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New facies interpretation of the Messinian evaporites in the Mediterranean
No full textIntroductionThe study of the Messinian salinity crisis (MSC) in the Mediterranean has generated a controversy with a long-term discussion on many aspects. One of the problem faced by the scientists is that the interpretation of evaporite sediments can be very complicated. Evaporite sediments are among the most elusive for facies reconstruction and correlation and most data in the literature were not correctly placed in a reliable stratigraphic framework. Some examples of these difficulties are the following: a) deposits traditionally included in the Lower Evaporites are actually clastic sediments that, as we have shown, derive from the dismantlement of autochthonous Lower Evaporites (Manzi et al., 2005; Roveri et al., 2006);b) many of the Lower Evaporites outcrops in Italy are actually large-scale blocks emplaced by extensive mass-waste movements (Roveri et al., 2003; Roveri et al., 2006); some of these chaotic complexes were interpreted as collapse deposits due to halite dissolution (Caruso and Rouchy, 2006);c) some Lower Evaporites outcrops were commonly considered Upper Evaporites and vice-versa;d) laminated clastic sulphate sediments were commonly mistaken for primary cumulate deposits and vice-versa;e) the significance of halite deposition, which actually bears the only unequivocal sign of exposure found within the Messinian evaporites, has been overlooked;f) the Calcare di Base carbonates show commonly evidence of resedimentation;g) the Calcare di Base is never found at the base of the Lower Evaporites primary in situ selenites;h) lateral transitions between carbonate, gypsum or halite primary evaporites cannot be directly observed and must be considered speculation;For these reasons we devoted our efforts to provide a detailed stratigraphic and facies analyses of all the Messinian evaporites and criteria for distinguishing the Lower from the Upper Evaporites. The main aim was to discuss new possible stratigraphic markers to correlate the elusive evaporite sediments across the Mediterranean during the MSC and to correctly place the Messinian units into a reliable stratigraphic framework.Finally, as the peculiar and restricted setting of evaporite deposition makes the use of geochemical data problematic, we need to integrate the geochemical data in a detailed stratigraphic and facies framework. This because many of the available isotope data are scattered and commonly obtained from sections whose stratigraphy is not well constrained in the regional framework. An extensive study of the literature showed that the majority of the geochemical data were provided without a reliable record even for the local stratigraphy.This presentation illustrates our studies on a new evaporite facies interpretation that may be useful for large-scale correlations. The effort is to provide a new reliable facies, isotope and stratigraphic framework for the understanding of the Salinity Crisis in the Mediterranean
Match analysis e sport di squadra. Controllo delle relazioni tra qualità fisiche di giovani calciatori U14 valutate tramite test da campo e la prestazione fisica espressa in gara.
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Physiological determinant of yo-yo intermittent recovery test in young basketball players
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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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