Mesoamerican Pottery

[gtaggart]

Beastie, on the metallurgy thread, wrote the following:

I am extremely skeptical that evidence of metallurgy during the BoM time frame will ever be discovered in Mesoamerica, because their pottery shows that they did not have the ability to control heat at the high levels required.

Given that there is evidence of fired bricks and/or pottery in Mesoamerica in the relevant time period--I've read of fired bricks in Comalcalco, for example--what type of firing and at what temperature should we expect to find in order to support the claim that there was metallurgy in Mesoamerica during Book of Mormon times? For example, the melting points of copper, gold, silver, tin, and lead all fall within the temperatures that Dr. Clark Wernecke speculates were used to fire those bricks at Comalcalco.

Please understand: I'm not trying to prove metallurgy here, and I don't want this thread to descend into an argument over whether archeologists have found evidence of metallurgy.

Let's keep the discussion to pottery, bricks, and other fired objects and to what we have and what would be needed to support a claim for metallurgy in Mesoamerica.

[beastie]

gtaggart,

I'm going to be gone for a while today and won't be back to respond until late tonight or possibly tomorrow.

[gtaggart]

gtaggart,

I'm going to be gone for a while today and won't be back to respond until late tonight or possibly tomorrow.

That's fine because I have little or no time to be on here either.

[beastie]

First, I'll share this information from my website here:

http://www.mormonmesoamerica.com/metallurgy.htm

There are other ways to detect the possibility of a smelting technology other than looking for the artifacts and smelting operations. The ability to smelt metals is directly related to the ability to create and maintain heat at a very high temperature. Again, in From the Fiery Furnace, page 10: (this is a lengthy citation, but necessary to fully understand the connection between pottery and advanced metallurgy.)

One other possibility, which is gaining increasing credibility, derives strong support from two historical facts: both smelting and pottery making appeared in Neolithic life at about the same time, and the potter, the first specialist in the management of heat, had under his control all the materials and conditions necessary for the smelting of copper.

The history of pottery making is concerned, like smelting, with the transformation of materials by the application of heat. It no doubt began with the observation that clay is soft and easily shaped while wet, but dries hard in the sun; if wetted again, of course, it softens once more. The natural progression might have been to reinforce or emphasize the drying process in a fire. And so, by about nine or ten thousand years ago, it became known that when clay is fired to about 450 C it undergoes a chemical change and becomes irreversibly hard and water-proof. Above about 1400 C it undergoes a second change: the silica in the clay takes on a glassy structure, and the pottery becomes even more rigid.

At first, pots were heat-treated in open fires. In many parts of the world, including New Guinea, they still are. Later it was found that more predictable results could be obtained by stacking the pots on top of the fuel before lighting it, and covering the pile with earth or other material to keep in the heat and distribute it more evenly. Eventually it was realized that a permanent cover, with a built-in flue, was more efficient than making temporary piles for each firing. Thus, somewhere around the beginning of the sixth millennium BC, the pottery kiln came into existence.

With its thick, heat-retaining walls and flue-assisted natural draught, the pottery kiln could maintain temperatures well in excess of 1000 C for hours. In the enclosed space the fumes from the fire would tend to create a reducing atmosphere. Two of the conditions necessary for the smelting of copper were present. And so, on occasion, was the third requirement: the copper ores themselves.

Very early in the history of pottery, metallic ores had come into use for decoration, perhaps as a direct continuation of the tribal custom of body painting with ground-up mineral ores. The pigments were applied to the pots in liquid form, covered with a glaze â?? usually made with a lead oxide base â?? and fired. The pigments took on bright, permanent colours, and the glaze formed a hard, transparent protective coating.

