Options
A new interpretation of the Mediterranean arcs: Mantle wedge intrusion instead of subduction
Language
English
Status
Published
Peer review journal
Yes
Title of the book
Issue/vol(year)
2005
Publisher
Società Geologica Italiana
Pages (printed)
129-147
Issued date
November 1, 2005
Abstract
Because of the close similarity of some Italian and Mediterranean
tectonic situations to the East Asia tectonics – arcs, trenches, Wadati-
Benioff zones, volcanic and seismic activities, and a typical horizontal
bending of the alleged lithospheric slab –, many clues are examined in
search of new interpretations of the Mediterranean geological and
observational evidence, with the aim of finding solutions that are
exportable to the problems of the circumpacific arc-trench zones.
The facts coming from surface geology, magmatism, geochemistry,
different method tomographies, etc., are at variance with the
alleged Africa-Eurasia convergence. The clues for rifting prevail over
those for compression, and many tectonic situations previously
interpreted as due to plate collisions, are associated to or mixed to
rifting evidence. The proposal is put forward that uprising of mantle
material wedges between two separating lithospheric plates could be
a new working hypothesis.
On an expanding Earth the region interposed between Eurasia
and Africa has always had a smaller latitudinal extension with
respect to the large Paleo Tethys and Neo Tethys appearing on constant-
radius paleogeographical reconstructions. It is then possible,
in the expanding Earth view, also to identify as phases of opening
the Paleo Tethys and Neo Tethys currently alleged ‘closure’, which
has added to the Proterozoic nuclei the Variscan and Alpine terranes
respectively. These phases and their orogens have to be considered
as extensional phases, and the added terranes of African provenance
(e.g. the Adriatic fragment) should be regarded as fragments left
behind as continental Africa moved away. 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.
tectonic situations to the East Asia tectonics – arcs, trenches, Wadati-
Benioff zones, volcanic and seismic activities, and a typical horizontal
bending of the alleged lithospheric slab –, many clues are examined in
search of new interpretations of the Mediterranean geological and
observational evidence, with the aim of finding solutions that are
exportable to the problems of the circumpacific arc-trench zones.
The facts coming from surface geology, magmatism, geochemistry,
different method tomographies, etc., are at variance with the
alleged Africa-Eurasia convergence. The clues for rifting prevail over
those for compression, and many tectonic situations previously
interpreted as due to plate collisions, are associated to or mixed to
rifting evidence. The proposal is put forward that uprising of mantle
material wedges between two separating lithospheric plates could be
a new working hypothesis.
On an expanding Earth the region interposed between Eurasia
and Africa has always had a smaller latitudinal extension with
respect to the large Paleo Tethys and Neo Tethys appearing on constant-
radius paleogeographical reconstructions. It is then possible,
in the expanding Earth view, also to identify as phases of opening
the Paleo Tethys and Neo Tethys currently alleged ‘closure’, which
has added to the Proterozoic nuclei the Variscan and Alpine terranes
respectively. These phases and their orogens have to be considered
as extensional phases, and the added terranes of African provenance
(e.g. the Adriatic fragment) should be regarded as fragments left
behind as continental Africa moved away. 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.
Type
article
File(s)
Loading...
Name
Mediterran nascent Soc.Geol.It. 2005.pdf
Size
4.95 MB
Format
Adobe PDF
Checksum (MD5)
c0effff2ec3efaa8c6ef8edf1a80a104