Lithostratigraphy, microlithofacies, and conodont biostratigraphy and biofacies of the Wahoo Limestone (Carboniferous), eastern Sadlerochit Mountains, Northeast Brooks Range, Alaska

The Lisburne Group (chiefly Carboniferous) is a widespread succession of platform carbonate rocks that apparently developed along a south-facing passive continental margin in northern Alaska.Marine transgressions onlapped northward across northeast Alaska allowing the Lisburne platform to extend over terrigenous deposits of the Endicott Group and local pre-Mississippian paleotopographic highs.The Wahoo Limestone is the youngest formation of the Lisburne Group in northeasternmost Alaska, ranging from latest Mississippian (latest Chesterian) to Middle Pennsylvanian (at least early Atokan) in age.The Wahoo Limestone was systematically sampled for lithostratigraphy and conodont biostratigraphy and biofacies at a relatively continuous section (about 262 m in thickness) in the eastern Sadlerochit Mountains.Existing Carboniferous conodont zonations could not be readily applied to the study section because most zonal indicators are absent.Species diversity is low for a section that spans at least 10 million years.Twenty-four species, distributed among 14 genera, were identified in 72 productive samples; no new species were distinguished.The following biostratigraphic zones and faunal intervals were recognized: Upper muricatus Subzone (latest Chesterian); noduliferus-primus Zone (earliest Morrowan); minutus Fauna (Morrowan) containing a lower subdivision (lower minutus Fauna of early to middle?Morrowan age); and an Idiognathodus Fauna (Morrowan?to early Atokan).The presence of Idiognathodus incurvusl and Rhachistognathus minutus subspp.above the first occurrence of the foraminifer Pseudostaffella sp. in the uppermost part of the Wahoo Limestone indicates that the youngest beds are early Atokan in age.The Mississippian-Pennsylvanian boundary is