We review Phanerozoic sea-level changes [543 million years ago (Ma) to the present] on various time scales and present a new sea-level record for the past 100 million years (My). Long-term sea level peaked at 100 ± 50 meters during the Cretaceous, implying that ocean-crust production rates were much lower than previously inferred. Sea level mirrors oxygen isotope variations, reflecting ice-volume change on the 10 4 - to 10 6 -year scale, but a link between oxygen isotope and sea level on the 10 7 -year scale must be due to temperature changes that we attribute to tectonically controlled carbon dioxide variations. Sea-level change has influenced phytoplankton evolution, ocean chemistry, and the loci of carbonate, organic carbon, and siliciclastic sediment burial. Over the past 100 My, sea-level changes reflect global climate evolution from a time of ephemeral Antarctic ice sheets (100 to 33 Ma), through a time of large ice sheets primarily in Antarctica (33 to 2.5 Ma), to a world with large Antarctic and large, variable Northern Hemisphere ice sheets (2.5 Ma to the present).

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The Phanerozoic Record of Global Sea-Level Change

1. Introduction.- 2. Taxonomy and Species Features.- 2.1 Introduction.- 2.2 Species List.- 2.2.1 Spinose Planktonic Foraminifera.- 2.2.2 Non-spinose Planktonic Foraminifera.- 3. Collecting and Culture Methods.- 3.1 Introduction.- 3.2 Collection for Ecological Studies.- 3.3 Fixation and Storing of Samples.- 3.4 Laboratory Preparations.- 3.5 Collection for Physiological and Ecological Studies.- 3.5.1 Net Collection.- 3.5.2 SCUBA Collection.- 3.6 Isolation and Preparation for Maintenance Culture.- 3.7 Maintenance Cultures.- 3.8 Monitoring Vitality and Growth of the Cultures.- 3.9 Feeding Techniques.- 3.9.1 Algal Prey.- 3.9.2 Animal Prey.- 3.10 Cataloguing and Storing Shells.- 3.11 Summary.- 4. Cellular Ultrastructure.- 4.1 Introduction.- 4.2 Fixation of Planktonic Foraminifera for Fine Structure Analysis.- 4.3 Cytoplasmic Streaming.- 4.4 Peripheral Cytoplasm and Rhizopodial Morphology.- 4.4.1 Cytoskeletal Structures.- 4.4.2 Filaments.- 4.5 Fine Structure of Cytoplasmic Organelles.- 4.5.1 Nucleus.- 4.5.2 Mitochondria.- 4.5.3 Peroxisomes.- 4.5.4 Endoplasmic Reticulum, Golgi Complex, and Vacuolar System.- 4.5.5 Fibrillar Bodies.- 4.5.6 Lipids and Various Cytoplasmic Inclusions.- 4.6 Comparative Fine Structure Data of Benthic and Planktonic Species.- 4.7 Comparative Fine Structure of Planktonic Foraminifera and Radiolaria.- 4.8 Summary.- 5. Host and Symbiont Relationships.- 5.1 Introduction.- 5.2 Symbiosis, Commensalism and Parasitism.- 5.3 Symbiont Morphology and Structural Association with Host.- 5.3.1 Dinoflagellate Symbiont Fine Structure.- 5.3.2 Chrysophycophyte Symbiont Fine Structure.- 5.4 Symbiont and Host Physiological Interactions.- 5.5 Origin of Symbionts.- 5.6 Major Features of Algal Symbionts.- 5.7 Summary.- 6. Trophic Activity and Nutrition.- 6.1 Introduction.- 6.2 Natural Prey.- 6.3 Laboratory Studies of Trophic Activity.- 6.3.1 Prey Acceptance and Rate of Digestion.- 6.3.2 Cannibalism.- 6.3.3 Fine Structure Studies of Prey Capture and Digestion.- 6.3.4 Trophic Activity and Longevity.- 6.3.5 Laboratory Studies of Omnivorous Feeding.- 6.4 Prey Abundance and Foraminiferal Distribution.- 6.5 Predators on Planktonic Foraminifera.- 6.6 Comparative Data with Benthic Foraminifera and Radiolaria.- 6.7 Summary.- 7. Reproduction.- 7.1 Introduction.- 7.2 Gametogenesis.- 7.2.1 Light Microscopic Data.- 7.2.2 Fine Structure Data.- 7.3 Morphological Changes during Gametogenesis.- 7.4 Reproductive Cycles.- 7.5 Comparisons with Benthic Foraminifera and Radiolaria.- 7.6 Summary.- 8. Shell Ontogeny.- 8.1 Introduction.- 8.2 Ontogenetic Concept for Spinose Species.- 8.2.1 Five Stage Concept.- 8.2.2 Ontogeny of Globigerinoides sacculifer.- 8.3 Variations in Developmental Morphology of Spinose Species.- 8.4 Variations in Developmental Morphology of Non-spinose Species.- 8.5 Quantitative Ontogeny.- 8.6 Coiling Directions.- 8.7 Taxonomic Applications.- 8.8 Summary.- 9. Shell Architecture.- 9.1 Introduction.- 9.2 Chamber Deposition and Pore Formation.- 9.2.1 Chamber Formation in Non-spinose Species.- 9.2.2 Pore Formation and Wall Thickening.- 9.2.3 Keel Development.- 9.2.4 Pustule Formation.- 9.3 Chamber Formation in Spinose Species.- 9.3.1 Spine Types.- 9.4 Wall Thickening and Gametogenic Calcification.- 9.5 Physiological Mechanism and Rates of Calcification.- 9.6 Organic Composition of the Calcitic Wall.- 9.7 Resorption and Repair Processes.- 9.8 Abnormal Shell Growth.- 9.9 Summary.- 10. Ecology.- 10.1 Introduction.- 10.2 Statistical Treatment and the Transfer Function.- 10.3 Stable Isotopes.- 10.4 Distributional Pattern of Planktonic Foraminifera.- 10.4.1 Horizontal Distribution.- 10.4.2 Seasonal Distribution.- 10.4.3 Vertical Distribution.- 10.4.4 Patchiness and Daily Vertical Migration.- 10.4.5 General Sea Surface Temperature in the Past.- 10.5 Population Dynamics.- 10.5.1 Reproductive Strategies.- 10.5.1.1 Lunar Periodicity.- 10.5.1.2 Annual Periodicity.- 10.5.2 Water Mass Boundary Effects.- 10.6 Experimental Studies.- 10.7 Summary.- 11. Sedimentation - Settlement of Shells.- 11.1 Introduction.- 11.2 Shells Released by Reproduction and Juvenile Mortality.- 11.3 Aggregates - Sedimentation.- 11.4 Predation.- 11.5 Residence Time and Sinking Velocity.- 11.6 Seasonal Fluctuations in the Settlement.- 11.7 Dissolution in the Deep Water.- 11.8 Summary.- 12. Concluding Remarks.- 12.1 Effects Influencing the Isotopic Signal.- 12.1.1 Temperature Effect.- 12.1.2 GlacialEffect.- 12.1.3 Water Mass Effect.- 12.1.4 VitalEffect.- 12.1.5 Selective Production.- 12.1.6 Differential Dissolution.- 12.2 Carbon Isotopes.- 12.3 Summative Perspective.- 13. References.- 14. Glossary.- 15. Index.

