First published: 21 April 2021
Last modified:
DISCLAIMER: This English version is translated from the original French. In case of any discrepancy, the French version shall prevail.
| Author(s): | Frarey and Duffell, 1964 |
| Age: | Paleoproterozoic |
| Stratotype: | None |
| Type area: | Willbob Lake area (NTS sheet 23O01) |
| Geological province: | Churchill Province |
| Geological subdivision: | New Quebec Orogen (Labrador Trough) / Letty Lithotectonic Zone |
| Lithology: | Basalt, breccia, tuff, mudstone, iron formation, tholeiite, schist |
| Category: | Lithostratigraphic |
| Rank: | Formation |
| Status: | Formal |
| Use: | Active |
Background
Volcanic rocks of this unit were originally included in an undivided volcano-sedimentary unit called the « Doublet Series » by Labrador Mining and Exploration geologists (1949, in Frarey and Duffell, 1964), then the Doublet group by Harrison (1952). Frarey and Duffell (1964) later formalized the name Doublet Group and introduced the name Willbob Formation to refer to the volcanic rock sequence forming the upper part of the Doublet Group. The unit is named after Willbob Lake (sheet 23O01), where typical outcrops are well exposed to the north and east of it (Frarey and Duffell, 1964). The rocks of the Willbob Formation have been mapped by Fahrig (1952, 1964), Frarey (1952, 1967), Donaldson (1966), Baragar (1967) and Dimroth (1972, 1978). SW of Deborah Lake (sheet 23P05), Girard (1989, 1995) described a lithological package consisting of amphibolitized basalt, iron formation and sulphidic schist. These rocks, previously assigned to the Laporte Group (now Laporte Supersuite), were reassigned to the Willbob Formation by Girard (1995). Wardle (1979, 1982) mapped volcanic rocks of the Willbob Formation on the Labrador side.
Description
The Willbob Formation is the largest unit of the Doublet Group in terms of volume. It consists mainly of massive or pillow tholeiitic basalt flows, pyroclastic rocks and glomerophyric or porphyritic basalt interstratified with tuff, mudstone, tuffaceous mudstone and pyritic mudstone layers. Iron formation and sulphide quartzofeldspathic schist layers are present locally. The Willbob Formation also includes medium to coarse-grained gabbroic rock lenses associated with mafic lavas (Fahrig, 1964; Donaldson, 1966; Baragar, 1967; Frarey, 1967; Dimroth, 1972, 1978). Dimroth (1972, 1978) points out that fine-grained massive or pillow basalts gradually change laterally or vertically to coarser-grained gabbros and that it is generally impossible to distinguish between extrusive and intrusive varieties.
According to Dimroth (1972, 1978), basalts of the Willbob Formation are lithologically similar to basalts of the Bacchus (Swampy Bay Group), Menihek (Ferriman Group) and Thompson Lake formations. However, they are distinguished from these lavas by their essentially pillow nature (Baragar, 1967; Frarey, 1967; Dimroth, 1972, 1978; Wardle and Bailey, 1981). According to Dimroth (1972, 1978), colour variations of Willbob Formation basalts suggest greater compositional variations compared to Bacchus Formation basalts. Willbob glomerophyric basalt is not recognized in the other formations, except locally in the upper part of the Menihek Formation (Baragar, 1967; Dimroth, 1972, 1978). Basalts of the Willbob Formation are also distinguished by their more variable geochemical composition. In particular, the MgO content varies from 4.8 to 14.3% and the TiO2 content from 0.6 to 1.7% (Rohon, 1989; Girard, 1995; Clark and Wares, 2004). The presence of lavas with composition corresponding to that of komatiitic basalt has been noted by Girard (1995).
