Tectonic evolution and paleogeography of Europe P. O. Yilmaz, I. O. Norton, D. Leary & R. J. Chuchla Exxon Production Research Co, PO Box 2189, Houston, TX 77252-2189, USA ABSTRACT The fourth and final phase, that continues today, is the Alpine orogenic cycle which resulted from convergence of Africa and Europe. Multiple rifting and suturing events through Phanerozoic times amalgamated Europe as we know it today. Our detailed analysis of the crustal blocks, now forming of Europe, during the Cale¬ donian, Hercynian and Alpine orogenies, allowed INTRODUCTION us to understand the influence of these events on the hydrocarbon systems of Europe. To summarize this, we present a series of 11 palaeogeographic maps from Carboniferous to We present a series of palaeogeographic maps Pliocene times. These maps were produced as part which summarizes our understanding of the geo¬ of a project to develop basin-wide models for logic evolution of Europe since Carboniferous regional play element distribution in the major times. These maps were produced as part of an hydrocarbon-producing basins of Europe. Exxon project to develop basin-wide models for Description of the tectonic evolution of regional play element distribution in the major Europe can be divided into four main phases which hydrocarbon-producing basins of Europe. are related to motions between Baltica, North The tectonic evolution of Europe can be divid¬ American/Greenland and Gondwana. The first ed into four main phases which are related to phase culminated in the assembly of Laurussia motions between Baltica, North American/Green¬ (Europe and North America/Greenland) during the land and Gondwana. The first phase involved the Early Palaeozoic Caledonian Orogeny; it was fol¬ formation of Laurussia (Europe and North Ameri¬ lowed by the Carboniferous assembly of Pangea ca/Greenland) during the Early Palaeozoic Cale¬ (Laurussia and Gondwana) during the Hercynian donian Orogeny. The second phase was the orogeny. The third phase, involving rifting and Carboniferous assembly of Pangea (Laurussia and separation of these blocks, started in Permian time. Gondwana) during the Hercynian orogeny. The Yilmaz. P. O., Norton, I. O., Leary, D. & Chuchla. R. J.. 1996. Tectonic evolution and paleogeography of Europe. In. Ziegler. P. A. & Horvath, F. (eds), Peri-Tethys Memoir 2: Structure and Prospects of Alpine Basins and Forelands. Mem. Mus. natn. Hist, nat., 170: 47-60 + Enclosures 1-13. Paris ISBN: 2-85653-507-0. This article includes IS enclosures. Source: 48 P. O. YILMAZ ET AL.. TECTONIC EVOLUTION AND PALEOGEOGRAPHY third phase was dominated by rifting and separa¬ quist Line itself, however, does not mark the edge tion of these blocks, starting in Permian times. The of Baltica; the edge is further outboard, buried fourth and final phase continues today and corre¬ beneath younger cover (Cocks and Fortey, 1982). sponds to the Alpine orogenic cycle which results from convergence of Africa and Europe. Pechora For times younger than Jurassic, relative This is the crust under the Barents Sea and motions of cratonic blocks were determined from includes Svalbard. Genesis of this area is poorly sea floor spreading data in the Atlantic. Motions understood; we assume it to be amalgamated by between Europe and Africa were essentially strike the end of the Caledonian orogeny, but most of this slip from 180 to 110 Ma, then swung round to the block probably consists of older crust. convergent motion which continues today. Pre- Jurassic relative plate motions were determined Laurentia from a combination of palaeomagnetic data and North America and Greenland are Precambri¬ geologic data on the timing of tectonic events. An an cratons that make up the Laurentian block. Like important final constraint was that the derived rela¬ Baltica, Laurentia consists of Archean terranes that tive motions were required to produce a pattern were amalgamated during Precambrian times, cul¬ that was geologically reasonable, i.e. no conver¬ minating in the Grenville orogeny between 800 gent and divergent rates that exceed rates known and 1000 Ma. from global post-Jurassic plate motion rates, and relative motion directions that agreed with the tec¬ Avalonia tonic data. This last constraint is particularly Avalonia consists of southern England, Ireland important in the Hercynian orogeny, which and the northeastern seaboard of North America. It includes significant amounts of strike slip motions. rifted away from Gondwana during the Early Cam¬ brian (550 Ma) and was sutured to Laurentia dur¬ ing the Caledonian orogeny (first collision at 425 Ma, end of orogeny at 405 Ma; McKerrow, 1988). There is not enough reliable palaeomagnetic PALAEOZOIC CRUSTAL BLOCKS data from Avalonia to determine its positions between rifting and collision. A motion path for it was determined