Depositional Environment Analysis of Shanxi Formation in Eastern Ordos Basin

Key words: 
• Ordos Basin /
• Shanxi Formation /
• delta /
• shallowsea continental shelf

Abstract: The depositional environment was deeply analyzed in this paper by geochemical proxies, stratum and fossil distribution, and original sedimentary tectonics. The geochemical proxies in mudstone implied that tide and transgression reacted with the fresh water and mixed each other, concretely speaking, Element B implied the characteristics of longterm cycle of basic level, and Sr/Ba is a good proxy of super longterm cycle in the period of Shanxi in Eastern Ordos Basin. The sedimentary tectonics and fossil distribution indicated that the middlelevel tide has directly influenced the delta in southeastern part of the area in the early period of Shanxi, gradually the delta progradation become strong and tide evacuated to the southeastern fringe of the basin in the middle and late period. What's more, the stratum distribution and lithofacies also illuminated that the stratum in Eastern Ordos Basin and West Shanxi province belongs to the same deltasedimentary system, and the underwater dome in the east part of the area is not efficient to obstruct the flow to form the lake. Consequently, the delta in Shanxi Formation deposited in the shallowsea continental shelf.