Dr Camillo Premoli - International Mineral Resources - Consultants - 1996

 

GOLD IN MADAGASCAR

Dr Simon McDonald has purchased Camillo's extensive files and map collection, including a comprehensive data set for Madagascar. E-MAIL LINK

 

I.  SUMMARY

 

1.1

 

Very little is known about the potential gold deposits in Madagascar, but the country's estimated gold production is far from negligible. It runs to approximately 3-4 t/y and "could easily be doubled" (Mining Annual Review - 1995, p 149).

 

This is a large amount considering that all of it presently comes from "artisan" mining - or very

small syndicates - and mining is largely alluvial. Estimates of Madagascar's total gold

production since it began late last century is a highly respectable 70 tonnes.

 

 

1.2.

 

Madagascar's primary gold deposits are thought to be of mesothermal "lode" quartz-hosted type,

and they are hosted in Proterozoic or, more frequently, Archean terrains. Lode gold deposits of

this type account for nearly 20% of world deposits, and are largely responsible for the vigorous

gold development of Australia, Canada, Brazil and Ghana.

 

There is no evidence in Madagascar of sediment-hosted gold deposits, pebble-conglomerate

deposits, gold-rich porphyry copper deposits or epithermal gold deposits. Although their presence

cannot be excluded given the current level of knowledge, their occurrence seems unlikely.  

 

 

1.3.

 

Madagascar's geological records are far more difficult to access than is usual with African

countries. This is particularly galling as, until 30 years ago, Madagascar was one of the best

geologically studied countries in Africa, with several thousand first-class records.

 

Unfortunately, virtually all these records are in French and it is  very difficult to gain access

to them (Ph.D theses, obscure records buried in the archives of poorly organised institutions,

etc.). There is no evidence to suggest that this situation will change in the near future.

 

 

1.4.

 

Like many other countries in Africa, Madagascar flirted for almost two decades with

socialist-inspired, centrally planned economic policies and this ended only very recently with

the demise of Soviet communism.

 

The country's economy suffered grievously from these policies. A more sober political line was

re-established in 1993 with a return to a form of liberal democracy.

 

 

1.5.

 

French influence in all Francophone Africa, and Madagascar in particular, continued long after

the country's formal decolonisation in the early '60s. Indeed, it has only been in recent years

that France made clear that her interest in French-speaking Africa was decreasing. This process

started even before the devaluation and floating of currencies in ex-French African countries

(including the Malagasy Franc) in May 1994.

 

This long-overdue decision greatly boosted indigenous production, particularly agriculture, and

discouraged imports, particularly from France, which were directed essentially to an African

urban elite.

 

Until 1995, African politicians gave financial support to various French political parties. The

courtesy was reciprocated by very flexible bilateral co-operation agreements, which involved

Madagascar.

 

1.6.

 

The three factors mentioned above - stagnant economies, renunciation of socialism, and a lessened

French influence - have created new opportunities in Francophone Africa, particularly in mining.

This point has not been lost on the international community in west Africa, and IMR suggests that

this perception could be extended to Madagascar.

 

A significant gold producer now and in the past, Madagascar is about the size of Spain (or 41% of

South Africa), and contains prime Archean-Proterozoic terrains beneath its surface. The country

remains one of the best gold exploration targets in Africa.

 

 

1.7.

 

However, French cultural heritage is well rooted in Madagascar, and perhaps rightly so. Most

Frenchmen had a special affinity with and liking of Madagascar, a fully independent and

functional country long before colonisation.

 

The grotesque "technicians" from North Korea that arrived in the '70s were received with mild

incredulity by a sophisticated Malagasy society. Although very poor, Madagascar never seriously

knew the cultural soul-searching of, say, Zaire or Ethiopia. The country remains to this day a

unique Malagasy (not African) state, with an overlay of French language, French background and

French culture. Any bullying will be resented. Overseas investors should take warning.  

 

 

1.8.

 

The present report aims to consolidate all available "open file" information on gold in

Madagascar. The information is presented in a modern and, wherever necessary, interpretative way,

and it is directed to major investors. For easy consultation, part of the material has been

presented in computer-generated databases that can easily be down-loaded in the reader's

computer system and edited or increased at will.

 


2.  INTRODUCTION

 

Several factors have radically affected Madagascar in the past few years. Among these have been:

 

- The collapse of Soviet-type economies in the period 1989-1992.

 

- South African renunciation of Apartheid politics, and its opening up to democracy and trade,

particularly with southern African countries.

 

- Madagascar's adoption, on August 19, 1992, of a new constitution with a bicameral legislature,

a National Assembly elected by universal suffrage, and a president as constitutional Head of

State elected for a term of five years. The first elected president, Professor A. Zafy, was

inaugurated in 1993.

 

- The renunciation by France in May 1994 of its policy to keep the Malagasy currency artificially

pegged to the French franc.

 

All these circumstances, coupled by a sustained gold price, has created a situation in which gold

exploration in a newly democratic country of great geological potential - such as Madagascar -

suddenly makes sense.

 

The present Database is intended to fill a void of relevant information about Madagascar. Its

objective is to present in a modern way what is known about gold in Madagascar from open-file

sources. Regrettably, some of these sources are no long available in Madagascar itself.

 

As the great majority of the potential mining investors are English speaking this is the language

which has been chosen for the Database.

 

The report is based on modern compilation methods. We have sought to use French reporting customs

in a way that Anglo-Saxon readers will understand. We liberally used computer techniques such a

tabulations, cross-indexing etc to provide the reader with immediately accessible information;

actually we feel that this has been the most valuable side of our work: to present in a

state-of-the-art framework information that can only be laboriously gathered in dusty files in

Europe or Antananarivo.

 


3.  SCOPE OF THE DATABASE

 

No-one has seriously explored for gold in Madagascar for nearly 50 years. Although gold has been

mined in the country for more than a century, comparatively little is known about its objective

potential. For this reason, Madagascar's gold resources fall - by western standards - into the

"hypothetical" or "speculative" categories, not "proved" or "possible" reserves.

 

Gold exploration in Madagascar, particularly in the initial stage, would be quite risky, and the

crucial early phase of collating all the existing data would be very time-consuming, particularly

for non-French investors. But these are precisely the investors presently sought after by the

Malagasy authorities, understandably keen to enlarge their base of trading partners.

 

Madagascar's authorities are well aware of their island's gold potential, which is presently the

country's largest mineral export - albeit still clandestine and poorly regulated. The authorities

are keen to attract major gold explorers, within a legal and fair framework.

