emergence of silicic continents as the lower crust peels ...major phase of felsification of upper...
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1
Supplementary Information
Emergence of silicic continents as the lower crust peels
off on a hot plate-tectonic Earth
Priyadarshi Chowdhury1*, Taras V. Gerya2, Sumit Chakraborty1
1Ruhr-Universität Bochum, Institut für Geologie, Mineralogie & Geophysik,
Univertsitätsstrasse 150, 44801 Bochum, Germany.
2Swiss Federal Institute of Technology Zurich, Department of Earth Sciences,
Sonneggstrasse 5, 8092 Zurich, Switzerland.
Correspondence to: Priyadarshi Chowdhury ([email protected])
Contents:
Supplementary text for ϕ, ϕTp, ξ
Supplementary text for Figure 3c and 4b
Supplementary Figures 1 to 9
Supplementary Table 1
© 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.
SUPPLEMENTARY INFORMATIONDOI: 10.1038/NGEO3010
NATURE GEOSCIENCE | www.nature.com/naturegeoscience 1
2
Supplementary text for ϕ, ϕTp, ξ
Parameter ϕ - The recycled volumes for each model are represented by a dimensionless
parameter ϕ (Supplementary Table 1) that is defined as-
𝜙 = {Recycled Volume in the model
Initial continental volume in the model 𝑥 1000}
The total initial volume of continental crust for various combinations of continental
thickness and oceanic plate length are-
Continental
thickness (km)
Oceanic Plate
length (km)
Initial continental
vol. (km3/km)
40 400 141573
40 600 131574
40 1000 117588
35 600 116951
No recycling is observed in models with 300 km long oceanic plate (Supplementary
Table 1) and therefore these models are not used for determining recycling volume/flux.
The definition of parameter ϕ makes the recycled volume independent of the dimension
of the continental plates, which is particularly useful for peeling-off caused recycling.
Model-selection for ϕTp and ξ- ϕTp denotes the average recycling magnitude at each
investigated mantle Tp and is calculated using ϕ’s of the selected representative models
corresponding to each studied mantle Tp. Same model-grouping is used to calculate the
characteristic recycling flux- ξ - at each studied mantle Tp as shown in Figure 4b. The
selected models at each investigated mantle Tp and the underlying rationale are given
below-
3
1275-1375 °C – All crustal-melting enabled models with strong LCC.
1425 °C - Model pprb. We have only a single experiment for this mantle Tp.
1475 °C - Models eprg and eprm.
1525 °C - Models eprd, eprh, eprj and eprl.
See Supplementary Table 1 for the model details. For calculating the ϕTp of
present-day mantle temperature conditions (Tp = 1275-1375 °C), we have only
considered the models in which crustal-melting is enabled (Supplementary Table 1).
Although our experiments show negligible effect of crustal-melting on the recycled
volume, the crustal-melting numerical experiments depict more realistic geodynamic
scenarios. If we include the crustal-melting absent models in the calculation, we obtain
a ϕTp = 5.2 ± 2.9 (n=31, Supplementary Table 1). This value is not significantly different
from our preferred ϕTp = 5.9 ± 3.2 (n=19, Supplementary Table 1) obtained from
crustal-melting enabled models. Furthermore, our models showing peeling-off
recycling due to the presence of weak LCC under present-day mantle Tp yield an
average ϕ = 77.2 ± 7.2 (n=7, Supplementary Table 1). Including this average ϕ for
peeling-off recycling in the calculation of ϕTp for present-day mantle temperature
conditions, requires the knowledge of the relative contribution of break-off recycling :
peeling-off recycling towards the net recycled magnitude. If we assume that
contribution from break-off recycling : peeling-off recycling is 95% : 5%, we obtain a
ϕTp = (0.95 x 5.9) + (0.05 x 77.2) = 9.4 and if the ratio is 90%:10%, then ϕTp = 12.99.
Therefore, our preferred ϕTp = 5.9 ± 3.2 represents the most conservative estimate of
recycling magnitude at present-day collisional orogens. Since the ratio (break-off
recycling : peeling-off recycling) is largely unknown, its introduction using an
arbitrarily chosen value would add unnecessary uncertainties to the ϕTp calculation.
