The Paleosol Bed and the Coal Deposition Model in Heshan Coalfield,Guangxi,China

The research about the following three aspects provides the evidences for that, the depositional environwent when Heshan Formation sediments deposited was mainly shallow, and the carbonate platform surface was relief. 1. Almost all the limestones composing Heshan coal-bearing formation are shallow-water limestones. 2. Small quantity sponge-reef rocks of Heshan coal-bearing formation are provided with the characteristics of dispersed and isolated small reefs. 3. There was a depositional break between No. N coal-seam and it's indirect carbonate floor. The discovery of the paleosol, which originated from intertidal blue alage rock underwent soil weathering and siliconizing on supratidal zone, under neath the main coal-seam, and discovery of terrestria seat earth, and the contents of some microelements in the No. N coal-seam are nearing that of plants of fresh water, demonstrates that the coal-seam in Heshan coalfield formed in the marshes arised on the abundonment carbonate tidal flat and some of them in minor region, were originated under the condition of the process of turning the closed water一body into swamps on the surface of the carbonate platform.