May 162017
 

The Association of American State Geologists announced that their annual John C. Frye Memorial Award for 2017 is granted to the CGS and the staff members who authored the report The West Salt Creek Landslide: A Catastrophic Rockslide and Rock/Debris Avalanche in Mesa County, Colorado (CGS Bulletin-55). Utilizing a rich field data set, the report includes a comprehensive review of the geologic history of the area and presents a detailed timeline of the events surrounding the “the longest landslide in Colorado’s historical record.”

White, Jonathan L., Matthew L. Morgan, and Karen A. Berry. “Bulletin 55 - The West Salt Creek Landslide: A Catastrophic Rockslide and Rock/Debris Avalanche in Mesa County.” Bulletins. Golden, CO: Colorado Geological Survey, 2015. Bulletin 55.

White, Jonathan L., Matthew L. Morgan, and Karen A. Berry. “Bulletin 55 – The West Salt Creek Landslide: A Catastrophic Rockslide and Rock/Debris Avalanche in Mesa County.” Bulletins. Golden, CO: Colorado Geological Survey, 2015. Bulletin 55.

History of the Award:

Environmental geology has steadily risen in prominence over recent decades, and to support the growth of this important field, the Frye Award was established in 1989 by GSA and AASG. It recognizes work on environmental geology issues such as water resources, engineering geology, and hazards.

John C. Frye joined the US Geological Survey in 1938, he went to the Kansas Geological Survey in 1942, he was its Director from 1945 to 1954, he was Chief of the Illinois State Geological Survey until 1974, and was Geological Society of America Executive Director until his retirement in 1982, shortly before his death. John was active in Association of American State Geologists and on national committees, and was influential in the growth of environmental geology.

The Award is given each year to a nominated environmental geology publication published in the current year or one of the three preceding calendar years either by GSA or by a state geological survey. A shared $1000 prize and a certificate to each author is presented at the AASG Mid-Year meeting, held Tuesday morning at the GSA annual meeting.


Citation: White, Jonathan L., Matthew L. Morgan, and Karen A. Berry. Bulletin 55 – The West Salt Creek Landslide: A Catastrophic Rockslide and Rock/Debris Avalanche in Mesa County. Bulletins. Golden, CO: Colorado Geological Survey, 2015. Bulletin 55.
May 152017
 

Can you name the features of the endless Rocky Mountain skyline as seen from the Front Range? Where are they actually located? The OF-16-03 Colorado Rocky Mountain Front Profiles poster is the key to finding out. Similar profiles created in the past featured approximate or artistic interpretations of the many summits. This poster accurately locates the elevation points as they exist in geographic space.

The CGS is proud to present this unique perspective of the dramatic Front Range of Colorado as a large 54×28 in (137×71 cm) poster offset-printed on premium glossy stock. The author and designer of this special edition poster, Larry Scott, is a long-time member of the CGS staff. A talented illustrator, he handles the design work on our maps, books, pamphlets, posters, and other print material. This special project is the realization of his long-standing interest in Colorado topography.

The elevation profiles are drafted horizon lines of the heights of the Continental Divide eastward towards the High Plains. Each mesa, hogback, hill, mountain top, and points in between were plotted by intersecting its specific elevation with its latitude. The relative viewing elevation is about 9,500 ft (2900 m), the halfway point of the vertical scale. This allows one to see what cannot typically be seen from ground-level along the Front Range. If you’ve ever flown into/out of Denver International Airport — altitude 5430 ft (1655 m) — and are sitting on the west side of the plane, this is what you might see a few minutes after taking off or before landing. From this vantage, many of the great mountain ranges of central Colorado to come into view; the Sangre de Cristo, the Sawatch, the Mosquito, and others up to and occasionally beyond the Continental Divide.

