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  • 1
    Keywords: Konferenzschrift ; Tektonik ; Sedimentation
    Type of Medium: Book
    Pages: V, 204 S. , Ill., graph. Darst., Kt.
    Series Statement: Special publication / Society of Economic Paleontologists and Mineralogists 22
    DDC: 551.8
    Language: English
    Note: Literaturangaben
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  • 2
    Publication Date: 2011-07-01
    Description: The McCoy Mountains Formation consists of Upper Jurassic to Upper Cretaceous siltstone, sandstone, and conglomerate exposed in an east-west-trending belt in southwestern Arizona and southeastern California. At least three different tectonic settings have been proposed for McCoy deposition, and multiple tectonic settings are likely over the [~]80 m.y. age range of deposition. U-Pb isotopic analysis of 396 zircon sand grains from at or near the top of McCoy sections in the southern Little Harquahala, Granite Wash, New Water, and southern Plomosa Mountains, all in western Arizona, identified only Jurassic or older zircons. A basaltic lava flow near the top of the section in the New Water Mountains yielded a U-Pb zircon date of 154.4 {+/-} 2.1 Ma. Geochemically similar lava flows and sills in the Granite Wash and southern Plomosa Mountains are inferred to be approximately the same age. We interpret these new analyses to indicate that Mesozoic clastic strata in these areas are Upper Jurassic and are broadly correlative with the lowermost McCoy Mountains Formation in the Dome Rock, McCoy, and Palen Mountains farther west. Six samples of numerous Upper Jurassic basaltic sills and lava flows in the McCoy Mountains Formation in the Granite Wash, New Water, and southern Plomosa Mountains yielded initial {varepsilon}Nd values (at t = 150 Ma) of between +4 and +6. The geochemistry and geochronology of this igneous suite, and detrital-zircon geochronology of the sandstones, support the interpretation that the lower McCoy Mountains Formation was deposited during rifting within the western extension of the Sabinas-Chihuahua-Bisbee rift belt. Abundant 190-240 Ma zircon sand grains were derived from nearby, unidentified Triassic magmatic-arc rocks in areas that were unaffected by younger Jurassic magmatism. A sandstone from the upper McCoy Mountains Formation in the Dome Rock Mountains (Arizona) yielded numerous 80-108 Ma zircon grains and almost no 190-240 Ma grains, revealing a major reorganization in sediment-dispersal pathways and/or modification of source rocks that had occurred by ca. 80 Ma.
    Print ISSN: 0016-7606
    Electronic ISSN: 1943-2674
    Topics: Geosciences
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  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 440 (2006), S. 408-408 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Sir Your Editorial “Science under attack” (Nature 439, 891; 200610.1038/439891a) and News story “US scientists fight political meddling” (Nature 439, 896–897; ...
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Earth and Planetary Sciences 32 (2004), S. 13-45 
    ISSN: 0084-6597
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Geosciences , Physics
    Notes: The Cordilleran orogen of western North America is a segment of the Circum-Pacific orogenic belt where subduction of oceanic lithosphere has been underway along a great circle of the globe since breakup of the supercontinent Pangea began in Triassic time. Early stages of Cordilleran evolution involved Neoproterozoic rifting of the supercontinent Rodinia to trigger miogeoclinal sedimentation along a passive continental margin until Late Devonian time, and overthrusting of oceanic allochthons across the miogeoclinal belt from Late Devonian to Early Triassic time. Subsequent evolution of the Cordilleran arc-trench system was punctuated by tectonic accretion of intraoceanic island arcs that further expanded the Cordilleran continental margin during mid-Mesozoic time, and later produced a Cretaceous batholith belt along the Cordilleran trend. Cenozoic interaction with intra-Pacific seafloor spreading systems fostered transform faulting along the Cordilleran continental margin and promoted incipient rupture of continental crust within the adjacent continental block.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 364 (1993), S. 284-285 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] EURASIA is the largest modern continent, and its immense size reflects its composite character. Over the past half-billion years, about a dozen individual continental blocks have been welded together along the sinuous lines of modern and ancient mountain belts that now interlace the ...
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 232 (1971), S. 41-42 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] There are two principal alternatives. On the one hand, the inactive continental margin on which the miogeoclinal assemblage accumulates may be activated as the consuming or overriding plate margin of a newly initiated arc-trench system. This alternative, which I shall call the activation model, ...
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 343 (1990), S. 320-320 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] sirá€"The optical illusion (Nature 341, 492; 1989) during pyrotechnic displays by which all exploding fragments appear erroneously to move toward the observer has a close parallel in the apparent motion of rotating searchlight beams. In some cities, such as ours, powerful ...
    Type of Medium: Electronic Resource
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