渤海湾西北部CH19孔全新统硅藻组合、年代学与古环境  

Holocene diatom assemblages, chronology and palaeoenvironment of the borehole CH19 in the northwestern Bohai Bay, China

作　　者：商志文[1,2] 田立柱[2,3] 王宏[2] 范昌福[4] 裴艳东[2] 王福[2] 李建芬[2,3] 

机构地区：[1]中国地质科学院研究生院,北京100037 [2]中国地质调查局天津地质调查中心,天津300170 [3]中国地质大学海洋学院,北京100083 [4]中国地质科学院矿产资源研究所,北京100037

出　　处：《地质通报》2010年第5期675-681,共7页Geological Bulletin of China

基　　金：国家海洋局"908"专项<天津市海域地质地貌调查>(编号:908(TJ(06);中国地质调查局项目<环渤海地区重点地段环境地质调查及脆弱性评价>(编号:1212010540501)资助

摘　　要：对渤海湾西北部浅海区CH19孔岩心全新世沉积硅藻进行了系统研究,发现硅藻17属36种。与沉积学、年代学（OSL和AMS14C）研究相结合,将该孔自下而上划分为Ⅰ—Ⅶ7个硅藻带,显示研究区全新世以来经历了从陆到海的演化过程：约11kacalBP时,进入全新世潮上带湖沼环境（硅藻Ⅰ带）;约10kacalBP时开始了潮间带（硅藻Ⅱ带）至浅海（Ⅲ—Ⅶ带）的长期海水影响。其中,约10-7kacalBP为潮间带环境;6.77-3.47kacalBP的中全新世硅藻Ⅲ带,是受到风暴事件影响的、1.7m厚的贝壳碎屑与泥砂混杂堆积层;硅藻Ⅳ带复归正常浅海环境;Ⅴ带再次动荡;Ⅵ带水体盐度略有降低;Ⅶ带则反映了渤海湾西北部浅海区现代硅藻组合的状况。The diatoms of borehole CH19, located at the shallow sea area, northwestern Bohai Bay, have been systematically studied and, totally, 36 species in 17 genera were identified. Consequently, Ⅰ—Ⅶ diatom zones have been divided according to the characteristics of the diatom assemblages, the sediments and the OSL and AMS 14C chronological framework of the borehole as well. The diatom and chronostratigraphical results reveal that the study area was changed from the lacustrine to marine environment in the Holocene. The diatom Zone Ⅰ, indicating the beginning of the Holocene, 11ka cal BP, was the supratidal swamp environment. From 10ka cal BP, the area entered a long period of marine influencing environment, during which the zone Ⅱ, occurring around 10 to 7ka cal BP, was the intertidal zone; Zone Ⅲ indicated that a 1.7m-layer, consisting of mixture of unarticulated shells, shelly fragments, sandy and muddy sediments, was affected by storms during 6.77～3.47ka cal BP in the Middle Holocene; Zone Ⅳ returned back to the normal shallow sea environment; Zone Ⅴ was unstable again; Zone Ⅵ was characterized by decreasing salinity; finally, Zone Ⅶ indicates the modern diatom assemblage on the bottom of the shallow sea, northwestern Bohai Bay.

关 键 词：渤海湾 沉积硅藻组合 OSL和AMS14C测年 全新世 古环境 

分 类 号：P736[天文地球—海洋地质] X145[天文地球—海洋科学]