Miocene deep-water agglutinated Foraminifera from ODP Hole 909c: Implications for the paleoceanography of the Fram Strait Area, Greenland Sea

Deep-water agglutinated Foraminifera (DWAF) are investigated from Miocene sediments recovered from ODP Hole 909C in the Fram Strait, Norwegian-Green land Sea. We studied 125 samples from Cores 909C-50R to -103R. and recovered over 60 species of DWAF. The faunal succession in Hole 909C is subdivided into three assemblages based on the stratigraphic ranges of characteristic cosmopolitan taxa. These are: (1) a diverse Reticulophraginium amplectens - Reophanus berggreni Assemblage in Cores 909C-100R-2 to -91R-1 (1040.71-952.78mbsf); (2) a Reticulophragmium amplectens Assemblage in Cores 909C-87R-2, to -71R-3 (915.7-762.68mbsf); and (3) a low-diversity Reticulophraginium rotundidorsatum Assemblage in Cores 909C-71R-1 to -55R-1 (759.68-605.52mbsf). The DWAF assemblages are correlated to the standard chronostratigraphy using dinoflagellate cysts and magnetostratigraphy. The stratigraphic ranges of some well-known Palcogene DWAF species extend far into the Miocene at this locality, confirming tire hypothesis that the Arctic and northern Norwegian Sea basins served as a refuge for these species long after they disappeared from the North Atlantic stratigraphic record. The taxonomic affinities of the Miocene assemblages from Hole 909C supports the idea that an estuarine Circulation pattern has been in place between the Arctic Ocean and Greenland Sea basins since at least the early Miocene. Changes in the benthic foraminiferal morphogroups within the R. rotundidorsatum Assemblage correlate with an increase in total organic carbon, indicating an increase in oceanic productivity in the Fram Strait region during the late Miocene

Four new species of deep water agglutinated foraminifera from the Oligocene-Miocene of the Congo Fan (offshore Angola)

Four new species of deep-water agglutinated benthic foraminifera are described from the Oligocene and Miocene of the Congo Fan, offshore Angola. Scherochorella congoensis n.sp., Paratrochamminoides goroyskiformis n.sp., Haplophragmoides nauticus n.sp. and Portatrochammina profunda n.sp. all occur in deep-sea turbiditic shales and sands from the distal section of the Congo Fan

Calibration of the Benthic Foraminiferal Oxygen Index in the Marmara Sea

Benthic foraminifera (total assemblages) were studied from 30 sea-floor samples collected along a bathymetric transect on the southern shelf of the Marmara Sea from depths of 15–350 m. At each station, Kaiho’s Benthic Foraminiferal Oxygen Index (BFOI) was calculated based on species abundances using the methods outlined by Kaiho (1994). The calculated BFOI values were converted to analogue oxygen values, and calibrated to the dissolved oxygen values measured 1 m above the sea floor at each station. In the surface waters and central part of the Marmara Shelf transect, the BFOI values reproduce the measured dissolved oxygen values with a remarkable degree of accuracy. Beneath the pycnocline at depths of 30 to 75 m, the BFOI underestimated the measured oxygen values. This discrepancy is attributed to seasonally higher summer oxygen values within the chlorophyll maximum, corresponding to the position of the Mediterranean Inflow Water (MIW) present during summer. In the deeper part of the transect (below 140 m), BFOI values overestimated the measured oxygen values. This discrepancy is attributed to the presence of denser MIW that cascades down the submarine canyon beneath the Marmara ship channel during winter, ventilating the deep Marmara Sea. The BFOI accurately points out the seasonal differences in the position and depth of the MIW in the southwestern Marmara Sea. The BFOI likely reflects the longer-term oxygen values averaged over the span of many years

Karreriella perforata n. sp. : a new Pliocene agglutinated benthic foraminifer with a perforated wall structure from the southern Bering Sea

This is the final version of the article. Available from the Grzybowski Foundation via the link in this record.We describe a new agglutinated benthic foraminiferal species from the Pliocene of Hole U1341B drilled in the southern Bering Sea during IODP Expedition 323. The calcareous-cemented species Karreriella perforata n.sp. is coarsely canaliculated, with regularly-spaced straight, unbranched pores that are open to the test surface. This feature of the test wall is rare among agglutinated foraminifera, and is interpreted as a morphological adaptation to enable survival in the strongly hypoxic environment present in the deep Bering Sea.We are grateful for the support provided by King Abdulaziz City for Science and Technology (KACST) through the Science and Technology Unit at King Fahd University of Petroleum & Minerals (KFUPM) for partially funding this work under project No. 11-ENV1613-04 as part of the National Science, Technology, and Innovation Plan

Oligocene Deep-Water Agglutinated Foraminifera from the Congo Fan, Offshore Angola: Palaeoenvironments and Assemblage Distributions

