GSA TODAY • Mapping Program, P

Vol. 7, No. 8 August 1997 INSIDE GSA TODAY • Mapping Program, p. 11 • Hazardous Waste, p. 18 A Publication of the Geological Society of America • Penrose Conference Report, p. 19

The Edwards Aquifer: A Resource in Conflict John M. Sharp, Jr., Jay L. Banner, Department of Geological Sciences, University of Texas, Austin, TX 78712-1101

Figure 1. Space shuttle photograph of central Texas showing prominent physiographic features (see also Figs. 2, 3, and 5) that dic- tate patterns of recharge and flow in the Edwards aquifer. The land- scape break shown by the color change across a southwest-northeast arc from San Antonio (SA) to Austin (A) formed as a consequence of en echelon, down-to- the-southeast normal faults of the Balcones fault zone. Urbanization of land (indicated by the light gray colors) around Austin, San Anto- nio, and the area in between has increased rapidly in the previous decade. North is to the top of the photograph. Austin–San Antonio distance is 120 km. Shuttle photo #NASA STS-62-97-143 (March 1994). Inset: The Barton Springs swimming pool in Austin, Texas, exemplifies the conflicting interests regarding the aquifer’s waters. The pool is supplied by springs that discharge from submerged orifices in fractured limestone, which is visible on the right bank. The pool and surrounding park are important recreational resources. This spring system is the sole environment for the rare Barton Springs salamander, which is a federally listed endangered species. The rising skyline of the City of Austin is visible in the background. Water demands and conflicts will increase with increasing urbanization.

ABSTRACT INTRODUCTION The Edwards aquifer of central Texas is an extensive, karstified flow system There is a saying in Texas—“whiskey developed in rocks deposited on a Cretaceous limestone platform. Development of is for drinking, water is for fighting.” the aquifer was controlled by changes in sea level, large-scale hydrodynamic and Fighting over water resources involves tectonic processes in the Gulf of Mexico, and local climatic and geomorphic pro- legal, political, and economic interests. cesses. The aquifer is a vital water resource and provides a diverse set of habitats, Much attention is focused on the Edwards including those for several endangered species that live in its major spring systems. aquifer, which is one of the most prolific Because of its unique stratigraphic, hydraulic, and hydrochemical properties, the aquifers in North America, providing Edwards aquifer is a natural laboratory that is well suited for hydrogeologic studies. water for more than two million people. Because of numerous economic, social, and political interests in the use of the It provides all the water used by the City water and because of the rapid rate of population growth (and urbanization) of its of San Antonio and by numerous smaller watersheds, the aquifer is also a source of political conflict. Competing interests for municipalities, industry, and agriculture. its waters have stimulated an ongoing debate over how the aquifer would best be Individual well yields can be tremendous; utilized. Historical water-balance analysis demonstrates that major water shortages a City of San Antonio well drilled in 1941 will develop with the recurrence of historic decadal droughts. Future decisions had a natural flow of 16,800 gallons/minute regarding the aquifer’s use will therefore have significant socioeconomic and envi- (1.06 m3/s; Livingston, 1942), and a well ronmental ramifications. These decisions should be based upon accurate hydrogeo- drilled in 1991 is reportedly the world’s logical data. The general nature of how the aquifer functions is understood, but greatest flowing well, with a natural more detailed interpretations are needed. Application of ground-water flow models discharge of 25,000 gallons/minute based on field data and natural geochemical tracers have the potential to reduce uncertainties in the details of how the aquifer functions now and will function in response to potential future developments. Edwards Aquifer continued on p. 2 IN THIS ISSUE GSA TODAY August Vol. 7, No. 8 1997 The Edwards Aquifer: SAGE Remarks ...... 14 A Resource in Conflict ...... 1 Educom Medal Award ...... 15 GSA TODAY (ISSN 1052-5173) is published monthly by The Geological Society of America, Inc., In Memoriam ...... 2 GSAF Update ...... 16 with offices at 3300 Penrose Place, Boulder, Colorado. Notice of Council Meeting ...... 2 Mailing address: P.O. Box 9140, Boulder, CO 80301- About People ...... 17 9140, U.S.A. Periodicals postage paid at Boulder, Col- Legislative Alert ...... 3 Environment Matters ...... 18 orado, and at additional mailing offices. Postmaster: Send address changes to GSA Today, Membership Ser- GSA on the Web ...... 9 Penrose Conference Report ...... 19 vices, P.O. Box 9140, Boulder, CO 80301-9140. Penrose Conferences Scheduled: August Bulletin and Geology Contents .... 27 Copyright © 1997, The Geological Society of America, Crustal Differentiation ...... 10 Inc. (GSA). All rights reserved. Copyright not claimed on Ocean Island Volcanoes ...... 26 GSA Annual Meetings ...... 28 content prepared wholly by U.S. Government employees within the scope of their employment. Permission is EDMAP Program ...... 11 GSA Section Meetings ...... 29 granted to individuals to photocopy freely all items other Calendar ...... 30 than the science articles to further science and educa- Washington Report ...... 12 tion. Individual scientists are hereby granted permission, Classifieds ...... 31 without royalties or further requests, to make unlimited Letter to the Editor ...... 13 photocopies of the science articles for use in classrooms to further education and science, and to make up to five copies for distribution to associates in the furtherance of science; permission is granted to make more than five photocopies for other noncommercial, nonprofit pur- In Memoriam poses furthering science and education upon payment of the appropriate fee ($0.25 per page) directly to the Copyright Clearance Center, 222 Rosewood Drive, George M. Brown Nikolaus H. Heine Dorothy Lewis Danvers, Massachusetts 01923, phone (508) 750-8400 Oxford, England Germany Queensland, Australia (when paying, reference GSA Today, ISSN 1052-5173). March 27, 1997 June 24, 1997 April 23, 1997 Written permission is required from GSA for all other forms of capture, reproduction, and/or distribution of Joseph R. Chelikowsky Ralph H. Howe Henry G. Thode any item in this publication by any means. GSA provides this and other forums for the presentation of diverse Manhattan, Kansas Bluff, Utah Hamilton, Ontario opinions and positions by scientists worldwide, regard- March 31, 1997 June 1997 June 1997 less of their race, citizenship, gender, religion, or political viewpoint. Opinions presented in this publication do not reflect official positions of the Society.

SUBSCRIPTIONS for 1997 calendar year: Society Members: GSA Today is provided as part of member- Notice of Council Meeting ship dues. Contact Membership Services at (800) 472-1988 or (303) 447-2020 for membership informa- Meetings of the GSA Council are open to Fellows, Members, and Associates of the Soci- tion. Nonmembers & Institutions: Free with paid ety, who may attend as observers, except during executive sessions. Only councilors, subscription to both GSA Bulletin and Geology, other- officers, and section representatives may speak to agenda items, except by invitation of wise $50 for U.S., Canada, and Mexico; $60 elsewhere. Contact Subscription Services. Single copies may be the chair. Because of space and seating limitations, notification of attendance must be requested from Publication Sales. Also available on an received by the Executive Director prior to the meeting. The next meeting of the Coun- annual CD-ROM, (with GSA Bulletin, Geology, GSA Data cil will be Tuesday afternoon, October 21, 1997, at the Annual Meeting in Salt Lake City. Repository, and an Electronic Retrospective Index to journal articles from 1972). Members order from Member- ship Services; others contact subscriptions coordinator. Claims: For nonreceipt or for damaged copies, members contact Membership Services; all others contact Edwards Aquifer continued from p. 1 decisions will have to be made about these Subscription Services. Claims are honored for one year; water resources in the coming decades. please allow sufficient delivery time for overseas copies, 3 up to six months. (1.58 m /s; Swanson, 1991). The Edwards These decisions should be based more on aquifer also provides important recre- accurate scientific data and less on politi- STAFF: Prepared from contributions from the ational resources in stream waters and cal exigencies. Hydrogeological facts about GSA staff and membership. in the parks that surround major spring the Edwards aquifer and related natural Executive Director: Donald M. Davidson, Jr. Science Editors: Suzanne M. Kay, Department of Geo- orifices that discharge the aquifer’s water. (including biological) resources must be logical Sciences, Cornell University, Ithaca, NY 14853; The streams that flow over the aquifer and effectively conveyed to those drafting Molly F. Miller, Department of Geology, Box 117-B, are fed by its springs provide needed fresh policy and making decisions about future Vanderbilt University, Nashville, TN 37235 Forum Editor: Bruce F. Molnia water to the south Texas Gulf Coast bays resource utilization. U.S. Geological Survey, MS 917, National Center, and estuaries, which are the nurseries for The Cretaceous rocks that form Reston, VA 20192 shrimp, redfish, and other species of the aquifer are present over much of Managing Editor: Faith Rogers Production & Marketing Manager: James R. Clark coastal and marine wildlife. Texas, either in outcrop or in the subsur- Production Editor and Coordinator: Joan E. Manly The aquifer has been the subject of face. These units also extend into northern Graphics Production: Joan E. Manly, Leatha L. Flowers recent litigation, notably regarding the Mexico (Lesser and Lesser, 1988). There maintenance of natural flow to certain are three aquifers in these rocks (Fig. 2): ADVERTISING: Classifieds and display: contact Ann Crawford (303) 447-2020; fax 303-447-1133; spring systems and the preservation of the the Edwards-Trinity (Plateau) aquifer, the [email protected] threatened and endangered species that Edwards (Washita Prairie) aquifer, and the Issues of this publication are available as electronic dwell in them. This conflict has developed Edwards (Balcones fault zone) aquifer. Acrobat files for free download from GSA’s Web Site. because the communities and region that The last is the most prolific and is what They can be viewed and printed on various personal overlie and rely upon the Edwards consti- most people consider the Edwards aquifer computer operating systems: MSDOS, MSWindows, Macintosh, and Unix, using the appropriate Acrobat tute one of the fastest growing urban cor- (and that to which we refer in this paper). reader. The readers are widely available, free, including ridors in the United States (Fig. 1). During It stretches in a band (usually <64 km from GSA at: http://www.geosociety.org/pubs/index.htm. 1996, undeveloped land in Williamson wide) from the Rio Grande river near This publication is included on GSA’s annual CD-ROM, County, north of Austin, was being subdi- Del Rio east through San Antonio, then GSA Journals on Compact Disc. Call GSA Publication Sales for details. vided for homes and businesses at the northeast through Austin, and ends near rate of one acre every three hours (Austin- Printed in U.S.A., using pure soy inks and recyclable American Statesman, 1996). Significant paper. Edwards Aquifer continued on p. 3

2 GSA TODAY, August 1997 Legislative Alert: House Moves To Eliminate Tax Exemption for Graduate Student Tuition Waivers

The U.S. House of Representatives recently passed H.R. 2014, member organization dedicated to the pursuit of world class sci- which modifies the federal tax code. One provision of this bill entific knowledge about the Earth, I am acutely aware of the chal- would eliminate the current tax exemption for graduate students lenge that we face in striving to maintain the preeminent status who receive tuition waivers from their universities. If this provi- of the nation’s research effort. The key element to meeting this sion becomes law, graduate teaching and research assistants challenge is the quality of our next generation of scientists. Abil- would have to pay taxes on the value of their tuition waivers, ity in science—not ability to pay—must remain the prime crite- starting with 20% of the waivers’ value in 1998, and rising incre- rion for entry into our graduate programs. Elimination of the mentally to 100% in 2002. The tuition waivers, in other words, tuition waiver exclusion could seriously compromise our capacity would be treated as taxable income. to fulfill this criterion. Senate tax legislation, S. 949, does not eliminate the tuition In considering this issue, I urge you to keep in mind some waiver exemption. This and other differences between House- very special aspects of our graduate science education system. and Senate-passed tax bills must be ironed out in a conference Graduate education in science is a process that requires deep per- committee meeting. For updated information on the status of the sonal commitment over many years of hard work and meager tax legislation, visit the American Geological Institute’s Web site: pay. Our best graduate students typically receive stipends of less www.agiweb.org and click on “Government Affairs.” than $15,000, and they are often in their late twenties or early In response to passage of H.R. 2014, GSA President George A. thirties when they complete their studies. If these students must Thompson has written the following letter to House Ways and accept an additional tax burden on tuition waivers—which may Means Committee Chairman William Archer: be worth as much as $20,000 per year—the economics of graduate training in science may become untenable for those without The Honorable William Archer, independent financial means. This is particularly the case because Chairman, Committee on Ways and Means, the salaries that scientists receive after finishing graduate school United States House of Representatives, Washington, DC 20515 are far less than those for graduates of law, business, and medical Dear Chairman Archer: schools. While a future doctor, lawyer, or corporate executive can For the past 50 years, the U.S. Congress has been a steadfast justify the high cost of professional training based on anticipated supporter of the nation’s system of scientific research and educa- future earnings, scientists do not have this luxury. Thus, if we ask tion. This system is the envy of the world, and the source of the our graduate students to accept a considerable real increase in tax talent and innovation that will fuel our nation’s welfare in the burden (and, in many cases, an increase in personal debt, as coming century. Congress is to be commended for maintaining well), we may well find that our most promising future scientists its historical commitment to research and education even while opt for more economically viable careers in the professions. struggling to get the nation’s fiscal house in order. In this light, In the coming century, every aspect of the nation’s well I want to point out that recent provisions of House-passed tax being—from economic competitiveness in the global market- reform legislation, H.R. 2014, threaten to undermine this com- place, to the preservation of health in an aging population, to the mitment and our investment in training the nation’s next gener- development of energy resources and protection of the environ- ation of scientists and engineers. In specific, the provision that ment—will depend on the ability and ingenuity of our scientists. would eliminate Section 117(d) of the tax code—the exclusion of Short-term revenue losses resulting from the tax exclusion for tui- tuition waivers or reductions from taxable gross income—could tion waivers will be paid back in spades by the long-term benefits have a serious negative impact on the nation’s ability to attract of our investment in the next generation of world class scientists. the best and brightest students into our graduate science pro- Sincerely, grams. I write to strongly urge that Section 117(d) be restored George A. Thompson, President to the final tax bill during House-Senate conference. [Geological Society of America] As President of the Geological Society of America, a 15,000

Edwards Aquifer continued from p. 2 known, but the lack of knowledge about STRATIGRAPHY AND STRUCTURE many details disturbs those who need to The aquifer is in carbonate rocks the town of Salado in Bell County. The make decisions and wish to maintain a that were deposited in shallow subtidal boundaries of the Edwards aquifer (Fig. 3) broad consensus of support. As stated by to tidal-flat facies on an extensive marine are (1) the northern and western limits Tilford (1994), “geological facts and fan- platform approximately 100 m.y. ago. This of the outcrops (except in the west, where tasies will be called on to support both stratigraphic package formed as part of an it is continuous with the Edwards-Trinity proponents and critics” of any water extensive series of shallow-water carbon- Plateau aquifer; (2) the Rio Grande; and resources project, and “unknowns are ate-evaporite platforms that encircled the (3) the bad-water line, which separates powerful tools,” whether or not war- margin of the ancestral Gulf of Mexico the fresh-water zone (potable waters) ranted, in the hands of these groups. during a major marine transgression in the from the bad-water zone (brackish or In this paper, we review the hydrogeology Early Cretaceous. Subsequent lowering of saline waters with >1000 mg/l total dis- of the aquifer (its stratigraphy, structure, sea level, rapid burial of the deep sections solved solids). Of particular interest is the and relatively unique hydraulic parame- of the Gulf of Mexico basin, tectonic uplift aquifer between the ground-water divides ters) and major issues facing the many along the margins, and erosion and karsti- near Brackettville (east of Del Rio) and users of the aquifer, and we suggest some fication have played important roles in Kyle (just north of San Marcos) because areas where hydrogeological research the development of the aquifer (see Fig. 4 this is the largest segment of the aquifer should have both practical and scientific for representative stratigraphic sections). and includes San Antonio. implications. Detailed hydrostratigraphic relationships There have been many studies of the Edwards aquifer. The aquifer’s water balance and how it functions are basically Edwards Aquifer continued on p. 4

GSA TODAY, August 1997 3 porosity, permeability, and water chemistry and (2) make the Edwards one of the most highly productive aquifers in North Amer- ica. Even though the aquifer is commonly treated as a single hydrostratigraphic unit, its properties are highly variable both later- ally and vertically. This variability, coupled with the intricacies and variability created by karstification, leads to considerable Figure 2. Edwards complexity within the aquifer. aquifers of Texas. HYDROGEOLOGY

The Edwards aquifer receives approxi- Edwards Plateau Aquifer mately 80% of its recharge through losing Edwards Aquifer (Washita Prairies) (influent) streams that flow over its un- N confined parts. Most of the remaining Edwards Aquifer 0 30 mi recharge is from direct precipitation on Bad-water line aquifer outcrops. Minor amounts of 0 50 km Oil fields in Edwards recharge come from the movement of saline ground waters across the bad-water line, from leaky water mains and sewage lines in urbanized areas, and from cross- Edwards Aquifer continued from p. 3 normal to the strike of the aquifer. The formational flow from underlying units. early Miocene, en echelon normal faults A cross-formational flow component is are given in Rose (1972), Maclay and of the Balcones fault zone dip toward the locally important especially to the north, Small (1986), and Pavlicek et al. (1987), Gulf of Mexico. Throws vary, reaching a where the aquifer thins, and it may be among many others. maximum total displacement of >500 m identified by chemical and isotopic signa- Some confusion still persists over along the San Marcos Arch (Fig. 5). The tures (Clement and Sharp, 1988; Oetting differences between hydrostratigraphic result is a series of blocks of Edwards et al., 1996). Recharge from streams is and stratigraphic nomenclature. It is aquifer rocks that are partly to completely highly variable because it depends primar- not always recognized, for instance, that offset. Some of these blocks are uncon- ily upon the duration and intensity of although the Edwards aquifer is present in fined and some are confined. The San stream flows. Figure 6 shows historical the San Antonio area, the Edwards Lime- Marcos Arch has been a persistent high trends in recharge to and discharge from stone is not! The Edwards aquifer is a during the late Mesozoic and Cenozoic, the aquifer. Average recharge over the hydrostratigraphic unit that generally and the carbonates that lie above it are period of record has been 682,800 acre- includes all rocks above the Glen Rose more highly dolomitized. Finally, the feet/year (26.63 m3/s), but the highest Limestone and beneath the Del Rio Clay, aquifer has been affected by several uplifts. recorded recharge was 2,486,000 acre- except where the latter has been eroded The first, in the Cretaceous, resulted in feet/year (96.95 m3/s) in 1992, and the and aquifer crops out. The aquifer thick- karstification before deposition of the lowest recorded was 43,700 (1.70 m3/s) ens to the south and southwest from Georgetown Formation (Fig. 4); this was in 1956 (Edwards Underground Water about 60 to 275 m. followed by several episodes of erosion District, 1993). Discharge is by springs and Both the upper and lower confining and karstification. The major uplift, in the wells, and well discharge has increased in units are continuous and widespread. early Miocene, led to both major faulting the 60 years of record to meet the growing In the Glen Rose, layers of limestone and and modern karstification. needs of the population and irrigation. marl alternate and form a local aquifer The stratigraphic and structural fea- Well discharge is inversely correlated with with a low vertical permeability. The Del tures serve to (1) control the distribution of years of high recharge (and precipitation). Rio Clay is a very efficient confining layer. recharge features, primary and secondary It consists of low-permeability smectitic shales with occasional shell-fragment beds. Where exposed at the surface, the Del Rio Clay is a gray, sticky, expansive clay and is Bell well known for causing foundation and Figure 3. Hydraulic 1200 Equipotentials (100 ft above sea level) slope-stability problems. The geologic for- boundaries, locations Down-dip limit of recharge zone of major springs, and mations of the aquifer (Fig. 4) have highly Bad-water line 600 typical equipotential Major Springs Williamson variable hydrogeologic properties. Organic, map of the Edwards Ground-water divides reeflike buildups of an unusual suborder of aquifer (modified from 800 bivalves called rudistids are common in Sharp, 1990). Travis the aquifer unit. These provide significant Barton Springs primary porosity. The Regional Dense (Austin) N Member of the Person Formation is rela- Hays 800 tively unkarstified and functions as a semi- Kyle divide 0 30 mi confining unit. The Leached and Collapsed 600 Comal 0 30 km San Marcos members of the Person Formation and the Springs Kirschberg Evaporite Member of the Kainer Bexar Val Verde Comal Springs Formations tend to be the most permeable Kinney Uvalde Medina (New Braunfels) units because of secondary permeability 700 1200 1100 800 San Antonio and caused by dissolution. 900 San Pedro Springs 1000 The structure is simple regionally, but 1000 San Felipe it can be quite complex locally. Subdued Springs Brackettville (Del Rio) divide arches and synclines are oriented nearly

4 GSA TODAY, August 1997 the different members within the aquifer SW REGIONAL PROVINCES NE and variation in the throw of faults. Devils River San Marcos San Marcos Maverick Basin Reef Trend Platform (West) Platform (East) The faults may serve as barriers to flow between blocks and simultaneously serve DEL RIO CLAY as conduits to flow along the fracture GEORGETOWN Figure 4. Strati- planes. Only guesses can be made regard- graphic formations FM. ing the detailed hydraulic characteristics that make up SALMON PEAK the Edwards–Balcones of the fracture systems. There are exten- FM. Cyclic DEVILS Marine fault zone aquifer. sive cave systems that support a strikingly RIVER Leached Member names diverse subsurface ecosystem that includes LS. Collapsed are shown for the two species of blind catfish (Longley,

