沙漠研究 24-1, 237-240 (2014)
Ἃ₍◊✲ 24-1, 237 - 240 (2014)
Journal of Arid Land Studies
Journal of Arid Land Studies－ DT11 Refereed Paper －㸫DT11 Refereed Paper㸫

Research Progresses in Morphological Features of the Area with “Big Ear”
Image in Lop Nor Region and Its Environmental Significance
Xuncheng XIA1) and Yuanjie ZHAO*2)
Abstract: In 1972, a Landsat MSS image clearly showed a “Big ear” shape in Lop Nor region, Xinjiang, China, which is one of theextreme drought regions in the world, and is a typical area to research environmental change of arid zones. For a long time, many
researchers and common people expressed concern about the meaning and origin of the “Big ear” shape. In this paper we summarize
research developments in these areas. The researched results show that the morphological pattern like the “Helix lines” of humanbeing is the yearly and seasonal salt sedimentary structure lines in the process of forming salt crusts. The dark and light change ofcolor tone depends on the burial depth of brine layers, the sand content in the salt crust, and the change in surface texture (roughness).
There are different estimates of the age of formation of the “Big ear” from the 1930s to 1965. In the future, in order to clearly reveal
the process of “Big ear” formation, it is necessary to conduct further accurate measures of the lake basin landform, and regional waterbalance analysis, and to systematically define the function of human activities in the process of Lop Nor drying.
Key Words: Big ear, Dating, Environmental change, Lop Nor

1. Introduction
Lop Nor region is located in the eastern Tarim Basin,
within Bayinguoleng Mongolian Autonomous Prefecture ofXinjiang, China, which is surrounded by Beishan Mountain inthe east, by Tarim River in the west, by Jueluotagh Mountainof the front range of Tianshan Mountains in the north, and by
the north slopes of the Altyn Mountains in the south. It is afamous area in the arid zone of China, the communication
center of the ancient Silk Road, a passageway linking up theeastern cultures with the western cultures, and enjoys a highreputation in Chinese ancient history (Lop Nor Comprehensive
Investigation Team of Xinjiang Branch of Chinese Academy ofScience, 1987). However, due to the changes of the natural
condition and social economy, this region has become a pieceof inaccessible desert and a mysterious area full of natural andcultural curiosities.
In the past hundred years, scholars including Chen Zongqi
and Wang Wenbi during 1927-1935, as well as Nikolai
Mikhaylovich Przhevalsky during 1879-1880, Sevn Hedin
during 1890-1901, Marc Aurel Stein during 1990-1913, andHuntington Ellsworth in 1905, travelled to this area toinvestigate (Xia et al., 2007).
The study of Loulan Civilization is an important activity.
However, the progress in studies of the Lop Nor remained slow
until the 1990s due to its difficult environment and remote* Corresponding Author: ecoenvir@163.com

location, despite growing interest in the area (Dong et al.,2012).
The formation and evolution of Lop Nor “Big ear” shownon the satellite image is an important question and the focus ofsignificant research efforts.
In this paper, we havesummarized the recent progresses in this research area in order
to attract more scholars to pay attention to this, and to provide
new data for the research on high resolution environmental
change in extreme arid zones.

2. Origin of the “Big ear”
In 1972, the satellite image of Landsat MSS of UnitedStates clearly showed the “Big ear” shape in Lop Nor region(Fig. 1) (Xia et al., 2007). In 1980, when the author, Xia
Xuncheng, as a member of the Desert Investigation Delegationof Chinese Academy of Sciences, visited Prof. Farouk El-Baz,a remote sensing specialist in Washington, D. C. USA, they
discussed the “Helix”, “Ear hole” and “Earlobe” of the “Bigear” shape on the Lop Nor image that was hanging in El-Baz’s
home. Since then, the “Big ear” has become an extensive
concern for society.

