Delayed recovery and the spacing of major extinctions

Paleobiology ◽  
1990 ◽  
Vol 16 (4) ◽  
pp. 401-414 ◽  
Author(s):  
Steven M. Stanley
Keyword(s):  
Environmental Conditions ◽  
Marine Invertebrate ◽  
Planktonic Foraminifera ◽  
Late Eocene ◽  
Western Atlantic ◽  
General Hypothesis ◽  
The Past ◽  
Early Oligocene ◽  
Late Neogene ◽  
Delayed Recovery

Approximate periodicity for peak rates of global extinction during the past 250 m.y. may have resulted from delayed recovery following major extinction events. Two components can be envisioned for such delays: persistence of inimical environmental conditions for some time after the onset of the crisis, and slow restoration of vulnerable taxa. This general hypothesis is consistent with statistical evidence of linkage between measured rates of extinction of marine invertebrate genera for contiguous stages and substages of the geologic column. The nine broad valleys between the “periodic” peak rates for the past 250 m.y. exhibit only three trivial secondary peaks, indicating that, if the pattern is not artifactual, trends in global rates of extinction have not readily been abruptly reversed. Moreover, the smooth observed trends reflect the fact that regional crises tend to remove many species but few genera. To some degree, high rates of extinction that precede peak rates must represent bias of the incomplete fossil record (the Signor-Lipps effect). High rates that immediately follow peak rates also may, to a degree, reflect biological legacy: (1) final extinction of weakened genera or (2) extinction of new genera that contain few species or represent failed evolutionary “experiments.” Nonetheless, there is evidence that protracted intervals of stressful environmental conditions contributed to high rates of extinction preceding or following certain peak intervals, including the Scythian, Cenomanian, Early Paleocene, and Early Oligocene. The reef-building rudists, for example, suffered heavy extinction during both Cenomanian and Turonian time and then failed to recover quickly.The late Neogene record of bivalve molluscs in the Western Atlantic offers a more detailed picture of delayed recovery. Here early intervals of glacial expansion caused heavy extinction, leaving an impoverished, eurythermal fauna that was virtually unaffected by late Pleistocene glacial episodes. The episode of heavy extinction in Late Eocene time exhibits a similar phenomenon on a worldwide scale. Among the planktonic foraminifera, warm-adapted stenothermal species died out, and eurythermal forms predominated throughout Oligocene time; restoration of vulnerable, stenothermal species proceeded gradually during the Miocene Epoch. This example of delayed recovery and others like it following earlier global crises may have prevented such crises from following one another in rapid succession, yielding an appearance of periodicity.

scholarly journals Planktonic foraminiferal biostratigraphy and lithology of the Upper Cretaceous (upper Campanian-Maastrichtian) and Palaeogene succession of the Palmyrides (Syria)

2021 ◽  
Vol 74 (1) ◽  
pp. 21-40
Author(s):  
Vlasta Premec-Fućek ◽  
Morana Hernitz Kučenjak ◽  
Gabrijela Pecimotika ◽  
◽  
Keyword(s):  
Middle Eocene ◽  
Planktonic Foraminifera ◽  
Age Determination ◽  
Late Eocene ◽  
Warm Water ◽  
Subtropical Climate ◽  
Foraminiferal Assemblage ◽  
Climate Conditions ◽  
Early Oligocene ◽  
Upper Campanian

An upper Campanian to upper Oligocene stratigraphic succession has been examined from six deep exploration wells in the Palmyrides area of Syria. Most of the sedimentary succession contains rich and well to moderately preserved planktonic foraminiferal assemblages that enable successful age determination. The upper Campanian and Maastrichtian planktonic fauna is highly diverse with domination of warm water taxa such as Globotruncana aegyptiaca, Gansserina gansseri, Globotruncanella havanensis, Globotruncanita angulata and Pseudotextularia elegans. The most dramatic turnover occurred across the Cretaceous/Palaeocene boundary when most planktonic foraminiferal species became extinct. The oldest Palaeocene planktonic foraminiferal assemblage, rich in the number of specimens, but not very diverse, includes the following species: Eoglobigerina eobulloides, Globanomalina archeocompressa, Chiloguembelina morsei, Woodringina claytonensis and Parasubbotina pseudobulloides. The late Palaeocene is marked by origination of the morozovellids, acarininids and globanomalinids, while the early Eocene is characterized by a tropical assemblage, dominated by muricate species, and by intensive speciation of Acarinina and Subbotina in the latest part. Most of these species continue into the middle Eocene and become a significant component of the planktonic community. The middle Eocene is characterized by intensive speciation and domination of warm water genera such as Acarinina, Morozovelloides, and to a lesser degree Turborotalia, Globigerinatheka and Hantkenina. The middle/late Eocene boundary is marked by double extinction of the last muricate taxa Acarinina mcgowrani and Morozovelloides crasssatus, which indicate a variable climate, water column instability, and loss of surface habitats. In contrast, Turborotalia and Globigerinateheka become more important in the late Eocene. The Eocene/Oligocene boundary is marked by the extinction of most warm water taxa including Turborotalia cerroazulensis group, Hantkenina, Globigerinatheka and some subbotinids. The beginning of the early Oligocene is indicated by the domination of cool water taxa such as Dentoglobigerina, Globorotaloides, Tenuitella and Chiloguembelina. Speciation of the spinose surface dweller Ciperoella ciperoensis group reflects warming in the late Oligocene. The combined observations of lithology with the diversity and composition of planktonic foraminifera assemblages indicate that the Palmyrides area in Syria was a Tethyan bioprovince with a tropical to subtropical climate from the late Campanian to the end of the Eocene with deposition in deep sea environments (upper bathyal to outer shelf). In contrast, Oligocene deposits and their microfossil content suggest temperate to warm climate conditions and sedimentation in middle to inner shelf environments.

