Geochemical Characteristics and Origin of Lamprophyre in the Laichau Area, Northwestern Vietnam
详细信息
- 责任者：Yang Yizeng (Key Laboratory of Crust-Mantle Materials and Environments ; School of Earth and Space Sciences ; University of Science and Technology of China ; Hefei 230026 ; China) ; Long Qun
- 刊名：Acta Petrologica Sinica
- 出版年：2013
- 卷期：29(3)
- 关键词：煌斑岩 ; lamprophyres ; 元素地球化学 ; elements geochemistry ; 越南 ; Vietnam
- 页码：p.899-911
- 图表：illus., 3 tables, 48 refs.
- 分类号：0801
- issnNo：ISSN1000-0569
- isbnNo：CN11-1922/P
摘要
Cenozoic lamprophyre dykes exposed in the Laichau area of northwestern Vietnam hold geological significances for understanding geochemical features and evolution of deep lithosphere in the eastern part of the Tethyan orogenic belt.This study reports geochemical and Sr-Nd-Pb radiogenic isotopic composition of lamprophyre dykes from the Laichau area and discuss their petrogenesis and geological implications.Lamprophyre samples reported here are of calc-alkaline and potassic to ultra-potassic characteristics in major element contents.When compared with relating rocks in the neighbouring areas,lamprophyre dykes from the Laichau area are similar in geochemical composition with alkalic rocks in the Ailaoshan fault zone,but considerable different from volcanic rocks exposed in Hainan and southern Vietnam.The Laichau lamprophyre dykes show enriched isotopic feature of high 87Sr/86Sr ratios,low 143Nd/144Nd ratios and high radiogenic Pb isotopic composition.Evidence of trace element contents from these lamprophyre samples indicates that the magma source of the lamprophyre dykes likely suffered metasomatic processes or input of sedimentary components before partial melting of the mantle.Low 208Pb*/206Pb* ratios of lamprophyre samples imply that enrichment of the mantle source producing the Laichau lamprophyre dykes took place recently,probably related to amalgamation of the Indochina block to the Yangtze block during the Late Paleozoic to Early Mesozoic.
© 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 |