Chronology and Geochemical Characteristics of the Diabase in Xinlu Basin of Western Zhejiang and Their Significance
详细信息
- 责任者：Wang Zhengqi (Key Laboratory of Fundamental Science on Radioactive Geology and Exploration Technology ; East China Institute of Technology ; Fuzhou 344000 ; China) ; Li Ziying
- 刊名：Acta Geoscientica Sinica
- 出版年：2013
- 卷期：34(2)
- 关键词：岩石地球化学 ; lithogeochemistry ; 玄武岩 ; basalts ; 浙江 ; Zhejiang Province
- 页码：p.139-153
- 图表：illus., 6 tables, 48 refs.
- 分类号：0801
- issnNo：ISSN1006-3021
- isbnNo：CN11-3474/P
摘要
The laser microprobe 40 Ar- 39 Ar dating and detailed study of petrogeochemical characteristics of the diabase developed in Xinlu volcanic basin of western Zhejiang were carried out. The results indicate that the diabase was formed in Late Cretaceous with an age of (93±3) Ma. The diabase contains two kinds of pyroxenes (clinopyroxene and orthopyroxene), the plagioclase is labradorite, and the content of SiO 2 is between 44.00% and 50.09%, characterized by rich alkali, (5.15% on average), high K (K 2 O/Na 2 O 1.08), and low Ti (TiO 2 1.15%). Its petrological and geochemical characteristics show typical shoshonite. The shoshonite is enriched in LREE, LILE and incompatible elements, without Eu depletion, ( 87 Sr/ 86 Sr) i and ( 143 Nd/ 144 Nd) i are in the ranges of 0.70707 to 0.70870 and 0.512338 to 0.512407 respectively, Δ7/4Pb=6.0~9.2, Δ8/4Pb=48.5~68.0, and Sr=70.73~87.04, showing relatively enriched mantle signatures. It is concluded that the shoshonite in Xinlu basin is the product of lithospheric thinning combined with hotspot activity in the post-collision period of the orogenic zone. The age of shoshonite fundamentally restricts the time limit of the large-scale lithospheric thinning in Xinlu area, and suggests that dynamic processes of lithospheric thinning was affected by hotspot and the sources of crust-mantle interaction migtht have played an important role in controlling volcanics-type uranium mineralization.
© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号 地址：北京市海淀区学院路29号 邮编：100083 电话：办公室：(+86 10)66554848；文献借阅、咨询服务、科技查新：66554700 |