摘要
本文以安徽巢县平顶山、鬼门关剖面为例，阐述了二叠系沉积的主要岩石类型，即灰岩、硅质岩和泥质岩的岩石学特征及稀土元素组成特点；划分出七种沉积相类型，即局限台地相、开阔台地相、斜坡相、盆地相、三角洲相、浅海相和陆缘泻湖相；识别出七个Ⅲ级层序，其中四个为Ⅰ型层序，三个为Ⅱ型层序。对栖霞组灰岩的地球化学测试数据进行了统计分析，总结了海侵体系域、高水位体系域的氧碳同位素、稀土元素和微量元素组成的差异，并认为造成差异的原因是海平面升降变化对氧、碳同位素。
Permian in Lower Yangtze Region is a typical sequence of mixed carbonate, chert and terrigenous clastics. Taking the Permian profiles in Chaoxian, Anhui as examples, the authors discuss its petrological and REE distribution characteristics. Seven sedimentary facies are divided, namely: restricted platform, open platform, continental slope, basin, delta, neritic and continental marginal lagoon facies. The Permian can be divided into seven third order sequences. Four of them are type I sequences, other three are type Ⅱ sequences. Then the authors elaborate geochemical characteristics of these sequences. With the rising of sea level, δ 13 C is gradually increased and δ 18 O decreased. When sealevel changed, the highstand systems tract (HST) and the trangresivestand systems tract (TST) have different REE compositions. The total REE of TST is greater than that of HST. The trace element distribution characteristics in TST is different from that of HST. Based on above work, the authors conclude that geochemical parameters such as O and C isotopes, REE and trace elements are helpful to sequence analysis.
出处
《高校地质学报》
CAS
CSCD
1996年第3期348-356,共9页
Geological Journal of China Universities
基金
中国博士后基金
杭州石油地质研究所资助
关键词
下扬子区
二叠系
层序地层
地球化学特征
Lower Yangtze Region, Permian, sequence stratigraphy, geochemical characteristics.
