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TitleThe changing architecture of sea-level lowstand deposits across the Mid-Pleistocene Transition: South Evoikos Gulf, Greece
AuthorAnastasakis, G; Piper, D J W
SourceQuaternary Science Reviews vol. 73, 2013 p. 103-114, https://doi.org/10.1016/j.quascirev.2013.04.018
Year2013
Alt SeriesEarth Sciences Sector, Contribution Series 20130240
PublisherElsevier BV
Documentserial
Lang.English
Mediapaper; on-line; digital
File formatpdf; html
AreaEvoikos Gulf; Aegean Sea; Greece
Lat/Long WENS 24.0000 24.5000 38.0000 37.5000
Subjectssurficial geology/geomorphology; marine geology; continental shelf; coastal studies; sea level changes; sea level fluctuations; Pleistocene; sedimentation; Cenozoic; Quaternary
Illustrationslocation maps; seismic profiles; logs
ProgramGSC Atlantic Division, Director Office
Abstractdirectly dependent on relative sea-level changes. In the past w0.6 Ma, sea-level change has been dominated by asymmetric 100 ka eustatic sea-level cycles, whereas the record of sea-level changes in earlier Pleistocene progradational sequences is less clear. In a steadily subsiding basin in which accommodation balances sediment flux, the depth of a eustatic lowstand determines the paleo-depth of
the deepest clinoform inflection point and the seaward limit of the erosional transgressive surface, whereas the duration of a lowstand controls the amount of progradation that takes place. We report high-resolution seismic profiles of an exceptionally preserved coastal progradational sequence from a coastal embayment in the Aegean Sea that is subsiding at w100 m/Ma. The seismic profiles show clinoforms of smaller amplitude and volume that were deposited before the 100 ka cyclic progradational units. This contrasts with literature reports of complexity in progradational sequences at that time. We assume that published stacked benthic foram O-isotope records are a good proxy for the duration and a reasonable proxy for the amplitude of Pleistocene eustatic sea-level cycles. The MIS 6e5 eustatic sealevel rise is recognised based on sedimentation rates from cores. The underlying major progradational units are correlated with the long-duration, extreme lowstand 100 ka cycles of MIS 6, 12 and 16. Changes in the elevation of lowstand inflection points in clinoforms are used to tentatively extend the record back to MIS 38, by comparison with the benthic foram proxy. The deposits of the higher and longer highstands of MIS 25, 31 and 37 are also recognised. This record provides a testable template for future studies of short early Pleistocene sections on land and raises questions of detail about parts of the published d18O records. It independently supports the recent evidence that the Mid-Pleistocene transition was an abrupt event, with an extreme lowstand in MIS 22.
Summary(Plain Language Summary, not published)
This study reports a remarkable archive of sea-level change over the past 1.2 million years preserved in a coastal bay in Greece. The archive has been imaged by seismic reflection profiling by a scientific colleague at the University of Athens. He sought my advice on interpretation based on my previous publications on similar data. Its importance is that it confirms that the first extreme lowstand of sealevel during the ice ages of the past two million years took place 900, 000 years ago. The finding is applicable to understanding geological records in the offshore marine areas of Canada and potentially to more precise dating of Arctic glacial events that are known to be approximately 1 million years old.
GEOSCAN ID293069