Field Survey (NDWFS) regions. FLAMEX is the first deep, wide-area, near-infrared survey to image in both the J and Ks filters, and is larger than any previous NIR survey of comparable depth. The intent of FLAMEX is to facilitate the study of galaxy and galaxy cluster evolution at 11 galaxy clusters detected using the joint FLAMEX, NDWFS, and Spitzer IRAC Shallow Survey data sets.

  17. Natural gas sources, migration and accumulation in the shallow water area of the Panyu lower uplift: An insight into the deep water prospects of the Pearl River Mouth Basin, South China Sea

    Energy Technology Data Exchange (ETDEWEB)

    Chen, H.H.; Chen, C.M.; Pang, X.; Jiahao, W.H.; Shi, W.Z. [China University of Geoscience, Wuhan (China)


    Although no drilling has been carried out in the deep water area of the Baiyun sag in the Pearl River Mouth Basin, South China Sea, the successful exploration for natural gas in the shallow water area of the Panyu lower uplift allows an insight into the prospectivity of the adjacent deep water fan system of the Baiyun sag. The Paleogene gas kitchen in the Baiyun sag provided both oil-derived gas and coal-derived gas. Fluid inclusion measurements and 2D numeric modelling of formation pressure indicate four episodes of hydrocarbon charge since the third release of the overpressure system. Seismic wipeout zones manifest several types of gas chimney which could play a role in vertical migration conduits to feed the natural gases into the deep water fan system. There would be, therefore, a low risk for hydrocarbon exploration in the deep water fan system.

  18. 75 FR 8739 - Notice of Intent To Prepare a Resource Management Plan for the Uncompahgre Field Office and... (United States)


    ... announced 15 days in advance through local media, a newsletter and the BLM Web site at: Management; Fire Ecology and Management; Cultural Resources and Native American Concerns; Hydrology; Geology...

  19. Sea Scallop Survey (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The standardized NEFSC Sea Scallop Survey began in 1980 and has covered an area from Cape Hatteras to Georges Bank. The survey aims to determine the distribution and...

  20. Black Rail Pilot Survey (United States)

    US Fish and Wildlife Service, Department of the Interior — Aural surveys using tape recorded calls proved to be an efficient and effective way to survey large expanses of shallow marsh for black rails (Laterallus...


    Federal Emergency Management Agency, Department of Homeland Security — Survey data includes spatial datasets and data tables necessary to digitally represent data collected in the survey phase of the study. (Source: FEMA Guidelines and...

  2. SURVEY, RICE COUNTY, MN (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Survey data includes spatial datasets and data tables necessary to digitally represent data collected in the survey phase of the study. (Source: FEMA Guidelines and...

  3. SURVEY, HOLMES COUNTY, MS (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Survey data includes spatial datasets and data tables necessary to digitally represent data collected in the survey phase of the study. (Source: FEMA Guidelines and...

  4. SURVEY, CITRUS County, FL (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Survey data includes spatial datasets and data tables necessary to digitally represent data collected in the survey phase of the study. (Source: FEMA Guidelines and...

  5. Large Pelagics Intercept Survey (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Large Pelagics Intercept Survey (LPIS) is a dockside survey of private and charterboat captains who have just completed fishing trips directed at large pelagic...

  6. Global Land Survey (United States)

    U.S. Geological Survey, Department of the Interior — The Global Land Survey (GLS) datasets are a collection of orthorectified, cloud-minimized Landsat-type satellite images, providing near complete coverage of the...

  7. Iowa Intensive Archaeological Survey (United States)

    Iowa State University GIS Support and Research Facility — This shape file contains intensive level archaeological survey areas for the state of Iowa. All intensive Phase I surveys that are submitted to the State Historic...

  8. SURVEY, KENT COUNTY, MD (United States)

    Federal Emergency Management Agency, Department of Homeland Security — The field survey data for this coastal study includes a field report that exhibits photos and transect information collected in the field survey phase of the study....

  9. SURVEY, Cecil County, MD (United States)

    Federal Emergency Management Agency, Department of Homeland Security — The field survey data for this coastal study includes a field report that exhibits photos and transect information collected in the field survey phase of the study....

  10. SURVEY, KENT COUNTY, DE (United States)

    Federal Emergency Management Agency, Department of Homeland Security — The field survey data for this coastal study includes a field report that exhibits photos and transect information collected in the field survey phase of the study....

  11. Patient survey (HCAHPS) - National (United States)

    U.S. Department of Health & Human Services — The national average for the HCAHPS survey categories. HCAHPS is a national, standardized survey of hospital patients about their experiences during a recent...

  12. Patient survey (HCAHPS) - State (United States)

    U.S. Department of Health & Human Services — A list of the state averages for the HCAHPS survey responses. HCAHPS is a national, standardized survey of hospital patients about their experiences during a recent...


    Federal Emergency Management Agency, Department of Homeland Security — Survey data includes spatial datasets and data tables necessary to digitally represent data collected in the survey phase of the study. (Source: FEMA Guidelines and...


    Federal Emergency Management Agency, Department of Homeland Security — Survey data includes spatial datasets and data tables necessary to digitally represent data collected in the survey phase of the study. (Source: FEMA Guidelines and...

  15. 1998 Harrisburg Airport Survey (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set includes data collected in 1998 to evaluate the ability of lidar to survey airport obstructions in collaboration with NOAA National Geodetic Survey....

  16. National Health Care Survey (United States)

    This survey encompasses a family of health care provider surveys, including information about the facilities that supply health care, the services rendered, and the characteristics of the patients served.

  17. HCAHPS Hospital Survey (United States)

    U.S. Department of Health & Human Services — Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) Hospital Survey The intent of the HCAHPS initiative is to provide a standardized survey...

  18. SURVEY, CASCADE COUNTY, MT (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Survey data includes spatial datasets and data tables necessary to digitally represent data collected in the survey phase of the study. (Source: FEMA Guidelines and...

  19. NGS Survey Control Map (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NGS Survey Control Map provides a map of the US which allows you to find and display geodetic survey control points stored in the database of the National...


    Federal Emergency Management Agency, Department of Homeland Security — Survey data includes spatial datasets and data tables necessary to digitally represent data collected in the survey phase of the study. (Source: FEMA Guidelines and...

  1. MAX and Survey Linkages (United States)

    U.S. Department of Health & Human Services — CMS is interested in linking MAX files with survey data, including four surveys conducted by the National Center for Health Statistics (NCHS) - the National Health...

  2. Designing an Effective Survey

    National Research Council Canada - National Science Library

    Kasunic, Mark


    ... of them. However, to protect the validity of conclusions drawn from a survey, certain procedures must be followed throughout the process of designing, developing, and distributing the survey questionnaire...

  3. GIS Readiness Survey 2014

    DEFF Research Database (Denmark)

    Schrøder, Lise; Hvingel, Line Træholt; Hansen, Henning Sten


    The GIS Readiness Survey 2014 is a follow-up to the corresponding survey that was carried out among public institutions in Denmark in 2009. The present survey thus provides an updated image of status and challenges in relation to the use of spatial information, the construction of the com- mon...

  4. Survey It: Appraising Schools. (United States)

    Klimes, Rudolf E.

    A survey in education describes the present condition of an educational program and forms the basis for knowing what is happening in a particular school. This volume is intended to be a practical guide to school surveying in South Korea, but not a scholarly thesis on surveys. The emphasis is on field studies and how surveyors can perform a school…

  5. Primer on Health Surveys

    Directory of Open Access Journals (Sweden)

    David L Nordstrom


    Full Text Available The aim of this paper is to introduce novice researchers to surveys as a method of data collection. It starts with the definition of a survey, its major purposes and types as well as changes in the goals surveys have helped to achieve over time. Advantages and disadvantages of surveys over population censuses and medical examinations are discussed. Approaches to questionnaire construction are introduced along with properties that questionnaires are evaluated for. Modes of administration, sample size issues, and data analysis approaches are also introduced. The primer is illustrated with examples of surveys conducted in different countries with various public health purposes.

