Early Eocene Climatic Optimum

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The Early Eocene Climatic Optimum (EECO), also referred to as the Early Eocene Thermal Maximum (EETM), [1] was a period of extremely warm greenhouse climatic conditions during the Eocene epoch. The EECO represented the hottest sustained interval of the Cenozoic era and one of the hottest periods in all of Earth's history. [2]

Contents

Duration

The EECO lasted from about 54 to 49 Ma. [1] The EECO's onset is signified by a major geochemical enrichment in isotopically light carbon, commonly known as a negative δ13C excursion, that demarcates the hyperthermal Eocene Thermal Maximum 3 (ETM3). [3]

Climate

Following some climate models, the EECO was marked by an extremely high global mean surface temperature, [1] which has been estimated to be anywhere between 23.2 and 29.7 °C, with the mean estimate being around 27.0 °C. [4] In North America, the mean annual temperature was 23.0 °C, while the continent's overall mean annual precipitation (MAP) was about 1500 mm. [2] The mean annual temperature range (MATR) of North America may have been as low as 47 °C or as high as 61 °C, while the MATR of Asia was anywhere from 51 to 60 °C. [5] The Okanagan Highlands had a moist mesothermal climate, with bioclimatic analysis of the region yielding estimates of a mean annual temperature (MAT) of 12.7-16.6 °C, a cold month mean temperature (CMMT) of 3.5-7.9 °C, and a MAP of 103-157 cm. [6] Clumped isotope measurements from the Green River Basin confirm a high seasonality of temperature, contradicting climatological predictions of an equable climate under greenhouse conditions. [7] Sediments from San Diego County, California record a MAP of 1100 ± 299 mm, notably drier than the region was during the Palaeocene-Eocene Thermal Maximum. [8] Sea surface temperatures (SSTs) off of Seymour Island were ~15 °C. [9] The high elevation areas of Asia, Africa, and Antarctica saw elevation dependent warming (EDW), while those in North America and India saw elevation dependent cooling (EDC). [10]

The latitudinal climate gradient is generally believed to have been smaller, which was mainly the result of a decrease in albedo differences across Earth's surface. [11] Although SSTs are often believed to have had a shallow latitudinal temperature gradient, this is likely to be an artefact of burial-induced oxygen isotope reequilibration in fossilised benthic foraminifera. [12]

Climate modelling simulations point to a carbon dioxide concentration in the atmosphere of about 1,680 ppm to reproduce the observed hothouse conditions of the EECO, [13] although geochemical proxies suggest only 700-900 ppm. [14] Stomatal density in Gingko leaves suggests pCO2 was over twice that of preindustrial levels. [15] Additionally, methane concentrations in the Early Eocene may have been significantly higher than in the present day. [16]

The nature of the hydrological cycle during the EECO is controversial. Evidence from German peat bogs suggests that it was highly variable, with alternations between aridity and humidity. [17] Evidence from North America, in contrast, suggests that the hydrological cycle was enhanced during the EECO, although it remained relatively stable, unlike during the earlier hyperthermals, and that the stable hydroclimate may ultimately have ended the EECO by enabling high rates of organic carbon burial in lacustrine settings. [18]

Causes

The EECO was preceded by a major long-term warming trend in the Late Palaeocene and Early Eocene. [19] It was initiated by a series of intense hyperthermal events in the Early Eocene, including Eocene Thermal Maximum 2 (ETM2) and ETM3. [20]

The emplacement of the Pana Formation, a volcanic rock formation in southern Tibet that may represent the product of a supereruption, has also been proposed as a source of excess carbon flux into the atmosphere that drove the EECO. [21] Other research attributes the elevated greenhouse gas levels to increased generation of petroleum in sedimentary basins and enhanced ventilation of marine carbon. [22]

Biotic effects

The final phase of the Angiosperm Terrestrial Revolution occurred during the EECO. [23] The supergreenhouse climate of the EECO fostered extensive floral diversification and increased habitat complexity in North American terrestrial biomes. [2] The hot, humid conditions of the EECO may have facilitated the evolution of epiphytic bryophytes, with the oldest member of Lejeuneaceae being described from fossils from the Cambay amber dating back to the EECO. [24] The Okanagan Highlands in British Columbia became a biodiversity hotspot from which newly evolved lineages of temperate-adapted plants radiated from following the end of the EECO. [25]

