Bible-era grain sows seeds of contention.

Joshua ordered a trumpet blast, and the walls of Jericho came tumbling down, ending the Israelites' 40-year sojourn in the desert, the Bible says. Some archaeologists, however, hold that ancient Egyptian armies were responsible for sacking Jericho sometime between 1550 and 1300 B.C.

A pair of Dutch researchers now claims that cereal grains from Tell es-Sultan, the site of ancient Jericho, can provide an accurate date for the siege. The handful of blackened grains comes from a layer at the site scorched by fire, marking the destruction of Jericho. Radiocarbon testing indicates that the seeds are 3,311 years old-give or take 13 years-report Hendrik J. Bruins of the Ben-Gurion University of the Negev in Israel and Johannes van der Plicht of the University of Groningen in the Netherlands in the July 18 Nature. Although scientists cannot convert age in radiocarbon years directly to a calendar date, the researchers estimate that the Jericho layer containing the grains dates to around 1580 B.C.

They note the closeness of the grains' age to a radiocarbon age of 3,356 years for a huge volcanic eruption on the Aegean island of Thera. Scientists have linked that blast, which devastated Crete and blanketed the southeast Mediterranean with ash, to a plague described in the Bible as "darkness that can be felt" and to Egyptian accounts of dark skies at the same time. Researchers have determined the calendar date of the eruption as 1628 B.C. The difference of 45 years between the radiocarbon age of the grains and the eruption is "rather striking," Bruins and van der Plicht note. Moreover, the dates fit neatly with the biblical account, in which the exodus of the Jews from Egypt begins with plagues and ends 40 years later with the destruction of Jericho.

Radiocarbon dating is more art than science, says Cornell University archaeologist Maryanne Newton, who suggests that the 45-year interval seized on by the scientists rests on "a string of assumptions." The 13-year margin of error surrounding the Jericho date is a standard number referring to laboratory error, so the team's estimate could actually be off by a wider margin, she adds.

Bruins is now seeking to improve the correlation by comparing the radiocarbon age of the grains to more accurate tree-ring data (SN: 6/29/96, p. 405). This "may lead to truly absolute dating," he says.