Chemical and petrological study of igneous lithic clasts from the Kapoeta howardite

Thesis/Dissertation · Sat Jan 01 00:00:00 EST 1983

OSTI ID:5948702

Smith, M R

Instrumental and radiochemical neutron activation analyses supported by electron microprobe mineral analyses and petrographic observations are presented for approximately forty individual clasts separated from the Kapoeta howardite. These clasts are classified into eucritic, cumulate-like, mafic (plagioclase +- olivine-bearing pyroxenites), pyroxenite, polymict and/or metal-rich and chondritic components. Geochemical inferences are presented which suggest significant compositional variations in the eucritic clasts as compared to normal main group eucrites. Conclusions are presented which attempt to account for the compositional variations observed in normal eucrites, diogenites, pallasites and the howardite lithic clasts observed in this work. The evolutionary sequence includes: (1) initial production of extensive core melts leaving pallasitic-like residuals; (2) generation of near surface low-degree partial melts (Mg-rich eucritic clasts); (3) crystallization of extruded primary melts (diogenites and cumulate eucrites); and (4) cumulate remelting (normal eucrites) episodes. This sequence of igneous events requires that the KPB was heated by a melt-mobile heat source such as primordial /sup 26/Al.

• Research Organization: Oregon State Univ., Corvallis (USA)
• OSTI ID: 5948702
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
IGNEOUS ROCKS
ACTIVATION ANALYSIS
PETROLOGY
CHEMICAL COMPOSITION
NEUTRON REACTIONS
BARYON REACTIONS
CHEMICAL ANALYSIS
GEOLOGY
HADRON REACTIONS
NUCLEAR REACTIONS
NUCLEON REACTIONS
ROCKS
580100* - Geology & Hydrology- (-1989)
400101 - Activation
Nuclear Reaction
Radiometric & Radiochemical Procedures