北京十三陵雾迷山组微体植物群及沉积环境分析  

MICROFLORA AND SEDIMENTARY ENVIRONMENT OF THE WUMISHAN FORMATION (JIXIAN SYSTEM),MING TOMBS REGION, BEIJING

作　　者：周小平[1] 张忠英[1] 

机构地区：[1]南京大学地球科学系,南京210008

出　　处：《微体古生物学报》1991年第3期289-300,363-364,共12页Acta Micropalaeontologica Sinica

摘　　要：北京十三陵雾迷山组微体植物化石,数量丰富,类型多样,以三度空间状态保存于燧石中。这一微体植物群由球状体、椭球体和丝状体化石组成,共计27分类群,其中1新属新种(Tylophycus minglingense gen.et sp.nov.),1新组合种和1新修订种,该植物群比较接近于河北宣化庞家堡高于庄组和加拿大迪斯马尔湖区群的微体植物群,与蓟县雾迷山组微体植物群有一定差异。根据白云岩结构和构造特征以及地球化学特征(碳、氧同位素分析,CaO、MgO含量测定),雾迷山组以潮间—湖上带正常海相沉积环境为主,局部暴露水表。Abundant and well-preserved microfossils were obtained from the black stromatoliticand non-stromatolitic cherts of the ca. 1200--1300Ma old Wumishan Formation(JixianSystem) in the Ming Tombs region, Beijing. The Wumishan microflora is mostly composedof microfossils three-dimensionally preserved in the cherts. Altogether 27 groups ofmicrofossils were identified, including 23 species and 4 unnamed morphological groups ofcoccoids, ellipsoids, and filaments assigned to 18 genera, of which Tylophycus minglingensegen. et sp. nov. is formally described, Coniunctiophycus gaoyuzhuangense emended, and Archaeoellipsoides oblongum reclassified at the genus-level. Many elements of thismicroflora are morphologically similar to the 1400--1500 Ma old Gaoyuzhuang assem-blage in the Pangjiabu region of Hebei Province and to the 1200 Ma old Dismal Lakes as-semblage in Canada, but different from the 1200--1300 Ma old Wumishan assemblage inJixian County, Tianjin. The elongated microfossils (Archaeoellipsoides Horodyski etDonaldson and Bactrophycus Y. Zhang) discovered from 1200--1500 Ma old strata in va-rious parts of the world have significant potential in chronostratigraphic correlation. Ac-cording to the sedimentary structures and geochemical features (δ^(18)O, δ^(13)C, andChO/ MgO values) of the dolomites, the Wumishan Formation is interpreted as repre-senting supratidal to intertidal facies. Description of new genus and species Genus Tylophycus gen. nov. Etymology Generic name derived from ty1-, Greek, septal, and phyco-, Greek,algae. Type species Tylophycus minglingense gen. et sp. nov. Diagnosis Filaments multicellular, uniseriate, unbranched, slightly constricted or notconstricted at septa; septa uneven, sometimes arch-like, with spaces between cells. Termi-nal cells obtusely rounded. Middle cells of trichome cylindrical. Tylophycus mingingensis gen. et sp. nov. (Pl. Ⅱ, figs. 1, 6, 7) Etymology Specific name derived from Mingling, meaning 'the Ming Tombs' inChinese. Type specimens Holotype (thin section JW40204), filament

关 键 词：微体植物群 沉积环境 雾迷山组 

分 类 号：Q913.84[天文地球—古生物学与地层学]