how were lake superior agates formed?
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Lake Superior Agates are a specific kind of stone that was formed by volcanic activity along the North Shore 1.2 billion years ago. Gas pockets in the molten lava filled with mineral deposits like ferric iron, quartz or calcite as the years passed by.
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['Small pieces of rock are transported by a river.', 'Pieces of rock are deposited and layers of sediment build up.', 'Sediments are compacted and water is squeezed out. Crystals form, which cement the pieces of rock together.']
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Translucent agates of many colors are found along Kenai Peninsula beaches with patience and luck (credit: Donna Brewer). Almost everyone I know likes to search for agates along our Cook Inlet beaches.
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Agate /ˈæɡət/ is a common rock formation, consisting of chalcedony and quartz as its primary components, consisting of a wide variety of colors. Agates are primarily formed within volcanic and metamorphic rocks.
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Niagara Falls was formed starting more than 12,000 years ago at the end of the Ice Age when large torrents of water were released from the melting ice, draining into the Niagara River. The water plunged over the edge of the Niagara Escarpment – to what is now known as Lewiston, NY.
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Amphibolite is a non-foliated metamorphic rock that forms through recrystallization under conditions of high viscosity and directed pressure. It is composed primarily of hornblende (amphibole) and plagioclase, usually with very little quartz.
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A bog is formed when a lake slowly fills with plant debris. Sphagnum moss, as well as other plants, grow out from the lake's edge. The vegetation eventually covers the lake's entire surface. Bogs can also form when the sphagnum moss covers dry land and prevents precipitation from evaporating.
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Stalactites and stalagmites are formed by chemical weathering. Water dissolves the calcites in the rock of a cave roof and the calcite is deposited as strange and wonderful structures below.
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['Sills: form when magma intrudes between the rock layers, forming a horizontal or gently-dipping sheet of igneous rock. ... ', 'Dykes: form as magma pushes up towards the surface through cracks in the rock. ... ', 'Batholiths:']
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After that average minimum price, the price is between one dollar to five dollars for each pound of agate. Keeping this in mind, the price for the best of the best Lake Superior agates can be up to one thousand dollars per pound.
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“The fjords were created by massive glaciation that went below sea level”, he continues. “Over a period of 2.5 million years, the U-shaped valleys were carved out of the ground during a succession of glacial cycles. In other words, the fjords were shaped by the glaciers.”
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The Salt Flats were formed when ancient lake Lake Bonneville dried up. The lake was huge, filling much of the Great Basin. It eventually shrank below its outlet and so its water became salty. As water continued to evaporate, salt deposits were left in many areas.
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The lava flows formed the conditions for creation of Lake Superior agates. As the lava solidified, water vapor and carbon dioxide trapped within the solidified flows formed a vesicular texture (literally millions of small bubbles).
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Gneiss is formed by high temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. ... Gneiss nearly always shows a banded texture characterized by alternating darker and lighter colored bands and without a distinct foliation.
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A COMMON ROCK IN RARE FORM As the calcium comes in contact with carbonates in the lake, a chemical reaction occurs resulting in calcium carbonate--limestone. The calcium carbonate precipitates (settles out of solution as a solid) around the spring, and over the course of decades to centuries, a tufa tower will grow.
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Black agate is a form of chalcedony which is a form of Quartz crystal. When you hold this stone and look at it, it will look like solid rock but when you hold it up to the light, you will notice that it's actually translucent.
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The lakes are continuously changing colour according to the amount of minerals or organisms, as well as the angle of sunlight. The most important ingredient causing the water to turn blue or green is calcium carbonate from limestone rocks.