High- and ultrahigh-pressure rocks occur in the Austroalpine Nappes a ~400 km long belt from Texel Complex west to Sieggraben Unit east. Garnet growth during pressure increase was dated using Lu-Hf chronometry. The results range between c. 100 90 Ma, indicating short-lived period of subduction. Combined with already published data, our estimates metamorphic conditions indicate field gradient in...

Thermodynamic calculations for selected silicate-oxide-fluorite assemblages indicate that several commonly occurring fluorite-bearing assemblages are restricted to relatively narrow fo,-fF> fields at constant P-T. The presence of fayalite-ferrohedenbergite-fluorite-quartz *magnetite and ferrosalite-fluorite-quartz-magnetite assemblages in orthogneisses from Au Sable Forks, Wanakena and Lake Ple...

Seven eclogite facies samples from lithologically different units which structurally underlie the Semail ophiolite were dated by the Ar/Ar and Rb–Sr methods. Despite extensive efforts, phengite dated by the Ar/Ar method yielded saddle, hump or irregularly shaped spectra with uninterpretable isochrons. The total gas ages for the phengite ranged from 136 to 85 Ma. Clinopyroxene–phengite, epidote–...

Single detrital monazite grains from the Dharamsala and Lower Siwalik Formations (early to mid-Miocene continental foreland basin sediments in NW India) have been dated by two techniques; isotope dilution thermal ionization multicollector mass spectrometry (ID-TIMS) and laser ablation plasma ionization multicollector mass spectrometry (LA-PIMMS). The results give U–Th–Pb isotopic ages of c. 400...

Shock metamorphism in ordinary chondrites allows for reconstructing impact events between asteroids the main asteroid belt. Shock-darkening of occurs at onset complete shock melting rock (>70 GPa) or injection sulfide and metal melt into cracks within solid silicates (\sim 50 GPa). Darkening masks diagnostic silicate features observed reflectance spectrum S-complex so they appear similar to C/X...