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Sample records for submarine taiwan orogenic

  1. Relationship between sediment provenance of foreland basin and kinematics of orogenic belt in southwestern Taiwan

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    Hsu, Kun-An; Yang, Kenn-Ming; Chien, Chih-Wei; Wu, Leh-chyun

    2017-04-01

    The foreland basin in southwestern Taiwan offers an idealistic example for geologists to study the tectonostratigraphy in the foreland basin development from initial to latest stages. The subsidence analysis indicate that the initial stage of foreland basin development had started in the Mid Pliocene, and the basin went through two rapid subsidence events, along with forebulge moving back-and-forth in the E-W direction during the Late Pliocene to the Pleistocene. Thus, the tectonostratigraphic sequences deposited from the Late Pliocene to the later periods would provide crucial evidences for the relationship between foreland basin and its adjacent orogenic belt. Based on the tectonostratigraphic sequences in the late stage (Upper Pliocene to Pleistocene) of foreland basin development in SW Taiwan, this study aims to explore the mode of interaction between the evolution of foreland basin and kinematics of orogenic belt primarily based on petrofacies analysis. The results of petrofacies analysis were interpreted with the tectonostratigraphic and biostratigraphic frameworks of previous studies to infer the regional and local sediment provenances and transportation modes. The the craton had been the sediment source to the west of the study area in the pre-orogenic period. The maturity of these sediments was high due to slow exhumation rates and long transportation distance. In the initial stage of foreland basin development, the forebulge slowly elevated and started to partially or totally obstruct sediment supplies from the craton. Before the period of NN19 when the forebulge steadily moved westward, the forebulge not only became the barrier of the most continental sediment supplies from the west but also shed a minor amount of detritus into the adjacent area. In addition, regional topographic relief, which was due to syn-orogenic normal faulting during the NN11-15, locally changed the composition and transportation modes of the sediments; the exposed basement of the

  2. Young orogenic gold mineralisation in active collisional mountains, Taiwan

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    Craw, Dave; Upton, Phaedra; Yu, Bing-Sheng; Horton, Travis; Chen, Yue-Gau

    2010-10-01

    Gold-bearing vein systems in the high mountains of Taiwan are part of the youngest tectonic-hydrothermal system on Earth. Tectonic collision initiated in the Pliocene has stacked Eocene-Miocene marine sedimentary rocks to form steep mountains nearly 4 km high. Thinner portions of the sedimentary pile (˜5 km) are currently producing hydrocarbons in a fold and thrust belt, and orogenic gold occurs in quartz veins in thicker parts of the pile (˜10 km) in the Slate Belt that underlies the mountains. Metamorphic fluids (2-5 wt.% NaCl equivalent) are rising from the active greenschist facies metamorphic zone and transporting gold released during rock recrystallisation. Metamorphic fluid flow at the Pingfengshan historic gold mine was focussed in well-defined (4 km3) fracture zones with networks of quartz veins, whereas large surrounding volumes of rock are largely unveined. Gold and arsenopyrite occur in several superimposed vein generations, with ankeritic alteration of host rocks superimposed on chlorite-calcite alteration zones as fluids cooled and became out of equilibrium with the host rocks. Mineralising fluids had δ18O near +10‰, δ13C was between -1‰ and -6‰ and these fluids were in isotopic equilibrium with host rocks at ˜350°C. Ankeritic veins were emplaced in extensional sites in kink fold axial surfaces, formed as the rock mass was transported laterally from compressional to extensional regimes in the orogen. Rapid exhumation (>2 mm/year) of the Slate Belt is causing a widespread shallow conductive thermal anomaly without igneous intrusions. Meteoric water is penetrating into the conductive thermal anomaly to contribute to crustal fluid flow and generate shallow boiling fluids (˜250°C) with fluid temperature greater than rock temperature. The meteoric-hydrothermal system impinges on, but causes only minor dilution of, the gold mineralisation system at depth.

  3. Silica Geothermometry Applications in the Taiwan Orogenic Belt

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    Chia-Mei Liu

    2015-01-01

    Full Text Available The silica concentrations from 130 hot spring measurements were calculated and used to indicate the heat flow distribution in the active Taiwan orgenic belt. The heat flow spatial distribution seems to be controlled by the Taiwan arc-continent collision zone tectonic development. Two abnormally high silica heat flow regions, 160 and 190 mW m-2, are identified in northeastern and southeastern Taiwan, respectively. In northeastern Taiwan, the Chingshui area, the data suggests that the anomalous heat flow distribution may be controlled mainly by hot fluids and faults. The highest heat flow in southeastern Taiwan may be generated by heat advection caused by a rapidly uplifting hot crust with a decreasing mature arc-continent collision zone exhumation rate. In addition, we estimated the exhumation rate in different tectonic zones in Southern Taiwan by applying fission track ages and silica heat flow values. The exhumation rates are 1.33, 1.72 - 3.87, and 0.51 - 1.74 mm yr-1 in the tectonic zones around Taiwan for advanced, initial arc-continent collision and accretionary wedge deformation, respectively.

  4. Seismic site response of submarine slope offshore southwestern Taiwan

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    Jing-Yi Lin

    2018-01-01

    Full Text Available Widely distributed Bottom-Simulating Reflectors (BSRs have been observed in the area offshore of southwestern Taiwan where the active accretionary complex meets with the passive China continental margin. In order to clarify the link between seismic site response and sedimentary properties of submarine slope, we evaluate the response of seafloor sediments in regard to passive dynamic loads. The local site effect produced by shallow marine sediments was characterized by estimating the horizontal-to-vertical (H/V spectral ratios of data recorded by the short-period Ocean Bottom Seismometers (OBSs. The results show that the maximal H/V ratios appeared in the range of 3.66 - 9.28 Hz, suggesting that the fundamental frequency is dominated by the effect related to the very shallow sediments. For most stations, the H/V ratios estimated based on the earthquakes and noise records were characterized by different patterns. Relatively broad H/V pattern was obtained when the signals were extracted from earthquakes. This phenomenon may be related to soil nonlinearity when a stronger motion applies. In comparison with the available geological structures and bulk density distribution obtained from coring experiments, we found a relatively higher fundamental frequency of about 8 - 9 Hz for the more rigid material, such as mud diapir and folding axes. For most of the area along the slope, the fundamental frequency shows a relatively low value, about 6 - 8 Hz. Finally, when a site is characterized by thick or lowest bulk density sedimentary layer, we observed a fundamental frequency lower than 5 Hz, which is the lowest in our assessment.

  5. Petrographic study of the Miocene-Pleistocene sandstone in the Western Foothills, northern Taiwan: implication for the unroofing history of Taiwan orogenic belt

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    Jia-Jhih, Yeh; Wen-Shan, Chen

    2017-04-01

    The Taiwan orogeny belt developed due to the arc-continental collision since about 6 Ma. Plio-Pleistocene foreland basin deposits are eroded from adjacent orogenic belt that provides much information about orogenic tectonics. In this study, sandstone petrography is enabled to trace orogenic exhumation history of the northern Taiwan. It indicates that late Miocene-early Pliocene strata were composed dominantly of monocrystalline quartz and feldspar deriving from the Eurasia continent. Late Pliocene-early Pleistocene sandstone (3.6-2Ma) contains lithic fragments which consist dominantly of sandstone fragments. It suggests that the sediments were derived from sedimentary province (Miocene strata) of the orogenic belt. The middle Pleistocene sandstone (1.5Ma) consists of argillite and metasandstone fragments (Oligocene strata) deriving from low-grade metamorphic province (the Hsuehshan Range). The late Pleistocene sandstone consists of quartzite fragments (Eocene strata) which were derived from metamorphic province (the Hsuehshan Range). The exhumation history of orogenic belt is revealed significant changes from sedimentary to metamorphic provinces during the middle Pleistocene. It suggests that the Hsuehshan Range exposed since middle Pleistocene. Lithic fragments derived from the Taiwan orogenic belt that corresponded with the unroofing history of the northern Hsuehshan Range by apatite and zircon fission track dating (1.2-2.6Ma and 4.6-6.4Ma).

  6. The Keelung Submarine Volcano in the near-shore area of northern Taiwan and its tectonic implication

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    Tsai, Ching-Hui; Hsu, Shu-Kun; Lin, Shiao-Shan; Yang, Tsanyao F.; Wang, Shiou-Ya; Doo, Wen-Bin; Lee, Hsiao-Fen; Lan, Tefang; Huang, Jian-Cheng; Liang, Chin-Wei

    2017-11-01

    The Taiwan mountain belt has been created due to the collision between the Philippine Sea Plate and the Eurasian Plate. Northernmost Taiwan and its offshore area are now under post-collisional collapse. The post-collisional magmatism is distributed around northern Taiwan. Here we first report a submarine volcano, named Keelung Submarine Volcano, existing in the near-shore area of northern Taiwan. The high 3He/4He ratios in the collected seawater samples suggest that the magma of the Keelung Submarine Volcano is derived from a mantle source. Geometrically, both the Keelung Submarine Volcano and the Tatun Volcano Group are situated above the western border of the subducted Philippine Sea Plate and may have a same magma source. Both volcanic areas belong to the northern Taiwan volcanic zone, instead of the Ryukyu volcanic front. The Keelung Submarine Volcano has been rotated clockwise ∼48° after its formation, which implies that the Keelung Submarine Volcano has formed before the Luzon arc collided against northern Taiwan. Consequently, the post-collisional model to explain the formation of the northern Taiwan volcanic zone is questionable. As indicated by numerous shallow earthquakes and persistent emissions of the volcanic gases out of the seafloor around the volcanic cone, the Keelung Submarine Volcano is as active as the Tatun Volcano Group. For the sake of volcanic hazard assessment, it is essential to monitor the activity of the Keelung Submarine Volcano.

  7. The crustal structures from Wuyi-Yunkai orogen to Taiwan orogen: the onshore-offshore wide-angle seismic experiment of TAIGER and ATSEE projects

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    Kuochen, H.; Kuo, N. Y. W.; Wang, C. Y.; Jin, X.; Cai, H. T.; Lin, J. Y.; Wu, F. T.; Yen, H. Y.; Huang, B. S.; Liang, W. T.; Okaya, D. A.; Brown, L. D.

    2015-12-01

    The crustal structure is key information for understanding the tectonic framework and geological evolution in the southeastern China and its adjacent area. In this study, we integrated the data sets from the TAIGER and ATSEE projects to resolve onshore-offshore deep crustal seismic profiles from the Wuyi-Yunkai orogen to the Taiwan orogen in southeastern China. Totally, there are three seismic profiles resolved and the longest profile is 850 km. Unlike 2D and 3D first arrival travel-time tomography from previous studies, we used both refracted and reflected phases (Pg, Pn, PcP, and PmP) to model the crustal structures and the crustal reflectors. 40 shots, 2 earthquakes, and about 1,950 stations were used and 15,319 arrivals were picked among three transects. As a result, the complex crustal evolution since Paleozoic era are shown, which involved the closed Paleozoic rifted basin in central Fujian, the Cenozoic extension due to South China sea opening beneath the coastline of southern Fujian, and the on-going collision of the Taiwan orogen.

  8. Westward advance of the deformation front and evolution of submarine canyons offshore of southwestern Taiwan

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    Han, Wei-Chung; Liu, Char-Shine; Chi, Wu-Cheng; Chen, Liwen; Lin, Che-Chuan; Chen, Song-Chuen

    2017-11-01

    This study analyzes both 2D and 3D seismic images around the Palm Ridge area offshore of southwestern Taiwan to understand how the deformation front shifted westward and how tectonic activities interact with submarine canyon paths in the transition area between the active and passive margins. Palm Ridge is a submarine ridge that developed on the passive China continental margin by down-dip erosion of several tributaries of Penghu Canyon; it extends eastward across the deformation front into the submarine Taiwan accretionary wedge. The presence of proto-thrusts that are located west of the frontal thrust implies that the compressional stress field has advanced westward due to the convergence of the Philippine Sea Plate and Eurasian Plate. Since the deformation front is defined as the location of the most frontal contractional structure, no significant contractional structure should appear west of it. We thus suggest moving the location of the previously mapped deformation front farther west to where the westernmost proto-thrust lies. High-resolution seismic and bathymetric data reveal that the directions of the paleo-submarine canyons run transverse to the present slope dip, while the present submarine canyons head down slope in the study area. We propose that this might be the result of the westward migration of the deformation front that changed the paleo-bathymetry and thus the canyon path directions. The interactions of down-slope processes and active tectonics control the canyon paths in our study area.

  9. Impact of Submarine Geohazards on Organic Carbon Burial Offshore Southwestern Taiwan

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    Su, C. C.; Tsai, P. H.; Liu, J. T.; Hsu, S. K.; Chiu, S. D.

    2015-12-01

    The tectonically active setting and climatic conditions give Taiwan a high exposure to severe natural hazards. After the Pingtung Earthquake and Morakot Typhoon which occurred in 2006 and 2009, the turbidity currents caused a series of submarine cable breaks along the Gaoping and Fangliao Submarine Canyons off SW Taiwan. Large amounts of terrestrial sediments were fast transported bypass the narrow continental shelf and rapidly moved southward through submarine canyons to the deep sea. Two piston cores which were taken from the Tsangyao Ridge and its adjacent area (OR5-1302-2-MT7 and MT6) might shed light on understanding the export of terrestrial organic carbon to the abyss by submarine geo-hazards. The 210Pb profile of MT7 in conjunction with the grain size data indicates the existence of the Pingtung Earthquake and Morakot Typhoon related deposits. The sedimentation rate of these two cores which derived from 210Pb is approximately 0.05 cm/yr. The cores collected from the Gaoping Submarine Canyon, Gaoping Slope and Fangliao Submarine Canyon are used for analyzing TOC, organic C/N and δ13C ratios. The concentrations of total organic carbon are ~0.5%, and C/N rations almost remain between 4 and 8. The high TOC (~1%) and C/N ratio (>10) are observed in the samples with plant debris. The fluctuation of TOC and C/N ratios in near-shore samples is higher than deep sea. In terms of δ13C-values, it progressively decreases with distances from coastal zone to the deep sea. Due to the larger proportions of land-derived organic carbon, the δ13C-values in the surface sediment of upper Gaoping Submarine Canyon, Gaoping Slope, and the turbidite layers at the head of Fangliao Submarine Canyon are lighter. Furthermore, we use the TOC concentrations and δ13C-values to estimate the fractional contributions of terrestrial organic carbon by a simple two component mixing model, and integrate with the 210Pb-derived sediment accumulation rates to evaluate the organic carbon burial

  10. Kinematics of the tectonic blocks and active faults at the post-orogenic stage: Northern Taiwan

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    Rateb, Ashraf; Ching, Kuo-En; Kuo, Chung-Yen; Rau, Ruey-Juin; Chen, Chien-Liang

    2017-11-01

    Northern Taiwan offers a rare opportunity to quantify the rate and style of deformation in the transition zone, from the collision in the southeast, subduction, rifting, to orogenic collapsing in the northwest. The updated GPS velocity field collected from 2002 to 2014 and leveling vertical velocity field from 2004 to 2010 were inverted by a 3-D block model in this study to infer the tectonic block rotations and fault slip rates in reference to the Eurasian plate. Our optimized modeling results show that the clockwise rotation rate of 20.8° ± 2.8°/Myr in the Hualien block is caused by the coupling of the waning arc-continent collision between the Luzon volcanic arc and the Eurasian plate, and the northeastward migration of the block toward the Ryukyu trench. In Ilan domain, the rapid clockwise motion was derived at a rate of 34.9° ± 65.9°/Myr in southern part of the plain. We proposed that the rapid clockwise rotation results from the asymmetry rifting at the southwestward extension of the Okinawa trough. An another new key finding is highlighted in the capability of maximum magnitude ∼6.2 is indicated on the Suao and the Choshui faults in the Ilan plain.

  11. Turbidity Currents, Submarine Landslides and the 2006 Pingtung Earthquake off SW Taiwan

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    Shu-Kun Hsu

    2008-01-01

    Full Text Available Submarine landslides or slumps may generate turbidity currents consisting of mixture of sediment and water. Large and fast-moving turbidity currents can incise and erode continental margins and cause damage to artificial structures such as telecommunication cables on the seafloor. In this study, we report that eleven submarine cables across the Kaoping canyon and Manila trench were broken in sequence from 1500 to 4000 m deep, as a consequence of submarine landslides and turbidity currents associated with the 2006 Pingtung earthquakes offshore SW Taiwan. We have established a full-scale scenario and calculation of the turbidity currents along the Kaoping canyon channel from the middle continental slope to the adjacent deep ocean. Our results show that turbidity current velocities vary downstream ranging from 20 to 3.7 and 5.7 m/s, which demonstrates a positive relationship between turbidity current velocity and bathymetric slope. The violent cable failures happened in this case evidenced the destructive power of the turbidity current to seafloor or underwater facilities that should not be underestimated.

  12. Characteristics and features of the submarine landslides in passive and active margin southwestern offshore Taiwan

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    Yeh, Y. C.

    2016-12-01

    In the past decade, numerous multi-channel seismic surveys as well as near seafloor high resolution geophysical investigations were conducted in order to explore and estimate the reserves of gas hydrate southwestern offshore Taiwan. The previous object was focused on searching substitute energy (i.e. gas hydrate) rather than geo-hazards. However, it is suggested that most of the gas hydrate is generally distributed at slope area southwestern offshore Taiwan, which indicates the slope may be failed when steady state was disturbed by some factors, such as sea level or climate change. In addition, once gas hydrate was dissociated, this may induce submarine landslide that further cause devastated tsunami. Thus, it is of great urgency to investigate potential landslide area, particularly, the hydrate-rich continental slope (active and passive margins) in adjacent to populous city like Kaohsiung. In this study, we collected several high resolution multi-channel seismic data with ten seconds shooting rate and 3.125 meters group interval streamer by using R/V ORI and R/V ORV. The seismic data were processed in conventional data processing strategy: bad trace clean, geometry settings, band-pass filter, de-convolution, surface-related multiple rejection, radon filter, stacking,kirchhoff migration and time to depth conversion. Combine the results obtained from the MCS data and subbottom profiles, two major results could be raised in the active margin as followed: (1) Most of the surface creeping and landslide was occurred shallower than 500 meters in water depth, which should be related to the inter-bedded fluid activities. (2) The landslide distribution is lagly affected by the presence of diaper, suggesting the subsequent mud diapirism may destruct slope stability; (3) The submarine landslide deeper than 800 meters in water depth distributes in the thrust fold area, that is probably referred to active thrusting. In the passive margin, large volume mass transportation

  13. Strain histories from the eastern Central Range of Taiwan: A record of advection through a collisional orogen

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    Mondro, Claire A.; Fisher, Donald; Yeh, En-Chao

    2017-05-01

    In the eastern Central Range of Taiwan there is a regional variation in the orientation of maximum finite stretch across the slate belt, with down-dip maximum stretch found in the western Central Range and along-strike maximum stretch in the eastern Central Range. Incremental strain histories from syntectonic fibers in pyrite pressure shadows indicate a progressive change in extension direction from down dip to along strike during deformation, there is a corresponding temporal variation in stretching direction shown in samples from the eastern edge of the Central Range, a pattern that mimics the regional west-to-east spatial variation. These observed temporal and spatial strain distributions are used to evaluate the kinematics associated with slaty cleavage development during advection through the Taiwan orogenic system. The subduction zone beneath the island of Taiwan is influenced by two types of obliquity that have the potential to generate the observed along-strike stretching. First, the plate motion vector of the Philippine Sea plate relative to the Eurasian plate is slightly oblique to the regional strike of the mountain range, which could result in partitioning of strike slip shearing into the interior of the collision. Second, the north-south Luzon volcanic arc on the Philippine Sea Plate is obliquely oriented relative to the northeast-southwest edge of the Eurasian continental margin, which could result in lateral extrusion of the ductile core of the range. Incremental strain histories in cleavage-parallel samples represent a time-for-space equivalence where the stretching direction is fixed relative to the position within the mountain belt architecture (e.g., the topographic divide), and temporal variations in the eastern central Range reflect lateral advection through the strain field in response to accretionary and erosional fluxes. Incremental strain histories in cleavage perpendicular samples show both clockwise and counter-clockwise rotation of

  14. Internal tides affect benthic community structure in an energetic submarine canyon off SW Taiwan

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    Liao, Jian-Xiang; Chen, Guan-Ming; Chiou, Ming-Da; Jan, Sen; Wei, Chih-Lin

    2017-07-01

    Submarine canyons are major conduits of terrestrial and shelf organic matter, potentially benefiting the seafloor communities in the food-deprived deep sea; however, strong bottom currents driven by internal tides and the potentially frequent turbidity currents triggered by storm surges, river flooding, and earthquakes may negatively impact the benthos. In this study, we investigated the upper Gaoping Submarine Canyon (GPSC), a high-sediment-yield canyon connected to a small mountain river (SMR) off southwest (SW) Taiwan. By contrasting the benthic meiofaunal and macrofaunal communities within and outside the GPSC, we examined how food supplies and disturbance influenced the benthic community assemblages. The benthic communities in the upper GPSC were mainly a nested subset of the adjacent slope assemblages. Several meiofaunal (e.g. ostracods) and macrofaunal taxa (e.g. peracarid crustaceans and mollusks) that typically occurred on the slope were lost from the canyon. The polychaete families switched from diverse feeding guilds on the slope to motile subsurface deposit feeders dominant in the canyon. The diminishing of epibenthic peracarids and proliferation of deep burrowing polychaetes in the GPSC resulted in macrofauna occurring largely within deeper sediment horizons in the canyon than on the slope. The densities and numbers of taxa were depressed with distinct and more variable composition in the canyon than on the adjacent slope. Both the densities and numbers of taxa were negatively influenced by internal tide flushing and positively influenced by food availability; however, the internal tides also negatively influenced the food supplies. While the meiofauna and macrofauna densities were both depressed by the extreme physical conditions in the GPSC, only the macrofaunal densities increased with depth in the canyon, presumably related to increased frequency and intensity of disturbance toward the canyon head. The population densities of meiofauna, on the

  15. Radionuclides as tracer for submarine groundwater discharge (SGD) research at Dapeng Bay in Southern Taiwan

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    Huang, Jun-Chen; Su, Chih-Chieh

    2017-04-01

    Conventionally, river is the most important source for delivering nutrients, such as nitrogen, phosphorus and silicon, and trace elements into the ocean. The issues of land-sea interaction by rivers have been long-tern concerned and studied, on contrary, the pathway and impact through submarine groundwater discharge (SGD) is still unclear and the relevant researches need to be strengthened. The research site, Dapeng Bay, is located at Pingtung County in Southern Taiwan. Dapeng Bay is an bag-shape lagoon with a sand spit serving as the single outlet of the bay. The longshore currents transport sediments which delivered by Donggang and Linbian Rivers deposited at the nearshore and eventually form the semi-enclosed shallow bay. In the Dapeng Bay, there is no river poured into the lagoon and the main sources of freshwater are rainwater, domestic wastewater and fish ponds etc. The tidal driven water exchange between lagoon and ocean is through the sand spit outlet. The purpose of this study is to evaluate the weighting and seasonal change between SGD and riverine input in the Dapeng Bay. The radium isotopes, 223Ra (11.4d), 224Ra (3.7d), 226Ra (1600y), 228Ra (5.7y), were used as tracers for assessing SGD and riverine inputs. Samples were collected by using MnO2-coated fibers for radium isotopes adsorption.

  16. Detrital U-Pb Zircon Dating of the Cenozoic Metamorphic Terrane in Taiwan Orogenic Belt and its Tectonic Implication

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    Tsai, W.; Lee, Y.

    2011-12-01

    The Taiwan orogen resulted from the collision between the Philippine Sea plate and Eurasia plate since 6.5 Ma and comprises four geologic provinces. From east to west, they are the Coastal Range, the Backbone Range, the Hsuehshan Range, and the Western Foothills. The Coastal Range belongs to Philippine Sea plate. The Backbone Range and Hsuehshan Range are metamorphic terrane are composed of Cenozoic metamorphic terrane and pre-Tertianay metamorphic basement. The Cenozoic metamorphic terrane are lack of fossil and cut by several major faults that results in hard to obtain deposition age and stratigraphic correlation relationship. Here we analysis of more than 3000 grains of detrital U-Pb zircon ages to obtain the age spectrum from Eocene to Miocene metamorphic terrane. The major ages of the Eocene strata are less than 500 Ma; on the contrast the Miocene strata have high percentage of 1800 Ma. Instead of older ages (>100Ma) we found several groups of young U-Pb zircon age, ~39 Ma, ~ 44Ma, ~50 Ma in Eocene strata and 22~25 Ma in Miocene strata which are related with Cenozoic magmatism events in continental margin of Eurasia Plate. This young U-Pb zircon ages indicates the strata age should be younger or similar with these ages. The Eocene strata have been cut by several thrust faults and separated into different blocks. The metamorphic grade increases from west to east of the blocks. The U-Pb Zircon ages indicate the deposition age of the Eocene strata are similar (40Ma) but with different metamorphic grade across the major thrust fault that infers that those thrust faults are preexisting normal faults and are reactive as thrust fault during recently deformation. We also found that the major tectonic boundary "Lishan fault" is unconformity rather than faulting relationship.

  17. Current crustal deformation of the Taiwan orogen reassessed by cGPS strain-rate estimation and focal mechanism stress inversion

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    Chen, Sean Kuanhsiang; Wu, Yih-Min; Hsu, Ya-Ju; Chan, Yu-Chang

    2017-07-01

    We study internal deformation of the Taiwan orogen, a young arc-continental collision belt, which the spatial heterogeneity remains unclear. We aim to ascertain heterogeneity of the orogenic crust in depth when specifying general mechanisms of the Taiwan orogeny. To reach this goal, we used updated data of continuous GPS (cGPS) and earthquake focal mechanisms to reassess geodetic strain-rate and seismic stress fields of Taiwan, respectively. We updated the both data sets from 1990 to 2015 to provide large amount of constraints on surficial and internal deformation of the crust for a better understanding. We estimated strain-rate tensors by calculating gradient tensors of cGPS station velocities in horizontal 0.1°-spacing grids via Delaunay triangulation. We determined stress tensors within a given horizontal and vertical grid cell of 0.1° and 10 km, respectively, by employing the spatial and temporal stress inversion. To minimize effects of the 1999 Mw 7.6 Chi-Chi earthquake on trends of the strain and stress, we modified observational possible bias of the cGPS velocities after the earthquake and removed the first 15-month focal mechanisms within the fault rupture zone. We also calculated the Anderson fault parameter (Aϕ) based on stress ratios and rake angles to quantitatively describe tectonic regimes of Taiwan. By examining directions of seismic compressive axes and styles of faulting, our results indicate that internal deformation of the crust is presently heterogeneous in the horizontal and vertical spaces. Directions of the compressive axes are fan-shaped oriented between N10°W and N110°W in the western and mid-eastern Taiwan at the depths of 0-20 km and near parallel to orientations of geodetic compressional axes. The orientations agreed with predominantly reverse faulting in the western Taiwan at the same depth range, implying a brittle deformation regime against the Peikang Basement High. Orientations of the compressive axes most rotated counter

  18. Bioaccumulation of trace metals in the submarine hydrothermal vent crab Xenograpsus testudinatus off Kueishan Island, Taiwan.

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    Peng, Shao-Hung; Hung, Jia-Jang; Hwang, Jiang-Shiou

    2011-01-01

    The concentrations of ten trace metals were determined in the gills, muscles, hepatopancreas, and exoskeleton tissues of Xenograpsus testudinatus that lives around shallow and acidic hydrothermal vents off Kueishan Island, northeastern Taiwan. The analytical results demonstrate that the metal concentrations vary significantly with the type of crab tissue. The concentrations of Al, Cd, Co, Cu, Fe, Ni, and Zn are highest in the gills, whereas the concentration of Mn is highest in the exoskeleton. Cr and Pb concentrations are similar across the different tissues. The enhanced accumulation of most metals in the gills suggests the metal accumulation via the respiration pathway rather than the uptake of food. The results also reveal that the distribution patterns of metals in tissues are similar in the hepatopancreas and muscles, but very different in both the gills and the exoskeleton, perhaps because of the different pathways of metal utilization in the different crab tissues. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Draft Genome Sequence of Methanoculleus sediminis S3FaT, a Hydrogenotrophic Methanogen Isolated from a Submarine Mud Volcano in Taiwan.

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    Chen, Sheng-Chung; Chen, Mei-Fei; Weng, Chieh-Yin; Lai, Mei-Chin; Wu, Sue-Yao

    2016-04-21

    Here, we announce the genome sequence of ITALIC! Methanoculleus sediminisS3Fa(T)(DSM 29354(T)), a strict anaerobic methanoarchaeon, which was isolated from sediments near the submarine mud volcano MV4 located offshore in southwestern Taiwan. The 2.49-Mb genome consists of 2,459 predicted genes, 3 rRNAs, 48 tRNAs, and 1 ncRNA. The sequence of this novel strain may provide more information for species delineation and the roles that this strain plays in the unique marine mud volcano habitat. Copyright © 2016 Chen et al.

  20. Implications from deepwater depositional elements in the fold-and-thrust belt of the remnant ocean basin offshore SW Taiwan

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    Lin, Liang-Fu; Liu, Char-Shine; Chang, Jih-Hshin

    2017-04-01

    The northeastern South China Sea Basin is being closed due to the oblique collision between the Luzon Volcano Arc and the Chinese Continental Margin. The orogen of Taiwan Island situated in the tropical/subtropical zone with a high uplifting rate provides voluminous sediments to the nearby basins. As a remnant ocean basin, the closing basin in offshore southwestern Taiwan has accommodated a large amount of synorogenic sediments. Through multi-channel seismic profiles, several depositional elements in the deepwater fold-and-thrust belt of the lower Gaoping slope have been identified. These sedimentary layers were deposited before deformation and later incorporated into the orogenic wedge. The N-S trend leveed channels developed along the strike of the orogenic wedge and occupied the most area of the lower Gaoping Slope. This channel-levee complex presents the ancient fan which should relate to the Penghu submarine canyon, named "Penghu Turbidite System". In contrast, at the mouth of the middle section of the Gaoping Submarine Canyon, the buried channels trend SW-NE are characterized by massive high amplitude reflection packets (HARPs) which may represent the coarse grain infills. This facies turns to channelized lobes outward that interfinger with the Penghu Turbidite System. Two different characteristics of submarine fans reflect the different natures of Penghu and Gaoping submarine canyons. Since the tectonic convergence approaching, these two canyons rejuvenated and started to erode the aforementioned deposits. The channels become erosional in the fold-and-thrust belt that most of the sediments bypass through the fold-and-thrust belt or spill into the piggyback accommodations. The newly discovered sedimentary records in this study imply how these two sediment dispersal systems work before and after structuring, which is a puzzle for better understanding the sedimentary history of the remnant ocean basin offshore southwestern Taiwan.

  1. Variation of depositional environment during the evolution of deepwater fold-and-thrust belt in the Frontal Ridge area offshore SW Taiwan

    Science.gov (United States)

    Lin, L. F.; Liu, C. S.; Lin, C. C.; Hsu, H. H.; Chang, J. H.; Chen, S. C.; Wang, Y.; Chung, S. H.

    2014-12-01

    The area offshore SW Taiwan is an active margin where the accretionary prism of the Luzon arc-trench system has obliquely overridden the continental margin of the South China Sea (SCS). Located by the Penghu Submarine Canyon, the Frontal Ridge is the westernmost structural relief of the orogenic wedge which is separated from the SCS continental margin by a deformation front. The Penghu submarine canyon, which starts from the China continental shelf and cuts across the fold-and-thrust belt, may plays an important role for transporting orogenic sediments from on shore Taiwan to the deep sea South China Sea basin. In this study, high-resolution seismic data collected in the Frontal Ridge area have been analyzed, a significant variation of stratigraphic architectures with time were identified by detailed analyzing both structural and depositional characteristics. Seismic facies analysis shows that the older parallel strata were eroded and superimposed by a series of lobe-channel-levee complex, interpreted as the fan deposits of the paleo Penghu Submarine Canyon. These deposits were later deformed by a multi-stage frontal thrusting. We propose a model to show how tectonic processes change the depositional environment. During the evolution of fold-and-thrust belt, the slope gradient and sedimentation rate changed. The Frontal Ridge area was at the abyssal plain, and then changed to the continental rise environment. Finally, convergent tectonics changed this area to be part of the orogenic wedge, and frontal fold developed.

  2. Transport and bottom accumulation of fine river sediments under typhoon conditions and associated submarine landslides: case study of the Peinan River, Taiwan

    Science.gov (United States)

    Osadchiev, Alexander; Korotenko, Konstantin; Zavialov, Peter; Chiang, Wen-Son; Liu, Cheng-Chi

    2016-04-01

    A combination of a three-dimensional Eulerian ocean circulation model (POM) and a Lagrangian particle-tracking model (STRiPE) is used to study the fate of fine river sediments discharged by the Peinan River at the south-eastern coast of the Taiwan Island. The composite model is verified against in situ measurements and applied to simulate primary sediment deposition under freshet and typhoon discharge conditions of the Peinan River. It is shown that local wind plays a crucial role in sediment transport and settling at the coastal area through its influence on the river plume dynamics and turbulent mixing in the upper layer. Wind forcing conditions generally determine the location of the sediment deposit area, while its final pattern is defined by coastal circulation as modulated by the geometry of the coast and local bathymetry. In the study, region river-born sediments are deposited to the sea floor mainly in the shallow shelf areas. A significant portion of discharged fine sediments is moved offshore to the deeper ocean where it is further advected and dispersed by strong coastal circulation mainly governed by the Kuroshio Current. The performed numerical experiments showed that sediment accumulation rate under typhoon conditions is about two orders of magnitude greater comparing to freshet condition. Basing on the simulation results, we identified areas of continental shelf and continental slope adjacent to the Peinan River estuary which exhibit high risk of formation of submarine landslides during and shortly after the typhoon events.

  3. Activation of gas bubble emissions indicated by the upward decreasing Lead-210 activity at a submarine mud volcano (TY1) offshore southwestern Taiwan

    Science.gov (United States)

    Hiruta, Akihiro; Yang, Tsanyao Frank; Lin, Saulwood; Su, Chih-Chieh; Chen, Nai-Chen; Chen, Yi-Jyun; Chen, Hsuan-Wen; Yang, Tsung-Han; Huang, Yu-Chun; Wei, Kuo-Yen; Huang, Jyh-Jaan; Chen, Song-Chuen; Song, Sheng-Rong

    2017-11-01

    A submarine mud volcano (MV) known as TY1 is one of the largest conical structures found offshore southwestern Taiwan. Active gas bubble emissions at the flat crest of the mud volcano disperse sediment particles into the water column. Changes in the mud volcanism of TY1 were revealed by radiograph and grain size analysis of the sediment cores. 210Pb geochronology was applied to the near-seafloor sediments to reveal the detailed mud volcanism from the deposition rate. In a 58-cm long sediment core taken from the northern margin of the crest, known as TY1-N.170, the size and frequency of the mud clasts decrease upward. The clasts are smaller than 8 mm above a sediment depth of 34 cm below the sea floor (cmbsf). Sediments between 0 and 19 cmbsf are massive, and particles larger than 2 mm are absent. An enrichment of coarse, silt-sized particles in the massive sediment unit and the restricted distribution of the unit suggest that the massive unit was generated by re-deposition of sediment particles that were dispersed into the water column by gas bubble emission. These characteristics suggest that during the last mud volcanism of TY1, there was a decrease in mud eruption energy, and gas bubble emission became the main activity. In core TY1-S.440, taken from the southern slope, a massive sediment unit enriched with coarse, silt-sized particles, is intercalated between mud breccia structures. This suggests repeated mud breccia flows caused by TY1. The excess 210Pb activity present in the massive sediment unit of TY1-N.170 suggests activation of gas bubble emission. In the massive unit, a decrease in excess 210Pb activity appears upward toward the seafloor. The highest value is 3.1 dpm/g at 19.8 cmbsf (26.4 g/cm2 in cumulative mass); values lower than 1.0 dpm/g are distributed 2.8-6.8 cmbsf (3.6-8.8 g/cm2). The upwardly decreasing trend is opposite that of the reference core from which a reasonable areal sedimentation rate was obtained using a constant-flux constant

  4. Introduction to the special issue on submarine geohazard records and potential seafloor instability

    Directory of Open Access Journals (Sweden)

    Song-Chuen Chen Jia-Jyun Dong

    2018-01-01

    Full Text Available Submarine landslides frequently occur in passive continental margins or active margins (Hampton et al. 1996; Wynn et al. 2000; Mienert et al. 2002; Korup et al. 2007; Twichell et al. 2009; Cukur et al. 2016. Submarine landslides have been studied extensively not only for scientific research but also for submarine geohazards. Submarine landslides could jeopardize marine infrastructures, such as offshore drilling platforms or submarine telecommunication cables, and could even trigger disastrous tsunamis (Bondevik et al. 2005; Harbitz et al. 2006; Hornbach et al. 2007, 2008; Hsu et al. 2008; Su et al. 2012; Tappin et al. 2014; Li et al. 2015. For instance, one disastrous tsunami hitting the coastal area of southwestern Taiwan in 1781 or 1782 was reported (Chen 1830; Hsu 1983; the tsunami event was probably generated by submarine landslides in the offshore area of southwestern Taiwan (Li et al. 2015. Moreover, several submarine landslides triggered by the 2006 Pingtung earthquake have induced turbidity currents off southwest Taiwan and destroyed about 14 submarine telecommunication cables off SW Taiwan (Hsu et al. 2008. The area of southwest Taiwan currently has a dense population (more than 3 million people in total, one deep-water Kaohsiung Port, several tanks of liquefied natural gas and a nuclear power plant on the coast (Fig. 1. Numerous submarine telecommunication cables exist off SW Taiwan. If a considerable tsunami event would hit again the costal area of SW Taiwan, the damage could very serious. Likewise, there are two nuclear power plants on the coast of northern Taiwan (Fig. 2, and the population in northern Taiwan has more than 10 million people. Submarine telecommunication cables also exist off northern Taiwan. In any case, it is important to understand the status of seafloor stability in the offshore areas of SW and NE Taiwan. For that, this special issue of submarine geohazard records and potential seafloor instability is aimed to

  5. Submarine hydrodynamics

    CERN Document Server

    Renilson, Martin

    2015-01-01

    This book adopts a practical approach and presents recent research together with applications in real submarine design and operation. Topics covered include hydrostatics, manoeuvring, resistance and propulsion of submarines. The author briefly reviews basic concepts in ship hydrodynamics and goes on to show how they are applied to submarines, including a look at the use of physical model experiments. The issues associated with manoeuvring in both the horizontal and vertical planes are explained, and readers will discover suggested criteria for stability, along with rudder and hydroplane effectiveness. The book includes a section on appendage design which includes information on sail design, different arrangements of bow planes and alternative stern configurations. Other themes explored in this book include hydro-acoustic performance, the components of resistance and the effect of hull shape. Readers will value the author’s applied experience as well as the empirical expressions that are presented for use a...

  6. Coupled stratigraphic and structural evolution of a glaciated orogenic wedge, offshore St. Elias orogen, Alaska

    Science.gov (United States)

    Worthington, Lindsay L.; Gulick, Sean P. S.; Pavlis, Terry L.

    2010-12-01

    The St. Elias orogen is the result of ˜10 Myr of oblique convergence and flat-slab subduction in the Gulf of Alaska between North America and the Yakutat microplate. Extensive glaciation and a complex tectonic environment make this region a unique case study in which to examine the details of terrane accretion and the possible coupled influence of climate and tectonic drivers on the structural and topographic evolution of an orogenic wedge. Reflection seismic profiles across the offshore Pamplona zone fold-thrust belt, the frontal St. Elias orogenic wedge, provide constraints for quantifying Pleistocene deformation recorded in the glaciomarine Yakataga formation. The total amount of Pleistocene shortening observed varies from ˜3 to 5 mm/yr, compared to the current GPS-derived Yakutat-North America convergence rate across the St. Elias orogen of ˜45 mm/yr. Growth strata and kinematic fold analysis allow comparison of relative timing of fault activity, which reveals temporal and spatial shifting of active deformation during the glacial period: faulting localized adjacent to the coastline and at the current submarine deformation front. The abandoned, currently inactive region is colocated with the major glacial depocenter in the region, the Bering Trough. These observations imply that glacial processes such as sediment loading and focused erosion during advance-retreat cycles has a direct effect on the evolution of individual faults within the Pamplona zone and the overall deformation pattern in the offshore St. Elias margin. This information provides key constraints for understanding how climatic shifts may have affected the evolution of margin architecture during Pleistocene glacial-interglacial periods.

  7. Submarine Medicine Team

    Data.gov (United States)

    Federal Laboratory Consortium — The Submarine Medicine Team conducts basic and applied research on biomedical aspects of submarine and diving environments. It focuses on ways to optimize the health...

  8. Miocene Current-Modified Submarine Fans

    Science.gov (United States)

    Arce Perez, L. E.; Snedden, J.; Fisher, W. L.

    2016-12-01

    In the southwestern Gulf of Mexico, new and newly reprocessed seismic data has revealed a series of large bedforms, with set thicknesses of 130 to 250 meters. These exhibit hummocky, oblique and shingled to parallel seismic clinoform reflections. This seismic package has a paleowater depth of 450 meters. Those shingled seismic reflections in offshore east Mexico are interpreted as contourite drift deposits. These Miocene-age contourites may be related to strong ocean bottom currents that modified submarine fans and transported sediment to the north. Those contourites were identified on older seismic data, but are better imaged and interpreted on this new data. Plans are to map out and investigate the origin and extent of fans and contourites that extends over a large area of the Gulf of Mexico. In the Early Miocene several submarine fans systems were formed by the sediment input related to orogenic activity in Mexico. Submarine fan development persisted into the Middle Miocene due to continued uplift and erosion of the Mexican landmass. Initial, contourites are small and close proximity to the deep-water fan. In the Late Miocene time, contourite drift field reached its maximum extent in the Mexican deepwater area, anchored on its southern end by a submarine mound. This mounded submarine fan is located in the offshore northeast Veracruz and can be linked to increased uplift and erosion of the Trans-Mexican volcanic belt. In the Miocene-Pliocene, the large contourite drift begins to diminish in size and scale and is moribund by the Pliocene, with establishment of oceanic circulation similar to the present day. This research is important to understand more about the Gulf of Mexico and also for the Miocene timeframe that is a key phase in the earth's history. The role of the change in bottom water flow during progressive closure of the equatorial seaway separating North and South America will also be investigated.

  9. Low cost submarine robot

    OpenAIRE

    Ponlachart Chotikarn; Werapong Koedsin; Boonlua Phongdara; Pattara Aiyarak

    2010-01-01

    A submarine robot is a semi-autonomous submarine robot used mainly for marine environmental research. We aim todevelop a low cost, semi-autonomous submarine robot which is able to travel underwater. The robot’s structure was designedand patented using a novel idea of the diving system employing a volume adjustment mechanism to vary the robot’s density.A light weight, flexibility and small structure provided by PVC can be used to construct the torpedo-liked shape robot.Hydraulic seal and O-rin...

  10. Low cost submarine robot

    Directory of Open Access Journals (Sweden)

    Ponlachart Chotikarn

    2010-10-01

    Full Text Available A submarine robot is a semi-autonomous submarine robot used mainly for marine environmental research. We aim todevelop a low cost, semi-autonomous submarine robot which is able to travel underwater. The robot’s structure was designedand patented using a novel idea of the diving system employing a volume adjustment mechanism to vary the robot’s density.A light weight, flexibility and small structure provided by PVC can be used to construct the torpedo-liked shape robot.Hydraulic seal and O-ring rubbers are used to prevent water leaking. This robot is controlled by a wired communicationsystem.

  11. Submarine Salt Karst Terrains

    Directory of Open Access Journals (Sweden)

    Nico Augustin

    2016-06-01

    Full Text Available Karst terrains that develop in bodies of rock salt (taken as mainly of halite, NaCl are special not only for developing in one of the most soluble of all rocks, but also for developing in one of the weakest rocks. Salt is so weak that many surface-piercing salt diapirs extrude slow fountains of salt that that gravity spread downslope over deserts on land and over sea floors. Salt fountains in the deserts of Iran are usually so dry that they flow at only a few cm/yr but the few rain storms a decade so soak and weaken them that they surge at dm/day for a few days. We illustrate the only case where the rates at which different parts of one of the many tens of subaerial salt karst terrains in Iran flows downslope constrains the rates at which its subaerial salt karst terrains form. Normal seawater is only 10% saturated in NaCl. It should therefore be sufficiently aggressive to erode karst terrains into exposures of salt on the thousands of known submarine salt extrusions that have flowed or are still flowing over the floors of hundreds of submarine basins worldwide. However, we know of no attempt to constrain the processes that form submarine salt karst terrains on any of these of submarine salt extrusions. As on land, many potential submarine karst terrains are cloaked by clastic and pelagic sediments that are often hundreds of m thick. Nevertheless, detailed geophysical and bathymetric surveys have already mapped likely submarine salt karst terrains in at least the Gulf of Mexico, and the Red Sea. New images of these two areas are offered as clear evidence of submarine salt dissolution due to sinking or rising aggressive fluids. We suggest that repeated 3D surveys of distinctive features (± fixed seismic reflectors of such terrains could measure any downslope salt flow and thus offer an exceptional opportunity to constrain the rates at which submarine salt karst terrains develop. Such rates are of interest to all salt tectonicians and the many

  12. What threat do turbidity currents and submarine landslides pose to submarine telecommunications cable infrastructure?

    Science.gov (United States)

    Clare, Michael; Pope, Edward; Talling, Peter; Hunt, James; Carter, Lionel

    2016-04-01

    The global economy relies on uninterrupted usage of a network of telecommunication cables on the seafloor. These submarine cables carry ~99% of all trans-oceanic digital data and voice communications traffic worldwide, as they have far greater bandwidth than satellites. Over 9 million SWIFT banks transfers alone were made using these cables in 2004, totalling 7.4 trillion of transactions per day between 208 countries, which grew to 15 million SWIFT bank transactions last year. We outline the challenge of why, how often, and where seafloor cables are broken by natural causes; primarily subsea landslides and sediment flows (turbidity currents and also debris flows and hyperpycnal flows). These slides and flows can be very destructive. As an example, a sediment flow in 1929 travelled up to 19 m/s and broke 11 cables in the NE Atlantic, running out for ~800 km to the abyssal ocean. The 2006 Pingtung earthquake triggered a sediment flow that broke 22 cables offshore Taiwan over a distance of 450 km. Here, we present initial results from the first statistical analysis of a global database of cable breaks and causes. We first investigate the controls on frequency of submarine cable breaks in different environmental and geological settings worldwide. We assess which types of earthquake pose a significant threat to submarine cable networks. Meteorological events, such as hurricanes and typhoons, pose a significant threat to submarine cable networks, so we also discuss the potential impacts of future climate change on the frequency of such hazards. We then go on to ask what are the physical impacts of submarine sediment flows on submerged cables? A striking observation from past cable breaks is sometimes cables remain unbroken, whilst adjacent cables are severed (and record powerful flows travelling at up to 6 m/s). Why are some cables broken, but neighbouring cables remain intact? We provide some explanations for this question, and outline the need for future in

  13. Orogen styles in the East African Orogen: A review of the Neoproterozoic to Cambrian tectonic evolution

    Science.gov (United States)

    Fritz, H.; Abdelsalam, M.; Ali, K. A.; Bingen, B.; Collins, A. S.; Fowler, A. R.; Ghebreab, W.; Hauzenberger, C. A.; Johnson, P. R.; Kusky, T. M.; Macey, P.; Muhongo, S.; Stern, R. J.; Viola, G.

    2013-10-01

    The East African Orogen, extending from southern Israel, Sinai and Jordan in the north to Mozambique and Madagascar in the south, is the world´s largest Neoproterozoic to Cambrian orogenic complex. It comprises a collage of individual oceanic domains and continental fragments between the Archean Sahara-Congo-Kalahari Cratons in the west and Neoproterozoic India in the east. Orogen consolidation was achieved during distinct phases of orogeny between ∼850 and 550 Ma. The northern part of the orogen, the Arabian-Nubian Shield, is predominantly juvenile Neoproterozoic crust that formed in and adjacent to the Mozambique Ocean. The ocean closed during a protracted period of island-arc and microcontinent accretion between ∼850 and 620 Ma. To the south of the Arabian Nubian Shield, the Eastern Granulite-Cabo Delgado Nappe Complex of southern Kenya, Tanzania and Mozambique was an extended crust that formed adjacent to theMozambique Ocean and experienced a ∼650-620 Ma granulite-facies metamorphism. Completion of the nappe assembly around 620 Ma is defined as the East African Orogeny and was related to closure of the Mozambique Ocean. Oceans persisted after 620 Ma between East Antarctica, India, southern parts of the Congo-Tanzania-Bangweulu Cratons and the Zimbabwe-Kalahari Craton. They closed during the ∼600-500 Ma Kuungan or Malagasy Orogeny, a tectonothermal event that affected large portions of southern Tanzania, Zambia, Malawi, Mozambique, Madagascar and Antarctica. The East African and Kuungan Orogenies were followed by phases of post-orogenic extension. Early ∼600-550 Ma extension is recorded in the Arabian-Nubian Shield and the Eastern Granulite-Cabo Delgado Nappe Complex. Later ∼550-480 Ma extension affected Mozambique and southern Madagascar. Both extension phases, although diachronous,are interpreted as the result of lithospheric delamination. Along the strike of the East African Orogen, different geodynamic settings resulted in the evolution of

  14. SCICEX: Submarine Arctic Science Program

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Submarine Arctic Science Program, SCICEX, is a federal interagency collaboration among the operational Navy, research agencies, and the marine research community...

  15. The Submarine, 1776-1918

    National Research Council Canada - National Science Library

    Uhlig, Frank

    2004-01-01

    When, on 11 April 1900, the U.S. Navy thought the Holland, named for its designer, that little submarine joined a fleet consisting of two armored cruisers, six monitors, seven first and second-class battleships, and seventeen each...

  16. The Enemy Below - The Global Diffusion of Submarines and Related Technology

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, K G

    2002-09-05

    The end of the Cold War seemed to create a more peaceful international environment. September 11 reminded us of the dangers of complacency. Indeed, even before September 11 US forces had intervened in a number of wars and crises, including Panama, the Persian Gulf War, Somalia, Rwanda, Bosnia, Kosovo, several Taiwan Straits crises, the North Korea nuclear weapons crisis, and most recently Afghanistan. US ability to intervene in remote areas of the world is often dependent on the Navy's ability to project power ashore. As a result, US ability to influence events in crisis situations, especially between or among nuclear powers, may become more difficult along with our ability to conduct littoral warfare. Although the numbers of potentially hostile submarines have declined with the end of the Cold War, US anti-submarine warfare capabilities have also declined. Moreover, foreign submarines and related technologies are likely to diffuse globally. New technologies like Air Independent Propulsion (AIP), improved weapons and sensors will make conventional submarines more dangerous, and the spread of nuclear submarines even to a few more countries raise political, military, environmental, and safety concerns. Submarines are one of the key weapon systems used alone or in combination with other weapon systems such as coastal defense missiles, aircraft, and other sea-based missile platforms to deny US ability to project power ashore, Thus, other countries who wish to deny the US the ability to interfere with their regional or even global ambitions may emphasize the acquisition and/or development of submarines. As the world become more multipolar over the longer term, as the Chinese believe it will, countries such as Russia, China. etc., may be able to acquire the submarine capabilities to challenge us not just regionally, but in blue waters. To the extent that our alliance relationships require US naval access or superiority to sustain them, then our erstwhile friendly

  17. Submarine Information Organization and Prioritization and Submarine Officer of the Deck Experience

    Science.gov (United States)

    2004-07-12

    The Submarine Review, 58-64. Shobe, K. (2002, May). Information organization and modeling of the submarine officer of the deck and sonar operator...Technical Report 01Oct00 - 31Sep02 SUBMARINE INFORMATION ORGANIZATION AND PRIORITIZATION AND SUBMARINE OFFICER OF THE DECK EXPERIENCE 51001 1) Katharine K

  18. Enhancing Submarine Operational Relevance: A Leadership Challenge

    National Research Council Canada - National Science Library

    Daigle, Jr, Michael J

    2008-01-01

    .... This vision of submarine operations must change. As the military continues to shift to operations focused on joint capabilities, the submarine force must break from the closed, protective, and risk averse culture of its past and push forward...

  19. Submarine silicic volcanism: Processes and products

    Digital Repository Service at National Institute of Oceanography (India)

    Kalangutkar, N.G.; Iyer, S.D.

    The occurrence of submarine silicic volcanics is rare at the mid-oceanic ridges, abyssal depths, seamounts and fracture zones. Hydrothermal processes are active in submarine silicic environments and are associated with host ores of Cu, Au, Ag, Pb...

  20. North American Submarine Cable Association (NASCA) Submarine Cables

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data show the locations of in-service and out-of-service submarine cables that are owned by members of NASCA and located in U.S. territorial waters. More...

  1. Submarine geothermal resources

    Science.gov (United States)

    Williams, D.L.

    1976-01-01

    Approximately 20% of the earth's heat loss (or 2 ?? 1012 cal/s) is released through 1% of the earth's surface area and takes the form of hydrothermal discharge from young (Pleistocene or younger) rocks adjacent to active seafloor-spreading centers and submarine volcanic areas. This amount is roughly equivalent to man's present gross energy consumption rate. A sub-seafloor geothermal reservoir, to be exploitable under future economic conditions, will have to be hot, porous, permeable, large, shallow, and near an energy-deficient, populated land mass. Furthermore, the energy must be recoverable using technology achievable at a competitive cost and numerous environmental, legal and institutional problems will have to be overcome. The highest-temperature reservoirs should be found adjacent to the zones of the seafloor extension or volcanism that are subject to high sedimentation rates. The relatively impermeable sediments reduce hydrothermal-discharge flow rates, forcing the heat to be either conducted away or released by high-temperature fluids, both of which lead to reservoir temperatures that can exceed 300??C. There is evidence that the oceanic crust is quite permeable and porous and that it was amenable to deep (3-5 km) penetration by seawater at least some time in the early stages of its evolution. Most of the heat escapes far from land, but there are notable exceptions. For example, in parts of the Gulf of California, thermal gradients in the bottom sediments exceed 1??C/m. In the coastal areas of the Gulf of California, where electricity and fresh water are at a premium, this potential resource lies in shallow water (< 200 m) and within sight of land. Other interesting areas include the Sea of Japan, the Sea of Okhotsk and the Andaman Sea along the margins of the western Pacific, the Tyrrhenian Sea west of Italy, and the southern California borderland and west flank of the Juan de Fuca Ridge off the west coast of the United States. Many questions remain to be

  2. Submarine canyons off Madras Coast

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

    Submarine canyons off the coast of Madras, Tamil Nadu, India were studied during cruise of @iINS Kistna@@ as part of the IIOE programme They consist of hill-like projections and V-shaped valleys Their other features are also reported...

  3. Flow of ultra-hot Precambrian orogens and the making of crustal layering in Phanerozoic orogenic plateaux

    Science.gov (United States)

    Chardon, Dominique; Gapais, Denis; Cagnard, Florence; Jayananda, Mudlappa; Peucat, Jean-Jacques

    2010-05-01

    Reassessment of structural / metamorphic properties of ultra-hot Precambrian orogens and shortening of model weak lithospheres support a syn-convergence flow mode on an orogen scale, with a large component of horizontal finite elongation parallel to the orogen. This orogen-scale flow mode combines distributed shortening, gravity-driven flow, lateral escape, and three-dimensional mass redistribution of buried supracrustal rocks, magmas and migmatites in a thick fluid lower crust. This combination preserves a nearly flat surface and Moho. The upper crust maintains a nearly constant thickness by real-time erosion and near-field clastic sedimentation and by ablation at its base by burial of pop-downs into the lower crust. Steady state regime of these orogens is allowed by activation of an attachment layer that maintains kinematic compatibility between the thin and dominantly plastic upper crust and a thick "water bed" of lower crust. Because very thin lithospheres of orogenic plateaux and Precambrian hot orogens have similar thermomechanical structures, bulk orogenic flow comparable to that governing Precambrian hot orogens should actually operate through today's orogenic plateaux as well. Thus, syn-convergence flow fabrics documented on exposed crustal sections of ancient hot orogens that have not undergone collapse may be used to infer the nature of flow fabrics that are imaged by geophysical techniques beneath orogenic plateaux. We provide a detailed geological perspective on syn-convergence crustal flow in relation to magma emplacement and partial melting on a wide oblique crustal transition of the Neoarchean ultra-hot orogen of Southern India. We document sub-horizontal bulk longitudinal flow of the partially molten lower crust over a protracted period of 60 Ma. Bulk flow results from the interplay of (1) pervasive longitudinal transtensional flow of the partially molten crust, (2) longitudinal coaxial flow on flat fabrics in early plutons, (3) distributed, orogen

  4. Erosion rates across space and timescales from a multi-proxy study of rivers of eastern Taiwan

    Science.gov (United States)

    Fellin, Maria Giuditta; Chen, Chia-Yu; Willett, Sean D.; Christl, Marcus; Chen, Yue-Gau

    2017-10-01

    We derive erosion rates from detrital zircon fission-track ages and cosmogenic nuclide concentrations from sediments from the modern rivers of eastern Taiwan in order to investigate how surface erosional processes vary in space and time across the young arc-continent collisional orogen of Taiwan. Taiwan is characterized by rapid rates of exhumation, a fluvial and landslide-dominated landscape, high seismicity, high relief and frequent typhoons. The obliquity between the convergence direction and the trend of the plate boundary provides a gradient in uplift and variations in longevity of orogenic activity with a young, immature orogen in the south, a mature orogen in central and northern Taiwan, and perhaps even the cessation of orogeny in the far north. The modern zircon fission-track detrital record is consistent with basement ages that show that much of the orogen is eroding at high rates with basin-wide mean zircon fission-track cooling ages as young as 0.9 Ma. The erosion rates derived from concentrations of cosmogenic nuclides (10Be) provide erosion rates averaged over much shorter timescales, but these two proxies provide estimates of erosion rates that are within error of each other across most of the collisional belt. Erosion rates are lowest in the immature zone of the orogen (process and that landscape evolution is reacting primarily to tectonic forcing, fast enough to keep the landscape in a state of quasi-equilibrium where erosion rates and rock uplift rates are nearly equal. We find no measurable effects due to rock erodibility or precipitation rate, but if these parameters co-vary with tectonic uplift rate, our data could not resolve the influence of each.

  5. SCICEX: Submarine Arctic Science Program, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Submarine Arctic Science Program, SCICEX, is a federal interagency collaboration among the operational Navy, research agencies, and the marine research community...

  6. Erosional Reduction of an Orogenic Wedge: Structural Response to Neogene Climate Change within the St. Elias Orogen, Alaska

    Science.gov (United States)

    Berger, A. L.; Spotila, J. A.; Chapman, J. B.; Pavlis, T. L.; Enkelmann, E.; Buscher, J. T.

    2007-12-01

    The kinematics and architecture of orogenic systems may be heavily influenced by climate, but little research has focused on the long term effects of glacial erosion on orogenesis. Apatite and zircon (U-Th)/He thermochronometry on >75 bedrock samples across the St. Elias orogen, one of the best examples of a glaciated orogenic wedge, is the basis for a new kinematic model and demonstrates an association between glacial denudation and orogenic architecture. The spatial pattern of low temperature cooling indicates that exhumation and deformation are focused within a thin-skinned fold and thrust belt on the windward flank, whereas the leeward flank of the orogen functions as a deformational backstop. A previously unrecognized structure beneath the Bagley ice field must separate these domains with south-side-up motion. We propose this structure is a backthrust making the orogen doubly-vergent. Suggestive of accelerated backthrust motion in response to climate change, cooling rates within the hanging wall block and across the entire windward flank of the orogen accelerated ten-fold coeval with enhanced glaciation. As backthrust motion increased, glacial unroofing also coincided with a regional shift in deformation away from prominent forethrusts including the North American-Yakutat terrane suture (Chugach St. Elias fault) and the seaward deformation front (Pamplona zone). Across the windward flank of the orogen, exhumation, at rates of up to 5 mm/yr, is focused within a narrow zone, where the glacial equilibrium line altitude (ELA) intersects the orogenic wedge. This zone of rapid exhumation, not present prior to the onset of enhanced glaciation, cuts across the structural trend of the orogen and is more narrowly focused than orographic precipitation. Accelerated denudation at the ELA thus appears to have redistributed strain along a series of forethrusts that lie at the zone of heaviest glacial flux, while the backthrust progressively truncates the southward

  7. Submarines, spacecraft and exhaled breath.

    Science.gov (United States)

    Pleil, Joachim D; Hansel, Armin

    2012-03-01

    Foreword The International Association of Breath Research (IABR) meetings are an eclectic gathering of researchers in the medical, environmental and instrumentation fields; our focus is on human health as assessed by the measurement and interpretation of trace chemicals in human exhaled breath. What may have escaped our notice is a complementary field of research that explores the creation and maintenance of artificial atmospheres practised by the submarine air monitoring and air purification (SAMAP) community. SAMAP is comprised of manufacturers, researchers and medical professionals dealing with the engineering and instrumentation to support human life in submarines and spacecraft (including shuttlecraft and manned rockets, high-altitude aircraft, and the International Space Station (ISS)). Here, the immediate concerns are short-term survival and long-term health in fairly confined environments where one cannot simply 'open the window' for fresh air. As such, one of the main concerns is air monitoring and the main sources of contamination are CO(2) and other constituents of human exhaled breath. Since the inaugural meeting in 1994 in Adelaide, Australia, SAMAP meetings have been held every two or three years alternating between the North American and European continents. The meetings are organized by Dr Wally Mazurek (a member of IABR) of the Defense Systems Technology Organization (DSTO) of Australia, and individual meetings are co-hosted by the navies of the countries in which they are held. An overriding focus at SAMAP is life support (oxygen availability and carbon dioxide removal). Certainly, other air constituents are also important; for example, the closed environment of a submarine or the ISS can build up contaminants from consumer products, cooking, refrigeration, accidental fires, propulsion and atmosphere maintenance. However, the most immediate concern is sustaining human metabolism: removing exhaled CO(2) and replacing metabolized O(2). Another

  8. A tale of two orogens: Crustal processes in the Proterozoic Trans-Hudson and Grenville Orogens, eastern Canada

    Science.gov (United States)

    Darbyshire, F. A.; Bastow, I. D.; Petrescu, L.; Gilligan, A.; Thompson, D. A.

    2017-08-01

    The Precambrian core of North America was assembled in the Proterozoic by a series of collisions between Archean cratons. Among the orogenic belts, two stand out due to their significant spatial extent. The Paleoproterozoic Trans-Hudson Orogen (THO) and Mesoproterozoic Grenville Orogen extend for thousands of kilometers along strike and hundreds of kilometers across strike. Both have been compared to the present-day Himalayan-Karakoram-Tibetan Orogen (HKTO). Over the last 20-30 years, active and passive source seismic studies have contributed a wealth of information about the present-day crustal structure and composition of the two orogens in Canada. The Proterozoic orogenic crust is generally thicker than that of neighboring Archean terranes, with a more variable Moho character, ranging from relatively sharp to highly diffuse. Both orogens have a prominent high-velocity lower crustal layer, consistent with long-term preservation of a partially eclogitized root at the base of the crust and similar to that inferred beneath the western HKTO. Crustal structure in the northern THO strongly resembles the lower crustal structure of the HKTO, suggesting that Moho depths may have reached 60-70 km when the orogen was active. A prominent midcrustal discontinuity beneath the central Grenville Province and changes in the patterns of seismic anisotropy in the THO crust beneath Hudson Bay provide geophysical evidence that lower crustal flow likely played a role in the evolution of both orogens, similar to that inferred beneath the present-day HKTO. The seismic evidence from Canada supports the notion of tectonic uniformitarianism, at least as far back as the Paleoproterozoic.

  9. Submarine landslides: advances and challenges

    Science.gov (United States)

    Locat, Jacques; Lee, Homa J.

    2002-01-01

    Due to the recent development of well-integrated surveying techniques of the sea floor, significant improvements were achieved in mapping and describing the morphology and architecture of submarine mass movements. Except for the occurrence of turbidity currents, the aquatic environment (marine and fresh water) experiences the same type of mass failure as that found on land. Submarine mass movements, however, can have run-out distances in excess of 100 km, so their impact on any offshore activity needs to be integrated over a wide area. This great mobility of submarinemass movements is still not very well understood, particularly for cases like the far-reaching debris flows mapped on the Mississippi Fan and the large submarine rock avalanches found around many volcanic islands. A major challenge ahead is the integration of mass movement mechanics in an appropriate evaluation of the hazard so that proper risk assessment methodologies can be developed and implemented for various human activities offshore, including the development of natural resources and the establishment of reliable communication corridors. Key words : submarine slides, hazards, risk assessment, morphology, mobility, tsunami. Le dveloppement rcent de techniques de levs hydrograhiques pour les fonds marins nous a permis d'atteindre une qualit ingale dans la cartographie et la description des glissements sous marins. l'exception des courants de turbidit, on retrouve dans le domaine aquatique les mmes types de mouvements de terrain que sur terre. Par contre, les glissements sous-marins peuvent atteindre des distances excdant 100 km de telle sorte que leur impact sur les activits offshore doit tre pris en compte sur degrandes tendues. La grande mobilit des glissements sous-marins n'est pas encore bien comprise, comme pour le cas des coules dedbris cartographies sur le cne du Mississippi ainsi que pour les grandes avalanches rocheuses sous-marines retrouves au pourtour des les volcaniques. Un dfi majeur

  10. Focused sound from three-dimensional sound propagation effects over a submarine canyon.

    Science.gov (United States)

    Chiu, Linus Y S; Lin, Ying-Tsong; Chen, Chi-Fang; Duda, Timothy F; Calder, Brian

    2011-06-01

    Ship noise data reveal an intensification of the near-surface sound field over a submarine canyon. Numerical modeling of sound propagation is used to study the effect. The noise data were collected during an ocean acoustic and physical oceanography experiment northeast of Taiwan in 2009. In situ measurements of water sound-speed profiles and a database of high-resolution bathymetry are used in the modeling study. The model results suggest that the intensification is caused by three-dimensional sound focusing by the concave canyon seafloor. Uncertainties in the model results from unsampled aspects of the environment are discussed. © 2011 Acoustical Society of America

  11. Distribution of Gassy Sediments and Mud Volcanoes Offshore Southwestern Taiwan

    Directory of Open Access Journals (Sweden)

    Jui-Kun Chiu

    2006-01-01

    Full Text Available This study presents the results from recent intense marine geophysical surveys conducted offshore of southwestern Taiwan. Mud volcanoes and gassy sediments have been identified along chirp sonar and seismic reflection profile data. The distribution of gassy sediments and mud volcanoes has been compiled, showing these features extending from the accretionary wedge to the passive China continental margin. Submarine mud volcanoes could be grouped into four main clusters in the accretionary wedge province: offshore Kaohsiung, adjacent to the Kaoping Submarine Canyon, near the head of the Fangliao Submarine Canyon and along the Yung-An Lineament. Each cluster is composed of a few to more than 10 submarine mud volcanoes. Their origin could be related to gas hydrate dissociation with rising highpressure fluid along faults or mud diapir piercing the seafloor. These gassy sediments and mud volcanoes could be formed by fluids escaping from dewatering sedimentary layers of mud diapirs, or along faults and fractures where free gases or gases dissociating from hydrates migrate to the seafloor.

  12. Similarities between rivers and submarine channels

    Science.gov (United States)

    Balcerak, Ernie

    2013-02-01

    Scientists have long known that the width and depth of rivers follows a power law relationship with discharge. They have also noticed that submarine channels appear to be similar to terrestrial rivers, but there have not been many systematic comparisons of the relationships between submarine channel morphology and discharge. Konsoer et al. compared the width, depth, and slope of 177 submarine channels to those of 231 river cross sections. They found that submarine channels are up to an order of magnitude wider and deeper than the largest terrestrial rivers, but they exhibit a similar power law relationship between width and depth. For submarine channels that were similar in size to rivers, the authors found that submarine channels tend to be 1 to 2 orders of magnitude steeper than rivers. The authors also inferred values for sediment concentration in the turbidity currents in the channels and combined this with estimated mean flow velocities to look for a relationship between discharge and morphology in the channels. They found that like rivers, the width and depth of the submarine channels follow a power law scaling with discharge. (Journal of Geophysical Research-Earth Surface, doi:10.1029/2012JF002422, 2013)

  13. Tectonic and Paleoclimate Controls on the Denudation of Orogen Syntaxes

    Science.gov (United States)

    Ehlers, T. A.; Mutz, S.

    2016-12-01

    A range of theoretical and observational studies have investigated the interactions between climate and tectonics in active orogens. Although observed denudation histories are commonly measured over time scales ranging from decades to millions of years, rarely is information about the paleoclimate evolution of orogens available to interpret denudation histories. We use a combination of high-resolution (T159, 80x80 km) global paleoclimate models (ECHAM5), thermomechanical numerical models, and thermochronometer data to investigate the (paleo)climate and tectonic drivers for denudation in active orogens. Our emphasis is on orogen syntaxes (e.g. Himalaya, SE Alaska, Cascadia, and Central Andes) that span a range of subducting plate geometries and modern climate gradients. Results from visco-plastic thermomechanical models indicate that the pattern of localized and rapid denudation in syntaxes is initiated by the 3D geometry of subducting plates. Thermochronometer observations from the Himalaya, SE Alaska, and Cascadia syntaxes support these results. However, pronounced changes in climate accompany the Cenozoic topographic evolution of orogens. Time-slice specific paleoclimate simulations from the Mid-Holocene, Last Glacial Maximum, and Late-Pliocene indicate modest ( 10%) changes in the median of mean annual precipitation (MAP), but large ( 100-300%) changes in the maximums in MAP. Most areas investigated show an increase in the maximum in MAP since the Pliocene. A cluster analysis indicates that changes in the MAP, precipitation amplitude, and near surface temperature and amplitude, change sufficiently between the Pliocene and modern to spatially redefine the climatology of each orogen. Finally, paleoclimate simulations that investigate changes in precipitation during orogen topographic growth document significant (50-100%) localized increases in MAP during topographic development between 50-100% of the present topography.Taken together, we find: (1) the geometry of

  14. Calciclastic submarine fans: An integrated overview

    Science.gov (United States)

    Payros, Aitor; Pujalte, Victoriano

    2008-01-01

    Calciclastic submarine fans are rare in the stratigraphic record and no bona fide present-day analogue has been described to date. Possibly because of that, and although calciclastic submarine fans have long intrigued deep-water carbonate sedimentologists, they have largely been overlooked by the academic and industrial communities. To fill this gap we have compiled and critically reviewed the existing sedimentological literature on calciclastic submarine fans, thus offering an updated view of this type of carbonate slope sedimentary system. Calciclastic submarine fans range in length from just a few to more than 100 km. Three different types can be distinguished: (1) Coarse-grained, small-sized (depression associated with tectonic structures, an inherited topography, or large-scale mass failures.

  15. Aspects of Propeller Developements for a Submarine

    DEFF Research Database (Denmark)

    Andersen, Poul; kappel, Jens Julius; Spangenberg, Eugen

    2009-01-01

    Design and development of propellers for submarines are in some ways different from propellers for surface vessels. The most important demand is low acoustic signature that has priority over propeller efficiency, and the submarine propeller must be optimized with respect to acoustics rather than...... efficiency. Moreover the operating conditions of a submarine propeller are quite different. These aspects are discussed as well as the weighing of the various propeller parameters against the design objectives. The noise generated by the propeller can be characterized as thrust noise due to the inhomogeneous...... wake field of the submarine, trailing-edge noise and noise caused by turbulence in the inflow. The items discussed are demonstrated in a case study where a propeller of the Kappel type was developed. Three stages of the development are presented, including a design of an 8-bladed propeller where...

  16. Russia's Submarine Force: Determinants and Prospects

    National Research Council Canada - National Science Library

    Tully, John

    2001-01-01

    ... the determinants of these events, The Russian Federation inherited a huge submarine fleet from the Soviet Union, Due to the changing conditions in the world and in Russia, its future status is in doubt...

  17. Collaborative Taiwan-USA Seismic Onshore-Offshore Imaging of Arc-Continent Collision under Taiwan

    Science.gov (United States)

    Okaya, D. A.; Wang, C.; Kuo, Y. N.; Yen, H.; Huang, B.; Liang, W.; Shih, M.; Wen, S.; Wu, F. T.

    2009-12-01

    deployment. The combination of airgun shiptracks and land stations present a possible 19,600 station receiver gathers. Data extraction was carried out at the Taiwan Earthquake Center data center; archived airgun and earthquake gathers represent 2.9 Tbytes of data. Quality of onshore-offshore data vary with ship distance from island coastline, land station siting of urban and mountain environments, day versus night recording, and seafloor geology enabling source transmission. Pg, PmP, PiP, and Sg phases are cleary visible. We present these phases in airgun and earthquake data plots and preliminary interpretations of Taiwan velocity structure. These data will address scientific questions including: Does continental subduction play an important role in arc-continent collision? Is the mass of incoming continental crust balanced by crustal thickening and erosion? How does such an orogen evolve over time?

  18. SSN 774 Virginia Class Submarine (SSN 774)

    Science.gov (United States)

    2015-12-01

    Report: The VIRGINIA Class Submarine Program continues to deliver submarines within cost, ahead of schedule , with improved quality and with...baseline schedule threshold set ten years earlier, in 1994. June 20, 2006: USS TEXAS, which was essentially the second lead ship of the class , is the first...factored for the VIRGINIA Class based on weight. Public and private shipyard data was used, as well as the maintenance schedule provided in the CARD, Rev E

  19. Submarine landslides: processes, triggers and hazard prediction.

    Science.gov (United States)

    Masson, D G; Harbitz, C B; Wynn, R B; Pedersen, G; Løvholt, F

    2006-08-15

    Huge landslides, mobilizing hundreds to thousands of km(3) of sediment and rock are ubiquitous in submarine settings ranging from the steepest volcanic island slopes to the gentlest muddy slopes of submarine deltas. Here, we summarize current knowledge of such landslides and the problems of assessing their hazard potential. The major hazards related to submarine landslides include destruction of seabed infrastructure, collapse of coastal areas into the sea and landslide-generated tsunamis. Most submarine slopes are inherently stable. Elevated pore pressures (leading to decreased frictional resistance to sliding) and specific weak layers within stratified sequences appear to be the key factors influencing landslide occurrence. Elevated pore pressures can result from normal depositional processes or from transient processes such as earthquake shaking; historical evidence suggests that the majority of large submarine landslides are triggered by earthquakes. Because of their tsunamigenic potential, ocean-island flank collapses and rockslides in fjords have been identified as the most dangerous of all landslide related hazards. Published models of ocean-island landslides mainly examine 'worst-case scenarios' that have a low probability of occurrence. Areas prone to submarine landsliding are relatively easy to identify, but we are still some way from being able to forecast individual events with precision. Monitoring of critical areas where landslides might be imminent and modelling landslide consequences so that appropriate mitigation strategies can be developed would appear to be areas where advances on current practice are possible.

