Previous editions of newsletter, and PDF versions.
Changes in loess and dune deposition in response to Quaternary climatic fluctuations, Columbia Plateau, Pacific Northwest
The paired dune-loess eolian system of the Colorado Plateau in Washington state allows the study of dynamic interactions of dune and loess systems. Eolian facies of the region lie in the arid to semi-arid rain shadow of the Cascade volcanic range, and prevailing winds that transport sediments move southwest to the northeast. Eolian sediments have been obtained since at least the late Quaternary and perhaps much earlier from fine-grained slackwater deposits (produced by glacial outburst flooding) exposed in upwind basins. Loess deposition appears to span much of the Quaternary.
Eolian dunes and other sandy eolian deposits lie on the upwind perimeter of the Palouse loess. Three mechanisms appear to control the thickness of loess on the plateau. 1) Topographic traps: Deeply incised valleys effectively separate saltation from suspension processes by sequestering sand that allows the deposition of the suspension load as thick loess on the downwind sides of valleys.
2) Shifts in bioclimate: In the absence of topographic traps, the sand-silt boundary freely transgresses and regresses as a function of climate shifts that control soil moisture and vegetation cover density. Over time, the eolian sand has become interstratified at the margins of deflating basins in response to these climate shifts. The mid- Holocene was dominated by dune activity (lesser vegetative cover and drier surface soils leading to more aggressive saltation processes); the present is dominated by loess deposition. Greater vegetative cover and/or moister soils shift saltation processes to a more arid upwind position, with suspension fall of dust accumulating loess on the flat.
3) Source sediment texture: Source sediment texture controls the balance of dunes versus loess accumulated downwind of specific basins. An “ideal” source sediment is dominated by sand, which limits aggregation and crusting and provides abundant, mobile sand for saltation, while also having significant (20–40%) silt and clay to provide a source of fine dust that is ejected during saltation and forms loess downwind by suspension fall. A source sediment rich in sand but poor in silt results in thin loess.
These three sets of controls appear to have operated separately and in combination to create measured variations in loess thickness. Insight into how saltation and suspension processes interact with each other to control sedimentology and geomorphology of this paired eolian system is key to better understanding the eolian environment of the Columbia Plateau and other eolian systems.
Mars rover results, liquid water, and the potential for life on Mars
The Mars Opportunity rover has returned spectacular results suggesting that there was a substantial body of water at the Meridiani landing site. I'll discuss these results in the context of the history of liquid water at the surface and in the subsurface, and then I’ll turn to the implications for climate and for the potential that life might have existed or might still exist on Mars. I'll also discuss the Mars exploration program as it is planned out over the next decade and the implications of President Bush's recently announced new vision for exploration by NASA.
For those of us in academics, May is the major transition of the year. Classes end, finals are given, and students leave the universities and colleges. For me it is the start of a several-month field season. As a consultant geologist (my other profession), my field projects include short, small projects and the continuation of research projects have taken years to develop. Geology is great because you can look at a small area and learn much (if you only look hard enough) or you can work for years on a project and still learn something new. Sometimes its takes months of work over many years to get an understanding of a geologic system. For example, it took colleagues, students, and me seven years of field work to recognize and map the 26 widespread marker beds in the middle Eocene Bridger Formation of the southern Green River Basin. However, this work provides only the framework for much more detailed studies on fluvial architecture, basin analysis, lacustrine sedimentology, biostratigraphy, and paleoenvironmental studies that will require decades of work to complete.
I feel fortunate to work on long-term field projects. Few professional geologists now have this luxury. Long-term field projects are almost impossible to get funded, so professional geologists typically go into the field for only a week or two— which allows only very rudimentary (at best) or superficial (at worst) analyses. Many-year field projects are still required for much graduate-student research. I have many times heard a colleague say, when an important field problem comes up, “I’ll send a student to work on it.” This is sometimes the worst thing to do since many projects require study by researchers who have a great knowledge of the subject, not someone just developing their ideas and techniques. Besides, I am always amazed at what one learns by studying geology in the field, and even the most experienced geologists will continue to learn if they keep their eyes and mind open. There are no simple solutions to the dearth of longterm geologic research projects, but it is a problem that should be acknowledged.
We had a great family night. More than 50 people showed up at the Fiske Planetarium to hear Joe Romig and Glen Porzak chat about climbing the eight highest peaks in the solar system. Thanks to Joe, Glen, Tito Salas (director of the Planetarium), and all those who came to the talk!
Have a great summer and (I hope) a great field season!
CSS Memorial Fund awards for 2004
The CSS Memorial Fund Committee (Jim Cappa, Eric Nelson, Bruce Bryant, Greg Holden, and Don Sweetkind) met on April 28, 2004 to evaluate proposals for the Tweto, Oriel, Eckel, Snyder, and Pierce Heart Mountain funds. We received 24 proposals (five fewer than last year) from 18 universities throughout the United States.
