Geoscience Research Institute Field Conference for
General Conference and Division Officers
Denver, Colorado, USA
20-31 August 2006
PICTURES -- CLICK ON ANY PICTURE FOR A LARGER VIEW
- Scenery
- Rock Types --- conglomerate, sandstone, shale, limestone, gypsum ... granite, basalt, volcanic tuff ... gneiss
- Rock Layers --- thick sequences, uplifted at an angle, turbidites ... paraconformities, angular unconformities ... reefs, clastic dike, reworked clasts
- Geologic Processes --- water and wind (rain drop impressions, ripple marks, cross-bedding, badlands, stream meanders, badlands) ... glaciation, faulting and folding
- Geology and Society --- mining, coal and oil, water resources // earthquakes, flooding, landslides, meteor impact
- Paleontology (Fossils) --- dinosaurs, shells, burrows, petrified trees, leaves, stromatolites
SCENERY
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Red Rocks Amphitheater, west Denver Tilted layers of Fountain Formation are sand and conglomerate deposited from erosion of the ancestral Rocky Mountains. |
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Garden of the Gods and Pikes Peak, Colorado Springs The red Lyons sandstone layers were uplifted vertically when the Rocky Mountains were uplifted. The 14,000 foot Pikes Peak in the background is a lone Precambrian granite intrusion. |
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Limestone cliffs of Williams Canyon, just west of Colorado Springs Ordovician to Mississippian limestone forms the canyon cliffs. The limestone was dissolved to form the Cave of the Winds tourist attraction with its entrance seen on the cliff. |
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Rift Valley and part of Collegiate Peaks, Buena Vista The Rift Valley is formed by plate tectonic processes pulling the continent apart. Mt Princeton, seem in the right half of the picture, is formed from solidified granitic magma. The granite cooled, solidified, was uplifted and then overlying sediments were eroded off. |
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Leadville view Mt Elbert and Mt Massive in the distance as seen from the Silver King Inn where the tour will be staying at 10,152 ft (3100m) in the town of Leadville. Mt Elbert at 14,433 feet (4400m) is the highest mountain in the state of Colorado. |
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Leadville street scene This historic mining town has now become a tourist attraction. |
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Mt. Sopris, Carbondale The granitic magma that solidified to form this mountain was intruded below sedimentary layers that have since been eroded away on top, but still remain tilted upwards along the edges |
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Land o' Lakes viewpoint, Grand Mesa This mesa located at 10,000 feet elevation is one of the largest flat-topped mountains in the world covering 50 square miles. Hard Tertiary basalts resisted erosion to form the flat mesa. |
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Glenwood Caverns in Glenwood Springs The caverns were formed by dissolution of the limestone, The stalagtites were then formed by water dripping from the ceilings of the caverns. |
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Colorado National Monument View from Interstate-70 west of Grand Junction. Mesozoic Wingate sandstone forms most of the cliffs. These cross-bedded sandstones are interpreted to be sand dunes deposited in a desert environment. |
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Harpers Corner, Dinosaur National Monument These canyons of the Colorado Plateau were eroded by the Green and Yampa Rivers. |
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Rocky Mountain National Park The valley has been carved by glaciers between the viewpoint from Trail Ridge Road and the string of peaks in the distance along the Continental Divide. Longs Peak, the only 14,000 foot peak in the park, is the flat-topped mountain in the far distance. |
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Rock Art, Canyon Pintado south of Rangely The Waving Hands pictograph was painted using mineral coloring found naturally. These archaeological artifacts are from the Fremont Indian culture. |
ROCK TYPES
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SEDIMENTARY - CLASTIC: Conglomerate in a recent stream channel deposit, Colorado River Rd near McCoy --- Several features can be observed in the picture: Rounding of the boulders was probably caused by tumbling in a stream channel. Variation between sand layer and boulders indicates a variation in stream energy from low to high. |
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SEDIMENTARY - CLASTIC: Conglomerate of the Fountain Formation, Red Rocks Park, west Denver --- These large boulders were rounded and transported by high-energy water action as the ancestral Rockies were eroded. |
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SEDIMENTARY - CLASTIC: Sandstone of the Fountain Formation, Red Rocks Park, west Denver --- Vertical height of the picture is about 15 feet. |
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SEDIMENTARY - CLASTIC: Shale of the Green River Formation, Rt.139 near Douglas Pass --- Mud settling out of quiet water becomes hardened to form shale. Organic material gives the darker gray color to some of the layers; this oil shale is a mostly untapped energy resource. The millions of shale layers are generally interpreted to be annual layers. |
