A proposed chronostratigraphic framework for the late Quaternary of southern Africa

2021 ◽  
Author(s):  
J. Knight ◽  
J.M. Fitchett
Keyword(s):  
Southern Africa ◽  
Environmental Variability ◽  
Late Quaternary ◽  
Evolutionary Development ◽  
Testable Hypothesis ◽  
Data Types ◽  
Spatial And Temporal Patterns ◽  
Quaternary Period ◽  
Climate And Environmental Change ◽  
Time Periods

Abstract The principles of chronostratigraphy can inform the process of correlation between different palaeoclimate records, enabling the coherence of spatial and temporal patterns of past climates and environments to be identified based on the physical, chemical, biological and isotopic properties of individual depositional units. This study presents a chronostratigraphic framework for the late Quaternary of southern Africa, based on the integration of palaeoclimatic and palaeoenvironmental proxy data from key records across the country from the start of Marine Isotope Stage 6 (~191 ka BP) to present. The methodology adopted in this study involves, first, wiggle-matching between sufficiently long and continuous records from different regions across southern Africa, informed by radiometric age controls from individual records. Based on interpretive limitations of these records, we then integrate different geomorphic and archaeological data types in proposing successive chronostratigraphic time periods that collectively extend through the late Quaternary of southern Africa. These time periods correspond to phases in which, within them, a certain set of (relative) stable climates or environments existed in different regions of southern Africa, as recorded in different ways in different proxy records. The boundaries between successive time periods are identified where there is evidence for a significant change in the workings of the climate or environmental system as reflected in the preserved proxy record found in a certain locality. These chronostratigraphic units are interpreted as reflecting the impacts of external forcing that is of regional extent, synchronous, and are not merely an outcome of local environmental variability. These chronostratigraphic phases identified for the late Quaternary period also correspond to distinctive technological and cultural phases in the southern African archaeological record, demonstrating links between coeval climate and environmental change and phases of human evolutionary development. This chronostratigraphic approach provides both a correlative framework for understanding the varied late Quaternary records of southern Africa, and a testable hypothesis for considering the synchroneity or otherwise of different records and thus their associated forcing factors.

Stratigraphy and palaeoenvironmental interpretation of late Quaternary colluvial slope deposits in southern Africa

2021 ◽  
Author(s):  
J. Knight
Keyword(s):  
Southern Africa ◽  
Land Surface ◽  
Late Quaternary ◽  
Ecological Factors ◽  
Surface Instability ◽  
Sediment Supply ◽  
Spatial And Temporal Patterns ◽  
Catchment Scale ◽  
Accommodation Space ◽  
Slope Sediment

Abstract Slope and lowland sediment systems throughout southern Africa are dominated by the presence of colluvium with interbedded palaeosols and hardground duricrusts. These sediments correspond to phases of land surface instability and stability, respectively, during the late Quaternary. This study examines the stratigraphy and environmental interpretation of slope sediment records from specific sites in southern Africa for the period of marine isotope stages (MIS) 6 to 1 (~191 ka to present), informed by theoretical ideas of the dynamics of slope systems including sediment supply and accommodation space. Based on this analysis, phases of land surface instability and stability for the period MIS 6 to 1 are identified. The spatial and temporal patterns of land surface conditions are not a simple reflection of climate forcing, but rather reflect the workings of slope systems in response to climate in addition to the role of geologic, edaphic and ecological factors that operate within catchment-scale sediment systems. Considering these systems dynamics can yield a better understanding of the usefulness and limitations of slope sediment stratigraphies.

Carnivore Size and Quaternary Climatic Change in Southern Africa

1986 ◽  
Vol 26 (1) ◽  
pp. 153-170 ◽  
Author(s):  
Richard G. Klein
Keyword(s):  
South Africa ◽  
Southern Africa ◽  
Late Quaternary ◽  
Geochemical Data ◽  
Mathematical Relationship ◽  
Carnivore Species ◽  
Quantitative Estimates ◽  
The Relationship ◽  
Problematic Aspect ◽  
Cool Conditions

The relationship between carnassial length and latitude south is analyzed for 17 African carnivore species to determine if individuals tend to be larger in cooler climates, as predicted by Bergmann's Rule. With modern data in support, middle and late Quaternary temperatures might then be inferred from mean carnassial length in fossil samples, such as those from Equus Cave, Elandsfontein, Sea Harvest. Duinefontein, and Swartklip in the Cape Province of South Africa. One problematic aspect of the study is the use of carnassial length and latitude as necessary but imperfect substitutes for body size and temperature, respectively. For some species, another difficulty is the relatively small number of available modern specimens, combined with their uneven latitudinal spread. Still, in 14 of the species, carnassial length does tend to increase with latitude south, while mean carnassial length in the same species tends to be greater in those fossil samples which accumulated under relatively cool conditions, as inferred from sedimentologic, palynological, or geochemical data. Given larger modern samples from a wide variety of latitudes, refinement of the mathematical relationship between carnassial length and latitude in various species may even permit quantitative estimates of past temperatures in southern Africa.

scholarly journals Late Quaternary Landscape Dynamics at the La Spezia Gulf (NW Italy): A Multi-Proxy Approach Reveals Environmental Variability within a Rocky Embayment

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 427
Author(s):  
Veronica Rossi ◽  
Alessandro Amorosi ◽  
Marco Marchesini ◽  
Silvia Marvelli ◽  
Andrea Cocchianella ◽  
...  
Keyword(s):  
Sea Level ◽  
Environmental Variability ◽  
Late Quaternary ◽  
Landscape Dynamics ◽  
Last Interglacial ◽  
Core Depth ◽  
Coastal Bay ◽  
Nw Italy ◽  
Global Sea Level ◽  
Geomorphological Features

