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Greater Antilles: Northern Caribbean Plate Kinematics Marine Terrace Data: Puerto Rico |
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Marine-cut Terraces of Puerto Rico On all sides of the island of Puerto Rico, there are sedimentary deposits formed both in alluvial plains and in the sea by rivers transporting material from higher parts of the islands (Monroe, 1980). Some of these deposits are subsequently reworked by the sea and wind (Monroe, 1980). In the northwestern corner of Puerto Rico, there is a marine-cut terrace on which an air force base was built. This marine-cut terrace provides some insight into history of sea level rise on this island (Monroe, 1980). This terrace was cut by wave action probably during the interglacial period when sea level was 80 m higher than it is today (Monroe, 1980). In Aguadilla (located in northwestern corner) other terraces are found at lower altitudes, many at 40-50 m and 10 m above sea level (Monroe, 1980). Also, along the northern coast there are extensive vestiges of an ancient beach 4 m above the current sea level (Monroe, 1980).
Because geoscientists can date the age of the organic matter within these terraces, one can come to a more accurate date of when these terraces actually formed (as was done in with the Barbados terraces). For recent data and figures on marine terrace dating in the north and south Caribbean and Papua New Guinea see this website Patterns of Sea Level Change. Figure from http://capp.water.usgs.gov/gwa/ch_n/gif/N067.gif. |
