Earth Sciences Commons^™

Earthquake Petrology: Linking Fault-Related Deformation To The Earthquake Cycle, Mitchell R. Prante

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Faults have a controlling influence on a variety of geologic processes including fluid flow, the mechanical behavior of the crust, and seismicity. The geologic sciences have long recognized that faults generate earthquakes; however, few indicators of ancient earthquakes exist in fault-zones. This dissertation documents several indicators for the preservation of ancient earthquakes in fault-zones including frictional melt (pseudotachylyte), highly-polished fault slip surfaces, and hydrothermal alteration.

These deformation products result from rapid generation of frictional heat during earthquakes. This dissertation also focuses on the seismic potential of continental low-angle normal faults (LANF). We document the preservation of voluminous pseudotachylyte along a …

Geochemical, Petrologic, And Structural Characterization At Multiple Scales Of Deformation Associated With The Punchbowl Fault, Southern California, Steven E. Schulz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Three traverses across the exhumed trace of the Punchbowl fault zone in the Pelona Schist, southern California, were examined at the millimeter to kilometer scales to determine the morphology, deformation mechanisms, and geochemistry of the fault zone in schistose rocks. The Pelona Schist is predominantly a quartz-albite-muscovite-actinolite schist with associated minor metabasalts. The Punchbowl fault zone, which is exhumed 2-4 km, has 44 km of right lateral slip, and is composed of a fault core enveloped by a damaged zone.

The fault core is a region of extreme slip localization that records most fault displacement. Deformation in the fault core …

Petrology Of Passive Margin-Epeiric Sea Sediments: The Garden City Formation, North-Central Utah, Susan K. Morgan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Lower Ordovician Garden City Formation is part of the thick sequence of Lower Paleozoic limestones, dolostones, and minor siliciclastic sedimentary rocks of the western United States. The carbonate rocks were formed predominantly by shallow water deposition in tropical, passive-margin epeiric seas.

The Garden City Formation is composed of nine lithotypes which represent the various environments. The formation is a storm-influenced transgressive sequence which may be divided into innershelf shallow subtidal and outer-shelf deep subtidal environments separated by a skeletal accumulation. The skeletal accumulation, formed by storm initiation, was a submerged topographic high, below normal wave base. The inner shelf …

Petrology Of Pliocene (?) Basalts Of Curlew Valley (Box Elder Co.), Utah, Steven Brent Kerr

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Basalt outcrops in Curlew Valley consist of several flow remnants and eruptive centers situated along the valley margins. Basalt is also found in association with salic rocks that erupted in the central portion of the valley. The basalts are of probable Pliocene age and were erupted during a period of active extensional tectonics. Since their emplacement, the basalts have been extensively eroded and downfaulted. The present morphology reflects the erosional and depositional processes of prehistoric Lake Bonneville.

Twelve samples were analyzed chemically for major oxides, trace elements, and rare-earth elements. The basalts form a hypersthene normative series ranging from olivine …

Petrology Of The Middle Cambrian Langston And Ute Formations In Southeastern Idaho, Daniel T. Rogers

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Middle Cambrian Langston and Ute formations were studied in the northern portion of the Bear River Range and the south-central part of the Portneuf Range in southeastern Idaho.

The rocks of the Langston and Ute formations were divided into 17 different rock types. The 17 rock types were formed within four recognizable lithofacies: I) Shoal - or Coastal-Peritidal Carbonate Complex; 2) Agitated Shoal; 3) Inner Marine Shelf; and 4) Outer Marine Shelf. Clastic sediments belonging to the Spence Shale Member of the Langston Formation (outer marine shelf) were deposited over the carbonate complex. A transgressive sequence marks the base …

Petrology Of The Late Proterozoic(?) - Early Cambrian Arumbera Sandstone And The Late Proterozoic Quandong Conglomerate, East-Central Amadeus Basin, Central Australia, Johnnie O. Phillips

