Early-Holocene greening of the Afro-Asian dust belt changed sources of mineral dust in West Asia

Sharifi, Arash; Murphy, Lisa N.; Pourmand, A.; Clement, A. C.; Canuel, Elizabeth A.; Beni, Abdolmajid Naderi; Lahijani, Hamid; Delanghe, Doriane; Ahmady‐Birgani, Hesam

doi:10.1016/j.epsl.2017.10.001

Cited by 34 publications

(43 citation statements)

References 60 publications

(94 reference statements)

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“…Their modeling indicates a southward shift of the MLWJ during the second part of the Holocene, with related changes in cyclogenesis over Mediterranean. The importance in the shift of the position of the MLWJ is also documented in dust proxy records from the Middle East and east Asia (e.g., Nagashima al., 2011;Sharifi et al, 2015Sharifi et al, , 2018. According to Sharifi et al (2018), evidence from the dust record from the Neor peat mire in Iran and climate modeling shows that at approximately 4.2 ka there is a migration of the main axis of the MLWJ towards the Equator allowing the transport of higher fluxes of dust from west Asia as well as from the northeast Africa.…”

Section: Is a Synthesis Possible?mentioning

confidence: 99%

The 4.2 ka BP Event in the Mediterranean region: an overview

et al. 2019

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The Mediterranean region and the Levant have returned some of the clearest evidence of a climatically dry period occurring around 4200 years ago. However, some regional evidence is controversial and contradictory, and issues remain regarding timing, progression, and regional articulation of this event. In this paper, we review the evidence from selected proxies (sea-surface temperature, precipitation, and temperature reconstructed from pollen, δ 18 O on speleothems, and δ 18 O on lacustrine carbonate) over the Mediterranean Basin to infer possible regional climate patterns during the interval between 4.3 and 3.8 ka. The values and limitations of these proxies are discussed, and their potential for furnishing information on seasonality is also ex-plored. Despite the chronological uncertainties, which are the main limitations for disentangling details of the climatic conditions, the data suggest that winter over the Mediterranean involved drier conditions, in addition to already dry summers. However, some exceptions to this prevail -where wetter conditions seem to have persisted -suggesting regional heterogeneity in climate patterns. Temperature data, even if sparse, also suggest a cooling anomaly, even if this is not uniform. The most common paradigm to interpret the precipitation regime in the Mediterranean -a North Atlantic Oscillation-like pattern -is not completely satisfactory to interpret the selected data.

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Section: Is a Synthesis Possible?mentioning

confidence: 99%

The 4.2 ka BP Event in the Mediterranean region: an overview

et al. 2019

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“…A glaciogeomorphological survey to attest the evidence of glacier extension in the Arjan area would be helpful to investigate this. We therefore propose that a combination of lower evaporation due to lower annual temperatures, still significant precipitation due to the occasional penetration of southward-pushed westerlies into the southern Zagros (see Sharifi et al 2018), and continuous glacier melting in the vicinity of the wetland could explain the high lake levels of Arjan during the YD.…”

Section: Palaeoclimatic Implicationsmentioning

confidence: 95%

“…(1) The intensity of the Siberian High during the YD was higher compared to the early Holocene (Mayewski et al 1997;Sharifi et al 2015). This would have pushed the westerlies to the south providing precipitation over the central and southern Zagros (Sharifi et al 2018). However, YD pollen assemblages in Arjan are dominated by Amaranthaceae (Chenopodiaceae) with very low relative abundances of Poaceae (Fig.…”

Section: Palaeoclimatic Implicationsmentioning

confidence: 99%

A major hydrobiological change in Dasht-e Arjan Wetland (southwestern Iran) during the late glacial – early Holocene transition revealed by subfossil chironomids

