ree geochemical characteristics of the two types of granitic rocks in jiangxi province and their...
TRANSCRIPT
Vol. 6 No. 2 GEOCHEMISTRY 1987
RISE Geochemical Characteristics of the Two Types of Granitic Rocks in Jiangxi Province and Their Metallogenic
Significance
SHEN JILI ( ~ 1 | ) AND LIu JIAYUAN(~qJ~j~) (Institute of Geoscience, yiangxi Province)
Abstract
Preliminary studies have shown that BEE geochemical characteristics are useful criteria to
discriminate the two types of granitic rocks in Jiangxi Province. They are aim of .i~ificant indication of
metMliT~tion. The principal REE geochemical indices are EREE, ECe/EY and 6Eu, as well as REE distribution
pattern. Each of the two types of granitic rocks has a metallogenic evolutionary series of its own with a
successive decrease in 6Eu. The application of REE geochemistry in the study of petrogenesis and ore genesis has been receiving
increasing attention. As will be shown in this paper, REE geochemical characteristics, especially YREE, V-Ce/YY, 6Eu and REE distribution pattern, are efficient indicators for distin~filhing between the two series of granitic rocks in Jiangxi, and thus enable us to have a better understanding :of the ore--formln~
processes in this region.
The Two Series of Granitic Rocks in Jiangxi Provinee
Two types of granitic rock - - crust type and transition type are widespread in Jiangxi and its adjacent areas, which are apparently different in source material and mechanism of genesis as well as in ore metallogenic specificity. (1) The crust-type granites, roughly comparable to the S- type granites of B.W.Chappell or the reworked granites of Xu Keqin, are considered to be responsible for the mineralizations of W, Sn, Nb, Ta, REE and U. Examples include metasomatic (migmatic) and intrusive granites of the pre-Caledonian and Caledonian Cycles, weakly acid to acid intrusive granites of the Hercynian-early Indosinian Cycle and acid to ultra-acid intrusive granites and a few granitic hypabyssal volcanic complexes of the late Indosinian-Yenshanian Cycle. With the exception of pre--Caledonian granites which are concentrated in the Jinning folded
zone in northern Jiangxi, granites of various ages after the Caledonian occur in Caledonian folded zones in central and southern Jiangxi. (2) The transition-type granites, which correspond in some
respects to the I-type or syntectic granites, are associated with Cu, Mo, Pb, Zn, Au, Ag mineralizations and porphyry W deposits (Genetically related porphyry sn deposits have also been
reported in adjacent areas.) Temporally, they are restricted b~tween late Indosinian and Yenshanian and spatially they are controlled by deep faults, occurring as small bodies in the order
of 1 km 2 along the faults. They are composed of hypabyssal subvolcanic porphyry, porphyrite and
buried explosion-elastic rocks of intermediate-acid to weak acid compositions (a few of them can be classified as intermediate or acid). A small number of these granitic rocks are medium- to free--
grained granite, granodiorite or quartz diorite with inequigranular or subporphyritic textures,
154 GEOCHEMISTRY Vol. 6
which were emplaced at greater depths. In view of their genetic relationship with synorogenic andesitic volcanism in this region, granitic rocks of .this type are referred to as granitic buried volcanic complex.
l t ~ Abundane~ in Different Types of Granite
Crust-type granites REE contents of whole-rock samples were measure d with a plasma spectrophotometer at the
Yichang Institute of Geology and Mineral Resources and the Institute of Rock and Mineral Analytical Techniques of the Ministry of Geology and Mineral Resources. The results are presented in Tables 1, 2 and 3. Generally, the determinations are of satisfactory quality, except for Pr and Tb which are found to be higher than reasonable values. The values.of Lu as given by the Institute of Rock and Mineral Analytical Techniques are of poor accuracy and are listed only for reference.
1. Metasomatic granites The. average REE content of the Jiuling cordierite--hiotite granodiorite is 168 ppm and that of the early Caledonian Cizhu plagioclase granite is 150 ppm.
2. Intrusive granites Based on 37 rumples from 16 granitic bodies (Table 1), the average
114" | 15 " 116" I 1 ~ 118" • , [ -
, ........... " ' . . ) :'~,.Anhui , ", Hubei -.~"~-~" d~, "-.-~ ~ - ""
t.~ir,, o Shangrao'
:, 'F
[ 34
114" |15" |16" 117" 11"8"
0 , s,o , 100 , k "
Fig. 1. The two series of granitic rocks in jinnwri and related W- arid Cu- melMliy~tion.
1. Cu, W--depoeils related to the ~ i t i o n - t y p e granites;
2. W deposits related to the crust-type granites;
3. transitiow-type granites associated with late Indosinian-Yenshanian melalliT~tions; 4. crust-type granites
associated with late Indosinian-Yenshanian metslli,Jtions; 5. pre-Indosinian crust-type granites (prior to
meta[li~tion).
T~
lt
I.
gE
E
gt~¢
hem
le~l
eh
~ae
ttrl
sti~
of
the
¢rra
sl-t
ypz
gras
~it~
ha
Jis
mg6
ti
Roc
k bo
dy
Age
R
ock
t)p
a
=,
y~-'
B
iotit
e gr
anit
e
Bio
tite
gra
nit
e
Xih
uash
an
Him
]re
gram
te
1'~
2 B
iotit
e gr
anit
e
~-~
B
iotit
e gr
anit
e
Dan
gpin
g [ X
enol
il],)
Hel
itlg
ylt~
G
ran
lt~
tl,l
rph
y r ~
Bio
tite
gram
te
y~
Tw
r~m
i,;a
gra
nite
Xia
olon
g M
usco
vite
gr
anit
e
Dac
ite
porp
llyr
iw
1 lac
lW-p
orph
yrit
e
),~-
t
Mon
z0lll
HC
gra
mtc
y~
~ M
u~co
wtv
gr
anite
Oa~
isha
n 6~
D
mr~
te
Dlo
r]le
Qn~
Q
uar
tz-p
orp
hv
r:
Mon
zonl
tlc
gran
tte
ltao
shan
7~
M
m,z
lmiti
c ~r
anlle
IQia
ncha
ng~
Bio
tite
gram
te
y2
t~
Bio
tite
~ran
tte
Tw
~lm
ca g
ran
ge
Bai
shlg
han
1'~ -
I~
~{tlS
l'°~l
le g
ralll
te
I't g
lmlu
tc
((ru
-t)
?~-I
}~l¢
,h [c
5~
a,i]t
,.
