The Geomorphology of Stewart Island, New Zealand

Evidence of glacial activity at Mt Allen, southern Stewart Island, New Zealand

“…The 70 m wide separation between this ridge and the bedrock forming the eastern face of Mt Allen, and the presence of subrounded pebbles and boulders within the sediment that forms the ridge, implies that it did not develop as a result of a landslide as has previously been suggested (Williams 1936), or as a talus fan at the base of the steep face to the west. The lack of an associated cirque upslope from the southern ridge suggests some similarities with protalus ramparts rather than a moraine loop.…”

“…The southern ridge had previously been noted by Williams (1936) who suggested that it formed as a result of a landslide rather than glacial activity. Willett (1950) and Watters et al (1968) have subsequently cited the southern ridge as evidence of glacial activity at Mt Allen despite the apparent contradiction with Williams' (1936) original description. To the authors' knowledge the northern ridge remains undescribed.…”

“…The low altitude of the ELA suggests that glacial activity may have occurred on other relatively high peaks on Stewart Island, that were above the altitude of Pleistocene snowlines. To date, moraine deposits have been recognised only in the vicinity of Mt Anglem (Williams 1936;Willett 1950;Watters et al 1968) and Mt Allen. The mean altitude of the cirques at Mt Anglem implies an ELA at c. 700-730 m, 100 m higher than the ELA at Mt Allen.…”

“…1) (Williams 1936;Willett 1950;Watters et al 1968), where two small lakes occupy cirques dammed by ridges of moraine. These lakes are at altitudes of 610 ± 10 and 690 + 10 m above sea level, respectively, indicating that the small glaciers on Mt Anglem extended over altitudes between 980 and 610 m. Williams (1936) suggested that the "glacial cycle did not develop beyond the neve stage in the southern highlands" including the area around Mt Allen (Fig. 1).…”

Glaciation of mt allen, stewart island (rakiura): the southern margin of lgm glaciation in new zealand

“…Cockayne (1909) acknowledged that glaciers had eroded the basin on the southern flank of Mt Anglem, and suggested glaciation may have been much more extensive than a cirque glaciation. In contrast, Williams (1936) concluded glaciation was restricted to Mt Anglem in the north, and indicated that the southern debris ridge on Mt Allen (Fig. 2) was of landslide origin, a view at variance with that of Willett (1950), Watters et al (1968) and Allibone and Wilson (1997).…”