Geomorphology of Canyon Outlets in Zrmanja River Estuary and Its Effect on the Holocene Flooding of Semi-enclosed Basins (the Novigrad and Karin Seas, Eastern Adriatic)

Abstract

Detailed multi-beam bathymetry, sub-bottom acoustic, and side-scan sonar observations of submerged canyons with tufa barriers were used to characterize the Zrmanja River karst estuary on the eastern Adriatic coast, Croatia. This unique karst environment consists of two submerged karst basins (Novigrad Sea and Karin Sea) that are connected with river canyons named Novsko Ždrilo and Karinsko Ždrilo. The combined use of high-resolution geophysical data with legacy topography and bathymetry data in a GIS environment allowed for the description and interpretation of this geomorphological setting in relation to the Holocene sea-level rise. The tufa barriers had a predominant influence on the Holocene flooding dynamics of the canyons and karst basins. Here, we describe the possible river pathways from the basins during the lowstand and the formation of a lengthening estuary during the Holocene sea-level rise. Based on the analyzed morphologies and the relative sea-level curve for the Adriatic Sea, the flooding of the Novsko Ždrilo occurred 9200 years before present (BP) and Karinsko Ždrilo was flooded after 8400 years BP. The combination of high-resolution geophysical methods gave an accurate representation of the karst estuarine seafloor and the flooding of semi-isolated basins due to sea-level rise.

The Potential of Tufa as a Tool for Paleoenvironmental Research—A Study of Tufa from the Zrmanja River Canyon, Croatia

“…Additionally, tufa may erode, incorporate some allochthonous terrestrial material and "dead" carbonate, and experience recrystallization [9][10][11]. Reliable dating of tufa enables interpretation of the physico-chemical proxies and can provide many answers on Holocene and Pleistocene palaeoclimate [1,4,6,7,[12][13][14][15][16][17][18][19][20][21][22][23][24][25]. It is essential that the results obtained by different analyses can be put into a correct time frame.…”

Landscapes and Landforms of Terrestrial and Marine Areas: A Way Forward

“…The papers concerning the analysis of terrestrial and marine landforms in coastal and shallow water specifically deal with geomorphological mapping and landscape evolution [22,23], geoheritage and geodiversity [18,19], geohazards [16,20,21], and marine and landscape ecology [28].…”

“…Hasan et al [23] mapped and analyzed the morphological features of the river canyons linking the Karin, Novigrad, and Velebit channels (NE Adriatic Sea). The latter are characterized by tufa barriers that had a role in the Holocene flooding dynamics of the canyons and karst basins.…”

A Holocene Sedimentary Record and the Impact of Sea-Level Rise in the Karst Lake Velo Blato and the Wetlands on Pag Island (Croatia)

“…Holocene sea-level rise data points were determined on specific localities on the Eastern Adriatic Sea: in Lošinj Bay [14,15], in Novigrad and the Karin Sea [44,45], in Veliko Jezero and Stupa Bay on the Island of Mljet [16,27], in Caska Bay on the Island of Pag [20], in western Istria [46], in the Mirna and Neretva valleys [47], and on submerged speleothem records along the eastern Adriatic coast [48,49]. The salt pans and fish tanks were also used as sea-level markers on the eastern Adriatic coast [50][51][52], as well as archaeological and biological markers [53][54][55].…”