*Manuscript Click here to view linked References
1 2
Late Palaeozoic to Mesozoic kinematic history of the
3
Talas-Ferghana strike-slip Fault (Kyrgyz West Tianshan)
4
as revealed by 40Ar/39Ar dating of syn-kinematic white mica
5 6
Yann Rolland1*, Dmitriy V. Alexeiev2, Alfred Kröner3, Michel Corsini1, Chloé Loury1,
7
Patrick Monié4
8 9
1
Géoazur, Observatoire de la Côte d’Azur, Université de Nice Sophia-Antipolis, 250 rue Albert
10
Einstein, Sophia Antipolis, 06560 Valbonne, France (
[email protected]) *
11
2
Geological Institute, Russian Academy of Sciences, Pyzhevskiy 7, 119017, Moscow, Russia
12
3
Institut für Geowissenschaften, Universität Mainz, 55099 Mainz, Germany
13
4
Géosciences Montpellier, UMR-CNRS 5243, Université de Montpellier 2, Place Eugène
14
Bataillon, 34095 Montpellier Cedex 05, France.
15 16
*Corresponding author
17 18
1
19
Abstract
20
The NW-trending Talas-Ferghana Fault (TFF) in Kyrgyzstan, Central Asia, is one of the
21
largest intracontinental strike-slip faults in the world. It extends over a distance of more than
22
2000 km from southern Tourghai to western Tarim and exhibits a maximum dextral offset of
23
~200 km during the late Palaeozoic to present. The history of the Fault provides important
24
insights for the understanding of the evolution of southern Central Asia but remains poorly
25
constrained due to lack of reliable geochronological data. We present new Ar-Ar ages and
26
structural data from the Kyrgyz West Tianshan, that elucidate the kinematic history of the TFF in
27
the Palaeozoic and Mesozoic.
28
deformational history consisting of several episodes. Two late Carboniferous ages of 312 ± 4 Ma
29
and ca 317 Ma point to initiation of top-to-the-south and dextral transpressional deformation
30
during a metamorphic overprint in Precambrian and Palaeozoic rocks along the northern
31
compartment of the TFF. A second episode of shearing during the early Permian is revealed in
32
the same area at ~290 Ma, though the sense of motion remains unconstrained. The main phase of
33
dextral motion along the entire Fault occurred in the late Permian and Early Triassic as shown by
34
ages of 256 ± 4 and 250 ± 4 Ma obtained at two different locations in the NW and central parts
35
of the TFF. Partial isotopic resetting occurred between 240 and 210 Ma and younger ages of
36
400 inherit. ~317 metam. < 210 reset
88
70 75
Karabura pass
50
K10-17A & B Def. granite: ~289 inherit. 256 shearing 242 shearing < 200 reset
PR2-O2 Shale, chert
42°10’N
10
PR2? Felsic gneiss PR2 & PZ3 granites
85
75
South Tianshan: S-C2 Shale, carbonate, chert, basalt, schist P1-2 Molasse deposits
PZ3
sh
Structures
D2-C2
Paleozoic thrusts h r. C
71°30’E 41°50’N
D2-C2 Sandst., carbonate
PR2?
10
70 60
PR2
la nda Sa
Middle Tianshan:
PR2-O2 g s hta ymy r. K
PR2?
42°10’N
42°20’N
5
PR2?
r.
O3-S1 & D1 granites
PR2-PZ1?
45
a tk
al
5 km
72°45’E
3a
71°45’E
73°00’E
Cenozoic thrusts Main fold axes
41°50’N
Toktogul Reservoir
K10-4D Sheared metapelite: > 270 inherit. 250 shearing < 200 reset
PR2 ?
