Vincent Lignier

Bathymetry and Sedimentary Environments of Lake Issyk-Kul, Kyrgyz Republic (Central Asia): A Large, High-Altitude, Tectonic Lake

Lake Issyk-Kul, located in the northern Tien Shan of the Kyrgyz Republic, in the heart of Central Asia, is one of the deepest and largest lakes in the world. Although Kyrgyz and Russian scientists have studied the lake quite intensively since the 1850’s, not much of the scientific literature has found its way to the international community. It is only recently that Lake Issyk-Kul has also started to attract international attention, and this is essentially thanks to the fact that the area occupies a potentially interesting location for paleoclimate research as well as for geodynamic studies.

Caractérisation géométrique et texturale de perturbations synsédimentaires attribuées à des séismes, dans une formation quaternaire glaciolacustre des Alpes (« les Argiles du Trièves »)

Abstract Synsedimentary soft deformations have disturbed Quaternary lacustrine layered sediments, the ‘Argiles du Trieves’ formation. These structures have been investigated in order to characterise their possible seismic origin. Grain size and composition of respectively disturbed and undisturbed layers do not exhibit any major differences, they indicate a relatively quiet depositional environment. Morphological investigations on these disturbed levels reveal shaking processes. These investigations show structures similar to analogical modelling results, consisting of granular and natural material submitted to different vibrations. These disturbances could be considered as seismites, a hypothesis in agreement with the geodynamically active setting of Trieves area,

Recent Paleoenvironmental Evolution of Lake Issyk-Kul

Closed lakes located in arid and semi-arid environments are highly sensitive to climate oscillations since small variations in their environmental conditions induce dramatic changes within the lake [1]. The sensivity of these lakes is higher if they are located in the border of biomes, as Lake Issyk-Kul, located between the steppic and high mountains environments [2]. These facts make Lake Issyk-Kul an important ecosystem in order to study its adaptability under the environmental changes occurred in the Central Asia region.