  20. Reconciling regional continuity with local variability in structure, uplift and exhumation of the Timor orogen

    NARCIS (Netherlands)

    Tate, Garrett W.; McQuarrie, Nadine; Tiranda, Herwin; van Hinsbergen, D.J.J.; Harris, Ron; Zachariasse, Willem Jan; Fellin, Maria Giuditta; Reiners, Peter W.; Willett, Sean D.

    Along-strike variations in orogenic development can be difficult to constrain. Resulting assumptions projecting similarity or variability along strike can lead to erroneous conclusions at the orogen scale. Young orogens provide opportunities to document limits of along-strike projection and test

  1. Post-orogenic evolution of mountain ranges and associated foreland basins: Initial investigation of the central Pyrenees

    Science.gov (United States)

    Bernard, Thomas; Sinclair, Hugh; Ford, Mary; Naylor, Mark

    2017-04-01

    Mountain topography, including surrounding foreland basins, results from the long-term competition between tectonic and surface processes linked to climate. Numerous studies on young active mountain ranges such as the Southern Alps, New Zealand and Taiwan, have investigated the interaction between tectonics, climate and erosion on the topographic landscape. However most of the mountain ranges in the world are in various stages of post-orogenic decay, such as the European Alps, Urals, Caledonides, Appalachians and Pyrenees. The landscape evolution of these decaying mountains, which involve relatively inactive tectonics, should appear simple with progressive and relatively uniform erosion resulting in a general lowering of both elevation and topographic relief. However, in a number of examples, post-orogenic systems suggest a complex dynamism and interactions with their associated foreland basins in term of spatio-temporal variations in erosion and sedimentary flux. The complexity and transition to post-orogenesis is a function of multiple processes. Underpinning the transition to a post-orogenic state is the competition between erosion and crustal thickening; the balance of these processes determines the timing and magnitude of isostatic rebound and hence subsidence versus uplift of the foreland basin. It is expected that any change in the parameters controlling the balance of erosion versus crustal thickening will impact the topographic evolution and sediment flux from the mountain range and foreland basin to the surrounding continental margin. This study will focus on the causes and origins of the processes that define post-orogenesis. This will involve analyses of low-temperature thermochronological and topographic data, geodynamical modelling and sedimentological analyses (grainsize distribution). The Pyrenees and its associated northern retro-foreland basin, the Aquitaine basin, will form the natural laboratory for the project as it is one of the best

  2. Paleotsunamis in Taiwan

    Science.gov (United States)

    Yen, J. Y.; Yu, N. T.; Chyi, S. J.; Lin, L. H.; Hirakawa, K.; Sugawara, D.

    2015-12-01

    Sitting between the Ryukyu and Manila subduction systems, Taiwan is among the world's most tectonically and seismically active areas. However, unlike Japan (from Hokkaido to the southernmost tip of Ryukyu), Taiwan is not known for tsunami events. Historical documents and folklores in Taiwan show a couple of records with different degree of certainty of tsunami, yet very few researches were conducted in paleotsunami researches. During the past two years, we have conducted detail field surveys in Taiwan, and in several chosen area we have conducted shallow bore holes, trench excavations, and following geological and geomorphological researches. Our data show that northern Taiwan has been affected by tsunami both on and off historical records, and could be as many as 8 events. In eastern Taiwan, there are three probable tsunami events, and in western Taiwan, three or four inudation events were discovered that have features very similar to tsunamis. In addtion to continuing field survey, we are performing numerical modeling based on the newly discovered geological evidences. The purpose is the reconstruct the processes of events and find the possilbe sources.

  3. Geomorphic process fingerprints in submarine canyons

    Science.gov (United States)

    Brothers, Daniel S.; ten Brink, Uri S.; Andrews, Brian D.; Chaytor, Jason D.; Twichell, David C.

    2013-01-01

    Submarine canyons are common features of continental margins worldwide. They are conduits that funnel vast quantities of sediment from the continents to the deep sea. Though it is known that submarine canyons form primarily from erosion induced by submarine sediment flows, we currently lack quantitative, empirically based expressions that describe the morphology of submarine canyon networks. Multibeam bathymetry data along the entire passive US Atlantic margin (USAM) and along the active central California margin near Monterey Bay provide an opportunity to examine the fine-scale morphology of 171 slope-sourced canyons. Log–log regression analyses of canyon thalweg gradient (S) versus up-canyon catchment area (A) are used to examine linkages between morphological domains and the generation and evolution of submarine sediment flows. For example, canyon reaches of the upper continental slope are characterized by steep, linear and/or convex longitudinal profiles, whereas reaches farther down canyon have distinctly concave longitudinal profiles. The transition between these geomorphic domains is inferred to represent the downslope transformation of debris flows into erosive, canyon-flushing turbidity flows. Over geologic timescales this process appears to leave behind a predictable geomorphic fingerprint that is dependent on the catchment area of the canyon head. Catchment area, in turn, may be a proxy for the volume of sediment released during geomorphically significant failures along the upper continental slope. Focused studies of slope-sourced submarine canyons may provide new insights into the relationships between fine-scale canyon morphology and down-canyon changes in sediment flow dynamics.

  4. Educational Technology in Taiwan.

    Science.gov (United States)

    Tu, Chih-Hsiung; Twu, Hui-Ling

    2002-01-01

    Examines educational technology applications in Taiwan. Highlights include historical background; learning technology integration; computer availability; teacher training; student and teacher attitudes; computer-mediated communication and collaboration; curriculum planning; distance education; and an educational technology model that includes…

  5. Addressing submarine geohazards through scientific drilling

    Science.gov (United States)

    Camerlenghi, A.

    2009-04-01

    Natural submarine geohazards (earthquakes, volcanic eruptions, landslides, volcanic island flank collapses) are geological phenomena originating at or below the seafloor leading to a situation of risk for off-shore and on-shore structures and the coastal population. Addressing submarine geohazards means understanding their spatial and temporal variability, the pre-conditioning factors, their triggers, and the physical processes that control their evolution. Such scientific endeavour is nowadays considered by a large sector of the international scientific community as an obligation in order to contribute to the mitigation of the potentially destructive societal effects of submarine geohazards. The study of submarine geohazards requires a multi-disciplinary scientific approach: geohazards must be studied through their geological record; active processes must be monitored; geohazard evolution must be modelled. Ultimately, the information must be used for the assessment of vulnerability, risk analysis, and development of mitigation strategies. In contrast with the terrestrial environment, the oceanic environment is rather hostile to widespread and fast application of high-resolution remote sensing techniques, accessibility for visual inspection, sampling and installation of monitoring stations. Scientific Drilling through the IODP (including the related pre site-survey investigations, sampling, logging and in situ measurements capability, and as a platform for deployment of long term observatories at the surface and down-hole) can be viewed as the centre of gravity of an international, coordinated, multi-disciplinary scientific approach to address submarine geohazards. The IODP Initial Science Plan expiring in 2013 does not address openly geohazards among the program scientific objectives. Hazards are referred to mainly in relation to earthquakes and initiatives towards the understanding of seismogenesis. Notably, the only drilling initiative presently under way is the

  6. MVAC Submarine cable, impedance measurements and analysis

    DEFF Research Database (Denmark)

    Arentsen, Martin Trolle; Pedersen, Morten Virklund; Expethit, Adrian

    2017-01-01

    Due to environmental concerns an increase in off-shore windfarms has been observed in recent years, leading to an increased demand for three-core-wire-armoured submarine cables. However, the IEC Standard 60287 used to calculate the ampacity of these cables is widely recognized as being not accurate...

  7. German Submarine Offensives and South African Countermeasures

    African Journals Online (AJOL)

    Evert

    'Good Hunting': German Submarine Offensives and South African. Countermeasures off the South African Coast during the Second World. War, 1942-1945. Evert Kleynhans. •. Abstract .... wolf packs south, Dönitz had hoped to cause a diversionary effect whereby the Allies would be forced to split their defensive forces ...

  8. Submarine Telecommunication Cables in Disputed Maritime Areas

    NARCIS (Netherlands)

    van Logchem, Youri

    2014-01-01

    There are a considerable number of maritime areas where no boundary exists, or where a boundary is delimited only in part. This article deals with the issue of submarine telecommunication cables, which are sometimes placed on the seabed or buried in the subsoil of areas that are claimed by multiple

  9. Monitoring of the nuclear submarine Komsomolets

    Energy Technology Data Exchange (ETDEWEB)

    Heldal, Hilde E.; Flo, Janita K.; Liebig, Penny L. [Institute of Marine Research, P. O. Box 1870 Nordnes, N-5817 Bergen (Norway); Gaefvert, Torbjoern; Rudjord, Anne Liv [Norwegian Radiation Protection Authority, P.O. Box 55, N-1332 Oesteraas (Norway); Gwynn, Justin P. [Norwegian Radiation Protection Authority, The Fram Centre, N-9296 Tromsoe (Norway)

    2014-07-01

    The Soviet nuclear submarine Komsomolets sank on the 7 April 1989, 180 km southwest of Bear Island in the Norwegian Sea to a depth of about 1655 m. The submarine contains one nuclear reactor containing long-lived radionuclides such as cesium-137 ({sup 137}Cs) along with other fission and activation products, in addition to 2 mixed uranium/plutonium nuclear warheads containing weapons grade plutonium. Although several model studies have shown that a radioactive leakage from Komsomolets will have insignificant impact on fish and other marine organisms, there are still public concerns about the condition of the submarine and the potential for radioactive leakage. In order to document the contamination levels and to meet public concerns, monitoring of radioactive contamination in the area adjacent to the submarine has been ongoing since 1993. Samples of bottom seawater and sediments have been collected annually by the Institute of Marine Research (IMR) and have been analysed for {sup 137}Cs and plutonium-239,240 ({sup 239,240}Pu). So far, activity concentrations in the samples have been comparable to levels found in other samples from the Norwegian and Barents Seas. During sampling from R/V 'G. O. Sars' in April 2013, an area of about 1 km{sup 2} of the seabed around Komsomolets was mapped to precisely locate the submarine using a Kongsberg EM302 multibeam echo sounder, a Simrad EK60 single beam echo sounder and an Olex 3D bottom-mapping system. For sediment sampling, a Simrad MST342 mini-transponder was attached to a Smoegen box corer to allow for precise positioning of the corer. With the aid of the Kongsberg HiPAP (High Precision Acoustic Positioning) system, 4 box cores were collected around the submarine at a distance of 10 to 20 m. In addition, one box core was collected from a reference station about 100 m upstream of the submarine. Surface sediments and sediment cores were collected from the box cores taken at each sampling location. Sediment cores

  10. Chemical environments of submarine hydrothermal systems

    Science.gov (United States)

    Shock, Everett L.

    1992-01-01

    Perhaps because black-smoker chimneys make tremendous subjects for magazine covers, the proposal that submarine hydrothermal systems were involved in the origin of life has caused many investigators to focus on the eye-catching hydrothermal vents. In much the same way that tourists rush to watch the spectacular eruptions of Old Faithful geyser with little regard for the hydrology of the Yellowstone basin, attention is focused on the spectacular, high-temperature hydrothermal vents to the near exclusion of the enormous underlying hydrothermal systems. Nevertheless, the magnitude and complexity of geologic structures, heat flow, and hydrologic parameters which characterize the geyser basins at Yellowstone also characterize submarine hydrothermal systems. However, in the submarine systems the scale can be considerably more vast. Like Old Faithful, submarine hydrothermal vents have a spectacular quality, but they are only one fascinating aspect of enormous geologic systems operating at seafloor spreading centers throughout all of the ocean basins. A critical study of the possible role of hydrothermal processes in the origin of life should include the full spectrum of probable environments. The goals of this chapter are to synthesize diverse information about the inorganic geochemistry of submarine hydrothermal systems, assemble a description of the fundamental physical and chemical attributes of these systems, and consider the implications of high-temperature, fluid-driven processes for organic synthesis. Information about submarine hydrothermal systems comes from many directions. Measurements made directly on venting fluids provide useful, but remarkably limited, clues about processes operating at depth. The oceanic crust has been drilled to approximately 2.0 km depth providing many other pieces of information, but drilling technology has not allowed the bore holes and core samples to reach the maximum depths to which aqueous fluids circulate in oceanic crust. Such

  11. Phase 1 Final Report: Titan Submarine

    Science.gov (United States)

    Oleson, Steven R.; Lorenz, Ralph D.; Paul, Michael V.

    2015-01-01

    The conceptual design of a submarine for Saturn's moon Titan was a funded NASA Innovative Advanced Concepts (NIAC) Phase 1 for 2014. The proposal stated the desire to investigate what science a submarine for Titan's liquid hydrocarbon seas might accomplish and what that submarine might look like. Focusing on a flagship class science system (100 kg), it was found that a submersible platform can accomplish extensive science both above and below the surface of the Kraken Mare. Submerged science includes mapping using side-looking sonar, imaging and spectroscopy of the lake, as well as sampling of the lake's bottom and shallow shoreline. While surfaced, the submarine will not only sense weather conditions (including the interaction between the liquid and atmosphere) but also image the shoreline, as much as 2 km inland. This imaging requirement pushed the landing date to Titan's next summer period (2047) to allow for lighted conditions, as well as direct-to-Earth communication, avoiding the need for a separate relay orbiter spacecraft. Submerged and surfaced investigation are key to understanding both the hydrological cycle of Titan as well as gather hints to how life may have begun on Earth using liquid, sediment, and chemical interactions. An estimated 25 Mb of data per day would be generated by the various science packages. Most of the science packages (electronics at least) can be safely kept inside the submarine pressure vessel and warmed by the isotope power system.The baseline 90-day mission would be to sail submerged and surfaced around and through Kraken Mare investigating the shoreline and inlets to evaluate the sedimentary interaction both on the surface and then below. Depths of Kraken have yet to be sensed (Ligeia to the north is thought to be 200 m (656 ft) deep), but a maximum depth of 1,000 m (3,281 ft) for Kraken Mare was assumed for the design). The sub would spend 20 d at the interface between Kraken Mare and Ligeia Mare for clues to the drainage of

  12. The mechanism of forearc basement subduction in eastern Taiwan: Insights from sandbox modeling: Insight from Sandbox

    Science.gov (United States)

    Lu, Chia-Yu

    2015-04-01

    In Taiwan today, the subduction of the Chinese continental margin under the Philippine Sea plate results in the progressive growth of an active orogenic wedge. It is one of the best places to study the complex relationships that occur between the tectono-metamorphic processes controlling deformation (plate rheology and kinematics) and surface processes (erosion and sedimentation). In the Central Range of Taiwan, foliation and lineation traces outline the geometry and kinematics of deformation in both, the foreland and hinterland of the orogenic wedge. The foliation dip and the strain ellipsoids distribution show the fan shape of a large pop-up structure characterizing the effects of oblique plate convergence. On the eastern flank, regionally developed penetrative cleavage dips, isotope data and sedimentary structures demonstrating regional overturned structures. Two mélange units, the Kenting and Lichi mélange are exposed at the south and east of the Central Range respectively. Experiments allow the study of interactions between tectonics and surface processes. Accounting for various boundary conditions and parameters such as sedimentation, erosion, basal friction, and décollement level. We present the results of 2D and 3D sandbox models designed to investigate the complex deformation characterizing the active Taiwan orogenic wedge and to demonstrate the development of those mélanges, overturned structures and mountain frontal thrusts. Models are analyzed using pictures, movies and PIV (Particle Image Velocimetry software). We then characterize the exhumation patterns, the mode of fault propagation and displacement patterns by strain partitioning of those mélanges and overturned structures.

  13. The eastern Central Asian Orogenic Belt: formation and evolution

    Science.gov (United States)

    Xu, Bei; Xu, Wenliang

    2017-08-01

    The Central Asian Orogenic Belt (CAOB) extends from the northern Eurasian continent in the west via Mongolia, Inner Mongolia and northeast part of China to the Russia Far East in the east. It is characterized by complex trench-arc-basin subduction system, exotic terrane (microcontinents) accretion, massive generation of juvenile crust during the Neoproterozoic-Phanerozoic (e.g., Jahn et al., 2000, 2004; Sengör et al., 1993). A lot of papers about formation and evolution of the CAOB have been published and new field observations and geochemical data for key areas of the CAOB challenge to previous assessments. Several areas previously defined as juvenile are now shown to have mixed crustal compositions. For example, Kröner et al. (2014, in press) estimated that the distribution of various crustal provinces is truly juvenile crustal material ca. 20%, mixed crust ca. 30%, old crust ca. 50%,respectively, in the CAOB, similar to those in other accretionary orogens through Earth history. A two-stage model for the evolution of the CAOB has been suggested based on recent data from the Eastern Tianshan and Beishan (Gao et al., 2011; Su et al., 2011; Chen et al., 2016; Wang et al., 2017), which suggests the process of the formation and evolution of the CAOB includes closure of the Paleo Asian ocean (PAO), formation of orogenic belt before the late Paleozoic and crustal extension and magmatism resulted from plume upon the young orogenic belt after the late Paleozoic. This new model changes previous concept that the CAOB developed through the Paleozoic and is supported by recent researches on the eastern CAOB.

  14. Topographic evolution of orogens: The long term perspective

    Science.gov (United States)

    Robl, Jörg; Hergarten, Stefan; Prasicek, Günther

    2017-04-01

    The landscape of mountain ranges reflects the competition of tectonics and climate, that build up and destroy topography, respectively. While there is a broad consensus on the acting processes, there is a vital debate whether the topography of individual orogens reflects stages of growth, steady-state or decay. This debate is fuelled by the million-year time scales hampering direct observations on landscape evolution in mountain ranges, the superposition of various process patterns and the complex interactions among different processes. In this presentation we focus on orogen-scale landscape evolution based on time-dependent numerical models and explore model time series to constrain the development of mountain range topography during an orogenic cycle. The erosional long term response of rivers and hillslopes to uplift can be mathematically formalised by the stream power and mass diffusion equations, respectively, which enables us to describe the time-dependent evolution of topography in orogens. Based on a simple one-dimensional model consisting of two rivers separated by a watershed we explain the influence of uplift rate and rock erodibility on steady-state channel profiles and show the time-dependent development of the channel - drainage divide system. The effect of dynamic drainage network reorganization adds additional complexity and its effect on topography is explored on the basis of two-dimensional models. Further complexity is introduced by coupling a mechanical model (thin viscous sheet approach) describing continental collision, crustal thickening and topography formation with a stream power-based landscape evolution model. Model time series show the impact of crustal deformation on drainage networks and consequently on the evolution of mountain range topography (Robl et al., in review). All model outcomes, from simple one-dimensional to coupled two dimensional models are presented as movies featuring a high spatial and temporal resolution. Robl, J., S

  15. The arcuate fold-and-thrust belt of northern Taiwan: Results of a two-stage rotation revealed from a paleomagnetic study

    Science.gov (United States)

    Sonnette, Lionel; Lee, Jian-Cheng; Horng, Chorng-Shern

    2017-10-01

    The Taiwan orogen is the result of the collision of the Luzon Volcanic Arc pushed northwestward by the Philippine Sea Plate against the Chinese Continental Margin since the Late Miocene and is still uplifting nowadays. The fold-and-thrust belt in northern Taiwan shows an arcuate shape from SW to NE: the strike of the main tectonic structures changes from N 0 ° E to N 70 ° E. Such curvature has not yet been properly interpreted so far. In this study we used paleomagnetic analyses to decipher the tectonic evolution along the fold-and-thrust belt in northern Taiwan, which reveals complex magnetization patterns both in ante-folding and post-folding formations. We also interpret that the fold-and-thrust belt in northern Taiwan has experienced two main rotational events: a 30 - 60 ± 14 ° clockwise rotation followed by a 30 ± 7 ° counterclockwise rotation during the ages of 4.6-1.5 Ma.

  16. Orogenic mass changes detectable in satellite gravity missions

    Science.gov (United States)

    Braitenberg, Carla; Pivetta, Tommaso; Morsut, Federico

    2017-04-01

    Long term GNSS time series detect vertical crustal movement rates, which typically at orogens demonstrate uplift. The orogenic uplift can be ascribed to tectonic and post-glacial adjustments and crustal thickening. We investigate the sensitivity of satellite gravity change rate observations to detect the associated mass changes. Gravity change rate joint with uplift monitoring allows to distinguish the mechanism of uplift (Braitenberg and Shum, 2016). We use known vertical uplift rates over specific orogens to predict the gravity change for different geodynamic hypotheses of pure uplift and mantle inflow, or crustal thickening and isostatic Moho lowering. The sensitivity of gravity as a tool to distinguish the two mechanisms is investigated. The estimate of this tectonic signal is important, when the observed gravity change rates of GRACE and future missions are interpreted exclusively in terms of hydrologic changes tied to climatic variation. We find that in some areas, as the Tibetan plateau and the Himalayan- Alpine range, the tectonic signal is measurable by satellite gravity and contributes to a better understanding of the geodynamic processes leading to orogenesis. Braitenberg C. and Shum C. K. (2016). Geodynamic implications of temporal gravity changes over Tibetan Plateau. Italian Journal of Geosciences, in press.

  17. “Hello, HELLO! Anyone there? - on the need to assess the tsunami risk to global submarine telecommunications infrastructure

    Science.gov (United States)

    Dominey-Howes, D.; Goff, J. R.

    2009-12-01

    National economies are increasingly dependent on the global telecommunications system - and in particular, its submarine cable infrastructure. Submarine cable traffic represents about 30% of global GDP so the cost of losing, or even simply slowing, communications traffic is high. Many natural hazards are capable of damaging and destroying this infrastructure but tsunamis are the most significant threat, particularly in waters >1000 m deep. Submarine cables and their shore-based infrastructure (the anchor points), are at risk from direct and indirect tsunami-related effects. During the 2004 Indian Ocean Tsunami in India and Indonesia, cables were broken (direct effect) as the tsunami eroded supporting sediments, and were further damaged by floating/submerged objects and intense nearshore currents. Shore-based infrastructure was also directly damaged in India, Indonesia, and the Maldives. The 1929 Grand Banks earthquake generated a submarine landslide and tsunami off Newfoundland which broke 12 submarine telegraph cables. In 2006, an earthquake in Taiwan generated submarine landslides and a tsunami. These landslides caused one of the largest disruptions of modern telecommunications history when nine cables in the Strait of Luzon were broken disabling vital connections between SE Asia and the rest of the world. Although electronic traffic in and out of Australia was slowed, it did not cease because >70% of our traffic is routed via cables that pass through Hawaii. This is extremely significant because Hawaii is an internationally recognised bottleneck or “choke point” in the global telecommunications network. The fact that Hawaii is a choke point is important because it is regularly affected by numerous large magnitude natural hazards. Any damage to the submarine telecommunications infrastructure routed through Hawaii could result in significant impacts on the electronic flow of data and voice traffic, negatively affecting dependent economies such as Australia

  18. Moment-tensor inversion for offshore earthquakes east of Taiwan and their implications to regional collision

    Science.gov (United States)

    Kao, Honn; Jian, Pei-Ru; Ma, Kuo-Fong; Huang, Bor-Shouh; Liu, Chun-Chi

    Reliable determination of source parameters for offshore earthquakes east of Taiwan with mbcope with different patterns of background noise and unknown structural details, we utilize variable frequency bands in the inversion and adapt a two-step procedure to select best velocity models for individual epicenter-station paths. Our results are consistent with the overall patterns of regional collision and indicate that the resulting compressive stress has caused significant intraplate deformation within the Philippine Sea plate. Simulation of the region's geological evolution and orogenic processes should take this factor into account and allow the Philippine Sea plate to deform internally.

  19. Luminescence characteristics of quartz from Hsuehshan Range (Central Taiwan) and implications for thermochronometry

    DEFF Research Database (Denmark)

    Wu, Tzu-Shuan; Jain, Mayank; Guralnik, Benny

    2015-01-01

    The mountain building processes in Taiwan are currently among the most rapid in the world. However, the spatial and temporal dynamics of this orogen are still poorly resolved within the <0.5 Ma timescale, reflecting methodological gaps in addressing young and rapid bedrock cooling by erosion. Opt...... that these samples may be valuable for evaluating recent cooling rates exceeding 360 ± 100 C/Ma, in places where the alternative thermal scenarios (instantaneous cooling or prolonged isothermal storage) may be ruled out by external geological constraints....

  20. Sun glitter imaging analysis of submarine sand waves in HJ-1A/B satellite CCD images

    Science.gov (United States)

    Zhang, Huaguo; He, Xiekai; Yang, Kang; Fu, Bin; Guan, Weibing

    2014-11-01

    Submarine sand waves are a widespread bed-form in tidal environment. Submarine sand waves induce current convergence and divergence that affect sea surface roughness thus become visible in sun glitter images. These sun glitter images have been employed for mapping sand wave topography. However, there are lots of effect factors in sun glitter imaging of the submarine sand waves, such as the imaging geometry and dynamic environment condition. In this paper, several sun glitter images from HJ-1A/B in the Taiwan Banks are selected. These satellite sun glitter images are used to discuss sun glitter imaging characteristics in different sensor parameters and dynamic environment condition. To interpret the imaging characteristics, calculating the sun glitter radiance and analyzing its spatial characteristics of the sand wave in different images is the best way. In this study, a simulated model based on sun glitter radiation transmission is adopted to certify the imaging analysis in further. Some results are drawn based on the study. Firstly, the sun glitter radiation is mainly determined by sensor view angle. Second, the current is another key factor for the sun glitter. The opposite current direction will cause exchanging of bright stripes and dark stripes. Third, brightness reversal would happen at the critical angle. Therefore, when using sun glitter image to obtain depth inversion, one is advised to take advantage of image properties of sand waves and to pay attention to key dynamic environment condition and brightness reversal.

  1. Psychological Implications for Submarine Display Design

    Science.gov (United States)

    2005-08-01

    This paper addresses a number of psychological issues pertaining to display design . We review the literature comparing 3-D and 2-D displays and...perceptual, cognitive and ecological factors that are relevant to display design for submarine environments. The Generative Transformational approach...to visual perception is outlined and the relevance of transformational theory to display design is discussed. The paper also discusses a number of

  2. Topology Model of the Flow around a Submarine Hull Form

    Science.gov (United States)

    2015-12-01

    resistance and flow noise arising from flow-structure interaction, it is necessary to test the shape of the submarine , which includes the length-to...UNCLASSIFIED Topology Model of the Flow around a Submarine Hull Form S.-K. Lee Maritime Division Defence Science and Technology Group DST-Group–TR...3177 ABSTRACT A topology model constructed from surface-streamer visualisation describes the flow around a generic conventional submarine hull form at

  3. A Lanchester model of submarine attack on a carrier battlegroup

    OpenAIRE

    Eagle, James N.

    1987-01-01

    A Lanchester model is developed for a battlegroup ASW engagement. Two variations are included. In the first, long-range missile firing submarines, short-range missile or torpedo firing submarines, and submarines firing only torpedoes distribute their attack uniformly over battlegroup escort ships and carriers. In the second variation, the attack is concentrated on the carriers. supported by the Naval War College http://archive.org/details/lanchestermodelo00eagl NA

  4. Distribution and Characters of Gas Hydrate Offshore of Southwestern Taiwan

    Directory of Open Access Journals (Sweden)

    Char-Shine Liu

    2006-01-01

    Full Text Available Bottom simulating reflector (BSR is a key indicator for the presence of gas hydrate beneath the sea floor. Widely distributed BSRs have been observed in the area offshore of southwestern Taiwan where the active accretionary complex meets with the passive China continental margin. In order to better understand the distribution and characters of the gas hydrate in the region, closely spaced (1.86-km line spacing multichannel seismic reflection surveys have been conducted in recent years under the support of the Central Geological Survey, ROC. Over 10000 km of multichannel seismic reflection profiles have been collected that cover an area of about 10000 km2 offshore of southwestern Taiwan. BSRs can be identified along 50% of the seismic profiles that we collected. A newly compiled BSR distribution map suggests that gas hydrates are distributed both in the passive margin of the China continental slope as well as in the submarine Taiwan accretionary wedge, from water depths of 500 to over 3000 m. Gas hydrates are most concentrated underneath anticlinal ridges in the accretionary wedge, and underneath the slope ridges of the passive continental margin that were formed due to sedimentary processes. Active fluid activities are evident from various features observed on seismic reflection and chirp sonar profiles, such as mud volcanoes, gas plumes and gas charged shallow sedimentary layers. Fluid migration model has been established from a set of pseudo 3D seismic reflection data. The predicted locations of high fluid flux correlate well with those interpreted from geochemical analyses that show very high methane concentrations and very shallow sulfate-methane interfaces (SMI. This demonstrates the importance of structural control over gas hydrate emplacement. From the observed gas hydrate distribution and characters, the area offshore of southwestern Taiwan provides an ideal place to study and compare the formation and migration of gas hydrates under

  5. Predictive mapping of prospectivity for orogenic gold in Uganda

    Science.gov (United States)

    Herbert, Sarah; Woldai, Tsehaie; Carranza, Emmanuel John M.; van Ruitenbeek, Frank J. A.

    2014-11-01

    Integration of enhanced regional geo-datasets has facilitated new geological interpretation and modelling of prospectivity for orogenic gold in southwestern Uganda. The geo-datasets include historical geological maps, geological field data, digital terrain models, Landsat TM data and airborne geophysical data. The study area, bordered by the western branch of the East African Rift, covers a range of different aged terranes including the Archaean basement gneisses, Palaeoproterozoic volcano-sedimentary Buganda Toro Belt, Mesoproterozoic clastic sedimentary Karagwe Ankolean Belt and several outliers of undeformed Neoproterozoic sediments. The mineral systems approach to practical exploration targeting requires a framework to link conceptual models of mineralisation with available data. A conceptual model requires good understanding of key processes and their timing within the geodynamic history of an area. The challenge is that processes cannot be mapped, only their results or effects. In this study, a district-scale (1:100,000) investigation is considered appropriate given the scarcity of geological information and the absence of world-renowned gold deposits in southwestern Uganda. At this scale of orogenic gold mineral systems understanding, evidence for the source of gold, active pathways and the physical traps are considered critical. Following the mineral system approach, these processes critical to orogenic gold systems are translated into district-scale mappable proxies using available regional-scale datasets. Tectono-stratigraphic domains, mantle indicators and gold occurrences represent the “source of gold” as a critical process. Zones of hydrothermal alteration were extracted from radiometric data, structures involved in the orogenies and terrane contacts were extracted to represent the active pathway as a critical process and finally the physical throttle is represented by rheological contrasts and geological complexity. Then, the knowledge

  6. Convergence rate controls seismicity styles in collision orogens

    Science.gov (United States)

    Dal Zilio, Luca; van Dinther, Ylona; Gerya, Taras

    2016-04-01

    The 25 April 2015 Mw 7.8 Gorkha earthquake in Nepal resulted from the unzipping of the previously locked Main Himalayan Thrust (MHT) fault, along which the Himalayan wedge is thrust over India. Strong ground shaking caused the collapse of more than half a million homes, killing more than 8500 people. Can such a large magnitude event also occur within the populated European Alps? Or is there a distinctly different seismicity pattern in different orogens? We show that their long-term seismicity patterns are indeed different and that their differences can be explained by a single parameter: their convergence rate. To do so we present the first self-consistent seismic cycle model for continental collisional margins. We use the viscoelastoplastic continuum Seismo-Thermo-Mechanical model (STM) validated for seismic cycle applications against a laboratory model (van Dinther et al., 2013a) and natural observations (van Dinther et al., 2013b), which includes Drucker-Prager plasticity and spontaneous rupture events governed by strongly rate-dependent friction. The 2-D model setup consists of two continental plates separated by an oceanic plate, in which the incipient subduction phase is followed by collisional orogeny. Results show the physically consistent spontaneous emergence of complex rupture paths, both on and off the main frontal thrust. These off-main frontal thrust events within the upper and lower plate complement the main frontal thrust seismicity leading to a Gutenberg-Richter frequency-magnitude distribution. This is a key observational feature of seismicity, which is typically not reproduced in seismic cycle models. The range of simulated b-values agrees with natural ranges, as we observe values from 0.97 up to 1.25 for convergence rates decreasing from 5 to 1 cm/yr. Decreasing convergence rates thus lead to relatively larger amounts of smaller earthquakes (increasing b-value) and lower maximum magnitudes. This change in b-value also observed to corresponds to

  7. Meta-Analysis of Data from the Submarine Ventilation Doctrine Test Program

    National Research Council Canada - National Science Library

    Hoover, J

    1998-01-01

    .... The Submarine Ventilation Doctrine Test Program was developed to address submarine-specific issues regarding the use of ventilation systems to control smoke and heat movement, maintain habitability...

  8. Late-orogenic extension and strike-slip deformation in the Neogene of southeastern Spain

    NARCIS (Netherlands)

    Meijninger, B.M.L.

    2006-01-01

    The Betic Cordillera of southern Spain form the western end of the Alpine orogen, which during the Neogene was affected by large-scale late-orogenic extension. Extension, however, occurred within a setting of continuous slow convergence of the African and European plates. During the Neogene,

  9. The Preliminary Study of the 4 March 2010 Mw 6.3 Jiasian, Taiwan Earthquake Sequence

    Directory of Open Access Journals (Sweden)

    Hsin-Hua Huang

    2011-01-01

    Full Text Available On 4 March 2010, an inland Mw 6.3 earthquake occurred near the town of Jiasian in Kaohsiung County, Taiwan causing large ground shaking and extensive damage. In this study, we integrate the records from the Central Weather Bureau Seismic Network (CWBSN and Taiwan Strong Motion Instrumentation Program (TSMIP to obtain the relocated earthquake sequence and its first-motion focal mechanisms. This dataset offers us precise and reliable results which suggest a focal depth of 23 km and a possible fault plane of strike 313¢X, dip 41¢X, and rake 42¢X for the Jiasian earthquake. This fault plane significantly differs from the N-S striking Chaochou Fault (CCF as well as the principal trend of Taiwan orogenic belt, and should be an undiscovered fault in southern Taiwan. The relocated Jiasian earthquake sequence initiating from the 23-km-deep mainshock and terminating at around 10 km in depth also indicates it is a blind fault. Peak ground acceleration (PGA and peak ground velocity (PGV recorded by the TSMIP stations reveal a distinct NW-SE-shape pattern from the epicenter area toward the Chiayi region, likely due to the directivity and site effects. Such phenomena should be considered for future regional hazard assessments.

  10. Thermo-kinematic evolution of the Annapurna-Dhaulagiri Himalaya, central Nepal: The Composite Orogenic System

    Science.gov (United States)

    Parsons, A. J.; Law, R. D.; Lloyd, G. E.; Phillips, R. J.; Searle, M. P.

    2016-04-01

    The Himalayan orogen represents a "Composite Orogenic System" in which channel flow, wedge extrusion, and thrust stacking operate in separate "Orogenic Domains" with distinct rheologies and crustal positions. We analyze 104 samples from the metamorphic core (Greater Himalayan Sequence, GHS) and bounding units of the Annapurna-Dhaulagiri Himalaya, central Nepal. Optical microscopy and electron backscatter diffraction (EBSD) analyses provide a record of deformation microstructures and an indication of active crystal slip systems, strain geometries, and deformation temperatures. These data, combined with existing thermobarometry and geochronology data are used to construct detailed deformation temperature profiles for the GHS. The profiles define a three-stage thermokinematic evolution from midcrustal channel flow (Stage 1, >700°C to 550-650°C), to rigid wedge extrusion (Stage 2, 400-600°C) and duplexing (Stage 3, migration of the GHS through these Orogenic Domains and reflects the spatial and temporal variability in rheological boundary conditions that govern orogenic systems.

  11. Australia’s Submarine Design Capabilities and Capacities: Challenges and Options for the Future Submarine

    Science.gov (United States)

    2011-01-01

    General Dynamics Electric Boat Corporation EMC electromagnetic compatibility EMF electromagnetic field EMI electromagnetic interference EPCM engineering...to-diagnose flow-induced radiated noise Own-sensor performance degradation Note: Risks can be reduced for given designs using scale models...Acoustic analysis Addresses the total radiated noise signature of submarine designs Radiated noise that an enemy might detect Self-noise that that

  12. North Sea submarine cable disruptions and fishing activity

    NARCIS (Netherlands)

    Hintzen, N.T.; Machiels, M.A.M.

    2014-01-01

    At the North Sea seafloor, numerous submarine cables are positioned that connect telecommunication networks between countries. Worldwide, human activities cause most of the cable disruptions with fisheries accounting for nearly half of all reported faults. Due to a recent increase of submarine cable

  13. A Case Study of the Activity Gravitational Deformation Slate Slope on One Newly Rebuild Highway Bridge in Taitung Longitudinal Valley of Taiwan

    Science.gov (United States)

    Hsieh, Pei-Chen; Weng, Cheng-Hsueh; Lu, An; Lin, Ming-Lang

    2017-04-01

    There are many landslide hazards induced by typhoon and earthquake in Taiwan because Taiwan is located in active orogen zone, where the Taitung Longitudinal Valley is the plate boundary, and also many typhoons hit Taiwan and bring much precipitation. In Japan, where also is located in orogen zone, the 2016 Kumamoto Earthquake caused a large landslide which destroyed the Great Aso Bridge. It shows that landslides might have huge influence on the safety of bridges. In Sep. 2016, Typhoon No.14 (Meranti) hit Taiwan and caused a slate slope failure which located in Taitung Longitudinal Valley. It cut the approach road of a highway bridge called Songfeng Bridge and the maximum displacement is about 2 meters. The landslide body might include the bridge, and if this landslide continued move the bridge structure might be destroyed. The attitude of cleavage and joints measured in site investigation are complex and confused, it imply that this landslide event is not only controlled by gravitational deformation, but also affected by release joint and river erosion because the site is located on confluence of two river. The target of site investigation in this research includes finding the border of failure surface and the measurement of cleavage and joints. In this research, we compare the result of site investigation and numerical model to find the mechanism of failure, and try to analysis the possible influence on the bridge structure.

  14. Relocation with artificial source in Southern West Taiwan

    Science.gov (United States)

    Hong, Chaug-Ciang; Yen, Horng-Yuan

    2014-05-01

    Taiwan, located on the boundary between the Eurasia plate (EU) and the Philippine Sea plate (PSP), is an orogenic belt formed by the collision between the Luzon Arc and the continental margin. In the previous studies, there have been published many velocity model. It is based on the vast seismic data recorded by Central Weather Bureau Seismic Network (CWBSN) and gives a way to understand subsurface structure. Actually, the distribution of hypocenter can help us to explain the geological structure. But the uncertainty is existed in earthquake location. In this study, we relocate earthquakes between Jan. 2001 to Sep. 2013 from CWSBN using program HYPODD and select an artificial source of Taiwan Integrated Geodynamics Research (TAIGER) to constrain the relocation work. The artificial source Southern 2 (S2) we choose is located in Chiayi in Taiwan Island. Because the known position of artificial source will give a high weighted in located, it will improve the quality of relocation. The program HYPODD determines relative earthquake location within clusters using the double-difference algorithm, developed by Waldhauser and Ellsworth(2000). Firstly, we join the S2 event into the seismic catalog and give a weight for location. Then, we give a medium weight for S2 event for relocation and compare with the results when increasing into better weights of S2 event. The hypocenters of the relocation will be more concentrated to each other and coincide with geological line. It will improve the accuracy of earthquake location and fabric interpretation. References Waldhauser, Felix, and William L. Ellsworth. "A double-difference earthquake location algorithm: Method and application to the northern Hayward fault, California." Bulletin of the Seismological Society of America 90.6 (2000): 1353-1368. Dunn, Meredith M. Relocation of Eastern Tennessee Earthquakes Using hypoDD. Diss. Virginia Polytechnic Institute and State University, 2004.

  15. The 1929 Grand Banks submarine landslide revisited

    Science.gov (United States)

    Schulten, Irena; Mosher, David C.; Krastel, Sebastian; Piper, David J. W.; Kienast, Markus

    2017-04-01

    On November 18th, 1929 a large submarine landslide occurred along the St. Pierre Slope of the southwestern Grand Banks of Newfoundland, as a result of a Mw 7.2 earthquake. This submarine landslide led to the first recognition of naturally-occurring submarine turbidity currents and is one of the few landslides known to have generated a tsunami. The event caused 28 causalities in Newfoundland and severe infrastructural damage. Earlier investigations of the area identified widely distributed shallow mass failures (15 - 20 m high escarpments), but no evidence of a larger headscarp. It is difficult to conceive, therefore, how this distributed shallow failure that rapidly evolved into a turbidity current would have generated a tsunami. It is hypothesised in this study that a deeper rooted sediment failure ( 500 m), involving faulting and mass-rotation, was involved in the sediment failure and this displacement generated the tsunami. In order to test this hypothesis, the volume and kinematics of the 1929 slope failure are analysed by means of recently acquired high resolution seismic reflection and multibeam swath bathymetry data, in addition to a significant volume of legacy data. The data allow determination of: 1) the dimension of the failure area, 2) the thickness and volume of failed sediment on St. Pierre Slope, 3) fault patterns and displacements, and 4) styles of sediment failure involved. Shallow (20 m high) sinuous escarpments and a number of faults are observed along the upper St. Pierre Slope (500 - 2 500 m water depth). The uppermost and largest of these escarpments shows association with a fault system. Preliminary results, therefore, indicate a complex sediment failure pattern along the St. Pierre Slope, possibly involving a deep-seated decollement and mobilization of a large volume of surficial sediment through retrogressive failure. Causes for the tsunami are yet to be determined.

  16. Multivariable Control System Design for a Submarine,

    Science.gov (United States)

    1984-05-01

    perturbations applied to the nominal point were identical in all cases (see table 2.3). The comparisons show excellent correlation between the...Open Loop Singular Values for the 5 and 1S Knot Linear Modelo *~~* b % % V’ , * % ~ .%~ C 9 ~ V. --.- V. V.-.--.--46..- S. 77’ Model S20R5 20- 10- -0...without imparting a pitch angle to the submarine and provides an excellent example of both the usefulness of w(t) as a state variable and the

  17. Hydrogen isotope systematics of submarine basalts

    Science.gov (United States)

    Kyser, T.K.; O'Neil, J.R.

    1984-01-01

    The D/H ratios and water contents in fresh submarine basalts from the Mid-Atlantic Ridge, the East Pacific Rise, and Hawaii indicate that the primary D/H ratios of many submarine lavas have been altered by processes including (1) outgassing, (2) addition of seawater at magmatic temperature, and (3) low-temperature hydration of glass. Decreases in ??D and H2O+ from exteriors to interiors of pillows are explained by outgassing of water whereas inverse relations between ??D and H2O+ in basalts from the Galapagos Rise and the FAMOUS Area are attributed to outgassing of CH4 and H2. A good correlation between ??D values and H2O is observed in a suite of submarine tholeiites dredged from the Kilauea East Rift Zone where seawater (added directly to the magma), affected only the isotopic compositions of hydrogen and argon. Analyses of some glassy rims indicate that the outer millimeter of the glass can undergo lowtemperature hydration by hydroxyl groups having ??D values as low as -100. ??D values vary with H2O contents of subaerial transitional basalts from Molokai, Hawaii, and subaerial alkali basalts from the Society Islands, indicating that the primary ??D values were similar to those of submarine lavas. Extrapolations to possible unaltered ??D values and H2O contents indicate that the primary ??D values of most thoteiite and alkali basalts are near -80 ?? 5: the weight percentages of water are variable, 0.15-0.35 for MOR tholeiites, about 0.25 for Hawaiian tholeiites, and up to 1.1 for alkali basalts. The primary ??D values of -80 for most basalts are comparable to those measured for deep-seated phlogopites. These results indicate that hydrogen, in marked contrast to other elements such as Sr, Nd, Pb, and O, has a uniform isotopic composition in the mantle. This uniformity is best explained by the presence of a homogeneous reservoir of hydrogen that has existed in the mantle since the very early history of the Earth. ?? 1984.

  18. Critical elements in Carlin, epithermal, and orogenic gold deposits

    Science.gov (United States)

    Goldfarb, Richard J.; Hofstra, Albert H.; Simmons, Stuart F.

    2016-01-01

    Carlin, epithermal, and orogenic gold deposits, today mined almost exclusively for their gold content, have similar suites of anomalous trace elements that reflect similar low-salinity ore fluids and thermal conditions of metal transport and deposition. Many of these trace elements are commonly referred to as critical or near-critical elements or metals and have been locally recovered, although typically in small amounts, by historic mining activities. These elements include As, Bi, Hg, In, Sb, Se, Te, Tl, and W. Most of these elements are now solely recovered as by-products from the milling of large-tonnage, base metal-rich ore deposits, such as porphyry and volcanogenic massive sulfide deposits.A combination of dominance of the world market by a single country for a single commodity and a growing demand for many of the critical to near-critical elements could lead to future recovery of such elements from select epithermal, orogenic, or Carlin-type gold deposits. Antimony continues to be recovered from some orogenic gold deposits and tellurium could potentially be a primary commodity from some such deposits. Tellurium and indium in sphalerite-rich ores have been recovered in the past and could be future commodities recovered from epithermal ores. Carlin-type gold deposits in Nevada are enriched in and may be a future source for As, Hg, Sb, and/or Tl. Some of the Devonian carbonaceous host rocks in the Carlin districts are sufficiently enriched in many trace elements, including Hg, Se, and V, such that they also could become resources. Thallium may be locally enriched to economic levels in Carlin-type deposits and it has been produced from Carlin-like deposits elsewhere in the world (e.g., Alsar, southern Macedonia; Lanmuchang, Guizhou province, China). Mercury continues to be recovered from shallow-level epithermal deposits, as well as a by-product of many Carlin-type deposits where refractory ore is roasted to oxidize carbon and pyrite, and mercury is then

  19. Isotopic evidence for the influence of typhoons and submarine canyons on the sourcing and transport behavior of biospheric organic carbon to the deep sea

    Science.gov (United States)

    Zheng, Li-Wei; Ding, Xiaodong; Liu, James T.; Li, Dawei; Lee, Tsung-Yu; Zheng, Xufeng; Zheng, Zhenzhen; Xu, Min Nina; Dai, Minhan; Kao, Shuh-Ji

    2017-05-01

    Export of biospheric organic carbon from land masses to the ocean plays an important role in regulating the global carbon cycle. High-relief islands in the western Pacific are hotspots for such land-to-ocean carbon transport due to frequent floods and active tectonics. Submarine canyon systems serve as a major conduit to convey terrestrial organics into the deep sea, particularly during episodic floods, though the nature of ephemeral sediment transportation through such canyons remains unclear. In this study, we deployed a sediment trap in southwestern Taiwan's Gaoping submarine canyon during summer 2008, during which Typhoon Kalmaegi impacted the study area. We investigated sources of particulate organic carbon and quantified the content of fossil organic carbon (OCf) and biospheric non-fossil carbon (OCnf) during typhoon and non-typhoon periods, based on relations between total organic carbon (TOC), isotopic composition (δ13 C, 14C), and nitrogen to carbon ratios (N/C) of newly and previously reported source materials. During typhoons, flooding connected terrestrial rivers to the submarine canyon. Fresh plant debris was not found in the trap except in the hyperpycnal layer, suggesting that only hyperpycnal flow is capable of entraining plant debris, while segregation had occurred during non-hyperpycnal periods. The OCnf components in typhoon flood and trapped samples were likely sourced from aged organics buried in ancient landslides. During non-typhoon periods, the canyon is more connected to the shelf, where waves and tides cause reworking, thus allowing abiotic and biotic processes to generate isotopically uniform and similarly aged OCnf for transport into the canyon. Therefore, extreme events coupled with the submarine canyon system created an efficient method for deep-sea burial of freshly produced organic-rich material. Our results shed light on the ephemeral transport of organics within a submarine canyon system on an active tectonic margin.

  20. Flow dynamics around downwelling submarine canyons

    Directory of Open Access Journals (Sweden)

    J. M. Spurgin

    2014-10-01

    Full Text Available Flow dynamics around a downwelling submarine canyon were analysed with the Massachusetts Institute of Technology general circulation model. Blanes Canyon (northwestern Mediterranean was used for topographic and initial forcing conditions. Fourteen scenarios were modelled with varying forcing conditions. Rossby and Burger numbers were used to determine the significance of Coriolis acceleration and stratification (respectively and their impacts on flow dynamics. A new non-dimensional parameter (χ was introduced to determine the significance of vertical variations in stratification. Some simulations do see brief periods of upwards displacement of water during the 10-day model period; however, the presence of the submarine canyon is found to enhance downwards advection of density in all model scenarios. High Burger numbers lead to negative vorticity and a trapped anticyclonic eddy within the canyon, as well as an increased density anomaly. Low Burger numbers lead to positive vorticity, cyclonic circulation, and weaker density anomalies. Vertical variations in stratification affect zonal jet placement. Under the same forcing conditions, the zonal jet is pushed offshore in more uniformly stratified domains. The offshore jet location generates upwards density advection away from the canyon, while onshore jets generate downwards density advection everywhere within the model domain. Increasing Rossby values across the canyon axis, as well as decreasing Burger values, increase negative vertical flux at shelf break depth (150 m. Increasing Rossby numbers lead to stronger downwards advection of a passive tracer (nitrate, as well as stronger vorticity within the canyon. Results from previous studies are explained within this new dynamic framework.

  1. Submarine Tailings Disposal (STD—A Review

    Directory of Open Access Journals (Sweden)

    Bernhard Dold

    2014-07-01

    Full Text Available The mining industry is a fundamental industry involved in the development of modern society, but is also the world’s largest waste producer. This role will be enhanced in the future, because ore grades are generally decreasing, thus leading to increases in the waste/metal production ratio. Mine wastes deposited on-land in so-called tailings dams, impoundments or waste-dumps have several associated environmental issues that need to be addressed (e.g., acid mine drainage formation due to sulphide oxidation, geotechnical stability, among others, and social concerns due to land use during mining. The mining industry recognizes these concerns and is searching for waste management alternatives for the future. One option used in the past was the marine shore or shallow submarine deposition of this waste material in some parts of the world. After the occurrence of some severe environmental pollution, today the deposition in the deep sea (under constant reducing conditions is seen as a new, more secure option, due to the general thought that sulphide minerals are geochemically stable under the reduced conditions prevailing in the deep marine environment. This review highlights the mineralogical and geochemical issues (e.g., solubility of sulphides in seawater; reductive dissolution of oxide minerals under reducing conditions, which have to be considered when evaluating whether submarine tailings disposal is a suitable alternative for mine waste.

  2. Submarine melt rates under Greenland's ice tongues

    Science.gov (United States)

    Wilson, Nat; Straneo, Fiametta; Heimbach, Patrick; Cenedese, Claudia

    2017-04-01

    The few remaining ice tongues (ice-shelf like extensions) of Greenland's glaciers are undergoing rapid changes with potential implications for the stability of the ice sheet. Submarine melting is recognized as a major contributor to mass loss, yet the magnitude and spatial distribution of melt are poorly known or understood. Here, we use high resolution satellite imagery to infer the magnitude and spatial variability of melt rates under Greenland's largest remaining ice tongues: Ryder Glacier, Petermann Glacier and Nioghalvfjerdsbræ (79 North Glacier). We find that submarine plus aerial melt approximately balance the ice flux from the grounded ice sheet for the first two while at Nioghalvfjerdsbræ the total melt flux exceeds the inflow of ice indicating thinning of the ice tongue. We also show that melt rates under the ice tongues vary considerably, exceeding 60 m yr-1 near the grounding zone and decaying rapidly downstream. Channels, likely originating from upstream subglacial channels, give rise to large melt variations across the ice tongues. Using derived melt rates, we test simplified melt parameterizations appropriate for ice sheet models and find the best agreement with those that incorporate ice tongue geometry in the form of depth and slope.

  3. Environmental assessment of submarine power cables

    Energy Technology Data Exchange (ETDEWEB)

    Isus, Daniel; Martinez, Juan D. [Grupo General Cable Sistemas, S.A., 08560-Manlleu, Barcelona (Spain); Arteche, Amaya; Del Rio, Carmen; Madina, Virginia [Tecnalia Research and Innovation, 20009 San Sebastian (Spain)

    2011-03-15

    Extensive analyses conducted by the European Community revealed that offshore wind energy have relatively benign effects on the marine environment by comparison to other forms of electric power generation [1]. However, the materials employed in offshore wind power farms suffer major changes to be confined to the marine environment at extreme conditions: saline medium, hydrostatic pressure... which can produce an important corrosion effect. This phenomenon can affect on the one hand, to the material from the structural viewpoint and on the other hand, to the marine environment. In this sense, to better understand the environmental impacts of generating electricity from offshore wind energy, this study evaluated the life cycle assessment for some new designs of submarine power cables developed by General Cable. To achieve this goal, three approaches have been carried out: leaching tests, eco-toxicity tests and Life Cycle Assessment (LCA) methodologies. All of them are aimed to obtaining quantitative data for environmental assessment of selected submarine cables. LCA is a method used to assess environmental aspects and potential impacts of a product or activity. LCA does not include financial and social factors, which means that the results of an LCA cannot exclusively form the basis for assessment of a product's sustainability. Leaching tests results allowed to conclude that pH of seawater did not significantly changed by the presence of submarine three-core cables. Although, it was slightly higher in case of broken cable, pH values were nearly equals. Concerning to the heavy metals which could migrate to the aquatic medium, there were significant differences in both scenarios. The leaching of zinc is the major environmental concern during undersea operation of undamaged cables whereas the fully sectioned three-core cable produced the migration of significant quantities of copper and iron apart from the zinc migrated from the galvanized steel. Thus, the tar

  4. Synorogenic collapse: a perspective from the middle crust, the proterozoic grenville orogen.

    Science.gov (United States)

    Mezger, K; VAN DER Pluijm, B A; Essene, E J; Halliday, A N

    1991-11-01

    Structural, petrological, and geochronological studies of the middle to late Proterozoic Grenville orogen in Ontario, Canada, indicate that a major extensional fault developed synchronously with late thrusting. This fault zone was initiated during peak metamorphism and extended into the crust to depths of at least 25 kilometers. The temporal and spatial relations among faulting, metamorphism, and regional compression indicate that synorogenic collapse initiated because the crust exceeded the maximum physiographic height and thickness that could be supported by its rheology. Comparison of Grenville with recent Himalayan orogenic activity suggests that during Proterozoic times physiographic height, crustal thickness, and crustal strength were similar to modern conditions in orogenic belts.

  5. Navy Ohio Replacement (SSBN[X]) Ballistic Missile Submarine Program: Background and Issues for Congress

    Science.gov (United States)

    2015-12-17

    propulsion technology first occurred many years ago: To help jumpstart the UK’s nuclear - powered submarine program, the United States transferred to the UK a... nuclear - powered attack submarines (SSNs), nuclear - powered cruise missile submarines (SSGNs), and nuclear - powered ballistic missile submarines (SSBNs). 2...2 In the designations SSN, SSGN, SSBN, and SSBN(X), the SS stands for submarine, N stands for nuclear - powered (meaning the ship is

  6. Space programs in Taiwan

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Lou-Chuang [Academia Sinica, Institute of Earth Sciences, 128, Sec. 2, Academia Road, Nangang, Taipei 115, Taiwan (China); Institute of Space Science, National Central University, 300, Jhongda Rd., Jhongli City, Taoyuan County 32001, Taiwan (China); Chang, Guey-Shin, E-mail: gschang@nspo.narl.org.tw [National Space Organization, 8F, 9 Prosperity 1st Rd., Hsinchu Science Park, Hsinchu 30078, Taiwan (China); Ting, Nan-Hong [National Applied Research Laboratories, 3F, 106, Sec. 2, Hepin East Rd., Taipei 10622, Taiwan (China)

    2013-10-15

    Taiwan's current and future space programs are briefly introduced in this paper. The National Space Organization (NSPO) in Taiwan has successfully carried out three satellite programs (FORMOSAT-1, 2, and 3) since its establishment in 1991. FORMOSAT-1 is a scientific satellite performing three scientific experiments for measuring the density, velocity and temperature of ionospheric plasmas, taking the ocean color image, and conducting Ka-band communication experiments. Equipped with a 2m ground resolution remote sensing instrument, FORMOSAT-2 operates in a sun-synchronous orbit with revisit time equal to one day. This unique feature of the daily revisit capability is significantly useful for post disaster assessment and environmental monitoring. FORMOSAT-2 also carries a scientific payload “Imager of Sprites and Upper Atmospheric Lightning (ISUAL)”. ISUAL provides the world's first long-term satellite observations on the lighting phenomenon in the earth's upper atmosphere. FORMOSAT-3 is a constellation of six micro-satellites to collect atmospheric and ionospheric data for weather prediction and for climate, ionosphere, and geodesy research. FORMOSAT-3 has demonstrated the ability to significantly increase the accuracy of weather forecasting by utilizing the GPS Radio Occultation (GPS-RO) technique. Currently, NSPO is pursuing the follow-on space missions of FORMOSAT-5 and FORMOSAT-7. FORMOSAT-5 will be the first to utilize a CMOS detector on a high-resolution earth-observation camera. FORMOSAT-7 is a joint mission of Taiwan/US to deploy a 12-satellite constellation operational system to provide dense and timely GNSS RO data to the global communities for real-time weather forecast as well as space science research.

  7. Submarine landside in the Bussol Graben: Structural and formation features

    Science.gov (United States)

    Baranov, B. V.; Lobkovsky, L. I.; Dozorova, K. A.; Rukavishnikova, D. D.

    2017-05-01

    Analysis of geophysical data obtained during a study of the insular slope in the central Kuril‒Kamchatka Trench during projects Kuriles-2005 and Kuriles-2006 promoted by the Presidium of the Russian Academy of Sciences revealed a large submarine landslide in this area. The landslide, located at the bottom of the transverse valley confined to the Bussol l Graben, resulted from the failure of the northeastern wall of a graben composed of sedimentary material. It exceeds 35 km3 in size, representing one of the large submarine landslides discovered to date on the slope of the Kuril‒Kamchatka Trench in submarine canyonfan environments.

  8. Management of demand based inventory aboard submarine tenders servicing attack (SSN) submarines

    OpenAIRE

    Ross, Timothy Joseph

    1990-01-01

    Approved for public release; distribution is unlimited. This thesis examines the computation of inventory levels based on demand history aboard Submarine Tenders that use the Shipboard Automated Data Processing System (SUADPS) for inventory control. The focus of the thesis was the workload and supply effectiveness issues associated with the processing of the SUADPS levels setting program. The objective of the thesis was to determine the effect on supply effectiveness and stock churn if the...

  9. Submarine thermal springs on the Galapagos Rift

    Science.gov (United States)

    Corliss, J.B.; Dymond, J.; Gordon, L.I.; Edmond, J.M.; Von Herzen, R. P.; Ballard, Richard D.; Green, K.; Williams, D.; Bainbridge, A.; Crane, K.; Van Andel, T. H.

    1979-01-01

    The submarine hydrothermal activity on and near the Galápagos Rift has been explored with the aid of the deep submersible Alvin. Analyses of water samples from hydrothermal vents reveal that hydrothermal activity provides significant or dominant sources and sinks for several components of seawater; studies of conductive and convective heat transfer suggest that two-thirds of the heat lost from new oceanic lithosphere at the Galápagos Rift in the first million years may be vented from thermal springs, predominantly along the axial ridge within the rift valley. The vent areas are populated by animal communities. They appear to utilize chemosynthesis by sulfur-oxidizing bacteria to derive their entire energy supply from reactions between the seawater and the rocks at high temperatures, rather than photosynthesis

  10. EARLY PRECAMBRIAN CRUSTAL EVOLUTION OF THE BELOMORIAN AND TRANS-NORTH CHINA OROGENS AND SUPERCONTINENTS RECONSTRUCTION

    Directory of Open Access Journals (Sweden)

    A. I. Slabunov

    2017-01-01

    Full Text Available Comparative analysis of the crustal evolution of the Early Precambrian Belomorian and Trans-North China orogens (Fig. 1 has shown [Slabunov et al., 2015] that: Both belts were formed by the superposition of two Precambrian orogenies. The earth crust of the Belomorian belt was produced during the Mesoarchaean to Neoarchaean Belomorian collisional orogeny [Slabunov, 2008; Slabunov et al., 2006] and then was reworked during the Palaeoproterozoic Lapland-Kola collisional orogeny [Daly at al., 2006; Balagansky et al., 2014]. The earth crust of the Trans-North China orogen was formed during a Neoarchean accretionary orogeny and then was reworked during a Paleoproterozoic collisional orogeny [Zhao et al., 2012; Guo et al., 2012, 2005]. The Lapland granulite belt is the core of the Lapland-Kola Palaeoproterozoic collisional orogen in the Fennoscandian shield and the Khondolite belt occupies the same tectonic position in a Palaeoproterozoic collisional orogen in the North China craton.

  11. Geodynamics of a cordilleran orogenic system: the central Andes of Argentina and northern Chile

    National Research Council Canada - National Science Library

    DeCelles, Peter G

    2015-01-01

    "This memoir brings together results from a multidisciplinary study of the processes that have formed the highest, widest part of the Andean Cordilleran orogenic belt in northern Argentina and Chile...

  12. Improved OTEC System for a Submarine Robot

    Science.gov (United States)

    Chao, Yi; Jones, Jack; Valdez, Thomas

    2010-01-01

    An ocean thermal energy conversion (OTEC), now undergoing development, is a less-massive, more-efficient means of exploiting the same basic principle as that of the proposed system described in "Alternative OTEC Scheme for a Submarine Robot" (NPO-43500), NASA Tech Briefs, Vol. 33, No. 1 (January 2009), page 50. The proposed system as described previously would be based on the thawing-expansion/freezing-contraction behavior of a wax or perhaps another suitable phase-change material (PCM). The power generated by the system would be used to recharge the batteries in a battery- powered unmanned underwater vehicle [UUV (essentially, a small exploratory submarine robot)] of a type that has been deployed in large numbers in research pertaining to global warming. A UUV of this type travels between the ocean surface and depths, measuring temperature and salinity. At one phase of its operational cycle, the previously proposed system would utilize the surface ocean temperature (which lies between 15 and 30 C over most of the Earth) to melt a PCM that has a melting/freezing temperature of about 10 C. At the opposite phase of its operational cycle, the system would utilize the lower ocean temperature at depth (e.g., between 4 and 7 C at a depth of 300 m) to freeze the PCM. The melting or freezing would cause the PCM to expand or contract, respectively, by about 9 volume percent. The PCM would be contained in tubes that would be capable of expanding and contracting with the PCM. The PCM-containing tubes would be immersed in a hydraulic fluid. The expansion and contraction would drive a flow of the hydraulic fluid against a piston that, in turn, would push a rack-and-pinion gear system to spin a generator to charge a battery.

  13. Pn tomography of South China Sea, Taiwan Island, Philippine archipelago, and adjacent regions

    Science.gov (United States)

    Li, Xibing; Song, Xiaodong; Li, Jiangtao

    2017-02-01

    The South China Sea (SCS) and its surrounding areas are geologically highly heterogeneous from the interactions of multiple plates in Southeast Asia (Eurasian plate, Indian-Australian plate, Philippine Sea plate, and Pacific plate). To understand the tectonics at depth, here we combined bulletin and handpicked data to conduct Pn tomography of the region. The results show distinct features that are correlated with the complex geology at surface, suggesting a lithosphere-scale tectonics of the region. Low Pn velocities are found along a belt of the western Pacific transpressional system from the Okinawa Trough and eastern East China Sea, across central and eastern Taiwan orogeny, to the island arcs of the Luzon Strait and the entire Philippine Islands, as well as under the Palawan Island and part of the continental margin north of the Pearl River Basin. High velocities are found under Ryukyu subduction zone, part of the Philippine subduction zone, part of the Eurasian subduction beneath the southwestern Taiwan, and the continent-ocean boundary between the south China and the SCS basin. The Taiwan Strait, the Mainland SE coast, and the main SCS basin sea are relatively uniform with average Pn values. Crustal thicknesses show large variations in the study region but also coherency with tectonic elements. The Pn pattern in Taiwan shows linear trends of surface geology and suggests strongly lithosphere-scale deformation of the young Taiwan orogenic belt marked by the deformation boundary under the Western Foothill and the Western Coastal Plain at depth, and the crustal thickness shows a complex pattern from the transpressional collision. Our observations are consistent with rifting and extension in the northern margin of the SCS but are not consistent with mantle upwelling as a mechanism for the opening and the subsequent closing of the SCS. The Philippine island arc is affected by volcanisms from both the Asian and Philippine Sea subductions in the south but mainly from

  14. Improved alignment of the Hengchun Fault (southern Taiwan) based on fieldwork, structure-from-motion, shallow drilling, and levelling data

    Science.gov (United States)

    Giletycz, Slawomir Jack; Chang, Chung-Pai; Lin, Andrew Tien-Shun; Ching, Kuo-En; Shyu, J. Bruce H.

    2017-11-01

    The fault systems of Taiwan have been repeatedly studied over many decades. Still, new surveys consistently bring fresh insights into their mechanisms, activity and geological characteristics. The neotectonic map of Taiwan is under constant development. Although the most active areas manifest at the on-land boundary of the Philippine Sea Plate and Eurasia (a suture zone known as the Longitudinal Valley), and at the southwestern area of the Western Foothills, the fault systems affect the entire island. The Hengchun Peninsula represents the most recently emerged part of the Taiwan orogen. This narrow 20-25 km peninsula appears relatively aseismic. However, at the western flank the peninsula manifests tectonic activity along the Hengchun Fault. In this study, we surveyed the tectonic characteristics of the Hengchun Fault. Based on fieldwork, four years of monitoring fault displacement in conjunction with levelling data, core analysis, UAV surveys and mapping, we have re-evaluated the fault mechanisms as well as the geological formations of the hanging and footwall. We surveyed features that allowed us to modify the existing model of the fault in two ways: 1) correcting the location of the fault line in the southern area of the peninsula by moving it westwards about 800 m; 2) defining the lithostratigraphy of the hanging and footwall of the fault. A bathymetric map of the southern area of the Hengchun Peninsula obtained from the Atomic Energy Council that extends the fault trace offshore to the south distinctively matches our proposed fault line. These insights, coupled with crust-scale tomographic data from across the Manila accretionary system, form the basis of our opinion that the Hengchun Fault may play a major role in the tectonic evolution of the southern part of the Taiwan orogen.

  15. Tectonic stress evolution in the Pan-African Lufilian Arc and its foreland (Katanga, DRC): orogenic bending, late orogenic extensional collapse and transition to rifting

    Science.gov (United States)

    Kipata, M. L.; Delvaux, D.; Sebagenzi, M. N.; Cailteux, J.; Sintubin, M.

    2012-04-01

    Between the paroxysm of the Lufilian orogeny at ~ 550 Ma and the late Neogene to Quaternary development of the south-western branch of the East African rift system, the tectonic evolution of the Lufilian Arc and Kundelungu foreland in the Katanga region of the Democratic Republic of Congo remains poorly unknown although it caused important Cu-dominated mineral remobilizations leading to world-class ore deposits. This long period is essentially characterized by brittle tectonic deformations that have been investigated by field studies in open mines spread over the entire arc and foreland. Paleostress tensors were computed for a database of 1450 fault-slip data by interactive stress tensor inversion and data subset separation, and the relative succession of 8 brittle deformation events established. The oldest brittle structures observed are related to the Lufilian brittle compressional climax (stage 1). They have been re-oriented during the orogenic bending that led to the arcuate shape of the belt. Unfolding the stress directions from the first stage allows to reconstruct a consistent NE-SW direction of compression for this stage. Constrictional deformation occurred in the central part of the arc, probably during orogenic bending (Stage 2). After the orogenic bending, a sequence of 3 deformation stages marks the progressive onset of late-orogenic extension: strike-slip deformations (stages 3-4) and late-orogenic arc-parallel extension (stage 5). It is proposed that these 3 stages correspond to orogenic collapse. In early Mesozoic, NW-SE compression was induced by a transpressional inversion, interpreted as induced by far-field stresses generated at the southern active margin of Gondwana (stage 6). Since then, this region was affected by rift-related extension, successively in a NE-SW direction (stage 7, Tanganyika trend) and NW-SE direction (stage 8, Moero trend).

  16. Shear-wave velocity of marine sediments offshore Taiwan using ambient seismic noise

    Science.gov (United States)

    Lin, Yu-Tse; Lin, Jing-Yi; Kuo-Chen, Hao; Yeh, Yi-Chin; Cheng, Win-Bin

    2017-04-01

    Seismic ambient noise technology has many advantages over the traditional two-station method. The most important one is that noise is happening all the time and it can be widely and evenly distributed. Thus, the Green's Function of any station pair can be obtained through the data cross-correlation process. Many related studies have been performed to estimate the velocity structures based on the inland area. Only a few studies were reported for the marine area due to the relatively shorter recording time of ocean bottom seismometers (OBS) deployment and the high cost of the marine experiment. However, the understanding about the shear-wave velocity (Vs) of the marine sediments is very crucial for the hazard assessment related to submarine landslides, particularly with the growing of submarine resources exploration. In this study, we applied the ambient noise technique to four OBS seismic networks located offshore Taiwan in the aim of getting more information about the noise sources and having the preliminary estimation for the Vs of the marine sediments. Two of the seismic networks were deployed in the NE part of Taiwan, near the Ryukyu subduction system, whereas the others were in the SW area, on the continental margin rich in gas hydrate. Generally, ambient seismic noise could be associated with wind, ocean waves, rock fracturing and anthropogenic activity. In the southwestern Taiwan, the cross-correlation function obtained from two seismic networks indicate similar direction, suggestion that the source from the south part of the network could be the origin of the noise. However, the two networks in the northeastern Taiwan show various source direction, which could be caused by the abrupt change of bathymetry or the volcanic degassing effect frequently observed by the marine geophysical method in the area. The Vs determined from the dispersion curve shows a relatively higher value for the networks in the Okinawa Trough (OT) off NE Taiwan than that in the

  17. A model for tidewater glacier undercutting by submarine melting

    Science.gov (United States)

    Slater, D. A.; Nienow, P. W.; Goldberg, D. N.; Cowton, T. R.; Sole, A. J.

    2017-03-01

    Dynamic change at the marine-terminating margins of the Greenland Ice Sheet may be initiated by the ocean, particularly where subglacial runoff drives vigorous ice-marginal plumes and rapid submarine melting. Here we model submarine melt-driven undercutting of tidewater glacier termini, simulating a process which is key to understanding ice-ocean coupling. Where runoff emerges from broad subglacial channels we find that undercutting has only a weak impact on local submarine melt rate but increases total ablation by submarine melting due to the larger submerged ice surface area. Thus, the impact of melting is determined not only by the melt rate magnitude but also by the slope of the ice-ocean interface. We suggest that the most severe undercutting occurs at the maximum height in the fjord reached by the plume, likely promoting calving of ice above. It remains unclear, however, whether undercutting proceeds sufficiently rapidly to influence calving at Greenland's fastest-flowing glaciers.

  18. Submarine Upward Looking Sonar Ice Draft Profile Data and Statistics

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set consists of upward looking sonar draft data collected by submarines in the Arctic Ocean. It includes data from both U.S. Navy and Royal Navy...

  19. Virtual Reality Training System for a Submarine Command Center

    National Research Council Canada - National Science Library

    Maxwell, Douglas B

    2008-01-01

    The invention as disclosed is a system that uses a combined real and virtual display interaction methodology to generate the visual appearance of submarine combat control rooms and allow interaction...

  20. Studies on submarine control for periscope depth operations

    OpenAIRE

    Tolliver, John V.

    1996-01-01

    Approved for public release; distribution in unlimited. Requirements for submarine periscope depth operations have been increased by integration with carrier battle groups, littoral operations, and contributions to joint surveillance. Improved periscope depth performance is therefore imperative. Submarine control personnel rely on a large number of analog gauges and indications. An integrated digital display system could enhance the ergonomics of the human control interface and display add...

  1. Exercise Aboard Attack Submarines: Rationale and New Options

    Science.gov (United States)

    2004-08-18

    experience loss of physical fitness while underway. Bennett and co-workers (2) noted a 7% reduction of maximal oxygen consumption in non-exercising...Inc. designed and built a comprehensive resistance exercise device to help counteract muscle deconditioning during long term space flights (the SX... Physical activity aboard nuclear submarines as measured by pedometry. Groton: Naval Submarine Medical Research Laboratory, Report 1053, 1985, p. 12

  2. Are tilt measurements useful in detecting tsunamigenic submarine landslides?

    OpenAIRE

    Sascha Brune; Andrey Babeyko; Stephan V. Sobolev

    2009-01-01

    Large submarine landslides can generate dangerous tsunamis. Because of their long-period signal, detection of landslides by common seismological methods is difficult. Here we suggest a method of detecting submarine landslides by using an array of land-based tiltmeters. The displacement of a large volume of sediments during landsliding produces a detectable elastic response of the lithosphere. We propose a technique to calculate this response and to invert for tsunami relevant parameters like ...

  3. Accessing The Fourth Dimension In Orogenic Reconstruction Using Granitoid Thermobarometry

    Science.gov (United States)

    Alexander, E.; Wielicki, M. M.; Harrison, M.; Lovera, O. M.; DePaolo, D.

