Porphyroblastic Metasediments
The porphyroblastic metasediments/hybrid rocks were interpreted by Eales and his co-workers to be metamorphosed "Red Beds" Formation sediments but could be magmatic in origin. The samples illustrate the range in textures; see KBR 12 and KBR 13 to note this range. This sample is medium grained, holocrystalline, and has a hypidiomorphic-granular texture. It has dark gray crystals, ranging from < 1 mm- 3 mm. Dramatic labradorite-like striations cover about half of the rock. Groups of striations are roughly at right angles to one another. The rusty looking weathered surface is more vibrant on this rock (than the other samples).
The thin sections shown in plain polarized Light and cross polarized light at 40x magnification.
The rock is 60% plagioclase, 40% pyroxenes (mainly enstatite), and <1% opaques.
No date given.
Western Minerals, Inc.
KBR-14
Porphyroblastic Metasediments
The porphyroblastic metasediments/hybrid rocks were interpreted by Eales and his co-workers to be metamorphosed "Red Beds" Formation sediments but could be magmatic in origin. The samples illustrate the range in textures; see KBR 12 and KBR 14 to note this range. This sample has an aphanitic- porphyritic texture and is holocrystalline. There is a light gray anhedral ground mass and medium-grained phenocrysts (1 mm- 3 mm).There are fine, snaky veins of reddish material on the fresh surface. Minor euhedral phenocrysts of plagioclase with reaction rims (4 mm).
The thin sections shown in plain polarized light and cross polarized light at 40x magnification.
The rock is 40% plagioclase, 20% pyroxenes (Enstatite), and 20% opaques.
No date given.
Western Minerals, Inc.
KBR-13
Porphyroblastic Metasediments
The porphyroblastic metasediments/hybrid rocks were interpreted by Eales and his co-workers to be metamorphosed "Red Beds" Formation sediments but could be magmatic in origin. The samples illustrate the range in textures; see KBR 13 and KBR 14 to note this range. This sample has an aphanitic porphyritic texture. There are unfoliated coarse-grained metasediments (2 mm- 4 mm) and subhedral muscovite phenocrysts (2 mm - 3 mm) as well as red anhedral phenocrysts. There is a rusty-looking weathered surface. In thin section, radiating pyroxenes are clearly visible.
Thin sections are shown in plain polarized light and cross polarized light at 40x magnification.
The rock is comprised of 70% plagioclase, 22% pyroxene (mainly augite), and 8% opaques.
No date given.
Western Minerals, Inc.
KBR-12