skip to main content
Explore Scholarly Publications and Datasets in the NSF-PAR

  • NSF Public Access
  • Search Results
  • Accepted Manuscript: Coastal occupation and foraging during the last glacial maximum and early Holocene at Waterfall Bluff, eastern Pondoland, South Africa
Title: Coastal occupation and foraging during the last glacial maximum and early Holocene at Waterfall Bluff, eastern Pondoland, South Africa
Abstract Waterfall Bluff is a rock shelter in eastern Pondoland, South Africa, adjacent to a narrow continental shelf that limited coastline movements across glacial/interglacial cycles. The archaeological deposits are characterized by well-preserved stratigraphy, faunal, and botanical remains alongside abundant stone artifacts and other materials. A comprehensive dating protocol consisting of 5 optically stimulated luminescence ages and 51 accelerator mass spectrometry 14 C ages shows that the record of hunter-gatherer occupations at Waterfall Bluff persisted from the late Pleistocene to the Holocene, spanning the last glacial maximum and the transition from the Pleistocene to the Holocene. Here, we provide detailed descriptions about the sedimentary sequence, chronology, and characteristics of the archaeological deposits at Waterfall Bluff. Remains of marine mollusks and marine fish also show, for the first time, that coastal foraging was a component of some hunter-gatherer groups’ subsistence practices during glacial phases in the late Pleistocene. The presence of marine fish and shellfish further demonstrates that hunter-gatherers selectively targeted coastal resources from intertidal and estuarine habitats. Our results therefore underscore the idea that Pondoland's coastline remained a stable and predictable point on the landscape over the last glacial/interglacial transition being well positioned for hunter-gatherers to access resources from the nearby more » coastline, narrow continental shelf, and inland areas. « less
Authors:
; ; ; ; ; ; ; ; ; ;
Award ID(s):
1827326
Publication Date:
NSF-PAR ID:
10272928
Journal Name:
Quaternary Research
Volume:
97
Page Range or eLocation-ID:
1 to 41
ISSN:
0033-5894
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ( , Scientific prospectus)
    The Iberian margin is a well-known source of rapidly accumulating sediment that contains a high-fidelity record of millennial climate variability (MCV) for the late Pleistocene. The late Sir Nicholas (Nick) Shackleton demonstrated that piston cores from the region can be correlated precisely to polar ice cores in both hemispheres. Moreover, the narrow continental shelf off Portugal results in the rapid delivery of terrestrial material to the deep-sea environment, thereby permitting correlation of marine and ice core records to European terrestrial sequences. Few places exist in the world where such detailed marine-ice-terrestrial linkages are possible. The continuity, high sedimentation rates, and fidelity of climate signals preserved in Iberian margin sediments make this region a prime target for ocean drilling. During Integrated Ocean Drilling Program Expedition 339 (Mediterranean Outflow), one of the sites proposed here was drilled to a total depth of 155.9 meters below seafloor in multiple holes. At Site U1385 (the “Shackleton site”) a complete record of hemipelagic sedimentation was recovered for the last 1.45 My corresponding to Marine Isotope Stage 47 with sedimentation rates of 10–20 cm/ky. Preliminary results from Site U1385 demonstrate the great promise of the Iberian margin to yield long records of millennial-scale climate change andmore »land–sea comparisons. International Ocean Discovery Program (IODP) Expedition 397 will extend this remarkable sediment archive through the Pliocene and expand the depth range of available sites by drilling additional sequences in water depths from 1304 to 4686 meters below sea level (mbsl). This depth transect is designed to complement those sites drilled during Expedition 339 (560–1073 mbsl) where sediment was recovered at intermediate water depth under the influence of Mediterranean Outflow Water (MOW). Together, the sites recovered during Expeditions 339 and 397 will constitute a complete depth transect with which to study past variability of all the major subsurface water masses of the eastern North Atlantic. Because most of the mass, thermal inertia, and carbon in the ocean-atmosphere system is contained in the deep ocean, well-placed depth transects in each of the major ocean basins are needed to understand the underlying mechanisms of glacial–interglacial cycles and MCV. We have identified four primary sites (SHACK-4C, SHACK-10B, SHACK-11B, and SHACK-14A) at which multiple holes will be drilled to ensure complete recovery of the stratigraphic sections at each site, ranging in age from the latest Miocene to Holocene. Building on the success of Site U1385 and given the seminal importance of the Iberian margin for paleoclimatology and marine-ice-terrestrial correlations, the cores recovered during Expedition 397 will provide present and future generations of paleoceanographers with the raw material needed to reconstruct the North Atlantic climate at high temporal resolution for the entire Quaternary and Pliocene.« less
