Geology of RdV vineyard and winery

Last month, I led a fun new tour for the Smithsonian Associates: an all-day tour of the geology of Virginia wine country. Wine-making is a bigger-and-bigger business in Virginia these days, and I’ve been exploring it on and off over the past few years, ever since participating on a wine-themed geology field trip through the Geological Society of Washington. So we got a bus, and I waxed on about the Grenville Orogeny and the rifting of Rodinia, and before you knew it, we were in Paris, Virginia. Our first stop was a vineyard on a hill, and the elegant winery building seen here:

This is “RdV” – and it’s a lovely place to visit. Very impressive in almost every detail.

My concept for the tour was this: visit three different wineries, each in a distinctly different geologic setting that tells the story of the Mid-Atlantic region over the past billion years of geologic time. The rock at the RdVsite is an alkali syenite – the Cobbler Mountain alkali feldspar quartz syenite, according to the state’s online geologic map. They have pieces of it at the tasting tables! Check it out:

Not only that, but there’s a neat display downstairs showing the core that was drilled into the hill:

This plutonic rock crystallized during the Neoproterozoic, about 722 (±3) million years ago. It’s part of the Robertson River Igneous Suite, a collection of a dozen or so plutons* of “anorogenic granites” that were emplaced during the first phase of the breakup of the supercontinent Rodinia, and the opening of the Iapetus Ocean.

* Some members of the RRIS are volcanic, it should be noted.

We toured the winery, and admired their classic barrels of French oak…