Mineralogical evidence for warm and dry climatic conditions in the Neo-Tethys (eastern Turkey) during the middle Eocene

Rêgo, Eric Siciliano; Jovane, Luigi; Hein, James R.; Sant’anna, Lucy Gomes; Giorgioni, M.; Rodelli, Daniel; Özcan, Ercan

doi:10.1016/j.palaeo.2018.04.007

Cited by 21 publications

(22 citation statements)

References 72 publications

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“…Minerals abundance is from ref. 16 , note that quartz and calcite are respect to bulk minerals abundance, whereas clays are respect to bulk phyllosilicates abundance. The intervals I, II, and III represent the climatic phases described in ref.…”

Section: Resultsmentioning

confidence: 99%

Carbon cycle instability and orbital forcing during the Middle Eocene Climatic Optimum

Giorgioni

Jovane

Rêgo

et al. 2019

Sci Rep

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The Middle Eocene Climatic Optimum (MECO) is a global warming event that occurred at about 40 Ma. In comparison to the most known global warming events of the Paleogene, the MECO has some peculiar features that make its interpretation controversial. The main peculiarities of the MECO are a duration of ~500 kyr and a carbon isotope signature that varies from site to site. Here we present new carbon and oxygen stable isotopes records (δ 13 C and δ 18 O) from three foraminiferal genera dwelling at different depths throughout the water column and the sea bottom during the middle Eocene, from eastern Turkey. We document that the MECO is related to major oceanographic and climatic changes in the Neo-Tethys and also in other oceanic basins. The carbon isotope signature of the MECO is difficult to interpret because it is highly variable from site to site. We hypothesize that such δ 13 C signature indicates highly unstable oceanographic and carbon cycle conditions, which may have been forced by the coincidence between a 400 kyr and a 2.4 Myr orbital eccentricity minimum. Such forcing has been also suggested for the Cretaceous Oceanic Anoxic Events, which resemble the MECO event more than the Cenozoic hyperthermals.

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Section: Resultsmentioning

confidence: 99%

Carbon cycle instability and orbital forcing during the Middle Eocene Climatic Optimum

Giorgioni

Jovane

Rêgo

et al. 2019

Sci Rep

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“…We emphasize the distribution and zonal significance of LBF, described from 17 levels in Bartonian-earliest Priabonian interval based solely on descriptions from the loose specimens. This study follows the works of Rodelli et al (2018) and Rego et al (2018) from the same section, having presented a magnetobiostratigarphic framework and environmental conditions, and Özcan et al (2006), having presented the most comprehensive LBF data from the Kırkgeçit Formation in the same area with the Baskil section.…”

Section: Introductionmentioning

confidence: 84%

Integrated biostratigraphy of the middle to upper Eocene Kırkgeçit Formation (Baskil section, Elazığ, eastern Turkey): larger benthic foraminiferal perspective

