
Biogeochemical
survey of the Drybones Bay area, Northwest Territories
(NTS 85I/4) using outer bark of black spruce
GEOLOGICAL
SURVEY OF CANADA
Open
File D3919
C.E.
Dunn, D. Smith and D.E. Kerr
A
contribution to the Yellowknife EXTECH program and the
Targeted Geoscience Initiative
2001
TABLE
OF CONTENTS
Introduction
Regional
Setting
Biogeochemical
Surveys
Sample
Collection, Preparation and Analysis
Discussion
Results
Conclusions
Acknowledgements
References
Appendix
A
Appendix 1 Spruce
bark ash B all analytical data
Appendix 2 Controls
on accuracy
Appendix 3 Controls
on precision
Appendix 4 Spruce
bark ash B analytical data with field coordinates (Zone 12)
Appendix 5 Spruce
bark ash B Statistics (Mud Lake area)
Appendix 6 Average
concentrations by area
Appendix
B
Element plots (dots proportional
in size to percentile values)
Elements arranged in alphabetical order by chemical name
LIST
OF FIGURES
Figure
1. Location Map
Figure
2. Locations of survey areas
Figure
3. Detail of Mud Lake area with bark sample sites
Figure
4. Contoured bark data for Au, As, Sb and Te
Figure
5. Locations of till samples and count of mantle garnets (after Kerr
et al., 2001)
Figure
6. Proportional dot plots of W, Sr, Be and mantle garnet counts
Figure
7. Proportional dot plots of Rb, Cs, Zn and Ni
INTRODUCTION
Black spruce is the most common tree species throughout
large areas of the boreal forests of Canada, and many elements concentrate
in its outer bark. As part of the Yellowknife EXTECH program, black
spruce bark was selected as the sample medium for biogeochemical surveys
in three areas near Drybones Bay, on the east side of Great Slave Lake,
N.W.T. (Fig. 1). This
study complements other on till studies in the same area (Kerr et al.,
2000, 2001a) and provides new insight to the chemistry of the underlying
rocks and their potential for hosting mineralization. Much of the report
focuses on an area centred 4 km southeast of Drybones Bay, approximately
45 km southeast of Yellowknife, in a region informally called Mud Lake
(Fig. 2). Two smaller
areas with more limited sampling are located on the north and south
sides of Drybones Bay, near the diamondiferous Drybones Bay kimberlite.
The second
author collected samples on an opportunistic basis during prospecting
traverses. Sampling was to a degree dictated by the occurrence of lakes
and bogs, but where possible along traverses a consistent spacing of
100 m between sample sites was maintained. However, the resultant sampling
pattern is not an even sampling grid (Fig.
3).
Please
note that sample site no. 84 to 89 which plot north of Sipper Lake (figures
and Appendix B) should, in reality, plot 1 km due south, on the south
side of Sipper Lake. The UTM coordinates in Appendix
4 are correct.
REGIONAL
SETTING
Bedrock
Geology
The survey area lies within the southern Slave Structural
Province of the Canadian Shield. Although there are many lakes, bogs
and areas with glacial drift cover, outcrops occur at many locations.
The dominant rocks are Archean granite, granodiorite and tonalite overlain
locally by metasedimentary schists of the Yellowknife Supergroup (Henderson,
1985). A diamond-bearing kimberlite pipe discovered in 1994 in a small
bay on the southern side of Drybones Bay (Fig.
2) remains the only kimberlite discovered to date along the western
margin of the Slave Craton. It intrudes Archean granitoids and subcrops
beneath 67-77 m of lake bottom sediments and a water depth of 38 m.
Preliminary dating of the 900 m by 400 m Drybones kimberlite gives an
age of 441-485 Ma (Kretschmar, 1997). It is a complex intrusion with
7 lithotypes forming crater facies, diatreme facies and thin basal facies.
It contains abundant olivine, ilmenite, pyrope and chromite in a matrix
of serpentine clays, calcite and chlorite (Kretchsmar, 1997)
Glacial
History, Physiology and Surficial Geology
The Yellowknife region was ice-covered during the Late
Wisconsin glaciation until about 10 000 BP (Dyke and Prest, 1987). Ice
flow indicators show that ice movement was toward the southwest, with
minor divergences related to local topography as the ice sheet thinned
and receded (Kerr and Wilson, 2000; Kerr et al., 2001b)Glacial Lake
McConnell occupied a large area along the western margin of the retreating
ice up to an elevation of 280 m (Craig, 1965), and as water levels fell
extensive reworking of sediments took place. Great Slave Lake reached
its present level of 157 m a.s.l. by about 8 500 BP (Vanderburgh and
Smith, 1988).