    2016-12-01

    Tectonic models for the Tibetan-Himalayan orogen predict very different crustal thickness histories, providing a possible test of these various hypotheses. However, reconstructing the evolution of the Tibetan-Himalayan crust is a four-dimensional problem. Knowing the 2D distribution of U-Pb zircon dated samples permits insights into changes in magmatic style, but understanding of N-S thickening history requires depth information. In S. Tibet, voluminous granitoids emplaced between 200-20 Ma provides a spatiotemporal window into the tectonic evolution of the Tibetan crust. A thermoisotopic model utilizing systematic N-S ɛNd variations as a crustal thickness proxy indicates that, at the time of collision, the crust beneath the Indus-Tsangpo suture was relatively thin ( 20 km), increasing to >45 km 100 km to the N. Given evidence of little post-50 Ma upper-crustal shortening, the Tibetan crust appears to have reached its present 85 km thickness via 20 km of tectonic accretion, 15 km of juvenile magma input, as well as the underthrusted Indian crust. Since zircon ɛHf correlates well with whole rock ɛNd, using it together with in situ δ18O, Ti-thermometry and trace element analyses, has provided a refined picture of the relative roles of assimilation and recharge in granitoid formation. To understand the spatiotemporal progression of thickening, we utilize two thermobarometers to reconstruct crystallization depths: Al-in-hornblende and Ti-in-quartz. While Al-in-hornblende has been more widely tested on igneous systems, our data show that it may be sensitive to closure effects during high T storage and hydrothermal alteration. In contrast, Ti-in-quartz preserves magmatic Ti signatures, and quartz's exclusive structure and resistance to alteration provides a more robust proxy for emplacement conditions. Using these thermobarometers in conjunction with Ti-in-zircon thermometry can establish emplacement depth of syn-collisional Lhasa block granites providing the missing

  4. An Experimental Multi-disciplinary observatory (VENUS at the Ryukyu Trench using the Guam-Okinawa Geophysical Submarine Cable

    Directory of Open Access Journals (Sweden)

    Y. Shirasaki

    2006-06-01

    Full Text Available A multidisciplinary Ocean Bottom Observatory (MDOBO was installed on VENUS (Versatile Eco-monitoring Network by Undersea-cable System a depth of 2,170 meters on the slope of the Ryukyu Trench. In this context, “Eco-“ refers to both economic (e.g., earthquake hazard mitigation and ecological motivation. The first step in this instillation was to insert a telemetry/power system into the submarine coaxial cable; this system could then service the MODOBO, which consist of seven major bottom sensor packages. During August-September 1999, using a deep-towed unit and both manned and unmanned submersibles coupled with precise ship navigation, the MDOBO system and its attendant cables were deployed over a range of distances from 80 m to 1 km from the telemetry system, with several meter allowance for navigational uncertainty in positioning. The unmanned submersible then extended the multi-conductor extension cables from the instrument units toward the telemetry system and connected them to undersea mateable connectors on a junction box installed on the submarine cable. The MDOBO collected one and half months of continuous records. Several kinds of useful data were collected after installation, including an aftershock (Ms=6.1 of the 1999 Chi-Chi earthquake (Ms=7.7 in Taiwan.

  5. The development of permafrost bacterial communities under submarine conditions

    Science.gov (United States)

    Mitzscherling, Julia; Winkel, Matthias; Winterfeld, Maria; Horn, Fabian; Yang, Sizhong; Grigoriev, Mikhail N.; Wagner, Dirk; Overduin, Pier P.; Liebner, Susanne

    2017-07-01

    Submarine permafrost is more vulnerable to thawing than permafrost on land. Besides increased heat transfer from the ocean water, the penetration of salt lowers the freezing temperature and accelerates permafrost degradation. Microbial communities in thawing permafrost are expected to be stimulated by warming, but how they develop under submarine conditions is completely unknown. We used the unique records of two submarine permafrost cores from the Laptev Sea on the East Siberian Arctic Shelf, inundated about 540 and 2500 years ago, to trace how bacterial communities develop depending on duration of the marine influence and pore water chemistry. Combined with geochemical analysis, we quantified total cell numbers and bacterial gene copies and determined the community structure of bacteria using deep sequencing of the bacterial 16S rRNA gene. We show that submarine permafrost is an extreme habitat for microbial life deep below the seafloor with changing thermal and chemical conditions. Pore water chemistry revealed different pore water units reflecting the degree of marine influence and stages of permafrost thaw. Millennia after inundation by seawater, bacteria stratify into communities in permafrost, marine-affected permafrost, and seabed sediments. In contrast to pore water chemistry, the development of bacterial community structure, diversity, and abundance in submarine permafrost appears site specific, showing that both sedimentation and permafrost thaw histories strongly affect bacteria. Finally, highest microbial abundance was observed in the ice-bonded seawater unaffected but warmed permafrost of the longer inundated core, suggesting that permafrost bacterial communities exposed to submarine conditions start to proliferate millennia after warming.

  6. Cardiometabolic Health in Submariners Returning from a 3-Month Patrol

    Directory of Open Access Journals (Sweden)

    Heath G. Gasier

    2016-02-01

    Full Text Available Confined space, limited exercise equipment, rotating shift work and reduced sleep may affect cardiometabolic health in submariners. To test this hypothesis, 53 male U.S. Submariners (20–39 years were studied before and after a 3-month routine submarine patrol. Measures included anthropometrics, dietary and physical activity, biomarkers of cardiometabolic health, energy and appetite regulation, and inflammation. Before deployment, 62% of submariners had a body fat % (BF% ≥ 25% (obesity, and of this group, 30% met the criteria for metabolic syndrome. In obese volunteers, insulin, the homeostatic model assessment of insulin resistance (HOMA-IR, leptin, the leptin/adiponectin ratio, and pro-inflammatory chemokines growth-related oncogene and macrophage-derived chemokine were significantly higher compared to non-obese submariners. Following the patrol, a significant mean reduction in body mass (5% and fat-mass (11% occurred in the obese group as a result of reduced energy intake (~2000 kJ during the patrol; and, independent of group, modest improvements in serum lipids and a mean reduction in interferon γ-induced protein 10 and monocyte chemotactic protein 1 were observed. Since 43% of the submariners remained obese, and 18% continued to meet the criteria for metabolic syndrome following the patrol, the magnitude of weight loss was insufficient to completely abolish metabolic dysfunction. Submergence up to 3-months, however, does not appear to be the cause of obesity, which is similar to that of the general population.

  7. Solution of Supplee's submarine paradox through special and general relativity

    CERN Document Server

    Vieira, R S

    2016-01-01

    In 1989 Supplee described an apparent relativistic paradox on which a submarine seems to sink in a given frame while floating in another one. If the submarine density is adjusted to be the same as the water density (when both of them are at rest) and then it is put to move, the density of the submarine will become higher than that of the water, thanks to Lorentz contraction, and hence it sinks. However, in the submarine proper frame, is the water that becomes denser, so the submarine supposedly should float and we get a paradox situation. In this paper we analyze the submarine paradox in both a flat and a curved spacetime. In the case of a flat spacetime, we first show that any relativistic force field in special relativity can be written in the Lorentz form, so that it can always be decomposed into a static (electric-like) and a dynamic (magnetic-like) part. Taking into account the gravitomagnetic effects between the Earth and the water, a relativistic formulation of Archimedes principle can be established, ...

  8. New insights on the petrology of submarine volcanics from the Western Pontine Archipelago (Tyrrhenian Sea, Italy)

    Science.gov (United States)

    Conte, A. M.; Perinelli, C.; Bianchini, G.; Natali, C.; Martorelli, E.; Chiocci, F. L.

    2016-11-01

    The Pontine Islands form a volcanic archipelago in the Tyrrhenian Sea. It consists of two edifices, the islands of Ponza, Palmarola and Zannone and the islands of Ventotene and Santo Stefano, respectively. The Archipelago developed during two main volcanic cycles in the Plio-Pleistocene: 1) the Pliocene episode erupted subalkaline, silica-rich volcanic units, which constitute the dominant products in the western edifice (Ponza and Zannone Islands); 2) the Pleistocene episode erupted more alkaline products, represented by evolved rocks (trachytes to peralkaline rhyolites) in the islands of Ponza and Palmarola and by basic to intermediate rocks in the eastern edifice (Ventotene and Santo Stefano Islands). In this paper we present new geochemical and petrological data from submarine rock samples collected in two oceanographic cruises and a scuba diving survey. The main result is the recovery of relatively undifferentiated lithotypes that provide further insights on the magmatic spectrum existing in the Pontine Archipelago, allowing modelling of the whole suite of rocks by fractional crystallization processes. New major and trace element data and thermodynamic constrains (by the software PELE) indicate the existence of three distinct evolutionary trends corresponding to a HK calcalkaline series in the Pliocene, followed by a transitional and then by a shoshonite series in the Pleistocene. In particular, the transitional series, so far overlooked in the literature, is required in order to explain the genesis of several peralkaline felsic rocks recognized in the Archipelago. On the whole, the new geochemical data i) confirm the orogenic signature of the suites, ii) allow to rule out an anatectic origin for both subalkaline and peralkaline rhyolites and iii) indicate highly heterogeneous mantle sources, due to crustal components variously recycled in the mantle via subduction.

  9. Granite ascent in convergent orogenic belts: Testing a model

    Science.gov (United States)

    Solar, Gary S.; Pressley, Rachel A.; Brown, Michael; Tucker, Robert D.

    1998-08-01

    The common spatial relationship in convergent orogenic belts between a crustal-scale shear-zone system, high-grade metamorphic rocks, and granites suggests a feedback relation between crustal anatexis and contractional deformation that helps granite extraction and focuses granite ascent. Such a feedback relation has been proposed for ascent of Early Devonian granites in west-central Maine. This interpretation requires that deformation, metamorphism, and plutonism were synchronous. We have determined precise U-Pb zircon and monazite ages that we interpret to record time of crystallization of syntectonic granite in metric to decametric sheets and kilometric plutons, and of schlieric granite within migmatites. Ages are in the range ca. 408 404 Ma, within 1 m.y. at 95% confidence limits. These ages are similar to extant U-Pb monazite ages of ca. 405 399 ± 2 Ma for syntectonic regional metamorphism in the same area. The coincidence between the age of peak metamorphism and crystallization ages of granite shows tectonics, metamorphism, and magmatism were contemporaneous, in support of the feedback model.

  10. Submarine Landslides at Santa Catalina Island, California

    Science.gov (United States)

    Legg, M. R.; Francis, R. D.

    2011-12-01

    Santa Catalina Island is an active tectonic block of volcanic and metamorphic rocks originally exposed during middle Miocene transtension along the evolving Pacific-North America transform plate boundary. Post-Miocene transpression created the existing large pop-up structure along the major strike-slip restraining bend of the Catalina fault that forms the southwest flank of the uplift. Prominent submerged marine terraces apparent in high-resolution bathymetric maps interrupt the steep submarine slopes in the upper ~400 meters subsea depths. Steep subaerial slopes of the island are covered by Quaternary landslides, especially at the sea cliffs and in the blueschist metamorphic rocks. The submarine slopes also show numerous landslides that range in area from a few hectares to more than three sq-km (300 hectares). Three or more landslides of recent origin exist between the nearshore and first submerged terrace along the north-facing shelf of the island's West End. One of these slides occurred during September 2005 when divers observed a remarkable change in the seafloor configuration after previous dives in the area. Near a sunken yacht at about 45-ft depth where the bottom had sloped gently into deeper water, a "sinkhole" had formed that dropped steeply to 100-ft or greater depths. Some bubbling sand was observed in the shallow water areas that may be related to the landslide process. High-resolution multibeam bathymetry acquired in 2008 by CSU Monterey Bay show this "fresh" slide and at least two other slides of varying age along the West End. The slides are each roughly 2 hectares in area and their debris aprons are spread across the first terrace at about 85-m water depth that is likely associated with the Last Glacial Maximum sealevel lowstand. Larger submarine slides exist along the steep Catalina and Catalina Ridge escarpments along the southwest flank of the island platform. A prominent slide block, exceeding 3 sq-km in area, appears to have slipped more than

  11. ROV Tiburon Investigation of Hawaiian Submarine Canyons

    Science.gov (United States)

    Paull, C. K.; Greene, H. G.; Caress, D. W.; Clague, D. A.; Ussler, W.; Maher, N. M.

    2001-12-01

    MBARI conducted ROV dives around the Hawaiian Islands during an expedition of the R/V Western Flyer and Tiburon in the spring of 2001. Eight ROV dives were made to investigate five major submarine canyons offshore of Oahu, Molokai, and Hawaii in up to 3,434 m water depths. Four of these canyons are located off the windward (northern) side of these islands where onshore canyons are also well developed. Those canyons located offshore of Molokai and Oahu incise the head scars of the giant Nuuanu and Wailai submarine landslides. ROV observations and sediment and rock outcrop sampling were made in these canyons to determine their origin and present-day activity. The fifth canyon investigated is located on the leeward (southern) side of Molokai. The canyons along the windward side expose extensive stratigraphic sections that reveal the history of the islands' formation. In composite, these sections contain marine pillow basalt overlain by a substantial sequence of alternating subaerial lava flows, rounded boulder conglomerates, shallow water carbonates, and hyaloclastites that indicate coastal and marine deposition. These sequences illustrate the accretion and subsequent subsidence of the islands' flanks. These canyons also have morphologically distinct upper and lower sections. The upper reaches of the canyons are incised into the shallow water marine facies and contain broad axial channels through which active sediment transport is occurring. In contrast, the morphology of the lower canyons are strongly influenced by the giant landslides that massively altered the northern flanks of the Hawaiian chain. The lower canyons contain plunge pools and steep headwall scarps that are generally comprised of mechanically competent subaerial lava flows. The presence of multiple plunge pools with differentially eroded head scarps suggests retrogressive erosion (bottom-up process) with headward advancement of the various heads. Undercutting of the headwalls also produce periodic

  12. Relationship between work stress and health in submariners

    Directory of Open Access Journals (Sweden)

    Nan-nan JIANG

    2013-09-01

    Full Text Available Objective To explore the relationship between work stress and health in submariners. Methods In April 2008, 272 submariners trained in a navy base were selected as study subjects by random group sampling method, and tested by primary personal information questionnaire, self-rated health measurement scale (SRHMS, self-developed submariners' work stressors questionnaire, and work stress self-rated scale. Physical health, mental health and social health of submariners were analyzed, and scores were compared with the norm of reference scores. Correlations were analyzed respectively between 10 items of submariners' general information (including age, length of military service, education degree, years at the present post, times of receiving awards, on-duty hours, off-duty hours, hours of sleep, lost days of leave, positive attitude to work and their physical health score, mental health score, social health score, total health score, as well as between 15 submariners' work stressors (including workrelated risks, diet problems, high temperature, humidity and noise in workplace, shortage of clean clothes, illness, losing contact with outside, lack of information about the task, lacking supports from family members, relationship problems, lack of involvement in task decisions, boring and dull work, on duty, heavy work, high quality of work, coping with unexpected threat and their physical health score, mental health score, social health score and total health score. Results No significant difference was found between submariners' SRHMS total score and the normal referenced score (t=0.56, P>0.05, but the physical health score and mental health score were significantly lower than normal referenced scores respectively (t=–2.172, P<0.05; t=–3.299, P<0.01, and the social health score was significantly higher than normal referenced score (t=9.331, P<0.001. The age, length of military service, years at present post of submariners were related

  13. Anatexis witnessed post-collisional evolution of the Dabie orogen, China

    Science.gov (United States)

    Xu, Haijin; Zhang, Junfeng

    2017-09-01

    Crustal anatexis plays a significant role in the processes of orogenic evolution. We carried out a combined study of structure, U-Pb age and trace element on zircons from leucosome-based migmatites in the North Dabie zone to provide information on crustal anatexis during the evolution of the Dabie orogen. Protoliths of the migmatites are Middle Neoproterozoic (ca. 780-710 Ma) magmatic rocks that belong to the South China Block. They underwent a relatively low-T eclogite-facies metamorphism during the Middle to Late Triassic (235-225 Ma) continental subduction and collision. An over-thickened crustal root was formed and the Dabie orogen entered into the stage of post-collisional evolution after the Triassic. The earliest anatexis occurred at ca. 185 Ma; the anatexis in the Jurassic was weak and gentle due to episodic flow of metamorphic fluids with a prolonged interval. Nevertheless, it indicates that the crustal root started to become ductile and unstable at that time. Extensive epsodic anatexis occurred between ca. 160 Ma and 110 Ma. As the anatexis became stronger, more extensive and uninterrupted, the anatectic products changed gradually from low-degree migmatites to high-degree migmatites. The beginning of extensive anatexis at ∼160 Ma marks the beginning of orogenic activation. The duration of ca. 160-145 Ma corresponds to the orogenic activation when the collision-thickened crust still remained, whereas the period of ca. 145-110 Ma is in accordance with the orogenic collapse. The peak period of anatexis (ca. 145-125 Ma) was accompanied by plutonism, high-T granulite-facies metamorphism, extensional uplift and subsequent delamination of crustal root. After that, the anatexis trailed off until ca. 110 Ma. The long lasting multistage anatexis recorded in the migmatites has witnessed the evolution of the Dabie orogen in the postcollisional stage.

  14. Continental Growth and Recycling in Convergent Orogens with Large Turbidite Fans on Oceanic Crust

    Directory of Open Access Journals (Sweden)

    Ben D. Goscombe

    2013-07-01

    Full Text Available Convergent plate margins where large turbidite fans with slivers of oceanic basement are accreted to continents represent important sites of continental crustal growth and recycling. Crust accreted in these settings is dominated by an upper layer of recycled crustal and arc detritus (turbidites underlain by a layer of tectonically imbricated upper oceanic crust and/or thinned continental crust. When oceanic crust is converted to lower continental crust it represents a juvenile addition to the continental growth budget. This two-tiered accreted crust is often the same thickness as average continental crustal and is isostatically balanced near sea level. The Paleozoic Lachlan Orogen of eastern Australia is the archetypical example of a tubidite-dominated accretionary orogeny. The Neoproterozoic-Cambrian Damaran Orogen of SW Africa is similar to the Lachlan Orogen except that it was incorporated into Gondwana via a continent-continent collision. The Mesozoic Rangitatan Orogen of New Zealand illustrates the transition of convergent margin from a Lachlan-type to more typical accretionary wedge type orogen. The spatial and temporal variations in deformation, metamorphism, and magmatism across these orogens illustrate how large volumes of turbidite and their relict oceanic basement eventually become stable continental crust. The timing of deformation and metamorphism recorded in these rocks reflects the crustal thickening phase, whereas post-tectonic magmatism constrains the timing of chemical maturation and cratonization. Cratonization of continental crust is fostered because turbidites represent fertile sources for felsic magmatism. Recognition of similar orogens in the Proterozoic and Archean is important for the evaluation of crustal growth models, particularly for those based on detrital zircon age patterns, because crustal growth by accretion of upper oceanic crust or mafic underplating does not readily result in the addition of voluminous zircon

  15. From submarine to lacustrine groundwater discharge

    Science.gov (United States)

    Lewandowski, Jörg; Meinikmann, Karin; Pöschke, Franziska; Nützmann, Gunnar; Rosenberry, Donald O.

    2017-01-01

    Submarine groundwater discharge (SGD) and its role in marine nutrient cycling are well known since the last decade. The freshwater equivalent, lacustrine groundwater discharge (LGD), is often still disregarded, although first reports of LGD are more than 50 years old. We identify nine different reasons why groundwater has long been disregarded in both freshwater and marine environments such as invisibility of groundwater discharge, the size of the interface and its difficult accessibility. Although there are some fundamental differences in the hydrology of SGD and LGD, caused primarily by seawater recirculation that occurs only in cases of SGD, there are also a lot of similarities such as a focusing of discharge to near-shore areas. Nutrient concentrations in groundwater near the groundwater–surface water interface might be anthropogenically enriched. Due to spatial heterogeneity of aquifer characteristics and biogeochemical processes, the quantification of groundwater-borne nutrient loads is challenging. Both nitrogen and phosphorus might be mobile in near-shore aquifers and in a lot of case studies large groundwater-borne nutrient loads have been reported.

  16. Design and analysis of submarine radome

    Science.gov (United States)

    Sandeep, C. Satya; Prasad, U. Shiva; Suresh, R.; Rathan, A.; Sravanthi, G.; Govardhan, D.

    2017-07-01

    Radomes are the electromagnetic windows that protect microwave sub-systems from the environmental effects. The major requirement of radome is its transparency to microwaves and for most of the cases mechanical properties are also equally important. Radome for underwater applications has to withstand high water pressure of the order of 45 bars. Composite materials owing to their high strength to weight ratio, high stiffness and better corrosion resistance are potential source for under water applications. The concept of 'tailoring' the material properties to suit the radome is obtained by selecting proper reinforcement, resin matrix and their compositions. The mechanical properties of composite material, evaluated by testing specimens as per ASTM standards, are utilized in designing the radome. The modulus properties calculated using classical theories of composite materials and compared with test results. ANSYS a Finite Element software package used to analyse the problem. As the cross sectional thickness of radome varies, the complexity in fabrication is overcome by adopting matched die techniques. The radome design and finite element analysis validation concluded by conducting the pressure test on radome. On the design a modal analysis is also carried to check for the natural frequency, So that resonance does not occur if the natural frequency of the radome coincides with the excitation frequency of the submarine Clinical information system (CIS) for UNRWA is a computerized distributed application that used in clinics which follows the United Nations Relief and Works Agency (UNRWA) to manage the clinical requirements and services.

  17. Submarine landslides of the Southern California Borderland

    Science.gov (United States)

    Lee, H.J.; Greene, H. Gary; Edwards, B.D.; Fisher, M.A.; Normark, W.R.

    2009-01-01

    Conventional bathymetry, sidescan-sonar and seismic-reflection data, and recent, multibeam surveys of large parts of the Southern California Borderland disclose the presence of numerous submarine landslides. Most of these features are fairly small, with lateral dimensions less than ??2 km. In areas where multibeam surveys are available, only two large landslide complexes were identified on the mainland slope- Goleta slide in Santa Barbara Channel and Palos Verdes debris avalanche on the San Pedro Escarpment south of Palos Verdes Peninsula. Both of these complexes indicate repeated recurrences of catastrophic slope failure. Recurrence intervals are not well constrained but appear to be in the range of 7500 years for the Goleta slide. The most recent major activity of the Palos Verdes debris avalanche occurred roughly 7500 years ago. A small failure deposit in Santa Barbara Channel, the Gaviota mudflow, was perhaps caused by an 1812 earthquake. Most landslides in this region are probably triggered by earthquakes, although the larger failures were likely conditioned by other factors, such as oversteepening, development of shelf-edge deltas, and high fluid pressures. If a subsequent future landslide were to occur in the area of these large landslide complexes, a tsunami would probably result. Runup distances of 10 m over a 30-km-long stretch of the Santa Barbara coastline are predicted for a recurrence of the Goleta slide, and a runup of 3 m over a comparable stretch of the Los Angeles coastline is modeled for the Palos Verdes debris avalanche. ?? 2009 The Geological Society of America.

  18. Seismic reflections associated with submarine gas hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Andreassen, K.

    1995-12-31

    Gas hydrates are often suggested as a future energy resource. This doctoral thesis improves the understanding of the concentration and distribution of natural submarine gas hydrates. The presence of these hydrates are commonly inferred from strong bottom simulating reflection (BSR). To investigate the nature of BSR, this work uses seismic studies of hydrate-related BSRs at two different locations, one where gas hydrates are accepted to exist and interpreted to be very extensive (in the Beaufort Sea), the other with good velocity data and downhole logs available (offshore Oregon). To ascertain the presence of free gas under the BSR, prestack offset data must supplement near-vertical incidence seismic data. A tentative model for physical properties of sediments partially saturated with gas hydrate and free gas is presented. This model, together with drilling information and seismic data containing the BSR beneath the Oregon margin and the Beaufort Sea, made it possible to better understand when to apply the amplitude-versus-offset (AVO) method to constrain BSR gas hydrate and gas models. Distribution of natural gas hydrates offshore Norway and Svalbard is discussed and interpreted as reflections from the base of gas hydrate-bearing sediments, overlying sediments containing free gas. Gas hydrates inferred to exist at the Norwegian-Svalbard continental margin correlate well with Cenozoic depocenters, and the associated gas is assumed to be mainly biogenic. Parts of that margin have a high potential for natural gas hydrates of both biogenic and thermogenic origin. 235 refs., 86 figs., 4 tabs.

  19. Submarine landslides in Arctic sedimentation: Canada Basin

    Science.gov (United States)

    Mosher, David C.; Shimeld, John; Hutchinson, Deborah R.; Lebedova-Ivanova, N; Chapman, C.

    2016-01-01

    Canada Basin of the Arctic Ocean is the least studied ocean basin in the World. Marine seismic field programs were conducted over the past 6 years using Canadian and American icebreakers. These expeditions acquired more than 14,000 line-km of multibeam bathymetric and multi-channel seismic reflection data over abyssal plain, continental rise and slope regions of Canada Basin; areas where little or no seismic reflection data existed previously. Canada Basin is a turbidite-filled basin with flat-lying reflections correlateable over 100s of km. For the upper half of the sedimentary succession, evidence of sedimentary processes other than turbidity current deposition is rare. The Canadian Archipelago and Beaufort Sea margins host stacked mass transport deposits from which many of these turbidites appear to derive. The stratigraphic succession of the MacKenzie River fan is dominated by mass transport deposits; one such complex is in excess of 132,000 km2 in area and underlies much of the southern abyssal plain. The modern seafloor is also scarred with escarpments and mass failure deposits; evidence that submarine landsliding is an ongoing process. In its latest phase of development, Canada Basin is geomorphologically confined with stable oceanographic structure, resulting in restricted depositional/reworking processes. The sedimentary record, therefore, underscores the significance of mass-transport processes in providing sediments to oceanic abyssal plains as few other basins are able to do.

  20. Deformation of the Songshugou ophiolite in the Qinling orogen

    Science.gov (United States)

    Sun, Shengsi; Dong, Yunpeng

    2017-04-01

    The Qinling orogen, middle part of the China Central Orogenic Belt, is well documented that was constructed by multiple convergences and subsequent collisions between the North China and South China Blocks mainly based on geochemistry and geochronology of ophiolites, magmatic rocks as well as sedimentary reconstruction. However, this model is lack of constraints from deformation of subduction/collision. The Songshugou ophiolite outcropped to the north of the Shangdan suture zone represents fragments of oceanic crust and upper mantle. Previous works have revealed that the ophiolite was formed at an ocean ridge and then emplaced in the northern Qinling belt. Hence, deformation of the ophiolite would provide constraints for the rifting and subduction processes. The ophiolite consists chiefly of metamorphosed mafic and ultramafic rocks. The ultramafic rocks contain coarse dunite, dunitic mylonite and harzburgite, with minor diopsidite veins. The mafic rocks are mainly amphibolite, garnet amphibolite and amphibole schist, which are considered to be eclogite facies and retrograde metamorphosed oceanic crust. Amphibole grains in the mafic rocks exhibit a strong shape-preferred orientation parallel to the foliation, which is also parallel to the lithologic contacts between mafic and ultramafic rocks. Electron backscattered diffraction (EBSD) analyses show strong olivine crystallographic preferred orientations (CPO) in dunite including A-, B-, and C-types formed by (010)[100], (010)[001] and (100)[001] dislocation slip systems, respectively. A-type CPO suggests high temperature plastic deformation in the upper mantle. In comparison, B-type may be restricted to regions with significantly high water content and high differential stress, and C-type may also be formed in wet condition with lower differential stress. Additionally, the dunite evolved into amphibolite facies metamorphism with mineral assemblages of olivine + talc + anthophyllite. Assuming a pressure of 1.5 GPa

  1. Thermal evolution of the central Halls Creek Orogen, northern Australia

    Energy Technology Data Exchange (ETDEWEB)

    Bodorkos, S.; Cawood, P.A. [Curtin University of Technology, Perth, WA (Australia). Tectonics Special Research Centre, School of Applied Geology; Oliver, N.H.S. [James Cook University, Townsville, QLD (Australia). Economic Geology Research Unit, School of Earth Sciences

    1999-06-01

    The Halls Creek Orogen in northern Australia records the Palaeoproterozoic collision of the Kimberley Craton with the North Australian Craton. Integrated structural, metamorphic and geochronological studies of the Tickalara Metamorphics show that this involved a protracted episode of high temperature, low-pressure metamorphism associated with intense and prolonged mafic and felsic intrusive activity in the interval ca 1850-1820 Ma. Tectonothermal development of the region commenced with an inferred mantle perturbation event, probably at ca 1880 Ma. This resulted in the generation of mafic magmas in the upper mantle or lower crust, while upper crustal extension preceded the rapid deposition of the Tickalara sedimentary protoliths. An older age limit for these rocks is provided by a psammopelitic gneiss from the Tickalara Metamorphics, which yield a {sup 207}Pb/{sup 206}Pb SHRIMP age of 1867 {+-} 4 Ma for the youngest detrital zircon suite. Voluminous layered mafic intrusives were emplaced in the middle crust at ca 1860-1855 Ma. prior to the attainment of lower granulite facies peak metamorphic conditions in the middle crust. Locally preserved layer-parallel D{sub 1} foliations that were developed during prograde metamorphism were pervasively overprinted by the dominant regional S{sub 2} gneissosity coincident with peak metamorphism. Overgrowths on zircons record a metamorphic {sup 207}Pb/{sup 206}Pb age of 1845 {+-} 4 Ma. The S{sub 2} fabric is folded around tight folds and cut by ductile shear zones associated with D{sub 3} (ca 1830 Ma), and all pre-existing structures are folded around large-scale, open F{sub 4} folds (ca 1820 Ma). Construction of a temperature-time path for the mid-crustal section exposed in the central Halls Creek Orogen, based on detailed SHRIMP zircon data, key field relationships and petrological evidence, suggests the existence of one protracted thermal event (>400-500degC for 25-30 million years) encompassing two deformation phases

  2. Lithosphere profiles across Central Asian Orogenic Belt in Uzbekistan

    Science.gov (United States)

    Sidorova, Irina

    2014-05-01

    This study was made with complex geophysical and geological observations by the DSS-MRW seismic profiles, which cross CAOB in the southern Tien Shan in part of Uzbekistan. The southern Tien Shan is situated along the SW margin of the Central Asian Orogenic Belt-one of key region for understanding both the amalgamation of Eurasia and the Phanerozoic growth of the CAOB itself. The aim of our study was to reveal new features, which characteristic of the upper mantle rocks, related to morphology of bodies. their physical properties, consisting mainly in their contrasting values for contiguous blocks, and general increased velocity and density of the rocks they contain. The most interesting results were obtained by three DSS profiles in Central Kyzylkum: anomalous geological objects (Muruntau, Kokpatas, Kuldjuktau and other) having anomalous high velocity and density values, have been mapped at different depths within the part of CAOB. The alteration zones, the tectonic faults and circular structures related to the cones and calderas determined these methods and checked by group truth studies may the target areas to explore for some new deposits.New regional features have been revealed:they include peculiarities of the Earth's crust's deep geological structure and spatial distribution of deposits:they are contrast areas of the earth's crust geoblocks with anomalously high and low seismic and density parameters. Mapping of these zones helps select new ways in th search for mineral deposits. All the final products was created using ArcGIS and RS methodologies:1)DEM on the base of SRTM dataset;2) 3-D models of crustal basement and Moho surface;3) 3-D potential fields modeling;4) tabular database of tectonic, boreholes data;5)various types of original geological information concerning the Paleozoic to present geological evolution of the region.

  3. NSMRL: A Small Command with A Huge Presence for the Submarine Force

    National Research Council Canada - National Science Library

    Daniel, J. C; Lamb, Jerry

    2005-01-01

    "To protect the health and enhance the performance of our warfighters through focused submarine, diving and surface research solutions" is the mission of the Naval Submarine Medical Research Laboratory (NSMRL...

  4. Conduct and Support of Amphibious Operations from United States Submarines in World War II

    Science.gov (United States)

    2010-11-01

    twelfth war patrol of the Gato class submarine (See photos 1 and 2). They made history as the only Americans to conduct an offensive landing on a...Naval History Vol. 2, no. 1 (April 1, 2003), 1. 4 This monograph features five Gato class submarines, and three V-class submarines, but also addresses...1993), 67. 6 Photo 2: USS Barb (SS 220), representing the five Gato class submarines that participated in Operation Torch. Barb’s crew also

  5. Index of Submarine Medical Officer’s Qualification Theses 1944-1974

    Science.gov (United States)

    1976-04-01

    DEAD SPACE MEASUREMENTS BEFCRE AND 1968-3009 -- ESP IRATORY DEAD SPACE VARIAION TUDINVL---t b-0 9 INJURIES ON+ A SYLLABUS DEALING WITH THE MANAGEMENT OF...SUBARIkNE MEDICINEO A SYLLABUS OF.- SUBMARINE MEDICAL QUALIFICATION THESES U. S. NAVAL SJBMARINE MEDICAL CENTER SUBMARIN BASE, NEW LCNOOjN, GROTON...CARBON DIOXIDE ABSORBENT EVALUATION AND CANNISTER DESIGN *= SUBMARINE MDCLUALIFICATICN THESES U. -S.NAVAL SUBMARE MEDICAL CENTER SUBMARINE BASE, NEW LCNDON

  6. Taiwan strait dispute

    Directory of Open Access Journals (Sweden)

    Kastrati Bilbil

    2015-12-01

    Full Text Available The end of the Cold War resulted in a diffusion of the level of threat worldwide and concluded the system of bipolarity in the world. Beside the European continent, where the rivalries were at the highest level, the consequences of the end of the Cold War were especially visible in North-East Asia. A decrease of military activities of Russia and China, and the retreat of the USA from the region, give way for improvement of political and economical relations between the countries of the region. The end of hostilities produced by the Cold War no doubt have relaxed relations between countries in the region and opened ways for a new more peaceful co-existence. However, this does not mean that the region is not vulnerable to some of the hot spots such as North Korea, Spratly Parcels and especially Taiwan Strait. The latter is considered to be the most dangerous potential Asian zone of crisis in the twenty-first century.

  7. Enterovirus 71 in Taiwan

    Directory of Open Access Journals (Sweden)

    Luan-Yin Chang

    2008-08-01

    Full Text Available The enterovirus 71 (EV71 outbreak in Taiwan in 1998 proved fatal in many children. A seroepidemiological study performed prior to the 1998 outbreak showed pre-epidemic (1997 EV71 seroprevalence rates to be about 60–70% in adults and children older than 6 years of age. A retrospective case review carried out from 1980–81 identified 16 cases of hand, foot and mouth disease associated with central nervous system involvement, two of whom died soon after hospitalization. There were 405 severe cases and 78 deaths reported in the 1998 epidemic, and dozens of fatal EV71 cases were still reported from 2000 to 2002. A stage-based management strategy was developed to reduce fatality, but most survivors of brainstem encephalitis with cardio pulmonary failure have neurologic sequelae and impaired cognition. Continuous clinical and laboratory surveillance of EV71 disease is required to enable earlier implementation of control and prevention measures. Development of EV71-specific antiviral therapy, a novel class of imidazolidinones, and development of a vaccine are ongoing.

  8. Taiwan's second remote sensing satellite

    Science.gov (United States)

    Chern, Jeng-Shing; Ling, Jer; Weng, Shui-Lin

    2008-12-01

    FORMOSAT-2 is Taiwan's first remote sensing satellite (RSS). It was launched on 20 May 2004 with five-year mission life and a very unique mission orbit at 891 km altitude. This orbit gives FORMOSAT-2 the daily revisit feature and the capability of imaging the Arctic and Antarctic regions due to the high enough altitude. For more than three years, FORMOSAT-2 has performed outstanding jobs and its global effectiveness is evidenced in many fields such as public education in Taiwan, Earth science and ecological niche research, preservation of the world heritages, contribution to the International Charter: space and major disasters, observation of suspected North Korea and Iranian nuclear facilities, and scientific observation of the atmospheric transient luminous events (TLEs). In order to continue the provision of earth observation images from space, the National Space Organization (NSPO) of Taiwan started to work on the second RSS from 2005. This second RSS will also be Taiwan's first indigenous satellite. Both the bus platform and remote sensing instrument (RSI) shall be designed and manufactured by NSPO and the Instrument Technology Research Center (ITRC) under the supervision of the National Applied Research Laboratories (NARL). Its onboard computer (OBC) shall use Taiwan's indigenous LEON-3 central processing unit (CPU). In order to achieve cost effective design, the commercial off the shelf (COTS) components shall be widely used. NSPO shall impose the up-screening/qualification and validation/verification processes to ensure their normal functions for proper operations in the severe space environments.

  9. Taiwan Universities: Where to Go?

    Directory of Open Access Journals (Sweden)

    Yu-Ying Kuo

    2016-02-01

    Full Text Available The dramatic expansion of Taiwan universities/colleges from about 100 to 160 from the late 1980s has encountered problems due to social and global changes. What should Taiwan universities move toward and how? This research relies on secondary data to explore the issues Taiwan universities currently face—a low birth rate and global competition. The decreasing number of incoming students will result in a lower registration rate and less tuition revenue, which will make some universities struggle to survive. Hence, government policies, proposed by the Ministry of Education, have been implemented to assist Taiwan universities to adjust to external changes. The Innovative Transformation Policy, adopted in 2015, consists of strategies for university–industry cooperation, university mergers, university closures, and a re-shaping of the university paradigm. This policy has begun to be implemented and its initial outcome will be continually evaluated. In accordance with the Innovative Transformation Policy, this study encourages Taiwan universities to improve governance, set prominent unique characteristics of development, and enhance global competitiveness.

  10. Professional Counseling in Taiwan: Past to Future

    Science.gov (United States)

    Guo, Yuh-Jen; Wang, Shu-Ching; Combs, Don C.; Lin, Yi-Chun; Johnson, Veronica

    2013-01-01

    Because of the recent introduction of a licensure law, professional counseling has grown rapidly in Taiwan after decades of slow development. The authors provide a historical review of the development of professional counseling in Taiwan and discuss the current status and future trajectory of professional counseling in Taiwan.

  11. Navy Ohio Replacement (SSBN[X]) Ballistic Missile Submarine Program: Background and Issues for Congress

    Science.gov (United States)

    2016-04-05

    Navy Ohio Replacement (SSBN[X]) Ballistic Missile Submarine Program: Background and Issues for Congress Ronald O’Rourke Specialist in Naval...Affairs April 5, 2016 Congressional Research Service 7-5700 www.crs.gov R41129 Navy Ohio Replacement (SSBN[X]) Ballistic Missile Submarine...Replacement (SSBN[X]) Ballistic Missile Submarine Program Congressional Research Service Contents Introduction

  12. Submarine fans: A critical retrospective (1950–2015

    Directory of Open Access Journals (Sweden)

    G. Shanmugam

    2016-04-01

    Full Text Available When we look back the contributions on submarine fans during the past 65 years (1950–2015, the empirical data on 21 modern submarine fans and 10 ancient deep-water systems, published by the results of the First COMFAN (Committee on FANs Meeting (Bouma et al., 1985a, have remained the single most significant compilation of data on submarine fans. The 1970s were the “heyday” of submarine fan models. In the 21st century, the general focus has shifted from submarine fans to submarine mass movements, internal waves and tides, and contourites. The purpose of this review is to illustrate the complexity of issues surrounding the origin and classification of submarine fans. The principal elements of submarine fans, composed of canyons, channels, and lobes, are discussed using nine modern case studies from the Mediterranean Sea, the Equatorial Atlantic, the Gulf of Mexico, the North Pacific, the NE Indian Ocean (Bay of Bengal, and the East Sea (Korea. The Annot Sandstone (Eocene–Oligocene, exposed at Peira-Cava area, SE France, which served as the type locality for the “Bouma Sequence”, was reexamined. The field details are documented in questioning the validity of the model, which was the basis for the turbidite-fan link. The 29 fan-related models that are of conceptual significance, developed during the period 1970–2015, are discussed using modern and ancient systems. They are: (1 the classic submarine fan model with attached lobes, (2 the detached-lobe model, (3 the channel-levee complex without lobes, (4 the delta-fed ramp model, (5 the gully-lobe model, (6 the suprafan lobe model, (7 the depositional lobe model, (8 the fan lobe model, (9 the ponded lobe model, (10 the nine models based on grain size and sediment source, (11 the four fan models based on tectonic settings, (12 the Jackfork debrite model, (13 the basin-floor fan model, (14 supercritical and subcritical fans, and (15 the three types of fan reservoirs. Each model is unique

  13. Process sedimentology of submarine fan deposits - new perspectives

    Science.gov (United States)

    Postma, George

    2017-04-01

    To link submarine fan process sedimentology with sand distribution, sand body architecture, texture and fabric, the field geologist studies sedimentary facies, facies associations (fan elements) and stratigraphy. Facies analysis resides on factual knowledge of modern fan morphodynamics and physical modelling of en-masse sediment transport. Where do we stand after 55 years of submarine research, i.e. the date when the first submarine fan model was launched by Arnold Bouma in 1962? Since that date students of submarine fans have worked on a number of important, recurring questions concerned with facies analysis of submarine successions in outcrop and core: 1. What type of sediment transport produced the beds? 2. What facies can be related to initial flow conditions? 3. What is the significance of grain size jumps and bounding surface hierarchy in beds consisting of crude and spaced stratification (traction carpets)? Do these point to multi flow events or to flow pulsations by one and the same event? 4. What facies associations relate to the basic elements of submarine fans? 5. What are the autogenic and allogenic signatures in submarine fans? Particularly in the last decade, the enormous technical advancement helped to obtain high-quality data from observations of density flows in modern canyons, deep basins and deep-water delta slopes (refs 1,2,3). In combination with both physical (refs 4,5) and numerical modelling (ref 6) these studies broke new ground into our understanding of density flow processes in various submarine environments and have led to new concepts of submarine fan building by super- and subcritical high-density flow (ref 7). Do these new concepts provide better answers to our recurrent questions related to the morphodynamics of submarine fans and prediction of sand body architecture? In discussing this open question, I shall 1. apply the new concepts to a modern and ancient example of a channel-lobe-transition-zone (ref 8); 2. raise the problem of

  14. The giant Jiaodong gold province: The key to a unified model for orogenic gold deposits?

    Directory of Open Access Journals (Sweden)

    David I. Groves

    2016-05-01

    Full Text Available Although the term orogenic gold deposit has been widely accepted for all gold-only lode-gold deposits, with the exception of Carlin-type deposits and rare intrusion-related gold systems, there has been continuing debate on their genesis. Early syngenetic models and hydrothermal models dominated by meteoric fluids are now clearly unacceptable. Magmatic-hydrothermal models fail to explain the genesis of orogenic gold deposits because of the lack of consistent spatially – associated granitic intrusions and inconsistent temporal relationships. The most plausible, and widely accepted, models involve metamorphic fluids, but the source of these fluids is hotly debated. Sources within deeper segments of the supracrustal successions hosting the deposits, the underlying continental crust, and subducted oceanic lithosphere and its overlying sediment wedge all have their proponents. The orogenic gold deposits of the giant Jiaodong gold province of China, in the delaminated North China Craton, contain ca. 120 Ma gold deposits in Precambrian crust that was metamorphosed over 2000 million years prior to gold mineralization. The only realistic source of fluid and gold is a subducted oceanic slab with its overlying sulfide-rich sedimentary package, or the associated mantle wedge. This could be viewed as an exception to a general metamorphic model where orogenic gold has been derived during greenschist- to amphibolite-facies metamorphism of supracrustal rocks: basaltic rocks in the Precambrian and sedimentary rocks in the Phanerozoic. Alternatively, if a holistic view is taken, Jiaodong can be considered the key orogenic gold province for a unified model in which gold is derived from late-orogenic metamorphic devolatilization of stalled subduction slabs and oceanic sediments throughout Earth history. The latter model satisfies all geological, geochronological, isotopic and geochemical constraints but the precise mechanisms of auriferous fluid release, like many

  15. Brittle tectonic history document the late- to post-orogenic evolution in the Lufilian Arc, RDCongo

    Science.gov (United States)

    Kipata, Louis; Delvaux, Damien; Ntabwoba Sebagenzi, Mwene; Cailteux, Jean-Jacques; Sintubin, Manuel

    2013-04-01

    Pan-African orogenic processes in Centra Africa involve intracontinental collision but also late-orogenic and intraplate processes that occurred in dominantly brittle conditions and can be documented by fault kinematic analysis and paleostress reconstructions. The Congo and Tanzania cratons in Central Africa are surrounded by Pan-African belts orogenic belts which all entered almost synchronously in collision stage in the early Paleozoic. While their tectonic history up to the collision stage is increasingly better documented by ductile deformation and metamorphic studies, their late evolution remain poorly known as soon as they enter in the brittle deformation regime. This results in an incomplete understanding of the orogenic processes, especially when the transition from ductile to the brittle regime occurred at the end of the orogenic compression. In this case, the last compressional stages and the entire late orogenic extension and extensional collapse stages remain undocumented. This is the case for the Lufilian orogeny which developed along the southern margin of the Congo Craton in Central Africa during the pan-African and was marked by a collisional event with crustal thickening and white schist formation at 550-530 Ma. The Lufilian Arc which forms the external part of the Lufilian orogeny developed as an arcuate fold-and-thrust belt. Its foreland is formed by the Kundelungu plateau, between the Bangweulu block and the Kibaran belt. This entire region is also tectonically active, as part of the incipient SW branch of the East African rift system. The long period between the paroxysm of the Lufilian orogeny and the late Neogene to Quaternary rifting has been investigated by fault-kinematic analysis and paleostress reconstruction in open mines spread over the entire arc and foreland. Paleostress tensors were computed from 23 sites totaling 1900 fault-slip data by interactive stress tensor inversion and data subset separation, and a succession of 8 brittle

  16. Early-Middle Triassic high Sr/Y granitoids in the southern Central Asian Orogenic Belt: Implications for ocean closure in accretionary orogens

    Science.gov (United States)

    Li, Shan; Chung, Sun-Lin; Wilde, Simon A.; Jahn, Bor-Ming; Xiao, Wen-Jiao; Wang, Tao; Guo, Qian-Qian

    2017-03-01

    The key to defining the termination of accretion in an accretionary orogen is to recognize the initial magmatic processes that are generated at the time of ocean closure. We present new age, geochemical, and isotopic data for magmatic rocks related to terminal collision along the Solonker-Xar Moron suture zone in the southern Central Asian Orogenic Belt (CAOB) that record such processes following closure of the Paleo-Asian Ocean. These magmatic rocks were emplaced in the Early-Middle Triassic (251-245 Ma) and show high Sr/Y signatures. Their low MgO, Cr, and Ni contents and variable whole-rock ɛNd(t) values (+5.8 to -5.3), together with the range in zircon ɛHf(t) (+15.6 to -9.8) and δ18O values (5.1 to 7.9‰), indicate an origin from partial melting of juvenile lower crustal rocks with some old components, including supracrustal recycling under garnet amphibolite facies conditions. Our data, along with available geological and geophysical evidence, lead us to propose a model of final oceanic contraction in the southern CAOB, resulting in sublinear distribution of high Sr/Y melts along the resultant collision zone, thus defining the onset of postaccretionary processes in the southern CAOB. The identification of collision-related high Sr/Y granitoids from the southern CAOB not only reveals the magmatic process in response to the final episode of orogenic evolution in the CAOB accretionary collision zone but also constrains how and when an archipelago-type accretionary orogen is terminated.

  17. Paleo-environments of Late Pliocene to Early Pleistocene Foreland-Basin Deposits in the Western Foothills of South-Central Taiwan

    Science.gov (United States)

    Chiu, Tzu-Hsuan; Tien-Shun Lin, Andrew; Chi, Wen-Rong; Wang, Shih-Wei

    2017-04-01

    Lithofacies and paleo-environmental analyses of the Pliocene-Pleistocene deposits of Taiwan provide a framework to understand the stratigraphic development of foreland basin to the west of the orogenic belt. In this study, we performed lithofacies analyses and biostratigraphic studies on calcareous nannofossils in two areas in south-central Taiwan, the Jhuoshuei River, and the Hushan Reservoir, respectively. The studied lithostratigraphic units are the Chinshui Shale, the Cholan Formation, and the Toukoshan Formation, in an ascending order, with a total stratigraphic thickness more than 3500 m in central Taiwan. Sixteen lithofacies and four lithofacies associations are identified, pertaining to tide-dominated deltaic systems bordering a shallow marine setting in the foreland basin. A few wide-spread layers of thickly-bedded sandstones featuring ball-and-pillow structures are interpreted as resulting from earthquake shaking (i.e., seismites). In addition, the vertical facies change shows a coarsening and shallowing-upward succession, indicating the gradually filling up of the foreland basin by sediment progradation. The progradation is interpreted to result from westward migrating orogenic belt and an increase in sediment supply. The top 2000-m thick foreland succession (i.e., the uppermost part of the Cholan Formation, and the Toukoshan Formation) is dominantly fluvial deposits with occasional intercalations of shoreface sediments, indicating an extremely rapid and balanced rate of basin subsidence and sediment supply for the past 1.5 Ma. Vertebrate fossils of deer and elephants are identified in the upper Cholan Formation deposited in coastal to fluvial settings. Keywords: Pliocene-Pleistocene Epoch, lithofacies, foreland basin, Taiwan

  18. A submarine volcanic eruption leads to a novel microbial habitat.

    Science.gov (United States)

    Danovaro, Roberto; Canals, Miquel; Tangherlini, Michael; Dell'Anno, Antonio; Gambi, Cristina; Lastras, Galderic; Amblas, David; Sanchez-Vidal, Anna; Frigola, Jaime; Calafat, Antoni M; Pedrosa-Pàmies, Rut; Rivera, Jesus; Rayo, Xavier; Corinaldesi, Cinzia

    2017-04-24

    Submarine volcanic eruptions are major catastrophic events that allow investigation of the colonization mechanisms of newly formed seabed. We explored the seafloor after the eruption of the Tagoro submarine volcano off El Hierro Island, Canary Archipelago. Near the summit of the volcanic cone, at about 130 m depth, we found massive mats of long, white filaments that we named Venus's hair. Microscopic and molecular analyses revealed that these filaments are made of bacterial trichomes enveloped within a sheath and colonized by epibiotic bacteria. Metagenomic analyses of the filaments identified a new genus and species of the order Thiotrichales, Thiolava veneris. Venus's hair shows an unprecedented array of metabolic pathways, spanning from the exploitation of organic and inorganic carbon released by volcanic degassing to the uptake of sulfur and nitrogen compounds. This unique metabolic plasticity provides key competitive advantages for the colonization of the new habitat created by the submarine eruption. A specialized and highly diverse food web thrives on the complex three-dimensional habitat formed by these microorganisms, providing evidence that Venus's hair can drive the restart of biological systems after submarine volcanic eruptions.

  19. Does calving matter? Evidence for significant submarine melt

    Science.gov (United States)

    Bartholomaus, Timothy C.; Larsen, Christopher F.; O’Neel, Shad

    2013-01-01

    During the summer in the northeast Pacific Ocean, the Alaska Coastal Current sweeps water with temperatures in excess of 12 °C past the mouths of glacierized fjords and bays. The extent to which these warm waters affect the mass balance of Alaskan tidewater glaciers is uncertain. Here we report hydrographic measurements made within Icy Bay, Alaska, and calculate rates of submarine melt at Yahtse Glacier, a tidewater glacier terminating in Icy Bay. We find strongly stratified water properties consistent with estuarine circulation and evidence that warm Gulf of Alaska water reaches the head of 40 km-long Icy Bay, largely unaltered. A 10–20 m layer of cold, fresh, glacially-modified water overlies warm, saline water. The saline water is observed to reach up to 10.4 °C within 1.5 km of the terminus of Yahtse Glacier. By quantifying the heat and salt deficit within the glacially-modified water, we place bounds on the rate of submarine melt. The submarine melt rate is estimated at >9 m d−1, at least half the rate at which ice flows into the terminus region, and can plausibly account for all of the submarine terminus mass loss. Our measurements suggest that summer and fall subaerial calving is a direct response to thermal undercutting of the terminus, further demonstrating the critical role of the ocean in modulating tidewater glacier dynamics.

  20. Submarine Construction in Germany (U-Bootbau in Deutschland),

    Science.gov (United States)

    1983-04-25

    the IKL sister firm, Maschinenbau Gabler GmbH, also founded by Prof. Gabler, which, unlike IKL (involved solely in development), is a hardware...snorkels, radar masts, as well as wharf and dockside connections, for IKL and various submarine yards. Moreover, Maschinenbau Gabler is engaged in

  1. Dissolved Nutrients from Submarine Groundwater in Flic en Flac ...

    African Journals Online (AJOL)

    Abstract—The aim of this study was to investigate dissolved nutrients in a submarine groundwater discharge (SGD) in Flic en Flac lagoon on the west coast of the volcanic island of Mauritius. The SGD enters Flic en Flac lagoon through a thin blanket of unconsolidated sediment through a fracture system and is concentrated ...

  2. Dissolved Nutrients from Submarine Groundwater in Flic en Flac ...

    African Journals Online (AJOL)

    The aim of this study was to investigate dissolved nutrients in a submarine groundwater discharge (SGD) in Flic en Flac lagoon on the west coast of the volcanic island of Mauritius. The SGD enters Flic en Flac lagoon through a thin blanket of unconsolidated sediment through a fracture system and is concentrated along the ...

  3. Simulation of Wave-Plus-Current Scour beneath Submarine Pipelines

    DEFF Research Database (Denmark)

    Eltard-Larsen, Bjarke; Fuhrman, David R.; Sumer, B. Mutlu

    2016-01-01

    A fully coupled hydrodynamic and morphologic numerical model was utilized for the simulation of wave-plus-current scour beneath submarine pipelines. The model was based on incompressible Reynolds-averaged Navier–Stokes equations, coupled with k-ω turbulence closure, with additional bed and suspen...

  4. Sedimentary characteristics of samples collected from some submarine canyons

    NARCIS (Netherlands)

    Bouma, Arnold H.

    Oriented rectangular cores of 20.3 × 30.5 cm and 45.7 cm high have been collected in a number of submarine canyons off southern California (U.S.A.) and off the southern tip of Baja California (Mexico) for a detailed study of their sedimentary structures. By applying several methods, mainly X-ray

  5. 'Good Hunting': German submarine offensives and South African ...

    African Journals Online (AJOL)

    The first German submarine offensive in South African waters during 1942, Operation Eisbär, was aimed at striking a devastating blow to shipping off the South African coast. By the end of December 1942, an estimated 310 864 tons of shipping had been sunk through Operation Eisbär and the first U-cruiser operation alone.

  6. Cost Estimation Lessons Learned for Future Submarine Acquisition Programs

    Science.gov (United States)

    2010-02-17

    North Carolina and New Mexico 30 General Dynamics Electric Boat “U.S. Navy Awards General Dynamics $14 Billion Contract for Eight Virginia- Class...NAVSEA Program Executive officer, Submarines PMO 450, June 1995. “New SSN Program Life Cycle Cost Estimate.” Naval Center for Cost Analysis: GE-1300

  7. Continental Collision Structures and Post-Orogenic Geological History of the Kangerlussuaq Area in the Southern Part of the Nagssugtoqidian Orogen, Central West Greenland

    Directory of Open Access Journals (Sweden)

    Jon Engström

    2014-12-01

    Full Text Available Deep-seated continental collision sutures, formed at a depth of more than 20 km, are exposed near Kangerlussuaq, close to the Greenland ice cap, on the southern margin of the Nagssugtoqidian orogen in Central West Greenland, thus offering a rare opportunity to study the tectonic deformation style of such an orogen. This paper adds new information on the tectonic history of the southern flank of the Nagssugtoqidian orogen. It focuses on (1 the results of a detailed structural investigation of lineament zones revealed from remote sensing of geophysical and topographic data and aerial photo interpretation, (2 detailed geological mapping at key locations and (3 a tectonic structural model describing the geological development of the area. The area has undergone several episodes of deformation, which have been compiled into an event succession that recognizes eight tectonic events overprinting each other: Two stages of folding (F1 and F2 have been identified along with one major episode of intrusion of the Kangâmiut mafic dyke swarm (2.05 Ga into the Archaean continent. These dyke intrusions are very important, since by examining the style of deformation for these intrusions it is possible to define the transition from the North Atlantic Craton in the south to the mobile belts in the Nagssugtoqidian orogen in the north. Five different types of pronounced lineaments and one less pronounced lineament post-dating the Kangâmiut dykes extending from ductile deformation shearing events to brittle deformation with extensive faulting. These lineaments cover both the collisional and post-collisional tectonic history of the area. The study focused on two types of lineaments: one semi-ductile type trending E–W with a dextral sense of shear and a second, a pronounced lineament outlining the Kangerlussuaq–Russell thrust fault. These two features are interpreted to be related to the Nagssugtoqidian orogeny, while the latter lineaments have a more brittle

  8. An ongoing large submarine landslide at the Japan trench

    Science.gov (United States)

    Nitta, S.; Kasaya, T.; Miura, S.; Kawamura, K.

    2013-12-01

    This paper deals with an active submarine landslide on a landward trench slope in the Japan trench. Studied area is located on the upper terrace ranging from 400 to 1200 m in water depth, off Sendai, northeast Japan. We have surveyed in detail the seabed topography using a multi narrow beam (hereafter MBES) and a subbottom profiler (hereafter SBP) during the cruise MR12-E02 of R/V Mirai. The survey lines were 12 lines in N-S, and 3 lines in E-W, and situated in the region from 141°45'E, 37°40'N to 142°33'E, 38°32'N. Moreover, we used multi-channel seismic profile by the cruise KR04-10 of R/V Kairei in the interpretation of the SBP results. In general, horseshoe-shaped depressions of about 100 km wide along the trench slope are arrayed along the Japan trench. It has thought that they were formed by large submarine landslides, but we could not understand critically the relationship between the depressions and the submarine landslides. Based on the survey results, we found signals of an active submarine landslide in the depression as follows. 1) We observed arcuate-shaped lineaments, which are sub-parallel to a horseshoe-shaped depression. The lineaments concentrate in the south region from 38°N at about 20 km wide. These lineaments are formed by deformation structures as anticlines, synclines and normal fault sense displacements. 2) Most of the synclines and anticlines are not buried to form the lineaments. 3) Normal faults cutting about 1 km deep are observed in a multi-channel seismic profile. The normal faults are located just below the arcuate-shaped lineaments, and are tilted eastward being the downslope direction. It indicates a large submarine landslide. We concluded that the arcuate-shaped lineaments were generated by surface sediment movement with the submarine landsliding. We think that the submarine landslide of about 20 km wide and about 1 km thick move continuously down the landward trench slope. This would be the formation process of the horseshoe

  9. Orogen-parallel deformation of the Himalayan midcrust: Insights from structural and magnetic fabric analyses of the Greater Himalayan Sequence, Annapurna-Dhaulagiri Himalaya, central Nepal

    Science.gov (United States)

    Parsons, A. J.; Ferré, E. C.; Law, R. D.; Lloyd, G. E.; Phillips, R. J.; Searle, M. P.

    2016-11-01

    The metamorphic core of the Himalaya (Greater Himalayan Sequence, GHS), in the Annapurna-Dhaulagiri region, central Nepal, recorded orogen-parallel stretching during midcrustal evolution. Anisotropy of magnetic susceptibility and field-based structural analyses suggest that midcrustal deformation of the amphibolite facies core of the GHS occurred under an oblate/suboblate strain regime with associated formation of low-angle northward dipping foliation. Magnetic and mineral stretching lineations lying within this foliation from the top of the GHS record right-lateral orogen-parallel stretching. We propose that oblate strain within a midcrustal flow accommodated oblique convergence between India and the arcuate orogenic front without the need for strain partitioning in the upper crust. Oblate flattening may have also promoted orogen-parallel melt migration and development of melt-depleted regions between km3 scale leucogranite culminations at 50-100 km intervals along orogen strike. Following the cessation of flow, continued oblique convergence led to upper crustal strain partitioning between orogen-perpendicular convergence on thrust faults and orogen-parallel extension on normal and strike-slip faults. In the Annapurna-Dhaulagiri Himalaya, orogen-parallel stretching lineations are interpreted as a record of transition from midcrustal orogen-perpendicular extrusion to upper crustal orogen-parallel stretching. Our findings suggest that midcrustal flow and upper crustal extension could not be maintained simultaneously and support other studies from across the Himalaya, which propose an orogen-wide transition from midcrustal orogen-perpendicular extrusion to upper crustal orogen-parallel extension during the mid-Miocene. The 3-D nature of oblate strain and orogen-parallel stretching cannot be replicated by 2-D numerical simulations of the Himalayan orogen.

  10. An isotopic perspective on growth and differentiation of Proterozoic orogenic crust: From subduction magmatism to cratonization

    Science.gov (United States)

    Johnson, Simon P.; Korhonen, Fawna J.; Kirkland, Christopher L.; Cliff, John B.; Belousova, Elena A.; Sheppard, Stephen

    2017-01-01

    The in situ chemical differentiation of continental crust ultimately leads to the long-term stability of the continents. This process, more commonly known as 'cratonization', is driven by deep crustal melting with the transfer of those melts to shallower regions resulting in a strongly chemically stratified crust, with a refractory, dehydrated lower portion overlain by a complementary enriched upper portion. Since the lower to mid portions of continental crust are rarely exposed, investigation of the cratonization process must be through indirect methods. In this study we use in situ Hf and O isotope compositions of both magmatic and inherited zircons from several felsic magmatic suites in the Capricorn Orogen of Western Australia to highlight the differentiation history (i.e. cratonization) of this portion of late Archean to Proterozoic orogenic crust. The Capricorn Orogen shows a distinct tectonomagmatic history that evolves from an active continental margin through to intracratonic reworking, ultimately leading to thermally stable crust that responds similarly to the bounding Archean Pilbara and Yilgarn Cratons. The majority of magmatic zircons from the main magmatic cycles have Hf isotopic compositions that are generally more evolved than CHUR, forming vertical arrays that extend to moderately radiogenic compositions. Complimentary O isotope data, also show a significant variation in composition. However, combined, these data define not only the source components from which the magmas were derived, but also a range of physio-chemical processes that operated during magma transport and emplacement. These data also identify a previously unknown crustal reservoir in the Capricorn Orogen.

  11. Svecofennian intra-orogenic gabbroic magmatism: a case study from Turku, southwestern Finland

    Directory of Open Access Journals (Sweden)

    Nevalainen, J.

    2014-12-01

    Full Text Available Using single-grain zircon U-Pb dating by LA-MC-ICPMS and whole-rock geochemistry, we have studied the Palaeoproterozoic gabbroic rocks from Moisio in southwest Finland. Three ages were obtained. The interpreted intrusion age is ~1.86 Ga, which places it in the 1.87–1.84 Ga intra-orogenic period of southern Svecofennia. The other ages, ~1.89 Ga and ~1.83 Ga, are inferred to be inherited and metamorphic ages, respectively. The K, LREE, LILE, Fe-, P-, Ti- and F-concentrations reveal two compositionally distinct groups: (i an enriched monzogabbro group and (ii a less enriched gabbro group. The composition of the monzogabbro group resembles the other intra-orogenic intrusions from southern Svecofennia, whereas the unrelated gabbro group is more comparable to the synorogenic rocks in the region. The magma source the monzogabbro experienced a subduction related carbonate metasomatism, induced by sediment subduction and subduction erosion. Evidently, the Moisio monzogabbro represent enriched, mantle derived magmatism in southern Svecofennia as a part of the intra-orogenic igneous activity. The intra-orogenic magmatism is considered to have conveyed considerable amounts of heat from the mantle into the crust contributing to subsequent lateorogenic high-grade metamorphism.

  12. Rainfall variability in the Himalayan orogen and its relevance to erosion processes

    Science.gov (United States)

    Deal, Eric; Favre, Anne-Catherine; Braun, Jean

    2017-05-01

    Rainfall is an important driver of erosion processes. The mean rainfall rate is often used to account for the erosive impact of a particular climate. However, for some erosion processes, erosion rate is a nonlinear function of rainfall, e.g., due to a threshold for erosion. When this is the case, it is important to take into account the full distribution of rainfall, instead of just the mean. In light of this, we have characterized the variability of daily rainfall over the Himalayan orogen using high spatial and temporal resolution rainfall data sets. We find significant variations in rainfall variability over the Himalayan orogen, with increasing rainfall variability to the west and north of the orogen. By taking into account variability of rainfall in addition to mean rainfall rate, we find a pattern of rainfall that, from a geomorphological perspective, is significantly different from mean rainfall rate alone. Using these findings, we argue that short-term rainfall variability may help explain observed short and long-term erosion rates in the Himalayan orogen.

  13. Post-collisional magmatism in the central East African Orogen: The Maevarano Suite of north Madagascar

    Science.gov (United States)

    Goodenough, K.M.; Thomas, Ronald J.; De Waele, B.; Key, R.M.; Schofield, D.I.; Bauer, W.; Tucker, R.D.; Rafahatelo, J.-M.; Rabarimanana, M.; Ralison, A.V.; Randriamananjara, T.

    2010-01-01

    Late tectonic, post-collisional granite suites are a feature of many parts of the Late Neoproterozoic to Cambrian East African Orogen (EAO), where they are generally attributed to late extensional collapse of the orogen, accompanied by high heat flow and asthenospheric uprise. The Maevarano Suite comprises voluminous plutons which were emplaced in some of the tectonostratigraphic terranes of northern Madagascar, in the central part of the EAO, following collision and assembly during a major orogeny at ca. 550 Ma. The suite comprises three main magmatic phases: a minor early phase of foliated gabbros, quartz diorites, and granodiorites; a main phase of large batholiths of porphyritic granitoids and charnockites; and a late phase of small-scale plutons and sheets of monzonite, syenite, leucogranite and microgranite. The main phase intrusions tend to be massive, but with variably foliated margins. New U-Pb SHRIMP zircon data show that the whole suite was emplaced between ca. 537 and 522 Ma. Geochemically, all the rocks of the suite are enriched in the LILE, especially K, and the LREE, but are relatively depleted in Nb, Ta and the HREE. These characteristics are typical of post-collisional granitoids in the EAO and many other orogenic belts. It is proposed that the Maevarano Suite magmas were derived by melting of sub-continental lithospheric mantle that had been enriched in the LILE during earlier subduction events. The melting occurred during lithospheric delamination, which was associated with extensional collapse of the East African Orogen. ?? 2009 Natural Environment Research Council.

  14. Carbonatitic metasomatism in orogenic dunites from Lijiatun in the Sulu UHP terrane, eastern China

    Science.gov (United States)

    Su, Bin; Chen, Yi; Guo, Shun; Chu, Zhu-Yin; Liu, Jing-Bo; Gao, Yi-Jie

    2016-10-01

    Among orogenic peridotites, dunites suffer the weakest crustal metasomatism at the slab-mantle interface and are the best lithology to trace the origins of orogenic peridotites and their initial geodynamic processes. Petrological and geochemical investigations of the Lijiatun dunites from the Sulu ultrahigh-pressure (UHP) terrane indicate a complex petrogenetic history involving melt extraction and multistage metasomatism (carbonatitic melt and slab-derived fluid). The Lijiatun dunites consist mainly of olivine (Fo = 92.0-92.6, Ca = 42-115 ppm), porphyroblastic orthopyroxene (En = 91.8-92.8), Cr-spinel (Cr# = 50.4-73.0, TiO2 modeling, carbonatitic metasomatism had occurred within the shallow SCLM (low-P and high-T conditions) before dunites were incorporated into the continental subduction channel. These dunites then suffered weak metasomatism by slab-derived fluids, forming pargasitic amphibole after pyroxene. This work indicates that modification of the SCLM beneath the eastern margin of the NCC had already taken place before the Triassic continental subduction. Orogenic peridotites derived from such a lithospheric mantle wedge may be heterogeneously modified prior to their incorporation into the subduction channel, which would set up a barrier for investigation of the mass transfer from the subducted crust to the mantle wedge through orogenic peridotites.

  15. Magnetotelluric Study of the Southern Margin of the Capricorn Orogen, Western Australia

    Science.gov (United States)

    Piña-Varas, P.; Dentith, M. C.

    2015-12-01

    We present the current status and the preliminary results of a magnetotelluric (MT) study that is being performed in the Capricorn Orogen, in northern Western Australia. This project is a component of large multi-disciplinary geoscience project on the 'Distal Footprints of Giant Ore Systems'. The Capricorn Orogen, a largely Proterozoic orogenic belt, is being used as a natural laboratory to develop methods for exploring for mineral deposits 'under cover'. The MT dataset consists of a total of 240 broadband magnetotelluric stations (BBMT) and 84 long period stations (LMT). Analysis of the dataset reveals the area to have complex 3-D variations in electrical conductivity, making 3-D interpretation methods essential. The first 3-D inversion model encompasses south-eastern part of the Capricorn Orogen (Padbury-Bryah Basins) and the adjoining Yilgarn Craton, and involves the inversion of 58 BBMT sites. The results shown a prominent resistive feature that is tentatively correlated with the northern boundary of the Yilgarn Craton. Apart from this, the other main geoelectrical feature is a high conductivity body located within the Yilgarn Craton. This structure could be related to tectonic features associated with the accretion of the different terranes composing this part of the craton. Forward models were used to validate these and other structures. Major faults occurring at cratonic margins are known to be important indicators of increased prospectivity and our preliminary results suggest MT surveys are a useful tool for regional scale exploration in the study area.

  16. Exploring the submarine Graham Bank in the Sicily Channel

    Directory of Open Access Journals (Sweden)

    Mauro Coltelli

    2016-05-01

    Full Text Available In the Sicily Channel, volcanic activity has been concentrated mainly on the Pantelleria and Linosa islands, while minor submarine volcanism took place in the Adventure, Graham and Nameless banks. The volcanic activity spanned mostly during Plio-Pleistocene, however, historical submarine eruptions occurred in 1831 on the Graham Bank and in 1891 offshore Pantelleria Island. On the Graham Bank, 25 miles SW of Sciacca, the 1831 eruption formed the short-lived Ferdinandea Island that represents the only Italian volcano active in historical times currently almost completely unknown and not yet monitored. Moreover, most of the Sicily Channel seismicity is concentrated along a broad NS belt extending from the Graham Bank to Lampedusa Island. In 2012, the Istituto Nazionale di Geofisica e Vulcanologia (INGV carried out a multidisciplinary oceanographic cruise, named “Ferdinandea 2012”, the preliminary results of which represent the aim of this paper. The cruise goal was the mapping of the morpho-structural features of some submarine volcanic centres located in the northwestern side of the Sicily Channel and the temporary recording of their seismic and degassing activity. During the cruise, three OBS/Hs (ocean bottom seismometer with hydrophone were deployed near the Graham, Nerita and Terribile submarine banks. During the following 9 months they have recorded several seismo-acoustic signals produced by both tectonic and volcanic sources. A high-resolution bathymetric survey was achieved on the Graham Bank and on the surrounding submarine volcanic centres. A widespread and voluminous gas bubbles emission was observed by both multibeam sonar echoes and a ROV (remotely operated vehicle along the NW side of the Graham Bank, where gas and seafloor samples were also collected.

  17. Basal accretion, a major mechanism for mountain building in Taiwan revealed in rock thermal history

    Science.gov (United States)

    Chen, Chih-Tung; Chan, Yu-Chang; Lo, Ching-Hua; Malavieille, Jacques; Lu, Chia-Yu; Tang, Jui-Ting; Lee, Yuan-Hsi

    2018-02-01

    Deep tectonic processes are key integral components in the evolution of mountain belts, while observations of their temporal development are generally obscured by thermal resetting, retrograde alteration and structural overprinting. Here we recorded an integrated rock time-temperature history for the first time in the pro-wedge part of the active Taiwan arc-continent collision starting from sedimentation through cleavage-forming state to its final exhumation. The integrated thermal and age results from the Raman Spectroscopy of Carbonaceous Material (RSCM) method, zircon U-Pb laser ablation dating, and in-situ40Ar/39Ar laser microprobe dating suggest that the basal accretion process was crucial to the development of the Taiwanese orogenic wedge. The basal accretion process commenced early in the mountain building history (∼6 Ma) and gradually migrated to greater depths, as constrained by persistent plate convergence and cleavage formation under nearly isothermal state at similar depths until ∼ 2.5 Ma recorded in the early-accreted units. Such development essentially contributed to mountain root growth by the increased depth of the wedge detachment and the downward wedge thickening during the incipient to full collision stages in the Taiwan mountain belt.

  18. Visualizing the sedimentary response through the orogenic cycle using multi-dimensional scaling

    Science.gov (United States)

    Spencer, C. J.; Kirkland, C.

    2015-12-01

    Changing patterns in detrital provenance through time have the ability to resolve salient features of an orogenic cycle. Such changes in the age spectrum of detrital minerals can be attributed to fluctuations in the geodynamic regime (e.g. opening of seaways, initiation of subduction and arc magmatism, and transition from subduction to collisional tectonics with arrival of exotic crustal material). These processes manifest themselves through a variety of sedimentary responses due to basin formation, transition from rift to drift sedimentation, or inversion and basement unroofing. This generally is charted by the presence of older detrital zircon populations during basement unroofing events and is followed by a successive younging in the detrital zircon age signature either through arrival of young island arc terranes or the progression of subduction magmatism along a continental margin. The sedimentary response to the aforementioned geodynamic environment can be visualized using a multi-dimensional scaling approach to detrital zircon age spectra. This statistical tool characterizes the "dissimilarity" of age spectra of the various sedimentary successions, but importantly also charts this measure through time. We present three case studies in which multi-dimensional scaling reveals additional useful information on the style of basin evolution within the orogenic cycle. The Albany-Fraser Orogeny in Western Australia and Grenville Orogeny (sensu stricto) in Laurentia demonstrate clear patterns in which detrital zircon age spectra become more dissimilar with time. In stark contrast, sedimentary successions from the Meso- to Neoproterozoic North Atlantic Region reveal no consistent pattern. Rather, the North Atlantic Region reflects a signature consistent with significant zircon age communication due to a distal position from an orogenic front, oblique translation of terranes, and complexity of the continental margin. This statistical approach provides a mechanism to

  19. The Russian-Kazakh Altai orogen: An overview and main debatable issues

    Directory of Open Access Journals (Sweden)

    Inna Safonova

    2014-07-01

    Full Text Available The paper reviews previous and recently obtained geological, stratigraphic and geochronological data on the Russian-Kazakh Altai orogen, which is located in the western Central Asian Orogenic Belt (CAOB, between the Kazakhstan and Siberian continental blocks. The Russian-Kazakh Altai is a typical Pacific-type orogen, which represents a collage of oceanic, accretionary, fore-arc, island-arc and continental margin terranes of different ages separated by strike-slip faults and thrusts. Evidence for this comes from key indicative rock associations, such as boninite- and turbidite (graywacke-bearing volcanogenic-sedimentary units, accreted pelagic chert, oceanic islands and plateaus, MORB-OIB-protolith blueschists. The three major tectonic domains of the Russian-Kazakh Altai are: (1 Altai-Mongolian terrane (AMT; (2 subduction-accretionary (Rudny Altai, Gorny Altai and collisional (Kalba-Narym terranes; (3 Kurai, Charysh-Terekta, North-East, Irtysh and Char suture-shear zones (SSZ. The evolution of this orogen proceeded in five major stages: (i late Neoproterozoic–early Paleozoic subduction-accretion in the Paleo-Asian Ocean; (ii Ordovician–Silurian passive margin; (iii Devonian–Carboniferous active margin and collision of AMT with the Siberian continent; (iv late Paleozoic closure of the PAO and coeval collisional magmatism; (v Mesozoic post-collisional deformation and anarogenic magmatism, which created the modern structural collage of the Russian-Kazakh Altai orogen. The major still unsolved problem of Altai geology is origin of the Altai-Mongolian terrane (continental versus active margin, age of Altai basement, proportion of juvenile and recycled crust and origin of the middle Paleozoic units of the Gorny Altai and Rudny Altai terranes.

