The lake contained muddy water, and the sediment of Lake Vermont contains silt / clay varves, with silt being deposited during summer and clay during the less-energetic flow of winter.
32.
But like with the varves, although the Jehovah's Witnesses I talked to had no explanation for the geographical isolation of the Australidelphia, that didn't actually affect their beliefs.
33.
Turbidites from lakes and fjords are also important as they can provide chronologic evidence of the frequency of landslides and the earthquakes that presumably formed them, by dating using radiocarbon or varves above and below the turbidite.
34.
Unlike dating based on radioactive decay, varves provide a very direct, very simple to understand measure of the geological passage of time, even to people with a very weak understanding of any branch of science.
35.
De Geer called these annual sedimentary layers varves and throughout the 1880s further developed his theory, publishing a brief outline of his discovery in 1882, which he followed with a presentation to the Swedish Geological Society in 1884.
36.
Crawford Lake is meromictic, which means it has sequentially-deposited seasonal sediment laminations called varves at the bottom; these allow for accurate dating of sediment cores and make Crawford Lake a prime site for archeological and geochemical studies.
37.
Wilmot H . Bradley showed that annual varves in lake beds showed climate cycles, and A . E . Douglass found that tree rings could track past climatic changes but these were thought to only show random variations in the local region.
38.
Paleoclimatology dates back to the 19th century, and the concept of examining varves in lake beds and historical documents and temperature records of central England to propose a Medieval Warm Period from around 900 to 1300, followed by Little Ice Age.
39.
The wedges may have formed in a relatively short period of time, perhaps no more than a few hundred years, as indicated by the annual deposition cycles in glacial lakes ( known as "'varves "') within the moraine sediments.
40.
Because of this lack of physical mixing, as well as the absence of growing plants or crawling animals in their oxygen-depleted depths, the deep bottoms of the lakes have relatively undisturbed annual layers of sediment ( or varves ) that preserve a historical record, somewhat like tree rings do.