Boulder-strewn
outcrop interspersed with pockets of sandy till dominate the low relief
of the Drybones area. Organic sediments in the topographic lows between
the outcrops support a typical boreal vegetation of stunted black spruce
(Picea mariana), alder (Alnus spp.), Labrador tea (Ledum
spp.) and other small shrubs and sedges. More detail of the glacial
history and surficial geology is provided in Kerr et al. (2001b)
BIOGEOCHEMICAL
SURVEYS
The roots of a single large tree extract elements
from many cubic metres of soil, overburden, groundwater and sometimes
bedrock. These elements are then transferred to aerial parts of the
tree where they may concentrate. Data derived from the analysis of an
appropriate vegetation sample medium permits geochemical mapping, with
enhanced background to anomaly contrast of certain elements, which may
outline broad geochemical patterns, and assist both in mapping bedrock
and in the search for concealed zones of mineralization.
Whereas
till geochemistry provides valuable information on the elemental composition
of surficial sediments and their provenance, consideration of analytical
data from vegetation penetrating the till provides additional insight
to the chemical nature of the substrate. Locally, comparison of till
and biogeochemical data can assist in determining vectors and distance
from a mineralized source (Dunn, 1998). There are commonly some similarities
in element distribution patterns derived from the two sample media,
but also some significant differences that require some explanation.
Firstly,
analysis of a till sample involves sieving and selection of one size
fraction from a bulk sample commonly weighing 5 - 10 kg, dug from a
single small pit. The tree roots, however, may extend downwards and
outwards through several cubic metres of till (all soil horizons), and
on occasion reaching and penetrating joints and fractures in bedrock.
The tree, therefore, extracts elements from a large volume of material
of diverse composition, including groundwater. Some elements that are
dissolved in groundwater can be readily extracted by the tree roots,
but may not precipitate in till and on soil particles.
A second
factor of importance is the barrier mechanism established at the root/sediment
interface by some plants for some elements (Kovalevskii, 1979). Because
each species of plant has a different requirement for, and tolerance
to, a range of chemical elements, some partitioning of elements takes
place and there is selective absorption and transference into the plants.
For biogeochemical exploration, conifers are good sample media because
they are primitive plants that have a wide tolerance to many trace elements.
The outer bark may, by analogy, be equated with biotite in rocks, in
that it is something of a repository for many elements that do not fit
elsewhere or are not required for the metabolic function of the tree.
A third
factor is that slight enrichments of metals in till samples are unlikely
to be reflected in the vegetation as weak biogeochemical anomalies.
This is especially true in the ppb (Au) and ppm ranges of element concentrations
common in till samples. Some elements may not be present in a chemical
form that is available for uptake (e.g. Cr structurally bound in chromite).
Some may be excluded from uptake at the roots or only partially absorbed,
and some may be taken up but dispersed among tree tissues to the extent
that inter-site variations are so small that they cannot be detected.
The net
result of these factors is that the geochemical information supplied
by the vegetation is different from that of the till. Just as two methods
of a geophysical survey will provide totally different information,
so will two methods of a geochemical survey. A high correlation between
distribution patterns of two geochemical sample media is the exception
rather than the rule. In geological environments where there is sufficient
concentration of metals to form a mineral deposit, such a critical mass
of elements may be sufficient to generate biogeochemical anomalies above
(by upward diffusion) or close to (by movement, for example, in electrochemical
cells) the mineral source. Tills, however, usually have geochemical
anomalies displaced down-ice from the mineralized source. Such factors
need to be taken into consideration when interpreting geochemical results.
SAMPLE
COLLECTION, PREPARATION AND ANALYSIS
Samples of the loose outer bark scales from black spruce
were collected from 165 sites in the Mud Lake area, 12 sites on the
north side of Drybones Bay, and 5 sites from 0.5- 1 km down-ice (southwest)
from the Drybones kimberlite, described above, which lies beneath a
bay on the south side of Drybones Bay (Fig.
2).
A paint
scraper was used to remove 50-100 g of outer bark from around the circumference
of black spruce. The scrapings were transferred into bags, and sent
to Activation Laboratories Ltd. (Ancaster, ON) where they were reduced
to ash by controlled ignition at 470C for 24 hours. They were then digested
in strong acid (aqua regia) and the solution analyzed for approximately
60 elements by inductively coupled plasma mass spectrometry (ICP-MS).