McKNIGHT Person Fm. Regional Dense EDWARDS Person and Kainer 1981). Flow-system delineation by tracer FM. WEST Grainstone FM. Formations. NUECES Kirschberg Evap. tests demonstrated complexities unusual FM. Dolomite even in karst systems (N. Hauwert, 1996,

Basal EDWARDS GROUP personal commun.). Consequently, even Basal Nodular WALNUT FM. Transgressive Unit though several numerical models have Kainer Fm. GLEN ROSE LIMESTONE been developed, they only simulate the general characteristics of the system. It is often proposed at public hearings that the aquifer can be overdrafted during drought Nevertheless, the current needs of the discharge to wells or at the large springs. because large recharge events will replen- regions that depend upon the aquifer These include San Pedro and San Antonio ish the aquifer. This would avoid both the exceed the historical water availability springs in San Antonio, Comal Springs costs of a huge regional water distribution during the drought of 1947–1956. When and Hueco Springs, near New Braunfels, system and use restrictions, and would a similar decadal drought occurs, it will be and San Marcos Springs in San Marcos. allow the current users of the aquifer to a considerable hardship to the region. In In the confined part of the Edwards, the continue to use this very high quality, order to plan for the combination of an flow is nearly parallel to the strike of the cheaply produced water for current and extended period of low recharge with the aquifer. San Marcos Springs is the lowest projected needs. However, this scenario is rapid urbanization of the area, authorities natural discharge point of the aquifer (570 rendered tenuous by unknown potential must consider use restrictions and water- ft/174 m above mean sea level). Just north effects of severe overdrafting on water supply plans, as discussed below, and ways of San Marcos, a ground-water divide near quality, water availability, and habitats to raise revenue to institute them, includ- Kyle separates the San Antonio system of (especially those of endangered species ing (unpopular) higher water rates or the aquifer from the Barton Springs sys- living in the two largest spring systems). (equally unpopular) higher taxes. tem, which ultimately discharges to the The general flow systems are under- Colorado River in Austin. GEOCHEMISTRY: BAD WATER, stood, but local hydrogeological details are Maclay and Small (1986) and Maclay FRESH WATER, AND EFFECTS complex. Faulting and subsequent dissolu- and Land (1988) recognized several OF URBANIZATION tion along fractures create a very heteroge- domains of highly variable transmissivity. neous and anisotropic permeability distri- Faulting has juxtaposed different hydro- Major and trace element concentra- bution. The orientation of the maximum stratigraphic units in the aquifer, so that tions and isotopic variations in Edwards permeability is subparallel to the strike of some fault blocks are almost isolated. ground waters provide clues to the sources the rocks and fracture trends. All waters Other blocks are connected, to varying of dissolved ions in the waters and the recharged east of the ground-water divide degrees, with the adjacent ones, because near Brackettville flow east, where they of the variable hydraulic characteristics of Edwards Aquifer continued on p. 6

45 Balcones fault zone Luling fault zone N 40 Devils River Uplift 35 Llano Uplift 30 RS Round Rock Syncline Recharge BH Belton High 25 SA San Marcos Arch BH 20

15 RS Cubic meters/second 10 Spring 5 Pumpage flow

SA 0 38 42 46 50 54 58 62 66 70 74 78 82 86 90 Year 0 30 mi Figure 6. Water budget for the San Antonio part of the Edwards aquifer. 0 50 km Five-year linearly weighted averages of recharge and discharge from wells and springs (data from Edwards Underground Water Conservation Figure 5. Structural trends in the Edwards aquifer (modified from Sharp, District, 1992, written commun.). Note: 1,000 acre feet per year = 1.38 1990). cfs = 0.039 m3/s.

GSA TODAY, August 1997 5 Edwards Aquifer continued from p. 5 Figure 7. Strontium isotope variations in the Edwards aquifer system. processes that govern the chemical evolu- All 87Sr/86Sr values are for tion of the waters. As demonstrated by waters and rocks from the Sharp and Clement (1988), the bad-water Edwards, except for those line marks the convergence of two flow of the Trinity Group bad systems (Fig. 3). The first is characterized waters, which are from by very high permeabilities and flow rates underlying stratigraphic units. Low 87Sr/86Sr values and by low-salinity, oxidizing Ca-HCO3 of aquifer carbonate and waters. The second flow system is rela- evaporite rocks reflect their tively stagnant and is characterized by Lower Cretaceous marine higher salinity, reducing waters of several origin. Major ion composi- hydrochemical facies. Consequently, this tions are used to define six chemical boundary (the bad-water line) Edwards bad-water hydrochemical facies, A through also reflects a physical change in the E', that are also geographi- hydrogeological regime. Downdip from cally distinct, as repre- the aquifer toward the Gulf of Mexico, sented by distance along Edwards aquifer–equivalent rocks are a southwest-northeast tran- important oil reservoirs. Natural oil seeps sect along the bad-water line from Kinney to Bell occur in outcrops of aquifer rocks along County. These bad waters the Balcones fault zone. Hydrocarbons change in the southwest- and associated oil-field brines influence northeast sequence: facies bad-water zone chemistry in the central (A) Ca-SO4 waters; (B) part of the Edwards aquifer. Integrated Ca-Mg-SO4 (low Na-Cl); Sr isotopic and major and trace element (C) Ca-Mg-SO4 (high Na-Cl); (D) Na-Cl; (E) Na-SO -Cl; variations indicate that a wide range of 4 (E') Na-Cl-SO4-HCO3. The processes are involved in the origin and geochemistry of Edwards evolution of different bad-water hydro- bad waters portray regional chemical facies in the Edwards (Fig. 7; controls on ground-water Clement and Sharp, 1988; Oetting et al., evolution, as discussed in the text. Only Edwards bad-water samples are referenced to the ordinate. 1996). These processes include (1) incon- Although fresh waters in the Edwards aquifer (ground water, surface water, and precipitation) have a wide range in 87Sr/86Sr similar to bad waters and brines, fresh-water isotopic variations appear to reflect gruent dissolution of gypsum, (2) recrys- more local controls such as flow paths and residence time in the aquifer. Data are from Oetting (1995), tallization of calcite, (3) ion exchange Oetting et al. (1996), and sources cited by them. with clays, (4) sulfate reduction, (5) fluid mixing involving at least five end-member ground-water compositions, and (6) interaction with igneous intrusions. Regional nio, where fresh ground water is with- studies of the effects of development on and local variations in hydrogeologic drawn from wells near the bad-water line. water quality in the Edwards will need to parameters that may govern the extent In contrast to the regional bad-water constrain natural compositional variability to which these processes occur include the compositional patterns, geochemical and and flow paths (using tracers), as well as mineralogy and thickness of the aquifer, Sr isotope variability in the fresh-water changes in land use and impervious sur- the extent of flow along fractures, and aquifer appears to be a function of varia- face coverage. The amount and distribu- the composition of saline ground waters tions in smaller scale factors such as flow tion of impervious cover are key measures in Edwards rocks downdip and in under- routes and ground-water residence times for assessing and predicting the effects of lying hydrostratigraphic units. in the karst aquifer, soil type and thick- urbanization on water quality in water- Strontium isotope values in Edwards ness, and land use (e.g., Banner et al., sheds in Austin and other metropolitan aquifer bad waters vary regionally, from 1996). Studies of local fresh-water flow areas (Veenhius and Slade, 1990; Schueler, lower values in the southwest part of the systems within the Edwards, such as the 1994). aquifer, where it is relatively thick and Barton Springs segment in the Austin area On the basis of regional geochemical evaporite-rich, to higher values in the (Fig. 3), indicate that ground water and studies, it is clear that more focused stud- northeast, where the aquifer is thinner surface water in some parts of the aquifer ies of surface water and ground water and evaporite-poor. This can be accounted contain higher than normal concentra- within individual watersheds in the for by the enhanced effect of mineral- tions of sediment, hydrocarbons, pesti- Edwards aquifer will improve our under- solution reactions between bad-water and cides, bacteria, nitrate, and heavy metals. standing of the sources and transmission host-aquifer minerals in the southwest The spatial distribution of elevated con- of water, sediment, and dissolved material aquifer region (i.e., facies A in Fig. 7) and taminant levels in ground water relative through the aquifer. Mineralogical and the increased mixing of saline waters from to land use indicate some correspondence chemical studies of sediment sampled downdip Edwards units and underlying between contamination and those parts of from recharge and discharge sites and hydrostratigraphic units in the northeast- the aquifer where urban development has from within the aquifer demonstrate the ern part of the aquifer (i.e., facies E and been heaviest (Slade et al., 1986; Veenhius potential for allochthonous sediments to E'). The geochemical and isotopic signa- and Slade, 1990; Hauwert and Vickers, introduce and transport surface contami- tures of bad waters may be useful in moni- 1994). This correspondence is enhanced in nants into the aquifer (Mahler and Lynch, toring the encroachment and source of surface waters during periods of increased 1996). Integration of hydrogeological, Edwards brines or cross-formational flow runoff and flow resulting from storms geochemical, and biological studies may from underlying hydrostratigraphic units (Veenhius and Slade, 1990). Conflicting reveal critical habitat controls, such as into the aquifer in response to drought interests regarding the development of solute sources, on biota that occupy sur- or increased pumpage. The saline water the aquifer’s watersheds has led to intense face and ground-water ecosystems (e.g., encroachment problem is particularly per- scrutiny of the scientific methods used in Carney et al., 1996). Geochemical and tinent in densely populated areas that rely such water-quality studies (see Addendum geochronological studies of calcite solely on the Edwards, such as San Anto- to Hauwert and Vickers, 1994). Future deposits in Edwards caves can provide

6 GSA TODAY, August 1997 insight about the relation between climate and its population is smaller than that of (2) decreasing water demands, or (3) better variability and ground-water flow and the San Marcos salamander. Protection management and more efficient use of composition on a range of temporal scales of endangered species requires protection existing resources. How much water is (e.g., Banner et al., 1996). of the spring system environments against stored in, discharges from, and recharges contamination and loss of flow—a diffi- the aquifer is generally known, as is how ENDANGERED SPECIES cult task in a region of increasing urban- the water is being used (53% municipal, ization. 36% agricultural, 3% industrial, 8% rural A significant drop in natural (spring) domestic and livestock; Technical Advi- discharge occurred during the period from LEGAL-POLITICAL-ECONOMIC sory Panel, 1990). Potential management 1947 to 1956 (see Fig. 6). The two largest MANAGEMENT PROBLEMS actions will benefit from a better under- spring systems are Comal and San Marcos standing of the hydrogeology of the springs. Comal Springs ceased flow for Texas has an intriguing system of Edwards aquifer. If the detailed hydrogeol- more than four months in 1956, and water law. Surface waters are owned and ogy were better understood, for instance, San Marcos Springs discharge dropped allocated by the state. Any extraction of then we should be better able to: (1) target to about 50 cubic feet per second (cfs) water from a stream or its underflow well-field locations to maximize produc- (1.42 m3/s). Since then, several organisms (Meinzer, 1923; Larkin and Sharp, 1992), tion and minimize adverse effects; living in these springs have been listed except for domestic or livestock use, must (2) manage well production with respect under the Endangered Species Act of 1973. be approved by the state. On the other to which river basin is contributing At San Marcos Springs, these are (1) the hand, ground water belongs to the land recharge; (3) evaluate more precisely San Marcos salamander (Eurycea nana), owner who can produce it by the “rule methods of spring-flow augmentation (2), a fish, the fountain darter (Etheostoma of capture.” The owners of the land above which could be used to maintain minimal fonticola), and (3) the Texas wild rice the Edwards aquifer consequently have flows during drought; (4) predict more (Zizania texana). A fourth species, the San a legal right to pump as much water as accurately how waste water recovery (and Marcos gambusia (Gambusia georgei) has they can as long as they use it beneficially, injection?) systems will function in the not been observed for several years. This don’t use it in a malicious manner, or neg- aquifer; and (5) predict more accurately fish may be extinct, but it is still listed. ligently cause subsidence. However, con- the effects of urban development, con- At Comal Springs, fountain darters had tinued pumping during times of drought struction, and point-source pollution. In been present before 1956, but they could will reduce spring flows and violate the particular, as the watersheds in the urban not be found in 1974 (Schenck, 1975). Endangered Species Act. In addition, the areas increase the amount of impervious Fountain darters from San Marcos Springs communities of New Braunfels and San cover and sewage lines (which inevitably were reintroduced to the Comal Springs Marcos gain considerable revenues from leak), what will be the eventual effects on system between February 1975 and March the recreational users of the Comal and water quality? 1976 (U.S. Fish and Wildlife Service, San Marcos rivers, which are fed almost 1984). There is now a significant popula- solely by the springs. The Edwards Aquifer PROMISING RESEARCH tion of the darters at Comal Springs Authority was created by the Texas legisla- (Crowe and Sharp, 1997). Several other ture in January 1993, to regulate with- Analysis of the Edwards aquifer situa- species at Comal Springs may be candi- drawals in order to protect spring flows tion suggests that detailed hydrogeological dates for listing as endangered species. and thereby protect the endangered studies could have significant economic These include the Comal Springs salaman- species of Comal and San Marcos springs. applications as well as providing new der (Eurycea sp.) and the Comal Springs However, resolutions to the conflicts are insights into the processes that form the riffle beetle (Heterelnis comalensis). not cheap, readily available, or agreeable aquifer, the processes now occurring in A lawsuit was filed in 1991 by the to all parties. the aquifer, and how to develop more Sierra Club against the U.S. Fish and First, population growth is intensify- meaningful numerical simulations. Wildlife Service and other agencies in ing water demands. Second, there are no Detailed precise answers are sought by order to maintain adequate spring flows potential alternative water resources that the various groups contesting uses of the for the preservation of these species. This can provide high-quality, abundant water Edwards waters, but our hydrogeological has resulted in the establishment of mini- as cheaply as the Edwards aquifer. Third, and hydrostratigraphic knowledge is of a mum springs flows required for the preser- there are few, if any, sites for potential regional and conceptual nature. Signifi- vation of the species. These minima are high-yield reservoirs in the area, and cant financial decisions will be based upon 100 cfs (2.83 m3/s) at San Marcos Springs downstream users of streamflow, such our current knowledge, or lack thereof. and 200 cfs (5.66 m3/s) at Comal Springs. as the city of Corpus Christi, object to The scientific questions include: What are The latter limit may be reduced to 150 cfs actions that will diminish the flows that the details of the aquifer’s hydrogeologic (4.25 m3/s) if the ramshorn snail, an intro- replenish their reservoirs. In addition, property distribution?; What is the extent duced tropical species, can be controlled. some levels of fresh-water flow to the of flow between various fault blocks?; Can This snail is a voracious herbivore and can coast are required to maintain the eco- we predict travel paths and times within significantly alter the ecosystem of the logical health of the estuaries of the south the aquifer?; and What flow equations Comal Springs system. A review of these Texas Gulf Coast. The state of Texas and are suitable? For instance, is Darcy’s Law requirements can be found in McKinney the users of the Edwards aquifer waters applicable, or is the flow better described and Sharp (1995). Historical data, how- are not immune to the financial conse- by turbulent flow models? Can we ever, clearly demonstrate that spring flows quences of who will be allocated or sup- quantify with any reasonable degree of in the Edwards (not just at these two plied with water. Coupling these consider- certainty how siting of the pumping wells largest springs) cannot be maintained ations with the complexities of interbasin would affect spring flows? under the drought conditions similar to or interstate regional water transfer makes Uncertainties exist in the analysis those of the mid-1940s to mid-1950s, even clear the difficulties associated with future for methods of springflow augmentation if the demand for water was still that low. water-resource development in this area, and artificial recharge. Artificial recharge The Barton Springs salamander even though it overlies one of the most structures have been proposed, and some (Eurycea sosorum) was recently listed by prolific aquifers in the world. have been constructed with some success the federal government as an endangered Solutions to all water shortages in- (HDR, 1993). Not all sites or areas are species. This salamander has been found volve one or more of the following types only in Barton Springs in Austin (Fig. 1), of actions: (1) increasing water supplies, Edwards Aquifer continued on p. 8

GSA TODAY, August 1997 7 Edwards Aquifer continued from p. 7 extreme position is that even if all dis- and the aquifer will be stressed. A greater charge from the springs were diverted, understanding of the aquifer’s and the equally conducive, because the permeabil- there would be very little effect on fresh region’s hydrogeology is required to use ities and the connections between various water reaching the Gulf Coast. Water these precious water resources more effi- faulted blocks are irregular. What are the balance studies should be conducted to ciently in response to the changing com- best mechanisms and where are the best analyze these possibilities. bination of demands and constraints. sites for enhanced or artificial recharge? Scientific analyses are needed for Uliana and Sharp (1996) and McKinney the evaluation of water-supply proposals, ACKNOWLEDGMENTS and Sharp (1995) examined potential which range from the simple to the We appreciate reviews by Frank methods for spring-flow augmentation. grandiose, such as a massive regional Schwartz (Ohio State University), Warren They noted that geological mapping and transfer of water from east Texas or Wood (U.S. Geological Survey, Reston), tracer tests are required near the large Louisiana to Houston, Austin, and San Greg Ellis (Edwards Aquifer Authority), springs before the feasibility of these Antonio. For instance, would the environ- Matt Uliana, Keith Young, and MaryLynn methods can be assessed with confidence. mental consequences of such a scheme be Musgrove (University of Texas), and Detailed hydrogeological mapping of the greater than those from periodic diminu- Raymond Slade (U.S. Geological Survey, aquifer has not been accomplished despite tion of spring discharges below the take Austin). Manuscript preparation costs were numerous previous studies (Menard, 1995), limit flows for endangered species? (Take supported by the Owen-Coates Fund of but recent studies by Hovorka et al. (1993, limit flows are the established minima the Geology Foundation, University of 1995), Stein and Ozuna (1995), Small et al. below which we cannot maintain the Texas, Austin. Our previous studies of (1996), and Hauwert (1997) are encourag- species’ critical habitat.) What would be the Edwards aquifer have been supported ing because they provide high quality con- the effects of such transfers on the coastal by the National Science Foundation ceptual and numerical data. Determining systems or on river systems such as the (EAR-9204980) and the Texas Water the effects of both natural processes and Sabine, the Trinity, or the Brazos? Finally, Development Board. changing land use on water quality will political and economic studies are also require studies that cover a range of spatial required. For instance, curtailment of irri- REFERENCES CITED and temporal scales. gated agriculture during droughts would Another important question requiring reduce spring-flow diminution. What Austin-American Statesman, 1996, Houses sprouting in Williamson: September 9, p. 1. quantification is the effect on the down- would be the legal, economic, social, and stream users of the proposed water hydrologic effects of such an action? Bader, R. W., Walthour, S. D., and Waugh, J. R., 1993, Edwards aquifer hydrogeologic status report for 1992: resource developments relating to the The Edwards aquifer represents an Edwards Underground Water District (now Edwards aquifer. For instance, it is commonly important natural resource where geo- Aquifer Authority) Report No. 93-05, San Antonio, assumed by the general public that all logic, hydrologic, biologic, legal, political, Texas, 71 p. the water that issues from the springs and socioeconomic factors are inter- Banner, J. L., Musgrove, M., Edwards, R. L., Asmerom, Y., and Hoff, J. A., 1996, High-resolution temporal flows into the Gulf of Mexico. The other twined. The region will be developed record of Holocene groundwater chemistry: Tracing links between climate and hydrology: Geology, v. 24, p. 1049–1052. Carney, J., Smith, A. J., and Forester, R. M., 1996, Iden- tifying modern analogs of Holocene recharge history for the Edwards aquifer, Central Texas, using ostracodes: AMQUA Proceedings with Abstracts, p. 70. Clement, T. J., and Sharp, J. M., Jr., 1988, Hydrochemi- cal facies in the bad-water zone of the Edwards aquifer, Central Texas, in Proceedings of the Ground Water Geochemistry Conference: Dublin, Ohio, National Water Well Association, p. 127–149. Crowe, J., and Sharp, J. M., Jr., 1997, Hydrogeologic delineation of habitats for endangered species: The Comal Springs/River system: Environmental Geology, v. 30, p. 17–28. Hauwert, N., and Vickers, S., 1994, Barton Springs/ Edwards aquifer hydrogeology and groundwater quality: Barton Springs/Edwards Aquifer Conservation Dis- trict, Austin, TX, Contract 93483-346 Report to Texas Water Development Board, 92 p. Hauwert, N., 1997, Geological map of the Barton Springs segment of the Edwards aquifer: Austin, Texas, Barton Springs/Edwards Aquifer Underground Water Conservation District, 1 sheet. HDR Engineering, Inc., 1993, Recharge enhancement study: Guadalupe–San Antonio River Basin: San Anto- nio, Texas, Volume 1, Executive Summary, 44 p. Hovorka, S. D., Ruppel, S. C., Dutton, A. R., and Yeh, J., 1993, Edwards aquifer storage assessment, Kinney County to Hays County, Texas: San Antonio, Texas, Edwards Aquifer Underground Water Conservation District Report No. 93-04-F0, 101 p. Hovorka, S. D., Mace, R. E., and Collins, E. W., 1995, Regional distribution of permeability in the Edwards aquifer: San Antonio, Texas, Edwards Aquifer Under- ground Water Conservation District Report No. 93- 17-F0, 128 p. Larkin, R. G., and Sharp, J. M., Jr., 1992, On the relationship between river basin geomorphology, aquifer hydraulics, and ground-water flow direction in alluvial

