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Large freshwater lakes formed in North America and Europe during deglaciation following the Last Glacial Maximum. Rapid drainage of these lakes into the Oceans resulted in abrupt perturbations in climate, including the Younger Dryas and... more
Large freshwater lakes formed in North America and Europe during deglaciation following the Last Glacial Maximum. Rapid drainage of these lakes into the Oceans resulted in abrupt perturbations in climate, including the Younger Dryas and 8.2 kyr cooling events. In the mid-latitudes of the Southern Hemisphere major glacial lakes also formed and drained during deglaciation but little is known about the magnitude, organization and timing of these drainage events and their effect on regional climate. We use 16 new single-grain optically stimulated luminescence (OSL) dates to define three stages of rapid glacial lake drainage in the Lago General Carrera/Lago Buenos Aires and Lago Cohrane/Pueyrredón basins of Patagonia and provide the first assessment of the effects of lake drainage on the Pacific Ocean. Lake drainage occurred between 13 and 8 kyr ago and was initially gradual eastward into the Atlantic, then subsequently reorganized westward into the Pacific as new drainage routes opened ...
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The INQUA Dunes Atlas project has developed a global digital database of chronological information for periods of inland or continental sand dune accumulation and stabilization. The database comprises information on the site location... more
The INQUA Dunes Atlas project has developed a global digital database of chronological information for periods of inland or continental sand dune accumulation and stabilization. The database comprises information on the site location (including coordinates), dune type, and stratigraphic context, pertinent analytical information (e.g. luminescence procedures), and literature citations to the original data source. This paper discusses the background to the project, the concept and structure of the chronologic database that forms its core, and gives some examples of the scope of the database and ways in which it can contribute to greater understanding of the spatial and temporal variability in dune development.
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Abstract In comparison to Southwest Asia and the Indian subcontinent, the relationship between Holocene river dynamics, climate change and floodwater farming in Central Asia is significantly under researched. To address this, a... more
Abstract In comparison to Southwest Asia and the Indian subcontinent, the relationship between Holocene river dynamics, climate change and floodwater farming in Central Asia is significantly under researched. To address this, a multi-disciplinary research project was begun in 2011 centred on the Talgar catchment, a south-bank tributary of the Ili River, southeast Kazakhstan. Building on archaeological excavations and surveys conducted over the past 20 years, we have undertaken investigations of Holocene human adaptations to changing hydromorphic regimes in the Tien Shan piedmont region, Central Asia. Fluvial geochronologies have been reconstructed over the last 20,000 years using Optically Stimulated Luminescence and 14C dating, and are compared with human settlement histories from the Eneolithic to the medieval period. Phases of Late Pleistocene and Holocene river aggradation at c. 17,400–6420, 4130–2880 and 910–500 cal. BC and between the mid-18th and early 20th centuries were coeval with cooler and wetter neoglacial episodes. Entrenchment and floodplain soil development (c. 2880–2490 cal. BC and cal. AD 1300–1640) coincided with warmer and drier conditions. Prior to the modern period, floodwater farming in the Talgar River reached its height in the late Iron Age (400 cal. BC – cal. AD 1) with more than 70 settlement sites and 700 burial mounds. This period of agricultural expansion corresponds to a phase of reduced flooding, river stability and glacier retreat in the Tien Shan Mountains. Late Iron age agriculturists appear to have been opportunistic by exploiting a phase of moderate flows within an alluvial fan environment, which contained a series of partially entrenched distributary channels that could be easily ‘engineered’ to facilitate floodwater farming. Holocene climate change was therefore not a proximate cause for the development and demise of this relatively short-lived (c. 200 years) period of Iron Age farming. River dynamics in the Tien Shan piedmont are, however, strongly coupled with regional hydroclimatic fluctuations, and they have likely acted locally as both ‘push’ and ‘pull’ factors for riparian agriculturists.
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Research Interests: Archaeology, Geology, Human Evolution, Coastal Dunes, Arid environments, and 15 moreDesertification, Arabian Gulf, OSL dating, Luminescence Dating, Palaeoclimate, Monsoon, Middle Palaeolithic, Late Pleistocene to Early Holocene, Monsoon climatology, Chronology, Dunes, Arabia, Coastal Sand Dunes, Indian monsoon, and Arabian Peninsula In Antiquity
Research Interests: Archaeology, Earth Sciences, Geology, Geomorphology, Climate Change, and 15 moreTransition, Patagonia, Late Pleistocene, Text, Holocene, Climate history, History and archaeology, Late Holocene, Climatic Factor, South America, Southern Hemisphere, Early Holocene, Quaternary Science Reviews, Valley, and Record
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This paper presents data on the extent of the North Patagonian Icefield during the Late Pleistocene–Holocene transition using cosmogenic nuclide exposure age and optically stimulated luminescence dating. We describe geomorphological and... more
This paper presents data on the extent of the North Patagonian Icefield during the Late Pleistocene–Holocene transition using cosmogenic nuclide exposure age and optically stimulated luminescence dating. We describe geomorphological and geochronological evidence for glacier extent in one of the major valleys surrounding the North Patagonian Icefield, the Rio Bayo valley. Geomorphological mapping provides evidence for the existence of two types of former ice masses in this area: (i) a large outlet glacier of the North Patagonian Icefield, which occupied the main Rio Bayo valley, and (ii) a number of small glaciers that developed in cirques on the slopes of the mountains surrounding the valley. Cosmogenic nuclide exposure-age dating of two erratic boulders on the floor of the Rio Bayo valley indicate that the outlet glacier of the icefield withdrew from the Rio Bayo valley after 10,900 ± 1000 yr (the mean of two boulders dated to 11,400 ± 900 yr and 10,500 ± 800 yr). Single-grain opti...
