Browsing by Author "Marean, Curtis W."
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- A high-resolution chronology for the archaeological deposits at Pinnacle Point 5–6, Western Cape Province, South AfricaPublication . Jacobs, Zenobia; Karkanas, Panagiotis; Fahey, B. Patrick; Fisher, Erich Christopher; Marean, Curtis W.Pinnacle Point Site 5-6 (PP5-6) is a key archaeological and paleoenvironmental site located on the edge of the Palaeo-Agulhas Plain along the southern Cape coast of South Africa. Construction of high-resolution chronologies for archaeological sites beyond the range of radiocarbon dating is challenging. Geochronological methods such as optical dating are hampered by the availability of applicable materials that are directly associated with the events of interest. Optical dating relies on assumptions made about time-dependent changes and is made up of a series of measurements each with its own random and systematic uncertainties that together make up the age estimates. In this study, we explicitly took on the challenge to systematically produce a high-resolution chronology for PP5-6 made up of 197 individual age estimates of which 169 were input into a Bayesian age model. PP5-6 is ideal because of its fine-scale stratigraphy and use of modern excavation techniques and detailed recording of stratigraphy and plotted finds. Excavations and dating took place concurrently over almost two decades to inform the dating strategy, contextualise sample choice and data analysis, and to bring the scales of analysis of different proxies closer together. Here we present the optical dating process, including sensitivity tests of our instruments, data analysis procedures and modelling approach. We then construct a final timeline for comparisons with other proxy data and interpretation of the sedimentary sequence and occupation of PP5-6 over an interval of similar to 60,000 years from similar to 110,000 to similar to 50,000 years ago. We show how closely linked sediment deposition is to changes in global climate and sea-level, identify a few Pleistocene and Holocene erosional events that modified the site post-depositionally and place a variety of interconnected causes and effects coincident with different types of occupation on this timeline. This approach opens up opportunities to reduce the resolution of chronologies closer to the human timescales required to improve our understanding of changes through time and to make more direct comparisons between other sites and proxies that contain similarly highly resolved archives of human occupation and change.
- Lithic technological responses to Late Pleistocene glacial cycling at Pinnacle Point Site 5-6, South AfricaPublication . Wilkins, Jayne; Brown, Kyle S.; Oestmo, Simen; Pereira, Telmo; Ranhorn, Kathryn L.; Schoville, Benjamin J.; Marean, Curtis W.There are multiple hypotheses for human responses to glacial cycling in the Late Pleistocene, including changes in population size, interconnectedness, and mobility. Lithic technological analysis informs us of human responses to environmental change because lithic assemblage characteristics are a reflection of raw material transport, reduction, and discard behaviors that depend on hunter-gatherer social and economic decisions. Pinnacle Point Site 5-6 (PP5-6), Western Cape, South Africa is an ideal locality for examining the influence of glacial cycling on early modern human behaviors because it preserves a long sequence spanning marine isotope stages (MIS) 5, 4, and 3 and is associated with robust records of paleoenvironmental change. The analysis presented here addresses the question, what, if any, lithic assemblage traits at PP5-6 represent changing behavioral responses to the MIS 5-4-3 interglacial-glacial cycle? It statistically evaluates changes in 93 traits with no a priori assumptions about which traits may significantly associate with MIS. In contrast to other studies that claim that there is little relationship between broad-scale patterns of climate change and lithic technology, we identified the following characteristics that are associated with MIS 4: increased use of quartz, increased evidence for outcrop sources of quartzite and silcrete, increased evidence for earlier stages of reduction in silcrete, evidence for increased flaking efficiency in all raw material types, and changes in tool types and function for silcrete. Based on these results, we suggest that foragers responded to MIS 4 glacial environmental conditions at PP5-6 with increased population or group sizes, 'place provisioning', longer and/or more intense site occupations, and decreased residential mobility. Several other traits, including silcrete frequency, do not exhibit an association with MIS. Backed pieces, once they appear in the PP5-6 record during MIS 4, persist through MIS 3. Changing paleoenvironments explain some, but not all temporal technological variability at PP5-6.
