Field Trips Chair
Bob Raynolds
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L lunch
R refreshments
D dinner
ON overnight lodging
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Field Trips

Premeeting Concurrent Postmeeting

All trips begin and end at the Colorado Convention Center in Denver, unless otherwise indicated. Details about the precise trip itinerary are provided upon registration or you may contact the field trip leaders directly. Participants are cautioned against scheduling any tight travel connections with field trip return times, as those times are estimates, and delays in the field may occur. For a list of hotels near the airport, contact GSA.

If you register just for a field trip, you must pay a non-registrant fee in addition to the field trip fee. This fee may be applied toward meeting registration if you decide to attend the meeting. Trip fees include transportation during the trip and a trip guide.


401. Track of the Yellowstone Hot Spot:
Young and On-Going Geologic Processes from the Snake River Plain to Yellowstone

Tues.-Sat., 23-27 Oct. — FULL
Lisa A. Morgan, USGS-Denver, +1-303-273-8646, ; Kenneth L. Pierce.
The 16-Ma Yellowstone hot spot track is one of the few places on Earth where a time-transgressive suite of processes on continental crust can be seen in the volcanic and tectonic (faulting and uplift) record at the rate and direction as predicted by plate motion. Recent interest in young and possible renewed volcanism at Yellowstone along with new discoveries and synthesis of previous studies (i.e., tomographic, deformation, bathymetric, and seismic surveys) are fueling discussion as to Yellowstone's possible plume origin. This field trip will highlight various stages in the evolution of the Snake River Plain-Yellowstone Plateau bimodal volcanic province, also known as the track of the Yellowstone hot spot. Field trip stops will include the young basaltic Craters of the Moon, exposures of 12-4-Ma rhyolites and edges of their collapsed calderas on the Snake River Plain, and faulting progressing with the volcanic fields. An essential stop is Yellowstone National Park, where the last major caldera-forming event occurred 640,000 years ago and now is host to the world's largest hydrothermal field. This 3-day trip will present a quick, intensive overview into volcanism and tectonism in this dynamically active region. We will discuss origin models and examine features that may be reflective of a tilted thermal plume as indicated in recent tomographic studies. Our drive home will pass through Grand Teton National Park, where the Teton Range is currently rising in response to the passage of the North America plate over the Yellowstone hot spot.
Min: 20; max: 44. Cost US$420 (4ON, B, R)
402. River Incision Histories of the Black Canyon of the Gunnison and Unaweep Canyon: Interplay between Late Cenozoic Tectonism, Climate Change, and Drainage Integration in the Western Rocky Mountains
Cosponsored by GSA Quaternary Geology and Geomorphology Division
Wed.-Fri., 24-26 Oct.
Andres Aslan, Mesa State College, +1-970-248-1614, ; Karl Karlstrom.
Trip begins and ends in Grand Junction, Colorado.
Canyons of the Upper Colorado and Gunnison River systems provide a spectacular backdrop for discussing the interplay between late Cenozoic tectonism, climate change, and base level shifts related to drainage integration. Examination of ancient river gravels, lacustrine deposits, dated volcanic sediments (basalts, Lava Creek B ash), and canyon geometries will be used to discuss rates and patterns of late Cenozoic fluvial incision and the effects of incision on landscape development. Key questions to be addressed include (1) to what degree have glacial-interglacial cycles affected landscape development?; (2) is stream piracy, related to drainage integration, a primary driver of incision?; and (3) are the central Rockies still rising, and if so, what are the neotectonic indications and responses?
Min: 12; max: 40. Cost US$255 (2ON, L, R)
403. Cornucopia of Coal and Coalbed Gas in the Powder River Basin: From Mining and Utilization to Methane and Methanogens
Cosponsored by GSA Coal Geology Division; GSA Geobiology and Geomicrobiology Division; GSA Hydrology Division
Thurs.-Fri., 25-26 Oct. — FULL
Powder River Trip
click for larger image
Romeo M. Flores, USGS-Denver +1-303-236-7774, ; Jason D. Putnam; Margaret S. Ellis; Michael E. Brownfield; Edward L. Heffern; Gary D. Stricker.