Below the three profiles are 32 selected highlights of notable geographic, historic, and geologic locations as indicated via numbered circles. Many of these cite special locations for viewing the various peaks and summits. For example, on a clear day in Denver — something that happens around 300+ days a year — a perfect place to see the mountain horizon is from City Park on the west steps of the Museum of Nature and Science. At an elevation of 5,500 ft (1675 m), this panoramic vista includes much of the Front Range with the downtown Denver skyline in the foreground.


From the Explanation:

Each profile is a one-degree section beginning in the south at 37° 42′, the central section at 38° 42’, and the northern section at 39° 42’. As the south-north extent of Colorado lies between 37° and 41° latitude, these profiles represent three-quarters of the Colorado Rocky Mountain Front Range. This refers the region of mountains that descend to the plains from the Pikes Peak massif in the south, north to the Wyoming border and inclusive of all summits east to the Continental Divide. South of Pikes Peak, the mountains begin to trend southwesterly all the way to Cañon City where the Arkansas River cuts through the Royal Gorge and flows out onto the piedmont. South of Cañon City, the Wet Mountains form a barrier that drops to the plains along Interstate-25 (I-25). Further south, though not shown, the mountains lay more to the west in a broad stretch, dramatically reappearing in the form of the Spanish Peaks, which extend eastward from the spine of the southernmost Sangre de Cristo Mountains in Colorado, the Culebra Range. To the north, beyond Rocky Mountain National Park, the mountains descend steadily to the Cache la Poudre River, marking the terminus of the Northern Section.

An excerpt:

Clear Creek Canyon — Long before there was an I-70 to access the high country there were only Native American foot trails along Clear Creek. In 1858, after trace amounts of gold were discovered in Cherry Creek south of Denver, gold seekers soon began looking in the mountains. Early in January 1859, George Jackson found gold at “Jacksons Bar”, where Chicago Creek joins Clear Creek in present-day Idaho Springs. The “gold rush” was on and the canyon became the gateway to the mining camps, most notably those in the Central City area via North Clear Creek. The Colorado Central Railroad (1871-1939) occupied the canyon in those days, later becoming the roadbed for US-6. The road was not completed in the canyon until 1952 due to political infighting and the time needed to complete six tunnels in the narrow spots. Rockfall remains a constant threat along the Canyon, with a notably large event closing the road in the summer of 2005 for almost three months—the longest full-road closure in state history.


Citation: Scott, Lawrence. OF-16-03 Colorado Rocky Mountain Front Profiles. Profile. Open File Report. Golden, CO: Colorado Geological Survey, May 2017.
May 132017
 

We’ve decided to revive one of our most popular print publications — RockTalk — as a blog so that we can continue to bring you interesting, informative, and timely postings related to our mission. This year, 2017, will see 110 years since the founding of the CGS.

The first RockTalk appeared in 1998 and was followed by forty seasonal issues until the most recent one in 2011. We constantly get requests for back issues and to continue publishing, so in accordance with the times, we decided to make the shift to digital media. We hope you will join us by subscribing (to receive an email when we make a new posting, please enter your email in the subscription box in the right-hand column).

Content-wise, we’ll be exploring all of the many aspects of our State Survey mission to:

  • Help reduce the impact of geologic hazards on the citizens of Colorado
  • Promote responsible economic development of mineral and energy resources
  • Provide geologic insight into water resources
  • Provide geologic advice and information to a variety of constituencies

And, along the way, we’ll also post pertinent information on general geology, geoscience research and education, science and engineering policy, and other items that cross our screens. If you have any questions or suggestions, please get in touch!

Mar 142017
 

We just found out about this year’s Cumbres & Toltec Geology Train adventure in southwest Colorado/northwest New Mexico — 18 June 2017. It’s a special opportunity to enjoy some of that Rio Grande Rift, Brazos Uplift, Tusas Mountains, San Luis Basin, and San Juan Sag scenery.

Our very own Peter Barkmann, geologist extraordinaire and veteran Geology Train guide, will be on board for an informative and energized day in the high country.

