Quarries and transportation routes of Angkor monument sandstone blocks

Sandstone blocks are the main construction materials used in the Angkor monuments in Cambodia. However, a thorough study of the quarries has not yet been carried out. We conducted a field investigation of sandstone quarries from the Angkor period at the southeastern foot of Mt. Kulen, which is approximately 35 km northeast of the Angkor monuments. As a result, we discovered more than 50 sandstone quarries. On the basis of the measurements of magnetic susceptibilities and thicknesses (step heights), we found that they were quarried at different times. These four quarrying areas were identified as the quarries D to G inferred by Uchida et al. (2007). In addition we investigated a canal that was identified on satellite images, connecting quarry sites at the foot of Mt. Kulen to the Angkor monuments. The field investigation suggests a high probability that the canal was used for the transportation of sandstone blocks from Mt. Kulen.     

The Construction Process of the Angkor Monuments Elucidated by the Magnetic Susceptibility of Sandstone*

The Angkor monuments in Cambodia are mainly constructed of grey to yellowish‐brown sandstones. No differences in the constituent minerals and in the chemical composition of the sandstones have been confirmed among the monuments. However, we have found their magnetic susceptibility a useful parameter by which to distinguish them. The principal monuments of Angkor Wat, Ta Prohm, Preah Khan, Banteay Kdei and Bayon, constructed from the Angkor Wat period to the Bayon period (from the beginning of the 12th century to the beginning of the 13th century ad ), were investigated in detail using a portable magnetic susceptibility meter. We succeeded in dividing the periods of construction into stages. This elucidated the enlargement process of the monuments and correlated their construction stages.     

Estimation of the construction period of Prasat Suor Prat in the Angkor monuments,Cambodia, based on the characteristics of its stone materials and the radioactive carbon age of charcoal fragments

Prasat Suor Prat in the Angkor monuments, Cambodia, is situated at the east end of the Royal Plaza and consists of 12 towers numbered N1–N6 and S1–S6 that are mainly made of laterite. Sandstone is also used for pediments, door and window frames, and balusters, etc. Until now, it was thought that Prasat Suor Prat was constructed in the Bayon period. However, the characteristics of the stone materials used for the Angkor monuments suggest that Prasat Suor Prat was constructed in the Angkor Wat period. This is supported by the radioactive carbon age obtained for charcoal fragments collected from the soil between the laterite blocks in the N1 tower and also from the stucco on the inner wall of the N2 tower.     

Salt weathering of sandstone at the Angkor monuments,Cambodia: identification of the origins of salts using sulfur and strontium isotopes

The Angkor monuments in northwestern Cambodia, which are primarily made of sandstone, are suffering from deterioration due to salt weathering. In order to elucidate the sources of the salts and salt weathering process, this paper analyzed bulk chemical compositions and S (sulfur) and Sr (strontium) isotopic ratios for the salts and surrounding environmental materials. At places where bats inhabit the structures, various kinds of sulfate and phosphate salts are formed on the surface of the sandstone. The results of the analysis demonstrate that the S and P (phosphorus) components in the salts are primarily derived from bat guano. Moreover, Ca (calcium), which is the major element in the salts, is suggested to be derived from both bat guano and the sandstone. The isotopic data strongly suggests that bat guano is related to salt weathering. Removal of these animal excrements is essential for future conservation of these monuments. On the other hand, exfoliation of sandstone commonly occurs due to crystallization of calcite (CaCO₃) on platform surfaces of pyramid-type monuments. A large amount of Ca in calcite is suggested to be derived from calcite cement of the building sandstone.     

