| Title | Secondary Fe and Al in Antarctic paleosols; correlation to Mars with prospect for the presence of life |
| Author | Mahaney, W.C.; Dohm, J.M.; Kapran, B.; Hancock, R.G.V.; Milner, M.W. |
| Author Affil | Mahaney, W.C., Quaternary Surveys, Thornhill, ON, Canada. Other: University of Arizona; McMaster University, Canada; MWM Consulting, Canada |
| Source | Icarus, 203(1), p.320-330. Publisher: Elsevier, New York, NY, United States. ISSN: 0019-1035 |
| Publication Date | Sept. 2009 |
| Notes | In English. 85 refs. GeoRef Acc. No: 300003 |
| Index Terms | Antarctica--McMurdo dry valleys; aluminum; Amazonian; Antarctica; astrobiology; Cenozoic; clastic sediments; clay minerals; ferric iron; ferrihydrite; grain size; ice; iron; Mars; McMurdo dry valleys; metals; microorganisms; middle Miocene; Miocene; moisture; Neogene; Noachian; oxidation; oxides; paleoclimatology; paleosols; pH; planets; polar deserts; secondary minerals; sediments; SEM data; sheet silicates; silicates; terrestrial analogs; terrestrial planets; Tertiary; till; Victoria Land; water; water table; weathering |
| Abstract | Middle-Miocene age paleosols in the Antarctic Dry Valleys were studied for their compositional variation and concentrations of secondary oxides/coatings in ‹2 mm matrix material in tills. The paleosols date to between 10-18 Ma by 10Be, forming prior to and just following the transition from warm- based to cold-based ice, when the climate is thought to have entered a prolonged cold/dry period in which soil moisture would have been frozen most of the year. The progression of release of secondary oxides of Fe and Al shows variable percentages of individual oxihydrites relative to chemical element totals, and thus, to consume total Fe and Al would require tens of millions of additional years. The slow progression of Fed/Fet, used as a measure of relative age in other warmer alpine and Arctic climates, is shown here to amount to ‹15 percent of the total Fe available for weathering. Ferrihydrite variability in paleosols, often used to indicate the presence of fluctuating/perched ground water tables, suggests that liquid water may have accumulated in mid-profile in some instances, perhaps during periods when the climate was somewhat warmer for several weeks during the summer. Variable Fe and Al ratios and arithmetic functions argue for extremely slow but sustainable release of oxides in a cold, polar desert climate, in which temperatures prohibit the formation of clay minerals. (mod. journ. abst.) |
| URL | http://hdl.handle.net/10.1016/j.icarus.2009.05.007 |
| Publication Type | journal article |
| Record ID | 88409 |