epiclastic conglomerate
Quick Summary
Epiclastic conglomerates are sedimentary rocks formed at the Earth's surface from fragments of pre-existing rocks. These rocks are typically composed of rounded fragments larger than 2 millimeters in diameter, distinguishing them from breccias, which have angular fragments.12
There are two main types of epiclastic conglomerates:
* Intraformational: Fragments are derived from within the same depositional basin.3
* Extraformational: Fragments originate from source rocks outside the depositional area.3
Extraformational conglomerates are further classified into:
* Clast-supported: Contain less than 15% matrix, with fragments touching each other. These are often deposited by turbulent water currents.4
* Matrix-supported (diamictites): Contain 15% or more matrix, with coarse clasts "floating" within finer material. These can be formed by processes like submarine landslides, turbidity flows, or glacial ice.3
Epiclastic conglomerates and breccias make up a small percentage of the overall sedimentary rock record.3
Ask Britannica AI about this topic
Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.