Hua
ngsg
a y~
- 2
Tw
u-na
Ka
gran
ite
y~
T~
o
mw
a gr
amte
(hm
ggus
han
a lh
orm
'
Yin
gqla
n 1~
M
otlz
onlll
t gr
anll
e
X la
mng
hng
i=~
(;ra
nit p
pD
rph}
r)
Hu
ken
g
)'~
3"~0
m
wa
grar
ntv
"['~
o tln
{d
gram
te
Dal
oltg
shan
}'~
lh
,,t i
t., I
~ral
llH
Xla
ng~h
an
Eu
;Mn
rtar
gra
nlt
t po
rph}
ry
y~
Mor
tar
rhy.
lit,
.
Tu
if
hk,"
,n[~
rtar
do
uh
,,'
29
~M
h2
32
0.3
5
25N
>
6.30
04
4)
Gra
mte
im
r]A
Q r>
39
23
1109
8 8,
18
t.1/7
7 6.
39
0.~
?~ -
L !
tlio
tite
gra
n,t
, 51
57
1220
1 11
55
52.0
5 12
.17
1.02
Qm
g~an
long
~han
. ?,
~-z
. B
iotin
- gr
alu~
e 53
.311
1
13
.64
12
86
-i58
8 9
71
1.
28
Anf
u ~
'zs-
2b
Tw
o m
ica
gram
tc
5631
12
257
1411
19
9 1
0.3
9
tl.07
Y~
t~
Porp
hyri
h¢
graf
t]t*
11
.03
27.3
2 49
3 11
12
3,71
0.
08
Zc~
gjia
kmg
"1'~
o m
wa
gran
d,,
I 79
5
20
0.
03
2 05
1.
04
0.~3
..~ -
is
Mu.
(,>
x lit-
gra
n,n'
I
78
1185
10
0 1.
79
17.3
0
gl
Cla
im
l'~
a P
lagl
l. l
a-v
gram
tc
1663
37
15
;.30
17
14
42
2
1.41
1
26 t
2 X
q.05
7.
95
2.05
5
61
0 91
(]or
dler
llo
hlol
lw
1688
U
)I 7
1 1
2.1
i 46
31
!07
i 0.
86
;d~
° gr
anod
mri
te
50.5
/I
I 1 ]
133
k3.3
7
04
1.
04
JnA
ing
(t;a
,~hu
) 26
311
57
7.30
25
.10
5.85
0
99
RE
E
Con
tent
(in
ppm
)
ca
o,
.o
Yb
Y
1 71
1 1
0.6
9
I/Y
) 9
12
, :t
06 i
8.
60
i.33
I 71
.25
21
7
12
.42
2
63
11
if8
12
8 4.
81~
IllD
17
4 85
.83
36
1
25.6
11
58
8
21
-2~
12
2.3
i 39
1 17
1.89
2,29
1
3.1
0
2.80
1
28
01
49
~,
]15
9 I
1
09
18
07
0
252
M,'u
~.,&
mau
, t~
o-t
un
a
1'~'
K
I,
'hhl
~ar
glam
l,"
la
Ce
Pr
Nd
Sm
46,3
2 54
8
.25
1
2.9
5
5.70
1,
43
6,11
4 24
3
32,7
9 44
.20
503
I 1 7
4
5.22
0,
80
9 96
24
2
65
7
23 5
9 2
.60
1
1.5
0
97
9
13
0
14.7
9 3L
~
3431
4-
$11
520
1229
5
49
08
1 10
30
1033
25
.21
3.7
8
1730
0
09
0
19
12
90
10
3
17
.96
4
98
9
90
!
1 62
14
87
] 87
12
139
256
81 2
4
I(d
3.1
17
9a'j
(~) 7
6 13
95
0 8-
1 9
6/
1.11
7.
35
182
3 63
{)
03
I (X
~ 0
30
4-I 6
5 11
1
,580
.3
7587
18
68
~06{
1 5.
45
1 73
8.
33
162
5.65
1
77
3.08
0
59
1,81
) 0
59
33 1
5 25
7
26.4
;)
59.6
6 8.
16
29"9
9
65
0.
16
8.82
2.
61
10
.45
2
27
7
50
l.O
0 9
99
1,
04
53C
}4
227
41 7
9
95
59
9.
35
45 3
3 6.
64
08
6
5.28
1.
8,5
6.09
1
,12
3.
39
4.74
4.
0-I
0 31
1 33
85
2(30
16.1
8 42
,68
6.08
23
.35
7.21
0
19
8.
33
2,98
12
.56
3 05
8
99
1.
42
8.81
1 10
6 93
09
237
18.7
6 40
12
1.97
18
13
34.5
0.
93
3.13
0.
71
2.62
0
64
1
.82
0,
24
1 76
0,
26
18,3
3 11
6
17 0
6 40
12
5 21
19
27
3.,t6
0.
98
3.20
0.
63
2.53
8
63
1 8
3
02
4
I 76
0.
25
1781
II
;
70.7
l)
16
3,7
0
19.8
6 00
12
.94
20
0
6.20
1
t0
4.60
1
14
3.15
0
35
2
50
0,
12
26 7
7 36
7
• i 20
5.
50
1 66
3.
86
36
0
0(17
5.
611
0.80
2.
10
0 13
0
.ll
0.02
0
03
00
7
I I
39
77
5
l$.5
1 3.
65
1198
31
,5
112
3.99
0
77
4
10
0
90
2.
80
0.10
2.
k5
O14
21
.26
80
1361
38
3~1
6.46
t8
.82
58
7
13~
5.
03
1.19
t.
70
131
33
2
0.60
8.
08
07
7
27.5
fi
137
38 4
0 66
.60
10
.76
18
.86
95
0
1.30
8
00
I/,~
l 7/
XI
2,20
6.
30
1,0
5
ZO
O
1 05
55
.10
266
63
99
1
27
.9
~1
.30
7
r4"7
3
14.9
,3
0.98
1t
.34
1.70
14
,18
37
6
6.96
11
5 8.
37
0,01
80
.70
.109
2994
60
68
60
5
2797
~
&i
0.~
1
10.8
3 1.
29
11
.71
3.
22
6.02
0
97
7
37
0
80
69
,36
2]6
1627
3
t69
4.
22
18
.32
6
98
0
ll
00
8
1.36
13
41
3.77
72
1 ].
14
94,3
l.
ll
9235
22
1
~,62
5 1
21
.61
1
3.9
2
48.1
6'
1142
0.
8,3
0.78
1.
12
7,75
2
02
4.
57
06
0
39
7
0.23
4a
).20
32
1
1232
2~
47
38
7
15.8
5 6
88
0.
18
73
3
1.09
9.
26
2.28
16
9 0
79
7
1~
4
0.B
0
58
36
16
1
5.19
12
26
165
56
8
20
4
0 13
1
91
0.33
2.
