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Dunn Point Formation

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Journal Article
Published: 21 December 2011
Geological Magazine (2012) 149 (5): 798–818.
...P. JUTRAS; J. J. HANLEY; R. S. QUILLAN; M. J. LEFORTE Abstract Mafic flows of the Middle to Upper Ordovician Dunn Point Formation of eastern Canada were deeply weathered under warm and relatively humid conditions before being buried by subsequent flows. In the absence of superior plants...
Journal Article
Published: 27 May 2014
Geological Magazine (2015) 152 (1): 143–165.
... of intra-basaltic palaeosols of the Dunn Point Formation in eastern Canada ( Fig. 1 a) (Boucot et al. 1974 ; Feakes, Holland & Zbinden, 1989 ; Jutras, Quillan & LeForte, 2009 ; Jutras et al. 2012 ), which is part of a volcanic succession that hosts the youngest known palaeosols...
FIGURES
First thumbnail for: Record of climatic fluctuations and high pH weathe...
Second thumbnail for: Record of climatic fluctuations and high pH weathe...
Third thumbnail for: Record of climatic fluctuations and high pH weathe...
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The Dunn Point Formation volcanics and associated weathering profiles in Arisaig, Nova Scotia, eastern Canada. A: General map. P.E.I.—Prince Edward Island. B: Weathering profile in rhyolite, rotated to the horizontal (meter stick for scale). C: Truncation of calcite veins by weathering (pen [~10 cm] for scale). D: Weathering profile in basalt paleosol 3 (meter stick for scale).
Published: 01 January 2009
Figure 1. The Dunn Point Formation volcanics and associated weathering profiles in Arisaig, Nova Scotia, eastern Canada. A: General map. P.E.I.—Prince Edward Island. B: Weathering profile in rhyolite, rotated to the horizontal (meter stick for scale). C: Truncation of calcite veins by weathering
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Mineralogical and geochemical contents in the Dunn Point Formation paleosols and host rocks from X-ray diffraction (vol%) and X-ray fluorescence (wt% for major oxides, and ppm for trace elements) data, respectively. Basalt paleosol 1 is used as a representative of the basalt paleosols, which all show very similar variations (Tables DR1 and DR3 [see text footnote 1]).
Published: 01 January 2009
Figure 2. Mineralogical and geochemical contents in the Dunn Point Formation paleosols and host rocks from X-ray diffraction (vol%) and X-ray fluorescence (wt% for major oxides, and ppm for trace elements) data, respectively. Basalt paleosol 1 is used as a representative of the basalt paleosols
... The Early Silurian–Early Devonian Arisaig Group, in the Avalon terrane of Nova Scotia, consists of a thick (∼1900 m) sequence of unmetamorphosed fossiliferous siliciclastic strata that unconformably overlies the 460 Ma bimodal Dunn Point Formation volcanic rocks and is unconformably overlain...
Journal Article
Journal: Lithosphere
Publisher: GSW
Published: 14 September 2020
Lithosphere (2020) 2020 (1): 8837633.
... paleocontinental reconstructions that consistently show Avalonia as a drifting microcontinent during that period. Identification of volcanic rocks with an intermediate composition (the new Seaspray Cove Formation) between upper Darriwilian bimodal volcanic rocks of the Dunn Point Formation and Sandbian felsic...
FIGURES
First thumbnail for: Evolution of Subduction Dynamics beneath West Aval...
Second thumbnail for: Evolution of Subduction Dynamics beneath West Aval...
Third thumbnail for: Evolution of Subduction Dynamics beneath West Aval...
Series: GSA Special Papers
Published: 01 January 1974
DOI: 10.1130/SPE139-p89
... Browns Mountain Group are not established. BEARS BROOK VOLCANIC GROUP Dunn Point Formation The Bears Brook Volcanic Group was formed under predominantly terrestrial conditions, probably during the Upper Ordovician. Subaerial conditions are proved by the complete lateritic soil profiles...
Journal Article
Published: 19 December 2011
Canadian Journal of Earth Sciences (2012) 49 (1): 346–358.
... in the Dunn Point Formation (DPF) yielded an age of 460.0 ± 3.4 Ma, and, here, we report a concordant age of 454.5 ± 0.7 Ma for an ignimbrite in the overlying McGillivray Brook Formation (MBF). These data confirm a ca. 10 million year gap between volcanism and onset of Arisaig Group deposition, which occurred...
Journal Article
Published: 01 May 1984
The Canadian Mineralogist (1984) 22 (2): 269–280.
... to positive chlorite was induced by deformation during and after lower-greenschist-facies metamorphism. Interlayered and intermixed positive and negative chlorites in the matrix of undeformed metavolcanic rocks of the Dunn Point Formation, Nova Scotia, are cross-cut by veins of positive chlorite. Negative...
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Figure 1. Summary geological map of Antigonish Highlands (from Murphy et al., 1991). Age dates quoted are U-Pb (zircon, thermal ionization mass spectrometry). A is Avalonia (dark shade). Reconstructions for 600 Ma, 540 Ma, 460 Ma, and 370 Ma (modified after Stampfli and Borel, 2002) show paleogeographic locations of Clydesdale, Arbuckle, Bears Brook–Dunn Point, and McArras Brook Formations, respectively. SCLM— subcontinental lithospheric mantle; CF—Clydesdale Formation; AB—Arbuckle Brook Formation; DP— Dunn Point Formation; BB—Bears Brook formation; Mc—McArras Brook Formation.
Published: 01 April 2007
paleogeographic locations of Clydesdale, Arbuckle, Bears Brook–Dunn Point, and McArras Brook Formations, respectively. SCLM— subcontinental lithospheric mantle; CF—Clydesdale Formation; AB—Arbuckle Brook Formation; DP— Dunn Point Formation; BB—Bears Brook formation; Mc—McArras Brook Formation.
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Figure 2. FeOt/MgO vs. FeOt (after Miyashiro, 1974) for (A) Clydesdale Formation, (B) Arbuckle Brook Formation, (C) Bears Brook–Dunn Point Formations, and (D) McArras Brook Formation. Sk—Skaergaard trend; TH—tholeiitic; CA—calc-alkalic.
Published: 01 April 2007
Figure 2. FeO t /MgO vs. FeO t (after Miyashiro, 1974 ) for (A) Clydesdale Formation, (B) Arbuckle Brook Formation, (C) Bears Brook–Dunn Point Formations, and (D) McArras Brook Formation. Sk—Skaergaard trend; TH—tholeiitic; CA—calc-alkalic.
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Figure 3. Enriched mid-ocean ridge basalt (E-MORB) normalized spider diagrams. A: Clydesdale Formation. B: Arbuckle Brook Formation. C: Bears Brook–Dunn Point Formations. D: McArras Brook Formation. Normalizing values are from Sun and McDonough (1989). OIB—ocean-island basalt.
Published: 01 April 2007
Figure 3. Enriched mid-ocean ridge basalt (E-MORB) normalized spider diagrams. A: Clydesdale Formation. B: Arbuckle Brook Formation. C: Bears Brook–Dunn Point Formations. D: McArras Brook Formation. Normalizing values are from Sun and McDonough (1989) . OIB—ocean-island basalt.
Image
Weathered and sheared trachyandesite of the Seaspray Cove Formation truncating weathered rhyolite of the Dunn Point Formation, and conformably overlain by tuff of the McGillivray Brook Formation at the Frenchman’s Barn northeast section (locality shown in Figure 1). View towards the southwest. Sample localities are indicated. Modified from Jutras et al. [26].
Published: 14 September 2020
Figure 4 Weathered and sheared trachyandesite of the Seaspray Cove Formation truncating weathered rhyolite of the Dunn Point Formation, and conformably overlain by tuff of the McGillivray Brook Formation at the Frenchman’s Barn northeast section (locality shown in Figure 1 ). View towards
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Figure 1.
Published: 27 May 2014
Figure 1. (a) Simplified geology of the study area (modified from Boucot et al. 1974 ), and section localities. The inset situates the study area within eastern Canada. (b, c) Lateral variations between unweathered rhyolite of the uppermost Dunn Point Formation
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Fig. 12.
