New methodologies for investigating rillenkarren cross-sections: a case study at Lluc,Mallorca

Precise data on the detailed form of 108 rillenkarren (flute) cross-sections at Lluc have been obtained by digitizing photographic enlargements of profile gauge traces taken in the field. Such data enable morphometric analysis to be undertaken more rigorously and on a wider range of characteristics (e.g. flute and cusp asymmetry, surface roughness and the properties of vertical sections) than in previous studies. Methods for quantifying and investigating these characteristics are presented. Since many of the flutes were found to be asymmetrical, the two ‘sides’ of each flute have been analysed separately. Although most of the sides have characteristic parabolic profiles, about one-fifth are rectilinear in form. The parabolic sides are relatively smooth, and this is thought to be attributable to dissolution within the thin film of water present on the surface during rainfall and/or to the detachment of small protruding fragments of limestone (weathered loose by biological agencies) by raindrop impact. The rectilinear sides have distinctly rougher surfaces and are thought to be truncated or immature forms. Sets of rillenkarren on rock outcrops appear to be in dynamic equilibrium, maintaining their overall form over time, but changing in detail as cusp lines shift, existing flutes are captured and new ones are initiated. © 1998 John Wiley & Sons, Ltd.