ALBERT

Description: Samples from 12 wells situated mainly in the northern part of the Cyrenaica Shelf of northeast Libya have yielded palynomorph assemblages of Aptian, Albian or Cenomanian aspect. The Aptian assemblages are dominated by land-plant remains and contain relatively few dinoflagellate cysts. By contrast, the latter are generally common in those from the Albian and Cenomanian samples. Deposition in near-shore marine environments is indicated for most of the Aptian succession whereas more open marine conditions are generally suggested for the younger strata. In places, however, a substantial terrestrial input was maintained during the accumulation of the Albian sediments.Dinoflagellate cysts typically recorded from Aptian palynological preparations include Aptea anaphrissa, Cyclonephelium sp. 1, Hystrichosphaerina schindewolfii, Muderongia simplex microperforata and Occisucysta spp. Several species of Cribroperidinium, but especially C. edwardsii and C. orthoceras, usually form an important part of the Albian assemblages; Kiokansium hydra is also often present. Skolochorate cysts referable to Coronifera and Florentinia are abundant in both these and the Cenomanian preparations, with Palaeohystrichophora infusorioides and several species of Canningia, Cyclonephelium, Oligosphaeridium, Spiniferites and Subtilisphaera being among the most numerous of the associated forms. In general the assemblages compare closely with those of similar age described by Below (1981, 1982) and Williams (1978) from onshore and offshore Morocco respectively.Although miospores are common in the Aptian preparations, they show relatively little morphological diversity. Smooth walled triradiate specimens, Classopollis and Inaperturopollenites are often the dominant forms. Angiosperm pollen grains are generally scarce and bisaccates only rarely encountered. A few of the Albian . . .

Description: The data obtained from an independent study of acritarchs, chitinozoans and miospores enables the determination of maximum age ranges of samples taken from three wells. These are shown in Fig. 8.ACRITARCHSAt present, samples have been examined from six wells – A1-46, Core 2; E1-81, Cores 3, 4; F1-46, Core 3; D-31, Core 1; A1-81, Core 3 and C1-31, Core 8. The last mentioned is considered no further here as all samples have to date proved barren. The oldest of the acritarch assemblages are recorded from E1-81, Cores 3, 4 between 1850ft. and 2340ft. (Fig. 8) and from A1-81, Core 3 between 3750ft. and 3773 ft. These are dominated by the polygonomorph acritarchs, Veryhachium trispinosum and V. valiente but also include acanthomorphs such as Diexallophasis and Multiplicisphaeridium. The lack of diagnostic acritarchs of post convolutus zone would indicate the age of the samples as Rhuddanian to Early Aeronian but no higher than convolutus zone. Wells A1-46, Core 2 between 9710 to 9721 ft. (Fig. 8); D1-31, Core 1, 6105 to 6160ft. (Fig. 8) and F1-46, Core 3, 8852 to 8858 ft. all yield rich assemblages dominated by Multiplicisphaeridium, Diexallophasis and Veryhachium and characteristic species of Visbysphaera, Cymbosphaeridium, Oppilatala and ?Dateriocradus. The presence of forms such as Oppilatala eoplanktonica, ?Dateriocradus monterrosae, Multiplicisphaeridium arbusculiferum, Diexallophasis caperoradiola and Visbysphaera gotlandicum indicate the assemblages are of post-convolutus zone age, thus late Aeronian, as an oldest date.Regional palynological differences in the acritarch assemblages are observed between North Africa and Great Britain, which are consistent . . .

Description: Living coccolithophore assemblages were investigated in 35 surface water samples taken from the Natal Valley (southwest Indian Ocean) in January and November, 1983 and February, 1984. Fifty-nine species were recognised using a scanning electron microscope (S.E.M.). Cluster analysis revealed four different species assemblages dominated by Emiliania huxleyi, Umbilicosphaera hulburtiana, Umbellosphaera tenuis and Gephyrocapsa oceanica. Significant differences in species composition between the sampling periods are attributed to seasonal fluctuations. The regional distribution of the assemblages reflects two different océanographic regimes: 1) The Agulhas Current, which is a nearly stable feature and 2) the area of the Agulhas Return Current, characterised by rapidly changing hydrographic and ecological conditions.

Description: Several species of Mesozoic megaspores that are sculptured with globular, often gemmate elements are sufficiently distinct from most verrucate forms to warrant their inclusion in a genus other than Verrutriletes. Cabochonicus is erected to accommodate them with C. (al. Verrutriletes) carbunculus as the type species. The form of the gemmae, which have a glossy appearance, has been the subject of past debate with one interpretation being that they are the manifestation of fungal attack rather than sculpture. Evidence from ultrastructural studies suggests, however, that they are exinal excrescences. The spores are assumed to be the products of heterosporous lycopods and the structure of the wall layers may indicate selaginellalean affinities. The plants are more likely to have been terrestrial than aquatic or semi-aquatic.

