Search results for "Continent"
showing 10 items of 598 documents
Vestiges of the Mesoproterozoic Events in the Neoproterozoic Mozambique Belt: the East African Perspective in the Rodinia Puzzle
2003
Abstract Most of the geological and palaeogeographical models consider the Neoproterozoic supercontinent Gondwana (∼650-550 Ma) as the direct offspring of the disintegrated Mesoproterozoic supercontinent Rodinia (∼1300-750 Ma). One of the main classical sutures along which the dispersing Rodinia fragments were fused into a new supercontinent (Godwana) is identified as the Mozambique belt of East Africa. The calc-alkaline magmatism (∼1200-950 Ma) in northern Mozambique, southern Malawi and southern Tanzania is regarded as the sole evidence for fragmentation of Rodinia, which is traced within this Neoproterozoic orogenic belt. There are no unequivocal Mesoproterozoic (Kibaran) sediments in th…
Ca. 750–1100 Ma magmatic events and Grenville-age deformation in Sri Lanka: relevance for Rodinia supercontinent formation and dispersal, and Gondwan…
2003
Abstract Large volumes of ∼880–1100 Ma calc-alkaline granitoid rocks in the Wanni and Vijayan crustal provinces of Sri Lanka make it likely that these domains were produced in active margin settings, probably Grenville-age magmatic arcs. We report new single zircon evaporation ages and Nd isotopic systematics for dioritic to granodioritic gneisses of the Kadugannawa Complex of central Sri Lanka which record a period of magmatic arc activity between 1006 and 881 Ma and show this complex to be part of the Wanni domain. Both provinces were probably generated in arc-related settings at the outer margin of Rodinia, but this cannot be ultimately proven on the basis of the currently available data…
The oldest rocks of Greece: first evidence for a Precambrian terrane within the Pelagonian Zone
2005
The Pelagonian Zone in Greece represents the westernmost belt of the Hellenide hinterland (Internal Hellenides). Previous geochronological studies of basement rocks from the Pelagonian Zone have systematically yielded Permo-Carboniferous ages. In this study we demonstrate, for the first time, the existence of a Precambrian crustal unit within the crystalline basement of the Pelagonian Zone. The U–Pb single-zircon and SHRIMP ages of these orthogneisses vary from 699 ± 7 Ma to 713 ± 18 Ma, which identify them as the oldest rocks in Greece. These Late Proterozoic rocks, which today occupy an area of c. 20 × 100 km, are significantly different from the neighbouring rocks of the Pelagonian Zone.…
Pan-African granulite formation in the Kabye Massif of northern Togo (West Africa): Pb−Pb zircon ages
2000
Metamorphic zircons from seven granulite facies orthogneisses of tonalitic composition (ender- bites), collected from four different nappes of the Kabye Massif in the Dahomeyide belt of northern Togo, were dated by the Pb-Pb evaporation method. They yielded consistent Neoproterozoic ages with a mean of 612.5 0.8 Ma, interpreted to reflect the peak of regional granulite facies metamorphism following Pan-African continental collision between the West African and Benin-Nigerian plates. These results sup- port previous ages obtained by various chronometers on high-grade rocks from the same suture zone and from surrounding units in Togo, Benin and Ghana. They are also similar to zircon ages fr…
Quantifying the contribution of nitrification and denitrification to the nitrous oxide flux using 15N tracers.
2006
8 pages; International audience; Microbial transformations of nitrification and denitrification are the main sources of nitrous oxide (N2O) from soils. Relative contributions of both processes to N2O emissions were estimated on an agricultural soil using 15N isotope tracers (15NH4+ or 15NO3-), for a 10-day batch experiment. Under unsaturated and saturated conditions, both processes were significantly involved in N2O production. Under unsaturated conditions, 60% of N-N2O came from nitrification, while denitrification contributed around 85-90% under saturated conditions. Estimated nitrification rates were not significantly different whatever the soil moisture content, whereas the proportion o…
Geoacoustic Inversion with Drifting Buoys: Enverse 1997–98 Experiments (Marettimo Is.)
2000
Acoustic buoys were developed to allow the rapid determination of range-dependent bottom properties in a shallow water environment from the inversion of propagation measurements. The main features of the buoys are the large dynamic range, digital signal conditioning unit, global positioning system receiver and reliable radio data link. The buoys drift away from a broadband source receiving its pings at known positions. Single hydrophone, matched waveform, inversion techniques are applied to the received signals to invert for geoacoustic parameters. Eight prototypes were tested over the southern continental shelf off the island of Marettimo (Sicily) during the EnVerse 97 sea trials. Calibrat…
Reflections on the 25th Congress of the European Society for Pediatric Urology Part 1
2014
The 25th annual meeting of the European Society for Pediatric Urology (ESPU) took place in Innsbruck, Austria from the 7th to 10th of May 2014. The Specialty Chief Editor and nine Associate editors of Frontiers in Pediatrics, Pediatric Urology were in attendance. Each was asked to select the two presentations that they considered most significant. Here, we highlight some of the papers that we found of particular interest and that may impact our practices. This report reflects personal preferences of the authors and does not pretend to be comprehensive or to rank the quality of the presentations. We are aware that some important presentations may not be included. Our selections are presented…
Quality of Life and Health in Patients with Urinary Diversion: A Comparison of Incontinent versus Continent Urinary Diversion
1997
Objective: To compare the quality of life and health in patients with incontinent and continent urinary diversions, in correlation with the initial diagnosis, diversion-related symptoms, psychological status and employment status. Materials and Methods: 81 patients (64% male and 36% female) with a mean age of 55 years (18-65 years) were included in this retrospective study. A total of 27 had an incontinent urinary diversion (group A) and 54 a continent diversion (group B). The initial diagnosis was malignant tumor in 75% (n = 61) and nontumor disease in 25% (n = 20). A structured interview and psychometric instrument assessment of the quality of life as well as somatic and psychological sym…
Geo-hazards of the San Vito peninsula offshore (southwestern Tyrrhenian Sea)
2021
Geomorphological Tools for Mapping Natural Hazards.-- 12 pages, 7 figures, supplemental material https://doi.org/10.1080/17445647.2020.1866703.-- Software: The geomorphological main map and the Figures in the text were compiled using GLOBAL MAPPER, Surfer and Quantum-G GIS Software and redesigned to print with Adobe Illustrator
Síntesis de los estudios sobre moluscos continentales neógenos del sector septentrional de la Depresión de Teruel: período 1775-1998
2006
Se recopila y analiza la información que se considera más relevante y se encuentra contenida en los estudios realizados sobre el registro fósil de los moluscos neógenos del sector septentrional de la Depresión de Teruel en el período comprendido entre los años 1775 y 1998. Se contabilizan, por una parte, el número total de taxones diferentes mencionados en cada trabajo y, por otra, sólo el número de citas efectuadas a nivel de especie en cada uno de ellos. Estas últimas se organizan en tres categorías que reciben el nombre de citas nuevas, especies nuevas y citas repetidas. Se propone, a partir de la información contenida en cada trabajo, el número de taxones contemplados, y la tipología de…