Palynology is the main method of correlating the subsurface glaciogenic Al Khlata Formation of Oman, due to extreme lateral variability of facies, and poor seismic resolution. The chief 2 operating company in Oman, Petroleum Development Oman, has developed a robust in-house palynozonation through almost 40 years of exploration and production based on thousands of samples and hundreds of well sections. In this paper the formal definitions of the biozones are published, and the biozones are correlated in detail with faunally-calibrated palynological biozones in Western Australia, thereby allowing correlation with the standard Russian stages.Seven biozones are distinguished. The oldest, biozones 2159A and B, of probable late Pennsylvanian age, are characterised by low diversity assemblages of Punctatisporites and monosaccate pollen, with Biozone 2159A having a lower proportion of monosaccate pollen than Biozone 2159B. Biozone 2165A, of probable Asselian age, is characterised by common cingulicamerate spores and Microbaculispora Group; while Biozone 2165B contains in addition to the above, common Horriditriletes Group, and is likely to be Asselian-Sakmarian in age. Biozone 2141A is characterised by common taeniate and non-taeniate bisaccate pollen and Cycadopites cymbatus, particularly toward the top; and the succeeding 2141B by

A thick succession of Al Khlata glacio-lacustrine deposits, including diamictites, crops out in the Wadi Daiqa inlier and there are other possible Al Khlata outcrops in Wadi Amdeh and Wadi al Arabiyin. These outcrops in the Oman Mountains are 100 km north of where the Al Khlata had been thought to pinch out by non-deposition or erosion. Fossil spores and pollen from Wadi Daiqa are highly carbonized having been subject to greenschist facies metamorphism, but are still clearly identifiable as taxa from the Late Carboniferous 2159A zone of the oil-producing areas of interior Oman. This northernmost Al Khlata is sand rich and interpreted to be glacio-lacustrine. Previously the sand-dominated Al Khlata successions north of the Central Oman High have been considered to be glacio-fluvial outwash largely based on their context. The Al Khlata deposits in Wadi Daiqa and the underlying several-kilometre-thick Amdeh succession are preserved in Saih Hatat, probably in a continuation of the Ghaba Salt Basin that itself overlies an accreted terrane from the Pan African orogeny.

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Palynology is the main method of correlating the subsurface glaciogenic Al Khlata Formation of Oman, due to extreme lateral variability of facies, and poor seismic resolution. The chief 2 operating company in Oman, Petroleum Development Oman, has developed a robust in-house palynozonation through almost 40 years of exploration and production based on thousands of samples and hundreds of well sections. In this paper the formal definitions of the biozones are published, and the biozones are correlated in detail with faunally-calibrated palynological biozones in Western Australia, thereby allowing correlation with the standard Russian stages.Seven biozones are distinguished. The oldest, biozones 2159A and B, of probable late Pennsylvanian age, are characterised by low diversity assemblages of Punctatisporites and monosaccate pollen, with Biozone 2159A having a lower proportion of monosaccate pollen than Biozone 2159B. Biozone 2165A, of probable Asselian age, is characterised by common cingulicamerate spores and Microbaculispora Group; while Biozone 2165B contains in addition to the above, common Horriditriletes Group, and is likely to be Asselian-Sakmarian in age. Biozone 2141A is characterised by common taeniate and non-taeniate bisaccate pollen and Cycadopites cymbatus, particularly toward the top; and the succeeding 2141B by

The siliciclastic Haima Supergroup (Cambrian-Silurian) on the west flank of Al Ghabah Salt Basin in Oman is currently a target for gas exploration following the discovery of significant gas reserves. An understanding of stratigraphical and facies relationships within the Haima is crucial for their exploration and exploitation, and biostratigraphy is one of the more powerful and cost-effective tools that can be deployed to aid such understanding. The biostratigraphy of the Haima Supergroup is based primarily on palynomorphs. The pre-existing biozonation, comprising conventional interval zones, is of low resolution and incorporates misconceptions over the ranges of key species. The work reported here explicitly considered the biostratigraphy of the Haima Supergroup in the context of genetic sequence stratigraphy. It shows that each of the postulated marine-flooding events in the Haima Supergroup is characterised by a unique assemblage of marine palynomorphs. Intervening strata are characterised by low-diversity and sometimes sparse marine palynomorph assemblages, often comprising only sphaeromorph acritarchs, accompanied by terrestrial cryptospores. These low-diversity assemblages indicate proximal-marine to non-marine conditions, consistent with progradation following each marine flood. The sandy prograding deposits in the Haima Supergroup form reservoirs, which are sealed by the shales and mudstones deposited by succeeding marine-flooding events. Lateral changes in marine assemblages indicate onshore-offshore relationships, and have contributed towards mapping the extent of each marine-flooding event, critical for evaluation of the potential areal extent of seals. The result is improved biostratigraphical resolution, which enables more precise correlation between wells, and which has contributed to more detailed palaeogeographical maps and to a better assessment of the distribution of reservoir-seal pairs.