---
source: https://iinventedlight.com/library/notes/plate-tectonics.md
title: "Plate tectonics in plain terms"
license: CC-BY-4.0
license_url: https://creativecommons.org/licenses/by/4.0/
source_license: "US government work, public domain; restated in our own words"
attribution: "Summary by iinventedlight (AI-assisted). Sources: USGS, Historical perspective [This Dynamic Earth, USGS], US government work, public domain; USGS, Understanding plate motions [This Dynamic Earth, USGS], US government work, public domain."
author: "iinventedlight (synthesis of cited sources); text drafted with AI assistance"
date: 2026-11-04
status: published
checked_on: 2026-11-04
as_of: 2026-11-04
confidence: medium
untested: "No observation or experiment was done; only the fetched government pages were read."
category: coverage-gaps
topic_area: "science-explain: earth and ocean science"
tags: science, geology, plate-tectonics
sources:
  - id: S1
    title: "Historical perspective [This Dynamic Earth, USGS]"
    publisher: USGS
    url: https://pubs.usgs.gov/gip/dynamic/historical.html
    accessed: 2026-11-04
    license: "US government work, public domain"
  - id: S2
    title: "Understanding plate motions [This Dynamic Earth, USGS]"
    publisher: USGS
    url: https://pubs.usgs.gov/gip/dynamic/understanding.html
    accessed: 2026-11-04
    license: "US government work, public domain"
---
# Plate tectonics in plain terms

## Short answer
Plate tectonics is the idea that Earth's outer layer is broken into a dozen or more rigid slabs of rock (plates) that slowly move relative to one another. A "plate" is a large, rigid slab of solid rock, and "tectonics" comes from a Greek root meaning "to build". [S1]

## Where plates meet
Most of the action, including earthquakes, happens along narrow zones between plates. The main types of boundaries are: [S2]
- **Divergent:** plates move apart and new crust forms.
- **Convergent:** one plate dives under another and crust is destroyed.
- **Transform:** plates slide past each other horizontally.

## Claims
- id: C1
  claim: A plate is a large, rigid slab of solid rock.
  source: S1
  evidence: "a plate is a large, rigid slab of solid rock."
- id: C2
  claim: Tectonics comes from the Greek root to build.
  source: S1
  evidence: "The word tectonics comes from the Greek root"
- id: C3
  claim: There are four types of plate boundaries in the USGS scheme.
  source: S2
  evidence: "There are four types of plate boundaries:"
- id: C4
  claim: At divergent boundaries new crust is generated.
  source: S2
  evidence: "Divergent boundaries -- where new crust is generated as the plates"

## Sources
- [S1] Historical perspective [This Dynamic Earth, USGS]. USGS. https://pubs.usgs.gov/gip/dynamic/historical.html . License: US government work, public domain. Accessed 2026-11-04.
- [S2] Understanding plate motions [This Dynamic Earth, USGS]. USGS. https://pubs.usgs.gov/gip/dynamic/understanding.html . License: US government work, public domain. Accessed 2026-11-04.

License: this note is CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Summary by iinventedlight (AI-assisted).