LIANG Enyun, ZENG Zhifang, LIU Gengyin, ZENG Guangqian, ZOU Guangjun, XU Ruochao, ZHAO Wei
2025, 45(2): 135-146.
The
Dayishan
area
of
Hunan
province
is
located
in
the
transition
zone
between
Yangtze
and
Cathaysian
Block,
also
is
in
the
superposition
of
Qinhang
metallogenic
belt
and
Nanling
metallogenic
belt.
The
Dayishan
pluton
is
characterized
by
multiple
stages
of
intrusion
and
strong
alteration.
The
lithium-bearing
granites
in
Dachongli
mining
area
can
be
divided
into
three
stages
of
intrusions:
medium-grained
porphyritic
biotite
monzogranite ( ηγJ
a
3 ),
fine-grained
porphyritic
two-mica
monzogranite ( ηγJ
b
3 )
and
fine-grained
two-mica
monzogranite( ηγJ
c
3 ).
In
order
to
reveal
the
mechanism
of
lithium
mineralization,
this
paper
takes
petrogeochemistry
as
the
starting
point
to
explore
the
characteristics
of
granite
evolution.
It
is
found
that
the
average
content
of
SiO2
in
granite
of
Dachongli
mining
area
is
75. 13%,Na2O+K2O
is
5. 99%,10
000
×
Ga / Al
is
3. 88,
and
T
FeO/ MgO
is
21. 70.
It
has
a
flat
“seagull
shaped”
REE
patterns,
enriched
in
Rb,
Th,
U
and
Y,
with
loss
of
Ba
and
Sr.
It
belongs
to
A-type
granite.
In
Yb-Ta
and
Y-Nb
diagrams,most
of
the
granites
in
Dachongli
mining
area
drop
point
into
the
range
of
intraplate
granite. Combined
with
previous
studies,
it
is
believed
that
they
are
formed
in
the
early
Yanshan
intracontinental
extensional
environment.
From
early
to
late
stages,
each
stage
of
granite
follows
the
law
of
magmatic
evolution,
with
∑REE,
LREE,
HREE,
LREE / HREE,
Th,
Zr
and
Hf
values
decreasing,
while
Li,
W,
Sn,
Bi,
Rb,
U
and
Nb
are
increasing.
The
average
content
of
Li
varies
from
538×10
-6→734×10
-6→2
218×10
-6
,
with
a
coefficient
of
21. 2%→29. 8%→74. 3%,
which
reflects
that
Li
is
more
enriched
and
more
conducive
to
mineralization
in
the
fine-grained
two-mica
monzonitic
granite
of
the
late
stage.
