PROVENANCE OF THE SANDSTONE USED IN THE CONSTRUCTION OF THE KHMER MONUMENTS IN THAILAND

We investigated the sandstone used in the construction of the Khmer monuments situated upon and around the Khorat Plateau in north‐east Thailand in order to clarify the provenance. The sandstones of the 22 investigated Khmer monuments can be classified into three groups. The sandstone of Group 1 is lithic and is derived mainly from the Khok Kruat Formation. This group includes the sandstone used at Phimai, Phnom Wan, Muang Khaek etc. The sandstone of Group 2 is siliceous and can be subdivided into three further groups. The sandstone of Group 2 is considered to have been derived from the Phu Phan, Phra Wihan or Sao Khua Formations. The sandstone used at Muang Tam, Phnom Rung, Sdok Kok Thom, Preah Vihear (Khao Phra Wihan), Narai Jaeng Waeng etc. belongs to Group 2. The sandstone of Group 3 is feldspathic and is correlated with the grey to yellowish‐brown sandstone that is commonly used in the Angkor monuments in Cambodia. This sandstone is used at Wat Phu and Hong Nang Sida in Laos. The above results reveal that the choice of sandstone used for the Khmer monuments, including the Angkor monuments, was dictated by the surrounding geology.     

THE SEARCH FOR THE ORIGIN OF BITUMEN EXCAVATED FROM ARCHAEOLOGICAL SITES IN THE NORTHERNMOST ISLAND IN JAPAN BY MEANS OF STATISTICAL ANALYSIS OF FI–MS DATA*

The origin of bitumen excavated from archaeological sites in Hokkaido, the northernmost island in Japan, was sought by means of field‐ionization mass spectrometry (FI–MS) and gas chromatography – mass spectrometry (GC–MS) of the hydrocarbon components. The field‐ionization mass spectra were decomposed by Z‐numbers into several components, where the Z‐number refers to z in the formula C _n H _2n+z . This is equivalent to the deficit number of H atoms, when compared to the corresponding saturated hydrocarbon, which is related to the number of saturated hydrocarbon rings in alkanes. By use of the spectral intensities of the seven alkane components in each sample, multiple discriminant analysis was employed for the data of raw bitumen samples and excavated samples from archaeological sites. Based on this method and the gas chromatogram type, the following bitumen trade in the prehistoric age of Japan was elucidated: bitumen from Niigata, one of the main sources on the main island of Japan, spread to the north in 2000 bc , probably via the coastal zone, and reached a small island near the north end of Hokkaido. Bitumen from Sakhalin reached the central lowland in Hokkaido, but it went no further. Bitumen from Akita, another main source on the main island, spread over northern Honshu much earlier and reached the Oshima peninsula, the southwestern part of Hokkaido. The Akita bitumen scattered into the central lowland after the Niigata and Sakhalin bitumen. This area is believed to be the place where people from the south and the north met in those periods.     

Rapid On‐site Topographic Mapping with a Handheld Laser Range Finder for a Geoarchaeological Survey in Syria

A digital elevation model and a topographic map of an archaeological site in Syria were created from a field topographic survey with a handheld laser range finder and data post‐processing using a notebook personal computer with Geographical Information System software. The method enabled rapid on‐site topographical mapping even under technical and political restrictions in the country. In an area of about 1 km², coordinates of random points on the land surface were measured, and a DEM with a 10 m interval grid was generated from the point cloud using Kriging interpolation. The DEM enables various topographic representations to be constructed, such as contour lines, cross sections and slope distribution maps. The DEM‐derived contour lines with a 1 m interval were combined with vector data showing roads and buildings to provide a topographic map. Topographic cross sections created from the DEM generally agree with sections surveyed with a hand level and a measurement tape. The obtained DEM and map are useful for preliminary field research.