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The collapse of the Bronze Age Harappan, one of the earliest urban civilizations, remains an enigma. Urbanism flourished in the western region of the Indo-Gangetic Plain for approximately 600 y, but since approximately 3,900 y ago, the... more
The collapse of the Bronze Age Harappan, one of the earliest urban civilizations, remains an enigma. Urbanism flourished in the western region of the Indo-Gangetic Plain for approximately 600 y, but since approximately 3,900 y ago, the total settled area and settlement sizes declined, many sites were abandoned, and a significant shift in site numbers and density towards the east is recorded. We report morphologic and chronologic evidence indicating that fluvial landscapes in Harappan territory became remarkably stable during the late Holocene as aridification intensified in the region after approximately 5,000 BP. Upstream on the alluvial plain, the large Himalayan rivers in Punjab stopped incising, while downstream, sedimentation slowed on the distinctive mega-fluvial ridge, which the Indus built in Sindh. This fluvial quiescence suggests a gradual decrease in flood intensity that probably stimulated intensive agriculture initially and encouraged urbanization around 4,500 BP. Howev...
Research Interests: Ancient History, Geography, Archaeology, Climate Change, Geoarchaeology, and 15 moreFluvial Processes, GeoArcheology, Climate, Fluvial Geomorphology, Central Asia, Civilization, Dynamics, Alluvial fans, Asia, Floods, Droughts, Archaeology of Societal Collapse, Fluvial, Geologic Sediments, and Flood Myth
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Research Interests: Earth Sciences, Geology, Geochemistry, Sedimentology, Climate Change, and 13 moreRivers, South Asian Archaeology, Pleistocene, Indus Valley Civilization, Quaternary Sedimentology and Geomorphology, Sediment Provenance, Es, Harappan Archaeology, Himalayan geology, Detrital Zircon Geochronology, Zircon, Indus River Culture, and Indus River
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The Cuicuilco pyramid was one of the first true urban centres in the Basin of Mexico. Its construction started a few centuries BC, during the Late Preclassic period. The pyramid is partially covered by a basaltic lava flow produced by the... more
The Cuicuilco pyramid was one of the first true urban centres in the Basin of Mexico. Its construction started a few centuries BC, during the Late Preclassic period. The pyramid is partially covered by a basaltic lava flow produced by the Xitle monogenetic volcano. New stratigraphic work around the pyramid and the volcano together with new radiocarbon dates indicate that the pyramid and nearby settlements were abandoned as a direct consequence of the volcanic activity of Xitle. The new dates, obtained from material which clearly is contemporaneous with the volcanic activity, suggest that the eruption took place around 1670 years BP, some 300 years later than previously thought.
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The Maputaland area of northeastern South Africa is characterized by extensive dunefields which developed during polyphase reworking of regional aeolian cover sand from the Mid-Pleistocene to the Holocene. Extended parabolic dunes, many... more
The Maputaland area of northeastern South Africa is characterized by extensive dunefields which developed during polyphase reworking of regional aeolian cover sand from the Mid-Pleistocene to the Holocene. Extended parabolic dunes, many preserved only as wind-rift trailing limbs, as well as areas of sinuous crested dunes, hummocky dune systems and the high, composite, accretionary coastal barrier dune cordon are the dominant dune forms. There are few natural sections exposing the stratigraphic succession and unequivocal relative age relationships between dune systems are uncommon. A ground penetrating radar (GPR) survey of dunes and representative aeolian sand stratigraphic units was undertaken in order to investigate the internal structure of the different dune forms and identify stratigraphic relationships between buried sedimentary units. The GPR profiles revealed that the trailing limbs of almost all the parabolic dunes that were surveyed comprise stacked sand units, separated b...
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... ten years has been the adoption of new meas-urement procedures that have permitted analysis of samples using smaller amo-unts of ... but this may have been caused by a phenomenon termed 'anomalous... more
... ten years has been the adoption of new meas-urement procedures that have permitted analysis of samples using smaller amo-unts of ... but this may have been caused by a phenomenon termed 'anomalous fading' which can affect measurements of feldspars (eg Spooner 1994). ...
