29 March 2013

Friday fold: “V”

Posted by Callan Bentley

Apologies for the delay in posting the Friday fold – I got an early start this morning in order to do some GigaPanning at the new outcrop that John Singleton (GMU) and I discovered the week before last. Here’s an action shot from the morning’s efforts:

Click to enlarge.

That’s the GigaPan working hard at capturing a V-shaped syncline in the Martinsburg Formation (Ordovician-aged turbidites). The syncline was most likely superimposed on these strata during the late Paleozoic Alleghanian Orogeny. Make it bigger, if you want. Or you can wait for the GigaPan itself.

An annotated view follows:

Note the grading visible even at this low-resolution in the yellow-highlighted bed (crisp bottom, but gradationally more cleaved as you go up towards its muddier top), and the cleavage refraction at far left (blue annotations) as it crosses quartz-rich sand layers and clay-rich mud layers.

Happy Friday. With V-shaped synclines like this one to flavor the day, you know it’s going to be a Good one!