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The Prološko Blato is a seasonal karst wetland in the NW part of the Imotsko polje (karst polje) in the Dalmatian hinterland. Ongoing paleolimnological research revealed the existence of Holocene paleolake sediments made of pale brown lacustrine carbonate, rich in gastropods and ostracods, that started to form at ca. 8000 cal yr BP. Multiproxy core analysis, including geochemical, sedimentological, and micropaleontological (ostracods), suggests a relatively shallow, oligotrophic lacustrine environment with continuous carbonate sedimentation until ca. 800 cal BP. Specific to this karstic paleolake is the occurrence of enigmatic botryoidal carbonates initially detected in coarser sieved fractions (>250 um) during the ostracod analysis, and confirmed via SEM analysis. In micropaleontological slides, botryoidal grains occur as plate-like forms, flat on one side and botryoidal (spherical) on the other, implying their growth on a fixed substrate. SEM analysis revealed that botryoidal grains are made of acicular crystals, similar to the needle-like aragonite, exhibiting two distinctive spherulitic forms: a) spherules made of needles radially spreading from the central point outwards, and b) spherules made of needles radially arranged around a circular void. This potentially implies the same formation process, but different stages of development of needle-like crystals. Botryoidal carbonates are numerous in specific samples throughout the paleolake record, which could possibly be used as a proxy for paleoenvironmental interpretation. However, their origin (organic vs. inorganic, diagenetic) and environmental conditions necessary for their formation remain to be investigated.

Submerged marine terraces provide evidence of the past sea-level fluctuations or the effect of the bottom currents. Sea-level changed significantly since the lower Pleistocene, with up to 135 m lower levels than at present. Periods of long-term sea-level stillstands possibly enabled the formation of marine terraces. The formation of the Adriatic Sea bottom currents is related to an interaction between two south-flowing water masses: the North Adriatic Dense Water in the northern Adriatic, and the Levantine Intermediate Water in the Eastern Mediterranean. Bottom-current activity can also form terraced erosional features. The investigated area is located in the central part of the eastern Adriatic, in the SW part of the Žirje island archipelago. The archipelago is characterized by steep island escarpments and submerged islands. The morphology, with almost vertical SW island shores, is typical for the outer rim of the Dalmatian islands and extends to Telašćica and Kornati archipelago. To successfully detect the distribution and characteristics of submerged marine terraces, we used high-resolution acoustic methods – Multibeam Echosounder and CHIRP Sub-bottom Profiler. The results of the detailed survey display abundant evidence of terraced landforms. The resulting landforms can be grouped into five depth-related classes with ranges 53-55 m b.s.l., 70-72 m b.s.l., 80-85 m b.s.l., 100-105 m b.s.l. and 125- 130 m b.s.l. Future investigations will provide an answer to whether studied landforms were created by former sea-level oscillations mainly during the Pleistocene falling stage systems tract, bottom current circulation, or both phenomena had a measurable effect on the formation of the submarine terraces. This work was supported by the Croatian Science Foundation in the project “QMAD” (HRZZ IP-04-2019- 8505).

Lake Velo Blato is a shallow (ca. 3 m deep) coastal lake situated on Pag Island on the Eastern Adriatic Coast (EAC). A 568 cm long sediment core (VB-2) was drilled in the central part of the lake and was analysed by a multiproxy approach. This contribution is focused on the ostracod analysis. In total, 19 species were recognised, belonging to 16 genera. The most abundant species are Cyprideis torosa, Candona angulata, Limnocythere inopinata, Darwinula stevensoni, Cypridopsis vidua, and Cypria ophtalmica. Subordinated species are Paralimnocythere psammophila, Pseudocandona marchica, Herpetocypris sp., Ilyocypris sp., Metacypris cordata, Cypris bispinosa, and Hungarocypris madaraszi. Changes in ostracods assemblages reflect environmental changes for the last 8100 cal yrs BP, specifically paleosalinity and paleohydrology driven by the Holocene sea- level rise. The most evident environmental transition was recorded in the Middle Holocene (at ca. 7100 cal yr BP) and is marked by changes from typical freshwater (Cypridopsis vidua, Paralimnocythere psammophila, Ilyocypris sp., Cypris bispinosa) to brackish (Cyprideis torosa, Candona angulata) associations. This transition is followed by an increase in the Sr/Ca ratio and the occurrence of authigenic Mg-calcite. However, relatively high abundances of L. inopinata and D. stevensoni suggest transition to moderately (oligohaline) brackish conditions, which lasted throughout the Holocene. Salinity increase results from saltwater intrusion through the karstic underground due to the sea-level rise and thus represents a new index point along the EAC for the sea-level curve. However, significant variations in ostracod assemblages during the Late Holocene were observed (e.g. abrupt changes in Cyprideis torosa abundances and valve morphology), which could be related to Holocene climatic variability. Further ostracod analyses (species identification, statistics, and valve geochemistry), coupled with stable isotope geochemistry, will provide more information about Holocene environmental changes in Dalmatia along the Croatian coast.