The majority of Willbob Formation basalts are tholeiitic, depleted in potassium, and have a composition characteristic of oceanic rift basalts (MORB type), transitional to intraplate basalts (Baragar, 1960; Rohon et al., 1988; Rohon, 1989; St. Seymour et al., 1991; Skulski et al., 1993; Girard, 1995; Clark and Wares, 2004). Willbob Formation basalts are interpreted as the result of rifting of the second volcano-sedimentary cycle’s sedimentary sequence in central Labrador Trough (Wardle and Bailey, 1981; Skulski et al., 1993). Rocks of the Willbob Formation are generally metamorphosed to the greenschist facies. They reach the lower amphibolite facies east of the Lac Keato Lake and Lac Elsie faults, SW of Deborah Lake (Dimroth and Dressler, 1978; Fraser et al., 1978; Girard, 1995). In this area, Girard (1995) arbitrarily aligns the boundary between the two facies with the Lac Du Chien Fault.
Volcanic rocks of the Willbob Formation are generally unmineralized, except in the vicinity of mafic-ultramafic sills of the Gerido Intrusive Suite. Abundant copper, nickel and PGE mineralization including Lac Retty (Lac Bleu), Lac Retty (Lac Pogo), Lac Retty (Centre) and Lac de la Chance, among others, are associated with a peridotite-gabbro sill intruding at the contact between the Thompson Lake and Willbob formations (Clark and Wares, 2004).
Willbob Formation, Undivided (pPwl): Massive or Pillow, Locally Porphyritic, Tholeiitic Basalt with Flow Breccia, Pyroclastic Breccia, Tuff, Fine-Grained Sedimentary Rocks and Associated Gabbroic Rocks
This undivided unit consists mainly of massive or pillow, locally porphyritic tholeiitic basalts associated with flow breccias, pyroclastic breccias, tuffs, fine-grained sedimentary rocks and associated gabbroic rocks (Frarey, 1967).
Willbob Formation 1 (pPwl1): Massive or Pillow Tholeiitic Basalt; May Include Mafic Pyroclastic Rocks
Unit pPwl1 consists of alternating massive or pillow tholeiitic basalt flows (Donaldson, 1966; Baragar, 1967; Fahrig, 1964; Frarey, 1967; Dimroth, 1972, 1978; Girard, 1995). These flows vary in thickness from 2 to ≥20 m. However, pillow basalt flows are predominant. Basalt is grey to black in fresh surface and light grey, green or buff in altered surface. The rock is fine grained to aphanitic, locally medium grained, aphyric, homogeneous and unfoliated. Pillows are joint and range in size from <1 m to >2 m. The longest pillows are commonly elongated. Pillows have a chloritic margin 1 to 3 cm thick. They are rarely amygdaloidal. Their polarity is usually indicated by a well-developed peduncle. Quartz chambers are commonly seen in the upper part of the pillows and are elongated parallel to the pillow margin. Cavities and interstices between the pillows are usually filled with quartz, calcite and chlorite. Hyaloclastic breccia is commonly observed at the base or top of the flows. It is mainly composed of pillow fragments (Dimroth, 1972, 1978). Massive flows in places display columnar joints with a diameter varying from 10 to 75 cm (Donaldson, 1966). In places, mafic pyroclastic rocks (tuff, flow breccia, block tuff) are interstratified with basalt flows (Fahrig, 1964; Donaldson, 1966; Frarey, 1967).
In thin sections, basalt is typically composed of intergrown actinolite, albite, chlorite, clinozoisite and sphene crystals. Augite is locally observed. Accessory minerals are quartz, leucoxene, biotite, calcite, magnetite and ilmenite (Fahrig, 1964; Donaldson, 1966; Baragar, 1967; Frarey, 1967).
