114-130 Eiszeitalter und Gegenwart 51 Hannover 2002 7 Abb. Loess stratigraphy in Dutch and Belgian Limburg ERIK P. M. MEIJS*) MEIJS, E. P. M. (2002): Loess stratigraphy in Dutch and fesdändischen Pollenzonen korrelieren lassen. Es las­ Belgian Limburg. - Eiszeitalter und Gegenwart, 51: 115- sen sich vier glaziale Lösszyklen und fünf interglaziale 131; Hannover 2002. Paläoböden auf der Rothem Terrasse der Maas ausma­ chen. Keywords: Loess stratigraphy, quaternary paleopedo- logy, heavy mineral analysis, Belgium, Netherlands. Introduction Abstract: Purpose of this paper is constructing a loess- Stratigraphical frameworks for loesses have had stratigraphical framework for a small region along the to be revised frequendy over the past 40 years (see Albert Canal in Dutch and Belgian Limburg. Field ob­ HAESAERTS et al. 1981 and JUVIGNE et al. 1996). servation and heavy mineral analysis are central focus Because of the similarity of the sediments, sedi- of this study. mentological and cryogenic structures and pale­ The large-scale sediment trap environment, at scarpe osols originating from the different warm and cold foots or between river-terraces led to the conservation of thick and differentiated loess sequences. The exposed stages of the Upper Pleistocene, few convincing walls of the widened Albert Canal, loess sections in the stratigraphical "marker"-horizons can be detect­ adjacent loess-exploitation zone and excavations at four ed. This is especially the case with regards to the major archeological sites did provide important data. pre-Weichselian loess-sediments, which until now, By means of characteristic lithological and paleopedo- have been difficult to subdivide stratigraphically. logical "marker" horizons, mineralogical and chrono­ In volcanic regions tephra layers can provide ex­ logical data and correlation with loess sections in Ger­ tensive lithostratigraphical markers. They often many, a reliable loess-stratigraphical framework has been constructed. Beginning with the Holsreinian, it is match­ show a distinct mineral suite and are direcdy or ing marine/ice isotope records and terrestrial lacustrine indirecdy dated by means of absolute dating meth­ pollen records. It contains four glacial loess cycles with ods. five intercalated interglacial paleosols on top of the 14 Apart from C -dating on humic sediments, char­ Rothem river terrace of the Maas. coal or molluscs, different forms of TL-dating have been developed over the past decades. How­ [Lössstratigraphie in Niederländisch und Belgisch Limburg] ever, for both of the last-mentioned dating meth­ ods many methodological problems still exist, es­ Kurzfassung: Ziel dieser Veröffentlichung ist es, für pecially in loesses, leading to different chronostrati- einen Abschnitt entlang des Albert Kanals in Nieder­ graphical interpretations. ländisch und Belgisch Limburg eine Ubersicht zur Löss­ stratigraphie zu erstellen. Since 1945 several researchers demonstrated the Die Arbeit gründet sich vor allem auf Feldaufnahmen importance of heavy mineral analysis for litho­ und Schwermineralanalysen. stratigraphical studies on loess sediments. An Talhängen und zwischen Flussterrassen kam es zur Over the past years intensified investigations have Sedimentation und Erhaltung mächtiger, reich geglie­ taken place in new and enlarged quarries in the derter Lössablagerungen. study area. The results of heavy mineral analysis, Die Wände des Albert Kanals, Lössaufschlüsse im an­ grenzenden Gebiet und vier große archäologische Aus­ in combination with lithological, paleopedologi- grabungen wurden untersucht. Auf Grund von cha­ cal and chronological data from the extreme long rakteristischen lithologischen und paläopedologischen loess sequences along the widened Albert Canal Leithorizonten, mineralogischen und chronologischen and in adjacent loess-pits, give new insight into Daten und deren Korrelation mit Lössaufschlüssen in the loess stratigraphy of the study area. Hessen wurde eine lössstratigraphische Übersicht für die Zeit seit dem Holstein-Interglazial erstellt, welche sich mit Ozean- und Eisisotopenabfolgen sowie mit Research area The research area is shown in Fig. 1. It is located *)Anschrift des Verfassers: Drs. E. P. M. MEIJS, Archeogeolab, in a part of the drainage basin of the river Maas. Veulenerbank 33, NL-6213 JR Maastricht, The Netherlands. Since the middle Pliocene (4 ma) the Maas met Loess stratigraphy in Dutch and Belgian Limburg 115 the Rhine near Aachen (Germany). Afterwards the ' (van den Berg 1996). Interglacial regimes favoured Maas moved westwards and started around 800 the formation of river floodloams and lateral ero­ ka to erode the Cretaceous and Paleocene lime­ sion. After the retreatment of the Maas from the stones and Oligocene sands in the study area (van research area, the preserved river terraces were al­ den Berg 1996). The continuous uplift of the area, ternately eroded by wind- and water-action and the alternation of glacial and interglacial periods covered by eolian sands and loesses. The bounda­ and the lateral westward shifting of the Maas were ry between the coversand