The Gulf of La Spezia (GLS) in Northwest Italy is a rocky embayment with low fluvial influence facing the Mediterranean Sea. Past landscape dynamics were investigated through a multi-proxy, facies-based analysis down to a core depth of 30 m. The integration of quantitative ostracod, foraminifera, and pollen analyses, supported by radiocarbon ages, proved to be a powerful tool to unravel the late Quaternary palaeoenvironmental evolution and its forcing factors. The complex interplay between relative sea-level (RSL), climatic changes, and geomorphological features of the embayment drove four main evolution phases. A barrier–lagoon system developed in response to the rising RSL of the Late Pleistocene (likely the Last Interglacial). The establishment of glacial conditions then promoted the development of an alluvial environment, with generalised erosion of the underlying succession and subsequent accumulation of fluvial strata. The Holocene transgression (dated ca. 9000 cal year BP) caused GLS inundation and the formation of a low-confined lagoon basin, which rapidly turned into a coastal bay from ca. 8000 cal year BP onwards. This latter environmental change occurred in response to the last Holocene stage of global sea-level acceleration, which submerged a morphological relief currently forming a drowned barrier-island complex in the embayment.

Late Quaternary deep marine sediment records off southern Africa

2021 ◽  
Author(s):  
H.C. Cawthra ◽  
E.W. Bergh ◽  
E.A. Wiles ◽  
J.S. Compton
Keyword(s):  
Southern Africa ◽  
Late Quaternary ◽  
Strongly Correlated ◽  
Sea Level Fluctuations ◽  
Proxy Records ◽  
Terrestrial Environments ◽  
Bottom Waters ◽  
Resolution Mapping ◽  
And Shifts ◽  
Glacial Periods

Abstract High-resolution mapping, sampling and analysis of upper Quaternary southern African continental margin sediments recovered from beyond the Last Glacial Maximum shoreline (>130 m water depth) have expanded our understanding of how marine and terrestrial records are linked over glacial-interglacial climatic cycles. This paper synthesises data currently available from the deep seafloor around southern Africa and, specifically, core sites that demonstrate terrestrial sedimentological connectivity. Several proxies and case studies reveal the evolution of depositional systems, palaeoceanography and palaeoclimate over the last 191 kyr. Hydroacoustic mapping and investigations of submarine canyons have been carried out primarily on the eastern and southwestern margins, while palaeoceanographic productivity and microfossil assemblages have been applied most extensively on the western marine and southern Agulhas Bank. Studies on the western margin indicate that enhanced productivity, less oxygenated bottom waters and reduced marine faunal diversity in the transition to glacial periods, while glacial terminations are associated with reduced productivity and more oxygenated bottom waters. These changes, linked to palaeoceanography and late Quaternary sea-level fluctuations, influence the sedimentary record and sedimentation rates. On the eastern margin, sediment fluxes applied as proxies for rainfall offshore of the Great Kei, Umzimvubu, Limpopo and Zambezi rivers indicate that the southern African climate responds to changes in orbitally-modulated insolation and in particular, to the ~23 kyr precessional cycle, where the proxy records keep pace with this and then diverge at ~80 to 70 kyr. Since the penultimate glacial (Marine Isotope Stage/MIS 6), more humid conditions observed in southern Africa, as the Northern Hemisphere entered phases of rapid cooling, were potentially driven by a combination of warming in the Agulhas Current and shifts of the subtropical anticyclones. Broadly, the sedimentary records reviewed suggest fluctuations in climate and oceanographic circulation that are strongly correlated with the global benthic δ18O record, suggesting sensitivity to high-latitude forcing, and a strong influence of late Quaternary glacial-interglacial cycles despite these marine sites being far-removed from terrestrial environments.

scholarly journals Late glacial (17,060–13,400 cal yr BP) sedimentary and paleoenvironmental evolution of the Sekhokong Range (Drakensberg), southern Africa

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0246821
Author(s):  
Malin E. Kylander ◽  
Mikaela Holm ◽  
Jennifer Fitchett ◽  
Stefan Grab ◽  
Antonio Martinez Cortizas ◽  
...  
Keyword(s):  
Southern Africa ◽  
Late Quaternary ◽  
Thermal Conditions ◽  
Late Glacial ◽  
Cold Season ◽  
Winter Precipitation ◽  
High Temporal Resolution ◽  
Local Evidence ◽  
Paleoenvironmental Evolution ◽  
Reflectance Ftir

Southern Africa sits at the junction of tropical and temperate systems, leading to the formation of seasonal precipitation zones. Understanding late Quaternary paleoclimatic change in this vulnerable region is hampered by a lack of available, reliably-dated records. Here we present a sequence from a well-stratified sedimentary infill occupying a lower slope basin which covers 17,060 to 13,400 cal yr BP with the aim to reconstruct paleoclimatic variability in the high Drakensberg during the Late Glacial. We use a combination of pollen, total organic carbon and nitrogen, δ13C, Fourier transform infrared spectroscopy attenuated total reflectance (FTIR-ATR) spectral and elemental data on contiguous samples with high temporal resolution (10 to 80 years per sample). Our data support a relatively humid environment with considerable cold season precipitation during what might have been the final stage of niche-glaciation on the adjoining southern aspects around 17,000 cal yr BP. Then, after an initial warmer and drier period starting ~15,600 cal yr BP, we identify a return to colder and drier conditions with more winter precipitation starting ~14,380 cal yr BP, which represents the first local evidence for the Antarctic Cold Reversal (ACR) in this region. On decadal to centennial timescales, the Late Glacial period was one marked by considerable climatic fluctuation and bi-directional environmental change, which has not been identified in previous studies for this region. Our study shows complex changes in both moisture and thermal conditions providing a more nuanced picture of the Late Glacial for the high Drakensburg.

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