The key principle of plate tectonics is that the lithosphere exists as separate and distinct tectonic plates, which ride on the viscoelastic asthenosphere.

May 21, 2025 · In plate tectonics, Earth’s outermost layer, or lithosphere —made up of the crust and upper mantle—is broken into large rocky plates. These plates lie on top of a partially molten layer of …

Tectonic plates probably developed very early in the Earth's 4.6-billion-year history, and they have been drifting about on the surface ever since-like slow-moving bumper cars repeatedly clustering together …

Dec 11, 2025 · The concept of plate tectonics was formulated in the 1960s. According to the theory, Earth has a rigid outer layer, known as the lithosphere, which is typically about 100 km (60 miles) …

May 3, 2018 · The theory of plate tectonics is the unifying framework of modern geology. It explains how the Earth’s rigid outer shell — the lithosphere — is divided into large slabs called tectonic plates, …

Nov 8, 2024 · Plate tectonics is the theory that Earth’s outer shell is divided into several plates that glide over Earth's mantle.

Feb 10, 2024 · Tectonic plates are essentially rigid segments of the Earth’s lithosphere, a layer that includes the crust and the upper part of the mantle. They range in size from a few hundred to …

Sep 22, 2020 · Plate Tectonics and Our National Parks (2020) Text and Illustrations by Robert J. Lillie, Emeritus Professor of Geosciences, Oregon State University [E-mail] Produced under a Cooperative …

Plate Tectonics Theory Plate tectonics is the scientific understanding of how large, contiguous blocks of the Earth’s outermost layers—the crust and the uppermost mantle—move and interact with one …

Feb 17, 2023 · Tectonic plates are large, irregular-shaped slabs of rock making up the Earth’s crust and upper mantle. They are found to float on top of a semi-liquid layer of rock called the asthenosphere. …