engleski

The provenance of sands on north Dalmatian beaches: between ignorance and the need for coastal zone management

The sand beaches of the Dalmatian coast represent an important natural resource of Croatia, but information is lacking about beach nourishment by sand. Our purpose was to obtain primary data about the sources of sand now building the beaches. These initial data can serve as part of a future data base for deciphering the transport paths of sand, thus leading to proposals for the best projects to protect the beaches. Both, beach sands and the ancient rocks representing possible sources for sand have been sampled. Samples of beach sand have been taken from the foreshore zone of seven beaches in northern Dalmatia. After the dissolution of carbonates, we have separated the heavy mineral fraction from the insoluble residue. Slides containing heavy mineral associations have been studied with a polarising microscope. Heavy mineral associations are highly dominated by garnet and ultrastable minerals. The comparison of the heavy mineral associations in beach sands and ancient rocks suggests that the sand of some beaches was derived predominantly or exclusively from Palaeogene rocks, and the sands of some other beaches reflect Pleistocene source rocks, while the rest of the beaches consist of sand derived from both sources. The results present a basic data set for seeking the transport paths of sand. This is indispensable for decision making concerning the use of the coastal zone.

sand; beach; provenance; heavy minerals; coastal zone management; Adriatic; Croatia

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