2 20 21 https://geosciencecollections.milne-library.org/files/original/594db1386a179c05d29cc9bb64187733.JPG c65e05a2530c0798bd961be76bbf646d Omeka Image File The metadata element set that was included in the `files_images` table in previous versions of Omeka. These elements are common to all image files. Width 1936 Height 2592 Bit Depth 8 Channels 3 https://geosciencecollections.milne-library.org/files/original/372c2e3e7e4eb57fddb14de28d5102ff.JPG 88bbe3c580b3d10238c8d753fc4f2fab Omeka Image File The metadata element set that was included in the `files_images` table in previous versions of Omeka. These elements are common to all image files. Width 2560 Height 1920 Bit Depth 8 Channels 3 https://geosciencecollections.milne-library.org/files/original/616e043bae92f9331a74e755fb0e09d8.JPG 096eeceb5ca59e46960e6322a9f4d93d Omeka Image File The metadata element set that was included in the `files_images` table in previous versions of Omeka. These elements are common to all image files. Width 2560 Height 1920 Bit Depth 8 Channels 3 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource (KBR) Karroo Igneous Complex -- Birds River, South Africa Description An account of the resource The Birds River Complex is a "Bell-Jar" intrusion first described by du Toit in 1905 and then by Ealey and Robey in 1976. One of the best exposed sections across the margin of the complex is on the farm Denwood, in the southwestern corner of the complex. The samples were collected from a mafic intrusion near Denwood farm. These samples from the Karroo Complex were collected from the previously studied section of the complex and neighboring areas. Contributor An entity responsible for making contributions to the resource Dr. Brian Lock, Rhodes University Western Minerals, Inc. References A related resource that is referenced, cited, or otherwise pointed to by the described resource. Start Here: Cox, K.G., 1972, The Karroo Volcanic Cycle: Journal of the Geological Society, v. 128, p. 311-336.Â doi: 10.1144/gsjgs. 128.4.0311. <ul><li>The petrogenesis of the Mesozoic igneous rocks of south-Eastern Africa is related to the tectonic event believed to be the initiation of the break up of Gondwanaland. The cycle began with the rise of potassium-rich picritic magma, the source material for rocks of the northern province, Rhodesia. On top of and peripheral to the main magma body, a zone of sodic magma was generated and formed some of the rocks of the north and most southern rocks.</li> </ul> Additional resources: White, R.S., 1992, Magmatism During and After Continental Break-Up, Geological Society, London, Special Publications, v. 68, p. 1-16. doi:Â 10.1144/GSL.SP.1992.068.01.0. <ul><li>Magmatism that goes along with continental break-up is caused primarily by decompression melting of the underlying mantle as it rises up beneath the rift. The amount of melt produced is determined by the asthenospheric mantle temperature and on the rate of rifting.Â </li> </ul>Eales, H.V., and van Robey, J.A., 1976, Differentiation of Tholeiitic Karroo Magma at Birds River, South Africa, Contributions to Mineralogy and Petrology 10. v. 56, p. 101-117. doi:Â 10.1007/BF00375423 <ul><li>Strongly fractionated residue from the partial crystallization of tholeiitic gabbroic magma was emplaced at depth within sediment of the upper part of the Karroo succession. The residue was most likely tapped from a deeper intrusion during cauldron subsidence, but was engulfed by a later intrusion of olivine gabbro on a large scale.</li> </ul> Walker, F., and Poldervaart, A., 1949, Karroo Dolerites of the Union of South Africa, Geological Society of America Bulletin, v. 60, p. 591-706. doi: 10.1130/0016-7606(1949)60[591:KDOTUO]2.0.CO;2 <ul><li>The Karroo dolerites are the result of the intrusive phase of the early Jurassic basalts that built up the Basutoland lava plateau. Most of the dolerites show little differentiation but olivine rich types and acidic veins have been recorded. The magma had an effect on the sedimentary rocks; many of the rocks described as granophyre were found to be transformed siltstone. The dolerites occur as sills and dikes but "bell-jar inclusions" occur (the Bird's River complex is a bell jar shaped inclusion).Â </li> </ul> Eales, H.V., and Booth P.W.K., 1974, The Birds River Gabbro Complex, Dordrecht District, Transactions of the Geological Society of South Africa, v. 77, p. 1-15. <ul><li>On the gabbros of the Birds River Complex.</li> </ul> Rock A physical material with a mineral composition. Unit Formation or other descriptive rock category Lesotho Formation Number of Thin Sections Number of thin sections associated with this sample 1 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Tholeiitic Gabbro Alternative Title An alternative name for the resource. The distinction between titles and alternative titles is application-specific. Gabbro Description An account of the resource 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 from <1mm- 3mm. There is a red rusty looking weathered surface. This rock has an average specific gravity. Thin section images are shown in plain and cross polarized light at40x magnification. The gabbro is composed of 65% plagioclase, 30% pyroxene, 3% oIivine, and 2% opaques. Date A point or period of time associated with an event in the lifecycle of the resource No date given. Contributor An entity responsible for making contributions to the resource Western Minerals, Inc Is Part Of A related resource in which the described resource is physically or logically included. http://www.geosciencecollections.milne-library.org/collections/show/17 Identifier An unambiguous reference to the resource within a given context KBR-1 Spatial Coverage Spatial characteristics of the resource. Karoo- Birds River, Eastern Cape, South Africa Temporal Coverage Temporal characteristics of the resource. 183-179 Ma (Jurassic) Accrual Method The method by which items are added to a collection. Purchased from Western Minerals Inc