As for the lack of written records in Sanxingdui, I personally think this is normal in early civilizations. The formation of writing probably occurred in the middle and late Shang Dynasty. So far, no discoveries have been made in the early Shang Dynasty and surrounding civilizations. The formed characters are at most the transitional stage from early symbols to characters. Therefore, for Sanxingdui in this period, the growth of its civilization did not form writing. Perhaps we can find some symbols at most, and then we can only look forward to archaeological discoveries.
The first priority is to clarify the definition and scope of Chinese civilization. The Chinese nation is not a single nation, and Chinese civilization is not a civilization with a single element. From an ethnic point of view, the Chinese nation has been continuously integrating since the Neolithic Age. In the Xia and Shang Dynasties, the Huaxia ethnic group was formed. In the Han Dynasty, it continued to integrate until modern times, forming a nation composed of Han people and many ethnic minorities. of the Chinese nation.
From the perspective of civilization, the culture of the Chinese nation is diverse, which is related to the continuous ethnic integration in history. Therefore, Chinese civilization is not a single civilization, but is based on the early Central Plains region. The core radiates and communicates around, thus forming an inclusive and extensive civilization. According to current archeology and some records, in the early Three Dynasties period, that is, the pre-Shang and Xia dynasties, there was not only the Xia civilization in the Central Plains on the land of China, but many civilizations including the Xia civilization and the pre-Shang civilization* **The same existence. There are still a large number of secondary civilizations surrounding the Central Plains civilization, including many civilizations such as the Liangzhu Civilization and the Sanxingdui Civilization that everyone is familiar with recently. These surrounding civilizations were not isolated from the Central Plains civilization, but had exchanges with each other to varying degrees. This can be seen from the types of cultural relics unearthed.
In fact, some parts of the Sanxingdui Civilization have been excavated in the 1970s, such as the famous bronze tree, Zongmu Mask, etc., which have long been displayed in the museum. They were not excavated recently. The age of these cultural relics is basically consistent with the middle and late Shang Dynasty. There are no such exquisite cultural relics among the early cultural relics in Sanxingdui. From the cultural relics unearthed in Sanxingdui, we can see that Sanxingdui not only has unique characteristics that are different from the Central Plains civilization, but also has cultural characteristics from the Central Plains civilization. This shows that early Sanxingdui may have the same origin as the Central Plains civilization but different branches, and that there was a certain degree of exchange and integration with the Central Plains civilization in the middle and later stages.
Therefore, Sanxingdui is not completely independent of Chinese civilization, but a branch of early Chinese civilization and a part of Chinese civilization.