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Full-Text Articles in Physical Sciences and Mathematics
Final Inversion Of The Midcontinent Rift During The Rigolet Phase Of The Grenvillian Orogeny, Mark D. Schmitz
Final Inversion Of The Midcontinent Rift During The Rigolet Phase Of The Grenvillian Orogeny, Mark D. Schmitz
Geosciences Faculty Publications and Presentations
Despite being a prominent continental-scale feature, the late Mesoproterozoic North American Midcontinent Rift did not result in the break-up of Laurentia, and subsequently underwent structural inversion. The timing of inversion is critical for constraining far-field effects of orogenesis and processes associated with the rift's failure. The Keweenaw fault in northern Michigan (USA) is a major thrust structure associated with rift inversion; it places ca. 1093 Ma rift volcanic rocks atop the post-rift Jacobsville Formation, which is folded in its footwall. Previous detrital zircon (DZ) U-Pb geochronology conducted by laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) assigned a ca. 950 Ma maximum …
Seismic Wave Attenuation In Carbonates, Ludmila Adam, M. Batzle, K. T. Lewallen, Kasper Van Wijk
Seismic Wave Attenuation In Carbonates, Ludmila Adam, M. Batzle, K. T. Lewallen, Kasper Van Wijk
CGISS Publications and Presentations
The effect of pore fluids on seismic wave attenuation in carbonate rocks is important for interpreting remote sensing observations of carbonate reservoirs undergoing enhanced oil recovery. Here we measure the elastic moduli and attenuation in the laboratory for five carbonate samples with 20% to 30% porosity and permeability between 0.03 and 58.1 mdarcy. Contrary to most observations in sandstones, bulk compressibility losses dominate over shear wave losses for dry samples and samples fully saturated with either liquid butane or brine. This observation holds for four out of five samples at seismic (10–1000 Hz) and ultrasonic frequencies (0.8 MHz) and reservoir …