Mid-Tertiary isopach and lithofacies maps for the Los Angeles region, California: Templates for palinspastic reconstruction to 17.4 Ma

McCulloh, Thane H.; Beyer, Larry A.

doi:10.3133/pp1690

Cited by 5 publications

(6 citation statements)

References 53 publications

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“…Evidence cited by Campbell and Yerkes [1976] indicates that intrusive igneous rocks, which are correlative with the Conejo Volcanics, postdate and seal the low‐angle faults within the Malibu coast allochthons. The oldest reliably dated unit in the Conejo Volcanics is 15.9 ± 0.8 Ma [ McCulloh and Beyer , 2004]. A large region underwent uniform rotation, given that the Conejo rotation in the western part of the mountains is identical to the result from the allochthonous Piuma Member of the Sespe Formation (77° ± 7°).…”

Section: Discussionmentioning

confidence: 99%

“…Paleomagnetically determined rotation angle is indicated by partial circle; fan denotes 95% confidence limit of rotation. Geologic map sources are as follows: Vaqueros and Sespe Formations [McCulloh and Beyer, 2004], Conejo Volcanics [Kamerling and Luyendyk, 1979], and thrust faults [Campbell et al, 1966]. et al [2008] published paleomagnetic results from essentially the same stratigraphic interval along Piuma Road.…”

Section: Methodsmentioning

confidence: 99%

“…As the Pacific‐Farallon ridge system began to impinge on southwestern North America, the long‐lived fore‐arc regime was disrupted by large‐scale rifting [ Wilson et al , 2005]. The WTRB may have originally capped crystalline basement rocks now beneath the Los Angeles Basin before the block became detached and was rotated nearly perpendicular to the former arc alignment [ Wright , 1991; Crouch and Suppe , 1993; McCulloh and Beyer , 2004].…”

Section: Introductionmentioning

confidence: 99%

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Clockwise rotation and implications for northward drift of the western Transverse Ranges from paleomagnetism of the Piuma Member, Sespe Formation, near Malibu, California

Hillhouse

2010

Geochem Geophys Geosyst

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New paleomagnetic results from mid‐Tertiary sedimentary beds in the Santa Monica Mountains reinforce the evidence for large‐scale rotation of the western Transverse Ranges, and anisotropy measurements indicate that compaction‐induced inclination flattening may resolve a long‐standing controversy regarding the original paleolatitude of the rotated block. Previously published paleomagnetic data indicate that post‐Oligocene rotation amounts to 70°–110° clockwise, affecting the Channel Islands, Santa Monica Mountains, and Santa Ynez Mountains. The Sespe Formation near Malibu consists of a lower member dominated by nonmarine sandstone and conglomerate and an upper section, the Piuma Member, which consists of gray‐red sandstone and mudstone interbedded with minor tuff and limestone beds. The Piuma Member has a paleomagnetic pole at 36.6°N, 326.7°E (A95min = 5.0°, A95max = 9.6°), obtained by thermal demagnetization of 34 oriented cores from Oligocene and early Miocene beds. After correcting for plunge of the geologic structure, the data are consistent with significant clockwise rotation (77° ± 7°) of the region relative to stable North America. Rotation of the western Transverse Ranges is generally viewed as a consequence of Pacific–North American plate interactions after 28 Ma, when east–west subduction gave way to northwest transform motion in southern California. Inclinations from the Piuma study indicate a paleolatitude anomaly of 11° ± 7° and are consistent with a mean northward drift that exceeds generally accepted San Andreas fault displacement by a factor of 3. However, sedimentary inclination error may accentuate the anomaly. Anisotropy of isothermal remanent magnetization indicates inclination flattening of approximately 8°, and correction for the effect reduces the paleolatitude anomaly to 5.3° ± 5.8°. Compaction may explain the inclination flattening in these sedimentary rocks, but the process does not adequately explain lower‐than‐expected inclinations found in previous studies of Miocene volcanic rocks of the western Transverse Ranges.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Clockwise rotation and implications for northward drift of the western Transverse Ranges from paleomagnetism of the Piuma Member, Sespe Formation, near Malibu, California

Hillhouse

2010

Geochem Geophys Geosyst

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“…Because the three members of the Topanga Formation in the Santa Ana 30'x 60' quadrangle, have not been correlated with the Topanga Group formations recognized by Yerkes and Campbell (1979) he chose to retain the nomenclature of the source maps for the Santa Ana quadrangle. - McCulloh and Beyer (2004) use formation nomenclature of various authors in different localities, and do not discuss the Topanga Group as a stratigraphic unit.…”

