Framboidal pyrite; early-diagenetic, late-diagenetic, and hydrothermal occurrences from the Acton Vale quarry, Cambro-Ordovician, Quebec

Sassano, G. P.; Schrijver, K.

doi:10.2475/ajs.289.2.167

Cited by 25 publications

(9 citation statements)

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“…The presence of pyrite (FeS ) has been observed in Appalachian metasediments (Sassano and Schrijver, 1989; and in the NSF-R7 drilled well of this study) and in the Utica and Lorraine shales (Bérubé et al, 1986), confirming the formation of Fe sulfides in the region during the Paleozoic. Mn nodules from the Ordovician were found in the Appalachians, close to the study area, in the St. Daniel Fm.…”

Section: Origin and Evolution Of Trace Elements In Rocks And Their Resupporting

confidence: 73%

Linking groundwater quality to residence times and regional geology in the St. Lawrence Lowlands, southern Quebec, Canada

Saby

Larocque

Pinti

et al. 2016

Applied Geochemistry

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The assessment of groundwater quality in shallow aquifers is of high societal relevance given that large populations depend directly on these water resources. The purpose of this study was to establish links between groundwater quality, groundwater residence times, and regional geology in the St. Lawrence Lowlands fractured bedrock aquifer. The study focuses on a 4500 km 2 watershed located in the St. Lawrence Lowlands of the province of Quebec in eastern Canada. A total of 150 wells were sampled for major, minor, and trace ions. Tritium (3 H) and its daughter element, 3 He, as well as radiocarbon activity (A 14 C) were measured in a subset of wells to estimate groundwater residence times. Results show that groundwater evolves from a Ca-HCO 3 water type in recharge zones (i.e., the Appalachian piedmont) to a Na-HCO 3 water type downgradient, toward the St. Lawrence River. Locally, barium (Ba), fluoride (F), iron (Fe), and manganese (Mn) concentrations reach 90, 2, 18, and 5.9 mg/L respectively, all exceeding their respective Canadian drinking water limits of 1, 1.5, 0.3, and 0.05 mg/L. Release of these elements into groundwater is mainly controlled by the groundwater redox state and pH conditions, as well as by the geology and the duration of rock-water interactions. This evolution is accompanied by increasing 3 H/ 3 He ages, from 4.78±0.44 years upgradient to more than 60 years downgradient. Discrepancies between calculated 3 H/ 3 He and 14 C water ages (the latter ranging from 280 ± 56 to 17,050 ± 3410 years) suggest mixing between modern water and paleogroundwater infiltrated through subglacial recharge when the Laurentide Ice Sheet covered the study area, and during the following deglaciation period. A linear relationship between 3 H activity and corrected 14 C versus Mg/Ca and Ba support a direct link between water residence time and the chemical evolution of these waters. The Ba, F, Fe, and Mn concentrations in

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Section: Origin and Evolution Of Trace Elements In Rocks And Their Resupporting

confidence: 73%

Linking groundwater quality to residence times and regional geology in the St. Lawrence Lowlands, southern Quebec, Canada

Saby

Larocque

Pinti

et al. 2016

Applied Geochemistry

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“…Occasional framboids are present scattered within the calcite spar and thus post-date it. These may be products of this initial stage of pyrite formation, although framboids may be products of several phases of diagenesis (Sassano & Schrijver, 1989).…”

Section: B Case 2: Mudstone Rich In Organic Carbonmentioning

confidence: 99%

Diagenetic controls on multiphase pyritization of graptolites

Underwood

Bottrell

1994

Geol. Mag.

