1,720,980 research outputs found
Piacenzian–Gelasian non-marine ostracods from the Dunarobba Fossil Forest (Tiberino Basin, Umbria, central Italy)
No full textThe taxonomy of some non-marine ostracod assemblages from the Dunarobba Fossil Forest area (south Tiberino Basin, Umbria, Italy) is discussed, adding to the scientific understanding of Piacenzian–Gelasian non-marine ostracods in central Italy and providing a palaeoenvironmental reconstruction of the shallow coastal lacustrine environments of the Palaeolake Tiberino. The ostracod assemblages include Darwinula stevensoni, Vestalenula cylindrica, Candona (Candona) improvisa, Candona (Neglecandona) neglecta, Candona (Neglecandona) angulata, Candona (Neglecandona) paludinica, Caspiocypris basilicii, Caspiocypris tiberina, Candonopsis kingsleii, Cyclocypris ovum, Ilyocypris bradyi, Ilyocypris decipiens, Cypris mandelstami, Zonocypris membranae quadricella, Potamocypris fulva, Cyprideis crotonensis, Cyprideis rectangularis and two new species: Hemicypris lomastroi sp. nov. and Paralimnocythere turgida sp. nov. In addition to widespread European species, the ostracod assemblages contain some rare species that were previously known from the Pliocene Paludinian Beds of Serbia. A cluster analysis applied to the ostracod frequency matrix has lead to the identification of four separate assemblages that can be attributed to several ecological niches, including emerged hydrosols, ephemeral coastal pools and a littoral lacustrine margin, which suggest a complex coastal environment
Seismic site characterisation of Red Soil and soil-building resonance effects in L’Aquila downtown (Central Italy)
No full textWe present a fine-scale shallow geological setting and its possible influence on the seismic building behaviour of L’Aquila downtown which suffered many casualties and building damage caused by the 6 April 2009, Mw 6.1 earthquake. This study draws mainly on the integration of 666 borehole logs and 274 microtremor recordings interpolated with GIS-based techniques. The shallow geology of L’Aquila downtown is characterised by Middle Pleistocene calcareous L’Aquila breccias. Their top surface consists of a weathered epikarst zone that is mantled by Red Soil (reddish colluviated Alfisols) formed during the late Pleistocene. The areal distribution and thickness of Red Soil are causative of the medium microtremor frequency (3–13 Hz). The map of cross-correlation between the medium frequencies, estimated through the empirical Eurocode 8 equation, shows buildings with possible seismic coupling due to the shallow geology setting and the fundamental building period. This technique is further supported by the areal distribution of seismic building damages caused by the 2009 and 1703 L’Aquila earthquakes. This approach, carried out with a large geological and geophysical dataset, is useful in defining seismic site effects and may be effective in mitigating the seismic risk of cities with notable historical heritage in Central Italy, such as the L’Aquila downtown area
Taxonomic harmonization of Neogene and Quaternary candonid genera (Crustacea, Ostracoda) of the Paratethys
No full textDuring the Cenozoic, the constant northward movement of the African plate led to the division of the Tethys Ocean into two: the Palaeomediterranean and the Paratethyan branches. The latter was represented by a huge epicontinental sea and brackish to freshwater lakes that extended across central Europe and western Asia. Neogene and Quaternary ostracods from the Paratethys originated through major adaptive radiations, which gave rise to endemic brackish taxa. Unfortunately, much confusion surrounds their taxonomy, due to the quality of descriptions and images in the original literature and the incompleteness of the type material, making necessary a taxonomic revision. In this paper, we propose a systematic revision of several Paratethyan endemic candonid genera based on the analysis of the type material, new material collected from the type localities, and new fossil material from the Ponto-Caspian area. The study focuses on the description of the valve morphology and particularly on the geometric morphometric analysis of the valve outline. Thirty-three genera were taken into account of which four (Advenocypris, Candoniella, Graviacypris, Telekia) were considered to be junior synonyms of Typhlocypris, Pseudocandona or Candona. Moesiella