Southern Brazilian Marine Mineral Occurrences and Deposits · the local, regional and global scale. Such a programme must aim at documenting the distribution and physical setting

GRAVEL ISSN 1678-5975 Janeiro - 2003 Nº 1 25-39 Porto Alegre

Financial Support: Organization of American States – OAS, Ministério da Ciência e Tecnologia – MCT, Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq.

Southern Brazilian Marine Mineral Occurrences and Deposits L. R. Martins*; E. G. Barboza* and F. Caruso Jr.* * South West Atlantic Coastal and Marine Geology Group – COMAR, Upper South West Atlantic Program – ASOS (Brazil, Uruguay, and Argentina)

RESUMO São apresentadas descrições relativas a ocorrências e depósitos de

minerais marinhos presentes na Zona Econômica Exclusiva (ZEE) do sul do Brasil. As informações fornecidas representam uma contribuição do Grupo de Geologia Costeira e Marinha do Atlântico Sudoeste (Brasil, Uruguai, Argentina), à base de dados MARMIN (INFREMER) e foi elaborada tendo por fonte resultados já publicados, provenientes de vários projetos de pesquisa desenvolvidos na área compreendida entre São Francisco do Sul (lat 26º 15’ S) e Chuí (lat 33º 45’ S).

Os dados produzidos incluem ocorrências e depósitos de minerais pesados, carbonato bioclástico, areia quartzosa, concreções fosfáticas e turfa. Tais recursos minerais foram acumulados durante a evolução paleogeográfica da área durante o Quaternário.

ABSTRACT Descriptions of marine mineral occurrences and deposits of the Southern

Brazil Economic Exclusive Zone (EEZ) are presented. The furnished information represents a contribution of the South West Atlantic Coastal and Marine Geology Group–COMAR (Brazil, Uruguay, Argentina) to the MARMIM data base (INFREMER), and was based on published results of several research projects developed in the area from São Francisco do Sul (lat 26º 15’ S) to Chuí (lat 33º 45’S), along the south Brazilian Coastal Zone.

Data include occurrences and deposits of heavy minerals, bioclastic carbonate, quartzose sand, phosphatic concretions and peat. These mineral resources were accumulated during the Quaternary paleogeographic evolution of the area.

Keywords: marine minerals, occurrences, deposits.

L. R. Martins; E. G. Barboza and F. Caruso Jr.

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INTRODUTION In order to promote the research on

marine minerals in the Economic Exclusive Zone (EEZ), the Institut Français de Recherche pour l’Exploitation de la Mer (INFREMER) published their available data, in printed form (LENOBLE et al., 1995).

According to the authors, an “occurrence” is defined as a quoted presence of minerals in a determined location with insufficient information to designate it as a deposit. A “deposit” is a well documented mineral occurrence that could be considered as a future objective for mining; while an ore deposit is a well known deposit that can be mined in the present economic and technical conditions.

At the moment, a large number of marine projects are underway, sponsored by various international bodies (governmental and non-governmental), which support research on coastal and marine geology and associated mineral resources. Special periodical meetings are also devoted to the subject (Underwater Mining Institute Conference, IMMS International Geological Correlation Program. IGCP Project 464 Meetings and others).

In the South West Atlantic, the Programme on Ocean Science in relation to Non Living Resources–OSNLR, sponsored by the Intergovermental Oceanographic Commission–IOC (UNESCO), in cooperation with the governments of Brazil, Uruguay an Argentina, promotes a series of projects with important results for the region between Cabo Frio (Brazil) and Peninsula Valdés (Argentina).

Economic and social significance was considered to be addressed by focusing on a limited number of resources, specially i) placers (including sand and gravel); ii) phosphorites; iii) carbonates (coral reefs and bioclastic); and the iv) coastal zone as a resource (problems related with erosion, siltation and the impact of man on the physical environment of the coastal zone). To reach these objectives, the regional component of OSNLR (1986-2002) also developed studies to obtain information required to better understand these commodities. The most relevant ones were:

a) Sea-level changes whether global

(eustatic), as result of world cooling on warning,

or local, resulting from rising or lowering of sea-level, related to local crust movement.

b) The formation, location and interrelationship of the various environments of deposition and the type and distribution of sediments (and their related biota) within those environments.

The tectonic (or neotectonic) framework of the coastal zone affecting not only relative sea-level change and the nature and distribution of environments, but in some cases, the localization of a potentially economic resource.

