Facies and structural contrasts across Bonne Bay cross-strike discontinuity, western Newfoundland

Cawood, Peter A.; Botsford, Jack W.

doi:10.2475/ajs.291.8.737

Cited by 12 publications

(4 citation statements)

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“…Slope deposits in the Humber Arm allochthon (Fig. 2) along segments 3 and 5 consist of coarse Middle Cambrian passive-margin carbonate debris fl ows (Cow Head Group) that grade upward into Middle Ordovician fl ysch (James and Stevens, 1986;Cawood and Botsford, 1991). Outcrops of Neoproterozoic-Early Cambrian synrift slope deposits are lacking in the Humber Arm allochthon along segments 3 and 5, suggesting little or no deposition on the Laurentian slope along these segments during the Early Cambrian (Lavoie et al, 2003).…”

Section: Northern Appalachain Rifted Marginmentioning

confidence: 96%

“…3). The boundaries between each of the fi ve segments on the St. Lawrence promontory are abrupt along-strike discontinuities in shelf on June 7, 2015 geology.gsapubs.org Downloaded from and slope stratigraphy (Cawood and Botsford, 1991). These abrupt along-strike changes in the stratigraphy are interpreted to mark transforms that separate upper-and lower-plate margins along the St. Lawrence promontory.…”

Section: Rifted Margin As a Low-angle Detachment Rift Systemmentioning

confidence: 98%

“…These abrupt along-strike changes in the stratigraphy are interpreted to mark transforms that separate upper-and lower-plate margins along the St. Lawrence promontory. Cawood and Botsford (1991) originally recognized these transforms on the basis of along-strike discontinuity in the passive-margin and foreland-basin slope stratigraphy, and we adopt their nomenclature for these transform faults.…”

Section: Rifted Margin As a Low-angle Detachment Rift Systemmentioning

confidence: 99%

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Stratigraphy and structure of the Laurentian rifted margin in the northern Appalachians: A low-angle detachment rift system

Allen

Thomas

Lavoie

2009

Geology

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The Neoproterozoic-Early Cambrian rifted margin of eastern Laurentia is framed by promontories and embayments defi ned by northeast-trending rifts offset by northwesttrending transforms. A regional fi rst-order synthesis of the available stratigraphic data in the northern Appalachians reveals signifi cant along-strike variations in the thickness, composition, age, and facies of synrift and early postrift stratigraphy. These variations are consistent with models for low-angle detachment rift systems and allow for resolution of regional structures specifi c to low-angle detachments, including upper-plate margins, lower-plate margins, and transform faults that bound zones of oppositely dipping low-angle detachments.

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Section: Northern Appalachain Rifted Marginmentioning

confidence: 96%

Section: Rifted Margin As a Low-angle Detachment Rift Systemmentioning

confidence: 98%

Section: Rifted Margin As a Low-angle Detachment Rift Systemmentioning

confidence: 99%

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Stratigraphy and structure of the Laurentian rifted margin in the northern Appalachians: A low-angle detachment rift system

Allen

Thomas

Lavoie

2009

Geology

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“…The Humber passive margin in Newfoundland is part of the St. Lawrence promontory and segmented by the Serpentine Lake, Bonne Bay, Canada Bay, and Belle Isle transform fault systems (figs. 1B, 2A, 2B, Allen et al, 2009Allen et al, , 2010Cawood & Botsford, 1991;Williams, 1979). Mafic to felsic igneous rocks in the St. Lawrence promontory and Quebec embayment, including those along the Serpentine Lake, Bonne Bay, and Sept Îles transforms (fig.…”

Section: Ediacaran To Cambrian Stratigraphymentioning

confidence: 99%

Late Ediacaran to Early Cambrian Breakup Sequences and Establishment of the Eastern Laurentian Passive Margin, Newfoundland, Canada

Soukup,

Beranek,

Lode

et al. 2024

American Journal of Science

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Sediment provenance studies were conducted to constrain the establishment of the eastern Laurentian or Humber passive margin in Newfoundland, Canada, and examine models for the opening of the Iapetus Ocean and Humber Seaway. Ediacaran to Cambrian Series 2 strata of the lower Labrador and Curling groups contain garnet, muscovite, and feldspar, and yield 1000–1500 Ma detrital zircon grains that reflect local derivation from Grenville Province basement rocks during regional extensional deformation. Cambrian Series 2 to early Miaolingian units of the upper Labrador and Curling groups are quartz-rich and characterized by 556–586 Ma and 1000–2700 Ma detrital zircon grains that instead reflect continental-scale drainage and transition to passive margin deposition along eastern Laurentia. The geological relationships along the Humber margin are compared with modern analogues in the Newfoundland-west Iberia rift system to propose a magma-poor rift model that includes two breakup sequences which formed in response to isostatic adjustment after the rupture of crust and mantle, respectively. Crustal breakup resulted in an Ediacaran to Cambrian Series 2 breakup sequence that was connected to hyperextension, mantle exhumation, and bimodal magmatism. Mantle breakup likely occurred >20 Myr after first mantle exhumation and resulted in a breakup sequence that is best characterized by Cambrian Series 2 to early Miaolingian strata. The mantle breakup sequence consists of regressive-transgressive cycles that record the transition from breakup to thermal subsidence and was probably driven by the separation of the Dashwoods microcontinent from eastern Laurentia and outboard opening of west Iapetus. The Humber Seaway opened between the Humber margin and Dashwoods and was at least partially underlain by exhumed continental mantle. Our scenarios support hypotheses for equivalent magma-poor rift elements elsewhere in the Caledonian-Appalachian orogen, and we predict that crustal and mantle breakup sequences are exposed in the Scotland-Ireland and Quebec-New England segments of the eastern Laurentian margin.

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Lateral Heterogeneity in Compressional Mountain Belt Settings

Giri

Hubbard

2023

Compressional Tectonics

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Facies and structural contrasts across Bonne Bay cross-strike discontinuity, western Newfoundland

Cited by 12 publications

References 0 publications

Stratigraphy and structure of the Laurentian rifted margin in the northern Appalachians: A low-angle detachment rift system

Stratigraphy and structure of the Laurentian rifted margin in the northern Appalachians: A low-angle detachment rift system

Late Ediacaran to Early Cambrian Breakup Sequences and Establishment of the Eastern Laurentian Passive Margin, Newfoundland, Canada

Lateral Heterogeneity in Compressional Mountain Belt Settings

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