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SEDIMENTARY - CHEMICAL: Mississippian Leadville Limestone at Minturn |
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SEDIMENTARY - CHEMICAL: Pennsylvanian Eagle Valley evaporites, Rt.82 south of Glenwood Springs --- Gypsum is assumed to have formed in a hot, arid climate by evaporation of sea water in a closed basin causing the precipitation of calcium sulfate. After burial, this soft rock easily flows forming the chevron fold seen in this picture |
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IGNEOUS - INTRUSIVE: Potassium feldspar, Big Thompson Canyon --- The potassium in this mineral is often used in K-Ar (potassium-argon) radiometric dating. |
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IGNEOUS - EXTRUSIVE: Basalt cliffs, Grand Mesa --- Tertiary basalt flowed down a valley and hardened. Later erosion formed these cliffs where the hard basalt caps the mesa. Grand Mesa is an inverted valley -- what was low has now become high. |
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IGNEOUS - EXTRUSIVE: Volcanic tuff layers, Rt.34 near Grand Lake --- This volcanic ash was deposited in the Tertiary. |
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METAMORPHIC: Andalusite crystals, White Ranch Park, northwest of Golden --- These large metamorphic crystals (some a foot long) formed deep in the earth under high pressures and temperatures. |
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METAMORPHIC: Gneiss, Big Thompson Canyon --- In this high-grade metamorphic rock, the lighter colored layers melted and recrystallized between the darker colored layers. |
ROCK LAYERS
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UPLIFTED: Garden of the Gods, Colorado Springs Layers of Lyons sandstone were tilted vertically when the Rocky Mountains were uplifted. |
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UPLIFTED: Interstate-70 roadcut, west Denver A thick sequence of rock layers tilted upwards as the Rocky Mountains were uplifted. |
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UPLIFTED: Turbidite deposit near McCoy --- Deposition is by underwater mudflows. Vertical layers are due to later uplift of hardened rock. |
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PARACONFORMITY: Hanging Lake area, Glenwood Canyon An unconformity occurs between the lower Ordovician Manitou Formation and the upper Devonian Chaffee Group. [The Manitou Fm extends left horizontally from the lone tree on the sloping skyline ridge in the middle of the picture. The formation is about twice as thick as the tree is high. The Chaffee Group is about the same thickness and is the next higher layer with many tree growing along the top of it on the skyline.] Silurian sediments, supposedly representing 25 million years, are missing between them, although no evidence is found here for major erosion in the lower layer. |
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PARACONFORMITY: Whirlpool Canyon, Dinosaur N.M. The Mississippian Madison Limestone forms the cliff about a third of the way up the canyon walls to the right of the Green River. Below it is the Cambrian Lodore Formation. In between the Ordovician, Silurian, and Devonian sediments are missing. The resulting unconformity is barely discernible although it represents an alleged break of possibly 155 million years. |
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ANGULAR UNCONFORMITY: Along Interstate-70, New Castle Rock layers were deposited, hardened, uplifted at an angle, eroded flat, and then more rock was deposited on top. |
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ANGULAR UNCONFORMITY: Along Rooney Rd, west Denver |
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Pennsylvanian Minturn Formation near Minturn Limestone was deposited as fringing reefs in the middle of the geologic column according to standard interpretation. In the center of this picture, the "reef" forms the layer at the top of the cliff. Calamites tree trunks are preserved in position of growth in this formation suggesting rapid deposition. |
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Clastic dike in the Maroon Fm at Vail Pass along Interstate-70 The Maroon Fm on the west side of the Ancestral Rockies corresponds to the Fountain Fm on the east side. Both were deposited from the outwash of the erosion of the ancestral Rockies. The sand in the diagonal cross-cutting dike had not yet been turned to rock when it was intruded into a crack in the horizontal sandstone layers. |
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Reworked clasts in the Morgan Fm, Harpers Corner, Dinosaur N.M. Quartzite (metamorphosed sandstone) from the Precambrian Uinta Mountain Group was eroded, rounded during transport, and deposited in what is now the Morgan Limestone. |
GEOLOGIC PROCESSES
WATER: Raindrop impressions, Parfet Prehistoric Preserve, Golden (west Denver)
WATER: Ripple marks, Dinosaur Ridge, west Denver
WATER: Cross-bedding, Co. Rd. 301 near McCoy --- About one third of the way up the picture are beds at an angle to the main layers.
