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2009

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Articles 391 - 420 of 560

Full-Text Articles in Earth Sciences

Hydrodynamic Simulations Of Physical Aquatic Habitat Availability For Pallid Sturgeon In The Lower Missouri River, At Yankton, South Dakota, Kenslers Bend, Nebraska, Little Sioux, Iowa, And Miami, Missouri, 2006–07, Robert B. Jacobson, Harold E. Johnson Iii, Benjamin J. Dietsch Jan 2009

Hydrodynamic Simulations Of Physical Aquatic Habitat Availability For Pallid Sturgeon In The Lower Missouri River, At Yankton, South Dakota, Kenslers Bend, Nebraska, Little Sioux, Iowa, And Miami, Missouri, 2006–07, Robert B. Jacobson, Harold E. Johnson Iii, Benjamin J. Dietsch

United States Geological Survey: Publications

The objective of this study was to assess the sensitivity of habitat availability in the Lower Missouri River to discharge variation, with emphasis on habitats that might support spawning of the endangered pallid sturgeon. We constructed computational hydrodynamic models for four reaches that were selected because of evidence that sturgeon have spawned in them. The reaches are located at Miami, Missouri (river mile 259.6–263.5), Little Sioux, Iowa (river mile 669.6–673.5), Kenslers Bend, Nebraska (river mile 743.9–748.1), and Yankton, South Dakota reach (river mile 804.8–808.4). The models were calibrated for a range of measured flow conditions, and run for a range …


Toxicity Of Polybrominated Diphenyl Ethers (De-71) In Chicken (Gallus Gallus), Mallard (Anas Platyrhynchos), And American Kestrel (Falco Sparverius) Embryos And Hatchlings, Moira A. Mckernan, Barnett A. Rattner, Robert C. Hales, Mary Ann Ottinger Jan 2009

Toxicity Of Polybrominated Diphenyl Ethers (De-71) In Chicken (Gallus Gallus), Mallard (Anas Platyrhynchos), And American Kestrel (Falco Sparverius) Embryos And Hatchlings, Moira A. Mckernan, Barnett A. Rattner, Robert C. Hales, Mary Ann Ottinger

United States Geological Survey: Staff Publications

Embryonic survival, pipping and hatching success, and sublethal biochemical, endocrine, and histological endpoints were examined in hatchling chickens (Gallus gallus), mallards (Anas platyrhynchos), and American kestrels (Falco sparverius) following air cell administration of a pentabrominated diphenyl ether (penta-BDE; DE-71) mixture (0.01–20 µg/g egg) or polychlorinated biphenyl (PCB) congener 126 (3,3’,4,4’,5-pentachlorobiphenyl; 0.002 µg/g egg). The penta-BDE decreased pipping and hatching success at concentrations of 10 and 20 µg/g egg in kestrels but had no effect on survival endpoints in chickens or mallards. Sublethal effects in hatchling chickens included ethoxyresorufin-O-dealkylase (EROD) induction and histological …


Tree Die-Off In Response To Global Change-Type Drought: Mortality Insights From A Decade Of Plant Water Potential Measurements, David D. Breshears, Orrin B. Meyers, Clifton W. Meyer, Fairley J. Barnes, Chris B. Zou, Craig D. Allen, Nathan G. Mcdowell, William Pockman Jan 2009

Tree Die-Off In Response To Global Change-Type Drought: Mortality Insights From A Decade Of Plant Water Potential Measurements, David D. Breshears, Orrin B. Meyers, Clifton W. Meyer, Fairley J. Barnes, Chris B. Zou, Craig D. Allen, Nathan G. Mcdowell, William Pockman

United States Geological Survey: Staff Publications

Global climate change is projected to produce warmer, longer, and more frequent droughts, referred to here as “global change-type droughts”, which have the potential to trigger widespread tree die-off. However, drought-induced tree mortality cannot be predicted with confidence, because long-term field observations of plant water stress prior to, and culminating in, mortality are rare, precluding the development and testing of mechanisms. Here, we document plant water stress in two widely distributed, co-occurring species, piñon pine (Pinus edulis) and juniper (Juniperus monosperma), over more than a decade, leading up to regional-scale die-off of piñon pine trees in …


Salt River Basin, Daniel I. Carey Jan 2009

Salt River Basin, Daniel I. Carey

Map and Chart--KGS

The Salt River Basin and adjacent Ohio River drainages include over 4,150 square miles in all or parts of 19 counties. The basin contains more than 9,600 miles of streams.