Trip begins and ends in Gillette, Wyoming.
The Powder River Basin (PRB) in Wyoming and Montana contains abundant, thick subbituminous coals of the Paleocene Fort Union Formation. The coals are surface mined and developed for coalbed methane (CBM). PRB mines make up 35% of the total U.S. coal production, forecast to be 40% by 2030, and supplies fuel to 144 power plants nationwide. The total cumulative gas production from 19,000 CBM wells, projected to be 50,000 wells by 2020, is 2.2 trillion ft3 (since 1987). This two-day field trip to the PRB highlights exploration, development, distribution, and utilization of this cornucopia of fuel energy. Day one includes tours at the Wyodak coal mine and nearby 330 megawatt Wyodak power plant in east Gillette. Mining in the 100-ft-thick Wyodak coal bed has supplied feed coal to the power plant since 1978. Study of the feed coal provides data useful for characterizing the physical and chemical properties of the combustion products. These data make it possible to predict fly ash properties and modes of occurrence of selected trace elements in the ash. Day two includes tours at CBM facilities. Drilling operations, completed wells, gas compression, and surface water disposal complexes are examined to gain insight about CBM exploration, development, and gas acquisition in the PRB. The CBM production from 6 to10 coal beds at 200- to 2500-ft depths is >2,000,000 ft3 per day. A study of the microbial origin of the coalbed gas revealed by methanogens of coproduced water and coal reservoirs is also discussed.
Min: 10; max: 25. Cost US$290 (2ON, L, D)
404. Clastic Sedimentology, Sedimentary Architecture, and Sequence Stratigraphy of Fluvio-Deltaic, Shoreface and Shelf Deposits, Book Cliffs, Eastern Utah and Western Colorado
Cosponsored by GSA Sedimentary Geology Division; Society for Sedimentary Geology (SEPM)
Thurs.-Sat., 25-27 Oct.
Book Cliffs
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Simon A.J. Pattison, Brandon University, +1-204-727-7468, ; Paul Davies; Huw Williams.
Trip beings and ends in Grand Junction, Colorado.
The 300-km-long Book Cliffs of eastern Utah and western Colorado are dissected by numerous side canyons and reentrants providing exceptional three-dimensional (3-D) outcrop control of Campanian strata, both along depositional-dip and depositional-strike. This, combined with the near-horizontal structural configuration, makes the Book Cliffs a world-class field laboratory for studying clastic sedimentology and sequence stratigraphy. It is truly one of the few areas in the world where you can walk and drive out time-equivalent depositional units from their proximal fluvial-coastal plain environments through the shallow marine shoreface-deltaic environments and onto the shelf. These famous rocks have been used to develop, test, and refine sedimentological and stratigraphic ideas and models over the years, including the principles and concepts of sequence stratigraphy. In addition, the Book Cliffs strata are regularly used as an outcrop analog for fluvial, deltaic, and shoreface-to-shelf hydrocarbon reservoirs worldwide. This field trip will focus on the following themes: (a) sedimentology and 3-D sedimentary architecture of fluvial, coastal plain, river- and wave-dominated deltas, and shoreface-to-shelf depositional systems; (b) stacking patterns in high versus low accommodation settings; (c) distribution of reservoir and non-reservoir facies in a predictive sequence stratigraphic framework; (d) the relationship between relative sea level, shoreline position, and stratigraphic architecture; and (e) applications of outcrop analog data to the exploration and production of hydrocarbons. The trip should be of wide interest to sedimentologists, stratigraphers, oceanographers, and paleontologists in a variety of academic, government, and industry positions. The Book Cliffs arguably represent the best exposed deltaic rocks in the world.
