lakeview rud, on 07 January 2013 - 01:48 AM, said:
I think it was Ronald Reagan who told the old joke about digging through the pile of horse**** because somewhere under all that had to be a pony! In this case I hardly think Wakefield's effort (with 80 references!!) is crap. A fairly ridgid scholarly effort. So with all the name-calling and other BS going on in this thread, it still seems that there's some good proof that Michigan copper made its way to Europe somehow. So how about trying to figure out who and how? Or come up with a copper mining site in Europe capable of producing that type and purity of copper. If you find one then figure out how much copper was mined there and see if it fits the estimates of how much was used.
Wakefield's effort is crap, and it's not a rigid scholarly effort--it's an intentional lie. Let me demonstrate this by focusing on his discussion of the Uluburun shipwreck. First, here's the summary from the
first page of his article (emphasis added):
Quote
Recent scientific literature has come to the conclusion that the major source of the copper that swept through the European Bronze Age after 2500 BC is unknown. However, these studies claim that the 10 tons of copper oxhide ingots recovered from the late Bronze Age (1300 BC) Uluburun shipwreck off the coast of Turkey was “extraordinarily pure” (more than 99.5% pure), and that it was not the product of smelting from ore. The oxhides are all brittle “blister copper”, with voids, slag bits, and oxides, created when the oxhides were made in multiple pourings outdoors over wood fires. Only Michigan Copper is of this purity, and it is known to have been mined in enormous quantities during the Bronze Age.
The idea he presents is based on the fact that copper retrieved by the Amerindians from the Michigan area was very pure, elemental copper, meaning that they would find hunks of copper that they could take and cold hammer into objects--they did not have the technology to smelt copper from copper ore. So when he presents the data on the Uluburun shipwreck, he presents it to say that the copper was not from smelting. Observe (from page 3; emphasis added):
Quote
In the Hauptmann study, a steel chisel was used to cut pieces for surface sampling of 151 of the Uluburun ingots, and three oxhides and one bun were drill cored all the way through (see Fig.2). Their report states that he samples showed porous volume typical of “blister copper”, that “exceeds by far our previous ideas on their inner structure, with void volume reaching 20% or higher, especially in the upper portions of the ingots. In general, cavities like these, called “spratzen”, are caused by the effervescence of gases, such as oxygen, carbon monoxide, and carbon dioxide, by water from burning charcoal. This is in contrast with copper from other periods and other localities... All the ingots contain angular-shaped inclusions of iron-silicate slags, features compatible with natural rocks affected by the impact of high temperatures in the solid state. These can be removed by repeated melting, but, while these were regular steps … at many metallurgical sites all over the middle and southern part of Africa, the Uluburun ingots were not processed in this way. The angular shape of the slag inclusions, the structure, and the existence of iscorite point to a pouring of copper into a mold when the slag was already solidified… Interfaces in the crystalline structure of the ingots points to different batches during casting. Almost all the samples contained cuprite (Cu2O) distributed in changing amounts throughout the ingots, associated with large voids. The cuprite formed by corrosion in the sea does not penetrate for more than 5mm or so. An oxygen-rich atmosphere necessary to produce cuprite in an amount observed does not prevail during the smelting of (roasted) ores. We therefore can eliminate the conclusion that the ingots consist of as-smelted raw copper from a smelting furnace. Most of the ore available on Cyprus is of chalcopyritic composition, and relics of sulfides are quite difficult to completely remove, yet this mixed sulfide does not occur in the copper ingots.”
The Hauptman study concludes that “from a chemical point of view, the purity of the ingots is extraordinary in comparison with other sorts of copper from Wadi Arabah (high lead), from the Caucasus (high arsenic), from Oman (high arsenic and nickel). The ingots are made of pure copper, and all the ingots show a homogeneous composition. From our metallographic investigations, we are able to exclude a conscious purification or even a refining process to produce the ingots. We see few indications that bronze scrap could have been added, due to the very low tin concentration, and would not include gas bubbles and slag inclusions. The ingots provide an explanation for the previously vexing question of how an ingot of a metal as ductile as copper could have been broken up into small pieces such as those excavated by the hundreds in Sardinia. Two characteristics of the Uluburun ingots stand out – the presence of a substantial degree of porosity, and a high concentration of copper oxide inclusions, which made it brittle. Simply dropping the ingots onto a hard surface would easily shatter the ingots.”
