Diatomaceous Silica in Environmental Applications: A Case Study from the Lacustrine Deposit of Limnos Island, Aegean Sea, Greece

Diatomitic and clastic-volcanoclastic marly samples from the Paranisia area of Limnos Island, were studied mineralogically by X-ray diffraction (XRD), chemically by X-ray fluorescence spectroscopy (XRF) and morphologically by scanning electron microscopy (SEM-EDS), together with some physical properties such as the insulation block density, specific surface area and porosity. The diatomaceous samples were classified as porcelaneous or clayey (moler type) diatomite. Opal-CT forms microplates disseminated in the groundmass and are diagenetically formed in expense of opal-A dissolution. The purest diatomaceous beds have been transformed into opaline beds (opal-CT-rich rocks), whereas the clayey beds were not influenced by diagenetic transformations. The studied diatomites from Limnos Island are suitable materials for environmental uses, as an absorbent, for the production of insulation bricks or as lightweight aggregates.