Vol. 8, No. 5 May 1998 INSIDE • Upcoming Penrose Conference GSA TODAY p. 16 • Book Reviews, p. 19 A Publication of the Geological Society of America • Calls for Service, p. 3, 23, 26

Comings and Goings of Global Glaciations on a Neoproterozoic Tropical Platform in Paul F. Hoffman, Department of Earth & Planetary Sciences, Harvard University, Cambridge, MA 02138 Alan J. Kaufman, Department of Geology, University of Maryland, College Park, MD 20742 Galen P. Halverson, Department of Earth & Planetary Sciences, Harvard University, Cambridge, MA 02138

ABSTRACT many Neoproterozoic glacial deposits are Kennedy, 1996)—a climatological or geo- rich in carbonate debris and are directly chemical paradox, given that inorganic An enduring enigma of Neoprotero- overlain by carbonates containing struc- zoic Earth history is the intimate associ- tures indicative of sea-floor precipitates ation of glacial diamictites with typical (Fig. 1)(Roberts, 1976; Fairchild, 1993; Global Glaciations continued on p. 2 warm-water carbonates. Among the many hypothesized explanations for this paleoclimatic dichotomy are high orbital obliquity, true polar wander, reduced solar luminosity, snowball albedo, CO2 drawdown, stagnant ocean overturn, and reinterpretation of diamictites as mega-impact ejecta. The Otavi on the in Namibia contains two discrete intervals of diamictite and associated glaciomarine deposits, sand- wiched by thick carbonates from which we have obtained detailed carbon-iso- topic records. From subsidence analysis, we estimate maximum rates of shallow- water sediment accumulation. The mag- nitude and duration of isotopic varia- tions permit critical assessment of the existing hypotheses.

INTRODUCTION Louis Agassiz’s (1840) apocalyptic vision of ice ages so severe that continents were glaciated in the tropics and organic activity was stilled on land and sea was overwrought for the Quaternary, but what about the extraordinary events of the late Neoproterozoic (750–543 Ma)? Brian Har- land (1964) first drew attention to the global distribution of infra-Cambrian glacial deposits and postulated that they extended into the tropics. This view was not widely accepted, however, because multiple glaciogenic intervals occur in some sections, making the extent of any individual glaciation dependent on corre- lation. Reliable paleomagnetic tests have been difficult to perform, but there is now strong evidence for equatorial glaciation Figure 1. A: Generalized (Hoffmann and Prave, 1996) of Neoproterozoic cover on the at sea level in South Australia at ~600 Ma Congo craton in northern Namibia, showing geochronological constaints. B: Galen Halverson points to (Schmidt and Williams, 1995; Sohl, 1997) the sharp contact between Ghuab diamictite and Maieberg cap carbonate. Below him is a graded debris flow, behind him is laminated dololutite with numerous dropstones, and above him are deep-water and with less certainty in northwestern rhythmites with undulations due to isopachous cement sheets. All three units are composed entirely of Canada at ~720 Ma (Park, 1997). Tropical dolomite. C: Ice-rafted dolomite dropstone pierces underlying laminae in glaciomarine Ghaub dololutite. glaciation has also been advocated because Coin is 2 cm in diameter. IN THIS ISSUE GSA TODAY May Vol. 8, No. 5 1998 Comings and Goings of Global Washington Report ...... 18 Glaciations on a Neoproterozoic Book Reviews ...... 19 GSA TODAY (ISSN 1052-5173) is published monthly Tropical Platform in Namibia . . . . . 1 by The Geological Society of America, Inc., with offices at 3300 GSAF Update ...... 20 In Memoriam ...... 2 Penrose Place, Boulder, Colorado. Mailing address: P.O. Box Call for Committee Service ...... 23 9140, Boulder, CO 80301-9140, U.S.A. Periodicals postage Correction ...... 2 paid at Boulder, Colorado, and at additional mailing offices. 1998 Section Officers ...... 24 Postmaster: Send address changes to GSA Today, Member- Call for IEE Director ...... 3 ship Services, P.O. Box 9140, Boulder, CO 80301-9140. GSA on the Web ...... 24 GSA Committees Need You ...... 9 Copyright © 1998, The Geological Society of America, Inc. Jim Clark Retires ...... 24 (GSA). All rights reserved. Copyright not claimed on content Rock Stars—N. L. 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Contact Membership Services at (800) 472-1988, August 6, 1997 of estimating the time scale of their assoc- (303) 447-2020 or [email protected] for member- ship information. Nonmembers & Institutions: Free iated isotopic anomalies. Such data gain with paid subscription to both GSA Bulletin and Geology, sway only in the arena of ideas; thus, we otherwise $50 for U.S., Canada, and Mexico; $60 else- Global Glaciations continued from p. 1 begin with a partial review of current where. Contact Subscription Services. Single copies may be requested from Publication Sales. Also available on an hypotheses. annual CD-ROM, (together with GSA Bulletin, Geology, GSA carbonate precipitation is normally a Data Repository, and an Electronic Retrospective Index to CONTENDING HYPOTHESES journal articles from 1972); $89 to GSA Members, others warm-water phenomenon. call GSA Subscription Services for prices and details. Claims: Accompanying the late Neoprotero- A welter of hypotheses contend to For nonreceipt or for damaged copies, members contact Membership Services; all others contact Subscription Ser- zoic ice ages are huge negative carbon- shed light on the Neoproterozoic climate vices. Claims are honored for one year; please allow suffi- isotopic excursions, unique in the past puzzle. Seeking primarily to explain the cient delivery time for overseas copies, up to six months. 2 b.y. (Fig. 2). Carbonates are very strongly paleomagnetic data, Williams (1975, 1993) 13 STAFF: Prepared from contributions from the GSA staff enriched in C between the ice ages but proposed that Earth’s axial tilt (the obliq- and membership. plunge to extremely depleted values in uity of the ecliptic) exceeded 54° until the Executive Director: Donald M. Davidson, Jr. lithologically distinctive transgressive end of the Proterozoic, after which it stabi- Science Editors: Suzanne M. Kay, Department of Geological Sciences, , Ithaca, NY 14853; carbonate units that “cap” the glacial lized at much lower values (23.5° today). Molly F. Miller, Department of Geology, Box 117-B, Vanderbilt deposits and commonly extend far Accordingly, Earth’s climatic zonation University, Nashville, TN 37235. Forum Editor: Bruce F. Molnia, U.S. Geological Survey, beyond them, aiding regional-scale corre- would have been reversed in the Protero- MS 917, National Center, Reston, VA 22092 lations (Knoll et al., 1986; Kaufman and zoic, meaning lower insolation at low lati- Managing Editor: Faith Rogers Knoll, 1995; Kaufman et al., 1997). Such tudes than at the poles. On the other Production Editor and Coordinator: Joan E. Manly Graphics Production: Joan E. Manly, Leatha L. Flowers large isotopic shifts signify a combination hand, the seasonal cycle would have been of changes in (1) fractional organic to total greatly amplified, resulting in hot bian- ADVERTISING: Classifieds and display: contact Ann carbon burial rates (Scholle and Arthur, nual summers, which do not favor glacia- Crawford, (303) 447-2020; fax 303-447-1133; acrawfor@ geosociety.org. 1980), (2) biological productivity in the tion. The association of carbonates and surface ocean (Broecker, 1982), (3) vertical glacial deposits is not explained by this Issues of this publication are available as electronic Acrobat files for free download from GSA’s Web Site, http://www. circulation rate for the whole ocean (Brass model, nor is the middle Proterozoic geosociety.org. They can be viewed and printed on various et al., 1982), (4) isotopic composition of glacial hiatus (Fig. 2); once low obliquities personal computer operating systems: MSDOS, MSWin- carbon sources (Derry and France-Lanord, were established, high obliquities should dows, Macintosh, and Unix, using the appropriate Acrobat reader. Readers are available, free, from Adobe Corporation: 1996; Dickens et al., 1997), and (5) iso- not recur (Laskar et al., 1993). The model http://www.adobe.com/acrobat/readstep.html. topic fractionation related to carbonate does have the merit of a simple falsifying This publication is included on GSA’s annual ion concentration (Spero et al., 1997). All test—high-latitude glaciation. Only mod- CD-ROM, GSA Journals on Compact Disc. are linked to global climate change. Here erately high (30°–40°S) latitude glaciations Call GSA Publication Sales for details. 50% Total we describe the stratigraphic relations of have been documented paleomagnetically Printed in U.S.A. using pure soy inks. Recoverd Fiber two Sturtian (750–700 Ma) glacial intervals (Torsvik et al., 1995). 10% Postconsumer on a carbonate-dominated platform in

2 GSA TODAY, May 1998 DIRECTOR — Institute for Environmental Education

The Geological Society of America (GSA) Plus, the successful candidate will be the principal recognizes that earth systems science architect of a NEW INITIATIVE to: is central to environmental issues, prac- ➤ Stimulate earth systems science activities throughout GSA; tices, policies, and problems in society ➤ Catalyze cooperative interactions among Earth, Life, today. Thus, GSA is soliciting applica- Planetary, and Social Science groups on earth systems science. tions for the position of Director for the Institute of Environmental Education Desirable characteristics for the successful (IEE). Through Institute programs, GSA candidate include: offers an interface between the public, busi- • Interest and experience in the geosciences, particularly ness and industry, government, and the geological community involving earth systems science and/or applied settings; on matters of earth systems science and related public policy • M.S. degree required; Ph.D. in science or engineering desirable; issues. The Institute fosters communication and application • Self-starter who is organized, productive, and able to work as of geoscience information relevant to environmental issues, part of a team; education and research related to earth systems problems • Demonstrated interest and experience in public policy issues; and public policy, and programs to facilitate professional devel- • Fund-raising abilities; opment in the area of environmental earth science. • Demonstrated ability to communicate effectively both orally and in writing; Responsibilities will include: • Ability to work effectively with diverse groups and individu- • Development of innovative Annual and Section meeting als from business, government, education, media, and the environmental forums; general public. • Coordination of GSA public policy activities, and enhancement of a program to involve geoscientists in issues The position is available July 1, 1998, and will remain of public policy and media outreach; open until a suitable qualified candidate has been identified. • Initiation of workshops and technical programs on Salary will be commensurate with experience. The position environmental and earth systems science matters related will be at GSA headquarters in Boulder, Colorado. Candidates to public awareness; should submit a resume, a letter of interest, and the names and • Management of mentorship programs that introduce addresses of three professional references as soon as possible to students to applied environmental geoscience career Donald M. Davidson, Jr., Executive Director, Geological Society opportunities; of America, 3300 Penrose Place, P.O. Box 9140, Boulder, • Assistance in fund-raising activities and general support Colorado 80301. of the GSA education and outreach enterprise;

