--> ABSTRACT: Paleocurrents Beside an Obliquely Convergent Plate Boundary (Sulaiman Foldbelt, Southwestern Himalayas, West-Central Pakistan), by Abdul Waheed, Neil A. Wells, Nazir Ahmad, and Kenneth D. Tabbutt; #91030 (2010)

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Paleocurrents Beside an Obliquely Convergent Plate Boundary (Sulaiman Foldbelt, Southwestern Himalayas, West-Central Pakistan)

Abdul Waheed, Neil A. Wells, Nazir Ahmad, Kenneth D. Tabbutt

Cretaceous to Holocene paleocurrents at the north and south ends of the Sulaiman Range show flow trending westward, then variably eastward, southward, and finally eastward. Pre-orogenic Cretaceous shelf sandstones show dispersal to the southwest, north-northwest, and west-southwest off the craton. However, Paleocene marine sandstones in the south spread east-southeast, and early Eocene deltaic sandstones in the north spread southeast and north. These sandstones indicate slope reversal of the Cretaceous shelf.

Post-Oligocene fluvial molasse shows mostly southward drainage. The 3,852 m northern molasse section comprises a lower 2,378 m of claystones and upwardly fining sandstones that are thought to represent meandering rivers, and an upper 1,474 m dominated by conglomerates, representing gravelly braided rivers. Lower paleocurrents were to the southeast, but variable, whereas upper paleocurrents were more uniform and gradually shifted from southeast to east. The 3,146-m southern section comprised (1) a basal 1,160 m claystone and sandstone sequence (meandering streams with very diverse flow directions, overall to the southwest), (2) a middle 1,703 m sequence dominated by pebbly sandstone with very large bedforms (big sandy braided rivers with less diverse flow to the southwest), and (3) an pper 283 m conglomeratic sequence (gravelly braided streams that still flow uniformly west-southwest). Early flow obliquely toward the Sulaiman Range suggests no uplift of the range until the onset of modern eastward drainage and the influx of conglomerates, which occurred 700 m lower in the north. The northern and southern sections otherwise show similar histories of fluvial sedimentation.

AAPG Search and Discovery Article #91030©1988 AAPG Annual Convention, Houston, Texas, 20-23 March 1988.