The Northern Apennine orogenic belt developed during subduction and collision between the Europe and Adria plates.The northernnmost sector of the nappe pile is dissected by several tectonic lines,whose kinematics and ...The Northern Apennine orogenic belt developed during subduction and collision between the Europe and Adria plates.The northernnmost sector of the nappe pile is dissected by several tectonic lines,whose kinematics and age are crucial for the understanding of the Northern Apennine evolution,and its mutual relationships with the neighbouring Alps.Between these,the Ottone-Levanto line still lacks an unambiguous geodynamic interpretation,because of lacking of well-exposed outcrops.We describe unique fault rocks exposures representative of the Ottone-Levanto line whose structural features indicate deformation with components of contraction through top-to-the-NE thrusting and contemporaneous top-tothe-SW sinistral/dip-slip shearing.The collected data coupled with regional and map-scale evidences indicate that the Ottone-Levanto line acted as a sinistral transpressional shear zone during the Late Eocene-Early Oligocene.Placing our data in the regional context allows correlating the Ottone-Levanto line with surrounding lines dissecting the Alpine-Apennine junction.We propose that the Ottone-Levanto developed in a conjugate system during collision and northward displacement of the Adria plate,resulting in east-and westward thrusting of the Alpine-Apennines orogenic core.展开更多
Environmental contamination has become a global problem of increasing intensity due to the exponential growth of industrialization. One main debated issue is the metal contamination of rivers receiving Acid Mine Drain...Environmental contamination has become a global problem of increasing intensity due to the exponential growth of industrialization. One main debated issue is the metal contamination of rivers receiving Acid Mine Drainage(AMD) from active/abandoned mines. In order to assess the quality of lotic systems, diatoms are commonly used, as their assemblage modifies on the basis of changes in environmental parameters. Benthic diatom changes were analyzed along the metal-impacted Gromolo Torrent(Liguria, NW Italy) with the aim of understanding the effects of input from the abandoned Libiola Cu mine. The results support the hypothesis that metals from AMD lead to massive changes in diatoms, resulting in low biological diversity and in a shift of dominance, passing from the genera Cymbella and Cocconeis to more tolerant and opportunistic species, such as Achnanthidium minutissimum and Fragilaria rumpens. The high concentrations of labile metals, measured through Diffusion Gradients in Thin-films(DGT) immediately downstream of the two AMD inputs in the torrent, corresponded to a sudden decrease in the presence of diatoms, indicating the possible reaching of acute toxic levels. In particular,A. minutissimum dominated the mining area and was positively correlated with Cu and Zn;whereas F. rumpens bloomed downstream of this area, where the metal content was diluted,and was positively correlated with As and Pb. Finally, an important abundance of Nitzschia palea and teratological forms of A. minutissimum and F. rumpens were observed downstream from the mine, indicating that metals may have an important impact on diatoms up to the torrent mouth.展开更多
基金supported by funds ATENEO grant by Pisa University,and by C.N.R(Istituto di Geoscienze e Georisorse,Unita Operativa di Pisa).
文摘The Northern Apennine orogenic belt developed during subduction and collision between the Europe and Adria plates.The northernnmost sector of the nappe pile is dissected by several tectonic lines,whose kinematics and age are crucial for the understanding of the Northern Apennine evolution,and its mutual relationships with the neighbouring Alps.Between these,the Ottone-Levanto line still lacks an unambiguous geodynamic interpretation,because of lacking of well-exposed outcrops.We describe unique fault rocks exposures representative of the Ottone-Levanto line whose structural features indicate deformation with components of contraction through top-to-the-NE thrusting and contemporaneous top-tothe-SW sinistral/dip-slip shearing.The collected data coupled with regional and map-scale evidences indicate that the Ottone-Levanto line acted as a sinistral transpressional shear zone during the Late Eocene-Early Oligocene.Placing our data in the regional context allows correlating the Ottone-Levanto line with surrounding lines dissecting the Alpine-Apennine junction.We propose that the Ottone-Levanto developed in a conjugate system during collision and northward displacement of the Adria plate,resulting in east-and westward thrusting of the Alpine-Apennines orogenic core.
文摘Environmental contamination has become a global problem of increasing intensity due to the exponential growth of industrialization. One main debated issue is the metal contamination of rivers receiving Acid Mine Drainage(AMD) from active/abandoned mines. In order to assess the quality of lotic systems, diatoms are commonly used, as their assemblage modifies on the basis of changes in environmental parameters. Benthic diatom changes were analyzed along the metal-impacted Gromolo Torrent(Liguria, NW Italy) with the aim of understanding the effects of input from the abandoned Libiola Cu mine. The results support the hypothesis that metals from AMD lead to massive changes in diatoms, resulting in low biological diversity and in a shift of dominance, passing from the genera Cymbella and Cocconeis to more tolerant and opportunistic species, such as Achnanthidium minutissimum and Fragilaria rumpens. The high concentrations of labile metals, measured through Diffusion Gradients in Thin-films(DGT) immediately downstream of the two AMD inputs in the torrent, corresponded to a sudden decrease in the presence of diatoms, indicating the possible reaching of acute toxic levels. In particular,A. minutissimum dominated the mining area and was positively correlated with Cu and Zn;whereas F. rumpens bloomed downstream of this area, where the metal content was diluted,and was positively correlated with As and Pb. Finally, an important abundance of Nitzschia palea and teratological forms of A. minutissimum and F. rumpens were observed downstream from the mine, indicating that metals may have an important impact on diatoms up to the torrent mouth.
