الملخص الإنجليزي
Neoproterozoic glacial strata in Oman are key to the ongoing Snowball Earth discussion, providing a great opportunity to test the hypothesis. The Abu Mahara Group (Huqf Supergroup) is well exposed in the core of the Jabal Akhdar of northern Oman. It contains two glaciogenic units, the Ghubrah Formation (723+16/-10 Ma) and the Fiq Formation (currently undated), that are separated by the volcaniclastic Saqlah Formation. An angular unconformity is present between the Ghubrah and Saqlah formations, indicating a significant time gap between the deposition of the Ghubrah and Fiq glacial successions. The localised occurrence of pillow basalts and more widespread volcaniclastics of the Saqlah Formation, suggests the initiation of a rifting phase, which is considered to have continued during deposition of the Fiq Formation. Given the available geochronology, the Ghubrah Formation may correlate with other glaciogenic successions worldwide attributed to the Sturtian glacial epoch, and the Fiq Formation with younger glaciogenic successions attributed to the Marinoan glacial epoch. Neoproterozoic glaciations appear to have taken place at times of tectonically generated accommodation, suggesting a link between geodynamics, basin development and climate change.
