LIVIVO - Search results -

Search results

Result 1 - 9 of total 9

Search options

Article ; Online: Mantle fluids associated with crustal-scale faulting in a continental subduction setting, Taiwan

Ai-Ti Chen / Chuan-Chou Shen / Timothy B. Byrne / Yuji Sano / Naoto Takahata / Tsanyao Frank Yang / Yunshuen Wang

Scientific Reports, Vol 9, Iss 1, Pp 1-

2019 Volume 7

Abstract: Abstract We report noble gas signatures of groundwater, hot springs, and bedrock samples from a major fault system that separates regional-scale blocks of accreted, continental materials in southern Taiwan. Despite the continental setting, the isotopic ... ...

Abstract	Abstract We report noble gas signatures of groundwater, hot springs, and bedrock samples from a major fault system that separates regional-scale blocks of accreted, continental materials in southern Taiwan. Despite the continental setting, the isotopic signatures argue for the presence of mantle derived fluids, suggesting that the active fault system is deep-seated. This is consistent with deep, non-volcanic tremors identified in the same area. We speculate that the mantle fluids are escaping along a crustal-scale fault marked by clusters of non-volcanic tremors directly beneath the southern Central Range. The evidence of these tremors and electrical conductivity anomalies along the strike of the fault recognized previously correlated up dip with the surface trace of a major active fault support the hypothesis.
Keywords	Medicine ; R ; Science ; Q
Language	English
Publishing date	2019-07-01T00:00:00Z
Publisher	Nature Publishing Group
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article ; Online: Estimating the composition of gas hydrate using 3D seismic data from Penghu Canyon, offshore Taiwan

Sourav Kumar Sahoo / Wu-Cheng Chi / Wei-Chung Han / Liwen Chen / Char-Shine Liu / Yunshuen Wang

Terrestrial, Atmospheric and Oceanic Sciences, Vol 29, Iss 2, Pp 105-

2018 Volume 115

Abstract: Direct measurements of gas composition by drilling at a few hundred meters below seafloor can be costly, and a remote sensing method may be preferable. The hydrate occurrence is seismically shown by a bottom-simulating reflection (BSR) which is generally ...

Abstract	Direct measurements of gas composition by drilling at a few hundred meters below seafloor can be costly, and a remote sensing method may be preferable. The hydrate occurrence is seismically shown by a bottom-simulating reflection (BSR) which is generally indicative of the base of the hydrate stability zone. With a good temperature profile from the seafloor to the depth of the BSR, a near-correct hydrate phase diagram can be calculated, which can be directly related to the hydrate composition. However, in the areas with high topographic anomalies of seafloor, the temperature profile is usually poorly defined, with scattered data. Here we used a remote method to reduce such scattering. We derived gas composition of hydrate in stability zone and reduced the scattering by considering depth-dependent geothermal conductivity and topographic corrections. Using 3D seismic data at the Penghu canyon, offshore SW Taiwan, we corrected for topographic focusing through 3D numerical thermal modeling. A temperature profile was fitted with a depth-dependent geothermal gradient, considering the increasing thermal conductivity with depth. Using a pore-water salinity of 2%, we constructed a gas hydrate phase model composed of 99% methane and 1% ethane to derive a temperature depth profile consistent with the seafloor temperature from in-situ measurements, and geochemical analyses of the pore fluids. The high methane content suggests predominantly biogenic source. The derived regional geothermal gradient is 40Â°C km-1. This method can be applied to other comparable marine environment to better constrain the composition of gas hydrate from BSR in a seismic data, in absence of direct sampling.
Keywords	Geography (General) ; G1-922 ; Geology ; QE1-996.5
Subject code	550
Language	English
Publishing date	2018-01-01T00:00:00Z
Publisher	Chinese Geoscience Union
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article ; Online: Shallow Crustal Thermal Structures of Central Taiwan Foothills Region

Shao-Kai Wu / Wu-Cheng Chi / Shih-Meng Hsu / Chien-Chung Ke / Yunshuen Wang

Terrestrial, Atmospheric and Oceanic Sciences, Vol 24, Iss 4-2, p

2013 Volume 695

Abstract: Crustal thermal structures are closely related to metamorphism, rock rheology, exhumation processes, hydrocarbon maturation levels, frictional faulting and other processes. Drilling is the most direct way to access the temperature fields in the shallow ... ...

