T109 Past and Present Biosignature Recognition on Earth, Mars, and Beyond

Monday, 26 September 2016
8:00 AM - 12:00 PM
Mile High Ballroom 2C

THE INFLUENCE OF TEMPERATURE ON MICROBIAL COLONIZATION, CRATERS OF THE MOON NATIONAL MONUMENT, IDAHO: IMPLICATIONS FOR BIOSIGNATURE FORMATION WITHIN “SPECIAL REGIONS” ON MARS

Paper number: T109-1
Program: Technical Sessions
Time: 8:00 AM – 8:15 AM

Authors

Abstract

Lava caves identified on Mars have been designated as Special Regions because they may have acted as biological refugia as surface conditions became less hospitable and therefore may be “the best locations for the search for biosignatures” (Léveillé and Datta, 2010). Lava caves act as water conduits and insulating environments, allowing clement conditions to persist for extended time periods that may be significantly different than surficial conditions. However, Léveillé and Datta (2010) noted “a systematic study of basaltic caves in different climates is required... to elucidate the geomicrobiology and geochemistry... and cave mineral deposits” in order to develop robust geochemical and mineral biosignatures for lava caves.

Our pilot study will systematically link microtextures and mineralogy with microbial processes under three cave climate regimes (1) water:rock, (2) water/ice:rock, and (3) ice:rock systems all within a 1.6 km area at Craters of the Moon National Monument (CROM). Aqueous samples collected from the caves indicate cave waters may derive from a similar source, based on similarities in Cl- (1.6-1.8 mg L-1) and SO42-(2.1-3.8 mg L-1), however, temperatures vary from 10oC (water:rock) to 0oC (ice:rock) conditions. Using a combination of scanning electron microscopy, X-ray diffraction, ICP-OES, and ion chromatography we will (1) quantify microbial colonization and (2) determine textures, and products of chemical and microbial weathering in lava caves experiencing differing water/ice:rock interactions.

CROM is an excellent analog for Mars because (1) the basalts are geochemically similar in major and trace elements and (2) the field site is classified as a cold, semi-arid region, similar to conditions that may have existed on Mars in the late-Noachian to present. Results from this study will aid in the definition of chemical and microbial biosignatures formed under different lava cave climate conditions and in turn aid in our assessment of Mars’s habitability.

Geological Society of America Abstracts with Programs. Vol. 48, No. 7

doi: 10.1130/abs/2016AM-283034

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