Bolboforma from Leg 105, Labrador Sea and Baffin Bay, and the chronostratigraphy of Bolboforma in the North Atlantic

The genus Bolboforma, first described by Daniels and Spiegler (1974), is a problematic group of calcareous microfossils. Solbaforma is most probably a planktonic cyst (Rogl and Hochuli, 1976) having protozoan or algal affinities (Poag and Karowe, 1986). Its known distribution at present suggests that various species may have potential for becoming good stratigraphic indicators. Bolboforma also may be useful in areas where other calcareous planktonic microfossils are poorly preserved, i.e., the North Sea, the Norwegian-Greenland Sea, and Baffin Bay. This report summarizes the known occurrences of Bolboforma in the North Atlantic and correlates them with a standard geochronology (Berggren et al., 1985a, 1985b). In addition, further occurrences of Bolboforma are reported from Sites 645, 646, and 647 (Fig. 1)

Remarks on the type locality and current status of the foraminiferal species Rzehakina epigona (Rzehak, 1895)

A likely topotype locality is proposed for Rzehakina epigona. As the type specimen of Silicina epigona Rzehak, 1895 is assumed to be lost, we undertook a search for new material in the type area, Zdounky village in Moravia. A single locality provided a total of 138 Rzehakina specimens. The greenish grey marly clays sampled here contain a rich fauna of both planktonic and benthic foraminifers belonging to the Abathomphalus mayaroensis Zone. In addition to R. epigona, rare specimens attributable to R. inclusa, R. lata, R. minima and even a typical form of R. fissistomata are present at the Zdounky locality. Biometrical analysis was carried out on 52 complete specimens using the involution value "Z" and the length/breadth ratio. Most of the Rzehakina epigona topotypes form a tight cluster with "Z" values between 4 and 15%, although forms that appear transitional to R. lata have Z values of around 20%. The length/breadth ratio is more variable, with values ranging between 1.2 and 2.0. However, the Z value measured from Rzehak's type figure is significantly higher and outside the range of variability of this cluster of specimens. We conclude that Rzehak's drawing may be imprecise. Unfortunately, we were not able to study the inner structure of these specimens owing to the lack of internal filling in these specimens. The unfavourable preservation and low abundance of specimens from the type locality do not enable a proper revision of the species Rzehakina epigona at this time

Taxonomy and biostratigraphy of new and emended species of Cenozoic deep-water agglutinated foraminifera from the Labrador and North Seas

Deep marine, fine grained sedimentary strata of Maastrichtian through Miocene age in the Labrador and North Sea sedimentary basins are rich in agglutinated benthic foraminifera. Six new taxa have been found in these regions, several of which also extend to other circum-Atlantic Paleogene localities. The new taxa are: Ammomarginulina aubertae, n. sp. (Maastrichtian to Eocene), Adercotryma agterbergi, n. sp. (middle Eocene to lower Oligocene), Reticulophragmoides jarvisi (Thalmann) emended herein (Paleocene to lower Oligocene), Reticulophragmoides sp. 5 (Oligocene to Miocene), and Spiroplectammina navarroana Cushman emended herein (Maastrichtian to lower middle Eocene). The last occurrences of these taxa are important elements in the high-resolution probabilistic biozonations for the Labrador and North Sea basins

Rectoprotomarssonella n. gen., a new agglutinated foraminiferal genus from the Upper Cretaceous of the Carpathian Flysch

The new agglutinated foraminiferal genus Rectoprotomarssonella n. gen. is characterized by its high trochospiral coiling with multiserial to uniserial chamber arrangement and solid, noncanaliculate wall with calcareous cement. This taxon shows close relationship to the Cretaceous genus Protomarssonella Desai and Banner, from which it differs in possessing a uniserial part. The type species is a stratigraphic indicator in Campanian to Maastrichtian deep-water sediments in the Western Tethys and North Atlantic

Upper Cretaceous, K/T boundary, and Paleocene agglutinated foraminifers from Hole 959D (Côte d'Ivoire-Ghana Transform Margin)

