Weathering, erosion rates, and late Cenozoic cooling

Raymo and Ruddiman (1992) advocated mountain building as a driver of climate change. Molnar and England (1990) pointed to the ambiguities of the sedimentary record (increased sediment flux could be triggered by uplift or climate change) and suggested that erosion in response to climate change could drive peak uplift. In Nature this week, Willenbring and von Blanckenburg present a new contribution to the debate on the relationship between climate (specifically late Cenozoic cooling), weathering, erosion and atmospheric CO₂ . They use the marine ¹⁰Be/⁹Be isotope system as a proxy for global weathering rates, and infer steady erosion rates for the last ~12 Myr. Hence, according to their evidence, weathering is not responsible for global cooling, but neither does global cooling trigger enhanced erosion.

Which DEM are you using?

Jonathan de Ferranti maintains Viewfinder Panoramas, which features some interesting discussion of DEM quality issues and virtual globes, as well as his own DEMs for download, and information on other sources of topographic data. Well worth reading, and especially viewing his visual comparisons of how well different datasets (including GoogleEarth) capture some well-known mountains. The image above shows (or rather, doesn't show) Everest as rendered by one of the popular virtual globes...

Useful graph digitising software

DigitizeIt is useful for those times when someone gives you a print out of a graph, you want to compare data from a published plot to your own or you work for an oil company and your data is from the 70s. This is much quicker and easier than reading off values and plotting them yourself, just define the axes and get clicking, then copy data out or make an ascii. It's shareware, not freeware, so the licence is £44.