Here’s a look back at some of our field trips over the years!
Geologic Wonders of the Hart(sel) of South Park
June 25, 2017
Leader: Peter Barkmann, Colorado Geological Survey
This field trip explored the wonders of the Hartsel area starting with a look at the Precambrian granodiorite and its cross-cutting pegmatite sheets. We then saw the onlap of the Late Paleozoic central Colorado trough sediments onto the ancestral Front Range highland and the Garo Sandstone healing cover. Our transect then looked at the Laramide synorogenic South Park Formation with its complex stratigraphic story. Last but not least was the Neogene transformation from compression to extension with a fascinating story of Neogene tectonic closure of intermontane fluvial systems and progressive integration and incision driven by middle to late Pleistocene glacial episodes.
This all-day trek around Hartsel visited about 12 sites, with most requiring minimal off road scrambling. There was an overnight option to stay at the historic Hartsel Springs Ranch about 2 miles east of town at the confluence of the South and Middle Forks South Platte River. Peter Barkmann’s field trip notes and a map of the sites visited are attached. Please respect private property when visiting these sites. (The barite mine is on private property.)
New discoveries of dinosaur tracks & markings at Dinosaur Ridge, Morrison CO
June 18, 2016
Leader: Dr. Martin Lockley
Several of Martin’s new discoveries here have been in the news; he’ll show them to us for creative discussion and debate!
Basement hosted sandstone dikes of the Colorado Front Range
June 25, 2016
Basement hosted sandstone dikes of the Colorado Front Range: structural and other field relations, and contemplation of origins
Leaders: Christine Smith Siddoway, Colorado College, and Scott Lundstrom, USGS
New research in the southern Front Range reveals a Neoproterozoic ancestry for some of the range-bounding faults, due to their association with basement-hosted sandstone dikes that indicate Neoproterozoic age , based on detrital zircon (DZ) sedimentary provenance that includes characteristic components from the Grenville Orogen. Informally named Tava sandstone, DZ data indicate that the sandstone dikes and other large associated fault-bounded bodies formed during the Cryogenian Period, and as such the Tava sandstone provides a ‘waypoint’ in the vast span of time between emplacement of the Pikes Peak Granite at ~1.1 Ga and the deposition of Cambrian Sawatch Sandstone upon the Great Unconformity. In other words, it offers access to exploration of paleoenvironments that previously have been inconceivable.
Sandstone injectites are formed by liquefaction, remobilization and intrusion of sand into fractures within host rock, that in most circumstances involves upward injection from buried sands into overlying sediments/sedimentary rocks in active sedimentary basins. Hence the occurrence in Colorado of detrital, nonmetamorphosed injectites within crystalline basement is distinctive, and may require different geological circumstances for downward injection. The sedimentary injectites likely are a product of ’natural fracking’ of the sort that may have been achieved by large magnitude earthquakes, transient subglacial hydraulic conditions of large ice sheets, or regional scale mass wasting (rock slab failure) — possibilities that we hope to explore with CSS members who participate in the field trip.
Exposures of Tava sandstone along the Ute Pass Fault system may be found from Penrose, CO in the south, northwestward to Pine, CO, but this trip will focus on accessible sites near Buffalo Creek, and then proceed to Crystola and Manitou Springs where large associated sandstone bodies can be examined. The road-side stops require no hiking, but the Crystola and Manitou Springs stops (the latter only if there is time) involve hikes upslope, over rough terrain.
 Siddoway, C.S. and Gehrels, G.E. (2014) Basement-hosted sandstone dikes of Colorado: a vestige of the Neoproterozoic revealed through detrital zircon provenance analysis: Lithosphere 6(6): 403–408 doi:10.1130/L390.1
Green Mountain kimberlite pipe, Boulder Colorado
July 27, 2013
Leader: Pete Modreski
A short day hike to visit the most accessible and best exposed kimberlite pipe in Colorado. The Green Mountain kimberlite is located within Boulder Open Space and Mountain Parks, between Flagstaff Mountain and Green Mountain. The hike to the site, starting at the “Realization Point” trailhead, is only about one mile each way, mostly via the Ranger and Greenman trails, but it does involve negotiating a fairly steep grass/dirt hillside off-trail to cross a side valley to the kimberlite outcrop. Total elevation climb on the hike is about 500 feet. The pipe forms a good outcrop, about 140 feet in diameter, surrounded by Boulder Creek Granodiorite. This pipe, age about 600Ma (?), is the southernmost kimberlite of the State Line Kim-berlite District, and is the only kimberlite of the district in which diamonds have not been confirmed to have been found. The classic kimberlite indicator minerals, pyrope garnet, chrome diopside, and magnesian ilmenite, can be seen in the rock.
