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The post-Variscan thermal history of the Erzgebirge (Germany) is the result of periods of sedimentary burial, exhumation and superimposed hydrothermal activity. The timing and degree of thermal overprint have been analysed by zircon and apatite (U-Th)/He and apatite fission track thermochronology. The present-day surface of the Erzgebirge was exhumed to a near-surface position after the Variscan orogeny. Thermal modelling reveals Permo-Mesozoic burial to temperatures of up to 80-100°C, although the sedimentary cover thins out towards the north resulting in maximum burial temperatures of less than 40°C. This thermal pattern was locally modified by Cretaceous hydrothermal activity that reset the zircon (UTh)/He thermochronometer along ore veins. The thermal models show no significant regional exhumation during Cenozoic times, indicating that the peneplain-like morphology of the basement is a Late Cretaceous feature.

Abstract-To test different hypotheses of moldavite formation, a major and trace-element study of 25 moldavite tektites and Sm-Nd isotope measurement of three moldavite tektites was completed. The samples were selected from the classical substrewnfields and the newly described locations in Lusatia (Saxony, Germany). Samples with unusual bulk composition were also included. The results c o n f m earlier studies that the variation in the chemical composition can be explained by single impact and through incomplete mixing of at least three lithographical components dominated by one of the three minerals or mineral groups: dolomite, clay minerals and quartz. An additional endmember, possibly a rare Earth's mantle component, containing high Co, Cr and Ni concentrations is also needed to explain the observed variations in compatible elements of some tektites. Volatile element abundances are low but not necessarily the result of selective volatilization.

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