Open Access. Powered by Scholars. Published by Universities.®

Geology Commons™

Open Access. Powered by Scholars. Published by Universities.®

2016

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 331 - 360 of 511

Full-Text Articles in Geology

Endangered Species Research In The Caribbean, James W. Wiley Jan 2016

Endangered Species Research In The Caribbean, James W. Wiley

United States Geological Survey: Staff Publications

Although indigenous Amerindian populations adversely affected the biota of their island environments, it was not until the arrival of Europeans that populations of many plant and animal species in the Caribbean Islands declined dramatically (Snyder and others, 1987). Island species are particularly vulnerable to changes in the environment, which, in the extreme, can lead to their extinction. The small populations of many species that occupy islands have limited gene pools and typically show extremes of specialization, characteristics that place those species at high risk for decline and extinction with rapid environmental change. The most important factor in the decline of …

Go to article

The Bird Banding Laboratory: Support For And Collaboration With Research At Patuxent, John Tautin Jan 2016

The Bird Banding Laboratory: Support For And Collaboration With Research At Patuxent, John Tautin

United States Geological Survey: Staff Publications

Located at Patuxent Research Refuge (PRR) and functionally part of the Patuxent Wildlife Research Center (Patuxent), Laurel, MD, the Bird Banding Laboratory (BBL) is the service and administrative center for bird banding in the United States. Over the years, the BBL has been associated with both the PRR and Patuxent, which collectively are commonly referred to by the public (and in this chapter) as “Patuxent.” The BBL issues permits and bands; supplies banding software, instructional materials, and technical advice; coordinates the use of auxiliary markers such as neck collars and radio transmitters; serves as the repository for banding records and …

Go to article

Endangered Species Research In Hawaii: The Early Years (1965–87), Michael J. Scott, Cameron B. Kepler Jan 2016

Endangered Species Research In Hawaii: The Early Years (1965–87), Michael J. Scott, Cameron B. Kepler

United States Geological Survey: Staff Publications

Hawaii is an ecologically isolated archipelago 2,500 miles from the nearest continent. Its isolation resulted in a taxonomically unbalanced flora and fauna with remarkable examples of adaptive radiation among those groups of organisms that won the dispersal sweepstakes. It was one of the last oceanic island groups to be populated by humans, about 900 A.D. by Polynesian travelers and in 1778 by Europeans. Relatively recent colonization by humans did not save it, however, from the biodiversity losses suffered by other isolated archipelagos—it only delayed them (Scott and others, 1988; Pratt and others, 2009a).

Go to article

Modeling The Effects Of Tile Drain Placement On The Hydrologic Function Of Farmed Prairie Wetlands1, Brett Werner, John Tracy, W. Carter Johnson, Richard A. Voldseth, Glenn R. Guntenspergen, Bruce Millett Jan 2016

Modeling The Effects Of Tile Drain Placement On The Hydrologic Function Of Farmed Prairie Wetlands1, Brett Werner, John Tracy, W. Carter Johnson, Richard A. Voldseth, Glenn R. Guntenspergen, Bruce Millett

United States Geological Survey: Staff Publications

The early 2000s saw large increases in agricultural tile drainage in the eastern Dakotas of North America. Agricultural practices that drain wetlands directly are sometimes limited by wetland protection pro- grams. Little is known about the impacts of tile drainage beyond the delineated boundaries of wetlands in upland catchments that may be in agricultural production. A series of experiments were conducted using the well-published model WETLANDSCAPE that revealed the potential for wetlands to have significantly shortened surface water inundation periods and lower mean depths when tile is placed in certain locations beyond the wet- land boundary. Under the soil conditions …

Go to article

The Porosity And Permeability Distribution Of The Shoal Grainstone And Thrombolitic Facies Of The Smackover Formation In Little Cedar Creek And Brooklyn Fields In Southwestern Alabama, Devin Thomas Jan 2016

The Porosity And Permeability Distribution Of The Shoal Grainstone And Thrombolitic Facies Of The Smackover Formation In Little Cedar Creek And Brooklyn Fields In Southwestern Alabama, Devin Thomas

Electronic Theses and Dissertations

The Smackover Formation is the most prolific hydrocarbon producer in Alabama, with the Little Cedar Creek and Brooklyn Fields being the two largest producers in Alabama. Unlike other Smackover fields Little Cedar Creek Field and Brooklyn Field production is the result of two reservoirs, known as the shoal grainstone and thrombolite (microbial) boundstone. Even with the success of the Smackover Formation, geographic trends of the porosity and permeability are problematic because production is affected. The distribution of the facies also plays a role in the porosity and permeability. The objective of this study is to delineate porosity and permeability trends …

Go to article

Eons, Eras And Periods, John J. Renton, Thomas Repine Jan 2016

Eons, Eras And Periods, John J. Renton, Thomas Repine

Readings and Notes

A discussion of eons, era, periods and epochs of the geologic time scale.

