January 2001 – Emmons Lecture
“SNOWBALL EARTH AND EARLY ANIMAL EVOLUTION”
Department of Earth and Planetary Sciences, Harvard University
Many lines of evidence support a theory that the entire Earth was covered by ice for long periods 600-700 million years ago. Each glacial period lasted for millions of years and ended violently under extreme greenhouse conditions. These climate shocks apparently fostered the explosive radiation of multicellular animal life, and challenge long-held assumptions concerning the limits of global change. Ironically, both the theoretical basis for a ‘snowball’ Earth and the geological evidence of its occurrence were developed independently in the 1960s, but the confluence of theory and observations was long delayed.
To view the entire paper and illustrations on The Snowball Earth, see:
KON-TIKI REVISITED:OBSERVATIONS OF A GEOLOGIST
It has been several decades since Thor Heyerdahl wrote Kon-Tiki, dramatizing his theo- ries on the connection between the Inca of South America and the early inhabitants of Easter Island. Certainly, these two populations shared a strong affinity for geology and working with rock. The Inca constructed elegant stone structures and produced more than enough food to feed their population with the assistance of sophisticated irrigation projects. The Rapa Nui, residents of Easter Island, carved magnificent statues of impressive size that were moved across the island to stand as sentries staring for hundreds of years across the ocean.
As a youth, I remember visiting friends of my parents where a coffee table book of mysterious places provided my entertainment while the adults talked.There were two photos in that book that captured my imagination completely, Machu Picchu and the staring statues on Easter Island. I decided then that I would have to see these places myself. In travel log style, we will explore these almost mystical places, through the camera and observations of an inquisitive geologist. As to an answer for the question of whether or not residents of Easter Island were early tourists from South America, I will let you decide.
GEOLOGIC,HYDROLOGIC,AND GEOCHEMICAL PROCESSES CONTROLLING THE FORMATION AND WEATHERING OF MINERAL DEPOSITS – EXAMPLES AT A VARIETY OF SPATIAL SCALES
U.S. Geological Survey
Although studies of environmental issues abound in the recent literature,no set protocol exists for designing and executing an environmental study that is truly representative of any particular natural system. For example, few, if any, studies consider the scale dependence (spatial or temporal) of natural or man-made processes acting in a system,and design sampling and analytical strategies to represent those scale dependencies. This, despite the fact that nearly every “environmental ” study implicitly comprises some spatial and temporal properties. Mineral deposits provide convenient objects of study for a variety of reasons:they represent a “point source ” of constituents in ground and surface water ((usually metals and sulfate)that may be traced through the environment; most of them document the existence of paleo-hydrologic systems, many of which are hydraulically conductive today;they occur in spatially limited bodies of rock,allowing for a convenient spatial scale for study; they occur in a variety of climatic and hydrologic settings around the world. Examples of spatial scales of natural mineral- forming and-weathering processes ranging from millimeters to kilometers will be presented, with discussions of the appropriate types of data needed to characterize such processes.
AEROGEOPHYSICAL MEASUREMENTS OF COLLAPSE-PRONE HYDROTHERMALLY ALTERED ZONES AT MOUNT RANIER VOLCANO
Dr. Carol Finn
U.S. Geological Survey
Hydrothermally altered rocks can weaken volcanoes, increasing the potential for catastrophic sector collapses that can lead to far-travelling, destructive debris flows.Evaluating hazards due to alteration is uncertain because alteration has been mapped on few active volcanoes and because the distribution and severity of subsurface alteration is largely unknown on any active volcano.At Mount Rainier (Washington State, USA), collapses of hydrothermally altered edifice flanks have generated numerous far-travelled debris flows and future collapses would threaten now densely populated areas.
Preliminary geologic mapping and remote sensing indicate that exposed alteration is contained in a dike-controlled east-west belt passing through the summit. However,new helicopter-borne electromagnetic and magnetic data, combined with detailed geologic mapping, reveal that appreciable thicknesses of mostly buried altered rock lie mainly in the upper west flank of Mount Rainier,identifying this as the most likely source for future large debris flows. Negligible highly altered rock lies in the volcano’s core, which may impede collapse retrogression and limit volumes and inundation areas of future debris flows. High- resolution geophysical and geologic observations yield an unprecedented view of the 3-D distribution of collapse-prone altered rock, and the approach has potential application to hazardous volcanoes world-wide.
SCIENCE IN THE INTERNATIONAL HOT SEAT: ASSESSING MINING-RELATED ENVIRONMENTAL ISSUES ON MARINDUQUE ISLAND, THE PHILIPPINES
U.S. Geological Survey
This talk will summarize a May,2000,USGS-Armed Forces Institute of Pathology trip to examine the environmental impacts of recent large-scale,open-pit mining on Marinduque Island,Philippines, including the Marcopper Mine (operated from 1969-1996), and the CMI Mine (operated in the 1970’s). Substantial further work is clearly needed to fully assess the extent of the mining-environmental problems and impacts of mining relative to pre-mining environmental conditions,and to develop scientifically strong remediation strategies.