The distribution and composition of ostracods of the Late Glacial and Holocene in the two cores Prosika 1 (742 cm) and Arta 1 (150 cm) from the karst depression Pirovac Bay can be used to reconstruct palaeoenvironmental conditions and can be interpreted in the context of hydrological conditions and the evolution of the Pirovac Bay during the 14, 100 year-long records. Forty-seven ostracod species from non-marine and marine families Darwinulidae, Candonidae, Ilyocyprididae, Cyprididae, Cytherideidae, Limnocytheridae, Leptocytheridae, Loxoconchidae, Cytheruridae, Trachyleberididae, Cytheromatidae, Pontocyprididae, Hemicytheridae, Xestoleberididae are recognized. Considering results of the multiproxy investigation (palaeontological, lithological, geochemical, and geophysical data), especially ostracod assemblage composition and the presence of benthic foraminifera, two main zones, a freshwater zone (FZ) and a marine shallow-water zone (MZ) with one transitional subzone (TS) are detected. The FZ is characterized by freshwater species typical for the paleoenvironment of an organic-rich, low-energy wetland. In the MZ marine ostracods are represented by shallow marine species. In this zone, marine ostracods are mixed with various allochthonous freshwater taxa. Their mixing can be explained due to the specificity of the karst terrain and the existence of vruljas (freshwater springs under marine water). Between the two zones, the TS includes abundant lake freshwater taxa with rare marine ostracods and benthic foraminifera. The occurrence of rare marine taxa in the TS is connected to the global sea-level rise and first incursion of marine water in Pirovac Bay.

The Krka River Estuary is a microtidal karstic salt-wedge estuary located in the central Dalmatia (Croatia). The upper part of the estuary, i.e. the submerged narrow canyon and the Prokljan Lake, was studied for the first time by multiproxy analyses of 5 sediment cores supplemented with bathymetric and high-resolution seismic data. The aim was to identify the main processes controlling the sedimentary infill and to reconstruct its paleoenvironmental evolution during the Holocene. The study revealed a unique and well preserved submerged paleolandscape with an evolution from lowstand fluvial and lacustrine environment to transgressive and highstand estuarine to marine conditions. Seismic data showed a Pleistocene fluvial incised Krka River valley, with low accumulation rates and sediment bypass towards the Adriatic shelf. At the beginning of the postglacial transgression, a favorable conditions were established for the growth of tufa deposits in the form of barriers with waterfalls. Erosional power of the river was low during this period and fluvial to lacustrine sediments started to accumulate. With further sea level rise, at approx. 10000 y BP, the sea started to inundate the Prokljan Lake. This led to the cessation of tufa growth and the deposition of the estuarine muds with the establishment of the fully estuarine/marine salt-wedge conditions during the highstand (approx. 7500-7000 y BP). Our study revealed a very dynamic paleoenvironmental evolution of the estuary controlled by a rapid sea level rise, local geomorphology and hydrodynamics.

