Historical report by the British Columbia Geological Survey on carbonatites and related rocks. Ther report was completed by geologist Jennifer Pell who has spent several years studying rare metals in British Columbia's Rocky Mountain Rare Metal Belt.

1. Ministry o Eneqy, Mines and Petroleum Resources
f
CARBONATITES AND SYENITE GNE,ISS
COMPLEXES IN METAMORPH0SE:D
PRECAMBRIAN TO EARLYCAMIBR1:A:N
STRATA. OMINECA BELT
MANSON CREEK AREA (93N/9) been deformed and metamorphosedto lower amphibolite
facies. The hostrocks include psammitic semipelitic mica
to
Syenite, monzonite and calmnatite occur together on schists,micaceousquartzitesandsomemarbleswhichstrike
both the Lonnie (Granite Creek) andVergil (Brent) claims. southeasterly (15Oo-17O0)and dip steeply to the southwest
The two showings arelocated 3 kilometres apart, approxi- (7Oo-8O0)on average.
mately 8 kilometres east of the placer mining village of The various rock units within each intrusive zone are
Manson Creek, 230 kilometres northwest of Prince George. distributed in interfingering lenses (Hankinson, 1958;
Exposures are in trenches, between loo0 and 1.100metres Rowe, 1958; Halleran, 1980). The Lonniecarbonatite is up
elevation, on wooded slopes; elsewhere outcrop is sparse. to 50 metres thick and traceable for nearly 500 metres (Fig-
TheLonniecarbonatitecanbereachedbyanoldroad,which ure 27);theVergil showing is approximately30 mftres thick
is passable by four-wheel-drivevehicle to within 1 kilome- and canbe traced for a few hundred metres.The effects of
tre of the showing (latitude 55”40’45”N, longitude alkali metasomatism(fenitization) can be detected for a few
124°23’15”W). The Vergil showing,approximately5.5 kil- tens of metres beyond the intrusions.
ometres from the nearest road, is accessible by helicopter or
on foot (latitude 55”42’45”N,longitude 124°25’15”W). CARBONATITES
At both showings, theintrusive rocks occurin single, W o varieties of carbonatite are present within the Lon-
northwest-trending, sill-like sheets within uppermost Pre- nie complex: one is aegirine sovite in which the principal
Cambrian metasedimentary rocks the Wolverine Complex
of components are calcite, microcline, perthite and aegirine;
(Lang ef al., 1946). Both intrusive rocks and hostrocks have the other is biotite sovite, comprising calcite, b.iotite and
~~ ~~~~
_-
~~~~~
LEGEND
S y e n i t em o n z o n i t em o n z a d i o r i t e
, ,
Aegerine-amphiboleenite
f
Mylonitized
biotite
sovite
Biotite
sovite
Aegerine sovite
lnferiayered ovife nd emipelitic chisl
s a s s
Wolverine omplex iotite sammit?,
C b p
s e m i D e l i t i c c h i s tm i n o a u a r t z i l e
s , r
Figure 21. Geological map of the Lonnie (GraniteCreek) carbonatite complex (contours metric), after Rowe,
1958
Bulletin 88 37

2. usually plagioclase. Only biotite sovite occurs at the Vergil tain accessory muscovite, biotite, calcite and apntite.
showing. Both the biotite and aegirine sovites are variably Nepheline syenite is also locally present and contains: sig-
foliated and containapatite (up to 20%). magnetite and py- nificant amounts of zircon (3-15%).
rochlore as accessory minerals. The biotite sovite may also
contain zircon; columbite, ilmenorutile and ilmenite have FENZTES
also been reported (Hankinson, 1958). At the Lonnie show-
ing, aegirine sovite occurs along the southwestern margin Pods andlayers of fenite occur within both the Lonnie
of the complex and biotite sovite along the northwestern and Vergil intrusive complexes. The fenite is medium to
dark green in colour and rusty weathering. It consists of
margin (Figure 27). The biotite sovite is variably myloni- aegirine and sodic amphibole (Plate 14) with microcline.
tized, with the most intense shearing near the contact with
the country rocks. Enrichmentin zircon, pyrochlore, colum- plagioclase and calcite in varying amounts. The amphibole
bite, pyrite and pyrrhotite has been noted nearthe contacts is strongly pleochroic, x -turquoise, y - colourless, z - PNS-
of the sovites with syenites (Hankinson, 1958). sian blue, with colour strongest at the rims. It issimilar to
the amphibole at the Aley complex, which has been itlenti-
fied as magnesio-arfvedsonite(Miider, 1986, 1987). ‘Trace
SILICATE PHASES constituents in fenites include pyrochlore, magnetite and
Feldspathic intrusive rocks, monzodiorite, monzonite zircon.
and syenite, outcrop as lenticular masses separating the car- The hosting psammitic and semipelitic schists arc rec-
bonatite units (Figure 27). These intrusive rocks consist of ognizably fenitized for a fewtens of metres beyond the in-
potassium feldspar (orthoclase or microcline) and plagio- trusive contacts. Microcline, plagioclase and quartz are
clase in varying proportions; plagioclase greatly exceeds major constituents, with aegiriue and arfvedsonite dissemi-
potassium feldspar in the monzodiorites,in the monzonites nated throughout, presumably replacing the original mafic
the proportions approach equality and potash feldspar silicate minerals. Biotite is present in trace amounts only.
greatly exceeds plagioclase in the syenites. All phases con- Calcite, apatite, magnetite and zircon may be present and
Plate 14. Blue pleochroic amphibole (rnagnesio-arfvedsonite)and finer grained aegirine (light green) in ultrafenite, Lonnie area.
