Dust flux, Vostok ice core

Dust flux, Vostok ice core
Two dimensional phase space reconstruction of dust flux from the Vostok core over the period 186-4 ka using the time derivative method. Dust flux on the x-axis, rate of change is on the y-axis. From Gipp (2001).

Thursday, August 5, 2010

A partial history of hard money in Ghana

When you travel through Ghana, one feature that leaps out at you is the pile of concrete (actually sandcrete) blocks piled up on people's property. It is not unusual to see them in a place where construction is obviously ongoing, but what seems strange is seeing such piles of blocks in front of  houses in which the signs of new work are absent. Or as you whip along the highway you encounter plots of vacant land dotted with a couple of small piles totalling perhaps twoscore blocks. What's going on?

Block plant at Weija, just west of Accra. Block plants are everywhere in Ghana.

Here's the thing. About 40 years ago the Ghanaian unit of currency, the cedi, was equal in value to the US dollar. So if your uncle had been a millionaire in those days, and hid his money in the basement and then forgot about it, what would it be worth now? Brace yourselves--that million cedis you just exhumed from his basement was converted in July of 2007 into new cedis (called formally the "Ghana cedi") at a rate of 10,000:1. So if you went to the bank with one million old cedis, you would receive 100 Ghana cedis, which would be worth about USD 70. That is some loss of purchasing power, even if you ignore what has happened to the US dollar over the same timeframe.

If your uncle had been smart enough to buy gold, he would have been well ahead of the game, but even though Ghana is one of the top gold producers in the world, it was facing hard times in 1970 and there wouldn't have been a lot of gold around. Probably the best he could have done would have been to have stored his wealth in pessawa coins (1/100 of a cedi, and made of copper in those days). One hundred million such coins, although bulky, would have done a much better job of preserving his wealth than paper.

Given their monetary history, Ghanaians seem to well understand the futility of storing wealth as paper. The gradual decline of purchasing power of the new cedi (which was worth more than 1 USD in July of 2007 but is now more than 30% less) provides constant reinforcement of that basic lesson.

So how do you preserve your wealth in a persistently inflationary environment. You invest in hard assets. While for most of us that means gold, in Ghana it now means sandcrete block. They don't rot. They tend not to go away. They tend to hold their value (their price rises roughly at the same rate as the value of the cedi sinks). They are useful--most of their buyers actually intend to build something, but lack the capital to build it all at once. As there are no other useful ways to save, they hold their savings in the form of block. If they accumulate enough block they can build a better house.

The use of block as a hard asset is a relatively recent economic innovation, and has been responsible for a rapid profusion of block plants over the past ten years. This in turn has led to something of a boom in residential and small commercial construction. But different assets have been used in the past.

Gold and cowries

Ghana is the former Gold Coast. And the history of gold in Ghana is a complex one.

Gold ornaments and jewellry from West Africa have long been known to the outside world. For centuries, worked gold was sent north across the Sahara, to North Africa and Egypt (Garrard, 1989). The gold was supplied from a series of West African kingdoms, including Mali, the Songhai, and ancient Ghana (Bovill, 1995). As far as modern Ghana is concerned, the most important gold trade involved the Asante, a kingdom which arose and came to prominence due to improved agricultural practice (Wilks, 1993), but which is best known for the quality of its goldsmiths (Ayensu, 1997). The Ashanti carried out trade for gold with both Moors and Europeans, but most quantitative estimates of gold traded come from the European trade.

European exploration of West Africa was driven by a number of factors, including population pressure and the desire for new wealth. It was facilitated by the improvement in navigational aids (compass, astrolabe, quadrant), in ship design (mating of square-rigged sails and rudder from North Sea vessels with Mediterranean carvel hulls), in chart designs (Mercator), chart construction, and printing.  But the major impetus was the establishment of a navigational centre in Portugal by Prince Henry, which lasted from 1418 until his death in 1460 (Guill, 1980). The Portuguese took slaves at Arguin, an island in a bay (which may have been Cerne) that they fortified in 1448 to serve as a trading centre.  Alvise da Cadamosto discovered the Cape Verde Islands in 1457, and reached what is now Guinea-Bissau. By 1462, Portuguese ships had reached what is now Sierra Leone.

By this time, Cadamosto had determined that the gold coinage of southern Europe dating from the 14th and 15th centuries had its origin in West Africa.  He determined that it had come from the Gold Coast and the upper parts of the Niger, Senegal, and Gambia rivers, from which it passed through Melli and Timbuctoo, then overland to Tunis, Algeria, and Morocco (Junner, 1973).

From the Moors of northern Morocco, the Portuguese learned of the gold in the Gold Coast, and in 1471, led by Moors captured in Senegal, two Portuguese ships under the command of Juan de Santerem and Pedro de Escobar reached the Gold Coast, where they immediately began trading in gold dust. The trade was set up at a place called by the Portuguese “Oro de la Mina”, and this was initially held to be Elmina, although Kesse (1985) contends that it was Shama, near the mouth of the Pra River.  Fernão Gomes established a trading centre at what is now Elmina, and its importance was so great that a large fort was built (São Jorge da Mina) in 1481.  In 1482, Diego Cam reached the Congo River.  The map of Martin Behaim (1492) clearly depicts São Jorge da Mina to the east of Cape Three Points, as well as the Pra and Ankobra Rivers (Emery and Uchupi, 1984).

