Making Use of Geology - the Relevance of Geology and Geological Information to the Development Process in St Vincent and the Grenadines

Richard E. A. Robertson

Introduction

St Vincent and the Grenadines is composed of 30 islands, islets and cays that extend from St Vincent, the largest, southward toward Carriacou in the Grenadines of Grenada (Figure 1). The islands are part of the Lesser Antilles Island arc, a region of active volcanism caused by subduction of the North American and/or South American Plate beneath the Caribbean Plate. St Vincent is relatively young (oldest rocks about 3 million years) and consists of a central axial range of mountains starting from La Soufrière (1,178 m), in the north, to Mount St Andrew (736 m) to the south. The geological history of the island consists of the development and northward migration of a series of volcanic centres (Robertson, 2002). Apart from recent alluvial deposits and beach sands only igneous rocks are found on the island. In contrast the Grenadines are older and have a much more complex and varied geological history. The original volcanic landscape of these islands has been extensively altered by erosion and sea level changes. The main rock types exposed are sedimentary (impure limestone and coral) and igneous in origin.

Figure 1: Location map of St. Vincent and the Grenadines (from CPD, 1986)

Geology involves the study of the Earth as a whole, its origin, structure, composition and history and the nature of the processes which have given rise to its present state (Whitten and Brooks, 1972). It spans a wide range of applied sciences and within recent times have been more appropriately called "Earth Sciences". The earth sciences integrate concepts from all the major disciplines of science, including biology, chemistry and physics. Specialisation and overlap with these sciences have spawned a variety of related disciplines including geophysics, geochemistry, volcanology, environmental geology and petroleum geosciences. Geology impacts on most aspects of society and the application of geological knowledge are an important guide to most aspects of life in both developed and emerging economies. An understanding of geology should form part of everyone's education since it impacts on all aspect of life on planet Earth and underpins efforts at sustainability of life on Earth.

Development of geological resources in St Vincent and the Grenadines

In common with most of the islands of the Commonwealth Eastern Caribbean there is no specific local organisation established for the provision of geological information or for the investigation of the general geology of St Vincent and the Grenadines. The only local expertise available in the geological sciences is employed at the Soufrière Monitoring Unit where provision is made for a 'Volcanologist' to be Head of this Unit. This individual is employed to administer the local aspects of the volcano monitoring program and their expertise is not readily available for assistance with general geological problems. Geological expertise is available in the region and directly accessible to the local authorities through the Seismic Research Unit. This organisation is partly funded by the government of St Vincent and the Grenadines (Table 1) and operates a volcano and earthquake monitoring operation on St Vincent (see Robertson et al., 2003). It has professional geologists on its staff and these individuals are available on request to assist with geological issues in St Vincent and the Grenadines. As in the case of the Soufrière Monitoring Unit, it seems likely that this is not widely known on the island and certainly past experience suggest that it is not realised by the government.

The absence of readily available geological expertise in the Commonwealth Eastern Caribbean is a relatively recent development that occurred during the post-colonial period. During the 1920s K.W. Earle was employed as the Government Geologist to the Windward and Leeward Islands under the United Kingdom Overseas Geological Surveys. He was one of the first to produce generalised geological maps for most of the islands of the Commonwealth Lesser Antilles (Earle, 1928).

During the 1950s and early 1960s P.H.A. Martin-Kaye was appointed as Government Geologist. From 1951-56 he was resident in Antigua and was responsible for the Leeward Islands. From 1956-61 he was based in St Lucia and was responsible for the Windward Islands. Martin-Kaye did extensive field surveys of the islands and much of the present-day information on the economic geology of the Leeward and Windward Islands is based on work done by him dealing with such issues as water-supply, fireclays, pozzolans, heavy beach sands, copper, molybdenum and salt evaporate (Martin-Kaye, 1956-61). There was close collaboration between the first Head of the Seismic Research Unit Dr G.R. Robson and P. Martin-Kaye until he left in 1961.

