Original component of grain size index in core sediment from southwestern slope of the South China Sea and its paleoenvironmental implication

2005 ◽  
Vol 50 (9) ◽  
pp. 896 ◽  
Author(s):  
Muhong CHEN
2012 ◽  
Vol 70 (1) ◽  
pp. 363-380 ◽  
Author(s):  
Guanqiang Cai ◽  
Li Miao ◽  
Hongjun Chen ◽  
Guihua Sun ◽  
Jiaoqi Wu ◽  
...  

2007 ◽  
Vol 68 (1) ◽  
pp. 162-172 ◽  
Author(s):  
Sébastien Boulay ◽  
Christophe Colin ◽  
Alain Trentesaux ◽  
Stéphane Clain ◽  
Zhifei Liu ◽  
...  

AbstractGrain-size analyses, coupled with end-member modelling, have been performed on the terrigenous fraction of two Leg 184 Ocean Drilling Program sites (1144 and 1146) from the South China Sea. The grain-size distributions over the last 1.8 Ma enable a new interpretation of their connections to sea-level variations and East Asian monsoon strength. Previous investigations in this area have associated grain-size variability with enhanced eolian input during glacial stages. End-member modelling downgrades the importance of this eolian contribution and indicates that the sediments can be described as a mixture of three end-members: fluvial mud inputs, shelf reworking and river mouth migration. Grain-size variations in the Pleistocene section of the cores indicate a multiple-stage evolution: (i) from 1.8 to 1.25 Ma, the downcore grain-size variations are low but show a correspondence between monsoon rainfall intensity and the fine grain-sized fluvial inputs; no link with sea-level variations is noticeable; (ii) from 1.25 to 0.9 Ma, there is an increase (decrease) in the intermediate (fine) end-member (∼ 100 kyr cycle) that is associated with the onset of a stronger summer monsoon and modest shelf reworking; (iii) from 0.9 to 0 Ma the grain-size record is dominated by global sea-level variations; each glacial stage is associated with extensive shelf reworking and conveyance of coarse particles to the basin.


2013 ◽  
Vol 70 (1) ◽  
pp. 381-381
Author(s):  
Guanqiang Cai ◽  
Li Miao ◽  
Hongjun Chen ◽  
Guihua Sun ◽  
Jiaoqi Wu ◽  
...  

2020 ◽  
Author(s):  
Jianyu Li ◽  
Andrew Tien-Shun Lin

<p>The Loshui Sandstone, a Miocene turbidite succession accumulated in the northern slope of the rifted continental margin of the South China Sea, is exposed in the Hengchun Peninsula, Taiwan. We conduct lithofacies analysis to understand the depositional processes and mechanisms of the gigantic-thick turbidite succession.</p><p>Several features can be recognized from outcrops: (1) the Loshui Sandstone is of around 1,000 m thick with turbidite units stacked vertically; (2) high net-to-gross ratio (> 0.9) with dominant fine-to-medium grained sandstones, amalgamated beds are commonly found in the very thickly-bedded turbidites; (3) thick individual turbidite beds with a nominal thickness of 70 cm, which is thicker than classical Bouma sequence; and (4) limited deep scouring surfaces and thick mud are found. Two end-member lithofacies of high-density turbidites and low-density turbidites, respectively, are identified. High-density turbidites are thicker (more than 1 m thick) and coarser in grain size (mostly medium sands) with abundant massive intervals, dewatering structures and/or climbing ripples. Low-density turbidites tend to be thinner in thickness and finer in grain size (mostly fine sands) with parallel bedding and/or normal ripples. In addition to the above two lithofacies, chaotic deposits of mass transport deposits (MTDs) are also widespread within the studied succession.</p><p>Sand-rich, vertically aggrading succession, but lack of deep-scouring surfaces and levee deposits, indicates that turbidites are laid down by unconfined turbidity currents in a sand-rich deepwater lobe. In addition, gigantic thick turbidite unit stacked continuously up to 1,000 m, implying that the lobe is confined within a rapidly subsiding basin. We interpreted that the Loshui Sandstone is vertically stacked and accumulated within a fault-bounded trough in the deepwater area of the rifted continental margin of the South China Sea.</p><p> </p>


2003 ◽  
Vol 66 (3) ◽  
pp. 226-242 ◽  
Author(s):  
Martin G. Wiesner ◽  
Andreas Wetzel ◽  
Sandra G. Catane ◽  
Eddie L. Listanco ◽  
Hannah T. Mirabueno

2005 ◽  
Vol 67 (5) ◽  
pp. 490-495 ◽  
Author(s):  
Martin G. Wiesner ◽  
Andreas Wetzel ◽  
Sandra G. Catane ◽  
Eddie L. Listanco ◽  
Hannah T. Mirabueno

2021 ◽  
Vol 9 ◽  
Author(s):  
Xianqing Wang ◽  
Zhifeng Wan ◽  
Chongmin Chen ◽  
Sheng Chen

Marine sediments are found to record various information for example the evolution of ocean and the exchange of matter and energy between the surrounding continents and oceans. The Southwest Sub-basin is one of the most important tectonic unit in the South China Sea Basin. The geochemical information of the sediments provides potential to understand the sedimentary history of the Southwest Sub-basin of South China Sea. In this paper, the aliphatic hydrocarbon compounds in two core sediments from the Southwest sub-basin were analyzed using lipid biomarker analysis. The average concentration of the total organic carbon (TOC) and the total nitrogen (TN) for both core sediment A and sediment B are similar, falling in the range of 0.64% ± 0.18 and 0.10% ± 0.02%, respectively. The C/N ratios vary from 3.2 to 11.1, reflecting that the organic carbon was a mixture of terrestrial and marine sources with more contributions from marine sources in core sediment B than sediment A. The long-chain n-alkanes of both core sediments show an even-odd predominance, reflecting the contributions of terrestrial higher plants and short-chain n-alkanes from marine plankton or bacteria. The Pr/Ph of core sediments A and B are 0.3–0.5 and 0.2–0.4, respectively, both of which are far less than 1, indicating that the sedimentary environment was dominated by strong reduction and long-term stability. The odd-even distribution of medium-chain n-alkanes (n-C14–20) in the core sediments A and B is due to the reduction of n-fatty acids with an odd carbon dominance in a strongly reductive depositional environment.


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