1,721,012 research outputs found
Did the Nile River flow to the Gulf of Sirt during the late Miocene?
No full textSatellite imageries from Landsat ETM+ and ERS (European Remote Sensing) Radar sensors, together with elevation data collected by the Shuttle Radar Topography Mission (SRTM) in addition to recent and older bibliography, have led to the hypothesis that, before the Late Messinian drawdown of the Mediterranean Sea, the River Nile flowed into the Libyan palaeo-Sirt. The study is still in progress; in this paper data are presented from three areas, showing evidence of palaeo-drainage of Tortonian-Late Messinian age, that could be considered sufficient to delineate the course of the Nile River up to the Gulf of Sirt (fig. 1)
Analysis of the relationships between DSGSD and brittle tectonics in southern Tuscany: Mount Civitella, Castell'Azzara (GR) [Analisi dei rapporti tra DGPV e tettonica fragile in Toscana meridionale: il Monte Civitella, Castell’Azzara (GR)]
No full textThe southern Tuscany territory is characterized by a wide range of lithologies and geological structures, due to poliphasic, compressional and extensional, northern Apennine evolution; subsequently gravitational processes, more or less deep, have complicated the geological framework. The Mt. Civitella represents an optimal example of gravitational and tectonics processes superimposition; this area is a good case of study to apply a multidisciplinary approach between traditional methodologies and technologically advanced methodologies, useful for the evolutionary models reconstruction, beginning from the brittle deformation, one of the most important causes for DSGSD. IN fact, the aim of this project is to comprise the relationships between brittle tectonics model and DSGSD (deep seated gravitational slope deformation) features
Did the Nile River flow to the Gulf of Sirt during the late Miocene?
No full textSatellite imageries coming from Landsat ETM+ and ERS (European Remote Sensing) radar sensors, together with elevation data collected by the Shuttle Radar Topography Mission (SRTM) in addition to recent and older bibliography, led to the hypothesis that, before the Late Messinian drawdown of the Mediterranean Sea, Nile River flowed to the Libyan palaeo-Sirt. The study is still in progress; in this abstract are presented data coming from three areas, that are showing evidences of palaeo-drainage of Tortonian-Late Messinian age, that could be considered sufficient to delineate the path of the Nile River up to the Gulf of Sirt
Neogene post - collisional evolution of the inner Northern Apennines: inferences from the upper Fiora Valley, southern Tuscany
No full textGeological map of the Chianti Mts (Northern Apennines, Italy)
No full textA detailed stratigraphical-structural survey combined with classical geological mapping has been performed in the
northern Chianti Mts, part of the Northern Apennines Orogen (central Italy). The study area can be subdivided in
different tectonic and depositional units: (i) the widely outcropping Tuscan Nappe (middle/late Lias–earliest
Miocene), thrusted to the west by (ii) Ligurian units (Cretaceous–Eocene) and unconformably covered by (iii)
post-nappe deposits (Pliocene–Pleistocene). The Chianti Mts are structured as a mega-antiformal fold,
dissected by WSW-ENE transversal lines and by NNW-SSE normal faults linked with the exhumation of the
Northern Apennines Range, developing a basin/ridge structure. As results, (i) a new improved stratigraphic
frame is here proposed; (ii) several tectonic and stratigraphic domains have been newly recognised; (iii) a large
area characterised by severe internal deformation has been recognised and mapped as an imbricate fan thrust
system, linked with transversal lines
Thrusting strike-slip tectonics and stratigraphic architecture in a thrust-belt belt (Chianti Mts, Northern Apennines)
No full textA detailed stratigraphical-structural geological survey combined with classical geological mapping has been performed in the northern Chianti Mts, part of the Northern Apennines Orogen (central Italy). The study area can be subdivided in some tectonic and depositional units: (i) the widely outcropping Tuscan Nappe (middle/late Lias - earliest Miocene), thrusted from the west by (ii) Ligurian units (Cretaceous-Eocene) and unconformably covered by (iii) post-nappe deposits (Pliocene - Pleistocene). The Chianti Mts are structured as a mega-antiformal fold, dissected by wsw-ene transversal lineaments, that likely forced both the pre-orogenic sedimentation, both the transpressional evolution of this sector of the Northern Apennines, and by nnw-sse normal faults linked with the exhumation of the Northern Apennines Range, developing a basin/ridge structure. As results: (i) a new improved stratigraphic frame is here proposed; (ii) several tectonic and stratigraphic domains, with differentiated stratigraphy and tectonic deformation have been recognised; (iii) a large area characterized by severe internal deformation has been recognised and interpreted as an imbricate fan thrust system, linked and controlled by transversal/strike-slip lineaments and by the stratigraphic architecture
