摘要
祥播二叠系生物礁剖面微量元素的分布主要受控于沉积-成岩环境、生物作用、地质事件等因素。根据剖面纵向上188件光谱分析样及167件碳酸盐岩化学分析样所表现的微量元素(特别是Sr、Mn等)、 CaCo_3、MgCo_3、酸不溶物的含量分布特征,将中、上二叠统地层划分开,并且利用微量元素的含量特征反证所划微相的合理性。根据Sr、Mn及亲石元素的变化,可看出上二叠统礁岩所经受的成岩强度大于中二叠统的礁岩。前者曾在一个极浅-较浅的大气水环境中成岩。结合化学成分资料,说明上二叠统礁岩是在水体逐渐变浅的过程中形成的,是一个旋回性海退型生物礁。
The trace-element distribution in the organic reef section from Permian of Xiangbo is controlled by the factors of sedimentary-diagenetic environ-ment, biogenic agency, geologic event etc. According to the distribution fea-tures of the contents of the trace-elements (especially, Sr, Mn etc.), CaCO_3, MgCO_3 and acid-nonsoluble materials, which are shown by the spectrogra-phic analyses of 188 samples and carbonate chemical analyses of 167 samples in vertical direction of the section, the strata of the Middle and Upper Per-mian are distinguished. And the reasonableness of the divided microfacies is further proven by the content features of the trace-elements. Baced on the variations of Sr, Mn and lithophile elements, the diagenetic intensity under-gone by Upper Pernian is more stronger than that undergone by Middle Per-mian. The former formed in an environment of extremely shallow-shallower atom atmospheric water. Combining the data of the chemical composition, it is shown that the reef rock from Upper Permian of Xiangbo formed in the process of the water gradually shallowing and is an organic reef of cyclic regres-sion phase.
出处
《云南地质》
1992年第1期69-74,共6页
Yunnan Geology
