Naslov
Lithophyllum rims as markers of relative sea-level change and palaeoearthquakes along the eastern Adriatic coast

Autori
Faivre, Sanja ; Bakran-Petricioli, Tatjana ; Barešić, Jadranka ; Horvatić, Davor

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

Izvornik
Abstract book, 6th Regional Scientific Meeting on Quaternary Geology: Seas, Lakes and Rivers / - Ljubljana, 2021, 1-2

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
Lithophyllum rims, sea-level, palaeoearthquakes, Adriatic

Sažetak
Coralline algae are the most significant framework builders outside the coral-reef belt (Blanc and Molinier, 1955 ; Huvé, 1970). Among them, littoral rims built by the coralline rhodophyte Lithophyllum byssoides are a particularly precise archive of relative sea-level histories (Laborel et al., 1994). Their vertical precision, in the microtidal environment, comes from the restricted environmental conditions of the alga as their living range is constrained around sea-level (Pérès and Picard, 1952, 1964). The temporal component is obtained through 14C dating, consequently vertical and temporal components allow the construction of precise geochronologies. Their potential has been up to now underutilized due to the unresolved question of size of the marine radiocarbon reservoir effect (MRE), prerequisite for accurate calibration of dates obtained from marine-derived carbon samples. In order to approach the 14C reservoir effect different studies of MRE of the alga and shells in the Adriatic and in the other parts of the Mediterranean have been engaged using samples of known age from museum collections (Faivre et al., 2015, 2019a). The corrections of MRE and local R are fundamental particularly for the short, late Holocene sea-level and palaeoenvironmental chronologies. This have been demonstrated in the study of RSL change in Istria in the northern Adriatic (Faivre et al., 2019b) and confirmed in the study of Lopud Island in the southern Adriatic (Faivre et al., 2021). On the Istrian peninsula the high resolution relative sea-level (RSL) reconstruction, based on 47 radiocarbon dates, has been done for the past 1500 yr (Faivre et al., 2019b) what allows to relate sea-level changes to periods of climate changes and to distinguish land-level changes in the studied area. To identify sea-level trends with full consideration of the available uncertainty, the RSL reconstruction was quantitatively analysed using an error in- variables integrated Gaussian process (EIV-IGP) model based on Cahill et al. (2015). A detailed survey of Lopud Island in the Southern Adriatic allowed the distinction of seismotectonically uplifted sector of coast. The established high-resolution algal rim geochronology (based on 23 AMS radiocarbon dates) enable to separate the Late Holocene transgression periods from seismically triggered regression events. Consequently, we distinguished local tectonic uplift (the local non-linear component of RSL change) and provide the first reconstruction of assumed number, timing, and displacements of past seismic events. The most important uplift occurred in well-known AD 1667 Dubrovnik earthquake (Faivre et al., 2021). After correction for local coseismic displacements the sea-level trends with full consideration of the available uncertainty were quantified using an Errors-In- Variables Integrated Gaussian Process model, like in Istria, what allow us to approach the drivers of relative sea-level change and to compare the results. This high-resolution geochronology obtained at Lopud Island allows us to distinguish the effects of coseismic movements on RSL histories what confirmed the precision of L. byssoides bioconstructions not only in the studies of RSL variations but also in the studies of palaeoearthquakes in seismotectonically active areas. This research was supported by Croatian Science Foundation project HRZZ-IP-2019-04-9445 – Relative sea-level change and climate change along the eastern Adriatic coast – SEALeveL.

Izvorni jezik
Engleski

Znanstvena područja
Geografija

POVEZANOST RADA