"A Survey of the Copper Age," T. M. Munchhkauser, Journal of Tsalal Studies, Lethridge Press, Alberta.

"A Survey of the Copper Age," T. M. Munchhkauser, Journal of Tsalal Studies, Lethridge Press, Alberta.

Metallurgy in Antarctica begins with clay.

Pottery and clay, mostly sun baked, had been in use in Antarctica since at least the beginning of the middle human era. Some figurines and pottery shards may date back as early as 22,000 years ago, but these early efforts seem transitory, the cultures which developed them dying off without passing on their skills. However, shortly after the development and spread of agriculture, sun baked pottery, sometimes lightly fire touched, also proliferated and became common.

Fired and glazed ceramics, however, did not emerge until the beginnings of the Copper Age period, simultaneously in several places, becoming particularly widespread in Tsalmothua. Indeed, ceramics spread so widely, so quickly and became so integral to life in so many regions that some scholars have argued that the Copper and Bronze Ages should be termed the Ceramic Age.

Key to fire and glazed ceramics were the development of forced air/vented ovens which had begun to proliferate in the sunken cities of Tsalmothua. For the underground towns and villages, fire and smoke was an ever present hazard. Archeological digs from the Coal Age show that runaway fires destroyed or damaged several communities. Other communities show little sign of damage, but records and oral histories report mass fatalities through smoke death or bad air. Over time, the sunken cities devised various solutions to the problem of fire, eventually developing ovens which had their own duct systems for forcing surface air and venting smoke. These ovens allowed for more precise control of fires and heating than ever before, and as a collateral issue, allowed extremely high temperatures eventually up to two thousand degrees fahrenheit to be reached quickly and maintained.

Ceramics production reached an extremely high level of development in the Tsalmothua sunken cities, particularly in Tcho Tcho, but many other centers are known. A remarkable Tsalmothua innovation was interlocking ceramic pipes used for water carrying and air venting, which soon became a staple feature of sunken cities architecture. These pipes featured the first molded screw threads and interlocking components.

Throughout the metal ages, ceramic technology in Tsalmothua continued to develop, producing artifacts of exceeding complexity and for a multitude of uses. The Tsalmothua made various efforts to strengthen and reinforce ceramic products, and experimented with ‘compound artifacts’ mixing and mingling ceramics, woods, leather, bone and stone. Development of ceramics reached its peak shortly before the Iron Age.

Metallurgy begins with copper. Copper is a soft malleable metal which can be found formed into nuggets. Copper melts at roughly 1981 degrees fahrenheit. An ordinary wood fire ranges 800 to 900 degrees fahrenheit. doesn’t raise the temperature of copper enough to melt it. But it does make it soft and malleable, allowing it to be pounded, honed and shaped into tools, weapons and ornaments. In North America, the Great Lakes copper complex gives us a glimpse into a near neolithic copper culture, seasonally occupying and digging out nuggets for thousands of years.

In Antarctica, copper use emerges in some areas as early as the later parts of the Middle Human Era, most notably the Zhudan, the upper regions of Tsalmothua and independently in Tsorle and the upper country. The copper mined during this time were placer deposits, washed down by stream, with occasional digging. For the most part, these efforts were sporadic and tended to die out.

Copper ornaments became highly prized and passed from hand to hand for centuries, particularly among the Coal Kings. However, the coal kings tended to discourage extensive copper works in territories that they influenced, seeing such developments as a threat to their power. Minor production of hammered copper did continue until the formal copper age, when, ironically, it petered out.

The Yag basin, essentially an alluvial flood plain, had no mineral deposits. But some of the upriver Yag communities traded copper and gold with hill country tribes for a time, until the Ptarh exterminated them.

Unsurprisingly, the Zhudan were the first culture to make extensive use of hammered copper. Their territories had the richest copper deposits in the Antarctic and there were extensive fields of copper nuggets.

Unlike the Coal Kingdoms, the Zhudan tribes were relatively decentralized, though they had informal trading networks, and obtained their fuel from harvesting peat and driftwood. The Zhudan began production of copper initially for jewelry, but soon elaborated into copper axe heads, spear heads and arrow heads. Copper became ubiquitous in Zhudan society and became in integral part of their ship manufactury.

Approximately 4500 BP widespread copper shortages, the result of local fields being harvested out and loss of copper through trading and ship losses, began to occur. Around this time, the Zhudan began employing Tsalmothua style ovens, based on sunken cities principles of forced air flow. The greater temperatures of these ovens allowed copper to melt completely, and from there, it was a short step to melting ores.

Copper smelting spread widely through the Zhudan territories, and were adopted by Lake Vos and Azul cultures. Trading networks saw copper artifacts being imported extensively by both the Copper Kingdoms and the Yag. Only the Ptarh strongly eschewed copper.

Zhudan remained the center of copper production through the copper age, roughly 4500 BP to 4300. By the end of the copper age, rival production centers in Lake Vos and Tsorle were as large or larger.

