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Patterns, processes and models – an analytical review of current ambiguous interpretations of the evidence for pre-Pleistocene glaciations

Molén Mats O.

Geologos

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2023

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Vol. 29, No. 3

139--166

EN

Models (paradigms) and former interpretations have often been presupposed when conducting field research. In the 19th century diamictites were for the first time interpreted to have originated from ancient glaciations. These interpretations have to a large part prevailed in the geological community, although there has been much progress in the areas of sedimentology, glaciology and physical geography. The present work is an effort to find criteria which most clearly discriminate between geological features produced by different processes, mainly glaciation and mass flow, the latter predominantly sediment gravity flows. Geological features which have been interpreted to have formed by glaciation throughout pre-Pleistocene Earth history are compared to similar-appearing geological features formed by mass flow and tectonics, so as to uncover variations in the appearance between features resulting from these different processes. The starting point for this comparison is documentation of the appearance of Quaternary products of erosion and deposition, in order to discern the origin of older formations. It is shown that the appearance and origin of pavements, dropstones, valleys, small-scale landforms, surface microtextures and most other geological features may in some cases be equivocal, but in others the details are indicative of the process which generated the feature. Detailed geological field data which have been compiled by geologists from outcrops of pre-Pleistocene strata, more often than is considered in most papers, commonly point to a mass flow origin, mainly a sediment gravity flow origin, rather than a glaciogenic or- igin. A process of multiple working hypotheses or interpretations is therefore advocated, based mainly on a comparison of the appearance of features formed by different geological processes documented from different research disciplines. Instead of starting with current interpretations or models, this multiple working hypothesis or methodology helps to avoid confirmation bias and jumping to conclusions.

2

Tarasy Białki w rejonie Jurgowa i ich związki z lodowcami tatrzańskimi

Pliszczyńska K.

Przegląd Geologiczny

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2012

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Vol. 60, nr 2

103-109

EN

The paper presents examination of views on number and age of glaciations in the Tatra Mts. and a new interpretation of palaeogeomorphology of the Białka Valley at Jurgów in the Podhale region (Poland). Author took 20 samples of pebbles (2-10 cm in diameter) from surface of Quaternary terraces. Petrographic analyses (petrographic composition of terrace deposits, weathering degree of granite pebbles and content of cracked granite) were carried out. Results of these analysis were used to estimate the age of terraces. The studies showed presence of four glaciofluvial terraces (VIb-IV) of the Riss 1, Riss 2 and Würm glaciations and three fluvial terraces (III-I) of the Holocene age. The paper also contains a description of probable glacial deposits (lateral moraines?) from the Mindel glaciation.

3

O podziale klimatostratygraficznym kompleksu środkowopolskiego w plejstocenie Polski

Lindner L., Marks L.

Przegląd Geologiczny

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2012

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Vol. 60, nr 1

36-45

EN

The term Middle Polish Complex was introduced by the authors in 2007 as an informal superstage of the younger Middle Pleistocene in Poland. It replaced a previous inconsistent term of Middle Polish Glaciations, composed both of glaciations and interglacials. The Middle Polish Complex comprises deposits of 3 glaciations (Liwiecian, Krznanian and Odranian) and 3 interglacials (Mazovian, Zbójnian and Lublinian). Glacial and lake-marshy deposits of the complex correspond with loess sequences and separating palaeosols. Their common superposition in Poland and recorded palaeomagnetic episodes Emperor, Chegan, Jamaica and Blake of the Brunhes epoch verify a chronology of climatic changes and climatostratigraphic subdivision of the complex. Mutual relation of climate changes and their reference to glacial-interglacial and loessy-palaeosol cycles in neighbouring countries support usefulness to more specified correlations. Successive interglacials and glaciations of the Middle Polish Complex correspond to rhythmic global climate changes reflected by oxygen isotope stages in deep-sea boreholes (MIS11-6)

4

Wpływ środkowoplejstoceńskich struktur glacitektonicznych i rynien subglacjalnych na rzeźbę w północnej części Pojezierza Lubuskiego [zachodnia Polska]

Winnicki J.

