The next Drunk on Geology is for Bedrock Old Vine Zinfandel by the Bedrock Wine Company.
The solid rock that underlies gravel, soil, or other superficial material.
|Geological Map of the Bedrock Vineyards locality. Map courtesy of the NGMDB.|
"From vines averaging over 80 years in age planted throughout the diverse state of California, this wine aims to reflect the perfume, freshness, and spice that makes Zinfandel so utterly delicious. Fermented with native yeasts and minimally racked, this wine should provide great short-term drinking but will age gracefully for 5-10 years."
"... a thick and highly variable series of continental volcanic rocks, including andesite, basalt, and minor rhyolite flows and interbedded coarse- to fine-grained pyroclastic tuff and breccia, redeposited tuff and pumice, and diatomaceous mud, silt, and sand."
So overall, it is likely the bedrock for the Bedrock Vineyard is the Glen Ellen Formation, however the Upper Petaluma Formation is also likely. These are likely sprinkled with local volcanic deposits from the Sonoma Volcanics as well.