Recognition on space photographs of structural elements of Baja California

Hamilton, Warren

doi:10.3133/pp718

Cited by 18 publications

(12 citation statements)

References 6 publications

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“…At the latitude of the study area, the escarpment is formed by the curviplanar San Pedro Mártir fault, a NNW striking listric normal fault with a strike length of ∼100 km (Figures 1 and 2). The fault accommodates up to ∼5 km of east down displacement [ Hamilton , 1971; Gastil et al , 1975], but slip decreases systematically toward the northern and southern fault tip. Stratigraphic relationships indicate that fault slip initiated between ∼12.6 Ma and ∼6 Ma [ Stock , 1989], and Late Quaternary fault scarps suggest recent or ongoing activity on the breakaway fault [ Brown , 1978].…”

Section: Regional Geological and Tectonic Settingmentioning

confidence: 99%

Low‐temperature thermochronology of northern Baja California, Mexico: Decoupled slip‐exhumation gradients and delayed onset of oblique rifting across the Gulf of California

et al. 2011

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The northern Gulf Extensional Province displays key structural relationships that characterize the magnitude, direction, and timing of Neogene rift‐related transtension during the opening of the Gulf of California. Apatite fission track and (U‐Th)/He thermochronology from the Sierra San Felipe document moderate cooling (4°C/Myr–7°C/Myr) during the early Paleogene associated with progressive unroofing caused by erosional downwearing of the ancestral Peninsular Ranges. Beginning at ∼45–35 Ma, a period of tectonic quiescence with low cooling rates (≤1°C/Myr) marks the development of a regional Oligocene‐Miocene peneplain. Rift‐related exhumation began at ∼9–7 Ma and attains ∼2.5 km in the hinges of two antiformal megamullions. Decoupling between exhumation and finite displacement in certain fault segments is explained by vertical deflections associated with extension‐perpendicular folding of the fault surfaces. The main faults of the detachment system were active contemporaneously, thus forming a mechanically linked array of large‐displacement normal faults in the hanging wall of the Main Gulf Escarpment. The Late Miocene onset of transtension in the Sierra San Felipe suggests that widespread deformation may only have localized in the Gulf Extensional Province between ∼9 and 7 Ma, some ∼3–5 Ma after a major plate reorganization associated with cessation of subduction in the trench to the west. Between ∼12 Ma and ∼9–7 Ma, plate boundary shearing was likely distributed between the continental borderland west of Baja California and the southern Basin and Range province in Mexico.

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Section: Regional Geological and Tectonic Settingmentioning

confidence: 99%

Low‐temperature thermochronology of northern Baja California, Mexico: Decoupled slip‐exhumation gradients and delayed onset of oblique rifting across the Gulf of California

et al. 2011

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“…Dextral displacement along the Agua Blanca fault, trending west-northwest-east-southeast across half of northern Baja California (Fig. 1A) is evidently absorbed by extensional deformation at the Sierra San Pedro Martir near its eastern end without entering the Gulf of California (Hamilton, 1971;O'Connor and Chase, 1989). The slip transmitted up the length of the gulf is apparently transferred, however, to multiple San Andreas splays (Fig.…”

Section: Gulf Of Californiamentioning

confidence: 99%

Kinematics of Transrotational Tectonism in the California Transverse Ranges and Its Contribution to Cumulative Slip Along the San Andreas Transform Fault System

Dickinson¹

1996

Kinematics of Transrotational Tectonism in the California Transverse Ranges and Its Contribution to Cumulative Slip Along the S