The climate was warm enough to allow palms and palm beetles to inhabit upland regions of British Columbia and Washington. [26] Ellesmere Island became inhabited by basal primatomorphs. [27]

Northern Yakutia was covered in mangroves. [28] Mongolia witnessed a humidification event that transformed it from a shrubland into a forest and significantly reducing local wildfire incidence. [29]

In South America, the EECO coincided with the Itaboraian South American Land Mammal Age. [30] Cingulates diversified over the course of the EECO. [31]

The northern margins of the Australo-Antarctic Gulf, then located at 60-65 °S, were covered in wet-tropical lowland vegetation. [32]

The euryhaline dinoflagellate Homotryblium became superabundant at the site of Waipara in New Zealand during the early and middle EECO, reflecting the occurrence of significant stratification of surficial waters as well as increased salinity. [33]

Geologic effects

The EECO caused an increase in chert deposition by way of basin–basin fractionation by deep-sea circulation, causing increased silica concentrations in the North Atlantic which in turn resulted in direct precipitation of silica as well as its absorption by clay minerals. [34]

Comparison to present global warming

Because the pCO2 values of the EECO could potentially be reached if anthropogenic greenhouse gas emissions continue unabated for three centuries, the EECO has been used as an analogue for high-end projections of the Earth's future climate that would result from humanity's burning of fossil fuels. [35] Based on the Representative Concentration Pathway 8.5 (RCP8.5) emission scenario, by 2150 CE, the climates across much of the world would resemble conditions during the EECO. [36]

See also

Related Research Articles

<span class="mw-page-title-main">Eocene</span> Second epoch of the Paleogene Period

The Eocene is a geological epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name Eocene comes from the Ancient Greek Ἠώς and καινός and refers to the "dawn" of modern ('new') fauna that appeared during the epoch.

The Holocene is the current geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene together form the Quaternary period. The Holocene is an interglacial period within the ongoing glacial cycles of the Quaternary, and is equivalent to Marine Isotope Stage 1.

The Miocene is the first geological epoch of the Neogene Period and extends from about 23.03 to 5.333 million years ago (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words μείων and καινός and means "less recent" because it has 18% fewer modern marine invertebrates than the Pliocene has. The Miocene is preceded by the Oligocene and is followed by the Pliocene.

<span class="mw-page-title-main">Neogene</span> Second geologic period in the Cenozoic Era 23–2.6 million years ago

The Neogene is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period 23.03 million years ago (Mya) to the beginning of the present Quaternary Period 2.58 million years ago. The Neogene is sub-divided into two epochs, the earlier Miocene and the later Pliocene. Some geologists assert that the Neogene cannot be clearly delineated from the modern geological period, the Quaternary. The term "Neogene" was coined in 1853 by the Austrian palaeontologist Moritz Hörnes (1815–1868). The earlier term Tertiary Period was used to define the span of time now covered by Paleogene and Neogene and, despite no longer being recognized as a formal stratigraphic term, "Tertiary" still sometimes remains in informal use.

The Oligocene is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present. As with other older geologic periods, the rock beds that define the epoch are well identified but the exact dates of the start and end of the epoch are slightly uncertain. The name Oligocene was coined in 1854 by the German paleontologist Heinrich Ernst Beyrich from his studies of marine beds in Belgium and Germany. The name comes from Ancient Greek ὀλίγος (olígos) 'few' and καινός (kainós) 'new', and refers to the sparsity of extant forms of molluscs. The Oligocene is preceded by the Eocene Epoch and is followed by the Miocene Epoch. The Oligocene is the third and final epoch of the Paleogene Period.

<span class="mw-page-title-main">Paleogene</span> First period of the Cenozoic Era (66–23 million years ago)

The Paleogene Period is a geologic period and system that spans 43 million years from the end of the Cretaceous Period 66 Ma to the beginning of the Neogene Period 23.03 Ma. It is the first period of the Cenozoic Era and is divided into the Paleocene, Eocene, and Oligocene epochs. The earlier term Tertiary Period was used to define the time now covered by the Paleogene Period and subsequent Neogene Period; despite no longer being recognized as a formal stratigraphic term, "Tertiary" still sometimes remains in informal use. Paleogene is often abbreviated "Pg", although the United States Geological Survey uses the abbreviation "Pe" for the Paleogene on the Survey's geologic maps.

