Various-scale controls of complex subduction dynamics on magmatic-hydrothermal processes in eastern Mediterranean

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Various-scale controls of complex subduction dynamics

on magmatic-hydrothermal processes in eastern

Mediterranean

Armel Menant, Laurent Jolivet, Pietro Sternai, Maxime Ducoux, Romain

Augier, Aurélien Rabillard, Taras Gerya, Laurent Guillou-Frottier

To cite this version:

Armel Menant, Laurent Jolivet, Pietro Sternai, Maxime Ducoux, Romain Augier, et al.. Various-scale controls of complex subduction dynamics on magmatic-hydrothermal processes in eastern Mediter-ranean. EGU General Assembly 2014, Apr 2014, Vienne, Austria. �hal-00933496�

(2)

Introduction

Large-scale evolution: input from kinematic reconstructions

Small-scale evolution: the Miocene geodynamics of the Aegean and western Anatolia

Combined scales: numerical modeling of subduction dynamics

Conclusion

References

Various-scale controls of complex subduction dynamics on magmatic-hydrothermal processes

in eastern Mediterranean

EGU 2014 - 5120

A. Menant

1,2,3

, L. Jolivet

1,2,3

, P. Sternai

1,2,3

, M. Ducoux

1,2,3

, R. Augier

1,2,3

, A. Rabillard

1,2,3

, T. Gerya

4 , L. Guillou-Frottier

2,1,3

1

2 Univ. d’Orléans, ISTO, UMR 7327, 45071 Orléans, France (a.menant@brgm.fr)

_{BRGM, ISTO, UMR 7327, 45060 Orléans, France}

3 _{CNRS/INSU, UMR 7327, 45071 Orléans, France}

4 _{Swiss Federal Institute of Technology (ETH), Zurich, Switzerland}

oceanic crust

dehydration of oceanic lithosphere

continental crust

asthenosphere

volcanic arc

back-arc domain

sea level

sediments

metasomatised asthenosphere

asthenospheric

upwelling

lower crustal

MASH zone

feeder dikes

mid- to upper crustal

I-type batholithic complex

oceanic lithospheric

mantle

subduction-modified

lithospheric mantle

m

_a

_nt

_l

_e cor

n

_er_fl

_o

_w

hydrothermal alteration

Au-Cu-rich epithermal deposits

Au-rich epithermal deposits

Cu-rich porphyry and skarn-related deposits

Ore deposits and related

magmatism in subduction and

post-subduction environments

are controlled by the thermal

structure and hydrous and

magmatic fluid dynamics from

the underlying mantle to the

upper crust.

In regions where the

3D subduction dynamics is complex such as in

eastern Mediterranean,

Modified from Richards, 2011

Which processes affect the distribution of mineralization

and magmatism?

Considering this evolution at different scales, can we better

constrain the dynamics of subduction in eastern Mediterranean?

Present-day latitude (°N)

100

90

80

70

60

50

40

30

20

10

0 Age (Ma)

42

38

40

36

34

44

46 increasing rate of slab

retreat (~35-30 Ma)

continental accretion

subduction of the Vardar oceanic crust

late Cretaceous Paleocene Eocene Oligocene Miocene Plio.-Q.

