the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 12 Feb 2025
Insights into the Middle-Late Miocene palaeoceanographic development of Cyprus (E. Mediterranean) from a new δ18O and δ13C stable isotope composite record
Abstract. The Middle to Late Miocene was a time of significant global climate change. In the eastern Mediterranean region, these climatic changes coincided with important tectonic events, which resulted in changes in the organisation of oceanic gateways, altering oceanic circulation patterns. The Miocene Climatic Optimum is regarded as the most recent CO2-driven warming event in Earth’s climate history and has been proposed as an analogue for future climate change. We present a c. 12 Ma record of oxygen and carbon stable isotopes from the Island of Cyprus to help constrain the nature and extent of Miocene palaeoceanographic changes in the eastern Mediterranean region. Cyprus includes Neogene deep-sea pelagic sedimentary rocks which are suitable for stable isotope studies. Our composite geochemical record integrates data from the Lower-Upper Miocene succession at Kottaphi Hill along the northern margin of the Troodos ophiolite, and the Upper Miocene succession at Lapatza Hill to the south of the Kyrenia Range. Calcareous nannofossil biostratigraphy reveals that the composite record spans the Miocene Climatic Optimum's onset to the beginning of the Messinian Salinity Crisis. The new stable isotopic record reveals a complex interplay between global climate change and regional-to-local tectonic changes. In the earlier part of the record, global climate change dominated; however, by the end of the Late Miocene, tectonic events culminated in isolation of the Mediterranean basins, resulting in a deviation from the global open-ocean trends. Strontium isotope analysis was used primarily to help constrain the age of the Miocene successions sampled but also implies changes in the connectivity of eastern Mediterranean basins during the Late Miocene. This research provides a useful reference for oceanographic changes during the Miocene of the Eastern Mediterranean compared to the global oceans.
- Preprint
(2507 KB) - Metadata XML
-
Supplement
(805 KB) - BibTeX
- EndNote
Status: final response (author comments only)
-
RC1: 'Comment on egusphere-2025-442', Isabella Raffi, 28 Mar 2025
The overall quality of this manuscript is very good. It is a well thought out study on stratigraphic successions of Cyprus Island that provides insight on the Middle-Late Miocene paleoceanographic history of the Eastern Mediterranean. The study presents a composite geochemical record of oxygen and carbon stable isotopes, precisely dated through nannofossil biostratigraphy and strontium isotope dating technique.
The scientific approach and applied methods are correct and provide a valid documentation that includes sections properly selected for sampling, based upon accurate stratigraphic analyses. This accuracy successfully helped in the reconstruction of tectonic development in the eastern Mediterranean marine basins during the Miocene. Through detailed sedimentary logs of the two chosen sections, nannofossil biochronology and strontium isotope dating the authors obtained a reliable age model with which the temporal composite 18O and 13C record is constructed, with the final aim to provide a reliable climatic and environmental reconstruction for the study area. It seems that the objective has been achieved: results and conclusions are clearly presented and complemented by a sufficient number of figures (of good quality) and tables. The abstract properly summarizes the results and the scientific substance of this study.
A marginal observation regards the calcareous nannofossil biostratigraphy applied in this study: besides the used reference scheme (by Backman et al., 2012), that is appropriate for providing a reliable age model, the Authors could address a more recent biostratigraphic review on nannofossil biostratigraphy in the Mediterranean [the reference is: A. Di Stefano, N. Baldassini, I. Raffi, E. Fornaciari, A. Incarbona, A. Negri, S. Bonomo, G. Villa, E. Di Stefano, D. Rio (2024). Neogene-Quaternary Mediterranean Calcareous Nannofossil Biozonation and Biochronology: a Review. Stratigraphy, 20(4): 259-302. https://doi.org/10.29041/strat.20.4.02]. Anyway, it is not a mandatory suggestion because it will not change the biochronologic results presented.
I do not have to address any other specific question on the manuscript contents, the paper provides new data in the studied area and represents an interesting contribution to the paleoenvironmental evolution of the Eastern Mediterranean.
Citation: https://doi.org/10.5194/egusphere-2025-442-RC1 -
AC1: 'Reply on RC1', Torin Cannings, 29 Apr 2025
We thank Professor Isabella Raffi, for taking the time to review the manuscript and provide valuable comments. We have noted the more recent biostratigraphic framework presented in the referenced review paper. In the revised article, we will add a brief statement confirming that our results are also consistent with the updated biostratigraphy, citing the new article. We initially carried out the biostratigraphic dating prior to the publication of this article, but we agree that it is best to cite the most up-to-date schemes.
