Stratigraphic and sedimentological aspects of the worldwide distribution of Apectodinium in Paleocene/Eocene Thermal Maximum deposits

2021 ◽  
pp. SP511-2020-46
Author(s):  
Christopher N. Denison
Keyword(s):  
Global Warming ◽  
Sea Level ◽  
Environmental Changes ◽  
Calcareous Nannofossil ◽  
Shallow Marine ◽  
Worldwide Distribution ◽  
Carbon Isotope Excursion ◽  
Thermal Maximum ◽  
Taxonomic Changes ◽  
Data Gap

AbstractThe Paleocene/Eocene Thermal Maximum (PETM) is characterized by pronounced global warming and associated environmental changes. In the more-or-less two decades since prior regional syntheses of Apectodinium distribution at the PETM, extensive biological and geochemical datasets have elucidated the effect of rising world temperatures on climate and the biome. A Carbon Isotope Excursion (CIE) that marks the Paleocene/Eocene Boundary (PEB) is associated with an acme of marine dinocysts of the genus Apectodinium in many locations. Distinctive foraminiferal and calcareous nannofossil populations may also be present.For this up-dated, dinocyst-oriented view of the PETM, data from worldwide locations have been evaluated with an emphasis on stratigraphic and sedimentological context. What has emerged is that a change in lithology is common, often to a distinctive siltstone or claystone unit, which contrasts with underlying and overlying lithotypes. This change, present in shallow marine/coastal settings and in deepwater turbidite deposits, is attributed to radical modifications of precipitation and erosional processes. An abrupt boundary carries the implication that some time (of unknowable duration) is potentially missing, which then requires caution in the interpretation of the pacing of events in relation to that boundary. In most instances an ‘abrupt’ or ‘rapid’ CIE onset can be attributed to a data gap at a hiatus, particularly in shallow shelf settings where transgression resulted from sea-level rise associated with the PETM. Truly gradational lower boundaries of the PETM interval are quite unusual, and if present, are poorly known so far. Gradational upper boundaries are more common, but erosional upper boundaries have been reported.Taxonomic changes have been made to clarify identification issues that have adversely impacted some biostratigraphic interpretations. Apectodinium hyperacanthum has been retained in Wetzeliella, its original genus. The majority of specimens previously assigned to Apectodinium hyperacanthum or Wetzeliella (Apectodinium) hyperacanthum have been re-assigned to an informal species, Apectodinium sp. 1. Dracodinium astra has been retained in its original genus as Wetzeliella astra, and is emended.

scholarly journals Salinity changes and anoxia resulting from enhanced run-off during the late Permian global warming and mass extinction event

2018 ◽  
Vol 14 (4) ◽  
pp. 441-453 ◽  
Author(s):  
Elsbeth E. van Soelen ◽  
Richard J. Twitchett ◽  
Wolfram M. Kürschner
Keyword(s):  
Global Warming ◽  
Soil Erosion ◽  
Environmental Changes ◽  
Hydrological Cycle ◽  
Seawater Temperature ◽  
Late Permian ◽  
Terrestrial Environment ◽  
Shallow Marine ◽  
Run Off ◽  
Extinction Event

