The Vrgoračko polje is a karst field with a surface area of 37 km 2 and an altitude of between 20 and 28 m above sea level, situated at the southern edge of the Dalmatian Zagora. During the Quaternary the polje was flooded for variable periods of time and a lacustrine environment was established. A multidisciplinary study of drill-cores, outcrops and geoelectric measurements recognised five main sedimentary facies: laminated sediment, redeposited sediment, coarsegrained carbonate debris, littoral clay and lacustrine chalk. Based on the facies analysis, depositional environments developed during the Holocene include aquatic lacustrine littoral and deeper-water environments. The terrestrial environment is represented by a desiccated lake phase. The littoral clay facies (filling depressions and caverns in the karst relief) is laterally equivalent to the deep-water laminated facies (varves?). A stratigraphic break between littoral clay and lacustrine chalk could be time-equivalent to disturbed laminated sediments deposited in deeper-water and to local intercalations of coarse-grained carbonate debris in shallow-water facies sediments. These features could have been the result of a neotectonic event (earthquake), which triggered debris flows of colluvial material from slopes around the lake, and this could also have changed the hydrological regime of the Vrgoračko polje and affected subsequent depositional facies. According to 14 C dating, deposition of the lacustrine chalk started at the beginning of the Mid-Holocene Warm Period (7686±36 aBP) with a sedimentation rate of approximately 0.51 mm a-1 during the Middle, and 0.58 mm a-1 during the Late Holocene to today. Calculated carbonate production was estimated at 1050 gm-2 a-1. A temporary phase of subaerial exposure of the lake is indicated by desiccation cracks and two bioturbated palaeosol horizons. The described depositional environments and sediment facies found in the Vrgoračko polje could be considered to represent a typical Quaternary lacustrine sedimentation pattern for other Dinaric karst poljes. described in the Cerkničko polje, Slovenian Dinaric karst (VAL-VASOR, 1689; PLENIČAR, 1954; SMREKAR, 2000). Similarly, in the karstic Lake Banyoles (NE Spain), MORELLÓN et al. (2014) reported intense groundwater inflow that leads to the fluidization and re-suspension of previously deposited sediments. Seasonal autumn flooding of the Vrgoračko polje may (re)establish a lacustrine environment that lasts through the winter as confirmed by zonal vegetation around the polje (Fig. 1). Likewise, seasonal runoff through estavelles and ponors into the Neretva River (E of the Vrgoračko polje), and the artificial Prigon tunnel draining into the Baćinska Lakes (S of the Vrgoračko polje), leave the Vrgoračko polje dry throughout the summer. The Matica River is the only permanent stream that meanders from its springs in the NW, splits to the south and the east and then sinks (Fig. 1). The altitude difference between the springs, estavelles and ponors is approximately 8 metres. T...
<p>The &#272;ur&#273;evac Sands constitute a wide area of extraordinary small-scale dune relief in the Podravina (northeastern Croatia), along the central part of the southern Drava river valley. They are thought to have been formed by reworking of fluvial material due to strong northern winds. Their significance is evident from the geometry of the dunes (shape, orientation, thickness), and the presence of intra- and post-formational alteration (pedogenesis). In addition, the elevated heavy mineral content puts the sands in the position of potential ore deposit.</p> <p>The objective of this study is to explore this aeolian archive in an attempt to extract relevant palaeo-environmental information and to compare it with similar landscapes across Europe. The lithology (grain-size) and intra-formational alteration (palaeosoils) as well as geochemical signatures are investigated from outcrops in an abandoned sand pit to define phases of sand movement and landscape stability. Radiocarbon dating of charcoal, optically stimulated luminescence (OSL) dating of quartz, and historical archives are used to develop a geochronological framework. The heavy and light mineral fractions of the sands are used to determine their composition, provenance and detailed sedimentological context at the time of deposition. A digital elevation model of the region is used to gain insight into the geometry of the dunes, while geo-electric soundings and mechanical coring are applied to investigate the vertical and lateral variations in sand lithology and thickness, as well as intraformational soils.</p> <p>At first sight, the dune landscape seems to have a chaotic nature, showing an irregular alignment of smaller parabolic, linear and domal shaped dunes. Although, larger structures may also be classified as complex long-walled transgressive dunes or compound en-echelon parabolic dunes. The thickness of the dune sand can clearly be traced on geo-electrical profiles, where the dry dune sand appears to generate a different signal than the underlying water-saturated fluvial material. Furthermore, the results show that phases of sand movement occurred before and after the B&#248;lling-Aller&#248;d (B-A) interstadial, as well as during the early Holocene and up to the 19<sup>th</sup> century. Phases of stability are witnessed by the presence of slightly altered parent material (presence of organic carbon, slightly finer grain size, and decalcified) and are dated to the B-A interstadial, and several episodes in the Holocene. The heavy mineral content is dominated by garnet, while muscovite is strikingly more present in the Holocene sediments. This may be due to either a change in source material (new Holocene Drava river sediment) and/or changing aeolian dynamics. Overall, these new findings obtained from the &#272;ur&#273;evac Sands area correlate rather well with other regions in the Pannonian Basin as well as the North European Plain, especially in terms of the timing of events.</p> <div id="ConnectiveDocSignExtentionInstalled" data-extension-version="1.0.4"></div>
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