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2015

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Articles 841 - 870 of 1152

Full-Text Articles in Earth Sciences

Dynamic Triggering In The Coso Geothermal Field, 2004-2013, Richard A. Alfaro-Diaz Jan 2015

Dynamic Triggering In The Coso Geothermal Field, 2004-2013, Richard A. Alfaro-Diaz

Open Access Theses & Dissertations

We take advantage of EarthScope’s USArray Transportable Array (TA), regional seismic networks to investigate 154 M ≥ 7 earthquakes over a ten-year period (2004- 2013), in search of remotely triggered seismicity within the continental United States. We conduct an automated search to detect high frequency signals (which may indicate triggering of small local earthquakes) using a time window of 5 hours before and after each mainshock. The automated detection applies a short-term average (STA) to long-term-average (LTA) algorithms, to create a catalogue of detections. Using the catalog we search for an increase in detection rates after each main-shock. Sharp increases …


Evaluating Methods Of Field-Based 3d Visualization And Their Application To Mapping Metamorphic Terranes: An Example From The Panamint Mountains, California, Jade Ashley Brush Jan 2015

Evaluating Methods Of Field-Based 3d Visualization And Their Application To Mapping Metamorphic Terranes: An Example From The Panamint Mountains, California, Jade Ashley Brush

Open Access Theses & Dissertations

Field geology has traditionally relied on 2D, paper-based workflows, but digital mapping techniques are rapidly replacing these outdated methods because they allow for more efficient and accurate mapping. This research applies digital mapping techniques and two terrestrially-based 3D visualization technologies, photogrammetry and Light Detection and Ranging (LiDAR), to the study of metamorphic terranes in the Panamint Mountains, California. This study reports on the spatial accuracy of TINs (triangulated irregular networks) generated from both photogrammetry and ground-based LiDAR using a terrestrial laser scanner (TLS) and discusses how spatial accuracy can be increased. Two levels of comparison were used to test spatial …


Understanding The Contractional History Of Surprise Canyon, California Through Digital Field Mapping, 3d Modeling, And U-Pb Zircon Geochronology, Joshua A. Cobb Jan 2015

Understanding The Contractional History Of Surprise Canyon, California Through Digital Field Mapping, 3d Modeling, And U-Pb Zircon Geochronology, Joshua A. Cobb

Open Access Theses & Dissertations

Detailed digital mapping of lower-middle Surprise Canyon has revealed a more complex structure than previously interpreted. Rock units derived from the metamorphosed equivalents of the Pahrump Group exposed in Surprise Canyon display juxtapositions inconsistent with stratigraphic variations suggested in previous studies. This study proposes a contractional history of the central Panamint Mountains defined by two kinematically distinct and geochronologically constrained deformation events. D1 is characterized by a shallow dipping, NNW striking L and LS tectonite fabric ubiquitously observed in all metasedimentary and basement units. F1 folds are mesoscopic in scale and isoclinal with an axial planar S1 foliation. A prominent …


Quantifying Weathering Rates On Tropical Volcanic Basse-Terre Island, French Guadeloupe: Insights From U-Series Isotopes In Weathering Rinds, Jacqueline Engel Jan 2015

Quantifying Weathering Rates On Tropical Volcanic Basse-Terre Island, French Guadeloupe: Insights From U-Series Isotopes In Weathering Rinds, Jacqueline Engel

Open Access Theses & Dissertations

Weathering of volcanic rocks plays many important roles at Earth’s surface such as modifying landscapes, providing nutrients to soil, and regulating atmospheric CO2. U-series isotopes (e.g. 238U-234U-230Th and 232Th) have been established as a chronometer used to constrain the formation rates of weathering rinds in tropical island environments. Here, U-series isotopes and major element concentrations were analyzed in two basaltic-andesite weathering rinds collected from the Deshaies watershed located in the northern, relatively dry (mean annual precipitation (MAP) = 1800 mm) region of tropical Basse-Terre Island, Guadeloupe. The two clasts are referred to as clasts AN-14-7.5 and AN-14-7.6. Elemental mobility trends …


Crustal Structure Beneath The Eastern Nepal Himalayas And Southern Tibet From Receiver Function Analysis, Arjun Sharma Neupane Jan 2015

Crustal Structure Beneath The Eastern Nepal Himalayas And Southern Tibet From Receiver Function Analysis, Arjun Sharma Neupane