WATER: Badlands, Wasatch Formation, Rt.13 north of Rifle --- The sandstone has been eroded into badlands and teepee-shaped mounds.
WATER: Stream meanders, Horseshoe Park, Rocky Mountain National Park --- Water descending rapidly down an canyon forms a straight path, but when it arrives in an almost level valley it meanders as shown in this picture. The lower Mississippi River shows similar meanders.
WATER: Entrenched meander, Steamboat Rock at Harpers Corner, Dinosaur N.M.
WATER: Dissolution caves in the Mississippian Leadville limestone, Glenwood Canyon, Interstate-70 --- As acidic water dissolved the limestone, caves formed as seen here and sinkholes formed at the upper surface. In the standard interpretation, the ancient sinkhole land surface at the top of this formation formed a karst topography similar to what is seen in some places in Florida today.
WIND & WATER: Honeycomb weathering, Mesa Verde Fm, Rt.139 north of Grand Junction --- Freezing and thawing of wet sandstone cliffs loosens the sand grains that are then blown away by the wind.
GLACIATION: Glacially U-shaped valley and Longs Peak, Rocky Mountain National Park
GLACIATION: Moraine Park from Many Parks Curve, Rocky Mountain National Park --- Glaciers moving to the left in the picture along what are now light green meadows pushed boulders to each side into elongated hilly moraines now covered by darker colored trees.
GLACIATION: Rouche moutonee, Moraine Park, Rocky Mountain National Park --- As glaciers moved to the left in this picture, they would leaves streaks up one side of the rock mound and then pull rocks away from the small cliff face on the left.
GLACIATION: Glacial striations, Land o' Lakes view on Grand Mesa --- The horizontal scratch marks in this picture were formed as rocks embedded in the bottom of glaciers moved across this bedrock.
GLACIATION: Glacial erratics, Grand Mesa --- Moving glaciers transported these rocks from elsewhere. The rocks are much more angular and have been transported further than what would result from water transport.
GLACIATION: Layered snow at Grand Mesa --- The tour will visit the National Ice Core Laboratory in Denver. Ice cores from Greenland that are stored there show thousands and even tens of thousands of these layers that are interpreted as annual layers.
SMALL-SCALE FOLDING: S-folds in banded gneiss, Big Thompson Canyon
TECTONIC FOLDING: Large fold in gypsum layers, Sweetwater Canyon --- Folding is the result of enormous tectonic forces.
TECTONIC FAULTING: Mitten Park Fault, Harpers Corner, Dinosaur National Monument --- Spectacular vertical fault with adjacent folding of sedimentary layers in the lower left corner of the picture.
TECTONIC FAULTING: Thrust fault along Interstate-70, Silverthorne --- Younger rocks on the very bottom of this picture have been thrust under older rocks and pushed west (left) for several miles. The fault line ascends slowly from the lower right edge of the picture to beyond the center where some folding of the layers at the fault contact can be seen.
