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 Influence of Competition on some Structural Features Persian Oak (Quercus brantii Lindl var.persica) Trees in Zagros Forest (Case study:Hashtad- Pahlu,Lorestan)

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...

There has been controversy over the number and timing of orogenies in the Precambrian Moine block in the Scottish Caledonides since the earliest radiometric dating in the 1960s. This work challenges a recent hypothesis, that this sector of the Laurentian margin was subjected to continuous crustal extension between .900 and 470 Ma. U–Pb dating (thermal ionization mass spectrometry) of titanite f...

The Andes are known to have influenced speciation patterns in many taxa, yet whether species diversification occurred simultaneously with their uplift or only after uplift was complete remains unknown. We examined both the phylogenetic pattern and dates of branching in Adelomyia hummingbirds in relation to Andean uplift to determine whether diversification coincides with the chronological phase...

Abstract The foraminiferal contents of the lower–middle Miocene succession exposed in three sections north Nur Abad on northwestern side High Zagros Thrust Belt were studied. Assemblages larger foraminifera from these can be referred to Zone SBZ 25 (and Miogypsina globulus and intermedia subzones), which correlates with Burdigalian Stage. For first time, planktonic documented area document Lang...