Thesis (M.Sc.) -- University of Adelaide, Dept. of Economic Geology, 1976.

No description available.

Renosterkop is a large low grade tin-tungsten-zinc deposit located 85km WSW of Upington in the northern Cape Province, South Africa. The mineralization is hosted by a number of shallow-dipping, sheeted greisen bodies that are surrounded by, and partly intercalated with a well foliated granite gneiss country rock. The gneiss is taken to belong to the intrusive Riemvasmaak gneiss of the Namaqualand Metamorphic Complex. The mineralized host (referred to as TBQ) is a grey, homogeneous, fine to medium grained rock composed predominantly of quartz, biotite and topaz with minor amounts of fluorite and accessory opaque minerals, zircon and secondary chlorite. The unmineralized granite gneiss country rock is medium-to coarse-grained, pinkish in colour and composed primarily of microcline, plagioclase, quartz and biotite, with or without hornblende. Rock types, transitional in mineralogy but with clearly distinguishable contacts, are present between the TBQ and the granite gneiss. A prominent chemical and mineralogical halo, 20m to 50m wide, envelopes the Renosterkop deposit. There is a gradational transition from an unaltered hornblende biotite gneiss, through gneiss containing greenish-brown biotite to an approximately 2 m wide transition zone, characterized by the partial replacement of the greenish-brown biotite by chlorite. The transition zone in turn yields to the TBQ in which reddish-brown biotite forms at the expense of the chlorite, and topaz, quartz and fluorite are formed at the expense of the feldspar. Major and trace element analyses show a spectrum of chemical compositions with coherent trends that support a gradational transition from the hornblende-bearing granite gneiss, through the transitional rock types to the TBQ. The mineralogical and chemical characteristics of the Renosterkop rock types are consistent with an origin by progressive greisenization of a "within plate" A- type granitoid host rock. A genetic model is proposed which involves the formation of the TBQ greisen during intense metasomatic alteration and replacement of the granite gneiss within a zone of structural weakness that provided conduits for migrating, F-rich, metal-bearing solutions, and thereby inherited the foliation and structural features present in the original granite gneiss. / Thesis (MSc)--PU vir CHO, 1987.

Renosterkop is a large low grade tin-tungsten-zinc deposit located 85km WSW of Upington in the northern Cape Province, South Africa. The mineralization is hosted by a number of shallow-dipping, sheeted greisen bodies that are surrounded by, and partly intercalated with a well foliated granite gneiss country rock. The gneiss is taken to belong to the intrusive Riemvasmaak gneiss of the Namaqualand Metamorphic Complex. The mineralized host (referred to as TBQ) is a grey, homogeneous, fine to medium grained rock composed predominantly of quartz, biotite and topaz with minor amounts of fluorite and accessory opaque minerals, zircon and secondary chlorite. The unmineralized granite gneiss country rock is medium-to coarse-grained, pinkish in colour and composed primarily of microcline, plagioclase, quartz and biotite, with or without hornblende. Rock types, transitional in mineralogy but with clearly distinguishable contacts, are present between the TBQ and the granite gneiss. A prominent chemical and mineralogical halo, 20m to 50m wide, envelopes the Renosterkop deposit. There is a gradational transition from an unaltered hornblende biotite gneiss, through gneiss containing greenish-brown biotite to an approximately 2 m wide transition zone, characterized by the partial replacement of the greenish-brown biotite by chlorite. The transition zone in turn yields to the TBQ in which reddish-brown biotite forms at the expense of the chlorite, and topaz, quartz and fluorite are formed at the expense of the feldspar. Major and trace element analyses show a spectrum of chemical compositions with coherent trends that support a gradational transition from the hornblende-bearing granite gneiss, through the transitional rock types to the TBQ. The mineralogical and chemical characteristics of the Renosterkop rock types are consistent with an origin by progressive greisenization of a "within plate" A- type granitoid host rock. A genetic model is proposed which involves the formation of the TBQ greisen during intense metasomatic alteration and replacement of the granite gneiss within a zone of structural weakness that provided conduits for migrating, F-rich, metal-bearing solutions, and thereby inherited the foliation and structural features present in the original granite gneiss. / Thesis (MSc)--PU vir CHO, 1987.

