Search results for "Calcar"
showing 10 items of 131 documents
Microbial acidification and pH effects on trace element release from sewage sludge.
2003
Leaching of sludge-borne trace elements has been observed in experimental and field studies. The role of microbial processes in the mobilization of trace elements from wastewater sludge is poorly defined. Our objectives were to determine trace element mobilization from sludge subjected to treatments representing microbial acidification, direct chemical acidification and no acidification, and to determine the readsorption potential of mobilized elements using calcareous sand. Triplicate columns (10-cm diameter) for incubation and leaching of sludge had a top layer of digested dewatered sludge (either untreated, acidified with H2SO4, or limed with CaCO3; all mixed with glass beads to prevent …
INTEGRATED CALCAREOUS PLANKTON BIOSTRATIGRAPHY OF SELECTED MIOCENE SUCCESSIONS IN THE NORTHERN CALABRIA (ITALY).
2005
An integrated calcareous plankton biostratigraphic approach on six sections cropping out in Northern Calabria allowed to define a revised chronostratigraphic framework for Tortonian-Messinian deposits. Four sections have been investigated in the Amantea Basin (Timpone Napoli, Vallone Salina, Case Vespano, and Cozzo Salice) and two in the Rossano Basin (Vallone Casino and Cozzo Sant'Isidoro). Biostratigraphic analyses have been based on quantitative counting of planktonic foraminifers and semiquantitative counting of nannofossils. The Timpone Napoli and Vallone Salina sections are Late Tortonian in age and referable to the Globorotalia suterae Zone. In terms of nannofossils zonal scheme thes…
Calcareous Nannofossil Biostratigraphy of the Central Mediterranean Basin during the last 430 000 years
2009
Quantitative analyses on over 2300 samples were carried ut on late Quaternary calcareous nannofossil assemblages from a central Mediterranean Sea sedimentary sequence (ODP Site 963A). Our results indicate that Emiliania huxleyi dominated the assemblages between 0 and 45.7 kyr BP; Gephyrocapsa muellerae between 45.7 and 177.3 kyr BP; small Gephyrocapsa between 177.3 and 263.5 kyr BP; Gephyrocapsa caribbeanica from 263.5 kyr BP down to the basal sample of our investigation, at about 430 kyr BP A comparison with similar reports from Atlantic Ocean sites indicates that the boundaries of the acme intervals identified in this study fall within the same Marine Isotopic Stages as the Atlantic Ocean…
EP07.12: Calcar avis: a normal cerebral anatomic structure that can also mimic parenchymal pathology
2019
Carbonate deposition and diagenesis in evaporitic environments: The evaporative and sulphur-bearing limestones during the settlement of the Messinian…
2015
The depositional and diagenetic processes involved in the formation of carbonates in the evaporitic environment of the Messinian Salinity Crisis are investigated in Southern Italy (Sicily and Calabria). Strong differences are observed between the studied sections that reflect specific depositional and diagenetic evolution in the interconnected sub-basins resulting from the syn-sedimentary tectonic fragmentation of the Central Sicilian and Calabrian domains. These carbonates formed diachronously in restricted perched sub-basins between the Tripoli Formation and the hypersaline settings of the MSC. The Calcare di Base (CdB) that can be interbedded with gypsum layers occurs rhythmically at the…
Sinkholes risk analysis: case history of Marsala (Sicily, Italy)
2006
Given the increasing phenomenon of Sinkholes all over Italy, the Gruppo Nazionale per la Difesa dalle Catastrofi Idrogeologiche (G.N.D.C.I) and the Dipartimento della Protezione Civile (D.P.C.), during 2004, started a plan called Sinkholes dedicated to the phenomena in Italy. The plan provides the publication of the database realized by the D.P.C. by means of the census of beyond 1000 cases scattered across the nation. The city of Marsala is strongly characterized by the presence of a great number of Calcarenite cavities. The material object of extraction is the Calcarenite di Marsala of the Pleistocene, frequently used in the construction of buildings. The presence of the underground cavit…
Preliminary Results on Recent Calcareous nannofossil Assemblages from the Central Mediterranean
2009
Response of calcareous nannofossils to late Quaternary orbital and suborbital climate changes: Evidence from central Mediterranean and Iberian Margin…
2009
Pseudomorphic transformation of amorphous calcium carbonate films follows spherulitic growth mechanisms and can give rise to crystal lattice tilting
2015
Amorphous calcium carbonate films synthesized by the polymer-induced liquid-precursor (PILP) process convert into crystallographically complex calcite spherulites. Tuning the experimental parameters allows for the generation of crystal lattice tilting similar to that found in calcareous biominerals. This contribution evidences the role of spherulitic growth mechanisms in pseudomorphic transformations of calcium carbonate.
Flexible minerals: self-assembled calcite spicules with extreme bending strength.
2013
Flexi-Fibers Glass or metal fibers can show incredible flexibility. Natalio et al. (p. 1298 ; see the Perspective by Sethmann ) used the protein silicatein-α, which is responsible for the biomineralization of silicates in sponges, to guide the formation of spicules made of calcite. These synthetic spicules could be bent to a high degree because of their inherent elasticity, whilst retaining the ability to guide light.