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Capítulo Impresso Monte Roraima, RR Sentinela de Macunaíma SIGEP 038 Nelson Joaquim Reis 1 O MONTE RORAIMA, ponto de fronteira trípli- ce entre Brasil, Venezuela e Guiana, com altitude em 2.734 metros, constitui característica feição morfoló- gica em forma de mesa, também chamada tepuy na línguagem indígena Macuxi local. Suas escarpas ver- Mount Roraima, State of Roraima –The sentinel of ticais com mais de 500 metros de altura, da base ao Macunaíma topo, são formadas por arenitos com quase 2 bilhões de anos. A base do monte foi atingida pela primeira The Mount Roraima represents a triple frontier vez em 1595 pela expedição inglesa comandada por landmark between Brazil, Venezuela and Guyana with Sir Walter Raleigh, mas somente em 1884 o botânico 2,734 meters a.s.l. It shows a fascinating morphological table shaped pattern, also called tepuy in the local Macuxi Everard Im Thurn alcançou o topo do legendário mon- indian language. Its more than 500 meters vertical scarps te pelo lado venezuelano. O relatório desse botânico from bottom to top are formed by nearly 2 billion years serviu de fonte de inspiração para Arthur Conan Doy- old sandstones. The base of Mount Roraima was reached le escrever o livro “O Mundo Perdido”. O monte tem at first in 1595 by Sir Walter Raleigh, but only in 1884 para os indígenas Macuxi do Brasil grande significado the botanist Everard Im Thurn reached the top of the espiritual, sendo referido como a “Casa de Macunaí- legendary mount, arriving from its venezuelan side. The ma”. Geologicamente, representa um marco da estra- report of this botanist was a source of inspiration of Sir tigrafia do Supergrupo Roraima, uma bacia sedimentar Arthur Conan Doyle´s fiction novel “The Lost World”. de idade paleoproterozóica do Escudo das Guianas, The table shaped mount has a spiritual meaning for the norte do Cráton Amazônico. A Formação Matauí re- brazilian Macuxi indians, who called it the “House of presenta a unidade de topo do Supergrupo Roraima e Macunaíma”, a legendary god. Geologically, it represents registra três principais fácies sedimentares, essencial- a stratigraphical landmark of the Roraima Supergroup, mente areníticas a conglomeráticas: maré a marinho being the register of a paleoproterozoic sedimentary basin raso, eólico e fluvial anastomosado indicando uma re- in the Guyana Shield, the orthern portion of the Amazon gressão marinha. O Monte Roraima permanece como Craton. The top stratigraphic unit of Mount Roraima, the Matauí Formation, represents the uppermost part of grande atrativo ao turismo ecológico (trekking), con- the Roraima Supergroup that is built up mainly by tudo, com acesso possível apenas pelo lado venezue- sandstones and conglomerates representing three lano, apesar de também pertencer ao Brasil. sedimentary facies: tidal to shallow marine, eolic and Anualmente um grande contingente de turistas tem braided fluvial that indicate a marine regression. Mount acesso ao monte, tornando-se necessária a preserva- Roraima remains as an important attraction for ecotourism ção deste monumento estratigráfico no que se refere (trekking), although with a permanent trail only accessible à manutenção de seu estado primitivo, considerando- at the venezuelan side. Throughout the year a great se (i) suas únicas e belas feições erosionais (escultu- number of trekking tourists visit the mount. Preservation ras naturais em rochas), assim como (ii) as feições of the area must be regarded taking in account (i) its sedimentares abundantemente retratadas em litologi- unique and beautiful landscape of sandstone erosional as areníticas e indicativas de paleoambientes forma- forms, as well (ii) the preserved sedimentary structures dos a centenas de milhões de anos atrás. that represent the register of a atural environment of the Earth that occurred several hundreds of million years ago. Palavras-chave: Monte Roraima; Supergrupo Key words: Mount Roraima, Roraima Supergroup; Roraima; Matauí; Paleoproterozóico; Escudo das Matauí Formation; Paleoproterozoic; Guyana Shield Guianas 90 Monte Roraima, RR INTRODUÇÃO Brasil e Paikora e Waruma, afluentes da margem es- querda do rio Mazaruni na Guiana. O Monte Roraima (Fig. 1) constitui uma mesa ou Na porção brasileira, o Parque Nacional Monte tepuy, cujas rochas sedimentares assinalam a frontei- Roraima foi criado pelo Governo Federal através do ra tríplice entre o Brasil, Venezuela e Guiana. De sua Decreto 97.887 de 28 de junho de 1989 e ocupa uma área total, apenas 5% encontra-se no Brasil, cabendo área de 116 mil hectares. Como parque, tem assegu- 10% à Guiana e 85% à Venezuela. Importantes bacias rado pelo Instituto Chico Mendes de Conservação da hidrográficas têm nessa localidade suas nascentes, Biodiversidade – ICMBio a preservação integral de sua citando os rios Arabopó na Venezuela, Cotingo no flora, fauna e demais recursos naturais, mantendo Figura 1 - (a) Vista do Monte Roraima (à direita) e