Crustal structure of the high Andes in the North Pampean flat slab segment from magnetic and gravity data. (January 2017)

• Record Type: Journal Article
• Authors: Sánchez, Marcos A.; Winocur, Diego; Álvarez, Orlando; Folguera, Andrés; Martinez, Myriam P.
• Is Part Of: Journal of South American earth sciences. Volume 73(2017:Jan.)
• Page Start: 153
• Page End: 167
• Publication Date: 2017-01
• Subjects: Central Andes -- Aerial magnetic data -- Satellite gravity data -- Terrestrial gravity data -- Paleogene basin architecture -- Paleozoic basement structure; Geology -- Latin America -- Periodicals; Earth sciences -- Latin America -- Periodicals; Geology -- Antarctica -- Periodicals; Earth sciences -- Antarctica -- Periodicals; Geology -- Caribbean Area -- Periodicals; Earth sciences -- Caribbean Area -- Periodicals; Géologie -- Amérique latine -- Périodiques; Sciences de la terre -- Amérique latine -- Périodiques; Géologie -- Antarctique -- Périodiques; Sciences de la terre -- Antarctique -- Périodiques; Géologie -- Caraïbes (Région) -- Périodiques; Sciences de la terre -- Caraïbes (Région) -- Périodiques; Earth sciences; Geology; Antarctica; Caribbean Area; Latin America; Periodicals; 550.5
• DOI: 10.1016/j.jsames.2016.12.007
• Languages: English
• ISSNs: 0895-9811

Abstract

Abstract: The Main Andes at the northern Chilean-Pampean flat slab segment were formed by the inversion of late Oligocene to early Miocene extensional depocenters in Neogene times. Their structure, size and depth are loosely constrained by field data since these sequences have amalgamated forming an almost continuous blanket with scarce basement outcrops. Satellite and aerial gravity and magnetic data are used in this work to define a 3D model that shows the basement structure at depth and adjust 2D structural sections previously based on field data. The results indicate complex basin geometry with depocenters of variable size and depth buried beneath Mesozoic (?)-Paleogene and Neogene sections. Additionally, previously proposed crustal heterogeneities across this orogenic segment are geophysically constrained with a new crustal heterogeneity identified on the basis of a modeled 2D crustal section. We propose hypothetically, that this crustal discontinuity could have played a role in controlling Paleogene extension at the hanging wall of an asymmetric rift basin, explaining the locus and development of the Doña Ana Basin. Finally, this work provides new information about Cenozoic structure and Paleozoic basement architecture, presumably derived from amalgamation history of one of the highest and more inaccessible regions of the Andes. Graphical abstract: Highlights: Gravity inversion to obtain the geometry of the Doña Ana abanico basin. Determination of main Depocenters from the Andes Range to Western Sierras Pampeanas. Remanent Magnetism determination by the Poisson's Theorem. Crustal Structure of the late Oligocene Miocene sequences located on Principal Andes.