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2020

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Articles 391 - 405 of 405

Full-Text Articles in Geology

Copper And Gold In Vapors And Liquids As A Function Of Hcl At 700°C And 100 Mpa, Corrie A. Lucchesi Jan 2020

Copper And Gold In Vapors And Liquids As A Function Of Hcl At 700°C And 100 Mpa, Corrie A. Lucchesi

Graduate Research Theses & Dissertations

Porphyry ore deposits are major sources of copper (Cu) and gold (Au) and form when a magmatic volatile phase (MVP) exsolves from a porphyritic intermediate to felsic melt and transports metals to surrounding country rock where they precipitate in an ore zone. There is a consensus that the chloride concentration of the MVP has a direct relationship to the concentration of Cu and Au in the MVP, but the role of dissolved HCl on Cu and Au concentrations has not been addressed. It is hypothesized that increasing HCl concentrations in the MVP will result in higher concentrations of Cu and …

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Estimating Paleotemperatures In The Amundsen Sea For The Last 620,000 Years Through Diatom Morphometrics (Iodp Expedition 379), Joseph Robert Mastro Jan 2020

Estimating Paleotemperatures In The Amundsen Sea For The Last 620,000 Years Through Diatom Morphometrics (Iodp Expedition 379), Joseph Robert Mastro

Graduate Research Theses & Dissertations

As global climate continues to rapidly change over the coming decades, West Antarctica will continue to be a significant area of concern due to its susceptibility to marine ice sheet collapse. Past collapses during Pleistocene interglacials have been hypothesized but uncertainty exists with respect to the precise timing of specific collapse events. Drill core samples collected from the Amundsen Sea continental rise during IODP Expedition 379 allow for analysis of a more continuous record of Pleistocene glacial-interglacial cycles. Here we report paleotemperature estimates from the Amundsen Sea spanning the last 620 kyr with the objective of identifying likely late Pleistocene …

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An Integrated Wellbore Stability Study To Mitigate Expensive Wellbore Instability Problems While Drilling Into Zubair Shale/Sand Sequence, Southern Iraq, Ahmed Khudhair Abbas Jan 2020

An Integrated Wellbore Stability Study To Mitigate Expensive Wellbore Instability Problems While Drilling Into Zubair Shale/Sand Sequence, Southern Iraq, Ahmed Khudhair Abbas

Doctoral Dissertations

”The Zubair Formation is the most prolific reservoir in Iraq, which is comprised of sandstones interbedded with shale sequences. Due to the weak nature of the shale sequence, the instability of a wellbore is one of the most critical challenges that continuously appears during drilling across this formation. Historically, over 90% of wellbore problems in the Zubair Formation were due to wellbore instability. Problems associated with wellbore instability, such as tight hole, shale caving, stuck logging tools along with subsequent fishing, stuck pipe, and sidetracking result in increasing the non-productive time. This non-productive time has cost an enormous amount of …

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History Of Natural And Anthropogenic Activities In Lake Izabal, Eastern Guatemala: Using Geochemical Evidence To Record Recent Contamination, Elisandra Hernandez Jan 2020

History Of Natural And Anthropogenic Activities In Lake Izabal, Eastern Guatemala: Using Geochemical Evidence To Record Recent Contamination, Elisandra Hernandez

Doctoral Dissertations

”Water is essential for human subsistence. Stable freshwater supplies are needed as a source of food, drinking water, for transportation, recreation and economic development. Despite their recognized importance, anthropogenic activities have altered freshwater ecosystems around the world. Lake Izabal is the habitat for diverse aquatic species of flora and fauna, some of which are endemic and endangered. Its importance notwithstanding, anthropogenic activities developed in Lake Izabal’s catchment in recent years have compromised its status. This study used paleolimnological techniques to link past and recent anthropogenic activities such as mining operations and recent tilapia aquaculture. Relative abundances and concentrations of Pb, …

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Predictive Geohazard Mapping Using Lidar And Satellite Imagery In Missouri And Oklahoma, Usa, Olufeyisayo B. Ososami Jan 2020

