Articles | Volume 17, issue 1
Research article 18 Jan 2021
Research article | 18 Jan 2021
Exploring a link between the Middle Eocene Climatic Optimum and Neotethys continental arc flare-up
Annique van der Boon et al.
No articles found.
Carolien M. H. van der Weijst, Koen J. van der Laan, Francien Peterse, Gert-Jan Reichart, Francesca Sangiorgi, Stefan Schouten, Tjerk J. T. Veenstra, and Appy Sluijs
Clim. Past Discuss.,
Preprint under review for CPShort summary
The TEX86 proxy is often used by paleoceanographers to reconstruct past sea-surface temperatures. However, the origin of the TEX86 signal in marine sediments has been debated since the proxy was first proposed. In our paper, we show that TEX86 carries a mixed sea-surface and subsurface temperature signal, and should be calibrated accordingly. Using our 15 million year record, we subsequently show how a TEX86 subsurface temperature record can be used to inform us on past sea-surface temperatures.
Gerrit Müller, Jack J. Middelburg, and Appy Sluijs
Earth Syst. Sci. Data, 13, 3565–3575,Short summary
Rivers are major freshwater resources, connectors and transporters on Earth. As the composition of river waters and particles results from processes in their catchment, such as erosion, weathering, environmental pollution, nutrient and carbon cycling, Earth-spanning databases of river composition are needed for studies of these processes on a global scale. While extensive resources on water and nutrient composition exist, we provide a database of river particle composition.
Carolien Maria Hendrina van der Weijst, Josse Winkelhorst, Wesley de Nooijer, Anna von der Heydt, Gert-Jan Reichart, Francesca Sangiorgi, and Appy Sluijs
Clim. Past Discuss.,
Preprint under review for CPShort summary
A hypothesized link between Pliocene (5.3–2.5 million years ago) global climate and tropical thermocline depth is currently only backed up by data from the Pacific Ocean. In our paper, we present temperature, salinity and thermocline records from the tropical Atlantic Ocean. Surprisingly, the Pliocene thermocline evolution was remarkably different in the Atlantic and Pacific. We need to reevaluate the mechanisms that drive thermocline depth, and how these are tied to global climate change.
Xiaolong Zhou, Klaudia Kuiper, Jan Wijbrans, Katharina Boehm, and Pieter Vroon
Geochronology, 3, 273–297,Short summary
High-resolution geochronology is one of the key factors to predict volcanic eruptions. To build up a high-resolution geochronological framework, we reported 21 new high-precision eruption ages (40Ar / 39Ar) for a ~ 3.3 × 106-year-old volcanic field: Milos (Greece). In combination with geochemical information and eruption volumes from the volcanoes of Milos, the long-lived volcanic history could provide important clues for the prediction of volcanic eruptions.
Peter K. Bijl, Joost Frieling, Margot J. Cramwinckel, Christine Boschman, Appy Sluijs, and Francien Peterse
Clim. Past Discuss.,
Preprint under review for CPShort summary
We here use the latest insights for GDGT and dinocyst-based paleotemperature and paleoenvironmental reconstructions in Late Cretaceous –early Oligocene sediments from ODP Site 1172 (East Tasman Plateau, Australia). General trends in sea surface and air temperature are similar. We reconstruct strong river-runoff during the Paleocene-early Eocene, progressively becoming more marine thereafter, and gradual drying and increased wet/dry seasonality in the northward drifting hinterland.
Michiel Baatsen, Anna S. von der Heydt, Matthew Huber, Michael A. Kliphuis, Peter K. Bijl, Appy Sluijs, and Henk A. Dijkstra
Clim. Past, 16, 2573–2597,Short summary
Warm climates of the deep past have proven to be challenging to reconstruct with the same numerical models used for future predictions. We present results of CESM simulations for the middle to late Eocene (∼ 38 Ma), in which we managed to match the available indications of temperature well. With these results we can now look into regional features and the response to external changes to ultimately better understand the climate when it is in such a warm state.
Appy Sluijs, Joost Frieling, Gordon N. Inglis, Klaas G. J. Nierop, Francien Peterse, Francesca Sangiorgi, and Stefan Schouten
Clim. Past, 16, 2381–2400,Short summary
We revisit 15-year-old reconstructions of sea surface temperatures in the Arctic Ocean for the late Paleocene and early Eocene epochs (∼ 57–53 million years ago) based on the distribution of fossil membrane lipids of archaea preserved in Arctic Ocean sediments. We find that improvements in the methods over the past 15 years do not lead to different results. However, data quality is now higher and potential biases better characterized. Results confirm remarkable Arctic warmth during this time.
