甘肃玉门地区非海相第四系中的微体化石  

MICROFOSSILS IN NON-MARINE QUATERNARY SEDIMENTS FROM YUMEN OF GANSU PROVINCE, CHINA

作　　者：勾韵娴[1] 章炳高[1] 

机构地区：[1]中国科学院南京地质古生物研究所,南京210008

出　　处：《微体古生物学报》2013年第1期49-57,共9页Acta Micropalaeontologica Sinica

摘　　要：本文对甘肃玉门花海地区中更新世内陆盐湖相沉积物中保存完好的广盐性介形类 Eucypris mareotia ( Fischer , 1855 )和广盐性有孔虫 Ammonia beccarii ( Linné , 1758 ),以及极少量保存很差的钙质超微化石为代表的微体化石群特征进行了简述;对化石群中各门类化石的保存和埋葬状况进行了分析;探讨了有孔虫和钙质超微化石的来源;对非海相沉积物中有孔虫的变异进行了分析和研究。研究结果进一步证实,广盐性有孔虫在远离海洋的内陆盐湖环境中,在适宜的盐度条件下,有生存和繁殖的可能性。Fifteen nonmarine Quaternary samples are analyzed from the Middle Pleistocene saline-lacustrine deposits of Yumen, Gansu Province. A plentiful valves of Eucypris mareotica （Fisher, 1855） （Ostracoda） associated with a small number of Ammonia beccarii （Linné, 1758） （Foraminifera） are encountered in some of these samples, however sometimes E. rnareotica presents alone in another samples. Besides, a few nannofossils are also found in some samples. E. mareotica is a typical salt lake ostracod species, appearing from the Pleistocene to Recent, and it is exactly an euryhaline one. Its saline tolerance ranges from 5‰ to〉100‰. A. beccarii, emerging from the Miocene to Recent, is a shallow-water benthic form. It is also an euryhaline species, with the salinity from 0‰ to〉90‰. A. beccarii is widely spread in the sea and marine-continental trasitional areas, while it is also found in recent salt lakes and Quternary saline-lacustrine sediments in inland basins in China, which are located far from the sea. Both E. mareotica and A. beccarii comprise adults and a large number of juveniles. They are well preserved almost without broken and dissolved specimens. The variation, distinguished from the normal marine forms of A. beccarii, shows in the juveniles. Based on the state of the preservation, the population composition and the special variation in juveniles of A. beccarii, it is suggested that both E. mareotica and A. beccarii should be Middle Pleistocene autochthonous biocoenoses of monospecific fossil faunas in the studied area. Sohn and Kornicker （1979） proposed that some ostracods may have been widely distributed because of the circumglobal transport of eggs by high altitude winds at low temperature and pressure. Afterwards according to the discovery of the euryhaline foraminifera from late Quaternary salt lake deposits in Chaidamu Basin, Sun Zhencheng et al. （1992） suggested that air pathway is a possible route for organism transmission with neither the sea transgression nor a remnan

关 键 词：介形类 有孔虫 钙质超微化石 非海相沉积 盐湖 中更新世 玉门 甘肃 

分 类 号：Q915.2[天文地球—古生物学与地层学]