Journal of Geological ResearchVolume 2012 (2012), Article ID 287962, 11 pagesdoi:10.1155/2012/287962

Research Article

Geochronology and Tectonic Evolution of the Lincang Batholith in Southwestern Yunnan, China

Hongyuan Zhang,1,2 Junlai Liu,1,2 and Wenbin Wu²

¹State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China²Faculties of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China

Received 15 February 2012; Accepted 5 April 2012

Academic Editor: Quan-Lin Hou

Copyright © 2012 Hongyuan Zhang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract.

Geochronological research of the Lincang Batholith is one key scientific problem to discuss the tectonic evolution of the Tethys. Two granitic specimens were selected from the Mengku-Douge area in the Lincang Batholith to perform the LA-ICPMS Zircon U-Pb dating based on thorough review of petrological, geochemical, and geochronological data by the former scientists. Rock-forming age data of biotite granite specimen from Kunsai is about 220 Ma, the Norian age. However, the west sample from Mengku shows 230 Ma, the Carnian age. The later intrusion in Kunsai area located east to the Mengku area shows directly their uneven phenomena in both space and time and may indirectly reflect the space difference of the contraction-extension transformation period of the deep seated faults. Considering the former ⁴⁰Ar/³⁹Ar data and the outcrop in Mengku, the Lincang Batholith should have experienced one tectonic exhumation and regional subsidence cycle. The regional subsidence cycle has close relations to the expansion of the Meso Tethys.

1. Introduction

The Sanjiang-Indochina region is one key area to study the evolution of the Tethys [1–10] (Figure 1). The Changning-Menglian zone was considered as the major faunal break between Gondwanan assemblage to the west and Cathaysian to the east [11, 12]. The subduction-related magmatism occurred along the western edge of the Lanping-Simao-Indochina terrane throughout the Triassic and the closure of Palaeo-Tethys [12, 13]. The Lincang Batholith extends ~370 km from north to south, covering the Chiangrai-Chiang Mai region of Thailand, with an area of more than 10000 km² (Figure 2). It has been shown by many authors that there is great mineral potential [14].

Figure 1: Map of plate tectonics and ore-forming metals in the southern Sanjiang and Indochina peninsula. (a) Scope of Tethys and zone divisions; (b) research area and distribution of major metals: (1) Changning-Menglian-Chiangmai PaleoTethys Suture (time and space after [1, 21, 22]); (2) Ailaoshan-Song Ma Paleo-Tethys Suture (time and space after [2, 6, 8]); (3) Bangong Co-Nujiang Meso-Tethys Suture (time and space after [5]); (4) Yanlung Tsangpo-Naga-Arakan New-Tethys Suture (time and space after [22, 23]); (F1) Nujiang-Saging Fault Zone; (F2) Ranong Fault Zone; (F3) Three Tower Fault Zone; (F4) Tonle Sap Fault Zone; (F5) Đà Lat-Bianhe Fault Zone; (F6) Điên Biên Phú Fault Zone; (F7) Changshan-Da Nang Fault Zone; (F8) Lanjiang Fault Zone; (F9) Ailaoshan-Red River Fault Zone; (F10) Xianshuihe-Xiaojiang Fault Zone; (F11) Lancang-Jinghong Fault Zone.

Figure 2: Regional map of Indian Period and research locality in western Yunnan. The distribution of metal deposits also indicates that there is an important boundary along the Lincang Granite Batholith. Stereographic maps of lower hemisphere projection indicating the initial occurrence of Lincang granite Batholith are also plotted in the regional map. L, S, Q refer to joints parallel to the initial foliation, parallel to the flow direction but upright to the initial foliation, upright to both the flow direction and initial foliation. Orientation of shear fractures can be generated by local stress system of the Batholith with emplacements [24].

The Lingcang Batholith was divided into three lithologic intervals by previous authors, the Xiaojie, Lincang, and Menghai intervals (Figure 2) [15–17]. The major intrusion is porphyritic monzonitic granite, which mainly contains quartz, zonal plagioclase, K-feldspar, and biotite. In addition, geochemical studies have shown that the granite mainly has source features of the crust mixing origin [16, 18].

The Lingcang Batholith was proposed to form in a passive continental margin according to geochemical research [19]. The intrusive timing spans from late Permian to late Triassic based on whole-rock Rb-Sr, mineral ⁴⁰Ar/³⁹Ar, whole-rock ⁸⁷Sr/⁸⁶Sr, Rb-Sr, Sm-Nd, and some other methods (Table 1).

