Toward a better understanding of northern Alaska’s petroleum systems: Deconstructing the Barrow arch

Abstract

For more than 60 yr, the term “Barrow arch” has been used to describe a regional structural high beneath northern Alaska and the Beaufort and Chukchi Seas that is of chief importance to the area’s petroleum systems. However, there are multiple interpretations of what, precisely, constitutes the Barrow arch. For example, most, but not all, interpretations invoke the arch as a basement feature. Other interpretations refer to a Barrow arch that existed in different forms at widely variant times, from the early Paleozoic to the present, and although many authors refer to the feature as “composite” or “complex,” the arch is normally drawn on maps as a single lineation. Numerous meanings of the term Barrow arch have been conflated in the literature resulting in some contradictory usages; this paper is an attempt to clarify the nomenclature. Six primary usages of the term Barrow arch are identified in this paper. These are the (1) basement high, (2) ancestral highlands, (3) rift margin, (4) Lower Cretaceous unconformity antiform, (5) Brookian sill, and (6) dip reversal usages. These usages are deconstructed herein, and other names of more exacting definitions are introduced. These newly defined terms are the “basement arch,” “Ellesmerian highlands,” “rift shoulders,” “northern Alaska anticlinorium,” and “Colville rim.” “Basement subcrop areas” are introduced as regions where basement rocks were eroded to a peneplain beneath unconformities; these help to isolate the various northern Alaskan rift shoulders. It is recommended that the term Barrow arch be discarded. The northern Alaska anticlinorium is the most significant newly defined feature for northern Alaska’s petroleum systems.