"The purpose of this dissertation is ... to review the economic geology of primary tin deposits and the geological factors that control grade and tonnage . The work concludes with a discussian of the implications of these geological controls on evaluation"-- Introd., p. 1

Thèse (Ph.D.R.M.)-- Université du Québec à Chicoutimi, 1992. / Résumé disponible sur Internet. CaQCU Bibliogr.: f. 187-204. Document électronique également accessible en format PDF. CaQCU

Dissertation (doctoral)--Åbo akademi, 1772. / At head of title: I.J.N. Reproduction of original from Kress Library of Business and Economics, Harvard University. Goldsmiths'-Kress no. 10859.3-1.

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Thesis (MSc.)--Stellenbosch University, 1994. / ENGLISH ABSTRACT: The NAD deposit forms part of the A-Mine Complex in the Rooiberg tin field in the north-western Transvaal. Mining started in 1986 and the mine was closed recently following a decline of tin prices and metallurgical problems with ore recovery. The deposit is hosted by the Boschoffsberg Quartzite Member of the Pretoria Group sediments and is structurally controlled within the so-called Tin Zone. Extensive alteration of the original host rocks occurred during the mineralisation event. Potassic remobilisation and redistribution appear to have taken place pervasively. The nature of the original host rock was altered to such an extent that it cannot be classified correctly. Previous workers refer to the host rock as an arkose because of its feldspathic nature. Wall rock alteration in the hanging- and foot wall of the different ore lodes (fractures) is generally similar. Very little change is observed in whole rock chemistry away from the lodes. The mineral chemistry of the ore lode minerals is indicative of fluid composition and mineralising conditions in the NAD deposit. The FeO/(FeO + MgO) ratio of tourmalines indicates deposition at a distance from the source of the mineralising fluids. Pyrite trace element chemistry differs from that of the Leeuwpoort deposit, indicating changing fluid chemistry. Contrary to previous assumptions that the carbonate present is ankerite, abundant siderite occurrences were found. Pyrite may co-precipitate with siderite under specific physico-chemical conditions. Cassiterite is generally trace element poor and relatively enriched in Fe. Hydraulic brecciation of the fractures as well as the tourmaline chemistry are strong indicators of a hydrothermal origin for the NAD deposit. However, the origin of the hydrothermal fluids is still uncertain. / AFRIKAANSE OPSOMMING: Die NAD- tinafsetting vorm dee/ van die A-Myn-kompleks in die Rooiberg tinveld in die noord-wes Transvaal. Die myn is in 1986 geopen en is onlangs gesluit weens swak tinpryse en metallurgiese ertsherwinningsprobleme. Die tinafsetting kom voor in die Boschoffsberg Kwartsiet lid van die Pretoria Groep sedimente. Dit is strukturee/ gekontroleer binne die sogenaamde Tin Sone. Vorige navorsers het na die waardgesteente as 'n arkose verwys op grand van die hoe veldspaat-inhoud. lntensiewe en uitgebreide verandering van die oorspronklike waardgesteentes het plaasgevind tydens mineralisasie. Deurdringende kalium-hermobilisering en -herverspreiding het plaasgevind. Die aard van die oorspronklike waardgesteente is egter tot so 'n mate verander, dat dit chemies nie korrek gek/assifiseer kan word nie. Wandrotsverandering van die verskil/ende ertsskeute in beide die voet- en dakgesteentes is baie soortge/yk. Die heelrotsgeochemie van die wandgesteentes verskil baie min weg van die ertsskeute af. Die mineraalchemie van die ertsskeut-minerale is aanduidend van die v/oeistofsamestelling en mineralisasietoestande van die NAD-tinafsetting. Die FeO/(FeO + MgO) verhouding van toermalyne dui daarop dat afsetting op 'n afstand vanaf die bron van die mineralisasie-vloeistowwe plaasgevind het. Die spoor-elementchemie van die NAD-piriete verskil van die piriete van die Leeuwpoort tinafsetting, wat verandering in vloeistofsamestelling aandui. In teenstelling met vorige aannames dat die karbonate in die Rooiberg tinafsettings as ankeriet bekend staan, is daar volop sideriet gevind. Piriet kristalliseer dikwels saam met sideriet onder spesifieke fisiese en chemiese toestande. Kassiteriet is meestal arm aan spoor-elemente, maar is relatief verryk in Fe. Hidroliese breksiering van die skeute en die toermalyn-chemie dui sterk op 'n hidrotermale oorsprong vir die NAD afsetting. Die bron van die vloeistowwe is nog nie definitief vasgestel nie. / Digitized at 300 dpi Colour PDF format (OCR), using ,KODAK i 1220 PLUS scanner. Digitised, Ricardo Davids on request from IBL 10 September 2013