Is greywacke a metamorphic rock?
GeologyGraywacke sandstone is a sedimentary rock that is made up mosttly of sand-size grains that were rapidly deposited very near the source rock grom which they were weathered. What type of rock is greywacke? Graywacke sandstone is a sedimentary rock that is made up mostly of sand-size grains that were rapidly deposited very near the
Who is the most famous seismologist?
GeologyCharles F. Richter, in full Charles Francis Richter, (born April 26, 1900, near Hamilton, Ohio, U.S.—died September 30, 1985, Pasadena, California), American physicist and seismologist who developed the Richter scale for measuring earthquake magnitude. Who is the best seismologist in the world? WILLIAM ELLSWORTH, professor of geophysics at Stanford Earth, has won the Seismological Society
How was the North American continent formed?
GeologyThe continental fragments constituting interior North America coalesced between about 2.0 and 1.8 billion years ago. The amalgamation began about 1.97 billion years ago, when the Slave province collided obliquely with the western Churchill province. Where is the North American Craton? One of those original continents is the North American craton, located mostly in the
What do you do in a earthquake warehouse?
Geology and GeographyIf you are inside of a warehouse during an earthquake, quickly move to a safe place that is free of falling hazards. Crouch under a sturdy piece of furniture or cover your head with your arms, and stay put until the shaking stops. Stay away from any light fixtures that can fall and stay inside
Where does abrasion occur?
Geology and GeographyAbrasion occurs when rocks and stones become embedded in the base and sides of the glacier. These are then rubbed against the bedrock (at the bottom of the glacier) and rock faces (at the sides of the glacier) as the glacier moves. How does abrasion occur in nature? In nature, abrasion occurs as wind and
How much of Earth’s history took place during the Precambrian eon?
Geology90%almost 90% of the entire history of the Earth. It has been divided into three eras: the Hadean, the Archean and the Proterozoic. The Precambrian Era comprises all of geologic time prior to 600 million years ago. What percent of Earth’s history is Precambrian? 88 percent Precambrian (Informal—4.6 billion years ago to 541 million years
What is block cave mining?
GeologyTouted as the deep mining method of the future, block caving is an underground mass-mining method that allows for the bulk extraction of large, relatively lower-grade ore deposits that are vertical in orientation. What does block caving mean? Definition of block-caving : a mining in which sections of a large ore body are undercut by
What are the time divisions that are used for the geologic time scale and what determines how they are divided?
GeologyIn the Geologic Time Scale, time is generally divided on the basis of the earth’s biotic composition, with the Phanerozoic Eon (i.e. the Paleozoic, Mesozoic and Cenozoic Eras) representing the period of Earth’s history with advanced life forms, and the Pre Cambrian (or Proterozoic and Hadean Eras) representing the … What are the divisions of
What is mafic magma?
GeologyDescribes magma that contains lower amounts of silica and is generally less viscous and less gas-rich than silicic magma. Tends to erupt effusively, as lava flows. Includes andesites (57-63 percent SiO2), basaltic andesites (53-57 percent SiO2), and basalts (47-53 percent SiO2). What are the characteristics of mafic magma? Mafic magmas are low in silica and
Can you really dig to China?
GeologyYou can technically dig through the Earth to get to China, but it’s more challenging than it sounds. If you want to dig to China, you’d actually need to start your journey in Chile or Argentina — not the US. Can you dig straight down to China? To dig to China, you’d need to start