Luca Basilone

WALKING ALONG A CRUSTAL PROFILE ACROSS THE SICILY FOLD AND THRUST BELT

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Geology of Monte Gallo (Palermo Mts, NW Sicily)

ABSTRACT The promontory of Monte Gallo (Palermo, NW Sicily) is a spectacular site where Upper Triassic-Eocene carbonate platform rocks and Quaternary continental to marine deposits are well exposed. A Mesozoic-Paleogene rock succession allows the potential visitor to easily detect the features and the evolution of the Panormide carbonate platform, a shallow-water paleogeographic domain of the Southern Tethyan margin. Quaternary deposits, as well many landforms, enable the visitor to directly identify the interplay between climate changes, tectonics and fluctuations of marine level that occurred during the Quaternary Period. A detailed geological map (1:15,000 mapping scale) is presented, accompanied by a stratigraphic correlation of logged sections and morpho-stratigraphic and tectonic schemes of the area, aimed at highlighting the geological heritage of Monte Gallo in support of the establishment of a Geosite. The Geological Map and relevant explanatory notes should be used as cartographic support and as a field trip guide for possible geological itineraries.

Permian-Cenozoic deep-water carbonate rocks of the Southern Tethyan Domain. The case of Central Sicily

We present an integrated stratigraphy of the outcropping and buried Permian-Cenozoic deep-water carbonate successions, forming some of the tectonic units mostly buried beneath the Late Neogene sedimentary cover in the fold and thrust belt of Central Sicily. Three main successions, pertaining to the well known Lercara, Imerese and Sicanian domains, have been reconstructed on the basis of a detailed facies analysis, seismostratigraphic interpretation, bio -stratigraphy (mostly based on palynological data) and comparison between outcropping and subsurface deep-water sediments. The main results reveal a continuous sedimentation of the deep-water Southern Tethyan Sicilian succession since the Permian to Cenozoic. In detail: a ) the Permian-Middle Triassic terrigenous and carbonate deep-water successions, outcropping or buried in the Cerda, Lercara-Roccapalumba and Sosio Valley regions, are well comparable to each other and represent the common substrate of the Mesozoic-Paleogene Imerese and Sicanian carbonate successions; b ) the Mesozoic-Paleogene deep-water carbonates, when compared among them, reveal the occurrence of different sedimentary successions (Imerese and Sicanian); c ) the Oligo-Miocene foreland basin terrigenous sediments (Numidian flysch) clearly differ from the coeval foreland pelagic to open-shelf carbonates. The paleogeographic reconstruction envisages: a ) during the Permian-Triassic, a wide subsident continental rifting area, bordered by a shallow-water domain periodically supplying the basin with calciturbiditic to gravity flows sedimentation (rift stage of the Southern Tethyan margin); b ) during the Jurassic-Paleogene, two different deep-water basins developed in a context of a post-rift stage. The different sedimentation reflects the location of the Imerese and Sicanian basins, respectively, along adjacent rimmed shelf and stepped carbonate platform margins.

Subsurface Geometries in Central Sicily FTB as a Premise for Hydrocarbon Exploration

The study concerns a sector of the Maghrebian Sicilian Fold and Thrust Belt (FTB), located in central Sicily between the southern edge of the Madonie Mts. and the Caltanissetta trough. Interpretation of recently acquired seismic profiles, constrained by joint detailed stratigraphy and field investigation, revealed the structure of the study area as formed by a thick pile of deep water carbonate (Imerese and Sicanian) thrusts lying on carbonate platform imbricates. In the forward migration of the FTB, two main tectonic events were envisaged; shallow and deep seated thrusts occurred during the Miocene-early Pleistocene time interval that deformed the former sedimentary cover of the continental margin. The kinematic model and the occurrence, at depth, of carbonate platform rock bodies indicate the study area as a potential frontier for hydrocarbon opportunities.

Quaternary marine and continental unconformity-bounded stratigraphic units of the NW Sicily coastal belt

ABSTRACT In the coastal sector of NW Sicily, the regional correlation of relevant unconformities recognised within the Quaternary sedimentary successions allowed the mapping of seven unconformity-bounded stratigraphic units (UBSUs). The regional unconformities are marine or subaerial erosional surfaces, as well as non-depositional surfaces, locally marked by paleosoils. The erosional surfaces were produced from marine abrasion, surface water overland/concentrated flow, river erosion, karst solution, mass movement, or wind erosion. The main lithofacies of the Quaternary UBSUs consist of: (a) marine and coastal bioclastic calcarenites, (b) aeolian sandstones, (c) river deposits, (d) colluvial deposits, (e) talus slope deposits, (f) landslide deposits, and (g) chemical carbonates (travertines and speleothems). Quaternary environmental changes, due to tectonics, climate, and sea-level oscillations, are the causes that favoured the development of erosion/deposition processes responsible for the genesis of unconformities and deposits. As a result, through the UBSU map of the NW Sicilian coastal belt, it is possible to: (i) recognise stratigraphic units controlled by tectonic, climatic, and environmental processes (and their interplay) and (ii) detect Quaternary sedimentary evolution.