  20. Structure of the Orogenic Wedge in the Bhutan Himalaya: First Results from the GANSSER Seismic Experiment

    Science.gov (United States)

    Singer, J.; Hetényi, G.; Diehl, T.; Kissling, E. H.

    2014-12-01

    In the Eastern Himalaya, the structure of the orogenic wedge above the subducting Indian lithosphere and even the Moho topography of the latter are poorly constrained at present. The Main Himalayan Thrust (MHT) is considered a crustal-scale detachment that marks the plate boundary separating the bottom of the orogenic wedge from the top of the Indian crust. In western and central Himalaya portions of the MHT have been imaged by receiver functions (RF) from the surface near the foothills of the Himalayan front range to mid-crustal depths. In Bhutan, however, the MHT and other major thrust geometries at depth remain a matter of debate, without direct geophysical image. Furthermore, earthquake activity in Bhutan seems to be significantly lower compared to most other parts of the Himalayan arc and there appears to be a lack of great earthquakes. This lower level of seismicity could be related to a more ductile deformation in the orogenic wedge, or, alternatively, result from a currently locked situation of the thrust system. In this work, we use data of a densely spaced, temporary seismic network in Bhutan (GANSSER experiment) to determine lithospheric and intra-crustal discontinuities in the Eastern Himalaya with RF complemented by seismic velocities derived from simultaneous inversion of local earthquake data. Along two south-north profiles across the Himalayan range in eastern and western Bhutan the geometry of the dipping Indian Moho is defined by migrated RF images including a dip correction. Based on the characteristics of the RF, the dip and strike of the Moho is independently defined and the occurrence of intra-crustal conversion interfaces like the MHT are mapped across the orogenic wedge. In combination with the geometry of the intra-crustal seismic structure, we use the seismic velocities and the hypocenters of local earthquakes to discuss the predominant deformation type in the orogenic wedge in Bhutan and the potential for large earthquakes in this region

  1. Taiwan: Major U.S. Arms Sales Since 1990

    National Research Council Canada - National Science Library

    Kan, Shirley

    2008-01-01

    .... Congress has oversight of the Taiwan Relations Act (TRA), P.L. 96-8, which has governed arms sales to Taiwan since 1979, when the United States recognized the People's Republic of China (PRC) instead of Taiwan...

  2. Severe Dengue Fever Outbreak in Taiwan

    Science.gov (United States)

    Wang, Sheng-Fan; Wang, Wen-Hung; Chang, Ko; Chen, Yen-Hsu; Tseng, Sung-Pin; Yen, Chia-Hung; Wu, Deng-Chyang; Chen, Yi-Ming Arthur

    2016-01-01

    Dengue fever (DF) is a vector-borne disease caused by dengue viruses (DENVs). Epidemic dengue occurs intermittently in Taiwan. In 2014, Taiwan experienced its largest DF outbreak. There were 15,732 DF cases reported. There were a total of 136 dengue hemorrhagic fever (DHF) cases, of which 20 resulted in death. Most DF cases were reported in southern Taiwan. A total of 15,043 (96%) cases were from Kaohsiung, a modern city in southern Taiwan. This report reviews DF epidemics in Taiwan during 2005–2014. The correlation between DF and DHF along with temperature and precipitation were conjointly examined. We conclude that most dengue epidemics in Taiwan resulted from imported DF cases. Results indicate three main factors that may have been associated with this DF outbreak in Kaohsiung: an underground pipeline explosion combined with subsequent rainfall and higher temperature. These factors may have enhanced mosquito breeding activity, facilitating DENV transmission. PMID:26572871

  3. Methanoculleus sediminis sp. nov., a methanogen from sediments near a submarine mud volcano.

    Science.gov (United States)

    Chen, Sheng-Chung; Chen, Mei-Fei; Lai, Mei-Chin; Weng, Chieh-Yin; Wu, Sue-Yao; Lin, Saulwood; Yang, Tsanyao F; Chen, Po-Chun

    2015-07-01

    A mesophilic, hydrogenotrophic methanogen, strain S3Fa(T), was isolated from sediments collected by Ocean Researcher I cruise ORI-934 in 2010 near the submarine mud volcano MV4 located at the upper slope of south-west Taiwan. The methanogenic substrates utilized by strain S3Fa(T) were formate and H2/CO2 but not acetate, secondary alcohols, methylamines, methanol or ethanol. Cells of strain S3Fa(T) were non-motile, irregular cocci, 0.5-1.0 μm in diameter. The surface-layer protein showed an Mr of 128,000.The optimum growth conditions were 37 °C, pH 7.1 and 0.17 M NaCl. The DNA G+C content of the genome of strain S3Fa(T) was 62.3 mol%. Phylogenetic analysis revealed that strain S3Fa(T) was most closely related to Methanoculleus marisnigri JR1(T) (99.3% 16S rRNA gene sequence similarity). Genome relatedness between strain S3Fa(T) and Methanoculleus marisnigri JR1(T) was computed using both genome-to-genome distance analysis (GGDA) and average nucleotide identity (ANI) with values of 46.3-55.5% and 93.08%, respectively. Based on morphological, phenotypic, phylogenetic and genomic relatedness data, it is evident that strain S3Fa(T) represents a novel species of the genus Methanoculleus, for which the name Methanoculleus sediminis sp. nov. is proposed. The type strain is S3Fa(T) ( = BCRC AR10044(T) = DSM 29354(T)).

  4. Childhood Atopic Dermatitis in Taiwan.

    Science.gov (United States)

    Wang, I-Jen; Wang, Jiu-Yao; Yeh, Kuo-Wei

    2016-04-01

    The prevalence of atopic dermatitis (AD) appears to have increased dramatically over the past decades. It is generally believed that such rapid increase in prevalence cannot be explained fully by genetic factors. Environmental factors might play a role in such an increment. Children with AD are most likely to suffer considerable school absences, family stress, and health care expenditures. Because the onset of AD occurs relatively early in life, identification of early life risk factors and early management for AD to prevent the development of atopic march are of critical importance. However, there is still no consensus on coordinated prevention and management for AD in Taiwan. In this review, we discuss the specific risk factors of AD and important results of recent articles on AD from Taiwan. The management and prevention strategies of AD for Asian skin are also discussed. Copyright © 2016. Published by Elsevier B.V.

  5. Childhood Atopic Dermatitis in Taiwan

    Directory of Open Access Journals (Sweden)

    I-Jen Wang

    2016-04-01

    Full Text Available The prevalence of atopic dermatitis (AD appears to have increased dramatically over the past decades. It is generally believed that such rapid increase in prevalence cannot be explained fully by genetic factors. Environmental factors might play a role in such an increment. Children with AD are most likely to suffer considerable school absences, family stress, and health care expenditures. Because the onset of AD occurs relatively early in life, identification of early life risk factors and early management for AD to prevent the development of atopic march are of critical importance. However, there is still no consensus on coordinated prevention and management for AD in Taiwan. In this review, we discuss the specific risk factors of AD and important results of recent articles on AD from Taiwan. The management and prevention strategies of AD for Asian skin are also discussed.

  6. Crisis in the Taiwan Strait

    Science.gov (United States)

    1997-09-01

    large measure by continued access to foreign sources of weapons and technology. Barring major upheavals in Chinese foreign policy, it is likely that...is little prospect for breakthroughs in any of the related equipment areas, barring massive infusions of expensive foreign assistance; and it does...Beijing’s term, near and then very near Taiwan reveal more than Beijing brava - do; have the stodgy Central Military Commission and die-hard PLA

  7. Occupational Neurotoxic Diseases in Taiwan

    Directory of Open Access Journals (Sweden)

    Chi-Hung Liu

    2012-12-01

    Full Text Available Occupational neurotoxic diseases have become increasingly common in Taiwan due to industrialization. Over the past 40 years, Taiwan has transformed from an agricultural society to an industrial society. The most common neurotoxic diseases also changed from organophosphate poisoning to heavy metal intoxication, and then to organic solvent and semiconductor agent poisoning. The nervous system is particularly vulnerable to toxic agents because of its high metabolic rate. Neurological manifestations may be transient or permanent, and may range from cognitive dysfunction, cerebellar ataxia, Parkinsonism, sensorimotor neuropathy and autonomic dysfunction to neuromuscular junction disorders. This study attempts to provide a review of the major outbreaks of occupational neurotoxins from 1968 to 2012. A total of 16 occupational neurotoxins, including organophosphates, toxic gases, heavy metals, organic solvents, and other toxic chemicals, were reviewed. Peer-reviewed articles related to the electrophysiology, neuroimaging, treatment and long-term follow up of these neurotoxic diseases were also obtained. The heavy metals involved consisted of lead, manganese, organic tin, mercury, arsenic, and thallium. The organic solvents included n-hexane, toluene, mixed solvents and carbon disulfide. Toxic gases such as carbon monoxide, and hydrogen sulfide were also included, along with toxic chemicals including polychlorinated biphenyls, tetramethylammonium hydroxide, organophosphates, and dimethylamine borane. In addition we attempted to correlate these events to the timeline of industrial development in Taiwan. By researching this topic, the hope is that it may help other developing countries to improve industrial hygiene and promote occupational safety and health care during the process of industrialization.

  8. Subduction and Slab Advance at Orogen Syntaxes: Predicting Exhumation Rates and Thermochronometric Ages with Numerical Modeling

    Science.gov (United States)

    Nettesheim, Matthias; Ehlers, Todd A.; Whipp, David M.

    2017-04-01

    The change in plate boundary orientation and subducting plate geometry along orogen syntaxes may have major control on the subduction and exhumation dynamics at these locations. Previous work documents that the curvature of subducting plates in 3D at orogen syntaxes forces a buckling and flexural stiffening of the downgoing plate. The geometry of this stiffened plate region, also called indenter, can be observed in various subduction zones around the world (e.g. St. Elias Range, Alaska; Cascadia, USA; Andean syntaxis, South America). The development of a subducting, flexurally stiffened indenter beneath orogen syntaxes influences deformation in the overriding plate and can lead to accelerated and focused rock uplift above its apex. Moreover, the style of deformation in the overriding plate is influenced by the amount of trench or slab advance, which is the amount of overall shortening not accommodated by underthrusting. While many subduction zones exhibit little to no slab advance, the Nazca-South America subduction and especially the early stages of the India-Eurasia collision provide end-member examples. Here, we use a transient, lithospheric-scale, thermomechanical 3D model of an orogen syntaxis to investigate the effects of subducting a flexurally stiffened plate geometry and slab advance on upper plate deformation. A visco-plastic upper-plate rheology is used, along with a buckled, rigid subducting plate. The free surface of the thermomechanical model is coupled to a landscape evolution model that accounts for erosion by fluvial and hillslope processes. The cooling histories of exhumed rocks are used to predict the evolution of low-temperature thermochronometer ages on the surface. With a constant overall shortening for all simulations, the magnitude of slab advance is varied stepwise from no advance, with all shortening accommodated by underthrusting, to full slab advance, i.e. no motion on the megathrust. We show that in models where most shortening is

  9. [Medical-physiological characteristics of combat training of nuclear-power submarine crews].

    Science.gov (United States)

    Dovgusha, V V; Myznikov, I L; Shalabodov, S A; Bumaĭ, O K

    2009-10-01

    The article presents an observe of general questions of peculiarities of military-professional activity of submarine staff These questions are defining value in ideology of medical supply of submarine troops of NAVY in now-days conditions. The article also presents the statistics of morbidity in long termed sails for last forty years, it's dynamics by different categories of sail staff, on different stages of combat training activity in dependence of perioditation of work cycle of submarine staff The authors have examined modern condition of medical supply of submarines; have presented statistics of quality indexes of health of submarine staff The authors have formed main problems of medical supply of submarines and have proposed ways of their solving on modern stage.

  10. Losses in armoured three-phase submarine cables

    DEFF Research Database (Denmark)

    Ebdrup, Thomas; Silva, Filipe Miguel Faria da; Bak, Claus Leth

    2014-01-01

    increases the losses in armoured cables compared to unarmoured cables. In this paper a thorough state of the art analysis is conducted on armour losses in three-phase armoured submarine power cables. The analysis shows that the IEC 60287-1-1 standard overestimates the armour losses which lead...... to the installation of cables with excessive phase conductor cross section. This paper also presents an example of the potential economic benefits of having a better knowledge of the losses introduced by the armour.......The number of offshore wind farms will keep increasing in the future as a part of the shift towards a CO2 free energy production. The energy harvested from the wind farm must be brought to shore, which is often done by using a three-phase armoured submarine power cable. The use of an armour...

  11. Stresses in a submarine topography under ocean waves

    Energy Technology Data Exchange (ETDEWEB)

    Mei, C.C.; McTigue, D.F.

    1984-01-01

    The problem of submarine slope stability is of interest to both offshore engineering and geology. In an uneven topography, the weight above a horizontal plane induces two-dimensional variation in the static stress field. The action of wave pressure, which changes with depth, further introduces excess pore pressure and dynamic stresses in the sea bottom. In the present paper, we combine a simple analytical theory for the static stress by the present authors, and the recent solution by Mei and Foda for wave-induced stresses in a plane poro-elastic sea bed to account for mild bottom slope and wave shoaling, to obtain the effective stress field in a submarine topography under sea waves. Sample results are given for a ridge and a canyon. In particular the dynamic pore pressure and the combined static and dynamic effective stresses are presented. 10 references, 11 figures.

  12. Stresses in a submarine topography under ocean waves

    Energy Technology Data Exchange (ETDEWEB)

    Mei, C.C.; McTigue, D.F.

    1984-09-01

    The problem of submarine slope stability is of interest to both offshore engineering and geology. In an uneven topography, the weight above a horizontal plane induces two-dimensional variation in the static stress field. The action of wave pressure, which changes with depth, further introduces excess pore pressure and dynamic stresses in the sea bottom. In the present paper, we combine a simple analytical theory for the static stress by the present authors, and the recent solution by Mei and Foda for wave-induced stresses in a plane poro-elastic sea bed to account for mild bottom slope and wave shoaling, and obtain the effective stress field in a submarine topography under sea waves. Sample results are given for a ridge and a canyon. In particular, the dynamic pore pressure and the combined static and dynamic effective stresses are presented.

  13. Improving Situational Awareness on Submarines Using Augmented Reality

    Science.gov (United States)

    2008-09-01

    COSO ) are several pages of guidance for the evolution available to the watch officer for reference. There are also Operating Procedures that the watch...officer must follow to ensure the safe ascent to PD. The COSOs are specific to the each CO. The OPs are specific to a class of submarine. The...evolution in the framework described above can provide valuable insight to the capabilities of the proposed system. This of course is a hypothetical

  14. Analysis of SSN 688 Class Submarine Maintenance Delays

    Science.gov (United States)

    2017-06-01

    errors an in-depth analysis into the job-level maintenance is required which is outside the scope of this analysis. 25 2. New Work Causes Late...attempting to determine the cause of this trend. Finally, this thesis proposes a solution to the systematic underestimation of availability durations by...illustrating the inherent error in the current equation and providing a notional equation to remove that error . 14. SUBJECT TERMS Submarine

  15. Submarine Pressure Hull Collapse Considering Corrosion and Penetrations

    Science.gov (United States)

    2010-11-01

    corrosion. Des valeurs de la pression d’écrasement sont calculées pour les diverses dimensions de la zone de corrosion, et ce, dans les cas de présence ou...Research & Development Canada DRDIM Director Research and Development Knowledge and Information Management OOC Out-of-circularity R&D Research...Support SLA (Mr. John Porter) 1 Project Manager , Submarine Scientific Support SLA (LCdr Wade Temple) 9 TOTAL LIST PART I LIST PART II: External

  16. Europe’s Grand Canyon: Nazaré submarine canyon

    OpenAIRE

    Tyler, P.; Amaro, T.; Arzola, R.; Cunha; Stigter, H. de; Gooday, A.; Huvenne, V.; Ingels, J; Kiriakoulakis, K; Lastras, G.; Masson, D.; Oliveira, A.; Pattenden, A.; Vanreusel, A.; van Weering, T.

    2009-01-01

    The Nazare submarine canyon extends similar to 210 km westward from the coast of Portugal, down to a water depth of > 4300 m. The considerable habitat heterogeneity found throughout the canyon is affected by strong currents and high turbidity, especially in the upper parts of the canyon. The canyon morphology comprises steep slopes, scarps, terraces, and overhangs, and a deeply incised thalweg is found in the lower part of the canyon. The seabed within the canyon is composed of varying propor...

  17. Submarine and Autonomous Vessel Proliferation: Implications for Future Strategic Stability at Sea

    Science.gov (United States)

    2012-12-01

    replace the Ohio- class SSBN and Virginia -class SSN to replace the Los Angeles class attack submarine. Although more sophisticated than their...predecessors and with some modifications to demands of the post-Cold War era and (in the Virginia class) an emphasis on littoral conflict, these purchases...Congressional Research Service analyst Amy Woolf observes: “With few submarines in the fleet, the Navy would have to reduce the number of submarines on

  18. The future of the ballistic missile submarine force in the Russian nuclear triad

    OpenAIRE

    Lesiw, Richard T.

    2008-01-01

    Approved for public release; distribution is unlimited This thesis analyzes the current status of the Russian Federation's ballistic missile submarine force. It reviews the history of the ballistic missile submarine force, its current status, and the implementation of plans currently in progress and as well as the advantages and disadvantages of maintaining a ballistic missile submarine force. This thesis also assesses the other two legs of the nuclear triad - the intercontinental balli...

  19. Gender Integration on U.S. Navy Submarines: Views of the First Wave

    Science.gov (United States)

    2015-06-01

    submarines is to perform seek-and-destroy missions on enemy ships and submarines, conduct surveillance and reconnaissance, provide covert troop insertion...not only the missile payload they were designed to carry but also extended periods at sea without resupply. In terms of berthing and sanitary ...officer berthing and sanitary 28 facilities on board Ohio class submarines, however, no significant modifications would be necessary in order to

  20. Navy Virginia (SSN-774) Class Attack Submarine Procurement: Background and Issues for Congress

    Science.gov (United States)

    2016-02-12

    reactors or non- nuclear power sources such as diesel engines or fuel cells. All U.S. Navy submarines are nuclear - powered. A submarine’s use of...the Navy’s plan to design and procure a next - generation ballistic missile submarine called the Ohio Replacement Program or SSBN(X). 26...the next several years require these submarines to use up their nuclear fuel cores more quickly than the Navy now projects, then the amounts of time

  1. Navy Virginia (SSN 774) Class Attack Submarine Procurement: Background and Issues for Congress

    Science.gov (United States)

    2016-10-25

    powered attack submarines (SSNs). The SSNs are general -purpose submarines that can (when appropriately equipped and armed) perform a variety of...signs of tampering. The defective elbow pipe, used to funnel steam from the reactor to the sub’s propulsion turbines and generators , showed evidence of...Congressional Research Service Summary The Navy has been procuring Virginia (SSN-774) class nuclear- powered attack submarines since FY1998. The two Virginia

  2. Fuel-cell-propelled submarine-tanker-system study

    Energy Technology Data Exchange (ETDEWEB)

    Court, K E; Kumm, W H; O' Callaghan, J E

    1982-06-01

    This report provides a systems analysis of a commercial Arctic Ocean submarine tanker system to carry fossil energy to markets. The submarine is to be propelled by a modular Phosphoric Acid Fuel Cell system. The power level is 20 Megawatts. The DOE developed electric utility type fuel cell will be fueled with methanol. Oxidant will be provided from a liquid oxygen tank carried onboard. The twin screw submarine tanker design is sized at 165,000 deadweight tons and the study includes costs and an economic analysis of the transport system of 6 ships. The route will be under the polar icecap from a loading terminal located off Prudhoe Bay, Alaska to a transshipment facility postulated to be in a Norwegian fjord. The system throughput of the gas-fed methanol cargo will be 450,000 barrels per day. The total delivered cost of the methanol including well head purchase price of natural gas, methanol production, and shipping would be $25/bbl from Alaska to the US East Coast. Of this, the shipping cost is $6.80/bbl. All costs in 1981 dollars.

  3. Estimating the empirical probability of submarine landslide occurrence

    Science.gov (United States)

    Geist, Eric L.; Parsons, Thomas E.; Mosher, David C.; Shipp, Craig; Moscardelli, Lorena; Chaytor, Jason D.; Baxter, Christopher D. P.; Lee, Homa J.; Urgeles, Roger

    2010-01-01

    The empirical probability for the occurrence of submarine landslides at a given location can be estimated from age dates of past landslides. In this study, tools developed to estimate earthquake probability from paleoseismic horizons are adapted to estimate submarine landslide probability. In both types of estimates, one has to account for the uncertainty associated with age-dating individual events as well as the open time intervals before and after the observed sequence of landslides. For observed sequences of submarine landslides, we typically only have the age date of the youngest event and possibly of a seismic horizon that lies below the oldest event in a landslide sequence. We use an empirical Bayes analysis based on the Poisson-Gamma conjugate prior model specifically applied to the landslide probability problem. This model assumes that landslide events as imaged in geophysical data are independent and occur in time according to a Poisson distribution characterized by a rate parameter λ. With this method, we are able to estimate the most likely value of λ and, importantly, the range of uncertainty in this estimate. Examples considered include landslide sequences observed in the Santa Barbara Channel, California, and in Port Valdez, Alaska. We confirm that given the uncertainties of age dating that landslide complexes can be treated as single events by performing statistical test of age dates representing the main failure episode of the Holocene Storegga landslide complex.

  4. Pockmark morphology and turbulent buoyant plumes at a submarine spring

    Science.gov (United States)

    Buongiorno Nardelli, B.; Budillon, F.; Watteaux, R.; Ciccone, F.; Conforti, A.; De Falco, G.; Di Martino, G.; Innangi, S.; Tonielli, R.; Iudicone, D.

    2017-09-01

    The input flow of groundwater from the seabed to the coastal ocean, known as Submarine Groundwater Discharge (SGD), has been only recently recognized as an important component of continental margin systems. It potentially impacts physical, chemical and biological marine dynamics. Independently of its specific nature (seepage, submarine springs, etc.) or fluid chemical composition, a SGD is generally characterized by low flow rates, hence making its detection and quantification very difficult, and explaining why it has been somewhat neglected by the scientific community for a long time. Along with the growing interest for SGDs emerged the need for in-situ observations in order to characterize in details how these SGDs behave. In this work, we describe the morphology of a pockmark field, detected in the Southern Tyrrhenian Sea (Mediterranean Sea), and provide observational evidences of the presence of active submarine springs over the coastal shelf area. We describe the effect of the fluid seeps on the water column stratification close to the main plumes and in the neighbouring areas, providing quantitative estimates of the intensity of the turbulent mixing and discussing their potential impact on the seabed morphology and pockmark formation in the context of turbulent buoyant plumes analytical modelling.

  5. Long-term eruptive activity at a submarine arc volcano.

    Science.gov (United States)

    Embley, Robert W; Chadwick, William W; Baker, Edward T; Butterfield, David A; Resing, Joseph A; de Ronde, Cornel E J; Tunnicliffe, Verena; Lupton, John E; Juniper, S Kim; Rubin, Kenneth H; Stern, Robert J; Lebon, Geoffrey T; Nakamura, Ko-ichi; Merle, Susan G; Hein, James R; Wiens, Douglas A; Tamura, Yoshihiko

    2006-05-25

    Three-quarters of the Earth's volcanic activity is submarine, located mostly along the mid-ocean ridges, with the remainder along intraoceanic arcs and hotspots at depths varying from greater than 4,000 m to near the sea surface. Most observations and sampling of submarine eruptions have been indirect, made from surface vessels or made after the fact. We describe here direct observations and sampling of an eruption at a submarine arc volcano named NW Rota-1, located 60 km northwest of the island of Rota (Commonwealth of the Northern Mariana Islands). We observed a pulsating plume permeated with droplets of molten sulphur disgorging volcanic ash and lapilli from a 15-m diameter pit in March 2004 and again in October 2005 near the summit of the volcano at a water depth of 555 m (depth in 2004). A turbid layer found on the flanks of the volcano (in 2004) at depths from 700 m to more than 1,400 m was probably formed by mass-wasting events related to the eruption. Long-term eruptive activity has produced an unusual chemical environment and a very unstable benthic habitat exploited by only a few mobile decapod species. Such conditions are perhaps distinctive of active arc and hotspot volcanoes.

  6. Association of orogenic activity with the Ordovician radiation of marine life

    Science.gov (United States)

    Miller, A. I.; Mao, S.

    1995-01-01

    The Ordovician radiation of marine life was among the most substantial pulses of diversification in Earth history and coincided in time with a major increase in the global level of orogenic activity. To investigate a possible causal link between these two patterns, the geographic distributions of 6576 individual appearances of Ordovician vician genera around the world were evaluated with respect to their proximity to probable centers of orogeny (foreland basins). Results indicate that these genera, which belonged to an array of higher taxa that diversified in the Middle and Late Ordovician (trilobites, brachiopods, bivalves, gastropods, monoplacophorans), were far more diverse in, and adjacent to, foreland basins than they were in areas farther removed from orogenic activity (carbonate platforms). This suggests an association of orogeny with diversification at that time.

  7. Miocene thrusting in the eastern Sila Massif: Implication for the evolution of the Calabria-Peloritani orogenic wedge (southern Italy)

    Science.gov (United States)

    Vignaroli, G.; Minelli, L.; Rossetti, F.; Balestrieri, M. L.; Faccenna, C.

    2012-05-01

    Alpine orogens in the central Mediterranean region have revealed the concomitance of crustal extension in back-arc domain and crustal shortening in frontal domain. Quantitative data of deformation in the frontal orogenic wedges are necessary to understand how the shortening-extension pair evolves in terms of structures, orogenic transport, timing, and exhumation rate. This paper deals with kinematics and ages of the frontal thrust systems of the Calabria-Peloritani Arc (Italy) exposed in the eastern Sila Massif. We first present structural fieldwork, onshore and offshore well log data, and new apatite fission-track (AFT) thermochronology. Then, we describe the structural architecture of the studied area as an ENE-verging stacking of thrust sheets involving basement units and syn-orogenic sediments. The AFT study documents that thrust sheets entered the partial annealing zone from 18 Ma to 13 Ma. This Early-Middle Miocene thrusting phase was coeval with exhumation of high-pressure/low temperature metamorphic rocks in the hinterland of the orogen (Coastal Chain area), mainly driven by top-to-the-W extensional tectonics. Opposite kinematic shear senses (contractional top-to-the-E and extensional top-to-the-W) and different exhumation rates (slow in the frontal, more rapid in the hinterland) are framed in a tectonic scenario of a critically tapered orogenic wedge during the eastward retreating of the Apennine slab.

  8. Nature and provenance of the Beishan Complex, southernmost Central Asian Orogenic Belt

    Science.gov (United States)

    Zheng, Rongguo; Li, Jinyi; Xiao, Wenjiao; Zhang, Jin

    2017-08-01

    The ages and origins of metasedimentary rocks, which were previously mapped as Precambrian, are critical in rebuilding the orogenic process and better understanding the Phanerozoic continental growth in the Central Asian Orogenic Belt (CAOB). The Beishan Complex was widely distributed in the southern Beishan Orogenic Collage, southernmost CAOB, and their ages and tectonic affinities are still in controversy. The Beishan Complex was previously proposed as fragments drifted from the Tarim Craton, Neoproterozoic Block or Phanerozoic accretionary complex. In this study, we employ detrital zircon age spectra to constrain ages and provenances of metasedimentary sequences of the Beishan Complex in the Chuanshanxun area. The metasedimentary rocks here are dominated by zircons with Paleoproterozoic-Mesoproterozoic age ( 1160-2070 Ma), and yield two peak ages at 1454 and 1760 Ma. One sample yielded a middle Permian peak age (269 Ma), which suggests that the metasedimentary sequences were deposited in the late Paleozoic. The granitoid and dioritic dykes, intruding into the metasedimentary sequences, exhibit zircon U-Pb ages of 268 and 261 Ma, respectively, which constrain the minimum deposit age of the metasedimentary sequences. Zircon U-Pb ages of amphibolite (274 and 216 Ma) indicate that they might be affected by multi-stage metamorphic events. The Beishan Complex was not a fragment drifted from the Tarim Block or Dunhuang Block, and none of cratons or blocks surrounding Beishan Orogenic Collage was the sole material source of the Beishan Complex due to obviously different age spectra. Instead, 1.4 Ga marginal accretionary zones of the Columbia supercontinent might have existed in the southern CAOB, and may provide the main source materials for the sedimentary sequences in the Beishan Complex.

  9. Topography and subduction geometry in the central Andes: Clues to the mechanics of a noncollisional orogen

    Science.gov (United States)

    Gephart, John W.

    1994-01-01

    The central Andeean orogen between 12 deg and 32 deg S latitude exhibits a high degree of spatial order: principally an extraordinary bilateral symmetry that is common to the Earth's surface, the underlying Wadati-Benioff zone, and the Nazca/South America plate kinematics, which has been stable since the mid-Tertiary. This spatial order must reflect the physical mechanisms of mountain building in this noncollisional orogen. The shapes of the topography and subduction zone can be reduced to symmetric and antisummeric components relative to any verical symmetry plane; the particular plaen which minimizes the antisymmetry (and maximizes the symmetry) is well resolved and is essentially coincident with the stable Euler equator of Nacza/South America relative motion since the mid-Tertiary. That the topography, subduction geometry, and persistent mid-Tertiary plate kinematics share common spatial and geometric elements suggests that he distribution of topography in this orogen depends strongly on the dynamics of subduction. Other factors that might affect the topography and underlying tectonics, such as climate and inherited strutura fabric, which have different spatial characterisitcs, must be of less significance at a continental scale. Furthermore, the small components of asymmetry among the various elements of the orogen appear to be mutually relate in a simple way; it is possible that this coupled asymmetry is associated with a late Teriary change in plate kinematics. These observations suggest that there is a close connection between plate tectonics and the form of the Earth's surface in this noncollisional setting. It follows hta the distribution of topography near convergent plate boundaries may provide a powerful constraing for understanding the dynamics of subduction.

  10. The susceptibility of large river basins to orogenic and climatic drivers

    Science.gov (United States)

    Haedke, Hanna; Wittmann, Hella; von Blanckenburg, Friedhelm

    2017-04-01

    Large rivers are known to buffer pulses in sediment production driven by changes in climate as sediment is transported through lowlands. Our new dataset of in situ cosmogenic nuclide concentration and chemical composition of 62 sandy bedload samples from the world largest rivers integrates over 25% of Earth's terrestrial surface, distributed over a variety of climatic zones across all continents, and represents the millennial-scale denudation rate of the sediment's source area. We can show that these denudation rates do not respond to climatic forcing, but faithfully record orogenic forcing, when analyzed with respective variables representing orogeny (strain rate, relief, bouguer anomaly, free-air anomaly), and climate (runoff, temperature, precipitation) and basin properties (floodplain response time, drainage area). In contrast to this orogenic forcing of denudation rates, elemental bedload chemistry from the fine-grained portion of the same samples correlates with climate-related variables (precipitation, runoff) and floodplain response times. It is also well-known from previous compilations of river-gauged sediment loads that the short-term basin-integrated sediment export is also climatically controlled. The chemical composition of detrital sediment shows a climate control that can originate in the rivers source area, but this signal is likely overprinted during transfer through the lowlands because we also find correlation with floodplain response times. At the same time, cosmogenic nuclides robustly preserve the orogenic forcing of the source area denudation signal through of the floodplain buffer. Conversely, previous global compilations of cosmogenic nuclides in small river basins show the preservation of climate drivers in their analysis, but these are buffered in large lowland rivers. Hence, we can confirm the assumption that cosmogenic nuclides in large rivers are poorly susceptible to climate changes, but are at the same time highly suited to detect

  11. Climate protection laws in Taiwan; Klimaschutzrecht in Taiwan

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, Yen-Lin Agnes [Fu Jen Catholic Univ., Taipei, Taiwan (China). School of Law

    2014-07-01

    The contribution on climate protection laws in Taiwan is first describing the international position and cooperation with UNFCCC, The national climate protection policy covers energy and industry, trading and economy, forestry and agriculture, traffic and local affairs, society and education. The description of the actual legislation includes the constitutional framework, environmental legislation, air pollution legislation, environmental compatibility regulations, renewable energy development legislation, energy management laws, legal drafts concerning reduction of greenhouse gas emission and energy taxes. Finally the competences and responsibilities of authorities are summarized.

  12. Scientific Ocean Drilling to Assess Submarine Geohazards along European Margins

    Science.gov (United States)

    Ask, M. V.; Camerlenghi, A.; Kopf, A.; Morgan, J. K.; Ocean DrillingSeismic Hazard, P. E.

    2008-12-01

    Submarine geohazards are some of the most devastating natural events in terms of lives lost and economic impact. Earthquakes pose a big threat to society and infrastructure, but the understanding of their episodic generation is incomplete. Tsunamis are known for their potential of striking coastlines world-wide. Other geohazards originating below the sea surface are equally dangerous for undersea structures and the coastal population: submarine landslides and volcanic islands collapse with little warning and devastating consequences. The European scientific community has a strong focus on geohazards along European and nearby continental margins, especially given their high population densities, and long historic and prehistoric record of hazardous events. For example, the Mediterranean is surrounded by very densely-populated coastline and is the World's leading holiday destination, receiving up 30% of global tourism. In addition, its seafloor is criss-crossed by hydrocarbon pipelines and telecommunication cables. However, the governing processes and recurrence intervals of geohazards are still poorly understood. Examples include, but are not limited to, earthquakes and volcanic eruptions along the active tectonic margins of the Mediterranean and Sea of Marmara, landslides on both active and passive margins, and tsunamites and seismites in the sedimentary record that suggest a long history of similar events. The development of geophysical networks, drilling, sampling and long-term monitoring are crucial to the understanding of earthquake, landslide, and tsunami processes, and to mitigate the associated risks in densely populated and industrialized regions such as Europe. Scientific drilling, particularly in the submarine setting, offers a unique tool to obtain drill core samples, borehole measurements and long-term observations. Hence, it is a critical technology to investigate past, present, and possible future influences of hazardous processes in this area. The

  13. History and development of ophthalmology in Taiwan

    Directory of Open Access Journals (Sweden)

    Yu-Chih Hou

    2016-12-01

    Full Text Available Western medicine was first introduced to Taiwan by medical missionaries in the mid-19th century. Modernization of medicine was systematically transplanted to Taiwan in the Japanese colonial period, and ophthalmology was established third among hospital departments, following internal medicine and surgery. Dr Hidetaka Yamaguchi, an ophthalmologist, was the first head of the Taihoku Hospital, later known as National Taiwan University Hospital (NTUH; Taipei, Taiwan. Ophthalmologists during the colonial period conducted studies on tropical and infectious eye diseases. After World War II, ophthalmologists at NTUH played an important role in medical education, residency training, studies, and teaching. Dr Yan-Fei Yang established the Taiwan Ophthalmological Society in 1960 and instituted its official journal in 1962. Dr Ho-Ming Lin established the Department of Ophthalmology at the Tri-Service General Hospital in the 1950s and the Veterans General Hospital in the 1960s. Taiwan ophthalmologists eradicated trachoma by 1971. Cataract surgery and penetrating keratoplasty were initially performed in the 1960s. Currently, there are about 1600 ophthalmologists in Taiwan conducting an estimated 120,000 cataract surgeries and 600 corneal transplantations annually. Many subspecialty societies have been established recently that serve to educate Taiwanese ophthalmologists and to connect with international ophthalmic societies. Taiwan ophthalmologists continue to contribute to the advancement of ophthalmic knowledge globally.

  14. 75 FR 61175 - Polyvinyl Alcohol From Taiwan

    Science.gov (United States)

    2010-10-04

    ... COMMISSION Polyvinyl Alcohol From Taiwan AGENCY: United States International Trade Commission. ACTION... of polyvinyl alcohol, provided for in subheading 3905.30.00 of the Harmonized Tariff Schedule of the... of polyvinyl alcohol from Taiwan are being sold in the United States at less than fair value within...

  15. An isotopic perspective on growth and differentiation of Proterozoic orogenic crust: From subduction magmatism to cratonization

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Simon P.; Korhonen, Fawna J.; Kirkland, Christopher L.; Cliff, John B.; Belousova, Elena A.; Sheppard, Stephen

    2017-01-01

    The in situ chemical differentiation of continental crust ultimately leads to the long-term stability of the continents. This process, more commonly known as ‘cratonization’, is driven by deep crustal melting with the transfer of those melts to shallower regions resulting in a strongly chemically stratified crust, with a refractory, dehydrated lower portion overlain by a complementary enriched upper portion. Since the lower to mid portions of continental crust are rarely exposed, investigation of the cratonization process must be through indirect methods. In this study we use in situ Hf and O isotope compositions of both magmatic and inherited zircons from several felsic magmatic suites in the Capricorn Orogen of Western Australia to highlight the differentiation history (i.e. cratonization) of this portion of late Archean to Proterozoic orogenic crust. The Capricorn Orogen shows a distinct tectonomagmatic history that evolves from an active continental margin through to intracratonic reworking, ultimately leading to thermally stable crust that responds similarly to the bounding Archean Pilbara and Yilgarn Cratons.

  16. Quantitative insights into the role of gravitational collapse in major orogenic belts

    Directory of Open Access Journals (Sweden)

    E. Mantovani

    2006-06-01

    Full Text Available Abstract Previous works have proposed gravitational collapse as the driving mechanism of extensional deformation of thickened continental crust. In this work we investigate the physical plausibility of this interpretation for the most important orogenic belts of the world by computing the spreading force induced by lateral variations of crustal thickness and the possible resisting forces. Two collapse mechanisms, one involving the upper crust only and the other the whole crust, have been considered. Particular attention has been devoted to constrain the uncertainty affecting such computations, mostly due to the large variability of the thermal and mechanical properties of rocks. The results obtained show that gravitational collapse is not a plausible mechanism in the four Mediterranean orogens here considered (Northern Apennines, Calabrian Arc, Hellenic Arc and Carpathians. For the other orogenic zones we have taken into account (Western U.S. Cordillera, Central Andes, Himalayas and Central Alps, the large uncertainty that affects the estimate of spreading and resisting forces does not allow to firmly assess the feasibility of gravitational collapse.

  17. Tsunami Generated by a Two-Phase Submarine Debris Flow

    Science.gov (United States)

    Pudasaini, S. P.

    2012-04-01

    The general two-phase debris flow model proposed by Pudasaini (2011) is employed to study subaerial and submarine debris flows, and the tsunami generated by the debris impact at lakes and oceans. The model includes several essential physical aspects, including Mohr-Coulomb plasticity for the solid stress, while the fluid stress is modelled as a solid volume fraction gradient enhanced non-Newtonian viscous stress. The generalized interfacial momentum transfer includes the viscous drag, buoyancy, and the virtual mass. The generalized drag covers both the solid-like and fluid-like contributions, and can be applied to linear to quadratic drags. Strong couplings exist between the solid and the fluid momentum transfer. The advantage of the real two-phase debris flow model over classical single-phase or quasi-two-phase models is that by considering the solid (and/or the fluid) volume fraction appropriately, the initial mass can be divided into several (even mutually disjoint) parts; a dry (landslide or rock slide), a fluid (water or muddy water; e.g., dams, rivers), and a general debris mixture material as needed in real flow simulations. This offers a unique and innovative opportunity within a single framework to simultaneously simulate (a) the sliding debris (or landslide), (b) the water lake or ocean, (c) the debris impact at the lake or ocean, (d) tsunami generation and propagation, (e) mixing and separation between the solid and the fluid phases, and (f) sediment transport and deposition process in the bathymetric surface. The new model is applied to two-phase subaerial and submarine debris flows. Benchmark numerical simulations reveal that the dynamics of the debris impact induced tsunamis are fundamentally different than the tsunami generated by pure rock avalanche and landslides. Special attention is paid to study the basic features of the debris impact to the mountain lakes or oceans. This includes the generation, amplification and propagation of the multiple

  18. Morphologic and Process Transformation at a Barrier Island of Taiwan

    Science.gov (United States)

    Lin, T.

    2006-12-01

    Waisanding Barrier, the largest barrier island off the southwestern coast of Taiwan, has undergone morphologic and process transformation in recent decades. Based on the analysis of historical maps and aerial photographs, the island has migrated both southward and eastward (or landward). The shoreline at the northwest tip of the island has a retreat rate at 65 m/year, and the shoreline at the southern end migrates at a speed of 88 m/year southeastward. The overall land area has shrunken. Topographic profile surveys also show the great reduction of dune fields and the dune heights. This is mainly due to the starvation of sand sources. Three main processes have been proposed to explain the island migration: (1) the southward- dominant longshore drift; (2) the overwash process; and (3) the prevailing southward aeolian sand transport. Choushui river, the largest river in Taiwan, is the major sediment source for the Waisanding Barrier. Improvement constructions and illegal sand/gravel mining of the river may reduce large amounts of sediments that reach the shore. An artificial industrial park project located at the south of Choushui river mouth may also play an important role in blocking and preventing some of the southward longshore sand transport from reaching Waisanding Barrier. A permanent loss of sand to a submarine channel at the southern end had probably worsened the sediment storage of the barrier island. The strong wind transport during winter and the overwash process during spring high tides or stormy conditions may reduce the foredune and overall elevation of the island. This landform modification may result in the increase of overwash frequencies that move more sand landward and lower the elevation. As the results, the original back shore and dune field area are developed into a wide sandy tidal flat with many shallow tidal creeks formed during rising high tide stages. Because of all the landform changes in recent decades, the barrier island may undergo the

  19. 76 FR 13982 - Antidumping Duty Order: Polyvinyl Alcohol From Taiwan

    Science.gov (United States)

    2011-03-15

    ... International Trade Administration Antidumping Duty Order: Polyvinyl Alcohol From Taiwan AGENCY: Import... Department is issuing an antidumping duty order on polyvinyl alcohol (PVA) from Taiwan. DATES: Effective Date... value in the antidumping duty investigation of PVA from Taiwan. See Polyvinyl Alcohol From Taiwan: Final...

  20. Window into the Caledonian orogen: Structure of the crust beneath the East Shetland platform, United Kingdom

    Science.gov (United States)

    McBride, J.H.; England, R.W.

    1999-01-01

    Reprocessing and interpretation of commercial and deep seismic reflection data across the East Shetland platform and its North Sea margin provide a new view of crustal subbasement structure beneath a poorly known region of the British Caledonian orogen. The East Shetland platform, east of the Great Glen strike-slip fault system, is one of the few areas of the offshore British Caledonides that remained relatively insulated from the Mesozoic and later rifting that involved much of the area around the British Isles, thus providing an "acoustic window" into the deep structure of the orogen. Interpretation of the reflection data suggests that the crust beneath the platform retains a significant amount of its original Caledonian and older architecture. The upper to middle crust is typically poorly reflective except for individual prominent dipping reflectors with complex orientations that decrease in dip with depth and merge with a lower crustal layer of high reflectivity. The three-dimensional structural orientation of the reflectors beneath the East Shetland platform is at variance with Caledonian reflector trends observed elsewhere in the Caledonian orogen (e.g., north of the Scottish mainland), emphasizing the unique tectonic character of this part of the orogen. Upper to middle crustal reflectors are interpreted as Caledonian or older thrust surfaces that were possibly reactivated by Devonian extension associated with post-Caledonian orogenic collapse. The appearance of two levels of uneven and diffractive (i.e., corrugated) reflectivity in the lower crust, best developed on east-west-oriented profiles, is characteristic of the East Shetland platform. However, a north-south-oriented profile reveals an interpreted south-vergent folded and imbricated thrust structure in the lower crust that appears to be tied to the two levels of corrugated reflectivity on the east-west profiles. A thrust-belt origin for lower crustal reflectivity would explain its corrugated

  1. Molybdenite Re Os dating constrains gravitational collapse of the Sveconorwegian orogen, SW Scandinavia

    Science.gov (United States)

    Bingen, Bernard; Stein, Holly J.; Bogaerts, Michel; Bolle, Olivier; Mansfeld, Joakim

    2006-04-01

    Re-Os dating of molybdenite from small deposits is used to define crustal domains exhibiting ductile versus brittle behaviour during gravitational collapse of the Sveconorwegian orogen in SW Scandinavia. A 1019 ± 3 Ma planar quartz vein defines a minimum age for brittle behaviour in central Telemark. In Rogaland-Vest Agder, molybdenite associated with deformed quartz and pegmatite veins formed between 982 ± 3 and 947 ± 3 Ma in the amphibolite-facies domain (three deposits) and between 953 ± 3 and 931 ± 3 Ma west of the clinopyroxene-in isograd (two deposits) in the vicinity of the 0.93-0.92 Ga Rogaland anorthosite complex. The data constrain the last increment of ductile deformation to be younger than 0.95 and 0.93 Ga in these two metamorphic zones, respectively. Molybdenite is the product of an equilibrium between biotite, oxide and sulfide minerals and a fluid or hydrated melt phase, after the peak of 1.03-0.97 Ga regional metamorphism. Molybdenite precipitation is locally episodic. A model for gravitational collapse of the Sveconorwegian orogen controlled by lithospheric extension after 0.97 Ga is proposed. In the west of the orogen, the Rogaland-Vest Agder sector is interpreted as a large shallow gneiss dome, formed slowly in two stages in a warm and structurally weak crust. The first stage at 0.96-0.93 Ga was associated with intrusion of the post-collisional hornblende-biotite granite suite. The second stage at 0.93-0.92 Ga, restricted to the southwesternmost area, was associated with intrusion of the anorthosite-mangerite-charnockite suite. Most of the central part of the orogen was already situated in the brittle upper crust well before 0.97 Ga, and did not undergo significant exhumation during collapse. In the east of the orogen, situated against the colder cratonic foreland, exhumation of high-grade rocks of the Eastern Segment occurred between 0.97 and 0.95 Ga, and included preservation of high-pressure rocks but no plutonism.

  2. Clandestine labor migration to Taiwan.

    Science.gov (United States)

    Tsay, C

    1992-01-01

    "Illegal migration to Taiwan is a recent phenomenon but with a rapid rate of increase. Most illegal foreign workers enter on visitor's visas and overstay. This paper's detailed analysis of official data reveals that Malaysia, Philippines, Indonesia and Thailand are the major sources, providing a stock of mostly male workers numbering around 40,000. Sociodemographic and attitudinal changes among Taiwanese workers coupled with labor shortages in low-skilled jobs are pressuring the Taiwanese government to formulate plans for a systematic importation of foreign labor." excerpt

  3. Toward A Tectonic Synthesis Of Taiwan With TAIGER Data

    Science.gov (United States)

    Wu, F. T.; Kuo-Chen, H.; Lavier, L. L.; Unsworth, M. J.; Bertrand, E. A.

    2009-12-01

    New results from TAIGER experiments yielded data reflecting the overall orogenic processes in play in the young Taiwan orogeny. Two salient sets of observations are used here. In the new tomography [Hao et al., this meeting] based TAIGER deployments as well as permanent broadband network the crust and upper mantle are imaged. With both land and OBS data, we double the network aperture in the EW direction from about 100 km to nearly 200 km and extend the depth of adequate resolution to about 180 km. The systematic variation of the upper mantle high velocity anomaly from south to north shows active subduction south of 23°N, but further north the anomalous zone steepens and loses definition gradually. This variation is coupled with the clear increase of crusta thickness north of 23°N. Inspecting results of geodynamic modeling [Logan et al., this meeting] and considering the junction of Ryukyu subduction zone [Wu et al., 2009] we think that two factors could contribute to the transition. At each point along the trend of Taiwan, the trend-perpendicular shortening of the Asian continental lithosphere coupled with the mobilization of the Central Range due to weathering would begin after the continental margin and the Luzon arc collided. The ensuing rapid exhumation led to the down-thrust of the arc and the forced steepening of the subduction zone. The subduction of the Eurasian plate would then stop and the lithospheric collision would build mountains. This scenario essentially diachronously propagated southward as the collision engaged the continental margin successively, creating the variations in the dip of the former subduction zone unitl to about 23°N. At the same time, the northwestward moving Ryukyu subduction zone may have interfered with the subducted Eurasian plate under northern Taiwan and contributed to changing its geometry. The other significant observation is the resistivity profile from magnetotellurics [Bertrand et al., 2009]. Besides the well

  4. [Anatomy cadaver ceremonies in Taiwan].

    Science.gov (United States)

    Kao, T; Ha, H

    1999-07-01

    The practice of holding annual ceremonies in honor of cadaver donors in Taiwan's medical schools has a history of nearly a hundred years. It originated in Japan, where such ceremonies have been widely held in medical schools since the practice was founded by Toyo Yamawaki, who was the first medical scholar in Japan to engage in dissection of the human body and was the author of the first anatomy book to appear in Japan, the Zoshi. The practice of holding donor ceremonies was introduced into Taiwan after the Jaiwu Sino - Japanese war, when the island became a Japanese colony. The tradition was upheld in the Viceroy's Medical School, the Viceroy's College of Medicine, and Taihoku (Taipei) Imperial University College of Medicine, and continued since the restoration of Chinese power to the present. The practice of holding cadaver donor ceremonies in institutions of medical education is intended to express respect for the donor as well as to encourage the practice of cadaver donation to the benefit of medical education.

  5. The Impact of the General Board of the Navy on Interwar Submarine Design

    Science.gov (United States)

    2009-06-12

    Navy had developed the Gato class submarine, which was successful independently operating in the vast Pacific Ocean in support of War Plan Orange. The...development of the Gato class submarine, which was successful independently operating in the vast Pacific Ocean in support of War Plan Orange. The...

  6. Procurements by the Non-Acoustic Anti-Submarine Warfare Program Through the Environmental Technologies Laboratory

    Science.gov (United States)

    1994-06-14

    General, DoD, on contract offloading, including Report No. 93-068, " Procurement of Services for the Non-Acoustic Anti-Submarine Warfare Program...contract administration in response to Audit Report No. 93-042. Report No. 93-068, " Procurement of Services for the Non-Acoustic Anti- Submarine Warfare

  7. Study on the locational criteria for submarine rock repositories of low and medium level radioactive wastes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, G. H.; Kang, W. J.; Kim, T. J. and others [Chungnam National Univ., Taejon (Korea, Republic of)

    1992-01-15

    Submarine repositories have significant advantages over their land counterparts locating close to the areas of daily human activities. Consequently, the construction of submarine repositories on the vast continental shelves around Korean seas is considered to be highly positive. In this context, the development of locational criteria primarily targeting the safety of submarine rock repositories is very important.The contents of the present study are: analyzing characteristics of marine environment: Search of potential hazards to, and environmental impact by, the submarine repositories; Investigation of the oceanographic, geochemical, ecological and sedimentological characteristics of estuaries and coastal seas. Locating potential hazards to submarine repositories by: Bibliographical search of accidents leading to the destruction of submarine structures by turbidity currents and other potentials; Review of turbidity currents. Consideration of environmental impact caused by submarine repositories: Logistics to minimize the environmental impacts in site selection; Removal and dispersion processes of radionuclides in sea water. Analyses of oceanographical characteristics of, and hazard potentials in, the Korean seas. Evaluation of the MOST 91-7 criteria for applicability to submarine repositories and the subsequent proposition of additional criteria.

  8. Submarine landslides on the north continental slope of the South China Sea

    Science.gov (United States)

    Wang, Weiwei; Wang, Dawei; Wu, Shiguo; Völker, David; Zeng, Hongliu; Cai, Guanqiang; Li, Qingping

    2018-02-01

    Recent and paleo-submarine landslides are widely distributed within strata in deep-water areas along continental slopes, uplifts, and carbonate platforms on the north continental margin of the South China Sea (SCS). In this paper, high-resolution 3D seismic data and multibeam data based on seismic sedimentology and geomorphology are employed to assist in identifying submarine landslides. In addition, deposition models are proposed that are based on specific geological structures and features, and which illustrate the local stress field over entire submarine landslides in deep-water areas of the SCS. The SCS is one of the largest fluvial sediment sinks in enclosed or semi-enclosed marginal seas worldwide. It therefore provides a set of preconditions for the formation of submarine landslides, including rapid sediment accumulation, formation of gas hydrates, and fluid overpressure. A new concept involving temporal and spatial analyses is tested to construct a relationship between submarine landslides and different time scale trigger mechanisms, and three mechanisms are discussed in the context of spatial scale and temporal frequency: evolution of slope gradient and overpressure, global environmental changes, and tectonic events. Submarine landslides that are triggered by tectonic events are the largest but occur less frequently, while submarine landslides triggered by the combination of slope gradient and over-pressure evolution are the smallest but most frequently occurring events. In summary, analysis shows that the formation of submarine landslides is a complex process involving the operation of different factors on various time scales.

  9. The risk of hydrogen explosion in a submarine p.I Catalytic combustion of hydrogen

    Directory of Open Access Journals (Sweden)

    Kłos Ryszard

    2016-09-01

    Full Text Available The series of articles discuss issues related to conducting high risk projects on the example of modernisation of hydrogen incinerators on a submarine. The article depicts a technical problem situation connected with catalytic hydrogen combustion on a submarine.

  10. Post-eruptive Submarine Terrace Development of Capelinhos, Azores

    Science.gov (United States)

    Zhongwei Zhao, Will; Mitchell, Neil; Quartau, Rui; Tempera, Fernando; Bricheno, Lucy

    2017-04-01

    Erosion of the coasts of volcanic islands by waves creates shallow banks, but how erosion proceeds with time to create them and how it relates to wave climate is unclear. In this study, historical and recent marine geophysical data collected around the Capelinhos promontory (western Faial Island, Azores) offer an unusual opportunity to characterize how a submarine terrace developed after the eruption. The promontory was formed in 1957/58 during a Surtseyan eruption that terminated with extensive lava forming new rocky coastal cliffs. Historical measurements of coastline position are supplemented here with coastlines measured from 2004 and 2014 Google Earth images in order to characterize coastline retreat rate and distance for lava- and tephra-dominated cliffs. Swath mapping sonars were used to characterize the submarine geometry of the resulting terrace (terrace edge position, gradient and morphology). Limited photographs are available from a SCUBA dive and drop-down camera deployments to ground truth the submarine geomorphology. The results reveal that coastal retreat rates have decreased rapidly with the time after the eruption, possibly explained by the evolving resistance to erosion of cliff base materials. Surprisingly, coastline retreat rate decreases with terrace width in a simple inverse power law with terrace width. We suspect this is only a fortuitous result as wave attenuation over the terrace will not obviously produce the variation, but nevertheless it shows how rapidly the retreat rate declines. Understanding the relationship between terrace widening shelf and coastal cliff retreat rate may be more widely interesting if they can be used to understand how islands evolve over time into abrasional banks and guyots.

  11. Maximizing the probability an aerial anti-submarine torpedo detects its target

    Science.gov (United States)

    Wang, Zhi-Jie

    2009-06-01

    As a result of the high speed of anti-submarine patrol aircraft as well as their wide range, high efficiency and other characteristics, aerial torpedoes released by anti-submarine patrol aircraft have become the key anti submarine tool. In order to improve operational efficiency, a deep study was made of the target detection probabilities for aerial torpedoes released by anti-submarine patrol aircraft. The operational modes of aerial torpedoes were analyzed and mathematical-simulation models were then established. The detection probabilities of three attacking modes were then calculated. Measures were developed for improving low probabilities of detection when attacking a probable target position. This study provides an important frame of reference for the operation of aerial torpedo released by anti-submarine patrol aircraft.

  12. Main devices design of submarine oil-water separation system

    Science.gov (United States)

    Cai, Wen-Bin; Liu, Bo-Hong

    2017-11-01

    In the process of offshore oil production, in order to thoroughly separate oil from produced fluid, solve the environment problem caused by oily sewage, and improve the economic benefit of offshore drilling, from the perspective of new oil-water separation, a set of submarine oil-water separation devices were designed through adsorption and desorption mechanism of the polymer materials for crude oil in this paper. The paper introduces the basic structure of gas-solid separation device, periodic separation device and adsorption device, and proves the rationality and feasibility of this device.

  13. Submarine glaciated landscapes of central and northern British Columbia, Canada

    Science.gov (United States)

    Shaw, John; Lintern, Gwyn

    2015-04-01

    Recent systematic multibeam sonar mapping and ground-truthing surveys in the fjords and coastal waters of central and northern British Columbia, Canada, provide information on glacial processes associated with the Cordilleran Ice Sheet, and also on postglacial processes that have strongly modified the glacial terrain. During the last glacial maximum, ice covered the Coast Range, except for nunataks. Convergent streamlined glacial landforms in the Strait of Georgia testify to a strong flow of ice towards the southeast, between Vancouver Island and the mainland. During ice retreat, thick deposits of acoustically stratified glaciomarine mud were deposited in glacially over deepened basins. Retreat through the Douglas Channel fjord system was punctuated by still stands, resulting in a series of submarine moraines. Postglacial processes have created a suite of landforms that mask the primary glacial terrain: 1) Fjord floors host thick deposits of acoustically transparent postglacial mud with highly variable distribution: banks up to 80-m thick are commonly adjacent to erosional zones with glaciomarine mud exposed at the seafloor; 2) In this region of high precipitation and snowpack melt, numerous cone-shaped Holocene fan deltas developed on the fjord sidewalls transport coarse sediment to the fjord floors. Larger deltas are developed at fjord heads, notably at Kitimat and Kildala; 3) Submarine slope failures in this tectonically active area have resulted in a suite of mass transport deposits on sidewalls and fjord floors. The very large submarine slope failures at Camano Sound and KitKat Inlet occurred on the steep, rear facets of large transverse moraines, and involved the failure of glaciomarine sediment that moved into deeper basins, perhaps as a retrogressive failure. The ages of these events are unknown, although the presence of postglacial mud in the slide scar at Caamano suggests that the event at that location occurred in the late glacial or early Holocene. Also

  14. Micro-tunneling as an alternative to submarine cable

    Energy Technology Data Exchange (ETDEWEB)

    Russo, D.A. [Seattle City Light, WA (United States); Hansen, D. [CH2M Hill, Bellevue, WA (United States)

    1994-12-31

    The geography that gives Seattle its beauty can pose unique challenges for the engineers attempting to provide service to the customers who live near or upon these features. Steep, wooded hills and greenbelts create familiar problems of construction and right-of-way maintenance. The waterways and adjoining shoreline zones present a more difficult set of requirements. When Seattle City Light determined it was necessary to install 2-26 KV feeders across the Salmon Bay waterway, they discovered that submarine cables could not be used. Shallow angle directional drilling and micro-tunneling were examined and it was fond that a microtunneled duct bank was the best method to use.

  15. [Nursing manpower and solutions in Taiwan].

    Science.gov (United States)

    Teng, Su-Wen

    2014-04-01

    The shortage of nursing manpower is a long-term problem worldwide that affects Taiwan despite this country's internationally admired achievements in terms of its healthcare and national health insurance systems. This article reviews discussions related to the nursing shortage issue published by the World Health Organization, International Council of Nurses, and Taiwan Ministry of Health and Welfare. Next, an overview is given of the nursing workforce profile, causal factors behind the nursing shortage, and demand for and supply of nursing manpower. Finally, problems, resolutions, and expected outcomes for the nursing shortage in Taiwan are analyzed.

  16. Zircon (U-Th)/He evidence for pre-Eocene orogenic exhumation of eastern North Pyrenean massifs, France

    Science.gov (United States)

    Ternois, Sébastien; Vacherat, Arnaud; Pik, Raphaël; Ford, Mary; Tibari, Bouchaïb

    2017-04-01

    Orogens and their associated foreland basins are considered as part of a single dynamic system evolving from an early, non equilibrated, growth stage to a late, mature, steady-state stage. Most of our understanding in foreland basins, in particular early convergence-stage deposition, comes from the subducting plate, so that the classic paradigm for foreland basins is the pro-wedge. Models that clearly depict the relationship between erosion of the orogenic wedge and sedimentation into its associated foreland basin only focus on the late post-orogenic phase. Relatively little is known and understood about the very long phase of initiation of orogenesis. In the doubly wedged Pyrenean orogen, where we know and understand relatively little about how the early retro-wedge developed, the record of the onset of orogenic denudation from massifs is quite limited, not only in time but also in space. As part of the OROGEN project funded by TOTAL and the BRGM, this study presents first single-grain zircon (U-Th)/He data from two Palaeozoic massifs of the external Northern Pyrenean Zone, the Agly and Salvezines massifs. It aims at constraining the exhumation history of eastern Pyrenean massifs and understanding what is their significance for early orogenic wedge growth. The Pyrenean orogeny was generated from end Santonian (84 Ma) to Oligocene-Miocene due to convergence of the Iberian and European plates. Aquitaine foreland basin history (Ariège region) indicates that convergence took place in two phases, Campanian to Maastrichian and Eocene, separated by a quiet Paleocene phase. Yet, only Eocene cooling events are recorded by low-temperature thermochronometers in the central Pyrenean massifs (Arize and Trois-Seigneurs). Nine bedrock samples were collected along a WNW-ESE traverse (Salvezines and Saint-Arnac granites, Belesta-Caramany gneisses) and analysed for ZHe dating. Zircon (U-Th)/He data for the Agly and Salvezines massifs, together with forward modelling of data for

  17. Chronological constraints on tectonic evolution of the Chinese Tianshan Orogen through detrital zircons from modern and paleo-river sands

    Science.gov (United States)

    Ren, Rong; Guan, Shuwei; Han, Baofu

    2017-04-01

    The Chinese Tianshan Orogen marked the prolonged, complicated interactions between the southwestern Paleo-Asian Ocean and surrounding blocks. Massive new and previous detrital zircon U-Pb chronological data from modern and paleo-river sands (more than 7000 ages from 102 samples) were compiled to constrain its tectonic evolution. The Chinese Tianshan Orogen is characterized by predominant Paleozoic and minor Mesozoic and Precambrian detrital zircon ages that show multimodal characteristic. The oldest Phanerozoic zircon population (peak at 475 Ma) results from subduction and closure of the Early Paleozoic Terskey Ocean. But the absence of this peak in Chinese North and southern South Tianshan suggests that the subductions of the North and South Tianshan oceans may not initiate until Late Ordovician, with subsequent 460-390 Ma and 360-320 Ma arc magmatism. Similar to magmatic suite in classic collisional orogens, the youngest massive 320-270 Ma magmatism is supposed to be post-collisional. The North and South Tianshan oceans therefore probably had their closure to form the Chinese Tianshan Orogen during Late Carboniferous. The weak Mesozoic intra-plate magmatism further argues against a Late Permian-Triassic Tianshan Orogen for the lack of extensive syn- and post-collisional magmatism. Moreover, the diverse Precambrian detrital zircon age patterns indicate that the surrounding blocks have distinct tectonic evolution and short-term amalgamation during the Neoproterozoic.

  18. Study of water mixing in the coastal waters of the western Taiwan Strait based on radium isotopes.

    Science.gov (United States)

    Men, Wu; Jiang, Yuwu; Liu, Guangshan; Wang, Fenfen; Zhang, Yusheng

    2016-02-01

    Radium is considered to be a useful tracer for studying the physical processes of seawater. In this work, three naturally occurring radium isotopes, (224)Raex, (226)Ra and (228)Ra, were measured in the coastal zone of the western Taiwan Strait during the summer seasons. Based on the distributions of the three radium isotopes and the salinity, we conclude that the water mixing pattern in the study area in summer consists of diluted water flowing from the Jiulong River to the open sea towards the east and southeast, and open sea seawater flowing inward from south to north. The submarine ground water discharges in the estuarine region, as suggested by the radium and salinity data. The residence times of the Jiulong River estuary, ranging from 7 to 49 d, were estimated using the radium isotope pairs (224)Raex and (226)Ra. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Discriminating fluid source regions in orogenic gold deposits using B-isotopes

    Science.gov (United States)

    Lambert-Smith, James S.; Rocholl, Alexander; Treloar, Peter J.; Lawrence, David M.

    2016-12-01

    The genesis of orogenic gold deposits is commonly linked to hydrothermal ore fluids derived from metamorphic devolatilization reactions. However, there is considerable debate as to the ultimate source of these fluids and the metals they transport. Tourmaline is a common gangue mineral in orogenic gold deposits. It is stable over a very wide P-T range, demonstrates limited volume diffusion of major and trace elements and is the main host of B in most rock types. We have used texturally resolved B-isotope analysis by secondary ion mass spectrometry (SIMS) to identify multiple fluid sources within a single orogenic gold ore district. The Loulo Mining District in Mali, West Africa hosts several large orogenic gold ore bodies with complex fluid chemistry, associated with widespread pre-ore Na- and multi-stage B-metasomatism. The Gara deposit, as well as several smaller satellites, formed through partial mixing between a dilute aqueous-carbonic fluid and a hypersaline brine. Hydrothermal tourmaline occurs as a pre-ore phase in the matrix of tourmalinite units, which host mineralization in several ore bodies. Clasts of these tourmalinites occur in mineralized breccias. Disseminated hydrothermal and vein hosted tourmaline occur in textural sites which suggest growth during and after ore formation. Tourmalines show a large range in δ11B values from -3.5 to 19.8‰, which record a change in fluid source between paragenetic stages of tourmaline growth. Pre-mineralization tourmaline crystals show heavy δ11B values (8-19.8‰) and high X-site occupancy (Na ± Ca; 0.69-1 apfu) suggesting a marine evaporite source for hydrothermal fluids. Syn-mineralization and replacement phases show lighter δ11B values (-3.5 to 15.1‰) and lower X-site occupancy (0.62-0.88 apfu), suggesting a subsequent influx of more dilute fluids derived from devolatilization of marine carbonates and clastic metasediments. The large, overlapping range in isotopic compositions and a skew toward the

  20. Needs Assessment for Exchange Students in Taiwan

    Directory of Open Access Journals (Sweden)

    Kentei Takaya

    2016-04-01

    Full Text Available With the growing mobility of international students in Asia and the Pacific, Taiwan has become actively involved in promoting international academic exchange. This research investigates the experience of exchange students from the Philippines and mainland China and examines their needs while studying in Taiwan. Qualitative in-depth interviews were conducted with exchange students from the Philippines and mainland China. The findings suggest that while exchange students from the Philippines and mainland China both encountered difficulties during their study in Taiwan, exchange students from the Philippines were inclined to encounter more difficulties compared to those from mainland China due to language difficulties. Based on the findings of this study, suggested support services for future exchange students in Taiwan are outlined to match the needs of students from both Chinese and non-Chinese-speaking backgrounds.

  1. Newly discovered native orchids of Taiwan (X

    Directory of Open Access Journals (Sweden)

    Tsan-Piao LIN

    2017-11-01

    Full Text Available This report presents three new orchids of Taiwan, i.e., Habenaria alishanensis T.P. Lin & D.M. Huang, Neottia cinsbuensis T.P. Lin & D.M. Huang, and Nephelaphyllum tenuiflorum Blume.

  2. Late Cenozoic Climate Change and its Implications on the Denudation of Orogen Syntaxes

    Science.gov (United States)

    Mutz, Sebastian; Ehlers, Todd

    2017-04-01

    The denudation history of active orogens is often interpreted in the context of modern climate gradients. Despite the influence of climatic conditions on erosion rates, information about paleoclimate evolution is often not available and thus not considered when denudation histories are interpreted. In this study, we analyze output from paleoclimate simulations conducted with ECHAM5-wiso at T159 (ca. 80x80km) resolution. Specifically, we analyze simulations of pre-industrial (PI, pre-1850), Mid-Holocene (MH, ca. 6ka), Last Glacial Maximum (LGM, ca. 21ka) and Pliocene (PLIO, ca. 3ka) climates and focus on a selection of orogen syntaxes as study regions (e.g. Himalaya, SE Alaska, Cascadia, and Central Andes). For the selected region, we carry out a cluster analysis using a hybrid of hierarchical and k-means clustering procedures using mean annual temperature (MAT), temperature amplitude, mean annual precipitation (MAP), precipitation amplitude and u-wind and v-wind in different months to provide a general overview of paleoclimates in the study regions. Additionally, we quantify differences between paleoclimates by applying two-group linear discrimination analyses to the simulation output for a similar selection of variables. Results indicate the largest differences to the PI climate are observed for the LGM and PLIO climates in the form of widespread cooling and reduced precipitation in the LGM and warming and enhanced precipitation during the PLIO. These global trends can be observed for most locations in the investigated areas, but the strength varies regionally and the trends in precipitation are less uniform than trends in temperatures. The LGM climate shows the largest deviation in annual precipitation from the PI climate, and shows enhanced precipitation in the temperate Andes, and coastal regions for both SE Alaska and the US Pacific Northwest Pacific. Furthermore, LGM precipitation is reduced in the western Himalayas and enhanced in the eastern Himalayas

  3. EARLY STAGE OF THE CENTRAL ASIAN OROGENIC BELT BUILDING: EVIDENCES FROM THE SOUTHERN SIBERIAN CRATON

    OpenAIRE

    D. P. Gladkochub; T. V. Donskaya; Shihong Zhang; S. A. Pisarevsky; A. M. Stanevich; A. M. Mazukabzov; Z. L. Motova

    2017-01-01

    The origin of the Central-Asian Orogenic Belt (CAOB), especially of its northern segment nearby the southern margin of the Siberian craton (SC) is directly related to development and closure of the Paleo-Asian Ocean (PAO). Signatures of early stages of the PAO evolution are recorded in the Late Precambrian sedimentary successions of the Sayan-Baikal-Patom Belt (SBPB) on the southern edge of SC. These successions are spread over 2000 km and can be traced along this edge from north-west (Sayan ...

  4. The pre-orogenic detrital zircon record of the Variscan orogeny: Preliminary results

    Science.gov (United States)

    Stephan, Tobias; Kroner, Uwe

    2017-04-01

    To test plate-tectonic constellations in consideration of the long-term development of sedimentary transport paths, temporally and spatially highly resolved records of provenance analysis are mandatory. The interpretation of existing studies focus on small-scale areas within an orogen thereby neglecting the differing distribution of provenance data in the entire orogenic system. This study reviews a large data set of compiled geochronological data to document the development of pre-orogenic tectonic units on the example of the Variscan orogeny. Constrained by tectonic and geological models, the temporal distribution of U-Pb detrital zircon ages, used as a proxy for sedimentary provenance, shows that some minima and maxima of zircon abundance are nearly synchronous for thousands of kilometres along the orogeny. Age spectra of Precambrian to Lower Palaeozoic samples were constructed on the basis of 38729 U-Pb ages from 685 samples that were compiled from 102 publications. The age compilation combines thermal ionization mass spectrometry (TIMS), laser ablation-inductively coupled plasma-mass spectrometer (LA-ICP-MS), sensitive high-resolution ion microprobe (SHRIMP), and secondary ion mass spectrometry (SIMS) analyses. The data was re-processed using a common age calculation and concordance filter to ensure comparability. The concordance of each zircon grain was calculated from 206Pb/238U and 207Pb/235U ages to guarantee that only concordant grains, i.e., with 3) is used for the maximum age of deposition. In addition to the location of >600 samples, the precise depositional ages result in a spatially and temporally high resolution. To avoid the different levels of analytical precision of the compiled TIMS, LA-ICP-MS, SHRIMP, and SIMS data, detrital zircon ages are plotted as kernel density estimates. Spatial and temporal distribution of the kernel density estimates, as well as further statistical techniques (e.g. multidimensional scaling) are used to discriminate

  5. Relating orogen width to shortening, erosion, and exhumation during Alpine collision

    OpenAIRE

    Rosenberg, Claudio L.; Berger, A.; Bellahsen, Nicolas; Bousquet, R.

    2015-01-01

    International audience; We investigate along-strike width changes of the thickened, accreted lower plate (TALP) in the Central and in the Eastern Alps. We set the width of the TALP in relation to the inferred amount of collisional shortening and exhumation along six orogen-scale cross sections. Taking the present-day, along-strike gradients in the amount of collisional shortening to represent the temporal evolution of the collisional wedge, it may be concluded that the cross-sectional area of...

  6. Seismicity and sedimentation rate effects on submarine slope stability

    Science.gov (United States)

    Ten Brink, U. S.; Andrews, B. D.; Miller, N. C.

    2016-12-01

    Large submarine mass-transport scars are commonly observed on continental margins, but are noticeably less abundant on margins that experience frequent earthquakes than on those that seldom experience them. This is a surprising observation, given that horizontal acceleration from earthquakes and associated strength loss from cyclic loading and liquefaction are commonly thought to provide the primary triggers for inducing failures and subsequent mass movements. Mapping submarine failure scars in ten margins worldwide, we find decreasing scar abundance with both increasing frequency of earthquakes and decreasing sedimentation rate. The decrease in scar abundance is interpreted to represent increasing slope stability. The increase in stability is non linear (power law with btectonic activity (salt diapirs, seamount subduction, etc.) leads to relatively rapid oversteepening of the slope, implying that the morphology of most margins is in fact, stable over many earthquake cycles. Note that the above correlation averages scar area and sedimentation rate over entire margin areas. Variations in sedimentation rate with time, such as over glacial-interglacial cycles, and intra-margin variations in seismic attenuation, sedimentation rate, composition, and pore pressure, have likely affected the abundance of slope failures in time and space.

  7. An Automatic Procedure for the Quantitative Characterization of Submarine Bedforms

    Directory of Open Access Journals (Sweden)

    Massimo Di Stefano

    2018-01-01

    Full Text Available A model for the extraction and quantitative characterization of submarine landforms from high-resolution digital bathymetry is presented. The procedure is fully automated and comprises two parts. The first part consists of an analytical model which extracts quantitative information from a Digital Elevation Model in the form of objects with similar parametric characteristics (terrain objects. The second part is a rule-based model where the terrain objects are reclassified into distinct landforms with well-defined three dimensional characteristics. For the focus of this work, the quantitative characterization of isolated dunes (height greater than 2 m is used to exemplify the process. The primary metrics used to extract terrain objects are the flatness threshold and the search radius, which are then used by the analytical model to identify the feature type. Once identified as dunes, a sequence of spatial analysis routines is applied to identify and compute metrics for each dune including length, height, width, ray of curvature, slope analysis for each stoss and lee side, and dune symmetry. Dividing the model into two parts, one scale-dependent and another centered around the shape of the landform, makes the model applicable to other submarine landforms like ripples, mega-ripples, and coral reefs, which also have well-defined three-dimensional characteristics.