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Throughout the James Ranges and Gardiner Range the Arumbera Sandstone forms prominent strike ridges with distinctive dark reddish slopes and pale red to orange-white cliffs. Because of their lithologic and stratigraphic similarities, the names Eninta and ''Quandong" for these units should be suppressed in favor of the name of Arumbera Sandstone, which has precedence. The stratigraphic and lithologic differences observed between the Quandong Conglomerate in the type locality and the Arumbera Sandstone in the study area suggest that these units are not equivalent. Similarites with the Areyonga Formation suggest the Quandong Conglomerate could be part of the Areyonga Formation.

Lithofacies …

Petrology Of The Late Proterozoic(?)-Early Cambrian Arumbera Sandstone, Western Macdonnell Ranges, North-Central Amadeus Basin, Central Australia, Lonn P. Hamp

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Arumbera Sandstone consists of mappable informal units which are repeated in a vertical, cyclic succession. Sandstones of fluvial origin form resistant strike ridges separated by strike valleys, which consist of recessive sandstones and mudrocks of marine origin.

Lithofacies 1a, 2b, and 3a are probably of marine origin in intertidal environments. Trace fossil assemblages in lithofacies 3a suggest Skolithos and Cruziana inchnofacies were present. Lithofacies 1e, 2a, 2c, 3b, and 4a are probably of fluvial origin, as the result of coalescing braided stream deposits. The Arumbera Sandstone probably was deposited in a deltaic environment characterized by low wave energy, a …

Petrology And Mineralogy Of Tertiary(?) Volcanic Rocks West And Southwest Of Kelton (Box Elder Co.), Utah, R. L. Voit

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Kelton, Utah, area has numerous, isolated basaltic outcrops of probable Tertiary age mostly in the form of cuestas with steep faces displaying columnar joints. One ash-flow tuff is located in the southeastern part of the study area. Basaltic fragments in the tuff indicate that pyroclastic activity was preceded by extrusion of basalt.

Effects of Lake Bonneville on the basaltic outcrops include wave­cut terraces, scarps, and other wave-built forms in low lying areas. Massive carbonate deposits formed at levels of former shorelines of Lake Bonneville. Tertiary and Quaternary deposits cover the low- lying areas between basaltic flows, and consist of …

The Petrology And Mineralogy Of Tertiary(?) Olivine Trachyte In The Harrington Peak Quadrangle, Southeastern Idaho, Amanda Shearer-Fullerton

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Harrington Peak Quadrangle is located within the Caribou National Forest of southeast Idaho. Within this quadrangle are outcrops of olivine trachyte of Pliocene(?) age overlying sedimentary rocks of Mississippian to Tertiary age. The region contains thrust faults and later normal faults (generally trending north-south} formed during Basin and Range extension.

The Largest outcrop of olivine trachyte (approximately1 1/2 X 3 km) probably formed as the result of a fissure eruption. Two other outcrop areas show evidence of being sites of local extrusion.

Whole-rock chemical analyses revealed the olivine trachyte to have moderate amounts of SiO₂ and Al_{2O …}

Petrology And Mineralogy Of Tertiary(?) Volcanic Rocks Of Snowville Area, Utah, And Tertiary-Quaternary(?) Volcanic Rocks Of Table Mountain And Holbrook Areas, Idaho, Yunshuen Wang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Basalt flows occur in the Snowville area of north-central Utah and the Table Mountain and Holbrook areas of south-central Idaho. All basalt flows are aphanitic in groundmass, and contain olivine, plagioclase, augite, and opaque oxides. They can be distinguished by texture. Snowville basalt has predominantly subophitic to intergranular textures. Table Mountain basalt is fine grained, with stumpy groundmass plagioclase and equant ilmenite crystals. Holbrook basalt has pilotaxitic to intergranular textures, with the presence of plagioclase phenocrysts and characteristic exsolution lamellae in Fe-Ti oxides. The olivine grains in Holbrook area are intensely oxidized to Fe-Ti oxides.

