CAREER: Understanding chemical weathering using lithium and potassium isotopes

GSTDTAP

项目编号	1848153
	CAREER: Understanding chemical weathering using lithium and potassium isotopes
	Xiao-Ming Liu (Principal Investigator)
主持机构	University of North Carolina at Chapel Hill
项目开始年	2019
	2019-04-01
项目结束日期	2024-03-31
资助机构	US-NSF
项目类别	Continuing grant
项目经费	311947(USD)
国家	美国
语种	英语
英文摘要	The chemical weathering or breakdown of rocks and minerals on Earth's surface transfers essential nutrients from the land surface to streams, groundwater, and eventually the oceans. Chemical weathering also consumes atmospheric CO2 and thus helps to regulate climate over millions of years, maintaining a long-term balance with volcanic emissions. Despite significant research, the processes that control chemical weathering remain uncertain and debated. This research project seeks to develop new techniques and innovative modeling approaches to study the rate and extent of chemical weathering of rocks and minerals on the surface of the Earth. The work will use existing knowledge of lithium isotope chemistry and will develop new knowledge in potassium isotope chemistry to measure weathering. The work will improve our understanding of the interactions between chemical weathering and climate on geologic time scales and the flux of elements into surface waters. Students from high school to PhD-level, including those from low-income households, first-generation college students, and members of under-represented groups will be trained in modern geochemical techniques. Results will be reported in conferences and peer-reviewed journals by students and researchers and introduced into college courses. The goals of this proposal are to advance the knowledge of Li and K isotope geochemistry and lay the foundation for using K isotopes as a new tracer of chemical weathering and especially silicate weathering. The approach is to systematically investigate Li and K isotopic variations during chemical weathering and examine the processes and mechanisms that may produce isotopic fractionation by performing laboratory experiments and studying well-characterized natural samples. Combining the development and application of the K with Li isotopes as chemical weathering proxies is the first attempt to disentangle different controls of chemical weathering in both laboratory and natural settings. Following recent studies on Li and K isotopes as weathering tracers, the PI proposes to 1) determine Li and K isotopic variation in fresh Hawaiian basalts, weathered rocks, soils, streams and ground waters; 2) quantify the magnitudes and mechanisms of Li and K isotope fractionation during chemical weathering; and 3) investigate whether K isotopes can be combined with Li isotopes as chemical weathering tracers. The development of the Li and K isotope weathering proxy will greatly enhance the understanding of chemical weathering and its impact on different tectonic and climatic factors. 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.
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/213087
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Xiao-Ming Liu .CAREER: Understanding chemical weathering using lithium and potassium isotopes.2019.