Predictive Geohazard Mapping Using Lidar And Satellite Imagery In Missouri And Oklahoma, Usa, Olufeyisayo B. Ososami

Doctoral Dissertations

”Light Detection and Ranging (LiDAR) and satellite imagery have become the most utilized remote sensing technologies for compiling inventories of surficial geologic conditions. Point cloud data obtained from multi-spectral remote sensing methods provide a detailed characterization of the surface features, in particular, the detailed surface manifestations of underlying geologic structures. When combined, point clouds eliminate bias from visual inconsistencies and/or statistical values. This research explores the competence of point clouds derived from LiDAR and Unmanned Aerial Systems (UAS) as a predictive tool in evaluating various geohazards. It combines these data sets with other remote sensing techniques to evaluate the sensitivity …

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A Broad Iceland Plume Associated With Two Phase Transitions At The 660 Km Discontinuity: Constraints From Receiver Functions, Dan Wang Jan 2020

A Broad Iceland Plume Associated With Two Phase Transitions At The 660 Km Discontinuity: Constraints From Receiver Functions, Dan Wang

Doctoral Dissertations

"In spite of the fact that Iceland is frequently regarded as the archetypal example of mantle plumes, the existence, depth extent, origin, dimension and excess temperature of the hypothesized plume remain enigmatic and hotly debated. The controversy mostly originates from the limited vertical resolution of seismic tomography techniques and the associated uncertainty in the depth and lateral extents of the lower wavespeed anomaly. Here we utilize a robust receiver-function-based technique to image the topography of the 410 and 660 km discontinuities bordering the mantle transition zone beneath Iceland and surrounding oceanic regions, and construct thermal and seismic wavespeed models of …

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Seismological Investigations Of Lithospheric Structure Beneath The East African Rift System And The Kalahari Craton, Tuo Wang Jan 2020

Seismological Investigations Of Lithospheric Structure Beneath The East African Rift System And The Kalahari Craton, Tuo Wang

Doctoral Dissertations

"In spite of numerous geophysical studies have been conducted in East African Rift System and Southern Africa, the structure and evolution of the crust and upper mantle are still controversial. In this study, we applied multiple seismological techniques to investigate the structure in the crust and uppermost mantle beneath the East African Rift System and Kalahari Craton in southern Africa. First, the technique of ambient noise tomography was applied to image shear wave velocity model from surface to the depth of 40 km beneath the Malawi and Luangwa rift zones. For the first time, a high-resolution 3-D shear wave velocity …

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Anatomy Of The Magmatic Plumbing System Of Los Humeros Caldera (Mexico): Implications For Geothermal Systems., Federico Lucci, Gerardo Carrasco-Nuñez, Federico Rossetti, Thomas Theye, John C. White, Stefano Urbani, Hossein Azzizi, Yosihiro Asahara, Guido Giordano Jan 2020

Anatomy Of The Magmatic Plumbing System Of Los Humeros Caldera (Mexico): Implications For Geothermal Systems., Federico Lucci, Gerardo Carrasco-Nuñez, Federico Rossetti, Thomas Theye, John C. White, Stefano Urbani, Hossein Azzizi, Yosihiro Asahara, Guido Giordano

EKU Faculty and Staff Scholarship

Understanding the anatomy of magma plumbing systems of active volcanoes is essential not only for unraveling magma dynamics and eruptive behaviors but also to define the geometry, depth, and temperature of the heat sources for geothermal exploration. The Pleistocene–Holocene Los Humeros volcanic complex is part of the eastern Trans- Mexican Volcanic Belt (central Mexico), and it constitutes one of the most important exploited geothermal fields in Mexico with ca. 90MWof produced electricity. With the aim to decipher the anatomy (geometry and structure) of the magmatic plumbing system feeding the geothermal field at Los Humeros, we carried out a field-based petrological …

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Paleoecology Of Bivalves In The Carmel Formation (Middle Jurassic, Bajocian) Of Utah, Evan L. Shadbolt Jan 2020

