62 research outputs found

    Possible Pleistocene hominin tracks from South Africa’s west coast

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    Two probable tracks have been identified on the ceiling of a small overhang in the Pleistocene Langebaan Formation on South Africa’s west coast. They may have been made by a hominin trackmaker. They appear to have been registered at walking speed on a level, sandy dune substrate. Three tracks, attributed to Homo sapiens, were previously identified near Langebaan in 1995, and were popularly labelled ‘Eve’s Footprints’. The new identification of possible hominin tracks near Langebaan is the second from South Africa’s west coast. This discovery adds to the sparse but growing global record of possible hominin tracks preserved in aeolianites. Significance:• Two probable fossil tracks have been identified on the ceiling of an overhang near Langebaan.• The tracks may have been made by a human walking on a level dune surface during the Pleistocene.• This discovery is the second of its kind on the west coast, and complements the 1995 identification near Langebaan of Pleistocene fossil tracks attributed to humans

    Biofilm assists recognition of avian trackways in Late Pleistocene coastal aeolianites, South Africa

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    Fourteen fossil avian tracksites have been identified in Late Pleistocene aeolianite deposits on the Cape south coast of SouthAfrica. One of these sites is unusual because of the preferential adherence of organic material (biofilm) to the natural cast tracks. This has enabled the recognition and identification of two ~6 m long, approximately parallel trackways that would otherwise not have been noticed. The trackways are visible from a distance of over 100 metres and contain 20 and 14 individual tracks, respectively. Up to 50 avian tracks are evident at this site. As the biofilm layer continues to thicken, the trackways become increasingly visible. Avian trackways of this length are globally rare.We propose that the biofilm adheres to sections with higher relief on a sedimentary surface, and that an understanding of this mode of preservation can be useful to more easily identify trackways in areas of comparable geological setting.JN

    The value of multibeam bathymetry in marine spatial planning in South Africa: A review

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    Given a growing global population and shift to embrace the blue economy, a need for marine spatial planning (MSP) has emerged in South Africa to sustainably resolve the rising conflicts over the use of marine and seabed resources and services. A well-developed marine spatial plan yields numerous ecological, social and economic benefits. These are achieved through mediating between spatially conflicting economic drivers’ interests (e.g. commercial fishing, tourism, mining), preventing their activities from compromising thresholds of an environment’s sustainability. Within the MSP framework, high-resolution geospatial datasets are required to document and describe the seabed in the highest possible detail. At any scale, integrated analysis of seabed geomorphology and habitats is anticipated to greatly improve the understanding of ecosystem functioning from a multidisciplinary perspective, whilst improving MSP procedures and management of marine space. South Africa is the first of few African countries to have an approved and implemented MSP framework, but is still somewhat behind globally in implementing large-scale regional hydroacoustic surveys to cover the country’s vast offshore territory. The deficiency of hydroacoustic surveys is perhaps due to a relative lack of funds and poor communication about the value of multibeam echo-sounder (MBES) derived data, whilst marine geoscience remains a scarce skill in the country. This review paper presents a geological perspective of MSP and explores (1) the value that seabed mapping offers MSP specifically and (2) the need to increase seabed mapping with MBES, using a recently initiated project from the South African east coast as a case study. Significance: The collected MBES data (our case study) provides unprecedented seabed detail of the complex reef habitat and adjacent areas within specific management zones of the uThukela Banks Marine Protected Area. We reveal seabed features and their spatial distribution at a scale not possible using earlier (singlebeam) seabed mapping techniques. These high-resolution data will enable a better understanding of east coast marine habitats whilst contributing to improved spatial management of areas within and around the uThukela Banks Marine Protected Area

    Late Pleistocene vertebrate trace fossils in the Goukamma Nature Reserve, Cape South Coast, South Africa

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    More than 100 Late Pleistocene trace fossil sites have been identified in aeolianites along a 275 kilometer stretch of the Cape south coast. A zone of concentration of such sites exists within the Goukamma Nature Reserve, both along the coast and along the Goukamma River. These sites provide insight into the Pleistocene fauna along the Cape south coast. Features include lion trackways, multiple elephant tracksites, a long trackway most likely attributable to Long-horned Buffalo, medium-sized carnivore tracks, avian tracks, equid tracks attributable to the giant Cape horse, numerous artiodactyl tracks, and burrow traces. The ephemeral nature of the tracksites makes regular surveys of these areas desirable, along with site documentation and trackway replication and preservation initiatives. The protected status of the area offers opportunities for geoheritage appreciation.JN

    The Provenance of Terrigenous Components in Marine Sediments Along the East Coast of Southern Africa