Snowville basalt contains olivine phenocrysts …

Structure And Petrology Of Tertiary Volcanic Rocks In Parts Of Toms Cabin Spring And Lucin Nw Quadrangles (Box Elder Co.), Utah, Bruce Edward Scarbrough

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A series of late Tertiary rhyolitic and dacitic flows, domes, and minor pyroclastic rocks form an elongate volanic mass along the northwestern Utah-northeastern Nevada border. The structure of the flow banding and the linear arrangement of vents indicate that the mass represents a multi-sourced extrusive complex which erupted through many fissure-type conduits. A 39 km² area at the southern end of the mass was studied in detail in order to gain a better understanding of the eruptive nature and history of these Tertiary volcanic rocks. Age dating reveals that volcanism in the study area was episodic, and covered a …

Petrology Of The Middle Jurassic Twin Creek Limestone, Lincoln And Sublette Counties, Southwestern Wyoming, David R. Raubvogel

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Twin Creek Limestone of Middle Jurassic age was studied in the Tunp, Salt River, and Wyoming Ranges in southwestern Wyoming. Modern carbonate environments and their ancient analogs were compared with information obtained from field study and petrographic analysis of samples of the Twin Creek Limestone in order to delineate environments of deposition, paleogeography, and diagenetic history.

Six major lithofacies were recognized: (1) carbonate mudstone; (2) carbonate mudstone breccia; (3) fossiliferous wackestone; (4) packstone-grainstone; (5) terrigenous mudstone; and (6) sandstone. These lithofacies were deposited in a variety of environments, including outer shelf platforms (carbonate mudstone and fossiliferous wackestone), oolitic sand …

Petrology Of The Middle Cambrian Ute Formation, North-Central Utah And Southeastern Idaho, Edward James Deputy

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Middle Cambrian Ute Formation was studied in the Bear River Range and the Wellsville Mountains of north-central Utah and southeastern Idaho. The depositional textures and sedimentary structures found within the rocks were compared with similar modern sediments and ancient rocks to determine depositional environments, paleogeography, and diagenetic alterations.

The rocks of the Ute Formation were divided into five basic types. These five rock types were formed within four identifiable lithofacies: 1) elastic marine shelf; 2) carbonate marine shelf; 3) agitated shoal; and 4) quiet-water shoal.

The sequence of elastic and carbonate sediments is believed to have been deposited in …

Petrology And Mineralogy Of Tertiary Volcanic Rocks In The Vicinity Of The Rozel Hills And Black Mountain, Box Elder County, Utah, Elizabeth R. Greenman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Two basalt flows and an andesite fissure eruption occur in the Rozel Hills - Black Mountain area in Box Elder County, Utah. Both basalt flows are aphanitic, and contain olivine, plagioclase, augite, and opaque oxides. They may be distinguished both chemically and on the basis of their textures. Unit 2 basalt is finer grained, and appears to be associated with a fault in the Black Mountain area. Chemically, it is similar to high-iron lavas in the Craters of the Moon, Idaho area. It has higher alkali, total iron, and titanium contents that Unit 1 basalt. Unit 1 basalt is similar …

Petrology Of The Lower Middle Cambrian Langston Formation, North-Central Utah And Southeastern Idaho, Gary Jay Butterbaugh

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Lower Middle Cambrian Langston Formation was studied in the Bear River Range of north-central Utah and southeasternmost Idaho and the Wellsville Mountains of north-central Utah. The depositional textures and sedimentary structures preserved within the rocks were compared with characteristics of similar modern sediments and ancient rock to determine environments of deposition, paleogeography, diagenetic alteration and pattern of dolomitization.

The rocks of the Langston Formation were divided into eleven different rock types. These eleven rock types were formed within four recognizable lithofacies: 1) upper peritidal; 2) inner carbonate shelf; 3) inner clastic shelf; and 4) outer clastic shelf.