Abstract. The late Permian biotic crisis had a major impact on marine and terrestrial environments. Rising CO2 levels following Siberian Trap volcanic activity were likely responsible for expanding marine anoxia and elevated water temperatures. This study focuses on one of the stratigraphically most expanded Permian–Triassic records known, from Jameson Land, East Greenland. High-resolution sampling allows for a detailed reconstruction of the changing environmental conditions during the extinction event and the development of anoxic water conditions. Since very little is known about how salinity was affected during the extinction event, we especially focus on the aquatic palynomorphs and infer changes in salinity from changes in the assemblage and morphology. The start of the extinction event, here defined by a peak in spore : pollen, indicating disturbance and vegetation destruction in the terrestrial environment, postdates a negative excursion in the total organic carbon, but predates the development of anoxia in the basin. Based on the newest estimations for sedimentation rates, the marine and terrestrial ecosystem collapse took between 1.6 and 8 kyr, a much shorter interval than previously estimated. The palynofacies and palynomorph records show that the environmental changes can be explained by enhanced run-off and increased primary productivity and water column stratification. A lowering in salinity is supported by changes in the acritarch morphology. The length of the processes of the acritarchs becomes shorter during the extinction event and we propose that these changes are evidence for a reduction in salinity in the shallow marine setting of the study site. This inference is supported by changes in acritarch distribution, which suggest a change in palaeoenvironment from open marine conditions before the start of the extinction event to more nearshore conditions during and after the crisis. In a period of sea-level rise, such a reduction in salinity can only be explained by increased run-off. High amounts of both terrestrial and marine organic fragments in the first anoxic layers suggest that high run-off, increased nutrient availability, possibly in combination with soil erosion, are responsible for the development of anoxia in the basin. Enhanced run-off could result from changes in the hydrological cycle during the late Permian extinction event, which is a likely consequence of global warming. In addition, vegetation destruction and soil erosion may also have resulted in enhanced run-off. Salinity stratification could potentially explain the development of anoxia in other shallow marine sites. The input of freshwater and related changes in coastal salinity could also have implications for the interpretation of oxygen isotope records and seawater temperature reconstructions at some sites.

scholarly journals The Toarcian Oceanic Anoxic Event: where do we stand?

2021 ◽  
pp. SP514-2021-74
Author(s):  
Matías Reolid ◽  
Emanuela Mattioli ◽  
Luís V. Duarte ◽  
Wolfgang Ruebsam
Keyword(s):  
Global Warming ◽  
Carbon Cycle ◽  
Sea Level ◽  
Climate Changes ◽  
Environmental Changes ◽  
Global Changes ◽  
Ecosystem Responses ◽  
Oceanic Anoxic Event ◽  
Anoxic Event ◽  
Collateral Effects

AbstractThe study of past climate changes is pivotal for understanding the complex biogeochemical interactions through time between the geosphere, atmosphere, hydrosphere and biosphere, which are critical for predicting future global changes. The Toarcian Oceanic Anoxic Event, also known as the Jenkyns Event, was a hyperthermal episode which occurred during the early Toarcian (∼183 Ma; Early Jurassic) and resulted in numerous collateral effects including global warming, enhanced weathering, sea-level change, carbonate crisis, marine anoxia-dysoxia, and biotic crisis. The IGCP-655 project of the IUGS-UNESCO has constituted an international network of researchers with different disciplinary skills who collaborated and shared conceptual advances on uncovering drivers of the environmental changes and ecosystem responses. This volume, Carbon Cycle and Ecosystem Response to the Jenkyns Event in the Early Toarcian (Jurassic), presents 16 works that investigate the early Toarcian environmental changes related to the global warming, sea-level rise, carbon cycle perturbation and second-order mass extinction through biostratigraphy, micropalaeontology, palaeontology, ichnology, palaeoecology, sedimentology, integrated stratigraphy, inorganic, organic and isotopic geochemistry, and cyclostratigraphy.

scholarly journals Benthic Foraminifera and Geochemistry Across the Paleocene–eocene Thermal Maximum Interval in Jordan

2018 ◽  
Vol 48 (2) ◽  
pp. 100-120 ◽  
Author(s):  
Victor M. Giraldo-Gómez ◽  
Jörg Mutterlose ◽  
Olaf G. Podlaha ◽  
Robert P. Speijer ◽  
Peter Stassen
Keyword(s):  
Benthic Foraminifera ◽  
Oxygen Deficiency ◽  
Organic Content ◽  
Calcareous Nannofossil ◽  
Carbon Isotope Excursion ◽  
Thermal Maximum ◽  
Proximal Site ◽  
Oxygen Conditions ◽  
Bottom Waters ◽  
Distal Site

