Coal and oil shale occurrence characteristic and metallogenic regularity in Yilan Basin.

Taking Yilan Basin which is a typical Cenozoic fault basin for example, the occurrence and forming conditions were studied on shale, oil shale and coal based on field section profiles and comprehensive analysis indoors. Furthermore, the genesis and metallogenic regularities of coal and oil shale were showed by studying on paleoclimte, paleoenvironment and paleotectonic conditions. Coal-bearing beds of coal co-occurring with oil shale easily formed during episodic movement of tectonic subsidence at the beginning of the basin evolution. Coal deposited in shallow lacustrine basin of the fan front, and oil shale directly deposited on the coal interval, while oil shale stable sedimentary time during lake-basin expansion. Coal formed in lake marsh, while oil shale deposited in lake marsh and lacustrine. Coal and oil shale distributions were controlled by the basin-controlling fault of Yilan Basin, and became thicker near the F1 fault. That shows gradually onlapping from the lake level with the increasing depositing range of the lake basin. Coal mainly formed at warm and damp conditions, while the climate of oil shale formation generally tended to mild and a temperature decrease based on spore and pollen analysis. It was the subtropical climate, warm and damp, and the wind was weak at the lake level when the lake of Dalianhe Formation was developing. And that climate favored the formation of deep to semi-deep lake environment which was reducing and stable and easily made for oil shale. The achievements above will shape some theoretical foundations for exploring energy basins which are rich in resources of oil and gas, shale gas and coal-bed gas. [ABSTRACT FROM AUTHOR]