Search

Loess-paleosol sequences (LPSs) are essential records for reconstructing Quaternary paleoenvironments. No previous study has provided numerical chronologies of loess in Lower Franconia, southern Germany; their chronostratigraphic assumptions have relied mainly on German (pedo)stratigraphic schemes. In this study, we provide for the first time a chronology for LPSs in Lower Franconia based on optically stimulated luminescence (OSL) dating using quartz and a comparison of K-feldspar (63–100 µm) and the polymineral fraction (4–11 µm). Our results show that all obtained ages are in stratigraphic order, ranging from Holocene to late Pleistocene, and in general confirm the former stratigraphical interpretations. A good agreement of the obtained ages is observed between both feldspar grain size fractions; they also agree well with the quartz OSL ages up to ∼50 ka. However, a marked difference between the growth pattern of the dose response curves and consequently different saturation characteristics of fine and coarse grains is found. Even though in our samples the discrepancy in ages is not very significant, we suggest the use of coarse-grained K-feldspar whenever possible in order to not be confronted with unknowns such as the mineral composition of the polymineral fraction. Kurzfassung: Löss-Paläoboden-Sequenzen sind wichtige Archive zur Rekonstruktion der quartären Umwelt. Bisher hat sich noch keine Arbeit mit der numerischen Chronologie mainfränkischer Lösse befasst; die bisherigen chronostratigraphischen Einordnungen haben ihren Ursprung in deutschen (pedo)stratigraphischen Schemata. In der vorliegenden Arbeit stellen wir erstmals eine auf optisch stimulierter Lumineszenz (OSL) basierende Chronologie für Löss-Paläoboden-Sequenzen in Mainfranken vor. Hierzu wurden Quarz und in vergleichender Weise sowohl K-Feldspat (63–100 µm) als auch die polymineralische Feinkornfraktion (4–11 µm) verwendet. Unsere Ergebnisse zeigen, dass alle gewonnenen Alter in stratigraphischer Reihenfolge sind, vom Holozän bis zum Spätpleistozän, und generell die früher angenommenen stratigraphischen Interpretationen stützen. Eine gute Altersübereinstimmung liegt für die beiden Feldspatfraktionen vor; die Alter stimmen weiterhin mit den Quarz-OSL-Altern bis 50 ka überein. Im Vergleich von Feldspat-Grobkorn und Feinkorn (polymineralische Fraktion) zeigt sich bei jedoch ein stark voneinander abweichendes Verhalten in den Wachstumsverläufen der Dose Response Curves und ein sich daraus ergebendes unterschiedliches Sättigungsverhalten. Auch wenn die Unterschiede für die hier vorliegenden Proben nicht übermäßig groß sind, so empfehlen wir, wenn immer möglich, die Verwendung von grobkörnigem K-Feldspat für die Datierung, um nicht mit möglichen Unbekannten, wie der Mineralzusammensetzung von polymineralischen Extrakten konfrontiert zu sein. [ABSTRACT FROM AUTHOR]

This paper presents a new methodology for ex post assessment of direct landslide costs for transportation infrastructures. The methodology includes tools to compile, model, and extrapolate landslide losses on different spatial scales over time. A landslide susceptibility model enables regional cost extrapolation by means of a cost figure obtained from local cost compilation for a representative case study area. On a local level, cost survey is closely linked with cost modeling, a toolset for cost estimation based on landslide databases. Cost modeling uses landslide disaster management process models (LDMMs) and cost modules to simulate and monetize cost factors for certain types of landslide damage. The landslide susceptibility model provides a regional exposure index and updates the cost figure to a cost index which describes the costs per kilometer of traffic route at risk of landslides. Both indexes enable the regionalization of local landslide losses. The methodology is applied and tested in a cost assessment for highways in the Lower Saxon Uplands, NW Germany, in the period 1980 to 2010. In this 7,400-km large mountain region, 77 km of highway is located in landslide hazard area. Annual average costs of US$52,000 per km of highway at risk of landslides are identified as cost index for a local case study area. The cost extrapolation results in annual average costs for highways in the Lower Saxon Uplands of US$4.02 million. This test application as well as a validation of selected modeling tools verifies the functionality of this methodology. [ABSTRACT FROM AUTHOR]

