Event Map

Figure 1 is a detailed sketch map of the Table Mountain area, showing the camp site and the locations visited by helicopter (Platform Spur and Sickle Ridge). Other areas mentioned in the diary are also indicated.

During our expedition, we noted in two instances that the measured altitude was approximately 500 feet (150 m) higher than what was printed on our maps. Upon landing at Table Mountain, we measured the altitude using an altimeter set at Scott Base. Our reading of 2338 m was significantly different than the 2183 m on the 1:50,000 USGS-DOSLI topographic map (1993, Cathedral Rocks sheet) and radically different from the 1800-1900 m on the topographic base of the geologic map (Geology of the Knobhead Area, Woolfe et al., 1989). In addition, during helicopter transport to a sampling locality to Sickle Ridge the helicopter altimeter read ∼10,000 ft, whereas the map (Woolfe et al., 1989) indicated 2800-3000 m (∼9000-9500 ft). This particular error was costly in terms of helicopter time because the pilot refused to land on top of the ridge and the field party was dropped at the next lowest site (∼9,000 ft) and it was necessary to climb (this took time) up the 1,000 ft to the sampling site while the helicopter waited. The pilot was following regulations that require oxygen for the crew at altitudes above 10,000 ft. Oxygen was not brought on the mission, because it was believed the site was ∼9,000 ft.

A labelling error was spotted on the 1:50,000 USGS -DOSLI topographic map (1993, Cathedral Rocks sheet). 'Navajo Butte' was placed at a feature marked 2183 m elevation (actually, the location of our camp!), approximately 1 km northeast of its correct location (feature marked 2263 m).