Recap of the Field Trip:
CSS Summer Field Trip by Pete Modreski
About 24 of us met in Boulder the morning of July 27 to hike to the Green Mountain kimberlite pipe. Our CSS folks were joined by some members of the Floris-sant Scientific Society. We had a pleasant hike up through the woods, everyone reached the pipe (and made it back too), and this group photo shows our crowd, all sitting/standing on the small knob formed by the outcrop of the pipe, which underlies the small clearing within the otherwise mostly forested mountainside. We were back at the Realization Point trail-head at 1 p.m., just as promised. A few of us enjoyed a side stop on the drive back down from Flagstaff Moun-tain; a rhyodacite sill intruded into the Fountain For-mation, nicely exposed at the Crown Rock trailhead.
July 2012: “Family Friendly” CSS Field Trip
On Saturday, July 21, about 15 CSS members and friends (including a couple of children) met to collect pegmatite minerals near Harris Park, Colo. Our destination was pegmatite mining claims belonging to the Littleton Gem and Mineral Club, and our visit was courtesy of that club. CSS President Pete Modreski (also a member of the Littleton mineral club) led the trip. The site is at about 9000’ elevation in Pike National Forest, north of US-285, and lies at the foot of the “Pegmatite Points” ridge east of Rosalie Peak. It lies within an offshoot of the Pikes Peak batholith, formerly known as the Rosalie Lobe (until it was discerned that the granite on Mt. Rosalie is really part of an older pluton) and now called the Lone Rock pluton, believed to be a cupola connected to the main Pikes Peak batholith at depth. Small pegmatite dikes cut through the granite on the wooded hillsides, and are host to crystals of smoky quartz and microcline; some of the feldspar is the blue-green variety, amazonite, for which Colorado is famed for among mineral collectors. Associated minerals can include albite, fluorite, topaz, goethite, hematite, and others.
A few people in the group found good specimens of quartz crystals, some of which were smoky and some not, plus microcline crystals and small amounts of fluorite. The elusive amazonite wasn’t much in evidence, beyond a few cleavage scraps left behind from previous “digs,” nor was any topaz found. But it was a beautiful day and all had a good time, and the small creek to ford just before reaching the claim site proved passable for everyone’s vehicles!
President’s Message, by Pete Modreski
June 2012: Cumbres & Toltec Scenic Railroad offers Geology Train Excursion!!
On Sunday, June 24, the Cumbres & Toltec Scenic Railroad operated a special train from Antonito, Colorado, to Chama, New Mexico, specifically for geologists. This train stopped at many outcrops and cuts along the right of way to allow geologists to mingle, take photographs, and collect rock samples.
CSS 2011 Fall Field Trip
Late Cenozoic Evolution of the Colorado with optional bike trip down Glenwood Canyon
The Grand Loop Field Trip—A Tribute to Bruce Bryant
The Victor Mine
Front Range Geology
Click here for a PDF with additional information
Amazonite-bearing pegmatites in the Pikes Peak Batholith,
near Harris Park, Park County, CO
New Insights into the Geologic and Geomorphic Evolution of South Park Basin
Trip to the northern Never Summer Range volcanic field —
“The search for Braddock’s Caldera”
Ancient Lake Alamosa
Mining History of Colorful Central City
Florissant Fossil Beds National Monument
CSS Fall Field Trip to the Paradox Basin
September 29-October 1
The 2006 Fall Field Trip for the Colorado Scientific Society was to the Paradox Basin, on September 29- October 1, 2006. The trip leader was Don Rasmussen, who has worked in the Basin for more than 30 years and has led numerous field excursions for universities and industry into the region. The trip began and ended in the La Quinta Hotel parking lot in Moab, Utah.
