Advances in Earth Science
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LI Zeng-xue, WEI Jiu-chuan,HAN Mei-lian
LI Zeng-xue, WEI Jiu-chuan,HAN Mei-lian. COAL FORMATION IN TRANSGRESSIVE EVENTS—A NEW PATTERN OF COAL ACCUMULATION[J]. Advances in Earth Science, 2001, 16(1): 120-124.
The sea level changes in the North China Paleozoic epicontinental basin were of high frequency, and the transgressive events were episodic. This kind of sea level changes controlled both the basin filling and the coal accumulation within the basin. Since the transgressive coal accumulation pattern being presented by Diessel (1992), there comes an great upsurge in the study of coal accumulation in transgressive process. Diessel’s theory originated from the marginal continent basin and not fit well to the epicontinental basin. Coal formation pattern in transgressive event differs from either the coal formation in the transgressive process or that in the transgressive system tracts. The authors hold the opinion that the “events” are the main controlling factor in the coal formation. The North China Paleozoic epicontinental basin was a dish like one with flat basement, which led to the transgressive events being episodic and of eventness and has great influence on the coal formation. The coal formation occurred in the period of the rapid transgressive events and were consequently overlaid by marine sediment. Thus the coalification occurred in a reduced environment. Coal bed presents basically a isochronous surface. There is a condensed interval between the coalbed and its overlying marine sedimentary bed. The condensed interval maybe the coal bed itself or the lower part of the marine sediments. Coal beds and their overlying marine limestone are the sedimentary combinantion.