"The Midcontinent Rift System (MRS) is a major Precambrian magmatic province on the North American continent. It formed when the North American craton began to split apart during the Mesoproterozoic era (1,100 Ma). As a result of the extension and possibly the effects of a rising mantle plume, a thick layer of basalt and numerous reverse and normal faults were formed. The basalt layer is buried below sedimentary formations and makes it difficult for seismic techniques to image. On the other hand, gravity and magnetic methods can be utilized for focused depths, and the basalt layer of the system can be differentiated due to its high density and high susceptibility values. Consequently, joint gravity-magnetic investigations were conducted in this study to investigate the upper crustal structure of the MCR.
Results show that the thickness of the magnetic portion of the basalt layer beneath the Kansas part of the MRS is approximately 9.1 km with a density of 2.9 gr/cm3. Average crustal thickness beneath the MRS is about 47 km which is consistent with results from passive seismic investigations. The layer immediately beneath the basalt layer has a density that is almost identical to that of the basalt layer, but with a near-zero magnetic susceptibility. This layer is interpreted as a basalt layer, but with a temperature that is higher than the Curie point, above which rocks cannot be magnetized"--Abstract, page iii.
Gao, Stephen S.
Liu, Kelly H.
Geosciences and Geological and Petroleum Engineering
M.S. in Geology and Geophysics
Missouri University of Science and Technology
ix, 69 pages
© 2016 Ozgun Kamil Sahin, All rights reserved.
Thesis - Open Access
Sahin, Ozgun Kamil, "Gravity and magnetic investigations of the north-eastern Kansas section of the midcontinent rift system" (2016). Masters Theses. 8084.