神秘的微型隧道——贵州瓮安震旦系陡山沱组磷酸盐化化石上的黄铁矿拖曳痕  

Enigmatic Microtunnels——The Drag Marks of Pyrites on the Phosphatized Spheroidal Fossils from Sinian Doushantuo Formation at Weng'an, Guizhou Province

作　　者：刘鹏举[1] 尹崇玉[1] 

机构地区：[1]中国地质科学院地质研究所,北京100037

出　　处：《地质论评》2006年第1期11-14,i0006-i0007,共6页Geological Review

基　　金：国家自然科学基金资助项目(编号40272015);中国地质科学院开放实验室项目(编号KL05-4);中国地质调查局项目(编号1212010511607)的成果

摘　　要：贵州瓮安磷矿陡山沱组磷质岩中含有丰富的磷酸盐化球状化石,化石常为一些微型隧道所贯穿,这些微型隧道有生物成因和非生物成因解释。通过详细观察,发现隧道的末端常见一个黄铁矿颗粒,其大小与隧道宽度一致;隧道内壁发育有平行的纵纹,在化石壳面上发育的隧道底部常见呈棱角状的突起,在隧道转折处多呈尖凸的棱角状。这些隧道的成因应与黄铁矿关系密切,隧道为有机质降解产生的气体形成了足以使黄铁矿颗粒前导面胶磷矿溶解的压力、并驱使黄铁矿颗粒移动所形成的拖曳痕。Abundant phosphatized spheroidal fossils were preserved in Doushantuo Formation at Weng＇an phosphorite, Guizhou Province, southwest China. Some fossils were impenetrated by microtunnels. The microtunnels were interpreded as biologic causation by some one or non-biologic causation by some one else. On detailedly observing, it can be shown that some microtunnels are terminated with a pyrite grain. The size of pyrite grain is same as the diameter of microtunnel. The side walls of microtunnels are marked by parallel longitudinal striae. Some pointed protuberances can be seen on the bottom of the tunnels on the surface of fossils, the turning points of tunnels are often pointed. These microtunnels are related to pyrites, they are drag marks of pyrite grains. It proposed that degradation of organic matter in sediments may have generated gas pressure sufficient to initiate dissolution of phosphorite on the leading edge of pyrite granis, then the pyrite grains moved through dissolving phosphorite at their leading edge.

关 键 词：微型隧道 遗迹化石 黄铁矿颗粒 拖曳痕 贵州瓮安 陡山沱组 

分 类 号：Q915.2[天文地球—古生物学与地层学]