Instead, we prefer to exclude the contribution of peeling-off recycling from ϕTp and
4
work with the limiting conservative estimate, recognizing that there is some
contribution of peeling-off to the overall recycling magnitude. Most significantly, all
of these values are far less than the ϕTp obtained for hotter mantle conditions (~177 and
306 at 1475 °C and 1525 °C Tp respectively; see text). Therefore, any choice of ϕTp for
modern mantle conditions from the range described above would have an insignificant
effect on the major conclusion of our study that recycling declined with the cooling of
the mantle.
For 1475 °C and 1525 °C, we constrained the ϕ only from LCC-eclogitization
models only because they correspond to the ages when a thick (≥ 20 km) completely
mafic (basaltic/gabbroic) LCC might have existed9-12. Recent studies show that the
major phase of felsification of upper continental crust was achieved by the end of
Archean11 while that of bulk continental crust continued till ~2.0-1.5 Ga (ref. 10). This
indicates that an extremely thick (≥20 km) totally mafic lower continental crust is viable
over the time-period when mantle Tp was ≥1475 °C.
Supplementary text for Figure 3c and 4b
In Fig. 3c, the exponential curve fitting is done in MATLAB using the function
‘fit’-(https://www.mathworks.com/examples/curvefitting/mw/curvefit-ex72685292-
fit-exponential-models-using-the-fit-function#1). The calculated r2= 0.94 suggests a
very good fit to the data. The interpolation of ξ values between the experimental data
points (Fig. 4b) is done using a shape preserving interpolation scheme called Piecewise
Cubic Hermite Interpolating Polynomial (PCHIP) in MATLAB-
(https://de.mathworks.com/help/matlab/ref/pchip.html ). This interpolation scheme
5
ensures that the shape of the interpolant is as exact as possible between the experimental
data points. Further, assuming that the ξ-value at ~2.1 Ga to be representative of
recycling flux during the entire late Archean since the onset of global plate-tectonics at
ca. 3 Ga, we have extrapolated the ξ-curve till 3 Ga.
Air / Water
Sediments
Felsic continental crust (FCC)
Mafic continental crust (MCC)
Basalt
Gabbro
Lithospheric Mantle Asthenosphere
Hydrated / weak-zone mantle
Molten Sediments
Molten FCC
Molten MCC
Molten Basalt
Molten Gabbro
1,4
00 k
m
4,000 kma
40 km
8 km
100500900
1,300
1,500
1,700
-5 -1 -5 -1For all lithologies - α = 3 x 10 K , β = 1 x 10 MPa , C =1 MPa
54Parameters for the Flow Laws
Materialρ0
3(kg/m )
64 k(0.00004.P (MPa){ x e }
(W/m/K at T )K
53Hr
3(µW/m )
53HL
(kJ/kg)
65,66Tsolidus
(K, at P Mpa)
65,66Tliquidus
(K, at P Mpa) 54Flow Law
Sediments
Felsic continental
crust (Upper)
Mafic continental
crust (Lower)
Basalt
Gabbro
Lithopshere -
asthenosphere
dry mantle
Hydrated / Weak-
zone wet mantle
3300 (solid)
3200 (solid)
2600 (solid)
2400 (molten)
2700 (solid)
2400 (molten)
2800 (solid)
2400 (molten)
3000 (solid)
2900 (molten)
3000 (solid)
2900 (molten)
0.64+807/(T+77)
0.64+807/(T+77)
0.64+807/(T+77)
1.18+474/(T+77)
1.18+474/(T+77)
0.73+1293/(T+77)
0.73+1293/(T+77)
1.50
1.00
0.25
0.25
0.25
0.022
0.022
300
300
380
380
380
-
-
889 + 17900/(P+54) 2+ 20200/(P+54) at
P<1200 MPa;
831 + 0.06P at
P >1200 MPa
973 - 70400/(P+354) 2+ 77800000/(P+354)
at P<1600 Mpa;
935 + 0.0035P + 20.0000062P at
P >1600 MPa
-
-
{{
1262 + 0.009P
1423 + 0.105P
-
-
Wet Quartzite
V = 8 J/mol/MPa , ω = 0.15a eff
Wet Quartzite
V = 12 J/mol/MPa , ω = 0.15a eff
Wet Quartzite/Plagioclase An75
V = 8 J/mol/MPa , ω = 0.15a eff
Wet Quartzite
V = 8 J/mol/MPa , ω = 0.0a eff
Plagioclase An75
V = 8 J/mol/MPa , ω = 0.6a eff
Dry Olivine
V = 8 J/mol/MPa , ω = 0.6a eff
Wet Olivine
V = 8 J/mol/MPa , ω = 0.6a eff
ρ - Standard density; k -Thermal conductivity; H -Radioactive heat production; H -Latent heat production; ω - effective internal friction coefficient; C - Cohesion; A -Material 0 r L eff D
constant; n -Stress exponent; E -Activation energy; V -Activation volume; α -Thermal expansion coefficient; β - Isothermal compressibility. Physical properties are taken from refs. a a
53-54 and 64-66 (METHODS) as indicated.
