Structural Evolution of the Western Gulf of Corinth, Greece: a Stratigraphic Analysis of Early Phase Continental Rifting

Structural Evolution of the Western Gulf of Corinth, Greece: A stratigraphic analysis of early phase continental rifting

Rebecca Bell Lisa McNeill Jon Bull Tim Henstock

National Oceanography Centre, Southampton University of Southampton

AGU Fall Meeting, San Francisco, 2006

Bell, McNeill, Bull, Henstock (NOC,S) Evolution of the W. Gulf of Corinth December 2006 1 / 12 Introduction Presentation Outline

20˚ 25˚ 30˚

North Anatolian fault 1 Introduction 40˚

Gulf of Corinth 2 Stratigraphy

3 Basin Geometry and Evolution Hellenic Trench 35˚

4 Rift History Discussion NEIC earthquake catalogue 20˚ 25˚ 30˚

−5500−4500−3500−2500−1500 −500 0 500 1000 1500 2000 2500 3000 elevation (m)

Bell, McNeill, Bull, Henstock (NOC,S) Evolution of the W. Gulf of Corinth December 2006 2 / 12 Introduction Gulf of Corinth Tectonics The Gulf of Corinth

22˚00' 22˚30' 23˚00' 38˚30'

Itea Nafpaktos Antikyra Trizonia Erateini Galaxidi Major active faults

−1000 0 1000 2000 Straits of m Rion Patra −200 Domvrena Aigion Eliki Gulf of −400 20˚ EURASIAN 25˚ 30˚ Corinth PLATE Greece Akrata −800 40˚ Alkyonides Gulf Turkey ANATOLIAN Xylokastron−600 PLATE Perachora 38˚00' Kiato

km 35˚ AFRICAN PLATE 200 km Corinthos 0 10 20

Bell, McNeill, Bull, Henstock (NOC,S) Evolution of the W. Gulf of Corinth December 2006 3 / 12 Introduction Gulf of Corinth Tectonics The Gulf of Corinth

22˚00' 22˚30' 23˚00' 38˚30'

Itea Nafpaktos Antikyra Trizonia Erateini Galaxidi Major active faults

−1000 0 1000 2000 Straits of m Rion Patra −200 Domvrena Aigion Eliki 10-15 mm/yr Gulf of −400 20˚ EURASIAN 25˚ 30˚ Corinth PLATE < 5 mm/yr Greece 2-4 mm/yrAkrata −800 40˚ 5-10 mm/yr Alkyonides Gulf Turkey ANATOLIAN Xylokastron−600 PLATE 2 Perachora 38˚00' Kiato

McNeill and Collier 2004 km 35˚ AFRICAN PLATE 200 km Clarke et al., 1998 Corinthos 0 10 20

Bell, McNeill, Bull, Henstock (NOC,S) Evolution of the W. Gulf of Corinth December 2006 3 / 12 Introduction Gulf of Corinth Tectonics The Gulf of Corinth

22˚00' 22˚30' 23˚00' 38˚30'

Itea Nafpaktos Antikyra Trizonia Erateini Galaxidi Major active faults

−1000 0 1000 2000 Straits of 1. Wm Rion Patra −200 Domvrena Aigion i Eliki Gulf of −400 20˚ EURASIAN 25˚ 30˚ Corinth PLATE a Greece Akrata −800 40˚ Alkyonides Gulf Turkey ANATOLIAN Xylokastron−600 PLATE Perachora 38˚00' Kiato

km 35˚ AFRICAN PLATE 200 km Corinthos 0 10 20

1 What is the offshore structure of the W. Gulf of Corinth?

2 How has this part of the rift evolved? 3 Is the W. Gulf of Corinth an asymmetric half graben?

Bell, McNeill, Bull, Henstock (NOC,S) Evolution of the W. Gulf of Corinth December 2006 3 / 12 Stratigraphy Shelf and upper slope Shelf and upper slope: Eratini sub-basin

Bell, McNeill, Bull, Henstock (NOC,S) Evolution of the W. Gulf of Corinth December 2006 4 / 12 Stratigraphy Shelf and upper slope Shelf and upper slope: Eratini sub-basin

Bell, McNeill, Bull, Henstock (NOC,S) Evolution of the W. Gulf of Corinth December 2006 4 / 12 Stratigraphy Deep central Gulf Stratigraphy of the Deep Central Gulf

Bell, McNeill, Bull, Henstock (NOC,S) Evolution of the W. Gulf of Corinth December 2006 5 / 12 Stratigraphy Deep central Gulf Stratigraphy of the Deep Central Gulf

Bell, McNeill, Bull, Henstock (NOC,S) Evolution of the W. Gulf of Corinth December 2006 5 / 12 Basin Geometry Western Gulf structure

Bell, McNeill, Bull, Henstock (NOC,S) Evolution of the W. Gulf of Corinth December 2006 6 / 12 Basin Geometry Western Gulf structure

Bell, McNeill, Bull, Henstock (NOC,S) Evolution of the W. Gulf of Corinth December 2006 6 / 12 Basin Geometry Fault Architecture and Basement Structure

22˚12' 22˚24'

