engleski

Submerged Landscapes along the Coast of Croatia: Marine and Lacustrine Sediment Records of Environmental Change (LoLADRIA project)

The LoLADRIA project represents a multidisciplinary effort to recover, for the first time, long paleoenvironmental and paleoclimate records from existing coastal karst lakes and submerged karstic lakes of the eastern Adriatic shelf in Croatia. At glacial low sea levels large areas of the continental shelf were exposed, making them vailable to early humans. The project will attempt to reconstruct the specific karst lake landscapes and their surroundings in view of environmental and climate change and human migration from the Last Glacial Maximum (LGM) through the Holocene. Lakes and submerged karst depressions (lagoons) along the coastal region of Croatia are repositories of sediments which accumulated at various rates continuously during late Pleistocene and the Holocene, offering a rich and detailed archive of an environmental history. While terrestrial sequences in the Craoatian coastal karst regions are often incomplete due to erosion and nondeposition, lake and marine sediments offer complete and well-dated archives spanning throughout most of the Holocene. The LoLADRIA project is using cores (5-10 m long) collected from 17 sites (5 lacustrine and 12 marine) along eastern Adriatic coast. These sediments allowed multyproxy reconstructions of the Holocene millennial- and centennialscale environmental changes. A landscape reconstruction based on high resolution geophysical methods allowed insight to the preserved changes in marine sediments and submerged lake landscapes, in Lošinjski kanal, Novigradsko more, Karinsko more and Pirovački zaljev. The thickness of paleo-lake sediments varies from up to 2 m in Karinsko more to more 10 m in Lošinjski kanal. Details of environmental change are extracted for the by integrating mineralogy, lithostratigraphy biostratigraphy (pollen, foraminifers, ostracodes), tephrostratigraphy and chemical stratigraphy with a well defined 14C AMS radiocarbon chronologies. The study sites and the chronological spanning of the Holocene sediment sequences, gathered during the past five years, are presented to stress major environmental changes recorded during the Holocene. Intensive terrigenous fluxes are recorded in some cores by mineralogy, grain size distribution and major and minor element geochemistry, as well as pollen assemblages up to the period of ca. 7000 cal BP, indicating links with the Mediterranean sapropel (S1) sediment layers formation. The late Holocene from ca. 4500 cal BP onwards is characterized by changes in sediment composition which seem to be in agreement with the beginning of the Neoglacial in the Central Mediterranean observed in lake and marine cores from Italy. Pollen data indicate possible human impact (e.g. deforestation, cultivation of Cerealia, Olea) not recorded by mineralogy and geochemistry. Erosion triggered by deforestation during the past millennia is documented in cores from the Zrmanja River catchment by major and minor element geochemistry. Both lake and marine cores provide unique evidence of global Pb pollution during the past two millennia. Various sedimentological, geochemical and biological markers in coastal lakes allow the reconstruction of sea level rise rate and timing, as well as flooding of coastal karst depressions where it was possible to date transitions from lake and marsh into marine environments. The dating of sediments from lakes and marine lagoons so far reviled the existence of tephra ranging from Neapolitan Yellow Tuff(NYT) to Agnano Monte Spino (AMS) and Avellino tephra.

coastal karst ; lake and marine sediment record ; Holocene ; paleoenvironment ; sea-level changes ; human impact

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