36
0.60
1.
36
0.22
1.
95
1377
50
;.7:i
10
,41
1
4.5
;.c~
1.
83
0.15
18
1t
0.33
1.
94
0.50
1
04
0.
18
1 87
0.
04
1033
'tl
2111
12
k327
59
~
22.0
3 8,
28
0.27
9.
37
1.t,5
1
2.1
0
33
2
64
8
1.08
9
33
1.27
82
02
228
1253
30
02
305
1176
6.
35
01
1
64,6
1,
00
8.28
2.
04
41
3
D.7
9
8.08
11
8 51
53
15l
15,3
6 37
711
546
21.5
0 10
.90
0,25
17
98
3.02
31
1.67
8.
93
t8.3
5 22
)'6
27,3
t 3,
89
218.
1,3
423
13 0
2 32
.lq
,I
n2
18.9
3 4.
75
2,31
4.
6.3
0.50
3
61
0.9t
2,
39
0.28
1
~q
1611
5 10
7
3181
1 63
63
735
2807
6,
26
14
3
5.11
0.
55
3.89
1.
It8
23
8
0.38
2
24
--
20
42
175
I..57
7 31
79
119
164"
5 5.
07
0.39
6
11
0
80
6
99
1
.82
10
7 0.
5~
k81
02
9
1201
11
2
1115
1 2
5t1
7
333
1248
5 5.
85
0.22
6.
05
07
6
6.16
19
"1
28
11
0
35
2
68
35
.18
111
9 T
l 2,
118
335
1.10
6 7.
11
01
6
9.97
I
55
I 13
.85
3,68
11
16
112
9.73
12
1 9
63
7
2111
1083
28
.2ti
t R
) 19
58
0.97
8
19
1,1
ll
22
5
2140
6
20
14
51
2.13
20
.29
27
5
15t.8
9 31
2
('48
0 I'
ll 4
5 1
-18
9
4448
8.
29
1.02
5.
55
1 76
4,
14
102
28
7
04
9
2 19
0
38
24
.f14
30
8
.18
60
¢Y9 8
~ I I
6(:
35 9
2 7.
N)
0.73
5
20
19
5 k
45
1 1
5
3 05
0
55
2
65
0
40
2631
25
0
5.30
2.
04
5.05
1.
38
3.85
0
59
3
25
01
8
29.9
2 18
0
5.37
19
3 7
84
1.
31
3.75
(!
,57
,1
57
01
5
44.0
0 29
1
7.92
0.
89
46
9
1 13
3.
35
03.1
I
28
1839
29
1
7.03
0.
9,~
5.52
1
,48
4
.01
0
50
2,
53
0.02
26
.38
287
5 8.
3 0
67
3.
24
11.8
3 2.
85
0.31
1.
02
1196
28
1
3.65
1.
21
6 ll
1
t6
4.5
'3
11.6
9 t9
2
05
9
37
20
1i
9
1.11
4 0.
11
14".
8 0
.31
0.
73
Oll
0.
62
01(I
7.
56
24
1.7.
1 0.
~)
2 53
0.
42
1,05
0
16
0
84
8
04
110.
3 44
3.71
0.
45
23
4
0.61
1,
41
02
3
0 75
--
9
41
150
1.86
1.
36
50
5
1.13
3,
-t0
0t6
2.
01
0.4"
3 26
78
147
Par
amet
era
~ppm
)£REE
Z
Cc
/ZY
[ L
a,'.Y
h 0E
u
1.60
5
0`82
0.70
3
03
8
0 20
0.
80
0.37
0.(~
3
0 37
0 35
/)
70
0 06
k62
20
0 22
3,gO
,/2
0.
88
1.31
2
16
0
06
3.28
10
.40
0.47
0.61
3 1.
84
0118
2.98
10
.7
0.92
3.02
9.
7 i1
.98
6.86
2
09
0.
61
0.95
14
0 0.
05
1.1.
1 3
2
1.02
1.60
1
70
0.82
1.93
5
5
04
9
20
7
76/3
0.
23
1.22
0.
70
0.23
05
8
1.70
0.
17
36
t 14
10
02
7
0,74
1.
60
0013
I,I 2
2,
80
0.22
1 33
3.
50
/).2
7
0.81
1 2.
10
0.10
0.81
1,
60
0,06
0.27
0`
~1
0,0~
21
9
92
0
1.6"
3
3.83
1,
3 0.
82
1.10
3.
3 (/
,22
1 93
7
10
0
35
OA
O
02
0
0.07
0.31
t .
(~1
0.05
6,11
2
96
0
04
7
4.47
18
,80
0 36
2.58
0.
20
02
6
30
6
8(~
) 0.
36
6.75
43
1
0 32
4,94
21
,9
OA
9
9.53
55
,00
0 35
0.91
2.
1 0.
04
0,95
2.
9 0
t4
1.37
5.
7 0
08
4.28
t0
.8
1.18
21
8
94
1t
.57
CaO
%
DI
1.19
87
0.60
87
11.5
7 92
07
9
92
O 4
4 93
8.33
89
0.6t
9
l
30
3
2.04
73
0.35
94
1.51
77
1.00
g8
1.38
93
1.13
09
0.3B
88
0.38
88
.
0 73
9,
t
07
3
93
.113
70
o.60
95
(!.4
;4
92
0 49
92
04
9
92
1.;3
9 88
1 22
89
08
2
91
1.89
81
7 24
0.
77
k3
1
102
]98
0.
33
1 24
17
43
253
6.39
5.36
0,
97
;07
0
.BI
22
8
1140
--
0
32
2
03
26
1 6
62
48-I
0.
92
,1.9
0
0.93
2
6.1-
0
4"5
- 0.
39
247C
l 16
2 3
08
~,8
1151
2
65
6.
16
2.07
0.
08
20
0
87
0
2.%
0
,71
2.
10
i 0.
33
23
7
03
2
1811
61
I(
~
9~.1
11
87
1 f~
rl 5.
93
2.05
0.
20
2,80
0.
17
2 72
0
60
1.
53
0.30
2
02
0.34
15
08
:56
1.23
I
0,44
89
- 93
0.57
91
4.[
l 58
1.76
70
37.8
0
30
. 1.
02
77
0.50
" 1.
