Research press release


Nature Communications

Earth science: Ancient river lost in the sands of time



今回、Charlotte Skoniecznyたちは、地球上空の軌道を周回し、砂丘のような深さ数メートルの物質を探査できるレーダー衛星の画像を用いて、砂丘の下に隠れている地質学的特徴の位置を明らかにした。Skoniecznyたちは、この手法を用いて、全長約520 kmの広大な古代の河川網の存在を明らかにした。この河川網は、隣接する海岸線上にすでに同定されている海底峡谷とほぼ完全に一致している。


The sandy wastes of the Western Sahara once accommodated a vast river network, according to a study published in Nature Communications this week. The findings have important implications for our understanding of the African continent under past and future climates.

Today, no major river systems exist in the Western Sahara, only a constantly shifting sea of sands. However, recent findings have suggested that this has not always been the case. The discovery of fine-grained, river-borne material in the deep ocean, and an extensive submarine channel carved into the continental shelf off the Western Sahara coast, indicate the past existence of a major West African river system. However, direct evidence of such a vast fluvial network on land has been lacking.

Charlotte Skonieczny and colleagues use orbital radar satellite imagery, which has the capability to penetrate metres of material, such as sand dunes, and map the geological features that lie hidden beneath. Using this technique, the team reveal the existence of a vast ancient river network approximately 520 km in length, which aligns almost perfectly with the submarine canyon previously identified on the adjacent coastline.

The findings have important implications for the way in which sediment records off West Africa are interpreted and for our understanding of an ancient, wetter, and possibly greener, Sahara.

doi: 10.1038/ncomms9751

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