Crustal structure of the Midcontinent rift system: Results from GLIMPCE deep seismic reflection profiles

Behrend, J. C.; Green, A. G.; Cannon, William F.; Hutchinson, Deborah R.; Lee, M. W.; Milkereit, B.; Agena, W.F.; Spencer, Carl

doi:10.1130/0091-7613(1988)016<0081:csotmr>2.3.co;2

Cited by 110 publications

(54 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A good compilation of Moho depths from previous studies in this area can be found in GRAD et al (Fig. 11, distances 0-350 km) with its inward dipping structures and high velocity lower crust resembles that of the East African and Midcontinent rifts (BEHRENDT et al 1988, Keranen et al 2004. The rift shoulders are characterized by higher than average velocities (6.5 km/s) associated with extended Neoarchean crust intruded by Paleoproterozoic mafic magmatism, whereas the center of the rift is characterized by lower velocities and Paleoproterozoic rift-related volcano-sedimentary rocks (CLGB) and granitoid rocks (CLGC).…”

Section: Discussionmentioning

confidence: 93%

“…We interpret the lowermost high velocity (Vp [ 7 km/s), high vp/vsratio ([1.73) to be composed of mafic material. Similarly to the Midcontinent rift structure (BEHRENDT et al 1988), we interpret the undulating mafic, lower crustal layer to image an underplated part of a failed rift. The high velocity layer is observed in much of the Karelian craton riddled with mafic dykes (KORJA et al 1993).…”

Section: Discussionmentioning

confidence: 99%

“…This has been well documented in failed rifts/aulacogens (Midcontinent rift; BEHRENDT et al 1988) as well as in thrust belts where rifted margins have been stacked back on the extended continent e.g. Appalachians (COCORP;COOK et al 1981), Alps (TRANSALP;BERGE and VEAL 2005).…”

Section: Introductionmentioning

confidence: 99%

“…When a continental plate is placed above a mantle plume, it will be thermally uplifted leading to spreading and thinning of the continental lithosphere. The plume not only leaves traceable geological markers such as wide spread mafic magmatism (continental large igneous provinces (LIPs); ERNST and BUCHAN 2001) and coeval sedimentary basins but also geophysical markers such as thinner crust, high velocity lower crust and high velocity bodies in the upper crust (COFFIN and ELDHOLM 1993;BEHRENDT et al 1988;Keranen et al 2004). Together with the stretched crustal remnants and the fresh magmatic additions, a new stable continental lithosphere is formed either in intracratonic rifts or at passive margins.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Crustal Architecture of the Inverted Central Lapland Rift Along the HUKKA 2007 Profile

Tiira

Janik

Kozlovskaya

et al. 2013

Pure Appl. Geophys.

View full text Add to dashboard Cite

Abstract-We have studied the lateral velocity variations along a partly buried inverted paleo-rift in Central Lapland, Northern Europe with a 2D wide-angle reflection and refraction experiment, HUKKA 2007. The experiment was designed to use seven chemical explosions from commercial and military sites as sources of seismic energy. The shots were recorded by 102 stations with an average spacing of 3.45 km. Two-dimensional crustal models of variations in P-wave velocity and Vp/Vs-ratio were calculated using the ray tracing forward modeling technique. The HUKKA 2007 experiment comprises a 455 km long profile that runs NNW-SSE parallel to the Kittilä Shear Zone, a major deformation zone hosting gold deposits in the area. The profile crosses Paleoproterozoic and reactivated Archean terranes of Central Lapland. The velocity model shows a significant difference in crustal velocity structure between the northern (distances 0-120 km) and southern parts of the profile. The difference in P-wave velocities and Vp/Vs ratio can be followed through the whole crust down to the Moho boundary indicating major tectonic boundaries. Upper crustal velocities seem to vary with the terranes/compositional differences mapped at the surface. The lower layer of the upper crust displays velocities of 6.0-6.1 km/s. Both Paleoproterozoic and Archean terranes are associated with high velocity bodies (6.30-6.35 km/s) at 100 and 200-350 km distances. The Central Lapland greenstone belt and Central Lapland Granitoid complex are associated with a 4 km-thick zone of unusually low velocities (\6.0 km/s) at distances between 120 and 220 km. We interpret the HUKKA 2007 profile to image an old, partly buried, inverted continental rift zone that has been closed and modified by younger tectonic events. It has structural features typical of rifts: inward dipping rift shoulders, undulating thickness of the middle crust, high velocity lower crust and a rather uniform crustal thickness of 48 km.

show abstract

Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Crustal Architecture of the Inverted Central Lapland Rift Along the HUKKA 2007 Profile

Tiira

Janik

Kozlovskaya

et al. 2013

Pure Appl. Geophys.

View full text Add to dashboard Cite

show abstract

“…Les premiers modèles de la structure crustale du bouclier se sont fondés sur ces premières interprétations. (1984-1985; 1987-1990), le projet GLIMPCE était concerné par la structure profonde des Grands Lacs et du (Behrendt et al, 1988). L'épaisseur de la croûte déterminée par GLIMPCE, entre 30 et 36 km, est différente de celle de l'interprétation précédente (Epili et Mereu, 1989;Mereu et al, 1990;Trehu et al, 1991).…”

Section: Lesunclassified

Interprétation des données de flux de chaleur et de gravité dans le Bouclier Canadien /

Cheng¹

1999

View full text Add to dashboard Cite

A random‐walk algorithm for modeling lithospheric density and the role of body forces in the evolution of the Midcontinent Rift

Levandowski

Boyd

Briggs

et al. 2015

Geochem Geophys Geosyst

View full text Add to dashboard Cite

This paper develops a Monte Carlo algorithm for extracting three‐dimensional lithospheric density models from geophysical data. Empirical scaling relationships between velocity and density create a 3‐D starting density model, which is then iteratively refined until it reproduces observed gravity and topography. This approach permits deviations from uniform crustal velocity‐density scaling, which provide insight into crustal lithology and prevent spurious mapping of crustal anomalies into the mantle. We test this algorithm on the Proterozoic Midcontinent Rift (MCR), north‐central United States. The MCR provides a challenge because it hosts a gravity high overlying low shear‐wave velocity crust in a generally flat region. Our initial density estimates are derived from a seismic velocity/crustal thickness model based on joint inversion of surface‐wave dispersion and receiver functions. By adjusting these estimates to reproduce gravity and topography, we generate a lithospheric‐scale model that reveals dense middle crust and eclogitized lowermost crust within the rift. Mantle lithospheric density beneath the MCR is not anomalous, consistent with geochemical evidence that lithospheric mantle was not the primary source of rift‐related magmas and suggesting that extension occurred in response to far‐field stress rather than a hot mantle plume. Similarly, the subsequent inversion of normal faults resulted from changing far‐field stress that exploited not only warm, recently faulted crust but also a gravitational potential energy low in the MCR. The success of this density modeling algorithm in the face of such apparently contradictory geophysical properties suggests that it may be applicable to a variety of tectonic and geodynamic problems.

show abstract

Crustal structure of the Midcontinent rift system: Results from GLIMPCE deep seismic reflection profiles

Cited by 110 publications

References 0 publications

Crustal Architecture of the Inverted Central Lapland Rift Along the HUKKA 2007 Profile

Crustal Architecture of the Inverted Central Lapland Rift Along the HUKKA 2007 Profile

Interprétation des données de flux de chaleur et de gravité dans le Bouclier Canadien /

A random‐walk algorithm for modeling lithospheric density and the role of body forces in the evolution of the Midcontinent Rift

Contact Info

Product

Resources

About