  6. Environmental Survey preliminary report

    Energy Technology Data Exchange (ETDEWEB)


    This report presents the preliminary findings from the first phase of the Environmental Survey of the United States Department of Energy (DOE) Sandia National Laboratories conducted August 17 through September 4, 1987. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with Sandia National Laboratories-Albuquerque (SNLA). The Survey covers all environmental media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. This phase of the Survey involves the review of existing site environmental data, observations of the operations carried on at SNLA, and interviews with site personnel. 85 refs., 49 figs., 48 tabs.

  7. The FLAMINGOS Extragalactic Survey


    Elston, Richard J.; Gonzalez, Anthony H.; McKenzie, Eric; Brodwin, Mark; Brown, Michael J. I.; Cardona, Gustavo; Dey, Arjun; Dickinson, Mark; Eisenhardt, Peter R.; Jannuzi, Buell T.; Lin, Yen-Ting; Mohr, Joseph J.; Raines, S. Nicholas; Stanford, S. A.; Stern, Daniel


    Using the Florida Multi-object Imaging Near-IR grism Observational Spectrometer (FLAMINGOS), we have conducted the FLAMINGOS Extragalactic Survey (FLAMEX), a deep imaging survey covering 7.1 square degrees within the 18.6 sq. deg NOAO Deep Wide-Field Survey (NDWFS) regions. FLAMEX is the first deep, wide-area near-infrared survey to image in both the J and Ks filters, and is larger than any previous NIR surveys of comparable depth. The intent of FLAMEX is to facilitate the study of galaxy and...

  8. Survey of photovoltaic systems

    Energy Technology Data Exchange (ETDEWEB)


    In developing this survey of photovoltaic systems, the University of Alabama in Huntsville assembled a task team to perform an extensive telephone survey of all known photovoltaic manufacturers. Three US companies accounted for 77% of the total domestic sales in 1978. They are Solarex Corporation, Solar Power Croporation, and ARCO Solar, Inc. This survey of solar photovoltaic (P/V) manufacturers and suppliers consists of three parts: a catalog of suppliers arranged alphabetically, data sheets on specific products, and typical operating, installation, or maintenance instructions and procedures. This report does not recommend or endorse any company product or information presented within as the results of this survey.

  9. Management Satisfaction Survey (United States)

    Office of Personnel Management — The Chief Human Capital Officers' Managers' Satisfaction Survey asks managers to rate their perception of workforce planning, interaction with and levels of support...

  10. Alumni Perspectives Survey, 2011. Survey Report (United States)

    Sheikh, Sabeen


    Since the Graduate Management Admission Council[R] (GMAC[R]) first began conducting its Alumni Perspectives Surveys 11 years ago, several "truths" about graduate business school alumni have consistently stood the test of time: They are and remain eminently employable. They constantly rate the value of the degree highly. This year's results are…

  11. Corporate Recruiters Survey: 2014 Survey Report (United States)

    Estrada Worthington, Rebecca


    The 2014 Corporate Recruiters Survey Report examines the current hiring outlook for graduate business students and analyzes demand by industry and world region, salaries, job functions, and mobility in regional job placement. It also explores recruiter behavior, including recruitment practices and school and candidate selection criteria, and…

  12. A Survey of the Innovation Surveys

    NARCIS (Netherlands)

    Hong, Shangqin; Oxley, Les; McCann, Philip

    Both theoretical and conceptual understanding of innovation has developed significantly since the early 1980s. More noticeable, however, are the major changes that have been experienced in empirically-oriented innovation research as a result of the introduction of firm level innovation surveys.

  13. Detail and survey radioautographs

    Energy Technology Data Exchange (ETDEWEB)

    Wainwright, Wm.W.


    The much used survey or contact type of radioautograph is indispensible for a study of the gross distribution of radioactive materials. A detail radioautograph is equally indispensible. The radioautograph makes possible the determination of plutonium with respect to cells. Outlines of survey and detail techniques are given.

  14. Cosmology with cluster surveys

    Indian Academy of Sciences (India)

    Surveys of clusters of galaxies provide us with a powerful probe of the density and nature of the dark energy. The red-shift distribution of detected clusters is highly sensitive to the dark energy equation of state parameter . Upcoming Sunyaev–Zel'dovich (SZ) surveys would provide us large yields of clusters to very high ...

  15. Cosmology with cluster surveys

    Indian Academy of Sciences (India)

    Cosmology with cluster surveys. SUBHABRATA MAJUMDAR. CITA, University of Toronto, Toronto, ON, M5S 3H8, Canada. E-mail: Abstract. Surveys of clusters of galaxies provide us with a powerful probe of the den- sity and nature of the dark energy. The red-shift distribution of detected clusters is.

  16. The Wsrt Halogas Survey

    NARCIS (Netherlands)

    Heald, George

    We present an overview of the HALOGAS (Hydrogen Accretion in LOcal GAlaxieS) Survey, which is the deepest systematic investigation of cold gas accretion in nearby spiral galaxies to date. Using the deep H i data that form the core of the survey, we are able to detect neutral hydrogen down to a

  17. Problems with Institutional Surveys. (United States)

    Frey, James H.


    A survey done properly by accepted and scientifically justifiable techniques can provide information on behalf of the goals of institutional advancement in academe. Deficiencies in institutional research are seen as the result of the lack of guidance on survey design, questionnaire construction, or problem definition in education research texts.…

  18. Sandhills native bee survey (United States)

    US Fish and Wildlife Service, Department of the Interior — This report includes the results of a bee survey conducted in Sandhills region of north and south Carolina on May 18th and 19th 2006. Part of the survey was...

  19. IT Barometer survey, Denmark

    DEFF Research Database (Denmark)

    Howard, Rob


    Survey results from Danish architects, engineers, contractors and property managers in the construction industry concerning their use of computers, communications, problems and needs.......Survey results from Danish architects, engineers, contractors and property managers in the construction industry concerning their use of computers, communications, problems and needs....

  20. Managing Online Survey Data (United States)

    Ritter, Lois A., Ed.; Sue, Valerie M., Ed.


    Managing data collected from online surveys may be a straightforward process involving no more than downloading a spreadsheet from a Web survey host and presenting descriptive statistics associated with each questionnaire item. On the other hand, if the evaluation objectives require more complex analysis and presentation of the data, it will be…

  1. 2007 Maryland Adolescent Survey (United States)

    Maryland State Department of Education, 2008


    Periodically, Maryland's sixth, eighth, tenth, and twelfth graders are surveyed to determine the nature, extent, and trend of alcohol, tobacco, and other drug (ATOD) use among adolescents. The "2007 Maryland Adolescent Survey (MAS)" presents the latest findings regarding ATOD use by Maryland's adolescents and compares State and local…

  2. Survey team on

    DEFF Research Database (Denmark)

    Niss, Mogens Allan; Bruder, Regina; Planas, Núria


    This paper presents the outcomes of the work of the ICME 13 Survey Team on ‘Conceptualisation and the role of competencies, knowing and knowledge in mathematics education research’. It surveys a variety of historical and contemporary views and conceptualisations of what it means to master...

  3. Physics Survey Overview

    Energy Technology Data Exchange (ETDEWEB)



    An overview of a series of assignments of the branches of physics carried out by the Board on Physics and Astronomy of the National Research Council. It identifies further theories in physics and makes recommendations on preventive priorities. The Board on Physics and Astronomy (BPA) has conducted a new decadal survey of physics entitled ''Physics in a New Era''. The survey includes assessments of the main branches of physics as well as certain selected emerging areas. The various elements of the survey were prepared by separately-appointed National Research Council (NRC) committees. The BPA formed the Physics Survey Overview Committee (PSOVC) to complete the survey by preparing an overview of the field of physics to summarize and synthesize the results of the various assessments and to address cross-cutting issues that concern physics as a whole.

  4. The VLA Sky Survey (United States)

    Lacy, Mark; VLASS Survey Team, VLASS Survey Science Group


    The VLA Sky Survey (VLASS), which began in September 2017, is a seven year project to image the entire sky north of Declination -40 degrees in three epochs. The survey is being carried out in I,Q and U polarization at a frequency of 2-4GHz, and a resolution of 2.5 arcseconds, with each epoch being separated by 32 months. Raw data from the survey, along with basic "quicklook" images are made freely available shortly after observation. Within a few months, NRAO will begin making available further basic data products, including refined images and source lists. In this talk I shall describe the science goals and methodology of the survey, the current survey status, and some early results, along with plans for collaborations with external groups to produce enhanced, high level data products.