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Observations on pyritized graptolites have revealed a variety of pyrite morphotypes, several of which often coexist within the same fossil steinkern. The commonest forms of pyrite are those consisting of size-sorted microcrysts, which show degrees of ordering ranging from well-ordered framboids to a more homogeneous, unordered groundmass. Larger, euhedral pyrite crystals may be scattered throughout the microcrystalline groundmass, or be the dominant pyrite form in themselves. ' Floriform' pyrite frequently overgrows earlier framboids and may act to mould the inner periderm microstructure of the graptolite. Overpyrite occurs either as a primary 'overspill' of internal pyrite, or as a separate, later phase.All of the diagenetic pyrite has light sulphur isotope compositions, indicating formation during early diagenesis; isotopic evidence of the relative timing of pyrite generations matches the morphological paragenesis. Under most conditions, available iron appears not to be a limiting factor in pyrite formation, with reactive organic matter only being limiting at the lowest concentrations encountered in these sediments. The availability of organic matter does, however, exert a control on the timing of fossil pyritization. At one locality, a change in diagenetic conditions has allowed for the formation of a morphologically late generation of pyrite with isotopically light and therefore apparently early diagenetic signatures.

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“…Later, scientists found that pyrite framboids pervasively exists in modern marine sediments, freshwater sediments, lacustrine sediments, salt marshes, coal beds, carbonate rocks, moraine sediments, etc. (Stene, 1979;Luther et al, 1982;Weise and Fyfe, 1986;Sassano and Schrijver, 1989;Marnette et al, 1993). It has been suggested that the origin of pyrite framboids is mediated by sulfate reducing bacteria (SRB) activity (Schneiderh€ ohn, 1923;Love, 1957).…”

Section: Pyritementioning

confidence: 98%

Petrologic characteristics and genesis of dolostone from the Campanian of the SK-I Well Core in the Songliao Basin, China

Gao

Wang

et al. 2012

Geoscience Frontiers

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The well SK-I in the Songliao Basin is the first scientific borehole targeting the continental Cretaceous strata in China. Oval concretions, thin laminae and beds of dolostone are found intercalated within mudstone and organic-rich black shale in the Nenjiang Formation of Campanian age. Low ordered ferruginous dolomite is composed of euhedralesubhedral rhombs with cloudy nucleus and light rims formed during the diagenesis, which are typical features of replacement. The heavy carbon isotopes (d 13 C PDB e 1.16e16.0) are results of both the fermentation of organic matter by microbes and degassing of carbon dioxide during the period of diagenesis, and the presence of light oxygen isotopes (d 18 O PDB e 18.53wÀ5.1) is a characteristic feature of fresh water influence which means the carbonate may have been altered by ground water or rainwater in the late diagenesis. Marine water incursions into the normally lacustrine basin have been proved by both the salinity of Z value and the occurrence of foraminifera in the same strata where dolomite occurs. Pyrite framboids observed by SEM are usually enclosed in the dolomite crystals or in the mudstones, supporting the sulfate reducing bacteria (SRB). The formation of both dolomite and pyrite are associated with marine water incursions, which not only supply magnesium GEOSCIENCE FRONTIERS journal homepage: www.elsevier.com/locate/gsf GEOSCIENCE FRONTIERS 3(5) (2012) 669e680 ion for dolomite, but also result in limited carbonate precipitation in the basin. The presence of pyrite framboids indicates the development of an anoxic environment associated with salinity stratification in the lake. The dolomite in the Nenjiang Formation is the results of marine water incursions, diagenetic replacement of calcareous carbonate and sulfate reducing bacteria (SRB). ª 2011, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. All rights reserved.

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Framboidal pyrite; early-diagenetic, late-diagenetic, and hydrothermal occurrences from the Acton Vale quarry, Cambro-Ordovician, Quebec

Cited by 25 publications

References 0 publications

Linking groundwater quality to residence times and regional geology in the St. Lawrence Lowlands, southern Quebec, Canada

Linking groundwater quality to residence times and regional geology in the St. Lawrence Lowlands, southern Quebec, Canada

Diagenetic controls on multiphase pyritization of graptolites

Petrologic characteristics and genesis of dolostone from the Campanian of the SK-I Well Core in the Songliao Basin, China

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