Vast areas of the shallow Adriatic shelf were exposed at the time of the Last Glacial Maximum lowstand. This enabled formation of lakes, river valleys and river floodplains that were submerged during the Holocene transgression. Here we present a study of the karst estuary of the Krka River located in central Dalmatia on the eastern Adriatic coast. The Krka River creates a 23 km long estuary extending north from the Šibenik Channel, over the Prokljan Lake, up to the tufa waterfall Skradinski buk. We used high resolution acoustic methods including sub-bottom profiler (SBP) coupled with multibeam echo sounder (MBES) (MBES bathymetry and MBES backscatter) and side-scan sonar (SSS) to investigate the submerged karst river valley and lake system that existed before the Holocene relative sea level rise. A total of 70 km of SBP profiles and a point cloud of 241 991 638 points in the area of 6.2 km2 were collected during the surveys. Water depth ranges from 5 m b.s.l. in the most northern part of the study area, to 25 m b.s.l. in the southern part of the Prokljan lake. To create a better geomorphological and geological classifications of the seabed, we made a network of 36 ground truthing stations where we sampled sediments with Van Veen grab sampler and obtained underwater images. Sediment samples were analyzed for grain size, bulk density, carbon and nitrogen concentrations, as well as mineralogical XRD analysis and magnetic susceptibility. We combined gathered data with GIS classification tools to create accurate seabed maps of the area. Our results also showed that well-defined submerged river canyon in the Prokljan Lake area was filled with three sedimentary units: fluvial, brackish and marine. Quaternary sediment thickness is up to 15 m. Seabed geomorphology of the investigated area is characterized by many submerged tufa barriers. They are similar to present barriers upstream of the Skradinski buk waterfall. These unique karst geomorphological features, that grow as algae and mosses are encrusted by carbonate, enabled formation of lakes, as well as prevented a marine flooding during the Holocene sea-level rise. The depth of each barrier (4.5 to 12 m b.s.l.), in connection to the onset of marine sedimentation within the estuary, can be used as an indicator of sea level. Barriers are emphasized on the MBES backscatter data as strong reflectors. Grain size of sampled sediments ranges from poorly sorted sand and gravel on underwater barriers to fine silt sediments in the deeper parts of Prokljan Lake. Larger sediment size on barriers is caused by tufa debris while fine silt is sedimented in the deeper parts of the basin. Grain size results vary for different geomorphological provinces, allowing for a more precise (GIS) classification and description of the seabed. This work was supported by the Croatian Science Foundation Project “Sediments between source and sink during a late Quaternary eustatic cycle: the Krka River and the Mid Adriatic Deep System” (QMAD) (HRZZ IP-04-2019-8505).

Freshwater carbonates (tufa deposits) form during interglacial warm periods and can be used as a paleoclimatic and paleoenvironmental indicators. Tufa deposits are typical features of the Dinaric karst of Croatia. In the Prokljan Lake, which is a part of the Krka River estuary located on the eastern Adriatic coast, several submerged tufa barriers were recognized. With the Holocene transgression, the Prokljan Lake drowned and the Krka River estuary was formed. We used detailed multibeam survey (MBES bathymetry and MBES backscatter), side scan sonar and subbottom acoustics to characterize the submerged paleolandscapes of the Prokljan Lake and the upper part of the estuary. The bathymetry and side scan data indicate that the submerged paleolandscape consist of partly burried tufa barriers, small lakes and carbonate mounds. Tufa barriers and carbonate mounds are distinguished on the backscatter data as strong reflectors. Ground truth data was provided in the form of 36 grab samples and seafloor images. Geomorphological and geological classification of the seabed were produced. Sediment samples were analyzed for grain size, magnetic susceptibility, mineral composition (XRD), bulk density and carbon and nitrogen concentrations. Five sediment cores were taken in the lake area and together with the high- resolution seismic profiles, enabled the identification of three sedimentary units: fluvial, brackish and marine. Tufa barriers were probably formed during the transition from the Pleistocene into the Holocene and had a predominant influence on the Holocene flooding of the Krka River canyon. Based on their geomorphology and depth in the Prokljan Lake, the flooding of the Krka River canyon started at approx. 9300 y BP. This multiproxy study allowed a reconstruction of the seabed geomorphology and paleoenvironmental evolution of the Prokljan Lake. The obtained data is also valuable for predicting the estuary response to the future sea level rise.

