Publication Name: The Canning Basin, W.A.
Authors: Gary D. Powis
Date Published: December 1984
Number of Pages: 21
Reference Type: Book Section
Abstract:
Six palynological assemblages from Namurian to Early Permian strata are briefly described together with their relative stratigraphic positions. They include a new Westphalian assemblage, the Diatomozonotriletes birkheadensis Assemblage whose nominate species, Diatomozonotriletes birkheadensis sp. nov. is formally defined .. A major microfloristic change in the early Stephanian occurs above this new zone, at the base of Stage 1. The pre-Stephanian assemblages are typical of pre-glacial environments and have elements characteristic of the European Late Carboniferous. Stage 1 and younger assemblages typify the glacial and post-glacial palynofloras of the Gondwanan floristic realm.Because of the current problems involved in the subsurface correlation of the two loosely defined Late arboniferous rock units of the Canning Basin viz. the upper part of the Anderson Formation and the overlying
Grant Group, it is proposed that a reference datum be used to approximate the base of the Grant Group and therefore, the top of the Anderson Formation. This datum equates with channelling events recognised on
seismic sections, and the climatic and depositional changes which occurred at the base of strata containing
the Stage 1 assemblage. It is proposed that all strata containing the immediately pre-glacial assemblages be
contained within the Anderson Formation. This will alleviate the inconsistencies which presently exist in the
informal stratigraphic nomenclature for the section of pre-glacial strata known to exist above the presently
defined top of the Anderson Formation in Grant Range No. 1 and the postulated base of the Grant Group.