Abstract The Neoproterozoic Windermere Supergroup (WSG) is exposed over an area of 35 000 km 2 in the southern Canadian Cordillera, and consists primarily of deep-marine meta-sedimentary rocks interpreted to have been deposited during rifting and subsequent post-rift thermal relaxation. The main exposures of the WSG occur within thrust panels and structural culminations of the eastern Cordilleran orogen. Within the thick stratigraphic succession ( c. 9 km) are three units of glaciogenic affinity: Toby, Vreeland and Old Fort Point (OFP) formations. The Toby Formation (Fm.) is composed of up to 2500 m of diamictite, interbedded with conglomerate, sandstone, mudstone, carbonate and mafic volcanic rocks. The Vreeland Formation ranges from 350 m to 2000 m in thickness and consists of diamictite, interbedded with mudstone, sandstone and conglomerate. The OFP ranges from 60 to 450 m in thickness and consists of a distinctive threefold stratigraphic package of basal siltstone grading upward into limestone–siltstone rhythmite, organic-rich mudstone and an overlying heterolithic unit of diamictite, breccia, conglomerate, sandstone, siltstone to mudstone and limestone. A locally prominent unconformity marks the base of the OFP upper member. Both the Toby and Vreeland formations represent remobilized glacially derived marine sediments deposited by sediment-gravity flows. Deposition of the Toby Fm. was fault-controlled during an active tectonic phase (rifting), whereas the Vreeland Fm. accumulated during the subsequent quiescent phase (post-rift) with limited structural control. The OFP is interpreted to be a regionally extensive deep-marine post-glacial marker temporally associated with the glaciogenic Vreeland Fm. Although direct geochronological ages for WSG units in southwestern Canada are generally absent, high-precision radiometric ages of underlying and overlying igneous events constrain the relative maximum and minimum timing of deposition from c. 740–728 Ma to c. 569 Ma. At the base of the WSG succession, the Toby Fm. may be as young as c. 685 Ma based on ages obtained from potential stratigraphic correlatives in the USA. There is no direct age constraint for the deposition of the Vreeland Fm.; its minimum timing is based on its stratigraphic relationship with the post-glacial OFP. The middle member of the OFP was precisely dated at 607.8±4.7 Ma using the Re–Os method, placing it in the Ediacaran Period. Published geochemical and stable isotopic data are similarly limited for all three units with only some δ 34 S py values available from one section of the OFP. Recent work has focused on detailed sedimentological and stratigraphic studies of the Toby and OFP formations with future efforts being directed towards integrated geochemical and isotopic research. Additional geochronological constraints are needed to refine palaeogeographical models and strengthen regional correlations with other North American Cordilleran glaciogenic units.

Abstract Unconfined, sand-rich, basin-floor submarine fan deposits have been identified in the Upper Kaza Group of the Windermere Supergroup and are well exposed at the Castle Creek locality, British Columbia, Canada ( Figure 1 ). Regional time slices through the Upper Kaza Group are interpreted to indicate a distal-basin-floor setting for the Castle Creek study area. Correlative strata, becoming more proximal to the continental slope over approximately 300 km (186 mi) in a southeast direction occur at Lake Louise, Alberta ( Figure 1A ). The distribution of facies (Figures 3, 4) has led to a threefold subdivision of the ~600-m (~1968-ft)-thick section which displays an upward decrease in the percentage of sandstones from 67.1% to 60.2% to 58.5%, respectively. This overall decrease in sandstone upwards is associated with a general thinning- and fining-upward trend at the scale of the outcrop. The vertical pattern is interpreted to reflect a change from an axial zone of sandstone deposition to an off-axis area with less sandstone and more mudstone or alternatively, an overall backstepping of the basin-floor-fan system. The lower Upper Kaza is characterized by amalgamated medium- to coarse-grained sandstone turbidites with scoured contacts. Lateral changes in sandstone to mudstone and character of outcrop gamma-ray profiles are interpreted as a change from a channelized lobe-interior to lobe-margin (lobe-fringe to interlobe). The presence of significant bypass facies (mudstone breccias and medium-scale cross-stratified sandstone) and scour surfaces differentiate the middle Upper Kaza from the lower Upper Kaza and mark a change to sediment bypass and scouring