Fluid-Assisted Metasomatic Processes On Planetary Bodies: Evidence From Vestan LithologiesOPEN ACCESS 

· by · in , , ,

T. Shisseh, H. Chennaoui Aoudjehane, J.A. Barrat, B. Zanda, R.H. Hewins, C. Agee, L. Folco, E. Jacquet, S. Pont

Geochimica et Cosmochimica Acta
In Press, Journal Pre-proof, Available online 12 November 2022

LINK (OPEN ACCESS)

“The mechanisms responsible for the formation of Fe-rich, metasomatic features in eucrites and their debris in howardites are yet controversial. In this study, secondary phases found in polymict eucrite NWA (Northwest Africa) 11911, howardite NWA 1664, monomict eucrite NWA 8675 and unbrecciated basaltic eucrite NWA 13269 were investigated to elucidate their origin and history of formation. Among them, NWA 11911 is the only rock that displays widespread Fe-enrichment near fractures in unequilibrated and slightly equilibrated basaltic clasts and pyroxene fragments. Fayalitic olivine veinlets with various textures, thicknesses and compositions (Fa64-82) are detected in unequilibrated pyroxenes in NWA 11911, NWA 1664 and NWA 8675. Neighbouring Fe-enriched pyroxene is also Al-depleted compared to magmatic pyroxene (Al2O3 = ∼ 0.3 wt%). NWA 13269 contains Ca-rich plagioclase (An97-98) veinlets associated with Cr-spinel, but apparently no Fe-enrichment in pyroxene nor ferroan olivine despite a careful search. Olivine veinlets have been also detected in equilibrated pyroxene in NWA 11911. Our observations support the fluid-assisted metasomatism scenario that involves the circulation of hydrothermal fluids throughout the fractures of eucritic material.”

Related posts (automatically generated):

  1. Compositional variations in the Vestan Rheasilvia basine
  2. The formation and alteration history of a forsterite-bearing Type C CAI from Allende: Evidence for a Type B CAI precursor, and implications for fluid-assisted metasomatism on the CV chondrite parent body
  3. Geochemistry and petrology of howardite Miller Range 11100: A lithologically diverse piece of the Vestan regolith
  4. Fayalite formation through hydrothermal experiments: Insights into early fluid-assisted aqueous alteration processes on asteroids
  5. Formation Mechanism of Iron-Rich Olivine: Experimental Constrains into Early Fluid-Assisted Hydration and Dehydration Processes on Asteroids
  6. Mineralogy of Marcia, the youngest large crater of Vesta: Character and distribution of pyroxenes and hydrated material
  7. Vestoids, Part II: The basaltic nature and HED meteorite analogs for eight Vp-type asteroids and their associations with (4) Vesta
  8. Non-Vestoid candidate asteroids in the inner main beltOPEN ACCESS 
  9. Temperature constraints by Raman spectroscopy of organic matter in volatile-rich clasts and carbonaceous chondrites
  10. Significant depletion of volatile elements in the mantle of asteroid Vesta due to core formation
Tags: , , , , , , ,