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2014

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Articles 211 - 240 of 360

Full-Text Articles in Geology

Geology – Future Continent, Joy Wulke Feb 2014

Geology – Future Continent, Joy Wulke

The Transdisciplinary STEAM+ Journal

Terra Mirabila, a multi-media presentation illustrating the geological story of Stony Creek Granite back through complex sequence of geological events that spanned some 600 million years of early history.


Seismic And Geodetic Evidence For Grounding-Line Control Of Whillans Ice Stream Stick-Slip Events, Martin J. Pratt, J. Paul Winberry, Douglas A. Wiens, Sridhar Anandakrishnan, Richard B. Alley Feb 2014

Seismic And Geodetic Evidence For Grounding-Line Control Of Whillans Ice Stream Stick-Slip Events, Martin J. Pratt, J. Paul Winberry, Douglas A. Wiens, Sridhar Anandakrishnan, Richard B. Alley

All Faculty Scholarship for the College of the Sciences

The tidally modulated, stick‐slip events of Whillans Ice Stream in West Antarctica produce seismic energy from three locations near the grounding line. Using ice velocity records obtained by combining time series from colocated broadband seismometers and GPS receivers installed on the ice stream during the 2010–2011 and 2011–2012 austral summers, along with far‐field seismic recordings of elastic waves, we locate regions of high rupture velocity and stress drop. These regions, which are analogous to “asperities” in traditional seismic fault studies, are areas of elevated friction at the base of the ice stream. Slip events consistently initiate at one of two …


The Role Of Conservation Partnerships Between Scientists And Nonprofit Agencies In Freshwater Science And Management, Robert S. Stelzer, Donna R. Kashian Feb 2014

The Role Of Conservation Partnerships Between Scientists And Nonprofit Agencies In Freshwater Science And Management, Robert S. Stelzer, Donna R. Kashian

Environmental Science and Geology Faculty Research Publications

Funding agencies and scientific researchers are finding increasingly often that partnerships with nonprofit organizations and local communities are necessary to obtain sustainable outcomes. Scientists, nonprofit organizations, community members, and managers can extract ideas from these examples to guide development of successful new partnerships. Professional scientists and the community at large, including non-profit organizations, benefit from increased engagement and power sharing.


Capacity Building In Stakeholders Around Detroit Riverfish Consumption Advisory Issues, Donna R. Kashian, Ann E. Krause, Larissa Sano, Branda Nowell, Ken G. Drouillard Feb 2014

Capacity Building In Stakeholders Around Detroit Riverfish Consumption Advisory Issues, Donna R. Kashian, Ann E. Krause, Larissa Sano, Branda Nowell, Ken G. Drouillard

Environmental Science and Geology Faculty Research Publications

The Detroit River is an international water body that has several fish consumption advisories for contaminants that affect human health and economic revenue for the USA and Canada. Despite the importance of these advisories, little progress has been made in developing effective management strategies or coordinating monitoring, research, and policy efforts between the 2 nations. We engaged 44 stakeholder organizations to in- crease community capacity on these issues for the Detroit River. We assessed capacity with key informant interviews and a network survey. Our analysis identified weak ties in information sharing and collaboration between countries. We used this information to …


Survival Of Hatchery Gulf Sturgeon (Acipenser Oxyrinchus Desotoi Mitchill, 1815) In The Suwannee River, Florida: A 19-Year Evaluation, K. J. Sulak, M. T. Randall, J. P. Clugston Feb 2014

Survival Of Hatchery Gulf Sturgeon (Acipenser Oxyrinchus Desotoi Mitchill, 1815) In The Suwannee River, Florida: A 19-Year Evaluation, K. J. Sulak, M. T. Randall, J. P. Clugston

United States Geological Survey: Staff Publications

An experimental release of 1192 hatchery-reared, individually PIT tagged, 220 days old (296–337 mm TL) Gulf sturgeon, Acipenser oxyrinchus desotoi, was undertaken in 1992 in the Suwannee River, Florida. The original objectives of the 1992 release experiment were to: (1) evaluate survival rate of cultured Gulf sturgeon in the wild vs survival rate of their wild 1992 cohort counterparts, (2) determine the differential effect of release site within the river upon long-term survival, and (3) evaluate comparative growth rates of recaptured hatchery vs captured wild 1992 cohort Gulf sturgeon. The present investigation addressed those original objectives, plus an additional fourth …


