干旱区生态环境知识资源中心

The international projects involved in the study of environmental and climatic evolution generally do not consider macropalaeontological evidence although the latter can yield important quantifiable data (temperature, soil humidity, precipitation, biomass and oceanic currents) similar to other sources of data taken into account in those research programmes (lacustrine sediments, ocean floor cores, ice cores, corals, loess, pollen, paleosols, sedimentary rocks, dendrochronology and historical evidence). Four examples are given: 1) study of marine, lacustrine and terrestrial molluscs: changes in the intensity of the Canaries current and of upwelling along the coast of western Sahara: presence of palaeolakes in hyperarid Sahara and accurate dating of their evolution, salinity estimations, quantification of Holocene rainfall; 2) study of fish from lacustrine deposits and middens (kjokkenmoddings) of a presently hyperarid area in North Mali: palaeohydrology, existence of surface connections with the Niger basin, water dynamics: 3) study of large fossil Mammals from the Taoudenni basin: existence during the Holocene of a grassland steppe and of important surface water supplies as far north as 22-degrees-23-degrees-N (confirmed several years latering by the coring into lake sections with an important pollen content, which is rare in arid zones), estimate of palaeoprecipitations; 4) discovery of Holocene cromagnoid human remains at 20-degrees-N in Mali: possibility of migrations between 8,500 and 7,000 years B.P. across the presently hyperdesertic belt, at latitudes near the Tropic of Cancer.

Macropalaeontology should be integrated into the international research programmes on global climatic changes.