Table 1: Isotopic age data for the Lincang Batholite in the earlier stage.

Lithologic section
Lithology
Measured objects and methods
Dating results, Ma
Sample positions
Testers and the time

Xiaojie
Granite porphyry
Whole-rock (Rb-Sr)

Laomaocun
Zhang et al., 2006 [25]

Xiaojie
Monzonitic granite
Whole-rock (⁸⁷Sr/⁸⁶Sr)
279
Yun County
Chen, 1991 [26]

Lincang
Biotite granite
Biotite (⁴⁰Ar/³⁹Ar)

Near the Lancangjiang River
Dai et al., 1986 [27]

Lincang
Monzonitic granite
Whole-rock (Rb-Sr)
279
Lincang
Chen, 1991 [26]

Lincang
Medium-grained equigranular granodiorite
Whole-rock (Rb-Sr)
263.8
Milestone along Lincang-Mengku road 327–387 km
Zhang et al., 1990 [28]

Lincang
Unequal-sized biotite granite
Whole-rock (Rb-Sr)
193
Shangyun-Xiaotang
Zhang et al., 1990 [28]

Lincang
Monzonitic granite
Whole-rock (Rb-Sr)

Lincang
Liu et al., 1989 [18]

Menghai
Monzonitic granite
Whole-rock (⁸⁷Sr/⁸⁶Sr)
279
Menghai
Chen, 1991 [26]

Menghai
Monzonitic granite
Biotite (Rb-Sr)
256
Menghai
Wang, 1984 [29]

But there are also some understanding differences on the crystallization period and evolution time of the Lincang Batholith. Many predecessors discussed mineral diagenesis and tectonic evolution through traditional data [16, 20], although, not from the viewpoint of the plate tectonics. On scientific problems of the Lincang Batholith, some solutions were put forward such as single period of mixed granite [16], quasi-situ metasomatic granite [20], or Neoproterozoic type I granite complex batholith with multiperiod transforming events [19].

Therefore, the formation and evolution of the Lincang Batholith is still the key to discuss the regional tectonic evolution of the Baoshan and Lanping-Simao-Indochina block. In this study, we conducted petrographic analysis of the Lincang Batholith and provide new LA-ICP-MS U-Pb data in order to constrain the tectonic evolution of the Batholith. We discuss these results of dating in the context of regional tectonic evolution.

2. Dating Methods, Specimens, and Results

2.1. Dating Methods

The U-Pb zircon age dating of monzonitic granite samples selected from the Mengku-Douge research area in Lincang segment (Figures 2 and 3) was designed and completed in the Institute of Geology and Geophysics, Chinese Academy of Sciences. Jobs of single zircon grain micro-area U-Pb geochronological analysis were taken through Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS) of 7500a-type producted by Agilient Co. Ltd., with which the laser beam diameter is 60 μm, the erosion frequency is 8 Hz, the energy density is 15~20 J·cm⁻², the erosion time is about 60 s. For detailed analysis procedures, please see Xu et al. [32]. The Zircon U-Pb isotope and the U, Th data processing are finished by software Glitter4. 0 [33], and computing of U-Pb concordia diagrams, weighted average ages and graphics were completed by software Isoplot3.0 [34].

Figure 3: Geological sketch map in Mengku-Douge area (revised after [15–17, 30, 31]) (1) Area of ingression sea of the Meso-Tethys; (2) Jurassic terrigenous sediments; (3) Early Jurassic volcanic sedimentary rocks; (4) Lincang Triassic granite rock; (5) deep metamorphic wedge with local granodiorite quality migmatization Late Paleozoic; (6) schistosity occurrence; (7) bedding occurrence.