Open Access Theses & Dissertations

The Himalayas are the results of continental collision between the Indian plate and the Eurasian plate and serve as a natural site to study the physical causes and process of mountain building. The crustal structure beneath the Himalayas has been subject to numerous geophysical studies and the variation in the velocity structure across the Himalayan region suggests significant differences in the crustal structure between the southern and northern portion in that region. In this research, a P receiver function analysis has been conducted on data collected for 14 years (2000-2014) from 211 different stations in Eastern Nepal and Southern Tibet, …


Temporal Evolution Of Basal Water Pressure And Ice Velocity Along A 50 Km Flow Line Transect Of Western Greenland, Patrick Wright Jan 2015

Temporal Evolution Of Basal Water Pressure And Ice Velocity Along A 50 Km Flow Line Transect Of Western Greenland, Patrick Wright

Graduate Student Theses, Dissertations, & Professional Papers

The gradient in hydraulic potential at the ice-bedrock interface beneath the Greenland Ice Sheet (GrIS) dictates the routing and energetics of subglacial water, thereby influencing drainage system characteristics and sliding dynamics. In the ablation zone of the GrIS, a high relief bed and gradients in water pressure in an active subglacial drainage system potentially play a complex role in dictating the hydraulic potential field. Here we present a suite of water pressure measurements collected within thirteen boreholes along a 46 km transect on the western GrIS in order to investigate the sensitivity of the potential gradient field to seasonal evolution …


Petrography And Geochemistry Of The Kamlial Formation, Southwestern Kohat Plateau, Pakistan: Implications For Paleoclimate Of The Western Himalayas, Kafayat Ullah, Mohammad Arif, Muhammad Tahir Shah Jan 2015

Petrography And Geochemistry Of The Kamlial Formation, Southwestern Kohat Plateau, Pakistan: Implications For Paleoclimate Of The Western Himalayas, Kafayat Ullah, Mohammad Arif, Muhammad Tahir Shah

Turkish Journal of Earth Sciences

The Middle to Late Miocene Kamlial Formation that largely consists of sandstone and interbedded clay/mudstone sequences is exposed in the southwestern part of the Kohat plateau, which constitutes the westernmost extension of the Himalayan Foreland Basin. Whereas the sandstone is gray to brownish gray, fine- to medium-grained, and mostly thick-bedded, the interbedded clay/mudstone sequence is brownish gray to maroon red and occurs as continuous beds as well as lenses. Some mudstone/clay beds are bioturbated and seem to be pedogenic surfaces. Results of geochemical investigation of fresh (unaltered) representative sandstone and mudstone samples from three different sections of the formation in …


Petrography And Geochemistry Of Pharaonic Sandstone Monuments In Tall San Al Hagr, Al Sharqiya Governorate, Egypt: Implications For Provenance And Tectonic Setting, Samir Mahmoud Zaid, Oussama El Badry, Fatma Ramadan, Mahmoud Mohamed Jan 2015

Petrography And Geochemistry Of Pharaonic Sandstone Monuments In Tall San Al Hagr, Al Sharqiya Governorate, Egypt: Implications For Provenance And Tectonic Setting, Samir Mahmoud Zaid, Oussama El Badry, Fatma Ramadan, Mahmoud Mohamed

Turkish Journal of Earth Sciences

Petrographic and major and trace element compositions of Tanis sandstones from Tall San Al Hagr, Al Sharqiya Governorate, Egypt, have been investigated to determine their source, provenance, intensity of paleoweathering of the source rocks, and tectonic setting. Tanis sandstones are yellowish brown in color, siliceous, partly calcareous, and originated from sands deposited in fluvial channels. Texturally, Tanis sandstones are medium- to very coarse-grained, mature, and moderately sorted. Scarcity of feldspars indicates that the sandstone is extensively recycled from a distant source. Their average modal composition (Q99.75F0.03L0.22) classifies them as quartz arenites (quartzite), which is consistent with the geochemical study. Chemical …


Petrography And Palynology Of Late Oligocene And Middle Miocene Coals In The Gelibolu Peninsula, Nw Turkey, Ferdi̇ Demi̇rtaş, Mustafa Bozcu, Erdal Koşun, Mehmet Serkan Akki̇raz Jan 2015

Petrography And Palynology Of Late Oligocene And Middle Miocene Coals In The Gelibolu Peninsula, Nw Turkey, Ferdi̇ Demi̇rtaş, Mustafa Bozcu, Erdal Koşun, Mehmet Serkan Akki̇raz