Over 660 miles of streams assessed in the basin by the Kentucky Division of Water do not support designated uses for warm-water aquatic habitat, fish consumption, or primary contact recreation (swimming). Not all streams have been assessed. The percentage of assessed streams not supporting uses was: warm-water aquatic habitat (38 percent); fish consumption (36 percent); primary contact recreation (86 percent). Over 100 miles of streams have been declared special use …


Big Sandy/Little Sandy And Tygarts Creek Basins, Daniel I. Carey Jan 2009

Big Sandy/Little Sandy And Tygarts Creek Basins, Daniel I. Carey

Map and Chart--KGS

Nearly 7,600 miles of streams flow through the basin's 3,440 square miles in 14 counties to the Tug Fork, Big Sandy River, and Ohio River. The Tygarts Creek–Little Sandy River Basin includes 1,160 square miles. The Big Sandy River Basin has 2,285 square miles in Kentucky and 1,950 square miles in West Virginia and Virginia. There are nearly 17,000 acres of wetlands, including water bodies.

Residents draw about 27 million gallons of water per day (mgd) from streams and reservoirs in the basin. About three in five residents are on public water; other households rely primarily on domestic wells. Only …


Kentucky River Basin, Daniel I. Carey Jan 2009

Kentucky River Basin, Daniel I. Carey

Map and Chart--KGS

The Kentucky River Basin's nearly 7,000 square miles in 42 counties contain 16,000 miles of streams. From a hill in Letcher County 3,250 feet above sea level, and the Kentucky River runs down the Eastern Kentucky Coal Field, Knobs, and Bluegrass Regions to the Ohio River at 420 feet above sea level.

Along the way the river washes rocks laid down as sediments over a period of 150 million years—past the 300-million-year-old sandstone, siltstone, shale, and Camp Nelson limestones at the base of the Kentucky River Palisades in central Kentucky.

Residents draw about 100 million gallons of water per day …


Unusual Anatomy Of The Ectoparasitic Muricid Vitularia Salebrosa (King And Broderip, 1832) (Neogastropoda: Muricidae) From The Pacific Coast Of Panama, Luiz R. L. Simone, Gregory S. Herbert, Didier Merle Jan 2009

Unusual Anatomy Of The Ectoparasitic Muricid Vitularia Salebrosa (King And Broderip, 1832) (Neogastropoda: Muricidae) From The Pacific Coast Of Panama, Luiz R. L. Simone, Gregory S. Herbert, Didier Merle

School of Geosciences Faculty and Staff Publications

The morphology and anatomy of Vitularia salebrosa, a muricid ectoparasitic on other mollusks, are investigated based on study of specimens from western Panama. Distinctive characters of this species include the small size of the buccal mass and radular apparatus, simplification of the odontophore muscles and diminished lateral teeth of the radula; an elongated, narrow proboscis; narrow digestive tract and a differentiable glandular region at the beginning of the posterior esophagus. These traits are consistent with adaptive specialization for an ectoparasitic life history


Extremely Slow Feeding In A Tropical Drilling Ectoparasite, Vitularia Salebrosa (King And Broderip, 1832) (Gastropoda: Muricidae), On Molluscan Hosts From Pacific Panama, Gregory S. Herbert, Gregory P. Dietl, Helena Fortunato, Luiz R. L. Simone, Jennifer Leigh Sliko Jan 2009

Extremely Slow Feeding In A Tropical Drilling Ectoparasite, Vitularia Salebrosa (King And Broderip, 1832) (Gastropoda: Muricidae), On Molluscan Hosts From Pacific Panama, Gregory S. Herbert, Gregory P. Dietl, Helena Fortunato, Luiz R. L. Simone, Jennifer Leigh Sliko