Long
dimension of photomicrograph is2.5 millimetres, (colourpkoto,page 135).
38 Geological Survey €!ranch

3. ~~~ ~ ~~~ ~ ~~~ ~~ ~~ ~ ~
coarse-grained arfvedsonite, magnetite andfeldspar segre-
gations are developed locally.
GEOCHEMISTRY
Carbonatites in the Manson Creek area are all true
sovites, no magnesio- or ferrocarbonatites were observed
(Figure 28; Table7. Aegirine sovites are depleted in silica
)
and aluminum and enriched strontium, relative to biotite
in
sovites. Fenites are notably enriched in iron and sodium,
relative to other lithologies (Figure 29; Table 7. With in-
)
creasing degree of fenitization, that is from recognizable
metasedimentsto ultrafenite, the rocks exhibit a systematic
increase in iron and alkalis relative to calcium (Figure 30a)
and fenitization appears to be a combination of 'typical'
iron-magnesium andalkali fenitization trends. The fenites,
even ultrafenites (aegirine and arfvedsonite rich) are en-
riched in sodium relative to typical pyroxene-amphibole
fenites (Figure 30b). J
Syenitic rocks are quite vaned in composition (Figures Figure 28. CaO-MgO-Fez03t+MnO carbonatite pht, Lonnie
29and31;Table7)but,onaverage,plotwithinthemiaskitic complex.
TABLE 7
CHEMICAL ANALYSES OF ALKALINE ROCKS, MANSON CREEK AREA
"
~ ~~~ ~ ~ ~~ ~~~ ~
Syenites and contact syenites Fenite
7 6 8 9 10 141113 12
15 15
-
Si02 1.70 12.70 12.00
13.70 7.81 ' 4 0 56.70 53.77 36.44
1.0 51.09 32.88 44.5035.9638.8273.1557.82
Ti02 0.02
0.67
0.71
0.01 0.08 0.03 0.02 0.530.03
0.40
0.20 0.66
0.38
0.28 0 6 0.83
.4
3.653.26 7.46 0.367.573.06 16.70 15.38 12.14
2.4811.61A12036.792.2214.30 14.93 11.74
Fe203T 1.40
6.21 5.70 0.37 5.39
1.44 0.57
0.80 4.84
0.59 2.63 19.60 6.91 18.63
11.66 4.52
0.59
0.37 0.24 0.16 0.28 0.23 0.11 0.26
0.15
0.25
0.37 0.24 0.30
0.34
0.24
0.115
0.31 2.20 1.85 0.60
1.21
0.17 0.12 1.73
0.18
1.36
1.15
2.48
2.11
1.13
1.11 2.112
CaO 52.90 36.10 43.72 6.09 9.78 20.19
36.60 48.29 16.30 8.85 23.12 10.90 14.56 0.34
24.21 1.34
Na20 0.44 1.21 0.99 5.57 2.46 5.79 10.33
3.48 4.97 5.37 10.30 5.55
0.36 6.94 3.53 3.99
0.12 2.45 2.04 0.49 0.19 5.36 5.84 1.89
4.82
1.50
4.43 0.24 0.50
1.14 1.61 0.ZI
4.417.48 17.89
7.9817.47 6.56 18.06 0.46
11.48 0.77
0.61
1.05 1.29 1.65
0.34 0.76
0.71
1.13
0.05 0.04
99.27 98.8298.7498.24 99.8985.9399.2799.5599.5998.13
ppm
Ni <2 <2 <2 2 9 8 4 4 4 33
7 28
5 65 5
Cr e20 7 9 <20 e 20 36 52 1415 < 20 <20 153 24 34
77 6:
7 8 co
10 10 7 5 3 12 11 9 9 < 5 2 8 3 8 3 1
Sr 12009 6643 7959
6907 8780 4125 1110 1940 3143 2303
5360 5095
6738 233
1506 3:
Ba 9861097662
14551926 26341191
22302479
1321215
27522084
387
129 4:
Zr 76 127 10363
154
77
385
2030 1062 170
298
322
756 641 198
2324
311
Nb < 5 78306 2 43 1444 358
8831589
1274884
2465 19 253
387 17
56 33 44 78 46 77 Y
66 54 69 62 53 16 19 36 YO 11
La 247 345
43 371
135347
398
401 222 265 88 254 102 1 0 173
9 22
Ce 600 172 426 483
130 392 107 673
325 470 286
176 398 660
741 31
Nd 245
179 206 102 35 56
Yb 6.27.7 5.2 3.5 3.8 2.1
sc 30 17 4.8 23 16.820.5 7.24.1 37
46 16.318.5 8.4 41 11.2
31
Ta c2 2 4 < 2 11 c 2 37 17 25 9 3 < 2 <2 <2 8 <2
Th <<6
<66
<66
< 25 28 17 8 < 6 18 6 8 65 244 19
I-LA179C oegirine sovite, Lonnieclaim 12- ultrafenire,
LA174B Lonnie claim
2-01242B biotite sovite, Vergil
claim 13- ultmfenite,
LA197E Lonnie claim
3-011184 biotite sovite,Lonnie claim 14-
LAl79E banded, calcareous
fenite, Lonnie claim
4-LA242C white. massive sovite, Vergil
claim IS- l.4178
fenitired
metasediment with carbonaiite
5-LA252 carbowrite breccia, Vergil claim veinle:, Lonnie claims
6-l.41978 syenite, Lonnie claim 16- l.41740fenirired
mefasediment, Lonnie claim
74.42408 syenite, Vergil claim Samples 1,2,3.6,7,12%- majorelementsnmlyred
8-01250 syenitic breccia, Vergilclaim by ICAP; trace elements by XRF;
9-LAl74A marsive syenite, Lonnie claim REE by INAA at Bondar-Clegg.