by first plotting the positions of Europe, North America and Africa at the start and Palaeozoic crustal blocks, as they were assem¬ end of its motion, then interpolating positions bled in Permian times at the end the Hercynian between these times so that the motion of Avalonia orogeny, are shown in Plate 1. Brief descriptions of was continuous. these blocks are given below. Armorica Baltica Armorica is the name for the western Iberian Baltica, also known as the Russian Platform, Peninsula and also for what is now western and is the Precambrian core of Europe; it consists of northern France. Armorica is separated from the several Archean age blocks that were amalgamated rest of France and Iberia (the Southern European into cratonic Baltica before 1.6 Ga (Zonenshain et Block) by a suture zone of Hercynian age. Struc¬ al., 1990). Baltica is bounded on the west by the tural studies within Armorica indicate that it was Iapetus suture and on the east by the Ural suture. severely deformed during the Hercynian orogeny The northern edge of Baltica we take to be the by its collision with the Southern European Block Timan Belt and its extension along the northern (Matte, 1986), which acted as a solid indentor, coast of Scandinavia. This boundary was reactivat¬ wrapping Armorica around itself. Maximum com¬ ed during the Late Cambrian Fenno-Scandian pression of Armorica was 500 km and the axis of orogeny. The southern boundary is less well maximum deformation forms a line of weakness defined. In Early Palaeozoic time, Baltica faced the along which the Bay of Biscay developed in Late Tomquist Sea to the (present day) south. The Torn- Cretaceous times. Source: PERI-TETHYS MEMOIR 2: ALPINE BASINS AND FORELANDS 49 Southern Europe Dark brown: highlands, considered to be sedi¬ Southern Europe consists of northeastern ment source areas. Iberia, the Balearics, southern France, Corsica and Light brown: lowlands, or zones of sediment Sardinia and probably some of the Palaeozoic bypass. crustal elements involved in the Alps. Like Armor¬ Green: continental, fluvial and lacus¬ ica and Avalonia, this block consists of Pan trine. African affinity crust which rifted off Gondwana Yellow: coastal plain, deltaic to inner during the Early Palaeozoic. shelf. Teal: neritic to shelfal. Rhenohercynian Light blue: basin and slope We interpret the Rhenohercynian zone as a Blue: abyssal sediments on either zone of Caledonian accretion that was the locus of thinned continental or oceanic Devonian extension, as evidenced by the occur¬ crust. rence of bimodal volcanics of Devonian age. Bohemian Massif Pink and red colours distinguish collision- and The Bohemian Massif consists of a Precam- extension-related igneous rocks. The only sedi¬ brian terrane which, according to deep seismic mentary lithology shown is a chevron pattern for data, must be separated from the Bmo-Malopolska evaporites. All active structures are indicated using Block (Suk et al., 1984). standard symbols as shown on the map legends. Dashed lines show some political boundaries, pre¬ Brno-Malopolska sent-day coastlines are in blue and some geograph¬ The Brno-Malopolska Block is composed of ic zones are identified with letter codes. For Precambrian granites and metamorphic rocks. This orientation purposes, some cities are also shown. unit includes the southern Holy Cross Mountains Maps are plotted on an Albers equal area projec¬ area (Malopolska Massif). tion (standard parallels 44° and 67°) with Europe in its present-day position. A 5° present-day lati¬ Moesia tude/longitude grid is included, as are palaeolati- This block is assumed to consist of some Pre¬ tude lines derived from a compilation of cambrian crust that was accreted to southern Balti- palaeomagnetic data. ca during the Early Palaeozoic. Tisza This block includes crust with European affin¬ ity (Royden and Baldi, 1988). It rifted from Europe PALAEOZOIC PALAEOGEOGRAPHY in Jurassic time, then joined Apulia in colliding with Europe during the Alpine orogeny. Tisza's crystalline and Mesozoic rocks outcrop only near Mid-Carboniferous (Namurian, 322 Ma) its eastern and western terminations. The Mid-Carboniferous (Namurian, Ser- pukhovian) map, Plate 2, illustrates collision of PALAEOGEOGRAPHIC MAP FORMAT Armorica and the South-European Block near the end of the Hercynian orogeny. This collisional and magmatic episode was largely ensialic, and result¬ ed in emplacement of abundant synorogenic gran¬ The palaeogeographic maps presented here ites, shown in pink. Widespread orogenic were designed to show depositional environments deformations occurred across northern Europe and using the following colours: Iberia and in the Armorican, Saxothuringian, Source 50 P. O. YILMAZ ET AL.: TECTONIC EVOLUTION AND PALEOGEOGRAPHY Bohemian, Silesian, Massif Central, Ligerian, Cor- accommodated