Central Asian Drying at 3.3 Ma Linked to Tropical Forcing?

Su, Q.; Nie, Junsheng; Meng, Qingquan; Heermance, Richard V.; Gong, Lisha; Luo, Zhi; Wang, Zhao; Zhang, Rui; Garzione, Carmala N.

doi:10.1029/2019gl084648

Cited by 21 publications

(16 citation statements)

References 32 publications

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“…These out‐of‐the‐order grain size coarsening events within interglacials correspond well with insolation maxima paced by orbital eccentricity (arrows in Figures 6h and 6j), an observation that is supported by recent studies that infer an increased imprint of eccentricity, and in association precession, in the Qaidam Basin under high eccentricity amplitudes (Luo et al, 2018; Su et al, 2019; Su et al, 2019). During eccentricity maxima the amplitude of precession is larger, causing a summer season lengthening and thus potentially enhanced EASM precipitation (Berger, 1988; Braconnot et al, 2008).…”

Section: Resultssupporting

confidence: 83%

Sedimentological Evidence for Pronounced Glacial‐Interglacial Climate Fluctuations in NE Tibet in the Latest Pliocene to Early Pleistocene

Yin

Dewald

Kaboth‐Bahr

et al. 2020

Paleoceanog and Paleoclimatol

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The intensification of Northern Hemisphere glaciation (iNHG) and uplift of the Tibetan Plateau have been argued to be among the main drivers of climate change in midlatitude Central Asia during the Pliocene/Pleistocene. While most proxy records that support this hypothesis are from regions outside the Tibetan Plateau (such as from the Chinese Loess Plateau), detailed paleoclimatic information for the plateau itself during that time has yet remained elusive. Here we present a temporally highly resolved (~500 years) sedimentological record from the Qaidam Basin situated on the northeastern Tibetan Plateau that shows pronounced glacial-interglacial climate variability during the interval from 2.7 to 2.1 Ma. Glacial (interglacial) intervals are generally characterized by coarser (finer) grain size, minima (maxima) in organic matter content, and maxima (minima) in carbonate content. Comparison of our results with Earth's orbital parameters and proxy records from the Chinese Loess Plateau suggests that the observed climate fluctuations were mainly driven by changes in the Siberian High/East Asian winter monsoon system as a response to the iNHG. They are further proposed to be enhanced by the topography of the Tibetan Plateau and its impact on the position and intensity of the westerlies.Representing the largest continental plateau on Earth, the Tibetan Plateau has a substantial impact on the Earth's climate evolution during the Late

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Section: Resultssupporting

confidence: 83%

Sedimentological Evidence for Pronounced Glacial‐Interglacial Climate Fluctuations in NE Tibet in the Latest Pliocene to Early Pleistocene

Yin

Dewald

Kaboth‐Bahr

et al. 2020

Paleoceanog and Paleoclimatol

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“…Recently, magnetic parameters, including frequency‐dependent susceptibility (χ fd ) and χ fd /HIRM (χ fd to hard isothermal remanence magnetization ratio) have been demonstrated to faithfully track precipitation in the Loess Plateau and Qaidam Basin (Nie et al, 2017, 2020; Y. Song et al, 2014; Su et al, 2019). χ fd can detect the content of nm‐scale superparamagnetic (SP) ferrimagnetic grains of pedogenic origin and has been calibrated to precipitation using modern soils on the Chinese Loess Plateau (Maher & Thompson, 1995; Nie et al, 2010; Y.…”

Section: Discussionmentioning

confidence: 99%

“…Normalizing SP ferrimagnetic mineral content to hematite content therefore highlights the precipitation signal. χ fd /HIRM was initially calibrated using soils on the Chinese Loess Plateau (Z. F. Liu et al, 2013; Nie et al, 2017) but has shown great potential in fluvio‐lacustrine sediments without magnetic mineral dissolution (such as the Qaidam Basin strata) (Nie et al, 2017; Su et al, 2019). This is likely because the source regions have weathering crusts or soils recording past climate signals at that time, and transport of these materials to the depositional site enables χ fd /HIRM to record contemporary climate in the source regions.…”