Section: Chronology Of Usagementioning

confidence: 99%

The Miocene Topanga group of southern California — A 100-year history of changes in stratigraphic nomenclature

Campbell¹,

McCulloh²,

Vedder³

2007

Open-File Report

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“…However, the pre-middle Miocene positions of individual fault blocks have not been comprehensively established. Partial reconstructions using extensive subsurface data, precise age dating, and well-established minimum fault movements and rotations have demonstrated the difficulty in accurately modeling the early Miocene margin of the North American continent (McCulloh and Beyer, 2004).…”

Section: The Transverse Ranges and The San Andreas Faultmentioning

confidence: 99%

Preliminary geologic map of the Los Angeles 30' x 60' quadrangle, Southern California

Yerkes¹,

Campbell²,

Alvarez³

et al. 2005

Open-File Report

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A geologic-mapping project sponsored jointly by the U.S. Geological Survey and the California Geological Survey San Bernardino 30' x 60' quadrangle (Morton and Miller, 2003), which adjoins the Los Angeles sheet on the east. The modified nomenclature results in some local generalizations of the map. In addition, the Quaternary surficial deposits have been relabeled according to standardized SCAMP nomenclature where data permit. The bedrock units of the area are commonly described in two principal groups: 1) Basement rocks-early Cretaceous and older, crystalline metamorphic and igneous rocks; and 2) The superjacent sequence of late Cretaceous and Tertiary strata. The greatest contrast in basement character is at the boundaries of the San Gabriel Mountains-Soledad Basin block. The San Gabriel Mountains form a basement massif that includes components of Proterozoic, Paleozoic, and pre-middle-Cretaceous Mesozoic metamorphic and plutonic rocks. These are the oldest basement rocks in the Los Angeles quadrangle and appear to represent old continental crust at the western margin of the North American craton, and which has been thrust over Jurassic oceanic crust of a different metamorphic facies than is found in adjacent blocks. In the eastern Los Angeles Basin, to the south of the San Gabriel Mountains, and in the Santa Monica Mountains, to the west of the San Gabriel Mountains, the basement rocks are metasedimentary and metavolcanic rocks of Jurassic age, that were probably deposited on a Jurassic oceanic crust, and accreted to the margin of the North American craton; they have been intruded by early Cretaceous granitic bodies of the same age as similar rocks in the San Gabriel Mountains, but the closeness of their relationship is not clear. The basement rocks of the western Los Angeles Basin also are associated with a Jurassic oceanic crust; however, their metamorphic character is significantly different, including blueschist facies schists that represent metamorphism in a subduction zone. The basement in the Topatopa Mountains block is unknown, but in the Santa Ynez Mountains, a few miles to the west, the basement is Franciscan Formation, including schists very much like those of the western Los Angeles Basin basement rocks. The superjacent sequence consists of Upper Cretaceous and Tertiary sedimentary and volcanic strata that rest unconformably on the crystalline basement. The regional unconformity at the base of the Upper Cretaceous is expressed only in the central Santa Monica Mountains, where the Trabuco Formation overlies basement rocks. Another regional unconformity, at the base of the Paleogene section, can be seen in the western Santa Monica Mountains and the Simi Hills where the Simi Conglomerate overlies the Upper Cretaceous sequence. The middle Miocene disruption of the pre-middle Miocene sequence and the formation of more localized basins is expressed by more restricted unconformities at the bases of latemiddle Miocene and younger strata and extreme variations in thickness of late Miocene and younger units....

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Mid-Tertiary isopach and lithofacies maps for the Los Angeles region, California: Templates for palinspastic reconstruction to 17.4 Ma

Cited by 5 publications

References 53 publications

Clockwise rotation and implications for northward drift of the western Transverse Ranges from paleomagnetism of the Piuma Member, Sespe Formation, near Malibu, California

Clockwise rotation and implications for northward drift of the western Transverse Ranges from paleomagnetism of the Piuma Member, Sespe Formation, near Malibu, California

The Miocene Topanga group of southern California — A 100-year history of changes in stratigraphic nomenclature

Preliminary geologic map of the Los Angeles 30' x 60' quadrangle, Southern California

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