Browsing by Subject "Holocene"

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    A comparison of charcoal and stable carbon isotope results for the Caledon River Valley, southern Africa, for the period 13 500 - 5 000 yr BP
    (South African Archaeological Society, 2003) Esterhuysen, A B; Smith, J M
    The terminal Pleistocene to middle Holocene in the interior of southern Africa is characterized by a warming trend culminating in temperatures similar to or greater than those of today. However, as more refined palaeoenvironmental sequences are produced it becomes increasingly evident that pronounced temperature fluctuations occurred during this period Studies at two contemporaneous archaeological sites in the Caledon River Valley (29?13 'S; 27?28 'E and 29?28'5; 2 7?46 'E) have yielded a proxy climatic history for the period between 13 500 and 5000 yr BP Two independent palaeoenvironmental studies, a charcoal andfaunal stable carbon isotope analysis, were carried out at each site. A comparison of the results of these two analyses indicates that more than one temperature fluctuation occurred during the terminal Pleistocene to the middle Holocene. The record suggests warming to warm temperatures at ca. 12 600-13 000 yr BP (12 925 cal. yr BP), ca. 10 000 yr BP (41 134 cal. yr BP), ca. 8500-8000 yr BP (-9051 cal. yr BP), and ca. 6000-5970 yr BP (-7000 cal. yr BP), while cooler conditions prevailed at ca. 9000-8800 yr BP (10 004 cal. yr BP) and ca. 7300-7000 yr BP (-8000 cal. yr BP). These fluctuations are compared to those recorded elsewhere, in particular those that correspond to the ca. 7300-7000 yr BP event.
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    The exploitation of fish during the Holocene in the South-Western Cape, South Africa
    (1996) Poggenpoel, Cedric Alan; Parkington, John
    This thesis describes the fish remains recovered from a number of sites in three different localities in South Africa; Elands Bay and Langebaan Lagoon on the west coast, and False Bay on the Cape Peninsula. Chapter One is an introductory account of ichthyology, its usefulness in archaeological research and the range of analytical work done in South Africa, whilst Chapter Two is an attempt to show the history and development of the study of fish bones recovered from prehistoric sites in South Africa. Chapter Three gives an account of the southern Oceans, the Benguela Current and fishing habitats. Chapters Four and Five give accounts of the fishing habitats within the Elands Bay area and of the identification and interpretation of fish assemblages excavated at four sites and their implications in relation to habitat and palaeoenvironmental changes at Elands Bay. This information is used first to show that the presence or absence of certain species and the size of those species in the archaeological record can be used as an alternative means to interpret late Pleistocene and Holocene sea level fluctuations and to understand to what extent local fishing habitats have been influenced by those changes. An important observation made was the relative surplus or deficit of vertebrae compared to cranial parts through the sequence. The over-representation or under-representation of fish vertebrae in the fish assemblages points to changes in the procurement strategy employed. The consistency between cranial:vertebral ratios through the site sequences suggests that these patterns are related to both location and processing techniques. Chapter Six reviews the ecology of the Langebaan Lagoon, the identification of fish assemblages from three open midden stations; Stotbergfontein on the shores of the lagoon and Paternoster and Duiker Eiland which are located on the Vredenberg peninsula. Chapter Seven gives a short overview of the modern fishing situation at False Bay and discusses the fish assemblages from Smitswinkelbaai Cave and Rooiels Cave in the False Bay area. Chapter Eight deals with the archaeological evidence for fishing equipment and the depiction of fishing scenes in the rock art of South Africa and addresses the historical evidence for indigenous fishing in the south-western Cape. Chapter Nine gives an overview of the historical fishing at the Cape, the use of outposts near Langebaan Lagoon and Muizenberg in False Bay by the Dutch to supply the Cape settlement with provisions. In Chapter Ten the relevant evidence from each of the chapters is summarised and the conclusions for the three areas are presented.
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    Holocene evolution of the Anichab Pan on the south-west coast of Namibia.
