Walker Island Member

Unit Name: Walker Island Member
Unit Type: Lithostratigraphic
Rank: Member
Status: Formal
Usage: Currently in use
Age Interval: Early Cretaceous (145.5 - 99.6 ma)
Age Justification: Stratigraphic relationships; the Walker Island Member is bracketed by a Barremian age below and an Aptian age above.
Province/Territory: Arctic Offshore; Northwest Territories; Nunavut; Yukon Territory

Originator: Embry, 1985.

Type Locality:

The type section is located in the Sun Skybattle C-15 well, where the member is 140 m thick.

Distribution:

Occurs over most of the Sverdrup Basin, and reaches maximum thickness over eastern Ellef Ringnes Island.

Locality Data:

WELL 300C157720105000; SKYBATTLE BAY C-15. Thickness(m): Minimum 20, Maximum 500. Interval(m): From 924, To 1064.

Lithology:

"The Walker Island Member is composed predominantly of very fine- to coarse-grained sandstone with interbeds of medium- to dark-grey, carbonaceous siltstone, shale and minor coal. Coarsening-upwards cycles up to 30 m thick occur in the lower and uppermost portions of the member, with fining-upward cycles an associated coal occurring in the mid-portions of the member. Individual sandstone units are up to 25 m thick, and the shale-siltstone units are usually less than 10 m thick. Sandstones capping the coarsening-upward cycles are commonly horizontally bedded to ripple crosslaminated. Trough and planar crossbeds occur in sandstone units that fine upward." (Embry, 1985)

Relationship:

A member of the Isachsen Formation. The Walker Island Member conformably overlies the Rondon Member, and is conformably overlain by the Christopher Formation.

History:

Named after Edmund Walker Island, south of Lougheed Island.

Other Citations:

Embry, A.F., 1985. Stratigraphic subdivision of the Isachsen and Christopher formations (Lower Cretaceous), Arctic Islands; Geological Survey of Canada, Paper 85-1B, pp. 239-246.

References:

Embry, A.F., 1985. Stratigraphic subdivision of the Isachsen and Christopher formations (Lower Cretaceous), Arctic Islands; Geological Survey of Canada, Paper 85-1B, pp. 239-246.

Embry, A.F., 1985b, New stratigraphic units, Middle Jurassic to lowermost Cretaceous succession, Arctic Islands. Geological Survey of Canada, Paper 85-1B, pp. 269.

Source: GEOLOGICAL SURVEY OF CANADA, CALGARY
Contributor: G.E. McCune
Entry Reviewed: No
Name Set: Lithostratigraphic Lexicon
LastChange: 09 Feb 2009