Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5483748 | International Journal of Coal Geology | 2017 | 18 Pages |
Abstract
In the Laoheishan Basin, both coal and “oil shale” layers are derived from land plant organic matter. This contrast the “oil shale” of this basin from oil shale/coal intercalations in fault-related basins, in which oil shale has been found to be of algal origin. The coal is sub-bituminous in rank, hydrogen-rich and oil-prone. The “oil shale” is of low-medium grade and the relatively low oil yield may relate to the abundant resinite and sporinite, because of their lower generation potential compared with alginite. Accumulation of the high-ash coal commenced in low-lying mire, drowned during frequent floodings. Subsequently high-ash, low-sulfur coal was deposited in a stable low-lying mire, under oxic conditions and limited bacterial activity. Afterwards the mire was drowned and formed a freshwater, dysoxic to oxic shallow lake, in which “oil shale” layers accumulated. Finally, the depositional environment returned to low-lying mire but probably with a brackish influence, as indicated by elevated sulfur contents in the uppermost samples. Petrography- and biomarker-based proxies indicate that gymnosperms dominated the paleovegetation of the mire, accompanied by variable amounts of herbaceous plants, such as ferns.
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Authors
Yu Song, Zhaojun Liu, Achim Bechtel, Reinhard F. Sachsenhofer, Doris GroÃ, Qingtao Meng,