Ah, the Palacio de Ocomo (20°44'43.93"N 104° 9'51.77"W). I've never actually been to the site itself despite being in the Magdalena Lake Basin for five months. That pesky survey took up most of my time. I did, however, survey most of the rest of the hilltop the Palacio is located on and we found a ton of stuff which was really neat. Mostly terraces, habitational platforms, and metates/manos. But there were some larger constructions, as well. Nothing as large as the Palacio, however.

Short experience aside, I'm going to call bunk on the Mexconnect article and its claims for iron working for two reasons. The first is that Phil Weigand has been the only person to really publish anything about the Palacio and he made no mention of evidence of iron working. But then, he never did excavate the site. He merely identified it to be a rather large structure that postdated the guachimontones of the Classic period. This rather abrupt change in architecture, along with changes in burial style, ceramic types, and lithic tools, may have actually be the result of a migration from the Bajio or other nearby areas due to drought.

Second is that the archaeologist that is excavating the site, Sean Montgomery Smith, hasn't published anything about the site despite having been excavating for several years. Here is a little video in which he talks about the site (it's in Spanish). Now, perhaps Mexconnect somehow got a hold of an informe or even interviewed Monty and that's how they came about the information. I can't really say. If something like that were discovered I would be very surprised that Monty would sit on such a discovery and not publish anything on it. Iron working in Mesoamerica before contact just didn't exist and this would certainly be groundbreaking.

Metallurgy certainly did exist in the Epiclassic in Jalisco, but it was restricted to things like copper bells. Bells have been found at Amapa, Nayarit and Atoyac, Jalisco for example, among other sites across West Mexico. A brickmaker behind the town of Etzatlan, where we stayed during the survey, has been digging into a rather large Postclassic deposit of sherds. There were some beautiful polychrome pieces that were just cast aside. He did collect some of the items for his own collection and one of those items was a simple ceramic rattle. He claimed that he broke it open and found a nugget of gold inside that acted as a rattle. He sold the gold and that was how he was able to buy his truck (which admittedly was a really nice truck for being a brickmaker). I've heard reports of other gold items or nuggets, but nothing for iron.

So I've been reading this excavation report/book Excavations at Cojumatlan, Michoacan, Mexico by Robert H. Lister (1949). Lister found iron objects at Cojumatlan, a site located on the southeastern shore of Lake Chapala.

Pages 72-73:

"Objects of Iron

The objects of iron were thought to be manufactured of iron pyrites, but on an analysis by Dr. E. L. Martin of the Chemistry Department, University of New Mexico, they proved to be an oxide of iron.

Beads. About the neck of Burial 8 was a necklace of seventy-nine discoidal iron beads. They measure 4 mm in diameter and average 2 mm in thickness. Each specimen has been drilled from both surfaces.

A single disc-shaped bead was associated with Burial 9. It is larger than the other specimens, being 9 mm in diameter and 4 mm in thickness. It also has been drilled from both surfaces.

Metal items, both copper and iron, were found from the surface down to Level 4, with their greatest frequency in Levels 3 (20-28 in below surface) and 4 (28-36 in below surface). This would place the use of metal in the Cojumatlan complex almost exclusively.

I looked up what these iron oxides could be and it includes things like magnetite, hematite, maghemite. Now, I don't know which specific oxide it is and Lister doesn't identity it further than being an oxide.

So, just a bit more info on iron-ish use in West Mexico if you're curious.

/u/Ucumu /u/Cozijo