Skip to Main Content
Skip Nav Destination
GEOREF RECORD

High-resolution temporal and stratigraphic record of Siletzia's accretion and triple junction migration from nonmarine sedimentary basins in central and western Washington

Michael P. Eddy, Samuel A. Bowring, Paul J. Umhoefer, Robert B. Miller, Noah M. McLean and Erin E. Donaghy
High-resolution temporal and stratigraphic record of Siletzia's accretion and triple junction migration from nonmarine sedimentary basins in central and western Washington
Geological Society of America Bulletin (September 2015) 128 (3-4): 425-441

Abstract

The presence of early Eocene near-trench magmatism in western Washington and southern British Columbia has led to speculation that this area experienced ridge-trench interaction during that time. However, the effects of this process as they are preserved in other parts of the geologic record are poorly known. We present high-precision U-Pb zircon geochronology from Paleogene nonmarine sedimentary and volcanic sequences in central and western Washington that preserve a record of tectonic events between ca. 60 and 45 Ma. The data reveal that the Swauk, Chuckanut, and Manastash Formations formed a nonmarine sedimentary basin along the North American margin between < or =59.9 and 51.3 Ma. This basin experienced significant disruption that culminated in basinwide deformation, uplift, and partial erosion during accretion of the Siletzia terrane between 51.3 and 49.9 Ma. Immediately following accretion, dextral strike-slip faulting began, or accelerated, on the Darrington-Devil's Mountain, Entiat, Leavenworth, Eagle Creek, and Straight Creek-Fraser fault zones between 50 and 46 Ma. During this time, the Chumstick Formation was deposited in a strike-slip basin coeval with near-trench magmatism. Faulting continued on the Entiat, Eagle Creek, and Leavenworth faults until a regional sedimentary basin was reestablished < or =45.9 Ma, and may have continued on the Straight Creek-Fraser fault until 35-30 Ma. This record of basin disruption, volcanism, and strike-slip faulting is consistent with ridge-trench interaction and supports the presence of an oceanic spreading ridge at this latitude along the North American margin during the early Eocene.


ISSN: 0016-7606
EISSN: 1943-2674
Coden: BUGMAF
Serial Title: Geological Society of America Bulletin
Serial Volume: 128
Serial Issue: 3-4
Title: High-resolution temporal and stratigraphic record of Siletzia's accretion and triple junction migration from nonmarine sedimentary basins in central and western Washington
Affiliation: Massachusetts Institute of Technology, Department of Earth, Atmospheric and Planetary Sciences, Cambridge, MA, United States
Pages: 425-441
Published: 20150928
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 112
Accession Number: 2015-104854
Categories: StratigraphyStructural geology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: GSA Data Repository item 2015323
Illustration Description: illus. incl. 2 tables, geol. sketch maps
N47°00'00" - N49°00'00", W124°00'00" - W120°00'00"
Secondary Affiliation: Northern Arizona University, USA, United StatesSan Jose State University, USA, United StatesUniversity of Kansas, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201545
Close Modal

or Create an Account

Close Modal
Close Modal