School of Geosciences Faculty and Staff Publications

This study documents one of the slowest feeding behaviors ever recorded for a muricid gastropod in one of the most biotically rigorous regions on the planet. In Pacific Panama, Vitularia salebrosa attacks mollusks by drilling through their shells. The duration of attacks estimated by isotope sclerochronology of oyster shells collected during attacks in progress ranges from 90 to 230 days, while experimental observation of interactions documented one attack greater than 103 days. The prolonged nature of attacks suggests that V. salebrosa is best characterized as an ectoparasite than as a predator, which is the ancestral condition in the Muricidae. An …


Eastern Nebraska Water Resources Assessment (Enwra): Introduction To A Hydrogeological Study, Dana Divine, R. Matthew Joeckel, Jesse T. Korus, P.R. Hanson, Sue Olafsen Lackey Jan 2009

Eastern Nebraska Water Resources Assessment (Enwra): Introduction To A Hydrogeological Study, Dana Divine, R. Matthew Joeckel, Jesse T. Korus, P.R. Hanson, Sue Olafsen Lackey

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Variations In Sea Surface Roughness Induced By The 2004 Sumatra-Andaman Tsunami, O. A. Godin, V. G. Irisov, R. R. Leben, B. D. Hamlington, G. A. Wick Jan 2009

Variations In Sea Surface Roughness Induced By The 2004 Sumatra-Andaman Tsunami, O. A. Godin, V. G. Irisov, R. R. Leben, B. D. Hamlington, G. A. Wick

CCPO Publications

Observations of tsunamis away from shore are critically important for improving early warning systems and understanding of tsunami generation and propagation. Tsunamis are difficult to detect and measure in the open ocean because the wave amplitude there is much smaller than it is close to shore. Currently, tsunami observations in deep water rely on measurements of variations in the sea surface height or bottom pressure. Here we demonstrate that there exists a different observable, specifically, ocean surface roughness, which can be used to reveal tsunamis away from shore. The first detailed measurements of the tsunami effect on sea surface height …


Southern Ocean Globec Research And The Future, Eileen Hofmann Jan 2009

Southern Ocean Globec Research And The Future, Eileen Hofmann

CCPO Publications

(First paragraph) The International Global Ocean Ecosystems Dynamics (GLOBEC) Programme will end in early 2010, after almost 20 years. GLOBEC science has provided fundamental changes in our understanding of the scales of interactions in marine ecosystems, alternative views of marine food webs, and the influence of humans in marine ecosystem processes. Since Southern Ocean GLOBEC (SO GLOBEC) was one of the regional research programmes it is appropriate to reflect on i) its specific contributions, ii) how these might guide future Southern Ocean research, and iii) the key gaps for our future understanding of Southern Ocean ecosystems and the impact that …


Integration Of An Extended Octagonal Ring Transducer And Soil Coulterometer For Identifying Soil Compaction, Santosh K. Pitla, Larry G. Wells, Scott A. Shearer Jan 2009

Integration Of An Extended Octagonal Ring Transducer And Soil Coulterometer For Identifying Soil Compaction, Santosh K. Pitla, Larry G. Wells, Scott A. Shearer

Biosystems and Agricultural Engineering Faculty Publications

The soil coulterometer is an "on-the-go" electro-mechanical system which collects impedance force data at multiple depths using an oscillating coulter. During the initial testing (summer 2006), only vertical soil impedance force data was collected using a pressure sensor. To improve the performance of the coulterometer, an extended octagonal ring transducer was integrated into the system to collect both the horizontal and vertical impedance forces given by the soil. In the summer of 2007, data was collected using the revised sensor from a typical central Kentucky field setting in a 0.8-ha (2-acre) plot. Four passes were made with the coulterometer. Seventy …


Photochemical Degradation Of Dissolved Organic Matter And Dissolved Lignin Phenols From The Congo River, Robert G. M. Spencer, Aron Stubbins, Peter J. Hernes, Kenneth Mopper, Anthony K. Aufdenkampe, Rachael Y. Dyda, Vincent L. Mwamba, Arthur M. Mangangu, Jose N. Wabakanghanzi, Johan Six Jan 2009