AbstractThis study presents benthic foraminiferal data from two sedimentary successions across the Paleocene–Eocene Thermal Maximum (PETM) from Jordan. Calcareous nannofossil biozones NP9a, NP9b, and NP10 of latest Paleocene and earliest Eocene age were encountered in proximal (core OS–01) and distal (core OS–28) sites. Lithologically, the investigated sequence consists of marls, shales, and limestones attributed to the Muwaqqar Chalk-Marl Formation and the Um Rijam Chert Limestone Formation. The δ13Corg curve records the typical carbon isotope excursion (CIE) and shows four distinctive intervals (pre-CIE, CIE-“core”, CIE-“recovery”, post-CIE) over the entire PETM interval in both cores.In the pre-CIE interval, the more proximal site (OS–01) shows high abundances of Neoeponides duwi co-occurring with an outer neritic Midway-type fauna. The fauna indicates meso- to eutrophic conditions in a middle- to outer-neritic setting. The more distal site (OS–28) is characterized by outer-neritic to upper-bathyal taxa (e.g., Cibicides pseudoacutus, Gavelinella beccariiformis, Nuttallides truempyi) suggesting well-ventilated, oligo- to mesotrophic seafloor conditions.The earliest Eocene corresponds to the CIE-“core” interval and is marked by a negative δ13Corg signal, high TOC, low CaCO3 contents, and near absence of benthic foraminifera. Oxygen deficiency in bottom waters with increased organic flux is the most likely scenario to explain the elevated organic content at the seafloor.The subsequent CIE-“recovery” interval of early Eocene age is marked by a restoration of oxygenated seafloor conditions. The proximal site is characterized by a relatively elevated TOC content and high abundance of Lenticulina spp., Valvulineria scrobiculata and common Anomalinoides zitteli, suggesting moderate oxygen conditions and mesotrophic bottom waters. The distal site is characterized by low TOC content and the presence of Lenticulina spp., Valvulineria scrobiculata, Anomalinoides zitteli and Oridorsalis plummerae, indicating a normalization of the organic flux and moderate oxygen concentrations near the seafloor.The post-CIE interval is marked by low TOC content in both cores. Benthic foraminifera include abundant Anomalinoides zitteli and common Lenticulina spp., Valvulineria scrobiculata, Oridorsalis plummerae, Cibicidoides rigidus, Cibicidoides pharaonis, and Anomalinoides praeacutus in the proximal setting. Mesotrophic conditions and a better ventilation of bottom waters are suggested for this interval. Lenticulina spp., Valvulineria scrobiculata, and Oridorsalis plummerae are also associated with the post-CIE interval in the distal site, suggesting similar mesotrophic conditions with renewed oxygenation in bottom waters.

scholarly journals A multi-proxy record of the Latest Danian Event at Gebel Qreiya, Eastern Desert, Egypt

2011 ◽  
Vol 30 (2) ◽  
pp. 167-182 ◽  
Author(s):  
J. Sprong ◽  
M. A. Youssef ◽  
A. Bornemann ◽  
P. Schulte ◽  
E. Steurbaut ◽  
...  
Keyword(s):  
Sea Level ◽  
Benthic Foraminifera ◽  
Environmental Changes ◽  
Eastern Desert ◽  
Trace Element Geochemistry ◽  
Calcareous Nannofossils ◽  
Element Geochemistry ◽  
Sea Level Fluctuations ◽  
Sequence Of Events ◽  
Carbon Isotope Excursion