Edwards Aquifer continued on p. 9

8 GSA TODAY, August 1997 GSA ON THE WEB Visit the GSA Web Site at http://www.geosociety.org. From our home page you can link to many information resources. Here are some highlights:

On our Membership page you'll learn about the GSA download via your browser. These Data Repository entries Employment Service, find out how to become a GSA Campus supplement some articles in GSA’s journals. This is a new, Representative, or learn how to get forms to join GSA as a pro- faster way to obtain this data. fessional or as a student. You’ll also find information here on Every month, you’ll find tables of contents and abstracts how to nominate a GSA Member to Fellowship standing. of journal articles for GSA Bulletin and Geology, plus informa- Abstract deadline has passed. A total of 2,595 were tion for authors on preparation of articles for submission to received this year, 61% of them via our Web form. A list of all GSA. received is on the Web, under the “Meetings” heading. Watch In the Education section, read about GSA’s educational this site for acceptance and schedule information. programs, including PEP (Partners for Education Program), See the Meetings page for information on the 1997 GSA and the Earth and Space Science Technological Education Pro- Annual Meeting. Featured are: symposia and theme listings, ject (ESSTEP). Find out about GSA’s environment and public abstracts submittal information, field trips, continuing educa- policy activities in the Institute for Environmental Edu- tion courses, special programs, registration information, and cation section, including updates on the GSA Congressional travel and lodging information. Science Fellowship program, the Roy J. Shlemon Applied Under Publications, you can link to the GSA Bookstore Geology Mentor Program, and the U.S. Geological on the Web, where you can shop for any GSA book, map, or Survey–National Biological Service scientific opportunities transect in print, read descriptive copy, and order these publi- workshop. cations via our secure (encrypted) credit card ordering system. Under Foundation you will find information on the You can browse publication lists, or use our powerful search Foundation and the current annual giving campaign, a list of engine. Many items are still on sale. You’ll also find Informa- trustees and officers, and several ways to make a planned gift. tion for Contributors of journal articles, and additional infor- See the Administration section for information on GSA mation on items such as article offprints and copyright permis- Medals and Awards, research grants, and other general infor- sions. mation about GSA. You can also link to the pages for GSA Sec- The GSA Data Repository (DRP) is here, too. You’ll find all tions and Divisions for specific information on each of these. DRP entries since 1992, in Adobe Acrobat format for easy

Edwards Aquifer continued from p. 8 interaction and fluid mixing [M.A. thesis]: Austin, Stein, W. G., and Ozuna, G. B., 1995, Geologic frame- University of Texas, 204 p. work and hydrogeologic characteristics of the Edwards aquifers: Geological Society of America Bulletin, v. 104, aquifer recharge zone, Bexar County, Texas: U.S. Geo- Oetting, G. C., Banner, J. L., and Sharp, J. M., Jr., 1996, p. 1608–1620. logical Survey Water- Resources Investigations Report Geochemical evolution of saline groundwaters in the 95-4030, 8 p. Lesser, J. M., and Lesser, G., 1988, Region 9, Sierra Edwards aquifer, central Texas: Regional stratigraphic, Madre Oriental, in Back, W., et al., eds., Hydrogeology: tectonic, and hydrodynamic controls: Journal of Swanson, G. J., 1991, Super well is deep in the heart of Boulder, Colorado, Geological Society of America, Hydrology, v. 181, p. 251–283. Texas: Water Well Journal, no. 7 (July), p. 56–58. Geology of North America, v. O-2, p. 89–92. Pavlicek, D. L., Small, T. A., and Rettman, P. L., 1987, Technical Advisory Panel, 1990, Technical factors in Livingston, p., 1942, A few interesting facts regarding Hydrogeologic data from a study of the freshwater Edwards aquifer use and management: Report to Special natural flow from artesian well 4, owned by the San zone/saline water zone interface in the Edwards aquifer, Committee on the Edwards Aquifer (Joint Committee Antonio Public Service Company, San Antonio, Texas: San Antonio region, Texas: U.S. Geological Survey of Texas Senate and House of Representatives), 57 p. U.S. Geological Survey Open-File Report, 7 p. Open-File Report 87-389, 108 p. Tilford, N. E., 1994, Site selection: Past and present: Longley, G. 1981, The Edwards aquifer—Earth’s most Rose, P. R., 1972, Edwards group, surface and subsur- Association of Engineering Geologists Bulletin, v. 31, diverse groundwater ecosystem?: International Journal face, central Texas: Austin, University of Texas, Bureau p. 157–169. of Speleology, no. 11, p. 123–128. of Economic Geology Report of Investigations 74, 198 p. Uliana, M., and Sharp, J. M., Jr., 1996, Springflow Maclay, R. W., and Land, L. F., 1988, Simulation of flow Schenck, J. R., 1975, Ecology of the fountain darter, augmentation possibilities at Comal and San Marcos in the Edwards aquifer, San Antonio region, Texas, and Etheostoma fonticola (Osteichthyes: Percidae) [M.S. thesis]: springs, Edwards aquifer: Gulf Coast Association of refinements of storage and flow concepts: U.S. Geologi- San Marcos, University of Southwest Texas, 100 p. Geological Societies Transactions, v. 46, p. 423–432. cal Survey Water-Supply Paper 2336-A, 48 p. Schueler, T., 1994, The importance of imperviousness: U.S. Fish and Wildlife Service, 1984, San Marcos River Maclay, R. W., and Small, T. A., 1986, Carbonate geol- Watershed Protection Techniques, v. 1, p. 100–111. recovery plan for San Marcos River endangered and ogy and hydrology of the Edwards aquifer in the San threatened species—San Marcos gambusia (Gambusia Sharp, J. M., Jr., 1990, Stratigraphic, geomorphic and Antonio area, Texas: Texas Water Development Board georgei Hubbs and Peden), fountain darter (Etheostoma structural controls of the Edwards aquifer, Texas, U.S.A., Report 296, 121 p. fonticola Jordan and Gilbert), San Marcos salamander in Simpson, E. S., and Sharp, J. M., Jr., Selected papers (Eurycea nana Bishop), and Texas wild rice (Zizania Mahler, B. J., and Lynch, F. L., 1996, Characteristics of on hydrogeology: Hannover Germany, International texana Hitchcock): Albuquerque, New Mexico, 109 p. mobile sediment in a karst aquifer: Geological Society Association of Hydrogeologists, v. 1, p. 67–82. of America, Abstracts with Programs, v. 28, no. 7, Veenhuis, J. E., and Slade, R. M., Jr., 1990, Relation Sharp, J. M., Jr., and Clement, T. J., 1988, Hydrochemi- p. A-479. between urbanization and water quality of streams in cal facies as hydraulic boundaries in karstic aquifers— the Austin area, Texas: U.S. Geological Survey Water- McKinney, D. C., and Sharp, J. M., Jr., 1995, Springflow The Edwards aquifer, U.S.A., in Proceedings of the 21st Resources Investigations Report 90-4107, 64 p. augmentation of Comal and San Marcos Springs, Texas: I.A.H. Congress, Karst Hydrogeology and Karst Environ- Phase I—Feasibility study: Austin, Texas, Center for ment Protection, Guilin, People’s Republic of China: Manuscript received March 10, 1997; revision received Research in Water Resources, University of Texas, Beijing, Geological Publishing House, v. 2, p. 841–845. June 11, 1997; accepted June 13, 1997 ■ Technical Report CRWR 247. Slade, R. M. Jr., Dorsey, M. E., and Stewart, S. L., 1986, Meinzer, O. E., 1923, Outline of ground-water hydrol- Hydrology and water quality of the Edwards aquifer ogy with definitions: U.S. Geological Survey Water- associated with Barton Springs in the Austin area, Each month, GSA Today features a short Supply Paper 494, 71 p. Texas: U.S. Geological Survey Water-Resources Investi- gations Report 86-4036, 117 p. science article on current topics of gen- Menard, J. A., 1995, Bibliography of the Edwards eral interest. For guidelines on submitting aquifer, Texas, through 1993: U.S. Geological Survey Small, T. A., Hanson, J. A., and Hauwert, N. M., 1996, Open-file Report 95-336, 75 p. Geologic framework and hydrogeologic characteristics an article, contact GSA Today Science Oetting, G. C., 1995, Evolution of fresh and saline of the Edwards aquifer outcrop (Barton Springs seg- Editor S. M. Kay, Cornell University, waters in the Edwards aquifer, central Texas: Geochemi- ment), northeastern Hays and southwestern Travis (607) 255-4701, fax 607-254-4780, cal and isotopic constraints on processes of fluid-rock Counties, Texas: U.S. Geological Survey Water- Resources Investigations Report 96-4306, 15 p. E-mail: [email protected].

GSA TODAY, August 1997 9 Penrose Conference To Address Crustal Differentiation

A Geological Society of America Penrose Conference, The other three days of the “Processes of Crustal Differentiation: Crust-Mantle Interactions, conference will consist of field ITALY Melting, and Granite Migration through the Crust” will be held trips into the Ivrea Zone. The July 4–11, 1998, in Verbania, Italy. The conveners chose this loca- field days will be an integral part tion because the Ivrea Zone is well exposed in the surrounding of this meeting, providing opportu- areas and these rocks represent a section of middle to lowermost nities for direct observation of the different continental crust in addition to basaltic underplate or upper levels in the crust and for discussion. The mantle. This meeting will use the Ivrea Zone as a template in mix of field observation and key speakers from which to focus on major processes of continental growth; the different disciplines is intended to promote inter- chemistry and dynamics of partial melting in the lowermost disciplinary interaction for a better understanding of crust and upper mantle (including crust-mantle interactions), the nature and growth of the continental crust. segregation of melt from the lowermost crust, and migration and This approach also provides an excellent envi- transfer of magma upward through the crust. Discussions will ronment for active discussion and learning. center on processes active from the middle crust into the upper The main goal of the conference is to provide mantle and on key questions that enhance understanding of the a current assessment of our understanding of growth and evolu- current state of the research. Specific questions to be addressed tion of the continental crust by utilizing recent work from across are the following: a range of disciplines. • How does the crust respond, rheologically, to such continental The conference is limited to 80 participants. Interested grad- growth processes as partial melting and magma transfer? uate students are encouraged to apply; some partial student subsi- • What geochemical signatures can be used to indicate crustal dies will be available. The registration fee, which will cover lodg- growth during active deformation? ing, meals, field trips, and all other conference costs except • What is the possible range in rates of melt segregation? personal incidentals is not expected to exceed $700. Participants • What are the specific links between the petrologic and struc- will be responsible for transportation to and from the conference. tural (kinematic and dynamic) expressions of melt migration? Further information on travel will be provided in the letter of • What do we really need to know to develop tests of models for invitation. melt segregation and migration? All participants will be encouraged to present a poster on • What kind of models are even testable? current research relevant to the topic of the meeting, and signifi- The talks (a mixture of keynote and specific examples of cur- cant time will be given to view them. rent research) and discussions will be split into separate sessions Co-conveners are: Tracy Rushmer, Dept. of Geology, representing the different levels in the crust and upper mantle University of Vermont, Burlington, VT 05405, (802) 656-8136, and will address these questions and others. fax 802-656-0045, [email protected]; Michael Brown, Out of the six full days for the Penrose Conference, three Dept. of Geology, University of Maryland at College Park, days are for field excursions and three days are for inside activi- College Park, MD 20742, (301) 405-4080, fax 301-314-9961, ties. The first evening (July 4) and three days of the conference [email protected]; George Bergantz, Dept. of Geological will be in the Hotel Castagnola, where several speakers will Sciences, University of Washington, Seattle, WA 98195, (206) address crustal growth processes, but from the viewpoint of dif- 545-4972, fax 206-543-3836, [email protected]. ferent expertise and methodologies. Subjects of the lectures and Application deadline is January 15, 1998. Invitations discussions will range from large-scale tectonic modeling and will be mailed to participants by February 15, 1998. Potential isotopic studies of field examples to experimental petrology participants should send a letter of application to Tracy Rushmer and crustal rheology. Few lectures are planned, so that more (address above), including a brief statement of interests, the rele- time will be available for panel discussions, poster presentations, vance of the applicant’s recent work to themes of the meeting, and group discussions. and the subject of any proposed poster presentation. ■

Now It’s Easier For You To Help Shape GSA’s Future!

You will soon receive the 1996 GSA and GSA Foundation Annual Report. Voting members will also receive the new 1997 Corporate Ballot as a center section with a self-mailer. We have even pre-paid the postage for your convenience. We ask that all eligible members of the Society, including Teacher Associ- ates (now Teacher Members) and Student Members, take a moment to vote for the Officers and Councilors that will help shape GSA’s future for the next several years. Just detach the ballot, fill it out, fold, seal and drop it in the mailbox. The ballot must be postmarked by September 15, 1997, to be valid, and don’t forget your signature. Remember, your vote counts!

10 GSA TODAY, August 1997 EDMAP Program: Training Tomorrow’s Geologic Mappers

William C. Burton, U.S. Geological Survey, Reston, VA 20192 Robert D. Hatcher, Jr., Department of Geological Sciences, University of Tennessee, Knoxville, TN 37996

The National Cooperative Geologic Mapping Program (NCGMP), administered by the U.S. Geological Survey, has established a program to provide financial support for university graduate students who are doing thesis research that focuses primarily on geologic mapping. The EDMAP program was established as a component of the NCGMP by the National Geologic Mapping Act of 1992, which recognizes the importance of geologic mapping for our nation’s well-being, and which stipu- lates that a portion of the funding for the NCGMP should be dedicated to training a new generation of geologic mappers. The other components that receive major funding are STATEMAP, requiring a 50-50 match with state funds, FEDMAP, and SUPPORTMAP. The latter two support mapping by USGS scientists and development of a national geologic map data base. The EDMAP program involves a cooperative agreement between the USGS and a participating university in which costs related to field research are split 50-50. A faculty supervisor (principal investigator), together with up to three graduate students, submits a proposal that requests support for as many as three geologic mapping projects. The proposal is then university funding. The matching funds submitted to the USGS through the usual can include faculty salaries and university college- or university-sponsored programs overhead. Both NCGMP and university Those interested in participation office. As part of the project, each student funding should be restricted to field- in the EDMAP program should is expected to produce a new geologic map related expenses such as housing, trans- contact Nancy Zeigler at at a scale of 1:24,000 or larger, typically portation, supplies, food, and field-season the USGS in Reston, Virginia, covering an area up to the size of a 7 1/2- salaries. Limited laboratory expenses such (703) 648-6904; minute quadrangle. EDMAP projects in as preparation of thin sections or com- [email protected], every state must be consistent with the puter time for digitization are also permit- for more information and a goals of that state’s geologic mapping pro- ted. No faculty salaries will be paid by copy of the current Request for gram and with the goals of the NCGMP, NCGMP funds, but university overhead (at Proposal (RFP). Summaries of and a letter of support from a State Geolo- off-campus rate) is permitted in the current EDMAP projects can be gist, USGS Project Chief, or the NCGMP request. Proposals must nonetheless found on the NCGMP home page at Coordinator must be part of the submittal. include a detailed mentoring plan that http://ncgmp.usgs.gov, Accountability is a hallmark of the involves frequent visits by the faculty and a downloadable copy of the RFP EDMAP program: projects are funded on a supervisor to the student(s) in the field. for FY 1998 is available at that site. year-by-year basis, and maps are submitted EDMAP program announcements are to the NCGMP at the end of each funding sent out the first week in September, and year. Each student may take up to two proposals are due on December 1 of each pated in the program to date over a broad years to complete his or her mapping pro- year. A peer-review panel consisting of five range of issues that are addressed by ject, but an interim map that is reviewed university faculty, two State Geologists, EDMAP projects (see chart). for progress is required at the end of the and three USGS representatives review the The EDMAP program is unique among first year as a prerequisite for second-year proposals and meet in early January to research grant programs in its emphasis on funding. The final product should be of determine awards and funding levels. Last the development of geologic mapping “open-file” quality (uncolored ozalid or year 38 proposals containing 56 mapping skills and the production of new geologic xerox copy) and include description of projects were submitted; funding requests maps. The program addresses the growing map units, explanation of symbols, corre- totalling $732,336. The available USGS lack of these skills among geology gradu- lation of units, and one or more cross sec- funds for FY 1997 total are $370,882. The ates and provides funding for what many tions. Digital geologic maps are encour- panel recommended 32 proposals for feel is a vital but poorly supported disci- aged but not required. funding; awards per student ranged from pline within the geological sciences. ■ In the proposed budget, USGS fund- $6,000 to $12,000. Thirty-nine universities ing should be matched or exceeded by in the conterminous U.S. have partici-

GSA TODAY, August 1997 11 WASHINGTON REPORT a warming of as much as 1 °C per decade would affect shallow subsurface ice in the Bruce F. Molnia continuous permafrost zone. The group concluded that in the short term, melting Washington Report provides the GSA membership with a window on the activities of ice could result in the differential set- of the federal agencies, Congress and the legislative process, and international interactions tling or collapse of roads, airport runways, that could impact the geoscience community. These reports present summaries of agency buildings, and other infrastructure, includ- and interagency programs, track legislation, and present insights into Washington, D.C., ing the Trans-Alaska Pipeline. In the long geopolitics as they pertain to the geosciences. term, following the melting of shallow subsurface ice, construction in the Arctic would be significantly less expensive and less complicated. Regional Climate Change Workshops— Writing groups at each workshop will produce a report containing: (1) a descrip- Ammunition For Kyoto tion of the region’s environmental, demographic, and economic conditions; (2) an identification of vulnerabilities to climate In December 1997, Kyoto, Japan, will Earth system and thus provide a sound sci- variability and climate change; (3) an host the Third Conference of the Parties entific basis for national and international identification of adaptation and resource to the United Nations Framework Con- decision making on global change issues. management options; (4) a definition of vention on Climate Change (COP3). The The national-scale scientific assessments that research needs for improving estimates of purpose of the conference will be to for- will result from the regional workshops are regional vulnerabilities, understanding the mulate measures to curtail global warm- authorized in the GCRA. consequences of climate variability and ing. A primary goal is to adopt a protocol The regions selected for the first change, and analyzing viable response that defines target figures to reduce green- group of workshops were chosen on the options; and (5) written input for the house gas emissions after the year 2000. basis of a combination of scientific interest regional science assessment. About 5,000 participants from 190 coun- and “near-term opportunities for hosting In spite of the fact that three work- tries, institutions, international organiza- events.” The first workshop was held at shops are still to be held, a meeting of tions, and nongovernmental organizations Fort Collins, Colorado, in late May, while technical experts was held July 29– (NGOs), as well as thousands of journalists the second, which focused on impacts on August 7, at the Aspen Global Change will attend. The U.S. delegation will be the western Arctic including Alaska, was Institute. Its purpose was to synthesize headed by Vice-President Al Gore. held in Fairbanks in early June. I partici- the results of the first four regional work- Originally formulated in 1992, the pated in the Fairbanks meeting. shops and begin planning for the national United Nations Framework Convention Additionally, a southeastern U.S. science assessment. A National Workshop on Climate Change went into effect in workshop, attended by the vice-president, on Climate Change Impacts will be con- March 1994. It has been ratified by more was held in Tennessee in late June, and a ducted in Washington, D.C., November than 160 countries, including the United Pacific Northwest workshop was held in 10–12. It will relate regional results to States. In 1995, the Intergovernmental Seattle in mid-July. Three more workshops national-scale impacts and continue plan- Panel on Climate Change (IPCC) released (Southwest, New England, and Mid- ning for the national science assessment. a report that concluded that global warm- Atlantic), will be held in September. A second group of regional workshops, ing was significantly impacting many Each workshop has at least one local covering the remaining regions of the aspects of the Earth system. The IPCC academic organizing institution and at United States, will be conducted by mid- report recommends pursuing a wide range least one coordinating Federal agency. 1998. The national science assessment is of actions to mitigate climate change, Additional information about the work- scheduled to be completed during 1999, such as eliminating fossil fuel subsidies, shops can be found on the USGCRP and it will be the U.S. contribution to the increasing energy efficiency measures, Coordination Office home page (http:// IPCC Third Assessment Report. preserving forests, and increasing reliance www.usgcrp.gov). This regional workshop process is not on renewable energy technologies, such as Selection and invitation of partici- occurring in a vacuum. Both the environ- wind and solar power generation. Devel- pants is the responsibility of the regional mental community and the industrial and oping a strategy for mitigation and adapta- organizers. The workshops are designed business community are closely watching tion also appears to be the view of the to include participation from the research the outcome. Beginning in June, multiple- Clinton Administration. and stakeholder community. The term page newspaper ads, radio announce- To provide input for formulating “stakeholder” is used in the broadest ments, Internet messages and home pages, an official U.S. government strategy for sense. It includes individuals from federal, and detailed television reports began to the COP3 meeting and to understand state, and local governments; universities appear. Their purpose was to try to rally the national-scale consequences of global and laboratories; industry, agricultural, support either for or against a strong U.S. change, the U.S. Global Change Research and natural resource managers; non- position in Kyoto. For instance, the June Program (USGCRP) is sponsoring a series governmental organizations; and others. 10 issue of the Washington Post contained of seven regional workshops. The work- Each workshop will focus on specific a three-page advertisement signed by shops will examine the vulnerabilities of regional needs as well as issues common more than 130 presidents, chairmen, various regions of the United States to to all seven regions. For example, at the and CEOs of some of the largest compa- climate variability and climate change. Alaska workshop, which was hosted by the nies in America, under the auspices of a It will also aggregate information across University of Alaska, Fairbanks, and coor- group called the Business Roundtable. regions to support a national-scale scien- dinated by the Department of Interior, we Their statement concluded, “We strongly tific assessment. addressed what the impacts of changing urge the Clinton/Gore administration not The USGCRP was established under climate would be on: infrastructure, fish- to rush to policy commitments until the President Bush in 1989, and authorized by eries, the coastal zone, land-based ecosys- environmental benefits and economic Congress in the Global Change Research Act tems, and nonrenewable resources. consequences of the treaty proposals have (GCRA) of 1990. The program’s fundamental For example, the primary concern purpose is to increase understanding of the in the “infrastructure” sessions was how Washington Report continued on p. 13

