Inversion of the Proterozoic Wernecke basin during tectonic development of the Racklan Orogen, northwest Canada

1994 ◽  
Vol 31 (3) ◽  
pp. 447-457 ◽  
Author(s):  
Marlene Dredge Mitchelmore ◽  
Frederick A. Cook
Keyword(s):  
Seismic Reflection ◽  
Sedimentary Rocks ◽  
Drill Hole ◽  
Seismic Reflection Data ◽  
Potential Field Data ◽  
Eastern Front ◽  
Reflection Data ◽  
Tectonic Development ◽  
Mackenzie Mountains ◽  
Middle Proterozoic

New deep seismic reflection data coupled with regional stratigraphic correlations, drill-hole information, and potential field data are interpreted to provide images of Middle Proterozoic Wernecke Supergroup (meta-)sedimentary layers that were uplifted during tectonic development of the ca. 0.9–1.3 Ga Racklan Orogen in Canada's western Northwest Territories. The reflection data are located at the eastern front of the Mackenzie Mountains portion of the Canadian Cordillera and on the western flank of the Fort Simpson structural trend that is a prominent Proterozoic structure in the subsurface throughout the region. Along three parallel profiles, layers that are correlated with thick Wernecke Supergroup sedimentary rocks produce prominent reflections between about 3.0 and 9.0 s (about 7.5 and 23 km) that were arched prior to deposition of younger Proterozoic (probably Mackenzie Mountains Supergroup) and Phanerozoic sedimentary rocks. The strata are considered to be Wernecke basin sedimentary rocks that were uplifted during deformation associated with the development of the Racklan Orogen.

The Sask Craton and Hearne Province margin: seismic reflection studies in the western Trans-Hudson Orogen

2005 ◽  
Vol 42 (4) ◽  
pp. 403-419 ◽  
Author(s):  
Z Hajnal ◽  
J Lewry ◽  
D White ◽  
K Ashton ◽  
R Clowes ◽  
...  
Keyword(s):  
Seismic Reflection ◽  
Three Dimensional ◽  
Three Dimensional Model ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Regional Tectonic ◽  
Detachment Zone ◽  
Tectonic Development ◽  
Seismic Images ◽  
Basal Detachment

A three-dimensional model of the regional crustal architecture of the western Trans-Hudson Orogen, based on the interpretation of 590 km of deep-sounding seismic reflection data and a comparable length of existing seismic reflection information, is presented. The seismic images identify the regional geometry of the basal detachment zone (Pelican thrust) that separates juvenile allochthonous terranes from the underlying Archean microcontinent (Sask craton). The Sask Craton is inferred to have a minimum spatial extent of over 100 000 km2 with an associated crustal root that extends for 200 km along strike. During terminal collision, complete convergence of the Rae–Hearne and Superior continental blocks was precluded by the presence of the Sask Craton, resulting in the preservation of anomalous amounts of oceanic and associated sedimentary juvenile material. Along regional tectonic strike, consistency of crustal structure across the Rae–Hearne margin – Reindeer zone boundary is established. Several phases of tectonic development, including multistage subduction and continent–continent collision, are inferred for the western margin of the orogen. A bright, shallow (2–3.5 s two-way traveltime) band of reflectivity (Wollaston Lake reflector) imaged over ~150 000 km2 area is inferred to be a large post-orogenic mafic intrusion. A highly reflective, well-defined and structurally disturbed Moho discontinuity is mapped throughout the western Trans-Hudson Orogen. The present-day crustal architecture of the western Trans-Hudson Orogen is described in terms of the tectonic evolution within the region.

Structural interpretation of the Midcontinent Rift in eastern Lake Superior from seismic reflection and potential-field studies

1994 ◽  
Vol 31 (4) ◽  
pp. 619-628 ◽  
Author(s):  
John Mariano ◽  
William J. Hinze
Keyword(s):  
Potential Field ◽  
Seismic Reflection ◽  
Gravity Data ◽  
Lake Superior ◽  
Field Studies ◽  
Continuous Section ◽  
Midcontinent Rift ◽  
Seismic Reflection Data ◽  
Potential Field Data ◽  
Reflection Data