Prološko Blato is a karst wetland situated in the NW part of the Imotsko polje (Dalmatian hinterland). It is a typical example of Dinaric karst polje, with many hydrogeological and geomorphological features such as lakes, springs, estavelles, making it suitable for multidisciplinary paleolimnological research. We conducted percussion drilling in the polje and geophysical survey (GPR, geoacoustics), supported with aerial photogrammetry, to determine the paleoenvironmental conditions, geomorphological and hydrological changes from the Late Pleistocene through the Holocene. Two sediment cores (6, 5 m and 9, 2 m long) were analyzed by multiproxy approach (sedimentology, mineralogy, geochemistry, micropaleontology) and radiocarbon dating, to determine the time-span of the lake sediments and timing of significant sedimentary changes. Results show that the Last Glacial Period (from ~30 ka cal yr BP to the Early Holocene) is marked by sedimentation of fluvial and possibly fluvioglacial material, that was transported from the mountainous area of western Herzegovina (elevations greater than 2000 m) into the karst polje depression. Numerous dolines (sinkholes) distributed along the NW part of the polje served as depocenters for sedimentary material, while the morphology of these dolines implies their relatively young age of formation and active karstification processes. The Early Holocene (9, 3 - 8 ka cal yr BP) is characterized with siliciclastic sedimentation in an „early lake“ environment of the Prološko Blato, while the Early-Late Holocene (8 – 0, 8 ka yr BP) is marked by the lake deepening and authigenic carbonate sedimentation of lake marl, rich in ostracods, gastropods, and Charophytes. A distinctive lithological change in sedimentation occured at approximately 800 cal yr BP, from lake marl to greyish-brown clay, associated with transition from lacustrine to floodplain environment. Most probably, it is caused by the formation of the Prološko Lake in the eastern part of the Prološko Blato, associated with dissolution processes of limestones, and roof collapsing into an underground cavern, similar to the famous collapse dolines Red Lake and Blue Lake near the city of Imotski. This event corresponds to the well-known period of significant seismic activity in the Dinarides between 1000 and 1200 yr AD. The Imotski region is a seismically very active region, where earthquakes and their primary and secondary effects are historically well documented. The „collapse“ hypothesis is investigated by the paleolimnological research methods since we identified several historical and geomorphological evidence of collapse doline formation, usually after a stronger earthquake (M>5). Final results will contribute to our understanding of the geomorphological and sedimentological processes in the high karst zone of the Dinarides and will give us an insight into the timing and circumstances of the formation of karst lakes in the NW part of the Imotsko Polje.

During a 21-day long cruise onboard the RV Poseidon in the year 2017., a multinational team of scientists collected water and sediment samples in the Adriatic Sea. The cruise POS514 entitled „Micropaleontology, Actuopaleontology, and Environmental Baseline Study of the Holocene to latest Pleistocene in the northern and eastern Adriatic Sea basin“ comprised scientists from German, Italian, Croatian, and Austrian institutions. Scientists measured water column properties with CTD probe, collected biological samples with plankton multi net, and collected sediments with long gravity cores, short multi- cores, Van Veen grabs, Box cores, and Frahm corer on 40 sampling stations (Figure 1a). The gravity core POS514-40-11 GC was collected along the Eastern Adriatic Coast in the northern rim of the Mid Adriatic Pit (Figure 1a) at a water depth of 212.5 m b.s.l. Its total length is 690 cm. The core is of special interest due to the focus of the Croatian Science Foundation project QMAD, with extensive studies in the area of the Krka River estuary and its development towards the MAD during the Pleistocene and Holocene eustatic sea-level fluctuations. The dating of the core was established with five dates using the AMS 14C method, calibrated with the IntCal20 calibration curve in the Clam software (Blaauw, 2010). The oldest date reached 17 900 cal BP at the core depth of 628 cm. The dates were used to create the age-depth model and calculate sedimentation rates (SR) in the MAD (Figure 1b). The peaks of the measured 137Cs activity were not completely conclusive. Other methods used for the core determination include measurements of the particle size (PSA), magnetic susceptibility (MS), carbon and nitrogen (Total C, Total N, C/N ratio, Total Organic Carbon (TOC%), Total Inorganic Carbon (TIC%)), bulk density (BD) (wet and dry), mineralogical (XRD) and derived values as Mass Accumulation Rates (MAR) and Accumulation Rates of C, N, TOC%, and TIC% (Figure 1c). A distinct change in SR, BD, as well as in MAR that starts from 9 440 cal BP to 12 100 cal BP and remains high until the end of the core. Values of the TOC% show the opposite pattern. There is a sudden rise in TIC % and MS at the lower part of the core, at 15 150 cal BP, coincident with a PSA peak of sand particles (Figure 1c). In general, sediments of the whole core are dominantly silty with 20% to 30% of clay-sized particles, with two short sand intervals. The other peak of sand particles occurs at 8 800 cal BP and can also be observed in MAR and TIC%. The C/N ratio is uniform in a range of 7 to 8, with one distinct peak at 13 000 cal BP reaching 9.8. Based on XRD analyses the main difference throughout the core is the amount of two dominant minerals – quartz and calcite. Within the top 2.7 meters (9 700 cal BP) of the core, the amount of the calcite is higher than the quartz, while in the part from the third to the fifth meter (14 700 cal BP) the amount of the quartz is higher. From the fifth meter to the bottom the amount of calcite is again higher than the amount of quartz. This coincides with changes in the other parameters measured within the core (MS, TIC MAR) (Fig 1a). Collected data enabled us to define four distinct zones throughout the core (Figure 1c). The zone POS Z1 extends from the bottom of the core until 15 150 cal BP. It is followed by the POS Z2 zone with a transition to the third zone (POS Z3) at 12 090 cal BP. The youngest and the longest zone POS Z4 extends from the 9 440 cal BP to the surface. Zones Z1 and Z2 deposited in the environment proximal to the coastline, with more pronounced terrestrial and coastal influence on the sedimentation. Zone Z3 represents gradual coastal retreat further from the location due to sea-level rise, with diminishing coastal effect. The youngest zone Z1 was sedimented in the deeper water distal environment that lasts until the present. The obtained results will be extremely helpful in the interpretation of high-resolution acoustic profiling that is planned for the next project period.

