Geology and Minerals
High Valley is an American Viticultural Area (AVA) located in the eastern part of Lake County, California adjacent to the eastern shoreline of Clear Lake. It was established as the nation's 163rd, the state's 92nd and county’s sixth appellation on July 1, 2005 by the Alcohol and Tobacco Tax and Trade Bureau (TTB), Treasury after reviewing the petition submitted by Kevin Robinson of the Brassfield Estate, on behalf of the High Valley AVA Committee, local vintners and growers, proposing a viticultural area in Lake County named “High Valley." ‘High Valley’’ is the officially recognized name of the elongated bowl-shaped valley encompassed by the viticultural area, as shown on the Clearlake Oaks, California, USGS Quadrangle map. True to its name, the valley is situated on higher elevations ranging from 1,600 feet (488 m) to 3,000 feet (914 m), but it actually encompasses two distinct growing regions, the valley floor and the hillsides. The valley itself is a 9-mile long (14 km) and 3-mile wide (5 km) landform, with an east–west orientation unusual in the California Coastal Range, a result of volcanic activity of Round Mountain, a dormant volcanic cinder cone at the eastern end of the valley. The AVA encompasses 15,000 acres (23 sq mi), and about 700 acres (280 ha) under vine. Most are relatively new, but within the area are some of the oldest vines in California. There are 15 struggling Zinfandel and Muscat vines planted by the Ogulin family, which brought them from Slovenia around 1875. Since Slovenia borders Croatia, where cousins of Zinfandel vines are found, this is significance in the history of California Zinfandel. The old vines were stables before Prohibition since Lake County was producing reputable wines before the vineyards were uprooted and replaced with other crops. Significant vineyards in the AVA include Brassfield Estate Winery, whose estate sits on the valley floor and Shannon Family of Wines. The plant hardiness zone ranges from 8b to 9b.
Calcite.
Cerro Azul (Ecuador volcano).
Text from Wikipedia; plate via Wikimedia Commons. Text CC BY-SA 4.0; plate freely licensed (see Commons). Source record. Images and catalogue data are reproduced from open-access collections.