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Laul, J.-C.

Publications and source records attributed to Laul, J.-C..

2 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

The Bholghati (howardite) consortium - An overview

The Bholghati (howardite) has had a complex history. The consortium studies indicate that eucrite clasts show evidence of rapid crystallization followed by prolonged subsolidus annealing. Dark clasts are carbonaceous CM2 type. Bholghati bulk composition can be modeled by 55 percent eucritic, 45 percent diogenitic, and 3 percent dark clast components. The eucritic clasts show a LREE depleted pattern relative to HREEs, which is not typical of a normal eucrite. The LREE depletion requires two-stage melting from a chondritic source. The Bholghati evolution scenario is (1) early multiple magmatic events (4.53 Ga ago), producing eucrites and diogenites; (2) a metamorphic event (2-3 Ga ago) and prolonged subsolidus annealing; (3) fragmentation and low-temperature mixing of eucrites and diogenites; (4) low-velocity impact and admixing of carbonaceous material; (5) disruption of regolith and ejection of Bholghati 10-17 Ma ago; and (6) Bholghati fell on the earth in 1905.

Laul, J.-C.↗
NASA NTRS1990

The Bholghati howardite - Chemical study

Bholghati is homogeneous on a cm scale in major element composition, but heterogeneous in trace elements such as the rare earth elements (REEs). The REEs are concentrated in accessory phosphates, and their sampling can influence the REE patterns of eucritic clasts which, in turn, can govern the bulk REE patterns. Bholghati can be reasonably modeled with 56 percent eucritic, 45 percent diogenitic, and 3 percent dark clast components; however, an additional component (feldspathic) is required to match the bulk composition. Dark clasts represent carbonaceous CM type material that was admixed with other components during regolith formation on the eucrite parent body. One eucritic clast (fine-grained) is light REE (LREE) depleted relative to heavy REE, which is unusual in normal eucrites. The LREE depletion pattern cannot be modeled from one-stage partial melting of a chondritic source; however, it can be modeled from a nonchondritic source depleted in LREEs or multistage melting of a chondritic source, provided that the LREE depletion is not from undersampling of phsphates. Bholghati has a complex history that involved early multiple magmatic events, later annealing, and fragmentation and low-temperature mixing of eucritic, diogenitic, and carbonaceous components on the howardite parent body.

Laul, J.-C.↗