气候变化领域集成服务门户(CCPortal): When "evaporites" are not formed by evaporation: The role of temperature and pCO2 on saline deposits of the Eocene Green River Formation, Colorado, USA

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DOI	10.1130/B35303.1
	When "evaporites" are not formed by evaporation: The role of temperature and pCO2 on saline deposits of the Eocene Green River Formation, Colorado, USA
	Demicco R.V.; Lowenstein T.K.
发表日期	2020
ISSN	167606
起始页码	1365
结束页码	1380
卷号	132 期号:2021-07-08
英文摘要	Halite precipitates in the Dead Sea during winter but re-dissolves above the thermocline upon summer warming, "focusing" halite deposition below the thermocline (Sirota et al., 2016, 2017, 2018). Here we develop an "evaporite focusing" model for evaporites (nahcolite + halite) preserved in a restricted area of the Eocene Green River Formation in the Piceance Creek Basin of Colorado, USA. Nahcolite solubility is dependent on partial pressure of carbon dioxide (pCO2) as well as temperature (T), so these models covary with both T and pCO2. In the lake that filled the Piceance Creek Basin, halite, nahcolite or mixtures of both could have precipitated during winter cooling, depending on the CO2 content in different parts of the lake. Preservation of these minerals occurs below the thermocline (>~25 m) in deeper portions of the basin. Our modeling addresses both: (1) the restriction of evaporites in the Piceance Creek Basin to the center of the basin without recourse to later dissolution and (2) the variable mineralogy of the evaporites without recourse to changes in lake water chemistry. T from 20 to 30 °C and pCO2 between 1800 and 2800 ppm are reasonable estimates for the conditions in the Piceance Creek Basin paleolake. Other evaporites occur in the center of basins but do not extend out to the edges of the basin. Evaporite focusing caused by summer-winter T changes in the solubility of the minerals should be considered for such deposits and variable pCO2 within the evaporating brines also needs to be considered if pCO2 sensitive minerals are found. © 2019 Geological Society of America.
语种	英语
来源期刊	Bulletin of the Geological Society of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/184748
作者单位	Department of Geological Sciences and Environmental Studies, Binghamton University, Binghamton, NY 13902-6000, United States
推荐引用方式 GB/T 7714	Demicco R.V.,Lowenstein T.K.. When "evaporites" are not formed by evaporation: The role of temperature and pCO2 on saline deposits of the Eocene Green River Formation, Colorado, USA[J],2020,132(2021-07-08).
APA	Demicco R.V.,&Lowenstein T.K..(2020).When "evaporites" are not formed by evaporation: The role of temperature and pCO2 on saline deposits of the Eocene Green River Formation, Colorado, USA.Bulletin of the Geological Society of America,132(2021-07-08).
MLA	Demicco R.V.,et al."When "evaporites" are not formed by evaporation: The role of temperature and pCO2 on saline deposits of the Eocene Green River Formation, Colorado, USA".Bulletin of the Geological Society of America 132.2021-07-08(2020).