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| Andrews, John T.; Kristjansdottir, Greta B.; Eberl, Dennis D.; Jennings, Anne E.. |
| This paper re-evaluates how well quantitative x-ray diffraction (qXRD) can be used as an exploratory method of the weight percentage (wt%) of volcaniclastic sediment, and to identify tephra events in marine cores. In the widely used RockJock v6 software programme, qXRD tephra and glass standards include the rhyodacite White River tephra (Alaska), a rhyolitic tephra (Hekla-4) and the basaltic Saksunarvatn tephra. Experiments of adding known wt% of tephra to felsic bedrock samples indicated that additions >= 10 wt% are accurately detected, but reliable estimates of lesser amounts are masked by amorphous material produced by milling. Volcaniclastic inputs range between 20 and 50 wt%. Primary tephra events are identified as peaks in residual qXRD glass wt%... |
| Tipo: Text |
Palavras-chave: X-ray diffraction; Tephras; Iceland Holocene. |
| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00265/37578/36528.pdf |
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| Stoner, Joseph S.; Jennings, Anne; Kristjansdottir, Greta B.; Dunhill, Gita; Andrews, John T.; Hardardottir, Jorunn. |
| We report the intercalibration of paleomagnetic secular variation (PSV) and radiocarbon dates of two expanded postglacial sediment cores from geographically proximal, but oceanographically and sedimentologically contrasting settings. The objective is to improve relative correlation and chronology over what can be achieved with either method alone. Core MD99-2269 was taken from the Hunafloaall Trough on the north Iceland shelf. Core MD99-2322 was collected from the Kangerlussuaq Trough on the east Greenland margin. Both cores are well dated, with 27 and 20 accelerator mass spectrometry (14)C dates for cores 2269 and 2322, respectively. Paleomagnetic measurements made on u channel samples document a strong, stable, single-component magnetization. The... |
| Tipo: Text |
Palavras-chave: Holocene; Paleomagnetic secular variation; Radiocarbon dating. |
| Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00233/34436/32934.pdf |
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