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Bosch, D.
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- PublicationRestrictedGeodynamic implications of deep mantle upwelling in the source of Tertiary volcanics from the Veneto region (South-Eastern Alps)(2003)
; ; ; ; ; ; ; ;Macera, P.; Dipartimento di Scienze della Terra, Universita’ di Pisa ;Gasperini, D.; Dipartimento di Scienze della Terra, Universita’ di Pisa ;Piromallo, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Blichert-Toft, J.; Ecole Normale Superieure, Lyon ;Bosch, D.; Universite ‘‘Montpellier 2", Montpellier ;Del Moro, A.; Istituto di Geoscienze e Georisorse, C.N.R., Pisa ;Martin, S.; Dipartimento di Chimica Fisica Matematica, Universita` Insubria, Como; ; ; ; ; ; Major and trace element and Sr–Nd–Hf–Pb isotopic data for the most primitive Tertiary lavas from the Veneto region (South-Eastern Alps, Italy) show the typical features of HIMU hotspot volcanism, variably diluted by a depleted asthenospheric mantle component (87Sr/86Sri=0.70306–0.70378; "Ndi=+3.9 to +6.8; "Hfi=+6.4 to +8.1, 206Pb/204Pbi=18.786–19.574). P-wave seismic tomography of the mantle below the Veneto region shows the presence of low-velocity anomalies at depth, which is consistent with possible upwellings of plume material. Between the depths of 100–250 km the velocity anomalies are approximately 2–2.5% slower than average, implying a temperature excess of about 220–280 K, in agreement with estimates for other mantle plumes in the world. In this context, the Veneto volcanics may represent the shallow expression of a mantle upflow. The presence of a HIMU-DM component in a collision environment has significant geodynamic implications. Slab detachment and ensuing rise of deep mantle material into the lithospheric gap is proposed to be a viable mechanism of hotspot magmatism in a subduction zone setting.242 23