Middle to Late Jurassic tectonic evolution of the Klamath Mountains, California‐Oregon

Harper, Gregory D.; Wright, James E.

doi:10.1029/tc003i007p00759

Cited by 135 publications

(124 citation statements)

References 26 publications

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“…3H) (Schweickert and Cowan, 1975;Ingersoll and Schweickert, 1986). No such collision occurred to the north in the Klamath Mountains, where the Klamath phase of the Nevadan orogeny involved opening and closing of a backarc basin behind the conti nental-margin arc concurrently with collision in the study area (Harper and Wright, 1984;Ingersoll and Schweickert, 1986). As the arcarc collision progressed, a new subduction zone began in what was the backarc of the intra oceanic arc (Fig.…”

Section: Late Jurassic Nevadan Orogenymentioning

confidence: 91%

Phanerozoic Tectonic Evolution of Central California and Environs

Ingersoll

1997

International Geology Review

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The use of actualistic analog models for paleotectonic reconstruction produces significant advances in our understanding of evolutionary continental tectonics. The sequential application of such models is possible in a cross section from the central California coast to Utah. This transect represents one of the best-understood Phanerozoic continental margins on Earth. Excellent exposure, detailed local studies, and regional syntheses all contribute to the choice of appropriate plate-tectonic models for successive intervals from the latest Neoproterozoic to the Quaternary. These models include craton, terrestrial rift, nascent ocean, intraplate continental margin, intraoceanic magmatic arc (both extensional and neutral), continental-margin magmatic arc (both neutral and contractional), transform continental margin, remnant ocean, suture, and successor basin. These models are useful for understanding the following stages of development of the Cordilleran margin of central California and its environs-latest Proterozoic rifting, early Paleozoic intraplate margin, Devonian-Mississippian Antler orogeny (arc-conti nent suturing), Mississippian-Pennsylvanian intraplate margin, Pennsylvanian-Permian Ancestral Rockies orogeny (Ouachita-Marathon continental suturing), Permian-Triassic Sonoma orogeny (arc-continent suturing), Triassic-Jurassic continental-margin magmatic arc, Late Jurassic Nevadan orogeny (arc-arc suturing), latest Jurassic-Late Cretaceous continentalmargin magmatic arc, latest Cretaceous-Eocene Laramide orogeny, Oligocene ignimbrite flareup, and Miocene-Holocene triple-junction migration, transform boundary, and regional exten sion of the Great Basin. The integrated result of sequential superposition of the actualistic models produces a reasonable representation of the complexity of the study area. The discipline of applying actualistic models to the evolution of this continental margin provides new insights and forces one to consider new implications of the models. The complexity of the tectonic history of this continental margin argues against simplistic general models for the growth of continental crust.

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Section: Late Jurassic Nevadan Orogenymentioning

confidence: 91%

Phanerozoic Tectonic Evolution of Central California and Environs

Ingersoll

1997

International Geology Review

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“…The northern exposures of the imbricated BCA-Josephine Ophiolite-Rogue-Galice tectonic package represent collapse of the back-arc basin and its imbrication Tables 3 and 4. with the Chetco Arc. Harper & Wright (1985) have suggested that the Josephine Ophiolite represents oceanic crust formed in a Late Jurassic back arc where overlying flysch (Galice Formation) and volcaniclastic rocks (Rogue Formation) represent back-arc basin deposits (Riley 1987), and the Chetco Complex is the exposed roots of the arc forming the western 273 margin of the back-arc basin. Klippe of related amphibolites tectonically transported to the west in the Dothan Formationsuch as the Big Craggies, Game Lake, Red Mountain, and Gold Beach-are considered to be analogous to the BCA (Fig.…”

Section: Geologic and Tectonic Settingmentioning

confidence: 99%

The Briggs Creek Amphibolite, Klamath Mountains, Oregon: Its origin and dispersal