<span class="mw-page-title-main">Paleocene–Eocene Thermal Maximum</span> Global warming about 55 million years ago

The Paleocene–Eocene thermal maximum (PETM), alternatively ”Eocene thermal maximum 1 (ETM1)“ and formerly known as the "Initial Eocene" or “Late Paleocene thermal maximum", was a geologically brief time interval characterized by a 5–8 °C global average temperature rise and massive input of carbon into the ocean and atmosphere. The event began, now formally, at the time boundary between the Paleocene and Eocene geological epochs. The exact age and duration of the PETM remain uncertain, but it occurred around 55.8 million years ago (Ma) and lasted about 200 thousand years (Ka).

The Holocene Climate Optimum (HCO) was a warm period in the first half of the Holocene epoch, that occurred in the interval roughly 9,500 to 5,500 years BP, with a thermal maximum around 8000 years BP. It has also been known by many other names, such as Altithermal, Climatic Optimum, Holocene Megathermal, Holocene Optimum, Holocene Thermal Maximum, Hypsithermal, and Mid-Holocene Warm Period.

<span class="mw-page-title-main">Abrupt climate change</span> Form of climate change

An abrupt climate change occurs when the climate system is forced to transition at a rate that is determined by the climate system energy-balance. The transition rate is more rapid than the rate of change of the external forcing, though it may include sudden forcing events such as meteorite impacts. Abrupt climate change therefore is a variation beyond the variability of a climate. Past events include the end of the Carboniferous Rainforest Collapse, Younger Dryas, Dansgaard–Oeschger events, Heinrich events and possibly also the Paleocene–Eocene Thermal Maximum. The term is also used within the context of climate change to describe sudden climate change that is detectable over the time-scale of a human lifetime. Such a sudden climate change can be the result of feedback loops within the climate system or tipping points in the climate system.

<span class="mw-page-title-main">Ypresian</span> First age of the Eocene Epoch

In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between 56 and47.8 Ma, is preceded by the Thanetian Age and is followed by the Eocene Lutetian Age. The Ypresian is consistent with the Lower Eocene.

<span class="mw-page-title-main">Clathrate gun hypothesis</span> Meteorological hypothesis

The clathrate gun hypothesis is a proposed explanation for the periods of rapid warming during the Quaternary. The hypothesis is that changes in fluxes in upper intermediate waters in the ocean caused temperature fluctuations that alternately accumulated and occasionally released methane clathrate on upper continental slopes. This would have had an immediate impact on the global temperature, as methane is a much more powerful greenhouse gas than carbon dioxide. Despite its atmospheric lifetime of around 12 years, methane's global warming potential is 72 times greater than that of carbon dioxide over 20 years, and 25 times over 100 years. It is further proposed that these warming events caused the Bond Cycles and individual interstadial events, such as the Dansgaard–Oeschger interstadials.

<span class="mw-page-title-main">Eocene–Oligocene extinction event</span> Mass extinction event 33.9 million years ago

The Eocene–Oligocene extinction event, also called the Eocene-Oligocene transition (EOT) or Grande Coupure, is the transition between the end of the Eocene and the beginning of the Oligocene, an extinction event and faunal turnover occurring between 33.9 and 33.4 million years ago. It was marked by large-scale extinction and floral and faunal turnover, although it was relatively minor in comparison to the largest mass extinctions.

The Middle Miocene Climatic Transition (MMCT) was a relatively steady period of climatic cooling that occurred around the middle of the Miocene, roughly 14 million years ago (Ma), during the Langhian stage, and resulted in the growth of ice sheet volumes globally, and the reestablishment of the ice of the East Antarctic Ice Sheet (EAIS). The term Middle Miocene disruption, alternatively the Middle Miocene extinction or Middle Miocene extinction peak, refers to a wave of extinctions of terrestrial and aquatic life forms that occurred during this climatic interval. This period was preceded by the Middle Miocene Climatic Optimum (MMCO), a period of relative warmth from 18 to 14 Ma. Cooling that led to the Middle Miocene disruption is primarily attributed CO2 being pulled out of the Earth's atmosphere by organic material before becoming caught in different locations like the Monterey Formation. These may have been amplified by changes in oceanic and atmospheric circulation due to continental drift. Additionally, orbitally paced factors may also have played a role.