Gordon N. Inglis, Fran Bragg, Natalie J. Burls, Margot J. Cramwinckel, David Evans, Gavin L. Foster, Matthew Huber, Daniel J. Lunt, Nicholas Siler, Sebastian Steinig, Jessica E. Tierney, Richard Wilkinson, Eleni Anagnostou, Agatha M. de Boer, Tom Dunkley Jones, Kirsty M. Edgar, Christopher J. Hollis, David K. Hutchinson, and Richard D. Pancost
Clim. Past, 16, 1953–1968,Short summary
This paper presents estimates of global mean surface temperatures and climate sensitivity during the early Paleogene (∼57–48 Ma). We employ a multi-method experimental approach and show that i) global mean surface temperatures range between 27 and 32°C and that ii) estimates of
bulkequilibrium climate sensitivity (∼3 to 4.5°C) fall within the range predicted by the IPCC AR5 Report. This work improves our understanding of two key climate metrics during the early Paleogene.
Margot J. Cramwinckel, Lineke Woelders, Emiel P. Huurdeman, Francien Peterse, Stephen J. Gallagher, Jörg Pross, Catherine E. Burgess, Gert-Jan Reichart, Appy Sluijs, and Peter K. Bijl
Clim. Past, 16, 1667–1689,Short summary
Phases of past transient warming can be used as a test bed to study the environmental response to climate change independent of tectonic change. Using fossil plankton and organic molecules, here we reconstruct surface ocean temperature and circulation in and around the Tasman Gateway during a warming phase 40 million years ago termed the Middle Eocene Climatic Optimum. We find that plankton assemblages track ocean circulation patterns, with superimposed variability being related to temperature.
Carolien Maria Hendrina van der Weijst, Josse Winkelhorst, Anna von der Heydt, Gert-Jan Reichart, Francesca Sangiorgi, and Appy Sluijs
Clim. Past Discuss.,
Manuscript not accepted for further review
Gabriel J. Bowen, Brenden Fischer-Femal, Gert-Jan Reichart, Appy Sluijs, and Caroline H. Lear
Clim. Past, 16, 65–78,Short summary
Past climate conditions are reconstructed using indirect and incomplete geological, biological, and geochemical proxy data. We propose that such reconstructions are best obtained by statistical inversion of hierarchical models that represent how multi–proxy observations and calibration data are produced by variation of environmental conditions in time and/or space. These methods extract new information from traditional proxies and provide robust, comprehensive estimates of uncertainty.
Johan Vellekoop, Lineke Woelders, Appy Sluijs, Kenneth G. Miller, and Robert P. Speijer
Biogeosciences, 16, 4201–4210,Short summary
Our micropaleontological analyses on three cores from New Jersey (USA) show that the late Maastrichtian warming event (66.4–66.1 Ma), characterized by a ~ 4.0 °C warming of sea waters on the New Jersey paleoshelf, resulted in a disruption of phytoplankton communities and a stressed benthic ecosystem. This increased ecosystem stress during the latest Maastrichtian potentially primed global ecosystems for the subsequent mass extinction following the Cretaceous–Paleogene boundary impact.
Christopher J. Hollis, Tom Dunkley Jones, Eleni Anagnostou, Peter K. Bijl, Margot J. Cramwinckel, Ying Cui, Gerald R. Dickens, Kirsty M. Edgar, Yvette Eley, David Evans, Gavin L. Foster, Joost Frieling, Gordon N. Inglis, Elizabeth M. Kennedy, Reinhard Kozdon, Vittoria Lauretano, Caroline H. Lear, Kate Littler, Lucas Lourens, A. Nele Meckler, B. David A. Naafs, Heiko Pälike, Richard D. Pancost, Paul N. Pearson, Ursula Röhl, Dana L. Royer, Ulrich Salzmann, Brian A. Schubert, Hannu Seebeck, Appy Sluijs, Robert P. Speijer, Peter Stassen, Jessica Tierney, Aradhna Tripati, Bridget Wade, Thomas Westerhold, Caitlyn Witkowski, James C. Zachos, Yi Ge Zhang, Matthew Huber, and Daniel J. Lunt
Geosci. Model Dev., 12, 3149–3206,Short summary
The Deep-Time Model Intercomparison Project (DeepMIP) is a model–data intercomparison of the early Eocene (around 55 million years ago), the last time that Earth's atmospheric CO2 concentrations exceeded 1000 ppm. Previously, we outlined the experimental design for climate model simulations. Here, we outline the methods used for compilation and analysis of climate proxy data. The resulting climate
atlaswill provide insights into the mechanisms that control past warm climate states.
Sabrina van de Velde, Elisabeth L. Jorissen, Thomas A. Neubauer, Silviu Radan, Ana Bianca Pavel, Marius Stoica, Christiaan G. C. Van Baak, Alberto Martínez Gándara, Luis Popa, Henko de Stigter, Hemmo A. Abels, Wout Krijgsman, and Frank P. Wesselingh
Biogeosciences, 16, 2423–2442,
Ilja J. Kocken, Margot J. Cramwinckel, Richard E. Zeebe, Jack J. Middelburg, and Appy Sluijs
Clim. Past, 15, 91–104,Short summary
Marine organic carbon burial could link the 405 thousand year eccentricity cycle in the long-term carbon cycle to that observed in climate records. Here, we simulate the response of the carbon cycle to astronomical forcing. We find a strong 2.4 million year cycle in the model output, which is present as an amplitude modulator of the 405 and 100 thousand year eccentricity cycles in a newly assembled composite record.
