Introduction To Geology

Our understanding of sand dunes in the fossil record comes from our study of sand dunes in the present. That is uniformitarianism.To start off, I would suggest the wiki page for cross-bedding. It includes pictures of cross-bedded sandstones which are preserved wind blown (eolian) sand dunes.Cross-bedding - Wikipedia

Indeed, they do. However, I happen to live within a very short drive of these wonderful dunes:Bruneau Dunes State Park - WikipediaThey are reportedly the tallest dunes in North America at 470 feet. Interestingly, they do not move and are not the classic mobile crescent shaped dunes. They have remained in their current position since the end of the last Ice Age because the area acts as a trap for windblown sand.

What doesn't change are the laws of physics which underlie the mechanisms that produce wind blown (eolian) sand dunes. We can look at modern sand dunes and use that knowledge to detect wind blown sand dunes in the geologic record. This is uniformitarianism.What is interesting is that some creationists claim that the deposits seen in the Grand Canyon were produced by a recent global flood. One of those deposits is the Coconino Sandstone. This deposit has all of the markings of eolian deposits. IOW, there had to be a desert with wind blown sand dunes during the flood. This seems very problematic, at least to me. {Careful - Starting to head off-topic. This topic is a geology course, not a critique of creationist alternatives - Adminnemooseus} Edited by Adminnemooseus, : Note in red.

I live on the West side of the state. Absolutely wonderful geology in the area. My personal favorite is the amazing weathered tuffs at Leslie Gulch (just across the border in Oregon):http://www.blm.gov/or/resources/recreation/site_info.php?...Near Pocatello is the Craters of the Moon national park where you can check out massive lava fields:Craters of the Moon National Monument and Preserve - WikipediaIn between west and east Idaho you can check out a number of massive and very beautiful canyons that are cut through flood basalts such as this one in Twin Falls (the canyon that Evel Knievel couldn't seem to get across):http://www.idahoreporter.com/...s/2012/01/Perrine-Bridge.jpgI am not a geology expert by any means, but the local geology has always interested me. That is why threads like this one always interest me.

There are deep water corals:Deep-water coral - WikipediaHowever, they are different from shallow water reefs.

It is true that shallow water corals do depend on sunlight because they carry endosymbionts called zooxanthellae. These are photosynthetic flaggelated protozoans that provide the host with energy (e.g. glucose). However, corals are in the phylum Cnideria which also includes jellyfish, hydrozoa, and sea anemones. They are capable of producing energy of their own, and that is exactly what deep sea corals do by feeding on zooplankton and small invertebrates. Like jellyfish and hydrozoa, they have stinging nematocysts that they use to stun their prey.It would be accurate to say that specific species of coral can only live within the daylit portion of the ocean due to their dependence on photosynthesis.