40Ar39Ar geochronology of Tertiary mafic intrusions along the East Greenland rifted margin: Relation to flood basalts and the Iceland hotspot track

Tegner, Christian; Duncan, Robert A.; Bernstein, Stefan; Brooks, C. Kent; Bird, Dennis K.; Storey, Michael

doi:10.1016/s0012-821x(97)00206-9

Cited by 162 publications

(105 citation statements)

References 51 publications

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“…1a;Nielsen 2004;Svennevig and Guarnieri 2012;Salmonsen and Tegner 2013). It was emplaced at 56.02 Ma (Wotzlaw et al 2012) during widespread Paleogene magmatic activity associated with the opening of the North Atlantic Ocean and passage of Greenland over the proto-Iceland plume (e.g., Brooks and Nielsen 1982;Tegner et al 1998;Saunders et al 1997;Momme et al 2002). It crystallized under closed-system conditions from a single, homogenized magma body and is the type locality for igneous layering (e.g., Wager and Brown 1968;McBirney 1989;Irvine et al 1998;Holness et al 2007;Tegner et al 2009;Thy et al 2009;McKenzie 2011;Holness et al 2011).…”

Section: Geological Setting Of the Platinova Reef Skaergaard Intrusionmentioning

confidence: 99%

Extreme enrichment of Se, Te, PGE and Au in Cu sulfide microdroplets: evidence from LA-ICP-MS analysis of sulfides in the Skaergaard Intrusion, east Greenland

Holwell

Keays

McDonald

et al. 2015

Contrib Mineral Petrol

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evidence implies that there is no significant post-magmatic hydrothermal S loss and that the metal profiles are essentially a function of magmatic processes. We propose that to generate these extreme precious and semimetal contents, the sulfides must have formed from an anomalously metal-rich package of magma, possibly formed via the dissolution of a previously PGE-enriched sulfide. Other processes such as kinetic diffusion may have also occurred alongside this to produce the ultra-high tenors. The characteristic metal offset pattern observed is largely controlled by partitioning effects, producing offset peaks in the order Pt+Pd>Au>Te>Se>Cu that are entirely consistent with published D values. This study confirms that extreme enrichment in sulfide droplets can occur in closed-system layered intrusions in situ, but this will characteristically form ore deposits that are so low in sulfide that they do not conform to conventional deposit models for Cu-Ni-PGE sulfides which require very high R factors, and settling of sulfide liquids.

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Section: Geological Setting Of the Platinova Reef Skaergaard Intrusionmentioning

confidence: 99%

Extreme enrichment of Se, Te, PGE and Au in Cu sulfide microdroplets: evidence from LA-ICP-MS analysis of sulfides in the Skaergaard Intrusion, east Greenland

Holwell

Keays

McDonald

et al. 2015

Contrib Mineral Petrol

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“…The high-velocity crustal 'seaward dipping reflectors series' (SDRS) discovered in seismic lines (see [75]), with a total volume (extruded part) in excess of 2 Mkm 3 , correspond to mainly subaerially erupted basalts (with minor trachyte dykes); their volume (close to 10 Mkm 3 in [48]) is well constrained, but corresponds to the deeper, mid-and lower crustal components that cannot be included in volume estimates for pre-rift CFBs (see introduction and Table 1). Tegner et al [176] dated mafic intrusions by 40 Ar/ 39 Ar along the eastern-Greenland rifted margin. They find that tholeiitic magmatism occurred in three discrete pulses at ∼62-59 Ma, 57-54 Ma, and 50-47 Ma, related to melting episodes triggered respectively by plume impact, continental breakup, and passage of the plume axis.…”

Section: The Brito-arctic Provincementioning

confidence: 99%

On the ages of flood basalt events

Courtillot

Renne

2003

Comptes Rendus. Géoscience

744

400

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We review available data constraining the extent, volume, age and duration of all major Phanerozoic continental flood basalts (CFB or traps) and oceanic plateaus (OP), together forming the group of large igneous provinces (LIP), going from the smallest Columbia flood basalts at ∼16 Ma to the as yet ill-known remnants of a possible trap at ∼360 Ma in eastern Siberia. The 16 traps (CFB and OP) reviewed form a rather unimodal distribution with an initial modal volume of the order of 2.5 Mkm 3 . Most provinces agree with a rather simple first order model in which volcanism may have lasted of the order of 10 Ma, often resulting in continental break-up, but where most of the volume was erupted in about 1 Ma or sometimes less. This makes CFBs/OPs (LIPs) major geodynamic events, with fluxes exceeding the total output of present day hot spots and even possibly exceeding over short times the entire crustal production of mid-ocean ridges. The proposed correlation between trap ages and the ages of several geological events, including mass extinctions and oceanic anoxia, is found to have improved steadily as more data have become available, to the point that the list of trap ages may coincide with many major divisions in the geological time scale. The four largest mass extinctions in the last 260 Ma coincide to the best resolution available with four traps, making a causal connection between the two through some form of catastrophic climatic perturbations the most likely hypothesis. The time sequence of LIPs appears to have been random and there is no robust evidence for long time trends in the corresponding crustal production rate over the last 260 Ma.  2003 Académie des sciences/Éditions scientifiques et médicales Elsevier SAS. All rights reserved. RésuméNous passons en revue l'ensemble des données qui permettent de contraindre l'étendue, le volume, l'âge et la durée de toutes les grandes provinces magmatiques basaltiques (en anglais LIP) d'âge Phanérozoïque, qu'il s'agisse des trapps ou plateaux basaltiques continentaux (en anglais CFB) ou des plateaux océaniques (OP), allant de la plus récente et plus petite (le plateau de Columbia âgé de ∼16 Ma) à l'une des plus anciennes, encore mal connue, située dans l'Est de la Sibérie et sans doute âgée de ∼360 Ma. Les 16 provinces passées en revue forment une distribution assez unimodale, avec des volumes initiaux de lave de l'ordre de 2,5 Mkm 3 . La plupart des provinces sont compatibles, au premier ordre, avec un modèle simple selon lequel le volcanisme a pu durer une dizaine de millions d'années et a en général conduit à une déchirure des continents et à l'ouverture d'un nouveau bassin océanique, mais où l'essentiel du volume des laves a été émis en environ 1 million d'années, parfois moins. Ceci fait des trapps (des LIP en général) des événements géodynamiques majeurs, avec des flux de matière ayant dépassé la production totale actuelle des points chauds et même, peut-être, pendant de brefs intervalles, la totalité de la production de croûte V.E. Courtillot, P.R. Renn...

