Some readings over the past few weeks:
1) An Earthquake Changed the Course of the Ganges. Could It Happen Again? Sediment load carried by big rivers like the Ganga often choke up channels and force the river to cut another path. Sudden channel shifts can also occur due to tectonic movements. A recent survey of the Ganga about 100 km south of Dhaka, Bangladesh , identified an old channel of the Ganga. Exploring this area, researchers came across veins of sand cutting across the sediment layers. These veins or sand dikes were injected into the surrounding sediment. They are a sign of major ground trembling triggered by a large earthquake. Ground motion may pressurize buried sand and inject it upwards. Further studies showed that this event may have been a 7-8 magnitude earthquake that occurred 2500 years ago. Kevin Krajick writes about this discovery and the larger geologic context.
2) Lessons from the Nile about rivers and society. The Nile river has sustained agriculture, human habitation, and royal dynasties for millennia. A Nature Geoscience editorial summarizes a collection of sedimentological and geomorphologic studies that track the evolution of the Nile through the Holocene. Phases of the river cutting a deep valley changed to phases of the river flooding laterally and building fertile floodplains. This geomorphological evolution driven by climate change and more recent dam building have influenced agriculture and social systems in the past as well as the present.
3) Ocean Exploration: Meet The Deep. I highly recommend this site. National Ocean and Atmospheric Administration, U.S.A., has compiled some stunning photographs and videos of deep sea habitats and the diverse forms of life that inhabit this little understood world. Corals, sponges, brittle stars, molluscs, worm tubes- attached to the bottom, living around energy sources such as hydrothermal vents and cold seeps. It is an absolutely fascinating exploration of the biodiversity of the deep sea.
Octocoral and Brittle Star: Source NOAA Ocean Exploration
As a bonus, these images make great wallpaper for your mobile phone!
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