partly by thermal subsidence and sica-Sardinia and Carnic Alps areas. partly by continued subsidence of the relict Continental elastics were deposited in the Variscan foredeep. This basin is known as the Armorican and Saxothuringian basins; linear Southern Permian Basin. Possible dextral shear basins formed within the collision zone. Flysch between Gondwana and Europe created intraconti¬ was deposited in foredeeps on either side of the nental transform systems creating local transten- main orogenic belt. Principal flysch basins are the sional and pull-apart basins. Individually, these Cantabrian Basin in the south, and the Rhenish faults show relatively small displacements. Basin in the north. The Rhenish Basin was eventu¬ Grabens along the faults filled with continental ally Filled to capacity, and by Late Carboniferous elastics. Marine shelf sedimentation continued in time (next time slice) marine connections to this the Apulian area. basin were severed. Upper Permian (Zechstein, 251 Ma) Upper Carboniferous (Westphalian A/B, 306 Ma) In Upper Permian time (Plate 5) a marine con¬ nection was established between the Arctic shelves Hercynian deformation continued into the and the Northern and Southern Permian basins via Late Carboniferous. This final phase of crustal the Arctic-North Atlantic rift system (Ziegler, shortening is sometimes referred to as the Variscan 1988). In the extensive Zechstein inland sea, phase. Plate 3 shows palaeogeography for the glacio-eustatic cycles controlled the accumulation Westphalian A/B stage of the Late Carboniferous. of alternating carbonate and evaporite deposits. Widespread Variscan deformations consist of Late Permian fauna suggest communication thrust- and wrench-faulting, folding, post-tectonic between the Boreal Zechstein seas and the Tethys granite emplacement and the accumulation of thick seas via Dobrudgea. Apart from providing haloki- continental sediments in the developing foredeeps. netically induced structural traps, the Zechstein Marine connections to the North-European fore¬ evaporites are an important seal facies, which seals deep basin, located along the northern flank of the the Rotliegendes sands. Further to the south, on the Hercynian orogenic belt, were cut off as it progres¬ Apulian platform, rifting created basins containing sively filled with elastics. In this basin, thick coal both evaporitic and continental deposits. measures were deposited during Westphalian times. These provide the source for most of the gas found in the Rotliegendes sandstones of the South¬ ern Permian Basin. Sedimentation on the South Apulian shelf was locally disrupted by Variscan MESOZOIC CRUSTAL BLOCKS tectonic events. Crustal blocks involved in the Mesozoic and Lower Permian (Rotliegendes, 254 Ma) Cenozoic Alpine-Carpathian deformation are shown on a Present-Day base map in Plate 6. Europe and Africa remained relatively stable Lower Permian time was dominated by the through this time, although older structural grain collapse of the Hercynian mountain ranges and the was reactivated during the Alpine orogeny. Europe deposition of thick clastic sequences in the area of and Africa are relatively stable plates to which dif¬ their northern foreland basin. The Rotliegendes ferent crustal blocks were amalgamated through (Plate 4) clastic reservoir facies was the first Mesozoic and Cenozoic times. Amalgamation is sequence to be deposited. Sedimentation was Source: PERI-TETHYS MEMOIR 2: ALPINE BASINS AND FORELANDS 51 still going on today with active subduction at the European margin during the Meso-Alpine orogeny Hellenic trench. (Dixon and Dimitriadis, 1984; Sengor, 1984). Iberia The Iberian Block behaved independently of Europe and Africa during the Late Cretaceous and Paleogene (Choukroune et al., 1989; Roure et al., MESOZOIC PALAEOGEOGRAPHY 1989). The cratonic core of the Iberian peninsula consists of Precambrian and Palaeozoic rocks which have undergone Hercynian structuring dur¬ Upper Triassic (Rhaetian, 210 Ma) ing the Late Palaeozoic (Pin, 1990; Franke and Engel, 1986; Ziegler, 1988, 1990). Apulia Plate 7 shows Upper Triassic palaeogeogra- Apulia played a key role in the Alpine- phy. Triassic times were characterized by regional Carpathian deformations (Channell et al., 1979; extension with multidirectional systems of grabens Biju-Duval et al., 1977). The Apulian Block being superimposed on Hercynian structural extends from Italy through the Pannonian area, the trends. This extension, known as the Tethyan rift Adriatic, Greece and further east to Turkey. There event, had a profound influence on hydrocarbon is no known pre-Hercynian crust in Apulia. It plays in the Apulian and Carpathian regions. Shal¬ probably formed as accretionary crust during the low water reefal limestones characterize rifted Hercynian collision of Gondwana