Consideration on the construction process and the sandstone quarries during the Angkor period based on the magnetic susceptibility

Detailed magnetic susceptibility measurement was conducted on the sandstones used for the Angkor monuments constructed in the period spanning the Preah Ko and Angkor Wat styles, and the construction process of the buildings and quarries of the sandstones was considered. Combined with the previous study on the sandstones of the Bayon style [Uchida, E., Cunin, O., Shimoda, I., Suda, C., Nakagawa, T., 2003. The construction process of the Angkor monuments elucidated by the magnetic susceptibility of sandstone, Archaeometry 45, 221–232], the magnetic susceptibility measurement revealed that there were 7 sandstone quarries corresponding to Stages I, II, III, IVa, V, VII and VIIIb during the Angkor period. The sandstones used for the monuments belonging to Stage I show average magnetic susceptibility values ranging from 1.1 to 2.3 × 10⁻³ SI units. In the Bakheng style period (Stage II), the average magnetic susceptibility of the supplied sandstones decreased gradually from around 10 to 1 × 10⁻³ SI units over time. The magnetic susceptibility range of the sandstones used for the monuments of Stage III was from 2.3 to 3.0 × 10⁻³ SI units. In the early Angkor Wat style period (IVb), the average magnetic susceptibility of the supplied sandstones increased over time, reflecting the supply of the sandstones from two different quarries, that is, the quarry corresponding to the Khleang and Baphuon style monuments (Stage IVa), with low average magnetic susceptibilities of 1.1 to 2.4 × 10⁻³ SI units, and the quarry corresponding to the main Angkor Wat style monuments (Stage V), with high average magnetic susceptibilities ranging from 2.8 to more than 4.3 × 10⁻³ SI units. The sandstones of Stage VII show low average magnetic susceptibility around 1 × 10⁻³ SI unit. The sandstones of Stage VId is a mixture of sandstones of Stages V and those of Stage VII. The sandstones with high magnetic susceptibilities are found in the monuments belonging to Stage VIIIb, reflecting the supply from the new sandstone quarry.     

Differentiating Khmer Stoneware Production: An NAA pilot study from Siem Reap Province,Cambodia

We report analytical results for stoneware samples from four excavated Angkor‐period kilns in the Greater Angkor area. Previous work has suggested that establishing distinct chemical signatures for kiln complexes in this region is problematic. The current study highlights the effectiveness of neutron activation analysis (NAA) for differentiating the products of Angkorian kiln complexes; it also confirms the viability of a larger‐scale research programme to understand the relationship between Khmer stoneware production and patterns of distribution across the wider Angkorian territory. Evidence of ceramics excavated at kiln sites but produced elsewhere highlights the complexity of consumption patterns during the Angkorian period.     

TOWARDS A QUANTITATIVE PETROGRAPHIC DATABASE OF KHMER STONE MATERIALS—KOH KER STYLE SCULPTURE

A comprehensive quantitative petrographic database of sandstones used by the Khmers for sculptural purposes would be a helpful tool for archaeologists, museum curators and others interested in pursuing research on early stone usage, geological source and provenance. Towards that end, this paper presents quantitative petrographic analysis of stone materials used in the production of some free‐standing sculptures and architectural elements in the Koh Ker style of the 10th century from the collections of the National Museum of Cambodia and The Metropolitan Museum of Art. These materials are compared to samples from the quarry of Thmâ Anlong near the foothills of the Phnom Kulen, Sieam Reap province. Primary and secondary detrital modes and key grain‐size parameters are used to identify three sandstone types. The free‐standing sculptures are carved from feldspathic arenite and feldspato‐lithic to litho‐feldspathic arenite. Finely carved lintels are worked from a quartz arenite, which is significantly richer in quartz grains and of a finer grain size. The geological source of the two other lithotypes will have to await detailed geological survey of the Koh Ker area accompanied by petrographic study of selected samples from documented quarries. The significance and potentiality of quantitative petrographic study of Khmer stone materials are shown in supporting and integrating archaeological investigations in South‐East Asia.     

