四川东部华蓥山三叠系海相碳酸盐岩对海水信息的保存性评估  

Preservative evaluation of coeval seawater information for the Triassic marine carbonate rocks in the Huaying Mountain,eastern Sichuan

作　　者：胡作维[1] 黄思静[1] 黄可可[1] 孙伟[1] 龚业超[1] 

机构地区：[1]成都理工大学油气藏地质及开发工程国家重点实验室,沉积地质研究院,四川成都610059

出　　处：《中国地质》2010年第5期1374-1382,共9页Geology in China

基　　金：国家自然科学基金项目(40839908;40672072);教育部博士点基金项目(20050616005)资助

摘　　要：海相碳酸盐成岩蚀变及其对海水信息保存程度的认识与评估在古海洋学和沉积地质学等学科领域研究中有着重要意义,尤其对于沉积地球化学和化学地层学等方面的研究是必不可少的基础工作。笔者通过对四川东部华蓥山仰天窝剖面三叠系海相碳酸盐岩样品的微观组构观察、阴极发光和微量元素等分析表明,大多数的样品保留了较好的原始沉积组构,具有极弱和弱的阴极发光强度、较低的Mn含量和较高的Sr含量,同时也具有较小的Mn/Sr值。只有6个样品被认为遭受了较大的成岩蚀变而对海水信息的保存程度较差,需要被剔除,而大多数的样品只遭受了较小的成岩蚀变作用,较好地保留了当时海水的信息,仍然在很大程度上代表了当时的海水。Diagenetic alteration and preservative evaluation of the coeval seawater information for the marine carbonate are of great significance in paleo-oceanography and sedimentology,and can especially serve as the basic work in sedimentary geochemistry and chemostratigraphy.In this paper,rock fabric observation and cathodoluminescence and trace element analysis show that most of marine carbonate rock samples from the Yangtianwo section of the Huaying Mountain in eastern Sichuan preserve original textures,show dull cathodoluminescence,and have low Mn concentrations,high Sr concentrations,and low Mn/Sr ratios,with the exception of only six samples,which are considered to have suffered from stronger diagenetic alteration,and hence could not represent the coeval seawater.Therefore,most of marine carbonate rock samples have only suffered limited diagenetic alteration,and hence contain relatively abundant original information and can represent the coeval seawater.

关 键 词：成岩蚀变 碳酸盐 海相地层 三叠系 四川东部 

分 类 号：P588.245[天文地球—岩石学]