Provenance and Petrofacies, Upper Devonian Sandstones, Philip Smith Mountains and Arctic Quadrangles Brooks Range, Alaska
AuthorAnderson, Arlene Verona
KeywordsGeology -- Alaska -- Brooks Range
Geology, Stratigraphic -- Devonian
Sandstone -- Alaska -- Brooks Range
Facies (Geology) -- Alaska -- Brooks Range
Brooks Range (Alaska)
AdvisorConey, Peter J.
Committee ChairConey, Peter J.
MetadataShow full item record
PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the Antevs Library, Department of Geosciences, and the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author or the department.
Collection InformationThis item is part of the Geosciences Theses collection. It was digitized from a physical copy provided by the Antevs Library, Department of Geosciences, University of Arizona. For more information about items in this collection, please email the Antevs Library, firstname.lastname@example.org.
AbstractA petrographic study of upper Devonian sandstones (Endicott and Hammond Terranes), Philip Smith Mountains and Arctic quadrangles, Brooks Range, Alaska, shows that the sand-sized detritus was derived from two petrographic provenances. Detrital modes, calculated from point counts of thin sections, show that the provenance for the Devonian clastic wedge (Endicott Terrane) was a recycled orogenic belt with major components of quartz, chert, and lithic fragments. Three petrofacies are distinguished. Their distribution indicates compositional changes vertically and laterally which reflect changing compositions in the source area. A petrographically different provenance supplied the sandstones that overlie the Skajit Limestone (Hammond Terrane). Characterized by high feldspar and abundant volcanic rock fragments, this petrofacies indicates first-cycle deposition close to the source area. A magmatica arc provenance is suggested.
Degree ProgramGraduate College
Degree GrantorUniversity of Arizona
Showing items related by title, author, creator and subject.
Experiments based on blue intensity for reconstructing North Pacific temperatures along the Gulf of AlaskaWilson, Rob; D'Arrigo, Rosanne; Andreu-Hayles, Laia; Oelkers, Rose; Wiles, Greg; Anchukaitis, Kevin; Davi, Nicole; Univ Arizona, Sch Geog & Dev; Univ Arizona, Tree Ring Res Lab (COPERNICUS GESELLSCHAFT MBH, 2017-08-16)Ring-width (RW) records from the Gulf of Alaska (GOA) have yielded a valuable long-term perspective for North Pacific changes on decadal to longer timescales in prior studies but contain a broad winter to late summer seasonal climate response. Similar to the highly climate-sensitive maximum latewood density (MXD) proxy, the blue intensity (BI) parameter has recently been shown to correlate well with year-to-year warm-season temperatures for a number of sites at northern latitudes. Since BI records are much less labour intensive and expensive to generate than MXD, such data hold great potential value for future tree-ring studies in the GOA and other regions in mid- to high latitudes. Here we explore the potential for improving tree-ring-based reconstructions using combinations of RW- and BI-related parameters (latewood BI and delta BI) from an experimental subset of samples at eight mountain hemlock (Tsuga mertensiana) sites along the GOA. This is the first study for the hemlock genus using BI data. We find that using either inverted latewood BI (LWBinv) or delta BI (DB) can improve the amount of explained temperature variance by > 10 % compared to RW alone, although the optimal target season shrinks to June–September, which may have implications for studying ocean–atmosphere variability in the region. One challenge in building these BI records is that resin extraction did not remove colour differences between the heartwood and sapwood; thus, long term trend biases, expressed as relatively warm temperatures in the 18th century, were noted when using the LWBinv data. Using DB appeared to overcome these trend biases, resulting in a reconstruction expressing 18th–19th century temperatures ca. 0.5 °C cooler than the 20th–21st centuries. This cool period agrees well with previous dendroclimatic studies and the glacial advance record in the region. Continuing BI measurement in the GOA region must focus on sampling and measuring more trees per site (> 20) and compiling more sites to overcome site-specific factors affecting climate response and using subfossil material to extend the record. Although LWBinv captures the inter-annual climate signal more strongly than DB, DB appears to better capture long-term secular trends that agree with other proxy archives in the region. Great care is needed, however, when implementing different detrending options and more experimentation is necessary to assess the utility of DB for different conifer species around the Northern Hemisphere.
Alaska Native subsistence and sovereignty: An unfinished workMcGuire, Thomas; Wolf, Barbara F. (The University of Arizona., 2003)Alaska Native cultures are based on subsistence fishing, hunting and gathering, which also remain important sources of food supply. The 1971 Alaska Native Claims Settlement Act (ANCSA) extinguished all aboriginal rights to territory, hunting and fishing, creating Native corporations to own Native land in fee simple, instead of reservations with land in trust with the U.S. government (Indian country). ANCSA led to the Alaska National Interest Lands Conservation Act (ANILCA), which protects subsistence activities on federal land. Alaska followed ANILCA's subsistence guidelines on state land, until the preference was found unconstitutional in 1989. Subsistence and sovereignty today are linked to a network of interacting institutions such as tribal governments, Native corporations, ANCSA, ANILCA and court decisions. The thesis examines these and argues that institutional changes must occur for Alaska Natives to be sovereign and protect subsistence resources and culture. Suggestions include restoring Indian country to Alaska, resource co-management, and amending ANILCA.