湿地沉积模式及其地质意义

Depositional Model and Geological Significance of Wetland

湿地是陆地和水域(湖泊、海洋)之间的过渡区域,是一类重要的沉积相。从沉积学的角度对湿地的定义进行了重新厘定和分类,将湿地分为两类,即沼泽湿地(或称沼泽)和湿原湿地(或称湿原),前者沉积为煤,后者沉积为富含植物化石的泥岩。很多研究者把暗色泥岩都归为水下还原环境(湖泊)沉积,当作潜在的生油岩,这显然是错误的,因为一些暗色泥岩可能是湿原沉积,不能形成生油岩。因此,掌握湿地的沉积模式和识别特征,正确区分湿原与湖泊沉积,对盆地生油潜力评价及湖盆演化历史认识具有重要意义。

Wetland as a transitional area between land and water area（e.g.lake,ocean） is a significant type of sedimentary facies.In this paper,the wetland is redefined and reclassified,and divided into two types from the view point of sedimentology,and divided into two types,i.e.swamp wetland（swamp in brief） and wet plain wetland（wet plain in brief）.The deposit of the former is coal,while that of the latter is mudstone with rich plant fossils.Many researchers always classified dark mudstone into underwater reduction environment（lake） sediment and regarded it as potential source rock.This is definitely incorrect.Because some dark mudstones can be wet plain sediments and can not become as source rocks.So,to know well the depositional model and recognition feature of wetland and exactly distinguish wet plain and lake deposits or sediments are of great significance for basin oil genetic potential evaluation and lake basin evolution history understandings.