The West Tidewater Earthflow, Northern Oregon Coast Range, Barry A. Sanford Feb 2014

The West Tidewater Earthflow, Northern Oregon Coast Range, Barry A. Sanford

Dissertations and Theses

The West Tidewater earthflow, one of the largest in Oregon's history, occurred in December of 1994. The earthflow is located approximately 15 km north of Jewel, Oregon near the summit ofthe Northern Oregon Coast Range Mountains. The earthflow is 900 m long and 250 m wide, giving it a surface area of 9 ha, or 22 acres. Volume is 3.5 million m3. The earthflow occurred in low strength, well-bedded, tuffaceous, carbonaceous, micaceous, clay-rich mudstone, and very fine-grained, feldspathic, clay-rich siltstone of the lower Miocene age Northrup Creek Formation. The soil clay fractions contain up to 90% smectite with …


Spectral Induced Polarization (Sip) Response Of Biodegraded Oil In Porous Media, Gamal Z. Abdel Aal, Estella A. Atekwana Feb 2014

Spectral Induced Polarization (Sip) Response Of Biodegraded Oil In Porous Media, Gamal Z. Abdel Aal, Estella A. Atekwana

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Laboratory experiments were conducted to investigate the effect of different oil saturation (0.2- 0.8), wetting conditions (water-wet and oil-wet), and the addition of asphaltene on the spectral induced polarization (SIP) response of biodegraded and fresh crude oil in sand columns. In the water-wet case, no significant differences were observed for both the fresh and biodegraded oil and both displayed an increase in the magnitude of the phase (φ) and decrease in the magnitudes of the real (σ′) and imaginary (σ″) conductivity components with increasing oil saturation. In this instance the SIP response is most likely controlled by the conduction and …


Light Detection And Ranging (Lidar) And Multispectral Scanner (Mss) Studies Examine Coastal Environments Influenced By Mining, W. Charles Kerfoot, Martin M. Hobmeier, Foad Yousef, Sarah A. Green, Robert Regis, Colin N. Brooks, Robert Shuchman, Jamey Anderson, Molly Reif Jan 2014

Light Detection And Ranging (Lidar) And Multispectral Scanner (Mss) Studies Examine Coastal Environments Influenced By Mining, W. Charles Kerfoot, Martin M. Hobmeier, Foad Yousef, Sarah A. Green, Robert Regis, Colin N. Brooks, Robert Shuchman, Jamey Anderson, Molly Reif

Michigan Tech Research Institute Publications

There are numerous examples of past and present mine disposal into freshwater and marine coastal bays and riverine environments. Due to its high spatial resolution and extended water penetration, coastal light detection and ranging (LiDAR), coupled with multispectral scanning (MSS), has great promise for resolving disturbed shoreline features in low turbidity environments. Migrating mine tailings present serious issues for Lake Superior and coastal marine environments. Previous investigations in Lake Superior uncovered a metal-rich “halo” around the Keweenaw Peninsula, related to past copper mining practices. For over a century, waste rock migrating from shoreline tailing piles has moved along extensive stretches …


Seismotectonics Of The Northeastern Margin Of The Arabian Plate In Iraq, Wathiq Gh. Abdulnaby Jan 2014

Seismotectonics Of The Northeastern Margin Of The Arabian Plate In Iraq, Wathiq Gh. Abdulnaby

Theses and Dissertations

The objective of this research is to study the seismotectonics of the Bitlis-Zagros Fold and Thrust Belt in northern Iraq and surrounding regions. This was accomplished through studying the crustal seismic velocity structure, focal mechanism solutions, and stress pattern of the study area. The joint inversion of receiver functions and surface wave dispersion, the moment tensor inversion, and formal stress inversion of moment stress axes are among the methods used to study the seismotectonic patterns of the study area. Another goal of this study is to provide a regional velocity model and pre-computed Green's functions that can be used accurately …


Multi-Scale Neotectonic Study Of The Clear Lake Fault Zone In The Sevier Desert Basin (Central Utah), Brandon D. Heiner Jan 2014

