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Isotope and trace element evolution of the Naica aquifer (Chihuahua, Mexico) over the past 60,000 yr revealed by speleothems

Gázquez, Fernando and Calaforra, José María and Stoll, Heather and Sanna, Laura and Forti, Paolo and Lauritzen, Stein-Erik and Delgado, Antonio and Rull, Fernando and Martínez-Frías, Jesús (2013) Isotope and trace element evolution of the Naica aquifer (Chihuahua, Mexico) over the past 60,000 yr revealed by speleothems. Quaternary Research, Vol. 80 (3), p. 510-521. ISSN 0033-5894. eISSN 1096-0287. Article.

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DOI: 10.1016/j.yqres.2013.09.004

Abstract

The “espada” speleothems of Cueva de las Espadas (Naica Mine, Chihuahua, Mexico) comprise a high-purity selenite core overlain by successive deposits of calcite, gypsum and aragonite. Gypsum precipitated under water from a hydrothermal solution (~ 58°C) when the water table was above the cave level ca. 57 ka, during the last glaciation, and some intervals during deglaciation and the Holocene. Aragonite was deposited at lower temperatures (~ 26°C) in a perched lake occupying the cave bottom, when the water table dropped below the cave level during brief dry intervals during deglaciation and the early Holocene. The isotopic composition of gypsum water of crystallization shows that the deglaciation–Holocene aquifer water was enriched in deuterium by 12.8–8.7‰ relative to water from the last glaciation. This is attributed to an increased relative moisture contribution from the Gulf of Mexico during deglaciation and the Holocene compared to the last glaciation. This indicates that drier conditions occurred in the Naica area during the Holocene than around 57 ka. Furthermore, trace element analyses of gypsum served to deduce the circulation regime of the Naica aquifer during the past 60,000 yr, and also suggest that higher aquifer recharge occurred during the last glaciation.

Item Type:Article
ID Code:9776
Status:Published
Refereed:Yes
Uncontrolled Keywords:Cave minerals, gypsum water of crystallization, gypsum speleothems, naica caves, paleogroundwater, selenite
Subjects:Area 04 - Scienze della terra > GEO/09 Georisorse minerarie e applicazioni mineralogico- petrografiche per l'ambiente ed i beni culturali
Divisions:001 Università di Sassari > 01-a Nuovi Dipartimenti dal 2012 > Scienze della Natura e del Territorio
Publisher:Academic Press
ISSN:0033-5894
eISSN:1096-0287
Copyright Holders:© University of Washington. Published by Elsevier Inc. All rights reserved
Deposited On:02 May 2014 10:37

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