The formation of the Seismic Research Unit in 1952 gave significant impetus to geological investigation on the islands. Despite its focus on the identification and understanding of active and potentially active volcanic centres, the investigations resulted in generalised geological maps for most of the Eastern Caribbean islands and led to a better understanding of the general geology of the islands. Since its formation the Seismic Research Unit has been asked periodically to provide geological related services to governments, non-governmental organisations, private companies and individuals throughout the Eastern Caribbean.

Geological information and expertise available to St Vincent and the Grenadines

Geological resources available to government, companies and individuals operating in St Vincent and the Grenadines exist in a variety of forms. In the past, geological resources were only available through the University of the West Indies (through the Seismic Research Unit in St. Augustine, Trinidad and the Department of Geology in Mona, Jamaica) and through the employment of visiting experts from outside the region. However, within the past 10 years several Vincentians have been trained in the field of geology and information and expertise has become more readily available locally. Information is now available on request from a number of sources and the potential exists for it to make a meaningful impact on the future development of the nation.

The Soufrière Monitoring Unit

The Soufrière Monitoring Unit was established in 1987 and although it has essentially served as a volcano monitoring agency, it has been engaged in some geological work. The day-to-day operation of the Unit is concerned with the maintenance of a volcano monitoring network including frequent visits to the summit of the volcano for the purpose of visual observation. It has collaborated with the Seismic Research Unit in the maintenance and development of the volcano monitoring network for the Soufrière volcano. The Unit has in the past conducted investigations of geological hazards including landslides and coastal erosion (Robertson, 1988, 1989a, 1989b, 1990). More recently, it has also been engaged in public education focusing on improving the level of public knowledge and understanding with regards to geologic hazards, particularly as regards the Soufrière volcano.

The Seismic Research Unit

Since its formation in 1952 and the departure of Martin Kaye, the last Government Geologist employed in the Eastern Caribbean, the Seismic Research Unit has taken over the role of a geological survey unit for most of the islands of the Eastern Caribbean. From its inception it has promoted the investigations into the geology of the islands and have itself been involved in the mapping of young volcanic deposits and determination of their geological history. This has been done with a view towards determination of the most likely eruptive centres and the possible eruptive scenarios for the future. The unit has also been involved in geological appraisal of the potential economic value of geological materials (Tomblin and Tomblin, 1995). The Unit's main area of operation has been the maintenance and operation of a volcano monitoring network using seismology, geodesy, geochemistry and visual observations. It has provided advise to government and private institutions on a variety of geological problems including:

1. Alternative source of building sand and aggregate
2. Slope stability
3. Heavy mineral deposits and composition for economic exploitation
4. Reported finds of precious stones and possibilities for the local utilization of semi-precious stones.

Visits to the island by foreign specialists

The government of St Vincent and the Grenadines have in the past requested and received numerous visits from a variety of specialists who have investigated specific aspects of the island's geology. These individuals come from various national and international organisations, including universities, government research agencies and commercial interests from outside the region and usually spend short periods (usually not more than a few months and often only a few days) investigating specific problems.

Along with specific requests made by government, applications have been received for exploration permits for petroleum, bauxite, iron ore and several other potentially exploitable mineral resources that exist on the island. On such occasions, foreign geologists have visited and conducted geological and geophysical studies on St Vincent and the Grenadines copies of which are often left with government Ministries.

Written documents and published reports

Research by the Seismic Research Unit staff and foreign geologists working in the Lesser Antilles have resulted in a unique collection of literature references, unpublished reports and correspondence that documents most of the attempts made before and after 1952 to develop the geological resources of the Lesser Antilles (including St Vincent and the Grenadines). Tomblin and Tomblin (1995) summarised this work in a report published in 1995 but originally drafted in 1980. No recent summary has been compiled of geological work done in the 1990s and later. Copies of some of these documents are stored in various government departments, at the Documentation Centre, the National Library and the National Archive but are not readily accessible to persons wishing to obtain such information.

Vincentian geologists

Since 1998 the number of Vincentians studying geology or actively working in the field of geology has increased (Table 2). It is unclear whether this increase was a result of a concerted effort by government to increase its capacity in this area but Geology was listed amongst the subjects given priority by Training Division for the period 1999-2002.

