rubble

geology

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July 13, 2026

Quick Summary

Rubble refers to broken fragments, typically of rock or destroyed buildings, or a confused mass of worthless things. It can also describe rough, broken stones used in masonry or as quarried material.1

In geology, rubble is a key component of certain sedimentary rocks. Breccias are consolidated rubble with angular fragments, while conglomerates are consolidated gravel with rounded fragments. These rocks are formed when coarse fragments of pre-existing rocks are cemented together or held by a finer-grained matrix. Matrix-supported conglomerates, also known as diamictites, have coarse clasts suspended in a finer matrix and can be formed by processes like submarine landslides or glacial ice deposition.2

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sedimentary rock
Conglomerates and breccias
Breccias are consolidated rubble; their clasts are angular or subangular. Conglomerates are consolidated gravel whose clasts are subrounded to rounded. Sometimes the term rudite (or rudaceous) is used to collectively refer to both breccias and conglomerates.
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Breccias are consolidated rubble; their clasts are angular or subangular. Conglomerates are consolidated gravel whose clasts are subrounded to rounded. Sometimes the term rudite (or rudaceous) is used to collectively refer to both breccias and conglomerates.
Read More