湘鄂西奥陶纪Tremadocian期三叶虫相  

Tremadocian Trilobite Biofacies in Western Hunan-Hubei

作　　者：袁文伟[1] 周志毅[1] 张俊明[1] 周志强[2] 孙晓文 周天梅 

机构地区：[1]中国科学院南京地质古生物研究所,江苏南京210008 [2]西安地质矿产研究所,陕西西安710054 [3]阿得雷德大学国家石油地质和地球物理研究中心 [4]宜昌地质矿产研究所,湖北宜昌443003

出　　处：《地层学杂志》2000年第4期275-282,共8页Journal of Stratigraphy

基　　金：国家自然科学基金! (No. 49772 0 87和 No. 49872 0 0 5 );国家基金委特殊学科人才培养基金;国家重点基础研究专项经费!(G2 0 0 0

摘　　要：分析了湘鄂西地区 5个剖面的奥陶纪 Tremadocian期三叶虫动物群 ,识别出 6个三叶虫相 ,即台地的 Asa-phellus- Dactylocephalus相、Dikelokephalinid相、Tungtzuella- Asaphopsis相、Psilocephalina 相 ,陆棚上斜坡的Metayuepingia- shumardiid相 ,陆棚下斜坡的 Olenid相 ;恢复了该地区 C.angulatus期、P.deltifer早—中期和 P.deltifer末期— Serratognatus期三个时段的古地理面貌 ,揭示了区内发生于 G.quadraplicatus期、P.deltifer末期和 Serratognatus中—后期的三次海退事件和发生于 P.deltifer早—中期和Six trilobite biofacies are recognized based on the change of composition and diversity of Tremadocian trilobite fauna from 5 sections in western Hunan Hubei. Four of them (Asaphellus Dactylocephalus , Dikelokephalinid, Tungtzuella Asaphopsis and Psilocephalina biofacies) indicate plateform environments, and the others (Metayuepingia shumardiid Biofacies and Olenid Biofacies) represent repectively upper and lower shelf slope conditions. Accordingly, palaeogeography of three time intervals, C. angulatus , early to middle P. deltifer and late P. deltifer to Serratognatus , are reconstructed. Litho and biofacies analysis suggests that 3 major falls ( G. quadraplicatus , late P. deltifer and middle to late Serratognatus ) and 2 major major rises (early to middle P. deltifer and early Serratognatus ) in sea level took place during the Tremadocian in this area. Interestingly, the eustatic curve (Fig. 12) coincides well with that as proposed by Nicoll et al . (1992) from Australia.

关 键 词：奥陶纪 Tremadocian期 三叶虫相 海平面变化 

分 类 号：Q915.642[天文地球—古生物学与地层学]