摘要
通过米仓山地区岩浆杂岩的综合调查研究，采用同源岩浆演化序列理论，首次确认了区内澄江期侵入杂岩的存在。云雾山超单元即为该期早期基性岩浆作用的产物，同位素年龄介于７７６．５～７６６．７Ｍａ之间，由四个单元组成，具富Ｔｉ，Ａｌ，Ｆｅ的特征，其ＳＩ＝４０～１５，ＤＩ＝１１～５６，σ＝１．８～３．７；稀土及微量元素特征均显示具良好的同源岩浆演化特点。原始岩浆温度８５０～１１２５℃，成岩压力约０．７１０～０．７５６ＧＰａ，ｆＯ２≥１０－１１，具幔源为主及壳幔混合源的特征，为早震旦世龙门山—米仓山大陆裂谷作用中期阶段地幔底劈上隆的产物。
According to the ivestigation and study of the magmatic complex in Micangshan area, and using the theory of the same source magma evolution, the Chengjiang period intrusive complex has been confirmed for the first time. The Yunwushan super unit is the reslut of magmatism early during the period and consists of four units. Isotopic age is 776.5 Ma to 766.7 Ma, and the petrochemical characteristics are rich in TiO 2, Al 2O 3 and (FeO), SI=40～15, DI=11～56, σ =1.8～3.7. REE and trace elements show that each unit is the result of the same source magma evolution. The temperature of original magma is between 850℃ and 1125℃. The diagenetic pressure is about 0.710 ～0.756 GPa, f O 2 ≥10 -11 , and the magma came from the mantle melting and mixed mantle and lower crust. The basic intrusive complex is the result of the mantle diapiric uprise in the middle stage of the rift faulting during the early Sinian Period.
出处
《成都理工学院学报》
CSCD
1998年第4期537-542,共6页
Journal of Chengdu University of Technology
关键词
米仓山
基性侵入杂岩
裂谷作用
澄江期
杂岩
Micangshan
basic intrusive complex
Yunwushan super unit
rift faulting
Chengjiang period
