Bay of Islands map-area, Newfoundland (12G)

Williams, Harold; Maplas, J; Comeau, Robert

doi:10.4095/123979

Cited by 15 publications

(3 citation statements)

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“…Samples and the basis for emplacement depth assignments are described in detail in and taken from Christensen and Salisbury (1982). Christensen and Salisbury (1982) give depths relative to the sediment‐basalt contact and interpret sediments as conformably overlying the pillow basalts (as also interpreted in the original mapping of Williams, 1973; as well as the work of Malpas, 1977). In contrast, Casey and Kidd (1981) interpreted most of the overlying sediments as forming on top of an erosion surface and thus unrelated to the initial formation of the ophiolite — Casey et al.…”

Section: The Bay Of Islands Ophiolitementioning

confidence: 96%

“…The BOI ophiolite complex (Newfoundland) is a “Penrose” style ophiolite with some massifs (North Arm Mountain and Blow‐Me‐Down Mountain) containing complete sections that include peridotites, gabbros, sheeted dykes, and volcanic rocks (Cawood & Suhr, 1992; Church & Stevens, 1971; Dewey & Casey, 2013; Williams, 1973). It is commonly used as a model for the formation and obduction of ophiolites (Cawood & Suhr, 1992), low‐temperature alteration of igneous rocks (Jacobsen & Wasserburg, 1979; Parendo et al., 2017), as well as a proxy for the properties of oceanic crust (e.g., Christensen & Salisbury, 1982).…”

Section: The Bay Of Islands Ophiolitementioning

confidence: 99%

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Constraints on Early Paleozoic Deep‐Ocean Oxygen Concentrations From the Iron Geochemistry of the Bay of Islands Ophiolite

Stolper

Lloyd

et al. 2022

Geochem Geophys Geosyst

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The deep ocean is generally considered to have changed from anoxic in the Precambrian to oxygenated by the Late Paleozoic (∼420–400 Ma) due to changes in atmospheric oxygen concentrations. When the transition occurred, that is, in the Early Paleozoic or not until the Late Paleozoic, is less well constrained. To address this, we measured Fe3+/ΣFe of volcanic rocks, sheeted dykes, gabbros, and ultramafic rocks from the Early Paleozoic (∼485 Ma) Bay of Islands (BOI) ophiolite as a proxy for hydrothermal alteration in the presence or absence of O2 derived from deep marine fluids. Combining this data with previously published data from the BOI indicates that volcanic rocks are oxidized relative to intrusive crustal rocks (0.35 ± 0.02 vs. 0.19 ± 0.01, 1 standard error), which we interpret to indicate that the volcanic section was altered by marine‐derived fluids that contained some dissolved O2. We compare our results directly to the Macquarie Island and Troodos ophiolites, drilled oceanic crust, previously compiled data for ophiolitic volcanic rocks, and newly compiled data for ophiolitic intrusive rocks. These comparisons show that the BOI volcanic (but not intrusive) rocks are oxidized relative to Precambrian equivalents, but are less oxidized relative to Late Paleozoic to modern equivalents. We interpret these results to indicate that the Early Paleozoic ocean contained dissolved O2, but at concentrations ∼2.4× lower than for the Late Paleozoic to today.

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Section: The Bay Of Islands Ophiolitementioning

confidence: 96%

Section: The Bay Of Islands Ophiolitementioning

confidence: 99%

Constraints on Early Paleozoic Deep‐Ocean Oxygen Concentrations From the Iron Geochemistry of the Bay of Islands Ophiolite

Stolper

Lloyd

et al. 2022

Geochem Geophys Geosyst

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“…This margin was tectonically overthrust in a westerly direction by the Humber Arm Allochthon in response to ocean closure during the Taconic orogeny. The allochthon incorporates a series of nappes that includes the Cow Head Group, together with the Bay of Islands Ophiolite (Cawood and Suhr, 1992) and Little Port complexes (Williams, 1973; Jenner et al, 1991), from which numerous other Ordovician radiolarian assemblages have been described.…”

Section: Geologic Settingmentioning

confidence: 99%

Middle Ordovician (middle Darriwilian) Archaeospicularia and Entactinaria (radiolarians) from the Table Cove Formation, Piccadilly Quarry, Newfoundland, Canada

Kachovich

Aitchison

2021

J. Paleontol.

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New, distinctive, well-preserved and previously undescribed constituents of a Middle Ordovician (middle Darriwilian, Dw2) radiolarian assemblage from the Table Cove Formation in Newfoundland are described. Three-dimensional X-ray micro-computed tomography (μ-CT) facilitates detailed examination of key specimens revealing hitherto unknown details of the internal morphologies of key lower Paleozoic taxonomic groups, among which a lack of knowledge has previously impeded resolution of higher taxonomic rankings. Twenty-seven archaeospiculid and entactinarian taxa are described and illustrated including six new species: Westernbrookia polygonata n. sp., Neopalaeospiculum piccadilliensis n. sp., Ramuspiculum laxum n. sp. Spongentactinia nazarovi n. sp., Aspiculum irregulare n. sp., and Nyfrieslandia ramosissima n. sp. The investigation extends the known ranges of the species: Pararcheoentactinia reedae Won and Iams, 2002; Sphaeroentactinia robusta Won and Iams, 2015; Varispiculum ectospiculatum Won and Iams, 2015; and Svalbardospiculum multifurcatum (Won, Iams, and Reed, 2005), together with the genus Echidnina to the mid-Darriwilian. UUID: http://zoobank.org/74826b7b-bb86-45d5-ad23-e6e65e0706df.

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