The age of the ferropicritic volcanics and comagmatic Ni-bearing intrusions at Pechenga, Kola Peninsula, U.S.S.R.

Hanski, Eero; Huhma, H.; Smolkin, V. F.; Vaasjoki, Matti

doi:10.17741/bgsf/62.2.003

Cited by 73 publications

(30 citation statements)

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“…2.0 Ga komatiites in the Central Lapland Greenstone Belt in northern Finland (Hanski et al, 2001); as ferropicritic lavas and dikes in the ca. 2.0 Ga Pechenga belt in northwestern Russia (Hanski, 1992;Hanski et al, 1990;Hanski & Smolkin 1995); as lavas in the 1.9-1.8 Ga Svecofennian orogen (Makkonen, 1996;Bergström, 1997;Väi sä-nen & Mänttäri, 2002; this study); as dikes in the 1.88 Ga Cape Smith belt, Canada (Mungall, 2007); and among the 1.11 Ga Keneewanan basaltic volcanic and subvolcanic rocks of North America (Sutcliffe, 1987;Klewin & Shirley, 1992).…”

Section: Introductionmentioning

confidence: 65%

The Salittu Formation in southwestern Finland, part II: Picritic-basaltic volcanism in mature arc environment

Nironen¹

2017

Bull Geol Soc Finland

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The Salittu Formation is one of the few metavolcanic successions in the Svecofennian orogen that contain ultramafic rocks. New samples were collected from the picritic and basaltic rocks as well as spatially associated gabbroic rocks, and their major and trace element compositions are presented and discussed here. Although the metavolcanic rocks have experienced primary alteration and two metamorphic events, elements that are insensitive to alteration (rare earth elements, Zr, Nb, Ni) have been used to infer their source and evolution. Based on the similar shapes of the rare earth element patterns in the metabasalt and metapicrite, basaltic melt derived from picritic one by fractional crystallization. The high Ni and Mg contents, Ni/MgO and Zr/Nb ratios, and multielement patterns make a slightly enriched garnet lherzolite a likely source for the metapicrite. With the exception of synvolcanic gabbros within the metavolcanic rocks, the gabbroic intrusions at Salittu have no genetic link to the metavolcanic rocks.Geochemical comparison with modern basalts suggests that the picritic and basaltic melts were generated in a mature arc environment during a rifting event. Picritic melt rose from convective mantle to the crust and formed a magma chamber. Basaltic melt fractionated in the chamber and extruded upon an earlier formed volcanic pile as basalt and synvolcanic gabbro. Soon after extrusion of the basalt, picritic melts, similar in composition to the earlier picrite, rose through the crust and extruded on top of the basalt.Comparison with three other metapicrite occurrences in southern Finland suggests that although the occurrences may be considered broadly comagmatic, each had their specific sources and probably also tectonic environments during emplacement.

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Section: Introductionmentioning

confidence: 65%

The Salittu Formation in southwestern Finland, part II: Picritic-basaltic volcanism in mature arc environment

Nironen¹

2017

Bull Geol Soc Finland

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“…Detrital zircon grains sampled from near the base of the Pilgujärvi SF, provide a maximum age to deposition of 1922.8 ± 1.6 Ma (ID-TIMS, and various single isochron methods on mafic intrusions and organic-rich shales provide a range of ages between 2231 and 1924 Ma (Hanski et al, 1990, Walker et al, 1997and Hannah et al, 2006, with the older ages inferred to be due to inheritance . Zircon grains in a tuff in the Pilgujärvi Volcanic Formation, immediately overlying the Pilgujärvi SF, have yielded a 1919.2 ± 1.3 Ma age .…”

Section: Geological Settingmentioning

confidence: 99%

“…The age of the Pilgujärvi SF is broadly constrained between 1.98 and 1.92 Ga (Hanski et al, 1990, Hanski et al, 2014, Hannah et al, 2006. Whereas Zaonega phosphates occur mainly in situ, forming layers and lenses in bedded mudstones, the Pilgujärvi SF phosphates occur as detrial, phosphatic, sand-togravel/pebble size grains transported and redeposited either in environments interpreted to range from deltaic ( Bekasova, 1985) to continental slope turbidite fan settings ( Akhmedov andKrupenik, 1990 andSturt, 1998).…”