Another approach that avoids global nonhydrostatic moment of inertia tensor. (Gold, 1955; Fisher, 1974). Consequently, glaciation, but which could explain rapid The requisite condition arises if the geoid continents located near the poles of the transitions from normal low-latitude to figure closely approximates a prolate ellip- prolate axis will undergo 90° rotations, and high-latitude conditions, is inertial-inter- soid: the prolate axis will stabilize in the continents located far from the axis will change true polar wander (IITPW). True equatorial plane to conserve angular migrate through 90° of latitude at veloci- polar wander refers to rotation of the momentum (Goldreich and Toomre, ties far exceeding those due to plate tecton- entire solid shell (crust and mantle) of 1969), but if the other two axes are nearly ics. IITPW has been invoked in the inter- Earth relative to the spin axis, a special equal, small changes in mass distribution pretation of Cambrian paleomagnetic data case of which involves interchange of the may cause the globe to rotate 90° around (Kirschvink et al., 1997), and if the inferred major and intermediate axes of Earth’s the prolate axis in a few million years prolate geoid figure was inherited from the former supercontinent (1.05–0.72 Ga), then IITPW may have occurred several times in the late Neoproterozoic (Evans, 1998). This model attributes the carbonate- glacial association to rapid changes in pale- olatitude; it does not explain low paleo- magnetic inclinations obtained from the glacial deposits themselves (Park, 1997; Sohl, 1997). No changes in global climate are required in the model, but they would surely occur as ocean circulation patterns changed in response to migration of Earth’s rotation axis. Continents moving in or out of the polar regions would experi- ence short-term relative-sea-level falls or rises, respectively, because of their migra- tion with respect to Earth’s rotational bulge (Mound and Mitrovica, 1998). These sea- level changes would mimic those expected from glacio-eustasy. Figure 2. Secular variation in δ13C (PDB) values of marine carbonates from 2.5 Ga to the present (com- piled from Berner, 1989; Kaufman and Knoll, 1995; Kaufman et al., 1997, and references therein). Note enriched late Neoproterozoic isotopic values and high-amplitude negative excursions coincident with glaciations, indicated by triangles. Bar indicates inferred Otavi Group age span. Global Glaciations continued on p. 4

GSA TODAY, May 1998 3 Figure 3. Regional correlation of depositional sequences on the western Otavi platform and its southern foreslope. Inset map shows locations of measured sections and Huab ridge.

Global Glaciations continued from p. 3 values (Kump, 1991). Only if productivity oversaturated surface waters (Kaufman et ceased for hundreds of thousands of years al., 1991, 1997; Kaufman and Knoll, 1995; Rampino (1994) suggested that the would δ13C approach the ocean input Grotzinger and Knoll, 1995). This hypothe- purported glacial deposits are actually value of –5‰ (Kump, 1991). Barring a suc- sis has been extended to account for the impact ejecta. His argument is that ballistic cession of large impacts, the isotopic excur- end-Permian mass extinction (Knoll et al., debris flows resulting from large impacts sions should strictly postdate the ballistic 1996), which has a carbon-isotopic signa- exhibit many features conventionally iden- ejecta deposits, providing a stratigraphic ture somewhat comparable to the Neopro- tified with glacial and glaciomarine test for the impact hypothesis. terozoic glacial events (Holser et al., 1989; deposits, including faceted and striated The occurrence of iron-formation Magaritz, 1989). clasts and grooved bedrock pavements. in several Neoproterozoic glacial deposits The Sun’s luminosity was only Rampino (1994) did not discuss carbon- inspired the hypothesis that glaciation was 93%–94% of its present value in the late isotopic anomalies, but negative excur- preceded by deep ocean anoxia, favoring Neoproterozoic because main-sequence sions do accompany impact-induced mass organic carbon burial. Invigorated thermo- stars radiate more energy as their helium extinctions (Hsü and McKenzie, 1985; haline circulation during and after glacia- cores grow more massive (Gough, 1981). Zachos et al., 1989). Cessation of surface tion would result in upwelling of ferrous However, the absence of middle Proterozoic ocean productivity (Strangelove ocean) iron-, bicarbonate-, and CO2-charged bot- glacial deposits (Fig. 2) shows that this fact 3 would cause rapid (<10 yr) loss of the tom waters, releasing CO2 to the atmo- alone cannot explain late Neoproterozoic –3 ocean’s isotopic gradient (~2‰ in the sphere and driving the precipitation of glaciations. CO2 concentrations of 10 b present ocean), meaning that δ13C in the ferric oxide and isotopically depleted bicar- (three times pre-industrial values) would surface ocean would fall to whole-ocean bonate as in oxic and highly have offset the reduced solar luminosity,

4 GSA TODAY, May 1998 Figure 4. A: Thermal subsidence (dashed lines) and sediment accumulation (solid lines) curves generated by lithospheric stretching factors (ß) of 1.25 and 1.50. Sediment accumulation is calcu- lated as thermal subsidence plus loading by car- bonate sediment, filling available accommodation to sea level. Maximum thickness of ~2.8 km for Otavi Group after 160 m.y. implies ß ~1.25. B: Curves as above for first 25 m.y. of thermal sub- sidence generated by ß ~1.25. Thickness of the section (480 m) containing the negative carbon- isotopic excursion associated with Ghaub glacia- tion, beginning and ending with shallow-water deposits and corrected for glacial , implies a duration of ~9.2 m.y.

but this dependence could have left Earth susceptible to severe chilling in event of CO2 drawdown (Kasting, 1992). Coupled energy-balance models suggest that such scenarios are sensitive to the distribution of land masses but that CO2 concentrations would have to fall to 10–4 b (0.3 times pre- industrial values) to drive tropical sea- surface temperatures to the freezing point even with reduced solar luminosity (Mar- shall et al., 1988; Crowley and Baum, 1993). Nevertheless, Kirschvink (1992) suggested that albedo feedback from extensive sea-ice formation on a globe with an equatorial ring of continents might lead to a “snowball Earth,” in which the ocean is decoupled from the atmosphere by global pack ice, with pro- found implications for ocean chemistry and biological activity. For example, exchange of O2 between the ocean and atmosphere would be inhibited, permit- ting ferrous iron generated at mid-ocean ridges or leached from bottom sediments to build up in solution, only to be precipi- tated as ferric iron-formation upon venti- lation of the ocean when the ice pack receded (Kirschvink, 1992).

Figure 5. Representative stratigraphic section from the intra-shelf basin north of the Huab ridge (part G–H in Fig. 3). Top of left column continues at base of right column. Note anomalous thicknesses of Global Glaciations continued on p. 6 Rasthof and Maieberg postglacial cap carbonates.