17 22Wet Quartzite - A = 1.97 x 10 Pa.s, n = 2.3, E - 154000 J/mol Plagioclase An - A = 4.80 x 10 Pa.s, n = 3.2, E - 238000 J/mol D a 75 D a
16 20Dry Olivine - A = 3.98 x 10 Pa.s, n = 3.5, E - 532000 J/mol Wet Olivine - A = 5.01 x 10 Pa.s, n = 4.0, E - 470000 J/molD a D a
b Physical properties of lithologies used in the 2D numerical experiments
Supplementary Figure 1. Numerical model architecture. See Methods for details. a, Compositional morphology of the
full model domain. Enlarged blue box shows the geometry of the continent-ocean passive margin and the weak-layer
prescribed for subduction initiation. Pink box shows the oceanic crust morphology. All mechanical boundaries satisfy free-
slip boundary condition. Dark blue lines are isotherms with numbers indicating temperature in °C. Colour code for different
materials is shown. b, Table showing the physical properties of lithologies used in 2D numerical experiments.
6
11.82 Myr 14.03 Myr
13.37 Myr 28.75 Myr
8.71 Myr 29.40 Myr
20.13 Myr 21.60 Myr
1,900 2,300 2,700 (km)
1,900 2,300 2,700 (km)
40
0 k
mOceanic-plate Cooling Age
Thinner continental crust
Subduction Velocity
Oceanic-plate Length
slab-break-off within oceanic plate
90
km
75 km
100
500
900
1,300
a
c
e
g
b
d
f
h
Supplementary Figure 2. Parametric study of break-off recycling under present-day mantle T . cf. with the reference p
model in Fig. 1. a-b, 40-Myr (pcaa) and 100-Myr (pckk) old oceanic plate. c-d, Thinner (35 km) continents with 40-Myr
(rcab) and 80-Myr (rcfb) old oceanic plate. e-f, 7 cm/yr (pcdd) and 2 cm/yr (dcaa) convergence rate. g-h, 300-km (pccc) &
1000-km (pcqq) long oceanic plate. Blue boxes (75 km x 90 km) enlarge the recycled volumes for visual comparison. Dark
blue lines are isotherms. Dotted red lines indicate the depth of no-return. See Supplementary Table 1 for model details.
7
a
b
c
d
e
f
11.54 Myr 76.09 Myr
36.11 Myr 109.96 Myr
113.32 Myr66.17 Myr
14.47 Myr
12.94 Myr
27.23 Myr
27.61 Myr
14.57 Myr
126.61 Myr
1,500 km5
00
km
Slabbreak-off
Slabbreak-off
Slab break-off
No peeling-off
Drip-off
Drip-off
Very limited peeling-off; orogenic arrest
Extensive double-sided peeling-off
No peeling-off
No peeling-off
Stronger peeling-off
100500
900
1,300
1,500
100500
9001,300
1,500
100500
9001,300
1,500
100500
9001,300
1,500
100500
9001,300
1,500
1,700
100500
9001,300
1,500
1,700
1275 °C Mantle Tp
1325 °C Mantle Tp
1375 °C Mantle Tp
1425 °C Mantle Tp
1475 °C Mantle Tp
1525 °C Mantle Tp
Supplementary Figure 3. Influence of mantle T on the recycling dynamics . a, b, and c, Models with 1275 °C (pcff), p
1325 °C (impa) and 1375 °C (ppra) mantle T respectively, all showing only break-off recycling. d, e, and f, Models with p
increasingly higher mantle T of 1425°C (pprb), 1475 °C (pprc) and 1525°C (pprd) respectively, showing increasing degree p
of peeling-off. Compare the temporal and spatial extent of peeling-off. Dark blue lines are isotherms with numbers
indicating temperature in °C. Dotted red lines indicate the depth of no-return. See Supplementary Table 1 for model
details.
