Search results for "Category"

2001

The main limnological characteristics of the biogenic meromictic Lake La Cruz, a small karstic lake located on a dolomitic substrate, are outlined below. The lake owes its chemical stratification mainly to high concentrations of bicarbonate and calcium in the permanent monimolimnion, located below a depth of 19 m. A massive precipitation of CaCO3 crystals ("whiting"), occurring in the euphotic zone every summer, leads to further sedimentation and redissolution in deep waters with enhanced CO2 concentrations. Other ions, like magnesium, ammonium, reduced iron, silicate, etc. also contribute to the chemically-induced stability of the monimolimnion. The patterns of stratification during two co…

Active moss monitoring allows to identify and track distribution of metal(loid)s emitted from fumaroles on Vulcano Island, Italy

2014

Abstract Volatile metal(loid)s are known to be emitted from volcanoes worldwide. We tested the suitability of active moss monitoring for tracking volatile metal(loid)s released from the fumarolic field on Vulcano Island, Italy, and differentiated fumaroles from other sources of gaseous and particulate trace elements such as sea spray and soil. Metal(loid) accumulation on the mosses per day did depend neither on the state of the exposed moss (dead or living) nor exposure time (3, 6, or 9 weeks). After collection, mosses were digested with either HNO3/H2O2 or deionized water and analyzed by ICP-MS. While for most elements both extraction methods yielded similar concentrations, higher concentr…

Elevation of the last interglacial highstand in Sicily (Italy): A benchmark of coastal tectonics

2006

Well-preserved MIS 5.5 terraces in Sicily are identified primarily by the index fossil Strombus bubonius, and dated by amino acid racemization (AAR), electron spin resonance (ESR), Uranium/Thorium (U/Th) and thermo luminescence (TL) methods. This review of published data and new results for the island of Sicily and neighbouring small islands of Egadi, Ustica and Lampedusa identifies areas of rapid uplift in the east (up to +175 m, elevation above sea level), slower uplift in the north (+29 m), and relative stability in the northwest (+2/+18 m). In contrast, about 250 km of the southern coastline of Sicily does not appear to contain MIS 5.5 outcrops. In eastern Sicily, correlation of MIS 5.5…

Taxonomy and evolution of the Triassic conodont Pseudofurnishius

2013

Pseudofurnishius is a late Anisian (Pelsonian)—early Carnian (Cordevolian) conodont genus of gondolellid stock, characteristic for the Sephardic Province and restricted to the “Southern Tethys” region of the northern margin of Gondwana. Its most commonly found species, Pseudofurnishius murcianus, appears at the base of the Ladinian (Fassanian). The Ladinian material of Spain reveals its ontogeny characterised by initial lateral protrusions from the carina that may develop first mono-platform and later bi-platform units, finally evolving into elaborated multi-denticulated forms. The late Anisian—early Carnian phylogenesis of Pseudofurnishius priscus → P. shagami → P. murcianus is proposed. A…

Presence of cave bears in western Austria before the onset of the Last Glacial Maximum: new radiocarbon dates and palaeoclimatic considerations

2014

Tischoferhohle and Pendling-Barenhohle near Kufstein, Tyrol, are among the only locations where remains of cave bear, Ursus spelaeus-group, were found in the western part of Austria. One sample from each site was radiocarbon-dated four decades ago to ca. 28 14C ka BP. Here we report that attempts to date additional samples from Pendling-Barenhohle have failed due to the lack of collagen, casting doubts on the validity of the original measurement. We also unsuccessfully tried to date flowstone clasts embedded in the bone-bearing sediment to provide maximum constraints on the age of this sediment. Ten cave bear bones from Tischoferhohle showing good collagen preservation were radiocarbon-date…

Palaeoecology of non marine algae and stromatolites: Permian of France and adjacent countries

1999

Abstract Some Permian, continental basins from Algeria, Morocco, France, Italy, Germany and Poland reveal algal remains and stromatolites, mainly during Lower Permian, but also during Middle and Upper Permian. The algae belong to 8 morphogenera and 12 morphospecies. Two species are new. The taxonomic attributions are difficult, even if some species resemble living species. The algae make unorganized masses, or laminated builtups (stromatolites, oncolites, oolites). Algal masses and stromatolites are contained in fluviatile sediments (active or abandoned channels) and lacustrine deposits (playas, ephemeral lakes shorelines, lakes several meters or decameters deep). Considering the sedimentol…

A multi-gene approach reveals a complex evolutionary history in the Cyanistes species group

2011

Quaternary climatic oscillations have been considered decisive in shaping much of the phylogeographic structure around the Mediterranean Basin. Within this paradigm, peripheral islands are usually considered as the endpoints of the colonization processes. Here, we use nuclear and mitochondrial markers to investigate the phylogeography of the blue tit complex (blue tit Cyanistes caeruleus, Canary blue tit C. teneriffae and azure tit C. cyanus), and assess the role of the Canary Islands for the geographic structuring of genetic variation. The Canary blue tit exhibits strong genetic differentiation within the Canary Islands and, in combination with other related continental species, provides a…

A lake fortress, a floating chronology, and an atmospheric anomaly: the surprising results of a radiocarbon wiggle-match from Āraiši, Latvia

2014

Abstract An Iron Age timber settlement which, in view of the defensive structures uncovered, is described as a lake fortress, on an island in Lake Āraiši, north-eastern Latvia, was excavated in 1965–69 and 1975–79 by teams led by Jānis Apals, who distinguished five construction phases. Dendrochronological analysis produced a c. 100-year floating chronology for Norway spruce (Picea abies (L.) Karst.) timbers from the earliest phase. A 14C wiggle-match was undertaken to obtain an absolute date range for the final year of the floating chronology, and thus for the construction of the settlement. Ten blocks of wood from one timber, each comprising 6-11 years and collectively spanning the whole 9…

Lowstand carbonates, highstand sandstones?

2003

The sedimentary facies, sediment dynamics and sequence architecture of modern high-energy shelves in the mid and high latitudes are largely governed by wave abrasion processes. Cool-water carbonates may form there, if the influx and/or net accretion of siliciclastics is kept at a minimum. Little dilution of the carbonate produced in situ is generally promoted by a wide "epicontinental" shelf, subdued topography of the adjacent mainland, the predominance of limestone outcrops, and an arid climate. The aforementioned requirements are rarely met, and thus will automatically lead to the formation of mixed siliciclastic-cool-water carbonates. Such an example is found in the Early to Mid-Miocene …

Timing the Mesolithic-Neolithic Transition in the Iberian Peninsula: The Radiocarbon Dataset

2019

In this paper, we describe the radiocarbon dataset compiled in the context of the project HAR2015-68962 EVOLPAST: Dinamicas evolutivas y patrones de variabilidad cultural de los ultimos cazadores-recolectores y el primer Neolitico en el este peninsular (7000–4500 cal. BC) funded by the Spanish government. The dataset offers the most complete and public radiocarbon dataset focus on the Neolithic Transition in the Iberian Peninsula. Funding statement: The data collection was funded by the Spanish Ministry of Economy, Industry and Competitiveness grant HAR2015-68962-P to Oreto Garcia Puchol & Joan Bernabeu. SPG is supported by Spanish Ministry of Economy, Industry and Competitiveness, Postdoct…