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现代地质 ›› 2007, Vol. 21 ›› Issue (3): 462-468.

• 古生物学 • 上一篇    下一篇

藏北比如中侏罗世马里组遗迹化石的发现及其意义

王清山1,2,王根厚1,李尚林1,马伯永1,杨晓刚1   

  1. 1中国地质大学 地球科学与资源学院,北京100083;2辽河石油勘探局,辽宁 盘锦124010
  • 收稿日期:2006-07-13 修回日期:2007-03-18 出版日期:2007-03-20 发布日期:2007-03-20
  • 作者简介:王清山,男,工程师,博士研究生,1968年出生,古生物与地层学专业,主要从事古生物学与地层学的研究工作。Email:Ih_wangqs@tom.com。
  • 基金资助:

    国家自然科学基金项目(40672021)

Ichnofossils from the Middle Jurassic Mali Formation in Biru County, Northern Tibet, and Their Environmental Significance

WANG Qing-shan1,2, WANG Gen-hou1, LI Shang-lin1, MA Bo-yong1, YANG Xiao-gang1   

  1. 1School of Earth Sciences and Resources, China University of Geosciences, Beijing100083, China;
    2Liaohe Petroleum Exploration Bureau, Panjin, Liaoning124010, China
  • Received:2006-07-13 Revised:2007-03-18 Online:2007-03-20 Published:2007-03-20

摘要:

描述了藏北比如地区中侏罗统马里组的遗迹化石8属8种(其中包括1个新遗迹属和2个新遗迹种):表面光滑无饰、具有较薄管壁和密集新月形回填构造的不分枝水平潜穴Beaconites biruensis ichnosp.nov.,沿层面分布的哑铃形潜穴Bifungites cf. hanyangesis Yang,圆柱状厚管壁的分枝并构成假网状的潜穴Biruichnus maliensis ichnogen. et ichnosp. nov.,窄长的、内肢抓痕的二叶形遗迹Cruziana ichnosp.,以垂直于层面的圆管为中央放射出排列不规则且粗细变化较大细管的多分枝潜穴系统Micatuba cf. verso Chamberlain,平行或微斜交于层面的圆柱状微弯曲或弯曲的潜穴Palaeophycus ichnosp.,栖管段有规律地交替向两侧分叉呈Z字形或锯形的三维潜穴系统Treptichnus cf. bifurcus Miller,平行层面的、具有蹼状构造的简单U形潜穴Rhizocorallium ichnosp.。西藏比如地区中侏罗统马里组有大量的波状层理、透镜状层理和脉状层理等潮汐层理,发育侵蚀构造,上部紫红色含砾粗砂岩、长石砂岩发育,为滨岸相沉积。马里组的遗迹化石以浅层内生迹的爬行觅食潜穴和居住滤食性潜穴占有优势,也见有节肢动物的爬行迹和系统觅食潜穴,且产遗迹化石的层位见小型干涉波痕,为近海浅水中至低能的沉积环境。

关键词: 遗迹化石, 沉积环境, 马里组, 中侏罗统, 比如县, 西藏

Abstract:

The paper describes eight ichnospecies from the Middle Jurassic Mali Formation in Biru County, northern Tibet: Beaconites biruensis ichnosp. nov. is characterized by non-divarication aclinic burrow with slick, thinner pipe wall and crescent back-packing structure, Bifungites cf. hanyangesis Yang is characterized by dumbbell-shape burrow on bedding surface, Biruichnus maliensis ichnogen. et ichnosp. nov. is characterized by burrow with columned thick wall divarication showing reticulation, Cruziana ichnosp is long and narrow ichnofossils showing two leaf-shaped, Micatuba cf. verso Chamberlain is more divarication burrow  system formed into upright pipe with many actinomorphic and different diameters, Palaeophycus ichnosp.is crooked or slight cylindrical burrow paralleling bedding surface, Treptichnus cf. bifurcus Miller is three-dimensional burrow system showing flexuous and saw-shape, Rhizocorallium ichnosp is simple U-shaped burrow paralleling or showing small angle with bedding surface, web-shaped structure. Middle Jurassic Mali Formation from Biru County, Tibet  contains a variety of lenticular bedding, wave bedding and vein bedding which all called tidal bedding, also  can be seen erosion structure, main lithology of the upside is aubergine coarse sand and arkose which belong to littoral sedimentation. The ichnofossils from the Mali Formation have predominance of shallow repichina and pascichnia, also can be seen feeding burrow and crawling mark, besides, the position from ichnofossils can be seen small interference ripple,the makers of the trace fossils lived in the shore environment with low to middle energy.

Key words: trace fossils, sedimentary environment, Mali Formation, Middle Jurassic, Biru County, Tibet

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