02yd0366.pdf

8/10/2019 02yd0366.pdf

1/15

Vol. 45 No. 4 SCIENCE IN CHINA (SeriesD) April 2002

The covered karst, weathering crust and karst (double-level)

planation surface

CUI Zhijiu ()1, LI Dewen ()2, FENG Jinliang ()1,3,

LIU Gengnian ()1 & LI Hongjiang ()4

1. Department of Geography, Peking University, Beijing 100871, China;

2. Department of Geography, Nanjing University, Nanjing 210093, China;

3. Institute of Geography, Hebei Academy of Sciences, Shijiazhuang 050011, China;

4. Department of Geophysics, University of Chicago, Chicago 60637, USA

Correspondence should be addressed to Cui Zhijiu (email: [email protected])

Received November 15, 2001

Abstract The thick-bedded and continuous karst crust only formed in the old stage of geomorphic

development. The corresponding landscape is the karst planation surface. The karst planation

surface consists of the loose weathering crust and the base weathering front below the crust. Its

profile structure is similar to double surface of leveling model built by Budel. In the limestone

area, the base weathering front is the covered karst. From the Tibet Plateau to Yun-Gui (Yunnan-

Guizhou) plateau and Xiang-Gui (Hunan-Guangxi) hills, the covered karst is concomitant with the

red weathering crust; all of them are the component of the double-level surfaces of karst planation.

But, they belong to the different disintegration stages of planation surface. The different subtypes

of the covered karst and the red weathering crust indicate the existence of karst planation surface.Thus, they can be made as a reference system when the rising degree and the rising rate of the

Tibet Plateau are discussed.

Keywords: covered karst, weathering crust, karst planation surface, Tibet Plateau.

The limestone pillars often observed in the Tibet Plateau are always the argument focus of

the paleo-karst research[1]

. Since the red crust co-existing with the limestone pillars had been dis-

covered, most limestone pillars are believed to be a result of the covered karst. They formed below

the loose crust and then are denuded to form stone-forest, stone-wall, etc. on the ground due to the

tectonic uplift. Now, scientists believe that it is important to resolve the rising problem of the Tibet

Plateau[2]

. Meanwhile, the recrystallization calcite obtained from the covered karst bilge could be

used to dating (the fission-track ages are about 197 Ma B.P), which provides a new way to re-

solve the rising degree and the rising speed of the Tibet Plateau[3,4]

. If we want to estimate the ris-

ing degree of the Tibet Plateau according to the covered karst, two basic problems have to be re-

solved. The first is how to confirm the existence of planation surface based on the covered karst

and the red karst weathering crust; the second is to establish the original height of the planation

surface. On the basis of field investigation about the covered karst in the Tibet Plateau, Yun-Gui

(Yunnan-Guizhou) plateau and Xiang-Gui (Hunan-Guangxi) hills (fig. 1), the planation process of

the karst landform has been discussed again from the essence of karst process in the paper.

8/10/2019 02yd0366.pdf

2/15

Fig. 1. Study region, samples spot and spatial distribution of the subtypes of the covered karst. The section characteristics tion/elevation (m)/thickness(m)/number of samples). Ad, Aduobeishan/5125/0.76/8; Ce, Cuoe/buried crust/2/10; Drq, DingridongZD2, /Napahaibei/3450/1.5/4; BHC2, Wuzhubi/3000/4/5; BHC1, Baihanchang/2500/2.5/3; HQ2, Shibaoshan/2250/2/4; LH, XiHQ1, Shibaoshan/2500/4/5; DLD, Dalongdong/2100/11/12; TBK, Tuobuka/2000/1/11; HZ, Dahai/2800/6/7; NJ, Dasongpinghan/2000/2.5/4; LNSL, Dashilin/1900/2.5/3; NGSL, Naigushilin/1900/6/9; JP, Jiepu/2000/3.5/4; MHS, Meihuashan/2500/6/7; way/1450/5/7; MW, Mawei/900/3.5/5; MS, Maoshi/1400/3/4; YZ, Qingquanjing/150/8/8; GL2, Yaoshan/800/8/7; GL1, Nanchai/2500/5/6. 1, Red weathering crust (on the limestone); 2, red weathering crust (on the non-limestone); 3, capital of province; karren; 7, karren denuded by human; 8, subtype boundary of covered karst; , un-naked subtype of the covered karst; , hasubtype of the covered karst.

