Publication Date:
2017-04-04
Description:
One of the most challenging issues about the Tertiary–Quaternary alkaline magmatism spreading across the Euro-Mediterranean region is the
assessment of both the nature of its mantle source and the mechanism responsible for the common HIMU-like (High μ=high 238U/204Pb)
character of erupted lavas, enduring over about 100 million years in diverse tectonic environments. In this paper we try to reconcile geochemical
and geophysical data through a multidisciplinary investigation on geochemistry, timing and locations of the main Na-rich alkaline volcanic
centers, seismic tomographic images and plate kinematics. We propose that the common component of the Euro-Mediterranean mantle derives
from a contamination episode triggered by the rise of the Central Atlantic Plume (CAP) head. Plate reconstruction shows that at late Cretaceous-
Paleocene time the oldest magmatic centers of the Euro-Mediterranean region were located more than 2000 km SW of their present day position,
in proximity of the CAP hot spot location, where seismic tomography detects a broad low seismic velocity region in the lower mantle. The northeastward
migration of the Eurasian and African plates could have involved also part of the CAP contaminated mantle, which moved in the same
direction being coupled to the lithospheric plates, thus explaining the presence of geochemically-uniform material spread in the sub-lithospheric
Euro-Mediterranean mantle. During the Tertiary, regional-scale convection and related processes such as rifting, back-arc spreading, slab
detachment/windows, may have favored upwelling and partial melting of the frayed plume head material via adiabatic decompression, shaping the
spatial and temporal distribution of HIMU-like volcanics. The growing supply of subducted lithosphere may explain as well the increase of crustal
isotopic signatures of alkaline magmas with time. In our opinion, the Euro-Mediterranean upper mantle contamination can be eventually related to
a global event occurred during the Cretaceous as a consequence of a mantle avalanche caused by the Tethys closure.
Description:
MIUR 2005-2007, prot. n. 2005055415_002, Poli G.
Description:
Published
Description:
15–27
Description:
3.3. Geodinamica e struttura dell'interno della Terra
Description:
JCR Journal
Description:
partially_open
Keywords:
Cenozoic HIMU–OIB volcanism
;
Euro-Mediterranean mantle
;
geochemistry
;
mantle tomography
;
plate kinematics
;
04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
