Download or read book Cenozoic Deep sea Benthic Foraminifera written by K. G. Miller and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cenozoic Cosmopolitan Deep water Benthic Foraminifera written by Frank P. C. M. Van Morkhoven and published by . This book was released on 1986 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cenozoic Record of Elongate Cylindrical Deep sea Benthic Foraminifera in the Southern and North Pacific Oceans and the Impact of the Early Eocene Global Warming Events written by Liesbeth Marie-Thérèse Karel Van Kerckhoven and published by . This book was released on 2014 with total page 463 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study was undertaken as a contribution to trying to determine the causes of the late Pliocene-middle Pleistocene extinction of a group of elongate deep-sea benthic foraminifera with specialised apertures (the “Extinction Group”, EG). The full Cenozoic evolutionary history of the EG was documented in the Southern and North Pacific Oceans in an attempt to identify palaeoenvironmental drivers of evolution of this group. A second objective was to assess whether the EG species were impacted by the late Palaeoecene-early Eocene warm events, like the ~30 % of deep-sea benthic foraminifera that became extinct during the Palaeocene/Eocene thermal maximum (PETM). The EG consists of the families Chrysalogoniidae, Glandulonodosariidae, Stilostomellidae, Ellipsoidinidae, Pleurostomellidae, Plectofrondiculariidae and several species from the Family of Nodosariidae. In this study, I recorded 102 species of the EG, including 15 taxa that had not been recognised previously. Five of these have now been formerly described as new species – Anastomosa boomgaarti Hayward and Van Kerckhoven, 2012; Anastomosa loeblichi Hayward and Van Kerckhoven, 2012; Siphonodosaria robertsoni Hayward and Van Kerckhoven, 2012; Ellipsoidella tappanae Hayward and Van Kerckhoven, 2012; Nodosarella kohli Hayward and Van Kerckhoven, 2012. Census counts on 98 EG species in 211 faunal samples (>63 mm) between the early Palaeocene (~65.5 Ma) and middle Eocene (~40 Ma) in Southern Ocean ODP Sites 689 and 690, and North Pacific Ocean ODP Site 865 indicated that there were no extinctions of these taxa during the PETM, and only three EG species had their global lowest occurrences within 0.5 myr of the PETM. However, this extreme warm event did impact on EG faunal composition on a global scale, with Strictocostella spp. becoming less dominant to the advantage of pleurostomellids and several other EG taxa. In terms of abundances and species richness, the EG was not or only slightly impacted by the PETM, and impacts differed between regions. The increase in species richness at the start of the PETM in the Southern Ocean possibly reflects a survival mechanism of the EG to the changing environmental conditions. Census counts on 92 EG species in 160 faunal samples between the late Cretaceous (~67.9 Ma) and Pleistocene (~0.5 Ma) in Southern Ocean ODP Site 689 and North Pacific Ocean ODP Site 1211 confirmed the EG thrived during the middle Eoceneearly Oligocene and went through periods of enhanced turnover and faunal composition changes during the rapid Eocene/Oligocene cooling event and the middlelate Miocene coolings. The Oligocene announced the start of the “Tweenhouse World” during which relative abundances of the EG in the benthic foraminiferal fauna started to decrease. However, EG diversity remained high during the Oligocene worldwide, possibly as a survival mechanism to compete with the benthic foraminiferal species with new ecological strategies (phytodetritus-feeding). Miocene decreases in EG relative abundances were mostly marked at the abyssal location, where EG faunal composition also went through major changes at ~10 Ma. Both locations, at opposite sides of the world, had 52 EG species in common, including most of the most common species. Average EG species duration was ~25 myrs in the Southern Ocean, and ~27 myrs in the North Pacific Ocean, concurring with findings of previous Cenozoic studies on the EG. From these studies, I conclude that the EG was affected by both warming and cooling extreme events in the deep-sea, possibly indirectly via their food source, to which they were highly adapted with specialised apertural modifications. The repeated preferred targeting of the usually highly successful stilostomellids, suggests species from this family were most specialised and also more vulnerable to extreme changes in environmental conditions. The decline in EG abundance and diversity during the “Tweenhouse” and “Icehouse World” oceans and their eventual extinction during the Mid-Pleistocene Transition were likely related to progressive and episodic global cooling impacting on the food source of this specialised group of deep-sea benthic foraminifera.

