The fluvial history of the Mediterranean basin and the Near East includes depositional evidence for a latitudinally diachronous, locally bipartite, episode of aggradation by equable streams during the period AD 500–1900. According to the Leopold gullying model, the key requirement would have been an increase in the proportion of small, non-erosive rains. Theoretical considerations supported by general climate models suggest that a decrease in solar radiation at the UV wavelengths would lead to equatorward displacement of the subtropical jet streams and the associated mid-latitude depressions. Atmospheric Δ14C values show a gradual decline from c. 7000 bp followed by a temporary resurgence after AD 500 which includes peaks corresponding to the Oort, Wolf, Spörer, Maunder, Dalton and other solar minima. Reduced irradiance could account for channel aggradation by favouring cyclonic at the expense of convectional precipitation. Confirmation of a solar–fluvial link would benefit both solar history and flood forecasting.
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Landscape Evolution: Denudation, Climate and Tectonics over Different Time and Space Scales
The morphology of Earth’s surface reflects the interaction of climate, tectonics and denudational processes operating over a wide range of spatial and temporal scales. These processes can be considered catastrophic or continuous; depending on the timescale of observation or interest. Recent research had required integration of historically distinct subjects such as geomorphology, sedimentology, climatology and tectonics. Together, these have provided new insights into absolute and relative rates of denudation, and the factors that control the many dynamic processes involved. Specific subject areas covered are sediment transport processes and the timescales of competing processes, the role of the geological record and landscapes in constraining different processes, the nature of landscape evolution at different spatial scales and in contrasting geological environments.