Michiel Baatsen, Anna S. von der Heydt, Matthew Huber, Michael A. Kliphuis, Peter K. Bijl, Appy Sluijs, and Henk A. Dijkstra
Clim. Past Discuss.,
Revised manuscript not acceptedShort summary
The Eocene marks a period where the climate was in a hothouse state, without any continental-scale ice sheets. Such climates have proven difficult to reproduce in models, especially their low temperature difference between equator and poles. Here, we present high resolution CESM simulations using a new geographic reconstruction of the middle-to-late Eocene. The results provide new insights into a period for which knowledge is limited, leading up to a transition into the present icehouse state.
Helen M. Beddow, Diederik Liebrand, Douglas S. Wilson, Frits J. Hilgen, Appy Sluijs, Bridget S. Wade, and Lucas J. Lourens
Clim. Past, 14, 255–270,Short summary
We present two astronomy-based timescales for climate records from the Pacific Ocean. These records range from 24 to 22 million years ago, a time period when Earth was warmer than today and the only land ice was located on Antarctica. We use tectonic plate-pair spreading rates to test the two timescales, which shows that the carbonate record yields the best timescale. In turn, this implies that Earth’s climate system and carbon cycle responded slowly to changes in incoming solar radiation.
Joost Frieling, Gert-Jan Reichart, Jack J. Middelburg, Ursula Röhl, Thomas Westerhold, Steven M. Bohaty, and Appy Sluijs
Clim. Past, 14, 39–55,Short summary
Past periods of rapid global warming such as the Paleocene–Eocene Thermal Maximum are used to study biotic response to climate change. We show that very high peak PETM temperatures in the tropical Atlantic (~ 37 ºC) caused heat stress in several marine plankton groups. However, only slightly cooler temperatures afterwards allowed highly diverse plankton communities to bloom. This shows that tropical plankton communities may be susceptible to extreme warming, but may also recover rapidly.
Michiel Baatsen, Douwe J. J. van Hinsbergen, Anna S. von der Heydt, Henk A. Dijkstra, Appy Sluijs, Hemmo A. Abels, and Peter K. Bijl
Clim. Past, 12, 1635–1644,Short summary
One of the major difficulties in modelling palaeoclimate is constricting the boundary conditions, causing significant discrepancies between different studies. Here, a new method is presented to automate much of the process of generating the necessary geographical reconstructions. The latter can be made using various rotational frameworks and topography/bathymetry input, allowing for easy inter-comparisons and the incorporation of the latest insights from geoscientific research.
Niels A. G. M. van Helmond, Appy Sluijs, Nina M. Papadomanolaki, A. Guy Plint, Darren R. Gröcke, Martin A. Pearce, James S. Eldrett, João Trabucho-Alexandre, Ireneusz Walaszczyk, Bas van de Schootbrugge, and Henk Brinkhuis
Biogeosciences, 13, 2859–2872,Short summary
Over the past decades large changes have been observed in the biogeographical dispersion of marine life resulting from climate change. To better understand present and future trends it is important to document and fully understand the biogeographical response of marine life during episodes of environmental change in the geological past. Here we investigate the response of phytoplankton, the base of the marine food web, to a rapid cold spell, interrupting greenhouse conditions during the Cretaceous.
N. A. G. M. van Helmond, A. Sluijs, J. S. Sinninghe Damsté, G.-J. Reichart, S. Voigt, J. Erbacher, J. Pross, and H. Brinkhuis
Clim. Past, 11, 495–508,Short summary
Based on the chemistry and microfossils preserved in sediments deposited in a shallow sea, in the current Lower Saxony region (NW Germany), we conclude that changes in Earth’s orbit around the Sun led to enhanced rainfall and organic matter production. The additional supply of organic matter, depleting oxygen upon degradation, and freshwater, inhibiting the mixing of oxygen-rich surface waters with deeper waters, caused the development of oxygen-poor waters about 94 million years ago.