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    AbstractTerrestrial signals in marine sediment archives are often used for paleoclimatic reconstructions. It is therefore important to know the origin of the different terrestrial sedimentary components. The proximity to a river mouth is often the key location to determine the source. Especially in regions with strong ocean currents, such an assumption might, however, lead to considerable misinterpretations. To investigate the source of various terrigenous sediment fractions in southeastern Africa, a region with strong sediment redistribution, we have performed an extensive comparison between terrestrial material (pollen, plant lipids, detrital modes, and heavy minerals as well as bulk inorganic geochemical composition) from potential source regions and the same components in the adjacent coastal and continental shelf sediments. Onshore the proxy‐indicators reflect small‐scale diversity in sampling locations and associated environments (riverbank sediments, flood deposits, suspension loads, and soils). Nevertheless, the overall trends reflect significant environmental gradients along a SW to NE transect. We note a general comparability of the studied parameters between the continental and marine sediments regardless of their specific differences in transport and depositional characteristics. We propose that the influence of the Agulhas Current affects sediment deposition and distribution only seaward of the midshelf and that pockets of sediment remain preserved in the lee of coastal protrusions where they are protected from erosion. This study provides the essential prerequisite to allow the attribution of temporal variations of compositional changes in marine sediment cores to environmental changes in southeastern Africa

    The Pleistocene fauna of the Cape south coast revealed through ichnology at two localities

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    East of Still Bay on the Cape south coast of South Africa lies a rugged, remote stretch of sea cliffs that expose Late Pleistocene aeolianites. A zone of dense concentration of fossil tracks occurs within this area. Two large rocks, which we call Roberts Rock and Megafauna Rock, were identified ~400 metres apart. These rocks contained a variety of trackways, individual tracks, burrow traces and invertebrate trace fossils on multiple bedding planes. Both rocks were found ex situ, but their context could be determined. Roberts Rock has subsequently slid into the ocean, and Megafauna Rock lies at the base of a coastal cliff. Probable trackmakers include elephant, long-horned buffalo, giant Cape horse, rhinoceros, medium and small artiodactyls, golden mole, birds and invertebrates. Dating studies at an adjacent site, which is comparable to the stratigraphy described here, indicate that both rocks were most likely deposited in Marine Isotope Stage 5e (~128–116 ka). Analysis and description of these tracksites confirms the potential of ichnology to complement the skeletal fossil record and to enhance the understanding of Pleistocene life in southern Africa. The ephemeral nature of such tracksites makes repeated visits to this coastline desirable, both to monitor the fate of known sites and to search for newly exposed trace fossil surfaces. Significance: • Roberts Rock and Megafauna Rock are two remarkable fossil tracksites on the Cape south coast, which contain tracks of four members of the Late Pleistocene megafauna. They provide a glimpse of Pleistocene dune life and suggest an area teeming with large mammals. • These tracks were made on dune surfaces near an interface between the grassland of the Palaeo-Agulhas Plain and the inland Fynbos–Strandveld–Renosterveld. Faunal assemblages from both vegetation zones might therefore be recorded. • The trace fossil record and body fossil record both have inherent biases, but have the potential to independently provide complementary information on palaeofaunal composition. • The two rocks have provided the first South African records of fossil elephant tracks (as first described by Dave Roberts and colleagues in 2008), the first rhinoceros track and the first extinct giant Cape horse track, and track evidence of the extinct long-horned buffalo. • Roberts Rock has slumped into the ocean, and it provides an example of the fate of many exposed tracksites. Conversely, new sites frequently become exposed. This scenario stresses the need for regular ichnological surveys along this track-rich coastline to monitor existing sites and to search for new sites

    A synthesis of three decades of socio-ecological change in False Bay, South Africa: setting the scene for multidisciplinary research and management

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    Over the past three decades, marine resource management has shifted conceptually from top-down sectoral approaches towards the more systems-oriented multi-stakeholder frameworks of integrated coastal management and ecosystem-based conservation. However, the successful implementation of such frameworks is commonly hindered by a lack of cross-disciplinary knowledge transfer, especially between natural and social sciences. This review represents a holistic synthesis of three decades of change in the oceanography, biology and human dimension of False Bay, South Africa. The productivity of marine life in this bay and its close vicinity to the steadily growing metropolis of Cape Town have led to its socio-economic significance throughout history. Considerable research has highlighted shifts driven by climate change, human population growth, serial overfishing, and coastal development. Upwelling-inducing winds have increased in the region, leading to cooling and likely to nutrient enrichment of the bay. Subsequently the distributions of key components of the marine ecosystem have shifted eastward, including kelp, rock lobsters, seabirds, pelagic fish, and several alien invasive species. Increasing sea level and exposure to storm surges contribute to coastal erosion of the sandy shorelines in the bay, causing losses in coastal infrastructure and posing risk to coastal developments. Since the 1980s, the human population of Cape Town has doubled, and with it pollution has amplified. Overfishing has led to drastic declines in the catches of numerous commercially and recreationally targeted fish, and illegal fishing is widespread. The tourism value of the bay contributes substantially to the country’s economy, and whale watching, shark-cage diving and water sports have become important sources of revenue. Compliance with fisheries and environmental regulations would benefit from a systems-oriented approach whereby coastal systems are managed holistically, embracing both social and ecological goals. In this context, we synthesize knowledge and provide recommendations for multidisciplinary research and monitoring to achieve a better balance between developmental and environmental agendas.https://www.elementascience.orgam2020Mammal Research Institut
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