A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science, Faculty of Science University of the Witwatersrand, Johannesburg 2018 / Canteen Kopje has yielded rare in-situ assemblages of the Fauresmith, a poorly defined industry often associated with the later Acheulean. The Fauresmith contains precocious developments in technology as early as ~0.5 Ma–features which only become widespread in the ensuing Middle Stone Age. The Fauresmith as a regional industry provides insight into technological practices during the period of significant behavioural diversification associated with archaic Homo sapiens. Previous excavations were conducted with relatively low spatial resolution. A new excavation, Pit 4 West, was conducted to investigate the spatial, stratigraphic and contextual association of the Fauresmith horizon in more detail. A multi-disciplinary fineresolution geoarchaeological approach was applied. A nuanced assessment of the Fauresmith’s context was developed, with macroscopic and microscopic analyses allowing for the identification of site formation processes influencing assemblages. The artefact sample size for the site was increased and the presence of diagnostic tools has aided in formally defining the Fauresmith at Canteen Kopje. / XL2019

No description available.

This thesis investigates the origin, sedimentological characteristics, and paleoglacial significance of large latero-frontal moraines and moraine-dammed glacial lakes and their potential to generate glacial lake outburst flood (GLOF) events in the Cordillera Blanca, Perú and Iceland. This topic is particularly important as the potential for GLOF events in high altitude regions is increasing as ongoing global climate warming causes rapid glacier recession and the growth of lakes impounded by unstable moraines. The first chapter of this thesis introduces the characteristics of moraine dammed lakes and GLOFs and provides details of the study areas in Perú and Iceland that were selected for this work (Chapter 1). Chapter 2 investigates the glacial history of the Cordillera Blanca, Perú through the compilation, mapping, and analysis of dated moraines in the region. The formation of moraines by different glaciers in the same region at approximately the same time is interpreted to indicate a period of regional climate conditions that were favourable for glacier expansion and/or equilibrium. Six stages of glacial activity are identified from this analysis, ranging in age from older than 35 thousand years (Stage 1) to modern (Stage 6). The third chapter of this thesis identifies the geomorphic and sedimentologic characteristics of a moraine-dammed supraglacial lake (Llaca Lake) in the Cordillera Blanca, Perú. The combined use of imagery collected with an uncrewed-aerial vehicle (UAV), field sedimentological observations and geomorphological mapping allowed the creation of a landsystem model that summarizes the current geomorphic and sedimentologic environment of Llaca Lake (Chapter 3). This is the first study to describe the landform-sediment assemblages in a tropical moraine-dammed supraglacial lake and provides a framework for further landsystem analysis of growing supraglacial lakes that are at risk of GLOF events. The fourth chapter of this thesis describes the sedimentary architecture of the eastern lateral moraine of Gígjökull in southern Iceland. An uncrewed-aerial vehicle was used to acquire high resolution photographs of an exposure through the lateral moraine that allowed the identification of seven lithofacies types and three lithofacies associations. Documentation of the sedimentary architecture of the eastern lateral moraine of Gígjökull enhances understanding of moraine development and the identification of areas of hydrogeological weakness that can reduce the structural integrity of the moraine. The research findings presented in this thesis utilize a glacial sedimentological and geomorphological approach to investigating the relationship between current and past glacial processes in the study areas, and the role that these processes play in determining the characteristics and stability of large ice marginal moraines that impound glacial lakes. This work also furthers our understanding of the dynamic surface processes at work in high altitude regions such as the Cordillera Blanca. Identifying and determining the relationships between current and past processes, sediments and landforms will enhance understanding of the role of large moraines damming glacial lakes in other high-altitude regions such as the Himalayas, British Columbia, Patagonia, and New Zealand and the associated risk of GLOF events. / Thesis / Doctor of Science (PhD)

No description available.

