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Twitya Formation

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Journal Article
Published: 01 October 1976
Canadian Journal of Earth Sciences (1976) 13 (10): 1446-1455.
...Peter Laznicka Abstract Conspicuous spherical and subspherical barite nodules occur in Devonian(?)/Mississippian carbonaceous shales and argillaceous dolomitic limestones in Twitya river area (western foothills of the Backbone Ranges, Mackenzie Mountains, N.W.T.).The majority of barite nodules...
Journal Article
Journal: GSA Bulletin
Published: 01 October 1994
GSA Bulletin (1994) 106 (10): 1281-1292.
.... The C- and Sr-isotopic abundances of lower Keele Formation carbonates approximate those for other pre-Varanger samples, confirming that the simple disc-like fossils of the underlying Twitya Formation predate all known diverse Ediacaran faunas. "Tepee" and Sheepbed carbonates record strong post-glacial...
Journal Article
Journal: Geology
Published: 01 December 1990
Geology (1990) 18 (12): 1199-1202.
...H. J. Hofmann; G. M. Narbonne; J. D. Aitken Abstract A turbidite sequence within the Twitya Formation (Windermere Supergroup) in the ackenzie Mountains, northwestern Canada, has yielded an assemblage composed of simple centimetric annuli and discs, which are interpreted as biogenic and referred...
Image
Multiproxy sedimentary geochemistry of the <b>Twitya</b> and Ice Brook <b>Formations</b> ...
Published: 01 March 2016
Figure 4. Multiproxy sedimentary geochemistry of the Twitya and Ice Brook Formations at Bluefish Creek. Note that the Ice Brook Formation, which bears the macroscopic discoidal fossils ( Hoffmann et al., 1990 ; Figs. 2E–2G ), is mapped at the appearance of deep-water quartz pebble-conglomerate
Image
(A–D) Ediacaran soft-bodied fossils from Sekwi Brook and (E–G) “<b>Twitya</b> disc...
Published: 01 March 2016
dickinsoniomorph from the uppermost Blueflower Formation; (B) Pterinidinium? , from the lower Blueflower Formation; (C) Primocandelabrum , a deep-water frond attached to a discoid holdfast in the June beds; (D) Fractofusus , a deep-water rangeomorph from the June beds; (E–F) discoidal “Twitya discs”; (G
Journal Article
Journal: GSA Bulletin
Published: 01 March 2016
GSA Bulletin (2016) 128 (3-4): 558-575.
...Figure 4. Multiproxy sedimentary geochemistry of the Twitya and Ice Brook Formations at Bluefish Creek. Note that the Ice Brook Formation, which bears the macroscopic discoidal fossils ( Hoffmann et al., 1990 ; Figs. 2E–2G ), is mapped at the appearance of deep-water quartz pebble-conglomerate...
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Journal Article
Published: 30 January 2012
Canadian Journal of Earth Sciences (2012) 49 (2): 455-476.
... the basal Windermere Supergroup (e.g., Narbonne and Aitken 1995 ; Long et al. 2008 ). Overlying the Rapitan Group in the Redstone River region ( Fig. 1A ) is the Hay Creek Group ( Yeo 1978 ; James et al. 2001 ), the lowermost formation of which is the Twitya Formation, which contains disc-shaped...
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Journal Article
Journal: GSA Bulletin
Published: 01 April 2002
GSA Bulletin (2002) 114 (4): 387-399.
...Grant M. Young Abstract The Mineral Fork Formation is an isolated unit of Neoproterozoic glaciogenic rocks in the Wasatch Range in northwestern Utah. Geochemical analyses of diamictite and mudstone samples were carried out to document its major and trace element geochemistry. Comparison...
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Figure 1. Inset: Location of study area. Left: Stratigraphic column, lower ...
in > Geology
Published: 01 January 2005
Figure 1. Inset: Location of study area. Left: Stratigraphic column, lower part of Windermere Supergroup. Right: Stratigraphic column at 64°40′30″N, 129°54′15″W, upper part of Twitya Formation (Twitya-Keele transition) showing lithologies and location of glendonite pseudomorphs (stars)
Journal Article
Published: 01 September 2000
Journal of Paleontology (2000) 74 (5): 767-788.
...SHUHAI XIAO; ANDREW H. KNOLL Abstract Phosphorites of the uppermost Neoproterozoic Doushantuo Formation (ca. 570 ± 20 Ma) exposed at Weng'an, South China, contain globular microfossils characterized by distinctively sculpted outer coverings and precise patterns of cell division. Forms assigned...
