On Developing an Electrochemistry-Based Geochemical Framework in
Planetary Minerals Using in-situ Electrical Spectroscopy
Abstract
NASA’s future missions will focus on looking for evidence of life under
extreme environments, such as cold arid planets (Mars) and icy moons
(Eurpoa). There is particular interest in studying localized
geo-chemical systems that host gradients with the potential for
harboring evidence of past or present life. Such gradient-driven systems
include, for example, layering of minerals of varying oxidation states
in the Martian subsurface or in Earth’s seafloor sediments; chemical
precipitates separating fluids of different pH or Eh such as in a
hydrothermal vent; or radiation-induced oxidant production in planetary
ices. A challenge is that these simulated precipitates are redox
sensitive and evolve over a relatively short lifetime (1-4 hrs)
necessitating viable in-situ, non-destructive analytical techniques.
Promising techniques for such studies are electrochemical methods, which
are particularly suited for characterizing interfaces and chem-ical
gradients. Combined with recent advances in electrochemical instrument
technologies, new methods have been developed toward integrating
portable, electrochemical systems for ex-situ and/or in-situ chemical
characterization. JPL has already made significant progress in
developing these new technologies, particularly electro-chemical
impedance spectroscopies (EIS) for in-situ characterization of
geochemical materials (i.e., soils ice mineralogy, and brines) and even
life detection sensoring. Currently, we are exploring further
appli-cations of electrical spectroscopy techniques in developing an
electrochemistry-based framework using planetary analog systems based on
MRO/CRISM and Cassini/INMS observations in attempts to distin-guish
abiotic vs biotic environments, and with active and inactive containing
organics from electrical properties characterization. We will highlight
some of our group’s successes and preliminary results of geochemical
experimentation using various electrochemical techniques.