8/10/2019 02yd0366.pdf

3/15

8/10/2019 02yd0366.pdf

4/15

No. 4 COVERED KARST, WEATHERING CRUST & PLANATION SURFACE 369

stream of the Zhujiang, Changjiang (Yangtze R.), Honghe and other rivers. The covered karst ex-

ists as the half-naked subtype and preserves very well. Its upper part crops out to form stone-forest.

The famous Lunan Stone-forest is located in the headstream of Bajiang River, one tributary of

Nanpan River. This region is a shallow depression in the plateau. Some papers discussed the

stone-forest genesis by sub-soil and the relationship between the planation surface and sub-soil[6]

.

The large stone-forest is tall and straight with relative height from several meters to 30 m. In addi-

tion, its upper part crops out with sharp-point and the lower part immerges into the weathering

crust (Plate -2). Except for a few isolated pillars, the main part of the Naigu Stone-forest likes a

castle of limestone or platform of limestone because it is close to watershed and not completely

incised. The netlike grooves developing along joints are downward several meters. The dissolving

grooves, the niches and window-shaped cavities are often observed. The solution niches are lo-

cated in the bedrock surface (between rock and soil) or a little upperward, with far transverseextension. The fossil in the protolith crops out on the rock surface since it is difficult to dissolve.

The top and the upper parts of half-naked karst of the Stone-forest Scenic Spot of Lunan are

intensely deformed to become sharp-pointed by late rainwash. But the downward part has the

obvious original characteristics formed by the sub-soil. In contrast with stone-forest of the Middle

Yunnan, the half-naked karst of the Guizhou Plateau has a few characteristics formed in the open

air.

The most karst of Xiangnan (southern Hunan) and Guibei (northern Guangxi) areas belongs

to un-naked subtype, some peak-forests develop in tower-shape and columnar shape on the openkarst plain. The stone-forest and the karren with dissolving features formed by sub-soil are ob-

served in the artificial cross-sections (Plate -3). For example, in open pit of mining soil near

Qifeng Town of Guilin City, columnar stone-forest of more than 3m in height distributes occa-

sionally with round shape and smooth surface features formed by sub-soil (Plate -4).

From the Tibet Plateau to south Guizhou, northwest Yunnan, south Sichuan (Wansheng

County, Xingwen County) and other places, the covered karst of various subtypes can be found

easily. Their common characteristics are as follows: () As to the shape, they all have the charac-

teristics formed by sub-soil. Exquisitely carved and smooth dissolving surface of rock is often

observed at Angren, Anduo, Biru, Zhongdian, Middle Yunnan, Middle Guizhou and other places,

especially in the lower part near the red crust. The solution niches often observed in the Tibet Pla-

teau can be also observed in Yunnan Province and Guizhou Province, such as the Stone-forest

Scenic Spot of Lunan and the Hongfenghu Scenic Spot. In Xiang-Gui (Hunan and Guangxi) zone,

the small window-shaped cavities, the niches and the caves are also observed in stone-forest that

is denuded by human. In addition, the nearer it goes downward to the bottom of the stone-forest,

the more clear the features formed by sub-soil show. Because parts of stone-forest and stone-wall

have various transverse features at the different heights, making clear that the denudation proc-

esses of the stone-forest and the stone-wall were gradual, intermittent and multi-stage. () As to

8/10/2019 02yd0366.pdf

5/15

8/10/2019 02yd0366.pdf

6/15


(continued)

Location Longitude

/E

Altitude/m

Depth/m

Sampling depth/cm

Ratio ofSi/Al

0.001 mm

(%)

