Cenozoic Planktonic Foraminifera Research Articles

The impact of Cenozoic cooling on assemblage diversity in planktonic foraminifera.

The Cenozoic planktonic foraminifera (PF) (calcareous zooplankton) have arguably the most detailed fossil record of any group. The quality of this record allows models of environmental controls on macroecology, developed for Recent assemblages, to be tested on intervals with profoundly different climatic conditions. These analyses shed light on the role of long-term global cooling in establishing the modern latitudinal diversity gradient (LDG)—one of the most powerful generalizations in biogeography and macroecology. Here, we test the transferability of environment-diversity models developed for modern PF assemblages to the Eocene epoch (approx. 56–34 Ma), a time of pronounced global warmth. Environmental variables from global climate models are combined with Recent environment–diversity models to predict Eocene richness gradients, which are then compared with observed patterns. The results indicate the modern LDG—lower richness towards the poles—developed through the Eocene. Three possible causes are suggested for the mismatch between statistical model predictions and data in the Early Eocene: the environmental estimates are inaccurate, the statistical model misses a relevant variable, or the intercorrelations among facets of diversity—e.g. richness, evenness, functional diversity—have changed over geological time. By the Late Eocene, environment–diversity relationships were much more similar to those found today.

Stable isotope analysis of Dacryoconarid carbonate microfossils: a new tool for Devonian oxygen and carbon isotope stratigraphy.

Dacryoconarids are extinct marine zooplankton known from abundant, globally distributed calcite microfossils in the Devonian, but their shell stable isotope composition has not been previously explored. Devonian stable isotope stratigraphy is currently limited to less common invertebrates or bulk rock analyses of uncertain provenance. As with Cenozoic planktonic foraminifera, isotopic analysis of dacryoconarid shells could facilitate higher-resolution, geographically widespread stable isotope records of paleoenvironmental change, including marine hypoxia events, climate changes, and biocrises. We explored the use of Dacryoconarid isotope stratigraphy as a viable method in interpreting paleoenvironments. We applied an established method for determining stable isotope ratios (δ(13) C, δ(18) O values) of small carbonate microfossils to very well-preserved dacryoconarid shells. We analyzed individual calcite shells representing five common genera using a Kiel carbonate device coupled to a MAT 253 isotope ratio mass spectrometer. Calcite shell δ(13) C and δ(18) O values were compared by taxonomic group, rock unit, and locality. Single dacryoconarid calcite shells are suitable for stable isotope analysis using a Kiel-IRMS setup. The dacryoconarid shell δ(13) C values (-4.7 to 2.3‰) and δ(18) O values (-10.3 to -4.8‰) were consistent across taxa, independent of shell size or part, but varied systematically through time. Lower fossil δ(18) O values were associated with warmer water temperature and more variable δ(13) C values were associated with major bioevents. Dacryoconarid δ(13) C and δ(18) O values differed from bulk rock carbonate values. Dacryoconarid individual microfossil δ(13) C and δ(18) O values are highly sensitive to paleoenvironmental changes, thus providing a promising avenue for stable isotope chemostratigraphy to better resolve regional to global paleoceanographic changes throughout the upper Silurian to the upper Devonian. Our results warrant further exploration of dacryoconarid stable isotope proxy sensitivity, the isotopic contrast among dacryoconarids, other taxa, and bulk rock, as well as other potential dacryoconarid proxies (Mg/Ca, Sr/Ca, (87) Sr/(86) Sr, microlaser and ion microprobe isotope techniques, and clumped isotopes) for stratigraphic research.

