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Robust chronologies of Late Pleistocene and Holocene volcanic eruptions are vital for hazard analysis but accurate and precise dating of these events is often difficult. Here we apply various luminescence techniques to quartz and polymineral extracts from heated crustal xenoliths enclosed in scoria and volcanically heated bedrock in the Quaternary Eifel Volcanic Field (EVF), Germany. Consistent results from red thermoluminescence (RTL) and optically stimulated luminescence (OSL) of quartz and from post-infrared infrared stimulated luminescence of polymineral material demonstrate complete luminescence signal resetting during lava emplacement and sufficient signal stability. RTL and OSL age underestimation of one sample with independently known age from the lava contact zone could be eliminated by annealing before laboratory regenerative irradiation. The average luminescence age of 33.6 ± 2.4 ka for the Wartgesberg eruption is in good agreement with independent age control, while the average age of 15.5 ± 1.1 ka for the Facher Hohe scoria cone is much younger than previously assumed. This result represents the third youngest known eruption in the EVF. Our new data are in line with the hypothesized climate-controlled triggering of Eifel volcanism and confirm that active volcanism related to asthenosphere upwelling migrates from NW to SE in the EVF.

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1) As we are working in the same and similar settings on the eastern Canary Islands and also endeavouring to establish reliable ages based on luminescence dating, we followed the numerical ages published in this paper with great interest. Since besides a wellestablished stratigraphy it is always preferable to have a robust time control, we should be happy to accept these new ages from the Rosa Negra quarry at this time (Fig. 4). However, it is essential to have some detailed explanations (methods) on the dating procedure applied by the authors. In particular, we would like to know on what material luminescence dating was conducted: Was it IRSL on feldspar, or was it OSL on quartz? Were fine or coarse grains used? Were single or multiple aliquot protocols applied? How were dose

Vulkanische Ereignisse des mittleren und oberen Quartär sind schwer zu datieren, insbesondere, wenn geeignete Minerale für eine 40Ar/39Ar-Datierung fehlen. Mit diesem Artikel werden erste Tests einer neuen Anwendungsmöglichkeit der TL-Datierung an Maar-Tephra und Xenolithen präsentiert, um derartige Eruptionsvorgänge zu datieren. Hierbei wird berücksichtigt, dass ein Rückstellen des latenten geologischen TL-Signals der Gesteinsfragmente während des Eruptionsvorganges eventuell nur unvollständig erfolgte. Aus diesem Grund wurde die „Partial heat- longest plateau-Technik (PHLP) entwickelt, um genau diesem Problem Rechnung zu tragen. Die neu entwickelte Technik kann helfen, eine Überschätzung von TL-Datierungen infolge der unvollständigen Rücksetzung des TL-Signals zu vermeiden. Dies wird für vulkanische Ablagerungen im Eifel-Vulkanfeld demonstriert, die eine Zeitspanne von 11 bis 300 ka umfassen. Obwohl das Problem starken anomalen Ausheilens des TL Signals vulkanischer Feldspäte und anderer vulkanischer Minerale umgangen wurde, existiert immer noch das Problem einer Unterschätzung geologischer Alter als Folge eines langfristigen anomalen Ausheilens im TL Signal. Die orange-roten TL-Emissionen (RTL) reiner feinkörniger Quarzproben aus Xenolithen wurden an zwei Proben getestet. Dieser Datierungsansatz verlangt jedoch noch weitere systematische Untersuchungen., research

The loess/paleosol sections of Batajnica/Stari Slankamen (Serbia), Mircea Voda (Romania) and Stary Kaydaky (Ukraine) were geochemically characterized based on discriminant analysis of major and trace elements, the ratios of Al/Ti, Fe/Ti and Al/Fe, the A-CN-K ternary plot and element enrichment/depletion relative to the average composition of the upper continental crust. The origin of the loess material in the southern Pannonian Basin (Vojvodina), the lower Danube Basin/Dobrudja and the Dnieper area was evaluated by comparison with the representative element composition of possible source areas and by considering the geomorphodynamic setting. Also the background values of the initial magnetic susceptibility of the loesses were taken into account. For the lower Danube Basin, Dobrudja and the Ukraine, paleowind direction was reconstructed based on the geographic distribution of sandy soil texture and dunes related to river systems. Finally, loesses were evaluated as possible samples of the average upper continental crust. Our results show that Danube and Dnieper loess areas can be clearly distinguished. The former reveal higher Al and Fe contents, the latter higher Si, Zr, Hf content and indications of effective mineral and grain size sorting. We can confirm that Vojvodina loess originated from Danube alluvial material and loess of the Dnieper area from glaciofluvial sediments of the Fennoscandinavian ice sheet. The Dobrudja loess derived also predominantly from Danube alluvium, but shows significant contribution of a second loess source, probably the glaciofluvial sediments of the Ukraine. This was forced by northerly katabatic winds from the Fennoscandinavian ice sheet, whereas WNW winds prevailed in the Western Walachian plain. The studied loesses reflect the average composition of the upper continental crust. Yet, biases exist due to selective mineral/element enrichment and depletion in the course of previous sedimentary recycling phases, respectively. Material of all studied loess deposits seems to derive originally from sedimentary rocks.

