Naslov
Core MIR1: A 34-M long Holocene archive at the mouth of Mirna River (Northern Istria, Croatia)

Autori
Fontana, Alessandro ; Felja, Igor ; Juračić, Mladen ; Furlani, Stefano ; Rossato, Sandro ; Novellino, Massimo D. ; Pini, Roberta ; Ravazzi, Cesare ; Correggiari, Anna Maria ; Asioli, Alessandra ; Taviani, Marco ; Vigliotti, Luigi

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

Izvornik
6th Regional Scientific Meeting on Quaternary Geology: Seas, Lakes and Rivers Ljubljana, 27–29 September 2021 Book of abstracts E-book © 2021, Geološki zavod Sovenije, Ljubljana / Petra Jamšek Rupnik, Ana Novak - Ljubljana, 2021, 20-21

Skup
6th Regional Scienfic Meeting on Quaternary Geology: Seas, Lakes and Rivers

Mjesto i datum
Ljubljana, Slovenija, 27.09.2021. - 29.09.2021

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Holocene, Mirna River, Adriatic, sediment core

Sažetak
Along the eastern side of the Adriatic the index points of past relative sea level are few and almost completely related to the upper Holocene. The possibility to find significant information about the relative sea level during the Early and middle Holocene is related to the rare settings where sedimentary sequences recorded that interval, as in the few deltaic plains and enclosed basins (e.g. Brunović et al., 2019). This situation exists at the mouth of the Mirna River, near the city of Novigrad (Croatia), that has the largest fluvial catchment of Istria and experienced a deltaic progradation of about 12 km along the final tract of its karst valley (Felja et al., 2015). This research analysed the Holocene deposits recorded in core MIR1, that was drilled near the mouth of the Mirna River down to a depth of 120 m and documented that the thickness of Holocene sediments is about 34 m. The core was investigated for its sedimentology and stratigraphy, supported by several analytical methods which considered in detail the following properties: grain size, radiocarbon, C/N, molluscs, foraminifers, pollen, magnetic susceptibility. The Holocene sequence documented in core MIR1 is an expanded record that allows a detailed investigation of the paleoenvironmental evolution. In particular, the quantitative analyses of pollen and foraminifers, coupled with nine radiocarbon dates, support the detection of the subtle variations of salinity and vegetation cover. The marine transgression reached the area about 10.4 ka cal BP and was afterwards characterized by a lagoon environment with a relative temporary stillstand of the sea between 9.7-9.3 ka cal BP, when the level was around -31 m Mean Sea Level (MSL). This setting was after modified by the rapid drowning of the valley and transformed into an estuary. The maximum flooding occurred in the valley around 7 ka cal BP, when the coastal environment probably almost reached the area of Ponte Porton, 12 km inland, and the deltaic progradation started. The coast reached its present position only few centuries ago, when the reclamation activities started and were completed during the first part of the 20th century. A vertical aggradation of over 10 m occurred in MIR1 between 5.5 and 4.0 ka cal BP, when the delta front was near the borehole site, creating a very expanded record of the alluvial history of the river. During the Late Roman period salt marshes characterized the present mouth area, where their sedimentary facies are found at a depth of -2.5 m MSL. 21 Core MIR1 also documents an expanded and continuous sequence of the Last Interglacial, thus the Holocene interval represents an important analogue for inferring changes and similarities between the present and the Last interglacial conditions along the eastern side of the Adriatic.

Izvorni jezik
Engleski

Znanstvena područja
Geologija, Interdisciplinarne prirodne znanosti

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