Eocene Thermal Maximum 2 (ETM-2), also called H-1 or Elmo, was a transient period of global warming that occurred around 54 Ma. It was the second major hyperthermal that punctuated long-term warming from the Late Paleocene through the Early Eocene.

<i>Tilia johnsoni</i> Extinct species of flowering plant

Tilia johnsoni is an extinct species of flowering plant in the family Malvaceae that, as a member of the genus Tilia, is related to modern lindens. The species is known from fossil leaves found in the early Eocene deposits of northern Washington state, United States and a similar aged formation in British Columbia, Canada.

<span class="mw-page-title-main">Middle Pliocene Warm Period</span>

The Middle Pliocene Warm Period (mPWP), also known as the Mid-Piacenzian Warm Period or the Pliocene Thermal Maximum, was an interval of warm climate during the Pliocene epoch that lasted from 3.3 to 3.0 million years ago (Ma).

The Middle Eocene Climatic Optimum (MECO), also called the Middle Eocene Thermal Maximum (METM), was a period of very warm climate that occurred during the Bartonian, from around 40.5 to 40.0 Ma. It marked a notable reversal of the overall trend of global cooling that characterised the Middle and Late Eocene.

The Coldwater Beds are a geologic formation of the Okanagan Highlands in British Columbia, Canada. They preserve fossils dating back to the Ypresian stage of the Eocene period, or Wasatchian in the NALMA classification.

A hyperthermal event corresponds to a sudden warming of the planet on a geologic time scale.

The Middle Miocene Climatic Optimum (MMCO), sometimes referred to as the Middle Miocene Thermal Maximum (MMTM), was an interval of warm climate during the Miocene epoch, specifically the Burdigalian and Langhian stages.

