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Quaternary Correlation along the Rhine

Dietrich Ellwanger1, Ulrike Wielandt-Schuster1, Manfred Frechen2, Christian Hoselmann3, Michael Weidenfeller4
1 Referat 92, RPF LGRB, Freiburg
2 LIAG Hannover
3 HLUG Wiesbaden
4 LGB-RLP, Mainz

P 1.1 in Fortschritte der Quartärstratigraphie

A lithostratigraphical correlation along the Rhine, from the Alps to the Sea, will be suggested and discussed.

 

As basics of the correlation serve the results of two projects regarding the Quaternary of southwest Germany, and the newly developed Quaternary Lithostratigraphy along the Rhine:

(1)  The “Heidelberg Basin Drilling Project“ to investigate a succession of > 500 m of Quaternary sediments in the Heidelberg basin (northern Upper Rhine Graben, URG, Gabriel et al. 2009, Weidenfeller & Kärcher 2008);

(2)  A sequence stratigraphical correlation between subglacial overdeepening unconformities of the alpine foreland (area of the Pleistocene Rhineglacier) and sediment units in the southern URG (Ellwanger et al. 2011);

(3)  The units of the new Lithostratigraphy (formations and members along the Rhine from the Bodensee area to the Middle Rhine Valley, cf. Litholex 2011 ff.).

Expansion of (2) towards a South-North-correlation, including alpine and north European glacial units, is one of the objectives of the „Heidelberg Basin Drilling Project“. We want to stress that our considerations regarding North Sea and the Bay of Biscay are solely based on published data and views (cf. Gibbard 2007, Busschers 2007, Toucanne et al. 2009).

 

Our hypothesis: All three major ice advances (glaciations) of the Rhine glacier in the Middle and Late Pleistocene (i.e. Hoßkirch, Riss, Würm) terminate with a major subglacial erosion event. There are correlative sediment input events into the southern URG representing huge impulses of sediment transport. At the other = northern end of the URG, two strong phases of erosion again indicate highly dynamic impulses, in this place as part of the Mannheim formation. How do these impulses continue further North?

The middle part of the North Sea has been blocked by ice during the Elsterian and Saalian advance, resulting in a huge lake along the present coastline, dammed by ice in the north and east and by the adjoining highlands resp. hill ridges in the south and west. Its largest tributary, next to the Elbe glacial valley, has been the Rhine. The lake eventually was due to overflow towards the Bay of Biscay, cutting the preglacial ridge of lowly hills between Calais and Dover; first time at the termination of the Elsterian, and once again in the Saalian. – Question: of what origin were the impulses that controlled the overflow? Is it solely due to the nearby British and Scandinavian ice? What about the Rhine?

We suggest the overflow was triggered by an alpine meltwater impulse of the Rhine. This impuls correlates subglacial overdeepening at the alpine margin, sediment input and erosion in the URG, the cutting of the street of Dover and the first input of alpine debris into the bay of Biscay; all as a single event.

 

Discussion: The downmelting of alpine glaciers may have started early compared with Scandinavian glaciers – and due to this phase difference of the two glacial systems the overflow may have started with the Rhenish impuls. – Regarding spatial patterns, it seems interesting though not surprising that at both ends of the system, alpine margin and North Sea, the great European watersheds are affected: at the alpine side, the Danube-Rhine divide in southwest Germany and the Rhine-Rhone divide in western Switzerland. And in the North Sea, the breakthrough between Calais and Dover interrupts the continental divide towards the Atlantic Ocean, formerly a continuous element from Northern Scotland to the Southern Vosges.

Final remarks, concerning the relevance of the correlation: If accepted, alpine and marine environment are closely linked, with strong implications towards chronostratigraphy, e.g. regarding the chronological position of the Hoßkirch/Holsteinian.

Yet, if not accepted, the normally applied multi-step model of transportation of alpine debris from the Alps to the Sea has to be used throughout. In this case, the „Fleuve Manche“ input of alpine debris into the Bay of Biscay should at least include, most probably consist of elderly Rhenish deposits (pre-Hoßkirch). Without the event-correlation, the Rhine remains a sediment transportation system, with an entirely time-marker-dependant stratigraphy.

 

Busschers, F. (2007): Unravelling the Rhine. – Diss. V.U.Amsterdam.

Ellwanger D., Wielandt-Schuster, U., Franz, M., Simon, T. (2011): The Quaternary of the southwest German Alpine Foreland. – Eiszeitalter und Gegenwart / Quaternary Science Journal, 60/2; Hannover.

Gabriel, G., Ellwanger, D., Hoselmann, C., Weidenfeller, M. (2009): The Heidelberg Basin Drilling Project. – Eiszeitalter und Gegenwart / Quaternary Science Journal, 57/3-4; Hannover.

Gibbard, P. (2007): Europe cut adrift. – Nature 448.

Litholex (2011 ff.): http://www.bgr.bund.de/litholex

Toucanne, S., Zaragosi, S., Bourillet, J.F., Gibbard, P., Eynaud, F., Giraudeau, J., Turon, J.L., Cremer, M., Cortijo, E., Martinez, P., Rossignol, L. (2009): A 1.2 Ma record of glaciation and fluvial discharge from the West European Atlantic margin. – Quaternary Science Reviews, 28.

Weidenfeller, M., Kärcher, T. (2008): Tectonic influence on fluvial preservation: aspects of the architecture of Middle and Late Pleistocene sediments in the northern Upper Rhine Graben, Germany. – Netherlands Journal of Geosciences, 87(1).

 

Letzte Änderung 19.07.2012