Willbob Formation 2 (pPwl2): Glomerophyric or Porphyritic Tholeiitic Basalt
Unit pPwl2 consists of glomerophyric or porphyritic tholeiitic basalt. In the Ahr Lake area (sheet 23O10), these lavas form three layers ~100 to 500 m thick inserted in aphyric lavas of unit pPwl1. The two lower flows are mainly massive, while the upper flow is pillowed (Baragar, 1967). In the area SW of Deborah Lake (sheet 23P05), the unit is ~500 m thick. It comprises a massive flow 60 m thick at the base, which is overlain by pillow lavas (Girard, 1995). Fine to medium-grained lavas are dark green to greenish grey in fresh surface and light green in altered patina. They are characterized by a glomerophyric texture resulting from the presence of aggregates of altered plagioclase crystals forming creamy-white patches or spots. This texture gives a spotted appearance to the rock (Fahrig, 1964; Donaldson, 1966; Frarey, 1967; Baragar, 1967). Patches are irregular in shape and vary in diameter from 0.2 to 5 cm. Phenocrysts or aggregates of millimetric crystals of intergrown plagioclase are strongly altered to albite and epidote (clinozoisite). They generally constitute <1% of the rock, but can reach up to 10%. Massive lavas locally display columnar joints. Hyaloclastic rocks are sparse. Pillows are joint and centimetric to metric in size. Quartz and calcite fill cavities in the pillows and interstices between them. The imbrication of pillows indicates apparent flow directions towards the SE and NW (Girard, 1995).
Depending on the proportion of plagioclase glomerocrystals, unit pPwl2 basalt may locally resemble aphyric basalt of unit pPwl1 (Baragar, 1967; Girard, 1995). According to Girard (1995), basalt of unit pPwl2 is characterized by a MgO content of 5 to 6%, compared to >7% MgO for aphyric basalt. A few layers of glomerophyric gabbro and porphyritic gabbro of the Gerido Intrusive Suite (pPgrd3) are inserted in unit pPwl2 lavas in the Griffis Lake area.
In thin sections, basalt consists of albite, augite, actinolite, epidote, chlorite and iron oxide (Frarey, 1967; Girard, 1995). Albite forms euhedral microliths or rods, aggregates and randomly oriented phenocrysts. Accessory minerals consist of leucoxene, titanite, ilmenite and iron sulphides (Frarey, 1967). No primary texture is preserved in the matrix (Girard, 1995).
Willbob Formation 3 (pPwl3): Pyroclastic Breccia and Tuff
Unit pPwl3 consists mainly of pyroclastic breccia and tuff. It forms a strip up to 150 m thick over a distance of ~10 km SE of Retty Lake (Frarey, 1967). The rock contains fragments up to 20 cm in diameter. Some fragments are vesicular or amygdaloidal. Other outcrops reveal a very schistose fragmentary rock probably of pyroclastic origin. It is formed of strongly chloritized rounded fragments, 4 mm to 6 cm, in a matrix of chlorite and biotite. In thin sections, fragments are mainly composed of actinolite and pyroxene. Plagioclase is also present as small disseminated rods. Chlorite is observed around the fragments, in veinlets and replacing the matrix.
Willbob Formation 4 (pPwl4): Mudstone, Tuffaceous Mudstone and Pyritic Mudstone
Unit pPwl4 consists of mudstone, tuffaceous mudstone and pyritic mudstone. These rocks form layers or lenses inserted in unit pPwl1 lavas (Baragar, 1967; Dimroth, 1972, 1978). According to Baragar (1967), the thickness of the widest strip varies from 160 to 230 m; the total thickness of this unit does not exceed 500 m. Mudstone is black, graphitic and composed of a finely recrystallized matrix of quartz, plagioclase and white mica. Greenish grey tuffaceous mudstone is composed of actinolite, chlorite, epidote (zoisite) and sphene. In places, mudstone contains sufficient pyrite and pyrrhotite to form gossan (Baragar, 1967).
Willbob Formation 5 (pPwl5): Sulphide Facies Iron Formation (Boulder Trails)
Unit pPwl5 consists of sulphide facies iron formation. It occurs as boulder trails or metre-thick layers hosted in basalts of unit pPwl10 (Girard, 1995). North of Rond Lake, a sulphide facies iron formation layer can be traced for >500 m. Unit pPwl5 is associated with metric layers of silicate facies iron formation (pPwl6) and garnet schist (pPwl11). Iron formation blocks exhibit intense deformation in contrast to that observed in lavas of the area. According to Girard (1995), these boulder trails and abundant gossan indicate the presence of sulphide facies iron formation layers. These layers are associated with zones of schistose basalts, locally mineralized. Sulphide facies iron formation displays widespread rusty alteration. It is composed of 25 to 75% disseminated or semi-massive pyrrhotite as belts in graphitic schist. Minor amounts of pyrite and quartz are also present.