Multi-Scale Neotectonic Study Of The Clear Lake Fault Zone In The Sevier Desert Basin (Central Utah), Brandon D. Heiner

Theses and Dissertations

A multi-scale high-resolution geophysical and geological study was conducted in the Sevier Desert, central Utah, found within the Colorado Plateau-Basin and Range Transition Zone. The region is marked by with Quaternary volcanics and faulting as young as 660 yr B.P., with many fault scarps thought to have the potential for 7+ magnitude earthquakes. Three locations within the Sevier Desert which represent three different tectonic expressions of possible faulting at the surface were selected. These include a location found within surface sedimentation, a location with surface sedimentation and sub-surface basalts and a location with basalts, at the surface with very limited …


Relationship Between Altitude And Lithium In Groundwater In The United States Of America: Results Of A 1992–2003 Study, Rebekah S. Huber, Namkug Kim, Carl E. Renshaw, Perry F. Renshaw, Douglas Kondo Jan 2014

Relationship Between Altitude And Lithium In Groundwater In The United States Of America: Results Of A 1992–2003 Study, Rebekah S. Huber, Namkug Kim, Carl E. Renshaw, Perry F. Renshaw, Douglas Kondo

Dartmouth Scholarship

Therapeutic dosages of lithium are known to reduce suicide rates, which has led to investigations of confounding environmental risk factors for suicide such as lithium in groundwater. It has been speculated that this might play a role in the potential relationship between suicide and altitude. A recent study in Austria involving geospatial analysis of lithium in groundwater and suicide found lower levels of lithium at higher altitudes. Since there is no reason to suspect this correlation is universal given variation in geology, the current study set out to investigate the relationship between altitude and lithium in groundwater in the United …


Kenyan Climate Variation Assessment Through Rainfall Anomalies And Sea Surface Temperature (Sst) Correlations, Kimberly E. Lykens Jan 2014

Kenyan Climate Variation Assessment Through Rainfall Anomalies And Sea Surface Temperature (Sst) Correlations, Kimberly E. Lykens

STAR Program Research Presentations

The diverse and varied climate of Eastern Africa’s Kenya is home to an agriculturally dependent populace, in which farmers and other related economic sectors make up the majority of livelihoods and gross domestic product. Recurring droughts and severe flooding are major concerns for local farmers and governmental entities. The purpose of this study is to identify and categorize differences in rainfall trends over Kenya and to examine relationships between seasonal rainfall anomalies of sea surface temperature (SST), with an ultimate goal to improve predictions of wet season rainfall amounts. The analysis began with data from 27 national and cooperative weather …


Relationship Of Joint Sets To Folded Diatomite Bedding Of The Miguelito Member Of The Pismo Formation In Montaña De Oro State Park, Michael Mcmahan Jan 2014

Relationship Of Joint Sets To Folded Diatomite Bedding Of The Miguelito Member Of The Pismo Formation In Montaña De Oro State Park, Michael Mcmahan

Natural Resources Management and Environmental Sciences

This study was conducted to determine if the orientations of observed joint sets in the late Miocene diatomite bedding of the exposed Miguelito Member in Montaña de Oro State Park relate to the San Andreas wrench fault compressional forces that caused folding of the formation. Strikes and dips of bedding planes and their corresponding first and second generation joint sets were gathered and compiled into a stereonet program for analysis. A cross section of the bedding plane data shows compressional antiform (fold axis oriented ~304/013) and synform (fold axis oriented ~300/001) features. Previous studies indicate post Miocene, tectonic shortening with …


Comparison Of Non-Heating Paleointensity Techniques Using Basalts From Lemptégy Volcano, France And Synthetic Magnetite-Bearing Samples, Geoffrey A. Lerner Jan 2014

Comparison Of Non-Heating Paleointensity Techniques Using Basalts From Lemptégy Volcano, France And Synthetic Magnetite-Bearing Samples, Geoffrey A. Lerner

Dissertations, Master's Theses and Master's Reports - Open

Data of the strength of Earth’s magnetic field (paleointensity) in the geological past are crucial for understanding the geodynamo. Conventional paleointensity determination methods require heating a sample to a high temperature in one or more steps. Consequently, many rocks are unsuitable for these methods due to a heating-induced experimental alteration. Alternative non-heating paleointensity methods are investigated to assess their effectiveness and reliability using both natural samples from Lemptégy Volcano, France, and synthetic samples. Paleointensity was measured from the natural and synthetic samples using the Pseudo-Thellier, ARM, REM, REMc, REM’, and Preisach methods.

