华北地台中寒武世米级旋四层序与复合海平面变化

METER-SCALE CYCLIC SEQUENCES AND COMPOSITESEA-LEVEL CHANGES ON THE NORTH CHINAPLATFORM DURING MIDDLE CAMBRIAN TIME

笔者在对华北地区中寒武统颐滩碳酸盐建造露头层序地层学研究工作中首次识别出层序中最基本的地层单元──米级旋回层序，它是露头层序分析最基本的工作单元。本文总结概括出不同体系域内米级旋回层序类型和特征。这些米级旋四层序在塞向上叠加构成高级（五级、四级、三级）旋回层序时表现出周期性和规律性。这种不同级次的旋回层序的形成受不同动力成因引起的具不同周期和频率复合海平面变化的控制。米级旋回层序的识别与复合海平面变化的研究得出中寒武世鲕滩层序的形成经历了若干次周期性的淹没－间断－均衡堆积－加积进积事件，这为盆地充填史的恢复提供了新途径。

The basic stratigraphic units-meter-scale cyclic sequences and their types have beendistinguished in the Middle Cambrian oolitic shoal carbonate sequences in North China.The meter-scale cyclic sequences are also the basic research units of outcrop sequencestratigraphy.The present paper gives a detailed description of the meter-scale sequencetypes and features in different systems tracts. The regular stacking patterns of the cyclicsequences in vertical sections which consist of high-order (sib- 4th-and 3rd-order) cyclicsequences are controlled by the composite sea-level changes. The formation of oolitic shoalsequences have experienced several periodic events of drowning,interruption, isostatic accumulation,aggradation and progradation,thus providing a useful approach to the reconstruction of the basin filling history.