  8. Fin propulsion on a human-powered submarine

    Science.gov (United States)

    Anderson, Iain A.; Pocock, Benjamin; Harbuz, Antoni; Algie, Cam; Vochezer, Daniel; Chao, Ryan; Lu, Benjamin

    2015-03-01

    Nearly all surface and underwater vessels are driven by screw propulsion; ideal for coupling to rotary engines and well understood after over a century of development. But most aquatic creatures use fins for swimming. Although there are sound evolutionary reasons why fish have fins and not propellers, they are nevertheless agile, fast and efficient. Although fish-like robots such as the MIT Robotuna are providing good insight into fin-based swimming there are advantages for using humans in the experimental device. Like an airplane test pilot they can write crash reports. We present preliminary observations for the human powered finned submarine: Taniwha. The sub participated in the 2nd European International Submarine races in Gosport UK where it received a trophy for "Best Non-Propeller Performance". Two sets of Hobie Mirage fin drives fixed to the upper and lower rear surfaces of the sub are pedaled by the pilot. The pilot also has two levers at the front, one to pitch a pair of dive planes and one for yawing a large rudder. Good speed, we estimate to be greater than 6 m/s is possible with these fins although we haven't explored their full potential. Straying too near the surface or bottom can lead to an instability, synonymous to a stall, such that control is lost. The mechanism for this will be discussed and solutions offered. Fish are 400 million years in front of us but one day we'll catch them.

  9. Are tilt measurements useful in detecting tsunamigenic submarine landslides?

    Science.gov (United States)

    Brune, Sascha; Babeyko, Andrey Y.; Sobolev, Stephan V.

    2009-06-01

    Large submarine landslides can generate dangerous tsunamis. Because of their long-period signal, detection of landslides by common seismological methods is difficult. Here we suggest a method of detecting submarine landslides by using an array of land-based tiltmeters. The displacement of a large volume of sediments during landsliding produces a detectable elastic response of the lithosphere. We propose a technique to calculate this response and to invert for tsunami relevant parameters like slide location, volume, and velocity. We exemplify our method by applying it to the Storegga slide west of Norway and other tsunamigenic landslide events. The parameter which can be most robustly estimated from tiltmeter array measurements is the product of slide volume and its velocity (slide tsunamigenic potential). This parameter also controls the amplitude of the generated tsunami wave. The inversion accuracy of this parameter and the estimated tsunami height near the coast depends on the noise level of tiltmeter measurements, distance of the tiltmeters from the slide, and slide tsunamigenic potential itself. The tsunamigenic potential of the most dangerous slides like Storegga can be estimated well by tiltmeters at the coast if the effective noise level does not exceed 50 nrad.

  10. A submarine fan in the Mesa Central, Mexico

    Science.gov (United States)

    Silva-Romo, G.; Arellano-Gil, J.; Mendoza-Rosales, C.; Nieto-Obregón, J.

    2000-10-01

    The contact between the Guerrero and Sierra Madre tectonostratigraphic terranes has been proposed to lie in the Mesa Central, east of the city of Zacatecas. Marine Triassic units have been assigned to the Guerrero Terrane. It is here proposed that this contact occurs to the west of the city of Zacatecas and the Triassic marine sequence assigned to the Sierra Madre Terrane. We analyzed the stratigraphic record and structural features of pre-Late Jurassic sequences at four localities in the Mesa Central. They contain a marine turbiditic Triassic unit, which includes La Bellena, Taray, and Zacatecas Formations, and a continental unit of probable Middle Jurassic age. Triassic sandstones were derived from a cratonic area, without the influence of arc volcanism. The sequences were affected by two phases of deformation. The Triassic formations are unconformably overlain by a continental volcano-sedimentary sequence that contains fragments of sandstones derived from the underlying unit. Sedimentologic characteristics of the Triassic unit fit a submarine fan model. The submarine fan developed at the continental margin of Pangaea during Triassic times. Turbidite associations in the San Rafael Area indicate a middle fan depositional environment, while in the Real de Catorce Area, they correspond to the distal part (basin plain facies). At La Ballena and Zacatecas the turbidite associations occur in the middle part and perhaps the external part of the fan.

  11. Feasibility study of submarine diesel exhaust valve interspace coating application

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, W.; Zhou, M.; Bibby, D.; Huang, J.

    2008-05-15

    This document described a feasibility study conducted to evaluate surface coating systems applied to the surface of a diesel exhaust valve interspace on a VICTORIA Class submarine. A series of laboratory studies were conducted to determine the physical characteristics of the coatings, which will be subjected to high service temperatures, diesel exhaust gas, and seawater. The valves were made of Q1N steel castings. The surface coatings were designed to provide corrosion resistance and thermal protection to the valves. As part of the study, a survey was conducted on various state-of-the-art surface coating systems. Coatings were rated on their ability to protect the Q10 steel surface from corrosion, high temperatures and seawater. An additional requirement was that the coatings should not produce high amounts of hydrogen. Plating trials were conducted with a nickel-based alloy (Ni-Cu-P) placed on Q1N steel substrates with a hypophosphite reducing agent. The results of X-ray diffraction (XRD) analyses suggested that the coatings can also be used to protect the external surfaces of various submarine components. 54 refs., 4 tabs., 10 figs.

  12. Aquatic organotin pollution in Taiwan.

    Science.gov (United States)

    Meng, Pei-Jie; Lin, Junda; Liu, Li-Lian

    2009-02-01

    The current status of aquatic organotin pollution in Taiwan is reviewed. In freshwater sediments and biota, especially in rice-field related habitats, phenyltins (PTs) were dominant among the organotin pollutants, whereas butyltins (BTs) were usually predominant in marine environments. Among the marine habitats, contamination levels were found to be in the descending order of harbour and estuary>fish cultural site>coastal>offshore>coral reefs. Imposex snails were observed in all the sampling years (1990-2003). Meanwhile, organotin concentrations were greater in winter than those in summer, whereas proportions of PTs were much higher in summer than in winter. Due to the lack of continuous monitoring data, the effectiveness of the ban on TPT usage in agriculture in 1999 and the prohibition of TBT use on small boats in 2003 is still not known.

  13. Naja atra snakebite in Taiwan.

    Science.gov (United States)

    Mao, Yan-Chiao; Liu, Po-Yu; Chiang, Liao-Chun; Lai, Chih-Sheng; Lai, Kuo-Lung; Ho, Cheng-Hsuan; Wang, Te-Huo; Yang, Chen-Chang

    2017-08-23

    Naja atra snakebite is uncommon in Taiwan and causes distinct effects on its victims. Although the Taiwan government produces its own specific antivenom, little information on the management of N. atra snakebite is available. We retrospectively evaluated 183 patients admitted to two medical centers. Of these, 45 were identified as definite cases of N. atra snakebite, 86 as suspected cases, and 52 as clinical cases. Demographic data, symptomatology, and management were compared between these case groups. Symptomatology and management were similar in the three groups. Among the 183 patients, 10 (5.5%) were asymptomatic and nine (4.9%) had transient and partial ptosis or body weakness. The principal effects were local tissue swelling and pain in 173 patients (94.5%), followed by clinically suspected wound infection in 148 (80.9%), skin necrosis in 120 (65.6%), necrotizing soft tissue infection in 77 (42.1%), fever in 59 (32.2%), and gastrointestinal effects in 53 (29%). The median total dose of specific antivenom needed to treat N. atra envenoming was 10 vials. In the envenomed patients, debridement was required in 74 patients (42.8%), fasciotomy/fasciectomy in 46 (26.6%), and finger or toe amputation in seven (4%). The first operation was performed at a median of 3.5 days after the bite. Based on these typical manifestations, clinical diagnosis of N. atra snakebites may be feasible and practical. In contrast to other snakes of Elapidae family, N. atra bite did not cause serious neurological effects. Early surgical consultation should be obtained because half of the patients underwent surgery due to infectious complications. Acute compartment syndrome was the surgical indication in rare cases; however, overestimation of the incidence may have occurred. This syndrome should be confirmed by serial intracompartmental pressure monitoring instead of only physical examination, and a sufficient dose of antivenom should be given prior to surgical decompression.

  14. Japan’s National Interests in Taiwan

    Science.gov (United States)

    2013-06-01

    Taiwan Relations:” “Trends in J-Pop [Japanese popular music] music, fashion, fast food, television soap operas, movies , karaoke, computer games, books...branch under the mandate of the TRA. This placement serves at least two functions: it keeps an extremely sensitive international issue in the scales of...competition with Japan in Taiwanese markets, basic economic interests between Taiwan, Japan, and the U.S. achieve a symbiosis of sorts, with top- brand

  15. Revision of Rubus (Rosaceae in Taiwan

    Directory of Open Access Journals (Sweden)

    Juinn-Yih Huang

    2009-11-01

    Full Text Available The genus Rubus L. in Taiwan is taxonomically revised based on morphological and phytogeographical patterns. Forty taxa (34 species, 3 varieties, and 3 hybrids of the genus are recognized, including two new hybrid species R. croceacanthus × corchorifolius and R. rosifolius × fraxinifolius. Among the Rubus taxa in Taiwan, R. croceacanthus H. Lév. exhibits tremendous variation and we do believe that more investigations are needed in the future. Several taxa described in the Flora of Taiwan, 2nd ed. are treated as synonyms of other species, and several taxa in Taiwan are revised. The existence of R. howii Merr. & Chun, R. linearifoliolus Hayata, and R. parvifraxinifolius Hayata in Taiwan are reconfirmed, we described R. howii fruit information which was absent in original literature; and the third taxon is treated as a natural hydrid R. × parvifraxinifolius Hayata which putatively derived from R. rosifolius Sm. and R. linearifoliolus based on intermediate morphology and the scarcity of fruit set. Rubus pseudoacer Makino ssp. flexuosus (Y.-C. Liu & F.-Y. Lu H. Ohashi & C.-F. Hsieh is treated as synonym of R. pseudoacer Makino and is excluded in Taiwan. A key to the taxa, synonyms and taxonomic descriptions of each taxon are presented. Moreover, information about phenology, chromosome number, distribution and specimens examined for each taxon are also provided.

  16. Decadal Oscillation of Fall Temperature in Taiwan

    Directory of Open Access Journals (Sweden)

    Jau-Ming Chen

    2008-01-01

    Full Text Available This study verifies the existence of an evident decadal oscillation in fall (September - November temperature for Taiwan. It has an island-wide spatial pattern and a central frequency of 11 years. Acorresponding decadal-oscillation mode of tropical sea surface temperature (SST is found to be largely responsible for inducing the decadal temperature oscillation for Taiwan via the following regulating processes. On a decadal timescale, periods of decadal warming in Taiwan concur with major cold anomalies in tropical SST over the eastern Indian Ocean and the central Pacific. These cold SST anomalies modulate tropical Walker circulation so as to produce anomalous descending centers in their regions. Meanwhile, the complementary anomalous ascending motion and anomalous low-level convergence center occur near the Maritime continent. These anomalous ascending and descending centers act as tropical forcing sources to evoke a low-level Rossby-wave-like circulation anomaly in the Asian-Pacific regions. Taiwan is surrounded by a low-level anomalous high to its east and an anomalous low to its west. These circulations induce anomalous flows from the south to warm Taiwan via anomalous warm advection. The above regulating processes reverse in polarity during periods of decadal cooling in Taiwan.

  17. Phylogenetic Classification of Seed Plants of Taiwan.

    Science.gov (United States)

    Lin, Cheng-Tao; Chung, Kuo-Fang

    2017-11-21

    Biological classification, the hierarchical arrangement of scientific names of organisms, constitutes the core infrastructure of biological databases. For an efficient management of biological databases, adopting a stable and universal biological classification system is crucial. Currently in Taiwan Biodiversity Information Facility (TaiBIF; http://taibif.tw/ ), the national portal website that integrates Taiwan's biodiversity information databases, angiosperms are arranged according to Cronquist's System of Classification, which is not compatible with current trend of the Angiosperm Phylogeny Group (APG) classification. To consolidate the function and management of the database, TaiBIF is moving to adopt the APG IV classification and Christenhusz et al. (Phytotaxa 19:55-70, 2011)'s classification of gymnosperms, which we summarize as the Phylogenetic Classification of Seed Plants of Taiwan. The Phylogenetic Classification of Seed Plants of Taiwan places gymnosperms in five families [vs. eight families in the Flora of Taiwan (FOT)] and angiosperms in 210 families (vs. 193 families in FOT). Three FOT gymnosperm families are synonymized in current treatment. Of the 210 APG IV families, familial circumscriptions of 114 families are identical with FOT and 50 families are recircumscription of FOT, with 46 families newly added. Of the 29 FOT families not included in current classification, two families are excluded and 27 families are synonymized. The adoption of the Phylogenetic Classification of Seed Plants of Taiwan in TaiBIF will provide better service and efficient management of the nation's biodiversity information databases.

  18. Women Scientists in Taiwan: An Update

    Directory of Open Access Journals (Sweden)

    Hsiu-Yun Wang

    2010-06-01

    Full Text Available This paper reflects upon issues of gender and science in Taiwan. Its starting point is the first academic paper on the subject published in Taiwan in 1996 by Fu and Wang, and then it draws upon the biographical accounts of 20 women scientists. We emphasize the importance of focusing on the specific contexts of the history of science and women in Taiwan. Partly as a result of Taiwan's colonial past and women's limited access to education, women scientists did not emerge in Taiwan until the second half of the 20th century when higher education became available to women. The gender issues with which women scientists in Taiwan have had to cope include the ways in which women have been excluded or included, their marital and career status, the local and global politics of scientific knowledge, and negotiating social networks. These issues have remained largely the same since the Fu and Wang study, but they have certainly gained wider attention and understanding, and greater articulation, both within academia and society.

  19. Occupational stress in submariners: the impact of isolated and confined work on psychological well-being.

    Science.gov (United States)

    Brasher, Kate S; Dew, Angela B C; Kilminster, Shaun G; Bridger, Robert S

    2010-03-01

    This study aimed to identify work-related and personal factors associated with occupational stress in submariners. Work and well-being questionnaires were distributed to 219 male submariners (mean age 34 years), as part of a larger cohort study involving a stratified sample of 4951 Royal Navy (RN) personnel. The stress rate in submariners was 40%; significantly higher than the stress rate in the general RN, although once demographic factors were controlled for in a matched control sample, this difference was no longer significant. A summary model accounted for 49% of the variance in submariner stress, with key differences emerging between the occupational factors associated with stress in submariners and in the general RN. The longitudinal nature of this study permits stress in submariners to be monitored over 5 years, which will provide valuable insights into the chronicity of stress in this specialised occupational group. STATEMENT OF RELEVANCE: This paper contributes to the current literature on the negative impact of working in isolated conditions. It is demonstrated that occupational stress in submarines can be partially explained using current theories of stress in the workplace. However, the constraints of a restricted environment introduce additional factors which can also be associated with occupational stress.

  20. Measuring currents in submarine canyons: technological and scientific progress in the past 30 years

    Science.gov (United States)

    Xu, J. P.

    2011-01-01

    The development and application of acoustic and optical technologies and of accurate positioning systems in the past 30 years have opened new frontiers in the submarine canyon research communities. This paper reviews several key advancements in both technology and science in the field of currents in submarine canyons since the1979 publication of Currents in Submarine Canyons and Other Sea Valleys by Francis Shepard and colleagues. Precise placements of high-resolution, high-frequency instruments have not only allowed researchers to collect new data that are essential for advancing and generalizing theories governing the canyon currents, but have also revealed new natural phenomena that challenge the understandings of the theorists and experimenters in their predictions of submarine canyon flow fields. Baroclinic motions at tidal frequencies, found to be intensified both up canyon and toward the canyon floor, dominate the flow field and control the sediment transport processes in submarine canyons. Turbidity currents are found to frequently occur in active submarine canyons such as Monterey Canyon. These turbidity currents have maximum speeds of nearly 200 cm/s, much smaller than the speeds of turbidity currents in geological time, but still very destructive. In addition to traditional Eulerian measurements, Lagrangian flow data are essential in quantifying water and sediment transport in submarine canyons. A concerted experiment with multiple monitoring stations along the canyon axis and on nearby shelves is required to characterize the storm-trigger mechanism for turbidity currents.

  1. Understanding temporal and spatial migration of orogenic magmatism: A numerical modelling approach

    Science.gov (United States)

    Andric, Nevena; Vogt, Katharina; Matenco, Liviu; Cvetkovic, Vladica; Cloetingh, Sierd; Gerya, Taras

    2017-04-01

    Magmatism occurs at all stages of orogenesis, i.e. oceanic subduction, continental subduction, and orogenic collapse. During these stages, magmatism varies in terms of volume, composition, spatial extent and temporal distribution, but the apparent causes and mechanisms of these changes still remain unsolved. Therefore, we have conducted a series of 2-D petrological-thermomechanical numerical experiments on oceanic subduction and subsequent collision to study the link between lithospheric scale processes and orogenic magmatism. Our results show that the resulting magmatic arc may have been built of magmatic rocks of distinct chemical characteristics and spatial distributions, depending on the crustal rheology, the thermal age of the oceanic lithosphere, the width of the ocean and the convergence rate. Although most models reveal a movement of the magmatic front towards the lower plate, subduction of very young oceanic lithosphere or collision of strong continents inhibits migration, i.e. the magmatic arc remains fixed during the whole model evolution. Despite temporal and spatial migration patterns of the magmatic front the studied experiments also display compositional changes, i.e. variations of the magmatic source. The dominant magmatic source varies during orogenesis from ultramafic (wet peridotite) to hybrid (wet peridotite, tectonic mélange and lower continental crust) and finally felsic (crustal material). Our numerical experiments yield new insights into the coupling between magmatism and lithospheric scale processes in the Dinarides Mountains of the Central Europe.

  2. Ediacaran 2,500-km-long synchronous deep continental subduction in the West Gondwana Orogen.

    Science.gov (United States)

    Ganade de Araujo, Carlos E; Rubatto, Daniela; Hermann, Joerg; Cordani, Umberto G; Caby, Renaud; Basei, Miguel A S

    2014-10-16

    The deeply eroded West Gondwana Orogen is a major continental collision zone that exposes numerous occurrences of deeply subducted rocks, such as eclogites. The position of these eclogites marks the suture zone between colliding cratons, and the age of metamorphism constrains the transition from subduction-dominated tectonics to continental collision and mountain building. Here we investigate the metamorphic conditions and age of high-pressure and ultrahigh-pressure eclogites from Mali, Togo and NE-Brazil and demonstrate that continental subduction occurred within 20 million years over at least a 2,500-km-long section of the orogen during the Ediacaran. We consider this to be the earliest evidence of large-scale deep-continental subduction and consequent appearance of Himalayan-scale mountains in the geological record. The rise and subsequent erosion of such mountains in the Late Ediacaran is perfectly timed to deliver sediments and nutrients that are thought to have been necessary for the subsequent evolution of sustainable life on Earth.

  3. Nappes, STEPs and the depth-dependence of orogenic arc formation

    Science.gov (United States)

    Wortel, Rinus; Govers, Rob; Polonia, Alina

    2017-04-01

    In spite of the classical nature of the subject, our understanding of nappe emplacement and the role of nappes in orogenic arc formation is still far from complete. We propose this stems from a lack of attention for the deeper, sub-crustal levels of the arc formation process. In this study we place the subject into a lithospheric scale perspective. Recent results concerning the present-day deformation of the Calabrian accretionary wedge and the underlying basement in the central Mediterranean (Polonia et al., Tectonophysics, 2016) provide an excellent starting point for exploring the role of lithospheric-scale tear faults near edges of subducting slabs (STEPs, Govers and Wortel, EPSL, 2005) in nappe emplacement and orogenic arc formation. Analysis of the Calabria-Sicily region leads us to propose a depth-dependent model for arc formation which distinguishes the near-surface nappes in the upper crustal depth range from the plate boundary evolution - through STEP activity - at the lithospheric scale, which dominates the deeper part. This new perspective accounts for several hitherto puzzling features of arc formation, in the Alpine-Mediterranean region (Alps, Apennines, Carpathians, Anatolia) and elsewhere, such as strongly variable nappe emplacement directions and the formation of very tightly curved arcs and series of juxtaposed arc-shaped thrust fronts. A likely setting of the proposed process is that of a region in a terminal stage of convergence, with (nearby) imminent continental or arc-continent collision.

  4. Prediction of nuclear submariner adaptability from autonomic indices and Rorschach Inkblot responses. Interim report

    Energy Technology Data Exchange (ETDEWEB)

    Weybrew, B.B.; Molish, H.B.

    1986-09-09

    To identify the most valid predictors of submariner adaptability, the authors derived 23 indices from the responses of 170 nuclear submariners to the Rorschach Inkblot Test, 11 measures of Autonomic Nervous System (ANS) reactivity to contrived stress, and five adjustment criteria. Factor analysis of this 39x39 correlation matrix yielded two Rorschach Factors, one of which correlated with three criterion dimensions. Two unique factors were also discovered, one, a structured ANS factor, and the other, a complex criterion scale. Selected Rorschach scores and, to a lesser extent, certain ANS indices emanating from this study, may be usefully-valid predictors of the adaptability of nuclear submariners during long patrols.

  5. MESO-NEOPROTEROZOIC GRENVILLE-SVECONORWEGIAN INTRACONTINENTAL OROGEN: HISTORY, TECTONICS, GEODYNAMICS

    Directory of Open Access Journals (Sweden)

    M. V. Mints

    2017-01-01

    Full Text Available The objective of this paper is to represent the main features inherent to Grenville-Sveconorwegian Orogen (GSNO and to propose a model of tectonic and geodynamic evolution of this orogen based on the results of research concerning similar Precambrian tectonic units in the East European Craton. The studies of the conditions and settings related to origin and evolution of GSNO are of special interest, because it is located geographicaly and in a certain sense ideologically in the center of Rodinia, a supposed Neoproterozoic supercontinent. GSNO originated in the MezoNeoproterozoic in the inner region of the Lauroscandia continent. At present, the synformal tectonic structure of GSNO is divided into two portions: Grenville sector along the southeastern margin of the Canadian Shield, and Sveconorwegian sector in the southwestern Scandinavia. The integrity of Lauroscandia was twice disturbed in the MezoNeoproterozoic when oceanic structures resembling the Atlantic Ocean were formed. Later on, the continuity of the continent was restored with the involvement of oceanic lithosphere subduction and accretion and obduction of the island-arc and oceanic terranes. We distinguish two stages in the GSNO history: (1 ‘preparatory’ stage (from ~1.90 to ~1.16 Ga, and (2 formation of GSNO proper (from ~1.19 to ~0.90 Ga. The manifestations of granulite-facies metamorphism were repeatedly recorded before the Grenville Orogeny at 1.67–1.66, 1.47–1.45, 1.37–1.35, and 1.20–1.18 Ga. The Ottawan stage of the Grenville metamorphism proper is dated between 1.16 and 1.05–1.03 Ga. Metamorphism at the base of Allochthonous Belt corresponds to high-pressure granulite facies and, in a number of places, to hightemperature eclogite facies (800–900 °C at pressure in the range between 14 and 20 kbar. The age of metamorphism of rocks within Paraautochthonous Belt is 1.05–0.95 Ga; metamorphic grade increases from the greenschist facies near the Grenville front to

  6. Cenozoic landforms and post-orogenic landscape evolution of the Balkanide orogen: Evidence for alternatives to the tectonic denudation narrative in southern Bulgaria

    Science.gov (United States)

    Gunnell, Y.; Calvet, M.; Meyer, B.; Pinna-Jamme, R.; Bour, I.; Gautheron, C.; Carter, A.; Dimitrov, D.

    2017-01-01

    Continental denudation is the mass transfer of rock from source areas to sedimentary depocentres, and is typically the result of Earth surface processes. However, a process known as tectonic denudation is also understood to expose deep-seated rocks in short periods of geological time by displacing large masses of continental crust along shallow-angle faults, and without requiring major contributions from surface erosion. Some parts of the world, such as the Basin and Range in the USA or the Aegean province in Europe, have been showcased for their Cenozoic tectonic denudation features, commonly described as metamorphic core-complexes or as supradetachment faults. Based on 22 new apatite fission-track (AFT) and 21 helium (AHe) cooling ages among rock samples collected widely from plateau summits and their adjacent valley floors, and elaborating on inconsistencies between the regional stratigraphic, topographic and denudational records, this study frames a revised perspective on the prevailing tectonic denudation narrative for southern Bulgaria. We conclude that conspicuous landforms in this region, such as erosion surfaces on basement-cored mountain ranges, are not primarily the result of Paleogene to Neogene core-complex formation. They result instead from "ordinary" erosion-driven, subaerial denudation. Rock cooling, each time suggesting at least 2 km of crustal denudation, has exposed shallow Paleogene granitic plutons and documents a 3-stage wave of erosional denudation which progressed from north to south during the Middle Eocene, Oligocene, Early to Middle Miocene, and Late Miocene. Denudation initially prevailed during the Paleogene under a syn-orogenic compressional regime involving piggyback extensional basins (Phase 1), but subsequently migrated southward in response to post-orogenic upper-plate extension driven by trench rollback of the Hellenic subduction slab (Phase 2). Rare insight given by the denudation pattern indicates that trench rollback

  7. Marine litter in submarine canyons of the Bay of Biscay

    Science.gov (United States)

    van den Beld, Inge M. J.; Guillaumont, Brigitte; Menot, Lénaïck; Bayle, Christophe; Arnaud-Haond, Sophie; Bourillet, Jean-François

    2017-11-01

    Marine litter is a matter of increasing concern worldwide, from shallow seas to the open ocean and from beaches to the deep-seafloor. Indeed, the deep sea may be the ultimate repository of a large proportion of litter in the ocean. We used footage acquired with a Remotely Operated Vehicle (ROV) and a towed camera to investigate the distribution and composition of litter in the submarine canyons of the Bay of Biscay. This bay contains many submarine canyons housing Vulnerable Marine Ecosystems (VMEs) such as scleractinian coral habitats. VMEs are considered to be important for fish and they increase the local biodiversity. The objectives of the study were to investigate and discuss: (i) litter density, (ii) the principal sources of litter, (iii) the influence of environmental factors on the distribution of litter, and (iv) the impact of litter on benthic communities. Litter was found in all 15 canyons and at three sites on the edge of the continental shelf/canyon, in 25 of 29 dives. The Belle-île and Arcachon Canyons contained the largest amounts of litter, up to 12.6 and 9.5 items per 100 images respectively. Plastic items were the most abundant (42%), followed by fishing-related items (16%). The litter had both a maritime and a terrestrial origin. The main sources could be linked to fishing activities, major shipping lanes and river discharges. Litter appeared to accumulate at water depths of 801-1100 m and 1401-1700 m. In the deeper of these two depth ranges, litter accumulated on a geologically structured area, accounting for its high frequency at this depth. A larger number of images taken in areas of coral in the shallower of these two depth ranges may account for the high frequency of litter detection at this depth. A larger number of litter items, including plastic objects in particular, were observed on geological structures and in coral areas than on areas of bare substratum. The distribution of fishing-related items was similar for the various types of

  8. Particle sedimentation and diffusive convection in submarine clouds

    Science.gov (United States)

    Carazzo, G.; Jellinek, M.; Turchyn, A. V.

    2013-12-01

    The longevity of submarine plumes generated by the release of hydrothermal fluids during crustal rupturing or by the rapid cooling of an erupting lava flow constrains the input of crustal-derived elements into the deep-ocean. Decades of observations of episodic "event plumes" suggest that a key process governing the dynamics of a submarine cloud spreading out laterally from a buoyant rising plume is the production of internal layering. Here, we use geological data on submarine clouds and a new experimental apparatus producing at laboratory scale turbulent, hot particle-laden plumes and clouds to show that this layering occurs where particle diffusive convection driven by the differential diffusion of heat and small mineral precipitates gives rise to a large scale double diffusive instability. We show that this "particle diffusive convection" can extend the longevity of an event plume to two years after its emplacement, allowing iron-sulfide minerals to dissolve and deliver iron to the deep-ocean. The very long residence time imposed by diffusive convective effects does not allow iron-oxide minerals to dissolve but may lead to the formation of iron-rich sediments at large distances from the point of emission. We develop a new theoretical model that includes both sedimentation and dissolution processes to quantify the potential amount of iron produced by the dissolution of iron-sulfide minerals settling through the cloud by diffusive convection. A key prediction is that hydrothermal systems could provide 75% of the global budget of dissolved iron in the deep-ocean. The consideration of scale-basin variations suggests that the Southern Hemisphere is probably the most impacted by hydrothermal iron, consistent with observations and global ocean models. Photographs showing the typical evolution of a lab-scale turbulent, hot particle-laden plume. At stage 1, the buoyant plume reaches a level of neutral buoyancy and spreads out laterally forming a neutrally buoyant cloud

  9. Hawaiian submarine manganese-iron oxide crusts - A dating tool?

    Science.gov (United States)

    Moore, J.G.; Clague, D.A.

    2004-01-01

    Black manganese-iron oxide crusts form on most exposed rock on the ocean floor. Such crusts are well developed on the steep lava slopes of the Hawaiian Ridge and have been sampled during dredging and submersible dives. The crusts also occur on fragments detached from bedrock by mass wasting, on submerged coral reefs, and on poorly lithified sedimentary rocks. The thickness of the crusts was measured on samples collected since 1965 on the Hawaiian Ridge from 140 dive or dredge localities. Fifty-nine (42%) of the sites were collected in 2001 by remotely operated vehicles (ROVs). The thinner crusts on many samples apparently result from post-depositional breakage, landsliding, and intermittent burial of outcrops by sediment. The maximum crust thickness was selected from each dredge or dive site to best represent crusts on the original rock surface at that site. The measurements show an irregular progressive thickening of the crusts toward the northwest-i.e., progressive thickening toward the older volcanic features with increasing distance from the Hawaiian hotspot. Comparison of the maximum crust thickness with radiometric ages of related subaerial features supports previous studies that indicate a crust-growth rate of about 2.5 mm/m.y. The thickness information not only allows a comparison of the relative exposure ages of two or more features offshore from different volcanoes, but also provides specific age estimates of volcanic and landslide deposits. The data indicate that some of the landslide blocks within the south Kona landslide are the oldest exposed rock on Mauna Loa, Kilauea, or Loihi volcanoes. Crusts on the floors of submarine canyons off Kohala and East Molokai volcanoes indicate that these canyons are no longer serving as channelways for downslope, sediment-laden currents. Mahukona volcano was approximately synchronous with Hilo Ridge, both being younger than Hana Ridge. The Nuuanu landslide is considerably older than the Wailau landslide. The Waianae

  10. Newly recognized submarine slide complexes in the southern California Bight

    Science.gov (United States)

    Conrad, J. E.; Lee, H. J.; Edwards, B. D.; McGann, M.; Sliter, R. W.

    2012-12-01

    New high-resolution bathymetric and seismic-reflection surveys have imaged large (7) individual overlapping slides along the western margin of Santa Cruz Basin (SCB slide); 2) a series of slumps and slide scars on the slope south of San Pedro shelf (SPS slide); and 3) a slope failure along the shelf edge in northern San Diego County, termed the Del Mar slide. The SCB slide complex extends for 30 km along the western slope of Santa Cruz Basin, with debris lobes extending 5-8 km into the basin. Head scarps of some of these slides are 50-75 m high. The SPS slide complex also appears to consist of multiple slides, which roughly parallel the Palos Verdes Fault and the San Gabriel Canyon submarine channel on the shelf edge and slope south of San Pedro shelf. Slide deposits associated with this complex are only partially mapped due to limited high-resolution bathymetric coverage, but extend to the south in the area SW of Lasuen Knoll. Seismic-reflection profiles show that some of these deposits are up to 20 m thick. The Del Mar slide is located about 10 km north of La Jolla Canyon and extends about 6 km along the shelf edge. The head scarp lies along the trend of a branch of the Rose Canyon Fault Zone. Radiocarbon ages of sediment overlying this slide indicate the Del Mar slide is approximately 12-16 ka. These large slide complexes have several characteristics in common. Nearly all occur in areas of tectonic uplift. All of the complexes show evidence of recurrent slide activity, exhibiting multiple headwall scarps and debris lobes, and where available, high-resolution seismic-reflection profiles of these slide areas provide evidence of older, buried mass transport deposits. Assuming typical sedimentation rates, the recurrence interval of major slide events appears to be on the order of tens of thousands of years. Most of the slide complexes do not appear to be located in areas of high sediment input. The SCB and Del Mar slides are in areas receiving relatively small

  11. Simulation of Climate Control On Tectonic Mass-transfer In Bivergent Orogenic Wedges ­ Insights From Scaled Sandbox Models.

    Science.gov (United States)

    Hoth, S.; Adam, J.; Kukowski, N.; Oncken, O.

    Orogenic wedges are expressions of dynamic equilibrium between tectonic and grav- itational stresses. Thus, surficial mass transport by climate-driven erosion changes the morphology of, and the state of stress within, the orogenic wedge. Here, we suggest that the orogenic wedge adjusts itself to the new stress conditions, inducing changes in morphology, which may modify the pre-existing drainage pattern, and therefore change also the erosion rate. Depending on the amount of vertical alteration in wedge morphology the regional climate is modified, which again may lead to a different ero- sion rate. The aim of this study is to describe qualitatively and quantitatively how different ero- sion rates and their 2D lateral distribution influences the mass-transport mode in col- lisional orogens, using scaled sandbox-experiments. The advantages of analogue sim- ulation are (i) a more detailed structural resolution, (ii) a direct observation of strain localisation and fault propagation and (iii) an easy way of applying erosion at any given point through time. The models presented here were run in a 2D shearbox with two converging sand lay- ers which build up a bivergent sand-orogen. A thin glass-bead layer which simulates a mid-level detachment was incorporated to allow frontal and basal accretion. Us- ing a vacuum cleaner, incremental erosion, which decreases linearly from the top of the sand-orogen to the toe of either the pro-wedge or retro-wedge, was simulated. A friction-controlled elastic/plastic rheology with strain hardening and softening is used to simulate upper crustal rock deformation. Our aim is to elucidate: (i) The in- fluence of different modes of distribution of erosion rates on the tectonically-driven mass transfer in orogenic belts. (ii) The control of erosion rates on tectonic style in orogenic wedges, i.e. frontal versus basal accretion. (iii) The time and length scales at which climatic and tectonic forces interact. (iv) The way with which such

  12. H/V spectral ratios of the continental margin sediments offshore southwestern Taiwan

    Science.gov (United States)

    Lin, Jing-Yi; Cheng, Win-Bin; Chin, Shao-Jinn; Hsu, Shu-Kun

    2015-04-01

    For decades, it has been mentioned that submarine slope failures are spatially linked to the presence of gas hydrates/gas-charged sediments. When triggered by earthquakes, over steepen and instable sediments may prompt breakouts of the slopes containing gas hydrates and cause submarine landslides and tsunamis. Widely distributed BSRs have been observed in the area offshore of southwestern Taiwan where the active accretionary complex meets with the passive China continental margin. In the region, large or small scale landslides were also reported based on seismic interpretations. In order to clarify the link between earthquake, landslide and the presence of gas hydrate, we evaluate the response of seafloor sediments in regard to passive dynamic loads. Horizontal-to-vertical (H/V) spectral ratios are used to characterize the local sediment response. Ambient noise as well as distant earthquake is used as generators of the passive dynamic loads. Based on this study, we aim to characterize the site in terms of its physical properties and the local site effect produced by shallow marine sediments. Estimating H/V spectral ratios of data recorded by the short period OBSs (Ocean Bottom Seismometer) deployed in the active and paqssive margin offshore southwestern Taiwan show similar spectral characteristics and provide a general understanding of the preferential vibration modes of sediment systems. The results show that the maximal H/V ratios appeared in the range of 5-10 Hz, where the horizontal amplitudes increased by an order of magnitude relative to the vertical amplitude. The stations located in the northwestern part of study area were characterized by another relatively small peak at proximately 2 Hz, which may indicates the presence of a discontinuity of sediments. For most stations, the H/V ratios estimated based on the earthquakes (i.e. strong input signal) and noise (background, micro-seismic noise) records were characterized by different pattern. No distinct peak

  13. Factors associated with Taiwan anesthesiologists' intention to leave anesthesia practice

    Directory of Open Access Journals (Sweden)

    Ju-O Wang

    2015-06-01

    Conclusion: Unfavorable working conditions were considered to lower the satisfaction of anesthesiologists in Taiwan. In particular, an inability to take care of the family and a low salary were major factors in deterring anesthesiologists in Taiwan from continuing in anesthesia.

  14. Taiwan: Recent Developments and U.S. Policy Choices

    National Research Council Canada - National Science Library

    Dumbaugh, Kerry

    2006-01-01

    .... Among other things, President Bush publicly stated in 2001 that the United States would do "whatever it takes" to help Taiwan's defense and approved, in April 2001, a substantial sale of U.S. weapons to Taiwan...

  15. Multi-scale evaluations of submarine groundwater discharge

    Directory of Open Access Journals (Sweden)

    M. Taniguchi

    2015-03-01

    Full Text Available Multi-scale evaluations of submarine groundwater discharge (SGD have been made in Saijo, Ehime Prefecture, Shikoku Island, Japan, by using seepage meters for point scale, 222Rn tracer for point and coastal scales, and a numerical groundwater model (SEAWAT for coastal and basin scales. Daily basis temporal changes in SGD are evaluated by continuous seepage meter and 222Rn mooring measurements, and depend on sea level changes. Spatial evaluations of SGD were also made by 222Rn along the coast in July 2010 and November 2011. The area with larger 222Rn concentration during both seasons agreed well with the area with larger SGD calculated by 3D groundwater numerical simulations.

  16. Risk assessment in submarine outfall projects: the case of Portugal.

    Science.gov (United States)

    Mendonça, Ana; Losada, Miguel Ángel; Reis, Maria Teresa; Neves, Maria Graça

    2013-02-15

    Submarine outfalls need to be evaluated as part of an integrated environmental protection system for coastal areas. Although outfalls are tight with the diversity of economic activities along a densely populated coastline being effluent treatment and effluent reuse a sign of economic prosperity, precautions must be taken in the construction of these structures. They must be designed so as to have the least possible impact on the environment and at the same time be economically viable. This paper outlines the initial phases of a risk assessment procedure for submarine outfall projects. This approach includes a cost-benefit analysis in which risks are systematically minimized or eliminated. The methods used in this study also allow for randomness and uncertainty. The input for the analysis is a wide range of information and data concerning the failure probability of outfalls and the consequences of an operational stoppage or failure. As part of this risk assessment, target design levels of reliability, functionality, and operationality were defined for the outfalls. These levels were based on an inventory of risks associated with such construction projects, and thus afforded the possibility of identifying possible failure modes. This assessment procedure was then applied to four case studies in Portugal. The results obtained were the values concerning the useful life of the outfalls at the four sites and their joint probability of failure against the principal failure modes assigned to ultimate and serviceability limit states. Also defined were the minimum operationality of these outfalls, the average number of admissible technical breakdowns, and the maximum allowed duration of a stoppage mode. It was found that these values were in consonance with the nature of the effluent (tourist-related, industrial, or mixed) as well as its importance for the local economy. Even more important, this risk assessment procedure was able to measure the impact of the outfalls on

  17. Imaging deformation in submarine thrust belts using seismic attributes

    Science.gov (United States)

    Iacopini, David; Butler, Robert W. H.

    2011-02-01

    Uncertainty exists as to the patterns of deformation that develop within submarine thrust belts. This case study uses a large-scale gravity-driven fold-thrust structure as an analogue for submarine fold thrust systems in general. Seismic attribute analysis and mapping provide ways of identifying complex fault patterns and associated deformation that are otherwise unresolved in conventional amplitude displays. These methods are developed and applied to a 3D dataset and used to investigate the geometry, internal architecture and the nature of the low signal/noise incoherency and discontinuities observed on the km-scale. Semblance (coherency), curvatures and spectral decomposition were all computed and used as attributes. Collectively these define volumes within the seismic data where the signal is greatly reduced — features termed here "disturbance geobodies". The study shows that thrust faults that, on conventional amplitude displays appear to be simple and continuous, are likely to consist of complex arrays of anastamosing fault strands. Adjacent to these composite fault zones are greater volumes of deformed rocks (disturbance geobodies) across which there are only minor stratal offsets. Similarly volumes of high stratal curvature coincide with disturbance geobodies, again interpreted as zones of weak, distributed deformation. These relationships between narrow thrust faults and broader zones of deformation are broadly comparable to those observed in outcrops within exhumed thrust systems. Application of the seismic imaging techniques developed here will improve the understanding of the localization of deformation in sedimentary successions with important implications for predicting fluid flow within other deep water structures such as subduction accretion complexes.

  18. Geo-hazard by sediment mass movements in submarine canyons

    Science.gov (United States)

    Ghaith, Afif; Fakhri, Milad; Ivaldi, Roberta; Ciavola, Paolo

    2017-04-01

    Submarine mass movements and their consequences are of major concern for coastal communities and infrastructures but also for the exploitation and the development of seafloor resources. Elevated awareness of the need for better understanding of the underwater mass movement is coupled with great advances in underwater mapping technologies over the past two decades. The seafloor in the Nahr Ibrahim and Saida regions (Lebanon) is characterized by deep canyons, reaching one thousand meters depths in proximity of the coast. Signs of submarine mass movement instability related to these canyons create a connection between shallow and deep water. The presence of these canyons in a tectonically active area generates a particular drained mechanism to the sediment in form of mass movement and slumping. Identification of potential areas where slope movements could be triggered requires data with high spatial resolution. Since this area is poorly explored, in the framework of an international project between Lebanese Navy, Lebanese National Center for Marine Sciences, University of Ferrara and Italian Hydrographic Institute, we analyse the morpho-bathymetric and sedimentological characters of the coastal and shelf sectors. Multibeam echosounder and sub-bottom profiler acoustic systems calibrated with ground truths (sediment grab and core samples) allow us to characterize the nature of seafloor and sub-seafloor with particular detail to the geotechnical properties of sediments and high resolution seismic stratigraphy of the shallow layers. The detection of particular undersea features provides detail maps which are in support to littoral morpho-dynamics, coastal transport and sediment budget. Multilayer hydro-oceanographic map, referring to the seafloor dynamics in connection with deep water environment and drainage system, in accordance to the International Hydrographic Standards and nautical supports, are produced. This high resolution multibeam bathymetry dataset, integrated

  19. New Evidence of Regional Geological Structures Inferred from Reprocessing and Resistivity Data Interpretation in the Chingshui-Sanshing-Hanchi Area of Southwestern Ilan County, NE Taiwan

    Directory of Open Access Journals (Sweden)

    Gong-Ruei Ho

    2014-01-01

    Full Text Available The Ilan Plain is located at the southwestern tip of the back arc basin of the Okinawa Trough, which propagates westward into the Taiwan orogen. A long discussed issue concerns whether the opening normal-fault system of the Okinawa Trough propagates and transforms into the thrust-fault system of the Taiwan orogen. We have reprocessed and inverted resistivity measurements from a series of surveys conducted in the 1970s around the Chingshui-Sanshing-Hanchi area of southwestern Ilan County. The 2D and 3D inverted resistivity images reveal the regional structures. A major conductive structure dipping toward the northwest at an angle of 30° - 40° is located at the expected site of the Niudou Fault separating the Early Miocene Szeleng and Kangkou Formations from the Lushan Formation in the Sanshing area, which dip direction of two conductive structures with a dipping angle of 50° - 70° were coinciding with the dip direction of normal faults identified from the field surveys. In addition three high-angle discontinuity structures, dipping toward the north with an angle of 60° - 80° can be identified in the resistivity profile along Hanchi. We tend to suggest these structures as the extended portions of the normal faults that have been identified under the unconsolidated sediments in the Ilan Plain. Resistivity profiles from the Chingshuichi area reveal the existence of the vertical Chingshuichi, the Dachi, and the Xiaonanauo Fault. Hot springs were found in the junction area of the Chingshuichi and the Xiaonanauo Fault. The junction region of these two fault systems is the potential Chingshui geothermal field that provides fluid geothermals from the deep.

  20. Did a "lucky shot" sink the submarine H.L. Hunley?

    Science.gov (United States)

    Lance, Rachel M; Warder, Henry; Bass, Cameron R Dale

    2017-01-01

    The H.L. Hunley was the first submarine to be successful in combat, sinking the Union vessel Housatonic outside Charleston Harbor in 1864 during the Civil War. However, despite marking a milestone in military history, little is known about this vessel or why it sank. One popular theory is the "lucky shot" theory: the hypothesis that small arms fire from the crew of the Housatonic may have sufficiently damaged the submarine to sink it. However, ballistic experiments with cast iron samples, analysis of historical experiments firing Civil War-era projectiles at cast iron samples, and calculation of the tidal currents and sinking trajectory of the submarine indicate that this theory is not likely. Based on our results, the "lucky shot" theory does not explain the sinking of the world's first successful combat submarine. Published by Elsevier B.V.

  1. The impact of glacier geometry on meltwater plume structure and submarine melt in Greenland fjords

    NARCIS (Netherlands)

    Carroll, D.; Sutherland, D. A.; Hudson, B.; Moon, T.; Catania, G. A.; Shroyer, E. L.; Nash, J. D.; Bartholomaus, T. C.; Felikson, D.; Stearns, L. A.; Noël, B. P Y; van den Broeke, M. R.

    2016-01-01

    Meltwater from the Greenland Ice Sheet often drains subglacially into fjords, driving upwelling plumes at glacier termini. Ocean models and observations of submarine termini suggest that plumes enhance melt and undercutting, leading to calving and potential glacier destabilization. Here we

  2. An Analysis of the Effectiveness of a New Watchstanding Schedule for U.S. Submariners

    National Research Council Canada - National Science Library

    Osborn, Christopher

    2004-01-01

    A need exists within the U.S. submarine force to employ an operational schedule that provides more sleep and that is in better alignment with human circadian rhythms, thus improving cognitive effectiveness...

  3. Fuel cell systems for submarines: from the first idea to serial production

    Science.gov (United States)

    Psoma, Angela; Sattler, Gunter

    The future submarines of Howaldtswerke-Deutsche Werft AG (HDW) will be equipped with fuel cell power plants for air independent propulsion. In the 1970s the decision for a fuel cell system on submarines was made. Tests in the 1980s confirmed the feasibility of fuel cells on submarines. Positive development results in the 1990s led to series production of fuel cell equipped submarines, which will be in operation from 2003 onwards. Strictly controlled development work was necessary to reach the goal of series production. The train of thought behind this process of development is described in this paper starting with the initial idea and ending with the description of the serial production of the fuel cell power plant. The future outlook gives an impression of current development work.

  4. Submarine Warfare in the 20th & 21st Centuries: A Bibliography

    National Research Council Canada - National Science Library

    Huygen, Michaele

    2003-01-01

    There are constant motions in the sea caused by atmospheric and seabed activities volcanic disruptions marine animals ships and submarines -- all of which create what is called the ambient noise level of the oceans...

  5. The risk of hydrogen explosion in a submarine p. IV The implementation of high risk projects

    Directory of Open Access Journals (Sweden)

    Kłos Ryszard

    2017-06-01

    Full Text Available This series of articles on high risk projects looks at the example of the modernisation of hydrogen incinerators on a submarine. The article describes problems connected with the management of such a project.

  6. Volume transport data from a submarine cable in the Florida Strait in 2014 (NODC Accession 0125429)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Daily mean and raw voltage volume transport data of the Florida Current collected with a submarine cable spanning from South Florida to the Grand Bahama Island in...

  7. A Statistical Analysis of the Impact of Marital Status on Nuclear Submarine Officer Retention

    National Research Council Canada - National Science Library

    Phelps, Matthew

    2001-01-01

    This thesis develops multivariate logit models to estimate the impact of marital status and the independent effect of dependent children on nuclear submarine officer retention beyond the minimum service requirement (MSR...

  8. Observations of nearshore groundwater discharge: Kahekili Beach Park submarine springs, Maui, Hawaii

    Directory of Open Access Journals (Sweden)

    P.W. Swarzenski

    2017-06-01

    New hydrological insights for the region: Estimates of submarine groundwater discharge were derived for a primary vent site and surrounding coastal waters off west Maui, Hawaii using an excess 222Rn (t1/2 = 3.8 d mass balance model. Such estimates were complemented with a novel thoron (220Rn, t1/2 = 56 s groundwater discharge tracer application, as well as oceanographic time series and thermal infrared imagery analyses. In combination, this suite of techniques provides new insight into the connectivity of the coastal aquifer with the near-shore ocean and examines the physical drivers of submarine groundwater discharge. Lastly, submarine groundwater discharge derived constituent concentrations were tabulated and compared to surrounding seawater concentrations. Such work has implications for the management of coastal aquifers and downstream nearshore ecosystems that respond to sustained constituent loadings via this submarine route.

  9. Dance With the One That Brought You: Revitalizing Antisubmarine Warfare to Counter Chinese Diesel Submarines

    National Research Council Canada - National Science Library

    Farrell, Richard

    2003-01-01

    .... Navy needs to revitalize ASW, or risk losing the ability to gain sea control in strategic areas of the East Asian Littoral and South China Sea due to a rising Chinese diesel-electric submarine threat...

  10. Submarine Upward Looking Sonar Ice Draft Profile Data and Statistics, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set consists of upward looking sonar sea ice draft data collected by submarines in the Arctic Ocean. It includes data from both U.S. Navy and Royal Navy...

  11. Navy Trident Submarine Conversion (SSGN) Program: Background and Issues for Congress

    National Research Council Canada - National Science Library

    O'Rourke, Ronald

    2005-01-01

    ...) into cruisemissile- carrying and special operations forces (SOF) support submarines (SSGNs). The total estimated cost of the program, which has been increasing over time, is now $4,018 million...

  12. Management of scrap computer recycling in Taiwan.

    Science.gov (United States)

    Lee, C H; Chang, S L; Wang, K M; Wen, L C

    2000-04-28

    It is estimated that approximately 300,000 scrap personal computers are generated each year in Taiwan [S.-L. Chang, A Study on the Scrap Computer Treatment Cost, Environment Protection Administration of Taiwan, December 1998 (in Chinese)]. The disposal of such a huge number of scrap computers presents a difficult task for the island due to the scarcity of landfills and incineration facilities available locally. Also, the hazardous materials contained (i.e., phosphor coatings of cathode ray tubes (CRTs), batteries, polychlorinated biphenyl capacitors, mercury-containing parts, liquid crystal display, high-lead content CRT funnel glass, and plastic containing flame-retardant bromine, etc.) in the scrap computers may seriously pollute the environment if they are not properly disposed of. Therefore, the EPA of Taiwan declared scrap personal computers the producer's recycling responsibility as of July 1997. Under this decree, the manufacturers, importers and sellers of personal computers have to properly recover and recycle the scrapped computers which they originally sell. On June 1, 1998, a producer responsibility recycling program for scrap computers was officially implemented in Taiwan. Under this program, consumers can bring their unwanted personal computers to the designated collection points and receive reward money. Currently, only six computer items are mandated to be recycled in this recycling program. They are notebooks, monitors, hard disks, power supplies, printed circuit boards and main frame shells. This article outlines the current scrap computer recycling system in Taiwan.

  13. The Alps 2: Controls on crustal subduction and (ultra)high‐pressure rock exhumation in Alpine‐type orogens

    National Research Council Canada - National Science Library

    Butler, Jared P; Beaumont, Christopher; Jamieson, Rebecca A

    2014-01-01

    ...‐type orogens and the Alps per se, focusing on (ultra)high‐pressure ((U)HP) metamorphic rocks. The models show that UHP rocks form and exhume by burial and subsequent buoyant ascent of continental crust in the subduction conduit...

  14. An Event Study of Chinese Tourists to Taiwan

    NARCIS (Netherlands)

    C-L. Chang (Chia-Lin); S.-H. Hsu (Shu-Han); M.J. McAleer (Michael)

    2018-01-01

    markdownabstractThe number of Chinese tourists visiting Taiwan has been closely related to the political relationship across the Taiwan Strait. The occurrence of political events and disasters or accidents have had, and will continue to have, a huge impact on the Taiwan tourism market. To date,

  15. Memory contested, locality transformed : representing Japanese colonial 'heritage' in Taiwan

    NARCIS (Netherlands)

    Chiang, Min-Chin

    2012-01-01

    In the search for a Taiwanese identity rooted in the land of Taiwan the Japanese colonial past plays an ambiguous role. The Japanese colonial sites became a constituent part of the new identity and cultural narrative of Taiwan in the 1990s and 2000s, when a memory boom was experienced in Taiwan

  16. 75 FR 15726 - Polyvinyl Alcohol From Taiwan; Determination

    Science.gov (United States)

    2010-03-30

    ... COMMISSION Polyvinyl Alcohol From Taiwan; Determination On the basis of the record \\1\\ developed in the... Taiwan of polyvinyl alcohol provided for in subheading 3905.30.00 of the Harmonized Tariff Schedule of... threatened with material injury by reason of allegedly LTFV imports of polyvinyl alcohol from Taiwan...

  17. Tectonic processes during oblique collision: Insights from the St. Elias orogen, northern North American Cordillera

    Science.gov (United States)

    Pavlis, T.L.; Picornell, C.; Serpa, L.; Bruhn, R.L.; Plafker, G.

    2004-01-01

    Oblique convergence in the St. Elias orogen of southern Alaska and northwestern Canada has constructed the world's highest coastal mountain range and is the principal driver constructing all of the high topography in northern North America. The orogen originated when the Yakutat terrane was excised from the Cordilleran margin and was transported along margin-parallel strike-slip faults into the subduction-transform transition at the eastern end of the Aleutian trench. We examine the last 3 m.y. of this collision through an analysis of Euler poles for motion of the Yakutat microplate with respect to North America and the Pacific. This analysis indicates a Yakutat-Pacific pole near the present southern triple junction of the microplate and' predicts convergence to dextral-oblique convergence across the offshore Transition fault, onland structures adjacent to the Yakutat foreland, or both, with plate speeds increasing from 10 to 30 mm/yr from southeast to northwest. Reconstructions based on these poles show that NNW transport of the collided block into the NE trending subduction zone forced contraction of EW line elements as the collided block was driven into the subduction-transform transition. This suggests the collided block was constricted as it was driven into the transition. Constriction provides an explanation for observed vertical axis refolding of both earlier formed fold-thrust systems and the collisional suture at the top of the fold-thrust stack. We also suggest that this motion was partially accommodated by lateral extrusion of the western portion of the orogen toward the Aleutian trench. Important questions remain regarding which structures accommodated parts of this motion. The Transition fault may have accommodated much of the Yakutat-Pacific convergence on the basis of our analysis and previous interpretations of GPS-based geodetic data. Nonetheless, it is locally overlapped by up to 800 m of undeformed sediment, yet elsewhere shows evidence of young

  18. Kinematic modelling of neotectonics in the Persia-Tibet-Burma orogen

    Science.gov (United States)

    Liu, Zhen; Bird, Peter

    2008-02-01

    We apply a new kinematic modelling technique (program NeoKinema) to estimate neotectonic flow in the Persia-Tibet-Burma orogen. The models fit geodetic benchmark velocities, geological fault slip rates and stress directions (seismic moment tensor orientations) using a weighted-least-squares method. Models predict long-term velocities, anelastic strain rates and preferred fault slip rates averaged over timescales of 104-106 yr. While we find a few regions of low anelastic strain rate, the mean continuum strain rate in the preferred model is 2.2 × 10-16 s-1 (0.7 per cent Ma-1), so the India-Eurasia collision should not be modelled as an interaction between rigid microplates. For most faults, preferred fault slip rates agree with geological slip rates within their uncertainty bounds; this suggests that deformation imaged by geodesy over tens of years is consistent with deformation over 104-106 yr (given appropriate elastic corrections). We also calculate maps of long-term-average seismicity rate based on model fault slip rates and anelastic strain rates in the continuum, using the seismicity parameters of most comparable type of plate boundary. The pattern is generally in agreement with actual m > 5.67 earthquakes in the CMT catalogue (1977-2002), except that the Himalayan front, High Zagros and Altyn Tagh zones have been quieter than predicted. The spatial integral of our forecast over the orogen is 371 m > 5.67 earthquakes/25.75 yr, versus 238 which actually occurred. If this discrepancy has high significance, it means that some step(s) in our forecast method are faulty (such as the assumption of equal coupled seismogenic thickness in all continental convergent boundaries). If it is only an artefact of stochastic time-dependence, then this may have occurred in the orogen, in the external calibration region, or in both. Independent evidence suggests that large earthquakes (with many aftershocks) will occur along the Himalayan front in the future, possibly reducing

  19. Kinematic modeling of Neotectonic velocity field of the Persia-Tibet-Burma Orogen

    Science.gov (United States)

    Liu, Z.; Bird, P.

    2003-12-01

    New kinematic finite-element program NeoKinema has been applied to compute the long-term-average velocity field and fault slip rates in the Persia-Tibet-Burma orogen using the Maximum-likelihood criterion. The orogen extends from east Turkey on the west, to Burma and Laos on the south, to east and southeast China on the east, and to Mongolia on the north. We use three data sets in our modeling: 1497 GPS benchmark solutions compiled from published sources, 366 geologic slip rates with standard deviations, 876 most compressive horizontal principal stress directions from the World Stress Map 2003 [Mueller et al., 2003]. Faults and potentially active faults are included. But faults of less constrained slip rates, e.g., faults in Iran, are assigned with large uncertainty. An iterative procedure is used to correct for transient fault locking effects on geodetic data. We use an updated plate model PB2002 to approximate the velocity boundary conditions from surrounding rigid plates (Anatolia, Arabia, India, Burma, Sunda, Yangtze, Amur) and the rigid part of the Eurasia plate in a Eurasia-fixed reference frame [Bird, 2003]. We also test various Sunda-Eurasia Euler poles and their effects on our modeling results. The F-E grid has 1564 nodes and 1964 triangular elements. So far 26 models have been computed with various background strain rates and weighting of GPS data. Initial results show a good correspondence between predicted strain rate and Harvard CMT earthquake catalogue with m>5.5. The preferred fault slip rates in central and southeast Asia are generally less than the geologic estimates but within +/-2σ error bounds. The strain rate field and optimal fault slip rate estimates suggest that crustal deformation in the Persia-Tibet-Burma orogen is a mixture of distributed and quasi-rigid block deformation. A few such blocks are central Iran and southern Caspian basin, Tarim basin and Gobi platform, Qaidam basin, Ordos block and north of Tienshan in central Asia.

  20. Tectonothermal evolution of the Triassic flysch in the Bayan Har Orogen, Tibetan plateau

    Science.gov (United States)

    Wang, Hejing; Rahn, Meinert; Zhou, Jian

    2018-01-01

    The Bayan Har Orogen comprises a major part of the "Qingzang-Dianxi fold region" in western China. It preserves important information of the tectono-thermal evolution covering the time span from the closure of the Paleo-Tethys Ocean up to the formation of the Himalayas. Low temperature metamorphic indicators, such as mineral assemblages, illite "crystallinity" (IC), chlorite "crystallinity" (CC), illite polytype, b-cell dimension of K-white micas, geothermometry of selected minerals were analyzed. The values of Kübler index (KI) of the Triassic flysch in the Bayan Har Orogen range from 0.23-1.63°Δ2θ while Árkai index (ÁI) in a range of 0.21-0.60°Δ2θ. Iso-thermal zones mapped with KI describe a pair of anchizones and an anchiregion within the Bayan Har Orogen: the "Giant Yushu Anchizone" in the southwest (extending > 750 km long and 100 km wide), the "Zaling-Eling-Lakes Anchizone" in the center (about 150 km long and 40 km wide) and the "Xing-Tong-Zhe Anchiregion" in the northeast (covering an area of roughly 60,000 km2). They are separated by diagenetic zones. Peak metamorphic conditions are estimated around 280-330 °C and a low to intermediate (N. New Hampshire) pressure type. A slight change with increasing then decreasing pressure was observed from SW to NE. The relationship between anchimetamorphic pattern of Triassic flysch and large-scale folds and faults indicates syn- to post structural metamorphism. Compression at the end of the Triassic, induced by the interaction of the Tarim, North China and Indian blocks caused the closure of the Paleo-Tethys Ocean and led to the folding of the Triassic flysch within the Paleo-Tethys Ocean basin. Anchimetamorphism may have been caused by crustal thickening of > 10 km due to an accretionary wedge setting and a temperature increase in those rocks due to burial. Such a regional metamorphic pattern would provide important information for reconstruction of palaeotectonic-palaeogeograph and the evolutionary history

  1. Kinematics of post-orogenic extension and exhumation of the Taku Schist, NE Peninsular Malaysia

    Science.gov (United States)

    Md Ali, M. A.; Willingshofer, E.; Matenco, L.; Francois, T.; Daanen, T. P.; Ng, T. F.; Taib, N. I.; Shuib, M. K.

    2016-09-01

    Recent studies imply that the formation and evolution of many SE Asian basins was driven by extensional detachments or systems of low-angle normal faults that created significant crustal exhumation in their footwalls. In this context, the architecture of the Triassic Indosinian orogen presently exposed in Peninsular Malaysia is compatible with significant extension post-dating the orogenic event. In this study we performed a kinematic analysis based on fieldwork and microstructural observations in the Taku Schist, Kemahang granite and the surrounding Gua Musang sediments of northern Peninsular Malaysia in order to shed light on processes related to the build-up and subsequent demise of the Indosinian orogen. The first three phases of deformation were related to an overall period of E-W oriented contraction and burial metamorphism. These phases of deformation are characterized by isoclinal folding with flat lying axial plane cleavages (D1), asymmetrical folding, top-to-the-W-SW shearing (D2) and upright folding (D3). All are in general agreement with observations of the previously inferred Permo-Triassic Indosinian orogeny. During these times, the Taku Schist, a sequence of Paleozoic clastic sediments with mafic intercalations was metamorphosed to amphibolite facies. These rocks are most likely equivalent to the ones exposed in the Bentong-Raub suture zone. Structural relations suggest that the Triassic Kemahang pluton is syn-kinematic, which provides important constraints for the timing of these contractional events. We demonstrate that the overall shortening was followed by a hitherto undescribed extension in NW-SE direction resulting in the formation of a large-scale detachment, the Taku detachment, in northern Peninsular Malaysia. Extension probably reactivated the former subduction plane as a detachment and exhumed previously buried and metamorphosed rocks of similar lithological composition to the neighboring Bentong-Raub suture zone. Such a mechanism is

  2. Orogenic inheritance in Death Valley region, western US Basin and Range: implications for Neogene crustal extension.

    Science.gov (United States)

    Lima, R. D.; Hayman, N. W.; Prior, M. G.; Stockli, D. F.; Kelly, E. D.

    2016-12-01

    Deformation and temperature evolution during orogenic stages may influence later fabric development, thus controlling large-scale extensional processes that can occur millions of years later. Here, we describe pressure-temperature and fabric evolution from the Death Valley (DV) region and show how inherited fabrics, formed in late orogenic stages during Late Cretaceous time, influenced later Neogene age Basin and Range (BR) extension. The DV region is one of the most extended and thinned regions in the western US BR province, and the two of the ranges that bound the eastern valley expose basement rocks exhumed during the Neogene extension. In the Funeral range, it has been established that older (Precambrian) basement underwent Mesozoic age syn-deformational metamorphism during the Sevier-Laramide orogeny. In contrast, the Black Mountains record widespread tectonic stretching and magmatism of Miocene age on Precambrian basement, and have, overall, been lacking previous evidence of Mesozoic metamorphism and fabric development. In the Funeral Range Late Cretaceous migmatitic fabrics were overprinted by zones of high-strain fabrics formed due to melt-consuming reaction that define an overall P-T cooling path likely during late- to post-orogenesis. These fabrics form interconnected layers of quartz + biotite aggregates, in which individual quartz grains lack evidence of intracrystalline plastic deformation and show consistently random [c]-axis microfabrics. This suggests coupled reaction-diffusion processes that favored diffusion-assisted creep. New geochronometric results of melt products in the Black Mountains show evidence of partial melting of Late Cretaceous age. Contrasting with the neighboring Funeral Range, overprinting by extensional fabrics of Miocene age is widespread, and consists of high-strain, anastomosing foliation composed of retrograde products from preexisting, higher-temperature fabrics. These include interconnected fine-grained chlorite + quartz

  3. South Tien Shan orogenic belt: structure, magmatism and gold mineralization (Uzbekistan)

    Science.gov (United States)

    Koneev, Rustam; Seltmann, Reimer

    2014-05-01

    The Southern Tien Shan represents one of the key units of the Central Asian orogenic belt in Uzbekistan. Together with the Beltau-Kurama volcano-plutonic arc it formed as a result of subduction of the crust under the Turkistan paleoocean and the Kazakhstan continent, followed by collision and post-collisional strike-slip processes. The Southern Tien Shan is of particular interest due to its gold mineralisation. It hosts the giant Muruntau gold deposit and the large gold deposits of Amantaitau, Daugyztau, Myutenbay (Kyzylkum ore district) and Charmitan, Guzhumsay, Urtalik (Nurata ore district). The Middle Tienshan hosts within the Beltau-Kurama volcano-plutonic arc the Kurama ore district with the giant Kalmakyr Cu-Au porphyry and large epithermal Au-Ag deposits of Kochbulak and Kyzylalma. Yakubchuk et al. (2005) and others stress that the largest ore clusters are confined by the intersections of volcano-plutonic belts and transform faults in result of sinistral strike slip dislocations during the Permo-Carboniferous. Others believe that the ore giants are in addition controlled by hot spots - a mantle plume, superimposed on the crust architecture shaped by the subduction processes. Zircon U-Pb geochronology of main intrusive massifs of Uzbekistan (CERCAMS data) showed that granitoid magmatism is predominantly of postcollisional age, manifested in the accretionary units at 270-290 Ma, whereas subduction magmatism prevails as characteristic in the volcano-plutonic arc at 300-320 Ma. Determination of sulphide mineralization ages using Os-Re method (CERCAMS data), are respectively 283-289 Ma and 298-314 Ma. The studies were performed in the framework of IGCP- 592. References 1. Yakubchuk A.S., Shatov V.V., Kirwin D. et al., (2005) Gold and base metal metallogeny of the Central Asian Orogenic supercollage: Society of Economic Geologists, Inc. Economic Geology, 100th, Anniversary Volume, 1035-1068. 2. Groves, D.I., Goldfarb, R.J., Gebre-Mariam, M., Hagemann, S.G. and

  4. Multi-core Fibers in Submarine Networks for High-Capacity Undersea Transmission Systems

    DEFF Research Database (Denmark)

    Nooruzzaman, Md; Morioka, Toshio

    2017-01-01

    Application of multi-core fibers in undersea networks for high-capacity submarine transmission systems is studied. It is demonstrated how different architectures of submerged branching unit affect network component counts in long-haul undersea transmission systems......Application of multi-core fibers in undersea networks for high-capacity submarine transmission systems is studied. It is demonstrated how different architectures of submerged branching unit affect network component counts in long-haul undersea transmission systems...

  5. They Have Not Yet Begun to Fight: Women in the United States Navy Submarine Fleet

    Science.gov (United States)

    2016-03-11

    Navy Nurse Corps in 1908. The Nurse Corps was highly educated for the time and maintained high professional standards.3 Regardless, the struggle to...nation’s navies who integrated women into their submarine fleets ahead of the U.S. Navy. Norway, Sweden , Australian, and Great Britain all...Nations such as Norway and Sweden have been incorporating females into their submarines since the mid-1980s. 39 Sweden has had female sailors

  6. The Close Aboard Bastion: a Soviet ballistic missile submarine deployment strategy

    OpenAIRE

    Kreitler, Walter M

    1988-01-01

    Approved for public release; distribution is unlimited This thesis describes and analyzes a possible deployment posture for the Soviet ballistic missile submarine force. It examines the proposition that the Soviet Navy will establish a point defense, labeled "Close Aboard Bastions" (CABs), for its ballistic missile submarine fleet within the Soviet claimed 12 nautical mile territorial sea. This is a logical derivation of the currently widely held view that the Soviets will estab...

  7. Submarine channel evolution linked to rising salt domes, Gulf of Mexico, USA

    Science.gov (United States)

    Carter, Rachel C.; Gani, M. Royhan; Roesler, Toby; Sarwar, Abu K. M.

    2016-08-01

    An examination of halokinetics and channel evolution together in a deepwater system provides an opportunity to investigate how submarine channel morphology is locally affected by rising salt domes. The study area is located in the northern Gulf of Mexico (GOM), directly off the Louisiana continental slope in a prominent salt dome region. The influence of salt growth on submarine channel evolution is relatively understudied, particularly in the GOM. Utilizing high-resolution 3D seismic and well data and seismic geomorphology techniques, a long-lived (~ 3 Myr) Plio-Pleistocene submarine channel system has been investigated to show a relationship between variable phases of salt motion and planform morphology of preserved submarine channels. Our data suggest that local salt motion acts as a driver for submarine channel evolution. During the late Pliocene, when salt moved upward at a relatively fast rate, channels show distinct entrenchment with narrow channel belts and overall less sinuosity. When salt motion slowed down at the beginning of the Pleistocene, channels aggraded rapidly with preserved levees, and moved toward an equilibrium state with the expansion of channel belt widths. As our results indicate, the rate of salt diapirism exerted a first-order control on channel location and morphology and distribution of reservoir-prone units. This study cautions against readily invoking allogenic factors (e.g., sea level and climate) in explaining changes in submarine channel behavior and associated fan sedimentation, particularly in regions with salt tectonics.

  8. Observations of nearshore groundwater discharge: Kahekili Beach Park submarine springs, Maui, Hawaii

    Science.gov (United States)

    Swarzenski, Peter W.; Dulai, H.; Kroeger, K.D.; Smith, C.G.; Dimova, N.; Storlazzi, C. D.; Prouty, N.G.; Gingerich, S.B.; Glenn, C. R.

    2016-01-01

    Study regionThe study region encompasses the nearshore, coastal waters off west Maui, Hawaii. Here abundant groundwater—that carries with it a strong land-based fingerprint—discharges into the coastal waters and over a coral reef.Study focusCoastal groundwater discharge is a ubiquitous hydrologic feature that has been shown to impact nearshore ecosystems and material budgets. A unique combined geochemical tracer and oceanographic time-series study addressed rates and oceanic forcings of submarine groundwater discharge at a submarine spring site off west Maui, Hawaii.New hydrological insights for the regionEstimates of submarine groundwater discharge were derived for a primary vent site and surrounding coastal waters off west Maui, Hawaii using an excess 222Rn (t1/2 = 3.8 d) mass balance model. Such estimates were complemented with a novel thoron (220Rn,t1/2 = 56 s) groundwater discharge tracer application, as well as oceanographic time series and thermal infrared imagery analyses. In combination, this suite of techniques provides new insight into the connectivity of the coastal aquifer with the near-shore ocean and examines the physical drivers of submarine groundwater discharge. Lastly, submarine groundwater discharge derived constituent concentrations were tabulated and compared to surrounding seawater concentrations. Such work has implications for the management of coastal aquifers and downstream nearshore ecosystems that respond to sustained constituent loadings via this submarine route.

  9. Diatoms of the Mystery Lake, Taiwan (III

    Directory of Open Access Journals (Sweden)

    Jiunn-Tzong Wu

    2009-09-01

    Full Text Available This is the last part of study about the diatom flora found in the Mystery Lake, a slightly acidic lake situated within a hardwood nature preserve in northeastern Taiwan. In this article, we reported 17 species, belonging to 4 genera, 4 families, and 2 orders, based on scanning electron microscopic observations. The species described here, 9 are newly recorded in Taiwan. They are: Navicula cryptotenella, Navicula ingrata, Navicula subfasciata, Pinnularia borealis var. rectangularis, Pinnularia interrupta, Pinnularia maior, Sellaphora laevissima, S. vitabunda, and Nitzschia perminuta. In total, we found 76 diatom species in the surface sediments of this lake. Among them, 33 (43% are newly recorded to Taiwan. The present study indicates that this lake is characterized by high species diversity and high species richness, which are related to the oligotrophic and non-polluted environmental conditions.

  10. Public Health Emergency Response in Taiwan

    Science.gov (United States)

    Wu, Cheng-Hao; Lee, Tsui-Feng

    2017-01-01

    In recent years, growth of international travel and trade, as well as climate change, has resulted in the frequent emergence and reemergence of infectious diseases such as Ebola, Zika, and MERS. In 2016, Taiwan used the Joint External Evaluation (JEE) tool to evaluate its public health emergency response capacities and understand important areas for improvement. This article presents Taiwan's disaster and public health emergency response organizational structure, real-time integrated information, response processes, and command center structure. After reviewing the results of the JEE tool and drawing lessons from emergency response efforts in the United States, we provide 3 recommendations that may enhance Taiwan's public health emergency response capacities: establish common principles for disaster response regardless of which agency is in charge, standardize operation procedures, and perform regular training that includes nongovernmental organizations and a range of government departments. PMID:28418737

  11. Hillslope response to knickpoint migration in the Southern Appalachians: Implications for the evolution of post-orogenic landscapes

    Science.gov (United States)

    Wegmann, S.F.G.; Franke, K.L.; Hughes, S.; Lewis, R.Q.; Lyons, N.; Paris, P.; Ross, K.; Bauer, J.B.; Witt, A.C.