The relevance of geology

Geology has the potential to impact on a number of areas of social and economic activity in St Vincent and the Grenadines. Informed decisions about the future particularly with respect to the environment require a reasonable understanding and knowledge of geology or the earth sciences. There is little evidence that geological information have been routinely used for planning and development purposes in St Vincent and the Grenadines. Personal experience suggests that geological reports and investigations done in the past have been ignored and decisions taken that go against clearly stated recommendations contained in these reports. The well-publicised case of housing development in an area prone to landslide activity at Gibson corner in southeast St Vincent is one of the most well-known examples of geological information being ignored by responsible officials.

In St Vincent and the Grenadines, local geologists are already involved in the assessment of natural hazards including volcanic and seismic activity and mass wastage of hill slopes. Their skills can equally be applied to the investigation of new mineral deposits, oil, gas or water (the precious resources on which our modern technological society is based) as it can be to the assessment of the environmental impact of exploration or mining. Environmental and conservation issues should be part of any major proposal for land utilization and geologists have an important role to play in the planning process particularly as it relates to land use and development. Major building constructions such as roads, dams, and reservoirs also require geological expertise in the investigation of sites and foundations.

Knowledge and understanding of geology has a direct impact on the availability of energy and mineral resources, water resources and quality. The geology and hydrogeology of an area influences the availability, the type and the distribution of the water resources and the preparation and improvement of geological maps are an important phase in any attempts to assess the water resources potential on the island. The preservation of wetlands, erosion, waste management, pollution and remediation are all areas of activity that can benefit from expert geological input.

The impact of geological processes on St Vincent and the Grenadines is demonstrated daily in the incidence and effects of mass wastage processes (Table 3). Landslide damage annually cost thousands of dollars to remedy and is likely to be a persistent feature of the natural environment in the foreseeable future. Prehistoric eruptions of the Soufrière volcano have produced a thick and pervasive cover of poorly consolidated ash deposits that become prone to mass movement due to heavy rainfall and improper land use practises.

The positive impact of improved understanding of geological processes is illustrated in the contrasting effects of the 1902-03 and the 1979 eruptions of the Soufrière volcano. These eruptions demonstrate that proper utilisation of geologic information can lessen the threat from geologic hazards.

Impact of the 1902-03 eruption: This eruption occurred at a time when scientific knowledge of volcanic eruptions was still in its infancy. Pyroclastic flows and surges caused by an explosive eruption on 7th May 1902 killed over 1565 people due to burning and asphyxiation. The 1902-03 eruption resulted in the displacement of 7000 people who needed food and shelter. Nine major sugar estates along with their sugar mills were destroyed and 2000 head of cattle lost. The total damage inflicted by this eruption was estimated to be 60,000 pound sterling (Nanton, 1985).

Impact of the 1979 eruption: The 1979 eruption did not result in any casualties but the estimated cost of repairs required to roads, public buildings, drainage and housing as a result of damage caused by the eruption, was 13.5 million East Caribbean dollars. Banana exports for 1979 declined by 40% below weekly averages and 1/3 of the arrowroot crop already harvested was lost. Approximately 15,000 people were evacuated and had to be provided for in shelters at the public expense. Another 5000 evacuees were accommodated by friends and family but also fed through public provision. The cost of feeding 20,000 evacuees was estimated to have been 91,000 EC$ per day.

Potential options for the future

1. Geologic mapping: Geologic maps provide a depiction of the physical, temporal and spatial character of rock, soil and unconsolidated natural materials and are a unique feature of the geological sciences. They provide a summary of the current interpretation of the multi-dimensional distribution of consolidated and unconsolidated earth materials on and within the earth and provide the basis for ongoing interpretation of any aspect of the geology of the land. Such maps are the primary source of geologic information and have the potential to direct land use and development. They are an essential stage in the assessment of geologic hazard. Limited access to the interior of the islands (particularly St Vincent) have had an impact on the extent of geologic investigations and every opportunity for increased access to exposures in the interior should be taken to improve understanding of the geology of the islands. There should be an ongoing program to map the geology of the islands that comprise St Vincent and the Grenadines. This will ensure that geologic maps more accurately depict the nature of the subsurface geology. Current geological maps and other information should be compiled in a summary document and presented in a manner that is more readily accessible to the general public, businesses and government authorities. This will facilitate the greater use of geological information in long-term planning and development in St Vincent and the Grenadines.