For the natural samples, only the Pseudo-Thellier method …


A Surface Displacement Analysis For Volcan Pacaya From October 2001 Through March 2013 By Means Of 3-D Modeling Of Precise Position Gps Data, Brianna R. Hetland Jan 2014

A Surface Displacement Analysis For Volcan Pacaya From October 2001 Through March 2013 By Means Of 3-D Modeling Of Precise Position Gps Data, Brianna R. Hetland

Dissertations, Master's Theses and Master's Reports - Open

Volcán Pacaya is one of three currently active volcanoes in Guatemala. Volcanic activity originates from the local tectonic subduction of the Cocos plate beneath the Caribbean plate along the Pacific Guatemalan coast. Pacaya is characterized by generally strombolian type activity with occasional larger vulcanian type eruptions approximately every ten years. One particularly large eruption occurred on May 27, 2010. Using GPS data collected for approximately 8 years before this eruption and data from an additional three years of collection afterwards, surface movement covering the period of the eruption can be measured and used as a tool to help understand activity …


Evaluation Of The Evolving Stress Field Of The Yellowstone Volcanic Plateau From 1988 To 2010 From Earthquake First Motions Inversion, Elena Russo Jan 2014

Evaluation Of The Evolving Stress Field Of The Yellowstone Volcanic Plateau From 1988 To 2010 From Earthquake First Motions Inversion, Elena Russo

Dissertations, Master's Theses and Master's Reports - Open

Within the Yellowstone National Park, Wyoming, the silicic Yellowstone volcanic field is one of the most active volcanic systems all over the world. Although the last rhyolite eruption occurred around 70,000 years ago, Yellowstone is still believed to be volcanically active, due to high hydrothermal and seismic activity. The earthquake data used in this study cover the period of time between 1988 and 2010. Earthquake relocations and a set of 369 well-constrained, double-couple, focal mechanism solutions were computed. Events were grouped according to location and time to investigate trends in faulting. The majority of the events has oblique, normal-faulting solutions. …


Linking Instrumental Neutron Activation Analysis (Inaa) With Geology In The Ancestral Caddo Region, Robert Z. Selden Jr. Jan 2014

Linking Instrumental Neutron Activation Analysis (Inaa) With Geology In The Ancestral Caddo Region, Robert Z. Selden Jr.

CRHR: Archaeology

This poster illustrates the success of a novel method of INAA that was employed to reveal geochemical signatures in Caddo ceramic vessel sherds that correlate with local surficial geology. The geochemical data from the sherd assemblage were used within an exploration of potential ceramic provenance, which was successful at demarcating sherds from ceramic vessels made from clays in either the Claiborne or Wilcox Groups. Further geochemical segregation was also apparent between the Recklaw Formation in the Claiborne Group, and the Weches Formation in the Wilcox Group. These results point to a high degree of geochemical variability within the East Texas …


At The Confluence Of Gis And Geochemistry: Identifying Geochemical Correlates Of Ripley Engraved Caddo Ceramics, Robert Z. Selden Jr., Timothy K. Perttula Jan 2014

At The Confluence Of Gis And Geochemistry: Identifying Geochemical Correlates Of Ripley Engraved Caddo Ceramics, Robert Z. Selden Jr., Timothy K. Perttula

CRHR: Archaeology

In this poster, we discuss a new approach to the identification and definition of spatial trends in archeologically-recovered ceramics associated with geochemical results produced using instrumental neutron activation analysis (INAA). Using all of the Ripley Engraved INAA samples, we posit that clays in the Claiborne and Wilcox Groups can be successfully demarcated by sodium (Na), cerium (Ce), and zinc (Zn). Using a subset of those data from the Big Cypress Creek basin, we find that ceramics manufactured in three different Caddo political communities can be successfully demarcated based upon differential concentrations of arsenic (As), iron (Fe), and vanadium (V) found …


Some Reflections On Our Experiences At Sun Yat-Sen University Since 1985, Robert F. Diffendal Jr., Anne P. Diffendal Jan 2014

