Catastrophes and deaths along Tanzania’s Western Indian Ocean coast during the Early Swahili period, AD 900–1100

ABSTRACT

Natural disasters such as floods, tropical cyclone storms, tsunamis and earthquakes had various kinds of effects on ancient societies around the world. In Eurasia and the Americas, the number of archaeological studies of these phenomena is increasing, particularly from geoarchaeological perspectives, but in East Africa few archaeological studies have yet been undertaken of their impacts on local communities. Archaeological and palaeoclimatic records nevertheless show that lowland settlements situated along the Western Indian Ocean seaboard occasionally flooded in the course of the late Holocene. This paper presents new archaeological evidence from Pangani Bay, northeast Tanzania, that suggests that flash floods occurred on the southern bank of the Pangani River c. 1000 years ago, resulting in the catastrophic destruction of an ancient village located near the river’s mouth. Excavations conducted at the site of Kimu have recovered human remains interbedded in deposits of probable flood origins. Dating evidence and geoarchaeological records lead to the conclusion that Kimu was probably occupied during a period of climatic aridity prior to the flood event that destroyed the site and appears to have led to the death of its occupants en masse.

RÉSUMÉ

Les catastrophes naturelles ont eu divers types d'effet sur les sociétés anciennes autour du monde. En Eurasie et en Amérique, le nombre d'études archéologiques de ces phénomènes augmente, particulièrement du point de vue géoarchéologique, mais en Afrique de l'Est peu d'études archéologiques ont été menées sur les impacts sur les communautés locales des catastrophes naturelles passées (inondations, cyclones tropicaux, tsunamis, tremblements de terre). Les archives archéologiques et paléoclimatiques montrent néanmoins que les zones de basse altitude situées le long de la côte occidentale de l'océan Indien ont parfois été inondées au cours de l'Holocène tardif. Cet article présente de nouvelles données archéologiques provenant de la baie de Pangani, au nord-est de la Tanzanie, qui suggèrent que des crues soudaines se produisirent sur la rive sud de la rivière Pangani il y a 1000 ans environ, entraînant la destruction catastrophique d'un ancien village situé près de l'embouchure de la rivière. Les fouilles menées sur le site de Kimu ont permis de retrouver des restes humains interstratifiés dans des gisements qui résultent probablement d’inondations. Sur la base des datations et de données géoarchéologiques, l'étude conclut que Kimu fut probablement occupé pendant une période d'aridité climatique antérieure à l'inondation qui détruisit le site, ce qui semble avoir décimé les habitants du village.

KEYWORDS:

• Late Holocene
• Early Swahili culture
• burials
• disaster archaeology
• extreme palaeoclimate
• palaeoflood

Acknowledgements

This research was supported by generous grants from the American Council of Learned Societies (ACLS) through the African Humanities Program (AHP) for the 2016/2017 Postdoctoral Fellowship. I would like to thank Dr Charles Saanane and Dr Thomas Biginagwa from the University of Dar es Salaam for helping me to retrieve osteological information from the skeletal human remains. Prof. Bertram Mapunda is thanked for his guidance during the excavation process and his careful examination of the iron bracelets worn by one of the people from the burial ground. I also thank the Volkswagen Foundation of Hannover, Germany, which has a program aimed at supporting humanities postdoctoral fellowships in Africa, for providing me with funds for laboratory radiocarbon dating of samples collected from Kimu, Dr Danielson Kisanga from the Department of Geography of the University of Dar es Salaam for helping me to recover and process soil samples for geo-chemical analysis and Dr Elgidius Ichumbaki and Prof. Paul Lane for the constructive comments that helped to improve the quality of the manuscript. Finally, I am grateful to the Tanzania Department of Antiquities for the research permit and excavation license that enabled me to undertake fieldwork at Pangani Bay.

Notes on contributor

Elinaza Mjema is Lecturer in the Department of Archaeology and Heritage Studies, College of Humanities, University of Dar es Salaam, Tanzania. He completed his PhD on the settlement history of the Pangani Bay area of Tanzania at Goethe University, Frankfurt-am-Main, Germany, in 2015.