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STRUCTURAL GEOLOGY OF NORTH AMERICA 



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REPISA OCCIDENTAL 



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ESTRATIGRAFIA COMPARADA 



DE LA SECCION MESOZOICA 

 EN EL 

 NOROESTE DEL PERU 



Fig. 34.3. Comparative sections of the Meso- 

 zoic of northwestern Peru. Reproduced from 

 Fischer, 1956. 



Middle Paleozoic to early Mesozoic disturbances may well have contributed 

 to the metamorphism of the present day crystalline rocks, but there are more 

 hiatuses than basic data . . . Some of the orthogneisses probably represent 

 pre-Jurassic intrusions (Jenks, 1956). 



The Mesozoic history of the Andean geosyncline in Peru and Ecuador 

 is in general like that of Chile, and its main stratigraphic elements are 

 described by Fischer (1956) whose illustrations are reproduced as Figs. 

 34.3 and 34.4. The pre-batholithic Mesozoic volcanic rocks extend north- 



ward from Chile into southern Peru but there wedge out against the 

 coast. They reappear in northwestern Peru and Ecuador. The map of 

 Fischer ( Fig. 34.4 ) and the map of the Andes of Peru, Ecuador, Columbia, 

 and Bolivia ( Fig. 34.2 ) , which was taken from the Geologic Map of South 

 America (1950), represent the distribution of the Mesozoic pre-batholithic 

 volcanic rocks (Jenks, 1956). The concept of a volcanic archipelago and 

 eugeosyncline on the ocean side (west), and then the miogeosyncline on 



