Brezden Lake Syenite Introduction Burntwood Lake Alkali-Feldspar

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1928 T. Martins

Introduction What is new? Interactive pop-up map allows accessing documents for The Manitoba Geological Survey (MGS) initiated a project to re-visit a number of rare metal occurrences throughout the Province, the results of free download by clicking in each occurrence on the map which have been published in several reports of activities (e.g. Martins et al., 2011, 2012). The goal of this project is to characterize and evaluate the A summary of this project’s results will be published in a web-based format. This compilation aims to provide uniformly organized, concise rare metal potential of new and historical occurrences in the Province. and up-to-date information on rare metal occurrences in the Province of Manitoba. For each location, the report includes an exploration This is an ongoing research project, in which a summary of the results are being published in a web-based format. The website will have a summary, descriptions of the geological setting, mineralization and summary report for each rare metals occurrence, with the final objective of building a geoscientific database that can be used by the mineral geology of the occurrence, geochemical data, and pertinent exploration industry, as well as a technical database for use by local governments in resource evaluations, land use planning and regional references. Churchill development programs. Hudson Trans-Hudson orogen Bay Two examples of areas with rare metal potential are shown below, accompanied by outcrop photographs; followed by a brief presentation of the Introduction page of the rare metals website website format. Lynn Lake Hudson Bay Basin

Burntwood Lake alkali-feldspar syenite Thompson Kisseynew domain Rare Metals in Manitoba Medium-grained pink to beige syenite, Red syenite, one of the main syenite Example of irregular layering in pink Apatite- and clinopyroxene-rich red click the map to enlarge This compilation aims to provide uniformly organized, summarized and up- + with pyroxene and titanite as the main phases syenite syenite (appatite appears chalky white) to-date information on rare metal occurrences in the Province of Manitoba. Churchill Hudson The accompanying summary reports represent a geoscientific database Trans-Hudson orogen Bay maphic mineral phases that can be used by the mineral exploration industry, as well as a technical Oxford-Stull domain database for use by local governments in resource evaluations, land use Flin Flon planning and regional development programs.

Lynn Lake Most geochemical data was obtained from site visits by the Manitoba Hudson Bay Geological Survey (MGS). Also included are data from assessment files Basin and external authors for locations where MGS did not collect samples or where work was developed in collaboration with external authors. Thompson Kisseynew domain Superior Flin Flon Oxford-Stull domain Each report covers a specific location identified as having rare province Legend metal potential and summarises: Phanerozoic Superior Lake  province Legend Cenozoic sedimentary rocks exploration summary (where available) Phanerozoic Lake Cenozoic sedimentary rocks Winnipeg Mesozoic sedimentary rocks Winnipeg Mesozoic sedimentary rocks  geological setting Paleozoic sedimentary rocks Precambrian Paleozoic sedimentary rocks Mafic-ultramafic intrusive rocks Proterozoic granite and gneiss Western Canada  mineralization and geology of the occurrence Archean granite and gneiss Precambrian Sedimentary Basin Metagreywacke Metasedimentary rocks Mafic-ultramafic intrusive rocks  geochemical data Mafic-felsic metavolcanic rocks Proterozoic granite and gneiss Bird River domain +  pertinent references Western Canada Archean granite and gneiss Brandon Winnipeg Current producerPast producerDeposit/occurrence Metagreywacke Rare-metals + Sedimentary Basin For free downloads of each rare metal occurrence click Metasedimentary rocks on the map or select from the list below: Metasomatic, mafic-rich vein Fluorite (Fl)-bearing quartz-syenite The Burntwood Lake alkali-feldpsar syenite is located in the northwest arm of 0 100 200 kilometres Mafic-felsic metavolcanic rocks Burntwood Lake and is hosted by Burntwood Group metasedimentary rocks of the Burntwood Lake

Kisseynew Domain and peraluminous granite. Brezden Lake Bird River domain + Cinder Lake The syenite forms a heterogeneous intrusion that is modally and texturally Eden Lake Brandon diverse. The heterogeneity appears to be the result of a combination of crystal South Bay Winnipeg Current producerPast producerDeposit/occurrence Rare-metals + fractionation, metasomatism, and possibly contamination. A recessively weathered Fl Brezden Lake synenite Th-enriched vein was located along with discontinuous bands of massive apatite Carbonatite dyke intruding syenite at Eden Lake 0 100 200 which are enriched in both rare-earth elements and Th. The rocks of the Burntwood This compilation is intended to be an active online document that can be updated as new information becomes available. Additional information may be obtained Lake alkali-feldapr syenite bear many mineralogical, textural, and geochemical by contacting the author or the Director of the MGS. kilometres similarities to the carbonatite-hosting syenite complex at Eden Lake, a target of rare- earth element exploration.

