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dc.contributor.advisorTordiffe, E. A. W.
dc.contributor.authorStrauss, Schalk Willem
dc.date.accessioned2018-08-21T10:50:12Z
dc.date.available2018-08-21T10:50:12Z
dc.date.issued1986-01
dc.identifier.urihttp://hdl.handle.net/11660/9163
dc.description.abstractEnglish: The thick soil cover over most of the felsic rocks of the Bushveld Complex, presents a major obstacle in the search for Sn deposits. In order to define those parameters that might reflect the presence of Sn mineralisation under such conditions, an orientation study was made of soil geochemical parameters in an area of known Sn mineralisation. The area chosen was the farm Vlaklaagte 221JR in the central Bushveld Complex where quartz-vein greisen type Sn mineralisation is known to exist. The soils overlying the mineralisation are latosols in which three periods of soiI formation can be identified. A pebble layer representing an unconformity in the soiI profiles, with transported soils on top and residual soils or palaeo-colluvium below, has a dominating influence on the mineralogical and geochemical dispersion patterns in the soils. A consequence is that the B horizon, to which most attention is usually paid during exploration, presents an entirely unsatisfactory sampling medium due to its development in either the transported or residual soil. Mineralogical and geochemical data were used to identify the various weathering cycles and the relationships between primary and secondary anomalies. Special attention was given to the behaviour of Sn, Cu, Mo, Rb, Sr and Ba, which were then used to establish possible guidelines for exploration. Where Sn is used as a pathfinder element the pebble layer yielded the best results as a sampling medium. A combination of 1) the Sn concentration in a bulk sample in the lower section of the lower pebble layer, 2) the ratio of the Sn concentrations (using bulk samples) between the lower section of the lower pebble layer and the residual soils and 3) the distribution patterns of cassiterite grain-size populatlons in the lower pebble layer (lower section) proved to be the most sensitive means for exploration (provided that the Sn is associated with cassiterite and that the pebble layer is in direct contact with the residual soils). Copper and Mo are also very sensitive pathfinder elements but their source is not necessarily the same as for Sn. They are, however, always closely associated with the Sn deposits and can therefore be used effectively in tracing associated mineralisation which wilI eventually lead to the Sn deposits. The most sensitive parameters proved to be a combination of the Cu or Mo concentrations In the siIt-clay fraction in the lower part of the C horizon and their concentrations in individual goethite pellets from the lower section of the lower pebble layer. Rubidium/Sr and Rb/Ba ratios are useful in identifying highly differentiated or metasomatic zones with which Sn deposits are associated. The silt-clay fraction in the lower part of the C horizon is recommended for the latter. The weathering cycles and the elemental dispersion patterns are found to be dependant on the following factors: The palaeo- and present climatic conditions. The topography (palaeo- and present). The primary minerals with which the elements are associated and the weatherabiIIty of the minerals. The predominant end minerals in the soils and their elemental association. The mobility of the elements under different Eh-pH conditions.en_ZA
dc.description.abstractAfrikaans: Die dik grondbedekking oor groot gedeeltes van die felsiese gesteentes in die Bosveld Kompleks, bied 'n groot hindernis in die soektog na Sn afsettings. In 'n poging om hierdie hindernis te oorbrug is 'n studie van geochemiese parameters in gronde in 'n gebied van bekende Sn mineralisasie gedoen. Die gebied wat gekies is, is die plaas Vlaklaagte 221 JR in die sentrale Bosveldkompleks waar die bestaan van kwartsaar-greisentipe Sn-mineralisasie bekend is. Gronde wat die mineralisasie oorlê is latosols waarin drie periodes van grondvorming geidentifiseer kan word. 'n Rolsteenlaag wat nonreëlmatigheid in die gronde verteenwoordig, met aangevoerde gronde bo-op en residuele gronde of paleo-kolIuvium onder, het die dominerende invloed op die mineralogiese en geochemlese verstrooiingspatrone in die gronde. 'n GevoIg hiervan is dat die B-horison, waaraan normaalweg die meeste aandag gedurende eksplorasie geskenk word, ongeskik as 'n monsteringsmedium is, weens die ontwikkeIing daarvan in óf die aangevoerde óf die residuele gronde. Mineralogiese en geochemiese data is gebruik om die verweringssiklus en die verwantskappe tussen primêre en sekondêre anomalleë vas te stel. Spesiale aandag is geskenk aan die gedrag van Sn, Cu, Mo, Rb, Sr en Ba en moontlike riglyne is vir eksplorasie bepaaI. Waar Sn gebruik is as 'n padvinderelement, het die rolsteenlaag die beste resultate as 'n monstermedium verseker. 'n Kombinasie van 1) die Sn konsentrasie in heelmonsters in die onderste gedeelte van die onderste rolsteenlaag, 2) die verhouding van Sn konsentrasies (heelmonsters) tussen die onderste gedeelte van die onderste rolsteenlaag en die residuele gronde en 3) die verspreidingspatrone in korrelgrootte popuiasles van kassiteriet in die onderste gedeelte van die onderste rolsteenlaag, blyk die mees sensitiewe metode te wees (met die voorbehoud dat die Sn geassosieer is met kassiteriet en dat die rolsteenlaag in direkte kontak met die residuele gronde is). Koper en Mo Is ook baie sensitiewe padvinderelemente maar hul bron is nie noodwendig dieselfde as vir Sn nie. Dit is egter altyd bale nou geassosieer met Sn afsettings en kan dus effektief gebruik word in die opspoor van geassosieerde mineralisasie wat dan uiteindelik na die Sn afsettings sal lei. Die mees sensitiewe parameters blyk te wees 'n kombinasie van die Cu of Mo konsentrasies in die modder en kiel fraksie in die onderste gedeelte van die C horison en hul konsentrasies in individuele goethiet piIle vanuit die onderste gedeelte van die onderste rolsteenlaag. Rubidium/Sr en Rb/Ba verhoudings is baie bruikbaar in die identifikasie van hoogs gedifferensieerde of gemetasomatiseerde sones, waarmee die Sn afsettings normaalweg geassosieer is. Die modder plus kiel fraksie in die onderste gedeelte van die C horison word aanbeveeI in Iaasgenoemde gevaI. Die verwerlngssiklusse en die elementverspreidingspatrone is afhanklik van die volgende faktore: Die paleo- en huidige klimaatstoestande. Die topografie (paleo- en huidig). Die primêre minerale waarmee die elemente geassosieer is en hul weerstand teen verwering. Die dominerende eindminerale in die gronde en hul elementassosiasie. Die mobiliteit van die elemente onder verskillende Eh-pH toestande.en_ZA
dc.language.isoenen_ZA
dc.publisherUniversity of the Free Stateen_ZA
dc.subjectLatosolsen_ZA
dc.subjectSn mineralisationen_ZA
dc.subjectQuartz-vein greisenen_ZA
dc.subjectSn depositsen_ZA
dc.subjectDissertation (M.Sc. (Geology))--University of the Free State, 1986en_ZA
dc.titleAn evaluation of geochemical parameters for tin exploration in soil covered areas in the central Bushveld complexen_ZA
dc.typeDissertationen_ZA
dc.rights.holderUniversity of the Free Stateen_ZA


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