Judging from the form of tombs, Sanxingdui civilization was destroyed after a major invasion or natural disaster. The untidiness of tombs shows that burial is in a hurry, and more attention is paid to the destructive burial of objects. Maybe a writing carrier like Oracle Bone Inscriptions was burned or destroyed on the spot? At that time, it was inconceivable that such an advanced civilization had no words and records.

From the unearthed cultural relics, the exquisite bronzes, shells, coins and jade articles fully show that Sanxingdui civilization had full trade with foreign civilizations at that time, and Oracle Bone Inscriptions in the Central Plains will certainly spread to Sanxingdui civilization at that time.

Personally, I think the biggest reason why Sanxingdui is not recorded is that it was established by a civilization different from ours. Before this civilization could contact us, it disappeared in the long river of time for some unknown reasons. There are many speculations about Sanxingdui, either the imagination is too rich or it can't stand scrutiny.

Judging from the date of carbon 14 determination in Sanxingdui, this civilization overlaps with the Shang Dynasty in our history. But let alone written records, even related myths and legends. So I think this is a parallel civilization that has no intersection with us. As for the speculation about aliens, I think it's too wide of the mark to discuss.

Imagine that in Shang Dynasty, it didn't take long for human beings to enter civilized society. It is quite possible that two completely untouched civilizations exist at the same time. Sanxingdui was in Sichuan, and Shang Dynasty was in Qixian County, Henan Province. From the navigation point of view, the distance between the two places exceeds 1300 km. It takes 16 hours to drive. For people of that era, contact was completely normal.

There is no conclusive evidence as to whether Sanxingdui civilization is a vanished ancient Shu kingdom or a part of the ancient Xia Dynasty. However, the Sanxingdui site has only been excavated for two thousandths. I believe that with the continuous research and discovery of Samsung, we will certainly outline a more colorful, fuller and more integrated Chinese civilization at that time.