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首页 > 中国极地考察知识库 > 成果信息库 > 已审查 东南极拉斯曼丘陵石榴斜长角闪岩中角闪石的~(40)Ar-~(39)Ar年龄及其地质意义

东南极拉斯曼丘陵石榴斜长角闪岩中角闪石的~(40)Ar-~(39)Ar年龄及其地质意义

【标题】东南极拉斯曼丘陵石榴斜长角闪岩中角闪石的~(40)Ar-~(39)Ar年龄及其地质意义

【Title】THE 40 Ar 39 Ar AGES OF HORNBLENDES IN GRT PL BEARING AMPHIBOLITE FROM THE LARSEMANN HILLS, EAST ANTARCTICA AND THEIR GEOLOGICAL IMPLICATIONS

【作者】 仝来喜; 刘小汉; 张连生; 陈海泓; 陈福坤; 王彦斌; 任留东

【Author】 Tong Laixi ; Liu Xiaohan ; Chen Haihong ; Wang Yanbin ; Ren Liudong

【期刊】极地研究

【Journal】

【期刊年份】1998

【卷】10

【期】

【关键词】 东南极; 石榴斜长角闪岩; 角闪石; ~(40)Ar-~(39)Ar年龄; 构造变质热事件

【Keywords】

【摘要】本文对东南极拉斯曼丘陵出露的石榴斜长角闪岩中的角闪石进行了40Ar-39Ar年龄测定,分别得到角闪石视年龄1586Ma、1011~1080Ma、761Ma和529~582Ma,角闪石坪年龄1036Ma和554Ma,角闪石Ar-Ar等时线年龄1010Ma,这些同位素年龄证据,首次完整地记录了该区所经历的几乎所有构造变质热事件,为近几年国内外地质学家关于该区构造变质热事件争论的焦点问题,即晚元古代的1000Ma格林维尔事件(Grenvilian)与早古生代的500Ma泛非事件(Pan-African)孰轻孰重以及前者是否存在,提供了答案。角闪石的40Ar-39Ar年龄测定结果表明,拉斯曼丘陵地区经历了复杂的多期变质演化历史,其原岩可能形成于早-中元古代,占主导地位的应该是晚元古代的1000Ma格林维尔事件,而500Ma泛非事件则是晚期较强烈的变质热事件。

【Abstract】In this paper we reported the 40 Ar 39 Ar dating results of hornblendes in Grt Pl bearing Amphibolite from the Larsemann Hills, East Antarctica. Their apparent ages respectively are 1586Ma, 1011-1080Ma, 761Ma, 529-582Ma. Their plateau ages of 1036Ma and 554Ma as well as an Ar Ar isochron age of 1010Ma have also been obtained respectively. These isotopic dating results for the first time by the Ar Ar method for hornblendes completely record almost all the structural metamorphic thermal events that this region experienced, and provide an answer to the controversial question on the structural metamorphic thermal events of this region in recent several years, namely, the late Proterozoic 1000Ma event (Grenvillian) and the early Palaeozoic 500Ma event (Pan African) which one is more important than another, as well as whether the former exists or not. The 40 Ar 39 Ar dating results of hornblendes show that the Larsemann Hills experienced a complicated poly metamorphic evolutionary history, and their protoliths probably formed in early to mid Proterozoic. The late Proterozoic 1000Ma event (Grenvillian) has been confirmed to be a predominant tectonothermal event whilst the early Palaeozoic 500Ma event (Pan African) has been confirmed just to be the last strong tectonothermal event in this region.

【基金/项目】

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