with Europe. margins throughout Apulia. Rifting was accompa¬ Apulian crust was extensively affected by subse¬ nied by a widespread extrusive and shallow intru¬ quent Mesozoic rifting, until Jurassic separation sive volcanism, (Dietrich, 1979; Spray et al., from Africa eventually led to formation of the 1984), although individual outcrops are not large Eastern Mediterranean oceanic crust. In Tertiary enough to be shown on Plate 7. Large areas of times, Apulia collided with Europe, initiating the northern Europe were affected by Triassic exten¬ Alpine-Carpathian orogen. During this event, the sion, controlling the subsidence of many basins Apulian Block was shortened and partly subduct¬ (Plate 7). Generally low Triassic sea levels and ed. East-dipping subduction formed the Dinaric narrow rift basins led to highly restricted water belt along the eastern margin of Apulia, and west¬ bodies and the deposition evaporites (e.g. Muschel- dipping subduction formed the Apennine belt kalk, Keuper of northern Europe). During the Tri¬ along its western margin (Royden, 1993; Doglioni, assic, numerous marine connections were 1992; Casero et al., 1990; Moretti and Royden, established between Tethys and the basins of north¬ 1988; Frasheri et al., Anelli et al., this volume). ern Europe, which, since the Lower Triassic, were separated from the Arctic Seas. Tisza and Moesia On the Apulian block, a distinctive platform- Tisza and Moesia were discussed above in the basin palaeogeography was established by Triassic section on Palaeozoic blocks. rifting. Grabens were filled with terrigenous sedi¬ ments, grading upward into pelagic, cherty carbon¬ Sakarya ates. Platforms localized shallow water carbonates Sakarya is a Cimmerian block which rifted off (including reefs) and evaporites. In northern Italy, the northern margin of Gondwana during Late Per¬ Middle Triassic to Carnian volcanics and massive mian to Triassic times and collided with Europe in reefs outcrop in the Dolomites. In the Adriatic and Late Triassic to Liassic times (Sengor, 1984; Sen- Central Apennine areas, shallow water evaporites gor et al., 1984). (e.g. Burano formation) were deposited, while deep-water elastics (e.g. Riva di Solto formation) Rhodope characterized the Northern Apennines and Po Rhodope is part of Europe. It rifted off Europe Basins. Both the Burano and Riva di Solto forma¬ but never strayed very far before colliding with the tions include source-rock facies (Anelli et al., this 52 P. O. YILMAZ ET ALTECTONIC EVOLUTION AND PALEOGEOGRAPH Y volume). During Late Triassic times, possible ini¬ tudes favoured deposition of widespread carbonate tial opening of the Vardar ocean occurred. This platforms, especially on Apulia. In the Brian?on- marked the first formation of post-Hercynian nais area (#4 on Plate 8), rifting caused foundering oceanic crust in the study area (Spray et al., 1984; of the older Middle to Upper Triassic platforms, on Dietrich, 1979). which shallow water carbonates had been deposit¬ In northern Apulia, distinct transverse zones, ed (Rudkiewicz, 1988; Michard and Henry, 1988). following Hercynian trends, were established. In the Helvetic realm, sedimentation was These zones were manifested as a series of flexures dominated by carbonates grading into marly which delimited domains of platform/basin geome¬ sequences (Funk et al., 1987). In Lias and Dogger try. times, sedimentation consisted of mainly shales During Late Triassic times, long-standing (Dauphinois facies). Rapid horizontal facies south-directed subduction of the Palaeo-Tethys changes and wide stratigraphic gaps characterize ocean along the northern margin of the Cimmeria this facies (Masson et al., 1980). Rifting in the blocks terminated with their collision with Europe Eastern Mediterranean resulted in formation of (Sengor, 1984; Sengor et al., 1984). In Europe, oceanic crust in the Antalya area (# 2 on Plate 8; Cimmerian deformations of Late Triassic and Robertson and Dixon, 1984; Yilmaz, 1984). Early Jurassic age is documented by unconformi¬ Along the Cimmerian collision zone (#1 on ties in the Polish Trough, the Northern Po Basin, Plate 8), flysch deposition occurred in Dobrudgea, and in the Italian Dolomites. Crimea and Northern Turkey (Sengor, 1984). Cim¬ Along the African margin, Ladinian to Carn- merian orogenic activity terminated in Early Juras¬ ian age extensional tectonics created half-grabens sic times, as evidenced by intrusion of Middle and pull-apart basins in the High Atlas trough. This Jurassic plutons on both sides of the suture. Effects trend followed an aborted Late Carboniferous to of this event were also felt in the Polish Trough, Permian rift (Cousminer and Manspeizer, 1977). and local inversion occurred in the Donets Trough. During the Late Triassic and Early Jurassic, the The Iberian Meseta was an