DIAO Qian, ZHEN Yun-qing, NIU Shu-yin, SUN Ai-qun, SONG Tao, SUN Lu
Journal of Guilin University of Technology.
2022, 42(1):
29-45.
Based
on
preliminary
study
of
the
“ southern
ancient
land
block”
in
North
China( ZhongtiaoshanWangwushan-Xiongershan
and
East
Qinling
Mountains),
the
stretching,
extension
and
uplift
and
compression
of
the
crust
in
this
area
occur
throughout
the
tectonic
evolution
of
the
earth.
This
kind
of
open-close
tectonic
cycle
shows
the
phenomenon
of
“big
opening
and
big
closing”
and
“small
closing
and
small
opening”.
The
migration
of
opening-closing
tectonics
cycle
according
to
“three
steps”
is
southward,
and
the
geological
age
of
multistage
rifting
and
mineralization
tends
to
change
gradually
from
north
to
south.
During
the
period
of
2. 5
Ga
to
1. 73
Ga,
the
area
experienced
the
sedimentary
formation
of
Jiangxian
Group
of
eugeosyncline
dominated
by
extension
in
the
near
EW
direction,
and
evolved
into
the
sedimentary
formation
of
Zhongtiao
Group
of
miogeosyncline
dominated
by
subsidence
in
the
NE
direction.
It
is
actually
a
record
of
two
rift-type
constructions,
controlled
by
the
Jiangxian
Movement
and
the
Zhongtiao
Movement.
In
the
meantime,
the
Danshan
Group
of
molasse
formation
might
have
deposited
successively
due
to
collision
orogeny. In
the
vast
area
of
Songshan,
Xiongershan
and
Xiaoshan
in
the
southeast,
the
bimodal
Xionger
Group
sedimentary
formation
dominated
by
intermediate-basic
volcanic
rocks
erupted
(overflowed).
There
are
A-type
granite
intrusions
in
some
areas,
and
it
is
also
a
passive
continental
rifting
environment,
undoubtedly
inseparable
from
the
Proterozoic
mantle
plume
activity.
Accordingly,
it
can
be
called
the
“previous
life”
of
the
Zhongtiao-Xionger
multi-stage
rift.
In
the
eastern
Qinling
area( including
the
Xionger
Group),
the
Mesozoic
Yanshan
Movement
is
dominant.
Confirmed
from
seismic
tomographic
data,
the
deep
low-velocity
and
high-conductivity
layers
are
columnar
bodies,
as
the
“present
life”
of
the
Zhongtiao-Xionger
multi-stage
rift,
obviously
a
typical
example
of
composite
mantle
plume
structure.
In
the
Zhongtiaoshan-Wangwushan
area,
the
mineralization
is
dominated
by
Proterozoic
copper
deposits
(containing
Au,
Mo,
and
Co).
In
the
Xiongershan-East
Qinling
area,
there
are
also
a
small
amount
of
Mesoproterozoic
and
Paleozoic
gold
deposits(containing
Mo
and
Co),
but
mostly
gold
and
molybdenum
(containing
W,
Pb-Zn,
Be)
deposits
in
the
Indosinian
and
Yanshanian
periods,
important
metal
ore
clusters
in
China.
There
are
many
types
of
ore
deposits
in
the
area,
basically
related
to
the
emplacement
of
transmagmatic
oreforming
hydrothermal
fluids. According
to
statistics,
large-
and
super-large
deposits
are
controlled
by
crustal
extensional
fracture(opening)
environment
or
open-close
tectonic
transformation
area.
In
view
of
the
specific
exploration
situation
of
Zhongtiao-Xionger
multi-stage
rifting,
eight
suggestions
for
key
prospecting
are
put
forward
for
reference.