  5. Estimation of palaeo-slope and sediment volume of a lacustrine rift basin: A semi-quantitative study on the southern steep slope of the Shijiutuo Uplift, Bohai Offshore Basin, China (United States)

    Liu, Hao; Meng, Jun; Banerjee, Santanu


    The sequence architecture and depositional systems of the Palaeogene lacustrine rift succession in the southern steep slope of the Shijiutuo Uplift (SU) in Bohai Offshore Basin (BOB) were investigated using combined 3-D seismic, well log and core data. Four second-order/composite sequences and seven third-order sequences were identified. A detailed analysis revealed fan delta, braid delta and lacustrine depositional systems in the third-order sequences 7 (SQ7). Eleven seismic facies were chosen in the SQ7 to calculate the area and sediment budget. We also calculated the palaeo-slope parameters in the southern steep slope of the SU, including the gradient of basin margin fault slope belt, the shape, average width, average height, width/height ratio and cross sectional area of palaeo-valley. The gradient of the fault slope break belt was inversely proportional to the area and volume of sediments. The higher gradient corresponded to the smaller area and volume of sediments. The width and cross sectional area of palaeo-valleys dominated the volume and facies of sediments. A larger cross sectional area of a palaeo-valley involved much more sediments supply and more favorable conditions for the origin of large-scale deltas. Because of favorable sediment transportation path and existence of large-scale braid delta, the eastern part of the SU formed better quality reservoir than that in the west.


    CERN Multimedia


    University of Southampton invites the CERN community to participate in a survey Professor Stevan Harnad is conducting on current users and non-users of Eprint Archives. The findings will be used to suggest potential enhancements of the services as well as to get a deeper understanding of the very rapid developments in the on-line dissemination and use of scientific and scholarly research. (The survey is anonymous. Revealing your identity is optional and it will be kept confidential.)

  7. GPS satellite surveying

    CERN Document Server

    Leick, Alfred; Tatarnikov, Dmitry


    THE MOST COMPREHENSIVE, UP-TO-DATE GUIDE ON GPS TECHNOLOGY FOR SURVEYING Three previous editions have established GPS Satellite Surveying as the definitive industry reference. Now fully updated and expanded to reflect the newest developments in the field, this Fourth Edition features cutting-edge information on GNSS antennas, precise point positioning, real-time relative positioning, lattice reduction, and much more. Expert authors examine additional tools and applications, offering complete coverage of geodetic surveying using satellite technologies. The past decade has seen a major evolut

  8. Telephony user survey

    CERN Multimedia

    IT Department


    Let us know your needs to better plan the transition to a new CERN telephony system.   CERN is planning to upgrade its telephony network and replace the system with a new and modern VoIP infrastructure. We strive to make this transition as beneficial and smooth as possible for you. Please let us know more about your current working environment, expectations and suggestions by responding to this survey: The more answers we get, the better the new system will serve everyone in the future. The survey will take you about five minutes to complete; we are counting on your feedback!

  9. Billfish Angler Survey (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Billfish Angler Survey provides estimates of billfish angling activities in the Pacific and Indian Oceans. This collection of recreational billfish catch and...

  10. Wolf Population Survey (United States)

    US Fish and Wildlife Service, Department of the Interior — Snow track surveys are a common method of estimating relative abundance, estimating density, and documenting range use of furbearers and large carnivores. The...

  11. Industry Based Monkfish Survey (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Monkfish industry leaders expressed concerns that the NEFSC bottom trawl surveys did not sample in all monkfish habitats; particularly the deeper water outside the...

  12. National Nursing Home Survey (United States)

    The National Nursing Home Survey provides includes characteristics such as size of nursing home facilities, ownership, Medicare/Medicaid certification, occupancy rate, number of days of care provided, and expenses.

  13. Winter Bottom Trawl Survey (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The standardized NEFSC Winter Bottom Trawl Survey was initiated in 1992 and covered offshore areas from the Mid-Atlantic to Georges Bank. Inshore strata were covered...

  14. ASD Customer Satisfaction Survey (United States)

    Department of Veterans Affairs — ASD implemented a customer satisfaction survey for our products and services. This feedback will provide a better understanding of how ASD products and services can...

  15. Hake Survey ADCP (2005) (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Shipboard acoustic Doppler current profiler data collected during the Integrated Acoustic and Trawl Surveys of Pacific Hake. Processing by: Stephen Pierce, Oregon...

  16. Hake Survey ADCP (1998) (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Shipboard acoustic Doppler current profiler data collected during the Integrated Acoustic and Trawl Surveys of Pacific Hake. Processing by: Stephen Pierce, Oregon...

  17. Hake Survey ADCP (2003) (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Shipboard acoustic Doppler current profiler data collected during the Integrated Acoustic and Trawl Surveys of Pacific Hake. Processing by: Stephen Pierce, Oregon...

  18. Hake Survey ADCP (2001) (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Shipboard acoustic Doppler current profiler data collected during the Integrated Acoustic and Trawl Surveys of Pacific Hake. Processing by: Stephen Pierce, Oregon...

  19. Infrared Sky Surveys (United States)

    Price, Stephan D.


    A retrospective is given on infrared sky surveys from Thomas Edison’s proposal in the late 1870s to IRAS, the first sensitive mid- to far-infrared all-sky survey, and the mid-1990s experiments that filled in the IRAS deficiencies. The emerging technology for space-based surveys is highlighted, as is the prominent role the US Defense Department, particularly the Air Force, played in developing and applying detector and cryogenic sensor advances to early mid-infrared probe-rocket and satellite-based surveys. This technology was transitioned to the infrared astronomical community in relatively short order and was essential to the success of IRAS, COBE and ISO. Mention is made of several of the little known early observational programs that were superseded by more successful efforts.

  20. ALMS Surveys 2010 (United States)

    US Fish and Wildlife Service, Department of the Interior — The Alaska Landbird Monitoring Survey (ALMS) program is a cooperative statewide program established to monitor population trends of landbirds and other birds across...

  1. ALMS Surveys 2011 (United States)

    US Fish and Wildlife Service, Department of the Interior — The Alaska Landbird Monitoring Survey (ALMS) program is a cooperative statewide program established to monitor population trends of landbirds and other birds across...

  2. American Housing Survey (AHS) (United States)

    Department of Housing and Urban Development — The AHS is the largest, regular national housing sample survey in the United States. The U.S. Census Bureau conducts the AHS to obtain up-to-date housing statistics...

  3. Midwinter Bald Eagle Survey (United States)

    US Fish and Wildlife Service, Department of the Interior — The purpose of the Midwinter Bald Eagle survey is to monitor the status of Bald Eagle wintering populations in the contiguous United States by estimating national...

  4. 2011 Resident Survey (United States)

    City and County of Durham, North Carolina — The purpose of the annual City/County survey: To objectively assess citizen satisfaction with the delivery of City/County servicesTo set a baseline for future...

  5. 2005 Resident Survey (United States)

    City and County of Durham, North Carolina — The purpose of the annual City/County survey: To objectively assess citizen satisfaction with the delivery of City/County servicesTo set a baseline for future...

  6. Hake Survey ADCP (1995) (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Shipboard acoustic Doppler current profiler data collected during the Integrated Acoustic and Trawl Surveys of Pacific Hake. Processing by: Stephen Pierce, Oregon...

  7. Lesotho - Health Facility Survey (United States)

    Millennium Challenge Corporation — The main objective of the 2011 Health Facility Survey (HFS) was to establish a baseline for informing the Health Project performance indicators on health facilities,...

  8. NWRS Survey Prioritization Tool (United States)

    US Fish and Wildlife Service, Department of the Interior — A SMART Tool and User's Guide for aiding NWRS Station staff when prioritizing their surveys for an Inventory and Monitoring Plan. This guide describes a process and...

