Engineering topics

Domanik, K. J.

Publications and source records attributed to Domanik, K. J..

6 records

NASA NTRS2005

Olivine and Ca-Phosphate in the Diogenites Manegaon and Roda

The textural relationships between the different primary minerals in igneous rocks provide one of the most fundamental pieces of evidence available for inferring the crystallization history of their parent magmas. Unfortunately, the high degree of brecciation that characterizes most diogenites, along with the low modal abundance and small grain sizes of minerals other than orthopyroxene, combine to make identifying and interpreting such textural relationships extremely difficult in this class of meteorites. A few descriptions of primary igneous contacts between orthopyroxene and chromite, troilite, and to a lesser extent, olivine in diogenites have been provided in the literature. In addition to these, in previous work, our research group has characterized several types of igneous contacts between Ca-pyroxene, plagioclase and orthopyroxene in the Bilanga diogenite. We have also described primary igneous inclusions of troilite + kamacite + chromite + Ca-pyroxene +/- Ca-phosphate in orthopyroxene (i.e. Metal/Troilite- Ball inclusions) in the diogenites Bilanga, Manegaon, Johnstown, Roda, Shalka, and Tatahouine. However, for the most part, detailed data on igneous textural relations between minerals other than orthopyroxene in diogenites are still sparse. Of the diogenite samples that we have examined,

Domanik, K. J.↗

NASA NTRS2005

NWA 2736: An Unusual New Graphite-bearing Aubrite

Aubrites are enstatite-rich achondrites that are probably related to enstatite chondrite parent bodies. The exact link, if any, is not understood. They may have formed from melting within one or more enstatite chondrite parent bodies. Description of NWA 2736: One complete stone weighing 171.51 grams was recovered from the Sahara Desert by nomads sometime before September 2004. It was completely covered with fusion crust and desert varnish. This stone is severely weathered, with caramel brown coloration throughout and calcite veins that extend into the interior of the sample. Mineral analyses were performed and elemental x-ray maps were obtained with a CAMECA SX-50 electron microprobe at the Lunar and Planetary Laboratory at the University of Arizona. The relatively high modal abundance of albitic plagioclase, presence of euhedral graphite, depletion of troilite, and occurrence of pervasive kamacite veins (some with daubreelite) all indicate that NWA 2736 has a complex history and may sample a new region of the aubrite parent body. A discussion and analysis on the overall texture of NWA 2736 is presented.

Lowe, J. J.↗

NASA NTRS2004

Early and Late Stage Metals and Sulfides in Diogenites

Diogenites are typically highly brecciated orthopyroxenites that contain 84-100 vol.% orthopyroxene. Common accessory minerals include olivine, chromite, Ca-pyroxene, plagioclase, silica, troilite and Fe-Ni metal. Metal and sulfides are minor phases in diogenites with an average abundance of < 1 vol.% and 0-2 vol.% respectively. However their presence is important, as they could provide information on T-fO2-fS2 conditions and the evolution of the diogenite parent magma during crystallization and/or later metamorphism. We have examined the occurrence of Fe-Ni metal and sulfides in thin sections of several diogenites including, Johnstown, Manegaon, Roda, Shalka, Bilanga, and Tatahouine using optical microscopy and the electron microprobe. Here, we describe three features of metals and sulfides that are common in most of these diogenites. These are: i) The widespread occurrence of pentlandite associated with copper and copper sulfide minerals; ii) Textural evidence that at least some of the metal and sulfide occurring interstitially between, and as inclusions within, orthopyroxene formed from an early immiscible sulfide-oxide liquid; iii) That this sulfide- oxide liquid subsequently fractionated into assemblages containing either Fe-Ni metal, troilite, and chromite or pentlandite, troilite, and copper-bearing sulfide.

Sideras, L. C.↗

NASA NTRS2003

Trace Elements in High-Ca Pyroxene and Plagioclase in the Bilanga Diogenite: Implications for the Magmatic Evolution of Diogenites

High-Ca pyroxene and plagioclase are typically present as minor phases in diogenites. However, although the trace element content of diogenite orthopyroxene has been measured in a number of studies; almost no trace element data is available for the high-Ca pyroxene and plagioclase with which it routinely coexists in these meteorites. These data could provide insights into the nature and evolution of the melts from which diogenites crystallized in the HED parent body. In this study we have obtained initial measurements of several REEs in high-Ca pyroxene, plagioclase, and orthopyroxene in the Bilanga. Measurement of additional incompatible trace element concentrations in these phases is currently in progress.

Domanik, K. J.↗

NASA NTRS2002

Petrology of Antarctic Eucrites PCA 91078 and PCA 91245

Antarctic eucrites PCA 91078 and PCA 91245, are petrographically characterized and found to be unpaired, type 6, basaltic eucrites. Observed textures that provide insight into the petrogenesis of these meteorites are also discussed. Additional information is contained in the original extended abstract.

Howard, L. M.↗

NASA NTRS2002

Bilanga: A Unique Diogenite

The Bilanga diogenite is petrographically examined and found to contain diopside and plagioclase aggregates up to several 100 microns in size. Small scale, original igneous contacts between these phase are often preserved despite brecciation. Additional information is contained in the original extended abstract.

Kolar, S. E.↗