Chromian Pleonaste and Aluminous Picotite in Two Apollo 14 Microbreccias 14306 and 14055

Abstract

SAMPLE 14306 is a rock sample which the astronauts carefully located, photographed and oriented at station G, 70 m west of North Triplet Crater. The lunar surface there is composed of smooth terrain material (Fra Mauro Formation), very gently undulating with subdued craters ranging from a few cm to 2 m in diameter¹. In a hand specimen several shock features were recognizable 40% of the fragments exceeded 1 mm and 60% were smaller matrix fragments. Twenty per cent of the clasts were identified as feldspar, the remaining 80% being lithic fragments of which only 10% were melanocratic. The weight of the sample was 582.8 g and the dimensions 15×6 cm. Sample 14055 was collected from ridge material at station E, also in the Fra Mauro Formation. Station E is located approximately halfway between the lunar module landing site and Cone Crater. The sample is described¹ as a medium grey fine-grained microbreccia with an average grain size less than 1 mm. Only 5% of the clasts exceed 1 mm and they are all lithic and leucocratic. No dark lithic clasts were observed. The sample weight amounted to 110.98 g and the dimensions were 2×5×4.5 cm.