浅覆盖区陆相盆地高频层序划分与岩石化学的对比——以大兴安岭北段上黑龙江盆地绣峰组为例

利用岩石化学中各种氧化物及相关比值在陆相盆地沉积作用中的不同表现性质, 讨论了上黑龙江盆地绣峰组Ⅳ级层序形成的气候、水体、沉积体系及基准面变化特征.绣峰组Ⅳ级层序自下部向中部Fe₂O₃、Fe3+/Fe2+、K₂O、Na₂O等值逐渐减小; MnO、FeO、MgO、LOS等含量逐渐增高; 层序中部向上部Fe₂O₃、K₂O、Na₂O等值逐渐增大, MnO、FeO等含量逐渐减少, 显示了绣峰组Ⅳ级层序在气候旋回控制下由水体加深、气候潮湿向水体变浅、气候干旱演变的中期基准面对称旋回特征.这一研究成果为陆相盆地高频层序划分提供了新思路. 

Comparison of High-Frequency Sequence Division and Petrochemistry in the Continental Basin of Thin Cover Area:Example with Xiufeng Formation of Upper Heilongjiang Basin in North Daxing'anling

Use different expressions of the various oxides and relevant ratio of lithochemistry in continental basin, this paper discusses the forming climate, water body, depositional system and base level characteristics of level Ⅳ sequence in Xiufeng Formation of upper Heilongjiang basin. Fe₂O₃, Fe3+/Fe2+, K₂O, Na₂O, etc. decreased gradually from bottom to middle in level Ⅳ sequence of Xiufeng Formation; MnO, FeO, MgO, LOS, etc. increased gradually; from middle to top, Fe₂O₃, K₂O, Na₂O, etc. increased gradually, MnO, FeO, etc. decreased. The symmetrical cycle characteristics show that the base level of the middle period is from a deep water body and a damp climate, changing to a shallow water body and dry climate in level Ⅳ sequence of Xiufeng Formation. This study provides a new thought for high frequency sequence division of continental basin.