Section: Introductionmentioning

confidence: 99%

Petrography and the REE-composition of apatite in the Paleoproterozoic Pilgujärvi Sedimentary Formation, Pechenga Greenstone Belt, Russia

Joosu

Lepland

Kreitsmann

et al. 2016

Geochimica et Cosmochimica Acta

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The first globally significant phosphorous-rich deposits appear in the Paleoproterozoic at around 2 Ga, however, the specific triggers leading to apatite precipitation are debated. We examine phosphorous-rich rocks (up to 8 wt% P 2 O 5 ) in 1.98-1.92 Ga old Pilgujärvi Sedimentary Formation, Pechenga Greenstone Belt, Russia. Phosphates in these rocks occur as locally derived and resedimented sand-to-gravel/pebble sized grains consisting of apatitecemented muddy sediments. Phosphatic grains can be subdivided into four petrographic types (A-D), each has a distinct REE signature reflecting different early-to-late diagenetic conditions and/or metamorphic overprint. Pyrite containing petrographic type D, which typically has a flat REE pattern, negative Ce anomaly and positive Eu anomaly, is the best preserved of the four types and best records conditions present during apatite precipitation. Type D phosphatic grains precipitated under (sub)oxic basinal conditions with a significant hydrothermal influence. These characteristics are similar to Zaonega Formation phosphates of NW Russia's Onega Basin, and consistent with phosphogenesis triggered by the development of anoxic(sulfidic)-(sub)oxic redoxclines at shallow sediment depth during the Paleoproterozoic.

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“…1 -ферропикриты (а) и Пильгуярвинская габброверлитовая интрузия (б) Печенгской структуры [Hanski et al, 1990]; 2 -Мончегорский плутон [Mitrofanov, Smol'kin, 2004b]; 3 -Мончетундровский массив [Mitrofanov, Smol'kin, 2004b; Nerovich et al, 2009]; 4 -Федорово Панский комплекс [Balashov et al, 1993; Serov, 2008; 5 -Имандровский комплекс [Balashov et al, 1993]; 6 -расслоенные интрузии Ка релии и Финляндии [Amelin, Semenov, 1996; Berkovskii et al, 2000; Huhma et al, 1990]; 7 -кислые метавулканиты сейдореченской свиты ИВС [Chashchin et al, 2008]; 8 -вулканиты позднеархейских зеленокаменных поясов Кольского полуострова и Карелии [Vrevsky et al, 2003; Puchtel et al, 1999; Svetov, Huhma, 1999]; 9 -тренд эволюции величины ε Nd в мантийных резервуарах. CHUR -однородный хонд ритовый резервуар, MORB -базальты срединноокеанических хребтов по модели [Smith, Ludden, 1989], AR -область эволюции архей ской коры по [Patchett, Bridgwater, 1984].…”

Section: минерагенияunclassified

“…CHUR -однородный хонд ритовый резервуар, MORB -базальты срединноокеанических хребтов по модели [Smith, Ludden, 1989], AR -область эволюции архей ской коры по [Patchett, Bridgwater, 1984]. 1 -ferropicrites (a) and Pilguyarvi gabbrowehrlite intrusion (б) of the Pechenga structure [Hanski et al, 1990]; 2 -Monchepluton [Mitrofanov, Smol'kin, 2004b]; 3 -Monchetundra massif [Mitrofanov, Smol'kin, 2004b; Nerovich et al, 2009]; 4 -FedorovoPansky complex [Balashov et al, 1993; Serov, 2008; 5 -Imandra complex [Balashov et al, 1993]; 6 -layered intrusions of Karelia and Finland [Amelin, Semenov, 1996; Ber kovskii et al, 2000; Huhma et al, 1990]; 7 -acid metavolcanites of IVS Seydorechka suite [Chashchin et al, 2008]; 8 -volcanites of Late Ar chaean greenstone belts of the Kola peninsula and Karelia [Vrevsky et al, 2003; Puchtel et al, 1999; Svetov, Huhma, 1999]; 9 -evolution trend of magnitude ε Nd in mantle reservoirs. CHUR -homogeneous chondritic reservoirs, MORB -basalts of midoceanic ridges according to the model by [Smith, Ludden, 1989], AR -Archaean crust evolution area according to [Patchett, Bridgwater, 1984].…”

Section: минерагенияmentioning

confidence: 99%

The Paleoproterozoic Imandra-Varzuga rifting structure (Kola Peninsula): intrusive magmatism and minerageny

Chashchin¹,

Mitrofanov²

2014

Geodyn. Tectonophys.