In thin sections, pyrrhotite occurs as granoblastic clusters, millimetric belts or subhedralc grains disseminated in a graphitic matrix. Pyrite forms centimetric veinlets or porphyroblasts, locally brecciated, in a matrix of pyrrhotite and microcrystalline graphite. Pyrite crystals are rounded, euhedral or having a microcrystalline texture. Pentlandite, sphalerite, chalcopyrite and trace magnetite form isolated grains and inclusions in pyrite or are associated with pyrrhotite. Granoblastic quartz (0-30%) and idioblastic muscovite (0-10%) occur as fragments or interstitial material between sulphides and define a durchbewegung texture. Quartz and muscovite are covered with microcrystalline graphite, which gives them a nearly opaque black colour. Accessory minerals are carbonate, epidote, magnesian chlorite, titanite and zircon. Cracks are filled with hematite and goethite (Girard, 1995).
Willbob Formation 6 (pPwl6): Silicate Facies Iron Formation
Unit pPwl6 consists of silicate facies iron formation. It forms a layer a few metres thick NW of Rond Lake (sheet 23P05) (Girard, 1995). The rock is banded and composed of a matrix of very fine quartz (30-60%), grunerite, pennite (chlorite), muscovite and disseminated graphite. Biotite porphyroblasts a few millimetres in diameter are scattered throughout the rock. Garnet, which accounts for up to 30% of the mode, forms irregularly distributed porphyroblasts (3-5 mm). In thin sections, grunerite is prismatic to acicular and disseminated in the matrix or in clusters of euhedral crystals. Garnet is altered to pennite. Opaque minerals consist of disseminated pyrrhotite and millimetric pyrite cubes. Pressure shadows border the various garnet, biotite and pyrite porphyroblasts (Girard, 1995).
Willbob Formation 7 (pPwl7): Magnesian Tholeiite
Unit pPwl7 is located east of Retty Lake where it forms a NW-SE strip extending SE for ~28 km. It consists of massive to pillowed lavas interstratified with hyaloclastic rocks. These lavas are light green to greyish, generally aphyric to locally microporphyritic. They contain clinopyroxene and plagioclase microphenocrysts. Lavas are altered to actinolite, chlorite, zoisite and albite, and contain disseminated pyrite. Pillows are rounded and joint with a minor amount of hyaloclastic interstitial material. They display well-developed radial and concentric fracturing. Quartz-filled cavities are commonly observed. Pillows have an asymmetric peduncle suggesting a flow component towards the NW. Hyaloclastic rocks form layers 1 to 10 m in thick. They contain pillow fragments (Girard, 1995).
The norm of unit pPwl7 lavas indicates that they are tholeiites (normative clinopyroxene-orthopyroxene-plagioclase basalts containing <5% normative olivine or quartz) as well as olivine tholeiites (normative clinopyroxene-orthopyroxene-plagioclase-olivine basalts). These lavas are characterized by a high magnesium content (10-15% MgO), indicating a magnesian or olivine tholeiite composition (Girard, 1995). Relict microspinifex textures were noted by Girard (1995). These consist of clinopyroxene crystals in a matrix of devitrified material.
