A peek behind the masks

"The quality of the bronzeware could be even better than the items found in 1986," Lei says.

But "new" types of bronzeware raise more questions. For Lei, further study is still required to explain, for example, an animal decoration with an ox's head and a dragonlike body.

A 1.3-meter-high artifact, a kneeling human figurine carrying a vessel over its head, is also a puzzle.

"These mixtures reflect ancient Sanxingdui dwellers' brilliant imagination," Lei says.

On the subject of imagination, it is also expected that, as more cultural relics are unearthed, the ongoing excavation will also finally tether some of the wilder flights of fancy fueled by the discoveries at the site, says Zhao Congcang, a professor at Northwest University in Xi'an, Shaanxi province.

When the exotic and mysterious artifacts were first discovered in 1986, a myriad theories captured the public imagination, but none so compelling as that which claimed extraterrestrial influence on Sanxingdui culture.

"New archaeological findings could guide the public back to a scientific approach to figuring out the origins of Sanxingdui culture," Zhao says. "Cultures are created by people. If we can answer some questions about the people of Sanxingdui, the mysterious parts of their culture may be more easily decoded."