12 GSA TODAY, August 1997 LETTER

read with great interest Eldridge Moores’s 1996 GSA Presiden- 3. The public may associate geology-related issues with tial Address [GSA Today, v. 7, no. 1, p. 7]. As a former practic- impairment of land rights that can threaten even the ordinary I ing geologist, frustrated by the difficulty in pursuing a career homeowner. For example, the U.S. government has instituted a in geology, I have a special interest in his concerns. very sensible (if subsidized) approach to flood-plain regulation I received my B.S. degree in geology in 1980 and my M.S. in in the National Flood Insurance Program. The program has been 1983. I worked for a major oil company until 1990. When I was designed to reflect statistical, scientific realities and impute the transferred from Bangkok to Los Angeles in 1990, I left the com- costs of flood-plain development to the risk taker (i.e., it’s pany after realizing that my salary was insufficient to allow me designed to avoid “rewarding” risk takers with postdisaster aid). to live reasonably close to my downtown office. After earning a Yet the program is popularly perceived as unwarranted govern- degree at the UCLA School of Law, I practiced law in Tucson for ment regulation and interference with property rights. nearly two years before returning to Bangkok to practice law with 4. Geologists suffer in industry by the perception that they a large New York-based firm. are the poor stepchildren of engineers. Industry may not value The profession of geology is in a tragic state. My friends who geologists because, in comparison with engineers, the supply of are still with the major oil company have now lived with 13 years geologists is great and the demand is small. Further, in compari- of layoffs. In the years since my departure, many innovative and son with engineers, few geologists receive academic training effi- highly qualified geologists have also left voluntarily, unable to raise ciently oriented toward industrial applications. This approach to families in the unstable environment facing the oil industry. Only geology education, however justified, may contribute to indus- a small number of my friends from the University of Arizona’s try’s poor perception of the science and result in reduced support large graduate program are still practicing geologists. Those who from industry. Further, industry management may neglect invest- still practice struggle to do excellent jobs for companies that face ment in geologists when resource exploration is more efficiently uncertain futures. To supplement Moores’s academic perspective, pursued in financial markets. I offer the following industry-oriented problems facing geologists: I recently observed negotiations related to a large infrastruc- 1. Geology suffers from its association with exploitative ture project. The geologic analysis of the site was poor, calculated resource industries and development of marginal lands. Although only to produce a satisfactory “executive summary” for project popular thought may now be more pro-business than in the past, investors. In the squeeze to make a living in an unfavorable envi- resource industries continue to suffer a poor public image. Geolo- ronment, geologists may face compromises in the excellence of gists are regularly associated with strip mining, ground-water their work that will further contribute to the poor perception of pollution, and sensational mishaps such as Malibu landslides, geologists in industry. alleged conscripted labor in Burma, Bre-X, and the like. The pub- Geology is indeed one of the most fascinating natural sci- lic may justifiably question why, if geologists are so often associ- ences—witness the popularity of the geology-oriented national ated with huge, moneymaking ventures or preventable disasters, parks. I appreciate Moores’s observation of the “Eureka!” aspect they should receive generous subsidies from the government. of geologic thought and his perception that geological analysis 2. The public may associate geologists working on hazard differs from the purely analytic method of enquiry that prevails abatement with the disasters they seek to mitigate or with the huge in many other sciences. For me, this provided an exceptional expenditures required to repair environmental damage. Environ- background for practicing law. It is too bad that it didn’t more mental law seems to abstract underlying scientific issues into regu- readily provide for a career in science. latory wrangling and wars among “potentially responsible parties.” Rob Risley This may reduce industry’s need for accurate geologic analysis. Bangkok, Thailand

Washington Report continued from p. 12 become the most economically devastat- to how the U.S. will assist other nations in ing federal policy blunder of the decade.” significant steps toward achieving the joint Elsewhere, Internet traffic from purpose of stabilization.” The GCC been thoroughly analyzed. Americans pro-environmental NGOs carries banners response shows how large the difference in should have the opportunity to voice stating, “Act Now! Environmentalists fear philosophy is between the two sides. What- their opinions in this important debate.” weak U.S. stance may hamper global ever position the vice-president and the Another group, the Global Climate warming talks.” Much of their concern is USGCRP take, they will fail to satisfy a large Coalition (GCC), a similar organization based on statements by President Clinton, percentage of the stakeholders. According of business trade associations and private in recent speeches, that his Administra- to GCC, “Those who organized this effort companies “established in 1989 to coordi- tion has indicated only an inclination to today (the Scientists’ Statement), are doing nate business participation in the scien- support stabilization, but not reductions, little to advance our scientific knowledge of tific and policy debate on the global cli- in heat-trapping gases by 2010–2015. global warming but are doing a great deal mate change issue,” has also issued a On June 23, a “Scientists’ Statement on to politicize this important issue through statement and paid for many radio ads Global Climatic Disruption,” aimed at the public relations gimmicks. Political peti- in the Washington, D.C. area to lobby Kyoto meeting and signed by hundreds of tions are no substitute for an open scientific against severe limits on energy consump- members of the international scientific debate and rigorous economic analysis.” tion. The statement by Gail McDonald, community was released. In it, the signato- Stay tuned for more information. president of the GCC concludes, “Presi- ries state, “Human-induced global climatic If you have comments or questions dent Clinton has a unique opportunity in change is under way. [We] … observe that on this Washington Report or others the coming days to demonstrate true lead- the further accumulation of greenhouse contact Bruce Molnia, [email protected] ership by encouraging the leaders of the gases commits the earth irreversibly to fur- or [email protected], (703) 648-4120, G8 and representatives to the U.N. to care- ther global climatic change and consequent fax 703-648-4227, Deputy Chief, Interna- fully study the scientific and economic ecological, economic and social disruption. tional Programs Office of the Chief Geolo- implications of any climate agreement … [We] urge the United States [to] enter gist, U.S. Geological Survey, 12201 Sunrise before taking action. If he does not, he that meeting with a clear national plan to Valley Dr., Rm. 3A312, 917 National stands on the precipice of what may easily limit emissions, and a recommendation as Center, Reston, VA 20192. ■

GSA TODAY, August 1997 13 SAGE REMARKS Honey, I Shrunk the Class: Thoughts on Personalizing Large Lecture Classes

Jonathan Levy, Department of Geology, Miami University

Last year I was awarded the BIGGS was more than a little dubious. Like many (I guess they are a bit preoccupied). The award for early-career earth science teach- people, I have trouble remembering some- sheet is passed up and down the rows. ers. For this I am deeply honored and one’s name 30 seconds after an introduc- I am ever watchful to ensure that it is grateful to all involved. Ed Geary, Educa- tion. Still, I have had great success with passed around in a logical order. I’m sure tional Programs Coordinator for GSA, the techniques that Murray recommended. the students must write off my behavior asked me to share some of my teaching I employ them each semester in the intro- as overly fussy as I frantically leap up to philosophy and techniques. I consider ductory class Environmental Geology, grab the sheet if it’s passed the wrong way. myself new at this whole thing and am comprising about 95 nonscience majors. For a class of 95 it takes about 20 minutes therefore cautious about giving any advice The rewards have been tremendous. (with some diligence on my part to keep it to teachers with much more experience Knowing students’ names helps create a moving) for the sheet to make the rounds. than I have. I have given a good deal of friendlier, less intimidating learning envi- That leaves me 30 minutes to use the thought to what contributes most to my ronment. The changes in students’ atti- sheet as a seating chart and to associate teaching and have decided that one factor tudes and demeanor are obvious when as many names with faces as I can. is my success in making large classes feel you call them by name (either when their Associating names with faces is a like small ones. Some of this is due to such hands are raised or when they’re not). matter of a combination of thinking up intangibles as feeling at ease in front of They immediately feel less like mere mnemonic devices and using simple rote large groups—i.e., being a bit of a ham. numbers, and they feel that you care memorization. It comes in very handy But there are some tactics that might be about their learning. As a result, they to have already associated first and last worth sharing, most of which I borrowed begin to care more about their own learn- names because it might be either name from others and all of which contribute to ing. Although I haven’t performed any that lends itself to an easy mnemonic. getting around the formal barriers set up controlled experiments, I also believe that For example, Leon Jones in the third row in a traditional lecturer and student for- calling students by name encourages class might have red hair (or a bony face, for mat. These tactics can be broken down attendance and participation in question- that matter). The fact that I am a fan of into the Murray technique of learning stu- and-answer dialogs. When Murray told the musician Leon Redbone makes this dents’ names, cooperative learning tech- me his methods, he presented them as a name one I won’t easily forget. Most, of niques, and what my wife refers to as the magic trick and swore me to secrecy, but course, are not so easy or so polite. For Columbo technique. Allow me to explain. since he is a statistician and will probably the protection of my former and future never read GSA Today, I don’t see the harm students (and myself), I will refrain from POWER OF NAMES: in sharing the information with you. If giving any real examples. Easy ones to THE MURRAY TECHNIQUE you see Murray, please don’t tell him that remember are also embarrassingly goofy. I wrote this. Now that I have done this a few times, I When I began graduate school at the Step one is to become familiar with find myself getting nervous on exam day. University of Wisconsin, my advisor sug- the class names, independent of their The pressure is on to quickly and cre- gested I take a statistics class. I dutifully faces. Simply spending some time reading atively come up with good mnemonic signed up for one thinking it would be and reciting the class list helps associate devices. However, I also look forward to useful, but not terribly exciting. I was students’ first names with last names. being able to call my students by name. wrong. Not only was the class full of Even in the first few weeks of the class you On average, while not as good as Murray, invaluable material, but it was also excit- may be able to use this information, for I have found that by the end of the first ing and fun. Of course, what made it such example, when handing back papers. You exam, I have learned about half—40 to a great experience was the talent of the may ask a student “What is your last name 50—of the names, some with mnemonics, professor, Murray Clayton, who would go again? Summers. Right. Here you go, Mary others by rote memorization. Here’s some on to become a teaching mentor for me. Ann.” To the students, this can appear as more magic—learning half the names is Since I was the nerdy, pesky type who if you have magically already learned who enough to give the impression that you asked a lot of questions and went to office they are. The most important aspect of know all the names. I repeat the process hours, I was not surprised that Murray learning to associate first and last names during the second exam, concentrating on quickly learned my name. As the semester is that it prepares you for the next step. the faces I have yet to learn. By the end of went on, however, I was surprised to find Step two occurs on the day of the first the second exam, I will typically know 75 that Murray seemed to know everyone’s exam. I have chosen not to generally take to 85 names out of around 95. The hardest name. How this was possible in a lecture attendance or have a seating chart, but by to learn are the young men with the hats. class of roughly 130 students I did not this time, students tend to sit where they During exams, their heads are down mak- know, but I did know that along with sit. There is typically very little shuffling ing it very difficult to see their faces and Murray’s gracious, easy-going style, it around after the first two weeks. During to associate their faces with their names. helped transform the lecture into an inti- the first exam I pass around an “atten- If they wore the same hats everyday, I’d be mate, seemingly small-class experience. dance sheet.” It’s not really an attendance OK, but that seems not to be the case. On When I came to Miami University sheet. In fact, exam days are the only the same note, be wary of using hair styles as an assistant professor in 1994, I asked days where an attendance sheet provides in your mnemonics, for they can be too Murray for any advice he could give me. redundant information. The funny thing ephemeral. The boys (or men) that shave The first thing he recommended was that is, no student has yet questioned why I I should learn all my students’ names. I need an attendance sheet on exam days SAGE Remarks continued on p. 15

14 GSA TODAY, August 1997 SAGE Remarks continued from p. 14 Educom Medal Award Winner Named or grow their beards midway through the course also cause me grief. Michelle N. Lamberson is the winner of the Educom Medal Learning each student’s name makes for her pioneering work in World Wide Web resource devel- each one feel a bit more like an individual opment for undergraduate geoscientists. The Web site and someone whose efforts are appreci- Lamberson has developed for the Department of Earth ated. It’s a bit of work, but judging from and Ocean Sciences, University of British Columbia, at the number of students who comment on http://www.science.ubc.ca/~eoswr/ includes course Web it at the end of the semester, it is time well sites, interactive learning modules, exercises, discipline- spent. specific databases, and developer tools. The Educom Medal was established in 1994 to improve USE OF COOPERATIVE LEARNING the quality of the undergraduate learning experience and After having gone through the effort to promote the effective use of information technology in to learn 92 names my first semester, I dis- higher education. Each year, Educom, a consortium of 600 covered that students who had sat next colleges and universities, selects disciplinary societies as partners, whose representa- to each other three days a week for 15 tives choose a winner. This year, Educom has chosen GSA as a partner in selecting an weeks often didn’t even know each other’s individual who has made a significant contribution to transforming undergraduate names. This discovery, as much as any- learning in geology through information technology. thing, led me to think that something was Michelle Lamberson is a lecturer in the Department of Earth and Ocean Sciences and missing from the learning community I the Educational Technology Coordinator for the Faculty of Science at the University of was trying to foster. Of course, what I had British Columbia in Vancouver. She received her Ph.D. in geology at the University of stumbled upon was the rich and complex British Columbia in 1993. She was a postdoctoral fellow at the University of Arizona, subject of cooperative learning. While and she taught several geology courses at the University of British Columbia and the knowing the names of most of the stu- University of Victoria. She says she first looked at the World Wide Web in October of dents establishes a direct and personal link 1994 and saw its potential for improving the learning environment for visually ori- between me and the students and makes ented learners in geoscience. She was hired as a four-month postdoctoral teaching fel- the students feel more like individuals, it low to investigate the effectiveness of the Internet as a teaching and learning medium is only the first step in increasing individ- for geoscience students in January 1995, a role that evolved into her current position. ual accountability of student learning. The use of cooperative learning tech- GSA President George Thompson will present the Educom Medal to Michelle Lamber- niques is the next step in the process, son at the Presidential Address and Awards Ceremony at the GSA Annual Meeting in and I have only begun to experiment Salt Lake City, Utah, on October 20, 1997. Lamberson will then travel to the Educom with these techniques. Annual Meeting in Minneapolis, Minnesota, October 28–31, to participate in the My first and simplest application of Educom awards presentation and receive a check for $2,500, and a bronze desk cooperative learning was to extend the statue. Socratic method to self-formed groups instead of individuals (also known as Think-Pair-Share; Macdonald, 1995). I am, no doubt, not alone when I admit that, midway through the course, I was lectur- drawing flow and equipotential lines and too often, I ask a question and am initially ing (in traditional style) on a topic that answering questions. I roamed around the met with deadly silence. (While always mainly involved interpretation of numer- room guiding the groups through their tempted to answer the question myself ous figures showing the effect of various problems. What struck me most was that and move on, I try to withstand the silent hypothetical geologic settings on ground- in some groups, the students had begun onslaught until a response is given, often water flow. I found the material fascinat- working on the problems individually, with rephrasing and much coaxing). ing and perhaps naively thought the class with no communication at all. They were While the silence can sometimes occur would enjoy the lecture. I stood in front of so unaccustomed to working together when the question is too easy, student fear the class showing overheads of the figures that they did not initially know how to of a wrong response explains most of it. and explaining the relationships, only to approach the assignment. With some gen- Once in a while, therefore, I encourage observe the students getting more bored tle prodding, they began working together. students to confer with one or two people than I had ever seen them, including dur- After sufficient time for completion of the sitting nearby and see if they are thinking ing involved equation derivations. During problems, the groups reshuffled so that along the same lines. The first couple of derivations, they are at least taking notes new groups of four were formed with at times I do this, I ask that they introduce and are, therefore, somewhat involved least one representative from each of the themselves and tell their new partners a with what I am doing. With the figures, three problems. Each new group member little about themselves. In addition to per- however, all they could do was watch me was responsible for teaching his or her haps eliciting more responses, this tactic make the interpretations. I realized that problem to the other members of the new is usually viewed with some surprise and guided interpretation of these same figures group. The idea is a simple one: teaching good humor and may help make the lec- in interactive groups would be a much a concept requires a deeper understanding ture seem less formal and intimidating. more effective method of conveying an than is normally required for doing an It might also lead to fostering friendships understanding of the material. I therefore assignment. To complete all the problems, between students and more cooperation designed activities based on the “jigsaw” students must pay attention to and ask outside the classroom. technique as described, for example, by questions of their fellow students. I closed Recently I’ve begun experimenting Tewksbury (1995). The class was divided the exercises with student oral presenta- with more sophisticated applications of into nine groups of four. Each group was tions using overheads to make sure no cooperative learning. This experimenta- assigned one of three figure-based prob- major concepts were missed. tion occurred in an introductory hydro- lems to work on, so three groups were geology class with about 35 to 40 juniors, working on each problem, which involved seniors, and graduate students. About SAGE Remarks continued on p. 16

GSA TODAY, August 1997 15 SAGE Remarks continued from p. 15 dents are encouraged to participate as TV series in which the detective Columbo individuals and not anonymous listeners used a combination of techniques meant I believe my ventures into coopera- and note takers, and, therefore, share simi- to give the murderer a false sense of supe- tive learning, and especially the jigsaw lar goals to learning student names. Next riority and security before sending him method, have been very successful. Stu- semester, I plan to extend these tech- or her to prison for life. OK, so that’s not dents seemed grateful for the experience niques to my large introductory class. exactly my aim with the students, but I do (especially when similar problems were Because the classroom I use does not lend mean to put them at ease and make even a included on the final exam). In end-of- itself to students moving around, modifi- large lecture hall a friendly environment. semester evaluations, students rated the cation will be necessary. The goals, how- Like Columbo, I engage in somewhat self- exercises “excellent” (44% of respon- ever, will be the same: involve the stu- deprecating humor, and I will embark on dents), “good” (44%), and “fair” (11%) dents more actively and cooperatively personal stories of travels or mishaps to compared to a normal lecture. Like many in thinking about the course material. get my geological points across. The key before me, however, I found that the exer- to Columbo’s success was that he appeared cises took much more time than I origi- COLUMBO TECHNIQUE to digress, when actually he was always on nally expected (actually, about twice as a direct course toward well-developed Along with emphasizing my getting long). There is no doubt that using such objectives. As I mentioned at the outset, to know the students and the students methods results in getting through less my wife came up with the name, and that, getting to know each other, a third com- lecture material. To work successfully, it of course, is part of the point. Part of ponent to breaking down traditional class- requires students’ coming prepared to Columbo’s style was to bring his profes- room barriers is to let the students know class, having done the appropriate read- sional relationships to a personal level by a bit about me and see me as a person, ing. I am, so far, just a dabbler in these telling stories regarding and giving cre- not just a lecturer. At grave risk of dating techniques. I see them as a way of break- myself, I’m calling it the Columbo tech- ing up the normal lecture routine. They nique. You may or may not remember the SAGE Remarks continued on p. 17 help create an atmosphere in which stu-

