The stress configuration and tectonic analysis of the Pan – African orogeny is drawn from the Igarra schist belt, southwestern Nigeria. The analysis of conjugate shear fractures of the schist belt indicates that two distinct compressive events (NE – SW and E – W) occurred in this Pan – African mobile zone. The palaeostress systems reveal a clockwise rotation of compressional axis from D1 (NE – ...

It is generally accepted that continental subduction and crustal exhumation play an important role in the evolution of many orogenic belts. A variety of geological evidence suggests that continental crust is occasionally subducted to depths of tens to perhaps 150 km (e.g. Chopin, 1984; Dewey et al., 1993; Matte et al., 1997). Recently, a series of simulations (Chemenda, 1993; Chemenda et al., 1...

Uranium-lead data indicate that the high-pressure granulitic and charnockitic nuclei within the medium-grade metamorphic complex of the Peruvian coastal area must be related to an orogenic event 2 x 10(9) years ago. As in western Africa and Brazil, this old granulitic basement is reworked by Late Precambrian orogeny. Its presence along the Peru-Chile Trench must be taken into account in interpr...

The Chazy, Black River and Trenton Groups are a well studied sequence of fossiliferous limestones, dolostones and sandstones in the Champlain Valley of New York, Vermont and southern Quebec. These rocks record shallow water cyclic sedimentation in the foreland basin of Laurentia prior to and during the initial stages of the Taconic Orogeny. This field trip reviews the stratigraphy of these unit...

The Aegean Sea area is thought to be an actively extending back-arc region, north of the present day Hellenic volcanic arc and north-dipping subduction zone in Eastern Mediterranean. shows extensive normal faulting, ductile ‘extensional’ shear zones extensional S-C fabrics throughout islands that have previously been related regional extension associated with slab rollback on Subduction Zone. I...

U-Pb analyses of zircon from ten samples of augen gneisses, eight mafic and intermediate metaigneous rocks and six metasediments from some tectonic domains along the Calabria-Peloritani Terrane (Southern Italy) contribute to knowledge of peri-Gondwanan evolution from Late-Proterozoic to Paleozoic times. All samples were equilibrated under amphibolite to granulite facies metamorphism during the ...

Much of the immense present day biological diversity of Neotropical rainforests originated from the Miocene onwards, a period of geological and ecological upheaval in South America. We assess the impact of the Andean orogeny, drainage of Lake Pebas and closure of the Panama isthmus on two clades of tropical trees (Cremastosperma, ca 31 spp.; and Mosannona, ca 14 spp.; both Annonaceae). Phylogen...