Mineralogical and geochemical characteristics of Quaternary sediments from the Island of Susak (Northern Adriatic, Croatia) Snje zana Mikul ci c Pavlakovi c a, * , Marta Crnjakovi c a , Darko Tiblja s b , Marin Soufek a , Lara Wacha c, d , Manfred Frechen d , Damir Lackovi c a a Croatian Natural History Museum, Department of Mineralogy and Petrography, Demetrova 1, HR-10 000 Zagreb, Croatia b University of Zagreb, Faculty of Science, Horvatovac 95, HR-10 000 Zagreb, Croatia c Croatian Geological Survey, Sachsova 2, HR-10 000 Zagreb, Croatia d Leibniz Institute for Applied Geophysics (LIAG), S3: Geochronology and Isotope Hydrology, Stilleweg 2, D-30655 Hannover, Germany article info Article history: Available online 13 February 2010 abstract Middle and Upper Pleistocene loessepalaeosol sequences up to 90 m thick are exposed on the Island of Susak located in the Northern Adriatic Sea in Croatia. During glacial times the sea level was up to about 120 m lower and a significant part of the Adriatic became land. The source area of the primary aeolian sediments was in the vicinity of the island and is related to the southward extended River Po plain. The loess has a mainly clayey to sandy silt or sand grain-size and is intercalated by at least three tephras, numerous palaeosols and calcareous segregations. The heavy mineral association points to metamorphic and igneous rocks from Alpine regions as source material of the loess. Geochemical and mineralogical properties of loess and palaeosols differentiate one from another and reflect the intensity of weathering and pedogenesis. The oldest tephra contains vitroclasts and serrated clinopyroxene while the middle and the youngest tephra along with vitroclasts, contain idiomorphic augite as diagnostic volcanic features. Based on bulk rock and vitroclast chemistry, morphology of pyroxenes, and the age of the loess sand- wiching the tephra, the potential source of this volcanic material could very likely be the Campanian or Aeolian volcanic province in southern Italy. Infrared stimulated luminescence dating-results show that the major part of the aeolian deposits including the tephra layers correlates to MIS 3eMIS 5. Ó 2010 Elsevier Ltd and INQUA. All rights reserved. 1. Introduction Quaternary aeolian deposits are widely distributed on Adriatic islands and along the Croatian and Italian coasts. In the Kvarner region, aeolian sediments including loess, its derivatives and sand have been found on the islands of Unije, Vele and Male Srakane and Losinj. The most impressive and thickest loessepalaeosol sequence is exposed on the Island of Susak. Susak Island is situated in the western part of the Kvarner archipelago (Fig. 1) and covers an area of 3.8 km 2 with the highest peak at 96 m above sea level (asl). The landform is characterized by specific loess plateaus, and steep, mostly inapproachable loess bluffs and gorges covered by vegetation. Two sandy beaches are located along Susak Bay near to Susak harbour and along Bok Bay (Fig. 2). Most of the bedrock is made of Senonian rudist limestone and CenomanianeTuronian limestone in the southeast part and northwest part of the island, respectively. On the northern coast, Eocene limestone is found in a narrow zone between two faults (Mamuzic, 1973). Geotectonically, Susak and the southwestern part of Unije Island are part of the Istrian autochton of the Northern Adriatic platform (Bognar et al., 2003). Susak loess deposits provide a very detailed record of climate and environment change and are one of the most impressive geomorphological phenomena on the Adriatic islands. According to Bognar et al. (2003) they are thickest in the northwest part of the Island (up to 90 m in Garba area, Fig. 2). However, deposits of the lower southeast part, being more accessible, have been the subject of most previous studies. Stache (1872), Marchesetti (1882), Salmojraghi (1907), Kispatic (1910), Sandor (1912), Mutic (1967), Bognar et al. (1983) and Cremaschi (1990b) investigated prove- nance and mineral composition of loess. Based on the heavy mineral association, which is typical for metamorphic rocks of Alpine regions, most of the previous researches concluded that the source area of the aeolian sediments from Susak is the ancient alluvial plain formed by River Po and today submerged by the Adriatic Sea. These sediments were most likely accumulated by fluvial and aeolian transport mechanisms during the glacio-eustatic regression in Middle and Late Pleistocene. Markovic-Marjanovic (1966), Wein * Corresponding author. Tel.: þ385 1 4851 700; fax: þ385 1 4851 644. E-mail address: snjezana.mikulcic@hpm.hr (S. Mikulcic Pavlakovic). Contents lists available at ScienceDirect Quaternary International journal homepage: www.elsevier.com/locate/quaint 1040-6182/$ e see front matter Ó 2010 Elsevier Ltd and INQUA. All rights reserved. doi:10.1016/j.quaint.2010.02.005 Quaternary International 234 (2011) 32e49