On June 18th, a special train will depart to traverse spectacular geology along the 64 miles of Cumbres & Toltec track. But simply experiencing the incredible overviews of the Rio Grande Rift, the eruptive evidence of the San Juan Volcanic field, the Precambrian core of the Tusas Mountains, recent glacial deposits, and snapshots of the Jurassic, will not be enough. This special train will stop at many outcrops and rail cuts along the right of way, to mingle, marvel and collect photographs, samples and experiences only accessible on the train route.

ALL ABOARD!

Feb 282017
 

We have a free 8.5- x 11-inch (pdf) geologic map of Colorado containing Geo-Whizology of Colorado on the reverse side.

Free 8.5- x 11-inch  map of Colorado geology along with Geo-Whizology

Free 8.5- x 11-inch map of Colorado geology (front) along with Geo-Whizology (back)

Of course, we’re a bit biased, but we think Colorado has magnificent geology and it is beautifully displayed for all to see. The state holds many of the biggest, the best, the first, and the most diverse:

For instance, did you know: Continue reading »

Feb 282017
 

No Geologist worth anything is permanently bound to a desk or laboratory, but the charming notion that true science can only be based on unbiased observation of nature in the raw is mythology. Creative work, in geology and anywhere else, is interaction and synthesis: half-baked ideas from a bar room, rocks in the field, chains of thought from lonely walks, numbers squeezed from rocks in a laboratory, numbers from a calculator riveted to a desk, fancy equipment usually malfunctioning on expensive ships, cheap equipment in the human cranium, arguments before a road cut.

— Stephen Gould

Any other ideas as to where/how creative geologic ideas arrive? Any personal mythologies out there?

Feb 242017
 

One of the many fascinating videos from our geo-friends up the road at University of Colorado-Boulder.

The Interactive Geology Project was formed in 2002 by professor Paul Weimer and colleagues with the goal of producing short 3D animations about the geologic evolution of key US national parks. The first major project focused on the geology of the Colorado National Monument and is still on display in the park’s visitor center. Over time our focus shifted from national parks to animating Colorado’s geologic history, with a key goal of developing a series of 5-10 minute vignettes covering each geologic time period.

The current group of animators joined the project in the summer of 2011. In 2013 we began a major collaboration with the Denver Museum of Nature and Science to explore new ways of using 3D technology in earth science education. We work with top subject-area experts to ensure our animations are as scientifically accurate and up-to-date as possible.

Our projects are on display in museums, parks, and other venues across Colorado, the Western US, and Canada. All of our work is also available to the general public free of charge on our website and our Vimeo page.

Feb 192017
 

Diamonds are formed from pure carbon, one of the most abundant elements on planet Earth. Diamonds, even from ancient times, have been sought for their extraordinary hardness (they are the hardest substance known) and their brilliance, especially in the colorless transparent gemstone variety. Ironically the other form of pure carbon is graphite, which is very soft with a soapy feel and a dull gray color. Graphite is commonly the “lead” in a pencil.

A diamond's crystal structure: tetrahedrally bonded carbon atoms crystallized into the diamond lattice, a variation of the face-centered cubic structure.

A diamond's crystal structure: tetrahedrally bonded carbon atoms crystallized into the diamond lattice, a variation of the face-centered cubic structure.

The Mohs Hardness Scale of minerals starts at 1 (talc) and ranges to 10 (diamond). That does not mean that diamonds are ten times harder than talc; mineral number 9 on the Mohs scale is corundum, a class of minerals which includes rubies and sapphires. Diamonds can be from ten to hundreds times harder than corundum. Diamonds themselves vary in hardness; for example, stones from Australia are harder than those found in South Africa.

The four main optical characteristics of diamonds are transparency, luster, dispersion of light, and color. In its pure carbon form, diamond is completely clear and transparent. As in all natural substances, perfection is nearly impossible to find. Inclusions of other minerals and elements cause varying degrees of opacity. The surface of a diamond can be clouded by natural processes, such as the constant tumbling and scraping in the bed of a river.