Turkish Journal of Earth Sciences

In this study, coal samples from two different coal zones located close to each other were examined. They occur in the Late Oligocene Osmancık and Miocene Gazhanedere formations in the Gelibolu peninsula, in the SW part of the Thrace Basin (NW Turkey). This paper focuses on the organic-petrographic composition and depositional conditions of the two coal zones by using coal petrography, including maceral ratios, and palynology. The maceral composition of the Oligocene coal samples is similar to that of the Miocene coal samples. The coal samples from both locations are characterized by a high content of huminite group macerals, ranging …


Magmatic Plumbing At Lucky Strike Volcano Based On Olivine-Hosted Melt Inclusion Compositions, V. D. Wanless, A. M. Shaw, M. D. Behn, S. A. Soule, J. Escartín, C. Hamelin Jan 2015

Magmatic Plumbing At Lucky Strike Volcano Based On Olivine-Hosted Melt Inclusion Compositions, V. D. Wanless, A. M. Shaw, M. D. Behn, S. A. Soule, J. Escartín, C. Hamelin

Geosciences Faculty Publications and Presentations

Here we present volatile, major, and trace element concentrations of 64 olivine-hosted melt inclusions from the Lucky Strike segment on the mid-Atlantic ridge. Lucky Strike is one of two locations where a crustal melt lens has been seismically imaged on a slow-spreading ridge. Vapor-saturation pressures, calculated from CO2 and H2O contents of Lucky Strike melt inclusions, range from approximately 300-3000 bars, corresponding to depths of 0.5-9.9 km below the seafloor. Approximately 50% of the melt inclusions record crystallization depths of 3-4 km, corresponding to the seismically imaged melt lens depth, while an additional ∼35% crystallize at depths …


Reductions Of Wheat Yield And Yield Components And Nitrogen Loss Following Frozen Soil Nitrogen Applications, Carrie Ann Knott, Edwin L. Ritchey, Lloyd W. Murdock Jan 2015

Reductions Of Wheat Yield And Yield Components And Nitrogen Loss Following Frozen Soil Nitrogen Applications, Carrie Ann Knott, Edwin L. Ritchey, Lloyd W. Murdock

Plant and Soil Sciences Research Report

Most wheat producers in Kentucky apply nitrogen (N) as a split application. The first N increment is applied when wheat plants begin actively growing (green-up) in late winter, which is typically in mid- February between growth stages Feekes 2 to 3. The second N increment typically occurs in March when wheat is between Feekes 5 to 6. Many producers in Kentucky, especially Western Kentucky, have become accustomed to beginning first N applications in late January when the ground is frozen and the wheat is still dormant. This practice allows them to apply N to large acreages of wheat while avoiding …


Quality Of Water From Tile Drains In Fields Treated With Poultry Litter In Mclean County, Kentucky, E. Glynn Beck, Lisa Y. Blue, David A. Atwood Jan 2015

Quality Of Water From Tile Drains In Fields Treated With Poultry Litter In Mclean County, Kentucky, E. Glynn Beck, Lisa Y. Blue, David A. Atwood

Information Circular--KGS

Poultry litter (a mixture of feed, manure, and bedding material) is commonly used as a soil amendment to row-crop fields in western Kentucky. Because of feed additives, litter typically has elevated concentrations of contaminants, including metals and anions. These metals and anions can accumulate in the soil and therefore could be transported to surface water through drainage tiles. In order to assess water quality in tile drains, a pilot study was conducted in 2008 in McLean County, Kentucky, in which 10 tile drains and six drainage ditches were sampled for total metals and anions. Seven of the tile-drained fields were …


Comparison Of The Ground-Motion Attenuation Relationship Between The Wenchuan, China, Area And The Central And Eastern United States, Jiwei Feng, Zhenming Wang, Edward W. Woolery, Shanyou Li Jan 2015

Comparison Of The Ground-Motion Attenuation Relationship Between The Wenchuan, China, Area And The Central And Eastern United States, Jiwei Feng, Zhenming Wang, Edward W. Woolery, Shanyou Li

Report of Investigations--KGS

An Mw-7.9 earthquake occurred in Wenchuan, China, in 2008, along the Longmenshan Fault, which is located on the western border of the South China stable continental region. A detailed comparison of the Wenchuan ground-motion attenuation relationships with the relationships for the central and eastern United States (also a stable continental region) showed that the ground-motion prediction equation for the Wenchuan area is similar to those for the central and eastern United States. Thus, the strong-motion records from the Wenchuan earthquake can be used for constraining the ground-motion prediction equation and engineering analysis for the central and eastern United …