88
76
--
061
2.00
72
2.4
01
3
0.89
79
4.60
0`
32
--
--
Sam
ple
Age
loca
lity
5ini
an
Wug
ongs
han
5ong
shan
grou
p
Ciz
hu
~ini
an
Pre
-Sin
ian
Shu
ang-
Yan
geh~
ding
i
qiao
shan
Gro
up
Bai
shis
han
$in
ian
-
Dal
Gng
shan
C
ambr
ian
Roc
k ty
pe
Str
eak
y~
cula
r m
igm
afit
e
Gne
issi
c tw
o-m
ica
gran
ite
Str
eaky
mig
mat
ite
Mig
mat
itic
gne
iss
Slat
e Pi
~olit
ir
tuff
Silty
sl
ate
Sand
y sl
ate
Tab
le 2
. R
EE
ge
oche
mic
al
ehav
lete
rllf
iel
af m
[grr
.atlt
e an
d m
etam
arph
it
~mks
in
Jiim
gxi
La
Ce
51.3
3 10
1.74
15.4
5 34
.76
39.5
2 79
.73
!58.
90
125,
38
11/1
3 87
.69
42.6
6 95
.23
34.0
8 70
.68
37,2
4 81
.19
RE
E
Con
tent
(i
n pp
m)
Pr
Nd
Sm
Eu
Gd
Th
D~
Flo
E
r
11.5
2 40
.61
9.27
1.
35
8.23
1.
13
8,19
2
.37
' 6.
00
4.18
15
.71
4.10
0,
53
3.29
0.
41
2.26
0.
54
1.24
9.12
33
.94
7,48
1,
67
6.26
0,
85
5.33
1.
59
3.99
14.0
1 53
.02
12.0
9 2.
04
10.1
2 1,
34
8.77
2.
53
6.48
q.53
37
.23
8.41
1.
80
7.38
0.
87
6,69
1.
89
4.28
10.b
i 1,
2.74
9.
95
1.82
8.
90
1.05
8.
06
2.23
4
.84
Tm
Y
b
0.69
4,
19
0.18
0.
73
0.57
3.
10
0.85
5.
12
0.66
1,
.13
0.71
, 4.
61
Lu
Y
0.22
45
.35
- 10
.12
0,13
28
.19
0.25
4,
5.36
O.O
q 35
.24
0.13
4
2.4
,3
7.94
31
.42
7.05
1.
39
6.28
0.
75
5.25
1.
46
3.05
0.
4,3
2,59
0.
03
27,2
6
8.85
34
.(]6
7.
67
1.38
6.
70
0.80
5.
95
1.69
5.
51
0,60
3.
34
0.15
31
.89
Ave
rage
Par
amet
er
YR
EE
E
Ce/
EY
I.
a/Y
b
(ppm
) 29
2 2.
82
12.3
93
3.99
21
.8
I 22
1 3.
43
12.8
346
3.28
11
.50
248
3.05
10
276
2.78
9.
3
200
3.24
13
225
3.12
11
.20
238
3.21
12
.73
6Eu
0.51
0.47
0,79
0.56
0.75
0£
4
0.87
0.63
0.65
Tab
le ~
. R
EE
ge
oche
mic
al
char
acte
rist
ics
of t
he
tran
siti
on
type
8r
anit
ie
rock
s in
Ji
angx
i
Roc
k bo
dy
Ton
gcha
ng
Shiz
itou,
Y
ongp
ing
Rac
k ly
pe
'Gra
nodi
orite
po
rph~
ry
Mon
zoni
tic
gran
ite
Mon
zoni
tie
gran
ite
Gra
nite
por
phyr
y
Dac
he
porp
hyri
le
Yin
shan
Q
uart
z po
rphy
ry
Fen
glin
G
rani
te p
orph
yry
Qua
rtz
dior
ite
Yan
gehu
ling
G
rano
dinr
ite
Gra
nodi
orite
po
rphy
ry
RE
E C
onte
nt
(in
ppm
) P
aram
eter
I
' Z
RE
E
,Y, C
e/X
Y
La/
Yb
6Eu
CaO
%
DI
La
Ce
Pr
Nd
Sm
~.u
Gd
Tb
DI
tto
Er
Tm
Y
b L
u Y
(p
pm)
13.6
,4
21.9
8 3
4,3
10.2
9 1.
~1
0.54
1.
21
0.24
1.
05
0.22
0,
68
0.12
0.
61
0.08
5.
04
61
5.59
22
.4
1.15
4.
02
66
28.1
4 61
.46
6.95
26
.52
4.92
1.
04
2.86
0.
58
1.92
0.
38
0.87
0.
17
0.59
0.
09
7.4
144
8.68
47
.7
0.84
2.
03
76
30.0
8 64
.96
6.72
24
.19
5.04
1.
19
3.52
0.
41
2.26
0.
58
1.61
0.
23
0.74
--
8.
86
150
7.26
41
0.
89
2.03
76
54.5
7 10
5.85
11
.59
34.2
2 6.
22
1.12
3.
12
0.94
2.
27
0.77
1,
57
0.28
1.
32
0.21
11
,5
225
9.71
41
0.
75
--
--
• 1,1
.36
73.7
8 7,
40
26.8
2 4.
96
1.34
3.
60
0.38
2.
56
0.67
1.
49
0.27
1.
21
--
12.1
5 17
8 6,
97
34.2
1.
00
4.06
61
38.6
70
.03
7.37
24
.81
4.68
1.
83
3.48
0,
45
2.65
0.
62
1.73
0.
21
0.94
9.
26
167
7.62
41
.4
1.45
0.
50
61
26.7
7 54
.97
5.69
18
.93
3,93
"0
.79
2.75
0.
34
2,17
0.
59
1.78
0.
21
1.24
--
10
.83
131
5.58
21
.5
0.76
--
--
22.1
7 49
.5
6.13
20
.5
4.32
0.
82
2.60
0.
71
2.53
0.
43
1.05
0.
19
0,84
0.
11
7.87
12
0 6`
33
26.4
0,
74
4.29
62
26.4
52
.1
11.6
29
5
6
1.2
5.8
0.6,
0 3.
10
0.8
0
1.80
0.
60
1.70
0.
35
16.5
15
7 4.
03
15.5
0.
70
2.80
74
15.5
4 36
.88
4.80
20
.8
4.20
0.
88
3.22
0.
6,3
2.23
0.
41
0.94
0.
16
0.71
0.
09
8.51
14
8 4.
92
21.9
0.
77
2.70
74
Hua
ngga
ngsh
an
Plag
iocl
ase
gran
ite
Hon
gsha
n po
rphy
r)
Frag
men
ts
of t
he s
ame
eom
pos
ition
Gra
nodi
orite
po
rphv
r)
Che
ngm
ensh
an
Wus
han
Yan
gjis
han
Lux
ilin
g
Mon
zoni
tic
gran
ite
porp
hyry
25
.60
50.5
0 9,
90
27.4
5
1,1
5.70
0.
60
2.80
0.
80
1.4.
