GLACIOLOGY REPORT

Much of the work of the two earlier Expeditions, to the ice-free Wright and Victoria Valleys was concerned with observations of the glacio-geomorphology. From the re-location of remnant glacially-cut benches and the distribution of moraines of different ages in the two valleys, history of the retreat of the ice has been inferred.

The glaciological work of the present Expedition has been mainly a continuation and extension of these observations. The glaciers which formerly filled the Wright and Victoria Valleys were of a different type from these which previously filled the tributary valleys in the area north of the Koettlitz Glacier; in the Wright and Victoria Valleys the glaciers were carrying ice from the west of the Victoria Land ranges, through the valleys to McMurdo Sound, while in the Koettlitz area most of the small glaciers were supplied completely from local névé fields. The Koettlitz Glacier itself is fed from a larger nevé which however is comparatively small compared to, say, the Skelton Glacier which cuts the Koettlitz off from the Antarctic ice plateau.

From the pattern of moraines and glacially-cut benches throughout the area, several phases in the valley glaciers and of the Koettlitz Glacier can be inferred:

1.	At some early stage, perhaps of maximum Antarctic glaciation, all the area, with the exception of the divide of the Royal Society Range and a few nunataks to the west, was ice covered. Accordance of peak levels on the spurs along the front of the southern Royal Society Range suggests older glacially cut surfaces of a later period. There is reason to suspect that the peaks of the northern Koettlitz (Salmon District) area likewise show such an accordance of peak level. The spurs of the dividing ridges of the Koettlitz alpine glaciers also show vestigal evidence of glacial benching. These accordant height areas have since been severely fretted by alpine (valley) glaciation. In the area surveyed peaks have been ice sculpture to “horns” and the page 9 alpine valleys cut to almost present level: those in the south being above present sea level, those in the north below.
2.	Later or even contemporaneous with this later stage of (1) such moraines as those of the Hidden-Miers ridge (red granite and Vanda porphyry, approximately 1,800 feet altitude) and definitely later moraines as on the Hobbs-Blue Glacier bench were deposited by a large and vigorous glacier. Vulcanism was occurring at this time as a large proportion of the Hobbs-Blue Glacier bench is volcanic material.
3.	The valley (or alpine) glaciers retreated from their former union with the Koettlitz Glacier (possibly the Koettlitz ablated too, but there is no field evidence for us to be sure that tributary and trunk glaciers were synchronous in maxima). The prominent 1,200 feet (approximately) bench of the Koettlitz left bank may have been cut at this stage.
4.	The Koettlitz Glacier re-expended whilst the valley (alpine) glaciers were at or near minimum extent and deposited moraine one-third to half way up their full valley length. Vulcanism was again synchronous as the moraine of this phase is markedly dark with basaltic materiel probably derived from the Mount Dromedary sector of the Koettlitz area.
5.	Since this phase the Koettlitz Glacier has had two periods of notable deposition - a “brown phase” still in place on the glacier wall from Walcott Bay to Marshall Valley and almost equal in altitude with the phase described in (4) and a “black phase” of moraine almost entirely volcanic (Kenyite and basalt) clearly traceable from opposite Heald Island to the Blue Glacier. This is the most recent major morainal deposition of the area and is still ice-cored. To the north where the alpine valley floors are at or below sea level this moraine fills the seaward end of the valley and carries a rugged minor relief of morainal ridges and circular kettle lakes. Cape Chocolate is composed of this moraine.
6.	The above are the main glaciological events of the area but in comparatively recent times the Koettlitz Glacier has again increased slightly leaving complicated evidence in Pyramid Trough where miner vulcanism and moraines are intermixed and further complicated by a “backwash” of ice from the Koettlitz main stream re-entering the Trough from Walcott Bay after passing between the Bulwark and Heald Island. A small increase in the height of the Koettlitz Glacier surface would cause re-occupation of the Trough both from the upstream (southern) and the northern (Walcott Bay) end.

Minor surges of the Koettlitz have built up small fresh moraines on the Walcott Bay coast and on the upstream side of the barrier of Heald Island. These may be contemporaneous with the resurgence of the valley glaciers of the Koettlitz area (observed also in the Taylor Valley and even as far south as the Beardmore Glacier).

Today the glaciers of the Koettlitz area are almost stationary - that is, there has been no notable change in glacier snouts since exploration in Southwest McMurdo Sound began.

Five specimens of dried algae from dried up lakes in the moraines were collected. These will be dated by the C¹⁴ radio-active method and will give minimum ages for these moraines.

Observations of surface movement and ablation were made on the Radian Glacier. During the months of December and January the surface melted about 10 cm. This probably exceeds the local annual precipitation, and the glacier can be maintained in equilibrium only by forward movement. However (subject to recalculation) the glacier in this period did not move forward more than a few cms., and since the surface slope is small, this probably means that this glacier is out of equilibrium and is retreating.