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“…The lower volcanics were erupted during the earliest stages of continental break-up (61-57 Ma; Nielsen et al, 1981;Storey et al, 1996;Tegner et al, 1998;Hansen et al, 2002) and represent c. 15% of the preserved volume (Ukstins Peate et al, 2003a). Primary MVDs (Fig.…”

Section: East Greenlandmentioning

confidence: 99%

Mafic volcaniclastic deposits in flood basalt provinces: A review

Ross

Ukstins

McClintock

et al. 2005

Journal of Volcanology and Geothermal Research

137

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Flood volcanic provinces are assumed generally to consist exclusively of thick lavas and shallow intrusive rocks (mostly sills), with any pyroclastic rocks limited to silicic compositions. However mafic volcaniclastic deposits (MVDs) exist in many provinces, and the eruptions that formed such deposits are potentially meaningful in terms of potential atmospheric impacts and links with mass extinctions. The province where MVDs are the most voluminousthe Siberian Traps -is also the one temporally associated with the greatest Phanerozoic mass extinction. A lot remains to be learned about these deposits and eruptions before a convincing genetic link can be established, but as a first step, this contribution reviews in some detail the current knowledge on MVDs for the provinces in which they are better known, i.e. the North Atlantic Igneous Province (including Greenland, the Faeroe Islands, the British Isles, and tephra layers in the North Sea basin and vicinity), the Ontong Java plateau, the Ferrar, and the Karoo. We also provide a brief overview of what is known about MVDs in other provinces such as the Columbia River Basalts, the Afro-Arabian province, the Deccan Traps, the Siberian Traps, the Emeishan, and an Archean example from Australia. The thickest accumulations of MVDs occur in flood basalt provinces where they underlie the lava pile (Faeroes: >1 km, Ferrar province: ≥400 m, Siberian Traps: 700 m). In the Faeroes case, the great thickness of MVDs can be attributed to accumulation in a local sedimentary basin, but in the Ferrar and Siberian provinces the deposits are widespread (>3 x 10 5 km 2 for the latter). On the Ontong Java plateau over 300 m of MVDs occur in one drill hole without any overlying lavas. Where the volcaniclastic deposits are sandwiched between lavas, their thickness is much less. In most of the cases reviewed, primary MVDs are predominantly of phreatomagmatic origin, as indicated by the clast assemblage generally consisting of basaltic clasts of variable vesicularity (dominantly non-to poorly-vesicular) mixed with abundant country rock debris. The accidental lithic components often include loose quartz particles derived from poorly consolidated sandstones in underlying sedimentary basins (East Greenland, Ferrar, Karoo). These underlying sediments or sedimentary rocks were not only a source for debris but also aquifers that supplied water to fuel phreatomagmatic activity. In the Paraná-Etendeka, by contrast, the climate was apparently very dry when the lavas were emplaced (aeolian sand dunes) and no MVDs are reported. Volcanic vents filled with mafic volcaniclastic material, a few tens of metres to about 5 km across, are documented in several provinces (Deccan, North Atlantic, Ferrar, Karoo); they are though to have been excavated in relatively soft country rocks (rarely in flood lavas) by phreatomagmatic activity in a manner analogous to diatreme formation.

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40Ar39Ar geochronology of Tertiary mafic intrusions along the East Greenland rifted margin: Relation to flood basalts and the Iceland hotspot track

Cited by 162 publications

References 51 publications

Extreme enrichment of Se, Te, PGE and Au in Cu sulfide microdroplets: evidence from LA-ICP-MS analysis of sulfides in the Skaergaard Intrusion, east Greenland

Extreme enrichment of Se, Te, PGE and Au in Cu sulfide microdroplets: evidence from LA-ICP-MS analysis of sulfides in the Skaergaard Intrusion, east Greenland

On the ages of flood basalt events

Mafic volcaniclastic deposits in flood basalt provinces: A review

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