The Geologic Context Of Landslide And Rockfall Maintenance Costs In Kentucky, Bethany L. Overfield, Daniel I. Carey, Gerald A. Weisenfluh, Rebecca Wang, Matthew M. Crawford Jan 2015

The Geologic Context Of Landslide And Rockfall Maintenance Costs In Kentucky, Bethany L. Overfield, Daniel I. Carey, Gerald A. Weisenfluh, Rebecca Wang, Matthew M. Crawford

Report of Investigations--KGS

Kentucky Transportation Cabinet maintenance cost data for landslides and rockfalls were associated with geology along Kentucky roadways in a three-phase study. Work-order costs collected over 7 yr were divided into 1-mi segments, and the segment midpoints were assigned to geologic formation. Formations that were expensive to maintain were not necessarily those that were the most frequently repaired and vice versa. Costs and frequency of repair were greater in eastern and northern Kentucky, where slope and relief are greater than in other parts of the state and shale-bearing geologic units prevail.


Channel Morphology At A Meander Bend Chute Cutoff Partially Obstructed By Woody Debris, Drew Sobczak Jan 2015

Channel Morphology At A Meander Bend Chute Cutoff Partially Obstructed By Woody Debris, Drew Sobczak

Masters Theses

Field and flume experiments have examined the conceptual model for a meander bend in depth. Large woody debris piles are often associated with the development of a chute cutoff due to local aggradation and deflection of flow. This paper examines the bed morphology of a meander bend chute cutoff that is partially obstructed by woody debris. The bed morphology of the channel around the woody debris pile as well as the head of the cutoff are mapped. The pile is shielding the point bar immediately behind it and causing a narrow, deep channel on either side of the pile. The …


Molecular Level Characterization Of Diatom-Associated Biopolymers That Bind 234th, ²³³Pa, ²¹°Pb, And 7be In Seawater: A Case Study With Phaeodactylum Tricornutum, Chia-Ying Chuang, Peter H. Santschi, Chen Xu, Yuelu Jiang, Yi-Fang Ho, Patrick G. Hatcher Jan 2015

Molecular Level Characterization Of Diatom-Associated Biopolymers That Bind 234th, ²³³Pa, ²¹°Pb, And 7be In Seawater: A Case Study With Phaeodactylum Tricornutum, Chia-Ying Chuang, Peter H. Santschi, Chen Xu, Yuelu Jiang, Yi-Fang Ho, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

In order to investigate the importance of biogenic silica associated biopolymers on the scavenging of radionuclides, the diatom Phaeodactylum tricornutum was incubated together with the radionuclides Th-234, Pa-233, Pb-210, and Be-7 during their growth phase. Normalized affinity coefficients were determined for the radionuclides bound with different organic compound classes (i.e., proteins, total carbohydrates, uronic acids) in extracellular (nonattached and attached exopolymeric substances), intracellular (ethylene diamine tetraacetic acid and sodium dodecyl sulfate extractable), and frustule embedded biopolymeric fractions (BF). Results indicated that radionuclides were mostly concentrated in frustule BF. Among three measured organic components, Uronic acids showed the strongest affinities to …


The Effects Of Industrial Biomass Gasification Ash As A Soil Amendment On The Earthworm Eisenia Fetida, Michael J. Blackowicz Jan 2015

The Effects Of Industrial Biomass Gasification Ash As A Soil Amendment On The Earthworm Eisenia Fetida, Michael J. Blackowicz

Masters Theses

Soil application of solid residues from thermal conversion of biomass (i.e. combustion and pyrolysis) has become a topic of interest in recent years. However, there exists a gap in the literature with regard to soil application of gasification residues and their effects on soil health and soil macroorganisms. This study investigates the effects of three different ashes (hardwood oak/hickory, hardwood willow, corn stover), collected from industrial biomass gasification reactors (University of Minnesota Morris, Eastern Illinois University), as a soil amendment on the composting worm Eisenia fetida. Additionally, ash samples were analyzed for total polycyclic aromatic hydrocarbons (PAHs) and potentially toxic …


Effects Of Anthropogenic Particles On The Chemical And Geophysical Properties Of Urban Soils, Detroit, Michigan, Katharine Orlicki Jan 2015

