Longitudinal Petrochemical Variation in the Mackenzie Dyke Swarm, Northwestern Canadian Shield

Baragar, W R A; Ernst, Richard E.; Hulbert, L.; Peterson, T D

doi:10.1093/petrology/37.2.317

Cited by 166 publications

(129 citation statements)

References 32 publications

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“…1) and the lower lavas of the Coppermine River basalts (Copper Creek Formation). Data sources: Bear River dykes: Thorkelson (2000), Schwab and Thorkelson (2001) (Table 1); Coppermine River basalts: Dupuy and Dostal (1992), Baragar et al (1996), Griselin et al (1997); Mackenzie dykes: Gibson et al (1987), Baragar et al (1996). Normalizing values from Sun and McDonough (1989).…”

Section: Geochemistrymentioning

confidence: 99%

“…The Coppermine River basalts generally consist of microphenocrysts of plagioclase and augite with accessory Fe-oxides in an interstitial groundmass of potassium feldspar and quartz (Baragar et al, 1996). The Mackenzie dykes have a similar mineralogy consisting essentially of plagioclase, pyroxenes and Fe-Ti oxides, with quartz, potassium feldspar ± biotite and amphibole in the interstices (Baragar et al, 1996).…”

Section: Correlations With the Mackenzie Igneous Eventmentioning

confidence: 99%

“…Crustal assimilation as a significant influence on the composition of the Coppermine lavas and Mackenzie dykes has been proposed on the basis of major and trace element abundances and Nd isotope geochemistry (Dudás and Peterson, 1992;Dupuy and Dostal, 1992;Dostal et al, 1983;Francis, 1994;Baragar et al, 1996;Griselin et al, 1997). Dykes and flows with strongly negative values of ε Nd(T ) are considered to have undergone significant crustal contamination, a process evident in an individual Mackenzie dyke with ε Nd(T ) values ranging from −0.6 in the interior of the dyke to −9.8 at the margin (Dudás and Peterson, 1992).…”

Section: Correlations With the Mackenzie Igneous Eventmentioning

confidence: 99%

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The Bear River dykes (1265–1269 Ma): westward continuation of the Mackenzie dyke swarm into Yukon, Canada

Schwab

Thorkelson

Mortensen

et al. 2004

Precambrian Research

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The 1.27 Ga Mackenzie dyke swarm, the largest on Earth, radiates from a point in the western Canadian Arctic and extends across much of the Canadian Shield. Possible western extensions of the swarm are largely obscured by younger sedimentary cover. Paleoproterozoic inliers in northern Yukon host the Bear River dykes (BRD), herein dated by U-Pb baddeleyite and zircon methods at 1268.5 ± 1.5 Ma and 1264.6 ± 1.2 Ma. The BRD share similar geochemical and Nd-isotopic characteristics with the Mackenzie dykes and the coeval Coppermine River basalts, and are regarded as products of the same plume. Hydrothermal activity at ∼1270 Ma in breccia of the Nor mineral occurrence, northwest of the BRD, was probably generated by BRD at depth. The BRD generally strike northwest, approximately 90 • to the orientation predicted by the radiating dyke model. This difference may be explained by an anomalous local stress field at the time of BRD emplacement, or reorientation of BRD during subsequent events of Cordilleran deformation. Using the Nor mineral occurrence as the westernmost locale of Mackenzie dyking, and assuming a model of uniform dyke radiation, the arc of the Mackenzie swarm is at least 50 • greater than previously recognized, bringing the total arc of dyke radiation to >150 • .

