新疆阿尔泰冲乎尔地区蓝晶石-夕线石型变质带独居石CHIME二叠纪年龄及其地质意义

新疆阿尔泰冲乎尔地区蓝晶石-夕线石型变质带独居石CHIME二叠纪年龄及其地质意义

郑常青1，徐学纯1，Takenori KATO2 ，Masaki ENAMI2

1．吉林大学地球科学学院，吉林长春 130061；2．Deparment of Earth and Planetary Sciences, Nagoya University, Nagoya 464-8602, Japan

收稿日期:2007-09-20 修回日期:2007-09-20 出版日期:2007-09-20 发布日期:2007-09-20

Permian CHIME Ages of Monazites for the Kyanite-Sillimanite Type Metamorphic Belt in Chonghuer Area, Altai, Xinjiang and Their Geological Implications

ZHENG Chang-qing 1，XU Xue-chun1，KATO Takenori2，ENAMI Masaki2

1. College of Earth Sciences, Jilin University, Changchun 130061, China;2. Deparment of Earth and Planetary Sciences, Nagoya University, Nagoya 464-8602, Japan

Received:2007-09-20 Revised:2007-09-20 Online:2007-09-20 Published:2007-09-20

摘要/Abstract

摘要： 新疆冲乎尔地区的蓝晶石-夕线石型递增变质带由绿泥石-黑云母带、黑云母-石榴石带、石榴石-十字石带、十字石-蓝晶石带和夕线石带组成；递增变质作用峰期温度、压力分别为T ＝520～640℃，p =（4.5～5.8）×108 Pa；十字石-蓝晶石带和夕线石带变质岩中含有丰富的独居石，而且Th-U-Pb含量比较高，适合电子探针独居石CHIME法定年，独居石CHIME法确定的变质时代为268±10～261±20 Ma，与阿勒泰地区发育的红柱石-夕线石型（低压型）变质带形成时代（262±10～264±22 Ma）一致，说明阿尔泰造山带蓝晶石-夕线石型和红柱石-夕线石型递增变质带是同一次大规模的构造热事件的产物，时代为二叠纪中期。

Abstract: The kyanite-sillimanite type progressive metamorphic belt developed in Chonghuer area, Altai, Xinjiang,is composed of chlorite-biotite, biotite-garnet, garnet-staurolite, staurolite-kyanite and sillimanite zones. The metamorphic peak temperature and pressure of staurolite-kyanite and sillimanite zones are 560~680 ℃ and 4.4~5.8 kbar, respectively. There are abundant accessory monazites of metamorphic origin with high Th-U-Pb contents in rocks suitable for CHIME dating. The dating results show that the metamorphic age of these rocks is 268±10 Ma~ 261±20 Ma, consistent with the age of the andalusite-sillimanite type (low pressure type) metamorphism in Altai area, indicating that the kyanite-sillimanite and andalusite-sillimanite type progressive metamorphic belts were formed in the same regional tectonothermal event at Middle Permian. These ages provided the direct chronological evidence for the closure of the Paleo-Asian Ocean.

郑常青，徐学纯，Takenori KATO ，Masaki ENAMI. 新疆阿尔泰冲乎尔地区蓝晶石-夕线石型变质带独居石CHIME二叠纪年龄及其地质意义[J]. J4.

ZHENG Chang-qing 1，XU Xue-chun1，KATO Takenori2，ENAMI Masaki2. Permian CHIME Ages of Monazites for the Kyanite-Sillimanite Type Metamorphic Belt in Chonghuer Area, Altai, Xinjiang and Their Geological Implications[J]. J4.