Structural, petrological and geochronological data from the Variscan chain of northern Sardinia a... more Structural, petrological and geochronological data from the Variscan chain of northern Sardinia are discussed, with the aim to improve our knowledge on the tectono-metamorphic evolution of the northern Sardinian basement and its role in the tectonic puzzle of the southern Variscan massifs. In northern Sardinia, which corresponds to the Inner zone of the chain, the metamorphic grade rapidly increases towards the NE from biotite to sillimanite+K-feldspar zone. The highest grade rocks cropping out in the Migmatite zone reached amphibolite facies conditions in the sedimentary and igneous-derived migmatite and eclogite/granulite facies in the enclosed metabasite lenses. Evidence of HP metamorphism has also recently been found more to the south in micaschist from the garnet zone. The D 1 deformation can be observed in the southern part of the Inner zone, whereas, moving progressively northwards, the D 2 deformation progressively obliterates the previous foliation. The other, less pervasiv...
The Kali Gandaki valley in the Central Himalaya is flanked by the eight thousand meter high Annap... more The Kali Gandaki valley in the Central Himalaya is flanked by the eight thousand meter high Annapurna and Dhaulagiri massifs forming the deepest gorge in the world. It offers an invaluable opportunity to directly observe a cross section through the continental crust involved in the Himalayan orogen. The north-south trend of the valley runs almost perpendicular to the dominant regional strike and cross cuts the major tectonic units that comprise the Himalaya including the Lesser Himalayan Sequence, the Greater Himalayan Sequence and the Tethyan Sedimentary Sequence. The valley is easily accessible compared to many other sections across the belt and its history as a popular trekking route ensures services and lodging that are often not available elsewhere. We propose a one-week itinerary across the low metamorphic grade Proterozoic quartzites of the Lesser Himalayan Sequence in the south, through the high-grade, migmatitic metamorphic core of the Greater Himalayan Sequence to the unme...
Structural, petrological and geochronological data from the Variscan chain of northern Sardinia a... more Structural, petrological and geochronological data from the Variscan chain of northern Sardinia are discussed, with the aim to improve our knowledge on the tectono-metamorphic evolution of the northern Sardinian basement and its role in the tectonic puzzle of the southern Variscan massifs. In northern Sardinia, which corresponds to the Inner zone of the chain, the metamorphic grade rapidly increases towards the NE from biotite to sillimanite+K-feldspar zone. The highest grade rocks cropping out in the Migmatite zone reached amphibolite facies conditions in the sedimentary and igneous-derived migmatite and eclogite/granulite facies in the enclosed metabasite lenses. Evidence of HP metamorphism has also recently been found more to the south in micaschist from the garnet zone. The D 1 deformation can be observed in the southern part of the Inner zone, whereas, moving progressively northwards, the D 2 deformation progressively obliterates the previous foliation. The other, less pervasiv...
The Kali Gandaki valley in the Central Himalaya is flanked by the eight thousand meter high Annap... more The Kali Gandaki valley in the Central Himalaya is flanked by the eight thousand meter high Annapurna and Dhaulagiri massifs forming the deepest gorge in the world. It offers an invaluable opportunity to directly observe a cross section through the continental crust involved in the Himalayan orogen. The north-south trend of the valley runs almost perpendicular to the dominant regional strike and cross cuts the major tectonic units that comprise the Himalaya including the Lesser Himalayan Sequence, the Greater Himalayan Sequence and the Tethyan Sedimentary Sequence. The valley is easily accessible compared to many other sections across the belt and its history as a popular trekking route ensures services and lodging that are often not available elsewhere. We propose a one-week itinerary across the low metamorphic grade Proterozoic quartzites of the Lesser Himalayan Sequence in the south, through the high-grade, migmatitic metamorphic core of the Greater Himalayan Sequence to the unme...
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