Presentation of the 2013 Charles Schuchert Award of the Paleontological Society to Bridget S. Wade

The Charles Schuchert Award is presented to a person under 40 whose work early in his or her career reflects excellence and promise in the science of paleontology, and thus reflects the objectives and standards of the Paleontological Society. Dr. Bridget S. Wade is the 2013 recipient of the Charles Schuchert Award. Since receiving her Ph.D. Bridget has produced outstanding achievements in micropaleontology and paleoceanography. She is internationally recognized for her research on Paleogene climate and oceanography, Cenozoic planktonic foraminiferal taxonomy, evolution, and extinction. She has broadened her research skills through numerous collaborations and work at multiple institutions, including Leeds University (B.Sc., Advanced Research Fellowship), the University of Edinburgh (Ph.D.), Cardiff University (NERC Postdoctoral Fellowship), Rutgers University (Lindemann Research Fellowship), and Texas A&M University (Assistant Professorship). She recently was appointed to a Professorship in the Department of Earth Sciences at University College, London. Since receiving her Ph.D. in 2001, Bridget's research quality and productivity have been consistently high, having published a total of 41 papers in high profile, peer reviewed journals and among these she is the lead author on 15 papers. Her research integrates geology, foraminiferal taxonomy and biostratigraphy with stable isotope geochemistry, astrochronology, and magnetostratigraphy, the latter of which enables high-resolution age stratigraphic control. Bridget's extensive field work includes ocean drilling and piston coring cruises, field work in Cyprus, Italy, Tanzania, Mozambique, Trinidad, Puerto Rico, Australia, and various regions of the U.S. has provided detailed links between biotic, paleoclimatic and paleoceanographic events that occurred during the Cenozoic. Her research has led to significant improvements in the Cenozoic time scale and increased accuracy and resolution of the timing of evolution, extinction and acme events for Cenozoic planktonic foraminifera. Bridget is a leading contributor to studies of critical intervals of climate change during the Cenozoic. Some of Bridget's more …

Investigation of pre-extinction dwarfing in Cenozoic planktonic foraminifera

We propose a phenomenon termed “pre-extinction dwarfing” in Cenozoic planktonic foraminifera. High-resolution morphometric analysis shows a reduction in maximum or mean test size in the 2–20 kyr interval preceding the extinction of Pliocene Globorotalia exilis and Globorotalia miocenica from the Caribbean Sea and middle Eocene Morozovelloides crassatus from the western North Atlantic. Through a series of case studies and review of qualitative observations from the literature, we suggest that dwarfing occurs in a number of species of planktonic foraminifera foreshadowing their demise and that such size changes are not just a phenomenon associated with mass extinction events. We propose that this is a common stress-induced pattern that results in diminutive size in the pre-extinction interval.

Planktonic foraminiferal biostratigraphy and mechanisms in the extinction of Morozovella in the late middle Eocene

The muricate planktonic foraminiferal genera Morozovella and Acarinina were abundant and diverse during the upper Palaeocene to middle Eocene and dominated the tropical and subtropical assemblages. A significant biotic turnover in planktonic foraminifera occurred in the latest middle Eocene with a notable reduction in the acarininid lineage and the extinction of the morozovellids. These genera are extensively employed as palaeoclimatic and biostratigraphic markers and, therefore, this turnover episode is an important event in the record of the Cenozoic planktonic foraminifera. Sediments from the western North Atlantic (Ocean Drilling Program Site 1052) were examined in order to investigate these extinction events, in terms of both timing and mechanisms. Biostratigraphic events of the middle and late Eocene have been examined with a sampling resolution of approximately 3 kyr. These have been calibrated to the magneto- and astrochronology to accurately define the timing of key biostratigraphic events, particularly the extinction of Morozovella spinulosa which is a distinct biomarker for late middle Eocene sediments. High-resolution biostratigraphy reveals that the extinctions in the muricate group occurred in a stepwise form. The large acarininids ( Acarinina praetopilensis) terminate 10 kyr prior to the extinction of M. spinulosa and small acarininids ( Acarinina medizzai and Acarinina echinata) continue into the upper Eocene. High-resolution stable isotope analyses have been conducted on planktonic and benthic foraminifera from the western North Atlantic to reconstruct sea surface temperatures (SSTs) and deep water temperatures and the structure of the water column around this major biotic turnover. Whilst the extinctions of M. spinulosa and A. praetopilensis occur during a long-term cooling trend, the biotic turnover in the muricate group does not appear to be related to significant climatic change. Sea surface temperatures decrease slowly prior to the extinction events, and there is no evidence for a large-temperature shift associated with the faunal changes. The turnover event was therefore probably related to the increased surface water productivity and the deterioration of photosymbiotic partnerships with algae.

