Upper shoreface

Synonym

Inshore

Depth of water

Ebb tide - 6 - 7 meter depth (0 - 7 m)

Circumstances

Subjected to erosion and deposition by the strong influence of waves and currents. The seafloors are subjected to the influence of fair-weather waves. Longshore bars and longshore troughs almost parallel to the shores are formed by Longshore currents. Rip currents toward ocean side are at the gaps of Longshore bars. Inner bars of longshore bars move on foreshores to form berms during the fair-weather condition. The speed of movement is 2 - 11m per a day. Erosion of Longshore bars are dominant during storm-weather condition, and sands are carried to lower shoreface and inner shelf.

Sedimentary facies (Sediments)

Sands and gravels graded well.

Sedimentary facies (Structures)

Stacks of sediments of mega ripples. Wave ripples formed by waves. High angular trough and/or planar cross-stratification having 10 - 100 cm thick for a set. Sands and gravels of trough bottom sediments are at the basement of a set. Gravel dunes are formed during storm weather. Current directions may change as there are longshore currents and rip currents.