CaCO3(%)

pH CEC/

cmolkg1

Zunyi, NorthGuizhou

107 1400 2 40 2.51 45.2 1.74 6.96 14.88

120 2.27 63.2 1.25 6.96 21.27200 2.28 82.3 1.32 7.04 16.86

Guiyang,Middle Guizhou

106.5 1250 7.5 50 3.84 37.6 2.97 7.72 47.20

150 3.98 37.7 1.99 7.87 40.69

250 3.32 63.0 3.57 7.55 49.29

350 3.10 60.6 2.89 7.59 41.73

450 3.22 57.8 3.69 7.77 48.73

550 3.28 58.4 3.3 7.69 55.24

650 3.23 54.6 3.54 7.72 42.89

750 3.30 55.2 3.64 7.59 44.1

Guilin,

Guangxi 111 150 6 40 2.25 65.6 0.54 7.33 34.13

150 2.27 64.2 0.55 7.01 37.81

250 2.33 61.5 0.81 7.31 38.32

350 2.34 62.6 1.02 7.68 41.48

450 2.35 67.6 0.87 5.57 46.21

550 2.36 58 1.70 7.85 45.16

a) The following three samples were gathered successively from 67 cm downward.

In the Tibet Plateau, there is recrystallization of the Miocene calcite in the inner wall of the

bilge of stone-wall or stone-forest (gathered 30 samples and got 20 dating data[3]

). Thus, these

karst shapes formed during the Miocene epoch. If they were not covered by crust at early stage

and then were denuded, it would be very difficult to keep these karst forms up to now.

2 The characteristics of the karst weathering crust

In the hinterland of the Tibet Plateau, such as Dingri and Anduo counties, the red weathering

crust can be observed in the weathering fissures or part depression. Its thickness usually is less

than 1 m and rock-fragment comprises one part of it. Along east direction to Zhongdian County,

the thickness of weathering crust generally is not more than 1.5 m. In the Yun-Gui (Yun-

nan-Guizhou) Plateau and Xiang-Gui (Hunan-Guangxi) hills, the transverse distribution of red

crust is continuous. The thickness of red crust is generally about 35 m, with a few sections in

78 m thickness. In some areas, such as Dalongdong of Zhaotong City, the line from Dali to Li-

jiang and Shigu, the thickness is more than 10 m. The characteristics of some sections are as fol-

lows:

Northern Tibet: In the summit of the Anduobei Mountain, the thickness of residual weather-

ing crust is more than 70 cm, where 08 cm is roots layer, 820 cm are red fossil soil with peb-

ble-bearing, 2042 cm are yellow sand layer with roots and calcite spot, 4247 cm are red sand

clay, 4767 cm are yellow layer of coarse silt, below which is red clay layer with limestone frag-ment.

Northwest Yunnan: In the northwest of Zhongdian Basin, there is a section close to the

8/10/2019 02yd0366.pdf

7/15

372 SCIENCE IN CHINA (Series D) Vol. 45

Yirengang Pass (4000 m a.s.l.), where 030 cm is black and deep gray top soil with roots, about

30180 cm are brown-red clay with a clear interface to overburden, and below is deep gray lime-

stone with a clear interface to the upper soil. On the surface of limestone, bag-shaped cavities and

notches karst can be observed and the intensity of surface relief is about 0.5 m.Middle Yunnan: Near the Stone-forest Station of the Nanning-Kunming railway, there is a

section of red weathering crust (1900 m a.s.l.), where 020 cm is top soil with humus and resid-

ual roots, below is red clay layer with a clear interface to upper layer. The maximum thickness is

about 7 m (in the fissures). Under the red clay is gray limestone. The relief intensity of interface is

12 m and various kasrt shapes formed by sub-soil can be observed in the section.

Middle Guizhou: On the plateau surface of Tianhetan of Guiyang (1250 m a.s.l.), there is a

section of crust in one fissure, where 020 cm is top soil with brown colour and roots, and down-

ward is red-clay with 8 m in thickness, and below is gray limestone.

South Hunan: On the middle way from Daoxian County to Ningyuan County, there is a sec-

tion formed by mining soil (200 m a.s.l.), where 010 cm is top soil with black-brown color. The

middle part is red clay with 24 m in thickness. In the fissures of limestone, the thickness is more

than 5 m. The lower part of the section is limestone with small stone-forest and other shapes. The

interface between rock and upper red soil is irregular.

