Pliocene switch in orbital‐scale carbon cycle/climate dynamics

Turner, S. Kirtland

doi:10.1002/2014pa002651

Cited by 34 publications

(51 citation statements)

References 71 publications

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“…A similar temporal lag is also recorded in the coccolithophore‐related productivity records in the NW Pacific Ocean during the past 500 kyr [ Bordiga et al , ] and in biogenic opal accumulation records from the eastern and central equatorial Pacific [ Calvo et al , ; Hayes et al , ]. This time period also coincides with a switch in the Pacific CaCO 3 dissolution cyclicity [ Sexton and Barker , ] and in the δ 13 C‐δ 18 O correlation pattern in carbonates [ Turner , ]. These data collectively suggest a fundamental change in the interplay between productivity and climate, associated with the intensification of the glaciation at the MPT.…”

Section: Discussionsupporting

confidence: 66%

“…The observed shift in the timing of maximum export production relative to climate parameters (e.g., δ 18 O, ice volume, SST, and dust deposition) at ~1.1 Ma which is also captured in other records in this region, including opal accumulation and diatom biomarkers [ Hayes et al , ], C isotopes [ Lisiecki , ; Turner , ], and N isotopes [ Robinson et al , ] indicates a change in this coupling. In relation to drivers, it is interesting to note that records of dust deposition as seen in ice cores [ Fuhrer et al , ; Petit et al , ] and in sedimentary records in this region [ Anderson et al , ; Calvo et al , ; McGee et al , ; Winckler et al , ] are highest during maximum glaciations while the maximum productivity is offset from glacial maxima (mostly during deglaciation), suggesting that dust deposition did not contribute to increased productivity in the EEP since 1.1 Ma.…”

Section: Discussionmentioning

confidence: 68%

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Export production fluctuations in the eastern equatorial Pacific during the Pliocene‐Pleistocene: Reconstruction using barite accumulation rates

Ravelo

Liu

et al. 2015

Paleoceanography

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Export production is an important component of the carbon cycle, modulating the climate system by transferring CO2 from the atmosphere to the deep ocean via the biological pump. Here we use barite accumulation rates to reconstruct export production in the eastern equatorial Pacific over the past 4.3 Ma. We find that export production fluctuated considerably on multiple time scales. Export production was on average higher (51 g C m−2 yr−1) during the Pliocene than the Pleistocene (40 g C m−2 yr−1), decreasing between 3 and 1 Ma (from more than 60 to 20 g C m−2 yr−1) followed by an increase over the last million years. These trends likely reflect basin‐scale changes in nutrient inventory and ocean circulation. Our record reveals decoupling between export production and temperatures on these long (million years) time scale. On orbital time scales, export production was generally higher during cold periods (glacial maxima) between 4.3 and 1.1 Ma. This could be due to stronger wind stress and higher upwelling rates during glacial periods. A shift in the timing of maximum export production to deglaciations is seen in the last ~1.1 million years. Results from this study suggest that, in the eastern equatorial Pacific, mechanisms that affect nutrient supply and/or ecosystem structure and in turn carbon export on orbital time scales differ from those operating on longer time scales and that processes linking export production and climate‐modulated oceanic conditions changed about 1.1 million years ago. These observations should be accounted for in climate models to ensure better predictions of future climate change.

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Section: Discussionsupporting

confidence: 66%

Section: Discussionmentioning

confidence: 68%

Export production fluctuations in the eastern equatorial Pacific during the Pliocene‐Pleistocene: Reconstruction using barite accumulation rates

Ravelo

Liu

et al. 2015

Paleoceanography

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“…The glacial-interglacial cycles of the late Pleistocene appear to be eccentricitypaced, whilst ∼100 and ∼400 kyr cycles are also prominently present in mid-and early Cenozoic and Mesozoic geological records (e.g. Herbert & Fischer 1986;Lourens et al 2005;Kirtland Turner 2014). The discrepancy between the small changes in annual mean insolation and the relatively large climate consequences that result could imply that processes intrinsic to Earth may lead to a highly nonlinear response between insolation and climate (Hays et al 1976;Clemens & Tiedemann 1997).…”