GSA TODAY, May 1998 5 Global Glaciations continued from p. 5 subsidence would be largely complete the Ghaub glaciation, reflecting rifting at (Fig. 4A). The maximum of 2.8 km of the southern margin of the platform, carbonate accumulated during thermal before declining to only 4 m in the Eland- OTAVI CARBONATE PLATFORM subsidence, after correction for sediment shoek Formation above the Maieberg cap In late Neoproterozoic time, the loading, amounts to ~0.73 km of tectonic carbonate. Thus, the cap carbonates Congo craton was a low-lying platform subsidence. This amount of ultimate ther- require highly anomalous amounts of the size of the conterminous United mal subsidence would be induced by a uni- accommodation. From the onset of gla- States. It was blanketed by carbonates and form synrift stretching factor ß ~1.25 and ciation to the end of cap-carbonate dep- shales containing regionally mappable would begin with tectonic subsidence rates osition, the accumulated sediment must diamictite units of glacial origin (Hambrey of ~14 m/m.y., averaged over the first 10 equal the sum of the tectonic subsidence, and Harland, 1981). Two discrete glacio- m.y. (McKenzie, 1978). This corresponds, net glacial erosion/deposition, and the genic intervals are contained in carbonates with sediment loading, to a carbonate effect of sediment loading. Compaction is of the Otavi Group (Fig. 1A), which drape accumulation rate of ~52 m/m.y. (Fig. 4B). negligible in the Otavi Group carbonates the southern promontory of the craton We take this as a rough upper bound for and <20 m of net erosion occurred on the in northern Namibia (Fig. 3). We consider the purpose of constraining the minimum platform during the Ghaub glaciation. the Otavi Group to be entirely pre-Ven- duration of the isotopic anomalies. Given the average thickness of the dian in age (Fig. 2), on the basis of chemo- Maieberg cap carbonate of 280 m (Fig. 3) and biostratigraphic arguments. Carbon- GLACIAL DEPOSITS AND and the maximum sediment accumulation isotopic compositions above +8‰ POSTGLACIAL CAP CARBONATES rate of 52 m/m.y. calculated earlier, the observed near the top of the Otavi Group minimum time required to create sufficient The glacial deposits are characterized (Kaufman et al., 1991) are unknown in the accommodation would be 5.4 m.y. Note by diamictites, which are sheets of unstrat- Vendian (Kaufman and Knoll, 1995), and that this is not the minimum time for cap ified wackestone carrying outsize matrix- Vendian fossils, abundant in the Nama carbonate deposition, which could be far supported clasts of carbonate and base- Group carbonates of southern Namibia less, but rather the total time for the glacia- ment rocks. Within both the Chuos and (Grotzinger et al., 1995), are absent from tion as well as the cap carbonate. It is Ghaub glacial units (Fig. 3), separate the Otavi Group. Paleomagnetic data impossible to estimate the partitioning of diamictite sheets differ in composition, from the eastern part of the Congo craton time between the two because of transient but clast and matrix compositions covary, (Meert et al., 1995; Meert and Van der glacio-eustatic and glacio-isostatic effects indicating a common origin. Overall, Voo, 1996) imply that the Otavi Group (Boulton, 1990). For example, postglacial basement debris is more abundant in the was at ~12°S paleolatitude at 743 ± 30 Ma sea-level rise can create much accommoda- Chuos, and the Ghaub diamictites are nor- and ~39°S at 547 ± 4 Ma (compare with tion, but it will subsequently be eliminated mally dominated by debris from directly age constraints in Fig. 1A). by glacial rebound. Postglacial cap carbon- underlying carbonates. The Chuos diamic- The Otavi Group is exposed in fold ates described elsewhere are relatively thin tites are associated with fluvial outwash belts along the southern and western bor- (Fairchild, 1993; Kennedy, 1996) but they facies and fill paleovalleys with up to ders of the cratonic promontory (Miller, may represent only the transgressive parts 180 m of local relief. Such incision is 1997). The southern belt coincides with of postglacial depositional sequences. It is observed beneath the Ghaub diamictites the edge of the Otavi platform, which is only from the perspective of sequence only on the southern foreslope, where they flanked by correlative slope and deep-sea stratigraphy that the anomaly in post- are intercalated with subaqueous debris fan deposits draped over extended Congo glacial accommodation becomes apparent, flows and topped by laminated dololutite crust (Henry et al., 1990). A long-lived an aspect that escaped notice in the lithos- choked with carbonate dropstones (Fig. 1, basement high, the Huab ridge (Porada tratigraphic recognition of cap carbonates. B and C). Both glacial intervals have highly et al., 1983), separates the platform mar- Moreover, the anomaly stands out only complex and variable internal stratigra- gin from an intra-shelf basin to the north. when the cap carbonates are viewed in the phies, but their external contacts are The ridge was intermittently active in sequence-stratigraphic context of the Otavi remarkably similar and consistent. On the early and middle Otavi Group time, shed- Group as a whole. platform, their basal contacts show intense ding clastic wedges bilaterally into the The two cap carbonates have distinc- brecciation of the underlying carbonates. flanking carbonates. The western belt pro- tive and highly unusual lithologies (Fig. 6). Both of their upper contacts are knife- vides a transverse profile of the intra-shelf The Rasthof is dark to medium gray, mostly sharp and lack lag deposits or any evidence basin and the Huab ridge (Fig. 3), which dolomite and relatively carbonaceous of hiatus. Where the glacial deposits are along with the western part of the south- (0.03–0.3 wt% C); the Maieberg is pale subaerial, the upper contact is a smooth ern margin has been the focus of our field cream to pink, mostly limestone and flooding surface; where they are subaque- work. Another basement high occurs near extremely lean (0.001–0.02 wt% C). The ous, there is simply an abrupt cessation of the Namibia- border, 300 km to the complete Rasthof sequence in the intra- ice-rafted debris. north of the Huab ridge, and the scale and shelf basin consists essentially of three The Rasthof and Maieberg cap carbon- structure of the intra-shelf basin and base- stratigraphic units (Fig. 5). The basal unit ates (Fig. 5) directly overlie the Chuos and ment highs are remarkably similar to the comprises finely and smoothly laminated Ghaub glacial units, respectively, or their present Namibian continental shelf (Light micrite and varies from 5 to 60 m in thick- equivalent subglacial erosion surfaces et al., 1993). ness, dependent on the presence of centi (Fig. 3). They are single depositional Regional subsidence patterns and meter-scale allodapic (turbidites). sequences without internal exposure overstepping of growth faults suggest that The top of the flat-laminated unit is marked surfaces, whose average thickness of rifting of the western and southern mar- by profligate development of irregular 200–300 m is an order of magnitude gins of the Otavi platform ceased shortly domal stromatolites, the peculiar geometries greater than that between successive expo- before 758 Ma and shortly after 746 Ma, of which suggest synaggradational, fault- sure surfaces in other parts of the platfor- respectively (Fig. 1A, Hoffman et al., 1996). propagation folds, verging in all directions. mal Otavi Group. Average parasequence If carbonate sedimentation continued until By implication, stromatolite development thickness is 20 m in the Ombombo Sub- the platform collided with the South was a response to lateral growth expansion. group below the Chuos Formation and American cratons at ~600 Ma (Stanistreet Up-section, the stromatolite unit contains 8 m in the Gruis Formation above the et al., 1991; Machado et al., 1996; numerous coiled roll-ups (Fig. 6A), which Rasthof cap carbonate. It increases again to Trompette, 1997), the Otavi Group repre- formed while the sediment was cohesive 30 m in the Ombaatjie Formation below sents ~160 m.y., by which time thermal (microbially bound?), but pliable (lightly

6 GSA TODAY, May 1998 mineralized). Also present are irregular man and Knoll, 1995). Even the brecciated of 500 m. On the basis of previously esti- synsedimentary collapse breccias, composed and ferruginized samples deliberately col- mated maximum thermal subsidence rates of microbialaminite blocks and void-filling lected at exposure surfaces rarely have and assuming <20 m of glacial erosion thrombolite. The thick stromatolitic unit is anomalous carbon-isotopic values, indicat- beneath the Maieberg cap carbonate on devoid of desiccation structures and current ing that soil waters were not significantly the platform, the minimum duration of bedforms. At its top, the lamination fades depleted by decomposition of organic car- the negative isotopic excursion was and the stromatolites pass cryptically into bon. Furthermore, the carbon-isotopic 9.2 m.y. (480 m ÷ 52 m per m.y.; Fig. 4B). regressive pale gray grainstones, which trends for closely spaced samples are strati- Regional sequence stratigraphic mapping coarsen upward to a sequence boundary graphically coherent and regionally repro- provides no evidence of growth faulting marked by tepees and chert-breccias. ducible. coincident with the isotopic excursion, The basal transgressive unit of the We have obtained δ13C values for which might have produced anomalous Maieberg cap carbonate (Keilberg Member ~800 samples collected through the entire subsidence rates, hence less time, during of Hoffmann and Prave, 1996) on the plat- Otavi Group at different locations. These the interval. form is an unusual stromatolitic dolomite data (incorporated in Fig. 2) and their (Fig. 6B), highly reminiscent of the post- interpretation have been submitted for DISCUSSION AND CONCLUSIONS glacial Noonday dolomite (Sturtian?) in publication elsewhere. The thick, shallow- Let us now return to the contending eastern California (Wright et al., 1978; water carbonates of the Ombombo Sub- hypotheses. (1) The high-obliquity hy- Hegenberger, 1987). This pale dolomite unit group are strongly and uniformly enriched pothesis (Williams, 1975, 1993) does not consists of microbialaminite and long slen- in 13C (>+5‰), consistent with preglacial account for the intimate association of der columnar stromatolites, between which Neoproterozoic carbonates worldwide glacial deposits with carbonates including are persistent synoptic depressions forming (Kaufman et al., 1997). An influx of silici- inorganic sea-floor aragonite precipitates vertical sediment- and cement-filled clastics (from the Huab ridge) and ero- requiring warm-water conditions, exempli- “tubes.” The stromatolite member thickens sional truncation at the top of the fied by the basal Maieberg reefal cement over the Huab ridge and develops into a Ombombo Subgroup create problems in fans. (2) The inertial-interchange true polar mounded reef complex at the platform mar- obtaining data for the youngest pre-Chuos wander hypothesis that certain regions gin. Talus blocks at the base of the reef com- sediments. The basal Rasthof carbonates migrated rapidly between low and high lat- plex are infilled by meter-scale silica fans, are strongly depleted in 13C, beginning itudes (Kirschvink et al., 1997) does not pseudomorphic after aragonitic sea-floor near –4‰ and rising to ~0‰ near the top explain the temporal association of glacial cements. The stromatolite member is over- of the flat-laminated member. At the base deposits with large carbon-isotopic excur- lain transgressively by marly rhythmite, fol- of the overlying stromatolitic member, sions. Nor do we find transitional mid-lati- lowed by a thick regressive sequence of pink δ13C values rise abruptly and ultimately tude facies between the diamictites and limestone rhythmite, pale dolomite rhyth- stabilize near +5‰ for >150 m through the their respective cap carbonates, as pre- mite, and dolomite grainstone that coarsens remainder of the Rasthof Formation. The dicted by this hypothesis. (3) The sugges- upward to an exposure surface made promi- shift from negative to positive values is tion that the diamictites are mega-impact nent by downward-penetrating boxwork widely correlated with the onset of deep- ejecta (Rampino, 1994), implying that the chert. Directly above the sequence bound- water stromatolite development in the associated isotopic excursions signify ary are multitudinous meter-scale parase- intra-shelf basin. impact-induced mass extinctions, is con- quences with ubiquitous tepee structures, Prior to the Ghaub glaciation, δ13C tradicted by the onset of the negative iso- representing the basal member of the kilo- values through most of the Ombaatjie topic shift, which predates the Ghaub meter-thick Elandshoek peritidal platform. Formation hovered between +5‰ and diamictite. Moreover, we do not rely on The Keilberg stromatolite member is absent +9‰, exemplifying the familiar preglacial ambiguous criteria for recognizing glacial on the southern foreslope, where the basal enrichment in 13C. However, the ultimate deposits such as striated and faceted clasts, Maieberg cap carbonate consists of pale Ombaatjie shallow-water parasequence, which are difficult to observe in carbonate- dolomite rhythmite, sheeted with early directly beneath remnants of Ghaub dominated diamictites, but on stratigraphic isopachous carbonate cement (Fig. 1B). diamictite or the Maieberg cap carbonate, relations and abundant dropstones, around Carbon-isotopic curves indicate that the displays a monotonic downward trend which only the subjacent laminations are Maieberg cap carbonate thins dramatically from +5‰ at the base to –3‰ at the top, deformed and pierced. (4) The ocean-over- from the platform onto the foreslope, and reaching –5‰ in some sections. This turn hypothesis (Kaufman et al., 1991, that most of the rhythmite and rhythmite- preglacial isotopic shift occurs in at least 1997; Kaufman and Knoll, 1995; breccia section above the Ghaub diamictite nine sections over a north-south distance Grotzinger and Knoll, 1995; Knoll et al., is a foreslope facies of the Elandshoek plat- of 150 km, and Kennedy et al. (1997) 1996) predicts that negative isotopic excur- form (Fig. 3). reported a somewhat smaller shift beneath sions should be short-lived, limited by the the Ghaub diamictite well to the east of residence time for carbon in the ocean, lib- CARBON-ISOTOPIC RESULTS our sections. There is little change in δ13C erally estimated at 105 yr (Kump, 1991). values across the glacial interval: the basal The carbon-isotopic composition The negative excursion associated with the Maieberg cap carbonate begins near –3‰ of Phanerozoic marine carbonates is Ghaub glaciation, requiring an estimated and declines gradually up-section to a complicated by the vital effects of skeletal minimum duration of 9.2 m.y. for 125 m nadir of –6‰ about 20 m above the zone organisms and pervasive bioturbation. Pro- of net thermal subsidence, exceeds the of inferred maximum flooding. While δ13C terozoic carbonates are not plagued with predicted time limit by two orders of values gradually rise above this level, they these problems. The primary Otavi Group magnitude. remain negative through the sequence carbonates were pure lime muds, silts, So what remains? Sherlock Holmes’s boundary at the top of the Maieberg For- sands, and microbial micrites, most of dictum—that when all other hypotheses mation. In fact, the crossover to positive which underwent early fabric-retentive fail, the one that remains must be true—is δ13C values occurs ~200 m above the base dolomitization, rendering them relatively not always appropriate in science because of the Elandshoek Formation, which is impermeable. Elemental ratios sensitive not all possible hypotheses are known. In composed of repetitious peritidal parase- to diagenesis indicate minimal alteration this instance, however, we believe that one quences with ubiquitous subaerial expo- of most samples (for details of analytical of the contending hypotheses, with more sure surfaces. Thus, the overall negative procedures used in screening for diagenetic isotopic excursion begins and ends in peri- alteration, see Kaufman et al., 1991; Kauf- tidal sediments and spans a total thickness Global Glaciations continued on p. 8