GSAF UPDATE Valerie G. Brown, Director of Development, GSA Foundation

FROM THE GROUND UP their GSA colleagues, from corporations Some of the applications are general that engage in the business of geology, in nature. The SAGE funds, for example, In recent months, we’ve reported from foundations that respect and support are directed to enhancing public under- both on 1996 fund-raising results and GSA’s programs of education and outreach, standing and appreciation of geoscience. on cumulative revenue during the Second and from government investment in the This broad objective encourages unusual Century campaign from 1992 through importance of geoscientific excellence. but valuable activities such as April of 1997. So what’s the point of all The funds are applied to several pur- • designing and presenting summer work- this money? poses—above all, to education. Of the 67 shops for middle school teachers from The GSA Foundation has 67 gift funds, 35 are dedicated to assisting stu- all over the country needing to improve funds. The funds originate from several dents of all ages to become intellectually their command of earth science curricu- sources—from individuals, many of them or even professionally engaged in the lum and technological teaching aids; GSA members who create significant gifts geosciences. • recruiting GSA member volunteers to or who donate in honor or memory of serve as expert mentors for schools, classrooms, or individual students in their communities; • creating the Colorado Rock Park, a geo- GSA Foundation logical garden that will provide interac- 3300 Penrose Place tive instruction for visitors of all ages P.O. Box 9140 about the shape and structure of the Boulder, CO 80301 state’s natural environment and will (303) 447-2020 establish a model for similar installa- [email protected] tions in other parts of the country. These activities are supported by the full spectrum of donors. Enclosed is my contribution in the amount of $______. Please add my name to the Century Plus Roster (gifts of $150 or more). Please credit my gift to the ______Fund. PLEASE PRINT Digging Up the Past Name ______I stepped on a boulder at the foot of a glacier during the Address ______1960 IGC and learned about thixotropy—we City/State/ZIP ______both sank. Phone ______—Virgil E. Barnes

16 GSA TODAY, August 1997 SAGE Remarks continued from p. 16 traditional lecture format in such a way as to more involve the student in his or her ative credits to his wife. For example, I own education. They are not revolution- About People enjoy telling the students that it was my ary in that they do not deviate much from GSA Fellow John A. Cherry, wife, not me, who came up with a good an overall lecture format. Perhaps more University of Waterloo, Ontario, mnemonic device (a first-letter analog) for can be achieved with further deviation Canada, has been awarded the remembering the names of the epochs of from the lecture format and more sophisti- William Smith Medal by the Geologi- the Tertiary and Quaternary periods (peo- cated application of cooperative learning cal Society (of London), for excellence ple everywhere order many pizzas, piping techniques. However, I believe that our in contributions to applied and eco- hot). Geology, more than other disci- knowing the students, the students know- nomic aspects of geoscience. plines, lends itself to the Columbo tech- ing each other, and the students knowing nique, because we get to show slides of us help make lectures more personal and Member Robert Lamonica, exotic locations. I try to include slides that draw students into discussions, activities, Trumbull, Connecticut, has been show me, my friends, and my wife, and and their own learning. named executive vice president and students have often told me how much chief operating officer by the ground- they enjoy this part of the lecture and REFERENCES water and environmental engineering how it helps involve them more in the Macdonald, H. R., 1995, Cooperative-learning activities services firm, Leggette, Brashears & material. Plus, as I admit to my students, in large entry-level geology courses: Journal of Geologi- Graham. who could ask for a better job than one in cal Education, v. 43, p. 341–345. The Association of Engineering which you get to show your travel slides Tewksbury, B. J., 1995, Specific strategies for using Geologists has appointed a new execu- without being socially ostracized? the “jigsaw” technique for working in groups in non–lecture-based courses: Journal of Geological tive director: GSA Fellow Norman R. All the techniques outlined have ■ Education, v. 43, p. 322–326. Tilford, Texas A&M University. the same general goal: to improve on the

GSAF Update continued from p. 16 Grants from the Boettcher Founda- Because of the large role tion, El Pomar Foundation, and the of agriculture and an abun- The Donald L. and Carolyn N. National Science Foundation have dance of natural resources, the nation Biggs Excellence in Earth Science enabled GSA to launch the science and could prosper even if many young people Education Fund was established in 1990 technology workshops for teachers, a did not develop their full intellectual in memory of Donald L. Biggs. Upon the labor- and equipment-intensive project capacities.… Now we face a future in death of his wife, Carolyn, in 1991, her that wouldn’t have been feasible without a which we must increasingly turn to high- name also was incorporated. Income from major infusion of capital. technology products as a source of eco- this endowment is committed to the SAGE In short, the point of the money is nomic security.” To prepare for this world, initiatives, serving as a permanent fulfilling a mandate. excellence in scientific and technological reminder of the generosity of the Biggs man’ date, n. From the Latin manda- education is of the highest priority. family and friends. tum, a charge, command, commission; Your gifts to GSA fuel our contribu- Several hundred individuals lit., to put into one’s hand; manus, tions to such education. making annual gifts directed their use to hand, and dare, to give. SAGE programs. As recently noted in the journal THIS MONTH’S BUMPER STICKER: BHP Minerals has made and Science, “The U.S. educational system was Take good care of the future, because renewed vital corporate gifts used, in part, designed a century ago to prepare children that’s where we’re going to spend the rest as seed money for developing the Rock to hold jobs and raise families in a world of our lives. ■ Park. that relied primarily on physical labor.

Donors to the Foundation, May 1997

Cady Award John T. Dillon Penrose Conferences Sharon A. Geil Alfred G. Fischer Leonard R. Wilson Alaska Scholarship American Institute Samuel F. Huffman Danny K. Hagans in memory of Dr. Award of Professional A. David Kendrick Giovanni Napoleone Robert M. Kosanke, one Alison B. Till* Geologists* Kennecott Corporation* Peter Robinson of my earliest students Reese E. Mallette Charles E. Seedorff Dwornik Planetary Research Grants Margaret W. Matlin Alison B. Till* Doris M. Curtis Geoscience Award Peter Robinson Marlene L. McCauley Memorial Stephen E. Dwornik Alison B. Till* Unrestricted Fund— Unocal Corporation/ Grover E. and GSA GEOSTAR SAGE Union Oil Company Sally Marie Murray Trevor A. Dumitru Robert F. Hudson Anne M. Trehu of California* in memory of Robert J. Irving S. Fisher Robert C. Whisonant Cordell, Edwin N. Institute for Second Century Alison B. Till Goddard, and Robert Environmental Campaign Unrestricted Fund— C. Stephenson Education James R. Clark Foundation *Century Plus Roster Peter Robinson Paul B. DuMontelle Ryo Anma (gifts of $150 or more).

GSA TODAY, August 1997 17 Institute for Environmental ENVIRONMENT MATTERS Education

Assessing Environmental Justice: The Demographics of Hazardous Waste in Los Angeles County

James L. Sadd, J. Tom Boer, Manuel Pastor, Jr., Lori. D. Snyder, Occidental College, Los Angeles, CA 90041

The concept of environmental justice median household income, median home stantial demographic inequity in TSDF addresses potentially inequitable impacts value, median rent, percentage of popula- location. A significantly larger percentage of environmental hazards on society, as tion employed in industry, unemploy- of people who live near Los Angeles well as the need for equal public access ment, percentage registered to vote (1992), County TSDFs belong to racial and to processes that can redress such impacts. population density, percentage with a ethnic minorities and are below the We used Geographic Information System high school education or less, percentage county average in terms of income, edu- (GIS) and Global Positioning System (GPS) of tract area devoted to industrial use, and cation, employment, and voting participa- technologies to document the current geo- percentage devoted to residential use. tion. Neighborhoods near TSDFs also lag graphic distribution of hazardous waste Four different aggregate tract sub- behind the county mean in value of resi- treatment, storage, and disposal facilities samples were defined to explore different dential home and rental property, and the (TSDFs) in Los Angeles County, California. definitions of the community exposed to percentage of the land in these tracts occu- We examined this pattern to test if haz- the potential hazard. TSD is composed of pied by industrial land use is four to ten ardous waste sites can be correlated with all tracts that contain at least one TSDF times the county average. Demographic, a variety of socioeconomic and demo- regardless of capacity. TSD50 includes economic, and land use differences tend graphic factors. Because an extensive per- tracts containing a large-capacity TSDF. to be greater for tracts containing large- mit and siting process is required for legal TSD50/0.5 and TSD50/1.0 are two subsam- capacity TSDFs, and evaluation of tracts operation, environmental justice problems ples that include all tracts with boundaries within a one-half or one mile radius shows associated with hazardous waste facilities within a 0.5 or 1.0 mile radius of a large- that these demographic differences persist may be at least partly rooted in political capacity TSDF. Demographic variables over a wide area. “Minority”-dominated process. For this reason, hazardous waste were summarized to produce mean and neighborhoods are much more likely to be facilities have been a particular focus of median values that describe the total pop- located near TSDFs than primarily Anglo environmental justice debate in other ulation represented by the sum of tracts (non-Hispanic white) neighborhoods. The areas. In this study, we assumed that the in each subsample. Using univariate statis- resident population of tracts with bound- presence of a TSDF poses some additional tical techniques to test the statistical sig- aries within 1 mile of a large-capacity site risk to nearby residents, particularly in nificance of the implied visual results, we comprises 8.3% of the Anglo population, case of fire, accidental explosion, earth- compared these data with similar tract- it also represents 22.0% of Los Angeles quake, or illegal discharge. level demographic means or medians for County’s minority population. Therefore, All 82 permitted Los Angeles County all Los Angeles County census tracts. more than one in five minorities live in TSDFs were used in this analysis, and dif- a census tract located within 1 mile ferentially corrected GPS was used to con- of a large-capacity TSDF in Los Angeles firm geocoded site locations. We assumed County, as compared to fewer than one in that the wide range in capacity among CAUTION ten Anglos living in similar circumstances. these facilities (0.01 to 140,000 tons annu- These results indicate a strong geo- ally) implies a significant range in poten- HAZARDOUS graphic correlation, but spatial and uni- tial health risk to nearby residents, and variate analyses cannot separate the effects that this risk is greater near large capacity WASTE of each demographic characteristic and TSDFs (>50 tons per year; n = 39). For this STORAGE determine its relative importance in facil- reason, we also explored the impact of ity location. This is particularly problem- facility size on correlation with demo- atic because many of the variables (e.g., graphic characteristics. Data used in this minority and income) are themselves study were obtained from the State of highly correlated, making it difficult to California, 1990 U.S. Census, Southern distinguish whether site location is the California Association of Governments, result of explicit income or ethnic discrim- Los Angeles County Registrar/Recorder’s ination, or perhaps a consequence of mar- Office, and commercial data sources. ket-driven opportunity costs such as real- Analysis was conducted at the census tract estate pricing and local job options (or level, and tracts listed as having no resi- some combination of both). dents were eliminated from the analysis. We also used a multivariate logit The average tract area is 2.5 square miles, This comparison of tracts with and regression to attempt to tease out the sepa- with a median of 0.5 square mile. without TSDFs reveals statistically signifi- rate effects of each variable while holding Using GIS (Arc/Info software), we cant differences by race, economic status, the others constant. Our findings include: compared demographic characteristics education, voting participation, and land (1) percentage minority and industrial of census tracts that contain or are near use. In almost every case and in each of land use are the dominant factors in large- a TSDF to the universe of all Los Angeles the four subsamples, the aggregate mean capacity TSDF location; (2) per capita County tracts. To summarize demographic demographic profile for each of the twelve income has far less effect than the previ- composition, we used 12 census variables: variables varies from the county mean at ous two variables; (3) the significance of percentage minority residents (sum of statistically significant levels, usually at percentage minority is greater with dis- African-American, Asian, Hispanic, and the 99% confidence level. The manner in Native American), per capita income, which these variables differ indicates sub- Environment continued on p. 19

18 GSA TODAY, August 1997 Penrose Conference Report Late Paleocene–Early Eocene Events in Space and Time

Co-conveners: William A Berggren, Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543; [email protected] Marie-Pierre Aubry, Institut des Sciences de l’Evolution, Université de Montpellier II, 34095 Montpellier, France; [email protected] montp2.fr Spencer G. Lucas, New Mexico Museum of Natural History, 1801 Mountain Road NW, Albuquerque, NM 87104; [email protected] abq.mus.nm.us Lowell Stott, Department of Geology, University of Southern California, Los Angeles, CA 90089; [email protected] James Zachos, Earth Sciences Department, University of California, Santa Cruz, CA 95064; [email protected]

Although it has been known for epochs constituted the most critical turn- 308 studies to meet and review the infor- more than a century that a major turnover ing point in the Cenozoic history of our mation that now exists on this subject, occurred in the terrestrial mammalian interstellar home. to subject the data from various fields to fauna near the Paleocene-Eocene epoch In an attempt to delineate clearly careful scrutiny and analysis, and to inte- boundary, it is only relatively recently that the location and distribution in space grate information from disparate areas. apparently simultaneous, equally impor- and time of these changes, and to deci- The Penrose Conference was held April tant evolutionary turnovers among pher the cause-and-effect relationships 24–29, 1997, at the Rio Grande Inn, marine invertebrates and protists have involved and which resulted in global Albuquerque, New Mexico, cosponsored been recognized. Subsequent to the dis- warming, International Global Correlation by GSA and the New Mexico Museum covery of a sharp late Paleocene extinction Project (IGCP) 308 was initiated (1989; of Natural History. Fifty-five scientists event in deep sea benthic foraminifera— president: Marie-Pierre Aubry) and funded (including 10 graduate students receiving the most notable evolutionary event for a period of 5 years by IUGS and partial support from GSA) attended the among marine taxa in the last 90 million UNESCO. Simultaneously the Paleogene meeting. Among the more outstanding years—sharp variations in the oxygen and Subcommission of the International problems that formed the focus of the carbon isotopic composition of uppermost Commission on Stratigraphy (ICS) desig- meeting were the following. Paleocene marine carbonates were identi- nated the Working Group on the Paleo- 1. Assessment of the newly revised fied. Late Paleocene–early Eocene varia- cene/Eocene Boundary to search for and chronology of the Paleogene, and in par- tions in the isotopic composition of provide documentation on stratigraphic ticular the Paleocene-Eocene boundary organic carbon of amplitude similar to sections that might serve as potential interval, with a view to unifying the dif- those described from marine carbonates standard bearers for the boundary between ferent geochronologies currently being have now been described from teeth of the Paleocene and Eocene series, the so- applied to this interval; determination of late Paleocene land mammals and from called Global Boundary Point and Section the chronologic position and sequence of upper Paleocene carbonate concretions in (GSSP) and its “golden spike.” In this the various events that have been found paleosols. In addition, marked sedimento- context, IGCP 308 has also been active in to be associated with this interval. logic features such as a decrease in grain seeking to provide the appropriate criteria 2. Review and synthesis of the major size of atmospheric dust and an increase by which the Paleocene-Eocene epoch climatic and biotic events that have been in kaolinitic content of marine deposits, in boundary may be characterized and the identified within the P-E boundary particular at high latitudes and on epicon- Paleocene-Eocene series boundary recog- interval in both marine and terrestrial tinental shelves, have been documented. nized and correlated. stratigraphies, including recent attempts These findings have led to the upper Pale- In view of the large database that at improved climate modeling of the P-E ocene–lower Eocene stratigraphic record has accumulated on the subject of the boundary interval. becoming the focus of considerable atten- P-E boundary interval, it was considered 3. Assessment of marine and terres- tion in earth science circles during the appropriate to convene an international trial stratigraphic correlations with a view past few years and to the recognition conference that would enable specialists that the latest Paleocene–earliest Eocene who have been engaged in IGCP Project Penrose Conference continued on p. 20

Environment continued from p. 18 inequity and environmental “injustice,” centration of working-class people of and it makes sense upon reflection. Some color—exactly the sorts of communities tance (to 1 mile) from TSDFs, while in- areas are too poor to have any economic that, in our area, organize and challenge dustrial use is highly significant regardless activity, including a TSDF, while others are the location of urban environmental haz- of distance; (4) per capita income first has wealthy enough to resist TSDFs being sited ards under the “environmental justice” a positive, then a negative effect on the nearby. The persistence of race across our concept. probability of TSDF location as income tests suggests that environmental justice The complete version of this study level rises. While the last finding may proponents have cause for their concerns, will appear in the December 1997 issue of seem anomalous to those who have at least in the Los Angeles area. The overall Social Science Quarterly; it is also available thought income, not race, is the driving pattern we find suggests that the commu- on the World Wide Web at http://www.oxy. force behind the location of environmen- nities most likely to “host” a TSDF are edu/academia/acadepts/environ.htm. ■ tal hazards, this relationship is consistent neighborhoods located near industrial with the assertion of demographic activity and with a large residential con-

GSA TODAY, August 1997 19 Penrose Conference continued from p. 19 PUBLICATIONS NEWS FROM the GSA to providing a rigorously tested and high- resolution chronologic framework for a historical geology of this important time in Earth history. Bookstore 4. Assessment of various bio-chemo- WATCH THIS COLUMN FOR NEWS ABOUT GSA PUBLICATIONS magnetostratigraphic events currently used and favored in depicting the P-E THE NATURE OF MAGMATISM IN THE APPALACHIAN Quaternary climates in the now-arid western North America series boundary with a view to establish- OROGEN led to a U.S. Geological Survey–funded core-drilling project on ing the main criterion (or criteria) to be edited by A. K. Sinha, J. B. Whalen and J. P. Hogan, 1997 Owens Lake, southeast California. The resulting 323-m-long used to define it when the GSSP is pro- The thermal evolution of mountain belts is commonly recorded core records lake fluctuations since 800 ka. This volume in the distribution, origin, and ages of magmatism. In this posed or selected. describes how they are revealed by variations in the CO3 and volume, 20 contributors present the latest petrological, isotopic, organic-C percentages, pore-water isotopic content, composi- 5. Review of local and regional and geochemical evidence to highlight the contribution of tion of clay-sized materials, magnetic susceptibility, and fossils stratigraphic studies in the classic areas igneous rocks to the evolution of the Appalachian orogen in (diatoms, ostracodes, mollusks, fish, and pollen). Sediment ages of northwestern Europe as well as the both Canada and the United States. These papers emphasize the are based on 14C data, measured mass-accumulation rates, and detailed studies that have been conducted use of modern geochemical and petrologic data to discriminate paleomagnetic variations. The recorded wet and dry climatic in specific areas with a view to providing the sources yielding magmas, and thus the nature of the crust cycles are about 100 ka long. Although their distribution in and mantle. The wealth of data available in this work provides a candidate sections for a suitable P-E GSSP time is similar to those of deep-sea and other records that significant stepping-stone to more rigorous interpretation of the largely reflect paleotemperatures, the maxima and minima of for selection by the voting members of the assembly and origin of the Appalachian orogen. the wet and dry cycles differ in age from correlative inflections Paleogene Subcommission and for recom- MWR191, 438 p., indexed, ISBN 0-8137-1191-6, $135.00, Member in paleotemperature records by an average of 15 ka. mendation to the International Union of price $108.00 SPE317, 172 p., indexed, ISBN 0-8137-2317-5, $60.00; Geological Sciences (IUGS). PHANEROZOIC FAUNAL & FLORAL REALMS OF THE Member price $48.00 Each day of the four-day meeting was EARTH: THE INTERCALARY RELATIONS OF THE MALVI- PERMIAN STRATIGRAPHY AND FUSULINIDA OF NOKAFFRIC AND GONDWANA FAUNAL REALMS WITH devoted to specific topics. AFGHANISTAN WITH THEIR PALEOGEOGRAPHIC AND THE TETHYAN FAUNAL REALM PALEOTECTONIC IMPLICATIONS by A. A. Meyerhoff and others, 1996 edited by E. Ja. Leven, C. H. Stevens, D. L. Baars, 1997 Day 1: Setting the Framework in MWR189, 78 p., hardbound, indexed, ISBN 0-8137-1189-4, An excellent overall study of the Permian Stratigraphy and Terms of Lyellian Stratigraphy $40.00; Member price $32.00 fusulinid faunas of Afghanistan. All of the major stratigraphic PLIOCENE CARBONATES AND RELATED FACIES sequences there are correlated with those of the adjacent W. A. Berggren reviewed the original FLANKING THE GULF OF CALIFORNIA, BAJA CALIFORNIA, Pamirs and are described, as are one new genus and 41 new definition and subsequent history of Pale- MEXICO species and subspecies of Permian fusulinid. ocene and lower Eocene (chrono)strati- edited by M. E. Johnson and J. Ledesma-Vázquez, 1997 SPE316, 138 p., ISBN 0-8137-2316-7, $45.00; Member price graphic units, recent modifications to The Gulf of California is a stimulating laboratory in which to $36.00 lithostratigraphic nomenclature in north- test the interplay between tectonics and eustasy with respect to THE THIRD HUTTON SYMPOSIUM ON THE ORIGIN OF the erosion of rocky shorelines. Not since GSA Memoir 43 on GRANITES AND RELATED ROCKS western Europe, and the implications of a the results of the 1940 E.W. Scripps Cruise to the Gulf of M. Brown, P. A. Candela, D. L. Peck, W. E. Stephens, R. J. Walker, revised (short) chronology for the north- California has there been assembled so expansive a collection of E-an Zen, 1996 western European P-E boundary interval research papers on the Gulf Coast Pliocene of Baja California. The invited papers in this volume, from the Third Hutton ash series (vs. the conventional “long” This volume takes up facies relations, paleogeography, and Symposium on the Origin of Granites and Related Rocks, chronology). He presented a relative tectonics where the classic exploration style of the 1950 Memoir summarize the latest ideas concerning crustal anatexis, melt segregation, magma transfer, and granite emplacement into chronology of the main events that span leaves off. The result of collaboration by Mexican and American geologists and marine biologists associated with the Sociedad lower- grade upper-crustal rocks. the 2 m.y. Paleocene-Eocene boundary Geológica Peninsular, the topics embraced by this well- SPE315, 225 p., indexed, ISBN 0-8137-2315-9, $78.00, interval. Until such time as a GSSP is integrated collection fall under three themes. One concerns the Member price $62.40 chosen, the P-E boundary is defined at origin of carbonate sediments, giving new emphasis to coralline the base of the Leper Clay Formation red algae as rhodoliths. Another deals with rocky shorelines as VISIT US ON THE WEB! (Belgium), stratigraphically equivalent to an ideal boundary marker for the mapping of facies and the GSA’s complete publications catalog is located at http://www.geosociety.org. the NP10a/b calcareous nannoplankton determination of relative sea-level changes. The third theme involves insights on Pliocene stratigraphy through Holocene boundary, within planktonic foraminiferal patterns of sedimentation and neotectonics. 1-800-472-1988 Zone P6b and with an estimated age of SPE318, 180 p., indexed, ISBN 0-8137-2318-3, $57.00, Member 54.37 Ma. price $45.60 GSA PUBLICATION SALES P.O. Box 9140, Boulder, CO 80301 Robert Knox reviewed the original AN 800,000-YEAR PALEOCLIMATIC RECORD FROM CORE OL-92, OWENS LAKE, SOUTHEAST CALIFORNIA (303) 447-2020 or fax 303-447-1133 stratigraphic units included in the lower Prepayment required. Major credit cards accepted. Eocene of England, emphasized Prest- edited by G. I. Smith, J. L. Bischoff, 1997 A need for more lacustrine records that document late wich’s (1854) remarkably precise stratigraphic cross section of the Thanet Sands and London Clay formations depicting the “surface of ravinement,” which corre- sponds precisely to the unconformable respectively. Organic carbon (pedogenic than the base of the Wasatchian (WaO) of sequence boundary separating the two nodules) have yielded a record in the Paris the Bighorn Basin. Cojan reviewed the units as recognized today. Knox continued Basin that appears to indicate a revised geologic setting and history of studies of with an overview of the modern (re)defini- scheme of correlation within the lacus- the Upper Cretaceous (Maestrichtian) and tion of stratigraphic units of the Lambeth trine-fluviatile (Sparnacian) formations Paleocene lacustrine sediments of the Aix- and Thames Groups, correlations with the of the Paris Basin and to allow, to a first en-Provence Basin. The ~350-m-thick sec- (subsurface) North Sea lithostratigraphic approximation, correlation with the ter- tion contains a record of several Paleocene units and sequences and causal connec- restrial record in North America (Wasat- magnetozones and of the long-term car- tions between observed faunal and floral chian land-mammal “age” [LMA] of the bon isotope trend seen in marine records. and lithic changes and atmospheric and Bighorn Basin) and the marine (deep sea) Unfortunately, a fault in the section ren- climatic events. record. A significant feature of this study ders it uncertain whether the “excursion” Medard Thiry and Isabelle Cojan pre- is the implication that the Conglomérat de seen in these records reflects the major sented overviews of the 13C stratigraphy Meudon (typical of the “Sparnacian” of of the Paris and Aix-en-Provence basins, northwestern Europe) is slightly younger Penrose Conference continued on p. 21

