Sedimentological and geochemical basin analysis of the Paleoproterozoic Penrhyn and Piling groups of Arctic Canada

Partin, Camille A.; Bekker, Andrey; Corrigan, D; Modeland, S.; Francis, D.; Davis, Donald W.

doi:10.1016/j.precamres.2014.06.010

Cited by 30 publications

(31 citation statements)

References 67 publications

(47 reference statements)

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“…To build a more continuous iron speciation record through Proterozoic time, some studies have started to analyze rocks that have been metamorphosed to greenschist facies or above. Asael et al (2013) and Partin et al (2015) both worked on ~2.0 to 1.9 Ga greenschist facies rocks (with the latter study extending to lower amphibolite facies) that contained prevalent pyrrhotite interpreted to form metamorphically from pyrite (Melezhik et al, 2015;Partin et al, 2014). As discussed above, through the use of petrography and iron speciation extractions, the metamorphic reactions were respectively attributed to open system fluid desulfurization reactions and closed system iron oxide sulfurization from neighboring pyrite.…”

Section: Discussionmentioning

confidence: 99%

The effects of metamorphism on iron mineralogy and the iron speciation redox proxy

Slotznick

Eiler

Fischer

2018

Geochimica et Cosmochimica Acta

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As the most abundant transition metal in the Earth's crust, iron is a key player in the planetary redox budget. Observations of iron minerals in the sedimentary record have been used to describe surface atmospheric and aqueous redox environments over the evolution of our planet; the most common method applied is iron speciation, a geochemical sequential extraction method in which proportions of different iron minerals are compared to calibrations from modern sediments to determine water-column redox state. Less is known about how this proxy records information through post-depositional processes, including diagenesis and metamorphism. To get insight into this, we examined how the iron mineral groups/pools (silicates, oxides, sulfides, etc.) and paleoredox proxy interpretations can be affected by known metamorphic processes. Well known metamorphic reactions occurring in sub-chlorite to kyanite rocks are able to move iron between different iron pools along a range of proxy vectors, potentially affecting paleoredox results. To quantify the effect strength of these reactions, we examined mineralogical and geochemical data from two classic localities where SilurianDevonian shales, sandstones, and carbonates deposited in a marine sedimentary basin with oxygenated seawater (based on global and local biological constraints) have been regionally metamorphosed from lower-greenschist facies to granulite facies: Waits River and Gile Mountain Formations, Vermont, USA and the Waterville and Sangerville-Vassalboro Formations, Maine, USA. Plotting iron speciation ratios determined for samples from these 2 localities revealed apparent paleoredox conditions of the depositional water column spanning the entire range from oxic to ferruginous (anoxic) to euxinic (anoxic and sulfidic). Pyrrhotite formation in samples highlighted problems within the proxy as iron pool assignment required assumptions about metamorphic reactions and pyrrhotite's identification depended on the extraction techniques utilized. The presence of diagenetic iron carbonates in many samples severely affected the proxy even at low grade, engendering an interpretation of ferruginous conditions in all lithologies, but particularly in carbonate-bearing rocks. Increasing metamorphic grades transformed iron in carbonates into iron in silicate minerals, which when combined with a slight increase in the amount of pyrrhotite, drove the proxy toward more oxic and more euxinic conditions. Broad-classes of metamorphic reactions (e.g. decarbonation, silicate formation) occurred at distinct temperatures-pressures in carbonates versus siliciclastics, and could be either abrupt between metamorphic facies or more gradual in nature. Notably, these analyses highlighted the importance of trace iron in phases like calcite, which otherwise might not be included in iron-focused research i.e. ore-system petrogenesis, metamorphic evolution, or normative calculations of mineral abundance. The observations show that iron is mobile and reactive during diagenesis and metamorphism, a...

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Section: Discussionmentioning

confidence: 99%

The effects of metamorphism on iron mineralogy and the iron speciation redox proxy

Slotznick

Eiler

Fischer

2018

Geochimica et Cosmochimica Acta

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“…Observations within the better-preserved northern Longstaff Bluff formation, including the generally fi ne-grained nature of the turbiditic rocks, the dominance of normal-graded bedding, and the lateral continuity in bedding thicknesses, combine to suggest that the bedded strata represent distal-facies turbidite (e.g., Henderson and Tippett, 1980) deposited on the suprafan lobe portion of an outer submarine fan (Tippett, 1984a). Most authors suggest that the deep-water deposits signal a dramatic change in tectonic conditions, with accumulation in a foreland, molasse-type or back-arc basin (e.g., Jackson, 2000;Corrigan et al, 2001;Scott et al, 2003;St-Onge et al, 2005;Partin et al, 2014b).…”

