Abstract In recent years, watershed modelers have put increasing emphasis on capturing the interaction of landscape hydrologic processes instead of focusing on streamflow at the watershed outlet alone. Understanding the hydrologic connectivity between landscape elements is important to explain the hydrologic response of a watershed to rainfall events. The Soil and Water Assessment Tool+ (SWAT+) is a new version of SWAT with improved runoff routing capabilities. Subbasins may be divided into landscape units (LSUs), e.g., upland areas and floodplains, and flow can be routed between these LSUs. We ran three scenarios representing different extents of connectivity between uplands, floodplains, and streams. In the first and second scenarios, the ratio of channelized flow from the upland to the stream and sheet flow from the upland to the floodplain was 70/30 and 30/70, respectively, for all upland/floodplain pairs. In the third scenario, the ratio was calculated for each upland/floodplain pair based on the upland/floodplain area ratio. Results indicate differences in streamflow were small, but the relative importance of flow components and upland areas and floodplains as sources of surface runoff changed. Also, the soil moisture in the floodplains was impacted. The third scenario was found to provide more realistic results than the other two. A realistic representation of connectivity in watershed models has important implications for the identification of pollution sources and sinks.
The Crummock Water aureole, an ENE-trending elongate zone of bleached and recrystallized Skiddaw Group rocks, 24 km in length and up to 3 km wide, is a zone in which pervasive metasomatism has modified the composition of the dominantly siltstone and mudstone lithologies. The bleached rocks show a substantial net gain of As, B, K and Rb and loss of Cl, Ni, S, Zn, H 2 O and C. Carbon loss is responsible for the bleaching. There are smaller and more localized net losses of Cu, Fe, Li and Mn, and gains of Ca, F and Si, whilst Co, Pb and REE are at least locally redistributed. Many chalcophile elements show evidence of initial widespread depletion and subsequent local enrichment. The mineralogy of the rocks is little affected by the geochemical changes. Like their counterparts outside of the bleached zone, the metasomatized rocks consist essentially of quartz, chlorite, muscovite, paragonite and rutile. Small aggregates and porphyroblasts of white mica and chlorite are developed. The metasomatism, which was accompanied by tourmaline veining, is superimposed on a contact metamorphic event. It post-dates the main Caledonian cleavage but pre-dates late Caledonian minor folds. Rb-Sr whole rock isochrons suggest that the metasomatic event occurred at c. 400 Ma and was thus associated with the Lower Devonian Shap-Skiddaw granite magmatism and not the earlier Eskdale Granite or Ennerdale Granophyre magmatic events. Modelling of Bouguer anomalies indicates that geological and geochemical constraints are most simply satisfied if the metasomatism is attributed to a buried, elongate, highly evolved granitic body intruded along the northern margin of a major granitic-granodioritic component of the Lake District batholith. The bleached zone is associated with a major lineament, which may reflect basement control on the location and form of the buried intrusion. Loss of metals from the bleached rocks is related to penecontemporaneous and subsequent hydrothermal vein mineralization and demonstrates that Skiddaw Group sedimentary rocks were a source of ore metals in the Lake District.
SUMMARY The system of stratigraphic classification used by field geologists working in Africa is briefly reviewed and a hierarchy of terms is suggested, taking into account the requirements of those interested in local field problems and those concerned with the tectonics and composition of the African continent as a whole. On the local scale, rock units are best named according to the lithostratigraphic classification. On a regional scale, the criteria for defining rock units are essentially tectonostratigraphic and two new terms for them, in ascending order of magnitude, Orogenic Assemblage and Orogenic Complex , are proposed. The two schemes are united through the Sequence , which can contain any number of lithostratigraphic units of any order of magnitude.
We documented that the Wartanian (younger Saalian) Lower Rogowiec Till exposed at Belchatow, central Poland, is not sedimentologically or structurally homogeneous, and suggested that the till macrofabric patterns and deformation structures may be related to stress conditions in the glacier at the time of deposition. The distribution of deformation structures below and within the till forms a pattern, most probably associated with compressive flow and/or with stronger stress reaction, creating stronger fabrics, above clay beds due to high pore water pressure. The intervening areas, lacking deformation structures, occur between the zones of compression, where pressure would have been less. These patterns occur in a repeated sequence along the sections, which suggests that there may be a control, such as basal glacier stress conditions. The sites showing deformation occur about every 10–20 m. This could imply that the zones of shearing at the ice front have a similar spacing. There are no features in the pattern of the till macrofabrics and deformation structures to suggest that the local Kleszczow Graben or a pre-existing valley had any effect on the mode of till deposition.
Abstract The Latterbarrow Formation, 400 m thick, has been mapped and subdivided informally into three members. These consist of quartz wacke sandstone and, in the upper member only, intercalated mudstones. The formation unconformably overlies the fossiliferous Skiddaw Group of late Tremadoc to middle Arenig age and is overlain disconformably by volcanic rocks that have been attributed to the Borrowdale Volcanic Group. Chemically, the sandstones are characterized by very low concentrations of CaO, Na 2 O, and K 2 O and unusually high total iron. MnO and MgO, such that iron, as Fe 2 O 3 , exceeds Al 2 O 3 . Mudstone in the upper member is illite rich, has a high K 2 O content and is compositionally similar to K‐bentonites derived from volcanic ash. Sedimentary structures and petrography suggest that the sediments were deposited in a sandy estuary and were derived from a similar source area to that of the Skiddaw Group. Throughout the succession there is evidence of distal volcanism, probably representing the earliest eruptions of the Borrowdale volcanic episode. The Redmain Formation, 100 m thick, is unconformably overlain by Carboniferous rocks but its relationship to the underlying Skiddaw Group is unknown. Though this lithic arenite shows some petrographic and geochemical similarities with the Latterbarrow sandstone, differences are such that it is possible they are not equivalent in age. The Redmain sandstone may be derived from the erosion of Skiddaw Group rocks.
Abstract Detailed study of subsurface deposits in the Polish Sudeten Foreland, particularly with reference to provenance data, has revealed that an extensive preglacial drainage system developed there in the Pliocene–Early Pleistocene, with both similarities and differences in comparison with the present-day Odra (Oder) system. This foreland is at the northern edge of an intensely deformed upland, metamorphosed during the Variscan orogeny, with faulted horsts and grabens reactivated in the Late Cenozoic. The main arm of preglacial drainage of this area, at least until the early Middle Pleistocene, was the Palaeo–Nysa Kłodzka, precursor of the Odra left-bank tributary of that name. Significant preglacial evolution of this drainage system can be demonstrated, including incision into the landscape, prior to its disruption by glaciation in the Elsterian (Sanian) and again in the early Saalian (Odranian), which resulted in burial of the preglacial fluvial archives by glacial and fluvioglacial deposits. No later ice sheets reached the area, in which the modern drainage pattern became established, the rivers incising afresh into the landscape and forming post-Saalian terrace systems. Issues of compatibility of this record with the progressive uplift implicit in the formation of conventional terrace systems are examined, with particular reference to crustal properties, which are shown to have had an important influence on landscape and drainage evolution in the region.
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