2.2. Specimens

2.2.1. Specimen from Kunsai Quarries

The biotite monzonitic granite samples were selected from the Kunsai quarries to the east of Quannei-Douge migmatite rock belt (Figures 3 and 4(a)). The north part of the rock unit is plunged into the Jurassic basin (Figure 3). Field study shows that both the rock unit and the Jurassic basin have experienced a period of ductile transformation events. The microstructure study shows brittle deformed feldspar (Figures 4(b) and 4(c)), dynamically recrystallized quartz (Figure 4(c)), microdeflected biotite (Figure 4(d)), zircon grains with relatively intact crystal, long column, some rounded output and a higher degree of porosity which is symbiotic to microcline grains (Figure 4(b)). The cathode luminescence (CL) images show that the typical magmatic zircon characteristics are colorless and transparent here with oscillatory zoning, the length of about 120 μm–420 μm and the aspect ratio of 1.2 to 4.1 (Figure 4(e)). Totally, for 22 points of 22 zircon grains of sample biotite granodiorite KS-2 from the Kunsai quarries we performed U-Pb isotope analysis in order to statistically gain a feasible dating result (Figure 4(f)). All points were selected on the edge of long- column euhedral grains where the magmatic zircon oscillatory zoning is clear.

(a)

(b)

(c)

(d)

(e)

(f)

Figure 4: Geochronological research of granite sample KS-2. (a) Position photo of the biotite monzonitic granite sample in the field of Kunsai Quarry. (b) The zircon grows together with the microcline CPL. (c) The microstructure of complete recrystallized quartz indicates the rock once experienced high-greenschist facies of deformation, CPL. (d) One biotite crystal is folded, PPL. (e) Magmatic zircon is shown by the SEM cathodoluminescence (CL) image. The circled area is deduced to form during the crystallization of granite and is just the measured area by laser-ICPMS (f) Zircon La-ICPMs U-Pb dating figure, and the average age is about 220 Ma.

2.2.2. Specimens from Mengku Quarries

The monzonitic granite sample MK-4 is selected from the Mengku East Quarry at the eastern side of the Mengku Town in the Shuangjiang County, which separates Jurassic red clastic rocks with one bedding bottom granitic conglomerate by the paleo-weathering crust in between (Figures 5(a), 5(b), and 5(c)). Figure 5(a) shows the position photo of the biotite monzonitic granite sample in the Mengku East Quarry. From the field outcrop, both granitic intrusion (lower left) and its weathering top can be found to be cleavaged which had been covered by the upper Jurassic red detrital sediments with terrigenous origin, namely, the Huakaizuo Formation. The MK-4 zircon grains (Figure 5(d)) change greatly and have different shapes and sizes, such as long column, fan, and irregular granular. However, size of zircon grains is uniform with length between 90 μm and 150 μm and length-width ratio in 1.1 : 1–1.8 : 1. Zircon grains develop with quartz, plagioclase in rocks. The rock sample has been affected by weathering, showing retrograde metamorphism (Figure 5(e)). Characteristic oscillatory zoning of typical magmatic zircon is rendered on the cathode CL image. The idiomorphic degree of zircon is high, but some fragmented. On the sample of MK-4, 18 zircon grains and 18 points were analyzed by ICP-MS. Edge of the long-column idiomorphic or the chipped-hypidiomorphic zircon grains, and the clear zone of magmatic zircon oscillatory were always selected to perform the micro isotope analysis (Figure 5(f)).

(a)

(b)

(c)

(d)

(e)

(f)

(g)

Figure 5: Geochronological research of the granite sample MK-4. (a) Position photo of the biotite monzonitic granite sample in a field Quarry of east Mengku. (b) Granitic intrusion (lower left) and its fossil weathering were cleavaged. (c) The red detrital material of terrigenous origin, Huakaizuo Formation in Jurassic, was normal gradational. (d) Granitic intrusions are selected as sample. (e) The micro characteristics of MK-4 and the zircon setting are shown. The zircon grains are associated with quartz and plagioclase and have been degraded by some weathering process, CPL, (f) Magmatic zircon is shown by the SEM cathodoluminescence (CL) image. The circled area is deduced to form during the crystallization of granite and is just the measured area by laser-ICPMS. (g) Zircon La-ICPMs U-Pb dating figure, and the average age is about 245 Ma.

2.2.3. Dating Results

As shown in Figure 4(f) and Table 2, the overall harmony values of KS-2 zircon age data range from 195 Ma to 245 Ma, but some of them are below the U-Pb harmonic line and deviated from the harmony line. This is probably because the micro region selected is too close to the boundary of the zircon grain. Some zircon grains (Figure 5(f)) also have some cracks in and this may also affect the dating result. From the harmonic visible figure, zircon dating values are focused to a range from 210 Ma to 230 Ma, and the average age is about 220 Ma. This means that the crystallization age of the Kunsai quarries biotite granite is about in the late Triassic Norian period.