Twelve awards totaling $9,425 were made from the five funds. $2,800 total, which supported three proposals, was awarded from the Tweto Fund for research in the Rocky Mountains. The Oriel Fund for research in the central and northern Rocky Mountains awarded $2,000 total to three proposals. The Eckel Fund for research in engineering geology awarded $625 to support one partial proposal. The Snyder Fund for research on Precambrian geology of the Rocky Mountains awarded $1,000 to one proposals. A total of $3,000 was awarded from the Pierce Heart Mountain Fund, under new guidelines established by the Pierce family last year, for research on the Heart Mountain fault and in areas not covered well by the other funds. This year a proposal for work on the Heart Mountain fault and three other proposals were funded.
During the past 21 years (including this year), the Society has helped support the graduate research of 165 students, awarding a total of $125,657 (an average of nearly $750 per grant). This achievement is extraordinary for an organization of our size and exemplifies the commitment of its members to promote high-quality research in the earth sciences. It was an honor and pleasure to serve as Memorial Fund Chair this year and I want to extend a “thank you” to all the Memorial Fund donors that have made these grants possible. The 2004 recipients of CSS memorial funds awards are as follows:
Three one-day field trips are currently scheduled for this summer: geology of I-70 across the Front Range on May 30, geology of the Pawnee Buttes area on June 19, and Precambrian geology of the east-central Front Range on August 14. Each will be a preview trip for the GSA Annual Meeting in November; the previews will be during (presumed) excellent weather and will be much less expensive (participants will provide their own lunches).
Sunday, May 30—Colorado Front Range—Anatomy of a Laramide uplift. Leaders: Karl Kellogg, Bruce Bryant, and Jack Reed. Registration deadline: May 21. Cost: $25. Transportation: Vans only. Departure: 8:00 am, Cold Spring Park and Ride (6th Avenue and Union). The trip will travel along I-70 to the Silverthorne area to examine the geology along a cross section through the Front Range. Karl, Bruce, and Jack have decades of experience working on geology of the Front Range, so this trip is a must for those who are interested in our local geology. Since the trip will be stopping at narrow exits along I-70, we will travel in vans and personal cars are discouraged. Please note: the date of this trip differs from the date given in previous announcements.
Saturday, June 19— Cenozoic geology and fossils of the Pawnee Buttes area, northeast Colorado. Leader: Emmett Evanoff. Registration deadline: June 11. Cost: $8. Transportation: Car pools. Departure: 8:00 am, RTD Park and Ride at 1st Avenue and Strong Streets in Brighton, Colorado. We will visit many of the fossil vertebrate sites that paleontologists have studied for the past 130 years. The geology of northeast Colorado is subtle but fascinating.
To find the Brighton Park and Ride from Denver, go north on I-76 to US 85. Go north on US 85 toward Brighton, and turn to the east (right) onto Bridge Street (Colo 7). If you are coming from the north, come down US 85 (the Greeley Highway) to Bridge Street, and turn east (left) and cross the highway bridge. Follow the signs to the RTD Park and Ride, that will be on the left side of Bridge Street between 1st Avenue and Main Street, north of the Brighton Chamber of Commerce. Because of the driving distance, we will probably not return to Brighton until about 6 PM.
Saturday, August 14—Continental accretion–Colorado style: Proterozoic island arcs and back arcs of the central Front Range. Leaders: Lisa Lytle and Thomas Fisher. Registration deadline: August 6. Cost: $8. Transportation: high-clearance 4-wheel-drive vehicles are needed for car-pools (please volunteer yours!). Departure: 8:00 am, Cold Spring Park and Ride, 6th Avenue and Union. We will examine the Precambrian features of the Front Range northwest of Golden. We received a preview of this trip during the April field trip, but Lisa and Thom will take us to many additional sites.
|
Registration Form—Summer 2004 Colorado Scientific Society Field Trips
|
||||||||||||||||
|
||||||||||||||||
| (make check to Colorado Scientific Society) TOTAL AMOUNT ENCLOSED |
The 2004 Fall Field Trip will take us to the Black Hills and Badlands National Park in South Dakota. Leaders: Jack Redden, John Lufkin, Lee Shropshire, and Emmett Evanoff. Dates: Thursday through Sunday, September 23–26. Cost: $300 (includes transportation, lodging, and lunches).
