Naked Science Forum
Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: jbetaweb on 12/08/2018 05:43:58
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Hi everyone,
I was hiking up a mountain, and, near the summit, noticed an area of rock that is surprising flat.
In the 1st picture, it's a little bit below in the centre of the photo. The 2nd picture shows it much closer. In the 3rd picture, I am standing on the flat area.
At first, I though that people had gone and cut off a section of the mountain to create a flat area. But when I stood on the flat area, I could not see any signs of human cutting - but if humans had cut the rock, maybe the signs have eroded away.
On the mountain, this is the only place where I saw this distinctive feature, and I want to know if this flatness was somehow made by human cutting, or by some natural process? If this was caused by some natural process, what kind of process would create such a flat area, in a place where everything else is irregularly shaped?
The elevation of the summit in the pictures is 1,449 m = 4,754 ft. The mountain is in the North American Pacific Northwest.
There are a few stacks of rock that are definitely made by people; but how did the large flat area come into being?
Thank you for your answers.
Jason
(https://1.bp.blogspot.com/-LyGAaYawBnk/W2-41cA-lpI/AAAAAAAAAUs/wJQw1XgVwNEZDP7CzflrlD0KDq_T0nh_gCK4BGAYYCw/s320/Picture%2B1.jpg)
(https://2.bp.blogspot.com/-a5mmzVlZw6s/W2-41peuxbI/AAAAAAAAAU0/eMY_tgjl3PoiVyk9lWQMoxiXdMkiURFYwCK4BGAYYCw/s320/Picture%2B2.jpg)
(https://2.bp.blogspot.com/-99lthBkbbqo/W2-41l5uaUI/AAAAAAAAAUw/5ZtAJqMoK5ExNUn88lzJl1zj-dKOIS9QACK4BGAYYCw/s320/Picture%2B3.jpg)
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Possibly differential-erosion of sedimentary rocks (https://en.wikipedia.org/wiki/Sedimentary_rock) of varying hardness ...
https://en.wikipedia.org/wiki/Bench_(geology) (https://en.wikipedia.org/wiki/Bench_(geology))
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Thank you for your thoughts on this. I found the following opinion from an article by a member of the local geological society:
"On the approach to the peak of Mt. Seymour (sometimes referred to as Third Peak) at 1413 m elevation is a glacial pavement of granitic rocks which have been intruded by at least two approximately 3 metre thick dykes of fine-grained dark volcanic rock probably of basaltic composition." ( David Cook, 2017, Self-guiding geology tour in Seymour Provincial Park, p. 11 )
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In picture 3 there are noticeable lineations on the surface of the flat rock- glacial striations? Based on the relative lack of foliation in the flat rock compared to surrounding rock, my guess would be that it may be some sort of younger intrusive rock that is less resistant to erosion than the surrounding rocks.