  2. ; ; ( , Proceedings of the International Ocean Discovery Program)
    The Amundsen Sea sector of Antarctica has long been considered the most vulnerable part of the West Antarctic Ice Sheet (WAIS) because of the great water depth at the grounding line, a subglacial bed seafloor deepening toward the interior of the continent, and the absence of substantial ice shelves. Glaciers in this configuration are thought to be susceptible to rapid or runaway retreat. Ice flowing into the Amundsen Sea Embayment is undergoing the most rapid changes of any sector of the Antarctic ice sheets outside the Antarctic Peninsula, including substantial grounding-line retreat over recent decades, as observed from satellite data. Recent models suggest that a threshold leading to the collapse of WAIS in this sector may have been already crossed and that much of the ice sheet could be lost even under relatively moderate greenhouse gas emission scenarios. Drill cores from the Amundsen Sea provide tests of several key questions about controls on ice sheet stability. The cores offer a direct offshore record of glacial history in a sector that is exclusively influenced by ice draining the WAIS, which allows clear comparisons between the WAIS history and low-latitude climate records. Today, relatively warm (modified) Circumpolar Deep Water (CDW) is impingingmore »onto the Amundsen Sea shelf and causing melting under ice shelves and at the grounding line of the WAIS in most places. Reconstructions of past CDW intrusions can assess the ties between warm water upwelling and large-scale changes in past grounding-line positions. Carrying out these reconstructions offshore from the drainage basin that currently has the most substantial negative mass balance of ice anywhere in Antarctica is thus of prime interest to future predictions. The scientific objectives for this expedition are built on hypotheses about WAIS dynamics and related paleoenvironmental and paleoclimatic conditions. The main objectives are: 1. To test the hypothesis that WAIS collapses occurred during the Neogene and Quaternary and, if so, when and under which environmental conditions; 2. To obtain ice-proximal records of ice sheet dynamics in the Amundsen Sea that correlate with global records of ice-volume changes and proxy records for atmospheric and ocean temperatures; 3. To study the stability of a marine-based WAIS margin and how warm deepwater incursions control its position on the shelf; 4. To find evidence for the earliest major grounded WAIS advances onto the middle and outer shelf; 5. To test the hypothesis that the first major WAIS growth was related to the uplift of the Marie Byrd Land dome. International Ocean Discovery Program (IODP) Expedition 379 completed two very successful drill sites on the continental rise of the Amundsen Sea. Site U1532 is located on a large sediment drift, now called the Resolution Drift, and it penetrated to 794 m with 90% recovery. We collected almost-continuous cores from recent age through the Pleistocene and Pliocene and into the upper Miocene. At Site U1533, we drilled 383 m (70% recovery) into the more condensed sequence at the lower flank of the same sediment drift. The cores of both sites contain unique records that will enable study of the cyclicity of ice sheet advance and retreat processes as well as ocean-bottom water circulation and water mass changes. In particular, Site U1532 revealed a sequence of Pliocene sediments with an excellent paleomagnetic record for high-resolution climate change studies of the previously sparsely sampled Pacific sector of the West Antarctic margin. Despite the drilling success at these sites, the overall expedition experienced three unexpected difficulties that affected many of the scientific objectives: 1. The extensive sea ice on the continental shelf prevented us from drilling any of the proposed shelf sites. 