Chhidru Formation

Merged duplicate unit "Chidru Formation" (chidru-formation) into this record. Sources, provinces and any missing fields were carried over; the old name is retained as a synonym.

Malkani, M.S. & Mahmood, Z. (2017)

Gee (1989): the Chhidru Formation was the 'Upper Productus Limestone' of earlier usage — the uppermost formation of the Late Permian Zaluch Group (Amb–Wargal–Chhidru).

Gee, E.R. (edited by Gee, D.G.) (1989)

Waterhouse (2010): the Chhidru Formation straddles the Wuchiapingian–Changhsingian boundary. Its lower and middle beds (Kufri Member) are late Wuchiapingian — the conodont Clarkina longicuspidata occurs very low (near the basal Changhsingian per Wardlaw & Mei 1999) and the ammonoid Cyclolobus is typical of late Wuchiapingian faunas — while the higher beds (Ganjaroh 'bivalve beds' and the capping Khisor Sandstone Member) are provisionally basal-to-mid Changhsingian, the Khisor palynomorphs (Cancellosa Zone: Triplexisporites playfordii, Playfordiaspora cancellosa) indicating a mid-Changhsingian age. Correlation with the Chhidru is what yields an unusually high four biozones in the Changhsingian Stage; a carbon-isotope decline accelerates to ~−2‰ at the top of the formation.

Waterhouse, J.B. (2010)

Waterhouse (2010): three members are recognised — the Kufri Member (lower–middle beds), the Ganjaroh Member (Waagen's 1891 'bivalve beds'), and the Khisor Sandstone Member (the topmost 'white sandstone', shallow subtidal–intertidal with freshwater influence). About 140 brachiopod species have been described from the formation.

Waterhouse, J.B. (2010)

Kazmi & Jan (1997): the Chhidru Formation (type Chhidru Nala) is 75–85 m of basal dark sandy shale passing up to calcareous/sandy sandstone and limestone, capped by a distinctive white sandstone (≤5 m); Late Permian (most probably Late Dzhulfian), the uppermost Permian being missing. Conformable/transitional on the Wargal and overlain by the Mianwali Formation across a palaeontologically-indicated para-unconformity; abundant brachiopods and ammonoids (Cyclolobus).

Kazmi, A.H. & Jan, M.Q. (1997)

Hemphill & Kidwai (1973, USGS PP 716-B), Paniala area: the Chhidru Formation is mostly grey/brown friable calcareous micaceous sandstone with thin argillaceous limestone, carrying Bellerophon and abundant productid brachiopods; ~130 ft south of Paniala, disconformably overlain by the Triassic Mianwali Formation (the old 'Bellerophon / Upper Productus beds').

Hemphill, W.R. & Kidwai, A.H. (1973)

Ali et al. (2021): measured Chhidru thicknesses vary across the western Salt Range — Zaluch Nala 58.4 m, Zaluch Gorge 63.63 m, Chhidru Nala 81.81 m (compiled after Mertmann 2003; Jan & Stephenson; Hussain et al.). The dataset's ~90 m (60-120 m) is retained as a regional representative; the Chhidru Nala type section is ~82 m.

Ali, S.K., Janjuhah, H.T., Shahzad, S.M., Kontakiotis, G., Saleem, M.H., Khan, U., Zarkogiannis, S.D., Makri, P. & Antonarakou, A. (2021)

Ali et al. (2021): the top of the Chhidru Formation marks the Permian-Triassic boundary — a paraconformity of undetermined magnitude beneath the Triassic Mianwali Formation; the lower contact with the Wargal Limestone is conformable (the Wargal/Chhidru boundary approximates the Wuchiapingian/Changhsingian boundary). Uppermost formation of the Tethyan Zaluch Group.

Ali, S.K., Janjuhah, H.T., Shahzad, S.M., Kontakiotis, G., Saleem, M.H., Khan, U., Zarkogiannis, S.D., Makri, P. & Antonarakou, A. (2021)

Ali et al. (2021), facies analysis at Zaluch Gorge (western Salt Range): the Late Permian Chhidru Formation comprises three lithofacies - a limestone facies (CF1), a limestone-with-clay-interbeds facies (CF2) and a sandy-limestone facies (CF3) - and five carbonate microfacies spanning mudstone-biomicrite (MF-1) to packstone-biosparite (MF-5). The assemblage indicates a shallow-marine, middle- to outer-shelf setting deposited within a highstand systems tract (HST). Adds a facies/sequence-stratigraphic characterization of the depositional environment.

Ali, S.K., Janjuhah, H.T., Shahzad, S.M., Kontakiotis, G., Saleem, M.H., Khan, U., Zarkogiannis, S.D., Makri, P. & Antonarakou, A. (2021)

Ali et al. (2021), full text: the Chhidru Formation was deposited on a middle-to-inner shelf in a shallow-marine (subtidal-intertidal) setting, at the top of a highstand systems tract (HST). Three lithofacies (CF1 limestone, CF2 limestone with clay interbeds, CF3 sandy limestone) and five microfacies (MF1 mudstone-biomicrite to MF5 packstone-biosparite) were recognised at Zaluch Gorge.

Ali, S.K., Janjuhah, H.T., Shahzad, S.M., Kontakiotis, G., Saleem, M.H., Khan, U., Zarkogiannis, S.D., Makri, P. & Antonarakou, A. (2021)

Craig et al. (2018): the uppermost-Permian Chhidru Formation is listed among the potential Permian source rocks of the Upper Indus Basin (with the Dandot and Sardhai formations; Quadri & Quadri 1996; Wandrey et al. 2004).

Craig, J., Hakhoo, N., Bhat, G.M., Hafiz, M., Khan, M.R., Misra, R., Pandita, S.K., Raina, B.K., Thurow, J., Thusu, B., Ahmed, W. & Khullar, S. (2018)