alluvial deposits造句

• The farmers found the alluvial deposits at the mouth of the river very fertile
  農民發現這條河口底下的沉積物很肥沃。
• Tian shan extends east - west in central asia , the tian shan range was formed in later paleozoic , and a few intramontan basins appeared in mesozoic . it uplifetd again in early miocene because of the north - south compression induced by the india - asia collision , so many active structures can be found in tian shan . active tectonics took actions during last ten thousands yeas , and surface traces of fault scarps , detached gullies and folds in alluvial deposit are apparent , so it is easy to distinguish them from other geological phenomema
  天山位于亞洲中部，天山造山帶形成于晚古生代，到中生代時，在天山內部形成了一些山間盆地，印度板塊在始新世向北與歐亞板塊碰撞，天山受南北向擠壓力的作用再度于早中新世隆起，由于板塊碰撞的持續進行，在天山山間及山前發育了許多的活動構造。
• It's difficult to find alluvial deposits in a sentence. 用alluvial deposits造句挺難的