Monte Cuquenán (à esquerda); (b, c) Topo do Monte Roraima e vista dos paredões do Monte Cuquenán; (d) paredões do Monte Roraima; (e) cavidades métricas no topo do Monte Roraima. Figure 1 - (a) View of Mount Roraima (at right) and Mount Cuquenán (at left); (b, c) Top of Mount Roraima and view of Mount Cuquenán; (d) cliffs of Mount Roraima; (e) metric sinkholes at the top of Mount Roraima. Sítios Geológicos e Paleontológicos do Brasil 91 Figura 2 - Feições de erosão ruiniformes em rochas areníticas no topo do Monte Roraima. Figura 2 - Ruinform erosion features in arenitic rocks on the topo of Mount Roraima. suas características geológicas, geomorfológicas e cê- Roraima é um dos estados brasileiros que conta nicas e proporcionando oportunidades controladas com uma das maiores populações indígenas do país. para visitação, educação e pesquisa científica. Seus Em sua porção setentrional reúne as etnias Ingaricó, limites se fazem a oeste e leste respectivamente atra- Taurepang, Patamona, Uapixana e Macuxi. Na bacia vés da fronteira com a Venezuela e Guiana. É uma do rio Cotingo, no seu alto curso, concentram-se os região recoberta em grande parte por vegetação de indígenas Ingaricós. Para leste, em direção à divisa savana estépica, entrecortada por rios e cachoeiras, com a Guiana e bacia do rio Maú ou Ireng, concen- onde destacam-se os rios Cotingo, Canã, Uailã e Maú. tram-se os índios Taurepang, Patamona e Uapixana e O extremo norte da área é recoberta por Floresta mais para sul, os índios Macuxi. Ombrófila Densa, predominante sobre a savana. A região registra histórica atividade auridiamantí- O Parque Nacional Canaima, na Venezuela, que fera que por décadas ocupou parte da bacia do rio contempla grande parte da região dos montes Roraima Cotingo, dentre outras importantes drenagens. Con- e Cuquenán, tem uma área aproximada de 30.000 km2, tudo, a atividade garimpeira praticamente extinguiu- maior que as áreas dos estados de Alagoas ou Sergipe. se a partir da demarcação e homologação da Terra 92 Monte Roraima, RR Indígena Raposa – Serra do Sol pelo Governo Fede- expedição aos montes Roraima e Caburaí, tendo sido ral em 15 de abril de 2005. realizadas respectivamente medições com GPS de alta precisão, da altitude do Monte Roraima e a determi- LOCALIZAÇÃO nação do extremo norte do país. O recente dado alti- métrico obtido no Monte Roraima veio revelar que O Monte Roraima tem o Estado de Roraima como essa elevação é 5,24 metros menor do que o valor seu ponto locacional em território brasileiro, na por- oficial anterior. ção territorial mais setentrional do país. Situado na O ponto mais alto do Monte Roraima é a Pedra serra Pacaraima, o monte revela característica fisio- Maveric, onde encontra-se o marco de fronteira en- grafia de mesa ou tepuy, cujas escarpas verticais com tre Brasil e Venezuela (BV-0). Seu topo perfaz uma mais de 500 metros de altura são formadas por rocha área de aproximadamente 31 km2, cuja superfície de arenítica. Com uma altitude em r.n.m. de 2.734,06 aplainamento encontra-se por volta de 2.500 metros. metros (IBGE 2005), representa o sétimo ponto mais Elevações rochosas residuais e de dimensões variá- elevado do país. Em junho de 2005 o Instituto Militar veis, normalmente isoladas, ocorrem acima da super- de Engenharia do Exército - IME, Instituto Brasileiro fície de aplainamento. As maiores elevações situam- de Geografia e Estatística - IBGE (Coordenação de se mais ao norte do monte. Geodésia) e a Primeira Comissão Demarcadora de As coordenadas geográficas do marco de frontei- Limites - PCDL sediada em Belém, realizaram uma ra, com datum em SAD 69, são: 05º12’13,57" N e Figura 3 - Mapa de situação do sítio geológico Monte Roraima, porção extremo norte do Estado de Roraima. Na imagem de radar, a linha vermelha representa a fron- teira entre Brasil, Guiana e Venezuela. A linha branca mostra o limite da Formação Matauí, Supergrupo Rorai- ma. Figure 3 - Location map of the Mount Roraima and surrounding areas at the northernmost portion of the State of Roraima. At the ra- dar image the red line represents the frontier between Brazil, Guyana and Venezuela. The white line represents the limit of the Matauí Formation, Roraima Supergroup. Sítios Geológicos e Paleontológicos do Brasil 93 60º42’55,08" W. Está inserido na porção sudeste da motivos óbvios, nunca os dois apaixonados conse- Folha NB.20-Z-B-V (escala de 1:100.000). guiam se encontrar para vivenciar aquele amor. Quando Situa-se a aproximadamente 50 km a oeste do o Sol subia no horizonte, a lua já descia para se pôr. E Monte Caburaí (1.456 m), ponto mais setentrional do vice-versa. Por milhões e milhões de anos foi assim. país (05º17’19,77" N e 60º11’54,51" W). Para leste, Até que um dia, a natureza preparou um eclipse para em território venezuelano, encontra-se próximo ao que os dois se encontrassem finalmente. O plano deu Monte Cuquenán. Para sudeste, pela linha de frontei- certo.
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