2. Industrial minerals: Knowledge of geological materials underpins most of human society. Everything we have and everything we use comes from our natural resources. Most of the items we use and consume are actual mineral products or they are manufactured from or grown with mineral products. Even agricultural products are produced with the use of mineral products - from fertilizing to harvesting to packaging and, finally, distribution to the consumer. Virtually no aspect of human life could be sustained without minerals. Minerals are used in every facet of our daily living from food production and processing, building, providing shelter/housing to transport, communications, medicine and leisure activities. Therefore, we must explore for and efficiently develop our natural mineral resources. Industrial minerals include all minerals that are being mined for the physical properties that they have, or that they impart on products in which they are being used rather that for their metal-contents. They are generally low-priced commodities when compared to most metals and are sold in bulk. Several studies have already been completed on the potential for commercial exploitation of industrial minerals in St Vincent and the Grenadines. These should be reviewed and a summary document compiled that would guide government policy and response to any future attempts to explore or develop these resources.

3. Quarry operations: A number of private quarries operate throughout the island utilizing mainly basalt and basaltic andesite lava flows and andesitic dome rocks from the older volcanic centres located south of the Soufrière volcano. They produce and sell various types of aggregate (Table 4) that is used in the relatively buoyant construction industry. Their operations appear to be largely unregulated and no remedial work is done to the environment whenever operations cease.

Government (through the Ministry of Communications and Works) uses aggregate of various sizes for road and building construction and obtains these mainly from four local quarries. White sand used for concrete, asphalt and building construction is imported from Guyana approximately every six weeks (~2000-2200 metric tons at EC$50 per metric ton). The Public Works Department resells this sand to private companies and individuals for EC$60 per cubic yard. Importation of sand is apparently an attempt to reduce the damaging impact of unregulated use of local beach sand that occurred in the past. However sand mining at beaches continues to occur in some areas and is still essentially unregulated. Crushed river stone is obtained from river beds at Rabacca and Colonaire by private quarry operations and used in the construction industry. Crushed stone is also imported by at least one private company (Franco Construction) for use locally. Approximately 500 cubic yards of aggregate is consumed by the construction industry every quarter but the statistics available do not allow one to determine the true value of this operation. There is an urgent need for regulation of all aspects of quarry operations in St Vincent and the Grenadines (including the exploitation and use of beach sand). This is one of several areas that can benefit from the employment of a trained geologist by the Ministry of Communications and Works (which appears to be responsible for regulation of such operations).

4 Advice on geological matters: Proposals have been made in the past and continue to be made by overseas companies for government approval to investigate or exploit local mineral resources. These proposals range from oil exploration licences to the use of beach sand in the production of iron ore or for magnetite extraction. In the past government did not have access to local expertise that could provide advice and guidance on these matters. This is increasingly no longer the case and use should be made of the availability of local persons trained in the field of geology. Advice on all aspects of geological hazards and on the proper utilisation of earth materials is areas that can benefit from the input of a trained geologist.

Final words

Geology has had an impact on the development of St Vincent and the Grenadines. The impact of three eruptions of the Soufrière volcano within the past century has been significant and future eruptions are expected. The limitations placed on development of the island's resources are unquestionable. At the same time the volcanic mountains are responsible for the lush vegetation, the abundant rainfall and the rugged beauty that characterises the island. It is time for the available geological information to be used in a pro-active rather than a reactive manner. There is much that can be done with proper planning and meaningful application of the information and expertise that is available. We should not be surprised when the loose ash that drapes the island slides during periods of excessive rainfall. Rather we should be able to identify the areas and times that this is most likely to occur and take remedial action to prevent this movement from being realised. We should not wait for the next volcanic eruption before plans are implemented to cater for this eventuality (and this does not only apply to volcano monitoring installations). We should not place investment in schemes that are unlikely to last due to limitations placed on them by geologic processes such as mass movement and volcanic hazards. We can use the information we have to build environmentally friendly structures and sustainable systems that will not be destroyed by the processes that have formed the island and that will continue to impact on its evolution.

