Conference PaperPDF Available

Quaternary palaeoceanography of the Atlantic

August 1984

Conference: 27th International Geological Congrass
At: Moscow
Volume: 3

Project: The stratigraphy of Quaternary ocean sediments and paleoceanology

Authors:

Max Semenovich Barash

P.P. Shirshov Institute of Oceanology

The method of foraminifers analysis in the combination with other methods of the research of oceanic sediments permits reconstructions of main features of the complex Quaternary paleoceanography in the Atlantic. The Quaternary climatic regime fluctuations of the Earth and, in particular, in the Atlantic, obviously resulted from the fluctuations of the astronomical factors. Cores of oceanic sediments verify that the astronomical fluctuations of the insolation were really manifested in climatic fluctuations. The spectra estimated by the oxygen-isotope curves for planktonic and benthic foraminifera tests, by variations in the ratio of radiolaria and foraminifera spe¬cies, by CaCO3 concentration, and by summer and winter temperature curves reconstructed from planktonic foraminifera also show maxima for periods of 19, 23, 41 and 100 th.y. Climatic and paleotemperature fluctuations in different parts of the Atlantic are discussed.

Content uploaded by Max Semenovich Barash

Content may be subject to copyright.

ResearchGate has not been able to resolve any citations for this publication.

ResearchGate has not been able to resolve any references for this publication.

Project

Influence of abiotic factors on the evolution of marine biota during the Phanerozoic

Max Semenovich Barash

Project

The stratigraphy of Quaternary ocean sediments and paleoceanology

Biostratigraphic subdivision and definition of the Quaternary age of ocean and marine sediments using micropaleontological and other methods. Reconstruction of paleo environment conditions (paleote mperatures, currents, hydrological fronts, distribution of ice, etc..). Correlation. Paleoclimatic reconstructions. Extrapolation of methods to earlier stratigraphic intervals and the corresponding constructions. ... [more]

Project

Stratigraphy of Tertiary deposits, paleooceanology, the formation of manganese and phosphorite nodules

Research of Tertiary sediments of the oceans and seas, their stratigraphy, reconstruction of paleooceanological conditions. The study of the processes of manganese and phosphorite nodules formation

Project

Marine Geology

Max Semenovich Barash

Article

Full-text available

Quaternary climatic changes indicated by planktic foraminifera of Northern Indian Ocean

June 1993 · Current Science

Arun Deo Singh

The relative abundances of planktonic foraminifera, the changes in their coiling and the isotopic record from deep sea cores of some crucial sites in Northern Indian Ocean indicate climatic fluctuations for the past 3.0 million years (Late Pliocene to Pleistocene). The abundance of temperate forms like Globigerina spp. together with sporadic occurrence of a polar species Neogloboquadrina ... [Show full abstract] pachyderma during specific time intervals suggest cooling episodes. Warmer intervals are marked by the dominance of tropical assemblages including Globigerinoides spp., Globorotalia s.l., Pulleniatina and Globoquadrina. On the basis of the planktonic foraminiferal frequency changes, four intervals of major climatic cooling have been recognized-one in the Late Pliocene (2-3 m.y.), three in the Pleistocene immediately above the Pliocene/Pleistocene boundary (1.6 m.y.), at 0.6 m.y., and during the late Pleistocene. Marked shift in coiling directions within Pulleniatina populations and Globorotalia s.l. is observed to coincide with the frequency changes. There was marked increase of δ l8O values in oxygen isotopic record of foraminiferal tests around 2-3 m.y. (Late Pliocene) and within the Pleistocene. Major faunal turnover accompanied by changes in coiling synchronous with the isotopic shifts, suggest these faunal changes to be climatically induced.

Article

Full-text available

Exploring the paleoceanographic changes registered by planktonic foraminifera across the Cenomanian-...