80 5
70 80
70 10
20
75
41°40’N
r. K
PR2?
u a ra s
20
40
75 75 72 80 80 80
PR2
3
80
mineral/stretching lineation 41°40’N
85
C1-2 PR2-O2
r. Ka ind ys u 72°45’E
5 km
metamorphic cleavage shear band
NL
P1-2 S-C2
Bedding
75
K10-5A Micaschist: 312 shearing K10-5D Cross-cutting dyke 195 intrusion
TFF
30
TFF 73°00’E
Fig. 3 Rolland, et al.: Ar-Ar Talas - Ferghana Fault
3b
crenulation lineation
Figure 4
TFF
NE
1 km
SW
1 km
metamorphic cleavage
TFF
Cenozoic deposits
North Tianshan:
Middle Tianshan:
conglomerate/coarse pelites fine grained pelites
PR2-O2 Shale, chert PR2-PZ1? Phyllite, turbidite
limestones
PR2 & PZ3 granites marls
fine grained pelites
PR2? Greenschist, phyllite marls
PR2? Greenschist, marble
Figure 5 Click here to download high resolution image
Figure 6 Click here to download high resolution image
B
Figure 7
A
Qtz phe
Kfs
S
S Pl C
C‘ phe
Pl
S
C
D
Kfs
phe
phe C‘
Pl
S
Qtz phe
E
F S C
Cal
S C
H
G Ms
Ms St
Pl
C’ C’
Bt
Bt
Figure 8
A
N
N
B
Best plane : 120,6 SW 74,4
great circle: 109,0 S 84,9, Axis of its pole : 19,0 N 5,1
Mean lineation value : 121,8 SE 68,0
Shear zones mineral and stretching lineations axes
poles to shear planes
N
N
great circle : 21,2 W 66,9,
C
Shear zones mineral lineations
D great circle : 96,3 S 60,9, Axis of its pole : 6,3 N 29,1
Best crenulation axis : 104,5 E 14,4 Fold axis: 111,2 E 23,1
Crenulation
Bedding
crenulation/intersection lineation axes
poles to bedding
N
N
E
F great circle : 109,9 S 67,8, Axis of its pole : 19,9 N 22,2
Best plane: 108,5 S 85,5
poles to foliations
Foliation
Stretching lineation mineral and stretching lineations axes
Figure 9
N
N
A
B
Right-lateral Top-South
Stretching lineations
Veins foliation with main top-south component foliation with main right-lateral component
Figure 10
390
K10-4D
360 330
Age [ Ma ]
Age [ Ma ]
300 270 240 210 250.36 ± 3.52 Ma
180 150 120 90 60 30
0
10
20
30
40
50
60
70
80
90
570 540 510 480 450 420 390 360 330 300 270 240 210 180 150
100
K10-18
317.36 ± 3.75 Ma
0
Cumulative 39Ar Released [ % ] K10-17A
600 500
Age [ Ma ]
Age [ Ma ]
550 450 400 350
256.16 ± 3.94 Ma
300 250 200 150 100 50 0
10
20
30
40
50
60
70
80
90
100
420 400 380 360 340 320 300 280 260 240 220 200 180 160 140
50
60
70
80
90
100
241.6± 2.8 Ma 289.12 ± 3.35 Ma
0
500
280
450
260
400
240
350
Age [ Ma ]
Age [ Ma ]
40
10
20
30
40
50
60
70
80
90
100
Cumulative 39Ar Released [ % ]
K10-5D
195.03 ± 2.58 Ma
220
30
K10-17B
Cumulative 39Ar Released [ % ] 300
20
Cumulative 39Ar Released [ % ]
700 650
10
200 180
300 250
311.64 ± 3.97 Ma
200
160
150
140
100
120
50
100
K10-5A
0 0
10
20
30
40
50
60
70
80
90
Cumulative 39Ar Released [ % ]
100
0
10
20
30
40
50
60
70
80
90
100
Cumulative 39Ar Released [ % ]
Table 1
Table 1. Summary of sample localities and Ar-Ar ages. Sample
Locality
Coordinates
Rock / setting