- Mapping magnetism: geophysical modelling of stratigraphic features by using in situ magnetic susceptibility measurements at Pinnacle Point 5‐6 North, South AfricaPublication . Dinckal, Ada; Fisher, Erich; Herries, Andy I. R.; Marean, Curtis W.This study utilizes geostatistical modelling of magnetic susceptibility (MS) for geophysical prospection of archaeological stratigraphy at the Middle Stone Age rock shelter site of Pinnacle Point 5-6 North. These models are overlaid onto high-resolution photography of the stratigraphic sequence to study the lateral and vertical changes within the magnetic signature of the archaeological sequence and correlate these changes to micromorphological interpretations previously made at the site. In situ analysis is reinforced by laboratory magnetic mineralogical analysis utilizing MS; frequency-dependent susceptibility (chi(FD)); isothermal remanent magnetization; and anhysteric remanent magnetization to understand the composition of the magnetic minerals creating the in situ signature. This study shows that there is consistent variation in the magnetic signatures of the sequence that can be mapped with in situ MS; there is a correlation with laboratory analysis of magnetic mineralogy, which provides insight into changes in human behaviour; and our models correlate well with micromorphological interpretations of the site.
- A new MIS 5 to MIS 2 speleothem record from Sandkraal Cave on the South African Cape south coastPublication . Braun, Kerstin; Bar-Matthews, Miryam; Ayalon, Avner; Matthews, Alan; Zilberman, Tami; Zolotova, Natalya; Cowling, Richard M.; Karkanas, Panagiotis; Cawthra, Hayley C.; Fisher, Erich; Edwards, R. Lawrence; Li, Xianglei; Marean, Curtis W.We present new stable oxygen and carbon isotope composite records (delta O-18, delta C-13) of speleothems from Sandkraal Cave 1 (SK1) on the South African south coast for the time interval between 104 and 18 ka (with a hiatus between 48 and 41 ka). Statistical comparisons using kernel-based correlation analyses and semblance analyses based on continuous wavelet transforms inform the relationships of the new speleothem records to other proxies and their changes through time. Between 105 and similar to 70 ka, changes of speleothem delta O-18 values at SK1 are likely related to rainfall seasonality. Variations of delta C-13 values are associated with changes of vegetation density, prior carbonate precipitation (PCP), CO2 degassing in the cave, and possibly variations of the abundance of C-3 and C-4 grasses in the vegetation. The relationships of delta O-18 with other proxies shift between similar to 70 and 48 ka (Marine Isotope Stages 4-3) so that both stable isotope records now reflect CO2 degassing, evaporation, and PCP. Similar relationships also continue after the hiatus for the deposition phase between 42 and 18 ka. Our findings support modeling results suggesting drier conditions in the study area when the Southern Hemisphere westerlies are shifted north and the paleo-Agulhas Plain is exposed.
- A worked bone assemblage from 120,000–90,000 year old deposits at Contrebandiers Cave, Atlantic Coast, MoroccoPublication . Hallett, Emily Y.; Marean, Curtis W.; Steele, Teresa E.; Álvarez-Fernández, Esteban; Jacobs, Zenobia; Cerasoni, Jacopo Niccolò; Aldeias, Vera; Scerri, Eleanor M.L.; Olszewski, Deborah I.; El Hajraoui, Mohamed Abdeljalil; Dibble, Harold L.The emergence of Homo sapiens in Pleistocene Africa is associated with a pro found reconfiguration of technology. Symbolic expression and personal orna mentation, new tool forms, and regional technological traditions are widely recognized as the earliest indicators of complex culture and cognition in humans. Here we describe a bone tool tradition from Contrebandiers Cave on the Atlantic coast of Morocco, dated between 120,000–90,000 years ago. The bone tools were produced for different activities, including likely leather and fur working, and were found in association with carnivore remains that were possibly skinned for fur. A cetacean tooth tip bears what is likely a combination of anthropogenic and non-anthropogenic modification and shows the use of a marine mammal tooth by early humans. The evidence from Contrebandiers Cave demonstrates that the pan-African emergence of complex culture included the use of multiple and diverse materials for specialized tool manufacture.