The authors gathered 178 samples (152 soil samples and 26 bed-rock samples) from sections.

About soil sample, the size analysis, chemical analysis (only clay particle) of soluble salt and

other experiments had been made (partial results in table 1). According to experiment results, we

found that the indexes affected easily by modern environment have obvious characteristics of re-

gional difference, such as pH, CaCo3 content. Other physical and chemical indexes, such as clay

particle content, the ratio of Si/Al, have no regional difference concordant with modern environ-

ment, but present identical characteristics in the whole research areas. Although they are far away

from each other and their elevation difference is large (about 5000 m); their characteristics are

similar to red calcareous soil. On Anduobei Mountain (5100 m a.s.l.), clay content of red calcare-

ous soil is still up to 58% in the down part of residual weathering crust. The size analysis results

of red karst weathering crust indicate that their clay content is higher than that of calcareous soil

(30%50%), so the water, the thermal conditions and the lasting time are enough for process of

soil formation. From the result of XRD clay mineral analysis and capacity of cation exchange

(CEC), we know that most clay minerals of soil sample are 21 type, especially the samples of

the Tibet Plateau and the Yun-Gui (Yunnan-Guizhou) Plateau. Therefore, we believe that they

have the common development history.

Based on the pH value of weathering crust, except for a few samples gathered from the mid-

dle part of profile with neutrality or acidity, most samples of profile are alkaline (7.58.5) or highalkaline (>8.5), especially in the lower part of profiles. Trudgill ever pointed out that underlying

8/10/2019 02yd0366.pdf

8/15


limestone could not be effectively dissolved by upper-soil if the pH value is within 79 and

CaCO3content is higher than 10%[7]

. According to CaCO3illuviation of lower part of profile, the

solution below the soil is very weak now. On the Anduobei Mountain, the pH value of the bottom

sample is up to 9.03 and the CaCO3 content is 23.69%, thus this kind of crust only preserves theunderlying limestone. These facts indicate that the red weathering crust and the concomitant cov-

ering karst cannot be produced under the present environment.

Based on the above, the covered karst of Qingzang Plateau (Tibet Plateau) and the eastern

areas have typical characteristics of sub-soil corrosion and the red weathering crust has the similar

characteristics.

3 The karst (double-level) planation surface

3.1 The weathering crust and the planation surface in the karst area

As for the weathering crust, there are two obvious differences between the karst landform

and the normal landform. First, in the karst area, the corrosion is the main weathering process, so

the weathering process of limestone is the denuding and transporting processes at the same time.

Due to residual material is less than protolith, the formation of karst crust must be concomitant

with large-scale reduction of rock volume[8,9]

. Thus, in the end, it will lead to leveling off and de-

grading of landform. Second, in some places with deeper groundwater table and large relief, the

dissolution made joints further open and soil fall into caves system near surface. These phenom-

ena are called soil loss[5]

. So, on the karst mountain, the soil is mainly partly preserved

black-calcareous soil. Even in the dense primitive forest, thick and continuous crust cannot form,

such as the karst and forest protection area of Libo, which is located in the southeast edge of Yun-

nan-Guizhou Plateau (this protection area belongs to the intermediate district slope between pla-

teau and the Guangxi Basin, and the vertical karst processes are very active). The ground surface

almost consists of naked rock. A few fissures have humic soil and black-calcareous soil. So the

thick crust of karst only formed under the conditions of small relief and non-active karst processes

on vertical direction. Based on the theory of geomorphic development, such conditions can be

observed on the karst planation surface close to base level of erosion. For this reason, it is believed

that the thick crust not only contains a large amount of environmental information, but also indi-

cates directly the old stage of geomorphic development. In this stage, the planation surface had

formed and landform surface approached to the base level of erosion. When Yakuchu studied the

karst landform of the tropics, he referred to that continuous and loose crust only formed during the

old stage of geomorphic development, but he did not link this with the planation surface[10]

.