8
38.75 Myr
2.02 Myr
33.68 Myr
1.92 Myr
29.78 Myr
65.38 Myr
5.95 Myr
6.30 Myr
43.25 Myr
1,000 2,5001,500 2,000 1,000 2,5001,500 2,000
1,000 2,5001,500 2,000
1,000 2,5001,500 2,000
50
0 k
m5
00
km
1,000 3,0002,000
50
0 k
m (km) (km)
(km)
(km)
(km)
75
0 k
m
10 Myr oceanic plate, 1475 °C Mantle T , strong LCC (An )p 75
20 Myr oceanic plate, 1475 °C Mantle T , strong LCC (An ) p 75
20 Myr oceanic plate, 1525 °C Mantle T , strong LCC (An ) p 75
1000 km - 80 Myr oceanic plate, 1525 °C Mantle T , strong LCC (An ) p 75
10 Myr oceanic plate, 1475 °C Mantle T , weak LCC (WQ)pa
c
d
b
e
410 km
660 km
410 km
660 km
410 km
660 km
100500
9001,300
1,500
1,700
100500
9001,300
1,500
1,700
100500
9001,300
1,500
1,700
100500
9001,300
1,500
1,700
100 500900 1,300
1,500
1,700
Supplementary Figure 4. Recycling after shallow slab break-offs under hotter mantle conditions. Models, either with
≤ 20-Myr-old oceanic plate and strong LCC (a, c, and d, models ppre, pprg and pprh respectively) or with 1000-km-long
oceanic plate (e, model ppri) show no peeling-off after shallow break-off. Only weak LCC model with 10-Myr-old oceanic
plate (b, model wpre) shows peeling-off after shallow break-off. Dark blue lines are isotherms with numbers indicating
temperature in °C. Dotted red lines indicate the depth of no-return. See Supplementary Table 1 for model details.
9
7.19 Myr
11.17 Myr
20.94 Myr
48.35 Myr
7.51 Myr
40.86 Myr
50.38 Myr
73.98 Myr
1,000 2,5001,500 2,000 (km)
50
0 k
m
Slabbreak-off
Onset of Peeling-off
Onset of Peeling-off
Slab break-off
c Crustal melting (reworking) scenarios
1,000 2,5001,500 2,000 (km)
a 80-Myr-old oceanic plate b 20-Myr-old oceanic plate
drip-off
Crustal meltingand
relamination
(deeper) LCC and (shallower) UCC, sediments melting
mafic crust melting
new crust
1650 km 1950 km
200 k
m
200 k
m
1500 km 1900 km
00
2000 km1600 km
200 k
m0
500900
1,3001,500
1,700
100500
9001,300
1,500
1,700
100
viscousnecking
recycledLCC
9001200
9001200
9001200
Supplementary Figure 5. Influence of LCC eclogitization on peeling-off recycling under hotter mantle conditions.
Evolution of models with 80-Myr-old (a, eprd) and 20-Myr-old (b, eprh) oceanic plates at 1525 °C mantle T ; primarily p
varying in the slab break-off depth. Crustal melting facilitates the peeling-off initiation. Dark blue lines are isotherms with
numbers indicating temperature in °C. Dotted red lines indicate the depth of no-return. c, Enlarged figures show massive
melting of pre-existing crust and sediments leading to crustal growth. Note that LCC melts at greater depths while UCC and
sediments preferentially, melt at shallower depths. Margin-color of the figures corresponds to the color of the boxes within
panel (a) and (b). See Supplementary Table 1 for model details.
10
1,000 1,500 2,000 2,500 (km)
1,000 1,500 2,000 2,500 (km)
50
0 k
m
log η Map (Pa.s)10
Slab break-off
whole plate subductionand slab break-offs
Peeling-off Front
Slab break-off
Peeling-off
Slab break-off
3Density Map (kg.m )
a Higher radioactive heat generation (H ) ; felsic UCC ; 1525 °C Mantle Tr p
b Higher H ; Mafic and strong UCC ; 1525 °C Mantle Tr p c Higher H ; Mafic and weak UCC ; 1525 °C Mantle Tr p
UCC-LCCboundary
MOHOUCC-LCCboundary
MOHO
6.67 Myr
7.16 Myr
20.33 Myr
20.33 Myr
20.33 Myr 22.77 Myr
22.77 Myr
22.77 Myr
7.76 Myr
26.39 Myr
100500
9001,300
1,500
100500
9001,300
1,500
1,700
1,700
19 20 21 22 23 24 25
100500
9001,300
1,500
1,700
2.4 2.8 3.2 3.6 4.0 4.22.6 3.0 3.4 3.8
3x 10
Supplementary Figure 6. Influence of higher radioactive heat generation (H ) and mafic UCC on recycling under r
hotter mantle conditions. a, model eprl with 2.25x and 1.5x higher crustal- and mantle- H respectively, at 1525 °C mantle r
T . Slab break-off depth decreases due to higher H (cf. with Supplementary Fig. 5a). b-c, Models amcb and amce with p r
stronger and weaker mafic dominated UCC, respectively at 1525 °C mantle T . Crustal H is 2.25x higher while mantle H is p r r
1.5x higher. Density and viscosity maps for the last compositional panel are shown. Arrows indicate the velocity field. Dark
blue lines are isotherms with numbers indicating temperature in °C. Dotted red lines indicate the depth of no-return. See
Supplementary Table 1 for model details.