Lithostratigraphy of Sicily

This introductive section regards a synthetic description of the regional geological setting of the Sicily island. The main stratigraphy and regional distribution of the Sicilian rock units and the paleogeography and paleo-tectonics of the Permo-Mesozoic carbonates is included. Furthermore, an overview on the stratigraphic classification principles is provided to facilitate the reader in understanding the terminology used in the main body of text. Sicily, located between the Calabrian Arc and the chains of North Africa is considered a key area for an understanding of the very complex geological history of the Central Mediterranean. It is characterised by different rocks, a large variety of sedimentary sequences, volcanism and tectonic structures developed during the Paleozoic–Quaternary time interval (Fig. 1.1). Metamorphic, igneous and sedimentary rocks pertaining to different geological domains (Europe, Africa and Tethys) and widely outcropping in Sicily have promoted several geological research projects since the end of the 1800s, which have had a strong impact on the description and definition both of the Sicilian regional geological setting and sedimentary sequences. The complexity of the sedimentary successions lies in the understanding of their manner, time and place of formation and therefore must be analysed by considering various aspects and according to different criteria (see Bosellini et al. 1989). The simplest and most immediate way to differentiate the rocks of a sedimentary succession is by taking account of their lithological differences. This method allows a sedimentary body within a given area and in a specific stratigraphic sequence to be distinguished and defined. This method, which requires specific criteria based on physical observations, is defined as the lithostratigraphic classification. Generally, the advancement of geological knowledge, which includes the stratigraphic knowledge of the Sicilian sedimentary sequences, has always corresponded to historical moments of human progress, during which significant economic and social benefits were produced. At the end of the 1800s, the progress of geological research in Italy was accelerated by the realization of the Geological Map of Italy at 1:100,000 scale (proposed by the Royal Italian Geological

Mountain building in NW Sicily from the superimposition of subsequent thrusting and folding events during Neogene: structural setting and tectonic evolution of the Kumeta and Pizzuta ridges

ABSTRACT We present a 1:25.000 scale geological map of the Kumeta-Pizzuta ridge in north-western Sicily (Italy), achieved by integrating stratigraphic, structural and geophysical data. In this area, the tectonic edifice results from the piling-up of deep-water-, carbonate platform- and pelagic platform-derived tectonic units (Imerese and Sicilide, Panormide and Trapanese domains, respectively) resulting from deformations of the former southern Tethyan continental margin. The structural setting shows interference of tectonic events, different types of structural styles and different scales of deformational patterns. Early overthrust of the Imerese on the Trapanese units (since the late Serravallian) was followed by wedging at depth of the Trapanese units (after the Tortonian). The wedging implied re-embrication and shortening into the overlying Imerese tectonic units and so produced the main folding and compressive to transpressive structures along the Kumeta-Pizzuta Ridge. Seismic reflection profiles integrated with field data reveal that the main E-W-trending anticlines have been offset by high-angle reverse faults flattening at depth until they connect with low-angle, regionally widespread, decollement surfaces with a northward tectonic transport. This setting supports backthrusting along transpressional faults in the study area, ruling out that the Kumeta ridge is a positive flower structure related to a near-vertical deep, crustal, shear zone as formerly suggested.

Introduction to the Geology of Sicily

This introductive section regards a synthetic description of the regional geological setting of the Sicily island. The main stratigraphy and regional distribution of the Sicilian rock units and the paleogeography and paleo-tectonics of the Permo-Mesozoic carbonates is included. Furthermore, an overview on the stratigraphic classification principles is provided to facilitate the reader in understanding the terminology used in the main body of text.

Sicilian Lithostratigraphic Units

This chapter includes the description of the Sicilian lithostratigraphic units (Fig. 2.1). They are grouped in a generally chronological order and the complete list of the worksheets is shown in the Table of contents. In each chronologic group the worksheets of the described formations are organized in alphabetic order. The Permo-Triassic units are the oldest deposits outcropping in Sicily that originated during the early stages of the Southern Tethyan continental rifting. The Meso-Cenozoic carbonate units represent the sedimentary sequences of the various stratigraphic successions differentiated in the field along the Sicilian outcrops. The deposits of the Sicilide Complex (Tethyan units) and the Tertiary clastics (Numidian flysch) are grouped separately. The Miocene and the Plio-Pleistocene units represent the sedimentary cover of the wedge-top basins formed during the construction of the Sicilian FTB. The Quaternary continental and marine deposits are classified as Unconformity-Bounded Stratigraphic Units (UBSUs).

Extensive backthrusting features in the northern Sicily continental margin highlight a late collisional stage of the Sicilian Fold and Thrust Belt

Abstract from 88th Congress of the Italian Geological Society, 2016-09-07 - 2016-09-09, NaplesAbstract from 88th Congress of the Italian Geological Society, 2016-09-07, 2016-09-09, Naplesbook Edited by D. Calcaterra, S. Mazzoli, F.M. Petti, B. Carmina & A. Zuccari doi: 10.3301/ROL.2016.79