| 越南西北部Phan Si Pan地区Ngoi Chi岩组的锆石U-Pb年龄和Hf同位素组成 |
| 点此下载全文 |
| 引用本文：HIEU Pham Trung (范忠孝).2015.越南西北部Phan Si Pan地区Ngoi Chi岩组的锆石U-Pb年龄和Hf同位素组成[J].地球学报,36(6):755-760. |
| DOI：10.3975/cagsb.2015.06.07 |
| 摘要点击次数: 3492 |
| 全文下载次数: 3069 |
|
| 基金项目:Vietnam National University-Ho Chi Minh City (VNU-HCM) (No. C2014-18-02) |
|
| 中文摘要:本文对越南西北部Phan Si Pan地区变质地体中的一个Ngoi Chi片麻岩进行了锆石CL内部结构分析、LA-(MC)-ICP-MS锆石U-Pb定年和Hf同位素分析。CL图象和Th/U比值特征显示该片麻岩样品中的锆石主要为岩浆锆石, 有少量窄的变质边。岩浆锆石的年龄为~2.9 Ga, 表明该样品是越南西北部Phan Si Pan地区的基底岩石。它们的εHf(t)值为–4.70±0.92, 二阶段Hf模式年龄为~3.5 Ga, 表明其为更古老的 (>3.5 Ga)冥太古代地壳物质部分熔融作用形成。变质边部锆石给出了~1.8 Ga的年龄, 表明变质作用发生在古元古代早期, Phan Si Pan地区在这一时期可能经历了一次重要的构造热事件。 |
| 中文关键词:Vietnam Phan Si Pan U-Pb锆石 Hf同位素 古老岩石 |
| |
| The Ngoi Chi Formation in the Phan Si Pan Area of Northwest Vietnam Revealed by Zircon U-Pb Age and Hf Isotope Composition |
|
|
| Abstract:This paper reports the result of an integrated study of zircon U-Pb age and Hf isotope composition for a gneiss sample (Ngoi Chi formation) from the Phan Si Pan area in northwest Vietnam. CL imaging reveals that most zircons are magmatic, with a few of them exhibiting thin metamorphic rims. The magmatic zircons gave a weighted mean U-Pb age of ~2.9 Ga, indicating the gneiss is the basement rock in the Phan Si Pan area. They have εHf(t) value of –4.70±0.92, and two-stage Hf model age of ~3.5 Ga, indicating that the gneiss was derived from partial melting of >3.5 Ga crustal rock. The metamorphic rims yielded an age of ~1.8 Ga, implying that the metamorphic event occurred in the Neoarchean era, which might have been also a major tectono-thermal event in the Phan Si Pan area. |
| keywords:Vietnam Phan Si Pan U-Pb zircon Hf isotope composition basement rock |
| 查看全文 查看/发表评论 下载PDF阅读器 |
