Book of Mormon readers will notice that the phrasing in 3 Nephi 28:12 ("he departed") is not only very similar to 3 Nephi 18:39 which says, "he departed from them, and ascended into heaven." but can be understood to imply the same.
If we assume a Mesoamerican setting, one statement by the 16th Century writer Ixtlilxochitl points out that after Quetzalcoatl had taught his people, he "ascended" from them at Coatzacoalcos. (Ixtlilxochitl:39). The city of Coatzacoalcos today is in the state of Veracruz, Mexico, just across the Coatzacoalcos River by the Gulf of Mexico. We will first address Christ's connection with Quetzalcoatl, and second the connection of Coatzacoalcos with Quetzalcoatl's ascension.
According to Garth Norman, a tenth-century Mexican culture hero called Ce Acatl Topiltzin Quetzalcoatl took upon himself the title of the deity Quetzalcoatl. There is good reason to believe that this man-god, who was a priest king of Tula, was regarded as an incarnation of the original god Quetzalcoatl, and significant historic events in his life may have been designed to convey that meaning. . . . We find that the name Coatzacoalcos, the place where Quetzalcoatl Topiltzin went for his departure, is from quequetzalco meaning "successor of Quetzalcoatl." The event and name were so important that a great river where he departed retains the name. Note the implication from this name that Quetzalcoatl Topilzin is "the successor of Quetzalcoatl."
So who was the original Quetzalcoatl, and did he have anything to do with this territory? The Rio Coatzacoalcos waters the land most serious students of Mesoamerican Book of Mormon geography recognize as the land of Bountiful where Christ ministered to Book of Mormon peoples after his resurrection (see 3 Nephi 11:1). This correspondence implies that the river may have been previously named Quetzalcoatl or another name from which it was translated. The literal meaning of the name Quetzalcoatl is "raised up serpent," which is a dead ringer for the brazen serpent raised on a staff that Moses gave to the children of Israel as an emblem for Jehovah-Christ.
We previously explored the meaning of the native name Tabasco for the lowland Bountiful territory that borders eastward from the Coatzacoalcos drainage. I showed that Tabasco means Bountiful and can be constructed as a composite of two words in Hebrew, tob and sho'a, that mean Bountiful. (See AAF Newsletter Nos. 5 and 6).
The implication is all too obvious. The reason Quetzalcoatl Topiltzin made that long journey from Tula to this particular location for his departure has always been a mystery. But it makes perfect sense in a Book of Mormon context as a pilgrimage to the place where the first Quetzalcoatl (Christ) departed (3 Nephi 28:12) and promised to return (3 Nephi 28:7-8). [V. Garth Norman, "The Case for Quetzalcoatl-Christ and Where He Administered Is Growing," in Ancient America Foundation Newsletter, No. 14 September 1998, pp. 6-7] [See the commentary on 3 Nephi 11:1; 3 Nephi 28:7]