Abstract: The Upper Ordovician (Edenian) Lindsay Formation of the Ottawa Embayment represents the final stage of carbonate platform development in the Taconic foreland periphery inboard of the northern Appalachian orogen. The succession overlies a narrow (~60 km) axis of a Neoproterozoic Laurentian rift extending across the Grenville orogen. The Lindsay Formation consists of a lower heavily bioturbated skeletal limestone that represents a warm-water shoal facies following an underlying outer ramp stratigraphy, and an upper division of renewed deep-water deposition with organic-rich shale and fossiliferous lime mudstone. Pyritic deep-water black shale of the westerly advancing Taconic foreland basin disconformably overlies this platform succession. Stratigraphic correlation through the central embayment identifies likely synsedimentary faults and seaward-directed erosion bounding the Lindsay Formation in a region of older Ordovician faults and a change in the lithotectonic character of the crystalline basement. The Late Ordovician shallowing and localization of structural/erosional features are interpreted to record a structural hinge: a local accommodation to, first, foreland periphery uplift, then rapid subsidence related to westerly diachronous foreland subsidence through the platform interior. Spatial association of structures of differing ages suggests that reactivation of inherited weakened crust influenced Late Ordovician sedimentary patterns.
Abstract: The tectonically active East Sierra Valley System (ESVS), which comprises the westernmost part of the Walker Lane-Eastern California Shear Zone, marks the boundary between the highly extended Basin and Range Province and the largely coherent Sierra Nevada-Great Valley microplate (SN-GVm), which is moving relatively NW. The recent history of the ESVS is characterized by oblique extension partitioned between NNW-striking normal and strike-slip faults oriented at an angle to the more northwesterly relative motion of the SN-GVm. Spatially variable extension and right-lateral shear have resulted in a longitudinally segmented valley system composed of diverse geomorphic and structural elements, including a discontinuous series of deep basins detected through analysis of isostatic gravity anomalies. Extension in the ESVS probably began in the middle Miocene in response to initial westward movement of the SN-GVm relative to the Colorado Plateau. At ca. 3–3.5 Ma, the SN-GVm became structurally separated from blocks directly to the east, resulting in significant basin-forming deformation in the ESVS. We propose a structural model that links high-angle normal faulting in the ESVS with coeval low-angle detachment faulting in adjacent areas to the east.
Abstract: The conservation of the historic stone heritage has great importance when this material characterizes the image of a city, as it happens in Syracuse (Sicily). Its historical buildings are afflicted by a heavy state of deterioration due to the particular microclimate, to pollution and to neglect endured over time. This article reports the investigations made on limestone samples from historic façades of the city and from the neighboring quarries still in operation, in order to understand the petrographic typology, the reaction to the degradation over time, the possible maintenance and recovery interventions, and the correct applications in buildings of new construction. For this aim, bulk and surface analysis have been made both on the quarry materials and on the corresponding aged materials. It is therefore possible to define the types of rock most suitable for the use in contemporary architecture guaranteeing criteria of perfect biocompatibility. In this way a natural material can be employed in traditional and innovative uses and ensure both the sustainability of the interventions and the continuity of a consolidated tradition.
Abstract: The investigation of the contamination in soil, plants and groundwater revealed a spatial evolution, with an increasing trend in the Cr, Fe, Ni, Mn and Co contents in soils from the Assopos to Thiva basin, followed by C. Evia and Ni-laterite deposits, suggesting that the latter and their parent ophiolites are a potential source for these metals. In contrast, the contamination in groundwater by Cr(VI), ranging from 2 to 360 μg/L Cr, and a varying degree of salinization is probably due to both human activities and natural processes. A diverse source for the contamination of soil and groundwater in the Assopos-Thiva basins is consistent with the increasing trend of the Mg/Si ratio and Cr(VI) concentration in water. The use of deep karst-type aquifer instead of the shallow-Neogene one may provide a solution to the crucial environmental problem. The selective extraction by EDTA and alkaline solution showed that Cr and Fe are less available than Mn. The Cr contents in plants range from <1 to tens of mg/kg, due probably to the high resistance of chromite. However, the average Crtotal contents in plants/crops are higher than normal or sufficient values, whilst Crtotal accumulation [(% metals in plants × 100)/metal in soil] and Cr(VI) accumulation are relatively low. There is a very good positive correlation between accumulation factors for Cr and Fe (R2 = 0.92), suggesting a similarity concerning their uptake.
Abstract: The Quaternary mammals of Sicily are well known, and five faunal complexes have been distinguished on the basis of bioevents (extinctions and new arrivals) and evolution of endemic species. It is clear that the composition of mammal faunas is strictly related to the dispersal ability of each species and to the paleogeography of the area. Until now, researches have chiefly attributed paleogeographical changes as controlling these dispersals: the sea strait between the island and the Italian peninsula has had different widths and depths over time, operating different kinds of filters on the spreading of terrestrial mammals. Moreover, Sicily and its nearby mainland underwent changes in paleogeography. Some incongruence in bioevents has been attributed to the filter operated by the marine strait, which could have acted in differential ways on large and small mammals. However, the roles of ecological interactions among vertebrate species and their control on bioevents have been greatly underestimated. In this critical review, changes in mammals’ associations are reconsidered not only in terms of biochronology and dispersal ability of taxa through the marine strait, evolution of endemic features, in addition to the paleogeography of the island, but also considering the ecological role of each species and the interactions among the species with each faunal complex.
Abstract: Serpentinites are used in both exterior and interior locations, but not all serpentinites are equal: they vary in physical-mechanical behavior and are not all suitable for similar uses. The serpentinites most commonly used worldwide come from India, Pakistan or Egypt. Spain has traditionally quarried two ultramafic massifs, one in Galicia (Verde Pirineos) and one in Andalucía (Verde Macael). Some of these quarries were small family-run businesses. In both cases, these rocks are commercially available as “green marble.” These serpentinites commonly have a high degree of carbonation, but the process does not always take place with the same intensity. Carbonate can act as a cementing agent of the other phases, increasing the mechanical strength parameters. As a result, an improvement in the strength conditions is achieved, but a misinterpretation of the suitability of the rock may occur because a perception among users that “green marble” is similar to geologically defined marble. This may lead to inappropriate applications as an ornamental stone. At a time of economic crisis in Europe, the natural stone sector is encouraged to invest in research to identify the best quality products that can compete profitably with those currently being imported from other countries. This paper provides a comparison of properties of the Verde Macael serpentinite with a true marble in the hope of contributing to improving the natural stone industrial sector.