Old map of the Gold Coast (present-day Ghana). Compiled by Boulton (1787).

The first trade in gold dust from the mouth of the Pra River by the Portuguese is the first well-documented record of gold being obtained from the Gold Coast (Junner, 1973), although there is abundant evidence of earlier trade.  When the Portuguese arrived in the Gold Coast, the natives were predominantly hunters and fishermen.

The chief wore a great deal of gold, but gold was not used as money. Trade was conducted by the use of goods and cowrie shells.  Cowrie shells were directly convertible into gold, at the rate of 32,000 cowries to one ounce of gold (Anin, 1994).  Forty cowry shells would be tied into one string, five strings made one bunch, and ten bunches were equivalent to one Ackie of gold.  The Ashanti had a very involved system of gold weights and standards, whereby there were 16 Ackies in one ounce of gold and, 12 takus in one Ackie (Niangoran-Bouah, 1977). In the interior, gold was used as currency, according to Leo Africanus (1526), but shells imported from Persia were used for small matters.

So we see that one day, some strange-looking people showed up and began to offer fantastic items like umbrellas and steel pots and firearms and alcohol for this worthless stuff that any fool could find in any amount desired in just about any river. The sudden appearance of all this alien technology had a profound impact on the peoples on the Gold Coast, mainly causing them to re-evaluate their perception of the value of gold.

This is trade at its best. Two groups meet, each holding something that has little value to them, yet they are able to trade it for something of tremendous value. If only the interaction between Africa and Europe had remained limited to this trade.

Until the 16th century, the natives possessed considerable quantities of gold, which they had undoubtedly accumulated over a long period of time. They placed very little value on it, using it for ornamentation, and to sprinkle on the bodies of the dead (Anin, 1994). Gold was buried with the dead, because it was thought that they would reappear in a world where it would be of great value. It was freely traded for things of little value to Europeans. The natives were well accustomed to winning gold from stream and beach gravels, and they did not begin attempting to mine auriferous reefs until the early 18th century.

 Woodcut from Dapper (1668) showing native gold mining in the lower Ankobra River (presently in the western region of Ghana). This image was taken from Garrard (1989). If you visit the lower Ankobra you will notice that this image is reversed--it is unclear whether this is due to the image being the reverse of the woodcut, or whether the print was somehow reversed before appearing in Garrard (1989).

 Olfert Dapper (1668) described how the natives of the lower Ankobra River would dive into the river, returning to the surface with nuggets from the river gravels. John Bardot (1732) furthered this description, adding that the natives would return to the bank, with the bowl again on their heads, now filled with a mixture of materials from the riverbed, which were poured into bowls held by other men and women. These bowls were held against the flow of the river until the soils and sands are washed away, the gold sinking by its own weight to the bottom.  The gold has been described as being composed of small grains, but some in lumps as big as peas or beans, and as fine dust.

According to Bosman (1698), women and boys living near Elmina collected and washed beach gravels and sand after violent rain, using large troughs or trays, which they filled with sands and washed out the lighter material with water (between Elmina and Apollonia). The concentrate was washed again in a small tray until the gold could be removed. The process is much the same today.

Galamsay (artisanal) miners in action north of Asanta (just west of the Ankobra River) in early 1997. This property is now part of Adamus Resources Limited's Nzema Gold Project.

Descriptions of native women recovering gold near Cape Coast in the early 19th century suggest that they repeatedly washed the sands in a circular fashion in large wooden bowls, and visually inspect for gold at the bottom. Any gold found was dried in the sun or by fire. In the area around Taccorary (Takoradi), the natives had many rich mines where they dug ore and ground it between rubbing stones to separate the gold from the quartz.

Knowledge of gold production from the Gold Coast is sketchy.  Annual production fluctuated considerably, especially during slave wars, but estimates of production up to 1930 exceed 22 million ounces (Junner, 1973).  Production in the late 1860’s was probably less than half what it was in the early 1800’s.  Production fluctuated between about 10,000 and 20,000 ounces per year until 1903, when production climbed sharply to 200,000 ounces per year (by 1906) as European-operated mines came into production.
Artisanal mining (galamsay) activity is still very common in southwestern Ghana. Old galamsay workings are evident at numerous places along the coast. 

Money of stone

There have been other forms of money used in the Gold Coast as well. Junner (1973) refers to an early encounter with natives in what is now western Ghana who used "ceremonial axes" as money. When I first read this description, now over fifteen years ago, my first thought was "how did they know they were ceremonial?"

As you enter the Western Region of Ghana, you enter the region of Cape Three Points. This is the most prominent feature in the above map of the Gold Coast--the southernmost tip. The Ankobra River is near the western boundary of the map. A short distance west of the point--perhaps fifteen kilometres west of Cape Three Points--lies Aketekyi and Princes Town. Princes Town is the site of an old German castle (of which more will be written some other time).

