Re-Os and U-Th-Pb dating of the Rochovce granite and its mineralization (Western Carpathians, Slovakia)
Re-Os and U-Th-Pb dating of the Rochovce granite and its mineralization (Western Carpathians, Slovakia)
复制标题
Rochovce 花岗岩及其矿化的 Re-Os 和 U-Th-Pb 定年（斯洛伐克西喀尔巴阡山脉）
DOI：
--
复制
发表时间：
2013
期刊：
影响因子：
--
通讯作者：
L. Hraško
中科院分区：
文献类型：
--
作者：
Milan Kohút;H. Stein;P. Uher;Aaron Aimmerman;L. Hraško
罗霍夫采花岗岩侵入体位于斯洛伐克西喀尔巴阡山脉中部两个主要构造单元（Veporic单元和Gemeric单元）之间的接触带。用锆石U-Pb和辉橄榄岩Re-Os两种独立的方法确定了该花岗岩及其钼钨矿化的白垩纪时代。研究的锆石具有典型的均匀特征，具有振荡环带和稀少的残余岩核。SHRIMP U-Pb数据提供的年龄为81.5 ± 0.7 Ma，而残留岩芯则表明最新的新元古代-埃迪卡拉纪年龄（~565 Ma）。锆石εHf（81）值为-5.2 ~+ 0.2，反映下地壳源区，而新元古代岩芯εHf（565）= + 7.4，反映地幔影响的古老前兆。两个性质截然不同的含钨钼岩样品证实了钨钼矿化与罗霍夫切花岗岩之间的成因联系。其中一个样品是来自外接触带（Ochtiná组的蚀变石英绢云母片岩）的石英-绢英岩脉，其Re-Os年龄为81.4 ± 0.3 Ma。第二类辉橄榄岩产于细粒花岗岩中，呈1-2 mm的浸染状，其年龄为81.6 ± 0.3Ma。这两个Re-Os年龄是相同的2-西格玛分析的不确定性，并建议快速折返后碰撞，造山带平行的扩展和去顶的结果。罗霍夫采花岗岩代表了白垩纪钙碱性岩浆活动的最北端，具有与阿尔卑斯-巴尔干-喀尔巴阡-迪纳里德成矿带相关的钼-钨矿化作用。
Abstract The subsurface Rochovce granite intrusion was emplaced into the contact zone between two principal tectonic units (the Veporic Unit and the Gemeric Unit) of the Central Western Carpathians (CWC), Slovakia. The Cretaceous age of this granite and its Mo-W mineralization is shown using two independent methods: U-Pb on zircon and Re-Os on molybdenite. The studied zircons have a typical homogeneous character with oscillatory zoning and scarce restite cores. SHRIMP U-Pb data provide an age of 81.5 ± 0.7 Ma, whereas restite cores suggest a latest Neoproterozoic-Ediacaran age (~565 Ma) source. Zircon εHf(81) values -5.2 to + 0.2 suggest a lower crustal source, whereas one from the Neoproterozoic core εHf(565)= + 7.4 call for the mantle influenced old precursor. Two molybdenite- bearing samples of very different character affirm a genetic relation between W-Mo mineralization and the Rochovce granite. One sample, a quartz-molybdenite vein from the exocontact (altered quartz-sericite schist of the Ochtiná Formation), provides a Re-Os age of 81.4 ± 0.3 Ma. The second molybdenite occurs as 1-2 mm disseminations in finegrained granite, and provides an age of 81.6 ± 0.3 Ma. Both Re-Os ages are identical within their 2-sigma analytical uncertainty and suggest rapid exhumation as a consequence of post-collisional, orogen-parallel extension and unroofing. The Rochovce granite represents the northernmost occurrence of Cretaceous calc-alkaline magmatism with Mo-W mineralization associated with the Alpine-Balkan-Carpathian-Dinaride metallogenic belt.