Przegląd Geologiczny

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2004

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Vol. 52, nr 12

1144--1150

EN

The northern part of Lubusz Lakeland is the area of a various relief, where are clearly marked morphological by varied Ośno-Sulechów Hills and a flat Torzym Plain, situated farther south. Both units are cut by deep valleys used by rivers and lakes. The relief generally arose at the end of South-Polish Glaciations. In the first stage, push moraine[Ośno-Sulechów Hills] formed of folded Paleogene and Neogene and Quaternary sediments. The extent of the vertical Cenozoic sediment movements presumably exceeds 250 m. On the Torzym Plain, there were much less disturbed Paleogene and Neogene sediments in the form of a big beaming folding structures. In spite of the lack of Paleogene and Neogene convincing evidence, it’s not possible to reject tectonic movements during formation Ooeno-Sulechów Hills and Torzym Plain. The younger glaciations modified earlier elements of this relief to a small extent. During the next stage of the South-Polish Glaciations [Sanian] very deep subglacial valleys were eroded, which probably were connected with the drainage system of central and northern Germany. The valleys cut out the subglacial zone of Ośno-Sulechów Hills and Torzym Plain to the depth of over 160 m b.s.l. Those valleys still existed during the next glaciations and interglacials, as indicated by fluvial and lacustrine sediments of Mazovian Interglacial age, as well as valley sandurs of Pliszka and Ilanka rivers originated during the Weichselian.

5

Śląska i wielkopolska prowincja litostratygraficzna glin zwałowych

Czerwonka A. J.

Przegląd Geologiczny

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2004

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Vol. 52, nr 5

421-–429

EN

The paper introduces a semiformal term “glacial till lithostratigraphical provinces” to denote geographical areas of occurrence of lithological groupings and formations of glacial tills. Within the area between Noteć River ice-marginal valley and the Sudetic Foreland, 23 types of tills were recognized. Of these, 15 lithotypes were included into the Great Poland till province, four were included into the Silesian province, while the remaining ones, found at the eastern periphery of the Kraków-Częstochowa Highland are preliminarily assigned to another, not yet defined province situated east of the study area. Maps illustrating distribution of particular lithotypes were made and served as a basis for an attempt to reconstruct the changes in ice-sheet extent during subsequent glaciations.

6

Początek późnopaleozoicznego zlodowacenia Gondwany i jego zapis w polskich sukcesjach karbońskich

Skompski S.

Przegląd Geologiczny

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2003

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Vol. 51, nr 8

658-662

PL

Z porównania metod bezpośredniego i pośredniego datowania karbońskiego początku zlodowacenia Gondwany wynika, że najpewniejszym wskaźnikiem tego zdarzenia jest pojawienie się na południowym szelfie Laurussii specyficznego typu kontrolowanej glacieustatycznie sedymentacji cyklicznej. Spośród licznych obszarów tego szelfu z dobrze rozpoznanym zapisem sedymentacji względnie stabilne tektonicznie były obszary basenu lubelskiego i basenu Illinois (w przeciwieństwie np. do obszaru brytyjsko-belgijskiego i dnieprowsko-donieckiego). Analiza cykliczności w tych dwóch obszarach wskazuje, że początek zlodowacenia miał miejsce w brygancie (późny wizen). Wcześniejsza sedymentacja krótkookresowych cyklotemów (o przeciętnym okresie 100 000 lat), które pojawiły się w asbie, była prawdopodobnie wywołana przyczynami natury tektonicznej.

EN

Two specimens of Oslo rhomb porphyries find on the Wolin Island beach between Międzyzdroje and Grodno are extraordinary finds among the entire population of Scandinavian indicator erratics within glacial sediments in northern Poland. Only around 20 localities of erratics from Oslo have been noted in that part of Poland so far (Schulz, 1973). Unfortunately, the stratigraphy of the Wolin erratics is not known, because they have been found on the stony abrasion shelf at the foot of a cliff. The cliff itself consists of two separate till layers. The petrographical analysis of the lower bed of gray glacial till where rhomb porphyries had been found, point to distinctly north-western direction of an ice sheet advance (50 % of the entire population of erratics from sample 3 derive from western mother regions in the southern Baltic bottom). The analysed indicator erratics form the lower Wolin till represent the south-eastern Sweden and western part of the bottom of Baltic depression. The ice-sheet, approaching from the north, has transgressed on these outcrops before reaching the mother regions of Cretaceous limestones, which are located in the direct vicinity of the Wolin Island. The ample content of western erratics in sampled sediments of the Wolin cliff as well as the Oslo rhomb porphyries are of high interest. Have they come in icebergs (Benn & Evans, 1998, see Donner, 1995) or maybe their presence in glacial sediments should be connected with the Lagerlund's ice dome (1987, 1995)7 Schulz (2003) suggests a ship transport (as ballast stones). The planned detailed petrographical analysis on the Scandinavian erratics of the Wolin cliff should clarify the issue.

