徐州地区下古生界碳酸盐岩的碳、氧同位素研究  

Researches on carbon and oxygen stable isotopes of lower Paleozoic carbonates in Xuzhou area

作　　者：桑树勋[1] 郑永飞[2] 张华[1] 徐磊[1] 范炳恒[1] 

机构地区：[1]中国矿业大学资源与地球科学学院,徐州221008 [2]中国科学技术大学地球和空间科学学院,合肥230026

出　　处：《岩石学报》2004年第3期707-716,共10页Acta Petrologica Sinica

基　　金：国家自然科学基金(49902010)

摘　　要：在已有的对徐州地区下古生界碳酸盐岩详细岩石学研究基础上,系统测试了碳酸盐岩方解石和白云石的碳、氧同位素组成特征;地球化学和岩石学研究相结合,综合提取了碳酸盐岩碳、氧同位素组成的沉积、成岩地质信息;初步探讨了同位素组成的地层变化及其意义。研究结果表明:碳酸盐岩碳同位素组成特征可以指示沉积环境及其演化,开阔陆表海、灰质障壁砂坝、局限陆表海、潮下带、潮渠、藻坪诸沉积相间碳酸盐岩的δ^(13)C值表现出规律性变化,碳同位素组成变化曲线上的显著正偏移与海侵有关;碳酸盐岩氧同位素组成对成岩环境及其演化有明显响应,淡水成岩环境、潮上成岩环境、潮间成岩环境、潮下成岩环境和埋藏成岩环境具有不同的碳酸盐岩氧同位素组成特征;徐州地区大北望寒武系剖面地层界线附近都有碳、氧同位素组成变化的特征显示,研究工作证实了徐州地区下古生界同位素地层划分的可行性。Based on the completed detailed petrographical researches on lower Plaeozoic carbonates in Xuzhou area, carbon and oxygen stable isotope composition features of calcite and dolomite were tested systematically, their stratigraphic distributions were explored, and then their genetic information was extracted synthetically by combination studies of geochemistry and petrology. The research fruits are the following: carbon isotope composition features mainly indicate depositional environments and their evolution of carbonate rocks, that is, the delta(13)C values of the carbonate rocks represent regular changes among open epicontinental sea, lime barrier, confined epicontinental sea, subtidal zone, tidal creek and algal tidalflat facies, and the noted positive deviation on the carbon isotope changing curve is related to a transgression; oxygen isotope composition of carbonate rocks obviously corresponds to diagenetic environments and their evolution, that is, fresh water, supertidal, intertidal, subtidal and buried diagenetic environments are respectively characterized by different oxygen isotope compositon of carbonate rocks. The vicinity of the stratigraphic boundary lines of Dabeiwang Cambrian section always shows carbon and oxygen isotope composition abrupt changes, and this approved the feasibility of isotopic stratigraphy division of lower Paleozoic sections in Xuzhou area.

关 键 词：碳氧同位素 沉积环境 成岩环境 碳酸盐岩 下古生界 徐州地区 

分 类 号：P597.2[天文地球—地球化学] P588.245[天文地球—地质学]