  9. Fisheries Disaster Survey, 2000 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Responses to selected questions from the Social and Economic Survey administered in spring and summer 2000 to recipients of the second round (Round II) of financial...

  10. Fall Bottom Trawl Survey (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The standardized NEFSC Fall Bottom Trawl Survey was initiated in 1963 and covered an area from Hudson Canyon, NY to Nova Scotia, Canada. Throughout the years,...

  11. Atlantic Herring Acoustic Surveys (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Advanced Sampling Technologies Research Group conducts annual fisheries acoustic surveys using state-of-the-art acoustic, midwater trawling, and underwater...

  12. Newfoundland: an industrial survey

    National Research Council Canada - National Science Library


    ... the establishment of a plant in Newfoundland. Included are surveys covering the cities of St. John's and Corner Brook and the towns of Gander, Grand Falls, and Stephenville, with added data on supporting areas...

  13. 2007 Resident Survey (United States)

    City and County of Durham, North Carolina — The purpose of the annual City/County survey: To objectively assess citizen satisfaction with the delivery of City/County servicesTo set a baseline for future...

  14. 2013 Resident Survey (United States)

    City and County of Durham, North Carolina — The purpose of the annual City/County survey: To objectively assess citizen satisfaction with the delivery of City/County servicesTo set a baseline for future...

  15. 2009 Resident Survey (United States)

    City and County of Durham, North Carolina — The purpose of the annual City/County survey: To objectively assess citizen satisfaction with the delivery of City/County servicesTo set a baseline for future...

  16. Large Pelagics Telephone Survey (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Large Pelagics Telephone Survey (LPTS) collects fishing effort information directly from captains holding Highly Migratory Species (HMS) permits (required by...

  17. Deep Water Survey Data (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The deep water biodiversity surveys explore and describe the biodiversity of the bathy- and bentho-pelagic nekton using Midwater and bottom trawls centered in the...

  18. NMFS Reef Survey Forms (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Reef Environmental Survey Project (REEF) mission to educate and enlist divers in the conservation of marine habitats is accomplished primarily through its Fish...

  19. National Health Interview Survey (United States)

    U.S. Department of Health & Human Services — The National Health Interview Survey (NHIS) is the principal source of information on the health of the civilian noninstitutionalized population of the United States...

  20. Large Pelagics Biological Survey (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Large Pelagics Biological Survey (LPBS) collects additional length and weight information and body parts such as otoliths, caudal vertebrae, dorsal spines, and...

  1. Artesian Wetlands Survey (United States)

    US Fish and Wildlife Service, Department of the Interior — The Artesian Wetlands Survey includes data on the wetlands in the San Luis Valley in Colorado. Data recorded includes location, area of influence, area inundated,...

  2. Patient survey (HCAHPS) - Hospital (United States)

    U.S. Department of Health & Human Services — A list of hospital ratings for the Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS). HCAHPS is a national, standardized survey of hospital...

  3. Medicare Current Beneficiary Survey (United States)

    U.S. Department of Health & Human Services — The Characteristics and Perceptions of the Medicare Population Data from the 2010 Medicare Current Beneficiary Survey is a series of source books based on the...

  4. Patient survey (ICH CAHPS) (United States)

    U.S. Department of Health & Human Services — In-Center Hemodialysis Facilites Patient evaluations from the In-Center Hemodialysis Consumer Assessment of Healthcare Providers and Systems (ICH-CAHPS) Survey. The...

  5. IT User Community Survey

    CERN Multimedia

    Peter Jones (IT-CDA-WF)


    IT-CDA is gathering information to more accurately form a snapshot of the CERN IT user community and we would appreciate you taking time to complete the following survey.   We want to use this survey to better understand how the user community uses their devices and our services, and how the delivery of those services could be improved. You will need to authenticate to complete the survey. However please note that your responses are confidential and will be compiled together and analysed as a group. You can also volunteer to offer additional information if you so wish. This survey should take no longer than 5 minutes. Thanks in advance for your collaboration.

  6. Web surveys' hidden hazards. (United States)

    Morrel-Samuels, Palmer


    The same question posed on the Web and in print can yield very different answers, dramatically distorting survey results and misleading management. But, as psychologist Palmer Morrel-Samuels demonstrates, the problems are readily fixed.

  7. Applicant Satisfaction Survey (United States)

    Office of Personnel Management — The Chief Human Capital Officers developed 3 surveys that asks applicants to assess their satisfaction with the application process on a 1-10 point scale, with 10...

  8. Shrimp Survey Data (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Northern Shrimp Survey was initiated in 1983 by the Atlantic States Marine Fisheries Commission (ASMFC) and monitors the relative abundance (number of shrimp),...

  9. Waterfowl breeding population survey (United States)

    US Fish and Wildlife Service, Department of the Interior — Waterfowl breeding population surveys have been completed annually on the Arctic Coastal Plain of Alaska since 1986. Methods for the 2011 Arctic Coastal Plain...

  10. Waterfowl breeding population survey (United States)

    US Fish and Wildlife Service, Department of the Interior — Waterfowl breeding population surveys have been completed annually on the Arctic Coastal Plain of Alaska since 1986. Methods for the 2010 Arctic Coastal Plain...

  11. Spring Bottom Trawl Survey (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The standardized NEFSC Spring Bottom Trawl Survey was initiated in 1968 and covered an area from Cape Hatteras, NC, to Nova Scotia, Canada, at depths >27m....

  12. Benchmarking survey for recycling.

    Energy Technology Data Exchange (ETDEWEB)

    Marley, Margie Charlotte; Mizner, Jack Harry


    This report describes the methodology, analysis and conclusions of a comparison survey of recycling programs at ten Department of Energy sites including Sandia National Laboratories/New Mexico (SNL/NM). The goal of the survey was to compare SNL/NM's recycling performance with that of other federal facilities, and to identify activities and programs that could be implemented at SNL/NM to improve recycling performance.

  13. DSM-5 field survey

    DEFF Research Database (Denmark)

    Lochner, Christine; Grant, Jon E; Odlaug, Brian Lawrence


    The aim of this multisite field survey was to examine the DSM-IV-TR criteria, proposed DSM-5 diagnostic criteria, as well as a number of possible additional diagnostic criteria, in patients with hair-pulling disorder (HPD, or trichotillomania).......The aim of this multisite field survey was to examine the DSM-IV-TR criteria, proposed DSM-5 diagnostic criteria, as well as a number of possible additional diagnostic criteria, in patients with hair-pulling disorder (HPD, or trichotillomania)....

  14. Site surveying and levelling

    CERN Document Server

    Clancy, John


    This popular and useful text has been completely revised and up-dated so that it forms and indipensible handbook for any student of surveying. An additional chapter on modern developments is included and the text has also been extended to cover ordnance survey; calculation of areas; computation of true horizontal length; measurement of vertical angles; Code of Measuring Practice; curve ranging and calculations of volumes for earthworks.

  15. The Chile tsunami of 27 February 2010: Field survey and modeling (United States)

    Fritz, H. M.; Petroff, C. M.; Catalan, P. A.; Cienfuegos, R.; Winckler, P.; Kalligeris, N.; Weiss, R.; Meneses, G.; Valderas-Bermejo, C.; Barrientos, S. E.; Ebeling, C. W.; Papadopoulos, A.; Contreras, M.; Almar, R.; Dominguez, J.; Synolakis, C.