Luster is the general appearance of a crystal surface in reflected light. Luster of a smooth crystal face of diamond is strong and brilliant. It is intermediate between glass and metal and has its own special term — adamantine.

Relative size of octahedral diamond crystals from 1 to 500 carats. Credit: Modified from Bauer, 1968.

Relative size of octahedral diamond crystals from 1 to 500 carats. Credit: Modified from Bauer, 1968.

The process of white light breaking up into its constituent colors is called dispersion. Diamonds have strong dispersion, which along with their strong luster, causes the beautiful play of colors so often referred to as the “fire” of a diamond.

Gemstone varieties of diamond and imperfections. Yellow or yellowish-brown and even brilliant yellow diamonds have been found. Very rarely, diamonds are blue, black, pale green, pink, violet, and even reddish.

The most famous blue diamond, the Hope Diamond, is intertwined with Colorado’s mining history. Thomas Walsh, discoverer of the rich Camp Bird Mine near Ouray, purchased the Hope Diamond for his wife in the early 1900s; it was later given to his daughter, Evelyn Walsh McLean who wore it almost continuously until the 1940s. The 45.5-carat Hope Diamond now resides at the National Museum of Natural History in Washington, D.C.

Diamonds, in their perfect cubic crystal form, occur as isolated octahedral (eight-sided) crystals. Many variations on the cubic form are found in are usually clear and colorless, often containing minor inclusions nature, including twelve-sided crystals and a flattened triangular shape known as a macle. Gemologists recognize three main varieties of diamonds: ordinary, bort, and carbonado. Ordinary diamonds occur as crystals often with rounded faces, from colorless and free from flaws (“the first water” [1]) to stones of variable color and full of flaws. Bort diamonds occur in rounded forms without a good crystal structure. They are generally of inferior quality as a gemstone. Carbonados are black opaque diamonds usually from the Bahia Province of Brazil. They are crystalline but do not possess the mineral cleavage found in ordinary diamonds.

[1] An expression which refers to the highest quality diamonds and has come to mean the highest quality of just about anything. The comparison of diamonds with water dates back to at least the early 17th century, and Shakespeare alludes to it in Pericles, 1607:

Heavenly jewels which Pericles hath lost, Begin to part their fringes of bright gold.
The diamonds of a most praisèd water Doth appear, to make the world twice rich.

Diamonds in the rough, note the regular octahedral forms and trigons (of positive and negative relief) formed by natural chemical etching.

Diamonds in the rough, note the regular octahedral forms and trigons (of positive and negative relief) formed by natural chemical etching.

Feb 172017
 
IS-79 Colorado Mineral and Energy Industry Activities 2015-16 (cover)

The current annual Colorado Mineral and Energy Industry Activities report 2015-16 is now available. Following up on the 2014 report, this report, based on 2015 production data, sketches a comprehensive overview of Colorado’s mineral resource production. Of note is the fact that total value of mineral and energy fuels production in Colorado for 2015 is estimated to be $13.43 billion, a 29% decline from the $18.8 billion production value in 2014. The decline was caused primarily by a precipitous decrease in oil and gas market prices which provide 70% of Colorado mineral resource revenue. Oil and gas production actually registered at all-time highs of 127.6 Mbbl and 1,709 Bcf, respectively.

Nonfuel mineral production — including metals, industrial minerals, and construction materials — posted a modest 3.9% increase in revenue. Increased production of crushed stone, cement, and sand and gravel aggregate accounted for the increase. With a 2015 production of 21,790 metric tons of molybdenum from two mines, Colorado is the largest molybdenum producer in the U.S. Although just one mine in the state publicly reported gold production in 2015, Colorado remains the third largest producer of the metal in the U.S. as it was in 2014.


