ORCID Profile
0000-0002-8634-014X
Current Organisation
University of Glasgow
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Publisher: Public Library of Science (PLoS)
Date: 02-11-2017
Publisher: Cambridge University Press (CUP)
Date: 24-10-2016
DOI: 10.1017/RDC.2016.86
Abstract: The Last Glacial–Interglacial Transition (LGIT 15,000–11,000 cal BP) was characterized by complex spatiotemporal patterns of climate change, with numerous studies requiring accurate chronological control to decipher leads from lags in global paleoclimatic, paleoenvironmental, and archaeological records. However, close scrutiny of the few available tree-ring chronologies and radiocarbon-dated sequences composing the IntCal13 14 C calibration curve indicates significant weakness in 14 C calibration across key periods of the LGIT. Here, we present a decadally resolved atmospheric 14 C record derived from New Zealand kauri spanning the Lateglacial from ~13,100–11,365 cal BP. Two floating kauri 14 C time series, curve-matched to IntCal13, serve as a 14 C backbone through the Younger Dryas. The floating Northern Hemisphere (NH) 14 C data sets derived from the YD-B and Central European Lateglacial Master tree-ring series are matched against the new kauri data, forming a robust NH 14 C time series to ~14,200 cal BP. Our results show that IntCal13 is questionable from ~12,200–11,900 cal BP and the ~10,400 BP 14 C plateau is approximately 5 decades too short. The new kauri record and repositioned NH pine 14 C series offer a refinement of the international 14 C calibration curves IntCal13 and SHCal13, providing increased confidence in the correlation of global paleorecords.
Publisher: Elsevier BV
Date: 12-2016
Publisher: Springer Science and Business Media LLC
Date: 19-05-2016
DOI: 10.1038/SREP25902
Abstract: The Greenland Stadial 1 (GS-1 ~12.9 to 11.65 kyr cal BP) was a period of North Atlantic cooling, thought to have been initiated by North America fresh water runoff that caused a sustained reduction of North Atlantic Meridional Overturning Circulation (AMOC), resulting in an antiphase temperature response between the hemispheres (the ‘bipolar seesaw’). Here we exploit sub-fossil New Zealand kauri trees to report the first securely dated, decadally-resolved atmospheric radiocarbon ( 14 C) record spanning GS-1. By precisely aligning Southern and Northern Hemisphere tree-ring 14 C records with marine 14 C sequences we document two relatively short periods of AMOC collapse during the stadial, at ~12,920-12,640 cal BP and 12,050-11,900 cal BP. In addition, our data show that the interhemispheric atmospheric 14 C offset was close to zero prior to GS-1, before reaching ‘near-modern’ values at ~12,660 cal BP, consistent with synchronous recovery of overturning in both hemispheres and increased Southern Ocean ventilation. Hence, sustained North Atlantic cooling across GS-1 was not driven by a prolonged AMOC reduction but probably due to an equatorward migration of the Polar Front, reducing the advection of southwesterly air masses to high latitudes. Our findings suggest opposing hemispheric temperature trends were driven by atmospheric teleconnections, rather than AMOC changes.
Publisher: Elsevier BV
Date: 07-2016
DOI: 10.1016/J.CUB.2016.05.046
Abstract: Stone tools reveal worldwide innovations in human behaviour over the past three million years [1]. However, the only archaeological report of pre-modern non-human animal tool use comes from three Western chimpanzee (Pan troglodytes verus) sites in Côte d'Ivoire, aged between 4.3 and 1.3 thousand years ago (kya) [2]. This anthropocentrism limits our comparative insight into the emergence and development of technology, weakening our evolutionary models [3]. Here, we apply archaeological techniques to a distinctive stone tool assemblage created by a non-human animal in the New World, the Brazilian bearded capuchin monkey (Sapajus libidinosus). Wild capuchins at Serra da Capivara National Park (SCNP) use stones to pound open defended food, including locally indigenous cashew nuts [4], and we demonstrate that this activity dates back at least 600 to 700 years. Capuchin stone hammers and anvils are therefore the oldest non-human tools known outside of Africa, opening up to scientific scrutiny questions on the origins and spread of tool use in New World monkeys, and the mechanisms - social, ecological and cognitive - that support primate technological evolution.
