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Porosity and hydric behavior of typical calcite microfabrics in stalagmites

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Muñoz García, Mercedes and López Arce, Paula and Fernández Valle, Mª Encarnación and Martín Chivelet, Javier and Fort González, Rafael (2012) Porosity and hydric behavior of typical calcite microfabrics in stalagmites. Sedimentary Geology, 265-266 . pp. 72-86. ISSN 0037-0738

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Official URL: http://www.elsevier.com/wps/product/cws_home/503361/description



Abstract

Petrophysical techniques commonly used for material characterization are applied for the first time to
speleothem samples to investigate the porosity and hydric behavior of calcite stalagmites used in paleoclimatology.
These techniques allow the determination of the stalagmites' potential to undergo diagenetic transformations
when substantial changes in drip waters occur in the cave environment. The petrophysical
techniques include water absorption under vacuum and by capillarity, nuclear magnetic resonance, environmental
scanning electron microscopy, and mercury intrusion porosimetry. The studied samples comprise five
common calcite microfabrics, which have markedly different porosities and hydric behaviors and, as a consequence,
different sensibilities to diagenetic processes related to the influx of water. The experiments show
that stalagmites can behave as complex, small-scale hydrological systems and that the circulation of water
through them by complex nets of interconnected pores might be common. As the circulation of water favors
diagenetic transformations that involve geochemical and isotopic changes, the characterization of flow patterns
is key for outlining areas that are susceptible to such modifications, which is critical to paleoclimatic
studies that are based on speleothems because geochemical and stable isotopic data are used as paleoenvironmental
proxies and absolute ages are obtained by using radioactive isotope ratios. These potential modifications
also have obvious implications for studies based on fluid inclusions in speleothems.
The integrated methodology, which uses primarily non-destructive techniques, shows a high potential for
characterization of any type of speleothem and other continental carbonates such as tufas or sinters.


Item Type:Article
Uncontrolled Keywords:Speleothems, Diagenesis, Porosity, Hydric properties, Paleoclimate
Subjects:Sciences > Geology > Petrology
ID Code:20101
Deposited On:22 Feb 2013 12:19
Last Modified:11 Dec 2018 08:42

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