Permanent gully channels under forest are common geomorphological features in Central European low mountain areas. In the Rehgraben/Fuchslöchergraben gully catchment in Northern Hesse, Germany the Late Pleistocene landscape formation is reconstructed based on periglacial cover beds. In addition, the Holocene landscape development and soil erosion history are investigated using anthropogenic soil sediments and alluvial fan sediments. Until now, a combination of these approaches has not been applied to a gully catchment to this extent. The distribution of the different Quaternary sediments enables the differentiation between Pleistocene and Holocene landforms. Radiocarbon and optically stimulated luminescence dating are applied to add numerical data to the relative ages of the sediments and landforms. The gully channels are oriented along Pleistocene depressions that are built up of periglacial cover beds and intercalated reworked loess. As the gully channels cut through the periglacial cover beds, especially the upper layer, the gully system is of Holocene age. At least two phases of gully erosion are identified in the alluvial fan sediments. The initial gully erosion is dated to the time span between the Late Bronze Age and Roman Times. A second gully erosion phase is dated to the 14th century and may be correlated to the severe precipitation events during this time. Gully erosion started during the Younger Holocene and is connected to human settlement and land use activity. The intense human impact hampers the application of the concept of periglacial cover beds to reconstruct landscape formation and limits it to areas where the periglacial upper layer is still preserved. [ABSTRACT FROM AUTHOR]

Landslide databases provide essential information for hazard modeling, damages on buildings and infrastructure, mitigation, and research needs. This study presents the development of a landslide database system named WISL ( W ürzburg I nformation S ystem on L andslides), currently storing detailed landslide data for northern Bavaria, Germany, in order to enable scientific queries as well as comparisons with other regional landslide inventories. WISL is based on free open source software solutions (PostgreSQL, PostGIS) assuring good correspondence of the various softwares and to enable further extensions with specific adaptions of self-developed software. Apart from that, WISL was designed to be particularly compatible for easy communication with other databases. As a central pre-requisite for standardized, homogeneous data acquisition in the field, a customized data sheet for landslide description was compiled. This sheet also serves as an input mask for all data registration procedures in WISL . A variety of “in-database” solutions for landslide analysis provides the necessary scalability for the database, enabling operations at the local server. In its current state, WISL already enables extensive analysis and queries. This paper presents an example analysis of landslides in Oxfordian Limestones in the northeastern Franconian Alb, northern Bavaria. The results reveal widely differing landslides in terms of geometry and size. Further queries related to landslide activity classifies the majority of the landslides as currently inactive, however, they clearly possess a certain potential for remobilization. Along with some active mass movements, a significant percentage of landslides potentially endangers residential areas or infrastructure. The main aspect of future enhancements of the WISL database is related to data extensions in order to increase research possibilities, as well as to transfer the system to other regions and countries. [ABSTRACT FROM AUTHOR]

• Multi-methodological approach to a unique archive for the Holocene. • Micromorphological descriptions of complex polygenic soils and sediments. • The pedosediments are characterized and compared to international taxonomies. • Changes in soil properties are driven by parent material, relief, and land use. • These are isolated and their influence is discussed in detail. Sinkholes in the karstified Middle Keuper gypsum of Middle Franconia, Germany reveal numerous archeological findings and contain unique pedosedimentary records of landscape development and human-environment interaction during the Holocene. Mudstone-derived high clay contents result in a unique set of sedimentary and pedogenic properties of these archives in that all units exhibit vertic properties. Since the horizons have a polygenic history, detailed field and micromorphological observations, together with laboratory analyses (grain-size, color, iron-pedochemistry) are the basis for a classification of the pedosediments. 14C dating provides a chronological framework for geomorphological stability phases and thus, identified soil-forming processes. The first anthropogenic colluvial sediments of the studied archive date to the Early Bronze Age and accumulated in an initial karst depression. Water saturation caused iron reduction of these early infillings. In the pedosediments above, oxidation and iron release are largely related to changes in the parent material. Here, the soil material contains coarse silt indicating an admixture of nearby periglacial slope deposits. Furthermore, fossil root traces point to a longer time with stable conditions, which we interpret as absence of humans or at least an extended period of fallow land. The superimposed sediments from the Urnfield period are more inhomogeneous and consist of material from the eroded agricultural soils of the surrounding. The characteristics of these pedosediments point to intensified human land use. Pedogenic processes such as iron release, reduction of iron, swelling-shrinking, and short-distance translocation of clay intensively overprinted all soil sediments. In this context, micromorphology proved to be an essential tool for the characterization of polygenesis in terms of soil-forming as well as redepositional processes that lead to the formation of these complex archives. The present study reflects a multi-methodological approach to a rather disregarded type of polygenic terrestrial records. It constitutes an example for the investigation of clayey pedosediments in karstic environments under moderate climate in the frame of a prehistoric geoarcheological setting. [ABSTRACT FROM AUTHOR]