By Paulette Cully
Being a geomorphologists at heart (which is the study of landscapes and the processes which shape the earth’s surface) I enjoy reading about the methods used to reconstruct past environments and geomorphic events. A detailed understanding of how the earth surface is being continuously shaped and why it looks the way it does are essential requirements for an evaluation of geomorphic processes and related changes in space and time. This is especially important in order to predict how climate change may potentially affect the frequency and volume of earth-surface processes. However, direct observations and evidence of past occurrences are scarce and data is patchy. It was, therefore, with some excitement that I read a recent news article on this subject which reports how information gleaned from sediment cores from the bottom of Lake El’gygytgyn in north-eastern Siberia have revealed the most continuous record of ancient climate ever extracted from the terrestrial Arctic. In addition, the samples also disclosed what happened 3.6 million years ago when a large meteorite struck the site when the area was warmer and forested. In contrast, today the area is a region of tundra and the crater generated by the meteorite has since filled with water to become the lake.
For those of you keen to learn more about reconstructing past environments, it is recommended to read ‘What tree rings can tell us about earth-surface processes: Teaching the principals of dendrogeomorphology’ in ‘Geography Compass’ (2009). In their article, Stoffel and Bollschweiler provide a fascinating discussion of dendrochronology, or tree-ring analysis, which is one of the most precise and accurate methods for dating various geomorphic processes. This is because it allows scientists to define incidences with at least a yearly precision. As a result, dendrochronology has become the mainstay for Holocene (from 12,000 years ago to the present day) chronology reconstructions. The article provides an overview on how trees are affected by earth-surface processes, on how they are used in the analysis of geomorphic processes and on what they can reveal about the occurrence and evolution of geomorphic processes in time and space.
Click here to read the article about Lake El’gygytgyn
Geography Directions 