Depositionally-Induced Magnetic Frequency Variations of a Sandstone Facies from the Copper Harbor Conglomerate of the North American, Mid-Continent Rift at Union Bay, Michigan
DOI:
https://doi.org/10.17307/wsc.v1i1.235Keywords:
Copper Harbor Conglomerate, Mid-Continent Rift, Environmental Magnetism, Hematite, red-beds, magnetic susceptibilityAbstract
Precambrian sandstones were investigated to determine whether deep-time, fluvial red-beds can maintain magnetic variations related to deposition. Using an easily accessible site on Earth, it is possible to define methods that benefit future studies related to magnetic variations as linked to conditions of formation. The study utilized environmental magnetism and cyclostratigraphic techniques to determine magnetic characteristics and susceptibility variation frequencies. Magnetite and hematite were inferred from laboratory measurements and the magnetic fabric agreed with previous paleocurrent observations, suggestive that susceptibility correlates with deposition. Hematite concentration controlled susceptibility: high-susceptibility corresponded with large grain-sizes and cross-bedding, while low-susceptibility was attributed to small grain-sizes and erosional or color boundaries. A statistically-significant, cyclic, susceptibility signal was observed from the stratigraphy, suggesting that susceptibility variations may arise from climatically-induced variations in depositional or post-depositional processes. The observed frequency also supports the capacity for fluvial red-bed deposits to maintain depositional characteristics original to formational processes.
References
Cohen, A. S., Soreghan, M. J., & Scholz, C. A. (1993) Estimating the Age of Formation of Lakes: An Example from Lake Tanganyika, East African Rift System. Geology, 21, 511-514.
Dekkers, M. J. (2001). Rockmagnetism and Paleomagnetism. In Encyclopedia of Life Support Systems. (Vol. II, 1-3) Utrecht, Netherlands: Geophysics and Geochemistry.
Elmore, R. D., & van der Voo, R. (1982). Origin of Hematite and its Associated Remanence in the Copper Harbor Conglomerate (Keweenawan), Upper Michigan. Journal of Geophysical Research, 87(B13), 918-928.
Elmore, R. D. (1984). The Copper Harbor Conglomerate: A Late Precambrian Fining-Upward Alluvial Fan Sequence in Northern Michigan. Geological Society of America Bulletin, 95, 610-617.
Egli, R. (2003). Analysis of the Field Dependence of Remanent Magnetization Curves. Journal of Geophysical Research, 108(B2), 1-25.
Hargraves, R. B., Johnson, D., and Chan, C. Y. (1991). Distribution Anisotropy: The Cause of AMS in Igneous Rocks? Geophysical Research Letters, 18, 2193-2196.
Harrison, J. E. (1972). Precambrian Belt Basin of Northwestern United States: Its Geometry, Sedimentation, and Copper Occurrences. Geological Society of America Bulletin, 83, 1215-1240.
Hays, J. D., Imbrie, J., & Shackleton, N. J. (1976). Variations in the Earth's Orbit: Pacemaker of the Ice Ages. Science, 194(4270), 1121-1132.
Heslop, D. (2015). Numerical Strategies for Magnetic Mineral Un-Mixing. Earth-Science Review, 150, 256-284.
Heslop, D., & Dillion, M. (2007). Unmixing Magnetic Remanence Curves without a Prior Knowledge. Geophysics Journal International, 170, 556-566.
Heslop, D., Dekkers, M. J., Kruiver, P. P., & van Oorschot, I. H. (2002). Analysis of Isothermal Remanent Magnetization Acquisition Curves Using the Expectation-Maximization Algorithm. Geophysical Journal International, 148(1), 58-64.
Kodama, K.P. (2016). Rock Magnetic Cyclostratigraphy of the Mississippian Mauch Chunk fm. Pottsville, Pennsylvania, Abstract GP51D-05, presented at 2016 AGU Fall Meeting, San Francisco CA, 12-16, Dec.
Kodama, K. P., & Hinnov, L. A. (2015). Rock Magnetic Cyclostratigraphy. Chichster West Sussex, England: John Wiley & Sons.
Kodama, K. P., Anastasio, D. J., Newton, M. L., Pares, J. M., & Hinnov, L. A. (2010). High-Resolution Rock Magnetic Cyclostratigraphy in an Eocene Flysch, Spanish Pyrenees. Geochemistry, Geophysics, Geosystems, 11, 1-22.
Kruiver, P. P., Dekkers, M. J., & Heslop, D. (2001). Quantification of Magnetic Coercivity Components by the Analysis of Acquisition Curves of Isothermal Remanent Magnetization. Earth and Planetary Science Letters, 189, 269-276.
Liu, Q., Roberts, P. A., Larrasoana, J. C., Banerjee, S. K., Guyodo, Y., Tauxe, L., & Oldfield, F. (2012). Environmental Magnetism: Principles and Applications. Reviews of Geophysics, 50 (RG4002), 1-50.
Mantua, N. J. & Hare R. S. (2002). The Pacific Decadal Oscillation. Journal of Oceanography, 58, 35-44.
Malone, S. L., Staudhammer, C. L., Oberbauer, S. F., Olivas, P., Ryan, M. G., Schedlbauer, J. L., Loescher, H. W., Starr, G. (2014). El Niño Southern Oscillation (ENSO) Enhances CO2 Exchange Rates in Freshwater Marsh Ecosystems in the Florida Everglades. PLOS ONE 9(12), 1-30.
Maxbauer, D. P., Feinberg, J. M., & Fox, D. L. (2016). MAX UnMix: A Web Application for Un-mixing Magnetic Coercivity Distributions. Computers and Geosciences, 95, 140-145.
Ojakangas, R. W., Morey, G. B., & Green, J. C. (2001). The Mesoproterozoic Midcontinent Rift System Lake Superior Region, USA. Sedimentary Geology (141-142), 421-442.
Olsen, P. E., Kent, D. V., Cornet, B., Witte, W. K., & Schlische, R. W. (1996). High-Resolution Stratigraphy of the Newark Rift Basin (early Mesozoic, Eastern North American). Geological Society of America Bulletin, 108(1), 40-77.
Robertson, D. J., & France, D. E. (1994). Discrimination of Remanence-Carrying Minerals in Mixtures Using Isothermal Remanent Magnetization Acquisition Curves. Physics of the Earth Planetary Interiors, (82), 223-234.
Stockhausen, H. (1998). Some New Aspects for the Modelling of Isothermal Remanent Magnetization Acquisition Curves by Cumulative log Gaussian Functions. Geophysical Reserarch Letters (25), 2217-2220.
Vrazo, M. B., Benton, M. J., Daeschler, E. B. (2007). Tetrapod tracks from the Mauch Chunk Formation (middle to upper Mississippian) of Pennsylvania, U.S.A. The Academy of Natural Sciences of Philadelphia, 156(1), 199-209.
Wolff, R. G., & Huber, N. K. (1973). The Copper Harbor Conglomerate (Middle Keweenawan) on Isle Royale, Michigan, and its Regional Implications. Geological Survey Professional Paper 754-B, United States Department of the Interior. Washington D.C.
Downloads
Additional Files
Published
How to Cite
Issue
Section
License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
