A tomb adorned with carvings of mythical creatures has been found in a 1,700-year-old cemetery on the Silk Road, the ancient trade route that once linked China to the West.

Archaeologists discovered the cemetery near the northwestern Chinese city of Kucha and excavated 10 tombs, many of them impressive brick structures.

One of the tombs featured carvings of four symbols from Chinese mythology: the Black Turtle of the North, the Vermilion Bird of the South, the Azure Dragon of the East and the White Tiger of the West, researchers have reported.

The figures represent the seasons and different parts of the heavens, with divisions across the night sky equivalent to the constellations of the zodiac in Western astronomy, they said.

Although first excavated in 2007 and reported in a Chinese science journal, the study has only now been published in the English language journal Chinese Cultural Relics, a new journal featuring translations from the Chinese.

The discovery of the Kucha cemetery was a feature of its inaugural November 2014 issue.

The tomb with the carvings, dubbed "M3" by archaeologists, "consists of a burial mound, ramp, sealed gate, tomb entrance, screen walls, passage, burial chamber and side chamber," said scientists with the Xinjiang Archaeological Institute.

Although the extensive brick tombs were probably constructed for wealthy people, the identity of those buried within is a mystery, the researchers say, since the tombs show evidence of having been robbed numerous times in the past.

There is also evidence that the tombs have been reused over time, with some of them containing the remains of more than 10 occupants.

Those "repeated multiple burials warrant further study," the researchers wrote.

Kucha was the center of an ancient Buddhist kingdom, located on a branch of the Silk Road that put it in contact with the rest of China and Central Asia and the cultures of Persia and India.

The kingdom was strategically located for controlling China's western frontier region known as Xiyu, important to Chinese rulers because many of the Silk Road trade routes traversed the area.

The Silk Road was not one single route, but rather a series or network of routes linking Eastern Asia with the Middle East and then on to Europe.

With its location on the northern edge of the Taklamakan Desert in China's Tarim Basin, Kucha represented a key location on one of the most northerly of the Silk Road routes.