Maastrichtian to Tertiary sedimentary rocks outcrop extensively around the periphery of the Oman Mountains. They form part of a geologically distinct suite of strata deposited after obduction of the Semail ophiolite and thrusting of the Hawasina and Sumeini imbricates onto the eastern edge of the Arabian plate. The lithostratigraphy of Maastrichtian and early Tertiary rocks of the central and northern Oman Mountains is revised and a number of new formations are erected. The proto-Oman Mountains were emergent in the early Maastrichtian and were subject to subaerial erosion and weathering. NW and W of the mountains, gradual subsidence followed during the Maastrichtian, allowing for formation of a transgressive, onlapping sequence represented by the Qahlah (fluviatile to shallow marine terrigenous clastics) and Simsima (shallow shelf carbonate) Formations. More rapid subsidence NE of the mountains produced fan delta and submarine debris flow/turbidite apron sequences comprising the Al Khawd and Thaqab Formations respectively. A low-angle unconformity separates Tertiary strata from older units. During the Palaeogene, basinal and slope facies with debris flows and turbidite sequences were deposited directly upon the unconformity surface in rapidly subsiding basins NW (Muthaymimah Formation) and NNE (Ruwaydah Formation) of the Oman Mountains. Elsewhere, shallow carbonate shelf facies were extensively developed in less rapidly subsiding areas during the Palaeogene. The Palaeocene and early Eocene is represented by the Jafnayn Limestone Formation. This is succeeded and overlapped by a variety of later Eocene units. ENE and E of the mountains early Eocene regression is marked by restricted facies of the Rusayl Formation. Overlying the Rusayl Formation are shallow, open shelf limestones of the Seeb Formation which is rich in alveolinid and nummulitic foraminifera. On the Arabian side of the mountains the Rusayl Formation is not developed and the Jafnayn Formation is succeeded either by the Seeb Formation or fine-grained, faunally restricted limestones and marls of the Fahud Beds, which represent intra-shelf facies.

Organisms provide some of the most sensitive indicators of climate change and evolutionary responses are becoming apparent in species with short generation times. Large datasets on genetic polymorphism that can provide an historical benchmark against which to test for recent evolutionary responses are very rare, but an exception is found in the brown-lipped banded snail (Cepaea nemoralis). This species is sensitive to its thermal environment and exhibits several polymorphisms of shell colour and banding pattern affecting shell albedo in the majority of populations within its native range in Europe. We tested for evolutionary changes in shell albedo that might have been driven by the warming of the climate in Europe over the last half century by compiling an historical dataset for 6,515 native populations of C. nemoralis and comparing this with new data on nearly 3,000 populations. The new data were sampled mainly in 2009 through the Evolution MegaLab, a citizen science project that engaged thousands of volunteers in 15 countries throughout Europe in the biggest such exercise ever undertaken. A known geographic cline in the frequency of the colour phenotype with the highest albedo (yellow) was shown to have persisted and a difference in colour frequency between woodland and more open habitats was confirmed, but there was no general increase in the frequency of yellow shells. This may have been because snails adapted to a warming climate through behavioural thermoregulation. By contrast, we detected an unexpected decrease in the frequency of Unbanded shells and an increase in the Mid-banded morph. Neither of these evolutionary changes appears to be a direct response to climate change, indicating that the influence of other selective agents, possibly related to changing predation pressure and habitat change with effects on micro-climate.

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Variations in Aptian carbonate platform growth and associated turnover among rudists are reviewed and the results synthesized with evidence for climate change to yield an explanatory model. Extensive platform growth throughout the Atlantic/Tethys/low‐palaeolatitude Pacific seamount belt in the earliest Aptian was accompanied by prolific rudist diversification, especially among the predominantly aragonitic caprinids occupying platform margins. It was ubiquitously interrupted in the mid‐Early Aptian, in tandem with major perturbations of the global carbon cycle that culminated in Oceanic Anoxic Event 1a, although the causal linkages remain contentious. Platform growth terminated along most of the northern Tethyan margin and maybe also in the New World. Meanwhile, Lithocodium/Bacinella or similar microbial encrustations became widespread in lower palaeolatitudes. Recovery of Tethyan platforms in the late Early Aptian was limited to lower palaeolatitudes. Caprinid‐rich platform margin facies again prevailed in central and southern Tethyan areas, but gave way to those dominated by rudists with a thickened calcitic outer shell layer (polyconitids and requieniids) in marly successions around Iberia. The end of the Early Aptian saw the Lazarus‐style disappearance of caprinids, and renewed Tethyan platform growth in the Late Aptian was dominated by calcite‐rich rudists, although rudists remained scarce in the New World until the terminal Aptian. This study postulates that sea water acidification influenced both the mid‐Early Aptian platform debacle and the subsequent late Early Aptian geographical restriction of platform recovery, although in contrasting atmospheric regimes. At first, it was forced by the increasing atmospheric levels of volcanically derived CO2, with mitigation in low latitudes from thermal expulsion of aqueous CO2 (here termed the ‘kettle effect’) due to greenhouse warming. However, subsequent cooling due to drawdown of atmospheric CO2 by organic carbon burial could have sustained acidification of platform waters in higher latitudes, by reducing the protective kettle effect there. Caprinid susceptibility to such assaults may have been as much due to exposure on their preferred outer platform habitats as to their mineralogy. The increased calcite/aragonite ratio among rudists through the Aptian resulted largely from this taxonomic turnover.