B. S. Slotnick, V. Lauretano, J. Backman, G. R. Dickens, A. Sluijs, and L. Lourens
Clim. Past, 11, 473–493,
A. Sluijs, L. van Roij, G. J. Harrington, S. Schouten, J. A. Sessa, L. J. LeVay, G.-J. Reichart, and C. P. Slomp
Clim. Past, 10, 1421–1439,
L. Contreras, J. Pross, P. K. Bijl, R. B. O'Hara, J. I. Raine, A. Sluijs, and H. Brinkhuis
Clim. Past, 10, 1401–1420,
J. S. Eldrett, D. R. Greenwood, M. Polling, H. Brinkhuis, and A. Sluijs
Clim. Past, 10, 759–769,
I. G. M. Wientjes, R. S. W. Van de Wal, G. J. Reichart, A. Sluijs, and J. Oerlemans
The Cryosphere, 5, 589–601,
Related subject area
Subject: Carbon Cycle | Archive: Terrestrial Archives | Timescale: CenozoicAlluvial record of an early Eocene hyperthermal within the Castissent Formation, the Pyrenees, SpainPaleoenvironmental response of midlatitudinal wetlands to Paleocene–early Eocene climate change (Schöningen lignite deposits, Germany)Synchronizing early Eocene deep-sea and continental records – cyclostratigraphic age models for the Bighorn Basin Coring Project drill coresEnvironmental impact and magnitude of paleosol carbonate carbon isotope excursions marking five early Eocene hyperthermals in the Bighorn Basin, WyomingFossil plant stomata indicate decreasing atmospheric CO2 prior to the Eocene–Oligocene boundaryModulation of Late Cretaceous and Cenozoic climate by variable drawdown of atmospheric pCO2 from weathering of basaltic provinces on continents drifting through the equatorial humid belt
Louis Honegger, Thierry Adatte, Jorge E. Spangenberg, Jeremy K. Caves Rugenstein, Miquel Poyatos-Moré, Cai Puigdefàbregas, Emmanuelle Chanvry, Julian Clark, Andrea Fildani, Eric Verrechia, Kalin Kouzmanov, Matthieu Harlaux, and Sébastien Castelltort
Clim. Past, 16, 227–243,Short summary
A geochemical study of a continental section reveals a rapid global warming event (hyperthermal U), occurring ca. 50 Myr ago, only described until now in marine sediment cores. Documenting how the Earth system responded to rapid climatic shifts provides fundamental information to constrain climatic models. Our results suggest that continental deposits can be high-resolution recorders of these warmings. They also give an insight on the climatic conditions occurring during at the time.
Katharina Methner, Olaf Lenz, Walter Riegel, Volker Wilde, and Andreas Mulch
Clim. Past, 15, 1741–1755,Short summary
We describe the presence of a carbon isotope excursion (CIE) in Paleogene lignites (Schöningen, DE) and assess paleoenvironmental changes in midlatitudinal late Paleocene–early Eocene peat mire records along the paleo-North Sea coast (Schöningen, Cobham, Vasterival). These records share major characteristics of a reduced CIE (~ -1.3 ‰) in terms of bulk organic matter, increased fire activity (pre-CIE), minor plant species changes, and drowning of near-coastal mires during the CIE.
Thomas Westerhold, Ursula Röhl, Roy H. Wilkens, Philip D. Gingerich, William C. Clyde, Scott L. Wing, Gabriel J. Bowen, and Mary J. Kraus
Clim. Past, 14, 303–319,Short summary
Here we present a high-resolution timescale synchronization of continental and marine deposits for one of the most pronounced global warming events, the Paleocene–Eocene Thermal Maximum, which occurred 56 million years ago. New high-resolution age models for the Bighorn Basin Coring Project (BBCP) drill cores help to improve age models for climate records from deep-sea drill cores and for the first time point to a concurrent major change in marine and terrestrial biota 54.25 million years ago.
Hemmo A. Abels, Vittoria Lauretano, Anna E. van Yperen, Tarek Hopman, James C. Zachos, Lucas J. Lourens, Philip D. Gingerich, and Gabriel J. Bowen
Clim. Past, 12, 1151–1163,Short summary
Ancient greenhouse warming episodes are studied in river floodplain sediments in the western interior of the USA. Paleohydrological changes of four smaller warming episodes are revealed to be the opposite of those of the largest, most-studied event. Carbon cycle tracers are used to ascertain whether the largest event was a similar event but proportional to the smaller ones or whether this event was distinct in size as well as in carbon sourcing, a question the current work cannot answer.
Margret Steinthorsdottir, Amanda S. Porter, Aidan Holohan, Lutz Kunzmann, Margaret Collinson, and Jennifer C. McElwain
Clim. Past, 12, 439–454,Short summary
Our manuscript "Fossil plant stomata indicate decreasing atmospheric CO2 prior to the Eocene–Oligocene boundary" reports that ~ 40 % decrease in pCO2 preceded the large shift in marine oxygen isotope records that characterizes the Eocene–Oliogocene climate transition. The results endorse the theory that pCO2 drawdown was the main forcer of the Eocene–Oligocene climate change, and a "tipping point" was reached in the latest Eocene, triggering the plunge of the Earth System into icehouse conditions.
D. V. Kent and G. Muttoni
Clim. Past, 9, 525–546,
Allen, M. B. and Armstrong, H. A.: Arabia – Eurasia collision and the forcing of mid-Cenozoic global cooling, Palaeogeogr. Palaeocl., 265, 52–58, https://doi.org/10.1016/j.palaeo.2008.04.021, 2008.
