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Elemental and isotopic fingerprinting of Chinese archaeological ceramics /Li, Baoping. January 2006 (has links) (PDF)
Thesis (Ph.D.) - University of Queensland, 2006. / Includes bibliography.
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Sm-Nd isotopic disequilibrium between minerals in Merenskycyclic units of the Bushveld Complex, South AfricaMkaza, Masizole 28 January 2009 (has links)
M.Sc. / Please refer to full text to view abstract
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The petrography, mineral chemistry and isotope geochemistry of a mantle xenolith suite from the Letlhakane DK 1 and DK 2 kimberlite pipes, BotswanaStiefenhofer, Johann January 1994 (has links)
No description available.
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Development of 6 MV tandem acclerator mass spectrometry facility and its applicationsSekonya, Kamela Godwin January 2017 (has links)
A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy, School of Physics. Johannesburg, 2017. / Accelerator Mass Spectrometry (AMS) is an ultra-sensitive isotopic analysis technique
that allows for the determination of isotopic ratios of rare long-lived radionuclides such as
radiocarbon. AMS has become an important tool in many scientific disciplines, due to its
sensitivity of detecting isotopic ratios at the level of 10-15 by making use of nuclear physics
techniques and methods.
The objective of the present work was to design and implement a new AMS system at
iThemba LABS, the first of its kind on the African continent. The system is described in detail
along with the relevant ion optics simulations using TRACE-3D. Beam optics calculations
were performed for carbon isotopes, using the TRACE-3D code, in order to optimize the design
of the new spectrometer and assess its overall performance.
The AMS technique was applied in two unique South African research projects in
relation to archaeology and environmental air pollution studies. The AMS technique, combined
with the Proton-Induced X-Ray Emission (PIXE) technique, was also applied in an
environmental study with respect to the contribution of contemporary and fossil carbon in air
pollution in the Lephalale District, close to both the newly built Medupi coal-fired power
station (~5 GW, the largest ever build in South Africa), and the existing Matimba coal-fired
power station.
The discrimination of contemporary carbon and fossil carbon is accomplished by using
the AMS technique in measurements of the 14C/C ratios of aerosol particulate matter. The
absence of 14C in fossil carbon material and the known 14C/C ratio levels in contemporary
carbon material allows us to distinguish between contemporary carbon and fossil carbon and
decipher in this manner different anthropogenic contributions.
iv
The contemporary carbon throughout our sampling campaign in the Lephalale District
has been measured to be approximately 53% of carbon aerosol. As many studies have been
performed of contemporary carbon and fossil carbon, no other contemporary and fossil carbon
source assessment method provides the definitive results that can be obtained from radiocarbon
measurements.
PIXE analysis for the determination of the elemental composition of particulate matter
in samples near the Medupi coal-fired power station in the Lephalale District was also
performed for 6 elements, namely, K, Ca, Ti, Mn, Fe, and Zn. In the samples that were analyzed
the particulate matter concentrations did not exceed the air quality standards regulation at
Lephalale. The recommended daily limit air quality standard by South African legislation is 75
µg/m3.
Enrichment Factor (EF) analysis of soil with respect to Fe shows anomalously high
values for Zn.
AMS was also applied to archaeological studies of early herding camps of the khoe
khoe people at Kasteelberg, situated on the southwest coast in South Africa, and are among the
best preserved sites of their kind in the world. Sea-shell samples from the Kasteelberg B (KBB)
site have been dated with AMS at Lawrence Livermore National Laboratory (LLNL) in an
effort to elucidate the relationship between the herder-foragers of the inland and shoreline sites
in terms of migration patterns. The radiocarbon dates obtained are in general agreement with
the other studies that have been performed on the site, and show that the ages of artifacts are
less than 2000 years. The samples for this study originate from various well defined
stratigraphic-levels at square A3 at KBB. It was evident from excavation that the artefacts seem
to be of the same period and there is no evidence of mixing from different stratigraphic layers.
v
Radiocarbon dates were calibrated using Calib 6.1 and each was corrected for marine
reservoir effect. The date range between the earliest and most recent dates that were obtained
span gap is approximately 400 years from AD 825 to AD 1209. The majority of the radiocarbon
dates of the KBB site belong to dates of 1002-1100 AD, the other few belong to 825-958 AD,
and the last single date of 1209 AD. The new AMS dates from this work suggest the high
probability that indeed there was a hiatus between the two occupations designated as lower and
the upper KBB. The significant changes seen in material culture styles as well as in the nature
of occupation and change in accumulation rate of deposits therefore do not necessarily indicate
a cultural replacement caused by the arrival of a new population. This implies that the
occupants of lower KBB may also have been Khoe-speakers, and not local San. / GR2018
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U-Pb age and Hf isotopic study of detrital zircons from the Liaohe Group: constraints on the evolution of theJiao-Liao-Ji Belt, North China cratonLuo, Yan, 羅彥 January 2005 (has links)
published_or_final_version / abstract / Earth Sciences / Doctoral / Doctor of Philosophy
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Permian-Triassic stable isotope stratigraphy of AustraliaMorante, Richard. January 1996 (has links)
Thesis (Ph.D.) -- Macquarie University, School of Earth Sciences, 1996. / "September, 1995" Bibliography: leaves 171-183.
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Investigating North Atlantic ocean circulation using radiogenic isotopesRoberts, Natalie Laura January 2013 (has links)
No description available.
