DISTRIBUTION OF SILURIAN AND LOWER DEVONIAN VERTEBRATE MICROREMAINS AND CONODONTS IN THE BAILLIE-HAMILTON AND CORNWALLIS ISLAND SECTIONS, CANADIAN ARCTIC

Abstract

We studied the distribution of vertebrate microremains and conodonts, and measured carbon isotope values in several sections on Baillie-Hamilton and Cornwallis islands from the Upper Llandovery, Silurian, up to Lower Devonian. Thelodont genera Loganellia, Shielia, Goniporus, Katoporodus, Nikolivia, Canonia, and Turinia, and seven new thelodont taxa were recognized. Four (three?) genera of anaspids and three chondrichthyans were found for the first time. Acanthodians include Gomphonchus sandelensis, Nostolepis striata. N. gracilis, Poracanthodes punctatus, and P. porosus types of scales. Ten vertebrate assemblages were established. Conodonts, ostracodes, and carbon isotope values were used for age determination. Conodonts (Pterospathodus cf. amorphognathoides, Pt. pennatus procerus. Apsidognathus lobatus. A. aff. ruginosus, Aspelundia fluegeli, etc.) indicate the Telychian age for the lower part of the studied Cape Phillips Formation. The Wenlock-Ludlow boundary was recognized in the Baillie-Hamilton 2 section. Ozarkodina cf. eurekaensis, appearing in the uppermost part of the Barlow Inlet Formation in the eastern Cornwallis, allows correlation of these strata with the Lochkovian. Four carbon isotope positive peaks known from Wenlock, Ludlow, Pridoli, and Silurian-Devonian transition in the Baltic, the Central Urals, and Australia, are well represented in the Canadian Arctic.