20 GSA TODAY, August 1997 Penrose Conference continued from p. 20 reactions between the ocean and terrestrial latitude (ODP Site 690) pelagic sections, biosphere via atmospheric CO2 are used that some Paleocene-Eocene NP (calcare- event recorded in marine and terrestrial by stratigraphers to predict what the pat- ous nannofossil) zones in the high south- records in Chron C24r elsewhere. tern of terrestrial carbon isotopic variabil- ern latitude sections may be time trans- Jan Hardenbol presented an overview ity should be relative to the marine carbo- gressive. He also presented new records and regional (Transatlantic) correlation nate record. The marine pelagic carbonate from new deep-sea sequences in the network (Gulf and Atlantic Coastal Plains, records show large changes indicating sub- Caribbean that contain laminated clay northwestern European basins) of the stantial reorganization of carbon between and volcanic ash at or near the boundary P-E boundary stratigraphic interval in a the major reservoirs during the late Pale- interval. These sequences provide impor- sequence stratigraphic framework and dis- ocene and early Eocene. These patterns of tant new insights into events near the cussed the recently completed Cenozoic change, including a marked negative car- boundary. In particular, the presence of a Global Sequence Stratigraphic Correlation bon isotope excursion near the P-E bound- distinct drop in CaCO3 percent during the Chart(s) prepared for inclusion in the ary are the focus of investigations that are excursion is consistent with a rapid shoal- forthcoming SEPM volume on sequence attempting to correlate terrestrial and ing of the ocean lysocline as predicted stratigraphy of European basins. marine sections across the P-E transition from the methane disassociation model of Marie-Pierre Aubry presented evi- interval. Sinha reviewed his own work in Dickens et al. (1996, 1997). Moreover, the dence for the incompleteness of strati- the Paris Basin and the London Basin, for availability of laminated sequences in the graphic records across the P-E boundary which there is now a detailed carbon iso- Caribbean sections, particularly those con- interval using an integrated magneto- tope stratigraphy from the pedogenic soils taining ash, should provide a very detailed bio- isotope-stratigraphic approach. She that characterize these classic sections. The high-resolution record of changes across emphasized that most stratigraphic sec- pattern of carbon isotope change recorded the interval, as well as a precise dating of tions only represent or record “windows in the pedogenic samples matches closely the event(s). Zachos also discussed the on time,” with overlap and exclusion of the model predicted values derived from high-resolution soil nodule carbon isotope temporal records from site to site, and dis- the marine carbonate records. This records of Koch et al. (1992, 1995) from cussed the need to conduct “temporal includes a distinct negative carbon the Bighorn Basin paleosol sequences, analysis of stratigraphic sections” to isotopic excursion near the base of the which show that the C-isotope excursion achieve sound temporal correlations Argiles Plastique of the Paris Basin and the and LPTM coincided with the earliest between sections. Reading Beds of the London Basin, an Eocene mammalian origination event. Will Clyde reviewed the magneto- excursion that correlates with the marked Doug Hammond reviewed models stratigraphy of the classic (most complete) marine carbonate excursion near the P-E that call on methane release from North American P-E terrestrial section, the boundary. clathrates to explain the large carbon Bighorn Basin. The Tiffanian-Wasatchian There are also notable points in the isotopic excursion near the P-E boundary. LMAs span the ~3 m.y. Chron C25n to terrestrial records where the terrestrial car- Other reservoirs containing isotopically C24n interval in a 2000+-m-thick strati- bon isotopic values are more positive than light carbon, such as the terrestrial bio- graphic record wih the 13C excursion iden- the model would predict. Sinha addressed sphere or the mantle are unlikely sources, tified at the base of the Wasatchian (WaO) several potential explanations for these given mass balance considerations. Ham- LMA approximately in mid–Chron C24r. anomalous values. Preservation is one pos- mond then presented model results in Several dubious or uncertain normal- sible explanation, but diagenesis would which the ODP Site 690 carbonate record polarity magnetozones in Chron C24r not likely produce temporally and spa- was used to model the dynamics of may correspond to the cryptochrons of tially consistent patterns throughout both methane cycling between the deep ocean, Cande and Kent (1995) and be suitable the Paris and London basins. Second, the the upper ocean, and the atmosphere. The for global correlation, but positive iden- incorporation of C4 plant material, which elimination of the surface-to-deep-water tification or correlation is not possible at is isotopically more positive than that of 13C gradient seen at this site during the present. the C3-type plants, is unlikely, because the excursion calls for rapid inputs of meth- Oral presentations were comple- majority of C4-type plants are thought to ane to the upper ocean and a reduction in mented by a poster dealing with the late have first appeared in the fossil record in oceanic mixing rates. The solid-gas phase Paleocene palynology of Siberia presented the Miocene. Sinha presented a third boundary at upper ocean pressures is near by Alina Yakovleva. intriguing possiblilty stemming from 12 °C. It is interesting that the excursion new experimental work. Using data from in the carbon isotope records coincided Day 2: Paleoceanography and growth experiments, he pointed out that with the warming of the deep sea to about Paleoclimatology of the P-E carbon isotope fractionation in C3 plants 12 °C and may help explain why there was Boundary is related to CO2 concentrations in the apparently a sudden release of methane at atmosphere. The experimental work indi- that particular time. Lowell Stott opened the morning ses- cates that there is a systematic increase Karen Bice reviewed the status of gen- sion with a review of carbon and oxygen in the fractionation of 13C and 12C with eral circulation modeling of the boundary isotopic changes recorded through the increasing CO concentrations. The anom- interval. There remain several problems mid-Paleocene to lower Eocene marine 2 olously low 13C values in the Paris and in model-data comparisons. These include records. He pointed out that the distinct London basins could, therefore, point to the underestimation of high-latitude sea- isotopic events documented near the Pale- relatively lower pCO levels in the earliest surface and bottom-water temperatures, ocene-Eocene boundary are superimposed 2 Eocene. even given atmospheric carbon dioxide on long-term changes in the temperature James Zachos discussed the pattern of and oceanic heat transport values elevated of the ocean and long-term changes in carbon isotope change recorded in several relative to the modern values. Ocean sim- their carbon isotopic composition. Even marine and terrestrial sections and their ulations indicate that the modeled ther- though the cause(s) of these changes are implications for (1) chemostratigraphy mohaline circulation is dependent on not known, they provide the backdrop for and stratigraphic completeness, and ocean geometry and freshwater fluxes to the events near the boundary. (2) testing models of the LPTM (late Pale- the sites of potential deep-water forma- Ashish Sinha reviewed the systematics ocene thermal maximum) event. In partic- tion. For the early Eocene, these include of carbon isotope exchange reactions ular, he raised the possibility, based on a the Northern Tethyan margin and the between the major carbon reservoirs. comparison of carbon isotope records The equilibrium carbon isotope exchange from tropical (ODP Site 865) and high- Penrose Conference continued on p. 22

GSA TODAY, August 1997 21 Penrose Conference continued from p. 21 Thierry Adatte discussed the paleo- netics is low for many marine sequences, climatic, oceanographic, and ecologic and at a few sites there appear to be prob- circum-Antarctic ocean. A minor North changes associated with P-E boundary lems with biostratigraphic datums (relative Atlantic deep-water source is possible, events as recorded in the deep Tethyan to magnetochrons). In particular, there are especially for the intervals during which basin. He presented lithologic, clay assem- significant inconsistencies at ODP Site the North Sea basin was flooded. The pre- blage, and stable isotopic data from several 690B. The best marine magnetostrati- diction of a warm, saline deep-water marine sequences, including the Spanish graphic sequences appear to be Contessa source in the Northern Tethys is depen- sections Zumaya, Caravaca, and Alade- Road and ODP Site 752, while ODP Site dent on the treatment of continental milla. In general, all sites show the C-iso- 690 and DSDP Site 577 may provide runoff in the model. tope excursion and REE. Several of the important additional data. Steven Schel- Paul Koch presented a model for the sites show pronounced increases in phyl- lenberg outlined a research project application of soil iron-oxide oxygen iso- losilicate clay content, primarily kaolinite, designed to quantify variations in P-E tope ratios to reconstruct terrestrial tem- coincident with the excursion. The bottom-water paleotemperature. Current perature variations across the P-E bound- increase in kaolinite is often accompanied estimates based on oxygen isotopes may ary. According to Koch, the composition by a relative decline in smectite. At Alade- contain small errors due to salinity (ice- of the soil Fe oxides (hematite) is deter- milla, the clay transition is marked by an volume) effects. Schellenberg intends to mined primarily by the δ18O composition increase in palygorskite. The kaolonite is use an independent proxy, the Mg/Ca of the soil (meteoric) water in which it thought to reflect an increase in humidity ratios of deep-sea ostracodes, to recon- forms with a small temperature-dependent and chemical weathering, and the paly- struct bottom-water temperature. If suc- fractionation. Since the composition of gorskite is interpreted as an indicator of cessful, this procedure would also allow meteoric water varies primarily as a func- more arid conditions. him to deconvolute the ice-volume contri- tion of surface temperature, the oxide δ18O Wilfried Winkler spoke on the sedi- bution to the oxygen isotope record. composition can be used to estimate past mentary and climatic aspects of the late changes in temperature. The primary ad- Paleocene–early Eocene in northern Spain. Day 3: Biotic Events across the vantage of Fe oxides is that they are highly The climatic reconstructions were based P-E Boundary Interval resistant to diagenesis, unlike calcite and on detailed sedimentologic, clay assem- The third day focused on biotic other geologic materials. To demonstrate blage, and bulk-rock stable isotope time events across the P-E transition. The 13 the feasibility of this approach, Koch pre- series from Zumaya. One of the more talks were divided into seven on terrestrial sented preliminary data for samples col- prominent features of this record is a large mammals, two on paleoflora, three on lected from the upper Paleocene–lower increase in the relative concentration of foraminifera, and one on calcareous Eocene paleosol sequences of the Bighorn kaolinite coincident with the C-isotope nannoplankton. Two posters were also Basin. These preliminary data indicate a excursion and REE. According to Winkler, presented, one on mammals and one on large depletion in δ18O values in the early this depositional event reflects a signifi- nonmarine gastropods. Eocene following the WaO interval. cant increase in precipitation and chemi- The talks on mammals concentrated Although such a trend might be caused cal weathering. This event was accompa- on the Holarctic continents—Europe, Asia, by changes in more than one factor, Koch nied by a large reduction in regional and North America—which formed a sin- showed that one possible interpretation, productivity. gle paleobiogeographic province during that there was a significant decline (~4 °C) Birger Schmitz presented new isotope the P-E transition. A significant reorgani- in MAT following the LPTM event, is con- and trace element data from three shallow zation of the placental mammalian fauna sistent with previous findings based on an marine Tethyan sequences, Ben Gurion, took place during the P-E transition and independent proxy (paleobotanical) of Gebel Duwi, and Gebel Aweina, Egypt. marks the beginning of the Wasatchian MAT for this region. The lithology and geochemistry of the land-mammal “age” (LMA) in North Tim Bralower presented new data sediments indicate that deposition in this America and the beginning of the Neus- from two recently drilled Caribbean cores, region was strongly influenced by local trian (=“Sparnacian”) LMA in Europe. This ODP sites 999 and 1001, each of which coastal upwelling. A C-isotope excursion reorganization includes the first appear- contains an expanded sedimentary record of between –3‰ and –4‰ is recorded at ance of perissodactyls, artiodactyls, and of the LPTM event. Preliminary lithologic each section. In addition, there is evidence euprimates in North America, and of these and geochemical records from these sites of increased productivity at the P-E groups as well as rodents, carnivores, and show evidence of environmental changes boundary interval. The most dramatic bats in western Europe. In North America, including dysoxic bottom-water condi- change occurs at G. Duwi where barium this reorganization (also called the “mam- tions and minor warming of surface wa- accumulation rates increase severalfold malian origination event” or MOE) is best ters. The most prominent feature, how- within the excursion interval. According recorded in the Bighorn Basin of Wyo- ever, is the presence of multiple ash layers, to Schmitz, this change reflects a funda- ming, which preserves the most complete including one at the onset of the LPTM mental shift in the intensity of the trade terrestrial record of the P-E transition. warming episode in both cores. These winds at this time. In addition, at G. Duwi Philip Gingerich reviewed that record, ashes provide compelling evidence that the change in productivity appears to be emphasizing the distinctiveness of the volcanism may have directly influenced permanent. oldest Wasatchian mammalian fauna climate change. According to Bralower, John Flynn and Lisa Tauxe presented (Wa0 Zone) from earlier Clarkforkian these Caribbean eruptions may have trig- a talk analyzing all the principal magne- mammal faunas. He suggested that the gered the LPTM event by causing high- tostratigraphic data sets from both marine LPTM allowed boreal dispersal of Holarctic latitude warming on millennial time scales and terrestrial strata spanning the P-E mammals leading to the MOE. Opening via carbon dioxide emissions, and shorter boundary interval, and applied two mea- of the North Atlantic during Wa1 time led term tropical and subtropical cooling via sures to assess reliability. The P-E bound- to increasing endemism and divergence sulfur dioxide emissions. This combina- ary (under any of the potential defini- of the North American and Eurasian mam- tion of climatic effects led to an abrupt tional criteria) lies within Chron C24r. mal faunas. (Several mammalogists pre- shift in the source of intermediate waters The most robust terrestrial magnetostratig- sent at the conference informally agreed to low-latitude regions. The flow of warm- raphies come from the northern Bighorn that the mammal event should be called er waters to intermediate depths, in turn, Basin, Ellesmere Island, and the San Juan a “mammal dispersal event” rather than triggered the dissociation of methane Basin. There is poor consistency among a “mammal origination event” in view of hydrates in continental-rise sediments. ODP and DSDP sites, reliability of the mag-

22 GSA TODAY, August 1997 the evidence and of known processes of in Mexico, Wyoming, and Arctic Canada. somewhat after it. However, the big diver- mammal evolution.) Joe Hartman’s poster documented the sity changes in planktonic foraminiferans Spencer Lucas presented a compre- stratigraphic distribution of extensive took place later, during late Biochron hensive correlation of Holarctic mammals assemblages of land snails in the western NP12 and at the P10/P11 biochronal of the P-E transition. He equated the MOE United States, identifying significant boundary. at the beginning of Wasatchian and Neus- turnover events that provide biostrati- Clay Kelly also looked at ODP site trian time and emphasized that it predates graphic datums for correlation. 865 using high-resolution sampling of the the beginning of the Ypresian Stage Scott Wing presented a broad 5-m-thick interval around the C-isotope (= base of Leper Clay in Belgium), which overview of Holarctic paleofloras of the excursion. He identified a short-lived bot- currently defines the base of the Eocene. P-E transition. He distinguished a fairly tleneck in the evolution of Morozovella The MOE correlates closely, though per- homogeneous, widespread Paleocene flora velascoensis, possibly caused by a deepen- haps not exactly, to the C-isotope excur- dominated by temperate, deciduous lin- ing of the mixed layer and intensification sion. The mammalian turnover at the eages from early Eocene floras dominated of oligotrophy. beginning of the Bumbanian LMA in Asia by legumes and other subtropical and Marie-Pierre Aubry identified a pro- may, however, postdate the MOE as indi- tropical species. The Bighorn Basin pale- found turnover in calcareous nannoplank- cated by close-correlation using species of ofloras do not indicate a major floral ton during the P-E transition comparable the pantodont Coryphodon. turnover at the Clarkforkian-Wasatchian to the turnover at the Cretaceous-Paleo- Jerry Hooker divided the Neustrian boundary, although diversity did drop gene boundary. On the basis of the genus LMA in Europe into zones and attempted somewhat at that boundary and there as the operational taxonomic unit, she to correlate these zones precisely to inter- were significant floral shifts during identified three bursts of evolution in the vals of the North American Wasatchian warming periods of the Wasatchian. calcareous nannoplankton—earliest Pale- LMA. He argued that the MOE in Europe Peter Wilf focused on late Paleocene ocene, early late Paleocene and during the was a more profound reorganization than floras from the Rock Springs uplift of P-E transition. Dominant Paleocene forms in North America, and that most of the southwestern Wyoming, which, on the became extinct during the transition, and Neustrian first appearances were immi- basis of leaf-margin analysis, suggest a numerous new genera appeared within a 1 grants from North America. mean annual temperature of 16 °C. m.y. interval from mid–Biochron NP9 to Marc Godinot discussed the P-E He noted the strong present correlation the NP10a/b biochronal boundary. transition mammalian assemblages from between leaf size and rainfall and used southern France, Spain, and Portugal. that relation to estimate rainfall of 1.1 to Day 4: Special Studies on Potential On the basis of their stage of evolution, 1.8 m/yr in southwestern Wyoming dur- P-E Boundary GSSPs he argued that these mammals predate the ing the late Paleocene. ICS regulations require that GSSPs beginning of the Neustrian and represent Ellen Thomas stressed the unusual be defined on land-based marine sections. an endemic, Tethyan center of origin. He nature of the extinction of benthic Thus, shallow marine to bathyal sections thus argued, contra earlier speakers, for a foraminifera that correlates closely to located in different countries have been strong immigration of mammals from the C-isotope excursion. She linked the studied with the goal of finding the Europe to North America during the P-E extinction to an overall drop in oceanic “ideal” GSSP for the P-E boundary. As transition. productivity (increased oligotrophy) but our work progressed, however, we became Suyin Ting reviewed the Asian mam- pointed out that there are different post- aware that the concept of an “ideal sec- mal record of the P-E transition, recogniz- extinction patterns in different places, tion” is rather utopian. At the same time, ing three LMAs (ascending): Nonshangian, suggesting a complex event. In general, we understood that what matters is not so Gashatan, Bumbanian. She correlated after the excursion the benthic forami- much to find the GSSP, but to determine the beginning of the Bumbanian and niferal fauna was dominated by a few, how sections in different geologic and tec- Wasatchian-Neustrian and emphasized thin-walled species. tonic settings correlate with one another. the contrasting endemism of Nonshang- Richard Norris noted that global com- Thus, following an introduction by ian mammals and cosmopolitanism of pilations of planktonic foraminiferal diver- Hanspeter Luterbacher regarding the Gashatan and Bumbanian mammals. sity show little change associated with the ICS guidelines for the definition of a GSSP, Will Clyde used the Bighorn Basin C-isotope excursion. Examination of the the morning session was devoted to the mammal record to delineate how taxo- foraminiferal record at ODP site 865 in the stratigraphic analysis of upper Paleocene– nomic turnover at the beginning of the central Pacific indicates that subbotinids lower Eocene sections concurrently stud- Wasatchian LMA affected mammalian were stable through the excursion (they community composition. Overall diversity were thermoclinal species), whereas increased at the beginning of the acarininids and morozovellids diversified Penrose Conference continued on p. 24 Wasatchian, largely due to extensive immigration of herbivores, carnivores, and frugivores into the Bighorn Basin. The immigrants continued to diversify through the Wasatchian, during which mammalian species richness was more At its May meeting, the GSA Council granted full evenly distributed. Member privileges to Teacher Associates, including Teacher Chris Beard reviewed the early the right to hold office and the right to vote. For Associates Wasatchian mammals from the Tusca- this reason, Teacher Associates will now be named homa Formation in Mississippi which Teacher Members, effective immediately. Renamed provide a direct nonmarine-marine cross- correlation to nannoplankton Zone NP9. Teacher Members will receive a 1997 Corporate Teacher Members Judith Schiebout’s poster focused on the Ballot and the Society encourages them to mammalian succession of the P-E transition in Big Bend National Park, Texas, vote for 1998 Officer and Councilor which has a magnetostratigraphy that cor- candidates. relates the beginning of the Wasatchian to Chron 24r, as is the case in other sections

