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

Abstract

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.

Defining paleoclimatic routes and opportunities for hominin dispersals across Iran

“…Speleothem records provide detailed insights into terrestrial paleoenvironmental conditions in northern Iran during periods with a positive moisture balance. The Qaleh Kurd cave (with a record covering 127–73 ka and 7.5–6.5 ka) in NW Iran ( Fig 3 Site 5), and Pir Ghar cave (with a stalagmite record spanning 100–70 ka) in the NE of the country ( Fig 3 Site 11), provide key information, especially for MIS 5 [ 44 , 78 ]. Both reconstructions indicate multiple wet phases during MIS 5 ( Fig 5 ), comparable to the Lake Urmia profile and the loess records.…”

“…C) Pollen record from Lake Urmia, Zeribar and Mirabad lakes from along the northern to central Zagros, showing arboreal to non-arboreal pollen ratio, suggestive of forest/shrubs vegetation during MIS 5 and 1 [ 63 , 67 , 93 ]. D) Speleothem studies from Qaleh Kurd in western and Pir Ghar in the eastern Iranian Plateau, showing wetter conditions during phases of MIS 5 and also the Holocene [ 44 , 78 ]. E) Alluvial fan and river terrace abandonment [ 80 , 81 ].…”

Termination 1 Millennial‐Scale Rainfall Events Over the Sunda Shelf

“…Carolin et al (2013Carolin et al ( , 2016 reported U-Th ages measured in the lower portion of stalagmite SC02, 105-31 ka (thousand years before 1950 C.E.). In the upper portion, four of the 18 U-Th samples were analyzed in the Division of Geological and Planetary Sciences at the California Institute of Technology, and 14 samples were analyzed in the Department of Earth Sciences at the University of Oxford, following the methods of Carolin et al (2016Carolin et al ( , 2019. A detailed description of the U-Th age sampling, multicollector inductively coupledplasma mass spectrometer (MC-ICP-MS) measurements, and sample age error analysis is found in Text S2 in the Supporting Information S1.…”

Modelling Neanderthals’ dispersal routes from Caucasus towards east

“…Our main data on the paleoclimate of the Iranian Plateau during MIS 5 comes from speleothem growth and δ18O records of Qale Kord [ 74 ] and Pir Ghar [ 75 ] caves located in the northeast edge of the Zagros Mountains and in the east of the Iranian Plateau, respectively. Further information is provided by the palynological study of a sediment core from Lake Urmia [ 76 ].…”