587
5 DEGREE INTERVALS
I-DUKOU RRER
i diagram for
.ogioal map.
Xigeda fault are
ey can be clear-
ny parts of the
fold structures
indicative for
ting in a left-
long the fault
l from Yuzao and
ocks of the last
nian stage and
stributed widely
indicates a long
ulting.
hough the NE
on the imagery,
the geological
he zone diorite
tage are present,
rcynian stage
mian period,
eastern side,
h Xigeda forma-
on the north
1 trend of the
e fault and the
northwestern
he river valley
e. A quarternary
and Heishuihe
e of Qionghai
Several earth-
ating present
s an important
s a striking
rges upon the
end near Shimian,
an province,it
The trend of the
tiumian-Lizhong-
ain to Kuangshan-
i-liangzi to
isting of a
ng the fault
Figure 4» Landsat image and fracture structure map interpreted from Landsat imagery in Xichang-Dukou area,
1; Cenozoic; 2: Mesozoic} 3: Palaeozoic; 4: Sinian system; 5s Acid volcanic rocks system of Sinian pe
riod; 6: Proterozoic; 7s Unknown age metamorphic rocks; 8s Intermediate-acid-alkaline rocks of Jinning
stage; 9s Intermediate-acid-alkaline rocks of Hercynian stage; 10: Intermediate-acid-alkaline rocks of
Yanshan stage; 11s Ultrabasic and basic rocks of Jinning stage; 12: Ultrabasic and basic rocks of Her
cynian stage; 13s Permian basalts; 14s Unconformity boundary; 15sStratigraphic boundary; 16: Thrust
fault; 17s Normal fault; 18: Fault zone; 19s Blind fault zone; 20: Conjecture fault zone.
Name of major fault zone:(l) Xiaojinhe fault zone; (2) Jinhe-Qinghe fault zone; (3)
(4) Mopanshan-Luzhijiang fault zone; (5) Anninghe fault zone; (6)Zemuhe fault zone;
fault zone; (8) Xiluohe fault zone; (9) Puxionghe fault zone;(l0) Huapan-Puge fault
Dechang fault zone; (12) Mianning-Yuexi fault zone; (13) Miyi-Huili fault zone.
Lizhong-Dukou fault;
(7) Ningnan-Huili
zone; (11) Xinping-
trend, and thrust faults with thrust movement from
NW to SE. The fault zone forms also an important
geological boundary, controlling the sedimentary
history on both sides of the fault zone since Pala
eozoic. A few hundred meters of Emershan basalts
occur along the fault zone (Yan Xianfu,1981).
According to geophysical data, a negative gravity
anomaly is formed along the fault zone, indicative
for a large crustal thickness.
Most lineaments represent linear fault zones,
except Jinghe-Qinghe fault zone and the Xijianhe
fault. The latter two are arcuate fault zones
which are considered to be formed under com pression-
al stress conditions since a long history.
Figure 1 shows the distance between lineaments
(linear fault and arcuate fault zone) in each
direction to be approximately equal. For example,
the NNE and NNW lineaments consitute a net-like
structure. Their distribution is not limited by
boundary lines of geotectonic units. In general,
the close lineament belts reflect possible fault
zones and /or deep fractures, confirmed by other
geological evidences as gravity anomalies, seismic
data, and sedimentary basin development, indicating
their long geological history. Recent active faults
are represented as clear lineaments on the Landsat
image.