References

  1. 1 2 3 Scotese, Christopher R.; Song, Haijun; Mills, Benjamin J.W.; van der Meer, Douwe G. (1 April 2021). "Phanerozoic paleotemperatures: The earth's changing climate during the last 540 million years". Earth-Science Reviews . 215: 103503. Bibcode:2021ESRv..21503503S. doi:10.1016/j.earscirev.2021.103503. S2CID   233579194 . Retrieved 24 December 2023– via Elsevier Science Direct.
  2. 1 2 3 Woodburne, Michael O.; Gunnell, Gregg F.; Stucky, Richard K. (11 August 2009). "Climate directly influences Eocene mammal faunal dynamics in North America". Proceedings of the National Academy of Sciences of the United States of America . 106 (32): 13399–13403. Bibcode:2009PNAS..10613399W. doi: 10.1073/pnas.0906802106 . ISSN   0027-8424. PMC   2726358 . PMID   19666605.
  3. ↑ Slotnick, B. S.; Dickens, G. R.; Hollis, C. J.; Crampton, J. S.; Strong, C. Percy; Phillips, A. (17 September 2015). "The onset of the Early Eocene Climatic Optimum at Branch Stream, Clarence River valley, New Zealand". New Zealand Journal of Geology and Geophysics . 58 (3): 262–280. Bibcode:2015NZJGG..58..262S. doi: 10.1080/00288306.2015.1063514 . S2CID   130982094.
  4. ↑ Inglis, Gordon N.; Bragg, Fran; Burls, Natalie J.; Cramwinckel, Margot J.; Evans, David; Foster, Gavin L.; Huber, Matthew; Lunt, Daniel J.; Siler, Nicholas; Steinig, Sebastian; Tierney, Jessica E.; Wilkinson, Richard; Anagnostou, Eleni; de Boer, Agatha M.; Dunkley Jones, Tom; Edgar, Kirsty M.; Hollis, Christopher J.; Hutchinson, David K.; Pancost, Richard D. (26 October 2020). "Global mean surface temperature and climate sensitivity of the early Eocene Climatic Optimum (EECO), Paleocene–Eocene Thermal Maximum (PETM), and latest Paleocene". Climate of the Past . 16 (5): 1953–1968. Bibcode:2020CliPa..16.1953I. doi: 10.5194/cp-16-1953-2020 . hdl: 1983/24a30f12-51a6-4544-9db8-b2009e33c02a . ISSN   1814-9332 . Retrieved 24 December 2023.
  5. ↑ Sloan, L.Cirbus; Morrill, C (15 November 1998). "Orbital forcing and Eocene continental temperatures". Palaeogeography, Palaeoclimatology, Palaeoecology . 144 (1–2): 21–35. Bibcode:1998PPP...144...21S. doi:10.1016/S0031-0182(98)00091-1 . Retrieved 24 December 2023– via Elsevier Science Direct.
  6. ↑ Mathewes, Rolf W.; Greenwood, David R.; Archibald, S. Bruce (14 April 2016). Pigg, Kathleen B. (ed.). "Paleoenvironment of the Quilchena flora, British Columbia, during the Early Eocene Climatic Optimum". Canadian Journal of Earth Sciences . 53 (6): 574–590. Bibcode:2016CaJES..53..574M. doi:10.1139/cjes-2015-0163. hdl: 1807/71979 . ISSN   0008-4077 . Retrieved 5 July 2024– via Canadian Science Publishing.
  7. ↑ Hyland, Ethan G.; Huntington, Katharine W.; Sheldon, Nathan D.; Reichgelt, Tammo (4 October 2018). "Temperature seasonality in the North American continental interior during the Early Eocene Climatic Optimum". Climate of the Past . 14 (10): 1391–1404. Bibcode:2018CliPa..14.1391H. doi: 10.5194/cp-14-1391-2018 . hdl: 2027.42/148644 . ISSN   1814-9332 . Retrieved 3 February 2024.
  8. ↑ Broz, Adrian P.; Pritchard-Peterson, Devin; Spinola, Diogo; Schneider, Sarah; Retallack, Gregory; Silva, Lucas C. R. (31 January 2024). "Eocene (50–55 Ma) greenhouse climate recorded in nonmarine rocks of San Diego, CA, USA". Scientific Reports . 14 (1): 2613. Bibcode:2024NatSR..14.2613B. doi:10.1038/s41598-024-53210-0. ISSN   2045-2322. PMC   10830502 . PMID   38297060.
  9. ↑ Ivany, L. C.; Lohmann, K. C.; Hasiuk, F.; Blake, D. B.; Glass, A.; Aronson, R. B.; Moody, R. M. (1 May 2008). "Eocene climate record of a high southern latitude continental shelf: Seymour Island, Antarctica". Geological Society of America Bulletin . 120 (5–6): 659–678. Bibcode:2008GSAB..120..659I. doi:10.1130/B26269.1. ISSN   0016-7606 – via GeoScienceWorld.
