bluuebunny/crossref_metadata_2025_split huggingface dataset:
Linking deep and shallow crustal processes in an exhumed continental arc, North Cascades, Washington
Authors: Miller Robert B. , Gordon Stacia M. , Bowring Samuel A. , Doran Brigid A. , McLean Noah M. , Michels Zachary D. , Shea Erin K. , Whitney Donna L. , Wintzer Niki E. , Mendoza Morgan K. 
Published: April 2010

Abstract
The magmatic arc represented by the crystalline core of the North Cascades (Cascades core) reached a crustal thickness of &gt;55 km in the mid-Cretaceous. Eocene collapse of the arc was marked by migmatization, magmatism, and exhumation of deep-crustal (9-12 kb) rocks at the same time as subsidence and rapid deposition in nearby transtensional nonmarine basins. The largest region of deeply exhumed rocks, the migmatitic Skagit Gneiss Complex, consists primarily of leucocratic, biotite tonalite orthogneiss intruded between ca. 76-59 Ma and 50-45 Ma. Well-layered biotite gneiss is also widespread. U-Pb (isotope dilution-thermal ionization mass spectrometry) dating of zircon and monazite from trondhjemitic leucosome and biotite gneiss mesosome indicates that metamorphism and melt generation/crystallization occurred at least intermittently from ca. 71 to 47 Ma, and the youngest U-Pb dates overlap Ar/Ar (biotite, muscovite) dates, compatible with rapid cooling. Mesoscopic to map-scale, gently plunging, upright folds have hinge lines subparallel to orogen-parallel (NW-SE) lineations in the Skagit Gneiss Complex, and are as young as 48 Ma. Eocene top-to-northwest flow occurred in parts of the complex. The gently to moderately dipping foliation, subhorizontal lineation, and constrictional domains are compatible with ductile transtension linked to dextral-normal displacement on the Ross Lake fault system, the northeastern boundary of the Cascades core. On the south flank of the core, sediments were deposited in part at ca. 51 Ma in the Swauk basin and shortly afterward folded, and then intruded by 47 Ma Teanaway basaltic dikes. Extension taken up by these dikes ranges from ~10% to 43%. Extension directions from Teanaway and other Eocene dikes are arc-parallel to arc-oblique. The shallow-crustal extension direction is counterclockwise (mostly 10°-30°) to the ductile flow direction, implying decoupling of brittle and ductile crust; however, some coupling is supported by the temporal coincidence between basin formation and partial melting and ductile flow, and the upright folding of both the Skagit Gneiss Complex and Swauk basin. Arc-oblique to arc-parallel flow probably resulted in part from dextral shear along the plate margin, along-strike gradients in crustal thickness, and thermally controlled rheology.
Paleogene calderas of central and eastern Oregon
Authors: McClaughry Jason D. , Ferns Mark L. , Streck Martin J. , Patridge Karyn A. , Gordon Caroline L. 
Published: April 2010

ABSTRACT
The John Day Formation of central and eastern Oregon, contains a widespread assemblage of both ash-flow and airfall tuffs, yet only a few corresponding caldera sources have been identified in the region. Investigators have long speculated on the sources of tuffs in the John Day Formation and have suggested that these pyroclastic rocks were vented from now buried eruptive centers in or marginal to a nascent Cascade Range. Recent detailed geologic mapping in the John Day and Clarno Formations, however, indicates the presence of at least three large-scale rhyolite caldera complexes centered along the northeast-trending axis of the Blue Mountains. This field guide describes a three-day geologic transect, from the scenic high desert of central Oregon eastward across the axis of the Blue Mountains, that will examine the physical volcanology and geologic setting of the 41.50-39.35 Ma Wildcat Mountain caldera exposed along the crest of the Ochoco Mountains, the 29.56 Ma Crooked River caldera at Prineville, and the 29.8 to 28.1 Ma Tower Mountain caldera near Ukiah.
Geological and geophysical perspectives on the magmatic and tectonic development, High Lava Plains and northwest Basin and Range
Authors: Meigs Andrew , Scarberry Kaleb , Grunder Anita , Carlson Richard , Ford Mark T. , Fouch Matt , Grove Tim , Hart William K. , Iademarco Mike , Jordan Brennan , Milliard Justin , Streck Martin J. , Trench David , Weldon Ray 
Published: April 2010