Abstract	Crustal thermal structures are closely related to metamorphism, rock rheology, exhumation processes, hydrocarbon maturation levels, frictional faulting and other processes. Drilling is the most direct way to access the temperature fields in the shallow crust. However, a regional drilling program for geological investigation is usually very expensive. Recently, a large-scale in-situ investigation program in the Western Foothills of Central Taiwan was carried out, providing a rare opportunity to conduct heat flow measurements in this region where there are debates as to whether previous measured heat flows are representative of the thermal state in this region. We successfully collected 28 geothermal gradients from these wells and converted them into heat flows. The new heat flow dataset is consistent with previous heat flows, which shows that the thermal structures of Central Taiwan are different from that of other subduction accretionary prisms. We then combine all the available heat flow information to analyze the frictional parameters of the Chelungpu fault zone that ruptured during the 1999, Chi-Chi, Taiwan, earthquake. The heat flow dataset gave consistent results compared with the frictional parameters derived from another independent study that used cores recovered from the Chelungpu fault zone at depth. This study also shows that it is suitable for using heat-flow data obtained from shallow subsurface to constrain thrusting faulting parameters, similar to what had been done for the strike-slip San Andreas Fault in California. Additional fieldworks are planned to study heat flows in other mountainous regions of Taiwan for more advanced geodynamic modeling efforts.
Keywords	Crustal thermal structures ; Heat flow ; Geothermal gradients ; Frictional effects ; Geography (General) ; G1-922 ; Geology ; QE1-996.5
Subject code	550
Language	English
Publishing date	2013-01-01T00:00:00Z
Publisher	Chinese Geoscience Union
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article ; Online: Early diagenesis and carbon remineralization in young rift sediment of the Southern Okinawa Trough

Yu-Shih Lin / Huei-Ting Lin / Bo-Shian Wang / Shein-Fu Wu / Pei-Ling Wang / Chih-Lin Wei / Hsiao-Fen Lee / Tefang Lan / Wei-Jen Huang / Song-Chuen Chen / Yunshuen Wang / Chih-Chieh Su

Terrestrial, Atmospheric and Oceanic Sciences, Vol 30, Iss 5, Pp 633-

2019 Volume 647

Abstract: With large topographic gradients, rifted basins serve as efficient traps for particulate matter from adjacent lands and the ocean surface. However, the fate of organic carbon in the sediment, mostly unaltered by the hydrothermal activities known to occur ...

Abstract	With large topographic gradients, rifted basins serve as efficient traps for particulate matter from adjacent lands and the ocean surface. However, the fate of organic carbon in the sediment, mostly unaltered by the hydrothermal activities known to occur in young rifts, remains poorly understood. In this study, we present an examination of diagenetic activities and carbon remineralization based on the first complete suite of pore-water data of sediment marginally affected by hydrothermal activities in the Southern Okinawa Trough (SOT). The sediment showed an oxygen penetration depth of 1 cm, consumption of NO3- in the top 1 cm, smeared profiles of Mn2+ and Fe2+ with the latter reaching up to 450 μmol L-1, and relatively unchanged SO42- concentrations with depth. Net production rates of dissolved species resolved from pore-water profiles provide an estimate of 1.68 ± 0.21 mmol C m-2 d-1 as the total carbon remineralization rate in the upper 30 cm sediment column, with aerobic carbon oxidation being the major pathway. The rate, one order of magnitude lower than that of the adjacent East China Sea, is attributed to the lower bottom-water temperature and carbon flux in the trough. The high carbon burial efficiency of SOT (68% of carbon reaching the seafloor and processed thereunder) reflects the combined effects of small mountain rivers and rifting-induced particle trapping.
Keywords	Geography (General) ; G1-922 ; Geology ; QE1-996.5
Subject code	550 ; 551
Language	English
Publishing date	2019-01-01T00:00:00Z
Publisher	Chinese Geoscience Union
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article ; Online: Hydrothermal activity revealed by rock magnetic anomaly from core sediments in the southern Okinawa Trough

Yin-Sheng Huang / Chih-Chieh Su / Wen-Bin Doo / Shu-Kun Hsu / Chin-Hui Tsai / Hsueh-Fen Wang / Shiao-Shan Lin / Chin-Wei Liang / Jing-Yi Lin / Jui-Er Chen / Yi-Jung Lin / Yunshuen Wang

Terrestrial, Atmospheric and Oceanic Sciences, Vol 30, Iss 5, Pp 685-

2019 Volume 694

Abstract: The southern Okinawa Trough has been widely considered an important area with hydrothermal activity. Several active hydrothermal fields have been reported, especially around the Yonaguni Knoll IV. In this study, we collected marine sediment cores around ... ...

