Graduate Thesis Or Dissertation
 

A chemical and petrographic study of refractory inclusions from Kaba (CV3) chondrite

Público Deposited

Contenido Descargable

Descargar PDF
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/tm70mx94r

Descriptions

Attribute NameValues
Creator
Abstract
  • Refractory inclusions from Kaba (CV3) chondrite were studied by instrumental neutron activation analysis (INAA) and electron probe microanalysis (EPMA). The inclusions observed cover a wide range of chemical patterns, mineral assemblages and textures, indicating the complexity of early solar nebular conditions. The elemental abundances normalized by Cl chondritic abundances vary smoothly as a function of their volatilities, suggesting these inclusions were formed by condensation/evaporization processes in the primeval solar nebula. The average REE pattern of Group III inclusions has an enrichment of 3lxCl with approximately equal depletions of Eu and Yb (Eu/Eu*=0.33, Yb/Yb*=0.29). Group III inclusions are irregularly-shaped aggregates of rounded or sub-rounded melilite-rich nodules rimmed with mono-mineralic layers of high-Al phase, Ti-Al pyroxene and hedenbergite. KI53 is an irregular aggregate. It shows a strongly fractionated REE pattern, but differs from typical the Allende Group II pattern by exhibiting normal Eu and Yb abundances. KI77 and KI88 inclusions consist of anorthite, diopside and enstatite, with Si-rich phase in fine-grained areas. Their element patterns suggest they were condensed from a gaseous environment rich in moderately volatile elements. The lower enrichment of Al, Ti and Ca is interpreted by the partial vaporization of the inclusion by a transient event in an oxidizing environment near the nebular midplane. This process caused the partial loss of Al, Ti, Ca and more volatile elements. The rim is the resultant vaporization residue. This model combines the modification of refractory elemental pattern and the rim formation in one event. The partial evaporization of a precursor inclusion with an unfractionated REE pattern would form a rim where Yb and Eu are strongly depleted in different degrees, and the interior is not effected. A Group III pattern would be observed to be the summation of two components, rim and interior. The similarities between Kaba and Allende in whole-rock composition and their inclusion mineralogies and textures suggest they were formed in a generally similar nebular region. Kaba inclusions are less altered by secondary reactions with a gas phase at lower temperature, therefore informations of early solar nebular conditions are better preserved.
Resource Type
Fecha Disponible
Fecha de Emisión
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Academic Affiliation
Non-Academic Affiliation
Subject
Declaración de derechos
Publisher
Peer Reviewed
Language
Digitization Specifications
  • File scanned at 300 ppi (Monochrome, 8-bit Grayscale) using ScandAll PRO 1.8.1 on a Fi-6670 in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR.
Replaces

Relaciones

Parents:

This work has no parents.

En Collection:

Elementos

Miniatura Título Fecha de subida Visibilidad Acciones
file details LiuYun-Gang1990.pdf 2017-08-09 Público Descargar