Engineering topics

Lange, D. E.

Publications and source records attributed to Lange, D. E..

6 records

NASA NTRS1979

The Shaw meteorite - History of a chondrite consisting of impact-melted and metamorphic lithologies

Three intermingled lithologies are identified in the Shaw L-group chondrite: a light-colored lithology with a poikilitic texture, consisting of olivine and augite crystals surrounded by larger orthopyroxene grains; a dark-colored lithology containing remnant chondrules and exhibiting a microgranular texture; and a gray lithology which appears to be intermediate between the other two. Contrary to published opinions, the Shaw meteorite contains normal L-group chondrite abundances of metal and troilite, though these phases are irregularly distributed. The lithological analyses suggest that 4.52 Byr ago an impact took place on the L-group chondrite parent object of Shaw.

Taylor, G. J.↗

NASA NTRS1978

The Galatia, Kansas, chondrite

The paper describes the Galatia meteorite found August 1971 approximately 7 km ENE of Galatia, Barton County, Kansas (98 deg 53 min W, 38 deg 39.5 min N). The single stone weighed 23.9 kg and is partially weathered. Olivine (Fa 24.9) and pyroxene (Fs 20.9) compositions indicate L-group classification, and textural observations indicate that the stone is of petrologic type 6. While Galatia is similar in many respects to the Otis L6 chondrite found 20 miles to the west, Galatia does not have the brecciated structure of Otis and is therefore not part of the same fall.

Van Schmus, W. R.↗

NASA NTRS1978

Chemistry and petrology of Luna 24 lithic fragments and less than 250-micron soils - Constraints on the origin of VLT mare basalts

Results are reported on a combined INAA-petrologic study of 17 small (0.2-1.5 mg) Luna 24 lithic and mineral fragments and INAA study of 5 bulk soils and mineral separates from gabbro 24170. Lithic and mineral fragments are classified into VLT mare basalts (ferrobasalt and metabasalts), low-Ti, variolitic mare basalt, gabbros, melt rock and soil breccia. Data indicate 5 possible magma types, represented by: (1) VLT ferrobasalt and gabbro fragments, with low-TiO2 (about 1%), slightly bow-shaped REE pattern, and low REE concentrations (5-10X chondritic); (2) a ferrobasalt (Laul et al., 1978) and metabasalt fragments with major and trace element contents similar to (1), but positive Eu anomalies; (3) one gabbro fragment with distinctive pyroxene compositional trend (increasing Ti with nearly constant Fe/Fe + Mg) and highest REE contents of any Luna 24 mare basaltic sample, (4) a gabbro fragment with considerably less V and Cr2O3 than ferrobasalt and metabasalt fragments; and (5) variolitic basalt fragment with higher Ti2(2.3%) than other Luna 24 basalts and pyroxene that has increasing then decreasing Ti with increasing Fe/Fe + Mg. Trace element data place constraints on the nature of the source region and possible parent magmas for the Luna 24 VLT ferrobasalt.

Ma, M.-S.↗

NASA NTRS1977

The Kramer Creek, Colorado meteorite - A new L4 chondrite

Results of bulk chemical analyses and mineralogical and petrographic studies of a chondrite found at Kramer Creek, Colorado, are reported. The meteorite has been classified as an L-group chondrite on the basis of its bulk chemistry, the fayalite content of its olivine (21.7%) and the ferrosilicate content of its pyroxene (18.3%). The presence of interstitial glass and the iron oxide percent mean deviations for olivine and low-Ca pyroxene (2.4 and 4.6%) place the specimen in petrologic group 4 of the Van Schmus and Wood classification (1967)

Gibson, E. K., Jr.↗

NASA NTRS1973

Chondrules - An origin by impacts between dust grains

Modern theories regarding the origin of chondrules may be divided into two broad categories. According to primary theories, chondrules are thought to condense directly from the cooling nebular gas as stable or metastable liquid droplets. According to secondary theories, chondrules are thought to be produced by the flash heating and remelting of the original dust-like condensate. A collisional mechanism of chondrule formation is discussed.

Lange, D. E.↗

NASA NTRS1973

The Willowbar meteorite

Results of microscopic and electron microprobe analyses of a meteorite which fell near Willowbar, Okla., in December 1971. Microscopic examination confirmed the differences in structure which could be seen on the cut faces. Three distinct regions could be recognized: unblackened, blackened, and black veins. Microprobe analyses of the silicate grains in the Willowbar meteorite show that it is an L chondrite. The lack of well-defined chondrules and the large size of the maskelynite grains suggests that it is a type 6 chondrite according to the classification of Van Schmus and Wood (1967). It also has large black veins of the same composition as the matrix, and thus it might best be described as a shock-brecciated L6 chondrite.

Lange, D. E.↗