important source newly created grabens were filled with continental of elastics in the Cantabrian Basin, Lisbon and and evaporitic sediments. Further west in Morocco, Cavalla basins and also the Duero Basin (Wildi, grabens were associated with continental elastics 1983; Ziegler, 1988). Scattered extensional mag- and alkaline volcanism (Wildi, 1983). matism occurred on the Iberian Meseta and also in the Pyrenees area. Along the African margin, tilting and founder¬ ing of fault-blocks occurred mainly during the Early Jurassic (Toarcian, 179 Ma) Sinemurian and thus is slightly older than the time represented on Plate 8 (Favre and Stampfli, 1991). During Early Jurassic times the Tethyan rift system remained active (Biju-Duval et al., 1977; Middle Jurassic (Bathonian, 158.5 Ma) Dewey et al., 1973; Dercourt et al., 1986; Ziegler, 1988, 1990). Plate 8 shows palaeogeography for the Toarcian stage of the Early Jurassic. This was also the time of initiation of opening of the Central The Bathonian map (Plate 9) shows the onset Atlantic between North America and Africa; with of sea floor spreading in the Central Atlantic. This this a sinistral strike-slip regime was established spreading system continued to the north between between Africa and Europe. At this time marine Iberia and Africa and then bifurcated into two connections were reopened between the Arctic branches, one between Apulia and Europe and one Seas and the Tethys Ocean via the Arctic-North between Apulian and Africa. Continuation of the Atlantic rift (Ziegler, 1988). Continued tectonic northern branch past the Tisza and the Pienniny subsidence of the Tethyan and European rift sys¬ area into the Black Sea is speculative; this is based tems, combined with a eustatic sea level rise, open on occurrence of rifting in the Magura Trough and oceanic circulation patterns and low palaeolati- PERI-TETHYS MEMOIR 2: ALPINE BASINS AND FORELANDS 53 Mecsek Zone and provides a mechanism for the arated from Europe in Tithonian times and subse¬ formation of the Transylvanian ophiolites. quently became attached to Apulia before again In the Helvetic domain, sedimentation patterns colliding with Europe in Eocene times. indicate progressive starvation and deepening of the basin: Middle Jurassic manganese oozes are succeeded by Late Jurassic radiolarites, Tithonian Lower Cretaceous (Aptian, 112 Ma) Calpionellid oozes, slump deposits and transported turbiditic calcarenites. In the Tethys area, a global high-stand led to widespread carbonate platform development. Pelagic sediments were deposited in By Mid-Cretaceous times, Atlantic sea floor troughs while shallow water carbonate sedimenta¬ spreading had propagated northward between tion appears to have kept pace with subsidence on Iberia and North America and Iberia started to sep¬ the platforms, continuing the distinctive basin/plat¬ arate from Europe (Plate 10). Mediterranean sea form topography of Apulia. Carbonate platforms in floor spreading was nearly complete. Motions the Dinaric and Friuli areas supplied large amounts between Africa and Europe, which were sinistral of debris into the Belluno Basin (Massari et al., from Jurassic through Early Cretaceous times, 1983). Apulian carbonate platforms reached their changed in Mid-Cretaceous times to progressively maximum extent in Cretaceous time. more convergent, with the convergence direction becoming almost normal to the European margin by Eocene times as the Arctic-North Atlantic opened. This convergence established the Alpine Late Jurassic-Earliest Cretaceous orogeny as well as several other, more localized compressional events. One of these was in the Rhodope area, with congressional deformation We do not have palaeogeographic maps cover¬ and flysch deposition along the southern margin of ing Late Jurassic and earliest Cretaceous times. the Moesian Platform. Compression also occurred Some of the major tectonic events are briefly sum¬ along the eastern margin of Golija and on the marized here. Pelagonian Platform. During Early Cretaceous Late Jurassic to Early Cretaceous tectonic times, Pelagonia collided with Rhodope and development of southern Europe was primarily emplacement of nappes took place in the Hel- controlled by opening of the Central Atlantic lenides and Dinarides. which established a regional sinistral shear In Iberia and the Aquitaine Basin, block tilting between Africa and Europe. Apulia rotated in a associated with extensional tectonics as well as counter-clockwise direction, opening the Mediter¬ halokinetic movements of Triassic evaporites took ranean until Mid-Cretaceous times, when it place during Early Cretaceous times (Le Vot et al., became fixed to Africa (Dewey et al., 1973; this volume). In the Western Alps, collision started Bernoulli and Lemoine, 1980; Biju-Duval et al., during Cenomanian-Early