area in the north and responsible for the preservation of an extraordi­ the loess belt in the south is located near Gellik nary extended and complete river terrace sequence. (Fig. 1). The present landscape is smoothly undu­ Transition periods between interglacial and glacial lating, with SW-NE orientated valleys, draining to times were favourable for river-erosion and inci­ the rivers Jeker and Maas in the east. sion, while gravel-accumulation took place under Several brickyards are exploiting loess-pits near cold and severe conditions, on the base of widely Kesselt and Veldwezelt (Nelissen pit "Kesselt" and observed cryogenic features within the gravel beds Vandersanden pits "Veldwezelt-Hezerwater" and ^Eindhoven A ^--v 777e NETHERLARY.S/ Dusseft torf N GERMANY BELGIUM 1 1 W[ Maastricht Cologne? • (iv.v.v.v.v.v.v; ® Aachen 30 km Fig. 1: Location of the study area and position of the cross sections L-M, A-K, a-b, d-c, f-e, g-h and i-j, which are shown in Fig. 2, 4, 5 and 6. At the right bottom: two fossil meander channel-beds from Rothem-1 and Rothem-2 river-terraces are indicated on the base of outcrop and drilling information. Abb. 1: Lage des Forschungsgebietes und Lokalisierung der Aufschlüsse L-M, A-K, a-b, d-c, f-e, g-h und i-j in Fig. 2, 4, 5 und 6. In der rechten unteren Ecke sind, basierend auf Bohrungen und Aufschlüssen, zwei fossile Mäanderbögen der Rothem-1 und Rothem-2 Flussterrasse wiedergegeben. 116 ERIK P. M. MEIJS "Op de Sclians"). In fact the area along the Albert of a terrace-division in the Gravenvoeren sequence Canal is an important loess-exploitation zone throughout the Maas terrace area between Liege which will be further investigated in the future. in Belgium and Roermond in The Netherlands The Nelissen pit "Kesselt" was, until 1996, the (Felder & Bosch 1989 and van den Berg 1996). type-location for the so-called Hesbaye loess, According to Felder & Bosch (1989) the Pieters- which induced research by several universities. In berg and Maarland terrace levels are present over the future this site will possibly be assigned as the a distance of 100 meters, in a SW direction from type-location for the rare Upper Saalian "B-loess" point A and in a NE direction from point K seen (see chapter chronostratigraphy). The Vandersand- in the cross-section Lafelt-Oud Caberg, with gravel en company started exploiting the loess-pit "Op bases at about 98 m ASL and 38 m ASL (Fig. 1, de Schans" in March 2000 (Fig. 1). For the study Fig. 2). of pre-Weichselian loesses, it is a promising loca­ It is clear that during long periods a sediment-trap tion because it is situated in line with the most existed between the heights of the Pietersberg and complete and differentiated pre-Weichselian out­ Gravenvoeren terraces, which resulted in an ex­ crop along the widened Albert Canal (Fig. 2). tremely thick loess cover in between. Between 1975 and 1985 the Albert Canal was wid­ ened and detailed research of the exposed walls Heavy mineral analysis led to a thorough understanding of the geological As stated above, lithological, sedimentological and and geomorphological genesis of this area. Ex­ paleopedological analyses of loesses are rarely able posed sediments in neighbouring loess-pits were to discriminate between the different warm and then correlated to the Albert Canal sequences. cold stages of the Upper Pleistocene. However, The discovery of four major archeological sites correlations between different loess sections can (Maastricht-Belvedere, Kanne, Kesselt and Veld- be strengthened and stratigraphical conclusions wezelt-Hezerwater) in the research area led to ad­ can be drawn by means of heavy mineral analysis. ditional stratigraphical and chronological research. In combination with micromorphological and In conclusion, the research area could be consid­ lithological research, the content of the green ered as a key-region for present and future loess- amphibole and volcanic minerals are used to cor­ stratigraphical research. relate individual loess sections and to construct a loess-stratigraphical framework for the research Terrace sequence of the river Maas area. In Fig. 2 the roughly SW-NE and S-N orientated Methods cross-sections clearly show the strong influence Loess minerals: of river erosion and aggradation processes in the The investigation of the mineralogical composi­ area. The cross-section Lafelt-Oud Caberg (A-K; tion of the loess fraction (30-63 gm) in relation to Fig. 2 bottom) is constructed on recorded sections the loess stratigraphy began in The Netherlands along the Albert Canal and adjacent loess-pits and (van Doormael 1945). This research was continu­ additional drilling information (Halet 1932, ed by Gullentops (1954), Lautridou (1968), Ju- Felder & Bosch 1989 and Geolab 1996), while vtgne (1978,1985), Balescu & Haesaerts (1984), the Vroenhoven-Veldwezelt cross-section (L-M; Meijs (1985), Janus (1988) and Henze (1998) in Fig. 2 top) is based on outcrop-information along the loess-belt of France, Belgium, The Nether­ the widened wall of the eastern side of the Albert lands and Germany. Juvigne (1978) proposed the Canal.