et al. 2019

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The Baskil section, located to the west of Elazığ in eastern Turkey, represents deep-marine facies of the Eocene Kırkgeçit Formation, deposited in a wide spectrum of environmental conditions ranging from shelf to basin. The 390-m-thick sequence was deposited at bathyal depths in the Tethys, at the edge of the subsiding Anatolide-Tauride plate and is highly promising for an integrated study of Bartonian to earliest Priabonian mid-latitude neritic and deep-marine biota. The section contains numerous allochthonous limestone beds, characterized either by turbidites or debris flows with resedimented larger benthic foraminifera (LBF). The section spans the planktonic foraminiferal Zones E10/11 to E14, the calcareous nannofossil zones NP15-NP18, shallow benthic zones (SBZ) SBZ16/17 to SBZ18A, including orthophragminid (OZ) zones OZ12-OZ14. The Bartonian-Priabonian boundary is placed at NP17/18 boundary by the lowest occurrence of Chiasmolithus oamaruensis, which lies within Subchron C17n.1n and Zone SBZ18A. The LBF, obtained as loose specimens from 17 turbiditic and debris flow beds, are characterized predominantly by 21 orthophragminid lineages and 13 nummulitid species as well as some other stratigraphically diagnostic genera. Most of the orthophragminid lineages straddle the Bartonian-Priabonian boundary, whereas Orbitoclypeus douvillei and Discocyclina pulcra appear to be the only orthophragminids confined to SBZ17 at its upper range. The Nummulites fabianii-lineage first appearing in zones E12 and NP16 in the Bartonian shows a well-documented evolution of the embryon, and is referred to Nummulites garganicus in the Bartonian, whereas its successor Nummulites hormoensis straddles the Bartonian/Priabonian boundary. The first appearances of N. hormoensis and Heterostegina armenica as well as the last occurrences of Nummulites ptukhiani and Assilina exponens in the section are almost coeval and are utilized to mark SBZ17-18 boundary. The first appearance of the H. armenica-lineage is recorded in zones E14 and upper part of NP17. Two important species, Chapmanina gassinensis and Silvestriella tetraedra, have been first recorded in SBZ18A just above the Bartonian-Priabonian boundary. Thus, the transition of N. garganicus to N. hormoensis, the first appearances of H. armenica, C. gassinensis and S. tetraedra as well as the last occurrences of N. ptukhiani, Assilina exponens, Discocyclina pulcra and Orbitoclypeus douvillei, all across the SBZ17-18 boundary or within the SBZ18A, appear to be the most useful bioevents in the transition from the Bartonian to the Priabonian in shallow-marine realms.

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“…Savian et al, 2014Savian et al, , 2016. Rego et al (2018) presented mineralogical evidences that the MECO period in the Baskil Section was characterized by a warm and dry climate, while it was colder and wetter before and after the MECO. A dry climate suggests that chemical alteration of the source rocks was limited, nd that most of the sediments coming into the basin was transported by wind.…”

Section: Paleoenvironmental Considerationsmentioning

confidence: 99%

“…CAE-3 is considered to be an hyperthermal event happening at ~41.5 Ma by Westerhold and Rhöl (2013) and is interpreted as a sudden deepening of the CCD (calcite compensation depth) (Edgar et al, 2007), and considered by some authors to be related to the formation of modest-size ice sheets at the poles (Lyle et al, 2005). A colder climate, coupled with high humidity in the region (Rego et al, 2018) might explain why the CAE-3 event in the Baskil section is represented by an increase of high coercivity magnetic minerals, as the source rock was undergoing chemical alteration, with the consequent oxidation and hydration of primary magnetite to form hematite and/or gohetite. The second event at ~50 msl can be dated between 41.34 and 41.20 Ma, and it is not yet been described in literature.…”

Section: Paleoenvironmental Considerationsmentioning

confidence: 99%

“…Water stratification could effectively also explain the increased concentration of biogenic magnetite, as water masses with high dissolved iron content could be concentrated in a limited depth, leading to a relative increase of Fe availability and thus effectively fertilizing the area. Iron fertilization is unlikely to be related to an increase of local input of dissolved Fe, since, according toRego et al (2018), the MECO in this region was a dry period, therefore limiting the chemical alteration of source rocks and consequently limiting the extraction of Fe from the minerals.…”

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Paleoceanographic variations through the study of rock magnetic properties: biogenic magnetite as a new paleoenvironmental indicator

Rodelli¹

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Mineralogical evidence for warm and dry climatic conditions in the Neo-Tethys (eastern Turkey) during the middle Eocene

Cited by 21 publications

References 72 publications

Carbon cycle instability and orbital forcing during the Middle Eocene Climatic Optimum

Carbon cycle instability and orbital forcing during the Middle Eocene Climatic Optimum

Integrated biostratigraphy of the middle to upper Eocene Kırkgeçit Formation (Baskil section, Elazığ, eastern Turkey): larger benthic foraminiferal perspective

Paleoceanographic variations through the study of rock magnetic properties: biogenic magnetite as a new paleoenvironmental indicator

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