Stratigraphy and structure of the Altar basin of NW Sonora: Implications for the history of the Colorado River delta and the Salton trough
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| Format: | Artículo científico |
| Langue: | en |
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Universidad Nacional Autónoma de México
2006
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| _version_ | 1876483708449456128 |
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| author | Martín Pacheco |
| author_facet | Martín Pacheco |
| contents | Stratigraphy and structure of the Altar basin of NW Sonora: Implications for the history of the Colorado River delta and the Salton trough Martín Pacheco Wilfred Elders Javier Helenes Alberto Segura Arturo Martín Barajas Juan Manuel Espinosa Cardeña Ciencias de la Tierra rifting Altar basin stratigraphy Gulf of California Colorado River delta The Altar basin in northwestern Sonora, Mexico, is a subsidiary basin forming a now inactive partof the Colorado River delta. Its sedimentary record illustrates how the delta prograded in the last 45Ma over a late Miocene, structurally distinct, marine basin at the northern end of the Gulf of California.Our interpretation of outcrop data, and data from seven exploratory wells, six analog seismic linesof Petróleos Mexicanos (PEMEX), and magnetic and gravity surveys from various sources indicatesthe existence of three sedimentary sequences, A, B, and C, which can be correlated at regional scaleand have a thickness >5 km at the basin depocenter. The lower sedimentary sequence A is a shale unitrepresenting open marine conditions (outer neritic). It grades into a thick sequence of interstratifi edmudstone, siltstone, and sandstone (sequence B), which grades in turn into poorly consolidated sand(sequence C). Extensive outcrops of a sandy, cut and fi ll succession exposed along the coast of Sonoraare consistent with sequences B and C being the sub-aqueous and the sub-aereal parts of the delta,respectively. A contact at the base of the sequence A, where pre-marine continental deposits are missing,and where the marine sequence overlies crystalline basement, is interpreted as tectonic transport alonga top-to-the-northwest detachment fault. The Altar basin became inactive as result of the westward shiftin the locus of tectonic activity from the Altar fault to the Cerro Prieto fault, coupled with realignmentsin the course of the Colorado River during Pleistocene time. 2006 artículo científico 1026-8774 https://www.redalyc.org/articulo.oa?id=57230101 en http://www.redalyc.org/revista.oa?id=572 Revista Mexicana de Ciencias Geológicas application/pdf Universidad Nacional Autónoma de México Revista Mexicana de Ciencias Geológicas (México) Num.1 Vol.23 |
| format | Artículo científico |
| id | redalyc_57230101 |
| institution | Redalyc |
| language | en |
| publishDate | 2006 |
| publisher | Universidad Nacional Autónoma de México |
| spellingShingle | Stratigraphy and structure of the Altar basin of NW Sonora: Implications for the history of the Colorado River delta and the Salton trough Martín Pacheco Ciencias de la Tierra rifting Altar basin stratigraphy Gulf of California Colorado River delta Stratigraphy and structure of the Altar basin of NW Sonora: Implications for the history of the Colorado River delta and the Salton trough Martín Pacheco Wilfred Elders Javier Helenes Alberto Segura Arturo Martín Barajas Juan Manuel Espinosa Cardeña Ciencias de la Tierra rifting Altar basin stratigraphy Gulf of California Colorado River delta The Altar basin in northwestern Sonora, Mexico, is a subsidiary basin forming a now inactive partof the Colorado River delta. Its sedimentary record illustrates how the delta prograded in the last 45Ma over a late Miocene, structurally distinct, marine basin at the northern end of the Gulf of California.Our interpretation of outcrop data, and data from seven exploratory wells, six analog seismic linesof Petróleos Mexicanos (PEMEX), and magnetic and gravity surveys from various sources indicatesthe existence of three sedimentary sequences, A, B, and C, which can be correlated at regional scaleand have a thickness >5 km at the basin depocenter. The lower sedimentary sequence A is a shale unitrepresenting open marine conditions (outer neritic). It grades into a thick sequence of interstratifi edmudstone, siltstone, and sandstone (sequence B), which grades in turn into poorly consolidated sand(sequence C). Extensive outcrops of a sandy, cut and fi ll succession exposed along the coast of Sonoraare consistent with sequences B and C being the sub-aqueous and the sub-aereal parts of the delta,respectively. A contact at the base of the sequence A, where pre-marine continental deposits are missing,and where the marine sequence overlies crystalline basement, is interpreted as tectonic transport alonga top-to-the-northwest detachment fault. The Altar basin became inactive as result of the westward shiftin the locus of tectonic activity from the Altar fault to the Cerro Prieto fault, coupled with realignmentsin the course of the Colorado River during Pleistocene time. 2006 artículo científico 1026-8774 https://www.redalyc.org/articulo.oa?id=57230101 en http://www.redalyc.org/revista.oa?id=572 Revista Mexicana de Ciencias Geológicas application/pdf Universidad Nacional Autónoma de México Revista Mexicana de Ciencias Geológicas (México) Num.1 Vol.23 |
| title | Stratigraphy and structure of the Altar basin of NW Sonora: Implications for the history of the Colorado River delta and the Salton trough |
| topic | Ciencias de la Tierra rifting Altar basin stratigraphy Gulf of California Colorado River delta |
| url | https://www.redalyc.org/articulo.oa?id=57230101 |