Earth's Origin and Structure
Earth's outer rocky layer, which consists of the crust and rigid upper mantle.
What is the lithosphere?
Wegener's hypothesis that Earth's continents formed when a single landmass fragmented.
What is continental drift?
Tendency of a mineral to break along smooth, flat surfaces.
What is cleavage?
Rock texture characterized by mineral grains cemented together.
What is clastic texture?
Style of eruption characteristic of lavas that have released their volatiles during ascent.
What is an effusive eruption?
13.8 billion years based on astronomical measurements.
What is the age of the Universe?
This force is thought to be the most important driver of plate motion.
What is slab pull?
Family of minerals that comprise most of Earth's crust and mantle.
What are the silicates?
This process leads to the melting of mantle rock directly above a sinking oceanic plate.
What is addition of volatiles?
Dense suspension of hot rock fragments in gas and superheated air.
What is a pyroclastic flow?
Iterative technique for understanding Nature based on observations and hypothesis testing.
What is the scientific method?
Deep narrow seafloor features that mark the locations of subduction zones.
What are trenches?
Naturally occurring solids with fixed chemical compositions and crystalline structures.
What are minerals?
Texture that characterizes igneous rocks formed as magma cools slowly underground.
What is coarse grained texture.
Small volcano formed by hot, soft globs of mafic lava thrown a few meters to tens of meters from a vent.
What is a spatter cone?
This soft layer of the upper mantle flows readily to allow plate motion.
What is the asthenosphere?
Linear structures that offset oceanic ridges and enable opposing plates to slide sideways past one another.
What are oceanic transform faults?
Bond between two elements with moderate numbers of electrons (3-5) in their outer shells.
What is a covalent bond?
Sheet like intrusion that cuts across the structure of surrounding rocks.
What is a dike?
Likely activity level of a volcano that has not erupted for tens of thousands of years and is deeply eroded.
What is extinct?
The inner terrestrial planets consist primarily of these two materials.
What are silicate rock and iron metal.
Places, like Hawai`i, where volcanism marks the top of a mantle plume.
What are hotspots?
Earth material that can be mined and processed to yield a metal profitably.
What is an ore?
Process that changes a magma's composition when it ingests and dissolves wallrock fragments.
What is assimilation?
Earthquakes, heat flow, ground deformation, and gas emission may all provide this time scale of warning.
What is a short term warning?