Species Survivorship in the Cenozoic Planktonic Foraminifera: A Test of Exponential and Weibull Models

The species survivorship curve for Cenozoic planktonic foraminifera was fitted to exponential (age-independent) and Weibull (age-dependent) models. Model fits that account for censorship bias have substantially lower slopes (extinction probabilities) than suggested by censored data. The best-fit Weibull model has a shape parameter significantly greater than one (,B = 1.19), which normally indicates an age-dependent increasing probability of extinction. Deviation of Weibull /3 from 1.0 (exponential case) seems closely related to temporal variation in records of very short-lived taxa (?1 my). The shape of the curves are not sensitive to Corrected Species Survivorship adjustment of longevities, but may reflect taxonomic procedure or temporal variability in extinction probability.

Neptune: A marine micropaleontology database

Marine micropaleontology must in the future provide more precise chronologic and paleoenvironmental information, which in turn must be based on better, more consistent taxonomic and distributional data. Better tools for synthesis and standardization of this data are needed, as the ever expanding published literature is rapidly becoming unmanageable by purely manual compilation methods. The micropaleontology group at the ETH has developed a large relational database of marine microfossil data to partially meet this need. It currently contains biogeographic data on the distribution in Deep Sea Drilling Project (DSDP) and Ocean Drilling Program (ODP) holes of nearly 8,000 species of Cenozoic planktonic foraminifera, radiolaria, diatoms and calcareous nannofossils. The database also includes full stratigraphic occurrence (range chart) data for these fossil groups from more than 100 selected Neogene holes. A particular feature of the database is that all sample information and species names in the original reports are linked to newly created, updatable, comprehensive age models and synonymy lists which reflect modern chronology and taxonomic usage. Searches of the database automatically make use of this information in producing reports. Species ' occurrences, including first and last occurrence information, can be further analyzed using external spreadsheet and statistics packages; plotted by mapping programs; or displayed by a new program which creates composite age-range charts.

Macro- and microevolutionary aspects of the early Paleogene recovery of the planktonic foraminifera

To date, most macroevolutionary studies have focused on taxonomic data; there are very few data sets that provide a large enough statistical population for extensive macroevolutionary studies involving direct morphometric data. The Cenozoic planktonic foraminifera are exceptional in this regard. Digitally captured shape descriptions of 342 species of Cenozoic planktonic foraminifera have been combined with the available data on their phylogenetic relationships to examine the interplay between speciation rates, size change, and various geometric characters. The results tend, at least for the planktonic foraminifera, to support Stanley's (1973) hypothesis regarding the causal mechanisms behind Cope's Rule. The tendency toward size increase may result from the disadvantages of large size during times of mass extinction rather than from the (conventionally assumed) advantages of larger size.Additional results derived from morphotypic longevities and morphotypic turnover rates suggest an enhanced probability of speciation early in the Cenozoic, and enhanced longevity in the later Cenozoic.Microevolutionary studies of patterns of changing variance within the Paleocene and Eocene genus Morozovella suggest that conventional foraminiferal taxonomic practice may not accurately reflect biological realities within the group, thus implying that our macroevolutionary results might be interpreted in other ways.Paedomorphosis has now been seen in several foraminiferal lineages, including Morozovella angulata, a focus of the present study. Isotopic data (Shackleton, Corfield, and Hall, 1985) suggests that evolution of this group is accompanied by the invasion of a stratified water column. These observations suggest that one might look for systematic macroevolutionary morphologic tendencies in chamber expansion rate and size as a guide to understanding paleoecological conditions. It also seems reasonable to suggest that the complex morphological changes seen in the morozovellids may not represent morphological adaptation, but resource-related heterochronic shifts with ancillary morphological consequences.

