Naked Science Forum
Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: ichnos on 16/04/2007 18:16:10
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Hi, does anyone know of any work that looks at the orbitally induced effect in sequences of non-marine strata? homework assignment [;)]
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Does this mean strata that are layed down differently at different parts of the orbit eg seasonally?
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There is work on glacial ice in both Greenland and Antarctica, lacustrine sediments from around the world, and a lot of references on-line. Just Google "orbital forcing." It is SOMETIMES seen in coal deposits. As these effects are due to perturbations in the earth's orbit, the cycle time of the deposits will be in 100's of thousands of years so the non-marine deposits must have been persistent over a long period of time.
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I am aware of the work on ice cores and on lacustrine seds, and the effect in these deposits suggests that it may be recorded in terrestrial sediments i.e fossil soils. I heard there was a guy at l'ecole des mines who had recorded orbital forcing (the larger time periods of eccentricity and obliquity) in fossil soils, but can not find any published work on this in pre-quaternary rocks. any leads?! [:)]
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I think some work has been done on the Washington scab lands. There may also have been some on the glacial outfall from the continental glaciation in the Mississippi valley. The problem with soils reflecting the Milankovich Cycle is that they are not very well preserved.
Other data has been gathered in the south west US by the analysis of Pleistocene rat burrows. Don't remember people or places - I just skim the journals until there is something about sedimentation or tectonics that catches my eye.
Wish I could be of more help. Wait - check the Australian National Survey. It has been arid there for a long time and something in the back of my skulls says to look down under.