Factors affecting thickness and frequency of turbidites triggered by earthquakes in Kumburgaz Basin, Sea of Marmara

Nurettin Yakupoğlu*, Pierre Henry, Gülsen Uçarkuş, K. Kadir Eriş, François Demory, Christian Crouzet, M. Namık Çağatay

*Bu çalışma için yazışmadan sorumlu yazar

Araştırma sonucu: ???type-name???Makalebilirkişi

4 Atıf (Scopus)

Özet

Submerged fault ruptures generate earthquake-triggered mass flow deposits, which are extensively used as a tool in subaqueous paleoseismology. In tectonically active deep sedimentary basins, such as the Sea of Marmara (SoM), these mass flow deposits are defined as turbidite-homogenite units (THUs), consisting essentially of a coarse basal part and an overlying homogeneous mud (homogenite). Detailed characterization of THUs is crucial in order to establish meaningful criteria to link these units with earthquakes events and to identify their transport routes and depositional mechanisms. Here, we combine μ-X-ray Fluorescence (μ-XRF), Anisotropy of Magnetic Susceptibility (AMS) and additional rock magnetism analyses of a 21-m long piston core from the Kumburgaz Basin of SoM to define the upper stratigraphic boundary of THUs with hemipelagic sediments and investigate the controls of hydrological changes on turbidite frequency and thickness over the last 15 kyrs BP. The sedimentary succession of this period includes a lower lacustrine and an upper marine unit with two Holocene sapropel intervals. The sequence is interrupted by a total of 70 THUs, characterized by a significant magnetic foliation related to the depositional setting rather than the magnetic signature. Magnetic mineralogy of the coarse basal parts of THUs have more ferromagnetic particles than the overlying homogenites and background sediments. While the homogenite parts have a more constant mineralogy than the basal parts, they do not differ the background sediments. Based on an event-free chronostratigraphic model derived from radiocarbon ages and the published age of lacustrine-marine (L-M) transition, the average THU occurrence intervals in the lacustrine (14.8–12.6 kyrs BP), lower sapropel (11.2–5.7 kyrs BP), upper sapropel (5.4–2.7 kyrs BP) and non-sapropelic part of the marine unit (2.7 kyrs BP-present) are 235 yrs., 287 yrs., 114 yrs. and 160 yrs. respectively. The average thickness of the THUs in the same units are 20.8 cm, 15.7 cm, 6.1 cm and 6.1 cm. The variability of average THU occurrence intervals and THU thicknesses are controlled by the sea level rise and salinity increase following the full marine connection of the SoM at 12.6 kyrs BP, which caused changes in slope stability, sediment composition and sediment deposition in different parts of the basin. Geomechanical properties of the lower sapropel appears to have been important in resulting long THU recurrence intervals and relatively high THU thicknesses.

Orijinal dilİngilizce
Makale numarası106900
DergiMarine Geology
Hacim452
DOI'lar
Yayın durumuYayınlandı - Eki 2022

Bibliyografik not

Publisher Copyright:
© 2022 Elsevier B.V.

Finansman

This study is part of Nurettin Yakupoğlu's PhD Dissertation. Cores were taken during MARSITECRUISE of Ifremer/Genavir R.V.Pourquoi Pas?, within the framework of MARSITE FP7 EU Project (grant agreement no.: 308417 ). Financial support was provided by the bilateral ANR/TUBITAK collaborative research project MAREGAMI ( ANR-16-CE03-0010-02 and Tubitak Project 116Y371 ). Part of this work has been supported by TÜBİTAK 1002 project ( 118Y057 ) and ITU BAP project ( MDK-2020-42743 ). All geochemical and sedimentological analyses were performed in ITU EMCOL laboratories.

FinansörlerFinansör numarası
TÜBİTAK 1002 project118Y057
Seventh Framework Programme308417
International Technological UniversityMDK-2020-42743
Türkiye Bilimsel ve Teknolojik Araştırma KurumuANR-16-CE03-0010-02, 116Y371

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