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Section: Geochemistrymentioning

confidence: 99%

Section: Correlations With the Mackenzie Igneous Eventmentioning

confidence: 99%

Section: Correlations With the Mackenzie Igneous Eventmentioning

confidence: 99%

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The Bear River dykes (1265–1269 Ma): westward continuation of the Mackenzie dyke swarm into Yukon, Canada

Schwab

Thorkelson

Mortensen

et al. 2004

Precambrian Research

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“…The Fe-Ti enrichment is akin to that of high Fe-Ti basalts around the world, such as the ∼1685 Ma mafic rocks in eastern Australia (Raveggi et al, 2007), the ∼1.27 Ga Mackenzie mafic dykes and Coppermine River basalts of Canada (Dostal et al, 1983; Baragar (Winchester and Floyd, 1977). The ∼1685 Ma mafic rocks in Eastern Australia are from Raveggi et al (2007); the ∼1.27 Ga Mackenzie mafic dykes and Coppermine River basalts are from Dostal et al (1983) and Baragar et al (1996Baragar et al ( ). et al, 1996 (Fig.…”

Section: Major and Trace Element Compositionsmentioning

confidence: 99%

“…Two distinct episodes of slightly younger rift magmatism are also identified along both the margins and interiors of these cratons, such as the ∼1.25 Ga and ∼1.21 Ga magmatic events as summarized in Table 4. Although it is generally accepted that a mantle plume is the most feasible explanation for the generation of the ∼1.27 Ga magmatism (Le Cheminant and Heaman, 1989;Ernst and Baragar, 1992;Baragar et al, 1996;Ernst and Buchan, 2001;Ernst et al, 2008) and for the final break-up of the Columbia supercontinent (Zhao et al, 2002a(Zhao et al, ,b, 2004Hou et al, 2008a,b), a protracted 60 Ma long period that includes the youngest magmatic pulse at ∼1.21 Ga is not in agreement with short-lived and voluminous magmatism that characterizes plume-related large igneous provinces. Therefore, they may not be related to the same plume event.…”

Section: Tectonic Implicationsmentioning

confidence: 99%

Mesoproterozoic high Fe–Ti mafic magmatism in western Shandong, North China Craton: Petrogenesis and implications for the final breakup of the Columbia supercontinent

Peng

Wilde

et al. 2013

Precambrian Research

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Effects of crustal-scale mechanical layering on magma chamber failure and magma propagation within the Venusian lithosphere

Corvec

McGovern

Grosfils

et al. 2015

J. Geophys. Res. Planets

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Understanding the connection between shallow subsurface magmatism and related surface expressions provides first-order insight into the volcanic and tectonic processes that shape a planet's evolution. When assessing the role of flexure, previous investigations assumed homogeneous host rock, but planetary lithospheres typically include crust and mantle material, and the mechanical response of a layered lithosphere subjected to flexure may influence both shallow magma reservoir failure and intrusion propagation. To assess the formation of giant radial dike systems, such as those observed on Venus, we create axisymmetric elastic finite element models of a spherical reservoir centered at the contact between stiff, dense mantle overlain by softer, lighter crust. We analyze magma chamber stability, overpressure at rupture, and resulting intrusion types for three distinct environments: lithostatic, upward flexure, and downward flexure. In the lithostatic case, reservoir failure at the crust-mantle contact favors lateral sill injection. In the flexure cases, we observe that failure location depends upon the crust/lithosphere thickness ratio and, at times, will favor radial dike intrusion. Specifically, upward flexure can promote the formation of giant radiating dike swarms, a scenario consistent with a plume-derived origin. Our results present a mechanical explanation for giant radial dike swarm formation, showing that both the stability of magma chambers on Venus and the type of intrusions that form are influenced by lithospheric layering. Furthermore, where dike swarms occur, our approach provides a powerful new way to constrain local crust/mantle layering characteristics within the lithosphere at the time the swarm was forming.

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Longitudinal Petrochemical Variation in the Mackenzie Dyke Swarm, Northwestern Canadian Shield

Cited by 166 publications

References 32 publications

The Bear River dykes (1265–1269 Ma): westward continuation of the Mackenzie dyke swarm into Yukon, Canada

The Bear River dykes (1265–1269 Ma): westward continuation of the Mackenzie dyke swarm into Yukon, Canada

Mesoproterozoic high Fe–Ti mafic magmatism in western Shandong, North China Craton: Petrogenesis and implications for the final breakup of the Columbia supercontinent

Effects of crustal-scale mechanical layering on magma chamber failure and magma propagation within the Venusian lithosphere

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