August 2021 · Global and Planetary Change

Planktonic foraminiferal population dynamics and benthic foraminiferal and radiolaria distributions combined with δ¹³C and δ¹⁸O measurements of both bulk carbonate and foraminifera provide clues concerning the paleoceanographic changes across the Cenomanian-Turonian boundary interval and the Oceanic Anoxic Event 2 (OAE 2) at southern high latitudes. Samples analyzed are from Integrated Ocean ... [Show full abstract] Discovery Program (IODP) Expedition 369 Site U1516 in the Mentelle Basin (eastern flank of the Naturaliste Plateau, Indian Ocean, SW Australia). Site U1516 was located at 60°–62°S paleolatitude during the mid-Cretaceous, and it is the first high latitude locality in the Southern Hemisphere where planktonic foraminifera are consistently recorded across the OAE 2 interval and its associated positive δ¹³C excursion. The sedimentary record at Site U1516 consists of a sequence of alternating black, dark greenish gray, and light greenish gray claystone in the Cenomanian that grade to white and light gray calcareous chalk interbedded with chert in the Turonian. The correlation between the δ¹³C and δ¹⁸O profiles at Site U1516 and the European reference section at Eastbourne (England) coupled with the integrated calcareous plankton biostratigraphy and stable isotopic data at Site U1516, indicate that a complete record of OAE 2 at Site U1516 was recovered. Below and in the lower part of OAE 2, the planktonic foraminiferal assemblages are dominated by small-sized (125–38 μm) opportunistic species of Microhedbergella and radiolaria indicating a dominantly eutrophic regime. Above the onset of OAE 2, a trough in the δ¹³C profile (Plenus Carbon Isotope Event: P-CIE) coinciding with a δ¹⁸O increase may correspond to the Plenus Cold Event as observed at low latitudes, although no evidence of cooling is registered in the microfossil assemblages. At Site U1516, the middle part of OAE 2 at the initiation of the plateau phase of the δ¹³C profile is masked by absence of carbonate, by the highest TOC values, and high biogenic silica (dominance of radiolaria) indicating this interval corresponded to a time of highly stressed eutrophic conditions with possible shoaling of the Carbonate Compensation Depth (CCD). Above this interval, bulk isotopic results yield lower δ¹³C values, and the CaCO3 increases are associated with the presence of even smaller-sized Microhedbergella showing cyclic fluctuations in absolute abundances with benthic foraminifera indicating dominantly eutrophic conditions likely affected by upwelling of nutrient-rich and δ¹³C-depleted intermediate water masses. Toward the top of OAE 2 and across the Cenomanian-Turonian boundary interval, the planktonic foraminiferal assemblages show changes in composition (e.g., Microhedbergella is replaced by Muricohedbergella), species occupying relatively deep ecological niches appear and an overall increase in diversity is observed. These features coupled with the foraminiferal species-specific δ¹³C and δ¹⁸O patterns reveal that Site U1516 occupied a paleoceanographic setting still affected by eutrophy likely related to enhanced input of nutrients but with episodes of stability with ecological/thermal separation in the surface waters. This interval also records the highest sea surface water paleotemperatures values estimated as 20°–23°C based on δ¹⁸O values of foraminiferal test and assuming seawater δ¹⁸O values of −1‰V-SMOW. Mesotrophic to oligotrophic conditions persisted after the OAE 2 and throughout the Turonian as evidenced by a diverse planktonic foraminiferal assemblage with different species occupying separate ecological niches in the mixed layer and thermocline.

Chapter

Full-text available

Late Quaternary paleoceanography of the Solomon and New Guinean Seas (Woodlark and Manus Basins) by...

