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Hiatuses in semi-enclosed basins can be caused by either eustatic falls or local tectonic uplifts. The Ciscaucasian basin is located in the south of European Russia. In the Neogene, it belonged to the Eastern Paratethys domain. On the basis of available stratigraphic data, four major hiatuses are traced in this basin as erosional surfaces or lengthy sedimentation breaks, namely the Tarkhanian, Middle/Upper Sarmatian, Sarmatian/Maeotian, and Kimmerian hiatuses. They are documented in most of the areas of the study basin. The three earlier hiatuses mark short-term and nearly isochronous, basinwide sedimentation breaks, whereas the latter hiatus is diachronous, embracing more than 2 myr. All reported hiatuses record the eustatic falls. Consequently, we argue that eustatic processes controlled sedimentation in the Ciscaucasian basin throughout the entire Neogene. This means the basin was connected to the open ocean throughout this period, with important consequences for our understanding of watermass history in the Mediterranean and Paratethyan basins further west and south.

Many basins are filled under the influence of tectonics and variable climatically driven processes. Unravelling the relative contributions of these is generally easier in fossiliferous sequences if faunal diversity patterns are considered in conjunction with lithofacies analysis. This approach has been successfully applied to Late Miocene strata of Sicily, where progressive restriction and desiccation within the Sicilian Caltanissetta region occurred under a semi-arid climate during the Messinian Stage. This restriction was partly due to Antarctic cooling which produced Palaeo-Mediterranean sea-level oscillations during the Early Messinian, as a prelude to closure of the Atlantic connections. In addition, regions within this Afro-European plate collision zone were also subjected to syndepositional tectonic deformation associated with progressive perched basin development above foreland (south) verging thrust sheets. The relative impacts of climatic (eustatic) versus tectonic control on sedimentation patterns within these perched basins has been debated at length. However, progress towards resolving this problem by a combined approach involving lithofacies analysis, and faunal phase analysis provides clues for separating the effects of the controlling factors. Faunal phase analysis identifies general faunal associations with minimal emphasis on species diversity. The resulting 'phase' plots for Early Messinian strata appear to be transgression skewed when controlled by eustatic cyclicity, and regression skewed when driven by regional tectonics associated with perched basin tectonics. Keywords: Messinian, Sicily, faunal phase analysis, tectonics, eustasy.

Hot springs at Gongxiaoshe and Zhuyuan (maximum temperatures of 73 to 84°C, respectively) are characterized by deposits formed of calcite, aragonite, non-crystalline Si-Mg-Fe deposits, and minor amounts of barite and gypsum. The deposits at Gongxiaoshe are formed largely of alternating calcite and aragonite laminae, whereas those at Zhuyuan are formed largely of calcite. The calcite is in the form of: (i) pseudodendrites that grew as sub-crystals stacked upon each other; and (ii) unattached euhedral and incompletely formed dodecahedral and rhombohedral crystals. Amorphous Ca CO3, formed of nanoparticles <1 μm long, is common in some of the Zhuyuan deposits, but minor in the Gongxiaoshe deposits. The morphologically diverse arrays of aragonite crystals that lie parallel to bedding were not nucleated on a growth surface. Many substrates in these deposits are covered with reticulate coatings that are formed largely of Si and Mg with minor Fe and micro-granular coatings that are formed largely of Si and Fe. Biofilms, with their extracellular polymeric substances, and microbes are common at both springs. The compositionally and crystallographically diverse precipitates at these two springs are attributed to a biologically influenced model with precipitation taking place in micro-domains that developed in the extracellular polymeric substances. According to this model, precipitation varied at the micron-scale influenced by the elemental concentrations that developed in the hydrogel of extracellular polymeric substances. Critically, the very low preservation potential of the extracellular polymeric substance and its formative microbes means that the precipitates will rapidly lose evidence of their biotic origin. The compositional diversity of the precipitates, the crystallographic diversity of the calcite and aragonite with numerous incompletely formed crystals, and local concentrations of Si, Mg and Fe may, however, serve as proxies of that biologically influenced precipitation. [ABSTRACT FROM AUTHOR]