A Reconsideration of the Construction Period of the Cruciform Terraces and the Elevated Causeways in the Angkor Monuments,Based on the Magnetic Susceptibility of the Sandstone Blocks*

In this paper, the construction period of the cruciform terraces with columns and the elevated causeways in the Angkor monuments of Cambodia is reconsidered, based on the results of our investigation of magnetic susceptibility and other characteristics of sandstone blocks. From an art‐historical point of view, they are generally considered as modifications in the post‐Bayon style period—the period during the reign of Jayavarman VIII (1243–95 ce ) or later. However, from a lithological point of view, the average magnetic susceptibilities of the sandstone blocks in the cruciform terraces with columns and the elevated causeways are consistent with the rest of the monument. In addition, the characteristics of the sandstone blocks in the cruciform terraces, such as their shape, the orientation of the bedding plane and the stacking method, suggest that they were constructed in the same period as the rest of the monument.     

Nature and provenance of the sandstone used for Bayon style sculptures produced during the reign of Jayavarman VII

Under Jayavarman VII (1182/83-ca.1218 CE) the Khmer empire reached its apex, leaving a heritage of major construction works and unique artistic production. The stone materials of several sculptures produced under his reign were characterized and compared to possible geological sources in northern and eastern Cambodia. The data suggest that a specific type of sandstone, rich in volcanic detritus, was deliberately selected and quarried from a Triassic sedimentary sequence exposed far from Angkor, the main political and economic center at that time.     

Moisture content measurement and surface water absorption test in the inner gallery of Bayon for the conservation of the bas-relief

The bas-relief carved on the sandstone wall in the central part of the inner gallery of Bayon in the Angkor monuments, Cambodia, has been severely damaged mainly due to calcite crystallization. In order to confirm the mechanism of salt weathering and help determine conservation measures for the bas-relief, measurements of the annual change in the moisture content in the bas-relief were conducted. We found that water supplied from the platform behind the bas-relief is the cause of calcite crystallization. It is therefore indispensable for the conservation of the bas-relief to prevent the water permeating from the inside of the platform behind it. As precipitated calcite from the water block pores near the surface of the sandstone, the surface water absorption test is a useful method to evaluate the degree of the salt weathering.     

THE EFFECT OF SALTS ON THERMAL AND HYDRIC DILATATION OF POROUS BUILDING STONE*

Fifteen desalinated sandstone drill core samples from Umm Ishrin Sandstone Formation in Petra (Cambrian age) were used for this study. The samples were mineralogically analysed using X‐ray diffraction and their physical properties were also determined. Samples with similar physical properties and mineralogical composition were taken for further experimental work. After desalination, thermal and hydric dilatation coefficients were measured, then three types of salts (NaCl, KCl and Na₂SO₄·10H₂O), which have high solubility and consequently are the most dangerous to building stone (and are also detected in the sandstone monuments in Petra), were introduced into the samples and their contents were calculated. The results show that salt crystallization in the pores of building stones can increase their thermal dilatation and decrease their hydric dilatation to varying extents, depending on the nature of the salt. The average increase in the thermal dilatation coefficient per unit mass of salt is the lowest for the Na₂SO₄·10H₂O‐salted samples with a value of 5.3%, while the NaCl‐salted samples have the highest value with 7.8% per salt mass. The average percentage of the decrease of the hydric dilatation coefficient is 1061% for Na₂SO₄·10H₂O‐salted samples per mass of salt content; the NaCl‐salted samples have a value of 1510% per mass of salt content, and the KCl‐salted samples almost the same value. For the salt‐free samples, it was found that in climatic conditions with a high temperature range, the deterioration of sandstone due to temperature fluctuation is more effective than that caused by change in the moisture content, while samples with high salt content suffer more from hydric dilatation.     