GSA TODAY, May 1998 7 Hoffman, P. F., Hawkins, D. P., Isachsen, C. E., and Bowring, S. A., 1996, Precise U-Pb zircon ages for early Damaran magmatism in the Summas Mountains and Welwitschia inlier, northern Damara belt, Namibia: Geological Survey of Namibia Communications, v. 11, p. 47–52. Hoffman, P. F., Halverson, G. P., Kaufman, A. J., and Soffer, G., 1998, Snowball Earth and Neoproterozoic stratigraphy [abs.]: Eos (American Geophysical Union Transactions), Annual Spring Meeting (in press). Hoffmann, K.-H., and Prave, A. R., 1996, A preliminary note on a revised subdivision and regional correlation of the Otavi Group based on glaciogenic diamictites and associated cap dolostones: Geological Survey of Namibia Communications, v. 11, p. 77–82. Holser, W. T., and 14 others, 1989, A unique geochemi- cal record at the Permo/Triassic boundary: Nature, v. 337, p. 39–44. Hsü, K. J., and McKenzie, J. A., 1985, A “Strangelove” ocean in the earliest Tertiary, in Sundquist, E. T., and Broecker, W., eds., The carbon cycle and atmospheric CO2: Natural variations Archean to present: American Geophysical Union Monograph 32, p. 487–492. Figure 6. Unusual lithologies in postglacial cap carbonates. A: Microbial roll-ups in middle Rasthof cap carbonate (2-cm-diameter coin). B: Vertical “tubes” in basal Maieberg cap carbonate (10 cm scale Kasting, J. F., 1992, Proterozoic climates: The effect of divisions). changing atmospheric carbon dioxide concentrations, in Schopf, J. W., and Klein, C., eds., The Proterozoic biosphere: Cambridge, UK, Cambridge University Press, p. 165–168.