Min: 5; max: 30. Cost US$240 (2ON, L, R)
Green River Formation
405. Stratigraphy and Sedimentology of the Green River Formation in the Piceance Basin-The Richest Oil Shale Deposits in the World
Thurs.-Sat., 25-27, Oct. — Canceled
406. Proterozoic Geology and Phanerozoic Reactivation of the Newly Recognized Grizzly Creek Shear Zone, Glenwood Canyon, Colorado
Cosponsored by GSA Structural Geology and Tectonics Division
Fri.-Sat., 26-27 Oct. — FULL
Joseph L. Allen, Concord University, +1-304-384-5238, ; Colin A. Shaw.
Mylonitized pseudotachylyte
click for larger image
This trip will examine Proterozoic mid-crustal deformation and Phanerozoic brittle reactivation in the newly recognized Grizzly Creek shear zone, central Colorado. Our recent mapping defines the Grizzly Creek shear zone (GCSZ) as a 0.6-km-thick, brittle-plastic deformation system that dips moderately to the north along the southern margin of the White River uplift. Deep canyon incision provides spectacular cross-strike exposures of Proterozoic basement beneath Paleozoic cover strata. In Proterozoic basement, the shear zone consists of a 20-m-thick basal mylonite overlain by highly strained gneisses and megacrystic granitoids, both of which host hundreds of pseudotachylyte fault veins and thin mylonite zones. Locally, part of the shear zone is defined by a strongly foliated, fine-grained granitoid cut by pseudotachylyte and ultramylonite. The presence of mylonitized pseudotachylyte in part of the shear zone suggests that seismogenic faulting and plastic flow occurred cyclically at mid-crustal depths. Kinematic indicators are consistent with top-to-the-south Proterozoic compression. The GCSZ is cut by the Phanerozoic Grizzly Creek fault, an east-west striking, north-dipping reverse fault that coincides with the hinge of a monocline that bounds the southern margin of the Laramide White River uplift. We will discuss applications of our work to understanding earthquake rupture dynamics, Proterozoic tectonics, and the Precambrian ancestry of Phanerozoic structures and fluvial incision in the southern Rockies. The trip will involve a four-mile round-trip trail hike and a steep, off-trail traverse on both days.
Min: 10; max: 20. Cost US$245 (1ON, L, R)
407. Coal Geology in the Mesaverde Group along the Eastern Edge of the Greater Green River Basin in Northwestern Colorado and South-Central Wyoming
Fri.-Sat., 26-27 Oct. — Canceled
408. Geoarchaeology of the Clary Ranch Paleoindian Sites, Western Nebraska
Fri., 26 Oct.
Nebraska Arch
click for larger image
David W. May, University of Northern Iowa, +1-319-273-6059, ; Dave Rapson; Matthew G. Hill.
This trip will visit two late Paleoindian sites in the Ash Hollow drainage, a major tributary to the North Platte River in western Nebraska. These two sites are contemporary and are believed to represent complementary dimensions of a single settlement and subsistence system. One is a bison processing area; the other a camp. Emphasis will be on interdisciplinary research in the basin and at the sites, including geomorphology and early Holocene stratigraphy in the basin, paleoenvironmental reconstruction using several lines of evidence, and Paleoindian archaeology. A visit to a local museum (Ash Hollow Cave) is included as well.
Min: 22; max: 40. Cost US$105 (L, R)
409. From Buttes to Bowls: Repeated Inversions in the Landscape of the Colorado Piedmont
Cosponsored by Colorado Geological Survey; Colorado Scientific Society
Fri., 26 Oct. — FULL
Matthew Morgan, Colorado Geological Survey, +1-303-866-2066, ; Vincent Matthews III.
