Kyanite, Sillimanite, and Andalusite Deposits of the Southeastern ...

GEOLOGY OF THE DEPOSITS 9
TABLE 3. Chemical and spectrochemical analyses of kyanite
quartzite and sillimanite quartzite from Farmville district,
Virginia, and Kings Mountain district, North Carolina-
South Carolina
VB-W
Ky anite quartzite
SY-87
NG-437
Sillimanite quartzite
NG-439
NG-440
Chemical analyses
[VB-W: L. D. Trumbull, analyst; SY-87, NG-437, NG-439, NG-440: L. N.
Tarrant, analyst]
Location of samples:
VB-W, Lab. No. 53-835SCD. Composite sample of kyanite quartzite
from 6 pieces of diamond-drill core from 5 drill holes, Willis Mountain,
Buckingham County, Va.
SY-87, Lab. No. 52-1611CDSW. Composite sample of kyanite quartzite
taken from 6 places in northern opencut of Commercialores, Inc.,
Henry Knob, York County, S.C.
NG-437, Lab. No. 52-1605CDSW. Composite sample of 6 pieces of
kyanite-chloritoid quartzite taken across strike of 10-foot bed, 1.2 miles
S. 10° W. of Crowders Mountain Village, Gaston County, N.C.
NG-439, Lab. No. 52-1607CDSW. Composite sample of 6 pieces of sillimanite
quartzite from crest of Reese Mountain, Lincoln County, N.C.
NG-440, Lab. No. 52-1608CDSW. Composite sample of 6 pieces of sillimanite
quartzite from Will Knox property, Gaston County, N.C.
SiO 2 ...............
Fe 2O3.. ............
FeO
MgO...............
CaO...............
Na2O ..............
K2O ...............
H2O ..............
H2O + .............
TiC-2...............
CO2 . ..............
P 2Os.........
F..... .............
S.. ................
MnO. .............
68.71
27.61
.57
.04
.14
.41
.00
.14
.04
.32
1.02
.02
.32
.00
73.56
17.01
.00
5.25
.01
.00
.00
.00
.01
.12
.48
.01
4.62
.00
63.35
28.97
2.25
2.50
.31
.07
.13
.04
.05
1.30
.86
.01
09
.05
75.33
23.36
.04
.18
.01
.01
.02
.10
.02
.19
.60
.02
.06
.00 (Tr.)
69.59
27.24
.17
.13
.01
.17
.00
.00
.01
.58
1.46
.02
.33
.03
.00 (Tr.)
Total... ..........
Less O for F. .....
Less O for S ......
99.55
.09
101.18
1.16
99.74
.01
Total. ...........
99.46
100.02
99.98
99.94
99.73
Spectrochemical analyses
[P. R. Barnett, analyst. Zeros in unit column signify that the elements
were not detected; sensitivity limits for these elements are: B, 0.003;
Be, 0.0001; Co, 0.0005 ; Ga, 0.0005 ; La, 0.005 ; Mo, 0.0001; Ni, 0.0003 ; Pb,
0.0006 ; Sn, 0.001; Sr, 0.0008 ; Y, 0.001 ; Yb, 0.0001; Zn, 0.01. Elements not
detected in any of these samples, together with their sensitivity limits, are:
Ag, 0.0005; As, 0.05; Au, 0.003; Bi, 0.001 ; Cd, 0.005; Ge, 0.0005; In,
0.001; Nb, 0.001; Pt, 0.003 ; Sb, 0.01 ; Ta, 0.05 ; Th, 0.05 ; Tl, 0.01; U, 0.05 ;
W, 0.01]
B..... ...... .......
Ba..... .......
Be..... ............
Co..... ....
Cr. ................
Cu ................
Ga. . ............
La.................
Mo.... ........
Ni... ......
Pb.........
So.......... .....
Sn.........
Sr .................
V........ .. .. .
Y.....
Yb. ....... .....
Zn.... .....
Zr.........
0 0
.02
.04
0 0
0 .001
.002 .0004
.001
0
.0005
0 .008
.002 .0007
0 .0003
.001 0
.0001 .0004
.002 0
.4
.09
.1
.009
.002 .002
0 .0003
0
.01
.04
0004
0
0
.006
.002
0
0
.0003
.001
.002
0
.0008
.06
.002
0
.01
.0002
.03
.01
0
.0006
0
0
.003
.08
.0001
0
.01
.0007
.0006 .003
0
.01
0
.0004
0
.0003
0 .0006
.0001 .0009
.003 0
0 .5
.006 .03
0
0
0
.02
.002
.0001
0
.02
FIGURE 1. Photomicrograph of kyanite-quartz rock from Graves Mountain,
Lincoln County, Ga. Shows kyanite (k), fine-grained quartz (q), relict
phenocryst of blue (bq), a little muscovite( ?) (m), and rutile (r). Rock
is highly weathered and contains much limonite (1). Holes in section (h).
Crossed nicols.
and absent in coarse-grained foliated rock (fig. 3).
In some gneissic kyanite-quartz rock the layers of
kyanite are less uniform, and the crystals are not
so well oriented (fig. 4). In the occurrences just
Content of principal minerals, as calculated from chemical analyses
*
VB-W SY-87 NG-439 NG-440 f/
Sillimanite and andalusite. ......
52.6
43.7
l -Q2 "
63.3
27.0
" ".48"
8.66
61.9
37.0
".60"
53.8 1 -^t
43 . 1
1.46
K
8
.......... «C
Total. ..................
97.32
99.44
99.5
98.36 V
1 Includes about 4 percent topaz, as determined by point-counter method
of analysis of 6 thin sections.
Mode
NG-437
NG-437
40
3
40
17
and zircon
Total. ...................
Minor
100
FIGURE 2. Photomicrograph of kyanite quartzite from crest of Crowders
Mountain, Gaston County, N.C. Shows typical anhedral habit of much of
the kyanite (k) in the district. Opaque mineral is pyrite. Other minerals
are quartz (q) and limonite-stained white mica (m). Plane-polarized light.