According to the double surfaces of leveling theory built by Budel in granite area with hu-

mid and warm climate, the weathering crust consists of two active surfaces[11]

. One is the upper

wash surface of loose layer under the open air, the other is the base weathering front. In the study

area, the karst red weathering crust consists of two surfaces as well, one is the upper wash surface,

the other is the lower covered karst. Therefore, the concept of double surface can be used in the

8/10/2019 02yd0366.pdf

9/15


karst area for the following reasons: () Expressing the difference of formation mechanism about

the crust and the different significance about geomorphic development between the karst landform

and the normal landform. () Some results of double surface can be used as well. The planation

surface with thick crust forming during the old stage of geomorphic cycle is named as the doubleleveling surfaces of karst planation.

3.2 The comparison between double leveling surfaces of karst planation and the double sur-

face model of Budel

First, the developing patterns of the double leveling surfaces of karst planation surface are

different from those of the double surfaces model of Budel. The normal landform process de-

velops on the ground surface or the inside rock close to ground surface. The crust renews con-

tinuously in the process of landform developing downward. So, in the different developing stages,

non-karst crust may exist on the planation surface, and on some summits, and its significance of

the geomorphic development is uncertain[12,13]

. In the karst area, the karst process can develop

within the whole rock layer upon the base level of erosion. Under the conditions of deeper base

level of erosion and deeper groundwater table, vertical karst process broadens continuously the

fissure system under ground and most leaching residues move downward along the fissures. It led

to that the accumulation of weathering material on the surface is very difficult. In the tropical and

the sub-tropical forests where the karst process is most active, so long as the landform has some

relief, it is difficult to form the thick and continuous soil. Among the existent soil, the most belong

to AF-D type, or A-D type section[14]. In the primitive forest, with the active vertical karst process,

Trudgill found that rock surface was covered with thin lichen and most soil is acidic and organic

soil with 1020 cm thickness[7]

. So before the landform surface close to base level of erosion, the

thick and continuous crust cannot form generally. The double leveling surfaces of karst planation

indicate that the thick crust of karst areas only forms during the old stage of geomorphic evolution.

On the basis of characteristics of karst process and field observation data, the concept of double

leveling surfaces of karst planation surface is going to connect the thick crust with the planation

surface. So it has a special geomorphic significance that is different from the normal weathering

crust.

The double leveling surfaces of karst planation benefit further understanding the covered

karst and the genesis of subtype forms of the covered karst. The double leveling surfaces of karst

planation consist of the continuous and thick crust and the covered karst. For this reason, the crust

and covered karst not only can be taken as the evidence to prove the existence of the double lev-

eling surfaces of karst planation, but also have the same geomorphic significance with planation

surface1)

. Though the double surface model of Budel was used to explain the formation process of

1) If the wash surface is made as the elevation of planation surface, the evolution of covered karst is little less than original

karst planation surfaces (the height difference is equal to the thickness of crust). In view of planation surface with great spatial

scale, the idea that regards covered karst and planation surface as the same elevation may be accepted.

8/10/2019 02yd0366.pdf

10/15


tor and other landform, it is unreasonable to deny the slope retreat theory of King for non-karst

areas[15,16]

. Similarly, the view regarding the etchplain of non-karst areas as one type of planation

surface has been challenged in some degree[17]

.

4 Evolution of covered karst in correspondence with uplift of Tibet Plateau

The covered karst and the red weathering crust are evidences of the existence of the double

leveling surfaces of karst planation, thus indicating the surface of that time corresponding with the

old stage of karst landform and approaching the base level of erosion. Meanwhile, the red cal-

careous soil consisting of the red weathering crust also indicates tropic and subtropic environ-

ments which have intensive eluviation and good draining conditions[18]

. The analytic results of red

weathering crust of research areas indicate that they have the similar granulometric composition

and characteristics (table 1). Therefore, the covered karst and the red weathering crust formed in

the environment having enough water and thermal quantity and gentle relief on the planation sur-

face, and they all belong to a unified double leveling surface of karst planation (figs. 2 and 3).

This has an important significance for the development history of karst landform of the South

China and the estimation of plateau rising degree and speed according to planation surface.