O
0.55
1.
20
0.30
14
.00
147
4.37
21
.2
0.70
2.
50
77
:
Mon
zoni
tic
gran
ite
porp
hyry
17
.90
37.5
0 5.
96
17.9
6 4A
9 0.
74
2.78
0,
65
2,53
0.
58
1.40
0.
32
1.58
0.
24
12.6
0 10
7 3.
72
11.4
0 0.
64
2.10
--
,
27.4
5 53
.28
5.59
19
.98
3.83
0.
85
2.74
0
39
2.
87
0.85
2.
46
0.31
2.
14
--
16.9
14
0 3.
87
12.8
0.
83
0.35
33.3
7 64
.10
6.93
24
.6
4.83
1.
t0
3.50
0.
43
30
5
0.85
2.
54
0.29
2.
00
---
16.5
6 16
4 4.
62
16
70
0.
85
0.35
68
23.8
.3
76.1
0 6.
29
17.1
5 3.
80
0.8,
3 2.
26
0.56
1.
92
0.45
1.
22
0.02
3 1.
14
0.16
9.
.16
115
5.70
20
.9
0,1M
¢3
,42
(:~
Qua
rtz
porp
h)ry
6.
14
14.5
3.
81
6.86
2
59
0.
41
2.00
0.
84
2.53
0.
63
1.83
0.
41
2.81
0.
30
14.1
7 60
1.
34
2.18
0.
58
0.82
8
6
Qua
rtz
dior
ite
porp
hyri
tc
32.8
3 10
9.25
13
,24
.1;!
,.47
7.94
2.
06
5.22
1.
10
"3.3
2 0.
97
1,91
0.
18
1.23
0.
16
17.3
4 26
1 7.
35
43
1.00
3.
22
69
Gra
nudi
orite
po
rphy
ry
40.9
3 76
.82
9.93
27
.37
4.92
1.
0¢
2.95
0,
85
1.74
0.
35
1.14
0.
25
0,80
0.
14
10.2
4 18
0 8.
72
5I
0.83
3,
22
69
Gra
n~ti
urit
e p
orp
hy
~
47.7
5 89
.63
10.8
4 31
.65
5,35
1.
24
:347
0.
94
2.C
()
0.45
1,
32
0,21
0.
94
0.1
7
11.5
0 22
8 8.
87
50.8
0.
89
3,22
Gra
nadi
orit
e po
rphy
ry
34.1
1 68
.29
8.28
37
.65
5.53
1
12
2.
95
0.49
2.
26
0,45
1.
f15
f).1
7 0.
97
0.12
%
72
!58
9.,5
,8
35.2
0 0.
83
3.59
6
7
1 4.
34
0~85
"
Qua
rtz
dior
ite
po-p
hyri
te
I 3
07
63
.17
8.44
23
.95
4A5
0.93
2.
95
1.59
2.
27
0.fs
'~
1.75
0.
30
1.40
0.
23
15.7
5 15
9 4.
90
21.9
0 0.
84
3.52
6
7
porp
hy-y
'
49
A,5
99
.02
"~i)
,92
41.0
6 5.
79
t 1.
56
3.31
0.
59
1.57
0.
24
1.47
0.
22
17.3
2 22
3 6.
95
33.6
0 0
98
3.
14
74
G
rann
d.or
ite
!
REE content of intrusive granites (excluding intermediate-basic dyke~ and pegmatites) is 225 ppm, apparently higher than that of metasomatie granites tx] but lower than that of pre--Sinian- Cambrian migmatite and metamorphic rocks in Jiangxi (241 ppm, Table 2).
TransiLion-type granites Based on 22 samples from 11 granitic bodies (Table 3), the average REE content of the
transition-type granites is 156 ppm, which is obviously lower than that of the crust-type granites but higher than the value of 93 ppm as given by Yu A. Ba3p-qhov and A.I.Tngarinov (1978) for island arc andesite [1]. Detailed study has revealed that among the crust-type granites the early metasomatie granites originated through anatexis-metasomatism from a series of low-grade metamorphic rocks with intercalations of metamorphic spilite-quartz keratophyry. This accounts for their low BEE contents as compared with the crust-type intrusive granites, indicating, to a certain extent, a common magmatic source for the two types (crust and transition) of granites.
REE Distrilmtion Patterns
10(
Five distinct REE distribution patterns can be recognized in 71 samples from 30 granite bodies representative of the two series:
1. Patterns with positive Eu anomalies Characterized by a right-hand dipping curve in the chondrite--normalised plot with 6Eu > 1. Examples are the Tongchang granodiorite--porphyry and the Yinshan quart~porphyry of the transition-type and, among the crust-type granites, the Cizhu plagioclase granite and the diorite dyke in the outer contact zone of the Ganggusl, an ore-- bearing granite (Fig.2).
. !
2
t .o
~ 211
\ 1 5
5
o 20
* t ! t s I . • • t
La Ce I)rfid SmEuGdTbDyHoErTmYb l~u
Fig. 2. Fig. 2. BEE distribution pattern in the Tongchtn$ granodiorite porphyry.
No.2 GEOCHEM~TRY 1~
1 l.aCe d SmEuGdTI)Dy I|,)ErTmY5 I.u
F ~ . 3 . REE distribution patterns in granitic /ocks from the Yinshan rock body. 1. Quartz porphyry; 2. dacite porphyrite.
2. Patterns without Eu anomalies Also characterized by a fight-hand dipping curve with 6Eu = 1. Examples are the Wushan quartz diorite porphyrite and the Yinshan dacite porphyrite of the transition-type and some later intermediate-basic dykes derived from the crust-type,granites (Fig.3).
156 GEOCHEMISTRY Vol. 6
3. Patterns with small negative Eu anomalies Similar to the above patterns except for a
shallow V-valley at Eu. 6Eu ffi 0 . 7 0 - 0.96. Among the transition-type granites, rocks of all
intrusive phases in the Yangchuling complex, the porphyritic biotite monzonitic granit~ at
Shizitou, Yongping, granodiorite porphries at Wushan and Chengmenshan and the medium-
grained porphyritic biotite amphibole monzonitic granites at Yingqian are examples (see Fig.6).
,°° l so~- 3u[-
| J a I a ~ i a ! l I I I I
1 La Ce Pr Nd Sm Eu Tb Ho ErYb Lu
Fig. 4. REE distribution patterns in granitic rocks from the Fenglin and Hongshan rock bodies.
1. Fenglin granite porphyry; 2. Hongshan plagioclase granite porphyry.
4. Patterns with moderate negative Eu anomalies 6Eu ranges from 0.4 to 0.7, as
recognized in the crnst-type granites from Xiangshan, Qingwanlongshan and Jiuling (Figs.5 and
6).
