The Pliocene Lillo, Poederlee, Merksplas, Mol and Kieseloolite Formations in northern Belgium : a synthesis

The Pliocene of Belgium subcr ops in the northern part of the country and for more than a century has been the subject of many palaeontological and stratigraphical studies thanks to numerous temporary excavations that became accessible during the civil works for the expansion of the Antwerp Harbour. It was only during subsurface mapping from the 1980s onwards, in combination with cored and geophysical logged drillings, that these data became integrated which has led to new stratigraphical insights. The data relating to the current stratigraphy have now been inventoried, assessed, synthesized and a refined stratigraphical framework and correlation scheme is presented

Special External Effects on Fluvial System Evolution

Rivers are an excellent witness of the dynamics affecting Earth’s surface due to their sedimentary products and morphological expression, which may be considered as fluvial archives. Until now, the focus has been on evaluating the general impact of individual external factors. However, the importance of the specific environmental characteristics of these factors has become increasingly recognized, as highlighted in recent case studies. For example, the effects of regional climate, differentiated topography and vegetation, and frozen ground appear to play an essential role in the evolution of the fluvial system. Integration of such environmental conditions in the processes that were active within the complex fluvial system will open new perspectives in our progressive understanding of the evolution of landscape form, ecology, sediment fluxes, and hydrology of the system within the framework of the external drivers such as tectonics, general climate, and human activity. This is an appealing challenge that we wish to address in the present Special Issue under the aegis of the Fluvial Archives Group (FLAG)

Late Pleistocene Stratigraphy and Fluvial History of the Dinkel Basin (Twente, Eastern Netherlands)

Das glaziale Dinkelbecken ist erfüllt mit einer Sequenz von fluviatilen und äolischen Ablagerungen. Die Spätpleistozän-Stratigraphie und Paläomorphologie würde mit Hilfe von neuen Aufschlüssen, Bohrungen und geo-elektrischen Sondierungen erforscht. Besondere Beachtung galt der Verfeinerung in der Lithostratigraphie des Dinkeltals, des Typusgebietes der Twente-Formation, und einer Rekonstruktion des Ablagerungsmilieus in den verschiedenen Perioden der Weichseleiszeit. Die Talauffüllung besteht aus Sanden mit Lehm-, Ton- und Torfschichten. Drei wichtige Leithorizonte wurden innerhalb der Twente-Formation gefunden. Diese drei Horizonte sind von erosiven Bildungen begleitet. Einige charakteristische Einheiten sind unterschieden, jede Einheit entspricht spezifischen fluviatilen und äolischen Verhältnissen. Während der Eemzeit und der Früh-Weichseleiszeit gab es Flüsse mit hoher Sinuosität in einem sumpfigen alluvialen Tiefland, mit lokal lakustrischen Verhältnissen. Das Untere Pleniglazial ist charakterisiert durch einen tiefen fluviatilen Einschnitt. Darauf folgt fluviatile Zuschüttung während des Mittleren Pleniglazials, hauptsächlich durch mäandrierende Flüsse. Während des Oberen Pleniglazials lösten sich die Flüsse in sich überkreuzende Flußarme auf. Äolische Ablagerung nahm allmählich zu. Die Entwicklung der Beuningen-Steinsohle und die Ablagerung von Flugdecksanden zeigen zunächst die Dominanz von äolischen Prozessen im Tal. Erneute fluviatile Aktivität fing mit Einschneidung im Spätglazial an, gefolgt von der Ablagerung von Sedimenten mäandrierender Flüsse.researc

A review of the lower and middle Miocene of northern Belgium

The stratigraphy, sedimentology and paleogeography of the lower and middle Miocene Berchem and Bolderberg Formations from northern Belgium have been extensively studied during the last decades, a.o. in the framework of doctoral research, as parts of subsurface mapping and interregional geological correlation initiatives by governmental organizations. The last formal stratigraphical revision on formation level, however, almost dates from two decades ago, notwithstanding the fact that a wealth of new data has become available. A compilation and assessment of the stratigraphical data of the lower and middle Miocene has been carried out and a refined stratigraphical framework-based on dinoflagellate cyst stratigraphy-is presented. Recommendations for the National Commission for Stratigraphy of Belgium are proposed. A new member, the Molenbeersel member, is proposed for the glauconite-bearing silts and fine sands in the upper part of the Bolderberg Fonnation in the Roer Valley Graben.Rhine during the late Tortonian

Late Quaternary paleoclimatic and geomorphological evolution at the interface between the Menyuan basin and the Qilian Mountains, northeastern Tibetan Plateau

The Tibetan Plateau is regarded as an amplifier and driver of environmental change in adjacent regions because of its extent and high altitude. However, reliable age control for paleoenvironmental information on the plateau is limited. OSL appears to be a valid method to constrain the age of deposits of glacial and fluvial origin, soils and periglacial structures in the Menyuan basin on the northeastern Tibetan Plateau. Dating results show glaciers advanced extensively to the foot of the Qilian mountains at ~. 21. ka, in agreement with the timing of the global Last Glacial Maximum (LGM) recorded in Northern Hemisphere ice cores. Comparison with results from the eastern Tibetan Plateau suggests that the factor controlling glacial advance in both regions was decreased temperature, not monsoon-related precipitation increase. The areas of the Menyuan basin occupied by glacio-fluvial deposits experienced continuous permafrost during the LGM, indicated by large cryoturbation features, interpreted to indicate that the mean annual temperature was ≥. 7. °C lower than at present. Glacio-fluvial systems in the Menyuan basin aggraded and terraces formed during cold periods (penultimate glaciation, LGM, and possibly the Younger Dryas) as a response to increased glacial sediment production and meltwater runoff then. © 2013 University of Washington

Late Quaternary aggradation and incision in the headwaters of the Yangtze River, eastern Tibetan Plateau, China

River aggradation or incision at different spatial-temporal scales are governed by tectonics, climate change, and surface processes which all adjust the ratio of sediment load to transport capacity of a channel. But how the river responds to differential tectonic and extreme climate events in a catchment is still poorly understood. Here, we address this issue by reconstructing the distribution, ages, and sedimentary process of fluvial terraces in a tectonically active area and monsoonal environment in the headwaters of the Yangtze River in the eastern Tibetan Plateau, China. Field observations, topographic analyses, and optically stimulated luminescence dating reveal a remarkable fluvial aggradation, followed by terrace formations at elevations of 55-62 m (T7), 42-46 m (T6), 38 m (T5), 22-36 m (T4), 18 m (T3), 12-16 m (T2), and 2-6 m (T1) above the present floodplain. Gravelly fluvial accumulation more than 62 m thick has been dated prior to 24-19 ka. It is regarded as a response to cold climate during the last glacial maximum. Subsequently, the strong monsoon precipitation contributed to cycles of rapid incision and lateral erosion, expressed as cut-in-fill terraces. The correlation of terraces suggests that specific tectonic activity controls the spatial scale and geomorphic characteristics of the terraces, while climate fluctuations determine the valley filling, river incision and terrace formation. Debris and colluvial sediments are frequently interbedded in fluvial sediment sequences, illustrating the episodic, short-timescale blocking of the channel ca. 20 ka. This indicates the potential impact of extreme events on geomorphic evolution in rugged terrain