Photochemical Degradation Of Dissolved Organic Matter And Dissolved Lignin Phenols From The Congo River, Robert G. M. Spencer, Aron Stubbins, Peter J. Hernes, Kenneth Mopper, Anthony K. Aufdenkampe, Rachael Y. Dyda, Vincent L. Mwamba, Arthur M. Mangangu, Jose N. Wabakanghanzi, Johan Six

Chemistry & Biochemistry Faculty Publications

Photochemical degradation of Congo River dissolved organic matter (DOM) was investigated to examine the fate of terrigenous DOM derived from tropical ecosystems. Tropical riverine DOM receives greater exposure to solar radiation, particularly in large river plumes discharging directly into the open ocean. Initial Congo River DOM exhibited dissolved organic carbon (DOC) concentration and compositional characteristics typical of organic rich blackwater systems. During a 57 day irradiation experiment, Congo River DOM was shown to be highly photoreactive with a decrease in DOC, chromophoric DOM (CDOM), lignin phenol concentrations (Σ8) and carbon-normalized yields (Λ8), equivalent to losses of ~45, 85–95, >95 and …


Evaluating Lake Response To Environmental And Climatic Change Using Lake Core Records And Modeling, Brandi Bracht-Flyr Jan 2009

Evaluating Lake Response To Environmental And Climatic Change Using Lake Core Records And Modeling, Brandi Bracht-Flyr

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

This dissertation evaluates how lakes respond to changes in their environmental and climatic settings. This dissertation consists of two lake modeling projects and the environmental and paleoclimatic reconstructions of four lakes in southwestern Montana. Lakes and their associated biological communities respond to environmental and climatic change on rapid timescales. Lake modeling and lake core stratigraphies are complementary tools for exploration of how lakes and their biota respond to environmental or climatic perturbations. In one modeling approach for exploring these issues, a simple hydro-climatological lake model was developed that classifies lake sensitivity to climatic perturbations based upon lake area, catchment area, …


Digital Reconstruction Of A Ceratopsid Pes, Ken Conrad Noriega Jan 2009

Digital Reconstruction Of A Ceratopsid Pes, Ken Conrad Noriega

Theses Digitization Project

A complete and fully articulated right pes of a centrosaurine ceratopsid from the Dinossaur Park Formation of Alberta, Canada provides important information regarding the structure and function of the pelvic limb in this group. A reconstructed centrosaurine foot with all data coming directly from actual specimens could be accurately modeled in three-dimensional morphospace and provide the basis of a digital atlas of the elements.


What Is Diplograptus?, Charles Mitchell, Jörg Maletz, Daniel Goldman Jan 2009

What Is Diplograptus?, Charles Mitchell, Jörg Maletz, Daniel Goldman

Department of Earth, Environment and Sustainability Faculty Publications

Diplograptus pristis (Hisinger, 1837) is the type species of the genus Diplograptus and name bearer for suborder Diplograptina. This species is primarily known from the Dalarne region of Sweden, where it occurs in the P. linearis Zone. D. pristis exhibits a suite of features (particularly the shape of the proximal end, the configuration of proximal spines, and the gradient in thecal form) that is uniquely shared with a number of other late Katian and earliest Hirnantian species including Glyptograptus nicholsoni Toghill, 1970; Glyptograptus posterus Koren’ & Tzai (in Apollonov et al. 1980); Orthograptus maximus Mu, 1945; and Orthograptus truncatus rarithecatus …


X-Ray Diffraction Study Of Dysprosium Single Crystal Samples In A Diamond Anvil Cell (Dac), Ognjen Grubor-Urosevic Jan 2009

X-Ray Diffraction Study Of Dysprosium Single Crystal Samples In A Diamond Anvil Cell (Dac), Ognjen Grubor-Urosevic

UNLV Theses, Dissertations, Professional Papers, and Capstones

X-ray diffraction is the basis of crystallography, the study of the structure of crystals. It uses X-rays of a wavelength on the order of the size of atoms, so it can resolve the positions of individual atoms in a crystal. Illuminating the crystal with a well-collimated X-ray beam produces X-rays diffracted in a certain direction for a specific crystal orientation. By analyzing the relative phase of the incoming and outgoing scattered X-rays, the unique arrangements of atoms can be determined and the structure of the crystal can be solved.