Go to article

The Silurian Period, John J. Renton, Thomas Repine Jan 2016

The Silurian Period, John J. Renton, Thomas Repine

Readings and Notes

The Silurian Period is the shortest of all the periods of the Paleozoic Era, lasting only 30 million years from 438 million years ago until 408 million years ago. As the Silurian Period opens, the eastern margin ofLaurentia was dominated by the Taconic Highlands that had been created during the Taconic Orogeny at the close of the Ordovician. The rest of the craton was essentially flat-lying and covered by a shallow sea. Except for the northeastern margin which was involved in a major orogeny following the Taconic Orogeny, Laurentia was tectonically quiet throughout the Silurian. About 10 million years before …

Go to article

The Permian Period, John J. Renton, Thomas Repine Jan 2016

The Permian Period, John J. Renton, Thomas Repine

Readings and Notes

The Permian Period was a time of great crisis in Earth's history. The Permian saw the final closure of the Iapetus Ocean that had formed following the breakup of the super­ continent of Rodinia in the late pre-Cambrian; the closure resulting in the formation of another super-continent, Pangea. It was during the Permian that two of Earth's major mountain chains, the Appalachians and the Urals, were created. The period was one of climatic extremes. By the end of the Permian, Earth had not only experienced its most widespread glaciation but also the formation of deserts the likes of which had …

Go to article

The Cretaceous Period, John J. Renton, Thomas Repine Jan 2016

The Cretaceous Period, John J. Renton, Thomas Repine

Readings and Notes

A global rise in sea level occurred during the Cretaceous; as a result, sea level stood as high during the Late Cretaceous than at any other time in the Phanerozoic history of Earth. Although Pangea had begun to breakup during the Early Mesozoic Era, the smaller continents remained tightly clustered at the beginning of Cretaceous time. The continued breakup of Pangea and the dispersion of the newly created continents were among the most important events that occurred during the global geography of the Cretaceous. Especially important was the breakup of Gondwana. Gondwana was still intact at the beginning of the …

Go to article

The Mississippian Period, John J. Renton, Thomas Repine Jan 2016

The Mississippian Period, John J. Renton, Thomas Repine

Readings and Notes

The first rocks to attract the attention of the early European were those containing the coals, primarily because of their importance in supplying the source of energy for the Industrial Revolution which began in the mid-1700s. As early as 1808, the coal-bearing rocks were referred to on the Continent as the "bituminous terraine' while the British geologists called them the "Coal Measures" The name Carboniferous was introduced in 1822 by Conybeare and Philips when they were attempting to make sense of the rocks of England and Wales. They proposed that all of the rocks from the Coal Measures down to …

Go to article

The Cambrian Period, John J. Renton, Thomas Repine Jan 2016

The Cambrian Period, John J. Renton, Thomas Repine

Readings and Notes

The Cambrian Period extends from 570 million years ago to 505 million years ago. Notwithstanding the discovery of the Ediacara fauna, the Cambrian Period of the Paleozoic Era has historically been taken as the beginning of historical time based on the first appearance of abundant fossil remains. It is interesting to note, however, that where first described, the lower Cambrian was not very fossiliferous.

