|
|||||
|
|
| CCSD主孔100-1100m榴辉岩中单矿物的原位微区微量元素地球化学研究 | |
| 引用本文： | 宗克清 刘勇胜[,] 柳小明 张斌辉.CCSD主孔100-1100m榴辉岩中单矿物的原位微区微量元素地球化学研究[J].岩石学报,2006,22(7):1891-1904. |
| 作者姓名： | 宗克清 刘勇胜[ ] 柳小明 张斌辉 |
| 作者单位： | 1. 中国地质大学地质过程与矿产资源国家重点实验室,武汉,430074 2. 中国地质大学地质过程与矿产资源国家重点实验室,武汉,430074;西北大学地质系大陆动力学国家重点实验室,西安,710069 3. 西北大学地质系大陆动力学国家重点实验室,西安,710069 |
| 基金项目： | 国家重点基础研究发展计划(973计划);国家自然科学基金;中国地质大学校科研和教改项目;国家重点实验室基金;中国地质大学校科研和教改项目 |
| 摘 要： | 本文通过对CCSD主孔100～1100m范围内榴辉岩中单矿物的LA-ICP-MS分析，探讨了榴辉岩中单矿物之间的微量元素分配，发现超高压变质作用中石榴石和绿辉石之间Ti和C0的分配显著受Mg控制（如DCo^Grt/Omp=3．43DMg^Grt/Omp-0．34），而REE、Sr和Y的分配则受Ca分配所控制。绿辉石中REE、Pb和Th的含量则明显受超高压副矿物磷灰石的出现与否所控制。结合岩石学特征，对角闪石和绿辉石中微量元素的研究表明角闪石主要是绿辉石退变质的产物。但退变质矿物的微量元素组成不仅受原矿物控制，而且受退变质矿物组合类型影响。绿帘石的出现会显著降低共生角闪石中LREE和Sr的含量，而多硅白云母的分解则会增加角闪石中的Rb、Ba含量。另外，退变质过程中的流体活动也会影响退变质矿物中的LREE、Sr和Pb等。结合REE在榴辉岩各主要矿物间分配系数随温度、压力的变化，我们推测部分石榴石边部MREE的富集特征可能反映榴辉岩在折返过程中经历了短时增温作用，这可能是引起苏鲁地区榴辉岩相向麻粒岩相转变叠加现象以及超高压岩石经历部分熔融作用的重要原因。此外，榴辉岩中金红石Nb和Ta组成的高度不均一性为金红石形成于超高压变质阶段富Ti磁铁矿相变作用的成因机制提供了佐证。 |
| 关 键 词： | CCSD主孔 榴辉岩 原位微量元素组成 元素分配 |
| 文章编号： | 1000-0569/2006/022(07)-1891-04 |
| 收稿时间： | 04 10 2006 12:00AM |
| 修稿时间： | 06 22 2006 12:00AM |
In situ trace element geochemistry of single minerals in eclogites from the CCSD main hole (100-1100m). |
|
| ZONG KeQing,LIU YongSheng,LIU XiaoMing,ZHANG BinHui.In situ trace element geochemistry of single minerals in eclogites from the CCSD main hole (100-1100m).[J].Acta Petrologica Sinica,2006,22(7):1891-1904. | |
| Authors: | ZONG KeQing LIU YongSheng LIU XiaoMing ZHANG BinHui |
| Abstract: | In situ trace element compositions of single minerals in eclogites from the CCSD main hole(100 - 1100m) were analyzed using LA-ICP-MS. Trace element partitioning between garnet and omphacite suggests that Ti and Co are controlled by Mg( for example, Dco Grt/Omp =3.43dMg Grt/Omp -0. 34), and REE, Sr and Y are controlled by Ca. Concentrations of REE, Pb and Th in omphacite are significantly controlled by presence of apatite. Petrologic and geochemical features suggest that trace element compositions of the minerals formed by retrograde metamorphism were controlled by original minerals, the mineral assemblage and fluid activity. For example, presence of epidote decreased greatly the LREE and Sr concentrations of the coexisting amphibole compared with the omphacite, parent mineral of the amphibole based on the petrologic features; and decomposition of phengite increased Rb and Ba concentrations of amphibole. MREE enrichments in the rim of garnets in several samples imply that the eclogites could suffer a shortlived heating during exhumation based on variations of partition coefficients with temperature and pressure in eclogite, as suggested by overprinting of granulite facies on eclogites and widespread partial melting of UHP rocks in the Sulu UHP terrane. On the other hand, the highly variations of Nb and Ta in rutile could provide additional evidence for the hypothesis that rutile in the eclogite was transformed from Ti-bearing magnetite during UHP metamorphism. |
| Keywords: | LA-ICP-MS |
| 本文献已被 CNKI 维普 万方数据 等数据库收录！ | |
| 点击此处可从《岩石学报》浏览原始摘要信息 | |
| 点击此处可从《岩石学报》下载免费的PDF全文 | |