    On 27 February, 2010 a magnitude Mw 8.8 earthquake occurred off the coast of Chile's Maule region some 100 km N of Concepción, causing substantial damage and loss of life on Chile's mainland and the Juan Fernandez archipelago. The majority of the 521 fatalities are attributed to the earthquake, while the tsunami accounts for 124 victims. Fortunately, ancestral knowledge from past tsunamis such as the giant 1960 event, as well as tsunami education and evacuation exercises prompted most coastal residents to spontaneously evacuate to high ground after the earthquake. The majority of the tsunami victims were tourists staying overnight in low lying camp grounds along the coast. A multi-disciplinary international tsunami survey team (ITST) was deployed within days of the event to document flow depths, runup heights, inundation distances, sediment deposition, damage patterns at various scales, performance of the man-made infrastructure and impact on the natural environment. The 3 to 25 March ITST covered an 800 km stretch of coastline from Quintero to Mehuín in various subgroups the Pacific Islands of Santa María, Juan Fernández Archipelago, and Rapa Nui (Easter), while Mocha Island was surveyed 21 to 23 May, 2010. The collected survey data includes more than 400 tsunami runup and flow depth measurements. The tsunami impact peaked with a localized maximum runup of 29 m on a coastal bluff at Constitución and 23 m on marine terraces on Mocha Island. A significant variation in tsunami impact was observed along Chile's mainland both at local and regional scales. Inundation and damage also occurred several kilometres inland along rivers. Eyewitness tsunami videos are analysed and flooding velocities presented. Observations from the Chile tsunami are compared against the 1960 Chile, 2004 Indian Ocean and 2011 Tohoku Japan tsunamis. The tsunamigenic seafloor displacements were partially characterized based on coastal uplift measurements along a 100 km stretch of coastline

  16. Comment on "Cenozoic tectonic deformation and uplift of the South Tian Shan: Implications from magnetostratigraphy and balanced cross-section restoration of the Kuqa depression" by Tao Zhang, Xiaomin Fang, Chunhui Song, Erwin Appel, and Yadong Wang [Tectonophysics, 2014, doi:10.1016/j.tecto.2014.04.044 (United States)

    Qiao, Qingqing; Huang, Baochun; Piper, John D. A.


    The recent paper entitled: "Cenozoic tectonic deformation and uplift of the South Tian Shan: Implications from magnetostratigraphy and balanced cross-section restoration of the Kuqa depression" by Zhang et al. [Tectonophysics, 2014, doi:10.1016/j.tecto.2014.04.044] discusses the Cenozoic tectonic deformation and uplift of the South Tianshan Mountains by integrating tectonic investigations, seismostratigraphic analysis and paleomagnetic dating of the thrust-fold belt in the Kuqa Depression at the southern border of the Tianshan. To support their conclusions the authors have reinterpreted a high resolution magnetostratigraphic study of the Kezilenuer Section in a paper entitled "Magnetostratigraphic study of the Kuche Depression, Tarim Basin, and Cenozoic uplift of the Tian Shan Range, Western China" by Huang et al. [Earth and Planetary Science Letters Volume 251, pages 346-364 (2006)]. We note here (i) that apparent conflicts in definition of the Xiyu Formation in the Kuche Depression as proposed by Zhang et al. (2014) require amplification and (ii) argue that their age assignment for the Kezilenuer Section is incorrect and yields an anomalously low sedimentation rate for the infilling of this foreland basin.

  17. Differential uplift and denudation of the Kungei and Terzkey ranges bordering the Issyk-Kul intermontane basin, Kyrgyz Tien Shan mountains (Central Asia): constraints from apatite fission-track analysis (United States)

    de Grave, J.; Buslov, M. M.; van den Haute, P.


    The Tien Shan mountain belt forms one of the most active intracontinental belts in the world. Its Cenozoic evolution is directly related to ongoing convergence of the Indian and Eurasian plates. The Tien Shan are draped along the northern rim of the rigid and stable Tarim Basin in Central Asia, north of the Tibetan Plateau. The mountain belt is composed of E-W trending ranges, alternating with intermontane basins. The lens shaped Issyk-Kul (IK) basin in northern Kyrgyzstan is a striking example of such a basin and accommodates the Issyk-Kul Lake. It is bordered by the Kungei (north) and the Terzkey ranges (south). While the present lake level is situated at 1607 m a.s.l., the elevation of both ranges reaches 5000 m. Both mountain ranges (cored by pink Ordovician granites and exhibiting large altitude differences) were sampled for AFT analysis along elevation profiles. In addition, samples from other IK basement rocks were collected in areas outside the ranges. AFT ages in the Kungei range fall roughly between 120 Ma and 170 Ma, while those for the Terzkey range were substantially lower (60 Ma to 110 Ma). The additional basement apatites sampled throughout the area have ages between 110 Ma and 160 Ma, corresponding to those of the Kungei range. The Kungei age-elevation plot is quite normal with ages decreasing with decreasing altitude, while the Terzkey range samples exhibit additional scatter. No "break in slope" is observed in any of the profiles and this together with the fact that all track length distributions carry a substantial Apatite Partial Annealing Zone signature (mean lengths are between 12.5 and 13.0 µm for both ranges) gives evidence of the mixed nature of the AFT ages. In contrast with the AFT data by Bullen et al. (2001) from the Kyrgyz range to the west of the IK basin, no late Cenozoic AFT ages were found for our samples. Hence the active tectonic phase experienced by the Tien Shan since the Late Miocene must undoubtedly have uplifted the Kungei

  18. Retirement Applicant Satisfaction Survey Results (United States)

    Social Security Administration — This dataset contains information about the Retirement Applicant Survey (RAS). The survey measured satisfaction results with the retirement application process. The...


    CERN Multimedia


    The primary role of the library is to make sure that you can do YOUR work in the most efficient way possible. To ensure that we continue to match our services to your information needs, the library regularly gathers the views and opinions of its readers in a variety of ways, [link for e-version: http://library/library_general/statistics/library_statistics_ surveys.html], including user surveys. The last survey was carried out in 1996. One of the most visible results of that survey was the extension of the library desk service until seven o'clock in the evening, to meet the demand for greater access to library materials. Now the 'electronic library' is becoming more important than the physical one, we feel it is once again time to ensure that we are providing the services and information you need, in the most effective way possible. We also want to make sure you are aware of the full range of services that the library provides. Please spare just a few minutes to fill out our survey at


    Directory of Open Access Journals (Sweden)

    C. Mileto


    Full Text Available In addition to the technological evolution over the last two centuries, survey has experienced two main conceptual leaps: the introduction of photography as a tool for an indiscriminate register for reality, and the shift from autographic to allographic survey, phenomena which can generate a distancing effect within the restoration process. Besides, this text presents the relationship between survey in its numerous forms and technologies (manual and semi-manual to more complex ones like scanner-laser and the restoration of the building, either for establishing a diagnosis, operating or valorizating, illustrating it with examples developed by the authors, as well as the criteria to be applied when documenting a building to be restored, irrespective of the means and technology available in each case.

  1. Conical polyurethane implants: an uplifting augmentation. (United States)

    Georgeu, Garrick A; Frame, James D; Frame, James D


    Polyurethane-coated conical implants were introduced by Silimed (US distributor: Sientra, Santa Barbara, California) in 2008 and offer an alternative to round or anatomically shaped implants. By their design and volume distribution, they naturally create central volume and give a reasonable fullness to the upper pole while lifting some ptotic breasts, thus avoiding the need for classical mastopexy. The authors discuss the advantages of conical implants as an alternative to conventional silicone implants for women with breast ptosis. In the 2-year period between December 2010 and December 2012, a consecutive series of 302 women underwent implant-based breast surgery procedures (236 primary augmentations, 59 revisions, and 7 mastopexy-augmentations) with conical polyurethane devices. Implant volumes ranged from 225 to 560 cc, with low- to medium-profile devices predominating. No extra-high-profile implants were used. Only 1 patient had a drain inserted on completion of a revision augmentation. There were no infections (0%) and no wound dehiscence (0%). Four cases required reoperation (1.3%). Patient satisfaction scores were universally high (average, 9.94/10). There have been no capsular contractures to date, but follow-up is short. The modern conical, polyurethane implant has many advantages over the conventional round or anatomically shaped implants and offers patients an ideal compromise between volume, natural upper pole fullness, and a lift without mastopexy scars.

