Paleoclimate Reconstruction in continental settings from calcisols – Lower to Middle Miocene SE France and Central Spain

Calcisols are widely distributed in the fossil continental successions. Due to the interactions between leaching and accumulation processes of chemical elements in the soil profile, classic climofunctions cannot be applied to... [ view full abstract ]

Calcisols are widely distributed in the fossil continental successions. Due to the interactions between leaching and accumulation processes of chemical elements in the soil profile, classic climofunctions cannot be applied to this type of soil.
The Calcisol climofunctions have been developed based on data from modern calcisols (Gillot, 2014). They relate present climate parameters [mean annual precipitation (MAP) and mean annual temperature (MAT)] to the major element concentrations in soil profiles.
Comparison of paleoclimatic reconstructions from the paleosol morphologic characteristics and the climofunctions shows a good agreement. The climofunctions present the advantage to be applied to truncated paleosols whereas well preserved profiles are needed to estimate the MAP. Thus the paleoclimatic reconstruction from paleosol morphology and major element concentration provides us with several parameters such as MAP, MAT and MARP (mean annual range of precipitation.
Application of these climofunctions to the SE France and Central Spain lower to middle Miocene continental successions reveals fairly comparable values between the two regions (MAT between 13 to 19°C and MAP ranging from 250-700 mm/yr). Comparison from paleoclimatic reconstructions from the same period in western Europe (mainly Germany, Portugal, northern Spain) indicates similar temperature, but MAP that are twofold larger than in the studied area.
Such results raise the question of the setting up of a climatic belt as early as lower Miocene in south eastern France and Central Spain, that had later evolved into the modern Mediterranean climate.

Reference : Gillot T. (2014) Apport de l’étude des paleosols carbonatés et des climofonctions spécifiques aux reconstitutions paléoenvironnementales et paléoclimatiques. Application aux séries alluviales oligo-miocènes d’Europe occidentale, PhD thesis, 288p.