2-5地史学-沉积古地理学.ppt

Chapter 2 Sedimentary paleogeography-4 2.1 concepts and law 2.2 sedimentary-facies indicators 2.3 sedimentary environments How to reconstruct paleoenvironments Classifications of Sed. Environments-I Fluvial sediments Braided and meandering stream Facies model of meandering stream Velocity vectors Vertical variations in point bar deposits Lateral variations in point bar deposits Braided alluvial sediments: basic vertical sequence with binary structures of coarse- and fine- grain units, but the fine is less than the coarse in thickness Meandering sediments: vertical sequence with binary structures of coarse- and fine- units Sedimentary system for river Meandering deposits,东天山，D Meandering deposits,东天山，D Meandering deposits,东天山，D1 Meandering deposits, 牙口组，K2,河南西峡丹水 Braided-stream deposits, K2, 河南西峡夏馆剖面中部 Braided-stream deposits, 克兹尔塔格组，D3,新疆阿克苏 Floodplain sed.with plant-roots Marsh sed. on floodplain with ginkgoes etc. What is the characteristics of fluvial facies？ Meandering sediments: vertical sequence with binary structures of coarse- and fine- units Glacial sediments Glacial types tillite Glacial physiography, 哈希勒根达坂, Tianshan, 1992 Zoophycos+dropstoneWestley Park Sst Member,Brought FmBlack HeadSydney Basin Tillite, South Africa Summary of Glacial sediments Delta sediments Prograding delta-1 Delta deposits Stream dominated Tidedominated Wavedominated Delta classification What is the characteristics of delta facies？ Littoral neritic sediments Continental→shelf→slope→deep-sea Barrier-lagoonsystems 北戴河海滩 Tidal flat Tidal sediments Tidal sediments Shallow carbonate:Reef-systems Sanya Beach（三亚） Virginia Beach, W. Atlantic, USAsurfing Virginia Beach, W. Atlantic, USA Beach, lagoon, Entrance lakes, NSW, Australia Beach, 北戴河 Baltic Bay, Bornholm, Danmak, Sedimentary sequence deposited in the inner shelf（O1-2,Utah, USA） Littoral sandstone with trace fossilsand wedge beddings(O1-2,Utah, USA） Tempostite with graded beddings（O1-2,Utah, USA） temp