Go to article

The Geology Of West Virginia, John J. Renton, Thomas Repine Jan 2016

The Geology Of West Virginia, John J. Renton, Thomas Repine

Readings and Notes

This is not meant to be a geology textbook but rather a discussion that will help you understand what you see around you every day or if you take a trip around the State. For example, you're on your way to work or to class or you are going shopping. Most likely, you're driving down a wide valley surrounded by hills. What do the hills look like? Why does the topography change as you go from one part of the State to another? In my opinion, of all the states that make up Appalachia, West Virginia is the most interesting …

Go to article

The Cenozoic Era, John J. Renton, Thomas Repine Jan 2016

The Cenozoic Era, John J. Renton, Thomas Repine

Readings and Notes

It has been said that the modem world unfolded during the Cenozoic Era. It is true that every feature of the modem landscape was formed during the Cenozoic Era. The Alps and the Himalaya have literally risen from the ocean floor. The Rocky mountains have been formed, worn away and re-uplifted to their present heights. The Appalachian Mountains that had formed at the close of the Paleozoic and worn away by the end of the Triassic, were uplifted and sculpted into their present form during the Cenozoic. All the other mountains of the world were also elevated and sculpted to …

Go to article

The Devonian Period, John J. Renton, Thomas Repine Jan 2016

The Devonian Period, John J. Renton, Thomas Repine

Readings and Notes

Until the 19th century, the rocks exposed throughout the provinces of Devonshire and Cornwall in southwestern England had long been considered to be Carboniferous in age because of their content of fossil plants. Closer investigation by Murchison and Sedgwick in 1836, however, showed that only the uppermost portion of these rocks contained fossil plants. Because the lower portion of the rock sequence was devoid of plant fossils, was highly deformed, and resembled the rocks of northwest Wales which they had recently studied, Murchison and Sedgwick assigned the rocks to the Cambrian System. However, local fossil collectors had submitted fossil corals …

Go to article

Geologic History Of West Virginia, John J. Renton, Thomas Repine Jan 2016

Geologic History Of West Virginia, John J. Renton, Thomas Repine

Readings and Notes

The exposed rocks and those that underlie the surface of West Virginia record approximately 300M years of Earth history. This may sound like a very long period of time, but in reality, it only represents about 7% of the total age of Eai1h. Before we undertake a discussion of the geologic history of West Virginia, there are some basic topics we should review in order to fully appreciate what will follow. To that end, the following topics will be discussed: 1) The Origin of Earth, 2) The Response of Rocks to Stress, 3) Some Basic Characteristics of Sedimentary Rocks, 4) …

Go to article

Nonlinear Model And Qualitative Analysis For Coupled Axial/Torsional Vibrations Of Drill String, Fushen Ren, Baojin Wang, Suli Chen, Zhigang Yao, Baojun Bai Jan 2016

Nonlinear Model And Qualitative Analysis For Coupled Axial/Torsional Vibrations Of Drill String, Fushen Ren, Baojin Wang, Suli Chen, Zhigang Yao, Baojun Bai

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

A nonlinear dynamics model and qualitative analysis are presented to study the key effective factors for coupled axial/torsional vibrations of a drill string, which is described as a simplified, equivalent, flexible shell under axial rotation. Here, after dimensionless processing, the mathematical models are obtained accounting for the coupling of axial and torsional vibrations using the nonlinear dynamics qualitative method, in which excitation loads and boundary conditions of the drill string are simplified to a rotating, flexible shell. The analysis of dynamics responses is performed by means of the Runge-Kutta-Fehlberg method, in which the rules that govern the changing of the …

Go to article

Morphodynamic Modeling Of Fluvial Channel Fill And Avulsion Time Scales During Early Holocene Transgression, As Substantiated By The Incised Valley Stratigraphy Of The Trinity River, Texas, Kaitlin Moran, Jeffrey Nittrouer, Mauricio Perillo, Jorge Lorenzo Trueba, John Anderson Jan 2016

Morphodynamic Modeling Of Fluvial Channel Fill And Avulsion Time Scales During Early Holocene Transgression, As Substantiated By The Incised Valley Stratigraphy Of The Trinity River, Texas, Kaitlin Moran, Jeffrey Nittrouer, Mauricio Perillo, Jorge Lorenzo Trueba, John Anderson

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The Trinity River system provides a natural laboratory for linking fluvial morphodynamics to stratigraphy produced by sea-level rise, because the sediments occupying the Trinity incised valley are well constrained in terms of timing of deposition and facies distribution. Herein, the Trinity River is modeled for a range of base-level rise rates, avulsion thresholds, and water discharges to explore the effects of backwater-induced in-channel sedimentation on channel avulsion. The findings are compared to observed sediment facies to evaluate the capability of a morphodynamic model to reproduce sediment deposition patterns. Base-level rise produces mobile locations of in-channel sedimentation and deltaic channel avulsions. …