 

 

4.  METHODS USED

 

    4.1. Sources

 

The information on Madagascar's gold potential is rather dispersed. The main sources of

information for the present Database have been:

 

1) A computerised search on Madagascar's geology and metallogeny, utilising any CD-ROM geological

database available in 1995;

 

2) Previous reports by IMR staff who had worked in Madagascar;

 

3) A detailed field visit to Madagascar in 1995;

 

4) Verbal communication in Madagascar or France with personnel personally involved in gold

exploration in Madagascar;

 

5) Rapid examination of some satellite images of the country;

 

6) Study of various geological maps of Madagascar. The six sheets at 1:500,000 (1971) and the

three sheets at 1:1,000,000 (1964) have been particularly useful as most major gold occurrences

are recorded;

 

7) Articles and papers from professional journals and publications, not only on Madagascar but on

its geological neighbours, including Tanzania, Mozambique, India, Sri Lanka and Antarctica.

 

As the senior author of the present report spent two years in Madagascar in the 1970s, and has

made numerous visits since that time, the material above has been supplemented with personal

information and opinions.

 

In presenting the information care has been taken to distinguish factual information from IMR's

personal opinions and considerations. A clear distinction between "matter of fact" and "matter of

opinion" has been maintained throughout the Database. 

 

The name of 216 recorded Malagasy gold prospects is given in three different databases ordered by

name, gold district and genetic type (Tables 5,6 and 7). The geographic position of at least 130

gold prospects and gold districts is given in illustrative sketches (sketches 7/2 through 7/12).

 

Madagascar's old French geographical names have now been changed to Malagasy ones (Fort Dauphin =

Tƒlanaro, etc.). This can be slightly confusing, particularly when old documents or maps are

consulted. The new "Malagasy" spelling of localities has been maintained throughout the Database.

 

In addition, until very recently the geographic co-ordinates in Madagascar were given using the

"Laborde" co-ordinates system (see sketch 5.2.1). "Laborde" co-ordinates can be converted through

a conveniently programmed Geographical Information System in any other modern co-ordinate system.

 

As technical French (or French/Malagasy) terms used in gold mining are not generally given in

normal English-French dictionaries, a brief glossary of these terms has been included in the

Database (Table 8a-8b). Its purpose is to allow people with even a very rudimentary knowledge of

French, or those using non-specialist interpreters, to be able to communicate on the subjects of

this Database.
5.  GEOGRAPHICAL AND SOCIAL FRAMEWORK

 

    5.1 Physical and social geography - General

     

The Democratic Republic of Madagascar (Madagascar throughout this report) comprises the Island of

Madagascar, the world's fourth largest island, and several much smaller off-shore islands.

 

Madagascar lies about 400 km from the African mainland across the Mozambique channel. In reality

Madagascar is not part of Africa proper but a micro-continent of its own, stranded between Africa

and Southern Asia. This is apparent not only by its population but also by its unique fauna and

flora.

 

Madagascar extends 1,600 km from north to south and it is about 500 km wide. It covers an area of

587,000 km2, or slightly more than France and Belgium combined. Geologically, Madagascar is

composed essentially of crystalline rock, which forms the central highlands that rise abruptly

from the wide plains of the west coast. Once again, Madagascar's mineral provinces present

several similarities with S.E. Asian ones, particularly India and Sri Lanka.  

 

 

    5.1.1.  History

 

It has been said that large islands (U.K., Japan, Cuba, etc) have a tendency to have "different"

behaviour. If that is true, Madagascar is no exception.

 

Madagascar was the only African country - with the dubious exception of Ethiopia - that was

independent long before colonial times. By the end of last century Madagascar had developed a

truly unified government, supported by a regular standing army, a crude but effective judicial

system, education, public works, administration and the like. The stone palace of the last

Madagascan queen (Ranavalona III) still proudly overlooks Antananarivo.

 

In a way, Madagascar was more Asian than a typical African country; a distinction that survives

to this day. During the "scramble for Africa", France, excluded from East Africa after the famous

"Fashoda" incident in Sudan, thought Madagascar an attractive prize. Its strategic position in

the Indian Ocean, its perceived richness in mineral resources (and particularly coal - then a

vital commodity for any major fleet) played an important part in this decision.

 

Madagascar was invaded by France in 1895 and become a French colony one year after. The country

was entirely subdued only 10 years later. 

 

Colonisation followed a typical pattern: appropriation of land by French settlers and companies,

the exploitation of the peasantry through forced labour (although this practice predates French

arrival), the imposition of an import-export economy - essentially based on coffee and vanilla -

with the construction of roads and railroads to serve it. Gold exploitation at the beginning of

the French colonisation had a profound effect on what was up to then a near cashless society,

based on subsistence farming and barter.

 

Autocratic and alien as any colonial regime invariably is, there were positive aspects of French

rule on the island: hospitals were built, a very effective administration was put in place and a

Malagasy elite was trained to French intellectual standards. It is also fair to say that the

French colonial administration was better than those of Portugal, Germany or Italy on the other

side of the Mozambique channels, and more enlightened than the Belgians in the Congo.

 

Many Frenchmen took a sincere liking to Madagascar and some never returned to France (among them

H. Besairie, the father of Malagasy geology). Mixed marriages were common. France always referred

to its overseas African colonies as "Territoires d'Afrique et du Madagascar", stressing the

individuality of the latter. A nice and appreciated touch.

 

Malagasy units fighted with distinction in World War I.

 

It was during World War II that Madagascan history took a bizarre, and little known, turn. After

France was overrun by Germany in 1940, Hitler toyed with the idea of shipping the several million

undesirable European Jews to Madagascar (Gilbert, 1989 p.323) - a blander sort of "final

solution". A strongly anti-Semitic Vichy government showed an immediate and keen interest in the

project, but neither the French nor the Germans had adequate ships or enough control of the sea

to implement this odd scheme.

 

Throughout World War II, Madagascar - the "pearl" of the French colonial empire - was staunchly

pro-Axis and pro-Vichy.

 

After the fall of Singapore, a slightly paranoid British high command saw Madagascar as being the

next stepping-stone of Japan's expanding empire. On May 9, 1942, a British contingent landed in

the port of Diego Suarez (now Antiranana) under heavy French fire. On May 31, Japanese midget

submarines on a suicide mission sank a British merchant ship and damaged a battleship in Diego

Garcia (Gilbert, 1989, p.330).

 

It took weeks for the British forces - with many casualties - to fight every inch of the way to

reach Antananarivo and put Madagascar under the "Free France" of De Gaulle's rule.

