Abstract:
The Permo-Triassic successions of Salt Range, Pakistan provide one of the rare opportunity to study the change in global environments, near the major extinction event of geologic history. One of the sections, Nammal Gorge, is located approximately 30km northeast of Mianwali District, Punjab, Pakistan along Mianwali-Musakhel road. Specimens of Permian Brachiopods (Silicified) have been studied from Wargal Formation (Upper part) and the Chhidru Formation. Palaeontological study resulted in the identification of the following 14 genera: Ombonia, Gypospirifer (Spirifer), Meekella, Cartorhium, Neospirifer, Rugatia, Nudauris, Neophricadothyris, Waagenoconcha, Linoproductus, Cleiothyridina, Composita, Derbyia and Marginifera. In addition, the following 15 species were recognized: Ombonia invecta, Gypospirifer infraplicus (Spirifer marcoui), Meekella calathica, Cartorhium vidriense, Neospirifer neali, Rugatia mckeei, Nudauris diabloensis, Neophricadothyris catatona, Waagenoconcha abichi, Linoproductus semisulcatus, Linoproductus angustus, Cleiothyridina pilularis, Composita crassa, Derbyia pannucia and Marginifera opima. Based on the studies and research of the above fauna, three-biostratigraphic zones: have been established as: (A) Neospirifer sp. indicating Kazanian age, (B) Waagenoconcha abichi indicating Early Dzhulfian age and (C) Derbyia pannucia-Marginifera opima indicating Late Dzhulfian age. The Permian Brachiopod shells from the Nammal Gorge section are divisible into two silicified types: (1) shells with siliceous coatings and (2) shells with a thick, single layer of silica. Two distinct palaeoenvironments have been interpreted on the bases of the above-mentioned Brachiopod fauna: (1) outer sublittoral environments for the upper part of the Wargal Formation and (2) inner sublittoral environment for the Chhidru Formation.
Page(s):
469-484
DOI:
DOI not available
Published:
Journal: Proceedings SPE-PAPG Annual Technical Conference, Volume: 0, Issue: 0, Year: 2004