What is porphyritic andesite?
GeologyDescription. Andesite-porphyry is a porphyry with andesitic chemism. The term “porphyry” is used for igneous rock composed of large, conspicuous crystals (phenocrysts) and a fine grained to glassy groundmass (matrix) in which the phenocrysts are embedded. How is porphyritic andesite formed? Porphyritic texture — andesite: This is an extrusive igneous rock. The magma from which
What is special about Basalt?
GeologyBasalt is a mafic extrusive rock, is the most widespread of all igneous rocks, and comprises more than 90% of all volcanic rocks. Because of its relatively low silica content, basalt lava has a comparatively low viscosity, and forms thin flows that can travel long distances. What makes basalt special? basalt, extrusive igneous (volcanic) rock
What did Harry Hess discover that helped Wegener prove the continental drift theory?
GeologyAlfred Wegener produced evidence in 1912 that the continents are in motion, but because he could not explain what forces could move them, geologists rejected his ideas. Almost 50 years later Harry Hess confirmed Wegener’s ideas by using the evidence of seafloor spreading to explain what moved continents. What did Harry Hess find as evidence
What are the causes of tsunamis?
GeologyTsunami are waves caused by sudden movement of the ocean surface due to earthquakes, landslides on the sea floor, land slumping into the ocean, large volcanic eruptions or meteorite impact in the ocean. What are the 5 causes of tsunami? Tsunamis are caused by violent seafloor movement associated with earthquakes, landslides, lava entering the sea,
What are the stages of rock folding?
GeologyWhen a rock is subjected to increasing stress it passes through 3 successive stages of deformation. Elastic Deformation — wherein the strain is reversible. Ductile Deformation — wherein the strain is irreversible. Fracture – irreversible strain wherein the material breaks. What is the process of rock folding? When two forces act towards each other from
What igneous rock does quartzite turn into?
GeologyQuartzite is a metamorphic rock, while quartz is an igneous rock that crystallizes from magma or precipiates around hydrothermal vents. Sandstone under pressure becomes quartz arenite and quartzite, but quartzite does not become quartz. The construction industry further complicates the matter. What does quartzite turn into? quartzite, sandstone that has been converted into a solid
What is the biggest earthquake in San Diego?
GeologyAn earthquake of magnitude 4.1 was recorded Sunday morning in northern San Diego County, the U.S. Geological Survey said. The quake, at 9:46 a.m., was centered in Palomar Mountain State Park, 18 miles northeast of Escondido and 3 miles from the Palomar Observatory. The area is near the Elsinore fault zone. When was the last
What are the top ten most dangerous volcanoes?
GeologyThe World’s Most Dangerous Volcanoes Mount St. Helens, Washington. … Mount Kilauea, Hawaii. The world’s most active volcanic mass, Kilauea is home to many frequent eruptions. … Mayon Volcano, The Philippines. … Redoubt Volcano, Alaska. … Mount Pinatubo, The Philippines. … Mount Agung, Bali. … Mount Fuji, Japan. … Popocatépetl, Mexico. What are the 5
What is the streak of olivine?
GeologyDiagnostic Features: Distinguished usually by its glassy luster, conchoidal fracture, green color, and granular nature.…Olivine Physical Properties. Chemical Classification Silicate Streak Colorless Luster Vitreous Diaphaneity Transparent to translucent Cleavage Poor cleavage, brittle with conchoidal fracture Does olivine have a streak? Diagnostic Features: Distinguished usually by its glassy luster, conchoidal fracture, green color, and granular nature.Olivine
How does a biochemical sedimentary rock form?
GeologyBiochemical sedimentary rocks are formed from shells and bodies of underwater organisms. The living organisms extract chemical components from the water and use them to build shells and other body parts. The components include aragonite, a mineral similar to and commonly replaced by calcite, and silica. How are biochemical sedimentary rocks made quizlet? How do