This technique provided data on the total or near total concentrations
of most elements. Data for most of the elements reported are presented
in Appendix 1,
which includes the detection levels for each element (second row) and
all quality control samples. Appendix
2 is a listing of data obtained on the control sample V7a - a vegetation
ash of known composition used to assess analytical accuracy. Analytical
precision was monitored by repeat analysis of selected samples (Appendix
3).
All
data reported are concentrations in ash remaining after controlled ignition
at 470C. For bark of black spruce, the ashing process concentrates the
elements with little or no losses except for a few of high volatility
(e.g. Br and Hg). Appendix
1 includes only data for those elements for which accuracy and precision
were within acceptable limits. These limits varied for each element
according to concentration levels, but were generally within +/- 10%.
Rather than defining a tight statistical control on the acceptability
of data, each element was reviewed and evaluated. As a result of this
evaluation B, Si, Ge, Se, Zr, Sn and Ba were excluded from all data
listings. Most K values were above the detection level (approximately
10%) and so the laboratory coded them as >999999. Although the Ba
data were mostly well within acceptable limits, data for the final batch
were substantially lower, probably because of precipitation as BaSO4
during the digestion procedure. Data for Cu are included although it
should be noted that for the control V7a, there appears to be some instrumental
drift toward the end of the last batch. Copper concentrations for other
samples in this batch appear to be of the right order, and so it could
be just a problem with the control. The digestion of ash appears to
have extracted only a small portion of the contained Cr; however, the
precision (Appendix
3) is good. Concentrations below detection are recorded as half
the detection level. Appendix
4 lists the ICP-MS geochemical data and location by UTM (Zone 12)
for each sample. Appendix
5 represents the statistical data for each element as plotted in
Appendix B, whereas Appendix
6 presents the average concentration of elements in the three study
areas.
DISCUSSION
The interpretation of biogeochemical data should be undertaken
with due consideration to chemical requirements and tolerances of plants.
Plants require certain elements for their survival, and they have the
ability to concentrate metals by scavenging them from the substrate.
Zinc, for example, is needed for plant metabolism. Therefore, subtle
differences in Zn concentrations between sample sites are more likely
to reflect the health of the plant than significant differences in the
chemistry of the substrate. However, major differences in Zn concentrations
may reflect the presence of Zn mineralization. By contrast, plants also
have the ability to exclude those elements that would have a detrimental
effect on their growth or health. The 'barrier' mechanism (Kovalevskii,
1979) mentioned above might result in only weak enrichment of an element
in a tree from an environment where that element may be enriched in
the substrate. As a consequence, for some elements there may be no simple
relationship between the chemistry of a tree tissue and the chemistry
of the soil and underlying parent material. A brief discussion to assist
in data interpretation is given in Dunn et al. (1996) on the role of
each element in plant function. Biogeochemistry is a complex science
involving the interaction of many organic and inorganic processes. However,
careful and systematic collection and preparation of plant samples can
provide cost-effective new insight into the chemistry of the substrate
and its groundwater.
In light
of the occurrence of one diamondiferous kimberlite at Drybones Bay and
anomalous concentrations of kimberlite indicator minerals 3 km to the
southeast (Kerr et al. 2001a), of particular interest in this study
is the possible occurrence of additional kimberlitic bodies. There is
unusual abundance of many trace elements in kimberlite (Dawson, 1980).
In general, kimberlites are characterized by high content of elements
compatible with ultramafic rocks (Mg, Cr, Ni, Co), and concentrations
of many other incompatible elements to levels that are higher than usual
for ultramafic rocks (especially K, P, Zr, Nb, Sr, Ba, Rb, Cs and the
light REE).
A number
of case studies address the issue of biogeochemical response to kimberlite:
- Enrichment
of Sr, Rb, Ni, Cr, Nb, Mg and P (and depletion in Mn and Ba) was noted
in a study of 48 elements in several species growing over the Sturgeon
Lake kimberlite in Saskatchewan (Dunn, 1993).
- In northern
Ontario several species growing over three kimberlite pipes exhibited
enrichments of Sr, Rb, Be, Mo, Au, Cr, Ni, Cu, Co, Cs, Na, Al, Cd, Zn
and REE. Black spruce bark was only notably enriched in Sr, Ba and Zn
(McClenaghan and Dunn, 1995).
