山东东营凹陷古近纪湖相藻礁群落结构及古生态特征  

Community Structure and Paleoecology of Paleogene Lacustrine Cladosiphonia Reefs in the Dongying Depression,Shandong Province,China

作　　者：李国山[1] 王永标[2] 卢宗盛[1] 廖卫[1] 侯玮伟[1] 

机构地区：[1]中国地质大学地球科学学院,湖北武汉430074 [2]中国地质大学地质过程与矿产资源国家重点实验室,湖北武汉430074

出　　处：《地球科学（中国地质大学学报）》2011年第6期1044-1052,共9页Earth Science-Journal of China University of Geosciences

基　　金：国家油气重大专项(No.2009ZX05009);国家自然科学基金(No.40730209)

摘　　要：地质历史上的生物礁主要为海相生物礁.海相生物礁中生物种类丰富,而且常常出现在正常的海洋环境中.陆相湖泊生物礁则极为少见,而且造礁生物种类单调,常常出现在特有的湖泊环境.山东东营凹陷古近纪湖相藻礁主要由绿藻门的枝管藻形成礁体的骨架,蓝细菌藻纹层起粘结作用.居礁生物种类十分单调,但数量丰富,主要包括广盐性的介形类、小型腹足类和龙介类.在湖相藻礁建造过程中,早期碳酸盐成岩作用产生的纤维状方解石十分发育,对加固枝管藻骨架起到了重要作用.同时,大量早期碳酸盐胶结物的存在表明当时湖泊水体的碳酸盐饱和度较高.藻礁发育的古近纪在世界许多地方出现蒸发岩沉积,反映藻礁总体是在气候比较干旱的时期形成的.枝管藻藻礁不但对古生态和气候具有重要的指示意义,而且对油气储集层的研究勘探也有重要价值.Most fossil reefs found so far are preserved in marine sediments with high biodiversity of reef-building organisms and recognized as implication for shallow normal marine environment.However,lacustrine reefs are relatively scarce and usually constructed by low biodiversity but high abundance of reef associated fossils,implying specialized water conditions.The frame of Paleogene lacustrine reefs in Dongying depression of Shandong Province were constructed mainly by Cladosiphonia and bound by Cyanobacteria.Reef-dwelling organisms are of great abundance though only a few species are involved,such as ostracodes,micro-gastropods and spirorbis,which belong to euryhaline organisms.Large amount of fibrous calcite cement was formed as the product of early diagenesis around the Cladosiphonia,reinforcing the solidity of reef structure.Early diagenesis cement widely formed in the reef structure suggests high saturation of lacustrine chemistry for carbonate precipitation.Paleogene is a special stage in geologic history,during which different types of evaporates were deposited all over the world.Paleogene Cladosiphonia-build reefs in Dongying depression should have been formed under arid climate conditions.Cladosiphonia-build reefs undoubtedly facilitates the understanding of the palaeoecology of ancient lacustrine and the condition of paleoclimate,and is of great importance to the study of petroleum reservoir as well.

关 键 词：生物礁 古近纪 东营凹陷 地层学 

分 类 号：P52[天文地球—古生物学与地层学] P534[天文地球—地质学]