DOI: 10.1016/j.earscirev.2019.102938
论文题名: The hydrochemical evolution of alkaline volcanic lakes: a model to understand the South Atlantic Pre-salt mineral assemblages
作者: Mercedes-Martín R. ; Ayora C. ; Tritlla J. ; Sánchez-Román M.
刊名: Earth Science Reviews
ISSN: 00128252
出版年: 2019
卷: 198 语种: 英语
中文关键词: Baringo
; Calcite
; Hydrologically open basin
; Lacustrine
; Magnesium-rich clay
; PHREEQC
; Pre-salt
; Silica
英文关键词: alkaline water
; calcite
; clay
; lacustrine environment
; leakage
; magnesium
; precipitation (chemistry)
; saline lake
; silica
; water chemistry
; Atlantic Ocean
; Atlantic Ocean (South)
; Baringo
; Kenya
; Lake Baringo
英文摘要: Understand the origin of the exotic strontium-rich calcite/magnesium-rich clay/silica deposits formed during the Early Cretaceous in the South Atlantic Pre-salt lakes is challenging our ability to comprehend the chemical evolution of alkaline volcanic lakes. Here we present a new hydrochemical model based on an open basin concept, thermodynamic equilibrium, and chemical data from Lake Baringo (East African Rift) to shed light on the mechanisms facilitating carbonate-clay-silica precipitation. This model explores the effects that the leakage to adjacent waterbodies, the combination of lake evaporation and lake recharge (with river, hydrothermal and marine waters), and the bathymetric effects of the partial CO2 pressure have in the stationary precipitation of Pre-salt lacustrine mineral assemblages. Sediment thickness calculations suggest that the facies cyclicity in the Pre-salt and elsewhere are likely reflecting temporal fluctuations in the type of waters sourcing the lake, and in the degree of leakage to aquifers over multiple evaporative-freshening cycles. A plausible link between enhanced strontium uptake into Pre-salt calcite allochems and [Ca2+]/[CO3 2−] lake water stoichiometries allows to infer different scenarios for strontium-rich calcite formation with or without magnesium clays. Our conceptual model allows to quantify the role that hydrology (groundwater charge, discharge to aquifers; evaporation) exert on carbonate-clay-silica precipitation providing with a refined framework to understand the basin-scale chemical sedimentation in alkaline lakes. Furthermore, this model represents a robust template upon which critically test the superimposed kinetic factors likely attached to the genesis of specific mineral factories such as those encountered in the South Atlantic Pre-salt alkaline lakes. © 2019 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165880
Appears in Collections: 气候变化与战略
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作者单位: SZALAI Grup S.L., P.O Box 1005, Caimari, 07314, Spain; Departament de Geociències, Institut de Diagnosi Ambiental i Estudis de l'Aigua (IDÆA-CSIC), Barcelona, Spain; REPSOL Exploración S.A, C/Méndez Álvaro 44, Madrid, Spain; Earth Sciences Department, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1086, Amsterdam, HV 1081, Netherlands
Recommended Citation:
Mercedes-Martín R.,Ayora C.,Tritlla J.,et al. The hydrochemical evolution of alkaline volcanic lakes: a model to understand the South Atlantic Pre-salt mineral assemblages[J]. Earth Science Reviews,2019-01-01,198