Reader's Digest 9月号のRiver Keeperと題された記事からです。
The Atchafalaya runs cleaner and wilder than its big brother, braiding into a thousand bayous and cuts, swirling around countless islands, and passing through the roots of millions of bald cypress trees, willows, and marsh grasses. All that vegetation filters pollution from upstream like a giant feathery fan, while the river itself drops tonnes of silt and sediment along the way, adding miles of new delta to Louisiana.
川が運んで堆積させるものは土砂ですが "silt" はそれに該当するのでしょうか？
・American Heritage Dictionary: A sedimentary material consisting of very fine particles intermediate in size between sand and clay
・Merriam-Webster's: loose sedimentary material with rock particles usually 1/20 millimeter or less in diameter; also : soil containing 80 percent or more of such silt and less than 12 percent of clay
・Cambridge Advanced Learner's English Dictionary: sand or soil which is carried along by flowing water and then dropped, especially at a bend in a river or at a river's opening
粒の大きさを区別する場合は "clay, silt, sand" の順に大きいようです。
語源を見ると：
mid-15c., originally "sediment deposited by seawater," probably from M.L.G. or M.Du. silte, sulte "salt marsh, brine," related to O.E. sealt, O.H.G. sulza "saltwater," Ger. Sulze "brine" (see salt). The verb meaning "to become choked with silt" (of river channels, harbors, etc.) is attested from 1799.
"silt" は "salt" と関係がある事が分かり覚えやすい気がします。
The Atchafalaya runs cleaner and wilder than its big brother, braiding into a thousand bayous and cuts, swirling around countless islands, and passing through the roots of millions of bald cypress trees, willows, and marsh grasses. All that vegetation filters pollution from upstream like a giant feathery fan, while the river itself drops tonnes of silt and sediment along the way, adding miles of new delta to Louisiana.
川が運んで堆積させるものは土砂ですが "silt" はそれに該当するのでしょうか？
・American Heritage Dictionary: A sedimentary material consisting of very fine particles intermediate in size between sand and clay
・Merriam-Webster's: loose sedimentary material with rock particles usually 1/20 millimeter or less in diameter; also : soil containing 80 percent or more of such silt and less than 12 percent of clay
・Cambridge Advanced Learner's English Dictionary: sand or soil which is carried along by flowing water and then dropped, especially at a bend in a river or at a river's opening
粒の大きさを区別する場合は "clay, silt, sand" の順に大きいようです。
語源を見ると：
mid-15c., originally "sediment deposited by seawater," probably from M.L.G. or M.Du. silte, sulte "salt marsh, brine," related to O.E. sealt, O.H.G. sulza "saltwater," Ger. Sulze "brine" (see salt). The verb meaning "to become choked with silt" (of river channels, harbors, etc.) is attested from 1799.
"silt" は "salt" と関係がある事が分かり覚えやすい気がします。
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