There are several competing hypotheses for theorigin of loess in Europe but quantitative evidence is stillrare. Here, Sr-Nd isotopic and bulk elemental compositionof loess from Marine Isotope Stages 2 and 3 fromthree study regions in Central Europe – Nussloch (Germany),Grub (Austria) and Tokaj (Hungary) - are analyzed.This study aims at examining differences and similaritiesof loess deposits throughout Europe, correlating loesswith potential source rocks from major mountain rangesand comparing loess with floodplain sediments from mainrivers as integrated samples of the drainage areas. The resultsshow that European loess deposits are largely uniformand that sediment sources have been rather stablein the Southern and Eastern parts of Central Europeand more variable in West Central Europe. However, themethods used are not sufficient to unequivocally confirmand reject potential sediment sources but, in combination,help to identify the most likely sediment origins. While adirect correlation of loess and potential source rocks is dif-ficult, the comparison with floodplain sediments is mostpromising and confirms previous hypotheses. Loess fromTokaj and Grub is most likely a mix of material transportedby the Danube River and sediments from the surroundingmountains. Rhine River sediments are probably the mainsource of loess at Nussloch.

Similar to the Chinese loess, the loess deposits surrounding the high mountain regions of Central Asia play an important role in understanding the climate and environmental change during the Pleistocene in Eurasia. Despite their thickness and widespread distribution, the loess deposits in southeast Kazakhstan have so far not been investigated in detail. The Remisowka loess–palaeosol sequence is located in the vicinity of the North Tien Shan Mountains at an altitude of 1070 m above sea level. In the profile under study nine loess layers were distinguished, intercalated by eight pedocomplexes and so indicating a similar cyclicity like the loess–palaeosol sequences in Central Asia and China. At the Remisowka section, 12 loess samples were taken to set up a more reliable chronological model for the section, using a luminescence dating approach. Polymineral fine grains were investigated by infrared optically stimulated luminescence applying the multiple aliquot additive dose protocol. Preliminary fading experiments were carried out for one sample taken from the uppermost loess layer. While the results of the uppermost layer are in agreement with geological age estimates and indicate a correlation to the Late Glacial, age underestimation is very likely for the samples below the first weak palaeosol. No significant age increase with depth was recognised. The reason for this age underestimation is not yet fully understood but could be related to anomalous fading. Further methodological approaches are necessary as well as a combination of different chronometric techniques for improvement of the results.

Loess research in Germany has a long tradition dating back to the early works of von Leonhard [von Leonhard, K.C., 1823/1824. Charakteristik der Felsarten. 3 Bde., 772 S. Heidelberg (J. Engelmann).] and his contemporary geoscientists. Ever since that time, German researchers and loess research within Germany have provided important contributions to the international ‘state of the art’. To date, however, perceptual “unconformities” have existed in both the continuity of loess research in Germany and the interpretation of the loess record in both the palaeoecological and the stratigraphic sense. This paper briefly highlights some relevant periods of loess research in Germany and the approaches adopted, from the early days to the present. The development of a refined stratigraphy of the last glacial loess in Germany during the second half of the 20th century is reviewed in the contribution by A. Semmel. Fundamental contributions were first published by Schonhals, Freising and Brunnacker. In the course of the subsequent work of the Loess Commission of the International Union for Quaternary Research (INQUA), the stratigraphy of the Wurmian loess has since been refined in almost all loess regions of Germany, and schemes consistent in their fundamental features have been published. In recent years, contributions have focussed on age determination, in particular those based on luminescence dating techniques.

