Butcher Ridge, Cook Mountains

Butcher Ridge in Fig. 18.8 is located at the very edge of the polar plateau in the Cook Mountains (79°25 S, 158°(X) E) north of the Darwin Glacier in the 

Transantarctic Monntains of sonthem Victoria Land. It consists of a semi-circnlar ridge with a steep eastfacing cliff that extends north from Mt. Ayres (2,498 m, 79°20 S and 156°28 E) for abont 23 km. The arc of Butcher Ridge in Fig. 18.9 partly encloses the Finger Ridges including Harvey Peak (2,120 m, 79°13 S and 157°01 F). 

The geology of this part of the Transantarctic Mountains, described by Grindley and Laird (1969), consists of flat-lying quartz sandstones of the Beacon Supergroup that were intruded by sills of the Ferrar Dolerite. These rock units are underlain by the granitic basement rocks of the Granite Harbor Intrusives that are exposed in the Brown Hills along the coast of the 

Ross Ice Shelf (Section 3.3). Haskell et al. (1963, 1965) mapped the granitic basement rocks and overlying Beacon rocks in the Brown Hills and Darwin Mountains, but they did not include Butcher Ridge in their study area. 

The geology of Butcher Ridge turned out to be unexpectedly complex with a wide range of rock types which Marshak et al. (1981, p. 54) described as  

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Although large meteorites have certainly impacted in Antarctica, only one such crater has been tentatively identified under the ice at about 71°30 S, 140°00 E in Wilkes Land south of the Adelie coast. Another more speculative meteorite impact crater may exist at Butcher Ridge (79°12 S, 155°48 E) in the Cook Mountains of southern Victoria Land. 

Fig. 18.8 Aerial view of Butcher Ridge of the Cook Mountains at the edge of the polar plateau. The view is to the south. Butcher Ridge is in the foreground (Photo by G. Faure)...

Fig. 18.9 Butcher Ridge at the edge of the polar plateau in the Cook Mountains of southern Victoria Land is composed of highly contorted and layered rocks consisting of glass and apha-nitic rocks ranging from basalt to alkali-rich rhyohte. Although they resemble volcanic rocks, they formed by mixing of melts of basaltic and felsic composition followed by rapid cooling. The petrogenesis of these rocks is not understood. However, they...

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