6
negative Eu anomalies. This pattern may be explained by
the combination of the light REE content of monazite
combined with a preference for heavy REE substitution
in zircon.
These heavy mineral sandstone samples were also nor-
malized to the Average Upper Crust for Sedimentary Rocks
standard (Figure 8 Taylor and 060 06McLennan, 1981).
This plot shows overall enrichment of REE with prominent
negative Eu anomalies and slight heavy REE enrichment,
especially for Farr Ranch samples.
The upper limit of detection for Zr in the trace element
geochemical analysis package ordered from ALS Global is
10,000 ppm. Many of the highly mineralized heavy min-
eral sandstones broke this threshold. Rather than reorder
an analysis for this overage, a simple method was devel-
oped to estimate the Zr concentration of highly mineral-
ized sandstones. Hf is found nearly solely within zircon as
a minor substituting element. Figure 9 shows that Hf and
Zr correlate extremely positively (R2=0.9952) for samples
of known Zr concentration (10,000 ppm Zr). Thus, Hf
can be used to extrapolate Zr values for samples that con-
tain over 1% Zr by using the equation of the line of best fit
shown in Figure 9. The results from this extrapolation are
shown in Table 2, notably showing that one sample con-
tains nearly 5% Zr.
Figure 7. C1 chondrite-normalized spider diagram
(McDonough and Sun, 1995) of heavy mineral sandstones
showing highly elevated REE, distinct light REE enrichment,
slight heavy REE enrichment, and prominent negative Eu
anomalies
Figure 8. Average Upper Crust for Sedimentary Rocks-
normalized spider diagram (Taylor and McLennan, 1981)
of heavy mineral sandstones showing highly elevated REE,,
slight heavy REE enrichment, and prominent negative Eu
anomalies. Legend in Figure 7
Figure 9. XY plot of Hf versus Zr showing an extremely
strong positive correlation
Table 2. Laboratory data and extrapolations of Zr from Hf
and total REE and U+Th from “specific activity.” Values
in bold correspond with laboratory values above detection
limits
TiO2 (%)Zr (ppm) TREE+Y
(ppm)
U+Th
(ppm)
Zr (ppm)
from Hf
TREE (ppm)
from Sp.act.
U+Th (ppm)
from Sp.act.
Flat12 8.74 7280 810 120.5 7399 1623 89 13.8
Flat13 2.34 1060 321 27.3 1041 1430 50 3.8
Flat18 0.58 204 150 7.9 193 nd
Hog10 6.89 3780 1446 99.0 3627 1773 119 21.6
Hog16 6.08 8830 1951 202.9 8571 2932 352 81.6
Hog17 23.60 10000 9908 1000 49044 5360 840 207.3
SAN 6 16.90 10000 9628 1000 17230 11872 2149 544.4
SAN54 0.23 264 86 8.3 295 nd
SAN56 1.10 1340 255 35.5 1431 1476 59 6.2
SAN57 18.55 10000 4981 664.6 32334 4581 684 167.0
SAN58 8.21 9280 2222 289.8 9982 1868 138 26.5
SAN60 16.55 10000 7093 959.9 28167 5700 909 224.9
Laboratory data Extrapolations
Sample
"Specific
activity"
(cps/kg)
negative Eu anomalies. This pattern may be explained by
the combination of the light REE content of monazite
combined with a preference for heavy REE substitution
in zircon.
These heavy mineral sandstone samples were also nor-
malized to the Average Upper Crust for Sedimentary Rocks
standard (Figure 8 Taylor and 060 06McLennan, 1981).
This plot shows overall enrichment of REE with prominent
negative Eu anomalies and slight heavy REE enrichment,
especially for Farr Ranch samples.
The upper limit of detection for Zr in the trace element
geochemical analysis package ordered from ALS Global is
10,000 ppm. Many of the highly mineralized heavy min-
eral sandstones broke this threshold. Rather than reorder
an analysis for this overage, a simple method was devel-
oped to estimate the Zr concentration of highly mineral-
ized sandstones. Hf is found nearly solely within zircon as
a minor substituting element. Figure 9 shows that Hf and
Zr correlate extremely positively (R2=0.9952) for samples
of known Zr concentration (10,000 ppm Zr). Thus, Hf
can be used to extrapolate Zr values for samples that con-
tain over 1% Zr by using the equation of the line of best fit
shown in Figure 9. The results from this extrapolation are
shown in Table 2, notably showing that one sample con-
tains nearly 5% Zr.
Figure 7. C1 chondrite-normalized spider diagram
(McDonough and Sun, 1995) of heavy mineral sandstones
showing highly elevated REE, distinct light REE enrichment,
slight heavy REE enrichment, and prominent negative Eu
anomalies
Figure 8. Average Upper Crust for Sedimentary Rocks-
normalized spider diagram (Taylor and McLennan, 1981)
of heavy mineral sandstones showing highly elevated REE,,
slight heavy REE enrichment, and prominent negative Eu
anomalies. Legend in Figure 7
Figure 9. XY plot of Hf versus Zr showing an extremely
strong positive correlation
Table 2. Laboratory data and extrapolations of Zr from Hf
and total REE and U+Th from “specific activity.” Values
in bold correspond with laboratory values above detection
limits
TiO2 (%)Zr (ppm) TREE+Y
(ppm)
U+Th
(ppm)
Zr (ppm)
from Hf
TREE (ppm)
from Sp.act.
U+Th (ppm)
from Sp.act.
Flat12 8.74 7280 810 120.5 7399 1623 89 13.8
Flat13 2.34 1060 321 27.3 1041 1430 50 3.8
Flat18 0.58 204 150 7.9 193 nd
Hog10 6.89 3780 1446 99.0 3627 1773 119 21.6
Hog16 6.08 8830 1951 202.9 8571 2932 352 81.6
Hog17 23.60 10000 9908 1000 49044 5360 840 207.3
SAN 6 16.90 10000 9628 1000 17230 11872 2149 544.4
SAN54 0.23 264 86 8.3 295 nd
SAN56 1.10 1340 255 35.5 1431 1476 59 6.2
SAN57 18.55 10000 4981 664.6 32334 4581 684 167.0
SAN58 8.21 9280 2222 289.8 9982 1868 138 26.5
SAN60 16.55 10000 7093 959.9 28167 5700 909 224.9
Laboratory data Extrapolations
Sample
"Specific
activity"
(cps/kg)