11
a
b
c
d
f
g
h
i
e j
8.12 Myr
11.11 Myr
16.54 Myr
23.81 Myr
21.93 Myr
24.43 Myr
25.66 Myr
31.05 Myr
Compositional Map
1,000 1,500 2,000 2,500 (km)
1,000 1,500 2,000 2,500 (km)
1475 °C Mantle Tp1275 °C Mantle Tp
50
0 k
m
log η Map (Pa.s)10
Crustal decoupling and
uprise
Mantle inflow
Coherent andcontinous Peeling-off
LCC
LCC melting
LCC Peeling-off
Development of Peeling-off Front
Decoupling within LCC
Slab break-off
Break-off recycling
Crustal melting
19 20 21 22 23 24 25
31.05 Myr 23.81 Myr
100500900
1,300
1,500
100500
9001,300
1,500
1,700
Supplementary Figure 7. Recycling involving weak LCC at present-day and hotter mantle conditions. Evolution at
1275°C mantle T (wdhh) shows decoupling of subducted continental crust from SCLM (a), followed by slab roll-back (b). p
Mantle inflow along the subduction channel (c) triggers the SCLM+LCC peeling-off (d). No slab break-off occurs. Evolution
at 1475 °C mantle T (wprc) shows shallow slab break-off (f) and crustal melting (g) resulting in the peeling-off (h-i). Inset p
(in panel g) shows melting induced indentation within the LCC. e-f, show viscosity maps for panels (d) and (i), respectively.
Dark blue lines are isotherms with numbers indicating temperature in °C. Dotted red lines indicate the depth of no-return.
See Supplementary Table 1 for model details.
12
j
0
0.4
0.8
1.2
1.6
10%
30%
50%
70%
chosenaverage
a b c d
e
i
k
f g h
33
Recy
cled V
olu
me (
x10
km
/km
)
33
Recy
cled V
olu
me (
x10
km
/km
)
pcaapcbb
pcddpcff pcjj
600
400
600
400
600
400
600
400
600
400
600
1000
1000
40
60
80
40
60
100
80
40
80
40
80
40
60
80
40
60
80 2 5 7 2 5 72 5 7 5
10 5
10 5
10
0
0.5
1.0
1.5
0
5
10
15
40
80
100
80
100
80
100 5 7
10 5 7
10
80
20
eprd
eprl
0
15
30
45
Mantle T
(°C
)p
Recyclin
g fl
ux ξ
-1
(100 M
yr
)
Age (Ga)
1,600
1,500
1,400
1,300
0.0
0.1
0.2
0.3
0.4
0.5
0.5 1 1.5 20 2.5 3 3.5 4
present-day range
0.00
0.02
0.04
0.06
0 200 400 600
Age (Ga)
0.5 1 1.5 20 2.5 3 3.5 4
0
5
10
15
20
25
30
35
Cum
mula
tive r
ecycle
d
3volu
me (
bill
ion k
m)
10%
30%
50%
70%chosenaverage
ξavgξmodel
OPL - Oceanic plate length (km)OPA - Oceanic plate cooling-age (Myr)NSV - Net subduction velocity (cm/yr)H - Radioactive heat generation.r
Recycle
d v
olu
me
3dis
trib
ution (
bill
ion k
m)
dca
a*
pca
a*
pcd
d*
dca
ap
caa
pcd
d
dcb
b*
pcf
f*p
chh
*
rca
arc
ab
rcjj
rcjb
rcfb
rcff
pca
a*
pcj
j*p
cff*
pck
k
dca
a*
dcb
b*
pca
ap
cjj
pcf
f
pcp
pp
cqq
rca
arc
jbrc
ff
rca
brc
jjrc
fb
pca
ap
cbb
pcd
d*
pcf
f*
pch
h*
pcg
g*
pce
e*
pci
i*
pca
a*
pcb
b*
pcf
fp
cqq
pcp
p
wdhh
wdee
wdaa
wdgg
wdff
wdbb
wdaa#
wdaa
wdbb
wdee
wdff
wdhh
wdgg
eprh
eprd
2.2
5x
hig
he
r cr
ust
al H
r
Norm
al cr
ust
al H
r
Present M-T ; p
Melting vs Non-meltingPresent M-T ; OPL (km)p Present M-T ; OPA (Myr)p Present M-T ; NSV (cm/yr)p
Present M-T ; p