STUDY ON THE PIGMENTS IN THE CRUCIFORM GALLERY OF ANGKOR WAT,CAMBODIA

In the cruciform gallery of Angkor Wat in Cambodia, red, orange, white and black pigments were widely painted on the surfaces of pillars, walls and friezes. The application sequence of the pigments is different from area to area. The following substances were confirmed from the pigments: hematite (laterite), minium, calcium oxalate hydrates (whewellite and weddellite), Pb–Cl compounds (cotunnite, laurionite and blixite), calcium phosphates (whitlockite), gypsum, hydrocerussite, calcite, anglesite, lead dioxide, azurite and carbon black. The orange pigment (minium) underlies the red pigment (hematite). The former may have been applied at the time of the foundation (the Angkor Wat style period), and the latter in the Bayon style period or later, but mainly before the early 17th century of the current era.     

THE WRITING'S IN THE WALL: A REVIEW OF NEW PRELIMINARY APPLICATIONS OF ELECTRICAL RESISTIVITY TOMOGRAPHY WITHIN ARCHAEOLOGY

Natural processes are known to cause significant damage to archaeological monuments. In fact, the key to understanding the decay of building materials is the internal movement of water through the mineral matrix, which influences the distribution of chemical, physical and biological deterioration processes. Electrical resistivity tomography (ERT) was traditionally used as a surveying tool within archaeology, but a new high‐resolution technique that accurately traces the movement of moisture in building materials could provide a vital tool for understanding the decay of many archaeological monuments. This paper considers current progress, the shift of ERT from soil to rock research and the impact that this development could have on future conservation, using Hertford College (Oxford) and Neolithic rock art (Golden Gate Reserve, South Africa) as case studies.     

Reimagining the City of Fire and Iron: A landscape archaeology of the Angkor-Period Industrial Complex of Preah Khan of Kompong Svay,Cambodia (ca. 9th to 13th centuries A.D.)

In the archaeological literature regional centers often receive far less attention than capital regions and the medieval Khmer Empire (ca. 9th to 15th centuries a.d.) is a classic case in point. At its height, the Khmer Empire stretched across much of mainland Southeast Asia, and it remains the most extensive dominion in the history of the region. To date, however, relatively little archaeological work has been completed outside of the capital of Angkor, and we have a limited understanding of the broader dynamics of the Empire. In this paper we begin to address this lacuna at the remote monumental complex of Preah Khan of Kompong Svay, the largest of all the Angkor-period regional centers. We describe the use of remote sensing and ground survey methods to produce the first comprehensive archaeological map of the site. The map data are used to evaluate conventional interpretations of the site as a major industrial complex, urban center and military outpost. The findings have implications for our understanding of early urbanism, industrial production and imperial expansion in the region.     

TIMBER MONUMENTS,LANDSCAPE ANDTHE ENVIRONMENT IN THE NITH VALLEY,DUMFRIES AND GALLOWAY

This paper considers the impact of landscape and environment upon monuments built during the Neolithic period. Taking a group of timber monuments of Neolithic date in the Nith Valley region, Dumfries and Galloway, it examines their relationship to the topography and environment and seeks to explain their uniquely linear nature, a feature of timber monuments built in this region. It discusses the importance of incorporating plough‐levelled sites into landscape approaches to monuments, the potential impact of vegetation upon visibility patterns, and the value of considering the immediate locations of monuments, arguing that monuments built upon a heightened awareness of landscape topography, arising out of a long‐term relationship with place.     

A GEOARCHAEOLOGICAL STUDY OF THE ANCIENT QUARRIES OF SIDI GHEDAMSY ISLAND (MONASTIR,TUNISIA)

Amongst a large number of ancient quarries scattered along the North African coast, those at Sidi Ghedamsy (Monastir, Tunisia) have supplied building stones of Pliocene age. Two lithofacies have been distinguished in the quarry faces: (i) fine sandy limestone, which has been used in the construction of Roman and Arabic monuments; and (ii) porous and coarse limy sandstone, which is of bad quality for construction. Laboratory analysis results confirm that the exploitation of stone in antiquity was well focused on the levels containing the first type. This is confirmed by geotechnical tests, which show that the fine sandy limestone is harder and less porous than the coarse limy sandstone. Extraction of these stones began in the Roman period. The Romans exploited the quarries using steel tools that permitted the extraction of blocks from several levels. In the eighth century, Arabic quarry workers continued the stone extraction using the same technique, but they produced blocks of small and medium size. Statistical measurements have been done on the quarry faces and on the walls of the Ribat in order to understand the degree of conformity between the dimensions of the extracted blocks and those used for building, and ultimately to attempt to date the quarries and the construction of the Ribat.     