Stratigraphic architecture of an outer ramp/basinal turbidite fan carbonate system in a foreland basin ("Scaglia Toscana" Fm., Chianti Mts, Northern Apennines, Italy)
No full textThe Chianti Mts, part of the Northern Apennines orogen, represent an ideal case study to depict the relationships between outer carbonate ramps and basin plain carbonate turbidite systems in foreland basins. The main object of this research is the "Scaglia Toscana" Fm., a ca. 200 metres thick Eocene-Oligocene succession of polychromous shales, marls, pelagic limestones and turbidite calcarenites, with marked lateral/vertical complexity, having its type-section in the Chianti Mts. During fieldwork, the fm. has been subdivided in four partially interfingered members (from the bottom and northernmost): Sugame Marls; Cintoia Shales; Montegrossi Calcarenites; Dudda Shales and Limestones. The formation relates to three depositional systems: a middle to outer carbonate ramp dominated by hemipelagic deposition; a basinal plain whose sediments distribution was mainly forced by redox/oxic conditions and calcite-lysocline fluctuations; a thinning- and fining-upward, coarse- to fine-grained carbonate turbidite system. The "Scaglia Toscana" basin was located on the Adria continental micro-plate, foreland of the developing Northern Apennines orogen, whose facies distribution was mainly controlled by block faulting and differential subsidence. The Chianti Mts. represent then a crucial sector, since they expose the junction between a northern SSE-dipping ramp and a southern basinal plain with turbidite floor fans. A general southwardand upward-shift from ramp, basinal plain and turbidite fan facies has been recognized and remarked since the pioneering studies of the 1960s. Nonetheless, an exhaustive facies and architectural analysis is still lacking in literature. To fill this gap, the partial and preliminary results of a field logging, integrated with sedimentary facies analysis are reported here. © 2011 Società Geologica Italiana, Roma
Sedimentary - tectonic evolution of the Parecchia Valley (Miocene - Pliocene, Marche - Romagna Apennines)
No full textNeogene post-collisional evolution of the internal Northern Apennines: insights from the upper Fiora and Albegna valleys (Mt. Amiata geothermal area, southern Tuscany)
No full textThe southern Tuscany represents the internal portion of the Northern Apennines. Its geological setting is particularly complicated due to two main tectonic phases: a first compressional syn-collisional phase (Late Cretaceous-Early Miocene) that led to nappe building and km-scale tectonic features; a later extensional post-collisional phase (Early Miocene-Pleistocene) led to uplift and unroofing of the thickened crust is linked to the anticlockwise Apennine rotation and Tyrrhenian Sea opening.
The upper valleys of the Fiora and Albegna rivers in southern Tuscany represent a key area to reconstruct the post-collisional tectonic and sedimentary evolution of this sector of the Apennine chain. This area is characterized by a tectonic nappe stack built during the syn-collisional phase, unconformably overlain by Miocene-Pliocene depositional units, referable to a few sedimentary cycles. The sedimentary-tectonic evolution for the study area, as recognizable by field data, is the result of a sequence of different deformative and depositional events. The compressive event (Early Miocene) led to crust thickening and emplacement of the Ligurian units onto the Tuscan Nappe. Later on, a first extensional event (Early-Middle Miocene) developed low-angle normal faults. This event was responsible of a strong tectonic elision and crustal thinning, forming the <>, characterized by a megaboudinage tectonic setting and developing structural-morphological depressions, probably seat of shallow-marine deposition. A second extensional event (Late Miocene) developed west-dipping listric normal faults, increasing the megaboudinage depressions. In the study area, the activity of west-dipping normal faults caused the deformation of the tectonic nappe stack with the development of regions with steep east-dipping attitude of bedding. In these regions cast-dipping normal faults affected the steep dipping bedding, so to form structural depressions in which tectonic delaminated slices, usually Ligurian units, were emplaced. Moreover, such structural depressions represented also the basins of the Late Miocene continental-marine sedimentation. A third extensional episode (Pliocene) developed with high-angle normal faults which dissected all the previous structures. During this extensional event graben and half-graben basins formed, and the Early Pliocene marine transgression with filling of deep elongated basins parallel to the chain, developed
Tectonic - sedimentary post - collisional evolution of a part of the inner northern Apennines: the upper Fiora and Albegna valleys, Southern Tuscany
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