Electron microprobe petrochronology of monazite-bearing garnet micaschists in the Oetztal-Stubai Complex (Alpeiner Valley, Stubai)
Electron microprobe petrochronology of monazite-bearing garnet micaschists in the Oetztal-Stubai Complex (Alpeiner Valley, Stubai)
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厄茨塔尔-斯图拜杂岩（Alpeiner Valley，斯图拜）中含独居石石榴石云母片岩的电子显微探针岩石年代学
DOI：
10.1007/s00015-019-00351-4
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发表时间：
2019
影响因子：
3.1
通讯作者：
Zimmermann
中科院分区：
文献类型：
--
作者：
Schulz;Krause;Zimmermann
变质岩中独居石定年是一种新兴的研究多变质地区的方法。采用电子探针法对JEOL JXA-8530F单独居石进行了Th-U-Pb定年。应用于Variscan和早阿尔卑斯变质的奥阿尔卑斯Oetztal-Stubai杂岩（OSC）。在斯图拜地区的Alpeiner Valley， Schrankogel杂岩是中央变质岩带的东部继承体。这部分变质岩与变质长岩交替存在。在4个云母片岩透镜样品中，石炭系独居石等时线年龄以335±4 Ma、320±4 Ma为主；分别为319±4 Ma和319±4 Ma。通过自动SEM-MLA（矿物解离分析）程序，计算出具有不同模态组成和不同体积岩石Ca含量的云母岩样品显示出独特的独居石微观结构。小的独居石簇表明新的结晶，并在313和304 Ma产生等时线。而等时线在350 ~ 315 Ma之间的大型独居石周围的磷灰石和allanite的电晕结构则表明在温度下降过程中发生了分解。变质长岩组合中的石榴石表现出岩心低含火石、边缘富火石的生长带。退向角闪化榴辉岩中的云母片岩和分带钙角闪岩在~ 12 kbar和~ 680°C处形成了高压角闪岩相的前变质峰，在4 kbar和640 ~ 600°C处形成了减压后变质峰。在减压过程中，P-T路径进入独居石稳定场。这标志着石炭纪的变质作用。在一个样品中，一个小种群由零星的二叠纪单一独居石年龄组成。缺少白垩纪的独居石种群。在具有石炭纪-白垩纪云母混合年龄的奥高山基底的广大地区，独居石年龄种群允许区分一个明显的二叠纪变质事件。
Monazite dating in metapelites is an emerging method to investigate polymetamorphic areas. A protocol for Th–U–Pb dating of monazite by electron microprobe was adopted for a JEOL JXA-8530F. It was applied to the Variscan and Early-Alpine metamorphic Austroalpine Oetztal-Stubai Complex (OSC). In the Alpeiner Valley in the Stubai region, the Schrankogel complex is the eastern succession of the Central Metabasite Zone. In this part, metabasites are alternating with metapelites. In 4 samples from micaschist lenses, dominantly Carboniferous monazite isochrone ages at 335 ± 4 Ma, 320 ± 4 Ma; 319 ± 4 Ma and 319 ± 4 Ma were obtained. The micaschist samples with diverse modal compositions and variable bulk rock Ca contents of calculated assay, display distinct monazite microstructures, as quantified by automated SEM-MLA (mineral liberation analysis) routines. Clusters of small monazite could indicate new crystallization and yielded isochrones at 313 and 304 Ma. In contrast, corona structures of apatite and allanite around large monazites with isochrones between 350 and 315 Ma suggest a decomposition during decreasing temperature. Garnets in metapelitic assemblages display growth zonations with low pyrope contents in the cores and pyrope-rich rims. A prograde metamorphism with high pressure amphibolite-facies peak conditions at ~ 12 kbar and ~ 680 °C, and a post Pmaxpath with decompression to 4 kbar and 640–600 °C was estimated from the micaschists and from zoned Ca-amphiboles in retrogressed amphibolitized eclogites. The P–T path entered the monazite stability field during the decompression. This signals a Carboniferous age of the metamorphism. A minor population in one sample is composed of sporadic Permian single monazite ages. A Cretaceous monazite population is lacking. In the wide parts of the Austroalpine basement with Carboniferous-to-Cretaceous mica mixing ages, monazite age populations allow to discriminate a distinct Permian metamorphic event.
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基于角闪岩岩石学的Oetztal-Stubai基底杂岩多变质作用
DOI：
--
发表时间：
2012
期刊：
影响因子：
--
作者：
F. Purtscheller;Garnet Amphibolite;Eclogite Amphibolite;Diablastic Garnet Amphibolite
通讯作者：
Diablastic Garnet Amphibolite
用于电子微探针分析的稀土元素参考样品
DOI：
--
发表时间：
1991
期刊：
影响因子：
--
作者：
E. Jarosewich;L. Boatner
通讯作者：
L. Boatner
南高山Ötztal基底高山榴辉岩相变质作用的岩石学约束
DOI：
--
发表时间：
1991
期刊：
影响因子：
--
作者：
G. Hoinkes;A. Kostner;M. Thöni
通讯作者：
M. Thöni
影响因子：
3.1
作者：
F. Finger;E. Krenn;B. Schulz;D. Harlov;D. Schiller
通讯作者：
F. Finger;E. Krenn;B. Schulz;D. Harlov;D. Schiller
喜马拉雅山西北部措莫拉里杂岩中独居石的流体诱导溶解分解：微量元素固定性的证据
影响因子：
3.5
作者：
D. Upadhyay;K. Pruseth
通讯作者：
K. Pruseth