586 
Figure 2. Frequency and length rose diagram for 
all lineaments ( 5 km) from Landsat imagery. 
A DESCRIPTION OF MAJOR FAULT ZONES 
On the basis of Fig,1 the map of the fracture 
structures (Fig.4) have been compiled of the study 
area. Lineaments interpreted from Landsat are here 
considered to represent major fault zones and frac- 
teurs. 
Anninghe deep fault zone (5): (location of the 
fault zones are indicated on Fig.4 in numbers be 
tween brackets) The Anninghe fault zone is not only 
easily recognizable on the imagery but has been 
determined by geologists in the field. The length 
measured is more than 350 km. It runs from north to 
south through the area and can be divided into two 
parts (Fig.5), The northern part to Dechang extends 
along the Anninghe valley near Xichang with the 
widest part about 15 km. There is series of elong 
ated Quarternary basins developed along the valley, 
and many small rhombus shaped mountans to the north 
of Minning. This is due to tensional charactersties 
along the fault zone. In addition, offset of tribu 
tary streams indicate recent left-lateral displace 
ment along the fault zone. The southern part of the 
Anninghe fault zone appears to be Zig-Zag in shape, 
but is genearlly trending in the north-southerly 
direction. 
According to geological data, the fault zone has 
a long term developed history that strongly contro 
lled the tectonic movements and sedimentary deve 
lopment on both sides of the fault zone (Gong Dai 
lin et.al,1973). A difference in alluvial and di 
luvial fans indicates a veriation in positive and 
negative movement on both sides of the valley in 
the northern part of Xichang. 
Moreover the isopleths of the Douguer gravity are 
extended along the JNS direction from Dhimain to 
Dechang. The gravity gradient in the valley area is 
higher than on both sides. Thirteen times in tne 
recorded period of about 300 years a violent earth 
quake occured along the fault zone (Huang Zuzhi, 
1979)• ^11 of these evidences show that The Anning 
he deep fault zone is a active tectonic zone in 
recent periods. 
Mopanshan-Luzhijiang deep fault zone (4)* The 
Mopanshan-Luzijiang deep fault zone is a NS trend 
ing fault zone. It is situated towards the west of 
the Anninghe fault zone and appoximately parallel 
Figure 3. Frequency and length rose diagram for 
major fracture structures from geological map. 
to it. The Mopanshan fault and the-Xigeda fault are 
the principal fault in the zone. They can be clear 
ly seen on the Landsat image. In many parts of the 
fault zone en echelon NNE directed fold structures 
can be observed. The structures are indicative for 
an ESE-WNW compressive stress resulting in a left- 
lateral transcurrent displacement along the fault 
zone. Many earthquackes are reported from Yuzao and 
Xigeda area. The basic-ultrabasic rocks of the last 
Caledonian stage to the early Hercynian stage and 
the Permian Emershan basalts are distributed widely 
in Hongge and Panzhihua area. This indicates a long 
term activity and large depth of faulting. 
. Ningnan-Huili fault zone (7): Although the NE 
lineaments are easily recognizable on the imagery, 
this fault zone is not important on the geological 
map. On the north-western side of the zone diorite 
and quartz-diorite of the Jinning stage are present, 
as well as diorite-gabbro of the Hercynian stage 
and the Emershan basalts of the Permian period. 
These rocks occur less on the southeastern side. 
Further a big sedimentary basin with Xigeda forma 
tion (Neogene) is developed mainly on the north 
western side. 
Zemuhe fault zone (6): The general trend of thg 
fault is towerds the NNW. The zemuhe fault and the 
Anninghe fault zone converge at the northwestern 
end of the area. The linearity of the river valley 
is clearly seen on the Landsat image. A quarternary 
basin is developed along the Zemuhe and Heishuihe 
valley. It is possible that the lake of Qionghai 
was formed as result of subsidence. Several earth 
quakes occurred in the area,illustrating present 
fault activity. The fault zone forms an important 
stratigraphic boundary. 
Jinhe-Qinghe fault zone (2): It is a striking 
arcute type of fault zone. It converges upon the 
Anninghe fault zone at the northern end near Shimian, 
At the southwestern end,in the Yunnan province,it 
is cut off by the Yuanjiang fault. The trend of the 
fault zone varies from NNE in the Shumian-Lizhong- 
Zhoujapain area to N-S form Zhoujapain to Kuangshan- 
liangzi, and NE trend from Kuangsh'an-liangzi to 
Qinghe (Fig,6). 
There are related structures consisting of a 
series of closed folds occuring along the fault 
Figure 4» 
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