Search results for "feature"

Tectonic beheading of fluvial valleys in the Maestrat grabens (eastern Spain): Insights into slip rates of Pleistocene extensional faults

2013

Abstract Interaction between faulting and landscape evolution in regions of active tectonics allows us to use subtle geomorphological markers for estimating fault slip rates. Geomorphic features of two valleys connected with the bottom of the Alcala de Xivert graben, at the Maestrat graben system (eastern Spain), suggest that they correspond to the lowest segments of ancient valleys whose original heads were located at the axis of the neighbouring Irta range. They were beheaded owing to displacement of the Torreblanca and Irta faults during a period of active extensional faulting in Middle Pleistocene times. These faults produced a negative inversion of the relief, sinking a narrow graben (…

Phylogeny and biogeography of fossil and extant Microtus (Terricola) (Mammalia, Rodentia) of Sicily and the southern Italian peninsula based on curre…

2011

Abstract The fossil record of the Savi vole, Microtus ( Terricola ) savii , is analyzed in terms of morphological and morphometrical variability of the first lower molar, in order to reconstruct phylogenetic relationships between insular and mainland populations and the dispersal events. The present work gives a contribution to better understand the phylogenetic history of this taxon in Sicily and Southern Italy during the interval Middle Pleistocene – Holocene, in an attempt to reconstruct the relationships between insular and continental voles and to clarify some paleobiogeographical aspects. The morphometrical data have been acquired by traditional measurements of the first lower molar a…

Vertical movements in NE Sicily and its offshore: Outcome of tectonic uplift during the last 125 ky

2013

New data in the coastal area between Acquedolci and Patti (northeastern Sicily, Italy) have been collected to calculate vertical tectonic rates in a key sector between the Kabilian-Calabrian and the Sicilian-Maghrebian chain. The comparison among marine geology data (multibeam and seismic reflection profiles) on the continental shelf-slope system and the radiocarbon ages on geomorphological markers collected during a coastal survey, provided new stratigraphic, geomorphological and biological data, contributing to the knowledge of the geological evolution of this sector for the last 125 ky.This coastal area is framed between two main structural features active during the Pleistocene in north…

Middle-Late Pleistocene marine terraces and fault activity in the Sant’Agata di Militello coastal area (north-eastern Sicily)

2012

Abstract The coastal sector of Sant’Agata di Militello (north-eastern Sicily) is characterized by a flight of raised Middle-Upper Pleistocene marine terraces occurring at different heights with respect to present sea level. In particular, the geomorphological survey and the analysis of stereo-pairs of aerial photographs allowed to recognize at least five main orders of well preserved Quaternary surfaces and relative deposits mostly located at the hanging wall and at the footwall of the Pleistocene northwest-dipping Capo d’Orlando normal fault, which controlled the geomorphological evolution of the coastal area. The marine terraces show an overall good morphological continuity and are formed…

Defining the Island Dwarfing Rate of an Extinct Sicilian Elephant Using Ancient DNA

2020

Evolution on islands, and the often extreme phenotypic changes associated with it, has attracted much interest from evolutionary biologists. However, measuring the rate of change of a particular phenotypic trait of extinct animals can be challenging, due to the incompleteness of the fossil record. Here, we use combined molecular and fossil evidence to define the minimum and maximum rate of dwarfing in an extinct Mediterranean dwarf elephant from Puntali Cave (Sicily). Despite the challenges associated with recovering ancient DNA from warm climates, we successfully retrieved a mitogenome from a sample with an estimated age between 147,000 and 50,000 years. Our results suggest that this speci…

Palaeogeographical relationships between Alpine and Jura glaciers during the two last Pleistocene glaciations

1992

Abstract Two main moraine complexes are usually defined in the northwestern Alpine piedmont: the External Moraine Complex (EMC) dated to the penultimate glaciation (“Riss” sensu lato) and the Internal Moraine Complex (IMC) dated to the last glaciation (“Wurm”). Until recently the prevalent concept was that these two complexes had been built by glaciers originating in the central Alpine zone. This paper presents a new palaeogeographical diagram, based on mapping and petrographical studies of these two moraine complexes, and especially on the relationships between Alpine and Jura tills. We reach the following conclusions. 1. (1) The Jura glaciers were independent of the Alpine glaciers during…

1999

The Quaternary karstic site of Sierra de Quibas (Abanilla, Murcia, Spain) has provided a wide faunistic list with 53 species distributed among gastropods, myriapods, amphibians, reptiles, birds and mammals. Especially interesting among the gastropods is Palaeoglandina that became extinct in Europe during the Pliocene. It remains as a relict genus in the Pleistocene of the Iberian Peninsula. Two of the birds, Gypaetus barbatus and Geronticus eremita, and a snake, Elaphe cf. E. sealaris, are scarcely represented in the fossil record. For several birds, it is the first record in the Lower Pleistocene of the Iberian Peninsula. Among the mammals, the presence of the Cercopithecine Macaca sylvanu…

Pleistocene Glaciations in Latvia

2011

Abstract During the Pleistocene the territory of Latvia was repeatedly overridden by Scandinavian ice sheets, at least from the Elsterian onwards. Extent limit of all glaciations was located far outside of Latvia. Due to vigorous erosion by subsequent glaciations the Pleistocene record is incomplete. Radiocarbon, cosmogenic nuclide and radiation exposure dating methods have been mainly used only for age determination of the upper part of the Pleistocene sequence. Decay of the Late Weichselian glaciation in Latvia is marked by five major ice-marginal zones

Pre-3000 Ma thermal history of the Archean Kaap Valley puton, South Africa

1992

The Kaap Valley pluton is one of several early Archean (3200-3500 Ma) tonalitetrondhjemite plutons that surround the Barberton Greenstone belt, southern Africa. Precise dating using single-grain 207 Pb/ 206 Pb evaporation of zircon and 40 Ar/ 39 Ar laser step-heating of hornblende and biotite indicates that, in its interior, the Kaap Valley pluton preserves a memory of its initial intrusion and cooling, which spanned a time from 3225 to 3142 Ma. The pluton also records the effect of a low-temperature thermal event at its margin as seen by a 40 Ar/ 39 Ar biotite age of 3035 Ma, which is perhaps related to hydrothermal activity and gold mineralization in the adjacent Barberton Greenstone belt…

Elements of the Archean thermal history and apparent polar wander of the eastern Kaapvaal Craton, Swaziland, from single grain dating and paleomagnet…

1989

Abstract Single grains of zircon, hornblende, biotite and feldspar have been dated to define the thermal history of the Archean Mbabane Pluton, Swaziland. Coincident207Pb/206Pb zircon and40Ar/39Ar hornblende ages suggest that the pluton underwent rapid cooling to about 450°C at the time of emplacement at ∼ 2690 Ma. Because the Mbabane Pluton is one of a suite of granites which represent the last major Archean intrusive event in the eastern Kaapvaal Craton, this time of emplacement marks the end of cratonization. Much younger biotite and feldspar ages indicate argon loss, perhaps due to several low-temperature events related to dike intrusion at 2000–2300 Ma. From such a thermal history, the…