Search results for "CLASSIFICATION"
showing 10 items of 29475 documents
Volcanic products of Lipari (Aeolian islands, Italy): Multivariate analysis of petrographic and radiometric data
2010
Abstract A petrographic and radiometric study, along with statistical multivariate analysis of volcanic products of the island of Lipari (Aeolian islands, Italy) was carried out. The volcanological history of Lipari was reconstructed defining two stages (pre- and post-erosive stages) further on subdivided in four volcanic phases, each of which characterized by products with a particular chemical composition and separated by stratigraphic unconformities. The correlations between petrographic features, determined by X-ray fluorescence, and volcanological history of the island highlight a gradual differentiation with younger rocks showing a more acid chemical composition than the older ones. R…
Mediterranean Tertiary lamproites derived from multiple source components in postcollisional geodynamics
2008
Abstract In the Mediterranean area, lamproitic provinces in Spain, Italy, Serbia and Macedonia have uniform geological, geochemical and petrographic characteristics. Mediterranean lamproites are SiO2-rich lamproites, characterized by relatively low CaO, Al2O3 and Na2O, and high K2O/Al2O3 and Mg-number. They are enriched in LILE relative to HFSE and in Pb, and show depletion in Ti, Nb and Ta. Mediterranean lamproites show huge regional variation of Sr, Nd and 207Pb/204Pb isotopic values, with 87Sr/86Sr range of 0.707–0.722, eNd range from −13 to −3, and 207Pb/204Pb range of 15.62–15.79. Lamproitic rocks are derived from melts with three components involved in their origin, characterized by c…
Orogenic vs anorogenic lamproites in a single volcanicprovince: Mediterranean-type lamproites from Turkey
2008
Lamproites are mantle-derived ultrapotassic volcanic rocks, derived from phlogopite-bearing harzburgitic source. The origin of the metasomatism which enriched their mantle source is either an old event with a metasomatic component derived from the convecting mantle, or is a more recent introduction of an already aged metasomatic component. Together with different trace element signatures, this view serves for a general distinction between anorogenic and orogenic lamproites worldwide. In Turkey, lamproitic volcanism resulted from interplay of subduction/collisional and postcollisional/extensional regime since Miocene until Pliocene, in the Western Anatolia-Aegean and Kirka-Afyon-Isparta regi…
Mesoscale eddies, surface circulation and the scale of habitat selection by immature loggerhead sea turtles
2007
17 pages, 8 figures, 6 tables
A new Lagomorph from the late Miocene of Chad (central Africa)
2007
A new species of the genus Serengetilagus, here named S. tchadensis n. sp., is described from Toros Menalla deposits, Late Miocene of Djurab Erg (North Chad, central Africa). It shows primitive features, such as a simple archaeolagine-type p3, with only two main external folds, and upper cheek teeth strongly widened with wear. Its size and skeletal features resemble S. praecapensis from the Middle Pliocene of Laetoli (Tanzania). They differ in several cranial and dental features (choanae width, zygoma, orbits, basicranial-basifacial angle, lack of hypoflexus in P2, short and asymmetric hypoflexus in P3-M2, lack of lingual folds in p3, etc). Individual variations in S. tchadensis n. sp. appr…
Tortella bambergeri (Pottiaceae) in the Iberian Peninsula, with an updated key to Iberian Tortella
2009
Tortella bambergeri (Schimp.) Broth. is reported for the first time from northern and central-eastern Spain in the Iberian Peninsula. Diagnostic characters and differentiation from other closely related Iberian Tortella taxa are discussed. Furthermore, a map of the currently known distribution of T. bambergeri in Spain, illustrations of the species and an updated key to Iberian Tortella are provided.
First breeding evidence of marbled duck (Marmaronetta angustirostris) in Libya.
2014
4 pages; International audience; The first evidence of breeding of Marbled Duck (Marmaronetta angustirostris) in Libya, North Africa, is reported. In June 2012, at Mallaha wetland, in Tripoli, Libya, two dead ducklings were found that were later genetically identified as Marbled Duck. This breeding evidence suggests that this and other duck species may breed elsewhere in Libya. Better knowledge on Libyan, and more generally on north African, waterbirds is needed to document the population size and the status of these species. Such information will be important to secure the future of threatened species, such as the Marbled Duck.
Dynamics of Ostracoda (Crustacea) assemblages in a Mediterranean pond system (Racó de l'Olla, Albufera Nat. Park) with focus on the exotic speciesCan…
2013
Coastal pond systems can account for a rich aquatic faunal diversity and complex functioning due to interplay between freshwater wetlands and marine influences. Within the large Albufera wetland Natural Park, Raco de l'Olla is constituted by a set of permanent and temporary ponds with strict protection level for migrating bird conservation. Its terrestrial faunal diversity and dynamics has been partially characterized in previous studies, but nothing was known about its ostracod communities. Benthic samples collected monthly for 1 year in 11 points through the pond system, together with limnological information, allowed establishing a sound knowledge on its ostracod community and population…
Cohort-Dependent Sex Ratio Biases in the American Crocodiles (Crocodylus acutus)of the Tempisque Basin
2015
A male-biased sex ratio of 3:1 has been reported for a population of American crocodiles (Crocodylus acutus) in the Tempisque River Basin, Guanacaste, Costa Rica. If confirmed, this would constitute one of the largest male-biased sex ratios reported for any population of a member of the genus Crocodylus. Here, we examine the aforementioned population of C. acutus and report on sex ratios of hatchling, juvenile, and adult age classes within a sample of 474 crocodiles captured in the Tempisque Basin between May 2012 and June 2014. Hatchling sex ratio is exceptionally male biased (3.5:1), an imbalance that is maintained in juveniles but is reduced in adults (1.5:1). Mark–recapture data documen…
The Status of Romanogobio uranoscopus (Agassiz, 1828) Species, in Maramureş Mountains Nature Park (Romania)
2017
Abstract The condition of aquatic habitats typically occupied by Romanogobio uranoscopus within the Maramureş Mountains Natural Park fluctuates, in the best cases, between reduced to average. Good or excellent conservation status is now absent for populations of this species in the researched area. The identified human impact types (poaching, minor riverbeds morphodynamic changes, solid and liquid natural flow changes, destruction of the riparian vegetation and bush vegetation, habitat fragmentation/isolation of population, organic and mining pollution and displaced fish that are washed away during the periodic flooding in the lotic sectors uniformized by humans) are contributing to the dim…