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Lipschutz, M. E.

Publications and source records attributed to Lipschutz, M. E..

At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

Petrogenetic relationship between Allan Hills 77005 and other achondrites

The paper presents chemical and petrologic data relating the Allan Hills (ALHA) 77005 achondrite from Antarctica and explores their petrogenetic relationship with the shergottites. Petrologic similarities with the latter in terms of mineralogy, oxidation state, inferred source region composition, and shock ages suggest a genetic relationship, also indicated by volatile to involatile element ratios and abundances of other trace elements. ALHA 77005 may be a cumulate crystallized from a liquid parental to materials from which the shergottites crystallized or a sample of peridotite from which shergottite parent liquids were derived. Chemical similarities with terrestrial ultramafic rocks suggest that it provides an additional sample of the only other solar system body with basalt source origins chemically similar to the upper earth mantle.

Mcsween, H. Y., Jr.↗
NASA NTRS1979

On volatile element trends in gas-rich meteorites

Study of 10 volatile elements (and non-volatile Co) in co-existing light and dark portions of 6 gas-rich chondrites indicates patterns of distinct but non-uniform enrichment of volatile elements. Only Cs is enriched in all samples; Bi and Tl enrichments covary. The observed enrichments are inconsistent with prior suggestions of admixture of C1 or C2 chondritic matter, whether pristine or partly devolatilized, but suggest that both light and dark portions of each chondrite represents a compositionally more extended sampling of parental nebular material than hitherto known.

Bart, G.↗
NASA NTRS1979

Trace element contents of selected antarctic meteorites, 1

Data are reported for volatile/mobile Ag, As, Au, Bi, Cd, Co, Cs, Cu, Ga, In, Rb, Sb, Se, Te, T1 and Zn in exterior and/or interior samples of four Antarctic meteorites: 77005 (unique achondrite); 77257 (unreilite); 77278 (L3); 77299 (H3). Exterior samples reflect contamination and/or leaching by weathering but trace element (ppm-ppt) contents in interior samples seem reasonable for representatives of these rare meteoritic types. The 77005 achondrite seems related to shergottites; other samples extend compositional ranges previously known for their types. With suitable precautions, Antarctic meteorite finds yield trace element data as reliable as those obtained from previously known falls.

Biswas, S.↗
NASA NTRS1979

On mobile element transport in heated Abee

Abee chondrite samples were heated at 700 C for one week at 0.00001 to 0.001 atm Ne or at 0.00001 atm H2. Samples heated in Ne showed greater loss of Bi and Se and greater retention of Zn than those heated in H2. An inverse relationship between Zn retention and ambient Ne pressure was found. Seven trace elements (Ag, Co, Cs, Ga, In, Te, and Tl) were retained or lost to the same extent regardless of the heating conditions. Variations in the apparent activation energy for C above and below 700 C suggest that diffusive loss from different hosts and/or different mobile transport processes over the temperature range may have been in effect.

Ikramuddin, M.↗
NASA NTRS1979

Thermal metamorphism of primitive meteorites. VIII - Noble gases, carbon and sulfur in Allende /C3/ meteorite heated at 400-1000 C

Noble gases, C and S, are lost from Allende samples heated for 1 week at temperatures of 400-1000 C in a low pressure environment. In the extreme, losses of He-3 and He-4 are about 100 x while for C, S and Ne, Ar and Kr isotopes and Xe-132 these are less than or equal to 10 x. Except for He, these losses are less severe than those of Bi or Tl from samples heated in the same runs. Significant He, Ne and Ar isotopic fractionation during heating indicates preferential outgassing of specific reservoirs. Next to He, Ar-40 is the most labile of those species considered here but still less so than Bi or Tl. L-group (but not H- or LL-group) chondrites may have lost mobile elements like Tl while being outgassed after late impact-associated heating. A less likely alternative involving a collateral relation between condensation conditions and depth in a parent object may also explain the L-group trend.

Herzog, G. F.↗
NASA NTRS1979

On volatile element trends in gas-rich meteorites

Ten volatile elements (and non-volatile Co) in co-existing light and dark portions of 5 gas-rich chondrites were studied. Patterns of distinct but non-uniform enrichment by dark admixing material are revealed. The dark admixing material is enriched in Cs; Bi and Tl covary in it. It is compositionally unique from known types of primitive materials and is apparently not derived by secondary processes from such materials.

