Terristrial humidity increase during mid-Cretaceous : Cretaceous research in Mongolia for understanding of greenhouse Earth system

通过以下两种方法研究了蒙古东南部中白垩世Shinekhudag组和中侏罗世Eedemt组的湖相沉积：（1）通过碳同位素地层学、叶肢介生物地层学和夹生凝灰质岩石的裂变径迹年龄测定建立年代地层学;（2）通过韵律交替的页岩-白云岩的旋回性重建陆地古气候变化。基于矿物和常量元素比值的古风化作用变化和基于有机地球化学指标（TEX_）的古温度变化<86>。结果表明，这些湖相地层记录轨道控制的古气候（降水和温度）的变化在亚洲内陆的OAE间隔。

The lacustrine deposits of the mid-Cretaceous Shinekhudag Formation and middle Jurassic Eedemt Formation in southeast Mongolia are investigated through the following two strategy : (1) Establishment of chronostratigraphy by carbon-isotopic stratigraphy, conchostracans biostratigraphy, and fission-track age dating of intercalated tuffaceous rocks, and (2) Reconstruction of terrestrial paleoclimatic changes by cyclicity of the rhythmically alternating shale-dolomite, paleoweathering changes based on mineral and major elemental ratios, and paleotemperature changes based on organic geochemical proxy (TEX_<86>). The results reveal that these lacustrine strata record orbital-controlled paleoclimatic (precipitation and temperature) changes in inland Asia during the OAE intervals.