IO-LA248 mixed syenitdcarbonatite, Vergil claim Sampbs4, 5,8,9,10,11.13,14,15,16,-
II-LA197D carbonatitdsyenife contact, Lonnie claim Major and tmce elements byXRF.
Bulletin 88 39

4. %% carbonatites
A fenite
0 syenite
trend
Creek
"normal.. fe-Mg fenite
trem
pyroxene
amphibod<
fenites
Figure 29. Majorelementternary plots, MansonCreekarea Figure 30. Ternary fenite plots, Manson Creek area carbsnatitc
carbonatite complexes. complexes.
syenite field (Figure 31). These rocksmay contain signifi- GEOCHRONOLOGY
cant amounts of zirconium, upto 1.23%, and are enriched The Lonnie and Vergil carbonatites contain zircm, p y
in barium and niobium relative to other igneous andmeta- rochlore and other uranium-bearing minerals arc: ame--
that
somatic rocks the area. Niobium pentoxide
in values of be- nable to uranium-lead geochronoIogy. Zircons from
tween 0.1 and 0.3% have been reported from the Lonnie samples collected from the Lonnie andVergil carbonatite-
showing. Azone in the centre of the property averages 0.3% syenite complexes are generally large crystals that are
NbzOs across a width of 7.6 metres and a length of 240 equant and clear. Analyses fromthese samples are ciscor-
metres (Vaillancourt and Payne, 1979). dant, but indicate a uranium-lead age of 340 Ma anc. lead..
Rare-earth element abundancesrocks in the Manson
of lead ages of 351 to 365 Ma (Appendix which is similar
2),
Creek area are uniformly low, compared to those at Aley, to the age of the zircons from the Ice River complexin the
Kechika River and Rock Canyon Creek (Appendix and, 1) Rocky Mountains. Preliminary uranium-lead syste~natic!i
as indicated by the shallow slope on chondrite-nomalized do not yield precise ages for these zircons, but do suggest
plots, the light rare-earth enrichment is not as marked (Fig- that the Lonnie and Vergil carbonatites were emplaced iu
ure 32). Late Devonian early Mississippiantime.
to
__
40 Geological Survey .3ranch

5. Ministry of Energy, Mines and Petmleum Resources
CHONDRITE-NORMALIZED REE PLOl
average Lonnie
syenite 105 Lonnie & V e r g iS h o w i n g s
l
X overagemonzonite
- Monson C r e e k r e a
A
.
.
.
Carbonatite
A Fanile
104 -
D syenite
.
.
.
.
.
Subalkaline basalt Alkali
rocks
mmrr
30.00 40.00 50.00 60.00 70.01
Si02
Agpaitic 1
!O.OO- syenite La Ce Pr Nd Sm Eu Tb Dy Ho 'lm Yb LI
family
Rare-Earth lements
E
Mlaskitlc __
syenite
family Figure 32. Chondrite-normalized REE plots, Lonnie and Vergil
5.00 showings, Manson creek area.
Nephelinite
family The alkalic rocks are hosted by high-grade metarnor-
phic rocks assigned to the Wolverine complex, 0' ; probable
0.00- late Proterozoic age, and are exposed in a 5 hy 10kilometre
area, south andeast of the Manson River, in the Wolverine
Ranges of the Omineca Mountains. Within this arxa,num-
a
- 0 ber of discrete alkalic dikes and dike swarms arepresent,
5.00-
."
. Subalkaline
associated with alkalic pegmatite dikes or segreg&ions,in-
rocks trusive breccias and large metasomatic alteration halos
U " (fenites); unfoliated, fine-grained quartz morzonite to
0.00 quartz syenite intrusions are also present, but may or may
30.00 40.00 50.00 60.00 70.0 not berelated to the alkaline syenites. The relationship be-
Si07
tween the intrusion of alkaline rocks andmetamorphism is
Figure 31. Alkali-silica and agpaitic index plots, Lonnie complex unclear from available literature.
the
silicate rocks. (A) Agpiatic index plot - Lonnie complex silicate The area is accessible from good logging roads run
that
rocks; (B) Lonnie - alkali vs silica diagram. along the west side of WillistonLake fromWindy Point,at
the south tip of the lake, to Manson Creek.