A case for subgenera in a foraminiferal classification

Abstract. There has been a progression in palaeobiological classifications from the more primitive empirical “stamp collecting” stage where similar shapes were grouped together, to the more sophisticated phylogenetic classifications where supposed genetically related foraminiferal taxa are categorised together. But how do we know that certain extinct taxa were genetically related? This is a major problem where a number of factors interplay together: a belief in evolution, the experience of the operator and consequent recognition of phyletic lineages. In the study of Cenozoic planktonic foraminifera we are fortunate to have recognised a number of now well established lineages; also we have some data on amino-acids found in the tests of living species (King and Hare, 1972) which range back well into the Neogene. These latter data not only provide us with essential genetic information but they also give us confidence when dealing with the classification of extinct species.So how do we build this evolutionary knowledge into a classification? Clearly, genetically related species can be grouped together into subgenera, and related subgenera into broader genera. In their classification Loeblich and Tappan (1988) held a different view and decided not to use subgenera because (1) their usage produces an unwieldy classification, and (2) lineage concepts change when additional data are collected. If we follow their classification, then when you read about Globorotalia menardii, Globorotalia fohsi and Globorotalia hirsuta you could assume that they are closely related; this is not true. The three species have similar test morphologies but these have resulted from iterative. . .

Lithium‐to‐calcium ratios in Modern, Cenozoic, and Paleozoic articulate brachiopod shells

Li/Ca ratios in modern brachiopod shells generally correlate inversely with growth temperature, ranging from ∼20 µmol/mol at 30°C to ∼50 µmol/mol at 0°C with no apparent interspecific offsets. Causes of the temperature effect on Li/Ca ratios are not yet understood. Cenozoic brachiopod Li/Ca ratios average ∼30 µmol/mol, similar to the average observed in modern brachiopods. Relatively constant Li/Ca ratios for Eocene to Pleistocene nonluminescent brachiopod shells, consistent with previous observations of Cenozoic planktonic foraminifera, support the conclusion of little variation in Cenozoic seawater Li/Ca. Nonluminescent portions of Permian and Carboniferous brachiopods have Li/Ca ratios substantially lower (generally <10 µmol/mol) than modern, Cenozoic, or Devonian samples. Mass balance considerations, constrained by δ18O of brachiopods, suggest that low Li concentrations in Permo‐Carboniferous seawater could be the result of a lower flux of dissolved Li from the continents and/or a higher flux of Li from seawater to clastic marine sediments. Nonluminescent Devonian brachiopods from a single hand specimen have Li/Ca ratios around 70% of the modern average. These Li/Ca ratios can be explained by either somewhat higher temperature with constant seawater Li/Ca, somewhat lower seawater Li/Ca at constant temperature, or a combination of slightly elevated temperature and slightly lower seawater Li/Ca.

Chronostratigraphic Significance of Late Cenozoic Planktonic Foraminifera from Ventura Basin, California: Implications for Depositional History, Tectonic Reconstruction, and Exploration for Bathyal Clastic Reservoirs: ABSTRACT

A chronostratigraphic framework for the late Cenozoic borderland basins of central and southern California is compiled from evolutionary datums of temperate North Pacific planktonic foraminifera and paleoclimatically controlled coiling shifts in Neogloboquadrina pachyderma. All datums are calibrated against paleomagnetic and tephra stratigraphies, as well as established global time scales. The chronostratigraphic framework is applied to three key sections from the Ventura basin: Wheeler Canyon (containing the stratotypes for the Venturian and Wheelerian stages), Santa Paula Creek, and Balcom Canyon. Improved chronostratigraphic correlations are demonstrated for the interval between 0.6 and 3.0 Ma. Because borderland basins along this active continental margin contain thick, stratigraphically complex accumulations of basin fill, accurate and high-resolution chronostratigraphic correlations are needed to better reconstruct the depositional and paleoenvironmental history of this area. In addition, stratigraphic trapping of hydrocarbons in bathyal clastic reservoirs is a prominent feature in these borderland basins. Exploration strategies for these areas can be greatly improved by applying the proposed chronostratigraphic correlation to stratigraphic mapping on selected time horizons, development of improved depositional models, and better reconstructions of bathymetric and tectonic history. A geohistory plot for the central Ventura basin illustrates some of the benefits of the proposed chronostratigraphic framework by documenting andmore » constraining the timing of two episodes of basin subsidence during the Pliocene-Pleistocene.« less