Go to article

Heavy-Oil And Bitumen Resources Of The Big Clifty Sandstone, Northeastern Grayson County And Adjacent Hardin County, Kentucky, J. Richard Bowersox Jan 2016

Heavy-Oil And Bitumen Resources Of The Big Clifty Sandstone, Northeastern Grayson County And Adjacent Hardin County, Kentucky, J. Richard Bowersox

Report of Investigations--KGS

Rock asphalt (bitumen-saturated sandstone) was produced from the Big Clifty Sandstone near Tar Hill and Big Clifty in northeastern Grayson County, and at Summit in adjacent Hardin County, from 1889 to 1940. Noncommercial amounts of oil were distilled from Big Clifty rock asphalt before 1930. Resource assessments conducted throughout the area during the mid-1920's described substantial rock-asphalt deposits. Later assessments in 1951, 1965, and the early 1980's, however, overlooked the northeastern Grayson County area. A new evaluation in 2015 estimated that the historically developed area between Clifty Creek and meeting Creek, and between the Summit Fault and Eveleigh Fault Zone, …

Go to article

Aquifers Of Nebraska I: The Codell Aquifer In Northeastern Nebraska, Dana Divine, R. Matthew Joeckel, Sue Olafsen Lackey Jan 2016

Aquifers Of Nebraska I: The Codell Aquifer In Northeastern Nebraska, Dana Divine, R. Matthew Joeckel, Sue Olafsen Lackey

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Go to article

Documentation Of Extensive Root Systems Of Thalassia Seagrass Along The Banks Of Pigeon Creek, San Salvador Island, Bahamas, Bosiljka Glumac, H. Allen Curran Jan 2016

Documentation Of Extensive Root Systems Of Thalassia Seagrass Along The Banks Of Pigeon Creek, San Salvador Island, Bahamas, Bosiljka Glumac, H. Allen Curran

Geosciences: Faculty Publications

Reprinted from: Bosiljka Glumac & Michael Savarese (eds.), Proceedings of the 16th Symposium on the Geology of the Bahamas and Other Carbonate Regions: San Salvador, Gerace Research Center

Go to article

Experimental Investigation Of Fracture Width Limitations Of Granular Lost Circulation Treatments, Mortadha Al-Saba, Runar Nygaard, Arild Saasen, Olav Magnar Nes Jan 2016

Experimental Investigation Of Fracture Width Limitations Of Granular Lost Circulation Treatments, Mortadha Al-Saba, Runar Nygaard, Arild Saasen, Olav Magnar Nes

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Drilling fluid losses into fractured shales is a major challenge. Lost circulation treatments are widely applied to mitigate the losses; however, the effectiveness of these treatments is affected by different physical properties of the used lost circulation materials (LCM). This paper presents an experimental investigation to study the effect of LCM type, concentration, particle size distribution, temperature, and LCM shape on the formed seal integrity, with respect to differential pressure, at different fracture widths. The overall objective of this study is to address the effectiveness of LCM treatments in sealing fractured shales, with specific application to the over consolidated Barents …

Go to article

Coal Geology: The Origin Of Coal, John J. Renton, Thomas Repine Jan 2016

Coal Geology: The Origin Of Coal, John J. Renton, Thomas Repine

Readings and Notes

Coal forms from the tissues of plants with the major contributor being the woody tissues, cellulose and lignin, from trees growing in fresh-water wetlands. Land plants first evolved during the early Devonian and by the end of the period had adapted to most terrestrial environments. Beginning in early Pennsylvanian time, vast portions of the eastern portion of Laurentia were covered with coal-forming swamps and bogs, environments that were to be repeated throughout the remainder of the Paleozoic Era and again in the Jurassic, Cretaceous and Tertiary Periods. It was during these times that the combination of climatic conditions and wetland …

Go to article

A Geology Field Trip, John J. Renton, Thomas Repine Jan 2016

A Geology Field Trip, John J. Renton, Thomas Repine

Readings and Notes

oduction to Field Trip I had several objectives in mind when I prepared this field trip. I want to develop in you an interest, an understanding, and an appreciation of geology of the region. I want to show you differences between three of the basic physiographic provinces within Appalachia, the Low Plateau, the High Plateau, and the Appalachian Mountain Section of the Valley and Ridge Province. I also want to show you the role that the kinds and structures of the underlying rocks plays in the formation of the topography of a region in order to have you better understand …

Go to article

Adiabatic Cooling And Warming, John J. Renton, Thomas Repine Jan 2016

Adiabatic Cooling And Warming, John J. Renton, Thomas Repine

Readings and Notes

In order to understand how deserts form one needs to understand two processes called adiabatic cooling and warming.