Abstract. The Latest Danian Event (LDE) is a proposed early Palaeogene transient warming event similar to the Paleocene–Eocene Thermal Maximum, albeit of smaller magnitude. The LDE can be correlated with a carbon isotope excursion (‘CIE-DS1’) at Zumaia, Spain, and the ‘top Chron C27n event’ defined recently from ocean drilling sites in the Atlantic and Pacific, supporting a global extent. Yet, records of environmental change during the LDE (e.g. warming and sea-level fluctuations) are still rare. In this study, we focus on the micropalaeontology (calcareous nannofossils and benthic foraminifera), mineralogy and trace element geochemistry of the LDE in the Qreiya 3 section from the southern Tethyan margin in Egypt. In this section, the LDE is characterized by the occurrence of anomalous beds intercalated within upper Danian shales and marls. The event beds of the LDE are situated above an unconformity on top of a shallowing-upwards sequence deposited in a well-oxygenated outer neritic to upper bathyal marine palaeoenvironment. The lower LDE bed is barren of benthic foraminifera, but contains pyrite and fish remains, and is interpreted as an anoxic level formed during rapid relative sea-level rise. Incursion of a Neoeponides duwi (Nakkady, 1950) benthic assemblage in LDE bed II is interpreted as repopulation of the seafloor after anoxia. The sea-level cycle associated with the LDE is estimated at about 50 m maximum in the Qreiya 3 section. The environmental changes at Qreiya 3 are of supra-regional extent, since a similar sequence of events has been observed at other southern Tethyan locations.

scholarly journals Warming, euxinia and sea level rise during the Paleocene–Eocene Thermal Maximum on the Gulf Coastal Plain: implications for ocean oxygenation and nutrient cycling

2014 ◽  
Vol 10 (4) ◽  
pp. 1421-1439 ◽  
Author(s):  
A. Sluijs ◽  
L. van Roij ◽  
G. J. Harrington ◽  
S. Schouten ◽  
J. A. Sessa ◽  
...  
Keyword(s):  
Global Warming ◽  
Nutrient Cycling ◽  
Sea Level Rise ◽  
Sea Level ◽  
Coastal Plain ◽  
Continental Margins ◽  
Gulf Coastal Plain ◽  
Thermal Maximum ◽  
Organic Carbon Burial ◽  
Phosphorus Regeneration

Abstract. The Paleocene–Eocene Thermal Maximum (PETM, ~ 56 Ma) was a ~ 200 kyr episode of global warming, associated with massive injections of 13C-depleted carbon into the ocean–atmosphere system. Although climate change during the PETM is relatively well constrained, effects on marine oxygen concentrations and nutrient cycling remain largely unclear. We identify the PETM in a sediment core from the US margin of the Gulf of Mexico. Biomarker-based paleotemperature proxies (methylation of branched tetraether–cyclization of branched tetraether (MBT–CBT) and TEX86) indicate that continental air and sea surface temperatures warmed from 27–29 to ~ 35 °C, although variations in the relative abundances of terrestrial and marine biomarkers may have influenced these estimates. Vegetation changes, as recorded from pollen assemblages, support this warming. The PETM is bracketed by two unconformities. It overlies Paleocene silt- and mudstones and is rich in angular (thus in situ produced; autochthonous) glauconite grains, which indicate sedimentary condensation. A drop in the relative abundance of terrestrial organic matter and changes in the dinoflagellate cyst assemblages suggest that rising sea level shifted the deposition of terrigenous material landward. This is consistent with previous findings of eustatic sea level rise during the PETM. Regionally, the attribution of the glauconite-rich unit to the PETM implicates the dating of a primate fossil, argued to represent the oldest North American specimen on record. The biomarker isorenieratene within the PETM indicates that euxinic photic zone conditions developed, likely seasonally, along the Gulf Coastal Plain. A global data compilation indicates that O2 concentrations dropped in all ocean basins in response to warming, hydrological change, and carbon cycle feedbacks. This culminated in (seasonal) anoxia along many continental margins, analogous to modern trends. Seafloor deoxygenation and widespread (seasonal) anoxia likely caused phosphorus regeneration from suboxic and anoxic sediments. We argue that this fueled shelf eutrophication, as widely recorded from microfossil studies, increasing organic carbon burial along many continental margins as a negative feedback to carbon input and global warming. If properly quantified with future work, the PETM offers the opportunity to assess the biogeochemical effects of enhanced phosphorus regeneration, as well as the timescales on which this feedback operates in view of modern and future ocean deoxygenation.

scholarly journals Salinity changes and anoxia resulting from enhanced runoff during the late Permian global warming and mass extinction event

