Bitumen samples, sources

The elemental analysis of oil sand bitumen (extra heavy oil) has also been widely reported (Speight, 1990), but the data suffer from the disadvantage that identification of the source is too general (i.e., Athabasca bitumen which covers several deposits) and is often not site specific. In addition, the analysis is quoted for separated bitumen, which may have been obtained by any one of several procedures and may therefore not be representative of the total bitumen on the sand. However, recent efforts have focused on a program to produce sound, reproducible data from samples for which the origin is carefully identified (Wallace et al., 1988). It is to be hoped that this program continues as it will provide a valuable database for tar sand and bitumen characterization. 

No complete surveys of either bitumen sources or ancient townsites exist. Geographical coordinates of the sources of all samples described in the present work are given in Table I along with the names of the investigators who recovered them and from whom they were obtained. Of the 14 archaeological sites and 8 locations for possible source materials listed, asphalts from 7 had been studied previously, and 17 were included in the present investigation. 

Early analyses for 14 archaeological asphalts from various sources are collected in Table II. The late R. J. Forbes of the Shell Laboratories in Amsterdam contributed most, with samples from Ur and Babylon as well as from Mohenjo Daro in the Indus Valley far to the east (3). Analytical methods were not described clearly, yet several similarities in the results of diflEerent analysts are evident. The bitumen content of nine... 

Bitumen Sources. Analyses of possible source materials are given in Table VIII. The seepages of Hit and such bitumen lakes as Abu Gir are the traditional sources for asphalts of the cities of lower Mesopotamia. Despite repeated attempts, samples could not be obtained for analysis. 

All other sources in Table VIII are from Zagros locations, especially the foothills and valleys from Ain Gir to Bebehan from which multiple samples were obtained. The seepages of Ain Gir contained more bitumen and less sand than the dried and rock asphalts, which are much alike. Weathered and unweathered rock asphalts from Mordeh Pel were hardly distinguishable, as were the Bebehan samples in other respects than bitumen content. The samples from M-i-S, Mordeh Pel, and Rijab are probably too lean to have been used as source materials. But the similarities at Ain Gir and Mordeh Pel suggest that the bitumen in any seepages at other sites would have resembled that in the asphalts there. 

Other samples are difBcult to correlate with the sources examined in Table VIII because many sources of minerals as well as bitumens that could have been used are as yet unknown or unstudied. 

Feedstock Source. Three feedstocks were used in this study. All were derived from Uinta Basin, Utah Tar Sand deposits. A Sunnyside bitumen was solvent extracted by procedures previously reported (6) from a freshly mined sample obtained from the old Asphalt Quarry northeast of Sunnyside, Utah. An Asphalt Ridge bitumen was extracted similarly from a sample freshly mined from... 

Fig. 5. Monterey Formation cores (a) bitumen extracted from the source samples versus depth and (b) bitumen profile of d versus r ax from Rock Eval on whole sample. Samples taken from a drilled well of the same location as reported in Table 1 and Baskin and Peters (1992).

Fig. 2. GC-MS key ion traces for the alkanes (m/z 57) in the bitumen of the unaltered and thermally altered samples. Temperatures are shown amb, source composite (all sample 1) numbers refer to carbon chain length ip, isoprenoid Pr, pristane Ph, phytane.

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