Upper Cretaceous agglutinated foraminifer assemblages from Hole 959D of Ocean Drilling Program (ODP) Leg 159, Côte d’Ivoire-Ghana Transform Margin, reflect the subsidence history and paleoceanography of the widening equatorial Atlantic gateway. Five benthic foraminifer assemblage types are recognized: (1) Santonian and the lowermost Campanian assemblages (Cores 159-959D-65R and 64R) are characterized by the occurrence of bathyal calcareous benthic foraminifers with an increasing proportion of agglutinated foraminifers. The disappearance of calcareous foraminifers and assemblages exclusively composed of organically cemented agglutinated forms in Section 159-959D-65R-3 reflects the subsidence of the seafloor below the calcite compensation depth (CCD); (2) lower Campanian "biofacies B" assemblages (Cores 159-959D-63R through 61R) are exclusively composed of low-diversity agglutinated foraminifers, accompanied by abundant and occasionally well-preserved radiolarian assemblages; (3) middle Campanian to upper Maastrichtian deposits (Cores 159-959D-59R through 49R) contain an exclusively agglutinated Rzehakina epigona biofacies, which is well-known from middle to deep bathyal sites along the North Atlantic margins; (4) a change in agglutinated foraminifer assemblage composition toward morphologies commonly observed in present infaunal habitats and the common occurrence of the presumably infaunal genus Spiroplectammina are observed in Core 159-959D-48R. This change in agglutinated foraminifer assemblages corresponds to the Tethyan early Paleocene "Spiroplectammina event;" (5) a diversified Paleocene "Lizard Springs type" assemblage is characterized by several diverse Rzehakina, Saccamina, and Haplophragmoides species. Assemblages from Cores 159-959D-48R through 44R display high species diversity and reflect the deepest (lower bathyal to upper abyssal) paleobathymetry. Ranges of agglutinated foraminifer marker species and occurrences of paleoceanographic events within this biostratigraphic framework are almost identical to those observed in the North Atlantic, in the Western Tethys, and along the conjugate Brazilian margin. These observations lead us to confirm that a deep-water circulation system common to the North and South Atlantic has been active at least since the Santonian

Aluminium oxide in the optical spectrum of VY Canis Majoris

We report the first identification of the optical bands of the B-X system of AlO in the red supergiant VY CMa. In addition to TiO, VO, ScO, and YO, which were recognized in the optical spectrum of the star long time ago, AlO is another refractory molecule which displays strong emission bands in this peculiar star. Simulating the bands of AlO, we derive a rotational temperature of the circumstellar gas of Trot=700K. By resolving individual rotational components of the bands, we derive the kinematical characteristics of the gas, finding that the emission is centered at the stellar radial velocity and its intrinsic width is 13.5 km/s (full width at half maximum). It is the narrowest emission among all (thermal) features observed in VY CMa so far. The temperature and line widths suggest that the emission arises in gas located within ~20 stellar radii, where the outflow is still being accelerated. This result contradicts equilibrium-chemistry models which predict substantial AlO abundances only to within a few stellar radii. We argue that non-equilibrium models involving propagation of shocks are needed to explain the observations.Comment: to appear in A&

Determination of the Io heat flow. 1: Eclipse observations

The thermal emission from Io during eclipse by Jupiter yields data from which the total thermal flux from the volcanoes on the satellite surface can be estimated. Thermal infrared observations in spectral bands between 3.5 and 30 microns of five Io eclipse reappearances and one eclipse disappearance are reported and discussed. The thermal emission of the volcanoes which occurs almost all of the time was determined from the Io heat flux data. The thermal observations of Io are discussed with respect to previous thermophysical theories

Early to middle Miocene foraminifera from the deep-sea Congo Fan, offshore Angola

Analysis of a 630m section of an exploration well penetrating the distal part of the Congo Fan (~2000m water depth) yielded high abundance and diversity assemblages of agglutinated and calcareous benthic foraminifera. Planktonic foraminifera constrain the age to Early – Middle Miocene, and \delta 18O records reveal the Mi1 (~16.3 Ma) isotopic shift. Relatively few taxonomic studies of deep-water calcareous and agglutinated benthic foraminifera exist from this time period in this locality. All species encountered are therefore taxonomically described and documented using SEM photography (over 170 species), along with 27 species of planktonic foraminifera. Faunas show close affinities to those of the eastern Venezuela Basin, Gulf of Mexico and Central Paratethys. Seven assemblages are defined and analysed using morphogroup analysis and Correspondence Analysis, documenting the response of benthic foraminifera to three primary environmental-forcing factors; energy levels in the benthic boundary layer, oxygen levels relating to changing surface water productivity, and fluctuations in the level of the CCD. Near the top and bottom of the studied section both foraminiferal abundance and diversity decrease, corresponding with increased sand content implying greater energy levels and environmental disturbance. The majority of the section consists of shales with very low percentage sand, high foraminiferal abundance and diversity, and high sedimentation rates of ~10cm/kyr. Morphogroup analysis reveals a major switch in the fauna at around oxygen isotope event Mi1, with the transition from an epifaunal-dominated Cibicidoides assemblage to shallow infaunal-dominated Bulimina assemblage. We regard this as likely due to expansion of the oxygen minimum zone (paleobathymetric estimates are ~1000m) related to increased surface-water productivity and global cooling. Shifts in calcareous foraminiferal percentage over the studied interval overprint these signals and are believed to be related to a shoaling CCD, linked to reduced oceanic acidity and global atmospheric CO2 levels during the early Middle Miocene Monterey Carbon Isotope Excursion