Willbob Formation 8 (pPwl8): Massive Tholeiite
Unit pPwl8 consists of a flow or succession of flows of massive tholeiite, totalling 150 m in apparent thickness and laterally continuous for >3 km (Girard, 1995). These lavas are overlying magnesian tholeiite of unit pPwl7. They are aphyric and have a granular to ophitic texture. Girard (1995) noted several cycles of grain size reduction. Each cycle is ~30 m thick. The first 20 m at the base have a grain size generally >1 mm and are characterized by a massive, homogeneous and slightly fractured texture. In the upper 10 m of each cycle, the grain size decreases until it becomes aphanitic. The rock exhibit columnar joints 10 cm to 2 m in diameter. The joints are oriented perpendicular to the surface of the flow. Radially growing columns are also observed. In places, rare metric lenses of hyaloclastic rocks and pillows are noted. Relics of sutured pillows at the top of the flow can be recognized. According to Girard (1995), this unit could represent either a sequence of individual massive flows superimposed on each other, or a single flow formed by several magma injections.
Willbob Formation 9 (pPwl9): Komatiitic Basalt; Gabbro
Unit pPwl9 was recognized SW of Sixte Lake (sheet 23P05). It consists of massive komatiitic basalt flow 50 m thick, displaying magmatic differentiation from the base to the top (Girard, 1995). According to Girard (1995), this unit can be confused with ultramafic sills (Gerido Intrusive Suite) mapped over >15 km towards the NW (Frarey, 1967) and over 10 km towards the SE (Fahrig, 1964). It is also possible that these are separate flows at the same stratigraphic level. Unit pPwl9 is directly overlying magnesian tholeiites of unit pPwl7 and constitutes a continuous and easily recognizable marker layer (Girard, 1995).
At the base, the flow has a chilled margin a few millimetres in size consisting of devitrified material, followed by a few centimetres of aphanitic material. The lava and glass are composed of ~15% altered skeletal phenocrysts suggesting olivine crystals. The composition of the chilled margin is consistent with komatiitic basalt (13-17% MgO).
Upwards, above the chilled margin, the unit forms a differentiated sequence of massive, homogeneous, medium to coarse-grained gabbroic rocks that have a brown to dark green alteration patina and cumulate texture. The differentiated sequence consists of olivine gabbro (8-20 m thick) gradually changing (~10 m) to (normative) melagabbronorite, which is gradually replaced (<1 m) by (normative) olivine-orthopyroxene gabbro (≤5 m thick). The latter gradually changes to granular gabbro evolving to ophitic gabbro (thickness unknown). For a detailed description, see Girard (1995, p. 16).
In thin sections, olivine gabbro has a cumulate texture generally defined by olivine, clinopyroxene and orthopyroxene crystals (1-3 mm). The primary mineralogy is commonly altered to very pale fibrous amphibole (tremolite-actinolite), without preferential orientation. Amphibole replaces olivine or pyroxene grains in the cumulate, while the altered intercumulus phase is composed of amphibole, talc, ripidolite and zoisite. Anhedral opaque minerals are partially replaced by titanite and leucoxene. Melanogabbronorite consists of a cumulate of orthopyroxene and clinopyroxene grains (1-3 mm) with rare coarser orthopyroxene crystals (3-5 mm) interspersed throughout the cumulate. Olivine-orthopyroxene gabbro (normative) consists of a medium-grained (1-2 mm) clinopyroxene granular cumulate and an intercumulus phase composed of an opaque mineral, partially altered to titanite. The primary mineralogy is commonly altered to very pale fibrous amphibole (tremolite-actinolite) with minor amounts of zoisite and carbonate. Medium-grained (1 mm) granular gabbro is composed of intergrown plagioclase rods containing pyroxene grains. The rock is also altered to actinolite and zoisite. Ophitic gabbro is similar to granular gabbro. It is distinguished by well-developed and better-preserved plagioclase rods with interstitial clinopyroxene grains. Towards the top of the unit, the grain size gradually decreases to ≤1 mm.
Near the top of the flow, the lava is greenish grey, fine grained and has a buff-coloured altered patina. It is fractured into columns, the diameter of which decreases from 60 to 10 cm over a few metres, indicating rapid cooling. The top of the flow is formed of hyaloclastic breccias (6 m thick) dotted with pillow fragments. The composition of one of the fragments is similar to that of unit pPwl7 magnesian lavas and to the chilled margin at the base of the flow.