 

At the end of WW2 a strong pro-independence movement took root in Madagascar. Open hostilities

erupted in 1947. But most of Madagascar's topography is unsuitable for guerrilla warfare and,

contrary to Vietnam or Algeria, Madagascar had no sympathetic bordering countries. The rising was

quashed with much bloodshed - more than 80,000 Malagasy casualties.

 

In 1956 the French "loi cadre" instituted universal suffrage and transferred a significant share

of executive power to the Malagasy, essentially to the c“tier-dominated Parti Social D‚mocrate

(PSD).

 

But in was not until the 1960s that De Gaulle's France bowed to the inevitable and restored

Madagascar to full independence, although on terms very favourable to France.

 

Under the Malagasy Republic's first president, the "c“tier" Philibert Tsiranana, the French were

allowed to retain their hold over trade and financial institutions and keep their military bases

on the island. Tsiranana also maintained a dialogue with South Africa and refused contacts with

communist countries.

 

The increasingly unpopular Tsiranana was overthrown by a military coup in 1972 and this initiated

a fundamental change in Malagasy policy. Aid agreements with France were renegotiated, the French

military bases were closed down and so was an important NASA tracking station.

 

The economy saw a return to the collective work system that had been practised in the rural areas

before colonisation. The new government also severed diplomatic relations with South Africa,

Taiwan and Israel and formed new links with China, the USSR and especially with North Korea.

 

Several military men succeeded each other in rapid succession and eventually the government

stabilised under Lt-Commdr. Didier Ratsiraka, a "c“tier", in 1975. Banks were nationalised, and a

network of public corporations was set up to deal with the agricultural, marketing and even

mining sectors. The petroleum refinery and most mineral resources were nationalised. By and large

the new leftish tendencies of the Government resulted in costly failures exacerbated by the

1981-82 international debt crisis. 

 

By 1990 the Ratsiraka's regime, like most left-leaning regimes worldwide, was showing serious

signs of exhaustion and a lack of capacity to solve Madagascar's growing problems. An opposition

party, "Force Vives", took shape and a long political transition period started. Among other

measures the new Mining Code of August 1990 improved the terms for foreign investment.

 

A new constitution - endorsed by national referendum in August

1992 - was adopted. Legislative elections in June 1993 produced a majority in the Assembly for

the opposition party "Force Vives", which promptly elected a prime minister from its own ranks. A

President, Professor Albert Zafy, also from "Force Vives", was elected in a ballot between eight

candidates in February 1993. With two thirds of the vote he easily beat Ratsiraka, who gained

only 33%.

 

Although the problems affecting the Malagasy economy remain very serious, Madagascar's peaceful

transition from a military dictatorship to a parliamentary democracy bodes well for its future.

 

 

    5.1.2  Population and Culture

 

History and geography account for the diversity of Madagascar's population which was estimated at

13,100,000 in mid-1995. The population is increasing at a annual rate of 3.1%, fast outstripping

Madagascar's capacity to feed and employ them.

 

The majority of Madagascar's population descends from Malay and Indonesian migrants. They began

arriving in the 6th century when the powerful Hindu-Sumatran empire of Srivijaya controlled much

of the maritime trade in the Indian Ocean.

 

These people brought with them the food crops of South-East Asia, so that even today Madagascar's

agriculture resembles Asia more than Africa. These earlier colonists brought with them a strong

dislike and suspicion of India which persist to this day.

 

There are 18 principal ethnic groups on the island. Here below is their distribution (1974

figures):

 

                   Merina (Hova).............1,993,000

                   Betsimisaraka.............1,134,000

                   Betsileo....................920,600

                   Tsimihety...................558,100

                   Sakalava....................470,100

                   Antandroy...................412,500

                   Antaisaka...................406,500

 

The dominant ethnic groups, the Merina and the Betsileo, who inhabit the most densely populated

central provinces of Antananarivo and Fianarantsoa, are of Asian origin. In the coastal areas

live the tribes collectively called "c“tiers" of which the most numerous are the Betsimisaraka on

the east coast. These tribes are of African and Arab origin. There is a lingering mistrust

between "c“tiers" and Merina-Betsileo people, the old ruling class in pre-French Madagascar.

 

Population density ranges from more than 30 inhabitants per km2 on the fertile central highlands

(where all Madagascar's gold occurrences are) down to two per km2 on the largely sterile west

coast.

 

French nationals, many married to Malagasy, numbered less than 15,000 in 1986 and their number is

decreasing. A minor, but persistent, point of friction between Madagascar and France are some

minor islands in the Mozambique channel that are claimed by both France and, reasonably enough,

Madagascar.

 

A Chinese community, numbering about 10,000, is dispersed throughout the east-cost region, where

they are principally employed as grocers, small-scale bankers and traders. Also inhabiting the

coastal areas are 10,000 or so Indian nationals.

 

Indians are rather unpopular with the Malagasys because of their clannishness and their wealth,

acquired through control of the textile and jewellery trade and urban real estate. Both Indians

and Chinese are major players in the vigorous gold smuggling trade out of Madagascar (often

through Mauritius), which the Government is all but incapable of controlling.

 

More than 82% of the Malagasy still live in rural areas, but the towns are inevitably attracting

an ever-larger percentage of the fast-growing, under-employed rural population, thus seriously

aggravating socio-economic problems. Antananarivo the capital, far from being the gracious,

pleasant little city of the '70s, is now a sprawling city of more than 1,000,000 people, mostly

living in very poor conditions. The other six provincial capitals also continue to expand.

 

The universal languages of Madagascar are Malagasy and French (apart from the vernacular dialect

of any particular tribe), which are currently spoken by anybody who has attended primary school.

English is understood a little by the most educated levels of the population in the major cities,

but not at all in the countryside.

 

    5.1.3  Currency and Banking

 

The national currency is the Malagasy Franc (MG Fr). In December 1995 the exchange rate was as

follows:

 

               1 $US    = 4,499.80 MG Fr

               1 œStg   = 6,967.80 MG Fr

               1 DM     = 3,038.66 MG Fr

 

Since 1994 the Malagasy Franc has not been pegged to the French Franc.

 

Liberalisation of the banking sector has attracted foreign private banks to Madagascar. Banque

Nationale de Paris is the main shareholder, owning 55% of Banque Malgache de l'OcŠan Indien

(BMOI), which was officially opened in January 1990. Belgian and German banks own 20% of BMOI,

and 25% belongs to about 300 Malagasy shareholders.

 

In 1991 a public investment program (1991-1993), financed by the World Bank, IMF and other

international donors, was initiated. The program, which cost an estimated $US 1,000M, again

placed emphasis on the liberalisation of trade and domestic sector, the encouragement of foreign

and domestic investment, a reduction in the role of parastatal bodies, and increased producer

prices.