Some Reflections On Our Experiences At Sun Yat-Sen University Since 1985, Robert F. Diffendal Jr., Anne P. Diffendal

Robert F. Diffendal, Jr., Publications

Professor Zhang Ke, Chairman of the Department of Earth Sciences at Sun Yat-sen University, has asked us to write about some of our memories from our several visits to Sun Yat-sen University, as part of the 2014 celebration of the 90th anniversary of the founding of the university and the creation of the department. We are very pleased to do so and to include with our written comments copies of some photographs that we have taken during these visits. We have gone back through our notes, books, tourist maps, photo files, and other information that we have kept as souvenirs …


Low-Temperature Deformation Of Mixed Siliciclastic & Carbonate Fault Rocks Of The Copper Creek, Hunter Valley, And Mcconnell Thrusts, Jack R. Hoehn Jan 2014

Low-Temperature Deformation Of Mixed Siliciclastic & Carbonate Fault Rocks Of The Copper Creek, Hunter Valley, And Mcconnell Thrusts, Jack R. Hoehn

Honors Papers

This study analyzes the low-temperature deformation of fault rocks associated thrust faults. Each fault has dominantly carbonate rocks in one wall and dominantly siliciclastic rocks in the other. The rocks from the Hunter Valley and Copper Creek thrusts of the Southern Appalachians, and McConnell thrust of the Canadian Rockies, were analyzed using data extracted at the thin section and SEM scale. The rocks, all of which featured a fine-grained carbonate matrix surrounding larger carbonate and siliciclastic carbonates, all experienced general shearing, but deformed by different deformation mechanisms. The Hunter Valley and McConnell samples showed evidence of cataclasis, diffusive mass transfer, …


Petrography, Stable Isotope Compositions, Microraman Spectroscopy, And Presolar Components Of Roberts Massif 04133: A Reduced Cv3 Carbonaceous Chrondrite, Jemma Davidson, Devin L. Schrader, Conel M. Alexander, Dante S. Lauretta, Henner Busemann, Ian A. Franchi, Richard C. Greenwood, Harold Connolly Jr., Kenneth J. Domanik, Alexander Verchovsky Jan 2014

Petrography, Stable Isotope Compositions, Microraman Spectroscopy, And Presolar Components Of Roberts Massif 04133: A Reduced Cv3 Carbonaceous Chrondrite, Jemma Davidson, Devin L. Schrader, Conel M. Alexander, Dante S. Lauretta, Henner Busemann, Ian A. Franchi, Richard C. Greenwood, Harold Connolly Jr., Kenneth J. Domanik, Alexander Verchovsky

School of Earth & Environment Departmental Research

Here, we report the mineralogy, petrography, C-N-O-stable isotope compositions, degree of disorder of organic matter, and abundances of presolar components of the chondrite Roberts Massif (RBT) 04133 using a coordinated, multitechnique approach. The results of this study are inconsistent with its initial classification as a Renazzo-like carbonaceous chondrite, and strongly support RBT 04133 being a brecciated, reduced petrologic type >3.3 Vigarano-like carbonaceous (CV) chondrite. RBT 04133 shows no evidence for aqueous alteration. However, it is mildly thermally altered (up to approximately 440 °C); which is apparent in its whole-rock C and N isotopic compositions, the degree of disorder of C …


How Mangrove Forests Adjust To Rising Sea Level, Ken W. Krauss, Karen L. Mckee, Catherine E. Lovelock, Donald R. Cahoon, Neil Saintilan, Ruth Reef, Luzhen Chen Jan 2014

How Mangrove Forests Adjust To Rising Sea Level, Ken W. Krauss, Karen L. Mckee, Catherine E. Lovelock, Donald R. Cahoon, Neil Saintilan, Ruth Reef, Luzhen Chen

United States Geological Survey: Staff Publications

Mangroves are among the most well described and widely studied wetland communities in the world. The greatest threats to mangrove persistence are deforestation and other anthropogenic disturbances that can compromise habitat stability and resilience to sea-level rise. To persist, mangrove ecosystems must adjust to rising sea level by building vertically or become submerged. Mangroves may directly or indirectly influence soil accretion processes through the production and accumulation of organic matter, as well as the trapping and retention of mineral sediment. In this review, we provide a general overview of research on mangrove elevation dynamics, emphasizing the role of the vegetation …


