Source-Transport-Trap Models for Base and Precious Metals in Basins

许多经济资源，如能源（石油和铀）和金属（铅、锌、铜和金）都是盆地尺度流体流动系统在盆地演化的不同阶段长时间运行的产物。沉积盆地承载经济资源的潜力取决于它们形成的环境、它们是如何变形的，以及随着时间的推移，流体是如何以及何时迁移并与岩石相互作用的。大多数矿化盆地通常只含有一种主要类型的经济矿床，然而，巴西中部的Vazante盆地是含有多种铅锌矿床类型和少量金矿的罕见例子之一。虽然人们普遍认识到，与沉积、成岩作用、变形、流体-岩石相互作用和挖掘有关的过程与各种类型的铅锌矿床的形成和保存有关，但关于这些金属经济集中的形成的过程仍然存在重要的未决问题。这在一定程度上是由于以前对盆地的大多数研究只集中在整个成矿过程的一个主要方面：要么是金属来源，要么是流体组成或流体流动动力学，要么是沉积机制。我的研究计划将通过应用整体和创新的方法来研究金属来源，运输和沉积的各个方面来解决尚未解决的问题。在接下来的五年里，我的研究团队将重点建立(a)锌和铅从可能的低浓度烃源岩中释放出来的机制；(b)它们如何以及何时被热流体输送，以及(c)是什么原因导致金属在经济矿床中沉淀。Vazante盆地拥有一种不寻常的硅酸盐锌矿床，以及由盆地内沉积岩与热流体相互作用形成的典型的铅锌硫化物矿床。因此，这是一个理想的环境，可以研究这些不同类型矿床形成的机制，并开发勘探模式，用于类似的环境（例如，加拿大的Mackenzie盆地）。我们想验证这样一个假设，即两种类型的贱金属矿床的金属来源和流体性质相似，但沉积过程不同，导致矿化区域的矿物学和成分存在重大差异。为了实现这些目标，我们将整合强大的现场和实验室工作，包括最先进的技术，与来自地球科学、地球化学和地球物理学各个领域的专家合作。本研究的预期效果是：(1)识别沉积盆地大型铅锌矿形成的关键控制因素，建立概念成因模型和勘探策略。这些发现将有助于确定更有可能拥有世界级贱金属矿床的盆地，特别是仍然稀有和知之甚少的大型硅酸盐锌矿床；(2)拟订综合各种学科的创新办法，并发展新技术，以了解金属从源岩中释放及其运输和沉积的过程（可能也适用于环境研究）；(3)最后，它将允许培养高素质的专业人员（1名硕士研究生和3名博士研究生和本科生），他们将学习获取和整合来自各个子学科的数据，并在高度协作的环境中开发新的方法和分析技术，为他们在学术界，政府和工业界工作做好准备。

Many economic resources such as energy (petroleum & uranium) and metals (lead, zinc, copper & gold) are products of basin-scale fluid flow systems operating over long periods of time and at distinct stages of basin evolution. The potential for sedimentary basins to host economic resources is a function of the environment in which they formed, how they were deformed and how and when fluids migrated and interacted with the rocks over time. Most mineralized basins normally host only one major type of economic deposit, however, the Vazante basin in central Brazil is one of the rare examples that hosts a variety of lead and zinc deposit types and minor gold occurrences. Although it is generally recognized that processes related to sedimentation, diagenesis, deformation, fluid-rock interaction and exhumation are relevant in the formation and preservation of the various types of lead and zinc deposits, there are still important open questions about the processes responsible for the formation of economic concentrations of these metals. This is due in part to the fact that most of the previous research on basins focused only on one major aspect of the entire ore-forming process: either the metal sources, or the fluid composition or fluid flow dynamics, or the depositional mechanisms. My research program will address the unresolved issues by applying a holistic and innovative approach to investigate all aspects of the source, transport and deposition of the metals. In the next five years, my research team will focus on establishing (a) the mechanisms by which zinc and lead are liberated from possible source rocks where they occur in low concentrations; (b) how and when they are transported by hot fluids and (c) what causes the metals to precipitate in economic ore deposits. The Vazante Basin hosts an unusual type of silicate zinc deposit, as well as the typical lead-zinc sulphide deposits formed by hot fluids interacting with sedimentary rocks in the basin. Therefore, it is an ideal setting in which to investigate the mechanisms responsible for the formation of these distinct types of deposits and develop exploration models to be used in similar settings (e.g., Mackenzie Basin in Canada). We would like to test the hypothesis that the source of metals and the nature of the fluids for both types of base metal deposits are similar, but the depositional processes are different, producing the major differences in the mineralogy and composition of the mineralized areas. To attain these objectives, we will integrate robust field and laboratory work, including the state-of-the art techniques, in collaboration with experts from the various fields of geoscience, geochemistry and geophysics. The expected impacts of this research are: (1) Identification of the critical factors that control the formation of large lead and zinc deposits in sedimentary basins, and the establishment of conceptual genetic models and exploration strategies. These findings will lead to the identification of basins that are more likely to host world-class base metal deposits, particularly large silicate zinc deposits which are still rare and poorly understood; (2) Elaboration of innovative approaches integrating various disciplines, and developing new techniques to understand the processes of metal liberation from source rocks, and their transport and deposition (possibly also applicable to environmental studies); (3) Finally, it will allow for the training of highly qualified professionals (1 M.Sc and 3 Ph.D students and undergraduate students) who will learn to acquire and integrate data from various subdisciplines and to develop new methodologies and analytical techniques in a highly collaborative environment, preparing them to work in academia, government and industry.