MOUNT BISSON - MUNROE CREEK
AREA (93N/9; 930/5,12) ALKALIC DIKE ROCKS
Alkalic syenites are exposed in the Mount Bisson - Three types of syenite dikes are present in the Mount
Munroe Creekarea of north-central British Columbia (lati- Bisson - Munroe Creek area: the fzst rich in alkali feldspar;
the second containing abundant aegirine-augitc:; and the
tude 55'31'00"N, longitude 124"00'00'W), 64 kilometres third a suite of rare-earthelement enriched dikes which con-
northwest of the town of Mackenzie (Figure 1). They were tain allanite as the main rare-earth mineral. The alkali ield-
discovered in 1986 and 1987 A.A.D. Halleran.The min-
by spar dikes contain 90% potassium feldspar rimmed with
eralogy andfield relationships were describedby Halleran plagioclase, and 10% mafic minerals, predominantly aegir-
(1988) andHalleran andRussel1 (1990) and summarized
are ine-augite. The aegirine-augite dikes contain, 011 average,
from these works. 40 to 60% aegirine-augite grains, up to 1.5 centimetres
"
Bulletin 88 41

6. across, 35% perthite, 3% sphene with rare allanite inclu- gioclase (Anzz-uI), potassium feldspar, biotite, chloritz and
sions, 1%apatite and traces of allanite, magnetite, chalco- traces of magnetite, allanite, apatite and zircon.
pyrite and malachite. These dikes are banded, with mafic
the
minerals concentratedin thin, discrete zones. The allanitic GEOCHEMISTRY
dikes are also rich in aegirine-augite: they consist of ap-
proximately 80% aegirine-augite, 8% potassium feldspar,
5% apatite, 3% allanite and 2%sphene, withaccessory cal-
cite and biotite.
PEGMATITES
Two types of alkalic pegmatites are described by Hal-
leran and Russell (1990),aegirine-augite pegmatites and al-
lanite pegmatites. They occur in zones l to 4 metres wide
by in excess of 30 metres long; it is unclear, however,
whether they are distinct dikes or, simply, coarse-grained
segregations or pods within fenite zones. The aegirine-
augite pegmatites contain zoned antiperthite (Anz3), sub-
hedral aegirine-augite grains [with inclusions of plagioclase
(An34). sphene, hornblende and biotite], minor perthitic po-
tassium feldspar, occasional elongate quartz crystals and
late, fracture-filling epidote. The allanite pegmatites consist
of perthite, up to 35% allanite, 5 % sphene, plagioclase
(Anzs.27). apatite and minor to trace amounts of aegirine-
augite, quartz, zircon and opaques. Allanite crystals are 0.03
to 2.0 centimetres in size and commonly occur with sphene
and apatite. Late quartz veins, up to 5 centimetres wide, lo-
cally cut the allanite pegmatites.
INTRUSIVE BRECCIAS
An intrusive breccia zone, over 40 metres long, is ex-
posed in one area. It consists of intrusive clasts supported
by a fine-grained, green matrix which contains 25% relic
potassium feldspar, 10%plagioclase, altered blue-green
amphibole and traces of sphene and apatite.
LEGEND
FENITES
Fenitized Wolverine Complex rocks are exposed over &@
A e uncertainplutonic rocks
G r o n o d i k , quartzmonzonite,
tonollle;iocaliy pegmolitic
a broad area. The fenites are generally banded, with melano-
cratic layers consisting of aegirine-augite, sphene, allanite, Hadvnian-
Windermere Supergroup
apatite and minor hornblende, andleucocratic layers domi- Horsethief
Creek
Group, Upper
Clastic
Unit/Koza Group: granule conglomerote,
nated by plagioclase or potassium feldspar and apatite. psammite; minorpeiife carbonate
and
Banding in the fenites reflects original bedding or layering
in the Wolverine rocks which the fenite zones grade into: a Horse!hie! Creek
Group,
Amphlboilte Middle
ond
Semipelile/
Marbleunils;
melanocratic bands were probably amphibolite or biotite amphibolite,
semipelite, marble, minor
schist layers while the leococratic bands were probably pelite
original quartzofeldspathic layers. Fenites are differentiated Horsethief
Creek Group, Aluminous
from hostrocks the presence aegirine-augite and rare-
by of Peiite unit: pslite
predominates:may
earth element bearing minerals, an increase in alkali feld- also contain minoramounts of Lower
Gril
Unit
spar and a decrease quartz.
in
Hadrynian Older
and (Proterozoic)
Malton
gneiss: ortho and parogneiss
QUARTZ MONZONITESAND QUARTZ
SYENITES Geological contact .......... -----------
Fault ..............................
Fine-grained, massive, leucocratic quartz monronite Thrust fouit .................... -7-c
and quartz syenite intrusions are also present in the Mount Corbonatite/nepheiine
Bisson - Munroe Creek area. They are very fresh in appear-
rvenite localities ............................ 0
ance and maybe unrelated to the more alkaline rocks. 'There -
are at least four large intrusions (1 by 3 km in size) and a Fig,ure33. Geology and CarbonatiteJsyenite localitiesin the Illue
number ofsmaller satellite bodies. They contain quartz, pla- Ri rer m a .
42 Geological Survey Branch

7. -~ ~~~~~~~~ ~
Ministry of Energy, Mines and Petmleurn Resouxes
These values represent total rare-earth concentrations; how- of Kamloops (Figures 1 and 33). All are sill-like bodies
ever, the values are mainly in the light rare earths. Fenites which were intruded prior to the deformation and ~netan~or-
contain 0.07 to 0.64% light rare earths over widths 1to 2
of phism associated with the Columbian orogeny. The car-
metres. bonatites, syenites and hosting sedimentary rocks been have
subjected to three phases of deformation (Plate: 15) and
GEOCHRONOLOGY metamorphosed to upper amphibolite grade (kyanite to sil-
No absolute dating has been done on the alkaline rocks. limanite zone). TheMudLake (83D/3, latitude52c07’55”N.
