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- Title
- A biomarker study of depositional paleoenvironments and source inputs for the massive formation of Upper Cretaceous lacustrine source rocks in the Songliao Basin, China
- Related
- Palaeogeography, palaeoclimatology, palaeoecology, Vol. 385, (2013), p.137-151
- DOI
- 10.1016/j.palaeo.2012.12.007
- Publisher
- Elsevier
- Date
- 2013
- Author/Creator
- Song, Zhiguang
- Author/Creator
- Qin, Yin
- Author/Creator
- George, Simon C
- Author/Creator
- Wang, Li
- Author/Creator
- Guo, Jiangtao
- Author/Creator
- Feng, Zihui
- Description
- The abundance and composition of total organic carbon, aliphatic and aromatic hydrocarbons including biomarkers, and the δ¹³C composition of total organic matter and individual compounds in core samples of the Nenjiang Formation from the SK-1 borehole of the Songliao Basin provide information on the paleoenvironmental conditions of lacustrine sediments formed during the Upper Cretaceous. The distribution of n-alkanes, and their δ¹³C composition, and 4-methylsteranes and dinosteranes in the first member of the Nenjiang Formation (K₂n¹) indicate that the organic matter largely originated from algal organisms and is dominated by types I and II kerogen. The occurrence of gammacerane, aryl isoprenoids isorenieratane and low pristane/phytane and diasterane/sterane ratios further suggest a salinity stratified water column associated with anoxic bottom waters, as well as possible photic zone oxygen depletion conditions during major source rock deposition of the K₂n¹. The organic geochemical data also indicate significantly different depositional environments for the second member of the Nenjiang Formation (K₂n²) sediments, which are interpreted to have been deposited under a uniform salinity (non-stratified) oxic water column. Consequently, although the organic matter in the K₂n² sediments was largely derived from algal and bacterial sources, the kerogen types are dominantly IIb and III due to the oxidative degradation of organic matter, combined with a gradual increase in land-plant input. Furthermore, the occurrence and shift of two saw-toothed distribution patterns of the δ¹³C composition of C₂₉ to C₃₃ n-alkanes, with "W" and "M" patterns being isotopically heavy odd- and even-numbered alkanes, respectively, is suggestive of organic input shift or an unknown mechanism of carbon uptake or isotopic fractionation. In particular, the heavy even carbon numbered high molecular weight n-alkanes is rare and needs further investigation.
- Description
- 15 page(s)
- Subject Keyword
- 040300 Geology
- Subject Keyword
- Biomarkers
- Subject Keyword
- Carbon isotopic composition
- Subject Keyword
- Depositional environments
- Subject Keyword
- Lacustrine source rocks
- Subject Keyword
- Organic matter
- Subject Keyword
- Songliao Basin
- Subject Keyword
- Upper Cretaceous
- Resource Type
- journal article
- Organisation
- Macquarie University. Department of Earth and Planetary Sciences
- Identifier
- http://hdl.handle.net/1959.14/279234
- Identifier
- mq:29736
- Identifier
- ISSN:0031-0182
- Identifier
- mq-rm-2013001026
- Identifier
- mq_res-ext-2-s2.0-84879890666
- Language
- eng
- Reviewed
Macquarie University ResearchOnline
