Norman H. Sleep, 2018. "Cratonic basins with reference to the Michigan basin", Cratonic Basin Formation: A Case Study of the Parnaíba Basin of Brazil, M. C. Daly, R. A. Fuck, J. Julià, D.I.M. MacDonald, A. B. Watts
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Seafloor and passive margins gradually subside as a result of thermal contraction of the underlying lithosphere. Thermal subsidence is also an attractive mechanism for the Michigan basin. For subsidence to occur within this previously stable continental region, some mechanism is needed to heat the lithosphere and to reduce the buoyancy of the continental crust. Mechanical stretching of the lithosphere along with its crust does both at the same time. The ponding of plume material beneath the crust supplies heat, but does not directly thin the crust. The British Isles and the Congo basin provide analogies to the Michigan basin. Continental stretching before subsidence is evident within the British Isles and the Congo basin. Stretching is not obvious in Michigan, but undetected rifts extending from the Iapetus break-up margin may exist. A closed region of thin lithosphere beneath the Irish Sea may have trapped hot buoyant material from the Iceland plume; the Michigan basin may have trapped material from an Iapetus age plume near Montreal. Cratonic basins provide information on the tail of the subsidence curve, unlike more ephemeral oceanic crust and passive margins. The poorly resolved tails in the Michigan and the Congo basins are consistent with the time subsidence constant, c. 280 myr predicted by stagnant lid convection formalism.
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Cratonic Basin Formation: A Case Study of the Parnaíba Basin of Brazil
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Cratonic basins are large, distinctive features of the continental crust. They are preferentially developed on thick continental lithosphere, are typically sub-circular in shape and subside over periods of hundreds of millions of years. They are also endowed with significant resources. However, in spite of their location in continental interiors and often well-known geology, the subsidence driving mechanism and tectonic setting of these basins remains controversial.
This volume presents both lithospheric and basin scale datasets acquired specifically to interrogate the tectonic process of cratonic basin formation. Focused on the Silurian to Triassic Parnaíba cratonic basin of Brazil, the papers discuss the results of a multidisciplinary basin analysis project comprising new geophysical, geological and geochemical data. This unique dataset enables the characterization of the lithospheric crust and mantle beneath the Parnaíba Basin, constrains the detailed evolution of the basin itself, and enables comparisons with cratonic basins globally. Several convergent themes emerge providing new and powerful constraints for models of the driving mechanisms of these enigmatic basins.