You can see from the bolded parts that he's carefully selected text to support the idea that no smelting was involved in the production of this copper. The article he quotes from is "On the Structure and Composition of Copper and Tin Ingots Excavated from the Shipwreck of Uluburun" by Hauptmann et al. (2002). I've uploaded a copy of this for your perusal:
http://www.putlocker...2E34DAF6D741E2E
Now I will copy the portions of the Hauptmann article from which Wakefield quoted, and emphasize the parts that Wakefield actually used in order to demonstrate his purposeful manipulation. From pages 4-5:
Quote
Metallography of Copper Ingots
There are two persistent metallographic characteristics in just about all of the 151 samples of both
the oxhide and bun-shaped copper ingots. One is the
constant porosity, some large and some small, generally present in all the samples studied so far. The
other is the ubiquitous presence of different phases
and compounds inside the copper matrix.
Porous Volume of the Copper Ingots.
Through-out the samples we observed the porous volume
typical for “blister copper.” The ingots contain numerous cavities that can be classified in sizes of a
few micrometers up to several millimeters. It can be
demonstrated by the plugs drilled from the ingots
that copper oxhide and bun-shaped ingots of the
Late Bronze Age have an enormous porous volume
that exceeds by far our previous ideas on their inner
structure (figs. 1–5). The volume locally reaches
up to 20% or even higher. In general, cavities like
these are caused by the enervescence of gases such
as oxygen, carbon monoxide, and carbon dioxide, by
water from burning charcoal, as well as by sulfur
dioxide from oxidation of sulfide inclusions in the
copper in the liquid state. The gases dissolve violently during solidification, a phenomenon known in
metallurgy as “Spratzen” In addition, porous volume is caused all over the ingots by interdendritic
shrinkage (fig. 6). The porosity is high in the upper
part of the ingots. Near the bottom, the porous volume is low, the structure is more dense and hence
much less affected by corrosion over the millennia.
The distribution of the porous volume, in addition,
is irregular. This is exemplifed in the oxhide ingot
KW 1548/7b, where parts of dense copper alternate
with those high in bubbles and cavities (fig. 2) and
are sharply separated from each other. This could
be caused by pouring several batches of metal into
the mold to complete an ingot, an observation sup-
ported by macroscopic evidence (Pulak 2000: 142,
fig. 6).
As shown by previous studies (see above), the
high porosity seems to be a characteristic feature of
Late Bronze Age copper ingots with a provenance
from Cyprus. Already at this point we observe a
striking contrast in quality with copper from other
periods and other localities. At Oman, during the first
half of the third millennium B.C.E., copper with a
very low porous volume was produced from sulfate
copper ores and was melted to bun-shaped ingots
(Hauptmann 1985: 81, fig. 63; 1987: 210). This was
the traditional bulk metal traded in the Bronze Age
in the Persian Gulf area. Raw copper and ingots produced for export—e.g., from Timna, Israel (Roman
1990), and Feinan, Jordan (unpublished results Bo-chum)—reveal an excellent density compared with
those from Uluburun or Cyprus, respectively. This is
certainly due to the oxidic nature of the ores which
prevents unwanted degassing of sulfide inclusions
from ores such as chalcopyrite. However, as exemplified by bar ingots from the end of an Early Bronze
Age (ca. 2300B.C.E.) metal factory at Khirbet Hamra
Ifdan, Feinan (see also Levy et al. 2002), the high
quality of the copper is due not only to the nature of
the ores, but to improvements effected by repeated
remelting of lumps of raw copper into batches large
enough to cast an ingot of 250–300 g.
Already in this first section we can see that Wakefield has a poor understanding of what quotation marks mean and how to use them in an article. You'll also note that he conveniently forgot to quote the bit comparing the porosity to ingots from Cyprus.