DISCUSSION In relation to the Brazilian Economic

Exclusive Zone, the INFREMER publication (LENOBLE et al., 1995) refers to the following occurrences:

143 – Ceará Seamount (phosphate) 145 – North Belém (phosphate) 147 – Aracajú East (phosphate) 148 – Caravelas East (phosphate) 149 – Southern Brazil (phosphate) 263 – Bahia Coast (lime) These occurrences are located between

the Latitude of N 03º’05’ to Latitude S 22º 04’ (Figure 1).

The Programme OSNLR (IOC/UNESCO, 1985) grouped the resources (Figure 2) in terms of scientific and/or economic importance. According to this point of view, those commodities can be considered to fall into three groups:

− Those which are of no great

economic or scientific interest on a global basis. − Those which are of no immediate

economic interest but of considerable scientific interest as polymetallic sulphides, metalliferous muds, polymetallic nodules and crusts.

− Those which are of economic and scientific interest ranging from moderate to high, as in the case of oil and gas, coal, carbonate sediments, phosphate, heavy minerals placers, sand, gravel and the coastal zone (Table 1).

Southern Brazilian Marine Mineral Occurrences and Deposits

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Figure 1 – Location map of the mineral occurrences and deposits of the Brazilian continental margin

(modified LENOBLE et al., 1995).

Regarding the coastal zone, OSNLR considers that approximately 70 per cent of the world’s population lives in this area, and there are tremendous pressures and demand exerted upon this fragile environment. It is, in fact, one of the most exploited and endangered regions on Earth.

Overdevelopment of shores and wetlands, dwindling sites on land for the

disposal of human generated waste, contamination coastal environments and sediments, the disruption of coastal ecosystems and the specter of rising sea-level due to anthropogenically induced global warming are but a few of the pressures humans are exerting on coastal environments around the world (PRATSON et al., 1999).


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Figure 2 – Location of marine mineral deposits (according COOK, 1975).

From a variety of natural and man induced causes, more of the world’s shoreline is eroding than accreting and, at the same time, there is a rapidly accelerating rate of development (residential, recreational and industrial) along the coast. Mining sands, construction on and across beaches (groins, jetties, bulkheads, seawalls and inlet channels), demolition of dunes, and extending buildings onto the foreshore may only aggregate an already serious problem.

Pollution (human and industrial) waste of beaches, estuaries and the nearshore zone is intense in many areas and, in many parts of the world, it is rapidly exceeding all capacities for absorption. Ground water supplies in coastal areas and on oceanic islands are being endangered by salt water intrusion due to over exploitation of coastal aquifer. Dissolved and particulate fluvial inputs and their modifications during transits through estuaries and coastal waters are essential factors of the chemical budget of the ocean. In large part of the oceans, biological production is a function of the flux of nutrients and organic substances from the coastal zone. The OSNLR concept – Coastal Zone as a Resource in its own Right (CZAR) emphasizes the principle of resource.

RESULTS

The new occurrences now described are results of several projects developed along the southernmost portion of the Brazilian continental margin, in the States of Santa Catarina and Rio Grande do Sul (lat 26º 15’ to 33º 45’ S).

They were named as:

1. Santa Catarina – bioclastic carbonate 2. Rio Grande – quartzose sand 3. Bujuru – heavy minerals 4. Albardão – bioclastic carbonate 5. Carpinteiro – bioclastic carbonate 6. Rio Grande Plateau – phosphatic nodules 7. Laguna/Chuí – peat

Details on these occurrences and

deposits could be found in (VILLWOCK et al., 1979, 1983; MUNARO, 1994; MARTINS et al., 1999; WILDNER et al., 1988; SANTANA, 1999; CALLIARI et al., 1999; CARUSO Jr., 1999; CARUSO Jr. et al., 1999; MARTINS and TOLDO Jr., 2002) that published results obtained through the development of several research missions in the last twenty years.


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The description of each occurrence is shown on attached INFREMER model filling card with the sequential OSNLR number from 01 to 07.

FINAL REMARKS

The world ocean holds a variety of mineral and energy resources from which only a part is well explored, and an exception is the hydrocarbon accumulations which continue to play an increasingly important role in the production of world energy. There is also large potential resource, in part commercially mined offshore, as building aggregates and tin.

In some countries, projects on offshore sand for beach restoration were developed like the Sand and Gravel Program of the Minerals Management Service – MMS (US Department of the Interior) and the Sand Inventory Program (US Geological Survey.) Both programs also develop studies on the environmental impacts associated with the dredging operations for offshore sand and gravel. In South West Atlantic, the OSNLR Coastal and Marine Geology Group develops studies in pilot areas, focusing on integrating geologic and environmental information, to identify sand deposits for beach nourishment (MARTINS et al., 1999).

