First evidence for human occupation of a lava tube in Arabia: The archaeology of Umm Jirsan Cave and its surroundings, northern Saudi Arabia

Recent advances in interdisciplinary archaeological research in Arabia have focused on the evolution and historical development of regional human populations as well as the diverse patterns of cultural change, migration, and adaptations to environmental fluctuations. Obtaining a comprehensive understanding of cultural developments such as the emergence and lifeways of Neolithic groups has been hindered by the limited preservation of stratified archaeological assemblages and organic remains, a common challenge in arid environments. Underground settings like caves and lava tubes, which are prevalent in Arabia but which have seen limited scientific exploration, offer promising opportunities for addressing these issues. Here, we report on an archaeological excavation and a related survey at and around Umm Jirsan lava tube in the Harrat Khaybar, north-western Saudi Arabia. Our results reveal repeated phases of human occupation of the site ranging from at least the Neolithic through to the Chalcolithic/Bronze Age. Pastoralist use of the lava tube and surrounding landscape is attested in rock art and faunal records, suggesting that Umm Jirsan was situated along a pastoral route linking key oases. Isotopic data indicates that herbivores primarily grazed on wild grasses and shrubs rather than being provided with fodder, while humans had a diet consistently high in protein but with increasing consumption of C3 plants through-time, perhaps related to the emergence of oasis agriculture. While underground and naturally sheltered localities are globally prominent in archaeology and Quaternary science, our work represents the first such combined records for Saudi Arabia and highlight the potential for interdisciplinary studies in caves and lava tubes

Before the Holocene humid period: Life-sized camel engravings and early occupations on the southern edge of the Nefud desert

The Neolithic of northern Arabia is characterised by monumental stone structures, ephemeral ‘hearth sites’ indicative of a highly mobile lifestyle, and a rich rock art heritage with iconic representations of domesticated livestock. However, the character and timing of occupation prior to the spread of pastoralism (ca. 6000 BCE) remains elusive, with only one stratified Epipalaeolithic site and two surface early Neolithic sites so-far known in the Jubbah Oasis. Here we present Sahout, a newly documented rock art site with Neolithic and earlier occupations, on the southern edge of the Nefud desert. The rock art is dominated by life-sized, naturalistic, engravings of camels, which are in some cases superimposed with Neolithic imagery of domesticated sheep. Surveys and test excavations carried out in the vicinity of the rock art revealed a lithic assemblage with similarities to the late Epipalaeolithic and Pre-Pottery Neolithic of the Levant. Radiocarbon ages from two test trenches and two hearths indicate repeated occupation at Sahout between the Terminal Pleistocene and the Middle Holocene, which partly mirror the rock art sequence. Investigations at Sahout indicate that rock art production in northern Arabia may have begun earlier than previously thought. Research also suggests a broader geographical extent to human occupations prior to the Holocene humid period

Before the Holocene humid period: Life-sized camel engravings and early occupations on the southern edge of the Nefud desert

The Neolithic of northern Arabia is characterised by monumental stone structures, ephemeral ‘hearth sites’ indicative of a highly mobile lifestyle, and a rich rock art heritage with iconic representations of domesticated livestock. However, the character and timing of occupation prior to the spread of pastoralism (ca. 6000 BCE) remains elusive, with only one stratified Epipalaeolithic site and two surface early Neolithic sites so-far known in the Jubbah Oasis. Here we present Sahout, a newly documented rock art site with Neolithic and earlier occupations, on the southern edge of the Nefud desert. The rock art is dominated by life-sized, naturalistic, engravings of camels, which are in some cases superimposed with Neolithic imagery of domesticated sheep. Surveys and test excavations carried out in the vicinity of the rock art revealed a lithic assemblage with similarities to the late Epipalaeolithic and Pre-Pottery Neolithic of the Levant. Radiocarbon ages from two test trenches and two hearths indicate repeated occupation at Sahout between the Terminal Pleistocene and the Middle Holocene, which partly mirror the rock art sequence. Investigations at Sahout indicate that rock art production in northern Arabia may have begun earlier than previously thought. Research also suggests a broader geographical extent to human occupations prior to the Holocene humid period

OSL dating results (see supplementary material for more details).

OSL dating results (see supplementary material for more details).</p

Rock art recorded at Umm Jirsan.

Top left: Panel 8, showing a mixed herd of sheep and goats as well as an ibex and several human figures. Bottom left: Photo of Panel 8 modified using the ybk setting on DStretch. Two engravings of dogs are shown in the inset and indicated with a circle on the panel. Both dogs are extremely simplified but show the characteristic curled up tail. Top right: close up of Panel 9, highlighting the difference in rock varnish, likely caused by water running down the rock face. Bottom right: close up of Panel 9 enhanced using the ybk setting on DStretch.</p

Species identifiable in the rock art of Umm Jirsan.

(A) sheep (Panel 8); (B) goat and two stick figures with tools on their belts (Panel 8); (C) long-horned cattle (Panel 6), photo enhanced using the ybk setting on DStretch; (D) ibex with ribbed horns and coat markings (Panel 4). Bottom: tracings of examples A-D.</p

Map of northern Arabia and key sites.

(A) Map showing the location of Umm Jirsan and key sites mentioned in the text, as well as the range of mustatils and desert kites [16, 17, 20, 24, 27, 39] and (B) pendant tombs (black lines and dots) in the Harrat Khaybar [31]. (C) Location of newly identified archaeological sites are shown in the inset: (A) stone structures (25.6087 N, 39.7502 E, 25.6020 N, 39.7289 E, and 25.5728 N, 39.7330 E); (B) ‘bow-tie’ shaped structure (25.6091 N, 39.7470 E); (C) lava tube collapse with rock art (25.5879 N, 39.7702 E); and (D) Umm Jirsan D area. Made with Copernicus COP-DEM 30 m and “Sentinel-2 cloudless—https://s2maps.edu by EOX IT Services GmBH (contains modified Copernicus Sentinel data 2020)”, under CC BY 4.0.</p

Photographs of the Umm Jirsan Cave and interior sections of the lava tube.

Top left, looking out of entrance to Umm Jirsan (Trench 1 just out of view on right). Top right, inside lava tube beyond Trench 1. Middle left, another example of a lava tube near Umm Jirsan. Middle right, Jebel Abyad area with obsidian clasts and lithics, beneath obsidian outcrops. Bottom, simple plan of the Umm Jirsan lava tube system with red star indicating the location of the Trench 1 excavation [modified from 40].</p

AMS radiocarbon ages from the excavation conducted in the hyena den as well as from elsewhere in Umm Jirsan.

Calibrated using Calib (v. 8.20) and IntCal20 [76]. Radiocarbon dating analysis conducted at the SUERC Radiocarbon Laboratory, University of Glasgow. Specimens with an asterisk (*) were obtained by Pint [36] and the remainder by Stewart et al. [40].</p

AMS radiocarbon ages from Umm Jirsan Trench 1 calibrated using Calib (v. 8.20) and using IntCal20 [76].

Radiocarbon dating analysis conducted at the SUERC Radiocarbon Laboratory, University of Glasgow.</p