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A multidisciplinary approach to study confined marine basins: the holobenthic and merobenthic assemblages in the Mar Piccolo of Taranto (Ionian Sea, Mediterranean)
No full textBenthic foraminifera and ostracods, and resting stages (cysts) of plankton were analysed from surface sediment samples collected at 20 stations in the Mar Piccolo of Taranto (Ionian Sea, Mediterranean), with the aim to advance our knowledge on the biodiversity and ecological features of confined marine areas and to upgrade the autoecology of the species, and to have a more detailed and complete information to be applied as the baseline in future studies on environmental quality. In order to better assess the spatial distribution of the holobenthic and merobenthic species, we conceived a simple method of spatial analysis, based on all the identified taxa of foraminifera, ostracods and plankton cysts. Five groups were established on the basis of the number of sites per sub-basin where each taxon was registered, and this allowed us to recognise the preferential patterns of distribution for 150 species. The good correspondence between the results of the spatial analysis and those obtained from the analysis of the communities and the uni- and multivariate statistics showed a clear difference between the two sub-basins of the Mar Piccolo of Taranto
Geoarcheological evidences of changes in the coastline progradation rate of the Versilia coastal plain between Camaiore and Viareggio (Tuscany, Italy): possible relationships with Late Holocene high-frequency transgressive regressive cycles
Get PDFThe Late Holocene progradation of the Versilia coastal-plain, between Camaiore and Viareggio (Tuscany, Italy), was investigated on the basis of geomorphological, stratigraphical, and archaeological data. Five geomorphological units, corresponding to the Camaiore alluvial fan, beach-dune ridges, interdune marshes, a back dune marsh (Giardo and related Massaciuccoli lake area), and the present day beach, were identified.
Archaeological data provide some chronological constraints on the timing of Late Holocene coastal progradation. About 3000 yrs ago, the coastline was located about 2,5 km landward in respect to its present-day position, in the proximity of the Migliarina beach dune, behind which a marsh area developed. This marsh extended from the Giardo to the present-day Massaciuccoli Lake. The connection between Giardo and Massaciuccoli area allows us to reconsider the role of Acquarella site in becoming an important centre in commercial
communication among sea, coast, and inland areas. Around the 12th century the coastline was located in proximity of the dune alignments where Motrone Fort and the Castello Vecchio di Viareggio were built testifying a progradation of about 1,3 km. During the next four centuries the coastline continued its seaward shifting for 500 m more and was located in proximity of the Matilde Tower.
From the 16th to the present time the progradation of the coastline has been proceeded by of about 0,7 km. These data indicate changes in the progradation rate during that the time and in particular an increase since the 16th century. An irregular progradation rate agrees with stratigraphic and facies analysis based on surface and subsurface data (wells and excavations) that allowed us to define a
preliminary framework of the last phases of coastline progradation. The identification of four high-frequency small-scale transgressive regressive
cycles (parasequences) within the succession recording the Late Holocene phase of progradation points to evidence that the progradation rate of the coastline was subject to cyclic fluctuations
The Miocene successions of the Fiora Hills: considerations about the development of the minor basins of Southern Tuscany
No full textThe Miocene sequences of Southern Tuscany represent the first post-nappe sedimentary record of the Northern Apennines, and are linked with the opening of the Tyrrhenian Sea. The sequences are located in several basins, characterizing the hinterland of the orogen. They are settled on a stack that is composed of deformed tectonic units and are capped by Plio-Pleistocene deposits. The respective basins have been strongly controlled by tectonics, which have remarkably forced the sedimentation. The Fiora Hills represent the southernmost area of Tuscany, where there are some minor but significant examples of these basins. In particular, they are the Fiora and the Tafone basins, the infillings of which are characterized by Miocene successions subdivided into several depositional units separated by unconformity or correlative conformity surfaces. This study deals with the stratigraphic features of such Miocene basinal infillings, with the aim being to define the depositional architecture and the tectonic-sedimentation interplays. Moreover, the collected data also enables there to be a discussion of some of the aspects of the basins' structuring that are linked with the Miocene evolution of the hinterland of the Northern Apennines. The entire Miocene succession of the Fiora Hills spans from the Langhian up to the late Messinian, with there being minor differences between the Fiora-Tafone basins and with the nearby Albegna Basin. In general, we recognize: the basal Ponsano P Unit (middle Miocene), which is referable to coastal-shallow marine environment; the Lignitiferous T Unit (late Tortonian-early Messinian), which is referable to fan-delta and lacustrine systems; the Acquabona-Spicchiaiola M1 Unit (early Messinian), which is referable to lagoonal fan-deltaic environment; the Castelnuovo M2 Unit (early Messinian), which is referable to shallow marine environment; and the "Lago-Mare" M3 Unit (late Messinian), which is referable to fan-deltaic lacustrine systems. The Miocene