Mid-crustal deformation at the southern flank of the Sudbury Basin, central Ontario, Canada

Riller, Ulrich; Schwerdtner, W. M.

doi:10.1130/0016-7606(1997)109<0841:mcdats>2.3.co;2

Cited by 51 publications

(44 citation statements)

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“…4). More specifically, these fabrics formed by fold-detachment of mafic metavolcanic strata from the interface with younger, mechanically more competent, fesic volcanic rocks during intrusion of the Creighton and Murray Plutons (Riller and Schwerdtner 1997). South of this north-dipping interface, which was already identified by Cooke (1948), Huronian rocks are generally characterized by greenschist-metamorphic mineral assemblages.…”

Section: Pre-impact Tectonismmentioning

confidence: 73%

“…1, see also Card et al 1984). Formation of this structural dome, the Sudbury Basin is apparently superimposed on, is either attributed to horizontal crustal extension during Paleoproterozoic continental rifting (Rousell et al 1997;Rousell and Long 1998) or a subsequent phase of transpressive deformation (Riller and Schwerdtner 1997;Riller et al 1999) during the Blezardian orogeny about 2.4-2.2 Ga ago (Stockwell 1982). The latter interpretation is based on the kinematics of deformation associated with mineral fabrics formed under amphibolite-facies metamorphic conditions in mafic Huronian metavolcanic rocks truncated by the Main Mass of the South Range SIC (Fig.…”

Section: Pre-impact Tectonismmentioning

confidence: 98%

“…South of this north-dipping interface, which was already identified by Cooke (1948), Huronian rocks are generally characterized by greenschist-metamorphic mineral assemblages. This may indicate that the interface formed as a north-dipping reverse fault along which granitoid melts ascended into the southern flank of the structural dome (Riller and Schwerdtner 1997). Alternatively, the mechanical interface between mafic and felsic volcanic rocks formed as a south-dipping normal fault that rotated into its present orientation, prior to meteorite impact (Fig.…”

Section: Pre-impact Tectonismmentioning

confidence: 99%

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Structural characteristics of the Sudbury impact structure, Canada: Impact-induced versus orogenic deformation-A review

Riller

2005

Meteoritics &Amp; Planetary Science

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Abstract-Orogenic deformation, both preceding and following the impact event at Sudbury, strongly hinders a straightforward assessment of impact-induced geological processes that generated the Sudbury impact structure. Central to understanding these processes is the state of strain of the Sudbury Igneous Complex, the solidified impact melt sheet, its underlying target rocks, overlying impact breccias and post-impact sedimentary rocks. This review addresses (1) major structural, metamorphic and magmatic characteristics of the impact melt sheet and associated dikes, (2) attempts that have been made to constrain the primary geometry of the igneous complex, (3) modes of impactinduced deformation as well as (4) mechanisms of pre-and post-impact orogenic deformation. The latter have important consequences for estimating parameters such as magnitude of structural uplift, tilting of pre-impact (Huronian) strata and displacement on major discontinuities which, collectively,have not yet been considered in impact models. In this regard, a mechanism for the emplacement of Offset Dikes is suggested, that accounts for the geometry of the dikes and magmatic characteristics, as well as the occurrence of sulfides in the dikes. Moreover, re-interpretation of published paleomagnetic data suggests that orogenic folding of the solidified melt sheet commenced shortly after the impact. Uncertainties still exist as to whether the Sudbury impact structure was a peak-ring or a multi-ring basin and the deformation mechanisms of rock flow during transient cavity formation and crater modification.

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Section: Pre-impact Tectonismmentioning

confidence: 73%

Section: Pre-impact Tectonismmentioning

confidence: 98%

Section: Pre-impact Tectonismmentioning

confidence: 99%

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Structural characteristics of the Sudbury impact structure, Canada: Impact-induced versus orogenic deformation-A review

Riller

2005

Meteoritics &Amp; Planetary Science

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“…In the south, much of the SIC, its Huronian host rocks, post-impact sedimentary rocks, pseudotachylite and Offset Dikes, were affected by orogenic deformation under greenschist-facies and, locally, lower amphibolite-facies metamorphic conditions (Card 1978;Thomson et al 1985;Fleet et al 1987;Riller and Schwerdtner 1997;Riller 2005). This has led to the development of mesoscopic planar and linear metamorphic mineral fabrics in these rocks, which are generally attributed to the Paleoproterozoic Penokean orogeny (e.g., Sims et al 1989).…”

Section: Mineral Fabrics Of the Worthington Dikementioning

confidence: 99%

“…In the Sudbury area, the intensity and metamorphic grade of these fabrics decrease generally towards the north. Planar mineral fabrics strike east to northeast and are either subvertical or dip moderately to steeply southward (Riller and Schwerdtner 1997;Cowan et al 1999).…”

Section: Mineral Fabrics Of the Worthington Dikementioning

confidence: 99%

Differentiation and emplacement of the Worthington Offset Dike of the Sudbury impact structure, Ontario

Hecht

Wittek

Riller

et al. 2008

Meteorit & Planetary Scien

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Abstract-The Offset Dikes of the 1.85 Ga Sudbury Igneous Complex (SIC) constitute a key topic in understanding the chemical evolution of the impact melt, its mineralization, and the interplay between melt migration and impact-induced deformation. The origin of the melt rocks in Offset Dikes as well as mode and timing of their emplacement are still a matter of debate. Like many other offset dikes, the Worthington is composed of an early emplaced texturally rather homogeneous quartz-diorite (QD) phase at the dike margin, and an inclusion-and sulfide-rich quartz-diorite (IQD) phase emplaced later and mostly in the centre of the dike. The chemical heterogeneity within and between QD and IQD is mainly attributed to variable assimilation of host rocks at the base of the SIC, prior to emplacement of the melt into the dike. Petrological data suggest that the parental magma of the Worthington Dike mainly developed during the pre-liquidus temperature interval of the thermal evolution of the impact melt sheet (>1200 °C). Based on thermal models of the cooling history of the SIC, the two-stage emplacement of the Worthington Dike occurred likely thousands to about ten thousand years after impact. Structural analysis indicates that an alignment of minerals and host rock fragments within the Worthington Dike was caused by ductile deformation under greenschist-facies metamorphic conditions rather than flow during melt emplacement. It is concluded that the Worthington Offset Dike resulted from crater floor fracturing, possibly driven by late-stage isostatic readjustment of crust underlying the impact structure.

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Deformation, metamorphism, and mobilization of Ni–Cu–PGE sulfide ores at Garson Mine, Sudbury

et al. 2013

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Mid-crustal deformation at the southern flank of the Sudbury Basin, central Ontario, Canada

Cited by 51 publications

References 0 publications

Structural characteristics of the Sudbury impact structure, Canada: Impact-induced versus orogenic deformation-A review

Structural characteristics of the Sudbury impact structure, Canada: Impact-induced versus orogenic deformation-A review

Differentiation and emplacement of the Worthington Offset Dike of the Sudbury impact structure, Ontario

Deformation, metamorphism, and mobilization of Ni–Cu–PGE sulfide ores at Garson Mine, Sudbury

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