High-resolution stratigraphy of a Quaternary fluvial deposit based on magnetic susceptibility variations (J aszs ag Basin, Hungary) ZOLT  AN P € USP € OKI, T  IMEA FOGARASSY-PUMMER, EDIT THAM  O-BOZS  O, BERNADETT BER  ENYI,  AGNES CSERK  ESZ-NAGY, B  ALINT SZAPPANOS, EM } OM  ARTON, ZOLT  AN LANTOS, ANNAM  ARIA N  ADOR, TAM  AS FANCSIK, FERENC STERCEL,  AGNES T  OTH-MAKK, RICHARD W. MCINTOSH, TEOD  ORA SZ } OCS AND ENIK } O FARAG  O P€ usp€ oki, Z., Fogarassy-Pummer, T., Tham o-Bozs o, E., Ber enyi, B., Cserk esz-Nagy,  A., Szappanos, B., M arton, E., Lantos, Z., N ador, A., Fancsik, T., Stercel, F., T oth-Makk,  A., McIntosh, R. W., Sz} ocs, T. & Farag o, E.: High- resolution stratigraphy of a Quaternary fluvial deposit based on magnetic susceptibility variations (J aszs ag Basin, Hungary). Boreas. https://doi.org/10.1111/bor.12412. ISSN 0300-9483. Quaternary fluvial succession of the J aszs ag Basin (Hungary) was investigated, challenging the stratigraphical potential of ‘early postglacial fluvial magnetic susceptibility episodes’ recognized earlier in the K€ or€ os Basin. Low field magnetic susceptibility (MS) was measured in four boreholes from the basin centre and margins, representing channel and flood-plain environments. Statistical distributions of MS data contain significant sets of outliers, regardless of facies conditions. The downhole distribution of these outliers produces magnetic susceptibility cycles. Supported by magnetic susceptibility cycles, high-resolution facies correlations were performed reflecting a steady palaeohydro- graphical situation in the area, with a trunk river to the southeast and tributaries to the northwest. SEM-EDX data revealed that ferromagnetic grains are responsible for the outlying MS values. The heterogeneous association of magnetite indicates a catchment area with volcanic and metamorphic rocks, while the group of small (<5 lm) magnetite octahedrons originated from nearby rhyolitic tuff formations. Magnetic grainswere transported along channel belts, while small (<2 lm) magnetic particleswere floated onto flood-plains attached to clays. Climatic control is indicated by peaks at ~100 ka frequency in spectra of MS records andwas also detected in palaeosol development and in flood frequency using the spectra of measured colour (~100 ka) and logged resistivity (~100 ka, ~41 ka),respectively. The climate-dependent MS signal traceable far into the basin in both channel and flood-plain environments can be summonedwhen the Quaternary fluvial succession of the Pannonian Basin is investigated, assuming some sources of magnetite in the catchment areas. According to the concept of ‘fluvial magnetic susceptibility episodes’, the early postglacial escape and spreading of the magnetite fraction control the MS signal that can support mapping of the unconformable Quaternary base and building of high-resolution models of aquifers. Zolt anP€ usp€ oki(puspoki.zoltan@mbfsz.gov.hu),T  ımeaFogarassy-Pummer,EditTham o-Bozs o,  Agnes Cserk esz-Nagy, Em} oM arton, Zolt an Lantos, Annam aria N ador, Tam as Fancsik, Ferenc Stercel,  Agnes T oth-Makk and Teod ora Sz} ocs, Mining and Geological Survey of Hungary, Stef ania  ut 14, Budapest H-1143, Hungary; Bernadett Ber enyi, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tud osok k€ or utja 2, Budapest H-1117, Hungary; B alint Szappanos, Hungarian Malacological Society, Stef ania  ut 14, Budapest H-1143,Hungary; Richard W. McIntosh, Enik} o Farag o, Department of Mineralogyand Geology, University of Debrecen, Egyetem t er 1, Debrecen H-4032, Hungary; received 22nd March 2019, accepted 23rd August 2019. The application of high-resolution stratigraphical inves- tigations to fluvial deposits, especially in intra-continen- tal settings is a concern due to frequent facies changes, unconformities, and the lack of palaeontological data. The Great Hungarian Plain in the Pannonian Basin (Fig. 1A) is an important Quaternary intra-continental fluvial region in Europe. As the main reservoir of national drinking water reserves, it’s several hundred metres thick sedimentary succession (Fig. 1B) has been a key focus for Hungarian Quaternary geological and hydrogeological research since the early 20th century (reviewed by G abris & N ador (2007) and references therein, and also by Urbancsek (1960) and Erd elyi (1964, 1971, 1972)). Stratigraphical investigations were supported by a set of fully cored boreholes (Fig. 1B; R onai 1985). To establish a correlation with global chronology, two of these boreholes, representing the most complete Qua- ternary sequences (D evav anya, V eszt} o), were dated magnetostratigraphically (Cooke et al. 1979). Magnetic susceptibility (MS) records from these boreholes were correlated with the marine isotope record (Shackleton et al. 1990) revealing Milankovitch-scale cycles (N ador et al. 2003). The MS records of boreholes in the K€ or€ os Basin were correlated by P€ usp€ oki et al. (2016) with each other and with the MS record of the Chinese Loess sequence published by Ding et al. (2005) referred to also by Gibbard & Cohen (2008). P€ usp€ oki et al. (2016) revealed that MS records can provide a ~100-ka resolution stratigraphical tool in the Quaternary fluvial succession of the basin. As a result, the concept of ‘orbitally controlled early postglacial fluvial magnetic susceptibil- ity episodes’ was established, concluding that early postglacial warming periods are clearly shown in the fluvial succession by the occurrence of conspicuous MS maxima. According to the proposed physical model, the fluvial MS record is determined by the climatic control on the delivery and preservation of magnetic minerals, mainly magnetite. Under cold-and-dry climate these minerals were released from solid rocks owing to frost shattering in the adjacent hinterlands and were trans- ported to alluvial plains in the early postglacial periods thanks to the increasing discharge of rivers. With further DOI 10.1111/bor.12412 © 2019 Collegium Boreas. Published by John Wiley & Sons Ltd