The USGS-AFIP Marinduque visit underscored the need for impartial integrated science when assessing the environmental and health impacts of large-scale metal mining near the ocean.However, the visit also under- scored the substantial political and cultural challenges faced by scientists who undertake such assessments.
The speaker acknowledges the great contributions of the other scientists who participated in the Marinduque trip,including:Bob Morton (coastal processes, USGS), Terry Boyle (aquatic ecotoxicology, USGS), Jack Medlin (USGS International Group), and José Centeno (human toxicology, Armed Forces Institute of Pathology). The contributions of Scott Carr (marine toxicology, USGS), who visited Marinduque in October, 2000, and collected data on the aquatic toxicology of tailings in the near-shore marine environment, are also gratefully acknowledged. A digital version of the group’s trip report is available at:
AN EXCURSION TO THE KARAKORAM RANGE IN NORTHERN PAKISTAN
Russell F. Dubiel
U.S. Geological Survey
In 1997 Russ and four friends trekked in the Karakoram Range of Baltistan in northern Pakistan to visit climbers from Colorado who were attempting to climb Gasherbrum II, one of the world’s fourteen 8000 meter peaks. On the way, they passed five of those 8000 meter peaks, including K2, second in height only to Mt. Everest in the Himalayas. The trip covered 28 days, over 200 miles of hiking, and traversed a 20,000 ft pass. The Karakoram Range contains the greatest concentration of high peaks in the world, along with spectacular examples of alluvial fans, braided rivers, and glacial geology. Russ will present an overview of the trip, general geology, and the intriguing Muslim culture.
DUST–PAST, PRESENT, AND FUTURE
U.S. Geological Survey
Each year, about 2 billion metric tons of eolian dust (windblown silt and clay) are transported in the atmosphere, mainly from sources in east central Asia and the Sahel-Sahara region of Africa. Today’s dust, however, pales in comparison to the amount of atmospheric dust during the Last Glacial Maximum. How much dust will be generated in the future, and why do we care?
Dust in Quaternary geologic deposits such as loess, deep-sea sediments, and ice provides outstanding records of climatic change that enable comparisons of climatic signals among terrestrial, marine, polar, and high-altitude settings. Dust even affects climate–it may warm or cool the surface depending on various factors. For this reason, atmospheric general circulation models to simulate past and future climates are being improved by incorporating estimates of dust flux and sources based on geologic and ice-core studies.
Dust emissions today from the world’s arid regions affect human health, damage equipment and infrastructure, impede transportation, diminish air quality, and play important roles in ecosystem health and dynamics. The largest dust plumes cross oceans. North America commonly receives African dust in the Caribbean basin and along the southeastern states, while the Pacific Northwest sometimes receives Asian dust typically mixed with industrial pollutants. Although minor on a global scale, dust emissions from our southwestern deserts produce many of the same effects regionally and locally as do larger dust storms elsewhere. New methods to detect southwestern dust emissions, track transport paths, and identify eolian dust in soils are leading to a detailed picture of dust flux over time and its critical role in the evolution of the Colorado Plateau ecosystem, where far-traveled dust provides essential plant nutrients. Related field and modeling studies are underway to enable forecasts of southwestern dust emissions under future climates.
RISK IN AMERICA: A HISTORICAL PERSPECTIVE, AND CHALLENGES FOR THE PUBLIC EARTH SCIENTIST
U.S. Geological Survey
Pioneer literature and diaries are rife with examples of the kind of uncertainty and risk that were commonly accepted as part of everyday life a little over a century ago. We read these accounts and experience vicariously the sense of high adventure that accompanied the happenings of daily life in the American West. Similarly, the “western” movie genre is readily recognized as an idealized sense of the American experience. As a society, however, we lately have lost this acceptance of the inherent uncer-tainty of life and have moved toward the current situation where “zero risk” is desired in most aspects of our lives. We wish to be protected from the vicissitudes of nature. We want to be assured of “zero casu-alties” before we endorse declarations of war.
How does the public earth scientist respond to the current “risk averse” culture that we find ourselves in? Earth scientists are often more aware of the limits to their data and interpretations than potential users of the information. Our new understandings of complexity and interdependence give us a greater sense of humility as scientists, even as models get more “precise”. To secure public funding for our scientific research in the face of increased societal expectations, we are tempted to promise the outcome that the public seems to want from us-elimination of risk. Is it reasonable to make these assurances, or is it a potential set-up for failure and disappointment when the public discovers that we may not be able to live up to such promises? Is it in our purview as public earth scientists to help the public understand the limitations of science, or will that only encourage a decrease in funding, thus eliminating our chances to gain scientific understandings that would help us to at least mitigate against certain outcomes? Some would argue that this is the greatest challenge facing the earth scientist today as we are increasingly engaged in the public policy arena.
