TY - JOUR
T1 - Thermal emission spectra of terrestrial alkaline volcanic rocks
T2 - Applications to Martian remote sensing
AU - Dunn, Tasha L.
AU - McSween, Harry Y.
AU - Christensen, Philip
N1 - Funding Information:
Rita Ribeiro is a student of the Ph.D. Program in Pharmaceutical Sciences from the Faculty of Pharmacy, University of Coimbra, and a recipient of the fellowship SFRH/BD/ 121935/2016 from the Portuguese Foundation for Science and Technology. This work was funded by Portuguese National funds via FCT ? Funda??o para a Ci?ncia e a Tecnologia, I.P. ? under projects Cancel Stem (reference POCI-01-0145-FEDER-016390), CENTRO-01-0145-FEDER-000012 (HealthyAging2020), Euronanomed2 (FCT reference ENMed/0005/2015), and CNC. IBILI (FCT reference UID/NEU/04539/2019).
Funding Information:
Acknowledgments Rita Ribeiro is a student of the Ph.D. Program in Pharmaceutical Sciences from the Faculty of Pharmacy, University of Coimbra, and a recipient of the fellowship SFRH/BD/ 121935/2016 from the Portuguese Foundation for Science and Technology. This work was funded by Portuguese National funds via FCT – Fundação para a Ciência e a Tecnologia, I.P. – under projects Cancel Stem (reference POCI-01-0145-FEDER-016390), CENTRO-01-0145-FEDER-000012 (HealthyAging2020), Euronanomed2 (FCT reference ENMed/0005/2015), and CNC. IBILI (FCT reference UID/NEU/04539/2019).
PY - 2007/5/20
Y1 - 2007/5/20
N2 - The long-standing assessment that Martian igneous compositions are strictly subalkaline has recently been brought into question by the detection of alkaline rocks at Gusev crater. In this study, we assess the utility of thermal emission spectra (5-25 μm at 10 cm-1 spectral sampling) in identifying and classifying terrestrial alkalic volcanic rocks, and then apply our results to MGS/ TES data. Using spectral linear deconvolution, we determined modal mineralogies of a suite of alkaline rocks (basalts, trachyandesites, trachytes, rhyolites). We then compared modeled data to modes measured using an electron microprobe mapping technique. Most phases modeled well (within 10 vol%). Modeled plagioclase abundances, however, were too high, reflecting the presence of devitrified glass and the absence of appropriate glass end-members in the spectral library. Systematic inaccuracies in bulk-rock chemistries, derived by combining modeled mineral end-member compositions in proportion to their abundances, reflect the overdetermination of plagioclase and resulting mass balance problems. Nevertheless, modeled mineralogies and derived bulk-rock chemistries clearly reveal the alkaline character of these rocks, and many rocks are correctly classified petrologically. To determine if alkaline rocks can be detected in global and regional TES spectra, we deconvolved ST1, ST2, and four compositionally distinct regional spectral classes using our end-member library. Our results suggest that alkaline rocks are not readily detected in most regionally- and globally-derived TES spectra. We do not rule out the possibility that areas of regional-scale alkalic volcanism exist, although they are more likely to be identified by in situ surface investigations.
AB - The long-standing assessment that Martian igneous compositions are strictly subalkaline has recently been brought into question by the detection of alkaline rocks at Gusev crater. In this study, we assess the utility of thermal emission spectra (5-25 μm at 10 cm-1 spectral sampling) in identifying and classifying terrestrial alkalic volcanic rocks, and then apply our results to MGS/ TES data. Using spectral linear deconvolution, we determined modal mineralogies of a suite of alkaline rocks (basalts, trachyandesites, trachytes, rhyolites). We then compared modeled data to modes measured using an electron microprobe mapping technique. Most phases modeled well (within 10 vol%). Modeled plagioclase abundances, however, were too high, reflecting the presence of devitrified glass and the absence of appropriate glass end-members in the spectral library. Systematic inaccuracies in bulk-rock chemistries, derived by combining modeled mineral end-member compositions in proportion to their abundances, reflect the overdetermination of plagioclase and resulting mass balance problems. Nevertheless, modeled mineralogies and derived bulk-rock chemistries clearly reveal the alkaline character of these rocks, and many rocks are correctly classified petrologically. To determine if alkaline rocks can be detected in global and regional TES spectra, we deconvolved ST1, ST2, and four compositionally distinct regional spectral classes using our end-member library. Our results suggest that alkaline rocks are not readily detected in most regionally- and globally-derived TES spectra. We do not rule out the possibility that areas of regional-scale alkalic volcanism exist, although they are more likely to be identified by in situ surface investigations.
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U2 - 10.1029/2006JE002766
DO - 10.1029/2006JE002766
M3 - Article
AN - SCOPUS:34447302010
SN - 0148-0227
VL - 112
JO - Journal of Geophysical Research: Planets
JF - Journal of Geophysical Research: Planets
IS - 5
M1 - E05001
ER -