Willbob Formation 10 (pPwl10): Amphibolitized Tholeiitic Basalt
Unit pPwl10 consists of amphibolitized tholeiitic basalt. These rocks are in cartographic continuity with basalts of unit pPwl1 (Girard, 1995). Amphibolitized basalt is green, fine grained, homogeneous and slightly to strongly foliated. Joint pillows, megapillows and rare hyaloclastic rocks are locally preserved. All primary textures have been obliterated by deformation or metamorphism. In thin sections, metabasalt is characterized by a nematoblastic, locally blasto-ophitic texture. The rock is composed of ~70% acicular to blocky crystals of light to dark green or bluish amphibole in a fine matrix of plagioclase crystals (30%). Plagioclase is commonly clear and unaltered. Relics of a glomeroporphyric texture are locally preserved. Accessory minerals include sphene, biotite, epidote, carbonate and opaque minerals. The intensity of the green colour, the size of amphibole crystals, the clarity of plagioclase and the grain size increase towards the NE, simultaneously with the disappearance of epidote. According to Girard (1995), this change in metamorphic paragenesis is consistent with the disappearance of primary textures and the increase in foliation intensity towards the NE. The composition of unit pPwl10 metabasalt suggests an oceanic setting (Girard, 1995).
Willbob Formation 11 (pPwl11): Garnet Quartzofeldspathic Schist
Unit pPwl11 is located north of Kozela Lake, ~3 km SW of Deborah Lake (sheet 23P05). The unit forms a metric layer of biotite quartzofeldspathic schist containing traces of garnet, tourmaline and zoisite (Girard, 1995).
Willbob Formation 12 (pPwl12): Mylonitic Sulphide Schist
Unit pPwl12 is located at Kozela Lake, ~4 km SW of Deborah Lake (sheet 23P05). It consists of a metric layer of mylonitic sulphide schist containing 10 to 20% pyrite and pyrrhotite (Girard, 1995).
Thickness and distribution
The Willbob Formation belongs to the allochthonous Retty Lithotectonic Zone, as defined by Clark and Wares (2004). It is the easternmost stratigraphic unit in the central Labrador Trough. The Willbob Formation volcanic sequence forms a NW-SE strip that extends from latitude 56°N to André Lake (sheet 23I12) in Labrador, a distance of ~170 km. According to Dimroth (1972, 1978), the total thickness of the formation cannot be determined, given its summit position. It has been estimated at 5000 m (Baragar, 1967; Frarey, 1967; Rohon, 1989). At latitude 56° N, the known thickness of the formation exceeds 900 m (Dimroth, 1972, 1978).
Dating
A Paleoproterozoic age of 1885 ±67 Ma was obtained for basalts of this unit (Rohon et al., 1993).
| Unit | Sample | Isotopic System | Mineral | Crystallization Age (Ma) | (+) | (-) | Reference(s) |
| pPwl1 | Basalte Fm. de Willbob | Pb-Pb | Total rock | 1885 | 67 | 67 | Rohon et al., 1993 |
Stratigraphic Relationship(s)
The Willbob Formation forms the upper part of the Doublet Group. It is the uppermost stratigraphic unit of the volcano-sedimentary sequence of the central Labrador Trough (Dimroth, 1972, 1978). The Willbob Formation conformably overlies the Thompson Lake Formation (Baragar, 1967; Frarey, 1967). Baragar (1967) notes, however, that the contact is commonly obscured by sills or is not visible due to a lack of outcrops. The top of the unit has not been defined (Frarey, 1967; Dimroth, 1972, 1978). Basaltic rocks of the Willbob Formation are overthrusted to the east by metasedimentary rocks of the Laporte Supersuite. Basalts of the Willbob Formation have been correlated with those of the Hellancourt Formation (Koksoak Group) (1874 ±3 Ma; Rohon et al., 1993; Machado et al., 1997) and with the upper part of the Menihek Formation (Ferriman Group) (Findlay et al., 1995). Several mafic to ultramafic sills (Gerido intrusive suite) are intrusive in the Willbob Formation lavas.