Senonian time due to 1977; Channell et al., 1979). Several ophiolitic subduction of the European margin south or south¬ suites (e.g. Liguride, Piedmont, Transylvanian and east beneath the Apulian margin; this is evidenced Vardar) were formed by these spreading events. by blueschists and eclogites (Debelmas, 1989). The A Late Jurassic subduction zone with calc- suture is seen in the Canavese slices (schistes lus¬ alkaline volcanism and flysch sedimentation tres) and Sesia zone. High pressure metamorphism formed along the Dinaric shelf margin of Apulia associated with the suturing event has been dated (Frasheri et al., this volume). Faunal evidence from at 130 Ma and also 100-80 Ma (Debelmas, 1989). the Mecsek and Villany-Bihor areas on the Tisza Upper Jurassic -Lower Cretaceous ophiolite-bear- platform and the Brian?onnais zone of the Alps ing, highly deformed nappes are overlain by Upper (Roux et al.. 1988) indicates that these areas were Cretaceous relatively undeformed flysch nappes, linked until Tithonian times and but were separated indicating the beginning of European-African com¬ afterwards. This indicates decoupling of the Tisza pression in the Albian. Intra-Apulian deformation block in Tithonian time. We suggest that Tisza sep¬ was localized along pre-existing lines of weakness, 54 P. O. YILMAZ ET AL.: TECTONIC EVOLUTION AND PALEOGEOGRAPHY principally Permo-Triassic grabens. An east-dip- closely linked to eustatic sea level changes. Local ping subduction zone initiated in front of the Golija extensional processes generated important modifi¬ and Pelagonian platforms. During the Late Creta¬ cations in thickness, particularly within the Lower ceous, major tectonic movements affecting the Triassic, Liassic, Kimmeridgian and Aptian series, Austro-Alpine domain, the internal Dinarides.and as well as within the Pyrenean Mid- and Upper the Southern Alps are expressed by a transition Cretaceous deposits. By the early Campanian, sea from flysch sedimentation in the Lombardian and floor spreading ceased in the Bay of Biscay and Julian-Slovenian basins to a pelagic setting in the Iberia began to converge with Europe. In the east¬ Belluno basin and Trento platform (Massari et al., ern Pyrenees, the main deformation was Santonian 1983). and Campanian. The Pyrenean collision front prop¬ In the Apuseni mountains, Albian thrusting agated westward during late Senonian to and folding, along with flysch sedimentation, indi¬ Palaeocene time. cates that the Tisza block collided with or was close to Apulia by Middle Cretaceous times (Burchfiel, 1980). By Late Cretaceous times, large strike-slip movements dominate the Tisza block and North Pannonian part of the Apulian block as CENOZOIC PALAEOGEOGRAPHY the two blocks impinged on the Carpathian embay- ment. This deformation is also expressed in the Eastern Alps by lateral extrusion structures Lower Oligocene (Rupelian, 33.5 Ma) (Ratschbacher et al., 1991). Further to the east, a north-dipping subduction zone, characterized by magmatic activity and back-arc rifting, was estab¬ lished in the present Black Sea (Gorur, 1989). Plate 11 shows palaeogeography for lower Counter-clockwise rotation of Iberia relative Oligocene times. This was a period of intense tec¬ to Europe resulted in sinistral shear along the tonic activity following the collision of the Apulian North Pyrenean fault zone (Galdeano et al., 1989; and European blocks. This collision was the result Choukroune et al., 1989; Roure et al., 1989). of continued convergence between Africa and Oceanic crust developed in the Bay of Biscay fol¬ Europe. The Apulia-Europe collision was diachro¬ lowing early Aptian separation between Galicia nous, starting north of the present-day Adriatic and Bank and Flemish Cap (Dewey et al., 1973; propagating eastward into the Carpathians and Ziegler, 1988, 1990). Rifting movements decreased westward toward the Western Alps. Extensive considerably in the East-Iberian Basin during Cre¬ deformation, metamorphism, plutonic activity and taceous time, with continental to deltaic sandstone deposition of thick flysch and molasse sequences deposition. In addition to the Pyrenean area, shear occurred along the entire deformation front. deformation took place in the Cantabrian Moun¬ In the Alps, initial deformation occurred in the tains of northern Spain and in the Celt-Iberian Piemont, Briangonnais and Valais zones with later Range in central Spain. The nature of this shear involvement of the Ultrahelvetic and locally the was predominantly transtensional and was mani¬ Helvetic domains. Development of the Molasse fested in the form of rifts and pull-apart basins. Basin accompanied this deformation phase Post-rift deposition began during late Aptian- (Ziegler et al., this volume). Northward transgres¬ Albian time. A thick sequence of shallow water, sion of