Regional differences in Mississippian spore assemblages

Abstract

Differences in composition of contemporaneous Mississippian spore floras have been observed and the causes of the variation are discussed. The differences in composition are more readily apparent in the spore assemblages of Osagean to Springeran age and they have been interpreted to reflect a regional differentiation into three floral provinces. The three floral provinces are characterized by distinctive spore associations which have been termed the Grandispora suite, the Monilospora suite and the Kazakhstan suite. Spore assemblages of a similar composition lie within broad latitudinal belts parallel to the palaeoequator of Mississippian times. For this reason, it is believed that the distribution of the spore floras is climatically controlled.Evidence will be presented to show that a regional differentiation was already in existence in the Kinderhookian. Two spore suites have been distinguished and these have been called the Vallatisporites and Lophozonotriletes suites. These spore floras are less well known and, consequently, the limits of the floral provinces cannot be accurately defined. They do, however, reflect to some degree the pattern of regional variation observed in the younger Mississippian spore assemblages.