Table 2: U-Pb isotopic dating for the single grain Zircon from granite of Kunsai.

No.
207Pb/²⁰⁶Pb
207Pb/²³⁵U
206Pb/²³⁸U
208Pb/²³²Th
207Pb/²⁰⁶Pb
207Pb/²³⁵U
206Pb/²³⁸U
208Pb/²³²Th

Ratio
Error (1)
Ratio
Error (1)
Ratio
Error (1)
Ratio
Error (1)
Ratio
Error (1)
Ratio
Error (1)
Ratio
Error (1)
Ratio
Error (1)

A77
0.05789
0.00231
0.25961
0.00949
0.03251
0.00089
0.01383
0.00076
526
38
234
8
206
6
278
15

A78
0.05188
0.00244
0.23562
0.00953
0.03294
0.00079
0.01035
0.00025
280
110
215
8
209
5
208
5

A79
0.05273
0.00141
0.24329
0.00604
0.03345
0.00081
0.01108
0.00055
317
26
221
5
212
5
223
11

A80
0.05213
0.00216
0.23471
0.00801
0.03265
0.00077
0.01025
0.00024
291
97
214
7
207
5
206
5

A81
0.05209
0.00131
0.25938
0.00608
0.0361
0.00086
0.01177
0.00034
289
25
234
5
229
5
237
7

A82
0.05014
0.00118
0.24192
0.00531
0.03498
0.00082
0.01113
0.00044
201
24
220
4
222
5
224
9

A83
0.05126
0.00122
0.24287
0.00541
0.03435
0.00081
0.01155
0.0006
253
24
221
4
218
5
232
12

A84
0.05027
0.00114
0.24534
0.00525
0.03539
0.00083
0.01176
0.00041
207
24
223
4
224
5
236
8

A89
0.0521
0.00237
0.22575
0.00875
0.03143
0.00075
0.00987
0.00023
290
107
207
7
199
5
199
5

A90
0.05305
0.00182
0.2649
0.0084
0.03621
0.00094
0.01376
0.00075
331
33
239
7
229
6
276
15

A91
0.05739
0.00113
0.23972
0.00441
0.03029
0.0007
0.00946
0.00032
507
23
218
4
192
4
190
6

A92
0.05076
0.00135
0.24604
0.00612
0.03515
0.00085
0.01173
0.00045
230
26
223
5
223
5
236
9

A93
0.05089
0.00279
0.24455
0.01197
0.03485
0.00086
0.01098
0.00025
236
127
222
10
221
5
221
5

A94
0.05114
0.00155
0.24377
0.00683
0.03457
0.00087
0.01167
0.00055
247
29
222
6
219
5
235
11

A95
0.05055
0.00109
0.24175
0.00488
0.03469
0.00081
0.01181
0.00045
220
24
220
4
220
5
237
9

A96
0.05018
0.00134
0.23857
0.00594
0.03448
0.00084
0.01149
0.00049
203
26
217
5
219
5
231
10

B02
0.05115
0.00119
0.24774
0.00541
0.03514
0.00084
0.01297
0.00054
248
25
225
4
223
5
260
11

B03
0.05067
0.00224
0.24165
0.00903
0.03459
0.00082
0.0109
0.00025
226
104
220
7
219
5
219
5

B04
0.05104
0.00235
0.24163
0.00953
0.03433
0.00082
0.01081
0.00025
243
109
220
8
218
5
217
5

B05
0.05079
0.00153
0.24968
0.00699
0.03567
0.0009
0.01274
0.00067
231
29
226
6
226
6
256
13

B06
0.05039
0.00095
0.24525
0.00437
0.03531
0.00082
0.01121
0.00038
213
25
223
4
224
5
225
8

B07
0.05429
0.00243
0.27463
0.01035
0.03669
0.00089
0.01147
0.00027
383
103
246
8
232
6
230
5

B08
0.05014
0.00223
0.24399
0.00913
0.0353
0.00085
0.01114
0.00026
201
104
222
7
224
5
224
5

B09
0.05141
0.00105
0.25807
0.00495
0.03643
0.00086
0.01414
0.00053
259
25
233
4
231
5
284
11

As shown in Figure 5(g) and Table 3, the overall harmony values of MK-4 zircon age data range between 190 Ma and 315 Ma. The values are somewhat scattered mainly because the granite of the Mengku quarries has been heavily weathered (Figure 5(d)). During the weathering process, chemical bonds of ZrO₂ in zircon grains of our MK-4 sample would be broken. Therefore, some zircon isotope escaped. The average age of 245 Ma might indicate that the late Permian to early-middle Triassic magmatic event happened in the Mengku Quarries area of the Lincang Batholith.

