Seismic velocities from the Kohistan volcanic arc, north Pakistan

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doi: 10.1144/gsjgs.146.6.0971
Authors:Chroston, P. N.; Simmons, G.
Author Affiliations:Primary:
Univ. East Anglia, Sch. Environ. Sci., Norwich, United Kingdom
Other:
Mass. Inst. Technol., United States
Volume Title:Journal of the Geological Society of London
Source:Journal of the Geological Society of London, 146(6), p.971-979. Publisher: Geological Society of London, London, United Kingdom. ISSN: 0016-7649
Publication Date:1989
Note:In English. 44 refs.; illus. incl. 1 table, geol. sketch map
Summary:The rocks bounded by the Main Mantle Thrust and the Northern Suture in N Pakistan constitute an exhumed section through a Cretaceous volcanic arc. A reconstructed velocity section through the arc shows a distinct 'upper crust' comprising granitic- dioritic intrusions, metasediments and volcanic rocks with a P- wave velocity of 6.2-6.4 km/s. Beneath, the 'lower crust' of amphibolites and pyroxene granulite has a velocity mainly approx 6.4-6.7 km/s, though the garnet granulites extend to 7.8 km/s. The more mature arc with a higher proportion of granitic rocks would show a slightly lower upper crustal velocity than the younger arc. Velocity inversions might be expected with a thermal gradient of as little as 10-15 degrees C/km, depending on the pore P. [R.A.H.]
Subjects:Cretaceous; Crust; Mesozoic; Seismology; Velocity structure; Asia; Indian Peninsula; Pakistan; Chalt Volcanics; Chilas Complex; Jijal Complex; Kamila Amphibolites; Kohistan volcanic arc; Northern Pakistan
Abstract Numbers:90M/2375
Record ID:1990013281
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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