TY - JOUR

T1 - Raman Spectroscopy of High-Pressure Phases in Shocked L6 Chondrite NWA 5011

AU - Litasov, K. D.

AU - Badyukov, D. D.

N1 - Publisher Copyright: © 2019, Pleiades Publishing, Ltd.

PY - 2019/8/1

Y1 - 2019/8/1

N2 - Abstract—The paper presents the results of studies of thick shock melt veins in the L6 chondrite NWA 5011. The veins contain a wide variety of high-pressure phases that correspond to contrast values of pressure–temperature parameters on equilibrium phase diagrams. Olivine was transformed to ringwoodite and wadsleyite, orthopyroxene to majorite, akimotoite, and bridgmanite glass, maskelynite is converted to jadeite (+SiO2) and lingunite, apatite to tuite, and chromite to the phase with the calcium ferrite (mCF-FeCr2O4) structure. The peak PT shock parameters for NWA 5011 seem to be the highest among the ones for other shocked chondrites according to the wide occurrence of lingunite and bridgmanite glass and are considerably higher than 25 GPa and 2500 K. Akimotoite crystals in a quenched matrix of the shock melt veins were found for the first time. Probably, they initially crystallized as bridgmanite, since akimotoite is not a liquidus phase in the related systems. Plagioclase–chromite aggregates have been established, which characterize the late stages of the shock process and are formed during successive crystallization from isolated pockets of the impact melt.

AB - Abstract—The paper presents the results of studies of thick shock melt veins in the L6 chondrite NWA 5011. The veins contain a wide variety of high-pressure phases that correspond to contrast values of pressure–temperature parameters on equilibrium phase diagrams. Olivine was transformed to ringwoodite and wadsleyite, orthopyroxene to majorite, akimotoite, and bridgmanite glass, maskelynite is converted to jadeite (+SiO2) and lingunite, apatite to tuite, and chromite to the phase with the calcium ferrite (mCF-FeCr2O4) structure. The peak PT shock parameters for NWA 5011 seem to be the highest among the ones for other shocked chondrites according to the wide occurrence of lingunite and bridgmanite glass and are considerably higher than 25 GPa and 2500 K. Akimotoite crystals in a quenched matrix of the shock melt veins were found for the first time. Probably, they initially crystallized as bridgmanite, since akimotoite is not a liquidus phase in the related systems. Plagioclase–chromite aggregates have been established, which characterize the late stages of the shock process and are formed during successive crystallization from isolated pockets of the impact melt.

KW - akimotoite

KW - bridgmanite

KW - chondrite

KW - majorite

KW - meteorite

KW - ringwoodite

KW - shock metamorphism

KW - SYSTEM

KW - MINERALS

KW - STABILITY

KW - ASSEMBLAGES

KW - STISHOVITE

KW - PERIDOTITE

KW - DISCOVERY

KW - CONSTRAINTS

KW - 22 GPA

KW - TRANSITIONS

UR - http://www.scopus.com/inward/record.url?scp=85070237523&partnerID=8YFLogxK

U2 - 10.1134/S001670291908007X

DO - 10.1134/S001670291908007X

M3 - Article

AN - SCOPUS:85070237523

VL - 57

SP - 912

EP - 922

JO - Geochemistry International

JF - Geochemistry International

SN - 0016-7029

IS - 8

ER -