Palaeoenvironmental implications from Lower Volga loess - Joint magnetic fabric and multi-proxy analyses

Költringer, Chiara; Bradák, Balázs; Stevens, Thomas; Almqvist, Bjarne; Banak, Adriano; Lindner, Martin; Kurbanov, Redzhep; Snowball, Ian

doi:10.1016/j.quascirev.2021.107057

Cited by 19 publications

(9 citation statements)

References 45 publications

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“…The oblate shapes of the Ulantatal AMS ellipsoids are typical features of loess deposits and are commonly related to the dominance of phyllosilicates and gravitational depositional environments (e.g., Bradák et al., 2020; Költringer et al., 2021; Lagroix & Banerjee, 2002; Taylor & Lagroix, 2015; Zhu et al., 2004). Many Ulantatal samples have non‐vertical K min inclination and, in general, comparatively scattered AMS ellipsoid orientations.…”

Section: Discussionmentioning

confidence: 99%

“…As such, we filter our data in order to (a) identify the primary depositional fabric and (b) pinpoint statistically significant anisotropy in individual datapoints, which may be indicative of dust transporting wind directions. We utilize the following specimen acceptance criteria (Hus, 2003; Költringer et al., 2021; Lagroix & Banerjee, 2004; Zhu et al., 2004) to achieve this: (a) Statistically significant F , defined by F 23 > 10, vertical K min (inclination >70°), and subhorizontal K max is present; (b) Statistically significant L , defined by F 12 > 4 and E 12 < 20° is present; (c) F is clearly higher than L and has similar trend to P j when plotted against depth (→ F controls the shape of the AMS ellipsoid); (d) The shape of the AMS ellipsoid is oblate ( T > 0). (e) Stereoplot analysis and the principal susceptibility axes indicate gravity controlled and flow‐aligned MF on a horizontal depositional plane.…”

Section: Methodsmentioning

confidence: 99%

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Modern‐Type Eolian Regime and Global Cooling‐Modulated Dust Provenance in the Late Paleogene of Central‐East Asia

Bohm,

Wasiljeff,

Stevens

et al. 2024

Geochem Geophys Geosyst

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Atmospheric mineral dust is a poorly constrained yet extremely important component of the climate system. Provenance studies from geologic dust archives are crucial to understand the drivers of the dust cycle over long time scales. Our multi‐technique provenance analysis of a rare Paleogene (35–27 Ma) eolian dust sequence from Ulantatal, ∼400 km northwest of the Chinese Loess Plateau (CLP), shows that Paleogene dust transporting winds generally varied between northwesterly and westerly, the same as those in the late Neogene‐Quaternary bipolar icehouse. We propose that, as today, westerly wind circulation patterns would have been modulated by an Arctic Oscillation (AO)‐like situation, and that the warm Eocene favored a long‐term negative phase of AO, leading to meridional westerly circulation and the dominance of a northwesterly dust transport pathway. After the Eocene‐Oligocene transition (EOT), long‐term positive phase of AO‐like conditions initiated, leading to stronger and more zonal westerlies. The Siberian High (SH) also formed or strengthened at the EOT and started to control dust storm activity along the northwesterly transport pathway. We argue that increased Paleogene Northern Hemisphere (NH) ice volume was the ultimate driver of this modern‐type dust transport regime in the Ulantatal region, possibly also controlling initial Ulantatal dust sequence formation via the development of the SH and modern‐type eolian regime. The similarity between the Ulantatal and late Neogene northern CLP dust provenance signals suggests that the increased NH ice volume, via its control on the northwesterly dust transport, could have promoted increased loess formation also in the late Miocene.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Modern‐Type Eolian Regime and Global Cooling‐Modulated Dust Provenance in the Late Paleogene of Central‐East Asia

Bohm,

Wasiljeff,

Stevens

et al. 2024

Geochem Geophys Geosyst

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“…Mineral magnetism is widely used in studies of loess deposits, to understand past climate, landscape and postdepositional reworking conditions (e.g. Oches & Banerjee, 1996;Költringer et al, 2021aKöltringer et al, , 2021bBradák, 2009;Bradák et al, 2011). In particular, the magnetic susceptibility of loess, and its frequency dependence, is widely used as a proxy for past soil formation.…”