OPA (Myr)Present M-T ; p
NSV (cm/yr)Hotter M-T ; p
OPA (Myr)Hotter M-T ; p
Hr
Strong LCC
Strong LCC with LCC-eclogitization
Weak LCC
Strong LCC and no crustal melting
Johnson et al. (ref. 16)
Herzberg et al. (ref. 17)
Mantle T investigated p
in this study
Mantle T vs. Earth’s age, p
redrawn after-
Supplementary Figure 8. Plots of the variations in recycling magnitude (a-h), evolution of recycling flux (i) and net
recycled volumes (j-k) with the age of Earth. Histograms for strong LCC models showing negligible effect of crustal
melting on break-off recycling (a) but generally increasing recycling with increasing oceanic plate length (b), oceanic plate
cooling age (c) and subduction velocity (d). Weak LCC models show that oceanic plate age increases the recycled volume
(e), whereas subduction velocity has no correlation (f). Models with LCC eclogitization under hotter mantle conditions show
no significant change in recycling magnitude with increasing oceanic plate cooling age (g) and radioactive heat generation
(h). See Supplementary Table 1 for model details. i, The recycling flux ξ is linked with the Earth's age through the existing
mantle T - Earth's age relations [redrawn after the permission from Elsevier for Herzberg et. al. (ref. 17; p doi:10.1016/j.epsl.
2010.01.022 and Macmillan Publishers Ltd: Nature Geoscience for Johnson et al. (ref. 16; doi:10.1038/ngeo2019)]. Green
13
14
and orange dots (and lines) show ξ-calculation using two different orogenic durations (see text and Fig. 4). Inset shows the
enlarged ξ-evolution from 200 Ma till present-day. j-k, Plot showing the distribution of recycled volume and the evolution of
cumulative recycled volume with the age of Earth for different orogenic continental volume %, respectively.
1,500 km
50
0 k
m
a
b
c
d
e
f
g
12
75
°C
Ma
ntle
Tp
13
25
°C
Ma
ntle
Tp
1375 °
C M
an
tle T
p1425 °
C M
antle
Tp
1475 °
C M
antle
Tp
1525 °
C M
antle
Tp
1525 °
C M
antle
Tp
LC
C E
clogiti
zatio
n
log η (Pa.s)10
2520 21 2219 23 24
14.27 Myr
12.94 Myr
11.54 Myr
36.11 Myr
27.23 Myr
112.58 Myr
48.35 Myr
Slab break-off
Slab break-off
Limited peeling-off
Stronger peeling-off
Extensive double-sidedpeeling-off
Extensive peeling-off
Slab break-off
Supplementary Figure 9. Viscosity maps
showing the evolving orogenic-recycling
dynamics with mantle T for strong LCC. p
a, model pcff with 1275 °C mantle T . b, model p
impa with 1325 °C mantle T . c, model ppra with p
1375 °C mantle T . d, model pprb with 1425 °C p
mantle T . e, model pprc with 1475 °C mantle T . p p
f, model pprd with 1525 °C mantle T . g, LCC p
eclogitization enabled model eprd with 1525 °C
mantle T . Arrows indicate the velocity field. p
Corresponding compositional maps are shown
in Supplementary Fig. 3. See Supplementary
Table 1 for model details.