Modern Planktonic Foraminifera

An improved and updated version of the statistical LOWESS fit to the marine 87Sr/86Sr record and a revised look-up table (V3:10/99; available from j.mcarthur@ucl.ac.uk) based upon it enables straightforward conversion of 87Sr/86Sr to numerical age, and vice versa, for use in strontium isotope stratigraphy (SIS). The table includes 95% confidence intervals on predictions of numerical age from 87Sr/86Sr. This version includes the Triassic and Paleozoic record (0509 Ma) omitted from previous versions because of the paucity of adequate data at the time of preparation. We highlight differences between the previous versions of the table and the current version and discuss some aspects of the 87Sr/86Sr record that may have geological significance. We give examples of how the table can be used and where it has proven useful.

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Strontium Isotope Stratigraphy: LOWESS Version 3: Best Fit to the Marine Sr‐Isotope Curve for 0–509 Ma and Accompanying Look‐up Table for Deriving Numerical Age

Oxygen isotope records and glaciomarine sediments indicate at least an intermittent presence of large continental ice sheets on Antarctica since the earliest Oligocene (circa 35 Ma). The growth and decay of ice sheets during the Oligocene to modern “ice house world” caused glacioeustatic sea level changes. The early Eocene was an ice-free “greenhouse world,” but it is not clear if ice sheets existed during the middle to late Eocene “doubt house world.” Benthic foraminiferal δ18O records place limits on the history of glaciation, suggesting the presence of ice sheets at least intermittently since the earliest Oligocene. The best indicator of ice growth is a coeval increase in global benthic and western equatorial planktonic δ18O records. Although planktonic isotope records from the western equatorial regions are limited, subtropical planktonic foraminifera may also record such ice volume changes. It is difficult to apply these established principles to the Cenozoic δ18O record because of the lack of adequate data and problems in stratigraphic correlations that obscure isotope events. We improved Oligocene to Miocene correlations of δ18O records and erected eight oxygen isotope zones (Oi1-Oi2, Mi1-Mi6). Benthic foraminiferal δ18O increases which are associated with the bases of Zones Oil (circa 35.8 Ma), Oi2 (circa 32.5 Ma), and Mil (circa 23.5 Ma) can be linked with δ18O increases in subtropical planktonic foraminifera and with intervals of glacial sedimentation on or near Antarctica. Our new correlations of middle Miocene benthic and western equatorial planktonic δ18O records show remarkable agreement in timing and amplitude. We interpret benthic-planktonic covariance to reflect substantial ice volume increases near the bases of Zones Mi2 (circa 16.1 Ma), Mi3 (circa 13.6 Ma), and possibly Mi5 (circa 11.3 Ma). Possible glacioeustatic lowerings are associated with the δ18O increases which culminated with the bases of Zone Mi4 (circa 12.6 Ma) and Mi6 (circa 9.6 Ma), although low-latitude planktonic δ18O records are required to test this. These inferred glacioeustatic lowerings can be linked to seismic and rock disconformities. For example, we link 12 Oligocene-early late Miocene inferred glacioeustatic lowerings with 12 of the sequence boundaries (= inferred eustatic lowerings) of Haq et al. (1987).

