Multi-disciplinary studies for understanding the Seamounts in the Levantine Basin – Eastern

Mediterranean

Dr. V. Lykousis Research Director

Institute of Oceanography-HCMR

Mud volcanoes hydrates and methane seepage in

the Levantine basin

outline -Mud volcanoes? -Significance -Gas Hydrates -Anaximandrer Mts -Florence Rise and Eratosthenes SM -Conclusions/further work

Mud volcanoes (MV) The term mud volcanoes or mud domes are used to refer to morphological formations similar to earth volcanoes created by geo-excreted liquids and gases like fluid mud, hydrocarbons (methane) and various rock clasts originated from deep sources. Highly compressed deep sediment strata is the cause of upward migration of the geofluids through raptures or major fault zones. Usually are associated with subduction zones and mega (thick) sediment sliding.

Olympi FIELD

Cita et al.,1996; Robertson et al.,1998

DeLange & Brumsack, 1998 Dahlmann & DeLange, 2003

Napoli MV

CRETE

SSW NNE

Significance of MV Mud volcanoes are often associated with petroleum deposits and the active ones are the seabed witnesses for the presence of deep hydrocarbon resources Mud volcanoes are “oasis” of symbiotic benthic communities providing the primary energy/food (carbon) source from the hydrocarbons (chemosynthesis) Mud volcanoes are associated with the creation of hydrocarbon clathrate/gas hydrate deposits.

Isorropodon perplexum 2-14 mm

Myrtea amorpha 8-20 mm

Idas modiolaeformis 2-17 mm

Typical benthic communities of mud volcanoes

Lucinoma kazani 15 -40 mm

Thyasira striata 2-9 mm

3 см

В

CH4.6H2O

Methane hydrate structure

Gas hydrates or hydrates

Sea bed

Sea water

Sub-bottom Sediments + CH4 +GH

Fluid mud+CH4 +H2O Relatively high To

CH4 free gas

Upward free gas dispersion and

Cooling

Г 1 см

1 m3 Gas hydrate=164m3 CH4 Future Energy Source

Contribution to the Global Change

Contribution to slope instabilities-hazards

CH4 Fluidized hydrates

CH4 gas Temperature

increase

Το μέλλον της θαλάσσιας ερευνας στην Ελλάδα, Ιδρυμα Ευγενίδου 14-15 Νοεμβρίου 2011

Morpho-bathymetric map of the Mediterranean

CIESM and IFREMER

Anaximander Mts

Florence rise

Eratosthenes SM

May, 2003

November, 2004

ANAXIMANDER EU Project

Gas hydrate sites (sampled) Gas hydrate sites (inferred)

ANAXIMANDER

R/V AEGAIO 2003,2004

Bathymetric/Backscatter image. High backscatter (ORANGE) probably from mud breccia with methane gas indicating MUD

VOLCANISM

Amsterdam

Kazan

Kula

Athina

Thessaloniki ~1200m

Amsterdam Mud Volcano

Central crater

Shaded relief and backscatter image. Dark blue indicates high backscatter (fluid mud with methane gas

and rock clasts from deep sources)

2 km

0

500

1000

1500

2000

2500

0 50 100 150 200CH4 [nM]

dept

h [d

bar]

03 CT 1

05 CT 1

08 CT 1

020

406080

100

120140

0 2500 5000

CH4 [µmol/l wet sed]

dept

h [c

mbs

f]

AN 05 BC5-1

AN 05 GC3

AMSTERDAM MV

Water column

Subbottom sediments

Methane plume

Methane hydrates

SEA BED

G.de Lange team, Un. of

Utrecht

GH AN05BC3 AN05GC3

2004

1 Box core

13 Gravity cores

5 MAK

4 APCA

3 Gravity cores

10 Box cores

2003 AMSTERDAM MUD VOLCANO

GH AX02GC2 AX06GC1 AX09GC1 AX10GC1 AX11GC1 AX15GC1

Sampling sites

Slow depressuarisation –collection of released methane from GH- actual methane

concentration/volume sediment (Vmeth/Vsed)

High in-situ pressure

Hydrocarbon (methane gas) potential of the Anaximander MVs

(Lykousis et al., 2009)

Rough estimations of the total volume of methane gas in the Anaximander MVs are about 6.40 km3 (6.40 109 m3 of methane gas), - if the base of GH/BSR at 200 m (Praeg et al., 2007) - and assuming uniform density of GH with burial depth

In 2005 (scale 1/2000 000)

Florence rise

Eratosthenes SM

Florence rise

Woodside et al., 2002

Anaximander Mts

TEXEL MV

Woodside et al., 2002

DSDP drilling

Activity of Texel MV? GH??

J.Mascle Fluid seepages from

backscatter images of the Eastern Mediterranean Sea

ERATOSTHENES SM

J.Mascle Fluid seepages from

backscatter images of the Eastern Mediterranean Sea

NAUTILUS Expeditions 2008?, 2011, 2012

NAUTILUS Expedition (www.nautiluslive.org)

NAUTILUS Expedition (www.nautiluslive.org)

CONCLUSIONS / FURTHER WORK

-Detailed investigations on the Florence rise MVs and methane seeps of the Eratosthenes SM (multibeam, ROV observations and sampling, seabed coring, water column sampling etc), Benthic biodiversity-benthic habitat mapping of the Eratosthenes SM

-extension of methane seepage on Eratosthenes SM? activity of MVs (methane plumes?), GH on Florence rise?, complicate geology (“columnar” limestones?) etc

Thank you