Geology Reference
In-Depth Information
7.4
Using Figures 6.3 and 7.8a:
KCl:
8.3
Electroneg. difference = 2.4. 80%
ionic.
Garnet
Epidote
Pyroxene
Feldspar
Si
2.9909
3.0035
1.8589
9.5754
2.991
Al
IV
3.004
2.000
-
-
0.1411
6.3618
16.053
TiO
2
:
Electroneg. difference = 1.9. 65%
ionic.
Al
VI
1.6515
2.8055
0.0217
-
2.014
Ti
0.0321
-
3.044
0.0355
-
Fe(III)
0.3307
0.2389
0.0272
0.1157
MoS
2
:
Electroneg. difference = 0.4.
Mean electroneg. = 2.4.
Submetallic bond.
Fe(II)
0.2436
0.0266
0.6730
2.058
-
Mn
0.0419
0.005
0.0379
-
2.997
1.949
Mg
0.0876
0.0014
0.4312
-
Ca
2.6235
1.9205
0.7366
2.3799
Na
-
-
0.0952
1.4753
3.886
NiAs:
Electroneg. difference = 0.3.
Mean electroneg. = 2.1.
Submetallic bond.
K
-
-
-
0.0306
H
-
0.9548
0.955
-
-
8.4
Recalculate the molar proportions of the three
components to 100%:
per 6 oxygens
CaSO
4
:
(a) S-O bond: <20% ionic. Largely
covalent.
(b) Ca
2+
-(SO
4
)
2−
: more ionic.
100/1.9059
CaSO
4
.2H
2
O:
(a) Ca
2+
-H
2
O: ion-dipole
interaction (hydration).
(b) S-O: largely covalent as above.
(c) (Ca
2+
.2H
2
O)-(SO
4
)
2-
: ionic.
Ca
0.7366
38.65
Mg
0.4312
22.62
Fe
2+
+ Fe
3+
+ Mn
0.7381
38.72
Total
1.9059
100.00
Ca
Ca
Chapter 8
Diopside
Hedenbergite
8.1
Edenite
Z
8
O
22
, i.e. Z:O = 1:2.75; amphibole
(double chain silicate, Table 8.1).
Hedenbergite
Si
2
O
6
, i.e. Z:O = 1:3; single-chain
silicate (or perhaps a ring silicate).
Hedenbergite is a pyroxene.
Enstatite
Mg
Ferrosilite
Fe
3+
+ Fe
2+
+ Mn
Paragonite
Z
4
O
10
(OH)
2
i.e. Z:O = 1:2.5; sheet
silicate (mica).
The solid line encloses the
pyroxene quadrilateral,
where most pyroxene analyses would plot. (The
shaded areas show the range of pyroxene compo-
sitions found in gabbros. The two bands lie on
either side of a solvus.)
Leucite
(AlSi
2
O
6
) ≡ Z
3
0
6
, i.e. Z:O = 1:2;
framework silicate, i.e. fully
polymerized.
Acmite
Si
2
O
6
, i.e. Z:O = 1:3; single-chain
(or ring) silicate. Acmite is also a
pyroxene.
Chapter 9
8.2
Garnet
9.1
(a) Fe
2
(SO
4
)
3
+ FeS
2
→ 3FeSO
4
+ 2S
(b) CuFeS
2
+ 2Fe
2
(SO
4
)
3
→ CuSO
4
+ 5FeSO
4
+ 2S
(c) 12FeSO
4
+ 3O
2
+ 6H
2
O → 4Fe
2
(SO
4
)
3
+ 4Fe(OH)
3
(d) MnO
2
+ 4H
+
+ 2Fe
2+
→ Mn
2+
+ 2H
2
O + 2Fe
3+
(e) ZnS + 4Fe
2
(SO
4
)
3
+ 4H
2
O → ZnSO
4
+ 8FeSO
4
+
4H
2
SO
4
Si
17.99
Al
9.57
Ti
0.33
Fe(3)
3.97
Fe(2)
2.92
Mn
0.50
Mg
0.46
Chapter 10
Ca
22.58
O
41.27
99.60
10.1
(a) Be, F, Na, Al, P, Sc, Mn, Co, As, Y, Nb, Rh, Pr,
Tb, Ho, Tm, Au and Bi are monoisotopic.
(b) Tc, Pm, Po, At, Rn, Fr, Ra, Ac, Th, Pa and U
have no stable isotopes at all.
The difference in analysis total represents round-
ing errors.
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