Applied thermochronology and the timing of brittle-ductile crustal-scale tectonic processes

应用热年代学和脆性地壳尺度构造过程的计时

• 批准号: RGPIN-2019-04604
• 负责人: Schneider, David
• 金额: $ 4.47万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=691106
• 关键词: Applied; thermochronology; timing; brittle; ductile

Broad tectonic stresses over the Earth's outer solid shell cause localized deformation along fault zones. Deformation leads to the displacement of rock, and this large-scale movement of heat and fluids during mountain building exerts a major control on burial, heating and potential mineral transformation, and plays a key role in the distribution of economic ore deposits and hydrocarbon reservoirs. Understanding the tempo of these tectonic events across deep time is fundamental for making predictions about the solid Earth on shorter timescales. However, rock structures, such as faults, joints, and cleavage, that formed under low-temperature conditions (100-450C) are difficult to date, despite the usefulness of this information for resolving the shallow crustal history of the Earth. This low-temperature crustal domain lies within the extremes of surficial processes governing the interactions between deformation-erosion and climate-topography feedback mechanisms, and the now exposed roots of mountain belts that provide insights into magma generation and midcrustal flow. As rocks pass through the these low-temperature ranges, they experience a transition from brittle to plastic deformation mechanisms, undergo significant dehydration and reach the peak of mechanical strength. As such, this transition zone controls the location, localization and displacement of major crustal fault zones and is a potential clutch between surface topography and deeper portions of the Earth. Developing new, and improving existing, dating technologies that are capable of capturing the timing of deformation is the long-term goal of my research. The innovative geochronometers that specifically cover this temperature range which my research group is currently focusing on include U-bearing and K-bearing minerals, including common calcite and iron oxides. Notably, we are partly focusing on deformed carbonate-dominated regions since they present significant challenges for geochronology as they lack the traditional minerals required for such analyses. Together with Discovery Grant support, my work embarks upon a new phase of Earth science research involving students and international collaborators, developing innovative low-temperature geochronology techniques, and rewarding my students with having access to, and training on, world-class instruments. Although concentrating on fundamental issues such as the life cycle of mountain belts, this research has impacts through the Earth Sciences, from submicron-scale isotope mobility to mega-scale tectonism. More directly, this research has specific applications to natural resource exploration, including determining the timing and duration of ore-bearing fluid flow and the burial history of petroleum reservoirs.

地球固体外壳上广泛的构造应力引起了沿着断层带的局部变形。变形导致岩石位移，这种造山过程中的大规模热流体运动对埋藏、加热和潜在矿物转化起着重要的控制作用，对经济矿床和油气藏的分布起着关键作用。了解这些构造事件在深时间的克里思是在较短时间尺度上预测固体地球的基础。然而，在低温条件下（100- 450 ℃）形成的岩石结构，如断层、节理和劈理，很难确定年代，尽管这些信息对解决地球浅层地壳历史很有用。这个低温地壳域位于地表过程的极端之内，这些过程控制着变形-侵蚀和气候-地形反馈机制之间的相互作用，而现在暴露的山脉根部则为岩浆生成和中地壳流动提供了见解。当岩石通过这些低温范围时，它们经历从脆性到塑性变形机制的转变，经历显著的脱水并达到机械强度的峰值。因此，这个过渡带控制着主要地壳断层带的位置、定位和位移，是地表地形和地球深部之间的潜在离合器。开发新的、改进现有的、能够捕捉变形时间的测年技术是我研究的长期目标。我的研究小组目前正在关注的专门涵盖这一温度范围的创新地质年代计包括含铀和含钾矿物，包括常见的方解石和氧化铁。值得注意的是，我们部分关注变形碳酸盐为主的地区，因为它们缺乏这种分析所需的传统矿物，对地质年代学提出了重大挑战。与发现补助金的支持一起，我的工作开始了地球科学研究的新阶段，涉及学生和国际合作者，开发创新的低温地质年代学技术，并奖励我的学生获得，并在世界一流的仪器上进行培训。虽然集中在基本问题，如生命周期的山区带，这项研究的影响，通过地球科学，从亚微米尺度的同位素流动性的大规模构造。更直接地说，这项研究在自然资源勘探中有具体的应用，包括确定含矿流体流动的时间和持续时间以及石油储层的埋藏历史。