ALBERT

Description: We report the results of tephrochronological studies on marine cores from the eastern and western part of the Sea of Marmara extending back to early MIS-4. Glass shard compositions using electron probe microanalyses (EPMA) and stratigraphic analysis assigned three distinct tephra layers to the eruption of Avellino (Somma-Vesuvius/Italy, 3.9 ka), Cape Riva (Thera/Santorini, 22 ka) and the Campanian Ignimbrite (Phlegrean Fields/Italy, 39.3 ka), respectively. Tephra layers are important chronostratigraphic markers for the refining of age-depth models of cores and thus for the reconstruction of the palaeoceanographic evolution of the Sea of Marmara. Accordingly, a continuous sedimentary record for the last ca. 67 ka in core MD01-2430, located at -580 m on the Western High, shows only one lacustrine-marine transition at 12.55 ± 0.35 cal ka BP, which indicates that the Sea of Marmara was under lacustrine conditions disconnected from the Mediterranean Sea from early MIS-4 to early MIS-1. High lake levels and oxic bottom water conditions prevailed especially during the MIS-3 stadials. This implies that the sill depth of the Çanakkale Strait (Dardanelles) was probably higher during MIS-3 time than the present sill depth of -65 m. Alternatively, strong fresh water discharges from the Black Sea during the interstadials might have kept the Sea of Marmara stratified with a relatively thick layer of fresh waters above a weak Mediterranean inflow filling only deeper parts of the basins. Based on the radiocarbon and tephra-integrated age model the marine transgression at 12.55 ± 0.35 cal ka BP was followed by the deposition of the main lower Holocene sapropel between ca. 12.3 and 5.7 cal ka BP, and in the shallow shelf areas (〈~100 m depth) such as the Gemlik Gulf, by the formation of the upper Holocene sapropel between ca. 5.4 and 2.7 cal ka BP.

Description: Using offshore geodetic observations, we show that a segment of the North Anatolian Fault in the central Sea of Marmara is locked and therefore accumulating strain. The strain accumulation along this fault segment was previously extrapolated from onshore observations or inferred from the absence of seismicity, but both methods could not distinguish between fully locked or fully creeping fault behavior. A network of acoustic transponders measured crustal deformation with mm-precision on the seafloor for 2.5 years and did not detect any significant fault displacement. Absence of deformation together with sparse seismicity monitored by ocean bottom seismometers indicates complete fault locking to at least 3 km depth and presumably into the crystalline basement. The slip-deficit of at least 4 m since the last known rupture in 1766 is equivalent to an earthquake of magnitude 7.1 to 7.4 in the Sea of Marmara offshore metropolitan Istanbul.

Description: Integrated Ocean Drilling Program (IODP) Expedition 333 returned to two sites drilled during IODP Expedition 322 on the ocean side of the Nankai Trough to pursue the characterization of the inputs to the Nankai subduction and seismogenic zone, as part of the Nankai Trough Seismogenic Experiment (NanTroSEIZE) multi-expedition project. Site C0011 is located at the seaward edge of the trench and Site C0012 on a basement high, Kashinozaki Knoll (Fig. 1). The main objectives of drilling again at these sites were to fill coring gaps in the upper part (〈350 m) of the sedimentary sequence, to measure heat flow, and to core the oceanic basement to a greater depth on the Knoll. New results include the observation of a diagenetic boundary within the Shikoku Basin sediments that may be compared to one documented further west by ODP Legs 131, 190 and 196 but occurs here at a lower temperature. Borehole heat flow measurements confirm spatial variations in the Shikoku Basin that were indicated by short probe surveys. Heat flow variations between topographic highs and lows may be related to fluid convection within the basement. This expedition also included the objectives of the Nankai Trough Submarine LandSLIDE history (NanTroSLIDE) Ancillary Project Letter (APL) and cored at Site C0018 a pile of mass transport deposits on the footwall of the megasplay fault, a major out of sequence thrust that presumably slips coseismically during large subduction earthquakes. This brought new insight on the timing of these mass wasting events and on the deformation within the sliding slope sediments.