    2011-01-01

    The southern Appalachians represent a landscape characterized by locally high topographic relief, steep slopes, and frequent mass movement in the absence of significant tectonic forcing for at least the last 200 Ma. The fundamental processes responsible for landscape evolution in a post-orogenic landscape remain enigmatic. The non-glaciated Cullasaja River basin of south-western North Carolina, with uniform lithology, frequent debris flows, and the availability of high-resolution airborne lidar DEMs, is an ideal natural setting to study landscape evolution in a post-orogenic landscape through the lens of hillslope-channel coupling. This investigation is limited to channels with upslope contributing areas >2.7 km2, a conservative estimate of the transition from fluvial to debris-flow dominated channel processes. Values of normalized hypsometry, hypsometric integral, and mean slope vs elevation are used for 14 tributary basins and the Cullasaja basin as a whole to characterize landscape evolution following upstream knickpoint migration. Results highlight the existence of a transient spatial relationship between knickpoints present along the fluvial network of the Cullasaja basin and adjacent hillslopes. Metrics of topography (relief, slope gradient) and hillslope activity (landslide frequency) exhibit significant downstream increases below the current position of major knickpoints. The transient effect of knickpoint-driven channel incision on basin hillslopes is captured by measuring the relief, mean slope steepness, and mass movement frequency of tributary basins and comparing these results with the distance from major knickpoints along the Cullasaja River. A conceptual model of area-elevation and slope distributions is presented that may be representative of post-orogenic landscape evolution in analogous geologic settings. Importantly, the model explains how knickpoint migration and channel- hillslope coupling is an important factor in tectonically-inactive (i

  12. Carboniferous rifted arcs leading to an archipelago of multiple arcs in the Beishan-Tianshan orogenic collages (NW China)

    Science.gov (United States)

    Tian, Zhonghua; Xiao, Wenjiao; Windley, Brian F.; Zhang, Ji'en; Zhang, Zhiyong; Song, Dongfang

    2017-10-01

    The Beishan and East Tianshan Orogenic Collages in the southernmost Central Asian Orogenic Belt (CAOB) record the final stages of evolution of the Paleo-Asian Ocean. These collages and their constituent arcs have an important significance for resolving current controversies regarding their tectonic setting and age, consequent accretionary history of the southern CAOB, and the closure time of the Paleo-Asian Ocean. In this paper, we present our work on the southern Mazongshan arc and the northern Hongyanjing Basin in the Beishan Orogenic Collage (BOC), and our comparison with the Bogda arc and associated basins in the East Tianshan Orogenic Collage. Field relationships indicate that the Pochengshan fault defines the boundary between the arc and basin in the BOC. Volcanic rocks including basalts and rhyolites in the Mazongshan arc have bimodal calc-alkaline characteristics, an enrichment in large ion lithophile elements such as Rb, Ba, and Pb and depletion in high field-strength elements (e.g., Nb and Ta), which were probably developed in a subduction-related tectonic setting. We suggest that these bimodal calc-alkaline volcanic rocks formed in rifted arcs instead of post-orogenic rifts with mantle plume inputs. By making detailed geochemical comparisons between the Mazongshan arc and the Bogda arc to the west, we further propose that they are similar and both formed in arc rifts, and helped generate a Carboniferous archipelago of multiple arcs in the southern Paleo-Asian Ocean. These data and ideas enable us to postulate a new model for the tectonic evolution of the southern CAOB.

  13. EARLY STAGE OF THE CENTRAL ASIAN OROGENIC BELT BUILDING: EVIDENCES FROM THE SOUTHERN SIBERIAN CRATON

    Directory of Open Access Journals (Sweden)

    D. P. Gladkochub

    2017-01-01

    Full Text Available The origin of the Central-Asian Orogenic Belt (CAOB, especially of its northern segment nearby the southern margin of the Siberian craton (SC is directly related to development and closure of the Paleo-Asian Ocean (PAO. Signatures of early stages of the PAO evolution are recorded in the Late Precambrian sedimentary successions of the Sayan-Baikal-Patom Belt (SBPB on the southern edge of SC. These successions are spread over 2000 km and can be traced along this edge from north-west (Sayan area to south-east (Baikal area and further to north-east (Patom area. Here we present the synthesis of all available and reliable LA-ICP-MS U-Pb geochronological studies of detrital zircons from these sedimentary successions.

  14. Drainage Pattern, Along-Strike Topography and Three-Dimensional Construction of the Himalayan orogen

    Science.gov (United States)

    Yin, A.

    2005-12-01

    Past studies on the Himalayan orogen have mostly emphasized its 2-D evolution in cross-section view. As a result, how the orogen has grown in 3-D remains poorly understood. For example, it is not clear if the >1500-km long Main Central Thrust (MCT) and Main Boundary Thrust (MBT) were initiated synchronously along the whole orogen or started at one segment and then propagated laterally during subsequent fault motion. To clarify this issue, I examined the Himalayan drainage pattern, along-strike topography, and geometry and kinematics of growing contractional structures across both the Himalayan front and the Shillong Plateau. The main observations may be summarized as follows. (1) The five rivers that cut across the Himalaya are arranged approximately symmetric with respect to the Himalayan-arc axis (~85° E): the Arun River (87° E) is in the middle with the Sutlej (77° E) and Indus (72° E) Rivers in the west and the Subansiri (93° E) and Yalu-Brahmaputra (96° E) Rivers in the east. (2) Between the eastern and western syntaxes, south-flowing drainages east of 85.5° E are consistently deflected to the east by east-growing anticlines and thrusts, whereas drainages west of 85.5°E are deflected systematically to the west by west-growing anticlines and thrusts along the Himalayan front. The only region where no drainage deflection is observed is the Bhutan Himalaya. There all rivers flow straight across the Himalayan front. (3) The deflected drainage pattern indicates that the Shillong Plateau south of the eastern Himalaya has been growing westward. (4) The along-crest Himalayan topographic profile concaves downward, starting from ~5200 m just inside the two syntaxes and reaching 8848 m at Mt. Everest (~87° E). (5) There are a total of 17 major growing contractional structures in the Main Frontal Thrust Zone (MFTZ), with 10 in the west and 7 in the east. Each structure has a length between ~20 km and >150 km, but the west-growing structures in the west are

  15. Crustal structure of the Dabie orogenic belt (eastern China) inferred from gravity and magnetic data

    Science.gov (United States)

    Yang, Yu-shan; Li, Yuan-yuan

    2018-01-01

    In order to better characterize the crustal structure of the Dabie orogen and its tectonic history, we present a crustal structure along a 500 km long profile across the Dabie orogenic belt using various data processing and interpretation of the gravity and magnetic data. Source depth estimations from the spectral analysis by continuous wavelet transform (CWT) provide better constraints for constructing the initial density model. The calculated gravity effects from the initial model show great discrepancy with the observed data, especially at the center of the profile. More practical factors are then incorporated into the gravity modeling. First, we add a high density body right beneath the high pressure metamorphic (HPM) and ultrahigh pressure metamorphic (UHPM) belt considering the exposed HPM and UHPM rocks in the mid of our profile. Then, the anomalous bodies A, B, and C inferred from the CWT-based spectral analysis results are fixed in the model geometry. In the final crustal density structure, two anomalous bodies B and C with high density and low magnetization could possibly be attributed to metasomatised mantle materials by SiO2-rich melt derived from the foundering subducted mafic lower crust. Under the extensional environment in the early Cretaceous, the upwelling metasomatised mantle was partially melted to produce the parental magma of the post-collisional mafic-ultramafic intrusive rocks. As for the low density body A with strong magnetization located in the lower crust right beneath the HP and UHP metamorphic belt, it is more likely to be composed of serpentinized mantle peridotite (SMP). This serpentinized mantle peridotite body (SMPB) represents the emplacement of mantle-derived peridotites in the crust, accompanying the exhumation of the UHP metamorphic rocks.

  16. [The Taiwan Nurses Association and professional diplomacy].

    Science.gov (United States)

    Lee, Sheuan

    2014-08-01

    The Taiwan Nurses Association (TWNA) is publishing a special centenary issue to commemorate the 100th anniversary of the association in 2014. For this issue, TWNA invited the author to write a review article that addresses the involvement of the TWNA in professional diplomacy and international exchange over the past century. The author reviews the history of both TWNA and the International Council of Nurses and introduces the contributions of the association in the field of professional diplomacy and the positive contributions of many Taiwan nursing leaders to global healthcare and society. The purpose of the paper is to convey the traditions and experiences of TWNA forward to the next generation.

  17. Russia-Taiwan Relations: History and Perspectives

    Directory of Open Access Journals (Sweden)

    Sergey Vradiy

    2017-04-01

    Full Text Available From the point of view of potential possibilities for the development of business, scientific and technical cooperation, Taiwan could be considered as a prospective partner for Russian businessmen in East Asia. It is defined by the island’s high degree of import dependence upon main categories of raw material resources and by its leading role in producing a number of articles in the manufacturing industry. The article will briefly review the contemporary history of Russia’s relations with Taiwan. It will also analyze the current status and presume the possibility for future prospects of bilateral economic and trade relations.

  18. Taiwan: From China province to Japanese Colony

    Directory of Open Access Journals (Sweden)

    Marisela Conelly Ortiz

    2010-07-01

    Full Text Available This paper investigates the Japanese occupation of Taiwan from 1895 to 1945. It also explores the development of the Sino- Japanese War of 1894-1895 and the process of colonization. It explains the strengths and weaknesses of the Japanese military and civilian governments. It demonstrates that although the Japanese occupation brought economic welfare, it also brought discrimination towards Taiwanese people. The paper looks at the movement organized by Taiwanese intellectuals and students who wanted to gain political participation. Final remarks are given about the fifty years that Taiwan was occupied by the Japanese.

  19. Experimental modeling of gravity underflow in submarine channels

    Science.gov (United States)

    Islam, Mohammad Ashraful

    Active and relic meandering channels are common on the seafloor adjacent to continental margins. These channels and their associated submarine fan deposits are products of the density-driven gravity flows known as turbidity currents. Unlike natural rivers, few attempts have been made to explore the process of channel meandering in the submarine environment. This research focuses on resolving the flow field of submarine channels by conducting experiments in a large laboratory basin. Saline and particulate density flows were studied in a straight channel, a single bend sinuous channel with vertical sidewalls and a multiple-bend sinuous channel with sloping sidewalls. Instantaneous velocities in steady developed currents were measured using 3-component acoustic Doppler velocity probes. Excess fractional density was measured at selected locations by collecting water sample using a siphon rake. Turbulent kinetic energy and Reynolds stress components are derived from the instantaneous velocity data of the straight channel experiments. Structure functions for mean velocity, Reynolds stress and turbulent kinetic energy profiles are derived by fitting normalized data. The normalized Reynolds-averaged velocity shows excellent similarity collapse while the Reynolds-stress and the turbulent kinetic energy profiles display reasonable similarity. Vertical profiles of the turbulent kinetic energy display two peaks separated by a zone of low turbulence; the ratio of the maximum to the depth-averaged turbulent kinetic energy is approximately 1.5. Theoretical profile of turbulent kinetic energy is derived. Comparisons of experimentally and theoretically derived turbulent kinetic energy profiles show reasonable agreement except at the position of velocity maximum where the theoretical profile displays a very small value. Velocity profiles derived from the measurements with confined flow in the single bend channel reveal that channel curvature drives two helical flow cells, one

  20. Long-term flow monitoring of submarine gas emanations

    Science.gov (United States)

    Spickenbom, K.; Faber, E.; Poggenburg, J.; Seeger, C.

    2009-04-01

    One of the Carbon Capture and Storage (CCS) strategies currently under study is the sequestration of CO2 in sub-seabed geological formations. Even after a thorough review of the geological setting, there is the possibility of leaks from the reservoirs. As part of the EU-financed project CO2ReMoVe (Research, Monitoring, Verification), which aims to develop innovative research and technologies for monitoring and verification of carbon dioxide geological storage, we are working on the development of submarine long-term gas flow monitoring systems. Technically, however, these systems are not limited to CO2 but can be used for monitoring of any free gas emission (bubbles) on the seafloor. The basic design of the gas flow sensor system was derived from former prototypes developed for monitoring CO2 and CH4 on mud volcanoes in Azerbaijan. This design was composed of a raft floating on the surface above the gas vent to collect the bubbles. Sensors for CO2 flux and concentration and electronics for data storage and transmission were mounted on the raft, together with battery-buffered solar panels for power supply. The system was modified for installation in open sea by using a buoy instead of a raft and a funnel on the seafloor to collect the gas, which is then guided above water level through a flexible tube. Besides some technical problems (condensed water in the tube, movement of the buoys due to waves leading to biased measurement of flow rates), this setup provides a cost-effective solution for shallow waters. However, a buoy interferes with ship traffic, and it is also difficult to adapt this design to greater water depths. These requirements can best be complied by a completely submersed system. To allow unattended long-term monitoring in a submarine environment, such a system has to be extremely durable. Therefore, we focussed on developing a mechanically and electrically as simple setup as possible, which has the additional advantage of low cost. The system

  1. Using Google Earth for Submarine Operations at Pavilion Lake

    Science.gov (United States)

    Deans, M. C.; Lees, D. S.; Fong, T.; Lim, D. S.

    2009-12-01

    During the July 2009 Pavilion Lake field test, we supported submarine "flight" operations using Google Earth. The Intelligent Robotics Group at NASA Ames has experience with ground data systems for NASA missions, earth analog field tests, disaster response, and the Gigapan camera system. Leveraging this expertise and existing software, we put together a set of tools to support sub tracking and mapping, called the "Surface Data System." This system supports flight planning, real time flight operations, and post-flight analysis. For planning, we make overlays of the regional bedrock geology, sonar bathymetry, and sonar backscatter maps that show geology, depth, and structure of the bottom. Placemarks show the mooring locations for start and end points. Flight plans are shown as polylines with icons for waypoints. Flight tracks and imagery from previous field seasons are embedded in the map for planning follow-on activities. These data provide context for flight planning. During flights, sub position is updated every 5 seconds from the nav computer on the chase boat. We periodically update tracking KML files and refresh them with network links. A sub icon shows current location of the sub. A compass rose shows bearings to indicate heading to the next waypoint. A "Science Stenographer" listens on the voice loop and transcribes significant observations in real time. Observations called up to the surface immediately appear on the map as icons with date, time, position, and what was said. After each flight, the science back room immediately has the flight track and georeferenced notes from the pilots. We add additional information in post-processing. The submarines record video continuously, with "event" timestamps marked by the pilot. We cross-correlate the event timestamps with position logs to geolocate events and put a preview image and compressed video clip into the map. Animated flight tracks are also generated, showing timestamped position and providing timelapse

  2. Did a submarine landslide contribute to the 2011 Tohoku tsunami?

    KAUST Repository

    Tappin, David R.

    2014-09-28

    Many studies have modeled the Tohoku tsunami of March 11, 2011 as being due entirely to slip on an earthquake fault, but the following discrepancies suggest that further research is warranted. (1) Published models of tsunami propagation and coastal impact underpredict the observed runup heights of up to 40 m measured along the coast of the Sanriku district in the northeast part of Honshu Island. (2) Published models cannot reproduce the timing and high-frequency content of tsunami waves recorded at three nearshore buoys off Sanriku, nor the timing and dispersion properties of the waveforms at offshore DART buoy #21418. (3) The rupture centroids obtained by tsunami inversions are biased about 60 km NNE of that obtained by the Global CMT Project. Based on an analysis of seismic and geodetic data, together with recorded tsunami waveforms, we propose that, while the primary source of the tsunami was the vertical displacement of the seafloor due to the earthquake, an additional tsunami source is also required. We infer the location of the proposed additional source based on an analysis of the travel times of higher-frequency tsunami waves observed at nearshore buoys. We further propose that the most likely additional tsunami source was a submarine mass failure (SMF—i.e., a submarine landslide). A comparison of pre- and post-tsunami bathymetric surveys reveals tens of meters of vertical seafloor movement at the proposed SMF location, and a slope stability analysis confirms that the horizontal acceleration from the earthquake was sufficient to trigger an SMF. Forward modeling of the tsunami generated by a combination of the earthquake and the SMF reproduces the recorded on-, near- and offshore tsunami observations well, particularly the high-frequency component of the tsunami waves off Sanriku, which were not well simulated by previous models. The conclusion that a significant part of the 2011 Tohoku tsunami was generated by an SMF source has important implications for

  3. Seismic imaging of the Formosa Ridge cold seep site offshore of southwestern Taiwan

    Science.gov (United States)

    Hsu, Ho-Han; Liu, Char-Shine; Morita, Sumito; Tu, Shu-Lin; Lin, Saulwood; Machiyama, Hideaki; Azuma, Wataru; Ku, Chia-Yen; Chen, Song-Chuen

    2017-12-01

    Multi-scale reflection seismic data, from deep-penetration to high-resolution, have been analyzed and integrated with near-surface geophysical and geochemical data to investigate the structures and gas hydrate system of the Formosa Ridge offshore of southwestern Taiwan. In 2007, dense and large chemosynthetic communities were discovered on top of the Formosa Ridge at water depth of 1125 m by the ROV Hyper-Dolphin. A continuous and strong BSR has been observed on seismic profiles from 300 to 500 ms two-way-travel-time below the seafloor of this ridge. Sedimentary strata of the Formosa Ridge are generally flat lying which suggests that this ridge was formed by submarine erosion processes of down-slope canyon development. In addition, some sediment waves and mass wasting features are present on the ridge. Beneath the cold seep site, a vertical blanking zone, or seismic chimney, is clearly observed on seismic profiles, and it is interpreted to be a fluid conduit. A thick low velocity zone beneath BSR suggests the presence of a gas reservoir there. This "gas reservoir" is shallower than the surrounding canyon floors along the ridge; therefore as warm methane-rich fluids inside the ridge migrate upward, sulfate carried by cold sea water can flow into the fluid system from both flanks of the ridge. This process may drive a fluid circulation system and the active cold seep site which emits both hydrogen sulfide and methane to feed the chemosynthetic communities.

  4. The Quality of Life in Taiwan

    Science.gov (United States)

    Yao, Grace; Cheng, Yen-Pi; Cheng, Chiao-Pi

    2009-01-01

    The AsiaBarometer survey of 1,006 respondents shows that in Taiwan, people have access to modern utilities and digital media, signs of materialistic achievement, and yet are more concerned with physical security and financial safety than with personal growth. Regardless of their demographic backgrounds and value priorities, the Taiwanese, like…

  5. Empirical research on constructing Taiwan's ecoenvironmental ...

    African Journals Online (AJOL)

    In this paper, the material flow indicators and ecological footprint approach structured are adopted to construct eco-environmental stress indicators. We use relevant data to proceed with the empirical analyses on environmental stress and ecological impacts in Taiwan between the years of 1998 and 2007. Analysis of ...

  6. The Sale of FX Aircraft to Taiwan,

    Science.gov (United States)

    1982-02-01

    Angus M., "Military Capabilities in China," Current History, September 1975, pp. 70-74, 102. Geddes, I. Philip , "F-16 Co-production: An American Point...Premier Hopes Reagan Sends New Arms," New York Times, January 25, 1981. Seib , Gerald F., "U.S. Won’t Sell Advanced Jets Taiwan Sought," Wall Street

  7. Gestalt Group Dreamwork Demonstrations in Taiwan

    Science.gov (United States)

    Coven, Arnold B.

    2004-01-01

    The application of Gestalt dreamwork was explored with counselor education students and professors at two Taiwan universities. The literature indicates Asians are reluctant to disclose personal matters or to display emotions. Contrary to expectations, the Taiwanese participants readily enacted roles, were personally open, and expressed intense…

  8. Language Policy and Group Identification in Taiwan

    Science.gov (United States)

    Liu, Ruey-Ying

    2012-01-01

    Taiwan is a multicultural and multilingual society. Generally speaking, Taiwanese residents fall into one of four ethnic groups. Each ethnic group has a different cultural context and a preferred language. Therefore, one's use of language may reveal his/her identification with an ethnic group, and language policy implementation may imply the power…

  9. Sustainability of Higher Education Institutions in Taiwan

    Science.gov (United States)

    Su, H. Jenny; Chang, Tzu-chau

    2010-01-01

    Purpose: The purpose of this paper is to provide the rationale and context for recent national policy and funded initiatives to support sustainability developments within higher education in Taiwan, including practical and educational aspects. Concrete examples and specific outcomes are reviewed, to produce a profile across the higher education…

  10. Internet Addiction among High Schoolers in Taiwan.

    Science.gov (United States)

    Lin, Sunny S. J.; Tsai, Chin-Chung

    The purpose of this study was to develop a reliable and valid measurement for the identification of Internet addictive high school students. There were 615 subjects selected by a stratified sampling from the population of Taiwanese 10th to 12th graders. The final version of the Internet Addiction Scale for Taiwan High Schoolers (IAST) contained 20…

  11. Factors Related to Parenting Practices in Taiwan.

    Science.gov (United States)

    Chen, Fu-Mei; Luster Tom

    2002-01-01

    This study examined factors related to authoritarian and authoritative parenting practices among 463 Chinese mothers with preschoolers in Taiwan. Questionnaire findings suggested that maternal depression, child temperament, and degree of parenting daily hassles might have cross-culturally universal influence on parenting practices. Chinese…

  12. Petrological and zircon evidence for the Early Cretaceous granulite-facies metamorphism in the Dabie orogen, China

    Science.gov (United States)

    Gao, Xiao-Ying; Zhang, Qiang-Qiang; Zheng, Yong-Fei; Chen, Yi-Xiang

    2017-07-01

    An integrated study of petrology, mineralogy, geochemistry, and geochronology was carried out for contemporaneous mafic granulite and diorite from the Dabie orogen. The results provide evidence for granulite-facies reworking of the ultrahigh-pressure (UHP) metamorphic rock in the collisional orogen. Most zircons from the granulite are new growth, and their U-Pb ages are clearly categorized into two groups at 122-127 Ma and 188 ± 2 Ma. Although these two groups of zircons show similarly steep HREE patterns and variably negative Eu anomalies, the younger group has much higher U, Th and REE contents and Th/U ratios, much lower εHf(t) values than the older group. This suggests their growth is associated with different types of dehydration reactions. The older zircon domains contain mineral inclusions of garnet + clinopyroxene ± quartz, indicating their growth through metamorphic reactions at high pressures. In contrast, the young zircon domains only contain a few quartz inclusions and the garnet-clinopyroxene-plagioclase-quartz barometry yields pressures of 4.9 to 12.5 kb. In addition, the clinopyroxene-garnet Fe-Mg exchange thermometry gives temperatures of 738-951 °C. Therefore, the young zircon domains would have grown through peritectic reaction at low to medium pressures. The younger granulite-facies metamorphic age is in agreement not only with the adjacent diorite at 125 ± 1 Ma in this study but also the voluminous emplacement of coeval mafic and felsic magmas in the Dabie orogen. Mineral separates from both mafic granulite and its adjacent diorite show uniformly lower δ18O values than normal mantle, similar to those for UHP eclogite-facies metaigneous rocks in the Dabie orogen. In combination with major-trace elements and zircon Lu-Hf isotope compositions, it is inferred that the protolith of mafic granulites shares with the source rock of diorites, both being a kind of mafic metasomatites at the slab-mantle interface in the continental subduction channel

  13. Unravelling the long-term cooling history of the northern Pyrenees from rifting-to-orogenic evolution

    Science.gov (United States)

    Vacherat, Arnaud; Mouthereau, Frédéric; Pik, Raphaël; Bellahsen, Nicolas; Gautheron, Cécile; Bernet, Matthias; Tibari, Bouchaib; Pinna, Rosella; Daudet, Maxime; Radal, Julien

    2015-04-01

    Providing constraints on the temporal and spatial evolution of shortening in collision zones is key to reconstruct past plate motion. There are increasing evidences that the pre-orogenic architecture of the continental margins controls the development of continental accretion and therefore may be responsible for changes in the timing and rate of thrusting in collisional orogens. How this affect the thermal/exhumational record in the orogens is however little documented. Here, we study the northern Pyrenees (Ariège, Central North-Pyrenean Zone) that is exposed on the retro-wedge side of the orogen. This region developed in the vicinity of a domain that recorded hyper-extension and mantle exhumation and therefore potentially recorded the transition from rifting to collision. Apatite fission-track data from the granitic massifs of the Arize and Trois-Seigneurs Massifs indicate that collision-related exhumation started in the Early Eocene and lasted until Miocene. However, there are only scarce constraints on the former thermal history as there is not enough data from higher temperature thermochronometers. To gain a better resolution of the cooling/exhumation history from rift to mature collisional stage, we provide interpretations from new in-situ apatite and zircon fission-track and (U-Th-Sm)/He from the Arize and Trois Seigneurs massif. During extension, the studied granite recorded spatially variable thermal histories depending on the original rift-related architecture of the massifs. We show that the southern side of the Arize and 3S massif recorded significant cooling at 130-115 Ma from temperatures of 300-350°C, in agreement with RSCM temperatures obtained from the surrounding folded Mesozoic units. The northern sides recorded heating with subsidence. The massifs were rapidly cooled and exhumed between 50 and 35 Ma. Onset of convergence is only recorded in the hot basins as contraction resulted in ductile deformation. In this study, we show that the rift

  14. Submarine pyroclastic deposits in Tertiary basins, NE Slovenia

    Directory of Open Access Journals (Sweden)

    Polona Kralj

    2013-12-01

    Full Text Available In Tertiary basins of NE Slovenia, Upper Oligocene volcanic activity occurred in a submarine environment that experienced contemporaneous clastic sedimentation. Pyroclastic deposits are essentially related to gas- and watersupported eruption-fed density currents. At Trobni Dol, the Lako Basin, an over 100 m thick deposit formed by a sigle sustained volcanic explosion that fed gas-supported pyroclastic flow. Diagnostic features are large matrixshard content, normal grading of pumice lapilli, collapsed pumice lapilli and the presence of charcoal. In the Smrekovec Volcanic Complex, several but only up to 5 m thick deposits related to eruption-fed gassupported pyroclastic flows occur. Deposits settled from water-supported eruption-fed density currents form fining- and thinning-upward sedimentary units which resemble the units of volcaniclastic turbidites. Pyroclastic deposits related to gas- and water-supported density currents occur in an up to 1000 m thick succession composed of coherent volcanics, autoclastic, pyroclastic, reworked volcaniclastic and mixed volcaniclastic-siliciclastic deposits that indicate a complex explosive and depositional history of the Smrekovec Volcanic Complex.

  15. Breathing modes of Kolumbo submarine volcano (Santorini, Greece).

    Science.gov (United States)

    Bakalis, Evangelos; Mertzimekis, Theo J; Nomikou, Paraskevi; Zerbetto, Francesco

    2017-04-13

    Submarine volcanoes, such as Kolumbo (Santorini, Greece) are natural laboratories for fostering multidisciplinary studies. Their investigation requires the most innovative marine technology together with advanced data analysis. Conductivity and temperature of seawater were recorded directly above Kolumbo's hydrothermal vent system. The respective time series have been analyzed in terms of non-equilibrium techniques. The energy dissipation of the volcanic activity is monitored by the temperature variations of seawater. The venting dynamics of chemical products is monitored by water conductivity. The analysis of the time series in terms of stochastic processes delivers scaling exponents with turning points between consecutive regimes for both conductivity and temperature. Changes of conductivity are shown to behave as a universal multifractal and their variance is subdiffusive as the scaling exponents indicate. Temperature is constant over volcanic rest periods and a universal multifractal behavior describes its changes in line with a subdiffusive character otherwise. The universal multifractal description illustrates the presence of non-conservative conductivity and temperature fields showing that the system never retains a real equilibrium state. The existence of a repeated pattern of the combined effect of both seawater and volcanic activity is predicted. The findings can shed light on the dynamics of chemical products emitted from the vents and point to the presence of underlying mechanisms that govern potentially hazardous, underwater volcanic environments.

  16. High-efficiency airfoil rudders applied to submarines

    Directory of Open Access Journals (Sweden)

    ZHOU Yimei

    2017-03-01

    Full Text Available Modern submarine design puts forward higher and higher requirements for control surfaces, and this creates a requirement for designers to constantly innovate new types of rudder so as to improve the efficiency of control surfaces. Adopting the high-efficiency airfoil rudder is one of the most effective measures for improving the efficiency of control surfaces. In this paper, we put forward an optimization method for a high-efficiency airfoil rudder on the basis of a comparative analysis of the various strengths and weaknesses of the airfoil, and the numerical calculation method is adopted to analyze the influence rule of the hydrodynamic characteristics and wake field by using the high-efficiency airfoil rudder and the conventional NACA rudder comparatively; at the same time, a model load test in a towing tank was carried out, and the test results and simulation calculation obtained good consistency:the error between them was less than 10%. The experimental results show that the steerage of a high-efficiency airfoil rudder is increased by more than 40% when compared with the conventional rudder, but the total resistance is close:the error is no more than 4%. Adopting a high-efficiency airfoil rudder brings much greater lifting efficiency than the total resistance of the boat. The results show that high-efficiency airfoil rudder has obvious advantages for improving the efficiency of control, giving it good application prospects.

  17. Submarine springs and coastal karst aquifers: A review

    Science.gov (United States)

    Fleury, Perrine; Bakalowicz, Michel; de Marsily, Ghislain

    2007-06-01

    SummaryThis article reports on current knowledge of coastal karst aquifers, in which conduit flow is dominant, and its aim is to characterise the functioning of these systems which are closely linked to the sea. First, earlier and recent studies of these aquifers are discussed. On the basis of their findings, it can be shown that two essential mechanisms are involved in the functioning of these systems, i.e., aquifer discharge through submarine springs and saline intrusion through conduits open to the sea. Then, the conditions that give rise to these aquifers are described and particular emphasis is placed on the influence of deep karstification when the sea level falls. The base-level variations are attributed to the glaciations or, in the specific case of the Mediterranean, to the salinity crisis in the Messinian period. It is this inherited structure, sometimes containing very deep conduits below sea level, that today conditions the aquifer flow. The flow in the conduits open to the sea depends on the hydraulic head gradient between the aquifer and the sea and is therefore a function of the water density and head losses in the aquifer. This survey of coastal karst aquifers has revealed some common characteristics that show the development and/or functional capacity of their karstic drainage networks. A classification of such systems into three categories is proposed with the aim of assisting in the decision-making concerning potential exploitation of water resources in coastal regions.

  18. Sea-level-induced seismicity and submarine landslide occurrence

    Science.gov (United States)

    Brothers, Daniel S.; Luttrell, Karen M.; Chaytor, Jason D.

    2013-01-01

    The temporal coincidence between rapid late Pleistocene sea-level rise and large-scale slope failures is widely documented. Nevertheless, the physical mechanisms that link these phenomena are poorly understood, particularly along nonglaciated margins. Here we investigate the causal relationships between rapid sea-level rise, flexural stress loading, and increased seismicity rates along passive margins. We find that Coulomb failure stress across fault systems of passive continental margins may have increased more than 1 MPa during rapid late Pleistocene–early Holocene sea-level rise, an amount sufficient to trigger fault reactivation and rupture. These results suggest that sea-level–modulated seismicity may have contributed to a number of poorly understood but widely observed phenomena, including (1) increased frequency of large-scale submarine landslides during rapid, late Pleistocene sea-level rise; (2) emplacement of coarse-grained mass transport deposits on deep-sea fans during the early stages of marine transgression; and (3) the unroofing and release of methane gas sequestered in continental slope sediments.

  19. NESTOR - Neutrino Extended Submarine Telescope with Oceanographic Research

    CERN Document Server

    2002-01-01

    {\\bf NESTOR} is a deep-sea neutrino telescope that is being deployed in the Mediterranean off the south-west coast of the Peleponnese in Greece. Neutrinos, when they interact in the earth below or in the seawater around the detector, produce muons that can be observed by the Cherenkov radiation, which they emit. At an operating depth of 4000 metres, the detector is effectively shielded from muons produced in atmospheric interactions. {\\bf The site:} A major feature of the Ionian Sea floor is the Hellenic Trench, the deepest in the Mediterranean, which in places exceeds 5000 meters. It runs close to the western coast of the Peleponnese and is protected on its western side by the submarine Eastern Mediterranean Ridge. It is far from big city pollution or the effluent of major river systems flowing into the Mediterranean and is protected from deep-water perturbations.\\\\ The NESTOR site is located on a broad plateau some 8 $\\times$ 9 kilometres in area on the eastern side of the Hellenic Trench at a mean depth of...

  20. Ecostructuring of marine nematode communities by submarine groundwater discharge.

    Science.gov (United States)

    Grzelak, Katarzyna; Tamborski, Joseph; Kotwicki, Lech; Bokuniewicz, Henry

    2018-02-02

    Inputs of submarine groundwater discharge (SGD) to the coastal ocean may alter local and regional-scale biology. Here, we report on nematode assemblages along the north shore of Long Island, NY. We test if nematode communities differed between sites impacted by mixed fresh-saline SGD and where SGD is exclusively saline. Diversity of nematodes was low at sites impacted by fresh SGD and communities were dominated by a few opportunistic genera. Moreover, a set of typical freshwater nematode genera restricted to impacted sites was observed. Their presence in the marine coastal zone is exceptional and underlines the structuring role that fresh SGD plays in the local ecosystem. Saline SGD structured nematode assemblages differently compared to sites impacted by fresh SGD. The number of nematode genera was markedly higher at saline SGD sites, with a different community structure. This study highlights the importance to which inputs of fresh SGD may have on local ecosystem diversity in marine coastal environments. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Breathing modes of Kolumbo submarine volcano (Santorini, Greece)

    Science.gov (United States)

    Bakalis, Evangelos; Mertzimekis, Theo J.; Nomikou, Paraskevi; Zerbetto, Francesco

    2017-04-01

    Submarine volcanoes, such as Kolumbo (Santorini, Greece) are natural laboratories for fostering multidisciplinary studies. Their investigation requires the most innovative marine technology together with advanced data analysis. Conductivity and temperature of seawater were recorded directly above Kolumbo’s hydrothermal vent system. The respective time series have been analyzed in terms of non-equilibrium techniques. The energy dissipation of the volcanic activity is monitored by the temperature variations of seawater. The venting dynamics of chemical products is monitored by water conductivity. The analysis of the time series in terms of stochastic processes delivers scaling exponents with turning points between consecutive regimes for both conductivity and temperature. Changes of conductivity are shown to behave as a universal multifractal and their variance is subdiffusive as the scaling exponents indicate. Temperature is constant over volcanic rest periods and a universal multifractal behavior describes its changes in line with a subdiffusive character otherwise. The universal multifractal description illustrates the presence of non-conservative conductivity and temperature fields showing that the system never retains a real equilibrium state. The existence of a repeated pattern of the combined effect of both seawater and volcanic activity is predicted. The findings can shed light on the dynamics of chemical products emitted from the vents and point to the presence of underlying mechanisms that govern potentially hazardous, underwater volcanic environments.

  2. Total mercury flux and offshore transport via submarine groundwater discharge and coal-fired power plant in the Jiulong River estuary, China.

    Science.gov (United States)

    Wang, Jigang; Liu, Qian; Chen, Jinmin; Chen, Hongzhe; Lin, Hui; Sun, Xiuwu

    2018-02-01

    A mass balance of total mercury (Hg T , dissolved+particulate) is constructed for China's Jiulong River estuary based on measured Hg T concentrations in the surface water, sediment, porewater, and groundwater for May, August, and November 2009, combined with data from the literature. The Hg T mass budget results show that the dominant source (39-55%) is desulfurized seawater discharged from the Songyu coal-fired power plant. Submarine groundwater discharge (SGD)-derived Hg T flux into the estuary is equivalent to 8-58% of the Hg T input from the Jiulong River, which is remarkable when compared with SGD-derived Hg T fluxes reported in coastal systems worldwide. Hence, SGD is a significant pathway for the transport of Hg T into the Jiulong River estuary. The primary Hg T sinks is export to the Taiwan Strait (53-88%), which has important environmental implications on the Hg cycling and marine ecosystems in marginal seas. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Influence of the architecture of magma-poor hyperextended rifted margins on orogens produced by the closure of narrow versus wide oceans

    OpenAIRE

    Chenin, Pauline; MANATSCHAL, Gianreto; Picazo, Suzanne; Müntener, Othmar; Karner, Garry,; Johnson, Christopher ,; Ulrich, Marc

    2017-01-01

    International audience; Orogens resulting from the closure of narrow oceans, such as the Alps or the Pyrenees, usually lack voluminous synsubduction and synorogenic magmatism. Such orogenies are essentially controlled by mechanical processes in which the initial architecture of the original rifted margins strongly controls the architecture of the orogen. In this paper we first provide a synthesis of the structure, dimensions, and lithology of hyperextended rift systems and oceans, based on re...

  4. A discussion on the tectonic implications of Ediacaran late- to post-orogenic A-type granite in the northeastern Arabian Shield, Saudi Arabia

    Science.gov (United States)

    Robinson, F. A.; Bonin, B.; Pease, V.; Anderson, J. L.

    2017-03-01

    The transition from late-orogenic to post-orogenic magmatism following major orogenic episodes such as the Neoproterozoic to Cambrian East African Orogen (EAO) is an important, yet not well-understood geological event marking the cessation of subduction-controlled magmatism between buoyant lithospheric fragments. Forming the northern part of the EAO in the Arabian-Nubian Shield are three granitic suites that successively intruded the same northeastern area and post-date the 640 Ma major orogenic episode: (1) 620-600 Ma alkali feldspar (hypersolvous) granite with alkaline/ferroan/A-type geochemistry, (2) 599 Ma granite cumulates (some garnet-bearing) with calc-alkaline/magnesian affinities, and (3) 584-566 Ma alkali feldspar (hypersolvous) granite (aegirine-bearing) with a distinctive peralkaline/ferroan/A-type signature. Combining whole-rock geochemistry from the southern and northern Arabian Shield, suites 1 and 2 are suggested to be products of late-orogenic slab tear/rollback inducing asthenospheric mantle injection and lower crustal melting/fractionation toward A-type/ferroan geochemistry. Suite 3, however, is suggested to be produced by post-orogenic lithospheric delamination, which replaced the older mantle with new asthenospheric (rare earth element-enriched) mantle that ultimately becomes the thermal boundary layer of the new lithosphere. Major shear zones, such as the 620-540 Ma Najd Fault System (NFS), are some of the last tectonic events recorded across the Arabian Shield. Data presented here suggest that the NFS is directly related to the late-orogenic (620-600 Ma) slab tear/rollback in the northeastern Shield as it met with opposing subduction polarity in the southern Shield. Furthermore, this study infers that east and west Gondwana amalgamation interacted with opposing convergence reflected by the NFS.

  5. Metamorphic evolution and geochronology of the Dunhuang orogenic belt in the Hongliuxia area, northwestern China

    Science.gov (United States)

    Wang, Hao Y. C.; Wang, Juan; Wang, Guo-Dong; Lu, Jun-Sheng; Chen, Hong-Xu; Peng, Tao; Zhang, Hui C. G.; Zhang, Qian W. L.; Xiao, Wen-Jiao; Hou, Quan-Lin; Yan, Quan-Ren; Zhang, Qing; Wu, Chun-Ming

    2017-03-01

    Garnet-bearing mafic granulites and amphibolites from the Hongliuxia area of the southern Dunhuang orogenic belt, northwestern China, commonly occur as lenses or boudinages enclosed within metapelite or marble, which represent the block-in-matrix feature typical of orogenic mélange. Three to four generations of metamorphic mineral assemblages are preserved in these rocks. In the high-pressure amphibolites, prograde mineral assemblages (M1) occur as inclusions (hornblende + plagioclase + quartz ± chlorite ± epidote ± ilmenite) preserved within garnet porphyroblasts, and formed at 550-590 °C and 7.7-9.2 kbar based on geothermobarometry. The metamorphic peak mineral assemblages (M2) are composed of garnet + hornblende + plagioclase + quartz + clinopyroxene, as well as titanite + zircon + rutile + apatite as accessory minerals in the matrix, and are estimated to have formed at 640-720 °C and 14.1-16.0 kbar. The first retrograde assemblages (M3) are characterized by "white-eye socket" symplectites (hornblende + plagioclase + quartz ± biotite ± epidote ± magnetite) rimming garnet porphyroblasts, which formed at the expense of the garnet rims and adjacent matrix minerals during the decompression stage under P-T conditions of 610-630 °C and 5.6-11.8 kbar. The second retrograde assemblages (M4) are intergrowths of actinolite and worm-like quartz produced by the breakdown of the matrix hornblendes, and formed under P-T conditions of ∼490 °C and ∼2.8 kbar. For the high-pressure mafic granulites, the prograde assemblages (M1) are represented by plagioclase + quartz preserved within the garnet porphyroblasts. The metamorphic peak assemblages (M2) are garnet + matrix minerals (clinopyroxene + plagioclase + quartz + hornblende + rutile + zircon) and were estimated to have formed at ∼680 °C and ∼15.4 kbar. The retrograde assemblages (M3) are characterized by fine-grained patches of hornblende + plagioclase + quartz rimming the garnet porphyroblasts, as well as

  6. Timing of tectonic evolution of the East Kunlun Orogen, Northern Tibet Plateau

    Science.gov (United States)

    Dong, Yunpeng

    2017-04-01

    The East Kunlun Orogen, located at the northern Tibet Plateau, represents the western segment of the Central China Orogenic Belt which was formed by amalgamation of the North China blocks and South China blocks. It is a key to understanding the formation of Eastern Asian continent as well as the evolution of the Pangea supercontinent. Based on detailed geological mapping, geochemical and geochronological investigations, the orogen is divided into three main tectonic belts, from north to south, including the Northern Qimantagh, Central Kunlun and Southern Kunlun Belts by the Qimantagh suture, Central Kunlun suture and South Kunlun fault. The Qimantagh suture is marked by the Early Paleozoic ophiolites outcropped in the Yangziquan, Wutumeiren, and Tatuo areas, which consist mainly of peridotites, gabbros, diabases and basalts. Besides, the ophiolite in the Wutumeiren is characterized by occurring anorthosite while the ophiolite in the Tatuo occurring chert. The basalts and diabases from both Yaziquan and Tatuo areas display depletion of Nb, Ta, P and Ti, and enrichment of LILE, suggesting a subduction related tectonic setting. LA-ICP-MS zircon U-Pb age of 421 Ma for the diabase represents the formation age of the Yaziquan ophiolite, while the U-Pb ages of 490 Ma and 505 Ma for gabbro and anorthosite, respectively, constrain the formation age of the Tatuo ophiolite. The basaltic rocks in the Wutumeiren area display flat distribution of HFSEs (such as Nb, Ta, K, La, Ce, Pr, Nd, Zr, Sm, Eu, Ti, Dy, Y, Yb and Lu) and slightly enrichment in LREEs, while the peridotites showing depletion in MREEs. The LA-ICP-MS zircon U-Pb age of 431 Ma for the gabbro represents the formation age of the Wutumeiren ophiolite. Together with regional geology, we suggest herewith a back-arc basin tectonic setting during ca. 505-421 Ma at least for the Qimantagh suture. The Central Kunlun suture is represented by the ophiolite in the Wutuo area, which is characterized by depletion of Nb, Ta, P

  7. Influence of stiffness constant of stern bearing on vibration and acoustic radiation of whole submarine

    Directory of Open Access Journals (Sweden)

    WANG Lucai

    2018-02-01

    Full Text Available [Objectives] This paper studies the influence of the stiffness constant of a stern bearing on the vibration and acoustic radiation of a whole submarine.[Methods] Based on the form of SUBOFF, a whole submarine model is established in which the structures of the propeller and shaft are first formed in solid elements. Through calculating and comparing the structural vibration and acoustic radiation driven by a vertically excited force, the influence of the elastic coefficient of the stern bearing on the vibroacoustic of the overall submarine structure is mainly considered. [Results] It is demonstrated that the reduction of the elastic coefficient of the stern bearing leads to the convergence of structural vibration and acoustic radiation to the second order overall bending modal frequency, and the frequency gradually becomes lower, which can benefit the vibroacoustic reduction of submarines at frequencies higher than the second order overall bending modal frequency. [Conclusions] These results provide a reference for the acoustic design of submarine structures.

  8. Methane concentration inside a submarine mud volcano examined through seismic velocity profiles

    Science.gov (United States)

    Kioka, Arata; Tsuji, Takeshi; Otsuka, Hironori; Ashi, Juichiro

    2017-04-01

    Mud volcanoes are considered to be among largest geological sources releasing hydrocarbon gases into the atmosphere. Numerous studies have revealed their origins and compositions from submarine mud volcanoes. A recent long-term observation at a submarine mud volcano sheds light on that larger volume of methane gas than expected is escaped from deep-water mud volcanoes, suggesting that the global methane flux from the seafloor is likely underestimated. Yet, estimates of the gas amount inside mud volcanoes have been still challenging, because of the difficulty of in-situ measurements. This study provides a new model to bridge methane amounts and seismic velocities in fluidized mud conduits of submarine mud volcanoes. This model is universally applicable and enables estimates of methane concentration in the mud conduits, using the seismic velocity profile derived from reflection/refraction seismic and/or downhole logging data. In this study, (1) we examine our modeled results through deep-drilling data obtained at mud volcanoes in the Olimpi mud field of the central Mediterranean Ridge accretionary margin, to evaluate the difference between in situ methane amounts and those calculated from our model, and (2) apply our model to the seismic velocity profile derived from seicmic data to estimate the methane amount inside the submarine mud volcano in the Nankai accretionary margin. Our scheme may provide an opportunity to re-estimate the total methane flux from submarine mud volcanoes.

  9. Orogen-scale anticline revealed in the Southern Alps of New Zealand by structural thermochronology

    Science.gov (United States)

    Zhou, Renjie; Brandon, Mark

    2017-04-01

    A dense set of cooling ages from the Southern Alps reveals an orogen-scale anticline of cooling-age isosurfaces (isochrones) and provides an interesting example of structural thermochronology, where isochrones are used as structural markers. The isochrone concept is an integral aspect of the age-elevation method, but the latter implicitly assumes that all isochrones are horizontal. Our experience in New Zeland and elsewhere is that isochrones are commonly tilted after formation. We use a more general approach that solves for orientation of the isochrone surfaces, and also the slope of the age-elevation trend, where "elevation" is measured normal to the isochrone surfaces. In New Zealand, collision and convergence between the Pacific and Australian plates have resulted in the formation and continuing growth of the Southern Alps, a prototypical orogenic wedge. In the western side, the Southern Alps is bounded by the Alpine fault, along with deeply exhumed rocks from depths up to 25 km. There are 150 apatite and 200 zircon fission-track (AFT, ZFT) ages that cover the vast region of the South Island of New Zealand from Lake Summer to Lake Wanaka. The AFT ages range from Earth and Planetary Science Letters, 2010, doi: 10.1016/j.epsl.2010.05.022). We use a least-squares method to solve for a best-fit sequence of dipping isochrone surfaces. The solution specifies the strike, dip and spacing of the parallel isochrones, the last of which indicates the velocity of the isochrones passing through the closure depth. We find that the calculation of the entire dataset failed to yield reasonable results, implying nonplanar structures at the regional scale. Using subsets of data, we observed three distinct zones of isochrones from E to W across the South Island. 1) The large area east of the Southern Alps in the central South Island contains ZFT isochrones that dip shallowly (tilted to the east as they were advected through the large east-dipping retroshear zone that underlies the

  10. Orogenic gold mineralisation hosted by Archaean basement rocks at Sortekap, Kangerlussuaq area, East Greenland

    Science.gov (United States)

    Holwell, D. A.; Jenkin, G. R. T.; Butterworth, K. G.; Abraham-James, T.; Boyce, A. J.

    2013-04-01

    A gold-bearing quartz vein system has been identified in Archaean basement rocks at Sortekap in the Kangerlussuaq region of east Greenland, 35 km north-northeast of the Skaergaard Intrusion. This constitutes the first recorded occurrence of Au mineralisation in the metamorphic basement rocks of east Greenland. The mineralisation can be classified as orogenic style, quartz vein-hosted Au mineralisation. Two vein types have been identified based on their alteration styles and the presence of Au mineralisation. Mineralised type 1 veins occur within sheared supracrustal units and are hosted by garnet-bearing amphibolites, with associated felsic and ultramafic intrusions. Gold is present as native Au and Au-rich electrum together with arsenopyrite and minor pyrite and chalcopyrite in thin alteration selvages in the immediate wall rocks. The alteration assemblage of actinolite-clinozoisite-muscovite-titanite-scheelite-arsenopyrite-pyrite is considered to be a greenschist facies assemblage. The timing of mineralisation is therefore interpreted as being later and separate event to the peak amphibolite facies metamorphism of the host rocks. Type 2 quartz veins are barren of mineralisation, lack significant alteration of the wall rocks and are considered to be later stage. Fluid inclusion microthermometry of the quartz reveals three separate fluids, including a high temperature ( T h = 300-350 °C), H2O-CO2-CH4 fluid present only in type 1 veins that in interpreted to be responsible for the main stage of Au deposition and sulphidic wall rock alteration. It is likely that the carbonic fluids were actually trapped at temperatures closer to 400 °C. Two other fluids were identified within both vein types, which comprise low temperature (100-200 °C) brines, with salinities of 13-25 wt% eq. NaCl and at least one generation of low salinity aqueous fluids. The sources and timings of the secondary fluids are currently equivocal but they may be related to the emplacement of

  11. Intraplate geodynamics and magmatism in the evolution of the Central Asian Orogenic Belt

    Science.gov (United States)

    Yarmolyuk, V. V.; Kuzmin, M. I.; Ernst, R. E.

    2014-10-01

    The Central Asian Orogenic Belt (CAOB) was produced as a consequence of the successive closure of the Paleoasian Ocean and the accretion of structures formed within it (island arcs, oceanic islands, and backarc basins) to the Siberian continent. The belt started developing in the latest Late Neoproterozoic, and this process terminated in the latest Permian in response to the collision of the Siberian and North China continents that resulted in closure of the Paleoasian ocean (Metcalfe, 2006; Li et al., 2014; Liu et al., 2009; Xiao et al., 2010; Didenko et al., 2010). Throughout the whole evolutionary history of this Orogenic Belt, a leading role in its evolution was played by convergent processes. Along with these processes, an important contribution to the evolution of the composition and structure of the crust in the belt was made by deep geodynamic processes related to the activity of mantle plumes. Indicator complexes of the activity of mantle plumes are identified, and their major distribution patterns in CAOB structures are determined. A number of epochs and areas of intraplate magmatism are distinguished, including the Neoproterozoic one (Rodinia breakup and the origin of alkaline rock belt in the marginal part of the Siberian craton); Neoproterozoic-Early Cambrian (origin of oceanic islands in the Paleoasian Ocean); Late Cambrian-Early Ordovician (origin of LIP within the region of Early Caledonian structures in CAOB); Middle Paleozoic (origin of LIP in the Altai-Sayan rift system); Late Paleozoic-Early Mesozoic (origin of the Tarim flood-basalt province, Central Asian rift system, and a number of related zonal magmatic areas); Late Mesozoic-Cenozoic (origin of continental volcanic areas in Central Asia). Geochemical and isotopic characteristics are determined for magmatic complexes that are indicator complexes for areas of intraplate magmatism of various age, and their major evolutionary trends are discussed. Available data indicate that mantle plumes

  12. Linking the Timescales of Orogenic growth and Climatic Feedback in Southern New Zealand: A Pilot Study

    Science.gov (United States)

    Batt, G. E.; Zwingmann, H.

    2008-12-01

    Orogenic systems are the rejuvenating engines of the Global Earth system, converting the thermal and kinetic energy of tectonic processes into uplift of the landscape that, in turn, drives erosion and renews the fertility of the biosphere. Understanding the relationships between tectonic uplift, erosion, and local climate, however, lags behind quantitative understanding of other areas of Earth Systems Science. The challenge in developing this field lies in the requirement of independently documenting the long-term evolution of these three systems for a given region. Although sensitive chronometric constraint has long been successfully derived for climatic and structural systems, an inability to constrain the temporal evolution of topography has represented a fundamental deficiency in our understanding. Without such chronometric constraint, correlation and testing of models of fundamental links between tectonic forcing and climate variation remain essentially arbitrary and artificial. We present here the results of a pilot investigation into the feasibility of dating authigenic illite extracted from Miocene-Recent paleosols and weathered surfaces formed during the development of the Southern Alps of New Zealand. Chamberlain et al. (1999) have previously attributed a stable isotope signature resolved in Kaolinite from these weathered horizons as recording development of strongly asymmetric climatic zonation as a consequence of Mio-Pliocene growth of the Southern Alps. By re-visiting this approach to assessing the topographic record of the orogen through isotopic proxy measurements, and combining this with direct chronological constraint of the weathered materials making up this record, we hope to examine the potential of developing a robust framework in which to investigate and model the linked processes of mountain growth and local scale climatic effects. Initial results have been mixed. Clay fractions have been separated from 7 variably weathered paleosols and

  13. The pre-Devonian tectonic framework of Xing'an-Mongolia orogenic belt (XMOB) in north China

    Science.gov (United States)

    Xu, Bei; Zhao, Pan; Wang, Yanyang; Liao, Wen; Luo, Zhiwen; Bao, Qingzhong; Zhou, Yongheng

    2015-01-01

    A new tectonic division of the Xing'an-Mongolia orogenic belt (XMOB) in north China has been presented according to our research and a lot of new data of tectonics, geochronology and geochemistry. Four blocks and four sutures have been recognized in the XMOB, including the Erguna (EB), Xing'an-Airgin Sum (XAB), Songliao-Hunshandake (SHB), and Jiamusi (JB), and Xinlin-Xiguitu (XXS), Xilinhot-Heihe (XHS), Mudanjiang (MS) and Ondor Sum-Yongji sutures (OYS). The framework of the XMOB is characterized by a tectonic collage of the blocks and orogenic belts between them. Different Precambrian basements have been found in the blocks, including the Neoproterozoic metamorphic rocks and plutons in the EB, the Neoproterozoic metamorphic rocks in western and eastern of segments of the XAB, Mesoproterozoic and Neoproterozoic metamorphic rocks in middle segments of the XAB, respectively, the Neoproterozoic metamorphic rocks and Mesoproterozoic volcanic rocks and plutons in the SHB, and Neoproterozoic metamorphic rocks in the JB. The XXS resulted from a northwestward subduction of the XAB beneath the EB during the Cambrian, which was followed by the forming of the XHS and OYS in the northwest and south margins of the SHB in the Silurian, respectively. The MS was caused by a westward subduction of the JB beneath the east margin of the SHB during the middle Devonian. The three Cambrian, Silurian and middle Devonian events indicate that the XMOB belongs to a pre-middle Devonian multiple orogenic belt in the Central Asian Orogenic Belt (CAOB). Forming of the XMOB suggests that the southeast part of the Paleo Asian Ocean closed before the middle Devonian.

  14. Neoproterozoic to Paleozoic Geological Evolution of Mongolia: Constraints on Modes of "Crustal Growth" in the Central Asian Orogenic Belt

    Science.gov (United States)

    Macdonald, F. A.; Bold, U.; Smith, E.; Olin, P. H.; Crowley, J. L.; Schmitz, M. D.

    2012-12-01

    The Central Asian Orogenic Belt (CAOB) is widely considered the largest area of Phanerozoic juvenile crustal growth on Earth. However, the timing and nature of the orogenic events in the core of the CAOB in Mongolia has remained poorly constrained due to a dearth of detailed geological and geochronological studies. To bridge this gap and test models of crustal growth, here we refine the sequencing of geological events by focusing on the formation and destruction of Neoproterozoic and Paleozoic tectonic basins. Mongolia's basins record a complete Neoproterozoic to Cambrian Wilson cycle with rifting of the Mongolian continent at ca. 700 Ma, the development of a Cryogenian to Ediacaran thermally subsiding passive margin, an arc-continent collision at ca. 520 Ma, and a continent-arc-continent collision at ca. 500 Ma. During this collisional orogeny, that is the Cambrian Altaids, crustal growth occurred largely through the obduction of ophiolites. Rifting of the southern margin occurred during the Ordovician Period, with the development of a Silurian passive margin. Oblique northwest-dipping subduction was initiated during the Devonian and resulted in a transpressional accretionary orogen. The CAOB culminated with a continent-arc-continent collision and the accretion of the North China and Tarim Blocks in the latest Permian. The Devonian to early Permian accretionary orogen is associated not only with voluminous plutonism, but also, major translational structures oblique to the margin resulting in the appearance of many accreted terranes. These data are consistent with existing coarse Hf and Nd isotopic data, but also provide a framework for future detailed studies. Although our geological constraints suggest distinct periods of apparent crustal growth through either collisional or accretionary orogenies, net crustal growth after accounting for recycling is equivocal.

  15. Mass elevation and lee effects markedly lift the elevational distribution of ground beetles in the Himalaya-Tibet orogen

    Science.gov (United States)

    Schmidt, Joachim; Böhner, Jürgen; Brandl, Roland; Opgenoorth, Lars

    2017-01-01

    Mass elevation and lee effects markedly influence snow lines and tree lines in high mountain systems. However, their impact on other phenomena or groups of organisms has not yet been quantified. Here we quantitatively studied their influence in the Himalaya–Tibet orogen on the distribution of ground beetles as model organisms, specifically whether the ground beetle distribution increases from the outer to the inner parts of the orogen, against latitudinal effects. We also tested whether July temperature and solar radiation are predictors of the beetle’s elevational distribution ranges. Finally, we discussed the general importance of these effects for the distributional and evolutionary history of the biota of High Asia. We modelled spatially explicit estimates of variables characterizing temperature and solar radiation and correlated the variables with the respective lower elevational range of 118 species of ground beetles from 76 high-alpine locations. Both July temperature and solar radiation significantly positively correlated with the elevational ranges of high-alpine beetles. Against the latitudinal trend, the median elevation of the respective species distributions increased by 800 m from the Himalayan south face north to the Transhimalaya. Our results indicate that an increase in seasonal temperature due to mass elevation and lee effects substantially impact the regional distribution patterns of alpine ground beetles of the Himalaya–Tibet orogen and are likely to affect also other soil biota there and in mountain ranges worldwide. Since these effects must have changed during orogenesis, their potential impact must be considered when biogeographic scenarios based on geological models are derived. As this has not been the practice, we believe that large biases likely exist in many paleoecological and evolutionary studies dealing with the biota from the Himalaya-Tibet orogen and mountain ranges worldwide. PMID:28339461

  16. A giant mass failure in the northern flank of the Kueishantao Island off northeastern Taiwan: debris avalanches and related structures in the offshore downslope

    Science.gov (United States)

    Huang, P. C.; Hsu, S. K.; Tsai, C. H.; Chen, S. C.

    2016-12-01

    Based on the ignimbrite layers, previous studies have shown that Kueishantao volcanic island has probably erupted four times in 7000 years. Strong smell of sulfur can easily detect at east of the island with some plumes from the seabed. In May 2016, an earthquake with magnitude 5 occurred to northeast of the island which has triggered small collapse events in the eastern subaerial part. Recent geophysical surveys have also revealed the distribution of submarine debris avalanches in the north, south and east part off Kueishantao volcanic island. With high-resolution swath bathymetric data, we can observe some debris avalanches distributed with hummocky relief around the island. In this study, we present the marine geophysical data in order to have better understanding of the landslide mechanism from the offshore data of the Kueishantao island, especially with the multi-beam bathymetric data, acoustic backscatter analysis, subbottom profile, sidescan sonar and 3.5kHz echo-sounder. At the north of the island, large-scale debris avalanches extend around 4 km northward with the several blocks height up to more than twenty meters; and, the offshore area of deposit is about 5 km2 of hummocky topography distribution. The scale of debris avalanches may be related to the horseshoe scar of subaerial flank and also submarine flank collapsed events. Nevertheless, to identify the landslide history, we need to analyze the related core data in the future. By analyzing the high-resolution geophysical data, we will discuss the possible mechanism or factors that trigger subaerial flank collapse events and also the transportation of the debris avalanches to the submarine basin. The large-scale collapse events may produce tsunamis and directly affect the coast of northeastern Taiwan.

  17. Crustal surface wave velocity structure of the east Albany-Fraser Orogen, Western Australia, from ambient noise recordings

    Science.gov (United States)

    Sippl, C.; Kennett, B. L. N.; Tkalčić, H.; Gessner, K.; Spaggiari, C. V.

    2017-09-01

    Group and phase velocity maps in the period range 2-20 s for the Proterozoic east Albany-Fraser Orogen, Western Australia, are extracted from ambient seismic noise recorded with the 70-station ALFREX array. This 2 yr temporary installation provided detailed coverage across the orogen and the edge of the Neoarchean Yilgarn Craton, a region where no passive seismic studies of this scale have occurred to date. The surface wave velocities are rather high overall (>3 km s-1 nearly everywhere), as expected for exposed Proterozoic basement rocks. No clear signature of the transition between Yilgarn Craton and Albany-Fraser Orogen is observed, but several strong anomalies corresponding to more local geological features were obtained. A prominent, NE-elongated high-velocity anomaly in the northern part of the array is coincident with a Bouguer gravity high caused by the upper crustal metamorphic rocks of the Fraser Zone. This feature disappears towards longer periods, which hints at an exclusively upper crustal origin for this anomaly. Further east, the limestones of the Cenozoic Eucla Basin are clearly imaged as a pronounced low-velocity zone at short periods, but the prevalence of low velocities to periods of ≥5 s implies that the uppermost basement in this area is likewise slow. At longer periods, slightly above-average surface wave velocities are imaged below the Eucla Basin.

  18. CFD RANS Simulations on a Generic Conventional Scale Model Submarine: Comparison between Fluent and OpenFOAM

    Science.gov (United States)

    2015-09-01

    1 – Hydrodynamics”, Defence Science and Technology Organisation Technical Report DSTO-TR-1622, 2004. UNCLASSIFIED DST-Group-TN-1449 UNCLASSIFIED...17 7. Joubert, P.N., “Some Aspects of Submarine Design Part 2– Shape of a Submarine 2026”, Defence Science and Technology Organisation Technical

  19. Climate change impacts in Zhuoshui watershed, Taiwan

    Science.gov (United States)

    Chao, Yi-Chiung; Liu, Pei-Ling; Cheng, Chao-Tzuen; Li, Hsin-Chi; Wu, Tingyeh; Chen, Wei-Bo; Shih, Hung-Ju

    2017-04-01

    There are 5.3 typhoons hit Taiwan per year on average in last decade. Typhoon Morakot in 2009, the most severe typhoon, causes huge damage in Taiwan, including 677 casualty and roughly NT 110 billion (3.3 billion USD) in economic loss. Some researches documented that typhoon frequency will decrease but increase in intensity in western North Pacific region. It is usually preferred to use high resolution dynamical model to get better projection of extreme events; because coarse resolution models cannot simulate intense extreme events. Under that consideration, dynamical downscaling climate data was chosen to describe typhoon satisfactorily. One of the aims for Taiwan Climate Change Projection and Information Platform (TCCIP) is to demonstrate the linkage between climate change data and watershed impact models. The purpose is to understand relative disasters induced by extreme rainfall (typhoons) under climate change in watersheds including landslides, debris flows, channel erosion and deposition, floods, and economic loss. The study applied dynamic downscaling approach to release climate change projected typhoon events under RCP 8.5, the worst-case scenario. The Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability (TRIGRS) and FLO-2D models, then, were used to simulate hillslope disaster impacts in the upstream of Zhuoshui River. CCHE1D model was used to elevate the sediment erosion or deposition in channel. FVCOM model was used to asses a flood impact in urban area in the downstream. Finally, whole potential loss associate with these typhoon events was evaluated by the Taiwan Typhoon Loss Assessment System (TLAS) under climate change scenario. Results showed that the total loss will increase roughly by NT 49.7 billion (1.6 billion USD) in future in Zhuoshui watershed in Taiwan. The results of this research could help to understand future impact; however model bias still exists. Because typhoon track is a critical factor to consider regional

  20. Numerical Simulation of Barotropic Tides around Taiwan

    Directory of Open Access Journals (Sweden)

    Chih-Kai Hu

    2010-01-01

    Full Text Available A 1/12°, 2-D barotropic tide model was used to examine the characteristics of barotropic tides and to improve the accuracy of predicting tidal sea levels and currents in the seas around Taiwan. The form ratio suggests that tides are predominantly semidiurnal in the northern reaches of the Taiwan Strait and mixed of diurnal and semidiurnal elsewhere around Taiwan. When the dominant M2 wave enters the Strait from the north, its amplitude is magnified to ~2 m in the middle, and then decreases rapidly toward the south end of the Strait. The predominance of diurnal tides along the southwest to the south coast of Taiwan is attributed to the quasi-resonance of diurnal waves in the South China Sea. The tidal range is small and tidal currents are weak off the east coast of Taiwan. Barotropic tidal energy is mostly dissipated on the shallow banks of the southwestern Strait. Results summarized from sensitivity tests on the bottom drag coefficient (CD and horizontal eddy viscosity (AM indicate that CD = 0.0015 - 0.00175 and AM = 150 m2 s-1 lead to the best model-data fit when compared to the observed tidal sea levels at ten reference tide-gauge stations around Taiwan. The averaged root-mean-squared (RMS differences of the simulated tidal sea level for the six principal constituents of O1, P1, K1, N2, M2, and S2 are significantly reduced to 1.3, 0.7, 2.0, 1.6, 5.1, and 3.1 cm, respectively, compared to that calculated from a 0.5° resolution global tide harmonic constant database, NAO.99b (Matsumoto et al. 2000. The averaged RMS differences of barotropic tidal currents (U, V for O1, K1, M2, and S2 are (0.92, 1.64, (1.17, 0.61, (3.88, 2.37, and (1.52, 1.20 cm s-1. A database of tidal sea levels and current harmonic constants, TWTIDE08, for Q1, O1, P1, K1, J1, OO1, 2N2, μ2, N2, ν2, M2, L2, T2, S2, and K2 is established with this study.

  1. High accuracy station moving method for total station in submarine construction

    Directory of Open Access Journals (Sweden)

    MIN Shaosong

    2017-10-01

    Full Text Available [Objectives] When we measure submarine pressure hulls using a total station, it is essential to set several stations in order to complete the measurement of the whole cabin due to the complicated measuring environment. However, there are many restrictions related to the total station itself when moving stations, and it is also difficult to ensure measuring accuracy and satisfy the requirements of submarine measurement in complicated environments.[Methods] As such, a new station moving method is presented which can automatically establish standing relationships by measuring common points at every measuring position.[Results] This method can significantly improve accuracy and efficiency.[Conclusions] The experiment shows that the results of the new station moving method can meet sub-pixel precision and satisfy submarine measurement requirements with high accuracy.

  2. Submarine landslide and tsunami hazards offshore southern Alaska: Seismic strengthening versus rapid sedimentation

    Science.gov (United States)

    Sawyer, Derek E.; Reece, Robert S.; Gulick, Sean P. S.; Lenz, Brandi L.

    2017-08-01

    The southern Alaskan offshore margin is prone to submarine landslides and tsunami hazards due to seismically active plate boundaries and extreme sedimentation rates from glacially enhanced mountain erosion. We examine the submarine landslide potential with new shear strength measurements acquired by Integrated Ocean Drilling Program Expedition 341 on the continental slope and Surveyor Fan. These data reveal lower than expected sediment strength. Contrary to other active margins where seismic strengthening enhances slope stability, the high-sedimentation margin offshore southern Alaska behaves like a passive margin from a shear strength perspective. We interpret that seismic strengthening occurs but is offset by high sedimentation rates and overpressure. This conclusion is supported by shear strength outside of the fan that follow an active margin trend. More broadly, seismically active margins with wet-based glaciers are susceptible to submarine landslide hazards because of the combination of high sedimentation rates and earthquake shaking.

  3. The Zambezi Channel: A new perspective on submarine channel evolution at low latitudes

    Science.gov (United States)

    Wiles, E.; Green, A.; Watkeys, M.; Jokat, W.

    2017-06-01

    Submarine channels are not stand-alone systems. They are long-lived systems modified by imperceptibly slow processes and rapid gravity flows, in some part controlled by hinterland dynamics. The submarine Zambezi Channel, within the Mozambique Channel, receives sediment from the Zambezi River catchment which has a dynamic tectonic and morphological history. Using recently collected multibeam bathymetry and PARASOUND data we discuss the geomorphology of the Zambezi Channel. Results show this system to be distinct in geomorphologic character when compared to other low-latitude submarine channels, sharing similarities with high-latitude systems. We propose a new, source-to-sink, hypothesis for the evolution of the Zambezi Channel, taking in to consideration hinterland tectonics, palaeo-lake development, river capture and rapid gravity flows. This hypothesis accounts for the unique present-day anatomy of the Zambezi Channel within the dynamic framework of the systems regional setting.

  4. Research on Big Data Attribute Selection Method in Submarine Optical Fiber Network Fault Diagnosis Database

    Directory of Open Access Journals (Sweden)

    Chen Ganlang

    2017-11-01

    Full Text Available At present, in the fault diagnosis database of submarine optical fiber network, the attribute selection of large data is completed by detecting the attributes of the data, the accuracy of large data attribute selection cannot be guaranteed. In this paper, a large data attribute selection method based on support vector machines (SVM for fault diagnosis database of submarine optical fiber network is proposed. Mining large data in the database of optical fiber network fault diagnosis, and calculate its attribute weight, attribute classification is completed according to attribute weight, so as to complete attribute selection of large data. Experimental results prove that ,the proposed method can improve the accuracy of large data attribute selection in fault diagnosis database of submarine optical fiber network, and has high use value.

  5. Chemical Fluxes from a Recently Erupted Submarine Volcano on the Mariana Arc

    Science.gov (United States)

    Buck, N. J.; Resing, J. A.; Lupton, J. E.; Larson, B. I.; Walker, S. L.; Baker, E. T.

    2016-12-01

    While hydrothermal circulation is paramount to the geochemical budget for a wide array of elements, relatively few flux estimates exist in the literature. To date most studies have concentrated on constraining global and vent-field scale inputs originating from ocean spreading ridges. The goal of this study is to directly measure the chemical flux from an active submarine volcano injecting hydrothermal fluids into the surface ocean. Ahyi Seamount, a submarine intraoceanic arc volcano located in the Northern Mariana Islands, has a summit depth TSM and total and dissolved Fe and Mn. Laboratory analyses found enriched concentrations of H2, 3He, CO2 and Fe, consistent with a recent eruption. Preliminary flux calculations estimate a Fe input of 16 mmol s-1. This indicates shallow submarine arc volcanoes are capable of supplying appreciable quantities of Fe into the surface ocean. Further laboratory analyses and calculations to characterize and constrain the fluxes of other chemical constituents are underway.

  6. Air blast injuries killed the crew of the submarine H.L. Hunley.

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    Rachel M Lance

    Full Text Available The submarine H.L. Hunley was the first submarine to sink an enemy ship during combat; however, the cause of its sinking has been a mystery for over 150 years. The Hunley set off a 61.2 kg (135 lb black powder torpedo at a distance less than 5 m (16 ft off its bow. Scaled experiments were performed that measured black powder and shock tube explosions underwater and propagation of blasts through a model ship hull. This propagation data was used in combination with archival experimental data to evaluate the risk to the crew from their own torpedo. The blast produced likely caused flexion of the ship hull to transmit the blast wave; the secondary wave transmitted inside the crew compartment was of sufficient magnitude that the calculated chances of survival were less than 16% for each crew member. The submarine drifted to its resting place after the crew died of air blast trauma within the hull.

  7. Origin of the Easter Submarine Alignment: morphology and structural lineaments

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    Cristián Rodrigo

    2014-10-01

    Full Text Available The Easter submarine alignment corresponds to a sequence of seamounts and oceanic islands which runs from the Ahu-Umu volcanic fields in the west to its intersection with the Nazca Ridge in the east, with a total length of about 2.900 km and a strike of N85°E. Recent bathymetric compilations that include combined satellite derived and shipboard data (Global Topography and multibeam bathymetric data (from NGDC-NOAA are interpreted both qualitatively and quantitatively by using a morphological analysis, which was comprised of the determination of bathymetric patterns, trends in lineations and structures; height measurements, computation of basal areas and volumes of seamounts, in order to establish clues on the origin of this seamount chain and to establish relationships with the regional tectonics. In the study region 514 seamounts were counted, of which 334 had a basal area less than the reference seamount (Moai. In general, the largest seamounts (>1000 m in height tend to align and to have a larger volume, with an elongation of their bases along the seamount chain. On the other hand, smaller seamounts tend to be distributed more randomly with more circular bases. As a consequence of the morphological analysis, the best possible mechanism that explains the origin of the seamount chain is the existence of a localized hotspot to the west of the Salas y Gómez Island. The corresponding plume would contribute additional magmatic material towards the East Pacific Rise through canalizations, whose secondary branches would feed intermediate volcanoes. It is possible that within the Easter Island region there would be another minor contribution through fractures in the crust, due to the crustal weakening that was produced by the Easter Fracture Zone.

  8. The Atlas of Submarine Glacial Landforms: Modern, Quaternary and Ancient

    Science.gov (United States)

    Dowdeswell, Julian A.; Canals, Miquel; Jakobsson, Martin; Todd, Brian J.; Dowdeswell, Evelyn K.; Hogan, Kelly A.

    2017-04-01

    Twenty years ago, the international marine community brought together a first Atlas of Acoustic Images of the high-latitude geo-marine environment (Davies et al. 1997). The present Atlas is a new attempt to summarize the state of knowledge of high-latitude glacier-influenced systems, focusing on HR imagery derived from multibeam swath bathymetry and novel 2D and 3D seismic reflection tools. These new-generation techniques, aided by accurate global positioning, have revolutionized the imaging of the seafloor and subseafloor over the past two decades and have now been deployed widely in polar and subpolar waters, providing vast quantities of new data. It is, therefore, timely to provide a compilation of the variety of submarine glacial and related landforms, together with their stratigraphic setting where possible, for scientific, technological, environmental and economic reasons. The glacial imprint on the modern seabed and palaeo-shelf surfaces, buried in glacial-sedimentary depocentres, can now be imaged better than ever before using the above techniques, providing novel insights into present and past environmental conditions and sedimentary architecture. The understanding of polar regions and their changing ice cover is of enhanced significance as they are both a key driver of global change and important responders to it. Finally, industry is increasingly interested on the dimensions and architecture of glacial sedimentary depocentres on present and past continental shelves because of the hydrocarbon potential of some glacial-sedimentary systems. The Atlas consists of a comprehensive series of over 180 contributions that describe, illustrate and discuss the full variability of landforms found on the high-latitude, glacier-influenced systems, and is organised in terms of their positions on a continental margin into those from: (1) fjords, (2) continental shelves and plateaus, and (3) the deep margin and basins beyond. The Atlas has been published by the Geological

  9. Potential Impact of Submarine Power Cables on Crab Harvest

    Science.gov (United States)

    Bull, A. S.; Nishimoto, M.

    2016-02-01

    Offshore renewable energy installations convert wave or wind energy to electricity and transfer the power to shore through transmission cables laid on or buried beneath the seafloor. West coast commercial fishermen, who harvest the highly prized Dungeness crab (Metacarcinus magister) and the rock crab (Cancer spp.), are concerned that the interface of crabs and electromagnetic fields (EMF) from these cables will present an electrified fence on the seafloor that their target resource will not cross. Combined with the assistance of professional fishermen, submarine transmission cables that electrify island communities and offshore oil platforms in the eastern Pacific provide an opportunity to test the harvest of crab species across power transmission cables. In situ field techniques give commercial crab species a choice to decide if they will cross fully energized, EMF emitting, power transmission cables, in response to baited traps. Each independent trial is either one of two possible responses: the crab crosses the cable to enter a trap (1) or the crab does not cross the cable to enter a trap (0). Conditions vary among sample units by the following categorical, fixed factors (i.e., covariates) of cable structure (buried or unburied); direction of cable from crab position (west or east, north or south); time and season. A generalized linear model is fit to the data to determine whether any of these factors affect the probability of crabs crossing an energized cable to enter baited traps. Additionally, the experimental design, aside from the number of runs (set of sample trials) and the dates of the runs, is the same in the Santa Barbara Channel for rock crab and Puget Sound for Dungeness crab, and allows us to compare the capture rates of the two species in the two areas. We present preliminary results from field testing in 2015.

