GENERAL GEOLOGY

Detailed explanation-1: -As the river rushed into the wide valley, the sediment fanned out across a triangle-shaped area, creating an alluvial fan. An alluvial fan is a triangle-shaped deposit of gravel, sand, and even smaller pieces of sediment, such as silt. This sediment is called alluvium.

Detailed explanation-2: -An alluvial fan is a fan-shaped area where silt, sand, gravel, boulders, and woody debris are deposited by rivers and streams over a long period of time. Alluvial fans are created as flowing water interacts with mountains, hills, or steep canyon walls.

Detailed explanation-3: -’Alluvial fans’ are depositional landforms that occur where confined streams fed by mountain catchments emerge, often via a narrow feeder canyon, onto a low-relief plain.

Detailed explanation-4: -Alluvial fans are sites of deposition of immature angular gravel, sandstone and mud. When these sediments get cemented or lithified, they turn into, respectively breccia, arkose and shale.

Detailed explanation-5: -Alluvial deposits are usually most extensive in the lower part of a river’s course, forming floodplains and deltas, but they may form at any point where the river overflows its banks or where the flow of a river is checked.