Fluorite (U-Th)/He geochronology: methodical development and case studies

萤石 (U-Th)/He 地质年代学：方法开发和案例研究

• 批准号: 183931056
• 负责人: Dr. István Dunkl
• 金额: --
• 依托单位: Abteilung Sedimentologie und Umweltgeologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2011
• 资助国家: 德国
• 起止时间: 2010-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/183931056?language=en
• 关键词: Fluorite; Th; He; geochronology; methodical

Fluorite is a widespread mineral species that forms in highly variable geological environments ranging from pegmatitic to diagenetic conditions. The few data available suggest that this mineral is suitable for (U-Th)/He geochronology although its closure temperature is not known yet. We plan to study the diffusion of helium in fluorite and its possible dependence on crystallographic parameters on various natural fluorites in order to determine experimentally the closure temperature of the fluorite-He thermochronometer. Additionally two types of natural case studies will be investigated: (i) fluorite occurrences where the fluorite-He ages could be related to the thermal history of the region as constrained by several independent thermochronometers. This allows for deriving an empirical closure temperature. (ii) Fluorite-He, Sm/Nd and geochemical data of carbonate-hosted fluorite (mostly diagenetic or fluorite-bearing Pb-Zn ore deposits) will be used to constrain the genetic conditions and derive thermochronological data of such occurrences. The development of the method has strong potential with respect to thermochronology of apatite and zircon-free lithologies such as carbonate nappes of fold-and-thrust belts.

氟矿是一种广泛的矿物质物种，在高度可变的地质环境中形成，范围从山地肌到成岩条件。可用的少数数据表明，尽管尚不清楚其封闭温度，但该矿物质适用于（u-th）/MESERONOLOGY。我们计划研究氦在荧光岩中的扩散及其对各种天然荧光岩上晶体学参数的可能依赖性，以便通过实验确定氟含量的荧光素体温度 - 他的热化学计。另外，将研究两种类型的自然案例研究：（i）氟矿的发生，其中氟中的年龄可能与该区域的热史有关，这受到了几个独立的热化学计的约束。这允许得出经验闭合温度。 （ii）将使用荧光岩，SM/ND和地球化学数据（大多数是成岩或含氟含石的PB-ZN矿床）来限制此类事件的遗传条件并得出热量数据。该方法的开发在磷灰石和无锆石岩性的热量学方面具有强大的潜力，例如褶皱带的碳酸盐nap缩。

项目成果

Variable helium diffusion characteristics in fluorite

萤石中不同的氦扩散特性

• DOI: 10.1016/j.gca.2016.05.029
• 发表时间: 2016
• 期刊: Geochimica et Cosmochimica Acta
• 影响因子: 5
• 作者: Stockli;Wiedenbeck;von Eynatten
• 通讯作者: von Eynatten

The Age of the Latest Thermal Overprint of Tin and Polymetallic Deposits in the Erzgebirge, Germany: Constraints from Fluorite (U-Th-Sm)/He Thermochronology

• DOI: 10.2113/econgeo.110.8.2025
• 发表时间: 2015-12
• 期刊: Economic Geology
• 影响因子: 5.8
• 作者: R. Wolff;I. Dunkl;U. Kempe;H. Eynatten

Superposition of burial and hydrothermal events: post‐Variscan thermal evolution of the Erzgebirge, Germany

埋藏和热液事件的叠加：德国厄尔士山脉的后瓦里斯坎热演化

• DOI: 10.1111/ter.12159
• 发表时间: 2015
• 期刊: Terra Nova
• 影响因子: 2.4
• 作者: T. von Eynatten