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Bacterial diversity in sediments of core MD05-2902 from the Xisha Trough,the South China Sea

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Acta Oceanologica Sinica 2014年第10期33卷 85-93页

作者： LI Tao WANG Peng State Key Laboratory of marine geology Tongji University guangzhou marine Geological survey

A sediment core MD05-2902 was collected from the deep-sea basin of the Xisha Trough. The vertical distribution and diversity of bacteria in the core was investigated through ten sub-sampling with an interval of 1 m using bacterial 16 S rRNA gene as a phylogenetic bio-marker. Eighteen phylogenetic groups were identified from 16 S rRNA gene clone libraries. The dominant bacterial groups were JS1, Planctomycetes and Chloroflexi, which accounted for 30.6%, 16.6%, and 15.6% of bacterial clones in the libraries, respectively. In order to reveal the relationship between biotic and abiotic data, a nonmetric multidimensional scaling analysis was performed. The result revealed that the δ15N, δ13C, total organic carbon and total organic nitrogen possibly influenced the bacterial community structure. This study expanded our knowledge of the biogeochemical cycling in the Xisha Trough sediment.

关键词： Xisha Trough bacterial diversity 16S rRNA gene

Transgression regression event element geochemistry records of southwestern Fujian in Late Triassic-Middle Jurassic

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Journal of Central South University 2013年第10期20卷 2819-2829页

作者：许中杰程日辉张莉王嘹亮 College of Earth Sciences Jilin University guangzhou Bureau of marine geology survey

Southwest Fujian area has experienced a large-scale transgression regression cycle in Late Triassic-Middle Jurassic and the maximum transgression has taken place in Early Jurassic. The migration and enrichment of geochemical element in the continuous fine-grained sediments in the basin recorded the paleosalinity and the paleodepth. The changes of paleosalinity and paleodepth indicate the sea(lake) level relative change in every period of Late Triassic-Middle Jurassic in southwestern Fujian. The relative change curve of sea(lake) level in southwestern Fujian is established based on the m value(m=100×w(MgO)/w(Al2 O3)) and the ratios of w(B)/w(Ga), w(Sr)/w(Ba) and w(Ca)/w(Mg). The curve indicates that level I sea-level relative change in southwestern Fujian is composed of the transgression in Late Triassic-Early Jurassic and the regression in the late period of Early Jurassic-Middle Jurassic. The level III sea-level relative change is frequent, which is composed by the lake level descent lake level rise lake level descent of Wenbin Shan formation in Late Triassic, the regression transgression regression of Lishan formation in Early Jurassic and the lake level rise lake level descent-lake level rise lake level descent of Zhangping formation in Middle Jurassic. The transgression regression cycle in southwestern Fujian is significantly controlled by the sea-level change in the north of South China Sea. The relative change curve trends of the level I sea-level in the north of South China Sea and the one in southwestern Fujian are the same. The maximum transgressions both occur in Early Jurassic. The level III sea-level curve reflects the fluctuation of a transgression and two regressions in the early period of Early Jurassic.

关键词： southwestern Fujian Early Mesozoic northern South China Sea element geochemistry sea-level change comparison

Sr Isotopes and REEs Geochemistry of Anhydrites from L Vent Black Smoker Chimney, East Pacific Rise 9oN–10oN

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Journal of Earth Science 2015年第6期26卷 920-928页

作者： Huiqiang Yao Huaiyang Zhou Xiaotong Peng Gaowen He guangzhou marine Geological survey National Key Laboratory of marine geology Tongji University guangzhou Institute of Geochemistry Chinese Academy of Sciences

High resolution sampling, for Sr isotope and REE analyses, was carried out along a transaction of L vent chimney collected from East Pacific Rise 9oN–10oN. Sr isotopes show these anhydrites are precipitated from a mixture between hydrothermal fluid and seawater. The calculated relative proportion of seawater and hydrothermal fluid shows that the mixing is heterogeneous on the transection of the L vent chimney. Anhydrites from the chimney show uniform chondrite-normalized REE pattern with enrichment of LREE and positive Eu anomaly. While normalized to the REE of end-member hydrothermal fluid, anhydrites also show uniform REE pattern but with negative Eu anomaly and enrichment of HREE. Combining previous studies on REEs of hydrothermal fluids from different hydrothermal systems and the hydrothermal fluid data from this region, we suggested that REE-anion complexing, rather than crystallography controlling, is the main factor that controls the REE partition behavior in the anhydrite during its precipitation from the mixture of hydrothermal fluid and seawater.

