Conodont biostratigraphy and biofacies of the Lisburne Group

Abstract

Conodont data from the Lisburne Group are presented in three parts. Part 1 summarizes the thesis work of Andrea P. Krumhardt on the conodont biostratigraphy and biofacies of the Wahoo Limestone in the eastern Sadlerochit Mountains. This is virtually the same report as Krumhardt and others. A more detailed report on the Wahoo Limestone is in the final stages of preparation as a US Geological Survey Professional Paper. The major results of this study include the precise determination of the Mississippian-Pennsylvanian boundary within the lower member of the Wahoo Limestone and establishment of a conodont biostratigraphy for the Pennsylvanian part of the Wahoo that is applicable to northern Alaska. Conodont biofacies are related to depositional environments and compared with carbonate microfacies analyses; both indicate high-energy, chiefly normal-marine conditions in the northern part ANWR. Part 2 describes the conodont zonation used for the middle Carboniferous in northern Alaska and the criteria used for assigning ages. A series of chronostratigraphic diagrams illustrates age variations and correlation of the Lisburne Group in ANWR, at two localities in the central Brooks Range, and in wells in the National Petroleum Reserve in Alaska. Part 3 includes a map showing conodont color alteration indices. Variations inmore » the thermal history of different parts of ANWR are related to the tectonics of the northeastern Brooks Range.« less