Metamorphism of brecciated ANT rocks - Anorthositic troctolite 72559 and norite 78527Rake samples 72559 and 78527 are annealed rocks of ANT-suite mineralogy and bulk composition. The rocks were presumably derived from ancient lunar highland ANT rocks of cumulate origin. Sample 72559 is polymict and its precursors were anorthositic-troctolitic in composition. Sample 78527 is monomict and of noritic derivation. The precursors were brecciated due to impact processes; 72559 shows evidence of some impact melting. The samples were thermally metamorphosed forming rocks with granoblastic matrix textures. Coexisting matrix pyroxenes indicate equilibration temperatures of 950-1000 C for both rocks. Accessory opaque oxide minerals in the rocks show rather wide compositional variations. These probably primarily reflect compositional ranges inherited from the precursor/s with little integranular equilibration among them during metamorphism.
Document ID
19790055130
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Nehru, C. E. (Brooklyn College Brooklyn, N.Y., United States)
Warner, R. D. (New Mexico Univ. Albuquerque, NM, United States)
Keil, K. (New Mexico Univ. Albuquerque, NM, United States)
Taylor, G. J. (New Mexico, University Albuquerque, N. Mex., United States)