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The ~ 5.5 km sized Jabal Rayah ring structure located at 28° 390 N/37° 120 E in Saudi-Arabia has been classified as a possible complex impact structure located in flat-lying-Paleozoic clastic sediments. Previous, detailed mapping showed that erosional processes led-to a relief inversion, with displaced, folded, and faulted blocks of Silurian to Early-Devonian strata, interpreted to form a ring syncline, now forming a topographically-outstanding, 150 m high ring crest. The drainage toward the center of the structure seems-controlled by a set of radial faults. This central part is eroded to the level of the-surrounding plateau and partially covered with gravel. Analysis of 28 Qusaiba Formation-sandstones showed that at the present outcrop level, the sediments seem devoid of shock-features. Measurement of fold axes in the central part of the structure shows radially-outward plunging fold axes, becoming steeper toward the center, and also fold axes of other-orientation, and folded folds. This fold axis pattern is interpreted as an upward-pointing,-kilometer-sized sheath fold. Assuming an impact scenario and using the present size of the-structure, the minimum central structural uplift is estimated at ~ 500 m, which is consistent-with Qusaiba Formation occupying the center of the ring structure.

Abar al' Uj (AaU) 012 is a clast-rich, vesicular impact-melt (IM) breccia, composed of lithic and mineral clasts set in a very fine-grained and well-crystallized matrix. It is a typical feldspathic lunar meteorite, most likely originating from the lunar farside. Bulk composition (31.0 wt% Al2O3, 3.85wt% FeO) is close to the mean of feldspathic lunar meteorites and Apollo FAN-suite rocks. The low concentration of incompatible trace elements (0.39ppmTh, 0.13ppm U) reflects the absence of a significant KREEP component. Plagioclase is highly anorthitic with a mean of An(96.9)Ab(3.0)Or(0.1). Bulk rock Mg# is 63 and molar FeO/MnO is 76. The terrestrial age of the meteorite is 33.4 +/- 5.2kyr. AaU 012 contains a similar to 1.4x1.5mm(2) exotic clast different from the lithic clast population which is dominated by clasts of anorthosite breccias. Bulk composition and presence of relatively large vesicles indicate that the clast was most probably formed by an impact into a precursor having nonmare igneous origin most likely related to the rare alkali-suite rocks. The IM clast is mainly composed of clinopyroxenes, contains a significant amount of cristobalite (9.0 vol%), and has a microcrystalline mesostasis. Although the clast shows similarities in texture and modal mineral abundances with some Apollo pigeonite basalts, it has lower FeO and higher SiO2 than any mare basalt. It also has higher FeO and lower Al2O3 than rocks from the FAN- or Mg-suite. Its lower Mg# (59) compared to Mg-suite rocks also excludes a relationship with these types of lunar material.