Origin and composition of hydrothermal fluids related to the formation of granite-related Sn-W deposits in SW England.

英格兰西南部的铜锡钨矿床与华力西花岗岩浆作用有关，并伴生云英岩和热液脉。电气石是这一系列事件的完美记录者，因为它在所有这些阶段都大量存在，而且它的结构中含有(除许多其他微量元素外)铜、锡和钨。在第一个资助期内，根据电气石的结构背景和矿石矿物(主要是锡石)的存在或不存在，确定了各代电气石的主要、次要和微量元素组成。为了完成这个项目，我们的目标是详细地描述所涉及的流体类型的性质，以便了解哪些流体携带了成矿元素。因此，预计将完成显微测温研究(加热-冷冻阶段)，并通过LA-ICPMS手段确定最合适和表征良好的样品中选定的流体包裹体的主要、次要和微量元素组成。为了阐明重要元素的来源，确定流体类型本身的来源将是至关重要的，这将通过分析电气石和石英的氧同位素来完成。有了这个全面的数据集，我们将能够开发出英格兰西南部科努比安岩基不同岩浆-热液系统的详细成因模型，并可能应用于与花岗岩有关的锡沃矿。

Cu-Sn-W deposits of SW England are related to Variscan granitic magmatism and accompanying greisen and hydrothermal veins. Tourmaline is a perfect recorder of this sequence of events as it is present during all these stages in abundant quantities and it incorporates (besides many other trace elements) Cu, Sn and W into its structure. During the first funding period, the major, minor and trace element composition of the various tourmaline generations was determined in relation to their textural context and the presence or absence of ore minerals (mainly cassiterite). To finish up this project we aim to characterize the nature of the involved fluid types in detail in order to understand, which fluid carried the ore-forming elements. It is therefore anticipated to complete the microthermometric studies (heating-freezing stage) and to determine the major, minor and trace element composition of selected fluid inclusions of the best-suited and well-characterized samples by means of LA-ICP-MS. To illuminate the origin of the important elements it will be of fundamental importance to identify the origin of the fluid types themselves, which will be accomplished by analyzing O- and H-isotopes for tourmaline and O isotopes of quartz. With this comprehensive dataset, we will be able to develop a detailed model for the genesis of the diverse magmatic to hydrothermal systems of the Cornubian batholith in SW England, with possible application to granite-related Sn-Wo deposits in general.