  10. Anatomy of La Jolla submarine canyon system; offshore southern California

    Science.gov (United States)

    Paull, C.K.; Caress, D.W.; Lundsten, E.; Gwiazda, R.; Anderson, K.; McGann, M.; Conrad, J.; Edwards, B.; Sumner, E.J.

    2013-01-01

    An autonomous underwater vehicle (AUV) carrying a multibeam sonar and a chirp profiler was used to map sections of the seafloor within the La Jolla Canyon, offshore southern California, at sub-meter scales. Close-up observations and sampling were conducted during remotely operated vehicle (ROV) dives. Minisparker seismic-reflection profiles from a surface ship help to define the overall geometry of the La Jolla Canyon especially with respect to the pre-canyon host sediments. The floor of the axial channel is covered with unconsolidated sand similar to the sand on the shelf near the canyon head, lacks outcrops of the pre-canyon host strata, has an almost constant slope of 1.0° and is covered with trains of crescent shaped bedforms. The presence of modern plant material entombed within these sands confirms that the axial channel is presently active. The sand on the canyon floor liquefied during vibracore collection and flowed downslope, illustrating that the sediment filling the channel can easily fail even on this gentle slope. Data from the canyon walls help constrain the age of the canyon and extent of incision. Horizontal beds of moderately cohesive fine-grained sediments exposed on the steep canyon walls are consistently less than 1.232 million years old. The lateral continuity of seismic reflectors in minisparker profiles indicate that pre-canyon host strata extend uninterrupted from outside the canyon underneath some terraces within the canyon. Evidence of abandoned channels and point bar-like deposits are noticeably absent on the inside bend of channel meanders and in the subsurface of the terraces. While vibracores from the surface of terraces contain thin (< 10 cm) turbidites, they are inferred to be part of a veneer of recent sediment covering pre-canyon host sediments that underpin the terraces. The combined use of state of the art seafloor mapping and exploration tools provides a uniquely detailed view of the morphology within an active submarine canyon.

  11. Migration of hydrothermal systems in an evolving collisional orogen, New Zealand

    Science.gov (United States)

    Craw, D.; Upton, P.; Horton, T.; Williams, J.

    2013-02-01

    The Pacific-Australian tectonic plate boundary through the South Island of New Zealand consists of the transpressional Southern Alps mountain belt and the transcurrent Marlborough Fault System, both of which have active tectonically driven hydrothermal systems, with topographically driven meteoric incursion and warm springs. The Southern Alps hydrothermal system is relatively diffuse, with little or no fault control, and is channelled through scattered extensional sites beneath the mountains, where gold mineralisation is occurring locally. The hydrothermal activity along the Marlborough Fault System is controlled by the principal faults in well-defined valleys separated by narrow high ridges. Lateral evolution of Marlborough fault strands southwestwards into the Southern Alps has caused diversion of diffuse Southern Alps hydrothermal activity into the structural superimposition zone, where fluid flow is increasingly being controlled by faults. This hydrothermal diversion was accompanied by major topographic reorientation and river drainage reversal in the late Quaternary. Vein swarms now exposed in the remnants of the Southern Alps north of the superimposition zone formed at shallow levels, with some evidence for fluid boiling, from a mixture of meteoric and deep-sourced fluid. These veins, some of which contain gold, are part of an abandoned lateral incursion of the Marlborough fault strands. Observations on this active plate boundary provide some insights into processes that controlled orogenic gold mineralisation in ancient belts, particularly with respect to relationships between hydrothermal fluid flow, structure and topography.

  12. Polyphase Neoproterozoic orogenesis within the east Africa- Antarctica orogenic belt in central and northern Madagascar

    Science.gov (United States)

    Key, R.M.; Pitfield, P.E.J.; Thomas, Ronald J.; Goodenough, K.M.; Waele, D.; Schofield, D.I.; Bauer, W.; Horstwood, M.S.A.; Styles, M.T.; Conrad, J.; Encarnacion, J.; Lidke, D.J.; O'connor, E. A.; Potter, C.; Smith, R.A.; Walsh, G.J.; Ralison, A.V.; Randriamananjara, T.; Rafahatelo, J.-M.; Rabarimanana, M.

    2011-01-01

    Our recent geological survey of the basement of central and northern Madagascar allowed us to re-evaluate the evolution of this part of the East Africa-Antarctica Orogen (EAAO). Five crustal domains are recognized, characterized by distinctive lithologies and histories of sedimentation, magmatism, deformation and metamorphism, and separated by tectonic and/or unconformable contacts. Four consist largely of Archaean metamorphic rocks (Antongil, Masora and Antananarivo Cratons, Tsaratanana Complex). The fifth (Bemarivo Belt) comprises Proterozoic meta-igneous rocks. The older rocks were intruded by plutonic suites at c. 1000 Ma, 820-760 Ma, 630-595 Ma and 560-520 Ma. The evolution of the four Archaean domains and their boundaries remains contentious, with two end-member interpretations evaluated: (1) all five crustal domains are separate tectonic elements, juxtaposed along Neoproterozoic sutures and (2) the four Archaean domains are segments of an older Archaean craton, which was sutured against the Bemarivo Belt in the Neoproterozoic. Rodinia fragmented during the early Neoproterozoic with intracratonic rifts that sometimes developed into oceanic basins. Subsequent Mid- Neoproterozoic collision of smaller cratonic blocks was followed by renewed extension and magmatism. The global 'Terminal Pan-African' event (560-490 Ma) finally stitched together the Mid-Neoproterozoic cratons to form Gondwana. ?? The Geological Society of London 2011.

  13. Physics teaching in the medical schools of Taiwan

    OpenAIRE

    Hsu, Jiann-wien; Hsu, Roy

    2012-01-01

    We describe and analyze the statistics of general physics and laboratory courses in the medical schools of Taiwan. We explore the development of the general physics curriculum for medical students of Taiwan. Also, an approach to designing a general physics course in combination with its application to medical sciences is proposed. We hope this preliminary study can provide a useful reference for physics colleagues in the medical schools of Taiwan to revolutionize the dynamics of teaching phys...

  14. Scattering effect of submarine hull on propeller non-cavitation noise

    Science.gov (United States)

    Wei, Yingsan; Shen, Yang; Jin, Shuanbao; Hu, Pengfei; Lan, Rensheng; Zhuang, Shuangjiang; Liu, Dezhi

    2016-05-01

    This paper investigates the non-cavitation noise caused by propeller running in the wake of submarine with the consideration of scattering effect caused by submarine's hull. The computation fluid dynamics (CFD) and acoustic analogy method are adopted to predict fluctuating pressure of propeller's blade and its underwater noise radiation in time domain, respectively. An effective iteration method which is derived in the time domain from the Helmholtz integral equation is used to solve multi-frequency waves scattering due to obstacles. Moreover, to minimize time interpolation caused numerical errors, the pressure and its derivative at the sound emission time is obtained by summation of Fourier series. It is noted that the time averaging algorithm is used to achieve a convergent result if the solution oscillated in the iteration process. Meanwhile, the developed iteration method is verified and applied to predict propeller noise scattered from submarine's hull. In accordance with analysis results, it is summarized that (1) the scattering effect of hull on pressure distribution pattern especially at the frequency higher than blade passing frequency (BPF) is proved according to the contour maps of sound pressure distribution of submarine's hull and typical detecting planes. (2) The scattering effect of the hull on the total pressure is observable in noise frequency spectrum of field points, where the maximum increment is up to 3 dB at BPF, 12.5 dB at 2BPF and 20.2 dB at 3BPF. (3) The pressure scattered from hull is negligible in near-field of propeller, since the scattering effect surrounding analyzed location of propeller on submarine's stern is significantly different from the surface ship. This work shows the importance of submarine's scattering effect in evaluating the propeller non-cavitation noise.

  15. Simple models for the simulation of submarine melt for a Greenland glacial system model

    Science.gov (United States)

    Beckmann, Johanna; Perrette, Mahé; Ganopolski, Andrey

    2018-01-01

    Two hundred marine-terminating Greenland outlet glaciers deliver more than half of the annually accumulated ice into the ocean and have played an important role in the Greenland ice sheet mass loss observed since the mid-1990s. Submarine melt may play a crucial role in the mass balance and position of the grounding line of these outlet glaciers. As the ocean warms, it is expected that submarine melt will increase, potentially driving outlet glaciers retreat and contributing to sea level rise. Projections of the future contribution of outlet glaciers to sea level rise are hampered by the necessity to use models with extremely high resolution of the order of a few hundred meters. That requirement in not only demanded when modeling outlet glaciers as a stand alone model but also when coupling them with high-resolution 3-D ocean models. In addition, fjord bathymetry data are mostly missing or inaccurate (errors of several hundreds of meters), which questions the benefit of using computationally expensive 3-D models for future predictions. Here we propose an alternative approach built on the use of a computationally efficient simple model of submarine melt based on turbulent plume theory. We show that such a simple model is in reasonable agreement with several available modeling studies. We performed a suite of experiments to analyze sensitivity of these simple models to model parameters and climate characteristics. We found that the computationally cheap plume model demonstrates qualitatively similar behavior as 3-D general circulation models. To match results of the 3-D models in a quantitative manner, a scaling factor of the order of 1 is needed for the plume models. We applied this approach to model submarine melt for six representative Greenland glaciers and found that the application of a line plume can produce submarine melt compatible with observational data. Our results show that the line plume model is more appropriate than the cone plume model for simulating

  16. Submarine geology and geomorphology of active Sub-Antarctic volcanoes: Heard and McDonald Islands

    Science.gov (United States)

    Watson, S. J.; Coffin, M. F.; Whittaker, J. M.; Lucieer, V.; Fox, J. M.; Carey, R.; Arculus, R. J.; Bowie, A. R.; Chase, Z.; Robertson, R.; Martin, T.; Cooke, F.

    2016-12-01

    Heard and McDonald Islands (HIMI) are World Heritage listed sub-Antarctic active volcanic islands in the Southern Indian Ocean. Built atop the Kerguelen Plateau by Neogene-Quaternary volcanism, HIMI represent subaerial exposures of the second largest submarine Large Igneous Province globally. Onshore, processes influencing island evolution include glaciers, weathering, volcanism, vertical tectonics and mass-wasting (Duncan et al. 2016). Waters surrounding HIMI are largely uncharted, due to their remote location. Hence, the extent to which these same processes shape the submarine environment around HIMI has not been investigated. In early 2016, we conducted marine geophysical and geologic surveys around HIMI aboard RV Investigator (IN2016_V01). Results show that volcanic and sedimentary features prominently trend east-west, likely a result of erosion by the eastward flowing Antarctic Circumpolar Current and tidal currents. However, spatial patterns of submarine volcanism and sediment distribution differ substantially between the islands. >70 sea knolls surround McDonald Island suggesting substantial submarine volcanism. Geophysical data reveals hard volcanic seafloor around McDonald Island, whereas Heard Island is characterised by sedimentary sequences tens of meters or more thick and iceberg scours - indicative of glacial processes. Differences in submarine geomorphology are likely due to the active glaciation of Heard Island and differing rock types (Heard: alkali basalt, McDonald: phonolite), and dominant products (clastics vs. lava). Variations may also reflect different magmatic plumbing systems beneath the two active volcanoes (Heard produces larger volumes of more focused lava, whilst McDonald extrudes smaller volumes of more evolved lavas from multiple vents across the edifice). Using geophysical data, corroborated with new and existing geologic data, we present the first geomorphic map revealing the processes that shape the submarine environment around HIMI.

  17. Fault linkages and activities in a transition zone of compression to transpression in Hsinchu area, northwestern Taiwan based on 3-D structural geometry

    Science.gov (United States)

    Huang, H.; Hu, J.; Huang, S.; Huang, C.

    2010-12-01

    The Taiwan orogenic belt is resulted from the convergence between Philippine Sea plate and Eurasian plate. Serious earthquakes occurred in west and northwest flanks of main mountain belt of the island in 1935 and 1999, caused more than 5000 deaths in total. In addition, Hsinchu Science and Industrial Park (HSIP) located in northwest Taiwan is one of the world's most important areas for semiconductor manufacturing. There are more than 400 technology companies in this park, and accounted for 10% of Taiwan's GDP. Consequently, active Hsincheng and Hsinchu faults in study area become the major threat of the industrial park, thus the understanding of complex subsurface seismogenic structures are crucial issue of earthquake hazard assessment and mitigation in Hsinchu area. Several geological cross sections have been constructed and discussed to suggest possible deep structures of these two major faults in previous study. However, how subsurface fault system and folding intersect still remains unclear and the evolution of fault and fold geometry in Hsinchu area is not fully understood. The main purpose of this study is to clarify the spatial linkage between the major thrust faults, folds, and adjacent transverse structures. In this study, we first construct the NW-SE trending cross-section which is sub-parallel to the regional shortening direction, and then balance this cross section to derive the structure evolution in Hsinchu area. We also incorporate several cross-sections and relocated seismicity to get detail 3D fault geometry for the numerical modeling in order to assess the interseismic strain accumulation and seismic potential based on geodetic measurements.

  18. Extensional flow produces recumbent folds in syn-orogenic granitoids (Padrón migmatitic dome, NW Iberian Massif)

    Science.gov (United States)

    Fernández, Rubén Díez; Parra, Luis Miguel Martín; Rubio Pascual, Francisco J.

    2017-04-01

    This contribution provides a case example on the generation of large-scale recumbent folds in syn-orogenic granitoids. We analyze the progressive reworking of extension-related structures into later ones after a period of crustal thickening. The Padrón migmatitic dome formed after the climax of the Gondwana-Laurussia collision in the late Paleozoic. Petrostructural analysis carried out in the eastern flank of this dome reveals that extensional flow resulted in progressive exhumation of mainland Gondwana, which rested under peri-gondwanan allochthonous terranes and a suture zone during maximum crustal thickening. Exhumation proceeded up to upper crust levels (andalusite stability field) along with partial melting of the middle-lower crust and with the generation of granitoid laccoliths during an early extensional stage. Newly-formed lithological and mechanical anisotropies, such as the presence of variably-sized sheet-shaped bodies of syn-orogenic granitoids, provided a favorable rheological setting for fold nucleation during the intermediate stages of extension. In extending orogenic crust, whether recumbent folds occur after significant melt production depends on the lateral/vertical flow ratio, and on the orientation of deforming bodies with regard to kinematic/strain axes. We suggest that subhorizontal extensional flow dominated over vertical flow during the early and intermediate stages of the evolution of the Padrón dome. A component of vertical (diapiric) flow caused progressive tilting of the sheet-like bodies and obliquity respect to strain axes. This resulted in the development of regional-scale folds at the expense of syn-orogenic granitoids, such as in the case of the Portomouro recumbent synform. Extensional ductile flow was oblique to the trend of the orogen during the whole process, and directed to the NNW during the formation of recumbent folds. Non-coaxial shearing favored an (NNW-SSE) elongate shape for the syn-kinematic granitic massifs as well

  19. Controlling factors of spatial and temporal preservation of the geochronological signal in sediments during an orogenic cycle

    Science.gov (United States)

    Rat, Juliette; Mouthereau, Frédéric; Bernet, Matthias; Brichau, Stéphanie; Balvay, Mélanie; Garzanti, Eduardo; Ando, Sergio

    2017-04-01

    Detrital content of sediments preserved in basins provide constraints on the nature of source rocks, dynamics of sediment transport, and potentially on tectonics and climate changes. U-Pb dating method on detrital zircon is ideally suited for provenance studies due to the ability of U-Pb age data to resist several orogenic cycles. However, with the aim to track sediment source evolution over a single orogenic cycle and determine characteristic time and parameters controlling the geochronological signal preservation throughout the cycle from rifting, mountain building to post-collision evolution, low-temperature thermochronology combined with sediment petrography are more appropriate than the U-Pb dating approach taken alone. To better understanding processes at play in the long-term geochronological signal preservation we focus on the sediment record associated with the Iberia plate tectonic evolution, which is part of the OROGEN research project, co-financed by BRGM, TOTAL & CNRS. The Iberian plate recorded a period of extension in the Late Jurassic, followed during the Early Cretaceous (Aptian-Albian) by a major thinning event documented by thick syn-rift sediments in intraplate basins and plate-scale heating/cooling of the Iberia crust, as argued by published fission track ages. Paleogeographic reconstructions that are based on stratigraphic and lithofacies analyses in northern Iberia (Iberian Range, Pyrenees and Basque-Cantabrians Range), describe a large domain of continental/fluvial and shallow-marine siliciclastic deposition. The related detrital content was then recycled during the subsequent Pyrenean orogenic phase in the Ebro foreland basin, and eventually transfer to the Mediterranean realm during post-orogenic re-excavation of the Ebro basin. In this study, we complete the published time-temperature paths in the mesozoic syn-rift basins by providing new thermo-chronological analyses of well-dated syn-collision and post-collision stratigraphic sections

  20. Molluscan fauna of Gueishan Island, Taiwan.

    Science.gov (United States)

    Huang, Chih-Wei; Hsiung, Ta-Wei; Lin, Si-Min; Wu, Wen-Lung

    2013-01-01

    This dataset records the occurrence and inventory of molluscan fauna on Gueishan Island, the only active volcanic island in Taiwan, based on the literature survey and field investigation conducted between 2011 and 2012. The literature review involved seven studies published from 1934 to 2003, which collectively reported 112 species from 61 genera and 37 families of Mollusca on Gueishan Island. Through our field investigation, we identified 34 species from 28 genera and 23 families. Fourteen of these species were new records on Gueishan Island: Liolophura japonica, Lottia luchuana, Nerita costata, Nerita rumphii, Diplommatina suganikeiensis, Littoraria undulata, Solenomphala taiwanensis, Assiminea sp., Siphonaria laciniosa, Laevapex nipponica, Carychium hachijoensis, Succinea erythrophana, Zaptyx crassilamellata, and Allopeas pyrgula. In Total, there are 126 species from 71 genera and 45 families of Mollusca on Gueishan Island. These data have been published through GBIF [http://taibif.org.tw/ipt/resource.do?r=gueishan_island] and integrated into the Taiwan Malacofauna Database (http://shell.sinica.edu.tw/).

  1. Health and environmental risk assessment associated with a potential recovery of the Russian submarine K-27

    Energy Technology Data Exchange (ETDEWEB)

    Hosseini, A.; Amundsen, I.; Brown, J.E.; Dowdall, M.; Standring, W. [Norwegian Radiation Protection Authority/CERAD CoE (Norway); Bartnicki, J. [Norwegian Meteorological Institute/CERAD CoE (Norway); Karcher, M. [O.A.Sys - Ocean Atmosphere Systems GmbH (Germany); Lind, O.C.; Salbu, B. [Norwegian University of Life Sciences/CERAD CoE (Norway)

    2014-07-01

    The nuclear submarine K-27 is one of several objects with spent nuclear fuel (SNF) which has been dumped in the Arctic. It contained two liquid metal reactors (LMRs) of 70 MW maximum thermal power each and used Pb-Bi as the coolant. The reactors were loaded with 180 kg of U-235 at an enrichment of 90 %. In September 1981, the submarine was sunk in the shallow waters of Stepovoy Fjord at an estimated depth of 30 m. Concerns have been expressed by various parties regarding the issue of dumped nuclear waste in the Kara Sea and in particular the submarine K-27. To address these concerns and to provide a better basis for evaluating possible radiological impact (especially as a consequence of a potential recovery of the submarine), an environmental impact assessment has been undertaken. The study is based on construction of different hypothetical accident scenarios and evaluating possible associated consequences for human and the environment. In general, three main scenarios seem probable and thus appropriate for consideration. One is the 'zero- alternative', i.e. investigate the current and future impact assuming no interventions. The second considers an accidental scenario involving the raising of the submarine and the third an accidental scenario related to the transportation of the submarine to shore for defueling. With regards to the accidental scenarios related to raising and transportation of the submarine, two alternatives can be considered depending on where and how a hypothetical accident will take place and whether the subsequent releases occur under water or at the water surface. The issue of an uncontrolled chain reaction occurring as a result of a potential recovery of the submarine will be included in the assessment. The work includes application of state of the art 3D hydrodynamic and atmospheric dispersion models to investigate the transport, distribution and fate of relevant radionuclides following a hypothetical accident in aquatic and

  2. Nuclear-powered submarine accidents; Les accidents de sous-marins nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Tournyol du Clos, A.

    1996-04-01

    Most of nuclear-powered ships are military ships and submarines represent 95% of the total. Most of the propulsion reactors used are of PWR type. This paper gives the principal technical characteristics of PWR ship propulsion reactors and the differences with their civil homologues. The principal accidents that occurred on US and Russian nuclear-powered submarines are also listed and the possible effects of a shipwreck on the reactor behaviour are evaluated with their environmental impact. (J.S.). 1 tab., 1 photo.

  3. Modeling and Synthesis Methods for Retrofit Design of Submarine Actuation Systems. Energy Storage for Electric Actuators

    Science.gov (United States)

    2011-12-15

    sternplane v - sway w - heave u - surge X Y Z y z x Figure 2: Coordinate frame definitions of submarine vehicular dynamics. 2.1 Six Degree of Freedom...where Mν̇ is the total inertial matrix, C(ν) is the Coriolis/centripetal matrix, D(ν) is the total damping matrix, g(η) are the buoyancy and weight...Natick, MA. Retrofit Design of Submarine Actuation Systems Page 7 q - pitch w - heave u - surge δs Msp Figure 3: Hydrodynamic moment unit definition

  4. The impact of the Type 094 ballistic missile submarine on China's nuclear policy

    OpenAIRE

    Bell, Samuel D.

    2009-01-01

    Approved for public release, distribution unlimited This thesis examines the implication of China’s near completion of a viable nuclear triad. The objective is to determine first, how this submarine will fit into China’s no-first-use policy with regards to their nuclear weapons. And second, determine how advanced this weapon platform will be. With the introduction of multiple Type 094 “Jin” class ballistic missile submarines, has Beijing set the stage for a possible return to Cold War leve...

  5. Oceanographic studies supporting the assessment of deep-sea disposal of defueled decommissioned nuclear submarines

    Science.gov (United States)

    Ross Heath, G.; Rea, David K.; Ness, Gordon; Dale Pillsbury, R.; Beasley, Thomas M.; Lopez, Carlos; Talbert, Daniel M.

    1984-12-01

    Based on criteria developed by the international Atomic Energy Agency (IAEA), potential disposal sites for defueled, decommissioned nuclear submarines appear to exist in deep water south of the Mendocino Fracture Zone within 200 nautical miles of the United States Oceanographic measurements in the water column and at the sea floor in a study area (W-N) at 39 5°N, 127 5°W will allow the operational and radiological consequences of deep-sea disposal to be compared with land burial of old submarines. The W-N studies also are yielding new data that will provide insights to the deposition and early diagenesis of distal hemipelagic sediments

  6. Physics teaching in the medical schools of Taiwan.

    Science.gov (United States)

    Hsu, Jiann-wien; Hsu, Roy

    2012-02-01

    We describe and analyze the statistics of general physics and laboratory courses in the medical schools of Taiwan. We explore the development of the general physics curriculum for medical students of Taiwan. Also, an approach to designing a general physics course in combination with its application to medical sciences is proposed. We hope this preliminary study can provide a useful reference for physics colleagues in the medical schools of Taiwan to revolutionize the dynamics of teaching physics to the medical students of Taiwan. Copyright © 2011. Published by Elsevier B.V.

  7. [Achievements in anatomy education by Dr. Otto Mori in Taiwan].

    Science.gov (United States)

    Mori, Chisato

    2008-12-01

    My grandfather, Otto Mori (1980-1967) was one of the founders of anatomy education in Japan from 1940s to 1960s. While he was the director of Department of Medicine of Taipei Imperial University, he made efforts to establish the medical and anatomical education in Taiwan. Introduction of the achievement of anatomy education in Taiwan is important to know the history of anatomy education in Japan. I visited Taiwan National University (former Taipei Imperial University) in 2005, which was 60 years after Otto Mori started his life as a professor in Taiwan, and 110 years after Rintaro (Ogai) Mori, my great-grandfather stayed shortly in Taiwan after Japan-China War. After the World War II, there has been very few opportunity of communication between anatomy labs of Taiwan and Japan. In Taiwan, more than 70 years ago, Japanese style anatomy education was established, however, after the WW II, they learned education style from the U.S. Chiba University exchange "sister universities" agreement between National Taiwan University in 2007, and started exchange communication regarding anatomy education and scientific research. It is meaningful to learn from excellent education system of old Japan when we communicate with National Taiwan University.

  8. Socially Engaged Buddhist Nuns: Activism in Taiwan and North America

    Directory of Open Access Journals (Sweden)

    Karma Lekshe Tsomo

    2015-02-01

    Full Text Available The last decades of the twentieth century have been a time of new visibility and social activism for Buddhists in Taiwan and around the world. This paper compares the social engagement of nuns in the Chinese Buddhist tradition in Taiwan and North America. I would like to argue that whereas nuns in Taiwan have developed a variety of approaches to social involvement, their counterparts in the Chinese diaspora in North America have had to face a set of challenges specific to overseas Chinese communities in addition to Chinese Buddhist tradition. The article concludes with reflections on the prospects for nuns' social activism in Taiwan and North America in future years.

  9. Taiwan in 2004: Elections, Referenda, and Other Democratic Challenges

    National Research Council Canada - National Science Library

    Dumbaugh, Kerry

    2005-01-01

    .... In both the presidential and legislative election campaigns, Chen emphasized gaining a separate international identity for Taiwan -- an emphasis to which Beijing strenuously objected as dangerously...

  10. Ethnic politics and democratic transition in Taiwan

    OpenAIRE

    Wang, Fu-chang

    2013-01-01

    Ethnic politics issues were usually seen as playing little role in Taiwan’s democratizationtransition. This underestimation not only limits the explanatory power of current theories of Taiwan’s democratization, but it also distorts our understandings of the cause, nature, and prospects of ethnic conflicts in a democratic system, especially in the case of Taiwan. By proposing a different way of analyzing ethnic politics issues, this paper demonstrates the critical role of ethnic politics in Ta...

  11. The Study of Counterterrorism Mechanisms in Taiwan

    Science.gov (United States)

    2013-12-01

    Attacks on the U.S. National Security Policy” (master’s thesis, Feng Chia University, 2004). 20 U. S. Department of State, Patterns of Global Terrorism...After the 911 incident, the Taiwan Government took immediate response measures and started the National Security mechanism. President Chen Shui -bian...Security Policy.” Master’s thesis, Feng Chia University, 2004. Cai, Tingrong. “The Law Challenges of Counterterrorism-From the Perspective of Human

  12. Transformation of Taiwan’s Reserve Force

    Science.gov (United States)

    2017-01-01

    concerned only with preserving its security and maintaining its democratically elected government.6 Taiwan can achieve its strategic objective by...force represents a significant strategic means for achieving Taipei’s objective to deter PRC use of force against the island. As the Summary xi...definition of strategy as “a plan for applying means to achieve ends in a competitive interaction involving the threat or actual use of force.”1

  13. FORENSIC DEVELOPMENT AND CONTRIBUTION OF TAIWAN

    OpenAIRE

    PU, Chang En

    2017-01-01

    Taiwan forensicscience laboratory system was started from police department under Ministry ofInterior Affairs in 1945, then the labs under Ministry of Justice was developedfrom 1956, and till 1997 the traditionally complete system was developedincluding medical examiner system, toxicology, forensic chemistry, forensicbiology, Questioned document examination, Polygraph, Speaker identification,etc. In 2006, the first Cyber forensic lab was established, by then labs neededfor modern society were...

  14. Submarine landslide triggered by eruption recorded by in-situ hydrophone at NW Rota-1 submarine volcano, Mariana Arc (Invited)

    Science.gov (United States)

    Chadwick, B.; Dziak, R. P.; Embley, R. W.; Tunnicliffe, V.; Sherrin, J.; Cashman, K. V.; Deardorff, N.

    2010-12-01

    An expedition to NW Rota-1, Mariana Arc, in March 2010 with R/V Kilo Moana and ROV Jason found that the submarine volcano (summit depth 520 m) was still erupting more or less continuously as has been observed since 2004, In addition, the expedition also discovered that a major landslide had occurred since the last visit in April 2009, demonstrating the dynamic processes of eruption, collapse, and regrowth in the submarine arc environment. The dive observations reveal the responses of the volcano’s magmatic and hydrothermal systems to such a collapse, as well as how the resident chemosynthetic biological community has responded to the event. The morphologic changes from the landslide can be quantified by comparing multibeam bathymetric surveys between 2009 and 2010. The headwall of the slide is now ~100 m north of the former summit ridge where depth changes up to -90 m occurred between surveys. The slide excavated material from the upper southern slope of the volcano to a distance of 3.5 km downslope, and deposited material between 2-8 km from the summit down to at least 2800 m on the volcano flank. The area and volume of slide deposits (positive depth changes) are 7.1 x 106 m2 and 5.3 x 107 m3, respectively, and the maximum thickness is +42 m. The area and volume of material removed by the slide (negative depth changes) are 2.2 x 106 m2 and -4.1 x 107 m3, respectively. We have found no evidence for a local tsunami generated by this event. The changes in morphology near the summit show that the landslide primarily removed loose volcaniclastic deposits that had accumulated near the active eruptive vent, exposing an underlying stock-like core of resistant intrusive rocks and massive lavas at the summit. During March 2010, there were at least 5 active eruptive vents, located along a line 200-m long, that changed between active and inactive day-to-day and even hour-to-hour, suggesting that the near-surface magmatic plumbing system was still reorganizing after the

  15. Towards Marine Spatial Planning in Southern Taiwan

    Directory of Open Access Journals (Sweden)

    Meng-Tsung Lee

    2014-11-01

    Full Text Available Due to population growth, rapid economic development and inadequate marine control, the use of ocean and coastal regions in Taiwan has become more frequent and intense in recent years. However, the lack of comprehensive marine and coastal planning in this island nation has led to many conflicts over space and resources and limited its ability to prepare for and respond to environmental hazards, thus threatening national security as well as the safety and property of its citizens. This study proposes a marine zoning scheme for southern Taiwan. The results show that many important habitats in the southern sea areas have not been properly protected due to the extremely small size of the marine protected area. Furthermore, the majority of the conflicts derive from the exclusive fishing right vs. other uses such as marine conservation. Therefore, it is crucial to establish the marine spatial planning (MSP for the Southern Taiwan to deal with the conflicts of use seas and uncertainties associated with complex, heterogeneous, and dynamic marine system.

  16. Predictors of Burnout Among Nurses in Taiwan.

    Science.gov (United States)

    Lee, Huan-Fang; Yen, Miaofen; Fetzer, Susan; Chien, Tsair Wei

    2015-08-01

    Nurse burnout is a crucial issue for health care professionals and impacts nurse turnover and nursing shortages. Individual and situational factors are related to nurse burnout with predictors of burnout differing among cultures and health care systems. The predictors of nurse burnout in Asia, particularly Taiwan, are unknown. The purpose of this study was to investigate the predictors of burnout among a national sample of nurses in Taiwan. A secondary data analysis of a nationwide database investigated the predictors of burnout among 1,846 nurses in Taiwan. Hierarchical regression analysis determined the relationship between predictors and burnout. Predictors of Taiwanese nurse burnout were age, physical/psychological symptoms, job satisfaction, work engagement, and work environment. The most significant predictors were physical/psychological symptoms and work engagement. The variables explained 35, 39, and 18 % of the emotional exhaustion, personal accomplishment, and depersonalization variance for 54 % of the total variance of burnout. Individual characteristics and nurse self-awareness, especially work, engagement can impact Taiwanese nurses' burnout. Nurse burnout predictors provide administrators with information to develop strategies including education programs and support services to reduce nurse burnout.

  17. Transformation of Taiwan's Upper Secondary Education System

    Directory of Open Access Journals (Sweden)

    Hueih-Lirng Laih

    1998-09-01

    Full Text Available This paper explores the policy issues circling around the structural "transition" in upper secondary education implicit in the twenty-year increase in secondary and third-level school enrollment rates in Taiwan. This expansion has taken place within a secondary school system which is rigidly divided into both general, i.e., academic, and vocational tracks and into public and private sectors: the majority of students are enrolled in the private vocational sector which is only loosely articulated with the university sector. These features of the school system are analysed against the background of social and economic developments in Taiwan as well as public opinion. The analysis suggests that the present structures of school must be "reformed" in ways that will result in a more unified secondary system with both greater public funding and better articulation of all school types with the third level. The policy options that circle around the possibility of such reforms in the areas of curriculum, examination structures and second level-third level articulation are discussed and a policy framework for the reform of the Taiwan secondary education sector is outlined.

  18. Historical Overview of Taenia asiatica in Taiwan

    Science.gov (United States)

    Ho, Chau-Mei; Chung, Wen-Cheng

    2013-01-01

    An overview of the epidemiological, biological, and clinical studies of Taenia and taeniasis in Taiwan for the past century is presented. The phenomenal observations that led to the discovery of Taenia asiatica as a new species, which differ from Taenia solium and Taenia saginata, are described. Parasitological surveys of the aborigines in Taiwan revealed a high prevalence of taeniasis, which might be due to the culture of eating raw liver of hunted wild boars. Chemotherapeutic deworming trials involving many patients with taeniasis were discussed. Praziquantel was found to be very effective, but sometimes complete worms could not be recovered from the feces after treatment, probably due to the dissolution of the proglottids. Atabrine, despite some side effects, can still be used, in properly controlled dosages, as the drug of choice for human T. asiatica infection if we need to recover the expelled worms for morphological examinations. Research results on the infection of T. asiatica eggs from Taiwan aborigines in experimental animals were also noted. Since the pig serve as the natural intermediate host of T. asiatica and the predilection site is the liver, a differential comparison of other parasitic pathogens that might cause apparently similar lesions is also presented. PMID:23467308

  19. [Health networks for new immigrants in taiwan].

    Science.gov (United States)

    Yen, Fang-Tzu; Wu, Huei-Min

    2014-08-01

    Healthcare and studies related to new immigrants in Taiwan have been influenced by immigrant reproductive health management policy. Some nursing scholars have criticized the top-down approach as potentially not addressing the actual healthcare needs of these immigrants. Medical institutions are being called upon to provide culturally appropriate care. Using health networks as its conceptual framework, this paper explores the definition of health as perceived by recent immigrants to Taiwan and their perspectives on seeking and maintaining health. This paper uses participant observation and depth-interviews to assess how recent immigrants from Mainland China, Vietnam, and Indonesia seek health in their new homeland, evaluate the differences between the healthcare systems in their former and current countries, and recommend actions necessary to ensure the health and wellbeing of this population. The findings are grouped into three themes: "the differences between immigrants and Taiwanese in health care," "local health networks", and "transnational health networks." These themes reflect the views on health and health care of recent female immigrants to Taiwan. Through the actions and narratives of these immigrants, this paper suggests the priority concerns that immigrant agencies should address in order to maintain the health of this group. Additionally, findings give some insight into the gender and ethnic characteristics of immigrant health networks. Immigrants construct and rely upon social relations, cultural identity, and resources to maintain their wellbeing. This study contributes to transcultural nursing theory and to in-service training and helps medical practitioners and nurses provide culturally appropriate care.

  20. Bone health among older adults in Taiwan.

    Science.gov (United States)

    Wang, Wei-Jen; Kuo, Kuan-Liang; Liaw, Chen-Kun; Wu, Tai-Yin; Chie, Wei-Chu; Chen, Jer-Min

    There has been much discussion about the risk factors for osteoporosis, but studies involving elderly population in Taiwan are minimal. We aimed to describe variables related to osteoporosis among community dwelling older people in Taiwan. This is a cross-sectional study. The 671 participants were randomly selected from 3680 examinees of the annual Senior Citizens Health Examination in year 2010. Participants were interviewed with a detailed questionnaire, and 91 of them were invited for dual-energy X-ray absorptiometry (DXA). Predictor variables included age, gender and clinical risk factors for osteoporosis. The main outcome was osteoporosis confirmed by DXA. The mean age of the participants was 75.7±6.4years old. Overall, the most prevalent variables for osteoporosis were height loss in adulthood (41.0%), lack of dairy products or calcium supplements (32.0%) and insufficient physical activity (10.4%). In multivariate models, we found that underweight (OR=9.80) and lack of dairy products/calcium supplements (OR=3.68) were the main variables for osteoporosis. In the subgroup analysis involving only women, underweight (OR=14.60) was the main variable. Among community-dwelling older people in Taiwan, osteoporosis was mainly associated with underweight and lack of dairy products or calcium supplements. We suggest using the key questions of underweight and dietary pattern in clinical settings to identify high risk people who are candidates for further BMD exam. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Swath sonar mapping of Earth's submarine plate boundaries

    Science.gov (United States)

    Carbotte, S. M.; Ferrini, V. L.; Celnick, M.; Nitsche, F. O.; Ryan, W. B. F.

    2014-12-01

    The recent loss of Malaysia Airlines flight MH370 in an area of the Indian Ocean where less than 5% of the seafloor is mapped with depth sounding data (Smith and Marks, EOS 2014) highlights the striking lack of detailed knowledge of the topography of the seabed for much of the worlds' oceans. Advances in swath sonar mapping technology over the past 30 years have led to dramatic improvements in our capability to map the seabed. However, the oceans are vast and only an estimated 10% of the seafloor has been mapped with these systems. Furthermore, the available coverage is highly heterogeneous and focused within areas of national strategic priority and community scientific interest. The major plate boundaries that encircle the globe, most of which are located in the submarine environment, have been a significant focus of marine geoscience research since the advent of swath sonar mapping. While the location of these plate boundaries are well defined from satellite-derived bathymetry, significant regions remain unmapped at the high-resolutions provided by swath sonars and that are needed to study active volcanic and tectonic plate boundary processes. Within the plate interiors, some fossil plate boundary zones, major hotspot volcanoes, and other volcanic provinces have been the focus of dedicated research programs. Away from these major tectonic structures, swath mapping coverage is limited to sparse ocean transit lines which often reveal previously unknown deep-sea channels and other little studied sedimentary structures not resolvable in existing low-resolution global compilations, highlighting the value of these data even in the tectonically quiet plate interiors. Here, we give an overview of multibeam swath sonar mapping of the major plate boundaries of the globe as extracted from public archives. Significant quantities of swath sonar data acquired from deep-sea regions are in restricted-access international archives. Open access to more of these data sets would

  2. Submarine Groundwater Discharge in Stony Brook Harbor, NY

    Science.gov (United States)

    Durand, J. M.; Young, C.; Wong, T.; Hanson, G. N.

    2012-12-01

    As nutrients can significantly impact coastal ecosystems, understanding their path to embayments and oceans is crucial. In Stony Brook Harbor (Long Island, NY), submarine groundwater discharge (SGD) is the only significant contribution of freshwater and thus constitutes the main pathway for nutrients, which may eventually reach Long Island Sound. Subterranean estuaries have been shown to be highly reactive zones where nitrogen attenuation can occur. Understanding the fate of nitrogen in Stony Brook Harbor requires knowing the volume of groundwater entering the bay as well as the amount of denitrification, in the context of the hydrogeological framework. This is achieved by combining electrical resistivity survey, water sampling in piezometers, point conductivity and seepage measurements. A Trident probe inserted 60 cm deep into the sediments allows measuring the conductivity and temperature of the sediments and the overlying seawater. In spring 2011, five Trident transects spreading across the head of the harbor were used as a preliminary study to reveal potential locations for SGD. Locations with significant difference between sediment and seawater temperature and/or conductivities were further investigated using an AGI SuperSting 8-channel receiver resistivity meter. Two ultrasonic seepage meters were deployed in May and July 2011 about 20 m below the low tide mark. Five piezometers were aligned parallel to one resistivity survey. Our resistivity data indicate superficial mixing in the intertidal zone. The freshwater extends quite far under the seafloor, above 67 meters after the low tide mark for one location. The freshwater/saltwater interface seems to be almost horizontal. The piezometer data agree relatively well with the resistivity data. The preliminary average seepage rates observed vary from 3 to 60 cm/d. The resistivity sections reveal the presence of a thin layer of high conductivity above the low tide mark. This matches the observation of a superficial

  3. Experimental research on the double-peak characteristic of underwater radiated noise in the near field on top of a submarine

    Science.gov (United States)

    Liu, Ning; Wang, Sande; Guo, Tao; Li, Xiyou; Yu, Ziyang

    2011-06-01

    The double-peak characteristic of underwater radiated noise in the near field on top of the target submarine was analyzed in depth on the basis of submarine test data on the sea. The contribution of three major noise sources to the radiated noise of a submarine were compared and analyzed, and emphasis was put on the original source, production mechanism, and their correlative characteristics. On the basis of analysis on underwater tracking and pass through characteristics of the target submarine, the double-peak phenomenon was reasonably interpreted. Furthermore, the correctness of the theoretical interpretation was verified adequately in real submarine tests. The double-peak phenomenon indicates that the space distributing character on submarine radiated noise are both asymmetrical with time and space, whereas that is provided with directivity. Studying the double-peak phenomenon in depth has important reference value and meaning in engineering practice for understanding the underwater radiated noise field of submarines.

  4. Cratons and orogenic belts of the Brazilian Shield and their contained gold deposits

    Science.gov (United States)

    Hartmann, Leó A.; Delgado, Inácio

    2001-07-01

    The Brazilian Shield extends over much of South America to the east of the Andean Chain, and is partly covered by Phanerozoic sedimentary rocks. The three major tectonic units (older than 900 Ma) of the shield are the Amazon, São Francisco, and Rio de la Plata Cratons, whereas rocks of the Neoproterozoic (900-550 Ma) Brasiliano Cycle belts surround the cratons in the eastern half of Brazil. Paleoarchean rocks occur as small cratonic nuclei in northeastern Brazil, but the cratons contain voluminous 3.0-2.6-Ga granitic and greenstone belts and a large volume of Paleoproterozoic rocks. Late Mesoproterozoic belts (~1.2 Ga) occur in the western and northwestern Amazon Craton and possibly in northeastern Brazil. There are voluminous Paleoproterozoic and Mesoproterozoic intrusive and volcanic rocks in the Amazon Craton. Belts of reworked crust are common, but the Amazon Craton grew to the north and west mainly during accretionary orogens. The Neoproterozoic Brasiliano Cycle belts contain 5% of juvenile crust in central and southern Brazil, but are dominantly derived from reworking of older crust. It is possible that the cratons were continuous in a super-continent during the Mesoproterozoic prior to the Brasiliano Cycle. Gold deposits are concentrated in the Archean and Paleoproterozoic terranes, including the Carajás and Quadrilátero Ferrífero gold provinces of the Amazon and São Francisco Cratons, respectively, but some also occur in younger terranes. Recent alluvial gold deposits and supergene deposits in the weathering zone are widespread in Brazil.

  5. Post-orogenic subsidence and uplift of the Carpathian belt: An integrated approach

    Science.gov (United States)

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

    2003-04-01

    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

  6. Magnetic reorientation induced by pressure solution: A potential mechanism for orogenic-scale remagnetizations

    Science.gov (United States)

    Oliva-Urcia, Belén; Pueyo, Emilio L.; Larrasoaña, Juan C.

    2008-01-01

    New paleomagnetic analyses of Triassic, Cretaceous and Eocene strata in the south-central Pyrenees show evidence for a widespread remagnetization, located along the southern border of the Axial Zone, the Internal Sierras, and the northern part of the Jaca-Pamplona basin. This remagnetization, always reversed in polarity, was acquired after an extensive period of Late Eocene-Early Oligocene folding and tilting in the area, and affects limestones, sandstones, marls and red beds. In addition, a characteristic prefolding component was identified in 30% of Upper Cretaceous and Triassic red beds. These results, together with a revaluation of previously published paleomagnetic data from the central Pyrenees, indicate that the spatial distribution of the postfolding remagnetization coincides with that of a domain of pressure solution cleavage. A relationship between the intensity of the remagnetization and the characteristic (prefolding component) with respect to the density of cleavage surfaces, leads us to propose a mechanism for the remagnetization related to the development of pressure solution cleavage that is framed within the tectonic evolution of the central Pyrenees. Partial dissolution of rock under tectonic compression leads to the liberation and subsequent accumulation of insoluble minerals in cleavage planes. Magnetic grains are part of the relatively insoluble residue, and they reorient in the presence of the ambient field after they are freed during dissolution of the rock matrix. Chemical reequilibrium (dissolution and/or neoformation of magnetic carriers) during this process cannot be excluded. The remagnetization mechanism we propose can help to explain widespread remagnetizations in low to moderately deformed rocks without the need of large-scale migration of orogenic fluids.

  7. Crustal evolution in the East African Orogen: a neodymium isotopic perspective

    Science.gov (United States)

    Stern, Robert J.

    2002-05-01

    The East African Orogen (EAO) is one of Earth's great collision zones, where East and West Gondwana collided to form the supercontinent `Greater Gondwana' or `Pannotia' at the end of Neoproterozoic time. There is now sufficient Nd isotopic data for basement rocks of the EAO to yield a useful summary. A total of 449 samples were gleaned from the literature, recalculated to a common value for the La Jolla Nd standard, and entered in Excel spreadsheets. This data set was filtered to exclude samples with 147Sm/ 144Nd> 0.165, considered to yield unreliable model ages, leaving 413 suitable data. The crust of the Arabian-Nubian Shield, including Egypt east of the Nile, Sudan east of the Keraf suture, Sinai, Israel, Jordan, most of Arabia, Eritrea, and northern Ethiopia yields overwhelmingly Neoproterozoic model ages. Crust to the east, in the Afif terrane of Arabia, Yemen, Somalia, and Eastern Ethiopia yields much older model ages, averaging 2.1 Ga, demonstrating an abundance of reworked ancient crust. This provides an isotopic link with Madagascar (mean age of 2.4 Ga), which in pre-Jurassic reconstructions lies on the southern extension of this older, remobilized tract. Crust in the far southern extreme of the EAO in Tanzania also yields ancient model ages, averaging 2.3 Ga. The central EAO, in southern Ethiopia and Kenya, yields intermediate ages (mean 1.1-1.2 Ga), interpreted to indicate extensive mixing between Neoproterozoic mantle-derived melts and ancient crust. The Nd isotope data indicate that the northern EAO is composed of juvenile Neoproterozoic crust sandwiched between reworked older crust, whereas the EAO farther south is progressively dominated by ancient crust reworked during Neoproterozoic time. The distribution of juvenile and reworked ancient crust suggests that the most intense collision between East and West Gondwana occurred in the southern part of the EAO.

  8. Fluid-rock interaction and thermochemical evolution of the eastern Alice Springs Orogen, central Australia

    Science.gov (United States)

    Varga, Jan; Hand, Martin; Raimondo, Tom; Kelsey, David

    2017-04-01

    The Harts Range rift and basement complex is located in the eastern Alice Springs Orogen, central Australia. For the period 450-320 Ma, this tectonic domain is characterised by large-scale deformation of the Harts Range Group rift sequence and pervasive reworking of its underlying basement. Fluid-rock interaction is evidenced by extensive pegmatite intrusion and retrogression occurring episodically throughout this 130 Myr period, possibly coeval with prograde upper-amphibolite facies metamorphism. The orthogneiss-dominated Entia Gneiss Complex (EGC) represents basement structurally underlying the Harts Range Group, and has evidence for associated deformation and fluid ingress between 390-320 Ma. The EGC also contains metapelites at various structural levels of the mid- to lower-crust, providing a means to constrain the thermobarometric record during a period of significant rheological weakening. Despite existing studies, the source of fluid that contributed to pervasive deformation and metamorphism is unresolved. Additionally, the role of fluid in the episodic history of crustal melting, and ultimately the generation of large-scale tectonic reworking in the Harts Range Group, remains unclear. In this contribution, we integrate U-Pb monazite geochronology, geochemistry, petrography and phase equilibria forward modelling from various metapelitic rocks at different structural levels of the Entia Gneiss Complex. Preliminary data show that the timing of metamorphism coincides with pegmatite crystallisation ages. These constraints form the basis for understanding the conditions and timing at which fluid flow occurred, and the potential sources of the fluid will be constrained by stable isotope analyses (δ18O and δD). The combination of in situ geochronological data with petrographic observations linked to P - T models is vital in providing temporal constraints on the physical and thermal evolution of the reworking event.

  9. The Italian Submarine Force in the Battle of the Atlantic: Left in the Dark

    Science.gov (United States)

    2014-12-12

    design during the Interwar period. Part of this discussion will focus on German U-boat design and capabilities prior to the Versailles Treaty in...patrols can be attributed to the restrictions imposed by the Treaty of Versailles and the amount of time required to re-build a German submarine force...

  10. Kolumbo submarine volcano (Greece): An active window into the Aegean subduction system.

    Science.gov (United States)

    Rizzo, Andrea Luca; Caracausi, Antonio; Chavagnac, Valèrie; Nomikou, Paraskevi; Polymenakou, Paraskevi N; Mandalakis, Manolis; Kotoulas, Georgios; Magoulas, Antonios; Castillo, Alain; Lampridou, Danai

    2016-06-17

    Submarine volcanism represents ~80% of the volcanic activity on Earth and is an important source of mantle-derived gases. These gases are of basic importance for the comprehension of mantle characteristics in areas where subaerial volcanism is missing or strongly modified by the presence of crustal/atmospheric components. Though, the study of submarine volcanism remains a challenge due to their hazardousness and sea-depth. Here, we report (3)He/(4)He measurements in CO2-dominated gases discharged at 500 m below sea level from the high-temperature (~220 °C) hydrothermal system of the Kolumbo submarine volcano (Greece), located 7 km northeast off Santorini Island in the central part of the Hellenic Volcanic Arc (HVA). We highlight that the mantle below Kolumbo and Santorini has a (3)He/(4)He signature of at least 7.0 Ra (being Ra the (3)He/(4)He ratio of atmospheric He equal to 1.39×10(-6)), 3 Ra units higher than actually known for gases-rocks from Santorini. This ratio is also the highest measured across the HVA and is indicative of the direct degassing of a Mid-Ocean-Ridge-Basalts (MORB)-like mantle through lithospheric faults. We finally highlight that the degassing of high-temperature fluids with a MORB-like (3)He/(4)He ratio corroborates a vigorous outgassing of mantle-derived volatiles with potential hazard at the Kolumbo submarine volcano.

  11. Environmental monitoring of El Hierro Island submarine volcano, by combining low and high resolution satellite imagery

    Science.gov (United States)

    Eugenio, F.; Martin, J.; Marcello, J.; Fraile-Nuez, E.

    2014-06-01

    El Hierro Island, located at the Canary Islands Archipelago in the Atlantic coast of North Africa, has been rocked by thousands of tremors and earthquakes since July 2011. Finally, an underwater volcanic eruption started 300 m below sea level on October 10, 2011. Since then, regular multidisciplinary monitoring has been carried out in order to quantify the environmental impacts caused by the submarine eruption. Thanks to this natural tracer release, multisensorial satellite imagery obtained from MODIS and MERIS sensors have been processed to monitor the volcano activity and to provide information on the concentration of biological, chemical and physical marine parameters. Specifically, low resolution satellite estimations of optimal diffuse attenuation coefficient (Kd) and chlorophyll-a (Chl-a) concentration under these abnormal conditions have been assessed. These remote sensing data have played a fundamental role during field campaigns guiding the oceanographic vessel to the appropriate sampling areas. In addition, to analyze El Hierro submarine volcano area, WorldView-2 high resolution satellite spectral bands were atmospherically and deglinted processed prior to obtain a high-resolution optimal diffuse attenuation coefficient model. This novel algorithm was developed using a matchup data set with MERIS and MODIS data, in situ transmittances measurements and a seawater radiative transfer model. Multisensor and multitemporal imagery processed from satellite remote sensing sensors have demonstrated to be a powerful tool for monitoring the submarine volcanic activities, such as discolored seawater, floating material and volcanic plume, having shown the capabilities to improve the understanding of submarine volcanic processes.

  12. The fate of the submarine ikaite tufa columns in southwest Greenland under changing climate conditions

    DEFF Research Database (Denmark)

    Hansen, Marc O.; Buchardt, Bjørn; Kühl, Michael

    2011-01-01

    carbonate tufa columns. Here, ikaite is formed as a result of submarine spring water mixing with cold seawater. As ikaite disintegrates at temperatures above 6–7uC, it has been speculated that global warming could endanger this unique habitat as well as other sites. In Ikka Fjord in situ water chemistry...

  13. Frontal and Lateral Submarine Lobe Fringes: Comparing Sedimentary Facies, Architecture and Flow Processes

    NARCIS (Netherlands)

    Spychala, Yvonne T.; Hodgson, David M.; Prélat, Amandine; Kane, Ian A.; Flint, Stephen S.; Mountney, Nigel P.

    2017-01-01

    Submarine lobe-fringe deposits form heterolithic successions that may include a high proportion of hybrid beds. The identification of lobe-fringe successions aids interpretation of paleogeographic setting and the degree of basin confinement. Here, for the first time, the sedimentological and

  14. Contributions for the modelling of submarine cables – current density and simplified modelling of wired layers

    DEFF Research Database (Denmark)

    Silva, Filipe Miguel Faria da; Bak, Claus Leth; Ebdrup, Thomas

    2015-01-01

    This article researches two topics relevant for the development of accurate formulae able to estimate the ampacity of HVAC submarine cables. Simplified formulae for estimating the current density distribution, which can be used for theoretical analyses, are developed and compared with the exact...

  15. The Future of the Ballistic Missile Submarine Force in the Russian Nuclear Triad

    Science.gov (United States)

    2008-09-01

    financial setbacks, missile technology failures, and the Kursk sinking in 2000, the SSBN force has slipped back to a lesser prominence.9 B. MAJOR...range category. In the battle for survival, the SLBMs and ALCMs are the most likely potential losers. When the two platforms – submarines and

  16. Scientific Ocean Drilling Behind the Assessment of Geo-Hazards from Submarine Slides

    Directory of Open Access Journals (Sweden)

    Gemma Ercilla

    2007-03-01

    Full Text Available The workshop ‘Scientific Ocean Drilling Behind the Assessment of Geo-hazards from Submarine Slides’ was held on 25–27 October 2006 in Barcelona (Spain. Fifty mainly European scientists and industry representatives attended from a wide spectrum of disciplines such as geophysics, stratigraphy, sedimentology, paleoceanography, marinegeotechnology, geotechnical engineering, and tsunami modeling.

  17. Estimation of submarine mass failure probability from a sequence of deposits with age dates

    Science.gov (United States)

    Geist, Eric L.; Chaytor, Jason D.; Parsons, Thomas E.; ten Brink, Uri S.

    2013-01-01

    The empirical probability of submarine mass failure is quantified from a sequence of dated mass-transport deposits. Several different techniques are described to estimate the parameters for a suite of candidate probability models. The techniques, previously developed for analyzing paleoseismic data, include maximum likelihood and Type II (Bayesian) maximum likelihood methods derived from renewal process theory and Monte Carlo methods. The estimated mean return time from these methods, unlike estimates from a simple arithmetic mean of the center age dates and standard likelihood methods, includes the effects of age-dating uncertainty and of open time intervals before the first and after the last event. The likelihood techniques are evaluated using Akaike’s Information Criterion (AIC) and Akaike’s Bayesian Information Criterion (ABIC) to select the optimal model. The techniques are applied to mass transport deposits recorded in two Integrated Ocean Drilling Program (IODP) drill sites located in the Ursa Basin, northern Gulf of Mexico. Dates of the deposits were constrained by regional bio- and magnetostratigraphy from a previous study. Results of the analysis indicate that submarine mass failures in this location occur primarily according to a Poisson process in which failures are independent and return times follow an exponential distribution. However, some of the model results suggest that submarine mass failures may occur quasiperiodically at one of the sites (U1324). The suite of techniques described in this study provides quantitative probability estimates of submarine mass failure occurrence, for any number of deposits and age uncertainty distributions.

  18. CLAM - CoLlAborative eMbedded networks for submarine surveillance: An overview

    NARCIS (Netherlands)

    Meratnia, Nirvana; Havinga, Paul J.M.; Casari, Paolo; Petrioli, Chiara; Grythe, Knut; Husoy, Thor; Zorzi, Michele

    2011-01-01

    This paper provides an overview of the CLAM project, which aims at developing a collaborative embedded monitoring and control platform for submarine surveillance by combining cutting edge acoustic vector sensor technology and 1D, 2D, 3D sensor arrays, underwater wireless sensor networks protocol

  19. Terrestrial-style slow-moving earthflow kinematics in a submarine landslide complex

    Science.gov (United States)

    Joshu J. Mountjoy; Jim McKean; Philip M. Barnes; Jarg R. Pettinga

    2009-01-01

    Morphometric analysis of Simrad EM300 multibeam bathymetric DEMs reveals details of deformation patterns in a ~145 km2 submarine landslide complex that are commonly associated with slow-moving earthflows in terrestrial settings. This mode of failure, where existing landslide debris is remobilised repeatedly along discrete shear boundaries and is...

  20. Exchange Flow of Oil and Sea-Water in a Ruptured Submarine Pipeline

    NARCIS (Netherlands)

    Kranenburg, C.

    1983-01-01

    The rupture of a submarine oil pipeline starts var10US mechanisms leading to an oil spill. Among these mechanisms the leakage of oil driven by the difference in specific gravities of oil and seawater is difficult to quantify. A simple mathematical model has been developed and laboratory experiments

  1. Buoyancy-driven leakage of oil from a ruptured submarine pipeline

    NARCIS (Netherlands)

    Kranenburg, C.

    1983-01-01

    The rupture of a submarine oil pipeline starts various mechanisms leading to an oil spill. Among these mechanisms the leakage of oil driven by the difference in specific gravities of oil and sea-water is difficult to estimate. A simple mathematical model has been developed and laboratory experiments

  2. Geochemical stratigraphy of submarine lavas (3-5 Ma) from the Flamengos Valley, Santiago, Cape Verde

    DEFF Research Database (Denmark)

    Barker, Abigail K; Holm, Paul Martin; Peate, David W.

    2009-01-01

    New high-precision Pb-Sr-Nd isotope, major and trace element and mineral chemistry data are presented for the submarine stage of ocean island volcanism on Santiago, one of the southern islands of the Cape Verde archipelago. Pillow basalts and hyaloclastites in the Flamengos Valley are divided...

  3. Common Submarine Radio Room: A Case Study of a System of Systems Approach

    Science.gov (United States)

    2014-09-01

    11. Land Attack/Strike Mission Scenario (from PMW770 2011b, 52) .................30 Figure 12. CSG/ ESG Mission Scenario (from PMW770 2011b, 67...request EHF extremely high frequency ESG expeditionary strike group ETR Submarine communications electronics technician FRD Fleet readiness...expeditionary strike group operations mission (CSG/ ESG ) 4. Special operations forces mission (SOF) 5. Mine warfare operations mission (MIW) 6

  4. Mapping submarine sand waves with multiband imaging radar - 2. Experimental results and model comparison

    NARCIS (Netherlands)

    Vogelzang, J.; Wensink, G.J.; Calkoen, C.J.; Kooij, M.W.A. van der

    1997-01-01

    On August 16, 1989, and on July 12, 1991, experiments were performed to study the mapping of submarine sand waves with the airborne imaging radar, a polarimetric (and, in 1991, interferometric) airborne P, L, and C band synthetic aperture radar system. The experiments took place in an area 30 km off

  5. Adaptation of a submarine transient detector to the detection of whale sounds

    NARCIS (Netherlands)

    Hotho, G.H.

    1999-01-01

    As part of an international effort to investigate a potential link between acoustic trials (SWAC 4) of SACLANTCEN with a stranding of Cuvier's beaked whales on the Greek coast in May 1996. TNO-FEL's Transient Detection Demonstrator (TDD). a tool to automatically search for submarine transients in

  6. The Risk of Hydrogen Explosion an a Submarine Part 3 Production of Hydrogen Mixes

    Directory of Open Access Journals (Sweden)

    Kłos Ryszard

    2017-03-01

    Full Text Available This series of articles presents the problems associated with the conduction of a high-risk project aimed at modernising the hydrogen combustion engines on a submarine. The article describes technical issues connected with obtaining hydrogen-air mixes.

  7. Global land-ocean linkage: direct inputs of nitrogen to coastal waters via submarine groundwater discharge

    NARCIS (Netherlands)

    Beusen, A.H.W.; Slomp, C.P.; Bouwman, A.F.

    2013-01-01

    The role of submarine groundwater discharge (SGD), the leakage of groundwater from aquifers into coastal waters, in coastal eutrophication has been demonstrated mostly for the North American and European coastlines, but poorly quantified in other regions. Here, we present the first spatially

  8. Possible climate preconditioning on submarine landslides along a convergent margin, Nankai Trough (NE Pacific)

    Science.gov (United States)

    Kremer, Katrina; Usman, Muhammed O.; Satoguchi, Yasufumi; Nagahashi, Yoshitaka; Vadakkepuliyambatta, Sunil; Panieri, Giuliana; Strasser, Michael

    2017-12-01

    Submarine landslides are major agents of sediment mass transfer from the shallow to deep sea. Due to their rapid emplacement and tsunamigenic potential, such landslides are significant geohazards for society and off- and on-shore infrastructure. The relationship between climate change and the occurrence of submarine landslides is widely debated. However, there is a lack of continuous long-term submarine landslide records with which to comprehensively understand the relationship between climate-driven forces and submarine landslide occurrence. Here, using oxygen isotope stratigraphy in combination with tephrochronology, we date a 1 Myr continuous record of six landslide deposits (at 13.0-14.2, 323-339, 372-384, 394-413, 508-521, and 857-867 ka) recorded in a slope basin of the Nankai Trough subduction zone, off-shore Japan, which represents the major outcome of this study. The ages of the six landslides coincide mostly with interglacial periods. Thus, we propose that climate forcing might act as a preconditioning factor for slope instability in this active tectonic region.[Figure not available: see fulltext.

  9. Near-bottom particulate matter dynamics in the Nazare submarine canyon under calm and stormy conditions

    NARCIS (Netherlands)

    Martín, J.; Palanques, A.; Vitorino, J.; Oliveira, A.; de Stigter, H.C.

    2011-01-01

    Two mooring lines equipped with near-bottom sediment traps were deployed in the axis of the Nazare submarine canyon at similar to 1600 and similar to 3300 m depth, respectively. We studied time-series of particle flux, composition (biogenic silica, carbonates, organic matter and lithogenic

  10. Autonomous long-term gamma-spectrometric monitoring of submarine groundwater discharge trends in Hawaii

    Czech Academy of Sciences Publication Activity Database

    Dulai, H.; Kameník, Jan; Waters, C. A.; Kennedy, J.; Babinec, J.; Jolly, J.; Williamson, M.

    2016-01-01

    Roč. 307, č. 3 (2016), s. 1865-1870 ISSN 0236-5731. [10th International Conference on Methods and Applications of Radioanalytical Chemistry (MARC). Kailua Kona, 12.04.2015-17.04.2015] Institutional support: RVO:61389005 Keywords : submarine groundwater discharge * long-term SGD monitoring * underwater gammaspectrometry Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.282, year: 2016

  11. Probabilistic Hazard of Tsunamis Generated by Submarine Landslides in the Cook Strait Canyon (New Zealand)

    Science.gov (United States)

    Lane, Emily M.; Mountjoy, Joshu J.; Power, William L.; Mueller, Christof

    2016-12-01

    Cook Strait Canyon is a submarine canyon that lies within ten kilometres of Wellington, the capital city of New Zealand. The canyon walls are covered with scars from previous landslides which could have caused local tsunamis. Palaeotsunami evidence also points to past tsunamis in the Wellington region. Furthermore, the canyon's location in Cook Strait means that there is inhabited land in the path of both forward- and backward-propagating waves. Tsunamis induced by these submarine landslides pose hazard to coastal communities and infrastructure but major events are very uncommon and the historical record is not extensive enough to quantify this hazard. The combination of infrequent but potentially very consequential events makes realistic assessment of the hazard challenging. However, information on both magnitude and frequency is very important for land use planning and civil defence purposes. We use a multidisciplinary approach bringing together geological information with modelling to construct a Probabilistic Tsunami Hazard Assessment of submarine landslide-generated tsunami. Although there are many simplifying assumptions used in this assessment, it suggests that the Cook Strait open coast is exposed to considerable hazard due to submarine landslide-generated tsunamis. We emphasise the uncertainties involved and present opportunities for future research.

  12. Beam propagation of tidal internal waves over a submarine slope of the Mascarene Ridge

    Science.gov (United States)

    Morozov, E. G.; Nechvolodov, L. V.; Sabinin, K. D.

    2009-12-01

    The generation of internal tides over the Mascarene Ridge is studied on the basis of moored measurements and numerical modeling. The beam structure of the internal wave propagation over a submarine ridge is analyzed. The dependence of the beam propagation of the perturbations on the steepness of the slope, the depth of the ridge crest, and the stratification is studied.

  13. Noble gas systematics of submarine alkalic lavas near the Hawaiian hotspot

    NARCIS (Netherlands)

    Hanyu, T.; Clague, D.A.; Kaneoka, I.; Dunai, T.J.; Davies, G.R.

    2005-01-01

    Noble gas isotopic ratios were determined for submarine alkalic volcanic rocks distributed around the Hawaiian islands to constrain the origin of such alkalic volcanism and hence understand the details of mantle upwelling beneath Hawaii. Samples were collected by dredging or using submersibles from

  14. Submarine groundwater discharge within a landslide scar at the French Mediterranean coast

    Science.gov (United States)

    Oehler, Till; Mogollón, José M.; Moosdorf, Nils; Winkler, Andreas; Kopf, Achim; Pichler, Thomas

    2017-11-01

    Submarine groundwater discharge (SGD), the flow of fresh and saline groundwater from the seabed into the coastal ocean, has been intensively investigated in the recent years. This research has usually been restricted to shallow water and intertidal areas, whereas knowledge about groundwater seepage in deeper water is mainly limited to point sources from karstic aquifers. In this study we observed submarine groundwater seepage and a subterranean estuary in sediments at water depths of 20-44 m located within the Ligurian Margin, western Mediterranean Sea. Here, a catastrophic submarine landslide occurred near the Nice airport (French Ligurian coast) in the fall of 1979 after a period of heavy rainfall. During two research cruises, gravity cores were recovered in and around the area of the landslide scar. Pore water samples collected from sediment cores indicated sediments containing freshwater within the landslide scar. Pore water profiles of selected ions, such as chloride, ammonium, manganese, sulfate and barium were used to assess transport and reaction processes within the sediment. A 1-dimensional transport model indicates in most cores upward pore water velocities of 2.3-8.8 cm yr-1. This study shows that submarine groundwater seepage along the French Mediterranean coastline can occur at water depths reaching 44 m.

  15. On thrusting, regional unconformities and exhumation of high-grade greenstones in Neoarchean orogens. The case of the Waroonga Shear Zone, Yilgarn Craton

    Science.gov (United States)

    Zibra, I.; Korhonen, F. J.; Peternell, M.; Weinberg, R. F.; Romano, S. S.; Braga, R.; De Paoli, M. C.; Roberts, M.

    2017-08-01

    During the Neoarchean, the dominant tectonic style progressively changed from an episodic-overturn/stagnant-lid regime to modern-style plate tectonics. The Neoarchean strengthening of continental lithosphere changed the style of deformation of orogenic belts. The case study presented here provides insights into how such transition in tectonic style occurred, a matter that is generally controversial. We present structural and metamorphic data from the c. 2660 Ma Waroonga Shear Zone (WSZ) in the Neoarchean Yilgarn orogen (Western Australia). The WSZ contains a syntectonic pluton and older, high-grade greenstones. The tectonic fabric in the pluton developed during melt-present thrusting, followed by syn-cooling wrench-dominated transpression. Mafic greenstones preserve three metamorphic assemblages. The M1 assemblage (Grt-Cpx-Qtz) records peak P-T conditions of 12 ± 1 kbar and 800 ± 50 °C, followed by isothermal decompression to 9 kbar (M2). These anhydrous assemblages might predate the WSZ. Greenstones then underwent decompression at c. 2660 Ma (3-4 kbar; 600-650 °C), defined by the amphibole-rich M3 assemblage, synkinematic with the tectonic fabric in the WSZ. We show that shearing along the WSZ exhumed these greenstones by at least 10 km, inducing major uplift and erosion. Archean accretionary orogens developed on weak lithosphere, where deformation suppressed crustal thickening, orogenic relief and synorogenic exhumation of orogenic roots. However, our study indicates a genetic link between (i) strain localization along contractional structures, inducing large-scale uplift; (ii) exhumation of high-grade greenstones; (iii) development of inverse metamorphic gradients; (iv) establishment of a regional unconformity, with clastic sediments fed by the uplifted terrane; (v) incorporation of portions of the newly-formed orogenic basins into the footwall of the WSZ. These features imply that the Yilgarn orogenic lithosphere at c. 2660 Ma was stiff enough to allow

  16. From the plutonic root to the volcanic roof of a continental magmatic arc: a review of the Neoproterozoic Araçuaí orogen, southeastern Brazil

    Science.gov (United States)

    Gonçalves, Leonardo; Alkmim, Fernando F.; Pedrosa-Soares, Antônio; Gonçalves, Cristiane C.; Vieira, Valter

    2018-01-01

    The Araçuaí-West Congo orogen (AWCO) is one of the various components of the Brasiliano/Pan-African orogenic network generated during the amalgamation of West Gondwana. In the reconstructions of Gondwana, the AWCO, encompassing the Araçuaí orogen of South America and the West Congo belt of Southwestern Africa, appears as a tongue-shaped orogenic zone embraced by the São Francisco-Congo craton. Differing from the vast majority of the known orogens owing to its singular confined setting, the AWCO contains a large amount of orogenic igneous rocks emplaced in all stages of its tectonic evolution. We present new and revised information about the oldest Ediacaran granitic assemblage, the G1 Supersuite, which together with the Rio Doce Group defines the Rio Doce magmatic arc, and then we propose a new tectonic setting for the arc. Field relationships and mineralogical compositions of the G1 Supersuite allow us to characterize three lithofacies associations, Opx-bearing rocks, enclave-rich Tonalite-Granodiorite and enclave-poor Granite-Tonalite, suggesting different crustal levels are exposed in the central part of the Araçuaí orogen. The region is interpreted to represent a tilted crustal section, with deep arc roots now exposed along its western border. Chemically, these plutonic associations consist mostly of magnesian, metaluminous to slightly peraluminous, calc-alkaline to alkali-calcic and medium- to high-K acidic rocks. The dacitic and rhyolitic rocks of the Rio Doce Group are mainly magnesian, peraluminous, calcic to calc-alkaline, and medium- to high-K acidic rocks. Zircon U-Pb data constrain the crystallization of the granitoids between ca. 625 and 574 Ma, while the age of the metamorphosed volcanic rocks is around ca. 585 Ma. Thus, within errors, these rock associations likely belong to the same magmatic event and might represent the subduction-related, pre-collisional, evolution of the Araçuaí orogen. In addition, whole-rock Sm-Nd isotopic compositions

  17. A Taiwan Study Abroad Program on Aging, Culture, and Healthcare

    Science.gov (United States)

    Hou, Su-I

    2018-01-01

    This article introduces a Taiwan Study Abroad program on aging, culture, and healthcare. The program is a short-term academic summer program (6 credits) to bring U.S. students to Taiwan. During 2011 ~ 2015, a total of four groups including over 54 students and faculty members participated. This program partnered with multiple universities,…

  18. GIS Adoption among Senior High School Geography Teachers in Taiwan

    Science.gov (United States)

    Lay, Jinn-Guey; Chen, Yu-Wen; Chi, Yu-Lin

    2013-01-01

    This article explores the adoption of geographic information system (GIS) knowledge and skills through in-service training for high school geography teachers in Taiwan. Through statistical analysis of primary data collected from a census of Taiwan's high school geography teachers, it explores what motivates these teachers to undertake GIS…

  19. Counseling Psychology Licensure in Taiwan: Development, Challenges, and Opportunities

    Science.gov (United States)

    Wang, Li-fei; Kwan, Kwong-Liem K.; Huang, Su-Fei

    2011-01-01

    The development and consequences of licensure for counseling psychologists in Taiwan are presented to promote cross-cultural awareness surrounding issues in the counseling psychology profession. The national licensure statute for counseling psychologists in Taiwan was established by the Taiwanese Legislature in 2001. While the licensing system…

  20. Higher Education Research Community in Taiwan: An Emerging Field

    Science.gov (United States)

    Chan, Sheng-Ju; Chan, Ying

    2015-01-01

    This paper aims to explore the evolution and characteristics of the higher education research community in Taiwan. In echoing the development of the East Asian region, Taiwan has made substantial progress during the past two decades. The massification of higher education itself has played a major role in promoting the academic differentiation or…

  1. Kindergarten Teachers' Experience with Reporting Child Abuse in Taiwan

    Science.gov (United States)

    Feng, Jui-Ying; Huang, Tzu-Yi; Wang, Chi-Jen

    2010-01-01

    Objective: The objectives were to examine factors associated with reporting child abuse among kindergarten teachers in Taiwan based on the Theory of Planned Behavior (TPB). Method: A stratified quota sampling technique was used to randomly select kindergarten teachers in Taiwan. The Child Abuse Intention Report Scale, which includes demographics,…

  2. Taiwan Teacher Preparation Program Evaluation: Some Critical Perspectives

    Science.gov (United States)

    Liu, Tze-Chang

    2015-01-01

    This paper focuses on the influences and changes of recent Taiwan teacher preparation program evaluation (TTPPE) as one of the national evaluation projects conducted by the Higher Education Evaluation and Accreditation Council of Taiwan. The main concerns are what kind of ideology is transformed through the policy by means of evaluation, and what…

  3. TAIWAN: The little dragon of the China Sea

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-01

    A review of the political and economic factors affecting the energy policy of Taiwan is presented in the article. The focus is primarily on nuclear power. Installed electric capacity, power generation, and forecasted energy supply is tabulated for primary energy sources. Major features of the six commercial nuclear power plants in Taiwan are listed.

