alluvial fan

基本解释

At first light, I started my trek up an alluvial fan into an unnamed canyon in the Cottonwood Mountains.
天刚亮，我就从一片冲积扇区（峡谷山口的扇形沉积物）处开始了旅程，进入了卡顿伍德山脉中的一个无名峡谷。
The portion of the crater where Curiosity will land has an alluvial fan likely formed by water-carried sediments.
好奇号所要降落的陨坑处有一块很可能是由水流沉积物所形成的冲积扇。
Lake Morari on the Tibetan Plateau is fed by a glacial river that has formed a dramatic apron of sediment, known as an alluvial fan, over the years.
西藏高原（TibetanPlateau）上的莫拉里湖（LakeMorari）是由一条冰川河流冲积形成的，长年以来，这条冰川河流在入口处戏剧性地形成了一个围裙形状的沉积泥沙区，被称为冲积扇形地。
uusapp.blog.163.com

There was an alluvial fan at the base of the mountain, for instance, that had some of the same sediments as Eberswalde.
NEWYORKER: The Martian Chroniclers

a fan-shaped accumulation of silt, sand, gravel, and boulders deposited by fast-flowing mountain rivers when they reach flatter land