1. sedimentary rocks formed from consolidated mud or clay, typically fine-grained and composed of silt and clay minerals
Usage: geology; plural form; singular is mudrock; includes shales, siltstones, and claystones

Examples

• Mudrocks make up a significant portion of the Earth's sedimentary crust.
• The geologist examined the mudrocks to determine the depositional environment of the ancient lake.
• Shales are the most common type of mudrocks found in sedimentary sequences.
• Mudrocks often contain fossils because they form in quiet water environments.
• The drilling core revealed alternating layers of sandstones and mudrocks.
• Mudrocks have low permeability, making them useful as seals in petroleum systems.