Publisher: Cambridge University Press (CUP)
Date: 2013
DOI: 10.2458/AZU_JS_RC.V55I2.16217
Abstract: Wc describe here the New Zealand kauri ( Agathis australis ) Younger Dryas (YD) research project, which aims to undertake Δ 14 C analysis of ∼140 decadal floating wood s les spanning the time interval ∼13.1–11.7 kyr cal BP. We report 14 C intercomparison measurements being undertaken by the carbon dating laboratories at University of Waikato (Wk), University of California at Irvine (UCI), and University of Oxford (OxA). The Wk, UCI, and OxA laboratories show very good agreement with an interlaboratory comparison of 12 successive decadal kauri s les (average offsets from consensus values of –7 to +4 14 C yr). A University of Waikato/University of Heidelberg (HD) intercomparison involving measurement of the YD-age Swiss larch tree Ollon505, shows a HD/Wk offset of ∼10–20 14 C yr (HD younger), and strong evidence that the positioning of the Ollon505 series is incorrect, with a recommendation that the 14 C analyses be removed from the IntCal calibration database.
Publisher: Copernicus GmbH
Date: 12-06-2019
Abstract: Abstract. The Tibetan Plateau is of peculiar societal relevance as it provides freshwater from the so-called “Water Tower of Asia” to a large portion of the Asian population. However, future climate change will affect the hydrological cycle in this area. To define parameters for future climate change scenarios it is necessary to improve the knowledge about thresholds, timing, pace and intensity of past climatic changes and associated environmental impacts. Sedimentary archives reaching far back in time and spanning several glacial–interglacial cycles such as Nam Co provide the unique possibility to extract such information. In order to explore the scientific opportunities that an ICDP drilling effort at Nam Co would provide, 40 scientists from 13 countries representing various scientific disciplines met in Beijing from 22 to 24 May 2018. Besides paleoclimatic investigations, opportunities for paleomagnetic, deep biosphere, tectonic and paleobiological studies were discussed. After having explored the technical and logistical challenges and the scientific opportunities all participants agreed on the great value and need to drill this extraordinary archive, which has a sediment thickness of more than 1 km, likely covering more than 1 Ma.
Publisher: Elsevier BV
Date: 12-2016
Publisher: Springer Science and Business Media LLC
Date: 24-06-2019
DOI: 10.1038/S41559-019-0904-4
Abstract: The human archaeological record changes over time. Finding such change in other animals requires similar evidence, namely, a long-term sequence of material culture. Here, we apply archaeological excavation, dating and analytical techniques to a wild capuchin monkey (Sapajus libidinosus) site in Serra da Capivara National Park, Brazil. We identify monkey stone tools between 2,400 and 3,000 years old and, on the basis of metric and damage patterns, demonstrate that capuchin food processing changed between ~2,400 and 300 years ago, and between ~100 years ago and the present day. We present the first ex le of long-term tool-use variation outside of the human lineage, and discuss possible mechanisms of extended behavioural change.
Publisher: Cambridge University Press (CUP)
Date: 2013
DOI: 10.2458/AZU_JS_RC.55.16947
Abstract: The IntCal09 and Marine09 radiocarbon calibration curves have been revised utilizing newly available and updated data sets from 14 C measurements on tree rings, plant macrofossils, speleothems, corals, and foraminifera. The calibration curves were derived from the data using the random walk model (RWM) used to generate IntCal09 and Marine09, which has been revised to account for additional uncertainties and error structures. The new curves were ratified at the 21st International Radiocarbon conference in July 2012 and are available as Supplemental Material at www.radiocarbon.org. The database can be accessed at intcal.qub.ac.uk/intcal13/.
Publisher: Springer Science and Business Media LLC
Date: 12-09-2017
DOI: 10.1038/S41467-017-00577-6
Abstract: Contrasting Greenland and Antarctic temperatures during the last glacial period (115,000 to 11,650 years ago) are thought to have been driven by imbalances in the rates of formation of North Atlantic and Antarctic Deep Water (the ‘bipolar seesaw’). Here we exploit a bidecadally resolved 14 C data set obtained from New Zealand kauri ( Agathis australis ) to undertake high-precision alignment of key climate data sets spanning iceberg-rafted debris event Heinrich 3 and Greenland Interstadial (GI) 5.1 in the North Atlantic (~30,400 to 28,400 years ago). We observe no ergence between the kauri and Atlantic marine sediment 14 C data sets, implying limited changes in deep water formation. However, a Southern Ocean (Atlantic-sector) iceberg rafted debris event appears to have occurred synchronously with GI-5.1 warming and decreased precipitation over the western equatorial Pacific and Atlantic. An ensemble of transient meltwater simulations shows that Antarctic-sourced salinity anomalies can generate climate changes that are propagated globally via an atmospheric Rossby wave train.
Publisher: Elsevier BV
Date: 06-2013
Publisher: Elsevier BV
Date: 04-2016
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Richard Staff.