Journal: Geological Society of America Abstracts with Programs

Abbreviation

Abstr. program - Geol. Soc. Am.

Publisher

Geological Society of America

Journal Volumes

ISSN

0016-7592

Description

Filters

Reset filters

Search Results

Publications 1 - 7 of 7
  • Multiple cosmogenic nuclides and landscape evolution in the Atacama desert, northern Chile
    Item type: Other Conference Item
    Kober Florian; Ivy-Ochs, Susan; Schlunegger, Fritz; et al. (2006)
    Geological Society of America Abstracts with Programs
  • A tale of Two Mechanisms: New U-Pb Ages, Zircon HF Isotopic Compositions, and Spatiotemporal Context of the Coast Range Volcanics, California
    Item type: Other Conference Item
    Anttila, Eliel S.C. (2024)
    Geological Society of America Abstracts with Programs
    Volcanism in the Coast Ranges of California, spanning the latest Paleogene and the entirety of the Neogene, has been associated with mechanisms affiliated with the incipience and evolution of the transform margin between the North American and Pacific plates. These proposed mechanisms include the development of a northward-transient slab window, extensional magmatism associated with the development of the Basin and Range province, and/or the rotation of the Transverse Ranges. Here, we present a compilation of LA-ICP-MS U-Pb ages and eHf compositions of zircon from 35 Coast Range volcanic localities. Pairing of these datasets with a Paleogene-Neogene paleogeographic reconstruction of California reveals two distinct regimes of volcanism in the Californian Coast Ranges. The first regime encompasses a suite of localities, spanning ca. 3-28 Ma with a gap between ca. 12-22 Ma, that become both progressively younger and increasingly eHf-positive along a northward trajectory. The paleogeographically-reconstructed localities of eruptive centers within this regime reflect a northward migration, including across the ca. 12-22 Ma gap, that is broadly consistent with modern relative plate velocities across the Pacific-North American transform boundary. This trend likely reflects the northward migration of a slab window source. Spatially, the paleogeographically-reconstructed gap in volcanism along this northward track is broadly coincident with the present-day extent of high-velocity seismic zones around 70km deep (the Isabella Anomaly and Transverse Range Anomaly) that have been suggested to represent foundered slabs. We posit that these structures may have occluded mantle heat flux through the transient slab window, resulting in the temporary cessation of slab-window volcanism. The second regime comprises a cluster (in paleogeographically-reconstructed coordinates) of ca. 16-18 Ma eruptive centers all with similarly-positive (8-10) eHf values that do not conform to the aforementioned northward-younging trend. This second regime of Californian Coast Range volcanism is putatively associated with the incipience of extension and rotation of the Transverse Ranges.
  • Detrital (U-Th)/He thermochronometric evaluation of the Paros supradetachment basin, central Cyclades, Greece
    Item type: Other Conference Item
    Bargnesi, Evan A.; Stockli, Daniel F.; Mancktelow, Neil; et al. (2010)
    Geological Society of America Abstracts with Programs
  • Evolution and ecology of coccolithophores
    Item type: Conference Paper
    Thierstein, Hans R.; Bollmann, Jörg (2004)
    Geological Society of America Abstracts with Programs
  • Evidence for a Single Cryogenian Rift-Drift Transition from the Trout Creek Sequence and MCCOY Creek Group of Nevada and UTHA
    Item type: Other Conference Item
    Anttila, Eliel S.C. (2024)
    Geological Society of America Abstracts with Programs
    Reported stratigraphic thicknesses from the Neoproterozoic Trout Creek Sequence and McCoy Creek Group of Nevada and Utah have been incorporated into tectonic subsidence models that have been interpreted to depict a failed Cryogenian rift on the western Laurentian margin, followed by a second rift-drift transition in the Ediacaran-Cambrian transition in order to accommodate thick Cambrian successions associated with the Sauk transgressive sequence. Here, we present a new stratigraphic framework, depositional model, and age model for the Trout Creek Sequence and McCoy Creek Group of northeast Nevada and western Utah, and demonstrate that previous workers dramatically underestimated the thickness of the Ediacaran McCoy Creek Group. We combine geological mapping, stratigraphy, geochemistry, and U-Pb zircon geochronology to illustrate that these strata represent some of the most distal Neoproterozoic marine deposits preserved on the western margin of Laurentia. A tectonic subsidence model, utilizing our updated stratigraphic framework and new age model, supports a single ca. 656 Ma Cryogenian rift-drift transition, without requiring an Ediacaran-Cambrian reactivation to accommodate the Sauk transgressive sequence on the western Laurentian margin. Detrital zircon age spectra through the early Ediacaran McCoy Creek Group display limited up-section variability, consistent with the development and long-term stability of an Ediacaran western Laurentian passive margin and the progressive erosion and redeposition of the Proterozoic sedimentary cover of North America. The dearth of Grenville-age zircon in the uppermost McCoy Creek Group and appearance of jasper clasts derived from Proterozoic units in the Midcontinent, along with detrital mica and carbonate that are the products of first-generation weathering of crystalline basement, are interpreted to be associated with the ca. 570 Ma emergence of the Transcontinental Arch.
  • High-pressure infrared and X-ray powder studies of hydrogarnet and topaz-OH
    Item type: Other Conference Item
    Lager, George; Chen, Jianrong; Liu, Zhenxian; et al. (2005)
    Geological Society of America Abstracts with Programs
  • The Magnesium Isotope Budget of the Modern Oceans
    Item type: Other Conference Item
    Tipper, Edward T.; Galy, Albert; Gaillardet, Jérome; et al. (2008)
    Geological Society of America Abstracts with Programs ~ Celebrating the International Year of Planet Earth. 2008 joint annual meeting [of the] Geological Society of America
Publications 1 - 7 of 7