They obviouslypostdate the Late Proterozoic rocks of the longitude 119°10’44”W), Bone Creek (83D/6: latitude
Wolverine Complex; from published data, the timingof em- 52°17’09”N, longitude 119°09’42”W) and Verity (831Y6,
placement relative to metamorphism is unclear and an upper
limit on the agedifficult to establish. Within the sequence, latitude 52”23’51”N, longitude 119”09’13’W) !showings
the syenitic dikes appear to be the latest alkaline rocks em- (Figure 33) occurbelow treeline at elevations bet ween 600
placed as they crosscut both the alkaline pegmatites andthe and 900 metres; consequently exposure limited. ‘ThePara-
is
fenites. dise Lake (83D/6, latitude 52”24’19”N, longitude
Quartz monzonites and quartz syenites probably post- 119°05’47”W) and Howard Creek (83D17, latitude
date the alkaline rocks andmay he completely unrelated to 52”23’OO”N, longitude 118”53’26‘W) carbonatites are
them; angular fenite xenoliths are reported to occur within above treeline, well exposed and were mapped in datail
the quartz-hearing intrusions. From descriptions given, (Figures 34,35a and 35h).
these intrusions sound as if theyare postorogenic; however, The Verity carbonatites can be reached by trails and
until some radiometricdating is completed, their ages will logging roads which cross the North Thompson River and
remain unknown. intersect Highway 5 at Lempriere Station, approxi.nately 40
kilometres north of Blue River. The Bone Creek showings
BLUE RIVER AREA (83D/3,6,7) are accessed from logging roadwhich leaves Highway 5
a
A number of carbonatite and nepheline syenite layers approximately 23 kilometres of Blue River. The Mud
north
occur within the semipelite-amphibolite division of the Lake carbonatite crops out along Red Sands road, which
the
Hadrynian Horsethief Creek Group the Monashee Moun-
in intersects Highway 5, three kilometres north of B lne River.
tains near BlueRiver, approximately 250kilometres north All roads are passable with four-wheel-drive vehicles. The
Plate 15. Fz folds in banded nepheline syenite, Paradise Lake.
Bulletin 88 43

8. CARBONATITES
Three types of carbonatite occur within this suite. One
is a whitish weathering olivine sovite which contains pre-
dominantly calcite (60-8556). olivine (3-20%) and apatite
(2-20%). Accessory minerals which may be present are
phlogopite (Plate 16), with either normal or reverse pleo-
chroism (up to 8%). diopside (10% or less), magnetitz, il-
menite, pyrite, pyrrhotite, pyrochlore, columbite, zircon,
monazite, allanite and baddelyite. The sovite is usually me-
dium grained and massive, but locally may contain pegma-
titic phases with calcite and olivine crystals 2.5 to 3
centimetres long and magnetite clusters over20 centimtres
in diameter. Zircon crystals up to 3 centimetres long have
also been found.
The second type is a buff-weathering dolomitic car-
bonatite (ranhaugite) with accessory amphibole (5-1 S) %,
apatite (2-10%). magnetite and minor phlogopite.Ilmenite,
pyrochlore, columbite and zircon may be present in trace
amounts. The amphibolemay be richterite, soda-tremolite,
tremolite or actinolite. Apatite and amphibole, within the
rauhaugite, define a foliation parallel to both the edg:s of
the carbouatite and the external schistosity. Locally, compo-
sitional banding with alternating apatite-amphibole-rich
and carbonate-rich layers parallels foliation and contacts
(Plate 17). Pegmatitic segregations are not found in the
ranhaugite, but coarse pyrochlore and crystals ( 1-1.5
zircon
cm long) may be present. Separate bands of sovite and
rauhaugite occur at Verity, Paradise Lake and Hoxard
Creek. Rauhaugiteis present at both the Mud Lake and I3one
Creek localities.
LEGEND The third type ofcarbonatite, biotite sovite, is found at
Carbona{ite, ou{crop
Bedding
SYMBOLS
F, fold axes
Minor folds
-
............... 4 y
2
........16
..........
Paradise Lake only. It occurs as segregations or pods ;asso-
ciated with nepheline syenite. Calcite, biotite, apatite and
magnetite are the primary constituents and nephelinemay
also be present.
4 Sohene-amohibalite
Fault -
...................
NEPHELINE SYENITES
Contour
Interval = 30m
Nepheline and sodalite syenite gneisses crop out in the
ParadiseLakearea (Figure 35). In general, the syenitescom-
prise white to grey-weathering, medium-grained, layered
yE:&ian
Psarnmite,
sernipelite,
and foliated gneisses, concordant with hostrocks of the
and
amphibolite Hadrynian Horsethief Creek Group. Layering and foliation
are parallel to the margins of the gneisses, to bedding in
Figure 34. Geologicalmap of the Howard Creek carbouatite surrounding metasedimentary rocks andto regional lolia-
occurrence. tion.
These syenites are typically composed of micrccline
Howard Creek and Paradise Lake localities are reached by (25-35%). plagioclase (An30 - Ana, 25-35%), nepheline
helicopter, from Valemount. (10-30%) and biotite (7-15%). Accessory minerals may in-
Carbonatites in the Blue River area have been exam- clude muscovite, sodalite, cancrinite, zircon and perthite.