Published: 26 February 2013
Fig. 12. Summary diagram for ages (shown as bars including errors) from units of the West Barneys River Plutonic Suite (this study; Escarraga et al. 2012 ), Cape Porcupine Complex (CPC; this study; Barr et al. 2012 ), Dunn Point Formation (DPF; Hamilton and Murphy 2004 ), and McGillivray
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Vertical mass gains and losses in the Middle Ordovician Dunn Point Formation paleosols with respect to that of their host rocks. A: Rhyolite paleosol. B: Basalt paleosol 3. C: Basalt paleosol 2. D: Basalt paleosol 1. Based on the dimensionless element-mass-transfer coefficients of Anderson et al. (2002; modified from Brimhall et al., 1992), assuming Zr immobility.
Published: 01 January 2009
Figure 3. Vertical mass gains and losses in the Middle Ordovician Dunn Point Formation paleosols with respect to that of their host rocks. A: Rhyolite paleosol. B: Basalt paleosol 3. C: Basalt paleosol 2. D: Basalt paleosol 1. Based on the dimensionless element-mass-transfer coefficients
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Field relationships between pyroclastic breccia and lava flow units of the Seaspray Cove Formation and tuff of the McGillivray Brook Formation at the Seaspray Cove locality (shown in Figure 1). Postdeposition faulting concentrated in the weak, weathered upper part of the trachyandesitic lava flow unit, which resulted in local duplications of its more competent base. Sample localities are indicated. DPB: Dunn Point Formation basalt; SCPB: Seaspray Cove Formation pyroclastic breccia; SCLF: Seaspray Cove Formation trachyandesitic lava flow unit; P: paleosol; SP: sheared paleosol and fault breccia; TFS: trachyandesite fault slab; MBT: McGillivray Formation tuff; MBI: McGillivray Formation ignimbrite. The satellite image is from Google Maps.
Published: 14 September 2020
of the trachyandesitic lava flow unit, which resulted in local duplications of its more competent base. Sample localities are indicated. DPB: Dunn Point Formation basalt; SCPB: Seaspray Cove Formation pyroclastic breccia; SCLF: Seaspray Cove Formation trachyandesitic lava flow unit; P: paleosol; SP: sheared paleosol
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Trace element diagrams based on ICP-MS data from Tables 2 and 3 (LA-ICP-MS from Data Repository Files #1 and #2 in the case of the pyroclastic breccia matrix of the Seaspray Cove Formation) and normalized against primitive mantle values from Sun and McDonough [70]. (a) Comparisons between the average enriched midoceanic ridge basalt (E-MORB; based on [41]), the Dunn Point Formation basalts, and the Seaspray Cove Formation trachyandesitic lava flow unit and pyroclastic breccia matrix; (b) comparisons between the Seaspray Cove Formation trachyandesitic flow unit and felsic ignimbrite of the McGillivray Brook Formation. ∗: data from Keppie et al. [12]; ∗∗: data from the least altered samples of ignimbrite analyzed by Murphy et al. [14] based on Na2O (>1%) and LOI (<1%) contents.
Published: 14 September 2020
between the average enriched midoceanic ridge basalt (E-MORB; based on [ 41 ]), the Dunn Point Formation basalts, and the Seaspray Cove Formation trachyandesitic lava flow unit and pyroclastic breccia matrix; (b) comparisons between the Seaspray Cove Formation trachyandesitic flow unit and felsic
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Figure 9.
Published: 27 May 2014
Figure 9. Pedogenic and diagenetic model for the intra-rhyolitic palaeosol of the Middle to Upper Ordovician Dunn Point Formation. (a) Development of a low water-table following the emplacement of thick rhyolite, and beginning of an illitization of pedogenic
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Igneous rock classification of the Dunn Point, Seaspray Cove, and McGillivray Brook Formations based on Zr/Ti and Nb/Y ratios (after [30]). Thoroughly weathered samples (Q10, S3-7, and S3-8) are excluded. N=20 refers to the number of averaged point samples from the microprobe (for Ti) and LA-ICP-MS (for Zr, Nb, and Y).
Published: 14 September 2020
Figure 9 Igneous rock classification of the Dunn Point, Seaspray Cove, and McGillivray Brook Formations based on Zr/Ti and Nb/Y ratios (after [ 30 ]). Thoroughly weathered samples (Q10, S3-7, and S3-8) are excluded. N = 20 refers to the number of averaged point samples from the microprobe