Artificial generation of pseudotachylyte using friction welding apparatus: simulation of melting on a fault plane

摘要: A 150 μm thick fused layer of rock has been produced by rotating two metadolerite core faces against each other at 3000 r.p.m. under an axial load 330 kg for 11 s using friction welding apparatus. Scanning electron microscopy and microprobe analysis reveal that the melt comprises sub-angular to rounded porphyroclasts clinopyroxene, feldspar ilmenite (>20 diameter), derived from host metadolerite, set within a silicate glass matrix. Thermal calculations confirm melting occurred interface mean surface temperatures in excess 1400°C were attained. The shows many textural similarities with pseudotachylyte described fault zones. Morphologically, consists series stacks welded together form ‘build-ups’ oriented right angles surface. There is also evidence gouging, ploughing plucking, as well transfer adhesion material having between faces. velocity attained (0.24 m s−1) duration experiment are comparable velocities rise times typical single jerk earthquakes occurring during stick-slip seismic faulting brittle crust (i.e. slip rates 0.1-0.5 s−1 for, say, 1–10s). In these respects successfully simulated frictional fusion on plane absence intergranular fluid. Power dissipation was about MW m−2, only very low values (e.g. 1–100 m−2 displacement shear stresses 100–1000 bars). This indicates planes should be commonplace. Field evidence, however, does not support this contention. Either being recognized exhumed ancient zones or occurs special circumstances.