Effects Of Anthropogenic Particles On The Chemical And Geophysical Properties Of Urban Soils, Detroit, Michigan, Katharine Orlicki

Wayne State University Theses

There is a great need in many cities for a better quality of urban soil maps. This is due to the increasing interest in repurposing vacant land for urban redevelopment, agriculture, and green infrastructure. Mapping vacant urban land in Detroit can be very difficult because anthropogenic soils were often highly variable and frequently contained demolition debris (such as brick), this makes it difficult to use a hand auger. This study was undertaken in Detroit, MI to create a more efficient way to map urban soils based on their geophysical and chemical properties. This will make the mapping process faster, less …


Subsurface Geological Analyses Of The Berea Petroleum System In Eastern Kentucky, Julie Floyd Jan 2015

Subsurface Geological Analyses Of The Berea Petroleum System In Eastern Kentucky, Julie Floyd

Theses and Dissertations--Earth and Environmental Sciences

The Berea Sandstone is a Late Devonian, tight oil and gas reservoir that intertongues with the Bedford Shale in eastern Kentucky. In order to evaluate the Bedford-Berea interval in the subsurface, 555 well logs from the Kentucky Geological Survey’s oil and gas database were used to construct structure maps, isopach maps, and cross sections of the interval and its possible hydrocarbon source rocks. Gamma-ray logs were compared to known cores in order to separate Bedford from Berea lithologies. Maps and cross sections were compared to known basement structures to evaluate possible structural influences on the interval.

The Bedford-Berea interval is …


Keflavík On Hegranes: Cemetery Excavation—Interim Report2015, Guðný Zoega, Douglas J. Bolender, Brian N. Damiata, John M. Steinberg Jan 2015

Keflavík On Hegranes: Cemetery Excavation—Interim Report2015, Guðný Zoega, Douglas J. Bolender, Brian N. Damiata, John M. Steinberg

Andrew Fiske Memorial Center for Archaeological Research Publications

The summer of 2015 was the first of three planned years of excavations at the early Christian cemetery at farm Keflavík on Hegranes in the region of Skagafjörður, North Iceland. The excavation is the third phase of Skagfirska kirkjurannsóknin (Skagafjörður Church Project) and is a collective effort of the Skagafjörður Heritage Museum and the Fiske Center of the University of MassachusettsBoston. The collective project goes by the name Skagafjörður Church and Settlement Survey (SCASS). The excavation season started on the 6thof July and finished on the 14thof August. The first two weeks were spent cleaning the surface and removing a …


Guidance Counselor Survey, Chery Justice, Kathleen Sherman-Morris, Kimberly Hall Jan 2015

Guidance Counselor Survey, Chery Justice, Kathleen Sherman-Morris, Kimberly Hall

CAS Publications

This is a survey created to study guidance/career counselor opinions about the geosciences and other STEM fields, and the career counseling activities they use.


Lower Devonian Trace Fossils And Their Paleoenvironmental Significance From The Western Yangtze Plate, South China, Li-Jun Zhang, Zhao Zhao Jan 2015

Lower Devonian Trace Fossils And Their Paleoenvironmental Significance From The Western Yangtze Plate, South China, Li-Jun Zhang, Zhao Zhao

Turkish Journal of Earth Sciences

Abundant and diverse trace fossils occur in the littoral-neritic sediments recording an Early Devonian transgression in South China. The well-exposed Ganxi section is located in the Longmen Mountain 100 km northwest of Chendu, Sichuan. The Lower Devonian strata are dominated by sandstones, siltstones, muddy shales, limestones, bioclastic limestones, and muddy limestones. About thirteen ichnogenera were systematically described, including Arenicolites, ?Balanoglossites, Chondrites, Cylindrichnus, Diplocraterion, Planolites, Palaeophycus, Phycodes, Rhizocorallium, Rusophycus, Skolithos, Thalassinoides, and Zoophycos. Six trace fossil associations under different sedimentary environments have been recognized as follows: the Skolithos and Diplocraterion-Skolithos associations mainly consist of domichnia derived from a high-energy zone of …


Monitoring Soil Response To Decreasing Acidic Deposition In A Western Adirondack Tributary Over A 16 Year Period, Michael Robert Antidormi Jan 2015

Monitoring Soil Response To Decreasing Acidic Deposition In A Western Adirondack Tributary Over A 16 Year Period, Michael Robert Antidormi