Unearthing an Atlantean myth in Angkor: geoarchaeological investigation of the ‘underwater road’ crossing the Tonle Sap Lake,Cambodia

Of the many myths surrounding the medieval city of Angkor, Cambodia, one of the most obscure but pervasive is the existence of a road built across the Tonle Sap Lake. This road supposedly ran from the Angkorian ‘port’ at Phnom Krom to the temples situated in the Battambang district some 70 km southwest of capital. New geoarchaeological information demonstrates that the ‘road’ is actually a series of localised occurrences of authegenic calcite, which probably formed approximately 5500 years Before Present. Our results demystify this intractable Cambodian legend expand on the dynamic history of this important water body in mainland Southeast Asia.     

DATING THE CONSTRUCTION OF EARLY LATE WOODLAND EARTHEN MONUMENTS AT THE JACKSON LANDING SITE IN COASTAL MISSISSIPPI

Abstract

Middle Woodland and early Late Woodland monuments generally have been interpreted as ceremonial spaces that integrated communities both within and among regions. This article presents information on the early Late Woodland component at the Jackson Landing site, a large site with a platform mound and semicircular earthwork, located on the Mississippi Gulf Coast. Earlier research is synthesized with more recent investigations of the mound to argue that the site’s monuments were built during the early Late Woodland period between approximately A.D. 400 to 700. Determining when Jackson Landing’s monuments were built is important because their construction provides a temporal baseline for regional and, perhaps, interregional social integration along the central Gulf Coast.     

THE FORMATION OF SOCIAL RANK IN THE EARLY NEOLITHIC OF NORTHERN EUROPE

Klavs Randsborg has made important contributions to the archaeology of the Bronze Age and later prehistoric periods, but in the 1970s he also touched upon issues such as the formation of rank in Neolithic societies. In his article ‘Social Dimensions of Early Neolithic Denmark’, he suggested that a hierarchical society arose at the transition from the Early to Middle Neolithic, c. 3300–3200 BC. Since then, excavations and research have resulted in numerous publications about the Neolithic, but only rarely have these examined social development. In this article, the authors continue the debate, sharing the same starting point as Klavs Randsborg, but here approaching the question of emerging social inequality on the background of recent research into the early agricultural societies in Northern Europe, seen in a broader European context. The primary focus is upon burial monuments as manifestations of status and power, and parallels are drawn with similar construction activities amongst present‐day farming communities in such remote areas as the islands of Southeast Asia. The social organisation and ritual customs of these modern farming communities are considered relevant when interpreting the archaeological evidence for early agricultural societies in Northern Europe.     

Urbanism and Residential Patterning in Angkor

The Khmer Empire (9th–15th centuries a.d.), centered on the Greater Angkor region, was the most extensive political entity in the history of mainland Southeast Asia. Stone temples constructed by Angkorian kings and elites were widely assumed to have been loci of ritual as well as habitation, though the latter has been poorly documented archaeologically. In this paper, we present the results of two field seasons of excavation at the temple site of Ta Prohm. Using LiDAR data to focus our excavations, we offer evidence for residential occupation within the temple enclosure from before the 11th century a.d. until the 14th century. A comparison with previous work exploring habitation areas within the Angkor Wat temple enclosure highlights similarities and differences between the two temples. We argue that temple habitation was a key component of the Angkorian urban system and that investigating this unique form of urbanism expands current comparative research on the diversity of ancient cities.