Amini, B. and Amini Chehragh, M. R.: Geological Map of Iran 1:100.000 Series Sheet 2555 – Kajan, Geological Survey of Iran, Tehran, 2001.
Amini Chehragh, M. R. and Ghalamghash, J.: Geological Map of Iran 1:100.000 Series Sheet 7162 – Meyamey, Geological Survey of Iran, Tehran, available at: https://shop.geospatial.com/product/03-IRAB-367, last access: 11 January 2021.
Asiabanha, A. and Foden, J.: Post-collisional transition from an extensional volcano-sedimentary basin to a continental arc in the Alborz Ranges, N-Iran, Lithos, 148, 98–111, https://doi.org/10.1016/j.lithos.2012.05.014, 2012.
Babakhani, A. R., Nazer, N. H., and Amidi, M.: Geological Map of Iran 1:100.000 Series Sheet 5567 – Lahrud, (5567), Geological Survey of Iran, Tehran, 1991.
Ballato, P., Uba, C. E., Landgraf, A., Strecker, M. R., Sudo, M., Stockli, D. F., Friedrich, A., and Tabatabaei, S. H.: Arabia-Eurasia continental collision: Insights from late Tertiary foreland-basin evolution in the Alborz Mountains, northern Iran, Geol. Soc. Am. Bull., 123, 106–131, https://doi.org/10.1130/B30091.1, 2011.
Beniamovski, V. N., Alekseev, A. S., Ovechkina, M. N., and Oberhänsli, H.: Middle to upper Eocene dysoxic-anoxic Kuma Formation (northeast Peri-Tethys): Biostratigraphy and paleoenvironments, Geol. Soc. Am. Spec. Pap., 369, 95–112, 2003.
Berberian, M. and King, G. C. P. C. P.: Towards a paleogeography and tectonic evolution of Iran, Can. J. Earth Sci., 18, 1764–1766, https://doi.org/10.1139/e81-163, 1981.
Bijl, P. K., Houben, A. J. P. P., Schouten, S., Bohaty, S. M., Sluijs, A., Reichart, G.-J. J., Sinninghe Damsté, J. S., Brinkhuis, H., Damsté, J. S. S., and Brinkhuis, H.: Transient middle eocene atmospheric CO2 and temperature variations, Science, 330, 819–821, https://doi.org/10.1126/science.1193654, 2010.
Bohaty, S. M. and Zachos, J. C.: Significant Southern Ocean warming event in the late middle Eocene, Geology, 31, 1017–1020, 2003.
Bohaty, S. M., Zachos, J. C., Florindo, F., and Delaney, M. L.: Coupled greenhouse warming and deep-sea acidification in the middle Eocene, Paleoceanography, 24, 1–16, https://doi.org/10.1029/2008PA001676, 2009.
Boscolo Galazzo, F., Giusberti, L., Luciani, V., and Thomas, E.: Paleoenvironmental changes during the Middle Eocene Climatic Optimum (MECO) and its aftermath: The benthic foraminiferal record from the Alano section (NE Italy), Palaeogeogr. Palaeocl., 378, 22–35, https://doi.org/10.1016/j.palaeo.2013.03.018, 2013.
Boscolo Galazzo, F., Thomas, E., Pagani, M., Warren, C., Luciani, V., and Giusberti, L.: The middle Eocene climatic optimum (MECO): A multiproxy record of paleoceanographic changes in the southeast Atlantic (ODP Site 1263, Walvis Ridge), Paleoceanography, 29, 1143–1161, https://doi.org/10.1002/2014PA002670, 2014.
Cramwinckel, M. J., Huber, M., Kocken, I. J., Agnini, C., Bijl, P. K., Bohaty, S. M., Frieling, J., Goldner, A., Hilgen, F. J., Kip, E. L., Peterse, F., Van Der Ploeg, R., Röhl, U., Schouten, S., and Sluijs, A.: Synchronous tropical and polar temperature evolution in the Eocene, Nature, 559, 382–386, https://doi.org/10.1038/s41586-018-0272-2, 2018.
Cramwinckel, M. J., van der Ploeg, R., Bijl, P. K., Peterse, F., Bohaty, S. M., Röhl, U., Schouten, S., Middelburg, J. J., and Sluijs, A.: Harmful algae and export production collapse in the equatorial Atlantic during the zenith of Middle Eocene Climatic Optimum warmth, Geology, 47, 247–250, 2019.
Davoudzadeh, M., Lammerer, B., and Weber-Diefenbach, K.: Paleogeography, Stratigraphy and tectonics of the Tertiary of Iran, Neues Jahrb. fur Geol. und Palaontologie, Abhandlungen 205, 33–67, 1997.
De Silva, S. L., Riggs, N. R., and Barth, A. P.: Quickening the pulse: Fractal tempos in continental arc magmatism, Elements, 11, 113–118, https://doi.org/10.2113/gselements.11.2.113, 2015.