Basalt Ring Formations Of The Columbia River Plateau, Skye Schillhammer, Carly Sorensen, Ted Uecker, Natasha Garland Jan 2014

Basalt Ring Formations Of The Columbia River Plateau, Skye Schillhammer, Carly Sorensen, Ted Uecker, Natasha Garland

2014 Symposium

Unusual basalt ring formations are located about 6 miles north of Odessa, WA as part of the expansive Columbia River Basalt Group. There are over 100 crater-like structures that range in size from 50-500 meters in diameter and span a 60 kilometer area of the channeled scablands. These structures are enigmatic due to the erosion of surficial features by the Missoula Floods, and due to their association with a magnetic anomaly as evidenced by an aerial geophysical survey. Since the 1970s, multiple geologists have proposed conflicting formational mechanisms for the rings, including hydrothermal explosions and sag flows. Over the past …


The 17 May 2012 M4.8 Earthquake Near Timpson, East Texas: An Event Possibly Triggered By Fluid Injection, Cliff Frohlich, William Ellsworth, Wesley A. Brown, Michael Brunt, Jim Luetgert, Tim Macdonald, Steve Walter Jan 2014

The 17 May 2012 M4.8 Earthquake Near Timpson, East Texas: An Event Possibly Triggered By Fluid Injection, Cliff Frohlich, William Ellsworth, Wesley A. Brown, Michael Brunt, Jim Luetgert, Tim Macdonald, Steve Walter

Faculty Publications

This study summarizes our investigation of the 17 May 2012 MW‐RMT4.8 earthquake near Timpson, Texas, the largest earthquake recorded historically in eastern Texas. To identify preshocks and aftershocks of the 17 May event we examined the arrivals recorded at Nacogdoches (NATX) 30 km from the 17 May epicenter, at nearby USArray Transportable Array stations, and at eight temporary stations deployed between 26 May 2012 and mid‐2013. At NATX we identified seven preshocks, the earliest occurring in April 2008. Reliably located aftershocks recorded by the temporary stations lie along a 6 km long NW‐SE linear trend corresponding to a …


Size-Frequency Distribution Of Orbitolina Texana Foraminifera, Jeremy Foote Jan 2014

Size-Frequency Distribution Of Orbitolina Texana Foraminifera, Jeremy Foote

Undergraduate Review

This study examined size-frequency distributions for an extinct Cretaceous-age benthic foraminifera called Orbitolina Texana in order to determine the health of this foram community during the time of accumulation. Forams were collected from limestone outcrops of the Glen Rose Formation in central Texas. Based on paleontological and sedimentological evidence, Orbitolina Texana are interpreted to be a shallow water (<10 m) benthic organism that was most abundant in back-reef environments. Sizefrequency distributions were generated from the diameters of 4,245 Orbitolina Texana fossils. The results indicate that the Orbitolina Texana population is characterized by a Gaussian (normal) size distribution. Size-frequency distributions of fossilized foraminifera in the stratigraphic record are controlled by two principle variables; environmental controls that affect the biology of the organisms (e.g., environmental stressors, like food availability and ambient conditions) and sedimentological controls that affect how the organisms are distributed (e.g., hydrodynamic parameters, like waves and currents). Based on a sedimentological characterization of the host limestone including lack of high-energy sedimentary structures, high mud content and back-reef position on the depositional profile, hydrodynamic parameters are interpreted to not have exerted a significant effect on the distribution of the forams preserved in the rock record. As such, the biological controls are interpreted to be the dominate control on the foram sizefrequency distribution. Therefore, the Gaussian (normal) size distribution suggests that the mortality rate is independent of size/age, which is classified as Type II survivorship. As this result is consistent with similar taxon, the results indicate that this Orbitolina Texana population was a healthy biologic community, despite the low biologic diversity observed in the Glen Rose Formation.