Citation: Cappa, James A., Michael K. O’Keefe, James R. Guilinger, and Karen A. Berry. “IS-79 Colorado Mineral and Energy Industry Activities 2015-16.” Mineral and Energy Industry. Information Series. Golden, CO: Colorado Geological Survey, 2016.
Feb 172017
 

Dr. Cílek, the Director of the Czech Republic’s Academy of Sciences Institute of Geology delivers a fascinating talk about the Bohemian Karst region of the Czech Republic, around Beroun, that weaves the human historical, mystical, and mythological elements with the underlying geology and speleology.

(00:36:32, stereo audio, 70.1 mb)

Bohemian karst (Český kras) landscape formed in a limestone of Silurian and mainly Devonian age. The area hosts several international stratotype and parastratotype sections, including the main Silurian/Devonian Global Boundary Stratotype Section at Suchomasty. Photo credit: Milos Sejn.

Bohemian karst (Český kras) landscape formed in a limestone of Silurian and mainly Devonian age. The area hosts several international stratotype and parastratotype sections, including the main Silurian/Devonian Global Boundary Stratotype Section at Suchomasty. Photo credit: Milos Sejn.

Feb 062017
 

With all the precipitation in the Rockies this year (we’re at +153% normal snowpack at the moment), we thought we would re-release a publication that highlights at least one important aspect of Colorado snowfall — that is, the significant danger of avalanches. The Snowy Torrents: Avalanche Accidents in the United States 1980-86, compiled and written by Nick Logan and Dale Atkins and illustrated with Larry Scott’s fine pencil drawings, was first published in 1996. We still have a few hard-copies available and, because of that, yes, we do charge for the PDF download. However, Larry went back and re-made the PDF from the original publication file, producing a file that is far better than the rather poor digital scan we had offered previously.

The volume details 146 oft-times harrowing stories surrounding avalanches, the lives they claim, survivors and witnesses, along with assessments as to what happened, why it happened, and what could have been done to prevent loss of life and/or property. The authors are never judgmental, and their clear-eyed accounts contain a wealth of wisdom that will add to the knowledge-base of any winter backcountry enthusiast.


Citation: Logan, Nick, and Dale Atkins. SP-39 The Snowy Torrents: Avalanche Accidents in the United States, 1980–86. Special Publications 39. Denver, CO: Colorado Geological Survey, Department of Natural Resources, 1996.
Jan 312017
 

A collaboration between the CGS and the Denver Museum of Nature & Science (DMNS) has resulted in a new stratigraphic chart for the state of Colorado. This beautifully (offset-)printed 42″ x 39″ color chart was designed from the ground up to illustrate the Proterozoic to Holocene stratigraphy that spans the state’s many sedimentary basins. A collaborative effort led by Robert Raynolds and James Hagadorn, the chart builds upon the work of dozens of colleagues and updates Richard Pearl’s seminal 1974 stratigraphy chart. The chart leverages the community’s stratigraphic work in both the subsurface and outcrop, and depicts new geochronologic constraints for many units. To facilitate comparison of strata to external forcing factors, the chart employs a linear timescale. Each unit’s dominant depositional environment is depicted as are major mountain building events, erosional events, and regional unconformities. Printed on heavy-duty 100# coated cover stock, these rolled posters may be purchased from the CGS online bookstore. They will make a fine gift for geoscientists, rockhounds, or anyone interested in how Colorado’s magnificent landscapes came to be.



