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Il metamorfismo dei depositi clastici triassici di Lerici-S.Terenzo, del Passo del Cerreto, di Collagna (Val di Secchia) e di Soraggio (Appennino Settentrionale)
No full textStructure of the Deep Freeze Range - Eisenhower Range of the Wilson Terrane (North Victoria Land Antarctica): emplacement of magmatic intrusions in the Early Palaeozoic deformed margin of the East Antarctic Craton
No full textIn North Victoria Land (Antarctica), the Wilson Terrane is a portion of the palaeomargin of the East
Antarctic Craton, deformed during the Late Cambrian-Early Ordovician Ross Orogeny. Crustal deformation,
from westward subduction of the palaeo Pacific plate and terrane accretion on this palaeomargin, gave rise to
the development of a transpressive fold belt and a wide magmatic arc. In the inner portion ofthe Wilson Terrane,
(Deep Freeze Range-Eisenhower Range) a large portion of this magmatic arc is made up of intrusions and dyke
systems. Intrusive rocks range from large unfoliated plutons to well foliated sheet intrusions emplaced in low
and medium-high grade metamorphic rocks respectively. Field and structural data on intrusive rocks and
metamorphic host rocks, coupled with parameters relative to deformation mechanism and magmatic processes
(crystallization and cooling) rates, make it possible to outline an episode of diffuse synkinematic magmatism
in the Wilson Terrane. The emplacement of intrusions in both the middle and upper crust was coeval and related
to the development of transpressional and transtensional structures along dextral strike-slip shear zones.
Furthermore the development of foliated or unfoliated fabrics is related to competition between rates of
deformation and magmatic processes, which is a function of the thermal state of the host rock
Late Hercynian shear zones in Sardinia
No full textIn the past few years two main late Hercynian shear zones have been identified in Sardinia: the Mount Grighini shear zone in the centre of the island and the Posada Valley shear zone in the north. Both are dextral wrench shear zones, affecting the Hercynian basement during the Late Carboniferous, and characterized by a simple shear deformation with an evolution from cataclastic to ultramylonitic rocks. The meso-and microstructural deformation features are discussed here. On the basis of these, two maps of the different deformative zones within the shear zones have been prepared and both displacements have been calculated. An attempt has also been made to correlate with other late Hercynian shear zones in continental Europe on the basis of common features and geological constraints
P-T evolution and age of the Barrovian metamorphism in the MCT Zone of the Arun Valley, E Nepal
No full textGeology and tectonomagmatic evolution of the eastern Himalaya along the Chomolungma- Makalu transect
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Synkinematic emplacement of some Granite Harbour Intrusives: field and microstructural observation from Dry Valleys to Mountainer Range (Victoria Land, Antartica)
No full textPreliminary geological map and description of the Himalayan-Karakorum junction in Chom Lungma to Turmik area (Baltistan, northern Pakistan)
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