The organic geochemistry of the Hasbeya asphalt (Lebanon): comparison with asphalts from the Dead Sea area and Iraq

The Hasbeya asphalt from Lebanon and the Mezar-1 asphalt from the Golan Heights were analyzed using current tools of petroleum geochemistry, namely isotopic analyses (δD, δ13C, δ34S) and molecular sterane and terpane parameters. The geochemical properties of these asphalts were compared to several other asphalts from Israel (floating blocks of the Dead Sea, Massada, Nahal Heimar, IPRG). All the asphalts belong to the same genetic family (e.g. high gammacerane and high steroid contents, no diasteranes) and originate from Senonian (Upper Cretaceous) organic-matter-rich carbonate source rocks deposited in an anoxic or dysoxic (perhaps hypersaline) palaeoenvironment. This family of asphalts is well differentiated from another famous asphalt from the Near East, the Hit-Abu Jir asphalt from Iraq. The Hasbeya asphalt is slightly biodegraded, whereas the Mezar-1 asphalt was affected by more severe biodegradation (occurrence of 25-nor-hopanes). Isotopic ratios of asphaltenes were found to be useful in allowing differentiation of asphalts from the same genetic family. This study completes the existing knowledge on Dead Sea asphalts by demonstrating that similar asphalts may be identified within a much larger geographic area, including the Golan Heights and Lebanon. These results raise the question of whether some of the archaeological asphalts that are found in the southern Fertile Crescent (Egypt, Israel, Syria, etc.) and which were assumed to be of Dead Sea origin, may actually have come from Hasbeya.