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Supercooled interfacial water in fine-grained soils probed by dielectric spectroscopy

Lorek, Andreas and Wagner, N. (2013) Supercooled interfacial water in fine-grained soils probed by dielectric spectroscopy. The Cryosphere, 7 (6), pp. 1839-1855. Copernicus Publications. DOI: 10.5194/tc-7-1839-2013 ISSN 1994-0416

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Official URL: http://www.the-cryosphere.net/7/1839/2013/tc-7-1839-2013.html

Abstract

Water substantially affects nearly all physical, chemical and biological processes on the Earth. Recent Mars observations as well as laboratory investigations suggest that water is a key factor of current physical and chemical processes on the Martian surface, e.g. rheological phenomena. Therefore it is of particular interest to get information about the liquid-like state of water on Martian analogue soils for temperatures below 0 °C. To this end, a parallel plate capacitor has been developed to obtain isothermal dielectric spectra of fine-grained soils in the frequency range from 10 Hz to 1.1 MHz at Martian-like temperatures down to −70 °C. Two Martian analogue soils have been investigated: a Ca-bentonite (specific surface of 237 m2 g−1, up to 9.4% w / w gravimetric water content) and JSC Mars 1, a volcanic ash (specific surface of 146 m2 g−1, up to 7.4% w / w). Three soil-specific relaxation processes are observed in the investigated frequency–temperature range: two weak high-frequency processes (bound or hydrated water as well as ice) and a strong low-frequency process due to counter-ion relaxation and the Maxwell–Wagner effect. To characterize the dielectric relaxation behaviour, a generalized fractional dielectric relaxation model was applied assuming three active relaxation processes with relaxation time of the ith process modelled with an Eyring equation. The real part of effective complex soil permittivity at 350 kHz was used to determine ice and liquid-like water content by means of the Birchak or CRIM equation. There are evidence that bentonite down to −70 °C has a liquid-like water content of 1.17 monolayers and JSC Mars 1 a liquid-like water content of 1.96 monolayers.

Item URL in elib:https://elib.dlr.de/86471/
Document Type:Article
Title:Supercooled interfacial water in fine-grained soils probed by dielectric spectroscopy
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Lorek, AndreasAndreas.Lorek (at) dlr.dehttps://orcid.org/0000-0002-8960-6214
Wagner, N.Institute of Material Research and Testing at the Bauhaus-University WeimarUNSPECIFIED
Date:2013
Journal or Publication Title:The Cryosphere
Refereed publication:Yes
Open Access:Yes
Gold Open Access:Yes
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:7
DOI :10.5194/tc-7-1839-2013
Page Range:pp. 1839-1855
Publisher:Copernicus Publications
ISSN:1994-0416
Status:Published
Keywords:initerfacial water, liquid-like water, Mars, dielectric spectroscopy, ice, permittivity, JSC Mars 1, Bentonite, Birchak, CRIM, plate capacitor, monolayer, Hamaker constant, soil
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Science and Exploration
DLR - Research area:Raumfahrt
DLR - Program:R EW - Erforschung des Weltraums
DLR - Research theme (Project):R - Vorhaben Exploration des Sonnensystems
Location: Berlin-Adlershof
Institutes and Institutions:Institute of Planetary Research > Experimentelle Planetenphysik
Deposited By: Lorek, Dr.rer.nat. Andreas
Deposited On:11 Dec 2013 13:38
Last Modified:09 Jan 2019 12:23

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