The GeoChristian

Lake Eyre, Australia

I love this picture, as only a geologist who loves streams and sediments could.

From NASA’s Earth Observatory site: Rare Refill of Lake Eyre, Australia’s Simpson Desert.

Credit: NASA/Landsat-5

From the EO description:

Waves in central Australia’s Simpson Desert usually come in the form of sand dunes. In these images, they ripple in long vertical lines across the surface of the desert. But occasionally, summer rain from northern Australia flows down into the desert, filling dry river channels and empty lake beds. Very occasionally, the water reaches a vast lake bed called Lake Eyre, turning it into a shallow inland sea where birds flock to breed.

In early 2009, heavy rains brought major flooding to nearly every river system in Queensland, Australia. By May, the water had made its way south and had started to fill Lake Eyre. [This] image provides a natural-color view of water pouring into the lake through one of many channels that drain the desert during the rainy season. The muddy brown water spreads into the lake in a triangular alluvial fan.

Each depositional environment in this image will produce sediments with a distinct combination of grain size, sedimentary structures (various types of ripples and dunes, as well as things like mud cracks), mineralogy (evaporites in the lake basin), and trace fossils (footprints, burrows). The main depositional environments in this image are stream channel, alluvial fan/delta, arid lake, shoreline, and sand dune. Within each of these there are more specific depositional sites, such as near-shore or deeper water lake deposits. These are the types of things that enable geologists to interpret the depositional environments of ancient sedimentary rocks.

Grace and Peace

May 24, 2009 - Posted by geochristian | Geology, Imagery | Australia, Deserts, Landsat