Columbia Hills (Mars)

Columbia Hills (Mars). The Columbia Hills are a range of low hills within the vast Gusev crater on Mars, explored extensively by the Spirit rover during the Mars Exploration Rover mission. Named in memory of the astronauts lost in the Space Shuttle Columbia disaster, these hills became a primary scientific target after the rover's initial plains traverse proved geologically less complex. The hills revealed a diverse and ancient geological history, providing critical evidence for past aqueous environments on the Red Planet.

Overview

Located in the Gusev crater, a site chosen for its potential as an ancient lakebed, the Columbia Hills rise approximately 100 meters above the surrounding plains. The feature was named by NASA in 2004 to honor the crew of the ill-fated STS-107 mission. The Spirit rover began its ascent into the hills in 2004, vastly extending its mission beyond the initial 90-sol plan. This area contrasted sharply with the volcanic plains of the crater floor, offering a window into a more varied and water-influenced past, as hypothesized by scientists from the Jet Propulsion Laboratory and Cornell University.

Geology and composition

The geology of the Columbia Hills is markedly different from the basaltic rocks found on the adjacent Gusev plains. The hills are composed of older, more altered bedrock, with spectral data from instruments like the Mini-TES indicating the presence of olivine, pyroxene, and hematite. Key rock classifications identified by the Spirit rover's APXS and Mössbauer spectrometer include Adirondack class basalts and, more significantly, the Clovis class and Wishstone class rocks, which showed evidence of extensive aqueous alteration. The presence of sulfate minerals and goethite, an iron-bearing mineral that forms in water, was a major discovery pointing to past hydrothermal activity or groundwater interactions.

Exploration by Spirit rover

The Spirit rover arrived at the base of the Columbia Hills in June 2004, after a drive of several kilometers from its landing site. Its exploration was directed by the rover team at the Jet Propulsion Laboratory, with key science operations led by institutions like Cornell University and the University of Arizona. The rover meticulously examined numerous targets, including the notable outcrops Husband Hill, McCool Hill, and Home Plate, using its Instrument Deployment Device (IDD) to perform in-situ measurements. This campaign, which included the rover becoming a stationary science platform after a wheel failure in 2009, provided a multi-year stratigraphic record of the hills' formation.

Scientific findings

Scientific findings from the Columbia Hills revolutionized understanding of Martian history. Data confirmed that the environment was once wet and possibly habitable, with conditions different from the simple evaporation scenario initially envisioned for Gusev crater. The discovery of silica-rich deposits at Home Plate, suggestive of a hydrothermal vent or fumarole environment, provided strong evidence for past hydrothermal systems. Findings of carbonate minerals and the association of specific minerals with altered tuff or breccia were published in major journals like *Science* and presented at conferences such as the Lunar and Planetary Science Conference, significantly advancing the field of astrobiology.

Features and hills within the complex

The Columbia Hills complex contains several distinct features, each named for the STS-107 crew members. The primary peaks include Husband Hill, the highest point, and McCool Hill. Other significant geological formations within the area are Home Plate, a layered, plateau-like structure believed to be an explosive volcanic deposit, and the Tennessee Valley and Larry's Lookout areas. Nearby features examined include Methuselah and Jibsheet outcrops, with the entire complex situated northwest of the Bonneville crater and east of the Apollo 1 Hills.

Category:Surface features of Mars Category:Hills of Mars Category:Gusev crater