| The Eogene in Jiyang depression developed various of lacustrine shale, mudstoneand shaly carbonate rock, such as black shale, laminar shale riched in organic matter,calcite laminar shale, calcite shale, mud shale , laminar carbonate rock, and calcareous,silty, dolomitic, carbonaceous mudstone with the colour varied from gray-black topurple-red. The variety of these mudstone and shales is very complex in lacustrinehigh-frequency cycle. According to spectrum analysis and contrast with paleoclimateto high-frequency cycle, the main factor which control the sedimentation ofhigh-frequency cycle is paleoclimate caused by astronomical period. In this paper, wetake paleoclimate changes as a clue, by statistical analyzing and comparinginformation of sedimentary environment of 403 samples in 69 lacustrinehigh-frequency cycles in 17 wells, draw a conclusion that paloclimate changescontrolled the development or types of shale and mudstone by dominating ancientlake stratification and sedimentary proportion among organism, carbonate and clay,with a background of certain paleosalinity and farther distance to estuarine delta. TheJiyang depression located in paleomonsoon climate zone in the period of the sahejieformation sedimentation, the wet and hot climate made ancient lake become deeperwater, enhanced stratification, reduced primary productivity of plankton, decreasingsedimentary velocity of carbonate, increasing sedimentary velocity of clay, fortifiedreductibility on certain degree, and then would be available for development of blackshale, dark shale and oil shale; In the contrast, the cold and dry climate lead ancientlake to shallower water, subdued stratification, increaser primary productivity ofplankton, enhancive sedimentary velocity of aphanitic carbonate, decreasedsedimentary velocity of clay, and then would be available for development calciteshale, calcite laminar shale, calcite mudstone, shaly carbonate rock, even laminarcarbonate or dolomite rock.
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