The copper age also saw the discovery and development of Gold. Like Copper, it was originally found in nuggets and in placer deposits, and had some use in the later parts of the Middle Human Era. Softer and more malleable than copper, it was used for ornamental and decorative purposes mostly. Gold smelting began almost immediately in the copper age, and there is evidence of gold/copper alloys dating from the middle of the age.

By the end of the copper age, several additional metals had been smelted and come into use: Silver, Tin, Lead and Zinc.

Oddly, copper smelting, or for that matter, any other metal smelting, does not seem to have caught on at all in Tsalmothua, which excelled in ceramics, and whose fire management techniques underlay most early smelting technology. It appears that the Tsalmothua preferred ceramics, in part becaus of the ready availability of clay almost everywhere, and the scarcity of metals except in specific areas. Smelting metal was also unpopular, copper smelting in particular tended to produce toxic arsenical fumes which were all too prone to seepage.. Most fire pits or ovens in Tsalmothua communities tended to be central and multi-functional. The idea of a segregated vented smelting area did not gain much popularity. Firing clay was relatively safe, smelting metal much less so.

It’s also speculated that the economics of fuel worked against Copper smelting. The Coal Kings charged dearly for their coal, and the relative cost of energy in these communities was quite high. Few Tsalmothua communities outside the coal networks had the surplus energy to engage in smelting, and few within the coal networks had the wealth to spare for such a venture. For their part, the Coal Kingdoms were actively hostile to indigenous metalworking or resource extraction which they themselves did not control.

Glass also appeared late in the Copper Age, in the Azul region, and remained unique to Azul well into the Bronze Age, when other cultures began to develop their own glass techniques. Azul Glass remained superior in technique and technology for well over a thousand years. Nevertheless, the earliest known glass ovens of the Azul closely resembles Tsalmothua models.

The copper age is generally accorded to run from 4500 BP to 4200 BP, with the bronze age running from roughly 4200 BP to 2100 BP. However, these distinctions are rather arbitrary. Bronze is merely a copper alloy, either arsenical bronze or an alloy of tin. The first copper alloys, emerge as far back as 4400 BP and are relatively widespread by 4300. The first known bronze actually dates to 150 years before the Bronze age.

-

Very plausibly detailed.

However, what would the incentive be to raise the temperatures in the stoves? Do they use any artificial means to enhance heat transfer in the underground cities?

-

That wasn't so much a goal as a by product. Essentially, the old style ovens developed in the sunken cities drew their oxygen from the normal environment. Basically, they were drawing their air from the same supply that people were breathing. However, in the underground, especially in the early sunken cities, air circulation was passive, and often relatively poor.

This lead to unfortunate situations where fires tended to consume available oxygen, leading to asphyxiation or to low oxygen situations. Low oxygen situations were even worse. A fire feeding on insufficient oxygen produced a poor quality, low intensity flame, which generated carbon monoxide, a gas of nearly the same weight as oxygen, and which tended to easily replace oxygen and pool at lower levels, with fatal consequences.

Initial Tsalal efforts to deal with this problem were in the form of experiments, locating the ovens at different sites within the urban complex, sometimes tops, sometimes bottoms, sometimes on the edges. Elaborate chimneys were built. At some point, relatively early, it was realized that fires burned better with steady fresh air. So elaborate air intakes began to be built to funnel wind or fresh air into the fire chambers.

Controlling air flow allowed greater control of the fire. The initial benefit of this was to allow more control over energy use. Coal was expensive, so by reducing the air intake (having made sure to ensure proper exhaust venting) you could reduce the intensity of the fire and slow the burning down to minimal levels. Then, by simply increasing the airflow, and adding fuel, you could ramp up fires to useful levels for cooking and heating.

Developing hotter fires was not an objective. And indeed, the sunken cities of Tsalmothua tended to avoid extremely hot fires as these were seen as wasteful. As I've noted, the Tsalmothua cultures were very slow to exploit their metallurgical potentials, even though they'd created the key piece of technology.

The Zhudan adapted Tsalmothua ovens and forced air fires originally to soften copper and cold nuggets and make them malleable for hammering and shaping. However, the design principles of the Tsalmothua ovens made hotter fires very feasible. The Zhudan would seek a quick hot fire as quickly as possible to work their copper. They did not anticipate that their fires would become so hot as to actually cause the copper to melt. And when it happened, it was initially an unwelcome development. They'd lose perfectly good nuggets, melting away into slag mixed with ashes. The Zhudan became very concerned with temperature control, trying to make sure that the fires didn't get too hot.

However, when copper shortages took hold, some brilliant Zhu craftsman realized that the problem could become a solution. The same temperatures that turned fine nuggets into ash contaminated slag, could be used to separate ores from gravel and turn out pure copper. All that was needed was a means of channeling or catching it.