From the chart itself:

Colorado’s stratigraphy is dominated by gaps. The distribution of strata reflects the tectonic and climatic evolution of each of the region’s eleven basin areas, depicted in the map below. To foster comparison of these patterns, we have organized the stratigraphy using a linear timescale and illustrated where orogenic uplift has led to removal of strata or nondeposition. Not all orogenic features are illustrated on the chart. For example, some orogenies caused sediment ponding and accumulation in intermontane basins, such as during the Laramide in northwestern Colorado. In the past ~10 Ma, regional uplift has raised Colorado and has allowed the modern landscapes to be created due to erosion. The chart’s color scheme for stratigraphic units gives a sense of dominant lithologies and depositional environments across basins. Updates to this chart, as well as additional stratigraphic resources, such as stratigraphic and structural cross-sections, may be found at http://coloradostratigraphy.org. To learn more about the unit names on this chart, resources are available at the U.S. Geological Survey’s Geolex site. This chart scaffolds on the work of Richard H. Pearl’s 1977 compilation (Rocky Mountain Association of Geologists, Special Publication 2). With the exception of the Carboniferous and Permian periods, this data has been re-cast against the International Commission on Stratigraphy’s chronostratigraphic chart v. 2015/01, updated at http://stratigraphy.org.


Citation: Raynolds, R. G., and James W. Hagadorn. “MS-53 Colorado Stratigraphy Chart.” Stratigraphic. Map Series 53. Denver, CO: Colorado Geological Survey and the Denver Museum of Nature & Science, January 2017.
Jan 162017
 

On solid ground — that’s how many of us think of good old, stable earth. So it’s disconcerting when the ground moves out from under us in any way.

Because of our environment, history, and geology, Colorado has conditions where ground movements can costs millions of dollars in annual property damage from repair and remediation, litigation, required investigations, and mitigation. There has been recent attention to swelling clay soils and heaving claystone bedrock, and the media has helped publicize these problems, which are predominant along the Front Range. But that’s only half the story. Geologic hazards in Colorado also include ground that sinks. Ground subsidence and soil settlement pose significant hazards in Colorado in many areas throughout the state. A variety of causes, some human-made and others inherent to the geology and geomorphology of Colorado, cause these sinking problems. Continue reading »

Jan 112017
 

Regarding the Colorado Geological Survey (an article appearing in the Mining Reporter, March 1907):

We note that one of our contemporaries, in recently commenting on the University bill creating a State Geological Survey of Colorado — the bill reported favorably on by the joint Senate and House mining committee — voices in no uncertain language its regret at the “truly pitiable outcome of the effort to establish a Geological Survey of Colorado.” In a lengthy and well-written editorial, criticism is made of the proposed advisory board, particularly of the placing thereon of the presidents of the State University and the State Agricultural College; also, having the survey located at Boulder instead of Denver; of the naming as state geologist, the professor of geology of the State University, who may be a good teacher, but who, like the majority, may or may not be an effective executive; and lastly, of the paltry appropriation of $5,000 annually for this important work in a state productive of $50,000,000 and more yearly.

Exception is also taken to the naming of state institution teachers as assistants to the State Geologist, who ought to have the assistance of men less academic and having a knowledge of the exploitation of ore deposits and of the search for them.

This editorial expression, coming from a former Coloradoan, is worthy of consideration. It is in accord, in large part, with our own views, as our readers know. In addition to the criticisms made by our contemporary, we would like to emphasize another objectionable feature in this favorably reported bill, viz., the naming of any one as state geologist who is not to devote his entire time to the survey work. — from the Mining Reporter, vol. LV, March 28, 1907, no. 13, Denver, Colorado.

We’re happy to say that our current efforts to provide professional geologic information to the residents of Colorado far exceed the original scope of responsibilities and possibilities of the Territorial Geologist. But like those old-time miners, walking the mountains of this beautiful state, we also share a real passion for what we are doing.

You can find an in-depth history of the Survey and its 1872-legislated precursor, the office of Territorial Geologist, in IS-27 History of The Colorado Geological Survey (1872-1988), a free PDF download at our bookstore.


Citation: Rold, J. W., and S. D. Schwochow. IS-27 History of The Colorado Geological Survey (1872-1988). Information Series, IS-27. Denver, CO: Colorado Geological Survey, Department of Natural Resources, 1989.