Assertion: alluvial fan's surface | /r/CapableOf | form a segment of a cone
Facets:
Source sentences:
text: Alluvial fans accumulate at the base of a mountain front or other upland area where an emerging mountain stream deposits a sediment body whose sloping surface forms a segment of a cone (Blissenbach, 1954; Bull, 1972a, 1977; Fig. 1).