Go to article

Kinds Of Volcanoes, John J. Renton, Thomas Repine Jan 2016

Kinds Of Volcanoes, John J. Renton, Thomas Repine

Readings and Notes

By definition, a volcano is a conical structure that builds around a volcanic vent. A volcanic vent is an opening from which molten rock and gases erupt. According to the definition, there is no size requirement. There are volcanoes that you can span with your legs while on the other hand, there is Mt. Fiji.

Go to article

The West Virginia's Valley And Ridge Physiographic Province: An Overly Simplistic Introduction, John J. Renton, Thomas Repine Jan 2016

The West Virginia's Valley And Ridge Physiographic Province: An Overly Simplistic Introduction, John J. Renton, Thomas Repine

Readings and Notes

Anyone who has driven across West Virginia has noticed major changes in the lay of the land. In the western portion of the State the landscape belongs to the Appalachian Plateaus Physiographic Province. But what constitutes a plateau? According to the Glossary of Geology, a plateau is a dissected (stream carved) upland underlain by horizontal strata. In the case of the Appalachian Plateau, it is a relatively flat to gently rolling surface with an average elevation of about 900 feet underlain by gently folded to flat-lying sedimentary rocks. But what is a physiographic province? Again, according to the Glossary of …

Go to article

Earth's Place In Space, John J. Renton, Thomas Repine Jan 2016

Earth's Place In Space, John J. Renton, Thomas Repine

Readings and Notes

I've always thought that a story should start at the beginning. Since this book is the story of Earth, we will start at the beginning. According to the astronomers, in the beginning, there was no need for geology because there were no minerals or rocks; there was no Earth; there was no Sun; there were no stars or planets. According to the astronomers, there was a time when even our present universe didn't exist. In the 1920s, the Belgian astronomer Georges Lemaitre hypothesized that everything presently contained within the entire Universe was once compressed into in a sphere he called …

Go to article

The Pennsylvanian Period, John J. Renton, Thomas Repine Jan 2016

The Pennsylvanian Period, John J. Renton, Thomas Repine

Readings and Notes

In many respects, the mountain building of the Acadian Orogeny never really came to an end. Following the collision of Avalonia with the eastern margin of Laurasia with the subsequent creation of the Acadian Highlands, Gondwana and South America, now joined together into a single continent, were approaching from the east and south respectively. Even before the continent-continent collision that would occur at the close of Permian time, the highlands of Acadia along the eastern margin of Laurasia and Llanoria along the southern margin were being maintained as uplands in response to the compressional forces generated by the converging continents. …

Go to article

The Ordovician Period, John J. Renton, Thomas Repine Jan 2016

The Ordovician Period, John J. Renton, Thomas Repine

Readings and Notes

The Ordovician Period extends in time from 505 million years ago until 438 million years ago. You will remember from our discussions of the Cambrian that the Ordovician Period of time and the Ordovician System ofrocks was suggested by Professor Lapworth as a means of solving the dilemma presented by Murchison and Sedgewick as to the "ownership" of a section of rock that both claimed when Murchison wanted to include the upper portion of Sedgewick's Cambrian System as the lower portion of his Silurian System. Sedgewick, you will remember, responded by demanding that the lower portion of his Silurina System …

Go to article

The Jurassic Period, John J. Renton, Thomas Repine Jan 2016

The Jurassic Period, John J. Renton, Thomas Repine

Readings and Notes

During the Jurassic Period, Europe was covered by a shallow sea in which a rich fauna was encapsulated in sequences of limestones and shales. These Jurassic rocks were the training ground for many of the early geologists as they began to formulate some of the basic precepts of geology. Foremost amongst these was William Smith (1769-1839) who was the first to discover how to use fossils to correlate between separated outcrops. He gained his knowledge and understanding of fossils in his profession of a surveyor and in the building of canals throughout southern England where the canals were cut into …

Go to article

First Prev Next Last