Table 3: U-Pb isotopic dating for the single grain Zircon from granite of Mengku.

Analysis
207Pb/²⁰⁶Pb
207Pb/²³⁵U
206Pb/²³⁸U
208Pb/²³²Th
207Pb/²⁰⁶Pb
207Pb/²³⁵U
206Pb/²³⁸U
208Pb/²³²Th

no.
Ratio
Error (1)
Ratio
Error (1)
Ratio
Error (1)
Ratio
Error (1)
Ratio
Error (1)
Ratio
Error (1)
Ratio
Error (1)
Ratio
Error (1)

1
0.05174
0.00244
0.32303
0.0139
0.04528
0.00108
0.01152
0.00053
274
56
284
11
285
7
232
11

2
0.09115
0.00288
2.96352
0.08448
0.23585
0.0053
0.08061
0.00287
1450
25
1398
22
1365
28
1567
54

3
0.11509
0.00332
0.50952
0.01225
0.03212
0.00066
0.02102
0.00068
1881
19
418
8
204
4
420
13

4
0.04837
0.00265
0.22077
0.01108
0.03312
0.00085
0.01153
0.00063
117
69
203
9
210
5
232
13

5
0.04837
0.0022
0.27295
0.01145
0.04095
0.00092
0.01223
0.0006
117
57
245
9
259
6
246
12

6
0.05351
0.00279
0.29775
0.01415
0.04038
0.00104
0.01371
0.00078
350
62
265
11
255
6
275
16

7
0.0806
0.00218
2.27431
0.05585
0.2048
0.00394
0.05968
0.00155
1212
22
1204
17
1201
21
1172
30

8
0.0802
0.00341
2.36577
0.09085
0.2141
0.00577
0.05352
0.00277
1202
37
1232
27
1251
31
1054
53

9
0.05928
0.00248
0.29959
0.01132
0.03668
0.00082
0.00966
0.00046
577
45
266
9
232
5
194
9

10
0.04989
0.00375
0.23793
0.0163
0.03461
0.00119
0.00907
0.00072
190
96
217
13
219
7
182
14

11
0.07866
0.00333
0.34683
0.01279
0.032
0.00079
0.01233
0.00063
1164
37
302
10
203
5
248
13

12
0.0406
0.00217
0.22437
0.01119
0.04011
0.00095
0.01052
0.00055
−255
72
206
9
254
6
212
11

13
0.0639
0.00299
0.31538
0.01317
0.03582
0.00089
0.01126
0.00067
738
48
278
10
227
6
226
13

14
0.07481
0.00441
0.3517
0.01817
0.03412
0.00108
0.01178
0.00078
1063
56
306
14
216
7
237
16

15
0.06821
0.00263
0.97745
0.03376
0.10399
0.00236
0.03233
0.00106
875
37
692
17
638
14
643
21

16
0.05116
0.00255
0.26673
0.01227
0.03784
0.00088
0.01057
0.00052
248
64
240
10
239
5
213
10

17
0.05025
0.00304
0.25181
0.01395
0.03636
0.00102
0.01037
0.00064
207
77
228
11
230
6
209
13

18
0.05379
0.003
0.27018
0.01369
0.03645
0.00098
0.00965
0.0006
362
67
243
11
231
6
194
12

19
0.05083
0.00373
0.26778
0.01802
0.03823
0.00125
0.00987
0.00055
233
96
241
14
242
8
199
11

20
0.06022
0.00487
0.2998
0.0217
0.03612
0.00142
0.01137
0.00113
611
90
266
17
229
9
229
23

21
0.0473
0.00214
0.20932
0.0087
0.0321
0.0007
0.00892
0.00038
64
55
193
7
204
4
179
8

22
0.05405
0.00334
0.28442
0.01602
0.03817
0.00111
0.00858
0.0006
373
75
254
13
241
7
173
12

