Alkaline volcanic rocks from the Columbia Hills, Gusev crater, Mars

H. Y. McSween, Steven Ruff, R. V. Morris, James Bell, K. Herkenhoff, R. Gellert, K. R. Stockstill, L. L. Tornabene, S. W. Squyres, J. A. Crisp, Philip Christensen, T. J. McCoy, D. W. Mittlefehldt, M. Schmidt

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Abstract

Irvine, Backstay, and Wishstone are the type specimens for three classes of fine-grained or fragmental, relatively unaltered rocks with distinctive thermal emission spectra, found as float on the flanks of the Columbia Hills. Chemical analyses indicate that these rocks are mildly alkaline basalt, trachybasalt, and tephrite, respectively. Their mineralogy consists of Na- and K-rich feldspar(s), low- and high-Ca pyroxenes, ferroan olivine, Fe-Ti (and possibly Cr) oxides, phosphate, and possibly glass. The texture of Wishstone is consistent with a pyroclastic origin, whereas Irvine and Backstay are lavas or possibly dike rocks. Chemical compositions of these rocks plot on or near liquid lines of descent for most elements calculated for Adirondack class rocks (olivine-rich basalts from the Gusev plains) at various pressures from 0.1 to 1.0 GPa. We infer that Wishstone-, Backstay-, and Irvine-class magmas may have formed by fractionation of primitive, oxidized basaltic magma similar to Adirondack-class rocks. The compositions of all these rocks reveal that the Gusev magmatic province is alkaline, distinct from the subalkaline volcanic rocks thought to dominate most of the planet's surface. The fact that differentiated volcanic rocks were not encountered on the plains prior to ascending Husband Hill may suggest a local magma source for volcanism beneath Gusev crater.

Original languageEnglish (US)
Article numberE09S91
JournalJournal of Geophysical Research E: Planets
Volume111
Issue number9
DOIs
StatePublished - Sep 20 2006

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ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

Cite this

McSween, H. Y., Ruff, S., Morris, R. V., Bell, J., Herkenhoff, K., Gellert, R., Stockstill, K. R., Tornabene, L. L., Squyres, S. W., Crisp, J. A., Christensen, P., McCoy, T. J., Mittlefehldt, D. W., & Schmidt, M. (2006). Alkaline volcanic rocks from the Columbia Hills, Gusev crater, Mars. Journal of Geophysical Research E: Planets, 111(9), [E09S91]. https://doi.org/10.1029/2006JE002698