Middle Miocene climate cooling linked to intensification of eastern equatorial Pacific upwelling

Holbourn, Ann; Kuhnt, Wolfgang; Lyle, M.; Schneider, Leah; Romero, Oscar E; Andersen, Nils

doi:10.1130/g34890.1

Cited by 198 publications

(276 citation statements)

References 19 publications

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“…In more detail, pulses A and B coincide with two major cooling steps within the Miocene Climate Transition, which marks progressive change from eccentricity-paced glacial-interglacial cycles to obliquity-paced cycles (11). During these cooling steps, bottom water temperatures decreased by around 3°C and seasurface temperatures decreased by up to about 7°C (10).…”

Section: Resultsmentioning

confidence: 93%

“…Highly variable ice sheets that characterized the mid-Miocene Climate Optimum (8,9) subsequently expanded during the cooling associated with the Miocene Climate Transition ∼14 Ma (10,11), at which time a large terrestrial ice sheet became a relatively permanent feature on the East Antarctic continent. Marine-based ice, grounded on bedrock below sea level in West and East Antarctica, continued to expand and contract through variable climates of the late Miocene and into the Pliocene (14-3 Ma) (12, 13), driving global sea-level fluctuations of between 20-to 30-m amplitude and up to 20 m above the present-day level (14).…”

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confidence: 99%

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Southern Ocean phytoplankton turnover in response to stepwise Antarctic cooling over the past 15 million years

Crampton

Cody

Levy

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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It is not clear how Southern Ocean phytoplankton communities, which form the base of the marine food web and are a crucial element of the carbon cycle, respond to major environmental disturbance. Here, we use a new model ensemble reconstruction of diatom speciation and extinction rates to examine phytoplankton response to climate change in the southern high latitudes over the past 15 My. We identify five major episodes of species turnover (origination rate plus extinction rate) that were coincident with times of cooling in southern high-latitude climate, Antarctic ice sheet growth across the continental shelves, and associated seasonal sea-ice expansion across the Southern Ocean. We infer that past plankton turnover occurred when a warmer-than-present climate was terminated by a major period of glaciation that resulted in loss of open-ocean habitat south of the polar front, driving non-ice adapted diatoms to regional or global extinction. These findings suggest, therefore, that Southern Ocean phytoplankton communities tolerate "baseline" variability on glacial-interglacial timescales but are sensitive to large-scale changes in mean climate state driven by a combination of long-period variations in orbital forcing and atmospheric carbon dioxide perturbations.

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Section: Resultsmentioning

confidence: 93%

mentioning

confidence: 99%

Southern Ocean phytoplankton turnover in response to stepwise Antarctic cooling over the past 15 million years

Crampton

Cody

Levy

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…The shift between Zones 1 and Zone 2 could reflect the cooling event Mi-2, although this event is dated around 16.0 Ma [58]. Alternatively, a ''peak warmth'' centred around 15.6 Ma has been described from the Pacific Ocean and Antarctica [2,6,8]. It is therefore possible that the boundary between Zones 1 and 2 is related to the end of the ''peak warmth''.…”

Section: Possible Mechanisms For Palaeoenvironmental Changementioning

confidence: 99%

“…Until now, the MMCO has been mainly investigated using marine isotopic data [1,2,5,6], since terrestrial outcrops are relatively scarce. In Antarctica, a palynological study and leaf wax geochemistry revealed a warmer and wetter climate than today, and demonstrated that Antarctica could support a tundra vegetation [7,8].…”

Section: Introductionmentioning

confidence: 99%

Lake geochemistry reveals marked environmental change in Southwest China during the Mid Miocene Climatic Optimum

Lebreton-Anberrée

et al. 2016

Science Bulletin

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The Mid-Miocene Climatic Optimum (MMCO; *15-17 Ma) was one of the short-term climatic warm events that punctuated the Cenozoic long-term cooling trend. Because there are very few terrestrial records of this event, most of our understanding comes from marine cores. In this report, we first present new palaeomagnetic data that revises the dating of our 400 m-thick lacustrine section in Wenshan (Yunnan), previously thought to be Late Miocene. These new data suggest an older age, ca. 15.2-16.5 Ma, coinciding with the MMCO. We measured d 13 C on bulk organic matter (d 13 C org ), total organic carbon (TOC), total nitrogen (TN) and C/N ratios at a high sample resolution to: (1) reconstruct the palaeoenvironmental changes in the lake catchment area, and (2) infer mechanisms responsible for these changes. Our results show that all four geochemical parameters demonstrate that a strong environmental change occurred around the middle of the section, shortly after the C5Cn/C5Br geomagnetic reversal and the Early/Middle Miocene boundary at 15.97 Ma. We propose that the environmental shift may be due to a combination of a change in climate, which became cooler, together with a change in organic matter cycling within the lake. This study provides a new insight into the MMCO and demonstrates that although the MMCO was generally a warm event, it was also a time of climatic instability and abrupt environmental changes.Keywords Yunnan Á Mid-Miocene Climatic Optimum Á Bulk organic carbon isotopes (d 13 C org ) Á C/N ratio Á TOC Electronic supplementary material The online version of this article

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“…• Understand the timing and conditions under which monsoonal circulation initiated and reconstruct the variability of the Indian monsoon at orbital timescales; • Understand the relationship between Indian monsoon variability and major past global climatic events such as the Oligocene/Miocene cooling (Zachos et al, 1997), the onset of the mid-Miocene climatic optimum (Holbourn et al, 2007(Holbourn et al, , 2014Zachos et al, 2001), mid-Miocene cooling and Antarctic cryosphere expansion (Holbourn et al, 2013), and the PliocenePleistocene enhancement of Northern Hemisphere glaciation Raymo, 2005, 2007); • Establish a complete Oligocene-present astronomically tuned timescale based on high-resolution benthic and planktonic isotope reference curves for the Indian Ocean; and • Integrate high-resolution distribution studies of well-preserved Oligocene-recent calcareous and siliceous microfossils from the Indian Ocean into global compilation studies of paleoclimatic and biotic evolution.…”

Section: Campanian-miocene Objectivesmentioning

confidence: 99%

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Clemens¹,

Kuhnt²,

LeVay³

et al. 2015

International Ocean Discovery Program Preliminary Report

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Middle Miocene climate cooling linked to intensification of eastern equatorial Pacific upwelling

Cited by 198 publications

References 19 publications

Southern Ocean phytoplankton turnover in response to stepwise Antarctic cooling over the past 15 million years

Southern Ocean phytoplankton turnover in response to stepwise Antarctic cooling over the past 15 million years

Lake geochemistry reveals marked environmental change in Southwest China during the Mid Miocene Climatic Optimum

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