 

Following a prolonged general strike in the second half of 1991, however, the program was

deferred, pending the fulfillment of certain conditions, which included the transfer of a number

of parastatal organisations to the private sector and a reduction of public expenditure.

 

The general strike of 1991 resulted in severe deterioration of the financial sector, with a major

fall in tax revenue and a rise in the budgetary deficit. That is now around 5% of GDP.

 

As matter of priority the new democratically elected president, Prof A. Zafy, established an

economic and financial co-operation committee in 1993 to conduct negotiations with international

donors, and resumed an economic program in conjunction with the IMF. The adoption of a number of

development projects, which included plans to rehabilitate infrastructure (with the assistance of

the World Bank) was also envisaged.

 

 

    5.1.5 Climate

 

Madagascar's climate is temperate and rather pleasant; temperatures in Antananarivo are generally

between 8§ and 27§ C, with cooler, dryer weather between May and October. The coastal region is

tropical with an average daily temperature of 32§ C. The rainy season extends from November to

April in the highlands - average annual rainfall is 1,000 - 1,500mm - but is more prolonged on

the coast, where annual rainfall can reach 3,500mm.

 

Geological exploration can be carried out continuously throughout the year.

 

 

5.2. AVAILABLE DOCUMENTATION

 

Madagascar has fascinated a number of authors and researchers (and still does). This has created

a wealth of easily accessible backgound information; some of the most interesting works are given

in the bibliography of this Database.

 

Far less accessible is Madagascar's geological information. Mr H Besairie's classic, the

two-volume "Gites MinŠraux de Madagascar", is unfortunately out of print. The extensive gold

bibliography on Madagascar by French authors (appendix 1 to this Database) is very difficult to

access and some items have apparently been lost.

 

However the modern gold explorer in Madagascar still has (as of 1996) some reliable basic

information to guide exploration. Apart from the various works mentioned in the bibliograhy

(Chapter 9 of this Database) three sets of maps are strongly recommended for any exploration work

in Madagascar.

 

They are:

 

MADAGASCAR GEOLOGICAL MAPS AT 1 : 1,000,000

By H. Besairie

 

Projection: Conforme Laborde.

The point X = 800km and Y = 400km

has for geographical co-ord Lat 21§ & Long. 49§E, Paris.

 

See Sketch 5/2 in this Database for sheet coverage.

 

Sheets

 

A  =  North Sheet   (Feuille du Nord)

B  =  Central Sheet (Feuille du Centre)

C  =  South Sheet   (Feuille du Sud)

 

N.B. Only 2,500 printed in 1965 at Antananarivo.

 

These maps may be purchased from: Service Geologique

BP 280 Antananarivo 101

Madagascar

_________________________________________________________________

 

 

MADAGASCAR GEOLOGICAL MAPS AT 1 : 500,000

Author: H Besairie

 

Projection: Conforme Laborde.

The point X = 800km and Y = 400km

has for geographical co-ord Lat 21§ & Long. 49§E, Paris.

 

See Sketch 5/2 in this Database for sheet coverage.

 

Sheets:

 

1  =  Diego Suarez (now Antsiranana)

2  =  Antalaha

3  =  Majunga (now Mahajanga)

4  =  Tamatave (now Toamasina)

5  =  Tananarive (now Antananarivo)

6  =  Morondava

7  =  Fianarantsoa

8  =  Ampanihy

 

N.B. Only 1,000 copies printed in 1972, Antananarivo.

 

These maps may be purchased from: Service Geologique

BP 280 Antananarivo 101

Madagascar

_________________________________________________________________

 

MADAGASCAR TOPOGRAPHICAL MAP (AERONAUTICAL) AT 1 : 1,000,000

Projection: Conformal Conical Projection,

Standard Parallels 1§20' and 6§40'

Convergence Factor . 06979

 

See Sketch 5/2/1 in this Database for sheet coverage.

 

Sheets:

 

N6  =  North of 15th Parallel

P6  =  Between 23rd and 15th Parallels

O6  =  South of 23rd Parallel

 

N.B. Each map is subdivided into four individual maps at 1:500,000 scale.

 

Civilian users may purchase these maps from the following address:

 

DMA Combat Support Center

ATTN: DDCP

Washington DC 20315-0020

USA

_________________________________________________________________

 

These three products are of excellent and still unsurpassed quality. The first two can be

purchased in Antananarivo (although the supply will inevitably run out); the third can be ordered

in the USA.

 

The two sets of maps at 1:1,000,000 (geological and topographical) can be overlayed on each other

only locally due to a different projection system (the French-generated maps use the now obsolete

Laborde co-ordinates system.

 

If a Geographical Information system is used to generate one's own maps, IMR strongly recommends

using the Conforme Conical Projection used by the US Air Force.

 

These three documents alone (see sketch 5/2 and 5/2/1) are adequate for reconnaissance work. More

detailed geological maps at 1:200,000 are also available at Antananarivo but their coverage of

Madagascar is incomplete and several maps are now out of print.

 

Madagascar's "Institut GŠographique et Hydrographique National (Foiben-Taosarintanin'i

Madagasikara = FTM) publishes a series of maps of Madagascar at the 1:500,000 scale and an

excellent, informative, and up to date road map at the 1:2,000,000 scale.

 

Air photos are available but they are old, subject to restrictions and to tiring beaurocratic

haggles. On the other hand, excellent satellite images (particularly the French SPOT coverage)

are readily available outside Madagascar and can be conveniently blown up, up to the 1:50,000

scale. IMR strongly recommends their use: the morphology of Madagascar's highlands, where most of

its gold districts are, is ideally suited to satellite-image interpretation. Modern Global

Positioning System instrumentation can now assure a level of accuracy not previously available in

any published map of Madagascar.

 

 

5.3 INSTITUTIONAL AND ECONOMIC FRAMEWORK

 

    5.3.1. The Government

 

Sketch 5/3 outlines the present political structure of Madagascar. The uncommonly large number of

ministries (21) reflects its French political heritage. Historically, the number of these

ministries is periodically pruned in times of political reform, then start to regrow immediately

afterwards to accommodate the need of political patronage, regardless of the political party in

power.

 

The unusual combination of combining the offices of Prime Minister with the Ministry of Defence

is an insurance policy against military coups. So is the fact that the national police reports to

the Ministry of Defence (Prime Minister, really) rather than the Ministry of Interior.

 

This unusual constitutional arrangement has now been tested for only two and half years, but it

seems to work. The main area of friction remains between the respective powers of the

popularly-elected President and Head of State, and the National Assembly-elected Prime Minister.