Mineral
Ar ages (Ma) and age meaning
K10-4D
Ferghana ridge road Biskek Osh
41°41'59.8"N 72°56'08.5"E
Sheared metapelite, SW wall of TFF
Phengite, recrystallised in shear zone
250 ± 4 - age of shearing of TFF ≥270 - inheritance ≤200 - reset
K10-5A
Ferghana ridge r. Karasu
41°40'47.8"N 73°00'03.2"E
Micaschist, NE wall of TFF
Muscovite in micaschist
312 ± 4 - age of ductile amphibolite facies dextral transpressive deformation
K10-5D
Ferghana ridge r. Karasu
41°40'47.8"N 73°00'03.2"E
Pegmatite dyke crosscutting micaschist, NE wall of TFF
Muscovite in pegmatite dyke
195 ± 3 – right-lateral transtensive shearing and pegmatite emplacement
K10-17A
Talas ridge, 200 m SW of Karabura pass
42°12'07.7"N 71°34'46.5"E
Deformed granite C3P1, SW wall of TFF
Phengite formed at the expanses of feldspars
256 ± 4 - age of shearing of TFF ≤200 - reset
K10-17B
Talas ridge, 200 m SW of Karabura pass
42°12'07.7"N 71°34'46.5"E
Deformed granite C3P1, SW wall of TFF
Phengite formed at the expanses of feldspars
ca. 242– age of shearing of TFF ≥ 289 ± 7 - inheritance ≤200 - reset
K10-18
Talas ridge, ~1 km N of Karabura pass
42°13'10.8"N 71°34'25.5"E
Low green-schist metapelite, Karabura fm. NE wall of TFF
Phengite, recrystallised from pelitic sediment matrix
≥ 400 –inherited age 317 ± 8 – earliest deformations ≤210 - later motion in Triassic
Table 2
Table 2. Summary results of 40Ar/39Ar dating of white micas from the Talas-Ferghana Fault zone. Step N°
Laser power
36Ar(a)
37Ar(ca)
38Ar(cl)
39Ar(k)
Age ± 2s (Ma)
40Ar(r)
40Ar(r) (%)
39Ar(k) (%)
K/Ca ± 2s
Phengite K10-4D. J = 0.00392580. Age (steps 9-11): 250.36 ± 3.57 Ma (MSWD: 3.31, 45.5 % 39Ar. Total Fusion Age: 237.8±4.8 Ma. 1
510.00 W
0.000010
0.000078
0.000011
0.000408
0.006467
109.03 ± 37.07
67.75
0.27
442 ± 811
2 3 4 5 6 7 8 9 10 11 12
680.00 W
0.000012
0.000299
0.000024
0.002550
0.062089
164.68 ± 11.43
94.33
1.69
716 ± 413
800.00 W
0.000001
0.000344
0.000025
0.003284
0.081449
167.61 ± 9.62
99.44
2.17
802 ± 336
950.00 W
0.000005
0.001656
0.000035
0.009058
0.273484
202.09 ± 4.67
100.42
6.00
460 ± 61
1100.00 W
0.000004
0.001376
0.000000
0.013151
0.424936
215.46 ± 4.84
99.62
8.71
803 ± 72
1250.00 W
0.000007
0.000785
0.000021
0.009370
0.316126
224.39 ± 4.89
100.61
6.20
1002 ± 135
1400.00 W
0.000006
0.000390
0.000000
0.007877
0.269712
227.53 ± 5.31
100.60
5.22
1695 ± 495
1750.00 W
0.000021
0.000293
0.000031
0.022261
0.797355
237.36 ± 4.75
100.71
14.74
6376 ± 2879
2000.00 W
0.000031
0.000280
0.000032
0.030117
1.119202
245.68 ± 4.84
100.76
19.94
9050 ± 6167
2250.00 W
0.000033
0.000399
0.000021
0.022674
0.863940
251.49 ± 4.98
101.07
15.01
4769 ± 1292
2550.00 W
0.000006
0.000509
0.000031
0.015867
0.612695
254.64 ± 5.25
100.24
10.50
2619 ± 684
3000.00 W
0.000007
0.002403
0.000093
0.014430
0.593759
270.16 ± 5.56
100.29
