Seabed and Surface Sediment Map of the Kvarner Region, Adriatic Sea, Croatia (Lithological Map, 1:500,000)

Abstract

A lithological map of recent marine sediments and the seabed ofthe Kvarner region (Adriatic Sea, Croatia) is presented on a scale of1:500,000. The map was compiled from existing published andunpublished data. This is an area characterised by a number of islandslocated between the Istrian Peninsula and the Vinodol-Velebit coast.Water depths in channels between the islands reach up to 125 m,compared to depths of 40-50 m in the open waters of the adjacentnorthern Adriatic.Over most of the Kvarner area, muddy and sandy sediments coverthe seafloor. Mud (M) is found on the bottom in Rijeka Bay, thenorthern part of the Kvarner, in Kvarneriæ, and in the Vinodol andVelebit channels, whereas over the rest of the Kvarner region seafloorsandy mud (sM) prevails, with subordinate occurence of gravellymud (gM). Sandy sediments, i.e. muddy sands (mS) dominate in theSW part to the open Adriatic, and west of Rab Island, in the Pag andVelebit Channels.Previous investigations indicate that the fine grained particlesthat are found in deeper parts of Rijeka Bay, Kvarneriæ, and VinodolChannel are of recent origin, and are deposited at water depths belowthe wave base. Sources of these particles are local permanent andtemporary streams and the direct input from weathering processes,along with input by submarine springs (vrulje) near the coast. Thelarge areas of the bottom not covered with sediments, or covered withgravelly and sandy sediments are found above the wave base, i.e. inthe erosional wave zone. Coarse-grained material is lithic and/or biogenic.However, due to the very rapid Late glacial-Holocene transgression,when sea-level rose more than a hundred metres, coarse sandysediments are found below the recent wave base in the SW parttowards the open Adriatic, and west of Rab Island, in the Pag andVelebit Channels. Therefore the sediment distribution in the Kvarnerregion is only partly in dynamic equilibrium with modern hydrodynamicconditions.