关键词： East Pacific Rise 9°N-10°N black smoker chimney anhydrite Sr isotope REE.

A Study on the Engineering Geological Properties of Fine-grained marine Sediments

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Science China Chemistry 1993年第5期36卷 616-629页

作者：牛作民 Laboratory of guangzhou marine Geological survey Ministry of Geology and Mineral Resources Guangzhou 510760 PRC

Through studies on the engineering geological properties of fine marine sediments, this article fully verified that the sedimentary environment is an important factor which determines the engineering geological properties of fine marine sediments. Meanwhile, these properties are controlled and affected by factors such as composition, physico-chemical nature, micro-textures, etc. of fine soils.

关键词： fine marine soil sedimentary environment engineering geology.

Geological Evidence for the Presence of the Emperor Event in China

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Acta Geologica Sinica(English Edition) 1993年第2期67卷 235-244页

作者： Ge Tongming, Fan Limin and Liu Jian guangzhou marine Geological survey, Ministry of geology and Mineral Resources of China, guangzhou guangzhou marine Geological survey Ministry of Geology and Mineral Resources of China Guangzhou

The presence of the reversals of the geomagnetic field within the Brunhes is indicated by paleomagnetic stuides on Cenozoic volcanic rocks in the Leizhou Peninsula, loess strata and Quaternary marine sediments in the Pearl River Mouth basin in China. These regional reversals occured at 0.58±0.13 Ma, 0.45 Ma and 0.47—0.48 Ma respectively according to the results of K-Ar isotopic dating and climatostratigraphic and biostratigraphic analyses. The reversals equivalent to the Emperor Event is suggested.The reversals revealed in different regions with various lithologic characters in China prove that the Emperor Event is a global reversal event rather than a geomagnetic excursion, and its confirmation will permit a precise definition of the Middle/Late Pleistocene boundary.

关键词： Brunhes polarity reversal Emperor Event

Tectonics and Sedimentary Basins of the South China Sea: Challenges and Progresses

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Journal of China University of Geosciences 2009年第1期20卷 1-12页

作者：周蒂姚伯初 Key Laboratory of Marginal Sea geology Chinese Academy of SciencesGuangzhou 510301China guangzhou marine Geological survey Guangzhou 510760 China

The special issue ＂Tectonics and Sedimentary Basins of the South China Sea＂ consists of 19 articles arranged in the order of deep structure, general tectonics, tectonic modeling, and sedimentary basins especially the deepwater sedimentary basins. These are part of the most recent contributions made by geoscientists in China mainland and Taiwan. In the preface we intend to present a general background of these studies. We review several controversial and challenging scientific problems understanding the tectonics, that are fundamental for evolution,

关键词： In SCS Tectonics and Sedimentary Basins of the South China Sea Challenges and Progresses

Formation and syn-rifting process of the Wan'an Basin, South China Sea

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Chinese Journal of Oceanology and Limnology 2013年第1期31卷 190-201页

作者：吕彩丽姚永坚吴时国董冬冬 Key Laboratory of marine geology and Environment Institute of OceanologyChinese Academy of Sciences Graduate University of Chinese Academy of Sciences guangzhou marine Geological survey

Based on seismic and drilling data, we calculated tectonic subsidence amounts and rates of the Wan'an Basin by backstripping. The genetic mechanism and syn-rifting process of the basin were analyzed in combination with the regional geological setting. The results reveal that the basin syn-rifted in the Eocene and early Miocene under the control of the dextral strike-slip Wan'an Fault Zone. The transtensional/ extentional stresses along this fault zone may be attributed to seafloor spreading of the South China Sea (SCS) in multiple episodes. Extensive basal faults and some small initial rifts in the early Paleogene can be related to southeastward extrusion and clockwise rotation of the Indochina Block. During the Oligocene, the nearly N-S directed spreading of the SCS derived the transtensional stresses in a roughly NW-SE orientation. The basin subsided rapidly in the middle and north to form two major subsidence centers. In the early Miocene, the SCS spread again in a nearly NW-SE direction, resulting in rapid subsidence in the southern basin continuous extending until the period ～16.3 Ma.

