Physical Sciences and Mathematics Commons^™

Provenance, Composition And Transport Processes Of Pleistocene-Recent Turbidite Sediments Of The Se Nazca Plate, Odp Site 1232, Kimberly D. Beck

FIU Electronic Theses and Dissertations

A 300 meter sequence of Pleistocene turbidite deposits was recovered on the Nazca Plate at the subducting edge of the Peru-Chile Trench at ODP Site 1232. Analysis of the coarsest particles in the turbidite sequences implies sediment was supplied in some proportion by terrestrial erosion and originated in the coastal, central, and Andean volcanic/magmatic belt which parallels the Southern Chilean coast, and the predominant material type is volcanic. Petrographic and geochemical analyses show that samples from 3 - 140 mbsf contain >43% fresh, angular glass. New calcareous nannofossil biostratigraphy brackets the sediment ages of the upper 288 m of cored …

Hydrologic Properties Of Mangrove And Sawgrass Peat In Shark River Slough, Everglades, Florida, Nicole Cordoba

FIU Electronic Theses and Dissertations

Peat sediments are the foundation of most wetlands, acting as a medium for water to flow through, governed by hydraulic conductivity, and as a potential source of nutrients. Shark River Slough is a known, main fresh waterway for Everglades National Park, distributing essential nutrients and freshwater into the wetland. Hydraulic conductivity was calculated through experimental (both in situ water and higher salinity water) falling head tests performed on mangrove and sawgrass peat cores. Nutrient concentrations were analyzed for the pore water released during hydrologic testing. Hydraulic conductivity values were higher in the sawgrass peat than the mangrove peat. No significant …

Comparison Of Modern And Mid-Holocene Benthic Foraminifera To Assess Recent Environmental Change In Almirante Bay, Caribbean Panama, Maria N. Gudnitz

FIU Electronic Theses and Dissertations

This study used the diversity and distribution of benthic foraminiferal assemblages of Almirante Bay, Caribbean Panama, as environmental proxies to compare modern coral, seagrass and mangrove habitats to mid-Holocene coral reef facies on the island of Isla Colón, to investigate both natural and human-influenced changes.

The modern study associated species and assemblage characteristics with environmental conditions related to degraded water quality. Assemblages were fairly similar among neighboring habitats but differed in species proportions, while several stress-tolerant taxa might indicate eutrophic conditions. Diversity appeared to be regionally controlled by freshwater input irrespective of habitat type, was generally lower near the mainland …

Hydrogeophysical Characterization And Imaging In The Mangrove Lakes Region Of Everglades National Park And Big Pine Key, Florida, Usa, Michael Eyob Kiflai

FIU Electronic Theses and Dissertations

Coastal groundwater aquifers are susceptible to saltwater intrusion from natural and anthropogenic sources. Everglades National Park (ENP) has been adversely impacted by past human activities that altered freshwater flow through the system. In Big Pine Key (BPK), the flat and low-lying topography less than 2m makes the freshwater lens vulnerable to tidal and storm surge events. This study investigated different inversion scenarios and used Electrical Resistivity Tomography (ERT) and Electromagnetic (EM) survey to characterize the spatial and temporal change of the groundwater chemistry and image the aquifers. In Big Pine Key, Hurricane Irma made landfall as a category 4 storm …

Modeling Drought, Drought Teleconnection, And Its Effect On Groundwater Level Dynamics In The Biscayne Aquifer, Anteneh Z. Abiy

FIU Electronic Theses and Dissertations

Developing a self-sufficient water supply system in Southeast Florida is one input to the success of the ongoing restoration effort in the Everglades. Maintaining a high groundwater level in the urban side of the Biscayne Aquifer (BA) is important to sustain the urban water supply. However, the long-term groundwater table condition in the Biscayne Aquifer (BA) is threatened by a combination of drought, groundwater pumping, and sea-level rise. Further, the long-term drought pattern, drought drivers, and the aquifer’s response to drought and other stress conditions are not well known. As a result, options that would help to maintain a high …

Volcanic History Of The Izu Bonin Mariana Arc Prior To The First Arc Rift From Volcaniclastic Sediments Of Dsdp Site 296 And Iodp Site 1438, Eshita Samajpati

FIU Electronic Theses and Dissertations

The Izu-Bonin Mariana (IBM) island arc in the western Pacific basin is a volcanic chain formed by subduction of the Pacific lithospheric plate beneath the Philippine Sea plate. Worldwide, subduction causes high-magnitude earthquakes and explosive volcanic activity in addition to forming the Earth’s continental crust and major ore deposits, thus its understanding is important to human concerns. In the IBM, volcanic activity spans 50 million years to the present and the arc has undergone extension and periodic rifting, preserving remnants of its early history. The Kyushu Palau ridge (KPR), an inactive Oligocene remnant of the rifted IBM system, is a …

Lithological And Geochemical Responses To Abrupt Global And Regional Paleoenvironmental Changes During The Aptian In A Hemipelagic Setting Of The Eastern Iberian Peninsula: A Multi-Proxy Approach, Jander Socorro

FIU Electronic Theses and Dissertations

Intense episodes of environmental perturbations and regionally to globally distributed, oxygen-deprived marine facies characterize the Cretaceous sedimentary record. The Organyà Basin in the Spanish Pyrenees chronicles this period in expanded stratigraphic sequences that enabled high-resolution sampling and detailed analysis of disturbances poorly recorded in more lithologically condensed sections. Here, I present an integrated multi-proxy study aimed at understanding the Basin’s response to changing paleoenvironmental conditions during the early Aptian stage of the Cretaceous.

Results from the El Pui section indicate that large-scale (> 1‰), negative carbon isotope excursions (CIEs) that show no corresponding shifts in local sources of organic matter …

Identifying The Origins Of Volcanic Ash Deposits Using Their Chemical And Physical Compositions, Emmanuel Soto

FIU Electronic Theses and Dissertations

Recent ocean sediments collected offshore Chile by Ocean Drilling Program Leg 202 contained layers of volcanic ash of unknown origin. These deposits may have originated from sources in the Southern Volcanic Zone (SVZ) within the Andean Volcanic Belt to the east, or from explosive volcanoes in the southwestern Pacific transported by westerly prevailing winds. In this study, mineral and glass textures and compositions of Leg 202 ashes were evaluated to try to determine the sources of the ash layers. Ash fragments were imaged and analyzed for major elements using an SEM with X-Ray detector and for trace elements using LA-ICPMS. …

Paleoenvironments, Origin, And Relative Maturity Of Organic Matter In Barremian-Aptian Limestones Of The Eastern Prada Quarry, Organyà Basin, Ne Spain, Jose R. Llaguno

FIU Electronic Theses and Dissertations

This study is a multi-proxy analysis of a 30-m section of a Barremian-Aptian succession of interbedded, grayish black (N2) and black (N1) limestones from a quarry of the Sierra de Prada. Index taxa include planktic foraminifera Globigerinelloides blowi and Hedbergella sigali, which combined with δ¹³C data from Cresmina and Gorgo a Cerbara sections indicate a late Barremian to early Aptian age. The rocks are organic-rich with 0.67 - 3.10 wt% total organic carbon (TOC). A marlstone interval (~1m) at 2.24 m has a low bioturbation index (1), TOC ~6.66 wt%, framboidal pyrite, and enrichment spikes of major, …

Investigating The Effects Of Land-Cover Change On The Hydrologic Conditions Of A Restored Agricultural Area In Everglades National Park, Dillon Reio

FIU Electronic Theses and Dissertations

In the Florida Everglades, remodeling of natural wetlands to promote agriculture and human settlement, have profoundly altered its hydrologic regime. As a result of anthropogenic changes, many restoration programs have been initiated to restore hydrologically controlled wetland ecosystems. One such restoration project that has been ongoing for the past 27 years is the Hole-in-the-Donut restoration program in Everglades National Park. The restoration program is unique in that it utilized an unorthodox technique to restore the landscape. The viability of the restoration technique was assessed by coupling long-term hydrologic and evapotranspiration data with water chemistry analyses. Key results indicated that the …

Water-Rock Interactions And Seasonal Hydrologic Processes In Constructed Everglades Tree Islands, Andres E. Prieto Estrada

FIU Electronic Theses and Dissertations

The decline of tree islands in the freshwater-Everglades wetland because of hydrologic manipulation, has compromised valuable ecosystem services. Although the role of tree islands in maintaining freshwater quality stems largely from evapotranspiration processes, fundamental questions remain about the effects of different geologic materials on their hydrogeochemical functioning. To reduce this uncertainty, the lithological composition of a set of man-made tree islands was investigated coupled with long-term hydrologic and hydrochemical data. Key results indicate that limestone substrates and peat substrates with elevated proportions of sand, facilitated surface water-groundwater interactions and mineral dissolution. However, limestone-based islands were more effective in lowering the …

Simple Models For Underdamped Slug Tests In High Permeability Aquifers, Maria E. Marquez

FIU Electronic Theses and Dissertations

Accurate hydraulic conductivity values are necessary for understanding groundwater flow. Methods for estimating hydraulic conductivity show limitations because measured values vary several orders of magnitude in high permeability aquifers. Slug tests, while cost and time efficient, result in values lower than expected. It is proposed that underdamped behavior of water in a well is similar to mass on a damped spring; hence, models constructed to simulate behavior independent of aquifer effects might replicate some tests. The Poiseuille and Darcy-Weisbach models, and extensions of these models considering entry/exit effects, are applied to an aquifer-free laboratory test, and real wells. Aquifer-free laboratory …

Neogene Changes In Caribbean Paleoproductivity And The Diversity And Paleobiogeography Of Deep-Sea Benthic Foraminifera, Crystal Pletka

FIU Electronic Theses and Dissertations

The Neogene history of Caribbean deep-sea benthic foraminifera was investigated by calculating changes in paleoproductivity, diversity and paleobiogeography ~26 to 2 Ma, which includes the progressive closure of the Central American Seaway. Three hypotheses were tested: (1) Paleoproductivity values prior to closure of the Central American Seaway are similar in both the Caribbean and equatorial Pacific and then diverge by the time of early shoaling events; (2) Diversity values of benthic foraminifera prior to the closure of the Central American Seaway were similar in the Caribbean and EEP, and had changed by the time of early shoaling; and (3) during …

Investigation Of The Lead Isotope Signatures Of Marine Sediments In Relation To The Lead Isotope Signatures Of Northern Andean Ores, Kimberly D. Beck

FIU Electronic Theses and Dissertations

Lead isotope ratios of ores and igneous rocks in the Central and Southern Andes show a large-scale geographic pattern related to magmatic source processes. This pattern changes in the Northern Andes for reasons that are not well understood; this study is an investigation of potential causes of this change. Deep ocean sediment samples from the Nazca Plate were analyzed for ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb, and the data were compared with published data on central Andean ores and ores and igneous rocks from Ecuador. Lead isotopic compositions of the Nazca Plate sediments …

Paleoenvironments And Geochemical Signals From The Late Barremian To The Middle Aptian In A Tethyan Marginal Basin, Northeast Spain: Implications For Carbon Sequestration In Restricted Basins, Yosmel Sanchez Hernandez Mr.

FIU Electronic Theses and Dissertations

The hallmark of oceanic anoxic event 1a (OAE1a) (early Aptian ~125 Ma) corresponds to worldwide deposition of black shales with total organic carbon (TOC) content > 2% and a d¹³C positive excursion up to ~5‰. OAE1a has been related to large igneous province volcanism and dissociation of methane hydrates during the Lower Cretaceous. However, the occurrence of atypical, coeval and diachronous organic-rich deposits associated with OAE1a, which are also characterized by positive spikes of the d¹³C in epicontinental to restricted marine environments of the Tethys Ocean, indicates localized responses decoupled from complex global forcing factors.

The present …

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 …

Hydrogeophysical Characterization Of Anisotropy In The Biscayne Aquifer Using Geophysical Methods, Albert Yeboah-Forson

FIU Electronic Theses and Dissertations

The anisotropy of the Biscayne Aquifer which serves as the source of potable water for Miami-Dade County was investigated by applying geophysical methods. Electrical resistivity imaging, self potential and ground penetration radar techniques were employed in both regional and site specific studies. In the regional study, electrical anisotropy and resistivity variation with depth were investigated with azimuthal square array measurements at 13 sites. The observed coefficient of electrical anisotropy ranged from 1.01 to 1.36. The general direction of measured anisotropy is uniform for most sites and trends W-E or SE-NW irrespective of depth. Measured electrical properties were used to estimate …

Analyzing Tidal Fluctuations In The Big Pine Key Freshwater Lens With Time-Lapse Resistivity, Nicole M. Tucker

FIU Electronic Theses and Dissertations

The tidal influence on the Big Pine Key saltwater/freshwater interface was analyzed using time-lapse electrical resistivity imaging and shallow well measurements. The transition zone at the saltwater/freshwater interface was measured over part of a tidal cycle along three profiles. The resistivity was converted to salinity by deriving a formation factor for the Miami Oolite. A SEAWAT model was created to attempt to recreate the field measurements and test previously established hydrogeologic parameters. The results imply that the tide only affects the groundwater within 20 to 30 m of the coast. The effect is small and caused by flooding from the …

Mineral Chemistry And Origin Of The Olivine-Rich Zone Of The Palisades Sill, Kevin Xavier Chau

FIU Electronic Theses and Dissertations

The Palisades Sill contains an olivine-rich zone that has attracted scientific attention for over one hundred years. Despite the amount of focus, a definitive explanation for the origin of this layer has not been reached. Through the use of detailed petrographic analyses and electron microscopy, the aim of this study was to collect data on mineral phases from the Palisades Sill in order to better understand the history. Extremely broad ranges in mineral compositions indicate that the olivine-rich zone evolved through in situ equilibrium crystallization, implying that it was injected once the main body of the sill had already been …

Quantifying The Effects Of Temperature And Concentration On Variable-Density Flow In Numerical Modeling Of Groundwater Systems : Implications For Predictive Uncertainty And Data Collection, Alyssa Marie Dausman

FIU Electronic Theses and Dissertations

Groundwater systems of different densities are often mathematically modeled to understand and predict environmental behavior such as seawater intrusion or submarine groundwater discharge. Additional data collection may be justified if it will cost-effectively aid in reducing the uncertainty of a model's prediction. The collection of salinity, as well as, temperature data could aid in reducing predictive uncertainty in a variable-density model. However, before numerical models can be created, rigorous testing of the modeling code needs to be completed. This research documents the benchmark testing of a new modeling code, SEAWAT Version 4. The benchmark problems include various combinations of density-dependent …

Determining Magmatic Processes From Analysis Of Phenocrysts And Gabbroic Xenoliths Contained In Calbuco Andesites, Tiffany Sperry Horst

FIU Electronic Theses and Dissertations

Calbuco Volcano, in Southern Chile, has eruptive products of predominantly andesitic hornblende-bearing lava. A purpose of this work is to understand magmatic processes and how Calbuco magma chemistry is related to the explosive volcanic character. Calbuco lava has a mineral assemblage of plagioclase, hornblende, orthopyroxene, clinopyroxene, olivine, and magnetite and entrained gabbroic xenoliths with the same mineral assemblage. The presence of hornblende is evidence for dissolved water in the magma. Detailed petrographic/textural analysis has been done using petrographic microscopy and back-scattered electron imaging (BSE); geochemical analysis by electron microprobe (EPMA). Major findings include 1) that hornblende and hornblende-bearing gabbroic cumulates …

Origin Of The Grande Ronde Formation Flows, Columbia River Flood Basalt Group, Sedelia Rodriguez Durand

FIU Electronic Theses and Dissertations

Lavas belonging to the Grande Ronde Formation (GRB) constitute about 63% of the Columbia River Basalt Group (CRBG), a flood basalt province in the NW United States. A puzzling feature is the lack of phenocrysts (< 5%) in these chemically evolved lavas. Based mainly on this observation it has been hypothesized that GRB lavas were nearly primary melts generated by large-scale melting of eclogite. Another recent hypothesis holds that GRB magmas were extremely hydrous and rose rapidly from the mantle such that the dissolved water kept the magmas close to their liquidi. I present new textural and chemical evidence to show that GRB lavas were neither primary nor hydrous melts but were derived from other melts via efficient fractional crystallization and mixing in shallow intrusive systems. Texture and chemical features further suggest that the melt mixing process may have been exothermic, which forced variable melting of some of the existing phenocrysts.

Finally, reported here are the results of efforts to simulate the higher pressure histories of GRB using COMAGMAT and MELTS softwares. The intent was to evaluate (1) whether such melts could be derived from primary melts formed by partial melting of a peridotite source as an alternative to the eclogite model, or if bulk melting of eclogite is required; and (2) at what pressure …

Paleolimnological Investigation Of Recent Sediments From Lake Monroe, Florida, Usa., Bryan P. Carroll

FIU Electronic Theses and Dissertations

Sediments recovered in October 2003 from Lake Monroe, a hypereutrophic lake in central Florida, have been sub-sampled and analyzed for δ¹³C, δ¹⁵N, TC, TIC, TOC, and TN. A chronology of bulk sediment and nutrient accumulation was established by radiometric analyses (²¹⁰Pb, ¹³⁷Cs, and ¹⁴C), to aid in evaluating spatial and temporal patterns within the lake since development in the watershed began. A continuous 100- year sediment record from Lake Monroe shows significant changes in production, sedimentation, and nutrient abundance following land settlement in the mid 1800's. Sediment nutrient and isotopic analyses demonstrate …

Effect Of Scaling On Hydraulic Conductivity In A Karst Aquifer, Vincent J. Difrenna

FIU Electronic Theses and Dissertations

Hydraulic conductivity was determined for samples from the Biscayne Aquifer in Miami Florida at bench and field scales. Hydraulic conductivity values obtained were examined for increase due to scale and for anisotropy. Bench scale testing was performed on Key Largo Limestone cubes for total porosity, effective porosity, and hydraulic conductivity. Total porosity was determined by drying and weighing, while effective porosity was determined by submersion. Hydraulic conductivity was determined in a permeameter for each axis of each cube. Field scale testing of hydraulic conductivity was performed with slug tests in the Miami Oolite Formation at the Homestead General Airport. Aquifer …

Characterizing Fracture Distribution In Layered Rocks Using Geographic Information System-Based Techniques, Kajari Ghosh

FIU Electronic Theses and Dissertations

Fractures are discrete planar features that are heterogeneously distributed throughout the earth's upper crust. Methods commonly used to quantify fracture populations typically yield singular values/indexes for the attribute of interest. These values are useful in characterizing the bulk properties of a fracture population, but are unable to address the inherent spatial heterogeneities of the fracture network.

This study explores techniques to map fractures and capture the spatial heterogeneity of fracture networks within a Geographic Information System (GIS). The study was performed on exposures of the intensely fractured Monterey Formation in Santa Barbara, California. Results of the GIS-based spatial analysis provide …

Melt Inclusions From Volcan De Colima, Mexico: Complex Examples Of Magmatic Differentiation, Zachary D. Atlas

FIU Electronic Theses and Dissertations

Melt inclusions are minute magma bodies trapped within growing crystals. Their chemical compositions are useful in deciphering pre-eruptive conditions and magma evolution. The present study examined melt inclusions trapped in phenocrysts from the 3^rd and 4^th magmatic cycles (1869-1988) at Volcan de Colima, Mexico. Melt inclusions have highly evolved chemical compositions: 65-77% SiO₂, >12% A1₂O₃, 3-6% Na₂O and K₂0 and less than 5.5% Fe and Mg. Major element compositions suggest that they are strongly differentiated magmas controlled by fractionation of plagioclase, opx, cpx and hornblende. Water concentrations were …

Geochemical Variation Among Small Eruptive Centers In The Central Svz Of The Andes : An Evaluation Of Subduction, Mantle And Crustal Influences, Murong Sun

FIU Electronic Theses and Dissertations

Subduction zone magmatism is an important and extensively studied topic in igneous geochemistry. Recent studies focus on from where arc magmas are generated, how subduction components (fluids or melts) are fluxed into the source of the magmas, and whether or how the subduction components affect partial melting processes beneath volcanic arcs at convergent boundaries.

At 39.5°S in the Central Southern Volcanic Zone of the Andes, Volcano Villarrica is surrounded by a suite of Small Eruptive Centers (SEC). The SECs are located mostly to the east and northeast of the stratovolcano and aligned along the Liquine - Ofqui Fault …

Ammonite Biostratigraphy, Lithofacies Variations, And Paleoceanographic Implications For Barremian-Aptian Sequences Of Northeastern Mexico, Ricardo Barragan

FIU Electronic Theses and Dissertations

Two Barremian-Aptian sequences studied in Durango and Nuevo Leon States, northeastern Mexico include three lithic units which have been described as the Cupido Formation of Barremian-early Early Aptian age, its lateral equivalent, the Lower Tamaulipas Formation, and the La Pena Formation extending through the early Albian.

The present work improves the existing ammonite Aptian biozonation by considering constraints associated with a discontinuous spatial and temporal record of the different taxa within the La Pena Formation.

Four ammonite biozones are established: 1) The Dufrenoyia justinae Zone for the late Early Aptian, 2) The Burckhardtites nazasensis/Rhytidoplites robertsi Zone for the middle Aptian, …

Theoretical Analysis Of Cross Joint Geometries And Their Classification, Taixu Bai

FIU Electronic Theses and Dissertations

Joints as opening-mode fractures play important roles as indicators of tectonic stress fields and as pathways for underground fluid flow. This thesis analytically investigates the relationships among cross joint geometry, orientations and ratios of remote principal stresses, and fluid pressure. Results show that main trends of cross joints are perpendicular to the least far field stresses during cross joint formation, and cross joint paths can be used to determine relative magnitudes of remote principal stresses. Based on the theoretical derivation, cross joint geometries are grouped into five main categories: curving-parallel, curving-perpendicular, quasi-curving-parallel, quasi-curving-perpendicular and non-curving geometries. By introducing the concepts …

Investigation Of Spatial Patterns Of Ground-Water Exchange With Lakes, Using A Three-Dimensional Numerical Model, Indranil Bandopadhyay

FIU Electronic Theses and Dissertations

Hydrogeologic variables controlling groundwater exchange with inflow and flow-through lakes were simulated using a three-dimensional numerical model (MODFLOW) to investigate and quantify spatial patterns of lake bed seepage and hydraulic head distributions in the porous medium surrounding the lakes. Also, the total annual inflow and outflow were calculated as a percentage of lake volume for flow-through lake simulations. The general exponential decline of seepage rates with distance offshore was best demonstrated at lower anisotropy ratio (i.e., Kh/Kv = 1, 10), with increasing deviation from the exponential pattern as anisotropy was increased to 100 and 1000. 2-D vertical section models constructed …