Megafaunal Zones in Alberta Mississippian and Permian: ABSTRACT

Abstract

Twelve faunal zones are proposed for the thick sequence of beds lying between the top of the Devonian and the base of the Mesozoic in Alberta. Of these, eleven lie within the range of time represented by the Mississippian of the type region, the remaining one is of Permian age. No beds of undoubted Pennsylvanian age have been seen in the southern Alberta Rocky Mountains or in the adjacent subsurface. The lower four zones are grouped under a single time stratigraphic term for which the name Banffian is proposed; this includes strata equivalent to the Kinderhook and probably part of the Osage of the standard Mississippia Valley section. It corresponds with the Banff formation at the type section at Banff. The remaining Mississippian zones, of which the youngest is the Spirifer leidyi zone of late Chesterian age, are grouped together under the term Rundlian. Strata assigned to the Rundlian include the whole of the Rundle group. The lithological junction of the Banff and Rundle is not necessarily at the close of the Banffian. The proposed zones, together with their relationship to the lithological sequence, are shown in the table. The rock succession is neither abundantly nor uniformly fossiliferous and there are some major unfossiliferous intervals which materially hinder accurate correlation, especially in the early Rundlian. Faunal assemblages representing the Kinderhook, Osage, Meramec, and Chester of the Mississippi Valley undoubtedly occur in Alberta, but there are some gaps, notably the apparent absence of the older Chester faunas. It is not known yet to what extent these gaps are due to inhibited migration, facies control, or stratal non-sequence. Rocky Mountain Formation, Permian Table The proposed zonal scheme is put forward as an interim working hypothesis, based on presently available information. It will be subject to modification and revision as further paleontological data become available. End_of_Article - Last_Page 421------------