scholarly journals Early Pliocene Marine Transgression into the Lower Colorado River Valley, Southwestern USA, by Re-Flooding of a Former Tidal Strait

2021 ◽  
Author(s):  
Rebecca Dorsey ◽  
Juan Carlos Braga Alarcón ◽  
Kevin Gardner ◽  
Brennan O'Connell
Keyword(s):  
Gulf Of California ◽  
Colorado River ◽  
Large River ◽  
River Valley ◽  
Marine Waters ◽  
Shallow Marine ◽  
Wide Range ◽  
Regional Tectonic ◽  
Southwestern Usa ◽  
Lower Colorado River

Marine straits and seaways are known to host a wide range of sedimentary processes and products, but the role of marine connections in the development of large river systems remains little studied. This study explores a hypothesis that shallow marine waters flooded the lower Colorado River valley at ~ 5 Ma along a fault-controlled former tidal straight, soon after the river was first integrated to the northern Gulf of California. The upper bioclastic member of the southern Bouse Formation provides a critical test of this hypothesis. The upper bioclastic member contains wave ripple-laminated bioclastic grainstone with minor red mudstone, pebbly grainstone with HCS-like stratification and symmetrical gravelly ripples, and calcareous-matrix conglomerate. Fossils include upward-branching segmented coralline-like red algae with no known modern relatives but confirmed as marine calcareous algae, echinoid spines, barnacles, shallow marine foraminifers, clams, and serpulid worm tubes. These results provide evidence for deposition in a shallow marine bay or estuary seaward of the transgressive backstepping Colorado River delta. Tsunamis generated by seismic and meteorologic sources likely produced the HCS-like and wave-ripple cross-bedding in poorly-sorted gravelly grainstone. Marine waters inundated a former tidal strait within a fault-bounded tectonic lowland that connected the lower Colorado River to the Gulf of California. Delta backstepping and transgression resulted from a decrease in sediment output due to sediment trapping in upstream basins and relative sea-level rise produced by regional tectonic subsidence.

scholarly journals Early Pliocene Marine Transgression into the Lower Colorado River Valley, Southwestern USA, by Re-Flooding of a Former Tidal Strait

2021 ◽  
pp. SP523-2021-57
Author(s):  
Rebecca J. Dorsey ◽  
Juan Carlos Braga ◽  
Kevin Gardner ◽  
Kristin McDougall ◽  
Brennan O'Connell
Keyword(s):  
Gulf Of California ◽  
Colorado River ◽  
Large River ◽  
River Valley ◽  
Marine Waters ◽  
Content Type ◽  
Shallow Marine ◽  
Wide Range ◽  
Supplementary Material ◽  
Lower Colorado River

AbstractMarine straits and seaways are known to host a wide range of sedimentary processes and products, but the role of marine connections in the development of large river systems remains little studied. This study explores a hypothesis that shallow marine waters flooded the lower Colorado River valley at ∼ 5 Ma along a fault-controlled former tidal straight, soon after the river was first integrated to the northern Gulf of California. The upper bioclastic member of the southern Bouse Formation provides a critical test of this hypothesis. The upper bioclastic member contains wave ripple-laminated bioclastic grainstone with minor red mudstone, pebbly grainstone with HCS-like stratification and symmetrical gravelly ripples, and calcareous-matrix conglomerate. Fossils include upward-branching segmented coralline-like red algae with no known modern relatives but confirmed as marine calcareous algae, echinoid spines, barnacles, shallow marine foraminifers, clams, and serpulid worm tubes. These results provide evidence for deposition in a shallow marine bay or estuary seaward of the transgressive backstepping Colorado River delta. Tsunamis generated by seismic and meteorologic sources likely produced the HCS-like and wave-ripple cross-bedding in poorly-sorted gravelly grainstone. Marine waters inundated a former tidal strait within a fault-bounded tectonic lowland that connected the lower Colorado River to the Gulf of California. Delta backstepping and transgression resulted from a decrease in sediment output due to sediment trapping in upstream basins and relative sea-level rise produced by regional tectonic subsidence.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5740426

scholarly journals Review and analysis of the age and origin of the Pliocene Bouse Formation, lower Colorado River Valley, southwestern USA

Geosphere ◽  
2013 ◽  
Vol 9 (3) ◽  
pp. 444-459 ◽  
Author(s):  
Jon E. Spencer ◽  
P. Jonathan Patchett ◽  
Philip A. Pearthree ◽  
P. Kyle House ◽  
Andrei M. Sarna-Wojcicki ◽  
...  
Keyword(s):  
Colorado River ◽  
River Valley ◽  
Southwestern Usa ◽  
Lower Colorado River

scholarly journals Tectonostratigraphic record of late Miocene–early Pliocene transtensional faulting in the Eastern California shear zone, southwestern USA

Geosphere ◽  
2021 ◽  
Author(s):  
Rebecca J. Dorsey ◽  
Brennan O’Connell ◽  
Kevin K. Gardner ◽  
Mindy B. Homan ◽  
Scott E.K. Bennett ◽  
...  
Keyword(s):  
North America ◽  
Shear Zone ◽  
Gulf Of California ◽  
Colorado River ◽  
Normal Fault ◽  
River Valley ◽  
Plate Motion ◽  
Fault System ◽  
Eastern California Shear Zone ◽  
Southwestern Usa

