CaltechAUTHORS
  A Caltech Library Service

Geology of southern Prince of Wales Island, southeastern Alaska

Gehrels, George S. and Saleeby, Jason B. (1987) Geology of southern Prince of Wales Island, southeastern Alaska. Geological Society of America Bulletin, 98 (2). pp. 123-137. ISSN 0016-7606. https://resolver.caltech.edu/CaltechAUTHORS:20140825-152632623

Full text is not posted in this repository. Consult Related URLs below.

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20140825-152632623

Abstract

Geologic mapping on southern Prince of Wales Island combined with U-Pb (zircon) geochronologic, geochemical, and conodont studies yield new information about the early Paleozoic geologic framework and evolution of the southern Alexander terrane. The oldest rocks recognized consist of arc-type(?) meta-volcanic and metasedimentary rocks (Wales metamorphic suite) which were derived from late Proterozoic(?)-Cambrian protoliths. These rocks were deformed, metamorphosed, and uplifted during the Middle Cambrian-Early Ordovician Wales orogeny. Beginning soon after this orogenic event and continuing into Early Silurian time, basaltic to rhyolitic rocks and marine clastic strata (Descon Formation) were deposited, and dioritic to granitic plutons were emplaced. A variety of geochemical data suggest that these Ordovician-Early Silurian rocks formed in a volcanic-arc environment. The middle Silurian-earliest Devonian Klakas orogeny marked the end of arc-type magmatism; it is manifest on southern Prince of Wales Island by regional imbrication on southwest-vergent thrust faults, penetrative brecciation and pervasive hydrothermal alteration of pre-Devonian rocks in some areas, and at least several kilometres of structural uplift. Lower Devonian strata (Karheen Formation) record the waning stages of this event: conglomeratic redbeds low in the section were deposited in topographically rugged, subaerial to shallow-marine environments, whereas strata high in the section were deposited in more distal marine environments. Post-Devonian rocks on southern Prince of Wales Island include the Bokan Mountain Granite (Jurassic), basaltic to dacitic(?) dike swarms, and mid-Cretaceous granodiorite and diorite bodies. Prior to emplacement of the mid-Cretaceous plutons, the Devonian and older rocks were offset along several sets of strike-slip faults and then downdropped along the Keete Inlet fault.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1130/0016-7606(1987)98<123:GOSPOW>2.0.CO;2 DOIArticle
http://gsabulletin.gsapubs.org/content/98/2/123PublisherArticle
http://bulletin.geoscienceworld.org/content/98/2/123PublisherArticle
Additional Information:© 1987 Geological Society of America. Manuscript received by the Society January 21, 1986; Revised manuscript received September 25, 1986; Manuscript accepted September 29, 1986. Our field and geochronologic studies on southern Prince of Wales Island have been supported by the U.S. Geological Survey and by research grants awarded to Gehrels from the California Institute of Technology, the Geological Society of America, and Sigma Xi. Henry C. Berg (retired, U.S. Geological Survey) supervised our work and assisted in mapping part of the area. His enthusiasm and support have been invaluable. Ryan Turner also assisted in mapping part of the area during the summer of 1982. Fred Barker (U.S. Geological Survey) supervised the collection of the geochemical data reported herein and kindly allowed us to publish the data, and Norman Savage (University of Oregon) analyzed the conodonts in limestone samples collected during the study. James Chen and Leon T. Silver assisted in our geochronologic studies. We thank Bill Block (Noranda Exploration Co.) for his generosity in providing helicopter support, aerial photographs, and insights into the regional geologic framework of southern Prince of Wales Island. Doug Oliver (Houston Oil and Minerals Co.) also provided helicopter support for mapping in part of the interior of the island. Don Eberlein (retired, U.S. Geological Survey) initiated our interest in the area and shared with us the information that he gathered from the Klakas Inlet area between 1949 and 1979, and that he, Michael Churkin, Jr., and Walter Vennum collected from the Kassa-Klakas Inlets region in 1972. Earl Redman (U.S. Bureau of Mines) and Tom Bundtzen (Alaska Division of Geological and Geophysical Surveys) shared with us information about parts of the study area, as well.
Funders:
Funding AgencyGrant Number
USGSUNSPECIFIED
CaltechUNSPECIFIED
Geological Society of AmericaUNSPECIFIED
Sigma XiUNSPECIFIED
Issue or Number:2
Record Number:CaltechAUTHORS:20140825-152632623
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20140825-152632623
Official Citation:GEORGE E. GEHRELS and JASON B. SALEEBY Geology of southern Prince of Wales Island, southeastern Alaska Geological Society of America Bulletin, February, 1987, v. 98, p. 123-137, doi:10.1130/0016-7606(1987)98<123:GOSPOW>2.0.CO;2
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:48863
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:25 Aug 2014 23:21
Last Modified:03 Oct 2019 07:08

Repository Staff Only: item control page