Holocene paleoenvironmental changes recorded in the sediments of the karst Krka River estuary (eastern Adriatic coast, Croatia)
Journal
CATENA
Journal Volume
251
Start Page
108811
ISSN
0341-8162
Date Issued
2025-04
Author(s)
Smrkulj, Natalia
Miko, Slobodan
Razum, Ivan
Hasan, Ozren
Brunović, Dea
Ilijanić, Nikolina
Ortler, Marcel
Hus, Petra
Miko, Martina Šparica
Abstract
Karst estuaries are unique and complex systems that develop in microtidal, intense karstification and limited sediment supply conditions. Here, a reconstruction of late Quaternary sea-level fluctuations and environmental changes from Prokljan Lake is presented. Prokljan Lake is a part of the karst Krka River estuary situated in central Dalmatia (Croatia). Subbottom profiles were acquired to examine the basin geomorphology, whereas four sediment cores spanning the Holocene age were used for paleoenvironmental reconstruction. On the basis of sedimentological, geochemical, and paleontological proxies supported by 22 radiocarbon dates, a model of evolutionary progression from the fluvial calcareous tufa barrier system to salt-wedge estuarine conditions is presented. Following the subaerial erosion during the postglacial transgression, a tufa barrier system developed in Prokljan Lake, enabling tufa lake formation with fluvio-lacustrine sediment accumulation until the early Holocene. The sedimentary succession shows dynamic environmental and salinity changes as the Krka River canyon and Prokljan Lake were progressively flooded in the Holocene. Our results revealed a low salinity brackish lacustrine environment at the beginning of the Holocene (ca. > 10.9–8.4 cal kyr BP), with marine intrusion through porous tufas and karst. A further rapid sea-level rise caused an increase in the water depth and flooding of calcareous tufa barriers in the period from 8.4 to 7.5 cal kyr BP, which coincided with the Holocene pluvial period. Further sea-level rise and more arid climate conditions in the period 6.1–3.0 cal kyr BP caused the mixing of marine and freshwater layers, with the formation of a partially mixed or slightly stratified estuary. Late Holocene sediments (3.0–1.9 cal kyr BP) represent sea-level stabilization and the establishment of present-day salt-wedge estuarine conditions. Anthropogenic pressure, manifested as increased catchment-area erosion and organic matter isotopic signature changes, was detected in the last 0.6 cal kyr BP.
Subjects
Croatia
Holocene
Karst estuary
Multiproxy
Paleoenvironmental changes
Sea-level changes
SDGs
Publisher
Elsevier BV
Type
journal article