ABSTRACT
A large part of the northwestern United States has undergone extensive late Cenozoic magmatic activity yielding one of the great continental volcanic provinces on Earth. Within this broader area lies the High Lava Plains province, the focus of this field guide. For our purposes, the High Lava Plains is a middle and late Cenozoic volcanic upland, contiguous with and gradational into the Basin and Range province to the south.
The High Lava Plains province of southeastern Oregon is characterized by thin, widespread Miocene-Pleistocene lava flows of primitive basalt and a belt of silicic eruptive centers. The rhyolitic rocks generally are successively younger to the northwest, describing a mirror image to the basalt plateau and rhyolite age progression of the Snake River Plain. The High Lava Plains is associated with a zone of numerous, small northwest-striking faults and lies at the northern limit of major Basin and Range normal faults. The abundant late Cenozoic bimodal volcanism occupies an enigmatic intracontinental tectonic setting affected by Cascadia subduction, Basin and Range extension, the Yellowstone plume, and lithospheric topography at the edge of the North American craton. The purpose of this field trip is to focus on the late Cenozoic lithospheric evolution of this region, through the lens of the High Lava Plains, by considering structural, geophysical, petrologic, and temporal perspectives.
A grand tour southeast from Bend to Valley Falls, north to Burns, and then east to Venator, Oregon, takes participants from the eastern edge of the Cascade volcanic arc, across several basins and ranges in eastern Oregon, and onto the volcanic plateau of the High Lava Plains. Day 1 provides an overview of Newberry Volcano and the western edge of Basin and Range, including the Ana River and Summer Lake fault zones. On Day 2, the early magmatic and extensional history of the region is explored along the Abert Rim range-front fault. Participants are introduced to the bimodal volcanism within the High Lava Plains, with focus on the Harney Basin and Rattlesnake ignimbrite event. An evening session will highlight geophysical results from the High Lava Plains, including new data from one of the largest active-source seismic experiments to be conducted in North America. Day 3 activities examine early bimodal volcanic history of the eastern High Lava Plains and the late Miocene and Pliocene subsidence history on the east edge of the Harney Basin east of Burns, Oregon.
Snowpack data collection in the Mount Hood area using SNOTEL and geomorphic events related to snowmelt
Authors: Strobel Michael L. , Lea Jon , Brunengo Matthew J. , Pedone Paul F. 
Published: April 2010

Abstract
This field trip guide describes a one-day loop from Portland eastward around Mount Hood and returning through the Columbia River Gorge. The purpose is to visit a SNOTEL (SNOwpack TELemetry) site to observe processes and instrumentation applied in automated snowpack data collection, as well as observe geomorphic features related to snowmelt in the western United States. Annual snow accumulation in the higher elevations in the western United States provides a critical source of water for irrigation, hydroelectric power generation, municipal water supplies, and recreation. Snowmelt, however, also can cause various hydrogeologic hazards, such as floods and debris flows.
Coastal geomorphology, hazards, and management issues along the Pacific Northwest coast of Oregon and Washington
Authors: Allan Jonathan C. , Witter Robert C. , Ruggiero Peter , Hawkes Andrea D. 
Published: April 2010

ABSTRACT
Development along the coasts of Oregon and Washington is threatened by a variety of natural hazards, including coastal erosion, landslides, earthquakes, and tsunamis. Property losses have increased significantly in recent years due to past land-use and management practices and an intensification of the physical processes that drive coastal change. This field trip will visit a number of sites that document or illustrate the processes that shape Pacific Northwest coastal geomorphology and create hazards, including potentially catastrophic tsunamis generated by the Cascadia subduction zone. New research documenting ocean processes (including the role of changing wave climates, storm surges, El Nino's, and sea-level rise), tsunamis, and the effects of coastal subduction caused by great earthquakes will be covered. Also examined is the human response, which includes constructing coastal engineering structures, the establishment of coastal “erosion” hazard zones, and various mitigation efforts that are being implemented to prepare for future tsunamis. The field trip concludes on the southern Washington coast at Cape Disappointment State Park adjacent to the Columbia River, where construction of the Columbia River jetties, river flow regulation, and dredging and disposal activities have affected the sediment budget of the Columbia River littoral cell, resulting in changing sediment conditions and management practices for this cell.
Tuff cones, tuff rings, and maars of the Fort Rock–Christmas Valley basin, Oregon
Authors: Brand Brittany D. , Heiken Grant 
Published: April 2010

