Public Release: 

Droughts, fire, mercury, comets and more at GSA 2002

US Geological Survey

Scientists from the U.S. Geological Survey (USGS) will present new research on a variety of topics at the annual GSA meeting at the Colorado Convention Center in Denver, October 27-30. A few highlights include:

Diving the Great Blue Hole of Belize: From the air, it appears as a nearly perfect dark blue circle, fringed by a reef in a turquoise sea. Popular with divers and about 1000 feet in diameter, the Great Blue Hole of Belize has preserved thousands of years of earth's history at its 407-foot depth. In 1997, UNESCO declared it a World Heritage site. As scientists begin to analyze recently obtained sediment cores, they hope to gain insight on the frequency and intensity of Caribbean storms, and to learn more about African dust that blankets the region. "Carbonate Storm Deposits and Varve-Like Sediments within the Great Blue Hole on Lighthouse Reef Atoll, Belize, Central America," poster is scheduled for 8 a.m. - noon on Sunday, Oct. 27, Exhibit Hall.

Riding the Rockies with USGS: During the 2002 Denver Post Ride The Rockies annual bike tour, participating USGS cyclists presented a slide show explaining the geology that the ride traversed as well as USGS wildfire- and drought-related research. Understanding the geology along the route gave cyclists a better appreciation for the terrain and the work of USGS. Janet Slate will provide more details about this trek at 11:45 a.m., Sunday, Oct. 27, Room A111/109.

The Ins and Outs of Ground-Water Flow in the Southwest: Recent population growth and development in the arid Southwest have made it essential for scientists to increase their understanding of ground-water flow responses in hydrologic systems. Studying ground-water removal and alteration ground-water inflow and outflow patterns is important for the effective management of ground-water systems. The principles that ultimately dictate these patterns are simple but not well understood by many water managers and hydrologists. In the past, effects of ground-water withdrawals have been viewed mostly in terms of lowering water tables and removing water from storage. Today water-resource managers must increasingly consider how withdrawals affect the amount of water flowing in and out of aquifers. A primary concern is that ground-water withdrawals over long periods will reduce ground-water outflow, and water availability to streams, wetlands, and riparian areas. To hear more about the principles that determine the ultimate responses of inflow and outflow to ground-water withdrawals in the Southwest, attend "The Ins and Outs of Ground-Water Flow in Basins of the Southwest," from 8:35 to 8:50 a.m. on Monday Oct. 28 in Room A209.

A Sinking Feeling: What happens when agricultural and municipal-industrial demands for ground-water deplete groundwater resources? In the western United States, scientists have documented 100 meters or more of ground-water level declines, and in many places the declining trends continue at rates of 300 mm or more per year. By using satellite-borne radar (InSAR), along with other techniques, USGS scientists and their colleagues are able to detect areas that are more susceptible to aquifer-system compaction, especially in the southwestern United States. Subsidence is an ongoing concern in the San Joaquin Valley, Calif., and numerous other areas in California; the Houston-Galveston area; Las Vegas Valley, Nev., and throughout south-central Arizona. To learn more, attend "Ground-Water Depletion and Spaced-Based Monitoring of Aquifer-System Compaction in the Western USA," 8:50 a.m. to 9:05 a.m. on Monday Oct. 28 in Room A209.

Water Availability for the Western United States---the Challenge for Science: In the American West, ensuring sustainable water supplies for agriculture, industry, and municipal use without adverse effects on the environment has become a Herculean challenge. For example, the rate of U. S. population growth is the greatest in the Southwest - the most arid region of the country. Surface water is fully developed in most cases, and aquifers near population centers are already in various stages of depletion. Many communities in the Southwest are dependent on water withdrawn from ground-water storage, which cannot be sustained in the long-term. Water availability has come to mean water for endangered flora and fauna, in addition to the traditional off-stream uses such as municipal supplies and irrigation. A key challenge for science in this new era will be to quantify the physical habitat requirements of individual species of concern. To hear more about the use of scientific information in the development and management of western water supplies, attend "Science to Support the Management of Western Water," from 9:05 a.m. to 9:20 a.m., Monday Oct. 28 in Room A209.

Skeletons from Seawater: The dawn of the Cambrian, more than half a billion years ago, was a time of unprecedented change on Earth. A major pulse of calcium entered the global ocean from the spreading seafloor below, and an explosion of life followed. It included a diversity of species, individuals that were larger than anything before, and some of the first complex skeletons. Were these events related? "Did Changes in Seawater Chemistry Play a Role in the Cambrian Explosion?" is scheduled for 10:30 am on Monday, Oct. 28, Room A102/104/106.

