Weird Scenes Inside the Gold Mine; Finding Debris from the Avak Impact

By

A.C. Banet (Bureau of Land Management)

The Geologic Materials Center (GMC) in Eagle River is the Alaska repository for cores and cuttings from numerous petroleum and mineral exploration activities. The GMC is a valuable storehouse of hard data without which so much logging and geophysical data are merely measurements. In addition to petroleum and exploration data, the GMC repository also provides insights geological questions. The Avak impact is the northernmost impact feature of the known Cretaceous seaway impacts. Core and cuttings from the Cape Simpson area show allochthonous lithologies, including coarse and angular fragments of sandstone and argillite that are similar in appearance to the debris described from the Avak well core. These sandstone and argillite fragments are suspended in a matrix of soft gray clay. Well correlations and paleo data show this unit is the upper Cretaceous Seabee Shale (shale of the Colville Group). If the debris found in the Simpson area proves to correlate to the Avak impact, its level within the Seabee Formation could provide a more precise age estimate than previous workers. 

AAPG Search and Discovery Article #90008©2002 AAPG Pacific Section/SPE Western Region Joint Conference of Geoscientists and Petroleum Engineers, Anchorage, Alaska, May 18–23, 2002.