ABSTRACT
Hydrovolcanic eruptions occur when rising magma violently fragments while mixing with shallow surface water or groundwater. These eruptions, among the most violent on Earth, generate hundreds to thousands of explosions throughout the course of an eruptive event. Each of these explosions ejects a mixture of juvenile and accidental clasts, gas, and water droplets. The solid materials either fall to the ground from tephra jets or collapse to form pyroclastic density currents (PDCs). The deposits of these eruptions build up rings of bedded tuff around the vent, recording both a wide variety of pyroclastic depositional mechanisms, and important changes in the eruptive style with time. This field trip will explore the deposits of basaltic, hydrovolcanic eruptions in the Fort Rock–Christmas Valley basin, the location of an intermittent, fluctuating, widespread Pleistocene lake (Fossil Lake). Basaltic volcanoes erupted in the center of the lake basin are characterized by Surtseyan eruptions (standing water), along the lake basin margins by maar eruptions (groundwater), and beyond the lake margin by scoria cones. The focus of the trip will be Fort Rock (Surtseyan) and the Table Rock Complex (large Surtseyan-tuff cone, large maar, and seven minor craters). This trip offers the opportunity to examine (1) settings under which explosive hydrovolcanic eruptions occur, (2) depositional characteristics that infer eruptive conditions, (3) a wide variety of pyroclastic deposits (i.e., fallout through air or a body of water, eruption-fed subaqueous sediment gravity current deposits, PDC deposits), and (4) mega-dunes (200 m wavelength dunes associated with large scale, dilute, PDCs from an energetic, mafic hydrovolcanic eruption).
Fire and water
Authors: Cashman Katharine V. , Deligne Natalia I. , Gannett Marshall W. , Grant Gordon E. , Jefferson Anne 
Published: April 2010

ABSTRACT
This fi eld trip guide explores the interactions among the geologic evolution, hydrology, and fluvial geomorphology of the central Oregon Cascade Range. Key topics include the geologic control of hydrologic regimes on both the wet and dry sides of the Cascade Range crest, groundwater dynamics and interaction between surface and groundwater in young volcanic arcs, and interactions between rivers and lava flows. As we trace the Willamette and McKenzie Rivers back to source springs high in the young volcanic rocks of the Cascade Range, there is abundant evidence for the large permeability of young lava flows, as manifested in streams that dewater into lava flows, lava-dammed lakes in closed basins, and rivers that emerge from single springs. These dynamics contrast sharply with the older, lower permeability Western Cascades terrane and associated runoff-dominated fluvial systems. On the east side of the Cascades we encounter similar hydrologic characteristics resulting in complex interactions between surface water and groundwater as we follow the Deschutes River downstream to its confluence with the Crooked River. Here, deep canyons have cut through most of the permeable part of the geologic section, have been invaded by multiple large intracanyon lava flows, and are the locus of substantial regional groundwater discharge. The groundwater and surface-water interaction in the Deschutes Basin is further complicated by surface-water diversions and an extensive network of leaking irrigation canals. Our west-to-east transect offers an unparalleled opportunity to examine the co-evolution of the geology and hydrology of an active volcanic arc.
Geothermal geology and utilization in Oregon
Authors: Lund John W. , Boyd Toni L. , Cornachione Harriet , Clark Anne Hiller , Marcus Sara A. 
Published: April 2010