Seventh International Workshop on Agglutinated Foraminifera, Urbino, Italy, October 2-8, 2005Agglutinated foraminiferal assemblages from the Oligocene section of an exploration well drilled in the distal part of the Congo Fan are fully documented and interpreted for palaeoenvironment. A total of 65 ditch cutting samples were analysed at 10 m intervals, from 3630 to 4270 m below rotary table. An average of 170 specimens were extracted per sample, with over 100 species being documented and described using SEM and light photography. The results reveal the most taxonomically diverse deepsea Oligocene fauna yet described. Six assemblages have been defined and analysed with Correspondence and 'Morphogroup' Analysis. These are 1. Nothia robusta / Reticulophragmium Assemblage (4110-4270 m), 2. Nothia robusta / Scherochorella congoensis / Discamminoides sp. 1 Assemblage (4000-4100 m), 3. High diversity Reticulophragmium Assemblage (3870-3990 m), 4. Portatrochammina profunda Assemblage (3790-3860 m), 5. Nothia latissima Assemblage (3730-3780 m) and 6. Low abundance Assemblage (3630-3720 m). Palaeobathymetric estimates range from middle - lower bathyal based on comparison with living taxa and morphogroup distributions. These results extend the known stratigraphic range (last occurrences) of Reticulophragmium amplectens into the Oligocene in the Atlantic, and possibly also Paratrochamminoides gorayskii, Paratrochamminoides olszewskii, Trochamminoides aff. proteus, Trochamminoides subcoronatus, Haplophragmoides horridus and Haplophragmoides walteri, although reworking is documented with these species. Results also extend the known first occurrences of Recurvoides azuaensis, Spiropsammina primula, Cyclammina aff. orbicularis, Discamminoides sp. and Glaphyrammina americana into the Oligocene. Large scale variations within faunas are largely assigned to documented variations in sand content, where higher proportions of sand generally coincide with reduced diversity and abundance along with a dominance of opportunistic species such as Nothia robusta, Nothia latissima and Ammodiscus latus. A major excursion in the infaunal morphogroup, suspension-feeding morphogroup and diversity and abundance within Assemblage 2 is termed the 'Scherochorella Event', and does not correlate with an increase in sand. This fauna is thought to be the result of lower oxygen conditions allowing the dominance of the low oxygen morphotype Scherochorella congoensis and the opportunistic species Nothia robusta. Deep-water circulation in the Atlantic at this time is generally thought to have been strong, and this event suggests that there may have been a temporary expansion of the oxygen minimum zone during the Late Oligocene, coinciding with increased benthic δ18O values, global cooling, and increased upwelling associated with a stronger polar front. The otherwise high diversity of the fauna in the well supports the interpretation of well-oxygenated conditions.We would like to thank BP Exploration for their support in fully funding this project

Foraminifera from the Eocene variegated shales near Barwinek (Magura unit, Outer Carpathians), the type locality of Noth (1912) revisited

This is the final version of the article. Available from the Polish Geological Society via the URL in this record.A rich deep-water agglutinated foraminifera (DWAF) fauna (approximately 50 taxa) is documented from the lower to middle Eocene Variegated Shales of the Magura Unit, Outer Carpathians. Four localities have been sampled from the Barwinek region, which are thought to correspond to those studied by Rudolf Noth in 1912. A stream section of variegated red and green shales outcrop near Zyndranowa (Poland), was logged and extensively sampled. A further two outcrops of red shales were sampled in stream sections near Vyšny Komarnik (Slovakia), and a stream section close to Olchowiec (Poland). The DWAF recovered closely resemble assemblages of the same age in localities throughout the Carpathians. The material under study in this report has been correlated using the first appearance of Reticulophragmium amplectens, dating the samples early Middle Eocene. Two DWAF assemblages have been differentiated. The 'Rhabdammina Assemblage' is found mainly in green shales and is thought to be indicative of a high-energy slope or deep sea fan environment slightly reduced in oxygen; and the 'Paratrochamminoides Assemblage' is found mainly in red shales and is thought to be indicative of a well-oxygenated condensed sequence. The two faunas are otherwise very similar in composition. Of the seven new species described by Noth in 1912, one has been identified in this report and re-described as Paratrochamminoides deflexiformis (Noth).This study was originally carried out as an MSc project in Micropalaeontology at U.C.L. We would like to thank AAPG student Grants-in-Aid programme and the EEC-Socrates programme for the essential funding provided in support of this projec

pi^0 pi^0 Scattering Amplitudes and Phase Shifts Obtained by the pi^- P Charge Exchange Process

The results of the analysis of the pi^0 pi^0 scattering amplitudes obtained with pi^- P charge exchange reaction, pi^- P --> pi^0 pi^0 n, data at 9 GeV/c are presented. The pi^0 pi^0 scattering amplitudes show clear f_0(1370) and f_2(1270) signals in the S and D waves, respectively. The pi^0 pi^0 scattering phase shifts have been obtained below Kbar K threshold and been analyzed by the Interfering Amplitude method with introduction of negative background phases. The results show a S wave resonance, sigma. Its Breit-Wigner parameters are in good agreement with those of our previous analysis on the pi^+ pi^- phase shift data.Comment: 4 pages, 4 figures. Proceedings of the int. conf. Hadron'99 at Beijing, Aug. 1999. Presented for the collaboration of A.M.Ma, K.Takamatsu, M.Y.Ishida, S.Ishida, T.Ishida, T. Tsuru and H. Shimizu, and the E135 collaboration. For our activities on sigma, visit http://amaterasu.kek.jp/sigm