Structural and tectonic evolution of orogenic belts, with an emphasis on kinematics of shear zones, accretionary/collisional orogens and Archean tectonics

造山带的结构和构造演化，重点是剪切带、增生/碰撞造山带和太古代构造运动学

• 批准号: RGPIN-2019-04305
• 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: 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=714767
• 关键词: Structural; tectonic; evolution; orogenic; belts

The long term goal of my research is to develop a stronger understanding of structural and tectonic evolution of mountain belts, the evolution of tectonic processes through time, and the structural and tectonic control on mineralization. The proposed study will focus on three ancient mountain belts of contrasting ages and styles: the Proterozoic to Mesozoic South China Block and the Paleozoic Central Asian Orogenic Belt (CAOB) in China and the Archean Superior craton in Canada. Continental margins, especially passive margins, commonly have irregular shapes and exhibit promontories and reentrants. Where this is the case, collision between two continents is expected to start at a promontory or between two promontories. This has major implications for tectonic evolution of orogens, but has drawn only limited attention. A better understanding of the role of irregular continental margins in collision through a study of the Early Paleozoic Orogen in South China is one of the objectives of the proposed study. Promontory collision offers a solution to the biggest puzzle concerning South China in the early Paleozoic, that is, a major tectono-thermal event in South China, with characters of a collisional orogeny, took place tens of millions of years after the Gondwana supercontinent had been assembled and collision appeared to have been over. Our work in the CAOB will focus on the timing and processes of the final closure of the Paleo-Asian Ocean, through a detailed study of a Carboniferous-Permian volcano-sedimentary sequence and syntectonic intrusions and a potential ophiolite sequence. We will also pay special attention to the geometry, kinematics, temporal evolution and the tectonic significance of major terrane-bounding shear zones. Our work on 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 the Proterozoic and Phanerozoic. We will continue to test these interpretations and their general applicability. Our field-based study will be aided by numerical modelling, using a new code developed by our team that covers the time component by solving a generalized non-steady system with finite element method. The code is optimal for simulating geological processes with large deformation and for examining structural evolution in complex orogenic processes. These research efforts will train at least five graduate and many more undergraduate students in structural geology and tectonics. They will gain a competitive edge from our field-based, multidisciplinary and collaborative research experience.

我研究的长期目标是对山地带的构造和构造演化、构造过程随时间的演化以及构造和构造对矿化的控制有更深入的了解。拟议的研究将重点关注三个年龄和风格截然不同的古代山地带：中国的元古代至中生代华南地块和古生代中亚造山带（CAOB）以及加拿大的太古代上克拉通。 大陆边缘，尤其是被动边缘，通常具有不规则的形状并表现出海角和凹角。在这种情况下，两个大陆之间的碰撞预计将从一个海角或两个海角之间开始。这对造山带的构造演化具有重大意义，但只引起了有限的关注。通过对华南早古生代造山带的研究，更好地了解不规则大陆边缘在碰撞中的作用是本研究的目标之一。海岬碰撞解决了早古生代华南最大的难题，即在冈瓦纳超大陆聚集、碰撞似乎已经结束之后的几千万年，华南地区发生了一次具有碰撞造山运动特征的重大构造热事件。 我们在 CAOB 的工作将通过对石炭纪-二叠纪火山沉积序列和同构造侵入体以及潜在的蛇绿岩序列的详细研究，重点关注古亚洲洋最终闭合的时间和过程。我们还将特别关注主要地体边界剪切带的几何、运动学、时间演化和构造意义。 我们对上克拉通的研究使人们认识到垂直和水平构造运动的证据，更重要的是，认识到它们同步运行的证据。我们提出，同步的垂直和水平构造作用是新太古代的一个重要过程，代表着从中古宙（和古？）太古宙的垂直构造作用占主导地位到元古代和显生宙的水平构造作用占主导地位的转变。我们将继续测试这些解释及其普遍适用性。 我们的现场研究将得到数值建模的帮助，使用我们团队开发的新代码，通过有限元方法求解广义非稳态系统来涵盖时间分量。该代码非常适合模拟大变形的地质过程以及检查复杂造山过程中的结构演化。 这些研究工作将培训至少五名构造地质学和构造学研究生和更多本科生。他们将从我们的实地、多学科和协作研究经验中获得竞争优势。