Santa Clara Valley Soil & Terrain
The Impact of Santa Clara Valley Soil & Terrain
The San Francisco Bay Area is a geologically active region with many fault lines. The local terrain is extremely diverse and the AVA has more soil types than some winemaking countries in Europe. The constant geologic shifts have created innumerable canyons and hills, each with specific microclimates.
Unfortunately, urban and suburban development has stifled the use of many of these areas for grape growing. But a handful of dedicated vintners persevere in this historic winemaking region.
The bedrock of Santa Clara Valley is made of the ancient Franciscan Complex. The Franciscan Complex is over 100 million years old and is made of oceanic crust. This soil rose to the surface in parts of California from the subduction of the Farallon Plate under the North American Continent.
The alluvial topsoil is made mainly of sandstone, but there is also some limestone. This is derived from hills to the south of the AVA. There is also some Salinian Granite in the ground, which originated in the Sierra Foothills 300 miles to the south. Point Reyes and the Farallon Islands are made almost entirely from this material.
The valley borders San Benito County, which contain the limestone-rich Gabilan Mountains. In general, the soils contain quite a bit of calcium and have a high pH; ideal for high quality grape growing.
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