There is a long standing controversy regarding the crystal structures and …


Alteration Mineralogy And Geochemistry Of The Hydrothermally Altered Rocks Of The Kutlular (Sürmene) Massive Sulfide Deposit, Ne Turkey, Emel Abdi̇oğlu, Mehmet Arslan Jan 2009

Alteration Mineralogy And Geochemistry Of The Hydrothermally Altered Rocks Of The Kutlular (Sürmene) Massive Sulfide Deposit, Ne Turkey, Emel Abdi̇oğlu, Mehmet Arslan

Turkish Journal of Earth Sciences

Volcanogenic massive sulfide deposits accompanying the Upper Cretaceous felsic rocks in the intra-arc rift zone of the Pontide palaeo-arc are common in the NE Turkey. One of them, the Kutlular (Sürmene, Trabzon) deposit, is an abandoned mine within the Upper Cretaceous mafic, felsic volcanics and subvolcanic rocks. Detailed mineralogical and geochemical studies indicate the presence of hydrothermal alteration zones around the Kutlular deposit; these alteration zones are represented by silicification-pyrite-illite zone, illite-silicification zone, illite/smectite-silicification zone, smectite zone accompanying kaolinite and halloysite in the dacitic pyroclastics, and additionally chlorite zone in the mafic volcanics. Lithogeochemical data indicate that the footwall dacitic …


Lead And Sulfur Isotope Studies Of The Koru (Çanakkale, Turkey) Lead-Zinc Deposits, Gülcan Bozkaya, Ahmet Gökçe Jan 2009

Lead And Sulfur Isotope Studies Of The Koru (Çanakkale, Turkey) Lead-Zinc Deposits, Gülcan Bozkaya, Ahmet Gökçe

Turkish Journal of Earth Sciences

Koru (Çanakkale) barite-bearing lead-zinc deposits are typical examples of the lead-zinc deposits occurring in the Tertiary volcanic rocks which crop out in the Biga Peninsula. Volcanic rocks around the investigated deposits are distinguished as Eocene Akçaalan andesite, Oligocene Adadağı pyroclastics, Miocene Dededağ dacite and Plio-Quaternary Karaömerler basalt. The investigated deposits are hosted by Adadağı pyroclastics and show two different mineralization styles such as stockwork ore veinlets in the upper parts and ore veins along the fault zones in WNW-ESE direction, in the lower parts. Sphalerite, galena, pyrite, chalcopyrite, quartz, barite and calcite are the main minerals and they are accompanied …


^{207}Pb-^{206}Pb, ^{40}Ar-^{39}Ar And Apatite Fission-Track Geothermochronology Revealing The Emplacement, Cooling And Exhumation History Of The Karaçayır Syenite (N Sivas), East-Central Anatolia, Turkey, Durmuş Boztuğ, Esra Türksever, Matt Heizler, Raymond J. Jonckheer, Marion Tichomirowa Jan 2009

^{207}Pb-^{206}Pb, ^{40}Ar-^{39}Ar And Apatite Fission-Track Geothermochronology Revealing The Emplacement, Cooling And Exhumation History Of The Karaçayır Syenite (N Sivas), East-Central Anatolia, Turkey, Durmuş Boztuğ, Esra Türksever, Matt Heizler, Raymond J. Jonckheer, Marion Tichomirowa

Turkish Journal of Earth Sciences

The Karaçayır syenite, intruding the Palaeozoic crustal metamorphics and unconformably overlain by Upper Paleocene to Eocene Tokuş formation in the north of Sivas (east-central Anatolia), has been studied with respect to ^{207}Pb-^{206}Pb single zircon evaporation, biotite ^{40}Ar-^{39}Ar, and apatite fission-track geothermochronology. ^{207}Pb-^{206}Pb single zircon evaporation dating yields an age of 99.0±11.0 Ma (Cenomanian-Turonian) which is considered to be the intrusion age. Biotite ^{40}Ar-^{39}Ar age determination gives a cooling age of ca. 65 Ma. Apatite fission-track dating, combined with T-t modeling based on track-length distribution data, determines a fast tectonic exhumation with an uplift rate of > 1 mm/a which occurred 58-61 …


