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Coastal Dunefields |
Department of Geography, King’s College, Strand, London WC2R 2LS, UK
Since the mid-1960s a number of models (as exemplified by Gavish & Friedman (1969) and Land et al. (1967)) have been developed which suggest that a progressive sequence of morphological, mineralogical and chemical changes occurs during carbonate diagenesis in the vadose zone. The models raise the possibility that the degree of cementation and diagenetic alteration can be used as a guide to interpreting the relative, and even the absolute, age of deposits. A study of the early vadose diagenesis of a wide range of late Quaternary age aeolianites from Oman, South India, the Bahamas, Tunisia and Mallorca has been undertaken to assess the wider applicability of the models. The results presented in this paper indicate that the rigid application of such models to areas outside those for which they have been developed is inappropriate. In the aeolianites analysed, spatial and temporal heterogeneity is the key characteristic. All tend towards an end point of low-Mg calcite allochems and meniscus, rim and pore-filling cement types but at different rates in different places, both locally and regionally, and via several different diagenetic routes.
