地学前缘 ›› 2011, Vol. 18 ›› Issue (2): 140-150.

• 论文 • 上一篇    下一篇

南阿尔金巴什瓦克高压/超高温麻粒岩中金红石Zr温度计及其地质意义

于胜尧，张建新，宫江华   

  1. 中国地质科学院 地质研究所，  北京 100037
  • 收稿日期:2011-01-06 修回日期:2011-01-27 出版日期:2011-03-15 发布日期:2011-04-15
  • 作者简介:于胜尧 (1981—)，男，博士研究生，构造地质学专业。E-mail：yushengyao1981@163.com
  • 基金资助:

    中国地质调查局项目(1212010918006)；国家自然科学基金项目(41072151)

Zrinrutile thermometry in HP/UHT granulite in the Bashiwake area of the South Altun and its geological implications.

  1. Institute of Geology， Chinese Academy of Geological Sciences， Beijing 100037, China
  • Received:2011-01-06 Revised:2011-01-27 Online:2011-03-15 Published:2011-04-15

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摘要：

文中对南阿尔金高压—超高压变质带巴什瓦克地区的高压麻粒岩中的金红石进行了电子探针和薄片原位LAICPMS微量元素分析。数据结果显示，运用电子探针和薄片原位LAICPMS两种实验方法测得巴什瓦克高压麻粒岩中的金红石Zr含量在误差范围内基本一致。对比研究表明，经过压力校正的Thomkins等(2007)的金红石Zr含量温度计算公式更适合本区高压麻粒岩温度的计算，而采用Zack等(2004)和Watson等(2006)的公式计算的温度分别比前人通过传统温度计获得的温度结果偏高和偏低。按照Thomkins等(2007)的金红石Zr含量温度计算公式，以压力为2 GPa计算获得，巴什瓦克地区新鲜高压麻粒岩样品中金红石Zr含量温度为890~962 ℃，被解释为代表了高压麻粒岩峰期的变质温度；而以压力为1 GPa计算得出，退变高压麻粒岩样品中金红石Zr含量温度为764~822 ℃，代表了晚期中温麻粒岩相退变质阶段的变质温度。以上结果进一步证实南阿尔金高压—超高压变质带巴什瓦克地区的高压麻粒岩经历了峰期超高温/高压麻粒岩相变质作用和晚期中温麻粒岩相退变质作用的叠加。

关键词: 南阿尔金, 巴什瓦克, 高压麻粒岩, 金红石Zr含量温度计

Abstract:

The trace element content in rutile was analyzed by both electron microprobe (EMP) and laser ablation inductively coupled plasma mass spectrometry (LAICPMS) for HP granulite in the Bashiwake area of the South Altun HPUHP metamorphic belt. Results indicate that Zr content in rutile from HP granulite measured by EMP coincides with these measured by LAICPMS within experimental error. Zrinrutile thermometry of Thomkins et al. (2007) yields temperatures that agree with previous results by traditional thermometry calibrations， and thus it is more suitable for temperature estimation for HP granulite in Bashiwake area， whereas the other two calibrations developed by Zack et al. (2004) and Watson et al. (2006) give systematically higher or lower temperatures. Calculated Zrinrutile temperatures in fresh HP granulite range from 890 ℃ to 962 ℃ at 20 GPa， representing the peak metamorphic temperature of high pressure granulite. Zrinrutile temperatures in retrogressed HP granulite yielded temperatures between 764 ℃ and 822 ℃. These results further show that HP granulites in the Bashiwake area of the South Altun HPUHP metamorphic belt experienced peak conditions at ultrahigh temperature and high pressure， followed by medium temperature granulite facies conditions related to retrogression.

Key words: South Altun, Bashiwake, HP granulite, Zrinrutile thermometry

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