Collaborative Research: PGE and Pb Systematics in Altered Abyssal Peridotites: Integrating Experiments with Natural Samples

合作研究：蚀变深渊橄榄岩中的 PGE 和 Pb 系统学：将实验与自然样品相结合

基本信息

批准号：
1347970
负责人：
Dionysios Foustoukos
金额：
$ 15.45万
依托单位：
Carnegie Institution of Washington
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2014
资助国家：
美国
起止时间：
2014-04-01 至 2017-03-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1347970&HistoricalAwards=false
关键词：
Collaborative Research PGE Pb Systematics

项目摘要

The proposed work will test the hypothesis that changes in sulfide and metal alloy mineralogy during peridotite alteration will mobilize and fractionate the PGE, Re and Pb relative to their primary magmatic concentrations. Hydrothermal experiments will constrain the solubility of PGE, Re, Pb in mantle Ni-Fe-Ru-Re bearing sulfides and metal alloys as function of temperature and redox conditions, and evaluate PGE alloy exsolution and PGE-Re fractionation under low sulfur fugacity. The natural sample part of the study will constrain the distribution and fractionation of PGE, Re, Pb in sulfides, alloys and bulk rocks from well characterized abyssal peridotites, as function of redox, alteration, sulfide mineralization and primary composition (fertile versus depleted). Through integration of the experimental and natural sample data this work will constrain the fate of PGE, Re, Pb upon recycling of altered oceanic lithosphere and whether altered peridotites can develop, over time, highly heterogeneous 187Os/188Os and 186Os/188Os ratios between refractory (metal alloys) or mobile (sulfide) reservoirs. This project is a collaborative effort between 2 US institutions, and will promote transfer of technology and expertise on novel analytical techniques to a newly established geochemical facility at USC. Researchers will share a suite of state-of-the art instrumentation including FIB-SEM, FE-EMPA, FE-SEM, LA-ICPMS and synchrotron radiation micro-X-Ray fluorescence. All the data collected will be submitted to the PetDB and IEDA, and will be available to the public through a CIW-hosted data repository. A graduate student from USC will participate towards completion of his PhD studies.Altered mantle rocks exposed at the seafloor (called "serpentinized abyssal peridotites") contain Ni-bearing metal phases associated with secondary plantinum-group element (PGE) sulfur-bearing minerals (sulfides) and PGE metal nuggets. PGEs have unique physical and chemical properties that are critical to many technological applications. Thus, they are often regarded as strategic metals in a wide range of industries including aerospace and fuel cell technology. The proposed research will significantly advance the currently limited understanding of the effects of high-temperature seawater alteration on the distribution of plantinum-group element sulfides hosted in abyssal peridotites. Moreover, abyssal peridotites provide an important record for understanding the composition and evolution of Earth?s mantle now and in the past. The proposed work is a collaborative experimental and natural sample investigation. Experimental data will define the thermodynamic properties of PGE minerals at conditions relevant to modern deep-sea volcanoes and assess critical details of PGE solubility mechanisms in Fe-Ni-Ru-Re sulfides/alloys at elevated temperature/-pressure conditions. The combined experimental results and natural sample data will lead to a fundamental new understanding on the effects of seawater alteration on the siderophile and chalcophile composition of altered peridotite and its effect on the Os and Pb isotope heterogeneity in the Earth?s mantle.

拟议的工作将检验以下假设：橄榄石改变期间硫化物和金属合金矿物学的变化将动员和分馏PGE，RE和PB相对于其主要岩浆浓度。 Hydrothermal experiments will constrain the solubility of PGE, Re, Pb in mantle Ni-Fe-Ru-Re bearing sulfides and metal alloys as function of temperature and redox conditions, and evaluate PGE alloy exsolution and PGE-Re fractionation under low sulfur fugacity.研究的自然样品部分将限制硫化物，合金和散装岩石中PGE，RE，PB的分布和分馏，这些岩石表征良好，作为氧化还原，改变，硫化物矿物质和原发性成分的功能（生育与枯竭）。通过整合实验和自然样品数据，这项工作将限制PGE，RE，PB的命运，因为回收了变化的海洋岩石圈，以及随着时间的推移，橄榄岩的改变是否可以发展出高度异质性的187OS/188OS和186OS/188OS，在硬性（金属Alloys）或Mobiber（Metal Alloys）或Reservide（硫化物）之间。该项目是美国2个机构之间的一项协作努力，将在新颖的分析技术方面推广技术和专业知识，向USC新成立的地球化学设施。研究人员将共享一套最先进的仪器，包括FIB-SEM，FE-EMPA，FE-SEM，LA-ICPMS和Synchrotron Radiation Micro-X射线荧光。收集的所有数据将提交给PETDB和IEDA，并将通过CIW托管数据存储库向公众提供。来自南加州大学的研究生将参加他的博士学位研究。在海底暴露的改建的地幔岩石（称为“蛇形的深渊橄榄岩”）包含与继发性植物植物元素（PGE）硫化硫化物（硫化物）和PGE金属金属金属nugets相关的含有Ni含有的金属相。 PGE具有独特的物理和化学特性，对许多技术应用至关重要。因此，它们通常被视为在包括航空航天和燃料电池技术在内的广泛行业中的战略金属。拟议的研究将显着提高当前对高温海水改变对植物植物植物中植物植物硫化物分布的影响的有限理解。此外，深渊橄榄岩提供了重要的记录，以了解现在和过去的地球地面的组成和进化。拟议的工作是协作实验和自然样本研究。实验数据将在与现代深海火山相关的条件下定义PGE矿物质的热力学特性，并评估在升高温度/压力条件下Fe-Ni-Ru-Re-RE硫化物/合金中PGE溶解度机制的关键细节。合并的实验结果和自然样品数据将导致对橄榄岩改变橄榄岩的铁质脂肪和辣椒组成的影响及其对地球上OS和PB同位素异质性的影响的基本新理解。