Pelagonian

continent

Pindos oceanic

crust

Rhodope MCCs

Gavrovo-Tripolitza

continent

Ionian oceanic crust

B

alk

an

be

lt

Cyclades and

Menderes MCCs

- Calc-alkaline magmatism

- Porphyry Cu deposits

- K-rich magmatism

- Pb-Zn and Au-rich

epithermal deposits

80 Ma

B

_a

lkan

_s

Var

_da

r

_o

_c

e

_a

n

Pe

_l

ago

nia

_n

Pi

_n

_d

o

_s

o

_ce

a

_n

I

zm

i

r

-An

k

a

r

a

ocea

n

K

_i

_r

_ş

_eh

_ir

Ta

_u

_ri

d

_e

_s

Black

Sea

In

_n

_e

_r

-Ta

_{uride oc}

e

_an

Lycian-Tauride

ophiolites

P

ont

i

de

s

55 Ma

B

_al

_kans

P

_i

_nd

os

o

_c

_e

a

_n

Taurides

Lycian-Tauride

ophiolites

Tavsanlı-Afyon

G

_a

v

_r

_o

vo-T

_ri

poli

_t

_za

Ion

_ian

Rhodopes

K

_i

_r

_ş

_e

_h

_i

r

80 Ma

B

_a

lkan

_s

Var

_da

r

_o

_c

e

_a

n

Pe

_l

ago

nia

_n

Pi

_n

_d

o

_s

o

_ce

a

_n

I

zm

i

r

-An

k

a

r

a

ocea

n

K

_i

_r

_ş

_eh

_ir

Ta

_u

_ri

d

_e

_s

P

ont

i

de

s

Black

Sea

In

_n

_e

_r

-Ta

_{uride oc}

e

_an

Lycian-Tauride

ophiolites

55 Ma

B

_alk

_a

ns

P

indos

_oc

ean

Taurides

Lycian-Tauride

ophiolites

Tavsanlı-Afyon

Ga

_v

rov

o-T

_ri

po

_lit

_z

a

Rhodopes

Ki

r

ş

_ehir

Magmatism

Ore deposits

Tectonic structures

active major thrust fault

active major low-angle normal fault

active major high-angle normal fault

inactive major fault

active major strike-slip fault

major oceanic suture

shoshonitic v./p.

volcanism/plutonism (v./p.)

alkaline v./p.

high-K calc-alkaline to shoshonitic v./p.

high-K calc-alkaline v./p.

medium- to high-K calc-alkaline v./p.

medium-K calc-alkaline v./p.

Magmatism

_{Ore deposits}

_{metal content}

deposit type

Cu

porphyry

skarn

high-sulphidation epithermal

low-sulphidation epithermal

fault-related

volcano-sedimentary

Au

Pb-Zn

Fe

obducted oceanic crust

oceanic crust

continental crust

Petrological affinity

Metamorphic Core Complex (MCC)

buried/exhumed high pressure MCC

buried/exhumed high temperature MCC

1. Late Cretaceous - early Paleocene

- Calc-alkaline magmatism

- Cu-rich deposits

2. Late Paleocene - Eocene

- Barren period

3. Oligocene - Neogene

- K-rich magmatism

-

Pb-Zn- and Au-rich

deposits

Latitude versus age diagram from the

magmatic and metallogenic events

3 main periods in eastern

Mediterranean with a general

southward migration of the

magmatic-hydrothermal systems

30 Ma

Ta

_u

_ri

_d

es

Menderes

Gav

rovo

_-

_T

ri

_po

l

_itza

Mes

_o

_g

e

_a

_n

ocean

Rhodopes

Cyclades

30 Ma

Ta

_u

rides

Menderes

Gav

_r

_o

v

_o

-Tr

_ip

olit

_za

Mes

_og

e

_a

_n

ocean

Rhodopes

Cyclades

15 Ma

Meso

gean oc

_ean

Menderes

Arabia

Rhodopes

Cyclades

15 Ma

Meso

gean oc

_ean

Menderes

Arabia

Rhodopes

Cyclades

0 Ma

fixed Eurasia

N

300 km

0 Ma

Balkan belt

Rhodopes

Rhodope MCC

W-Anatolia

Cyclades

100 km

slow slab retreat

fast slab retreat

accretion of the

Pelagonian domain

inception of the

Rhodope MCC

subduction-modified

lithospheric mantle

Cu(-Au)

Au

Cu

Pb-Zn

Cu(-Au)

Au

_Au

Au

Pb-Zn

Cu

N

S

N

S

N

S

80 Ma

55 Ma

15 Ma

hot asthenospheric

flow

hot

asthenospheric

flow

18.8 Myr

sediments

back-arc extension

20.8 Myr

lateral extrusion

partially

molten mantle

horizontal slab tear

vertical slab tear

continental collision

Field evidences

Mykonos island

- Syn-extensional granodiorite below the NCDS

- Au-bearing silica breccia and base metal-barite veins

Using a simple large-scale model of subduction, can we

reproduce these geological observations and relate them

to the subduction dynamics and associated mantle flow?

Since 35-30 Ma, fast slab retreat resulted in the opening of the Aegean back-arc domain.

However, 15 Ma ago, a major change occurred in the dynamics of this back-arc opening.

