Soil erosion,climatic vagary and agricultural change on the Downs around Lewes and Brighton,autumn 1982

Farmland on the Downs between Lewes and Brighton suffered severe erosion during the autumn of 1982. The erosion was widespread and affected a variety of topographic situations, but it was confined to areas of arable land and recently-sown grass leys. Erosion on the scale recorded during the autumn of 1982 has never previously been recorded from this area. Three major sites of erosion are described and explanations for the erosion are sought through an analysis of rainfall conditions experienced during autumn 1982 and in recent changes in agricultural land use on the Downs. It is concluded that, whilst total rainfall and the intensity of rainstorms were both unusually high, similar events are likely to recur several times a century. Evidence is presented which suggests that the ploughing up of permanent pasture, the removal of field boundaries and the increased adoption of autumn-sown cereals have all contributed to the onset of severe erosion. It appears that a major re-activation of erosion on the Downs may be commencing which threatens the long-term viability of farming in the area.     

Spatio-temporal Organization of Mountain Taiga Geosystems of the Baikal Natural Territory

Results from investigating the geosystems of Cisbaikalia in its western and eastern parts (Primorskii Range and Barguzin Range, respectively) are presented. For studying three macroslopes of these mountain ranges (having an easterly aspect for the Primorskii Range and a westerly and south-easterly aspect for the Barguzin Range), the regional background and the main factors of the landscape differentiation of the study areas were analyzed. Structural features of topological geosystems are revealed, and large-scale maps of key areas are compiled (at a scale of 1:50 000). Maps of the landscape-typological structure were created on the basis of the structural-dynamic and facies analysis of landscapes. It is established that the main factors influencing the landscape diversity are the aspect and steepness of the slopes, the composition and structure of rocks, the absolute height, the amount of atmospheric precipitation, and anthropogenic impacts. It is determined that the influence of the lithomorphic factor is widespread throughout the study areas, the hydromorphic factor is also important, the cryomorphic factor occurs additionally in the goletz zone, and the xeromorphic factor is only observed on the Baikal Range and on the coastal plain in some areas of Priolkhonie. The dynamic aspect of the landscape structure and the relationships between geosystems are displayed in map legends.     

Porphyry Molybdenum Prospectivity in the Zhongdian Arc,SW China: Use of Singularity and Factor Analyses for Resource Assessment

Natural Resources Research - The Zhongdian arc is an important mineral province in southwest China that hosts significant Cu- and Mo-rich ore deposits. These are mainly present as Late Triassic...     

Paleolimnological assessment of human impacts in Lake Blanca, SE Uruguay

Paleolimnological techniques were used to assess human impacts onLake Blanca, a small (0.6 km²), coastal fresh waterbodyin southern Uruguay, which is the drinking water source for 100,000 localresidents. We retrieved a core that extends to about 1100 ¹⁴Cyr BP. ²¹⁰Pb ages, organic mater, CO₃, totalcarbon, nutrients, fossil pigments and diatoms allowed us to establishlimnological conditions before and after cultural impacts. Soil removal(1880–1960) and intensive cattle and sheep grazing (1943–1966) ledto gully formation in the catchment. This watershed erosion resulted inincreased sedimentation rates. The aquatic system appeared to be mesotrophicwith dominance of epibenthic diatoms until 1966, at which timeeutrophication intensified with forestry activities. Increases in nutrients, aswell as blooms of planktonic diatoms, were observed. During the last decade,tourist/urban development as well as high drinking water demand caused areduction in lake area. Subsequent marked increases in rainfall led to furtherphytoplankton blooms and macrophyte proliferation.