Engineering Papers⌕ Search

Engineering topics

Delano, J. W.

Publications and source records attributed to Delano, J. W..

33 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Abundancies of Ni, Cr, CO and major elements in the silicate portion of the Moon: Constraints from primary lunar magmas

The lunar volcanic glasses are samples of primary magnas derived by partial melting of the Moon mantle. The twenty-seven varieties of glass define three linear arrays having nearly constant Mg/Si ratios. The low-Ti magmas in each array approach the chondritic Ti/Al ratio. In addition, the Ca/Al ration in these low-Ti magmas trends toward the chrondritid value as one proceeds from array 1 through array 3. Using the chemistries of these primary magmas, as well as the assumption that the Moon possesses chondritic Ca/Al/Ti/Mg ratios, the silicate composition of the Moon has been estimated. The implications of these results are discussed.

Delano, J. W.↗
NASA NTRS1983

Mare glasses from Apollo 17 - Constraints on the moon's bulk composition

Two previously unreported varieties of mare volcanic glass have been discovered in Apollo 17 samples. Twenty-three chemical types of volcanic glass have now been analyzed from the six Apollo landing sites. These volcanic glasses, which may be samples of primary magmas derived from the differentiated lunar mantle, define two linear arrays that seem to reflect regional, if not global, regularities among the source regions of these melts. Additional systematics among these glasses have been used to estimate the bulk composition of the moon. The results suggest that the refractory lithophile elements are present at abundances of 1.7 x chondrites. The silicate portion of the moon appears to have a major-element composition similar to a volatile (Si, Na, K)-depleted, earth's upper mantle. The theory involving an earth-fission origin of the moon can be tested further through trace element analyses on the volcanic glasses, and through determination of the N/Ar-36 ratio and noble gas isotopes from primordial lunar gas trapped within vesicles associated with mare volcanic glass.

Delano, J. W.↗
NASA NTRS1982

Chemical systematics among the moldavite tektites

The compositional variations that occur among the moldavite tektites are caused principally by incomplete mixing of two components during fusion. With the possible exception of silica, there is no evidence for significant losses of volatile species by fractional vaporization. Chemical constraints have been calculated for the two source-materials that contributed to the moldavites. If these tektites were formed by impact fusion, as is commonly believed, then the compositional systematics preserved within the moldavites suggest that hypersonic flow and ejection of impact melts are orderly processes. Insights gained from the study of tektites should prove useful in interpreting the chemistries of impact glasses from other bodies in the solar system.

Delano, J. W.↗
NASA NTRS1982

Glasses of impact origin from Apollo 11, 12, 15, and 16 - Evidence for fractional vaporization and mare/highland mixing

Electron microprobe analyses have been performed on glasses of impact origin in Apollo 11 breccias (10059, 10060, 10061), Apollo 12 soil (12070), and Apollo 15 breccias (15318, 15425, 15426, 15427). These glasses were produced by shock melting of regolith, rather than of rock. Simple concepts for better understanding and interpreting the chemical data from impact glasses have been developed. These concepts are a significant improvement on earlier strategies, which centered principally on cluster analysis. Using ratios of refractory lithophile elements, the compositional effects of fractional vaporization often associated with impact melting to obtain chemical information about the mare and highland components in the regoliths parental to the glasses have been 'seen through'. This method is also applied to the mare-derived impact glasses from Apollo 16 in order to place constraints on the types of volcanic components occurring in Mare Nectaris. Since impact glasses can be used to derive chemical constraints on the indigenous lithologies comprising multi-component regoliths; the frequent occurrence of these glasses, as well as their low masses, should make them critically important for study when small quantities of grab-samples are returned by future unmanned spacecraft from planets, satellites, and asteroids where regoliths are present.

Delano, J. W.↗
NASA NTRS1982

The Apollo 15 yellow impact glasses - Chemistry, petrology, and exotic origin

The Apollo 15 yellow impact glasses are characterized by moderate TiO2 (about 4.8%) and high abundances of the large ion lithophile elements (e.g., K, P, Hf, Th, REE). Since the chemistry of these glasses cannot be duplicated by any combination of local components presently known to occur at the Apollo 15 landing site, these yellow glasses seem to be exotic to that area. Chemical and petrologic constraints suggest that these samples were produced by impact melting of an immature mare regolith developed upon an unusual variety of mare basalt. It is speculated that the target basalts were the youngest lava flows known to exist on the moon (i.e., Eratosthenian-age lavas in Oceanus Procellarum and Mare Imbrium). Specific tests are proposed for evaluating this provocative hypothesis.

Delano, J. W.↗
NASA NTRS1982

Chemistry and phase relations of VLT volcanic glasses from Apollo 14 and Apollo 17

The VLT (very low titanium) volcanic glasses from Apollo 14 and Apollo 17 have been analyzed for the major elements and trace Ni. These glasses display compositional trends that may not result entirely from olivine fractionation. The phase relations have been determined experimentally. Olivine is the liquidus phase in the pressure interval from 0 to about 18 kbar. Pigeonite is the liquidus phase from about 18 kbar to 22 kbar or more. If these VLT volcanic glasses are samples of primary melts that had been in chemical equilibrium with olivine and low-Ca pyroxene in their source regions, then these liquids were derived from depths of 360-380 km within the moon.