Impacts of Abandoned Mercury Mines: Conversion of relatively stable inorganic mercury compounds to bioavailable organic mercury forms, such as methylmercury, is a potential hazard around abandoned mercury mines in the U.S. and worldwide. Elevated concentrations of methylmercury is highly toxic to humans. The USGS is working with university and industry mercury researchers to evaluate mercury speciation and biochemical transformation to toxic mercury compounds at several abandoned mercury mines in the U.S. This presentation will focus on mercury mines in semiarid regions, such as Terlingua, Texas, and McDermitt, Nev., with reference to other mercury mines worldwide. Learn more by attending John Gray's presentation, "Mercury Speciation and Transformation in Mine Wastes Collected from Abandoned Mercury Mines in the U.S." on Tuesday, Oct. 27 at 10:40 a.m. in Ballroom 4.

How Does Fire Really Impact the Landscape? The recent occurrence of catastrophic wildfires throughout the world, coupled with the continued encroachment of human development into fire-prone ecosystems, has resulted in the need for a better understanding of how fire affects the hydrological and depositional responses of watersheds. The talks and posters presented will cover such diverse topics as the controls on post-wildfire runoff, effects of fire on soil, the effectiveness of post-fire rehabilitation efforts, post-wildfire hazard assessments, and the development of new tools and methodologies for assessing post-wildfire runoff and erosion. In the GSA Topical Session "Geomorphic Impacts of Wildfire", scheduled for Tuesday, Oct. 29 and Wednesday Oct. 30, studies of post-wildfire response that provide the basis for better methods for predicting the form and magnitude of post-wildfire runoff processes, as well understanding of the role of wildfire in shaping the landscape, will be presented by various scientists, Room C209 and Exhibit Hall.

Worldly Discovery Made in Denver Suburb: The discovery and collection of petrified, juniper-like, logs in Highlands Ranch, Colo., by USGS scientist Tom Michalski and high-school student Andrew Lieberman of Denver, gave science a special opportunity for study -- 50-million-year-old pieces of rare fossil wood containing resin or amber inside. Only a half dozen other identifiable fossil wood specimens containing resins have been reported in the entire world, making this more unique than meteorite or dinosaur finds. These one-of-a-kind results will be shared at the Geological Society of America annual meeting on Oct. 30 during the Paleontology/Paleobotany Poster Session in the Exhibit Hall at 8 a.m.

New Piece of Alamo Impact Puzzle Revealed: A unique spindle-shaped bomb, ejected from the crater of the 370-million-year-old Alamo Impact in southern Nevada, has been discovered in deep-water deposits farther west in Nevada by Charles A. Sandberg, USGS Geologist Emeritus and Jared Morrow, USGS volunteer and Associate Professor at the University of Northern Colorado. This discovery proves that the Alamo Breccia, produced by a cometary impact into the Late Devonian sea that covered North America for tens of million years, is far more extensive than originally documented. Their new findings will be presented at Session #239 in the Exhibit Hall at 1:30 p.m.

What Lurks Beneath Yellowstone Lake? High-resolution mapping of the floor of Yellowstone Lake, the largest high-altitude water body in North America, indicates that rhyolitic lava flows are responsible for the control and distribution of hydrothermal activity in the lake. Through this mapping, USGS scientists, led by Lisa Morgan, have identified several previously unknown features in the lake, including over 250 hydrothermal vents, several large hydrothermal explosion craters, many small hydrothermal vent craters, an extensive fault system, and landslide deposits that constitute potentially significant geologic hazards. Details about how the team acquired these findings and what the research means will be presented on Wednesday, Oct. 30 at 4 p.m. in Room C102/104/106.

Huge Outburst in Alaska: On Aug. 14, at about 3 a.m., water trapped in a 70-square-mile lake by Alaska's Hubbard Glacier was released into the ocean in a spectacular torrent. This glacial outburst flood was the second largest in historical times. For eight hours straight, it released at least 1.5 million cubic feet of water per second. After 33 hours of discharge, the lake's surface had dropped to sea level from a peak of nearly 50 feet above. Learn the complete story of the formation of Russell Lake and the flood that returned it to a fiord. "The 2002 Closure of Russell Fiord, Alaska - June & July 2002," is scheduled for 11:45 a.m. on Wednesday, Oct. 30, Room C209.

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The USGS, a bureau within the Department of the Interior, serves the nation by providing reliable scientific information to describe and understand the Earth; minimize the loss of life and property from natural disasters; manage water, biological, energy and mineral resources; and enhance and protect our quality of life.

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