Unlocking the Ice House: Oligocene‐Miocene oxygen isotopes, eustasy, and margin erosion

The relation between the partial pressure of atmospheric carbon dioxide (pCO2) and Paleogene climate is poorly resolved. We used stable carbon isotopic values of di-unsaturated alkenones extracted from deep sea cores to reconstruct pCO2 from the middle Eocene to the late Oligocene (approximately 45 to 25 million years ago). Our results demonstrate that pCO2 ranged between 1000 to 1500 parts per million by volume in the middle to late Eocene, then decreased in several steps during the Oligocene, and reached modern levels by the latest Oligocene. The fall in pCO2 likely allowed for a critical expansion of ice sheets on Antarctica and promoted conditions that forced the onset of terrestrial C4 photosynthesis.

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Marked Decline in Atmospheric Carbon Dioxide Concentrations During the Paleogene

Climate models with increased levels of carbon dioxide predict that global warming causes heating in the tropics, but investigations of ancient climates based on palaeodata have generally indicated cool tropical temperatures during supposed greenhouse episodes. For example, in the Late Cretaceous and Eocene epochs there is abundant geological evidence for warm, mostly ice-free poles, but tropical sea surface temperatures are generally estimated to be only 15-23 degrees C, based on oxygen isotope palaeothermometry of surface-dwelling planktonic foraminifer shells. Here we question the validity of most such data on the grounds of poor preservation and diagenetic alteration. We present new data from exceptionally well preserved foraminifer shells extracted from impermeable clay-rich sediments, which indicate that for the intervals studied, tropical sea surface temperatures were at least 28-32 degrees C. These warm temperatures are more in line with our understanding of the geographical distributions of temperature-sensitive fossil organisms and the results of climate models with increased CO2 levels.

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Warm tropical sea surface temperatures in the Late Cretaceous and Eocene epochs

Olsson, Richard K., Christoph Hemleben, William A. Berggren, and Brian T. Huber, editors. Atlas of Paleocene Planktonic Foraminifera. Smithsonian Contributions to Paleobiology, number 85, 252 pages, 37 figures, 71 plates, 1999.—Sixty-seven species of Paleocene planktonic foraminifera are described and illustrated, including three species of Eoglobigerina, four species of Parasubbotina, five species of Subbotina, two species of Hedbergella, 10 species oiGlobanomalina, six species ofAcarinina, 12 species of Morozovella, three species of lgorina, four species of Praemurica, one species of Guembelitria, one species of Globoconusa, three species of Parvularugoglobigerina, two species of Woodringina, six species of Chiloguembelina, one species of Rectoguembelina, and four species of Zeauvigerina. Taxonomic classification of normal perforate taxa are organized according to wall texture. Spinose cancellate genera include Eoglobigerina, Parasubbotina, and Subbotina; cancellate nonspinose genera include Igorinina and Praemurica; smooth-walled genera include Hedbergella and Globanomalina; and muricate genera include Acarinina and Morozovella. Taxonomic classification of microperforate taxa (including Guembelitria, Globoconusa, Parvularugoglobigerina, Woodringina, Chiloguembelina, Rectoguembelina, and Zeauvigerina) are organized according to test morphology. Scanning electron microscope (SEM) images of type species described by Morozova in the collections of the Geological Institute, Academy of Sciences (GAN), Moscow, and the type material described by Subbotina in the collections of the All Union Petroleum Scientific Research Geological Prospecting Institute (VNIGRI), St. Petersburg, are shown on Plates 8-12. Twelve species described by Morozova, nine species described by Subbotina, and one species described by Bykova are illustrated. In addition, SEM images of 28 holotypes and two paratypes from the Smithsonian Institution collections are shown on Plates 13-17, and the lectotype for Globigerina compressa Plummer, 1926, and the neotype for Globorotalia monmouthensis Olsson, 1961, are designated and illustrated with SEM images. Paleobiogeographic maps showing the global distribution of 29 commonly occurring Paleocene taxa are included in the atlas, as well as figures showing the stratigraphic ranges of species by genus and stratigraphic first and last appearances. The biostratigraphic framework used in the atlas is the revised biostratigraphy given in Berggren et al., 1995, which is summarized in the atlas. Wall texture and morphological relationships between species and genera form the basis of phylogenetic interpretations. This is discussed in the section "Wall Texture, Classification, and Phylogeny" and is referenced to Plates 1-7. OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Annals of the Smithsonian Institution. SERIES COVER DESIGN: The trilobite Phacops rana Green. Library of Congress Cataloging-in-Publication Data Atlas of Paleocene planktonic foraminifera / Richard K. Olsson ... [et al.], editors. p. cm. — (Smithsonian contributions to paleobiology ; no. 85) Includes bibliographic references and index. 1. Foraminifera, Fossil. 2. Paleontology—Paleocene. I. Olsson, Richard K. II. Series. QE701.S56no.85 [QE772] 560s-dc21 [561'.994] 98-3474 ® The paper used in this publication meets the minimum requirements of the American National Standard for Permanence of Paper for Printed Library Materials Z39.48—1984.