Description: Provisional registration numbers allocated to some type specimens of ostracods described by G. S. Brady from the SW Pacific are replaced with Hancock Museum Registration Numbers.

Description: Macrofaunal and foraminiferal analyses have shown the Woodbine Shale in South Cumbria to be of latest early Asbian age. Ostracods and solid foraminifera from the Woodbine Shale are described and illustrated for the first time. Several ostracods including Rectobairdia cf. dorssenata, Healdia ‘penchfordensis’, Bairdia cf. leguminoides, Pustulobairdia cf. confragosa and Microcheilinella subcorbulinoides, previously only known from late Asbian or younger strata, have now been shown to range into the early Asbian. The numerous bairdiids, heavily ornamented ostracods, trilobites, brachiopods and abundant foraminifera suggest a deep, subtidal, marine environment of deposition for the Woodbine Shale. Foraminifera from the underlying Lower Urswick Limestone suggest an early Asbian age for this formation whilst the overlying Upper Urswick Limestone is shown to be of late Asbian age. The foraminiferal assemblages from these beds can be correlated directly with those in the early Asbian Upper Potts Beck Limestone and the late Asbian Knipe Scar Limestone in the Asbian stratotype section at Little Asby Scar, Cumbria.

Description: The cyst-theca relationship of Protoperidinium americanum (Gran & Braarud) Balech was investigated using single cyst germination techniques. This Protoperidinium has an unusual theca with four intercalary plates (plate formula 4’, 4a, 7″, 4c, 7s, 5″’, 2″″). It has a distinctive brown capsulate cyst which has an apical archeopyle. The position of this species in the genus Protoperidinium is discussed. The distribution of the cyst on the west coast of Scotland is described.

Description: Striate tricolpate pollen has been recovered from Early Cretaceous samples of the borehole Mersa Matruh 1 in the N.W. Desert of Egypt. Scanning Electron Microscope (SEM) study has revealed fine details of their exine scupture, on the basis of which four new taxa, STRIOTRI-OVAL, STRIOTRI-SMOOTHMUR, STRIOTRI-SEGMUR and STRIORET-SMOOTH, are distinguished. The stratigraphic ranges of these are discussed and they are compared with other published species. They are among the oldest striate tricolpate pollen yet described, appearing in sediments of Early Aptian age, slightly predating the first reliable records of reticulate tricolpates in the sequence studied. The lack of earlier reticulate grains is attributed to possible sample failure. There is evidence that the true first appearance of tricoplate pollen in Egypt may be late Barrenian.

Description: Relative frequencies of heterohelicid species in the Maastrichtian of DSDP Site 605, DSDP Hole 111A and Imperial Oil/Amoco core hole C23 on the Grand Banks have been estimated to show temporal and geographic variation patterns in terms of Cretaceous faunal provinces. Heterohelix globulosa and H. planata dominate the shallow marine heterohelicid faunas of core hole C23. Together with H. dentata and H. glabrans they are the most common forms in the temperate faunas from Hole 111A. Pseudoguembelina spp are common in the Tethyan faunas from Site 605 but are rare in Hole 111A. Racemiguembelina spp and fully developed Pseudotextularia spp exclusively occur at Site 605. A distinct but unexplained faunal boundary within the Site 605 section involves frequency shifts of three “relatively cold” species. H. dentata, H. glabrans and H. planata. Dissolution effects, expressed in changes in the relative frequencies of H. globulosa and Pseudotextularia elegans, are present in several intervals across the section. H. globulosa is the most sensitive for dissolution. Pst. elegans is resistant, as are to a lesser extent, Gublerina cuvillieri, Pseudoguembelina excolata, Psg. palpebra, and Planoglobulina acervulinoides.

Description: The Marls of Merbah el Oussif are part of the Permian series of the Jebel Tebaga of Médénine in Tunisia. They belong to the uppermost Murghabian, a stage intermediate between the Wordian and the Capitanian. These green marls were deposited in lows at the base of sponge bioherms. The sedimentation rate was high and the environment well oxygenated. The marls contain a relatively rich assemblage of isolated sponges, gastropods, smaller foraminifera, fusulinids, dasycladacean algae and ostracods. Amongst those, for the first time reported from the Permian of Tunisia, 14 species have been identified and one new species described, Bairdiacypris postrectiformis sp. nov. The geographic and stratigraphic distribution of several species are discussed. This ostracod fauna indicates a shallow nearshore environment and suggests a western, not eastern connection between the Tethys and the Texas Sea.