Section: Milankovitch Cycles Of the Earthmentioning

confidence: 99%

Quantifying the Influence of Jupiter on the Earth’s Orbital Cycles

Horner

Vervoort

Kane

et al. 2019

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A wealth of Earth-sized exoplanets will be discovered in the coming years, proving a large pool of candidates from which the targets for the search for life beyond the Solar system will be chosen. The target selection process will require the leveraging of all available information in order to maximize the robustness of the target list and make the most productive use of follow-up resources. Here, we present the results of a suite of n-body simulations that demonstrate the degree to which the orbital architecture of the Solar system impacts the variability of Earth's orbital elements. By varying the orbit of Jupiter and keeping the initial orbits of the other planets constant, we demonstrate how subtle changes in Solar system architecture could alter the Earth's orbital evolution -a key factor in the Milankovitch cycles that alter the amount and distribution of solar insolation, thereby driving periodic climate change on our planet. The amplitudes and frequencies of Earth's modern orbital cycles fall in the middle of the range seen in our runs for all parameters considered -neither unusually fast nor slow, nor large nor small. This finding runs counter to the 'Rare Earth' hypothesis, which suggests that conditions on Earth are so unusual that life elsewhere is essentially impossible. Our results highlight how dynamical simulations of newly discovered exoplanetary systems could be used as an additional means to assess the potential targets of biosignature searches, and thereby help focus the search for life to the most promising targets.

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“…Analogies between P/E and modern climate phenomena such as the monsoon system are limited because of different continental configuration, baseline climate, etc. Moreover, the global climate and carbon cycle response during, e.g., the late Pleistocene (as expressed in 13 C and 18 O records) fundamentally differs from that of the early Paleogene, for one due to the presence/absence of large ice sheets [e.g., Wang et al, 2010;Russon et al, 2010;Kirtland Turner, 2014]. Nevertheless, late Pleistocene monsoon records indicate a direct relationship between the eccentricity-modulated precession/insolation amplitude and Asian monsoon variation on precessional time scale.…”

Section: A Forcing Mechanismmentioning

confidence: 99%

Orbital forcing of the Paleocene and Eocene carbon cycle

et al. 2017

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Multimillion‐year proxy records across the Paleocene and Eocene show prominent variations on orbital time scales. The cycles, which have been identified at various sites across the globe, preferentially concentrate spectral power at eccentricity and precessional frequencies. It is evident that these cycles are an expression of changes in global climate and carbon cycling paced by astronomical forcing. However, little is currently known about the link between orbital forcing and the carbon cycle‐climate system and the amplitude of associated atmospheric CO2 variations. Here we use simple and complex carbon cycle models to explore the basic effect of different orbital forcing schemes and noise on the carbon cycle. Our primary modeling target is the high‐resolution, ∼7.7 Myr long, benthic isotope record at Ocean Drilling Program Site 1262 in the South Atlantic. For direct insolation forcing (as opposed to artificial eccentricity‐tilt‐precession), one major challenge is understanding how the system transfers spectral power from high to low frequencies. We discuss feasible solutions, including insolation transformations analogous to electronic AC‐DC conversion (DC'ing). Regarding mechanisms, we focus on tropical insolation and a long‐term carbon imbalance in terrestrial organic burial/oxidation but do not rule out other scenarios. Our analysis shows that high‐latitude mechanisms are unlikely drivers of orbitally paced changes in the late Paleocene‐early Eocene (LPEE) Earth system. Furthermore, we provide constraints on the origin and isotopic composition of a possible LPEE cyclic carbon imbalance/source responding to astronomical forcing. Our simulations also reveal a mechanism for the large δ13C‐eccentricity lag at the 400 kyr period observed in Paleocene, Oligocene, and Miocene sections. We present the first estimates of orbital‐scale variations in atmospheric CO2 during the late Paleocene and early Eocene.

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Pliocene switch in orbital‐scale carbon cycle/climate dynamics

Cited by 34 publications

References 71 publications

Export production fluctuations in the eastern equatorial Pacific during the Pliocene‐Pleistocene: Reconstruction using barite accumulation rates

Export production fluctuations in the eastern equatorial Pacific during the Pliocene‐Pleistocene: Reconstruction using barite accumulation rates

Quantifying the Influence of Jupiter on the Earth’s Orbital Cycles

Orbital forcing of the Paleocene and Eocene carbon cycle

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