Trace minerals present are calcite, magnetite, pyrrbotitl:, py-
ined periodically since the 1950s, for their vermiculite, ura-
rochlore and uranopyrochlore. The syenite gneisses r e lo-
nium, niobium and tantalum potential. Previous cally migmatitic, with massive, medium to coarse-grained,
descriptions are given by McCammon (1951,1953,1955), of
lensoidal leucosomesthat are composed either nephdine,
Rowe (1958). Currie (1976a). Meyers (1977). Ahroon microcline, plagioclase and sodalite or large perthite crys-
tals (Plates 18 and 19).
(1979, 1980), Aaquist (1981, 1982a,1982b, 1982c), White
(1982, 1985) and Pel1 (1987). Lithologies are very similar MAFIC SILICATE ROCKS
throughout this area and will be described by rock type Mafic and ultramafic silicate rocks are present at
rather than locality. Howard Creek (Figure 34). The most common varicty is
44 Geological Survey Branch

9. Ministry of Energy, Mines and Petroleum Resouxes
Geologicalconloct
Moraine or talus
defined, assumed
approx, .......-"
"-
INTRUSIVE ROCKS Orientation bedding
of and
parallel
foliation
(SI and S2)
F2 Fold axis
............................................. -
................................................ c-
....................................... xp
HOST ROCKS
Hadrynian
Minor F2 folds
Fault.......................................................
S I axid race
t
-
Bonded
amphibolite ~
syncline, anticline ................................ * I
0
.i
Psammlte,semipelite. and
thin
omphibollte
layers S 2 axial antiform
trace, .........................
olcsilicate SI axial
trace ......................................... Sa Il
+
Figure 35. (A) Geology of the area south of Paradise Lake; (Next page) Cross-sectionA-A', area south
(B)
of Paradise Lake.
Bulletin 88 45

10. INTRUSIVE ROCKS
A
Figure 358 (continued)
Plate 17. Well layered carbonatite, Howard Creek. Layering is
Plate 16. Phlogopite in carbonatite with reverse pleochroism and produced bycompositional variation within the carbonatite and is
distinctive orange colour, from Verity. Long dimension of parallel to the marginsof the layer, external sedimentary b:dding
photomicrograph is 2.5 millimetres, (colourphoto, page 136). and regional foliation.
46 Geological Survey 3runclr

11. Plate 18. Migmatitic leucosome (tine-grained leucosyenite segregations) present
in layered syenites, Paradise Lake
calcite with or without biotite, allanite and apatite The rock
is generally coarse grained with pyroxenecrystals exceed-
ing 3.5 centimetres in length and sphene crystas up to 2
centimetres long. In the strongly foliated varieties, hom-
blende predominates (50-55%), with aegirine-augite,
sphene and biotite abundant and calcite, plagioc1ar.e. apatite,
pyrite and sometimes nephelinetrace constituents. At one
as
locality, themelteigiteis transitional to, and locallycrosscnt
by, a coarse-grained, massive urtite composed of :25 to 40%
nepheline, 10 to 15% potassiumfeldspar, 8 to 15% plagio-
clase, 8 to 15%aegirine, 15 to 20% hornblende and sphene,
biotite and calcite.
FENITES
Mafic fenites, 1 to 30 centimetres thick, separate car-
bonatites and host metasedimentaryrocks. They v a q from
medium to coarse grained and massive to foliated. They are
generally composed of amphiboles (hornblende-actinolite,
45-80%), clinopyroxene(generally diopside or augite, up to
35%). apatite and opaques.Accessory minerals which may
be present are titanaugite, biotite, plagioclase, sphene, epi-
dote, quartz (remnant) and calcite. In some loca:.itiesa bi-
Plate 19. Migmatitic segregations of coarse perthite crystals in otite-vermiculite layer is developed in place of the
layered nepheline syenite gneiss, Paradise Lake. amphibole fenites. In all cases the metasedimentary rocks
adjacent to the fenites appear unaltered.
sphene-pyroxene-amphibolerock or melteigite, which may
be layered andfoliated or massive. It consists of aegirine- GEOCHEMISTRY
augite (approximately 50%), strongly pleochroic horn- The alkaline rocks in the Blue River area shclw distinct
blende (x - honey-yellow, y - dark bluish green, z - dark major element trends of increasing alkalis from carbonatites
forest-green to opaque: 15.30%) and sphene (10-20%).Ac- to syenites, with fenites most similar in composition to the
cessory minerals include nepheline, plagioclase, pyrite and carbonatites (Figure 36; Table 8). Carbonatites (b~th calcite
Bulletin 88 47

12. British Columbia -
albiie
fenite
field
Figure 36. Major elementternary plots, Blue River area alkaline
;ocks.
Figure 38. Ternary fenite plots, Blue River area rocks
and dolomite-rich varieties) are distinct from marbles the
in
host Horsethief Creek Group;the carbonatites c0nta.n s i g
nificantly less silica, aluminum and alkalis than the average
marble and are enrichediron, phosphorus, strontium and
in
rare earths (Table 8). Enrichment in niobium and tartalum
also occurs in the carbonatites (Table 8), %Os values of
up to 0.46%(Aaquist, 1982b) and tantalum
ppm (Aaquist, 1982c) have been
values tc.2400
reported. Calcite carbona..
tites range fromme sovites to ferrocarbonatites. dolomitic
carbonatites may be classified as magnesiocarborlatites
(Figure 37). Fenites are all typical pyroxene-amphibolt:
fenites, pIotting within pyroxene-amphibolefenite fields;
the
rnognesio- ferro- o n b o t h N a20-KzO-Fe203 a n d C a 0 - N a20i-KzO..
corbonatite corbonatite
MgO+FezO3 plots (Figure 38a and b). Syenites frcm tht:
Paradise Lake are miaskitic, generally compositionally
area
close to the 'average' nepheline syenite (Figure 39a m d b).