A multiproxy investigation has been carried out to study the seabed geomorphology of the Krka River estuary located in the central Dalmatia. A detailed multibeam survey (MBES bathymetry and MBES backscatter), side scan sonar imaging, subbottom acoustics coupled with piston sediment cores and bottom samples were used to characterize 6.2 km2 of submerged paleolandscape of the Krka River valley and the Prokljan Lake. The bathymetry and side scan sonar indicate that the submerged paleolandscape is well perserved and consists of partly buried tufa barrier system with small lakes and carbonate mounds. Geophysical survey consisted of a total of 70 km of seismic profiles, whereas 5 long (4–9 m long) piston sediment cores were collected in the lake area. We identified three sedimentary units, fluvial, brackish and marine, spanning up to 9000 y BP and with thickness up to 15 m. Ground truth data, in the form of grab samples and video transects, were collected at 36 locations in order to create geomorphological and geological classifications of the seabed. Sediment samples were processed for grain size, magnetic susceptibility, bulk density, carbon and nitrogen concetrations and mineralogical analysis. A map of seabed classification was produced using Object- Based Image Analysis (OBIA) by integrating information obtained from multibeam and ground truth data. Tufa barriers are unique karst features and great paleoclimate indicators. They enabled formation of lakes and had a predominant influence on the Holocene flooding of the river canyon. They can be used as an indicator of sea level given their morphology, i.e. depth of each barrier, in connection to the onset of marine sedimentation in the Lake. The results of this study reinforce the idea that submerged tufa barriers in the Prokljan Lake began forming during early Holocene or even during the transition from the Pleistocene into Holocene. Flooding of the river canyons (Guduča River and Krka River) due to sea level rise in the Prokljan Lake started at about 9300 y BP and the formation of estuary at approx. 7500 y BP. Consequently, this multiproxy study allowed a reconstruction of the seabed geomorphology and paleoenvironmental evolution of the upper part of the Krka estuary since the Holocene sea level rise. This work was supported by the Croatian Science Foundation Project “Sediments between source and sink during a late Quaternary eustatic cycle: the Krka River and the Mid Adriatic Deep System” (QMAD) (HRZZ IP04-2019- 8505).

Geological modeling at the Croatian Geological Survey is a developing discipline. In the past few years, a number of geological models were made, mostly for internal use, or as a training result for the ongoing projects, primarily GeoTwinn and Geosekva, while others were built for the purposes of scientific publication. This review will give several examples of selected geological models developed during the past few years period. It will also list different types of geological models and needed typical input data, and give a basic workflow for model building. Geological modeling requires acquisition of different spatial surface and subsurface input data, including primarily digital elevation model – DEM (or similar), different base maps, and other spatial data containing various geological information. Besides the resulting geological model, in the model building process, a whole series of resulting maps and other cartographic outputs are developed.

