pebbly mudstone

geology

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July 1, 2026

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Pebbly mudstone, also known as diamictite, is a type of sedimentary rock. It is characterized by a matrix of mud (silt and clay-sized particles) in which larger fragments, such as pebbles, cobbles, or boulders, are dispersed. These larger clasts "float" within the finer-grained matrix.1

Mudstone itself is a sedimentary rock primarily composed of clay or silt-sized particles. It is not laminated and can be blocky or massive in appearance. Pebbly mudstones are a specific type of mudrock and are not typically formed by normal water currents. Instead, they can be created by processes like submarine landslides, slumping, or glacial ice deposition (forming tillites).21

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sedimentary rock
Matrix-supported conglomerates
…rarer diamictites, known as laminated pebbly (or cobbly or bouldery) mudstones, consist of delicately laminated mudrocks in which scattered coarser clasts occur. Laminations within the muddy component are broken and bent. They are located beneath and adjacent to the larger clasts but gently overlap or arch over them, suggesting that…
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…rarer diamictites, known as laminated pebbly (or cobbly or bouldery) mudstones, consist of delicately laminated mudrocks in which scattered coarser clasts occur. Laminations within the muddy component are broken and bent. They are located beneath and adjacent to the larger clasts but gently overlap or arch over them, suggesting that…
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