3. Morphological CharacteristicsAt present, the area with the “Big ear” shape is a dried-up
saline playa. Its area is 5350 km2 just within the region
㸦Received, August 22nd, 2013; Accepted, January 13rd, 2014㸧

No.20, East Road of 2nd South Ring, Yuhua District, Shijiazhuang, Hebei, China, 050024
1) Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, China
2) College of Resources and Environmental Sciences, Hebei Normal University, China

238

Table 1. The chemical composition of different salt crust types.
Salt crust typeFlat salt crust
Crack-like salt
crust
Micro-moundsalt crustContent of different chemical composition (%)
IIIIIIIVVVIVIIVIII

1.76

0.02

0.01

3.91

3.94

1.15

0.6

63.74

1.31

0.03

0.01

3.55

1.02

1.7

0.9

78.24

0.44

0.01

0.01

2.95

2.69

0.74

0.26

77.82

Note: I - CaCO3, II - Na2CO3, III - Ca(HCO3) 2, IV - CaSO4, V - Na2SO4,VI - MgSO4, VII - KCl, VIII - NaCl.

Fig. 1. The completely dry Lop Nor lake basin has formed the “Bigear” or “Helix lines” shape on the satellite image.

surrounded by the isoline of 780m a. s. l. The ground surfaceof the “Big ear” area is covered by various kinds of modern
salt crusts formed in the final Lop Nor drying-up process.
The 51 km range from the Lake Center Island(40º10.753’N, 90º26.691’E) to Lop Nor Town (40º28.148’N,90º52.002’E) can be divided into about 5 salt crust zones.
From 0 km to 12.5 km is the micro-mound salt crust, thethickness of which is 15-25 cm, the diameter of the single
block is 45-80 cm, and the upward height is 5-15 cm. From
12.5 km to 18.5 km is the crack-like salt crust, the thickness ofwhich is 25-45 cm, the diameter of the single block is 30-50cm, the upward height is 10-25 cm. From 18.5 km to 27.5
km is also a type of the crack-like salt crust, the thickness ofwhich is 25-60 cm, the diameter of the single block is 40-70cm, the upward height is 20-120 cm. From 27.5 km to 39.0
km is similar to that from 12.5 km to 18.5 km. From 39.0 km
to 51 km is the flat salt crust, the thickness of which is 20-30cm, the diameter of the single block is 30-70 cm, the upward
height is less than 5 cm (Zhao et al., 2006). The different salt
crust types have evolved from the flat salt crust to thecrack-like salt crust, to the micro-mound salt crust, andeventually to the flat salt crust again along the order from theyounger to the older (Zhao et al., 2005).
The semi-circle-shaped “Helix lines” as seen on thesatellite image are yearly or seasonal salt sedimentary marks
left by Lop Nor sequential drying. The color difference iscaused by the change of the depth of brine layer, sandy content
in salt crust, and the roughness of the ground surface (Zhao etal., 2006).
On the basis of the field measurements, the material
composition analysis, and the satellite image interpretation,
Zhao et al. (2006) revealed that within the “Big ear” area of theEast Lake of Lop Nor, the surface materials are mainlycomprised of rock salt, especially chloride (Table 1), and the
detrital minerals are mainly comprised of quartz. The

formation of “Big ear” shape is controlled by the original
mid-lake island and the lakeshore landform. Cai et al. (2011)
pointed out that the total salt content of the surface soil and themicro-topographical characteristics are the direct causes of theformation of the “Helix lines”. Gao (2012) also thought thatthe total salt content of the sediments is the basic reason for theLop Nor “Big ear”.
By using of the mosaic map of aerial photographs withhigh resolution, combined with the topographic map, elevation
point, digital elevation model, as well as CORONA image on
December 12, 1961, researchers analyzed the Lop Nor waterarea distribution in 1958 (Xia et al., 2007). The results showthat the major water source of Lop Nor was from the northern
Kongque River which flowed into the lake. In the southern
Kalaheshun Lake there are no obvious water flow vestiges.
The west lake area is significantly larger than the water area in
1958 (Xia et al., 2007).
Based on the comprehensive field investigation, combinedwith the information provided from the remote-sensing images,
and the elevation measurement data with high-accuracy by
DGPS on the spot, Li et al. (2008) showed that the relative
depth of Lop Nor “Big ear” in the lake basin is about 5.2 m, theaverage gradient in the southwest is 0.19‰, in the northeast is0.09‰, and the deepest point is located at the “Ear hole”.
The “Helix lines” elevations have lowered gradually from theouter edge of the lake basin to the lake center area, and theelevation value of the same “Helix line” is equivalent. The
density change of the “Helix lines” has an obvious congruent
relationship with the elevations. In other words, the sparser
the “Helix lines” are, the slower the gradient is, which provides
a certain scientific basis to determine that the “Helix lines” arethe salt sedimentary marks formed in the lake water dryingprocess.
Using radar remote sensing techniques which can see
through the wind-sandy sedimentary layers and the extreme
arid salt crust layers, Shao et al. (2011) found the shorelines of
the ancient East Lake buried under the lacustrine sediments of
the West Lake of Lop Nor. This work confirmed there is a
shoreline of the ancient East Lake extending westward
continuously, and explains that the West Lake overlays on theEast Lake. This scientific discovery shows that the ancient239