 

The town of Antananarivo is chronically plagued with rumours of coups. This goes back for at

least 30 years. The inexperienced visitor is well advised to dismiss them and under no

circumstance demonstrate the least interest in the subject.

 

The Government is now seriously committed to regional decentralisation, with new regional

authorities known as Collectivit‚s Territoriales D‚centralise‚s (CTDs) elected by their own

special elections. It is impossible to say at this stage if the CTDs will have some control on

local mining operations. It is possible, particularly in environmental matters.

 

Mining and exploration activities remain controlled by the Ministry of Energy and Mining through

its two main Departments of Mines and Geology.

 

Unfortunately, a dualism of function remains in the mining sector with the presence of OMNIS,

which operates in the mining field, particularly in oil exploration and chromite production.

 

OMNIS was created directly by president Ratisraka in 1975 in the heyday of military government.

OMNIS originally meant "Office for Military National Strategic Industry", now renamed to "Office

for National Mining and Strategic Industry" and reportd directly to  the President.

 

The status of OMNIS is somewhat anomalous in a civilian government, and Kronsten in 1994

mentioned "reforms urged by the World Bank, which exercises considerable influence on the current

coalition government, include the privatisation of the parastatal OMNIS". To this date (the last

quarter of1995) this privatisation has yet to take place.       

 

Other ministries likely to affect any important mining operations are the Ministry of Finance and

Budget (export permits, taxation regime etc) and the Ministry of Civil Service (labour contracts

and relations).

 

 

    5.3.2. The Economy

 

Madagascar was classified by the World Bank in 1992 as one of the world's poorest countries. In

that year, according to estimates by the World Bank, Madagascar's gross national product (GNP) -

measured at average 1990-92 prices - was $US 2,809M, equivalent to about $230 per head.

 

In 1985-92, it was estimated that GNP per head declined, in real terms, by an annual average of

1.7%, while the population increased by an annual average of 3.1%. Madagascar's gross domestic

product (GDP) increased, in real terms, by an average of 1.1% per year in 1980-92. The growing

gap between population and economic growth is obvious.

 

The rural economy accounts for 80% of Madagascar's export revenues and supplies most of the raw

materials for industry. In 1992 the agricultural sector (including forestry and fishing)

accounted for 33% of GDP and engaged an estimated 76% of the country's labour force.

 

The production of both food and export crops, except cotton, either stagnated or declined after

President Ratsiraka took power in 1975, mainly as a result of the imposition of a doctrinaire

form of socialism. The presence of North Korean "advisers" obviously did not help. The imposition

of co-operative state farms on a reluctant peasantry also contributed to the agricultural

sector's poor performance.

 

Between 1980 and 1992 agricultural GDP increased by an annual average of 2.4%, still considerably

below the population growth rate.

 

The forestry sector has been badly neglected, and 81% of domestic fuel needs are supplied by wood

and charcoal. In 1991, according to a FAO estimates, about 26% of the land area was covered by

forests. A $66M aid arrangement was agreed to at a donors' meeting in Paris in February to

support the first stage of a long-term environmental action plan.

 

In August 1989 a "debt-for-nature" exchange, the first in Africa, was arranged: the USA gave the

Worldwide Fund for Nature $US 1M to buy $ 2.1M of government commercial debts at a 55% discount

from a consortium of international banks, and to use the money for environmental projects. This

imaginative scheme proved successful and further debt-conversion agreements, involving

international organisations, were subsequently negotiated.

 

Paddy rice is the main Malagasy crop. It is grown by 70% of the population whose basic food is

rice (the average annual consumption is about 135 kg per head, the highest in the world).

 

Paddy rice output in Madagascar averages about two tonnes per hectare. Madagascar, once a rice

exporter, has become a net importer since 1982, although improved economic policies can correct

this imbalance in the future. Other important staple crops are maize, cassava, bananas and sweet

potatoes.

 

Madagascar's main cash crops are coffee, vanilla and cloves. The most important is coffee (97% of

it robusta, although arabica production is encouraged) which in the 1980s accounted for about 24%

of total export earning and engaged 25% of the working population. In some Madagascan goldfields

coffee vies with artisanal gold mining in land use, with changes from one activity to the other

according to gold and coffee prices.

 

Madagascar's coffee production for the 1980s was generally about 82,000 t/y - almost the double

the export quota allocated by the International Coffee Organisation (ICO). Madagascar thus had

considerable quantities for disposal in the non-quota market.

 

Madagascar is the world's largest exporter of vanilla, which accounted for 19% of its total

export revenues in 1992, with about 1,000 t/y production. Madagascar operates a highly effective

price control system on vanilla with Reunion and Comoros. Production of cloves in the early 1980s

was around 10,000-12,000 t/y and accounted for about a quarter of export earnings.

 

Other significant Malagasy crops are cotton, sisal, sugar, groundnuts, pineapples, coconuts and

tobacco.  

 

 

    Industry

 

Industry accounted for 14% of Madagascar's GDP in 1992; the sector employs only about 3% of the

working population - not an uncommon figure for central Africa.

 

The island's major industrial centres, other than mines, are located in the High Plateau or near

Toamasina port. Food processing accounts for 49% of all industrial value added. Textiles was

formerly the second largest sector but it has been now superseded by brewing, paper and soap.

 

There are cement plants at Mahajanga and Toamasina, supplied with good quality local limestone.

However, in the late 1980s average annual production of cement was only about 40,000 t

necessitating imports of about 250,000 t/y.; by 1990 production had declined to a paltry 20,000

t.

 

A fertiliser plant at Toamasina, which began operation in 1985, produces 90,000 t/y of urea and

ammonia-based fertilisers. Other industries include the manufacturing of wood products. Most

industrial plants in Madagascar have been operating recently at less than one-third of their

installed capacity.

 

In 1986 the government introduced a new investment code, which provided incentives for domestic

and foreign private investment in activities outside the public sector, particularly in

manufacturing for the export market.

 

The country's fifth investment code, enacted in 1990, introduced incentives to attract foreign

private investors. This code was strongly opposed by many politicians and local business people.

 

Rules regarding foreign exchange and the number of expatriates which can be employed have been

relaxed and tax incentives were introduced, including a five-year holiday from corporation tax.

 

A number of export processing zones (EPZ) have been established and have attracted foreign

investors from South East Asia, France and Mauritius. Labour is cheaper and corporation laws are

lower in Madagascar than in France or Mauritius but the risks are higher for companies producing

for export. One common complaint by Asian investors has been the still modest education of

Malagasy labourers, as in the rest of Africa.