Coleman

Lanphere

1991

New Zealand Journal of Geology and Geophysics

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The Briggs Creek Amphibolite (BCA) in southwestern Oregon is an allochthonous slice of metamorphosed oceanic crust emplaced during the Nevadan orogenic event. Even though the evidence is not clear, the authors prefer to have the protolith for the BCA formed in a back-arc basin contemporaneously as part of the Josephine Ophiolite during late Callovian to early Oxfordian. Although major rearrangement of some of the chemical elements took place during metamorphism, it is possible, by use of major and rare earth elements, to suggest that the BCA formed in an oceanic spreading centre rather than an island arc setting. Metamorphic mineral assemblages and composition of the hornblendes indicate that metamorphism attained amphibolite facies grade.Widespread occurrence of allochthonous blocks of BCA in Western Oregon indicate that its dispersion following metamorphism can be related to the accretionary history of the continental margin. Westward thrusting of these blocks of BCA over the Chetco Arc during the Nevadan orogenic event provided blocks that slid into the outboard active Early Cretaceous trench. These blocks were then incorporated into the downgoing subduction complex and overprinted by high P/T metamorphic assemblages. Tectonic blocks within the Early Cretaceous Otter Point trench melange (Franciscan Complex equivalent) contain amphibolites correlated with the BCA and overprinted by high P/T mineral assemblages.

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“…It represents a complete ophiolite sequence overlain by silicic metasediments, the Galice Formation (Harper, 1984). The ophiolite has been dated at 157 ± 2 Ma and 164 ± 1 Ma (Saleeby et al, 1982;Wright and Wyld, 1986), and likely formed in a back-arc basin (e.g., Harper, 1980;Harper and Wright, 1984). The Josephine ophiolite and overlying Galice Formation were thrust eastward beneath the Klamath Mountains during the Nevadan orogeny, approximately 10 my after ophiolite formation.…”

Section: Geological Setting and Samplesmentioning

confidence: 99%

Serpentinite with and without brucite: A reaction pathway analysis of a natural serpentinite in the Josephine ophiolite, California

Sonzogni

Treiman

Schwenzer

2017

Journal of Mineralogical and Petrological Sciences

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A partially serpentinized peridotite from the Josephine ophiolite has been studied in detail in order to characterize the chemical processes of its serpentinization. The original rock was harzburgite, and its olivine and orthopyroxene are partially replaced by veins and patches of lizardite serpentine and magnetite; brucite and talc are completely absent from the serpentinite, regardless of whether the precursor mineral was olivine or pyroxene. Petrographic and mineral-chemical data suggest at least two phases of serpentinization. Incipient serpentinization produced lizardite and magnetite veinlets, from preferential dissolution of orthopyroxene, and/or infiltration of a silica-rich fluid. No talc or brucite was produced, which suggests this serpentinization happened in a chemically open system. Later serpentinization was from a fluid closer to Fe-Mg-Si chemical equilibrium with the harzburgite, which should in theory favor formation of a brucite-bearing serpentinite. Brucite is absent from late serpentine veins, but they have some porosity which could represent former brucite that was dissolved out or was reacted out after serpentinization. Isocon modeling suggests that Si, Fe, and K were added during serpentinization and that Ca was lost; i.e., the serpentinization was not isochemical (except for H 2 O). Results of petrographic observations, thermodynamic modeling, and mass balance calculations were used to constrain the reactions for global serpentinization of the studied sample. These reactions indicate that water with a concentration of H 2 up to two times that of deep sea vent fluids may have been produced during the serpentinization of the Josephine peridotite, which could then have been a potential host for significant biomass.

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Middle to Late Jurassic tectonic evolution of the Klamath Mountains, California‐Oregon

Cited by 135 publications

References 26 publications

Phanerozoic Tectonic Evolution of Central California and Environs

Phanerozoic Tectonic Evolution of Central California and Environs

The Briggs Creek Amphibolite, Klamath Mountains, Oregon: Its origin and dispersal

Serpentinite with and without brucite: A reaction pathway analysis of a natural serpentinite in the Josephine ophiolite, California

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