RELATIONSHIP BETWEEN SPECIFIC SURFACE-AREA AND SOME CHEMICAL AND PHYSICAL-PROPERTIES OF PARTICULATES - STUDY IN THE NORTHERN ADRIATIC

Geochemical and sedimentological investigations of particulates (settling particles and sediments) in the northern Adriatic Sea show a direct relationship between the specific surface area (SSA) and their granulometric and mineralogical composition. Samples of suspended matter (settling particles), are collected using sediment traps, and contain large quantities of aluminosilicates. Their mean size varies between 3-10-mu-m, and SSA varies between 5-23 m2 g-1. Sediment samples vary in size between 3-180-mu-m, have a carbonate fraction between 2-50%, and SSA between 1-20 m2 g-1. The mineralogical composition and grain-size distribution are interrelated indicating that samples having more clay minerals are always fine grained. On the other hand, coarse sediments have more quartz and carbonates. The SSA is apparently dependent on grain size. However, laboratory investigations show that mineralogical composition is the most important factor, which governs the SSA of the inorganic core of particulates. Organic matter found in large concentrations in all studied samples (up to 16.5%) influences considerably the SSA. It usually contributes to the SSA of sediments, but decreases the SSA of suspended matter, probably by blocking the surface of the mineral core.