Ice-flow history and drift prospecting in the Committee Bay belt, central Nunavut: results from the Targeted Geoscience Initiative

Abstract

Mapping of ice-flow indicators in the Committee Bay supracrustal belt (NTS 56 K, 56 J/9 to /16, 56-O/1 to /8, and 56 P) provides new evidence for a complicated ice-movement chronology during the Late Wisconsinan. Three main phases of ice movement have been identified at the regional scale. The oldest is northerly and is found throughout most of the area. This was followed early in the deglaciation sequence by northeastward flow in the eastern part of the area and northwesterly flow in the western part. Finally, there is a north-northwesterly flow south of the Chantrey moraines, associated with ice flow from the Keewatin Ice Divide. Results from drift-prospecting studies indicate that till geochemistry reflects a clear northerly direction of glacial transport. Most of the known gold showings are recognized in the gold-grain counts and/or the gold values in the till matrix, but at least two previously unknown, potentially gold-rich domains have been identified.

Genesis of hummocks in glaciofluvial corridors near the Keewatin Ice Divide, Canada

“…The 8 kyr margin inferred for phase 3 roughly corresponds to the position of the Chantrey Moraine (Dyke 2004). Phase 1 (LGM), reported by Little (2001) and McMartin et al (2003), was not detected in the Walker Lake map area. The approximate location of the Keewatin Ice Divide is generalized from Aylsworth & Shilts (1989) and Dyke (1984).…”

“…The last glacial ice movement history for the area is well documented (Little 2001; Little et al 2002; Ozyer & Hicock 2002; McMartin et al 2003; Utting 2004a) with multiple ice‐movement phases recognized within the region (Fig. 1).…”

Evidence from Keewatin (Central Nunavut) for Paleo-Ice Divide Migration*

“…The Dubawnt Lake ice stream was operating in the Thelon River valley (Stokes and Clark, 2003), extending back to areas close to the ice divide. After 8.2 ka BP, the ice stream shut down, the ice front continued to retreat easterly, and the ice divide probably began to migrate back to the northwest as shown on Figure 12 at Phase F. North of Wager Bay, the ice flow became more northerly, perpendicular to an ice front that is oriented into a general east-west configuration (Phase III, McMartin et al, 2003b). South of the divide, the southeastward flow commenced to become convergent as a result of marine drawdown into a rapidly retreating calving front in Hudson Bay (8-7.7 ka BP, Dyke, 2004).…”

“…The northern extent of the southerly flows lies immediately north of Schultz Lake, east of Tehek Lake and across Wager Bay (Cunningham and Shilts, 1977;McMartin and Dredge, 2005). Pervasive, opposite, early northward erosional forms and glacial dispersal have been observed west of Committee Bay to the north (Phase I, McMartin et al, 2003b). If these opposite flows were contemporaneous, we believe a dispersal centre or major ice divide may have been positioned in Keewatin, between the study area and Committee Bay, and across Wager Bay (Fig.…”

“…12), perhaps forming a lobe in Queen Maud Golf at 8.5 ka BP (Dyke, 2004). A northeastward ice flow into paleo-Committee Bay (Phase II, McMartin et al, 2003b) may have been operating during this phase as the ice front retreated and formed a calving bay in that area (9-8.5 ka BP, Dyke, 2004).…”