2. The drill sites on the continental rise were in the path of numerous icebergs of various sizes that frequently forced us to pause drilling or leave the hole entirely as they approached the ship. The overall downtime caused by approaching icebergs was 50% of our time spent on site. 3. A medical evacuation cut the expedition short by 1 week. Recovery of core on the continental rise at Sites U1532 and U1533 cannot be used to indicate the extent of grounded ice on the shelf or, thus, of its retreat directly. However, the sediments contained in these cores offer a range of clues about past WAIS extent and retreat. At Sites U1532 and U1533, coarse-grained sediments interpreted to be ice-rafted debris (IRD) were identified throughout all recovered time periods. A dominant feature of the cores is recorded by lithofacies cyclicity, which is interpreted to represent relatively warmer periods variably characterized by sediments with higher microfossil abundance, greater bioturbation, and higher IRD concentrations alternating with colder periods characterized by dominantly gray laminated terrigenous muds. Initial comparison of these cycles to published late Quaternary records from the region suggests that the units interpreted to be records of warmer time intervals in the core tie to global interglacial periods and the units interpreted to be deposits of colder periods tie to global glacial periods. Cores from the two drill sites recovered sediments of dominantly terrigenous origin intercalated or mixed with pelagic or hemipelagic deposits. In particular, Site U1533, which is located near a deep-sea channel originating from the continental slope, contains graded silts, sands, and gravels transported downslope from the shelf to the rise. The channel is likely the pathway of these sediments transported by turbidity currents and other gravitational downslope processes. The association of lithologic facies at both sites predominantly reflects the interplay of downslope and contouritic sediment supply with occasional input of more pelagic sediment. Despite the lack of cores from the shelf, our records from the continental rise reveal the timing of glacial advances across the shelf and thus the existence of a continent-wide ice sheet in West Antarctica during longer time periods since at least the late Miocene. Cores from both sites contain abundant coarse-grained sediments and clasts of plutonic origin transported either by downslope processes or by ice rafting. If detailed provenance studies confirm our preliminary assessment that the origin of these samples is from the plutonic bedrock of Marie Byrd Land, their thermochronological record will potentially reveal timing and rates of denudation and erosion linked to crustal uplift. The chronostratigraphy of both sites enables the generation of a seismic sequence stratigraphy for the entire Amundsen Sea continental rise, spanning the area offshore from the Amundsen Sea Embayment westward along the Marie Byrd Land margin to the easternmost Ross Sea through a connecting network of seismic lines.« less
  3. ; ; ( , Preliminary report)
    The Amundsen Sea sector of Antarctica has long been considered the most vulnerable part of the West Antarctic Ice Sheet (WAIS) because of the great water depth at the grounding line and the absence of substantial ice shelves. Glaciers in this configuration are thought to be susceptible to rapid or runaway retreat. Ice flowing into the Amundsen Sea Embayment is undergoing the most rapid changes of any sector of the Antarctic Ice Sheet outside the Antarctic Peninsula, including changes caused by substantial grounding-line retreat over recent decades, as observed from satellite data. Recent models suggest that a threshold leading to the collapse of WAIS in this sector may have been already crossed and that much of the ice sheet could be lost even under relatively moderate greenhouse gas emission scenarios. Drill cores from the Amundsen Sea provide tests of several key questions about controls on ice sheet stability. The cores offer a direct record of glacial history offshore from a drainage basin that receives ice exclusively from the WAIS, which allows clear comparisons between the WAIS history and low-latitude climate records. Today, warm Circumpolar Deep Water (CDW) is impinging onto the Amundsen Sea shelf and causing melting of the undersidemore »of the WAIS in most places. Reconstructions of past CDW intrusions can assess the ties between warm water upwelling and large-scale changes in past grounding-line positions. Carrying out these reconstructions offshore from the drainage basin that currently has the most substantial negative mass balance of ice anywhere in Antarctica is thus of prime interest to future predictions. The scientific objectives for this expedition are built on hypotheses about WAIS dynamics and related paleoenvironmental and paleoclimatic conditions. The main objectives are 1. To test the hypothesis that WAIS collapses occurred during the Neogene and