Figure 37. CaO-MgO-Fe203ttMnO carbonatite plot, Blue River Alkaline rocks contain anomalous amounts of rare:-earth
area. elements, but not to the extent of manyof the comp1t:xes in
-
48 Geological Survey Branch

13. TABLE 8
CHEMICAL ANALYSES,ALKALINE ROCKS, BLUE RIVER AREA
5 6
3.82 6.60 5.26 2.73 7.642.03 12.30 41.03 42.30
59.20 47.01
12.W 35.86
58.W 44.12
58.20 4530 31.80
50.80 47.10
55.80 41.80
46.60 60.50
Ti02 0.16 0.80 0.62 0.02 00
.2 0.70 0.09 0.85 0.13 0.60 0.44 0.82 0.02 0.29 5.65 4.15
0.25 218 1.84 0.40 0.23 0.40 06
.0
0.64 0.65 0.72 0.15 0.15 on 0.24 0.22 2.22 9.62
6.51 10.51 I250 22.60 20.80
20.10 8.42 5.93 9.72 20.10
18.W 4.88 1.03
13.30 853
4.28 10.70 10.30 4.35 7.356.48 7.61
8.41 0.305.177.449.409.68
2.62 2.69 2.20 15.10 856 12.90
3.67 5.36 1.10 7.19 11.10 3.31
0.21 0.23 0.24 0.31 0.38 0.21 0.41 0.37 0 2 0.20
.0.22 0.27
4 0.18 0.01 0.M 0.03 0.41 023 0.12 0.34 0.06 0.15 0.19 0.20 0.03
2.60 6.88 5.59 14.50 19.W 14.80 16.30
15.W 2.65 11.12 9.23
10.76 2.02 0.W 0.310.17 7.14 459 1.40 11.70 1.44 1.W 1290 7.98 4.74
45.40 39.80 40.90 28.10 28.70 32.90 30.64 29.10 20.W
16.81
15.26
42.90 14.40 0.54 0.698.20 13.58
0.83 16.80 23.10 28.70 2.
3 9 14.90 11.50 5.35
Na20 0.10 0.15 0.15 0.10 0.27 0.11 0.05 4.03 1.11 3.60 3.28 0.40 4.06 7.488.27
9.70 4.462.08 9.52 0.12 1.01 1.13 054 26
6 3.w
K20 4.10 0.38 0 4 4.10
.8 02
.5 o . ~ 0.12 0.12
2:
0
0.59 0.64 153
;:$
1.66 3.78 8.W 5.49 5.08 1.201.71 3.50 4.10 1.69 09
.7 0.81 0.13 2.71
d
40.38 35.46 27.12 37.21 20.73 4.98 2.57 0.90
2.02 1.75 1.18 19.29 0.71
2.12 0.21 -.4 2 8
24~ 098 1.11 04
.4 0.23 4.W 4 9
.
0 4.W am 4.W
$9.78 99.86 97.98
97.10
97.W lW.11 98.R 99.63 91.17
98.18 97.601 lW.48 99.31
98.98
99.46 99.29 lW.39
'2 4 <2 1 24 6s 58 I7 5 9 92
<w 2 < 20 CW 75 88 52 IC4 124 I27 3w
16 16
10 18 28 32 18 22 8 22 25 3 6 1 1 9 7 46
Sr 4223 2995 3372 4092 4459 IS25 3276 3549 5312 534 1334 I641 78 2W3 134 152 71
Ba 248 316 315 157 127 427 113 87 467 196 803 810 31912161 238 36
7s I59 934 712 27 M 1118 50 28 159 734 276 462 63 119 155 M3 37
Nb % 41 42 470 7w 1
W 491 117 E5 181 185 303 6
I64 3 16 1
Y 76 68 67 IS 9 2 5 22 16 68 32 33 48 36 19 26 42 17
La 280 254
171 241 103 134 m 174 2H 74 91 183 42 18 33 162 2
cc 539 548371 530 208 279 415 339 470 169 187 370 32 70 302 164 I5
Nd 234 223 147 119 81 114
rn 4 4 1.4 1 1.8
12 39
k 41 36 40 41 3 4 4 4 34 29 22
T* 19 <2 CZ 12s I78 8 IO CZ c2 c2 <2
?h- ~ ~~ ~ c6 0.11 6 6
' c6 ~6
, c6 5 13 W ~
1
Porndire&;

14. I Nephelinite
CHONDRITE-NORMALIZEDREE PLOT
PARADISE,
VERITY,HOWARD
CREEK
lo5j SHOWINGS
BLUE
RIVER AREA
i
Carbmatife
A Fenile
1 o4
Subalkaline
rocks
00' I
.0
30.00
I I I , , , I , I , I I , , I I I , ,
40.00 50.00
,,,,, I , ,
60.00
,,,, I , , ,
70.C
,,
Si09
0 nepheline syenite
m eDlCore0"S
nepheline
syenile
Agpaitic
family
syenite fornily
Miaskilic
t
overage
nepheline
- .-
-
" syenite
1 1 ~ 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 , 1 1 1 11,
La Ce Pr Nd Srn Tb
Eu Dy Ho Tm Yb LL 1
Rare-earth lements
E --
Alkali
basalt
Subalkaline
rocks Figure 40. Chondrite-normalized REE plot - Paradise, V:rity,
Howard Creek showings Blue Riverarea.