The general …

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 …

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

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. …

Structure And Petrology Of Tertiary Volcanic Rocks Near Etna, Utah, Kent W. Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Three volcanic domes and related volcanic rocks of Tertiary age are located near Etna, Utah, in Box Elder County. The domes follow a north-south trend and are fault controlled. Flow structure indicates a change from a less viscous, flow-forming lava which produced an exogenous dome to a more viscous lava which formed endogenous domes. Associated pyroclastic deposits are negligible. The volcanic rocks are composed of porphyritic rhyolite and rhyolitic vitrophyre having phenocrysts of quartz, sanidine, plagioclase and biotite with minor amounts of Fe-Ti oxides, hypersthene, allanite and calcic amphibole. Quartz and sanidine phenocrysts are generally embayed whereas plagioclase phenocrysts are …

Petrology And Mineralogy Of Quaternary Basalts, Gem Valley And Adjacent Bear River Range, Southeastern Idaho, William D. Perkins

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Quaternary basalts of Gem Valley, Idaho, are present as valley fill (Group 1) and as well defined flows in the Bear River Range (Group 2) east of Gem Valley. Minerals present in both groups of basalts include olivine (Fo₇₃ -Fo₃₉), augite (Wo₄₁ En₃₉ Fs₂₀), plagioclase (An₇₅ -An₄₀), and Fe-Ti oxides. Coexisting pairs of magnetite and ilmenite, and olivine and clinopyroxene in several samples indicate temperatures of crystallization from 958°c to 1167°c. The Group 2 basalts exhibit a cumulate texture with abundant large (2 cm) phenocrysts of plagioclase.

Chemically, the Gem …

Petrology And Geochemistry Of The Morrison Formation, Dinosaur Quarry Quadrangle, Utah, Sue Ann Bilbey

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Mineralogical and petrographic analyses of the upper Jurassic - lower Cretaceous units in the vicinity of the Dinosaur National Monument quarry near Jensen, Utah, have elucidated their characteristics and the locations of formational boundaries. The lower part of the Morrison Formation is distinguished by a decreased amount of illite and an increased amount of kaolinite. In contrast, the underlying Curtis Formation contains an approximately equal mixture of illite and kaolinite. The lower Salt Wash Member and the upper Brushy Basin Member of the Morrison are both lithologically and mineralogically identifiable in this area. Above the boundary between the two, kaolinite …

Petrology And Regional Relationships Of The Ordovician Kinnikinic Formation And Equivalents, Central And Southern Idaho, William Calvin James

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Kinnikinic Formation of central Idaho is a sedimentary unit consisting principally of orthoquartzite. From its maximum measured thickness of 2285 feet in the central Lemhi Range near Gilmore, Idaho, it thins westward to 376 feet at the type section and southward to 326 feet near Arco, Idaho. Northeast of the Lemhi Range it occurs only as erosional remnants, due to pre-Devonian erosion. Both the lower and upper contacts of the Kinnikinic Formation are disconformable.

The Kinnikinic Formation is light colored, predominately fine to medium grained, thin to medium bedded, and largely cemented by silica overgrowths. Some metamorphic recrystallization has …

Petrology Of The Ordovician Swan Peak Formation, Southeastern Idaho And North-Central Utah, Warren J. Schulingkamp Ii

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Swan Peak Formation in southeastern Idaho and north-central Utah is a sedimentary unit consisting of orthoquartzite, sandstone, siltite, shale, and limestone. The formation is divisible into three members, and the lower two members each are divisible into two informal lithologic subunits.

The lower member consists of a lower subunit of gray, calcareous sandy siltite composed of subangular to subrounded quartz grains cemented by quartz overgrowths, calcite, or iron oxide, and an upper subunit of black shale with minor interbedded silty quartzose sandstone and biomicrite (limestone).

The middle member consists of a lower subunit of interbedded pale green shale and …