Radiolarian fauna found from Tieshidas Group in East Kunlun

The Tieshidas Group in Qimantag, a branch of the East Kunlun Mountains, was classically considered the Caledonian basement, and classified into Middle -Upper Ordovician, Upper Ordovician or simply Lower Paleozoic. The radiolar ian fauna was found, for the first time, from a chert block in the Tieshida s Group at Yaziquandaban (Pass) north to Ayakum Lake. They are Astroentacti nia? mirousi Gourmelon, As. ct biaciculata Nazarov, Archocyrtium of. diduct um Deflandre, Ar. aff, diductum Deflandre, Deflandrellium? sp., Entactinia vulgaris Won, En. of. additiva Foreman, En.? sp., Entactinosphaera palimbol a Foreman, Pylentonema? sp., Triaenosphaera sp. and Tr.? sp. The geological age of this radiolarian fauna is Early Carboniferous, Evidently, the class ical interpretation about the age of Tieshidas Group needs to be checked an d modified. Except the Ordovician proved with the formerly discovered fossi ls, it also includes, at least, Lower Carboniferous rocks. There was still an oceanic basin at Qimantag during Early Carboniferous (and even a long ge ological time after then). Qimantag is not a Caledonian fold belt, and the Tieshidas Group is not the Caledonian basement.