Abstract
The Upper Tortonian and Messinian in the already classic Metochia section on Gavdos Island (Greece) is made up of deep marine, laminated and homogeneous marls with the latter being replaced by evaporitic limestones at the very top of the section. Previous tuning of the section to the La90 time series of northern summer insolation provided ages for sedimentary cycles, polarity reversals, and bioevents. Earlier work on foraminifers and stable isotopes focused on the last 2.45 Myr of the Tortonian and the first 470 kyr of the Messinian. This study extends the stable isotope record and the set of semi-quantitative data on planktonic foraminifers into the youngest 820 kyr of the section which include the precursor and initial stages of the Messinian Salinity Crisis (MSC). New and old foraminiferal oxygen and carbon isotope data have been combined into a ~25 kyr resolution record for the entire pre-evaporitic Messinian and show a major change at 6.74 ± 0.04 Ma which we interpret to reflect an abrupt change in salinity from normal marine to hypersaline and thus marks the prelude to the MSC. Field and thin-section observations on the limestones in the top of the section confirm their evaporitic origin and suggests that salinities has risen to values of >70 psu. We further discuss the biotic response to the two-step salinity increase during the Messinian. Tuning provides an age of 6.00 Ma for the base of the first evaporitic limestone on Gavdos and this age is therefore the age for the onset of the MSC in this part of the Mediterranean. An evaluation of the published ages for the MSC onset in sections Perales (SE Spain), Monticino (N Italy), and Falconara (Sicily) shows that the onset in Falconara, just as on Gavdos, begins at ~6.00 Ma with calcium carbonate precipitation, whereas in Perales and Monticino, onset begins at 5.97 Ma (similar to the currently used age of 5.971 Ma) with gypsum precipitation, i.e. some 30 kyr later than the onset of the MSC on Gavdos and Sicily (Falconara).
| Original language | English |
|---|---|
| Pages (from-to) | 333-360 |
| Number of pages | 28 |
| Journal | Newsletters on Stratigraphy |
| Volume | 55 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 15 Jun 2022 |
Bibliographical note
Funding Information:Acknowledgements. Arnold van Dijk is thanked for measuring the stable isotope samples. Frits Hilgen is thanked for making new lithological data and samples from Falco-nara available and Gioa Bezemer for washing and analyzing the new samples. Previews by Frits Hilgen, Wout Krijgsman and Paco Sierro are greatly appreciated and significantly improved the manuscript. Frank Huiskamp is acknowledged for his help and company on Gavdos in 2003. We further thank Paco Sierro and Wout Krijgsman for making the planktonic foraminiferal respectively paleomagnetic data of the Abad composite section available. Wout Krijgsman further provided lithological data and sample positions for the Monticino section. Arie W. Janssen made the determinations of the Pteropods and small benthic Mollusca from the laminated marls in between the limestones in Metochia. The thoughtful review by an anonymous reviewer was of great help in improving our manuscript. This research was carried out under the program of the Netherlands Earth System Science Centre (NESSC), financially supported by the Dutch Ministry of Education, Culture and Science (OCW).
Publisher Copyright:
© 2021 Gebrüder Borntraeger, Stuttgart, Germany.
Keywords
- Messinian Salinity Crisis
- Mediterranean
- biostratigraphy
- stable isotopes
- tuning
