Open University Geological Society
Mainland Europe Branch ● OUGSME
AGM in Verona, Italy,
January 31st – February 1st, 2015
An introduction to the geology
of the Lessini Mountains area
Dr. Guido Gonzato
Open University Geological Society Mainland Europe - OUGSME
Verona is located at the
boundary between the
Southern Alps and the Po
plain, near Lake Garda.
The area belongs to the
African plate; the European
plate lies to the north of the
Giudicarie Line. Tectonic
lineaments are clearly
visible.
The Po Plain is the Alps'
foreland basin; Southern
Prealps are buried by
fluvial sediments.
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The Lessini Mountains
are mostly made of
Mesozoic (pink, blue,
green) and Cenozoic
(yellow) limestones.
Basalts and tuffs (purple)
are also common.
To the south of Lake
Garda, moraines were
left by upper Quaternary
glaciers. In the Po plain,
fluvial terraces were
formed by the Adige river.
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The stratigraphic column in the
Lessini Mountains is more than 1500
m thick.
Lower carbonate Formations
represent the evolution of a lateTriassic to middle-Jurassic
carbonate platform.
Due to tectonic activity, the platform
“drowned” during the Aalenian.
Deep-sea and basinal Formations
extend from Bajocian to
Maastrichtian.
Neritic conditions were restored
during the Eocene.
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Maiolica
Rosso Ammonitico
Oolite di S. Vigilio
Calcari Grigi
The local geomorphology makes it easy to spot the Formations.
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Calcari Grigi is often visible at the bottom of Lessini valleys.
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Beds with shells of Lithiotis problematica, a mollusc, are common.
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Cliffs are made of Oolite di S. Vigilio and topped by Rosso Ammonitico.
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Rosso Ammonitico outcrops commonly exhibit epikarst sculpturing.
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Rosso Ammonitico gets its name from the Ammonites it contains.
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Maiolica contains beds of chert, widely employed in prehistoric times.
AGM in Verona, Jan. 31-Feb. 1
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Scaglia Rossa is quarried and employed as building material.
AGM in Verona, Jan. 31-Feb. 1
Open University Geological Society Mainland Europe - OUGSME
It contains many fossils, such as Mosasaurus, sharks, ammonites.
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Ypresian
Maastrichtian
K-T
The K-T boundary is visible; the whole Palaeocene is missing.
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The most important fossils come from the Eocene Bolca Lagerst ätte.
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Eocene nummulitic limestones are common in the southern Lessini.
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Eocene basalt and tuff (mostly submarine eruptions) are also common.
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Karst features are very well represented, both on the surface...
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...and under the surface. Over 900 caves have been mapped.
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Our geological trip will focus on stratigraphy and karst
features in the Ponte di Veja area (20 km north of Verona,
near S. Anna d'Alfaedo).
In particular:
- the K-T boundary (Fiamene)
- Scaglia Rossa and overlaying tuff (Croce dello Schioppo)
- Maiolica and Rosso Ammonitico near Ponte di Veja
- palaeokarst fillings in caves around Ponte di Veja
- the Grotta dell'Orso palaeokarst cave.
Details will follow!
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