Uncover the secrets of the "golden pit" full of pit goldware

Staff are carrying pit 5 items out of the warehouse.

Weighing more than 750 kilograms of dirt, it is tightly wrapped in wooden boxes and slowly rises out of the ground. When this "behemoth" was steadily moved to the cart next to it, there was warm applause at the scene.

This is the site of the overall cutting and relocation of Pit 5 in sanxingdui sacrifice area. On March 4th, after spending more than a month on the program study, simulated relocation and continuous cutting and packaging, the No. 5 pit of Sanxingdui Sacrifice Area successfully completed the overall cutting and successfully relocated to the Sanxingdui Museum Cultural Protection Center. In the future, laboratory archaeology will continue to be carried out on this "golden pit" where gold masks and a large number of gold leaf and ivory carving fragments have been found, and strive to uncover the secrets behind the gold artifacts in the pit.

Reasons for relocation

● After the excavation of the remains layer at the beginning of last year, the excavation of crater 5 is basically in a suspended state, and it is very difficult to carry out non-contact archaeological excavations

●There are many relics and fine fragments, and the combination relationship between relics cannot be determined, and it is difficult to extract on-site

●X-ray flaw detectors, CT and other inspection equipment cannot enter the pit to explore the remains layer

Relocation method

●Pit No. 5 is divided into two areas, No. 1 and No. 2, for cutting and relocating

●Before the overall cutting and relocation, the cultural security personnel carried out two 1:1 simulated relocations

Follow-up studies

● Extract cultural relics layer by layer, and each layer must be scanned with ultra-high precision or use CT and X-rays to record all the small cultural relics information

●Take soil samples for fine chemical analysis to see if there are traces of silk fabrics

Why relocate?

There are many cultural relics in the small area, which is inconvenient for on-site excavation

Pit 5 of the Sanxingdui Sacrifice Area is the smallest and most mysterious of the six newly discovered sacrifice pits last year.

During excavations early last year, a mutilated golden mask stunned the country. With the advancement of archaeological work, the beautiful bird-shaped gold leaf also showed its beauty. In addition, a gold crown, a large number of fine gold leaf and gold flakes scattered in Pit 5 were found, as well as exquisite fragments of ivory carvings engraved with string patterns, cloud thunder patterns, feather wing patterns and other ornaments.

However, after excavations to the remains layer early last year, excavations at Crater 5 were largely suspended. Because in the eyes of archaeologists and cultural protection experts, it is very difficult for pit 5 to carry out non-contact archaeological excavations. Li Haichao, a professor at the School of Archaeology and Archaeology of Sichuan University, who is the person in charge of the archaeological excavation site of Pit 5, introduced that Pit 5 is only about 3 square meters, and in addition to the gold mask extracted last year, a large number of gold leaf and ivory carving fragments are scattered in the pit. It is worth mentioning that the gold leaf has round holes and is arranged in an orderly manner, which may hide valuable information. In addition, pit 5 may also have micro-trace information that is difficult to identify with the naked eye.

These cultural relics have once triggered the bold imagination of experts - is the gold mask a decoration attached to the face of the Dali people? Is bird-shaped gold leaf worn around the neck as a decoration? Will the large amount of gold leaf be threaded through the rope and hung on the clothes in a string? Could they be symbols of status used by the devotees?

Archaeologists also found a large number of scattered gold beads in the pit, some of which were less than 1 millimeter in diameter, and some of which were not very large even under the microscope. These gold beads contain up to 99% gold, are they consciously made, or are they melted like this because of fire? Evidence is also needed.

Considering that there are many relics and fragments in Pit 5, the combination relationship between relics cannot be determined, the on-site extraction is difficult, and the X-ray flaw detector, CT and other detection equipment cannot enter the pit to explore the remains layer, experts believe that the archaeological excavation of Pit 5 has been unable to meet its excavation, protection, research and other conditions, and it is necessary to relocate to the laboratory to carry out more scientific and refined extraction and protection research by taking the overall split extraction method. The plan of cutting and relocating back to the laboratory archaeology has been affirmed by Li Cunxin, a well-known cultural protection expert at the Institute of Archaeology of the Chinese Academy of Social Sciences, and others.

