Ca. 13 Ma strike-slip deformation in coastal Sonora from a large-scale, en-echelon, brittle-ductile, dextral shear indicator: implications for the evolution of the California rift
The Rancho Nuevo semi-circular structure is a geomorphological structure defined by drainage patterns in coastal Sonora, about 160 km NW of Hermosillo. The structure is about 15 by 30 km, and it is cored by felsic to intermediate plutons (granodiorite, monzogranite, quartz-porphyry) covered by Mioce...
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| Format: | Article |
| Language: | English |
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Universidad Nacional Autónoma de México, Instituto de Geofísica
2014-10-01
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| Series: | Geofísica Internacional |
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| Online Access: | http://revistagi.geofisica.unam.mx/index.php/RGI/article/view/582 |
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| author | David García-Martínez Molina Garza Molina Garza Jaime Roldán Quintana Héctor Mendívil-Quijada |
| author_facet | David García-Martínez Molina Garza Molina Garza Jaime Roldán Quintana Héctor Mendívil-Quijada |
| author_sort | David García-Martínez |
| collection | DOAJ |
| description | The Rancho Nuevo semi-circular structure is a geomorphological structure defined by drainage patterns in coastal Sonora, about 160 km NW of Hermosillo. The structure is about 15 by 30 km, and it is cored by felsic to intermediate plutons (granodiorite, monzogranite, quartz-porphyry) covered by Miocene volcanic rocks. This work is focused on the deformation of the intrusives which cover most of study area.The plutons are a co-magmatic suite dated between 71±1.1 and 67.9±1.0Ma (U-Pb zircon, LA-ICPMS). The most voluminous unit is a granodiorite characterized by conspicuous sigmoidal fractures at the scale of high resolution satellite images, along which rhyolite dikes were emplaced about 13.2 Ma. Magnetic fabric (AMS) and paleomagnetic data were collected from 27 sites in the granodiorite. Magnetic fabrics are weak but well developed, and are characterized by steep foliation planes with strikes that follow the sigmoidal fracture pattern and suggest NE-SW to NW-SE flattening after emplacement. The characteristic magnetization is of dual polarity, but it is dominantly reverse consistent with emplacement during chron C31r. The prevalent magnetization is southwest and moderately steep negative (ten sites), a discordant direction rotated clockwise about 41º±11 with respect to the expected Late Cretaceous reference direction, also indicating gentle southward tilt. There is, however, paleomagnetic evidence suggesting that the structure did not rotate as a rigid body, but it deformed internally instead. These data are interpreted to indicate that the Rancho Nuevo semicircular structure is a largescale, dextral, brittle-ductile shear indicator. The age of the dikes and the fact that they are covered discordantly by rocks assigned to the tuff of San Felipe indicate that northwest, srikeslip, motion of Baja California peninsula (and thus the Pacific plate relative to North America) was accommodated by faults in coastal Sonora about 13 Ma ago.
doi: https://doi.org/10.1016/S0016-7169(14)70077-7 |
| first_indexed | 2024-04-09T13:48:21Z |
| format | Article |
| id | doaj.art-a8d90a71305140cd8475df098d2dbcba |
| institution | Directory Open Access Journal |
| issn | 0016-7169 2954-436X |
| language | English |
| last_indexed | 2024-04-09T13:48:21Z |
| publishDate | 2014-10-01 |
| publisher | Universidad Nacional Autónoma de México, Instituto de Geofísica |
| record_format | Article |
| series | Geofísica Internacional |
| spelling | doaj.art-a8d90a71305140cd8475df098d2dbcba2023-05-08T21:14:42ZengUniversidad Nacional Autónoma de México, Instituto de GeofísicaGeofísica Internacional0016-71692954-436X2014-10-0153443545610.1016/S0016-7169(14)70077-7582Ca. 13 Ma strike-slip deformation in coastal Sonora from a large-scale, en-echelon, brittle-ductile, dextral shear indicator: implications for the evolution of the California riftDavid García-Martínez0Molina Garza Molina Garza1Jaime Roldán Quintana2Héctor Mendívil-Quijada3Universidad Nacional Autónoma de México, Posgrado en Ciencias de la Tierra, sede Hermosillo Boulevard Colosio y Madrid, s/n 83000, Col. Centro Hermosillo, Sonora, México