Educational Geology: the Archean Rocks of Beartooth Pass. Some of Earth's Oldest Rocks!

Описание: In this Granite Paradise Show and Tell video, we look at various specimens of granites, granodiorites, gneisses, porphyritic rhyolites and basalts, and other interesting finds collected along US Highway 212, known also as the Beartooth Highway, and, more specifically, Beartooth Pass. Art, a longtime contributor to Granite Paradise, painstakingly stopped everywhere he could along the upper portion of the highway to collect a representative assortment of rock samples, which are the main subject of this video. The ones you see already on the sculpture were given to me several years ago, and now he and his wife brought me the remainder of the collection, which I will find a way to combine into a single larger display. These rocks were uplifted approximately 15,000 feet during the Laramide Orogeny, and include Archean basement rocks of granodiorites and granites which are over 2 billion years old, and within these are found isolated lenses of much older, extremely metamorphosed rocks that are said to be as much as 3.9 billion years old. More recently, about 1.8 billion years ago, magma intrusions fractured and pushed into these rocks, in the form of dikes and sills, from which many of our porphyritic specimens come. We also touch briefly on the Stillwater Complex, which is another large, ancient intrusion containing precious metals and other treasures sought after by miners.
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