Fig. 3. The sketch of topography evolution of the Tibet Plateau and neighbouring region during the late Cenozoic.1, The western boundary of the half-naked subtype karst (3500 m or so); 2, the eastern boundary of the half-naked

subtype karst (1500 m or so); the upper is the section position of the planation surface; AAis the Tibet-Deccan

section; BBis the section of the Tibet Plateau and neighbouring region.

According to double surface of leveling theory built by Budel, when ground rising is quick,

the speed of erosion is higher than that of weathering, and depth of loose layer decreases until

outcrop of microtopography of base weathering front is exposed. This is the process of etchplain

8/10/2019 02yd0366.pdf

11/15


formation[2]

. The microtopography outcropped on the etchplain is called inselberg or tor in non-

soluble rock areas[15]

. The covered karst outcrops as the forms of stone-forest, karren or stone-wall

in karst areas. Thus in the western and middle parts of research areas, the stone-forest and the kar-

ren often observed on the ground are the special landform corresponding to inselberg or tor. Based

on the double leveling surfaces of karst planation theory, these characteristics can help to under-

stand geomorphic implication of the covered karst and the genesis of sub-class karst forms. So, it

is not in the same class with peneplain. If this idea is correct, our contribution is that the karst

etchpalin is the production of disintegrating process of the unified planation surface and has vari-

ous forms based on different etching degrees, such as entirely naked subtype and half-naked sub-

type.

The covered karst of the Qingzang Plateau (Tibet Plateau), Yun-Gui (Yunnan and Guizhou)

Plateau and Xiang-Gui (Huann and Guangxi) hills has the same genesis, but their existent forms

are very different along eastern-western direction. The unified karst planation surface turns into

three subtypes because they outcropped as various degrees due to the different rising degrees of

original planation surface. () Entirely naked subtype corresponds with intensive rising of Qing-

zang Plateau (Tibet Plateau) and complete denudation; () The half-naked subtype corresponds

with moderate rising of Yun-Gui Plateau (Yunnan and Guizhou); () The un-naked karst corre-

sponds with little rising. Thus different subtypes also indicate different rising degrees. As to the

middle and little scales, except for the residual features of dissolution formed by sub-soil, all the

secondary features of the rock surface are different. These phenomena are due to several reasons.The first reason is the etching degree. In shallow etching areas, there exist mainly distribution of

the stone tooth, but the large landforms such as stone-forest and stone-wall are not often observed.

The second reason is the difference of intensity, types and the lasted time of outside forces action

after cropping out. The covered karst of Qingzang Plateau (Tibet Plateau) denuded entirely,

cropped out for a long time and the frost weathering is very intensive, thus slender forms are dif-

ficult to preserve and the large stone-wall can widely distribute. Besides, it is affected by

lithologic characters and attitude as well.

5 The geomorphic significance of karst planation surface

As for the role of planation surface in research of plateau rising, the difference between the

karst planation surface and the base level of erosion has important significance to estimate plateau

rising degree and speed. With the landform evolving toward planation surface, the gradient of

ground surface decreases gradually (the gradient of planation surface is no more than 1

2[2,3,19]

). Contrasting with normal landform area, the leveling rate of landform in karst area may

be more greater. In the normal landform area with low gradient, the transport capacity of running

water decreases obviously due to intensity of exogenous process weakening, and the material canbe transported only if it undergoes continual weathering and becomes small grain. The upper ma-

8/10/2019 02yd0366.pdf

12/15


terial accumulated to counteract the weathering force developing downward. So, the planation

process of landform is sensitive to the change of gradient of ground surface. Based on Millimans

researches[20]

, the amount of suspended matter inflowing into sea from the rivers originating from

the high land (maximum elevation more than 3000 m in the drainage basin) is 23 orders of

magnitude more than that from the low land (100500 m a.s.l.). The geomorphic evolution of

karst areas is relatively simple. The capacity of chemical transportation is not affected by land-

form relief (the sedimentation ratio of dissolution material inflowing to sea has no obvious rela-

tionship with ground relief)[20]

. The residual fine-grained material is easily transported by water

after the dissolution. So, the leveling rate of karst does not decrease rapidly with the decrease of

landform relief. The normal landform is contrary.