Mesas and buttes of the central Colorado Piedmont are composed of at least two distinct rock types that differ in their cohesiveness and ability to withstand erosion. The lower parts are friable, early to middle Paleogene sandstones of the Dawson Formation. The caprock is composed of one or more resistant formations: Castle Rock Conglomerate, Wall Mountain Tuff, and Larkspur Conglomerate — all of late Paleogene age. These formations were originally deposited in topographic lows. The lower slopes of the buttes are armored with colluvium composed of fragments of the capping units, and commonly form relict faceted slopes. Once the caprock of a butte or mesa has been removed by erosion, the poorly consolidated Dawson Formation quickly erodes out of the center. This leaves the armored lower slopes of the former butte as an erosionally resistant, circular ridge standing as much as 100 m above the surrounding topography. This process produces a topographic low where the peak of the butte once stood. Some buttes have prominent alluvial fans that record the main phase of butte removal and excavation of the central part of the armored slopes. Soil profiles and height above modern streams indicate the oldest preserved gravel deposit is of middle Pleistocene age; the youngest alluvial fans were deposited during the Holocene. This field trip will visit key outcrops between Larkspur and Sedalia, Colorado, that display the anatomy of colluvium rings and armored slopes. We will also discuss their methods of formation, preservation, and rates of erosion.
Min: 5; max: 20. Cost US$110 (L, R)
410. The Beautiful Vail Valley: A Classroom in Geologic Hazards and Mitigation
Cosponsored by Colorado Geological Survey
Sat., 27 Oct.
Vail Valley
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Vincent Matthews III, Colorado Geological Survey, +1-303-866-3028, ; Jonathan White, Colorado Geological Survey.
The beautiful, glaciated Vail Valley has a variety of geological hazards. Land-use decisions relative to mitigation of these hazards are also quite varied. Several excellent examples of the consequences of following recommended mitigations, as well as examples of the consequences of ignoring recommended mitigations, will be pointed out on this trip.
Min: 12; max: 45. Cost US$75 (L, R)
411. Geology of the Cripple Creek Gold-Telluride Deposit, Colorado
Cosponsored by Society of Economic Geologists; International Geological Correlations Program
Sat., 27 Oct. — FULL
Paul G. Spry, Iowa State University, +1-515-294-9637, ; Eric P. Jensen.
This trip will focus on the geological setting of one of the largest gold deposits in North America: Cripple Creek and its surrounding environs. The emphasis will be on the host rocks, hydrothermal alteration, and structural relations of the precious metal mineralization. Planned stops include the lodes and attendant hydrothermal alteration in the operating pit at Cripple Creek, and surface exposures of the Cripple Creek Diatreme Intrusive Complex. Participants will see the spatial-genetic relations among gold mineralization, breccias, and alkaline igneous rocks.
Min: 10; max: 30. Cost US$85 (L, R)
412. Geoarchaeological Context of Paleoindian Sites in Middle Park, Colorado
Cosponsored by GSA Archaeological Geology Division
Sat., 27 Oct.
Middle Park
click for larger image
James H. Mayer, University of Arizona, +1-520-400-6470, ; Todd A. Surovell.
Geoarchaeological investigations have been carried out in Middle Park as part of ongoing research by the University of Wyoming Dept. of Anthropology, with the primary goals of (1) defining the soil and stratigraphic context of the Paleoindian occupation; (2) determining processes and patterns in Holocene landscape evolution potentially modifying the Paleoindian record; and (3) understanding components of the landscape most likely to yield in situ Paleoindian sites. We will visit two localities subjected to fairly detailed geoarchaeological inquiry: Barger Gulch Locality B, a Folsom campsite, and the Jerry Craig site, a Cody Complex bison kill. Both sites have yielded in situ Paleoindian components associated with buried forest soils in settings currently dominated by sagebrush, thus providing insights into Holocene landscape evolution and paleoenvironmental change. Three to four hours will be spent at Locality B, where the most extensive archaeological and geoarchaeological work has been carried out. Profiles in the upland excavation block, exposure in a low-order tributary gully, and alluvial exposures along Barger Gulch proper will be examined. At Jerry Craig, we will spend one to two hours examining an exposure in the excavation block, as well as a road cut. Discussion at both sites will concentrate on geomorphic histories, with special attention to the soil stratigraphic records. Site records will be compared to other non-archaeological settings examined in Middle Park. Finally, the Middle Park geoarchaeological records will be compared with well-documented glacial, pollen, and fossil insect records from higher elevations in the Colorado Front Range.
