Petrological Characteristics and Supply Suggestion for

Restoration Stones in Hong Nang Sida Temple, LAO PDR

Chan Hee Lee

, Jun Hyoung Park

, Yu Gun Chun

and Han Seul Kim

Department of Cultural Heritage Conservation Sciences, Kongju National University, Gongju, 32588, Republic of Korea

Korea Cultural Heritage Foundation, Seoul, 06153, Republic of Korea

Cultural Heritage Conservation Science Center, National Research Institute of Cultural Heritage, Daejeon, 34122,

Republic of Korea

Keywords: Hong Nang Sida temple site, Sandstone, Petrological characteristics, Provenance interpretation, Homogeneity

investigation.

Abstract: With significant historical and academic value, Hong Nang Sida Temple in Lao PDR was designated as a

UNESCO world cultural heritage along with nearby Vat Phou Temple. In this study, we discuss the

provenance of stones constructing the Hong Nang Sida temple and way to secure it. The main temple in Hong

Nang Sida is made with sandstone and siltstone, and they are divided into gray sandstone, grayish-green

siltstone, grayish-green sandstone, dark gray sandstone, etc. according to their color. By assuming that they

were extracted from nearby Mt. Phu Nak, Douangdy quarry and Vat Chompet quarry, specimens were

collected to review the homogeneity with the stones in Hong Nang Sida site. Considering the possibility that

they were imported from a long distance, stones from Thailand were also compared. The study on the

homogeneity of stones revealed that it would be the most desirable to use rocks from Mt. Phunak as alternative

stones for restoration of the main temple. However, it is hard to get sufficient amount of alternative stones for

restoration, because Mt. Phu Nak was designated as world heritage protection area. Thus, it is proper to secure

alternative stones from Douangdy and Vat Chompet quarry, considering the geochemical homogeneity

including color and deposition structure as well as procurement possibility.

1 INTRODUCTION

Along with Cambodia, Vietnam, Myanmar, Thailand

and Lao PDR was a country that the ancient Khmer

Empire ruled historically and culturally. There are a

number of remains related to Khmer including

Angkor in Cambodia, My Son sites in Vietnam,

Phimai temples in Thailand and Vat Phou sites in

Laos. ‘Vat Phou Temple and ancient dwelling site in

Champasak cultural landscape’ including Vat Phou

Temple and Hong Nang Sida in Laos is a popular

tourist destination in southern Laos designated as the

UNESCO World Cultural Heritage in 2001.

Major remains of the Champasak cultural

landscape are Phou Kao, Vat Phou Temple Complex,

Hong Nang Sida area including Ancient Road as well

as Thao Tao Temple, Temples and Inscriptions,

Ancient City, Tomo Temple, Other sites on the

Champasak Plain.

The study point, Hong Nang Sida, is located on

the about 1.5km southside from Vat Phou main

temple. Hong Nang Sida temple consists of platform–

mandapa–antarala-cella; cella and antarala lost its

original shape because of destroyed upper part.

Moreover, stones in the upper part are being piled up

around the temple, making it impossible to enter

inside.

Therefore, it is expected that the result of this

study provides basic scientific data to restore the

Khmer remains. In this study, we performed material

analysis on rocks consisting of Hong Nang Sida,

study on securing alternative stones and procuring

stones through analysis on place of origin of main

temple rocks. This is essential for supply and demand

of alternative stones for maintenance and restoration

of Hong Nang Sida in the future and preservation of

reused stones.

Lee, C. and Kim, H.

Petrological Characteristics and Supply Suggestion for Restoration Stones in Hong Nang Sida Temple, LAO PDR.

