Open File Report 1996-09

Open File Report 1996-09

OFR 1996-09

The Provenance of Diamond Indicator Minerals in Bedrock of the Hinton Area, Alberta Foothills

Author(s) Langenberg, C.W. Skupinski, A. Date 1996-01-01

Bedrock sampling confirmed that diamond indicator minerals are present in Cretaceous and Tertiary rocks of the Hinton area, Alberta. A major find is the presence of olivines (including diamond inclusion olivines) in these sediments. Another find is that sediments, which are older than Maastrichtian, contain diamond indicator minerals in the Cadomin area. This might indicate that there were 2 periods of ultramafic, and possibly kimberlite or lamproite, intrusions: one in the Maastrichtian around 70 Million years ago and an older one possibly in the Aptian around 110 Million years ago.

our anomalous areas including the Entrance, Cadomin, Ruby Creek and Coal Valley areas can be delineated. These areas could contain ultramafic diatremes. Based on bedrock samples, the Entrance and Cadomin areas rank highest in terms of diamond exploration potential.

A study of thin sections from the bedrock samples show that chromite, ilmenite and garnet can be recognized and micro-probed. A layer with 20 ilmenite grains may provide additional support for a local source of the grains.

Paleocurrent analysis shows preferred directions between azimuths N010� and N160� East for Late cretaceous and Tertiary sediments, with a few deviating directions towards N325� East. These directions may reflect local current directions during deposition that can be used to find local source areas and possibly low ultramafic diatremes.