High-resolution palaeomagnetic record from Sea of Marmara sediments for the last 70 ka

• Published in: Geophysical Journal International
• Main Authors: Makaroğlu, Özlem, Nowaczyk, Norbert R., Eris, Kadir Kürşad, Çağatay, M. Namık
• Other Authors: İÜC, Mühendislik Fakültesi, Jeofizik Mühendisliği Bölümü
• Format: Article in Journal/Newspaper
• Language: English
• Published: Oxford Univ Press 2020
• Subjects: Geomagnetic excursions; Marine magnetics and palaeomagnetics; Palaeointensity; Palaeomagnetic secular variation; Palaeomagnetism; Greenland; Greenland ice core; ice core
• Online Access: https://doi.org/10.1093/gji/ggaa281; https://hdl.handle.net/20.500.12831/2203

WOS:000565895200035 Magnetostratigraphic and geochemical analyses were performed on two sediment cores recovered from the Sea of Marmara to investigate geomagnetic field variations over the last 70 ka. A chronology for each of the two cores was developed from eight AMS C-14 datings, tephrochronology, and tuning of Ca concentrations with stadials and interstadials observed in Greenland ice core oxygen isotope data. Based on the age models, cores MD01-2430 and MRS-CS19 reach back to 70 and 32 ka, respectively. High average sedimentation rates of 43 cm kyr(-1) for core MD01-2430 and 68 cm kyr(-1) for core MRS-CS19 allow high-resolution reconstruction of geomagnetic field variations for the Sea of Marmara. Mineral magnetic properties are sensitive to glacioeustatic sea level changes and palaeoclimate variations in this region, reflecting the variable palaeoenvironmental conditions of the Sea of Marmara during last 70 ka. Despite the impairment of the palaeomagnetic record in some stratigraphic intervals due to early diagenesis, relative palaeointensity variations in the Sea of Marmara sediments correlate well with similar records derived from other regions, such as the nearby Black Sea and the GLOPIS-75 stack. The directional record derived from the Sea of Marmara cores exhibits typical palaeosecular variation patterns, with directional anomalies at 41 and 18 ka, representing the Laschamps and postulated Hilina Pali excursions, respectively. Both directional anomalies are also associated with palaeointensity minima. A further palaeointensity minimum at 34.5 ka is likely related to the Mono Lake excursion, with no directional deviation documented in the Sea of Marmara palaeomagnetic record so far. Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [115Y773]; Deutscher Akademischer Austauschdienst (DAAD)Deutscher Akademischer Austausch Dienst (DAAD) [57210259] This study was supported by the Scientific and Technological Research Council of Turkey (TUBITAK 115Y773) and the Deutscher Akademischer Austauschdienst (DAAD Funding 57210259). We thank Pierre Henry for supporting work on core MRS-CS19 and Frank Bassinot for sampling of core MD01-2430 at CNRS, Gifsur-Yvette. We thank Nurcan Kaya, Melda Kucukdemirci, Mumtaz Hisarli,.Idil Urla, Gulay Isguder and the EMCOL group for technical and logistical help during core processing and sampling. The authors also thank Andrew Roberts and the anonymous reviewer for their constructive comments that improved the paper.