Crustal structure and location of the Ouachita orogenic belt in northern Mexico

Moreno, F. A.; Mickus, K. L.; Keller, Randy

Instituto de Geofísica, UNAM, publicado en Geofísica Internacional, y cosechado de Revistas UNAM

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Instituto de Geofísica, UNAM
Revistas UNAM. Dirección General de Publicaciones y Fomento Editorial, UNAM en


Moreno, F. A., et al. (2000). Crustal structure and location of the Ouachita orogenic belt in northern Mexico. Geofísica Internacional; Vol. 39 No. 3, 2000. Recuperado de

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Moreno, F. A.; Mickus, K. L.; Keller, Randy
Artículo de Investigación
Área del conocimiento
Físico Matemáticas y Ciencias de la Tierra
Crustal structure and location of the Ouachita orogenic belt in northern Mexico
The location of the Paleozoic southern margin of Laurentia in Mexico has been much debated. Determining its location isimportant for the evaluation of hypotheses that suggest large pieces of southwestern North America were translated toward SouthAmerica during the breakup of Laurentia (early Cambrian) and Pangea (early Mesozoic) and that there were large lateral movementsin northern Mexico in Mesozoic time that displaced the Ouachita orogenic belt. Using limited Paleozoic outcrops, leadisotopic data, regional seismic data and regional gravity anomalies, we show that the Ouachita orogenic belt and the Laurentianmargin in Mexico trend either directly south into Coahuila or south-southwest across Chihuahua toward Durango from the BigBend region of west Texas. In order to evaluate these two possibilities, integrated crustal models were constructed along threeprofiles in northern Mexico and west Texas. Because constraints on deep structure are sparse, each profile could be modeled witheither a southward or a south-southwestward extension of the Ouachita orogenic belt. The southward extension model suggeststhat two regional gravity minima delineate a Paleozoic foreland basin (Mapimi basin) along the Chihuahua/Coahuila border, andan accreted terrane (Coahuila terrane) in western Coahuila. The south-southwestward extension model suggests that these gravityminima both delineate accreted terranes. We favor a south-southwestward extension because we can trace the gravity maximumassociated with the known Ouachita interior zone 300 km into eastern Chihuahua and south toward Durango in a way that isconsistent with trends in lead isotopic data, pre-Mesozoic geologic data from drill holes and outcrops, and Ouachita-style lithologiesand structures found in western Sonora. Spanning the gap between the postulated Ouachita orogenic belt in southern Chihuahuawith possible similar lithologies in Sonora with a northwest-trending margin provides a simple way to complete our picture ofthe southern portion of Laurentia during the early Paleozoic.
Paleozoico; gravimetría; isótopos de plomo; México; la faja orogénica de Ouachita.; Paleozoic; gravity anomalies; Pb isotopes; Mexico; Ouachita orogenic belt.