Trilobite biofacies of the Cambrian-Ordovician boundary interval in northern North America

Ludvigsen, Rolf; Westrop, Stephen R.

doi:10.1080/03115518308619614

Cited by 66 publications

(62 citation statements)

References 21 publications

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“…The sequence of changes between the P. glaber and C. albertensis faunas indicates that the Bison Creek-Mistaya grand cycle was terrninated by a relative sea-level rise, which may be a manifestation of the global early Tremadocian onlap (Ludvigsen et al 1988). The reef complex at the top of the Mistaya Formation was drowned (see also Rubin 1980) with the appearance of facies association 2, and deepening continued as facies association 1 spread over the study region; the pattern of trilobite biofacies replacement through this interval is also consistent with a relative sea-level rise (Ludvigsen and Westrop 1983;Westrop 1986).…”

Section: Depositional Historysupporting

confidence: 51%

“…The lower Paleozoic succession forms part of a thick, northeasterly thinning miogeoclinal wedge that probably developed on a subsiding passive margin (Aitken 1981 brim (Marjuman to Sunwaptan Stages; Ludvigsen and Westrop 1985) sequence comprises four complete grand cycles: in ascending order, the Pika, Arctomys and Waterfowl, Sullivan and Lyell, and Bison Creek and Mistaya formations (Fig. 3) (Aitken 1966;Ludvigsen and Westrop 1985, Fig.…”

Section: Stratigraphic Settingmentioning

confidence: 98%

“…Bioclastic packstones, grainstones, and rudstones within these buildups often contain abundant, unabraded trilobites that form a distinct, high-diversity biofacies (Ludvigsen and Westrop 1983;Westrop 1986). The abundance of trilobites supports a shallow subtidal, rather than intertidal, origin for the buildups.…”

Section: Facies Associationmentioning

confidence: 99%

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Facies anatomy of an Upper Cambrian grand cycle: Bison Creek and Mistaya formations, southern Alberta

Westrop¹

1989

Can. J. Earth Sci.

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The Bison Creek and Mistaya formations form the youngest Cambrian sedimentary grand cycle exposed in Banff and Jasper national parks. The shaly half-cycle of the Bison Creek Formation records the displacement of a carbonate bank during a major rise in sea level that can be identified in other parts of North America. Lithofacies of the Bison Creek Formation fall into three recurrent associations that represent sedimentation in shallow, subtidal, storm-dominated shelf settings. The Mistaya Formation records the reestablishment of carbonate bank deposition, probably due to a decrease in the rate of sea-level rise, and includes two facies associations that represent a mosaic of shallow subtidal to supratidal environments. The grand cycle was terminated by a sea-level rise, possibly eustatic in nature, that drowned the carbonate platform. The overlying shales, mudstones, packstones, grainstones, and rudstones of the Survey Peak Formation mark a return to subtidal, storm-dominated shelf conditions.

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Section: Depositional Historysupporting

confidence: 51%

Section: Stratigraphic Settingmentioning

confidence: 98%

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Facies anatomy of an Upper Cambrian grand cycle: Bison Creek and Mistaya formations, southern Alberta

Westrop¹

1989

Can. J. Earth Sci.

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“…This interval is characterized by rapid speciation within genera assigned to numerous families that are well represented in platform faunas. Eurekiid, dikelocephalid, and ptychaspidid genera (amongst others) display rapid turnover of species through this interval in high-energy, grainstone-rich platform facies (the Euptychaspis-Eurekia Biofacies of Ludvigsen & Westrop 1983). Plethopeltid and catillicephalid species are similarly short-ranging in microbial-reef-dominated facies through the upper Jiangshanian Stage and lower part of the proposed Lawsonian Stage.…”

Section: Trilobitesmentioning

confidence: 97%

Proposed stratotype for the base of the Lawsonian Stage (Cambrian Stage 10) at the First Appearance Datum of Eoconodontus notchpeakensis (Miller) in the House Range, Utah, USA

Miller¹,

Evans²,

Freeman³

et al. 2011

Bull. Geosci.

