Strontium isoscape of sub-Saharan Africa allows tracing origins of victims of the transatlantic slave trade
Authors: Wang Xueye , Bocksberger Gaëlle , Arandjelovic Mimi , Agbor Anthony , Angedakin Samuel , Aubert Floris , Ayimisin Emmanuel Ayuk , Bailey Emma , Barubiyo Donatienne , Bessone Mattia , Bobe René , Bonnet Matthieu , Boucher Renée , Brazzola Gregory , Brewer Simon , Lee Kevin C. , Carvalho Susana , Chancellor Rebecca , Cipoletta Chloe , Cohen Heather , Copeland Sandi R. , Corogenes Katherine , Costa Ana Maria , Coupland Charlotte , Curran Bryan , de Ruiter Darryl J. , Deschner Tobias , Dieguez Paula , Dierks Karsten , Dilambaka Emmanuel , Dowd Dervla , Dunn Andrew , Egbe Villard Ebot , Finckh Manfred , Fruth Barbara , Gijanto Liza , Yuh Yisa Ginath , Goedmakers Annemarie , Gokee Cameron , Gomes Coelho Rui , Goodman Alan H. , Granjon Anne-Céline , Grimes Vaughan , Grueter Cyril C. , Haour Anne , Hedwig Daniela , Hermans Veerle , Hernandez-Aguilar R. Adriana , Hohmann Gottfried , Imong Inaoyom , Jeffery Kathryn J. , Jones Sorrel , Junker Jessica , Kadam Parag , Kambere Mbangi , Kambi Mohamed , Kienast Ivonne , Knudson Kelly J. , Langergraber Kevin E. , Lapeyre Vincent , Lapuente Juan , Larson Bradley , Lautenschläger Thea , le Roux Petrus , Leinert Vera , Llana Manuel , Logan Amanda , Lowry Brynn , Lüdecke Tina , Maretti Giovanna , Marrocoli Sergio , Fernandez Rumen , McNeill Patricia J. , Meier Amelia C. , Meller Paulina , Monroe J. Cameron , Morgan David , Mulindahabi Felix , Murai Mizuki , Neil Emily , Nicholl Sonia , Niyigaba Protais , Normand Emmanuelle , Ormsby Lucy Jayne , Diotoh Orume , Pacheco Liliana , Piel Alex , Preece Jodie , Regnaut Sebastien , Richard Francois G. , Richards Michael P. , Rundus Aaron , Sanz Crickette , Sommer Volker , Sponheimer Matt , Steele Teresa E. , Stewart Fiona A. , Tagg Nikki , Tédonzong Luc Roscelin , Tickle Alexander , Toubga Lassané , van Schijndel Joost , Vergnes Virginie , Njomen Nadege Wangue , Wessling Erin G. , Willie Jacob , Wittig Roman M. , Yurkiw Kyle , Zipkin Andrew M. , Zuberbühler Klaus , Kühl Hjalmar S. , Boesch Christophe , Oelze Vicky M. 
Published: December 2024

Strontium isotope (87Sr/86Sr) analysis with reference to strontium isotope landscapes (Sr isoscapes) allows reconstructing mobility and migration in archaeology, ecology, and forensics. However, despite the vast potential of research involving 87Sr/86Sr analysis particularly in Africa, Sr isoscapes remain unavailable for the largest parts of the continent. Here, we measure the 87Sr/86Sr ratios in 778 environmental samples from 24 African countries and combine this data with published data to model a bioavailable Sr isoscape for sub-Saharan Africa using random forest regression. We demonstrate the efficacy of this Sr isoscape, in combination with other lines of evidence, to trace the African roots of individuals from historic slavery contexts, particularly those with highly radiogenic 87Sr/86Sr ratios uncommon in the African Diaspora. Our study provides an extensive African 87Sr/86Sr dataset which includes scientifically marginalized regions of Africa, with significant implications for the archaeology of the transatlantic slave trade, wildlife ecology, conservation, and forensics.