Trans-Hudson orogen and Williston basin in Montana and North Dakota: New COCORP deep-profiling results

Nelson, K. D.; Baird, D. J.; Walters, J. J.; Hauck, M.; Brown, L. D.; Oliver, J. E.; Ahern, J. L.; Hajnal, Z.; Jones, Alan G.; Sloss, L. L.

doi:10.1130/0091-7613(1993)021<0447:thoawb>2.3.co;2

Cited by 55 publications

(39 citation statements)

References 8 publications

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“…Solutions of Euler equation give depths near 30km for this feature to the south. This is in agreement with the interpretation of seismic profiles of CO-CORP [Nelson et al, 1993] and LITHOPROBE [Lucas et al, 1994]. The Tabbernor Tabbernor fault is N=0.5 to 1.5, ZQ = 8 to 27 km and a constant phase of 50° in the West direction.…”

Section: Depth To Magnetic Basementsupporting

confidence: 75%

Analysis of gravity and magnetic fields in the Canadian Shield using standard and wavelet-based methods

Bourlon¹

2004

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Section: Depth To Magnetic Basementsupporting

confidence: 75%

Analysis of gravity and magnetic fields in the Canadian Shield using standard and wavelet-based methods

Bourlon¹

2004

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“…Archean rocks of the Sask Craton can be traced discontinuously southward under Phanerozoic cover using regional aeromagnetic data (Geological Survey of Canada, GSC) and Sm-Nd T DM ages from drill cores (Collerson et al 1990). On the Consortium for Continental Reflection Profiling (COCORP) seismic line through Montana and North Dakota, the similarly profiled Dakota block appears broadly correlative with the Sask Craton (Nelson et al 1993;Baird et al 1996).…”

Section: Introductionmentioning

confidence: 94%

The Pelican Thrust Zone: basal detachment between the Archean Sask Craton and Paleoproterozoic Flin Flon Glennie Complex, western Trans-Hudson Orogen

Ashton¹,

Lewry²,

Heaman³

et al. 2005

Can. J. Earth Sci.

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The Pelican Thrust Zone is a 3-7 km-wide recrystallized mylonite zone, along which Paleoproterozoic arc volcano-plutonic and derived sedimentary rocks of the Flin Flon -Glennie Complex were thrust over an Archean package (Jan Lake Complex) consisting of ca. 3.1 Ga calc-alkaline orthogneisses, pelitic migmatites, and a ca. 2.45 Ga tholeiitic charnockite-norite intrusive suite. A regional northeast-plunging stretching lineation and a variety of kinematic indicators imply southwesterly transport, matching that of other coeval shallower crustal-level structures observed throughout the northern Flin Flon Domain and southern flank of the Kisseynew Domain (e.g., Sturgeon-Weir and Annabel Lake shear zones). Subsequent east-side-up displacement on the Tabbernor Fault, together with domal fold interference, has exposed the Pelican Window and mantling mylonite zone, where it has been seismically profiled along Lithoprobe transects. Tectonic windows also expose Archean rocks in the Glennie Domain to the west, where similar southwest-verging, recrystallized mylonite zones have been documented. Together, these zones record collision and underplating of the Flin Flon -Glennie Complex by the Archean Sask Craton during prolonged protocontinent-continent collision over a minimum 1826-1805 Ma interval.Résumé : La zone de chevauchement Pelican est une zone de mylonite recristallisée, d'une largeur de 3-7 km, le long de laquelle des roches volcano-plutoniques d'un arc datant du Paléoprotérozoïque et des roches sédimentaires dérivées du complexe de Flin Flon -Glennie ont été chevauchées par-dessus un ensemble archéen (le complexe de Jan Lake) qui est composé d'orthogneiss calco-alcalins et de migmatites pélitiques (âgées d'environ 3,1 Ga) ainsi que d'une suite intrusive charnockite-norite tholéiitique (âgée d'environ 2,45 Ga). Une linéation régionale d'étirement, à pendage nord-est et divers indicateurs cinématiques correspondent à un transport vers le sud-ouest, rejoignant celui d'autres structures contemporaines de niveaux crustaux moins profonds observées à travers tout le domaine de Flin Flon nord et le flanc sud du domaine Kisseynew (p. ex. les zones de cisaillement de Sturgeon-Weir et d'Annabel Lake). Un déplacement subséquent, le côté est vers le haut, le long de la faille de Tabbernor, avec une interférence de plis de dôme, a fait affleurer la fenêtre Pelican et la zone mylonitique qui la recouvre; elle a été déterminée par des profils sismiques le long des transects Lithoprobe. Des fenêtres tectoniques permettent aussi l'affleurement de roches archéennes du domaine de Glennie, vers l'ouest, là où ont été documentées des zones semblables de mylonites recristallisées à pendage sud-ouest. Ensemble, ces zones enregistrent la collision et le sous-placage du complexe de Flin Flon -Glennie par le craton archéen Sask au cours d'une collision prolongée entre le protocontinent et le continent au cours d'un intervalle d'au moins 1826 à 1805 Ma.[Traduit par la Rédaction] Ashton et al. 706

