Subduction initiation in the Neotethys:
from field evidences to numerical modelling
Alexis Plunder, Cédric Thieulot and Douwe J.J. van Hinsbergen.
Address
A. Plunder, C/ Thieulot, D. van Hinsbergen Dept. of Earth Sciences, Utrecht University
Van Unnikgebouw | Heidelberglaan 2 | 3584 CS Utrecht | contact: a.v.plunder@uu.nl
A. P and D.J.J. v. H are grateful to the ERC starting grant SINK (306810) awarded to D.J.J. v.H.
{ELEFANT} (Thieulot, 2014)
Finite element thermomecanically coupled code
Temperature profile of a ca. 110 vs. 160 My old oceanic lithosphere.
Computed as a semi-infinite half-space.
Material: olivine with a non Newtonian and temperature dependant viscosity following Karato & Wu (1993)
µ
eff= f 1
2 A
n1˙ε
(IIn1 − 1)exp Q + P V nRT
Faculty of Geosciences
{Preliminaryresults}
Present day configuration
To be tested
0 200 400 600
0 400 800 1200 1600
0 200 400 600
0 400 800 1200 1600 1800
0 200 400 600
0 400 800 1200 1600 1800
0 200 400 600
0 400 800 1200 1600 1800
0 200 400 600
0 400 800 1200 1600 1800
0 200 400 600
0 400 800 1200 1600 1800
0 200 400 600
0 400 800 1200 1600 1800
0 200 400 600
0 400 800 1200 1600 1800
0 200 400 600
0 400 800 1200 1600 1800
0 200 400 600
0 400 800 1200 1600 1800
338 677 1015
0 1354
Temperature
Fracture zone
Flow in
Flow out
=
110 My 160 My
Vx=0
Vz=0 Vx=FS
Vz=FS
Africa
Fracture zone are comon objects. Average width is about 20 km and can go up to 100 km when there are close fracture zones (Romanche fracture zone for example).
Difference in age typically varies from 10 to 50 My.
South America South
America
North America Murray FZ
Udintsev FZ
FZ Mendocino FZ
Molokai FZ
Romanche FZ
FZ FZ FZ
Eltanin FZ
Clarion FZ
Subduction initiation at transform zones is possible!!!
Possibility to form metamorphic sole Influence of shear heating
Half out flow on the other side of the domain Mesh refinement
Increased resolution
{Introduction}
Subduction initiation is an unresolved question of plate
tectonics. Few models have been proposed (either conceptual of physical; e.g. Stern 2004; Maffione et al., 2015; Leng & Gurnis
2015).
My approach
Here I chosed to test wether it is possible to initiate subduction at fracture zones. Why? Because we have evidences that the ridge was gone since ca. 110 Ma in the Neotethys (in Turkey) where I did most of my previous work.
Tav.
Inner Taurid K
e Basin Taurides
Bitlis
Africa Pontides
Black Sea
10 20 30
Tav.
Inner Taurid K
e Basin Taurides
Ln
Al Sa
Bitlis
Africa Pontides
Black Sea
Di
Ha Ba Tr
Gö
10 20 30 40
New Subduction sytem @ 92 Ma
Newly formed Ophiolite
Fracture zone in the Neotethys FZ? FZ
95 92
0 200000 400000 600000
Z Axis
0 200000 400000 600000 800000 1e+6 1.2e+6 1.4e+6 1.6e+6 1.8e+6 2e+6 2.2e+6 X Axis
0 200000 400000 600000
Z Axis
0 200000 400000 600000 800000 1e+6 1.2e+6 1.4e+6 1.6e+6 1.8e+6 2e+6 2.2e+6 X Axis
1e-18 1e-17 1e-16 1e-15 1e-14
1.000e-19 2.851e-14
strainrate II
0 200000 400000 600000
Z Axis
