Sediment geochemistry and mineralogy in Milos bay, SW Kyklades, Aegean Sea, Greece

• Published in: Journal of marine systems Vol. 16; no. 3; pp. 269 - 281
• Main Authors: Karageorgis, A., Anagnostou, Ch, Sioulas, A., Chronis, G., Papathanassiou, E.
• Format: Journal Article
• Language: English
• Published: London Elsevier B.V 01.10.1998; Elsevier
• Subjects: Aegean Sea; Earth sciences; Earth, ocean, space; Exact sciences and technology; Geochemistry; heavy metals; Metal geology; Metallic and non-metallic deposits; Milos island; sediment; Soil and rock geochemistry; Cyclades; Greece; East Mediterranean; Southern Europe; Greek Aegean Islands; Aegean Sea; Milos; MED, Greece, Kyklades, Milos Bay; Aegean Sea; heavy metals; sediment; Milos island; bathymetric maps; Europe; X-ray diffraction; carbonates; spatial distribution; lead; grain size; X-ray fluorescence; sheet silicates; silicates; clay minerals; statistical analysis; Mediterranean Sea; correlation coefficient; zinc; marine sediments
• ISSN: 0924-7963; 1879-1573
• DOI: 10.1016/S0924-7963(97)00020-1

This work aims at studying the geochemistry and mineralogy of Milos bay surface sediments. The bay forms an enclosed marine area, supplied totally by volcanic formations. Totally 16 samples were subjected to sedimentological (grain size), mineralogical (microscope examination and X-ray diffraction of the bulk sample and the pelitic fraction), and geochemical analyses (X-ray fluorescence in the pelitic fraction). Also the carbonate content was determined. Sediments were sandy with a high carbonate content (14–58%). The dominant minerals recognized in the pelitic fraction were smectite, kaolinite and illite, followed by chlorite, quartz, calcite, Mg-calcite and feldspars. In general, element concentrations appeared to be within the normal range, except Pb and Zn, which exhibited relatively high values. The Index of Geoaccumulation I geo was computed, in order to investigate a possible enrichment of the surface sediments in metals. The analysis revealed again high values of I geo class for both Pb and Zn. A careful study of the area, in relation to the quality of the catchment basins petrology, lead to a non-anthropogenic origin of these high concentrations. The enrichment of the surface sediments in Pb and Zn is attributed to the weathering of several mineral deposits, pyroclastic rocks and lavas, covering almost all Milos vicinity. A study of the geochemical data correlation coefficient matrix revealed three major groups of elements: (i) the elements of detrital origin represented by Si, Al, K and a part of the metals; (ii) the carbonates group; and (iii) a Fe–Mn oxyhydroxides–oxides group, which attracts a part of Pb, Cr and Ni.