Source provenance

Gill, W.D. (1951). The stratigraphy of the Siwalik Series in the Northern Potwar, Punjab, Pakistan. Quarterly Journal of the Geological Society of London, 107, 375-394.

Cited by 7 units (7 published) · 0 field-level citations · 12 revision notes.

Reviewer-supplied. Foundational stratigraphy of the Siwalik Series in the Northern Potwar (Soan syncline / Jhamat area) - the Potwar type area on which the modern Siwalik chronology (Gill 1951 sensu Johnson et al. 1982) is built. Establishes the lithostratigraphic stages: Kamlial, Lower/Upper Chinji, Nagri, Dhok Pathan (Middle Siwalik) and Tatrot, Pinjor, Boulder Conglomerate (Upper Siwalik), with lithological characters and thicknesses.

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Units citing this source

• Cenozoic Chinji Formation Neogene
  • Lithology: Gill (1951): the Chinji Stage of the Northern Potwar is subdivided into a Lower Chinji Stage (bright-red shales) and an Upper Chinji Stage (brick-red shales with grey sandstone); Gill's stages, originally the palaeontological zones of the Siwalik Series, are the historical basis for the modern Chinji Formation.
  • Lithology: Gill (1951): in the eastern Soan syncline the lowest ~1500 ft (~460 m) of the Chinji Stage develops a sandy 'Kamlial' facies — the Riwat Beds — with ridge-forming sandstones up to 200 ft (~60 m) thick that pass eastward into Chinji beds of type lithology near Riwat village; this local sandy development is matched by a corresponding reduction in the Chinji's normal clay-shale thickness.
• Cenozoic Dhok Pathan Formation Neogene
  • Lithology: Gill (1951): the Dhok Pathan Stage of the Northern Potwar is characterised by variegated shales with sandstone — the upper Middle Siwalik unit above the Nagri Stage.
  • stratigraphicPosition: Gill (1951): at its type locality the Dhok Pathan Stage is soft variegated clay alternating with light-coloured sandstone; near the Indus it includes conglomerate, and eastward a 'Dhok Pathan' facies appears at progressively lower levels, giving a heterochronous (diachronous) boundary with the underlying massive Nagri sandstones.
• Cenozoic Kamlial Formation Neogene
  • Lithology: Gill (1951), Northern Potwar type area: the Kamlial Stage is characterised as hard red and brown ridge-forming sandstone — the basal stage of Gill's Siwalik succession, above the Murree Formation.
  • Lithology: Gill (1951): in the northern Potwar the Kamlial Stage is separated from the underlying Murree Series by its spheroidal weathering, the colour of weathered surfaces and its finer sandstone grain, and throughout the region yields heavy-mineral residues with a flood of tourmaline and a paucity of epidote — the reverse of the epidote-rich, tourmaline-poor Chinji and Murree beds.
• Quaternary Lei Conglomerate Quaternary
  • stratigraphicPosition: Gill (1951): in the Soan area the Lei Conglomerate is a post-Siwalik Pleistocene deposit that rests with strong unconformity on the folded and peneplaned Siwalik succession (Kamlial to Pinjor stages) — the first major unconformity above the otherwise conformable Siwalik pile.
• Cenozoic Nagri Formation Neogene
  • Lithology: Gill (1951): the Nagri Stage of the Northern Potwar is characterised by pepper-coloured (salt-and-pepper) sandstones — the arenaceous middle Siwalik unit above the Chinji Stage.
  • Thickness: Gill (1951): south of the Dhulian oilfield the Nagri Stage is ~4700 ft (~1430 m) thick with more than 65% massive sandstone; near the Indus in the west its upper part carries thick conglomerate beds that pass eastward into massive sandstone, part of a channel-to-flood-plain facies change across the northern Potwar.
• Cenozoic Siwalik Group Neogene
  • Geological significance: Gill (1951), northern Potwar: the Siwalik stages were founded on the vertical predominance of clay or sandstone and only afterwards adopted as vertebrate-faunal zones, which lack sharp definition and are not everywhere fossiliferous, so their boundaries are mapped largely on lithology; the succession also shows marked lateral facies variation across the Potwar — a coarse channel facies along the line of the present Indus grading eastward into flood-plain deposits — which makes correlation by comparative lithology unreliable.
• Quaternary Soan Formation Quaternary
  • Lithology: Gill (1951): the Upper Siwalik of the Northern Potwar (Soan syncline) comprises, in ascending order, the Tatrot Stage (clay, sandstone, conglomerate), the Pinjor Stage (pink silt, sandstone, gravel and conglomerate) and the Boulder Conglomerate Stage (coarse conglomerate and sand) — the historical stages of the Upper Siwalik succession represented in the Soan Formation.
  • Geological significance: Gill (1951): in the Soan syncline the complete Siwalik succession from the Kamlial to the Pinjor Stage (Villafranchian) is free of marked unconformities and is overlain with strong unconformity by the post-Siwalik Pleistocene Lei Conglomerate — differing from de Terra (1936, 1939), who placed the first great unconformity at the base of the Tatrot Stage.