EARTH SCIENCE Flashcards
AGE OF EARTH
4.543 billion years old
a collective layer of gas that envelopes the Earth.
Atmosphere
Earth’s four major spheres
Atmosphere
Hydrosphere
Biosphere
Geosphere
(1) It shields the Earth and its inhabitants from harmful ultraviolet (UV) radiation from the Sun;
(2) it maintains the warmth of the Earth’s surface; and
(3) it contains all of the essential gases needed to support life.
Atmosphere
refers to the bodies of water consisting of freely flowing bodies of water found on the surface of the Earth
Hydrosphere
refers to the narrow band on the Earth’s surface where all biological life resides.
Biosphere
This sphere covers nearly 71% of the Earth’s surface.
Hydrosphere
the largest out of all the spheres, extending from the surface of the Earth down to its center.
Geosphere
Layers of Earth Based on Compositional Differences
Crust
Mantle
Core
This is the thinnest and outermost layer of the Earth.
Crust
two types of crust
the continental and oceanic crust.
younger and denser type of crust.
oceanic crust.
comprises most of the Earth’s volume
Mantle
The boundary between the crust and mantle
Mohorovičić discontinuity
core begins at the mantle-core boundary
Gutenberg discontinuity
divided into the upper and lower mantle, separated by
Repetti discontinuity.
its composition comprises a Fe-Ni (iron and nickel) alloy.
Core
Layers of Earth Based on Physical Properties
Lithosphere
Asthenosphere
Mesosphere
Outer Core
Inner Core
thick and brittle layer comprising the entire crust and uppermost layer of the upper mantle.
Lithosphere
Contrary to popular belief, it is not a “sea of molten rock.” The upper mantle comprises an Mg- and Fe-rich rock called
peridotite.
mechanically weak layer consisting of the lower portion of the upper mantle, extending to 660 km.
Asthenosphere
-comprised of the lower mantle
-is much stronger and flows with more resistance. Because of the immense pressure from the overlying layers, the strength of this layer increases with depth.
Mesosphere
The dominant rock type in this layer (Mesosphere) is a silicate rock called
perovskite.
Layer the only one made out of liquid
Outer Core