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74 cooling rates of all samples. Samples P2 and P5, the Late Cretaceous intrusions of the northernmost South Pamirs, were difficult to model, due to their low number of confined track length (
amphibole, white mica, and biotite as well as K/Ar dating of sericite (Appendix A, Tab. A3, A4, A5). These dating methods were determined on samples from the Muzkol and Sares domes (Fig. 4.1): (1) Rb/Sr whole rock-muscovite ages of basement rocks, e.g. biotite schists and gneisses, were determined on two samples from the southern side of the Sares dome. Sample 96A5i yielded 37.1±0.4 Ma and sample A96A5k 30.0±1.2 Ma. The sample 96Ak3d from the northern side of the Muzkol dome obtained an age of 68.0±7.7 Ma. As the error is very high, the date will not be included into the discussion or conclusion. (2) Several intrusions and dykes of likely Tertiary age were probed in the Muzkol and Sares domes. Sample P17, an undeformed aplite dyke that cuts high-grade biotite gneiss in the Muzkol dome is already described in chap. 3: the sample contains inherited zircons with spot ages in the range of 561 to 424 Ma, which are attributed to characterise the Qiangtang basement. Conventional U/Pb zircon dating points to an upper intercept age of 539±5 Ma with assumed Pb-loss at 44±22 Ma. Such a crystallisation/Recent Pb-loss model infers Tertiary disturbance of the U/Pb system, even so no Tertiary rims could be detected with SHRIMP analyses. Nevertheless, it was suggested that the dike was emplaced in the Tertiary (Schwab et al. in press). Another Tertiary intrusion (P15) into the Muzkol dome and a dyke of the Sares dome (96A6b) yielded conventional U/Pb zircon upper intercept ages of 540±4 Ma and 570±230 Ma, respectively. The lower intercept age is around 31±2 Ma in case of sample P15, and around 17±8 Ma for sample 96A6b. The U/Pb data are included in Appendix A, Tab. A7. (3) Rb/Sr whole rock-muscovite dating of sample L96A11a, a pegmatitic dyke crosscutting basement units of the Sares dome, gave an age of 13.7±0.1 Ma (see Appendix A, Tab. A5). (4) Ar/Ar amphibole, muscovite, and biotite ages of the Muzkol and Sares domes were obtained from basalts, basement, and intrusive rocks. The data are summarised in Appendix A, Tab. A3. The metamorphic mineral ages are in the range of 28 to 14 Ma. Tertiary basalts crosscut the Muzkol and Sares domes and extruded in an extensional setting as indicated by structural analyses and preliminary geochemical classifications (see Appendix A, Tab. A2). The basalts yield Ar/Ar whole rock ages of about 20 Ma. (5) Sandstones from Tertiary sediments from the Murgab profile (Fig. 4.4) show anchi- to greenschist facies overprint. Five samples of metamorphic grown sericite were dated by the K/Ar method (see Appendix A, Tab. A4). The ages range from 14 Ma in the north of the section to 33 Ma further to the south. 4.3 Discussion South Tien Shan Fission track ages of Tertiary sediments from the southernmost Tien Shan confirm the Palaeozoic and Mesozoic history of the Tien Shan as suggested in chapter 3: the basement of the Tien Shan is composed of different terranes which were originally sutured together during two collisions in Late Devonian-Early Carboniferous and Late 75
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Institut für Geowissenschaften (IF
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Key words: Tien Shan, Pamirs, Tibet
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* Nr. 22 MESCHEDE, M. (1994): Tecto
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* Nr. 55 REINECKER, J. (2000): Stre
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The amalgamation of the Pamirs and
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Wer aber je auf Asiens Erdboden sch
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viii (1971). Black lines with arrow
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x sample locations and age distribu
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xii Swedish expeditions followed. I
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2 postulated that the Safed Khers a
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4 Zusammenfassung Die paläozoische
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6 (d) Oberkreide Spaltspurenalter w
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8 deformation propagate from the pl
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10 source terrains, changes in the
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12 Geochemisches Zentrallabor, Univ
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14 mean UO+/U+ and Pb+/U+ value. Si
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16 apatites and zircons were counte
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18 number of simulation runs and th
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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
Page 86 and 87: 62 Palaeogene volcanic rocks of cen
Page 88: 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: Thermal modelling The results of th
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
Page 112 and 113: 88 6 References Allègre C.J., Cout
Page 114 and 115: 90 House, scale 1:2 000 000. Chen F
Page 116 and 117: 92 Karakorum (Sinkiang, China); the
Page 118 and 119: 94 Hurford A.J. and Hammerschmidt K
Page 120 and 121: 96 without double spiking. Geochimi
Page 122 and 123: 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
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XXVIII
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XXX
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XXXII
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XXXIV
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XXXVI Tab. C5 continued Sample grai
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XXXVIII Tab. C5 continued Sample gr
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XL Tab. C5 continued Sample grain-n
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XLII Tab. C5 continued Sample grain
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XLIV
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XLVI Tab. C6 Zircon fission track a
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XLVIII
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LII
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LIV Tab. C7 Apatite and zircon fiss
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