M.Sc. (Geology) / The study area is subdivided into seven tectonic domains, viz. Bandelierkop, Southern Beit Bridge Complex, Alldays, Hestern Transvaal, Soutpansberg, Waterberg and Lebombo domains. The Bandelierkop domain comprises the Southern Marginal Zone of the Limpopo Belt (Bdl) and the northern portion of the Kaapvaal craton (Bd2). Bdl is characterized by the presence of highly disrupted xenoliths of pelitic and mafic supracrustal rocks distributed in a "s ea " of granitic ·material. This contrasts with the much bigger supracrustal xenoliths in Bd2, i.e. the greenstone belt relicts. The granulite facies rocks of Bdl may have been upthrust roughly from south to north along one or more south-dipping thrust faults soling into a gently-dipping to flatlying basal shear zone. Since this model reveals the existence of the Kaapvaal craton partly on edge, the progressively higher grade of regional metamorphism (from greenschist to granulite facies) encountered in the Bandelierkop domain, from south (Bd2) to north (Bdl), could express the transition from upper crust to lower crust as exposed on the present land surface. The structural trends found in Bdl and Bd2 are not strictly confined to either area, and some overlapping exists. The most distinct structural trend in Bdl is a west-northwest fold trend, a northeast fold trend also being recognized in the eastern portion of Bdl. Bd2 exhibits f~ld trends varying from west-northwest to northeast in orientation; in this area there is ample evidence for the later nature of the northwest- to west-northwest oriented folding event. The east-northeast- to northeast folding is con~ dered to represent an event independent of the effect of deformation of the Kudus River shear zone to which this folding was previously thought to be related.The portion of the Central Zone of the Limpopo Belt falling within South African territory comprises the Alldays and Southern Beit Br_idge Compl ex (SBBCd) doma tn s., There exists a marked contrast between the roughly north trending fold trends of the Alldays domain and the east-northeast fold structure of the southernmost part of the Central Zone, the SBBCd. The relatively gentle plunges of the fold structure of the Alldays domain may have accentuated the size of the regional folds in this region. The SBBCd occupies a narrow east-northeast oriented strip extending immediately south of the Alldays domain, where tightly folded gneisses and metasedim~nts are exposed. all strata are strongly aligned in the regionally extensive eastnortheast direction. A contrasting difference between the SBBCd and the surrounding Precambrian terranes is clear, as the former domain conveys a relatively higher strain; this evidence of heterogeneous strain suggests that the SBBCd represents a shear zone. The shearing movement may have been of thrust type, consistent with the thrust model referred to above, and the SBBCd may be regarded as the thrust plane. In'iiew of the steeply-dipping, south-southwest oriented fold axes known to exist along part of the SBBCd (area south of Messina), it would appear that, at least in that area, the thrust movement would have been towards the north-northeast. A late, involved history of deformation followed in the SBBCd, during which one or more episodes of wrench-type movement may have taken place. The Soutpansberg domain is a relatively narrow and long fault zone of Proterozoic to Phanerozoic age that separates 'mobile belt' environment to the north, from 'cratonic' environment to the south. A linked fault system characterized by south-dipping, normal listric faults soling into ? gently-dipping major detachment surface may account for the structural pattern of this domain. The thrust system referred to above, which developed earlier in the geological history of the region along the Limpopo Belt - Kaapvaal craton boundary, may have controlled the late extensional displacement in the Soutpansberg domain. The overall structure of the Waterberg domain would seem to be controlled by the superimposition of northeastand northwest oriented gentle folds and, with the exception of locally intense deformation in the early Waterberg basin, would appear to have developed on a relatively stable portion of crust. The structure of the Lebombo domain is characterized by a north-south striking monocline with gentle east dip. Most of the lineaments inferred from the aeromagnetic survey of the study area originate from dyke intrusions. Faulting, fracturing and shearing are less clearly manifested in the pattern of the aeromagnetic contour maps, instead they are better correlated with the lineaments inferre~ from LANDSAT imagery and from the drainage patterns of the region.

Mara Lake, British Columbia, straddles the boundary between the Monashee Group on the east and the Mount Ida Group on the west. Both groups of rock have experienced four phases of deformation. Phases one and two are tight and recumbent, trending to the north and to the west respectively. Phases three and four are open to close and upright, trending northwest and northeast respectively. Second phase deformation includes large scale tectonic slides which separate limbs of major folds. These slide surfaces are folded by third and fourth phase structures and outline domal outcrop patterns. Peak metamorphism accompanied and followed phase two. Metamorphic grade is related to position within the second phase structure, increasing downward from greenschist to amphibolite facies. Greenschist conditions accompanied phase three while hydrothermal alteration characterizes phase four. Brittle fracturing and local faulting along a northeasterly trend followed phase four. Abrupt changes in metamorphic grade found at the northern end of Mara Lake are related to these late faults. Correlation of lithologies across the southern end of Mara Lake and the similar structural sequences indicate that no stratigraphic or structural distinction is necessary between the Mount Ida Group and the Monashee Group. On a regional scale similar structural sequences are observed in other areas of the Shuswap Metamorphic Complex. Microscopic deformation features are common in many mineral phases in the Mara Lake area. Amphibole rarely shows evidence of plastic deformation. To examine this apparent high strength characteristic, fifty samples of hornblendite (AM-2) were deformed in a large, solid-medium Griggs-type apparatus at 700° to 1000°C at strain rates from 10⁻⁴/sec to 10⁻⁶/sec and at 10 kb confining pressure. Talc, pyrophyl lite, and platinum jacketing were used to yary water content. From 700° to 850°C both mechanical twins (101) and translation glide (100) were observed. Twin development appears to be favored over glide at higher confining pressures, lower temperatures, and higher strain rate. Above 850°C subgrain development and recrystallization occur just prior to melting. A flow law, Є = ~ 1.5 x 10⁻¹ exp (-38/RT)σ[sup 4.8] describes steady state deformation from 750° to 910°C under wet conditions. Decreasing water and temperature are accompanied by increasing n values and perhaps increasing activation energy. At 750°C under dry conditions an exponential relationship, Є = 53 exp (.23 σ) best fits the data. From 910° to 950°C the amphibole structure "hardens" such that strain rate remains constant for a given load. This hardening is interpreted to be related to oxidation and distortion within the lattice. Uncertainty regarding the activation energy precludes effective extrapolation of the data to "geologic" strain rates. A tentative comparison of amphibole and quartz data reveals an order of magnitude difference in flow stress, suggesting that quartz will yield plastically before amphibole. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

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Thesis (Ph.D.)--University of Melbourne, School of Earth Sciences, 2007. / Typescript. Includes bibliographical references (leaves 197-215).

Thesis (MS)--Montana State University--Bozeman, 2008. / Typescript. Chairperson, Graduate Committee: David R. Lageson. Includes bibliographical references (leaves 85-93).

Thesis (M.S.)--Humboldt State University, 2008. / Two folded maps in pocket. Includes bibliographical references (leaves 90-95). Also available via Humboldt Digital Scholar.

Thesis (M. Phil.)--University of Hong Kong, 2005. / Title proper from title frame. Also available in printed format.