Umbria -Marche Apennines Geological Field Trip Marco Menichetti, Rodolfo Coccioni
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Umbria -Marche Apennines geological field trip Marco Menichetti, Rodolfo Coccioni To cite this version: Marco Menichetti, Rodolfo Coccioni. Umbria -Marche Apennines geological field trip. 2013, 2013, Livret-Guide des Excursions du Groupe Français du Crétacé. hal-01236473 HAL Id: hal-01236473 https://hal.archives-ouvertes.fr/hal-01236473 Submitted on 1 Dec 2015 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Excursion du Groupe Français du Crétacé Umbria - Marche Apennines geological field trip Leaders: Marco Menichetti Rodolfo Coccioni Department of Earth, Life and Environmental Sciences Urbino University - Italy Gubbio - Italy 3 - 7 June 2013 LOGISTIC The excursion will start and end at Rome’s Fiumicino Airport. Monday June 3rd will be dedicated to road transfer via motorway A1 (Roma- exit Orte), then superhighway E-45 until Perugia with exit Bosco-Gubbio. Then road n. SS-298 to Gubbio. Time of transfer is about 3 hours. To return time in Rome is planned for Friday 7th according with the participant’s fly schedules. The accommodation in Gubbio is in the medieval part of the town: HOTEL GATTAPONE - Via Ansidei 6 (100 m from Piazza 40 Martiri) Phone : 075-9272489 . www.hotelgattapone.net. Depending on the logistic constraints for each day, lunch will be either carry-on or in restaurants along the itinerary. The restaurants selected for dinner, mostly near the hotel, offer the characteristic regional cuisine. In case of emergency contact one of the excursion leaders: Marco Menichetti – handy (+39) 3356373022 – home in Gubbio (+39) 0759221997 Rodolfo Coccioni – handy (+39) 3473520122 Delphine Desmares – handy (+33) 144276228 In any case the emergency telephone numbers in Italy are: 118 - Sanitary Emergency 112 – Carabinieri 113 – Polizia Along the field trip itinerary the closer hospitals are localized at: Gubbio - loc. Branca - phone 075 9270801 Cagli - Via. Atanagi 66 – phone: 0721 7921 Ancona – loc. Torrette – phone: 071 5961 1 INDEX Geological and stratigraphic framework of the Umbria-Marche basin……….......... pag.3 June 4th – The Gubbio area pag.7 STOP 1.1 – The Cretaceous stratigraphy of the Umbria-Marche basin and the Cretaceous pelagic succession of the Vispi Quarry………………….. pag.10 STOP 1.2 - The Bonarelli level (OAE 2) at Contessa………………………………. pag.14 STOP 1.3 - The Cretaceous/Paleogene boundary of the Contessa Valley………… pag.24 STOP 1.4 - The Bottaccione Gorge and the C34n/C33r reversal boundary………... pag.25 STOP 1.5 - The inoceramid extinction at Bottaccione……………………………... pag.29 STOP 1.6 - The K/Pg boundary at Bottaccione…………………………………….. pag.32 June 5th The Monte Nerone-Monte Catria area pag.35 STOP 2.1 – The Jurassic/Cretaceous boundary at Bosso …………………………. pag.36 STOP 2.2 – The Aptian-Albian Fucoid Marls and the late Aptian- middle Albian organic-rich layers at Poggio le Guaine……………………………… pag.39 STOP 2.3 – The Maiolica-Fucoid Marls transition and the Selli Level (OAE 1a) at Gorgo a Cerbara……………………………………………………… pag.41 STOP 2.4 – The Furlo anticline - SW limb - Lower quarry - The UM basin from Jurassic to Cretaceous………...………………………………………. pag.46 STOP 2.5 – The Furlo anticline - SW limb - Upper Quarry - Cretaceous stratigraphy –Bonarelli Level – calcareous turbidites and slumps…… pag.48 June 6th - The Monte Conero area pag.51 STOP 3.1 – The Cretaceous Scaglia and the K/Pg boundary at Monte Conero……. pag.52 STOP 3.2 – The GSSP for the Eocene/Oligocene boundary at Massignano……….. pag.54 STOP 3.3. – Panoramic view of the Cretaceous Scaglia in the eastern limb of Monte Conero anticline pag.56 References………………………………………………………………………….. pag.57 2 Geology and stratigraphic framework of the Umbria-Marche Apennines . The UMA form the southern sector of the Northern Apennines, part of the peri- Mediterranean system of Alpine chains formed as a result of differential movements between Africa andEurope plate. The area has been affected by at least three main tectonic phases: an extensional phase in the Mesozoic, compressional in the Neogene and, an extensional phase in the Umbria sector from Late Miocene and Pleistocene onward. The Umbria-Marche sedimentary basin formed in the late Triassic in a passive continental margin of the southern Tethys Ocean. Its over 3000 m thick stratigraphic succession records the thermal and mechanical subsidence history from the Jurassic carbonate platforms to the pelagic realm of the Paleogene, while its upper part consists of Neogene terrigenous clastics that accumulated in a