Underlying Statistical and Physical Mechanisms of Lake Sedimentation
Abstract
The formation of annually laminated sediments (varves) in lakes has been investigated for underlying statistical and physical mechanisms. Time series analysis of varve thickness variations during the last 15,000 cal yrs BP from lakes in Europe, the Arctic and North America indicate sedimentation can be considered in terms of the "quantity" and the "stratigraphic position" of the sedimentary deposit. Probability density functions indicate the "quantity" varve thickness time series are non-Gaussian and are fitted well by gamma and log-normal distributions. Power spectra, autocorrelation functions, fluctuation analysis indicate the "stratigraphic position" is scale invariant over three to four orders of magnitude, with average ca. H = 0.7. Random walk, (self-organised) critical phenomena, and multiscaling are suggested as underlying mechanisms. These results suggest varve formation is represented by a series of random depositional events, in a critical multiplicative cascade. A physical model is proposed to account for these statistics.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2001
- Bibcode:
- 2001AGUFMNG31B0371H
- Keywords:
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- 3220 Nonlinear dynamics;
- 4239 Limnology