15
Present mantle Tp; Strong LCC (An75)
pcaa* 1275 40 40 600 5 Slab break-off (SB) recycling (CR) 633 4.81 57/43 100/00 6 11.9 -
pcbb* 1275 40 40 400 5 SB led CR 333 2.35 38/62 100/00 0 15.0 -
pccc* 1275 40 40 300 5 SB within oceanic plate; No CR 0 0.00 0 0 0 - -
pcdd* 1275 40 40 600 7 SB led CR 813 6.18 64/36 100/00 0 8.6 -
pcee* 1275 40 40 400 7 SB led CR 333 2.35 39/61 100/00 0 13.6 -
pcff* 1275 40 80 600 5 SB led CR 899 6.83 54/46 100/00 0 14.2 -
pcgg* 1275 40 80 400 5 SB led CR 296 2.09 16/84 100/00 0 25.9 -
pchh* 1275 40 80 600 7 SB led CR 879 6.68 55/45 100/00 0 10.3 -
pcii* 1275 40 80 400 7 SB led CR 443 3.13 17/83 100/00 0 20.2 -
pcjj* 1275 40 60 600 5 SB led CR 729 5.54 57/43 100/00 0 13.1 -
dcaa* 1275 40 40 600 2 SB led CR 568 4.32 55/45 100/00 36 28.6 -
dcbb* 1275 40 80 600 2 SB led CR 778 5.91 49/51 100/00 0 42.2 -
pcaa 1275 40 40 600 5 SB led CR 635 4.83 52/48 100/00 0 11.5 yes
pcbb 1275 40 40 400 5 SB led CR 348 2.46 39/61 100/00 0 15.6 yes
pcdd 1275 40 40 600 7 SB led CR 684 5.20 59/41 100/00 0 8.6 yes
pcff 1275 40 80 600 5 SB led CR 893 6.79 55/45 100/00 0 14.4 yes
pcjj 1275 40 60 600 5 SB led CR 703 5.34 58/42 100/00 4 12.7 yes
pckk 1275 40 100 600 5 SB led CR 1375 10.45 67/33 100/00 489 14.0 yes
dcaa 1275 40 40 600 2 SB led CR 628 4.77 48/52 100/00 41 29.3 yes
pcpp 1275 40 40 1000 5 SB led CR 642 5.46 56/44 100/00 47 12.7 yes
pcqq 1275 40 80 1000 5 SB led CR 718 6.11 51/49 100/00 66 21.5 yes
rcaa 1275 35 40 600 10 SB led CR 531 4.54 66/34 100/00 0 7.1 yes
rcab 1275 35 40 600 5 SB led CR 508 4.34 68/32 100/00 38 13.2 yes
rcff 1275 35 80 600 10 SB led CR 360 3.08 19/81 100/00 0 23.6 yes
rcfb 1275 35 80 600 5 SB led CR 330 2.82 23/77 100/00 0 28.8 yes
rcjj 1275 35 60 600 5 SB led CR 778 6.65 64/36 100/00 0 18.5 yes
rcjb 1275 35 60 600 10 SB led CR 756 6.46 63/37 100/00 0 15.3 yes
rcfc§ 1275 35 80 600 5 SB led CR 278 2.38 22/78 100/00 0 36.0 yes
impa 1325 40 80 600 5 SB led CR 2182 16.58 62/38 100/00 2 12.9 yes
imra 1325 35 80 600 5 SB led CR 904 7.73 75/25 100/00 3 16.9 yes
ppra 1375 40 80 600 5 SB led CR 680 5.17 88/12 100/00 8 40.9 yes
Higher mantle Tp; Strong LCC (An75)
pprb 1425 40 80 600 5 SB; limited peeling-off (drip-offs); CR 1300 9.88 52/48 48/52 40 78.8 yes
pprc 1475 40 80 600 5 SB; peeling-off (drip-offs); CR 1902 14.46 28/72 23/77 60 126.6 -
pprd 1525 40 80 600 5 SB; peeling-off (drip-offs); CR 6421 48.80 008/92 005/95 85 131.8 -
ppre 1475 40 10 600 5 very shallow SB; CR 524 3.98 51/49 100/00 45 72.9 -
pprf 1525 40 10 600 5 very shallow SB; CR 154 1.17 86/14 78/22 36 14.1 -
pprg 1475 40 20 600 5 very shallow SB; CR 243 1.85 100/0 100/00 2 16.9 -
pprh 1525 40 20 600 5 very shallow SB; CR 238 1.81 87/13 78/22 0 65.4 -
ppri 1525 40 80 1000 5 very shallow SB; CR 317 2.70 55/45 100/00 - 43.3 -
Higher mantle Tp; Strong LCC (An75) with eclogitization†
eprd 1525 40 80 600 5 SB; peeling-off (drip-offs); CR 41510 315.49 008/92 001/99 75 81.9 yes
eprg 1475 40 20 600 5 SB; peeling-off (drip-offs); CR 11651 88.55 14/86 002/98 50 104.9 yes
eprh 1525 40 20 600 5 SB; peeling-off (drip-offs); CR 39675 301.54 012/88 00/100 335 103.0 yes
