HYDROTHERMAL MINERALISATION OF THE TATRIC SUPERUNIT (WESTERN CARPATHIANS, SLOVAKIA): II. GEOCHRONOLOGY AND TIMING OF MINERALISATIONS IN THE NÍZKE TATRY MTS.
HYDROTHERMAL MINERALISATION OF THE TATRIC SUPERUNIT (WESTERN CARPATHIANS, SLOVAKIA): II. GEOCHRONOLOGY AND TIMING OF MINERALISATIONS IN THE NÍZKE TATRY MTS.
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DOI：
10.31577/geolcarp.71.2.2
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发表时间：
2020-04
影响因子：
1.3
通讯作者：
J. Majzlan;M. Chovan;S. Kiefer;A. Gerdes;Milan Kohút;P. Siman;P. Konečný;M. Števko;F. Finger;M. Waitzinger;A. Biroň;J. Luptáková;L. Ackerman;J. Hora
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作者：
J. Majzlan;M. Chovan;S. Kiefer;A. Gerdes;Milan Kohút;P. Siman;P. Konečný;M. Števko;F. Finger;M. Waitzinger;A. Biroň;J. Luptáková;L. Ackerman;J. Hora
尼兹克塔特拉山的矿石矿化被划分为多个矿化阶段，在这项工作中，通过激光烧蚀扇形场电感耦合等离子体质谱 (LA-SF-ICP-MS) 进行 U/Pb 分析、Re/Os、化学 Th/U/总 Pb 等时线法 (CHIME) 和 U-总 Pb 法进行了年代测定。这些样品主要来自大型 Dúbrava 矿床，还有来自 Magurka、Rišianka、Soviansko 和 Malé Železné 矿床和矿点的其他样品。另外，还考虑和讨论了大多数未发表的 Re/Os、K/Ar 和 Ar/Ar 数据。来自花岗岩伟晶岩的铀矿和来自石英细脉的辉钼矿的年龄分别为 343±1 和约 351 Ma，与母岩的年龄相当。先前发表的白钨矿阶段（330±5 Ma）黑云母的 K/Ar 数据被解释为冷却年龄，其与矿石成矿的关系尚不清楚。尽管仅在单个样本中，但毒砂-黄铁矿-金阶段的年代测定为 320±8 Ma。辉锑矿-闪锌矿-Pb-Sb-硫盐阶段样品的年龄也分散在这个日期附近，表明这些矿化是晚瓦里斯坎时期的。可以假设这个阶段是在流体循环系统的寿命期间形成的，并且后来辉锑矿和硫盐的沉淀仅仅是由于流体中锑溶解度的温度依赖性。伊利石的分散 K/Ar 数据记录了侏罗纪大陆裂谷，但似乎与任何热液阶段都没有联系。白云石-重晶石-四面体阶段形成于塔特里克基底裂谷后热弛豫过程中，年龄在156±13 Ma和128±4 Ma之间变化。石英-电气石阶段，缺乏矿石矿物，形成于白垩纪中期高山变质作用期间，分散数据平均约为 100 Ma。 Tatric 和 Veporic 复合体的后续压缩反映在稀疏的 U/Pb 碳酸盐年龄（72 Ma）和铀矿化的再活动（70 Ma）中。对石英-铜-硫化物和方铅矿-闪锌矿阶段的年龄的限制是不够的，但它们的形成可能位于白垩纪的最上层。脉状碳酸盐在 17-31 Ma 重新活动，大多数年龄集中在 24 Ma 左右，这与喀尔巴阡古近纪盆地中部下的塔特里克基底部分埋藏有关。这项工作记录了瓦里斯坎和高山热液活动的许多事件，这些事件可能与西喀尔巴阡山脉的构造热演化有关。
Ore mineralisations from the Nízke Tatry Mts., assigned to a number of mineralisation stages, were dated in this work by U/Pb analysis by laser ablation–sector field–inductively coupled plasma–mass spectrometry (LA–SF–ICP–MS), Re/Os, chemical Th/U/total Pb isochron method (CHIME), and U–total Pb methods. The samples originated mostly from the large Dúbrava deposit, with additional samples from Magurka, Rišianka, Soviansko, and Malé Železné deposits and occurrences. Additional, mostly unpublished Re/Os, K/Ar, and Ar/Ar data are also considered and discussed. Uraninite from a granite pegmatite and molybdenite from quartz veinlets gave ages of 343±1 and ≈351 Ma, respectively, comparable to the ages of the host rocks. The previously published K/Ar datum on biotite from the scheelite stage (330±5 Ma) is interpreted as a cooling age and its relation to the ore mineralisation is not clear. The arsenopyrite– pyrite–gold stage was dated, although only at a single sample, to 320±8 Ma. The ages for the samples of the stibnite– sphalerite–Pb–Sb-sulfosalts stage scatter also around this date, showing that these mineralisations are late Variscan. It could be assumed that this stage formed during the life span of a fluid circulation system and the later precipitation of stibnite and sulfosalts is simply owing to the temperature dependence of Sb solubility in the fluids. Scattered K/Ar data on illite document the Jurassic continental rifting but seem to be linked to none of the hydrothermal stages. The dolomite– baryte–tetrahedrite stage formed during the post-rift thermal relaxation of the Tatric basement, with ages varying between 156±13 and 128±4 Ma. The quartz–tourmaline stage, devoid of ore minerals, formed during the mid-Cretaceous Alpine metamorphism, with the scattered data averaging to ≈100 Ma. The following compression of the Tatric and Veporic complexes is reflected in sparse U/Pb carbonate ages (72 Ma) and remobilisation of uranium mineralisation (70 Ma). The constraints on the age of the quartz–Cu-sulfide and galena–sphalerite stages are insufficient but their formation could be perhaps placed into uppermost Cretaceous. The vein carbonates were remobilised at 17–31 Ma, with most ages clustering around 24 Ma, related to the burial of parts of the Tatric basement under the Central Carpathian Paleogene Basin. This work documents many episodes of Variscan and Alpine hydrothermal activity that can be linked to the tectonothermal evolution of the Western Carpathians.