The Eastern California shear zone (ECSZ; southwestern USA) accommodates ~20%–25% of Pacific–North America relative plate motion east of the San Andreas fault, yet little is known about its early tectonic evolution. This paper presents a detailed stratigraphic and structural analysis of the uppermost Miocene to lower Pliocene Bouse Formation in the southern Blythe Basin, lower Colorado River valley, where gently dipping and faulted strata provide a record of deformation in the paleo-ECSZ. In the western Trigo Mountains, splaying strands of the Lost Trigo fault zone include a west-dipping normal fault that cuts the Bouse Formation and a steeply NE-dipping oblique dextral-normal fault where an anomalously thick (~140 m) section of Bouse Formation siliciclastic deposits filled a local fault-controlled depocenter. Systematic basinward thickening and stratal wedge geometries in the western Trigo and southeastern Palo Verde Mountains, on opposite sides of the Colorado River valley, record basinward tilting during deposition of the Bouse Formation. We conclude that the southern Blythe Basin formed as a broad transtensional sag basin in a diffuse releasing stepover between the dextral Laguna fault system in the south and the Cibola and Big Maria fault zones in the north. A palinspastic reconstruction at 5 Ma shows that the southern Blythe Basin was part of a diffuse regional network of linked right-step­ping dextral, normal, and oblique-slip faults related to Pacific–North America plate boundary dextral shear. Diffuse transtensional strain linked northward to the Stateline fault system, eastern Garlock fault, and Walker Lane, and southward to the Gulf of California shear zone, which initiated ca. 7–9 Ma, implying a similar age of inception for the paleo-ECSZ.

A History of Date Palms in the Lower Colorado River Valley

2019 ◽  
Vol 61 (4) ◽  
pp. 863-879
Author(s):  
Dennis V. Johnson ◽  
Jane C. MacKnight
Keyword(s):  
Colorado River ◽  
River Valley ◽  
Date Palms ◽  
History Of ◽  
Lower Colorado River

scholarly journals Post–12 Ma deformation in the lower Colorado River corridor, southwestern USA: Implications for diffuse transtension and the Bouse Formation

Geosphere ◽  
2019 ◽  
Vol 16 (1) ◽  
pp. 111-135
Author(s):  
Jacob O. Thacker ◽  
Karl E. Karlstrom ◽  
Laura J. Crossey ◽  
Ryan S. Crow ◽  
Colleen E. Cassidy ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Colorado River ◽  
San Andreas ◽  
History Of ◽  
Southwestern Usa ◽  
First Arrival ◽  
Metamorphic Core ◽  
East West ◽  
River Corridor ◽  
Lower Colorado River

Abstract Structural evidence presented here documents that deformation was ongoing within the lower Colorado River corridor (southwestern USA) during and after the latest Miocene Epoch, postdating large-magnitude extension and metamorphic core complex formation. Geometric and kinematic data collected on faults in key geologic units constrain the timing of deformation in relation to the age of the Bouse Formation, a unit that records the first arrival and integration of the Colorado River. North-south–striking extensional, NW-SE–striking oblique dextral, NE-SW–striking oblique sinistral, and east-west–striking contractional faults and related structures are observed to deform pre– (>6 Ma), syn– (6–4.8 Ma), and post–Bouse Formation (<4.8 Ma) strata. Fault displacements are typically at the centimeter to meter scale, and locally exhibit 10-m-scale displacements. Bouse Formation basalt carbonate locally exhibits outcrop-scale (tens of meters) syndepositional dips of 30°–90°, draped over and encrusted upon paleotopography, and has a basin-wide vertical distribution of as much as 500 m. We argue that part of this vertical distribution of Bouse Formation deposits represents syn- and post-Bouse deformation that enhanced north-south–trending depocenters due to combined tectonic and isostatic subsidence in a regional fault kinematic framework of east-west diffuse extension within an overall strain field of dextral transtension. Here we (1) characterize post-detachment tectonism within the corridor, (2) show that diffuse tectonism is cumulatively significant and likely modified original elevations of Bouse Formation outcrops, and (3) demonstrate that this tectonism may have played a role in the integration history of the lower Colorado River. We suggest a model whereby intracontinental transtension took place in a several hundred kilometers-wide area inboard of the San Andreas fault within a diffuse Pacific–North America plate margin since the latest Miocene.

The Archaeological Delineation of a Cultural Boundary in Papagueria

1955 ◽  
Vol 20 (4Part1) ◽  
pp. 367-374 ◽  
Author(s):  
Paul H. Ezell
Keyword(s):  
Gulf Of California ◽  
Colorado River ◽  
River Valley ◽  
Historical Sources ◽  
Gila River ◽  
The North ◽  
Ethnic Boundary ◽  
Cultural Boundary ◽  
Imaginary Line ◽  
River Valleys

The area dealt with in this report is that portion of northwestern Sonora and southwestern Arizona bounded on the southwest by the Gulf of California, on the west by the Colorado River valley below the junction of the Gila River, on the north by the Gila River valley, and on the east by an imaginary line from the vicinity of Gila Bend south along the western edge of the Papago Reservation and thence southwest to the mouth of the Sonoyta River on the Gulf of California (Fig. 106). Within this area Sauer has suggested a boundary between the Piman-speaking people of southern Arizona and northern Sonora, and the Yuman-speaking tribes of the lower Colorado and Gila River valleys, based on linguistic affiliations described in early historical sources (Sauer 1934, map). On archaeological evidence Gifford has suggested that the locality between Punta La Cholla and the mouth of the Sonoyta River represented a point on an ethnic boundary (Gifford 1946: 221).

Seasonal Habitat Selection by Birds in the Lower Colorado River Valley

Ecology ◽  
1980 ◽  
Vol 61 (6) ◽  
pp. 1402-1411 ◽  
Author(s):  
Jake Rice ◽  
Bertin W. Anderson ◽  
Robert D. Ohmart
Keyword(s):  
Habitat Selection ◽  
Colorado River ◽  
River Valley ◽  
Lower Colorado River
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