From late Cretaceous to present time, an extensive magmatic activity developed both in Europe and northern Africa, showing a progressive transition with time from calc-alkaline to Na-rich alkaline features in areas tightly connected with subduction systems (Morocco, Algeria, Tunisia, Spain, western Italy), while Na-rich basalts and basanites, with minor tholeiitic volcanics, occur at extensional tectonic settings, both associated or not to orogenic dynamics (Valencia trough, Pannonian, Alboran, Tyrrhenian, and Aegean basins, Pantelleria-Etna-Iblean area, Veneto Province, Cenozoic Rift System). The widespread alkaline magmatism in the European and circum Mediterranean area shows a uniform OIB-HIMU-type signature which has been previously ascribed to a plume-related european astenospheric reservoir (EAR) standing at less than 400 km depth in the upper mantle (Wilson and Downes, 1991). In the same area a large low seismic velocity zone below 900 km depth is evident by tomographic images from whole mantle models. The mantle transition zone under central-western Europe and Mediterranean is instead characterized by high velocity anomaly, while the top most mantle is again dominated by a low-velocity zone on a large scale (Goes et al., 1999; Piromallo and Morelli, 2003). The origin of this mantle geochemical/geophysical anomaly has been related to the Mesozoic super-plume activity centered at Madeira-Canary-Cape Verde (MCCV), where the HIMU component appears to have its purest fingerprint (Hoernle et al., 1995; Wilson, 1997; Oyarzun et al., 1997; Gasperini et al., 2003).Achievable interpretations of any relationship between present seismic anomalies and alkaline magmatism in this wide area are restricted to recent time (Hoernle et al., 1995; Goes et al., 1999), since older geochemical and geophysical features depend on the paleo-position of each magmatic center toward the south-west. Assuming that a common and primary mantle plume has been upwelling beneath the present MCCV since at least 65-70 Ma, using a hot spot reference frame, we projected that in the early Cenozoic the theoretical positions of the European magmatic centers might outline the old plume head size. The shallower large-scale swell of this plume had been subsequently dragged by motion of Eurasia towards the northeast and trapped above the transition zone, favoring plume related volcanism if and where local extensiona tectonics and slab rupture occur (Macera et al., 2003)

Recent hot spot volcanism in the European and Mediterranean area

MACERA, PATRIZIA;
2004-01-01

Abstract

From late Cretaceous to present time, an extensive magmatic activity developed both in Europe and northern Africa, showing a progressive transition with time from calc-alkaline to Na-rich alkaline features in areas tightly connected with subduction systems (Morocco, Algeria, Tunisia, Spain, western Italy), while Na-rich basalts and basanites, with minor tholeiitic volcanics, occur at extensional tectonic settings, both associated or not to orogenic dynamics (Valencia trough, Pannonian, Alboran, Tyrrhenian, and Aegean basins, Pantelleria-Etna-Iblean area, Veneto Province, Cenozoic Rift System). The widespread alkaline magmatism in the European and circum Mediterranean area shows a uniform OIB-HIMU-type signature which has been previously ascribed to a plume-related european astenospheric reservoir (EAR) standing at less than 400 km depth in the upper mantle (Wilson and Downes, 1991). In the same area a large low seismic velocity zone below 900 km depth is evident by tomographic images from whole mantle models. The mantle transition zone under central-western Europe and Mediterranean is instead characterized by high velocity anomaly, while the top most mantle is again dominated by a low-velocity zone on a large scale (Goes et al., 1999; Piromallo and Morelli, 2003). The origin of this mantle geochemical/geophysical anomaly has been related to the Mesozoic super-plume activity centered at Madeira-Canary-Cape Verde (MCCV), where the HIMU component appears to have its purest fingerprint (Hoernle et al., 1995; Wilson, 1997; Oyarzun et al., 1997; Gasperini et al., 2003).Achievable interpretations of any relationship between present seismic anomalies and alkaline magmatism in this wide area are restricted to recent time (Hoernle et al., 1995; Goes et al., 1999), since older geochemical and geophysical features depend on the paleo-position of each magmatic center toward the south-west. Assuming that a common and primary mantle plume has been upwelling beneath the present MCCV since at least 65-70 Ma, using a hot spot reference frame, we projected that in the early Cenozoic the theoretical positions of the European magmatic centers might outline the old plume head size. The shallower large-scale swell of this plume had been subsequently dragged by motion of Eurasia towards the northeast and trapped above the transition zone, favoring plume related volcanism if and where local extensiona tectonics and slab rupture occur (Macera et al., 2003)
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/83453
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