Volume n° 1 - from PR01 to B15 32nd INTERNATIONAL GEOLOGICAL CONGRESS GEOLOGICAL STRUCTURE OF THE ROMANIAN CARPATHIANS Leader: M. Sandulescu Associate Leader: R. Dimitrescu Field Trip Guide Book - B12 Field Trip Florence - Italy August 20-28, 2004 Pre-Congress B12 B12_ copertina_R_OK C 28-05-2004, 19:17:12 The scientific content of this guide is under the total responsibility of the Authors Published by: APAT – Italian Agency for the Environmental Protection and Technical Services - Via Vitaliano Brancati, 48 - 00144 Roma - Italy Series Editors: Luca Guerrieri, Irene Rischia and Leonello Serva (APAT, Roma) English Desk-copy Editors: Paul Mazza (Università di Firenze), Jessica Ann Thonn (Università di Firenze), Nathalie Marléne Adams (Università di Firenze), Miriam Friedman (Università di Firenze), Kate Eadie (Freelance indipendent professional) Field Trip Committee: Leonello Serva (APAT, Roma), Alessandro Michetti (Università dell’Insubria, Como), Giulio Pavia (Università di Torino), Raffaele Pignone (Servizio Geologico Regione Emilia-Romagna, Bologna) and Riccardo Polino (CNR, Torino) Acknowledgments: The 32nd IGC Organizing Committee is grateful to Roberto Pompili and Elisa Brustia (APAT, Roma) for their collaboration in editing. Graphic project: Full snc - Firenze Layout and press: Lito Terrazzi srl - Firenze B12_ copertina_R_OK D 24-05-2004, 15:38:15 Volume n° 1 - from PR01 to B15 32nd INTERNATIONAL GEOLOGICAL CONGRESS GEOLOGICAL STRUCTURE OF THE ROMANIAN CARPATHIANS AUTHORS: M. Sandulescu (University of Bucharest - Rumania), R. Dimitrescu (Romanian Academy, Bucharest - Rumania) Florence - Italy August 20-28, 2004 Pre-Congress B12 B12_R_OK A 24-05-2004, 15:42:10 B12_R_OK B 24-05-2004, 15:42:12 GEOLOGICAL STRUCTURE OF THE ROMANIAN CARPATHIANS B12 Leader: M. Sandulescu Associate Leader: R. Dimitrescu Introduction Geology of the South Carpathians in the Danube The fieldtrip “Geological Structure of the Romanian Gorges (Romanian Bank) by Pop et al., 1997. Carpathians” strives to cross the major tectonic units of this segment of the Tethyan Chains, with the General Geological Setting purpose of presenting a general approach to the tec- General Structure and Evolution of the Romanian tonic and paleogeographic (paleotectonic) problems. Carpathians Knowledge of Carpathian geology allows us to under- (according to Săndulescu, 1980, 1984, 1994) stand the prolongation of the Alps toward the Balkans The Carpathians are a segment of the Tethyan and the Dinarides. In order to accomplish the above- Chains; toward west they join the Alps and toward mentioned tasks during the fieldtrip, a part of the south and south-east the Balkans and the Rhodope. significant geological cross sections in the East and The Carpathian Foreland includes several platforms South Carpathians as well as in the Apuseni Mts will (Scythian, Moesian) or cratons (East European) as be visited. Thus we will examine the tectonic units is- well as the Cimmerian North Dobrogea Orogen sued from the Tethyan Ocean - squeezed in the Main (Figure1). The Carpathian Folded Area is the result Tethyan Suture Zone or obducted on the continental of several tectogenetic events of different ages: Cre- margins – and their deformed continental margins. taceous (generating the Inner Zones named Dacides) In the areas crossed by the fieldtrip geological maps and Miocene (the Outer Zones named Moldavides). and older fieldtrip guidebooks are available. It should Upper Cretaceous and/or Paleogene post-tectogenetic be remembered that in respect to the geological maps covers develop above the Inner Zones. The Pannonian or other guides, in the guidebook proposed here more and the Transylvanian, Neogene molassic depressions or less important differences are possible, determined overlie important parts of the Inner Zones and a part by the progress of our knowledge and/or a better un- of their post-tectogenetic covers. A Neosarmatian-Eo- derstanding of the geological processes. pleistocene molassic asymmetric foredeep develops Geological Map of Romania, scale 1: 200,000, sheets: in front of the Orogen, partly (inner limb) superposed Rădăuti, Topliţa, Piatra Neamţ, Odorhei, Brașov, on its external zones (Figure 1). The Folded Area can Turda, Brad, Deva, Tg. Jiu, Baia de Aramă, Reșiţa. be divided into several major tectonic ensembles: Geological Map of Romania, scale 1: 50,000, sheets: Vatra Dornei, Pojorâta, Câmpulung Moldovenesc, The Main Tethyan Suture Zone (MTS) which Dămuc, Voșlăbeni, Miercurea Ciuc, Brașov, Zărnești, groups together tectonic units constituted by Middle Codlea, Zlatna, Câmpeni, Avram Iancu, Biharia, Brad, Triassic-Middle Jurassic ophiolitic complexes over- Deva, Lupeni, Schela, Tismana, Obârșia Cloșani, lapped by sedimentary formations whose age (Middle