Isotope and trace element evolution of the Naica aquifer (Chihuahua,Mexico) over the past 60,000 yr revealed by speleothems
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URI: http://hdl.handle.net/10835/15625
DOI: 10.1016/j.yqres.2013.09.004
DOI: 10.1016/j.yqres.2013.09.004
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Gázquez, Fernando; Calaforra, José María; Stoll, Heather; Sanna, Laura; Forti, Paolo; [et al.]Fecha
2013Resumen
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 condi...
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Geología
Mineralogía
Paleoclimatología