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Mueller, H. W.

Publications and source records attributed to Mueller, H. W..

4 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Laser /39/Ar-/40/Ar dating of two clasts from consortium breccia 73215

A laser Ar-39-Ar-40 study of the components of an ANT-suite anorthositic gabbro and a black aphanite from a consortium breccia is reported. A wide range of K-Ar ages is found for the plagioclase in the anorthositic gabbro; at the centers of the largest grains is material showing the greatest age (older than 4.11 billion years) while the youngest material (3.81-3.88 billion years) is found near the grain margins. Partial outgassing of the clasts upon incorporation into the breccia could account for the age patterns. The black aphanite clast appears to be cogenetic with the aphanite that forms the breccia matrix. The time of crystallization of a lunar granite has also been measured by the laser technique.

Eichhorn, G.↗
NASA NTRS1977

Laser Ar-39-Ar-40 study of Apollo 17 basalts

Three Apollo 17 basalts were studied by the laser Ar-39-Ar-40 method. The 70215 basalt has a normal well-behaved Ar-39-Ar-40 release pattern; the 70017 basalt has a disturbed release pattern which indicates a limited intermediate maximum age followed by a broad low-age region; and the 75035 basalt has a pattern initially similar to 70017 that is followed by a high-temperature maximum age. The laser study shows that all mineral systems in 70215 have small and uniform temperature losses, while the laser-determined ages for 70017 and 75035 are, apparently, primarily controlled by the minerals containing mesostasis inclusions. It is possible that the drop in ages observed by the conventional Ar-39-Ar-40 method was due not only to recoil of Ar-39 during neutron irradiation but also to gas loss from some minerals. It is suggested that the plagioclases are the best minerals to use for a reliable age.

Schaeffer, O. A.↗
NASA NTRS1977

Laser probe /Ar-39/-/Ar-40/ dating of materials from consortium breccia 73215

The unique capacity of the laser-probe (Ar-39)-(Ar-40) method to determine ages of constituents in a rock sample which are only of the order of 100 microns apart has been applied to measure ages of the different constituents of consortium breccia 73215. Evidence is given that the age of the melt-derived ground mass, 4.01 + or - 0.05 billion years, has no chronological significance. Instead, the best estimate for the age of the breccia-forming event, about 3.90 billion years, comes from the study of two clasts only a few hundred micrometers in size. The interpretation of this age as the age of the breccia-forming event is also supported by the studies of other consortium members and suggests a reinterpretation of the ages of most of the other Apollo 17 highland breccias.

Mueller, H. W.↗