shoreline of Lop Nor is in a ring shape, not only an ear shape,and locates the ancient shorelines of Lop Nor in the north andwest.

sedimentary environmental changes in the process of Lop Nor
withering and drying, which represent at least 6 events ofclimatic change between the dry and the wet.

4. Chronology

6. Recommendations

As early as 1987, Zhu (1987) mentioned that the various
rings of salt dikes in Lop Nor region are due to Lop Nor
gradually drying. By using the salt formation theory ofmodern salt lakes, combined with formative factors of thesemi-ringed shape on synthesized TM images, Xie et al. (2003,2004a, 2004b) discussed the dating method of the “Helix lines”
by means of remote sensing spectral characteristics and special
climate mark layers. On the basis of topographic map data,landform measurement data, and evaporation rate, Zhao et al.
(2006) calculated that the Lop Nor became completely dry
between 1964 and 1965.
Combined with the water records left by Chen Zongqi in1931 and in 1934 (Chen, 1936), Zhong et al. (2005) and Li etal. (2005) calculated that the “Big ear” may have becomecompletely dry in the late 1930s or early 1940s. Throughinterpretation of remote sensing data, Duan et al. (2013) statedthat during 1958 and 1959 the “Big ear” area was covered bywater, and thereafter, the “Big ear” formed.

Current research of climatic changes in the Lop Nor region
relies primarily on the traditional geological method. The useof the new technique is still inadequate. Accurate extractionof climate and environment proxy information about theclimatic change sequence, the environmental evolution process,the spatial pattern and change of the river system distribution,and the high resolution dating are still in need of further
strengthening. The degree and contribution rate of natural
factors and human factors influencing the Lop Nor drying-up
process cannot yet scientifically be assessed. Thus, futuresystematic and continuous observation and study are necessary
to adequately measure climatic and environmental change.
In order to further clarify the drying process of the “BigEar”, it is necessary to continue accurate measurement of thelake basin landform, to continue analysis of water balance
based on the three-dimensional modeling and the limitedhydrologic data, and to discover more details about theinfluencing factors with regard to the Lop Nor drying process(Duan et al., 2013).

5. Environmental Implication and Significance
Besides the traditional geological methods, the study of
Lop Nor region by remote sensing techniques began in 1980s,
but due to the lack of theoretical basis, many of those works
remain in the stage of optical remote sensing image processing
and visual interpretation (Xia et al., 2007). During the periodof 2006-2010, Shao et al. (2008) for the first time detected theancient lake basin area of Lop Nor region by means of radar
remote sensing techniques, studied the detection mechanism of
new imaging radar detecting underground targets andconcealed characteristic extraction.
Aiming at the typical targets in arid zones, in some respects
such as ground target dielectric property, microwave andelectromagnetic scattering and mechanism of transmission, andparticle polarization theory, Shao et al. (2012) demonstrated
the ability for SAR to detect underground targets, and for the
first time quantitatively illustrated the electrical property of thesediments containing water and salt and its response
characteristics on radar images.
Shao et al. (2012) preliminarily inferred that thedistribution range of the ancient East Lake of Lop Nor may
exceed 10000 km2, much larger than the original measured
area of 5350 km2. The radar image shows 6 alternately dark
and bright stripes, which recorded 6 events of lacustrine facies

Acknowledgement
This work was supported by the National Natural Science
Foundation of China (Grant No. 41071133) and the United
Foundation of NSFC-Xinjiang (Grant No. U1303285).