 

In the early 1990s the IDA approved a credit of $48M to finance the development of private

enterprise through training of personnel, the restructuring Madagascar's Chamber of Commerce, and

the establishment of an investment promotion agency. These initiatives, although unquestionably

praiseworthy, had practically no effect on the mining sector.

 

 

    5.3.3. The Mining Sector   

 

    General Information

 

The high French expectation of Madagascar's minerals at the time of its colonisation (1895) never

materialised.

 

The then vigourous gold production has ceased for decades to be an organised (taxable) activity

and does not now contribute to government revenue. The promising coal deposits of Sakoa (a major

preoccupation for the French steam fleet of the time) never really took off, the enthusiasm for

Madagascar's uranium was short lived and doomed.

 

Bulk commodities such as iron ore, bauxite and oil shales were condemned from the start by lack

of local industry or export infrastructure. Oil exploration has been particularly disappointing

with company after company drilling a few desultory holes in Madagascar's Karroo formations and

then withdrawing. In the '90s only chromite, graphite and mica survived as organised mining

activities and none was particularly wealthy. Madagascar is essentially an agricultural economy.

 

IMR's own impression is that Madagascar suffers "exploration fatigue" out of proportion with its

objective, and still largely untested, mineral potential. Foreign explorers eschew Madagascar.

Original geological work is minimal and no new ideas seem to be generated by an anaemic mining

sector. A country that only 30 years ago was one of the most advanced in central and east Africa

now languishes behind mosts in ideas, investments and energy; at least in the mineral sector. 

 

     The Malagasy Mining Code

 

In Appendix 2 to this Database is given the (barely readable) official version of Madagascar's

latest Mining Code (Law No. 88-06) of August 26, 1988. This bulky document consists of 121

articles. It has been drafted for the stated objectives of:

 

1) Creating a favourable climate, from the juridic, fiscal, technical and social perspectives, to

attract new investment in the [mining] sector and therefore to complete similar measures taken in

the whole national economy;

 

2) Decentralising the [mining] administration for better serving the general interests;

 

3) Increasing the professionalism of the [mining] sector, putting in places a set of clear and

appropriate rules in a way to offer a framework for the rational and optimum development of

national mineral resources.

 

 

This document unquestionably improves the terms for foreign investors but it still remains an

untested document, as Madagascar has failed to attract large new mining investors. Since the

nationalisation of the chromite industry in 1976 no major international mining firm has been

operating in Madagascar.

 

In addition, some important new mineral projects (oil, coal and petroleum exploration) have been

negotiated directly with the parastatal OMNIS organisation and not with the Ministry of Energy

and Mining (see sketch 5/3); this has tended to create some confusion.

 

In IMR's opinion the 1990 mining code is perfectly adequate and flexible enough to open serious

negotiations on exploration for large gold projects in Madagascar. 

 

 

    Madagascar's Minerals

 

Chromite and graphite are the only minerals currently exploited in substantial volumes in

Madagascar. Their contribution to the GDP is less than 1%.

 

Madagascar is the world's tenth largest chromite producer with output at around 110,000 t in

1994, down from about 200,000 t/y in 1976 when OMNIS took over from Pechiney. This chromite

production, negligible by South African standards, is however larger than the production of

Australia, Japan, US and China combined.

 

With chromite prices (April 1995) about $ 70-80 per tonne Madagascar's total chromite production

is only worth about $9,000,000. This is equivalent to about 708 kg of gold or one fifth of

Madagascar's estimated "artisanal" gold production of 3-4 t Au/year.

 

Arguably then, even now gold is by far the most important mineral product in Madagascar, even if

the benefits from it do not reach the population at large. Which is, of course, deplorable.

 

 

    Graphite

 

Graphite production, the second largest "official" mineral product in Madagascar, totalled 10,600

t in 1992, down from 18,500 t in 1990.

 

The graphite industry in Madagascar is a very old and tired one. Without new investments,

Madagascar's graphite industry will be seriously affected by the competition of its more

aggressive neighbours. These neighbours - in a geological sense at least - are starting to

exploit the Malagasy type of graphite in their own territory: the Ancuabe mine (5,000 t/y) in

Mozambique, the Graphtan Merelani mine (15,000 t/y) in Tanzania, the Maranamadurai mine

(15,000-20,000 t/y) in Southern India. All these mines were commissioned in the period 1994-5 and

they are producing the same product (large flake graphite, >98% C) as Madagascar and therefore

significantly eroding Madagascar's world market share.

 

    Other minerals

 

Along with Canada, Madagascar is one of the world's few producers of phlogopite, with exports of

1,800 tonnes in 1990, mostly by semi-artisanal operations around Tolanaro-Amboasary in the

extreme south-east of the island. A small percentage of the production is in the form of sheet

mica.

 

Madagascar also produces marble, a variety of construction materials, soil conditioners, and

semi-precious stones (amethysts, tourmaline, beryls, and garnets).

 

Bauxite deposits at Manantenina in the south east are estimated at 100 Mt and have been assessed

for decades by French, Soviet and more recently Italian and EU experts. The bauxite quality is

acceptable (barely: 38% Al2O3) but the total lack of infrastructure and Madagascar's fragile

environment work against its exploitation.

 

The coal deposits of Sakoa have been known for more than a century and the stated reserves are

>100 Mt. A number of companies including the Australian BHP have carried out evaluation in the

past but, once again, lack of infrastructure would make exploitation uneconomic.

 

 

    Ilmenite

 

The largest project under consideration is the extraction of ilmenite from an area of rainforest

and sand dunes at Toalagnaro on Madagascar's south-east coast.

 

Under a letter of intent signed in November 1994 by Quebec Iron and Titanium (QIT, a subsidiary

of the RTZ group) and the state mining group OMNIS, extraction could take place for 30 years and

it is estimated will earn up to $550 million.

 

The project will involve the construction of a new port and other infrastructure. The project has

attracted considerable flak from international environmental groups, concerned - among other

things - about the biodiversity of Madagascar's rainforest.  

 

In the case of Malagasy mineral sands the alarm seems premature.

 

Madagascar's ilmenites present several extraction problems (Bartle, 1988). The deposit is low

grade and the ilmenite is of sub-standard quality. Its unacceptably high Cr2O3 and manganese

content and highly radioactive (Th/P) contaminants will require costly treatment processes before

a commercial product can be obtained.

 

These deposits have been evaluated for decades by a number of companies and individuals

(including the writer), with mixed reports. It would seem that Malagasy ilmenite is a rather

atypical ore and apparently only suitable for the production of a chlorinatable slag - not QIT's

preferred route for its products. It is therefore doubtful that Madagscar's ilmenite will be

exploited any time soon (IMR's opinion). The fact that Malagasy authorities should insist on a

vigorous and conclusive evaluation of its mineral sands (as Mozambique is doing) is entirely a

different matter.

