Lithopetrographic and geochemical features of the Saalian tills in the Szczerców outcrop (Poland) in various deformation settings

Abstract

This paper presents the results of new studies of Saalian tills, from the Ławki and Rogowiec formations, filling the Kleszczów Graben. The study area is located in the Szczerców outcrop, Bełchatów Lignite Opencast Mine, central Poland. Laboratory studies included macrofossil analysis of the deposits, as well as petrographic and geochemical (neodymium isotope ratio) measurements. The studies were carried out in 2014–2016 and resulted in both establishing the sedimentary Saalian complex and constructing geological cross-sections and a synthetic lithostratigraphic profile. Development of sediments in this part of the Kleszczów Graben in the Pleistocene was largely influenced by tectonic factors (Chabielice fault, Dębina Salt Dome) and glacitectonic processes (Wartanian Glaciation). The Saalian tills (T4 – Ławki and T7 – Rogowiec lithotypes) are between the Holsteinian sand with macroremnants of trees and the Eemian gyttja and peat. Petrographic coefficients for lithotype T4 (Ławki Formation) are 1.33–1.06–1.01 and 0.12 and for lithotype T7 (Rogowiec Formation) are 1.29–1.23–1.04 and 0.12. Investigations of the Nd isotopic compositions of the studied samples reinforce our interpretations of till deformation and tentative lithostratigraphic correlations. Neodymium isotope ratios “P” (−14.4 ± 0.7) and “D” (−12.4 ± 0.3) ε Nd values (2σ) correspond to mean signatures of Saalian glacigenic moraine sediment. This proves that ε Nd values less than −12.4 reflect the southern Fennoscandian Ice Sheet sediment provenance, but ε Nd values greater than −12.4 indicate the western European origin.

Environmental changes during the MIS 6a–MIS 5e transition: the Parchliny 2016 profile, central Poland

“…13). How ever, they were not filled with min eral sed i ments, be cause no such de pos its have been found (Wachecka-Kotkowska et al, 2021). Hence, we con clude that the de pos its must have been in cor po rated into the drain age sys tem quite quickly.…”

“…The tills contain many lig nite clasts. The lithological/petrographic in di ces are as fol lows: O/K = 0.81; K/W = 1.69; A/B = 0.70; D/LPI = 0.11 (Wachecka-Kotkowska et al, 2021). At the top of the till, there is a thin gravel/boul der pave ment and in di vid ual ventifact pebbles, a tree bough, and tree branch re mains were found (Fig.…”

“…The base ment of the Parchliny 2016 pro file is com posed of dis turbed gla cial tills that were ob served lo cally at the bot tom of subglacial chan nels or melt-out ket tles. The lithologicalpetrographic ex am i na tion of the tills sug gests that it is lithotype T4, which cor re sponds to the £awki For ma tion (Wachecka-Kotkowska et al, 2021). How ever, in a typ i cal se quence, we would ex pect one of the youn ger lithotypes, such as lithotype T7 (cf.…”

“…The el e va tion of the ground sur face in this area, be fore ex ca va tion com menced, was ~178-181.5 m a.s.l. At the base of the pro file, there was the Odranian gla cial till layer (£awki and Rogowiec For ma tions, see Allen and Krzyszkowski, 2008;Wachecka-Kotkowska et al, 2021), cur rently as so ci ated with the Warta Stadial (MIS 6a). Above the pro file stud ied, the thickness of the lake de pos its (Aleksandrów Fm., Eemian) was ~4-6 m; how ever, these were lo cated on a very steep part of the wall and are be yond the scope of this work.…”

“…The Parchliny 2016 pro file and its bed rock have been described in lithological/petrographic terms. These are O/K, K/W A/B, and D/LPI (O -to tal of sed i men tary rocks; K -to tal of crystal line rocks; W -to tal of car bon ate rocks; A -to tal of non-re sistant rocks; B -to tal of re sis tant rocks; see Wachecka- Kotkowska et al, 2021). The in di ces used are in ac cor dance with, the stan dard spec i fied by the Pol ish Geo log i cal In sti tute -Na tional Re search In sti tute in War saw (Marks and Ber, 1999).…”