Origin of the Tulameen ultramafic-gabbro complex, southern British Columbia

Findlay, D C

doi:10.1139/e69-040

Cited by 51 publications

(28 citation statements)

References 24 publications

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“…Furthermore, the emplacement of the mafic magmas of the complex is coeval with granitoid magmatism (Sutcliffe 1989). The intrusion is similar in form to mafic intrusions associated with orogenic terrains such as the Mesozoic Alaskan complexes (Taylor 1967;Findlay 1969). The PGE mineralization in the Roby Zone of the LDIC is associated with sulphides and altered silicates in gabbroic rocks.…”

Section: Introductionmentioning

confidence: 83%

The Lac des Iles Complex, Ontario: petrology and platinum-group-elements mineralization in an Archean mafic intrusion

Sutcliffe¹,

Sweeny²,

Edgar³

1989

Can. J. Earth Sci.

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The Lac des Iles Complex is a late Archean, mafic to ultramafic complex that is host to 20.4 X lo6 t Pt, Pd, and Au mineralization with an average grade of 6.34 g/t platinum-group elements (PGE). The 30 km2 complex, located in the Wabigoon Subprovince, consists of several coalescing mafic to ultramafic intrusive centers. The complex is emplaced into early gneissic tonalite and is contemporaneous with late granitoids.The magmatic evolution of the complex reflects the emplacement of multiple pulses of previously fractionated magma, some of which underwent subsequent in situ fractionation. Distinct magma sequences are recognized on the basis of intrusive relationships, differences in the cumulus minerals, crystallization order, and trace-element chemistry. These sequences are (1) hornblende gabbro, (2) gabbro and gabbronorite, and (3) ultramafic. Where there is evidence of intrusive relations, the most primitive sequences are emplaced late and occur toward the north end of the complex. Microprobe analyses indicate the following compositional ranges of mineral phases within the complex: ~livine-Fo,-,~, orthopyroxene-En,2~67Fs,5530W02~3, and clinopyroxene-En,,~46Fs3~12W041~51. Cyclic layering is developed only in the northern ultramafic part of the complex where several cycles of mesocumulate-to adcumulate-textured wehrlite, clinopyroxenite, and websterite are identified.Although the parental magma compositions are not well constrained, model calculations using major-element and rare-earthelement (REE) contents of cumulus phases and adcumulate rocks indicate that the parental magmas had mol MgOl(Mg0 + FeO) ranging from at least 0.61 to 0.54 and had fractionated REE abundances with CeN/YbN of approximately 5.0. Mineral chemistry and crystallization sequences indicate that the ultramafic and gabbroic parts of the complex had tholeiitic basalt parental magmas of picritic and high-alumina affinities, respectively. The major FGE mineralization at Lac des Iles occurs in the Roby Zone along the interface between the gabbro and gabbronorite in the southern part of the complex. This interface has been intruded by a sheet of pyroxene cumulate, which is probably part of the ultramafic sequence. The PGE sulphide mineralization in the Roby Zone is associated with disseminated chalcopyrite, pyrrhotite, pentlandite, pyrite, and altered silicates in (1) the pyroxene cumulate sheet, (2) the mixed gabbrogabbronorite, and (3) the gabbroic pegmatite dikes and breccia zones. C1-rich apatite and monazite are accessory phases associated with PGE mineralization. PGE occurrences are also present within sulphide-bearing orthopyroxene-clinopyroxene cumulates in the northern ultramafic part of the complex. The Roby Zone mineralization is localized by mixing the PGE and sulphide-rich gabbronorite and pyroxene cumulates with the volatile-rich gabbro. The FGE are redistributed by late magmatic volatile activity, which generated mineralized gabbroic pegmatites and breccia zones.Le complex du Lac des Iles est un complexe mafique ii ultramafique, d'ig...

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Section: Introductionmentioning

confidence: 83%

The Lac des Iles Complex, Ontario: petrology and platinum-group-elements mineralization in an Archean mafic intrusion

Sutcliffe¹,

Sweeny²,

Edgar³

1989

Can. J. Earth Sci.

