@article{RehmanTanakaKobayashietal.2014,
  author    = {Rehman, Hafiz Ur and Tanaka, Ryoji and Kobayashi, Katsura and Tsujimori, Tatsuki and Nakamura, Eizo and Yamamoto, Hiroshi and Khan, Tahseenullah and Kaneko, Yoshiyuki},
  title     = {Oxygen isotopes in Indian Plate eclogites (Kaghan Valley, Pakistan): Negative delta O-18 values from a high latitude protolith reset by Himalayan metamorphism},
  series = {Lithos : an international journal of mineralogy, petrology, and geochemistry},
  volume    = {208},
  journal   = {Lithos : an international journal of mineralogy, petrology, and geochemistry},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0024-4937},
  doi       = {10.1016/j.lithos.2014.09.007},
  pages     = {471 -- 483},
  year      = {2014},
  abstract  = {Oxygen isotope compositions are reported for the first time for the Himalayan metabasites of the Kaghan Valley, Pakistan in this study. The highest metamorphic grades are recorded in the north of the valley, near the India-Asia collision boundary, in the form of high-pressure (HP: Group I) and ultrahigh-pressure (UHP: Group II) eclogites. The rocks show a step-wise decrease in grade from the UHP to HP eclogites and amphibolites. The protoliths of these metabasites were the Permian Panjal Trap basalts (ca. 267 +/- 2.4 Ma), which were emplaced along the northern margin of India when it was part of Gondwana. After the break-up of Gondwana, India drifted northward, subducted beneath Asia and underwent UHP metamorphism during the Eocene (ca. 45 +/- 1.2 Ma). At the regional scale, amphibolites, Group I and II eclogites yielded delta O-18 values of +5.84 and +5.91 parts per thousand, +1.66 to +424 parts per thousand, and -2.25 to +0.76 parts per thousand, respectively, relative to VSMOW. On a more local scale, within a single eclogite body, the delta O-18 values were the lowest (-2.25 to-1.44\%.) in the central, the best preserved (least retrograded) parts, and show a systematic increase outward into more retrograded rocks, reaching up to +0.12 parts per thousand. These values are significantly lower than the typical mantle values for basalts of + 5.7 +/- 0.3 parts per thousand. The unusually low or negative delta O-18 values in Group II eclogites potentially resulted from hydrothermal alteration of the protoliths by interactions with meteoric water when the Indian plate was at southern high latitudes (similar to 60 degrees S). The stepwise increase in delta O-18 values, among different eclogite bodies in general and at single outcrop-scales in particular, reflects differing degrees of resetting of the oxygen isotope compositions during exhumation-related retrogression. (C) 2014 Elsevier B.V. All rights reserved.},
  language  = {en}
}
@article{RehmanLeeChungetal.2016,
  author    = {Rehman, Hafiz Ur and Lee, Hao-Yang and Chung, Sun-Lin and Khan, Tahseenullah and Yamamoto, Hiroshi O´Brien},
  title     = {Source and mode of the Permian Panjal Trap magmatism: Evidence from zircon U-Pb and Hf isotopes and trace element data from the Himalayan ultrahigh-pressure rocks},
  series = {Lithos : an international journal of mineralogy, petrology, and geochemistry},
  volume    = {260},
  journal   = {Lithos : an international journal of mineralogy, petrology, and geochemistry},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0024-4937},
  doi       = {10.1016/j.lithos.2016.06.001},
  pages     = {286 -- 299},
  year      = {2016},
  abstract  = {We present an integrated study of LA-ICP-MS U-Pb age, Hf isotopes, and trace element geochemistry of zircons from the Himalayan eclogites (mafic rocks) and their host gneisses (felsic rocks) from the Kaghan Valley in Pakistan in order to understand the source and mode of their magmatic protoliths and the effect of metamorphism. Zircons from the so-called Group I (high-pressure) eclogites yielded U-Pb mean ages of 259 +/- 10 Ma (MSWD = 0.74), whereas those of Group II (ultrahigh-pressure) eclogites yielded 48 3 Ma (MSWD = 0.71). In felsic gneisses the central or core domains of zircons yielded ages similar to those from Group I edogites but zircon overgrowth domains yielded 47 +/- 1 Ma (MSWD = 1.9). Trace element data suggest a magmatic origin for Group I-derived (having Th/U ratios: >0.5) and metamorphic origin for Group II -derived (Th/U < 0.07) zircons, respectively. Zircon Hf isotope data, obtained from the same dated spots, show positive initial Hf-176/Hf-177 isotopic ratios referred to as "epsilon(Hf)(t)" of around +10 in Group I eclogites; +7 in Group II eclogites; and +8 in felsic gneisses zircons, respectively, thus indicate a juvenile mantle source for the protolith rocks (Panjal Traps) with almost no contribution from the ancient crustal material. The similar epsilon(Hf)(t) values, identical protolith ages and trace element compositions of zircons in felsic (granites or rhyolites) and mafic (basalt and dolerite) rocks attest to a bimodal magmatism accounting for the Panjal Traps during the Permian. Later, during India-Asia collision in Eocene times, both the felsic and mafic lithologies were subducted to mantle-depths (>90 km; coesite-stable) and experienced ultrahigh-pressure metamorphism before their final exhumation. (C) 2016 Elsevier B.V. All rights reserved.},
  language  = {en}
}