The ~2 km-thick Late Triassic Sugarloaf Arkose is the basal unit of the half-graben Deerfield basin, Massachusetts. Valley-river, piedmont-river, and alluvial-fan depositional facies within the arkose are defined by paleocurrent data and style of sedimentation. The valley rivers flowed from northeast to southwest, and the facies is present from the bottom to the top of the formation. Piedmont rivers built a megafan eastward into the basin, beginning about in the middle of the arkose. The local alluvial fan built from east to west in the upper-third of the formation. The petrology of the medium sand and conglomerate was used to delineate the source areas for each facies. The medium sand in the valley rivers is mostly granite and granite gneiss fragments, coarsely-polycrystalline quartz grains, and twinned plagioclase. This assemblage is a mixture of granite from continental basement uplift, granite gneiss from a dissected magmatic arc, and phyllites and schist from a recycled collision orogen. The medium sand in the piedmont-river facies lacks granite fragments, and untwinned plagioclase is more abundant than twinned: the provenance is continental basement uplift and recycled collision orogen. The alluvial-fan provenance is similar to the valley rivers, combining recycled collision orogen and dissected magmatic arc. Unlike the valley rivers, granite gneiss and untwinned plagioclase in the alluvial fan are dominant over granite and twinned plagioclase. Quartz provenance in the three facies was granite, trending to granite gneiss in the piedmont-river and alluvial-fan facies. In all facies, plagioclase feldspar is more common than K-feldspar in the medium sand. The conglomerate pebbles, however, are dominated by K-feldspar, most likely due to erosion of pegmatites in the source terrane. Gray quartzite, white and translucent varieties of quartz, and pink granitoid pebbles are also common. The post-depositional diagenesis of the Sugarloaf Arkose affects provenance determination. Diagenetic events include: hematite grain coats, mechanical compaction, albitization of feldspars, albite and quartz overgrowths, authigenic hematite cement, carbonate cement, and illite replacement of feldspars. Within the dry-dominated monsoonal paleoclimate, each facies formed in response to tectonism. The initial appearance of each facies is used to determine the timing of tectonic events. The valley rivers flowed from the northeast in an early NNE-SSW-trending ‘sag’ basin, associated with minor normal faulting. The initial appearance of the east-flowing piedmont rivers about half way up the section implies an early, down to the west, basin-bounding normal fault, which formed perpendicular to N70E-S70E extension. This fault propagated, and, on reaching the northeast corner of the basin, the alluvial fan built to the west off the fault scarp. The Amherst block is a relay ramp between basin-bounding faults in the Deerfield and Hartford basins. Linkage of the two basin-bounding faults through the Amherst block created an integrated basin linking the Triassic strata in the early Hartford and Deerfield basins, and may have caused the unconformity present at the top of the arkose.

Tropical Storm Irene’s most extreme rainfall resulted in record-breaking sediment loads from upland tributaries to the Connecticut River. However, was the event exceptional with respect to resultant deposition downstream? Off-river waterbodies to the Lower Connecticut River, such as cut-off meanders and blocked valley lakes, are a particularly important floodplain environment, which have been shown to serve as a focal point for the trapping of sediment and associated contaminants. This study evaluates the relative role of extreme events like Tropical Storm Irene in infilling these off-river environments. To meet this objective we compare the magnitude and composition of resultant sedimentation from Irene to that observed following the 2011 and 2013 spring freshets. Tropical Storm Irene deposits were identified as compositionally distinct, grey layers that were relatively inorganic compared to sediments deposited by the annual spring freshet. Sediment within the Irene deposit was enriched in elemental potassium and depleted in zircon, a finding consistent with being enriched by glacigenic lacustrine and till sediments. Decreased mercury levels in the Irene deposits suggest that this event served to cap highly contaminated, industrial era sediment with a layer of relatively clean, fine-grained silt and clay. Resampling of these waterbodies in Fall 2012 revealed preservation of the 2-3 cm thick Irene deposit as well as 3-4 cm of more recent sediments deposited on top of this event. Sediment contributions from rare events, like Tropical Storm Irene, were found to be less influential than the annual spring freshet in the long-term infilling of waterbodies along the Lower Connecticut River. However, sediments from Irene are compositionally unique and serve to highlight the importance of this event in removing glacially derived fines from the river’s upland catchments.

No description available.