Download or read book Atlas of Benthic Foraminifera written by Ann Holbourn and published by John Wiley & Sons. This book was released on 2013-04-03 with total page 1115 pages. Available in PDF, EPUB and Kindle. Book excerpt: An up-to-date atlas of an important fossil and living group, with the Natural History Museum. Deep-sea benthic foraminifera have played a central role in biostratigraphic, paleoecological, and paleoceanographical research for over a century. These single–celled marine protists are important because of their geographic ubiquity, distinction morphologies and rapid evolutionary rates, their abundance and diversity deep–sea sediments, and because of their utility as indicators of environmental conditions both at and below the sediment–water interface. In addition, stable isotopic data obtained from deep–sea benthic foraminiferal tests provide paleoceanographers with environmental information that is proving to be of major significance in studies of global climatic change. This work collects together, for the first time, new morphological descriptions, taxonomic placements, stratigraphic occurrence data, geographical distribution summaries, and palaeoecological information, along with state-of-the-art colour photomicrographs (most taken in reflected light, just as you would see them using light microscopy), of 300 common deep-sea benthic foraminifera species spanning the interval from Jurassic - Recent. This volume is intended as a reference and research resource for post-graduate students in micropalaeontology, geological professionals (stratigraphers, paleontologists, paleoecologists, palaeoceanographers), taxonomists, and evolutionary (paleo)biologists.

Download or read book The Last Global Extinction Mid Pleistocene of Deep Sea Benthic Foraminifera Chrysalgoniidae Ellipsoidindae Glandulonodosariidae Plectofrondiculariidae Pleurostomellidae Stilostomellidae Their Late Cretaceous Cenozoic History and Taxonomy written by A. Van Ginkel and published by . This book was released on 2013-02-01 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proxies in Late Cenozoic Paleoceanography written by C. Hillaire-Marcel and published by Elsevier. This book was released on 2007-05-25 with total page 863 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present volume is the first in a series of two books dedicated to the paleoceanography of the Late Cenozoic ocean. The need for an updated synthesis on paleoceanographic science is urgent, owing to the huge and very diversified progress made in this domain during the last decade. In addition, no comprehensive monography still exists in this domain. This is quite incomprehensible in view of the contribution of paleoceanographic research to our present understanding of the dynamics of the climate-ocean system. The focus on the Late Cenozoic ocean responds to two constraints. Firstly, most quantitative methods, notably those based on micropaleontological approaches, cannot be used back in time beyond a few million years at most. Secondly, the last few million years, with their strong climate oscillations, show specific high frequency changes of the ocean with a relatively reduced influcence of tectonics. The first volume addresses quantitative methodologies to reconstruct the dynamics of the ocean andthe second, major aspects of the ocean system (thermohaline circulation, carbon cycle, productivity, sea level etc.) and will also present regional synthesis about the paleoceanography of major the oceanic basins. In both cases, the focus is the “open ocean leaving aside nearshore processes that depend too much onlocal conditions. In this first volume, we have gathered up-to-date methodologies for the measurement and quantitative interpretation of tracers and proxies in deep sea sediments that allow reconstruction of a few key past-properties of the ocean( temperature, salinity, sea-ice cover, seasonal gradients, pH, ventilation, oceanic currents, thermohaline circulation, and paleoproductivity). Chapters encompass physical methods (conventional grain-size studies, tomodensitometry, magnetic and mineralogical properties), most current biological proxies (planktic and benthic foraminifers, deep sea corals, diatoms, coccoliths, dinocysts and biomarkers) and key geochemical tracers (trace elements, stable isotopes, radiogenic isotopes, and U-series). Contributors to the book and members of the review panel are among the best scientists in their specialty. They represent major European and North American laboratories and thus provide a priori guarantees to the quality and updat of the entire book. Scientists and graduate students in paleoclimatology, paleoceanography, climate modeling, and undergraduate and graduate students in marine geology represent the target audience. This volume should be of interest for scientists involved in several international programs, such as those linked to the IPCC (IODP – Integrated Ocean Drilling Program; PAGES – Past Global Changes; IMAGES – Marine Global Changes; PMIP: Paleoclimate Intercomparison Project; several IGCP projects etc.), That is, all programs that require access to time series illustrating changes in the climate-ocean system. Presents updated techniques and methods in paleoceanography Reviews the state-of-the-art interpretation of proxies used for quantitative reconstruction of the climate-ocean system Acts as a supplement for undergraduate and graduate courses in paleoceanography and marine geology