    (Wiley, 2007) Compton, John S
    Coastal sediment-filled depressions (pans) are one of the few areas that contain Quaternary records of sea-level and palaeoenvironmental change along the western margin of southern Africa. Anichab is a 128 km2 salt-encrusted pan on the hyper-arid southern coast of Namibia with an emergent, well-preserved and in-place mid-Holocene mollusc assemblage. The molluscs are typical of subtidal sands on the sheltered side of offshore islands but include several warm-water species no longer found living along this coast. The Holocene evolution of the pan was largely influenced by changes in sea level and supply of sand along the coast. Calibrated radiocarbon ages of mollusc shells indicate a maximum Holocene sea level of ca 2 m above mean sea level (msl) from 7Æ0 to 6Æ3 ka and a return to near present-day sea level by 5Æ3 ka. The pan surface is 2 m below msl and has been emergent since 4Æ9 ka from the build up of sandy beaches and coastal dunes. A thin (1–4 cm) halite crust occurs over much of the pan surface but a layer of halite-cemented sand up to 40 cm thick is restricted to the central pan. Gypsum occurs near the subsurface brine interface and is limited by calcium to the edges of the pan. Nodules of calcite-cemented sand are forming in brackish, relatively high alkalinity subsurface waters in the southeast corner of the pan and nodules of aragonite-cemented sand are forming in brines 1 m below the central pan surface. Although modern dolomite has been reported from coastal lagoons of Brazil and Australia, carbonate cements are a minor feature of Anichab Pan and dolomite was restricted to a single reworked nodule most likely of Late Pleistocene age. Therefore, Anichab Pan does not appear to be a modern analogue to extensive, mixed-water dolomite cements found in Upper Pleistocene sediment-filled depressions on the Namibian shelf
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    Holocene vegetation history and environmental change in the forest-grassland mosaic of the Central Highlands of Madagascar
    (2022) Razafimanantsoa, Andriantsilavo Hery Isandratana; Gillson, Lindsey; Bond, William John
    The origin and classification of open and mosaic ecosystems, particularly in the tropics and subtropics, have led to controversy worldwide. This has affected biodiversity conservation and, in some cases, promoted the establishment of afforestation projects based on the assumption that open and mosaic ecosystems are degraded forests. Although this initiative can have benefits in terms of carbon storage and climate mitigation if carefully planned and managed, it can also cause biodiversity loss and degradation when afforestation takes place in areas that were previously open ecosystems, or where unsuitable species are used. Madagascar, a world biodiversity hotspot, is one of the countries targeted for the implementation of afforestation projects. The Central Highlands of Madagascar, dominated by grassland matrix with forest patches, is the main region targeted. The nature and origin of the landscape are hotly debated, however, and it is not clear whether these open ecosystems are ancient or anthropogenically derived. Understanding of landscape history is therefore required to identify and conserve ancient open ecosystems, and to distinguish them from areas that have been deforested by people. This research aims to reconstruct the vegetation history and environmental change in the Central Highlands of Madagascar during the Holocene using palaeoecological methods, in order to inform appropriate conservation and management plans. We provide new records of vegetation, hydrological change, fire and herbivory activities by using a multiproxy approach, which includes fossil pollen, stable carbon isotopes, diatoms, charcoal and coprophilous spores, that allows for a comprehensive investigation into the history and drivers of vegetation change. Sediment cores were collected from two sites, Tampoketsa-Ankazobe wetland and Lake Dangovavy, located in the eastern and western slopes of the highlands, respectively. Results indicated that the surrounding area of both sites was composed of mosaic ecosystems, comprising of forest patches of variable extent in a matrix of open grassland and ericoid shrubland vegetation, at least from the Early and Mid-Holocene to ca. 1000 cal years BP, driven mainly by climate variability and fire occurrence. In Tampoketsa-Ankazobe wetland (eastern slopes), the vegetation was characterised by a mosaic of ericoid shrubland and mid-elevation forest taxa, between ca. 11 200 and 8300 cal years BP, under warm/wet period and low fire occurrence. The vegetation in the area changed to a mosaic of ericoid shrubland with more dominance of high-elevation forest from ca. 8300 to 1000 cal years BP under a drier climate and consistent low fire occurrence. The abundance of shrubs and trees during those two periods were confirmed by the dominance of C3 plants as reflected by the stable carbon isotopes results, and coincided with low herbivory activities in the TampoketsaAnkazobe site from ca. 11 200 to 1000 cal years BP. In parallel, the pollen record from Lake Dangovavy (western slopes), between ca. 6200 and 5400 cal years BP, suggests a mosaic ecosystem, dominated by more C3 montane grass, ericoid shrubland and high elevation forest patches promoted by cool/dry climate with low fire occurrence and herbivory activities. Between ca. 5400 and 4200 cal years BP, vegetation in the area was dominated by a mosaic of ericoid shrubland and mid-elevation forest under a wetter period, moderate fire