Elastic wave velocities, chemistry and modal mineralogy of crustal rocks sampled by the Outokumpu Scientific Drill Hole: evidence from lab measurements and modeling

H. Kern , K. Mengel , K.W. Strauss , T.I. Ivankina , A.N. Nikitin , I.T. Kukkonen

The Outokumpu Scientific Deep Drill Hole intersects a 2500 m deep Precambrian crustal section comprising a 1300 m thick biotite-gneiss series (mica schists) at top, followed by a 200 m thick meta-ophiolite sequence, underlain again by biotite gneisses (mica schists) (500 m thick) with intercalations of amphibolite and meta-pegmatoids (pegmatitic granite). From 2000 m downward the dominating rock types are meta-pegmatoids (pegmatitic granite). Average isotropic intrinsic P- and S-wave velocities and densities of rocks were calculated on the basis of the volume fraction of the constituent minerals and their single crystal properties for 29 core samples covering the depth range 198 m 2491 m. The modal composition of the rocks is obtained from bulk rock (XRF) and mineral chemistry (microprobe), using least squares fitting.

Mots clés: Outokumpu Deep Drill Hole; Modal composition; Measured and calculated elastic properties; Nature of seismic reflections

H. Kern, K. Mengel, K.W. Strauss, T.I. Ivankina, A.N. Nikitin, et al.. Elastic wave velocities, chemistry and modal mineralogy of crustal rocks sampled by the Outokumpu Scientific Drill Hole: evidence from lab measurements and modeling. Physics of the Earth and Planetary Interiors, 2009, 175 (3-4), pp.151. ⟨10.1016/j.pepi.2009.03.009⟩. ⟨hal-00535573⟩