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Koeberl, C.; Huber, Heinz

doi:10.1023/a:1006754409429

Cited by 29 publications

(4 citation statements)

References 9 publications

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“…Precision of the analyses were usually on the order of 5-15 rel%. Further details of the procedure, as well as on the instrumentation, are given in Koeberl and Huber (2000).…”

Section: Matemals and Methodsmentioning

confidence: 99%

Impact and extinction in remarkably complete Cretaceous-Tertiary boundary sections from Demerara Rise, tropical western North Atlantic

MacLeod

Whitney

Huber

et al. 2007

Geological Society of America Bulletin

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Ocean Drilling Program (ODP) Leg 207, on the Demerara Rise in the western tropical North Atlantic, recovered multiple Cretaceous-Paleogene boundary sections containing an ejecta layer. Sedimentological, geochemical, and paleontological changes across the boundary closely match patterns expected for a mass extinction caused by a single impact. A normally graded, ~2-cmthick bed of spherules that is interpreted as a primary air-fall deposit of impact ejecta occurs between sediments of the highest Cretaceous Plummerita hantkeninoides foraminiferal zone and the lowest Paleogene PO foraminiferal zone. There are no other spherule layers in the section. In addition to extinction of Cretaceous taxa, foraminiferal abundance drops from abundant to rare across the boundary. Ir concentrations reach a maximum of-1.5 ppb at the top of the spherule bed, and the Ir anomaly is associated with enrichment in other siderophile elements. We attribute the unusually well-preserved and relatively simple stratigraphy to the fact that Demerara Rise was close enough (-4500 km) to the Chicxulub impact site to receive-2 cm of ejecta, yet was far enough away (and perhaps sheltered by the curve of northern South America) to have been relatively unaffected by impact-induced waves.

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“…Precision of the analyses were usually on the order of 5-15 rel%. Further details of the procedure, as well as on the instrumentation, are given in Koeberl and Huber (2000).…”

Section: Matemals and Methodsmentioning

confidence: 99%

Impact and extinction in remarkably complete Cretaceous-Tertiary boundary sections from Demerara Rise, tropical western North Atlantic

MacLeod

Whitney

Huber

et al. 2007

Geological Society of America Bulletin

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“…We measured the concentrations of 43 elements by neutron activation analysis and x-ray fluorescence spectrometry, and we measured the Ir content by multiparameter coincidence spectrometry after neutron activation (10). Ir anomalies were found at the base of all cap carbonates after the Marinoan and Sturtian glaciations in the Nguba and Kundelungu Groups at Kipushi, as well as after the Sturtian glacial deposits in the Nguba Group at Chambishi.…”

mentioning

confidence: 99%

“…To broaden taxonomic comparisons and supplement limited sample size, our analysis also included endocasts of the skulls of specimen Sts 5 (A. africanus), specimen KNM-WT 17000 (Paranthropus aethiopicus), 10 humans, 10 gorillas, 18 chimpanzees (9), an adult female pygmy, and five H. erectus. Our virtual cranial capacity estimate for LB1 is 417 cm 3 (10). Virtual endocasts of the microcephalic, modern woman, H. erectus, and chimpanzee were scaled to 417 cm 3 to facili-tate shape comparisons ( Fig.…”

mentioning

confidence: 99%

Estimating Duration and Intensity of Neoproterozoic Snowball Glaciations from Ir Anomalies

Bodiselitsch

Koeberl

Master

et al. 2005

Science

115

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The Neoproterozoic glaciations supposedly ended in a supergreenhouse environment, which led to rapid melting of the ice cover and precipitation of the so-called cap carbonates. If Earth was covered with ice, then extraterrestrial material would have accumulated on and within the ice and precipitated during rapid melting at the end of the glaciation. We found iridium (Ir) anomalies at the base of cap carbonates in three drill cores from the Eastern Congo craton. Our data confirm the presence of extended global Neoproterozoic glaciations and indicate that the duration of the Marinoan glacial episode was at least 3 million, and most likely 12 million, years.

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“…Em virtude de apenas eventos em coincidência serem selecionados, esse método apresenta também a vantagem de redução de algumas estruturas espectrais -como a gerada por espalhamento Compton -possibilitando a diminuição do limite de detecção de alguns elementos [18,[22][23][24] provenientes de amostras de origem ambiental, geológica ou biológica. Outra característica favorável de medições por CINAAé a diminuição do Raio X contínuo, denominado radiação de bremsstrahlung, proveniente da interação das partículas β com a matéria.…”

Section: Introductionunclassified

Uso de sistema de coincidência gama-gama associado à espectroscopia simples em medidas de análise por ativação neutrônica

Junior¹,

Souza²

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In this study was the developed a γγ acquisition system that make possible to perform Neutron Activation Analysis by single gamma spectroscopy and coincidence γγ spectroscospy simultaneously for the elements As, Co, Cs, La, Sc, Se e Sm. In order to achieve this main goal preliminary measurements in γγ acquisition systems with analogical and digital instrumentation were performed to check the efficiency of technique through measurements of synthetic standard and certified reference material. These measurements also helped to choose the most suitable instrumentation for the development of the acquisition system in the Applied Nuclear Physics Laboratory (LFNA) located at IPEN. The developed system is composed by a CAEN v1724 digitizer board and two hyperpure Germanium detectors. The data acquisition is controled by MC2Analyzer software, which provide raw data of energy and time information of the recorded pulses.Two softwares for data reduction that allow the set the coincident events from single spectra were developed: DPP which prepare the data to be analyzed with softwares for bidimensional espectra.; and AnalisaCaen which handle the data to be analyzed with softwares for single spectra. Determination of the concentration for some elements in certified reference materials and sytnhetic standards were performed applying the conventional and coincidence Neutron Activation Analysis methods. Accuracy and precision of the results obtained by Instrumental Neutron Activation Analysis and Coincidence Instrumental Neutron Activation Analysis were performed by E n score criteria. The results obtained with this system allowed to check the reliability on the determination for the elements As, Co, Cs, La, Sc, Se and Sm. In some cases the concentration results obtained with coincidence measurements were better than the results from single spectroscopy.

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Cited by 29 publications

References 9 publications

Impact and extinction in remarkably complete Cretaceous-Tertiary boundary sections from Demerara Rise, tropical western North Atlantic

Impact and extinction in remarkably complete Cretaceous-Tertiary boundary sections from Demerara Rise, tropical western North Atlantic

Estimating Duration and Intensity of Neoproterozoic Snowball Glaciations from Ir Anomalies

Uso de sistema de coincidência gama-gama associado à espectroscopia simples em medidas de análise por ativação neutrônica

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