The Akkadian Empire ruled over ancient Mesopotamia between the 24th and 22nd centuries BCE … until it mysteriously fell and disappeared. The answer to what happened may have finally been found in a stalagmite in a cave in Iran. Dragons? Giant bats? Small enemy soldiers who can see in the dark?
Researchers attempting to recreate events which occurred thousands of years ago often study soil samples, rock formations, glacier ice and other remnants of the era for evidence of what was going on both locally and globally at the time. A lesser-known but still reliable historic recording device is a speleothem – those cave structures formed in caves by the deposition of minerals from water that we like to call stalactites and stalagmites. As you may remember from elementary school, stalactites hang tightly from the cave ceiling while stalagmites might make it there someday as they grow on the cave floor. Not surprisingly, they might also last longer since they have less distance to fall. That’s the case in Gol-e-Zard Cave, located in the Alborz mountain range in northern Iran about 30 miles (50 km) from Tehran. The cave is popular with both explorers and tourists for its stunning stalactites and stalagmites and it’s there, hidden in an old stalagmite, that researchers might have found the secret to the mysterious fall of the Akkadian Empire.
The Akkadian Empire, with Ancient Egypt and the Indus Valley Civilization of India, is considered to be one of the three Bronze Age cradles of early civilization -- three civilizations which all ended at about the same time – suggesting to many researchers that a global catastrophic event may have been the cause. However, the historical records of the Akkadian Empire are scant, so speculative reasons considered for its fall include wrath of the gods, overpopulation, revolts, invasions nomadic incursions and mismanagement by leaders. Furthermore, there’s no evidence of a major atmosphere-changing volcano or catastrophic solar winds or even man-made apocalyptic events at the time. That led Dr. Stacy Carolin of Oxford University and a team of scientists into Gol-e-Zard Cave to study a stalagmite which was there well before the empire rose and fell.
“A speleothem geochemical record from northern Iran captures significant climate fluctuations during the mid-to-late Holocene at high resolution. Two abrupt shifts in Mg/Ca last for more than a century and are interpreted as enhanced dust activity, indicating a threshold behavior in response to aridity.”
The results of Carolin’s study were published last week in the Proceedings of the National Academy of Sciences and the title says it all: “Precise timing of abrupt increase in dust activity in the Middle East coincident with 4.2 ka social change.” Sharp spikes in the magnesium to calcium ratio in the stalagmite point were caused by increased dust in the Alborz mountains above the cave 4200 years ago (4.2 ka or kiloannum) -- dust caused by climate severe enough to result in the abandonment of the area and the demise of the Akkadian Empire.
“The extent to which climate change causes significant societal disruption remains controversial. An important example is the decline of the Akkadian Empire in northern Mesopotamia ∼4.2 ka, for which the existence of a coincident climate event is still uncertain. Here we present an Iranian stalagmite record spanning 5.2 ka to 3.7 ka, dated with 25 U/Th ages that provide an average age uncertainty of 31 y (1σ).”
Dr. Carolin knows the non-scientific sensitivity to looking at climate change as a cause for social change leading to the end of civilizations, so she points out that stalagmite measurements are far more precise than others – with an accuracy to within 31 years. Ba-zinga! End of story! Right?
“Collapse of Earliest Known Empire Is Linked to Long, Harsh Drought”
That’s the headline from a 1993 New York Times story about a the discovery of soil evidence which suggested that the Akkadian empire was ended by a 300-year drought and called it “the first time an abrupt climate change has been directly linked to the collapse of a thriving civilization." And yet, here scientists are 25 years later still trying to prove it to a non-scientific climate-change-skeptical public and leaders who pander rather than accept facts.
Where will we be 25 years from now? Where will OUR civilization be?