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8 deformation propagate from the plate margins to the interior of the continent? � What is the Cenozoic to recent thermotectonic response of the crust to the ongoing contraction across the Tien Shan and Pamir regions? Based on the acquired data, their interpretation in relation to the evolution of the Pamirs, this thesis comprises the following main chapters: � Crustal assemblage of the Pamirs: age and origin of magmatic belts from the southern Tien Shan to the eastern Pamirs (chapter 3). � Cenozoic exhumation history of the South Tien Shan and eastern Pamirs (chapter 4) Finally, this study results in a redefined age zonation and amalgamation history of the Pamirs and provides the first comprehensive research project about the Tertiary low-T evolution post-dating the India-Asia collision.
2 Sample preparation and analytical techniques 2.1 Sampling strategy In this study, a combination of petrology, geochemistry and geochronology was used to identify and characterise the timing, correlation in space and time, and the tectonic environment of magmatic arcs in the southernmost Tien Shan and northeastern Pamirs. Petrological and geochemical data were used for standard classification of magmatic rocks and to estimate their origin and the tectonic environment in which they were placed. It was further aimed to estimate by isotopic data like �Nd-values, if there was any changing influence of lower and upper crustal compositions to melting processes. U/Pb geochronology was applied to obtain the first reliable crystallisation and metamorphic dates and to constrain whether new crustal material was generated or older crustal components were reworked inferred by inherited components. Rb/Sr and Ar/Ar data were used to determine metamorphic and cooling ages. These medium- T ages support the U/Pb ages or serve as minimum estimates for crystallisation ages when U/Pb ages were not determined. To constrain the latest stage of mountain building the fission track thermochronology as a lowtemperaturegeochronological method was applied. With the aid of fission track analyses and in combination with the medium-T geochronology the long term cooling history and erosional behaviour of the mountain range was determined. Furthermore, zircon and apatite fission track ages and the fission track length study in apatites was used to constrain the temperature history of sedimentary basins. Peaks in the age spectrum of sediments defined the input of different 9
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 26 and 27: 2 postulated that the Safed Khers a
Page 28 and 29: 4 Zusammenfassung Die paläozoische
Page 30 and 31: 6 (d) Oberkreide Spaltspurenalter w
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
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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
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Southern Tien Shan One Permian gran
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Thermal modelling The results of th
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amphibole, white mica, and biotite
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the zircon PAZ. The apparent apatit
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elt likely operated as an out-of-se
Page 105:
ages from gneissic rocks within the
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84 south to 18 Ma in the north; the
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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
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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
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100 Zamoruyev A., 1995a. Neotectoni
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102 Ann. Rev. of Earth and Planetar
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104 this work, especially all membe
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II Appendix A Tab. A1 Sample descri
Page 134 and 135:
IV Tab. A2 continued Pamir frontal
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VI Tab. A2 continued Tertiary exten
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VIII Tab. A3 continued Sample Miner
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X Tab. A6 Rb/Sr and Sm/Nd isotopic
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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
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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
Page 178 and 179:
XLVIII
Page 182 and 183:
LII
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LIV Tab. C7 Apatite and zircon fiss
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