There are many ways where pots are still decorated with metallic ores in this way, and fired in kilns whose design has hardly changed in thousands of years. One is Jarasthan, in northern India. The traditional brightly patterned â??blue potteryâ?? produced in and around Jaipur, the capital, is derived form the Islamic style of pottery introduced into India in the sixteenth century. Today there are scores of potter continually engaged, but one who stands out because of his technical grasp of pottery making and the behavior of metallic pigments is Kripal Singh. His work is in demand all round the world, and is remarkable for its consistency and quality. And yet, as he showed us, Kripal Singh still occasionally produces â?? quite unintentionally â?? smelted metal in his own kiln.

Kripal Singh uses many different metal ores for pigments, including copper, lead, iron, antimony, and cobalt. He makes his glaze by heating lead oxide crystals in the kiln. They melt down into a glassy substance which is ground into a powder, mixed with a binding agent, and applied to the decorated pots before firing. Sometimes Kripal Singh has to throw away a batch of melted-down glaze because it contains globules of pure metallic lead. More rarely, the transformation takes place later, during the firing of the pots, and produces patches of metallic lead in the layer of glaze.

(p 16) We cannot be sure, of course, that this is how the smelting process was first observed or contrived, but the repetitive nature of pottery firing and the conditions involved make it an obvious possibility. It may be more than coincidence that copper artefacts do not begin to appear in the archaeological record in any quantity until after pottery itself appears. And two areas where high-temperature pottery firing evolved â?? Mesopotamia and Egypt â?? went on to develop a high level of copper technology.

If it was in fact the pottery kiln which provided the first clues to smelting, it would soon have been appreciated that such a device was not ideal for the deliberate reduction of metallic ores. In the large are space the reducing gases were not evenly distributed, and much of the heat was wasted. So we can imagine people trying all kinds of methods of creating more effectively the conditions for smelting.

Many directions those early experiments took remain a mystery, but we do know that somewhere along the way the metal workers turned back to, or modified, the open fire. The walls of the fireplace were brought in closer to the fire and raised in height to make a more enclosed space, in which the reducing gases could be concentrated. The copper ore was brought closer to the source of the heat by mixing it with the burning charcoal. Air was blown into the heart of the furnace to raise the temperature. And, finally, other substances such as iron ore were added to the copper ore as a â??fluxâ??. Fluxing assists the reduction process, and improves the separation of the molten copper from the slag.â?

By this point in this essay, it should come as no surprise that the ability to create and maintain high heat in a kiln can be detected in pottery, and was not present in Mesoamerica during the Book of Mormon time frame.

Matheny comments upon this:

â??Karen Bruhns has explored the issue of early metals in southern Mesoamerica in a well-researched article and remarks that the Maya had some access to metal objects from the Early Classic period onwards. After a review of the information available about these early metal objects, she concludes that the â??only relatively certain statement that can be made is, with the possible exception of the Soconusco disksâ?¦ all Classic period metal objects found in Mesoamerica are obviously southeastern in manufactureâ? (1989, 221). This means that these artifacts were not made in the Maya area or in another region of Mesoamerica but in lower Central America.

If these metal objects were available to the Maya by at least Early Classic times, then the obvious problem becomes explaining why the Maya did not begin producing their own metal artifacts given the availability of gold, silver, and copper in eastern Guatemala, western Honduras, and El Salvador. Bruhns suggests that the southern Mesaoamericans lacked adequate pyrotechnology to make the transition to successful metallurgy (1989, 224). Specifically they lacked the technological prowess to attain and maintain the necessary temperatures to smelt metal. The ceramics from the area were fired in poorly controlled open fires, which often resulted in fire-clouding and incompletely oxidized areas. Only by the Late Classic and Early Postclassic periods does evidence exist that the Maya had begun producing ceramic vessels in controlled firing situations, including kilns. The adoption of the Central American metallurgical technology occurred in the Maya area soon after the production of Plumbate pottery began. Plumbate pottery has a vitrified surface and, according to Bruhns, the â??temperatures which produce the characteristic vitrification of Tohil Plumbate are precisely those which are appropriate for smelting.â? (1986, 226)â?