Alfred Wegener proposed that around 225 million years ago, all of Earth's land was joined together in a "supercontinent" surrounded by a single vast ocean. This supercontinent was called Pangaea, and the surrounding ocean was Panthalassa. Eventually, Pangaea broke apart into two separate continents divided by an ocean, called Laurasia and Gondwana. Wegener put forward evidence including matching coastlines and fossil distributions to support his theory of continental drift.

1. CIÊNCIAS NATURAIS – FICHA
“A crosta terrestre é formada por pedaços chamados placas tectónicas, que andam à deriva
sobre a camada de rocha fundida do manto. As forças magnéticas do interior da Terra fazem
com que as placas se desloquem lentamente pelo globo num vai e vem constante.
Alfred Wegener pensou que há cerca de 225 milhões de anos toda a Terra deste planeta estava
unida num "supercontinente" que era rodeado por um único imenso mar.”
1. O que defendia Alfred Wegener?
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2. Como se chamava o único continente e o único mar
existente no Pérmico?
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3. Este continente dividiu-se em dois. Como se chamavam aqueles dois continentes
divididos por um mar? Como se chamava esse mar?
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4. Para apoiar a Teoria da Deriva Continental, Wegener teve que arranjar provas. Quais
eram essas provas? Explique-as.
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5. Indique as críticas à Teoria de Wegener.
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2. 6. Como ocorriam as correntes de convecção?
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7. Indique o nome do rifte existente no meio do Oceano Atlântico.
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8. Diga como são constituídos os fundos dos oceanos. Indique a definição de cada um
deles.
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9. O que sugere o estudo do relevo submarino?
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10. O que permite o paleomagnetismo obter?
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3. 11. O que mostra a análise das rochas dos fundos oceânicos?
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12. Onde se forma a nova crosta oceânica?
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13. Onde se localizam as rochas mais recentes? E as mais antigas?
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14. Qual a explicação actualmente aceite da expansão dos fundos oceânicos?
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15. As placas movem-se sobre que camada?
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16. Indique o nome de 12 placas que conheça.
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4. 17. Como se deslocam as placas tectónicas?
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18. Quais os limites que conhece? Para cada um indique um exemplo e as falhas que em
cada um pode ocorrer.
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19. O que acontece em cada limite?
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BOA SORTE!