Met this rock this weekend. Rensselaer Plateau, Rensselaer Co. NY. (north america) what is going on? to the left is a rather tough grainy sedimentary rock, blends into foliated rock with flat cut face and black and white weathering, and then to right, finer grained rock.  The general rock type here is called Graywacke, which seems to me to be garbage pail rock. Whatever falls into the sea and turns into rock, counts.  In a 60 foot stretch of this along the road it morphed into so many textures... born in deep sea and shoved over the continent when an island arc smashed us 500my ago.

 file:///media/barry/3434-3835/phNew/newPhPics2026_04/20260411_174657.jpg

 

Here is a closeup. VERY messy. to the left is friable rock with layers facing us, but the layers leaving the white weathered lines is perpendicular to that.  I guess it is turbulent in the deep sea. 

 

 

more textures all within a few feet of each other

   

Dunno how this bit formed.  Squiggly yellow green stuff, epidote?

   

this is only a tiny taste of all the morphs that this Rensselear Plataeu Graywacke does.

 Tried to find an online summary of the place but they don't make a LOT of sense.  The geology of the Taconic orogeny is still confusing.

Something Happened Under a Long Lost Ocean

Ok, here's a  picture of my most recent rock.  it's the bedrock behind the Troy Middle School track, New York State, North America.  Transition zone between blobby limestone and flaky shale.  All from deep in the ancient Iapetus Ocean before it got smushed closed 440 million years ago during the Taconic Orogeny (mountain building).

https://en.wikipedia.org/wiki/Taconic_orogeny

There is a story embedded in this rock, but I'm not sure what it is!  When did the limestone get laid down?  When the shale?  When did they get smashed together like that?  During an earthquake that tumbled the limey ooze and clay mud together higgledy piggledy under the ocean or afterwards when they turned to stone and got shoved up on top of our continent?  Mysteries recorded in the rock.