Bart, G.↗
NASA NTRS1978

Thermal metamorphism of primitive meteorites. VII - Mineralogy-petrology of heated Murchison /C2/ and alteration of C30 and other chondrites

Alterations caused by week-long heating of Murchison in a low-pressure environment at 400-1400 C are of two types: thermodynamically favored kinetically controlled or thermodynamically controlled rapid processes. Kinetically controlled changes pertinent to chondritic evolution and which vary progressively with temperature in heated Murchison include: chondrule blurring; matrix coarsening; increasing mean Fa and Fs contents of ferromagnesian silicates; equilibration of olivine; increasing Mg/Si, Ca/Si, Al/Si, and Cr/Si and decreasing Fe/Si, Ni/Si, and S/Si in matrix; Cr loss from kamacite; and homogenization and Ni-zoning in taenite at high temperatures. Low-temperature thermodynamically controlled changes include: transformation of high-Ni troilite to low-Ni and formation of Ni- and Co-rich metal from pentlandite. High-temperature changes include formation of Cr-rich magnetite and formation of a Ni-rich sulfide similar to that found in highly altered chondrites. Trends resulting from processes of both kinds in Murchison are consistent with characteristics of a postulated C30 metamorphic suite, while those changes caused by reactions of the second kind are similar to those in heavily shock-heated ordinary chondrites and the heavily metamorphosed C5-6 chondrite, Mulga West. Either the simulations support the metamorphic origin of the C30 suite and other thermally induced changes or the natural alterations support the utility of laboratory simulations in studying meteoritic evolution.

Matza, S. D.↗
NASA NTRS1978

Metamorphic effects in experimentally heated Krymka /L3/ chondrite

Experimental charges of the Krymka unequilibrated ordinary chondrite heated from 500-1000 C have been examined petrographically for evidence of metamorphism. Of the petrologic criteria commonly used to distinguish types 4-6 chondrites, only changes in opaque mineral compositions are observed. Chemical and textural observations indicate development of a fine-grained intergrowth of taenite + troilite beginning at 700 C due to melting within the metal-rich portion of the Fe-Ni-S system, and minor reduction of troilite to metal, possibly through sulfur loss at higher temperatures. Overall textural integration, glass devitrification, and significant Fe-enrichment of ferromagnesian minerals are not observed because the short duration of these experiments was not sufficient for the development of other changes normally attributed to metamorphism in ordinary chondritic meteorites.

Mcsween, H. Y., Jr.↗
NASA NTRS1977

Volatile/mobile trace elements in Karoonda /C4/ chondrite

Concentrations of ten volatile/mobile trace elements and of nonvolatile Co in the Karoonda (C4) meteorite were determined, and the atomic abundances relative to C1 are compared with values for the Murchison (C2) and Allende (C3) meteorites. Empirical Bi, In, and Tl data for Karoonda and heated Allende and Murchison are compared with theoretical curves for condensation from a gas of cosmic composition at low pressures. It is suggested that Karoonda might derive from low-temperature open-system metamorphism of pristine C3-like material.

Matza, S. D.↗
NASA NTRS1977

Extraction of trace elements from ores

Trace elements, such as interstitial impurities, can be extracted by low-pressure, relatively low-temperature vaporization from compositions in which they occur.

Ikramuddin, M.↗
NASA NTRS1976

Noble gases and shock effects in the Odessa octahedrite

Noble gas contents and shock effects have been studied in 21 Odessa irons from known geographic locations. Cosmogenic He-3, Ne-21, Ar-38 contents and He-3/Ne-21 ratios vary by factors of 62, 91, 68, and 1.55, respectively, while Ne-22/Ne-21 ratios are virtually constant at 1.07. The samples fall into two groups differing by a factor of 4.1 in exposure age, 1000 in source mass, or some combination of these. Three samples show significant shock effects, two of them to above 130 kbar, probably arising during terrestrial impact from the crater-forming explosion. As in Canyon Diablo plains specimens, noble gas contents do not correlate with siting or shock.

Herzog, G. F.↗