Most scientific research on mineral resources is directed towards the understanding of their formation. This understanding would allow the discovery of more deposits in similar environments. Successful mineral exploration cruises can be best planned on the basis of seafloor maps showing the morphology and the general structural and sedimentation patterns, while knowledge on the prevailing weather conditions and current regime are useful as well.

According to OSNLR guidelines, exploration of marine non-living resources in a manner that is economically and environmentally responsible requires a long-term strategic scientific program, developed at the local, regional and global scale. Such a programme must aim at documenting the distribution and physical setting of marine resources, the control of their formation and, where necessary, the potential impact of their exploitation.

REFERENCES CALLIARI, L. J.; CORRÊA, I. C. S. and ASP,

N. E. Inner Shelf and Beach Seashell Resources in Southern Brazil. In: L. R. Martins and C. I. Santana (editors) Non Living Resources of the Southern Brazilian Coastal Zone and Continental Margin. 39–49. OAS/IOC–UNESCO/MCT. Publication. Porto Alegre. Brasil. 1999.

CARUSO, Jr. Shell Deposits in the Santa Catarina Coastal Area, Southern Region of Brazil. In: L. R. Martins and C. I. Santana. (editors). Non Living Resources of the Southern Brazilian Coastal Zone and Continental Margin. 69-79. OAS/IOC–UNESCO/MCT. Publication. Porto Alegre. Brasil. 1999.

CARUSO, Jr.; MARTINS, L. R.; POTTER, P. E. and WOLFF, I. M. Heavy Mineral Sand Deposits of the Rio Grande do Sul Coastal Plain, Southern Brazil. In: L. R. Martins and C. I. Santana. (editors). Non Living Resources of the Southern Brazilian Coastal Zone and Continental Margin. 50-61. OAS/IOC–UNESCO/MCT. Publication. Porto Alegre. Brazil. 1999.

COOK, P. J. Minerals from the Oceans. In: Resources of the Sea. Royal Society of Tasmania. Symposium. 1975.

IOC/UNESCO. IOC-UN (OETB) Guiding Group of Experts on the Programme of Ocean Science in Relation to Non Living Resources (OSNLR). Reports of Meetings of Experts and Equivalent Bodies. 15 pgs. Paris. France. 1985.

LENOBLE, J. P.; AUGRIN, C.; CAMBON, R. and SAGET, P. Marine Mineral Occurrences and Deposits of the Economic Exclusive Zone. MARMIN: a database. Editions INFREMER, Plouzane, France. 1995.

MARTINS, L. R. Operação GEOMAR IV Costa Sul. Boletim DG 32-IV, Diretoria de Hidrografia e Navegação, RJ: 1-19. Rio de Janeiro, Brasil. 1972.

MARTINS, L. R.; MARTINS, I. R. and WOLFF, I. M. Sand Deposits along Rio Grande do Sul (Brazil) Inner Continental Shelf. In: L. R. Martins and C. I. Santana. (editors). Non Living Resources of the Southern Brazilian Coastal Zone and


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Continental Margin.. 26-38 OAS/IOC–UNESCO/MCT. Publication. Porto Alegre. Brazil. 1999.

MARTINS, L. R. and TOLDO Jr., E. E. Mineral Resources of the Coastal Zone and Continental Shell of Rio Grande do Sul, Brazil. In: L. R. Martins, E. E. Toldo Jr. and S. R. Dillenburg (editors). Erosão Costeira: Causas, análise de risco e sua relação com a gênese de depósitos minerais. CD-ROM OEA/CNPq/MCT. 2002.

MARTINS, L. R. and URIEN, C. M. Evolução Paleogeográfica. Atlas Sedimentológico da Planície Costeira do Rio Grande do Sul. CECO/UFRGS Série Mapas, 2, Carta 9. Porto Alegre, Brazil. 1979.

MUNARO, P. Geologia e Mineralogia dos Depósitos de Minerais Pesados de Bujuru, RS. Curso de Pós-Graduação em Geociências. UFRGS. Dissertação de Mestrado. 96 pgs. 1994.

PRATSON, L.; DIVINS, D.; BUTLER, T.; METZGER, D.; SHARMAN, G.; STEELE, M.; BERGREEN, T.; HOLCOMBE, T. and RAMOS, R. Exposing the U.S. Coastal Zone. EOS. 80 (4). 37. Washington, USA. 1999.