Examples of documents that can be downloaded for each rare metal occurrence Brezden Lake syenite

lo lo eo gic eo gic Medium-grained biotite syenite with g a g a Laye pegmatite, cutting Metasomatic phase of the syenite a l a l b s b s o u o u

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Brezden Lake intrusive complex v South Bay pegmatites

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MGS a MGS y y m cm-size clots October 2015 m 1928 1928 Geochemistry Trace element diagrams indicate that the This report summarizes geoscientific knowledge on Manitoba The complete dataset for of whole-rock major and pegmatites are all very similar in terms of their trace occurrences with Rare Metal potential. This document can be trace-element compositions for the pegmatites from element composition (Figure 4 a-g), although the used by the mineral exploration industry, local governments in beryl-columbite pegmatites have slightly higher Nb, resource evaluations, land use planning and regional at South Bay can be found are available as a Data development programs. Updates to this document will occur as Repository Item (DRI2014001; Martins, 2014a). The Ta, Sr and Be. Geochemical ratios can be used to new information becomes available. samples are considered representative of the whole measure fractionation in a pegmatite (e.g. K/Rb, Available from http://www.manitoba.ca/minerals rock geochemistry because these bodies pegmatites K/Cs, Mg/Li) indicate that the pegmatite bodies at have relatively simple mineralogy, are not complexly South Bay are not very fractionated, as reflected by a • UTM: 336590E, 6218008N zoned, and large bulk samples (~10-15 Kg) were number of geochemical indicators: e.g. K/Rb= 83.32- • Area: Brezden Lake; west of Russell Lake; northern obtained to overcome the challenge of grain size. The 152.96, Mg/Li= 2.74-45.23, Rb/Cs= 65.00-320.00. flank of the Kisseynew domain studied pegmatite bodies are all granitic pegmatites. The beryl-columbite pegmatites can be further • NTS: 64C4 1000 1000 • Access: via floatplane classified as belonging to the rare-element (REL) class, beryl type, beryl-columbite subtype 100 100 Syenite with m-scale Introduction (classification scheme of Černý and Ercit, 2005). All pegmatite types are peraluminous (Figure 2) K/Rb

with Alumina Saturation Index (ASI=Al O /(CaO + K/Rb There is no record of exploration of the Brezden Lake 2 3 10 10 concentration of mafic minerals Na O + K O) ranging from 1.46 to 1.76. intrusive complex. The area was mapped at a regional 2 2 3 a b scale by the Manitoba Geological Survey (MGS) in the Metaluminous Peraluminous 1 1 1 10 100 1970s, and the complex was later mapped in detail by 1 10 100 Be Li McRitchie (1988) as a potential host for zirconium 1000 1000 mineralization. In 2012, the MGS carried out a 2 reconnaissance study focused on the rare earth 100 100 elements (REE) potential of the complex (Martins et al.,

2012a). K/Rb K/Rb

The Brezden Lake intrusive complex is a heterogeneous multi-phase intrusive body, identified as having the potential to host Al/(Na+K) 10 10 1 Peralkaline Quartz-feldspar-garnet c d rare metals and rare-earth-elements. It is located southwest of Lynn Lake where it is hosted by Burntwood Group Geological setting Layered pegmate 1 1 Beryl-Columbite 0.1 1 10 1 10 100 1000 The Brezden Lake intrusive complex is exposed over Cs Nb metasediments and peraluminous granitoids of the Kisseynew Domain. 0 1000 1000 a length of about 4 km and a width of about 0.8 km along 0.5 1.0 Al/(Ca+Na+K)1.5 2.0 the eastern side of Brezden Lake (Figure 1; Martins et al., Figure 2: ASI diagram for the different types of pegmatites 2012a). This intrusive complex intrudes turbiditic types described at south Bay. 100 100 metasedimentary rocks of the Burntwood group at the Figure 1: Geology map of the Brezden Lake intrusive K/Rb northern flank of the Kisseynew domain (KD), as complex with location of stations from the different authors K/Rb Localized metasomatism led to enrichment in rare-earth-elements. Carbonate was identified associated with the that worked in the area (from Martins et al., 2012a). Selected variation diagrams illustrate the 10 10 primarily identified by Lenton (1981), and very close to chemical compositions of the different types of the limit of the North Flank Kisseynew subdomain e f pegmatites at South Bay, and do not showing 1 1 metasomatized phases. Petrographic study revealed granoblastic calcite and calcite replacing other mineral phases. boundary defined by Zwanzig (2008). significant variation in terms of their major elements 0.1 1 10 100 1000 1 10 100 Ta Sr Two generations of isoclinal nappe-style folds (Figures 3a-d). 1000 The KD is a metasedimentary basin in the internal (D –D , 1820–1800 Ma; Zwanzig, 1999) were 18 0.07 Granoblastic calcite suggests equilibrium and could be derived from a carbonate fluid, whereas interstitial and replacing calcite 2 3 16 F i g u r e 4 : Tr a c e e l e m e n t zone of the Trans-Hudson Orogen. The tectonic setting of accompanied by the intrusion of peraluminous 0.06 14 100 discrimination diagrams (a-g) the Kisseynew basin continues to be a matter of debate: it granitoids (1820–1810 Ma; Kraus and Menard, 0.05 12 versus K/Rb for the different suggests non-equilibrium and possible remobilization of the carbonate. No carbonatite was found associated with the Brezden has variously been interpreted as a back-arc, intra-arc or 3 0.04 10