Twelve samples extracted from silt-rich sediments in intramontane basins (“duns”) in the Siwalik system in SW Nepal were dated by thermoluminescence. The samples from the sections at Arjun and Gidhniya, which underwent intensive postdepositional rubefication, yield ages between ca. 30 and 10 ka, whereas more yellowish clayey silt on top of red soil sediments at Babai Khola was deposited as recently as 4 ka. The ages presented here are relevant to the dating of the Palaeolithic in the area and suggest a late Glacial age of the “Hoabinhian” at Arjun.

New field investigations of the Achenheim sequence (Alsace, France) allow for the characterization of variations in the low-field magnetic susceptibility over most of the last climatic cycle, i.e., the past 130,000 yr. New stratigraphic data and thermoluminescence measurements permit reassessment of the previous chronological interpretation of the Upper Pleistocene at Achenheim. A high-resolution analysis of magnetic susceptibility discloses the occurrence of a fine-grained “marker” horizon which was also found recently in another section. This horizon is interpreted as a small-scale dust layer deposited prior to the main interval of loess deposition. The horizon, deposited at the marine isotope stage (MIS) 5/4 boundary, has been found in other loess sequences and is especially prevalent in central Europe. It is characterized by low susceptibility values and a grayish color. New thermoluminescence dates indicate that the loess deposition took place after the MIS 5/4 boundary, i.e., after 70,000 yr. These results are consistent with the Greenland GRIP ice-core dust record which also demonstrates a dusty atmosphere after 72,000 yr ago. On a more regional scale, the Achenheim loess sequence demonstrates a reliable correlation between the western side of the Eurasian loess belt and the dust record of the Greenland ice cores.

In the north of the island of Lanzarote (Canary Islands, Spain), two palaeosols from different sites were baked by overlying lava flows. Using red thermoluminescence (RTL) dating, late Middle Pleistocene ages were obtained, both varying around 170 ka thus indicating the simultaneity of the volcanic events. Blue thermoluminescence dating using different measuring techniques of the same sample material from one site (the Mala dune) yields somewhat lower ages, varying around 125 ka. However, this result is not in contradiction with the RTL age since anomalous fading was detected, expected to cause a significant underestimation of blue thermoluminescence results. Electron spin resonance dating from land snails overlying the lava flow yielded ages between 204 and 123 ka. Although this dispersion is rather large for material originating from the same stratigraphic horizon, it has to be taken into account that the amount of sample material and thus signal intensity was very low. Furthermore, small measured sample quantities are very vulnerable to dosimetric inhomogenities in the surrounding material, being a further source of uncertainty. Thus, these ESR ages bracketing the RTL age are a further support for a late Middle Pleistocene age of the lava flow. The Middle Pleistocene RTL ages of about 170 ka fill a conspicuous gap in the volcanic chronostratigraphy of Lanzarote, demonstrating that post-erosional volcanism on Lanzarote was obviously more continuous during the Middle and Late Quaternary than known before. Thus, these results demonstrate the potential of RTL and ESR dating to improve the timing of the Quaternary volcanism of the Canary Islands.

Several profiles of Late Glacial-Holocene dune sands in the glacial outwash plains of Brandenburg were sampled to systematically investigate and compare thermoluminescence ages from the 90–200 μm quartz and K-feldspar fractions. An ultraviolet peak in the emission spectrum of the Honle SOL2 sunlamp, which is not normally abundant in natural sunlight after passing through the atmosphere, is thought to be responsible for a stronger phototransfer of charges in quartz compared with daylight bleaching. To eliminate these errosrs as far as possible, a two day bleaching under natural sunlight is suggested.

As part of a chronological study of the famous Upper Pleistocene Nussloch (Germany) loess sequence, three samples were collected to check the applicability of palaeodosimetric dating methods (OSL and ESR) to quartz grains. The ESR-multicentre method showed a partial bleaching of the ESR centers in aeolian sands. This partial bleaching was also observed by OSL. Laminated loess seemed to be sufficiently bleached but showed a large scatter of the doses, which we ascribed to heterogeneous responses of the luminescent grains to the SAR protocol. Ages could nevertheless be calculated for the three samples and were found to be somewhat older than the IRSL and 14 C ages obtained for the same layers of the laminated loess.

