The Late Cretaceous–Early Paleocene palaeobathymetric trends in the southwestern Barents Sea — Palaeoenvironmental implications of benthic foraminiferal assemblage analysis

2011 ◽  
Vol 307 (1-4) ◽  
pp. 44-58 ◽  
Author(s):  
Eiichi Setoyama ◽  
Michael A. Kaminski ◽  
Jarosław Tyszka
2019 ◽  
Vol 138 (1) ◽  
pp. 1-15
Author(s):  
Luca Samperi ◽  
Kamaldeen Omosanya ◽  
Giorgio Minelli ◽  
Ståle Johansen

2021 ◽  
Author(s):  
Erik Wolfgring ◽  
Michael A. Kaminski ◽  
Anna Waśkowska ◽  
Maria Rose Petrizzo ◽  
Eun Young Lee ◽  
...  

<p>Site U1512 was drilled during Expedition 369 of the International Ocean Discovery Program (IODP), which is located in the Great Australian Bight, southern Indian Ocean. It provides exceptional insights into the benthic foraminiferal biostratigraphy and paleoecology of a high southern latitude restricted marginal marine basin during the Late Cretaceous hot greenhouse climate and the rifting between Australia and Antarctica. The sedimentary sequence recovered at Site U1512 presents a rare record of a deep water agglutinated foraminifera (DWAF) community from the Southern High Latitudes. The Cretaceous record at Site U1512 covers the lower Turonian through Santonian (nannofossil zones UC8b to UC12/CC10b to CC16, <em>H. helvetica</em> to <em>Marginotruncana</em> spp. - <em>Planoheterohelix papula</em> - <em>Globotruncana linneana</em> planktonic foraminifera zones). Diverse benthic foraminiferal assemblages yield many new taxa that are yet to be described.</p><p>Agglutinated forms dominate the assemblage in most intervals. In lower to mid Turonian and Santonian strata, calcareous benthic as well as planktonic foraminifera are frequent. Abundant radiolaria are recovered from the mid Turonian, and they increase up-section and exceed 50% of the microfossil assemblage. We documented a diverse benthic foraminiferal assemblage consisting of 162 taxa (110 agglutinated and 52 calcareous). The most common taxa of the DWAF assemblage are tubular (i.e., <em>Kalamopsis grzybowskii,</em> <em>Bathysiphon</em> spp.) and planispiral forms (i.e., <em>Ammodiscus</em> spp., <em>Haplophragmoides</em> spp., <em>Buzasina</em> sp., <em>Labrospira</em> spp.).</p><p>The Turonian strata yield highly abundant <em>Bulbobaculites problematicus</em> and <em>Spiroplectammina navarroana</em>. The presence of the agglutinated foraminiferal marker taxa <em>Uvigerinammina jankoi</em> and <em>Bulbobaculites problematicus</em> provides a tie-point to the Tethyan DWAF biozonation of Geroch and Nowak (1984). The composition of foraminiferal assemblages and the increase in radiolaria abundance suggest unstable environmental conditions at Site U1512 during the early Turonian through Santonian. These characteristics refer to changes in bathymetry associated with changing ocean chemistry. Results of quantitative analyses of the benthic foraminiferal assemblages indicate a restricted paleoenvironmental regime, dictated by changes in paleobathymetry, unstable patterns in ocean circulation, and the discharge of a nearby river delta system.</p><p>References: Geroch, S., Nowak, K., 1984. Proposal of zonation for the Late Tithonian – late Eocene. based upon arenaceous Foraminifera from the Outer Carpathians, Poland, 225-239, In: Oertli, H.J. (Ed.), Benthos ´83; 2nd international 915 Symposium on Benthic Foraminifera, Pau (France) April 11-15, 1983, Elf Aquitaine, ESO REP and TOTAL CFP, Pau and Bordeaux.</p><p> </p>


2018 ◽  
Vol 48 (1) ◽  
pp. 17-28 ◽  
Author(s):  
Safia Al Menoufy ◽  
Mohamed Boukhary

Abstract Nummulites fayumensis n. sp. and Nummulites tenuissimus n. sp. are described from the Munqar El-Rayan Section, Fayum, Egypt. Nummulites tenuissimus belongs to the N. partschi group, while N. fayumensis belongs to the N. gizehensis group, based on diameter and protoconch sizes, septal shape and granulations. Both new species are of Lutetian age, assigned to SBZ14/15, and encountered in shallow-marine facies. Wadi El-Rayan is an important site for vertebrate fossils in Egypt and the abundant larger benthic foraminiferal assemblage provides insight into paleoenvironmental parameters associated with the deposition of Eocene-age rock units of the Munqar El-Rayan Section.


2018 ◽  
Vol 130 (7-8) ◽  
pp. 1143-1163 ◽  
Author(s):  
Caitlin E. Leslie ◽  
Daniel J. Peppe ◽  
Thomas E. Williamson ◽  
Matthew Heizler ◽  
Mike Jackson ◽  
...  

2011 ◽  
Vol 30 (2) ◽  
pp. 119-128 ◽  
Author(s):  
Oliver Friedrich ◽  
Silke Voigt ◽  
Tanja Kuhnt ◽  
Mirjam C. Koch

Abstract. Published proxy data for Oceanic Anoxic Event 2 (OAE 2 or Cenomanian–Turonian Boundary Event) and other mid-Cretaceous OAEs indicate widespread anoxic bottom-water conditions. However, increasing evidence shows that anoxia was not permanent but subject to significant fluctuations. We have generated X-ray fluorescence elemental concentration and benthic foraminiferal assemblage records for a short section of OAE 2 black shales from Wunstorf, northern Germany. Two intervals of low sulphur elemental concentration are interpreted as periods of increased oxygenation of bottom waters. This is supported by benthic foraminiferal assemblage data showing repopulation events associated with these intervals. These repopulation events are characterized mainly by the occurrence of agglutinated taxa, with Lingulogavelinella globosa being the only abundant calcareous species. This observation is interpreted in terms of short-term interruptions of the otherwise anoxic bottom-water environment. Comparison with repopulation events during OAE 1b and Quaternary sapropels make it reasonable to speculate that short-term cooling and an associated increase in bottom-water ventilation at the NW European shelf sea are the main trigger mechanisms for the observed repopulation events at Wunstorf. As source area for benthic foraminifera, shallower parts of the Lower Saxony basin are proposed.


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