Mineral Chemistry And Petrochemistry Of Post-Collisional Tertiary Mafic To Felsic Cogenetic Volcanics In The Ulubey (Ordu) Area, Eastern Pontides, Ne Turkey, İrfan Temi̇zel, Mehmet Arslan Jan 2009

Mineral Chemistry And Petrochemistry Of Post-Collisional Tertiary Mafic To Felsic Cogenetic Volcanics In The Ulubey (Ordu) Area, Eastern Pontides, Ne Turkey, İrfan Temi̇zel, Mehmet Arslan

Turkish Journal of Earth Sciences

Post-collisional Tertiary volcanic rocks in the Ulubey (Ordu) area at the western edge of the eastern Pontides palaeo-arc are divided into four suites. The Yenisayaca basalt (TB) contains plagioclase (An_{61-83}), clinopyroxene (Wo_{42-44}En_{39-41}Fs_{15-18}) and olivine phenocrysts and titanomagnetite microphenocrysts, whereas the Çatal Tepe and Elekçioğlu Tepe suite (ÇES), Işık Tepe suite (ITS) and andesite/ trachyandesite suite (ATS) rocks include plagioclase (An_{23-78}), clinopyroxene (Wo_{27-48}En_{37-55}Fs_{11-26}), hornblende (Mg#= 0.63-0.76), biotite (Mg#= 0.63-0.82), sanidine phenocrysts and titanomagnetite and apatite microphenocrysts. Petrochemically, the volcanic rocks show tholeiitic-alkaline to the calc-alkaline affinities, and have medium to high-K contents. Most samples have low Mg#, Cr, and Ni, which …


Geochemical Characteristics Of Mafic And Intermediate Volcanic Rocks From The Hasandağ And Erciyes Volcanoes (Central Anatolia, Turkey), Aykut Güçteki̇n, Nezi̇hi̇ Köprübaşi Jan 2009

Geochemical Characteristics Of Mafic And Intermediate Volcanic Rocks From The Hasandağ And Erciyes Volcanoes (Central Anatolia, Turkey), Aykut Güçteki̇n, Nezi̇hi̇ Köprübaşi

Turkish Journal of Earth Sciences

Hasandağ and Erciyes stratovolcanoes, which are the two important stratovolcanoes in Central Anatolia, erupted volcanic products with both calc-alkaline and alkaline compositions, although the calc-alkaline activity is more widespread. There are three stages of geochemical evolution in the history of the Hasandağ stratovolcanic complex: (1) Keçikalesi tholeiitic volcanism, (2) Hasandağ calc-alkaline volcanism, and (3) Hasandağ alkaline volcanism. The geochemical evolution of Erciyes volcanic complex also exhibits three distinct evolutionary stages: (1) Koçdağ alkaline volcanism, (2) Koçdağ calc-alkaline volcanism and (3) Erciyes calc-alkaline volcanism. The volcanic rocks from both suites show enrichments in LREE relative to HREE. The rocks as a …


Compositional Variations, Zoning Types And Petrogenetic Implications Of Low-Pressure Clinopyroxenes In The Neogene Alkaline Volcanic Rocks Of Northeastern Turkey, Faruk Aydi̇n, Orhan Karsli, M. Burhan Sadiklar Jan 2009

Compositional Variations, Zoning Types And Petrogenetic Implications Of Low-Pressure Clinopyroxenes In The Neogene Alkaline Volcanic Rocks Of Northeastern Turkey, Faruk Aydi̇n, Orhan Karsli, M. Burhan Sadiklar

Turkish Journal of Earth Sciences

Clinopyroxene phenocrysts and microphenocrysts in different series of the Neogene alkaline volcanic rocks from the eastern Pontides (NE Turkey) record various stages in the crystallization conditions and evolution history of the alkaline melt as well as its origin. Crystal chemical studies reveal that the clinopyroxenes in each rock series show strong textural and compositional similarities, which all reflect a common petrogenetic affinity. They have relatively high Mg-numbers (0.68-0.95), variable Al_2O_3 (1.3-9.6 wt%), low TiO_2 (