eprj 1525 40 20 1000 5 SB; peeling-off (drip-offs); CR 37696 320.58 16/84 002/98 207 111.5 yes
eprl** 1525 40 80 600 5 SB; peeling-off (drip-offs); CR 37894 288.01 19/81 001/99 8 44.9 yes
eprm** 1475 40 20 600 5 SB; peeling-off (drip-offs); CR 35172 267.32 16/84 001/99 10 55.3 yes
Higher mantle Tp; Mafic UCC with LCC (An75) eclogitization†
amcba 1525 40 80 600 5 subduction with episodic SB; CR - - - - - - -
amceb 1525 40 80 600 5 SB; peeling-off (drip-offs); CR - - - - - - -
Present mantle Tp; Weak LCC (WQ)
wdaa# 1275 40 40 600 10 no SB; coherent peeling-off; CR 8382 63.71 003/97 00/100 0 40.1 -
wdaa 1275 40 80 600 10 no SB; coherent peeling-off; CR 9597 72.94 011/89 00/100 0 26.7 -
wdbb 1275 40 100 600 10 no SB; coherent peeling-off; CR 10725 81.51 012/88 001/100 0 29.4 -
wdee 1275 40 80 600 7 no SB; coherent peeling-off; CR 10032 76.25 011/89 00/100 17 30.4 -
wdff 1275 40 100 600 7 no SB; coherent peeling-off; CR 11181 84.98 014/86 00/100 42 34.5 -
wdgg 1275 40 100 600 5 no SB; coherent peeling-off; CR 11340 86.19 012/88 00/100 9 37.3 -
wdhh 1275 40 80 600 5 no SB; coherent peeling-off; CR 9869 75.01 012/88 00/100 29 33.6 -
Supplementary Table 1. Model-conditions and results of 2D numerical experiments for orogenic continental recycling.
Net ϕ
Continental recycling (CR) magnitude
Cooling
age (Myr)
Length (km)
UCC/
LCC (%)
Recy.
Vol. (km3/
km)
Sed.
(km3/
km)
used in
ϕT p -ξ
calc
Result break-off /
peeling-off
recy. (%)
t recy
(Myr)
Model
Mantle
Poten.
Temp. (K)
Cont.
thick. (km)
Oceanic plate Net
subduc.
Vel. (cm/a)
16
Higher mantle Tp; Weak LCC (WQ)
wprb 1425 40 80 600 5 SB; coherent peeling-off; CR 13850 105.26 006/94 008/92 28 30.2 -
wprc 1475 40 80 600 5 SB; coherent peeling-off; CR 16093 122.31 006/94 009/91 29 25.5 -
wprd 1525 40 80 600 5 SB; coherent peeling-off; CR 17912 136.14 005/95 007/93 128 36.7 -
wpre 1475 40 10 600 5 SB; coherent peeling-off; CR 15296 116.25 003/97 002/98 442 39.3 -
wprg 1475 40 20 600 5 SB; coherent peeling-off; CR 12565 95.50 004/96 004/96 57 25.6 -
wprh 1525 40 20 600 5 SB; coherent peeling-off; CR 12588 95.67 004/96 003/97 3 19.3 -
* Crustal melting absent§ Thermally 100 km wide ocean-continent transition. In all other models, 200 km width is used.† Gabbroic LCC (3000 kg/m3). In all other models, LCC is mafic continental crust (2800 kg/m3).** Higher radioactive heat (H r ) generation. Crust/sediments H r increased by 2.25x (eprl ) and 1.75x (eprm ). Mantle H r increased by 1.5x.a,b Dominantly mafic UCC (2850 kg/m3) with stronger (An75) rheology in amcb and weaker (WQ) rheology in amce. Recycling fluxes are not calculated for these models.
Net ϕ
Continental recycling (CR) magnitude
Cooling
age (Myr)
Length (km)
UCC/
LCC (%)
Recy.
Vol. (km3/
km)
Sed.
(km3/
km)
used in
ϕT p -ξ
calc
Result break-off /
peeling-off
recy. (%)
t recy
(Myr)
Model
Mantle
Poten.
Temp. (K)
Cont.
thick. (km)
Oceanic plate Net
subduc.
Vel. (cm/a)
17
Supplementary Table 1. Model-conditions and results of 2D numerical experiments for orogenic continental recycling.