alluvial fan

基本解釋

At first light, I started my trek up an alluvial fan into an unnamed canyon in the Cottonwood Mountains.
天剛亮，我就從一片沖積扇區(qū)（峽穀山口的扇形沉積物）処開始了旅程，進(jìn)入了卡頓伍德山脈中的一個(gè)無名峽穀。
The portion of the crater where Curiosity will land has an alluvial fan likely formed by water-carried sediments.
好奇號(hào)所要降落的隕坑処有一塊很可能是由水流沉積物所形成的沖積扇。
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）上的莫拉裡湖（LakeMorari）是由一條冰川河流沖積形成的，長(zhǎng)年以來，這條冰川河流在入口処戯劇性地形成了一個(gè)圍裙形狀的沉積泥沙區(qū)，被稱爲(wèi)沖積扇形地。
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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