Section: Stratigraphy Of the Piling Groupmentioning

confidence: 99%

Did a proto-ocean basin form along the southeastern Rae cratonic margin? Evidence from U-Pb geochronology, geochemistry (Sm-Nd and whole-rock), and stratigraphy of the Paleoproterozoic Piling Group, northern Canada

Wodicka

St-Onge

Corrigan

et al. 2014

Geological Society of America Bulletin

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The Paleoproterozoic Piling Group along the southeastern Rae margin, northern Canada, is characterized by thick, deep marine turbidite deposits not observed in timeequivalent, intracratonic basin units further southwest. Models invoked to explain this feature include development of a full-ocean, back-arc, or proto-ocean basin followed by turbidite sedimentation. We present new and existing U-Pb geochronological, Nd isotope, geochemical, and stratigraphic evidence that support a proto-ocean basin model, and we explore the events leading to the formation and closure of such a rift basin during the middle Paleoproterozoic. Sedimentation initiated largely after ca. 2160 Ma with deposition of craton-derived, shallow marine siliciclastic strata (Dewar Lakes formation). Continued extension resulted in accumulation of south-facing carbonate beds (Flint Lake formation) and likely concomitant, arclike tholeiitic to picritic volcanism and voluminous volcani clastic sedimentation (lower Bravo Lake formation) farther outboard at ca. 1980 Ma. Accumulation of intra basinal siliciclastic strata above lower Bravo Lake formation rocks may mark a hiatus in mafi cultramafic magmatism. By ca. 1923 Ma, upper Bravo Lake formation, within-platetype alkaline sill emplacement and vol canism occurred within highly extended crust. The oceanic island basalt-like signatures of the Bravo Lake formation rocks (but lack of depleted, mid-ocean-ridge basalt-type compositions) suggest that by this time the thinned Rae continental lithosphere had fragmented into small crustal block(s) and narrow zone(s) of incipient oceanic crust farther outboard of the Piling Group basin. Rapid subsidence of the southeastern Rae margin ensued, leading to deposition of euxinic (Astarte River formation) and overlying turbiditic strata (Longstaff Bluff formation). The post-ca. 1915 Ma northern turbiditic sedimentary units were likely derived from a thoroughly mixed, two-component source with possible input from the Snowbird tectonic zone and Bravo Lake formation, whereas the post-ca. 1930 Ma southern turbidite unit may have been sourced from the Meta Incognita microcontinent, presently exposed further south. We favor a rift margin over a foreland basin setting for the deposition of the northern turbidite deposits. Subsequent mantle upwelling associated with incipient ocean formation may have triggered melting of highly thinned continental crust resulting in emplacement of latestage, ca. 1897 Ma, contaminated rapakivi granite and highly differentiated mafi c sills. Our results are most consistent, albeit not exclusively, with the much debated model of asthenospheric upwelling and incipient rifting along the Rae-Hearne boundary farther southwest at ca.

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“…The onset of foredeep subsidence is sedimentologically most apparent when the outer shelf of a passive margin enters the trench, by which time the continental rise will have already passed beneath the trench axis in most cases. Passivemargin shelf-to-foredeep transitions of Orosirian age have been recognized throughout proto-Laurentia (Hoffman 1987;Partin et al 2014) and some are tightly constrained chronometrically from U-Pb dating of tuffs (Bowring and Grotzinger 1992). Metamorphic dates from passive-margin protoliths provide minimum constraints on collision age.…”

Section: Orosirian Collision Ages and Subduction Polaritiesmentioning

confidence: 99%

“…This segment of the orogen includes three episodes of collision (Wardle et al 2002;van Gool et al 2002;St-Onge et al 2006Berman et al 2013;Corrigan et al 2009;Corrigan 2013;Eglington et al 2013;Pehrsson et al 2013a;Partin et al 2014). The first, 1.88-1.86 Ga, involved the accretion of Archean microcontinents (Sugluk, Meta Incognita, Southeast Churchill Core Zone, Disco and North Atlantic) to the Rae craton.…”

Section: Trans-hudson Orogenmentioning

confidence: 99%

The Origin of Laurentia: Rae Craton as the Backstop for Proto-Laurentian Amalgamation by Slab Suction

