Tracing element migration in the geosphere and biosphere

我研究的长期目标是了解元素在近地表环境(即地质圈)和地质圈与动植物(即生物圈)之间的界面上的迁移。这项研究涉及环境科学和矿产勘探，由纯研究和应用研究两部分组成，将涉及3名理科学士、2名理学硕士、5名博士、5名PDF和2名研究助理。这项研究背后的科学原理是，可以通过元素的同位素(一种元素的质子数量相同，但中子数量不同)和浓度来确定元素的来源，从而确定埋藏金属矿床的预期区域和原始区域的污染输入。 在接下来的五年里，我的研究计划将围绕两个不同但又相互关联的主题展开：(1)矿产资源，这将涉及通过同位素追踪元素从矿藏深处的迁移，并将它们捕获在近地表；(2)地圈-生物圈相互作用，将从隐蔽矿藏迁移的元素与来自全球污染的元素区分开来，利用土壤和树轮中的这些元素来帮助寻找更多埋藏的矿藏，并更好地跟踪动物的迁徙习性，因为它们与特定的岩石单位相互作用。 (1)矿产资源变得更加难以寻找，因为大多数暴露在地表的矿产资源都已被发现。我们将研究已知矿藏的区域，包括萨斯喀彻温省的铀和马尼托巴省的铜和镍。将收集来自矿床的钻芯样本、上覆地质以及地表的土壤和树木。将收集钻芯和上覆样品，表征它们的矿物组成，并测量它们的化学和元素同位素。我们开发的技术将用于测量元素含量及其在样品中的位置，以及它们的同位素。对于土壤，粘土矿物将被提取，因为它们能够捕获迁移的元素。将测量它们的化学和同位素组成，以确定从沉积物中活化的元素。还将提取粘土和土壤中的碳氢化合物及其同位素组成，以了解微生物在动员元素并将其固定在近地表环境中的作用。在这一过程中，将对几名HQP进行多维研究和分析地球化学方面的培训。 (2)地圈-生物圈的相互作用将涉及利用树轮和来自其他地表介质的补充数据来区分金属的沉积来源和污染源。此外，作为未来五年合作努力的一部分，我将参与使用同位素追踪元素从海洋、湖泊和风吹源迁移到土壤中产生碳酸盐的研究。这项研究将包括利用“生物活性”微量元素和选定的同位素来破译干旱湖泊环境和土壤中碳酸盐的特征，以揭示微生物过程对碳酸盐生产的影响。在一项补充研究中，将通过氢、碳和氮(均具有生物活性)的同位素以及羽毛、血液和脚趾甲中的微量元素来追踪鸟类的迁徙习性，以反映鸟类生长这些器官的地质条件。该项目将首次整合同位素、微量元素、组织形态和生物数据，以追踪影响候鸟数量下降的因素。尽管表面上存在差异，但所有这项研究都涉及使用同位素和元素含量来有效追踪元素在近地表环境中的运动，以实现纯研究和应用研究的目标。

The long-term goal of my research is to understand the migration of elements throughout the near-surface environment (i.e. geosphere) and across the interface between the geosphere and plants and animals (i.e. biosphere). This research involves both environmental sciences and mineral exploration, is comprised of both pure and applied research components, and will involve 3 BSc, 2 MSc, 5 PhD, 5 PDF and 2 Research Associates. The science behind this research is that sources of elements can be definitively identified in environments near the surface through their isotopes (same number of protons but different number of neutrons for an element) and concentrations, thereby identifying prospective areas for buried metal deposits and inputs of pollution in pristine areas. My research program during the next five years will focus along two diverse yet related themes: (1) mineral resources, which will involve tracing element migration from ore deposits at depth via their isotopes and trapping of them in the near-surface, and (2) geosphere-biosphere interactions, which will distinguish elements that have migrated from undercover ore deposits from those that have come from global pollution, using these elements in soils and tree-rings to help find more buried ore deposits, and to better track the migratory habits of animals because they have interacted with specific rock units. (1) Mineral resources have become more difficult to find since most of those exposed at the surface have been discovered. We will study areas of known deposits that include uranium in Saskatchewan and copper and nickel in Manitoba. Samples of drill core from the deposit, the overlying geology, and soils and trees at the surface will be collected. Drill core and overlying samples will collected, their mineral compositions characterized, and their chemistry and isotopes of elements measured. Techniques we have developed will be used to measure both element contents and their location in the samples, as well as their isotopes. For the soils, the clay minerals will be extracted because they are able to trap migrating elements. Their chemical and isotopic compositions will be measured to identify elements mobilized from the deposits. Hydrocarbons from clays and soils and their isotopic compositions also will be extracted to understand the role of microbes in mobilizing elements and fixing them in the near-surface environment. In the process, several HQP will be trained in multi-dimensional research and analytical geochemistry. (2) Geosphere-biosphere interactions will involve the use of tree-rings and complementary data from other surface media to distinguish deposit and pollution sources of metals. Also, as part of a collaborative effort over the next five years, I will be engaged in research using isotopes to trace element migration from oceanic, lake and wind-blown sources to produce carbonates in soils. This research will involve deciphering the character of carbonates in arid lake environments and in soils using “bio-active” trace elements and selected isotopes to reveal the effects of microbial processes on carbonate production. In a complementary study, migratory habits of birds will be traced with isotopes of hydrogen, carbon and nitrogen (all bio-active) and trace elements in feathers, blood and toenails to reflect the geology in which the birds grow these organs. This project will be the first to integrate isotope, trace elements, tissue morphology and biologic data to trace factors affecting the declining populations of migrating birds. Despite the seeming disparity, all of this research involves using isotopes and element contents to effectively trace the movement of elements in the near-surface environment for both pure and applied research goals.