U ovome radu predstavljena je paleookolišna rekonstrukcija creta u blizini sela Blatuše, s naglaskom na promjene u strukturi i sastavu vegetacije, hidrološkoga režima i povijesti požara na području Banovine/Korduna tijekom posljednja dva tisućljeća. U svrhu paleookolišne interpretacije, napravljena je analiza akumuliranoga peluda, nepeludnih palinomorfa i pougljenjenih čestica. Upotrebom CONISS statističkoga modela mogu se razlučiti tri različite (pod)zone akumulacije: vegetacija „joha-bukva/hrastovi“ dominanira razdobljem od 2. stoljeća do sredine 7. stoljeća, nakon čega slijedi dominacija vegetacije „trave bukva/hrastovi“ do kraja 13. stoljeća, te naposljetku vegetacije „trave-grab/hrastovi“ u razdoblju od 14. do početka 20. stoljeća. Obilje spora maha tresetara (Sphagnum) u razdoblju od 11. do kraja 14. stoljeća vjerojatno je utjecano povećanom količinom oborina i učestalijim padalinama tijekom srednjovjekovne klimatske anomalije. Prijelaz iz ombrotrofije u minerotrofiju same cretne površine, tijekom maloga ledenog doba, uzrokovan je promjenom zasićenosti supstrata vodom, s nešto vlažnijim razdobljem do sredine 17. stoljeća i djelomično sušnijim do početka 20. stoljeća. Iako se pelud žitarica ne pojavljuje do kraja 14. stoljeća i udjeli sekundarnih antropogenih indikatora su niski tijekom cijeloga razdoblja srednjeg vijeka, veliki broj pougljenjenih čestica ukazuje na jaču antropogenu aktivnost no što se to može iščitati iz promjenama u biljnome pokrovu. Ipak, snažan porast udjela peluda nedrvenastih vrsta tijekom Seobe naroda više je rezultat procesa sukcesije na površini samoga creta nego nepobitan dokaz avarsko-slavenskoga utjecaja na sastav i strukturu vegetacije. Izravni antropogeni pritisak, koji se očituje učestalom pojavom peluda korovnih vrsta i žitarica, može se pratiti tek od razdoblja kasnoga srednjeg vijeka nadalje.

During the Last Glacial Maximum (LGM) lowstand, large areas of the Adriatic shelf were exposed. At that time, relative sea level (RSL) was at least 125m lower than present (FAIRBANKS, 1989 ; LAMBECK et al., 2011 ; BENJAMIN et al., 2017). This enabled formation of lakes, river valleys and their floodplains that were subsequently submerged during Holocene transgression (VACCHI et al., 2016 ; ANTONIOLI et al., 2009). Here we present a study of three karst estuaries, Zrmanja, Krka and Cetina, located along the Eastern Adriatic Coast. High resolution acoustic geophysical methods (sub- bottom profiler) coupled with multibeam bathymetry were gathered during the projects QMAD and LOLAdria. Interpreted geophysical data are compared to RSL curve for the Adriatic region (BENJAMIN et al., 2017, LAMBECK et al., 2011). Zrmanja River in northern Dalmatia flows into semi-isolated basin Novigrad Sea, forming 14 km long estuary that ends at tufa barrier/waterfall Jankovića Buk. Geoacoustical survey in the Zrmanja river estuary revealed several tufa barriers located in the narrow canyons connecting Novigrad Sea with open waters and with Karin Sea. During the Holocene lowstand those barriers prevented marine flooding into Novigrad Sea and later to Karin Sea, consequently forming present day estuary. Krka River, located 45 km east from Zrmanja River creates a 23 km long estuary extending to the tufa waterfall Skradinski buk. Geoacoustical survey revealed many submerged tufa barriers similar to present barriers formed upstream the Skradinski buk, as well as a submerged river canyon filled with three sedimentary units: marine, brackish and fluvial. Barriers enabled formation of lakes, as well as prevented a marine flooding during the Holocene sea-level rise. During the Holocene lowstand Krka River formed a river fan some 17 km south of the today’s river mouth, right at the edge of the Mid Adriatic Deep. Present day Cetina river mouth is located at the exit from the canyon in the town of Omiš. Seismic data reveal that during the LGM river did not flow in NW direction as a continuation of today’s flow but created a valley along the coast in SSE direction. In the postglacial period river eroded flysch sequences deposited on the steep hillslopes of Omiška Dinara mountain, and created over 15 m deep and 350 m wide river valley. Due to a Holocene RSL rise, channel was infilled with retrogradational fluvial sediments. Submerged bottom of the valley along Omiška Dinara mountain stands at 81 m b.s.l. Deposition of fluvial sediments started after 13800 BP (LAMBECK et al., 2011). As sediments gradually filled in the channel, Cetina created a 3 km wide floodplain. Thickness of fluvial sediment is 20 m. Fluvial sediments are overlain by 3-5 m thick marine sediment sequence. This work was supported by the Croatian Science Foundation Projects “Sediments between source and sink during a late Quaternary eustatic cycle: the Krka River and the Mid Adriatic Deep System” (HRZZ IP-04- 2019-8505) “Lost Lake Landscapes of the Eastern Adriatic Shelf” (LOLAdria) (HRZZ-IP-2013-11- 9419).