Paleoecology Of Bivalves In The Carmel Formation (Middle Jurassic, Bajocian) Of Utah, Evan L. Shadbolt

Senior Independent Study Theses

The Carmel Formation of the Middle Jurassic has many mysteries. One of these enigmas is its bivalves. The formation contains the famous oyster balls called ostreoliths. Despite bivalves making up 80 percent of the fossils found in the Carmel Formation, it is not understood how the bivalves lived in this community. The formation is located in southwestern and central Utah. It was deposited when an epicontinental seaway covered most of Utah. The paleoclimate of Utah was hot and dry, which meant that the environment was evaporite heavy. This also meant that the seawater at the southernmost extent of the seaway …

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Hydromorphological Changes Of Chi River, Mueang District, Khon Kaen Province, Pawat Wattanachareekul Jan 2020

Hydromorphological Changes Of Chi River, Mueang District, Khon Kaen Province, Pawat Wattanachareekul

Chulalongkorn University Theses and Dissertations (Chula ETD)

This thesis focuses on the analysis of hydrology coupled with geomorphology for river management such as flood mitigation and river restoration. Morphological Quality Index (MQI) is used for assessing hydro-morphological conditions from part of the Chi River (67 km long) at Khon Kaen province, a major river in north-eastern Thailand. This study area has been suffering from unexpected and repeated flooding. MQI is applied to evaluate the degree of hydro-morphological alteration in terms of relative scores (from 0 to 1). Basically, in case that MQI score equals 1, it means the area has no any alteration. On the other hand, …

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Geology And Petrochemistry Of Volcanic Rocks In The Lam Sonthi Area, Lop Buri Province, Saowaphap Uthairat Jan 2020

Geology And Petrochemistry Of Volcanic Rocks In The Lam Sonthi Area, Lop Buri Province, Saowaphap Uthairat

Chulalongkorn University Theses and Dissertations (Chula ETD)

Lam Sonthi area is in Lop Buri province, central Thailand. Stratigraphically, the geology of the area consists of five rocks units; Unit I: Khao Ruak siltstone which is correlated to Khao Luak Formation (Early Permian), Unit II: Khao Phaeng Ma conglomerate, Unit III: Khao Ruak volcanics, Unit IV: Lam Sonthi polymictic conglomerate, and Unit V: Kuttaphet sandstone which is correlated to Phu Kradung Formation (Early Jurassic). In addition, the volcanic rocks, which are named as Kuttaphet volcanics and Khok Khli volcanics, could be found in the top of Unit IV as the polymictic intermediate breccia. Petrographic classification identifies the volcanic …

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Mineral Inclusions In Sapphire From Basalt - Related Deposit In Southern Vietnam, Vu Doan Thi Anh Jan 2020

Mineral Inclusions In Sapphire From Basalt - Related Deposit In Southern Vietnam, Vu Doan Thi Anh

Chulalongkorn University Theses and Dissertations (Chula ETD)

Sapphires in Southern Vietnam have been discovered in alluvial deposit derived from Cenozoic basalts. Sample collections for this study were taken from the most significant gem fields including Pleiku, Dak Nong, Di Linh, Binh Thuan, and Krong Nang. Several syngenetic mineral inclusions in these sapphires were classified as alkali feldspar, zircon, ferrocolumbite, pyrochlore, and iron oxides. Mineral chemical characteristics of these inclusions appearred to have evolved from alkaline felsic suite. Oxide mineral inclusions occurred in sapphire included hercynite, wüstite, and ilmenite. Ilmenite ranged in composition between Il49-54He34-40Mt7-10 and Il24-30He36-38Mt35-40 falling in ilmenite-hematite series. Wüstite with nonstoichiometry, (Fe2+0.3-0.9)(Ti3+<0.179Al3+≤0.6Cr3+<0.1 Fe3+≤0.46)£≤0.23O, was usually associated with hercynite inclusion clearly indicating cogenetic sapphire formation. Wüstite and sapphire appeared to have formed from the breakdown reaction of hercynite (hercynite = sapphire+wüstite). Titanohematite series and titanomagnetite series might have crystallized during iron-titanium reequilibration via subsolidus exsolution. U-Pb geochronology of zircon inclusion in these sapphires yielded between 35.5 ± 1.6 Ma (~35 Ma) and 14.73 ± 0.29 Ma (~15 Ma) for Krong Nang sapphire, 5.94 ± 0.13 Ma (~6 Ma) for Binh Thuan and Dak Nong sapphire, and 5.491 ± 0.077 Ma (~5.5 Ma) for Di Linh sapphire. These age constraints relate to the main Cenozoic basaltic eruptions in this region. Crystallization temperature of sapphire formation was estimated at about 561- 7810C using Ti-in-zircon thermometry.

