Understanding the processes that affect isotopic ages to resolve both time and rates of geologic processes

了解影响同位素年龄的过程，以解决地质过程的时间和速率

• 批准号: RGPIN-2018-06023
• 负责人: Camacho, Alfredo
• 金额: $ 1.82万
• 依托单位: University of Manitoba
• 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=714038
• 关键词: Understanding; processes; affect; isotopic; ages

Plate tectonic theory provides a framework for understanding geologic processes that cycle material through Earth systems, and explains why earthquakes are localized along plate boundaries. It does not however, adequately explain tectonic processes in the interior of continents. Modern geodetic data show continental interiors are actively deforming, indicating tectonic activity is not limited to active plate boundaries. Variation of lithospheric strength is an important factor controlling the localization of deformation in continental interiors, and raises the key question: how do the mechanical properties of the lithosphere change during tectonic activity and time? Extraction of this temporal and thermal information on geologic systems requires understanding the interplay of physical processes determining the thermal structure of the lithosphere. The quantitative study of the thermal history of rocks using temperature-sensitive radiometric methods is called thermochronology, and involves dating the time at which a mineral passes through a specific closure temperature. Understanding how isotopes respond to temperature and deformation will provide new insights into the thermomechanical state of the lithosphere. In this grant cycle, I will study physicochemical factors affecting the mobility of isotopes in rocks to address the interplay between fracture and flow during deformation in the lower crust. Dramatic changes in mechanical rock property take place in this crustal region by increased pressure, temperature, and fluid activity. I hypothesize the diffusional redistribution of isotopes in a geologic system can take place under dry, static conditions, which has implications for diffusion rates and for determining the duration of thermal events. With these data, the bulk strength and dynamics of the lithosphere will be assessed by considering, in time and space, the interplay between brittle and ductile models. These potential interactions will be explored through several projects involving field and laboratory investigation with highly qualified personnel (HQP). The superbly exposed rocks in the Musgrave Ranges (Australia) and Bergen Arcs (Norway) are chosen as natural laboratories providing a unique insight into the development of lower crustal shear zones and allow models for lower crustal deformation to be evaluated critically. Although the host granulite (dry rock) of these two areas are similar, they differ in that the shear zones are dry in the Musgrave Ranges and wet in the Bergen Arcs. Results of this program are anticipated to yield both regional and widespread benefits for our country, such as developing the economic independence of Nunavut through improved access to traditional commodities like carving stone, and ensuring Canada's mineral exploration and extraction capabilities are able to excel in a competitive global marketplace.

板块构造理论为理解物质在地球系统中循环的地质过程提供了一个框架，并解释了为什么地震沿着板块边界定位。然而，它并不能充分解释大陆内部的构造过程。