38˚24' 0 −200 Trizonia Galaxidi Erateini −400

−600

−800 Bathymetry (m) 38˚18'

Aigion Eliki

38˚12' Diakopto

Akrata 22˚ 23˚

38˚ 0 5 10 38˚06'

Bell, McNeill, Bull, Henstock (NOC,S) Evolution of the W. Gulf of Corinth December 2006 7 / 12 Basin Geometry Fault Architecture and Basement Structure

22˚12' 22˚24'

38˚24' 0 500

Trizonia Galaxidi 1000 Erateini 1500

2000

2500

3000 TWTT depth 38˚18' 600 to sed.-base contact (ms) 1000 14001200

Aigion Eliki

38˚12' Diakopto

Akrata 22˚ 23˚

38˚ 0 5 10 38˚06'

Bell, McNeill, Bull, Henstock (NOC,S) Evolution of the W. Gulf of Corinth December 2006 7 / 12 Basin Evolution East Basin evolution: east

Bell, McNeill, Bull, Henstock (NOC,S) Evolution of the W. Gulf of Corinth December 2006 8 / 12 Basin Evolution East Basin evolution: east

Bell, McNeill, Bull, Henstock (NOC,S) Evolution of the W. Gulf of Corinth December 2006 8 / 12 Basin Evolution Central Basin evolution: central

Bell, McNeill, Bull, Henstock (NOC,S) Evolution of the W. Gulf of Corinth December 2006 9 / 12 Basin Evolution Central Basin evolution: central

Bell, McNeill, Bull, Henstock (NOC,S) Evolution of the W. Gulf of Corinth December 2006 9 / 12 Rift History Discussion Western Gulf of Corinth Rift History

22°10'0"E 22°20'0"E Early to Middle Pleistocene (~1.5 Ma to ~0.4 Ma) Galaxidi Eratini Lacustrine? Continental? Study area limit Faults are predicted to have initiated ~1.5 Ma 38°20'0"N Max. sed. thick. based on the estimated age of oldest sediments Block tilting Present coastline Activity on the south dipping faults in the 0.6 mm/yr 1.2 mm/yr centre of the modern basin controls structure AIG 0.8km 1.5km AigionEliki i

The footwalls of the south dipping faults re- W ELI mained largely sediment free E ELI Diakopto o

Pleistocene averaged slip rates are of the 38°10'0"N Akrata ta order 0.6 -1.2 mm/yr Kilometers 01 2 4 6 8 10 Hangingwall basement structure shows north- ward tilt Basin structure : East = Asymmetric north dipping half graben West = Asymmetric north dipping half graben

Bell, McNeill, Bull, Henstock (NOC,S) Evolution of the W. Gulf of Corinth December 2006 10 / 12 Rift History Discussion Western Gulf of Corinth Rift History

22°10'0"E 22°20'0"E

Middle Pleistocene to recent (~0.4 Ma to 0 Ma) Marine Eratini Continental Study area limit Activity on the north and south dipping Max. sed. thick. 38°20'0"N Block tilting north margin faults initiates almost simultane- 0.4km Present coastline ously ~0.5 Ma. M. ~1 mm/yr

1 - 1.5 mm/yr Increased activity on south coast faults causes 0.5km AIG block tilting to the south AIGAigion El i Eliki Slip rates on the south dipping central W ELI faults decrease to ~0.3mm/yr. E. ELI Diakopto E ELI o W. ELI 38°10'0"N Akrata Pleistocene averaged slip rates for the north Kilometers margin faults are ~1-1.5mm/yr. 01 2 4 6 8 10

Periodic marine invasion of the western Gulf occurs post ~0.4 Ma producing the sediments of unit A. Basin structure : East = Asymmetric south dipping half graben West = Asymmetric north dipping half graben

Bell, McNeill, Bull, Henstock (NOC,S) Evolution of the W. Gulf of Corinth December 2006 10 / 12 Conclusions Conclusions 1

22˚12' 22˚24'

38˚24'

Trizonia Galaxidi 1 Rifting initiated ~1.5 Ma. Erateini

38˚18' 2 Stratigraphy can be split into two distinct units separated by a regional Aigion unconformity. This unconformity is Eliki

38˚12' predicted to have an age of ~0.4 Ma. Diakopto

Akrata 22˚ 23˚

3 Activity of the south dipping central 38˚ 0 5 10 faults decreases post ~0.4 Ma and 38˚06' extension is transferred to the faults of the northern margin and southern coastline.

Bell, McNeill, Bull, Henstock (NOC,S) Evolution of the W. Gulf of Corinth December 2006 11 / 12 Conclusions Conclusions 2

1 The net structure of the basin varies from being a strong N dipping half graben in the west of the study area to being a more symmetrical graben in the east. 2 This contrasts with the structure of the eastern Gulf of Corinth and Alkyonides gulf which has been a predominantly south dipping half graben through time.

West East S N S N

3 Early rift evolution in the Western Gulf of Corinth is complex, varying in both space and time

Bell, McNeill, Bull, Henstock (NOC,S) Evolution of the W. Gulf of Corinth December 2006 12 / 12