I00
"".%..
• " ' """ ............. 3
• Z ,~...~-~.~ .-
,50 q~
3O
g 211 e~
1,5 \
8
n t i I I I t | • I s t i.
I Ls Ce Pr Nd Sm Eu Ld I)y !1o ErTmgb Lu
F i g . 5 . BEE distribution patterns in granitic rocks from the ~ian~,shan rock body.
1. Granite porphyry in the inner gone; 2. mortar rhyolite in the transitional gone; &
m a r g o t ] g o n e .
tuff-like rhyolite in the
5. Patterns with maximum negative Eu anomalies Characterized by a nearly horizontal
REE curve with a very deep valley at Eu (6Eu < 0.4). Two cases may be encountered. In one case
the curve is slightly left-hand dipping, with ~Ce/Y~Y being less than unity. Examples are
medium- to fine-grained porphyritic biotite granites at Xihuashan and Dangping, two-mica
No.2 GEOCHEMISTRY 1~
Fig. 6.
100
® 50
15; \ . , 'd
c~ 5
• . . . . . , , . . :
/ A * .
- - - " - ~ s.... x...._,. ~ x ' l
L* Ce d SmEuGd D>' r Yb Lu
REE distribution patterns in granitic rocks from the Ji,dln s rock body.
1. Cordierite biotite granodiorite; 2. Gaohu metammatic tivo-mica K-feldspar granite.
granites at Ganggushan, biotite granites at Dalongshan, etc. (Fig.7). In the other case, the curve is
slightly right-hand dipping, as shown by fine-grained porphyritic biotite granites at Baoshan, Xiatongling and Baishishan and porphyritic biotite granites at Zengjialong (Fig.8).
50
30 " / ~ 2
o ,~ ~ . . - - ~ ' , , /"" . 1
\ - I~ ,'/
] t ~ J I I I I I I I I
1.* Ce Nd SmEuGd DF Er: YbLu
Fig. 7. REE distribution patterns in granitic rocks from the Ganggushan and Xiatongling rock bodies.
1. Xiatongling granite porphyry; 2. Ganggushan two-mica granite.
5O QJ
• E 3o
~ 20 0
\
¥ 5
S ' " * " * " z s , t A
i l ....... ,
',iI
* ' d , , i I I I I La Ce N S m E u G d DY I~r Y b L u
Fig. 8. REE distribution patterns in granitic rocks from the ore-bearing complex at Zen~ialong.
L Two-mica granite; 2. porphyritic biotite granite; 3. muscovite granite.
158 GEOCHEMISTRY Vol. 6
In general, the first three patterns, i.e., those with positive or no or small negative Eu anomalies, are typical of the transition-type granites. But exceptions can be cited with respect to some individual rock bodies which are more acid petrochemieally, such as the quartz porphyry at Chengmcnshan, and may show REE distribution patterns with moderate negative Eu anomalies. On the other hand, REE distribution patterns in the crust-type granites are mostly characterized by maximum or moderate negative Eu anomalies, and nearly all ore--bearing granites show maximum negative Eu anomalies. Small negative, or even positive, Eu anomalies, however, are reported from a few metasomatic granites prior to the early Caledonian Cycle. Additionally, intermediate-basic dykes derived from intrusive granites at the later stages of development always exhibit weak negative to positive Eu anomalies but their ~-Ce / ~Y ratios are lower than those in the transition-type granites. $'nniIarities in REE distribution patterns between metasomatic granites
and intermediate-basic dykes on one hand and the transition-type granites on the other provide further evidence suggesting that these rocks may be correlated with respect to their source magmas. Wang l.iAnkui et al. held that the occurrence of intermediate-basic dykes as the final products of magmatic differentiation strongly indicates the incorporation of mantle materials during the formation of remelting granites in the crust. This view has found further support from the REE patterns in intermediate-basic dykes associated with the crust-type granites.
RF~ Frnctlomttion Amoehtted with Magma Differentiation of (~-8nitoid Rocks
1. The results show that with their ages changing from old to young granites of the crust type become more and more acid petrocbemica]ly, accompanied by an increasing average REE
content (from 163 to 224 ppm) and decreasing 6Eu and Y~Ce/Y~Y (Table 1). 2. For a given differentiated complex, the acidity increases with successive intrusion. In
terms of REE fractionation, early intrusions show high REE contents and 6Eu and are rich in the Ce group while late intrusions, on the other hand, tend to become low in REE and 6Eu and more Y-rich. As can be seen from Table 1, this is the case for the differentiated complexes at Dajishan, Dangping, Huangsha, Baishishan and Zengjialong. Taking Dajishan as an example, the early intrusion, the Wuliting biotite monzonitic granite, is weakly acid and contsin~ 366 ppm REE with %Ce/I:Y = 6.86 and 6Eu -- 0.61 while the late intrusive muscovite granite contains 39ppm REE with I:Ce/~Y = 0.95 and 6Eu = 0.05 all of these parameters decreasing regularly. This evolution trend will be reversed in the case of alkali-feldspathization. For instance, a norn~al evolution is reflected by variations in REE content from 321 through 160 (49) to 41 ppm, corresponding to an early to late intrusion succession of porphyritic biotite granite .* two-mica (or muscovite) granite .* pegnmtite in the Baishi Complex. However, in muscovite granites which show varying extent of alkali-feldspathization and in K-feldspar-rich pegmatites, an inverse relationship can be noticed with respect to ~ECe/~Y and 6Eu: :~Ce / ~Y 3.64 .* 0.74 (1.12) .* 1.34 and 5Eu 0.27-*0.08 (0.22).*0.27. This is consistent with the conclusion reached by D.H.M.Alderton from his study on the mobility of BEE during alteration of granitic rocks that as shown by alterations producing K--silicates, slight depletion could be recognized in all REE except Eu. Similar trend was observed in the late Yenshanian Zengjialong Complex which is genetically related to Sn mineralization.
