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| | RORAIMA, Formation (Site not responding. Last check: 2007-10-22) |
 | | In turn, the Roraima sediments have been exposed to erosion during the whole Tertiary and in many localities during the Quaternary, being a source of sediments for the geosynclines located to the north and northeast. |
 | | Thus, the continental extension of the Roraima (including the so-called San José sandstone in the Colombian plains) from west to east, covers approximately from 74° W (La Macarena, Colombia), in the Andean foothills, to 54° W (Tafelberg, Surinam). |
 | | Unfortunately, the upper contact (probably with Roraima) and lower contact (probably with a granodiorite of the basement complex) of the remaining narrow section of schists, are concealed by a great ferruginous quartz injection of hydrothermal origin, in which the schists are found scattered as separated masses. |
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