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The article provides data on the structure of the Paleoproterozoic intercontinental ImandraVarzuga rifting structure (IVS) and compositions of intrusive formations typical of the early stage of the IVS development and associated mineral resources. IVS is located in the central part of the Kola region. Its length is about 350 km, and its width varies from 10 km at the flanks to 50 km in the central part. IVS contains an association of the sedimentaryvolcanic, intrusive and dyke com plexes. It is a part of a large igneous Paleoproterozoic province of the Fennoscandian Shield spreading for a huge area (about 1 million km 2 ), which probably reflects the settings of the head part of the mantle plume. Two age groups of layered intru sions were associated with the initial stage of the IVS development. The layered intrusions of the FedorovoPansky and Monchegorsk complexes (about 2.50 Ga) are confined to the northern flank and the western closure of IVS, while intrusions of the Imandra complex (about 2.45 Ga) are located at the southern flank of IVS. Intrusions of older complexes are composed of rock series from dunite to gabbro and anorthosites (Monchegorsk complex) and from orthopyroxenite to gabbro and anor thosites (FedorovoPansky complex). Some intrusions of this complexes reveal features of multiphase ones. The younger Imandra complex intrusions (about 2.45 Ga) are stratified from orthopyroxenite to ferrogabbro. Their important feature is comagmatical connection with volcanites. All the intrusive complexes have the boninitelike mantle origin enriched by litho phyle components. Rocks of these two complexеs with different age have specific geochemical characteristics. In the rocks of the Monchegorsk and FedorovoPansky complexes, the accumulation of REE clearly depends on the basicity of the rocks, the spectrum of REE is nonfractionated and 'flat', and the Eu positive anomaly is slightly manifested. In the rocks of the Imandra complex, the level of REE accumulation is relatively higher. The spectrum of REE here differs with more fraction ated LREE with a 'flat' distribution of HREE and distinct Eu anomalies. Rocks of all the intrusive complexes are character ized mostly by negative ε Nd (T) values, and ε Nd values are distributed more heterogeneously in the rocks of the Monchegorsk complex than in the rocks of the FedorovoPansky complex. Deposits and occurrences of Cr, complex PGECuNi and low sulfide PtPd ores of the world class are spatially related and genetically associated with the IVS intrusive complexes. The Sopcheozero deposit (Monchepluton of the Monchegorsk complex) and Bolshaya Varaka deposit (the samename intrusion of the Imandra complex) represent a layered Cr mineralization. Complex PGECuNi deposits are confined to Monchepluton. They occur in vein ores of the NittisKumuzhyaTravyanaya massifs (which have been worked out) and Sopcha, vein PGE Cu, injecting Ni ores mostly and bottom deposits of the NittisKumuzhyaTravyanaya massifs, as well as in the Nyud 'criti cal' horizon. In the past 10-15 year...

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The age of the ferropicritic volcanics and comagmatic Ni-bearing intrusions at Pechenga, Kola Peninsula, U.S.S.R.

Cited by 73 publications

References 1 publication

The Salittu Formation in southwestern Finland, part II: Picritic-basaltic volcanism in mature arc environment

The Salittu Formation in southwestern Finland, part II: Picritic-basaltic volcanism in mature arc environment

Petrography and the REE-composition of apatite in the Paleoproterozoic Pilgujärvi Sedimentary Formation, Pechenga Greenstone Belt, Russia

The Paleoproterozoic Imandra-Varzuga rifting structure (Kola Peninsula): intrusive magmatism and minerageny

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