intraformational conglomerate

Intraformational conglomerates are sedimentary rocks composed of rounded fragments larger than 2 millimeters in diameter. These fragments are derived from within the same depositional basin, meaning they were eroded and redeposited locally. This contrasts with extraformational conglomerates, where fragments originate from outside the basin.12

Intraformational conglomerates often form thin bands within shallow marine or nonmarine deposits. They are typically created by brief, strong currents that rip up recently settled sediment. For instance, storm waves can erode and redeposit carbonate mud layers, forming limestone conglomerates. Similarly, high-velocity river currents can create shale pebble conglomerates within floodplain deposits. These rocks are volumetrically less significant than other sedimentary types but are widespread in the geologic record.2