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Figure 5 - Regional scale linears identified based on topography.
Linears from Magnetics
The regional magnetic data are useful for outlining lineaments (Figures 6 and 7). In this case,
the magnetics are most effective in mapping fault offsets of regional stratigraphic units or
intrusives that have varying magnetic intensity. These linears are typically northeast trending
cross structures. The northwest trends parallel major lithologies and the Cordilleran tectonic
trend, and may or may not be fault contacts.
The dashed lines in Figure 6 show linears from total field magnetics and have been drawn
where major offsets are evident. There is a significant set of east-northeast (N65
o
E) linears with
a periodicity of 50-75 km, evident particularly in the central portion of the map. These could
represent major cordilleran cross structures and they are, in fact, sub-parallel to the Skeena
Arch (see Figure 10), a major uplift and centre of intrusive activity to the north of the Property.
Another significant trend noted in this figure is northerly, in the central part of the map area,
cutting through the area of the Property. To the east, very prominent west-northwesterly linears
parallel the Pinchi Fault and Rocky Mountain Trench. The major east-west structure that strikes
through Endako is evident on the western half of the map area.
The first vertical derivative (1VD) map (Figure 7) provides greater detail of magnetic patterns.
The cross linears are evident, but that they are at a steeper angle than was noted for the total
field magnetics, closer to 45
o
. The difference could be attributed to the total field magnetics
reflecting deeper features while the 1VD magnetics may reflect shallower features. Several
north trending linears are evident, but they don’t correlate with the north trending linears in the
total field magnetics.
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Figure 6 - Regional scale linears based on regional total field magnetics.
Figure 7 - Regional scale linears based on regional first vertical derivative magnetics.
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Linears from Gravity
The regional gravity data is quite course and, as a result, the Bouger gravity map tends to
reflect only deep structures or features. In the case of Figure 8, the dashed red lines indicate a
number of east-northeast linears that are roughly parallel to those defined by the total field
magnetics. In the central and eastern portions of the map, north trending linears are strongly
defined. The rectangular pattern divides the area into 50 to 100 km wide cells that could be fault
bounded blocks uplifted or down-dropped relative to each other.
Figure 8 - Regional scale linears based on Bouger gravity.
Summary of Regional (1:1,500,000) Scale Linears
Figure 9 depicts a compilation of all the linears determined from the above data superimposed
on topography. Figure 10 shows the same compilation on the Bouger gravity image and Figure
11 on the Terrane map. Also shown are the Skeena Arch, the Topley Magmatic Arc, which
includes the Endako Batholith, (Bright, 1964; Chapman, pers. com.) and significant mines and
occurrences. Those areas where three or more linears from different data sets aligned were
combined into a single thicker line.
Northeasterly linears, roughly parallel with the Skeena Arch, dominate the map, along with a
significant north-south linear corresponds with the Fraser River valley, through Prince George
and Quesnel and the strong east-west linear, previously noted, cuts through Prince George and
Vanderhoof, just to the south of Endako and just north of the Property. Of particular interest is a
swarm of north-south linears through the central portion of the study area.
The Xama property is located near the intersection of the important east-west linear, a strong
northeast trending linear and a weaker north-northeast linear. When examining Figure 10, with
the gravity background, it appears that many of the deposits may occur within specific, fault
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Figure 9 - Regional scale linear compilation (lines with 3 or more superimposed linears
are thicker than 2 or less).
Figure 10 – Regional scale linear compilation on Bouger gravity map.
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bounded blocks rather than along specific linears. At this scale of examination, it may be equally
important for a deposit to be proximal to a linear as to be directly on it.
Of particular interest is the cluster of north-south linears in the centre of the map area in a 100
km wide swath that contains the Property as well as Endako, Capoose, Chu and Blackwater-
Davidson. This trend is also defined by a north trending gravity low (Figure 10). If these linears
reflect extensional fractures, they could be important for the localization of intrusive centres and
for ore forming fluid migration, especially where they intersect other lineaments.
Figure 11 - Regional scale linear compilation over GSC terrane map of BC.
P
ROPERTY
1:100,000
S
CALE
A
NALYSIS
The property scale analysis was conducted using topographic and magnetic patterns from BC
MapPlace at a scale of 1:100,000. Magnetic data include both total field and 1VD magnetics. As
was done for the regional setting, linear features were identified on each map and compiled.
From the compilation map, target identified for further exploration were determined based on
intersections along main lineaments, as well as other supporting data. As mentioned above,
most of the local scale structures recognized in the Endako area are related to Tertiary
extension (Lowe et al, 2001) and, unless they represent remobilization of older structures, they
would be post-ore in terms of Endako style porphyry molybdenum mineralization. However, they
could be important in the localization of younger Blackwater style gold mineralization.
Linears based on Topography
Linears defined by topography are indicated in Figure 12. Some of the most obvious features
are northeast and north-northeast trending and relatively short length, but north, west-northwest
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