Slope Stability Analysis Of Mount Meager, South-Western British Columbia, Canada, Rachel M. Hetherington Jan 2014

Slope Stability Analysis Of Mount Meager, South-Western British Columbia, Canada, Rachel M. Hetherington

Dissertations, Master's Theses and Master's Reports - Open

The Mount Meager Volcanic Complex (MMVC) in south-western British Columbia is a potentially active, hydrothermally altered massif comprising a series of steep, glaciated peaks. Climatic conditions and glacial retreat has led to the further weathering, exposure and de-buttressing of steep slopes composed of weak, unconsolidated material. This has resulted in an increased frequency of landslide events over the past few decades, many of which have dammed the rivers bordering the Complex. The breach of these debris dams presents a risk of flooding to the downstream communities. Preliminary mapping showed there are numerous sites around the Complex where future failure could …


The Inky Story Of The Dinky Oak Gall, Ken Sulak Jan 2014

The Inky Story Of The Dinky Oak Gall, Ken Sulak

United States Geological Survey: Staff Publications

Maybe you have noticed these little spheres before – but did not give them much thought. Or maybe, you puzzled: What are these wooden pearls? How did they get there? Well, a tiny wasp, called the pea galler wasp or gallfly, Belonocnema treatae, is the culprit. The diminutive female gallfly (one of nearly a thousand species in the gall wasp family Cynipidae), about the size of a fire ant, lays eggs on a freshly budded live oak leaf in spring. When the larva hatches, it produces a chemical that induces the oak to enclose it in a protective and …


Integrating Land Cover Modeling And Adaptive Management To Conserve Endangered Species And Reduce Catastrophic Fire Risk, David Breininger, Brean Duncan, Mitchell J. Eaton, Fred Johnson, James Nichols Jan 2014

Integrating Land Cover Modeling And Adaptive Management To Conserve Endangered Species And Reduce Catastrophic Fire Risk, David Breininger, Brean Duncan, Mitchell J. Eaton, Fred Johnson, James Nichols

United States Geological Survey: Staff Publications

Land cover modeling is used to inform land management, but most often via a two-step process, where science informs how management alternatives can influence resources, and then, decision makers can use this information to make decisions. A more efficient process is to directly integrate science and decision-making, where science allows us to learn in order to better accomplish management objectives and is developed to address specific decisions. Co-development of management and science is especially productive when decisions are complicated by multiple objectives and impeded by uncertainty. Multiple objectives can be met by the specification of tradeoffs, and relevant uncertainty can …


Interpreting The Paleozoogeography And Sea Level History Of Thermally Anomalous Marine Terrace Faunas: A Case Study From The Last Interglacial Complex Of San Clemente Island, California, Daniel R. Muhs, Lindsey T. Groves, R. Randall Schumann Jan 2014

Interpreting The Paleozoogeography And Sea Level History Of Thermally Anomalous Marine Terrace Faunas: A Case Study From The Last Interglacial Complex Of San Clemente Island, California, Daniel R. Muhs, Lindsey T. Groves, R. Randall Schumann

United States Geological Survey: Publications

Marine invertebrate faunas with mixtures of extralimital southern and extralimital northern faunal elements, called thermally anomalous faunas, have been recognized for more than a century in the Quaternary marine terrace record of the Pacific Coast of North America. Although many mechanisms have been proposed to explain this phenomenon, no single explanation seems to be applicable to all localities where thermally anomalous faunas have been observed. Here, we describe one such thermally anomalous fossil fauna that was studied on the second emergent marine terrace at Eel Point on San Clemente Island. The Eel Point terrace complex is a composite feature, consisting …


Identifying Sources Of Aeolian Mineral Dust: Present And Past, Daniel R. Muhs, Joseph M. Prospero, Matthew C. Baddock, Thomas E. Gill Jan 2014

Identifying Sources Of Aeolian Mineral Dust: Present And Past, Daniel R. Muhs, Joseph M. Prospero, Matthew C. Baddock, Thomas E. Gill

United States Geological Survey: Publications

Aeolian mineral dust is an important component of the Earth’s environmental systems, playing roles in the planetary radiation balance, as a source of fertilizer for biota in both terrestrial and marine realms and as an archive for understanding atmospheric circulation and paleoclimate in the geologic past. Crucial to understanding all of these roles of dust is the identification of dust sources. Here we review the methods used to identify dust sources active at present and in the past. Contemporary dust sources, produced by both glaciogenic and non-glaciogenic processes, can be readily identified by the use of Earth-orbiting satellites. These data …