Our Land
Southern Idaho—A lesson in Geology and Winemaking
Basking in the peaceful tranquility that is now Holesinsky Winery, it is hard to imagine the cataclysmic geological events that once took place here—events that spanned over hundreds of millions of years—and were necessary to create our perfectly blended loam soil.
It all started 600 million years ago, when the 40-mile-wide Beaverhead Asteroid plowed into southern Idaho, leaving a massive trove of mineral-rich, cosmic-born bounty in its wake.
Next followed 16 million years, and seven massive eruptions, of the Yellowstone volcanic caldera. As our tectonic plate glided slowly southwestward over the Yellowstone hotspot, southern Idaho was covered in layer after layer of rich, grape-quenching volcanic soil.
Finally, to mix it all up into the perfect loam blend, we can give thanks to the ice-age Bonneville Flood. 17,000 years ago, Lake Bonneville overflowed its banks, sending water at 33-million cubic-feet-per-second surging down the Snake River Canyon! The deluge finally slowed and settled right here in our valley, leaving behind the rich, perfectly blended, grape-nourishing soil that we enjoy today.
Southern Idaho’s unique geology is one of the reasons our wines are so special.
It is hard to believe that all these cataclysmic events in the past gave birth to something so beautiful now—the pure loam topsoil that Holesinsky Winery is blessed with.
Holesinsky Vineyard + Winery has been proudly producing organically grown grapes for the past 20+ years. Our vineyard is free of glysophates, chemicals and pesticides and we do not use any synthetic fertilizers, weed-killers or fungicides. We rely on Idaho’s unique soil composition and TLC to produce the beautiful grapes from which our wines are born.
Southern Idaho’s unique soil composition mixed with the creativity, care, and passions of the Holesinsky Family brings forward some of the most dazzling wines in the Northwestern United States.
Snake River Valley Geology
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Rhyolite
Rhyolite is an extrusive igneous rock with very high silica content. It is usually pink or gray in color with grains so small that they are difficult to observe without a hand lens. Rhyolite is made up of quartz, plagioclase, and sanidine, with minor amounts of hornblende and biotite. Trapped gases often produce cavities in the rock that often contain crystals, opal, or glassy materials.
Many Rhyolites form from granitic magma that has partially cooled in the subsurface. When these magmas erupt, a rock with two-grain sizes can form. The large crystals that formed beneath the surface are called phenocrysts, and the small crystals formed at the surface are called ground mass. Rhyolite usually forms in continental or continent-margin volcanic eruptions where granitic magma reaches the surface. Rhyolite is rarely produced in oceanic eruptions.
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Bassalt
Basalt is a dark colored, igneous rock composed mainly of plagioclase and pyroxene minerals. Basalt underlines more of the Earth’s surface than any other rock. Most areas within the Earth’s ocean basins are underlain by basalts. Most of the basalt found on Earth is produced in just three rock-forming environments: oceanic divergent boundaries, oceanic hotspots, and hotspots beneath continents. Another environment where basalt is formed is a continental environment. A mantle plume delivers enormous amounts of basaltic lava through the continental crust and up to the Earth’s surface. This method has produced the largest flow of basalt on land. Basalt is mostly used for construction projects. Basalt is also used for road base, concrete, and pavement. Basalt can also be polished for use as floor tiles.
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Breccia
Breccia rock formation is made of angular rock fragments randomly arranged and loosely cemented together in a yellowish matrix. There are many compositions of breccia. The composition is determined by the mineral material and rock that the angular fragments were produced from. This material ranges in size from boulders to sand grains. Angular boulders of breccia can be found along the canyon walls in various sizes directly above rhyolite, but its thickness varies. Breccia represents the break-up and erosion of the caldera possibly due to landslides. This rock occurs worldwide and has been found on the Moon and Mars. The rock is used as architectural stone for paving stones, building stones, tiles, windowsills, and interior building veneers.