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Strontium isotopes in Jurassic and Early Cretaceous seawaterJones, Charles Edward January 1992 (has links)
The collection and analysis of a large number of belemnites and oysters with excellent biostratigraphic and diagenetic control has resulted in a highly detailed determination of the seawater Sr-isotope curve through the Jurassic and Early Cretaceous. The new data confirm the broad trends established by previous work, but the much sharper resolution of the new data allows the application of Sr-isotope stratigraphy with an optimal stratigraphic resolution of ± 1 to 4 ammonite subzones (± 0.5 to 2 Ma). The data show a general decline from the Hettangian (Early Jurassic) to a minimum in the Callovian and Oxfordian (Middle/Late Jurassic). This is followed by an increase through the Kimmeridgian (Late Jurassic) to a plateau reached in the Barremian (Early Cretaceous). In addition, there are major negative excursions in the Pliensbachian/Toarcian (Early Jurassic) and Aptian/Albian (Early Cretaceous). Stable isotope data collected from belemnites and oysters have resulted in the most extensive Jurassic δ<sup>13</sup>C and δ<sup>18</sup>O database to date. While both the carbon and oxygen data appear to give reasonable marine signals, the scatter in the data suggests that future research must document possible biological fractionation effects and develop better indicators for the diagenetic alteration of 613C and 6i 8O. The final chapter documents an unexpected correlation between sudden shifts in the Sr-isotope curve, the occurrence of positive 513C excursions, and the eruption of flood basalts. In the Jurassic and Cretaceous there is a correlation in time between sudden downward shifts in the Sr-isotope curve (Pliensbachian, Aptian, Cenomanian/Turonian), the occurance of positive 613C excursions, and the eruption of flood basalts. Each of these major downward shifts in the Sr-isotope curve is followed by a sudden upward shift, which although associated with a positive 613C excursion is not associated with an episode of flood basalt volcanism. In the Cenozoic the Sr-isotope curve no longer displays downward shifts, but the correlation continues between the occurrence of flood basalts and positive 513C excursions. Several lines of evidence suggest that the eruption of flood basalts is associated with pulses of hydrothermal activity, and that this hydrothermal activity brings about the conditions necessary for the genesis of carbon-burial events.
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Permian-Triassic stable isotope stratigraphy of AustraliaMorante, Richard January 1996 (has links)
"September, 1995" / Thesis (Ph.D.) -- Macquarie University, School of Earth Sciences, 1996. / Bibliography: leaves 171-183. / Introduction -- Australian ð¹³Corg-isotope profiles about the Permian-Triassic (P/TR) boundary -- Strontium isotope seawater curve in the late Permian of Australia -- ð¹³Cco₃ AND ð¹⁸Oco₃ seawater profiles through the Permian-Triassic of Australasia -- Paleomagnetic stratigraphy about the Permian/Triassic boundary in Australia -- Synthesis. / The Permian-Triassic boundary mass extinction is the largest in the Phanerozoic and therefore is the major event in the Phanerozoic. The mass extinction cause is problematical but studying global geochemical and geophysical signatures about the Permian-Triassic boundary can provide insights into the cause of the mass extinction. Global events about the Permian-Triassic boundary are marked by changes in: ð¹³C values of carbon ; ⁸⁷Sr/⁸⁶Sr in unaltered marine calcite ; magnetic polarity. -- This study aims to identify these features in the sedimentary record and to test the ca libration of the Australian biostratigraphical schemes to the global geological timescale. The following features are found in the Permian-Triassic sediments of Australia: a ð¹³Corg in Total Organic Carbon excursion in 12 marine and nonmarine sections from Northwest to Eastern Australia ; a ⁸⁷Sr/⁸⁶Sr minimum in a composite section mainly from the Bowen Basin ; a magnetic polarity reversal in the Cooper Basin, central Australia. The Australian sections are thus time correlated, as follows: The negative ð¹³Corg excursion indicates the Permian-Triassic boundary and occurs: 1) in Eastern and Central Australia at the change from coal measures to barren measures with red beds at the beginning of the Early Triassic coal gap; 2) in Northwest Australia about the boundary between the Hyland Bay Formation and the Mount Goodwin Formation in the Bonaparte Basin and at the boundary between the Hardman Formation and the Blina Shale in the Canning Basin. The base of the negative ð¹³Corg excursion lies at or near the base of the Protohaploxypinus microcorpuspalynological zone. The ⁸⁷Sr/⁸⁶Sr minimum determined about the Guadalupian/Ochoan stage boundary in North America is found in the Bowen Basin about the boundary between the Ingelara and Peawaddy Formations. The ð¹³Corg excursion in the Cooper Basin is near a magnetic reversal within the Permo-Triassic mixed superchron. The implications of these findings include: confirmation of the traditional placement of the Permian-Triassic boundary at the coal measures/barren measures with redbeds boundary in Eastern Australia ; the linking of the the Permian-Triassic boundary to a mass extinction of plant species on land and the beginning of the Triassic coal gap indicated by the Falcisporites Superzone base that is coincident with the negative ð¹³Corg excursion ; a mass extinction causal model that links the ⁸⁷Sr/⁸⁶Sr minimum determined about the Guadalupian/Ochoan stage boundary to a fall in sealevel that led to changing global environmental conditions. The model invokes greenhouse warming as a contributing cause of the mass extinction. / Mode of access: World Wide Web. / xii, 183 leaves ill., maps
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Stable isotopes and chemistry of water as source indicators of aquifer recharge and contaminationThurnblad, Timothy William. January 1982 (has links) (PDF)
Thesis (M.S. - Hydrology and Water Resources)--University of Arizona, 1982. / Includes bibliographical references (leaves 159-162).
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