Buffalo Head Hills kimberlite field

It is located about 400 km (250 mi) north of the city of Edmonton in the Buffalo Head Hills of northern Alberta.

[3] Deep beneath the BHH kimberlite field lies a 2.0 to 2.4 billion year old Precambrian craton called the Buffalo Head terrane, which has no exposure at surface.

Because of this thick cover of Quaternary sediments and lack of bedrock outcrops, the BHH kimberlite pipes were discovered primarily through interpretation of geophysical data from aeromagnetic and gravity surveys, followed by drilling programs.

Marine microfossils in mudstones that are interbedded with some of the kimberlite deposits are consistent with the Late Cretaceous age.

[3] They represent maar-style volcanoes which have a vertical-walled volcanic crater of explosive origin, surrounded by a low rim of ejecta and filled with water.

These represent a series of discrete kimberlite eruption events separated by quiescent periods during which the muds were deposited.