Orșova, Reșiţa, Bocșa. and Upper Triassic, Jurassic or Upper Jurassic-Lower The Structure of the East Carpathians (Moldavia- Cretaceous) is different from the age of the ophiolites Maramureș Area) by M. Săndulescu et al., 1981, they cover. The MTS which runs along the Vardar Guide to Excursion B1. Zone (between the European and the Apulian conti- Structural Relations between Flysch and Molasse nental margins) splits – from Beograd toward north (The East Carpathians Model) by M.Săndulescu et or north-west - into two branches: the South Pan- al., 1981, Guide to Excursion A5. nonian (separating the Apulian microplate from the The Structure of the Apuseni Mountains by M.Bleahu Fore-Apulian one) and the Transylvanidian-Pienidian et al., 1981, Guide to Excursion B3. (situated between the European and the Fore-Apulian Metamorphosed Paleozoic in the South Carpathians margins) (Figure2). and Its Relations with the Pre-Paleozoic Basement by PR01 to B15 n° 1 - from Volume H.Kräutner et al., 1981, Guide to Excursion A1. The Fore-Apulian Microcontinent (FAM) is situ- The Structure of the South Carpathians (Mehedinţi- ated on the opposite side with respect to the European Banat Area) by S.Năstăseanu et al., 1981, Guide to margin, considering the MTS a major geotectonic axis Excursion B2. of symmetry of the Tethyan Chains. The FAM groups Excursion to South Carpathians, Apuseni Mountains together the Austroalpine, the Central West Carpathi- and Transylvanian Basin. Description of stops by ans and the North Apusenide units (Figure 1), as well Berza et al., 1994 ALCAPA II. as the units covered by the Pannonian Depression 3 - B12 B12_R_OK 3 24-05-2004, 15:42:32 Leader: M. Sandulescu B12 Volume n° 1 - from PR01 to B15 n° 1 - from Volume B12 - B12_R_OK 4 24-05-2004, 15:42:35 GEOLOGICAL STRUCTURE OF THE ROMANIAN CARPATHIANS B12 Figure 1 - Tectonic Sketch of Romania (acc. to (Figure 1). The cover type of nappes are well devel- Săndulescu, 1994). Carpathian Foreland: 1- East oped in the Flysch Zone of the East Carpathians and European Craton, 2 - Scythian (Sy) and Moesian (Mo) in the Subcarpathians. In the South Carpathians only platforms, 3 - North Dobrogea Orogene. Carpathians: 4 - the Severin Nappe (situated tectonically between the Inner Dacides (Northern Apusenides), 5 - Transylvanides, Getic Nappe and the Danubian) is of this type. 6 - Pienides (5 + 6 - Main Tethyan Suture), 7 - Median Dacides (Crist. - Mesoz. Zone, Getic and Supragetic), 8 - Outer Dacides (Ceahlau- Severin), 9 - Marginal Dacides Geotectonic History. (Danubian), 10 - Moldavides, 11 - Post - tectogenetic End-Proterozoic (Panafrican) cratonisation is rec- covers, 12 - Neogene Molasse depressions and Foredeep, ognized in the whole Carpathian Foreland and in 13 - Up. Cret.- Paleoc. magmatic arcs, 14 - Neogene the Carpathian Orogen as relics. This huge cratonic magmatic arcs, 15 - thrust - sheets, 16 - faults. area, preserved actually in the East European Craton, (Figure 2). was split south and west of the former within the The European Continental Margin (ECM) groups Paleozoic mobile areas. The folded basement of the together the main part of the East Carpathians (the Pi- Scythian Platform proceeds from one of these, while enides belong to the MTS) and the South Carpathians. the Paleozoic metamorphic series of the Carpathians There are two basic types of units: basement shearing comes from another branch. Within these branches, nappes and cover nappes. The first type is built up of remnants of Paleozoic oceanic crust-bearing domains Figure 2 - The major Tethyan sutures and continental crystalline formations (metamorphics and sometimes areas in the Carpathian realm (post- tectonic covers is not acid and/or intermediate granitoids) and their normal shown) (acc. to Săndulescu, 1987). 1 a - Inner Dacides, PR01 to B15 n° 1 - from Volume sedimentary envelope (sedimented on the continental 1/2 - Bükk Unit and correlative units, 2 - Major Tethyan margin). This type of unit, which developed in the Suture (Vardar, South Pannonian, Transylvanides, FAM too, constitute the Central East Carpathians Pienides etc), 3 - Măgura Group (belonging to the (the Crystalline-Mesozoic Zone excepting the Tran- suture, 4 - Median Dacides (Central East - Carpathians, sylvanian nappes which are obducted from the MTS Getic & Supragetic nappes), 5 - Outer Dacides (Ceahl u - Severin), 6 - Marginal Dacides (Danubian), - Figure 1,2), its correspondent in the South Carpathi- ă 7 - Moldavides. Bc - Bucharest, Be - Beograd, Bd - ans (Getic-Supragetic ensemble) and the Danubian Budapest, K - Krakow, W - Wien. 5 - B12 B12_R_OK 5 24-05-2004, 15:42:43 Leader: M. Sandulescu B12 Figure 3 - Palinspastic sketches of the Carpathians and their Foreland during the Mesozoic and Paleogene. 1 - Tethyan oceanic crust, 2 - Thinned