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2 postulated that the Safed Khers area of Afghanistan hosts similar basement domes, and the Band-e Bayan and Farah Rod zones of that country correlate with the Mesozoic Central Pamirs and Qiangtang cover sequences. (5) Calc-alkaline granitoids (~190-150 Ma) cut the southern Central and northern Southeast Pamirs. They intruded into the eastern Pshart oceanic basin-arc sequence and formed the Rushan Pshart arc. The Farah Rod zone of Afghanistan likely represent the western continuation of this setting and granitoids of the southern Qiangtang block of Tibet (~170-160 Ma) epitomize its eastern prolongation. These successions and intrusives of the Rushan Pshart zone record the closure of probably several small, laterally arranged transpressive basins reaching into the Bangong-Nujiang zone between the Qiangtang and Lhasa blocks in Tibet. These basins were finally consumed by Mid-Jurassic times. (6) Zircons of Late Miocene xenoliths and of Cretaceous plutons from the central and southern Pamirs suggest a prolonged magamtic history of the region comprising four main phases: Cambro-Ordovician (~575-410 Ma); Triassic (~250-200 Ma), related to subduction along the Jinsha suture and/or Triassic rifting; Jurassic (~200-150 Ma), related to subduction along the Rushan Pshart suture; and Cretaceous. The Cretaceous activity may comprise peaks at ~120 Ma and ~80 Ma, reflecting arc activity prior to accretion of the Karakorum block probably along the Tirich Mir fault and flat-slab subduction along the Shyok suture north of the Kohistan-Ladakh arc respectively. The above outlined accretion history is supported by fission track ages of detrital apatites and zircons depicting four major phases of tectonic activity: (a) Age populations of ~370 Ma from Tertiary sedimentary basins of the northern Pamirs and northern Central Pamirs are interpreted to be related to the first, northern Kunlun arc stage. (b) A Permo-Triassic cluster ranging from ~266 to 242 Ma was detected in all studied regions from the southern Tien Shan to the eastern Pamirs. These ages argue for Triassic rifting and/or Triassic southward subduction along the Jinsha suture. (c) Jurassic age populations from 170-145 Ma occur in Tertiary sedimentary rocks of the South Tien Shan, Kunlun, southern Qiangtang, and Rushan Pshart zone. They are attributed to the Rushan Pshart arc formation and Rushan Pshart basin closure in Mid- Jurassic, which entailed the collision of the Central Pamirs and southeast Pamirs. The coincident collision of the Qiangtang and Lhasa blocks caused for instance Mid- Jurassic compressive deformation in the Kunlun mountains. (d) Late Cretaceous fission track ages were determined on apatites of Tertiary intramontane basin sediments from the South Tien Shan and on zircons from intrusive rocks of the northern and southern Central Pamirs. These ages may reflect limited exhumation induced by underthrusting of the southeastern Pamirs beneath the southern margin of the Central Pamirs and by intracontinental subduction of the Karakul-Mazar and Jinsha lithosphere underneath the northern margin of the Central Pamirs. This compression was probably triggered by flat-slab subduction along the Shyok suture, between the Karakoum and Kohistan-Ladakh terranes.
The protracted accretion history came to a close with the final collision between India and Eurasia ~55 Ma ago, establishing the Pamirs into an intracontinental position. Deformation did not propagate continuously from south to north, but it might have instead concentrated in rheologically weakened zones, like the Central Pamirs. There, intracontinental subduction along the Jinsha suture and Rushan Pshart zone may have favoured deformation, generation of melt, and the emplacement of the prominent Muzkol and Sares domes. Their exhumation between 25 to 15 Ma seemed to have heated southerly contiguous Tertiary intramontane basins. Coevally, the northern margin of the Karakul-Mazar belt was exhumed along the right-lateral transpressional Markansu fault. Apatite fission track analyses across the Karakul lake batholith gave ages from 56 to 18 Ma with a younging towards the north. Early Miocene exhumation was followed by eastward lateral extrusion and uplift along large (Karakorum, Markansu) and conjugated (southern Tien Shan margin, frontal Pamirs, southern Central Pamirs margin) strike-slip faults, thus compensating for continuous N-S compression between India and Asia; these zones are active at least since 11-10 Ma. 3
