Tethyan planktic foraminiferal record of the early Eocene hyperthermal events ETM2, H2 and I1 (Terche section, northeastern Italy)

2014 ◽  
Vol 31 ◽  
pp. 66-67 ◽  
Author(s):  
Roberta D'Onofrio
Keyword(s):  
Early Eocene ◽  
Northeastern Italy ◽  
Hyperthermal Events ◽  
Foraminiferal Record

scholarly journals Frequency, magnitude and character of hyperthermal events at the onset of the Early Eocene Climatic Optimum

2015 ◽  
Vol 11 (3) ◽  
pp. 1795-1820 ◽  
Author(s):  
V. Lauretano ◽  
K. Littler ◽  
M. Polling ◽  
J. C. Zachos ◽  
L. J. Lourens
Keyword(s):  
Water Mass ◽  
Intermediate Water ◽  
Early Eocene ◽  
Walvis Ridge ◽  
Early Eocene Climatic Optimum ◽  
Thermal Maximum ◽  
Carbon And Oxygen Isotope ◽  
Hyperthermal Events ◽  
Climatic Optimum ◽  
Δ13c And Δ18o

Abstract. Recent studies have shown that the Early Eocene Climatic Optimum (EECO) was preceded by a series of short-lived global warming events, known as hyperthermals. Here we present high-resolution benthic stable carbon and oxygen isotope records from ODP Sites 1262 and 1263 (Walvis Ridge, SE Atlantic) between ∼54 and ∼52 million years ago, tightly constraining the character, timing, and magnitude of six prominent hyperthermal events. These events, that include Eocene Thermal Maximum (ETM) 2 and 3, are studied in relation to orbital forcing and long-term trends. Our findings reveal an almost linear relationship between δ13C and δ18O for all these hyperthermals, indicating that the eccentricity-paced co-variance between extreme perturbations in the exogenic carbon pool and deep-sea temperatures persisted during the onset of the EECO, in accord with previous observations for the Paleocene Eocene Thermal Maximum (PETM) and ETM2. The covariance of δ13C and δ18O during H2 and I2, which are the second pulses of the "paired" hyperthermal events ETM2-H2 and I1-I2, deviates with respect to the other events. This could relate to a relatively higher contribution of an isotopically heavier source of carbon, such as peat or permafrost, and/or to climate feedbacks/local changes in circulation. Finally, the δ18O records of the two sites show a systematic offset with on average 0.2‰ heavier values for the shallower Site 1263, which we link to a slightly heavier (e.g. more saline) isotope composition of the intermediate water mass reaching the northeastern flank of the Walvis Ridge compared to that of the deeper northwestern water mass at Site 1262.

scholarly journals Geochemical indications for the Paleocene-Eocene Thermal Maximum (PETM) and Eocene Thermal Maximum 2 (ETM-2) hyperthermals in terrestrial sediments of the Canadian Arctic

Geosphere ◽  
2022 ◽  
Author(s):  
Lutz Reinhardt ◽  
Werner von Gosen ◽  
Andreas Lückge ◽  
Martin Blumenberg ◽  
Jennifer M. Galloway ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Early Eocene ◽  
Isotope Data ◽  
Complete Section ◽  
Thermal Maximum ◽  
Terrestrial Sediments ◽  
Deformation Features ◽  
Isotope Record ◽  
Hydrological System ◽  
Hyperthermal Events

