A Harvard University study reports large-scale salt production occurred in inland China more than 2,000 years ago, the earliest date yet uncovered.
Salt is an important mineral for both nutrition and food preservation, and scientists believe salt production and trade are critical in the development of complex societies.
Harvard researcher Rowan Flad and colleagues said they found multiple lines of evidence of large-scale salt production at an archeological site near Zhongba, along the Yangzi River in central China.
The chemical compositions of the soil and nearby brine were found to be similar to other salt-production facilities. Likewise, the researchers said the form and composition of various ceramics found at the site are similar to salt production pottery discovered in other regions of the world.
The scientists say their study indicates salt production was a significant activity at the site during the first millennium B.C., and possibly earlier.
The article appears in this week's online early edition of the Proceedings of the National Academy of Sciences.
Copyright 2005 by United Press International
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