Download or read book Cenozoic Deep water Agglutinated Foraminifera in the North Atlantic written by Michael Anthony Kaminski and published by . This book was released on 1987 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cenozoic (predominantly Paleogene) "flysch-type" agglutinated foraminiferal assemblages and their modern analogs in the North Atlantic and adjacent areas have been studied to provide an overview of their spatial and temporal distribution and utility for paleoenvironmental analysis. Over 200 species of agglutinated foraminifera have been recognized in Paleogene sediments from North Atlantic and Tethyan basins. This unified taxonomic data base enables the first general synthesis of biostratigraphic, paleobiogeographic and paleobathymetric patterns in flysch-type agglutinated assemblages from upper Cretaceous to Neogene sediments in the North Atlantic. The majority of taxa are cosmopolitan, but latitudinal, temporal and depth-related trends in diversity and species composition are observed among flysch-type assemblages. Modern deep-sea agglutinated foraminiferal faunas provide an analog to fossil flysch-type assemblages and serve as models for paleoecologic studies. Core-top samples from the Panama Basin, Gulf of Mexico and Nova Scotian continental rise were examined in order to determine the habitats of modern species of agglutinated foraminifera. The ecology of modern taxa provides constraints on the paleoenvironmental significance of fossil agglutinated assemblages in the North Atlantic, and their utility for paleoceanography. Towards this end, spade core samples from a 3912 m deep station in the Panama Basin were studied to determine abundance and microhabitat partitioning among living agglutinated foraminiferal populations and the preservation of dead assemblages. The genera Dendrophrya, Cribrostomoides and Ammodiscus have epifaunal habitats and the genus Reophax is predominantly infaunal. Species of Reophax are probably responsible for fine reticulate burrows observed in xradiographs. An experiment using recolonization trays in the Panama Basin was designed to identify opportunistic species of benthic foraminifera, and to assess the rate at which a population can colonize an abiotic substrate. The most successful colonizer at this site is Reophax, while Dendrophrya displays the lowest capability for dispersal. After nine months the abundance of living individuals in sediment trays was one-tenth to one-third that of background abundance, but the faunal diversity did not differ greatly from control samples. Recolonization by benthic foraminifera is more rapid than among macrofaunal invertebrates. Modern agglutinated assemblages from the Louisiana continental slope were examined to determine changes in species composition associated with hydrocarOrganic- bon seeps. rich substrates are characterized by a decrease in astrorhizids and an increase in trochamminids and textulariids. Highly organicenriched substrates with chemosynthetic macrofauna are dominated by Trochammina glabra and Glomospira charoides. The biostratigraphy of fossil agglutinated foraminifera in the North Atlantic is based on detailed analysis of 670 samples from 14 wells and one outcrop section, and examination of additional picked faunal slides from industry wells. Local biostratigraphic schemes are established for Trinidad, Northern Spain, the Labrador Sea, Baffin Bay, and the Norwegian-Greenland Sea. These schemes are compared with existing biostratigraphic frameworks from the Labrador Margin, the North Sea, and the Polish Carpathians. A number of species show utility for biostratigraphy in the North Atlantic. Lineages which contain stratigraphically useful species include the Haplophragmoides cf. glabra - Reticulophragmium group, Hormosina, and Karreriella. Significant faunal turnovers are observed at the Paleocene/Eocene, Ypresian/ Lutetian and Eocene/Oligocene boundaries. A reduction in diversity occurs at the Paleocene/Eocene boundary in all bathyal sections studied, and agglutinated forminifera disappear entirely from abyssal low-latitude DSDP sites. In the Gibraltar Arch, the Labrador Sea and the Norwegian-Greenland Sea, the Ypresian/Lutetian boundary is characterized by a Glomospira-facies. This is attributed to a rise in the lysocline associated with increased paleoproductivity and the NP14 sealevel lowstand. The Eocene/Oligocene boundary is delimited by another major turnover and the last occurrence of a number of important taxa. At Site 647, where recovery across the Eocene/Oligocene boundary was continuous, the change from an Eocene agglutinated assemblage to a predominantly calcareous assemblage in the early Oligocene took place gradually, over a period of about 4 m.y. The rate of change of the faunal turnover accelerated near the boundary. This faunal turnover is attributed to changes in the preservation of agglutinated foraminifera, since delicate species disappeared first. Increasingly poorer preservation of agglutinated foraminifera in the late Eocene to earliest Oligocene reflected the first appearance of cool, nutrient-poor deep water in the southern Labrador Sea. The approximately coeval disappearance of agglutinated assemblages along the Labrador Margin was caused by a regional trend from slope to shelf environments, accentuated by the "mid"--Oligocene sealevel lowstand. Paleobiogeographic patterns in flysch-type foraminifera were examined in the Paleogene of the North Atlantic. In