Focus on Sedimentary Environments

A tropical carbonate beach

Bolongo Beach, St Thomas, US Virgin Islands


	Carbonate gravel on Bolongo Beach

Describing the sediment

Describe the beach sediment seen in the image above, using a standard description scheme. Make sure that you include in your description: grain size, sorting, and grain shape. Further information on these and other sediment properties.

Once you have written your description, check it by answering the questions below:

Identify the predominant grain size(s) in the lower part of the photograph (there may be more than one correct answer): boulders cobbles pebbles granules very coarse sand coarse sand medium sand fine sand very fine sand silt and clay	Describe the sorting seen in the sample: very well sorted well sorted moderately well sorted moderately sorted poorly sorted very poorly sorted
Identify the dominant grain shape(s): equant (cubic or spherical) oblate (disc-shaped) bladed prolate (rod or roller shaped)	How would you describe the rounding of this sample (more than one answer may be correct)? very angular angular subangular subrounded rounded well rounded