EAR-PF: A Deep Critical Zone Observatory: Towards understanding the relationships of denudation and weathering through time and space

Brendon Quirk博士被授予NSF EAR博士后奖学金，研究全球气候条件和利用湖泊沉积物分解岩石的关系。这项工作将在普渡大学Darryl Granger博士的指导下进行。了解岩石是如何分解的（天气），以及在整个地质历史中产生的物质是如何运输的（侵蚀），对于了解地球气候是如何演变的至关重要。具体来说，通过化学反应分解岩石可能有助于稳定全球气候，并产生一个可居住的地球。这项工作将利用湖泊沉积物来了解不同的气候条件如何影响地球表面岩石和土壤的风化和侵蚀速率。预期的结果将有助于评估地质历史上特定的风化和侵蚀模式，并可能阐明侵蚀、风化和气候之间潜在的自然反馈。该项目包括为第一代大学生开展研究的外展和指导计划。开发易于使用的实验室技术，以减少进行全球气候研究的障碍，是本研究支持的另一项活动。了解地球表面的剥蚀（物理和化学风化通量的总和）随时间和空间的变化仍然是地球科学中最紧迫的问题之一。硅酸盐矿物的化学风化作用被认为是调节全球碳循环的主要过程之一。因此，剥蚀作用可能在地质时间尺度上稳定全球气候，并且可能是地球可居住性的重要因素。然而，第四纪陆地剥蚀和风化的高分辨率记录是罕见的，并且侵蚀和风化是否以及如何相互作用以调节和稳定跨间冰期-冰期时间尺度的化学风化通量仍然存在问题。这里提出的工作旨在通过量化跨越几个冰期-间冰期旋回的古剥蚀和风化速率来解决这些悬而未决的问题。该项目将使用成熟的方法来量化湖泊沉积物档案中的古剥蚀（原位宇宙成因Be-10）和风化强度（化学损耗分数），并校准有前途的新方法（Be-10（大气）/Be-9），以量化细粒，石英贫乏的湖泊沉积物。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Dr. Brendon Quirk has been awarded an NSF EAR Postdoctoral Fellowship to study the relationship of global climate conditions and the breakdown of rocks using lake sediments. The work will be conducted at Purdue University under the mentorship of Dr. Darryl Granger. Understanding how rocks break down (weather) and how the resulting material is transported (erosion) throughout geologic history is critical for understanding how Earth’s climate has evolved. Specifically, the breakdown of rock through chemical reactions may help to stabilize global climate and produce a habitable Earth. This work will use lake sediments to understand how different climate conditions affect rates of weathering and erosion of rock and soil across Earth’s surface. The anticipated results will be useful for evaluating specific models of weathering and erosion in geologic history and may shed light on potential natural feedbacks between erosion, weathering, and climate. The project includes outreach and mentoring programs for first-generation college students to conduct research. The development of accessible laboratory techniques designed to reduce barriers to conducting research into global climate is another activity supported by this research. Understanding variations in denudation (the sum of physical and chemical weathering fluxes) of Earth’s surface through time and space remains one of most pressing problems in the earth sciences. Chemical weathering of silicate minerals is thought to be one of the main processes which regulate the global carbon cycle. Thus, denudation may act to stabilize global climate over geologic timescales and may be an important factor in earth’s habitability. However, high-resolution records of terrestrial denudation and weathering for the Quaternary period are rare and questions remain if and how erosion and weathering might interact to regulate and stabilize the chemical weathering flux across interglacial-glacial timescales. The work proposed here seeks to address these outstanding questions by quantifying paleo-denudation and weathering rates spanning several glacial-interglacial cycles. This project will use well established methods to quantify paleo-denudation (in situ cosmogenic Be-10) and weathering intensities (chemical depletion fractions) in lacustrine sediment archives as well as calibrate promising new methods (Be-10(meteoric)/Be-9) to quantify each from fine grained, quartz-poor, lake sediments.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.