23
0.05907
0.0024
0.66212
0.02439
0.08128
0.00181
0.03438
0.00121
570
43
516
15
504
11
683
24

24
0.05064
0.00245
0.21459
0.00944
0.03072
0.00072
0.00797
0.00046
224
59
197
8
195
5
160
9

25
0.05594
0.00261
0.26352
0.01113
0.03415
0.0008
0.00964
0.00045
450
53
237
9
216
5
194
9

26
0.06769
0.00524
0.32217
0.02212
0.0345
0.00134
0.01049
0.0009
859
80
284
17
219
8
211
18

27
0.06354
0.00206
0.75553
0.02205
0.08618
0.00166
0.02056
0.00084
726
32
571
13
533
10
411
17

28
0.05014
0.00296
0.33191
0.01801
0.04797
0.00129
0.02068
0.0011
201
77
291
14
302
8
414
22

29
0.23782
0.00377
6.55914
0.08439
0.19984
0.00325
0.01824
0.00075
3105
12
2054
11
1174
17
365
15

3. Tectonic Implications

Previous petrological and geochemical studies [18, 26, 28, 35] indicate that the Lincang granite mainly shows two types of granite with an initial strontium isotope ratio ranging from 0.71 to 0.78 and therefore it belongs to S-type granite and once may have been formed in an environment of tectonic collision. Combined with previous chronological data, we propose a three-stage model on the tectonic evolution between late Permian and Jurassic (Figure 6).

Figure 6: Isotopic age histogram showing the major tectonic event in the area east to the Tibet Peateau (after [8]).

(1)  Regional Collision and Contraction before the Formation of the Lincang BatholithBefore the formation of the Lincang Batholith, the Paleo-Tethys Ocean and many intraoceanic islands distributed between the Baoshan and the Lanping-Simao-Indosinian blocks [36]. In a regional contractional environment of subduction and collision, it is extremely common to find folding, thrusting, and uplifting phenomena (Figure 7(a)).

Figure 7: Formation and tectonic evolution model for the Lincang Batholith.

(2)  Time Heterogeneity of In Situ Hybrid of the Lincang BatholithThe Lincang Batholith was controlled by one deep-seated fault along the Lancang Jiang River and proposed in situ hybrid origin of the Batholith in the early to middle Triassic collision between the Baoshan-Shantai and Lanping-Simao-Indochina Blocks [16]. Our study shows an ununiform law result in the aspect of mixing time of the Batholith (Figure 7(b)). The intrusion time in the east Qunsai area was later than in the Mengku area, indicating that the regional contraction in Mengku area was weakened or stopped, and triggered magma poured at ~230 Ma, however, the contraction pattern may still remain in the Qunsai area to the east.

(3)  Tectonic Denudation and Regional Exhumation Happened between Late Triassic and Middle Jurassic, Which Is Supported by ~201 Ma Biotite ⁴⁰Ar/³⁹Ar Age from the Lincang Batholith [27]This paper research shows that the upper part of the Lincang Batholith experienced long-term denudation, resulting in the development of the weathering crust (Figure 7(a)). The upper crust is the Jurassic Huakaizuo Formation, characterized by carbonate rocks of shallow sea facies, together with some volcano clastic rocks (Figure 5(b)). Unconformity relationship is shown between the Batholith and the Huakaizuo Formation (Figures 3, 5(a), 5(b), 5(c), and 7(c)). Apparently, the Meso-Tethys expansion also happened in this era and left some effect in the Lincang Area.

Acknowledgments

The authors appreciate sincerely both the field research and inner discussion together with Professor Yong-Qing Chen from China University of Geosciences (Beijing), Research Fellow Ying-Xiang Lu from Yunnan Bureau of Geology and Mineral Resources, and Research Fellow Fang-Cheng Lin from Chengdu Institute of Geology and Mineral Resources. The authors thank Dr. Pengfei Li from University of Queensland for his perfect academic revision of the paper. The research was supported by the China Geology Survey (no. 200811008, no. 1212011121188), the Ministry of Science and Technology (no. 2006BAB01A03-3), the Chinese National Natural Foundation (no. 90814006) of the People’s Republic, and the China University of Geosciences in Beijing (no. 2-9-2001-280).

References

J. Q. Huang and B. W. Chen, The Evolution of the Tethys in China and Adjacent Regions, Geological Publishing House, Beijing, China, 1987.

