Ž . Geomorphology 30 1999 33–52 Classic and new dating methods for assessing the temporal occurrence of mass movements Andreas Lang a, ) , Jose Moya b , Jordi Corominas b , Lothar Schrott c , Richard Dikau c ´ a Forschungsstelle Archaometrie der Heidelberger Akademie der Wissenschaften am MPI-Kernphysik, Postfach 103980, D-69029 ¨ Heidelberg, Germany b Departamento de Ingenierıa del Terreno, E.T.S. Ingenieros de Caminos, UniÕersitat Politecnica de Catalunya, Gran Capitan, s r n. Edifici ´ ` ´ D-2, 08034 Barcelona, Spain c Geographische Institute der UniÕersitat Bonn, Meckenheimer Allee 166, D-53115 Bonn, Germany ¨ Received 30 July 1997; received in revised form 19 November 1997; accepted 17 June 1998 Abstract Establishing landslide chronologies is essential both for understanding causes of mass movements as part of fundamental geomorphological research, and for the assessment of landslide hazards as part of applied geomorphology. We discuss the applicability of different methods for determining landslide chronologies, frequencies and dynamics in relation to the type of material being dated, sampling location and type of mass movement. The emphasis is on the possibilities and limitations of the different dating methods. Established methods such as radiocarbon dating, lichenometry and dendrochronology are briefly discussed. The paper Ž. Ž . focuses, however, on 1 new analytical techniques like Accelerator Mass Spectrometry AMS , Thermally Ionising Mass Ž . Ž. Spectrometry TIMS and laser fusion, which have led to significant improvements of established dating methods and on 2 Ž . Ž . new dating methods like Optically-Stimulated-Luminescence OSL dating and Alpha-Recoil-Track ART dating. q 1999 Elsevier Science B.V. All rights reserved. Keywords: landslides; radiocarbon dating; lichenometry; dendrochronology; cosmogenic nuclides; U-series; Optically-Stimulated-Lumines- cence; precision; accuracy 1. Introduction Historical references are the most reliable sources of data for reconstructing the temporal distribution of landslides. Aerial photographs and old maps hold valuable information concerning the succession of Ž . landslides Brunsden and Jones, 1976 . However, ) Corresponding author. Present address: Geographische Institut der Universitat Bonn, Meckenheimer Allee 166, D-53115 Bonn, ¨ Germany. when historical data are not available, absolute dat- ing of ancient landslides provides the only means of determining their distribution in time. This temporal aspect is important for establishing causes of these mass movements. A clustering during specific peri- ods may be due to specific climatic conditions or to other external triggering factors, such as earthquakes. Precise and accurate age estimates are, however, not easy to obtain. The choice of the most appropriate dating method is not a simple matter and material suitable for dating is often scarce. The selection of a 0169-555Xr99r$ - see front matter q 1999 Elsevier Science B.V. All rights reserved. Ž . PII: S0169-555X 99 00043-4