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The name Lawsonian Stage is proposed as the highest stage of the Cambrian System (Stage 10). The base of the proposed Lawsonian Stage is at the First Appearance Datum (FAD) of the euconodont Eoconodontus notchpeakensis (Miller, 1969). That horizon, the base of the E. notchpeakensis Subzone of the Eoconodontus Zone, is 3mabove the base of the Red Tops Member of the Notch Peak Formation at the Steamboat Pass section in the House Range, western Utah, USA. The conodont fauna of the Eoconodontus Zone is widespread in North America and occurs in Asia, Australia, Europe, and South America in facies that include cratonic nearshore sandstones, shallow and intermediate-depth platform carbonates, deep-water ramp, continental slope deposits, and deep-ocean radiolarian chert. This horizon lies at or slightly below the top of the Illaenurus trilobite Zone of western North America and within the lower part of the Saukiella junia Subzone of the Saukia Zone in areas east of the Rocky Mountains. These trilobite and conodont faunas can be traced into slope deposits containing cosmopolitan trilobites. The horizon is nearly coincident with the boundary between the Billingsella and the Finkelnburgia calcitic brachiopod Zones; ranges of organophosphatic brachiopods also characterize the horizon. A high-amplitude, negative, carbon-isotope excursion, the HERB Event, occurs in the Eoconodontus notchpeakensis Subzone. This distinctive geochemical signal is known in western Utah, Australia, China, and in poorly fossiliferous slope deposits in Newfoundland, Canada. The proposed boundary fits between two closely spaced sequence-stratigraphic boundaries described from Utah and Texas, USA

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“…As noted by Ludvigsen and Westrop (1983), binary data tends to overemphasize rare taxa and can hamper discrimination of taxa associations. Moreover, rare species may be difficult to interpret due to poor representation in the rock record (Brower 1987;Soja 1988;Brower and Nye 1991).…”

Section: Methodsmentioning

confidence: 97%

Llandovery (Early Silurian) orthide brachiopod associations from Anticosti Island, eastern CanadaThis article is one of a series of papers published in this Special Issue on the theme The dynamic reef and shelly communities of the Paleozoic. This Special is in honour of our colleague and friend Paul Copper.

Allen²

2008

Can. J. Earth Sci.

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Five Llandovery orthide brachiopod associations, through cluster analysis, are delineated on Anticosti Island. The Levenea-Dicoelosia Association (A), occurring in the Goéland and Richardson members of the lower Jupiter Formation, represents a deep-water setting around or below the maximum storm wave base. The Flabellitesia-Dalejina Association (B), appearing in the Cybèle, Ferrum, and Pavillon members of the upper Jupiter Formation, indicates water depth in between the maximum and normal storm wave bases. The Isorthis (Ovalella) Association (C1), present in the Fox Point Member of Becscie Formation, corresponds to the shallower water setting around the normal storm wave base. The Mendacella bleikeriensis Association (C2), occurring in the Innommée, Sandtop, and Macgilvray members of Gun River Formation, characterizes the water depth slightly below the normal storm wave base. The Mendacella udauberis Association (D), appearing in the Merrimack Formation, signifies a water depth around the maximum storm wave base. The water depth indication of these associations may bear potential as future reference for other regions, but attention should be paid to the species level as some congeneric species can belong to different associations of different depth. The cluster analysis on orthide collections based on binary data demonstrates that statistical methods, Jaccard coefficient and Ward's method of clustering, are practical and effective to delineate large brachiopod collections on Anticosti Island.

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Trilobite biofacies of the Cambrian-Ordovician boundary interval in northern North America

Cited by 66 publications

References 21 publications

Facies anatomy of an Upper Cambrian grand cycle: Bison Creek and Mistaya formations, southern Alberta

Facies anatomy of an Upper Cambrian grand cycle: Bison Creek and Mistaya formations, southern Alberta

Proposed stratotype for the base of the Lawsonian Stage (Cambrian Stage 10) at the First Appearance Datum of Eoconodontus notchpeakensis (Miller) in the House Range, Utah, USA

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