Integrated interpretations of potential-field and GLIMPCE and industry seismic reflection data in eastern Lake Superior reveal the structural and stratigraphic complexity of the Midcontinent Rift in this region. Projection of the Keweenaw fault into southeastern Lake Superior suggested by early potential-field studies is confirmed by seismic reflection data. Analysis of seismic data in conjunction with aeromagnetic anomalies and regional gravity data also reveals a continuous section of basalt in the footwall of the Keweenaw fault. The lateral dimensions of this section vary along the strike of the rift from the center of the basin towards the southern flank. Spatially extensive anticlinal and synclinal features, reverse faults and related drag folds imaged by the reflection and enhanced potential-field data attest to the influence of a late-stage compressional event in this region. East-northeast trending gradients and displacements associated with observed potential-field anomalies and fault traces mapped at the surface also indicate a degree of accommodation perpendicular to the strike of the rift. These trends parallel the prevalent tectonic grain in the adjacent Archean basement rocks, perhaps suggesting that structures within the rift were in part controlled by preexisting crustal features.

Premine study of shallow coal seams using high‐resolution seismic reflection methods

Geophysics ◽  
1991 ◽  
Vol 56 (9) ◽  
pp. 1494-1503 ◽  
Author(s):  
Harvey Henson ◽  
John L. Sexton
Keyword(s):  
High Resolution ◽  
Seismic Reflection ◽  
Roof Rock ◽  
Drill Hole ◽  
Coal Seams ◽  
Borehole Data ◽  
Seismic Line ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Roof Rocks

Geological investigations in the Illinois Basin coalfields have shown that significant differences in safe and economical exploitation of coal depends directly on accurate mapping of the roof rock overlying the seam, as well as on geological structures in the coal measures. In roof rock transition zones above the Herrin (No. 6) coal where the nonmarine Energy shale changes to the Anna shale, a change often occurs from low to high sulfur coal and from low to high stability roof rocks. In many instances, use of borehole data alone is inadequate to locate these features in advance of mining. High‐resolution seismic reflection data collected near Harco, Illinois were used as part of premine planning to help predict roof instability, areas of low sulfur coal, and geologic disturbances. Several faults, channels, and facies changes affecting the Herrin (No. 6) and the Springfield (No. 5) coal seams at depths of 137 m and 167 m, respectively, were interpreted and modeled. One‐ and two‐dimensional synthetic seismograms calculated from geological data from drill holes along the seismic line were used to aid in the interpretion of the seismic reflection data. Results obtained from the high‐resolution reflection survey combined with drill hole information clearly show that use of borehole data alone is inadequate to locate geological features that might affect coal mine operations, even if the boreholes were spaced 25 m apart. Thus, high‐resolution reflection surveying should be employed whenever feasible for the safe and economical exploitation of coal deposits.

Proterozoic deformation beneath Banks Island: implications for the regional extent of the Racklan orogeny

1990 ◽  
Vol 27 (4) ◽  
pp. 605-613
Author(s):  
Frederick A. Cook
Keyword(s):  
Relative Position ◽  
Seismic Reflection ◽  
The South ◽  
Arctic Canada ◽  
Seismic Reflection Data ◽  
Thrust Faulting ◽  
Reflection Data ◽  
Banks Island ◽  
Mackenzie Mountains ◽  
Northeast Corner

Seismic reflection data from the northeast corner of Banks Island in arctic Canada show that Proterozoic layers were subjected to at least two deformational events prior to the Cambrian. The oldest of these events involved folding and faulting(?) from west-northwest to east-southeast. The ages of the layers that were subjected to this deformation are unknown; however, younger Proterozoic layers, probably correlative with the Shaler Group (ca. 1.1–0.8 Ga), unconformably overlie the folded and faulted layers, and were themselves regionally arched prior to the Cambrian. The relative position of the oldest deformed strata is thus the same as that of the strata observed to the south beneath the Anderson Plains, where thrust faulting and folding deformed pre-Mackenzie Mountains Supergroup (Shaler Group equivalent) layers during at the time of the Racklan orogeny (ca. 1.1–1.2 Ga). Distant effects of the Racklan orogeny may therefore extend to at least the northeast side of Banks Island.

The style of transverse faulting in the Dead Sea basin from seismic reflection data: The Amazyahu fault

2006 ◽  
Vol 55 (3) ◽  
pp. 129-139 ◽  
Author(s):  
Avihu Ginzburg ◽  
Moshe Reshef ◽  
Zvi Ben-Avraham ◽  
Uri Schattner
Keyword(s):  
Seismic Reflection ◽  
Dead Sea ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Dead Sea Basin ◽  
The Dead
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