  4. Sedum sarmentosum Bunge (Crassulaceae, a Newly Naturalized Herb in Taiwan

    Directory of Open Access Journals (Sweden)

    Mong-Huai Su

    2014-03-01

    Full Text Available Sedum sarmentosum Bunge (Crassulaceae, a newly naturalized fleshy herb in Taiwan, is reported here. The taxonomic description, line drawing, and photographs are provided. The population is colonized on Mt. Tatun, Yangmingshan National Park, north Taiwan. Since this species was reported being invasive, its impacts on the local ecosystem should be concerned.

  5. Teaching Benchmark Strategy for Fifth-Graders in Taiwan

    Science.gov (United States)

    Yang, Der-Ching; Lai, M. L.

    2013-01-01

    The key purpose of this study was how we taught the use of benchmark strategy when comparing fraction for fifth-graders in Taiwan. 26 fifth graders from a public elementary in south Taiwan were selected to join this study. Results of this case study showed that students had a much progress on the use of benchmark strategy when comparing fraction…

  6. Transformation and Framework of Teacher Professional Development in Taiwan

    Science.gov (United States)

    Huang, Bo-Ruey

    2016-01-01

    This article describes the situation of teacher professional development in Taiwan, including the history and the framework of teacher professional development. With diversification of teacher education systems and institutions, teacher professional development in Taiwan is undergoing a gradual governance shift from the model of centralised state…

  7. The United States, China and Taiwan: Reunification, Reconciliation or War?

    National Research Council Canada - National Science Library

    Fogarty, Stephen

    2003-01-01

    ....), the Peoples Republic of China (PRO) and Taiwan from 1949 until 2020. The primary question this project will attempt to answer is whether the three countries will be able to achieve a peaceful resolution to ongoing tensions over the Taiwan Straits...

  8. Parents' Attitudes toward the English Education Policy in Taiwan

    Science.gov (United States)

    Chang, Yuh Fang

    2008-01-01

    Taiwan, like many other countries in Asia, introduced considerable changes in English education policy in response to the need for English communication in the global market. During the process of implementing the new English education policy, the Ministry of Education (MOE) of Taiwan encountered several problems. Although researchers have…

  9. A Re-Examination of the Suicide Rates in Taiwan

    Science.gov (United States)

    Chuang, Hwei-Lin; Huang, Wei-Chiao

    2007-01-01

    This paper examines the suicide rates of 23 cities and counties in Taiwan from 1983 to 2001. We found that a combination of economic and social variables can significantly account for the tremendous variations in suicide rates across Taiwan's cities and counties over the last two decades. The level of income per capita in a region appears as the…

  10. Intercultural Training for US Business Expatriates in Taiwan

    Science.gov (United States)

    Chien, Tien-Chen; McLean, Gary N.

    2011-01-01

    Purpose: This study aims to explore the intercultural training needs for US business expatriates on assignment in Taiwan. The study assesses Taiwan culture-specific training needs of US expatriates from the perspectives of both US expatriates and their Taiwanese colleagues and compares the perceived importance of these intercultural training needs…

  11. US Navy Submarine Sea Trial of the NASA Air Quality Monitor

    Science.gov (United States)

    Limero, Thomas; Wallace, William T.; Manney, Joshua A.; Mudgett, Paul D.

    2017-01-01

    For the past four years, the Air Quality Monitor (AQM) has been the operational instrument for measuring trace volatile organic compounds on the International Space Station (ISS). The key components of the AQM are the inlet preconcentrator, the gas chromatograph (GC), and the differential mobility spectrometer. Most importantly, the AQM operates at atmospheric pressure and uses air as the GC carrier gas, which translates into a small reliable instrument. Onboard ISS there are two AQMs, with different GC columns that detect and quantify 22 compounds. The AQM data contributes valuable information to the assessment of air quality aboard ISS for each crew increment. The U.S. Navy is looking to update its submarine air monitoring suite of instruments, and the success of the AQM on ISS has led to a jointly planned submarine sea trial of a NASA AQM. In addition to the AQM, the Navy is also interested in the Multi-Gas Monitor (MGM), which was successfully flown on ISS as a technology demonstration to measure major constituent gases (oxygen, carbon dioxide, water vapor, and ammonia). A separate paper will present the MGM sea trial results. A prototype AQM, which is virtually identical to the operational AQM, has been readied for the sea trial. Only one AQM will be deployed during the sea trial, but it is sufficient to detect the compounds of interest to the Navy for the purposes of this trial. A significant benefit of the AQM is that runs can be scripted for pre-determined intervals and no crew intervention is required. The data from the sea trial will be compared to archival samples collected prior to and during the trial period. This paper will give a brief overview of the AQM technology and protocols for the submarine trial. After a quick review of the AQM preparation, the main focus of the paper will be on the results of the submarine trial. Of particular interest will be the comparison of the contaminants found in the ISS and submarine atmospheres, as both represent

  12. Rapid Submarine Melting Driven by Subglacial Discharge, LeConte Glacier, Alaska

    Science.gov (United States)

    Motyka, R. J.; Dryer, W. P.; Amundson, J. M.; Truffer, M.; Fahnestock, M. A.

    2013-12-01

    Submarine melting impacts the stability of tidewater glaciers worldwide, but the connections between the ocean, a warming climate, and retreat of outlet glaciers are poorly known. Clearly warm seawater plays an important role, but the tremendous heat potential resident in oceans and fjords must first be brought into contact with outlet glacier termini in order to affect them. We show here that for many glaciers, the principal process driving high rates of submarine melting is subglacial discharge of freshwater. This buoyant discharge draws in warm seawater, entraining it in a turbulent upwelling convective flow along the submarine face that melts glacier ice. To capture the effect of changing subglacial discharge on submarine melting, we conducted four days of hydrographic transects during late summer 2012 at LeConte Glacier, Alaska. A major rainstorm allowed us to directly measure the influence of large changes in subglacial discharge. We found strong submarine melt rates that increased from 9.0×1.0 to 16.8×1.3 m/d (ice face equivalent frontal ablation) as subglacial discharge increased from 130 to 440 m^3/s over a four day period. This subglacial discharge drove influx of warm seawater (thermal forcing ~ 8° C) to the terminus with fluxes increasing from 1800 to 4000 m3/s. Our ice equivalent frontal ablation rates due to submarine melting are two to three times values found for Greenland glaciers, where thermal forcing is substantially lower (~ 1 - 4 °C) and termini are wider. Together, these studies confirm the importance of submarine melting at grounded glaciers. At LeConte, the total frontal ablation rate (calving flux plus submarine melting) is ~ 3.0 x10^6 m^3/d w.e., which far surpasses surface ablation. One-half to two-thirds of the frontal ablation during September 2012 can be attributed to submarine melting. A two-layer model driven by a buoyant plume of subglacial discharge has been previously invoked to describe the proglacial fjord circulation

  13. A submarine landslide source for the devastating 1964 Chenega tsunami, southern Alaska

    Science.gov (United States)

    Brothers, Daniel; Haeussler, Peter J.; Lee Liberty,; David Finlayson,; Geist, Eric L.; Labay, Keith A.; Michael Byerly,

    2016-01-01

    During the 1964 Great Alaska earthquake (Mw 9.2), several fjords, straits, and bays throughout southern Alaska experienced significant tsunami runup of localized, but unexplained origin. Dangerous Passage is a glacimarine fjord in western Prince William Sound, which experienced a tsunami that devastated the village of Chenega where 23 of 75 inhabitants were lost – the highest relative loss of any community during the earthquake. Previous studies suggested the source of the devastating tsunami was either from a local submarine landslide of unknown origin or from coseismic tectonic displacement. Here we present new observations from high-resolution multibeam bathymetry and seismic reflection surveys conducted in the waters adjacent to the village of Chenega. The seabed morphology and substrate architecture reveal a large submarine landslide complex in water depths of 120–360 m. Analysis of bathymetric change between 1957 and 2014 indicates the upper 20–50 m (∼0.7 km3) of glacimarine sediment was destabilized and evacuated from the steep face of a submerged moraine and an adjacent ∼21 km2 perched sedimentary basin. Once mobilized, landslide debris poured over the steep, 130 m-high face of a deeper moraine and then blanketed the terminal basin (∼465 m water depth) in 11 ± 5 m of sediment. These results, combined with inverse tsunami travel-time modeling, suggest that earthquake- triggered submarine landslides generated the tsunami that struck the village of Chenega roughly 4 min after shaking began. Unlike other tsunamigenic landslides observed in and around Prince William Sound in 1964, the failures in Dangerous Passage are not linked to an active submarine delta. The requisite environmental conditions needed to generate large submarine landslides in glacimarine fjords around the world may be more common than previously thought. 

  14. Boulder emplacement and remobilisation by cyclone and submarine landslide tsunami waves near Suva City, Fiji

    Science.gov (United States)

    Lau, A. Y. Annie; Terry, James P.; Ziegler, Alan; Pratap, Arti; Harris, Daniel

    2018-02-01

    The characteristics of a reef-top boulder field created by a local submarine landslide tsunami are presented for the first time. Our examination of large reef-derived boulders deposited by the 1953 tsunami near Suva City, Fiji, revealed that shorter-than-normal-period tsunami waves generated by submarine landslides can create a boulder field resembling a storm boulder field due to relatively short boulder transport distances. The boulder-inferred 1953 tsunami flow velocity is estimated at over 9 m s- 1 at the reef edge. Subsequent events, for example Cyclone Kina (1993), appear to have remobilised some large boulders. While prior research has demonstrated headward retreat of Suva Canyon in response to the repeated occurrence of earthquakes over the past few millennia, our results highlight the lingering vulnerability of the Fijian coastlines to high-energy waves generated both in the presence (tsunami) and absence (storm) of submarine failures and/or earthquakes. To explain the age discrepancies of U-Th dated coral comprising the deposited boulders, we introduce a conceptual model showing the role of repeated episodes of tsunamigenic submarine landslides in removing reef front sections through collapse. Subsequent high-energy wave events transport boulders from exposed older sections of the reef front onto the reef where they are deposited as 'new' boulders, alongside freshly detached sections of the living reef. In similar situations where anachronistic deposits complicate the deposition signal, age-dating of the coral boulders should not be used as a proxy for determining the timing of the submarine landslides or the tsunamis that generated them.

  15. Petrogenesis of Triassic granitoids in the East Kunlun Orogenic Belt, northern Tibetan Plateau and their tectonic implications

    Science.gov (United States)

    Shao, Fengli; Niu, Yaoling; Liu, Yi; Chen, Shuo; Kong, Juanjuan; Duan, Meng

    2017-06-01

    The East Kunlun Orogenic Belt (EKOB), an important part of the Greater Tibetan Plateau, is an ideal region for understanding the tectonic evolution of the Anyemaqen Ocean. Here, we present zircon U-Pb ages, bulk-rock major and trace element analyses and Sr-Nd-Hf isotope compositions on representative samples of the syn-collisional Dulan batholith at the eastern end of the EKOB. The zircon U-Pb age data indicate that the bulk of the Dulan batholith was emplaced at 240-235 Ma. The granitoids have high- to medium-K and metaluminous characteristics. They are enriched in large ion lithophile elements (LILEs) and light rare earth elements (LREEs) and depleted in some high field strength elements (HFSEs, e.g., Nb and Ta), while having a flat heavy REE (HREEs) pattern. The mafic magmatic enclaves (MMEs) share the same age, mineralogy and indistinguishable Sr-Nd-Hf isotopes with their granitoid hosts except for the higher HREE abundances. We show that the MMEs represent cumulate formed at earlier stages of the same magmatic system. The trace element data (e.g., Nb/Th, Ta/U) and inherited mantle isotopic characteristics of the Dulan batholith are also consistent with an origin via partial melting of the last fragments of underthrusting ocean crust. Simple mass balance calculations using the Sr-Nd-Hf isotopic data show that 85% Paleo-Tethys MORB and 15% mature crustal material (the Proterozoic gneiss of the study area) contribute to the source of the granitoids. The Dulan batholith shows compositional similarities to the bulk continental curst with inherited mantle isotopic signatures. The syn-collisional felsic magmatism must have contributed to the net continental crust growth in the EKOB. We infer that the Kunlun and Qinling orogens may actually be one single orogen offset later by the Wenquan fault system.

  16. COPD in Taiwan: a National Epidemiology Survey

    Directory of Open Access Journals (Sweden)

    Cheng SL

    2015-11-01

    Full Text Available Shih-Lung Cheng,1,2 Ming-Cheng Chan,3 Chin-Chou Wang,4 Ching-Hsiung Lin,5 Hao-Chien Wang,6 Jeng-Yuan Hsu,3 Liang-Wen Hang,7,8 Chee-Jen Chang,9 Diahn-Warng Perng,10,* Chong-Jen Yu6,* On behalf of the Taiwan COPD Consortium 1Department of Internal Medicine, Far Eastern Memorial Hospital, New Taipei City, 2Department of Chemical Engineering and Materials Science, Yuan Ze University, Chung-Li City, Taoyuan County, 3Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, 4Division of Pulmonary and Critical Care Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, 5Division of Chest Medicine, Changhua Christian Hospital, Changhua City, Changhua County, 6Department of Internal Medicine, National Taiwan University Hospital, Taipei, 7Department of Pulmonary and Critical Care Medicine, Sleep Medicine Center, China Medical University Hospital, 8Department of Respiratory Therapy, College of Health Care, China Medical University, Taichung, 9Biostatistical Center for Clinical Research, Chang Gung Memorial Hospital, Linkou Branch, Guishan Township, Taoyuan County, 10Department of Chest Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, Republic of China *These authors contributed equally to this work Objectives: To determine the prevalence of COPD in Taiwan and to document the disease characteristics and associated risk factors.Methods: We conducted a random cross-sectional national survey of adults older than 40 years in Taiwan. Respiratory health screening questions identified subjects with diagnosed COPD or whose reported symptoms also fulfilled an epidemiological case definition; these were eligible to complete the survey, which also included indices of symptom severity and disability and questions on comorbidities, medical treatments, smoking habits, and occupations potentially harmful to respiratory health. Subjects with diagnosed COPD were subdivided by smoking status. Subjects who fulfilled the case definition

  17. Short episodes of crust generation during protracted accretionary processes: Evidence from Central Asian Orogenic Belt, NW China

    Science.gov (United States)

    Tang, Gong-Jian; Chung, Sun-Lin; Hawkesworth, Chris J.; Cawood, P. A.; Wang, Qiang; Wyman, Derek A.; Xu, Yi-Gang; Zhao, Zhen-Hua

    2017-04-01

    Accretionary orogens are major sites of generation of continental crust but the spatial and temporal distribution of crust generation within individual orogens remains poorly constrained. Paleozoic (∼540-270 Ma) granitic rocks from the Alati, Junggar and Chinese Tianshan segments of the Central Asian Orogenic Belt (CAOB) have markedly bimodal age frequency distributions with peaks of ages at ∼400 Ma and 280 Ma for the Altai segment, and ∼430 Ma and 300 Ma for the Junggar and Chinese Tianshan segments. Most of the magma was generated in short time intervals (∼20-40 Ma), and variations in magma volumes and in Nd-Hf isotope ratios are taken to reflect variable rates of new crust generation within a long-lived convergent plate setting. The Junggar segment is characterized by high and uniform Nd-Hf isotope ratios (εNd (t) = + 5 to + 8; zircon εHf (t) = + 10 to + 16) and it appears to have formed in an intra-oceanic arc system. In the Altai and Chinese Tianshan segments, the Nd-Hf isotope ratios (εNd (t) = - 7 to + 8; zircon εHf (t) = - 16 to + 16) are lower, although they increase with decreasing age of the rock units. The introduction of a juvenile component into the Chinese Tianshan and Altai granitic rocks appears to have occurred in continental arc settings and it reflects a progressive reduction in the contributions from old continental lower crust and lithospheric mantle. Within the long-lived convergent margin setting (over ∼200 Ma), higher volumes of magma, and greater contributions of juvenile material, were typically emplaced over short time intervals of ∼20-40 Ma. These intervals were associated with higher Nb/La ratios, coupled with lower La/Yb ratios, in both the mafic and granitic rocks, and these episodes of increased magmatism from intraplate-like sources are therefore thought to have been in response to lithospheric extension. The trace element and Nd-Hf isotope data, in combination with estimates of granitic magma volumes, highlight

  18. Geochemistry, 40Ar/39Ar geochronology, and geodynamic implications of Early Cretaceous basalts from the western Qinling orogenic belt, China

    Science.gov (United States)

    Zhang, Feifei; Wang, Yuejun; Cawood, Peter A.; Dong, Yunpeng

    2018-01-01

    The Qinling-Dabie orogenic belt was formed by the collision of the North and South China Cratons during the Early Mesozoic and subsequently developed into an intracontinental tectonic process during late Mesozoic. Field investigations identified the presence of late Mesozoic basalts in the Duofutun and Hongqiang areas in the western Qinling orogenic belt. The petrogenesis of these basalts provides an important constraint on the late Mesozoic geodynamics of the orogen. The representative basaltic samples yield the 40Ar/39Ar plateau age of about 112 Ma. These samples belong to the alkaline series and have SiO2 ranging from 44.98 wt.% to 48.19 wt.%, Na2O + K2O from 3.44 wt% to 5.44 wt%, and MgO from 7.25 wt.% to 12.19 wt.%. They demonstrate the right-sloping chondrite-normalized REE patterns with negligible Eu anomalies (1.00-1.10) and PM-normalized patterns enriched in light rare earth element, large ion lithophile element and high field strength element, similar to those of OIB rocks. These samples additionally show an OIB-like Sr-Nd isotopic signature with εNd(t) values ranging from +6.13 to +10.15 and initial 87Sr/86Sr ratios from 0.7028 to 0.7039, respectively. These samples are geochemically subdivided into two groups. Group 1 is characterized by low Al2O3 and high TiO2 and P2O5 contents, as well as high La/Yb ratios (>20), being the product of the high-pressure garnet fractionation from the OIB-derived magma. Group 2 shows higher Al2O3 but lower P2O5 contents and La/Yb ratios (<20) than Group 1, originating from asthenospheric mantle with input of delaminated lithospheric component. In combination with available data, it is proposed for the petrogenetic model of the Early Cretaceous thickened lithospheric delamination in response to the asthenospheric upwelling along the western Qinling orogenic belt.

  19. Diapiric activities and intraslope basin development offshore of SW Taiwan: A case study of the Lower Fangliao Basin gas hydrate prospect

    Science.gov (United States)

    Hsu, Ho-Han; Liu, Char-Shine; Chang, Ya-Ting; Chang, Jih-Hsin; Ko, Chia-Chun; Chiu, Shye-Donq; Chen, Song-Chuen

    2017-11-01

    The architecture and distribution of mud diapirs are shaped by tectonic activity, sediment filling and unbalanced loading characteristics. Mud diapir development also controls spatial variations of intraslope basins in slope areas and can spur upward fluid migration with diapiric intrusion. The offshore area of southwestern Taiwan is an incipient collision zone in which thick sequences of deep marine sediments filled a rapidly subsided foredeep basin during the Pliocene. Large volumes of deposited sediment serve as source materials of diapiric ridges that extend NNE-SSW, and some mud diapirs even extend to on land SW Taiwan with subsurface signatures of gas. This study examines relationships between mud diapir and intraslope basin development in convergent tectonics through seismic and bathymetry data analyses. Four types of mud diapirs are identified: (1) buried symmetrical diapirs; (2) symmetrical diapirs extruded above the seafloor; (3) asymmetric and irregular diapirs; and (4) small individual diapirs manifested as mud intrusions found in local areas. A 3-stage model is proposed as a tool for describing the development and distribution of these types of diapirs. We further examine the relationship between mud diapirs and intraslope basin development patterns by analyzing 2D and 3D seismic images to reveal structural and sedimentary processes occurring in the Lower Fangliao Basin. This basin is characterized by BSR and amplitude anomalies of seismic profiles and is a prospect of the Taiwanese gas hydrate investigation project. An 8-stage development model with six depositional units is proposed as a means to explain the evolution of diapirs, submarine canyons, and fold and fault activities in the Lower Fangliao Basin, in turn revealing the relationship between mud diapir formation and intraslope basin development offshore of southwestern Taiwan.

  20. Epidemiology of Enterovirus 71 Infections in Taiwan

    Directory of Open Access Journals (Sweden)

    Min-Yuan Chia

    2014-08-01

    Full Text Available Enterovirus 71 (EV71 was first described in USA in 1969 but retrospective studies in The Netherlands further detected EV71 in the clinical specimens collected in 1963. EV71 has one single serotype measured by using hyperimmune animal antisera but can be phylogenetically classified into three genogroups (A, B, and C including 11 genotypes (A, B1–B5, C1–C5. In Taiwan, EV71 caused a large-scale nationwide epidemic in 1998. Retrospective studies further detected EV71 in clinical specimens collected from hand–foot–mouth disease patients in 1980 and 1986. Therefore, EV71 may have circulated in Taiwan prior to 1980. Since 1998, EV71 has cyclically caused nationwide epidemics with different predominant genotypes in 1998 (genotype C2, 2000–2001 (B4, 2005 (C4, 2008 (B5, and 2012 (B5. Phylogenetic analysis revealed that C4 viruses isolated in 2005 were probably from China, B5 viruses isolated in 2008 were probably from South Eastern Asia, and B5 viruses isolated in 2012 were probably from Xiamen, China. Several studies have collected postinfection sera from children to measure cross-reactive neutralizing antibody titers against different EV71 genotypes and found that antigenic differences between genogroup B and C viruses did not have a clear pattern but that genotype A virus was antigenically different from genogroup B and C viruses. In conclusion, EV71 cyclically caused nationwide epidemics through international importations. EV71 surveillance in Taiwan should combine genetic and serological methods.

  1. Regulatory System of Radiation Protection in Taiwan

    Energy Technology Data Exchange (ETDEWEB)

    Tang, F. T.; Huang, C. C.

    2004-07-01

    After the radioactive contaminated buildings incident occurred in Taiwan in 1993, the competent authority for radiation protection the Atomic Energy Council (AEC) started to review the structured problem of radiation protection regulatory system. Through several years' investigation and study, the AEC has improved two important tools in radiation protection regulatory system, i.e., control regulations and actual practice, and made them more rigorous and efficient. This paper will make a brief introduction of the efforts that Taiwan has made in this respect. Taiwan's radiation protection control was based on the Atomic Energy Law promulgated in 1968, but the control idea and authorization scope were not sufficient to appropriately respond to the highly developed economy and democracy in Taiwan. After several years' legislative process, the Ionizing Radiation Protection Law (IRP Law) was promulgated and entered into force on February 1, 2003. This IRP Law specifically emphasizes categorized risk management of radiation sources, establishment of personnel licenses and training system, enhancement of public safety control, and implementation of quality assurance program for medical exposure. The Legislative Yuan (Congress) fully authorized the competent authority to establish various technological control regulations according to control necessity without prior review by the Legislative Yuan in advance. As to the penalties of the violations of the IRP Law, the AEC adopts high-rated administrative fines and applies the Criminal Law to those who seriously contaminate the environment. In actual practice, the AEC has constructed a Radiation Protection Control Information System compatible with the IRP Law that fully combines the functions of computers and Internet. The information of facility operators who own radiation sources, radiation protection specialists, and operating personnel are entered into this system, starting from the submission of application

  2. Governance and Economic Transformation in Taiwan

    DEFF Research Database (Denmark)

    Lauridsen, Laurids Sandager

    2014-01-01

    This article analyses the strengths and weaknesses of the developmental-state approach as compared with a broader and more flexible developmental-governance approach – in relation to economic transformation in a single case country, Taiwan. It argues that both approaches have strong and weak points......, and comes down in favour of the view that it is only through a ‘thick’ study of political forces, processes and circumstances that the reasoning behind developmental policies and institutions can be understood and the processes of economic transformation explained....

  3. Apparent resistivity and spectral induced polarization in the submarine environment

    Directory of Open Access Journals (Sweden)

    HERCULES DE SOUZA

    2001-09-01

    Full Text Available Relatively few investigations have employed electrical methods in the submarine environment, which may be promising for mineral deposits or threatened by environmental problems. We have measured the electric field using both disk and bar electrodes in the sea water at three different levels: sea surface, seven meters deep, and sea bottom at a depth of ten meters, employing a 2 m spacing dipole-dipole array with 7 array spacings of investigation, and 13 values of frequencies at steps of (2N hertz, N = -2, -1, 0, 1, 2,.....10. The measurement allowed the analysis of the electric field as a function of frequency and spacing, and of the spectral induced polarization. Modelling and interpretation of the apparent resistivity yielded a good fit with previous drilling data. Analysis of the spectrum of the complex apparent resistivity and the comparison with equivalent circuits, provided information about the grain size, the mineral composition and the major induced polarization phenomenon occurring below the sea. Therefore the result of the present research show the feasibility of measuring the variation of seawater resistivity in situ, as well as the resistivity of sea bottom sediments.Relativamente poucas investigações têm empregado métodos elétricos no ambiente submarino, o qual pode ser promissor para depósitos minerais ou ameaçado por problemas ambientais. Nós medimos o campo elétrico usando eletrodos em forma de disco e de barra na água do mar, em três níveis distintos: superfície, sete metros de profundidade, e fundo do mar a dez metros de profundidade, empregando um dispositivo dipolo-dipolo com 2m de afastamento, 7 níveis de investigação e 13 valores de freqüência a intervalos de (2N hertz, N = -2, -1, 0, 1, 2, ... 10. A medida permitiu a análise do campo elétrico como uma função de freqüência e afastamento, e da polarização induzida espectral. A modelagem e a interpretação da resistividade aparente se ajustaram bem

  4. [An outline medical history of Taiwan (I): the period of folklore medicine and witch doctor].

    Science.gov (United States)

    Li, C

    1997-01-01

    The paper makes a correlated analysis on the origin of health folklore between Chinese in mainland and Taiwan island. After quoting literatures written by authors living in the Qing dynasty in Taiwan, this paper analyses health condition among aboriginals of Taiwan during the witchcraft age. Along with the increasing immigration from China mainland to Taiwan island, health of folklore and gods from China mainland were introduced into Taiwan, hence the period of witch doctor in Taiwan, featuring the correlation of both. Though modern medicine in Taiwan is so advanced, yet there are still witch doctors elsewhere.

  5. The Geothermal Potential, Current and Opportunity in Taiwan

    Science.gov (United States)

    Song, Sheng-Rong

    2016-04-01

    Located in the west Pacific Rim of Fire, Taiwan possesses rich geothermal resources due to volcanic activities and rapid uplifting of plate collision. Based on available data prior to 1980, Taiwan may have about 1 GWe of potential shallow geothermal energy, which is less than 3% of the national gross power generation. A 3-Mw pilot power plant, therefore, was constructed in 1981 and terminated in 1993 in the Chingshui geothermal field of Ilan, northeastern Taiwan. Recently, one of the National Science & Technology Program (NSTP) projects has been conducting research and reevaluating the island-wide deep geothermal energy. Four hot potential sites have been recognized. They are: (1) Tatun Volcano Group of northern Taiwan; (2) I-Lan Plain of NE Taiwan; (3) Lu-Shan area of Central Taiwan; and (4) Hua-Tung area of eastern Taiwan. We found that the geothermal resource in Taiwan may be as high as 160 GWe, with 33.6 GWe of exploitable geothermal energy. There are no any commercial geothermal power plants until now in Taiwan, although the potential is great. However, geothermal energy has been listed as one of major tasks of National Energy Program, Phase II (NEP-II) in Taiwan. We will conduct more detailed geothermal energy surveys on some proposed hot sites and to construct an EGS pilot geothermal plant with 1 MWe capability in a few years. Currently, there are three nuclear power plants, named No. 1, 2 & 3, in operations, which produce 16.5% gross generation of electricity and one (No. 4) is under construction, but is stopped and sealed now in Taiwan. Furthermore, the life-span of 40-year operation for those three power plants will be close-at hand and retire in 2018-2019, 2021-2023 and 2024-2025, respectively. Therefore, to find alternative energy sources, especially on the clean, renewable and sustainable ones for generating electricity are emergent and important for Taiwan's government in next few years. Among various energy sources, geothermal energy can be as base

  6. Peering into the deep: Illuminating the crustal evolution of the Eucla basement and its relationship to the Albany-Fraser Orogen of southwest Australia.

    Science.gov (United States)

    Hartnady, Michael; Kirkland, Chris; Clark, Chris; Spaggiari, Catherine; Smithies, Hugh

    2017-04-01

    The Albany-Fraser Orogen is a 1200 km long east to northeasterly trending Palaeoproterozoic to Mesoproterozoic orogenic belt that defines the southern to southeastern margin of the West Australian Craton (WAC). The belt records a long and complex geological history spanning the break-up of Nuna between 2000 and 1700 Ma and amalgamation of Rodinia between 1300 and 1000 Ma. Recent geochronological, geochemical and isotopic work has shown that the Albany-Fraser Orogen formed through a protracted period of reworking of the margin of the Archean Yilgarn Craton (part of the WAC) with various additions of mantle-derived material. The Cretaceous Bight and Cenozoic Eucla Basins partially overlie the northeastern part of the Albany-Fraser Orogen and completely cover 1000 km of crystalline basement (the Eucla basement) that separates the belt from the South Australian Craton. This basement constitutes the glue between the major building blocks of Proterozoic Australia, yet, its geological history is poorly understood. New drill cores penetrating the basement have intersected interlayered granitic and gabbroic rocks that yield U-Pb zircon dates that are dissimilar to any magmatic ages from units within the adjoining Albany-Fraser Orogen, with the exception of the youngest, 1190-1125 Ma magmatic suite. In addition, mantle-like hafnium and neodymium isotopic signatures indicate that the rocks of the Eucla basement are dominated by new juvenile addition, and may represent an allochthonous terrane of oceanic heritage. New ɛHf contour maps for the Albany-Fraser Orogen and Eucla basement highlight this difference. Time-slicing the isotopic dataset reveals a pattern of Palaeoproterozoic juvenile magmatism sub-perpendicular to the present day structural grain in the belt. If this marks the presence of an older lithospheric structure then it demonstrates the power that time-constrained isotopic mapping provides for illuminating lithospheric architecture through time. This may be

  7. Structural and geochronological studies on the Liba goldfield of the West Qinling Orogen, Central China

    Science.gov (United States)

    Zeng, Qingtao; McCuaig, T. Campbell; Hart, Craig J. R.; Jourdan, Fred; Muhling, Janet; Bagas, Leon

    2012-10-01

    The Liba goldfield, located to the northeast of the Zhongchuan Granite in the West Qinling Orogen (WQO) of mainland China, contains the largest known gold resource of 2.8 Moz in the Zhongchuan area. Devonian metasedimentary rocks host the structurally controlled gold mineralization, which is associated with silica-sericite-chlorite-carbonate alteration. Two major styles of mineralization occurred at the goldfield, which are disseminated sediment-hosted and quartz vein hosted types. Pyrite, arsenopyrite, and arsenian pyrite are major gold carriers and gold also occurs as native gold grains and electrum spatially associated with the sulfides. Numerous felsic/intermediate dykes have a similar structural control as the mineralization, and their contacts with host rocks are recognized as favorable zones for mineralization. Detailed fieldwork in conjunction with geochronological studies has helped to define the deformation history and gold metallogenesis of the goldfield. Three major phases of deformation have been recognized in the Zhongchuan area. The first deformation (D1) event was compressional in broadly a N-S orientation, the second (D2) event was also compressional and orientated in a NE-SW direction, and the third (D3) event was post-mineralization and was associated with the emplacement of barren calcite and anhydrite veins. Compression related to D2 is the key process that controlled the distribution of igneous dykes and gold mineralization in the Liba goldfield. Both igneous and hydrothermal fluids preferentially focused along dilational jogs under local trans-extension, which took place during the late stage of D2. Precise dating with high-resolution ion microprobe (SHRIMP) U-Pb on zircon and 40Ar/39Ar on muscovite, biotite, hornblende, and plagioclase of crosscutting pre-mineralization granitic porphyry and diorite dykes have constrained the mineralization age to after ca. 227 Ma. 40Ar/39Ar analysis of minerals formed in hydrothermal alteration zones

  8. Strain-related weakening in deep orogenic shear zones: what factors to consider?

    Science.gov (United States)

    Gerbi, C. C.; Culshaw, N.

    2011-12-01

    Quantifying strain-related weakening requires knowing which weakening processes dominate under various tectonic conditions. One commonly cited weakening factor is a change in phase topology, with a rock losing strength as weak phases become more interconnected. Accurate determinations of bulk strength requires knowledge of both the individual phase strengths and the control of microstructure on the bulk strength. Calculations described here focus first on the effects of microstructure and in particular phase topology. The calculations assume deformation by mechanisms that can be described simply by phase strengths and ignore mass transfer and grain boundary sliding. The initial motivating question is whether a constant value can adequately parameterize a given phase distribution and, if so, if that parameter value is predictable. Using a two-dimensional finite element calculation scheme for linearly viscous materials, it appears that constant values of the two microstructural parameters tested satisfactorily describe the bulk strength at viscosity contrasts less than ~50 for a given phase distribution and modal abundance. Neither tested parameter is constant with changes in mode. The values of the examined microstructural parameters do not appear to be predictable based on a qualitative analysis of the phase topology. Thus although a constant parameter value can adequately describe a given phase distribution, because that parameter is not determinable a priori, accurate measurement of the bulk strength of a composite requires a numerical calculation method. In natural samples from high strain zones from deep orogenic crust, weak phases are not necessarily interconnected and simply changing the shape preferred orientation of weak phases relative to the transport direction (i.e., transposition) can accommodate a moderate degree of weakening, particularly in the absence of large modal changes due to reactions. However, many natural shear zones also experience

  9. Orogenic-type copper-gold-arsenic-(bismuth) mineralization at Flatschach (Eastern Alps), Austria

    Science.gov (United States)

    Raith, Johann G.; Leitner, Thomas; Paar, Werner H.

    2015-10-01

    high Hg content (up to 11 mass %). The Cu-Au deposits in the Flatschach area show similarities with meso- to epizonal orogenic lode gold deposits regarding the geological setting, the structural control of mineralization, the type of alteration, the early (stage 1) sulfide assemblage and composition of gold. Unique about the Flatschach district is the lower-temperature overprint of copper arsenides (domeykite and koutekite) and copper sulfides (djurleite, yarrowite/spionkopite) on earlier formed sulfide mineralization. Based on mineralogical considerations temperature of stage 2 mineralization was between about 70 °C and 160 °C. Gold was locally mobilized during this low-temperature hydrothermal overprint as well as during stage 3 supergene oxidation and cementation processes.

  10. Geochemical modeling of orogenic gold deposit using PCANN hybrid method in the Alut, Kurdistan province, Iran

    Science.gov (United States)

    Mohammadzadeh, Mohammadjafar; Nasseri, Aynur

    2018-03-01

    In this paper stream sediments based geochemical exploration program with the aim of delineating potentially promising areas by a comprehensive stepwise optimization approach from univariate statistics, PCA, ANN, and fusion method PCANN were under taken for an orogenic gold deposit located in the Alut, Kurdistan province, NW of Iran. At first the data were preprocessed and then PCA were applied to determine the maximum variability directions of elements in the area. Subsequently the artificial neural network (ANN) was used for quick estimation of elemental concentration, as well as discriminating anomalous populations and intelligent determination of internal structure among the data. However, both the methods revealed constraints for modeling. To overcome the deficiency and shortcoming of each individual method a new methodology is presented by integration of both "PCA & ANN" referred as PCANN method. For integrating purpose, the detected PCs pertinent to ore mineralization selected and intruded to neural network structure, as a result different MLPs with various algorithms and structures were produced. The resulting PCANN maps suggest that the gold mineralization and its pathfinder elements (Au, Mo, W, Bi, Sb, Cu, Pb, Ag & As) are associated with metamorphic host rocks intruded by granite bodies in the Alut area. In addition, more concealed and distinct Au anomalies with higher intensity were detected, confirming the privileges of the method in evaluating susceptibility of the area in delineating new hidden potential zones. The proposed method demonstrates simpler network architecture, easy computational implementation, faster training speed, as well as no need to consider any primary assumption about the behavior of data and their probability distribution type, with more satisfactory predicting performance for generating gold potential map of the area. Comparing the results of three methods (PCA, ANN and PCANN), representing the higher efficiency and more

  11. Detrital zircon geochronology of pre- and syncollisional strata, Acadian orogen, Maine Appalachians

    Science.gov (United States)

    Bradley, Dwight C.; O'Sullivan, Paul B.

    2017-01-01

    northwest. Next, southeasterly parts of this succession were deformed in the Acadian orogeny, shedding detritus towards the northwest into what remained of the basin. Finally, by Pragian time, all strata in the Central Maine Basin had been deformed and detritus from this new source accumulated as the Tarratine Formation in a new incarnation of the foreland basin. Silurian-Devonian strata from the Central Maine Basin have similar detrital zircon age distributions to coeval rocks from the Arctic Alaska and Farewell terranes of Alaska and the Northwestern terrane of Svalbard. We suggest that these strata were derived from different segments of the 6500-km-long Appalachian-Caledonide orogen.

  12. Late Devonian Anoxia Events in the Central Asian Orogenic Belt: a Global Phenomenon

    Science.gov (United States)

    Carmichael, S. K.; Waters, J. A.; Suttner, T. J.; Kido, E.; DeReuil, A. A.; Moore, L. M.; Batchelor, C. J.

    2013-12-01

    Atmospheric CO2 values decreased dramatically during the Middle Devonian due to the rapid rise of land plants. These changing environmental conditions resulted in widespread anoxia and extinction events throughout the Late Devonian, including the critical Kellwasser and Hangenberg anoxia events, which are associated with major mass extinctions at both the beginning and end of the Famennian Stage of the Late Devonian. Fammenian sediments in northwestern Xinjiang Province, China, represent a highly fossiliferous shallow marine setting associated with a Devonian oceanic island arc complex. Analysis of multiple geochemical proxies (such as U/Th, Ba, normalized P2O5, V/Cr, Zr), magnetic susceptibility, and mineralogical data (biogenic apatite and pyrite framboids) indicates that these Famennian sequences record not only the Upper Kellwasser Anoxic Event at the Frasnian/Famennian (F/F) boundary but also the rebound from the F/F extinction event. Preliminary evidence suggests that the Hangenberg Anoxic Event can also be recognized in the same sequence, although our biostratigraphic control is less precise. Previous studies of the Kellwasser and Hangenberg Events have been performed on continental shelf environments of Laurussia, Gondwana, Siberia, and South China. The Devonian formations of northwest Xinjiang in this study, however, are part of the Central Asian Orogenic Belt (CAOB), which is thought to have formed as part of a complex amalgamation of intra-oceanic island arcs and continental fragments prior to the end of the latest Carboniferous. These results allow us to confirm the presence of the Kellwasser and Hangenberg Events in the open oceanic part of Paleotethys, indicating that both events were global in scope. The presence of an abundant diverse Famennian fauna between these anoxia/extinction events suggests that the shallow marine ecosystems in the CAOB were somewhat protected due to their tectonic location and relative isolation within an open ocean system

  13. Horizontal motions, bedrock incision, and the structure of relief in growing folds and orogens

    Science.gov (United States)

    Seixas, G.; Alejandre, J.; Hilley, G. E.

    2013-12-01

    Topographic divide asymmetry may arise from gradients in rock erodibility and orographic precipitation across a mountain belt, and/or tectonic displacement fields that uplift and translate rock horizontally during orogenesis. While simple models exploring relief in active orogens typically consider tectonic motions that are uniform and vertical, the displacement field at Earth's surface generated by slip on finite-length faults is inherently inhomogeneous and contains vertical and horizontal components, which may play an important role in divide asymmetry. In this study, we consider channel profiles that evolve according to the shear stress rule for bedrock fluvial erosion and that experience inhomogeneous horizontal and vertical components of tectonic motion. Dimensional analysis of our revised shear stress rule reveals a dimensionless coefficient that relates bedrock erodibility and basin geometry to slip rate on the underlying fault. We implement our model in a series of 1D non-dimensional numerical experiments that calculate river profile geometry on either side of a topographic divide that is free to advect through the model domain in response to horizontal motion. We drive the models with displacements calculated over a dipping, buried edge dislocation, and examine non-dimensional relief and divide asymmetry resulting from variations in fault dip, non-dimensional fault tip location and non-dimensional model extent. We find that asymmetry results from the full displacement field and from the vertical displacement field alone. Fault dip plays a strong role in the magnitude and direction of divide asymmetry, both in models that include the horizontal motions and those that neglect them. The greatest divide asymmetry resulting from the full displacement field is achieved over dislocations with shallow non-dimensional upper tip depths and small dip angles, although steeply-dipping faults produce asymmetry in the opposite direction. By setting the horizontal

  14. Hypothesizing Origin, Migration Routes and Distribution Patterns of Gymnosperms in Taiwan

    Directory of Open Access Journals (Sweden)

    Shing-Fan Huang

    2014-06-01

    Full Text Available Phytogeographical study of gymnosperms in Taiwan is carried out based on reviewing data gathered from published papers on fossils, phylogeny and phylogeography. Following questions are asked. (1 How is the high degree of endemism of gymnosperm flora of Taiwan derived? (2 How many source areas of gymnosperms in Taiwan are there? (3 Is there relation between distribution pattern of endemic gymnosperms in Taiwan and those of their sister species? (4 How do gymnosperms migrate to Taiwan?

  15. Evaluation of Freshwater Aquatic Resources and Stormwater Management at U.S. Naval Submarine Base, Bangor, Washington

    National Research Council Canada - National Science Library

    May, Christopher

    1997-01-01

    Surface and storm water conditions on the Naval Submarine Base (NSB), Bangor, Washington, are evaluated, and recommendations are made to improve water quality and enhance the ecological integrity of aquatic resources located on the base...

  16. Hydrothermal processes related to some Triassic and Jurassic submarine basaltic complexes in northeastern Hungary, the Dinarides and Hellenides

    National Research Council Canada - National Science Library

    Gabriella B Kiss; Ferenc Molnár; Ladislav A Palinkas

    2016-01-01

      Comparative studies on hydrothermal alteration of submarine peperitic basalt occurrences related to the Triassic early rifting of the Neotethys were carried out in various parts of the Dinarides and Hellenides...

  17. Volume transport data from a submarine cable in the Florida Strait from 1982 to 1998 (NODC Accession 0087879)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Daily mean volume transport data of the Florida Current collected with a submarine cable spanning from South Florida to the Grand Bahama Island in the Florida Strait...

  18. Linking time-Temperature history of the Aquitaine basin with post-orogenic evolution of the Pyrenees : new insights from borehole thermochronology

    Science.gov (United States)

    Fillon, Charlotte; Calassou, Sylvain; Mouthereau, Frédéric; Pik, Raphaël; Bellahsen, Nicolas; Gautheron, Cécile

    2017-04-01

    Within their sedimentary record, foreland basins document vertical movements of the lithosphere, climatic changes, paleogeograhic evolution but also history of exhumation of the adjacent mountain belt. Comparing vertical movements in a range and in its foreland is key to identify processes involved in growth and destruction of mountain belts. The Aquitaine basin, geomorphologically stable since the early Pyrenean orogenesis has the potential to help understanding the driving mechanisms during the late to post-orogenic phases, but the lack of outcrops makes the studies particularly difficult to achieve. To bring a new point of vue on the processes involved in the Cenozoic exhumation of this range, we present new low-Temperature thermochronology data from boreholes of the Aquitaine basin. With the objectives to study rift-related to post-orogenic processes, numerous low-T thermochronological ages ( 300 across the range) have been published, documenting pre-, syn- , and post-orogenic exhumation in the Pyrenees. Using thermal modeling of a new low-T database in the western Axial Zone, we show that a late Miocene (around 10 Ma) uplift occured in the western Pyrenees, which generalizes the post-orogenic signal already detected in the south central Pyrenees. In previous studies, we linked the post-orogenic exhumation in the Southern Pyrenees to the excavation of the foreland valleys caused by the opening of the endorheic Ebro basin towards the Mediterranean Sea. To the West, the tectonic out-of sequence reactivation of the Gavarnie thrust has been invoked to explain the late Miocene AHe ages in the Bielsa massif. These new data might lead us to re-think the causes for such an exhumation signal during "post-orogenic" times. We thus summarize all evidences for the post-orogenic phase and attempt to provide explanation for it: is exhumation driven by Aquitaine foreland basin evolution? Does it reflect a tectonic reactivation of the Pyrenees? or is the signature of a regional

  19. Submarine flow discharge changes as a way to explain incission-overspilling and other cycles in submarine channel sequences

    Science.gov (United States)

    Milana, J. P.; Kneller, B.; Dykstra, M.

    2009-04-01

    -stratification. The second bedform recognized is related to described macrodunes, and is comparable to large-scale antidunes, and produce tabular bodies with very subtle undulating structure. The third and perhaps more important is described as "gravel sheets" although they could be also low-relief gravel dunes developed during low-flow events, on top of the large-scale bedforms or directly over a flat gravelly bed. It is well known that bedforms produce the effect of delay averaged sediment velocity with respect to flow velocity, and thus we propose that this delay has an important geological effect as it creates a lag time between the onset of discharge increase and the time the channel bed reaches an equilibrium with the dominant flows. The effect of changes in the transport efficiency of submarine slope systems in the resulting depositional architecture is already known. However, we introduce here the concept of lagging the coarsest-grained fractions, delayed by the fact they involve in bedform building which move at lower velocities of the flows and hence allow the system to pass along a stage in which flows are big and fast, but the bed is not in equilibrium with them and as a result, canyoning may occur. These changes in external conditions (flow discharge) is likely to occur as a result of changes of turbid water near the slope by fluvial action and hence it would be t result of the interplay of river discharge and eustacy.

  20. Molluscan fauna of Gueishan Island, Taiwan

    Directory of Open Access Journals (Sweden)

    Chih-Wei Huang

    2013-01-01

    Full Text Available This dataset records the occurrence and inventory of molluscan fauna on Gueishan Island, the only active volcanic island in Taiwan, based on the literature survey and field investigation conducted between 2011 and 2012. The literature review involved seven studies published from 1934 to 2003, which collectively reported 112 species from 61 genera and 37 families of Mollusca on Gueishan Island. Through our field investigation, we identified 34 species from 28 genera and 23 families. Fourteen of these species were new records on Gueishan Island: Liolophura japonica, Lottia luchuana, Nerita costata, Nerita rumphii, Diplommatina suganikeiensis, Littoraria undulata, Solenomphala taiwanensis, Assiminea sp., Siphonaria laciniosa, Laevapex nipponica, Carychium hachijoensis, Succinea erythrophana, Zaptyx crassilamellata, and Allopeas pyrgula. In Total, there are 126 species from 71 genera and 45 families of Mollusca on Gueishan Island. These data have been published through GBIF [http://taibif.org.tw/ipt/resource.do?r=gueishan_island] and integrated into the Taiwan Malacofauna Database (http://shell.sinica.edu.tw/.

  1. Fetal exposure to environmental neurotoxins in Taiwan.

    Directory of Open Access Journals (Sweden)

    Chuen-Bin Jiang

    Full Text Available Mercury (Hg, lead (Pb, cadmium (Cd, and arsenic (As are recognized neurotoxins in children that particularly affect neurodevelopment and intellectual performance. Based on the hypothesis that the fetal basis of adult disease is fetal toxic exposure that results in adverse outcomes in adulthood, we explored the concentrations of key neurotoxins (i.e., Hg, Pb, Cd, and As in meconium to identify the risk factors associated with these concentrations. From January 2007 to December 2009, 545 mother-infant pairs were recruited. The geometric mean concentrations of Pb and As in the meconium of babies of foreign-born mothers (22.9 and 38.1 µg/kg dry weight, respectively were significantly greater than those of babies of Taiwan-born mothers (17.5 and 33.0 µg/kg dry weight, respectively. Maternal age (≥30 y, maternal education, use of traditional Chinese herbs during pregnancy, and fish cutlet consumption (≥3 meals/wk were risk factors associated with concentrations of key prenatal neurotoxins. The Taiwan government should focus more attention on providing intervention programs for immigrant mothers to help protect the health of unborn babies. Further investigation on how multiple neurotoxins influence prenatal neurodevelopment is warranted.

  2. Glacial landforms and relicts in the high mountains of Taiwan

    Science.gov (United States)

    Chu, H.-T.

    2009-04-01

    Glacial landforms and relicts in the high mountains of Taiwan Hao-tsu Chu Central Geological Survey, MOEA, Taiwan ROC Glacial landforms and relicts are well preserved in the high mountains of Taiwan although substantial orographic precipitation, periglacial, earthquakes, and surface erosion processes have been active ever since the retreat of the last glaciations. Variations of glacial landforms and relicts in the northern, central, and southern areas of Taiwan are attributed mainly to differences in lithology. Cirque glaciers and rectilinear trough valleys are distinctive glacial landforms in the Hseuhshan (3884m) and the Nanhutashan (3742m) area, respectively, in north-central Taiwan. Both of these areas are composed of hard and durable thick layers of meta-sandstone, meta-conglomerate, and quartzite with minor slate. Diagnostic glacial landform and glacial erosional features of streamlined bodies and striated moraines are widely distributed in the high ground above 3300m of the Hohuanshan (3416m) area and the Shangyang Shan (3496m) - Sanchar Shan (3602m) area, respectively in north-central and southern Taiwan. These two areas are mainly composed of weaker rocks of slate, schist with minor meta-sandstones. Whereas in central Taiwan, in the Mount Yushan (3952m) area, limited glacial landforms of polished and striated bedrock surface was found. The preservation of geomorphic surfaces with glacial erosional forms is highly favorable near or at the top of drainage divide where the effect of stream headward erosion, mass wasting, and surface creeping are not obvious.

  3. Simple models for the simulation of submarine melt for a Greenland glacial system model

    Directory of Open Access Journals (Sweden)

    J. Beckmann

    2018-01-01

    Full Text Available Two hundred marine-terminating Greenland outlet glaciers deliver more than half of the annually accumulated ice into the ocean and have played an important role in the Greenland ice sheet mass loss observed since the mid-1990s. Submarine melt may play a crucial role in the mass balance and position of the grounding line of these outlet glaciers. As the ocean warms, it is expected that submarine melt will increase, potentially driving outlet glaciers retreat and contributing to sea level rise. Projections of the future contribution of outlet glaciers to sea level rise are hampered by the necessity to use models with extremely high resolution of the order of a few hundred meters. That requirement in not only demanded when modeling outlet glaciers as a stand alone model but also when coupling them with high-resolution 3-D ocean models. In addition, fjord bathymetry data are mostly missing or inaccurate (errors of several hundreds of meters, which questions the benefit of using computationally expensive 3-D models for future predictions. Here we propose an alternative approach built on the use of a computationally efficient simple model of submarine melt based on turbulent plume theory. We show that such a simple model is in reasonable agreement with several available modeling studies. We performed a suite of experiments to analyze sensitivity of these simple models to model parameters and climate characteristics. We found that the computationally cheap plume model demonstrates qualitatively similar behavior as 3-D general circulation models. To match results of the 3-D models in a quantitative manner, a scaling factor of the order of 1 is needed for the plume models. We applied this approach to model submarine melt for six representative Greenland glaciers and found that the application of a line plume can produce submarine melt compatible with observational data. Our results show that the line plume model is more appropriate than the cone plume

  4. ESR dating of submarine hydrothermal activities using barite in sulfide deposition

    Science.gov (United States)

    Toyoda, S.; Fujiwara, T.; Ishibashi, J.; Isono, Y.; Uchida, A.; Takamasa, A.; Nakai, S.

    2012-12-01

    The temporal change of submarine hydrothermal activities has been an important issue in the aspect of the evolution of hydrothermal systems which is related with ore formation (Urabe, 1995) and biological systems sustained by the chemical species arising from hydrothermal activities (Macdonald et al., 1980). Determining the ages of the hydrothermal deposit will provide essential information on such studies. Dating methods using disequilibrium between radioisotopes such as U-Th method (e.g. You and Bickle, 1998), 226}Ra-{210Pb and 228}Ra-{228Th method (e.g. Noguchi et al., 2011) have been applied to date submarine hydrothermal deposits. ESR (electron spin resonance) dating method is commonly applied to fossil teeth, shells, and quartz of Quaternay period where the natural accumulated dose is obtained from the intensities of the ESR signals which are created by natural radiation. The natural dose is divided by the dose rate to the mineral/sample to deduce the age. Okumura et al., (2010) made the first practical application of ESR (electron spin resonance) dating technique to a sample of submarine hydrothermal barite (BaSO4) to obtain preliminary ages, where Kasuya et al. (1991) first pointed out that barite can be used for ESR dating. Knowing that ESR dating of barite is promising, in this paper, we will present how we have investigated each factor that contributes ESR dating of barite in submarine hydrothermal sulfide deposition. (1) The best ESR condition for measuring the SO3- signal in barite is with the microwave power of 1mW and modulation amplitude of 0.1mT. (2) As results of heating experiments, the signal was found to be stable for the dating age range of several thousands. (3) 226Ra replacing Ba in barite is the source of the radiation. The amount of radioactive elements in sulfide mineral surrounding barite is negligible. (4) The external radiation from the sea water is negligible even in the submarine hydrothermal area where the radiation level is much

  5. Ages and origin of felsic rocks from the Eastern Erenhot ophiolitic complex, southeastern Central Asian Orogenic Belt, Inner Mongolia China

    Science.gov (United States)

    Yang, Jinfu; Zhang, Zhicheng; Chen, Yan; Yu, Haifei; Qian, Xiaoyan

    2017-08-01

    The Central Asian Orogenic Belt (CAOB) is known for its massive Phanerozoic generation of juvenile crust. The tectonic evolution of the CAOB during the late Paleozoic era is still debated. The Eastern Erenhot ophiolite complex (EOC) has been recognized as one of the numerous late Paleozoic ophiolitic blocks in the southeastern part of the CAOB. Zircon U-Pb dating on rhyolite and plagiogranite from the EOC yielded a tight range of ages from 360 to 348 Ma, indicating that the complex formed in the early Carboniferous. The primitive mantle-normalized spider diagram of rhyolites (εNd(t) values of +6.8 and +7) and basalts almost overlaps. Such rhyolites may have been derived from partial melting of juvenile basaltic rocks during the initial opening of the Erenhot-Hegenshan oceanic basin. All of the plagiogranites exhibit similar trace element behaviours of High Field-Strength Elements, such as U, Zr and Hf, and Large Ion Lithophile Elements, such as Ba and Rb, to these of gabbros. These plagiogranites were considered products of episodes of partial melting of hydrous gabbros during ocean floor spreading. We conclude that the northern subduction of the Paleo-Asian Ocean stopped before 360 Ma and the southeastern CAOB experienced extension during the late Paleozoic era. The Erenhot-Hegenshan Ocean, which is comparable to the present Red Sea, originated from syn-collisional crustal thickening, subsequent lithosphere extension, and upwelling of the asthenosphere during orogenic quiescence with an age of 20 Ma.

  6. Pliocene-Quaternary orogenic systems in Central Mediterranean: The Apulia-Southern Apennines-Tyrrhenian Sea example

    Science.gov (United States)

    Milia, Alfonsa; Torrente, Maurizio M.; Iannace, Pietro

    2017-08-01

    In the Central Mediterranean the Africa-Eurasia convergence led to the development of complex orogenic systems and back-arc basins. Throughout Pliocene-Quaternary times the Southern Apennines accretionary prism migrated toward the Apulia foreland and, contemporaneously, the Tyrrhenian Sea back-arc basin opened. In this study, we investigated the offshore of the southern Apulia foreland and the Southern Apennines. Using seismic reflection profiles and well data in a dedicated GIS software, we made a detailed stratigraphic analysis, reconstructed the structural pattern, and built 2-D geological models of the main geological surfaces. The structure of the Apulia region formed during two main tectonic stages: lower Pleistocene complex extensional faulting developed in a transtensional regime and middle-upper Pleistocene transpression/shortening. The Southern Apennines accretionary prism developed through the Pliocene-early lower Pleistocene and was overprinted by late lower Pleistocene-middle Pleistocene NW-SE sinistral faults. Through linking new data from the accretionary prism and the foreland with previous information from the Tyrrhenian Sea back-arc, we provide an original interpretation for the relationships between the various provinces that make the Central Mediterranean crustal puzzle and reconstruct the main phases of the evolution of its Pliocene-Quaternary orogenic cycle. We recognized collisional stages of uncoupled plates, followed by late lower-middle Pleistocene postcollisional stages of coupled continental plates. This Pleistocene plate reorganization of Central Mediterranean was probably due to the rupture of the Apulia/Ionian slab or to NNW intraplate shortening transmitted from Africa.

  7. Changes to United States Navy Submarine Design and Construction during World War I, as Determined by the General Board.

    Science.gov (United States)

    2017-06-09

    and influence of operational doctrine that led to significant innovation during the interwar period. 15. SUBJECT TERMS Anti-Submarine Warfare (ASW...naval technology and influence of operational doctrine that led to significant innovation during the interwar period. v ACKNOWLEDGMENTS Many...Russian government Anti Access and Area Denial programs, it can be seen how submarine design and construction remains as important today as when Germany

  8. Cool Season Paleotemperatures at Tree Line in Taiwan

    Science.gov (United States)

    Wright, W. E.; Chan, M.

    2011-12-01

    Taiwan has over 200 mountains whose peaks exceed 3,000 meters in elevation. Despite straddling the Tropic of Cancer, the higher peaks have snow and freezing temperatures every winter. Trees growing above 3,500 meters show clear temperature variation, even producing frost rings. Yet unlike temperate tree-line species, with their warm season temperature signal, trees growing at Taiwan's tree line show sensitivity to cool season temperatures. Juniperus squamata growing above 3,500 meters in central Taiwan have ring width time series that commonly exceed 600 years. Presented are the first dendroclimatological analyses from Taiwanese Juniperus squamata.

  9. Sand provenance documents continuing accretion of the pro-wedge and erosional unroofing of the retro-wedge during arc-continent collision (Taiwan)

    Science.gov (United States)

    Garzanti, Eduardo; Padoan, Marta; Resentini, Alberto; Vezzoli, Giovanni; Castelltort, Sebastien; Tien-Shun Lin, Andrew

    2014-05-01

    The Taiwan doubly-vergent orogenic wedge developed during collision between the Luzon volcanic arc and the Chinese passive continental margin since the late Miocene (Byrne et al., 2011). In the east, the Coastal Range represents the northernmost extension of the Luzon arc and includes Neogene volcanic rocks and Plio-Pleistocene siliciclastic deposits. West of the plate boundary, running along the Longitudinal Valley, the Central Range includes polymetamorphic rocks (Tananao Complex) and a Slate Belt (Backbone Range and Hsuehshan Range). Farther to the west, the Western Foothills are a fold-thrust belt incorporating Oligo-Miocene sediments of the Chinese margin and younger foreland-basin deposits. High-resolution framework-petrography and heavy-mineral analyses were carried out on 106 samples collected from major rivers and beaches all around Taiwan in October 2012. The Coastal Range sheds feldspatho-lithic volcaniclastic sands including rich clinopyroxene-hypersthene suites with kaersutitic hornblende. Recycling of Plio-Pleistocene siliciclastics produces quartzo-lithic sands with cellular serpentinite and poor suites including hypersthene, epidote, clinopyroxene, kaersutitic hornblende and rare Cr-spinel. Similar mineralogy characterizes detritus from the Liji Mélange. Sands from the Tananao Complex are quartzo-lithic metamorphiclastic with common marble grains, sporadic metabasite, and moderately rich epidote-hornblende suites. Sands from the Slate Belt are invariably quartzo-lithic with very poor zircon-tourmaline suites. Phyllite and slate grains dominate in the east (Yuli Belt), slate grains in the middle (Backbone Range), and shale/siltstone and slate grains in the northwest (Hsuehshan Range). Neogene strata of the foothills shed litho-quartzose sands with poor suites including zircon, tourmaline, and garnet. Sands from the Tatung volcano are feldspatho-quartzo-lithic with extremely rich hypersthene-clinopyroxene suites including kaersutitic hornblende. The

  10. Tectono-stratigraphic evolution of a Neogene oblique extensional orogenic basin, southeast Spain

    Science.gov (United States)

    Hodgson, David Mark

    The Tabernas-Sorbas Basin is one of several elongate intramontane basins in the Betic Cordillera that formed on stretched metamorphic rocks, formed during Alpine African-Iberian compression. This study focuses on the early tectono-stratigraphic evolution of the basin from the late Serravallian to the early Messinian (12-6 Ma). During the latest Serravallian, the exhumation and erosion of the hinterland with rapid east-to-west cooling and uplift of the Nevado-Filabride Complex, was reflected by an abrupt east-to-west increase in coarse-grained sediment flux with the establishment of fan-delta sedimentation (Umbria Formation, Pollo Member, and Rambla de Indalecio Member). A major period of tectonic reorganisation in the earliest Tortonian led to the formation of a regional unconformity, a change in palaeoslope and the influx of Nevado-Filabride rock-types (Lomas Colorada Member). Continued basin subsidence, controlled by an anticlockwise change in extension (ENE-WSW), led to the deposition of submarine fans (Mizala Member) and marls with interbedded contained-flow turbidites (the Lucainena Member). The westward-stepping depocentre and a syn-sedimentary tectonic transport direction about the NE-SW, indicate subsidence was controlled by dextral oblique-extension. N-directed movement and anticlockwise rotation of the Alhamilla block led to the compressional deformation at the SE margin with low-angle normal faults reactivated as syn-sedimentary thrust faults and the formation of an angular unconformity. Growth of NE-SW trending anticlines and synclines, and a reduced basin floor gradient changed the bypassing sedimentary system (Unit A) to an aggradational, ponded system (Unit B and C). Dextral oblique-compressional conditions in the east, therefore, were coeval with a dextral oblique-extensional regime in the west during the latest Tortonian. Ponded sheet turbidites, intercalated with rare seismites, healed the topographically complex basin-floor (Unit D) and were

  11. Representing distributed cognition in complex systems: how a submarine returns to periscope depth.

    Science.gov (United States)

    Stanton, Neville A

    2014-01-01

    This paper presents the Event Analysis of Systemic Teamwork (EAST) method as a means of modelling distributed cognition in systems. The method comprises three network models (i.e. task, social and information) and their combination. This method was applied to the interactions between the sound room and control room in a submarine, following the activities of returning the submarine to periscope depth. This paper demonstrates three main developments in EAST. First, building the network models directly, without reference to the intervening methods. Second, the application of analysis metrics to all three networks. Third, the combination of the aforementioned networks in different ways to gain a broader understanding of the distributed cognition. Analyses have shown that EAST can be used to gain both qualitative and quantitative insights into distributed cognition. Future research should focus on the analyses of network resilience and modelling alternative versions of a system.

  12. Physical activity aboard nuclear submarines as measured by pedometry. Interim report

    Energy Technology Data Exchange (ETDEWEB)

    Bondi, K.R.; Dougherty, J.H.

    1985-05-23

    Activity levels of 44 submarines were monitored before and during a fleet ballistic missile submarine patrol. These levels were determined by use of a pedometer worn on the hip. Readings were obtained daily and recorded in a log as miles walked. Through extensive preliminary testing it was determined that the miles unit was useless, due to variability in the sensitivity of the pedometer pendulum movements and the inability to determine a meaningful stride length . Results for any combination of pedometer/user were, however, repeatable. For lack of a better term, results are reported in miles per day and are as follows: Control = 2.11 + or - 0.32 and Underway = 1.01 + or - 0.27 (P<.05 Student T). This reduction of more than 50% in activity level may in part be responsible for the physical deconditioning observed during the course of a 40-70 day submergence period.

  13. Submarine groundwater discharge into the near-shore zone of the Great Barrier Reef, Australia

    Energy Technology Data Exchange (ETDEWEB)

    Stieglitz, Thomas [Marine Geophysical Laboratory, School of Mathematical and Physical Sciences, James Cook University, Townsville QLD 4811 (Australia) and Australian Institute of Marine Science, Townsville QLD 4810 (Australia)]. E-mail: thomas.stieglitz@jcu.edu.au

    2005-07-01

    Along the tropical coastline of the Great Barrier Reef (GBR) region, little is known to date about submarine groundwater discharge (SGD) into the near-shore ocean. In an oceanographic sense, SGD consists of freshwater flow from land as well as seawater circulated through sediments. Recent radiochemical and geophysical studies, using the tracer {sup 222}Rn and apparent ground conductivity respectively, provide evidence for SGD to occur in a variety of hydrogeological settings. In this paper, a non-quantitative overview of different settings of SGD in the region is presented: (1) recirculation of seawater through animal burrows in mangrove forests, (2) freshwater SGD from unconfined aquifers as a narrow coastal fringe of freshwater along Wet Tropics beaches, (3) SGD from coastal dune systems in form of localised freshwater springs in the intertidal zone, (4) inner-shelf SGD from confined submarine aquifer systems comprised of riverine paleochannels incised into the shelf.

  14. Research on Fairing design and CFD Analysis of Submarine Pipeline Inspection ARV

    Directory of Open Access Journals (Sweden)

    Jin Xiaojian

    2017-01-01

    Full Text Available Along with the fast development of the ocean exploitation, the cost-effective requirement of autonomous & remotely operated vehicle (ARV, which can perform more complicated missions such as the oil exploitation and the inspection of the submarine pipeline is more urgent. The submarine pipeline inspection ARV can help us better understand, protect and efficiently utilize them for human welfare. Fairing design of a new detection ARV are introduced in this paper. In order to select an appropriate thruster that will achieve the required speed of the ARV, the ANSYS-CFX tools are used to predicted the drag force. The CFD results reveal the distribution of velocity and pressure values of the ARV. In order to verify the CFD modeling process, a towed body was developed and analyzed, compared against the corresponding physical test data.

  15. Management of ulcerative colitis in Taiwan: consensus guideline of the Taiwan Society of Inflammatory Bowel Disease.

    Science.gov (United States)

    Wei, Shu-Chen; Chang, Ting-An; Chao, Te-Hsin; Chen, Jinn-Shiun; Chou, Jen-Wei; Chou, Yenn-Hwei; Chuang, Chiao-Hsiung; Hsu, Wen-Hung; Huang, Tien-Yu; Hsu, Tzu-Chi; Lin, Chun-Chi; Lin, Hung-Hsin; Lin, Jen-Kou; Lin, Wei-Chen; Ni, Yen-Hsuan; Shieh, Ming-Jium; Shih, I-Lun; Shun, Chia-Tung; Tsang, Yuk-Ming; Wang, Cheng-Yi; Wang, Horng-Yuan; Weng, Meng-Tzu; Wu, Deng-Chyang; Wu, Wen-Chieh; Yen, Hsu-Heng; Wong, Jau-Min

    2017-07-01

    Ulcerative colitis (UC) is an inflammatory bowel disease characterized by chronic mucosal inflammation of the colon, and the prevalence and incidence of UC have been steadily increasing in Taiwan. A steering committee was established by the Taiwan Society of Inflammatory Bowel Disease to formulate statements on the diagnosis and management of UC taking into account currently available evidence and the expert opinion of the committee. Accurate diagnosis of UC requires thorough clinical, endoscopic, and histological assessment and careful exclusion of differential diagnoses, particularly infectious colitis. The goals of UC therapy are to induce and maintain remission, reduce the risk of complications, and improve quality of life. As outlined in the recommended treatment algorithm, choice of treatment is dictated by severity, extent, and course of disease. Patients should be evaluated for hepatitis B virus and tuberculosis infection prior to immunosuppressive treatment, especially with steroids and biologic agents, and should be regularly monitored for reactivation of latent infection. These consensus statements are also based on current local evidence with consideration of factors, and could be serve as concise and practical guidelines for supporting clinicians in the management of UC in Taiwan.

  16. Management of Crohn's disease in Taiwan: consensus guideline of the Taiwan Society of Inflammatory Bowel Disease.

    Science.gov (United States)

    Wei, Shu-Chen; Chang, Ting-An; Chao, Te-Hsin; Chen, Jinn-Shiun; Chou, Jen-Wei; Chou, Yenn-Hwei; Chuang, Chiao-Hsiung; Hsu, Wen-Hung; Huang, Tien-Yu; Hsu, Tzu-Chi; Lin, Chun-Chi; Lin, Hung-Hsin; Lin, Jen-Kou; Lin, Wei-Chen; Ni, Yen-Hsuan; Shieh, Ming-Jium; Shih, I-Lun; Shun, Chia-Tung; Tsang, Yuk-Ming; Wang, Cheng-Yi; Wang, Horng-Yuan; Weng, Meng-Tzu; Wu, Deng-Chyang; Wu, Wen-Chieh; Yen, Hsu-Heng; Wong, Jau-Min

    2017-07-01

    Crohn's disease (CD) is a chronic relapsing and remitting inflammatory disease of the gastrointestinal tract. CD is rare in Taiwan and other Asian countries, but its prevalence and incidence have been steadily increasing. A steering committee was established by the Taiwan Society of Inflammatory Bowel Disease to formulate statements on the diagnosis and management of CD taking into account currently available evidence and the expert opinion of the committee. Thorough clinical, endoscopic, and histological assessments are required for accurate diagnosis of CD. Computed tomography and magnetic resonance imaging are complementary to endoscopic evaluation for disease staging and detecting complications. The goals of CD management are to induce and maintain remission, reduce the risk of complications, and improve quality of life. Corticosteroids are the mainstay for inducing re-mission. Immunomodulating and biologic therapies should be used to maintain remission. Patients should be evaluated for hepatitis B virus and tuberculosis infection prior to treatment and receive regular surveillance for cancer. These consensus statements are based on current local evidence with consideration of factors, and could be serve as concise and practical guidelines for supporting clinicians in the management of patients with CD in Taiwan.

  17. Management of Crohn's disease in Taiwan: consensus guideline of the Taiwan Society of Inflammatory Bowel Disease

    Directory of Open Access Journals (Sweden)

    Shu-Chen Wei

    2017-07-01

    Full Text Available Crohn's disease (CD is a chronic relapsing and remitting inflammatory disease of the gastrointestinal tract. CD is rare in Taiwan and other Asian countries, but its prevalence and incidence have been steadily increasing. A steering committee was established by the Taiwan Society of Inflammatory Bowel Disease to formulate statements on the diagnosis and management of CD taking into account currently available evidence and the expert opinion of the committee. Thorough clinical, endoscopic, and histological assessments are required for accurate diagnosis of CD. Computed tomography and magnetic resonance imaging are complementary to endoscopic evaluation for disease staging and detecting complications. The goals of CD management are to induce and maintain remission, reduce the risk of complications, and improve quality of life. Corticosteroids are the mainstay for inducing re-mission. Immunomodulating and biologic therapies should be used to maintain remission. Patients should be evaluated for hepatitis B virus and tuberculosis infection prior to treatment and receive regular surveillance for cancer. These consensus statements are based on current local evidence with consideration of factors, and could be serve as concise and practical guidelines for supporting clinicians in the management of patients with CD in Taiwan.

  18. From waste minimization to ISO 14000: Taiwan`s experience and prospects

    Energy Technology Data Exchange (ETDEWEB)

    Wen-Huei Chen; Wain-Sun Hou [China Technical Consultants, Inc., Taipei (Taiwan, Province of China)

    1996-12-31

    Taiwan has completed a very successful five-year industrial waste minimization (IWM) demonstration and promotion project sponsored by the government. From 1990 to 1995, the project successfully disseminated the IWM concept of pollution prevention (P2) to industries. It effectively reduced industrial waste while significantly benefitting the economy by assisting industries in implementing in-plant IWM programs. In July 1995, the second stage of the five-year IWM and ISO 14000 promotion project was initiated for further promoting the IWM, P2, and cleaner production and, in particular, coping with the upcoming international environmental management standards (ISO 14000). To assist industries in establishing an environmental management system (EMS) and accumulating related experience, an EMS pilot demonstration project of five model industries and an ISO 14001 EMS demonstration and promotion project for 22 factories in 13 industries were initiated in October 1995 and August 1996, respectively. These projects can assist Taiwan`s industries in changing the constitution of their enterprises, enhancing competition in the international market, and helping our nation achieve the forerunner`s profits in sustainable development. 9 refs., 3 figs.

  19. Management of Crohn's disease in Taiwan: consensus guideline of the Taiwan Society of Inflammatory Bowel Disease

    Science.gov (United States)

    Wei, Shu-Chen; Chang, Ting-An; Chao, Te-Hsin; Chen, Jinn-Shiun; Chou, Jen-Wei; Chou, Yenn-Hwei; Chuang, Chiao-Hsiung; Hsu, Wen-Hung; Huang, Tien-Yu; Hsu, Tzu-Chi; Lin, Chun-Chi; Lin, Hung-Hsin; Lin, Jen-Kou; Lin, Wei-Chen; Ni, Yen-Hsuan; Shieh, Ming-Jium; Shih, I-Lun; Shun, Chia-Tung; Tsang, Yuk-Ming; Wang, Cheng-Yi; Wang, Horng-Yuan; Weng, Meng-Tzu; Wu, Deng-Chyang; Wu, Wen-Chieh; Yen, Hsu-Heng

    2017-01-01

    Crohn's disease (CD) is a chronic relapsing and remitting inflammatory disease of the gastrointestinal tract. CD is rare in Taiwan and other Asian countries, but its prevalence and incidence have been steadily increasing. A steering committee was established by the Taiwan Society of Inflammatory Bowel Disease to formulate statements on the diagnosis and management of CD taking into account currently available evidence and the expert opinion of the committee. Thorough clinical, endoscopic, and histological assessments are required for accurate diagnosis of CD. Computed tomography and magnetic resonance imaging are complementary to endoscopic evaluation for disease staging and detecting complications. The goals of CD management are to induce and maintain remission, reduce the risk of complications, and improve quality of life. Corticosteroids are the mainstay for inducing re-mission. Immunomodulating and biologic therapies should be used to maintain remission. Patients should be evaluated for hepatitis B virus and tuberculosis infection prior to treatment and receive regular surveillance for cancer. These consensus statements are based on current local evidence with consideration of factors, and could be serve as concise and practical guidelines for supporting clinicians in the management of patients with CD in Taiwan. PMID:28670226

  20. Sediment community responses to marine vs. terrigenous organic matter in a submarine canyon

    OpenAIRE

    Hunter, W. R.; Jamieson, A; Huvenne, V. A. I.; Witte, U

    2013-01-01

    The Whittard Canyon is a branching submarine canyon on the Celtic continental margin, which may act as a conduit for sediment and organic matter (OM) transport from the European continental slope to the abyssal sea floor. In situ stable-isotope labelling experiments were conducted in the eastern and western branches of the Whittard Canyon, testing short-term (3–7 days) responses of sediment communities to deposition of nitrogen-rich marine (Thalassiosira weissflogii) and ni...