Figure F37. Photomicrographs showing the morphology and composition of the discrete, round Cr spinel phenocrysts of Unit 17 (Sample 197-1206A-38R-1 [Piece 2B, 55-58 cm]) (reflected light; field of view = 0.625 mm). A. Extensive development of titanomagnetite on a relict Cr spinel (photomicrograph 1206A-362). B. Another example of extensive development of titanomagnetite on a relict Cr spinel (photomicrograph 1206A-362). C, D. Two generations of titanomagnetite. The larger masses have resulted from the complete replacement of discrete Cr spinel phenocrysts by titanomagnetite, which has subsequently developed ilmenite oxidation lamellae. The smaller crystals are typical groundmass titanomagnetite: (C)photomicrographs 1206A-363; (D) photomicrograph 1206A-361.

Figure F37. Photomicrographs showing the morphology and composition of the discrete, round Cr spinel phenocrysts of Unit 17 (Sample 197-1206A-38R-1 [Piece 2B, 55-58 cm]) (reflected light; field of view = 0.625 mm). A. Extensive development of titanomagnetite on a relict Cr spinel (photomicrograph 1206A-362). B. Another example of extensive development of titanomagnetite on a relict Cr spinel (photomicrograph 1206A-362). C, D. Two generations of titanomagnetite. The larger masses have resulted from the complete replacement of discrete Cr spinel phenocrysts by titanomagnetite, which has subsequently developed ilmenite oxidation lamellae. The smaller crystals are typical groundmass titanomagnetite: (C)photomicrographs 1206A-363; (D) photomicrograph 1206A-361.