Overall, the suggested changes and additions by both reviewers will improve the manuscript’s readability and coherence, and we are grateful to have these brought to our attention.
Citation: https://doi.org/10.5194/egusphere-2025-442-AC1
-
AC1: 'Reply on RC1', Torin Cannings, 29 Apr 2025
-
RC2: 'Comment on egusphere-2025-442', Helmut Weissert, 10 Apr 2025
Torin Cannings and colleagues present a new stable C- and O-isotope data set from the island of Cyprus covering the Miocene. This data set adds new and detailed information on globally well documented changes in carbon cycling and related fluctuations in temperature during the Miocene. Their data provide additional evidence on stepwise Late Miocene closure of the Mediterranean. Closure of gateways had a major impact on regional isotope patterns stored in studied pelagic sediments. The authors present a bio- and chemostratigraphically well-defined age model for the pelagic sections chosen for this investigation. A good age model is essential for correlation of this new dataset with existing records from other regions of the Mediterranean and elsewhere.
I recommend publication of this manuscript in Climate of the Past after some (minor) revisions.
Comments and suggestions:
Structure of the manuscript.
-The authors include a rather detailed discussion of published chemostratigraphies and interpretation of these data in their introductory chapter. Some of this discussion might be more appropriately integrated in the discussion paragraph following the presentation of the data. Currently, the authors repeat parts of the introduction's summary in their discussion paragraph (e.g. the temperature trend discussion of the identification of the carbon isotope events). I recommend that the authors shift at least part of the long climate and ocean introduction (around lines 90-125, possibly also some of sentences in lines 55-60) to the discussion. This minimizes redundancies in the discussion.
-Additional references in the introduction: Cedric John et al., 2003, GSA, on Miocene climate in the Mediterranean.
-Line 117: see also impact of closure of gateway to the east on Mediterranean isotope records in Jacobs et al., 1996.
Data
310 are condensed intervals comparable to phosphorites in the central and western Mediterranean? (see Jacobs et al., hardgrounds 16.9 and 16. 1 Ma). Any evidence for changing deep current intensities?
415 onwards: stable isotope values expressed in the d-notation are not “heavier” or “lighter” but more positive/negative.
484 correct the title
From 499 onwards: Please add isotope events (Mi 3, 3a, 4, MMCT, LMCIS etc.) to your summary figure 10. This will facilitate readers comprehension of your argumentation.
519 delete “n”
525-530 > some duplication, see your introduction, lines 65-75
Citation: https://doi.org/10.5194/egusphere-2025-442-RC2 -
AC2: 'Reply on RC2', Torin Cannings, 29 Apr 2025
We would like to thank Professor Helmut Weissert for reviewing the article and providing valuable guidance for its improvement. We agree that the introduction and discussion can be streamlined to improve flow and reduce duplication; these changes will be incorporated into the revised version of the manuscript. Some of the more specific information given in the introduction will be moved to the discussion. Doing this will keep the introduction as an overview and reduce duplication.
The additional references by John et al. (2003) and Jacobs et al. (1996) will also be added. The ‘firmground’ interval at Kottaphi Hill may be comparable to those observed in Malta, and we will mention this possibility. While a detailed analysis of these layers was beyond the scope of this study, a future effort to compare and potentially correlate such intervals across the Mediterranean would be a valuable direction for further research.
We will revise the phrasing around ‘lighter’ and ‘heavier’ stable isotope values for improved precision. Adding isotope stages and events to the summary will indeed enhance the figure's usefulness for readers; these additions will be made together with the existing annotations.
The in-text editorial corrections noted will also be implemented.Overall, the suggested changes and additions by both reviewers will improve the manuscript’s readability and coherence, and we are grateful to have these brought to our attention.
Citation: https://doi.org/10.5194/egusphere-2025-442-AC2
-
AC2: 'Reply on RC2', Torin Cannings, 29 Apr 2025
Viewed
| HTML | XML | Total | Supplement | BibTeX | EndNote | |
|---|---|---|---|---|---|---|
| 212 | 83 | 16 | 311 | 30 | 14 | 17 |
- HTML: 212
- PDF: 83
- XML: 16
- Total: 311
- Supplement: 30
- BibTeX: 14
- EndNote: 17
Viewed (geographical distribution)
| Country | # | Views | % |
|---|
| Total: | 0 |
| HTML: | 0 |
| PDF: | 0 |
| XML: | 0 |
- 1