ABSTRACT
This field guide is for a three-day trip from Portland to Klamath Falls, Oregon, and back, traversing many of the physiographic provinces in Oregon, including the Columbia River, the Willamette Valley, the Western and High Cascade Mountains, the High Lava Plains, and the Basin and Range. Geologic field stops on Day 1 will be made along the drive to Klamath Falls at Salt Creek Falls and Crater Lake, and will include short discussions of Oregon's geological history and a brief introduction to geothermal resources in the state. Day 2 includes an extensive introduction to geothermal resources in Oregon and how these relate to Oregon geology, with tours to examine how the Oregon Institute of Technology, the City of Klamath Falls, and several local businesses in the Klamath Falls area use a local geothermal resource. Day 3 is devoted to the return trip to Portland, and will include geological stops at Newberry Crater, Crooked River Bridge, and Mount Hood, with more discussions of geology, geothermal resources, and geothermal exploration in Oregon.
An introduction to the stratigraphy, structural geology, and hydrogeology of the Columbia River Flood-Basalt Province
Authors: Tolan Terry L. , Martin Barton S. , Reidel Stephen P. , Anderson James L. , Lindsey Kevin A. , Burt Walter 
Published: April 2010

ABSTRACT
The Miocene Columbia River Basalt Group (CRBG) covers a large part of Oregon, Washington, and Idaho and is one of the youngest and perhaps the best studied flood-basalt province on Earth. Decades of study have established a regional strati-graphic framework for the CRBG, have demonstrated the CBRG flows can be correlated with dikes and vents, have documented a wide variety of physical features within the CRBG flows, and have demonstrated that many characteristics of the CRBG are recognizable throughout its extent. Detailed studies of individual flows and their feeder dikes have allowed the development of models for the emplacement of voluminous basaltic lava flows. The interplay between the regional structure, contemporaneous deformation, preexisting topography, and paleodrainage systems helped to control the emplacement of individual CRBG flows. These features have also affected the nature of late Neogene sedimentation in the region covered by basalt flows. Finally, the distribution of sediments within the CRBG and the character of the intraflow and interflow structures have played a significant role in the development of aquifers within the CRBG. In this paper we present an overview of the regional aspects of the stratigraphy, structural geology, tectonics, and hydrogeology of the CRBG.
Factors associated with incorrect bicycle helmet use
Authors: Hagel B E , Lee R S , Karkhaneh M , Voaklander D , Rowe B H 
Published: April 2010

BackgroundIncorrect bicycle helmet use increases head injury risk.ObjectiveTo evaluate the patterns of incorrect helmet use based on unobtrusive field observations.MethodsTwo observational surveys conducted in Alberta in 2000 and 2006 captured information on cyclist characteristics, including correct helmet use. Prevalence of correct helmet use was compared across multiple factors: age, gender, riding companionship, and environmental factors such as riding location, neighbourhood median family income, and region. Poisson regression analysis was used to relate predictor variables to the prevalence of incorrect helmet use, adjusting for clustering by site of observation.ResultsAmong helmeted cyclists (n=5862), 15.3% were wearing their helmet incorrectly or were using a non-bicycle helmet. Children (53%) and adults (51%) tended to wear their helmet too far back, while adolescents tended not have their straps fastened (48%). Incorrect helmet use declined approximately 50% over the study period for children and adolescents, but 76% (95% CI 68% to 82%) in adults. Children were 1.8 times more likely to use their helmets incorrectly in 2000 compared with adults, but this effect increased to 3.9 (95% CI 2.9 to 5.4) in 2006. Adolescents were more likely to use their helmets incorrectly in 2006 compared with adults (prevalence ratio 2.76; 95% CI 1.9 to 4.02). Children and adolescents cycling alone, compared with adults cycling alone, cycling at non-school sites and cycling in Edmonton, was associated with incorrect helmet use.ConclusionsImportant factors not previously identified were associated with incorrect bicycle helmet use. This information can be used to target interventions to increase correct use.
Accuracy of self-report of on-road crashes and traffic offences in a cohort of young drivers: the DRIVE study
Authors: Boufous Soufiane , Ivers Rebecca , Senserrick Teresa , Stevenson Mark , Norton Robyn , Williamson Ann 
Published: April 2010

In order to determine the accuracy of self-report of on-road crashes and traffic offences among participants in the DRIVE study, 2991 young drivers in New South Wales, Australia who completed the follow-up questionnaire were asked whether they had been involved in an on-road crash or were convicted for a traffic offence while driving during the year prior to the survey. This information was linked to police crash data to determine the level of accuracy of self-report of on-road crashes. There was a high level of accuracy in young drivers' self-report of police recorded crashes (85.1%; 95% CI 78.2% to 92.1%) and of police recorded traffic offences (83.0%; 95% CI 79.4% to 86.6%).Results suggest that surveys may be useful tools for estimating the incidence of on-road crashes and traffic offences in young drivers. The findings are particularly relevant to jurisdictions where access to administrative data is limited.
Historical overview of exploration of Tertiary plays in the UK North Sea
Authors: BAIN J. S. 
Published: April 2010

