论文部分内容阅读
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。
In this paper, 40Ar-39Ar ages of amphiboles from the amphibole amphibolite exposed from the Rastman hills in the East Antarctica were measured. The ages of amphiboles were 1586Ma, 1011-1080Ma, 761Ma and 529-582Ma, respectively Phragmite ages 1036Ma and 554Ma, amphibole Ar-Ar isochron age 1010Ma, these isotopic ages of evidence, for the first time a complete record of the region experienced by almost all tectonic metamorphic heat events in recent years, geology at home and abroad At home, the focus of the debate over the tectono-thermal event in the region is the answer to the question of whether the 1000-a-Gleighville event of the Late Proterozoic was older than the 500-Ma Pan-African of the early Paleozoic and whether the former existed . The results of 40Ar-39Ar dating of amphibole indicate that the Raumanian hills experienced a complex multi-stage metamorphic evolutionary history, and the protoliths may have formed in the early-Mesoproterozoic and dominated by the late Proterozoic 1000 Ma Greenville event, while the 500Ma Pan-African event is a more intense metamorphic heat event later in life.