Naslov
Reconstruction of the late Quaternary deposition system of the Koločep Channel (Croatia): paleohydrogeology and paleoseismicity

Autori
Šolaja, Dragana ; Miko, Slobodan ; Papatheodorou, George ; Hasan, Ozren ; Marković, Tamara ; Christodoulou, Dimitris ; Brunović, Dea ; Ilijanić, Nikolina ; Gusić, Ivan

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
5 th regional scientific meeting on Quaternary geology dedicated to geohazards and final conference of the LoLADRIA project "Submerged Pleistocene landscapes of the Adriatic Sea" / Marjanac, Lj. - Zagreb : Hrvatska akademija znanosti i umjetnosti (HAZU), 2017, 66-67

Skup
5 th regional scientific meeting on Quaternary geology dedicated to geohazards and final conference of the LoLADRIA project "Submerged Pleistocene landscapes of the Adriatic Sea"

Mjesto i datum
Starigrad, Hrvatska, 09.11.2017. - 10.11.2017

Vrsta sudjelovanja
Poster

Vrsta recenzije
Podatak o recenziji nije dostupan

Ključne riječi
Late Pleistocene, Holocene, sediment cores, geophysics, hydrogeology

Sažetak
The Koločep channel is located between the coast and Elafiti islands in the Dubrovačko- neretvanska County (southern Croatia). The average width of the channel is 1.5 km. The distance between the mainland and the island of Koločep is about 1 km at the narrowest part of the channel. The reconstruction of the Koločep channel basin area is based on geomorphological analysis and interpreted acoustic profiles, as well as on global curves of sea level elevation. The consequence of sea-level rise is the steep, rocky, and primarily transgressional coastline, where coast-parallel anticlines (analogous to inland mountains) have formed island chains, while coast-parallel synclines (analogous to inland depressions) have become bays and channels (Pikelj & Juračić, 2013). On highresolution acoustic profiles 9 acoustic units were recognized. This units indicate exchange of marine and lacustrine sedimentary environments. During the last glacial period, intensive erosion of old sediments occurred in the central part of the basin. Dating of the samples from sediment core using AMS 14C method provides ages of 9669 cal BP and 12170 cal BP, at core depths of 1.55 m and 2.51-2.53 m, respectively. Sediments were afterwards redeposited by watercourses which created coastal wells and vruljas in similar locations to those at the present day. Over the area vruljas and springs are defined that can be related to the underground flows of the rivers Trebišnjica (BiH) and Neretva (CRO). Based on the ponors from the Popovo Polje (BiH) on the western side of the Trebišnjica watershed, we can define groundwater flows with the coastal springs and vruljas Slano and Doli (Fig. 1) (Vranješ et al., 2000). Under natural conditions, dewatering of the Popovo polje was only possible through the underground karst channels (Milanović, 2014). These coastal wells and vruljas formed the Mljet River that is now submerged. During the LGM (Last Glacial Maximum), the waterway of the Mljet River in the Veliki Vratnik channel (-50 m deep at this location) was covered with the eolian sand during the arid LGM, resulting in the emergence of a new lake in the depression created by the erosion of old sediments. A series of faults inside the basin were identified by observation of the acoustic profile of sediments that imply their inactivity after sedimentation of the youngest acoustic units (after LGM). The eastern part of the basin is still in the process of elevation along the fault which was active during the Pleistocene and Holocene, which resulted in the elevation of the seabed along the fault plane. Koločep channel is located in the area with the most frequent earthquake concentrations in Croatia (Šundov, 2012). The last significant earthquake occurred near Ston in 1996, with a magnitude 6.0. The vicinity of the earthquake’s epicentre points to a possible connection with the events in the previously mentioned fault area.

Izvorni jezik
Engleski

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