Section: Introductionmentioning

confidence: 99%

Mineral magnetism and palaeoenvironment recorded in loess in southern England

Niezabitowska,

Stevens,

Bradák

et al. 2024

J Quaternary Science

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Extensive research has focused on the loess deposits in southern England, aiming to unravel their stratigraphic and palaeoenvironmental significance. However, no systematic mineral magnetic study on these deposits has yet been undertaken. Here we address this by investigating the magnetic mineral composition and alignment of loess at two sites in southern England, Lowland Point (LP) on the Lizard Peninsula of Cornwall, and Pegwell Bay (PB) in eastern Kent on the Isle of Thanet. A set of rock magnetic analyses was conducted to understand mineral magnetism within the studied sections. In addition, the primary depositional origin of the magnetic fabrics as well as their overprinting caused by various possible post‐depositional processes were examined through anisotropy of magnetic susceptibility (AMS). The magnetic mineral composition is similar at both sites, derived from both sedimentary (aeolian) and post‐depositional processes. The AMS results show magnetic foliation that varies between the two sites, aligning with the bedding plane, indicating deposition from gravitational dust fall at the PB site, and a stronger wind transport energy at the LP site. Although the magnetic lineation of bulk AMS is relatively weak, there is a noticeable tendency towards alignment in most samples, with flow directions from the SE indicated at both sections if a strong wind is assumed at LP, although with a possible SW direction if a weaker wind is assumed. These observations may imply the preservation of palaeowind directions during dust transport, with a substantial southerly component, which contradicts previous assertions of dominant northerly or northeasterly winds. Indeed, a possible dominant southeasterly wind direction between 25 and 18 ka would suggest a limited influence of katabatic, westerly or polar northeasterly winds during dust transport, and rather may imply the effect of low‐pressure systems passing through the English Channel during that period.

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“…Rock magnetism (magnetic properties of rocks) and palaeomagnetic (magnetostratigraphy) methods, especially in combination with lithological-palaeopedological and palynological analyses, serve as a powerful tool in the reconstruction of palaeoenvironmental changes [120][121][122]. Magnetic susceptibility is a sensitive, fast and accurate technique to detect soil pedogenic processes and features and can improve the understanding of soil-forming and, correspondingly, palaeoclimate factors [86,[123][124][125][126][127][128][129][130][131][132][133][134][135][136][137][138][139][140].…”

Section: Introductionmentioning

confidence: 99%

Early–Middle Pleistocene Magnetostratigraphic and Rock Magnetic Records of the Dolynske Section (Lower Danube, Ukraine) and Their Application to the Correlation of Loess–Palaeosol Sequences in Eastern and South-Eastern Europe

Hlavatskyi

Бахмутов

2021

Quaternary

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We present new palaeomagnetic and rock magnetic results with a stratigraphic interpretation of the late Early–Middle Pleistocene deposits exposed on the left bank of the River Danube at Dolynske, southern Ukraine. A thick succession of water-lain facies is succeeded by reddish-brown clayey soils, topped by a high-resolution loess–palaeosol sequence. These constitute one of the most complete recently discovered palaeoclimate archives in the Lower Danube Basin. The suggested stratigraphy is based on the position of the Matuyama–Brunhes boundary, rock magnetic, palaeopedological and sedimentological proxies, and it is confidently correlated with other loess records in the region (Roksolany and Kurortne), as well as with the marine isotope stratigraphy. The magnetic susceptibility records and palaeosol characteristics at Dolynske show an outstanding pattern that is transitional between eastern and south-eastern European loess records. Our data confirm that the well-developed S4 soil unit in Ukraine, and S5 units in Romania, Bulgaria and Serbia, correlate with the warm MIS 11. Furthermore, we suggest the correlation of rubified S6 palaeosols in Romania and Bulgaria and the V-S7–V-S8 double palaeosol in Serbia with S6 in Ukraine, a strong Mediterranean-type palaeosol which corresponds to MIS 15. Our new results do not support the hypothesis of a large magnetic lock-in depth like that previously interpreted for the Danube loess, and they prove that the Matuyama–Brunhes boundary is located within the palaeosol unit corresponding to MIS 19. The proposed stratigraphic correlation scheme may serve as a potential basis for further regional and global Pleistocene climatic reconstructions.

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Palaeoenvironmental implications from Lower Volga loess - Joint magnetic fabric and multi-proxy analyses

Cited by 19 publications

References 45 publications

Modern‐Type Eolian Regime and Global Cooling‐Modulated Dust Provenance in the Late Paleogene of Central‐East Asia

Modern‐Type Eolian Regime and Global Cooling‐Modulated Dust Provenance in the Late Paleogene of Central‐East Asia

Mineral magnetism and palaeoenvironment recorded in loess in southern England

Early–Middle Pleistocene Magnetostratigraphic and Rock Magnetic Records of the Dolynske Section (Lower Danube, Ukraine) and Their Application to the Correlation of Loess–Palaeosol Sequences in Eastern and South-Eastern Europe

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