渤海湾牡蛎礁平原中部兴坨剖面全新世地质环境变迁  

Holocene geo-environmental changes at the Xingtuo sectionin the central part of the Oyster Reef plain, Bohai Bay

作　　者：李建芬[1] 王宏[1] 李凤林[1] 张金起[1] 张玉发[1] 王云生[1] 

机构地区：[1]中国地质调查局天津地质矿产研究所,天津300170

出　　处：《地质通报》2004年第2期169-176,共8页Geological Bulletin of China

基　　金：中国地质调查局国土资源调查项目(199614;70201201005);国际地质对比计划IGCP-475项目联合资助

摘　　要：渤海湾牡蛎礁平原中部兴坨剖面的有孔虫组合划分为5种沉积环境7个带(亚环境),从下向上依次为晚更新世陆相(VII带)、早全新世海陆过渡相(VI带:沿海低地与潮间带)、中晚全新世海相(Ⅴ带:潮下带-浅海,Ⅳ带:低潮线附近)、晚全新世海陆过渡相(Ⅲ带:开放潮间带Ⅱ带:湖)和河流泛滥相(Ⅰ带:古土壤及洪积层)。14C确定了全新世底泥炭始于9486calBP,Ⅳ带始于约4696calBP。Ⅱ带所处的湖环境,从约4000calBP直至隋唐温暖期之前,历时约2700年。隋唐暖期古土壤发育向南东减弱至逐渐消失,说明在比兴坨更靠近渤海湾的地方,湖持续的时间更长。广泛存在的湖,是牡蛎礁平原晚全新世的重要地貌景观。The foraminifera assemblages, found in the Xingtuo section in the central part of the Oyster Reef plain, Bohai Bay, may be subdivided into five sedimentary environments and seven zones (sub-environments). From the base upward, they are successively: late Pleistocene terrestrial facies (zone Ⅶ); early Holocene transitional facies (zone Ⅵ: coastal lowland and intertidal zone); middle-late Holocene marine facies (zone Ⅴ: subtidal-neritic zone, and zone Ⅳ: near the low-tide shoreline); late Holocene transitional facies (zone Ⅲ: open intertidal zone, and zone Ⅱ: lagoon), and river floodplain facies (zone Ⅰ: buried paleosol and diluvium). 14C dating shows the following: the basal muddy peaty layer of Holocene began at 9486 cal BP; zone Ⅳ started around 4696 cal BP; the lagoonal environment in which zone Ⅱ was located lasted for ～2700 years, from 4000 cal BP till before the warm period of the Sui-Tang dynasties. The paleosol that was well developed in the warm period of the Sui-Tang dynasties gradually faded away southeastward and disappeared gradually. It suggests that the lagoonal environment lasted longer in places much closer to the Bohai Bay than Xingtuo. The extensive lagoon was an important geomorphologic feature of the Oyster Reef plain during the late Holocene.

关 键 词：全新世 有孔虫群组合 放射性碳测年 潟湖 渤海湾 

分 类 号：P534.632[天文地球—第四纪地质学] X141[天文地球—古生物学与地层学]