Fluvial sedimentary architecture at the foothills of the Himalayas, Middle-Late Miocene Kamlial Formation, Salt Range, Pakistan

A detailed sedimentological study of the middle-late Miocene Kamlial Formation was carried out from three stratigraphically important sections namely Khajula, Khokarbala and Chakkhushi, Salt Range, Pakistan.The thickness of the Kamlial Formation is from 55m to 120m and predominantly composed of dark-grey to greenish-grey sandstone interbedded with dark-red to maroon coloured siltstone/mudstone and subordinate intraformational conglomerates. Sandstone is predominantly composed of monocrystalline with rare polycrystalline; feldspar is mainly orthoclase, plagioclase and minor microcline. Rock fragments are mainly contributed by sedimentary and metamorphic and minor igneous sources. A variety of sedimentary structures were recorded including bedding and lamination, massive bedding, planar and trough cross-bedding, ripple marks, mud cracks, channels, calcretes, bioturbation and rootlet beds. A total of ten lithofacies and five architectural elements in the Kamlial Formation have been recognized. The Kamlial Formation shows cyclic deposition of various faciesin a fining upward succession. Thickness of individual cycles increases towards east. Palaeocurrent data of both trough and planar cross-bedded units of the Kamlial Formation were measured and analyzed indicating south-east palaeoflow direction from north-west source area. The present study shows that the Kamlial Formation is fluvial in origin and deposited by a braided river. The lithofacies of the Kamlial Formation is mainly controlled by Himalayan orogeny in source area.

Keywords:

Carbonatite , Allanite , Britholite , REE , Iran