Fluids in the continental crust: decrypting geological processes using noble gases

大陆地壳中的流体：利用稀有气体解密地质过程

• 批准号: RGPIN-2015-05378
• 负责人: Pinti, Daniele
• 金额: $ 1.6万
• 依托单位: Université du Québec à Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=678691
• 关键词: Fluids; continental; crust; decrypting; geological

The research program will focus on the origin and evolution of fluids in the lithosphere and the critical role they play in the geodynamical evolution of the continental crust. It will address fundamental questions about i) the duration and length of cross-formational fluid flow and its role in the crustal degassing; ii) the existence of fossil water as geological archives of the continental crust evolution; iii) the genesis and evolution of crustal fluids of economic interest, particularly geothermal fluids and shale gas.****To meet these objectives, a series of projects will be undertaken in sedimentary and hydrothermal environments - at different spatial and temporal scales. Some focus will be put on the processes responsible for vertical migration of gaseous species (methane, helium.) in aquifers, and the genesis of seepage on continents, with natural laboratory being the St. Lawrence Lowlands (QC). Studies will be aimed at quantifying methane fluxes and model the process of transport from Utica shale. These models will be translated to the Island of Anticosti where tight gas exploitation is sought. Another important aspect that will be explored is the occurrence of hundreds millions to billions years old fluids in deep mining environments and their role in mineralization along the Cadillac fault in Abitibi-Temiscamingue. Parallel to this NSERC research program, we are carrying out a detailed study of the evolution of hydrothermal fluids in the largest active geothermal systems of Mexico in order to assess their lifetime and power capacities. These hydrothermal environments are the modern analogue of the fossil epithermal ore deposits. The large chemical and isotopic database that will be acquired will be crucial to understand the relation between metals and fluid sources in these environments, a premise to future ore genesis models. The tremendous and unique expertise we are developing on geothermal systems will be also applied to the study of the geothermal capacity of some Canadian Provinces, in particular the genesis of the Banff's geothermal area.****The methodological approach to trace the origin and evolution of these "geofluids" is based on the isotopes of conservative elements, namely noble gases, for which I have a unique expertise in Canada. Being chemically inert, scarce and sourced from isotopically distinct reservoirs, noble gases are ideal fluid tracers. Several isotopes are products of radioactive decay, opening opportunities of dating fluids on timescales going to a few years to billions of years.****This research program represents a unique opportunity for young HQP to acquire a multi-disciplinary scientific, analytical and professional experience, in the study of the water cycle and its dynamic (behavior) in the continental crust, while specializing in a challenging and rewarding scientific discipline that is the noble gas geochemistry.**

该研究计划将侧重于岩石圈中流体的起源和演化，以及它们在大陆地壳地球动力学演化中所起的关键作用。它将讨论以下基本问题：1)跨地层流体流动的持续时间和长度及其在地壳脱气过程中的作用；2)作为大陆地壳演化地质档案的化石水的存在；3)具有经济意义的地壳流体，特别是地热流体和页岩气的成因和演化。一些重点将放在负责气体物种(甲烷、氦)垂直迁移的过程上。与圣劳伦斯低地(QC)的自然实验室合作，研究含水层的渗漏和大陆渗漏的成因。研究的目的将是量化甲烷通量，并对尤蒂卡页岩的运输过程进行建模。这些模型将被翻译到安提科里岛，在那里寻求致密天然气开采。将探索的另一个重要方面是深部采矿环境中存在数亿至数十亿年的流体，以及它们在Abitibi-Temiscamingue的凯迪拉克断层上的成矿作用。与NSERC的这一研究计划同时，我们正在对墨西哥最大的活跃地热系统中热液流体的演化进行详细研究，以评估它们的寿命和发电能力。这些热液环境是化石浅成热液矿床的现代类比。将获得的大型化学和同位素数据库将对了解这些环境中金属和流体来源之间的关系至关重要，这是未来矿床成因模型的前提。我们正在开发的关于地热系统的巨大而独特的专业知识也将被用于研究加拿大一些省份的地热容量，特别是班夫地热区的成因。*追踪这些“地球流体”起源和演化的方法是基于保守元素的同位素，即惰性气体，在这方面我在加拿大有独特的专业知识。惰性气体是化学惰性的，稀有，来自同位素不同的储集层，是理想的流体示踪剂。几种同位素是放射性衰变的产物，为几年到数十亿年的时间尺度上的流体测年打开了机会。*这项研究计划为年轻的HQP提供了一个独特的机会，让他们获得多学科的科学、分析和专业经验，研究大陆地壳中的水循环及其动态(行为)，同时专门从事一门具有挑战性和回报的科学学科，即稀有气体地球化学。**