is considered a nomen nudum. In the case of Caspiollina, Dacicandona, Liventalina and Turkmenella the scarcity of material and/or the poor descriptions reported in the literature prevented us from performing a full revision. The monospecific genus Thaminocypris possibly includes a teratological form. The remaining 23 genera were merged into nine valid, endemic, genera (Bakunella, Camptocypria, Caspiocypris, Hastacandona, Lineocypris, Pontoniella, Propontoniella, Typhlocyprella and Zalanyiella). Emended diagnoses and descriptions are proposed for these genera and a new species, Bakunella anae sp. nov., is described. This study considerably reduces the taxonomic uncertainty within the Paratethyan candonids, providing new data for the evaluation of the palaeobiodiversity of the Paratethyan domain. Finally, the palaeobiogeography of Paratethyan candonids during the Neogene and Quaternary is also discussed. http://zoobank.org/urn:lsid:zoobank.org:pub:EB9EC2D4-AFD2-428E-9958-C97F36ED7FF2
Geological map of the Plio-Quaternary deposits of the Paganica - San Demetrio - Castelnuovo Basin (central Italy) (scale 1:25000)
No full textNew data on the lower Pleistocene (Gelasian) lignite beds of Castel San Pietro (Rieti, Central Italy)
No full textA multiproxy study of the lignite-bearing lacustrine sequence cropping out at Castel San Pietro (CSP) (Rieti, central Italy) provides new insights on the paleoenvironmental evolution of an extensional basin, located on the Tyrrhenian side of the Apennine range. The CSP fossiliferous levels reflect deposition in a stable lacustrine environment. Mammal remains collected from this locality during the past centuries include Stephanorhinus etruscus, Anancus arvernensis and the beaver Castor fiber. The co-existence of the Etruscan rhinoceros and the mastodont suggests a middle Villafranchian age (Montopoli or Coste San Giacomo Faunal Unit) for the lignite beds of CSP. New paleoflora findings are in agreement with an attribution to the Piacenzian or Gelasian age for these deposits whilst the presence of the ostracod Qinghaicypris cf. Q. riojensis suggests a time interval from Zanclean to Gelasian (between ~4.5 and ~1.8 Ma). Accordingly, the lignite beds of CSP most likely were deposited during the Gelasian (from ca. 2.5 to 1.8 Ma; from Montopoli to Coste San Giacomo FUs or possibly to Olivola FU) in forested area and warm and humid conditions
What was the role of faults in the evolution of the Montereale basin (Central Apennine)? Considerations and non-exhaustive answers
Full text linkNew insights on bedrock morphology and local seismic amplification of the Castelnuovo village (L'Aquila Basin, Central Italy)
No full textThe Castelnuovo village is placed on a small NW-SE trending ridge, approximately 60 m higher than the valley floor, occupying a portion of the larger continental L'Aquila Basin (Central Italy). During the April 6, 2009 L'Aquila earthquake (Mw 6.3), the village suffered heavy damage. Several studies investigated the local seismic amplification of the Castelnuovo area employing geotechnical, geophysical, and geological surveys, together with 1D, 2D and 3D numerical models. However, all these studies relied on shallow geotechnical and geophysical surveys, which do not reach the engineering bedrock and do not constrain the presence of an impedance contrast at depth. To date, no detailed study has been carried out to assess the depth of the engineering bedrock. In this work, we fill this gap by executing two deep boreholes reaching the engineering bedrock, tied with an extensive campaign of microtremor measurements all over the Castelnuovo ridge and the surrounding plain. The interpretation of such new data, together with analytical, numerical, and geostatistical techniques, demonstrates that local seismic amplification is linked to a strong impedance contrast at more than 200-m depth beneath the Castelnuovo village associated with the lithological transition between clayey silts and breccias. Such results differ from those provided by previous studies, where such impedance contrast was considered shallower, and represent a milestone for assessing the local seismic hazard of the area
Seismic characterization of Pizzoli (Central Italy) to estimate site effects induced by near-fault earthquakes
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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