1997; White, 2005). The majority of the KD O K/Rb 2 types of pegmatite bodies in the

fore-arc basin (Ansdell et al., 1995; Zwanzig, 1997; Al 8 MgO 0.03 experienced low-pressure granulite-facies 10 South Bay area. (Symbols as 6 Zwanzig and Bailes, 2010). The KD is largely underlain metamorphic conditions of 750º ±50ºC and 5.5 ±1.0 0.02 Coarse-grained syenite with Lake intrusive complex but many aspects including mineralogy, textures and geochemistry are similar to the syenite that hosts 4 previous.) by turbiditic metagreywacke of the Burntwood group 0.01 g kbar (Gordon, 1989) following D2 (White, 2005). 2 b a 1 (Zwanzig, 1990), which was deposited between ca. 1860 0 0 Peak metamorphic conditions continued through D3. 1 10 100 1000 72 74 76 78 80 72 74 76 78 80 clinopyroxene, K-feldspar and titanite the carbonatite at Eden Lake. and 1840 Ma (Machado et al., 1999). Early folding and Ba SiO2 D SiO2r a f t thrusting (D ) occurred during sedimentation (1842–1835 1 Folding and faulting continued during D4 and D5 0.7 1.6

Ma; Machado et al., 1999; Zwanzig, 1999) and predated until after ca. 1790 Ma (Zwanzig, 1999). The rocks 0.6 1.4 The chondrite-normalized REE patterns (Figure 1.2 metamorphism in the KD. The D1 deformation phase was from the Burntwood Group at Brezden Lake were 0.5 5) for all the pegmatite types show are similar features

accompanied by intrusion of ca. 1840–1820 Ma 3 1 O and REE proﬁles. All pegmatite groups types are

exposed to lower temperature metamorphic 0.4 2 0.8 D r a f t CaO Fe calcalkaline plutons (Machado et al., 1999). conditions than Burntwood Group rocks in the 0.3 slightly HREE enriched with a moderately negative 0.6 central KD. Lenton (1981) identiﬁed at least one 0.2 Eu anomaly (chondrite-normalized La ~1.3-9.7, Yb 0.4 The youngest calcalkaline intrusions in the KD are (possibly two) major prograde metamorphic event 0.1 ~0.62-12.4). This is commonly observed in granitic References c 0.2 d represented by the enderbitic Touchbourne suite, which with metamorphic conditions in the range from 600º 0 0 pegmatites which are generally very REE depleted was intruded between ca. 1830 and 1820 Ma (Gordon et 72 74 76 78 80 72 74 76 78 80 (Černý, 2007). to 630ºC at 2.5 kbar. Rare Metals in Manitoba SiO2 SiO2 Rare Metals in Manitoba al., 1990; Machado et al., 1999), prior to the main Figure 3: Major element variations of Al, Mg, Ca and Fe Martins, T., Couëslan, C.G. and Böhm, C.O. 2011: The Burntwood Lake alkali-feldspar syenite revisited, west-central Manitoba (part of NTS 63N8); in Report of Activities 2011, Manitoba Innovation, Energy and Mines, Manitoba Geological tectonometamorphic event. oxides (wt.%) with Si (wt.%) (a-d). The data represent compositions from the several pegmatite types at South Survey, p. 79–85. Bay. (Symbols as previous.) Martins, T., Couëslan, C.G. and Böhm, C.O. 2012a: Rare metals scoping study of the Brezden Lake intrusive complex, western Manitoba (part of NTS 64C4); in Report of Activities 2012, Manitoba Innovation, Energy and Mines, Manitoba Geological Survey, p. 115–123.