Publication Date:
2021-11-08
Description:
The circulation of carbon in Earth’s interior occurs through the formation, migration, and ascent of CO2‐
bearing magmas throughout the convective mantle. Their chemical composition spans from carbonatitic to
kimberlitic as a result of either temperature and pressure variations or local redox conditions at which partial
melting of carbonated mantle mineral assemblages occurs. Previous experiments that focused on melting relations
of synthetic CO2‐bearing mantle assemblages revealed the stability of carbonate‐silicate melts, or transitional
melts, that have been generally described to mark the chemical evolution from kimberlitic to carbonatitic
melts at mantle conditions. The migration of these melts upward will depend on their rheology as a function of
pressure and temperature. In this study, we determined the viscosity of carbonate‐silicate liquids (~18 wt% SiO2
and 22.54 wt% CO2) using the falling‐sphere technique combined with in situ synchrotron X‐ray radiography.
We performed six successful experiments at pressures between 2.4 and 5.3 GPa and temperature between 1565 °C
and 2155 °C. At these conditions, the viscosity of transitional melts is between 0.02 and 0.08 Pa˙s; that is, about
one order of magnitude higher than what was determined for synthetic carbonatitic melts at similar P‐T conditions,
likely due to the polymerizing effect of the SiO2 component in the melt.
Description:
Published
Description:
223-236
Description:
1T. Struttura della Terra
Description:
3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
Keywords:
magma, viscosity, redox, carbonate
;
04.01. Earth Interior
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
book chapter
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