[1][2][3] Andes peak heights in the region are generally less than 1,250 metres (4,100 ft) above sea level.

During the Last Glacial Maximum (LGM), approximately 20,000 years ago,[4][nb 1] a valley glacier carved the Carbajal-Tierra Mayor valley (described as the "glaciation axis of the Fuegian Andes")[7] from northwest to southeast, with an ice tongue forking south along the Valle Río Olivia into the Beagle Channel immediately to the east of Ushuaia.

[8] Based on the geological study of the erosion patterns, the Carbajal glacier’s ice thickness was 600–800 metres (2,000–2,600 ft).

[8] By the middle Holocene period (8,200–4,200 years ago),[11] forest growth was expanding.

[8] The nearly U-shaped valley floor is covered with Sphagnum peat bogs and poorly drained mires.