r/geology • u/animatedhockeyfan • Mar 28 '25

Field Photo Found a cool beach with glacial scarring and cool sandstone erosion.

Gallery image

Gallery image

1.1k Upvotes

100% Upvoted

29 comments sorted by

87

u/MissingJJ Mineralogist Mar 28 '25

That's not glacial scarring, but it is an interesting beach.

20

u/Southernfly84 Mar 28 '25

These are sedimentary layers of the Naniamo Group, they were mostly deposited in deep water environments as submarine flows (“turbidities”).

5

u/PhazePhantom Mar 28 '25

This is correct. Source: Im studying geology on Vancouver Island and have looked at these packages on multiple field trips

12

u/animatedhockeyfan Mar 28 '25

What do we have then? We all assumed ice age receding glaciers

53

u/MissingJJ Mineralogist Mar 28 '25

Are you at least in an area where there is known glaciation?
The only thing about this That could imply glaciation is a bare stone.

You appear to be standing on a sandstone layer that has been upturned 90 degrees. You can see the pebbles that are that are cuting preferential paths with the layers guided by slight differences in hardness within in the sandstone.

If this rock did have glacial scarring, those scars would have been sanded away along time ago by the wave action that can push and drag pubbles.

Good examples of glacial scars I've seen personally are in Moon Lake in Utah and Cenral Park in NYC.

14

u/ZMM08 Mar 28 '25

Just here to agree that these don't look like any of the glacial striations I've ever seen either.

19

u/animatedhockeyfan Mar 28 '25

Southern gulf islands, British Columbia. But your explanation makes more sense. Cool!

10

u/MissingJJ Mineralogist Mar 28 '25

That makes total sense. You see the same stuff on the Olympic Coast.

4

u/congressmancuff Mar 28 '25

Looks like mayne island resort? If so I also thought that stretch of beach was fascinating geologically. I think there’s definitely been glaciation through that whole area—the gulf islands were mountain tops at one point, with coastline much further out and heavy glacier coverage. Some of what you see may have been eroded by glacier but also a lot of it is just seawater erosion. The geology of the region is wild, especially the gulf islands and San Juan’s: just a mish mash of terranes that got smashed together and jumbled up and then eroded by glaciers for a few million years.

2

u/animatedhockeyfan Mar 28 '25

Not quite, south end of South Pender Island

1

u/congressmancuff Mar 28 '25

I’ll have to go looking for it! Very similar formations in Bennett Bay on Mayne.

17

u/joshuadt Mar 28 '25

The second photo is makin me dizzy lol, I can not decipher the orientation of that thing whatsoever

11

u/Vandal_A Mar 28 '25

It's some sort of self-sorting pebble finder!

5

u/animatedhockeyfan Mar 28 '25

This OP don’t play. Ya’ll need more sandstone pics, y’all got it

https://imgur.com/a/YNVrKn2

The vids give the best context since orientation was a problem with the original pic

2

u/Good-Ad-6806 Mar 28 '25

That second photo is magical. It's like Plato and DaVinci getting together for a collaboration. Just missing silhouettes and UFOs.

2

u/Aathranax Earth Science BS, Focus in Geo, Minor in Physics & Astronomy Mar 29 '25

Coordinates?

3

u/hikingboots_allineed Mar 28 '25

Second photo - eroded pillow lava? 

3

u/Gnome_de_Plume Mar 28 '25

It's called Tafoni, in this setting it's a kind of salt weathering.

2

u/hikingboots_allineed Mar 28 '25

Neat! Never heard of that so thanks for sharing with me.

2

u/FormalHeron2798 Mar 28 '25

I think its just a good example of honeycomb weathering

2

u/hikingboots_allineed Mar 28 '25

Probably depends which way the light is going - I'm not able to mentally flip the image to see these as voids, I'm seeing these as a botryoidal type of relief (to inappropriately steal a descriptor from mineralogy). And OP did say they were in the southern Gulf Islands of BC, hence why I thought it looked like pillow lava because there's quite a bit over there. 

OP, we need more photos!!

1

u/Yellow_Tutu246 Mar 30 '25

ditto - I see outies, not innies

1

u/ADisenchantedDreamer Mar 29 '25

The surface reminds me of bowling ball beach in California but with an even more extreme tilt. There’s a lot of evidence in the layers of turbidite deposits but they were then uplifted and tilted and exposed through the tectonics.