TY - JOUR

T1 - Microbial biomarkers reveal a hydrothermally active landscape at Olduvai Gorge at the dawn of the Acheulean, 1.7 Ma

AU - Sistiag, Ainara

AU - Husain, Fatima

AU - Uribelarrea, David

AU - Martin-Perea, David M.

AU - Ferland, Troy

AU - Freeman, Katherine H.

AU - Diez-Martin, Fernando

AU - Baquedano, Enrique

AU - Mabulla, Audax

AU - Dominguez-Rodrigo, Manuel

AU - Summons, Roger E.

PY - 2020

Y1 - 2020

N2 - Landscape-scale reconstructions of ancient environments within the cradle of humanity may reveal insights into the relationship between early hominins and the changing resources around them. Many studies of Olduvai Gorge during Pliocene-Pleistocene times have revealed the presence of precession-driven wet-dry cycles atop a general aridification trend, though may underestimate the impact of local-scale conditions on early hominins, who likely experienced a varied and more dynamic landscape. Fossil lipid biomarkers from ancient plants and microbes encode information about their surroundings via their molecular structures and composition, and thus can shed light on past environments. Here, we employ fossil lipid biomarkers to study the paleolandscape at Olduvai Gorge at the emergence of the Acheulean technology, 1.7 Ma, through the Lower Augitic Sandstones layer. In the context of the expansion of savanna grasslands, our results represent a resource-rich mosaic ecosystem populated by groundwater-fed rivers, aquatic plants, angiosperm shrublands, and edible plants. Evidence of a geothermally active landscape is reported via an unusual biomarker distribution consistent with the presence of hydrothermal features seen today at Yellowstone National Park. The study of hydrothermalism in ancient settings and its impact on hominin evolution has not been addressed before, although the association of thermal springs in the proximity of archaeological sites documented here can also be found at other localities. The hydrothermal features and resources present at Olduvai Gorge may have allowed early hominins to thermally process edible plants and meat, supporting the possibility of a prefire stage of human evolution.

AB - Landscape-scale reconstructions of ancient environments within the cradle of humanity may reveal insights into the relationship between early hominins and the changing resources around them. Many studies of Olduvai Gorge during Pliocene-Pleistocene times have revealed the presence of precession-driven wet-dry cycles atop a general aridification trend, though may underestimate the impact of local-scale conditions on early hominins, who likely experienced a varied and more dynamic landscape. Fossil lipid biomarkers from ancient plants and microbes encode information about their surroundings via their molecular structures and composition, and thus can shed light on past environments. Here, we employ fossil lipid biomarkers to study the paleolandscape at Olduvai Gorge at the emergence of the Acheulean technology, 1.7 Ma, through the Lower Augitic Sandstones layer. In the context of the expansion of savanna grasslands, our results represent a resource-rich mosaic ecosystem populated by groundwater-fed rivers, aquatic plants, angiosperm shrublands, and edible plants. Evidence of a geothermally active landscape is reported via an unusual biomarker distribution consistent with the presence of hydrothermal features seen today at Yellowstone National Park. The study of hydrothermalism in ancient settings and its impact on hominin evolution has not been addressed before, although the association of thermal springs in the proximity of archaeological sites documented here can also be found at other localities. The hydrothermal features and resources present at Olduvai Gorge may have allowed early hominins to thermally process edible plants and meat, supporting the possibility of a prefire stage of human evolution.

KW - biomarkers

KW - thermophiles

KW - hydrothermalism

KW - Olduvai Gorge

KW - paleoenvironment

KW - EARLY HUMAN HABITATS

KW - LOWERMOST-BED-II

KW - FLK-ZINJ

KW - OLDOWAN

KW - LIPIDS

KW - FRESH

KW - WATER

KW - RECONSTRUCTION

KW - PALEOLANDSCAPE

KW - COMMUNITIES

U2 - 10.1073/pnas.2004532117

DO - 10.1073/pnas.2004532117

M3 - Journal article

C2 - 32934140

VL - 117

SP - 24720

EP - 24728

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

SN - 0027-8424

IS - 40

ER -