What are the four categories of magma?
Regional SpecificsBecause many of the properties of a magma (such as its viscosity and temperature) are observed to correlate with silica content, silicate magmas are divided into four chemical types based on silica content: felsic, intermediate, mafic, and ultramafic. What are 3 types of magma and what is their viscosity? Three general types are recognized: Basaltic
How do minerals form from hydrothermal solutions?
Regional SpecificsHydrothermal mineral deposits are accumulations of valuable minerals which formed from hot waters circulating in Earth’s crust through fractures. They eventually create metallic-rich fluids concentrated in a selected volume of rock, which become supersaturated and then precipitate ore minerals. How can hydrothermal solutions form new minerals? hydrothermal mineral deposit, any concentration of metallic minerals formed
Are all mountains fold mountains?
Regional SpecificsFold mountains are the most common type of mountain. The world’s largest mountain ranges are fold mountains. These ranges were formed over millions of years. Fold mountains are formed when two plates collide head on, and their edges crumbled, much the same way as a piece of paper folds when pushed together. Which mountains are
How did the Archean period end?
Regional SpecificsWhat happened at the end of the Archean eon? In the Archean Eon, oxygen-filled in the atmosphere, and most of the world’s iron ore was deposited. Because the Earth’s conditions stabilized, eukaryotic and multicellular life could finally emerge in the Proterozoic Eon. When did the Archean era began and end? Etymology and changes in classification
What are flute marks?
Regional SpecificsWhat is the flute mark? Typically, flute marks are bilaterally symmetrical heel-shaped hollows eroded into mud beds by debris-laden currents, acting either on prior defects on or within the bed, or on self-created defects, if the mud is insufficiently strong. Mud ripples closely resemble two-dimensional forms of current ripple. How do Flute marks form? Flute
What type of lava does Yellowstone have?
Regional SpecificsThe most likely type of volcanic eruption at Yellowstone would produce lava flows of either rhyolite or basalt. Does Yellowstone have basaltic lava? Basalt lava flows, though in lesser volume than rhyolites, have erupted throughout the 2.3 million-year volcanic history of the Yellowstone area. The magma feeding these eruptions originated in the upper part of