21 research outputs found
Quantitative dating of pleistocene deposits of the Kyrenia range, Northern Cyprus : implications for timing, rates of uplift and driving mechanisms
R.N.P. acknowledges the NERC CASE scholarship at the University of Edinburgh. Additional field and laboratory work was aided by the DARIUS Programme to A.H.F.R. and T.C.K. We are grateful for the additional financial support provided by the John Dixon Memorial Fund.The Kyrenia Range underwent tectonically driven uplift during the Pliocene to Pleistocene in response to the interaction of various tectonic processes. To understand the tectonic processes driving the uplift and how this is related to uplift of other areas of the Eastern Mediterranean, uranium-series disequilibrium and optically stimulated luminescence dating were applied to marine and non-marine terrace deposits exposed on the northern flank of the range. Palaeomagnetism and strontium isotope dating were used in conjunction to date the final stages of the marine environment adjacent to the Kyrenia Range prior to major surface uplift. Uplift rates range from >1.2 mm a−1, inferred during the Early Pleistocene, to <0.2 mm a−1during the Late Pleistocene. The new data show that the Kyrenia Range was uplifted contemporaneously with the Troodos Massif in southern Cyprus. The uplift of the Kyrenia Range appears to have been significantly faster than that affecting other comparable regions in the easternmost Mediterranean during the Pleistocene (e.g. Lebanon coast; southern Anatolian plateau). The driving mechanism for the uplift of both the Kyrenia Range and the Troodos Massif is inferred to be the collision of the Eratosthenes Seamount with the Cyprus trench to the south of Cyprus.Publisher PDFPeer reviewe
Evolution of the continental lithosphere: evidence from volcanics and xenoliths in southern Africa
The geology of southern Africa offers a rare opportunity to study the evolution of a segment of continental lithosphere because its rocks range in age from 3.6 Ga to recent, and over the last 200 Ma both the upper mantle and the crust have been sampled by Karoo and Tertiary volcanism and as xenoliths in kimberlite pipes
Quantitation of protactinium, <sup>231</sup>Pa in abyssal carbonate
Quantitation of protactinium, 231Pa in abyssal carbonates at ~10–12 g g–1 levels, presents certain challenges because it is the only isotope of this element that is present in the natural environment and its half-life of 32 800 y is too long for useful measurement using alpha-particle or gamma-ray spectroscopy. However, because it is an isotope in the 235U decay chain, closely linked to the 238U decay chain, quantitation can be achieved relative to a carbonate standard in secular radioactive equilibrium. The 238U, 235U, 234U, 230Th and 232Th isotopes in the carbonate standard are determined with a mixed 236U-229Th spike using isotope dilution protocols and a Multi-Collector Inductively Coupled Plasma Mass Spectrometer
Marks of sanctity? Discovery of rock art on the Gower Peninsula, South Wales
Abstract Britain is regarded by some as an Upper Palaeolithic cultural backwater, but this part of northwestern Europe also encountered the ravages of the Devensian with the southern limit of the ice margin extending a few kilometers north of the limestone caves on the Gower Peninsula, South Wales. Following sudden climatic warming, groups of hunter/fisher/gatherers started to utilize this sometimes hostile landscape, seasonally occupying many of the caves that are cut and shaped into the limestone outcropping that frequents the Gower Peninsula. At this time an extensive landmass would have replaced much of the present Bristol Channel (Jacobi 1980). It is indeed a rare occurrence for Pleistocene rock art to be discovered within the British Isles, with only one authenticated discovery made in 2003 at Church Hole Cave at Creswell Crags on the Derbyshire/Nottinghamshire border (Bahn and Pettitt 2009). It is not too fanciful to suggest that in order to secure a successful hunt or merely to revere a spiritual being that metaphysically occupied the rear section of the cave, artists were engraving within its hidden recesses. This short article announces and contextually describes a recent discovery of probable Pleistocene rock art on the Gower Peninsula, South Wales. Reprinted by permission of the publisher
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Determination of thorium and uranium isotope ratios in low-concentration geological materials using a fixed multi-collector-ICP-MS
Techniques used for the measurement of thorium and uranium isotope ratios in low-concentration (<0.1 ppm) geological materials on a Nu Instruments® MC-ICP-MS are described. Using an Aridus® micro-concentric, desolvating nebuliser sample introduction system, the beam current in a Faraday collector is typically 1.0 nA ppm–1232Th (total system efficiency = 0.3%). The abundance sensitivity is less than 100 counts s–1 at 1 mass unit below a large peak with an intensity of 1 × 109 counts s–1, or <0.1 ppm. The Faraday–ion counting gain is stable over a day and the method can provide 230Th/232Th ratio measurements on ng quantities of total dissolved Th to a precision that is better than 1%(95% confidence level). This is comparable to results obtained by thermal ionisation mass spectrometry on samples that are typically 10 to 100 times larger. Results for our internal laboratory standards are presented together with our results for standards used in other laboratories to facilitate inter-laboratory comparison
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A discovery of possible upper palaeolithic parietal art in Cathole Cave, Gower Peninsula, South Wales
In September 2010 an engraving was discovered in Cathole Cave on the Gower peninsula in South Wales which has been interpreted as a possible representation of a cervid. Uranium series dating of calcite which overlays part of the engraving has been dated to approx. 12,500 BP suggesting a possible Upper Palaeolithic date for the figure