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Accueil du site → Doctorat → Allemagne → 2004 → Mineralogical, geochemical and palaeoclimatic characterisation of the Thar desert playas, Rajasthan (India)

Karlsruhe Universität (2004)

Mineralogical, geochemical and palaeoclimatic characterisation of the Thar desert playas, Rajasthan (India)

Roy, Priyadarsi Debajyoti

Titre : Mineralogical, geochemical and palaeoclimatic characterisation of the Thar desert playas, Rajasthan (India)

Auteur : Roy, Priyadarsi Debajyoti

Université de soutenance : Karlsruhe, Univ., Diss., 2004

Résumé
Morphological and sedimentological evidences indicate that the deserts of the world have experienced significant episodic expansions and contractions during Quaternary period. During this period, the sedimentological record of arid zone expansion and contraction is often complemented by morphological evidences, in the form of features such as degraded or fossilized sand dunes, alluvial fans and paleo-lakes. Like dunes, evaporite deposits in paleo-lakes are an important component of many arid and semi arid environments. Given the nature of hydrological input in an arid and semi arid region, it is not surprising that many are characterized by endorheic drainage and lack integrated surface drainage. Under these circumstances surface depressions become important local and regional foci for accumulation of water in lakes. Frequently these water bodies, termed as playas are highly saline and in some cases supersaturated with salt. The precipitation of these salts in playa environments can result from variation in evaporation rates and surface water conditions. Although the minerals in playa salt deposits are somewhat dependent upon chemistry of inflowing waters, differences in evaporite deposits can yield information about the degree of salinity (palaeo-salinity) and hence evaporation rates during past period of playa sedimentation.

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