OPPORTUNITIES, LIMITATIONS, AND METHODOLOGIES FOR DECIPHERING INFORMATION OF LATE QUATERNARY ENVIRONMENTS FROM DISCONTINUOUS AEOLIAN ARCHIVES

Linear sand dunes and aeolian sand sheets cover massive areas defined as arid. This makes them a potentially valuable archive of late Quaternary regional and local climates and environments, particularly with regard to windiness and vegetation cover. Linear dunes which are relatively uniform in sedimentological composition are often characterized by stratigraphic similarity, especially for linear dune types such as the vegetated linear dune that have been reported to vertically accumulate along their axis. Being sensitive and surficial landforms, vegetated linear dunes and sand sheets record aeolian environments such as rapid phases of sand sedimentation and erosion, periods of stabilization characterized frequently by local sand shifting, and preservation such as by pedogenesis. Thus dune stratigraphies are ubiquitously discontinuous. This talk will outline the opportunities, limitations, and methodologies for deciphering information regarding past environments and climates from such aeolian landforms.

While continuous sedimentological archives often yield valuable palaeoclimatic information from direct interpretations of even sole records, reliable palaeoenvironmental information from vegetated linear dunes can be retrieved only after completing a complex holistic study program. This approach requires strict attention to spatial scale and evenness, geomorphology, site selection, sampling campaign and guidance, dating techniques, age quality, metadata and significance, and interpretation processes. Following this approach, competent chronologies and interpretations of aeolian sedimentation and discontinuities can be of prime importance for highlighting various past conditions and thresholds that may not be fully recognized from continuous palaeoenvironmental archives