摘要
温都尔庙群主要分布在内蒙古温都尔庙地区，该套地层是白乃庙－温都尔庙构造岩浆带的重要组成部分。长期以来，由于缺少古生物化石和可信的年龄数据，一般认为温都尔庙群属早古生代。本文对温都尔庙群变基性火山岩进行了Ｓｍ－Ｎｄ和Ｒｂ－Ｓｒ同位素研究，５件变基性火山岩全岩样品Ｓｍ－Ｎｄ和Ｒｂ－Ｓｒ等时线年龄分别为９６１±６６Ｍａ和６２４±１１０Ｍａ，并对其形成时代和成因提出了一些新看法。
The Ondor Sum Group is over the Ondor Sum area, Inner Mongolia, which is an important composition in Boin Sum - Ondor Sum tectonomagmatic belt. Being lacking in fossil and other dependable data of isotopic age, the Ondor Sum Group was recognized as early Paleozoic for a long time. This paper is a study on the SmNd, RbSr isotopic isochron of metamorphic volcanic rocks of Ondor Sum Group. The isotopic ages got form five basic volcanic rock samples of SmNd and RbSr are 961±66(2σ)Ma and 624±110Ma(2σ). The SmNd age data provides the first evidence of the Late Proterozoic rather than the early Paleozoic as was deduced before. εNd(t)=8.8 reveals that there would be a depleted mantle. Sedimentary facies analysis suggests that the series formed in a intercontinental small sea basin with volcanic materials and distal fragmenes which belongs to the Proterozoic passive volcanic continental margin. RbSr age data provides the metamorphicdeformed time which finished Proterozoic passive continental margin evolution and into the early Paleozoic active continental margin evolution.
出处
《地质科学》
CAS
CSCD
北大核心
1998年第1期25-30,共6页
Chinese Journal of Geology(Scientia Geologica Sinica)
基金
国家自然科学基金
关键词
火山岩
同位素测年
钐-钕
铷-锶
温都尔庙群
SmNd isotope, Ondor Sum Group, Middlelate Proterozoic Era, Inner Mongolia