  10. ↑ Kad, Pratik; Blau, Manuel Tobias; Ha, Kyung-Ja; Zhu, Jiang (1 November 2022). "Elevation-dependent temperature response in early Eocene using paleoclimate model experiment". Environmental Research Letters . 17 (11): 114038. Bibcode:2022ERL....17k4038K. doi: 10.1088/1748-9326/ac9c74 . ISSN   1748-9326.
  11. ↑ Lunt, Daniel J.; Bragg, Fran; Chan, Wing-Le; Hutchinson, David K.; Ladant, Jean-Baptiste; Morozova, Polina; Niezgodzki, Igor; Steinig, Sebastian; Zhang, Zhongshi; Zhu, Jiang; Abe-Ouchi, Ayako; Anagnostou, Eleni; de Boer, Agatha M.; Coxall, Helen K.; Donnadieu, Yannick; Foster, Gavin; Inglis, Gordon N.; Knorr, Gregor; Langebroek, Petra M.; Lear, Caroline H.; Lohmann, Gerrit; Poulsen, Christopher J.; Sepulchre, Pierre; Tierney, Jessica E.; Valdes, Paul J.; Volodin, Evgeny M.; Jones, Tom Dunkley; Hollis, Christopher J.; Huber, Matthew; Otto-Bliesner, Bette L. (15 January 2021). "DeepMIP: model intercomparison of early Eocene climatic optimum (EECO) large-scale climate features and comparison with proxy data". Climate of the Past . 17 (1): 203–227. Bibcode:2021CliPa..17..203L. doi: 10.5194/cp-17-203-2021 . hdl: 1983/22ea9a7d-eccc-4eca-b04d-7f003e8d1d2e . ISSN   1814-9332 . Retrieved 25 June 2024.
  12. ↑ Bernard, S.; Daval, D.; Ackerer, P.; Pont, S.; Meibom, A. (26 October 2017). "Burial-induced oxygen-isotope re-equilibration of fossil foraminifera explains ocean paleotemperature paradoxes". Nature Communications . 8 (1): 1134. Bibcode:2017NatCo...8.1134B. doi: 10.1038/s41467-017-01225-9 . ISSN   2041-1723. PMC   5656689 . PMID   29070888.
  13. ↑ Goudsmit-Harzevoort, Barbara; Lansu, Angelique; Baatsen, Michiel L. J.; von der Heydt, Anna S.; de Winter, Niels J.; Zhang, Yurui; Abe-Ouchi, Ayako; de Boer, Agatha; Chan, Wing-Le; Donnadieu, Yannick; Hutchinson, David K.; Knorr, Gregor; Ladant, Jean-Baptiste; Morozova, Polina; Niezgodzki, Igor; Steinig, Sebastian; Tripati, Aradhna; Zhang, Zhongshi; Zhu, Jiang; Ziegler, Martin (17 February 2023). "The Relationship Between the Global Mean Deep-Sea and Surface Temperature During the Early Eocene". Paleoceanography and Paleoclimatology . 38 (3): 1–18. Bibcode:2023PaPa...38.4532G. doi: 10.1029/2022PA004532 . ISSN   2572-4517.
  14. ↑ Pearson, Paul N.; Palmer, Martin R. (17 August 2000). "Atmospheric carbon dioxide concentrations over the past 60 million years". Nature . 406 (6797): 695–699. Bibcode:2000Natur.406..695P. doi:10.1038/35021000. ISSN   1476-4687. PMID   10963587. S2CID   205008176 . Retrieved 24 December 2023.
  15. ↑ Smith, Robin Y.; Greenwood, David R.; Basinger, James F. (1 July 2010). "Estimating paleoatmospheric pCO2 during the Early Eocene Climatic Optimum from stomatal frequency of Ginkgo, Okanagan Highlands, British Columbia, Canada". Palaeogeography, Palaeoclimatology, Palaeoecology . 293 (1–2): 120–131. Bibcode:2010PPP...293..120S. doi:10.1016/j.palaeo.2010.05.006 . Retrieved 25 June 2024– via Elsevier Science Direct.
  16. ↑ Sloan, L. Cirbus; Walker, James C. G.; Moore, T. C.; Rea, David K.; Zachos, James C. (28 May 1992). "Possible methane-induced polar warming in the early Eocene". Nature . 357 (6376): 320–322. Bibcode:1992Natur.357..320S. doi:10.1038/357320a0. hdl: 2027.42/62963 . ISSN   0028-0836. PMID   11536496. S2CID   4348331 . Retrieved 24 December 2023.
  17. ↑ Riegel, Walter; Wilde, Volker (1 April 2016). "An early Eocene Sphagnum bog at Schöningen, northern Germany". International Journal of Coal Geology. 159: 57–70. Bibcode:2016IJCG..159...57R. doi:10.1016/j.coal.2016.03.021 . Retrieved 25 June 2024– via Elsevier Science Direct.