From pages 6-7:
Quote
All ingots contain angular-shaped inclusions of iron-silicate slags that may
reach a size of up to 5 mm in diameter (figs. 2, 4–
5). They consist mainly of an olivine with a composition close to fayalite (Fe2SiO4) and magnetite
(Fe3O4); occasionally we identified copper sulfides
(chalcocite, nearly Cu2S) or mixed copper-iron
sulfides (nearly chalcopyrite, CuFeS2). There are
striking similarities to slag inclusions described by
Zwicker, Virdis, and Ceruti (1980) from copper oxhide ingots from Sardinia. Our slag inclusions show
typical structures of cooling from a liquid—i.e., lath-or needle-like skeletons of olivine and dendrites
of magnetite (fig. 7)—to be expected from slags
tapped from a furnace. In parts, however, they contain a mineralogical phase with the name iscorite
(Fe7SiO10), which is typical for reheating iron silicates. In addition, they exhibit features comparable
with natural rocks that were affected by contact-metamorphosis, i.e., an impact of high temperatures
in the solid state. Here we observe a granoblastic
structure with isometric mineral grains caused by a
recrystallization due to reheating. Those slag inclusions show coronas of iron oxides formed by oxidation of iron silicate slags at high temperatures. It
is obvious that the copper used to cast these ingots
has characteristics of raw copper produced by a primary smelting process and was not completely separated from adhering slag. There was apparently no
interest in a thorough purification of the metal to
remove these slag inclusions. This suggestion is
supported by both the archaeological and the experimental evidence which indicates that a complete
separation of slag to remove a piece of clean copper
seems to have been not easily understood in ancient
metallurgy. Striking examples are given by Bamberger and Wincierz (1990: 134, fig. 132). The metal
produced by experimental smelting is covered by a
thin layer of slag. The same is true for a piece of
copper from Beer Ora, Timna (Tylecote and Bachmann 1990: 76, fig. 105) that is covered by slag.
Also at Feinan, lumps of copper found at smelting
sites usually show adhering remains of slag (unpublished results Bochum). As observed by Bisson
(2000: 141–43) from an ethnoarchaeological context in Africa, such adhering slag crusts have to be
removed by hammering the lumps produced by
smelting, and by repeated melting processes in order
to obtain high-quality metal. The author points out
that these were regular steps in copper production he
observed at many metallurgical sites all over the
middle and southern part of Africa. Obviously, the
Uluburun oxhide and bun-shaped ingots were not
processed in such a way.
So we see here the same poor quoting and that he ignores all the evidence presented of inclusions coming from the smelting of ores to get the copper.
From page 17 (he really jumps around a lot in constructing his "quotations" from this paper):
Quote
Evidence in support of Tylecote’s hypothesis is
the existence of slag inclusions in both types of
ingots. Their composition is characteristic of slags
from smelting copper ores under reducing conditions, but not of those from crucible (s)melting. We
could demonstrate that the iron content of the ingots is primarily due to these slag inclusions and
does not permit conclusions regarding the use of
iron-rich fluxes. The angular shape of slag inclusions, the structure, and the existence of iscorite
hence point to a pouring of copper into a mold
when the slag was already solidified and before it
was melted again in the crucible. This excludes casting directly from a smelting furnace: the slag would
have left the furnace in the liquid state and would
be included in the copper as globules. It also excludes an origin, or a solidification, respectively, of
bun-shaped ingots on the bottom of a smelting furnace. Such inclusions of globular slag, for instance,
were observed by Craddock and Meeks (1987) in
the (so-called) ramo secco bars from Roman Italy.
The angular shape indicates that the slag, or the copper, had been mechanically treated. Such a process
is fairly underestimated and neglected in the literature, but is evidenced by archaeological findings
from Iron Age copper production at Feinan (Haupt-mann 2000) and from the Late Bronze Age copper
production all over the Alps (Hohlmann, Hauptmann,
and Schröder in press), and by ethnoarchaeological
research (Bisson 2000: 141–43): that is, the slag
was crushed after smelting to recover copper lumps
and prills or copper matte, and to separate adhering
slag.
He again conveniently plucks a quote right out a context explaining how the copper was smelted.
From page 9:
Quote
Fig. 6. Sample KW 3421. Porous volume of a bun-shaped ingot caused by interdendritic shrinkage and gas bubbles. Note several interfaces of dense metal which point to different batches during casting.
From pages 7, 8, and 12:
Quote
Cuprite Inclusions.
