Talus deposits

What the map says

Angular pebbles to large boulders deposited chiefly by rock and snow avalanche, rockfall, rock slide, and debris flow at base of cliffs and steep slopes where debris forms aprons, cones, and fan-shaped deposits. Locally includes debris flow and rubbly scree deposits. In cirques, locally includes tills of the Satanta Peak and Triple Lakes advances of Benedict (1985), about 12–10 ka (Davis, 1988), and tills of Holocene age near cirque headwalls (Benson and others, 2007). Much of the talus in glaciated valleys and cirques postdates the retreat of Pinedale ice. Some of the talus derived from the Fountain Formation (Phf) south of Boulder may be of middle Pleistocene age. Estimated thickness 3–15 m

1:100,000 sheet: Kellogg and others, 2008, USGS Geologic Investigations Series 3000 (6 crags). A contact line at that scale is about 100 m wide on the ground.

Large angular boulders and smaller rock fragments deposited chiefly by rock and snow avalanche, rock fall, rock slide, and debris flow at the base of cliffs and steep slopes where debris forms aprons, cones, and fan-shaped deposits. Unit locally includes rubbly scree deposits and probably tills of Holocene age near cirque headwalls (for example, Benedict, 1973a; Benson and others, 2007). Much of the talus in glaciated valleys and cirques postdates the retreat of Pinedale ice. Unit Qta is mapped chiefly in alpine and subalpine areas along the crest of the Medicine Bow Mountains and Never Summer Mountains, and in the upper part of the Cache la Poudre River valley upstream of Kinikinik. Small talus deposits adjacent or surrounded by colluvium (Qc) are mapped as colluvium. Estimated thickness is 3–15 m Lithology: colluvium.

1:100,000 sheet: Workman and others, 2018, U.S. Geological Survey Scientific Investigations Map 3399 (1 crag). A contact line at that scale is about 100 m wide on the ground.

Served by Macrostrat (CC BY 4.0). The wording is the map's own, quoted as a fact about the mapped unit, not about any one wall.