Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 5 of 5
Full-Text Articles in Earth Sciences
Petrology Of The Arumbera Sandstone, Late Proterozoic(?) - Early Cambrian, Northeastern Amadeus Basin, Central Australia, Keith T. Conrad
Petrology Of The Arumbera Sandstone, Late Proterozoic(?) - Early Cambrian, Northeastern Amadeus Basin, Central Australia, Keith T. Conrad
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The Arumbera Sandstone forms distinctive strike ridges with dark reddish slopes and orange-white cliffs throughout most of the northeastern Amadeus Basin. It is divisible into four readily mappable informal units. The ridge-forming units, 2 and 4, are divided into three and two subunits, respectively.
Unit 1, Subunit 2b, Unit 3 and Subunit 4b are generally comprised of recessive, pale-red to grayish-red, medium- to thin-bedded, fineto medium-grained arkose with major proportions of siltstone and mudshale. These sedimentary bodies are interpreted as a complex system of coastal to nearshore-marine environments including tidal flats, tidal channels, estuaries and beaches. Evidence includes: (1) predominance …
Faunal Succession And Depositional Environments Within The Lodgepole Limestone (Early Mississippian) Of Samaria Mountain, Idaho, Gary Keith Hines
Faunal Succession And Depositional Environments Within The Lodgepole Limestone (Early Mississippian) Of Samaria Mountain, Idaho, Gary Keith Hines
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Community succession, the orderly changes a community experiences with time, is considered to be the result of either autogenic or allogenic factors working singularly or in combination. It has been further suggested that, as communities undergo succession, certain biological parameters change in a predictable manner. Examination of members 2 through 4 of the Mississippian (Kinderhook-Osage) Lodgepole Formation of Samaria Mountain, Idaho provides a means to evaluate these concepts.
Within the study section comprised of 125 beds (61.5 m thick), four rock types are recognized. These include: (1) fossiliferous wackestone (78% of beds), which ranges in color from dark-gray (N3) to …
Mineralogy And Petrology Of Lava Flows (Tertiary-Quaternary) In Southeastern Idaho And At Black Mountain, Rich County, Utah, Barbara J. Puchy
Mineralogy And Petrology Of Lava Flows (Tertiary-Quaternary) In Southeastern Idaho And At Black Mountain, Rich County, Utah, Barbara J. Puchy
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Lava flows of Tertiary-Quaternary age occur in Enoch Valley, Upper Valley, and Slug Valley in southeastern Idaho. The basalts in Upper Valley and Enoch Valley contain olivine (Fo69 to Fo37), plagioclase (An62 to An39), augite and Fe-Ti oxides. The lava in Slug Valley lacks plagioclase, but contains sanidine (Or70 to Or56) with a trace of biotite and amphibole, and thus, has been termed alkali trachyte.
Black Mountain, on the eastern side of Bear Lake, northeastern Utah, is capped by basalt. Minerals present include olivine (Fo83 to Fo72), plagioclase …
Petrology Of The Middle Cambrian Blacksmith Formation, Southeastern Idaho And Northernmost Utah, David Paul Zelazek
Petrology Of The Middle Cambrian Blacksmith Formation, Southeastern Idaho And Northernmost Utah, David Paul Zelazek
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The Blacksmith Formation of Middle Cambrian (Albertan) age was studied in southeastern Idaho and northernmost Utah. Lithology and sedimentary structures were compared with modern environments and ancient rocks to determine environments of deposition, paleo-geography, diagenetic alterations and patterns of dolomitization.
The Blacksmith Formation can be divided into five basic rock types. Rock type A has cryptalgalaminae, mudcracks, and lacks bioturbation. Rock type A is inferred to have been deposited in the upper intertidal to supratidal environment. Rock type B is extremely dolomitized and brecciated. It is inferred that rock type B was deposited in the upper intertidal to supratidal environment. …
Growth-Form Analysis And Paleoecology Of The Corals Of The Late Ordovician Through Mid-Silurian Fish Haven And Laketown Formations, Bear River Range, North-Central Utah, Thomas B. Rich
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Morphology of corals of the Late Ordovician through mid-Silurian Fish Haven and Laketown Formations were analyzed to document adaptations to inferred enviromental conditions, i.e., (bathymetry, illumination, sedimentation, currents, and energy), under which their enclosing sediment was deposited. Specimens and data were collected from six sites. Insoluble-residue tests were performed on the corals' matrices.
Individual corallites of radial-lensoidal corals radiate in all directions. Vertical growth, however, was restricted in turbulent conditions. Umbrellic, radial-lensoidal corals feature downward facing corallites, considered to be an adaptation to a well illuminated environment.
On tabular lensoidal corals, constituent corallites faces exclusively upward, an orientation needed under …