DOI: 10.5220/0010294700003051

In Proceedings of the International Conference on Culture Heritage, Education, Sustainable Tourism, and Innovation Technologies (CESIT 2020), pages 64-68

ISBN: 978-989-758-501-2

2 METHODOLOGY

Sandstone at the Hong Nang Sida temple was

observed with naked eyes and portable microscope,

The petrographical characteristics were recorded to

analyze by sampling proper amount of specimens

collected for scientific analysis. To assume place of

origin of the sandstone consisting of the main temple,

geological distribution near the Hong Nang Sida was

explored in detail, and areas expected to have the

same rocks were studied. During the research process,

several samples were secured from Mt. Phu Nak and

Douangdy and Vat Chom Phet quarry, and even rock

samples confirmed to be imported from Thailand

were analyzed for homogeneity test.

Figure 1: Terrain and sampling points around the Hoang

Nang Sida in LAO P.D.R.

In this study, various analysis were conducted for the

homogeneity test, and these method were an

internationally proven research method that has been

applied to various cultural heritages(Lee at el., 2007;

2010; Lee et al., 2006; Lee and Yi 2007; Uchida et

al., 2007). The magnetic susceptibility and

chromaticity measuring were performed to discuss

the homo-geneity for samples. For quantitative

analysis of major constituents and trace and rare earth

elements, geochemical analysis was performed

through using INAA, ICP-MS, and ICP-AES, etc.

3 RESULT AND DISCUSSION

3.1 Petrological Characteristics

Sandstone, consisting of the Hong Nang Sida temple,

can be divided into gray sandstone, grayish-green

siltstone, grayish-green sandstone and dark gray

sandstone in detail. Northside in the temple is mostly

covered with grayish-green sandstone and siltstone,

but the platform, eastside in the temple, has

concentrated with dark gray sandstone; Thus, at least

two stone types were used to construct the temple.

However, these sandstones have a similar particle

size of 5mm regardless of their color. Also, the

mineral composition is similar. Quartz is the major

mineral, and a small amount of feldspar and mica are

obersved. Siltstone consists of fine particles with the

particle size of around 0.1mm, and quartz accounts

for the most. As a minor mineral, biotite is observed

in a linear structure.

Figure 2: Status of the Hong Nang Sida temple and

sandstone. (A) The whole view of the temple. (B)

Stereoscope photograph of gray sandstone.

Located in the northwest of Hong Nang Sida, Mt.

Phu Nak has exposed bedrocks lying scattered and a

lot of traces of quarrying. These traces are observed

with a rectangle of dozes cm × hundreds cm at various

spots of outcrops. In the Mt. Phu Nak, grayish-green

siltstone, dark gray siltstone and dark gray sandstone

are mostly observed. Although most of them have

similar petrographic features to rocks used in the

main temple of Hong Nang Sida, there is partially a

slight difference in stone color, refined structure and

particle size.

Figure 3: Photographs of the sandstone in the Phu Nak

mountain. (A) outcrop and quarry trace. (B) Stereoscope

photograph of greenish gray sandstone.

Petrological Characteristics and Supply Suggestion for Restoration Stones in Hong Nang Sida Temple, LAO PDR

It is essential to secure places to supply almost the

same rocks to stones constituting the main temple of

Hong Nang Sida in mass. This study investigated

rocks from Douangdy quarry, which is about 20 km

north from the Hong Nang Sida, and quarry near Vat

Chompet Temple that is approximately 20 km

northwest. These areas enable mass quarrying, and

quarrying has been conducted until recently.

Moreover, the rocks belong to the same index horizon

of the same period to the sandstone constituting Mt.

Phu Nak and Mt. Phou Kao, which are known for the

place of origin stone in Hong Nang Sida. The quarried

rocks were very heterogeneous, but in the part of the

massive structure, they showed high homogeneity

with the rocks of the temple.

Figure 4: Photographs of current quarry. (A) DouAngdy

quarry. (B) Vat Chompet quarry.

The north palace of Vat Phu temple was restored

using the stones from Thailand. They had various

colors: pinkish gray siltstone, gray siltstone, purple

siltstone, and pale yellow sandstone. The color,

texture, and structure of the rock are all different, and

the matrix contains calcite.

3.2 Chromaticity

Figure 5: Diagram showing chromaticity of sandstones.

In the study, quantitative chromaticity of samples

was measured using MINOLTA CR-300 colorimeter.