Trip Leaders: Bruce Bartleson and Alan Stork. Western State College; and Pete Modreski, USGS
September 22-25, 2005
The 2005 CSS fall field trip was to the Gunnison/Crested Butte area in central Colorado. The first day included traveling to Gunnison, then a half-day tour of the Powderhorn carbonatite. The second day’s topic was the structure of the Ancestral and Laramide Rockies as seen in the Elk Mountains near Crested Butte. Stops for the second day included discussions of the structures around Almont and Jack’s Cabin, Crested Butte/Gothic, and Schofield Park. We went on a hike up to Schofield Basin and the Hasley Pass area to see an excellent view of the Elk Range thrust fault. The third day’s topic was the Tertiary volcanism and igneous activity in the Gunnison Basin. Stops will include the Ohio Creek valley to see the West Elk laccolith cluster and a series of 10 Ma basalt flows on Red Mountain. We will also see the ash-flow tuffs from the San Juans near Blue Mesa Reservoir and a drive up Red Creek to a great view of the 30 Ma West Elk Volcano. The fourth day included the travel back to Denver with stops along the route.
Western State College hosted the 2006 Rocky Mountain Section Meeting of the GSA. The CSS fall field trip was be a preview of some of the field trips associated with this meeting.
South Platte Country field trip, white Cloud Pegmatite + the 1996 Buffalo Creek fire and flood
Led by Pete Modreski
June 11, 2005
Some Fieldtrip Images
A field trip to visit (1) the White Cloud Pegmatite, part of the South Platte Pegmatite District within the Pikes Peak Batholith, and (2) to see erosion, sedimentation, and ecological recovery in the aftermath of the June 1996 Buffalo Creek forest fire and flash flood. The trip will involve a 2-3 mile (round trip) hike beginning at the Colorado Trail footbridge just south of the confluence of the North and South Forks of the South Platte River. The hike will take us partly on the Colorado Trail, off-trail down a steep 400′ hillside, and downstream along the wide gravel bed of Spring Creek.
Led by Dr. Brian Penn
May 14, 2005
Some Fieldtrip Images
Buffalo Creek file trip, June, 2005
Volcanic and Plutonic rocks of Table Mountain
Led by Harald Drewes
April 23, 2005
Southward view showing the Ralston “dikes” and North and South Table Mountains.
The lava flows capping the Table Mountains are thought to have originated from Ralston dikes.
Symposium Field Trip: The Tectonics and Precambrian Geology of the Front Range between Golden and Marshall
Led by Robert J. Weimer and Lisa A. Lytle
Colorado School of Mines
Sunday, 4 April 2004
The Colorado Scientific Society is presenting a field trip in conjunction with the Symposium of the Geology of the Front Range. The field trip will examine the tectonic features along the margin and some of the Precambrian features of within the Front Range between Golden and Marshall. Bob Weimer and Lisa Lytle are the primary field trip leaders, and speakers from the symposium are encouraged to provide additional commentary.
The first 2003 Colorado Scientific Society brown-bag field trip was held on Saturday, June 21. The trip examined the Upper Cretaceous, lower Paleocene, and early Eocene rocks of the Denver Basin; it was led by Bob Raynolds of the Denver Museum of Nature and Science. Bob vividly linked the stratigraphy, tectonics, and groundwater resources of these rocks into a comprehensive story of the Laramide development of the Denver Basin and the Front Range. Highlights of the trip included a grand overview at Daniels Park, a climb to another spectacular overlook on Wildcat Mountain, a walk into the depths of Castlewood Canyon, and finally a view of the lower Eocene paleosol near Parker. The trip’s 19 participants enjoyed the first non-rainy Saturday in June.
Field trip to the northern San Juan Volcanic Field, Sept. 2003
Field trip led by Peter Lipman. Get field guide here: Field Trip to Northern San Juan Volcanic Field
Jackson Hole, Wyoming
Hayden survey sketch of Teton Valley from Upper GrosVentre Butte.
The Fall 2002 Field Trip for the Colorado Scientific Society will visit Jackson Hole, Wyoming. Not only is Jackson Hole and the Teton Range one of the most spectacular landscapes in the United States, but this trip will be at a time when the fall colors should still be in all of their glory. The field trip leaders will be Ken Pierce, Jack Reed, and Lisa Morgan, all of the U.S.G.S. Ken (past president of the CSS) has worked out a detailed glacial history of the valley. Jack Reed (another past president) has studied the Precambrian rocks of the Teton Range, and is currently working with J. D. Love on the second edition to the geologic guide, the Creation of the Teton Landscape. Lisa Morgan has been investigating the Tertiary geology of Jackson Hole, and has determined the timing of the rise of the Teton Range. All three leaders are now experienced field trip guides, and will provide an excellent learning experience. The trip will be from Friday, 20 September to Monday, 23 September.
Field trip to the Pawnee Buttes, 1999
Led by Emmett Evanoff. Get field guide here: Rocks and Faunas, Ogallala Group, Pawnee Buttes Area, Weld County, CO