Mars lakes and riverbeds. The Mars rover has reached the base of the central mountain in the Gale Crater after 747 Martian days. The latest images show the rover weaving its way along what appears to be stream beds cut into the layers of sediment that collected at the bottom of a lake. Particles of dissolved rock appear to have been washed in, probably from outside the rim of the crater walls at various times, each time, putting down a new layer of sediment on the lake floor, which eventually turned to stone, just like sandstones on Earth. Each flaky layer in the rocks represents some sort of cyclical rain or storm process that transferred tiny rock crystals from elsewhere, either from inside or outside of the crater walls. Tiny talcum powder sized grains travel farther than larger grain size rock materials. Billions of years of Martian wind erodes the layered rocks, so that they look like wave layers. The tops of the rocks get eroded more than the lower layers. And sometimes more sturdy rock layers get undercut, so they look like theyre pieces of cardboard sticking out. And Mount Sharp, the craters very large central peak is one of the big questions. It shouldnt really be there based on crater impact studies. It should be much smaller Also, midway up the mountain theres an angled layer thats called an unconformity in geology. Since sedimentary rock layers form horizontally, how did an angled layer find its way between two horizontal formations ... on a mountain? So, it looks like Mars had a heck of a lot of water moving rock materials around for the first billion years of its existence. It must have rained and snowed with varying seasons. Theres also evidence of glacier movement on various parts of the planet. For Mars to have running water, it had to have some sort of atmosphere with greenhouse gases like CO2 and methane, otherwise at Mars distance from the sun, all water would be frozen. As far as finding evidence of past or present living things, that may have to wait until the 2020 rover mission which will use the same rover configuration but with different science instruments.
Posted on: Sun, 14 Sep 2014 16:27:41 +0000