The igneous rocks of Greece

Transcription

1 The igneous rocks of Greece The anatomy of an orogen by Georgia Pe-Piper David J.W. Piper With 288 figures and 11 tables 2002 GEBRUDER BORNTRAEGER BERLIN STUTTGART

2 Preface Abbreviations and acronyms Contents 1 Introduction Igneous rocks within the Hellenide orogen Organization of the book Introduction Rock and mineral nomenclature Outline of the geology of Greece Introduction A brief history of geological studies in Greece Terranes of the Hellenides Pre-Mesozoic continental basement Tectono-stratigraphy of the Hellenides Mesozoic rifting and sedimentation The ophiolites Alpine orogenesis Neogene extension and block rotation Cenozoic igneous activity The present geophysical fields Plate tectonic evolution of Greece 21 2 Late Paleozoic plutonism and volcanism Introduction: the Hercynian basement of Greece Plutons in the Pelagonian zone of Thessaly and western Macedonia: type example Regional structural setting Geology of the Verdikoussa pluton Geology of other plutons of the Pelagonian zone Probable Hercynian plutonism in northeastern Greece Vardar zone Serbo-Macedonian and Rhodope zones Basement rocks of western Anatolia Hercynian basement rocks in southern Greece Cyclades islands 33 V XVI

3 VIII Contents Crete, Dodecanese and the Peloponnese Attiki, Othris, Evia and Chios Geology of volcanic rocks of Karakaya suture zone Introduction Geological setting of Chios Geological setting of Lesbos The possible extension of the Karakaya suture to Greece Petrography and geochemistry Petrography of the granitoid rocks Petrography of the mafic plutonic rocks Geochemistry of the granitoid rocks and associated mafic rocks Geochemistry of the Hercynian amphibolites Geochemistry of the Paleozoic volcanic rocks of Chios Synthesis of the regional setting of Carboniferous plutons 51 3 Triassicriftingand volcanism General geologic history of the early Mesozoic of Greece Introduction: the creation ofneotethys Plate-tectonic interpretation oftriassic rifting Permian-Triassic rifting in Greece Othris and north Evia: a type example Introduction Geologic setting of the early to mid-triassic early-rifting volcanic rocks Geologic setting of the Carnian volcanic rocks of Othris Geologic setting of Plate Triassic - PJurassic ocean-floor of Othris and Evia Petrography and geochemistry of the early to mid-triassic alkaline volcanic rocks :: Petrography and geochemistry of mid-to late Triassic subalkaline volcanic rocks Petrography and geochemistry of the late Triassic early Jurassic ocean floor rocks ; Regional implications of the Othris-Evia transect Geology oftriassic volcanic rocks of Apulia on the margin of the Pindos ocean Phyllite-Quartzite Unit Western margin of the Pindos zone Pindos zone of Crete and the south Aegean islands Triassic volcanic rocks within melanges Kerassies Milea ophiolite zone Parnassos zone ?Triassic meta-igneous rocks of the Cyclades, south Evia and Thessaly Introduction Basal Unit of the Cyclades: volcanic rocks Basal Unit of the Cyclades: granites Intermediate Unit of the Cyclades 80

4 Contents IX The Styra-Ochi unit of southern Evia The blueschist units ofthessaly Geology of Triassic volcanic rocks of Pelagonia The Pelagonian nappes of mainland Greece Upper Unit of the Cyclades and Pelagonian nappes of the eastern Aegean islands Geology oftriassic volcanic rocks of the Vardar and Serbo-Macedonian zones Introduction Circum-Rhodope belt Summary Petrography and geochemistry Introduction Subalkaline basaltic andesite and related rocks Basalt and andesite of shoshonitic or calc-alkaline affinity Alkaline basalt MORB-related rocks Subalkaline rocks with boninitic affinities Rhyolite Regional synthesis Stratigraphic and paleogeographic distribution of volcanic rocks The relationship oftriassic volcanism to rifting and mantle plumes The role of subduction and back-arc spreading in the genesis of Triassic volcanic rocks Jurassic Pindos ocean basin: ophiolites and melanges Introduction: the western ophiolite belt of Greece Type example: the Vourinds and Pindos ophiolites Geology of the Vburinos ophiolite Geology of the Pindos ophiolite Petrography and geochemistry of the Vourinos and Pindos ophiolites The significance of sub-ophiolitic melange Emplacement of the Vourinos and Pindos ophiolites The western Jurassic ophiolite sequences and related rocks of the Pelagonian zone Introduction Ophiolites of northwestern Thessaly and western Macedonia Ophiolites of Othris Ophiolites of Evia and Pelion Ophiolites of Beotia and Attiki Ophiolites of Argolis Melanges beneath the western ophiolite belt The record of volcanism in the foreland basin created by the obducting ophiolites Evidence for ophiolites in detrital conglomerates of the external Hellenides 131