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“…Alaskan-type complexes, as described by Ruckmick and Noble (1959), Noble (1960, 1969), Irvine (1967Irvine ( , 1974, Taylor (1967), Findlay (1969), Murray (1972), and more recently by Brown et aL (1988), are generally relatively small intrusions that expose ultramafic rocks concentrically zoned around a central dunite body. Their compositional characteristics are distinctive: ideally, the cumulus rock series include dunite, wehrlitic peridotite, olivine clinopyroxenite, magnetite hornblende clinopyroxenite, and hornblende gabbro; orthopyroxene is sparse in these assemblages.…”

Section: Isotopic Datamentioning

confidence: 96%

Mineral chemistry and geochronology of the potassic alkaline ultramafic Inagli complex, Aldan Shield, eastern Siberia

Mues-Schumacher¹,

Keller²,

Kononova

et al. 1996

Mineral. mag.

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The Inagli complex, one of several Mesozoic intrusive complexes of the Aldan Shield (Siberian Platform), exhibits a concentric structure comprising several alkaline ultramafic rock-types. A central dunite body is surrounded by olivine-and phlogopite-clinopyroxenites forming an inner rirrr. The outer rim consists of different shonkinitic and malignitic rocks. The K-At ages obtained for the whole complex vary around 132 Ma.The dunites and clinopyroxenites are characterized by cumulate textures. With increasing modal abundances of clinopyroxene and subordinate phlogopite, the rocks develop to olivine-clinopyroxenite, shonkinite, and malignite with intercumulus potassium feldspar. Mineralogical characterization of the rocks suggests they evolved by fractional crystallization. The highly forsteritic olivines (Fo up to 95) require a melt as magnesian as rag# 87.1, representing --+26 wt.% MgO. The parental melt is likely to be an olivine-, H20-and K20-rich picritic liquid of shoshonitic character. Major and trace element systematics show high LILE/ LREE and LREE/HFSE ratios indicating the involvement of a subduction zone component in the genesis of these rocks.

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“…Middle Eocene Needle Peak pluton-The Middle Eocene Needle Peak pluton underlies much of the west-central margin > 100 km, encompasses the belt of deformed rocks of the Eagle Plutonic Complex, Nicola Group, and Tulameen ultramafic complex (Findlay 1969;Nixon and Rublee 1988) (Fig. 2).…”

Section: Coquihalla Volcanic Complexmentioning

confidence: 99%

Jurassic and Cretaceous plutonic and structural styles of the Eagle Plutonic Complex, southwestern British Columbia, and their regional significance

Greig¹

1992

Can. J. Earth Sci.

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The Eagle Plutonic Complex is an elongate north-northwest-trending body of deformed Middle to Late Jurassic and middle Cretaceous rocks which underlies the southwestern margin of the Intermontane terrane. New mapping of the complex and its country rocks, in concert with geochronometry, has defined episodes of contractional, ductile deformation in the Middle to Late Jurassic and middle Cretaceous, as well as brittle deformation in Tertiary time. Synkinematic Middle to Late Jurassic Eagle tonalite at the eastern margin of the Eagle Complex intrudes mylonitic Nicola Group rocks and structurally overlies them along a southwest-dipping belt of high strain (Eagle shear zone) with a structural thickness of > 1 km and a strike length of > 100 km. In the central and western Eagle Complex, Eagle tonalite grades into tonalite orthogneiss (Eagle gneiss), and both are crosscut by mid-Cretaceous, muscovite-bearing plutons of the Fallslake Plutonic Suite. Fallslake Suite rocks are themselves ductilely deformed along the Pasayten fault, which bounds the Eagle Complex on the west and was active mainly in the mid-Cretaceous (ductile deformation with sinistral, east-side-up, reverse displacement). The Jurassic and Cretaceous episodes of deformation may reflect the respective initial and final stages of the accretion of the Insular terrane to the North American margin. West of the Pasayten fault, Middle to Late Jurassic and older(?) rocks of the Zoa Complex are structurally overlain, in part, by deformed Middle Eocene and middle Cretaceous sedimentary rocks. In the north, the Middle Eocene rocks are intruded on their west side by the Middle Eocene Needle Peak pluton.

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Origin of the Tulameen ultramafic-gabbro complex, southern British Columbia

Cited by 51 publications

References 24 publications

The Lac des Iles Complex, Ontario: petrology and platinum-group-elements mineralization in an Archean mafic intrusion

The Lac des Iles Complex, Ontario: petrology and platinum-group-elements mineralization in an Archean mafic intrusion

Mineral chemistry and geochronology of the potassic alkaline ultramafic Inagli complex, Aldan Shield, eastern Siberia

Jurassic and Cretaceous plutonic and structural styles of the Eagle Plutonic Complex, southwestern British Columbia, and their regional significance

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