Closed depressions in Central Poland are different origin. Two main groups are anthropogenic and natural forms. Many genetic types of the latter can be indentified, e.g.: l. blow-outs accompanying dunes and their complexes; 2. fluvial depressions, e.g. cut-off oxbow lakes at a various stage of decay; 3. karst collapse depressions, both young and largely buried by younger sediments; 4. suffosion steep-walled kettles and gentle hollows; 5. a significant and extensive group of Pleistocene forms in origin of which ice-sheet and permafrost are involved, thus depressions conditioned by: a. irregular glacial accumulation, b. uneven postglaciotectonic surface, c. dead ice melting out, and also from d. degradation of ground ice, e. progressive melting of intrusive ice. The Pleistocene in age depressions commonly occur on till plains and also in the upper sections of dry valleys (Fig. l). Their significance consists, fust of all, in the usefulness of their fillings to palaeogeographical reconstructions. It is the reason for which they were a subject of detailed analyses. Also, an attempt to correlate the results with the existing climatic curves of the Vistulian for Europe and Poland has been made. The interpretation has been based on the studied profiles from closed depressions, supported by palinologic documentation and radiocarbon dates. They are shown in Fig. 2, while the conclusions are presented below. During the Warta ice-sheet recession (150-140 ka BP) the relief of newly deposited tills and of fresh postglaciotectonic surfaces created local base levels in which deposits of wash and solifluction and afterwards mineral-organic sediments accumulated. There processes were retarded somewhat by very poor communities of treeless tundra that changed gradually to a park tundra and a boreal forest corresponding already to the interglacial succession. The Eemian landscape in Central Poland was aboundant in closed depressions. The primary lakes (gyttja, mineral-organic silts) were in the middle and upper Eem transformed into the raised bogs (peats, peat shales). At some places the process of organic sedimentation went 9.n during the Vistulian (Fig. 2 - Rudunki, Krzepczów). The type of sediments as well as the type of plant cover of the fust stadial of Vistulian (VS1) confum the opinion on an increase of humidity and a fall in temperature. The AmersfoortjBrmup warming, about 10000 years, with the mean temperature of July 15-l7°C and pine forest with larch, birch and spruce ~as followed by the second Vistulian stadial (VS2) with the mean values for July slighthy above 5°C. The succeeding interstadial, which in the vicinity of Łódź is called "Rudunki Interstadial" and is correlated with the Odderade, is the final forest episode of the early glacial that lasted for about 60 000 years. Simultanously, the organic accumulation in Rudunki and Krzepczów fmished (Fig. 2).For the Plenivistulian, until the Denekamp, no correlative deposits (naither organic nor mineral) have been found. Only the Krzepczów profile displays the probable fluvial sedimentation. In the other promes the hiatus comprises all Plenivistulian warmings. Form the Denekamp on, a lot of data on deposits and numerous 14C and TL dates are available. The climatic deterioration enabled silts and fine-grained sediments with numerous syngenetic frost deformations to form on slopes and in depressions. The maximum of cold and aridity, with continuous permafrost, occurring in the Leszno and Poznań Phases corresponds with the gravel-stone horizon. It is correlated with the "Beuningen Steinsohle" and dated at 20000-18 000 years BP. During the ice-sheet recession up to the line of Pomeranian moraines thinly-laminated sands and their oversnow facies deposited. With the ice-sheet withdrawal up to the Gardno Phase, there was renewal of aeolian activity, which has an equivalent at the top of 'deposits of some depressions. The succession observed at the Rudunki site (Fig. 3) is a case in point. However, other facies, e.g. on interlluves or in river valleys, can exist.
PL
Omówiono genetyczne typy zagłębień bezodpływowych najczęściej występujących w środkowej Polsce. Podkreślono dużą, ale zróżnicowaną rolę rodzaju ich wypełnień dla rekonstrukcji paleogeograficznych. za najważniejsze uznano kopalne dziś zagłębienia wieku plejstoceńskiego. Wybrane spośród nich przykłady pochodzące z własnych badań, z dobrze udokumentowanymi osadami wypełniającymi, poddano dokładnej analizie, zwracając szczególną uwagę na sedymentologiczne cechy osadów mineralnych, paleobotaniczną charakterystykę serii organicznych oraz korelacje z wynikami pomiaru wieku bezwzględnego, uzyskanymi metodami 14C i TL. Na podstawie tych danych podjęto próbę rekonstrukcji paleogeograficznej zmieniających się warunków przyrodniczych w środkowej Polsce. Interpretację przedstawiono w porządku stratygraficznym, poczynając od schyłku zlodowacenia warciańskiego, poprzez interglacjał eemski, wczesny vistulian, plenivistulian i późny vistulian, do czasów współczesnych. Wyniki, jako oparte na danych z denudacyjnych systemów zamkniętych, z natury swej nie uwzględniają udziału procesów erozyjnych, a eksponują jedynie tendencje agradacyjne lub fazy stabilizacji.
