Browse Items (21 total)

  • Collection: (KBR) Karroo Igneous Complex -- Birds River, South Africa

KBR.pdf
OCR PDF of supplemental information for Karroo- Bird's River Petrographic Suite

KBR- 19.JPG
This is a volcanic breccia from the farm Murrelfontein adjacent to the contact with the gabbro unit. It includes partially melted glass and tridymite, a high temperature polymorph of quartz, and has a brecciated appearance. The breccia has a …

607_Dolerite_1
This is dolerite from the "Dragon's Back" dyke, from the farm Romance. It is the youngest dolerite body in the area and contains biotite and hornblende. Emplacement of this dolerite took place at a much deeper crustal level than the gabbros. It has…

KBR- 17.JPG
The metasomatised pyroclastics are from the farm Thysfontein. They are baked and well indurated. Induration is the hardening of rocks by heat or baking as well as the hardening of sediments by cementation or compaction. The pyroclastics are…

KBR- 16.JPG
Adinole was collected from the farm Murrelfontein and occurs above a conspicuous dolerite pegmatite. Adinole is a dense rock of mostly quartz and albite formed as the alteration product of contact metamorphism. It is potassium-rich and has…

KBR- 15.JPG
This hornfels was collected from a section of contact metamorphism immediately above the dolerite of the formation from the farm Murrelfontein. It has "spots" of quartz, most likely inverted from tridymite spherulites, in a matrix of devitrified…

KBR- 14.JPG
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…

KBR- 13.JPG
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…

KBR- 12.JPG
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…

KBR- 11.JPG
The intersertal ferrotholeiite samples are highly fractionated and were most likely emplaced before the gabbro of the formation. They have textures associated with rapidly frozen or highly viscous melts. KBR-7 through KBR-10 are also intersertal…

KBR- 10.JPG
The intersertal ferrotholeiite samples are highly fractionated and were most likely emplaced before the gabbro of the formation. They have textures associated with rapidly frozen or highly viscous melts. KBR-7 through KBR-9 and KBR 11 are also…

KBR- 9.JPG
The intersertal ferrotholeiite samples are highly fractionated and were most likely emplaced before the gabbro of the formation. They have textures associated with rapidly frozen or highly viscous melts. KBR-7, KBR 8, KBR 10, and KBR 11 are also…

KBR- 8.JPG
The intersertal ferrotholeiite samples are highly fractionated and were most likely emplaced before the gabbro of the formation. They have textures associated with rapidly frozen or highly viscous melts. KBR-7 and KBR-9 through KBR-11 are also…

KBR- 7.JPG
The intersertal ferrotholeiite samples are highly fractionated and were most likely emplaced before the gabbro of the formation. They have textures associated with rapidly frozen or highly viscous melts. KBR-8 through KBR-11 are also intersertal…

KBR- 6.JPG
KBR-3 through KBR-6 are a second gabbro mass, distinguished from the first by a repetition of the differentiation cycle. Between the location this sample was collected and the location KBR-7 was collected there is a thin gabbro pegmatite that was…

KBR- 5.JPG
KBR-3 through KBR-6 are a second gabbro mass, distinguished from the first by a repetition of the differentiation cycle. The gabbro is medium grained and holocrystalline with a hypidiomorphic-granular texture. There are gray and black crystals, both…

KBR- 4.JPG
KBR-3 through KBR-6 are a second gabbro mass, distinguished from the first by a repetition of the differentiation cycle. The gabbro is medium grained and holocrystalline with a hypidiomorphic-granular texture. There are gray and black crystals,…

KBR- 3.JPG
KBR-3 through KBR-6 are a second gabbro mass, distinguished from the first by a repetition of the differentiation cycle. The gabbro is medium grained and holocrystalline with a hypidiomorphic-granular texture. There are gray and black crystals, both…

KBR- 2A.JPG
Samples KBR-1, KBR-2, KBR-2A are from a vertical mass of gabbro showing progressive differentiation inward.This sample is the second sample for KBR-2. This sample is medium grained and holocrystalline with a hypidiomorphic-granular texture. There are…

KBR- 2.JPG
Samples KBR-1, KBR-2, and KBR-2A are from a vertical mass of gabbro showing progressive differentiation inward. This sample is medium grained and holocrystalline with a hypidiomorphic-granular texture. There are gray and black crystals, both ranging…