Sonora, MéxicoUniversidad Nacional Autónoma de México, Centro de Geociencias Campus Juriquilla, 76230 Querétaro, MéxicoUniversidad Nacional Autónoma de México, Posgrado en Ciencias de la Tierra, sede Hermosillo Boulevard Colosio y Madrid, s/n 83000, Col. Centro Hermosillo, Sonora, México Sonora, MéxicoUniversidad Nacional Autónoma de México, Posgrado en Ciencias de la Tierra, sede Hermosillo Boulevard Colosio y Madrid, s/n 83000, Col. Centro Hermosillo, Sonora, México Sonora, MéxicoThe Rancho Nuevo semi-circular structure is a geomorphological structure defined by drainage patterns in coastal Sonora, about 160 km NW of Hermosillo. The structure is about 15 by 30 km, and it is cored by felsic to intermediate plutons (granodiorite, monzogranite, quartz-porphyry) covered by Miocene volcanic rocks. This work is focused on the deformation of the intrusives which cover most of study area.The plutons are a co-magmatic suite dated between 71±1.1 and 67.9±1.0Ma (U-Pb zircon, LA-ICPMS). The most voluminous unit is a granodiorite characterized by conspicuous sigmoidal fractures at the scale of high resolution satellite images, along which rhyolite dikes were emplaced about 13.2 Ma. Magnetic fabric (AMS) and paleomagnetic data were collected from 27 sites in the granodiorite. Magnetic fabrics are weak but well developed, and are characterized by steep foliation planes with strikes that follow the sigmoidal fracture pattern and suggest NE-SW to NW-SE flattening after emplacement. The characteristic magnetization is of dual polarity, but it is dominantly reverse consistent with emplacement during chron C31r. The prevalent magnetization is southwest and moderately steep negative (ten sites), a discordant direction rotated clockwise about 41º±11 with respect to the expected Late Cretaceous reference direction, also indicating gentle southward tilt. There is, however, paleomagnetic evidence suggesting that the structure did not rotate as a rigid body, but it deformed internally instead. These data are interpreted to indicate that the Rancho Nuevo semicircular structure is a largescale, dextral, brittle-ductile shear indicator. The age of the dikes and the fact that they are covered discordantly by rocks assigned to the tuff of San Felipe indicate that northwest, srikeslip, motion of Baja California peninsula (and thus the Pacific plate relative to North America) was accommodated by faults in coastal Sonora about 13 Ma ago. doi: https://doi.org/10.1016/S0016-7169(14)70077-7http://revistagi.geofisica.unam.mx/index.php/RGI/article/view/582miocenegulf of californiasonorastrike-slippaleomagnetism |
| spellingShingle | David García-Martínez Molina Garza Molina Garza Jaime Roldán Quintana Héctor Mendívil-Quijada Ca. 13 Ma strike-slip deformation in coastal Sonora from a large-scale, en-echelon, brittle-ductile, dextral shear indicator: implications for the evolution of the California rift Geofísica Internacional miocene gulf of california sonora strike-slip paleomagnetism |
| title | Ca. 13 Ma strike-slip deformation in coastal Sonora from a large-scale, en-echelon, brittle-ductile, dextral shear indicator: implications for the evolution of the California rift |
| title_full | Ca. 13 Ma strike-slip deformation in coastal Sonora from a large-scale, en-echelon, brittle-ductile, dextral shear indicator: implications for the evolution of the California rift |
| title_fullStr | Ca. 13 Ma strike-slip deformation in coastal Sonora from a large-scale, en-echelon, brittle-ductile, dextral shear indicator: implications for the evolution of the California rift |
| title_full_unstemmed | Ca. 13 Ma strike-slip deformation in coastal Sonora from a large-scale, en-echelon, brittle-ductile, dextral shear indicator: implications for the evolution of the California rift |
| title_short | Ca. 13 Ma strike-slip deformation in coastal Sonora from a large-scale, en-echelon, brittle-ductile, dextral shear indicator: implications for the evolution of the California rift |
| title_sort | ca 13 ma strike slip deformation in coastal sonora from a large scale en echelon brittle ductile dextral shear indicator implications for the evolution of the california rift |
| topic | miocene gulf of california sonora strike-slip paleomagnetism |
| url | http://revistagi.geofisica.unam.mx/index.php/RGI/article/view/582 |
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