Ordovician-Silurian trace fossils from the Takche Formation, Parahio Valley, Spiti Himalaya, India: biostratigraphic and paleoenvironmental significance

The Ordovician-Silurian trace fossils from the Takche Formation exposed near the Gechang locality, Parahio Valley, Spiti region, Himalaya are described. Following trace fossils were found in the Takche Formation: Arenicolites isp. Aulichnites parkerensis, Archaeonassa fossulata, Catenichnus isp. Cochlichnus isp. Cruziana furcifera, Cruziana goldfussi, Cruziana semiplicata, Chondrites targoni, Chondrites isp. A, Chondrites isp B, Helminthodoichnites isp. Lockeia siliquaria, Laevicyclus mongraensis, Planolites isp. Phycodes circinatus, Phycodes rarus, Phycodes isp. Treptichnus pedum, Thalassinoides isp. and Zoophycos isp. The lowermost part of the Takche Formation yielded significant traces of Cruziana affinity i.e. Cruziana furcifera, Cruziana goldfussi, and Cruziana semiplicata suggesting Tremadocian-Darriwilian age (Lower to Middle Ordovician). The middle part of the Takche Formation is dominated by Zoophycos isp. Chondrites targoni, Chondrites isp. A, and Chondrites isp. B suggests a deeper water offshore setting. The uppermost part yielded Archaeonassa fossulata, Aulichnites parkerensis, Laevicyclus mongraensis, Planolites isp. Helminthoidichnites isp. Phycodes rarus, Phycodes isp. and scratch marks. Overall, the trace fossil assemblages indicate a shallow marine shoreface to offshore depositional setting.