Presenter Information

Andrew Agent, SUNY GeneseoFollow

Submission Type

Poster

Start Date

April 2021

Abstract

Before NASA sent the Pathfinder lander and Sojourner rover to the mouth of Ares Vallis in 1997, they anticipated the discovery of Hesperian-age (3.6 Ga-3.0 Ga) sediments deposited from catastrophic outflows. When pictures came back, the rocks they discovered were large, boulder-size, angular, and were largely inconsistent with transport by large floods. The origin of the deposits at the Pathfinder landing site remains controversial. This study aims to constrain the surface geology of the Pathfinder landing site using new high-resolution imagery and crater statistics. Context Camera (CTX) images along with High-Resolution Imaging Experiment (HiRISE) images were used to map surface geology. Mars Orbiter Laser Altimeter (MOLA) elevation raster and Night Thermal Emission Imaging System (THEMIS) imagery were used. Multiple smooth terrains, at varying elevations, were identified in the region. Preserved geomorphic terraces, grooves, and streamlined islands from floods were also noted. Crater counts on all surfaces indicate early to late Hesperian model ages for craters with diameters (D) > 500 m, consistent with the timing of flooding in Ares Vallis. However, a resurfacing event occurred across all units, regardless of elevation, in the mid-Amazonian at ~950 Ma. This resurfacing likely had a large influence on the geology of the Pathfinder landing site and may have been caused by ~100 m of burial or erosion post-flooding.

Comments

Sponsored by Nicholas Warner

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Apr 26th, 12:00 AM

205— Revisiting the Geologic History of the Pathfinder Landing Site at Ares Vallis, Mars

Before NASA sent the Pathfinder lander and Sojourner rover to the mouth of Ares Vallis in 1997, they anticipated the discovery of Hesperian-age (3.6 Ga-3.0 Ga) sediments deposited from catastrophic outflows. When pictures came back, the rocks they discovered were large, boulder-size, angular, and were largely inconsistent with transport by large floods. The origin of the deposits at the Pathfinder landing site remains controversial. This study aims to constrain the surface geology of the Pathfinder landing site using new high-resolution imagery and crater statistics. Context Camera (CTX) images along with High-Resolution Imaging Experiment (HiRISE) images were used to map surface geology. Mars Orbiter Laser Altimeter (MOLA) elevation raster and Night Thermal Emission Imaging System (THEMIS) imagery were used. Multiple smooth terrains, at varying elevations, were identified in the region. Preserved geomorphic terraces, grooves, and streamlined islands from floods were also noted. Crater counts on all surfaces indicate early to late Hesperian model ages for craters with diameters (D) > 500 m, consistent with the timing of flooding in Ares Vallis. However, a resurfacing event occurred across all units, regardless of elevation, in the mid-Amazonian at ~950 Ma. This resurfacing likely had a large influence on the geology of the Pathfinder landing site and may have been caused by ~100 m of burial or erosion post-flooding.

 

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