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The Indus River basin has evolved significantly during the Holocene and may have affected the Harappan Civilization which is believed to have collapsed around 2000 BC. We aim to understand the links between drainage evolution, the... more
The Indus River basin has evolved significantly during the Holocene and may have affected the Harappan Civilization which is believed to have collapsed around 2000 BC. We aim to understand the links between drainage evolution, the intensity of the South Asian Monsoon and the development of this early human society. Sediment was sampled from modern rivers, pits and shallow boreholes in the alluvial plains of the Indus and the inactive Ghaggar-Hakra tributary. A suite of techniques are used to resolve sediment source ...
Ground penetrating radar (GPR) profiles across a complex linear dune in the Namib Sand Sea have been used to image sets of cross-stratification and their bounding surfaces. A combination of radar facies analysis and radar stratigraphy has... more
Ground penetrating radar (GPR) profiles across a complex linear dune in the Namib Sand Sea have been used to image sets of cross-stratification and their bounding surfaces. A combination of radar facies analysis and radar stratigraphy has been used to interpret the ...
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Located at the crossroads between Africa and Eurasia, Arabia occupies a pivotal position for human migration and dispersal during the Late Pleistocene. Deducing the timing of humid and arid phases is critical to understanding when the... more
Located at the crossroads between Africa and Eurasia, Arabia occupies a pivotal position for human migration and dispersal during the Late Pleistocene. Deducing the timing of humid and arid phases is critical to understanding when the Rub' al-Khali desert acted as a barrier to human movement and settlement. Recent geological mapping in the northern part of the Rub' al-Khali has enabled the Qua- ternary history of the region to be put into a regional stratigraphical framework. In addition to the active dunes, two significant palaeodune sequences have been identified. Dating of key sections has enabled a chronology of dune accretion and stabilisation to be determined. In addition, previously published optically stimulated luminescence (OSL) dates have been put in their proper stratigraphical context, from which a record of Late Pleistocene dune activity can be constructed. The results indicate the record of dune activity in the northern Rub' al-Khali is preservation limited and is synchronous with humid events driven by the incursion of the Indian Ocean monsoon.
Research Interests: Palaeoclimatology, Human Evolution, Palaeolithic Archaeology, Coastal Dunes, Arid environments, and 18 moreDesertification, Arabian Gulf, OSL dating, Luminescence Dating, Palaeoclimate, Pleistocene, Monsoon, Middle Palaeolithic, Late Pleistocene to Early Holocene, United Arab Emirates, Monsoon climatology, Chronology, Arabian/Persian Gulf Studies, Arabian/Persian Gulf Archaeology, Arabian Peninsula in Antiquity, Coastal Sand Dunes, Sand dunes, and Indian monsoon
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In the Eurasian Upper Paleolithic after about 35,000 years ago, abstract or depictional images provide evidence for cognitive abilities considered integral to modern human behavior. Here we report on two abstract representations engraved... more
In the Eurasian Upper Paleolithic after about 35,000 years ago, abstract or depictional images provide evidence for cognitive abilities considered integral to modern human behavior. Here we report on two abstract representations engraved on pieces of red ochre recovered from the Middle Stone Age layers at Blombos Cave in South Africa. A mean date of 77,000 years was obtained for the layers containing the engraved ochres by thermoluminescence dating of burnt lithics, and the stratigraphic integrity was confirmed by an optically stimulated luminescence age of 70,000 years on an overlying dune. These engravings support the emergence of modern human behavior in Africa at least 35,000 years before the start of the Upper Paleolithic.
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Research Interests: Evolutionary Biology, Archaeology, Paleontology, Anthropology, Human Evolution, and 17 moreRadiocarbon, Optical Dating, TIME, South Africa, Measurement, Dating, Middle Stone Age, Sediment, Laboratory, SAND, Radiation Dose, Optics and Photonics, Time, Sand Dune Ecology, Silicon Dioxide, Geologic Sediments, and Infrared Rays
Optical ages for 14 sediment samples collected from the post-Howiesons Poort, late Middle Stone Age (MSA) and final MSA deposits at Sibudu, KwaZulu-Natal, South Africa were reported in a companion paper (Jacobs, Z., Wintle, AG, Duller,... more
Optical ages for 14 sediment samples collected from the post-Howiesons Poort, late Middle Stone Age (MSA) and final MSA deposits at Sibudu, KwaZulu-Natal, South Africa were reported in a companion paper (Jacobs, Z., Wintle, AG, Duller, GAT, Roberts, RG, Wadley, L. New ages ...
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Avulsions are most characteristic of aggrading fluvial systems, but along the Klip River, subhumid eastern South Africa, abandonment and re-establishment of meander belts occurs under conditions of negligible vertical aggradation. Channel... more
Avulsions are most characteristic of aggrading fluvial systems, but along the Klip River, subhumid eastern South Africa, abandonment and re-establishment of meander belts occurs under conditions of negligible vertical aggradation. Channel banks are fully alluvial, but the bed is ...