Ducea, M. N. and Barton, M. D.: Igniting flare-up events in Cordilleran arcs, Geology, 35, 1047–1050, https://doi.org/10.1130/G23898A.1, 2007.
Ducea, M. N., Paterson, S. R., and DeCelles, P. G.: High-volume magmatic events in subduction systems, Elements, 11, 99–104, https://doi.org/10.2113/gselements.11.2.99, 2015.
Edgar, K. M., Bohaty, S. M., Gibbs, S. J., Sexton, P. F., Norris, R. D., and Wilson, P. A.: Symbiont “bleaching” in planktic foraminifera during the Middle Eocene Climatic Optimum, Geology, 41, 15–18, https://doi.org/10.1130/G33388.1, 2013.
Emami, M. H.: Geological Quadrangle Map of Iran, 1:250.000 scale, Sheet E6, Qom, Geological Survey of Iran, Tehran, 1981.
Ganino, C. and Arndt, N. T.: Climate changes caused by degassing of sediments during the emplacement of large igneous provinces, Geology, 37, 323–326, https://doi.org/10.1130/G25325A.1, 2009.
Ghalamghash, J., Fonoudi, M., and Mehrpartou, M.: Geological Map of Iran 1:100.000 Series Sheet 6060 – Saveh, Geological Survey of Iran, Tehran, 1998a.
Ghalamghash, J., Babakhani, A. R., Bahroudi, A., and Fonoudi, M.: Geological Map of Iran 1:100.000 Series Sheet 6158 – Kahak, Geological Survey of Iran, Tehran, 1998b.
Glaus, M.: Die Geologie des Gebietes nordlich des Kandevan-Passes (Zentral-Elburz), Iran, PhD thesis, Nr. 3768, ETH, Zurich, 1965.
Hadjian, J., Amini, B., and Amini Chehragh, M. R.: Geological Map of Iran 1:100.000 Series Sheet 6059 – Tafreshm, Geological Survey of Iran, Tehran, 1999.
Henehan, M. J., Edgar, K. M., Foster, G. L., Penman, D. E., Hull, P. M., Greenop, R., Anagnostou, E., and Pearson, P. N.: Revisiting the Middle Eocene Climatic Optimum “Carbon Cycle Conundrum” with new estimates of atmospheric pCO2 from boron isotopes, Paleoceanogr. Paleocl., 35: e2019PA003713, https://doi.org/10.1029/2019PA003713, 2020.
Hirayama, K., Samimi, M., Zahedi, M., and Hushmand-Zadeh, A.: Geology of the Tarom district, western part (Zanjan area, northwest Iran), Geological Survey of Iran, Tehran, 1966.
Iwao, S. and Hushmand-Zadeh, A.: Stratigraphy and Petrology of the Low-Grade Regionally Metamorphosed rocks of the Eocene Formation in the Alborz Range, North of Tehran, Iran, J. Japanese Assoc. Mineral. Petrol. Econ. Geol., 65, 265–285, 1971.
Jafarian, M. B.: Geological Map of Iran Series Sheet 6860 – Kalateh, Geological Survey of Iran, Tehran, avalable at: https://shop.geospatial.com/product/03-IRAB-354, last access: 11 January 2021.
Jay, A. E. and Widdowson, M.: Stratigraphy, structure and volcanology of the SE Deccan continental flood basalt province: implications for eruptive extent and volumes, J. Geol. Soc. London., 165, 177–188, https://doi.org/10.1144/0016-76492006-062, 2008.
Kargaranbafghi, F. and Neubauer, F.: Tectonic forcing to global cooling and aridification at the Eocene-Oligocene transition in the Iranian plateau, Global Planet. Change, 171, 248–254, https://doi.org/10.1016/j.gloplacha.2017.12.012, 2018.
Kholghi Khasraghi, M. H.: Geological Map of Iran 1:100.000 Series Sheet 5365, Saein Qaleh, Geological Survey of Iran, Tehran, 1994.
Kuiper, K. F., Deino, A., Hilgen, F. J., Krijgsman, W., Renne, P. R., and Wijbrans, J. R.: Synchronizing rock clocks of earth history, Science, 320, 500–504, https://doi.org/10.1126/science.1154339, 2008.
Lee, C. A. and Lackey, J. S.: Global Continental Arc Flare-ups and Their Relation to Long-Term Greenhouse Conditions, Elements, 11, 125–130, https://doi.org/10.2113/gselements.11.2.125, 2015.
Lee, C.-T. A., Shen, B., Slotnick, B. S., Liao, K., Dickens, G. R., Yokoyama, Y., Lenardic, A., Dasgupta, R., Jellinek, M., Lackey, J. S., Schneider, T., and Tice, M. M.: Continental arc – island arc fluctuations, growth of crustal carbonates, and long-term climate change, Geosphere, 9, 21–36, https://doi.org/10.1130/GES00822.1, 2013.
Marty, B. and Tolstikhin, I. N.: CO2 fluxes from mid-ocean ridges, arcs and plumes, Chem. Geol., 145, 233–248, 1998.