Abstract	The southern Okinawa Trough has been widely considered an important area with hydrothermal activity. Several active hydrothermal fields have been reported, especially around the Yonaguni Knoll IV. In this study, we collected marine sediment cores around the Yonaguni Knoll IV by using the R/V Ocean Research 1. Core sites with and without gas disturbance were selected based on the single-beam bathymetry (Chirp) by using the onboard echo sounder system. For the sites away from gas disturbance, which are generally considered showing the background situation in the southern Okinawa Trough, variations of the magnetic susceptibility in these cores are relatively stable with values about between 20 × 10-5 and 60 × 10-5 SI. As for the sites with clear gas-features detected by the Chirp sonar, the signature with dramatically changing magnetic susceptibility is observed in the cores. In general, gasfeatures are considered linking to the hydrothermal activity in the southern Okinawa Trough. Magnetic signature with such abruptly changing magnetic susceptibility could also be considered being caused by authigenic iron sulfides associated with the hydrothermal alternation. Therefore, the rock magnetic anomaly could be suggested as an indicator revealing the hydrothermal activity in the southern Okinawa Trough.
Keywords	Geography (General) ; G1-922 ; Geology ; QE1-996.5
Subject code	550
Language	English
Publishing date	2019-01-01T00:00:00Z
Publisher	Chinese Geoscience Union
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article ; Online: Distribution and Characters of Gas Hydrate Offshore of Southwestern Taiwan

Char-Shine Liu / Philippe Schnurle / Yunshuen Wang / San-Hsiung Chung / Song-Chuen Chen / Ta-Hen Hsiuan

Terrestrial, Atmospheric and Oceanic Sciences, Vol 17, Iss 4, p

2006 Volume 615

Abstract: 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 ... ...

Abstract	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 different tectonic settings.
Keywords	Gas hydrates ; Bottom simulating reflectors ; Marine seismic reflection data ; Passive and convergent boundary ; Southwestern Taiwan ; Geography (General) ; G1-922 ; Geology ; QE1-996.5
Subject code	550
Language	English
Publishing date	2006-01-01T00:00:00Z
Publisher	Chinese Geoscience Union
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article ; Online: Methane Venting in Gas Hydrate Potential Area Offshore of SW Taiwan

Tsanyao Frank Yang / Pei-Chuan Chuang / Saulwood Lin / Ju-Chin Chen / Yunshuen Wang / San-Hsiung Chung

Terrestrial, Atmospheric and Oceanic Sciences, Vol 17, Iss 4, p

Evidence of Gas Analysis of Water Column Samples

2006 Volume 933

Abstract: Water column samples were collected systematically in several potential gas hydrate areas offshore of SW Taiwan for analysis of dissolved gases. Some these samples show unusually high dissolved methane concentrations at sites A, B, C, and H of cruise ORI- ...

Abstract	Water column samples were collected systematically in several potential gas hydrate areas offshore of SW Taiwan for analysis of dissolved gases. Some these samples show unusually high dissolved methane concentrations at sites A, B, C, and H of cruise ORI-765. The profiles of helium concentrations in the dissolved gases of the water column also exhibit consistent results with an increasing trend toward the seafloor. The 3He/4He ratios range from 0.2 to 0.4 times that of the atmospheric air ratio after air correction, which fall in the range of typical crustal gas composition and are similar to those of on-shore mud volcanoes in SW Taiwan. This indicates that gases are venting actively from the seafloor in the region and may share similar gas sources to on-shore mud volcanoes. The venting gases are considered to have originated from dissociation of gas hydrates and/or a deeper gas reservoir.
Keywords	Gas hydrate ; Methane venting ; Water column ; Helium ; Radon ; Geography (General) ; G1-922 ; Geology ; QE1-996.5
Language	English
Publishing date	2006-01-01T00:00:00Z
Publisher	Chinese Geoscience Union
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article ; Online: Methane Migration and Its Influence on Sulfate Reduction in the Good Weather Ridge Region, South China Sea Continental Margin Sediments