the Tethys sea led to a progressive onlap of interbedded elastics and carbonates accumulated Cenozoic rocks onto the basal Tertiary unconfor¬ on the subsiding Atlantic margin. mity (Roeder and Bachmann, this volume). Local The Late Cretaceous was characterized by the positive features in the foreland persisted until same opposed evolution of a shallow carbonate Oligocene time when the basin deepened rapidly platform in the eastern Iberides and a deep, terrige¬ (Bachmann et al, 1987). Rising sea levels and local nous flysch basin in the western Pyrenees. During restricted circulation provided ideal conditions for Mesozoic times, both on the platforms and in the the accumulation of very rich source-rocks (e.g. basins, the depositional sequence organization was Fish Shales formation in the Molasse Basin). Source: PERI-TETHYS MEMOIR 2: ALPINE BASINS AND FORELANDS 55 Alpine deformation was coeval with orogenic deformation front into the Cantabrian region. Dur¬ activity along the Apennine and Dinaric fronts. Ini¬ ing the Eocene main Pyrenean deformation phase tial deformation of the palaeo-Apennine chain Iberia was sutured to Europe (Roure et al., 1989; started during Oligocene times with thrusting of Chouckroune et al., 1989; Ziegler, 1988, 1990). the Liguride oceanic and flysch units (#2 on Tethys ocean crust subduction continued in Plate 11). Deformation and flysch sedimentation the Alboran-Corsica/Sardinia region (#5 on were controlled by the palaeotectonic framework Plate 11). Back-arc rifting behind this northwest¬ inherited from Mesozoic tectonics. The shape and dipping subduction zone separated the Balearic interrelations of different basins varied as the struc¬ Islands, Kabyl, Alboran and Corsica/Sardinia tural framework became better defined. The Apen¬ blocks from Europe (Tome et al., Vially and Tre- nine depocenters shifted from south to north as molieres, this volume). different structural units deformed. The amount of deformation increases from the north to the south (Bally et al, 1986). This areal distribution of defor¬ Middle Miocene (Serravallian, 10.5 Ma) mation controls trap size and trap integrity (Anelli et al., this volume). During Eo-Oligocene time, the Apulian promontory pushed the North Pannonian and Tisza Miocene Alpine deformation strongly affected blocks into the Pannonian embayment (Plate 11). several parts of the orogenic belt (e.g. Central, Together they “escaped” into this embayment, Western and Southern Alps, Carpathians, Apen¬ which existed as a gap between the buttresses of nines, Plate 12). In the Molasse Basin, with falling the Bohemian Massif to the northwest and the sea levels and increasing influx of elastics from the Moesian platform to the southeast. In this process, rapidly advancing Alpine orogenic front, the basin the North Pannonian and Tisza blocks pushed the shallowed and a thick continental molasse section flysch, which had been deposited in front of the was deposited (Roeder and Bachmann, this vol¬ inner, crystalline part of the Carpathians, over the ume). Carpathian foreland (#1 on Plate 11). The flysch During Middle Miocene time, back-thrusting was folded and thrusted, accommodating at least of the Southern Alps accompanied deformation 200 km of shortening. Loading of the foreland and along the Dolomites (Doglioni, 1991, 1992; a coincident high stand in sea level provided ideal Ziegler et al., this volume). These thrusts involved conditions for the accumulation of widespread, the Apulian Mesozoic platform and raised the very rich Oligocene source-rocks in the region of northern Po area (#3 on Plate 12). In the southern the Carpathian fold-and-thrust belt (e.g. Dysodilic Po area, local emergence and evaporite deposition and Menilitic shales; see Bessereau et al., Dicea, (e.g. Gessosso Solfifera formation) occurred. this volume). Active west-dipping subduction in the Apennine Compressional deformation of the Alps and region and development of an east-facing foredeep their foreland was contemporaneous with the evo¬ took place, recorded by the Macigno flysch (Anelli lution of the intracratonic Rhine, Bresse, and et al., this volume). Flysch sedimentation from Rhone rifts (Ziegler, 1987, 1990; Ziegler and both the Apennine and Albanian accretionary com¬ Roure, this volume). A pulse of volcanism may plexes created the Po/Adriatic basin as a bivergent have triggered extension in the Rhine Graben dur¬ foredeep area. The main thrusting event in the ing the late Eocene (#4 on Plate 11). By late Apennines occurred during the Miocene. These Eocene-early Oligocene times, a marine connec¬ thrusts utilized Triassic evaporite layers as detach¬ tion was established between the Alpine foredeep ment surfaces (D'Argenio et al., 1980, Boccaletti and the North Sea via the Rhine Graben in which and Coli, 1982). Tortonian continental and