The calcareous deposits in the upper part of Quaternary-age sediments were found in the Bełchatów mine. These deposits were accumulated in closed depressions. AIl these depressions are located in Świętojanka valley and tributary valleys (Fig. 1). The geological structure, chemical and mineral composition of calcareous deposits have been discussed elsewhere (Goździk, Konecka-BetIey 1992). In the present paper, the results of pollen analysis and more detailed field investigations of relationship between the calcareous deposits and neighbouring sediments are presented. The closed depressions were developed only the where Plenivistu1ian-age thick series of fluvial silty-sandy sediments occur. Numerous syngenetic ice wedge casts were found in these sediments (French, Goździk 1988). Pollen analysis of organic layers included in the siIty-sandy sediments and fossil beetles from one such layer, indicate a tundra depositional environment. Similar sediments from such present-day environments are always icerich and susceptible to thermokarst processes. It is very possible that PlenivistuIian-age fluvial sediments from Bełchatów were the same. Later, when thermokarst processes had been developed, the closed depressions were formed in places with a higher ice concentration. There is other evidence which supports a supposition about the important rOle of thermokarst processes. The 14C dates of the beginning of the formation of the closed depressions with standing water and the period of calcareous accumulation in Świętojanka valley established by pollen analysis, are similar to analogical deposits in typical thermokarst depressions in the area of the last glaciation in northern Poland. Calcareous deposits were found always to lie on aeolian cover sands, and were never invaded by dunes. This shows that calcareous deposition began after cover formation and perhaps after dune stabilization. Organic sediments from two ancient lakes I and III (Fig. 1) were analyzed by the palynological method. Calcareous deposits and two layers of peat situated above and below them were analysed. Results of this analysis are shown on Fig. 3 for lake I and Fig. 4 for lake Ill. Radiocarbon dates of peats from the lower levels of organic material of two lakes are similar - 12 540± 120 BP, GD-1875 (lake I) and 12 710± 130 BP, GD-5031 (lake Ill). Results of pollen analysis of both peat layers indicate that during their accumulation the vegetational landscape had a character of a treeless tundra without traces of lacustrine plants. This vegetation was developed under subarctic climatic conditions.The pollen analysis shows that after the peat accumulation the development of the lakes and calcareous material deposition began. This deposition in lake I started during Older Dryas time. It lasted throughout Alleroo and Younger Dryas time and finished at the beginning of the Holocene. Pollen diagrams of calcareous sediments from lakes I and III show many similarities, but there are some differences. These differences may indicate colder conditions during the accumulation of calcareous material in lake I1I--<:haracteristicfor Boiling period. An alternative interpretation of these differences is habitat rather than climatic. In the smaller lake III accumulation finished earlier than in lake I, that is at the and of Latevistulian.
PL
W stropowej części osadów czwartorzędowych odsłoniętych w kopalni "Bełchatów" występują utwory węglanowe, które były akumulowane w zagłębieniach bezodpływowych w dolinie Świętojanki, dopływie Widawki. Zagłębienia te powstały wskutek krasu termicznego związanego z powszechną degradacją wieloletniej zmarzliny. Na podstawie badań palinologicznych utworów oraz datowania 14C możliwe było uchwycenie zarówno momentu początkowego zjawisk krasowych, jak i okresu ich intensywnego rozwoju. Występujące w spągu utworów węglanowych torfy tworzyły się w warunkach podmokłych, lecz bez stałego zbiornika wodnego, w początkowej fazie krasu termicznego. Oznaczenia wiekowe metodą HC wykazały dla torfu z zagłębienia I datę 12 540 ± 120 lat BP, a z zagłębienia III datę 12710±130 lat BP. Badania palinologiczne dowodzą, że panowały tu wówczas otwarte zbiorowiska tundry bezdrzewnej. Postępująca degradacja zmarzliny powodowała pogłębianie obniżeń, aż do utworzenia się w nich stałych zbiorników wodnych. W zbiornikach tych gromadziły się utwory węglanowe. Spektrum palinologiczne z tych utworów dowodzi, że w zbiorniku I powstały w okresie a11erOdu,natomiast nie rozstrzyga, czy utwór węglanowy w zbiorniku III tworzył się w bollingu czy allerodzie. Torfy leżące w stropie węglanów narastały już w holocenie.
Basic surface features of the Łask Interfluve near Zduńska Wola originated during the Wartanian ice-sheet areal deglaciation. The ice-sheet waning resulted in formation of groups of crevasse landforms such as kame plateaux, kame hillocks, kame terraces and melt-out depressions. The post-Wartanian morphogenesis increased diversity of the relief by rejuvenation of most of buried valleys, by cutting new valleys and raising the interfluve surface with aeolian sheets and dunes. Sand and silt were deposited in melt-out depressions. The depressions had initially functioned as closed depressions and had formed a local base level. They were incorporated into a valley network presumably at the end of the Vistulian glaciation. Blocks of dead ice melted gradually and it has led to the formation of flattenings in the melt-out depressions bottoms. The flattenings are 2-3 m high and have short gentle slopes. These slopes and the slopes of the melt-out depressions are cut with dells and basin-like valleys. Few of the cuttings continue their direction as barely perceptible, shallow flat-floored valleys drained by perennial or intermittent watercourses. In the Holocene eight types of geocomplexes with stable matter and energy structure were formed, as a result od natural processes. Man's influence has led to diversification of the environment which can be represented by 19 types of present-day geocomplexes. The 19 types are characteristic of all the melt-out depressions in the environs of Zduńska Wola, but they display a unique mosaic in each depression. It is noteworthy that the depressions function as groups of homolithic geocomplexes. Man-made changes in the depressions result from agricultural land use
PL
Artykuł przedstawia typologię i funkcjonowanie geokompleksów zagłębień wytopiskowych na tle rozwoju paleogeograficznego zachodniego fragmentu Wysoczyzny Laskiej w okolicach Zduńskiej Woli. Uwzględniono w nim naturalne procesy przyrodnicze i antropizację środowiska związaną z użytkowaniem rolniczym.
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.