Chen, H.-K.↗
NASA NTRS1981

Lunar volcanic glasses and their constraints on mare petrogenesis

The compositional properties of volcanic glasses from the Apollo 11, 14, 15 and 16 landing sites are examined and implications of the results for mare basalt petrogenesis and deep lunar structures are discussed. Major-element and nickel analyses were performed on the glasses using electron probe techniques, and R-mode principal component analysis was performed on the 19 different compositions of glass distinguished. The glasses are found to form two distinct chemical arrays based on the major elements and Ni. The presence of two chemically isolated cumulate systems in the mantle at different depths is thus inferred, and a model is developed for mare petrogenesis in which each system was itself composed of two lithologic components that underwent hybridization, assimilation or mixing to generate the large compositional range of magmas represented by the lunar volcanic glasses. The surface-correlated elements associated with the volcanic glasses are attributed to another reservoir in the deep interior which may be responsible for gas emissions causing lunar transient phenomena. The model developed allows predictions to be made concerning the liquidus phase relations, trace and radiogenic element distributions, nonradiogenic isotope compositions and sample ages.

Delano, J. W.↗
NASA NTRS1977

4.2-4.3 AE anorthositic soil fragments - Equilibrated or unequilibrated polycomponent systems

The petrographies and phase chemistries of five lunar crystalline anorthositic fragments with Ar-40/Ar-39 plateau 'ages' ranging from 4.1 to 4.3 AE are reported. An investigation is conducted to determine whether the individual fragments are monomict or polymict breccias. For polymict breccias it is attempted to establish whether clasts and matrix have equilibrated chemically. On the basis of the results of the investigation it is suggested that sample 73263,1,1 was a breccia (possibly a clast-laden melt) containing old clasts, incorporated in an ejecta blanket that was annealed at about 4.1 AE in a transient high-temperature event. The sample 73263,1,6 studied is an annealed anorthositic breccia containing approximately 20% clasts dominated by single-crystal plagioclase fragments. The obtained data are consistent with a two-component system containing old plagioclase clasts in a young (about 4.0 AE) annealed, matrix. The annealing event at approximately 4.0 AE was insufficient to equilibrate the argon. It is found that four of the breccias having ages of about 4.2 AE or more are polymict. The most striking feature of all of the samples studied is the presence of a significant amount of 4.2-4.3 AE argon.

Delano, J. W.↗
NASA NTRS1977

Experimental melting relations of 63545, 76015, and 76055

The experiments discussed were conducted for the purpose of placing additional constraints on the origin of lunar highlands noritic compositions. The sample 63545 represents a fine-grained, crystalline melt rock consisting of pink spinel, plagioclase, divine, interstitial glass, minor oxides, and metal. According to Chao (1973), 76055 is an olivine-bearing micronorite hornfels with abundant xenocrysts and xenoliths. The sample 76015 is a vesicular, poikilitic impact melt with a homogeneous matrix. The obtained experimental melting relations of 63545, 76055, and 76015, are examined, taking into account experimental petrology and trace element chemistry of mare basalts. It is concluded that the studied compositions do not represent magmas derived by partial melting of either cosmic or differentiated source regions at any pressure in the moon. Presently available information would seem to favor an origin by impact-fusion of several highlands components.

Delano, J. W.↗
NASA NTRS1974

Petrology of the highlands massifs at Taurus-Littrow - An analysis of the 2-4 mm soil fraction

The petrography, phase chemistry, and Ar-40/Ar-39 ages of 2-4 mm fragments from the soils of both mare and highlands stations sampled by Apollo 17 are studied. It is found that the massifs consist of a complex stratigraphy of interlayered noritic breccias of varying metamorphic grades, melt rocks, and anorthositic rocks. A stratigraphic correlation of the lithologies within the North Massif and the South Massif is carried out. The petrogenesis of rock types with respect to thermal and impact history is discussed. The observed spinel cataclasites may represent relatively deep material sampled by the Serenitatis event.

Bence, A. E.↗
NASA NTRS1973

Pyroxene poikiloblastic rocks from the lunar highlands

The results of detailed petrographic, X-ray, electron microprobe, ion probe, and Ar-40/Ar-39 age studies of pyroxene poikiloblastic breccias, an important lunar highlands lithology, are interpreted to indicate that high grade metamorphic recrystallization occurred over wide regions of the moon at about 4.0 G.y. This metamorphism was probably related to a period of high meteorite influx at that time. The temperatures achieved were highly variable but in some cases were sufficiently intense to cause varying degrees of partial melting of the precursor highlands breccias. A complete spectrum of metamorphic grades from only slight recrystallization to virtually complete melting would be expected in such a model. Such a spectrum is observed in the Apollo 16 rocks.

Bence, A. E.↗