There is a need to regulate the quarrying operations (including the use and abuse of beach sand) in St Vincent and the Grenadines. Unregulated and uninformed exploitation of our geological resources have resulted and will result in depletion beyond levels that are sustainable. We must learn from the example of beach mining. A lot of the damage caused by the exploitation of beach sands resulted from a lack of regulation. In the case of beach mining in the Diamond-Brighton area, we have largely depleted a resource, which in the 1980's was estimated to have a capacity of over 50 years. In a similar way we have left the establishment and operation of private quarries up to the operators and despite the existence of legislation, quarries are essentially left to themselves to develop, operate and terminate. There appear to be no significant attempts at rehabilitation and abandoned quarries with steep cliff faces are a common feature on the island.

Key ministries and departments such as the Ministry of Communications and Works should have geological input in their planning process. This may involve the employment of a single 'Government Geologist' or the redefinition of the roles and responsibilities of persons currently employed in the government service. Significant expertise on the geology of St Vincent now resides within St Vincent or in the Vincentian Diaspora. Government should utilise this fact and not miss the opportunity to obtain access to and use of expertise that is immediately at its doorstep. It has been the case in the past where reports by local geologists have gone unheeded by government and by private and state corporations that requested them (e.g. the Gibson Corner 'fiasco'). This should not be allowed to occur in the future and use should be made of information and expertise that is clearly and readily available 'at home'. We should not continue waste our scarce local resource by going outside the region for geological expertise that is available locally or regionally.

References

CPD. 1986. St Vincent and the Grenadines development plan, 1986-1988: first update, 1987-90. Kingstown, St Vincent: Central Planning Division, Ministry of Finance and Planning, St Vincent.

De Graff, J.V. , and et. al. 1989. Landslides: Their Extent and Significance in the Caribbean. In Landslides: Extent and Economic Significance, edited by E. E. Brabb and B. L. Harrod. Rotterdam: A.A. Balkeman.

Earle, K.W. 1928. Geological notes on the island of Dominica. Geological Magazine 65 (766):169-187.

Martin-Kaye, P.H.A. 1956-61. Geological survey of the Windward Islands. Progress Reports. Castries.

Nanton, P. 1985. Managing natural disasters in St Vincent: An analysis of the 1902/03 and 1979 eruptions of La Soufrière volcano. London: Institute of Commonwealth Studies, University of London.

Robertson, R. E. A., Aisha Samuel, Shepherd John, Lynch Lloyd, and Latchman Joan. 2003. Monitoring volcanic activity at the Soufrière volcano - a model for volcano monitoring operations in small-island nations. Paper read at Beyond Walls Multidisciplinary Perspectives: St Vincent and the Grenadines Conference, 22-24 May 2003, at Methodist Church Hall, Kingstown, St Vincent.

Robertson, R.E.A. 2002. The Volcanic Geology of the Pre-Soufrière rocks of St Vincent, West Indies. PhD, Department of Geography and Geology, University of the West Indies, Mona.

Robertson, Richard. 1988. Report on Mass Movement at Belmont (Wd.). Kingstown: Soufrière Monitoring Unit, Ministry of Trade & Agriculture.

---. 1989a. Preliminary Observations on Mass Movement at Westwood, St Vincent. Kingstown: Soufrière Monitoring Unit.

---. 1989b. Report on landslide activity at Gaskills, Montreal Watershed. Kingstown: Soufrière Monitoring Unit.

---. 1990. Report on landslide potential at Gibson Corner. Kingstown: Soufriere Monitoring Unit, Ministry of Agriculture.

SRU. 2002. Detailed report for the period July 1 2000 to July 1 2002. St. Augustine: The Seismic Research Unit, University of the West Indies.

Tomblin, J.F., and J.M. Tomblin. 1995. Mineral resources of the Lesser Antilles, West Indies. Keyworth, Nottingham: British Geological Survey.

Whitten, D.G.A., and J.R.V. Brooks. 1972. The Penguin Dictionary of Geology. London: The Penguin Group.

© Richard Robertson, 2003.

HTML last revised 17th October, 2003.

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