River and soils cyclicities interfering with sea level changes
Paepe, R.; Van Overloop, E. (1990). River and soils cyclicities interfering with sea level changes, in: Paepe, R. et al. Greenhouse Effect, Sea Level and Drought. Proceedings of the NATO Advanced Research Workshop on Geohydrological Management of Sea Level and Mitigation of Drought, Fuerteventura, Canary Islands (Spain), March 1-7, 1989. NATO ASI Series C: Mathematical and Physical Sciences, 325: pp. 253-280. http://dx.doi.org/10.1007/978-94-009-0701-0_16
In: Paepe, R. et al. (Ed.) (1990). Greenhouse Effect, Sea Level and Drought. Proceedings of the NATO Advanced Research Workshop on Geohydrological Management of Sea Level and Mitigation of Drought, Fuerteventura, Canary Islands (Spain), March 1-7, 1989. Digitized reprint of the hardcover 1st edition 1990. NATO ASI Series C: Mathematical and Physical Sciences, 325. Kluwer Academic Publishers: Dordrecht. ISBN 978-94-009-0701-0. xix, 718 pp. http://dx.doi.org/10.1007/978-94-009-0701-0, meer
In: NATO ASI Series C: Mathematical and Physical Sciences. D. Reidel: Dordrecht; Boston; Lancaster. ISSN 0258-2023, meer
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Documenttype: Congresbijdrage
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| Auteurs | | Top |
- Paepe, R., meer
- Van Overloop, E.
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| Abstract |
Palaeosoils and river deposits alternate at specific levels within continental lithostratigraphic sequences of various parts of the globe. They attest to cyclicities through time of global importance. This study is divided into a number of chapters especially regarding the last 2,4 Ma years, the last 130K-years and the last lOK-years, which may all be read almost independently from the others. Without some lengthy chapters about the long term, middle term, and short term geosoil cycles it was quite impossible to come to any reasonable conclusion about the number of soils occurring in the Quaternary and the time stability of the geosoils in such sequences, especially of the 100K interglacial soil. Four main groups of cycles of periodicities have been detected. Two long range cycles, of 100K and 400K respectively, dominate the interglacial/glacial soil sequences of the Quaternary. These reveal the continental evidence of Imbrie’s 100K cycle and Hays’ 400K cycle. It is quite remarkable that the recorded soils in these continental systems all are relict soils of interglacial age. In the coastal fringe area these soil sequences may interfere periodically with interglacial marine deposits as well. From the North Sea and Mediterranean regions all palaeosoil development can be proved to have occurred after, or towards the end of each of the marine transgressions.Another question was whether these marine transgressions result from climatic forcing. The decreasing amplitude of the interglacial marine high level stands and glacial low stand fluctuations towards the Holocene MSL (Mean Sea Level) infer that major regression/transgression cycles are technically biased movements rather than climatically controlled ones.The next two periodicity cycles are the middle range last 100K cycle (the Upper Pleistocene or Last Glacial) and the short range 10K cycle (the Holocene). Within the last 100K a complete warm/cold cycle was achieved. During this period one interglacial (warm climatic) soil has developed at the beginning of the cycle, although after the maximum of the marine transgression. During the following cold part of the cycle at least ten other interstadial (colder climatic) soils may have developed. Fluctuations of sea level within this cycle seem mainly related to climatic changes. Finally the 10K cycle of the Holocene shows rapid fluctuations of the 40 m sea level rise during the interglacial after the maximum soil development. Before this maximum soil development some 10,000 years ago, sea level had already been rising for more than 60 m since the maximum cold of 18,000 BP.The present mean sea level (MSL) should naturally have attained its equilibrium as a result, first, of the long term tectonic rheology cycles of lithosphere, second, of the shorter climatic cycles. Geotraverses from the North Sea Basin towards the Mediterranean into the equatorial Belt proved that the tectonic cycles were of global intensity and frequency whereas the climatic cycles are increasing in both frequency and intensity towards the Equator. |
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