Saulwood Lin / Wei-Chi Hsieh / Yee Cheng Lim / Tsanyao Frank Yang / Char-Shine Liu Yunshuen Wang

Terrestrial, Atmospheric and Oceanic Sciences, Vol 17, Iss 4, p

2006 Volume 883

Abstract: Bacteria sulfate reduction is a major pathway for organic carbon oxidation in marine sediments. Upward diffusion of methane from gas hydrate deep in the sedimentary strata might be another important source of carbon for sulfate reducing bacteria and ... ...

Abstract	Bacteria sulfate reduction is a major pathway for organic carbon oxidation in marine sediments. Upward diffusion of methane from gas hydrate deep in the sedimentary strata might be another important source of carbon for sulfate reducing bacteria and subsequently induce higher rates of sulfate reduction in sediments. Since abundant gas may migrate upward to the surface as a result of tectonic activity occurring in the accretionary wedge, this study investigates the effect of methane migration on the sulfate reduction process in continental margin sediments offshore southwestern Taiwan. Piston and gravity core samples were taken in order to evaluate vertical and spatial variations of sulfate and methane. Pore water sulfate, sulfide, methane, sediment pyrite, and organic carbon were extracted and analyzed.
Keywords	Sulfate reduction ; Gas hydrate ; Pyrite ; Diffusion ; South China Sea ; Geography (General) ; G1-922 ; Geology ; QE1-996.5
Language	English
Publishing date	2006-01-01T00:00:00Z
Publisher	Chinese Geoscience Union
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article ; Online: Extremely High Methane Concentration in Bottom Water and Cored Sediments from Offshore Southwestern Taiwan

Pei-Chuan Chuang / Tsanyao Frank Yang / Saulwood Lin / Hsiao-Fen Lee / Tefang F. Lan / Wei-Li Hong / Char-Shine Liu / Ju-Chin Chen / Yunshuen Wang

Terrestrial, Atmospheric and Oceanic Sciences, Vol 17, Iss 4, p

2006 Volume 903

Abstract: It has been found that Bottom Simulating Reflections (BSRs), which infer the existence of potential gas hydrates underneath seafloor sediments, are widely distributed in offshore southwestern Taiwan. Fluids and gases derived from dissociation of gas ... ...

Abstract	It has been found that Bottom Simulating Reflections (BSRs), which infer the existence of potential gas hydrates underneath seafloor sediments, are widely distributed in offshore southwestern Taiwan. Fluids and gases derived from dissociation of gas hydrates, which are typically methane enriched, affect the composition of seawater and sediments near venting areas. Hence, methane concentration of seawater and sediments become useful proxies for exploration of potential gas hydrates in a given area. We systematically collected bottom waters and sedimentary core samples for dissolved and pore-space gas analyses through five cruises: ORI-697, ORI-718, ORII-1207, ORII-1230, and ORI-732 from 2003 to 2005 in this study. Some sites with extremely high methane concentrations have been found in offshore southwestern Taiwan, e.g., sites G23 of ORI-697, N8 of ORI-718, and G96 of ORI-732. The methane concentrations of cored sediments display an increasing trend with depth. Furthermore, the down-core profiles of methane and sulfate reveal very shallow depths of sulfate methane interface (SMI) at some sites in this study. It implies sulfate reduction being mainly driven by the process of anaerobic methane oxidation (AMO) in sediments; thus indicating that there is a methane-enriched venting source, which may be the product of dissociation of gas hydrates in this area.
Keywords	Methane ; Gas hydrate ; Sulfate methane interface ; Anaerobic methane oxidation ; Geography (General) ; G1-922 ; Geology ; QE1-996.5
Subject code	550
Language	English
Publishing date	2006-01-01T00:00:00Z
Publisher	Chinese Geoscience Union
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

To top

Full text online

More links

Kategorien

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED