Earth Sciences Commons^™

Structural And Hydrological Controls On The Development Of A River Cave In Marble (Tapagem Cave - Se Brazil), William Sallun Filho, Bruna Medeiros Cordeiro, Ivo Karmann

International Journal of Speleology

Tapagem Cave (or Devil’s Cave) is a river cave developed in the dolomite marble karst of the Serra do André Lopes (State of São Paulo, southeastern Brazil). Although this region is a plateau with significant variation in elevation and a humid subtropical climate, the cave is an anomalous feature in the André Lopes karst because there are few other caves. The marble, which is in a synclinal structure with subjacent phyllites, is a karst aquifer perched above the regional base level (Ribeira River) and has little allogenic recharge. The cave developed on a secondary anticline on the northwest flank of …

Morphological And Structural Mapping Of The Oudemans Impact Crater Layered Central Uplift, Mars, Bahareh Kasmai

Electronic Thesis and Dissertation Repository

Central uplifts in large meteorite impact craters provide valuable information about the subsurface geology of planetary bodies. Compared to impact craters on Earth, Martian central uplifts can be well exposed and can be mapped in detail by using satellite imagery. Central uplifts preserve morphological and structural features formed as result of the combination of emplacement during the impact process, post impact modification, and erosion over time. In this study, the Oudemans Crater central uplift (the largest central uplift with layers on Mars) was investigated. Oudemans (9.89 S, 268.1 E) is 124 km in diameter and is located in the Sinai …

Earthquake And Tsunami Forecasts: Relation Of Slow Slip Events To Subsequent Earthquake Rupture, Timothy H. Dixon, Yan Jiang, Rocco Malservisi, Robert Mccaffrey, Nicholas Voss, Marino Protti, Victor Gonzalez

Geology Faculty Publications and Presentations

The 5 September 2012 Mw 7.6 earthquake on the Costa Rica subduction plate boundary followed a 62-y interseismic period. High-precision GPS recorded numerous slow slip events (SSEs) in the decade leading up to the earthquake, both up-dip and down-dip of seismic rupture. Deeper SSEs were larger than shallower ones and, if characteristic of the interseismic period, release most locking down-dip of the earthquake, limiting down-dip rupture and earthquake magnitude. Shallower SSEs were smaller, accounting for some but not all interseismic locking. One SSE occurred several months before the earthquake, but changes in Mohr–Coulomb failure stress were probably too small to …

Qualitative Comparison Of Offset Surfaces Between The Central And Eastern Garlock Fault, Thomas M. Crane

Electronic Theses, Projects, and Dissertations

The Garlock Fault consists of three distinct segments, known as western, central, and eastern, together reaching approximately 260 km from the San Andreas Fault to the southern end of Death Valley. Although published slip rates are available along the western and central Garlock Fault segments, little is currently known of the Garlock Fault earthquake history or slip rate farther east. Using LiDAR and satellite imagery, the central and eastern Garlock Fault segments were analyzed for visibly offset, fault-adjacent, geomorphic surfaces that may potentially be used for estimating slip rate. Qualitative methods of assessing preserved alluvial surface maturity were adapted and …

Thermal Impacts Of Salt On Sandstones And Mudstones In The Lusitanian Basin, Portugal, Brett Perry

UNLV Theses, Dissertations, Professional Papers, and Capstones

In order to assess the impact of salt structures on paleotemperatures in adjacent sedimentary rocks, a field based study which quantified thermally driven diagenetic products as a function of distance from salt was undertaken. Several salt diapirs are now exposed at the surface of the Earth within the Lusitanian Basin and offered a unique opportunity to document paleothermal anomalies by studying thermally controlled diagenesis in adjacent, exposed Upper Jurassic rocks. Four transects were chosen within Upper Jurassic rocks that contained both sandstones and mudstones. Quartz cementation and albitization of feldspars, both of which are thermally driven processes, were quantified in …

The Timing Of Deformation In The Four Peaks Area, Central Arizona, And Relevance For The Mazatzal Orogeny, Calvin A. Mako

Masters Theses

The Mazatzal orogeny (1.66-1.60 Ga) is a key element of the tectonic evolution of the North American continent during the Proterozoic (Whitmeyer and Karlstrom, 2007). Recently, Mesoproterozoic detrital zircon grains (1.55-1.45 Ga) have been found in metasedimentary rocks that were thought to have been deformed during the Paleoproterozoic Mazatzal orogeny (Jones et al. 2011; Doe et al. 2012, 2013; Daniel et al. 2013). Some type examples Mazatzal deformation now seem to be too young to have been deformed in the accepted time of that orogeny (1.66-1.60 Ga) and may have been deformed in the younger, newly defined, Picuris orogeny. This …

From ~1.5 Ma To Today: Insights Into The Southern San Andreas Fault System From 3d Mechanical Models, Laura Fattaruso

Masters Theses

Three-dimensional mechanical simulations of the San Andreas fault (SAF) within the Coachella Valley in California produce deformation that match geologic observations and demonstrate the impact of fault geometry on uplift patterns. Most models that include the Coachella Valley segment of the SAF have assumed a vertical orientation, but recent studies suggest that this segment dips 60-70° northeast. We compare models with varied fault geometry and evaluate how well they reproduce observed uplift patterns. Our model with a dipping SAF matches geologic observations, while models containing a vertical fault do not. This suggests that the active Coachella Valley segment of the …

Mapping The Natural History Of The Panama Canal Zone, Casey Calamaio

Von Braun Symposium Student Posters

No abstract provided.

Sedimentology Of The Upper Scotland Formation (Eocene), Barbados, Krishna Mahabir, Nazrul I. Khandaker, Jay P. Persaud, Stanley Schleifer

Publications and Research

Representative samples collected from the Lower Scotland Formation (Eocene) outcropping in northeastern Barbados were investigated in conjunction with overall facies distribution and stratigraphic and sedimentological characteristics to interpret depositional environment and provenance of the fine-grained clastics. The Lower Scotland Formation is, for the most part, a fine-grained clastic-dominated sequence with occasional thin intercalations of gypsum, ironstone, and kaolinite. Distinctive deep-water-facies have been well-documented in dark gray shale units containing load cast, flutes, grooves and prods. In addition, turbiditic brown sandstone with a sharp erosive base and pelagic caps also characterize the base of the formation. Notable marine fauna observed include …

Interseismic Locking On The Hikurangi Subduction Zone: Uncertainties From Slow-Slip Events, Robert Mccaffrey

Geology Faculty Publications and Presentations

lnterseismic locking on the Hikurangi subduction zone in New Zealand is examined in light of alternative assumed locking distributions and the impact of transients (slow-slip and volcanic sources) on temporal and spatial resolution. The modern pattern of locking in the north is poorly resolved and, based on simulations of possible transient behavior, may be an ephemeral feature of the subduction cycle. While there appears to be some contemporary locking in the northern half of the Hikurangi subduction zone (HSZ), its location is model dependent, and hence, its relationship to structure, slow-slip, or any transition zone there is unclear. Simulations of …

Crustal Accretion And Mantle Geodynamics At Microplates: Constraints From Gravity Analysis And Numerical Modeling, Katherine Ames

OES Theses and Dissertations

This study investigates crustal accretion and mantle geodynamics at microplates using mantle Bouguer anomaly (MBA) gravity calculations and exploratory numerical models. The Easter and Juan Fernandez microplates are located in the eastern Pacific Ocean along the Pacific, Nazca, and Antarctic plate boundaries. Both microplates formed 3-5 Ma and they are currently rotating clockwise at 15° myr^-1 and 9° myr^-1,respectively [ e.g., Searle et al., 1993]. The study area also encompasses the Easter /Salas y Gomez mantle plume located near the Easter microplate. Both microplates show a difference in average MBA between their west and east ridges, with …

Clockwise Rotation Of The Brahmaputra Valley Relative To India: Tectonic Convergence In The Eastern Himalaya, Naga Hills, And Shillong Plateau, ‪Philippe Vernant, R. Bilham, Walter Szeliga, D. Drupka, S. Kalita, A. K. Bhattacharyya, V. K. Gaur

All Faculty Scholarship for the College of the Sciences

GPS data reveal that the Brahmaputra Valley has broken from the Indian Plate and rotates clockwise relative to India about a point a few hundred kilometers west of the Shillong Plateau. The GPS velocity vectors define two distinct blocks separated by the Kopili fault upon which 2–3 mm/yr of dextral slip is observed: the Shillong block between longitudes 89 and 93°E rotating clockwise at 1.15°/Myr and the Assam block from 93.5°E to 97°E rotating at ≈1.13°/Myr. These two blocks are more than 120 km wide in a north‐south sense, but they extend locally a similar distance beneath the Himalaya and …

Thermodynamic Model For Energy-Constrained Open-System Evolution Of Crustal Magma Bodies Undergoing Simultaneous Recharge, Assimilation And Crystallization: The Magma Chamber Simulator, Wendy A. Bohrson, Frank J. Spera, Mark S. Ghiorso, Guy Brown, Jeffrey Creamer, Aaron Mayfield

All Faculty Scholarship for the College of the Sciences

The Magma Chamber Simulator quantifies the impact of simultaneous recharge, assimilation and crystallization through mass and enthalpy balance in a multicomponent–multiphase (melt + solids ± fluid) composite system. As a rigorous thermodynamic model, the Magma Chamber Simulator computes phase equilibria and geochemical evolution self-consistently in resident magma, recharge magma and wallrock, all of which are connected by specified thermodynamic boundaries, to model an evolving open-system magma body. In a simulation, magma cools from its liquidus temperature, and crystals ± fluid are incrementally fractionated to a separate cumulate reservoir. Enthalpy from cooling, crystallization, and possible magma recharge heats wallrock from its …

New Research In Cave Ledenica In Bukovi Vrh On Velebit Mt In Croatian Dinaric Karst, Mladen Garasic

The International Workshop on Ice Caves

No abstract provided.

Characterizing The Relationship Of Part Of The Inner Piedmont And Pine Mountain Window, Georgia, From Detailed Geologic Mapping, Geochemistry, Geochronology, And Structural Analysis At The Southwestern End Of The Cat Square Terrane, Justin Randolph Rehrer

Masters Theses

Geologic investigations at the southwestern end of the Cat Square terrane (CSt) in central Georgia provided new insight into the complex tectonic history of the Pine Mountain window (PMw) and neighboring Inner Piedmont terranes. Detailed 1:24,000-scale geologic mapping of an approximately 180 km2 area near Barnesville, Georgia has provided the foundation for further geochemical, geochronologic, and structural analyses refining models for tectonic development and emplacement of the CSt and PMw.

Whole-rock geochemical analyses of several CSt amphibolites yielded data suggesting a continental back-arc setting for genesis of the Cat Square basin (CSb). Major element data confirm derivation from a basaltic …

Possible Sources For Nickel And Chromium In The Middle Part Of The Fillmore Formation In West-Central Utah, Rachel Nyznyk, Benjamin Dattilo

Benjamin F. Dattilo

Nickel and chromium are not commonly found in carbonate or mixed carbonate depositional environments. All lithologies from a 100-meter section in the middle part of the Lower Ordovician Fillmore Formation at a single locality, the “Pyramid Section”, contain anomalous levels of nickel and chromium. Preliminary data has also shown that there is significantly more nickel in the matrix of two FPCs (range of 0.22 – 0.24 ppm) from the pyramid section than found in the other lithologies at that section (0.05 – 0.10 ppm). However, at a separate locality, “Section C”, in the lower part of the Fillmore Formation neither …

Provenance, Sorting, And Secular Variation In Late Cambrian And Early Ordovician Carbonate Flat-Pebble Conglomerates In West-Central Utah, Rachel Nyznyk, Benjamin Dattilo, Kevin Evans

Benjamin F. Dattilo

Flat-pebble conglomerates (FPCs) are deposits that include tabular clasts of carbonate facies in shallow marine successions. They are common features in Cambrian and Ordovician successions and are more rarely preserved in post-Ordovician strata. Traditional interpretations suggest they are storm deposits, but more recently, they have interpreted as cycle caps and products of sea-level change. Examining FPCs in detail may further our understand of possible origins, including major Earth events such as meteorite impacts, seismic events, superstorms, slope failures, and mass wasting events. This study, which is in its initial phase, examines FPCs based on intrinsic features and seeks to document …

The Great American Carbonate Bank In The Miogeocline Of Western Central Utah: Tectonic Influences On Sedimentation., James Miller, Kevin Evans, Benjamin Dattilo

Benjamin F. Dattilo

No abstract provided.

Exhumation Of The Baranof Schist In Whale Bay Alaska Determined Through Zircon Fission Track Dating, Kate Kaminski

Honors Theses

During the Eocene in the North Pacific, the Kula, Farallon, and Pacific plates met in a trench-ridge-trench triple junction, bordered to the east by a continental margin along the edge of the North American plate. The flysch of the Chugach-Prince William terrane, a deformed accretionary complex, accreted onto this margin in the late Cretaceous to Paleocene. This terrane is framed to the north by the Border Ranges fault, a large strike-slip fault system that has accommodated northward movement of the Chugach-Prince William since the Eocene. One of the easternmost units of the Chugach-Prince William is the Baranof Schist on Baranof …

Assessing Layer Parallel Shortening In The Eastern Colorado Front Range Using Thin Section Analysis And Analog Sandbox Models, Nicole Pierson

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Layer parallel shortening (LPS) is an expression of compressive strain that occurs parallel to bedding surfaces. LPS is chiefly expressed by chemical changes to sediment volume, including stylolitization, porosity reduction and impingement of grains. This strain is typically omitted in the process of cross-section restoration due to a lack of understanding of spatial and temporal LPS accommodation. Bulk shortening calculated is considered to be a minimum shortening estimate. However, dismissing this inaccuracy due to shortening can lead to significant error in subsurface predictions and reconstructions.

To address this problem, a combination of thin section analysis and analog modeling assessed the …

Fabric And Microstructural Analysis Of The Loch Borralan Pluton, Northwest Highlands, Scotland, Justin Calhoun

Theses and Dissertations

The Loch Borralan pluton was emplaced within the Assynt Region of the Moine Thrust zone during the Scandian event (ca. 435-425 Ma) of the Caledonian Orogeny (478-425 Ma). It consists of two major magma suites, the syenitic early suite (431.1 ± 1.2 Ma), and the quartz syenitic later suite (429.2 ± 0.5 Ma). The region is characterized by a series of in-sequence thrust faults that strike NE-SW and dip approximately 20± to the SE, including (from lower to upper): the Sole Thrust, the Borralan Thrust (hypothesized, but not exposed), the Ben More Thrust, and the Moine Thrust. A series of …

Combining Quantitative Eye-Tracking And Gis Techniques With Qualitative Research Methods To Evaluate The Effectiveness Of 2d And Static, 3d Karst Visualizations: Seeing Through The Complexities Of Karst Environments, Elizabeth Katharyn Tyrie

Masters Theses & Specialist Projects

Karst environments are interconnected landscapes vulnerable to degradation. Many instances of anthropogenic karst disturbance are unintentional, and occur because of the public's lack of understanding or exposure to karst knowledge. When attempts are made to educate the general public about these landscapes, the concepts taught are often too abstract to be fully understood. Thus, karst educational pursuits must use only the most efficient and effective learning materials. A technique useful for assessing educational effectiveness of learning materials is eye-tracking, which allows scientists to quantitatively measure an individual's points of interest and eye movements when viewing a 2D or 3D visualization. …

Structural Analysis Of The Tablerock Thrust Sheet, Grandfather Mountain Window, Northwestern North Carolina: Emplacement Kinematics Of A Large Horse In A Major Thrust System, Ann Elizabeth Walker

Masters Theses

The Tablerock thrust sheet is exposed along the southwestern margin of Grandfather Mountain window in northwestern North Carolina, where it separates basement and cover rocks inside the window from basement thrust sheets of the overriding Blue Ridge-Piedmont megathrust sheet. It is a complex of footwall-derived horses of rifted-margin metasedimentary rocks, including Neoproterozoic to Early Cambrian Chilhowee Group quartzite and phyllite, and Shady Dolomite. Penetrative deformation throughout the Tablerock thrust sheet is defined by an extensively transposed foliation, and strong colinearity between well developed transport lineations and SE/NW-trending tight, isoclinal, and sheath folds. Centimeter- to meter-scale sheath folds are common throughout …

Analysis Of Quartz Grain Deformation Along The Llanganuco Canyon Of The Cordillera Blanca Fault, Peru, Tami Laurene Banks

EURēCA: Exhibition of Undergraduate Research and Creative Achievement

No abstract provided.

Shear Zone Influence On The Emplacement Of A Giant Pegmatite: The Whabouchi Lithium Pegmatite, Quebec,Canada, Laurisha Bynoe

Electronic Thesis and Dissertation Repository

The Whabouchi pegmatite is within a transpressional high-strain zone of a metamorphosed volcano-sedimentary belt. A well-developed subvertical transposition foliation and a subvertical stretching lineation are present in this zone. The main body of the Whabouchi pegmatite is parallel to the transposition foliation and branching veinlets from this body have been folded and boudinaged by shear zone deformation. Thus suggesting that the Whabouchi pegmatite intruded syn-kinematically during the deformation of the shear zone. Previously, the Whabouchi pegmatite gave a zircon age of 2577 + 14Ma. The Whabouchi pegmatite is linked geochemically and geochronologically to a large pegmatite body to the south …

Part I: Neoacadian To Alleghanian Foreland Basin Development And Provenance In The Central Appalachian Orogen, Pine Mountain Thrust Sheet Part Ii: Structural Configuration Of A Modified Mesozoic To Cenozoic Forearc Basin System, South-Central Alaska, Peter Benjamin Robertson

Open Access Theses

Foreland and forearc basins are large sediment repositories that form in response to tectonic loading and lithospheric flexure during orogenesis along convergent plate boundaries. In addition to their numerous valuable natural resources, these systems preserve important geologic information regarding the timing and intensity of deformation, uplift and erosion history, and subsidence history along collisional margins, and, in ancient systems, may provide more macroscopic information regarding climate, plate motion, and eustatic sea level fluctuations. This thesis presents two studies focused in the Paleozoic Appalachian foreland basin system along the eastern United States and in the Mesozoic to Cenozoic Matanuska forearc basin …

A Geochemical Study Of Crustal Plutonic Rocks From The Southern Mariana Trench Forearc: Relationship To Volcanic Rocks Erupted During Subduction Initiation, Julie A. Johnson

FIU Electronic Theses and Dissertations

Two suites of intermediate-felsic plutonic rocks were recovered by dredges RD63 and RD64 (R/V KK81-06-26) from the northern wall of the Mariana trench near Guam, which is located in the southern part of the Izu-Bonin-Mariana (IBM) island arc system. The locations of the dredges are significant as the area contains volcanic rocks (forearc basalts and boninites) that have been pivotal in explaining processes that occur when one lithospheric plate initially begins to subduct beneath another. The plutonic rocks have been classified based on petrologic and geochemical analyses, which provides insight to their origin and evolution in context of the surrounding …

Seismic And Geodetic Evidence For Grounding-Line Control Of Whillans Ice Stream Stick-Slip Events, Martin J. Pratt, J. Paul Winberry, Douglas A. Wiens, Sridhar Anandakrishnan, Richard B. Alley

All Faculty Scholarship for the College of the Sciences

The tidally modulated, stick‐slip events of Whillans Ice Stream in West Antarctica produce seismic energy from three locations near the grounding line. Using ice velocity records obtained by combining time series from colocated broadband seismometers and GPS receivers installed on the ice stream during the 2010–2011 and 2011–2012 austral summers, along with far‐field seismic recordings of elastic waves, we locate regions of high rupture velocity and stress drop. These regions, which are analogous to “asperities” in traditional seismic fault studies, are areas of elevated friction at the base of the ice stream. Slip events consistently initiate at one of two …

The Latte Gold Zone, Kaminak's Coffee Gold Project, Yukon, Canada: Geology, Geochemistry, And Metallogeny, Eric Buitenhuis

Electronic Thesis and Dissertation Repository

The Latte Gold Zone is hosted within complexly tectonically imbricated metamorphic rocks of the Yukon-Tanana terrane. Snowcap assemblage psammitic schist and amphibolite with exotic Slide Mountain ultramafics overthrusts unidentified arc metavolcanics which in turn overthrust the Late Permian Sulphur Creek orthogneiss. Rapid unroofing of the Dawson Range during the Mid-Cretaceous culminated in dextral movement along the Coffee Creek fault system. A set of stacked, ESE–WNW trending, steeply dipping brittle fault structures served as conduits for gold-bearing fluids. Core-logging, detailed petrography, microprobe analysis, and PIMA investigations indicate that Latte is an epizonal orogenic gold deposit. Gold is hosted within arsenian pyrite …

Tidal Pacing, Skipped Slips And The Slowdown Of Whillans Ice Stream, Antarctica, J. Paul Winberry, Sridhar Anandakrishnan, Richard B. Alley, Douglas A. Wiens, Martin J. Pratt

All Faculty Scholarship for the College of the Sciences

We summarize new observations of the deceleration and stick–slip motion of Whillans Ice Stream (WIS), Antarctica. We refine the location of the large sticky spots that resist motion between slip events, the locations of which are controlled by the patterns of subglacial water flow. Our examination of the long-term velocity time series for the ice stream reveals that the decadal-scale deceleration is not occurring at a steady rate, but varies at the sub-decadal timescale. This unsteady deceleration modulates the temporal evolution of a broad (~50 km across) surface-elevation bulge forming at the junction between the relatively narrow upstream portion of …