McKenzie, N. R., Horton, B. K., Loomis, S. E., Stockli, D. F., Planavsky, N. J., and Lee, C. A. C.-T. A. C. A. C.-T. A. C. A.: Continental arc volcanism as the principal driver of icehouse-greenhouse variability, Science, 352, 444–447, https://doi.org/10.1126/science.aad5787, 2016.
Min, K., Mundil, R., Renne, P. R., and Ludwig, K. R.: A test for systematic errors in 40Ar∕39Ar geochronology through comparison with U/Pb analysis of a 1.1-Ga rhyolite, Geochim. Cosmochim. Acta, 64, 73–98, https://doi.org/10.1016/S0016-7037(99)00204-5, 2000.
Moghadam, H. S., Li, X.-H., Ling, X.-X., Santos, J. F., Stern, R. J., Li, Q.-L., and Ghorbani, G.: Eocene Kashmar granitoids (NE Iran): Petrogenetic constraints from U-Pb zircon geochronology and isotope geochemistry, Lithos, 216–217, 118–135, https://doi.org/10.1016/j.lithos.2014.12.012, 2015.
Moghadam, H. S., Rossetti, F., Lucci, F., Chiaradia, M., Gerdes, A., Martinez, M. L., Ghorbani, G., and Nasrabady, M.: The calc-alkaline and adakitic volcanism of the Sabzevar structural zone (NE Iran): Implications for the Eocene magmatic flare-up in Central Iran, Lithos, 248–251, 517–535, https://doi.org/10.1016/j.lithos.2016.01.019, 2016.
Mohajjel Kafshdouz, M. and Khodabandeh, A. A.: Geological Map of Iran 1:100.000 Series Sheet 7335 – Bardsir, Geological Survey of Iran, Tehran, 1992.
Monster, M.: Multi-method palaeointensity data of the geomagnetic field during the past 500 kyrs from European volcanoes, UU Dept. of Earth Sciences, Utrecht, 2016.
Moritz, R., Rezeau, H., Ovtcharova, M., Tayan, R., Melkonyan, R., Hovakimyan, S., Ramazanov, V., Selby, D., Ulianov, A., Chiaradia, M., and Putlitz, B.: Long-lived, stationary magmatism and pulsed porphyry systems during Tethyan subduction to post-collision evolution in the southernmost Lesser Caucasus, Armenia and Nakhitchevan, Gondwana Res., 37, 465–503, https://doi.org/10.1016/j.gr.2015.10.009, 2016.
Morley, C. K., Kongwung, B., Julapour, A. A. A., Abdolghafourian, M., Hajian, M., Waples, D., Warren, J., Otterdoom, H., Srisuriyon, K., and Kazemi, H.: Structural development of a major late Cenozoic basin and transpressional belt in central Iran: The Central Basin in the Qom-Saveh area, Geosphere, 5, 325–362, https://doi.org/10.1130/GES00223.1, 2009.
Pang, K.-N., Chung, S.-L., Zarrinkoub, M. H., Khatib, M. M., Mohammadi, S. S., Chiu, H.-Y., Chu, C.-H., Lee, H.-Y., and Lo, C.-H.: Eocene–Oligocene post-collisional magmatism in the Lut–Sistan region, eastern Iran: Magma genesis and tectonic implications, Lithos, 180–181, 234–251, https://doi.org/10.1016/j.lithos.2013.05.009, 2013.
Radfar, J., Kohansal, R., and S. Zolfagh: Geological Map of Iran 1:100.000 Series Sheet 6455 – Kuhpayeh, Geological Survey of Iran, Tehran, 2002.
Sahakyan, L., Bosch, D., Sosson, M., Avagyan, A., Galoyan, G. H., Rolland, Y., Bruguier, O., Stepanyan, Z. H., Galland, B., Vardanyan, S., and Bataillon, P. E.: Geochemistry of the Eocene magmatic rocks from the Lesser Caucasus area (Armenia): evidence of a subduction geodynamic environment, Geol. Soc. Spec. Publ., 428, 73–98, https://doi.org/10.1144/SP428.12, 2016.
Seidov, A. G. and Alizade, K. A.: The formation and mineralogy of bentonites in Azerbaijan, Clay Miner., 6, 157–166, 1966.
Shafaii Moghadam, H., Li, X.-H., Ling, X.-X., Santos, J. F., Stern, R. J., Li, Q.-L., and Ghorbani, G.: Eocene Kashmar granitoids (NE Iran): Petrogenetic constraints from U−Pb zircon geochronology and isotope geochemistry, Lithos, 216–217, 118–135, https://doi.org/10.1016/j.lithos.2014.12.012, 2015.
