Stratigraphy and structure of the Altar basin of NW Sonora: Implications for the history of the Colorado River delta and the Salton trough
The Altar basin in northwestern Sonora, Mexico, is a subsidiary basin forming a now inactive part of the Colorado River delta. Its sedimentary record illustrates how the delta prograded in the last 4–5 Ma over a late Miocene, structurally distinct, marine basin at the northern end of the Gulf of Ca...
Saved in:
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Universidad Nacional Autónoma de México
2018-02-01
|
| Series: | Revista Mexicana de Ciencias Geológicas |
| Subjects: | |
| Online Access: | https://rmcg.unam.mx/index.php/rmcg/article/view/762 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1849336831623036928 |
|---|---|
| author | Martín Pacheco Arturo Martín-Barajas Wilfred Elders Juan Manuel Espinosa-Cardeña Javier Helenes Alberto Segura |
| author_facet | Martín Pacheco Arturo Martín-Barajas Wilfred Elders Juan Manuel Espinosa-Cardeña Javier Helenes Alberto Segura |
| author_sort | Martín Pacheco |
| collection | DOAJ |
| description |
The Altar basin in northwestern Sonora, Mexico, is a subsidiary basin forming a now inactive part of the Colorado River delta. Its sedimentary record illustrates how the delta prograded in the last 4–5 Ma 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 lines of Petróleos Mexicanos (PEMEX), and magnetic and gravity surveys from various sources indicates the existence of three sedimentary sequences, A, B, and C, which can be correlated at regional scale and have a thickness >5 km at the basin depocenter. The lower sedimentary sequence A is a shale unit representing open marine conditions (outer neritic). It grades into a thick sequence of interstratified mudstone, siltstone, and sandstone (sequence B), which grades in turn into poorly consolidated sand (sequence C). Extensive outcrops of a sandy, cut and fill succession exposed along the coast of Sonora are 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 along a top-to-the-northwest detachment fault. The Altar basin became inactive as result of the westward shift in the locus of tectonic activity from the Altar fault to the Cerro Prieto fault, coupled with realignments in the course of the Colorado River during Pleistocene time.
|
| format | Article |
| id | doaj-art-ef92dccfc1fe4bd1abbfcfc26ff39cf8 |
| institution | Kabale University |
| issn | 1026-8774 2007-2902 |
| language | English |
| publishDate | 2018-02-01 |
| publisher | Universidad Nacional Autónoma de México |
| record_format | Article |
| series | Revista Mexicana de Ciencias Geológicas |
| spelling | doaj-art-ef92dccfc1fe4bd1abbfcfc26ff39cf82025-08-20T03:44:53ZengUniversidad Nacional Autónoma de MéxicoRevista Mexicana de Ciencias Geológicas1026-87742007-29022018-02-01231Stratigraphy and structure of the Altar basin of NW Sonora: Implications for the history of the Colorado River delta and the Salton troughMartín Pacheco0Arturo Martín-Barajas1Wilfred Elders2Juan Manuel Espinosa-Cardeña3Javier Helenes4Alberto Segura5División de Ciencias de la Tierra, CICESE, Km 107 Carr. Tijuana-Ensenada, Ensenada, Baja California, Mexico.División de Ciencias de la Tierra, CICESE, Km 107 Carr. Tijuana-Ensenada, Ensenada, Baja California, Mexico.Department of Earth Sciences, University of California, Riverside, CA 92521, USADivisión de Ciencias de la Tierra, CICESE, Km 107 Carr. Tijuana-Ensenada, Ensenada, Baja California, Mexico.División de Ciencias de la Tierra, CICESE, Km 107 Carr. Tijuana-Ensenada, Ensenada, Baja California, Mexico.Activo Regional de Exploración, Región Norte, PEMEX, Poza Rica, Veracruz, Mexico. The Altar basin in northwestern Sonora, Mexico, is a subsidiary basin forming a now inactive part of the Colorado River delta. Its sedimentary record illustrates how the delta prograded in the last 4–5 Ma 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 lines of Petróleos Mexicanos (PEMEX), and magnetic and gravity surveys from various sources indicates the existence of three sedimentary sequences, A, B, and C, which can be correlated at regional scale and have a thickness >5 km at the basin depocenter. The lower sedimentary sequence A is a shale unit representing open marine conditions (outer neritic). It grades into a thick sequence of interstratified mudstone, siltstone, and sandstone (sequence B), which grades in turn into poorly consolidated sand (sequence C). Extensive outcrops of a sandy, cut and fill succession exposed along the coast of Sonora are 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 along a top-to-the-northwest detachment fault. The Altar basin became inactive as result of the westward shift in the locus of tectonic activity from the Altar fault to the Cerro Prieto fault, coupled with realignments in the course of the Colorado River during Pleistocene time. https://rmcg.unam.mx/index.php/rmcg/article/view/762stratigraphy, rifting, Colorado River delta, Altar basin, Gulf of California.estratigrafía, rifting, delta del Río Colorado, Cuenca de Altar, Golfo de California. |
| spellingShingle | Martín Pacheco Arturo Martín-Barajas Wilfred Elders Juan Manuel Espinosa-Cardeña Javier Helenes Alberto Segura Stratigraphy and structure of the Altar basin of NW Sonora: Implications for the history of the Colorado River delta and the Salton trough Revista Mexicana de Ciencias Geológicas stratigraphy, rifting, Colorado River delta, Altar basin, Gulf of California. estratigrafía, rifting, delta del Río Colorado, Cuenca de Altar, Golfo de California. |
| title | Stratigraphy and structure of the Altar basin of NW Sonora: Implications for the history of the Colorado River delta and the Salton trough |
| title_full | Stratigraphy and structure of the Altar basin of NW Sonora: Implications for the history of the Colorado River delta and the Salton trough |
| title_fullStr | Stratigraphy and structure of the Altar basin of NW Sonora: Implications for the history of the Colorado River delta and the Salton trough |
| title_full_unstemmed | Stratigraphy and structure of the Altar basin of NW Sonora: Implications for the history of the Colorado River delta and the Salton trough |
| title_short | Stratigraphy and structure of the Altar basin of NW Sonora: Implications for the history of the Colorado River delta and the Salton trough |
| title_sort | stratigraphy and structure of the altar basin of nw sonora implications for the history of the colorado river delta and the salton trough |
| topic | stratigraphy, rifting, Colorado River delta, Altar basin, Gulf of California. estratigrafía, rifting, delta del Río Colorado, Cuenca de Altar, Golfo de California. |
| url | https://rmcg.unam.mx/index.php/rmcg/article/view/762 |
| work_keys_str_mv | AT martinpacheco stratigraphyandstructureofthealtarbasinofnwsonoraimplicationsforthehistoryofthecoloradoriverdeltaandthesaltontrough AT arturomartinbarajas stratigraphyandstructureofthealtarbasinofnwsonoraimplicationsforthehistoryofthecoloradoriverdeltaandthesaltontrough AT wilfredelders stratigraphyandstructureofthealtarbasinofnwsonoraimplicationsforthehistoryofthecoloradoriverdeltaandthesaltontrough AT juanmanuelespinosacardena stratigraphyandstructureofthealtarbasinofnwsonoraimplicationsforthehistoryofthecoloradoriverdeltaandthesaltontrough AT javierhelenes stratigraphyandstructureofthealtarbasinofnwsonoraimplicationsforthehistoryofthecoloradoriverdeltaandthesaltontrough AT albertosegura stratigraphyandstructureofthealtarbasinofnwsonoraimplicationsforthehistoryofthecoloradoriverdeltaandthesaltontrough |