Source provenance
Shah, M.T. & Shervais, J.W. (1999). The Dir-Utror metavolcanic sequence, Kohistan arc terrane, northern Pakistan. Journal of Asian Earth Sciences, 17(4), 459-475.
Cited by 1 unit (1 published) · 0 field-level citations · 3 revision notes.
Petrology and arc setting of the Dir-Utror metavolcanic sequence; primary source for the Dir Group volcanics in the Kohistan arc.
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Units citing this source
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- stratigraphicPosition: Shah & Shervais (1999): in the NW Kohistan arc the Dir Group comprises, from the base, the Baraul Banda slate (calcareous siltstone/slate — Fletcher's 1985 'tuffite' — up to ~4 km thick, with early Eocene microfossils), the Dir-Utror metavolcanic series, and the Panakot meta-arkose.
- Lithology: Shah & Shervais (1999): the Dir-Utror volcanic series is dominated by porphyritic basaltic-andesite and andesite with subordinate basalt, high-MgO basalt, dacite and rhyolite, metamorphosed to greenschist facies (chlorite-epidote-albite-actinolite); its calc-alkaline whole-rock trend and LILE-enriched, Nb-P-Ti-depleted trace-element patterns are typical of subduction-related arc magmatism.
- Age: Shah & Shervais (1999): the Dir-Utror volcanics represent a Paleocene-Eocene 'successor arc' built on the accreted Mesozoic Kohistan arc; 40Ar-39Ar hornblende ages of 58-61 Ma (Treloar et al. 1989) and early Eocene microfossils in the underlying Baraul Banda slate bracket its age, close to the ~50-55 Ma initial closure of the Neo-Tethys.