January 1993

По соотношению видов планктонных фораминифер выявлены коле¬бания среднегодовой температуры поверхностной воды за последние 30 тыс. лет. Амплитуда колебаний температуры в Западном Вудларке составляет около 3°С, а в котловине Манус около 4,5*С. Эти амплитуды выше, чем по данным предыдущих исследований в соседних акваториях, и приближаются к температурным колебаниям на Новой Гвинее. В позд¬нем ... [Show full abstract] плейстоцене (30-10 тыс. л.н.) реконструировано два пика похолода¬ния 19,5 и 13 тыс. л.н. В пределах голоцена слабо проявился теплый интервал 10-8,5 тыс. л.н., затем следовал холодный интервал с миниму¬мом 8 тыс. л.н. и сильное потепление с пиком 5 тыс. л.н., когда температу¬ра достигла современного уровня или несколько превысила его.

Article

Paleoecological Relations of Foraminifera in a Desert‐Enclosed Sea ‐The Gulf of Aqaba (Elat), Red Se...

June 2008 · Marine Ecology

Planktonic and benthonic foraminifera live in the desert-enclosed, hypersaline and oligotrophic Gulf of Aqaba and northernmost Red Sea near the edge of their ecological tolerance. Marked changes in foraminiferal abundance patterns in the past, resulting from hydrological shifts related to global climatic fluctuations, facilitate a high-resolution ecostratigraphic subdivision of deep-sea records ... [Show full abstract] covering the last 150,000 years. Of particular significance are the foraminiferal plankton/benthos ratios, the presence/absence pattern of such species as Globigerinoides sacculifer, as well as the frequency variation of Globigerina bulloules-falconensis, Buliminacea, Miiiolacea and various “rotaliform” species. Paleoceanographic interpretation of the shifts in assemblage composition and of stable oxygen isotope data obtained on planktonic foraminifera and pteropods indicates that during glacial intervals - because of global cooling, lowered sea-level and reduced water exchange at the straits of Bab-el-Mandeb - the temperature of the upper waters fell by about 4–6 oC (to 15–17 oC), salinity rose by about 10%o to more than 50%0 while residence time of the water became longer and the input/output ratio of nutrients became higher. As a consequence, fertility of the photic zone was higher, the organic content of the sediments increased and oxygen levels in the deep basin became reduced. Thus, sea level-oscillations and strait-dynamics played a major role in the foraminiferal paleoecology of the Red Sea.

Article

Full-text available

Biotic and Paleoceanographic Changes Across the Late Cretaceous Oceanic Anoxic Event 2 in the Southe...

September 2022 · Paleoceanography and Paleoclimatology

The latest Cenomanian to Santonian sedimentary record recovered at IODP Expedition 369 Site U1513 in the Mentelle Basin (SE Indian Ocean, paleolatitude 60°S at 85 Ma) is studied to interpret the paleoceanographic evolution in the Southern Hemisphere. The planktonic foraminiferal assemblage changes, the depth ecology preferences of different species, and the surface and seafloor temperature ... [Show full abstract] inferred from the stable isotopic values measured on foraminiferal tests provide meaningful information to the understanding of the Late Cretaceous climate. The hothouse climate during the Turonian-Santonian, characterized by weak latitudinal temperature gradients and high atmospheric CO2 concentrations, is followed by a progressive cooling during the Campanian. At Site U1513 the beginning of this climatic transition is nicely recorded within the Santonian, as indicated by an ∼1‰ increase in δ18O values of planktonic foraminifera suggesting a decline in surface water paleotemperatures of 4°C. The onset of cooling is mirrored by changes in the planktonic foraminiferal assemblages including extinctions among surface and deep dwellers, appearances and diversification of newly evolving taxa, and changes from predominantly epifaunal oxic to infaunal dysoxic/ suboxic taxa among co-occurring benthic foraminifera. Overall, the data presented here document an interval in the Santonian during which the rate of southern high latitude cooling increased. Both surface and bottom waters were affected, although the cooling signal is more evident in the data for surface waters. This pattern of cooling ascribes the deterioration of the Late Cretaceous climate to decreased CO 2 in the atmosphere and changes in the oceanic circulation correlated with enhanced meridional circulation.