 

 

    5.3.4. The gold sector

 

In Madagascar's socialistic climate of 1975, the country's gold industry was nationalised (Anon

1994). This was largely a symbolic move as official gold production in the 1970s had dwindled to

2-4 kg/y.

 

In reality the government did not have the resources to implement any policing of Malagasy

goldfields and as soon the gold prices picked up at the end of 1970s "artisanal" gold production

started anew.

 

The distinction between illegal and "artisanal" gold production is a thorny one for any

developing country, and particularly for Africa. The authorities are aware that "artisanal" gold

mining is not either a sustainable or socially constructive activity but they are impotent to

regulate it.

 

Lack of information and an inadequate mining environment has deterred  most foreign companies

from seriously committing themselves to gold exploration in Madagascar.

 

The Government's half-hearted attempts to entice foreign capital towards organised (taxable) gold

production in Madagascar came to little.

 

The public become seriously worried in 1993 when the government gave a little-known Swiss group

exclusive nationwide gold and prospecting rights for 25 years, in return for the placing of up to

$US2 billion in discounted promissory notes from the government (MJ Annual Review, 1995). The

scheme - of very dubious legal validity in any case - was shelved. If anything, this episode

proved the surprising degree of naivety of the Malagasy authorities on mining matters.

 

In late 1994 the government decided to form a gold trading agency through which the ministry of

Energy and Mining would buy the output of private prospectors (see appendix 3). This agency will

deposit sale proceeds with Malagasy central bank and it is designed to boost official revenue at

the expense of smuggling, particularly to India and mainland Africa.

 

Similar schemes have been implemented in other parts of Africa (ie. Tanzania, Angola, Zaire,

etc). The writer - who has participated in several UN or government-sponsored seminars on similar

matters - is unconvinced of the wisdom of such a move. The native gold producer will sell gold to

a government agency only if the price offered is superior to the market one (only China manages

to buy most of the gold from its miners at a significant discount from the international price,

thus creating a commercially viable agency).

 

In other words, to persuade individual miners to part with their gold a government has to

subsidise gold mining. This could mean subsidising an illegal, undesirable and unsustainable

practice with no return for the Government.  

 

The problem is not new. It is occurring in dozens of African countries, in Latin America, in

Papua New Guinea. Each country will react to this problem (because a problem it is) according to

the possibilities and its own political and cultural framework. This is not the place to

elaborate on this.

 

However, it would not seem that individual miners would represent a direct threat to a major gold

explorer in Madagascar. Such an explorer is traditionally attracted by large - and therefore

comparatively low-grade - gold deposits with a substantive vertical expression, often requiring

sophisticated recovery plants. Superficial or alluvial gold deposits are not favourite targets

with such investors. Of 16 major new gold projects under development worlwide in 1995 (Thomas,

1995), none was alluvial.

 

It is IMR's firm opinion that large-scale gold deposits have simply not been sufficiently

explored in Madagascar and, at this stage of knowledge, they constitute a very good potential target.

 


5.4 INFRASTRUCTURE

 

    5.4.1. Roads

 

Madagascar's mountainous topography has traditionally hindered communications. In 1991 there were

34,750 km of classified roads, of which 8,540 were main roads and 18,380 km secondary roads. Only

5,350 km were paved. The rest of the road network is occasionally unusable in the wet season

(November-April) unless using 4WD vehicles.

 

In 1989 the European Development Fund (EDF) granted $10M for road rehabilitation in the north and

west of the country. In mid-1994 a program to rehabilitate a further 500 km of main roads, at an

estimated cost of $8 M, was under consideration by the EDF.

 

The excellent "Carte RoutiŠre" of Madagascar at the scale 1:2,000,000, issued in 1990 by the IGM

(Insitut G‚ographique National) and available in any major bookshop, is all one needs for a

reliable and complete guide to road transport in Madagascar.

 

It should be stressed that all the major Madagascan goldfields (with the possible exception of

Andrarona) are easily accessible with standard 2x4 cars rented from commercial agencies in

Antananarivo.

 

  

    5.4.2. Air transport

 

Domestic air services have always been important in Madagascar, on account of its size, difficult

terrain and often poor quality of other forms of transport. There are 211 government-approved 

airfields (see "Carte RoutiŠre de Madagascar" for their location), two-thirds of which are

privately owned. The only international airport is at Antananarivo.

 

The national airline, Air Madagascar, is two-thirds owned by the government and one third by Air

France. Under the government's new liberalisation measures, Air Madagascar lost its monopoly on

domestic services and in 1992 its heavily subsidised external services were substantially

reduced.

 

Any goldfield in Madagascar is a convenient distance (30-80 km) from an official airport, and

several air charter companies in Antananarivo offer reliable services. Air Madagascar links most

of the major townships with a fleet of Boeing 737 and Twin Otters; the timetable is given in

appendix 4. The service is totally reliable.

Charter plane and (slightly more difficult) helicopter hire are available in Antananarivo at

prices comparable with international standards.

 

    5.4.3. Telecommunications

 

Adequate telephone and facsimile facilities are available in all  major towns. Communications

between Antananarivo and the rest of the world do not present any problem.  Communications by

telephone within different localities in Madagascar can at times be difficult.

 

The use of two-way radios is restricted and requires a special permit.

 

Practically every village in Madagascar is equipped with a small post office. The largest ones

have telephone connections. 

 

    5.4.4. Others

 

Railways and maritime transport play only a very subordinate role in gold mining and therefore

will be dealt very briefly. Madagascar has 1,095 km of railways. Three lines in the north of the

country primarily serve the capital, while the fourth, in the south, links Fianarantsoa to

Mankanara port.

 

In 1986 the World Bank agreed to lend $12m to finance the rehabilitation of the northern railway

and its extensions for a further 40 km.

 

Toamasina and Mahajanga, the principal seaport, suffer from a lack of storage space and

equipment. Toamasina port handles about 70% of Madagascar's foreign trade and was in the process

of being enlarged and modernised, until 80% of the port was destroyed by a cyclone in March 1986.

 

Germany, France, the UK and the World Bank are financing a ongoing project to rehabilitate 10

Malagasy ports. Toamasina is independently managed but the other ports are operated by the

Malagasy Ports Authority. The parastatal SocietŠ Malgache de Tranports Maritimes has four

ocean-going ships, while coastal shipping is mostly handled by private firms. The country has a

total of 18 ports handling a little less than 1 M tonnes of freight a year.