scholarly journals Late Neogene evolution of modern deep-dwelling plankton

2021 ◽  
Author(s):  
Flavia Boscolo-Galazzo ◽  
Amy Jones ◽  
Tom Dunkley Jones ◽  
Katherine A. Crichton ◽  
Bridget S. Wade ◽  
...  
Keyword(s):  
Water Column ◽  
Deep Water ◽  
Middle Miocene ◽  
Planktonic Foraminifera ◽  
Euphotic Zone ◽  
Biological Pump ◽  
Calcareous Nannofossils ◽  
The Past ◽  
Late Neogene ◽  
Global Cooling

Abstract. The fossil record of marine microplankton provides insights into the evolutionary drivers which led to the origin of modern deep-water plankton, one of the largest component of ocean biomass. We use global abundance and biogeographic data combined with depth habitat reconstructions to determine the environmental mechanisms behind speciation in two groups of pelagic microfossils over the past 15 million years. We compare our microfossil datasets with water column profiles simulated in an Earth System model. We show that deep-living planktonic foraminiferal (zooplankton) and calcareous nannofossil (mixotroph phytoplankton) species were virtually absent globally during the peak of the middle Miocene warmth. Evolution of deep-dwelling planktonic foraminifera started from subpolar-midlatitude species during late Miocene cooling, via allopatry. Deep-dwelling species subsequently spread towards lower latitudes and further diversified via depth sympatry, establishing modern communities stratified hundreds of meters down the water column. Similarly, sub-euphotic zone specialist calcareous nannofossils become a major component of tropical and sub-tropical assemblages through the latest Miocene to early Pliocene. Our model simulations suggest that increased organic matter and oxygen availability for planktonic foraminifera, and increased nutrients and light penetration for nannoplankton, favored the evolution of new deep water niches. These conditions resulted from global cooling and the associated increase in the efficiency of the biological pump over the last 15 million years.

West Antarctic archipelago covered by cool-temperate forests during early Oligocene glaciation

2021 ◽  
Author(s):  
Johann Philipp Klages ◽  
Claus-Dieter Hillenbrand ◽  
Steven M. Bohaty ◽  
Ulrich Salzmann ◽  
Torsten Bickert ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Late Eocene ◽  
Major Step ◽  
Amundsen Sea ◽  
West Antarctic Ice Sheet ◽  
Shallow Marine ◽  
West Antarctic ◽  
Early Oligocene ◽  
Late Neogene ◽  
Cool Temperate

<p>The Eocene-Oligocene Transition (~34.4–33.7 Ma) marks a major step in the long-term evolution from the greenhouse climate of the Early Palaeogene to the icehouse regime of the Late Neogene and Quaternary. However, it remains uncertain which landmasses were covered by ice sheets during the Early Oligocene Glacial Maximum (~33.7–33.2 Ma), an interval of peak glaciation inferred from deep-sea benthic foraminifera oxygen isotope records that immediately follows the Eocene-Oligocene Transition. The scarcity of Late Eocene and Early Oligocene continental and shallow-marine records in both Arctic and Antarctic regions has prevented the reconstruction of environmental conditions and ice-sheet extent during the Early Oligocene, which is critical for assessing ice–ocean–atmosphere interactions during early stages of the Cenozoic icehouse. Here, we present the first Early Oligocene shallow-marine record from the Pacific margin of West Antarctica, recovered from the central Amundsen Sea Embayment shelf on RV <em>Polarstern</em> expedition PS104 at Site 21. Marine mudstones recovered at this site document the presence of a vegetated archipelago at a palaeo-latitude of 73.5°S. Pollen assemblages and organic biomarker proxies indicate a cool-temperate <em>Nothofagus</em>-dominated forest situated within a productive marine archipelago. No evidence for marine terminating ice was detected in the cores from Site 21, thus indicating that the West Antarctic Ice Sheet was small or entirely absent during the Early Oligocene.</p>

Developments in sugarcane processing over the past 15 years

2019 ◽  
pp. 451-458
Author(s):  
Peter W. Rein
Keyword(s):  
Environmental Conditions ◽  
Energy Value ◽  
The Past ◽  
Recent Developments ◽  
Technology Of Production ◽  
Sugarcane Processing

Developments in the technology of production of sugar from sugarcane tend to be incremental improvements in an effort to reduce costs and boost revenue. Nonetheless the developments are significant and contribute to sustainable sugarcane enterprises. Some technologies have adapted to changing environmental conditions, and more attention is being given to boosting revenue through associated activities, particularly in enhancing the potential for sugarcane operations to exploit the energy value of sugarcane. This paper outlines recent developments of interest in processing sugarcane.