Section: Discussionmentioning

confidence: 99%

“…However, this proxy can be complicated by provenance shifts (from carbonate depleted to carbonate enriched sources) and productivity changes (foraminifera production consuming Ca), which can potentially jeopardize the ability to reconstruct monsoon precipitation intensity. Recently, magnetic parameters, including frequency-dependent susceptibility (χ fd ) and χ fd / HIRM (χ fd to hard isothermal remanence magnetization ratio) have been demonstrated to faithfully track precipitation in the Loess Plateau and Qaidam Basin (Nie et al, 2017(Nie et al, , 2020Su et al, 2019). χ fd can detect the content of nm-scale superparamagnetic (SP) ferrimagnetic grains of pedogenic origin and has been calibrated to precipitation using modern soils on the Chinese Loess Plateau (Maher & Thompson, 1995;Nie et al, 2010;.…”

Section: Neogene East Asian Summer Monsoon Evolution and Mechanismsmentioning

confidence: 99%

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Temperature Control on Silicate Weathering Intensity and Evolution of the Neogene East Asian Summer Monsoon

Ren

Nie

Saylor

et al. 2020

Geophysical Research Letters

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Accurately reconstructing the evolution of the Asian monsoon is predicated on understanding the impact of temperature, precipitation, and tectonic paleogeography on silicate weathering proxies over million year timescales. We find that decreasing trends in chemical weathering proxies in both the northern and southern Tibetan Plateau match those from benthic oxygen isotope and sea surface temperature stacks since the late Miocene. In contrast, a synthesis of magnetic parameter‐based records and marine clastic flux records reveals stronger monsoon precipitation during both the warm middle Miocene and cool late Miocene, supporting model simulations showing that both paleogeography and atmospheric CO2 content are important in controlling the summer monsoon. This trend of increasing monsoon precipitation contrasts with the record of decreasing chemical weathering, suggesting that chemical weathering proxies are mainly regulated by temperature at million year timescales, rather than precipitation. These findings clarify reconstructions of the Cenozoic evolution of the East Asian summer monsoon.

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“…4m). Central Asian aridification has also been dated to 3.3 Ma, based on halite content, grain size, and magnetic proxies from the Qaidam Basin 52 . All of these developments would have impacted atmospheric dynamics and latitudinal temperature gradients that drive seasonal North African climate variability; we therefore retain H2 as a possibility.…”

Section: African Climate/environment Shift At 32 Mamentioning

confidence: 99%

Abrupt change in North African hydroclimate and landscape evolution 3.2 million years ago

Grant

Amarathunga

Amies

et al. 2021

Preprint

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Dark organic-rich layers (sapropels) have accumulated in Mediterranean sediments since the Miocene due to deep-sea dysoxia and enhanced carbon burial at times of intensified North African run-off during ‘Green’ Sahara Periods (GSPs). The existence of orbital precession-dominated Saharan aridity/humidity cycles is well known, but lack of long-term, high-resolution records hinders understanding of their precise relationships with environmental and hominin evolution. Here we present continuous, high-resolution geochemical and environmental magnetic records for the Eastern Mediterranean that span the past 5.2 million years, which reveal that organic burial in sapropels intensified 3.2 Myr ago. We deduce that fluvial terrigenous sediment inputs during GSPs doubled abruptly at this time, whereas monsoon run-off intensity remained relatively constant. We attribute the increase in sediment mobilisation to an abrupt non-linear North African landscape response associated with a major increase in arid:humid contrasts between GSPs and intervening dry periods. This likely limited hominin (and other animal) inhabitation of, and migration through, the Sahara region to GSPs only.

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Central Asian Drying at 3.3 Ma Linked to Tropical Forcing?

Cited by 21 publications

References 32 publications

Sedimentological Evidence for Pronounced Glacial‐Interglacial Climate Fluctuations in NE Tibet in the Latest Pliocene to Early Pleistocene

Sedimentological Evidence for Pronounced Glacial‐Interglacial Climate Fluctuations in NE Tibet in the Latest Pliocene to Early Pleistocene

Temperature Control on Silicate Weathering Intensity and Evolution of the Neogene East Asian Summer Monsoon

Abrupt change in North African hydroclimate and landscape evolution 3.2 million years ago

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