Paleontology
Does not apply.
References
Publications Available Through SIGÉOM Examine
CLARK, T., WARES, R., 2004. SYNTHESE LITHOTECTONIQUE ET METALLOGENIQUE DE L’OROGENE DU NOUVEAU-QUEBEC (FOSSE DU LABRADOR). MRNFP; MM 2004-01, 182 pages, 1 plan.
DIMROTH, E., 1972. STRATIGRAPHY OF PART OF THE CENTRAL LABRADOR TROUGH. MRN; DP 154, 304 pages, 6 plans.
DIMROTH, E., 1978. Région de la fosse du Labrador entre les latitudes 54° 30′ et 56° 30′. MRN; RG 193, 417 pages, 16 plans.
GIRARD, R., 1989. GEOLOGIE DE LA REGION DU LAC DEBORAH – NOUVEAU-QUEBEC -. MRN; MB 89-37, 39 pages, 3 plans.
GIRARD, R., 1995. GEOLOGIE DE LA REGION DU LAC DEBORAH, TERRITOIRE-DU-NOUVEAU-QUEBEC. MRN; MB 95-20, 186 pages, 3 plans.
Other Publications
BARAGAR, W.R.A. 1960. Petrology of basaltic rocks in part of the Labrador Trough. Bulletin of the Geological Society of America; volume 71, pages 1589-1643.
BARAGAR, W.R.A. 1967. Wakuach Lake map-area, Quebec-Labrador (23O). Geological Survey of Canada; Memoir 344, 174 pages. https://doi.org/10.4095/123960
DIMROTH, E., DRESSLER, B. 1978. Metamorphism of the Labrador Trough. In Metamorphism in the Canadian Shield. Geological Survey of Canada; Paper 78-10, pages 215-236. https://doi.org/10.4095/104534
DONALDSON, J.A.1966. Marion Lake map-area, Quebec-Newfoundland (23I/13). Geological Survey of Canada; Memoir 338, 85 pages. https://doi.org/10.4095/123900
FAHRIG, W.F. 1952. Griffis Lake, territory of New Quebec, Quebec. Geological Survey of Canada; Paper 51-23, 1 page. https://doi.org/10.4095/108372
FAHRIG, W.F. 1964. Géologie, Griffis Lake, Nouveau-Québec. Geological Survey of Canada; Map 1121A. https://doi.org/10.4095/107788
FINDLAY, J.M., PARRISH, R.R., BIRKETT, T., WATANABE D.H. 1995. U-Pb ages from the Nimish Formation and Montagnais glomeroporphyritic gabbro of the central New Québec Orogen, Canada. Canadian Journal of Earth Sciences; volume 32, pages 1208-1220. https://doi.org/10.1139/e95-099
FRAREY, M.J. 1952. Preliminary map Willbob Lake, Quebec and Newfoundland. Geological Survey of Canada; Paper 52-16, 10 pages. https://doi.org/10.4095/124122
FRAREY, M.J. 1967. Willbob Lake and Thompson Lake map-areas, Quebec and Newfoundland (23 O/1 and 23 O/8). Geological Survey of Canada; Memoir 348, 73 pages. https://doi.org/10.4095/123896
FRAREY, M.J., DUFFELL, S. 1964. Revised stratigraphic nomenclature for the central part of the Labrador Trough. Geological Survey of Canada; Paper 64-25, 13 pages. https://doi.org/10.4095/123909
FRASER, J.A., HEYWOOD, W.W., MAZURSKI, M.A. 1978. Carte métamorphique du Bouclier Canadien. Geological Survey of Canada; Map 1475A. https://doi.org/10.4095/133909
HARRISON, J.M. 1952. The Quebec-Labrador iron belt, Quebec and Newfoundland. Geological Survey of Canada;Paper 52-20, 21 pages. https://doi.org/10.4095/123923
LE GALLAIS, C.J., LAVOIE, S. 1982. Basin evolution of the Lower Proterozoic Kaniapiskau Supergroup, central Labrador Miogeocline (Trough), Quebec. Bulletin of Canadian Petroleum Geology; volume 30, pages 150-166. https://doi.org/10.35767/gscpgbull.30.2.150
