DOI: 10.1007/s00531-014-1018-5
论文题名: Past methane release events and environmental conditions at the upper continental slope of the South China Sea: constraints by seep carbonates
作者: Han X. ; Suess E. ; Liebetrau V. ; Eisenhauer A. ; Huang Y.
刊名: International Journal of Earth Sciences
出版年: 2014
卷: 103, 期: 7 起始页码: 1873
结束页码: 1887
语种: 英语
英文关键词: Bottom water temperature reconstruction
; Methane release events
; O- and C-isotopes
; Seep carbonates
; South China Sea
; U/Th ages
Scopus关键词: bottom water
; carbon isotope
; carbonate
; continental slope
; environmental conditions
; methane
; oxygen isotope
; uranium series dating
; water temperature
; Pacific Ocean
; South China Sea
英文摘要: Authigenic carbonates and seep biota are archives of seepage history and record paleo-environmental conditions at seep sites. We obtained the timing of past methane release events at the northeastern slope of the South China Sea based on U/Th dating of seep carbonates and seep bivalve fragments from three sites located at 22°02′–22°09′N, 118°43′–118°52′E (water depths from 473 to 785 m). Also, we were able to reconstruct the paleo-bottom water temperatures by calculating the equilibrium temperature using the ages, the corresponding past δ18O of seawater (δ18Osw) and the δ18O of the selected samples formed in contact with bottom seawater with negligible deep fluid influence. A criterion consists of mineralogy, redox-sensitive trace elements and U/Th-isotope systematics is proposed to identify whether the samples were formed from pore water or have been influenced by deep fluid. Our results show that all methane release events occurred between 11.5 ± 0.2 and 144.5 ± 12.7 ka, when sea level was about 62–104 m lower than today. Enhanced methane release during low sea-level stands seems to be modulated by reduced hydrostatic pressure, increased incision of canyons and increased sediment loads. The calculated past bottom water temperature at one site (Site 3; water depth: 767–771 m) during low sea-level stands 11.5 and 65 ka ago ranges from 3.3 to 4.0 °C, i.e., 1.3 to 2.2 °C colder than at present. The reliability of δ18O of seep carbonates and bivalve shells as a proxy for bottom water temperatures is critically assessed in light of 18O-enriched fluids that might be emitted from gas hydrate and/or clay dehydration. Our approach provides for the first time an independent estimate of past bottom water temperatures of the upper continental slope of the South China Sea. © 2014, Springer-Verlag Berlin Heidelberg. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84908604752&doi=10.1007%2fs00531-014-1018-5&partnerID=40&md5=8f5eb2d6730962790b4879bec60ba24d
Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/70456
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
There are no files associated with this item.
作者单位: Key Laboratory of Submarine Geosciences & The Second Institute of Oceanography, State Oceanic Administration, Hangzhou, China; GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany; College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR, United States; Guangzhou Marine Geological Survey, Guangzhou, China
Recommended Citation:
Han X.,Suess E.,Liebetrau V.,et al. Past methane release events and environmental conditions at the upper continental slope of the South China Sea: constraints by seep carbonates[J]. International Journal of Earth Sciences,2014-01-01,103(7)