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Stratigraphy And Volcanic Facies In Khao Noi Area, Tha Takiap District, Chachoengsao Province, Amporn Chaikam Jan 2020

Stratigraphy And Volcanic Facies In Khao Noi Area, Tha Takiap District, Chachoengsao Province, Amporn Chaikam

Chulalongkorn University Theses and Dissertations (Chula ETD)

The Khao Noi volcanics is in Tha Takiap district, Chachoengsao province, eastern Thailand. This volcanics is a part of the Lampang volcanic belt, a potential host rocks for mineralizations, especially gold and antimony epithermal style deposits. Based on field investigation, drill core logging, and petrographic study, the Khao Noi host volcanic sequence has a thickness of at least 150 meters. The sequence can be divided into three units, namely 1) Sedimentary unit (Unit 1), 2) Mafic-intermediate volcanic unit (Unit 2), and 3) Felsic volcanic unit (Unit 3). Unit 1 forms as a basement of the Khao Noi volcanic sequence and …

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Relating Sonic Velocities, Minimum Horizontal Stress, And Natural Fracture Distribution To Stimulation Efficiency During Completion Of The Marcellus Shale Mip-3h Unconventional Well, West Virginia, Usa, Kaitlin Gayle Evans Jan 2020

Relating Sonic Velocities, Minimum Horizontal Stress, And Natural Fracture Distribution To Stimulation Efficiency During Completion Of The Marcellus Shale Mip-3h Unconventional Well, West Virginia, Usa, Kaitlin Gayle Evans

Graduate Theses, Dissertations, and Problem Reports (ETD)

Log data from the Marcellus Shale Energy and Environment Laboratory (MSEEL) was acquired along the lateral of the MIP-3H well. This unconventional shale-gas well was completed within the Marcellus Shale just above the Cherry Valley Limestone, a thin limestone member separating organic rich units of the Marcellus. The geomechanical moduli, Poisson’s Ratio (PR) and Young’s Modulus (YME), were generated using compressional and shear sonic logs to indicate zones of increasing brittleness for each of the 28 stages along the 6124 ft. (1867m) horizontal lateral. Brittle reservoir rock is more readily fractured during hydraulic stimulation than more malleable rock. Stages with …

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Reservoir Characterization And Static Earth Modeling For Potential Co2 Storage In Upper Pennsylvanian Cyclothems Of Midcontinent, Usa, Valerie Lynn Smith Jan 2020

Reservoir Characterization And Static Earth Modeling For Potential Co2 Storage In Upper Pennsylvanian Cyclothems Of Midcontinent, Usa, Valerie Lynn Smith

Graduate Theses, Dissertations, and Problem Reports (ETD)

This dissertation details the estimation of CO2 storage volume using reservoir characterization and the building of static earth models in two papers: 1) for Sleepy Hollow Field in Red Willow County, Nebraska and, 2) for Huffstutter Field, Phillips County, Kansas. These models are used to obtain estimates of CO2 storage capacity in stacked carbonate intervals of the Pennsylvanian Lansing and Kansas City groups (LKC). The LKC constitutes a regional succession of interbedded carbonates and shales. Located over the Cambridge Arch of Nebraska, these interbedded units were evaluated for carbon storage potential. Understanding the occurrence of carbonate porosity among …

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