On the other hand, the vegetation impact on the geomorphic process is different in the dif-

ferent areas, such as the karst areas and the non-karst areas. In the karst area, the organic acid isproduced by the biological and chemical processes and the biological chelation is favourable to

the karst process. In the non-karst areas, the vegetation prevents effectually water and soil erosion.

Then it made the development of the base weathering front more difficult, especially emergence

of herbage after the late Cenozoic[21]

. In the tropic and sub-tropic areas with the similar climate

and landform relief, the production rate of dissolved material inflowing to sea and deposits has a

linear relation with rainfall, but the suspended load has not[20]

. Thus, according to the geomorphic

features, the hydrologic characteristics, the vegetation and the climatic conditions, the leveling

rate of karst planation is faster than that of normal landform and so its altitude of planation surfaceis lower. This idea is also supported by fieldwork. For example, the karst areas of Yongzhou and

Daoxian County of South Hunan Province are close to the old stage of geomorphic evolution.

They are far away from the estuary, but the karst plain is about 200 m in altitude. The maximum

altitude of surrounding granite mountains is up to 10002000 m.

Based on the forming processes of the planation surface, the united pediments formed by

pediplanation process cannot be regarded as the evidence of plateau rising because they can be

formed simultaneously at different altitudes. The peneplain of non-karst area develops very slowly,

which needs tectonic stability of millions of years. Therefore, it is not very useful to study geo-

morphic evolution of the Qingzang Plateau (Tibet Plaeau) of the late Cenozoic epoch. The devel-

oping rate of the karst planation surface is relatively large and the altitude of planation is small.

Meanwhile, its development and reservation are sensitive to environmental changes. Thus karst

planation surface is indispensable in research of plateau rising.

6 Summary

(1) In the research of limestone planation surface in the Southwest China, it is believed that

the etchplain existed only in the disintegration process of the planation surface. The etchplain,peneplain and the pediment are not the same class of the planation surface.

8/10/2019 02yd0366.pdf

13/15


(2) The tectonic disintegration of the planation surface is shown as the landform surface with

different elevations, and the landform surface with the different etching degrees. Thus, the etch-

plain could have various subtypes, such as the half-naked subtype and entirely naked type. In ad-

dition, due to the etchplain forming in the process of rising-etching, it did not extend far away. In

fact, it always exists as the blocky surfaces separating each other, such as the Anduobei Mountain,

the Lunan Stone-forest and other places.

(3) During the old stage, the relief of limestone planation surface is becoming gentle. The

process of mechanical transportation was superseded by chemical transportation. As the decrease

rate of ground height of limestone area is much more than the non-limestones, the height of lime-

stone ground is lower than other rocks in the end. Generally, the total gradient of ground surface

is small during this period, but the specific inselberg of non-limestone could have more differ-

ences in height.

(4) The double leveling surface of karst planation exists not only in the late Cenozoic, but

also in other periods. On fossil planation surface of North China, it formed during the Mid-

dle-Ordovician to Middle-Carboniferous period. On the fossil planation surface, the bauxite

formed from limestone weathering indicates that the double leveling surfaces of karst planation

existed in the geologic history1)

.

Acknowledgements This Project was supported by Research Project of the Tibet Plateau from Chinese Academy of

Sciences (Grant Nos. KZ951-A1-204; KZ95T-06) and the Key Foundation of National Basic Researches of China (Grant No.

G1998040800).

References

1. Zhu Xuewen, The properties of karst and discussion of residual peak forest in Tibet Plateau, Chinese Karst (in Chinese),

1994, 13(3): 220228.

2. Cui Zhijiu, Li Dewen, Wu Yongqiu et al., Comment on planation surface, Chinese Science Bulletin, 1999, 44(22): 2017

2022.

3. Cui Zhijiu, Gao Quanzhou, Liu Gongnian, Paleo-karst, planation surface and plateau rising, Science in China, Ser. D,

1996, 39(4): 391400.