- Syn-extensional granodiorite below the WCDS

- Fe-rich high temperature and medium temperature skarns

Serifos island

Block rotations

[van Hinsbergen et al., 2005]

Appearance and westward

migration of alkaline volcanism

[Dilek & Altunkaynak, 2009]

Westward migration of

plutonism from the Menderes to

Cyclades with an

increase of the

mantle component

[Altherr & Siebel, 2002]

In the Cyclades, the

activity of large-scale detachment systems such as the North

Cycladic Detachment System (NCDS) and the West Cycladic Detachment System (WCDS)

is

contemporaneous with the emplacement of magmatic intrusions and ore deposits

NE

WSW

ENE

Miocene sediments

Mykonos detachment (NCDS)

Cycladic blueschists unit

brecciated skarn

ilvaïte

hedenbergite

Megálo Livádi detachment (WCDS)

Cycladic continental basement

deformed granodiorite

SW

50 m

0 1.5 cm/yr

0

656 z km

680 2000

x km

y

km

overriding continental

plate

_(Eurasia)

continent

oceanic plate

(Arabia)

lithospheric mantle

Asthenosphere

upper

crust

lower crust

weak zone

x = 2000 km

300 °C

600 °C 900 °C

overriding continental plate

continent

1200 °C

x = 0 km

y = 0 km

y = 680 km

1e+19

1e+20

1e+21

log viscosity (Pa.s)

1e+22

1e+23

3D thermo-mechanical numerical modeling with complex

rheologies, integrating fluid/melt transport, partial melting

and melt extraction mechanisms [Gerya & Yuen, 2003]

brecciated Fe-skarn

100 m

1000 m

Au-bearing silica breccia

silicified clast

Fe-hydroxide matrix

barite

18.2 Myr

19.6 Myr

20.8 Myr

25 km-depth horizontal cross-sections (base of stretched crust)

hydrated-molten crust

(orange)

hydrated-molten

mantle

(pink)

asthenosphere

(white)

sediments

(light yellow)

molten sediments

(yellow)

neoformed

crust

(red)

Lateral migration of magmatism and asthenospheric

upwelling related to toroidal flow

In back-arc region, increase of mantle-derived material

relative to crustal-derived material

15 Ma

fast slab retreat

9 Ma

~30°

~20°

NCDS

WCDS

200 km

southward migration of magmatic-hydrothermal systems is

observed from the late Cretaceous to nowadays

In eastern Mediterranean region, a

During the Miocene, a secondary westward migration of the

_{magmatic-hydrothermal activity is observed from the Menderes}

massif to the Cyclades

Barren periods are associated to dominant compressional or

transpressional tectonics within the upper plate (e.g. continental

accretion)

Cu-rich periods are related to stagnant magmatic arc resulting

from the

_{dehydration of the subducted oceanic crust and the}

partial melting of the mantle wedge

Au-rich periods are related to fast slab retreat and associated

mantle flow inducing the partial melting of the lithospheric mantle

or the base of the crust where Au was previously stored

Possible consequence of a slab tearing event below western Anatolia and

related hot asthenospheric flow

Dilek Y. & S. Altunkaynak (2009), Geochemical and temporal evolution of Cenozoic magmatism in western Turkey: mantle response to collision,

slab break-off, and lithospheric tearing in an orogenic belt, Spe. Pub. - Geol. Soc. London, 311, 213-233.

Gerya T. V. & D. A. Yuen (2003), Characteristics-based marker-in-cell method with conservative finite-differences schemes for modeling

geological flows with strongly variable transport properties, Phys. Earth Planet. Int., 140, 293-318.

Richards J. P. (2011), Magmatic to hydrothermal metal fluxes in convergent and collided margins, Ore Geol. Rev., 40, 1-26.

van Hinsbergen D. J. J., et al. (2005), Revision of the timing, magnitude and distribution of Neogene rotations in the western Aegean region,

Tectonophysics, 396, 1-34.

Altherr R. & W. Siebel (2002), I-type plutonism in a continental back-arc setting: Miocene granitoids

and monzonites from the central Aegean Sea, Greece, Contrib. Mineral Petrol., 143, 397-415.

A

na

to

l

ia

Bl

ac

k S

ea

M

ez

og

ea

n

A

_f

_r

_i

_c

_a

14-13 Ma

(Mykonos)

15-14 Ma

(Tinos)

9-8 Ma

(Lavrion)

21-20 Ma

(Egrigöz)

16-15 Ma

_(Salhili)

Peloponnese

Crete

12-9 Ma

(Serifos)

13-12 Ma

(Naxos)

Metamorphic Core Complex (MCC)

Magmatism

buried/exhumed high pressure MCC

buried/exhumed high temperature MCC

Miocene intrusion

European Geosciences Union General Assembly 2014, Vienna, Austria, 28 april - 02 may 2014