4 October 2019
The rocks in question are metaconglomerates that Jess Ball and I found at first only as float on the beach at Camp Reynolds, like these two examples:
…Look at those beautiful elongated pebbles, transected by wee white veins!
Where there’s float, there may be outcrop — Sure enough, with a minute or two of searching, we found this same beautiful stretched-pebble conglomerate cropping out to the south, in cliffs along the shore.
Now let’s take a little tangent into looking at deformation within the clasts….
Here’s a close up of one of the deformed pebbles:
Note the set of fractures that are more or less perpendicular to the long axis of the thing; this implies both ductile and then brittle deformation of the clast.
More examples of the same phenomenon:
So that’s a lovely bit of deformation in a metaconglomerate, I’m sure we can all agree. But where are the folds, you may ask?
Here’s one spot – a bit of waviness that has an S-C feel to it:
What’s being folded here is the foliation, defined the shape of the deformed pebbles. Here it is, traced out:
And, in a less severe example, there’s a very slight arching to the foliation here, steeper at bottom left, shallower at upper right:
And here’s some slight warping of one of the stretched pebbles:
Note the varying orientation of the X-axis-perpendicular fractures. It almost looks like a segmented grub, undulating across the outcrop surface!
I hope you find these unimpeachably solid folds, even if they are a bit subtle. Hopefully the rest of the structure in the outcrop is icing on the cake.
Happy Friday to you!