migratory foredeep system reflecting the encroachment of the Apenninic deformation and sedimentation patterns into the Adriatic Foreland. The extensional regime triggered by the opening of the Tethys Ocean in the Late Triassic–Early Jurassic is recorded in the stratigraphic succession by a change in the facies type and thickness. The subsequent deposition of evaporites and dolomites in the Upper Triassic was followed by the formation of a carbonate platform in the Early Jurassic. Throughout the Early–Middle Jurassic, the opening of the Alpine Tethys Ocean led to the separation of the persistent carbonate platform (Central Apennines, Latium–Abruzzi region), where the sedimentation rates compensated for the syn-rift subsidence, from the pelagic domain (Northern Apennines, Umbro-Marchean region) by a slope-to-basin transitional domain. The UM pelagic basin was subdivided into structural highs and deeper basinal areas of varying thicknesses and facies bounded by Jurassic faults. The extensional phase ended during the Early Cretaceous when the deposition of the Maiolica Fm. homogenized the lithological facies while maintaining the differences in the bathymetry between the former structural highs and lows (Fig3). Sedimentation in the area became homogeneous following the deposition of the Fucoid Marls Fm. in the early Aptian evolving towards hemipelagic lithotypes characterized by carbonates and marls with an abundance of chert during the Cretaceous and Paleogene. The Cretaceous UMA sequence is lithologically subdivided into several discrete formations and members on the basis of colour changes and carbonate content fluctuation along with the presence or absence of chert and black shales. The following sequence spanning a thickness of about 750 m can be recognized: Maiolica (late Tithonian – early Aptian), Fucoid Marls (early Aptian – latest Albian), Scaglia Bianca (latest Albian - earliest Turonian) and Scaglia Rossa (earliest Turonian – early Lutetian). Although characterized by homogeneous sedimentation during the Cretaceous, the UM pelagic basin records several tectono-sedimentary events. Slumps are common, especially in correspondence to Jurassic faults reactivated in the Aptian and Turonian and in the Late Cretaceous. Carbonate turbidites composed exclusively of foraminifera are very common in the whole UM basin, but are particularly abundant in the Late Cretaceous. Convergent orogenic activity in the Alps began in the Late Cretaceous (Fig. 4) while the Northern Apennines foreland fold-and-thrust belt developed since the Late Oligocene with the convergence and subsequent subduction of the Adriatic microplate under the Corsica- Sardinia block. The latter was controlled by the opening of the Liguro-Provencal ocean, which caused an ~30° rotation of the Corsica–Sardinia block and was accompanied by the development of the foredeep where proximal turbiditic sediments were deposited. Since this time, the tectonic and sedimentary activity has migrated eastward. In the early Miocene (late Burdigalian–early Langhian), the back-arc extension shifted eastward with the spreading of the Tyrrhenian Sea. The orogenic front has also shifted 3 eastward (possibly related to the subsequent roll-back and retreat of Adriatic lithosphere) with the progressive development of an arcuate thin-skinned fold-and-thrusts belt of NE convexity with the deformation of the Adriatic foreland against the foredeeps. The latter give good timing of the deformation, it’s rate and the evolutional history of the tectonic-sedimentary events for all of the Northern Apennines. The turbiditic deposits of the Miocene Umbro-Marchean and Romagnan foredeep are arranged in a typical tripartite suite, with basal prototurbiditic marls, a thick marly arenaceous orthoturbiditic sequence and capping cataturbiditic marls. The distribution of these intervals reflects the migration pattern of the foredeep system, which accompanied the migration of the orogenic paroxysm toward the Adriatic foreland characterized by propagating detachment tectonics in active foredeep segments. The synsedimentary character of this process is recorded by the distribution of key levels and slump zones. The depocenter migration of the foredeep system reconstructed for the early to middle Miocene amounts to about 10 km/Ma, increasing to 20 km/Ma during the late Miocene through Pleistocene. The UMA tectonics since the middle-late Miocene and up to the Pleistocene, were characterized by coeval occurrence of shortening in the foreland and extension in the hinterland. This Tyrrhenian Sea related extension, continued through