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28 (1) P17, an undeformed aplite dike, crops out along the northern margin of the Muzkol dome and cuts high-grade, locally migmatitic basement biotite-gneiss and Early Cretaceous non-metamorphic red beds. (2) A series of Late Cretaceous, probably Early Tertiary intrusive bodies crops out along the northern margin of the Muzkol dome. One sample (A96S1b) is a subalkaline to alkaline subvolcanic latite-andesite with actinolithe, clinopyroxene, plagioclase, Kfeldspar and relatively little quartz. (3) In the easternmost part of the Muzkol dome several small gabbro-bodies intrude basement biotite-gneisses. Sample 96M9a is a leucogabbro with a considerable amount of alkali-feldspar with perthitic segregation and primary magmatic plagioclase, which is replaced by epidote and a second generation of plagioclase. Epidote is overgrown by vesuvianite (idocrase) and both minerals are graphically intergrown with plagioclase. Accessory minerals are titanite and high amounts of zircon. Titanite contains some grains of rutile. Green biotite and amphibole are sometimes intergrown, and biotite encloses apatite. In summary, the leucogabbro represents a highly fractionated late-magmatic intrusion, metamorphosed under amphibolite facies or probably under high-pressure conditions (rutile). (4) Sample 96M18a is from a fine-grained clastic layer within massive dolomites of likely Silurian age cropping out along the northern margin of the Muzkol and Sares domes. (5) At the junction of the Pshart- and Murgab valleys a further granite intrusion is exposed. Sample L96M25a is a biotite-granite with chloritised biotite, sericitised Kfeldspar, microcline and weakly deformed quartz, intruding a possible Permo-Triassic meta-volcaniclastic sequence. (6) Further to the west in the Pshart valley, a granitoid pebble (96P4e) from a likely Miocene intramontane basin conglomerate is determined as a slightly deformed twomica granite. (7) At the northern side of the Pshart valley, a ?Carboniferous chlorite-muscovitestaurolite-garnet schist (A96M18h) was sampled at the base of the Permo-Triassic sequence. Along the northern margin of the Aksu valley occurs a W-E to NW-SE striking belt of granites: (8) sample L96A9 is a biotite granite intruding a possible Early to Late Palaeozoic sequence west of the Sares dome, (9) sample P7 is a white mica granite, and (10) M96A7 a two-mica granite that intruded into likely Palaeozoic sequence or Jurassic rocks. (11) A very small intrusive granitoid was sampled in the south-eastern part of the Aksu valley (96A10b) that was determined to be a biotite granite. Northernmost South Pamirs In the northern part of the south-east Pamirs, a series of granites and granodiorites intrude Late Palaeozoic to Jurassic rocks in blocks rimmed by Cenozoic dextral transpressional faults. These blocks were thrust northward onto the Rushan Pshart zone, north-west of Murgab. Two granodioritic intrusions (P2 and P5) were sampled in the Murgab valley, where they cut a passive margin sequence of Late Palaeozoic to Jurassic age.
3.3.2 Major and trace elements Major and trace element concentrations of all samples are compiled in Appendix A, Tab. A2. Plutonic rocks of the South Tien Shan (STS) were identified as monzogranites, and the subvolcanic rocks as granodiorites (Fig. 3.5a). Metavolcanic rocks of the northern Pamirs (Altyndara valley) have basaltic to rhyolitic compositions, batholiths of the Lake Karakul area are monzogranites and granodiorites, whereas most plutons of the Central Pamirs (CP) and the Rushan Pshart Zone (RPZ) are monzogranites. Further sampled rock types in the Central Pamirs are a leucogabbro (96M9a) and a latiteandesite (A96S1b). Igneous rocks from the STS belong to sub-alkaline respectively high-K calc-alkaline, mainly peraluminous I-types (Fig. 3.5b, h), and only the northernmost sampled rocks TS1 and TS2 are transitional to S-type series. The latter two samples imply a higher degree of crustal contamination as indicated by the lack of hornblende, more K-feldspar megacrysts, and the higher A/CNK ratio and SiO 2 content (Fig. 3.5b). All rock samples are interpreted as volcanic arc related (Fig. 3.5f-i), but with probably more fractionated rock types to the northeast. Chondrite-normalised rare earth element (REE) patterns of the South Tien Shan samples (Fig. 3.6a) show strong fractionation of the LREE (La N/Sm N = 4-6) and only a weak negative Eu-anomaly (Eu* was determined from interpolation of REE patterns between Sm and Tb). The HREE are most fractionated in samples TS12a,b and less fractionated in the subvolcanic rock samples TS18a, TS20a. The North Pamirs metavolcanic rocks from the Altyndara valley have low- to medium-K character (Fig. 3.5c) and are metaluminous (Fig. 3.5b). Although all samples show a clearly calc-alkaline trend (Fig. 3.5d), the basalt samples plot into the MORB field (Fig. 3.5e). The rock-types with MORB affinity were formed in an oceanic or early arc setting, whereas all other samples represent normal volcanic arc rocks (Fig. 3.5f). This is also reflected in the chondrite-normalised REE patterns (Fig. 3.6b): the oceanic or early-arc volcanic rocks show flat, typical MORB patterns; normal arc samples and samples with increasing SiO 2-contents show steeper LREE fractionation patterns. Only the samples AD2a and AD6b display a distinctly negative Eu-anomaly. The Lake Karakul batholiths are peraluminous, mainly S-type monzogranites (Fig. 3.5b), and have high K-contents. In context with their petrological features, they are classified as post-tectonic granitoids with an arc to late-/post-collisional geochemical signature (Fig. 3.5f-i). The rocks show a consistent strong fractionation from La to Sm and the magnitude of the negative Eu-anomaly (Eu/Eu* = 0.62-0.74) increases with increasing SiO 2-contents (Fig. 3.6b). The leucogabbro 96M9a (dark grey circle) intrudes schists and gneisses in the eastern part of the Muzkol dome. It has low K-contents (Fig. 3.5c), a metaluminous character (Fig. 3.5b), and seems to be secondarily enriched in SiO 2. The REE pattern is generally enriched with La N/Lu N = 20.6 and shows a positive Eu-anomaly (Eu/Eu* = 1.2), probably due to plagioclase enrichment. The Triassic/Jurassic monzogranites (dark grey circles) are heterogeneous in their major- and trace element contents. Sample L96M25a is a metaluminous I-type monzogranite with high K-contents like the other samples of this group (Fig. 3.5a-c). The rock is interpreted as volcanic arc related (Fig. 3.5f-i) with an overall depletion of HREEs and a weakly negative Eu-anomaly (Fig. 3.6c). The two Jurassic samples L96A9 29
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 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: 27 Lake Karakul The Lake Karakul ar
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 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
Page 112 and 113:
88 6 References Allègre C.J., Cout
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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
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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
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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
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VI Tab. A2 continued Tertiary exten
Page 138 and 139:
VIII Tab. A3 continued Sample Miner
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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
Page 148 and 149:
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
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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
Page 176 and 177:
XLVI Tab. C6 Zircon fission track a
Page 178 and 179:
XLVIII
Page 182 and 183:
LII
Page 184:
LIV Tab. C7 Apatite and zircon fiss
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