Usas Escarpment () is an expansive but discontinuous north-facing

escarpment An escarpment is a steep slope or long cliff that forms as a result of faulting or erosion and separates two relatively level areas having different elevations. Due to the similarity, the term '' scarp'' may mistakenly be incorrectly used inte ...

Marie Byrd Land Marie Byrd Land (MBL) is an unclaimed region of Antarctica. With an area of , it is the largest unclaimed territory on Earth. It was named after the wife of American naval officer Richard E. Byrd, who explored the region in the early 20th centu ...

, Antarctica. It is about long, extending roughly west to east along the

76th parallel south Following are circles of latitude between the 55th parallel south and the 80th parallel south. The 55th parallel south, crossing the southernmost point of Chile, is the last line of latitude moving southward to touch any part of any continent oth ...

from where the elevation of the snow surface descends toward the

Ruppert Coast Ruppert Coast () is that portion of the coast of Marie Byrd Land, Antarctica, between Brennan Point and Cape Burks, or between Saunders Coast in the west and Hobbs Coast in the east. It stretches from 146°31'W to 136°50'W. It was named by R. ...

and

Hobbs Coast Hobbs Coast () is that portion of the coast of Marie Byrd Land, Antarctica extending from Cape Burks to a point on the coast opposite eastern Dean Island, at , or between the Ruppert Coast in the west and the Bakutis Coast in the east. It stretch ...

. The position of the escarpment coincides with the north slopes of the

Flood Range The Flood Range () is a range of large snow-covered mountains extending in an east–west direction for about and forming a right angle with the southern end of the Ames Range in Marie Byrd Land, Antarctica. Location The Flood Range is south ...

Ames Range The Ames Range () is a range of snow-covered, flat-topped, steep-sided mountains, extending in a north–south direction for and forming a right angle with the eastern end of the Flood Range in Marie Byrd Land, Antarctica. Location The Ames R ...

McCuddin Mountains The McCuddin Mountains are a small cluster of mountains in Antarctica consisting mainly of two large mountains, Mount Flint and Mount Petras, along with several scattered peaks and nunataks. Located in Marie Byrd Land, east of the Ames Range, wi ...

, and the eastern peaks of Mount Galla, Mount Aldaz and Benes Peak.

Location

The western end of the range is north of the

Executive Committee Range The Executive Committee Range () is a range consisting of five major volcanoes, which trends north-south for along the 126th meridian west, in Marie Byrd Land, Antarctica. Location The Executive Committee Range is south of the eastern end of ...

. Mount Galla is towards the northeast end. Mount Aldaz and Benes Peak are further to the east.

Exploration and name

The escarpment was observed by members of the

United States Antarctic Service The United States Antarctic Program (or USAP; formerly known as the United States Antarctic Research Program or USARP and the United States Antarctic Service or USAS) is an organization of the United States government which has a presence in the ...

(USAS), 1939–41, and in ensuing scientific reports was referred to as 76th Parallel Escarpment. The approved name is an acronym for the discovery expedition.

Features

Features of the eastern end of the escarpment, from west to east, are

Mount Galla

. Snow-capped mountain high which rises above the Usas Escarpment, east of Mount Petras in the

. Mapped by the

United States Geological Survey The United States Geological Survey (USGS), founded as the Geological Survey, is an agency of the U.S. Department of the Interior whose work spans the disciplines of biology, geography, geology, and hydrology. The agency was founded on Mar ...

(USGS) from surveys and United States Navy air photos, 1959-65. Named by the United States

Advisory Committee on Antarctic Names The Advisory Committee on Antarctic Names (ACAN or US-ACAN) is an advisory committee of the United States Board on Geographic Names responsible for recommending commemorative names for features in Antarctica. History The committee was established ...

(US-ACAN) for Lieutenant Edward J. Galla, United States Navy, who was medical doctor and leader of support personnel at Byrd Station, 1959.

Mount Aldaz

. A projecting-type mountain high that barely protrudes from the ice-covered Usas Escarpment, east-southeast of Mount Galla. The mountain is mostly ice covered, but has notable rock outcropping along its northern spur. Surveyed by USGS on the Executive Committee Range Traverse of 1959. Named by US-ACAN for Luis Aldaz, Meteorologist and Scientific Leader at Byrd Station, 1960.

Benes Peak

. A peak high that is almost entirely snow covered, situated along the Usas Escarpment, east of Mount Aldaz. Surveyed by USGS on the Executive Committee Range Traverse of 1959. Named by US-ACAN for Norman S. Benes, USARP meteorologist at Byrd Station, 1961.

References

Sources

* *{{Include-USGov , agency=United States Geological Survey Landforms of Marie Byrd Land Escarpments of Antarctica