  2. Uplift of the Eastern Cordillera, Colombia (United States)

    Siravo, Gaia; Faccenna, Claudio; Giuditta Fellin, Maria; Molin, Paola; Bayona, German; Giachetta, Emanuele


    The Eastern Cordillera (EC) of Colombia is a double-vergent thrust and fold belt formed during the Cenozoic by the inversion of a Mesozoic rift. It is located 400 km far from the trench where the Nazca slab subducts below the South American plate. Tomography and seismicity highlight the presence of a flat slab subduction north of 5° N. Our goal is to explore the relation between surface and crustal processes in the topography growth of the EC north of 6° N. To reach this aim we integrate data derived from the fluvial network analysis with long-term erosion data derived from thermochronology. The northern EC is an asymmetric chain with a gentle flank on the western side and steep flank to the east. The two sides are separated by the maximum elevation of 5000 m reached at the Cocuy Sierra. Here the EC has the widest width ( 200 km) and changes northward to the Santander Massif Range. We obtained new low-T (U-Th)/He ages on zircons (ZHe) and apatites (AHe) from samples collected along two transects. Our ages combined with previous data indicate that along both transects exhumation occurred from shallow burial depths (≤ 6-8 km) during the Oligo-Miocene and locally continued until the Pliocene. Along the transect across the central part of the EC up to the Cocuy Sierra, the youngest Pliocene ages (AHe) are located at the highest elevations above 4000 m. Along the second transect the youngest ages are found close to and east of a main strike-slip structure (Bucaramanga fault). This fault has a significant dip-slip component evidenced by an offset of about 10 Ma among the AHe ages across the fault. The main rivers draining the northern EC flow parallel to the main tectonic structures and locally cut across them. The analysis of river longitudinal profiles reveal transient features such as knickpoint not related to lithological or structural contrast. Channel slope and chi analysis suggest a river capture event possibly influenced by the crustal structures. Wind gaps with matching Pleistocene fluvial deposits in addition to river elbows appear to confirm a drainage network reorganization phase given by fluvial piracy.

  3. Uplifting developing communities through sustained technology transfer

    CSIR Research Space (South Africa)

    Mashiri, M


    Full Text Available are considered pivotal for the successful performance and adoption of technologies. A final conclusion is also evident - in order to ensure sustained impact from technology transfer and adoption activities, the ultimate metric is participation as encapsulated...

  4. CDS User survey

    CERN Multimedia

    CERN Document Service


      The CERN Document Server is launching a user survey in order to collect information relative to its search engine, submission interfaces, collaborative features and content organisation. With the view of re-shaping its collections and interfaces and to better integrate with the new INSPIRE platform that serves all HEP literature, CERN Document Server team invites you to take part in the survey. Your input is essential to provide us with useful information before setting up the new service and improve your interactions with CDS. Thanks for participating !  

  5. Lupus Alma Disk Survey (United States)

    Ansdell, Megan


    We present the first unbiased ALMA survey of both dust and gas in a large sample of protoplanetary disks. We surveyed 100 sources in the nearby (150-200 pc), young (1-2 Myr) Lupus region to constrain M_dust to 2 M_Mars and M_gas to 1 M_Jup. Most disks have masses < MMSN and gas-to-dust ratios < ISM. Such rapid gas depletion may explain the prevalence of super-Earths in the exoplanet population.

  6. DSM-5 field survey

    DEFF Research Database (Denmark)

    Lochner, Christine; Grant, Jon E; Odlaug, Brian Lawrence


    Pathologic skin picking (skin picking disorder [SPD]) is a prevalent and disabling condition, which has received increasing study. It is timely to consider including SPD in DSM-5. The aim of this field survey was to investigate possible diagnostic criteria for SPD.......Pathologic skin picking (skin picking disorder [SPD]) is a prevalent and disabling condition, which has received increasing study. It is timely to consider including SPD in DSM-5. The aim of this field survey was to investigate possible diagnostic criteria for SPD....

  7. On-line survey method


    Dvornáková, Táňa


    Thesis deals with modern ways of surveys using advancing information technology and internet which makes surveys using web applications more effective. After a short review of public opinion history the summary of principal czech and forign survey organizations engaged in determination of survey rules are presented. Thesis follows with description of classic and modern data collecting methods. Main attention is devoted to on-line survey method. The description of method, possibilities of real...

  8. Membership Survey Results

    Directory of Open Access Journals (Sweden)

    Dennis M Bowie


    Full Text Available In an effort to gather feedback from Canadian Thoracic Society (CTS members, the Executive sent out a survey to the membership and received replies from approximately one-third of the membership. This was an attempt to look at the role of the CTS and what the members wanted from the CTS.


    National Aeronautics and Space Administration — The Seven-color Asteroid Survey(SCAS) consists of photometry in seven filters from 0.9 to 2.3 microns, of a total of 126 asteroids of types S, K, and M.

  10. A call for surveys

    DEFF Research Database (Denmark)

    Bernstein, Philip A.; Jensen, Christian S.; Tan, Kian-Lee


    The database field is experiencing an increasing need for survey papers. We call on more researchers to set aside time for this important writing activity. The database field is growing in population, scope of topics covered, and the number of papers published. Each year, thousands of new papers ...

  11. Questions for Surveys (United States)

    Schaeffer, Nora Cate; Dykema, Jennifer


    We begin with a look back at the field to identify themes of recent research that we expect to continue to occupy researchers in the future. As part of this overview, we characterize the themes and topics examined in research about measurement and survey questions published in Public Opinion Quarterly in the past decade. We then characterize the field more broadly by highlighting topics that we expect to continue or to grow in importance, including the relationship between survey questions and the total survey error perspective, cognitive versus interactional approaches, interviewing practices, mode and technology, visual aspects of question design, and culture. Considering avenues for future research, we advocate for a decision-oriented framework for thinking about survey questions and their characteristics. The approach we propose distinguishes among various aspects of question characteristics, including question topic, question type and response dimension, conceptualization and operationalization of the target object, question structure, question form, response categories, question implementation, and question wording. Thinking about question characteristics more systematically would allow study designs to take into account relationships among these characteristics and identify gaps in current knowledge. PMID:24970951

  12. Environmental Technician Survey. (United States)

    Lexington Community Coll., KY. Office of Institutional Research.

    In April 1995, Lexington Community College (LCC), in Kentucky, conducted a survey to gather information about employment trends and educational needs in the environmental technician field. The researchers defined environmental technicians as those who implement federal or state environmental requirements, monitor or sample the environment, audit…


    DEFF Research Database (Denmark)

    Persson, H Thomas R; Rakar, Fredrik

    This report is based on a survey sent to 150 representatives of social enterprises in Sweden, out of which 47 responded. Despite not being statistically representative due to the low response rate and the fact that Sweden lacks reliable data on the number of Swedish enterprises, according to the ...

  14. Community Survey 2015 (United States)

    Town of Chapel Hill, North Carolina — This is the 2015 Town of Chapel Hill Community Survey.Using a scale of 1 to 5 where 5 means “Very Satisfied” and 1 means “Very Dissatisfied,” residents were asked...

  15. Surveying Lab II site

    CERN Document Server


    The network of survey reference points on the Lab II site was extended to meet the geodetic needs of the SPS and its North Experimental Area. The work was greatly eased by a geodolite, a measuring instrument on loan from the Fermi Laboratory, which uses a modulated laser beam. (See CERN Courier 14 (1974) p. 247.)

  16. Computational Sociolinguistics: A Survey

    NARCIS (Netherlands)

    Nguyen, Dong-Phuong; Doğruöz, A. Seza; Rosé, Carolyn P.; de Jong, Franciska M.G.

    Language is a social phenomenon and variation is inherent to its social nature. Recently, there has been a surge of interest within the computational linguistics (CL) community in the social dimension of language. In this article we present a survey of the emerging field of “computational

  17. Questions for Online Surveys (United States)

    Ritter, Lois A., Ed.; Sue, Valerie M., Ed.


    The primary function of an evaluation is often to assess the degree of success of a program or to collect information that may be used to improve a program, product, or service. To meet an evaluation's goals and objectives by using an online survey, it is imperative that the questionnaire contain valid and reliable items asked about specific…

  18. ATSDR Marines Health Survey

    Centers for Disease Control (CDC) Podcasts


    This podcast gives an overview of the health survey ATSDR is conducting of more than 300,000 people who lived or worked at Camp Lejeune or Camp Pendleton in the 1970s and 1980s.  Created: 8/30/2011 by Agency for Toxic Substances and Disease Registry (ATSDR).   Date Released: 8/30/2011.

