Furongian conodonts from the Machari Formation in the Gokgeum section, Yeongwol, Korea

Abstract

This is a conodont biostratigraphic study on the Machari Formation in the Gokgeum section, exposed nearby Mt. Orosan, Hutan-ri, west Yeongwol-gun, Korea. Three biostratigraphic intervals are recognized by euconodont taxa in the Furongian part of the Gokgeum section: i.e., Unnamed, Proconodontus muelleri, and Eoconodontus notchpeakensis zones in ascending order. The Unnamed zone herein is equivalent to the previous “Barren Interzone”, the Proconodontus muelleri Zone is also equivalent to the previous Proconodontus muelleri-Cambrooistodus cambricus Zone, and the Eoconodontus notchpeakensis Zone is a new, uppermost one. Therefore, there are four conodont zones of the Machari Formation known hitherto; i.e., late Middle Cambrian Westergaardodina matsushitai Zone and three Furongian zones including Unnamed zone, Proconodontus muelleri Zone and Eoconodontus notchpeakensis Zone in ascending order. These Machari conodont biozones are correlated with conodont biozonal frameworks in western USA, Canada, Argentina, North and South China, Australia and Hwajeol Formation in the Duwibong area, Korea.