  18. ↑ Elson, Amy L.; Rohrssen, Megan; Marshall, John; Inglis, Gordon N.; Whiteside, Jessica H. (1 June 2022). "Hydroclimate variability in the United States continental interior during the early Eocene Climatic Optimum". Palaeogeography, Palaeoclimatology, Palaeoecology . 595: 110959. Bibcode:2022PPP...59510959E. doi:10.1016/j.palaeo.2022.110959 . Retrieved 25 June 2024– via Elsevier Science Direct.
  19. ↑ Zachos, James; Pagani, Mark; Sloan, Lisa; Thomas, Ellen; Billups, Katharina (27 April 2001). "Trends, Rhythms, and Aberrations in Global Climate 65 Ma to Present". Science . 292 (5517): 686–693. Bibcode:2001Sci...292..686Z. doi:10.1126/science.1059412. ISSN   0036-8075. PMID   11326091. S2CID   2365991 . Retrieved 24 December 2023.
  20. ↑ Lauretano, V.; Littler, K.; Polling, M.; Zachos, J. C.; Lourens, L. J. (7 October 2015). "Frequency, magnitude and character of hyperthermal events at the onset of the Early Eocene Climatic Optimum". Climate of the Past . 11 (10): 1313–1324. Bibcode:2015CliPa..11.1313L. doi: 10.5194/cp-11-1313-2015 . ISSN   1814-9332 . Retrieved 24 December 2023.
  21. ↑ Zhang, Shao-Hua; Ji, Wei-Qiang; Chen, Hou-Bin; Kirstein, Linda A.; Wu, Fu-Yuan (June 2023). "Linking rapid eruption of the Linzizong volcanic rocks and Early Eocene Climatic Optimum (EECO): Constraints from the Pana Formation in the Linzhou and Pangduo basins, southern Tibet". Lithos . 446–447: 107159. Bibcode:2023Litho.44607159Z. doi:10.1016/j.lithos.2023.107159. hdl: 20.500.11820/5605da8a-33fd-42ee-8d54-68590a4e12f8 . S2CID   257848801 . Retrieved 24 December 2023– via Elsevier Science Direct.
  22. ↑ Hyland, E.; Sheldon, N. D.; Fan, M. (1 July 2013). "Terrestrial paleoenvironmental reconstructions indicate transient peak warming during the early Eocene climatic optimum". Geological Society of America Bulletin . 125 (7–8): 1338–1348. Bibcode:2013GSAB..125.1338H. doi:10.1130/B30761.1. ISSN   0016-7606 . Retrieved 5 July 2024– via GeoScienceWorld.
  23. ↑ Benton, Michael James; Wilf, Peter; Sauquet, Hervé (26 October 2021). "The Angiosperm Terrestrial Revolution and the origins of modern biodiversity". New Phytologist . 233 (5): 2017–2035. doi:10.1111/nph.17822. hdl: 1983/82a09075-31f4-423e-98b9-3bb2c215e04b . PMID   34699613. S2CID   240000207 . Retrieved 24 November 2022.
  24. ↑ Heinrichs, Jochen; Scheben, Armin; Bechteler, Julia; Lee, Gaik Ee; Schäfer-Verwimp, Alfons; Hedenäs, Lars; Singh, Hukam; Pócs, Tamás; Nascimbene, Paul C.; Peralta, Denilson F.; Renner, Matt; Schmidt, Alexander R. (31 May 2016). Wong, William Oki (ed.). "Crown Group Lejeuneaceae and Pleurocarpous Mosses in Early Eocene (Ypresian) Indian Amber". PLOS ONE . 11 (5): e0156301. Bibcode:2016PLoSO..1156301H. doi: 10.1371/journal.pone.0156301 . ISSN   1932-6203. PMC   4887038 . PMID   27244582.
  25. ↑ Smith, Robin Y.; Basinger, James F.; Greenwood, David R. (21 October 2011). "Early Eocene plant diversity and dynamics in the Falkland flora, Okanagan Highlands, British Columbia, Canada". Palaeobiodiversity and Palaeoenvironments. 92 (3): 309–328. doi:10.1007/s12549-011-0061-5. ISSN   1867-1594 . Retrieved 25 June 2024– via Springer Link.
  26. ↑ Archibald, S. Bruce; Morse, Geoffrey E.; Greenwood, David R.; Mathewes, Rolf W. (12 May 2014). "Fossil palm beetles refine upland winter temperatures in the Early Eocene Climatic Optimum". Proceedings of the National Academy of Sciences of the United States of America . 111 (22): 8095–8100. Bibcode:2014PNAS..111.8095A. doi: 10.1073/pnas.1323269111 . ISSN   0027-8424. PMC   4050627 . PMID   24821798.
