Enviromagnetic study of Late Quaternary environmental evolution in Lower Volga loess sequences, Russia

Abstract

The late Quaternary development of the Lower Volga region of Russia is characterized by an alternating influence of marine and continental environments resulting from fluctuations in Caspian Sea level during the last glaciation. However, sediments deposited under continental conditions have received very little research attention compared to the under- and overlying marine deposits, such that even their origin is still in debate. Detailed magnetic mineralogical analyses presented here show clear similarities to loess. The results suggest that climate during the time of loess deposition, the Atelian regression (27–80 ka, MIS 4–3), was dry and cool, similar to the modern-day Northern Caspian lowland. The magnetic properties recorded in the loess-paleosol sequences of the Lower Volga also point to short episodes of potentially more humid and warmer climate during the late Atelian. The new findings in regard to the local Caspian climate and environmental evolution support decreased river discharge from the Russian Plain and Siberian Plain as the dominant factor causing the low Caspian sea level stand during the Atelian, although local-regional climate changes might have had an additional influence.

Significance of the Ukrainian loess-palaeosol sequences for Pleistocene climate reconstructions: rock magnetic, palaeosol and pollen proxies

“…The new advances in rock magnetic methodologies and analytical techniques expand our ability to obtain important information on palaeoenvironmental change, including reconstruction of past geomagnetic field variations and environmental parameters, and understanding the processes of loesspalaeosol magnetic properties formation. Palaeoclimatic studies of the key loess-palaeosol sequences in the Chinese Loess Plateau (CLP), Central Asia, Danube Basin and East European Plain [Heller, Liu, 1984;Kukla et al, 1988;Forster et al, 1994;Jordanova, Petersen, 1999;Evans, Heller, 2001Rousseau et al, 2001;Buggle et al, 2009;Fitzsimmons et al, 2012;Marković et al, 2015;Necula et al, 2015;Bakhmutov et al, 2017;Chen et al, 2018;Song et al, 2018;Sümegi et al, 2018;Költringer et al, 2020;Bradák et al, 2021;Laag et al, 2021 and many others] have shown that rock magnetic palaeoenvironmental proxies, primarily magnetic susceptibility (MS), display strong similarities and can be correlated with the marine oxygen-isotope stages (MIS) [Shackleton et al, 1990;Lisiecki, Raymo, 2005].…”

Late Pleistocene Climate and Dust Source From the Mobarakabad Loess–Paleosol Sequence, Northern Foothills of the Alborz Mountains, Northern Iran

“…Loess sediment in the mid-latitude of Eurasia provides an excellent sedimentary archive for understanding past climate and environmental changes in the continental interior (e.g., Rousseau et al, 2017Rousseau et al, , 2020Fenn et al, 2020;Fitzsimmons et al, 2020;Költringer et al, 2020;Song et al, 2021). In northern Iran, loess deposits are found in the so-called Northern Iranian Loess Plateau (NILP) and along the northern foothills of the Alborz Mountain range (NFAM).…”

Revisiting Late Pleistocene Loess–Paleosol Sequences in the Azov Sea Region of Russia: Chronostratigraphy and Paleoenvironmental Record

“…The inconsistent changes in χ lf with pedostratigraphy, more complex pattern of χ fd %, and noncovariant relationship along the section between these two parameters may indicate that other processes affect the magnetic signal in the Beglitsa section. A recent enviromagnetic study in nearby Lower Volga loess deposits further east of Azov showed that there are also other factors, such as magnetic mineral dissolution by hydromorphic processes (Taylor et al, 2014), magnetic mineral destruction by strong weathering (Baumgart et al, 2013), magnetic mineral alteration induced by weak pedogenesis (Ma et al, 2013), and surface oxidation of coarse magnetic grains (Van Velzen and Dekkers, 1999;Buggle et al, 2014;Buggle et al, 2014;Stevens et al, 2020), controlling the magnetic signal in this region (Költringer et al, 2020). These processes do not always lead to magnetic enhancement but can cause dissolution and magnetic depletion of certain components, depending on the type of soils and the characteristics of the environment in which the paleosol formed (Bradák et al, 2021).…”