Quaternary and, if so, when and under which environmental conditions; 2. To obtain ice-proximal records of ice sheet dynamics in the Amundsen Sea that correlate with global records of ice-volume changes and proxy records for atmospheric and ocean temperatures; 3. To study the stability of a marine-based WAIS margin and how warm deep-water incursions control its position on the shelf; 4. To find evidence for earliest major grounded WAIS advances onto the middle and outer shelf; 5. To test the hypothesis that the first major WAIS growth was related to the uplift of the Marie Byrd Land dome. International Ocean Discovery Program (IODP) Expedition 379 completed two very successful drill sites on the continental rise of the Amundsen Sea. Site U1532 is located on a large sediment drift, now called Resolution Drift, and penetrated to 794 m with 90% recovery. We collected almost-continuous cores from the Pleistocene through the Pliocene and into the late Miocene. At Site U1533, we drilled 383 m (70% recovery) into the more condensed sequence at the lower flank of the same sediment drift. The cores of both sites contain unique records that will enable study of the cyclicity of ice sheet advance and retreat processes as well as bottom-water circulation and water mass changes. In particular, Site U1532 revealed a sequence of Pliocene sediments with an excellent paleomagnetic record for high-resolution climate change studies of the previously sparsely sampled Pacific sector of the West Antarctic margin. Despite the drilling success at these sites, the overall expedition experienced three unexpected difficulties that affected many of the scientific objectives: 1. The extensive sea ice on the continental shelf prevented us from drilling any of the proposed shelf sites. 2. The drill sites on the continental rise were in the path of numerous icebergs of various sizes that frequently forced us to pause drilling or leave the hole entirely as they approached the ship. The overall downtime caused by approaching icebergs was 50% of our time spent on site. 3. An unfortunate injury to a member of the ship's crew cut the expedition short by one week. Recovery of core on the continental rise at Sites U1532 and U1533 cannot be used to precisely indicate the position of ice or retreat of the ice sheet on the shelf. However, these sediments contained in the cores offer a range of clues about past WAIS extent and retreat. At Sites U1532 and U1533, coarse-grained sediments interpreted to be ice-rafted debris (IRD) were identified throughout all recovered time periods. A dominant feature of the cores is recorded by lithofacies cyclicity, which is interpreted to represent relatively warmer periods variably characterized by higher microfossil abundance, greater bioturbation, and higher counts of IRD alternating with colder periods characterized by dominantly gray laminated terrigenous muds. Initial comparison of these cycles to published records from the region suggests that the units interpreted as records of warmer time intervals in the core tie to interglacial periods and the units interpreted as deposits of colder periods tie to glacial periods. The cores from the two drill sites recovered sediments of purely terrigenous origin intercalated or mixed with pelagic or hemipelagic deposits. In particular, Site U1533, which is located near a deep-sea channel originating from the continental slope, contains graded sands and gravel transported downslope from the shelf to the abyssal plain. The channel is likely the path of such sediments transported downslope by turbidity currents or other sediment-gravity flows. The association of lithologic facies at both sites predominantly reflects the interplay of downslope and contouritic sediment supply with occasional input of more pelagic sediment. Despite the lack of cores from the shelf, our records from the continental rise reveal the timing of glacial advances across the shelf and thus the existence of a continent-wide ice sheet in West Antarctica at least during longer time periods since the late Miocene. Cores from both sites contain abundant coarse-grained sediments and clasts of plutonic origin transported either by downslope processes or by ice rafting. If detailed provenance studies confirm our preliminary assessment that the origin of these samples is from the plutonic bedrock of Marie Byrd Land, their thermochronological record will potentially reveal timing and rates of denudation and erosion linked to crustal uplift. The chronostratigraphy of both sites enables the generation of a seismic sequence stratigraphy not only for the Amundsen Sea rise but also for the western Amundsen Sea along the Marie Byrd Land margin through a connecting network of seismic lines.« less