NATIONAL SEISMIC HAZARD MAPS
Charles S. Mueller
U.S. Geological Survey
The U.S. Geological Survey has recently completed new seismic hazard maps of the United States. The maps depict probabilistic ground motions that are of interest to structural engineers: peak ground acceleration and spectral ground motion at periods of 0.2, 0.3, and 1.0 second for 10%, 5%, and 2% probabilities of exceedence in 50 years. Innovations in methodology include the direct use of histori-cal seismicity (counted on a grid and smoothed), inclusion of more than 450 specific faults with geologi-cally determined slip rates, and use of background zones based on broad geologic criteria to account for hazard in areas with seismic potential but little historic activity. Alternative models of seismic activity and ground-motion attenuation are accounted for in a logic-tree formalism. Engineering-design maps derived from the ground-motion maps are included in the 1997 National Earthquake Hazards Reduction Program Recommended Provisions for Seismic Regulations for New Buildings and underpin the year 2000 International Building Code.
“WATER, WATER, EVERYWHERE, NOR ANY DROP TO DRINK”: POSSIBILITIES FOR MICROBIAL LIFE ON A GAS PLANET
Colorado School of Mines
Liquid water has long been assumed to be an absolute requirement for the sustenance of life, primarily because of its excellent solvent properties. Intracellular water stabilizes and mobilizes cytoplasmic macromolecules, while extracellular water facilitates the transport of nutrients and wastes to and from cell surfaces and stabilizes the very cell envelopes themselves. Indeed, no life on Earth, in all its astonishing variety, has adapted to an environment devoid of liquid water.
Nevertheless, the role of water, and liquid water in particular, in sustaining life deserves closer examination. Consideration of the vast array of Earthly microorganisms that inhabit extreme environments, including salt-saturated brines, Antarctic ice sheets, dark hydrothermal vent fluids reaching temperatures of 150ºC, and volcanic lava deficient in water as well as soluble nutrients, reveals that microorganisms have evolved elegant mechanisms to ameliorate the problems posed by external dryness. Evaluation of these mechanisms allows the apparent requirement for external liquid water to be understood more specifically as an intracellular requirement for certain chemical attributes of water, described by the idea of water potential, rather than a requirement for the liquid phase itself. Alternative environments that might lack a liquid phase, but provide water with properties essential for life, will be considered.
A second aspect of the apparent requirement for liquid water is the need for a fluid to dissolve and circulate essential nutrients among cellular life forms. Such circulation is necessary both for the needs of individual organisms and for the continual elemental recycling that enables entire ecosystems to function. Because many Earthly nutrients are bioavailable primarily as water-soluble molecules, liquid water has seemed essential in this role as well. Again, however, examination of known microbial communities calls this apparent requirement into question. Many resourceful microbes have developed ways, even here on Earth, to obtain energy, “fix” carbon to build cellular machinery, and dispose of waste products entirely in the gaseous phase. Consideration of these mechanisms, and the possibilities for development of ecological systems using these mechanisms exclusively, will conclude the discussion.
“THE EFFECTS OF N2O ON THE EARTH’S ENVIRONMENT”
Department of Chemistry and Geochemistry, Colorado School of Mines
The effects of N2O on global greenhouse warming, stratospheric ozone destruction, soil N2O emissions, will be discussed as well as and a case study on N2O emssions from lanfdills. The talk will also include some of our preliminary data on isotope measurements of N2O emissions from Colorado Grassland. soils.
“AVALANCHES AND THEIR IMPACT ON PEOPLE AND INDUSTRIES”
Colorado Avalanche Information Center
A multimedia presentation will present an introduction of snow and avalanches with an overview of the avalanche problem in Colorado and the United States as it relates to recreation,transportation,mining,and land-use issues.Avalanches will be described as to their awesome power and destructive forces and strategies for mitigating avalanche hazards discussed.
Dale Atkins has been an avalanche forecaster with the Colorado Avalanche Infor- mation Center since 1987 and a professional ski patroller involved in mountain rescue for more than 25 years.Dale is the U.S.representative to the Avalanche Commission in the International Commission for Alpine Rescue and has published numerous articles and videos on avalanches.
“SHEEP MOUNTAIN:BACK-LIMB TIGHTENING AND SEQUENTIAL DEFORMATION IN A CLASSIC LOCALITY IN THE BIGHORN BASIN, WYOMING”
Colorado State University
“PROXIMAL-DISTAL RELATIONSHIPS OF DEEP-WATER DEPOSITS, PERMIAN BRUSHY CANYON FORMATION, WEST TEXAS”
Brian W. Romans
Colorado School of Mines
“GAS CLOUD KILLS THOUSANDS AT LAKE NYOS, AFRICA: IDENTIFYING THE CULPRIT AND SAVING LIVES IN THE FUTURE”
Michele L. W. Tuttle
U.S. Geological Survey, CSS President
In 1986, Lake Nyos, Cameroon released a cloud of CO2 that kill 1700 people and devastated domestic herds and wildlife for many kilometers. Was this the work of lake spirits or a geological phenomenon previously unrecognized? This talk takes us on a tour of the mysteries surrounding Lake Nyos immediately following the disaster and shows how data collected over the next decade identified the culprit and the mitigation strategies to save lives.