GSA TODAY, August 1997 23 Penrose Conference continued from p. 23 on bulk samples. Only one section yielded boundary based on a presentation by good biostratigraphic results, providing Marie-Pierre Aubry of the pros and cons ied by different groups of IGCP Project rare direct correlation between calcareous of the seven criteria that are worth consid- 308. (calcareous nannofossils and planktonic ering (from younger to older: FAD T. digi- Birger Schmitz primarily discussed foraminifera) and siliceous (radiolarian) talis; LAD M. velascoensis; FAD T. bramlettei; the carbon isotopic record in sections microfossils. These results were further benthic foraminiferal extinction; carbon from Egypt, Israel, Spain, and Austria, documented by Fluegeman in a poster. isotope excursion; Chron C245n/C24r emphasizing the interval in which the Christian Dupuis discussed sequence magnetic reversal boundary; top of the carbon isotope excursion occurs. He stratigraphic subdivision of sections near Thanet Beds). The use of the FAD of Tri- showed that the expanse of the interval Tunis, and attempted correlation with brachiatus digitalis, which approximately in which the excursion occurs varies sections located in the western part of the dates the base of the Ypresian Stage would between sections, independently of their Paris Basin along the coast of Normandie- result in stable stratigraphic nomenclature completeness. Thus, some sections are def- Picardie. He showed that whereas there as emphasized in the guidelines by Hed- initely better suited as a GSSP than others seems to be clear correlation between berg. The C-isotope excursion is seen as if the excursion is used to characterize the some sequence boundaries, others are the best criterion for correlation because boundary. The Awaina section in the Nile present only in the Paris Basin. it has been identified in the terrestrial as Valley (near Luxor, Egypt) is currently seen Marie-Pierre Bolle and colleagues well as in the marine record. It also corre- as the best section to serve as a GSSP, but discussed the suitability of the Ermua and lates with the benthic foraminiferal the unstable political situation there is Trabakua sections in northern Spain as extinction event recorded in the bathyal preventing an official proposal. GSSPs. These have been officially proposed and abyssal realms. If the C-isotope Ernie Mancini and Nick Tew de- by Spanish colleagues as boundary strato- excursion is selected to recognize the P-E scribed the Tuscahoma and Bashi forma- types. On sedimentologic grounds, Bolle boundary worldwide, the boundary would tions in terms of sequence stratigraphy. and co-workers indicated that other Span- be placed at the sharp mammalian turn- These are siliciclastic deposits that repre- ish sections would constitute more appro- over (the MOE) that occurred between the sent a span of ~7 m.y. The section that priate GSSPs, a proposition that was fur- Clarforkian and Wasatchian (North Amer- best illustrates the Tuscahoma-Bashi con- ther documented in a poster. ica) and Cernaysian-Neustrian (Europe) tact is currently inaccessible except by Laurel Bybell gave a short explana- ages. boat or helicopter. The lowstand sands at tion, complemented with a poster, of the Discussion centered on the part of the contact between the two formations differences in taxonomic concepts which the excursion that should be chosen to is, however, seen at the Red Hot Truck lead to disagreements between authors delineate the boundary and the possible Stop, where a land-mammal fauna was about the location of the NP9/NP10 zonal pitfalls in the procedure. A paper by Ger- discovered (discussed by Chris Beard; see boundary. This continuing debate is ald Dickens emphasized that there was Day 3). relevant to the relation between the as yet no demonstration that methane Tom Gibson discussed the upper NP9/NP10 zonal boundary and the degassing through clathrate dissociation Paleocene (Vincentown Formation)–lower C-isotope excursion. occurred (the best possible evidence being Eocene (Manasquan Formation) record of In a poster session, Piotr Gawenda the excursion itself) and warned that dis- the east Atlantic coast (New Jersey), which and Wilfried Winkler presented evidence sociation would have occurred at different he believes to be continuous across the for tectonic complications at the P-E times in different locations. However, geo- P-E boundary. Using tau values on benthic boundary in the Zumaya section (Spain); chemists at the conference remarked that foraminifera, he discussed regional paleo- Eustoquio Molina presented correlations diachrony would be on the order of a few depth changes. between the main Spanish sections; thousand years at most. Also, Doug Ham- Richard Fluegeman presented the Simonetta Monechi documented the mond gave a presentation on carbonate results of biostratigraphic studies of several calcareous nannofossil stratigraphy of dissolution and reminded us that lack of sections in Cuba collected in 1993 by an Spanish sections, and Katharina Perch- carbonates (as in most Spanish sections) international field party. The collecting Nielsen presented that of sections in does not necessarily imply dissolution. was aimed at integrated magneto-bio- Egypt. The conference ended with a full isotopic analyses. The rock quickly proved The afternoon session resumed with appreciation that reconstructing the to be unsuitable for magnetostratigraphy, a discussion on the best criteria to use to geological history of even as short a time and chemostratigraphy was possible only characterize the Paleocene-Eocene Epoch interval as that of Chron C24r (~2.55 m.y.) requires a multidisciplinary approach and the study of many different sections around the world. As geologists, we have Penrose Conference Participants a tendency to look for the “best section,” but we are beginning to understand that Thierry Adatte Marc Godinot Richard D. Norris any section, how unpromising it may Chris Beard Doug Hammond Frederic Quillevere look, contributes some of the evidence Karen L. Bice Jan Hardenbol Stephen Schellenberg that contributes to the whole story. We Marie Pierre Bolle Joseph H. Hartman Judith A. Schiebout believe that this conference gave all a bet- Timothy Bralower J. J. Hooker Birger Schmitz ter respect for the complexity of the strati- Laura Bybell Brian T. Huber Ashish Sinha graphic record. Charles Chapin Alina Iakovleva Berry H. (Nick) Tew William C. Clyde H. Jochen-Kuss Medard Thiry Rodolfo Coccioni Daniel Clay Kelly Deborah J. Thomas ACKNOWLEDGMENT Isabelle Cojan Adrian King Ellen Thomas We thank Lois Elms (Western Experi- Christian Dupuis Robert Knox Suyin Ting ence, Inc., and long-standing coordinator Gae Eisenhardt Paul Koch Katharina von Salis of GSA-sponsored Penrose Conferences) John W. Estep Hanspeter P. Luterbacher Peter Wilf for arranging the logistics of this Rick Fluegeman Ernest A. Mancini Scott Wing ■ John Flynn Simonetta Monechi Wilfried Winkler meeting. Tom Gibson Thierry L. A. Moorkens Thomas E. Yancey Phillip Gingerich Hiroshi Nishi

24 GSA TODAY, August 1997 edited by Markes E. Johnson and Jorge Ledesma- Vázquez, 1997 The Gulf of California is a stimulating laboratory in which to test the interplay between tectonics and eustasy with respect to the erosion of rocky shorelines. Not since GSA Memoir 43 on the results of the 1940 E.W. Scripps Cruise to the Gulf of California has there been assembled so expansive a collection of research papers on the Gulf Coast Pliocene of Baja California. This volume takes up facies relations, paleogeography, and tectonics where the classic exploration style of the 1950 Memoir leaves off. The result of collaboration by Mexican and American geologists and marine biologists associated with the Sociedad Geológica Peninsular, the topics embraced by this well- integrated collection fall under three themes. One concerns the origin of carbonate sediments, giving new emphasis to coralline red algae as rhodoliths. Another deals with rocky shorelines as an ideal boundary marker for the mapping of facies and the determination of relative sea-level changes. The third theme involves insights on Pliocene stratigraphy through Holocene patterns of sedimentation and neotectonics. SPE318, 180 p., indexed, ISBN 0-8137-2318-3, $57.00, Member price $45.60

Volumes are 8-1/2" x 11" paperback. Prices include shipping and handling.

Publication Sales • P.O. Box 9140 • Boulder, CO 80301 • 303-447-2020 • fax 303-447-1133 • www.geosociety.org 1-800-472-19881-800-472-1988

GSA TODAY, August 1997 25 Penrose Conference To Address Evolution of Ocean Island Volcanoes

A Geological Society of America petrologically, geochemically, Penrose Conference, “Evolution of Ocean and tectonically? Island Volcanoes,” will be held June 4–12, • What are the common and unique 1998, in the Galápagos Islands, Ecuador. patterns at different volcanoes? The Charles Darwin Foundation and IAV- • How do the different styles of evolu- CEI are cosponsors. tion relate to differences in tectonic Volcanism associated with ocean setting, ocean basins, sources, and islands changes in several ways with time. strengths of the hotspots? In most archipelagos, the eruptive styles of • How does the evolution of ocean island individual volcanoes vary temporally, giv- volcanoes help constrain models of the ing rise to different types of deposits as the deep earth (e.g., mantle plumes)? of volcano emerges above the sea, reaches a • Are there alternatives to the mantle how peak in activity, and dies. At most volca- plume theory that better explain ocean oceanic noes, the variation in eruptive style is island volcanism? volcanoes accompanied by systematic changes in the change with time. petrologic, trace element, and isotopic LOCATION Owing to the field-intensive aspect of compositions of the magmas. These this Penrose Conference, participants must The conference will be held in the changes at individual archipelagos lend be reasonably fit (able to walk 2 miles and Galápagos Islands, Ecuador, a locale virtu- critical insight into geodynamic processes ascend 1000 feet in the sun) and tolerant ally synonymous with evolution. Partici- such as the interaction between mantle of equatorial heat. The conference facili- pants will depart Quito, Ecuador, on plumes and their surroundings, the ties have no air conditioning. The boat June 4, 1998, and fly to San Cristobal amount and rate of melt production, and and hotel facilities are superb yet informal. Island, where they will be picked up by the degree of chemical heterogeneity of the tourist ships Corinthian and San Jac- the mantle source. Despite their common LOGISTICS into. For the first five days of the confer- characteristics, different archipelagos dis- ence, we will be touring from these boats, The conference will be limited to 60 play utterly distinct evolutionary styles, examining Galápagos volcanoes in various participants, who will be selected to repre- which suggests that differences in tectonic stages of evolution; talks and discussion sent a broad range of disciplines and with setting or plume dynamism, or both, can sessions will occupy mornings and eve- knowledge of diverse geologic settings. We lead to variations in the evolutionary nings. The preliminary itinerary for the will be able to subsidize travel for several development of individual ocean islands. field trip will take the conference from the strongly qualified graduate students. The oldest part of the archipelago (San Cristo- registration fee, which will cover boat PURPOSE bal and Espanola islands) to active volca- travel, lodging in Puerto Ayora, and meals The purpose of the conference is to noes (Sierra Negra and Santiago). There exclusive of dinners in Puerto Ayora, is convene a broad spectrum of specialists will be abundant opportunity to observe expected to be about $1180. We expect who have worked on different aspects of and photograph the wildlife for which the group airline fares to be available from many different islands to compare com- archipelago is renowned. On June 8, the Miami for approximately $750. mon patterns, highlight unique styles of participants will disembark to Puerto evolutionary change, and assess models Ayora, Santa Cruz Island, home of the CONVENERS for the causes of the patterns of evolution- host institution, the Charles Darwin Co-conveners are Dennis Geist, ary change. The major questions to be Research Station. Three days of oral pre- Dept. of Geology, University of Idaho, addressed by the conference are: sentations, poster sessions, and discussions Moscow, ID 83844, [email protected], • How do different volcanoes in different will focus on current research and future fax 208-885-5724, phone (208) 885-6491; island chains evolve volcanologically, directions that will lead to holistic models Karen Harpp, Dept. of Chemistry, Lawrence University, Appleton, WI 54912, [email protected], fax 414- 832-6962, phone 414-832-6729; Wendy Bohrson, Dept. Geological Sciences, University of California, Santa Barbara, Penrose Conference CA 93106, [email protected], fax 805-893-2314, phone (805) 893-8782. Proposals Encouraged E-mail inquiries are preferred by all of the co-conveners. The Penrose Conferences, named in honor of R. A. F. Penrose, Jr., a benefactor of the Geological Society of America, were established in 1969 by the Society as a further step in DEADLINE its service to the science of geology. The conferences provide the opportunity for exchange of current information and exciting ideas pertaining to the science of geology and related Application deadline is January 15, fields. They are intended to stimulate and enhance individual and collaborative research and 1998. Formal invitations will be mailed by to accelerate the advance of the science by the interactions and development of new ideas. February 15, 1998. Three paper copies of applications, sent to Dennis Geist, should l include a brief curriculum vitae (e.g., NSF form 1362), a cover letter indicating your For Guidelines Contact GSA Headquarters interest and experience, and the subject of (303) 447-2020, ext. 131 • fax 303-447-1133 • [email protected] proposed poster presentations. ■

26 GSA TODAY, August 1997 VOLUME 25 August BULLETIN and NO. 8 P. 673Ð768 GEOLOGY Contents AUGUST 1997 675 Carboniferous age for the East Greenland “Devonian” basin: Paleomagnetic and isotopic constraints on age, stratigraphy, and The Geological Society of America plate reconstructions E. H. Hartz, T. H. Torsvik, A. Andresen 679 Earthquake clustering inferred from Pliocene Gilbert-type fan deltas in the Loreto basin, Baja California Sur, Mexico Volume 109, Number 8, August 1997 Rebecca J. Dorsey, Paul J. Umhoefer, Peter D. Falk 683 Benthic foraminiferal extinction and repopulation in response to CONTENTS latest Paleocene Tethyan anoxia Robert P. Speijer, Birger Schmitz, Gijsbert J. van der Zwaan 915Ð935 Structural and sedimentological development of footwall growth 687 Recognition of units in coarse, unconsolidated braided-stream de- synclines along an intraforeland uplift, east-central Bighorn posits from geophysical log data with principal components analysis Mountains, Wyoming Warren Barrash, Roger H. Morin Richard G. Hoy and Kenneth D. Ridgway 691 Isotope data from Cretaceous chalks and foraminifera: Environmental or diagenetic signals? 936Ð954 OVERVIEW: Tectonic implications of Cenozoic volcanism in Simon F. Mitchell, James D. Ball, Stephen F. Crowley, Jim S. Marshall, coastal California Christopher R. C. Paul, Cornelis J. Veltkamp, Ashraf Samir William R. Dickinson 695 Microtopography as an indicator of modern hillslope diffusivity in arid terrain 955Ð977 Foreland crustal structure of the New York recess, northeastern R. Jyotsna, P. K. Haff United States 699 Anomalously cold temperatures observed at the base of the gas Gregory C. Herman, Donald H. Monteverde, Roy W. Schlische, and hydrate stability zone on the U.S. Atlantic passive margin David M. Pitcher Carolyn Ruppel 703 Magellan Strait: Part of a Neogene rift system 978Ð999 Sequence stratigraphy of sixth-order (41 k.y.) PlioceneÐPleistocene Marc Diraison, Peter R. Cobbold, Denis Gapais, Eduardo A. Rossello cyclothems, Wanganui basin, New Zealand: A case for the regressive 707 Seismic reflections from subvertical diabase dikes in an Archean terrane systems tract Eva Zaleski, David W. Eaton, Bernd Milkereit, Brian Roberts, Matthew Salisbury, Tim Naish and Peter J. J. Kamp Larry Petrie 711 Cooling of an igneous dike 20 yr after intrusion 1000Ð1020 Emplacement and reworking of Cretaceous, diamond-bearing, crater C. B. Connor, P. C. Lichtner, F. M. Conway, B. E. Hill, A. A. Ovsyannikov, facies kimberlite of central Saskatchewan, Canada I. Federchenko, Yu. Doubik, V. N. Shapar, Yu. A. Taran Dale A. Leckie, B. A. Kjarsgaard, John Bloch, David McIntyre, 715 Evidence for thermohaline-circulation reversals controlled by sea-level David McNeil, Laverne Stasiuk, and Larry Heaman change in the latest Cretaceous Enriqueta Barrera, Samuel M. Savin, Ellen Thomas, Charles E. Jones 1021Ð1035 Transfer of displacement from multiple slip zones to a major detach- 719 Did the Indo-Asian collision alone create the Tibetan plateau? ment in an extensional regime: Example from the Dead Sea rift, Israel M. A. Murphy, An Yin, T. M. Harrison, S. B. Dürr, Chen Z., F. J. Ryerson, Michael R. Gross, Alexander Becker, and Gabriel Gutiérrez-Alonso W. S. F. Kidd, Wang X., Zhou X. 723 Diapirism initiated by the Bushveld Complex, South Africa 1036Ð1054 Igneous evolution of a complex laccolith-caldera, the Solitario, Ronald Uken, Michael K. Watkeys Trans-Pecos Texas: Implications for calderas and subjacent plutons 727 Opening of the central Atlantic and asymmetric mantle upwelling Christopher D. Henry, Michael J. Kunk, William R. Muehlberger, and phenomena: Implications for long-lived magmatism in western W. C. McIntosh North Africa and Europe Roberto Oyarzun, Miguel Doblas, José López-Ruiz, José María Cebriá Hydrodynamic strategies in the morphological evolution of spinose 1055Ð1072 731 Morokweng, South Africa: A large impact structure of Jurassic- planktonic foraminifera Cretaceous boundary age David Jon Furbish and Anthony J. Arnold Christian Koeberl, Richard A. Armstrong, Wolf Uwe Reimold 735 Cenozoic subsidence and uplift of continents from time-varying dynamic topography C. Lithgow-Bertelloni, Michael Gurnis 739 Influence of subglacial drainage conditions on the velocity distribution within a glacier cross section MOVING? Don’t risk missing a single issue of Jon Harbor, Martin Sharp, Luke Copland, Bryn Hubbard, Peter Nienow, Douglas Mair GSA Today! If you’re planning on changing your 743 Generation of metaluminous A-type granites by low-pressure melting address, simply write in your new address and mail of calc-alkaline granitoids this coupon along with your subscription mailing Alberto E. Patiño Douce label (use label from this newsletter) to: GSA, Mem- 747 Early Paleozoic paleogeography of Laurentia and western Gondwana: bership Services, P.O. Box 9140, Boulder, CO Evidence from tectonic subsidence analysis Kenneth E. Williams 80301-9140. Or you may call with your change of address information— (303) 447-2020 or 1-800-472-1988 or E-mail us at mem- 751 Alpine and pre-Alpine subduction events in polycyclic basements of the Swiss Alps [email protected]. G. G. Biino, D. Marquer, Ch. Nussbaum (Report address changes at least six weeks in advance. If possible, give us your 755 Divergent double subduction: Tectonic and petrologic consequences change of address by the tenth of the month.) Alvar Soesoo, Paul D. Bons, David R. Gray, David A. Foster PLEASE PRINT 759 Ejecta layer at the Cretaceous-Tertiary boundary, Bass River, New Jersey (Ocean Drilling Program Leg 174AX) Richard K. Olsson, Kenneth G. Miller, James V. Browning, Daniel Habib, Name ______Peter J. Sugarman Address ______Forum 763 Mantle underplating, granite tectonics, and metamorphic P-T-t paths ______Comment: C. K. Mawer, J. D. Clemens, N. Petford Reply: Rosalyn G. Warren, David J. Ellis City ______765 40Ar/39Ar laser probe dating of detrital white micas from Cretaceous sedimentary rocks of the Eastern Alps: Evidence for Variscan high- State/ZIP/Country ______pressure metamorphism and implications for Alpine orogeny Comment: Wilfried Winkler, Daniel Bernoulli, Giorgio V. Dal Piaz, Silvana Martin Reply: Hilmar von Eynatten, Reinhard Gaupp, Jan R. Wijbrans Phone (business hours) ______767 Long-term faunal stasis without evolutionary coordination: Jurassic benthic marine paleocommunities, Western Interior, I do not wish to have this number in the Membership Directory. United States: Reply: Correction 767 Sizing Information for Geology Manuscripts Change my voting section to: ______768 Guidelines for Geology Authors

GSA TODAY, August 1997 27 GSA ANNUAL MEETINGS

1997 Salt Lake City, Utah ◆ October 20–23 Salt Palace Convention Center ◆ Little America Hotel

Call for Papers: April and June GSA Today Register Preregistration Deadline: September 19 Today!

