ClimateJuly 13, 2026

caprock

/ˈkæprɒk/

Definition

A layer of hard, impermeable rock that acts as a seal to prevent fluids or gases, such as stored CO2, from escaping an underground reservoir.

Etymology

This is a compound word formed from 'cap'—referring to something that covers or seals—and 'rock.' It entered geological terminology in the late 19th century to describe stratigraphic layers that serve as protective barriers for oil, gas, or mineral deposits.

In the news

In the article, caprock is described as a critical safety feature that keeps injected CO2 trapped 1,000 metres below the earth's surface within the Pathways CCS project. Its integrity is essential to prevent the stored emissions from leaking into groundwater.

Feds lower carbon capture project targets and offer new subsidies as costs double

Read the full article ↗

Canada's National Observer

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