Sedimentary characteristics of sand dune from Bang Berd, Chumphon Province, Southern Thailand

Abstract

The stratigraphy and sedimentary structures within Bang Berd dune field suggest a geological history that includes paleo-storm deposits. The goal of this project is to characterize the sand dunes in terms of their sedimentological features, including grain size distribution, internal sedimentary structures, wind direction indicators and documenting the evidence for paleo-storm deposits in this area. On aerial photographs, the dunes are aligned in NW and S-E wind directions.  Sand dunes here can be divided, on the basis of their geographic position and their morphological features into 3 units, outer dunes, middle dunes and inner dunes. Interestingly, sedimentary structures within the sand dune are very rare; only well developed inclined lamination can distinguish washover deposits from dune deposits. Both wind-blown and washover sands are very fine-grained, well to very well sorted and subrounded to rounded. The deposition of washover deposits that cover the outer dunes that is aligned in an almost east-west direction may indicate unusual paleo-storm pathways strike into the areas based on alternated washover deposits and dune sequence during 93+18 and 126+14 years ago.