Global Glaciations continued from p. 7 Brass, G. W., Southam, J. R., and Peterson, W. H., 1982, Kaufman, A. J., and Knoll, A. H., 1995, Neoproterozoic Warm saline bottom water in the ancient ocean: variations in the C-isotopic composition of seawater: Nature, v. 296, p. 620–623. Stratigraphic and biogeochemical implications: Precam- elaboration than is possible here, provides brian Research, v. 73, p. 27–49. a satisfactory explanation consistent with Broecker, W. S., 1982, Ocean chemistry during glacial times: Geochimica et Cosmochimica Acta, v. 46, Kaufman, A. J., Hayes, J. M., Knoll, A. H., and Germs, the data (Hoffman et al., 1998). Whether p. 1689–1706. G. J. B., 1991, Isotopic compositions of carbonates and or not Agassiz’s (1840) vision of panglacial organic carbon from upper Proterozoic successions in Crowley, T. J., and Baum, S. K., 1993, Effect of Namibia: Stratigraphic variation and the effects of dia- catastrophes is valid for the Neoprotero- decreased solar luminosity on late Precambrian ice genesis and metamorphism: Precambrian Research, zoic, Namibia teaches us that Agassiz was extent: Journal of Geophysical Research, v. 98, v. 49, p. 301–327. p. 16,723–16,732. correct when he said, “If you learn about Kaufman, A. J., Knoll, A. H., and Narbonne, G. M., Nature in books, when you go out of doors Derry, L. A., and France-Lanord, C., 1996, Neogene 1997, Isotopes, ice ages, and terminal Proterozoic earth growth of the sedimentary organic carbon reservoir: history: National Academy of Sciences Proceedings, you cannot find Her.” Paleoceanography, v. 11, p. 267–275. v. 94, p. 6600–6605. Dickens, G. R., Castillo, M. M., and Walker, J. C. G., Kennedy, M. J., 1996, Stratigraphy, sedimentology, and ACKNOWLEDGMENTS 1997, A blast of gas in the latest Paleocene: Simulating isotopic geochemistry of Australian Neoproterozoic first-order effects of massive dissociation of oceanic postglacial cap dolostones: Deglaciation, δ13C excur- This work was supported by the methane hydrate: Geology, v. 25, p. 259–262. sions, and carbonate precipitation: Journal of Sedimen- Geological Survey of Namibia, University Evans, D. E., 1998, True polar wander, a supercontinen- tary Research, v. 66, p. 1050–1064. of Victoria, National Science and Engi- tal legacy: Earth and Planetary Science Letters (in press). Kennedy, M. J., Prave, A. R., and Hoffmann, K. H., neering Research Council of Canada, Har- Fairchild, I. J., 1993, Balmy shores and icy wastes: The 1997, A carbon isotopic record through a Neoprotero- paradox of carbonates associated with glacial deposits zoic glacial cycle: Geological Society of America vard University, University of Maryland, Abstracts with Programs, v. 29, p. A-196. and National Science Foundation. Guowei in Neoproterozoic times, in Wright, V. P., ed., Sedimen- tology review 1: Oxford, UK, Blackwell, p. 1–16. Kirschvink, J. L., 1992, Late Proterozoic low-latitude Hu, Adam Maloof, Tony Prave, and Gaddy Fisher, D., 1974, Some more remarks on polar wander- global glaciation: The snowball earth, in Schopf, J. W., Soffer made important field observations. ing: Journal of Geophysical Research: v. 79, and Klein, C., eds., The Proterozoic biosphere: New Sam Bowring gave permission to quote p. 4041–4045. York, Cambridge University Press, p. 51–52. the age of the tuff in the Ombombo Sub- Gold, T., 1955, Instability of the Earth’s axis of rotation: Kirschvink, J. L., Ripperdan, R. L., and Evans, D. A., Nature, v. 175, p. 526–529. 1997, Evidence for a large-scale reorganization of Early group. We are grateful for constructive Cambrian continental masses by inertial interchange and encouraging discussions with Sam Goldreich, P., and Toomre, A., 1969, Some remarks on true polar wander: Science, v. 277, p. 541–545. Bowring, John Edmond, Dave Evans, Brian polar wandering: Journal of Geophysical Research; v. 74, p. 2555–2567. Knoll, A. H., Hayes, J. M., Kaufman, A. J., Swett, K., and Farrell, Peggie Delaney, John Grotzinger, Lambert, I. B., 1986, Secular variations in carbon iso- John Hayes, Andy Knoll, John Marshall, Gough, D. O., 1981, Solar interior structure and lumi- tope ratios from Upper Proterozoic successions of Sval- nosity variations: Solar Physics, v. 74, p. 21–34. bard and East Greenland: Nature, v. 321, p. 832–838. Mike McElroy, Paul Myrow, and Dan Grotzinger, J. P., and Knoll, A. H., 1995, Anomalous Knoll, A. H., Bambach, R. K., Canfield, D. E., and Schrag. Critical reviews by Nick Christie- carbonate precipitates: Is the Precambrian the key to Grotzinger, J. P., 1996, Comparative Earth history and Blick, Tom Crowley, and Lee Kump helped the Permian?: Palaios, v. 10, p. 578–596. Late Permian mass extinction: Science, v. 273, us to improve the manuscript. Grotzinger, J. P., Bowring, S. A., Saylor, B. Z., and Kauf- p. 452–457. man, A. J., 1995, Biostratigraphic and geochronologic Kump, L. R., 1991, Interpreting carbon-isotope excur- constraints on early animal evolution: Science, v. 270, sions: Strangelove oceans: Geology, v. 19, p. 299–302. REFERENCES CITED p. 598–604. Laskar, J., Joutel, F., and Reboutel, P., 1993, Stabiliza- Agassiz, L. J. R., 1840, Études sur les glaciers: Neuchâtel, Hambrey, M. J., and Harland, W. B., 1981, Earth’s pre- tion of the Earth’s obliquity by the moon: Nature, France, Jent & Gassman. Pleistocene glacial record: Cambridge, UK, Cambridge v. 361, p. 615–617. Berner, R. A., 1989, Biogeochemical cycles of carbon University Press, 1004 p. Light, M. P. R., Maslanyi, M. P., Greenwood, R. J., and and sulfur and their effect on atmospheric oxygen over Harland, W. B., 1964, Critical evidence for a great infra- Banks, N. L., 1993, Seismic sequence stratigraphy and Phanerozoic time: Palaeogeography, Palaeoclimatology, Cambrian glaciation: Geologische Rundschau, v. 54, tectonics offshore Namibia, in Williams, G. D., and Palaeoecology (Global and Planetary Change Section), p. 45–61. Dobb, A., eds., Tectonics and sequence stratigraphy: v. 75, p. 97–122. Hegenberger, W., 1987, Gas escape structures in Pre- Geological Society of London Special Publication 71, Boulton, G. S., 1990, Sedimentary and sea-level changes cambrian peritidal carbonate rocks: Geological Survey p. 163–191. during glacial cycles and their control on glaciomarine of Namibia Communications, v. 3, p. 49–55. 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8 GSA TODAY, May 1998 Coastal Sediments ’99 A GSA Committee May Need You Conference Calls for Steve Stow, Chair, 1997 Committee on Committees Abstracts Abstracts are due May 11, 1998, for the Perhaps you feel that if you nominate someone for a GSA committee, your nomination Coastal Sediments ’99 conference to be goes into a black hole, or is lost among hundreds of other nominations submitted when held June 20–24, 1999, on Long Island, the Society annually calls for members to serve on committees, as it does in this issue New York. Scales of Coastal Sediment of GSA Today. And if you were to volunteer for a committee assignment, your offer Motion and Geomorphic Change is wouldn’t be taken seriously, would it? the theme of the conference; GSA is a co-sponsor. The reality is that there is no black hole, and every nomination for committee service is considered carefully. The address for submittal of abstracts (five paper copies) is: William G. The reality is also that since 1990, the number of volunteers for committee service has McDougal, Co-Chair, Coastal Sedi- dropped from 50 per year to an average of 30 and that the number of members nomi- ments ‘99, Dept. of Civil Engineering, nated for appointment has varied annually from a low of 16 in 1996 to a high of 75 in Oregon State University, Corvallis, OR 1993; the average is 39 per year. Since 1992, the number of appointees to GSA com- 97331-2302. For further information: mittees has been highly variable, from zero to more than 20. The 1997 Committee on Nicholas C. Kraus, USAE Waterways Committees, relying heavily on nominations and volunteers, selected 12 of the 29 vol- Experiment Station, Coastal & unteers and 12 of the 34 nominees for service on GSA committees. Hydraulics Lab. (CEWES-CC), For many reasons, it is not possible—or even advisable—to use only names of volunteers 3909 Halls Ferry Rd., Vicksburg, and nominees in making committee assignments. Many factors, including experience, MS 39180-6199, or http://www. geoscience discipline, geography, prior GSA experience, and minority representation, coastalsediments.org. go into the selection process. The Committee on Committees draws on names of indi- viduals considered but not selected by the previous committee, as well as its own per- sonal knowledge of qualified candidates, in getting a slate that is truly representative of Global Glaciations continued from p. 8 the GSA membership and qualified to perform the functions of the varied committees. It is a full day’s job (after a lot of preliminary work) to arrive at the final list of candidates of the Brazilian Orogeny: Precambrian Research, v. 79, to be presented to the GSA Council for approval, an indication of how carefully each p. 347–361. volunteer and each nominee are considered. Magaritz, M., 1989, 13C minima follow extinction events: A clue to faunal radiation: Geology, v. 17, If your name, volunteered or nominated, comes before the 1998 Committee on Com- p. 337–340. mittees and is not selected, don’t lose hope—try again next year. The simple fact that Marshall, H. G., Walker, J. C. G., and Kuhn, W. R., someone wants to devote some of his or her time to helping GSA, or the fact that one 1988, Long-term climate change and the geochemical cycle of carbon: Journal of Geophysical Research, v. 93, member feels strongly about nominating another, goes a long way in elevating that p. 791–801. person’s chance of being selected. McKenzie, D., 1978, Some remarks on the development of sedimentary basins: Earth and Planetary Science Let- ters, v. 40, p. 25–32. Graduate Students Encouraged to Volunteer! Meert, J. G., and Van der Voo., R., 1996, Paleomagnetic Graduate students are now eligible to serve on GSA Committees as full members. and 40Ar/39Ar study of the Sinyai dolerite, Kenya: Impli- All graduate students are encouraged to volunteer or nominate others for committee cations for assembly: Journal of Geology, v. 104, p. 131–142. service. Meert, J. G., Van der Voo, R., and Ayub, S., 1995, Paleo- magnetic investigation of the Neoproterozoic Gagwe lavas and Mbozi complex, Tanzania and the assembly of Gondwana: Precambrian Research, v. 74, p. 225–244. stratigraphic and petroleum exploration tool: American Wright, L., Williams, E. G., and Cloud, P., 1978, Algal Miller, R. McG., 1997, The Owambo basin of northern Association of Petroleum Geologists Bulletin, v. 64, and cryptalgal structures and platform environments of Namibia, in Selley, R. C., ed., African basins (Sedimen- p. 67–87. the late pre-Phanerozoic Noonday Dolomite, eastern California: Geological Society of America Bulletin, tary basins of the world, 3): Amsterdam, Elsevier, Sohl, L. E., 1997, Paleomagnetic and stratigraphic impli- v. 89, p. 321–333. p. 237–268. cations for the duration of low-latitude glaciation in the Mound, J. E., and Mitrovica, J. X., 1998, True polar late Neoproterozoic of Australia: Geological Society of Zachos, J. C., Arthur, M. A., and Dean, W. E., 1989, wander as a mechanism for second-order sea-level vari- America Abstracts with Programs, v. 29, p. A-195. Geochemical evidence for suppression of pelagic marine productivity at the /Tertiary ations: Science, v. 279, p. 534–537. Spero, H. J., Bijma, J., Lea, D. W., and Bemis, B. E., boundary: Nature, v. 337, p. 61–64. Park, J. K., 1997, Paleomagnetic evidence for low-lati- 1997, Effect of seawater carbonate concentration on tude glaciation during deposition of the Neoproterozoic foraminiferal carbon and oxygen isotopes: Nature, Manuscript received February 11, 1998; revision received Rapitan Group, Mackenzie Mountains, N.W.T., Canada: v. 390, p. 497–500. March 24, 1998; accepted March 24, 1998 ■ Canadian Journal of Earth Sciences, v. 34, p. 34–49. Stanistreet, I. G., Kukla, P. A., and Henry, G., 1991, Sed- Porada, H., Ahrendt, H., Behr, H.-J., and Weber, K., imentary response to a Late Proterozoic Wilson Cycle: 1983, The join of the coastal and intracontinental The Damara Orogen and Nama Foreland, Namibia: Journal of African Earth Sciences, v. 13, p. 141–156. branches of the Damara orogen, Namibia, in Martin, H., Each month, GSA Today features a short and Eder, F. W., eds., Intracontinental fold belts: Berlin, Torsvik, T. H., Lohmann, K. C., and Sturt, B. A., 1995, science article on current topics of gen- Springer-Verlag, p. 901–912. Vendian glaciations and their relation to the dispersal Rampino, M. R., 1994, Tillites, diamictites, and ballistic of Rodinia: Paleomagnetic constraints: Geology, v. 23, eral interest. For guidelines on submit- ejecta of large impacts: Journal of Geology, v. 102, p. 727–730. ting an article, contact either GSA Today p. 439–456. Trompette, R., 1997, Neoproterozoic (~600 Ma) aggrega- Science Editor: Roberts, J. D., 1976, Late Precambrian dolomites, Ven- tion of Western Gondwana: A tentative scenario: Pre- dian glaciation, and synchroneity of Vendian glacia- cambrian Research, v. 82, p. 101–112. S. M. Kay, Cornell University tions: Journal of Geology, v. 84, p. 47–63. Williams, G. E., 1975, Late Precambrian glacial climate (607)255-4701, fax 607-254-4780 Schmidt, P. W., and Williams, G. E., 1995, The Neopro- and the Earth’s obliquity: Geological Magazine, v. 112, [email protected] terozoic climatic paradox: Equatorial paleolatitude for p. 441–544. Marinoan glaciation near sea level in South Australia: Williams, G. E., 1993, History of the Earth’s obliquity: M. F. Miller, Vanderbilt University Earth and Planetary Science Letters, v. 134, p. 107–124. Earth-Science Reviews, v. 34, p. 1–45. (615) 322-3528, fax 615-322-2137 Scholle, P. A., and Arthur, M. A., 1980, Carbon isotope [email protected] fluctuations in Cretaceous pelagic limestones: Potential

GSA TODAY, May 1998 9 He also introduced Bowen to some of the possible causes of differentiation, such as dif- fusion, fractional crystallization, crystal seg- regation, gaseous transfer, immiscibility (liquation), and assimilation. Probably Charles H. Warren imbued Bowen with the Norman L. Bowen: The principles of physical chemistry as applied to mineralogical and petrological problems. Experimental Approach It was clear that he had already focused on igneous differentiation and the principles to Petrology of physical chemistry.

H. S. Yoder, Jr., Geophysical Laboratory, Carnegie Institution The Experimental Experience of Washington, Washington, DC 20015, [email protected] In 1910, at the suggestion of T. A. Jag- gar, then at MIT, Bowen applied to the Geo- physical Laboratory at the Carnegie Institu- tion of Washington to do an experimental he greatest petrologist of the 20th crops was done under a blanket of mosquitoes study related to a geological field problem century is clearly Norman Levi and black flies. Bowen could use an axe and for partial fulfillment of the requirements of Bowen (1887–1956). He promoted tump line, make pace-and-compass surveys, the Ph.D. As the laboratory’s first predoc- the solution of petrological field and cook. In the course of his mapping, he toral Fellow, he was assigned the “nephelite Tproblems by the application of principles became interested in the differentiation of problem,” a favorite topic of J. P. Iddings. At deduced from simple phase diagrams of the diabase. that time, most of the experimental tech- end members of common rock-forming niques for high temperatures used today minerals, thereby providing a quantitative Courses Chosen were all in their early stages of develop- approach to a field previously concerned As a result of his field experiences, ment. The controllers for the high-tempera- only with observation and classification. when he returned to Queen’s University, ture furnaces were very large street-car-type Despite his quiet personality, subdued pre- Bowen registered in the School of Mining, banks of resistor coils; platinum-rhodium sentations, droll sense of humor, and even taking mineralogy and geology. After two thermocouples had just been calibrated to his small stature, he was a giant. more field seasons around Lake Abitibi and 1755 °C by Day and Sosman (1911); the Gowganda Lake, again paying attention to quenching method had just been invented Work and Play the diabases, he won a prize of $25 and the by Shepherd, Rankin, and Wright (1909). As a youth, Bowen helped his father in President’s gold medal from the Canadian Wright (1910) had perfected a new petro- the family bakery, driving the delivery rig— Mining Institute for the best paper submit- graphic microscope for examining fine- an experience that resulted in his enduring ted by a student: “Diabase and aplite of the grained synthetic preparations. Particularly distrust of horses. Winters were spent ice cobalt-silver area.” (See 1956 edition of important was the development of a calcu- skating, and during the summer months he Bowen [1928] for references to his pub- lation scheme for translating the chemical became a strong breast-stroke swimmer and lished works.) Trained in the Canadian analyses of rocks, whether crystalline or took part in races. He sang in the choir of bush on the myriad of variables in natural glassy, into a set of end-member minerals, the local Anglican church and is alleged to geological processes, he had rapidly the CIPW normative system (Cross et al., have had a fine tenor voice. absorbed the principles of geology and 1902), that could be simplified for labora- chemistry. On graduation in tory experimentation. In addition, the the- The Field Experience 1909, he won a London Exhi- ory of solid solutions had been laid out by Public schools in bition of 1851 Scholarship, H. W. Bakhuis Roozeboom (1901). In short, Kingston, Ontario, had pre- which gave him the opportu- Bowen arrived at a most opportune time pared him for college entrance nity to continue on in gradu- to do the nepheline-anorthite system—all examinations at Queen’s Uni- ate school. the tools and theory were in hand. The versity. Even though registered nepheline-anorthite diagram was deter- in the arts course with the Charismatic Teachers mined with considerable efficiency with 17 intent of becoming a teacher, He was first attracted to different mixtures and 55 quenching experi- Bowen had the urge, as many Norway because of J. H. L. ments under the tutelage of E. S. Shepherd young people do, to see new Vogt’s (1903–1904) book, Die and F. E. Wright. That simple system, the and alluring country and to Silikatschmelzlösungen and by first example found in silicates of solid solu- earn some money. He joined W. C. Brøgger, who had an Ontario Bureau of Mines applied physicochemical prin- geological mapping party to ciples developed in the inves- Larder Lake under the leader- tigation of slags to the prob- ship of R. W. Brock. Brock, lem of differentiation. Bowen who was an outstanding per- was discouraged, however, The sonality and eventually from going to Norway because courtship became Director of the Geo- of the language barrier and of N. L. logical Survey of Canada, because Brøgger was too busy Bowen had so much confidence in with legislative duties. Instead, and Mary Bowen’s inherent abilities, in Bowen went to MIT to study Lamont, a medical addition to his skills for sur- under the sparkling and student in viving in the bush, that he left charismatic teacher Reginald Boston. the young man to carry out A. Daly, who indoctrinated the work alone! Travel in the Norman L. Bowen on his him with the idea that basaltic bush was by canoe, and first job involving land liquid was a primary traversing in search of out- surveying. and all others were derivative.

10 GSA TODAY, May 1998 method, even though they recognized the above sequence until a satisfactory solution system as one of the Roozeboom theoreti- is achieved, recognizing that any new cally possible types, with continuous solid observation or inconsistency may initiate solution containing neither a maximum the process again. nor minimum. With the quenching method and run times of only 1/2–2 hours, Successful Philosophy Bowen was able to generate the entire pla- After half a century, it is clear that his gioclase diagram, well documented with philosophy had been successful even later studies. It provided the basis for his though new interpretations of the details subsequent views on magma differentiation were required (Yoder, 1979). Bowen’s and crystal fractionation, both old ideas legacy, in addition to the many accurate (Scrope, 1825; Becker, 1897) but lacking and precise phase diagrams of the end experimental demonstration. members of common rock-forming miner- als, is the construction of an experimental A New Integrated Approach and theoretical basis for the interpretation Several alternatives for the processes and documentation of the diversity of leading to magma diversity had already igneous and metamorphic rocks. been presented and explicitly summarized by Iddings (1892). But Bowen set out his References Cited prejudices forcefully and clearly in 1915 in Becker, G. F., 1897, Fractional crystallization of rocks: American Journal of Science, ser. 4, p. 257–261. two papers after studying only two more, The plagioclase phase diagram, with temperature Bowen, N. L., 1928, The evolution of the igneous rocks: in °C and the seven new synthetic and two natural yet most critical, phase diagrams illustrat- Princeton, New Jersey, Princeton University Press, anorthite-albite compositions studied, indicating ing the reaction principle. One paper, “The 334 p.; second edition, 1956, New York, Dover. the liquidus (upper curve) and solidus. The melt- later stages of the evolution of igneous Cross, C. W., Iddings, J. P., Pirsson, L. V., and Washing- ing point of anorthite was already well established rocks,” provided a flexible, broad theory ton, H. S., 1902, A quantitative chemico-mineralogical and used as a point for thermocouple calibration. classification and nomenclature of igneous rocks: Jour- based on quantitative experimental obser- nal of Geology, v. 10, p. 555–690. vations that he defended with rigorous Day, A. L., and Sosman, R. B., 1911, High temperature argumentation. As a result of his incredible gas thermometry: Carnegie Institution of Washington perceptiveness and intuition, Bowen had Publication 157, 129 p. tion combined with polymorphism, gener- integrated all the new experimental meth- Day, A. L., Allen, E. T., and Iddings, J. P,. 1905, The iso- ated in Bowen’s mind a much larger picture. morphism and thermal properties of the feldspars: ods, physicochemical theory, and field While writing his thesis he also managed to Carnegie Institution of Washington Publication 31, 95 p. observations into a unified new approach produce in 1912 a paper of lasting value, Iddings, J. P., 1892, The origin of igneous rocks: Philo- to petrology. It was his clarity of presenta- sophical Society of Washington Bulletin, v. 12, “The order of crystallization in igneous p. 89–213. tion, documentation of principles with rocks.” With this publication at age 25, experimental demonstrations, and applica- Roozeboom, H. W. Bakhuis, 1901, Die Heterogenen Bowen had introduced the precursor to a Gleichgewichte vom Standpunkte der Phasenlehre: tion to specific field problems that eventu- Braunschweig, Germany, Friedrich Vieweg und Sohn, major change in the approach to petrology. ally made his 1928 book The Evolution of the Vol. I—221 p.; Vol. II, 3 parts—467 p. (1904); 226 p. (1918); 199 p. (1918); Vol. III, 2 parts—313 p. (1911); Igneous Rocks, the handbook for petrologists Career Decision 348 p. (1913). worldwide. It was with some reluctance In the summer of 1911 Bowen was in Scrope, G. P., 1825, Consideration on volcanoes: Lon- that field geologists eventually accepted don, W. Phillips, 270 p. the field again with Reginald Daly, surveying Bowen’s philosophy as leading to the most Shepherd, E. S., Rankin, G. A., and Wright, F. F., 1909, the Shuswap terrane of British Columbia, satisfactory interpretation of the facts as The binary system of alumina with silica, lime and famous for its crosscutting and magnesia: American Journal of Science, ser. 4, v. 28, they were perceived by geologists: (1) recog- wholesale injection. In spite of his absences p. 293–333. nition of a set of field observations that from Boston, he managed to court Mary Vogt, J. H. L., 1903–1904, Die Silikatschmelzlösungen appear to be related; (2) simplification of mit besonderer Rucksicht auf die mineralbildung und Lamont, and they were married on October these relations into a set of laboratory die Schmelzpunkt-Erniedrigung: Christiana, Norway, 3, 1911. Upon graduation from MIT on June Jacob Dybwad, 235 p. experiments analogous to the conditions 4, 1912, he had offers from Jaggar, then at Wright, F. E., 1910, A new petrographic microscope: believed to have existed in nature; (3) exe- the Volcano Observatory in Hawaii, for a American Journal of Science, ser. 4, v. 29, p. 407–414. cution of those experiments in an unam- post in economic geology at Tucson, for a Yoder, H. S., Jr., 1979, The evolution of the igneous biguous manner; (4) application of the rocks: Fiftieth anniversary perspectives: Princeton, New position at the Geological Survey of Canada, principles derived from the experimental Jersey, Princeton University Press, 588 p. and for the job of assistant petrologist at the results to specific field occurrences; (5) re- Yoder, H. S., Jr., 1992, Norman L. Bowen (1887–1956), Geophysical Laboratory. After another field MIT class of 1912, First predoctoral Fellow of the Geo- examination of the field relations and test- season in British Columbia, in charge of his physical laboratory: Earth Sciences History, v. 11, ing the new principles with additional p. 45–55. ■ own field party, he decided to join the observations; and (6) reiteration of the Geophysical Laboratory staff, arriving September 1, 1912 (Yoder, 1992).

Critical Mineral Systems Walcott Biography To Be Published Plagioclase is the most abundant mineral in GSA original Fellow and 13th president Charles Doolittle Walcott is the subject of a biography Earth’s crust, so Bowen next undertook a by Ellis L. Yochelson; it will be published in June. Yochelson’s Rock Star profile of Walcott, a study of the two-component system albite- famous paleobiologist and biostratigrapher, was in the January 1996 issue of GSA Today. The anorthite. That system, studied earlier by book covers Walcott’s life from birth in 1850 until 1907, when he resigned as third director of Day, Allen, and Iddings (1905), was the the U.S. Geological Survey to become secretary of the Smithsonian Institution. subject of the first official publication of the Geophysical Laboratory. They had been The book is available from Kent State University Press, P.O. Box 5190, Kent, OH 44242 able to determine the melting temperature (not available through GSA Publication Sales). Charles Doolittle Walcott, Paleontologist is available at the prepublication price of $40, including postage and handling, for a limited only from An100 to An26.1 Ab73.9. Kinetic problems prohibited their measuring the time (after July 31, 1998, the price will be $53). All orders must include payment and the solidus temperature with the cooling-curve title of the book; Ohio residents add 6.25% sales tax.

