Abstract This paper proposes a model for glaciation in Oman during the late Palaeozoic ice age (LPIA) based on sedimentological and provenance analyses of the Late Carboniferous–Early Permian Al Khlata Formation, exposed in the Huqf, Oman. The results demonstrate a complex pattern of glaciation across Oman, not fully recognized in previous models. Striated glacial pavements provide evidence for two phases of ice advance: a phase of ice sheet advance towards the NE, and a second and probably younger phase where an ice centre localized on the Huqf High flowed towards the SW. The stratigraphy is constrained by previous palynological studies and is subdivided into three units, from oldest to youngest: ‘early’ AKP5, ‘late’ AKP5 and AKP5/P1. ‘Early’ AKP5 palaeogeography is characterized by ice-contact glacial lacustrine and deltaic sedimentary environments along the western margin of the Huqf High. Meltwater discharge flowed into the lake from ice margins located to the east, upon the Huqf High, recorded by progradational delta and fan complexes. ‘Late’ AKP5 palaeogeography is characterized by pro-glacial fluvial-deltaic outwash braidplains that record high-magnitude meltwater discharge from an ice margin located to the SW of the study area. The youngest undifferentiated AKP5/P1 palaeogeography is characterized by re-establishment of ice-contact glaciolacustrine conditions.

Abstract We propose the name Northwest Dingle Domain for the enigmatic Old Red Sandstone terrane whose tectono-sedimentary evolution has perplexed generations of geologists. The Domain remained largely misinterpreted, unappraised or simply disregarded, and its fundamental impact on regional basin dynamics was grossly overlooked. The Northwest Dingle Domain is largely structurally constrained between two ENE-trending Caledonian structures: the North Kerry Lineament and the Fohernamanagh Fault. It comprises four unconformity-bounded Groups: the Lower Devonian Smerwick Group; the Middle Devonian Pointagare Group; and the Upper Devonian Carrigduff and Ballyroe Groups. Their fluvial–aeolian, and locally tidal, sedimentation patterns profile Late Caledonian transpression to Mid–Late Devonian extension. The inherent primary structural control on basin location, development, geometry, sedimentary-fill and preservation is manifest in the Northwest Dingle Domain. The Acadian emplacement of the Smerwick Group set the foundations of the Northwest Dingle Domain. The Smerwick Group documents sandy and gravelliferous ephemeral-fluvial and erg-margin aeolian processes on an ancient terminal fan(s). The Pointagare Group is cogenetic with the Caherbla Group of south Dingle. Together they record the renewed influx of coarse-grained sediment in the form of transverse alluvial fans and axial braidplains in response to increased tectonism followed by overstep of an erg complex. The Pointagare–Caherbla basin model highlights the fundamental structural control on basin topography, palaeodrainage patterns, provenance, palaeowind directions and sedimentation style in tectonically-active extensional basins.

Abstract The high-quality, laterally continuous coastal exposures of the Moor Cliffs Formation have allowed a highly detailed 2D reconstruction of the floodplain sediments and their contained pedogenic horizons to be made. The thick siltstone packages were actively deposited as finely laminated and rippled sheets, or as intraformational clasts forming larger bedforms. It is proposed that the unusual sediment geometries preserved are intimately related to the timing of land plant colonization of the Old Red Sandstone continent. Channels were extremely broad with low relief and flow over interfluvial areas was common. Evidence for ephemerality and regular desiccation is also closely related to the lack of rooted vegetation and not to palaeoclimate, which is postulated to be warm and seasonally wet. The low net sandstone (< 10%) fluvial sediments are the product of deposition by shallow, high width to depth fluvial ‘channels’ flanked by broad, low-relief silty plains on which Vertisols formed. The reconstructions of this fluvial system reveal distinctive and systematic vertical and lateral variations in floodplain architecture and palaeosol development. Pedogenic maturity consistently increases with distance both vertically and laterally from channels. The vertical patterns of palaeosol development and maturity suggest that autocyclic processes of aggradation and avulsion predominated.

Abstract The 2.3 km thick Lower Devonian Battery Point Formation conformably overlies shallow marine sandstones of the York River Formation and coarsens upward into proximal braidplain deposits of the Malbaie Formation. Whereas the lower part consists largely of west to northwesterlydraining distal sandy braidplain and meandering fluvial systems, the uppermost Fort Prevel Member (760 m thick) contains a variety of fluvial deposits formed in direct (tectonic) and indirect (climatic) response to early Acadian deformation. Four lithofacies associations are recognized in the Fort Prevel Member. The lowest (Association 1, 80 m thick) consists of isolated and amalgamated sheet sandstones with parallel lamination and trough crossbedding deposited in low sinuosity, north to northeastwardflowing, sandbed fluvial channels. Association 2 (235 m thick) largely comprises laterally and vertically variable thin channelfill and sheetflood sandstones deposited on extensively desiccated ephemeral mudflats. In the lower part, these sediments interbed with mainly parallellaminated, amalgamated sheet sandstones, with crosscutting channel fills flowing toward the north and northeast. At the top of the association, axial ESEflowing, more perennial fluvial systems traversed ephemeral mudflats. Association 3 (165 m) consists of stacked planar and trough crossbedded sandstones deposited in major ESEflowing axial drainage systems, overstepped by more proximal, though still axially flowing, sandy braidplain facies of Association 4 (260 m thick). A tectonic model is proposed for the reversal in dispersion direction of axial drainage systems in the Battery Point Formation, incorporating recent views on the Acadian Orogeny as involving oblique continental collision of several microcontinents. Collision with the St. Lawrence promontory initiated subsidence in the Gaspe Basin and supplied longitudinal fluvial systems flowing westward into a coastal embayment during lower Battery Point Formation time. Later collision of the New York promotory to the southeast reversed basin axis slope during deposition of the Fort Prevel Member. This supplied sediment longitudinally eastward and southeastward into an uplifted, probably enclosed semiarid basin. Marginal basin uplift to the south later generated the Malbaie Formation conglomerates.