Tectonomagmatic history and ore-forming triggers at the Titiribi and La Mina porphyry-epithermal deposits, Colombia

哥伦比亚蒂蒂里比和拉米纳斑岩-浅成热液矿床的构造岩浆历史和成矿触发因素

• 批准号: 523133-2017
• 负责人: Richards, Jeremy
• 金额: $ 2.89万
• 依托单位: Laurentian University of Sudbury
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=663326
• 关键词: Tectonomagmatic; history; ore; forming; triggers

Porphyry copper deposits are major global sources of copper (as well as gold and molybdenum) to industry and society, and are premier targets for exploration by mining companies. The general mode of formation and occurrence of these deposits is now well understood by geologists, and involves the exsolution of hot metalliferous fluids from crystallizing magma in the upper crust (magmatic-hydrothermal fluids); the "fertile" magma that releases these fluids is typically formed above subduction zones at convergent plate boundaries, such as the Andes of South America, and the Cordillera of western North America. However, the ultimate controls on whether an economic deposit of metals is formed (as opposed to a low-grade deposit or barren system) are not well constrained, and indeed may be stochastic (inasmuch as they may not be predictable except in a probabilistic sense). It is noticeable that ore formation in porphyry systems occurs over short and singular periods of time (~100,000 years) in the overall history of the source magmatic system (1 to 5 million years), and commonly involves explosive brecciation and shallow magma emplacement, and yet many magmatic systems to not show evidence of such events. This suggests that a dramatic, perhaps catastrophic change occasionally affects otherwise passively crystallizing arc magmatic systems, leading to ore-formation. The nature of large ore deposits is that they display extensive overprinting and alteration, such that early textures that might reveal these triggering processes are destroyed. Therefore, we plan to study the relatively small Titiribi and La Mina porphyry deposits in Colombia, where the degree of overprinting is less, and early breccia and magmatic textures are well preserved. This will enable us to tightly constrain the interplay between magma emplacement, hydrothermal fluid release, and ore deposition, with the objective of identifying the underlying triggers for these processes. Although, ore formation may still be stochastic, understanding the key controls will improve predictability, thereby improving the ability to target exploration.

斑岩铜矿床是行业和社会的铜（以及黄金和钼）的主要全球来源，是矿业公司探索的主要目标。现在，地质学家对这些沉积物的形成和出现方式进行了充分理解，涉及在上壳中结晶岩浆（岩浆 - 热热液）的热量金属液体的溶液；释放这些液体的“肥沃”岩浆通常在收敛板边界（例如南美安第斯山脉）和北美西部山脉的俯冲带上形成。但是，关于是否形成金属的经济沉积物（与低级矿床或贫瘠的系统相对）的最终控制不是很好的约束，并且确实可能​​是随机的（因为除了概率意义上，它们可能是无法预测的）。值得注意的是，斑岩系统中的矿石形成发生在源岩浆系统（1至500万年）的整体历史上（约100，000年）（约100，000年）（1至500万年），并且通常涉及爆炸性的角色和浅层岩浆，但许多岩浆系统都没有显示此类事件的证据。这表明一种戏剧性的，可能的灾难性变化偶尔会影响否则被动地结晶的弧形岩浆系统，导致矿石形成。大型矿床的性质是它们表现出广泛的覆盖和变化，因此可能揭示这些触发过程的早期纹理被破坏了。因此，我们计划在哥伦比亚研究相对较小的替迪里比和拉米纳斑岩沉积物，那里的过度打印程度较小，而早期的角砾岩和岩浆质地则得到了很好的保存。这将使我们能够严格限制岩浆的相互作用，水热流体释放和矿石沉积，目的是识别这些过程的基础触发器。尽管矿石形成可能仍然是随机的，但了解关键控制措施将提高可预测性，从而提高靶向勘探能力。