Legacy Theses & Dissertations (2009 - 2024)

Abstract


Comparison Of Glucose, Fructose And Sucrose Amperometric And Thermal Sensors For Detection Of Carbohydrates In Living Plant Tissue, Scott Mcadoo Jan 2015

Comparison Of Glucose, Fructose And Sucrose Amperometric And Thermal Sensors For Detection Of Carbohydrates In Living Plant Tissue, Scott Mcadoo

Legacy Theses & Dissertations (2009 - 2024)

Ecologists currently cannot test concentrations of carbohydrates in sap in vivo. Testing carbohydrates with current technology would require destructive tissue sampling. The tissue sampling involves large amounts of time and money to collect and test. Aphids are an insect that can bypass a tree’s passive immune system and feed off a phloem region for weeks. A series of enzymatic biosensors could be used to detect the concentration changes of specific carbohydrates. A calcium chelant can be added to defeat a tree’s immune system like an aphid. The detection of three carbohydrates, fructose, glucose and sucrose are involved in this study. …


Wetchimp-Wsl: Intercomparison Of Wetland Methane Emissions Models Over West Siberia, T. J. Bohn, J. R. Melton, A. Ito, T. Kleinen, R. Spahni, B. D. Stocker, B. Zhang, X. Zhu, R. Schroeder, M. V. Glagolev, S. Maksyutov, V. Brovkin, G. Chen, S. N. Denisov, A. V. Eliseev, A. Gallego-Sala, K. C. Mcdonald, M. A. Rawlins, W. J. Riley, Z. M. Subin, H. Tian, Q. Zhuang, J. O. Kaplan Jan 2015

Wetchimp-Wsl: Intercomparison Of Wetland Methane Emissions Models Over West Siberia, T. J. Bohn, J. R. Melton, A. Ito, T. Kleinen, R. Spahni, B. D. Stocker, B. Zhang, X. Zhu, R. Schroeder, M. V. Glagolev, S. Maksyutov, V. Brovkin, G. Chen, S. N. Denisov, A. V. Eliseev, A. Gallego-Sala, K. C. Mcdonald, M. A. Rawlins, W. J. Riley, Z. M. Subin, H. Tian, Q. Zhuang, J. O. Kaplan

Publications and Research

Wetlands are the world’s largest natural source of methane, a powerful greenhouse gas. The strong sensitivity of methane emissions to environmental factors such as soil temperature and moisture has led to concerns about potential positive feedbacks to climate change. This risk is particularly relevant at high latitudes, which have experienced pronounced warming and where thawing permafrost could potentially liberate large amounts of labile carbon over the next 100 years. However, global models disagree as to the magnitude and spatial distribution of emissions, due to uncertainties in wetland area and emissions per unit area and a scarcity of in situ observations. …


Ecohydraulic Investigation Of Diatoms In A Bedrock-Controlled Stream, Alex M. Rittle Jan 2015

Ecohydraulic Investigation Of Diatoms In A Bedrock-Controlled Stream, Alex M. Rittle

Theses and Dissertations--Geography

Recent studies within the past decade or so have shown the importance of algae in geomorphic and hydrologic processes of lotic systems. However, the ecohydraulic role of algae in bedrock systems has largely been ignored. In addition, the utility of algae as indicators of channel dynamics have often been assumed by geomorphologists, but relatively few studies have examined this relationship. The purpose of this study was to determine whether algae, specifically diatoms, are useful indicators of channel geomorphological dynamics, and to examine if distinct habitats or biotopes typical in fluviokarst and bedrock systems provide unique habitat space for diatoms, and …


Origin, Evolution, And Tectonic Setting Of The Eastern Part Of The Mexican Volcanic Belt And Comparison With The Central American Volcanic Arc From Conventional Multielement Normalized And New Multidimensional Discrimination Diagrams And Discordancy And Significance Tests, Surendra P. Verma Jan 2015

Origin, Evolution, And Tectonic Setting Of The Eastern Part Of The Mexican Volcanic Belt And Comparison With The Central American Volcanic Arc From Conventional Multielement Normalized And New Multidimensional Discrimination Diagrams And Discordancy And Significance Tests, Surendra P. Verma