DAY 1: Drive to Custer; stop at the Hot Springs Mammoth Site. This excellent local museum displays bones of dozens of mammoths in an ancient sinkhole deposit that acted as a natural trap. DAY 2: Examine the Precambrian and Paleozoic rocks of the Black Hills under the guidance of Jack Redden, a retired USGS geologist who mapped and subdivided the Precambrian rocks of the Black Hills. We hope to visit some of the famous pegmatite mines and end up in Rapid City in the evening. DAY 3: We will examine the geology and fossils of Badlands National Park; Emmett will discus the stratigraphy and origin of the most fossiliferous parts of the White River Group. DAY 4: Drive to Devils Tower and then return to Denver. Lee Shropshire, UNC, will lead this last day. Buy dinners and breakfasts in Custer and Rapid City throughout the trip.
You will receive additional information concerning the trip in September.
|
Registration Form—Fall 2004 CSS Field Trip to the Black Hills and Badlands
|
||||||||
|
||||||||
| (make check to Colorado Scientific Society) TOTAL AMOUNT ENCLOSED |
Wow! Check out those gasoline prices! Fuel is still cheaper than a gallon of milk, but it just seems un-American to pay more than a buck-eighty for Texas Tea. You oil patchers must be jumping for joy, or do higher prices only translate to bigger bonuses for the CEOs? The other day I read we (pessimistically) have 35 years of oil left. My first question is, “Who's ‘we,’ tar man?” When the supply gets low I don't imagine the great unwashed will be receiving its share. Git thee to a hybrid car! Anyone know of an alternative fuel that will run our jumbo jets and spy planes? Do we have tanks and humvees that run on Everclear? According to the History Channel, even nuclear-powered aircraft carriers use gazillions of gallons of fuel. I wonder if the Hawks flitting around Washington know that. Hey, I've got an idea: maybe if we explain to them that without petroleum products they won't be able to put on a decent war, they'll start backing alternative energy! Woo-hoo!
Colorado Scientific Society's regular meetings are held the third Thursday of the month (unless otherwise advertised). Social time begins at 6:30 p.m. and presentations start at 7:00 p.m. For info., contact Jim Cappa at (303) 866-3393, jim.cappa@state.co.us.
Denver Mining Club meets every Monday (except when noted) at Country Buffet near Bowles and Wadsworth (at 8100 W. Crestline Ave.) 11:30 a.m.-1:00 p.m. For additional information contact Dick Beach, (303) 986-6535. See past and future DMC talks at the web site: http://www.china-resources.net/.
Denver International Petroleum Society meets the 2nd Friday of each month at the Wynkoop Brewing Co., 18th and Wynkoop Streets. Reception begins at 11:30 a.m., luncheon at 12 p.m., program at 12:30 p.m. Make reservations (required) by leaving message at (303) 623-5396. Reservations accepted after 8 a.m. on Friday until 10:30 a.m. on Wednesday prior to the meeting. Cancellations accepted until 11:00 am Wednesday prior to the meeting. Cost: $15 for lunches; talk only is available for $2 (make checks payable to "D.I.P.S."). Keith Murray at (303) 986-8554 for information.
Denver Region Exploration Geologists' Society (DREGS) meets in the Mutual Consolidated Water Building, 12700 West 27th Avenue, Lakewood. Social hour 6:00-7:00 p.m. Technical presentation at 7:00 p.m. Meetings are normally scheduled for the first Monday of each month. For information contact Jim Piper, (303) 932-0134, or the website http://www.dregs.org/.
Denver Well Logging Society (DWLS) meets on the third Tuesday of each month, Sept. through May. Lunch and a technical talk at the Wynkoop Brewery begins at 11:30 a.m., 18th and Wynkoop Sts. in Denver. Subject matter usually deals with the application of well logs to oil and gas exploration. Call Elice Wickham at 303-573-2781 for reservations. Web page: http://dwls.spwla.org/.
Rocky Mountain Association of Geologists (RMAG) Reception at 11:30 a.m., lunch at 12:00 p.m., talk at 12:30 p.m. Reservations are taken by recording at 303-623-5396 until 10:30 a.m., Wed. before the luncheon. Cancellations are taken until 11:00 a.m. on Wed. at 303-573-8621. Luncheon cost is $20 payable to RMAG at the door. Reservations are not required for talk only---cost is $3. Meeting location: Denver Petroleum Club, Anaconda Tower, 555-17th St, 37th floor.
Friends of Dinosaur Ridge and the Morrison Natural History Museum 7:00 pm at Red Rocks Elementary School in Morrison, CO. Join now. Web page: http://www.dinoridge.org/.
University of Colorado at Boulder, Geological Sciences Colloquium Wednesdays, 4:00-5:30 p.m., Rm. 180. Refreshments at 3:30 p.m on the 3rd floor. For info., call 303-492-8141. Web page: http://www.colorado.edu/GeolSci/. Colorado School of Mines Van Tuyl Lectures Fridays 3:00 p.m. to 4:00 p.m. in Berthoud Hall, room 108. Web page: http://www.mines.edu/academic/geology/calendar/vantuyl.html
For a constantly updated, online geo-calendar, visit the Colorado Geological Survey at: