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2013

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Full-Text Articles in Physical Sciences and Mathematics

Phanerozoic Surface History Of The Slavecraton, Alexis K. Ault, Rebecca M. Flowers, Samuel A. Bowring Sep 2013

Phanerozoic Surface History Of The Slavecraton, Alexis K. Ault, Rebecca M. Flowers, Samuel A. Bowring

Geosciences Faculty Publications

New apatite (U-Th)/He (AHe) thermochronometry data and key geologic constraints from Slave craton kimberlites are used to develop a model for the Phanerozoic burial, unroofing, and hypsometric history of the northwestern Canadian shield. AHe dates range from 210 ± 13 to 382 ± 79 Ma, are older in the eastern Slave craton and decrease westward, and resolve the spatial extent, thickness, and history of now-denuded sedimentary units. Results indicate Paleozoic heating to temperatures ≥85–90°C, suggesting regional burial beneath ≥2.8 km of strata while the region was at sea level, followed by the westward migration of unroofing across the craton. This …

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Mid-Ir Emissivity Spectra Of Mg- And Ca- Carbonates, Oxides, And Hydroxides, Timothy Glotch Jan 2013

Mid-Ir Emissivity Spectra Of Mg- And Ca- Carbonates, Oxides, And Hydroxides, Timothy Glotch

Geosciences Research Data

We used three methods—spectral index mapping, linear spectral mixture analysis, and factor analysis and target transformation—to determine if carbonate decomposition products, including lime (CaO), periclase (MgO), portlandite (Ca(OH)2), and brucite (Mg(OH)2), are present on the surface of Mars. Using an expanded spectral library that includes decomposition products of calcite and magnesite, we deconvolved a binned emissivity data set from the Mars Global Surveyor Thermal Emission Spectrometer (MGS-TES). The deconvolution model indicates that anhydrous carbonates are not present at kilometer scales above the TES detection limit; however, carbonate decomposition products may be present at or above the TES detection limit in …

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