0 200000 400000 600000 800000 1e+6 1.2e+6 1.4e+6 1.6e+6 1.8e+6 2e+6 2.2e+6 X Axis
0 200000 400000 600000
Z Axis
0 200000 400000 600000 800000 1e+6 1.2e+6 1.4e+6 1.6e+6 1.8e+6 2e+6 2.2e+6 X Axis
340 679 1017
1.596e+00 1.356e+03
Temperature
t=0,05 My
t=0,7 My
t=1 My
0 200000 400000 600000
Z Axis
0 200000 400000 600000 800000 1e+6 1.2e+6 1.4e+6 1.6e+6 1.8e+6 2e+6 2.2e+6 X Axis
0 200000 400000 600000
Z Axis
0 200000 400000 600000 800000 1e+6 1.2e+6 1.4e+6 1.6e+6 1.8e+6 2e+6 2.2e+6 X Axis
340 679 1017
1.596e+00 1.356e+03
Temperature
0 200000 400000 600000
Z Axis
0 200000 400000 600000 800000 1e+6 1.2e+6 1.4e+6 1.6e+6 1.8e+6 2e+6 2.2e+6 X Axis
0 200000 400000 600000
Z Axis
0 200000 400000 600000 800000 1e+6 1.2e+6 1.4e+6 1.6e+6 1.8e+6 2e+6 2.2e+6 X Axis
1e-18 1e-17 1e-16 1e-15 1e-14
1.000e-19 3.199e-14
strainrate II
0 200000 400000 600000
Z Axis
0 200000 400000 600000 800000 1e+6 1.2e+6 1.4e+6 1.6e+6 1.8e+6 2e+6 2.2e+6 X Axis
0 200000 400000 600000
Z Axis
0 200000 400000 600000 800000 1e+6 1.2e+6 1.4e+6 1.6e+6 1.8e+6 2e+6 2.2e+6 X Axis
1e-18 1e-17 1e-16 1e-15 1e-14
1.000e-19 3.199e-14
strainrate II
1e-18 1e-17 1e-16 1e-15 1e-14
1.e-19
strainrate II
338 677 1015
0 1354
Temperature
0 200000 400000 600000
Z Axis
0 200000 400000 600000 800000 1e+6 1.2e+6 1.4e+6 1.6e+6 1.8e+6 2e+6 2.2e+6 X Axis
0 200000 400000 600000
Z Axis
0 200000 400000 600000 800000 1e+6 1.2e+6 1.4e+6 1.6e+6 1.8e+6 2e+6 2.2e+6 X Axis
1e-18 1e-17 1e-16 1e-15 1e-14
1.000e-19 3.199e-14
strainrate II
0 200000 400000 600000
Z Axis
0 200000 400000 600000 800000 1e+6 1.2e+6 1.4e+6 1.6e+6 1.8e+6 2e+6 2.2e+6 X Axis
0 200000 400000 600000
Z Axis
0 200000 400000 600000 800000 1e+6 1.2e+6 1.4e+6 1.6e+6 1.8e+6 2e+6 2.2e+6 X Axis
1e+20 1e+21 1e+22 1e+23 1e+24
1.014e+19 1.000e+25
mueff (nodal)
0 200000 400000 600000
Z Axis
0 200000 400000 600000 800000 1e+6 1.2e+6 1.4e+6 1.6e+6 1.8e+6 2e+6 2.2e+6 X Axis
0 200000 400000 600000
Z Axis
0 200000 400000 600000 800000 1e+6 1.2e+6 1.4e+6 1.6e+6 1.8e+6 2e+6 2.2e+6 X Axis
1e+20 1e+21 1e+22 1e+23 1e+24
4.024e+19 1.000e+25
mueff (nodal)
1e+20 1e+21 1e+22 1e+23 1e+24
1.014e+19 1.000e+25
mueff
0 200000 400000 600000
Z Axis
0 200000 400000 600000 800000 1e+6 1.2e+6 1.4e+6 1.6e+6 1.8e+6 2e+6 2.2e+6 X Axis
0 200000 400000 600000
Z Axis
0 200000 400000 600000 800000 1e+6 1.2e+6 1.4e+6 1.6e+6 1.8e+6 2e+6 2.2e+6 X Axis
1e+20 1e+21 1e+22 1e+23 1e+24
1.014e+19 1.000e+25
mueff (nodal)
0 200000 400000 600000
Z Axis
0 200000 400000 600000 800000 1e+6 1.2e+6 1.4e+6 1.6e+6 1.8e+6 2e+6 2.2e+6 X Axis
0 200000 400000 600000
Z Axis
0 200000 400000 600000 800000 1e+6 1.2e+6 1.4e+6 1.6e+6 1.8e+6 2e+6 2.2e+6 X Axis
340 679 1017
1.596e+00 1.356e+03
Temperature
0 200000 400000 600000
Z Axis
0 200000 400000 600000 800000 1e+6 1.2e+6 1.4e+6 1.6e+6 1.8e+6 2e+6 2.2e+6 X Axis
0 200000 400000 600000
Z Axis
0 200000 400000 600000 800000 1e+6 1.2e+6 1.4e+6 1.6e+6 1.8e+6 2e+6 2.2e+6 X Axis
1e-18 1e-17 1e-16 1e-15 1e-14
1.000e-19 3.199e-14
strainrate II