Description: The rhyolitic Upper Nisyros Pumice (UNP) from the Kos-Yali-Nisyros volcanic system has been detected as a cryptotephra layer in lacustrine sediments from the Sea of Marmara (SoM). A new independent age of the UNP eruption at 57.1 ± 1.5 cal ka BP has been interpolated using a combination of radiocarbon dating, tephrochronology and wiggle-matching of the SoM proxy record (Ca-curves) with Greenland oxygen isotope data, therewith confirming recently published radioisotopic dates of UNP land deposits. The UNP tephra in the SoM was identified by comparisons of the SoM tephra glass chemical dataset with published data of other marine tephra records from the Aegean Sea and the Megali Limni lacustrine sediment sequence (Lesvos Island). The stratigraphic position of the UNP tephra in these records verified its deposition in the SoM at the onset of MIS-3 and specifically at the termination of Greenland Interstadial GI-16. The new findings define the UNP tephra as a valuable time marker for the synchronisation of palaeoenvironmental data for this time period and help spurring the establishment of a robust tephrostratigraphical framework for the last ∼70 kyr in the Aegean-Black Sea region.

Description: Data Terra’s main mission is to develop a structure for accessing and processing data, data-products and services geared towards observing, understanding and predicting in an integrated manner the history, mechanisms and evolution of the Earth system in response to global changes and extreme events. Data Terra federates four data and services hubs dedicated to the four physical compartments of the Earth System: Aeris for the atmosphere, Odatis for the oceans, Theia for land surfaces and ForM@Ter for the solid Earth. While aimed chiefly at the scientific community, the unique research e-infrastructure also serves public and socio-economic stakeholders and its multi-source data are accessible via coherent, one-stop portals. As a digital infrastructure in the field of earth and environmental science, Data Terra works closely with Earth-observation research infrastructures and space agencies. It is backed by a continuum of distributed and interconnected platforms, proposing services that span the full data cycle from access from repositories to value-added processing, thus enabling inter- and trans-disciplinarity studies as well as exploitation of large volumes of data. At national, European and international levels (EOSC Pillar, Fair impact, Phidias, Copernicus services, …), it is advancing the development of open science, implementation of FAIR approaches, contributing to space missions and applications and to the initiative to generate digital twins of the Earth. Data Terra federates four data and services hubs dedicated to the four physical compartments of the Earth System: Aeris for the atmosphere, Odatis for the oceans, Theia for land surfaces and ForM@Ter for the solid Earth. While aimed chiefly at the scientific community, the unique research e-infrastructure also serves public and socio-economic stakeholders and its multi-source data are accessible via coherent, one-stop portals. Data Terra’s main mission is to develop a structure for accessing and processing data, data-products and services geared towards observing, understanding and predicting in an integrated manner the history, mechanisms and evolution of the Earth system in response to global changes and extreme events. Data Terra federates four data and services hubs dedicated to the four physical compartments of the Earth System: Aeris for the atmosphere, Odatis for the oceans, Theia for land surfaces and ForM@Ter for the solid Earth. While aimed chiefly at the scientific community, the unique research e-infrastructure also serves public and socio-economic stakeholders and its multi-source data are accessible via coherent, one-stop portals. As a digital infrastructure in the field of earth and environmental science, Data Terra works closely with Earth-observation research infrastructures and space agencies. It is backed by a continuum of distributed and interconnected platforms, proposing services that span the full data cycle from access from repositories to value-added processing, thus enabling inter- and trans-disciplinarity studies as well as exploitation of large volumes of data. At national, European and international levels (EOSC Pillar, Fair impact, Phidias, Copernicus services, …), it is advancing the development of open science, implementation of FAIR approaches, contributing to space missions and applications and to the initiative to generate digital twins of the Earth.