Results of qualitative and quantitative analyses of pollen, non-pollen palynomorphs (NPP) and charcoal particles from the 90 cm long segment of core (depth level 95 to 5 cm) are discussed. Sediment was taken from the Blatuša peatland (Sisačko-moslavačka County), the biggest mire in Croatia, during the year 2015. The lowest section of the analysed core belongs to the Antiquity Epoch with the share of non-arboreal pollen (NAP) of 12%. During the Migration Period the NAP value was dramatically increased (31%) and stayed high (29%) until the beginning of the 20th century. However, the number of anthropogenic pollen indicators and their abundance was very low during Early/High Middle Ages. This paradoxical situation (high share of NAP, low share of secondary and lack of primary anthropogenic pollen indicators) could be explained by the occurrence of NPP, characteristic for peat originating from grasses: Byssothecium circinans and HdV-496. During that period, Molinia caerulea/arundinaceae probably overgrown the mire surface, and supported the high level of NAP, which is usually a useful indicator of both anthropogenic pressure and open landscapes. At the same time, the high shares of Diporotheca webbiae and Brachysporium, characteristic for alder carr, support the hypothesis of a drier phase of the researched area. During the Little Ice Age and later, moisture was increased - conditions transformed the area into a mosaic of wetlands with sedge vegetation, and only sporadically developed peatland vegetation. Finally, the occurrence of Cereals, Vitis and Fagopyrum pollen, together with the high share of Chenopodiaceae, Juglans, Plantago lanceolata and Xanthium spinosum pollen types, offer evidence of economic prosperity and a direct human impact on vegetation during the Late Middle Age and Modern Period.

Magnetic susceptibility (MS) of soils and paleosols indicates the formation of secondary ferrimagnetic minerals (SFM) and pedogenic processes. MS measurements can relatively fast and non-destructively characterize the concentration, mineralogy, and grain size of magnetic minerals present in samples (HATFIELD, 2014 ; PETERS & DEKKERS, 2003). The soil characteristics are influenced by variations in iron mineral forms, and it can give clue to the processes of pedogenesis (DEARING, 1996). Topsoil has been identified as an environment in which ferrimagnetic materials are actively produced. Secondary magnetic minerals (magnetite/maghemite) are mostly ultrafine grained and contain a significant superparamagnetic (SP) component (

Ovim je dokumentom učinjen prvi korak u definiranju geološke, biološke i speleološke podloge izrađene u svrhu buduće prijave područja Imotske krajine za Global Geoparks UNESCO. Priručnik sadrži opći geološki prikaz, regionalne hidrogeološke odnose i hidrogeološke značajke te biološke i speleološke karakteristike geoparka Imotska jezera. Opisano je 10 geoloških točaka/područja: Modro jezero, Crveno jezero, sustav Suvaja-Vrljika (Opačac i Jauk)-Perinuša- Matica, kanjon Badnjevice, Ričice, prijevoj Drežanj-Sridnje brdo, jezero Galipovac, Mamića jezero, Knezovića jezero, Prološko blato, spilja Zovnjača i izvor Krčevac.

Geološka interpretacija snimaka geološkog dubinomjera i granulometrijska analiza uzoraka morskih sedimentata između kopna i otoka Drvenika