3.. As a result of in-situ magma differentiation, the various facies developed are characterized by increasing acidity and decreasing grain-size toward the outer parts of the
Nm2 GEOCHEMISTRY 1 ~
intrusive. Systematic variations can also be recognized in BEE geochemistry with such petrological changes. As shown by the Xiangshan mass, from the inner to the outer pa~ts four facies can be distinpdshed, which are represented respectively by granite porphyry - , mortar granite porphyry - , mortar rhyolite - , tuff-like mortar rhyolite. Petrologically, the contents of plagioclase and its An (No.) decrease, quartz increases, biotite decreases, and the differentiation index changes from 88 through 89 to 91 in going from the inner to the outer parts, demonstrating an increasing acidity. Y REE varies from 308- ,250- ,186 ppm; Y Ce/ZY, 6.11-,4.47-,2.58; ~Eu, 0.47-,0.36
--~ 0.26, all showing a systematic trend of decrease. However, an opposite trend has been observed at Baoshan where the rock mass, genetically related to the skarn-type scheelite deposits, is in direct contact with middle Carboniferous limestones. Assimilation and contamination with the limestones resulted in an inward increase in acidity, as reflected by the variation of differentiation index from the outer to the inner parts: 77 - , 88 - , 93, paralleled by a synchronous inward decrease in REE geochemical parameters: ZREE 411 - , 246 - , 221 ppm, YCe/ZY 2.07 - , 1.22 - , 0.58, and ~Eu 0.23 - , 0.23 -* 0.17. This indicates that magmatic assimilation and contamination could lead to more or less REE fractionation, with ZREE, ZCe/ZY and JEu decreasing with increasing
acidity. 4. Similarities between the pre-Sinian Shuangqiaoshan Group and the Sinian mignmtite and
metamorphic rocks in REE pattern (Figs.9 and 10), average REE content, Y-Ce/ZY and t~Eu (Table 2) indicate that at the stage of mignmtizatidn REE generally kept stable without apparent mobilization and migration. REE fractionation could only occur and develop when mignmtization reached the stage at which remelting granitic magnm was generated, followed by its differentiation. As expected, apparent differences can he seen in REE pattern between the Cizhu plagioclase granite and the surrou,ding early Palaeozoic mignmtites and between the Jiuling eordierite biotite granodiorite and the metamorphic rocks of the Shnangqiaoshan Group {Figs.6 and 9). Moreover, such differences tend to become increasingly obvious with differentiation. For example, as compared with the early granodiorite and the metamorphic rocks of the Shuangqiaoshan Grolup, the late metasomatic two-mica K-feldspar granite in the Jiuling mass (Fig.6, Gaohu-7~ 2c) exhibits a
1001
50~
3 0 =
20i
\ 4
3
_ i i a . i I i | i • • I l i i
La Ce Nd Sm-Eu"Gd Dy Er Yb Lu
Fi~. 9. REE distribution patterns in metamorphic rocks.
I. Slate around the Yan~cb.lin~ rock body; 2. pisolitic tuff around the Yangch.lln~ rock body;
3. metamorphic wan rocks ill the ~ minin~ district; 4. metamorphic wall rocks in the Dalongshan
mining district.
160 GEOCHEMISTRY Vol. 6
remarkable difference in REE pattern. Such a trend strongly suggests that in terms of REE
geochemical characteristics, granites may be quite different, while having some heritages, from
their source rocks.
lr~g. 10.
100
50
• ~ 30 g 20 e .
\ 1 5
g ~ 5
• ,. ,,..,,-,.. %
I | t I I I I t * t I a t •
LaCe Nd SmEuGd Dy Er YbLu
REE distribution patterns in the migmatite and metasomatic granites at Cizhu.
1. Plagioclase granite; 2. migmatitic gneiss; 3. streaky migmatite.
Chart, for ~ h l n g between the Two Series of Granite,
h is evident from the previous discussion that the two series of granites in Jiangxi are apparently different in REE geochemistry. A few charts are presented here by which the two series
of granites can be distinguished from each other on the basis of BEE data. 1. 6Eu-CaO chart As shown in Fig.11, the transition-type granites have, in most cases, a
CaO content of more than 2% and a 8Eu value in excess of 0.70. In contrast, the crust-type granites are characterized by less < 2% CaO and 6Eu between 0.05 and 0.70 (mostly less than 0.4).
To a first approximation, therefore, a Ca(} content of 2% and a 6Eu value of 0.70 can be used as threshold values between the two series of granites. As for the metasomatic granites of the crust type, some of them, such as those at Jiuling and Wugongshan, can be distinguished in this way, but others, which are similar to the transition-type granites, such as the Cizhu mass, should be
classified by other approaches. 2. ZREE-La/Yb chart It is apparent from Fig.12 that REE contents of nearly all the
transition-type granites are lower than 200 ppm, and that La is enriched relative to Yb with La / Yb
ratios greater than 5. On the other hand, the crust-type granites, except for a few metasomatic rock
bodies and complexes which are associated with W, Sn, Nb and Ta mineralizations, usually contain
more than 200 ppm REE and are characterized by the enrichment of Yb relative to La, with La / Yb
ratios varying over a wide range (generally < 5). The intermediate-basic dykes are similar to the
transition-type granites, but can be distinguished from the latter by their geological occurrence,
especially their close spatial association with intrusive granites of the crust type. 3. ZREE-6Eu chart As can be seen from Fig.]3, the transition-type granites are generally
low in YREE but high in 6Eu whereas the crust-type granites are high in ZREE but low in 6Eu. If YREE of 200 ppm and 6Eu of 0.7 are chosen as the boundary, a large number of granites can be
assigned to one or the other series in the twofold division. However, overlaps are noticed in some cases. Some metasomatic granites, the biotite granites associated with ion-adsorption-type REE
No.2 GEOCHEMISTRY 161
Fig. 11.
0 b E u 1 .2 o ~,
II e • * e
0 . 9 : o o ~ -e e ® : . . ° e - . \ e e o
® \
o. =. . "~~. o \
o o o o o I \ o O
o. ° : o o , o " \ Oo ° ° ° ° ol . e 2
• 13 04 o 5
o ~ & ° , , , ,
0 1 2 3 4 CaO (%)
Correlation between ~Eu and CaO in the two series of granites in Jiangxi.
I. Crust-type granites; II. transition-type granites.
l. Granites related to W, Sn, Nb, Ta.minerali,~tions;
2. intermediate-basic dykes; 3. metasomatic granites;
4. granites associated with porphyry W mineralization;
5. granites assoeiat,~l with porphyry Cu, Au, Mo mineralizations.
Fig. 12.
L a / Y b o • ~ e o ~ o o D ° • • 0 50 • - ~o • •
25 . • ~'e,'S, J o o o
;0 ~,~',~ "o./~(.o., o o o
ol • / 00 • 5
%1 II o °~ °- o o°
O
V ° , , , , , ZmREE ppm
20 80 140 200 260 320 380- 440
o l e 2 e 3 $ 4 e 5 *6 Correlation between ~REE and La/Yb in the two series of granites in J;an~i.
I. Crust-type granites; II. transition-type granites.
1. Granites related to W, Sn, Nb, Ta mineralizations;
2. intermediate-basic dykes; 3. metasomatic granites;
4. low-grade metamorphic rocks;
5. granites associated with porphyry W mineralization;
6. granites associated with porphyry Cu, Au, Mo mineraliTJtions.
