The Midcontinent Rift System: A major Proterozoic continental rift

Hinze, William J.; Allen, David J.; Braile, L. W.; Mariano, John

doi:10.1130/0-8137-2312-4.7

Cited by 32 publications

(31 citation statements)

References 91 publications

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“…Line C shows that the Douglas-Obijwa fault on the north side of the basin was the master fault active during rifting, whereas the Keweenaw fault on the south side is subparallel to the base of the volcanic infill (Hinze et al, 1997), indicating it was not a large rift-bounding normal fault during the extensional phase. In contrast, GLIMPCE line A to the east (Fig.…”

Section: Structural Analysismentioning

confidence: 99%

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North America’s Midcontinent Rift: When rift met LIP

et al. 2015

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Rifts are segmented linear depressions that are filled with sedimentary and igneous rocks; they form by extension and often evolve into plate boundaries. Flood basalts, a class of large igneous provinces (LIPs), are broad regions of extensive volcanism formed by sublithospheric processes. Typical rifts are not filled with flood basalts, and typical flood basalts are not associated with significant crustal extension and faulting. North America's Midcontinent Rift (MCR) is an unusual combination, because its 3000-km length formed during a continental breakup event 1.1 Ga, but it contains an enormous volume of igneous rocks that are mostly flood basalt. We show that MCR volcanic rocks are significantly thicker than other flood basalts, due to their deposition in a narrow rift rather than across a broad region, giving the MCR a rift's geom etry but a LIP's magma volume. Structural modeling of seismic-reflection data shows that LIP volcanics were deposited during two phases-an initial rift phase where flood basalts filled a fault-controlled extending basin and a postrift phase where LIP volcanics and sediments were deposited in a thermally subsiding sag basin without associated faulting. The crust thinned during the initial rifting phase and then rethickened during the postrift phase and later compression, yielding the present thicker crust observed seismologically. The restriction of extension to a single normal fault in each rift segment, steeply inward-dipping rift shoulders with sharp hinges, and persistence of volcanism after rifting ended gave rise to a deep flood basalt-filled rift geometry not observed in other presently active or ancient rifts. The unusual coincidence of a rift and LIP arose when a new rift associated with continental breakup interacted with a mantle plume or overrode anomalously hot or fertile upper mantle.

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Section: Structural Analysismentioning

confidence: 99%

“…1A). To the south, the rift is deeply buried by younger sediments, but its two arms are easily traced because the igneous rocks are dense and highly magnetized (King and Zietz, 1971;Hinze et al, 1997). The MCR formed at ca.…”

Section: Introductionmentioning

confidence: 99%

North America’s Midcontinent Rift: When rift met LIP

et al. 2015

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“…This orogenic belt separates the North America Craton from the Atlantic coastal plain to the east and the Gulf coastal plain to the south. Coexisting with convergent boundaries in ENA are divergent belts, such as the Mid Continental Rift system (MCR, Figures 1a and 1b) [ Hinze et al , 1997], the Reelfoot rift [ Ervin and McGinnis , 1975] and the postulated East Continental Rift Complex (ECRC) [ Stark , 1997]. Since the majority of these ancient rifts as well as much of the Ouachita Orogen are buried under thick sediments, geophysical data are indispensable to obtain a better understanding of the tectonic evolution of ENA.…”

Section: Introductionmentioning

confidence: 99%

Ambient seismic noise tomography and structure of eastern North America

Liang

Langston

2008

J. Geophys. Res.

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The time derivative of cross‐correlation functions (CCF) of ambient noise fields recorded by two stations can be approximated as the Green's Function (GF) between the stations. The CCFs are thus used as Peudo‐GFs (dominated by surface waves) to invert for group velocity structure in eastern North America. Stations from two regional networks deployed to monitor the New Madrid Seismic Zone and eastern Tennessee seismic zone, together with stations of the US National Seismic Network, greatly improve tomographic ray coverage. The short period (T = 5 s) group velocity map shows strong correlations with the depth to Precambrian basement. Many subtle local structures can be clearly identified from the velocity map, including the Ozark uplift, Cincinnati Arch, Nashville Dome and the Blue Ridge province of the Appalachians showing relatively high group velocity. The long period (T = 15 s) group velocity map shows strong correlations with regional geology. Ancient rift basins, such as the Mid‐Continent Rift (MCR) system, the Reelfoot rift, the Oklahoma Aulacogen and the Eastern Continent Rift, are associated with low velocity belts along their rift axes. We also find that all major seismic zones in eastern North America, such as the New Madrid seismic zone, Eastern Tennessee seismic zone as well as Ouachita Orogen seismic zone, are approximately located at transition zones separating velocity highs and lows. This observation suggests that those seismic zones may reflect the reactivation of ancient faults associated with continental rift and collision zones.

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“…Alternatively, this evidence could reflect reverberations within the sedimentary column. The intracrustal presence of thick piles of igneous rocks has been inferred in numerous preceding studies, mostly from the high gravity and magnetic anomalies, and in some places, like Lake Superior, via surface exposures and seismic sounding (GLIMPCE and Norpac Tréhu et al, 1991;Hinze et al, 1997]). …”

Section: Discussionmentioning

confidence: 99%

DISTINCT CRUSTAL STRUCTURE OF THE NORTH AMERICAN MID-CONTINENT RIFT FROM P WAVE RECEIVER FUNCTIONS

Lee¹,

Zhang²,

Wolin³

et al. 2016

Geological Society of America Abstracts With Programs

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Eighty-two broadband seismic stations of the Superior Province Rifting Earthscope Experiment (SPREE) collected 2.5 years of continuous seismic data in the area of the high gravity anomaly associated with the Midcontinent Rift (MCR). Over 100 high-quality teleseismic earthquakes were used for crustal P wave receiver function analysis. Our analysis reveals that the base of the sedimentary layer is shallow outside the MCR, thickens near the flanks where gravity anomalies are low, and shallows again in the MCR's center where the gravity anomalies peak. This pattern is similar to that found from local geophysical studies and is consistent with reverse faulting having accompanied the cessation of rifting at 1.1 Ga. Intermittent intracrustal boundaries imaged by our analysis might represent the bottom of the MCR's mostly buried dense volcanic layers. Outside the MCR, the Moho is strong, sharp, and relatively flat, both beneath the Archean Superior Province and the Proterozoic terranes to its south. Inside the MCR, two weaker candidate Mohos are found at depths up to 25 km apart in the rift's center. The intermediate layer between these discontinuities tapers toward the edges of the MCR. The presence of this transitional layer is remarkably consistent along the strike of the MCR, including beneath its jog in southern Minnesota, near the Belle Plaine Fault. We interpret these results as evidence for extensive underplating as a defining characteristic of the rift, which remains continuous along the Minnesota jog, where due to its orientation, it is minimally affected by the reverse faulting that characterizes the NNE striking parts of the rift.

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The Midcontinent Rift System: A major Proterozoic continental rift

Cited by 32 publications

References 91 publications

North America’s Midcontinent Rift: When rift met LIP

North America’s Midcontinent Rift: When rift met LIP

Ambient seismic noise tomography and structure of eastern North America

DISTINCT CRUSTAL STRUCTURE OF THE NORTH AMERICAN MID-CONTINENT RIFT FROM P WAVE RECEIVER FUNCTIONS

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