A comparative geochemical study of bituminous boat remains from H3, As-Sabiyah (Kuwait), and RJ-2, Ra's al-Jinz (Oman)

This paper presents a geochemical analysis of fragments of bituminous amalgam from H3, As‐Sabiyah (Kuwait), and RJ‐2, Ra's al‐Jinz (Oman). The fragments bear barnacles on one side and reed impressions on the other, and are thought to have been part of the coating of reed‐bundle boats. The material from H3 dates to between 5300–4900 BC, while that of RJ‐2 dates to 2500–2100 BC. Samples from both sites were geochemically compared to archaeological and ethnographic material from Kosak Shamali (northern Syria, c.5000–4400 BC), RH‐5 (Oman, 4400–3500 BC) and Baghdad (central Iraq, 1900 AD). The composition of the bituminous amalgams was studied in detail. Rock‐Eval Pyrolysis gave a measure of Total Organic Carbon in the samples, and allowed an initial comparison of the data sets using various parameters. Examination of the proportions of soluble and insoluble organic matter allowed an assessment of the quantity of vegetal matter added to the bitumen to make the bituminous amalgam. The composition of the Ra's al‐Jinz material was studied using X‐Ray Diffraction analysis and thin‐section petrography, in order to assess the proportions of various minerals in the bituminous amalgams. It was concluded that the recipe for the bituminous mixture used to coat reed‐bundle and wooden boats did not differ significantly from that commonly used to make ‘mortar’ for architectural purposes in Mesopotamia. Traces of animal fats or fish oils were not found in the analysed Ra's al‐Jinz material, in contrast to previous hypotheses regarding the composition of the mixture. Comparison of the gross composition of extractable organic matter (the constituents of pure bitumen, soluble in chloroform or dichloromethane) showed the progressive effects of weathering on the samples. The isotopic composition of the bituminous material from H3 and the other sites was then compared to that of bitumen seeps and crude oils from Mesopotamia, Iran and Oman. The most significant result is that the material from As‐Sabiyah originated in Kuwait, at a surface seep at Burgan, while the material from Ra's al‐Jinz had a source in northern Mesopotamia.     

A geochemical study of bituminous mixtures from Failaka and Umm an-Namel (Kuwait), from the Early Dilmun to the Early Islamic period

This paper is the last in a series presenting geochemical analyses of fragments of bituminous mixtures excavated from archaeological sites in Kuwait. The first was devoted to bituminous boat remains from the Ubaid‐related Neolithic site of H3, As‐Sabiyah, while the second dealt with bituminous amalgams from the Partho‐Sasanian site of ^cAkkaz, a former island now joined to the south side of Kuwait Bay. This, the third, refers to bitumen‐bearing samples from two other islands, Failaka and Umm an‐Namel, and covers a time span including the Early Dilmun period, the Kassite period and the Hellenistic to Early Islamic periods. The composition of the bituminous amalgams was studied in detail. The proportions of soluble and insoluble organic matter as well as vegetal organic matter were evaluated. Mineralogical composition by X‐Ray diffraction and thin‐section analysis was used to estimate the mineral input in the bituminous mixtures. It can be confirmed that the recipes used in the preparation of these bituminous amalgams comply with those traditionally used in antiquity, as seen at many sites in Mesopotamia and the Gulf. Analysis of the soluble organic matter, and especially its ‘‘saturates’’ fraction, provided sterane and terpane distributions and the measurement of diagnostic molecular ratios. These data, complemented by the isotopic composition of asphaltenes, allowed the identification of the sources of the bitumen, by calibration with numerous references from Iran and northern Iraq (oil seeps, bitumen from archaeological sites). It was established that the bitumen from Failaka and Umm an‐Namel was mainly imported from central Iraq (Hit‐Abu Jir) and northern Iraq (around Mosul). One sample of oil‐stained sand, dating to the Early Dilmun period, originated from Burgan and thus documents small‐scale imports from inland Kuwait. These results, and those of previous analyses, agree with the geopolitical context of the Early Dilmun, Kassite and Hellenistic periods, and the maritime trade routes that linked Mesopotamia to the settlements of the Gulf and beyond. The paper concludes with an overview of recent bitumen provenance analyses, and discerns chronological patterns in the distribution of Iraqi and Iranian bitumen in the Gulf and Indian Ocean, from the Neolithic to the Islamic periods.