P. Jian, D. Liu, A. Kröner et al., “Devonian to Permian plate tectonic cycle of the Paleo-Tethys Orogen in southwest China (II): insights from zircon ages of ophiolites, arc/back-arc assemblages and within-plate igneous rocks and generation of the Emeishan CFB province,” Lithos, vol. 113, no. 3-4, pp. 767–784, 2009.

H. D. Klemme and G. F. Ulmishe, “Effective petroleum source rocks of the world: stratigraphic distribution and controlling depositional factors,” AAPG Bulletin, vol. 75, no. 12, pp. 1809–1851, 1991.

G. T. Pan, Z. L. Chen, and X. Z. Li, Geological Structure Formation and Evolution of East Tethys, Geological Publishing House, Beijing, China, 1997.

G. T. Pan, H. X. Zheng, Y. R. Xu, et al., “A preliminary study on Bangong Co-Nujiang Suture,” in Editing Committee of Geological Memoirs of Qinghai-Xizang Plateau(12)-Geological Tectonics of "Sanjiang", pp. 229–242, Geological Publishing House, Beijing, China, 1983.

X. Wang, I. Metcalfe, P. Jian, L. He, and C. Wang, “The Jinshajiang-Ailaoshan Suture Zone, China: tectonostratigraphy, age and evolution,” Journal of Asian Earth Sciences, vol. 18, no. 6, pp. 675–690, 2000.

A. M. C. Sengor and U. J. Botum, “The Tethys orogenic system: an introduction,” in Tectonic Evolution of the Tethyan Region, A. M. C. Sengor, Ed., pp. 1–22, Kluwer Academic, Boston, Mass, USA, 1989.

Q. Yan, Z. Wang, S. Liu et al., “Opening of the Tethys in southwest China and its significance to the breakup of East Gondwanaland in late Paleozoic: evidence from SHRIMP U-Pb zircon analyses for the Garze ophiolite block,” Chinese Science Bulletin, vol. 50, no. 3, pp. 256–264, 2005.

P. A. Ziegler, Evolution of Laurussia: A Study in Late Palaeozoic Plate Tectonics, Kluwer Academic, Dordrecht, The Netherlands, 1989.

B. P. Liu, Q. L. Feng, C. Chonglakmani, et al., “Framework of paleotethyan archipelago ocean of western Yunnan and its elongation towards north and south,” Earth Science Frontiers, vol. 9, no. 3, pp. 161–171, 2002.

C. S. Hutchison, Geological Evolution of Southeast Asia, vol. 13 of Oxford Monographs on Geology and Geophysics, Clarendon Press, Oxford, UK, 1989.

H. R. Wu, C. A. Boulter, B. Ke, et al., “The Changning-Menglian suture zone: a segment of the major Cathaysian-Gondwana divide in Southeast Asia,” Tectonophysics, vol. 242, no. 3, pp. 267–280, 1995.

H. Y. Zhang and J. L. Liu, “Plate tectonics and mineralization of the Tethyan ophiolite in the southern Sanjiang and Indo-China peninsular area,” Earth Science, Journal of China University of Geosciences, vol. 36, no. 2, pp. 262–276, 2011 (Chinese).

P. F. Fan, “Accreted terranes and mineral deposits of Indochina,” Journal of Asian Earth Sciences, vol. 18, no. 3, pp. 343–350, 2000.

M. J. Lin, “The volcanic rock sequence and its geological age along the bank of Lancang Jiang, West Yunnan” (Chinese), See: Geology Papers of Qinghai-Tibet Plateau (13)-Rocks in Sanjiang Area, pp. 151–158, 1983

J. Y. Xiong, Y. M. Lin, and S. R. Qin, “A preliminary study on the genesis and the basic characteristics of the Lincang magmatic complex” (Chinese), See: Geology Papers of Qinghai-Tibet Plateau (13)-Rocks in Sanjiang Area, pp. 1–19, 1983

S. Y. Yu, K. Q. Li, Y. P. Shi, and H. H. Zhang, “A study on the granodiorite in the middle part of Lincang granite batholiths,” Yunnan Geology, vol. 22, no. 4, pp. 426–442, 2003.

C. S. Liu, J. C. Zhu, X. S. Xu, X. J. Chu, D. K. Cai, and P. Yang, “Study on the characteristics of Lincang Composite Granite Batholith in West Yunnan,” Yunnan Geology, vol. 8, no. 3-4, pp. 189–212, 1989 (Chinese).