- Over
the Peddie kimberlite in northern Ontario, several species were variously
enriched in Sr, Rb, Ni, Co, Cr, As, Cd, Nb, Ta, Zr, K, Mg, Th and Tl
(McClenaghan et al., in prep.).
- In Alberta,
the Mountain Lake ultramafic intrusion is similar in composition to
kimberlite and yielded a biogeochemical response in Rb, Ni, Cr, Co,
Mg, Au, Fe, Na, V, W and the light REE (Eccles, 1998).
Clearly, there is a wide range of trace elements that may be enriched
in tissues of different plant species growing over kimberlites. Several
elements appear consistently in the above studies; Rb, Ni, Cr and many
others are noted in 3 of the 4 studies.
RESULTS
In general, element concentrations are similar to those
found in black spruce bark from elsewhere in the boreal forests of Canada.
There are, however, a few exceptions, the most notable of which are
elevated levels of Au, As and locally Sb. Typically, this suite of elements
is indicative of gold mineralization. Other elements are quite highly
enriched at a few sites: Li, Mo, Cr, Cd, Cs and W. Of greater significance
than the absolute concentrations are the spatial relationships of relative
enrichment of several elements and subtle enrichment of several elements
(e.g. Bi, Te).
There are
no obvious indications of either base metal or platinum group metal
mineralization. Base metal levels are close to usual background concentrations
in spruce bark ash; data for Pt and Pd were not obtained, but elements
commonly enriched with PGE mineralization (e.g. Ni) are not enriched.
Of note are: a) indications of Au; and b) possible kimberlites, especially
when viewed in conjunction with the detailed glacial dispersal and indicator
mineral studies of Kerr et al. (2000, 2001).
Mud
Lake Area
Gold
Concentrations of Au and As are significantly higher
than those typically found in the ash of black spruce outer bark. For
example, in the Star Lake area of Saskatchewan, the mean of 560 samples
was 8 ppb Au, 5.7 ppm As and 2.2 ppm Sb (unpublished data of the first
author; summary information in Dunn et al., 1990). By contrast, trees
in the Mud Lake area have average concentrations of 27 ppb Au, 64 ppm
As and 4.1 ppm Sb. The closest gold mine operations are near Yellowknife,
some 45 km to the northwest. Nickerson (1999) reported Au values in
black spruce bark ash ranging from a few hundred ppb to >1000 ppb
Au near the Con and Giant mines, Yellowknife. Arsenic concentrations
were commonly from 100 to >1000 ppm As. Unpublished data supplied
by the third author on metals in humus demonstrate that for 25 to 50
km upwind (northwest) from Yellowknife the average concentrations are
25 ppm As and <8 ppb Au, whereas for 25-50 km downwind (southeast)
As decreases from 120 ppm at 25 km to 50 ppm at 50 km, Au from 12 to
6 ppb, and Sb from 4 to 1 ppm. It is, therefore, possible that mining
operations around Yellowknife have contributed to the Au, As, Sb signature
of the spruce bark from the Drybones Bay area by atmospheric transport
of airborne particulates. However, values in the Mud Lake area are quite
variable and samples to the west of the Drybones kimberlite, several
kilometres closer to Yellowknife, yielded typical average background
levels for spruce bark of only 5 ppb Au. If the sole source of the elevated
levels of Au, As and Sb was from airborne contamination, then it might
be expected that there would be moderate consistency to the concentrations
of these metals in the survey area. This is not the case, therefore
it appears that at least some of the element signatures in the Mud Lake
area are related to local sources of metal enrichment.
Figure
4 shows the contoured data for Au, As, Sb and Te. Relative enrichments
are observed:
- at
the west end of Fastner Lake (Au, As, Sb)
- to
the north and south of Swamp Lake (Au, Te)
- near
a small lake in the southeast corner of the survey area (Au, As, Sb)
- south
of Chanky Lake As, Sb and Te show relative enrichment, with no associated
Au.
It should
be noted, however, that the maximum Au value is 86 ppb. This could represent
modest, yet uneconomical Au mineralization near surface, or more significant
grades at greater depth. The implication from the arsenic is that there
is a high regional background in As with which Au is locally associated.
Kimberlite
Figure 5 shows
locations of till samples collected by Kerr et al. (2001a) and the total
counts of mantle garnets at each sample site. This is clear evidence
of a local kimberlite source, presumably up-ice to the east northeast.