et al. 2019

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The late glacial -early Holocene transition is a key period in the earth's history. However, although this transition is well studied in Europe, it is not well constrained in the Middle East and palaeohydrological records with robust chronologies remain scarce from this region. Here we present an interesting hydrobiological record showing a major environmental change occurring in the Dasht-e Arjan Wetland (southwestern Iran, near to Persepolis) during the late glacial -early Holocene transition (ca. 11 650 years cal BP). We use subfossil chironomids (Insecta: Diptera) as a proxy for hydrological changes and to reconstruct lake-level fluctuations. The Arjan wetland was a deep lake during the Younger Dryas marked by a dominance of Chironomus plumosus/anthracinus-type, taxa adapted to anoxic conditions of deep waters. At the beginning of the Holocene, a drastic decrease (more than 80% to less than 10%) of Chironomus plumosus/anthracinus-type, combined with diversification of littoral taxa such as Polypedilum nubeculosum-type, Dicrotendipes nervosus-type, and Glyptotendipes pallens-type, suggests a lake-level decrease and a more vegetalized aquatic environment. We compare and contrast the chironomid record of Arjan with a similar record from northwestern Iran. The palaeoclimatic significance of the record, at a local and regional scale, is subsequently discussed. The increase in Northern Hemisphere temperatures, inferred by geochemical data from NGRIP, at the beginning of the Holocene best explains the change from the Younger Dryas highstand to early Holocene lowstand conditions in the Dasht-e Arjan wetland. However, a contribution of the meltwater inflow from small local glaciers in the catchment basin is not excluded.Résumé : La transition tardiglaciaire -Holocène précoce représente une période clé de l'histoire de la terre. Si cette transition est bien étudiée en Europe, ce n'est toutefois pas le cas au Moyen-Orient, et les profils paléohydrologiques associés à des chronologies robustes demeurent rares pour cette région. Nous présentons un profil hydrobiologique intéressant qui montre un important changement environnemental s'étant produit dans la zone humide de Dasht-e Arjan (sud-ouest de l'Iran, près de Persépolis) durant la transition tardiglaciaire-Holocène précoce (vers 11 650 ans cal BP). Nous utilisons des subfossiles de chironomidés (insectes : diptères) comme indicateurs de changements hydrologiques et pour reconstituer les fluctuations du niveau de lacs. Le milieu humide d'Arjan était un lac profond durant le Dryas récent, caractérisé par une prépondérance de taxons de type Chironomus plumosus/anthracinus adaptés aux conditions anoxiques des eaux profondes. Une baisse drastique (de plus de 80 % à moins de 10 %) de ces taxons au début de l'Holocène, combinée à la diversification de taxons littoraux de types Polypedilum nubeculosum, Dicrotendipes nervosus et Glyptotendipes pallens, indiquerait une baisse du niveau du lac et un milieu aquatique plus végétalisé. Nous comparons le profil des chironomidés d'Ar...

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“…Interest in investigating past climate change in this region stems from the desire to better constrain our knowledge of the system's precipitation variability and its response to various external forcings (Aubert et al, 2017;Carolin et al, 2019;Flohr et al, 2017;Mehterian et al, 2017;Sharifi et al, 2015;Sharifi et al, 2018). Interest in investigating past climate change in this region stems from the desire to better constrain our knowledge of the system's precipitation variability and its response to various external forcings (Aubert et al, 2017;Carolin et al, 2019;Flohr et al, 2017;Mehterian et al, 2017;Sharifi et al, 2015;Sharifi et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

“…Society and ecosystems in the center of the Middle East region (Syria, Iraq, and Iran) are highly vulnerable to changes in water availability, with annual precipitation generally low, around 100-200 mm/year, outside of the higher elevation mountainous areas (European Centre for Medium-range Weather Forecast (ECMWF), 2011). Interest in investigating past climate change in this region stems from the desire to better constrain our knowledge of the system's precipitation variability and its response to various external forcings (Aubert et al, 2017;Carolin et al, 2019;Flohr et al, 2017;Mehterian et al, 2017;Sharifi et al, 2015;Sharifi et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Drying in the Middle East During Northern Hemisphere Cold Events of the Early Glacial Period

Carolin

Ersek

Roberts

et al. 2019

Geophysical Research Letters

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Few paleoclimate records exist to assess the central Middle East's response to natural forcing beyond the instrumental record. Here, we present a multiproxy stalagmite-based climate reconstruction from Iran's semiarid northeast that spans 100-70,000 years before present. During severe cold (stadial) events in the North Atlantic at ≈88, 77, and 73 ka, stalagmite trace-element data indicate anomalously dry periods at this location. Stadial event increases in the stalagmite oxygen isotopes mirror those in a published Iranian stalagmite 800 km to the west. A global climate model simulates drying across the Middle East region in response to stadial event forcing, in agreement with oxygen isotope enrichments in both Iranian records, caused by a smaller fractional loss of moisture on the trajectory upstream. The paleoproxies and model experiments are consistent in indicating a drier Middle East climate during the cold North Atlantic stadials.Plain Language Summary Iran is particularly vulnerable to the effects of climate change due to its scarce water availability. Iran's climate likely changed in the past due to natural causes, indications of which can be found in climate archives such as tens-of-thousands-of-year-old cave stalagmites. Stalagmites record evidence of changes in rainfall pattern and amount. This study presents a reconstruction of both regional and local rainfall changes based on the geochemistry of stalagmites from northwest and northeast Iran. The record covers 100-70,000 years before present, a period when ice sheets covered North America and northern Europe, and Earth was experiencing multiple abrupt shifts to even colder conditions in the Northern Hemisphere. Each event's shift to colder temperatures lasted for a few thousand years. We show that both the stalagmite geochemical data and state-of-the-climate models are consistent in indicating a drier Middle East climate during these cold events.

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Early-Holocene greening of the Afro-Asian dust belt changed sources of mineral dust in West Asia

Cited by 34 publications

References 60 publications

The 4.2 ka BP Event in the Mediterranean region: an overview

The 4.2 ka BP Event in the Mediterranean region: an overview

A major hydrobiological change in Dasht-e Arjan Wetland (southwestern Iran) during the late glacial – early Holocene transition revealed by subfossil chironomids

Drying in the Middle East During Northern Hemisphere Cold Events of the Early Glacial Period

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