Scientists have developed a new diagnostic tool that will enable better understanding of global climate patterns.
By distinguishing whether debris in glacial deposits originates from climatic or rock avalanche processes, the development allows for more accurate data to inform paleoclimate reconstructions of climate models.
The development, detailed in Geology last month, represents a breakthrough in the fields of both landslide (rock avalanche) research and our interpretation of climate change from glacial deposits, and found the assumption that glacial deposits always reflect climatic change was unreliable.
Monash University’s Dr Stuart Larsen, jointly based at the School of Biological Science and School Geography and Environmental Science, collaborated with researchers from The University of Canterbury and University of Queensland on the development.
The study revealed the cause of glacial deposits was more complex than originally thought and some deposits identified as being of climatic origin were found to be the product of the deposition of rock avalanche debris on glaciers, Dr Stuart Larsen said.
“Glacial deposits provide a vital proxy for past climates, and it was previously assumed that they always reflected climatic change,” Dr Larsen said.
“However, glacial deposits cannot accurately be used for climate change studies without first understanding their origin.
“Through this new technique, we were able to differentiate whether glacial deposits are purely the product of climatic factors or resulted from rock avalanches.
"Many glaciers of the Southern Hemisphere occur in seismically active mountain ranges, with many rockfalls, and this new technique could lead to a new reconstruction of past climate change.”
The new diagnostic tool was tested on glacial deposits from around the world, including glaciers near Mt Cook in New Zealand, previously used to infer past climate changes.
These were shown to contain rock-avalanche material, and their dates were coincided with past Alpine fault earthquakes, leading to the possibility the rock avalanches might have been earthquake-triggered.