GSA TODAY, May 1998 11 SAGE REMARKS

Edward E. “Dr. Ed” Geary, Director of Educational Programs GSA Educational Programs: What Are We Doing and Where Does the Money Come From?

Last year I used this column (GSA Today, February 1997) to high-energy characters, reinforce the key learning concepts of each look back at the evolution of GSA’s educational programs over lesson through a set of short, engaging animations. Students use the past five years. This year I want to use this opportunity to real data in carrying out their GET-IT investigations, and at the update you on the status of some of our current programs and let same time they develop their mathematics and writing skills. you know how we fund our education and outreach activities. In 1997, GSA, in collaboration with Cypress College and the Please read this article, let us know what you think of our efforts, Space Science Institute, conducted two summer workshops, each and contact us if you would like to learn more about or become two weeks long, for the Earth and Space Science Techno- more involved in geoscience education activities. logical Education Project (ESSTEP). This four-year project brings together teams of undergraduate and secondary faculty with What Are We Doing? professional societies, businesses, and government agencies in a partnership to provide faculty in grades 8 through 14 with Programs (1) hands-on experience in state-of-the-art data acquisition, manip- The Partners for Education Program (PEP) promotes and ulation, and presentation technologies for the earth and space sci- supports professional partnerships between geoscientists and K–12 ences; (2) innovative strategies for using technology in classrooms educators both in formal and informal settings. In 1997, PEP was and laboratories; (3) internship opportunities in earth and space sci- busy: ence technology fields; and (4) improved access to a wide variety of • Growing! PEP now includes 1,700 volunteers in all 50 states and technology-based education resources. Over 40 geoscience, geogra- more than 60 international associates; these Partners volunteer in phy, biology, mathematics, astronomy, and technology faculty par- formal classroom settings and in a wide variety of informal set- ticipated in the 1997 workshops. Faculty and staff continue to work tings such as museums, parks, science fairs, special science events, together during the 1997–1998 school year, on project goals via and field trips, to help share the excitement of the geosciences. Tapped In, an on-line professional development tool that supports • Expanding! Although we’re growing by the day, at last count 470 both synchronous and asynchronous forms of communication. The PEP e-mail Partners and 97 PEP Experts are also signed up to help first-year project participants will come back to Boulder in 1998 to answer questions in their own specialties for each other, students, share their initial classroom ESSTEP experiences, advance their tech- other educators, and the public. nological knowledge and skills, and develop strategies to share their • Reaching out! Through PEP, we are collaborating with a variety of ESSTEP experiences and materials with others. The next two ESSTEP local, regional, and national groups to reach a broader segment of workshops, for 40 new faculty, will be held July 6–18 in Cypress, the public. For example, 10 PEP members volunteered their California and July 27–August 8, 1998, in Boulder, Colorado. expertise at the Geology Merit Badge booth at the 1997 Boy Scout ESSTEP and GET-IT are supported in part by grants from the Jamboree. We are also expanding our outreach through programs National Science Foundation. such as Rooted in Rock (in collaboration with the National Park Service) and GeoArt (in collaboration with local governmental Meetings and Workshops agencies) both described in the Informal Education section below. The K–16 Education Program at the 1997 GSA Annual Meet- • Supporting! Our second annual Project WET (Water Education for ing in Salt Lake City was outstanding in both the variety of Teachers) workshop at the 1997 GSA Annual Meeting in Salt Lake offerings and the quality of presentations. Workshops were offered City drew a lively crowd of scientists, classroom educators, infor- on the solar system, marine geology, the fossil record, Project WET, mal science educators, and graduate students, all eager to refine mapping and spatial analysis, grant writing, and effective teaching. their professional partnering skills. We offered support to scien- Educational symposia and theme sessions ranged from “Engaging tist-teacher workshops hosted by PEP members. We also offer the National Science Education Standards” to “Earth System Science membership incentives such as low-cost U.S. Geological Survey Laboratories for Introductory Undergraduate Courses” to “Earth Sci- maps and a listing of all state science supervisors and how to ence Education for Pre-Service Teachers.” The third Rock and Min- reach them. We are collecting an anthology of PEP members’ eral Raffle and the fifth Earth Science Share-a-Thon, co-sponsored favorite “educational geoscience places.” by the National Earth Science Teachers Association (NESTA), • Communicating! Our quarterly PEP News keeps PEP members up attracted many curious scientists, students, and teachers. Several to date on geoscience educational resources, activities, opportuni- workshops and field trips for K–16 educators and scientists were also ties, and each other’s experiences. We update and distribute our held at GSA’s 1997 Section meetings. In 1997, we also conducted national PEP Membership Directory each spring. “standards-based” workshops on and ESSTEP at • Appreciating! We are happy to award year-end certificates to the Western Regional Meeting of the National Science Teachers express our thanks to our wonderful PEP members. Association. The Geological Education Through Intelligent Tutors Informal Science Education Programs (GET-IT) project is now in its third year. GSA, in collaboration with A major advancement for the Colorado Rock Park Project Cambrian Systems Incorporated, is currently beta testing an interac- in 1997 was the selection of a location for the two-acre outdoor tive, multi-media, geoscience CD-ROM for middle school students. exhibit. After consideration of approximately 15 different sites, we The CD-ROM introduces students to scientific investigations of have chosen a site in Fort Collins, a city within the Denver–Front Earth through visits to a virtual Geoscience Museum. The focus of Range metropolitan area, approximately 50 miles north of Denver. student investigations is energy transfer in the Earth system. Stu- The site is easily accessible and will be part of a new outdoor Envi- dents visiting the museum can conduct rock-melting experiments, ronmental Learning Center. The Fort Collins site will also include a learn about pressure, temperature, and volume relationships, study new visitor center with classrooms, nature trails, interpretive pro- historic volcanic eruptions and make predictions about future erup- grams, and tourist information. This chosen location also brings tions, analyze hurricane storm tracks, and a variety of other activi- dynamic partners into the Rock Park project: the city of Fort ties. When the students finish a series of investigations and experi- Collins, Colorado State University, Colorado State Parks, and the ments, Throbby the Brain and Professor Exactamundo, two

12 GSA TODAY, May 1998 Fort Collins Convention and Visitors Bureau. As part of developing mote K–12 geoscience education partnering between geoscientists the Rock Park from a concept to a more detailed plan, GSA has fos- and educators. tered many new collaborations with industry, state government • Collaborating with groups such as the American Association of offices, and other Colorado educational institutions. Project devel- Petroleum Geologists, the Big Horn Basin Foundation, the opment, sample collection, and fund-raising will be the focus of the Alabama Geological Survey, and many more to support PEP Rock Park activities in 1998. members’ efforts in a wide array of settings, from classrooms to Rooted in Rock is a proposed five-year initiative to increase scouting groups to paleontology workshops for teachers to a mul- geologic and earth systems interpretation in the national parks. tistate excursion integrating geology, botany, and cultural history Rooted in Rock will serve visitors with: (1) current, accurate geologic for Puerto Rican university and K–12 educators, and much more. information informed by relevant research; (2) geologic information • Strengthening our collaboration with the National Park Service and interpretation directly tied to the features and processes observ- and initiating programs that will bring improved and expanded able in the park; (3) interpretation that connects geology with other geologic interpretation to national park visitors. natural and human systems; and (4) interactions with park staff • Strengthening communications and cooperation with the Ameri- who are well informed on the park’s geology and how it relates to can Indian Science and Engineering Society, also headquartered the park’s other natural and human systems. A funding proposal for in Boulder. Rooted in Rock was submitted, in cooperation with the Geologic • Preliminary planning with the Mineralogical Society of America, Resource Division of the National Park Service, to the National Sci- the Geochemical Society, and the USGS to develop Web-based ence Foundation in November 1997. We are also pursuing other learning modules for high school students and teachers. options for funding the program. • Meeting with AGI, AGU, NAGT, and NESTA representatives to GeoArt will help people examine geologic information and discuss concerns and issues in geoscience education outreach. concepts through art. The program builds on common ground • Advising the USGS on development of teacher-support materials between art and geology, such as the strong use of observation and for their Dynamic Planet Map project. interpretation in both fields, and the importance of frameworks Information Dissemination such as pattern, scale, and change in both fields. Participants will During 1997 GSA Educational Programs handled 1,350 produce their own artwork while they learn about local geologic requests for information from students, teachers, scientists, and features and processes. A materials grant of $200 from the Boulder organizations on topics ranging from earthquakes, crystals, and County (Colorado) Commissioners funded two GeoArt training National Science Education Standards, to careers in the geosciences, workshops in March 1998, for interpretive staff and volunteers for internship opportunities, and awards. In 1997, we continued to parks and open-space properties in GSA’s headquarters community. offer education and career information request forms that can be The workshop participants will choose from several opportunities to accessed and submitted electronically via the GSA World Wide Web present their own GeoArt sessions for the public soon after their site. training in order to gain experience and comfort with GeoArt tech- niques. Future plans include models for disseminating GeoArt into 1997 Educational Programs Staff other communities and into informal and formal educational set- All of these activities would not have been possible without the tings such as youth groups, adult learning, and K–12 classrooms. support of our wonderful staff. Special thanks to Beth Baker, Beth Ann Brown, Holly Devaul, Vicki Harsh (now at U.S. West in Den- Collaborative Efforts ver), Liz Knapp, Gwenevere McNally, Barb Mieras, and Van Schoales SAGE has been and continues to be very active in collaborative (now headmaster at Jarrow Montessori school in Boulder). efforts with other organizations. In 1997 SAGE collaborations included: Where Does The Money Come From? • Representation on the Program for the Advancement of Geo- Funding for our education and outreach activities comes from science Education (PAGE), American Geological Institute (AGI), a variety of sources (see pie chart). These sources include govern- and Project Learn II Advisory Committees. ment agencies such as the National Science Foundation, corporate • Continued participation in Professional Career Pathways in the and private foundations, members, and GSA’s operating budget. Geosciences, a careers project coordinated by AGI and supported As you can see, in 1997, our total educational program budget was by the Alfred P. Sloan Foundation. $837,000. Of this total, 68% of our funding came from the National • Working with CONNECT, the Colorado statewide systemic initia- Science Foundation, 17% came from corporate and private founda- tive in mathematics and science. tions and member gifts, and 15% came from GSA’s operating • Participation in the Second International Conference on Geo- budget. science Education, cosponsored by the Coalition for Earth Science It is worth noting that GSA now spends less of its operating Education (CESE). budget on educational programs than it did in 1992, the first full • Financial support of the National Association of Geoscience year of educational program activities. At the same time, the overall Teachers Outstanding Earth Science Teachers Award. scope of our educational activities has grown dramatically. Our edu- • Working with national environmental education programs such cation budget is more than five times what it was in 1992 and our as Project WET, Project WILD, and Project Learning Tree to pro- staff has tripled in size. Our reliance on outside funding gives us both a sense of pride and concern. We are proud that the vast majority of our programs and staff are funded by non-GSA sources. How GSA Educational Programs Are Funded We feel that we are making good use of GSA’s contributions to edu- 1997 Total = $837,000 cation activities and making your dollars go farther. However, GSA owing to our reliance on outside funding for many of our programs, 15% $130,000 the future of some programs, such as PEP, are uncertain as outside National funding sources disappear. Science In 1998 we will be integrating our Educational (SAGE) and Foundation Donations from Institute for Environmental Education (IEE) program departments Grants GSA Members to provide a more seamless set of outreach programs for students, 68% and Friends teachers, GSA members, policy makers, and the public. We will also $568,000 17% be assessing the value of individual projects and activities, dis- $139,000 cussing issues of long-term program sustainability, and aligning our program goals and objectives with the new GSA strategic plan, currently under development. ■

