Toward a sequence stratigraphic framework for the Frasnian of the Western Canada Basin

Potma, Ken; Weissenberger, John A.W.; Wong, Pak K.; Gilhooly, Murray G.

doi:10.2113/49.1.37

Cited by 51 publications

(80 citation statements)

References 73 publications

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“…1c). The formation formed in shallow subtidal to supratidal environments during the Late Devonian (Thériault and Hutcheon, 1987;Machel et al, 2012), as a prograding carbonate ramp and/or a carbonate shelf formed on an intracratonic basin during regression (Cutler, 1983;Potma et al, 2001). The Grosmont Formation was subaerially exposed and formed karst features from the Late Jurassic to Early Cretaceous (Thériault and Hutcheon, 1987;Machel et al, 2012).…”

Section: Geological Settingmentioning

confidence: 99%

Geochemical characterization of an organic-rich carbonate from the Grosmont Formation, Alberta, Canada

et al. 2015

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The Grosmont Formation is a massive, organic-rich carbonate deposit that subdivides into upper (UG) and lower (LG) units. Geochemical analyses of Grosmont carbonate rocks collected from wells 10-12-93-24W4 and 11-33-94-22W4 allowed us to differentiate the depositional and diagenetic conditions for these two units. The UG unit subdivides into three subunits (UG1-UG3) and consists of fine-to coarse-crystalline and subhedral dolomite. The LG unit consists of dolomitic limestone and calcareous dolostone with medium-to coarse-crystalline, euhedral to subhedral dolomite and calcite. These units also include small amounts of quartz, illite, pyrite, K-feldspar and other trace minerals. Petrographic and geochemical analyses indicate that the LG unit formed under influence of clastic sediment input. Isotopic ratios for UG dolomites suggest precipitation within a near surface environment under evaporitic/hypersaline conditions. By contrast, the LG dolomite may have formed in a diagenetic environment at salinities lower than those inferred for UG samples, according to observed isotopic ratios. Both UG and LG carbonates exhibit 87 Sr/ 86 Sr ratios (0.7082 to 0.7086) and δ 18 O values (-4.03 to -6.09‰ PDB) that are consistent with formation from Devonian seawater at temperatures ranging from 44°C to 57°C.

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Section: Geological Settingmentioning

confidence: 99%

Geochemical characterization of an organic-rich carbonate from the Grosmont Formation, Alberta, Canada

et al. 2015

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“…3B). A system of attached and detached platforms, with a distinct NE-SW trend developed in the Frasnian (Potma et al, 2001) (Fig. 4).…”

Section: Geological Setting Of the Frasnian In Albertamentioning

confidence: 99%

“…4). Sequence stratigraphic frameworks are proposed by van Buchem et al (1996), Whalen et al (2000a), and Potma et al (2001).…”

Section: Geological Setting Of the Frasnian In Albertamentioning

confidence: 99%

Magnetic susceptibility evolution and sedimentary environments on carbonate platform sediments and atolls, comparison of the Frasnian from Belgium and Alberta, Canada

Silva

Potma

Weissenberger³

et al. 2009

Sedimentary Geology

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a b s t r a c t a r t i c l e i n f oKeywords: Frasnian Magnetic susceptibility Correlations Platforms and atolls Magnetic susceptibility (MS) measurements on carbonate rocks are considered as a proxy for impurities delivered to the carbonate environments. In the absence of strong climatic or tectonic variations, bulk MS values have been linked to sea level variations, because sea-level fall increases clastic supply and therefore increases in magnetic mineral deposition. In this paper we explore the relationship between the average magnitude of bulk MS, with shallowing-up sequences and facies evolution in different Devonian carbonate complexes. Similarities and differences between these parameters have been scrutinized in carbonate attached platform and detached platforms (mounds and/or atolls) from Belgium and Canada. In the carbonate attached platforms from Belgium and Canada, the MS patterns are directly related to depositional environment. Mean MS values increase from the most distal towards the most proximal facies and towards the top of the majority of fourth-order shallowing-up sequences. These trends are in agreement with theoretical background (MS increases with regression). In the Belgian detached platform, the average MS pattern generally shows an opposite behaviour to that observed in the attached carbonate platforms. Average MS decreases towards the most proximal facies and towards the top of a majority of the fourth-order shallowing-up sequences. This behaviour can be explained by the influence of sedimentary rate and water agitation during deposition. A high sedimentary rate will dilute the magnetic minerals in the atoll facies and the high water agitation during deposition may be expected to have prevented the deposition of the magnetic grains. So, the combination of these two effects will result in the observed low values in the atoll crown and lagoonal facies. In the Canadian detached platform, MS is mainly negative. This means that the limestones are very pure. The technique does not appear to be appropriate in these rocks. The variations of average MS behaviour by platform type can imply difficulties in correlating carbonates from different settings. A comparison of time equivalent mound and platform deposits shows that after an important regressive surface, the MS values are increasing for the platform deposits and decreasing for the mound. So MS evolution can be in complete opposition (caused by highly different sedimentary rates) in different depositional settings. The MS signal preserved in carbonate rocks is probably mainly related to 1) varying clastic supplies; 2) varying carbonate accumulation rates (dilution of the magnetic minerals by high carbonate production) and 3) potentially diagenesis.

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“…Wong, and M.G. Gilhooly (Potma et al, 2001) propose that brine reflux must have formed almost all of these dolomites in the Alberta Basin. Rather than using multiple lines of evidence, they base their model of brine reflux dolomitization (with a salinity of at least gypsum saturation, i.e.…”

Section: The Problem At Hand -Pervasive Replacive Dolomitization In Tmentioning

confidence: 99%

“…It is important to work cautiously and critically, to gather as many lines of evidence as possible, to consider all the available evidence in the final analysis, and to present well supported conclusions. Unfortunately, Potma et al (2001) did not follow these guidelines.…”

Section: Introductionmentioning

confidence: 99%