Urbanizing Forest: Archaeological Evidence from Southern Bénin

Until recently archaeological evidence predating the historically known Kingdom of Dahomey in southern Bénin has been next to non-existent. The situation changed when deep and long drainage channels were dug into the fertile soils at the modern town of Bohicon. In the sides of these channels, rich cultural remains appeared, confirming the assumption that high rates of soil accumulation have caused low archaeological visibility in the forest/former forest belt of West Africa. Geophysical mapping and extensive excavations have revealed two large settlements of 500-600 hectares each, partly overlapping but separated by 2000 years. This paper presents both sites – Sodohomé 1, the earliest site encountered so far in southern Bénin, and Sodohomé 2 (or Sodohomé-Bohicon) which dates to AD 900-1150/1220. Although the first has produced some remarkable results, for instance, an iron spearhead that is the oldest securely dated non-meteoritic iron object in Africa known so far, the focus is on the latter site where evidence demonstrates the existence of a true town with craft specialisation, industrial-scale iron production, long-distance trade and wide communication networks.

Meteorite impacts on ancient oceans opened up multiple NH3 production pathways

A recent series of shock experiments by Nakazawa et al. starting in 2005 (e.g. [Nakazawa et al., Earth Planet. Sci. Lett., 2005, 235, 356]) suggested that meteorite impacts on ancient oceans would have yielded a considerable amount of NH3 to the early Earth from atmospheric N2 and oceanic H2O through reduction by meteoritic iron.

Meanwhile, Back at Brookhaven

At the end of the Nineteenth century William Ramsay, searching for minerals that might concentrate argon or helium, wrote, “One mineral—malacone—gave appreciable quantities of argon; and it is noteworthy that argon was not found except in it (and, curiously, in much larger amount than helium), and in a specimen of meteoric iron. Other specimens of meteoric iron were examined, but were found to contain mainly hydrogen, with no trace of either argon or helium. It is probable that the sources of meteorites might be traced in this manner, and that each could be relegated to its particular swarm.” Finally, sixty years later, this is what Ollie Schaeffer and I now set out to do. Meteoritic iron has been used since prehistoric times: necklaces of the metal beads interlaced with gold are found in the tombs of Egyptian kings, and an inventory of a Hittite temple, describing where on earth their gold and silver came from, lists their iron as having “fallen from the sky.” Yet as late as the early nineteenth century, the reality of meteorites still was not accepted by men of good will. For after all, how could heavy stones and chunks of iron fall out of the sky? And then in 1803 a huge shower of meteorites fell at L’Aigle, France, just at the time that the French Academy of Sciences had convened a meeting to discuss the question. In America no one paid much attention, until on December 14, 1807, at 6:30 in the morning, a bright fireball suddenly blazed through the sky over Vermont and Massachusetts. It was reportedly nearly as bright and big as the moon, until it suddenly exploded and disappeared over the town of Weston, Connecticut, showering the area with stone fragments, as the local media reported. In those days it took a while for the news to travel a few tens of miles, and so it was a few days before Yale’s new professor of chymistry (sic) and natural history, Benjamin Silliman, heard of it. Grabbing his hat and a colleague, Professor James L. Kingsley, he galloped across the state to Weston.