Almost all copper samples
investigated contain cuprite (Cu2O) distributed in
changing amounts throughout the ingots. It occurs
in two different textures that allow us to distinguish
its conditions of formation. Of subordinated interest
for our investigation is the formation of cuprite by
corrosion processes that represent the weathering of
the ingots in the sea since the ship sank in the Late
Bronze Age. Cuprite of this origin shows layers and
protrusions (fig. 8), in some cases small crystals
preferentially formed at the surfaces or in the pores
of the ingots. The corrosion does not penetrate the
copper ingots for more than 5 mm or so, and in
every case they are much less affected than the tin
ingots. This is a conservator’s problem, but it does
not provide any information about the pyrotechno-
logical processes by which the ingots were formed.
Most characteristic, and visible in almost every
specimen, are copper–cuprite intergrowths that re-
sult from the nearly complete immiscibility of oxy-
gen in copper both in the liquid and in the solid
states. This is exemplifed by varying amounts of
cuprite inclusions in copper. If oxygen is low, cuprite
globules are formed like pearls on a string along
grain boundaries (fig. 9). The eutectic intergrowth
(fog. 10) indicates an oxygen concentration of 0.39
wt.%. These structures are formed during solidifcation at 1065 C, slightly below the melting point of
copper itself. They are visible throughout the ingots
and are associated with large voids. A considerable
surplus of oxygen in the gaseous atmosphere of the
reaction vessel caused further oxidation of the copper far above the eutectic (> 0.39 wt.% oxygen) and
led to extensive precipitation of lumps and larger,
equiaxed crystals of cuprite (hypereutectic composition; fig. 11). In parts, they are embedded like a dispersion in the copper matrix (fig. 12) with beginning
dendritic crystallization. Often these crystals show
breakage due to deformation during and/or after
solidi˜cation. These oxide particles, of course, affect
the malleability of the copper and make it brittle.
Relatively pure copper today—for example, electrolytic copper, 99+ wt.% pure—may contain no more
than 0.02–0.07 wt.% oxygen. If the copper is heated
in a reducing atmosphere to temperatures above
about 370 C, the oxygen concentrations can be
diminished, but the copper is subject to embrittlement. If hydrogen or carbon monoxide is present,
the embrittlement may be rapid (Tyler and Black
1990).
A gas atmosphere necessary to produce cuprite
in an amount observed in our samples does not prevail during the smelting of (roasted) ores. This must
be conditioned toward the reduction to metal in (at
least partial) equilibrium with a fayalite slag (fig. 13)
(Eugster and Wones 1962; Abs-Wurmbach et al.
1983). It would exclude the formation of cuprite. We
therefore can eliminate the conclusion that the ingots consist of as-smelted raw copper tapped directly
from a smelting furnace (contra Tylecote 1976). Our
explanation is that the copper, before being cast into
oxhide or bun-shaped ingots, underwent a subsequent remelting process in a smaller reaction vessel,
perhaps in a crucible which led to the precipitation
of cuprite. This seems to have been a widely distrib-
uted phenomenon, as Cooke and Nielsen (1978) and
Zwicker (1984) demonstrated by investigations on
archaeometallurgical finds from casting workshops
at Nichoria (Late Helladic period) and Olympia (fifth
centuryB.C.E.). The slag inclusions observed can
easily be interpreted as relics from a primary smelting process that were not removed. Their granoblastic structure and oxidation coronas are in accord with
a reheating during remelting.
So you can see here the same manipulation of quotes as elsewhere. In particular if you look at the last emphasized part, you'll note he actually drops two words from the sentence that completely changes its meaning. Yet again, though, the actual report of Hauptmann et al. is that this is copper smelted from ores.
I'll stop the quote play here as I've reconstructed most of the two paragraphs of Wakefield, and I think I've demonstrated clearly that he's blatantly manipulating the report to suit his argument when in fact the report goes against him. If you continue to read the Hauptmann et al. article, though, you'll find plenty of other contradictory information. For example, they note that the composition of the ingots is only about 99% copper on average (p. 13)--a far cry from the 99.92% purity Wakefield quotes for native copper (on page 3 of his article). They also note that much of this impurity came from the slag that resulted from the process of smelting ore (p. 13), and that such impure copper would have needed significantly more purification before a smith could use it (p. 18). And they also note that their results fit with the hypothesis that this copper came from Cyprus (p. 15).
So clearly Wakefield's article is without merit. Moreover, it's clear that he read the Hauptmann et al. article and deliberately manipulated it to support a point opposite to the conclusions of the article--that is, he knowing lies. He is consciously spreading misinformation. He is not simply a confused, well-intentioned researcher, but rather a deliberate deceiver.
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