  27. ↑ Miller, Kristen; Tietjen, Kristen; Beard, K. Christopher (25 January 2023). Meloro, Carlo (ed.). "Basal Primatomorpha colonized Ellesmere Island (Arctic Canada) during the hyperthermal conditions of the early Eocene climatic optimum". PLOS ONE . 18 (1): e0280114. Bibcode:2023PLoSO..1880114M. doi: 10.1371/journal.pone.0280114 . ISSN   1932-6203. PMC   9876366 . PMID   36696373.
  28. ↑ Bondarenko, Olesya V.; Utescher, Torsten (19 May 2022). "Late early to early middle Eocene climate and vegetation change at Tastakh Lake (northern Yakutia, eastern Siberia)". Palaeobiodiversity and Palaeoenvironments. 103 (2): 277–301. doi: 10.1007/s12549-022-00530-6 . ISSN   1867-1594 . Retrieved 5 July 2024– via Springer Link.
  29. ↑ Zhou, Xinying; Wang, Jian; Li, Qian; Bai, Bin; Mao, Fangyuan; Li, Xiaoqiang; Wang, Yuan-Qing (29 June 2023). "Late Paleocene to early Oligocene fire ecology of the south Mongolian highland". Frontiers in Earth Science . 11. Bibcode:2023FrEaS..1171452Z. doi: 10.3389/feart.2023.1171452 . ISSN   2296-6463.
  30. ↑ Woodburne, Michael O.; Goin, Francisco J.; Raigemborn, Maria Sol; Heizler, Matt; Gelfo, Javier N.; Oliveira, Edison V. (October 2014). "Revised timing of the South American early Paleogene land mammal ages". Journal of South American Earth Sciences . 54: 109–119. Bibcode:2014JSAES..54..109W. doi:10.1016/j.jsames.2014.05.003. hdl: 11336/79162 . Retrieved 3 February 2024– via Elsevier Science Direct.
  31. ↑ Fernicola, Juan Carlos; Zimicz, Ana N.; Chornogubsky, Laura; Ducea, Mihai; Cruz, Laura E.; Bond, Mariano; Arnal, Michelle; Cárdenas, Magalí; Fernández, Mercedes (10 May 2021). "The Early Eocene Climatic Optimum at the Lower Section of the Lumbrera Formation (Ypresian, Salta Province, Northwestern Argentina): Origin and Early Diversification of the Cingulata". Journal of Mammalian Evolution . 28 (3): 621–633. doi:10.1007/s10914-021-09545-w. ISSN   1064-7554. S2CID   236602601 . Retrieved 3 February 2024– via Springer.
  32. ↑ McGowran, Brian; Hill, Robert S. (9 June 2015). "Cenozoic climatic shifts in southern Australia". Transactions of the Royal Society of South Australia . 139 (1): 19–37. Bibcode:2015TRSAu.139...19M. doi:10.1080/03721426.2015.1035215. ISSN   0372-1426 . Retrieved 5 July 2024– via Taylor and Francis Online.
  33. ↑ Crouch, E. M.; Shepherd, C. L.; Morgans, H. E. G.; Naafs, B. D. A.; Dallanave, E.; Phillips, A.; Hollis, C. J.; Pancost, R. D. (1 January 2020). "Climatic and environmental changes across the early Eocene climatic optimum at mid-Waipara River, Canterbury Basin, New Zealand". Earth-Science Reviews . 200: 102961. Bibcode:2020ESRv..20002961C. doi:10.1016/j.earscirev.2019.102961. hdl: 1983/aedc04cc-bba8-44c6-8f9d-ba398bb24607 . ISSN   0012-8252. S2CID   210618370 . Retrieved 11 September 2023.
  34. ↑ Muttoni, Giovanni; Kent, Dennis V. (27 September 2007). "Widespread formation of cherts during the early Eocene climate optimum". Palaeogeography, Palaeoclimatology, Palaeoecology . 253 (3–4): 348–362. Bibcode:2007PPP...253..348M. doi:10.1016/j.palaeo.2007.06.008 . Retrieved 25 June 2024– via Elsevier Science Direct.
  35. ↑ Zachos, James C.; Dickens, Gerald R.; Zeebe, Richard E. (16 January 2008). "An early Cenozoic perspective on greenhouse warming and carbon-cycle dynamics". Nature . 451 (7176): 279–283. Bibcode:2008Natur.451..279Z. doi: 10.1038/nature06588 . ISSN   1476-4687. PMID   18202643.
  36. ↑ Burke, K. D.; Williams, J. W.; Chandler, M. A.; Haywood, A. M.; Lunt, D. J.; Otto-Bliesner, B. L. (26 December 2018). "Pliocene and Eocene provide best analogs for near-future climates". Proceedings of the National Academy of Sciences of the United States of America . 115 (52): 13288–13293. Bibcode:2018PNAS..11513288B. doi: 10.1073/pnas.1809600115 . ISSN   0027-8424. PMC   6310841 . PMID   30530685.
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