9.55
504 ± 42
Muscovite K10-5A, J = 0.02045940. Age (steps 11-19): 311.64 ± 3.97 Ma (MSWD: 0.26), 95.2% 39Ar. Total fusion age: 311.8 ± 5.3 Ma. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
420.00 W
-
16.531012
0.000000
-
440.00 W
0.001849
12.177302
0.000000
-
460.00 W
-
-
0.067311
480.00 W
-
500.00 W
0.010903
-
0.047876
0.521236
3.414242
226.89 ± 612.49
520.00 W
0.010198
-
0.019581
1.650236
11.028768
231.21 ± 233.97
540.00 W
-
-
0.000000
0.037195
5.730477
560.00 W
-
-
0.004329
0.064837
3.756231
580.00 W
0.028707
-
0.031314
4.068102
36.521412
600.00 W
-
12.033729
0.000000
2.090419
22.552471
620.00 W
0.011330
0.795445
0.000000
3.838415
640.00 W
0.005724
7.394720
0.000000
660.00 W
0.010434
12.914314
0.000000
680.00 W
0.016573
1.976279
700.00 W
0.028827
11.837202
720.00 W
0.029344
-
790.00 W
0.033693
4.110604
930.00 W
0.036453
4.109622
0.078899
4.175316
31.167972
1130.00 W
0.049239
2.450959
0.170566
49.393627
454.969469
5.030145
-
7381.64
-
-
2284.53 #######
277.26
-
-
3.590632
1107.93 #######
1396.66
0.05
-
3.720220
-
2699.96
-
-
51.07
0.30
-
78.09
0.95
-
2568.30 #######
590.40
0.02
-
1410.33 #######
456.00
0.04
-
304.21 ± 93.83
80.78
2.33
359.82 ± 149.29
112.59
1.20
0.028 ± 0.048
34.761478
306.66 ± 104.77
90.86
2.20
0.780 ± 19.965
7.113427
66.600944
316.18 ± 48.11
97.20
4.07
0.155 ± 0.356
7.600161
69.766336
310.50 ± 35.78
95.43
4.35
0.095 ± 0.158
0.037433
10.697314
97.991469
309.90 ± 26.59
94.90
6.13
0.875 ± 8.314
0.000000
5.644977
48.428892
291.74 ± 52.39
84.66
3.23
0.077 ± 0.144
0.064342
15.137191
135.707816
303.83 ± 24.50
93.64
8.67
0.164934
62.558649
579.993049
313.34 ± 7.78
97.99
35.83
2.459 ± 15.278
256.41 ± 120.64
73.90
2.39
0.164 ± 0.785
311.48 ± 9.28
96.57
28.29
3.257 ± 27.662
0.000000
0.086626 -
1.568314 -
-
-
Muscovite K10-5D, J = 0.02046510. Age (steps 5-10): 195.03 ± 2.58 Ma (MSWD: 0.52), 98.52% 39Ar. Total fusion age: 195.0 ± 2.8 Ma. 1
420.00 W
0.001363
10.383223
0.000000
2 3 4 5 6 7 8 9 10
500.00 W
0.007737
10.686632
0.000000
0.165351
-
1.145092
550.00 W
0.017348
20.319972
0.000000
1.572986
4.614678
600.00 W
-
1.343178
0.000000
2.619279
19.499023
650.00 W
-
-
0.065079
29.246244
700.00 W
0.012346
-
0.017605
750.00 W
-
8.981221
0.000000
800.00 W
0.020135
3.504014
850.00 W
0.018770
2.223892
1111.00 W
0.038017
20.630331
0.255835
-
73.91 56.24 #######
-
-
9.95
0.06
0.00 ± 0.01
105.19 ± 155.98
46.89
0.55
0.01 ± 0.01
255.83 ± 131.26
123.73
0.91
0.32 ± 6.70
167.737237
200.22 ± 12.85
101.01
10.15
-
32.361280
179.654101
194.14 ± 14.93
97.48
11.23
-
20.691953
115.737314
195.52 ± 13.40
100.18
7.18
0.37 ± 0.81
0.000000
23.259990
125.596444
189.09 ± 12.03
94.93
8.07
1.07 ± 6.24
0.000000
12.421889
64.614618
182.50 ± 26.95
91.54
4.31
0.90 ± 10.66
0.068053
165.966709
928.564848
195.57 ± 4.33
98.28
57.59
1.30 ± 1.17
56.06
0.15