I was working on the headland overlooking these two towns in early 1997 with a venerable geologist. We were walking at the edge of a cornfield on or very near the highest point of the headland--we could see the embayments on both sides of us--when my companion suddenly asked me to stop and look around. I did not notice anything out of the ordinary. He asked me what I thought about all the flakes of stone lying around on the ground. Well, okay, I could see they didn't come from the local rocks because there were none. And no boulders either. He picked up one angular piece of stone and opined that it was a hand axe. A hand axe that had broken while being flaked and so it was discarded.

I was completely skeptical. I had to admit that he had had past experience with stone age tools, having seen them during previous fieldwork in Europe. And I had to agree that the flakes of stone were definitely unusual. But I had a killer argument. The stone was talc! Talc is the softest mineral known. If you tried to cut a green sapling with a talc axe, all you would do is spoil the axe. Talc cannot cut wood--it cannot even whittle wood. You can easily scratch it with your fingernails. So we had a brief argument about it and even though I could think of no natural process that would bring flakes of talc from an unknown location to the highest point for miles, I also did not accept that any group of people would be foolish enough to make axes out of talc. For that reason, sorry, I didn't take any pictures (this was before the digital age, at least for me).

As so often happens, the revelation came later. How did the first Europeans know the natives' axes were ceremonial? I had assumed when I read those words that the axes were very small. But what if they were made of talc--a material that is too soft to be useful as a tool, but is fairly easy to work (not withstanding the occasional accidents that result in spoiling the labour).

About two years ago I decided to try to retrace my steps. My guide Kabi and I drove back to Aketekyi and quickly ascended the ridge to the headland. We were close to the stone flaking site when we were blocked by a local land-clearing project.

Fires on the Aketekyi headland, September 2008.

We were forced to retreat, and I made a fortunate discovery. I noticed the path we had retreated along looked a little bit chalky. Following the lumps of "chalk" back into the woods led me to a small defile crossed by the path, and in the exposed rock was a thin seam of talc schist. Interestingly, there were telltale signs that the little seam had been mined some time . . .

Outcropping talc schist on the Aketekyi headland. The talc is the angular pebbles in the shade of the tree.

Which begs the question--how would stone axes work as currency? I think the way they would work is that the value represented by the stone axe is the labour it took to make it. The number of axes in circulation could be increased only by applying labour, and as much of this labour would be needed for the day-to-day struggles of fishing and farming, there was probably not a great excess of labour available to make them. It is also possible that there may have been some kind of tribal restriction on the number that could be made, or some sort of guarantee like they had to be made by a particular artisan and had to be carved at a particular location, which may have had religious significance (or maybe they liked the view).

The valuation of worked stone as currency was not unique to coastal Ghana. Famously, the people of Yap used large stone disks as currency, the labour value of which was considerable as they had to travel to distant islands to obtain the stone.

One mystery may be solved, but that brings me to another. The streets of Axim (a coastal city near the Ankobra River) are covered with gravel. According to local lore, much of this gravel was dredged up from the sea, primarily by dragline, although no one seems to be able to put an exact date on when this happened. Among the stones of some parts of Axim are these.

Stones of Axim, with holes of uncertain origin.

My first thought, when finding these, was that they were fire-starter stones--the holes worn into them by the friction of the spinning wood. But it doesn't seem logical to use such small stones for such a purpose. Also, the two holes on the right side of the rock at the top of the picture above are actually one "U-shaped" hole. This would seem to be very difficult to make accidentally, and might preclude a natural origin (given the hardness of the rock).

There are organisms which can make indentations in a rock. Abalone, for instance do this, and there are rocks along the shore not far from Axim which have just such marks in them.

The indentations on the rock at left are caused by abalone, but they are all much larger than the indentations in the above pebbles. Note the linear distribution--the abalone seize on planar weaknesses in the rock, where it is easier to rasp their way in.

Furthermore, some of the indentations in the pebbles actually pass completely through the stone (below).

So far we have only found these features in dredged gravels of Axim, which does happen to be one area with a profusion of tool-sharpening marks on coastal rocks.  Assuming they are man-made and not some natural features, they do not appear to be useful items, nor do they appear to be representative of anything. They may have been some simple ornamentation.

Or maybe they were money. Once again, the value of the individual pieces could have been tied to the labour represented by their fashioning. I have no evidence that these were money, but there are a lot of them to be found in shallow marine gravels in western Ghana, once again pointing to the possibility of finding evidence of human habitation in what is now the sea.

Ghanaians have come full circle--from using worked stones (possibly) as money, to worked stone axes, to cowrie shells and gold, and back to worked stone (sandcrete block). I don't see any signs of paper money used except in the very recent past.

Additional note: The sandcrete block is a useful hedge against inflation. But it is a poor hedge against deflation, which sadly, occurs with a vengeance every five years or so. Paper money vanishes, and people with block find they can trade them for neither money nor food.


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Ayensu, 1997. Ashanti Gold: The African Legacy of the World's Most Precious Metal. Marshall Editions, 200 p.
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