Publication Date:
2017-04-04
Description:
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.
Description:
Published
Description:
563–590
Description:
3.3. Geodinamica e struttura dell'interno della Terra
Description:
JCR Journal
Description:
reserved
Keywords:
trace-element
;
isotopic composition
;
alkali basalts
;
central-Europe
;
slab break-off
;
plume
;
04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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