How does the relocation work?

Two simulations to ensure that nothing goes wrong

On January 17, pit 5 was divided into two areas, No. 1 and No. 2, and began to be divided and relocated. Prior to this, the cultural security personnel carried out two 1:1 simulated relocations, which solved the problems of not destroying the pit wall and the distribution of the remains, as well as the cutting process and the box reinforcement process.

It's a complex project.

Ren Junfeng, a cultural relics conservator at the Cultural Protection Center of the Provincial Institute of Cultural Relics and Archaeology, is the person in charge of the relocation site, and he introduced that there is almost only a few centimeters of space between the cut body of the no. 5 pit containing cultural relics and the pit wall, and the pit wall is not flat. In order to avoid damaging the pit wall and the cutting body, the staff can only slowly dig with a customized "large ear scoop" on the U-shaped operating platform. Fortunately, a cave in the northeast corner of Area 1 showed no artifacts buried, making it a valuable operating area for staff. After removing Area 1, fight for space to relocate Area 2.

The reporter saw at the scene that the microfilm tools customized by the cultural security personnel were various. The Luoyang shovel was transformed into a large and small shape, so that the shovel inserted into the soil could form a column to bring out the soil. When the pit wall and the cut body are separated, the cut body is first fixed with a border and the cut body is wrapped and moisturized with a film, and then an area is hollowed out with a "digging ear spoon" made of L-shaped steel, and then the load-bearing wooden board is inserted. When the bottom of the cut body is completely hollowed out, it has been loaded into a special cabinet.

On the afternoon of March 4, the cut-off body in the No. 2 area of pit 5 was hoisted. Under the action of the jack, the staff welded the outer frame angle steel to complete the "packing"; the spray kettle sprayed the welding joint at any time to avoid igniting the wood when the steel frame was welded on the spot. With the rotation of the small manual lifting robot hand pulling gourd gantry, the No. 5 pit body slowly came out of the pit.

"We completed this pit relocation exactly as requested by the archaeologists." When the No. 5 pit was successfully moved out of the archaeological area, Ren Junfeng was already sweating when he took off his protective clothing, "scientific construction ensured that the cut body did not collapse and break, and did not destroy the pit wall at all, retaining the original information when the ancients excavated." ”

What about the follow-up work?

Laboratory archaeology, discovering more unknowns

The golden mask found in Pit 5 stunned the country, but in the eyes of archaeologists, the archaeological excavation work of Pit 5 was only 20% complete, and a lot of work remained to be carried out in the laboratory.

After the No. 5 pit cutter was removed from the pit, the cultural security personnel quickly sent it to the Sanxingdui Museum Cultural Protection Center. In the future, related archaeological excavations will be carried out here.

According to Li Haichao, the gold leaf and newly discovered axe-shaped gold artifacts exposed in March last year are still lying motionless in the mud. The axe-shaped gold ware is the largest gold object found in Pit 5 after the gold mask, and the overall shape is like an axe, with an arc-shaped blade at the front end and several regular grooves on the surface. Compared with most of the gold artifacts previously unearthed in the Sanxingdui Sacrifice Area, the biggest feature of this axe-shaped gold artifact is that it is thick and thick, and the thickest place is more than 3 mm. When it first appeared last year, some experts speculated that it might be a symbol of power based on its shape. If it were a golden mask, it would be a testament to the incomparable status of their owners, together with the golden mask.

All the secrets are waiting to be revealed one by one in the laboratory.

"If you are archaeology at the site, you can only look from top to bottom, and you can only look for it with the naked eye, even if it is not good with a microscope." Li Haichao said that after moving to the laboratory, there will be many more methods and equipment available. "We will extract cultural relics layer by layer, and each layer will be scanned with ultra-high precision or ct or X-ray to record all the small cultural relics information." In addition, soil samples are taken for fine chemical analysis to see if there are traces of silk fabrics. "It is reported that the excavation time of Pit 5 may be as long as one year. (Sichuan Daily all-media reporter Wu Xiaoling)