7

Główne cykle klimatyczne w stratygrafii plejstocenu Polski i Ukrainy

Lindner L., Bogucki A., Marciniak B., Marks L., Łanczont M., Wojtanowicz J.

Przegląd Geologiczny

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2002

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Vol. 50, nr 9

787-792

PL

Przedstawiono zasady korelacji stratygraficznej 11 plejstoceńskich cykli glacjalno-interglacjalnych i lessowo-glebowych (od A do K) na obszarze Polski i Ukrainy. Stwierdzono zgodny rytm zmian klimatycznych w strefie pomiędzy Morzem Bałtyckim a Morzem Czarnym. Jednostki glacjalne i interglacjalne wyróżniane w Polsce odniesiono do sekwencji lessowych z glebami kopalnymi na Ukrainie. Analiza liczby i czasu trwania tych cykli potwierdza możliwość ich korelacji z cyklami astronomicznymi w przedziale 110-90 tysięcy lat. Podczas starszych cykli (od F do K) możliwa jest obecność większej liczby zlodowaceń i interglacjałów niż się dotychczas przyjmuje. W pierwszej kolejności może to dotyczyć sugestii wyodrębnienia ochłodzenia (zlodowacenia?) w interglacjale ferdynandowskim, a w dalszej kolejności pełniejszego dokumentowania ochłodzeń (zlodowaceń?) i ociepleń (interglacjałów) w interglacjałach małopolskim i podlaskim. Możliwość grupowania 2-3 plejstoceńskich cyklów klimatycznych w odrębne megacykle, wiąże się najprawdopodobniej z tym, że czas trwania niektórych cykli mógł się nieco różnić z racji obejmowania przez nie zarówno krótszych interglacjałów (np. eemskiego) jak również krótszych zlodowaceń (np. liwca). Taka identyfikacja megacyklów klimatycznych może także nawiązywać do koncepcji grupowania niektórych zlodowaceń plejstoceńskich w megaglacjały oraz stwarzać podstawy dla ich lepszego nawiązania do klasycznego schematu zlodowaceń alpejskich.

EN

Presented are main principles for stratigraphic correlation of 11 Pleistocene glacial-interglacial and loessy-palaeosol cycles (from A to K) in Poland and in the Ukraine. Concordant rhythm of climatic changes in the territory between the Baltic Sea and the Black Sea was found. Glacial and interglacial units in Poland were correlated with loess sequences and palaeosols in the Ukraine. Number and duration of the detected cycles support their possible correlation with astronomic cycles, 110-90 kyr long. More glaciations and intervening interglacials are to be found for the older cycles (from F to K). There is a distinct cooling (glaciation?) within the Ferdynandovian Interglacial as well as coolings (glaciations?) and warmings (interglacials) within the Malopolanian and Podlasian Interglacials. Some cycles could be shorter or longer if they comprised shorter interglacials (e.g., Eemian) or glaciations (e.g., Liviecian) and therefore, two or three climatic cycles can be grouped into separate megacycles. Such climatic megacycles could be referred more closely to the complex glaciations (megaglaciations). The approach presented in the paper may also enable closer correlation with the classical Pleistocene glacial epochs in the Alps.

8

Glacials, interglacials and ice covers

Stankowski Wojciech

Geologos

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2000

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Vol. 5

189--195

EN

A stratigraphic approach to the Quaternary which takes into account the changes in climate (Pleistocene cold stages = glacials, and Pleistocene warm stages = interglacials, with considerable variations in temperature and humidity), and appearance and disappearance of ice sheets in certain areas. Reduced ice sheets might have remained during the interglacials.