Weathering dynamics of Large Igneous Provinces (LIPs): A case study from the Lesotho Highlands

doi:10.1016/j.epsl.2019.115871

IEECAS OpenIR > 黄土与第四纪地质国家重点实验室（2010~）

	Weathering dynamics of Large Igneous Provinces (LIPs): A case study from the Lesotho Highlands
	Chen, Yang 1; Hedding, David William 2; Li, Xuming 1; Greyling, Abraham Carel 2; Li, Gaojun 1,3
通讯作者	Li, Gaojun(ligaojun@nju.edu.cn)
	2020-01-15
发表期刊	EARTH AND PLANETARY SCIENCE LETTERS
ISSN	0012-821X
卷号	530 页码:9
摘要	Basaltic terrains contribute a significant component to the global silicate weathering flux despite their limited areal coverage. A strong correlation between chemical weathering flux and climatic factors such as temperature in volcanically inactive basaltic fields implies that weathering of basalt might have played an important role in maintaining the habitability of the Earth and the balance of the geological carbon cycle. However, the low erosion rate of flood basalt provinces on tectonically quiescent cratons, where the clear climate dependence of weathering rate has been observed, implies a 'supply-limited' weathering regime so that weathering fluxes are expected to be controlled by physical erosion rather than climate. This work tests the weathering dynamics of flood basalts by investigating the weathering flux of the Karoo LIP on the Lesotho Highlands where an extremely low rate of denudation has been recorded through terrestrial cosmogenic nuclide dating and sediment flux. Stream chemistry of the rivers from the Lesotho Highlands shows typical characteristics of basalt weathering with Ca and Mg as the dominant cations and HCO3- as the dominant anion. Strong spatial and seasonal variability of solute concentration, possibly linked to a dilution effect, is observed. However, the giant Katse Reservoir of the Lesotho Highlands Water Project (LHWP) effectively averages the spatial and seasonal variability of the solute concentration. The average solution concentration and long-term runoff of the Katse Reservoir give an average atmospheric CO2 consumption rate of 0.26 +/- 0.02 x 10(6) mol/km(2)/yr (mean standard deviation). The chemical weathering flux requires complete alteration of primary silicates and, therefore, a 'supply-limited' weathering regime is suggested given the low denudation rate. Nevertheless, the chemical weathering rate of the Lesotho Highlands, as well as other low-eroding basaltic plateaus, is still consistent with the global correlation between temperature and the rate of basalt weathering. A production-limited denudation rate, modulated by temperature, is suggested to reconcile the paradox between the observed temperature dependence of chemical weathering rates and 'supply-limited' weathering regimes. (C) 2019 Elsevier B.V. All rights reserved.
关键词	soil regolith water-rock reaction landscape evolution critical zone
DOI	10.1016/j.epsl.2019.115871
关键词[WOS]	DRAKENSBERG ESCARPMENT ; DISSOLUTION KINETICS ; DENUDATION RATES ; CLIMATIC CONTROL ; EROSION RATES ; TEMPERATURE ; FLUXES ; BASIN ; CO2 ; AR-40/AR-39
收录类别	SCI ; SCI
语种	英语
资助项目	Natural Science Foundation of China[41761144058] ; Natural Science Foundation of China[41877351] ; Natural Science Foundation of China[41730101] ; National Research Foundation - South Africa[110777] ; SKLLQG, Institute of Earth Environment, CAS[SKLLQGZR1804]
WOS研究方向	Geochemistry & Geophysics
项目资助者	Natural Science Foundation of China ; National Research Foundation - South Africa ; SKLLQG, Institute of Earth Environment, CAS
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:000508747300010
出版者	ELSEVIER
引用统计	被引频次：13[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.ieecas.cn/handle/361006/13182
专题	黄土与第四纪地质国家重点实验室（2010~）
通讯作者	Li, Gaojun
作者单位	1.Nanjing Univ, Dept Earth & Planetary Sci, MOE Key Lab Surficial Geochem, Nanjing 210023, Peoples R China 2.Univ South Africa, Dept Geog, Pioneer Ave, ZA-1710 Florida, South Africa 3.Chinese Acad Sci, SKLLQG, Inst Earth Environm, Xian 710061, Peoples R China
推荐引用方式 GB/T 7714	Chen, Yang,Hedding, David William,Li, Xuming,et al. Weathering dynamics of Large Igneous Provinces (LIPs): A case study from the Lesotho Highlands[J]. EARTH AND PLANETARY SCIENCE LETTERS,2020,530:9.
APA	Chen, Yang,Hedding, David William,Li, Xuming,Greyling, Abraham Carel,&Li, Gaojun.(2020).Weathering dynamics of Large Igneous Provinces (LIPs): A case study from the Lesotho Highlands.EARTH AND PLANETARY SCIENCE LETTERS,530,9.
MLA	Chen, Yang,et al."Weathering dynamics of Large Igneous Provinces (LIPs): A case study from the Lesotho Highlands".EARTH AND PLANETARY SCIENCE LETTERS 530(2020):9.