  19. Survey of Testing Practices. (United States)

    Malarkey, Cynthia J.; Aiken, Lewis R.

    The Survey of Testing Practices was administered to 470 undergraduate students at Pepperdine University and the Univesity of California Los Angeles. The items concerned testing practices in three or four classes taken the previous term: type of test, test administration, class size, procedures for returning tests, test difficulty, and observed…

  20. Refraction corrections for surveying (United States)

    Lear, W. M.


    Optical measurements of range and elevation angles are distorted by refraction of Earth's atmosphere. Theoretical discussion of effect, along with equations for determining exact range and elevation corrections, is presented in report. Potentially useful in optical site surveying and related applications, analysis is easily programmed on pocket calculator. Input to equation is measured range and measured elevation; output is true range and true elevation.

  1. 2007 Global Energy Survey

    Energy Technology Data Exchange (ETDEWEB)

    Lauzon, Jean-Claude; Preng, Richard; Sutton, Bob; Pavlovic, Bojan


    The World Energy Council (WEC), in partnership with Korn/Ferry International undertook a survey focussing on the topic ''Tackling the Three S's: Sustainability, Security and Strategy.'' More than 50 senior executives from the world's leading energy companies and their strategic suppliers were interviewed by Korn/Ferry International.

  2. Surveys and Benchmarks (United States)

    Bers, Trudy


    Surveys and benchmarks continue to grow in importance for community colleges in response to several factors. One is the press for accountability, that is, for colleges to report the outcomes of their programs and services to demonstrate their quality and prudent use of resources, primarily to external constituents and governing boards at the state…

  3. An Astronomical Misconceptions Survey (United States)

    LoPresto, Michael C.; Murrell, Steven R.


    Misconceptions that students bring with them to the introductory science classroom plague every area of science and are especially prevalent in astronomy. One way to identify and possibly dispel some of these misconceptions is through the use of a misconceptions survey. The following is a report on the development, implementation, and some early…

  4. Twenty-Sixth Annual Report of the Director of the United States Geological Survey, 1904-1905 (United States)

    Walcott, Charles D.


    . Arrangements for cooperation in geologic work were made with five States, the total amount contributed by them being about \\$8,000, and arrangements for cooperative topographic surveys were made with eleven States, the amount available for such surveys being thus increased by more than \\$100,000.Reclamation serviceThe work of the Reclamation Service during the last fiscal year was advanced as rapidly as was thought consistent with thoroughness and accuracy. Actual construction is now in progress on eight projects, as follows : Salt River, Arizona; Truckee-Carson, Nevada; Hondo, New Mexico ; Uncompahgre Valley, Colorado; Minidoka, Idaho; Belle Fourche, South Dakota ; North Platte, Wyoming and Nebraska ; and Shoshone, Wyoming. Proposals were received for work on the Laguna dam, Yuma project, California and Arizona; Huntley project, Montana, and the Fort Buford project, North Dakota and Montana. In several other States operations are at a point where advertisements for bids only await the removal of certain legal obstacles, the settlement of international difficulties, or the termination of delays on the part of local organizations or individuals.The organization of the body of men constituting the personnel of the Reclamation Service, whose field of operations covers so large a territory, though necessarily difficult, has been satisfactorily accomplished, and precedents have been established along approved lines. The general allotment of funds has been made with a view to the greatest benefit to the greatest number, and from the broad standpoint of the welfare of the country as a whole.One of the important features in the evolution of the irrigation work is the development of power, which the numerous dams and, drops in canals make possible. Plans were made to transmit the power being developed in many sections of the arid regions, by means of electricity, to points more or less distant, there to be used for raising underground waters, pumping waters lying above the line of

  5. Paleoenvironmental Change in the Holocene Sediments of Lake Maruwan Ooike on the Rundvagshetta, Soya Coast, Antarctica-The history of the Regression of the Ice Sheet and Uplift of Soya Coast- (United States)

    Seto, K.; Imura, S.; Moriwaki, K.; Miura, H.


    Holocene marine sediments including the marine molluscan fossils are distributed on the ice-free area of Soya Coast, Antarctica. These sediments are exposed around the freshwater Lake Maruwan Ooike on the Rundvagshetta area. Therefore, we can easily estimate the period of marine environment in the history of this lake. To clarify the paleoenvironmental change in Lake Maruwan Ooike, we carried out the coring used by 2m hand-pushing piston corer. We were able to get the good core. Coring site is located at the north part of lake, which the water depth is 9.8m. Core of 187cm is recovered at this site. The purpose of this study is to clarify the paleoenvironmental change of Lake Maruwan Ooike, and to discuss about the history of the regression of the ice sheet and uplift of Soya Coast. Sediment core (Mw-4 core) is divided to 4 sedimentary unit based on sediment facies. Unit I (0-60cm) consist of laminated silt with cyanobacteria and moss. Unit II (60-68cm) consist of laminated cyanobacterial deposits. In this unit, total organic carbon content (10-15%) is higher than other unit. Unit III (68-150cm) is massive diatomaceous mud including marine benthic foraminifer. Unit IV (150-187cm) is laminated diatomaceous mud. The 14C AMS dating performed using by the organic carbon in sediment at 6 horizon. Calculating from the sedimentation rate and the 14C AMS dating, the boundary age between Unit I and II is estimated with 2900 yr.B.P., and II and III is estimated with 3650 yr.B.P. Unit III and IV show marine environment from the occurrence of benthic foraminifera, Trochammina antarctica and so on. Unit II is estimated the salt lake condition from cyanobacterial flora and high total sulfur content. Unit I is the fresh water lake condition with cyanobacteria and moss flora. Inflow of melt water of ice sheet started from the upper part of unit II, and two-layer structure is formed to salt lake during this unit. The age of change from marine to fresh water environment is estimated

  6. Field Report - Consumer Survey

    DEFF Research Database (Denmark)

    Nielsen, Kristian S.; Gwozdz, Wencke

    The present report outlines the purpose, scope, and methodology of a recently conducted four-country consumer survey that explored sustainable clothing consumption. The report also presents a sample of the descriptive findings from the survey (see Gwozdz, Nielsen & Müller, 2017 for further results...... foundation for upcoming deliverables relating to quality of life, acceptance of new business models, and consumer policy recommendations. The results presented in the report relate, specifically, to consumers’ general clothing consumption patterns, acceptance of new business models, and environmental...... purchasing outlets, and acceptance of new business models. Polish and American consumers purchased the most clothing items. Polish consumers also reported the lowest expenditures on clothing, whereas German consumers reported the highest expenditures. Only a limited proportion of consumers had previously...

  7. Global risks survey (United States)

    Showstack, Randy


    The top five risks facing the globe over the next decade, in order of the likelihood of their occurring, are severe income disparity, chronic fiscal imbalance, rising greenhouse gas emissions, water supply crises, and the mismanagement of population aging. That is according to a survey of more than 1000 experts from industry, government, academia, and civil society, presented in the World Economic Forum's Global Risks 2013 report that was issued on 8 January.

  8. Mescaline: a survey. (United States)

    Schwartz, R H


    The hallucinogen mescaline is found in the peyote and San Pedro cacti, which are prevalent in Mexico and the southwestern United States. In a survey of middle-class, predominantly white adolescents in a drug treatment facility, 18 percent of the respondents indicated that they had taken mescaline. Much of the purported mescaline was probably another hallucinogen, usually LSD. The effects of equipotent doses of mescaline and LSD are almost indistinguishable.

  9. Distributed Systems Technology Survey. (United States)


    S-106 WMh IN7 Distributed Systems Technology Survey Eric C. Cooper Aooousion For DTUC TAIB 1hanUMMOMOd 03 .Tustrifitles AVailability Codes T I F.E .CT...should be connected redundantly, so that there we several paths or routs between any two nodes. In message, swiching , Individuial messages we routed...ADDRESS (City. State and ZIP Cod) -7b. ADDRESS (City. State and ZIP Code ) CARENGIE-HELLON UNIVERSITY ESD/XRSI PITTSBURGH, PA 15213 HANSCOM AIR FORCE

  10. Reinforcement Learning: A Survey


    Kaelbling, L. P.; Littman, M. L.; Moore, A. W.


