Here we have alternating bands of shale and marble (or approximately marble). These were laid down in deep ocean between what used to be the east margin of the North American Continent and a volcanic Island arc east of it. Alternating climate conditions (say every 10s of thousands of years) made it possible for carbonates (coral reef? sea shells..) to form or simply muds. The carbonates become limestone then marble, the mud becomes shale.
Other processes are storms, rivers, earthquakes that send sediments tumbling down to the sea.
Eventually, the Island arc smashed into us and broke these sediments into various blocks and piled them on top of each other and against North america. Now they are part of NY state. I think most of this is called the Taconic Allochthon, though I've seen it called many things.
There are many examples of this Taconic Allochthon around Troy, NY where I live. There is LOTS of variation! Most not exciting as this one.
Here are some tons of layers, some as thin as paper. I'd love to learn to do some chemical analysis and figure out what each layer is made of. The different colors no doubt relate to organic material or iron minerals in various states of oxidation (i.e. was it black anoxic smelly sulfurous mud deep under the water or something more oxidized at the surface?).
One day I'll consult with the geologists and find out exactly what peice this is.
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