5 X Contents Tectonic slices in die Pindos basin of the Peloponnese Clay-mineral and manganese evidence for volcanic activity Ultramafic and mafic rocks of the lower nappe of the Phyllite-Quartzite unit Meta-ophiolites in the Intermediate Unit of the Attico-Cycladic complex and possible correlatives inthessaly Introduction Cyclades Blueschist unit ofthessaly The "Ophiolite nappe" of Crete, the south Aegean islands, and the upper unit of the Cyclades Introduction Crete and Gavdos Karpathos and Rhodos Ophiolites of the Upper Unit of the Cyclades Petrography and geochemistry of die western ophiolite belt Volcanic and dyke rocks Plutonic rocks Ultramafic rocks Chromite Hydrothermal mineralization Synthesis: distribution and origin of Jurassic oceanic igneous rocks Oceanic environments revealed by geochemical studies What oceans did the ophiolites come from? Mesozoic ocean crust of northeast Greece Tectonic and stratigraphic setting of northeast Greece Mesozoic igneous rocks of the Vardar zone Almopias subzone: geological summary Ophiolites of the eastern Almopias subzone Dismembered ophiolites of the central Almopias subzone Ophiolites of the western Almopias subzone Eastern Thessaly and Pelion Eohellenic unit of the islands of the northwest Aegean Sea Palkon subzone Peonias subzone: overview Guevgueli ophiolites Granites of the Peonias subzone Stip-Axios massif Thessaloniki ophiolites Oreokastro ophiolite Aspro Vrissi Formation Chortiatis magmatic suite of nordiern Chalkidiki Chortiatis magmatic suite of Sithonia Sithonia ophiolitic rift complex The circum-rhodope belt in Samothraki 178

6 Contents XI The circum-rhodope belt of southeastern Thrace Ophiolites of the northeast Aegean Mesozoic igneous rocks of the Rhodope and Serbo-Macedonian zones Outline of the geology of the Rhodope and Serbo-Macedonian zones Geology of meta-igneous rocks of the Rhodope zone Geology of meta-ophiolites and amphibolites of the Serbo-Macedonian zone Granites of the Serbo-Macedonian zone Petrography and geochemistry of Mesozoic igneous rocks of northeastern Greece Ophiolitic rocks of the Almopias subzone Ophiolitic rocks of the eastern Peonias subzone Guevgueli ophiolites Sithonia ophiolites Ophiolitic rocks of Samothraki and Thrace Ophiolitic rocks of the Rhodope and Serbo-Macedonian zones Ophiolitic rocks of Lesbos Subduction-related volcanism of the Pa'ikon subzone Chortiatis suite Jurassic dykes and granites of the Vardar zone Older granites of the Serbo-Macedonian zone Regional synthesis Regional tectonic framework The ophiolites of the Vardar zone and circum-rhodope belt Tectonic evolution of the Serbo-Macedonian and Rhodope zones A plate tectonic model Cretaceous ophiolites and subduction in central and south Greece Late Cretaceous ophiolitic rocks Late Cretaceous oceanic crust in central Evia Possible latest Cretaceous oceanic crust in the Sporades, Pelion, Skyros and Macedonia ; The Ermioni Complex of Argolis Cretaceous oceanic crust in the south Aegean islands Stratigraphic distribution of manganiferous sedimentary rocks in the Pindos basin Petrography and geochemistry of the ophiolitic rocks Cretaceous subduction/accretion complexes Crete Cyclades Possible evidence of Cretaceous subduction in the blueschist belt of Evia and the Cyclades Petrography and geochemistry of the subduction complexes Regional syndiesis 236