    This paper surveys the field of reinforcement learning from a computer-science perspective. It is written to be accessible to researchers familiar with machine learning. Both the historical basis of the field and a broad selection of current work are summarized. Reinforcement learning is the problem faced by an agent that learns behavior through trial-and-error interactions with a dynamic environment. The work described here has a resemblance to work in psychology, but differs considerably in...

  11. Qatar Exoplanet Survey

    DEFF Research Database (Denmark)

    Alsubai, Khalid; Mislis, Dimitris; Tsvetanov, Zlatan I.


    We report the discovery of Qatar-3b, Qatar-4b, and Qatar-5b, three new transiting planets identified by the Qatar Exoplanet Survey. The three planets belong to the hot Jupiter family, with orbital periods of PQ3b=2.50792 days, PQ4b=1.80539 days, and PQ5b=2.87923 days. Follow-up spectroscopic obse...... (M > 4 MJ)....

  12. The WFCAM Transit Survey

    Directory of Open Access Journals (Sweden)

    Hodgkin S.


    Full Text Available The WFCAM Transit Survey (WTS has been obtaining data on the United Kingdom Infrared Telescope since 2007. The WTS targets about 8,000 M dwarfs over several square degrees of sky, and aims to find low-mass eclipsing binaries and planets, down to the size of the Earth, transiting M dwarf stars with periods up to a few days.

  13. Game engines: a survey


    A. Andrade


    Due to hardware limitations at the origin of the video game industry, each new game was generally coded from the ground up. Years later, from the evolution of hardware and the need for quick game development cycles, spawned the concept of game engine. A game engine is a reusable software layer allowing the separation of common game concepts from the game assets (levels, graphics, etc.). This paper surveys fourteen different game engines relevant today, ranging from the industry-level to the n...

  14. Robotic and Survey Telescopes (United States)

    Woźniak, Przemysław

    Robotic telescopes are revolutionizing the way astronomers collect their dataand conduct sky surveys. This chapter begins with a discussion of principles thatguide the process of designing, constructing, and operating telescopes andobservatories that offer a varying degree of automation, from instruments remotelycontrolled by observers to fully autonomous systems requiring no humansupervision during their normal operations. Emphasis is placed on designtrade-offs involved in building end-to-end systems intended for a wide range ofscience applications. The second part of the chapter contains descriptions ofseveral projects and instruments, both existing and currently under development.It is an attempt to provide a representative selection of actual systems thatillustrates state of the art in technology, as well as important ideas and milestonesin the development of the field. The list of presented instruments spans the fullrange in size starting from small all-sky monitors, through midrange robotic andsurvey telescopes, and finishing with large robotic instruments and surveys.Explosive growth of telescope networking is enabling entirely new modesof interaction between the survey and follow-up observing. Increasingimportance of standardized communication protocols and software is stressed.These developments are driven by the fusion of robotic telescope hardware,massive storage and databases, real-time knowledge extraction, and datacross-correlation on a global scale. The chapter concludes with examplesof major science results enabled by these new technologies and futureprospects.

  15. The Einstein Slew Survey (United States)

    Elvis, Martin; Plummer, David; Schachter, Jonathan; Fabbiano, G.


    A catalog of 819 sources detected in the Einstein IPC Slew Survey of the X-ray sky is presented; 313 of the sources were not previously known as X-ray sources. Typical count rates are 0.1 IPC count/s, roughly equivalent to a flux of 3 x 10 exp -12 ergs/sq cm s. The sources have positional uncertainties of 1.2 arcmin (90 percent confidence) radius, based on a subset of 452 sources identified with previously known pointlike X-ray sources (i.e., extent less than 3 arcmin). Identifications based on a number of existing catalogs of X-ray and optical objects are proposed for 637 of the sources, 78 percent of the survey (within a 3-arcmin error radius) including 133 identifications of new X-ray sources. A public identification data base for the Slew Survey sources will be maintained at CfA, and contributions to this data base are invited.

  16. [Youth health behavior survey]. (United States)

    Meboniia, N M; Sturua, L Z; Chachava, T D; Kalandadze, I L; Merabishvili, Z G


    High-risk behaviours -- smoking, drug use, alcohol use and etc. are the main risk factors of non-communicable diseases and main reasons of morbidity and mortality in many countries of the world. We conducted the "Youth Health Behaviour Survey" among the students in Tbilisi, Mtskheta and Dusheti. The survey included questioning of students (14-17 years old) by modified questionnaire. There were questioned 300 students, 100 in each region. Mtskheta is very close to Tbilisi, it's a peri-urban area; Dusheti is quite far rural area. The survey results show that teenagers both in central and peripheral areas are becoming familiar with alcohol in early ages and using alcohol is several times higher in Tbilisi. In Tbilisi as in Mtskheta and Dusheti students use wine and spirits with same frequency. Smoking is a bit high in Tbilisi and Mtskheta; regular smoking starts at age 13-14, boys are smoking more than girls. Drug use wasn't identified. Sexual intercourse had almost half of boys from Tbilisi and about one third of boys in Mtskheta and Dusheti. Safe sex methods more frequently are used in Tbilisi. Propaganda of healthy life style is essential in supporting healthy youth development. It's very important to set different interventions in different regions of Georgia, to adapt materials to real situation.

  17. Survey report: Eastern Caribbean. (United States)

    Yinger, N


    Over 1 million people live on 8 small islands in the Eastern Caribbean: St. Kitts-Nevis, Montserrat, Grenada, St. Vincent, Antigua, Barbados, St. Lucia, and Dominica. Starting in 1985 the International Planned Parenthood Federation, Western Hemisphere Region has carried out a series of contraceptive prevalence surveys in these countries. Current information is provided by these surveys in the areas of fertility levels and preferences, contraceptive knowledge and use. Also, socioeconomic, historical and demographic background and analysis such as fertility patterns, desire for additional children, and breastfeeding data; contraceptive awareness including family planning methods and sources; contraceptive use by method, source, and timing, satisfaction, and male attitudes are provided in the surveys, but not in the report abstracted here. The total fertility rate (TFR) and the contraceptive prevalence rate (CPR) for the 8 islands are as follows: St. Kitts-Nevis (1984) 2.9 TFR, 40.6 CPR; St. Vincent (1988) 2.9 TFR, 58.3 CPR; Antigua (1988) 1.8 TFR, 52.6 CPR; Barbados (1988) not given, 55.0 CPR; St. Lucia (1988) 3.2 TFR, 47.3 CPR; Dominica (1987) 3.2 TFR, 49.8 CPR. The islands have unusual demographic patterns related to extensive out-migration.

  18. 2012 Global Management Education Graduate Survey. Survey Report (United States)

    Leach, Laura


    Each year for the past 13 years, the Graduate Management Admission Council (GMAC) has conducted a survey of graduate management education students in their final year of business school. The Global Management Education Graduate Survey is distributed to students at participating schools. The survey allows students to express their opinions about…

  19. Global Management Education Graduate Survey, 2011. Survey Report (United States)

    Schoenfeld, Gregg


    Each year for the past 12 years, the Graduate Management Admission Council[R] (GMAC[R]) has conducted a survey of graduate management education students in their final year of business school. This Global Management Education Graduate Survey is distributed to students at participating business schools. The survey allows students to express their…

  20. Aerial gamma ray and magnetic survey: Mississippi and Florida airborne survey, Shreveport quadrangle of Louisiana. Final report

    Energy Technology Data Exchange (ETDEWEB)


    The Shreveport quadrangle of northwestern Louisiana lies intermediate between the axes of the Sabine and Monroe Uplifts in the Gulf Coastal Physiographic Province. Tertiary and Quaternary sediments dominate the exposed sequence, but the region contains a substantial thickness of Mesozoic rocks as well. Examination of available literature shows no known uranium deposits in the quadrangle. Fifty-four groups of uranium samples were defined as anomalies and discussed briefly. None were considered significant, and most appeared to be of cultural origin. Magnetic data appeared to define the shallower portions of the Sabine Uplift quite well. Other structures in the area were not as well defined by the magnetics.