Geomorphological features of pleistocene landscape of the Koločep's canal watershed : master's thesis

Na temelju geomorfološke analize i interpretiranih seizmičkih profila te globalnih krivulja izdizanja morskih razina napravljena je preliminarna rekonstrukcija prostora bazena Koločepskog kanala. Unutar bazena nalazi se 9 akustičnih jedinica koje su interpretirane kao izmjene marinskih i jezerskih uvjeta sedimentacije. Tijekom posljednjeg glacijala u središnjem dijelu bazena došlo je do intenzivne erozije starijih naslaga, a erodirane sedimente su transportirali vodotoci koji su imali svoje izvore na mjestu današnjih vrulja i priobalnih izvora. Tvorili su danas potopljenu „Mljetsku rijeku“. Tijekom aridnog LGM-a, eolski pijesak je zatrpao korito „Mljetske rijeke“ u kanalu Veliki Vratnik (danas na dubini od -50 m) što je dovelo do stvaranja jezera u depresiji nastaloj erozijom starijih naslaga. Uočeno je niz rasjeda unutar bazena, gdje akustični profili naslaga ukazuju da su neaktivni nakon taloženja najmlađih akustičnih jedinica (poslije LGM – a). Istočni dio bazena nalazi se još uvijek u fazi izdizanja duž rasjeda koji je bio aktivan za vrijeme starijeg pleistocena i u holocenu, što se manifestiralo kao izdizanje morskog dna duž rasjedne plohe. Blizina epicentra Stonskog potresa iz 5.9.1996.godine ukazuje na mogućnost veze sa navedenim rasjedom.The preliminary reconstruction of the Koločep canal basin area is based on geomorphological analysis and interpreted acoustic profiles, as well as on global curves of sea level elevation. Inside the basin, there are 9 acoustic units which have been interpreted as changes between marine and lake conditions of sedimentation. During the last glacial period, an intensive erosion of old sediments emerged in the central part of the basin and after that sediments were transported by watercourses which had their own costal wells and „vruljas“ (watersprings bellow sea) at the locations that are equal to their recent locations. They formed the Mljet river that is today submerged. During the LGM, the waterway of the Mljet river in Veliki Vratnik canal (-50 m deep at this location) got covered with the eolic sand during the arid LGM, resulting in the emergence of a new lake in the depression created by the erosion of old sediments. Series of faults inside the basin were identified by observation of acoustic profiles of sediments that imply their inactivity after the sedimentation of the youngest acoustic units (after the LGM). The eastern part of the basin is still in the process of elevation along the fault which was active during older Pleistocene and Holocene, which resulted in the elevation of the seabed along the fault plane. The vicinity of the Stone earthquake's epicenter points to a possible connection with the events in the previously mentioned fault area