 | | Journal (article/letter/editorial) |
| magmas: implications from natural carbonatites, Namibia B. Bühn Instituto de Geoci^encias, University... Summary Two bimodal carbonatite complexes in Namibia of Cretaceous age are explored as to the presence...composition of a coexisting carbonatitic fluid. The Kalkfeld and Ondurakorume complexes contain both Ca- and...geochemical evolution of low-Si carbonatite bodies in Namibia, and addresses the response of carbonatite compositions...bodies considered are the Kalkfeld and Ondurakorume carbonatites in northern Namibia, which are part of the |
 | | Report (issue) |
| SURVEY NAMIBIA 1990 Open File Report MRS 12 2 Abstract Niobium-tantalum mineralisation in Namibia occurs...basement rocks of the Namaqualand Metamorphic Complex, and with rare metal pegmatites of late Namibian...by-products of Tin-mining operations in central Namibia (Uis, Nainais, De Rust). Prominent niobium-tantalum...pegmatites occur in the Tantalite Valley in southern Namibia and have been mined for a long time on a small...basement rocks of the N'amaqualand Metamorphic Complex 2.1.1 Tantalite Valley pegmatites 2.1.1.1 Witkop |
 | | Journal (article/letter/editorial) |
| quartzitic country rocks of the Kalkfeld carbonatite complex, Namibia. The fluid inclusion population...relationship to the volatile-deficient, parental Kalkfeld carbonatite. Individual fluid inclusions display...this respect are similar to those of the parental Kalkfeld carbonatite, but are distinguished by a negative...carbonatitic fluid with the volatile-deficient, sövitic Kalkfeld carbonatite suggests that virtually all alkali...Rankin Fig. 1. Geological map of the Kalkfeld igneous complex (modified after Van Zijl, 1962), with |
 | | Journal (article/letter/editorial) |
| African carbonatite complexes. Except for one complex analyzed for comparison (Okorusu), all other complexes...HC34 and a concomitant decrease in CaO. The Kalkfeld complex is Cretaceous in age, and belongs to a group...with the Damaraland magmatic province in northern Namibia (e.g., le Roex and Lanyon 1998). The samples were...The Ondurakorume complex is located close to the Kalkfeld complex in northern Namibia. Again, a suite...rocks is exposed (Prins 1981). In contrast to Kalkfeld, magnesiocarbonatite varieties with up to 13 wt% |
 | | Book |
| REPUBLIC OF NAMIBIA - MINISTRY OF MINES AND ENERGY GEOLOGICAL SURVEY THE MINERAL RESOURCES OF NAMIBIA FIRST...ENERGY Of the several hundred minerals present in Namibia, around sixty have been exploited. some, such as...base metals and industrial minerals have helped Namibia rank amongst the top five mining countries in Africa...terms of production and reserves. In this context, Namibia is a major producer of copper, lead, zinc, cadmium...unpublished. It is evident that mineral exploration in Namibia, as elsewhere. has changed from serendipitous discoveries |
 | | Book (edition) |
| detailed geological survey of the Alné Island complex and announced his results in a series of papers...completed most of the field work on the Iron Hill complex of Gunnison County, Colorado, in 1912-1913. Although...fairly pure calcite (Garson and Smith, 1958). The complex was first studied by F. Dixey, and it was he who...detailed and complete studies of a carbonatitic complex. Between 1950 and 1956 there took place the most...presented by Leonardos (1956A, B). The Fen, Norway, complex has been restudied by Saether (1958); that of the |
 | | Report (issue) |
| third order administrative area, basin/formation/region(area)/deposit, and deposit/site name. Guano and...third order administrative area, basin/formation/region(area)/ deposit, deposit/site name, deposit type...information in the next two fields, .Basin/Fmt/Region (area)/Deposit and Deposit/Site_Name, is meant...Age, Host/Associated Lithology, Host Formation/Complex, Minerals, and Geologic Comments/Deposit Description...Yacimientos no metaliferos y rocas de aplicacion de la region Patagonia-Comahue: Argentina Ministerio de Economia |
 | | Book |
| magmatism of the eastern margin of the Atlantic (Namibia, Angola) or the western African kimberlites do...Mafic-Ultramafic Magmatism in the Southwest Uganda Region of the African Rift: Implications from Experimental.... . . ... 3 The Crust Under the Canary Islands Region ............. 4 Network of Fractures and Identity...Identity of Vertical Movements in the Canary Islands Region ........................... 4.1 Transoceanic and......................... 5.1 The Thghouaji Ring-Complex ...................... 5.2 Conclusion ........ |
 | | Book |
| simplest way to visualize the chemical composition of complex silicate materials is as a mixture of oxides: silicon...NaAlSi3O8). Solid solution in pyroxenes is more complex, so representing the composition of a pyroxene...be ignored. Garnet compositions are still more complex and require six end-members (Box 5.2). Such ‘formula... see Fig. 1.5); the dashed lines delineate the region of overlap between alkali and subalkali basalts... The circumstances behind this transition are complex. The field evidence may be summarized as follows: |