TECTONIC FAULTING: Thrust fault at Wolford Mountain east of Rt.40 north of Kremmling --- Trees take root in the older Precambrian rocks outcropping over the top half of the mountain, but do not grow in the younger Cretaceous Pierre shale outcropping over the lower half. .
GEOLOGY AND SOCIETY
ENERGY SOURCES: Uranium roll-front deposit, Turkey Creek, west Denver --- Research has been done as to method and rates of formation.
ENERGY SOURCES: Oil seep and sulfur, Turkey Creek, west Denver
ENERGY SOURCES: Pump jack near Rangely --- The Rangely Oil Field is the most productive in Colorado. Oil and gas are trapped in an anticline of the Weber sandstone.
ENERGY SOURCES: Burning Mountain, New Castle --- Burning coal seam heats up the ground so there is a horizontal bare streak across the hill that is too warm for vegetation to grow.
ENERGY SOURCES: Mesa Verde Formation, Rt.139 south of Rangely --- Coal seams in this formation ignite and burn, baking to a bright red nearby shale and sandstone layers.
MINERAL RESOURCES: Phoenix gold mine, Idaho Springs --- A mineral vein colored blue-green by copper compounds.
WATER RESOURCES: Dillon Reservoir, along Interstate-70 --- Denver's need for water has resulted in the building of several diversion tunnels bringing water from the west side of the continental divide. The more than 20-mile long tunnel from this reservoir empties into the South Platte River which runs through Denver.
CATASTROPHE - EARTHQUAKE: National Earthquake Information Center, Golden (west Denver) --- United States Geological Survey center for real-time compilation of the world's earthquakes.
CATASTROPHE - FLOODING: Lawn Lake flood outwash from Rainbow Curve, Rocky Mountain National Park
CATASTROPHE - FLOODING: Caution sign, Big Thompson Canyon --- On July 1, 1976 a flash flood killed at least 139 people and destroyed houses, bridges, and the canyon highway. Heavy rains falling in the headwaters of the Big Thompson River moved boulders as large as 20 feet across and caused the river to rise 14 feet in just a few minutes at the canyon's mouth.
CATASTROPHE - LANDSLIDE: Douglas Pass on Rt.139 north of Grand Junction --- The hummocky ground in the foreground including the lake slid down from the cliff area to the right.
CATASTROPHE - METEOR IMPACT: Colorado's newest meteorites, Denver Museum of Nature and Science --- The Cotopaxi 8.5 ounce nickel-iron meteorite was found by metal detector near Pueblo in October 2000. The Elbert stony (chondritic) meteorite, consisting of two pieces weighting 1.75 and 10 ounces, was recovered after a spectacular fireball in January 1998.
PALEONTOLOGY (FOSSILS)
Dinosaur fossil graveyard, visitor center, Dinosaur National Monument
Dinosaur trackways, west Denver --- Dinosaur Ridge with trackways in the Dakota sandstone
Tyrannosaurus rex, Denver Museum of Nature and Science
Plesiosaur skeleton, Denver Museum of Nature and Science --- A marine reptile with a small head, long neck, and powerful paddles for limbs.
Ammonite fossils, Denver Museum of Nature and Science --- Fossils of shells related to the still-living chambered nautilus.
Crinoid stems, Harpers Corner, Dinosaur National Monument
Burrows, Dinosaur Ridge, west Denver --- These tubes are assumed to be traces of animals that formed burrows on the surface of underwater sediment.
Upright petrified tree stump, Florissant National Monument
Leaf fossils, Florissant National Monument --- Rapid burial resulted in exquisite preservation of details in these and other fossils, such as insects.
Fossil palm frond, Parfet Prehistoric Preserve, Golden (west Denver)
Stromatolite layers, Lykins Formation, Red Rocks Park, west Denver --- These bands are interpreted to have formed as stromatolites, algae mats that catch sediment in concentric layers.
Reports
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