Modern Cool-Water Carbonate Sediments in the Crete Island, Mediterranean Sea, Greece

Modern cool-water carbonate sediments have gained increased attention in the last 30 years, as they differ in many aspects from their tropical counterparts. Here we describe a mixed cool-water carbonate and siliciclastic system of the Crete Island in the Mediterranean Sea, being the largest (250 x 50 km) Greek island. The study is based on field observations and sampling of backshore, foreshore, and shoreface in 37 beaches along the entire island coast. All the beaches are developed in coves and embayments between rocky headlands, but they differ in morphometric parameters (width, indentation, slope or orientation to wind and waves). Most beaches are sandy with up to 25% of gravel that decreases in size and abundance from backshore to shoreface. Silt and mud are present in small amounts on most shorefaces. The sediments are composed in various proportions of skeletal fragments (mainly red algae and large benthic foraminifers, with minor bryozoans, bivalves, echinoids, and gastropods) and detrital grains (quartz and lithoclasts of magmatic, metamorphic, and sedimentary rocks). Benthic foraminifers are mainly warm-adapted, symbiont-bearing taxa with high-Mg porcelaneous (Peneroplis spp., Sorites spp.) and hyaline (Amphistegina spp.) walls. Superficial ooids were identified in one locality, suggesting local supersaturation in CaCO3. The carbonate fraction is a mix of fresh recent grains (white, shiny, unabraded) and relict grains (gray to yellow, dull, polished, some micritized and/or infilled with micrite), which is characteristic of many modern cool-water carbonate systems worldwide where grains are exposed on the seafloor for a long time due to low carbonate production.