Figure 6 shows
concentrations of W, Sr, and Be in the Black Spruce bark, and a repeat
of Fig.5 for comparison.
Each of these elements indicates local up-ice enrichments. Tungsten
is of particular note with relative enrichment in the spruce bark immediately
up-ice from the till samples with high mantle garnet counts, and trailing
northeast toward Sipper Lake. Beryllium shows a similar pattern. Close
to the west shore of Grass Lake (the small lake immediately south of
Swamp Lake) there is enrichment of both Sr, in addition to W and Be.
The rare earth elements, with Eu as an example (see plot in Appendix
B) show a similar pattern to the Sr. Similarly, these elements show
slightly elevated levels at the south end of a small lake in the southeast
corner of the study area. Each of these elements has been recorded as
being enriched over kimberlites elsewhere in Canada (see 'Discussion',
above).
Figure
7 shows plots of Rb, Cs, Zn and Ni. Relative enrichment of these
elements occurs near the southeast corner of Swamp Lake and at the same
small lake in the southeast corner of the study area. Other elements
with elevated levels in the same general areas include Cu, Ag, Co, and
Li (Appendix B). Also enriched
near Swamp Lake are Mg, U and Mo; several other elements yield elevated
levels in the southeast corner (Appendix
B).
Previous
biogeochemical studies of kimberlites have indicated that most element
enrichments are closely confined to the extent of the kimberlite. Given
this observation, and the high numbers of mantle garnets, areas that
warrant focussed attention in conjunction with geophysical results are:
- the
west side of Grass Lake (200 m south of Swamp Lake), and beneath that
lake
- the
southeast corner of Swamp Lake and beneath the lake
- between
Swamp Lake and Sipper Lake
- the
southeast corner of the survey area.
Drybones
Kimberlite
A half to 1 km west-south-west of the Drybones kimberlite
(Fig. 2), five samples
of black spruce bark were collected to determine if they yielded a biogeochemical
signature that might be diagnostic of the nearby kimberlite. If so,
then such information could be used elsewhere to assist in defining
a vector toward other possible kimberlite bodies. As noted above, biogeochemical
responses seem confined to the extent of the underlying kimberlite.
This is because the signature of a few grains of kimberlite smeared
down-ice by glacial dispersion is insufficient in concentration for
a biogeochemical signature to be recognized. This appears to be the
case with the Drybones kimberlite. The 5 bark samples had similar mean
concentrations of elements to those in the other two survey areas (Appendix
6) except for enrichment in As, Sb, Mn and Ca. Gold, Pb, Bi, Sr,
Tl and U were depleted with respect to the other areas. Only site #DN-118
(Appendix 1) yielded
elevated levels of Ni (54 ppm). Although one of the highest values for
the entire dataset, a concentration of this magnitude is not unusual,
and actually lower than might be expected for mafic rocks.
North
of Drybones Bay
On the north side of Drybones Bay, at a distance of 1-2
km from the east shore of Great Slave Lake, 12 bark samples were collected
at spacing of 300 to 500 m (sites #DN146 to 157, Appendix
1). No extreme values were found in any sample, and mean values
were very similar to those from the much larger population of the Mud
Lake survey area. The generally elevated levels of Au and As again appear
to attest to a regionally high background concentration for these elements
(see discussion under 'Gold'). The range in Au values was from 7 to
44 ppb, with the higher values occurring in the more northerly sites
of the traverses (DN-151 to 157).
CONCLUSIONS
The biogeochemical survey of the three study areas has
indicated several sites that are worthy of closer investigation for
potential gold mineralization and the presence of kimberlites. As with
any surficial geochemical dataset, data should not be viewed in isolation,
but in conjunction with environmental, geological and geophysical information,
and detailed knowledge of the geologist who has studied the local physical
and geological environment.
ACKNOWLEDGMENTS
The
second author extends thanks for the encouragement provided by Dave
Nickerson, and for his time and patience in explaining the sampling
methods and refining procedures. I. McMartin critically reviewed the
manuscript. Digital formatting for the CD-ROM was prepared by Alalonde
Corporation.
REFERENCES
Craig,
B.G. |
1965: |
Glacial
Lake McConnell, and the surficial geology of parts of Slave River
and Redstone River map-areas, District of Mackenzie; Geological
Survey of Canada, Bulletin 122, 33 p.
|
Dawson,
J.B. |
1980: |
Kimberlites
and their xenoliths. Springer-Verlag, Berlin, 252 p.
|
Dunn,
C.E. |
1993: |
Diamondiferous
kimberlite in Saskatchewan, Canada: a biogeochemical study. J. Geochem.