4. Cui Zhijiu, Gao Quanzhou, Liu Gengnian, Initial elevation of paleokarst and planation surface on Tibet Plateau, Chinese

Science Bulletin, 1997, 42(11): 934938.

5. Li Dewen, Cui Zhijiu, Liu Gengnian, The existence of Tibet paleo-karst and comparing with that of the east area to Tibet,

Chinese Karst (in Chinese), 1999, 18(4): 309318.

6. Lin Junshu, The formation process and environmental changes of Lunan Stone-forest, Chinese Karst (in Chinese), 1997,

16(4): 346350.

7. Trudgill, S., Limestone geomorphology, New York: Longman Inc., 1985.

8. Yuan Daoxian, Chinese Karst (in Chinese), Beijing: Geological Publishing House, 1994.

9. Wei Qipan, Chen Hongming, Wu Zhidong, The geochemical properties of calcareous soil of Nonggang, Guangxi Province,

Journal of Soil Science (in Chinese), 1983, 20(1): 3041.

10. Yakuchu, L., Morphological Karst Fragment (in Russian), Moscow: Progress Press, 1979, 388.

11. Budel, Die doppelten einebnungsflachen in den feuchten tropen, Z. Geomorph., 1957, 1(2): 223225.

12. McFarlance, M. J., Laterites, in Chemical Sediments and Geomorphology: Precipitates and residua in the near-surface en-

1) Cui Zhijiu, Feng Jinliang, The fossil planation surface of geological history in China, 2000 (unpublished paper).

8/10/2019 02yd0366.pdf

14/15


vironment (eds. Goudie, A. S., Kenneth, P.), London: Academic Press Inc. LTD., 1984.

13. Garner, H. F., Stratigraphic-sedimentary significance of contemporary climate and relief in four regions of the Andes

mountains, Geological Society of America Bulletin. 1959, 70(10): 13271368.

14. Li Qingkui, Xong Yi (Editor in Chief), Chinese Soil (in Chinese), 2nd ed., Beijing: Science Press, 1987.

15. Twidle, C. R., Granitic Inselberg, in Perspectives in Geomorphology, 1982, 1: 127

167.16. King, L. C., Canons of landscape evolution, Geol. Soc. America Bull., 1953, 64, 721752.

17. Bloom, A. L., Geomorphology: A Systematic Analysis of Late Cenozoic Landform, New Jersey: Printice-Hall, Inc., 1998,

349.

18. Guo Jingtang, Ouyang Qing, The Profile Atlas of Chinese Soil (in Chinese), Beijing: China Science and Technology Press,

1991, 52.

19. Budel, Die rilieftypen der flachenspulzone sub-indiens am ostabfall dekans gegen Madras, Colloquium Geographicum,

1965, (8): 25, 33, 9395.

20. Milliman, J. D., Fluvial sediment dischange to the sea and importance of regional tectonics, in Tectonic Uplift and Change

of Climate (ed. Willian, F. R.), New York: Plenum Press, 1997, 239257.

21. Thure, E., Ceiling, Late cenozoic vegetation change, atmospheric CO2, and tectonics, in Tectonic Uplift and Change of

Climate (ed. Willian, F. R.), New York: Plenum Press, 1997, 313327.

8/10/2019 02yd0366.pdf

15/15

CUI Zhijiu et al.: The covered karst, weathering crust and karst (double-level) planation surface Plate

1. The naked karst of the Anduobei Mountain (4950 m a.s.l.), the stone-forest and the stone-wall, the solution bilge formed by

sub-soil (by Li Dewen). 2. The half-naked karst in the Naigu stone-forest of Lunan, the upper part of stone-forest outcrops and

the lower is still covered by soil (2000 m a.s.l.) (by Li Dewen). 3. In the region of Hunan-Guangxi, the stone-forest and karren of

un-naked karst exist and on the ground, there are the peak-forest and the peak-cluster (by Cui Zhijiu). 4. In the Qifeng Town of

Guilin City, the stone-forest formed by sub-soil outcrops due to mining soil (by Li Dewen).

02yd0366.pdf

Documents