Stratigraphy and paleomagnetism of Late Pliocene and Pleistocene sedimentsin the Wellsch Valley and Swift Current Creek areas, southwestern Saskatchewan, Canada

The Late Pliocene and Pleistocene are represented in southern Saskatchewan by sequences of preglacial, glacial, and nonglacial deposits. These have be en studied in surface exposures and bore cores and have been subdivided and correlated on the basis of their lithologies. In this study, new observati ons of magnetic polarity are presented. They reveal a lower preglacial sequ ence (Empress Group) with reversed polarity, and an upper normally magnetiz ed sequence which contains glacial deposits of pre-Illinoian, Illinoian, an d Wisconsinan age and which are correlative with the Saskatoon and Sutherla nd groups of central Saskatchewan. The reversed preglacial sequence is refe rred to the Matuyama Zone (Late Pliocene to Early Pleistocene: 2.58-0.78 Ma ) and the normal glacial sequence to the Brunhes Zone (Middle to Late Pleis tocene and Holocene: 0.78 Ma to present). In southern Saskatchewan there is no evidence of glaciation during the Late Pliocene and Early Pleistocene ( Matuyama Chron) which is in marked contrast with parts of the Cordilleran r egion of western Canada where glaciations occur throughout this time.