L* values of sandstones from Hong Nang Sida site

were 46.26 to 64.89 (average 57.68), a* –1.84 to 3.74

(average 0.60), and b* 5.55 to 8.70 (average 7.04).

Each sandstone samples from Mt. Phu Nak,

Douangdy and Vat Chompet quarry, have the similar

chromaticity to Hong Nang Sida samples.

On the other hand, some stones from Thailand

showed L* of 55.99 to 69.28 (average 62.30), a* of

0.18 to 9.62 (average 4.71), and b* of 4.82 to 16.13

(average 10.54), a wide range of chromaticity. They

had relatively high redness and yellowness compared

to other samples, and the deviation among samples

also was significant.

3.3 Magnetic Susceptibility

The magnetic susceptibility of Hong Nang Sida

sandstone showed distribution of 0.017 to 0.228 (×10

SI unit), and the average was 0.115(×10

-3

SI unit).

Although some samples of Mt. Phu Nak, Douangdy

and Vat Chompet quarry exceeded the magnetic

susceptibility measurement results of Hong Nang

Sida, most of them showed similar distribution. All

Thailand sandstone has less than 0.100(×10

-3

SI unit),

showing the inhomogeneity.

Figure 6: Diagram showing magnetic susceptibility of

sandstones.

3.4 Geochemical Characteristics

This study conducted analysis on major elements,

rare earth elements, compatible and incompatible

elements to discuss the place of origin of rocks in

Hong Nang Sida and homogeneity to secure

alternative rocks. As a result of the analysis of major

elements, most sandstone used in the Hong Nang Sida

showed the similar geochemical data, despite the

difference of rock floor, and Mt. Phu Nak, Douangdy

quarry and Vat Chompet quarry also showed the

similar behaviour characteristics on all elements.

Stones from Thailand, show different behavior

CESIT 2020 - International Conference on Culture Heritage, Education, Sustainable Tourism, and Innovation Technologies

characteristics: Al

lacks, CaO is enriched, and the

contents of overall elements lack.

Differences in geochemical characteristics are

also observed in Rare Earth Elements, Large Ion

Lithophile Elements, and High Strength Filed

Elements, but it is difficult to distinguish compared to

the analysis of major elements. It was classified into

three types based on geochemical characteristics, and

the same characteristics as those of the Hong Nang

Sida temple were set as type-A. As a result, sandstone

in Mt. Phu Nak, Douangdy and Vat Chompet quarry

is included in type-A, and has similar geochemical

characteristics.

Figure 7: Classification in geochemical characteristics as

three types.

4 CONCLUSION

The principle of repairs and maintenance of world

heritage has to be pursuit the original shape for

restoration without damaging completeness and

authenticity. It will be ideal restoration of the main

temple using the Mt. Phu Nak sandstone, which has

evidence of quarry and the most homogeneous with

the Hong Nang Sida rocks. However, since this area

is designated as world heritage protection region, It is

difficult to obtain enough alternative rocks to restore

the temple.

Accordingly, it is required to decide whether the

stones are proper for restoration by comparing the

type and color, sedimentation structure, mineral

compositions, geochemical behavior and etc. This

study analyzed stones from Douangdy quarry, Vat

Chompet quarry and Thailand except for Hong Nang

Sida Temple and Mt. Phu Nak, and evaluated the

appropriateness of as alternative rocks for restoration.

As a result, it is proper to secure alternative stones

from Douangdy and Vat Chompet quarry,

considering the geochemical homogeneity, color and

deposition structure as well as procurement

possibility.

Stones imported from Thailand were all different

in chromaticity, mineral compositions and

geochemical behavior. Using the stones will not only

be heterogeneous with existing members but also

cause different erosion due to difference in

weathering strength caused by mineral compositions.

As such, using the stones as an alternative should be

avoided.

Figure 8: Presumed source and transportation route of the

sandstone properties in the Hong Nang Sida.

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CESIT 2020 - International Conference on Culture Heritage, Education, Sustainable Tourism, and Innovation Technologies