CGRG Bibliography of Canadian Geomorphology
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Author : Francus, P.
Date : 2009.
Title : Varved records from deserts: Good complements for tree ring based reconstructions?
Publication : 2009 American Geophysical Union Fall Meeting. December 14-18, 2009. San Francisco, California, USA.
Issue :
Page(s) :
Abstract
Many of the recent paleoclimate reconstructions of the last millennium mainly rely on tree-ring records that more or less cover evenly most of the continental masses. However, North of the tree line and in large hot deserts, only lakes with varved sediments are able to provide annually resolved information about past climate variations. This paper discusses some of the differences of such records with the ones obtained from tree-rings and is illustrated by examples from sites in the Canadian High-Arctic and the Sahara. Many sedimentological, physical, paleontological and chemical parameters can be measured in lacustrine sediments at the lamina scale but also at lower resolution. Therefore, varved sequences potentially record a wide variety of climate variables such as temperature, precipitation, catastrophic hydrologic event or wind intensity. Unlike tree rings, the recorded signal is not similar within homogeneous geographical regions. Each lacustrine system is indeed different and requires a comprehensive understanding of the lake and its watershed in order to obtain quantitative reconstructions. Some varved sequences are several millennia long and are therefore good at capturing the low frequency modes of variability of the climate system, including solar activity. Climate reconstructions including both varves and tree-rings records will have to take these differences into account.
Bibliography of Canadian Geomorphology