Late Pleistocene loess-palaeosol sequences are widespread in the Vojvodina region, with thicknesses reaching a maximum of about 20m. Our investigations include more than 40 of these loess sections. Geochronology of the last glacial loess-palaeosol sequences, based on luminescence dating and amino acid racemisation, provides correlations between Upper Pleistocene loess-palaeosol sediments in Vojvodina and comparable deposits at other European localities. Sedimentary logs of magnetic susceptibility, grain-size measurements and carbonate content, combined with malacological evidence, indicate two main relatively cold and arid phases during the last glacial period, related to intensive accumulation of loess units L1 L1 and L1 L2, as well as many brief episodes of dry and windy climatic conditions, suggesting a possible relationship with cold events recorded in the North Atlantic region. Generally, late Pleistocene climate in the region was dry and relatively warm, compared with glacial period sites in central Europe, and was characterised by sharp differences between glacial and interglacial modes. New data and interpretations presented in this study emphasise the significance of loess-palaeosol sequences in Vojvodina for the reconstruction of the temporal and spatial evolution of late Pleistocene palaeoclimate in this part of Europe. Copyright © 2007 John Wiley & Sons, Ltd.

The layered silts of Wadi Feiran and its tributaries (Central Sinai, Egypt) form profiles up to 50 m in height. They have been the subject of numerous geoscientific studies, but their formation and origin is still under discussion (i.e. lacustrine? fluvial? glaciation? true loess? river terraces?). The investigations of the authors confirm the silts to be alluvial loess. Due to Miocene foraminifera embedded in some of the silts around the oasis of Feiran, the origin of the aeolian material can be traced back to the Gulf of Suez. After sedimenting on the slopes of the wadis (Feiran, Es Sheikh, Solaf) the silts were later washed out by the rain, transported by a meandering river and sedimented as “overbank fines” and “crevasse splays” next to coarser material. At some locations the sedimentation took place in a swamp-like environment. Thermoluminescence dating revealed the time of sedimentation (as overbank fines etc.) being between 27 and 12 ka old. Based on geological and geochemical data the palaeoclimatologic development of the region is discussed.

Thermoluminescence (TL) dating of Quaternary sediments has developed rapidly in the last few years. As paleosols often prove to be useful stratigraphic marker horizons, it is of great interest to obtain absolute ages for them. A technique is proposed which increases the range of TL dating of loess to some 300 ka. Special problems associated with paleosol TL dating, such as sampling and dose rate evaluation, are discussed. Three examples for paleosols from West German loess regions are presented: the intra-Wurmian ‘Lohner Boden’ soil (28–30 ka), Lower Wurmian chernozem-like soils (ca. 70 ka), and the penultimate interglacial soil (‘Karlich Interglacial’, between 230 and 170 ka).

Summary The character and the distribution of slope debris and “plateau loams (Plateaulehme)” in the “Hochwald” region, Western Hunsruck, are described. According to the heavy mineral association of the youngest “Laacher Bimstuff” (pumice-tuff), the slope debris may be divided into basal (pre-Allerod age) and covering layers (post-Allerod age, that is Dryas III). Some of the “plateau loams” may possibly be of Tertiary age but others which were formerly dated as older Pleistocene or Tertiary, are thought to have a younger origin. As far as the development of small valleys is concerned, a period of strong linear incision during the older Wurm era was followed by a distinct period of infilling by coarse sediments. Following the Allerod age, processes of accumulation are again characteristic for the development of the valleys. At present, only small amounts of humic soil are being washed from cultivated land. Vertical incision by streams occurs exceptionally. Generally, the accumulation of flood sediments seems to be predominant.

Since the Oligocene, the Hunsriick was uplifted about 200–250 m, in relation to the Rheinhessen Plateau (Mayence Basin), and tilted southwards with amounts of up to 50 m. The plateau uplift includes parts of the Saar-Nahe Basin. The quaternary partial uplift does not exceed 40–50 m.

The cause of the rapid transition from lush grasslands and woodlands of the Early Glacial interstadiul to Pleniglacial barrens in Europe is still a mystery. In the loess sections of Bohemia and Austria this transition is associated with thin layers of fine-grained airborne dust known as ‘markers’, believed to be deposited by major contineiital-scale dust storms. Here we present evidence that a similar. sharply delimited layer with a minimum TL age of 64.9 ± 6.9 ka separates the autochthonous humus steppe soils from abiogenic sediments of the Achenheim 1 pedocomplex in France. The soil complex has been previously correlated on pedostratigraphic grounds with marine oxygen isotope stage (MIS) 5. Given its age and stratigraphic position, the dust layer correlates with the PKII marker in Bohemia. The rccogiiition of a marker in Achenheim suggests that the development of the Early Glacial steppe soils ended abruptly not only in central Europe, but also in Alsace, France, prior to 65 ka, possibly as a result of a single continental-scale dust storm.