7 XII Contents 7 Early Tertiary plutonism and volcanism of Macedonia and Thrace Cenozoic evolution of the Aegean region Introduction Regional evidence for extension Pre-Oligocene plutons of the Serbo-Macedonian and Rhodope zones Introduction Sithonia plutonic complex: a type example of Eocene plutonism in Chalkidiki Ouranopolis and other Eocene plutons of Chalkidiki The Elatia-Skaloti pluton Other plutons of uncertain age Oligocene plutonism Introduction Xanthi pluton: type example of Oligocene plutonism Northeastern Vrondou pluton Smaller Rhodope plutons Plutons of central Thrace Oligocene porphyry intrusions of the Serbo-Macedonian zone Oligocene volcanic rocks of the Rhodope zone and Thrace Early Miocene extension-related plutonism Kavala pluton Southwestern Vrondou pluton Petrography and geochemistry Eocene plutons of Chalkidiki Elatia - Skaloti pluton Oligocene plutons and volcanic rocks Miocene plutons and hypabyssal rocks Isotopic data Petrogenesis of the Eocene-Miocene igneous rocks Regional synthesis Early Miocene volcanism of the northeast Aegean Lesbos: a type example Regional geologic setting Geology of Lesbos Stratigraphic and spatial variations in geochemistry of Lesbos Isotope geochemistry of Lesbos Mineralogy of the volcanic rocks of Lesbos The geology of other volcanic centres Limnos Agios Evstratios Samothraki Anatolia Petrography and geochemistry of the other volcanic centres Volcanic rocks 301

8 Contents XIII Plutonic rocks Regional synthesis Miocene plutonism in the Cyclades The general setting of Miocene igneous activity in the Cyclades Introduction The metamorphic history of the Cyclades The central Cyclades granites Geology of Naxos Petrography and geochemistry of Naxos Geology and structure of Delos Petrography and geochemistry of Delos Tinos Mykonos Paros and adjacent islands Ikaria The western Cyclades granodiorites Serifos Lavrion The eastern Cyclades monzonites Kos Samos Regional variation in the plutonic rocks of the Cyclades Synthesis of age of plutonism Regional trends in petrography and geochemistry of the plutons Regional trends in isotopic variation Mid-Cenozoic minor volcanism in the South Aegean Oligocene ash in Rhodos..; Rhyolitic pyroclastic rocks of Miocene-Pliocene age The record of volcanism from tephra deposits 342, 9.7 Synthesis: petrogenesis and tectonic setting Petrogenetic synthesis : Tectonic setting Miocene-Quaternary volcanic rocks of central and northern Greece Introduction: the Aegean Sea as a back-arc basin Geology of individual volcanic centres Mid-Miocene of the eastern Aegean Mid-Miocene of the central Aegean Upper Miocene of the southeast Aegean Sea Euboecos The north Aegean Sea and Macedonia Western Anatolia and eastern Thrace Geothermal activity Petrography and geochemistry 359

9 XIV Contents General geochemical character of the back-arc volcanic rocks Mineralogy Isotopic variability Basalt Trachyte and related rocks Adakite The chronological sequence of lavas Synthesis: petrogenesis and tectonic setting Petrogenetic synthesis Tectonic interpretation of regional variability The South Aegean Arc The geologic setting of the major volcanic centres Introduction The marine tephrochronology record Volcanic centres of the Saronic Gulf The Milos group Santorini Volcanic centres of the southeast Aegean The relationship of tectonism and volcanism Petrography and geochemistry General geochemical character of the volcanic rocks of the South Aegean Arc Isotopic variability in the volcanic rocks of the South Aegean Arc Petrological evolution through time at centres of the Saronic Gulf and Milos Petrological evolution through time at Santorini Petrological evolution through time at Nisyros and Kos.i The evolution.and eruption of magma chambers Processes of geochemical evolution Synthesis: Petrogenesis and tectonic setting : Petrogenetic synthesis The role of subduction and extension Synthesis Introduction General themes in the geological evolution of Greece Late Paleozoic assembly of continental fragments Permian-Triassic rifting Mesozoic - Cenozoic history of the Atlantic Ocean and its control on events in Greece Ophiolites Ocean closure and collision of continental fragments Cenozoic extension and southward migration of the subduction zone Geochemical and isotopic evolution of the sub-continental lithospheric mantle 441

10 Contents XV Pb isotopes Sr and Nd isotopes Regional interpretation of isotopic variability Economic and societal aspects of igneous activity Mineral resources Geothermal resources Radon and other geomedical hazards Volcanic risk 447 References 448 Appendix Appendix Appendix General Index 562