the early Paleogene, general decrease in diversity is observed from low to high latitudes and from the continental slope to the deep ocean basins. The diversity of these microfossils declines in most studied sections throughout the Paleogene. The last common occurrence (LCO) of flysch-type foraminifera in the North Atlantic exhibits a pattern of diachrony with latitude and depth. Extinctions occurred first at abyssal depths and at low latitudes. Agglutinated assemblages disappeared from the northern Atlantic region in the early Oligocene. However, the deep Norwegian-Greenland Sea served as a refuge for many species, and agglutinated assemblages persisted there until the early Pliocene. The LCO of flysch-type foraminifera may have been related to the transition from a warm, sluggish deep sea environment to a cooler, more oxygenated, thermohaline-driven deep circulation pattern caused by bipolar cooling. The paleobathymetry of Paleogene agglutinated assemblages in the North Atlantic differs from Cretaceous patterns. Shallow-water assemblages of Paleogene age contain robust astrorhizids, loftusiids and coarse lituolids, whereas deep assemblages possess delicate tubular forms, ammodiscids, and smooth lituolids. At low latitudes, upper bathyal assemblages contain abundant calcareous ataxophragmiids. Paleocene paleobathymetric patterns in the North Atlantic compare well with patterns observed in the Carpathian troughs. The utility of agglutinated foraminifera in paleoceanography is illustrated by a study of the paleocommunity structure of fossil assemblages in ODP Hole 646B on the Eirik Ridge (Labrador Sea). The synecology of benthic foraminifera in Hole 646B places constraints on the history of Denmark Straits Overflow Water over that site. Below seismic horizon "R3", a Miocene assemblage contains smooth agglutinated species with abundant Nuttalides umbonifera, indicating corrosive bottom water and tranquil conditions. A coarse agglutinated assemblage with "NADW-type" calcareous benthics is observed above the seismic horizon. This faunal turnover at horizon "R3" reflects the onset (or renewal) of significant Denmark Straits overflow at -7.5 Ma. Agglutinated species disappear between reflector "R2", and the base of the sediment drift, indicating a change in deep-water properties associated with the re-opening of the Mediterranean. The onset of drift sedimentation at the Eirik Ridge is dated at -4.5 Ma. Drift formation ceased at -2.5 Ma, concomitant with the appearance of ice-rafted sediments.

Download or read book Cenozoic deep sea benthic foraminifers written by E. THOMAS and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Studies of Cenozoic Deep sea Benthonic Foraminifera in the Southern Ocean written by Bruce Hayward Corliss and published by . This book was released on 1978 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Climate Transitions Across the Cenozoic written by and published by . This book was released on 2008 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Cenozoic climate record derived from the oxygen isotope ratios of benthic foraminifera (delta18Ob) displays several, short term steps signifying the glaciation of Antarctica (~33.7 Ma) and the development (~2.7 Ma) and intensification (~0.9 Ma) of large-scale northern hemisphere glaciation (NHG), termed hereafter the late Pliocene transition (LPT) and mid-Pleistocene transition (MPT), respectively. The interpretation of the delta18Ob record, which is controlled by both temperature and the oxygen isotopic composition of seawater (delta, omega), is, however, not straightforward. In the work presented here, I:(1) used Mg/Ca benthic foraminiferal paleothermometry paired with delta18Ob to construct high resolution records of deep ocean temperature and global ice volume to understand the underlying mechanisms of Pliocene-Pleistocene climate transitions and (2) developed a new salinity independent paleothermometer based on Sr/Ca ratios in marine gastropods and examined its potential for Cenozoic low-latitude sea surface temperature reconstructions and I constructed and applied a new regional Mg/Ca-temperature calibration based on downcore Mg/Ca variations to encompass changes in temperature and carbonate saturation in deep Atlantic Ocean. The new, high resolution bottom water temperature record from North Atlantic Deep Sea Drilling Project site 607 indicates that the deep ocean cooled across both the LPT and MPT. The cooling across the MPT preconditioned the high latitudes for ice-sheet growth by modifying heat transport through changes in meridional temperature gradients. Across the LPT, the mean trend in sea level decreased by 20+/-25m whereas the MPT is associated with an increase in glacial-interglacial amplitude of sea level. I propose that the MPT is related to a change in ice sheet dynamics, specifically growth of thicker ice sheets, and that a threshold response to high-latitude cooling is not sufficient to explain the MPT. The Sr/Ca- temperature calibration study, based on the marine gastropod Conus ermineus, shows that strontium incorporation into the aragonitic gastropod shell is most likely driven by a temperature influence on growth rate. To minimize the ontogenetic effect, I separated the Sr/Ca-temperature calibration into juvenile and adult growth stages. The application of the new low-latitude paleothermometer to fossil specimens shows that the low latitudes cooled along with high latitudes throughout the Cenozoic.

