Lower Shoreface refers to the portion of the seafloor, and the

sedimentary depositional environment In geology, depositional environment or sedimentary environment describes the combination of physical, chemical, and biological processes associated with the deposition of a particular type of sediment and, therefore, the rock types that will be ...

, that lies below the everyday

wave base The wave base, in physical oceanography, is the maximum depth at which a water wave's passage causes significant water motion. At water depths deeper than the wave base, bottom sediments and the seafloor are no longer stirred by the wave motion a ...

. It is also used for the

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...

sedimentary structure Sedimentary structures include all kinds of features in sediments and sedimentary rocks, formed at the time of deposition. Sediments and sedimentary rocks are characterized by bedding, which occurs when layers of sediment, with different partic ...

rock formation A rock formation is an isolated, scenic, or spectacular surface rock outcrop. Rock formations are usually the result of weathering and erosion sculpting the existing rock. The term ''rock formation'' can also refer to specific sediment ...

s that were produced by this process in an earlier geologic era, such as the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

Period.

Process

The

is the maximum depth at which a water wave's passage causes significant water motion. In this portion of the coastal marine environment, only the larger waves produced during storms have the power to agitate the seafloor. Between storms, finer grained

sediments Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand a ...

accumulate on the seafloor, but during storms those sediments get suspended and moved around, resulting in a

form described as

hummocky cross-stratification Hummocky cross-stratification is a type of sedimentary structure found in sandstones. It is a form of cross-bedding usually formed by the action of large storms, such as hurricanes. It takes the form of a series of "smile"-like shapes, crosscut ...

References

{{Reflist Physical oceanography Sedimentology Sedimentary structures

Process

See also

References