Guyana’s flat coastal plain is interspersed with large shore-parallel lines of well-compacted inland sand dunes. These sand dunes are called ‘high sand reefs’ in the local vernacular as these reefs are above mean high tide level. It is believed that these reefs are of coastal origin forming from ancient beaches that were left behind when sea level fell in the geological past. Over years of human occupancy of Guyana’s coast, some reefs were used for habitation, agriculture, cemeteries and sand-extraction, while others were left to flourish with flora and fauna. Due to the paucity of studies on these reefs, this research aims to uncover some aspects of their origin and nature, to determine current and future uses as a coastal resource and to suggest ways for further investigation. Analyses were done on samples of materials collected from the sand reef located about 2 km inland of the Rose Hall Town-Port Mourant shoreline to ascertain their physical and chemical properties. Comparison was made with materials collected and analyzed from the tidal shore beaches in the area to compare with the sand reef materials. The sand reef material was found to have seashells and salinity and dissolved salts content similar to materials from the tidal beaches, indicating their coastal nature, though located on dry land 2 km behind the shoreline. Further research using radiometric dating could be done to determine the age of the reef sand and deep-core borings made to ascertain the soil profile of the reefs. This work attempts to add to the knowledge pool of Guyana’s coastal resources as the country moves into the petroleum-extraction industry.

Keywords : High sand reef; marine alluvium; salinity; pH; total dissolved solids; acidity-alkalinity.