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Typescript (Photocopy) / Includes bibliographical references (leaves [181]-206) / vi, 207, [16] leaves, 16 p. of plates : ill., maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Geophysics, 1989

Thesis (Ph. D.)--University of Adelaide, Dept. of Geology and Geophysics, 1987. / Includes bibliographical references (leaves 275-290).

Thèse (D.R.Min.) -- Université du Québec à Chicoutimi, 2001. / Bibliogr.: f. 237-249. Document électronique également accessible en format PDF. CaQCU

The study area is located between Loskop Dam and the town of Groblersdal, on the southeastern flank of the Dennilton dome, and is underlain by lithologies of the Pretoria Group, Bushveld Complex mafics and ultramafics and acid lavas that resort under the Rooiberg felsites. Field work comprised of geological mapping, soil-, hard-rock- and stream sediment geochemistry, various geophysical techniques and diamond drilling. The rocktypes that resembles the Rustenburg Layered Suite on the farm Rietfontein 70JS is subdivided into a Mixed Zone, Critical Zone and Main Zone, on grounds of geochemical and certain geophysical attributes. The Mixed Zone that overlies the Bushveld Complex floor-rocks, is furthermore separated into an i) Lower-, ii) Middle- and, iii) Upper Unit. The Lower Unit of the Mixed Zone consists primarily of magnetite-gabbros, iron-rich pegmatites, harzburgites and feldspathic pyroxenites. The Fe-rich constituents of this stratigraphic horizon generates a pronounced magnetic anomaly within the study area. On the basis of; amongst other parameters, Zr/Rb and Sr/Al₂0₃ ratios, the magnetite-gabbros are postulated to conform to lithotypes in the vicinity of magnetite layers 8 to 14 of Upper Zone Subzone B in a normal Bushveld Complex stratigraphical scenario. Similarly, it is argued that the feldspathic pyroxenites and norites that display elevated chromium values are analogues to normal Critical Zone rocktypes of the Rustenburg Layered Snite. A more elaborate and precise stratigraphic correlation for the Critical zone was, however, not possible. It is advocated that a volume imbalance was created by the hot, ascending mafic magmas of the intruding Bushveld Complex, resulting in the updoming of certain prevailing basement features such as the Dennilton Dome. In addition to this ideology, it is proposed that the Mineral Range Fragment is in fact a large xenolith underlain by mafics, after being detached from the Dennilton Dome during the intrusion event. Evidence generated by this study unequivocally indicate that the potential for viable PGE's, Ni, Cu and Au within a Merensky Reef- type configuration or a Plat Reef-type scenario under a relatively thin veneer of acid Bushveld Complex roof-rocks on the eastern flank of the Dennilton Dome, appears feasible.

Observed stratigraphic variations within the Salem synclinorium in the Valley and Ridge Province of the southern Appalachians are part of a larger basinal setting. The basal conglomerate of the Ordovician Bays Formation is restricted to the limb of the synclinorium reflecting a regional trend of coarser sedimentation nearest the Taconic sediment source. Ordovician/Silurian and Silurian/Devonian unconformities have removed more section from the southern portion of the synclinorium which has been interpreted as evidence of a more landward setting for this area. Previous interpretations of these coarser sediments and unconformities theorized the synclinorium was a unique depositional basin active throughout Paleozoic time. The relationship between veins, fractures, slickensides, oblique-slip faults and thrusts in a riverbed exposure within the southwestern portion of the Salem synclinorium, offers a structural model for the Salem synclinorium. Thrusting induced extensional fractures and veins. Oblique-slip faults which cut the thrusts may have nucleated on these preexisting extensional features. On a larger scale, extensive secondary fracturing between faults may have produced the larger fault zones observed in the synclinorium. Although stratigraphic thickness variations within the synclinorium correspond to observed fold wavelength variations, faulting disrupts many of these folds and distorts the wavelength estimate. Faulting, not folding, is the dominant structural process. Ramp size and horse blocks are theorized to control fold wavelength within the Salem synclinorium. / M.S.

Bibliography: leaves 275-290 / xviiii [i.e. xvix], 352 leaves : ill ; 31 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Geophysics, 1987