事件地层单位的理论及实践——以中扬子台地震旦—寒武纪界线事件集群为例

The Theory of Event Stratigraphic Unit and Its Practicing—Take the Event Group across the Sinian-Cambrian Boundary of Middle Yangtze Platform as an Example

根据事件地层学的发展现状,首次提出了一套系统的事件地层单位,由小到大大致上为事件面、事件层、事件带、事件组合和事件集群,并界定了各事件地层单位的含义和特征。在此基础上,将该套事件地层理论应用于中扬子台地震旦—寒武系界线事件地层的研究,并划分出2个事件面即生物灭绝事件面和海泛事件面,1个事件层即粘土事件层,4个事件带即海平面下降事件带、浊流事件带以及海平面上升事件带和缺氧事件带,3个事件组合即海平面下降—浊流事件组合、外星撞击—生物灭绝事件组合和海平面上升—缺氧事件组合,共同构成了1个事件集群即震旦—寒武系界线事件集群。事件地层含油性分析表明,研究区海平面上升—缺氧事件组合是有利的烃源岩,海平面下降—浊流事件组合具有一定的储集意义。

Based on the development of event stratigraphy,this paper firstly suggests a series of event stratigraphic units which contain Event Surface,Event Bed,Event Zone,Event Association and Event Gathering and their meaning and characteristics have been determined.New event stratigraphic units are applied in the research of Event Group across the Sinian-Cambrian Boundary of Middle Yangtze Platform.The studies suggest that there are two Event Surfaces,i.e.biomass extinction and flooding Event Surfaces,one Event Bed,namely clay Event Bed,four Event Zones,i.e.sea-level dropping,turbidity,sea-level rising and anoxic Event Zone,three Event Associations,namely sea-level dropping-turbidity,extraterrestrial impacting-biomass extinction and sea-level rising-anoxic Event Association across the Boundary.They form an Event Gathering.The oil-bearing analysis of Event Strata indicates that sea-level rising-anoxic Event Association is favorable to producing oil,while the sea-level dropping-turbidity Event Association may be favorable to reserving oil and gas.