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The evaluation of total tectonic transport across a complex transform fault system of finite width requires taking into account tectonic rotations about vertical axes of crustal blocks within the transform zone. The Luyendyk hypothesis of transrotation, based on paleomagnetic evidence for tectonic rotations within the Transverse Ranges, offers the means to reconcile disparate estimates of San Andreas transform motion based on (1) summation of fault offsets on land, and (2) global analysis of seafloor magnetic anomalies. In recent years, expanded geodetic data and improved global plate circuits have largely resolved the discrepancy for current transform motion rate, but not the discrepancy for cumulative transform slip through time.A coherent kinematic model for transrotational deformation developed in this paper indicates that discrepancies between overall displacements inferred from offsets of geologic features and from worldwide correlation of sea-floor magnetic anomalies can be reconciled for at least the past 16-22 m.y. by allowing explicitly for transrotational effects. All summations of fault displacements within the San Andreas system that do not take the paleomagnetic evidence for transrotation into account are discounted as incomplete. The kinematic model is compatible with a range of dynamic models for transrotation, and does not permit a choice to be made among alternate geodynamic rationales.The kinematic model includes preferred "pinned" and alternate "decoupled" geometric variants, and describes the movements of (1) structural panels bounded by sinistral faults and rotating clockwise, and (2) irrotational sliding blocks bounded by dextral faults subparallel to the San Andreas trend. Geometric expressions are presented for cumulative slip on the rotating sinistral faults and the nonrotating dextral faults, as the sliding blocks move out of the way of the rotating panels, in terms of initial and final angles between the trends of the sinistral and dextral faults, and for the spacings of the faults. The net shear imparted parallel to the transform direction by panel rotation within the shear system can also be calculated. Analysis shows that transpressional and transtensional deformation is the general rule within domains of both rotating panels and sliding blocks associated with transrotation.The application of the kinematic model to tectonic analyses of key geologic provinces yields the following comparative results. (1) Net slip on the array of eastwest sinistral faults in the eastern Transverse Ranges, but not the observed distribution of slip on individual faults of the array, is predicted successfully by calculations.(2) Net slip across northwest-trending dextral faults of the Mojave block is compatible with the transrotational shear imparted by the eastern Transverse Ranges, provided allowance is made for partial transposition of the shear locus through the

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“…On space photographs from hand-held and automatic cameras of Gemini and Apollo missions, he observed corresponding displacements on westward-flowing streams. Hamilton's (1971) observation, however, was contested by Fletcher and Munguia (2000) who did not see a consistent sense of lateral deflection among the abundant drainages. They favored an east-down normal fault interpretation.…”

Section: Discussionmentioning

confidence: 75%

“…1) has caused young brittle transtensile deformation along the southern segment of the fault related to the dextral San Andreas transform motion. Regarding recent regional dextral strike-slip tectonics, it should be noted that Hamilton (1971) identified the El Carrizal fault (''Bahia Concepción-La Paz fault'' of Hamilton 1971), which is easily identified on satellite images and which trends approximately parallel to the La Paz fault (Fig. 1), as a modern dextral strike-slip fault.…”

Section: Discussionmentioning

confidence: 98%

Cretaceous to Cenozoic sequential kinematics in the forearc–arc transition: effects of changing oblique plate convergence and the San Andreas system with implications for the La Paz fault (southern Baja California, Mexico)

Mattern

Venzor

Espinoza

et al. 2008

Int J Earth Sci (Geol Rundsch)

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We studied metasediments and mylonitic arc granitoids from the forearc-arc transition of southern Baja California, Mexico. Thin section analyses and field evidence show that metamorphism of the forearc-arc transition is of the high T/P active margin type. The heat was provided by Cretaceous arc intrusions. Field observations and thin section analyses, including the time/ temperature deformation path, demonstrate that the study area was first affected by dextral, ductile shearing followed by ductile, sinistral, possibly transpressive strike-slip parallel to the magmatic arc during the Cretaceous. Both intervals are related to changing oblique plate convergence and, thus, identified as trench-linked strike-slip effects.

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Recognition on space photographs of structural elements of Baja California

Cited by 18 publications

References 6 publications

Low‐temperature thermochronology of northern Baja California, Mexico: Decoupled slip‐exhumation gradients and delayed onset of oblique rifting across the Gulf of California

Low‐temperature thermochronology of northern Baja California, Mexico: Decoupled slip‐exhumation gradients and delayed onset of oblique rifting across the Gulf of California

Kinematics of Transrotational Tectonism in the California Transverse Ranges and Its Contribution to Cumulative Slip Along the San Andreas Transform Fault System

Cretaceous to Cenozoic sequential kinematics in the forearc–arc transition: effects of changing oblique plate convergence and the San Andreas system with implications for the La Paz fault (southern Baja California, Mexico)

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