Structural and tectonic evolution of orogenic belts, with an emphasis on kinematics of shear zones, Archean tectonics and implications for mineralization

造山带的结构和构造演化，重点是剪切带的运动学、太古代构造及其对矿化的影响

• 批准号: RGPIN-2014-04346
• 负责人: Lin, Shoufa
• 金额: $ 3.13万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=610976
• 关键词: Structural; tectonic; evolution; orogenic; belts

My long term objective of research is a better understanding of structural and tectonic evolution of mountain belts of various ages, evolution of tectonic processes through time and structural and tectonic control on mineralization. The proposed study will focus on three ancient mountain belts, the Archean Superior craton in Canada, the Proterozoic to Mesozoic South China Block and the Paleozoic Central Asian Orogenic Belt (CAOB) in China. My extensive experience with the Canadian Appalachians in the last two decades, one of the best studied orogens in the world, has proved to be very beneficial to our work in the Superior craton, the South China Block and the CAOB. A fundamental debate concerning Archean tectonic processes is that of vertical vs. horizontal tectonism. There is a tendency for advocates of plate tectonics (horizontal tectonism) in the Archean to downplay the significance, if not deny the presence, of vertical tectonism, and vice versa. Our work in the Superior craton has led to the recognition of evidence for both vertical and horizontal tectonism, and more importantly for their synchronous operation. We have proposed that synchronous vertical and horizontal tectonism was an important process in the Neoarchean and represented a transition from dominant vertical tectonism in the Meso-(and Paleo-?) Archean to dominant horizontal tectonism in Proterozoic and Phanerozoic. Such a conclusion makes it necessary that both processes (as opposed to either one or the other) and their potential interactions are considered in interpretations of Archean terrains. As importantly, we have suggested that such a process in the period of transition was important for gold mineralization, and the Hemlo deposit, a world-class deposit with >650 tons of gold, formed during the process. These interpretations were mostly based on data from the western, in particular the northwestern Superior craton. Here we propose to test these interpretations and their general applicability, not only through continuing work in the western Superior craton, but more importantly through additional work in the southeastern Superior craton, in particular in the Abitibi greenstone belt. The Abitibi belt is arguably the best studied and most prolific greenstone belt in the world, containing numerous world-class gold deposits. Vast amount of data is available concerning the belt and the deposits. In addition, the PI is familiar with the geology of the belt. These form a very good basis for the proposed study. As importantly, essentially all major gold deposits in the belt are spatially associated with two major shear zones in the area (the Desptor-Porcupine and Larder Lake-Cadillac faults) and the two shear zones spatially coincide with what appear to be synclinal keels between granitoid domes, as predicted by our model. This area thus provides an ideal opportunity to test the model. In addition, we will investigate the relative significance of vertical and horizontal tectonism and its variation with time and space (if any). We suspect that there exists a feedback relationship between the two processes and will explore the possible mechanisms for this. The results will have significant implications for Archean geological evolution in general and for Archean gold mineralization. The latter will help exploration targeting in Archean terranes worldwide. Our work in the South China Block and the CAOB will focus on the geometry, kinematics, and temporal evolution of major shear zones. The results will shed significant light on the tectonic evolution of these two accretionary orogens, in particular on the potential role of large-scale orogen-parallel motion along terrane-bounding shear zones in the amalgamation of the terranes.

我的研究的长期目标是更好地理解各个年龄段的山带的结构和构造演化，构造过程的演变以及矿化对矿化的结构和构造控制。拟议的研究将重点介绍三个古老的山带，加拿大的Archean Superior Craton，中世代中国中生代的procerokoic和中国的古生代中亚造山带（CAOB）。在过去的二十年中，我与加拿大阿巴拉契亚人的丰富经验，是世界上研究的牛根之一，已被证明对我们在上级克拉顿，中国南部和CAOB中的工作非常有益。 关于大将构造过程的基本辩论是垂直与水平构造的辩论。倡导板块构造的趋势（水平构造）倾向于淡化垂直构造的意义（即使不否认存在），反之亦然。我们在上级克拉顿（Craton）中的工作导致了垂直构造和水平构造的证据，更重要的是，它们的同步操作。我们提出，同步的垂直和水平构造是新结构中的一个重要过程，代表了从中植物学和phanerokoic中介质（和古 - ？）的显着垂直构造的过渡。这样的结论使得两个过程（相对于一个或另一个过程）有必要在天主地形的解释中考虑到它们的潜在相互作用。同样重要的是，我们建议在过渡时期的这种过程对于黄金矿化很重要，而在此过程中形成的世界一流的矿床是一种> 650吨黄金的世界一流沉积物。这些解释主要基于来自西方人的数据，尤其是西北高级克拉顿。在这里，我们建议通过在西部上级克拉顿（Craton）继续工作来测试这些解释及其一般的适用性，而且更重要的是，通过在东南上级克拉顿（Craton）（尤其是在阿比蒂比绿石带中）进行的其他工作。 Abitibi腰带可以说是世界上研究最多，最多产的绿石带，其中包含众多世界一流的黄金沉积物。有关皮带和沉积物的大量数据。此外，PI熟悉皮带的地质。这些是拟议研究的很好的基础。重要的是，皮带中的所有主要金矿在空间上都与该区域的两个主要剪切区（Desptor-Porcupine和Larder Lake-cadillac断层）相关，并且两个剪切带在空间上与似乎是synclinal龙骨在花岗素圆顶之间似乎是synclinal龙骨相吻合的，如我们的模型所示。因此，该领域为测试模型提供了理想的机会。此外，我们将研究垂直和水平构造的相对意义及其随时间和空间的变化（如果有）。我们怀疑这两个过程之间存在反馈关系，并将探索为此的可能机制。结果将对一般的大代地质进化和大古金矿化具有重要意义。后者将有助于探索全球大帝地形的探索目标。 我们在中国南部和CAOB的工作将集中在主要剪切区的几何形状，运动学和时间演变上。结果将对这两个增生性牛根的构造演化阐明，尤其是关于沿着地层的剪切区沿着地层融合的大规模造型 - 平行运动的潜在作用。