Turkish Journal of Earth Sciences

If both the Mexican Volcanic Belt (MVB) and the Central American Volcanic Arc (CAVA) have been related to the subduction of the Cocos plate beneath the North American and Caribbean plates, respectively, their magmas, and especially the less evolved basic varieties, should show considerable similarities. The conventional multielement normalized diagrams indicate more complex petrogenetic processes for the MVB than the CAVA. Forty-five statistically coherent tectonomagmatic discrimination diagrams were used to infer the tectonic setting of the controversial geological subprovince of the eastern part of the MVB (E-MVB). Basic rocks from the E-MVB indicated a continental rift setting, whereas the intermediate …


Magnetomineralogical Changes Along The Kohistan-Karakoram Collision Zone Innorth Pakistan: Implications For Variable Thermochemical Activities, Haider Zaman, Abdullah O. Bamousa Jan 2015

Magnetomineralogical Changes Along The Kohistan-Karakoram Collision Zone Innorth Pakistan: Implications For Variable Thermochemical Activities, Haider Zaman, Abdullah O. Bamousa

Turkish Journal of Earth Sciences

To identify remanence-carrying magnetic minerals and document their thermochemical behavior, detailed rock magnetic investigations were conducted on Cretaceous-Tertiary rocks collected from northwestern and northeastern Kohistan, northern Pakistan. Rock magnetic results from each area are clearly differentiated on the basis of site location. Detrital hematite is identified as a main magnetic carrier in red beds of northwestern Kohistan located at some distance from the Northern Suture Zone with subsidiary pigmentary hematite and altered magnetite. In contrast, the magnetic mineralogy of purple-colored rocks adjacent to the Northern Suture Zone is shared by unstable secondary pyrrhotite, magnetite, and hematite. The magnetic mineralogy of …


Clay Mineralogy, Chemistry, And Diagenesis Of Late Devonian K-Bentonite Occurrences In Northwestern Turkey, Asuman Günal Türkmenoğlu, Ömer Bozkaya, Mehmet Cemal Göncüoğlu, Özge Ünlüce, İsmai̇l Ömer Yilmaz, Cengi̇z Okuyucu Jan 2015

Clay Mineralogy, Chemistry, And Diagenesis Of Late Devonian K-Bentonite Occurrences In Northwestern Turkey, Asuman Günal Türkmenoğlu, Ömer Bozkaya, Mehmet Cemal Göncüoğlu, Özge Ünlüce, İsmai̇l Ömer Yilmaz, Cengi̇z Okuyucu

Turkish Journal of Earth Sciences

Thin beds of tephra (K-bentonites) formed by the diagenesis of volcanic ash are exposed within the limestone-dolomitic limestone successions of the Yılanlı formation at Zonguldak and Bartın in northwestern Turkey. They were deposited on the Middle Devonian-Lower Carboniferous shallow carbonate platform of the Zonguldak terrane. In this study, K-bentonite samples collected from Gavurpınarı and Yılanlı Burnu limestone quarries are investigated in order to reveal their mineralogical and geochemical characteristics and diagenetic evolution. Illite is the major clay mineral in the studied K-bentonites. Additionally, kaolinite and mixed-layer illite-smectite are identified in some samples. The nonclay minerals calcite, dolomite, quartz, gypsum, feldspar, …


Nature And Physicochemical Conditions Of Crystallization In The South Dehgolan Intrusion, Nw Iran: Mineral-Chemical Evidence, Fatemeh Sarjoughian, Ali Kananian, David Richard Lentz, Jamshid Ahmadian Jan 2015

Nature And Physicochemical Conditions Of Crystallization In The South Dehgolan Intrusion, Nw Iran: Mineral-Chemical Evidence, Fatemeh Sarjoughian, Ali Kananian, David Richard Lentz, Jamshid Ahmadian

Turkish Journal of Earth Sciences

The South Dehgolan intrusion in the Sanandaj-Sirjan Zone ranges in composition from calc-alkalic monzogabbro to syenite to alkalic granite. This suite is composed mainly of variable proportions of quartz, K-feldspar, plagioclase, biotite, hornblende, and pyroxene. The plagioclase composition varies between albite to labradorite. The biotites are Mg- to Fe-rich in the monzogabbro to granite, respectively. The amphiboles are calcic and the composition varies from magnesiohornblende to actinolite. Clinopyroxene compositions fall in the diopside-augite field. The average calculated near-solidus crystallization temperatures are 774 °C, 655 °C, and 775 °C for the monzogabbro-monzodiorite, syenite, and granite, respectively. Calculated average pressures of emplacement …