This paper primarily discusses those Tertiary (Paleocene and Eocene) plays and trapping mechanisms that have proved successful over the 22 years to 1990 since oil was first discovered in the UK North Sea in 1969. These successful traps (both structural and stratigraphic) are illustrated by seismic sections, uninterpreted pre-drilling and interpreted post-drilling. As well as discussing these discoveries, some of the risks associated with the more subtle stratigraphic traps are addressed.
A field size distribution of hydrocarbons in place for these discoveries in the area is presented, illustrating the rewards found to date. A brief reference is made to what the future potential may be for Tertiary prospectivity in the UK North Sea.
The Alba Field: evolution of the depositional model
Authors: NEWTON S. K. , FLANAGAN K. P. 
Published: April 2010

The Alba Field; discovered in 1984 by Well 16/26-5, is situated in UK Block 16/26, approximately 225 km northeast of Aberdeen. The field overlies the Mesozoic Witch Ground Graben, south of the Fladen Ground Spur, and north of the Renee Ridge. The main field is 9 km in length, elongate along a northwest-southeast axis. Field delineation was based upon 2D seismic data, the latest of which were acquired in 1988. Sixteen wells, inclusive of sidetracks, have been drilled to appraise the 16/26-5 discovery. Annex B approval was granted in 1991, and first oil production is expected in 1993.
The Middle Eocene sands which comprise the reservoir at Alba display remarkable petrographic uniformity, and are thought to have been deposited by high-density turbidity currents. The presence of water-escape structures and sand injection features suggests rapid deposition and burial.
Previous workers have favoured deposition of the reservoir sands within an aggradational channel/levee complex. This model was reviewed by the current authors to assess possible variations of sand quality and shale distribution, and their impact on reservoir performance. A revised model, based on interpretation of a 3D seismic survey acquired in 1989, re-examination of core, and a comprehensive review of recent literature on deep-water depositional processes, proposes that high-density turbidity currents rapidly deposited large volumes of petrographically uniform sand into a previously eroded channel-like feature. The erosional and depositional processes are interpreted to have been largely independent of one another.
Jurassic exploration history: a look at the past and the future
Authors: CORDEY W. G. 
Published: April 2010

The Groningen gas discovery in 1959 was the starting point for exploration of the North Sea basin. A decade later, the Ekofisk oil discovery set into motion the exploration of the Northern North Sea.
The critical discovery on the United Kingdom Continental Shelf (UKCS) of oil in the Paleocene of the Forties Field was in 1969. This was quickly followed in 1971 by the Brent discovery of oil in Middle Jurassic sandstones. Following on from the UKCS Fourth Round acreage awards, Jurassic exploration, in what was later to become known as the Brent Province, rapidly accelerated so that in the space of some 5 years, a succession of world ranking discoveries were made. As a consequence, of the 40 billion barrels of hydrocarbon discovered in the UKCS, almost half occurs in the Jurassic.
A number of these discoveries are regarded as ‘milestones’ in Jurassic exploration: Brent, as the first Jurassic discovery, was followed by Magnus, the first discovery in deep water Upper Jurassic sediments; Brae opened up the Upper Jurassic submarine fan play; Piper, together with Claymore, were the major discoveries that presaged a string of successes in the Witch Ground Graben area in Upper Jurassic sands ranging from shallow marine to turbiditic in origin; finally, the Fulmar discovery in Upper Jurassic shallow marine sands saw the prolific Jurassic play extended into the Central Graben.
The remaining exploration potential is likely to be concentrated in the Outer Moray Firth, but more especially within the Central Graben with the Fulmar-type sands continuing to provide a main objective.
The rapidly extending 3D seismic coverage will necessitate a reappraisal of much old well data. There will be an increasing need to devise means to exploit the many Jurassic discoveries which remain undeveloped.