Collinet, M.

Médard, E.

Charlier, Bernard

Vander Auwera, Jacqueline

Grove, T.L.

We have performed piston-cylinder experiments on a primitive martian mantle composition between 0.5 and 2.2 GPa and 1160 to 1550 °C. The composition of melts and residual minerals constrain the possible melting processes on Mars at 50 to 200 km depth under nominally anhydrous conditions. Silicate melts produced by low degrees of melting (2 (43.7-59.0 wt.%), MgO (5.3-18.6 wt.%) and Na2O + K2O (1.0-6.5 wt.%) contents. We provide a new equation to estimate the solidus temperature of the martian mantle: T(°C)=1033+168.1P(GPa)-14.22P2(GPa), which places the solidus 50 °C below that of fertile terrestrial peridotites. Low- and high-degree melts are compared to martian alkaline rocks and basalts, respectively. We suggest that the parental melt of Adirondack-class basalts was produced by ~25 wt.% melting of the primitive martian mantle at 1.5 GPa (~135 km) and ~1400 °C. Despite its brecciated nature, NWA 7034/7533 might be composed of material that initially crystallized from a primary melt produced by ~10-30 wt.% melting at the same pressure. Other igneous rocks from Mars require mantle reservoirs with different CaO/Al2O3 and FeO/MgO ratios or the action of fractional crystallization. Alkaline rocks can be derived from mantle sources with alkali contents (~0.5 wt.%) similar to the primitive mantle

Collinet, Max

Médard, Etienne

Grove, Timothy L.

Repository of the University of Namur

Melting of the primitive martian mantle at 0.5-2.2 GPa and the origin of basalts and alkaline rocks on Mars

International audienceWe have performed piston–cylinder experiments on a primitive martian mantle composition between 0.5 and 2.2 GPa and 1160 to 1550 °C. The composition of melts and residual minerals constrain the possible melting processes on Mars at 50 to 200 km depth under nominally anhydrous conditions. Silicate melts produced by low degrees of melting (<10 wt.%) were analyzed in layers of vitreous carbon spheres or in micro-cracks inside the graphite capsule. The total range of melt fractions investigated extends from 5 to 50 wt.%, and the liquids produced display variable SiO2 (43.7–59.0 wt.%), MgO (5.3–18.6 wt.%) and Na2O + K2O (1.0–6.5 wt.%) contents. We provide a new equation to estimate the solidus temperature of the martian mantle: , which places the solidus 50 °C below that of fertile terrestrial peridotites. Low- and high-degree melts are compared to martian alkaline rocks and basalts, respectively. We suggest that the parental melt of Adirondack-class basalts was produced by ∼25 wt.% melting of the primitive martian mantle at 1.5 GPa (∼135 km) and ∼1400 °C. Despite its brecciated nature, NWA 7034/7533 might be composed of material that initially crystallized from a primary melt produced by ∼10–30 wt.% melting at the same pressure. Other igneous rocks from Mars require mantle reservoirs with different CaO/Al2O3 and FeO/MgO ratios or the action of fractional crystallization. Alkaline rocks can be derived from mantle sources with alkali contents (∼0.5 wt.%) similar to the primitive mantle

Grove, Timothy

HAL: Hyper Article en Ligne

Melting of the primitive martian mantle at 0.5–2.2 GPa and the origin of basalts and alkaline rocks on Mars

HAL-UJM

HAL Clermont Université

Max Collinet

Etienne Médard

Bernard Charlier

Jacqueline Vander Auwera

Timothy L. Grove

Crossref

Earth and Planetary Science Letters

HAL-INSU

Open Repository and Bibliography - Liège

http://orbi.ulg.ac.be/bitstream/2268/185270/1/Collinet%20et%20al%202015%20EPSL.pdf

Melting of the primitive martian mantle at 0.5-2.2 GPa and the origin of basalts and alkaline rocks on Mars

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Repository of the University of Namur

HAL: Hyper Article en Ligne

HAL-UJM

HAL Clermont Université

Crossref

HAL-INSU

Repository of the University of Namur

Open Repository and Bibliography - Liège