View source for Are subduction zones actually mantle wedges upduction? ? A new interpretation of the Mediterranean arcs

{{Infobox paper
| title = Are subduction zones actually mantle wedges 
upduction? ? A new interpretation of the 
Mediterranean arcs
| author = [[Giancarlo Scalera]]
| published = 2005
| journal = [[Geophysical Research Abstracts]]
| volume = [[7]]
| number = [[07211]]
}}

==Abstract==

Recent reviews of results of different group working to large scale seis-   mic tomography show that the prolongation of the rigid/colder lithospheric slab up   to the core mantle boundary, if any, is not clearly recognizable (Fukao et al., 2001;   Romanowitz, 2003). Often the tomographic images of these high-velocity bodies   smoothly become horizontal ? at the deep of the 640 km discontinuity ? and often   they continue to bend slightly coming back toward the upper mantle.   Because the strict similarity of some Italian and Mediterranean tectonic situations to   the East Asia tectonics ? arcs, trenches, Wadati-Benioff zones, volcanic and seismic   activities, and the above mentioned horizontal bending of the alleged lithospheric slab   ?, many clues are examined in search of new interpretations of the Mediterranean ge-   ological and observational evidence, with the aim to find solutions that are exportable   to the problems of the circumpacific arc-trench zones.   The inspection of facts coming from surface geology, magmatism, geochemistry, dif-   ferent method tomographies, etc., is at variance with the alleged Africa-Eurasia con-   vergence. The clues for rifting prevail on those for compression, and many tectonic   situations previously interpreted as due to plates? collision, are associated or mixed   to rifting evidence. The high velocity bodies characterizing the Wadati-Benioff zone   connects gently with large extents of anomalous high velocity mantle trapped in the   transition zone. Consequently the proposal is put forward that limitate amount of up-   rising ? or upduction ? of mantle material wedges ? driven by isostasy ? between two   separating lithospheric plates could be a new work hypothesis (Scalera, 2004a,b).   Because on an expanding Earth the Mediterranean region has had ever a little lat-  itudinal extension, it is possible in this view, to identify as Mediterranean phases of   opening also the Paleo Tethys and Neo Tethys currently alleged ?closures?, which have   added to the Proterozoic nuclei the Variscan and Alpine terranes respectively. These   phases and their orogens has to be considered as extensional phases ? in which con-   tinentalisations of narrow basins have happened ? and the added terranes of African   provenance (e.g. the Adriatic fragment) should be regarded as fragments left behind   by the going away continental Africa. In this sense, considering the ongoing process   of opening as having Proterozoic origin, it is possible to speak of the Mediterranean   as a slowly nascent ocean, but also ? paradoxically ? as a very old ocean.   More generally, this way of reasoning could be extended to Middle East paleo-   tectonics and to Asia (Scalera, 2001), checking that the greater proximity of Eurasia   and Gondwana on a smaller globe obtainable in the expanding Earth framework can   resolve many of the outstanding problems of paleogeography.   Future aim of this research line is to better describe the different phases of opening   of the several Mediterranean basins, taking into account the older age of eastern Lev-   antine seafloor, the intermediate age of western Mediterranean and the young age of   the Tyrrhenian sea, all in a framework in which Africa is slowly escaping away from   Europe.

[[Category:Scientific Paper|subduction zones actually mantle wedges upduction new interpretation mediterranean arcs]]

[[Category:Cosmology|subduction zones actually mantle wedges upduction new interpretation mediterranean arcs]]