Detritus (geology)

In geology, detritus refers to loose particulate material produced by the disintegration of rocks. This material can be of mineral or organic origin. Detritus is transported by various agents such as water, wind, ice, and gravity, and it accumulates in layers or masses. The size of detrital particles can vary widely, ranging from microscopic clay particles to large boulders.

Detritus is a key component of sedimentary rocks. Over time, detrital sediments can be compacted and cemented together through lithification to form rocks like sandstone, shale, and conglomerate. The composition and characteristics of detritus provide valuable information about the source rocks, the transport pathways, and the depositional environment in which the sediment accumulated.

Detrital minerals are individual mineral grains that have been eroded from pre-existing rocks. Common detrital minerals include quartz, feldspar, mica, and various heavy minerals. The presence and abundance of specific detrital minerals can be used to determine the provenance (origin) of the sediment.

Detrital rocks are sedimentary rocks composed primarily of detritus. They are also known as clastic rocks. The classification of detrital rocks is based on the size of the detrital particles:

• Gravel: Particles larger than 2 mm (e.g., conglomerate, breccia)
• Sand: Particles between 0.0625 mm and 2 mm (e.g., sandstone)
• Silt: Particles between 0.0039 mm and 0.0625 mm (e.g., siltstone)
• Clay: Particles smaller than 0.0039 mm (e.g., shale, mudstone)

The study of detritus is crucial in various geological disciplines, including sedimentology, stratigraphy, and paleogeography. Analysis of detrital sediments helps geologists to reconstruct past environments, understand tectonic processes, and explore for natural resources such as oil and gas.