Petrogenesis Of The Refahiye Ophiolite And Its Tectonic Significance For Neotethyan Ophiolites Along The İzmir-Ankara-Erzincan Suture Zone, Ender Sarifakioğlu, Hayretti̇n Özen, John A. Winchester Jan 2009

Petrogenesis Of The Refahiye Ophiolite And Its Tectonic Significance For Neotethyan Ophiolites Along The İzmir-Ankara-Erzincan Suture Zone, Ender Sarifakioğlu, Hayretti̇n Özen, John A. Winchester

Turkish Journal of Earth Sciences

The Refahiye ophiolite, situated near Erzincan in the eastern part of the İzmir-Ankara-Erzincan Suture Zone (İAESZ), is one of the best exposures of oceanic lithosphere in the northern branch of the Neotethyan Ocean. The ophiolite, mainly thrust southwards, transported on an ophiolitic mélange, over the Early Triassic-Campanian Munzur Limestone of the Anatolide-Tauride Platform, was also emplaced by north-directed backthrusting onto the Pontides in the Late Cretaceous. It displays an almost complete ophiolite series unconformably overlain by Tertiary volcano-sedimentary units. The mantle peridotites are dominated by harzburgites, with dunite bands and lenses locally cut by isolated diabase dykes, whereas the mafic-ultramafic …


The Relationship Between The Tectonic Setting Of The Lake İznik Basin And The Middle Strand Of The North Anatolian Fault, Kurultay Öztürk, Cenk Yaltirak, Bedri̇ Alpar Jan 2009

The Relationship Between The Tectonic Setting Of The Lake İznik Basin And The Middle Strand Of The North Anatolian Fault, Kurultay Öztürk, Cenk Yaltirak, Bedri̇ Alpar

Turkish Journal of Earth Sciences

The İznik Basin is an active depression created by a series of faults developed in relation to the Middle Strand of the North Anatolian Fault (NAFMS). The most important of these faults is the oblique Sölöz fault, which runs parallel to the NAFMS. It is interpreted as a releasing bend, and plays a crucial role in the evolution of the 75-m-deep ellipsoid-shaped depression in the southern part of the lake. The faults that limit the coastal alluvial plain on land, some of which developed during the early evolution of the NAFMS, are equally important in the development of the İznik …


Two-And-Three-Dimensional Crustal Thickness Of The Eastern Pontides (Ne Turkey), Nafiz Maden, Kenan Geli̇şli̇, Yener Eyüboğlu, Osman Bektaş Jan 2009

Two-And-Three-Dimensional Crustal Thickness Of The Eastern Pontides (Ne Turkey), Nafiz Maden, Kenan Geli̇şli̇, Yener Eyüboğlu, Osman Bektaş

Turkish Journal of Earth Sciences

The Eastern Pontide orogenic belt is divided into three subzones (northern, southern and axial zones) based on present lithologies and facies associations. NE-SW-, NW-SE- and E-W-trending fault systems, which play an important role in palaeotectonics and neotectonics of the Eastern Pontides, separate these zones. Three different methods were used to estimate the Moho depth from observed gravity value, namely (i) empirical relationship between Moho depth and Bouguer anomaly; (ii) spectral analysis of the radial wave number and; (iii) by the gravity inversion method. Power spectrum, a statistical approach, is a widely used technique to determine the depth of geological sources …


Anomalous Strong Reflections On High Resolution Seismic Data From The Turkish Shelf Of The Eastern Black Sea: Possible Indicators Of Shallow Hydrogen Sulphide-Rich Gas Hydrate Layers, Derman Dondurur, Günay Çi̇fçi̇ Jan 2009

Anomalous Strong Reflections On High Resolution Seismic Data From The Turkish Shelf Of The Eastern Black Sea: Possible Indicators Of Shallow Hydrogen Sulphide-Rich Gas Hydrate Layers, Derman Dondurur, Günay Çi̇fçi̇

