The presence of layered carbonate rich rocks near Syrtis Major volcano, in the Nili Fossae region and within the Gusev Crater has been interpreted as an evidence for sedimentary carbonate formation on Noachian Mars. In particular, CRISM spectra indicate the presence of carbonates, a mixture of hydrated Fe-Mg silicates (chlorite, serpentine, pumpellyite and vermiculite) and kaolinite-group minerals in the bedrock exposures located nearby Syrtis Major volcano. The authors have explained the formation of these rocks as the result of metamorphic processes, which acted on interlayered carbonate- and siliciclastic sediments buried under Hesperian age basalts, and were triggered by the heat associated to lava emplacement. Alternatively, the basaltic crust could have been metasomatized by CO2-rich fluids of unknown origin. As an alternative hypothesis to both these scenarios, we suggest the emplacement of igneous carbonates: carbonatites.
THE SEARCH OF CARBONATES ON MARS: VOLCANIC VERSUS SEDIMENTARY ORIGIN
LIBERI, FRANCESCA;POMPILIO, Loredana;MARINANGELI, Lucia;ROSATELLI, Gianluigi;
2013-01-01
Abstract
The presence of layered carbonate rich rocks near Syrtis Major volcano, in the Nili Fossae region and within the Gusev Crater has been interpreted as an evidence for sedimentary carbonate formation on Noachian Mars. In particular, CRISM spectra indicate the presence of carbonates, a mixture of hydrated Fe-Mg silicates (chlorite, serpentine, pumpellyite and vermiculite) and kaolinite-group minerals in the bedrock exposures located nearby Syrtis Major volcano. The authors have explained the formation of these rocks as the result of metamorphic processes, which acted on interlayered carbonate- and siliciclastic sediments buried under Hesperian age basalts, and were triggered by the heat associated to lava emplacement. Alternatively, the basaltic crust could have been metasomatized by CO2-rich fluids of unknown origin. As an alternative hypothesis to both these scenarios, we suggest the emplacement of igneous carbonates: carbonatites.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