X. L. Li, “Basic characteristics and formation structural environment of Lincang Composite granite batholiths,” Yunnan Geology, vol. 15, no. 1, pp. 1–18, 1996 (Chinese).

J. C. Chen, “Discussion on the age division and the selects of isotopic age determination for granitic rock in Western Yunnan,” Yunnan Geology, vol. 6, no. 2, pp. 101–113, 1987 (Chinese).

X. X. Mo, S. Y. Shen, Q. W. Zhu, et al., Volcanic-Ophiolite and Mineralization of Middle-Southern Part in Sanjiang Area of Southwestern China, Geological Publishing House, Beijing, China, 1998.

D. L. Zhong, Paleo-Tethys Orogenic Zone in Western Yunnan and Western Sichuan, Science Press, Beijing, China, 1998.

A. Socquet and M. Pubellier, “Cenozoic deformation in western Yunnan (China-Myanmar border),” Journal of Asian Earth Sciences, vol. 24, no. 4, pp. 495–515, 2005.

R. G. Park, Foundations of Structural Geology, Chapman & Hall, New York, NY, USA, 2nd edition, 1989.

C. H. Zhang, J. S. Liu, D. L. Liu, and S. Yang, “Geological, geochemical characteristics, age and tectonic setting of Laomaocun small rockbody in South Lancangjiang Zone,” ACTA Mineralogica Sinica, vol. 26, no. 3, pp. 317–324, 2006.

J. C. Chen , “Characteristics of Pb, Sr isotopic compositions in west Yunnan granites: discussion on the age and nature of the basement in west Yunnan,” Scientia Geologica Sinica, vol. 2, pp. 174–183, 1991.

T. M. Dai, B. Q. Zhu, Y. Q. Zhang, Z. P. Pu, Q. F. Zhang, and A. S. Hong, “Collision and thermial history of Indian-Sandaland-Eurasian Plates as implicated by ⁴⁰Ar/³⁹Ar age spectra of granodiorites,” Geochimica, vol. 15, no. 2, pp. 97–107, 1986.

Y. Q. Zhang, Y. W. Xie, and J. W. Wang, “Rb and Sr isotopic studies of granitoids in Tri-river region,” Geochimica, vol. 19, no. 4, pp. 318–326, 1990 (Chinese).

W. Y. Wang, “Rb-Sr isotopic Data,” Yunnan Geology, vol. 3, no. 1, pp. 79–96, 1984 (Chinese).

Yunnan Bureau of Geology and Mineral Resources (YBGM), Geoogical Map of the Jinggu Sheet at a Scale of 1:200, 000, Ministry of Geology and Mineral Resources, Beijing, China, 1983.

Yunnan Bureau of Geology and Mineral Resources (YBGM), Geological Map of the Gengma Sheet at a Scale of 1:200, 000, Ministry of Geology and Mineral Resources, Beijing, China, 1985.

P. Xu, F. Wu, L. Xie, and Y. Yang, “Hf isotopic compositions of the standard zircons for U-Pb dating,” Chinese Science Bulletin, vol. 49, no. 15, pp. 1642–1648, 2004.

S. E. Jackson, N. J. Pearson, W. L. Griffin, and E. A. Belousova, “The application of laser ablation-inductively coupled plasma-mass spectrometry to in situ U-Pb zircon geochronology,” Chemical Geology, vol. 211, no. 1-2, pp. 47–69, 2004.

K. Ludwig, Isoplot/Ex version 2.0: A Geochronological Tool Kit for Microsoft Excel, Geochronology Center Berkeley, Special Publication, 1999.

B. W. Chappell and A. J. R. White, “I- and S-type granites in the lachlan fold belt, Southeast Australia,” in Geology of Granites and their Metallogenetic Relations, X. Keqin and T. Guangchi, Eds., pp. 72–78, Science Press, Bejing, China, 1982.

B. P. Liu, Q. L. Feng, N. Q. Fang, et al., “Tectonic evolution of Paleo-Tethys Poly-island-ocean in Changning-Menglian and Lancangjiang Belts, south-western Yunnan, China,” Earth Science, Journal of China University of Geosciences, vol. 18, no. 5, pp. 529–539, 1993 (Chinese).