  4. ; ; ; ; ; ; ; ; ( , The Cryosphere)
    Abstract. Chronologies of glacier deposits in the Transantarctic Mountains provide important constraints on grounding-line retreat during the last deglaciation in the Ross Sea. However, between Beardmore Glacier and Ross Island – a distance of some 600 km – the existing chronologies are generally sparse and far from the modern grounding line, leaving the past dynamics of this vast region largely unconstrained. We present exposure ages of glacial deposits at three locations alongside the Darwin–Hatherton Glacier System – including within 10 km of the modern grounding line – that record several hundred meters of Late Pleistocene to Early Holocene thickening relative to present. As the ice sheet grounding line in the Ross Sea retreated, Hatherton Glacier thinned steadily from about 9 until about 3 ka. Our data are equivocal about the maximum thickness and Mid-Holocene to Early Holocene history at the mouth of Darwin Glacier, allowing for two conflicting deglaciation scenarios: (1) ∼500 m of thinning from 9 to 3 ka, similar to Hatherton Glacier, or (2) ∼950 m of thinning, with a rapid pulse of ∼600 m thinning at around 5 ka. We test these two scenarios using a 1.5-dimensional flowband model, forced by ice thickness changes at the mouth of Darwin Glacier and evaluated by fit tomore »the chronology of deposits at Hatherton Glacier. The constraints from Hatherton Glacier are consistent with the interpretation that the mouth of Darwin Glacier thinned steadily by ∼500 m from 9 to 3 ka. Rapid pulses of thinning at the mouth of Darwin Glacier are ruled out by the data at Hatherton Glacier. This contrasts with some of the available records from the mouths of other outlet glaciers in the Transantarctic Mountains, many of which thinned by hundreds of meters over roughly a 1000-year period in the Early Holocene. The deglaciation histories of Darwin and Hatherton glaciers are best matched by a steady decrease in catchment area through the Holocene, suggesting that Byrd and/or Mulock glaciers may have captured roughly half of the catchment area of Darwin and Hatherton glaciers during the last deglaciation. An ensemble of three-dimensional ice sheet model simulations suggest that Darwin and Hatherton glaciers are strongly buttressed by convergent flow with ice from neighboring Byrd and Mulock glaciers, and by lateral drag past Minna Bluff, which could have led to a pattern of retreat distinct from other glaciers throughout the Transantarctic Mountains.« less
  5. ; ; ; ; ; ; ; ( , American Journal of Biological Anthropology)
    Historically, hunter-gatherers living east and west of the Andean foothills of southern South America (Fuego-Patagonia) practiced different subsistence strategies. To the east, the wide open and relatively dry pampas presented a climate ideal for Terrestrial hunter-gatherers who depended on terrestrial animals (e.g., Lama guanicoe). In contrast, Marine hunter-gatherers who lived on islands in the western archipelago, a colder and wetter environment, mainly subsisted on marine resources (e.g., seals and shellfish). Archaeological evidence dates Terrestrial hunter-gatherers’ presence in Fuego-Patagonia to at least ~10,500 BP, whereas Marine hunter-gatherers’ presence dates to ~6,500 BP and is associated with highly specialized tools that have only been observed in the archaeological record after this time. Genetic analyses of some ancient Fuegian-Patagonians have supported the hypothesis that Marine hunter-gatherers migrated into the region after Terrestrial hunter-gatherers, around 6,500 BP (7,500 calBP), while analyses of other individuals suggest that Marine hunter-gatherers descended from the earlier Terrestrial hunter-gatherer groups. Here, we test these hypotheses by analyzing newly collected genome-wide data from n=46 ancient Chilean Fuegian-Patagonian individuals belonging to Marine, Terrestrial, and Mixed-economy archaeological sites dating to 6,895–304 calBP. We explored basic population structure among these hunter-gatherer groups using PCA and ADMIXTURE. We calculated π, pairwise-FST, and f-statistics, andmore »developed demographic simulations to further examine genetic relationships among the groups. The results of this study shed light on local demographic patterns of ancient southern South American groups, which in turn provides more insight into broader population histories of South America. This study was funded by FONDECYT (Chile), National Geographic Society, National Science Foundation, and Wenner-Gren Foundation. C. M. Balentine is supported by an NSF Graduate Research Fellowship.« less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email