118 ± 180
Phengite K10-17A, J = 0.00391660. Age (steps 5-6): 256.16 ± 3.94 Ma (MSWD: 2.86) 70.4% 39Ar. Total fusion age: 247.2 ± 5.4 Ma. 1
400.00 W
0.000014
0.000076
0.000008
0.000107
0.005214
314.65 ± 182.94
2 3 4 5 6
550.00 W
0.000011
0.001201
0.000027
0.007010
0.213806
203.59 ± 5.00
98.36
10.00
490 ± 68
580.00 W
0.000003
0.000007
0.000000
0.003738
0.122171
217.33 ± 7.68
100.52
5.33
43884 ± 707
640.00 W
0.000020
0.000103
0.000000
0.009907
0.361907
241.26 ± 5.59
101.62
14.13
8087 ± 87
710.00 W
0.000028
0.000129
0.000001
0.019930
0.765452
252.81 ± 5.43
101.02
28.44
13011 ± 92
1111.00 W
0.000025
0.000389
0.000129
0.029397
1.159159
259.08 ± 5.06
100.56
41.94
6349 ± 26
Phengite K10-17B, J = 0.00391660. Age (steps 13-15): 289.12± 3.35 Ma (MSWD: 1.41), 18.7 % 39Ar. Total fusion age : 256.0 ± 5.0 Ma. 1
420.00 W
0.000019
0.003637
0.000079
0.020227
0.622176
205.22 ± 4.29
98.99
6.73
467 ± 39
2 3 4 5 6 7 8 9 10 11 12 13 14 15
450.00 W
-
0.001100
0.000004
0.017985
0.572051
211.81 ± 4.61
100.31
5.98
1373 ± 341
480.00 W
-
-
0.000019
0.019967
0.730931
241.72 ± 4.93
100.95
6.64
-
524.00 W
-
-
0.000009
0.021611
0.789981
241.39 ± 4.82
100.81
7.19
-
555.00 W
-
-
0.000021
0.031789
1.193975
247.60 ± 4.87
100.67
10.57
-
575.00 W
-
-
0.000038
0.045784
1.774623
254.98 ± 4.97
100.70
15.22
-
583.00 W
-
-
0.000008
0.011932
0.470646
259.17 ± 5.50
100.89
3.97
-
602.00 W
-
-
0.000016
0.014687
0.582035
260.31 ± 5.27
100.78
4.88
-
621.00 W
-
-
0.000027
0.019376
0.778437
263.63 ± 5.16
100.69
6.44
-
635.00 W
-
-
0.000026
0.012966
0.528782
267.34 ± 5.56
101.70
4.31
-
655.00 W
-
-
0.000041
0.012771
0.524572
269.12 ± 5.58
101.09
4.25
-
680.00 W
-
0.000013
0.000075
0.015568
0.648955
272.83 ± 5.37
101.03
5.18
722.00 W
-
0.000560
0.000189
0.019793
0.866529
285.51 ± 5.58
100.38
6.58
2971 ± 889
722.00 W
-
0.000153
0.000062
0.005583
0.250753
292.32 ± 6.79
100.45
1.86
3066 ± 4089
1200.00 W
0.000011
0.001032
0.000287
0.030712
1.370278
290.56 ± 5.52
99.70
10.21
2499 ± 404
-
Phengite K10-18, J = 0.00391190. Age (steps 13-15): 317.36 ± 3.75 Ma (MSWD: 0.04), 16.6 % 39Ar. Total fusion age : 286.5 ± 5.8 Ma. 1
500.00 W
-
0.002547
0.000012
0.010174
0.325701
212.87 ± 5.71
100.75
7.19
336 ± 31
2 3 4 5 6 7 8 9
550.00 W
-
0.000394
0.000026
0.014371
0.530026
243.13 ± 5.81
101.71
10.15
3065 ± 1146
600.00 W
-
-
0.000000
0.015684
0.609000
255.11 ± 5.51
101.28
11.08
-
650.00 W
-
-
0.000027
0.017731
0.738990
272.48 ± 5.60
101.28
12.53
-
700.00 W
-
-
0.000033
0.020174
0.925157
297.67 ± 6.02
101.19
14.25
-
750.00 W
-
-
0.000050
0.036407
1.723145
306.46 ± 6.05
100.97
25.72
-
800.00 W
-
-
0.000015
0.018187
0.892959
316.95 ± 6.29
101.83
12.85
-
850.00 W
-
-
0.000019
0.005317
0.261870
317.87 ± 7.10
101.33
3.76
-
1111.00 W
0.000000
0.000129
0.003486
0.221105
399.83 ± 9.73
99.89
2.46
0.000564
520 ± 147
