释义 |
varve /vɑːv /noun GeologyA pair of thin layers of clay and silt of contrasting colour and texture which represent the deposit of a single year (summer and winter) in a lake. Such layers can be measured to determine the chronology of glacial sediments.Each summer/winter pair of layers - called varves - would thus represent a single year....- The basal, coarse layer of a varve is commonly overlain by microlaminared silt and clay, reflecting variable streamflow during summer.
- Analysis of varves (banded sediments in lakes that show annual variation) can be used to date Pleistocene sediments.
Derivatives varved adjective ...- Silt and varved clay, probably deposited during the last stages of Pleistocene glaciation, cover the entire floor.
- In glacial terrains coarse-grained, so-called Gilbert-type deltas of gravels and sands are common, and these pass in deeper water into varved sediments.
- Sediments in many proglacial lakes are varved (annually laminated) and thus offer the same temporal resolution as trees for paleoenvironmental studies.
Origin Early 20th century; from Swedish varv 'layer'. |