关键词： tectonic subsidence rift Wan'an Basin South China Sea (SCS)

Acoustic characteristics of cold-seep methane bubble behavior in the water column and its potential environmental impact

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Acta Oceanologica Sinica 2020年第5期39卷 133-144页

作者： Jiangong Wei Tingting Wu Xiguang Deng Zongze Yu Lifeng Wang Gas Hydrate Engineering and Technology Center Guangzhou Marine Geological SurveyGuangzhou 510075China MLR Key Laboratory of marine Mineral Resources Guangzhou Marine Geological SurveyGuangzhou 510075China

The amount of methane leaked from deep sea cold seeps is enormous and potentially affects the global warming,ocean acidification and global carbon *** is of great significance to study the methane bubble movement and dissolution process in the water column and its output to the *** bubbles produce strong acoustic impedance in water bodies,and bubble strings released from deep sea cold seeps are called"gas flares"which expressed as flame-like strong backscatter in the water *** characterized the morphology and movement of methane bubbles released into the water using multibeam water column data at two cold *** result shows that methane at site I reached 920 m water depth without passing through the top of the gas hydrate stability zone(GHSZ,850 m),while methane bubbles at site II passed through the top of the GHSZ(597 m)and entered the non-GHSZ(above 550 m).By applying two methods on the multibeam data,the bubble rising velocity in the water column at sites I and II were estimated to be 9.6 cm/s and 24 cm/s,*** velocity is positively associated with water depth which is inferred to be resulted from decrease of bubble size during methane ascending in the *** with numerical simulation,we concluded that formation of gas hydrate shells plays an important role in helping methane bubbles entering the upper water bodies,while other factors,including water depth,bubble velocity,initial kinetic energy and bubble size,also influence the bubble residence time in the water and the possibility of methane entering the *** estimate that methane gas flux at these two sites is 0.4×10~6–87.6×10~6 mol/a which is extremely small compared to the total amount of methane in the ocean body,however,methane leakage might exert significant impact on the ocean acidification considering the widespread distributed cold *** addition,although methane entering the atmosphere is not observed,further research is still needed to

关键词： gas bubble methane cold seep Nigerian Continental Margin Greenhouse effect Makran accretion wedge

Deepwater Canyons Reworked by Bottom Currents:Sedimentary Evolution and Genetic Model

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Journal of Earth Science 2012年第5期23卷 731-743页

作者：吕彩丽姚永坚龚月华吴时国李学杰 Key Laboratory of marine geology&Environment Institute of OceanologyChinese Academy of Sciences Graduate University of Chinese Academy of Sciences guangzhou marine Geological survey

Based on multi-beam bathymetric data and 2D high-resolution, multi-channel seismic prof＇des, combing ODPl148 drilling data, the morphology, internal sedimentary architecture, and evo-lution pattern of 17 deepwater canyons from the Middle Miocene to present are documented in the northern Baiyun （白云） sag （BS）, Pearl River Mouth basin （PRMB）, and northern South China Sea （SCS）. There exist six seismic architectural elements in these canyons, including basal erosive surfaces （BES）, thalweg deposits （TD）, lateral migration packages （LMP）, mass transport deposits （MTD）, can- yon margin deposits （CMD）, and drape deposits （DD）. According to the stratigraphical ages and geo-metrical features of these canyons, their formation and evolution processes are divided into three stages：（1） Middle Miocene scouring-filling, （2） Late Miocene lateral migration, and （3） Pliocene-Quaternary vertical overlay. An auto-cyclic progressive process of eroding and filling by turbidity currents results in the scouring-filling and vertical overlay; bottom currents are responsible for the remarkable asym-metry between the two flanks of canyons; and faults are inherent dynamic forces triggering these can yons. It is inferred that these canyons are caused by the double effects of turbidity and bottom currents under the control of faults as inherent dynamic forces.

关键词： deepwater canyon-channel bot-tom current turbidity current lateral migration,South China Sea.