Anthropology

When one chisels into rock, tiny bits of the chisel get deposited onto the 'walls'/sides of. the cavity. The chisel may be made of bronze (copper and tin), iron, rarely another stone. This is why chisels wear out. Modern techniques can identify just a few atoms, even to recognize impurities in the bronze (lead, antimony,. .. )

Until the chisel marks are fully identified as to elemental composition, we suspect hoax. (Hoaxers never get the Cu 63/65 ratio right.)