Technical Program Schedule: September GSA Today and the Web

Registration and Housing information: June GSA Today.

Announcing … For Information on any GSA Meeting 1-800-472-1988 or Late-Breaking Research Sessions (303) 447-2020, ext. 133 E-Mail: [email protected] for Salt Lake City 1997 GSA Annual Meeting WWW:http://www.geosociety.org October 20–23, 1997, Salt Palace Convention Center Exciting new data or breakthroughs over the summer? Present your work at the GSA Annual Meeting this fall! Visit Us! Special instructions for submitting an abstract for the Late-Breaking Research Sessions: ◆ An abstract on late-breaking research may be submitted after September 1 until GSA Headquarters midnight, September 30, 1997. ◆ Abstracts must be submitted using the Web form; they may not be submitted on Services Area paper or by e-mail: http://www.geosociety.org. ◆ Space will be limited and selection will be based on scientific merit. ◆ The author will be asked to provide a brief explanation of why the abstract in addition to the regular deserves consideration after the usual deadline for this meeting. exhibit hours, the Services ◆ The author may designate either oral and/or poster, although space limitations area will be open again on may require reclassification. ◆ Because of scheduling limitations, you may present only one volunteered paper in Thursday, from 9:00 a.m. to oral or poster mode. If you have already had a volunteered abstract accepted, 2:00 p.m. please do not submit another. Abstract Fee: For this meeting, a nonrefundable abstract fee of $50 must accompany each Late-Breaking Research abstract submitted. Our Web-template form will ask for credit-card information. We have installed one of the best known and most respected BOOKSTORE Secure Server systems for transmission of your credit-card data to fully protect your confidential information. MEMBERSHIP Schedule: Abstracts will be reviewed by the Annual Program Committee. Electronic FOUNDATION acceptance notices will be sent out the first week in October giving the place and SAGE & PEP time of presentation. Late-Breaking Research Sessions (oral and poster) will be held on Thursday, October 23, 1997. Publication: The abstracts will not be published in the abstract volume, although they will be published on the Web along with the Web abstracts and paper copies will be made available on site. SALT LAKE CITY

28 GSA TODAY, August 1997 GSA SECTION MEETINGS — 1998

1998 Call for Papers Toronto, Ontario, Canada NORTHEASTERN SECTION SOUTHEASTERN SECTION October 26–29 March 19–21, 1998 March 30–31, 1998 Holiday Inn By the Bay, Charleston Civic Center, Metro Toronto Convention Portland, Maine Charleston, West Virginia Centre Abstract Deadline: Abstract Deadline: Sheraton Toronto Centre November 14, 1997 November 21, 1997 Hotel and Towers Submit completed abstracts to: Submit completed abstracts to: Marc C. Loiselle Peter Lessing General Chair: Jeffrey J. Fawcett, Maine Geological Survey WV Geological & Economic Survey University of Toronto 22 State House Station P.O. Box 879 Technical Program Chairs: Augusta, ME 04333-0022 Morgantown, WV 26507-0879 Denis M. Shaw, McMaster University, (207) 287-2801 (304) 594-2321 Andrew Miall, University of Toronto [email protected] [email protected] Due date for symposia and theme proposals: January 2, 1998 NORTH-CENTRAL SECTION CORDILLERAN SECTION Call for Field Trip Proposals: March 19–20, 1998 April 7–9, 1998 We are interested in proposals for single-day Ohio State University, Columbus, Ohio California State University, and multi-day field trips beginning or ending Abstract Deadline: Long Beach, California in Toronto, and dealing with all aspects of the November 14, 1997 Abstract Deadline: geosciences. Please contact the Field Trip Submit completed abstracts to: December 12, 1997 Chairs listed below. David H. Elliot Submit completed abstracts to: Pierre Robin, University of Toronto, Department of Geological Sciences James C. Sample Dept. of Geology, Ohio State University Department of Geological Sciences 22 Russell Street, Toronto, Ontario M5S 125 South Oval Mall California State University 3B1, Canada, (416) 978-3022, fax 416- Columbus, OH 43210 Long Beach, CA 90840 978-3938 (614) 292-5076 (562) 985-4589 Henry Halls, Erindale College, [email protected] [email protected] Mississauga, Ontario L5L 1C6, Canada, (905) 828-5363, fax 905-828-3717, [email protected] SOUTH-CENTRAL SECTION ROCKY MOUNTAIN SECTION March 23–24, 1998 May 25–26, 1998 University of Oklahoma, Northern Arizona University, CALL FOR Norman, Oklahoma Flagstaff, Arizona CONTINUING EDUCATION Abstract Deadline: Abstract Deadline: COURSE PROPOSALS December 1, 1997 January 8, 1998 Due December 1, 1997 Submit completed abstracts to: Submit completed abstracts to: Judson Ahern Wendell Duffield The GSA Committee on Continuing School of Geology & Geophysics U.S. Geological Survey Education invites those interested in University of Oklahoma 2255 Gemini Road proposing a GSA-sponsored or 100 E. Boyd St., Suite 810 Flagstaff, AZ 86001 cosponsored course or workshop to Norman, OK 73019-0628 (520) 556-7000 contact GSA headquarters for proposal (405) 325-3253 [email protected] guidelines. Continuing Education [email protected] courses may be conducted in conjunc- tion with all GSA annual or section ✁ meetings. We are particularly interested in receiving proposals for the 1998 SECTION MEETING ABSTRACT FORM REQUEST 1998 Toronto Annual Meeting or the To: GSA Abstracts Coordinator, P.O. Box 9140, Boulder, CO 80301-9140 1999 Denver Annual Meeting. or E-mail: [email protected] Proposals must be received by December 1, 1997. Selection Please send _____ copies of the 1998 GSA Section Meeting abstract form. of courses for 1998 will be made by February 1, 1998. For those planning ahead, we will also consider courses Name ______for 1999 at that time. For proposal guidelines or Address ______information, contact: Edna Collis, Continuing Education Coordinator, GSA headquarters, ______1-800-472-1988, ext. 134, E-mail: [email protected]. City ______State______ZIP ______

GSA TODAY, August 1997 29 precipitations kinetics … variograms, kriging, and uncertainty analysis … infinitesimal properties … cosmogenic nuclide systematics … paleoecosystems … vector mapping … geomicrobiology …

…if these words rock your world, come to Salt Lake City and take a GSA Continuing Education course…

Analysis of Veins in Sedimentary Rocks—An Introduction for Structural Geologists ❖ Techniques of Geostatistical Estimation and Simulation Applied to Environmental Geology ❖ Computer Visualization of Three-Dimensional Deformation and Application to Upper-Crustal Settings ❖ Applications of Environmental Isotopes to Solving Hydrologic and Geochemical Problems ❖ Buck Rogers, Field Geologist: 21st Century Electronic Wizardry for Mapping and Field Data Collection ❖ Dynamical Systems Modeling for Undergraduate Education: From Coleman Coolers to Computers ❖ Environmental Issues at Modern and Historic Mining Sites ❖ Geology of Coal Bed Methane: The Perspective From Basin and Thermal History Studies ❖ Geomorphic Applications of In Situ–Produced Cosmogenic Isotopes ❖ Visualization in the Geosciences ❖ Paleosols for Sedimentologists ❖ Practical Remote Sensing for Geology ❖ (and more than 30 field trips!)

GLOBAL CONNECTIONS The Geological Society of America Annual Meeting & Exposition Salt Lake City, Utah • October 20-23, 1997

Registration information and course and field trip descriptions were published in June GSA Today. For additional information, contact Edna Collis, Continuing Education and Field Trip Coordinator, GSA Meetings Department, P.O. Box 9140, Boulder, CO 80301, (303) 447-2020, ext. 134, fax 303-447-0648, E-mail: [email protected] or see GSA’s Web site: www.geosociety.org.

CALENDAR

Only new or changed information is published in GSA Today. 1997 Meetings A complete listing can be found in the Calendar section on the November Internet: http://www.geosociety.org. November 3–7, Scientific Inquiry for Planning & Managing the Grand Staircase–Escalante National Monument symposium, Cedar City, Utah. Information: Suzanne Winters, (801) 538-1038, fax 801-538-1547, suz.win- Send notices of meetings of general interest, in format below, to Editor, [email protected], or Marietta Eaton, (801) 865-5114, [email protected]. GSA Today, P.O. Box 9140, Boulder, CO 80301, E-mail: [email protected]. 1998 Meetings 1997 Penrose Conferences January January 11–16, American Meteorological Society Annual Meeting, September Phoenix, Arizona. Information: AMS, 45 Beacon St., Boston, MA 02108-3693, September 10–15, Faults and Subsurface Fluid Flow: Fundamentals (617) 227-2425, fax 617-742-8718. and Applications to Hydrogeology and Petroleum Geology, Albuquerque and Taos, New Mexico. Information: William C. Haneberg, February New Mexico Bureau of Mines and Mineral Resources, New Mexico Institute February 11–13, Mexican Paleontological Society VI National Conven- of Mining and Technology, 2808 Central Ave. SE, Albuquerque, NM 87106, tion, Mexico D.F., Mexico. Information: Marisol Montellano, Dept. de Paleon- (505) 262-2774, fax 505-255-5253, [email protected]. For more informa- tología, Inst. de Geología, UNAM, Ciudad Universitaria, Coyocán, México, D.F. tion, see http://www.nmt.edu/~haneberg/ 04510, México, phone 52-5-622-4280 or 4281, fax 52-5-550-8432, mar- Fluids.html. [email protected]. April September 23–28, Tectonics of Continental Interiors, Cedar City, Utah. April 27–30, Modern Preparation and Response Systems for Earth- Information: Michael Hamburger, Dept. of Geological Sciences, Indiana Uni- quake, Tsunami and Volcanic Hazards, Santiago, Chile. Information: versity, Bloomington, IN 47405, (812) 855-2934, fax 812-855-7899, Bruce A. Bolt, Dept. of Geology and Geophysics, University of California, [email protected]. Berkeley, CA 94720, fax 510-845-4816, [email protected], or J. Gutierrez, Inst. Geografica Militar, Santiago, Chile, fax 56-2-698-8278, [email protected].

30 GSA TODAY, August 1997 CLASSIFIED ADVERTISING

Published on the 1st of the month of issue. Ads (or can- Hydrology faculty, eight adjunct faculty, and 30 graduate Services & Supplies cellations) must reach the GSA Advertising office one students. Hydrology is part of the Department of Earth and month prior. Contact Advertising Department (303) Environmental Science, consisting of 16 faculty and 150 ALBORAN SCIENCE PUBLISHING. Have you seen our 447-2020, 1-800-472-1988, fax 303-447-1133, or undergraduate and graduate students. Additional geo- posters on "Societal Benefits of Geoscience?" Thumbnails E-mail:[email protected]. Please include com- science professionals on campus include the 28 staff and order forms are printed in GSA Today (May '97, plete address, phone number, and E-mail address with all members of the Bureau of Mines, New Mexico's geologi- p. 36/37) and AAPG Explorer (April '97, p. 58). Order correspondence. cal survey. For futher information on the position and on Now! Per line New Mexico Tech see http://griffy.nmt.edu/Hydro/posi- Per Line for each tion.html. Applicants should submit a letter of interest, ALBORAN SCIENCE PUBLISHING. Are you teaching for addt'l month resume, college transcripts, and the names of three refer- geologic map interpretation? Try "Structural Geology and Classification 1st month (same ad) ences to New Mexico Institute of Mining and Technology, Map Interpretation" by R. Weijermars, 1997, 320 line Human Resources, 801 Leroy Pl., Wells Hall Box C-048, Situations Wanted $1.75 $1.40 drawings, 83 photos, 129 exerc./sol., 378 pages (8.5 x Socorro, New Mexico 87801. To receive full consideration Positions Open $6.50 $5.50 11", flexicover). Excellent reviews. Strongly recom- all materials must be received by 1 September 1997. New Consultants $6.50 $5.50 mended. At $24.95 you cannot afford to miss this suc- Mexico Tech is an equal opportunity/affirmative action Services & Supplies $6.50 $5.50 cessful textbook/lab book. Order forms are printed in employer. Opportunities for Students GSA Today (April '97, p. 11) and AAPG Explorer (May first 25 lines $0.00 $2.35 '97, p. 28). You can also contact us by fax (Netherlands): MINERALOGY/PETROLOGY/STRUCTURAL GEOLOGY additional lines $1.35 $2.35 31 20 3640 145, or phone: 31 20 3640 331. Order Now! The Department of Geology and Geophysics, University of Code number: $2.75 extra Missouri-Rolla, announces a tenure-track position at the EARTH RESISTIVITY METER/BISON 2350B. $1600 assistant professor level. The successful candidate must Agencies and organizations may submit purchase order or with cables, reels and probes. Phone: Ken Maloney 541- hold the Ph.D., will be expected to teach mineralogy, payment with copy. Individuals must send prepayment 482-9151. petrology, and/or structural geology at the undergraduate with copy. To estimate cost, count 54 characters per line, level, and will develop a graduate research program (M.S. including all punctuation and blank spaces. Actual cost and Ph.D.) in one of those areas. Additional information may differ if you use capitals, centered copy, or special regarding the position and department can be obtained characters. Opportunities for Students from our web page or by writing to: Chairman, Department of Geology and Geo- Graduate Student Assistantships in Hydrogeology, To answer coded ads, use this address: Code # ----, physics, University of Missouri-Rolla, Rolla, MO 65409- University of Nebraska-Lincoln (UNL). The Conserva- GSA Advertising Dept., P.O. Box 9140, Boulder, CO 0410. The deadline for application is September 15, 1997. tion and Survey Division has 3 or 4 graduate research 80301-9140. All coded mail will be forwarded within UMR is an Equal Opportunity Employer. assistantships available for both Ph.D. and M.S. students 24 hours of arrival at GSA Today office. to start in either the 1997 fall semester or the 1998 spring HYDROGEOLOGIST semester. The 2-year assistantships are part of two pro- COLLEGE OF WILLIAM AND MARY jects; (1) Groundwater-surface water interaction and the Positions Open The Department of Geology at the College of William and impact of irrigation wells on river levels, and (2) the hydrol- Mary invites applications for a tenure-track assistant pro- ogy and geochemistry of saline wetlands. Projects will HYDROLOGY/SURFICIAL PROCESSES fessor beginning August 1998. The successful candidate involve well installation, aquifer analysis (pump-tests), The College of Wooster will teach an undergraduate field-based Hydrogeology, yearly monitoring, chemical and isotopic sampling and Applications are invited for a tenure-track assistant profes- Environmental Geology, and related courses, supervise numerical modeling. Applicants should have a strong sor position in the Department of Geology at The College senior research students, and conduct his/her research. background in geology with emphasis in hydrogeology of Wooster beginning August 1998. The successful candi- Expertise in applied geophysics and/or GIS is desirable. and geochemistry. Strong mathematical and computer date is expected to develop an introductory level course in Ph.D. required. Applicants should submit a statement of modeling skills are needed for one position. For informa- environmental geology and upper level courses in hydro- their undergraduate teaching and research experience tion on the projects, and an application package, contact geology and surficial processes/geomorphology; he/she and goals, a vitae, transcripts of all college work, and Drs. F. Edwin Harvey (feharvey@ unlinfo.unl.edu) or Xun also will occasionally teach a second-level course on pro- postal and e-mail addresses and telephone numbers of Hong Chen ([email protected]), Conservation and cesses and concepts in geology and a First-Year Seminar three references to Gerald H. Johnson, Chair, Department Survey Division, 113 NH, UNL, Lincoln, NE 68588-0517; course in critical inquiry. Wooster has a strong undergrad- of Geology, College of William and Mary, Williamsburg, (402) 472-8237. Complete project descriptions can be uate senior independent study program in which the suc- VA 23187. E-mail . Review found on Dr. Harvey's homepage at http://nesen.unl.edu/ cessful candidate will participate as an advisor. Candi- begins September 15, 1997. W&M is an AA/EEO university. csd/staff/harvey/feharvey.html. dates with an interest in the role of fluids in shallow Earth's crust and who are able to work with existing faculty and student research programs in structural geology, hydrothermal processes, and paleoenvironmental analysis are especially encouraged to apply. Applicants for this Director of Curriculum Development position should have a Ph.D. The College of Wooster is a highly selective liberal arts American Geological Institute institution with an enrollment of approximately 1700 men and women. The department consists of four faculty mem- he American Geological Institute invites applications for the position of Director of bers and approximately 50 geology majors. The depart- Curriculum Development from geoscience educators with experience in K–12 Earth- ment is housed in a recently renovated building and pos- T sesses a variety of modern research equipment, including science curriculum development and management of large educational projects. A an XRD, SEM, fluid inclusion stage, cathodoluminescence doctoral degree in the geosciences or Earth science education is required, and classroom microscope, paleomagnetic laboratory, and a seismometer. experience is preferred. Interested persons should send a letter of application, a curriculum vitae, and three letters of recommendation by This position provides an unparalleled opportunity for an Earth science professional October 15, 1997, to Dr. Lori Bettison-Varga, Chair of the committed to advancing the status of science education in the nation's schools based on Search Committee, Department of Geology, The College of Wooster, Wooster, Ohio 44691, in order to be consid- the National Science Education Standards and the educational goals of AGI and its ered for an interview at the GSA meeting in Salt Lake City. Member Societies. Closing date is November 15. The College of Wooster is an equal opportunity/affirmative action employer. The successful candidate will manage AGI's K–12 curriculum development projects from AGI headquarters in Alexandria, Virginia. S/he will interact on a day-to-day basis with ASSISTANT PROFESSOR OF HYDROLOGY New Mexico Institute of Mining and Technology invites project investigators, directors of other state and national education programs, applications for a new tenure-track position in the Hydrol- professional societies, and private sector supporters. S/he will provide intellectual ogy Program. The position is a joint appointment between oversight on the content, pedagogy, assessment, and publishing of project-related the Department of Earth and Environmental Science and the Geophysical Research Center, a state-funded materials in cooperation with project investigators. S/he will also manage logistical and research agency. Applicants should have a Ph.D. in the financial operations of funded projects. The successful candidate will also be expected to Earth Sciences or a related field at the time of appoint- identify and develop support for new program-related activities. ment. We seek candidates with expertise in water/land surface interactions (e.g., watershed hydrology, hydrogeo- Applicants should send a letter of interest, vita, and names/ addresses of three morphology, or hydroclimatology) who have strong quanti- tative skills and an interest in field problems. Excellence in references to the AGI Education Search Committee, American Geological Institute, 4220 research and potential for future growth are the most King Street, Alexandria, VA 22302-1502 (fax 703-379-7563). Appointment is anticipated important qualifications. Responsibilities will include devel- no later than September 1997. Review of applications will begin immediately. oping an active program of extramurally funded research, supervising and supporting graduate students, and teach- Applications will be accepted until the position is filled. For more information about AGI, ing two upper-division or graduate courses per year. The its programs and activities, visit our Web site at . AA/EOE. successful candidate will join a program of five full-time

GSA TODAY, August 1997 31 Geological Society of America

Annual Meeting and Exposition

Salt Lake City, Utah October 20–23 THE NATURE OF Preregistration Due September 19 MAGMATISM IN THE Program Schedule September GSA Today APPALACHIAN and the Web OROGEN See June GSA Today forfor informationinformation on:on: edited by ◆ Technical Program ◆◆Continuing Education A. Krishna Sinha, Courses Joseph B. Whalen and ◆◆Field Trips ◆◆Exhibits John P. Hogan, 1997 ◆◆Registration ◆ ◆Lodging and Travel The thermal evolution of mountain belts is commonly recorded in the distribution, origin, and ages of magmatism. In this volume, 20 contributors present the latest petrological, isotopic, and geochemical evidence to highlight the contribution of igneous rocks to the evolution of the Appalachian orogen in both Canada and the United States. These papers emphasize the use of modern geochemical and petrologic data to discriminate the sources yielding magmas, and thus the nature of the crust and mantle. The wealth of data available in this work provides a significant stepping- stone to more rigorous interpretation of the assembly and origin of the Appalachian orogen. MWR191, 438 p., indexed, ISBN 0-8137-1191-6, $135.00, GSA Members $108.00

For information: 1 For information: Memoir volumes are 8- /2" x 11" hardbound. Prices include shipping and handling. GSA Meetings Dept. P.O. Box 9140 Boulder, CO 80301 1-800-472-19881-800-472-1988 fax 303-447-1133 (303) 447-2020 www.geosociety.org (800) 472-1988 [email protected] Publication Sales • P.O. Box 9140 • Boulder, CO 80301 • 303-447-2020 http://www.geosociety.org