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Journal Article
Published: 01 January 2016
Journal of the Geological Society (2016) 173 (1): 177-185.
... dynamically affect porewater conditions, and allow the build-up of overpressure that can drive dewatering and degassing to produce a suite of atypical fluid-escape features. Finely bedded silty and sandy laminae from the c . 560 Ma Burway Formation of the Longmyndian Supergroup, Shropshire, England, reveal...
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Journal Article
Published: 20 August 2004
Canadian Journal of Earth Sciences (2004) 41 (9): 1013-1025.
... (Sayunei and Shezal formations), followed by the interglacial Twitya Formation and the younger tillites of the Ice Brook and Keele formations. The younger tillite is overlain in turn by deep-water shale of the Sheepbed Formation, deep-water carbonates (Gametrail Formation), deep-water shale (Blueflower...
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Journal Article
Journal: GSA Bulletin
Published: 08 March 2019
GSA Bulletin (2019) 131 (9-10): 1673-1701.
... ). The Cryogenian Hay Creek Group includes the Twitya, Keele, and Ice Brook formations ( Fig. 2 ), the Mount Profeit dolostone and the informal “Tepee dolostone” or Ravensthroat formation ( Gabrielse et al., 1973 ; Eisbacher, 1978 , 1981 ; Yeo, 1978 ; Aitken, 1991a ; James et al., 2001 ; Turner et al., 2011...
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Journal Article
Journal: GeoArabia
Publisher: Gulf Petrolink
Published: 01 October 2008
GeoArabia (2008) 13 (4): 45-72.
... continuous succession of little-deformed sedimentary rocks containing two glacial intervals separated by c. 1 km of non-glacial marine deposits. The lowermost glacial interval (Ayn Formation) occupies deep paleovalleys incised into crystalline basement. The overlying Arkahawl Formation records at its base...
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Journal Article
Journal: GSA Bulletin
Published: 01 March 2003
GSA Bulletin (2003) 115 (3): 349-372.
...) seems to be more in line with our new geochronologic information. In Canada, work has suggested that the “grits” of the lower parts of the Horsethief Creek, Kaza, Misinchinka, and Miette Groups are partly equivalent with the Monk Formation to the south and with the Twitya Formation of the Rapitan...
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Journal Article
Published: 05 July 2000
Canadian Journal of Earth Sciences (2000) 37 (7): 997-1020.
... ). The rift-drift transition is generally placed at the base of the Twitya Formation ( Narbonne and Aitken 1995 ). The uppermost three formations in the Windermere Supergroup (Fig.  2 )—the Gametrail, Blueflower, and Risky formations ( Aitken 1989 )—are all superbly exposed in the Sekwi Brook region...
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Series: Geological Society, London, Memoirs
Published: 01 January 2011
DOI: 10.1144/M36.36
EISBN: 9781862394117
.... It includes the Sayunei, Shezal and Twitya formations (Fig.  36.2 ). Eisbacher (1978) enlarged the Rapitan Group to include the Keele Fm. because of its gradational relationship with the Twitya Fm. However, Yeo (1981) and most subsequent workers follow the original definition ( Green & Godwin 1963...
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Figure 16. Schematic representation of the Neoproterozoic stratigraphy of t...
Published: 01 April 2002
.—Mount Berg Formation; Sa.—Sayunei Formation; Sh.—Shezal Formation; I.B.—Ice Brook Formation; Tw.—Twitya Formation; Ke.—Keele Formation; B.C.—British Columbia. Possible correlations (cf. Link et al., 1993 ) are shown by the shaded areas connecting parts of the the columns. Note the Fe-rich intervals
Journal Article
Journal: Economic Geology
Published: 01 November 2017
Economic Geology (2017) 112 (7): 1773-1806.
... continental shelf, slope, and platform strata were deposited throughout the remainder of the Neoproterozoic (e.g., from the Twitya Formation to the Backbone Ranges Formation; Fig. 2 ) in response to the cooling and thickening of the mantle lithosphere ( Ross, 1991 ; Narbonne and Aitken, 1995 ; Turner et al...
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(A) Schematic pore fluid pressure vs. depth curve through the Coates Lake b...
Published: 01 November 2017
stratiform copper mineralization and fluid convection in Coates Lake basin. The transition from localized rift sedimentation to areally extensive basins of the Twitya Formation resulted in the formation of lithological seals over pre-Twitya rift faults. “Cu” marks the formation of stratiform copper