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

IF 1.2 4区地球科学 Q2 GEOLOGY

South African Journal of Geology Pub Date : 2021-07-23 DOI:10.25131/SAJG.124.0031

J. Knight

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引用次数: 1

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.

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非洲南部晚第四纪崩坡积层的地层学和古环境解释

整个南部非洲的斜坡和低地沉积物系统主要由崩积层与互层古土壤和硬地硬壳组成。这些沉积物分别对应于第四纪晚期的地表不稳定和稳定阶段。本研究根据斜坡系统动力学的理论思想，包括沉积物供应和容纳空间，研究了非洲南部特定地点海洋同位素阶段（MIS）6至1（至今约191 ka）斜坡沉积物记录的地层学和环境解释。基于此分析，确定了MIS 6至1期间的地表不稳定和稳定阶段。地表条件的空间和时间模式并不是气候强迫的简单反映，而是反映了斜坡系统对气候的反应，以及在集水区尺度沉积物系统中运行的地质、土壤和生态因素的作用。考虑这些系统动力学可以更好地理解斜坡沉积物地层的有用性和局限性。

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来源期刊

South African Journal of Geology 地学-地质学

CiteScore

3.60

自引率

5.60%

发文量

审稿时长

>12 weeks

期刊介绍： The South African Journal of Geology publishes scientific papers, notes, stratigraphic descriptions and discussions in the broadly defined fields of geoscience that are related directly or indirectly to the geology of Africa. Contributions relevant to former supercontinental entities such as Gondwana and Rodinia are also welcome as are topical studies on any geoscience-related discipline. Review papers are welcome as long as they represent original, new syntheses. Special issues are also encouraged but terms for these must be negotiated with the Editors.