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Le piattaforme carbonatiche triassiche delle Pale di San Martino (Dolomiti)
No full textThe Pale di San Martino massif is not formed by a single dolomitic lithosome, but includes two carbonate platforms: Dolomia dello Sciliar (Ladinian) and Dolomia Cassiana (Carnian). On the Pale di San Martino plateau the Dolomia dello Sciliar shows an emersion surface characterized by karstik cavities, breccias and sedimentary dykes; the Ladinian carbonate platform died owing to a relative sea-level fall. On the plateau the Dolomia Cassiana disconformably overlies the Dolomia dello Sciliar, while at Vallone delle Lede head it progrades over a basinal unit (San Cassiano formation) laying in a depression developed into the Ladinian carbonate body.
A regional transcurrent setting is suggested to explain the tectonic events, which affected the Dolomia dello Sciliar at the end of the Ladinian time
L'anticlinale di rollover liassica dei Sogli Bianchi nel Monte Pasubio (Vicenza)
No full textThe Sogli Bianchi face in the Pasubio Massif (Venetian Alps) shows a well exposed roll-over anticline. The structure originated by a hanging wall bending in response to slip on a normal listric fault dipping towards the SE. The age of the deformation suggests that the rapid Sinemurian relative sea-level rise recorded throughout the Trento platform by the deposition of the oolitic Middle Member of the Calcari Grigi Fm was caused by a tectonic collapse
Significato strutturale della “Flessura Corno d’Aquilio-Monte Belfiore” nei Monti Lessini (Verona)
No full textIn the Verona lessini Mountains the Corno d'Aquilio-Monte Belfiore flexure is reinterpreted as a thrust-fold structure with a general ESE-WNW trend
Modello strutturale della deformazione estensionale paleogenica nella ex-cava Main (Arzignano, Vicenza)
Full text linkIn the eastern Lessini Mountains (Vicenza) at the confluence of the Chiampo and Agno valleys on the southern slope of Monte Main, a "Chiampo marble" quarry was active in the 1980s, well known for its very rich paleontological finds. The exceptional exposure produced by the excavation, is approximately parallel to the extension direction of the Alpone-Agno graben, a Paleogene structure coeval with the mafic to ultramafic magmatism of the western Veneto and the southern Trentino,. This allowed the observation of several normal faults which accommodated the extension. Three carbonate banks interlayered with stratified basaltic epiclastics show an eastern dip increasing downwards, while the thickness of the stratified epiclastics increases rapidly eastwards. The triangular-shaped section, presently partly obliterated and inaccessible, could be interpreted as the infilling of a basin developed on the hanging wall of a synsedimentary listric fault dipping west, or on the roof of a hectometric carbonate block eastward tilted in a domino model. At a larger scale the domino style is shown also by the intermediate carbonate bank. This deformation style explains well the rapid thickness variations of the epiclastics observed throughout the entire graben area
Grande atlante delle rocce e dei minerali
No full textPartendo dall'esame delle meteoriti, materiale che ci fornisce informazioni sulla composizione del sistema solare, il testo si sviluppa nelle fasi di differenziazione avvenute nel nostro pianeta, che hanno portato alla formazione della crosta, del mantello e del nucleo. L'atlante mostra un significativo esempio della straordinaria varietà di rocce e di minerali della crosta
Elementi di geologia
Full text linkThe Montello hill is an uplifting anticline
structure located in the front of the Neogene-
Quaternary Venetian Alps chain. It’s made of
Messinian (ca 6.5-5.3 Ma) rocks deposited in a
transitional marine to continental environment.
These are conglomerates and sandstones with
calcite cement alternating with mudstones
(Montello Conglomerate). The Montello
Conglomerate belongs to the South-Alpine
Molasse deposited in a foredeep which
development started from the Serravallian
onward. The maximum thickness of the Messinian
unit is 1800 m and the depositional coarsening
and shallowing upward trend points to a rapid
filling of the foredeep. The clast composition of
the conglomeratic levels is mainly carbonatic
(Mesozoic limestones and dolomites) but older
magmatic and metamorphic pebbles testifying the
erosion level of the northern source areas are also
present. The lowermost Messinian deposits are
represented by a number of cycles consisting of
shallow-marine to brackish-water mudstones and
sandstones, associated with fluvial/alluvial-fan
conglomerates and sandstones. These deposits
represent the last record of a marine influence.