MACHADO, N., CLARK, T., DAVID, J., GOULET, N. 1997. U-Pb ages for magmatism and deformation in the New Quebec Orogen. Canadian Journal of Earth Sciences; Volume 34, pages 716-723. https://doi.org/10.1139/e17-058
ROHON, M.-L. 1989. Magmatisme protérozoïque et indices de Cu-Ni sulfurés (+ EGP) dans la Fosse du Labrador (Québec, Canada) entre les lacs Retty et Low. Université Pierre et Marie Curie, Paris VI; Doctoral thesis, 333 pages. http://www.theses.fr/1989PA066428
ROHON, M.-L., BESSON, M., CLARK, T., JORON, J.L., OHNENSTETTER, D., ROGER, G., TREUIL, M., VIDAL, P. 1988. Indices de Cu-Ni sulfurés liés au magmatisme mafique et ultramafique protérozoïque dans la Fosse du Labrador (Québec; Canada). In Gisements métallifères dans leur contexte géologique (Johan, Z. et Ohnenstetter, D., éditeurs). Documents du B.R.GM.; Numéro 158, pages 247-284.
ROHON, M.-L., VIALETTE, Y., CLARK, T., ROGER, G., OHNENSTETTER, D., VIDAL, P. 1993. Aphebian mafic-ultramafic magmatism in the Labrador Trough (New Quebec): its age and the nature of its mantle source. Canadian Journal of Earth Sciences; volume 30, pages 1582-1593. https://doi.org/10.1139/e93-136
SKULSKI, T., WARES, R.P., SMITH, A.D. 1993. Early Proterozoic (1.88-1.87) tholeiitic magmatism in the New Québec Orogen. Canadian Journal of Earth Sciences; volume 30, pages 1505-1520. http://doi.org/10.1139/e93-129
ST. SEYMOUR, K., KIDDIE, A., WARES, R. 1991. Basalts and gabbros of the Labrador Trough: remnants of a Proterozoic failed ocean? Neues Jahrbuch fuer Mineralogie, Monatshefte; Hefte 6, pages 271-280.
WARDLE, R.J. 1979. Geology of the eastern margin of the Labrador Trough. Department of Mines and Energy, Government of Newfoundland and Labrador; Report 78-9, 22 pages. https://gis.geosurv.gov.nl.ca/geofilePDFS/WBox040/LAB_0415.pdf
WARDLE, R.J. 1982. Geology of the south-central Labrador Trough. Government of Newfoundland and Labrador, Department of Mines and Energy, Mineral Development Division, Map 82-005.
WARDLE, R.J., BAILEY, D.G. 1981. Early Proterozoic sequences in Labrador. In Proterozoic basins of Canada (F.H.A. Campbell, editor). Geological Survey of Canada; Paper 81-10, pages 331-359. https://doi.org/10.4095/124192
Suggested Citation
Ministère de l’Énergie et des Ressources naturelles (MERN). Willbob Formation. Quebec Stratigraphic Lexicon. https://gq.mines.gouv.qc.ca/lexique-stratigraphique/province-de-churchill/formation-de-willbob_en [accessed on Day Month Year].
Contributors
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First publication |
Charles St-Hilaire, GIT, M.Sc. charles.st-hilaire@mern.gouv.qc.ca; Thomas Clark, P. Geo., Ph.D. (redaction) Mehdi A. Guemache, P. Geo., Ph.D. (coordination); Claude Dion, Eng., M.Sc. (critical review); Simon Auclair, P. Geo., M.Sc. (editing); Céline Dupuis, P. Geo., Ph.D. (English version); Ricardo Escobar Moran (HTML editing). |