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xii Swedish expeditions followed. In January 1894, a small caravan led by the famous Swedish explorer Sven Hedin left Tashkent for crossing of the Pamirs to reach Kashgar in China. Sven Hedin was trained in physical geography and on his way he made lotmeasurements in the Karakul lake in the north-eastern Pamirs. Lake Karakul is divided into two basins and Hedin discriminated a deeper western (ca. 230 m) and a shallower eastern basin (ca. 50 m). As the Lake Karakul region was one of our main working areas it was exciting to follow Sven Hedin’s footsteps. Towards the end of the 19th century white areas on the maps of Central Asia gradually disappeared as more and more geographic and topographic information was acquired. Sven Hedin again took part in an excursion to the Pamirs in 1928. It was the German- Russian Alai-Pamir expedition (Fig. 2) which produced one of the first scientific compilations about the Pamirs including many geological aspects (Nöth 1932). But the Pamirs remained a wild region with many little known valleys and peaks. During the first research expeditions of the Soviet Academy of Science to the Pamirs between 1928 and 1933 mountaineering exploration began. Tourist expeditions to the Pamirs were first undertaken in the 1950s and since then the Pamirs have been the most popular outdoor mountain region of the former Soviet Union. Unfortunately, today the Pamirs tend to be a more and more remote region again, due to its geopolitical position. In the rear of this, it is even more exciting to elucidate the Pamirs Palaeozoic to Tertiary evolution.
The amalgamation of the Pamirs and their subsequent evolution in the far field of the India-Asia collision Abstract The geodynamic understanding of the Pamir mountains in Central Asia has been hitherto rather fragmentary, despite its importance as one of the linking segments recording the history of the Tethys ocean between southeast Asia and the Alps. A new model for the Pamirs accounts in particular for the structural correlation with the neighbouring Tibetan and Afghan units. Radiometric age dating (U/Pb, Rb/Sr and Ar/Ar) and geochemical provenance analyses of W-E oriented magmatic belts and associated rock assemblages in the southern Tien Shan and eastern Pamirs elucidate the principal geodynamic phases of the region. The events can be comprehended following a N-S transect through the region: (1) During the early and middle Palaeozoic, an active continental margin existed at the northern margin of the Palaeotethys, striking nearly parallel to the present-day Tien Shan orogen. In the middle and late Palaeozoic, marginal basins were closed and several terranes accreted. Early Permian (~277 Ma), calc-alkaline granitoids from the southern Tien Shan exemplify this development. They correlate with intrusions of the Garm-Turkestan-Alay zone west of the Tien Shan, which is attributed to the northward directed closure of the South Gissar ocean. This closure likely coincided with the disappearance of the South Tien Shan ocean, another marginal basin east of the determined transect. Thereby, the Baysunta and Garm terranes and the Tarim block were accreted. (2) Southwardly contiguous to the South Tien Shan and the intramontane Alay valley, the northern Pamirs expose metavolcanic rocks (Altyndara section), ~370-330 Ma of age, that represent a possible western extension of the north Kunlun arc of western Tibet. Consecutive late Palaeozoic to Triassic subduction of the Sonpan-Ganze ocean created the southern Kunlun of western Tibet, an equivalent of which is conjectured to exist in the northern Pamirs. (3) Permo-Triassic volcaniclastic rocks form the Karakul-Mazar accretionary complex in the southern part of the northern Pamirs, which resulted from northward oriented subduction of the Sonpan-Ganze ocean underneath the southern Kunlun arc (see above) and southward oriented subduction along the Tanymas suture underneath the area now represented by the northern edge of the Central Pamirs. This cryptic southern suture correlates with the Tibetan Jinsha suture and the Central Pamirs corresponds to the Qiangtang block. The post-tectonic massive Lake Karakul batholith was emplaced into the accretionary units of the northern Pamirs at ~227 Ma, roughly coinciding with similar granitoids of northwest Tibet (~227-199 Ma). Comparable Permo-Triassic volcaniclastic successions and Triassic plutonites are reported from the western Badakshan, western Hindu Kush, and Feroz Koh of Afghanistan. (4) Medium to high grade metamorphites of the Sonpan-Ganze ocean floor and its mainly Triassic mélange compose basement domes in the Central Pamirs, which have been exhumed in the Tertiary. In the Qiangtang block of Tibet, basement domes of analogous composition have been exhumed already in the late Mesozoic. It is 1
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 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 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
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52 associations in Afghanistan is f
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54 Kara Kunlun or Mazar accretionar
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56 Early Jurassic low-angle normal
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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
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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
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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
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XIV Tab. A9 U/Pb isotopic ratios fr
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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
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XXX
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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
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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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