Inputs of biogenic carbonate sediment from Posidonia oceanica seagrass meadows to four beaches of the Sinis peninsula (Sardinia, western Mediterranean) were evaluated. Beach and continental shelf sediment samples were analysed for grain size distribution and composition, biogenic vs. siliciclastic, in order to identify the provenance of beach sediments and sediment transport pathways. Seabed mapping was carried out in order to identify the distribution of meadows and sediment deposits offshore. Shelf sediments were collected in unvegetated sites and in P. oceanica meadows. Sediment from unvegetated sites were coarse sands and gravel, mainly siliciclastic (biogenic carbonate content is 3-7%). Sediments from P. oceanica meadows were coarse sand, mainly biogenic (carbonate contents varying between 60 and 90%). Beach sediments showed bimodal grain size distribution (59% of samples) resulting from mixing of coarser siliciclastic with finer biogenic materials in variable proportions. Biogenic carbonate contents in beach sediments range from 0 to 90%, reaching the highest values in offshore samples. Analysis of grain size and compositional trends from shelf to beach sediments highlighted that the latter originate from two different sources: erosion of granitic outcrops, providing the siliciclastic component, and export of sediments from P. oceanica meadows, providing biogenic material. P. oceanica meadows also influence shore dynamics by contributing towards maintaining the beach sediment budget.

Grain size and compositional trends of sediments Posidonia oceanica meadows to beach shore, Sardinia, western Mediterranean.

MOLINAROLI, Emanuela;BELLACICCO S.
2003-01-01

Abstract

Inputs of biogenic carbonate sediment from Posidonia oceanica seagrass meadows to four beaches of the Sinis peninsula (Sardinia, western Mediterranean) were evaluated. Beach and continental shelf sediment samples were analysed for grain size distribution and composition, biogenic vs. siliciclastic, in order to identify the provenance of beach sediments and sediment transport pathways. Seabed mapping was carried out in order to identify the distribution of meadows and sediment deposits offshore. Shelf sediments were collected in unvegetated sites and in P. oceanica meadows. Sediment from unvegetated sites were coarse sands and gravel, mainly siliciclastic (biogenic carbonate content is 3-7%). Sediments from P. oceanica meadows were coarse sand, mainly biogenic (carbonate contents varying between 60 and 90%). Beach sediments showed bimodal grain size distribution (59% of samples) resulting from mixing of coarser siliciclastic with finer biogenic materials in variable proportions. Biogenic carbonate contents in beach sediments range from 0 to 90%, reaching the highest values in offshore samples. Analysis of grain size and compositional trends from shelf to beach sediments highlighted that the latter originate from two different sources: erosion of granitic outcrops, providing the siliciclastic component, and export of sediments from P. oceanica meadows, providing biogenic material. P. oceanica meadows also influence shore dynamics by contributing towards maintaining the beach sediment budget.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in ARCA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10278/23974
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 81
  • ???jsp.display-item.citation.isi??? 73
social impact