lacus¬ the Fish Shales formation was deposited, the trine sediments, unconformably overlying flysch source-rock for most of the hydrocarbon accumula¬ facies, record this event, thereby constraining the timing of the end of the main deformation phase. tions in this graben. Continued convergence of Iberia with Europe On the east side of the Adriatic, subduction of the relict Tethyan ocean continued along the Albanian caused westward propagation of the Pyrenean 56 P. O. YILMAZ ET AL.: TECTONIC EVOLUTION AND PALEOGEOGRAPHY and Hellenic subduction boundary (#2 on to form the Tellian mountains of Algeria and Plate 12). Tunisia (Wildi, 1983). The Carpathian foredeep expanded over the During the late Tortonian, Calabria rifted from European margin as the deformation front migrated the Corsica and Sardinia block, creating the to the East- and South-Carpathians (#4 on Tyrrhenian Sea as a back-arc rift basin. Plate 12). Rapid advance of the thrust front caused the Oligocene source section to be uplifted and maturation of the rich source facies terminated. Lower Pliocene (3.8 Ma) Therefore, over large areas, Oligocene source- rocks are only mature where they have been struc¬ turally buried in the thrust belt or buried by sediments in the very proximal parts of the fore¬ During Pliocene time, development of ocean deep (Bessereau et al., Ziegler and Roure, this vol¬ crust in the Tyrrhenian Sea was accompanied by ume). Volcanism around the Carpathian arc, related extensive magmatism (Channell and Mareschal, to this phase of deformation, began during the late 1989, #1 on Plate 13). This was synchronous with Oligocene and is thought to be related to the sub¬ Pliocene Apennine nappe emplacement. Shorten¬ duction of highly attenuated European continental ing in the Apennines (75 km in the north. 150 km crust beneath the overriding Carpathians. Back-arc in the south; Bally et al, 1986) was balanced by extension began in the Pannonian basin during this extension in the Tyrrhenian Sea (Doglioni, 1991). time. By the end of the Miocene, deformation had Extension initiated in late Tortonian time in the stopped in all but the Romanian portion of the Apennine hinterland, creating small rift basins Carpathians (#5 on Plate 12). filled with Neogene elastics, sitting piggyback- By early Miocene time, the marine connec¬ style on the thrust belt (Boccaletti and Coli, 1982). tions through the Rhine, Leine, and Eger grabens The Apennine foredeep shifted northwards as the were severed as a result of uplift of the Rhenish Liguride thrust belt was reactivated during the Massif and Massif Central. Tectonism in these Pliocene. The Pliocene section, 9 km thick, con¬ grabens, in which as much as 3 km of continental sists of shallow water fluviatile sediments (#4 on sediments were deposited, continued, as shown by Plate 13). Tertiary biogenic gas plays are found in volcanic activity. this foredeep (Anelli et al., this volume). The dra¬ Corsica/Sardinia and the Kabyl blocks were matic subsidence in this foredeep can not be separated from Europe during the early Miocene explained alone by the topographic load of the (23 to 19 Ma; #1 on Plate 12; Vially and Tre- Apennine thrust sheets (Royden and Kamer, 1984; molieres, this volume). This motion was a primary Royden, 1993). driver for deformation of the Apennines. Fault In the Alps, the most significant deformation blocks formed by rifting in the Valencia Trough is in the Helvetic domain. The deformation front contain the largest oil play found to date in Spain continued to progress to the north, leading to late (Torne et al., this volume). Miocene and early Pliocene folding and thrusting The Late Miocene was characterized by com¬ of the Jura Mountains. Peak deformation was dur¬ pression along the southeastern margin of Iberia in ing the latest Pliocene. The thrust decollement in the Prebetic fold belt and in portions of the the Jura is located in the Triassic evaporite section Balearic Islands. Westward escape of the Alboran which continues to the south under the Molasse Block opened the North Algerian Basin in its Basin and eventually under the Alps. The Molasse wake. The Alboran Block collided with the south¬ Basin was carried passively to the north (as a eastern margin of Iberia and the northwestern mar¬ “piggy-back" basin) during this part of its history gin of Africa during the late Oligocene/early (Philippe et al., Ziegler et al., this volume). By the Miocene. Extensive flysch basins mark this end of Tertiary times an approximately 5 km thick Betic/Rif deformation front (the Numidian flysch section of synorogenic elastics had accumulated in of Wildi, 1983; Ziegler, 1988). The Kabyl block this basin. escaped southwards and collided with North Africa Deformation continued in the outermost East- and South-Carpathians. Extremely rapid subsi- Source: