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Berichte des Forschungszentrums :oich •; 2684 ISSN 0366-0885 Internationales Büro Jü1-2684 D 188 (Diss. Freie Universität Berlin)

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® Geol ~ i n

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®IOilIS510S Matarangas

Zusammenfassung

Die Nordsporaden Insel Skopelos besteht aus folgenden tektonischen Einheiten: I . Von der Pelagonischen Einheit im Zentrum sind nur der oberste Teil der metaklastischen Skiathos - Serie (Ladin Karn) sowie frühdiagenetisch gebildete Dolomite des Nor - Rhat aufgeschlos- sen . DarUber liegt typisches Mesoautochthon : Fe/Ni Laterite und Bauxite der Unterkreide sowie Transgressionskonglomerate des Alb (Vracon) füllen ein Erosionsrelief, gefolgt von Rudistenkalken der Oberkreide und alttertidrem Flysch . Das Mesoautochthon weist eine sehr schwachgradige Metamorphose auf. 2. Die Glossa - Einheit im Nordwestteil der Insel ist von NE auf das Pelagonikum überschoben . Sie besteht aus Phylliten, Kalk- schiefern, Marmoren und Grunsshiefern, die aus Tholeiiten mit MORE Charakter hervorgegangen sind . Nach ihrem Gesteinsbestand und ihrer tektonischen Position wird die Glossa -Einheit als Teil der Eohellenischen Decke gedeutet, Ihre Metamorphose ist alter als die unterkretazische Laterit Bildung. 3. In der Palouki Einheit im Ostteil von Skopelos bilden Ero- sionsreste der Eohellenischen Decke die Unterlage einer schwach- gradig metamorphen Schichtfolge aus einer hemipelagischen Kalk- serie mit klastischen Zwischenlagen (Unterkreide), die nach oben in Rudistenkalke und alttertidren Flysch, also in Schichten mesoautochthonen Charakters ubergeht . Die Palouki - Einheit wurde wahrend der mesohellenischen Orogenese im Eozdn auf die Pelago- nische Einheit Uberschoben . Metamorphose und interne Deformation der Palouki Einheit weisen daraufhin, dagdiese im Eozdn von einem Deckenstapel überlagert wurde. Alle Einheiten weisen Falten mit Achsenrichtungen NNE/SSW, WNW/ ESE und ENE/WSW auf, die erst im Eozan geprdgt wurden . Auch die Richtungen der Klüfte, Bruchstörungen und Photolineationen stimmen in allen Einheiten überein . Ihre Maxima NNW/SSE, NE/SW und NW/SE können mit Vorbehalt auf den Faltenbau bezogen werden. Deutlich jünger sind ENE/WSW verlaufende Elemente, die auf die Nordagaische Störungszone unmittelbar nördlich von Skopelos hin- deuten. Paldogeographisch betrachtet war das Pelagonikum wahrend der Trias Tell einer Karbonat = Plattform am Südwestrand des Tethys - Ozeans, aus dem die Eohellenische Decke abgeleitet wird . Die Pa- louki - Einheit war vermutlich am Ostrand der Pelagonischen Plattform beheimatet.

Abstract The island of Skopelos is composed of the following tectonic units: I . The Pelagonian unit in the central part comprises the upper part of the metaclastic Skiathos series (Ladinian - Carnian) and early diagenetic dolomites (Norian Rhaetian), which are overlain by a typical mesoautochthonous sequence : Fe/Ni laterites and bauxites of Early Cretaceous age and transgressive conglomerates filling in a deep relief . They are covered by Upper Cretaceous nudist limestones and Palaeogene flysch . The Pelagonian rocks had suffered a low grade metamorphism . whereas the Mesoautochthonous II

was metamorphosed merely under very low grade conditions. 2. The Glossa unit in the northwestern part of the island was overthrust from the NE onto the Pelagonian . It consists of phyllit.es, cipolines, marbles and greenschists, which had originated from tholeiites with MORE affinities . According to its rock association and its tectonic position, the Glossa series is interpreted to belong to the Eohellenic nappe . Its low grade metamorphism is older than the Lower Cretaceous laterite formation. 3. Within the Palouki unit of Eastern Skopelos . Eohellenic nappe relics form the base of a low grade metamorphic sequence : Hemipe- lagic limestones with clastic intercalations and Lower Cretaceous fossils grade to Upper Cretaceous rudist limestones and Palaeo- gene flysch, i .e . to typical Mesoautochthonous beds. During the Mesohellenic orogenesis (Eocene), the Palouki unit was thrust upon the Pelagonian unit . Metamorphism and internal deformation of the Palouki unit indicate that it was overthrust itself by a nappe pile during the Eocene. Within all units folds occur with axes in NNE/SSW, WNW/ESE, and ENE/WSW directions, The directions of faults, joints, and photolineations are identical all over the island . The systems with NNW/SSE,NE/SW, and NW/SE may be related to the fold systems mentioned above, whereas fractures in ENE/WSW direction are obviously younger and originated probably in connection with the adjacent North Aegean fracture zone In a palaeogeographical view, the Pelagonian rocks of Skopelos had been part of the Pelagonian platform at the southwestern margin of the Triassic Tethys ocean . The Eohellenic nappe is derived from that ocean itself, whereas the Palouki unit originated probably upon the eastern margin of the Pelagonian pl at f orm .

III

Zusammenfassung l Abstract 1 Contents 111

1. Introduction 1 1 .1 . Aims of the research 1 1 .2 . Bibliographic review on Skopelos 3 1 .3 . General outlines of the Hellenides 6 2. Geological units of Skopelos and their stratigraphy 11 2 .1 . Pelagonian unit 15 21 .1 . Skiathos series 15 2 .1 .1 .1 . Previous work 15 2 .1 .1 .2 . Description of the Skiathos Series 16 2 .1 .1 .2 .1 . Outcrops of Ag . loannis 1 2 .1 .1 .2 .2 . Outcrops of Ag . Paraskevi 22 2 .1 .1 .2 .3 . Skiathos series of nearby areas°comparis ons 25

2 .1 .2 . Pelagonian dolomites 27 2 .1 .2 .1 . Previous work 27 2 .1 .2 .2 . Description of Pelagonian dolomites 23 2 .1 .2 .2 .1 . Stratigraphy 30 2 .1 .2 .2 .2 . Microfacies analysis 32 2 .1 .2 .2 .3 . Interpretation of the depositional environment 36 2 .1 .2 .2 .4 . Ooloffiitization 37 2 .1 .2 .2 .5 . Karstification 40 2 .1 .2 .2 .6 . Pelagonian dolomites . Comparison with occurrences in adjacent areas 41 2 .2 . Glossa unit (Eohellenic nappe) 49 2 .2 .1 . Previous work 49 2 .2 .2 . Petrography and metamorphism 52 2 .2 .3 . Geochemistry 55 2 .2 .4 . Correlation of the Glossa Series with those of adjacent areas 59 2 .2 .5 . Conclusions 61 2 .3 . Mesoautochthonous 62 2 .3 .1 . Cretaceous formation 62 2 .3 .1 .1 . Previous work 63 2 .3 .1 .2 . Description of the Cretaceous formations 64 2 .3 .1 .2 .1 . Fe, Ni ° laterites and bauxites 64 2 .3 .1 .2 .2 . Breccio-conglomerates 75 2 .3 .1 .2 .3 . Quartz schists 79 2 .3 .1 .2 .4 . Upper Cretaceous limestones 31 2 .3 .1 .2 .5 . Upper Cretaceous formations of nearby areas comparisons 07

2 .3 .2 . Flysch 39 2 .3 .2 .1 . Previous work 39 2 .3 .2 .2 . Description 90

2 .4 . Palouki Unit 93 2 .4 .1 . Previous work 93 2 .4 .2 . Description of the Palouki Series 95 2 .4 .2 .1 . Basal magmatites 95 2 .4 .2 .2 . Lower series 93 2 .4 .2 .3 . Upper Cretaceous limestones 100 2 .4 .2 .4 . Flysch 100 2 .4 .3 . Summary 101 3. Structural Geology 103 3 .1 . Major tectonic structure of Skopelos island 103 3 .2 . Tectonic elements 106 3 .2 .1 . Folds 106 3 .2 .2, Fractural systems 111 3 .2 .2 .1 . Faults 111 3 .2 .2 .2 . Joints 114 3 .2 .2 .3 . Photolineations 119 3 .2 .2 .4 . Summary and interpretation 126 4. Palsogeography 123 4 .1 . Pelagonian unit 123 4 .2 . Glossa unit 130 4 .3 . Mesoautochthonous 131 4 .4 . Palouki unit 132 5. - Summary 134 Zusammenfasoung 140

6, References 143

Geological map of Skopelos island 1 . I ntr°oductio n .

1 .1 . Airs of the research In the frame of the project of the Institute of Geology and Mi- ning Exploration (I .G . .E .), Athens, for the Geological Map of Greece to the scale of 1 :50000, I was assigned to carry out the geological mapping of Skopelos island, which belongs to the North Sporades islands (Fig .1). . During this work, along with the infor-

mation drawn from the existing literature on the regional geology of the North Sporades archipelago and the Magnesian peninsula, the necessity of a new interpretation of the. geology of Skopelos island became apparent . Therefore detailed geological mapping to the scale of 1 :25000 was carried out . The necessity of structural investigations and detailed mapping of Skopelos island was also

stressed by a publication & WALLBRECHER (1984), having in view the extremely complicated geological setting and structure of the island.

Eased on the above and after many intensive discussions with Prof . Jacobshagen on the geological problems of the island, and mainly based on his encouragement, I decided to carry out a doc- toral thesis in the area . The interpretation of the geolo g ical structure of Skopelos island was strongly supported by the results of the geological mapping of Skyros island (1 :50000) coin- pleted by JACOBSHAGEN ~ MATARANGAS (1959)...

I believe that the conclusions drawn . by this _work give a modern

stratigraphic results from the metamorphic series, and on geoche-

FORELAND fffg Preapulian Zone [fig Plattenkalk Series WEST HELLENIC NAPPES In Ionian Zone Gavrovo-Tripolitza Phyllite Series Tripoli Unit CENTRAL HELLENIC NAPPIES Pelagonian-Maliac-Lyeian Nappe r Parnass ` `1 Boeotian Serie Pindo s Zone

IJ Basal units of Cyclades complex INTERNAL HELLENIC NAPPES rya Vardar Zone 11 Circum Rhodope belt HINTERLAND Serbo-Macedonian massif r+

~ Tectonic boundaries (observed} Tectonic " (Supposed) 7 Zone boundaries 0 Border

Fi .1 . Tectonic sketch-map of Gre44rr . (,klc(lbsha0eh , 1986 ) mical and petrographical studies . These results, moreover, will have a considerable influence on the geotectonic interpretation of the North Sporades archipelago and the Magnesian peninsula.

1 .2 . Bibliographic review on Skopelos VIRLET (1834) was the first researcher who gave geological information on Skopelos island . In his work "Expedition scientifique de Moree" he mentioned that he had recognized Hippurites in limestones which occur north of the town of Skopelos . Further more, he drew out that old formations occur in the northern part of the island, which he named "Archaean". From the later researchers, PHILIPPSON (1901) described in his fundamental work on the geology of the Aegean islands also many of the various geological formations which occur on Skopelos. These formations are the following, from the younger to the older : a) Micaceous-pelitic, micaceous schists, with intercala-

tions of greenish marbles, b) Cover of semicrystalline limestones with dolomites and rudist shells, c) Platy dark coloured manly rocks which contain fossils, such as foraminifers, Miliolidae and

Haplophragmium . Later scientists gave, from time to time, a lot of information on the geological structure of Skopelos island. Special reference is made here to PAPASTAMATIOU & MARINOS (1938,

1940) who drew out that the island is built up by the following formations : a) Phyllites, which occupy the north-western part of the island, b) Mesozoic series, which consists of dolomites and limestones . This series is developed transgressively on the phyl-

lites, c) Rudist bearing limestones, which overlie the dolomites transgressively and d) Flysch, covering the nudist bearing lime- -4-

stones. RENZ (1955) in his monumental work "Die vorneogene Stratigraphie der normalsedimentaren Formationen Griechenlands" united the S]ciathos schists and the Skopelos schists and accepted the view

of PAPASTAMATIOU & MARINOS (1933 . 1940) with respect to the dis- continuity of the Mesozoic series and the underlying limestones. He also explained that the stratigraphic gap between the limestones and the rudist bearing limestones should be attributed to tectonic activity. PAPASTAMATIOU (1964) briefly described the geological structure of the island . According to him the geological formations which occur in the island, from bottom to top are: a. Schists and phyllites which form the geological basement of Skopelos, have been metamorphosed in various stages and occupy the north-western part of the island, b. Dolomites which overlie the schists and phyllites transgr•essively . On the basis of the presence of small megalodon tides and some microfossils, he concluded that they are of Upper Triassic -

Lower Jurassic age, c. Above the dolomites, Upper Cretaceous formations have been deposited tr'ansgr•essively, which consist of schists, conglomerates and limestones and d. Flysch. Finally he supposed that during Middle - Upper Jurassic after the deposition of dolomites and dolomitic limestones, the area was subaerially exposed and subsequently eroded . On this eroded sur- facethe Upper Cretaceous transgression took place.

GUERNET (1971, 1974) presented a geological outline of Skopelos . in which the geological formations were not different from those described by PAPASTAMATIOU (1964) . This researcher reported that the Palouki unit is overthrust onto the Mesozoic series of Skope-

los, but he supposed it to be of Palaeozoic age, and he placed it geotectonically into the Almopias subzone of the Vardar zone. JACOBSHAGEN carried out important investigations not only of the island, but also in the surrounding regions (see JACOBSHAGEN 1979, 1983, 1986), JACOBSHAGEN et al . (1975 . 1976a, 1976b, 1977a, 1977b, 1978, 1984) . With respect to the geological structure of

Skopelos, he mentioned that the island consists of the following geological formations (from bottom to top) ; 1) Werfenian beds . 2) Triassic-Jurassic dolomites, 3) Mafic volcanic rocks, 4) Upper

Cretaceous limestones and 5) Flysch. With respect to the Palouki unit the latter publications do not agree that it belongs geotectonically to the Almopias subzone but they considered it to constitute a lateral transition to the

Cretaceous formations of the island, which belong to the Pelago- nian zone (Pig .1) . From a tectonic point of view . they believed that this cross folded area of the North Sporades with axes in NE

and NNW direction lies in the interior of the central Aegean ore- genic belt, which has a narrow radius of curvature . The formation of this belt occurred at the end of the Eocene, as deducted from stratigraphic and radiometric ages (JACOBSHAGEN & WALLBRECHER, 1984). Further researchers reported briefly on the various geological formations of the North Sporades islands, among them KELEPERTSIS

(1973, 1974), FERENTINOS (1973), WALLBRECHER (1983), HEINITZ, &

RICHTER-HEINITZ (1983) and SCHWANT (1983) .

1,3 . General outlines of the Hellenides RENZ (1910 ; 1940 ; 1955) distinguished various geotectonic zones in Greece . His stratigraphic and tectonic views were cited in the Geological map of Greece, on the scale 1 : 500 .000, (REN2 et al ., 1955) . According to this work RENZ believed that the whole archipelago of the Northern Sporades was part of what he had called the Eastern Hellenic Zone (it comprises the Subpelagonian and the Pelagonian zones sensu AUBOUIN) . Based on the works of

KTENAS (1923 ; 1930) . PAPASTAMATIOU & MARINOS (1938) supposed that the Northern Sporades and Skyros island represent a southward prolongation of the Vardar zone . AUBOUIN (1959) defined the eastern limits of the Pelagonian zone, including only the islands of Skiathos and Skopelos, whereas BRUNN {1960) attributed the whole archipelago of the Northern Sporades to the .Vardar zone AUBOUIN (1973) created, moreover, two groups of isopic zones for the

Greek area based on their miogeo- and eugeosynclinal features (Fig . 2).

SW NE PRF, AF'IILTAN IONIAN GRAVROVO PINDOS PEI.AGONIAN

- ~~~~/~7 '~~~` : ? ~" äd7Y $RRBO MALIAC PAIiCON ALMOPIA MAICEßONIAN PAEONIA PARNASSOS OLYMP08 ~U VARDAR

Fig .2 . Schematic cross section of the Hellenides after AUBOUIN (1973), modified by AUBOUIN & LE PICHON (1977).

The external zones of miogeosynclinal character : comprise: a) The pre-Apulian zone, which he considers with . certainty

autochthonous. b) The Ionian zone, which is overthrust to the SW as a tectonic nappe . It had been detached from its basement within a level of Triassic evaporites. c) The Gavrovo-Tripolitza zone forming an extended nappe in the

area of the Aegean arc . The internal zones, being allochthonous

altogether, consist of eugeosynglinal sequences separated by a miogeosynclinal ridge. a) The Pindos nappe, bearing the Parnassos nappe in central Greece and in north-eastern Peloponesus. b) The group of the Pelagonian and the Subpelagonian nappes which overlie the Bosnian nappe.

c) The Vardar zone which is overthrust on the Pelagonian zone. Finally, the autochthonous Serbo-Macedonian massif which is overthrust on the Vardar zones. JACOBSHAGEN et al . (I978a) introduced a complicated scheme for the geotectonic development of the Hellenides considering the geographical distribution and the stratigraphical position of the ophiolitic complexes and, furthermore, the age and occurence of

the flysch sediments within the different isopic zones . Folding,

nappe movements and regional metamorphism were grouped into four

cycles (Fig . 3): cycle culmination

Neohellenic Miocene Mesohellenic Eocene Eohellenic Lower Cretaceous Cimmerian Middle Jurassic The oldest cycle was confined to the inner regions (Vardar zone).

Hints for a further paroxysm during the Uppermost Cretaceous

®8

West and central conti- Median crystalline nental Greece belt

Inner Hellenic Ophiolitic and sedimentary nappes pappe Maliac nappes Central Hellenic Pelagonian nappes nappes Parnassus p appe Pindus p appe Intermediate units Upper West Hellenic nappes West Hellenic (Ionian and Gavrovo-Tripo- nappes litza series Basal units Lower West Hellenic nappes (Phyllit-Quarzit-serie

Fig .3 . Nappe sequences of the Hellenides (after JACOBSHAGEN, 1986) exist, but they are not distinct (JACOBSHAGEN, 1986).

The alpidic evolution of the Hellenides was initiated and driven by relative movements of the African versus the European plate. At the beginning of the Permo-Triassic sedimentation they were

not yet separated (Pangaea) . But already during the Triassic, several isolated blocks developped, some of which were flooded and separated from each other by a deeper sea . The main impact for the further evolution of the Hellenides was effected by the action of two special micro-plates, namely the Adriatic plate and the Rhodope fragment respectively . Fig . 4 shows the regional distribution of erogenic cycles in the Aegean . To discover the complicated arrangements of nappes within the Hellenides JACOBSHAGEN

(1979) designed a regional sketch and implemented facies and pal-

aeogeographic settings as well (Fig .5) .

- 9-

EKE

a PLATFORMS N ~ikon Iiemipelaeic g overthrust 'r GE Phyllite QuartziteM Feiagonian ME Pelagic 1„0 2 (d,Slibduction, Series , Upper Carbonize- 2_z.-7.13ro0lv0itaza me sohellen ic mt 1dulactsei- rone-Trlas deposition Variscan deforma- -1 =re Apulian Eohell en ic - Fly scn- tions-Series deposition

Fig .4 . Stages of geotectonic evolution of the Hellenides . Cross sections of Northern Greece (after Jacobshagen, 1986) a) Tithonian : Ridges and troughs after the Cimmerian orogenesis of the Circum-Rhodope Belt . During the Middle Jurassic, active rifts had developed within the Almopias trough and probably also in the Pindos-Othrys trough . Subduction of the Almopias trough. b) Hauterivian-Barremian : During the Eohellenic orogenesis, the Vardar zone was folded . The Innerhellenic ophiolites were abducted onto the Pelagonian platform . Ophiolite detritus was deposited ("Boeotian flysch") in front of the ophiolitic nappes as well as in the Vardar zone. c) Oligocene : After the subduction of the Pindos-Othrys trough, a second ophiolite obduction had been initiated by the Mesohellenic orogenesis in Eocene times . During the Oligocene, the Pelagonian platform, bearing the Mesoautochtbonous sequence and some outliers, was sheared off . It was overthrust onto the Gavrovo-Tripo- litza platform together with slabs of metamorphic Orthrys sediments ("blueschist units") . Internal parts of the Pindos zone were accumulated in an accretionary wedge . Sedimentation of the West Hellenic flysch and of the Mesohellenic molasse . Intraconti- nental subduction within the Ionian trough (Phyllite- quartzite and Plattenkalk series). d) Middle Miocene : During the Neohellenic orogenesis, the internal part of the Ionian trough and external areas of the Gavrovo- Tripolitza platform were overthrust onto the external Ionian trough (Plattenkalk series) and the eastern margin of the Apulian platform, dragging slabs of the Phyllite-quartzite series at their base . The Pindos nappe slid onto the West Hellenic nappes by gravity, while the overthrust of the Pelagonian units onto the Tripolitza subzone cintinued . Evolution of complex ndppe structures in the external and the central Hellenides. m Upper Cretaceous ® Lower Cretaceous L Dogger-Maim

~+4 +~ Hinterland --- Foreland Boundaries

Fig . 5 . Regional distribution of the Mesozoic and Cenozoic oroge- neees in the Aegean region (after JACOBSHAGEN, 1986) . -II-

2 . Geological units of Skopelos and their etratigraphy

According to the present geological study and the bibliographic data, three geological units are exposed on Skopelos island (Fig .6), a central unit of Pelagonian character, the slightly metamorphic Glossa unit to the NW and the Palouki unit to theS .

These geological units consist of the following rock sequences:

The central unit includes Pelagonian and esoautochthonous rocks, which consist of the following formations, from bottom to top: 1 . Pelagonian unit. A . Pelagonian sequence. a. Skiathos series, composed of metaclastic rocks with intercalations of recrystallized limestones of Upper Palaeozoic to Carnian age. b. Pelagonian dolomites of Upper Triassic age. B . Mesoautochthonous series. a. Fe-Ni bearing laterites and bauxites. b. Conglomerates of the Cretaceous transgression. c. Upper Cretaceous limestones. d. Flysch. 2 . The Glossa unit (Eohellenic nappe) occupies the north - western part of the island, where the village of the same name lies. It consists of the following rock types: a. Metabasalts. b. Serpentinites. c. Schists. d. Cipolines ......

Palouki unit

Glossa unit

Pelagonian unit

fig .6.Geographica7 situation and the units of Skopelos island . We note that tectonic outliers of this unit were observed in various areas of Skopelos, e .g . at Loutsa, Nisi, Pappou hill, and in the bay of Stafylos . On the whole, the Glossa series is overthrust onto the metaclastic rocks of the Skiathos series and on the Pelagonian dolomites. 3 . The Palouki unit occupies the south - eastern part of Skopelos and consists of the following rock sequence from bottom to top: a . Serpentinites and metabasalts which are in tectonic contact to the flysch of the Pelagonian zone and constitute the basement of the Palouki unit. b,A lower series of thin bedded limestones with intercalations of phyllites and metasandstones, which is of Lower Cretaceous age. c . Upper Cretaceous rudist bearing limestones and d . Flysch. Geomorphologically . Skopelos island shows various hills in its greater part . There are only two higher peaks, the Delphi (662 m) and the Palouki mountains (566 m) . Drainage . basins are rare and small, and only the Stafylos basin, which is the biggest, covers

. ,w-sass se-o ~Pna3 1 3 7san': m.r an area of e .e .iillia . The 1. .d l'VV11,>:i 6A8 V w A+s6sa a u~auand.s charactervnc .na wv ..+wa m by steep slopes . The majority of the shorelines are straight and steep . They form, however, numerous bays, the most important of which are the Skopelos and Glystra bays in the eastern part and Stafylos, Agnonta and Panormos along the sowthwestern coast.

The geological mapping was mainly based----- on str atiy~ 4°ap.~.zm c and tee- tonic data . In the present study it is to reduced to the scale 1: 50 .000 . In the following chapters the stratigraphic setting of the various formations (Fig .7) and the tectonic structure are described in detail and an attempt will be made to sketch the paleogeographic - 14- Flysch

z upper cretaceous limestones.

D 0 ~ Alternations cf thin bedded limestones, schists and meta- < m..N.111 .111.n=• =ftt

~r. .anllo.rrE•=11,mni sandstones. - Serpentinites - Overthrust

D O z Flysch 0 2

U 0 Upper cretaceous limestones.

0 N ia .3 2 Bre cciom conglomerates Fe, Ni-laßerites and bauxites EOHELLEN6C NAPPE

z l•IAWAII IBWnFAW AWE/ u') .~Ir~rr 4 rAwAvAlwsi PelagO iIan dolomites

z o o

RR~ Metaclastic rocks with limestone intercalations. (Skiethos series) o

Fäg .7 . Synthetic stratigraph g c column of Skopelos island . -15-

2 .1 Pelagonian unit

2 .1 .1 . Skiathos series (Upper Palaeozoic to C rnia) The term Skiathos series was created by JACOBSHAGEN & SKALA in 1977 who referred to an Upper Palaeozoic assemblage of metaclastic rocks on the North Sporades mainly occurring on the islands

of Skiathos and Skyros. On Skopelos island, the Skiathos series crops out in a relatively small area, which extends from the southwestern coast between the villages of Elios and Klima towards the north - east up to the

cape of Ag . loannis at Kastri . The series comprises different metaclastic rocks as metasandstones, mica-calcitic, quartzitic and chioritic schists with intercalations of recrystallized lime-

stone beds . The whole series is intensively folded and nearly metamorphosed . Their visible thickness does not exceed 60m.

2 .1 .1 .1 . Previous work All former authors had unified these metaclastic sediments, with the formations of the Glossa unit to one series (Glossa series), which was considered the basement of the Triassic dolomites . Thus VIRLET (1834) believed that the rocks of the Glossa series would

be very old ("Archaic") . PHILLIPSON (1901) pointed out that the Glossa series consists of mica -argillaceous schists with intercalations of green marbles . Especially PAPASTAMATIOU (1964) noted that the Glossa schists, which consist of varicoloured semimeta- morphosed schists, constitute the basement of Skopelos . Although their" age was not yet defined by fossils, he assumed the Glossa schists to be of Upper Palaeozoic age by comparison with schist -16-

formations in other areas.

JACOESHAGEN & SKALA (1977) parallelized these metaclastic sediments with the Glossa series and reported that it consists of chloritic - sericitic and biotitic schists alternating with lime-

stone phyllites and calcitic marbles . In the area of Ag . loannis,

where, according to my opinion, the metaclastic beds belong to the unit of the Pelagonian zone, the same authors observed a downgrading of the metamorphism in relation to the other rocks of

the rest of the Glossa series . They mentioned, furthermore, lith - ological differences, e .g . in the area of Ag . loannis, where they observed phyllites with isolated quartzites and dark coloured

lenses of limestones . In addition JACOBSHAGEN & SKALA (1977) attributed a Werfenian age to reddish and greenish rock layers at Ag . loannis . This predominating type of phyllites had already

been compared with those at Zeta in Euboea by GUERNET (1971). According to the observations mentioned above, they concluded

that the age of this series should be Permian-Lower Triassic as in Skiathos . SCHWANDT (1983) agreed with the views of JACOBSHAGEN

and SKALA that the Glossa series would be pre-Mesozoic and would form the basement of the Triassic dolomites . According to the

parageneses of the petrological types which he defined, he con - sidered the metamorphism of these formations to be of low grade sense WINKLER (1976).

2 .1 .1 .2 . Description of the Skiathos series On Skopelos island, the rocks of the Skiathos series are covered by bushes and by scree . As a result, detailed study is difficult . Two small locations, however, were found, where it was -17-

possible to observe their lithostratigraphical sequence to carry out detailed sampling (Fig .9), and especially to study the relationship between the Skiathos series and the overlying Felago- nian dolomites. These locations are at the north-eastern coast, the chapel of Ag. Ioannis at Kastri and at Ag . Faraskevi, situated at the north- western coast of the island near the village of Elios . On the following pages, a description of the Skiathos rock sequence occuring at these two locations is given.

2 .1 .1 .2 .1 . Outcrops at Ag . Ioannis In this area the coasts are almost perpendicular, due to the existence of a fault in NNW/SSE direction, i .e at right angle to the strike of the Skiathos rocks and the dolomites . This section allows to observe the succession of these beds as well as their contact with the overlying dolomites . The existence, however, of one anticline with an E/W striking axis parallel to the valley near the chapel of Ag . Ioannis, restricts the visible thickness of the Skiathos series which does not exceed 60 m in

this location.

The Upper Palaeozoic to Carnian formations of the Skiathos series consist of metaclastic rocks, with intercalations of recrystal-

lized limestones . These intercalations form either lenses or

interbeds . They can be characterized as phyllites metasandstones and chloritic-calcitic schists.

The. schists appear to form the deeper members of the Skiathos series while near the contact with the overlying dolomites, phyllites predominate over the sandstones and the recrystallized

-18-

limestones . From sea level, where the deeper members occur, to a height of 52 m a monotonous rock succession crops out with chloritic and calcitic schists predominating. The chioritic schists have microcrystalline structure and texture

and are intensively oriented . Their mineralogical paragenesis is:

chlorite ± quartz q muscovite ¢ sericite q albite + leucoxene. Albite is observed in phaenocrystals and has inclusions of calcite and chlorite (neoblasts).

The calcitic schists, consist of fine to medium size elongated crystals of calcite, very fine clastic grains of quartz, and they

are rich in organic material . Also very thin layers of chlorite and muscovite are observed, with grains of an opaque mineral and leucoxene.

From 52 m to 60 m, alternations of phyllites predominate with layers of metasandstones and recrystallized limestones . The latter have a thickness of up to 10 cm, and their colour is black. The phyllites have green to greyish-black colours, are schistose

avtr3 =bgiumAsv.i- r.v-nrsssn9R acaiv.rvrs"eo 1sS .-= . .v.-: r91 i . ...7 WLL\A VLLLLS.Rdii 48iJ .A11VJ0. db14 Vd 'V6idd34 s71.AdJaLi.AdJ4GQ . 1n34d y!r"]4tJ .E.i .d441A Ay% eh{d16111dG41

they show laminated and fine-grained structure and oriented texture with microfolding . The mineralogical paragenesis of phyllites is: sericite-muscovite + quartz + chlorite q albite q calcite.

4- .= ~a.:ar observed 4a,d ~~4 J143' ° ~ as Ji6d.cr ocr~.•w]t6~dl 1s disseminated in the rock, or as concentrated laminae in alternation with laminae of muscovite-sericite . Acid plagioclase (mainly albite) usually forms phenocrystals with or without polysynthetic twinning and

exhibits a slight- sericitization . In much less proportion the minerals turmaline, leucoxene and idiomorph crystalls of hematite occur . These phyllites retain the characteristic features of their sedimentary origin . The original rocks can be characterized

type structure was observed .; so that they

(SPRY, 1959) . .

The metasandstones have a thickness up to IO cm Their colour is

medium size `clastic ..grains of quartz, feldspars (some of them being intensively seriticised), laminae of muscovite and less biotite, as well as of crystals of a calcitic mineral . Also many grains of iron oxides are observed in frameboits . The main matrix seems to be chloritic-quartzitic-sericitic . Feldspars sometimes

occur in perthitic forms . Generally we can conclude that a great part of the clastic material is of volcanic origin . Also in some metasandstones, considerable recrystallization of the connecting material was observed and, to a lesser extent, of the clastic grains . Finally, the orientation of the mineralogical constitu- ents is intense. Near the top of the Skiathos series, at the contact with the o Yper l ~'l SS!.g do l oe.~'.si~we~, the alternation of phyl l i tes and limestone beds becomes more intense . Upward a gradual increase in limestones beds and a decrease in phyllitic and metasandstone beds respectively,is obvious, up to the complete predominance of limestones (Fig .8) . West of the Elia hill, and near the contact with the dolomites, dolomitic intercalations were observed, having a thickness of 25 cm, which are separated from the overlying dolomites by a few centimeters of phyllites . In this stratigraphic ®2 0-

Fig .S . Transition from the metaclastic rocks to the Pelagonian dolomites, Ag . loannis area.

level dense sampling (Fig .9) was carried out in the limestones in

order to identify fossils to define the age of the transition to the dolomites . Because of the recrystallization of the limestone

beds it was, however, not possible to find determinable fossils

except a few fragments of echinoids.

PAPASTAMATIOU (1964) had already noted that in the area of Ag.

loannis he assumed a transgression of the dolomites onto the underlying Glossa schists . Notwithstanding my intense efforts, no transgression could be observed, but on the contrary ; there is a distinct transition from the metaclastics towards the dolomites. The normal transition from the metaclastics to the dolomites is verified biostratigraphically in the area of Ag . Paraskevi (2 .1 .1 .2 .2) . . The geological picture of today in the area (Fig .10) gives the impression of a tectonic contact . This contact was, however, the result of tectonic decollement events during the folding, due to the different behaviour of the rigid dolomitic

-22-

Eig .10 . Secondary tectonic contact of the metaclastic rocks and dolomites, Ag . loannis area. mass and the more plastic metaclastic rocks beneath. The formations of Skiathos series occurring in the greater area of Eastern Greece except the metaclastic rocks and the recrystallized limestone beds, include volcanic rocks as well (KATSIKATSOS 1970 ; KATSIKATSOS,et al . 1982 ; MIGIROS, 1983 ; SIDERIS, 1986 and others) . In Skopelos there are no similar volcanic rocks . This is due to the fact that only a small part of the series crops out on this island.

2 .1 .1 .2 .2 . Outcrops of Ag . Paraskevi

This area lies at the western coast of Skopelos just 500 m north of the recently built Elias village,, with the homonymous church, In this area the visible thickness of the Skiathos series is as small as in the area of kg . Ioannis, reaching about 60 m. The lithologic formations occurring in this area are the same as =23

those in the area of Ag . loannis with the only difference that the metasandstones. seem to have a greater thickness . Almost at the contact, with the overlying dolomites, interbeds of dark

coloured recrystallized limestones occur with a thickness of up to 20 cm (Pig.

Fig .11 . Transitional formation from Skiathos series to Pelago- r.ian : dolomites, Ag . Paraskevi area.

At the coast line near Ag . Paraskevi church, a bed with chaotic structure and a thickness of about 7 m, striking NW/SE, is inter - calated in the metasandstones . This bed lies within the upper members of the Skiathos series and has a non-layered internal structure (Fig .12) . It is interpreted as debris flow (MIDDLETON & HAMPTON, 1973).

Because the morphology of the fiddle Triassic depocenter of the Pelagonian zone is almost unknown and there are only a few out-

Fig .12 . Debris flow, intercalated ~zutasandstones of the Skiathos series, Ag . Paraskevi :area : crops of debris flows 'in .-Greece, we Will not deal here with their

consists of rand= uno.rieni,ed limestone fragments varying in shaood . The matrix of the conglomerates consists of metasandstones . Within the conglomerates there are intercalations of thin bedded limestones . In these limestone interbeds a dense sampling (Fig .9) was carried out in order to find fossils . Due to the recrystallization, it was, however, impossible to determine the microfossils which were observed in many samples . Only in one thin section, from a limestone interbed near the contact with the overlying dolomites in the area of Ag . Paraskevi, certain data were available . These data testify for the first time a Middle-Upper Triassic age of

the upper members of the Skiathos series in Skopelos island (MATARANGAS & SKOURTSIS-CORONEOU, 1989) . The rock in which the -25-

fossils were found was micritic with a number of echirtoid fragments and rare foraminifera (wackestone) . In spite of the intense recrystallization, the presence of the foraminifera Agathammina iranica (ZANINETTI, BRONNIMANN, BOZORGNIA & HUBER) was testified in Skopelos (P1 .I/3,4) . This foraminifera was first recognized in Persian deposits (ZANINETTI et a1 .1972), to which a Norian-Rhaetian age was attributed . ZANINNETTI & BRONNI- MAN (1974) found this fossil again in Triassic formations of Per- sia, the age of which was, however, Ladinian . BRONNIMAN et al. (1974) suggested a higher age (Ladinian or Ladinian-Carnian) fora_ the Triassic formations in which Agathammina iranica was located first . ZANINETTI (1976), in her composite work on the Triassic of Europe and Asia, attributes an Upper Ladinian age to the beds with Agathamina iranica in Persia . Later ALTINER & ZANINETTI (1980) recognized the same fossil in the Ladinian-Carnian formations of Turkey . In Greece, Agathammina iranica was found for the first time in Western Orthrys by COURTIN et al (1982) who propo- sed a Ladinian - Carnian age . CADZICKI & SMITH (1977) came to the same conclusions for Malaysia, and TRIFONOVA (1978) for Bulgaria.

Referring to these results, it is concluded that the upper horizons of the metaclastic rocks of Skopelos, in which Agathammina iranica was found, have a Ladinian-Carnian age ..

2 .1 .1 .2 .3 . Skiathos series of nearby areas - comparisons

The same Ladinian-Carnian age was attributed to relevant formations in the greater area of the Pelagonian zone by different authors . KATSIKATSOS (1970) located foraminiferas in the area of Partheni, Eubosa in a limestone interbed within the pelite-

-26-

sandstone series, which gave an Anisian-Ladinian age for these

formations . IJACOESHACEN & SKALA (1977) described similar forma-

tions on Skiathos island . HARDER et al .(1983) described metaclas-

tic sediments under the name Skiathos series also from Skyros

island . These authors reported that the metaclastic Skiathos series includes lenses of Upper Permian limestones . In the area of Driovouno mountain at Aposkepo of Kastoria PAPANIKOLAOU & ZAMBETAKIS - LEKKAS (1980) found conodonts in samples from a limestone interbed within the metaclastic rocks, which testify to an Anisian-Ladinian age . In the area of Kato Olympos, KATSI- KATSOS et al .(1982) located a conodont microfauna in a limestone interbed within the same formations of Upper Paleozoic to Trias- sic age . These conodonts were characteristic for Ladinian - Lower Carnian . In the area of Atalandi, {gorge of Sgarna), SIDE-RIS (1986) found foraminiferas of Ladinian ® Lower Carnian age in limestones which were included in a volcanosedimentary series. According to all data from Skopelos island as well as from the

9 { 9, .3 .a gr GEdLGA ar GE.d, 3 L Ä ~ LoSdLS IA SA r.t.d LSlESL. tlde w"?c~..Lor of Ear~7tGr li Greece clastic sedimentation ceased during Anisian-Ladinian time and probably up to Lower Carnian . The region was affected by a

volcanic activity, which was followed by carbonate sedimentation on a large platform . Volcanies which are described in many places

the Pelagonian GVd6G within Upper Palaeozoic. Lo Vpper Rir d(1sSSLr

formations, could not be found on Skopelos island . This may be

due to the very small visible thickness of the Skiathos series . 2 .1 .2 . Pelagonian dolomites (Upper Triassic)

The Pelagonian dolomites occupy the central part of the island, with a thickness exceeding ä©® m (Delfi Mnt) . They represent the cover of the Skiathos series, the change of the sedimentation taken within an alternation of calcitic-chloritic schists, phyl-

liter, metasandstones and recrystallized limestones . The Pelago- nian dolomites of Skopelos, which are studied here, belong to the wide-spread Triassic-Jurassic carbonate rocks of the Pelagonian

zone.

2 .1 .2 .1 . Previous work PAPASTAMATIOU & MARINOS (1938) were the first to notice the presence of dolomites in Skopelos . They mentioned small megalo- dontides in the dolomites near the town of Skopelos . Moreover they pointed out that at the Cape of Kavos Kalis these dolomites are unconformably overlain by Upper Cretaceous limestones . PAPAS-

TAMATIOU (1964) gave a short descri p tion of the Pela gonian dolomites of Skopelos and attributed to them an Upper Triassic Lower Jurassic age . He mentioned, furthermore, that brecciated dolomites are frequent within the largest occurrence in the area of Panormos . On the public road Skopelos - Agnonta.s, just before Agnontas, he found small megalodonts, and at the coasts of the same area he observed undefined calcitic algae, which most probably are Gyroporelles . Also in the area of Ditropos he located calcitic algae (most probably Macroporella sp .) and small gastropods . According to the above algal flora, he attributed an Upper Triassic-Lower Jurassic age to the dolomites . He noted, further-

-28-

more, that within the dolomites, diabase rock and basic tuffs occur, which are connected with the overlying bauxites . Finally he estimated that the maximum thickness of the dolomites exceeds 800 m . GUERNET (1971) presented the geographic occurrence of the Pelagonian dolomites in his geological sketch-map of Skopelos . He accepted the age datation of PAPASTAMATIOU (1964).

JACOBSHAGEN & SKALA (1977) noticed that there is a disconformity between the dolomite series and the overlying formations without of course, any tectonic action . They reported that the formations overlying the dolomites are clastic rocks of Cretaceous age, which contain bauxites at the bottom . According to the view of BERNOULLI & LAUBSCHER (1972) and JACOESHAGEN et al (1976), the

rocks which PAPASTAMATIOU (1964) described as basic tuffs constitute a relic of an ophiolitic nappe overthrust during the Lower

Cretaceous.

2 .1 .2 .2 . Description of the Pelagonian dolomites

'Y he 0a] agonI A .-.1 e-44ea r ..---vier vs-e afraat sa. a e+4 nsr Qtr. r.al r.e a.aav J. vaue vaaauan asvavaua a.cO ve..c..~sJy ¶the..aav ~qs ~: :ae.LiC . gr+aa, L. vs v.aawleco O. Their visible thickness exceeds 500 is and they are developed normally over metaclastic formations of the Skiathos series . Their upper members are almost massive and have a whitish to greyish

white colour, while their lower members show a stratified texture

with cyclic alternations of thin whitish, da c..Lnd b l ä ^r{i layers . The thickness of the layers is not constant, but a gradual decrease in the thickness is observed in the dark gray members with a parallel increase in the thickness of the whitish beds (Fig.. 13)

-29-

Fig .13 . Cyclic alternations of whitish, dark gray and black Pelagonian dolomites . Akra Miti.

The dolomites have an almost constant ENE/WSW strike and are folded with a large radius of curvature, the axes striking in the same direction . The beds are tectonically broken, and in many places they have a sucrosic texture . Karst phenomena are

frequent, they will be described. Although the maximum thickness of the Pelagonian dolomites

exceeds 500 . m. 2 p reduced to only a few tens meters . in certain areas, as Akones etc . This must be due to an intense erosion that . took place during the Upper Jurassic -Lower Creta- ceous period . Characteristic is also that the dense pine-tree

forests of the island are developed on the dolomites and the

limits of pine-tree covered areas coincide :with the end of the dolomite outcrops . Thus the macroscopic observation of the dolomites and . their sampling was limited to the coasts, the slopes of the natural sections and the very few roads that exist

on . the ., island . In spite of these difficulties, I effectively used -3 0-

the few dolomite outcrops in natural sections and thus it was

construct the stratigx-aphic column as and microfacies analyses.

During our field work at Skopelos, many macrofossils were recognized in the dolomites, among them small megaiodonts (Fig .14) as

coasts of Stafylos and Panormos . In addition to these macrofossils and the findings of PAPASTAMATIOU (2 .2 .1 .) a dense sampling (Fig .9) was carried out and a few hundreds of thin sections were examined in order to define a biostratigraphic sequence of the

Pelagonian dolomites . In some of them, characteristic microfossils could be recognized . As a result, an accurate definition of the age of the dolomites was carried out.

Fig .14 .Pelagonian dolomites with small megalodon, Pefkias area .

e,31e,

Stafylos area In this area, a microfauna was found in lower members of the dolomites, which consists of abundant foraminifera and fragments

of macrofossils (gastropods, lamellibranchs) . Although the dolomites are recrystallized and therefore the fossils are badly preserved, some of them could be determined Aulotortus friedli KRIS- TAN-TOLMANN (P1 .I/6 .7), also known as Glomospirella friedli and even as Angulodiscus friedli . This fossil is considered to indicate a Norian-Rhaetian age in a number of papers (ZANINETTI,

1977 ; SALAJ et al 1983, and others) . GOCZAN E . et al . {1983) and CATALOV & TRIFONOVA (1985) assumed that Aulotortus friedli

defines a Carnian age, while, according to TRIFONOVA (1972, 1984)

it could be even Anisian.

Limnonari area In samples from the lower dolomite members in the Limnonari area, a fauna of foraminifera and relics of Dasycladaceae were located (MATARANGAS & SKOURTSIS-CORONEOU, 1989) . Among the fora-

~i yti ti ~ s-a ~ Yq ~ '7® .ti w. av-n r+ is 3 3 E~3~'V~dSC'.Hl?NK. .e . (P1. ea'f/ savcvwaaaLLLS 11d LG L. Li d lr\rV .V 11S 6s V ..3 wereYY4A V AulotortusAdd.dA ... .a sinuosus. ••ara .+ .+ .+ . .++ .

1), Aulotortus gaschei KOEHN-ZANINETTI & BRONNIMANN and Aulotor- tus friedli KRISTAN-TOLMANN . According to the literature, the above fossils indicate a Norian - Rhaetian age.

Pefkias area In the greater area of Pefkias hill, a detailed sampling (Fig .9)

was carried out within the dolomites just beneath the conglomerates of the Cretaceous transgression . Especially in thin sections from samples taken exactly at the contact of the dolomites with

the overlying conglomerates, the .,. following . foraminifera were. recognized :

-32-

Aulotortus cf. friedli KRISTAN-TOLLMANN . Earlandia tir2tinniformis MISIC . Angulodiscus of . communis KRISTAN . Moreover, gastropod and ostracod fragments were observed, as well as megalodonts . These fossils define a Norian--Rhaetian age. On the basis of the fossils found and recognized in all these areas (Stafylos, Limnonari, Pefkias), and in combination with the age of metaclastic formations beneath the dolomites (Ladinian- Carnian), a Norian-Rhaetian age can be attributed at least to the main parts of the Pelagonian dolomites on Skopelos island . This does, of course, not exclude the possibility that dolomite deposition had already started during the Carnian.

2 .1 .2 .2 .2 . Microfacies analysis The microfacies analyses of the dolomites, based on the field work and the study of samples in laboratory . After a study of about a hundred thin sections, six microfacies were determined. The greatest variety of these microfacies was observed at the

aao4-an rt~w~~- r.rr 4r1-n a 4®7 ar.r7 ra~ Lf.^.ri~£-~~ I iA .J 44LL lt kJ ...EB 4 5JS 4itG> SiJd.6Stl ..dp V14 the4dtV hill of .1 bLi 4NS p whichiYlib Vd6 liesb V .::N near the bay of Limnonari . A brief description of these microfacies will follow here:

Microfacies 1 ; Algal (Blue-green algae), thinly laminated dolomite with fenestral fabric . It is a biolithite according to FOLK

n E M r (1959, v. bindstone v^ vrl~.Tii`i .-al e (1962) . a.~n^ver ~ t the algae, the presence of fossils is very rare . Very few foraminifera were observed (Involutinidae) and slightly more abundant ostracods.

Fenestral voids (TEBBUTT et al . 1965) (Pl .11/i) are reported as "birds eye or stromatactis" structures in the early North Ameri- -33-

can terminology . According to SHINN (1983) they are partly simi-

lar to the shrinkage pores, or with the loferites defined by

FISCHER (1964) in the Austrian Alps . The term loferite is com-

monly used for calcitic beds that show an abundance of fenestral

voids (FLUGEL, 1982).

In this facies the fenestral voids have a subparallel to irregu-

lar shape and are usually filled by geopetalic internal sediment.

This sediment is micritic, small peloids are observed in it with

a reversed graded bedding (P1 .11/1) . In some samples the internal

sediment consists of crystal silt (PI .III/2), which may point to

a diagenetic derivation by erosion of a preexisting dolosparite.

Finally the fenestral voids were filled by a xenotopic to hypi-

diotopic dolospartic cement (see also FRIEDMAN, 1965).

Characteristic is the presence of mud cracks . In certain samples

cracks were observed at the algal laminae (P1 .11/2) which

occurred before the deposition of the internal sediment . This

suggests that the lithification took place in an earlier diage-

neticV stage . In addition, a few idiomorphic prismatic crystals of

dolosparite were observed, which must have been derived from the

dissolution of evaporites (FRIEDMAN & RADKE . 1979).

The described characteristics of this microfacies (fenestral

voids, mud cracks, very few fossils, crystal silt etc .) indicate

an intertidal environment of deposition (FLUGEL . 1982) . It can be

attributed to SMF 20 (SMF=Standard microfacies) and to facies zone FZ 9, respectively, according to WILSON (1975) and FLUGEL

(1972).

3icrof.acieB 2 . Dolobiopelmicrosparite to dolopelpseudosparite with abundant marine fossils (P1 .111/1) . It consists of peloids -34-

and marine fossils such as rare foraminifera (Trocholina sp .),

Thaumatoporella, ostracods, echinoid fragments and pelecypods

(Megalodon) . The main matrix shows its initial micritic texture

only in very few places . It is mainly microsparitic to pseudo-

sparitic and has a thrombolite structure . The pelecypods are

micriticized in their periphery, while in their interior dolospa-

rite is developed with an increasing size of crystals toward

their center.

This microfacies can be attributed to SMF 16 and to the facies

zone FZ 7 or 8, according to WILSON {1975) . Thus, the environment

of deposition can be characterized as low energy subtidal.

Microfacies 3 : Dolobiomicrite (wackestone-packstone) with fenes-

tral fabric and a variety of marine fossils, like pelecypods,

gastropods, foraminifera (mainly Aulofortus sp .), algae, and

ostracods.

The fenestral voids have irregular shape . Internal sediment was

seldomly observed, cqntaining microclasts or peloids which show a reverse graded bedding . Dolosparitic cement with a characteristic zonal structure is either associated with the internal sediment or it is developed directly on the walls of the voids which are filled with clear dolosparite crystals of mosaic type . The main matrix is micritic to microsparitic.

According to the characteristic features of this microfacies, the environment of deposition is characterized as shallow subtidal to intertidal with low energy and most probably with periods of subaerial exposure (FLUGEL, 1982).

icrofaci s .. .4 : Spongiostrome bindstone . It is characterized by algal laminations which form an irregular anastomosing fabric . -35-

The algae form tufts which are indicated by the branched arrangement of the fenestral voids in the interior of the rocks . The sediment has a thrombolite structure . Very few fossils were observed, like foraminifera (Involutinidae) and very rare sphae-

rulites with length-slow chalcedony . The observed dolomite crystals with rosette form must be related to dolomitized evaporites

(anhydrite, P1 .11/3). Finally this microfacies can be attributed to SMF 21 and to

facies zone FZ 8 . The environment of deposition is characterized as intertidal.

Microfacies 5 : Thinly laminated dolomicrosparite, unfossiliferous (P1 .II/5) . The thin laminae of dolomicrosparite are intercalated with thin dark coloured bituminous convergent laminae . Most probably, they are the result of algal activity (cryptalgal fabric). This microfacies is attributed, like the previous one, to facies

zone FZ 8 . Thus the environment of deposition would be inter- to supratidal.

Microfacies 6 : Homogenous dolomicrosparite (P1 .111/3), unfos si l i- ferous and without lamination . Dolosparitic microveins were observed, which penetrate the rock . The microveins must have been formed in a late diagenetic or metamorphic stage . The primary micritic texture of the rock and the absence of fossils suggest an inter- to supratidal, hypersal i ne and low energy environment of deposition . This microfacies is attributed to SMF 23 and to the facies zone FZ 8 or 9.

In one thin section of a sample taken at Limnonari, very close to the location where microfacies 3 was recognized, coexistence of

two different microfacies was observed . One part is characterized by the presence of blue- green algae and fenestral fabrics . This corresponds to a very shallow environment of deposition (P1 .2). The other part is characterized by the presence of radiolaria and sponge spicules in a micritic matrix (wackestone) which suggests an open marine environment of deposition (P1 .111/6) . The relations between the above two facies were not possible to be determined by the study of this sample . Nevertheless, the following hypothesis can be formulated about this coexistence . The Upper Triassic - Lower Jurassic carbonate platform there might have been interrupted by deep channels or troughs, thus deposition of shallow and deep marine sediments took place synchronously in neighboring areas . With the aid of marine currents or more probably storm events, material from the deeper open sea could have been transported into the shallow areas and, vice versa, gravels from shallow areas could have been inferred into the deeper ones. Similar phenomena of coexisting microfacies having different

ßY'1i]'9 r171 71i714- rs-F r3®r%^,4i• i riat Y.Yewc s~n$®rä b%%7 kT TTC_rT l1 ©F!1 -~ fr J-bye, +-. ;bv dA V ;6übVbZ4 A. 4SV$d V SJA bS V Ld, YP V d V b ;ViV ..i d]JVUb1A3 % iJVJ/ %A %, ;c Pantocrator limestone of Korfou island.

2 .1 .2 .2 .3 . Interpretation of the depositional environment The microfacies analysis of the dolomites in places where the

primary sedimentary structures are preserved, indicates that they were deposited in an environment characterized by a carbonate platform in a supra-inter-subtidal area with cyclic sedimentation . This type of carbonate deposition during Upper Triassic

Jurassic characterizes almost the whole southern continental margin of Tethys and correlates with that presently developed on a continental margin, like at the Florida - Bahamas - Blake pla-

teau, according to BERNOULLI & LAUBSCHER {1972), BERNOULLI & JEN-

KYNS (1974), VARTI-MATARANGAS & MATARANGAS (1990).

Specifically the microfacies analysis shows that the Pelagonian

dolomites of Skopelos are deposits of a very shallow restricted

sea (lagoon) with a tidal depositional environment . Alternating

deposits of subtidal to inter- or supratidal dolomites were obse-

rved, all of them showing a cyclic character in their deposition.

Loferitic stromatolitic forms of dolomites with laminated texture

and fenestral voids with internal sediments predominate in inter-

to supratidal environments . The fragmentation of the algal lami-

nae, which took place before the deposition of the internal sedi-

ments, indicates lithification in a very early diagenetic stage.

The presence of crystal silt, which usually follows earlier

stages of cementation, and of tepee structures (P1 .II/4) very

probably indicate phases of subaerial exposure of the lithified or semilithified sediments . Similar facies and depositional environments (Upper Triassic-Lower Jurassic loferitic cycles) have e .g . been defined in the southwestern periphery of the Pelagonian platform (BACHMANN & RISCH . 3979), in the area of Parnassos . in the Gerania Mountains, at Trapezona, at Didyma/Argolis (RICHTER &

EUCHTBAUER . 1981 ; RICHTER & VARTI-MATARANGAS, 1988 ; VARTI-

MATARANGAS & MATARANGAS, 1990) and at Hydra (SCHAFER & SENOWBARI-

BARYAN, 1982).

2 .1 .2.2 .4 . Bolomitiza .tion

One of the main diagenetic events of the Pelagonian carbonate series is the almost complete dolomitization which took place w 38-

after early diagenetic lithification, cementation (three facies),

micritization, compaction, recrystallization and fracturing.

The great variety of textural characteristics of the dolomites

(very fine to coarse grained), the good preservation of the sedi-

mentary structures and of the fossils in some cases, the determi-

nations of the environment of deposition as well as the geologi-

cal history of the Upper Triassic-Lower Jurassic carbonate plat-

form, lead to some conclusions in respect to the reasons and the

time of dolomitization . Dolomitization developed in different

stages during the evolution of the carbonate platform and with

different mechanisms . At the areas of Limnonari Pefkias, where

the original textures are preserved, we know that the environment

of deposition was a low energy shallow sea with alternations of

humid and dry climate . Dolomitization took place there not only

at the intertidal zone, but also at the subtidal ones . Only dur-

ing the last stage of fracturing the fissures were filled with

coarse crystals of calcite . The presence of thinly laminated do-

lomites with algae, the sparse pseudomorphoses after evaporit.es

the presence of sphaerulites (length - slow chalcedony), . desicca- tioncracks, tepee structures (P1 .11/4), zonal development of the early dolomitic cement (P1 .111/5) and, on the other hand, the chemical analyses (Table I) and the good stoichiometry of the do lom ite crystals in certain dolomite samples lead to the conclusion that the dolomitization took place in a very early diagenetic stage.

It was caused by the replacement of magnesian calcite or arago- nite by dolomite, under the influence of saline waters, or the mixing of the latter with fresh waters . But even active influence ®39

of algae and bacteria to the process of dolomitization (ZENGER & DUNHAM, 1980) cannot be excluded. The determination of the stoichiometry of the dolomite crystals was carried out by X-ray diffraction (FUCHTBAUER & GOLDSCHMIDT,

1966), which revealed their normal composition (Cana-50,5 Igee-49,e) . Similar early diagenetic dolomites are known from

literature, more specifically in recent carbonate sediments, e .g. of the Bahamas (SHINN et al .,1965), Florida (SHINN & GINSBURG, 1964) and the Persian Gulf (CURTIS et al .,1963), and at the Dutch Antilles (DEFFEYES et al .,1965). Dolomitization in the subtidal zone, which amounts to big thickness, can be explained and interpreted with marine regressions (SIBLEY, 1980) . Such changes of the tidal line in a tidal flat environment of deposition were observed in the dolomites of Skopelos.

At the places where dolomites are coarse grained their sedimentary features have been destroyed . Thus, it is very difficult to define the preexisting facies . The last facies of dolomitization took place certainly in a late diagenetic or metamorphic stage. The textures of the dolomites, which are xenotopic in most cases

(FRIEDMAN, 1965), indicate that the dolomites were formed either in epigenetic conditions at a temperature of ?5OxC, or by the neomorphism of a preexisting dolomite or even by limestone replacement (GREGG-SIMBLEY, 1984) . Another characteristic feature is the presence of mosaic dolomites, in a micritic rock with a wavy extinction (P1 .111/4) . Its formation is also attributed to epigenetic conditions, under the influence of solutions having a temperature below 8OxC (MATTES & MOUNTJOU, 1980) . Finally, phe- -40-

nomena of dedolomitization, although observed in a minor degree, are usually restricted to the periphery of the dolomitic rhombo-

hedrals . The dedolomitization took place under surface conditions and the influence of a low Mg/Ca ratio, low Ph and low tempera-

ture. Samples CaO MgO Mn Zn Sr Fe Na PPm PPm PPm PPm PPm 0 .3 33 .88 20 .06 18 13 93 290 380 0 .23 32 .20 21 .22 14 15 116 210 170 0 .31 32 .48 21 .06 12 10 60 220 140 1969 32 .62 21 .55 11 13 70 110 100 0 .22 30 .94 20 .56 16 14 110 270 210 0 .12a 36 .40 16 .25 13 23 118 240 300 Table 1 . Chemistry of Pelagonian dolomites, Skopelos island.

2 .1 .2 .2 .5 . Karstification On Skopelos island, karstification is obvious in the Upper Trias- sic dolomites, but very rare in the Cretaceous limestones . The main form of surface karstification developed in the dolomite rocks is the enlargement of joints and faults . The joints

observed on Skopelos i s land are of large size and small fre q uency and become open due to the erosion of their surfaces . For karst formation large open faults also play an important part . During the geological mapping a considerable number of downfaulted dolines was mapped, which are developed in a linear arrangement

along the large faults . The karst and the dolines appear mainly in the Delfi Mountain and in the Flakes area . The karstic forms observed in this area are developed in a NE/SW direction . Their width reaches up to 10

The filling material is variable and consists of fragments of quartz, magnetite, limonite, hematite, manganese, oxides, chalco- pyrite and traces of phyrrotite . Magnetite and part of the limo-

nite is probably derived from the phyrrotite . Very often the Fe-

bearing fragments show a pisolitic structure . Within the filling material, small fragments of epidotitic, sandstone, andesitic and

carbonate rocks are included . The connecting material of the

above small fragments mainly consists of various carbonate miner-

als such as .siderite etc.

2 .1 .2 .2 .6 . Pelagonian dolomites . Comparison with occurrences in

adjacent areas

Skiathos island

PAPASTAMATIOU (1964) noted that the dolomites of Skiathos overlie the schists of the Skiathos series unconformably, and that they are of the same age as those in Skopelos . GUERNET (1971) agreed with the idea of PAPASTAMATIOU and identified the dolomites of

Skiathos with those of Skopelos . JACOESHAGEN & SKALA (1977) and

HEINITZ & RICHTER-HEINITZ (1983) came to the same conclusion.

FERENTINOS (1972) reported that Triassic -Jurassic formations on

Skiathos island are almost identical with those occurring at

Skopelos . On Skiathos, the lower members are marbles, while the upper members are dolomites which in many places are in direct contact with the underlying metamorphic formations . He also believed that the contact of the Triassic-Jurassic formations with the underlying schists would be tectonic.

Magnesia peninsula

TATARIS (1971 ; 1975a ; 1975b) distinguished metamorphosed carbonate sediments of Upper Triassic-Upper Jurassic age in the Fela- gonian zone in the areas of Velestino, Magnesian, and Mavrovou-

-4 2-

nion . These sediments consist of crystalline limestones, grading into marbles and dolomites . In the upper stratigraphic parts, bauxitic deposits were observed . In the area of Makrinitsa he located Megalodon, gastropods etc within the dolomites . According to the same author this succession of rocks is developed transgressively over the Makrynitsa-Portaria schists . With respect to the metamorphism of the Triassic-Jurassic carbonate sediments of Magnesian, he believed that it happened durin g Cretaceous (probably about the end of the Lower Cretaceous) and, thus, has to be correlated with the orogenesis which took place at the end of Upper Jurassic-beginning of Lower Cretaceous (Eohellenic orogene-

sie, JACOBSHAGEN et al ., 1976) . WALLBRECHER {1976 ; 1979 ; 1983) noted that the Triassic-Jurassic marbles of the "Pelagonian crystalline series" overlie the Upper Palaeozoic formations with a

normal contact . The age of these marbles is deducted by comparison with the similar marbles of Skiathos (FERENTINOS, 1974) and

the dolomites of Skopelos . FERRIERE (1976 ; 1977a ; b ; 1978) con-

.T .~w n ~11, A~arrnacian ."y~'. dldG redelL the'~ T~Triassic- Vud VI ..~. .c.~. at. tuuc s,s~°.v .r.as r-a+v ~cs pv .. ofvr ~ (Sarakinikos marbles) to overlie the glaucophane formations of Magnesian (Macrinitsa series) tectonically . In these marbles he found fossils (algae and conodonts) indicating a Triassic age. DAVIS & JUNG (1978) finally considered the crystalline limestones

(Sarakinikos marbles) at Magnesian tc o ver l ie the glaucophanitic, chloritic and epidotitic schists normally.

Thessaly KATSIKATSOSet al . {1980) noted that the Middle Triassic - Upper Jurassic marbles (Sarakinikos marbles) in Eastern Thessaly constitute a normal upward succession of the underlying Upper Palae- -43®

ozoic - Lower Triassic formations . In certain places, a transgressional relation of the marbles over the schists was, however, testified . The fossils Turrispirillina sp ., Involutina sp , Tro- chaminidae, and Radiolaria verified Upper Triassic age.

Euboea Island KATSIKATSOS (1970) described the Triassic formations of Central

Euboea . Referring to fossil findings, he considered the limestones and dolomites, which overlie the Upper Palaeozoic formations, to be of Upper Triassic age and to constitute a gradual upward evolution of the pelite-sandstone formation, along with volcanic rocks of the Lower-Middle Triassic series . Skyros island : HARDER et al . (1983) reported that the Middle Triassic-

Jurassic dolomitic marbles on Skyros island continuously overlie the Werfenian beds (see also JACOESHAGEN & MATARANGAS , 1989) _44-

PLATE I

1. Aulotortus sinuosus WEYNSCHENK, Pelagonian dolomites . Limno-- nari area . Sample D .178, Norian - Rhaetian, X 90 2. Aulotortus sinuosus WEYNSCHENK, Pelagonian dolomites, Lim- nonari area . Sample D .171 . Norian - Rhaetian, X90

3 .4 . Agathammina iranica ZANNINETI, BRONNIMANN, BOZORGNIA & HUBER . Top of the Skiathos Series, Ag . Paraskevi area, Sample D .25 . Ladinian -- Carnian, X100.

5 . Agatharamina sp . Top of the Skiathos series, Ag . Paraskevi area, Sample 175a, Ladinian - Carnian, X100

6 .7 . Aulotortus friedli KRISTIAN-TOLLMANN, Pelagonian dolomites, Stafylos area, Sample 1949 Norian - Rhaetian, X90

8 . Aulotortus sp ., Pelagonian dolomites . Limnonari area . Sample D .178, Norian - --Rhaetian, X90

-46-

PLATE II Microfacies of the Pelagonian dolomites.

I . Algal laminated dolomite (Microfacies 1). Fenestral void with micritic-microsparitic internal sediment can be distinguished. Sample E65, X30, // Nicols. 2. Algal laminated dolomite (Microfacies 1) . Several generations of internal sediment in fenestral void and crack of algal laminae can be distinguished . Sample E65, X30, I/ Nicoll. 3. Dolomitized evaporite minerals (anhydrite) having arozeta' shape are observed in microfacies 4 (spongiostroma) . Sample E48. X120, // Nicols. 4. Microtepee fabric . Sample 259, X30, //Nicols. 5 . Laminated dolomicrite--dolomicrosparite (Microfacies 5 044, X30, // Nicols .

P L ATE III Microfacies of the Pelagonian dolomites.

I . Foraminif.era-rich dolobiopelm,icrit.e (Mic-rofaci.es 2) . Subtidal depositional environment . Sample 1949, X30, // Nicols.

in fene.stral cavity . Sample E68, X30, :// Nicols.

3 . Homogenous doiomicrite-do lomicrosparite Sample 1905, X30, //Nicols

5, Dolomite crystals in zoned growth. Sample 017, X50 . //Nicols

-49-

2 .2 . Glossa unit (Eohellenic n PP e )

The Glossa unit occupies the north-western part of the Skopelos

island, where the homonymous village of Glossa is located . . The south-eastern limit of this unit is defined by the village of Klima at the western coast and the Ag . Ioannis chapel at the eastern coast (F'ig .15). The relief of this area is asymmetrical with steep slopes in the western and northern parts of the island, whereas the eastern

lenic nappe was thrust upon the Pelagonian unit ; more precisely, on the Pelagonian dolomites (Panormos and Loutsa areas) and on the metaclastic Skiathos series (Fig .16) it will be shown later on, further remnants of the Eohellenic nappe, which is also found on other North Sporadesislands and upon the Pelagonian Zone of mainland Greece, have been located at the base of the Palouki unit and also in the area between the Revithi and Nissi hills_ below the UpperUpper Cretaceous carbonate rocks . A further small outcrop in the Panormos area with a small ophiolite relic had been interpreted as a remnant of this nappe (JACOBSHAGEN & SKALA,

1977).

2 .2 .1 . Previous work The metamorphic rocks of the Glossa series were noticed in many publications since the last century (VIRLET . 1834 ; PHILIPPSON. 1901 ; PAPASTAMATIOU & ARINOS . 1938 ; 1940). RENZ (1955) regarded the Glossa schists to be the same as those on Skiathos island . According to PAPASTAMATIOU (1964), the m5 0®

L EGE~D

PELAGONIAN-MESOAUTOCHTHONOÜS GLOSSA UNIT

Flysch Cipo] Ines

A A. A Upper Gretaceous A A A A A Metabasalts 1 limestones

~Art A Fe-Ni-Laterites and h .. Schists Ati A Bauxites MIn ~ Pelagonian dolomites

Skiathos series

Fig ..I5 . The Glossa unit . ®5 1®

Fig .16 . The Glossa unit overthrust upon the Skiathos series.

schists and phyl l ites of the Glossa area, form the geologic basement of Skopelos island and have been metamorphosed in various stages . GUERNET (1971 ; 1974) compared them to the Seta series of the Euboea island, which is ^f u~~er° Palaeozoic age . jACOBSHAGEN

& SKALA (1977) noted that the Glossa unit comprises greensehists, phyl I ites, calcschists, cipol ines, with Werfenian beds in its upper members . Concerning its age they compare the Glossa series to the Upper Paleozoic-Lower Triassic Skiathos series . SCHWANDT (1953) described the formations of the Glossa series with more detail . He considered them to be the geologic basement of Skope- los island. Thus, all former authors believed the Glossa rocks to have been W52®

part of the Hercynian basement of the Pelagonian zone on Skope-

los . Only recently MATARANGAS & JACOB .SHAGEN (1988) presented a

and tectonic arguments .' they intepreted•it .to be . part of the Eos

hellenic nappe.

intercalations of impure marbles.

Metabasalts : These greenish schists ;of igneous origin are usually

intensively folded (Fig .17) . They

Lary rocks and volcanosedimentary layers . The metabasalts are

fine to medium grained with massive or oriented and mainly micro-

folded texture and very often characterized by intense tectonic

deformation . Their original structure and texture are rarely preserved and even more rarely their mineralogical composition, which is feldspars (albite + oligoclase) ¢ actinolite A- epidote

(clinozoisite/zoisit ,f- epidote) + chlorite + white mica i- quartz

titanite ~ leucoxene . These minerals are accompanied by abun-

dant Fe-oxide-hydroxides as well as calcite . In a few samples,

residual pyroxene crystals have been observed, which were identi-

fied as augite.

Amphibole crystals are frequently observed as well, with changing

composition from the center (actinolite hornblende) to the outer rims (actinolite) . Amygdaloidal lenses consisting of epidote, chlorite and quartz or/and only quartzes (with mortar texture) have also been observed . The mineralogical paragenesis of chlor-

ite ~ zoisite / clinozoisite ¢ actinolite + albite + quartz is -53-

Fig .17 . Metabasalts near Gourouni cape.

typical for low grade metamorphism according to WINKER (1976) or greenschist fades.

According to JACOBSI-JAGEN and SKALA {1977) this metamorphism was a result of the Mesohellenic orogeny which took place in Eocene times.

Mica-chlorite-calcite echist : These rocks are green with dark spots in places due to the presence of organic material . They are medium-grained, often tectonized with oriented, laminated and microfolded texture . Their mineralogical composition is as fol-- lows.

white mica + chlorite 4- quartz + calcite + titanite ~ leucoxene.

Abundant Fe-oxides-hydroxides exist in the form of idiomorphic crystals, whereas feldspar and epidote crystals are very rare.

Chlorite-mica-quartz schists ; They are of white colour,and show an intense schistosity and microfolds . They are composed of

®54

alternating thin-bedded phyllosilicate minerals and small sized

quartz grains . Among the phyllosilicate minerals, white mica is

dominant, whereas chlorite occurs in smaller proportion . Some

hypidiornorphic titanite crystals were . identified as well as euhe-

dral crystals or frameboits of Fe-oxides and hydroxides . The

presence of organic material is frequent along with the phyllo-

silicate minerals. -blondish

colour and strictly .oraented"and laranated .texture . Their maner-

white mica (sericite, phengite) + chlorite + quartz g feldspars

(albite) q epidote q leucoxene.

Fe-oxides and Fe-hydroxides were identified in minor amounts, as

well as few grains of tourmaline, apatite and zircon.

Cipolines: Cipolines are chloritic-micaceous--calcitic marbles

They appear within the higher stratigraphic members of the Glossa

unit . Their colour is white-green, their bedding is distinct,

their structure isv medium-gra i ned ae .a nd•ew wtheir texturee••~+ .++ ~+ massive . They

consist mainly of medium sized grains of calcite and very small

amounts of xenomorphic quartz grains and feldspars . The rocks are

characterized by the presence of thin, sometimes discontinuous

bands of chlorite+white mica+leucoxene+epidote+tourmaline. '4i `rv, s Finally, qumr fZ ä iron-manganese occurrence were observed in different stratigraphic levels within the Glossa unit . They occur

in small lenses with massive texture . Besides the metallic min-

eral piemontite, chlorite, quartz and albite occur within the

lenses . In addition these lenses are cut by secondary quartz and

carbonate veinlets . 2 .2 .3 . Geochemistry

For the study of the chemistry of the metabasaltic rocks of the

Glossa unit, seventeen rock samples were analyzed for the major

elements and certain trace elements using X-ray fluorescence

(XRF) and Instrumental Neutron Activation Analysis (I .N .A .A .)

techniques . The results of the chemical analyses are summarized

in Table 2 and their precision and accuracy range from better

than 5% to about 10%.

Since one of the problems in the interpretation of volcanic rock

chemistry is that of the secondary alteration, caused by either

hydrothermal activity or low-grade metamorphism, the diagrams I

and 2 of Table 3 (GRAHAM, 1976 ; STILL TAN & WILLIAMS, 1979 ) were

applied . The plot of the available data in diagram 1 and 2 of

Table 3 indicate that only a certain number of the analyzed

samples possess normal basaltic composition with respect to cal-

cium and alkalis . This can be explained by sodium enrichment in

plagioclase feldspars concomitant with depletions in calcium and

relatively constant potassium . This feature was also deduced from

the microscopic studies . All these data suggest the well known conclusion that only elements that are generally accepted as

immobile or less mobile can be used in the interpretation of geochemical data for deducing petrogenetic characteristics and processes.

The tholeitic affinity of the studied mafic metavolcanic rocks with their MORE like characteristics is presented in the diagrams

3A, 3B, 4A, 4B, 4C, 4D, 5 and 6 (Tables 3 and 4),according to the method by PEARCE, (1979), FLOYD & WINCHESTER, (1975), PEARCE,

(1952) ., PEARCE & CANN, {1973), PEARCE et . al . , (195.4) Of the limi-

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

wt 25 27 29 6 .37 6 .39 6 .64 64 68 82 83 85 88 107 117 119 1961 1964

SiO 2 43 .34 51 :30 46 .66 43 .98 51 .75 45 .40 51 .00 45 .04 51 .00 47 .00 50 .47 47 .00 41 .7 46 .67 49 .24 40 .87 48 .7 A1203 15 .74 16 .13 15 .76 14 .67 17 .36 17 .58 13 .98 17,93 14 .20 14 .20 14 .01 13 .80 18 .25 15 .30 14 .88 14 .77 16 .10 Fe203 9 .57 12 .16 8 .66 11 .03 10 .10 11 .18 10 .54 10 .15 13 .48 17 .10 11 .05 17 .60 12 .84 11 .24 9 .25 8 .35 9 .80 MgO 6 .24 5 .89 8 .75 7 .10 3 .37 6 .56 3 .01 3 .95 7 .80 8 .00 7 .64 5 .30 7 .44 6 .71 6 .32 3 .50 8 .60 MnO 0 .16 0 .14 0 .16 0 .26 0 .17 0 .16 0 .18 0 .17 0 .10 0 .34 0 .21 0 .15 0 .27 0 .16 0 .15 0 .15 0 .15 CaO 14 .03 4 .14 10 .57 10 .56 11 .10 11 .04 14 .67 12 .43 9 .20 7 .60 5 .71 10 .10 8 .93 13 .74 11 .20 17 .80 8 .80 Na20 3 .45 4 .23 3 .42 3 .97 3 .66 2,70 1 .52 2 .83 3 .50 3 .20 1 .48 2 .80 2 .10 2 .08 3 .44 2 .74 3 .07 K20 0 .05 1 .18 0 .38 0 .05 0 .08 0 .38 0 .13 0 .75 0 .25 0 .10 0 .12 0 .31 0 .19 0 .06 0 .07 0 .42 0 .94 TiO2 1 .25 1 .01 0 .93 1 .62 1 .50 1 .75 1 .92 1 .34 1 .00 1 .80 1 .42 1 .90 2 .02 1 .53 1 .35 1 .01 1 .30 P205 0 .01 0 .085 0 .073 0 .144 0 .143 0 .134 0 .20 0 .17 0 .05 0 .12 0 .13 0 .11 0 .09 0 .12 0 .11 LOI 6 .00 3 .70 4 .60 6 .60 _ 3 .00 2 .50 5 .60 - _ 8 .06 1 .00 6 .00 2 .00 3 .50 10 .00 2,00 TiPPm 74 .69 6055 5162 9694 9040 10521 11510 8033 , 5995 10791 8513 11390 12110 9160 8093 6330 7757 TOTAL 99 .84 99 .96 99 .96 99 .98 99 .25 99 .98 99 .65 100 .36 100 .54 99 .39 100 .20 99 .97 99 .87 99 .60 100 .20 99 .73 99 .57 Ti /Zr 77 95 69 80 92 77 69 83 81 76 86 74 77 83 Zr/Y 3 .46 3 .05 3 .00 3 .27 2 .80 4 .03 3 .55 2 .44 3 .00 3 .48 2 .82 2 .27 3 .72 3 .44 PPm Zr 100 64 75 121 98 137 167 97 105 160 107 109 82 93 Cr 219 21 219 205 260 315 146 296 280 358 308 282 212 280 Y 28 .21 25 37 15 34 47 33 35 46 38 48 22 27 Ni 123 25 .206 119 206 168 77 102 88 186 188 94 79 118 Cu 51 129 51 62 29 45 <5 34 331 128 54 54 52 54 Zn 76 98 51 85 92 90 45 72 126 74 65 33 76 45 Pb 10 . 9 20 4 17 5 7 15 9 10 6 4 37 19 Sr 211 206 A 106 446 185 342 266 234 461 186 284 203 171 Rb 3 20 12 3 6 10 <5 23 <5 5 3 11 16 21

Tb1e 2 . C1°a®istry of afic rocks from the G1o a unit of Skopelos island. An~ by~~ ~ by XRF nd INAA. -5 7-

ted number of elements from the Low Field Strength (LFS), the

normalized values of the lithophile L .I .L . Elements (SAUNDERS et

al .,19SO), which belong to the MORE like basalts of the mafic metavolcanic rocks of Skopelos island, show higher ratios of

L .I .I ./H .F .S . This variation in the chemical composition of the rocks may be the result of partial melting processes and crys-

tallization within the upper mantle during the genesis of the

p arental magma and the following fractional crystallization. Apart from the differences in the partial melting degree, the variations in the fractional crystallization of the ferromagnesian

facies are indicated by variable Mg values 25 to 53 (=IMO Mg/Mg+

+Fe 2 -`) and also by the Cr and Ni abundances (Table 2).

The most important conclusions are: a) The metavolcanic rocks originated from fine to medium grained subophitic and rarely amygdaloidal lavas . Pyroxene is replaced by actinolite, chlorite, epidote, and plagioclase is altered to albite and white mica . Randomly oriented chlorite and actinolite crystals are the results of the glass alteration, whereas anhe- dral grains of epidote, calcite and quartz occur both in the groundmass and the amygdales . Leucoxene and sphene replace primary iron-titanium oxides. b) The secondary mineral assemblage of the examined mafic meta- volcanics is comparable to the low greenschist metamorphic facies. c) The geochemical data indicate a tholeiitic affinity and relation to MORE-like characteristics .

®59=

Ti /100

4r. 4®

.!1 RoCl< f:. ° 1,oOZlosYt~j~1S~El ~~ MORs~.o ~

1 f-I 1 , , T 1, , . n ttrt sn glt 4net VW' 9~n 9Lf1 91z1 NiP1 K°2a1ft .c29•A31^9Yt Sr {~ R91 p Zr d v wv w v v {v v tbv rmv asp., A.v mai 6Gy rsev 61Ad eCJ -•4J Zr 6 5

T A B . I. B~ . Diagrams of trace elements from metabasaltic rocks. Glossa unit.

2,2 .4 .Gorrelation of the Glossa series with those of adjacent

areas

Before we discuss the correlations of the Glossa series with

those of adjacent areas, it has to be stressed that it is abso-

lutely different from the Pre--Mesozoic basement of the Pelagonian

nappes . The crystalline complex of Thessaly contains amphiboli- tee, phyllites, mica-schists, and metagranites . These rocks have been metamorphosed during the Hercynian orogenesis . Above these crystalline rocks follows a metaclastic sequence, which consists of graywackes, conglomerates, breccias, and schists, as it is has

been mapped in Skiathos by JACOBSHAGEN & SKALA (1977) . The same metaclastic sequence,the Skiathos series, has been described from the Magnesia Peninsula (JACOBSHAGEN et al_,1976), from Skiathos

and Skyros (HARDER et al .,1983), from Lesbos (JACOESHAGEN & SKA-

LA,1977), from Euboea (KATSIKATSOS, 1970) and from others places.

The Skiathos series is overlain by the Pelagonian dolomites. Thus, the Glossa unit does not fit into the sequence described before . Comparisons of the rock types of the Glossa series with

assemblages of the Eohellenic nappe as they occur on the neighboring islands and the Magnesia Peninsula indicate, however, that

the Glossa series has an indent composition . Therefore it might

be a remnant of this nappe . Remnants of the Eohellenic nappe have

also been described on the Magnesia peninsula by WALLBRECHER

(1983) and on the islands of Skyros . Alonnissos . Kura Panagia and

Skantzoura by HARDER et al . (1983) . The presence of Fe-Mn- quartzites rich in piemontite, which form lenses in both the Glossa series and in Eohellenic outliers of the Magnesia peninsula, . is a farther indication for their relationship . We should remind here of the fact that small ophiolitic remnants have been found in the Pelagonian unit between the Upper Triassic dolomites and . the Mesoautochthonous Upper-.Cretaceous. limestones . These ophiolitic remnants occur in the Panormos area ( .JACOBSHAGEN &

SKALA, 1977) and moreover north of the town of Skopelos and of the Palouki Unit (chapter 5 .2 .1) . -61-

2 .2 .5 . Conclusions.

The field observations and the lithological comparisons combined with the petrological and geochemical data on the Glossa unit lead to the conclusion that this unit belongs to the Eohellenic nappe and not to the Pelagonian nappes.

The lithologic characteristics of the Glossa metasediments indicate a semipelagic to pelagic origin . We should emphasize here the presence of quartzites rich in piemontite, which have been interpreted as metaradiolarites by WALLBRECHER (1983) . The new interpretation for the Glossa unit is also supported by the geochemical data of the metabasalts which are of tholeidtic character and are related to rocks with MORE-like characteristics . In a later chapter it will furthermore be shown that the Glossa series rests upon the Pelagonian unit, separated by an overthrust . ®62®

2 .3 . Mesoautochthonous

According to JACOBSHAGEN (1986), the mesoautochthonous series

comprises both the weathering events, which developed after the

Eohellenic nappe overthrust, and a Cretaceous - Palaeogene sedimentary sequence.

2 .3 .1 . Cretaceous formations

On Skopelos island, the surface distribution of the Cretaceous formations is very small in comparison with the other stratigraphic units . They occupy a central part of the island and consist of Fe-Ni-bearing laterites or bauxites, conglomerates, quartzitic schists, and limestones . These formations cover a tectonized and strongly eroded dolomitic basement with an irregular relief (Fig .18) . Their thickness varies from a few meters to more than 200 m.

Fig .18 . Upper Cretaceous rudist limestones resting transgressively on Pelagonian dolomites . They are unconformably overlain by Palaeogene flysch . Kavos Kalis area . -63-

2 .3 .1 .1 . Previous work

VIRLET (1834) was the first to identify Hippurites in limestones

north of the town of Skopelos . PHILIPPSON {1901) described a

thick cover of semicrystalline limestones, sometimes dolomites,

with rudist fragments in the central and southern part of the

island, with the exception of the town area . In the area of Sta-

fylos, he found a series of schists which includes a serpentine

body . He considered these schists to be a formation analogous to

the rudist-bearing limestones . On his geological map of Euboea

and Sporades, DEPRAT (1904) suggested that the whole island of

Skopelos consists of Cenomanian limestones.

PAPASTAMATIOU and MARINOS (1938) reported the presence of rudist-

bearing limestones at Skopelos, which lie disconformably upon

Pelagonian dolomites and dolomitic limestones . This disconformity

was observed at the cape "KALIS" on the eastern coast of the

island . VOREADIS & ZACHOS (1964) mentioned the presence of bau-

xites on Skopelos island within an unpublished internal report.

At- Limnonari Bay on the western coast of the island, PAPASTAMA-

TIOU (1964) observed a transgressional conglomerate with a thick-

ness of 10 m which contained Actaeonella and rudists . He repor-

ted, furthermore, that the Upper Cretaceous, which covers the

dolomites transgressively, consists of schists with rudist lime-

stone intercalations, the latter followed by flysch . According to

this author the Upper Cretaceous transgression begins with either

conglomerates or with schists or even with a direct deposition of

rudist limestones on the dolomites and the dolomitic limestones.

GUERNET. (1971) distinguished traces of "Globotruncana" within

Upper Cretaceous rocks . He compared them with those of Pixaria on Euboea.

JACOBSHAGEN & SKALA (1977) noted that the Upper Cretaceous con-

glomerates vary in thickness and are composed of dolomitic

pebbles . In certain places, a bauxitic layer occurs between the dolomites and the limestones of the Upper Cretaceous . The same authors also pointed out that in the area of Ditropo the Upper

Cretaceous limestones have been metamorphosed into marbles . In the area of Skopelos town, they are only a few meters thick.

2 .3 .1 .2 . Description of the Cretaceous formations

The Cretaceous formations display strong lithologic and stratigraphic differentiations both in their succession and in their lateral development (Fig .19) . They are described now in detail.

2 .3 .1 .2 .1 . Fe, Ni-laterites and bauxites

The Skopelos bauxites were first mentioned by PAPASTAMATIOU &

MARINOS (1938) from Blo (Panormos area) and Loutsa . VOREADIS &

ZACHOS (1942) believed that the bauxites found upon or within schists at Blo and Loutsa, constitute a special stratigraphic member underlying the dolomites . They also argued that the bauxite deposits are of secondary origin . PAPASTAMATIOU (1964) studied the bauxite outcrops in the areas of Blo, Georgareika, Lou- tsa, and Ditropon and related them genetically to the diabase rocks and the old tuffs of those regions . Finally, BARDOSSY

(1982) mentioned the Skopelos bauxites in many chapters of his book on karst bauxites . Based mainly on PAPASTAMATIOU'S data, he believed that they are similar to those of the Halimba Basin and assigned them, therefore, to the rare category of Jurassic karst

ANTRIM PANORMOS OTE PEFKIAS AG .RIGINOS PAPPOY

O,PO D O~O 0 GP. .0 .0 c, wpm.. IOW

Upper Cretaceous .:=,•=. Breccio-conglomerate Breccia rudist limestones o %g with bauxite lenses

Upper Cretaceous Dolomites Schists thin bedded limestones

Fig . 19: Lithostratigraphical correlation of Mesoautochthonous formations in different areas l of Skopelos island . j_,

-66-

bauxites.

In this study, the bauxites are considered to be of Cretaceous

origin according to their stratigraphic position and especially

in relation to the underlying and overlying formations . This view

follows the arguments of JACOBSHAGEN & SKALA (1977), HARDER et

al . {1983), and others . It is supported by geochemical indica-

tions (Fig . 27).

The Fe, Ni-bearing ;lateritic and bauxitic rocks are exposed in a

much larger area than described by PAFASTAMATIOU (1964) . During

our field work we mapped all these outcrops as shown on the geo-

logical map attached to this study . The main outcrops of the la-

teritic and bauxitic rocks on the island are to be found in the

areas of Loutsa and Ditropon, about 2 .5 Km east of Panormos.

The lateritic rocks occur almost everywhere at the base of the

Upper Cretaceous, the strongly eroded and sometimes karstified

Pelagonian dolomites (Fig .20).

Fig .20 . . Bauxites . overlying the Pelagonian dolomites in theParnomos(Bio) area . ®67-

They are overlain by Upper Cretaceous limestones . Frequently they

occur as lenses or interbedded bands (Fig .21) within the trans-

gressive breccio-conglomerates (see 2 .3 .1 .2 .2) or even constitute

their matrix.

Fig .21 . Bauxitic - lateritic bed within the Cretaceous breccio- conglomerates . Panormos area.

Finally, the lateritic and bauxitic rocks can also be found as

fillings of karst pockets within the dolomites . PAPASTAMATIOU

(1964) described the €p resence of two bauxitic horizons . The first

is interbedded with dolomites and is accompanied by tuffs (Fig.

22) and other igneous rocks, and the second is overlain by a

dolomite breccia formation . In our view the bauxites are closely

associated with the presence of the Boheilenic nappe . Their rela-

tions to the igneous rocks of the Panormos area have already been

described by JACOBSHAGEN & SKALA (1977) . These authors interpre-

ted the volcanics as secondary reworked relics of the nappe which

existed during the Upper Jurassic-Lower Cretaceous . Thus the laterites and the igneous rocks would belong to the same stratigraphic horizon .

- 66-

During my work in the Elo area, it became obvious that the second

bauxitic horizon, according to PAPASTAMATIOU (1964), belongs to

the palaeokarst fillings . The thickness of the lateritic rocks

varies from site to site and ranges from a few centimeters to

about 5 m . Along with the lateritic rocks we find . diabases, tuffs

and breccias which consist of fragments of ..schist, di .abases, do-

which is the . main constituent :(diasparic bauxite) . Secondary cm-

and consist of diaspore and iron oxides-hydroxides with or with-

out concentric laminae . As a rule, their dimensions are small and

their diameter is about 0 .1 mm . Bauxitic breccias composed of

bauxitic and schist fragments are rare . A large number of samples

were collected from the laterite and bauxite outcrops . The sam-

ples were analyzed for SiO 2 ,MgO,CaO .TiO2,K2O,Na2O,Ni,Co .Cr .Mn.

The results are shown in Table 5 . From this table it is evident

that the rocks are indeed Fe,Ni-laterites and bauxites . The bau-

xites analyzed are plotted on a SiO 2 --Fe 2O0-(Al203+-TiO2)

triangular diagram (Fig .23) . From this diagram it is evident that

the . .. Skopelos bauxites plot on the neutral oxidation field, which

means that their lateritisation and bauxitisation has occurred

under oxidizing conditions . in a neutral environment (VALETON.

1972)

Fig .22 m Tuff outcrop in the Loutsa area.

Samples Si0_ TiO A120 FemO :3 Co Cr Ni

1 07 10 .50 3 .10 64 .00 5 .90 300 .00 600 .00 300 .00 2 047 15 .30 2 .10 42 .30 22 .00 300 .00 1500 .00 1500 .00 3 050 3 .00 3 .10 65 .00 17 .00 300 .00 600 .00 500 .00 4 051 4 .00 2 .40 53 .00 22 .00 500 .00 600 .00 600 .00 5 055 19 .00 2 .60 42 .50 15 .00 400 .00 500 .00 900 .00 6 78 11 .00 2 .60 49 .00 26 .00 400 .00 800 .00 2000 .00 7 83 15 .00 2 .50 44 .00 21 .50 300 .00 1000 .00 1000 .00 8 85 4 .00 3 .10 54 .50 24 .50 400 .00 600 .00 1000 .00 9 88 13 .00 2 .60 59 .00 10 .20 300 .00 500 .00 400 .00 10 1904 12 .00 2 .50 57 .00 8 .50 400 .00 600 .00 300 .00 11 01 52 .50 1 .30 23 .50 13 .50 400 .00 500 .00 500 .00 12 16 65 .50 1 .10 16 .30 9 .90 300 .00 700 .00 500 .00 13 84 38 .50 1 .80 27 .30 20 .00 400 .00 2500 .00 1000 .00 14 98 80 .00 0 .50 7 .50 5 .10 400 .00 300 .00 400 .00 15 99 31 .50 2 .10 33 .50 17 .00 400 .00 1200 .00 1500 .00 16 100 65 .00 1 .00 16 .00 9 .00 400 .00 400 .00 500 .00 17 197285 .00 0 .30 4 .50 5 .40 400 .00 300 .00 500 .00 18 1973 7 .50 1 .00 14 .00 6 .90 400 .00 600 .00 700 :00

Tab : 5 . Chemical analyses of aterites and bauxites from the Skope l os island

,,.70..

Fig .23 . Plot of the Skopelos bauxites on the SiO 2 - Fe203 (A1 2 0 3 +T10 2 ) variation diagram.

For comparison we plotted, moreover, all lateritic samples ana-

lyzed onto the same Si0 2 -°F'e 20 3-(Al 2 0 $ +Ti0 2 ) triangular diagram

(Fig .24) . Two fields can be noted on this diagram (B=bauxites and Si 02

. Fe203 . AI 2 03a T i 02

F'ig .24 .F'-lot of the laterit i c rocks of Skopel os on the SiO 2 - Fe 203 - (A1 203 + TiO2 ) triangular L=Fe-Ni bearing laterites and B=Baux i tes.

I.-laterites) ~s for the trace elements Co,Ni and Cr . their

®7I

plots on a triangular diagram (Fig .25) lead to the conclusion

that the lateritic rocks of Skopelos form a unit with a wide

range of contribution ratios of the three above-mentioned trace

elements, the Co contribution being the lowest.

Ni Cr

Fig .25 .Co-Ni-Cr variation diagram for lateritic rocks of Skopelos

The issue of the genesis of the Greek laterites and bauxites has

been an important problem for many years . There are conflicting

views on the subject even nowadays, but in general it is accepted

that they probably originated from the lateritic decomposition of

basic and ultrabasic rocks (ophiolites) . The opposite view that

they resulted from the decomposition of carbonate rocks is losing

ground . As to the Skopelos bauxites, PAPASTAMATIOU (1964) argued

that they originated from diabases and old tuffs . This view is

strongly supported here, because it is reasonable to assume that

the above-mentioned igneous formations were decomposed very

easily and, thus,contributed substantially to the genesis of bau-

xite . It would, furthermore, be reasonable to argue that such a -72-

contribution of the metabasalts cannot be negligible . This argu-

ment is also supported by the fact that on the logC(Cr)v/logC(Ni)

diagram (TUREKIAN & WFDFPOHL, 1961) the average values of Cr(700

ppm) and Ni(760 ppm) of the Skopelos bauxites (Fig .26) plot near

basalts i .e . near a rock of mafic composition, which supports our

interpretation . Corroborative evidence is also provided by the

Fig .26 . Plot of Skopelos bauxites (average value) on the log C (Cr) v . log C (Ni) diagram.

significant presence of Ti,Co,Ni,Cr . These elements are, as is

well known, abundantly found in mafic-ultramafic rocks . Finally,

the component oxides SiO-2 ,Fe 2 O3 and TiO 2 of the Skopelos bauxites

and Fe,Ni laterites are plotted against A1 203 . On the resulting diagrams (Fig .27) we can see the negative Al 203/SiO2 correlation as well as the positive Al 2 03/Fe 2 03 and A1 203/TiO3 correlations.

The geochemical composition of the Skopelos bauxites even allows

6a-

50 =

40-

30-

2.0-

10-

i 1 i 1 - 1 r r 1 l1 10 20 30 40 50 60. 70 60 90 100 A1203

1 r 1 1 r 1 1 7 i 10 20 30 40 50 60 70 80 90 100 A1203

0 15-

1a-, % 0

11111. 11 1 . 1 i 10 20 30 40 50 60 70 •80 : ... 90 .100 A1 203

o Bauxites o Lateri tes

Fig . 27® A120:3-SiOw . TiO~ and (FeOi-Fe:G.O) correlations

-74-

an estimation of their age . With average values for Ni= 760 ppm

and Cr= 700 ppm, they plot in the field of Cretaceous bauxites of

Greece, according to PANAGOS & KRITSOTAKIS (1988), as shown in

Fig .28.

ß 2000-

1500- d

E a 100 0 -- z

500 - © o ~ o 0 ® q q

0 -,1 r 50 500 5000

Cr (ppm)

Fig .28 . Cr v . Ni diagram of Jurassic im Cretaceous ß bauxites in Greece (after PANAGOS & KRITSOTAKIS, 1988) . Skopelos bauxites

This fits very well to their stratigraphic position . Finally, it

has to be mentioned that MPOSKOS & LIATI (1990) determined the

metamorphic conditions of the laterites and bauxites of Skopelos.

The mineral assemblages of the metabauxites chlorite - diaspore -

hematite _ rutile . chloritoid - diaspore - pyrophyllite - hema-

tite - rutile, and . the Fe--carpholite in the metapelites -- meta-

sandones, suggest metamorphic conditions of the blueschist

facies, according to these authors . -75-

2 .3 .1 .2 .2 . Breccio-conglomerates

This term comprises compact carbonate rocks with a characteristic breccio-conglomerate texture, which are widespread at the base of the Upper Cretaceous, marking the Mesoauthochthonous transgression . Their thickness varies from a few centimeters to about

100 m, owing to their deposition in the Lower Cretaceous relief mentioned above . The clasts are of dolomitic composition, whereas the matrix is predominantly calcitic or, in some places, lateritic . The size of the clasts varies from area to area as well as within the same site from a few to about 70 centimeters.

In general, these psephites are unstratified and unsorted except for up to 1 m thick beds which are developed in the areas of Pan- ormos and Ag . Reginos (Fig .29) . The breccio-conglomerates usually rest upon Pelagonian dolomites ; only at very few localities they are found on laterites or bauxites.

Fig .29 . Thin-bedded (1 m) transgressive conglomerates of the Cretaceous Ag . Reginos area . ®7G

The big differences in thickness, bedding (well bedded to totally unbedded), sorting (sorted to totally unsorted), size of fragments or pebbles, and shape (angular to very well rounded) suggest that the transgression took place on a substratum of a very pronounced relief . They suggest,furthermore, that the conditions of deposition varied widely . This relief indicates an important uplift before the deposition of the breccio-conglomerates formation . Some typical outcrops of the breccio-conglome - rates are described in the following section.

Panormos - Blo area In this area on the western coast of the island, the transgressive breccias attain their maximum thickness . The Georgareika hill to the east of Panormos Bay consists almost entirely of breccias the thickness of which exceeds 100 m . Here, the breccia s are underlain by Pelagonian dolomites with a very pronounced relief (Fig . 30).

Fig .30 . Cross section of Panormos area . The components of the breccia are of dolomitic composition, rang-

ing from white to black colour, from 1 to 15 cm in size, totally unsorted . Combined with the variation in fragment size, this shows that the degree of reworking was low and the transport distance short . On the same hill at an altitude of 90 in, a small phacoid bauxite layer being about 300 m long and 1 m wide, is exposed between the breccias . Smaller bauxite lenses are also present in different horizons within the breccias.

Cape Andrinia area

This area lies on the northern side of Panormos Bay . Contrary to the previous site . where breccias are present, here we find conglomerates . The pebbles are dolomitic whereas the matrix is calcitic . This site is characterized by the rapid lateral wedging of the conglomerate, the thickness of which begins at 30 na and thins to 3 m within a very short distance . The pebbles are uni- form in size and their diameter does not exceed 10 cm . These conglomerates show a microcavernous erosional surface, at present.

Pefkias area

In the area of the Pefkias hill north of Limnonari Fay, and at a distance of about 750 m, the Cretaceous transgression begins with a 20 m thick formation consisting of large angular shaped dolomite fragments cemented by calcitic material . This megabreccia is overlain by thin-bedded Cretaceous limestones which grade into thick-bedded ones in the higher part (Fig . 31) . Most typical for this formation is the large size of the fragments . This must imply that these fragments originated by tectonic activity and also that" they were not transported over a considerable distance before their deposition . -78=

oe mean DOLOMITES

~a~ n THIN-BEDDED -sarsl LIMESTONES

QA ao MEGA-BRECCIA

0 eo m

Fig .31 . Cross section of Pefkias area.

Reginos Monastery area This area lies about 2 km south of the town of Skopelos . Here the transgressive formation is represented by conglomerates again. These conglomerates are quite massive and cover a large area. Their thickness attains 80 m around the Monastery and decreases progressively to the south . They are underlain by Pelagonian dolomites, which show in some areas a very thin bauxitic"interbed". The pebbles are dolomitic and of varying size, their diameter reaches u p to 10 cm and the matrix is calcitic . Towards Pefkias hill, the pebbles are more rounded than in the area of the Regi- nos Monastery . Similar as in the Panormos area the conglomerates are well bedded . The sorting of the pebbles is poor . Between the dolomites and the conglomerates near the Reginos Monastery we noted a limestone layer up to 20 cm thick which includes dispersed dolomiticlithoclasts . At certain sections samples were collected from the Ag .Reginos conglomerates, covering .. . their entire lithostratigraphic width . In some of the thin sections

®79-

made of these samples microfossils were detected within the cementing material . These particular thin sections were of samples collected at the base of the conglomerates and at a perpendicular distance of 30 cm from their contact with the underly-

ing Triassic dolomites .. The micrvfossäls identified were:

Valvulammzna picardi HENSON Zezzazata con vexa F'LELTR1' Discocyci ina sch1 um.öergeAi isäül'+IT Esa-CHALMAS Pseurlotextula.riella sp. Gavelisella sp. Spirolooulirra sp. Rotal i idae Miliolidae 0acycladaceae This microfauna suggests that the deposition or the conglomerates

Researchers up to now assigned these conglomerates to the formations of the Cenomanian transgression without having determined their age . Thus, it cannot be excluded that the Cretaceous transgression in the neighbouring regions of the Northern Sporades and the Magnesian peninsula might have taken place earlier than was

r ,v l P~ .-. s~ .-.~.~s .'d~~. rmw .~rF®,3 ~Z. lÄ~~oe~7GlL UP to now L~r GdlV6EdtA380C3.6i1 • Several+JG VV d ~.i~ authors ld{dYVhave d vg,~va I.vLS

similar ages in Argolis (EACHMANN & RISCH, 1979) . Euboea (CLE- MENT . 1983), Thessaly (EERRIERE, 1982) . island of Salamis (TATARIS et al . 1980).

2 .3 .1 .2 .3 . Quartz schists In several places, the Cretaceous deposits start with quartz schist, which are rich in iron oxides and hydroxides and alter- nate with limestone beds . This formation was detected only at one

site, namely on the main road from the town of Skopelos to Panor-

mos . a few meters before the cross-road near the hill of Alikia . These schists are underlain by Pelagonian dolomites, . about 10 meters thick and contain several limestone beds up to 0 .30 m thick . Gradually, the formation passes into the Upper Cretaceous

limestones (Fig .32).

Fig .32 . Quartz schists alternating with limestones beds, Alikias area.

Under the microscope, these rocks can be characterized as carbonate-mica-quartz schists rich in iron oxides and hydroxides with oriented texture and tectonic action . They consist mainly of small quartz grains of various sizes and calcite mineral . We also noted in smaller proportions the presence of some phyllosilicates

(sericite-muscovite), which form thin layers together with the iron oxides and hydroxides . In one thin section dispersed medium- sized chioritoid crystalloblasts were noted to be frequent . The mineralogical paragenesis of these schists is:

quartz + sericite + carbonate mineral q chloritoid . 2 .3 .1 .2 .4 . Upper Cretaceous limestones

The Upper Cretaceous limestones occupy an area of less than 10 km

within the central part of Skopelos . They rest conformably upon

the breccio-conglomerates, and wherever the latter is not devel-

oped, they rest unconformably upon the Pelagonian dolomites (Fig.

19) . They are fossiliferous and their thickness ranges from a

few meters (Kavos Kalis Cape) to 200 m (Koprisies Hill) . They are

folded and intersected by a dense set of joints (see chapter

3 .2 .2) . Locally in their lower members, they are thin--bedded, in

the higher part they gradually become thick-bedded to unbedded

and finally become thin-bedded again.

What is remarkable and of paiaeogeographic

rani' directly upo unbedded (Fig .19).

A typical feature of these Cretaceous limestones is the variety of facies both vertically and horizontally . According to their macroscopic features, in particular, thickness of beds, colour, fauna,and other macroscopic observations (see below) these facies define lagoon, reef or fore reef environments, according to ENOS

(1983) and JAMES {1984) . The lower thin-bedded limestones were deposited in a lagoonal environment (Cenomanian), whereas the thick-bedded or unbedded upper parts were deposited in a lagoon or reef environment (Turanian?) and, finally, the thin-bedded -82-

limestones on the top were deposited in a deeper sea environment.

Koprisies Hill area

At Koprisies Hill, which lies 3 .5 km SW of the town of Skopelos,

the Upper Cretaceous limestones are about 200 m thick and consti-

tute one of the largest outcrops of these rocks on the island of

Skopelos . They are gray-coloured and their higher members are

unbedded and rich in rudists (Fig .33) . Laterally, they pass into

thick-bedded limestones of a lighter colour in which the per-

centage of microfossils is significantly reduced.

Fig .33 . Upper Cretaceous limestones rich in rudists, Koprisies Hill.

Under the microscope the samples were identified as bioclastic

limestones with rudists, echinodermal fragments, and ?iliolidae.

Both this fauna assemblage and the bedding features are common in

Mediterranean rudist limestones of the reef facies (in a broad sense), according to WILSON (1975) and JAMES (1984) . Joints and fissures are common, the latter being filled with calcitic mate- rial_Small diameter karst pockets are also present, within which stalactites may have developed.

Ag . Reginos Monastery

This area lies 2 km south of the town of Skopelos . Again, the

thin-bedded lower members of the Upper Cretaceous limestones

grade upwards into thick-bedded rudist limestones (Fig .34).

F lysch so

.70 Upper Cretaceous limestones

so.

30 Limestones with nodular structure 20 ! t3i i~ .ileccl<1d linlr=s :.i_'Sles . conglomeratei T°aFlsgreslonal

Fig .34 . Lithostratigraphic column of Cretaceous formations, Ag . Reginos Monastery

The thin-bedded limestones are red-violet . Usually they show a

recrystallized microclastic structure and a rich macro- and

microfauna . The following fauna could be identified:

Diplanata peneropliformis HAMAOVI-SAINT MARC Di cycl ina schl umbergeri MUNIER - CHALMAS Biconcave benfori HAMAOVI--SAINT MARCK Merlingia cretacea HAMAOVI-SAINT MARC Cuneolina gr . pavonia D'ORBIGNY iummolocul ina heimi BONNET Cayeuxia sp. Miliolidae Rudist and echinodermal fragments

From the thin-bedded limestones the microfossils collected were

identified by Dr . KOLLMANN as : Large Trochactaeon Plesiopygmatis digitalis STOLICZKA

On the basis of this fauna (see also PI .IV), the thin-bedded

limestones are considered to be Upper Cenomanian-Turonian in age.

Between the thin-bedded and the rudist-bearing limestones, a

limestone horizon, about 20 m thick, is intercalated with an

impressive nodular structure (Fig .35).

Fig .35 . Upper Cretaceous limestones with nodular structure, Ag. Reginos Monastery.

The nodules are dark in colour, usually elongated, slightly undu- lated, and sub-parallel to parallel to bedding . They rest within a white-coloured groundmass . They are probably the result of relatively early diagenetic conditions.

Trachili and Arapi Hills

These hills lie between Panormos Bay and cape Myti on the western coast of the island . Here the Upper Cretaceous limestones overlie the basal breccio-conglomerates . Their total thickness does not exceed 50 m . Their lower members are thin-bedded micritic limestones of reddish to brownish colour, rich in microfossils . -85-

These limestones grade into dark-coloured thick-bedded rudist

limestones as well. Microscopic examination of the thin-bedded limestones identified them as micrites-microsparites with a rich fauna .The abundance of fossils and the presence of peloids and some intraclasts indicate a shallow and calm or slightly disturbed depositional environment, most probably not poor in oxygen . The fauna identified within these limestones is typical of a lagoon environment:

t'!ummofa 11 o t i a a,pu 1 a LUPERTO SINNI "Va1 vu1 ammisa" picardi HENSON i'rochospira sp. Ccr:si nol i :rsl l a sp. Miliolidae Dacycladaceae Radiolitidae Nerirasa sp. Pyrazus sp. bamellibranchiata.

The age attributed to these limestones is Middle-Upper Cenoma- nian. Chlias Hill =ma This area lies on the eastern coast of the island near the cape of tag . loannis . At this site the Upper Cretaceous limestones rest upon 0 .5 - 1 .5 m of the basal breccio-conglomerates, showing a red colour . The thickness of the Upper Cretaceous limestones is 15 m and they are overlain by flysch . Typical of these limestones is an assemblage of some synclines and anticlines, folding the formations (Fig .36). Although these limestones are recrystallized, we identified a microfauna in some thin sections which is typical both of their age and of the depositional environment :

DOLOMITES [1 FLYSCH -r] CRETACEOUS BRECCIA ;„ EE LIMESTONES BAUXITES

Fig .36 . Strongly folded Upper Cretaceous formations, Chlia Hill.

Pferl ingia cretacea HAMAOVI -SAINT M ARC "Valvulammina picardi HENSON Z?icyci i na schl umbergeri MUNIER-CHALMAS Cuneolina pavonia D' ORBIGNY Nummolocu l ina heimi BONNET

On the basis of these microfossils these limestones are of Upper

Cenomanian or Middle Cenomanian a g e . Under the microsco pe some

samples show a biomicritic character, containing charophytes,

gastropodes and crustacea .This assemblage and in particular the

charophytes indicate a brackish depositional environment (WRAY,

1977) . By dyeing some uncovered sections with Alizarin red-S we

identified the matrix as dolomitic, whereas the fossil shells are

calcitic . A brackish environment would have favoured dolomitiza-

Lion (FOLK IS, LAND, 1975) . 2 .3 .1 .2 .5 . Upper Cretaceous formations in neighbouring areas

comparisons

In this chapter the Upper Cretaceous outcrops of Skopelos island

are compared with those in surrounding areas in order to reveal

several features of the palaeogeographic and palaeotectonic

development.

Skiathos island

EEPENTINOS (1972) observed that the Upper Cretaceous formations

transgressed either on metamorphic rocks or on Pelagonian dolomites . Their lower members are well bedded, whereas in the higher part they become unbedded and include traces of "Hippurites" . He

suggested, furthermore, a lateral transition between these limestones and the flysch, which he believed to be Cretaceous in age as well . GUERNET (1971) noted that the rudist Upper Cretaceous

limestones were strongly metamorphosed . The platy limestones and the flysch that overlie the Upper Cretaceous limestones come at some sites in direct contact with the Palaeozoic schists . Accord- ing to HEINITZ & RICHTER-HEINITZ (1983) . the Upp er Cretaceous formations overlie the Pelagonic marbles unconforrnably, with transgressive conglomerates at their base . These conglomerates are up to 10 m thick and consist mainly of rounded dolomitic pebbles . Within the conglomerates, they reported the presence of mica, muscovite and chlorite-bearing quartz pebbles and ophiolitic fragments . The ophiolitic pebbles were derived from the

Eohellenic nappe on Skiathos . The conglomerates are overlain by well-bedded limestone marble of white-gray colour, followed by rudist limestones with Vaccinites giganteus(D'HO BRE-FIANAS) and

Vaccinites chaperi (D0UVILLE) . On the top they found thin- bedded limestones which they considered to have originated in

deeper water . The thickness of these Upper Cretaceous limestones

attains 350 in.

Alonissos and Peristera islands

RENZ {1927) mentioned Cenomanian limestones with Orbitolina on

the island of Peristera . KELEPERTSIS (1973) detected the trans-

gression of Cretaceous rocks followed by Orbitolina bearing lime-

stones of Albian or Cenomanian age.

Magnesian Peninsula

KATSIKATSOS et al . (1981) reported that on the Magnesian peninsula the Upper Cretaceous limestones were deposited transgressively on the formations of the Eohellenic nappe (see also WALL-

BRECHER 1983) . Their thickness attains 250 m and in their lower part there is usually a horizon with muscovite schists where the distribution of glaucophane, epidote, chlorite, sericite and feldspar is extremely low . Only at very few positions are there thin transgressive breccio-conglomerates with mainly carbonate pebbles . GODFRIAUX (1976, 1977) discovered rudists within the cementing material of the breccio-conglomerates . In the area east of Platanias WALLBRECHER (1983) observed Upper Cretaceous limestones with the same sequence . as on Skopelos.

Skyros island

HARDER et al . (1983) and JACOBSHAGEN & MATARANGAS {19.90) described the same Cretaceous sequence as on Skopelos . The. Upper Creta- ceous . formations rest on the Eohellenic nappe and comprise (from bottom to top) : Metabauxites, breccio-conglomerate with fragments cemented by carbonate or lateritic material and, finally, limestones with chlorite and quartz grains . -89-

2 .3 .2 . Flysch On the island of Skopelos, flysch crops out only in a relatively

small area . It can be found west West of the town as well as on

the north-western coast and at Kalogiros hill, forming a syncline

there . The thickness of the flysch is not constant, it ranges

from a few meters (Kavos Kalis cape) to 150 m . Its sequence con-

sists of alternating metapelites, metasandstones, quartzites,

recrystallised limestones and metaconglomerates . Everywhere the

flysch is strongly folded (Pig .37), which can be well observed at

Staphylos beach and on the eastern coast at the Kavos Kalis cape.

2 .3 .2 .1 . Previous work PHILIPPSON (1901) mentioned a series of black and yellow shales

and graywackes on top of the Cretaceous limestones and schists in

the vicinity of the town of Skopelos . These rocks were correlated with the higher strata of the island of Skiathos and considered

Fig .37•. Folded flysch at the Kavos Kalis cape ®gam

to be an Upper Cretaceous horizon . PAPASTAMATIOU (1964) remarked

that the flysch is quite typical with limestone intercalations

and constitutes the upward progression of the rudist limestones.

The same researcher also mentioned in an oral communication that

in the Panormos area, on the coast, he recognized traces of foraminifera within a limestone interbed of the flysch . With a cer-

tain reservation the latter could imply Palaeocene-Eocene age_ He

also considered the Maestrichtian to be the time of the initial stage of the flysch deposition in other areas of the Pelagonic zone . JACOBSHAGEN & SKALA (1977) compared the flyschs of Skiathos and Skopelos . As to its age, they assumed an Upper Cretaceous age without excluding the Palaeogene.

2 .3 .2 .2 . Description

The Mesoautochtonous flysch overlies the Upper Cretaceous limestones unconformably . Only at Pappous hill we observe a transition from the Upper Cretaceous limestones to the flysch by an alternation of limestones and metasandstones,

percentages of their mineralogical components ..

microcrystalline porphyroblastic with strict

crystals of the metapelites are small . The grains show interfin- ngering boundaries, thus presenting a saturated texture . In some metapelites dispersed hematite grains were observed which -91-

cause the typical reddish colour of the rocks . Finally, in some

samples a few small tourmaline neoblasts were detected.

The metasandstones preserved their original texture and can be

divided according to the, grain . size into fine, medium and coarse-

vice, biotite, ore minerals, and rutile was Also observed . The

mainly of elongated calcite crystals with a low contribution of

quartz and mica and with interbedded thin layers similar in tex-

ture and mineralogical composition to the metapelitic schists.

On the basis of the mineralogical paragenesis determined within

the metapelites and metasandstones, it is evident that the flysch

has undergone low or very low grade metamorphism . MPOSKOS & LIATI

(1990) identified Fe-carpholite among the metaclastic flysch sed-

iments,referring to which they determined the P/T conditions for

the metamorphic process that has taken place . In particular, the

lower limits for pressure were of the order of 4 kbar and the temperature varied propably between 300x-330x, but may have reached even 370xC.

The recrystallized limestones form intercalations up to 10 m thick . They occupy the higher stratigraphic members of the flysch . Their colour is black . The calcite crystals are of medium size . The rocks are not obviously stratified . They occur only in the Raches area near Skopelos town (Fig .38) and in the Panormos area, where PAPASTAMATIOU detected some foraminifera which possi- ,=.g 2-

Fig .38 . Relief of the flysch . Raches near the town of Skopelos.

lily point to a Palaeocene or Eocene age.

Finally, a conglomerate (1 .5 m thick) may be mentioned from the

Stafylos area . It is intercalated between the metasandstone.s . Its well rounded pebbles have diameters of . a few centimeters and are composed of limestones . -93

The Palouki unit occupies the north-eastern part of Skopelos island, where the homonymous mountains are situated . This area is separated from the central part of the island by the Stafylos valley which runs in N/S direction (Fig . 39). The Palouki unit has been . .thrust upon the fesoautochthonous flysch . The thrust front, extending from the Skopelos bay at the eastern coast to the Stafylos Bay at the southern coast of the island, is exposed only in a few places . Usually it is covered by scree or vegetation.

2 .4 .1 . Previous work PHILIPPSON (1901) had already discovered a series of schists enclosing a serpentinite body in the Stafyloss area, which he believed to be the lateral equivalent of the rudist limestones of

Skopelos . GUERNET (1970, 1971) described this unit briefly . He mentioned an intercalation of schists, sandstones and laminated marbles, which he supported to be of Palaeozoic origin, with relations to the Vardar zone . In addition, he mentioned similar formations from the southern part of Alonissos and from the Magnesian Peninsula . He recognised, furthermore, that the Palouki unit is overthrust upon the flysch of the central part of the island . He considered this nappe unit to be a very important element within the geotectonac evolution of the Northern Sporades Archipelago . KELEPERTZIS (1973 . 1974) supposed that the Palouki series of Skopelos continues to the western end of Alonissos . He described it as a sequence of massive marbles alternating with -94-

Flysc.h

Upper Cretaceous limestones

Palouk-i series

Serpentinites metavolc.anic rocks

Geological boundary

Overthrust

Strike and dip of beds

Fig . 39 . Geological sketch map of the F'alouks unit calcschists and thin - bedded marbles, which overlie the conglo - merates of the Cretaceous transgression conformably . Based on fossils, which were found within the limestones in different sites, he dated the Palouki series to an Upper Cretaceous age.

Consequently, he correlated the overthrust of the Palouki unit with the Pyrenaic phase (Eocene).

JACOBSHAGEN & SKALA (1977) agreed with KELEPERTZIS on the age of the Palouki series but did not correlate it with the Almopias

zone, but with the Pelagonian zone . JACOESHAGEN & WALLBRECHER (1984) stated that there are no direct indications of the direction of the Palouki overthrust . Referrin g to the metamorphism of the series and to the large isoclinal folds observed in the Pa- louki area, they concluded to a tectonic cover, over-thrust to the SW or W, which is now eroded.

2 .4 .2 . Description of the Palouki Series The Palouki unit is overthrust upon the flysch .of the Mesoautoch- thonous . The tectonic contact is very clear at the Stafylos cape at the southern coast of the island and also in another two sites (entrance of the Tripoti creek and Prodromos Monastery) . Along the thrust front serpentinites, metabasalts and schists can be

observed . The formations of this unit can be subdivided lithos- tratigraphically into a lower series (Palouki Series), the Upper

Cretaceous limestones and the flysch . They are underlain by slivers of mafic magmatites (Fig .. 40)..

2 :4 .2 :1 . Basal magmatites The lowermost parts of the Palouki sequence consist of serpentiaa- -g6®

ites, metabasalts and schists_ They have a thickness of 50 m in the Stafylos area . To overlying rocks, these magmatites show tectonic contacts .

Flysch

Rudist limestones

Lower series

Serpentinites and meta- volcanics rocks

Flysch

Fig .40 . Stratigraphic column of the Palouki unit.

Serpentinites : Slivers of serpentinites were found at the base of the Palouki unit in the area of Stafylos as well as at the thrust front in the other two sites, (Tripoti creek and Prodromos

Monastery) . Serpentinite lenses of restricted size were also identified in the area between the hills of Revithi and Nissi

-97-

the eastern coast, underneath the Upper Cretaceous carbonate

rocks . Their colour varies from dark green to brownishgreen . The rocks show a cellular texture composed of serpentine minerals

(mainly antigorite) . The presence of residual pyroxene crystals is common . Moreover, bands of chromite and magnetite grains occur.

Metabasalts : Their original structures, textures and their mineralogical composition are very rarely maintained . Where the latter is preserved, feldspars (albite + oligoclase) + actinolite + epidotes (cline- zoisite/zoisite + epidote) + chlorite + quartz + white mica +

leucoxene form the assemblage. The degree of metamorphism is low grade (WINKLER, 1976) according

to the paragenesis of: chlorite + zoisite/clinozoisite actinolite + albite + quartz which indicates the green schists fac ies . They Mica chlorite - calcite schists : are greenish, medium

v r.arä v .vi ~-$f a~,d ;ve» r~^nfnlrlsarl '.~t~?s~ttst^¢? Their : minera. I otsi - gr ~ä a asc~ VIA,“ laminated ~ .. .. ~ . ~~ . .. - -.

cal composition g s as follows: white mica + chlorite quartz calcite +. :`titani.te. leucoxene,

Fe-oxides-hydroxides in ~.diomorphic crystals.7.q 4 :. comMon ; whereas feldspars crystals are very rare . : These rock descriptions show

that there many similarities between the meta ;,aa.cmati tes of

the Palouki unit and those of the Glossa unit . This mainly con- cerns the serpentinites . The similarities of these rocks to those of the Glossa unit and their lithostratigraphic position at the

base of the Palouki unit, lead to the assumption that these base-

ment rocks have once been part of the Eohellenic nappe . 2 .4 .2 .2 . Lower series The lower series of the Palouki unit was called Palouki Series by several authors (GUERNET, 1971 ; KELEPERTSIS, 1974 ; JACOBSHAGEN & SKALA, 1977) . It is composed of alternations of thin-bedded limestones, calciturbidites with metasandstones and strongly folded phyllites (Fig .41) . The limestones are usually light-grey, but dark colours may also occur . They contain cherts in various sites . The limestones are recrystallized and have a laminated or clastic texture . The presence of echinoderm fragments and clastic noncarbonate material (mainly quartz sand) is very characteristic . The metasandstones are composed of single grains of quartz, feldspars and white mica, swimming within a very fine - grained sericitic-chloritic-quartzitic matrix . The presence of metasandstones is decreasing towards the upper members of the lower

Fig .41 . Folded parts of the Iower serie s Tripoti area. series, and they dre more and more replaced by thin phyllites layers (<1 cm), alternating with limestones . These phyllites are composed of sericite, chlorite and quartz, a paragenesis, which is not sufficient for the determination of the metamorphic conditions . It cannot be excluded that this alternation has resulted from intense diagenetic processes in connection with the thin bedded limestones . Nevertheless, for this type of interpretation the presence of fine-grained noncarbonate, clastic material is a prerequisite . Besides these rocks, which predominate by far within the lower series, dark metapelitic rocks could be observed

local-ly, in the vicinity of Prodromou Monastery . With the aim of microbiostratigraphic datations, an intense sampling was car-

ried out mainly in the thin-bedded limestones . In thin sections, the following fossils were identified:

Actinoporella podolica ALTH Clypeäna heretvae RADOJDIC Echinoderm fragments

Also, in samples of the same series at the Kafasi Hill, 500m altitude, the macrofossil Pentaptyxis (det . H . Kolimann, Vienna) was found . According to these micro-and macro-fossils,which are the first to be found in this area, the lithostratigraphic posi-

tion and the comparison to the regional geology, the lower formation of the Palouki unit can be attributed to the Lower Creta- ceous, without excluding the Upper Jurassic . Based on the description of the rocks of the lower series, we may conclude that these rocks were possibly deposited in a deeper epicontinental basin or upon a continental slope . Alternations of the carbonate and clastic sedimentation with the predominance of the latter towards the upper members characterize the conditions of deposition of the rocks series belonging to the Palouki Unit. Formations of Lower Cretaceous age have been identified for the first time on Skopelos island . Their presence is very important for the reconstruction of the palaeogeographic evolution of the

whole region, indicating that the Pelagonian zone was not entirely uplifted after the Eohellenic overthrust in Uppermost Jurassic-Lower Cretaceous times, but some internal areas remained below sea level until the Lower Tertiary.

2 .4 .2 .3 . Upper Cretaceous limestones These rocks are white massive rudist limestones slightly recrystallized and intensely fractured . Their thickness does not exceed 120 m . These limestones are limited to small areas around the Palouki Monasteries . The relation of these rocks to the underlying deposits is not absolutely clear . Nevertheless, in various sites, there seems to be a normal transition from the thin-bedded limestones of the lower series to the rudist limestones (Fig .42).

During the fieldwork, traces of rudists and other macrofossi l s

were found within these limestones . In thin sections two genera of foraminifers were identified:

KELEPERTSIS (1974) found rud i sts and a microfauna of Cenomanian Turonian age in a coresponding rock unit.

2 .4 .2 .4 . Plysch The stratigraphic sequence of the Palouki unit is completed by flysch which is found in very small occurrences near the Monaste- ries . Its visible thickness does not exceed 50 m . These rocks Fi g . Transition thin bedded limestones of the lower series to Upper.42 Cretaceous limestones,of area of Prodromos Monastery.

are intensively folded . The composition of the Palouki flysch is identic with that of the Mesoautochthonous, which was described

in chapter 4 .4.

2 .4 .3 . Summary The sediments of the Palouki unit were deposited upon serpentinites, metabasalts and schists of the Eohellenic nappe . Their stratigraphic sequence starts with a lower series composed of -102-

thin-bedded limestones, calciturbidites, sandstones and phyllites alternating with intercalated chest . . The age of that lower series is Lower Cretaceous,but Upper Jurassic parts cannot be excluded . Moreover, the sediments may testify to hemipelagic conditions . The lower series is followed by Upper Cretaceous nudist limestones with small relics of Palaeogene flysch on top. The whole unit has suffered a greenschist metamorphism and is stron g ly deformed . ®I03-

3 . . Structural Geology

From a structural point of view, Skopelos island can be subdi-

vided into a central part which is composed of Pelagonian rocks, covered by very small Bohellenic nappe relics and by Mesoautoch- thonous sediments of Cretaceous and Lower Tertiary age on one hand, and the two tectonic units of Glossa and Palouki, on the other (Fig .2) . In this chapter an attempt will be made to define the tectonic processes which caused the final geological struc-

ture and, thus, influenced the geomorphological character of the island . After the study of the stratigraphy which gives a base for the analysis of the major structures and for the age datation of the tectonic events, the various tectonic features have to be examined as well . Furthermore, an attempt is made to correlate these data with the periods of tectonic diastrophism, in order to interpret their dynamic and diachronous evolution . The tectonic elements discussed below are : Major tectonic structures, folds, faults . joints and photolineations at various scales . :

3 .1 . Major tectonic structure of Skopelos island

Pelagonian unit and Mosoautochthonous rocks The combination of folding and fracturing of rocks led to the present distribution of the Pelagonian dolomites and the sequences of the Mesoautochthonous series in the central part of Skope- los island . In general the dolomites and the overlying parts of the esoautochthonousseries are characterized by open megafolds. As. : can be recognized on the geological map, the Delphi mountain ®104®

(the highest peak of the island) is part of a big anticlinorial system with a more or less E/W direction of the fold axes . In the three observed units megafolds with a WNW/ESE and NNE/SSW direction of axes also occur . In the southern parts of the above- mentioned structure some normal faults occur, trending about E/, with a maximum step of about a few tens of meters . Thus the Mesoautochthonous series, a tectonically and stratigraphically higher unit, is displaced to a topographic lower position . Fur- ther to the south the Pelagonian dolomites form some smaller mountains, which is another indication of the folding of the rocks (Kayo Kalis in the east and cape Miti in the west).

Glossa unit The old conception that the Glossa series had been part of the Hercynian basement of the Pelagonian zone has to be reexamined,

after the description and analysis of its lithological members which are identical with the composition of the Eohellenic out-

liers in neighbouring regions . One site, where the tectonic position of this unit is very clear, is the area of Ag . loannis chapel on the north-eastern coast . As described in chapter 2 .1 .2 .1 ., the transition from the metaclastic rocks to the Pelagonian dol - omites is clearly exposed southeast of Ag . loannis chapel, more specifically, at the southern flank of an ENE striking anticline.

To the northern flank of . this anticline, the Werfenian schists

(PAP .STA ATIOU, 1964) of the Pelagonian zone are nearly conformably overlain by the metabasalts of the Glossa series with a dip of about 40x to the NNW . The contact between both series is clearly of tectonic origin (see map_ .of,Skopelos, 1 :50000).

The schists of the upper member of the Skiathos series are ®I05-

intensely folded at their contact, whereas the lower members of the Glossa unit are strongly tectonized . The latter show closed folds of dm-size with torn limbs passing over,laterally, to a fabric of small tectonic lenses . Along the contact, they are completely crumbled by cataclasis . Due to these observations we have interpreted the contact as a low-angle overthrust . Thus we may state not only the differences in lithology between the Pelago- nian schists and the Glossa unit, but also the tectonic separa- tion of both units.

It is, of course, difficult to explain the absence of dolomites between the metaclastic rocks of the Skiathos series, which normally constitute the basement of the dolomites, and the Eohel-

lenic nappe at the Glossa area, NE of the large anticline of Ag. loannis . We may, however, speculate that either the Pelagonian folds must have been sheared off during the Eohellenic obduction, or the observed overthrust was a product of the Mesohellenic col-

lision in Late Eocene time . Anyway, the different types of deformations observed in the Skiathos schists beneath the thrust p lane and in the basal parts of the Glossa series above are quite obvious . The closed folds of the Glossa rocks, the fragmentation of the metabasalts along the thrust plane, and the presence of cata- clasites testify to an important tectonic contact. Within the Glossa unit, major tectonic structures strike in north-easterly directions, as suggested on the geological map. But because of the lack of a detailed stratigraphy, it is not possible to define their character. Palouki unit The overthrust of the Palouki unit can be followed across the ®Io6 island from the bay of Skopelos to the cape Stafylos . The thrust movement of this unit to SW or W is marked by folds and boudi- nage structures facing to the W . The Palouki unit is intensively tectonized . In the whole unit the folds axes are trending NE/SW and NNW/SSE respectively . The normal faults are defining the morphology as well as the outline of the coastline.

3 .2 . Tectonic elements 3 .2 .1 . Folds

Folds are frequently observed on Skopelos . They show all ranges of size and various types of geometry, and the orientation of their axes is widely dispersed (Fig .43) . During the field study of the folds, attention was paid to the deformation of bedding planes, the B axes, and the axial planes. Pelagonian Unit and Mesoautochthonous. Within these rocks both the orientation of the folds axes and the fold geometry are not constant . Due to their lithological character, the competent neritic dolomites and limestones show only major folds, whereas smaller ones are restricted to incompetent members of the sequences, i .e ., the poorly exposed Skiathos schists and the Mesoautochthonous flysch . As shown in Fig .43, three fold systems were distinguished with respect to the directions of their axes, which are WNW/ESE, NNE/SSW, and ENE/WSW . The relative age of the first two systems could not be defined . It was, however, clearly observed that these systems were refolded in certain areas by folds having an ENE/WSW direction . According to this fact the latter system should be the youngest. All of them have deformed the Palaeogene flysch, obviously during

0 a:3

0 o -4 ra a~j 0 al rd 0 O. Z 4-1 ...I o '44 a) rd .H .p . Iv) ,a)

,.,:J u 07 4-4 o 0 OD 4 0 a) Ica u') fa. o 0 o o u 4-) 0 u Its) 0 4-) .H ~ a) rd ,-i a) a) tyi 0 .r.-I b) 4-) ~ .v ra.o -c-) (la 'ol

''Cj

(D 0 0 0 @ 0 0 fJ. ®109®

These folds belong to the third fold system with axes striking ENE/WSW. Besides these isoclinal folds, various other fold types were observed in the flysch, which exhibit a dispersion in their axis

orientation . An example of these folds is shown in Fig .45. Glossa unit In this unit there is a variability in the orientation and the morphology of the folds . Adjacent to the area of Ag . loannis, at the eastern coasts of the island, there is one fold system with

ENE/WSW and NNE/SSW . At Gourouni Cape ., at the northernmost tip of Skopelos, folds with ENE/WSW and WNW/ESE directions were detected

t .'the :western coast, ..thesfol.d,taxes run in NNE/SSW direction with the axes dipping to the SSW, or they show a NNW/SSE direction with a southeasterly dip respectively . To summarize, we state that in the northern part of the unit folds of ENE/WSW directions prevail, whereas in the southern part most of the folds have NNE or NNW directions. Palouki Unit The tectonic structure of the Palouki unit is heterogeneous. the area of Stafylos and Valanio two cross fold systems were distinguished . These folds are slip-bedding folds with a schistosity parallel to the slip plane and appear, as a rule, in all rocks and in different sizes . In the whole area of Palouki, folds with NE/SW striking axes are observed, which must be considered as the main folds of this unit (Fig .46) . Except these, other folds with a NNW/SSE direction were also observed . -110-

In the area of Stafylos it was found that the folds with ENE/WSW

axes belong to a younger folding phase, which is called b 2 . The

older phase b l appears in metasandstones and limestones, with

folds having a linear shape . Similar folds also occur at the

northern coasts of the Palouki unit near the town of Skopelos.

Fig .46 . Recumbent folds, southern coast of the Palouki area.

The metasandstones and phyllites show folds whith wave lengths varying from a few centimeters to some tens of meters . Here the older b 1 axes appear to be dispersed again in several directions

(the youngest have an ENE/WSW orientation) . Only in a few places the NNW/SSE direction appears to be younger, which leads to the conclusion that these axes originated within the same fold phase.

Summary

From the fold description of the three units it was concluded that the main directions of fold axes are NNE/SSW, WNW/ESE and

ENE/WSW . JACOBSHAGEN & SKALA (1977) had already ascertained the same fold directions . They assumed that the folds with ENE/WSW axes are younger than those running in a NNW/SSE direction. Except for the folds described up to now, the presence of open

folds with ENE/WSW axes was noted, like for example the folds observed at the area of Ag . loannis. Both from the observed intersections of their axes and from their geometric relations it is concluded that the folds with NNW/SSE axes are the oldest . But we observed in many places that, on the contrary, the folds with axes NNW/SSE are older . Thus it is possible to assume that the two older fold systems were the result of only one diastrophism and are caused by phenomena of aniso-

tropy . The third fold system, with ENE/WSW axes, is clearly younger than the others as it refolds both of them.

3 .2 .2 . Fractural systems

3 .2 .2 .1 Faults The systematic study of the faults and the definition of their relations with other tectonic data is difficult and often doubt-

ful due to various reasons . In many cases it is not possible to

Finally it remains doubtful how often and in which. fashion certain faults have been reactivated in the course of time . More- over, the analysis of the Skopelos faults is inhibited by the dense forests and soil coverage . The study was carried out mainly along road cuttings and especially along the coasts . Most of these faults can be well observed from aerial photographs at the scales of 1 : 33 .000 and 1 : 8 .000 . The fault pattern is shown in

®112®

Fig .48 . There are many faults in Skopelos, most of them being

normal ones with an average extent of about 1 km, but being dis-

proportional to the fault displacement . Along certain faults a very large displacement was observed, e .g . in the area of Alykia, where the flysch lies in a tectonic contact with the Triassic dolomites. In a rose diagram containing all faults measured on Skopelos, four maximas can be distinguished (Fig .47) . They can be classi- fied, according to their directions, as follows: I WNW/ESE (100°-11O )

II NE/SW (050 * -050°) III ENE/WSW (080°-090 9 ) IV NW/SE (130°-140 ® )

'ig .47 . Rose diagram of the faults measured on Skopelos. n=100. The radius represents 10 % of the faults .

-114-

Out of about 100 faults mapped in Fig .48, only on very few of them striations were observed to determine the relative movements . One of these faults lies in the area of Karyes at an altitude of 450 m and has an ENE/WSW (080°) direction . Here the ver- tical displacement is considerable, because the flysch is in tectonic contact with the Pelagonian dolomites . Furthermore, a hori-

zontal displacement is present, which was estimated to a few hundred meters. During this study, ENE/WSW faults, however, were found on the island, along with an ENE/WSW photolineament system (chapter

6 .3 .2 .3) and a joint system striking 065° . Thus, we assume that these surface faults of Skopelos reflect the fault tectonism known from the north-western part of the Aegean sea.

3 .2 .2 .2 . Joints Joints constitute the most common tectonic elements of Skopelos. Our knowledge about their origin and their relation with the other tectonic elements, however, is incomplete due to the great number of the parameters on which the formation of joints depends . On Skopelos island the study of the joints was carried out by measuring of a few thousand joints in 77 locations

(Fig .49), in every geologic unit and formation . The measurements were statistically elaborated and rose diagrams and stereographic pole diagrams in SCH IDT'S net were drawn. In the Figs . 50 and 51, 16 rose diagrams and stereographic pole diagrams are presented . The locations of the measured joint systems are given in Tab .6. The relevant concentration curves of the stereonets for the ®II5-

majority of the sites were sketched for < 10%, 10/20%, 20/30%

30/40%, 40/50 and more than 50% concentration.

Both the frequency and the size of the joints vary from place to place and from unit to unit . Within the carbonate rocks joints

M A P OF JOINT MEASUREMENTS SKOPELOS ISLAND .

Fig .49 . Sites of joint measurements on Skopelos . Sites I II III IV Dip .of beds

1 175-355 070-250 100-280 183/35 6 025-205 145-325 195/35 8 145-325 165-345 136/10 10 155-335 110-290 035-215 225/25 16 085-265 175-355 145-325 114/20 17 025-205 100-260 192/22 18 025-205 005-185 075-255 200/15 20 075-255 095-275 115-295 060-230 264/45 21 075-255 035-215 155-335 190/15 22 125-305 155-335 035-215 194/25 23 065-245 155-335 158/22 25 065-245 140-320 192/25 26 145-325 165-345 182/20 74 085-265 115-295 106/25 12 075-255 005-185 165-345 175-325 100/42 28 165-345 015-195 115-295 122/15 30 145-325 035-215 115-295 120/20 32 145-325 175-355 045-225 015-195 212/22 33 005-185 155-335 045-225 178/50 43 155-335 065-245 160/45 45 045-225 115-295 175-355 170/35 49 145-325 115-295 045-225 112/14 52 055-235 005-185 075-255 238/52 59 135-315 005-185 155-335 240/35 61 125-305 005-185 025-205 225/30 63 165-345 045-225 005-185 144/50 65 025-205 095-275 005-185 118/30 66 105-285 175-355 258/28 68 095-275 155-335 065-245 105/15 69 105-285 1757355 065-245 025-105 155/30 .77 175-355 135-315 015-195 185/60 .34 020-200 145-325 183/30 35 115-.295 145-325 065-245 175-355 213/2 36 075-255 200/5 37 165-345 195/10 ~38 145-325 165-345 085-265 120/15 39 115-295 140/80 41 155-335 065-245 230/72 53 055-235 135-315 1.75-355 0.95-275 195/60 56 035-215 182/24 6 025-205 145-325 195/35 8 145-325 165-345 135/10 10 155-335 110-290 035-215 225/25 16 085-265 175-355 145-325 114/20 17 025-205 100-280 192/22

Tab . 6 . The four different systems of Joint-directions (I, II, 11I, IV) and dipofbeds.

-II7-

20 20 21 21

26 25 25 26

30 28 28

N N

32 31 31 32

Fig .50 . Selected stereographic pole diagrams and rose diagrams of joints . The majority of the sites were sketched for <10% ; 10--20% 20--30%, 30-40%, 40-50%, and more than 50% .

-II8® N

35 35 38

37 37 45

41 41 53 53

N N

43 43 69 69

Fig .51 . Selected of stereographic pole diagrams and rose diagrams of joints . The majority of the sites were sketched for <10%, 10-20%, 20-30%, 30-40%, 40-50%, and more than 50% .

-119-

are much more numerous, but have smaller lengths than the joints

in the clastic rock formations . Most of the joints are filled with calcite and some of them also display small dislocations in

the order of one to a few centimeters . They are cut by other joints of greater length, but lesser frequency . Common is also the presence of minor faults or joints, which have displacements of less than 10 cm.

From the diagrams of Skopelos, it is suggested that four major joint systems are developed . These systems are: I NW/SE 155°/335° - -WNW/ESE 115'/295° III NNE/SSW 005°/185° IV ENE/ SW 075°/255° Out of the above systems, only I appears in all locations while

the rest occur in fewer places, although in some of them the latter are the dominant ones . At present, it is not possible to dis- tinitly correlate the joints with other tectonic elements because geometrical considerations lead to different possibilities for the systems mentioned above . Moreover, is must be taken into account that the joints may have generated in response to different stress fields which changed with time.

3 .2 .2 .3 . Photolineations

It is known that in the different lithologic units variable networks of tectonic discontinuities are developed . For the accurate description of these discontinuities, their mapping was carried

out with the help of aerial photographs . The tectonic discontinu-

ities were placed on maps (Fig .52 and 53) after a ground check

0 1 2Km

Fig .52 . Map of ph®tobino tions from aärp1a®togr,aphs, so . 1s33000 3kopo1os island .

0 2Km

Fäg .53 . Map of ph®t®Iinoationo from alrph®tographs, sc . 1 :8000 Sk®p®l®o island . -I22 - of most of these data . For the transfer of the photolineations from the airphotographs to the maps, a zoom transfer scope was used . This instrument, minimizes the errors due to the orthopro- jectional data transfer to the topographic maps . Thus the placing of the photolineations on maps was effected in the most reliable way.

Photolineations are characteristic linear, or sometimes slightly curved elements of an area, deduced from single airphotographs of an area, from stereoscopic models, or from photomosaics . These data can be interpreted as faults, as geomorphological features, as hydrographic networks or even as linear arragements of vegetation . All these features are surface traces of subvertical joints or faults, i .e . general tectonic discontinuities . Very often differences in colour have indicated the linear or curvature form of the tectonic elements . Moreover, the resolution of the aerial photographs plays an important role . To avoid misinterpretations, two maps were drawn at the scales of 1 :33 .000 and 1 :8 .000. The first impression from these maps is that they contain photolineations of all directions . During the systematic classification with respect to their orientation, the photolineations, however, could be united to systems with distinct directions . These systems apparently have not only local character, but provide important information about the fault tectonism of a greater area. The existence of fault systems that traverse large areas with constant direction and frequency without being influenced from both the kind and the age of the rocks and from the folds, lead to the assumption of "general" or global tectonic systems as -123-

described by KNETSCH (1965), TAMM(1969), ROLAND (1971), and GAY (1973) . In Greece this must be true for the systems having NW/SE, NE/SW, N/S and E/W orientations, according to AUBOUIN (1971), IB-

BEKEN (1977), KRONBERG (1977), MEISSNER (1979) and TSOMBOS (1980) . From the comparison of photolineations from airphotographs at the scales of 1 : 33 .000 and is 8 .000, the average length of the photolineation can be mapped . In these airphotographs they are about 400 to 500 m long . As shown in table 7, the frequency of the lineations is three times higher at the scale of

1 :8000 and their length two times greater than at the scale of 1 :33000 .

1 :33000 1 :8000 UNITS N L N L Pelagonian 357 5545 1045 9976

Glossa 82 1258 414 2960

Palouki 165 2392 391 3914

Total 604 9195 1850 16650

Tab . 7 . Frequency (N) and length (Lo) of photolinations from the tectonic units of Skopelos, visible on the aerial photographs at 1 :33000 and 1 :8000.

All main directions derived from two aerial photographs scales coincide . The rose diagrams for each of these units differ, at each scale, in the system range : Thus the rose diagrams from aerial photographs at 1 : 33 .000 have a smaller range than those from the aerial photographs at 1 : 8 .000 (Fig .54 and 55).

In the Pelagonian unit and Mesoautochthonous series the rose diagrams shown the same peaks for both scales as well as in the Fig . 54 . Rose diagrams of photolineations derived from airphotographs sc . 1 :33000 . Pig . 55 . Rose diagrams of photolineations derived from airphotographs sc . 1 :8000 .

OI26-

Glossa unit . In the Palouki unit, finally the E/' and NE/SW directions also constitute distinct peaks at both scales . From the rose diagrams shown in Fig_54 and 55 four photolineation systems

are distinguished (Tab .8).

SYSTEMS PELAGONIAN GLOSSA PALOÜKI

1 :33000 1 :8000 1 :33000 1 :8000 1 :33000 1 :8000

I 125°/305° 125'/305' 075/255° 095°/275* 085°/265° 045°/225° II 075°/255° 075 ® /255° 005°/185° 155°/345° 045 ® /225° 095°/275° III 155°/335° 155°/335° 125°/305° 135'/305' 135°/315° 125°/305° IV 055°/235° 055°/235° 055°/235 ® 055°/235° 115 /335° 025°/205 TOTAL 1 :33000 1 :8000 I 165 ® /345° 090°/270° II 035°/215° 045°/225° III 135°/315° 025°/205

TV fl6.~i° /'7/iSv° 1'7R° /'1W Vl,lyJ f Gä . ..~ 1 J J / •JVW

Tab . 8 . Photolinations systems of Skopelos, derived from rose diagrams.

3 .2 .2 .4 . Summary and interpretation According to the measurements of the faults of 5kopelos island

and the interpretation of the rose diagrams, four different directions of fracturing were deduced : WNW/ESE . ICE/SW, ENE/WSW and NW/SE . The first-mentioned direction occurs in all three

units . It is represented by normal faults with displacements of

few . tens of meters . The study of joints merely revealed the ®I27

same maxima (WNW/ESE, NNE/SSW, ENE/WSW and NW/SE), and the same

is true for the photolineations (WNW/ESE, NNE/SSW, ENE/WSW and

NNW/SSE).

We may interpret the ENE/WSW systems as ac joint directions of

the large-scale folds of the Pelagoraian zone, which have a NNW

strike . The systems with northwesterly directions may represent

be joints which belong to the same fold system . The WNW/ESE sys-

tem can be related with the fold axes of NE/SW direction in many

places . The other systems may represent hkü elements in relation

to different fold systems.

To summarize, we may state a coincidence between these main

directions with the relevant directions of the tectonic disconti-

nuities mapped during the field work . The separate analyses of

the three fractural systems of faults, joints and photoline-

ations were compiled . In spite of some very small divergence, the results show a homogeneity which allows to group the directions

into four main fracture systems, NNW/SSE, NE/SW, NW/SE and

ENE/WSW . The latter one, ENE/WSW, is younger than the other and it is assumed that it could be the prolongation of the North -

Anatolian fault system . ®I28=

. Palaeogeography

The palaeogeographic evolution of the research area is studied

here based on our stratigraphic and sedimentological investigations and previous publications, such as AUBOUIN et al . (1970), KATSIKATSOS (1970), CELET and FERRIERE (1978), CLEMENT (1983), FERRIERE (1982), JACOBSHAGEN (1988, 1985), ROBERTSON (1989) etc. The area of Skopelos is composed of different tectonic units, the sediments of which were deposited in three different palaeogeographic spaces . These units are: - Pelagonian Unit

- Glossa unit - Palouki unit The Mesohellenic sequence covers the Pelagonian unit and with its main stratigraphic members the Palouki unit as well, whereas on the Glossa unit it is completely eroded today. The palaeogeographic evolution of these units is described in

this chapter and an attempt is made to correlate them and define their position within the palaeogeographic frame of the Helle- nides,

4 .1 . Pelagonian unit This unit occupies the largest part of Skopelos island and has

been part of the Pelagonian zone described by AUBOUIN (1959) .The stratigraphic sequence of this unit ranges from the Upper Palae- ozoic up to Palaeogene flysch sediments . From our results, we may assume the following palaeogeographic environment for the deposition of its stratigraphic members . ®I29

Skiathos saris

From this series, only the upper part is exposed, containing

Ladinian-Carnian fossils . At that time mainly clastic sediments were deposited . Included carbonate sediments yield a marine shal-

low water fauna . Thus we may assume a neritic environment for the upper part of the Skiathos series . This observation is in agree- ment with the ascertainments made in other areas of the Pelago- nian zone by various investigators, e .g . BERNOULLI & LAUBSCHER

(1972), and SIDERIS (1986) .This shallow sea, which already originated in Upper Palaeozoic times had covered large parts of the Hellenides . It is generally accepted that the clastic sediments deposited in this shallow sea were derived from Hercynian mountain ranges which were situated in the area east of the Rhodope

Massif. Pel=gonian dolomites Triassic During the Norian-Rhaetian period, carbonate sedimentation took p lace exclusively, resultin g in the formation of 500 m thick dolomites . They were deposited on a carbonate platform in supra- inter-subtidal areas and exhibit a sedimentation with lofer cyclothems . This type of carbonate sedimentation prevailed on very extended shelf areas bordering the Norian - Rhaetian Tethys to the south (e .g . Pelagonian and Parnassos platforms, Tripolitza,

Ionian and Pre- Apulian zones) . In all these areas we find a con- tinuous development from neritic conditions to an extended tidal region which characterizes the Upper Triassic carbonate platforms

(for further references see JACOBSHAGEN, : .1986) -130-

Jurassic As described above (2 .2), carbonate rocks of Jurassic age, which are widespread in the Pelagonian zone, (e .g . Orthrys . FERRIERE,

1982, Euboea, CLEMENT, 1983 and even nearby on Alonissos island,

according to new observations of V . Jacobshagen and the present author), could not be observed on Skopelos island, inspite of careful research . According to our opinion, the absence of Juras- sic carbonate deposits on Skopelos is due to intense erosion, which took place during the Lower Cretaceous, subsequent to the Eohellenic orogenic phase . This would mean the central area of the island had been strongly uplifted at that time . Anyway, Skopelos has been part of the Upper Triassic-Jurassic of the

Pelagonian zone (Pelagonian platform, KAUFFMANN et al ., 1975) . It is generally accepted today that this platform has separated the Almopias oceanic basin in the east from the Pindos trough or the

Maliac ocean (FLEURY, 1980, FERRIERE, 1982, VERCELY, 1984) in the

west respectively.

4 .2 . Glossa unit During the Upper Jurassic-Lower Cretaceous period the whole area of the internal Hellenides to which the Pelagonian zone belongs, was affected by the Eohellenic orogenesis (JACOESHACEH et al. 1976) . During this phase, the Almopias ocean closed and enormous ophiolitic masses accompanied by deep sea sediments and rocks from the margins of that ocean were obducted on the Pelagonian carbonate platform from the NE forming a cordillera there which was strongly uplifted and, subsequently, more or less intensely eroded . In many sites of this cordillera, erosion removed both -131-

fiche formations of the Eohellenic nappe and the carbonate forma-

tions of the Pelagonian zone beneath them . Skopelos island was an

area with an intense erosion as described above. Lithological studies of the Glossa unit have revealed that these

formations belonged to the Eohellenic nappe (chapter 3) . The metasediments were deposited in a deep sea . This conclusion is mainly based on the large percentage of siliceous beds occurring in the Glossa unit in the form of quartzitic intercalations which are interpreted as meta-radiolarites, the presence of siliceous bedding in the cipolinos marbles and the association with MORB- like metabasalts.

Based on the tectonic position of-the Glossa unit which was over-

thrust from the NE, it is possible to assume that the palaeogeo-

graphic space of that unit was an oceanic area located east of the Pelagonian platform, in other words in the area of the Almo- pias ocean.

4 .3 . Mesoautochthonous Cretaceous formations In the course of the Lower Cretaceous, uplift and erosion slowed down and were followed by a period of carstification of the Pela- gonian dolomites and lateritic weathering of the Eohellenic ophiolites . In Albian times the whole area subsided again below sea level and the scree of the foregoing cordillera was swept into the erosional depressions and carst pockets of the Mid- Cretaceous transgression, thus filling and smoothing the Lower Cretaceous relief.

Middle-Upper Cretaceous shallow marine sedimentation started with =I32-

thin-bedded limestones, probably of lagoonal origin, which were

followed by the recifal rudist limestones and, finally, by thin- bedded limestones again, which were interpreted as deposits of an open sea (e .g . JACOESHAGEN, 1983, JACOESHACEN & WALLBRECHER,

1984) . Such open-sea limestones have been found in many sites within the Pelagonian Zone, usually being of Maestrichtian age.

Flyech

During the period of Maestrichtian-Paleocene the deposition of the flysch may have started in the studied area . It marked, on the one hand, the maximum of subsidence and, on the other hand, pointed to an orogenetic development starting within the interior parts of the Hellenides and continously extending to the external areas.

In many sites of Skopelos island the flysch beds rest unconformably upon the Upper Cretaceous limestones, which in some places show a considerable decrease in their thickness thus indicating intense erosion . It is not known if the flysch deposition conti- nued on Skopelos.

4 .4 . Palouki Unit

As reported above (chapter 5), the stratigraphic sequence of the

Palouki unit was deposited conformably upon some remnants of the

Eohellenic nappe . The lower series, composed of thin-bedded limestones alternating with sandstones, phyllites, and chert layers, was possibly deposited on the margin of an epicontinental sea basin of considerable depth, into which clastic material was shed . As its upper parts grade continuously into the reef facies of the rudist limestones, we may conclude that the sea became -133- shallower . The further development within the Palouki unit was identical with that of the Mesoautochthonous. We summarize that considerable differences exist, however, between the Mesoautochthonous and the Palouki stratigraphic sequences when we consider the traces of Lower Cretaceous processes . Instead of a relatively extended period of uplift, erosion and weathering, which ended no earlier than in Albian time in the Mesoautochthonous sequence, we state that in the Palouki unit erosion of the Eohellenic nappe was very soon followed by a Lower Cretaceous transgression, without carstification and bauxite formation in between, and that this Lower Cretaceous sea was relatively deep . From these differences we derive that the Pal- ou-ki unit originated upon a epicontinental basin or upon the eastern slope of the Pelagonian platform and thus, was not so much influenced by the uplift of the Eohellenic cordillera .

®I34-

5e ary

Geological research on Skopelos island, accompanied by detailed

geological mapping, revealed that the island is composed of the following units: Pal agonian unit The stratigraphic sequence of this unit comprises the following series from bottom to top: The Skiathos series (Upper Palaeozoic-Carnian) consists of alternations of meta-sandstones, mica-calcite-schists, quartz-schists and chlorite-schists with intercalations of recrystallized limestone beds . It has been affected by low-grade metamorphism sense WINKLER (1976) . Near the top of the Skiathos series, a microfauna of Ladinian-Carnian age was found. The Pelagonian dolomites developed conformably upon the Skiathos series . According to microfossils, their age seams to be limited

to Norian-Rhaetian . The absence of Jurassic carbonate rocks within the Pelagonian zone of Skopelos island may be attributed to uplift and large-scale erosion, which took place in Lower Cre-

taceous times, subsequent to the Echellenic orogenetic phase. Microfacies analyses of the Upper Triassic dolomites determined 6 microfacies and showed that their dolomitization took place dur-

ing an early diagenetic sta ge . The Pelagonian dolomites were deposited in a shallow and restricted marine environment (lagoon), with tidal influences at least in parts of it . Alterna- tions of subtidal dolomites with inter- to supratidal ones were

observed, showing cyclic depositional sequences. This type of Upper Triassic carbonate sedimentation characterizes

-135-

almost the whole southern continental margin of the Tethys, including the regional Pelagonian and Parnassos platforms of the Hellenides.

Glossa unit This unit consists of a volcanosedimentary series, which belonged to the Eohellenic nappe, contrary to the opinion of all former authors, who considered the Glossa unit to have been part of the

Hercynian basement . Our hypothesis is proved by both tectonic observations in the field and lithological and geochemical arguments . The Glossa unit was overthrust directly upon the Skiathos

series . Small remnants of the Eohellenic nappe have been located, furthermore, at the base of the Palouki unit, upon the Pelagonian dolomites of the Loutsa area and, finally, in the Aevithi and Nisei areas, beneath the Mesoautochthonous Upper Cretaceous limestones.

The Glossa unit is composed of metabasalts, serpentinites, mica- chlorite-calcite schists, chlorite-mica-quartz schists, phyllites

snis~es^a3~ r, r3 r r-~n l n n 'rn $i7r~ §o P1'.AY°.dReneGeG pJl_ .. i g i marbles, .e,. w, a .. . According ~ .v ...as+Jaa . sNlsAVdbiA .bd[A{jV16GOGS7~ these rocks have been affected by a low-grade metamorphism

(greenschist fades) . The geochemistry of the Eohellenic metabasalts indicates tholeiitic affinities with a MO14B-like character. Fragments of Eohellenic schists and ophiolites within the Middle Cretaceous bauxites testify to an Upper Jurassic - Lowermost Cre- taceous metamorphism of the Eohellenic rocks. Mesoautochthonous

The Mesoautochthonous complex comprises Lower Cretaceous lateri-

tes and bauxites . Middle and Upper Cretaceous limestones and flysch, probably of Palaeocene age . This sequence covers discon-

®I 36=

formably the Pelagonian unit, together with some small relics of the Eohellenic nappe, but was nowhere found upon the Glossa unit. Its stratigraphical sequence is the following (from bottom to

top) : The metalaterites and metabauxites occur almost everywhere between the strongly eroded Pelagonian dolomites and the overlying Upper Cretaceous limestones . The laterites and bauxites are related to metabasalts of the Glossa unit, which is also suppor-

ted by geochemical analyses . Conglomerates of the Cretaceous transgression are widely distributed with thickneses ranging from

a few centimeters up to 100 m . Their pebbles are dolomitic, with varying size, and their matrix is calcitic or sometimes lateritic . These conglomerates were deposited upon the deeply eroded Pelagonian dolomites ; discoveries of microfossils within their matrix testify to an Upper Albian (draconian) age. The large differences in thickness, in the forms and sizes of pebbles, and their varying degree of sorting indicate the palaeogeographic conditions.

Tina ri- -. rv. aFar®nIi rT t i~F 1 irrsF+~i Wraps ea4ß-3nAv overlie the con-

glomerates conformably or rest even unconformably upon the Pela- gonian dolomites, their thickness varying between a few meters

and 200 m . The lower members of these limestones are locally thin bedded and grade towards the top into unbedded rocks, which are

in tP Srn ft -:ed by platy limestones at the top . On the whole, the facies of the Upper Cretaceous limestones vary widely . The lower thin-bedded members (Cenomanian) were deposited within in a

lagoonal environment, whereas the thick-bedded to unbedded rocks

(Turonian) had a recifal origin . .Pinally, the upper platy limestones were deposited in a deeper part of the shelf . ®I37-

The flysch, being probably of Lowermost Tertiary age, covers the

Cretaceous limestones unconformably . It comprises metapelites,

metasandstones, recrystallized calciturbidites, quartzites and conglomerates, indicating the maximum of subsidence and, synchronously, the beginning of the Mesohellenic orogenic processes within the internal Hellenides . Its thickness is about 150 m.

Palouki unit This unit is overthrust on the Mesoautochthonous flysch . It com-

prises Cretaceous and Lower Tertiary sediments with remnants of the Eohelilenic nappe (serpentinites, metabasalts and schists) at their base . The stratigraphical sequence of the Palouki unit

starts with the Lower Series composed of thin-bedded limestones, calciturbidites, sandstones and phyllites alternating with chert intercalations . New findings of micro- and macrofossils in this formation indicate a Lower Cretaceous age without pre cluding the Upper Jurassic . This formation was probably deposited in a deeper epicontinental basin or upon a continental slope. The Lower Series is followed by Upper Cretaceous rudist limestones, white in colour, slightly recrystallized, and not exceeding a thickness of 120 m . Finally, small relics of Palaeogene flysch are preserved above the limestones . Both the rudist limestones

and the flysch correspond well with the equivalent members of the Mesoautochthonous sequence. All rocks of the Palouki unit have suffered a low-grade metamorphism and were deformed to large-scale recumbent folds . There- fore, the Palouki unit must have been covered by a pile of Meso- hellenic (Eocene) nappes, which were eroded later on . -138-

Structural Geology

The Pelagonian and Mesoautochthonous complex form an anticlinorial structure in the central part of the island, exhibiting large-scale cross-folding . The Glossa unit was overthrust upon the Pelagonian dolomites or directly upon the Skiathos series . The latter situation might have originated by shearing during the Eohellenic obduction or even during the Mesohellenic (Eocene) collision . The overthrust of the Palouki unit can be followed across the island from the bay of Skopelos Town in the northeastern part to Cape Stafylos in the southwest of Skopelos island.

The three main systems of the directions of fold axes are NNE/SSW, WNW/ESE, and ENE/WSW . It is likely that the first two systems were the result of only one diastrophism and are caused by phenomena of anisotropy . The third system is clearly younger than both of the first systems, as it refolds each of them . It has the deformed the Palaeogene flysch, obviously during the Eoc- ene (Mesohellenic) orogenesis . The results of the compilation of the separate analysis (faults, joints and photolineations) show a homogeneity which allows to group the directions into four main fractural systems : NNW/SSE, NE/S, NW/SE, and ENE/WSW . The last one is younger than the others, and it is assumed that it could be the prolongation of the North Anatolian fault system.

Pal eogeography Pelagonian Unit : The upper part of the Skiathos series (Ladinian-

Carnian) was de-posited in marine shallow water . The transition from the Skiathos series to the Pelagonian dolomites (Norian- -139-

Rhaetian) is gradational . The Pelagonian dolomites are deposits

of a very shallow restricted sea indicating inter- to supratidal

environments . They have been part of the Pelagonian platform.

Glossa Unit : This unit belonged to the Eohellenic nappe . The

nietabasalts of the Glossa Unit show a MOPE-like character, and

the associated metasediments have been deposited in a hemipelagic

or even pelagic environment . Thus, this unit might have origi-

nated within a marginal or even oceanic basin northeast of the

Pelagonian platform, i .e ., within the Tethys ocean proper.

Mesoautochthonous : In the course of the Lower Cretaceous, uplift

and erosion of the Pelagonian dolomites and lateritic weathering

of the Eohellenic ophiolites taken place . In Albian times, they

subsided again below sea level . The character of the Cretaceous

carbonate sequence testifies to a development from a lagoonal

stage to open shelf conditions (rudist limestones) and, finally.

to a relatively deep marine basin . The deposition of the flysch points to an orogenetic event during the ?Maastrichtian-Paleocene

interval, which started within the interior parts of the Helle- nides and extended continuously to the external areas.

Palouki unit : The stratigraphic sequence of the Palouki unit was deposited conformably upon some remnants of the Eohellenic nappe.

The Lower Series was deposited on the margin of an epicontinental sea basin or upon a continental slope . The upper parts continue into the reef fades with rudist limestones followed by the deposition of flysch . The Palouki unit originated upon the eastern slope of the Pelagonian platform and thus, was not so much influenced.,bythe uplift of the .Eohellenic .cordillera .

-140-

Zusammenfassung Geologische Forschung auf der Insel Skopelos, begleitet von detaillierter geologischer Kartierung, zeigte, daß die Insel von folgenden Einheiten aufgebaut ist: Pelagonische Einheit Die stratigraphische Folge dieser Einheit umfaßt von unten nach oben folgende Serien: Die Skiathos - Serie (Oberes Paläozoikum - Karr) besteht aus Wechsellagerungen von Metasandsteinen, Kalkschiefern, Quarzschiefern und Chloritschiefern mit zwischengeschalteten rekristallisierten Kalkbänken . Sie wurden von einer griinschieferfaziellen Metamorphose erfaßt . Am Top der Skiathos Serie wurde eine Mikrofauna des Ladin Kann gefunden Die Pelagonischen Dolomite entwickelten sich konkordant aus der Skiathos Serie . Mach Mikrofossilien scheint das Alter auf Nor Rhät beschränkt zu sein . Das Fehlen jurassischer Karbonate in der Pelagonischen Abfolge der Insel Skopelos wird durch einer Hebung mit großflächiger Abtragung bedingt, die während der Unter-Kreide stattfand und der Eohellenischen Phase folgte. Durch Mikrofazies-Analysen obertriassischer Dolomite wurden sechs Mikrofazies-Typen bestimmt und gezeigt, daß die frühdiagenetisch erfolgte . Die Pelagonischen Dolomite wurden in einer flachmarinen, eingeschränkten Lagune abgelagert ; Teile waren tidal beeinflußt . Zyklische Wechsellagerungen subtidaler Dolomite mit inter- bis supratidalen Dolomiten wurden beobachtet . Dieser Typ obertriassischer Karbonatsedimentation charakterisiert fast den gesamten südlichen Kontinentalrand der Tethys, einschließlich der Pelagonischen und der Parnass - Plattform der Helleniden .

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Glossa ® Einheit Diese Einheit besteht aus vulkanosedimentären Serien, die zur Eohellenischen Decke gehören, im Gegensatz zu Meinungen früherer Autoren, die sie als Teil des hercynischen Grundgebirges ansahen . Unsere Hypothese wird durch tektonische Feldbeobachtungen und lithologische sowie geochemische Argumente gestützt . Die Glossa Einheit wurde direkt auf die Skiathos Serie überschoben . Kleine Reste der Eohellenischen Decke wurden überdies an der Basis der Palouki ® Einheit auf Pelagonischem Dolomit des Loutsa Gebietes und zum anderen in den Regionen von Revithi und Nissi unter den Oberkreide Kalken des Mesoautochthons festgestellt. Die Glossa m Einheit besteht aus }ietabasalten, Serpentiniten, Glimmer-Chlorit®Kalkschiefern, Chlorit®Glimmer-Ouarzschiefern, Phylliten und dünnbankigen Marmoren . Aufgrund ihrer Mineralur Paragenese wurden die Gesteine von einer niedriggradigen Metamorphose geprägt . Geochemisch zeigen die eohellenischen

Metabasalte eine tholeiitische Affinität mit MORE ® ähnlichem Charakter. Fragmente der eohellenischen Schiefer und Ophiolite in den mittelkretazischen Bauxiten zeigen an, daß die Metamorphose der

eohellenischen Gesteine in späten Malm oder in der tw i efens u a s Unterkreide erfolgt ist. esoautcchthcn Der mesoautochthone Schichtkomplex besteht aus unterkretazischen Lateriten und Bauxiten, mittel- und oberkretazischen Kalken sowie aus Flysch Sedimenten, letztere wahrscheinlich paleozänen Alters . Diese Folge überlagert diskontinuierlich die Pelagonische Einheit sowie einige sehr kleine Relikte der

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Eohellenischen Decke, aber sie wurde nie auf der Glossa Einheit gefunden . Die stratigraphische Sequenz ist wie folgt (von unten nach oben): Die Metalaterite und Metabauxite kommen fast überall zwischen den stark erodierten Pelagonischen Dolomiten und den oberkretazischen Kalken vor . Die Laterite und Bauxite sind aus der Verwitterung von Metabasalten der Glossa - Einheit hervorgegangen, was durch chemische Analysen gezeigt wurde. Konglomerate der kretazischen Transgression sind weit verbreitet . Sie variieren in ihrer Mächtigkeit zwischen wenigen Zentimetern und 100 m . Ihre Gerölle bestehen aus den Pelagonischen Dolomiten, ihre Matrix ist calcitisch oder manchmal lateritisch . Diese Konglomerate wurden über den tief erodierten Pelagonischen Dolomiten abgelagert ; Funde von Mikrofossilien in der Matrix zeigen ein Oberalb Alter (Vraconium) an. Die großen Unterschiede in Form und Größe der Gerölle sowie der unterschiedliche Sortierungsgrad spiegeln das Paläorelief wieder. Die oberkretazischen Rudistenkalke überlagern die Konglomerate entweder konkordant oder sie lagern diskordant über Pelagonischen Dolomiten . Auch ihre Mächtigkeit schwankt zwischen einigen Metern und 200 m . Die tiefen Teile dieser Kalke sind oft dünnbankig und gehen nach oben in massige Gesteine über, die wiederum von plattigen Kalken abgelöst werden . Im ganzen variiert die Fazies der Oberkreide ® Kalke starke Die unteren gebankten Anteile (Cenoman) wurden in . einem lagunären Bereich abgelagert, die .massigen . Gesteine (Turon) sind als . .Riff-

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Sedimente anzusprechen und die oberen plattigen Teile repräsentieren einen tieferen Bereich des Schelfs. Der vermutlich alttertiäre Flysch überlagert die Kreide - Kalke diskordant . Er umfasst Metapelite, Metasandsteine, rekristallisierte Kalkturbidite, Quarzite und Konglomerate und zeigt das Maximum der Subsidenz und gleichzeitig den Beginn der Mesohellenischen Orogenese in den inneren Helleniden an . Seine Mächtigkeit beträgt ca . 150 in. Palouki ° Einheit Diese Einheit ist auf den mesoautochthonen Flysch überschoben. Sie enthält Sedimente der Kreide und des Alttertiärs mit Resten der Eohellenischen Decke (Serpentinite, Metabasalte und Schiefer) an der Basis . Die stratigraphische Abfolge beginnt mit der Unteren Serie, die aus dünnbankigen Kalken, Calciturbiditen in Wechsellagerung mit Sandsteinen, Phylliten und Hornsteinlagen bestehen . Neue Mikro- und Makrofossilfunde in dieser Formation ergaben ein unterkretazisches Alter ; aber auch Oberjura kann nicht ausgeschlossen werden . Diese Formation wurde in einem tieferen epikontinentalen Becken oder auf einem Kontinentalhang abgelagert. Die Untere Serie wird von weißen, etwas rekristallisierten Rudistenkalken überlagert . Deren Mächtigkeit übersteigt nicht 120 m . Über den Rudistenkalken sind noch kleine Relikte paläogenen Flysches erhalten . Die Rudistenkalke unter dem Flysch der Palouki - Einheit stimmen gut mit den äquivalenten Schichten des Mesoautochthons überein Alle Gesteine der Palouki ® Einheit erlitten eine niedriggradige Metamorphose und wurden in großmaßstäbliche liegende Falten gelegt . Daher muß die Palouki Einheit von einem mächtigen

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Stapel mesohellenischer Decken überlagert gewesen sein, die später erodiert worden sind. Strukturgeologie Der Pelagonische und der Mesoautochthone Komplex bilden im Zentralteil der Insel ein Antiklinorium mit Kreuzfaltung in großem Maßstab. Die Glossa Einheit wurde auf die Pelagonischen Dolomite oder direkt auf die Skiathos Serie überschoben® Die letztere Situation könnte bei Scherungsvorgängen während der Eohellenischen Obduktion entstanden sein oder auch während der mesohellenischen Kollision im Eozäna Die basale Überschiebung der Palouki Einheit kann über die ganze Insel von der Bucht von Skopelos ira NE bis Kap Stafylos im SW verfolgt werden Die drei Hauptrichtungen der Faltenachsen sind NNE/SSW, WNW/ESE und ENE/WSW . Es ist anzunehmen, daß die beiden ersten Systeme das Ergebnis nur eines Diastrophismus und möglicherweise durch Phänomene der Anisotropie bedingt sind . Das dritte System äst deutlich jünger als die beiden anderen, da es beide überprägtm Alle Faltensysteme haben den paläogenen Flysch verformt, offensichtlich während der mesohellenischen Oragenese . Bei der Vermessung vov Störungen, Klüften und Fotolineationen ergaben

sichY, weitgehende Obereinstimmungen . Ihrew RichtunRichtungengen könne! wie folgt in vier Hauptgruppen eingeteilt werden : NNW/SSE, NE/SW,NW/SE und ENE/WSWa Letztere ist jünger als die anderen, und es ist anzunehmen, daß sie in Zusammenhang mit der Nördägäischen Störungszone gebildet wurden . Dieses Lineament stellt eine Verlängerung des Nordanatolischen Störungssystems darin

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Paläogeographie Pelagonische Einheit Der obere Teil der Skiathos Serie (Ladin Karn) wurde . in einem flachen Meeresbereich abgelagert . Nach oben geht die Skiathos Serie kontinuierlich in die Pelagonische Dolomite (Nor ® Rhät) über . Diese sind im inter- bis supratidalen Sedimentationsbereich eines sehr flachen, eingeschränkten Meeresgebietes abgelagert worden . Sie bildeten einen Teil der Pelagonischen Plattform. Glossa Einheit Diese Einheit gehört der Eohellenischen Decke an . Die Metabasalte der Glossa - Einheit weisen einen MORS - ähnlichen Charakter auf, Die assoziierten Metasedimente sind als hemipelagisch oder sogar pelagisch zu betrachten . Daher könnte die Palouki - Einheit am nordöstlichen Hang der Pelagonischen Plattform gegen das Tethys - Becken beheimatet gewesen sein. esoatochthon Während der Unterkreide fand eine Hebung mit Erosion der

S - A _ _° L ! _ L _ .Z ~ Pelagonischen Dolomite sowie die ~a~er ~~ ~ sc:~ae Verwitterung dere Eohellenischen Ophiolite statt . Im Alb morde das Gebiet wieder unter den Meeresspiegel abgesenkt . Die Facies der oberkretazischen Karbonatfolge belegen eine Entwicklung von einer Lagune zu einem offen marinen Schelf mit Rudistenkalken und schließlich zu einem relativ tiefen Meeresbecken . Die Ablagerung der Flysch e sedimente deutet einen Faltungsprozess während des (?) Maastricht bis Paläozän an, der in den inneren Teilen der Helleniden begann und sich kontinuierlich nach außen verlagerte

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PLÄKES

PALOUKI UNIT

OUÄTERN, TERTI&RY

Alluvia Flysch deposit

UPPER CRETACEOUS 'Marshy coastal Upper Cnztocooos - imesLones p ^~ Talus c . .A C SA scree LOWER CRETACEOUS

Fluvial Lower series (Alternations of limestones, mcLa- sandStones and schists) Geologi bDundur ~ pr.. AA Metöbasalts ~~ :' r~':l

J_ Strike of beds Serpentinites Fault

^ ^-~^- Overth

C-' ';rs ~>> S S C~:~ CTI N

CHLIA DHELFI KAPRISA PLAKES NW SE

500 m A 0

LEGEND

MESOAUTOCHTII0N10US GLOSSA UNIT PULAGONIAN UNIT PALOUKI UNIT

QUATERNARY TERTIARY UPPER TRIASSIC TERTIARY

•/ /,/,/, AAAAAAA,AAAAAA '/////i///////// AAAAAAAhI.AAAA Pelagonian // ///,~,y/////l AAAAAn ~AAAAA Alluvial ///// /A .U / AAAAAA~t1AAAAA Metabasalts .,/ ,/ / ! lysch AAAAAAA,.AAAAAA dolomites Flysch deposits

UPPER PALEOZOIC _ , TO CARNIAN UPPER CRETACEOUS . Marshy silt and G# CENOMANIAN-TURONIAN V v V V V SVV Vry~Vp/VV V V V' V ~ Serpentinites :': coastal sand VvV~V SVVVVVVVVV V Skiathos series ..- n Upper Cretaceous Upper Cretaceous (Metaclastic rocks ~ ~~~w imestones .rrr.r~41 limestones f with limestones in- ~.~ . .. .r g,Itt 1)>'ip :iränöö ©i Talus cones and aooc+_I~ono°rta11CI.vo cn /^ OOOADOE7 Cipolines Tm tercalations) 4 ~H ~~± s ~ scree ~ ~ P1 ~ öirJllä4nl°olWZI 7IL1[iL71O1[ätall LOWER CRETACEOUS

Eluvial mantle UPPER AL3IAN Schists Lower series I UI? 00 DU4 0 0000 ml )UpAUUO941tfUUp g reccio- Im ~OrYm (Alternations of JbOUAKU'U U99 . Y~mmmll]76L pIROOJl1 )UOOA4 49A ~ 6p6UM conglomerates dml9y~ fYmll limestones, meta- )000066uU0UU4 1WI mml~m mmWml sandstones and schists) Geological

boundary Fe,Ni-laterites n .AAAi.r A. .A ;AA, , A :,A AApI;aA . Metabasalts and bauxites

i Strike and dip of beds ;°vv V~~IVYVVwvwl ;~~vYV ~Y~Y~YyV° Serpentinites v v Fault and its probable extension L V V V V VV V'

-L Overthrust and its probable extension

GEOLOGICAL MAP OF SKOPELOS ISLAND SCALE 1 : 50000 BY DION . MATARANGA

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JüI-2684 October 1992 ISSN 0366-0885