A 5-million-year record of western Mediterranean Sea level variability


Intellectual Merit

We propose to establish a new and important stable sea level site, Mallorca, Spain, through the study of phreatic overgrowth on speleothems (POS) from its littoral caves. Among the myriad of studies on sea-level using various proxies, those based on POS (a particular type of sea-level-indicator, that stores all information needed for a valid and precise sea-level index point) have important advantages over other sea-level markers. Implications of sea-level reconstructions centered on the POS from the littoral caves of this island are fundamental in understanding the glacial isostatic adjustment (GIA) and dynamic topography in the western Mediterranean basin. The data generated by this research will better constrain estimates of Pliocene and early Pleistocene sea-level available for this time period. Published sea level highstands during past interglacial climate are reportedly significantly above present day sea level. For example, the previous interglacial that occurred between 127,000 and 116,000 years ago when temperatures were ca. 2 degrees C higher than today, has experienced sea level elevations of 3 to 7.5 m above present sea level (mapsl), and Pliocene Epoch sea level highstand elevations are reportedly 9 to 40 mapsl. The precision of these results are still controversial and very few of them rely of radiometric ages; the need for accurate results is of upmost importance if the community is going to realistically model the societal effects of rising sea level by the end of this century. Integrating accurate and precise U/Pb-dated sea level high stand heights over the Pleistocene and Pliocene epochs for each sea-level POS marker, with GIA-enabled models and corrections for dynamic topography will provide the necessary chronologic control for accurately reconstructing sea-level oscillations in western Mediterranean basin.

Broader Impacts

The proposed research has broad impacts as it will generate data that will be of immediate and direct value to geophysicists, oceanographers, and climate scientists who are interested in the fundamental relationships between sea level, ice sheets, and the climate and properties of the solid Earth.

The proposed project will educate and train two graduate students at the University of South Florida and two undergraduate students at the University of Balearic Islands. Thus, the project will directly support the next generation of climate scientists, emphasizing cross training in data acquisition, radiogenic and stable isotope geochemistry, sea-level reconstruction, and GIA modeling. The PIs and graduate students will also participate in K-12 education in Mallorca and will will develop educational materials in English, Spanish, and Catalan to be used in all touristic cave-guided tours as an outreach of this proposal.

Societal impact: The proposed research directly targets the pressing concern posed by currently rising sea levels due to human-induced global warming, thus has a high societal priority.

Created: April 3, 2011

Changed: October 10, 2018

Copyright: Bogdan P. ONAC

Proposal's major goals are:

  1. 1)Produce 30 accurate and precise sea level high stand heights over the Pleistocene and Pliocene epochs

  2. 2)Test whether the RSL in Mallorca is dominated by an eustatic sea level signal with minimal influence by GIA

  3. 3)What is the GIA fingerprint (departure from eustasy) on warm interglacials as indicated by POS sea-level markers

  4. 4)What was the timing, magnitude, and stability of each identified peak sea-level?