The continental succession mainly consists of an
alternation of lacustrine deposits and alluvial-fan
conglomerates. Major fan bodies entered from the
north in a lacustrine basin probably hydrologically
closed, i.e. without waters outflowing into the
Mediterranean. Four megasequences were
recognized at a regional scale. They may be
explained as cyclic pulsating tectonic episodes or
interaction of relatively continuous deformation
with climatically modulated cyclical changes in
the regional base level.
Recent investigations by means of seismic
profiling (TRANSALP) show that the Montello
anticline lies over a ramp of a south-vergent blind
thrust (Montello thrust), which is the frontal thrust
of the Venetian belt. The back limb of the fold is
deformed by an antithetic reverse fault (Montello
backthrust) cropping out on the south slope of the
Col Cesen. Therefore, the overall geometry of the
Montello structure is that of a pop-up.
The Montello hill is located at the mid point
between the Schio and Gemona lateral tips of the
eastern South Alpine belt front, which shortening
absorbs part of the convergence between Africa
and Europe. The 1976 destructive earthquakes of
the Friuli are the last prominent episode of such
fault activity. Although the Montello thrust
exhibits little evidence of Quaternary activity
(778?, 1268, 1857-60 A.D.), the history of its
folding and uplift may be unravelled by the
analysis of the seven Quaternary terraces mainly
developed on the eastern side of the Biadene
valley through the erosion of the palaeoPiave. The
present-day Piave river flows eastward along the
north side of the hill. Instead of the anticline
growth, responsible for the westward shift of the
river course recorded by the westward younging
set of terraces, the eastward river deviation has
been ascribed to the glacial history of the region
Ex cava di marmo grigio-perla (marmo a brucite)
No full textLa cava fu aperta negli anni Cinquanta del secolo scorso, quando nelle Prealpi vicentine, trentine meridionali e veronesi erano in funzione una ottantina di cave dello stesso tipo. Vi si estraeva il marmo Grigio-perla (marmo a brucite), una roccia metamorfica prodotta dal termometamorfismo della dolomia (parte superiore dell’unità Dolomia Principale, del Trias superiore) indotto dall’intrusione di filoni di magma basaltico (vulcanismo paleogenico del Veneto occidentale e Trentino meridionale
Humankind as geological super-agent and the Anthropocene predicament
No full textHumans move tremendous amounts of soil and rock. Construction and mining activities account for about 30% of all the material transported, while the remaining 70% is unintentionally moved as by-product of agriculture. Natural processes have lowered continental surfaces by a few tens of meters per million years. In contrast, human activities lower continental surfaces by a few hundred meters per million years. This difference makes Homo sapiens the most important geomorphic agent, who has modified nearly 80% of the ice-free area in both the form and sediment fluxes of the landscapes. The emergence of the new epoch Anthropocene, different from the relatively stable Holocene epoch, makes clear that global population and economic growth are challenging the safe operating space for humanity. In particular, two core boundaries – climate change and biosphere integrity – have been identified. The climate change due to Earth energy imbalance following the carbon cycle perturbation requires a rapid exit from fossil fuel use and the adoption of low-carbon technologies to produce energy. This paradigm shift in energy production and consumption, will require a wide range and high quantities of minerals and materials to meet the rapidly growing need for more wind turbines and solar PVs. The clean energy transition will be significantly mineral intensive. In turn, mining will continue to affect the ecosystems, through fossil fuel use, deforestation, fragmentation of biomes, biodiversity loss, freshwater exploitation and contamination. The Anthropocene predicament cannot be solved the way a problem is solved. The answer is not simply scientific and technological, but also social, cultural and political.Humans move tremendous amounts of soil and rock. Construction and mining activities account for about 30% of all the material transported, while the remaining 70% is unintentionally moved as by-product of agriculture. Natural processes have lowered continental surfaces by a few tens of meters per million years. In contrast, human activities lower continental surfaces by a few hundred meters per million years. This difference makes Homo sapiens the most important geomorphic agent, who has modified nearly 80% of the ice-free area in both the form and sediment fluxes of the landscapes. The emergence of the new epoch Anthropocene, different from the relatively stable Holocene epoch, makes clear that global population and economic growth are challenging the safe operating space for humanity. In particular, two core boundaries – climate change and biosphere integrity – have been identified. The climate change due to Earth energy imbalance following the carbon cycle perturbation requires a rapid exit from