Sea level reconstruction based on vertical distribution of grain-size parametri and carbonate content in beach ridge plains
Authors: Stan Ionel Bogdan 
Published: March 2022

&lt;p&gt;Sea level reconstruction based on vertical distribution of grain-size parameters and carbonate content&amp;#160;&lt;br&gt;in beach ridge plains&lt;br&gt;Ionel-Bogdan STAN1*&lt;br&gt;, Alfred VESPREMEANU-STROE1,2, Luminita PREOTEASA1,2, Laurentiu TUTUIANU1&lt;br&gt;1 GEODAR Research Center for Geomorphology, Geoarchaeology and Paleo-Environments, Bucharest University, 1 N. B&amp;#259;lcescu,&amp;#160;&lt;br&gt;01004 Bucharest, Romania;&amp;#160;&lt;br&gt;2 Sf&amp;#226;ntu Gheorghe Marine &amp; Fluvial Research Station, Faculty of Geography, Bucharest University, Sf. Gheorghe, Tulcea,&amp;#160;&lt;br&gt;Romania;&lt;br&gt;*Correspondence to: Stan Ionel Bogdan. E-mail: ionel.bogdan.stan@gmail.com&lt;br&gt;KEY WORDS: SLIP, SEA-LEVEL in Late Holocene, Western Black Sea&lt;br&gt;Accurate sea-level reconstruction is important in modelling and anticipating the effects of currently&lt;br&gt;accelerated eustatic changes and the associated landscape changes.&lt;br&gt;The methodologies that determine the paleo-sea level currently involve various level indicators - Sea&amp;#160;&lt;br&gt;Level Index Points (SLIP) -, such as: (a) basal peat (formed in lagoons and swamps whose substrate is&amp;#160;&lt;br&gt;very close to contemporaneous mean sea level), (b) biological indicators: those species that support&amp;#160;&lt;br&gt;very shallow depths or that live at known depths, (c) speleothems (which cannot directly quantify sea-&lt;br&gt;level, but may indicate a maximum level below which the sea surface was during their formation), (d)&amp;#160;&lt;br&gt;archaeological material of past sea level significance (e.g., harbour structures), (e) marine terraces. Yet,&amp;#160;&lt;br&gt;the uncertainty range of these SLIPs is large and new and more accurate indicatora are necessary.&amp;#160;&lt;br&gt;Our previous studies on the morphology and sedimentology of beach ridge plains from Danube Delta&amp;#160;&lt;br&gt;(Preoteasa and Vespremeanu-Stroe, 2010; Vespremeanu-Stroe et al., 2016) suggest the imprint of the&lt;br&gt;mean sea level on the vertical distribution of textural parameters of sediments in the (former) foreshore&amp;#160;&lt;br&gt;system, especially on the beach face and berms. In the present study, we examined the vertical&amp;#160;&lt;br&gt;distribution of the sedimentary parameters and inorganic carbonate content along cross-shore profiles&amp;#160;&lt;br&gt;on several beach ridge plains from the Danube delta to capture those changes attributed to mean sea-&lt;br&gt;level changes on a larger time scale. OSL dating of the berm sediments on successive beach ridges was&amp;#160;&lt;br&gt;undertaken to constrain the chronological framework of the BRP formation and sea-level variation.&lt;br&gt;Our analysis shows the content of inorganic carbonates usually increases within ca. 15-30 cm envelope&amp;#160;&lt;br&gt;near the mean sea level and that the sediment sorting becomes poorer in the mid and lower beach face&amp;#160;&lt;br&gt;zone comparative to the upper beach face and berm sediments. These results supports a new method to&amp;#160;&lt;br&gt;track sea-level in beach ridge plains at a comparatively better resolution. A preliminary sea-level curve&amp;#160;&lt;br&gt;for the last 3500 years was obtained based on new data from Danube delta strandplains which shows&lt;br&gt;clear fluctuations in sea level during different climatic periods.&lt;/p&gt;