2017 ◽  
Author(s):  
Elsbeth E. van Soelen ◽  
Richard J. Twitchett ◽  
Wolfram M. Kürschner
Keyword(s):  
Global Warming ◽  
Soil Erosion ◽  
Environmental Changes ◽  
Sea Water ◽  
Hydrological Cycle ◽  
Terrestrial Ecosystem ◽  
Late Permian ◽  
Terrestrial Environment ◽  
Shallow Marine ◽  
Extinction Event

Abstract. The Late Permian biotic crisis had a major impact on marine and terrestrial environments. Rising CO2 levels following Siberian Trap volcanic activity were likely responsible for expanding marine anoxia and elevated water temperatures. This study focusses on one of the stratigraphically most expanded Permian-Triassic records known, from Jameson land, east Greenland. High resolution sampling allows for a detailed reconstruction of the changing environmental conditions during the extinction event and the development of anoxic water conditions. Since very little is known about how salinity was affected during the extinction event, we especially focus on the aquatic palynomorphs and infer changes in salinity from changes in the assemblage and morphology. The extinction event, here defined by a peak in spore/pollen, indicating disturbance and vegetation destruction in the terrestrial environment, postdates a negative excursion in the total organic carbon, but predates the development of anoxia in the basin. Based on the newest estimations for sedimentation rates, the marine and terrestrial ecosystem collapse took between 1.6 to 8 kyrs, a much shorter interval than previously estimated. The palynofacies and palynomorph records show that the environmental changes can be explained by enhanced runoff, increased primary productivity and water column stratification. A lowering in salinity is supported by changes in the acritarch morphology. The length of the processes of the acritarchs becomes shorter during the extinction event and we propose that these changes are evidence for a reduction in salinity in the shallow marine setting of the study site. This inference is supported by changes in acritarch distribution, which suggest a change in palaeoenvironment from open marine conditions before the start of the extinction event to more near-shore conditions during and after the crisis. In a period of sea-level rise, such a reduction in salinity can only be explained by increased runoff. High amounts of both terrestrial and marine organic fragments in the first anoxic layers suggest that high runoff, increased nutrient availability, possibly in combination with soil erosion, are responsible for the development of anoxia in the basin. Enhanced runoff could result from changes in the hydrological cycle during the late Permian extinction event, which is a likely consequence of global warming. In addition, vegetation destruction and soil erosion may also have resulted in enhanced runoff. Salinity stratification could potentially explain the development of anoxia in other shallow marine sites. The input of fresh water and related changes in coastal salinity could also have implications for the interpretation of oxygen isotope records and sea water temperature reconstructions in some sites.

scholarly journals Extreme warming, photic zone euxinia and sea level rise during the Paleocene/Eocene Thermal Maximum on the Gulf of Mexico Coastal Plain; connecting marginal marine biotic signals, nutrient cycling and ocean deoxygenation

2013 ◽  
Vol 9 (6) ◽  
pp. 6459-6494 ◽  
Author(s):  
A. Sluijs ◽  
L. van Roij ◽  
G. J. Harrington ◽  
S. Schouten ◽  
J. A. Sessa ◽  
...  
Keyword(s):  
Global Warming ◽  
Nutrient Cycling ◽  
Gulf Of Mexico ◽  
Sea Level Rise ◽  
Sea Level ◽  
Continental Margins ◽  
Photic Zone ◽  
Thermal Maximum ◽  
Phosphorus Regeneration ◽  
Relative Abundances