occurrence, and herbivory activities. This mosaic was controlled by climate, fire refugia and herbivory feedbacks. The vegetation changed into a forest-savanna mosaic with an abundance of grassland and pioneer/fire-resistant trees between ca. 4200 and 3000 cal years BP. The period was characterised by an initial increase of local fire followed by a regional drought event. This suggests that a threshold might have been reached, with a resulting shift in vegetation composition. Between ca. 3000 and 1000 cal years BP, reoccurrence of ericoid shrubland with woodland savanna taxa was recorded in the area. The vegetation was conditioned by variation of climate from wet (until ca. 2000 cal years BP) to dry period (ca. 2000–⁠1000 cal years BP) with moderate fire occurrence and herbivory activities. In addition, stable carbon isotope results show that between ca. 6200 to 1000 cal years BP, the site was characterised by C3 plants. During the last ca.1000 cal years BP, pollen records from both sites in the Central Highlands of Madagascar showed a shift to a more open landscape dominated by grassland. Trees and shrubland in the highlands experienced a massive decrease and this correlated with an abundance of C4 plants associated with reduced diversity. The shift of vegetation during this period was likely a result of a centennial severe drought period at ca. 950 cal years BP, as recorded in the literature and confirmed by the peak in aerophilous taxa in our diatom record. The drought was followed by a dramatic increase of fire occurrence and herbivory activities in the region, as recorded in the charcoal and spore records from both sites, indicating human activities at ca. 700 and 500 cal years BP for Lake Dangovavy and Tampoketsa-Ankazobe wetland, respectively. Though the vegetation at both sites in Central Highlands of Madagascar was very dynamic until ca. 1000 cal years BP, complex interactions between climate and fire allowed the forest and ericoid elements to persist, consistent with a heterogeneous mosaic landscape. This changed from 1000 years ago with the occurrence of a regional severe drought event followed by an increase in human activities leading to an increase of grass, a decline in forest and ericoid elements. Our findings suggest that although, the eastern and western slopes in Madagascar might have different vegetation histories over time as a response to the complex climatic-fire drivers at least until ca. 1000 cal years BP, they both: a) Contained ancient open ecosystems such as grasslands and/or ericoid shrubland, and a mosaic landscape which should be considered typical of the highland region. b) Experienced a loss of forest, woodland and mosaic elements, a trend that is consistent with the anthropogenic conversion of some forests to grasslands since ca. 1000 cal years BP. Such findings have implications in terms of conservation, fire management and afforestation projects in the Central Highlands, and provide additional knowledge that contributes to the understanding of its ecological processes and history prior to human arrival on the island. Indeed: 1) Ancient grasslands and ericoid shrubland need to be identified and conserved because of their antiquity and unique biodiversity. To date, there has been some focus on ancient grasslands, but the presence of ancient heathlands has not been discussed. 2) It is important to distinguish ancient from derived grasslands and to target the latter for reforestation, using species that are typical of the remaining forest patches. 3) Fire management should be conducted at a local scale and should incorporate the landscape fire history, considering, for example, the differences between two slopes in the Central Highlands.
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    Long bone cross-sectional geometric properties of Later Stone Age foragers and herder–foragers
    (2014) Cameron, Michelle E; Pfeiffer, Susan
    Diaphyseal cross-sectional geometry can be used to infer activity patterns in archaeological populations. We examined the cross-sectional geometric (CSG) properties of adult Later Stone Age (LSA) herder-forager long bones from the inland lower Orange River Valley of South Africa (n=5 m, 13 f). We then compared their CSG properties to LSA forager adults from the coastal fynbos (n=23 m, 14 f) and forest (n=17 m, 19 f) regions, building on a previous report (Stock and Pfeiffer, 2004). The periosteal mould method was used to quantify total subperiosteal area, torsional strength, bilateral asymmetry and diaphyseal circularity (Imax/Imin) at the mid-distal (35%) location of upper arms (humeri) and the mid-shaft (50%) location of upper legs (femora). Maximum humerus and femur lengths were similar among the three samples, suggesting that adult stature was similar in all three regions. When compared to the previous study, CSG property values obtained using the periosteal mould method correlated well, and there were no significant differences between data collected using the different methods. No statistically significant differences were found among the humerus or femur CSG properties from the different regions. This finding suggests that all individuals undertook similar volitional habitual activities in regard to their upper limbs, and also had similar degrees of terrestrial mobility. These results indicate relative behavioural homogeneity among LSA foragers and herder foragers from South Africa. The small degree of regional variation apparent among the three samples may reflect local ecology and the subsistence demands affecting populations in these different regions.
