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Oil shale deposits with over 70 billion tons of proven reserves are considered one of Jordan's most important sources of energy. The current study investigated the mineralogy, geochemistry, and spectral characteristics of the Wadi Abu Ziad oil shales in northern Jordan. The mineralogical composition of the collected samples was analyzed using X-ray diffraction (XRD). Total organic matter (TOM) and calcium carbonate (CaCO3) contents were also determined. The spectral characteristics of oil shales were examined using a GER 3700 Spectroradiometer (0.35 to 2.5 µm) and Fourier transform infrared spectroscopy (FTIR) (4000 to 400 cm−1). XRD analysis revealed that the samples are composed primarily of quartz, calcite, and apatite. The average TOM and CaCO3 contents in the study area are 13.91% and 16.73%, respectively. The absorption features of oil shale samples are at 1.41 µm and 1.90 µm (H2O), 1.76 µm (C–H), 2.20 µm (Al–OH), and 2.33 µm (CO3). The FTIR absorption spectrum exhibits the absorption bands that characterize kaolinite, quartz (SiO2), calcite (CaCO3), and organic compounds in the oil shale samples. Spectroscopic analysis is a useful tool for identifying the mineralogical composition of oil shales and helps oil shale exploration using multispectral and hyperspectral remote sensing data.

Oil shale deposits of the mid-Eocene Wadi Shallala Formation in northern Jordan consist of organic-rich limestones and chalks. These organic-rich deposits are exposed at the surface near Wadi Ash Shajara, in a 12-m-thick outcrop. For this study, a total of 21 oil shale samples were analysed for bulk elemental geochemistry, inorganic geochemistry, organic geochemistry and microfacies analysis. Three microfacies types were recognised: pelagic mudstone/wackestone, foraminiferal packstone and bioclastic packstone/wackestone. The observed cyclicity of these microfacies in the study area indicates fluctuations in depositional conditions in Neo-Tethys during the mid-Eocene. A shallow-water, calm, restricted marine environment with limited water circulation and low energy currents evolved into a deeper-water environment with open circulation at or just below the wave base. Wadi Shallala Formation in Wadi Ash Shajara composes mainly of chalk (CaCO3 = ~92 wt%) with a TOC of up to 5 wt % and comprises abundant calcareous nannofossils, foraminifera and ostracods as well as non-clastic components like calcitic fragments. The sulphur content of the analysed samples is significant (1.24 wt %) and is associated with the organic matter. Redox-sensitive elements (Fe, Ni, Zn, S and Zr) are enriched in the oil shale samples, indicating an anoxic depositional environment fluctuating between euxinic and sub-euxinic. These fluctuations in depositional conditions of the basin are a result of many factors such as climate, and tectonisms affected deposition of oil shales during Middle Eocene time.

A circular structure, 5.5 km in diameter, in central eastern Jordan has been interpreted as a large meteorite impact structure. The age of the Waqf As Suwwan impact is poorly constrained. By examining calcareous nannofossils from the sediments exposed in this structure, an age model of the timing of the event has been obtained. A total of 81 smear slides from two cores (BH-1, BH-2) penetrating the sediments of the central structure were prepared in order to obtain a biostratigraphic age for the post-impact sediments. The calcareous nannofossils assign sediments below the breccias of the core BH-1 an age of late Campanian to late Maastrichtian and a mixture of late Maastrichtian to early Eocene ages in the breccia horizon, while core BH-2 is of early Maastrichtian to late Maastrichtian age. The upper part of the sediments, removed in from adjacent area, consists of breccia components. The presences of calcareous nannofossil marker assemblages suggest that these components were derived from two different sources: a Cretaceous and a Paleocene-Early Eocene one. The deposition of the breccia resulted from gravitational collapse of water-saturated sediments in two stages; the earlier of these was more intensive than the latter. The stratigraphic framework and the presence of reworked Cretaceous and Paleocene calcareous nannofossils within Paleogene nannofossil Zone NP12/NP13 suggests an early Eocene age for the impact. The upper part of the Cretaceous sediments was thermally altered by the impact causing partial or complete dissolution of the calcareous nannofossils. This caused overgrowth for the more resistant species, while others were dissolved.