Thermal evolution of the lithosphere beneath the western Pannonian Basin: evidence from deep-seated xenoliths

A series of recently and previously collected peridotite xenolith samples from the western Pannonian Basin has intensively been studied using electron microprobe techniques and a thermo-barometric approach in order to obtain relevant information about the thermal evolution of the lithosphere. Most of the xenoliths have chemically homogeneous mineral phases reflecting ambient equilibrium P-T conditions. The results indicate hot and thinned lithosphere in agreement with heat Row, seismic and magnetotelluric properties of the area. A strong relationship has been observed between deformation and temperatures of peridotites, in as much as coarse-grained protogranular and poikilitic xenoliths have high temperatures (up to 1175 degreesC), whereas fine-grained equigranular and mosaic xenoliths have low temperatures (800-900 degreesC). This picture suggests that diapiric uplift of hot mantle material into a cooler uppermost mantle has probably taken place. (C) 2001 Elsevier Science B.V. All rights reserved.