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    The mid-Holocene sea-level highstand at Bogenfels Pan on the southwest coast of Namibia
    (Elsevier, 2006) Compton, John S
    The radiocarbon ages of mollusc shells from the Bogenfels Pan on the hyper arid southern coast of Namibia provide constraints on the Holocene evolution of sea level and, in particular, the mid-Holocene highstand. The Bogenfels Pan was flooded to depths of 3 m above mean sea level (amsl) to form a large subtidal lagoon from 7300 to 6500 calibrated radiocarbon years before present (cal yr BP). The mollusc assemblage of the wave sheltered lagoon includes Nassarius plicatellus, Lutraria lutraria, and the bivalves Solen capensis and Gastrana matadoa, both of which no longer live along the wave-dominated southern Namibian coast. The radiocarbon ages of mollusc shell from a gravely beach deposit exposed in a diamond exploration trench indicate that sea level fell to near or 1 m below its present-day position between 6500 and 4900 cal yr BP. The rapid emergence of the pan between 6500 and 4900 cal yr BP exceeds that predicted by glacio-isostatic models and may indicate a 3-m eustatic lowering of sea level. The beach deposits at Bogenfels indicate that sea level rose to 1 m amsl between 4800 and 4600 cal yr BP and then fell briefly between 4600 and 4200 cal yr BP before returning to 1 m amsl. Since 4200 cal yr BP sea level has remained within one meter of the present-day level and the beach at Bogenfels has prograded seaward from the delayed arrival of sand by longshore drift from the Orange River. A 6200 cal yr BP coastal midden and a 600 cal yr BP midden 1.7 km from the coast indicate sporadic human utilization of the area. The results of this study are consistent with previous studies and help to refine the Holocene sea-level record for southern Africa.
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    The mid-Holocene sea-level highstand at Bogenfels Pan on the southwest coast of Namibia
    (Elsevier, 2006) Compton, J
    The radiocarbon ages of mollusc shells from the Bogenfels Pan on the hyper arid southern coast of Namibia provide constraints on the Holocene evolution of sea level and, in particular, the mid-Holocene highstand. The Bogenfels Pan was flooded to depths of 3 m above mean sea level (amsl) to form a large subtidal lagoon from 7300 to 6500 calibrated radiocarbon years before present (cal yr BP). The mollusc assemblage of the wave sheltered lagoon includes Nassarius plicatellus, Lutraria lutraria, and the bivalves Solen capensis and Gastrana matadoa, both of which no longer live along the wave-dominated southern Namibian coast. The radiocarbon ages of mollusc shell from a gravely beach deposit exposed in a diamond exploration trench indicate that sea level fell to near or 1 m below its present-day position between 6500 and 4900 cal yr BP. The rapid emergence of the pan between 6500 and 4900 cal yr BP exceeds that predicted by glacio-isostatic models and may indicate a 3-m eustatic lowering of sea level. The beach deposits at Bogenfels indicate that sea level rose to 1 m amsl between 4800 and 4600 cal yr BP and then fell briefly between 4600 and 4200 cal yr BP before returning to 1 m amsl. Since 4200 cal yr BP sea level has remained within one meter of the present-day level and the beach at Bogenfels has prograded seaward from the delayed arrival of sand by longshore drift from the Orange River. A 6200 cal yr BP coastal midden and a 600 cal yr BP midden 1.7 km from the coast indicate sporadic human utilization of the area. The results of this study are consistent with previous studies and help to refine the Holocene sea-level record for southern Africa.
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    Postural behaviour of Later Stone Age people in South Africa
    (South African Archaeological Society, 2004) Dewar, Genevieve; Pfeiffer, Susan
    Prehistoric human skeletal remains from Later Stone Age archaeological sites, South Africa, were examined for evidence of habitual use of a squatting posture during life. Bony facets that are believed to be associated with habitual squatting were identified on the tali and the proximal tibial condyles of adult bones. The sample (n=98 adults) was found to exhibit the highest frequency yet reported of the lateral F squatting facet on the talus. A high frequency of medial traits is also reported, including both the medial squatting facet and medial condylar rounding, which have been rare in other populations. There is no statistically significant difference in the expression of traits by broadly defined time periods, age at death, or sex. Individuals from the same region show similar patterns of squatting facets, but there is considerable interregional variation among the Western Cape, the Southern Cape, and the Eastern Cape. The pattern of traits related to squatting postures is consistent with lean body builds, in which there is little soft tissue resistance to deep joint flexion. Most adults appear to have regularly assumed the squatting posture, but there may have been regional differences in stance preferences.