Pluvial periods in Southern Arabia over the last 1.1 million-years

Abstract

Past climates and environments experienced by the Saharo-Arabian desert belt are of prime importance for palaeoclimatic and palaeoanthropological research. On orbital timescales transformations of the desert into a savannah-like landscape in response to higher precipitation provided "windows of opportunity" for hominin dispersal from Africa into Eurasia. On long timescales, palaeoenvironmental reconstructions for the region are predominantly derived from marine sediments and available terrestrial records from the Arabian Peninsula are limited to 450 ka before present (BP). Here, we present a new stalagmite-based palaeoclimate record from Mukalla Cave in Yemen which extends back to ~1.1 million years BP or Marine Isotope Stage (MIS) 31, as determined by Uranium-lead dating. Stalagmite Y99 grew only during peak interglacial periods and warm substages back to ~1.1 Ma. Stalagmite calcite oxygen isotope (δ 18 O) values show that every past interglacial humid period was wetter than the Holocene, a period in which large lakes formed in the now arid areas of southern Arabia. Carbon isotope (δ 13 C) values indicate habitable savannah-like environments developed during these pluvial periods. A total of 21 pluvial periods with precipitation of more than 300 mm yr -1 occurred since ~1.1 Ma and thus numerous opportunities for hominin dispersals occurred throughout the Pleistocene. New determinations of hydrogen (δDFI) and oxygen (δ 18 OFI) isotopes in stalagmite fluid inclusion water demonstrates that enhanced precipitation in Southern Arabia was brought by the African and Indian Summer Monsoons. When combined with subannual calcite analysis of δ 18 O and δ 13 C, these data reveal a distinct wet (summer) and dry (winter) seasonality. Highlights • Pluvial periods recorded in stalagmites from Southern Arabia up to 1.073 Ma (MIS 31) • Speleothem growth in Yemen only occurred during interglacial maxima and warm substages • The African Summer Monsoon (ASM) and Indian Summer Monsoon (ISM) increased precipitation to Southwestern Arabia • Monsoonal rainfall increased precipitation to south-eastern Arabia • All Pleistocene pluvial periods were wetter than the Holocene pluvial period • Grassland environments formed during peak interglacials • Interglacial grasslands provided "windows of opportunity" for hominin occupation of the now arid Arabian interior and dispersals from Africa.

Multiple hominin dispersals into Southwest Asia over the past 400,000 years

“…a detailed record for the woodlands, a southern extension of the Palaearctic biome 4,16 . However, in the past decade, research in the Arabian Peninsula has begun to document hominin occupations of the arid Saharo-Arabian biome during episodically wetter periods characterized by grasslands, lakes and rivers 5,10,[17][18][19][20][21][22][23][24][25][26][27][28][29] . Emerging patterns of spatially divergent cultural-evolutionary developments in Southwest Asia include a young (less than 200 thousand years ago (ka)) Acheulean in central Arabia 24 , a technology typically associated with earlier hominins such as Homo erectus.…”

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U–Pb carbonate geochronology: strategies, progress, and limitations

“…Similarly, uncertainty propagation and data reporting should follow the community-based guidelines for zircon of Horstwood et al (2016). Details on the LA-ICP-MS method for carbonate adopted by three major laboratories taking a similar approach are provided in Roberts and Walker (2016) and Drake et al (2017) for the British Geological Survey laboratory (Nottingham, UK); Ring and Gerdes (2016) and Methner et al (2016) for Goethe Universität (Frankfurt, Germany); and Nuriel et al (2017Nuriel et al ( , 2019 for the University of California Santa Barbara (Santa Barbara, USA). Ablation spot sizes are typically larger than for silicate or phosphate minerals -generally > 40 µm and often > 100 µm -and fluences are also often high (> 4 J cm −2 ).…”

“…To date, LA-ICP-MS U-Pb carbonate geochronology has been utilised for a wide range of applications. These include the dating of speleothem deposition (Hopley et al, 2019;Scardia et al, 2019;Nicholson et al, 2020), brittle deformation (Roberts and Walker, 2016;Ring and Gerdes, 2016;Goodfellow et al, 2017;Hansman et al, 2018;Parrish et al, 2018;Beaudoin et al, 2018;Nuriel et al, 2017Nuriel et al, , 2019; Smeraglia et al, 2019), hydrocarbon migration (Holdsworth et al, , 2020, hydrothermal ore mineralisation (Burisch et al, 2017(Burisch et al, , 2019Kreissl et al, 2018), hydrothermal and deep-crustal fluid flow (Drake et al, 2017(Drake et al, , 2019(Drake et al, , 2020Mazurek et al, 2018;Walter et al, 2018;Incerpi et al, 2020;MacDonald et al, 2019), pedogenesis (Methner et al, 2016;Liivamägi et al, 2019), ocean crust alteration (Coogan et al, 2016), diagenesis in sedimentary deposits (Li et al, 2014;Pagel et al, 2018;Mangenot et al, 2018;Godeau et al, 2018;Lawson et al, 2018), and sedimentary deposition (Drost et al, 2018). Published dates range in age from 0.6 to 548 Ma (see Fig.…”

“…Smith and Farquhar, 1989;DeWolf and Halliday, 1991;Brannon et al, 1996;Rasbury et al, 1997;Richards et al, 1998;Woodhead et al, 2006;Pickering et al, 2010), collectively referred to here simply as ID. More recently, there has been a proliferation in the use of laser ablation (LA-) ICP-MS applied to calcite geochronology (Li et al, 2014;Coogan et al, 2016;Roberts and Walker, 2016;Ring and Gerdes, 2016;Methner et al, 2016;Goodfellow et al, 2017;Burisch et al, 2017Burisch et al, , 2018Drake et al, 2017Drake et al, , 2019Drake et al, , 2020Hansman et al, 2018;Hellwig et al, 2018;Godeau et al, 2018;Beaudoin et al, 2018;Bertok et al, 2019;Drost et al, 2018;Mangenot et al, 2018;Nicholson et al, 2020;Nuriel et al, 2017Nuriel et al, , 2019Parrish et al, 2018;Walter et al, 2018;Yokoyama et al, 2018;Smeraglia et al, 2019;MacDonald et al, 2019;Scardia et al, 2019). Presently, we are not aware of successful secondary ion mass spectrometry (SIMS) U-Pb dating of carbonate mineralisation, but this presents an alternative microbeam method to laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS).…”

Stable Isotope Composition of Cyclone Mekunu Rainfall, Southern Oman

“…Importantly, this method also works in hindsight, that is, one can evaluate the groundwater's isotopic composition as an integral signal. Hence, the technique is not only applicable to modern water, but also to old groundwater and other paleoclimatic archives preserving the isotopic signature, such as speleothem calcite ( δ 18 O calcite ) or fluid inclusions ( δ 18 O, δ 2 H; Fleitmann & Matter, 2009, Nicholson et al, 2020).…”