Falcatifolium (Podocarpaceae) macrofossils from paleogene sediments in south-eastern Australia: a reassessment

1998 ◽  
Vol 11 (6) ◽  
pp. 711 ◽  
Author(s):  
Robert S. Hill ◽  
Leonie J. Scriven
Keyword(s):  
Leaf Morphology ◽  
Middle Eocene ◽  
Late Eocene ◽  
South Eastern ◽  
Early Oligocene ◽  
Extant Species ◽  
Eastern Australia ◽  
South Eastern Australia

A re-investigation of macrofossils previously referred to the extantpodocarpaceous genus Falcatifolium Laubenfels shows thatno records can be sustained. Falcatifolium australisD.R.Greenwood from Middle Eocene sediments in Victoria bears littleresemblance to extant species in the genus and is transferred to the newfossil genus Sigmaphyllum R.S.Hill & L.J.Scriven.Specimens from Early Oligocene sediments in Tasmania previously assigned toFalcatifolium are described as a second species ofSigmaphyllum, S. tasmanensisR.S.Hill & L.J.Scriven, and specimens from mid to late Eocene sediments inTasmania previously assigned to Falcatifolium do notbelong to that genus, although their true generic affinities are uncertain.Dispersed cuticle specimens from Late Eocene–Oligocene sediments inSouth Australia referred to Falcatifolium are notreliable records of the genus and require further investigation. However,Dacrycarpus eocenica D.R.Greenwood, from Middle Eocenesediments in Victoria is transferred to Falcatifolium,and is similar to the extant species F. angustumLaubenfels, which has a leaf morphology unusual for the genus.Falcatifolium eocenica (D.R.Greenwood) R.S.Hill & L.J.Scriven is the only reliable record of the genus in the Australian fossilrecord to date.

The Upper Cretaceous foraminiferal record of IODP Site U1512 (Great Australian Bight, Indian Ocean)

2021 ◽  
Author(s):  
Erik Wolfgring ◽  
Michael A. Kaminski ◽  
Anna Waśkowska ◽  
Maria Rose Petrizzo ◽  
Eun Young Lee ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Ocean Circulation ◽  
Planktonic Foraminifera ◽  
Late Eocene ◽  
Foraminiferal Assemblage ◽  
Benthic Foraminiferal Assemblage ◽  
International Ocean Discovery Program ◽  
Foraminiferal Record ◽  
Great Australian Bight ◽  
Microfossil Assemblage

<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>

scholarly journals Quantifying sea surface temperature ranges of the Arabian Sea for the past 20 000 years

2011 ◽  
Vol 7 (4) ◽  
pp. 1337-1349 ◽  
Author(s):  
G. M. Ganssen ◽  
F. J. C. Peeters ◽  
B. Metcalfe ◽  
P. Anand ◽  
S. J. A. Jung ◽  
...  
Keyword(s):  
Arabian Sea ◽  
Isotope Composition ◽  
Planktonic Foraminifera ◽  
Sediment Cores ◽  
Maximum Temperature ◽  
Physical Parameters ◽  
Seasonal Temperature ◽  
Mean Values ◽  
The Past ◽  
Temperature Ranges

Abstract. The oxygen isotopic composition of planktonic foraminifera tests is one of the widest used geochemical tools to reconstruct past changes of physical parameters of the upper ocean. It is common practice to analyze multiple individuals from a mono-specific population and assume that the outcome reflects a mean value of the environmental conditions during calcification of the analyzed individuals. Here we present the oxygen isotope composition of individual specimens of the surface-dwelling species Globigerinoides ruber and Globigerina bulloides from sediment cores in the Western Arabian Sea off Somalia, inferred as indicators of past seasonal ranges in temperature. Combining the δ18O measurements of individual specimens to obtain temperature ranges with Mg/Ca based mean calcification temperatures allows us to reconstruct temperature extrema. Our results indicate that over the past 20 kyr the seasonal temperature range has fluctuated from its present value of 16 °C to mean values of 13 °C and 11 °C for the Holocene and LGM, respectively. The data for the LGM suggest that the maximum temperature was lower, whilst minimum temperature remained approximately constant. The rather minor variability in lowest summer temperatures during the LGM suggests roughly constant summer monsoon intensity, while upwelling-induced productivity was lowered.

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