Explor., 47, p.131-141
|
Dunn,
C.E. |
1998: |
Regional
and Detailed Biogeochemical Surveys in the Nechako NATMAP Area and
in the Babine Porphyry Belt. In: New Geological Constraints on Mesozoic
to Tertiary Metallogenesis and on Mineral Exploration in central
British Columbia: Nechako NATMAP project (Eds. L.C. Struik and D.G.
MacIntyre). GAC Cordilleran Division Short Course Notes.
|
Dunn,
C.E., Balma, R., and Sibbick, S.J. |
1996: |
Biogeochemical
survey using lodgepole pine bark: Mount Milligan, central British
Columbia (Parts of NTS 93N/1 and 93O/4) Geological Survey Canada,
Open File 3290, and BC Geological Survey Open File #1996-17, 69
p. + maps.
|
Dunn,
C.E., George, H., and Spirito, W. |
1990: |
Patterns
of metal enrichment in vegetation in relation to geology and gold
mineralization: Star Lake area, Saskatchewan. In: Modern Exploration
Techniques (Eds. L.S. Beck and C.T. Harper), Sask. Geological Society
Special Publication No. 10, p. 12-26.
|
Dyke,
A.S. and Prest, V.K. |
1987:
|
Paleogeography
of northern North America 11 000 - 8 400 years ago; Geological Survey
of Canada, Map 1703A, 3 sheets, scale 1:12 500 000.
|
Eccles,
D.R. |
1998: |
Biogeochemical
orientation survey of the Mountain Lake diatreme, Alberta: Alberta
Geological Survey, Open File Report 1998-06
|
Henderson,
J.B. |
1985: |
Geology,
Yellowknife - Hearne Lake, District of Mackenzie, Northwest Territories;
Geological Survey of Canada, Map 1601A, scale 1: 250 000.
|
Kerr,
D.E., Smith, D., and Wilson, P. |
2000:
|
Anomalous
kimberlite indicator mineral and gold grain abundances, Drybones
Bay and Yellowknife area, Northwest Territories; Geological Survey
of Canada, Open File D3861.
|
Kerr,
D.E., and Wilson, P. |
2000: |
Preliminary
surficial geology studies and mineral exploration considerations
in the Yellowknife area, Northwest Territories; Geological Survey
of Canada, Current Research 2000-C3, 8 p.
|
Kerr,
D.E., Kjarsgaard, I.M., and Smith, D. |
2001a: |
Chemical
characteristics of kimberlite indicator minerals from the Drybones
Bay area (NTS 85I/4), Northwest Territories; Geological Survey of
Canada, Open File D3942.
|
Kerr,
D.E., Knight, R., Smith, D., and Nickerson, D. |
2001b: |
Drift
prospecting investigations in the Yellowknife Greenstone Belt, Northwest
Territories; Geological Survey of Canada, Current Research 2001-C1,
7 p.
|
Kovalevskii,
A.L.
|
1979: |
Biogeochemical
Exploration for Mineral Deposits. Oxonian Press Pvt. Ltd., New Delhi,
136 p.
|
Kretschmar,
U. |
1997: |
Drybones
Bay kimberlite: summary and exploration update; Exploration Overview
1996, NWT Geology Division, Indian and Northern Affairs Canada,
Yellowknife, p. 3-27 to 3-28.
|
McClenaghan,
M.B. and Dunn, C.E.
|
1995:
|
Biogeochemical
survey over kimberlites in the Kirkland Lake area, northeastern
Ontario; Geological Survey of Canada, Open File 3005, 69 p.
|
McClenaghan,
M.B., Kjarsgaard, B., Dunn, C.E., and Hall, G.E.M.
|
In
prep: |
Biogeochemical
study of the Peddie kimberlite, Lake Timiskaming area, Ontario,
Geological Survey of Canada, Open File 3261
|
Nickerson,
D. |
1999:
|
EXTECH
III biogeochemical survey - Yellowknife area, 1999, NTS85 J/9, Northwest
Territories. Geology Division, Indian and Northern Arrairs Canada,
Open Report 1999-02.
|
Vanderburgh,
S. and Smith, D.G. |
1988: |
Slave
River delta: geomorphology, sedimentology and Holocene reconstruction;
Canadian Journal of Earth Sciences, vol. 25, p. 1990-2004.
|
|