. The Earth beneath the sea : History. Ocean bottom; Marine geophysics. TTTHw-^-^^ / Sea level f '.X^'m. (b2) 4- ',V,-> IrSv y'"^^^ Sea eve '\.\'.\\'/^ ' ^ [â ... [i^^'^'TT y--^;^ (c2) I 4- (b1) v: "v^^^ Sea level -'/-^^ '-V' 4- 4- V/~V-\ (C1) 'Â¥\ Barrier reef Sea level \ iV^,. aU^"1'VVV-',V Sea level. Fissure Fig. 10. Types of continental margins, (a) Constructional, subsiding type. Wide shelf, wide and thick sedimentary basin, eastern North America, North-west Europe. (b) 1. Flexured type. No significant sedimentation, Provence (at Nice, no shelf at all). 2. Flex
. The Earth beneath the sea : History. Ocean bottom; Marine geophysics. TTTHw-^-^^ / Sea level f '.X^'m. (b2) 4- ',V,-> IrSv y'"^^^ Sea eve '\.\'.\\'/^ ' ^ [â ... [i^^'^'TT y--^;^ (c2) I 4- (b1) v: "v^^^ Sea level -'/-^^ '-V' 4- 4- V/~V-\ (C1) 'Â¥\ Barrier reef Sea level \ iV^,. aU^"1'VVV-',V Sea level. Fissure Fig. 10. Types of continental margins, (a) Constructional, subsiding type. Wide shelf, wide and thick sedimentary basin, eastern North America, North-west Europe. (b) 1. Flexured type. No significant sedimentation, Provence (at Nice, no shelf at all). 2. Flexured type with narrow shelf and sediinentary wedge. Intermediate between (a) and (bl). Probable examples, West and South Africa, (c) 1. Faulted type. Irregularities in basement filled up by sedimentation. Probable example, Queensland. 2. Block-faulted type. Sedimentation in dowTifaulted basins, erosion on ranges, continental borderland of Southern California, (d) Fissured type. Glacial overdeepening in transverse valleys, Norway, Labrador, East Antarctica. According to Bourcart (1938, and other papers), the flexured type is very widespread throughout the world ; he even thinks that this is the normal type of contact between land and sea. If the hinge line migrates outwards, it follows that a part of the sea-bed becomes dry land, and the contrary happens if the hinge line migrates inwards. Although Bourcart does not deny the existence of eustatic fluctuations of sea-level during the Quaternary, he tends to relate the emerged beaches to continental flexures rather than to eustatism. Umbgrove (1947) is in favour of many of Bourcart's ideas. Jessen (1943) has also come to similar conclusions in his book, in which all large coastal units in the world are considered. He points out that the marginal regions of the continents are often higher than the inner parts of them (India, Africa, Scandinavia, etc.), a fact. Please note that these images are extracted from scanned pa
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Keywords: ., bookcentury1900, bookcollectionbiodivers, booksubjectoceanbottom
