+ Comments
wind caves - 2009-03-25 18:23:50
| i wasn't going to post this image because it's not one of my best or one of my favorites however people seem interested in the how the formations in yesterday's image were made. the short answer is erosion. a slightly longer answer is i'm a bit hazy on all the details. a much longer answer can be found on the geology page of the Torry Pines State Reserve here. to summarize the information there the land in the area is sedimentary. the park contains 4 ages of rock formations - i think the formations in yesterday's image were deposited by sandbar and later cemented by calcite from water flowing through the sand. eventually water flowing over the cliffs dissolved some of the cement between the quartz grains and wind and water would carry the loose grains away. different degrees of cementing would explain why some parts of the formation wash away before other parts. this doesn't answer why the holes are such perfect circles. the caves in today's image are quite large - i was across a gully taking this photograph but they looked large enough to stand up in. i think the red butte at the top of this image is part of the Lindavista Formation and is 1,000,000 years old. |
N/A 0 sec N/A Flash: Fired |