A unique characteristic of post-LGM marine transgression reconstructions is the use of submerged archaeological RSL indicators, such as shell middens, coastal buildings, or traces of human occupation. In the rare cases when underwater archaeological research takes place on those sites, it involves diving and excavation, both of which represent a stressful risk for the archaeologists and the investors. The high likelihood of a negative archaeological result, regardless of the promising preliminary surveys, most often means that archaeological research is considered unreliable or unnecessary. This can change by applying interdisciplinary research methods, where environmental data can also answer archaeological research questions. A geoarchaeological submerged case study in Zambratija Bay, Croatia, demonstrates alternative ways to use seabed core environmental data, by using multiproxy analysis of a nearby sediment core (sedimentological, mineralogical, geochemical and palinological analyses). Preliminary archaeological, geophysical investigations and analysis of dated cores revealed that the site, today submerged three metres under the Adriatic Sea, is a 6, 000- year-old freshwater pile-dwelling built on the outer edges of a karstic sinkhole. Seven cores taken on site revealed that the submerged sinkhole contains marine, brackish, organic and lacustrine sedimentary sequences. Holocene marine transgression is evident by marine carbonate sediments containing marine shells, covering terrestrial grey and brown clay sediments. These clayey sediments show succession from highly magnetic sediments containing pyrhotite minerals, formed under marine influence through karstic underground. One-meter thick organic sediments are composed of peaty sediments with high TOC (15-30 %) and N (1.1-2.8 %) and compact fine-grained peat with high P, Fe and Mo, as well as significant amounts of vivianite. These organic sediments are characterised by lower values of δ13C and δ15N implying freshwater environment. Occurrences of vivianite are still visible in underlying brown clay freshwater pond sediments, containing much more siliciclastic material compared to above organic sediments. Vivianite is a mineral that occurs on various Quaternary, postglacial and modern aquatic systems worldwide, which includes marine, freshwater and terrestrial waterlogged soils. It is known to appear on archaeological sites in teeth and bones on waterlogged bodies, and anthropologically influenced muddy wastewater layers settings with higher P levels, which implies that its occurrence might indirectly mirror a human impact on aquatic environments.

The Prološko Blato area is seasonally flooded, north-western part of the Imotsko polje (karst polje) situated in the central part of Dinaric karst. It is made of Quaternary lacustrine sedimentary sequence surrounded by Cretaceous carbonates. Fluctuating water level turns the environment from wetland to grassland. This transition represents a period of erosion and formation of distinctive erosional channels, which are then suitable for mapping and sampling of sediments. The eastern part of the Prološko Blato called Prološko Lake, is according to BONACCI & ROJE-BONACCI (2000) an estavelle. This is a typical Dinaric karst landscape that contains numerous geomorphological features: springs, streams, and dolines. Later ones seem to be the most significant in the context of climate change and environmental protection of this remarkable karst phenomenon. The preliminary field research included: core drilling, sediments sampling, side-scan sonar measuring, and digital photogrammetry by ShapeMetriX3D (3G SOFTWARE & MEASUREMENT GMBH, 2007). Laboratory work included: high- resolution core analysis, radiocarbon dating, geochemical, mineralogical and grain-size analysis, as well as micropaleontological analysis of ostracods. Additionally, geomorphological analysis of the Prološko blato, its catchment area, and surrounding dolines was conducted using various spatial input data. The lacustrine sequence is about 7 meters (or more) thick and divided into lacustrine deposits with alluvial influence at the bottom and carbonate deposits with clays at the top. Carbonate deposits belong to the Holocene and can be characterized as lacustrine chalk that started to form approximately 9 600 cal yr. BP. It is rich in calcium and well- preserved fossils of ostracods, gastropods, and charophytes. The lower part of the Holocene section is a dark siliciclastic mud determined as black and brown clays with great lateral continuity. Their formation is related to strong erosional input, evident in the significant increase of magnetic susceptibility, higher content of siliciclastic elements and lack of ostracods. They were forming between 11 250 and 9 600 cal yr. BP. Beneath the clays come lacustrine deposits with clear alluvial influence belonging to the period of intensive erosion and deposition of poorly sorted sands and silts, with numerous gravel lenses defined as alluvial paleochannels. It is presumed that alluvial deposits belong to the Late Pleistocene period. These are followed by the thick bluish-gray clay, again rich in ostracods. The Prološko Blato can be divided into the paleolake in the western, and modern lake in the eastern part. Its central basin was probably in the western part, evident in the absence of alluvial paleochannels and increasing thickness of lacustrine sediments. The Prološko Lake is categorized as a collapse type of doline (FORD & WILLIAMS, 2007) filled with water, i.e. karst lake, having a steep north-eastern sidewall with characteristic red to orange color. Its formation may be related to the strong tectonic activity of the area (DRAGIČEVIĆ et al., 1999), combined with the dissolution processes. Existence of a paleolake with the constant water level was presumably disrupted by the collapse of Prološko doline. This event may have been crucial in the development of the present hydrogeological system and can be used for future predictions, giving the fact that dolines are still forming both in lowland and highland part of the Imotsko polje, particularly subsidence type of dolines (FORD & WILLIAMS, 2007 ; MARŠIĆ, 2011). These hypotheses will be investigated with more detailed digital photogrammetry and core drilling. For further understanding of the underground karst features and paleolake extent, geophysical methods (electrical resistivity tomography, georadar, and multibeam sonar) will be of great importance.