Understanding modern features allows for their use as analogues for understanding the environments of the past and even environments on other planetary bodies. This study uses Ground-Penetrating Radar (GPR) to image the near surface sedimentary structures on a large linear dune in the northern Namib Sand Sea and image the sedimentary structure of an auxiliary dune. GPR data was collected using a 200 MHz antenna with a continuous scan method and was processed by removing direct arrival, gain balancing, migration and more which produced the highest resolution imagery from this region to date. Large dune data was analyzed to determine depositional process for different sedimentary patterns observed. Auxiliary dune data was analyzed to determine dune type and migration direction. Our results indicate five sedimentary process zones in the near surface of the large primary dune. These processes include motion of the dune crest as well as different phases of superimposed dune deposition. It is evident from our interpretation that there have been at least two phases of superimposed dune deposition separated by an erosional process boundary. These phases of deposition have produced a reversed succession of strata on opposing sides of the dune with deposits of 3D superimposed dunes beneath 2D superimposed dune deposits on the west and deposits of 2D superimposed dunes beneath 3D superimposed dune deposits on the east. This suggests a reversal of wind environment in the region in the recent past and could provide insight into the building and stability of linear dunes on Earth. Our results also indicate that the auxiliary study dune is oblique in nature with migration to the north-northeast and that it and other similar dunes in the vicinity are formed because of their proximity to Tsondab Vlei. The apparent dependence of these smaller scale features on interruptions in the dunefield like Tsondab Vlei suggest that the normal wind patterns within the dunefield are a combination of the regional wind patterns with significant influence from the large linear dunes themselves.

<p> The Wapiabi-Belly River transition and the Belly River Formation was studied in detail in seven sections in the Ghost Dam spillway, near Ghost Dam,Alberta. Units in the lowest portion of the outcrop (Wapiabi) are characterized by sandy mudstones, often coarsening upwards. The mudstones are overlain by storm generated, hummocky cross-stratified sandstones and beach deposits. The vertical sequence represents a shallowing trend. </p> <p> Above the beach deposits lie sandstone and interbedded mudstone-sandstone units (Belly River) deposited in a meandering river environment. Sandstones thicker than approximately two metres were deposited as point bars, show sedimentary structures representative of channels and often pinch out, or laterally interfinger with mudstone. Interbedded mudstone-sandstone units were formed during flood stances. These overbank deposits are classified as either proximal or distal components of the meandering river system. </p> <p> Several marine trace fossils, (Macaronichnus segregatis, Skolithos, Planolites, Chondrites, Teichichnus, and Ophiomorpha nodasa), found in the Belly River rocks suggest a minor marine influence on the river system. </p> <p> The river system is inferred to have been moderately to highly sinuous and comparable in discharge to the Humber and Credit Rivers (Ontario). </p> <p> Petrographic studies show that point bar sandstones are often characterized by fining upward trends and an upward increase in the proportion of carbonate cement. </p> <p> Distal overbank deposits are normally overlain by proximal overbank deposits which inturn are overlain by either point bars or distal overbank deposits. Point bar deposits may be overlain by either proximal or distal overbank. </p> / Thesis / Bachelor of Science (BSc)

<p>The Long Rapids Formation in the Moose River Basin of northern Ontario is Upper Devonian in age and can be correlated with similar shale deposits in the Michigan, Appalachian, and Illinois Basins . The southern Ontario equivalent to the Long Rapids Formation is the Kettle Point Formation. </p> <p> The Long Rapids Formation is a marine black shale deposited predominantly under depleted oxygen conditions. Large amounts of marine organic matter from the water column and from terrestrial sources accumulated in reducing bottom waters with little recycling to produce brown to black, organic-rich sediments . The depositional basin was stratified, and anoxic bottom waters and oxic surface waters were separated by a pycnocline. The position of the pycnocline (or the absence of it) dictated the type of sediment deposited, and the relative depth of the pycnocline to the sediment-water interface was more important than the absolute depth of the water column. The Moose River Basin in Late Devonian times was located on the Laurasian Continent in an area experiencing tropical conditions and was affected by a period of transgression following the Acadian Orogeny. The black shales in the Long Rapids Formation represent a period of transgression of the large epicontinental Catskill Sea, whereas the green-grey mudstones and carbonates represent periods of minor eustatic changes. </p> <p> Dark-coloured facies with abundant bioturbation are overlain by lighter-coloured facies. Bioturbation is variable in the less abundant green-grey mudstone and carbonate facies, and were also low in organic matter. The ichnofauna suite Chondrites-Planolites-Zoophycos-Alcyonidiopsis-(?Teichichnus) represents an oxygen-minimum ichnofacies found predominantly in dark shale facies. As more oxygen was introduced to the sediment-water interface, more permanent burrow structures were constructed such as Teichichnus, Terebellina, ?Cylindrichnus, Skolithos, and Ichnogenus "A" in the green-grey mudstones and carbonates. As well, body fossils were more commonly found in those facies. The Leiorhynchus brachiopod fauna in the dark-coloured shales probably represents a sparse epifauna living in poorly oxygenated or temporarily oxic conditions in a basinal or open-shelf environment. </p> / Thesis / Master of Science (MSc)