上海滨海平原全新世贝壳砂堤中介形虫的埋葬学研究  

Taphonomic characteristics of an ostracod thanatocoenosis in a Holocene chenier in Shanghai

作　　者：王雨楠 周保春[1] 温度 钱思源 颜培婧 WANG Yunan;ZHOU Baochun;WEN Du;QIAN Siyuan;YAN Peijing(Shanghai Natural History Museum(Branch of Shanghai Science&Technology Museum),Shanghai 200041,China;Shanghai University of International Business and Economics,Shanghai 201620,China;University College London,London WC1E 6BT,UK;Shanghai Jiaotong University School of Medicine,Shanghai 200240,China)

机构地区：[1]上海自然博物馆(上海科技馆分馆),上海200041 [2]上海对外经贸大学,上海201620 [3]University of College London,英国伦敦WC1E 6BT [4]上海交通大学医学院,上海200240

出　　处：《上海国土资源》2020年第3期67-71,共5页Shanghai Land & Resources

基　　金：上海市自然科学基金项目(14ZR1427600)。

摘　　要：本研究对采自上海市金山区漕泾镇的“冈身”贝壳砂沉积物(约6400年前)中的介形虫亚化石群,从埋葬学角度进行了物种生态、壳体保存状态及种群结构特征分析。贝壳砂样中介形虫壳瓣密度为52个/g,包含8属8种,它们均为现代东海潮间带—潮下带浅海底栖种。其中数量最多者依次为布氏形纯艳花介Pistocythereis bradyformis、皱新单角介Neomonoceratina crispata和长中华美花介Sinocytheridea longa。潮上带和潮下带介形虫种类的缺失,说明该贝壳砂堤只接受了来自潮间带的微体生物壳体。贝壳砂中的介形虫亚化石保存状态较好,然而其壳体表面纹饰遭受了较强磨蚀作用。对埋葬群中数量最多的布氏形纯艳花介Pistocythereis bradyformis壳体进行测量,同时对长江口岩心及东海浅海表层沉积样中的同一个种进行测量,对比了三个样品中该种的壳体壳长/壳高散点图。结果显示贝壳砂介形虫种群结构的最大特征是幼体少,推测是在潮间带—潮上带较强水动力作用下,相对脆弱的幼体壳体遭波浪破碎消失所致。Ostracod subfossils were discovered in a sample of sediment from the chenier in Caojing Town;it is on the southwestern area of the coastal plain of Shanghai,which formed^6400 y BP.The ecological characteristics,state of preservation,and population structure of the ostracods were analyzed based on their taphonomy.They had a high specimen density(52 valves/g),and there were eight distinct species among eight genera identified.These eight species,dominated by Pistocythereis bradyformis,Neomonoceratina crispata,and Sinocytheridea longa,are all intertidal inhabitants in the modern East China Sea,suggesting that neither supratidal nor subtidal micro-subfossils are preserved in the chenier.The ostracod shells are mostly translucent;however,they are severely abraded and reflect a condition in which saturated calcium carbonate solution together with repeated abrasion by waves during fossilization.The population structure of Pistocythereis bradyformis was analyzed based on the measurements of shell size and compared with those of the same species from modern and Holocene sediments in the East China Sea.The results show a remarkably high proportion of adults of this species in the chenier,suggesting that juveniles with more fragile shells were destroyed by wave action.

关 键 词：全新世 沉积地层 滨海平原 冈身 贝壳砂堤 介形虫 埋葬学 

分 类 号：P534.632[天文地球—第四纪地质学] Q915.819.6[天文地球—古生物学与地层学]