Details

Autor(en) / Beteiligte

• Milkereit, Bernd
• Percival, John A
• White, Don
• Green, Alan G
• Salisbury, Matt H
• Meissner, Rolf
• Brown, Larry
• Franke, Wolfgang
• Seifert, Friedrich
• Dürbaum, Hans‐Jürgen
• Fuchs, Karl

Titel

Seismic Reflectors in High‐Grade Metamorphic Rocks of the Kapuskasing Uplift: Results of Preliminary Drill Site Surveys

Ist Teil von

• Continental Lithosphere: Deep Seismic Reflections, 1991, p.39-45

Ort / Verlag

Washington, D. C: American Geophysical Union

Erscheinungsjahr

1991

Quelle

Wiley Online Library All Obooks

Beschreibungen/Notizen

• The nature and origin of deep‐crustal reflections can be studied in the Kapuskasing uplift of the central Superior Province, where middle to lower crustal rocks breach the surface. High seismic velocities and reflection zones can be traced up dip from near to their normal depths at >20 km to within a few hundred metres of the surface. The gently dipping reflection zones, defined by LITHOPROBE Vibroseis sections, project to a high‐grade metamorphic sequence of interlayered mafic and felsic gneiss and tonalite. Physical property studies of representative rock samples from the study area confirm the presence of high densities and high compressional wave velocities at shallow depths. Additional dynamite high resolution seismic reflection profiling was carried out in 1989 as a preliminary site survey for the Canadian Continental Drilling Program (CCDP). The main goal of the survey was to provide lateral control of the laminated reflections observed at shallow depths on the Vibroseis profiles. The strong reflections seen on the Vibroseis profiles can be traced with confidence into the dynamite profiles. Amplitude‐versus‐offset (avo) studies of these shallow reflections show an amplitude decay with offset that is compatible with a simple model of interlayered mafic, felsic and tonalitic rocks.