They are marked by eruptions of cooler, stickier lavas such as andesite, dacite and rhyolite. |
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The volcanic strata consist of sheet-like flows of andesite, dacite, basalts, and trachybasalts that are interbedded with agglomerates and tuffs. |
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Both the sandstone and andesite show strong quartz and chert veining and carry disseminated pyrite. |
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Made from a single slab of andesite weighing at least 10 tons, this monolith is carved in the form of a doorway with niches on either side. |
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The fault places massive fractured greenstones over relatively undeformed feldspar andesite porphyry. |
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Peck used locally quarried andesite, a brittle stone that fractures into sharp, angular shapes and has a sparkly surface. |
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Nevado del Ruiz volcano is an andesite stratovolcano located in the northern Andes of Colombia. |
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Some rocks have basaltic compositions similar to the well-studied meteorites thought to have come from Mars, but other rocks are more like the volcanic rock andesite. |
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Small lithic fragments comprise quartzite, gneiss and ubiquitous andesite. |
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The volcanic necks are composed of basic rocks, basalt, basalt breccia, or andesite, showing considerable variation in mineralogy, texture, and structure within the same neck. |
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Above the Bleng are large areas of diorite, while around Buckbarrow there are outcrops of the andesite Birker Fell Formation. |
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The summit area is composed of flow banded andesite lavas, the Haystacks Member. |
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The fell is dominantly composed of composite andesite lava flows, with autobrecciated upper surfaces developed in some locations. |
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Intermediate lavas form andesite domes and block lavas, and may occur on steep composite volcanoes, such as in the Andes. |
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The Cheviot Hills, in the northwest of the county, consist mainly of resistant Devonian granite and andesite lava. |
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Vent facies on the north and eastern sides of Fish Lake are mostly flows and breccias of andesite and rhyodacite. |
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Two main geological units have been identified at Charay, an upper volcaniclastic unit and a lower andesite flow unit. |
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Granite, basalt, andesite and trachyte are used as coating materials for buildings. |
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The centre of the range comprises a Devonian granite outcrop surrounded by Silurian and Devonian andesite lava flows on each side. |
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Later basaltic andesite and rhyolite are considered to be coeval with pluton emplacement as all units are dated at ca. |
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Mineralization is hosted by Late Cretaceous andesite intruded by porphyry stocks and dikes. |
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Fine art experts say the one-ton andesite carving comes from Indonesia and was formerly part of a German collection. |
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The summit dome itself, together with the steep northern cliffs, are composed of andesite and basaltic lavas. |
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Hydrous magmas composed of basalt and andesite are produced directly and indirectly as results of dehydration during the subduction process. |
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Continental islands lie outside the andesite line and include New Guinea, the islands of New Zealand, and the Philippines. |
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The andesite line is the most significant regional distinction in the Pacific. |
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Indonesia, the Philippines, Japan, New Guinea, and New Zealand lie outside the andesite line. |
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Outside the andesite line, volcanism is of the explosive type, and the Pacific Ring of Fire is the world's foremost belt of explosive volcanism. |
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The continental crust consists of lower density material such as the igneous rocks granite and andesite. |
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The most common rocks in West Antarctica are andesite and rhyolite volcanics formed during the Jurassic period. |
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The rock in the valley is generally Borrowdale tuff and rhyolite with andesite sills with areas of slate, particularly to the south. |
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The average depth of oxidization is 25 m and the gold mineralization is hosted in a broad zone of metasomatically altered andesite. |
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The Mamay area is underlain by a series of metasomatically altered sediments and andesite intruded by granite and granodiorite. |
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The texture of andesite is generally porphyritic, with phenocrysts of feldspar and ferromagnesian minerals. |
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The gold mineralization is hosted in metasomatically altered dacite and andesite and is interpreted to be controlled by the northeast trending Aksuyski fault zone. |
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In some way, not clearly understood, hydrothermal action metasomatizes the original andesite without destroying original textures or changing volumes. |
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Within the closed loop of the andesite line are most of the deep troughs, submerged volcanic mountains, and oceanic volcanic islands that characterize the Pacific basin. |
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Nearer the summit are intrusions rhyolite and sills of basaltic andesite. |
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Bands of volcaniclastic sandstone and andesite sills are also present. |
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Pillow lavas are commonly of basaltic composition, although pillows formed of komatiite, picrite, boninite, basaltic andesite, andesite, dacite or even rhyolite are known. |
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Below these distinctive rock units the andesite lava flows are seen again. |
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Laminated volcaniclastic claystones and siltstones of the Esk Pike Formation form the upper reaches, crossed by an intrusion of andesite and hybridized andesite porphyry. |
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The predominant rocks on Bowfell are the volcaniclastic sandstones of the Seathwaite Fell Formation, with interbeds of andesite outcropping near the summit. |
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