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“…A strong seismic reflection would be expected to be coincident with the resistivity contrast if there were large amounts of fluid-filled fractures or accumulations of sulphide minerals (e.g. Nelson et al 1993), however, no such seismic signal is observed (Chan 2013). In their study of the Figure 15.…”

Section: Discussionmentioning

confidence: 99%

Magnetotelluric imaging of anisotropic crust near Fort McMurray, Alberta: implications for engineered geothermal system development

Liddell¹,

Unsworth

Pek

2016

Geophys. J. Int.

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S U M M A R YViability for the development of an engineered geothermal system (EGS) in the oilsands region near Fort McMurray, Alberta, is investigated by studying the structure of the Precambrian basement rocks with magnetotellurics (MT). MT data were collected at 94 broad-band stations on two east-west profiles. Apparent resistivity and phase data showed little variation along each profile. The short period MT data detected a 1-D resistivity structure that could be identified as the shallow sedimentary basin underlain by crystalline basement rocks to a depth of 4-5 km. At lower frequencies a strong directional dependence, large phase splits, and regions of out-of-quadrant (OOQ) phase were detected. 2-D isotropic inversions of these data failed to produce a realistic resistivity model. A detailed dimensionality analysis found links between large phase tensor skews (∼15• ), azimuths, OOQ phases and tensor decomposition strike angles at periods greater than 1 s. Low magnitude induction vectors, as well as uniformity of phase splits and phase tensor character between the northern and southern profiles imply that a 3-D analysis is not necessary or appropriate. Therefore, 2-D anisotropic forward modelling was used to generate a resistivity model to interpret the MT data. The preferred model was based on geological observations of outcropping anisotropic mylonitic basement rocks of the Charles Lake shear zone, 150 km to the north, linked to the study area by aeromagnetic and core sample data. This model fits all four impedance tensor elements with an rms misfit of 2.82 on the southern profile, and 3.3 on the northern. The conductive phase causing the anisotropy is interpreted to be interconnected graphite films within the metamorphic basement rocks. Characterizing the anisotropy is important for understanding how artificial fractures, necessary for EGS development, would form. Features of MT data commonly interpreted to be 3-D (e.g. out of OOQ phase and large phase tensor skew) are shown to be interpretable with this 2-D anisotropic model.

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Trans-Hudson orogen and Williston basin in Montana and North Dakota: New COCORP deep-profiling results

Cited by 55 publications

References 8 publications

Analysis of gravity and magnetic fields in the Canadian Shield using standard and wavelet-based methods

Analysis of gravity and magnetic fields in the Canadian Shield using standard and wavelet-based methods

The Pelican Thrust Zone: basal detachment between the Archean Sask Craton and Paleoproterozoic Flin Flon Glennie Complex, western Trans-Hudson Orogen

Magnetotelluric imaging of anisotropic crust near Fort McMurray, Alberta: implications for engineered geothermal system development

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Trans-Hudson orogen and Williston basin in Montana and North Dakota: New COCORP deep-profiling results

Cited by 55 publications

References 8 publications

Analysis of gravity and magnetic fields in the Canadian Shield using standard and wavelet-based methods

Analysis of gravity and magnetic fields in the Canadian Shield using standard and wavelet-based methods

The Pelican Thrust Zone: basal detachment between the Archean Sask Craton and Paleoproterozoic Flin Flon  Glennie Complex, western Trans-Hudson Orogen

Magnetotelluric imaging of anisotropic crust near Fort McMurray, Alberta: implications for engineered geothermal system development

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The Pelican Thrust Zone: basal detachment between the Archean Sask Craton and Paleoproterozoic Flin Flon Glennie Complex, western Trans-Hudson Orogen