SANTANA, C. I. Mineral Resources of the Brazilian Continental Margin and adjacent oceanic regions. In: L. R. Martins and C. I. Santana. (editors). Non Living Resources of the Southern Brazilian Coastal Zone and Continental Margin. 15-25. 1 map. OAS/IOC–UNESCO/MCT. Publication. Porto Alegre. Brasil. 1999.

VILLWOCK, J. A. and TOMAZELLI, L. J. Geologia Costeira do Rio Grande do Sul. Notas Técnicas 8: 1-45. Mapa. Porto Alegre. Brasil. 1995.

VILLWOCK, J. A.; LOSS, E. L.; DEHNHARDT, E. A.; TOMAZELLI, L. J. and HOFMEISTER, T. Concentraciones de Arenas Negras a lo largo de la costa de Rio Grande do Sul. Memorias del Seminario sobre Ecología Bentonica y Sedimentación de la Plataforma Continental del Atlántico Sur. ORCYT. 415-422. Montevidéu, Uruguay. 1979.

VILLWOCK, J. A.; DEHNHARDT, E. A.; LOSS, E. L. and HOFMEISTER, T. Turfas da Província Costeira do Rio Grande do Sul. Condicionamento geológico de uma fonte energética potencial. Acta Geológica

Leopoldensia 7 (14). 79-92. São Leopoldo, Brasil. 1983.

WILDNER, W.; LOPES, R. C. and CAMOZATTO, E. Turfa na Província Costeira do Brasil Meridional do Chuí a Laguna. Congresso Brasileiro de Geologia. 35º. Anais 6. 2514-2557. Belém, Brasil. 1988.

LIST OF ACRONYMS ASOS – Upper South West Atlantic Program

(Brazil, Uruguay, Argentina). EEZ – Economic Exclusive Zone. IMMS – International Marine Minerals Society.

Honolulu, Hawaii, USA. IGCP – International Geologic Correlation

Program. Project 164. INFREMER – Institut Français de Recherche

pour l´Exploitation de la Mer. IOC – Intergovernmental Oceanographic

Commission of UNESCO. MARMIN – Marine Mineral Data Base of

INFREMER. OSNLR – Programme on Ocean Science in

relation to Non Living Resources. UFRGS – Federal University of Rio Grande do

Sul. USGS – United States Geological Survey. UNESCO – United Nations Educational,

Scientific and Cultural Organization.


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Table 1 – Comparison of Economic Significance and Scientific Effort.

ECONOMIC SIGNIFICANCE SCIENTIFIC EFFORT AVAILABILITY ECONOMIC

POTENTIAL CONTEMPORARY

INTEREST LEVEL OF EFFORT

Sand and Gravel A A C C

Carbonate Materials A B C C

Placer Minerals A A C C

Phosphorites B B B B

Silica Sands A C C C

Calcareus Oozes A C C C

Polymetalic Nodules B B A A

Metalliferous Sediments B B B C

Manganese Crusts C C B B Polymetalic Sulphides C C A A

Oil and Gas A A A A

Coastal Zone A A B A

EXPLANATION OF TABLE 1 AVAILABILITY, is intended to indicate how widespread, throughout the world ocean, deposits of the material are known or likely to be:

A. abundant – in most or many of the regions; B. common – in several regions; C. limited only a few regions.

ECONOMIC POTENTIAL, is intended to indicate the likehood that some proportion of these deposits are now being exploited or could be exploited in response to market forces at some time in the foreseeable future:


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A. high – a significant number of deposits are being exploited and/or are likely to be exploited in the foreseeable future;

B. medium – a few deposits are being exploited and/or may be exploited in the medium term or long term;

C. low – it is unlikely that deposits will be exploited for quite some time.

CONTEMPORARY INTEREST, is intended to indicate the rate of increase of scientific interest in the deposits and the number of researchers that are being attracted to closely related subjects:

A. high – substantial increase of interest and scientists; B. moderate – modest increase in interest and scientists; C. low – little or no increase in interest and scientists.

LEVEL OF EFFORT, is intended to indicate the relative amount of scientific effort that is presently being directed towards closely related subjects:

A. high – a high level of effort; B. moderate – a substantial level of effort; C. low – a modest level of effort.


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Southern Brazilian Marine Mineral Occurrences and Deposits · the local, regional and global scale. Such a programme must aim at documenting the distribution and physical setting

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