During the late Paleocene to early Eocene, clastic fluvial sediments and coals were deposited in northern high latitudes as part of the Marga­ret Formation at Stenkul Fiord (Ellesmere Island, Nunavut, Canada). Syn-sedimentary tectonic movements of the Eurekan deformation continu­ously affected these terrestrial sediments. Different volcanic ash layers occur, and unconformities subdivide the deposits into four sedimentary units. Rare vertebrate fossils indicate an early Eocene (Graybullian) age for the upper part of the Stenkul Fiord outcrop. Here, we present carbon isotope data of bulk coal, related organic-rich mud and siltstones, a plant leaf wax-derived alkane, and additional plant remains. These data provide a complete carbon isotope record of one stratigraphic section with defined unconformity positions and in relation to other Eurekan deformation features. A previously dated ash layer MA-1 provided a U-Pb zircon age of 53.7 Ma and is used as a stratigraphic tie point, together with a discrete negative carbon isotope excursion found above MA-1 in a closely sampled coal seam. The excursion is identified as the likely expression of the I-1 hyperthermal event. Based on our isotope data that reflect the early Eocene dynamics of the carbon cycle, this tie point, and previous paleontological constraints from vertebrate fossils, the locations of the Paleocene-Eocene Thermal Maximum (PETM) and Eocene Thermal Maximum 2 (ETM-2) hyperthermals and their extent along the complete section are herein identified. Within the intervals of the PETM and ETM-2 hyperthermal events, increasing amounts of clastic sediments reached the site toward the respective end of the event. This is interpreted as a response of the fluvial depositional system to an intensified hydrological system during the hyperthermal events. Our study establishes an enhanced stratigraphic framework allowing for the calcula­tion of average sedimentation rates of different intervals and considerations on the completeness of the stratigraphic record. As one of the few high-latitude outcrops of early Eocene terrestrial sediments, the Stenkul Fiord location offers further possibilities to study the effects of extreme warming events in the Paleogene.

Clay mineralogical constraints on weathering in response to early Eocene hyperthermal events in the Bighorn Basin, Wyoming (Western Interior, USA)

2017 ◽  
Vol 129 (7-8) ◽  
pp. 997-1011 ◽  
Author(s):  
Chaowen Wang ◽  
Rieko Adriaens ◽  
Hanlie Hong ◽  
Jan Elsen ◽  
Noël Vandenberghe ◽  
...  
Keyword(s):  
Bighorn Basin ◽  
Early Eocene ◽  
Hyperthermal Events

PLANKTONIC FORAMINIFERAL BLEACHING DURING EARLY EOCENE HYPERTHERMAL EVENTS

2017 ◽  
Author(s):  
Jack Oliver Shaw ◽  
◽  
Simon D'haenens ◽  
Ellen Thomas ◽  
Pincelli M. Hull
Keyword(s):  
Early Eocene ◽  
Hyperthermal Events

scholarly journals Major perturbations in the global carbon cycle and photosymbiont-bearing planktic foraminifera during the early Eocene

2016 ◽  
Vol 12 (4) ◽  
pp. 981-1007 ◽  
Author(s):  
Valeria Luciani ◽  
Gerald R. Dickens ◽  
Jan Backman ◽  
Eliana Fornaciari ◽  
Luca Giusberti ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Northwest Pacific ◽  
Early Eocene ◽  
Ocean Drilling Program ◽  
Low Latitude ◽  
Planktic Foraminifera ◽  
Early Eocene Climatic Optimum ◽  
Carbon And Oxygen Isotope ◽  
Hyperthermal Events ◽  
Global Carbon

Abstract. A marked switch in the abundance of the planktic foraminiferal genera Morozovella and Acarinina occurred at low-latitude sites near the start of the Early Eocene Climatic Optimum (EECO), a multi-million-year interval when Earth surface temperatures reached their Cenozoic maximum. Stable carbon and oxygen isotope data of bulk sediment are presented from across the EECO at two locations: Possagno in northeast Italy and Deep Sea Drilling Project (DSDP) Site 577 in the northwest Pacific. Relative abundances of planktic foraminifera are presented from these two locations, as well as from Ocean Drilling Program (ODP) Site 1051 in the northwest Atlantic. All three sections have good stratigraphic markers, and the δ13C records at each section can be correlated amongst each other and to δ13C records at other locations across the globe. These records show that a series of negative carbon isotope excursions (CIEs) occurred before, during and across the EECO, which is defined here as the interval between the J event and the base of Discoaster sublodoensis. Significant though ephemeral modifications in planktic foraminiferal assemblages coincide with some of the short-term CIEs, which were marked by increases in the relative abundance of Acarinina, similar to what happened across established hyperthermal events in Tethyan settings prior to the EECO. Most crucially, a temporal link exists between the onset of the EECO, carbon cycle changes during this time and the decline in Morozovella. Possible causes are manifold and may include temperature effects on photosymbiont-bearing planktic foraminifera and changes in ocean chemistry.

scholarly journals Astronomical calibration of the Ypresian timescale: implications for seafloor spreading rates and the chaotic behavior of the solar system?