6. GEOLOGY

 

 

    6.1. General information

 

Practically all geological work in Madagascar took place during the French colonial time

(1895-1960) - the golden age of Madagascar's geology. Many first-class geoscientists did their

doctorate theses on various aspects of Madagascar's geology or spent years in the then vigorous

Madagascar Geological Survey (Service Geologique). This service was headed from 1930 to

independence by the still legendary Henry Besairie.

 

Systematic geological mapping at various scales started in 1926. The geological map at 1:200,000

was completed in 1951 and in 1960 the geological maps at 1:100,000, covering almost two-thirds of

the country. Some of these maps are unfortunately out of print.

 

Between the two World Wars intensive exploration took place, identifying deposits of coal,

bitumen, graphite, mica, several precious stones, cement-quality limestone, glass-quality silica

sand and many other commercial minerals.

 

Immediately after WW2, exploration for oil and uranium was actively undertaken, respectively by

the S.P.M. (Societ‚ des P‚troles de Madagascar) and the C.E.A. (Commissariat … l'Energie

Atomique). For a short time Madagascar was a uranium producer, exporting several hundred tonnes

of urathorianites from the T“lan„ro (then Port Dauphin) region.

 

Since the end of colonial rule geological mapping and mineral exploration decreased dramatically

as any computeried literature search can confirm: less has been published on Madagascar's geology

in the 35 years after independence than in the last five years before independence. As a

consequence, and particularly in the non-French speaking world, the geological understanding of

Madagascar has remained grossly inadequate. This is despite the growing interest in Madagascar

because of its pivotal position in Gondwana (Katz and Premoli, 1978; de Wit, 1988; Kroner, 1991).

 

This information gap is actually widening. While more and more literature is generated on

Madagascar's geological neighbours (East Africa, south-west India, Sri Lanka, Antarctica), very

little new information is coming from Madagascar.

 

Another reason for the relative obscurity of Madagascar's geological and mineral endowment is

that although a bibliography on this subject lists several thousand titles (Besairie, 1971), this

literature is not generally available.

 

Mostly it consists of internal reports by Madagascar's Service de Mines and Service Geologique,

and they are difficult to obtain even in Antananarivo. Indeed, the principal sources of

information for this Database are Besairie's various maps and publications (some of them now

unfortunately out of print), supplemented by modern publications on Madagascar's regional geology

and metallogeny.

 

 

    6.2. Madagascar's geomorphology    

 

The geomorphology of Madagascar reflects its underlying geology and either one can be glanced at

in sketches 5/1 and 6/1.

 

The mountainous backbone of the island consists of Precambrian rocks. To the east lies a narrow

coastal plain defined by Cenozoic normal faults which strike NNE-SSW, and impart a striking

linearity of coastline.

 

The western shore is less regular. The Morondava basin lies south of Tanjona Vilanandro (former

Cap Saint Andr‚). To the north of this cape is the Majunga basin, and still farther north is the

Antsiranana (formerly Diego Suarez) basin. These three sedimentary basins are largely in faulted

contact with the Precambrian. The cuesta-forming beds dip gently seawards.

 

This area of Madagascar is sometimes called the "Karroo corridor" and, similarly to other Karroo

regions of Africa, it hosts interesting hydrocarbons, coal and uranium deposits (Premoli, 1995).

 

There are unexplained lacunae in Madagascar's geological records. After the Pan-African event,

principally consisting of thermo-metamorphism around 550 MA, there is essentially no record of

Phanerozoic rocks until the late Paleozoic (Karroo formations). This interval must include the

plant-bearing rocks in which Devonian or Carboniferous flora has been identified but whose

outcrops have not yet been found.

 

Late Paleozoic and younger rocks in the marginal basins show a succession of marine and

non-marine events. But since sedimentary basins play no role (alluvial deposits excluded) in

Madagascar's gold metallogeny they will not be discussed here in any detail.

 

All the known primary gold mineralisations in Madagascar predate the breaking up of Gondwana,

making regional tectonic models (India, Mozambique, Tanzania) particularly relevant. Equally so

is  a good understanding of Madagascar's Basement complex.

 

 

    6.3. Madagascar's Basement complex

 

Precambrian rocks form about two-thirds of Madagascar. They are  exposed continuously from

Tolanaro in the south to Antsiranana in the north (see sketches 5/1 and 6/1). These Precambrian

terrains are often referred to as the Basement or the crystalline Basement of Madagascar.

 

The metamorphic grade of this Basement is generally high, and for almost the whole island varies

between the amphibolite and the granulite facies (Premoli, 1979). Greenschist facies are

comparatively rare. The tectonic history and geology of Madagascar presents several similarities

with both eastern Africa and peninsular India.

 

Madagascar's Basement underwent three major tectonic periods which can be summarised as follows

(from the youngest to the oldest):

 

       After 300 MA               Era of platform cover and great

                                                  tectonic rift

 

       Between 2,600 and 300 MA   Era of intercratonic orogenesis

                                                  and great magmatic reactivations

 

       Before 2,600 MA            Era of cratonisation

 

Madagascar's Basement rocks have been divided into three major systems. From the youngest to the

oldest these are:

 

       The Vohibory System

 

       The Graphite System

 

       The Androyen System

 

Each of these systems has been subdivided into several groups. These groups usually have outcrops

in different locations and consist of different lithologies. As a result the assignment of a

group to a particular system and the age relationship between groups in one system is still to be

determined with confidence in most cases. This problem is exacerbated by the general lack of

modern geochronological data in Madagascar from the last 35 years.

 

Madagascar's Basement rocks have been intruded by several igneous episodes. Some of them may have

contributed to the remobilisation and concentration of gold (model a4, see chapter 6.5). The

principal intrusive phases are indicated below (from younger to older):

 

 

               90 MA:  Cretaceous intrusive complex of Antampombato,

                           consisting of gabbros, syenites, pyroxenites,

                           pridotites and possibly the Itremo carbonatites

 

              500 MA:  pegmatites )

                                          ) of the Pan-African event

              550 MA:  granites   )

 

              850 MA:  granites (poorly known) associated with

                           charnokites

    

             1125 MA:  granites and syenites of Ambatofinandrahana

                           intrusive complex and associated nephelinitic

                           and gabbroic complexes. It compares with the

                           Kibarian orogeny in other parts of Africa

 

             1400 MA:  Andrianamena basic complex, including also

                           ultrabasic rocks (gabbros, pyroxenites,

                           peridotites) which have been metamorphosed to

                           orthopyroxenites, orthoamphibolites, talc-

                           schists and serpentinites

 

             1890 MA:  Intrusive episode (granite, granodiorite)

                           affecting the whole Madagascar basement.