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Atlas of Paleocene planktonic foraminifera

We provide a record of global sea-level (eustatic) variations of the Late Cretaceous (99- 65 Ma) greenhouse world. Ocean Drilling Program Leg 174AX provided a record of 11- 14 Upper Cretaceous sequences in the New Jersey Coastal Plain that were dated by in- tegrating Sr isotopic stratigraphy and biostratigraphy. Backstripping yielded a Late Cre- taceous eustatic estimate for these sequences, taking into account sediment loading, com- paction, paleowater depth, and basin subsidence. We show that Late Cretaceous sea-level changes were large (.25 m) and rapid (K1 m.y.), suggesting a glacioeustatic control. Three large d 18 O increases are linked to sequence boundaries (others lack sufficient d 18 O data), consistent with a glacioeustatic cause and with the development of small (,10 6 km 3 ) ephemeral ice sheets in Antarctica. Our sequence boundaries correlate with sea-level falls recorded by Exxon Production Research and sections from northwest Europe and Russia, indicating a global cause, although the Exxon record differs from backstripped estimates in amplitude and shape.

Late Cretaceous chronology of large, rapid sea-level changes: Glacioeustasy during the greenhouse world

Atlas of eocene planktonic foraminifera

We developed a Late Cretaceous sea- level estimate from Upper Cretaceous sequences at Bass River and Ancora, New Jersey (ODP [Ocean Drilling Program] Leg 174AX). We dated 11–14 sequences by integrating Sr isotope and biostratigraphy (age resolution ±0.5 m.y.) and then estimated paleoenvironmental changes within the sequences from lithofacies and biofacies analyses. Sequences generally shallow up-section from middle-neritic to inner-neritic paleodepths, as shown by the transition from thin basal glauconite shelf sands (transgressive systems tracts [TST]), to medial-prodelta silty clays (highstand systems tracts [HST]), and finally to upper–delta-front quartz sands (HST). Sea-level estimates obtained by backstripping (accounting for paleodepth variations, sediment loading, compaction, and basin subsidence) indicate that large (>25 m) and rapid (≪1 m.y.) sea-level variations occurred during the Late Cretaceous greenhouse world. The fact that the timing of Upper Cretaceous sequence boundaries in New Jersey is similar to the sea-level lowering records of Exxon Production Research Company (EPR), northwest European sections, and Russian platform outcrops points to a global cause. Because backstripping, seismicity, seismic stratigraphic data, and sediment-distribution patterns all indicate minimal tectonic effects on the New Jersey Coastal Plain, we interpret that we have isolated a eustatic signature. The only known mechanism that can explain such global changes— glacio-eustasy—is consistent with foraminiferal δ 18 O data. Either continental ice sheets paced sea-level changes during the Late Cretaceous, or our understanding of causal mechanisms for global sea-level change is fundamentally flawed. Comparison of our eustatic history with published ice-sheet models and Milankovitch predictions suggests that small (5–10 × 10 6 km 3 ), ephemeral, and areally restricted Antarctic ice sheets paced the Late Cretaceous global sea-level change. New Jersey and Russian eustatic estimates are typically one-half of the EPR amplitudes, though this difference varies through time, yielding markedly different eustatic curves. We conclude that New Jersey provides the best available estimate for Late Cretaceous sea-level variations.

Richard K. Olsson

Papers

Warm tropical sea surface temperatures in the Late Cretaceous and Eocene epochs

Atlas of Paleocene planktonic foraminifera

Late Cretaceous chronology of large, rapid sea-level changes: Glacioeustasy during the greenhouse world

Atlas of eocene planktonic foraminifera

Upper Cretaceous sequences and sea-level history, New Jersey Coastal Plain