Metals in Magmas and Applications in Igneous and Environmental Geology

地球表面由一系列坚硬的移动板块组成，其中一些板块在俯冲带汇聚在一起。这些俯冲带是地球系统中物质(岩石和水)在地质时期(数百万到数十亿年)深固体地球(地壳和地幔)与海洋和大气之间流动的关键位置。这项研究计划侧重于俯冲带的三个组成部分，它们影响某些元素或金属的流动性，并最终影响它们在地表环境中的有效性，在那里它们可能形成矿石资源，或污染和影响生物圈。在接下来的五年里，我们将研究：(1)构成板块的不同岩石类型俯冲过程中硫的释放；(2)金属(如铜)在俯冲带附近的地幔深处的流动性，并向上进入地壳形成矿床；(3)活火山将有毒痕量金属(如铅或砷)排入大气。为此，我们在实验室模拟了极高压力(P)和极高温度(T)下的板块俯冲条件，并研究了这些参数如何影响某些岩石类型中硫的行为。反过来，俯冲板块释放的金属，或它们在地幔深处的行为，往往与硫的P、T和/或行为有内在联系，并有助于我们了解哪些金属是可移动的，以及它们如何被岩浆向上富集到地壳中，形成俯冲带上方的某些矿源。此外，我们还可以在实验室中模拟高温下火山岩浆中有毒痕量金属的释放，并在较低的温度下将这些金属从气相中冷凝。这些实验告诉我们，火山可能释放出哪些有毒金属物种，有多少会流失到大气中，以及它们会在多大程度上污染环境，并可能对生物圈产生潜在影响，无论是现在还是过去。

The Earth's surface is organized into a series of rigid moving plates, some of which converge into one another at subduction zones. These subduction zones are a key location in the earth system for the fluxes of mass (rock and water) between the deep solid earth (crust and mantle), and the oceans and atmosphere over geologic time (millions to billions of years). This research program focuses on three components of subduction zones that affect the mobility of certain elements or metals and ultimately their availability in the surface environment where they may form ore resources, or pollute and impact the biosphere. Over the next five years we examine: (1) the release of sulfur during the subduction of different rock types which make up the plates, (2) the mobility of metals (like Copper) deep in the mantle near subduction zones, and upward into the crust to make ore deposits, and (3) the degassing of toxic trace metals (like Lead or Arsenic) into the atmosphere by active volcanoes. To do this, we simulate the conditions of plate subduction at very high pressures (P) and temperatures (T) in the laboratory and examine how these parameters affect the behaviour of sulfur in certain rock types. In turn, the release of metals by the subducted plate, or their behaviour at depth in the mantle, is often intrinsically linked to the P, T and/or behaviour of sulfur, and helps us understand what kinds of metals are mobile and how they can be enriched upward in the crust by magmas to form certain ore resources above subduction zones. In addition, we can also simulate the release of toxic trace metals from magma in a volcano at high temperatures in the lab and condense those metals from the gas phase at cooler temperatures. These experiments inform us of what toxic metal species can emanate from volcanoes, how much can be lost to the atmosphere, and to what degree they can pollute the environment, and potentially impact the biosphere, both now and in the past.