References
Cai A., Shao Y., Gong H., Wang G., Xie C. (2011): Analysis ofLop Nur “Ear” features in remote sensing image and its
environmental meaning. Spectroscopy and Spectral Analysis,31(16): 1633-1638.
Chen Z. (1936): Lop Nor and Lop Desert. Acta Geographica
Sinica, 3(1): 1-30.
Dong Z., Lv P., Qian G., Xia X., Zhao Y., Mu G. (2012):
Research progress in China’s Lop Nur. Earth-Science
Reviews, 111: 142-153.
Duan H., Alishir K., Zhang Y., Abdumijit A. (2013): Review ofthe studies about the latest dried-up time of the Lop Nur lake
in recent 100 years. Arid Zone Research, 30(3): 541-549.
Gao Z., Shao Y., Gong H., Bian X., Xie C., Cai A., Wan Z.,
Wang G. (2012): Analyzing the genesis of Lop Nur “Ear”
feature based on volume scattering characteristic simulation.
Chinese Journal of Geophysics, 55(3): 906-913.
Li B., Ma L., Jiang P., Duan Z., Sun D., Qiu H., Zhong J., Wu

240

H. (2008): Landform feature and the discussion on dried-up
time of “Big Ear” dried salt lake in Lop Nor region. ChineseScience Bulletin, 53(3): 327-334.
Lop Nor Comprehensive Investigation Team of Xinjiang
Branch of Chinese Academy of Science (1987): The
scientific investigation and research of Lop Nor. Beijing:Science Press.
Shao Y., Gong H., Dong Q. (2008): SAR remote sensing datafor subsurface targets detection and Lop Nur Lake evolution
and extinction study. International Geoscience and RemoteSensing Symposium, IGARSS 2008, July 8-11, 2008,Boston, Massachusetts, USA.
Shao Y., Gong H. (2011): Primary interpretation on shorelinesof vanished Lop Nur Lake using multi-source SAR data.
Journal of Remote Sensing, 15(3): 645-650.
Shao Y., Gong H., Gao Z., Liu L., Zhang T. (2012): SAR data
for subsurface saline lacustrine deposits detection andprimary interpretation on the evolution of the vanished Lop
Nur Lake. Canadian Journal of Remote Sensing, 38(3):267-280.
Xia X., Wang F., Zhao Y. (2007): Lop Nor, China. SciencesPress.
Xie L., Huang S. (2003): Discussion of high resolution remotesensing dating method in the youngest sediments.

Geological Science and Technology Information, 22(3):83-86.
Xie L., Huang S., Li F. (2004a): High resolution remotesensing research of climatic change of Lop Nur saline in past
2000 years. Journal of Chengdu University of Technology(Science &Technology Edition), 31(3): 301-306.
Xie L., Huang S., Li F., Zhang J. (2004b): Global comparisonon palaeoclimatic change in the saline Luobupo during thepast two thousand years. Carsologica Sinica, 23(4):311-316.
Zhao Y., Xia X., Wang F., Cao Q., Lv Z. (2005): Preliminary
study on the geomorphical characteristic and formation
cause of modern salt crust type in Lop Nur region. AridLand Geography, 28(6): 795-799.
Zhao Y., Xia X., Wang F., Cao Q., Gao W., You G. (2006):
Features and causes of formation on ring-shaped salt crust inLop Nur region of Xinjiang, China. Arid Land Geography,
29(6): 779-783.
Zhong J., Qiu H., Dong X., Jiang P., Wu H., Yang P. (2005):Rediscussion on the latest dried-up time of the Lop Nor
Lake. Arid Land Geography, 28(1): 6-9.
Zhu L. (1987): Lop Nor water system evolution. Yindu Journal,
8 (1): 22-26.