TY - JOUR A1 - Brandmeier, Melanie A1 - Kuhlemann, J. A1 - Krumrei, I. A1 - Kappler, A. A1 - Kubik, P.W. T1 - New challenges for tafoni research. A new approach to understand processes and weathering rates JF - Earth Surface Processes and Landforms N2 - Cavernous tafoni-type weathering is a common and conspicuous global feature, creating artistic sculptures, which may be relevant for geochemical budgets. Weathering processes and rates are still a matter of discussion. Field evidence in the type locality Corsica revealed no trend of size variability from the coast to subalpine elevations and the aspect of tafoni seems to be governed primarily by the directions of local fault systems and cleavage, and only subordinately by wind directions or the aspect of insulation. REM analysis of fresh tafone chips confirmed mechanical weathering by the crystallization of salts, as conchoidal fracturing of quartz is observed. The salts are only subordinately provided by sea spray, as calcium and sodium sulfates rather than halite dominate even close to the coast. Characteristic element ratios compare well with aerosols from mixed African and European air masses. Sulfates are largely derived from Sahara dust, indicated by their sulfur isotopic composition. Salt crystals form by capillary rise within the rock and subsequent crystallization in micro-cracks and at grain boundaries inside rain-protected overhangs. Siderophile bacteria identified by raster electron microscopy (REM) analysis of tafone debris contribute to accelerated weathering of biotite and tiny sulfide ore minerals. By applying 10Be-exposure dating, weathering rates of large mature tafone structures were found to be about an order of magnitude higher than those on the exposed top of the affected granite blocks. KW - tafoni KW - Corsica KW - cavernous weathering KW - weathering rates KW - salt weathering KW - 10Be dating Y1 - 2011 U6 - https://doi.org/10.1002/esp.2112 VL - 36 IS - 6 SP - 839 EP - 852 ER -