Day #23 Outcrop: Ogallala Caprock, Chalk, Mudcracks & Raindrop Impressions

It’s interesting that my most recent posts in the Deskcrop/Outcrop series have been getting more commentary on Facebook than here on my blog. I’d like to find a way to import those comments back here to the WordPress blog, but I can’t seem to properly configure a Plugin to do the job. Harrumph!

I’m still playing catchup, so short writeups for the next few…

Today’s outcrop is a relatively local one. This escarpment in southwest Rooks County, Kansas is formed where a caprock of Tertiary Ogllala Formation conglomerate (of aquifer fame) unconformably overlies chalk beds of the Cretaceous Niobrara Formation (Smoky Hill Member). Elsewhere in western Kansas this same stratigraphic exposure is exposed with badlands topography developed in the chalk. But not here.

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Ogallala Conglomerate Capping Niobrara Fm (Smoky Hill Member) Chalk, SW Rooks County, Kansas

The other interesting geologic feature at this locality was a beautiful set of raindrop impressions in the mudcracked Quaternary layers on the quarry floor.

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Raindrops & Mudcracks

I believe I’m going to begin to use more Quaternary landforms for some of my upcoming outcrops…