succession is overlaid by Plio-Pleistocene marine to continental succession. The Miocene basins have settled on deformed Ligurian allochthonous units, which are markedly structured in tectonic depressions and highs and coherently so with the "crustal lateral segmentation" model. The development of the Miocene sedimentation in this sector of the chain appears to be strictly connected to the tectonic evolution of the Tyrrhenian Sea rifting. The middle Miocene deposits may in fact be related to the first syn-rift shallow-marine basins, marking the beginning of the post-nappe phase. During late Tortonian-early Messinian, important lacustrine-fan-delta systems dominated in the basins and represented the development of the middle Miocene stages. They evolved during the early Messinian in lagoonal fandeltaic systems and then in shallow-marine systems. The transition to the upper Messinian deposits is marked by a significant unconformity, which is marked locally by angularity, thus noting an intramessinian deformative episode. This characterizes the lacustrine fan-deltaic systems that are linked to the Messinian salinity crisis for the paleo-Mediterranean Sea. The stratigraphic differences between the Fiora Hills' basins are therefore linked to the somewhat different basinal sedimentary evolution, which is connected to the development of morphological/tectonic ridge
Preliminary stratigraphycal investigations on the Miocene Successions of the Porto Torres Basin (Northern Sardinia, Italy)
No full textThe following is a brief report on a preliminary micropalaeontological research carried out on the Miocene succession of the Porto Torres Basin (Northwestern Sardinia, Italy). Planktonic foraminifers and ostracods from 12 samples collected in the northeastern side of the basin within marls and marly chaotic beds of unknown – dubitatively Langhian – age have been analyzed. From a biostratigraphic viewpoint assemblages unquestionable allowed us to refer the investigated succession to the upper Burdigalian. The ostracod palaeoecological analysis indicates a depositional setting referable to the intermediate part of the outer neritic zone. In addition, since from a general ostracod standpoint the Mediterranean lower Miocene is relatively unexplored, the new biostratigraphic data obtained from this study are discussed
The late Messinian “Lago-Mare” event and the Zanclean Reflooding in the Mediterranean Sea: New insights from the Cuevas del Almanzora section (Vera Basin, South-Eastern Spain)
No full textThe return to normal marine conditions in the Mediterranean Sea after the end of the Messinian Salinity Crisis (MSC), that led to the deposition of thick evaporitic succession followed by settlement of brackish to freshwater conditions of the “Lago-Mare”, is still subject to extensive debate between two opposite scenarios. One scenario implies an abrupt reflooding through the Gibraltar gateway of the Mediterranean Sea previously disconnected from the world ocean and partly desiccated. The second scenario postulates that the Mediterranean Sea kept a high-water level throughout the Messinian Salinity Crisis and was connected continuously to the Atlantic Ocean and to the Paratethys. The stratigraphic record of the classical Cuevas del Almanzora section (Vera Basin) is of a crucial importance as the Vera Basin is located on the eastern margin of the Alboran Sea close to the Gibraltar gateway where Atlantic waters reflooded the Mediterranean Sea after the MSC. The present new study completes previous investigations (Pierre et al., 2006) and is mostly focused on detailed sedimentological observations, analysis of ostracod and foraminifer assemblages and on stable isotopes study of three species of planktonic foraminifers (Globigerina bulloides, Globigerinoides obliquus s.l. and Sphaeroidinellopsis spp.) from the lower Pliocene deposits. Biostratigraphical correlations with the reference deep-sea section from ODP Site 975 (Balearic Basin) and the onshore succession of Eraclea Minoa (Sicily) provide an accurate chronostratigraphy and paleoclimatic reconstruction during the Zanclean. During the late Messinian, the Vera Basin was characterized by very unstable lacustrine to brackish environments with significant water depth variations and the deposits display evidences of subaerial exposure. The ostracod content is dominated by Loxocorniculina djafarovi and Cyprideis gr. agrigentina associated to reworked planktonic foraminifera from older sediments. The Messinian/Zanclean contact is well marked by a clear erosional surface that grades laterally into a megabreccia with reworked gypsum blocks and to the large incision of the Palomares canyon in the offshore domain. The marine reflooding occurred abruptly with a sea level rise by more than 250 m, an important value for a marginal basin. In this western part of the Mediterranean Sea, the marine invasion began with the onset of the lowermost biozone MPl 1 at the base of the Zanclean. The fluctuations of the planktonic foraminifer assemblages and of their stable isotopes allowed to identify five lithological cycles forced by Milankovitch’ precession periodicity, as well as paleoclimatic variations through the lower part of the Zanclean. Thus, these new data allow us to reaffirm that the Messinian/Zanclean boundary corresponds to a major change, characterized by an “instantaneous” restoration of marine conditions at the onset of the Pliocene, related to the abrupt re-flooding of the Mediterranean Sea from the Atlantic Ocean
Exploring the underwater life in transitional environments: Benthic foraminifera, ostracods, and dinoflagellate cysts – Biotic trends and EcoQS assessment in the Mar Piccolo of Taranto (Ionian sea, southern Italy)
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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