Download or read book Cenozoic Records of Seawater Chemistry written by Elaine M. Mawbey and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The ratios of trace metals to calcium in the calcium carbonate tests of benthic foraminifera have been used as palaeoceanographic proxies for several decades and are now routinely used to reconstruct past climate change on a variety of Cenozoic timescales. Recent research, however, reveals gaps in our understanding of the effects of oceanic variables such as temperature and carbonate saturation state on these trace metal ratios, which limits their application as proxies. Additional uncertainties arise because of physiological effects ("vital effects") and microhabitat of the living foraminifera. Moreover, much of what is known about trace metal uptake into benthic foraminiferal calcite is derived from modern core-top calibrations and laboratory experiments and it is unknown as to what extent our understanding from these models can be applied to the early and mid Cenozoic. This thesis attempts to address some of these questions using a novel depth transect approach and presenting benthic foraminiferal trace metal records across three major Cenozoic climate change events from Ocean Drilling Program (ODP) deep sea core material. The events are: (i) The Eocene-Oligocene transition (EOT), (ii) The Oligocene- Miocene boundary event (Mi-1) and (iii) The Middle Miocene Climatic Transition (MMCT). These records have allowed examination of the validity of the application of current knowledge of benthic foraminiferal trace metal proxies to Cenozoic records, and also the comparison of the records of two different benthic foraminiferal species, which has shed new light on the importance of foraminiferal habitat in the interpretation of the proxy data. The identification of a dissolution effect operating on benthic foraminiferal Mg/Ca in undersaturated waters has allowed a reasonable estimate of cooling (~2-3 ̊C) to be obtained from deep-sea records across the Eocene-Oligocene Transition. The transient glaciation at the Oligocene-Miocene boundary is estimated to comprise of a deep-sea cooling of ~2°C and a sea level decrease of ~80 metres based on Oridorsalis umbonatus Mg/Ca. Comparison of new Middle Miocene trace metal records across a water depth transect has shed light on the relative interplay of temperature and saturation state on published Mg/Ca records, enabling more accurate estimates of temperature and ice volume change. The new interpretations suggest that deep sea temperatures cooled by ~4.5C, and sea level fell by 70-100 metres between 16.2 and 11.6 Ma. The recently developed paired Mg/Ca-Li/Ca approach to calculating simultaneous variations in bottom water temperature and saturation state has been used to assess inter-basinal differences in water mass composition for the first time. Down-core benthic foraminiferal Li/Ca records from Ceara Rise Sites do not behave as expected, indicating that there may be times when this proxy is affected by an additional environmental parameter. This is tentatively suggested to be a growth-rate related oxygenation signal. U/Ca in benthic foraminifera does not appear to work as a saturation state proxy in these records, again indicating either different behaviour to the observed modern behaviour, or additional factors absent from the modern calibration, such as bottom water oxygenation. Benthic foraminiferal Sr/Ca follows the linear negative water-depth relationship of Lear et al., (2003) suggesting a pressure-related effect. This study demonstrates that benthic foraminiferal trace metal chemistry can be used to provide information about climate events in the Cenozoic, however additional empirical work is required to fully understand the systematics of trace metal incorporation into benthic foraminiferal tests.

Download or read book Late Cenozoic Benthic Foraminifers of the HLA Borehole Series Beaufort Sea Shelf Alaska written by Kristin A. McDougall and published by . This book was released on 1994 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Benthic foraminiferal assemblages in marine strata of 18 boreholes in the Beaufort Sea shelf are correlated with late Cenozoic marine transgressions. Paleoenvironmental interpretations of the transgression are based on these benthic foraminifers.

Download or read book Survival Under Stress written by Tanneke Johanna Kouwenhoven and published by . This book was released on 2000 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Late Cenozoic Benthic Foraminifera of the Norwegian Greenland Sea written by Paul Edward Belanger and published by . This book was released on 1984 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Late Cenozoic Benthic Foraminifera written by Hans Petter Sejrup and published by . This book was released on 1994 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cenozoic Deep sea Benthic Forminifers written by Ellen Thomas and published by . This book was released on 1996 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ecology and Palaeoecology of Benthic Foraminifera written by John W. Murray and published by Routledge. This book was released on 2014-10-13 with total page 878 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is an important and authoritative review of foraminiferal ecology, the first for over a decade. Professor Murray relates ecological data on living forms of foraminifera to the palaeoecology of fossil species, and defines in detail areas of global distribution.