Shafaii Moghadam, H., Li, Q. L., Li, X. H., Stern, R. J., Levresse, G., Santos, J. F., Lopez Martinez, M., Ducea, M. N., Ghorbani, G., and Hassannezhad, A.: Neotethyan Subduction Ignited the Iran Arc and Backarc Differently, J. Geophys. Res.-Sol. Ea., 125, 1–30, https://doi.org/10.1029/2019JB018460, 2020.
Sieber, N.: Zur Geologie des Gebietes südlich des Taleghan-Tales Zentral-Elburz (Iran), PhD thesis, Nr. 4482, ETH Zurich, https://doi.org/10.3929/ethz-a-000085644, 1970.
Simon, J. I., Renne, P. R., and Mundil, R.: Implications of pre-eruptive magmatic histories of zircons for U−Pb geochronology of silicic extrusions, Earth Planet. Sc. Lett., 266, 182–194, https://doi.org/10.1016/j.epsl.2007.11.014, 2008.
Sluijs, A., Zeebe, R. E., Bijl, P. K., and Bohaty, S. M.: A middle Eocene carbon cycle conundrum, Nat. Geosci., 6, 429–434, https://doi.org/10.1038/ngeo1807, 2013.
Stöcklin, J.: Northern Iran: Alborz Mountains, Geol. Soc. Spec. Publ., 4, 213–234, https://doi.org/10.1144/GSL.SP.2005.004.01.12, 1974.
Tobin, T. S., Bitz, C. M., and Archer, D.: Modeling climatic effects of carbon dioxide emissions from Deccan Traps volcanic eruptions around the Cretaceous – Paleogene boundary, Palaeogeogr. Palaeocl., 478, 139–148, https://doi.org/10.1016/j.palaeo.2016.05.028, 2017.
van der Boon, A.: From Peri-Tethys to Paratethys: Basin restriction and anoxia in central Eurasia linked to volcanic belts in Iran, Utrecht University, the Netherlands, 2017.
van der Boon, A., Kuiper, K. F., Villa, G., Renema, W., Meijers, M. J. M. M., Langereis, C. G., Aliyeva, E., and Krijgsman, W.: Onset of Maikop sedimentation and cessation of Eocene arc volcanism in the Talysh Mountains, Azerbaijan, Geol. Soc. Spec. Publ., 428, 145–169, https://doi.org/10.1144/sp428.3, 2017.
van der Ploeg, R., Selby, D., Cramwinckel, M. J., Li, Y., Bohaty, S. M., Middelburg, J. J., and Sluijs, A.: Middle Eocene greenhouse warming facilitated by diminished weathering feedback, Nat. Commun., 9, 2877, https://doi.org/10.1038/s41467-018-05104-9, 2018.
Verdel, C.: I. Cenozoic geology of Iran: an integrated study of extensional tectonics and related volcanism II. Ediacaran stratigraphy of the North American Cordillera: new observations from Eastern California and Northern Utah, Dissertation (PhD), California Institute of Technology, https://doi.org/10.7907/4KPY-X114, 2009.
Verdel, C., Wernicke, B. P., Hassanzadeh, J., and Guest, B.: A Paleogene extensional arc flare-up in Iran, Tectonics, 30, 1–20, https://doi.org/10.1029/2010TC002809, 2011.
Vermeesch, P.: On the visualisation of detrital age distributions, Chem. Geol., 312–313, 190–194, https://doi.org/10.1016/j.chemgeo.2012.04.021, 2012.
Vincent, S. J., Allen, M. B., Ismail-Zadeh, A. D., Flecker, R., Foland, K. A., and Simmons, M. D.: Insights from the Talysh of Azerbaijan into the Paleogene evolution of the South Caspian region, Geol. Soc. Am. Bull., 117, 1513–1533, https://doi.org/10.1130/B25690.1, 2005.
Wignall, P. B., Sun, Y., Bond, D. P. G. G., Izon, G., Newton, R. J., Védrine, S., Widdowson, M., Ali, J. R., Lai, X., Jiang, H., Cope, H., and Bottrell, S. H.: Volcanism, Mass Extinction, and Carbon Isotope Fluctuations in the Middle Permian of China, Science, 324, 1179–1182, https://doi.org/10.1126/science.1171956, 2009.
Witkowski, J., Bohaty, S. M., McCartney, K., and Harwood, D. M.: Enhanced siliceous plankton productivity in response to middle Eocene warming at Southern Ocean ODP Sites 748 and 749, Palaeogeogr. Palaeocl., 326–328, 78–94, https://doi.org/10.1016/j.palaeo.2012.02.006, 2012.
40.5 million years ago, Earth's climate warmed, but it is unknown why. Enhanced volcanism has been suggested, but this has not yet been tied to a specific region. We explore an increase in volcanism in Iran. We dated igneous rocks and compiled ages from the literature. We estimated the volume of igneous rocks in Iran in order to calculate the amount of CO2 that could have been released due to enhanced volcanism. We conclude that an increase in volcanism in Iran is a plausible cause of warming.
40.5 million years ago, Earth's climate warmed, but it is unknown why. Enhanced volcanism has...