龙门山泥盆纪层序地层的碳、锶同位素效应  

CARBON AND STRONTIUM ISOTOPIC EFFECTS OF THE DEVONIAN SEQUENCE IN THE LONGMEN MOUNTAINS AREA

作　　者：郑荣才[1] 刘文均[1] 

机构地区：[1]成都理工学院

出　　处：《地质论评》1997年第3期264-272,共9页Geological Review

基　　金：国家基础性研究重大关键项目"中国古大陆及其边缘层序和海平面变化研究"的资助

摘　　要：龙门山泥盆纪具准Ⅱ级T-R旋回的层序组,与碳、锶同位素地层曲线演化总趋势所反映的海平面升降变化规律基本一致,具极好的区域性和全球性对比意义。Ⅲ级T-R旋回层序,部分与同位素地层曲线拟合;部分有特征的异常高值波峰或低值波谷。同位素效应分别与正常海平面变化和有机碳高速埋藏、缺氧水体入侵、生物生态萧条或绝灭,以及构造和火山活动等区域性或全球性事件相联系,各具不同的区域性和全球性对比意义。On the basis of a systematical comparative study of the relationships between the Devonian stratigraphic sequence and the carbon and strontium isotopic stratigraphic curves in the Longmen Mountains area, two important characteristics of the δ13C and 87Sr/86Sr isotopic effects can be recognized from the Devonian sequence evolution; (1) The quasi- Ⅱ -order T-R cycles of the or-thosequence sets composed of 3-5 similar orthosequences are in agreement with the global sea-level changes reflected by the isotopic stratigraphic curves of δ13C and 87Sr/86Sr. The T-R cycle patterns of the orthosequence sets can be correlated on a regional or global scale. (2) The I -order T-R cycles of some orthosequences are fitted in well with the isotopic curves, while some are not. In the first case, the evolution of I -order T-R cycles and isotopic curves are controlled by the global sea-level changes and may be correlated on a regional or global scale. In the second case, there are usually high-value wave, crests or low-value wave troughs in the isotopic curves, which correspond to the I -order T-R cycles. These isotopic anomalous abundances are related respectively to some special isotopic effects, such as the high-speed burial of organic carbon, periodic invasion of anoxic seawater, mass extinction or ecological bleakness, regional tectonic subsidence or volcanic eruption and other events. Most of them can be correlated regionally or globally.

关 键 词：层序地层 龙门山 泥盆纪 锶同位素 碳 同位素 

分 类 号：P597[天文地球—地球化学] P534.44[天文地球—地质学]