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Cretaceous Paleomagnetism Of The Methow-Pasayten Belt, Washington, Russ R. Burmester, Myrl E. Beck Jr., Julian L. Granierer
Cretaceous Paleomagnetism Of The Methow-Pasayten Belt, Washington, Russ R. Burmester, Myrl E. Beck Jr., Julian L. Granierer
Geology Faculty Publications
Detailed demagnetization experiments isolated a characteristic remanent magnetization in ten stable sites from the upper Cretaceous Winthrop and Midnight Peak Formation in the Methow-Pasayten belt of north-central Washington. This remanence agrees best between opposite limbs of a fold (the Goat Peak syncline) when corrected for 46% of tilt. This is consistent with magnetization acquired during deformation. Synfolding magnetization may have been facilitated by a thermo-chemical event associated with synkinematic intrusions along the axis of folding. The mean direction (D=12.0°, I=61.1°, Alpha-95=4.8°) is highly discordant with respect to the expected direction for north-central Washington. This discordance points to about 1,400 km …
Paleomagnetism Of Middle Tertiary Volcanic-Rocks From The Western Cascade Series, Northern California, Myrl E. Beck Jr., Russ R. Burmester, Douglas E. Craig, C. Sherman Gromme, Ray E. Wells
Paleomagnetism Of Middle Tertiary Volcanic-Rocks From The Western Cascade Series, Northern California, Myrl E. Beck Jr., Russ R. Burmester, Douglas E. Craig, C. Sherman Gromme, Ray E. Wells
Geology Faculty Publications
The Western Cascade Series (WCS) is a 3.5-km-thick, crudely homoclinal (east dipping) calcalkaline volcanic sequence of mid-Oligocene to early Miocene age that crops out near the southern tip of the Cascade Range in northern California. The mean direction of remanent magnetization in the WCS is D, 4.9°; I, 57.6° (N, 53; k, 14.4; α95 , 5.3°). When compared to a reference direction for the North American cration, the WCS direction indicates that the southern Cascade Range has rotated 14.0° +/- 9.0° since the WCS accumulated. A difference in mean direction between the lower and upper halves of the WCS …
Transient Electromagnetic Sounding For Groundwater, David V. Fitterman, Mark T. Stewart
Transient Electromagnetic Sounding For Groundwater, David V. Fitterman, Mark T. Stewart
Geology Faculty Publications
The feasibility of using the transient electromagnetic sounding (TS or TDEM) method for groundwater exploration can be studied by means of numerical models. As examples of its applicability to groundwater exploration, we study four groundwater exploration problems: (1) mapping of alluvial fill and gravel zones over bedrock; (2) mapping of sand and gravel lenses in till; (3) detection of salt or brackish water interfaces in freshwater aquifers; and (4) determination of hydrostratigraphy. These groundwater problems require determination of the depth to bedrock; location of resistive, high-porosity zones associated with fresh water; determination of formation resistivity to assess water quality; and …