Cenozoic Planktonic Foraminifera: A Paleobiogeographic Summary

The Study of Cenozoic planktonic foraminifera has benefited in the last 1–1/2 decades by Deep Sea Drilling retrieval of many cored sections from the major ocean basins of the world. The stratigraphy of planktonic foraminiferal species in these ocean basins has provided important data on evolutionary lineages of species and biostratigraphic utility of species. The geographic coverage of the oceans has given a clearer picture of the biogeography of species and of past oceanographic conditions. It has become clear that the evolution of planktonic foraminifera was controlled by oceanographic and climatic events related to the redistribution of land and sea. The purpose of this presentation is to summarize the major patterns of the paleobiogeography of planktonic foraminifera during the Cenozoic.

Surface Wall Texture and Evolutionary Classification of Cenozoic Planktonic Foraminifera: ABSTRACT

The classification most widely applied to Cenozoic planktonic Foraminifera employs relatively simple morphologic criteria, such as chamber shape and apertural position, to sort test forms into genera. Because the criteria are few and distinct, this traditional approach is easy to apply and has been generally accepted by stratigraphic paleontologists. Most morphologic features, however, evolved several times during the Cenozoic. Peripheral keels appeared independently at least eleven times. Form-genera based solely on such features are unavoidably polyphyletic. Surface wall texture, in contrast, has been evolutionarily conservative during the Tertiary. Once developed, the few basic wall-textural types persisted within lineages. A classification based primarily on surface wall textures and secondarily on gross morphology most accurately reflects patterns of descent recognized from species-by-species evaluation of End_Page 925------------------------------ ancestor-descendant relations and conveys important stratigraphic and paleoecologic information. Most Cenozoic species, for example, are usually assigned to either Globorotalia or Globigerina. Used in this way, these taxa are over-inclusive and provide no information beyond a mnemonic clue to apertural position. As appropriately modified, Globorotalia is exclusively a Neogene genus, and Paleogene species are assigned to Acarinina, Morozovella, and Planorotalites. Globigerina is largely a middle Tertiary taxon, containing only a few cool-water modern species; most late Neogene globigeriniforms belong in Neogloboquadrina or Globoturborotalita. An emphasis on phyletic species-grups is requisite for the development of multiple-phyletic zonations. End_of_Article - Last_Page 926------------

Diversity changes in the New Zealand Cenozoic planktonic foraminifera

Other| April 01, 1973 Diversity changes in the New Zealand Cenozoic planktonic foraminifera D. Graham Jenkins D. Graham Jenkins Search for other works by this author on: GSW Google Scholar Journal of Foraminiferal Research (1973) 3 (2): 78–88. https://doi.org/10.2113/gsjfr.3.2.78 Article history first online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation D. Graham Jenkins; Diversity changes in the New Zealand Cenozoic planktonic foraminifera. Journal of Foraminiferal Research 1973;; 3 (2): 78–88. doi: https://doi.org/10.2113/gsjfr.3.2.78 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyJournal of Foraminiferal Research Search Advanced Search Abstract Main cause of species diversity was paleotemperature; cryptogenic and evolutionary appearances and extinctions also influence diversity, diversity curve for Cenozoic given This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Cenozoic Planktonic Foraminiferal Zonation

The significant general features of the planktonic zones of the Cenozoic are discussed. Figures and ranges of important Cenozoic planktonic foraminifera are referred to the European geologic time scale combined with absolute chronology. Planktonic zonation for the Cenozoic is considered to have general world-wide uniformity, and thus provrovides a means of recognizing the standard European stages in open marine deeper-water facies of tropical areas of the world.--B.S.H