Thursday, 22 October 2020

Rain Erodes Mountains - Measured and Modelled

 Rain Erodes Mountains - Measured and Modelled

Geomorphology was never like this in my day! A correspondent has brought THIS ARTICLE to my notice - thank you! It is based on THIS JOURNAL PAPER. The research area was Bhutan. 

Rain erodes mountains. Does the removal of material cause mountains to rise because of isostasy? This has been discussed for ever - or so it seems!

The papers describe an attempt to measure this. As you might expect, this is not easy. relief and rainfall at fairly easy to measure but erosion rates are more difficult. The method used here is to measure chemical changes in quartz sand caused by cosmic rays. This goes by the name "detrital cosmogenic nuclide erosion rates".
Presumably fewer changes mean faster erosion. The longer the sand is on the surface the more cosmogenic nuclides and slower erosion.

It is thought that erosion rates are roughly equal to uplift rates as the landscapes are thought to be in equilibrium.

The papers quantify how rainfall affects erosion rates in rugged terrain. And that tectonic activity is affected by rainfall!

The geomorphology i was taught was a descriptive subject. Reading this paper shows thait has changed! But you still get to go to interesting places.

No comments: