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Nelen, J.

Publications and source records attributed to Nelen, J..

9 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Meteoritic, lunar and Lonar impact chondrules.

Impact-generated silicate spherules from the Lonar Crater, India and from all Apollo sites are analogous to meteoritic chondrules (and some microtektites). Thus, the impact origin of chondrules, first proposed by Urey (1952) is a mechanism strongly supported by physical evidence from both the moon and the earth. Chondrites appear to be essentially impact breccias similar to lunar and Lonar microbreccias. The implications of this with regard to size and composition of the meteorite parent bodies are reviewed as well as the possible variations of element fractionation by volatilization-condensation.

Fredriksson, K.↗
NASA NTRS1971

A summary of phase analysis on Apollo 14 samples

The results of an analysis of lunar samples from Apollo 14 are presented. The large number of breccias returned from the Fra Mauro formation show that impact events are an important rock forming mechanism on the moon. Larger rocks as well as micro breccias bear structural resemblance to brecciated chondrites and terrestrial impactites. Many show evidence of repetitious events of break-up and accumulation welding. The surface of the regolith has become thoroughly mixed by this process. Most components however appear locally derived from basalts rich in feldspar and Kreep components, similar to rocks such as 14310.

Fredriksson, K.↗
NASA NTRS1971

Transition element distribution in stony meteorites and in terrestrial and lunar rocks.

Discussion of the distribution of the transition elements (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) among the individual minerals of stony meteorites, and comparison with data on comparable lunar and terrestrial minerals. As an example of meteorite distribution patterns, data on the Modoc meteorite are presented. For the lunar rocks, microprobe data are used, along with published information from other investigators. For comparison with terrestrial igneous rocks, Skaergaard intrusion rocks are used. They present some striking analogies in mineralogy and petrology with the lunar igneous rocks and are thus peculiarly suitable for this cross comparison.

Mason, B.↗