Min: 10; max: 40. Cost US$79 (L, R)
413. Fish, Turtles, Plants, and Insects within the Morrison Formation: A Walk through a Late Jurassic Ecosystem
Sat., 27 Oct.
click for larger image
Mark A. Gorman II, University of Colorado, +1-303-786-0999, ; Jason Pardo; Bryan Small; Ian Miller.
This will be a four to five hour walk and drive through a lacustrine (lake) Morrison deposit outside Canon City, Colorado. We will be looking at fish, plant, and insect localities excavated over the past four years that allow for a unique look at a Late Jurassic ecosystem. Some additional highlights will be large angular granitic clasts in the basal member of the Morrison and an unconformity located between the Morrison and the crystalline rock below.
Min: 5; max: 20. Cost US$110 (L, R)
414. Hydrology and Geochemistry of the Boulder Creek Watershed
Cosponsored by U.S. Geological Survey; GSA Quaternary Geology and Geomorphology Division
Sat., 27 Oct. — FULL
Boulder Creek
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Philip L. Verplanck, USGS-Denver +1-303-236-1902, ; John Pitlick; Peter W. Birkeland; Sheila F. Murphy; Larry B. Barber; Travis Schmidt.
This is a bicycle field trip exploring the hydrology and geochemistry of Boulder and South Boulder creeks. Topics include flood frequency and hazards, aqueous geochemistry of the watershed, and potential impacts of invasive species and emerging contaminants on stream ecology. The Boulder Creek watershed is an ideal natural laboratory for integrated research and educational outreach because of natural and land-use gradients and the proximity to research and educational facilities. This sixteen-mile trip at stream gradient will be on rented bicycles primarily using city of Boulder paved trails.
Min: 12; max: 30. Cost US$66 with bike rental; US$45 with own bike (L, R)
415. From the Crest of the Front Range to the Depths of the Denver Basin
Sat., 27 Oct.
Shari Kelley, New Mexico Institute of Mining and Technology, +1-505-661-6171, ; Robert Raynolds.
This one-day trip will travel from the top of Mount Evans to the center of the Denver Basin. Discussion will focus on exhumation of the Front Range, based on low temperature thermochronology, and associated sedimentation in the Denver Basin, based on detrital thermochronology and depositional patterns. We will explore the implications of these results for paleo-reconstructions of past landscapes.
Min: 8; max: 22. Cost US$89 (L, R)
416. The K-T Boundary and Associated Volcanic Tuffs at West Bijou Creek, Denver Basin
Cosponsored by EARTHTIME
Sat., 27 Oct.
KT Boundary
click for larger image
Kirk R. Johnson, Denver Museum of Nature & Science, +1-303-370-6448, ; Samuel Bowring.
This one-day trip will visit the West Bijou Creek exposure of the K-T boundary, which is located 40 miles east of Denver in the center of the Denver Basin. This boundary section contains all of the classic indicators of the K-T boundary including Cretaceous and Paleocene plant and vertebrate fossils, evidence of magnetic polarity subchron C29r, anomalous iridium concentrations, shocked minerals, and a negative carbon isotope excursion. In addition, the 40-m section that contains the K-T boundary also contains a number of volcanic tuffs, some that closely bracket the K-T boundary and provide the opportunity to increase the precision on the age of the K-T boundary. This outcrop is under detailed study as part of the ongoing EARTHTIME initiative. Our trip will allow examination of several different tuffs with a range of outcrop attributes and discussion of their field expression, mineralogy, and geochronology. Trip participants will be able to observe fossils and tuffs in their stratigraphic context and see the results of integrated paleontological, geochemical, and geochronological analyses. Collecting of samples will not be allowed.
Min: 15; max: 47. Cost US$70 (L, R)


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