basalls

Basalls are a type of sedimentary rock formed from the accumulation and cementation of basalt fragments. These fragments, known as basaltic clasts, can vary in size from fine ash to larger pebbles and cobbles. The origin of these fragments is typically volcanic activity, where lava flows or explosive eruptions break down basaltic rock.

The composition of basalls is primarily basaltic minerals such as plagioclase feldspar, pyroxene, and olivine. However, the presence of interstitial matrix material, which can be finer-grained volcanic debris or material derived from weathering and erosion, is also common. The color of basalls can range from dark gray to reddish-brown, depending on the degree of oxidation and the presence of other minerals.

Basalls are often found in association with volcanic regions or ancient lava flows. They can form in various depositional environments, including alluvial fans, river channels, or even shallow marine settings where volcanic material is transported and deposited. The rock's texture can be coarse and conglomerate-like if large clasts are abundant, or finer-grained if the fragments are predominantly ash-sized. Understanding basalls helps geologists interpret past volcanic and depositional histories of an area.