Earth's Lithosphere Overview

Study Notes

The Earth's lithosphere is divided into layers based on physical and chemical properties.
The crust is the outermost layer, comprising less than 1% of Earth's mass, composed mainly of rock types such as granite and basalt.
The mantle, which makes up about 68% of Earth’s mass, is a mostly solid layer underneath the crust that flows slowly.
The outer core is a liquid layer around the inner core, primarily made of iron and nickel.
The inner core is a solid ball composed mainly of iron and nickel, with temperatures exceeding those of the Sun's surface.

Continental crust is thicker (between 6 to 47 miles) and less dense than oceanic crust, and is predominantly made of granite.
Oceanic crust is thinner and denser, primarily composed of basalt, and continuously recycles at plate boundaries.
Oceanic crust tends to be much younger than continental crust and sinks under it at plate boundaries, leading to geological events like earthquakes and volcanic eruptions.

The theory of plate tectonics explains that Earth's outer shell is divided into several plates that glide over the mantle.
Developed between the 1950s and 1970s, this theory evolved from Alfred Wegener's initial concept of continental drift proposed in 1912.
There are nine major tectonic plates: North American, Pacific, Eurasian, African, Indo-Australian, Australian, Indian, South American, and Antarctic.
The Pacific Plate is the largest, covering approximately 39,768,522 square miles (103,000,000 square kilometers), mostly underwater.

The lithosphere plays a crucial role in Earth's geological processes, including the movement of tectonic plates, resulting in earthquakes and volcanic activity.
Properties of the lithosphere, such as its rigidity and composition, influence its behavior and interactions with the underlying asthenosphere (the semi-fluid layer beneath the lithosphere).
Differences between oceanic and continental crust significantly impact geological events and help explain the mechanisms of plate tectonics.
The interaction between the oceanic and continental crust can trigger geological phenomena, including the formation of mountain ranges and ocean trenches.

"Geography" derives from Greek words "geo" (Earth) and "graphos" (to write), meaning a description of Earth.
Earth is the third planet from the Sun and the fifth largest in the solar system, recognized as the only known location with life-supporting environments.