The GLIMPCE seismic experiment: Onshore refraction and wide-angle reflection observations from a fan line over the Lake Superior Midcontinent Rift System

Epili, Duryodhan; Mereu, R. F.

doi:10.1029/gm051p0093

Cited by 10 publications

(11 citation statements)

References 24 publications

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“…Seismic data from the 1963 Lake Superior experiment suggest a crust exceeding 50km depth under the central basin, yet of variable thickness elsewhere (Berry & West 1966). This has been verified by Behrendt et al (1988), Cannon et al (1989), Epili & Mereu (1989); by Trkhu et al…”

Section: Introductionmentioning

confidence: 78%

2-D Tomographic Imaging Across the North American Mid-Continent Rift System

Hamilton

Mereu

1993

Geophysical Journal International

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S U M M A R Y 2-D traveltime tomography was used to model the seismic-velocity structure of the Mid-Continent Rift System underneath Lake Superior. The data set came from Line A of the 1986 Great Lakes International Multidisciplinary Program on Crustal Evolution (GLIMPCE) experiment. In-line data analysed in this study were recorded on four land stations and on five ocean-bottom seismometers. Shot spacing on the 240 km long line was approximately 333 m. Both direct and refraction arrival times were used to image the upper crust before expanding the process to cover greater distances and depths. Crustal thickness was determined using reflection (PmP) data from the Moho. Several known near-surface structures were resolved. An extensive high-velocity zone (7.0-7.2 kms-') under the central basin of the lake was found to be composed of a plume-like structure rising to a depth of approximately 10 km. This plume originates from a broader-based (approximately 50 km) mantle bulge, and probably indicates an area of crustal weakness along the rift. A smaller, less complex intrusion appears under the northern basin of the lake. Moho depths increase from about 36 km under the southern flank to about 55 km under the central basin, decreasing again to about 45 km in the north. There is some evidence in the PmP seismic record that the Moho under the central basin is a disrupted transition zone. The velocity model presented here corroborates this. A stability test applied to the tomography velocity model-along with comparisons to other Line A models-indicate that the result is a reliable and a reasonable representation of the Mid-continent Rift System under Lake Superior. These findings support the theory that this complex structure is part of a failed Keweenawan (1100 Ma) tectonic rifting event.

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Section: Introductionmentioning

confidence: 78%

2-D Tomographic Imaging Across the North American Mid-Continent Rift System

Hamilton

Mereu

1993

Geophysical Journal International

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“…This program involved multichannel seismic reflection studies in the Great Lakes (e.g., Behrendt et al 1988;Green et al 1989;Cannon et al 1989;Hutchinson et al 1992), wide-angle seismic reflection and refraction recordings from air-gun sources (Epili and Mereu 1989;Tr6hu et al 1991), and aeromagnetic surveying (Teskey et al 1991). The reflection profiles show that the rift basins are asymmetric and filled with up to 30 km of rift-related volcanic and sedimentary rocks (Behrendt et al 1988;Green et al 1989).…”

Section: Midcontinent Riftmentioning

confidence: 97%

“…The seismic data also show that the graben bounding faults (e.g., Douglas and Keweenaw faults) were later reactivated as high-angle reverse faults with up to 5 km of throw (Cannon et al 1989). Epili and Mereu (1989) processed wide-angle seismic data recorded in a fan geometry from a GLIMPCE line in eastern Lake Superior. T h i s study found thickened crust and highly disrupted Moho under the rift axis compared with the rift flanks (Epili and Mereu 1989).…”

Section: Midcontinent Riftmentioning

confidence: 99%

“…Epili and Mereu (1989) processed wide-angle seismic data recorded in a fan geometry from a GLIMPCE line in eastern Lake Superior. T h i s study found thickened crust and highly disrupted Moho under the rift axis compared with the rift flanks (Epili and Mereu 1989). Hutchinson et al (1992) reprocessed several GLIMPCE reflection lines using relative true amplitude processing techniques.…”

Section: Midcontinent Riftmentioning

confidence: 99%

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Possible extension of the Midcontinent Rift in west Texas and eastern New Mexico

Adams¹,

Keller²

1994

Can. J. Earth Sci.

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The Midcontinent Rift System forms one of the most prominent gravity features in North America. The recognized geophysical anomaly extends in an arc from southern Oklahoma to Lake Superior and then into southern Michigan. The Midcontinent Rift System was active between 1185–1010 Ma, as indicated in the Lake Superior region by age determinations on intrusive igneous rocks. We suggest that the period of formation of the Midcontinent Rift was also a time of extensive igneous activity in Texas and New Mexico. This activity is represented by intrusions beneath the Central basin platform (Texas and New Mexico), intrusions which crop out at the Pajarito Mountain in the Sacramento Mountains (New Mexico), a basaltic debris flow in the Franklin Mountains (Texas), basalt flows at Van Horn (Texas), and the Crosbyton geophysical anomaly (east of Lubbock, Texas). These bodies and other bodies located by geophysical anomalies and wells drilled into mafic Precambrian rocks may be related to the Midcontinent Rift System. Alternatively this magmatism could be related to Grenville age tectonics in Texas. The mafic igneous rocks in this area form a 530 km diameter Middle Proterozoic igneous province, which formed between 1070 and 1220 Ma. Comparison of the Midcontinent Rift System and its extensions proposed here with the Mesozoic and Cenozoic African rift systems indicates that these features are of comparable scale and complexity.

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“…(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). La profondeur du Moho sous le Front de Grenvilîe déterminée par une réflexion prolongée vers l'Est près de la latitude 46° est estimée à environ 51 km (Milkereit et al, 1990b).…”

Section: Lesunclassified

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

Cheng¹

1999

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The GLIMPCE seismic experiment: Onshore refraction and wide-angle reflection observations from a fan line over the Lake Superior Midcontinent Rift System

Cited by 10 publications

References 24 publications

2-D Tomographic Imaging Across the North American Mid-Continent Rift System

2-D Tomographic Imaging Across the North American Mid-Continent Rift System

Possible extension of the Midcontinent Rift in west Texas and eastern New Mexico

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

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