40 research outputs found

    Palaeomagnetic determination of emplacement temperature of Vesuvius AD 79 pyroclastic deposits

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    The city of Herculaneum was buried under 20 m of pyroclastic deposits during the AD 79 eruption of Vesuvius, whose crater is only 7 km to the east. These deposits have been interpreted as the deposits of mudflows or hot pyroclastic flows. Maury's studies of incinerated wood in Herculaneum demonstrate heating to at least 400° C. We have studied the variation of remanent magnetism with temperature for specimens taken from the deposits, including specimens of the matrix material and of embedded lithic fragments. We conclude that the temperature of the deposit at emplacement is unlikely to have been greater than 400° C, which further supports the interpretation of the pyroclastic deposits at Herculaneum as largely ignimbrites (hot pyroclastic flow deposits)

    Fossils from Mille-Logya, Afar, Ethiopia, elucidate the link between Pliocene environmental changes and Homo origins

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    Several hypotheses posit a link between the origin of Homo and climatic and environmental shifts between 3 and 2.5 Ma. Here we report on new results that shed light on the interplay between tectonics, basin migration and faunal change on the one hand and the fate of Australopithecus afarensis and the evolution of Homo on the other. Fieldwork at the new Mille-Logya site in the Afar, Ethiopia, dated to between 2.914 and 2.443 Ma, provides geological evidence for the northeast migration of the Hadar Basin, extending the record of this lacustrine basin to Mille-Logya. We have identified three new fossiliferous units, suggesting in situ faunal change within this interval. While the fauna in the older unit is comparable to that at Hadar and Dikika, the younger units contain species that indicate more open conditions along with remains of Homo. This suggests that Homo either emerged from Australopithecus during this interval or dispersed into the region as part of a fauna adapted to more open habitats.info:eu-repo/semantics/publishedVersio

    Paleomagnetic Evidence For Rotation Of Sardinia During Early Miocene

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62818/1/243281a0.pd
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