2017 ◽  
Vol 13 (9) ◽  
pp. 1129-1152 ◽  
Author(s):  
Thomas Westerhold ◽  
Ursula Röhl ◽  
Thomas Frederichs ◽  
Claudia Agnini ◽  
Isabella Raffi ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Solar System ◽  
Chaotic Behavior ◽  
Major Change ◽  
Early Eocene ◽  
Chaotic Diffusion ◽  
Planetary Orbits ◽  
Hyperthermal Events ◽  
Age Model ◽  
Spreading Rates

Abstract. To fully understand the global climate dynamics of the warm early Eocene with its reoccurring hyperthermal events, an accurate high-fidelity age model is required. The Ypresian stage (56–47.8 Ma) covers a key interval within the Eocene as it ranges from the warmest marine temperatures in the early Eocene to the long-term cooling trends in the middle Eocene. Despite the recent development of detailed marine isotope records spanning portions of the Ypresian stage, key records to establish a complete astronomically calibrated age model for the Ypresian are still missing. Here we present new high-resolution X-ray fluorescence (XRF) core scanning iron intensity, bulk stable isotope, calcareous nannofossil, and magnetostratigraphic data generated on core material from ODP Sites 1258 (Leg 207, Demerara Rise), 1262, 1263, 1265, and 1267 (Leg 208, Walvis Ridge) recovered in the equatorial and South Atlantic Ocean. By combining new data with published records, a 405 kyr eccentricity cyclostratigraphic framework was established, revealing a 300–400 kyr long condensed interval for magnetochron C22n in the Leg 208 succession. Because the amplitudes are dominated by eccentricity, the XRF data help to identify the most suitable orbital solution for astronomical tuning of the Ypresian. Our new records fit best with the La2010b numerical solution for eccentricity, which was used as a target curve for compiling the Ypresian astronomical timescale (YATS). The consistent positions of the very long eccentricity minima in the geological data and the La2010b solution suggest that the macroscopic feature displaying the chaotic diffusion of the planetary orbits, the transition from libration to circulation in the combination of angles in the precession motion of the orbits of Earth and Mars, occurred  ∼  52 Ma. This adds to the geological evidence for the chaotic behavior of the solar system. Additionally, the new astrochronology and revised magnetostratigraphy provide robust ages and durations for Chrons C21n to C24n (47–54 Ma), revealing a major change in spreading rates in the interval from 51.0 to 52.5 Ma. This major change in spreading rates is synchronous with a global reorganization of the plate–mantle system and the chaotic diffusion of the planetary orbits. The newly provided YATS also includes new absolute ages for biostratigraphic events, magnetic polarity reversals, and early Eocene hyperthermal events. Our new bio- and magnetostratigraphically calibrated stable isotope compilation may act as a reference for further paleoclimate studies of the Ypresian, which is of special interest because of the outgoing warming and increasingly cooling phase. Finally, our approach of integrating the complex comprehensive data sets unearths some challenges and uncertainties but also validates the high potential of chemostratigraphy, magnetostratigraphy, and biostratigraphy in unprecedented detail being most significant for an accurate chronostratigraphy.

HIGH ARCTIC FOREST DIVERSITY AND FLORISTIC CHANGE DURING EARLY EOCENE HYPERTHERMAL EVENTS

2019 ◽  
Author(s):  
Christopher K. West ◽  
◽  
David R. Greenwood ◽  
Markus Sudermann ◽  
Lutz Reinhardt ◽  
...  
Keyword(s):  
High Arctic ◽  
Early Eocene ◽  
Forest Diversity ◽  
Hyperthermal Events ◽  
Floristic Change
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