Abstract. The Paleocene/Eocene Thermal Maximum (PETM, ~56 Ma) was a ~200 kyr episode of global warming, associated with massive injections of 13C-depleted carbon into the ocean-atmosphere system. Although climate change during the PETM is relatively well constrained, effects on marine oxygen and nutrient cycling remain largely unclear. We identify the PETM in a sediment core from the US margin of the Gulf of Mexico. Biomarker-based paleotemperature proxies (MBT/CBT and TEX86) indicate that continental air and sea surface temperatures warmed from 27–29 °C to ~35 °C, although variations in the relative abundances of terrestrial and marine biomarkers may have influenced the record. Vegetation changes as recorded from pollen assemblages supports profound warming. Lithology, relative abundances of terrestrial vs. marine palynomorphs as well as dinoflagellate cyst and biomarker assemblages indicate sea level rise during the PETM, consistent with previously recognized eustatic rise. The recognition of a maximum flooding surface during the PETM changes regional sequence stratigraphic interpretations, which allows us to exclude the previously posed hypothesis that a nearby fossil found in PETM-deposits represents the first North American primate. Within the PETM we record the biomarker isorenieratane, diagnostic of euxinic photic zone conditions. A global data compilation indicates that deoxygenation occurred in large regions of the global ocean in response to warming, hydrological change, and carbon cycle feedbacks, particularly along continental margins, analogous to modern trends. Seafloor deoxygenation and widespread anoxia likely caused phosphorus regeneration from suboxic and anoxic sediments. We argue that this fuelled shelf eutrophication, as widely recorded from microfossil studies, increasing organic carbon burial along continental margins as a negative feedback to carbon input and global warming. If properly quantified with future work, the PETM offers the opportunity to assess the biogeochemical effects of enhanced phosphorus regeneration, as well as the time-scales on which this feedback operates in view of modern and future ocean deoxygenation.

Resilience of SW Pacific marine plankton to Cenozoic global warming events

2021 ◽  
Author(s):  
Chris Hollis ◽  
Giuseppe Cortese ◽  
Martin Crundwell ◽  
Claire Shepherd ◽  
Erica Crouch ◽  
...  
Keyword(s):  
Global Warming ◽  
Environmental Changes ◽  
Middle Eocene ◽  
Marine Plankton ◽  
Last Interglacial ◽  
Deep Sea Sediment ◽  
Sw Pacific ◽  
Thermal Maximum ◽  
Future Global Warming ◽  
Plankton Communities

<p>Ceonozoic deep-sea sediment archives from the southwest Pacific have been used to reconstruct regional climatic and environmental changes associated with global warming events from the earliest Eocene to the Last Interglacial. Less attention has been given to the biotic significance of associated changes in microfossil assemblages. Here we report what is currently known of the effects that global warming events have had on regional plankton communities, specifically foraminifera, calcareous nannoplankton, radiolarians and dinoflagellates. We focus on a succession of events representative of different magnitudes of global warming, including the Paleocene-Eocene thermal maximum, early and middle Eocene climatic optima, middle Miocene climatic optimum, mid-Pliocene warm period, and the Last Interglacial. From this study, we hope to establish ways in which the fossil record can be applied to assess the resilience of modern marine plankton communities to current and future global warming.</p>

scholarly journals Deciphering the Palaeocene–Eocene thermal maximum by Granger causality test

2021 ◽  
Author(s):  
Zeyang Liu ◽  
Xiehua Ji ◽  
Wenyan Luo ◽  
Yujie Hu ◽  
Haoran Liu
Keyword(s):  
Global Warming ◽  
Carbon Emission ◽  
Causality Test ◽  
Environmental Perturbations ◽  
Causal Direction ◽  
Carbon Isotope Excursion ◽  
Initial Carbon ◽  
Thermal Maximum ◽  
Carbon Injection ◽  
Permafrost Thawing

Abstract The Palaeocene–Eocene thermal maximum is a global warming period (~ 56 Ma), which is marked by a sharp negative carbon isotope excursion (CIE) that caused by the injection of massive isotopically-light carbon into the ocean-atmosphere. It is often considered that the carbon injection caused global warming. However, several studies have suggested that warming and environmental perturbations precede the onset of the CIE. Here we present Granger test to investigate the detailed mechanisms of this event. We show a shift from climate-warming driving carbon-emission scenario to a scheme in which carbon-injection causing global-warming during the CIE. The initial carbon emission might be from methane hydrates dissociation and/or permafrost thawing, possibly linked with astronomical paced warming. This change of causal direction may result from the warming feedback of the emitted carbon and additional carbon from other sources, such as volcanism, bolide impact, oxidation of marine organic matter, and wildfires burning peatlands.

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