30.00 50.00 40.00 60.00 70.0
Si09
Figure 39. Alkali-silica and agpaitic index plots,Blue River area
syenites.
50 Geological Survey Brmch

15. LEGEND
11
2 Nepheline syenite
/IjHorsethief creek met ore dim en la^ rocks
1 Axial
7 trace o f early antiforms
Figure 41. Geology of the Trident Mountain area, Selkirk Mountains(from Pell, 1986b; Perldns, 1983).
I
Plate 20. Coarse-grainedilmenitesegregationin leucosyenite.
Trident Mountain. Plate 21. Typical banded nepheline
syenites, Trident Mountain.

16. Plate 22. Leucosyenite dikescutting mafic, biotite-amphibole
gneiss, Trident Mountain.
- Carbonalile average
1 family
.
. 1.00-
1
<
b
?
0 nepheline syenite
bosolt
Alkali rn mafic ~ ( ~ I c o r e o u ! ;
nepheline family syenite
0.00
60.00 73.0
Si07
Figure 42. Alkali-silica and agpaitic index
plots, Trident Mountain
syenites.
Plate 23. Xenolith of mafic gneiss inbiotite-rich syenite, Trident
Mountain.
52 Geological Survey Branch

17. Minishy of Energy, Mines and Petmleum .Pesources
"
the Rocky and Cassiarmountains (Appendix Enrichment
1). More recent uranium-lead data have been obtained
in light rare earths is greater than in heavy rare earths, as from zircon separates and indicate a mid-Paleoz.oic (1%-
indicated by the shallow slope on the chondrite-normalized vono-Mississippian) age of emplacement. A sample from
rare-earth element plot (Figure 40). Verity yielded an age of approximately 325 Ma (G.l'.E.
White, personal communication, 1984); a prelimi!~ary date
GEOCHRONOLOGY of approximately 328f30 was obtained from Mud Lake
Early attemptsat dating did not providedefinitive re- samples (R.R. Parrish,personalcommnnication,1!)85).Zir-
sults on the ageof the alkaline intrusions in the Blue River cons separated from Paradise Lake syenites, which were
large, equant andclear, provided slightly discordant analy-
area. Potassium-argon dates of 205f8 Ma on phlogopite
ses which suggesteda uranium-lead age of apprc7ximately
from Howard Creek, and 92.5f3.2 and 80.2S.8 Ma on 340 Ma and lead-lead ages of 351 and 363 Ma (Appendix
richterite from Verity were obtained (White, 1982). Suh-
2).
sequently, potassium-argon dates of 20of7 Ma on phlo-
gopite and 94.4+3.3Ma on hornblende from Howard Creek
were obtained (G.P.E. White, personal communication. TRIDENT MOUNTAIN (82M/16)
1984). The young dates (circa 80-90 Ma) are most likely Nepheline syenites were first recognized in tk e Trident
representative of the timing of metamorphism and not the MountainareabyWheeler(1965)andsubsequentkfmapped
emplacement of the igneous rocks.
byPerkins(l983).TridentMountain(latitude5lo.L~4'N,lon-
gitude 118"09' west) is located in the Big Bend cf the Co-
lumbia River, about 85 kilometres northeast of R'xelstoke
and 20 kilometres southeast of Mica Creek (Figwe 'The 1).
0 nepheline syenite
area is very rugged; the syenites are exposed 011 cliffs at
maficcalcareous elevations of 2200 to 3000 metres, adjacent to largc:icefields
nepheline syenite (Figure 41). Access is by helicopter from Revelsbke.
The syenite gneisses at Trident Mountain are whiteto
grey weathering, medium grained and moderately to well
foliated. They are composed of white to pinkish nucrocline
TABLE 9
CHEMICAL ANALYSES OF TRIDENT MOUNTAIN
SYENITES
Si02 5i.59 56.66
57.64
53.72
41.76
T0
i2 0.02 0.802.04
0.26 41.04
21.69
22.39
22.35
15.45
24.36
A1203
81.59 6.24 0.17
2.71 13.15 Fez03
MnO 00
.1 0.44 0.14 00
.8 *>.01
MgO 0.05 1.59 3.10
0.46 i0.W
cao 6.820.59 0.33 8 . 6 0 9
15 .1
Na20 1.72 8.16
6.27 75
.1 1.39
K207.527.968.22
1.986.94
Ni 3 6 11 4 8
CI 21 < 20 19 13 18
CO 16 18 13 14 18
Sr 1234 1713 625 730 1116
B3
E 2992 1211 1156 584 1520
zr 210 338 1562 57 43
Nb <5 358 229 249 33
Y 6 22 16 4 2
La 8 197 1 6 21
Ce 16 275 10 22 32
Nd
Yb
SC 0.1 99
. 0.4 <I Cl
<2 2 11 12
1020 COO
Figure 43. Major element ternary plots, Trident Mountain syenites.
-
Bulletin 88 53