Sedimentary rock-hosted ore-forming systems: structural setting and paleohydrology

沉积岩成矿系统：构造背景和古水文

• 批准号: RGPIN-2019-05457
• 负责人: HICKEY, KENNETH
• 金额: $ 2.19万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=715558
• 关键词: Sedimentary; rock; hosted; ore; forming

Sedimentary rocks deposited in intracontinental and passive margin basins host a wide variety of hydrothermal ore-deposits that contain a significant percentage of global metal resources, especially lead, zinc, copper, and gold. These deposits form in a variety of ore-forming systems that operate at different periods of time as the basins progress through sequential stages of rifting, sedimentation, collision, deformation, erosion, and exhumation. The potential for ore-forming systems to generate deposits at any stage is strongly dependent on the overall hydrogeological framework of the basin, which is largely controlled by basin geometry, the permeability of sedimentary layers, and the density, geometry and permeability of cross-cutting structures. The long-term goal of my proposed research program is to evaluate how the physical and chemical evolution of sedimentary basins and their constituent sediments affects the potential for generating different types of sedimentary rock-hosted ore-deposits. This will be accomplished by comparing ore-forming systems operating at three different stages in the life cycle, from deposition to exhumation, of passive margin sediments: (1) sedimentary exhalative (SEDEX) Pb-Zn ore systems active during basin sedimentation prior to extensive lithification; (2) orogenic Au-systems active during deformation and low-grade metamorphism accompanying the incorporation of passive margin sediments into a foreland fold and thrust belt; and (3) Carlin-type Au-systems active nearly 300 million years after the host passive margin sediments were incorporated into a fold and thrust belt. My proposed research program will provide new constraints in understanding how the evolution of passive margin sedimentary basins influences the type of sedimentary rock-hosted ore-deposit that will form. The program encompasses field sites in the lower Paleozoic Selwyn Basin of the Yukon and Northwest Territories, and the laterally equivalent basin of central and eastern Nevada. First-order constraints on the hydrogeological framework under which the deposits formed will be provided by integrating extensive geological field observations, careful structural mapping, geochronology and geochemistry, taking advantage of recent advances in micro-analytical techniques and geochemical imaging. The extent to which the primary sedimentological character and subsequent diagenetic and structural evolution of host rocks is controlled by hydrothermal fluid flow and how early formed ore-deposits are modified by subsequent stages of collision and basin deformation will also be evaluated. The results will be used to advance conceptual models for the formation of sedimentary rock-hosted ore-deposits and their link to the life cycle of sedimentary basins, with implications for the exploration and discovery of metals vital to society.

沉积在陆内和被动边缘盆地中的沉积岩承载着各种各样的热液矿床，这些矿床含有全球金属资源的很大比例，特别是铅，锌，铜和金。这些矿床形成于各种成矿系统中，这些成矿系统在不同的时期运作，因为盆地经历了裂谷、沉积、碰撞、变形、侵蚀和折返的连续阶段。成矿系统在任何阶段生成矿床的潜力在很大程度上取决于盆地的总体水文地质框架，而总体水文地质框架在很大程度上受盆地几何形状、沉积层的渗透性以及横切构造的密度、几何形状和渗透性的控制。 我提出的研究计划的长期目标是评估沉积盆地及其组成沉积物的物理和化学演化如何影响生成不同类型沉积岩托管矿床的潜力。这将通过比较被动边缘沉积物从沉积到折返的生命周期中三个不同阶段的成矿系统来实现：（1）在广泛石化之前的盆地沉积期间活跃的沉积喷流（SEDEX）铅锌矿系统;（2）造山带变形期活动的金系统和低-级变质作用伴随着被动边缘沉积物并入前陆褶皱冲断带;卡林型金体系在被动大陆边缘沉积物并入褶皱冲断带后近3亿年才开始活动。 我提出的研究计划将提供新的限制，了解如何被动边缘沉积盆地的演化影响类型的沉积岩托管矿床，将形成。该计划包括育空地区和西北地区下古生代塞尔温盆地以及内华达州中部和东部横向等效盆地的现场。将通过综合广泛的地质实地观察、仔细的结构测绘、地质年代学和地球化学，利用微观分析技术和地球化学成像方面的最新进展，提供对矿床形成的水文地质框架的一级制约。还将评价热液流在多大程度上控制了主岩的主要沉积学特征和随后的成岩作用和结构演变，以及早期形成的矿床如何受到随后的碰撞和盆地变形阶段的影响。研究结果将用于推进沉积岩矿床形成的概念模型及其与沉积盆地生命周期的联系，并对对社会至关重要的金属的勘探和发现产生影响。