fossil fuel use and the adoption of low-carbon technologies to produce energy. This paradigm shift in energy production and consumption, will require a wide range and high quantities of minerals and materials to meet the rapidly growing need for more wind turbines and solar PVs. The clean energy transition will be significantly mineral intensive. In turn, mining will continue to affect the ecosystems, through fossil fuel use, deforestation, fragmentation of biomes, biodiversity loss, freshwater exploitation and contamination. The Anthropocene predicament cannot be solved the way a problem is solved. The answer is not simply scientific and technological, but also social, cultural and political.Humans move tremendous amounts of soil and rock. Construction and mining activities account for about 30% of all the material transported, while the remaining 70% is unintentionally moved as by-product of agriculture. Natural processes have lowered continental surfaces by a few tens of meters per million years. In contrast, human activities lower continental surfaces by a few hundred meters per million years. This difference makes Homo sapiens the most important geomorphic agent, who has modified nearly 80% of the ice-free area in both the form and sediment fluxes of the landscapes. The emergence of the new epoch Anthropocene, different from the relatively stable Holocene epoch, makes clear that global population and economic growth are challenging the safe operating space for humanity. In particular, two core boundaries – climate change and biosphere integrity – have been identified. The climate change due to Earth energy imbalance following the carbon cycle perturbation requires a rapid exit from fossil fuel use and the adoption of low-carbon technologies to produce energy. This paradigm shift in energy production and consumption, will require a wide range and high quantities of minerals and materials to meet the rapidly growing need for more wind turbines and solar PVs. The clean energy transition will be significantly mineral intensive. In turn, mining will continue to affect the ecosystems, through fossil fuel use, deforestation, fragmentation of biomes, biodiversity loss, freshwater exploitation and contamination. The Anthropocene predicament cannot be solved the way a problem is solved. The answer is not simply scientific and technological, but also social, cultural and political
Tertiary Extension in the Southern Trento Platform, Southern Alps, Italy
No full textThe southern Trento Platform (Southern Alps, NE
Italy) was the locus of abundant mafic volcanism associated
with Paleogene extensional tectonics. During the Paleocene
and throughout the Eocene, a NNW-SSE trending graben (the
Alpone-Agno Graben (AAG)) developed in the eastern Lessini
Mountains. The graben was filled with basaltic volcaniclastics,
calcarenites, and lava flows. The AAG is a half-graben
system probably bounded by rotational listtic normal faults.
Most faults in the graben dip towards the WSW. Paleostress
analysis within the AAG shows that during the Eocene the direction
of horizontal extension was ENE-WSW. The volcanic
activity continued into the Oligocene; however, the relation
between Oligocene tectonics and volcanism remains unclear.
Gravimetric and magnetic anomalies in conjunction with the
crustal thickness variations suggest a locus of lithospheric
thinning slightly off-axis from the AAG. This can be explained
by an overall asymmetric extensional geometry dominated
by a WSW dipping detachment fault. The Paleogene
geodynamic scenario of the Trento Platform suggests that the
AAG developed as a foreland extensional response to the active
collisional convergence between the European and
Adriatic plates. Neogene compressional tectonics reactivated
some of the Paleogene normal faults as strike-slip faults
Segmentation and linkage of the Lessini Mountains normal faults, Southern Alps, Italy
Full text linkThe Lessini Mountains on the southern margin of the Italian Southern Alps exhibit two Tertiary graben systems
at an angle of about 40°. The NNW-trending system is orthogonal to the ENE-trending Tertiary extension direction.
The NNE-trending system parallels the neighbouring Jurassic western margin of the Trento Platform and experienced
sinistral transtension during the Paleogene. The interaction between the two normal fault trends defines a ca. 8 km
long and 6 km wide rhomb-shaped structure containing igneous intrusions and dolomitized rock bodies, suggesting
that the structure controlled syn-extensional fluid migration. At a smaller scale, fault segments of the NNE-trending
set show two basic types of transfer zones, i.e. conjugate and synthetic. Due to the sinistral and normal oblique-slip
on these faults, left steps of en e ́chelon segments had a kinematics similar to that of pull-apart structures. The location
of intrusion-centres within such transfer zones led to the collapse of the roof of the magma chambers and consequent
deep basins development. In contrast, right-stepping synthetic en e ́chelon normal-oblique fault segments developed
relay ramps. © 2000 Elsevier Science B.V. All rights reserved
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