Page 1: Institut für Geowissenschaften (IF
Page 4 and 5: Key words: Tien Shan, Pamirs, Tibet
Page 6 and 7: * Nr. 22 MESCHEDE, M. (1994): Tecto
Page 8 and 9: * Nr. 55 REINECKER, J. (2000): Stre
Page 13 and 14: The amalgamation of the Pamirs and
Page 15: Wer aber je auf Asiens Erdboden sch
Page 20 and 21: viii (1971). Black lines with arrow
Page 22 and 23: x sample locations and age distribu
Page 24 and 25: xii Swedish expeditions followed. I
Page 28 and 29: 4 Zusammenfassung Die paläozoische
Page 30 and 31: 6 (d) Oberkreide Spaltspurenalter w
Page 32 and 33: 8 deformation propagate from the pl
Page 34 and 35: 10 source terrains, changes in the
Page 36 and 37: 12 Geochemisches Zentrallabor, Univ
Page 38 and 39: 14 mean UO+/U+ and Pb+/U+ value. Si
Page 40 and 41: 16 apatites and zircons were counte
Page 42 and 43: 18 number of simulation runs and th
Page 45 and 46: Two Palaeozoic sutures divide the C
Page 47 and 48: igneous and sedimentary rock sequen
Page 49 and 50: Triassic and the formation of an is
Page 51 and 52: 27 Lake Karakul The Lake Karakul ar
Page 53: 3.3.2 Major and trace elements Majo
Page 56 and 57: 32 of 26-40 for samples P2, P5, and
Page 58 and 59: 34 some of the zircons suffered Pb
Page 60 and 61: 36 fractions are situated close to
Page 65: 3.4.2 Rb/Sr dating The Rb/Sr minera
Page 69 and 70: 45 The Cretaceous plutons show mode
Page 72 and 73: 48 Thompson et al. (1984), who see
Page 74 and 75: 50 granites and have Sm-Nd model ag
Page 76 and 77:
52 associations in Afghanistan is f
Page 78 and 79:
54 Kara Kunlun or Mazar accretionar
Page 80 and 81:
56 Early Jurassic low-angle normal
Page 82 and 83:
58 Coward et al. (1988) pointed out
Page 84 and 85:
60 oceanic crust for the consumptio
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62 Palaeogene volcanic rocks of cen
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64 3.7 Conclusions Based on new own
Page 91 and 92:
4 Cenozoic exhumation history of th
Page 93 and 94:
Southern Tien Shan One Permian gran
Page 97 and 98:
Thermal modelling The results of th
Page 99 and 100:
amphibole, white mica, and biotite
Page 101 and 102:
the zircon PAZ. The apparent apatit
Page 103 and 104:
elt likely operated as an out-of-se
Page 105:
ages from gneissic rocks within the
Page 108 and 109:
84 south to 18 Ma in the north; the
Page 110 and 111:
86 Cretaceous plutons that intrude
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88 6 References Allègre C.J., Cout
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90 House, scale 1:2 000 000. Chen F
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92 Karakorum (Sinkiang, China); the
Page 118 and 119:
94 Hurford A.J. and Hammerschmidt K
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96 without double spiking. Geochimi
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98 Geological Society of America, 2
Page 124 and 125:
100 Zamoruyev A., 1995a. Neotectoni
Page 126 and 127:
102 Ann. Rev. of Earth and Planetar
Page 128:
104 this work, especially all membe
Page 132 and 133:
II Appendix A Tab. A1 Sample descri
Page 134 and 135:
IV Tab. A2 continued Pamir frontal
Page 136 and 137:
VI Tab. A2 continued Tertiary exten
Page 138 and 139:
VIII Tab. A3 continued Sample Miner
Page 140 and 141:
X Tab. A6 Rb/Sr and Sm/Nd isotopic
Page 142 and 143:
XII Tab. A7 continued Apparent ages
Page 144 and 145:
XIV Tab. A9 U/Pb isotopic ratios fr
Page 146 and 147:
XVI Tab. A9 continued 207 Pb/ 206 P
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XVIII Tab. A9 continued 207 Pb/ 206
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XX Appendix B Plate B1 Cathodolumin
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XXII Plate B3 Cathodoluminescence i
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XXIV Plate B5 Cathodoluminescence i
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XXVI Tab. C2 Determination of the
Page 158 and 159:
XXVIII
Page 160 and 161:
XXX
Page 162 and 163:
XXXII
Page 164 and 165:
XXXIV
Page 166 and 167:
XXXVI Tab. C5 continued Sample grai
Page 168 and 169:
XXXVIII Tab. C5 continued Sample gr
Page 170 and 171:
XL Tab. C5 continued Sample grain-n
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XLII Tab. C5 continued Sample grain
Page 174 and 175:
XLIV
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XLVI Tab. C6 Zircon fission track a
Page 178 and 179:
XLVIII
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LII
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LIV Tab. C7 Apatite and zircon fiss
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