GEOCHEMISTRY Vol. 6
1"2I e • •
0.9
0.6
0.3
e e• o l II 'b " e2
®la • o • 3 ~i e 4
, 5 t6
, t t o m m • •
.
o I ~o 0 m o o
o ~'J o o
o oo e~' o PPm
100 200 300400 ~ R E E
Fig. 13. Correlation between I:REE and 6Eu in the two series of granites in Jiangxi.
I. Crust-type granites; II. transition-type granites.
1. Granites related to W, Sn, Nb, Ta mineralizations;
2. intermediate-basic dykes; 3. metasonmtic granites;
4. granites associated with porphyry W minerMi~tion;
5. granites associated with porphyry Cu, Au, Mo mineralizations;
6. low--grade metamorphic rocks.
deposits and intermediate-basic dykes derived from the crust-type granites may plot into the area of the transition-type granites. Similarly, few rock bodies of the transition-type granites may have I~REE greater than 200 ppm and a 6Eu value below 0.70 falling into the area of the crust-type granites.
4. 6Eu-DI chart For the transition-type granites, DI, in most cases, ranges from 60 to 80 and 6Eu from 0.70--1.2 while for the crust-type granites DI generally varies between 80 and 94 and 6Eu is less than 0.70 (Fig.14). Therefore, the two series of granites can be separated on a 6Eu vs. DI chart with reference to the line passing through DI = 80 and 6Eu = 0.7. Such an inverse correlation between 6Eu and DI is in agreement with the conclusion of Forbes (1965) that 6Eu decreases with increasing degree of magma differentiation (i.e., with increasing Si, K and Na). But there are also some exceptions to this rule. For example, among the crust-type granites, those associated with ion-adsorption-type REE deposits, such as the Jiadi granite porphyry and the Yidi biotite granite and some metasomatic granites, such as the Cizhu plagioclase granite are characterized by high levels of Eu and high 6Eu values, thus falling into the area of the transition- type granites. In this case, other aspects such as geological features and backgrounds and signs of later reworking as well as other geochemical data have to be taken into account for a positive
classification.
No~ GEOCHEMISTRY 163
]rig. 14.
bEu 1.2
1.0
0.8
0.6
0.4
0 .2
/o
o °
m2 o ab o
o3 • 4 ,! | |
6 0 80 100 Di
Correlation between o~Eu and DI "in the two series of $mnitm in Jianlpd.
I. Crust-type ~nites; II. trmmi6ou-type ~'anites. 1. Granites rdated to W,S~ Nb, Ta minendimtions;
2. metuonm~ smuite~ 3. $ranites associated with prophyry W m~Mndimfion;
4. ~'anites amociated with porphyry Cu, Au, Mo mlnem~fiom.
RF~ ~ aud M ~ e e , U ~ a
It is a wen ~tab]Lshec] fact ttmt the two series of ~-anites in Jianipd are apparendy different in their metallization specificity. The transition-type gt~mites are associated m~inly with Cu, Mo, Pb, Zn, Au and Ag mineralizations and porphyry W deposits, and the crust-type granites are generally associated with W, Sn, Nb, Ta, REE and U minernli~ations. Clearly, studies on the genetic types of granitoid rocks would contribute more to mineral prospecting. In this respect, the commonly used REE geochemical parameters ~Eu, YREE, ~Ce/~Y and La/Yb have proved to be of great 8i~qli~Gg~no~.
I. Rock bodies with 6Eu > 0.70, Y REE < 200 ppm and La/Yb > 5 are characteristic of metallizations of Cu, Mo, Pb, Zn, Au, Ag and porphyry W deposits. On the other hand, those with 6Eu < 0.70 (especially those with ~Eu < 0.4), ]~REE > 200 ppm, Y~Ce/YY between 0.2 and I.I0 and La/Yb between 0.2 and 5 are associated mainly with metalli~tions of W, Sn, Nb, Ta, REE and U. Among them, some alkali granites associated with Nb and Ta mineralizations may have Y~REE as low as 24---50 ppm.
2. Within a given minerAliTAtion series, there appears to be some correlation between the
1~ GEOCHEMISTRY Yd. 6
magnitude of 6Eu and the association of ore-forming elements. The mineralization series of the transition-type granites can be taken as an example. Rock bodies with 6Eu greater.than, or approximates, unity, such as the Tongchang granodiorite porphyry and the Yinshan quartz porphyry and dacite-porphyrite, usually show close relationship with porphyry Cu (Au), porphyry Cu (Mo), porphyry Cu, Pb, Zn, deposits; those with cSEu less than 0.8, such as the ore-bearing complex at Yangchuling and the monzonitic granite-porphyry at Huanggangshan, are associated mainly with porphyry W deposits; and Cu, W or Mo, W metallizations in porphyry Cu-W, Mo--W deposits may be expected in rock bodies with 6Eu standing between 0.8 and 0.9, such as the porphyritic biotite monzonitic granite at Yongping. This 6Eu-dependent mineralization series can be summarized by the following sequence:
Tongchang (6Eu 1.15) ~ Yinshan (6Eu 1.45--1.00) ~ Yongping (6Eu 0.84) Cu, Mo(Au) Cu, Pb, Zn Cu, W(Mo)
Fengling (6Eu 0.76)~ Yangchuling (6Eu 0.74--0.70)~ Huanggangshan (6Eu 0.64) Cu, W W(Mo) W
Similar regularities are noticed with respect to the crust-type granites. In general, rock bodies with 6Eu > 0.70, such as those at Jiadi (6Eti = 0.88) and Yidi (6Eu = 1.45), show close relations withion-adsorption-type REE deposits. Rock bodies with 6Eu < 0.4, such as those at Xihuashan, Dajishan, Xiatongling and Hukeng are closely related to W metallization. Rock bodies containing tin deposits are usually characterized by even lower 6Eu, for example, the ore-bearing rocks at Zengjialong have 6Eu as low as 0.04, and only a limited increase in 6Eu (up to 0.08--0.14) is noticed in response to Na-alteration. In the case of the transition-type granites, a mineralization sequence of REE ~ W -~ Sn is also indicated with decreasing 6Eu of the ore-bearing rock bodies.
References
[1] Wang Zhonggang, Geochimica, 1(1960), 1--12(in Chinese).
1"2] "Balashov, Yu. A. Tugarinov, A.I., Geology-Geochemistry, 1(1978), 36--37 (translated by Zhao Huilan) (in Chinese).
[3] Zhao Zhenhua, Geology-Geochemistry, 1(1982), 26--33(in Chinese).