Hoffman

2014

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Proto-Laurentia (i.e. pre-Grenvillian Laurentia) is an aggregate of six or more formerly independent Archean cratons that amalgamated convulsively in geons 19 and 18 (Orosirian Period), along with non-uniformly distributed areas of juvenile Paleoproterozoic crust. Subduction polarities and collision ages have been provisionally inferred between the major cratons (and some minor ones), most recently between the Rae and Hearne cratons. The oldest Orosirian collisions bound the Rae craton: 1.97 Ga (Taltson-Thelon orogen) in the west, and 1.92 Ga (Snowbird orogen) in the southeast. All other Orosirian collision ages in proto-Laurentia are < 1.88 Ga. The Rae craton was the upper plate during (asynchronous) plate convergence at its western and, tentatively, southeastern margins. Subsequent plate convergence in the Wopmay and Trans-Hudson orogens was complex, with the Rae craton embedded in the lower plate prior to the first accretion events (Calderian, Reindeer and Foxe orogenies), but in the upper plate during major subsequent convergence and terminal collisions, giving rise to the Great Bear and Cumberland magmatic arcs, respectively. The ‘orthoversion’ theory of supercontinental succession postulates that supercontinents amalgamate over geoidal lows within a meridional girdle of mantle downwellings, orthogonal to the lingering superswell at the site of the former supercontinent. If the downwelling nodes develop through positive feedback from the descent of cold oceanic slabs, then viscous traction should contribute to drawing the cratons together over the downwelling node. Viewed in this way, the Rae craton was the first to settle over the downwelling node and became the backstop for the other cratons that were drawn towards it by subduction. It was, literally, the origin of Laurentia. Whether the Rae craton was also the origin of Nuna, the hypothetical cogenetic supercontinent, depends on ages and subduction polarities of Orosirian sutures beyond proto-Laurentia.SOMMAIRELa proto-Laurentie (c.-à-d. la Laurentie pré-grenvillienne) est un agrégat d’au moins six cratons archéens indépendants qui se sont amalgamés convulsivement durant les géons 19 et 18 (Orosirien), le long de zones de croûtes juvéniles paléoprotérozoïques réparties de manière hétérogène. Les polarités de subduction et les âges de collision entre les grands cratons (et d’autres moins grands) ont été provisoirement déduits, le plus récemment entre le craton de Rae et le craton de Hearne. Les plus anciennes collisions orosiriennes ont soudé le craton de Rae : 1,97 Ga (orogène de Taltson-Thelon) dans l’ouest, et 1,92 Ga (orogène de Snowbird) dans le sud-est. Tous les autres âges de collision en proto-Laurentie sont inférieurs à 1,88 Ga. Le craton de Rae constituait la plaque supérieure durant la convergence de plaque (asynchrone) à sa marge ouest, et peut-être aussi à ses marges sud-est. La convergence de plaque subséquente dans les orogènes de Wopmay et Trans-Hudson a été complexe, le craton de Rae étant encastré dans la plaque inférieure avant les premiers événements d’accrétion (orogènes caldérienne, de Reindeer et de Fox), puis dans la plaque supérieure durant la grande convergence subséquente et les collisions terminales, ce qui a créé les arcs magmatiques de Great Bear et de Cumberland respectivement. La théorie de « l’orthoversion » de la succession des supercontinents présuppose que les supercontinents s’amalgament au-dessus de creux géoïdaux en deça d’une gaine méridienne de convections mantéliques descendantes, à angle droit d’un super-renflement persistant au site d’un ancien supercontinent. Si le nœud de convection descendante s’établit par rétroaction positive de la descente de plaques océaniques froides, la traction visqueuse devrait contribuer à entraîner les cratons ensembles au-dessus du nœud de convection descendante. Vu de cette façon, le craton de Rae a été le premier à s’établir au-dessus du nœud de convection descendante, ce qui en a fait la butée des autres cratons entraînés par la subduction. Littéralement, telle a été l’origine de la Laurentie. Quant à savoir si c’est le craton de Rae qui a été à l’origine de Nuna, cet hypothétique surpercontinent cogénétique, cela dépend des âges et des polarités de subduction des sutures orosiriennes au-delà de la proto-Laurentie.

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Sedimentological and geochemical basin analysis of the Paleoproterozoic Penrhyn and Piling groups of Arctic Canada

Cited by 30 publications

References 67 publications

The effects of metamorphism on iron mineralogy and the iron speciation redox proxy

The effects of metamorphism on iron mineralogy and the iron speciation redox proxy

Did a proto-ocean basin form along the southeastern Rae cratonic margin? Evidence from U-Pb geochronology, geochemistry (Sm-Nd and whole-rock), and stratigraphy of the Paleoproterozoic Piling Group, northern Canada

The Origin of Laurentia: Rae Craton as the Backstop for Proto-Laurentian Amalgamation by Slab Suction

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