Potassium isotopes trace Earth's surface processes:Progress and challenges
Chemical weathering processes at the Earth's surface influence atmospheric CO2 and thus affect global climate change on different time scales.Therefore,how to effectively trace weathering processes is one of the important scientific issues in the field of supergene geochemistry.Potassium(K)has one valence state,is mainly hosted in silicate rocks and experiences distinct isotopic fractionation during supergene geochemical processes.These advantages allow K isotope systems to be a potential tracer for Earth's surface processes.However,the study of K isotopes is still in its early stage,so that there is no consensus on its fractionation mechanism and controlling factors.In this paper,the progress of K isotopes tracing Earth's surface processes is systematically reviewed from the aspects of K distribution,K isotopic compositions in major reservoirs,and fractionation behaviors of K isotopes during chemical weathering.Finally,in order to better understand the tracing of the Earth's surface processes using K isotopes,this study suggests combining large and small catchments,using multi-isotope systems,and quantifying the effects of human activities on K isotopic fractionation.
K isotopesEarth's surface processescontinental weatheringgeochemical tracing