Turkish Journal of Earth Sciences

Some strong reflections about 3 to 5 m thick were observed at depths of 25-60 metres below the sea floor using deep-towed, 5 kHz subbottom profiler data in the Turkish shelf and upper slope of the Eastern Black Sea at water depths of 250 to 700 m. Strong reflections of this kind are generally attributed to shallow and localized gas accumulations. We, however, observed that the reflection polarity of these strong reflections was positive, suggesting that they do not correspond to reflections from the upper boundary of a possible gas front. In this study, we evaluate these reflections to determine …


Benthonic Foraminiferal Biostratigraphy Of The Upper Cretaceous (Middle Cenomanian−Coniacian) Sequences Of The Bey Dağları Carbonate Platform, Western Taurides, Turkey, Bi̇lal Sari, Kemal Tasli, Saci̇t Özer Jan 2009

Benthonic Foraminiferal Biostratigraphy Of The Upper Cretaceous (Middle Cenomanian−Coniacian) Sequences Of The Bey Dağları Carbonate Platform, Western Taurides, Turkey, Bi̇lal Sari, Kemal Tasli, Saci̇t Özer

Turkish Journal of Earth Sciences

Identification of the benthonic foraminiferal assemblages from ten stratigraphic sections from the inner platform limestones of the Middle Cenomanian−Coniacian successions of the Bey Dağları carbonate platform (BDCP) allowed the recognition of one biozone and two subzones. The lower part of the platform limestones (Middle−Upper Cenomanian) is represented by relatively rich benthonic foraminiferal assemblages, while the upper part (Turonian−Coniacian) contains poor assemblages. The benthonic foraminiferal assemblages determined in the BDCP are dominated by long-ranging species. The shorter-ranging, stratigraphical index species have been selected to date the Upper Cretaceous platform limestones of the BDCP based on the distributions of the species in …


Ophiolite-Hosted Copper And Gold Deposits Of Southeastern Turkey: Formation And Relationship With Seafloor Hydrothermal Processes, Ömer Tezcan Akinci Jan 2009

Ophiolite-Hosted Copper And Gold Deposits Of Southeastern Turkey: Formation And Relationship With Seafloor Hydrothermal Processes, Ömer Tezcan Akinci

Turkish Journal of Earth Sciences

The paper documents evidence about the physical and chemical controls on the behaviour of Au and Cu sulphide deposits in fossil seafloor hydrothermal systems of SE Turkey. Observations from actively forming sulphides at mid-ocean ridges (MOR) and in back-arc environments are compared briefly with ancient analogues of gold and pyritic copper deposits such as Kisecik, Ergani and Siirt-Madenköy, formed at mid-oceanic ridges, or possibly at seamounts and back-arc settings. Many ophiolite-hosted Au- and Cu-deposits, of various sizes, are known to exist along the Bitlis-Zagros Suture Zone (BZS), the boundary between Anatolian and Arabian plates in SE Turkey. These deposits are …


Contemporaneous Late Cretaceous Calc-Alkaline And Alkaline Magmatism In Central Anatolia, Turkey: O Isotope Constraints On Petrogenesis, Nurdane İlbeyli̇, Julian A. Pearce, Ian G. Meighan, Anthony E. Fallick Jan 2009

Contemporaneous Late Cretaceous Calc-Alkaline And Alkaline Magmatism In Central Anatolia, Turkey: O Isotope Constraints On Petrogenesis, Nurdane İlbeyli̇, Julian A. Pearce, Ian G. Meighan, Anthony E. Fallick

Turkish Journal of Earth Sciences

A wide variety of rock types were produced by the latest Cretaceous magmatism in the Central Anatolian Crystalline Complex. These rocks can be divided into three distinct units: (i) calc-alkaline, (ii) subalkaline/transitional, and (iii) alkaline. The calc-alkaline rocks are mainly metaluminous (I-type) ranging from monzodiorite to granite. The subalkaline/transitional rocks are also metaluminous (I-type) ranging from monzonite to granite. The alkaline rocks are mainly peralkaline (A-type), ranging from feldspathoid-bearing monzosyenite to granite. Whole-rock oxygen isotope data from the complex have a considerable range of \delta18O values between 6.5 per thousand and 14.8 per thousand. Initial 87Sr/86Sr versus 143Nd/144Nd ratios, and …