GSA TODAY, May 1998 13 greatly value and rely on the expertise of LETTERS independent geologists in accomplishing the goals of the program. The National Cooperative Geologic and trade-offs between plant production, N Mapping Program has accomplished much and CO2 fertilization, decomposition, and since it was first passed by the Congress in CO2 Source or Sink fire, and how do the interactions change 1992 and unanimously reauthorized in In reference to the report from David J. under changing land management and cli- 1997. But to accomplish the task of map- Verardo, “Forests as Carbon Sinks” (GSA mate? These questions are unresolved in the ping the nation, the program requires full Today, v. 8, no. 2, February 1998), it is heart- scientific community, and the solutions are funding. The products of the program can ening to see a GSA congressional fellow get- likely to be as complex as the systems. stand on their own merits, but without ting geology into this important topic. I political action from both the geological Jennifer Harden would point out, however, that while the and map-user communities there is only U.S. Geological Survey process of CO fixation by photosynthesis is a small chance that full funding will be 2 Menlo Park, CA 94025 a no-brainer, net carbon storage (sink/source achieved. I urge you to contact your con- for the atmosphere) is the balance of photo- gressional representatives and urge them G. K. Gilbert synthesis/production and decomposition/ to fully fund the National Cooperative The accolade for Rock Star G. K. Gilbert burning. In a recent paper in Science Geologic Mapping Program. by Bourgeois (GSA Today, February 1998, (Goulden et al., v. 279, p. 214, January 9, p. 16–17) expressed beautifully what an Robert G. Marvinney 1998), a diverse team of scientists discov- exceptional thinker and doer Gilbert was.... Maine Department of Conservation ered an unexpected conundrum: even a Gilbert's 1896 publication on the Augusta, ME 04333-0022 boreal forest with vast amounts of biomass underground water of the Arkansas and soil carbon can become a CO source in 2 in eastern Colorado devoted equal space to Ediacara Biota some years and a CO sink in other years. 2 stratigraphy and underground water. "The Ediacara Biota" [GSA Today, Febru- The underlying cause for the C imbalance Although plagued by too little information, ary 1998, p. 1–6] was an outstanding article! in this system was oxidative decomposition; he courageously put lines on a map show- It covers a subject quite outside my field the soil carbon flux was found to com- ing depth to water, saying "I confess that I (petroleum), but one in which I have always pletely offset plant production in years have drawn this map with great reluctance" been interested. Guy Narbonne's review was that proved favorable to decomposition. (Agnew in E. Yochelson, The Scientific Ideas understandable, comprehensive, well illus- Although the permafrost was likely a key of G. K. Gilbert, GSA Special Paper 183, trated, and greatly appreciated. Articles like player in the CO release in this study, 2 p. 81–91). He recommended experimental that have me looking forward to my issues many forests suffer the same fate: all but the borings, as his report was a practical one of GSA Today. youngest of landforms (Harden et al., Sci- that was intended for local residents (non- ence, v. 258, p. 1921) have enough soil car- Duncan Goldthwaite geologists). bon to contribute significant amounts of Metairie, LA 70006-1032 ... Gilbert was a true Rock Star—a CO from decomposition. Although the 2 century before we rediscovered the value coarse wood growing in trees is a temporary Tribute to John Mann of making our geologic reports speak to C sink, the wood entering the soil becomes As one of Southern California’s most nongeologists as well as to the choir. a C source within decades of tree death. senior hydrogeologists, Dr. John Mann [see Additionally, all forests and their carbon Allen F. Agnew GSA Today, January 1998, p. 1; April 1998, reserves are vulnerable to fire—anywhere Corvallis, OR 97330 p. 11] brought a valuable perspective to the from 20% to 80% of biomass is lost to students he taught, the clients he served, stand-killing fires; therefore depending on Mapping and the issues at hand. His teaching skills recurrence times and moisture-dependent As the director of a state geological were often helpful when complex ground- fire losses, the apparent C sink term is survey I am pleased to see the support for water conditions needed to be understood— reduced considerably over any reasonable detailed geologic mapping expressed by such as comparing ground-water flow veloc- spatial scale. To further complicate the pic- independent geologists such as John Tram- ity to the speed of a snail (we all have seen ture, the fire and decomposition terms are mell (GSA Today, February 1998, p. 14) in the “tortuosity” of snail tracks). Only with inexorably tied to the very climatic trends his comment on the letter by Rowley, the rich experience Dr. Mann had gained that we strive to mitigate. Dixon, and Stevens (GSA Today, October could one be able to give appropriate assess- Under what conditions would we 1997, p. 17–19) which describes the ments of ground-water availablility during ≥ expect a long-lived ( 100 year) sink of CO2? National Cooperative Geologic Mapping reconnaissance level investigations. He had (1) Retardation of decomposition: submer- Program. From his comments, I surmise a healthy respect for good data and thor- gence, freezing, burial, and high lignin con- that Trammell would be more supportive ough analytical procedures, while not rely- tents work well; (2) landscapes where plant of this program if some of the funds were ing too much on simulations where unspo- production is greater than decomposition, a used to support contract geologists such as ken assumptions control conclusions. His situation that occurs on newly created land- himself to conduct geologic mapping. “safe yield” treatise, prepared over twenty scapes such as fresh deposits or recent land- Since its inception, the Maine Geo- years ago, is still an excellent reference. slides. Of course, the fate of the eroded car- logical Survey has received approximately John was a pleasure to work with. bon must also be considered for an accurate $139,000 in support through the program I enjoyed engaging in dialogue on critical portrayal of the net C balance. Under condi- for geologic mapping in Maine. Of that resource issues as well as comparing notes tion 1, the creation of wetlands would foster amount, about $99,000 (over 70%) has on our travel experiences. His and Carol’s carbon sequestration, but possibly at low gone to contract mappers (consultants, col- travels yielded many beautiful Christmas production rates unless fertilized. Under lege professors, and students). Many other cards. condition 2, forests will work as temporary state geological surveys can produce similar We will miss him. His work will stand C sinks, but longer-term solutions reside in statistics. Those of us involved in the pro- the test of time. soil conditions less favorable (wet, cold) gram recognize that the monumental task Timothy S. Cleath to healthy forests. of geologically mapping the nation in detail Cleath & Associates Thus, the conundrum continues for cannot be accomplished solely with the San Luis Obispo, California ■ terrestrial ecology: what are the interactions capabilities of government agencies. We

14 GSA TODAY, May 1998 Death on the High Seas not supersede common laws or state law remedies. The bill would retroactively David J. Verardo, 1997–1998 GSA Congressional Science Fellow amend DOHSA to remove the arbitrary dis- tinction between remedies available for aviation disasters occurring within three miles of the coast (currently subject to It isn’t always about science policy. large wave rolled state tort law) and those occurring outside In the pre-dawn hours of Novem- the raft and the the three mile limit (currently subject to ber 24, 1995, in storm-tossed seas north- family lost hold of the painter. The wife DOHSA). As introduced, however, S.943 east of New Zealand’s North Island, a quickly regained her grip but her daughter would create another arbitrary distinction Korean freighter rammed and sank a U.S.- and husband drifted away. They tried to in the treatment of wrongful death actions registered 47-foot cutter-rigged sloop. The regain the raft but were unable. Both between aviation and maritime disaster vessel sank in less than 60 seconds. Aboard drowned within her sight. claims. In the bizarre, though not incredi- the yacht were an American couple and At 2000 hours on November 25, after ble, instance of an aviation disaster occur- their two young children. Forty-two hours 42 hours at sea, the life raft and its sole ring on the high seas (i.e., beyond three later, the sloop’s inflatable raft washed passenger washed ashore on rocks near miles of the coast) that also causes loss of ashore carrying a lone, badly injured Cape Brett. While scrambling onto the life onboard a recreational vessel, the rela- survivor. rocks, the woman slipped and fractured tives of those traveling on the plane would This story began in 1994 when the two vertebrae. Paralyzed from the waist be subject to state tort and able to secure couple, along with their nine-year-old son down, she crawled onto the beach. Several nonpecuniary damages, while those and seven-year-old daughter, went on an hours later she was rescued when search onboard the recreational vessel would be extended break from their careers to sail aircraft, alerted by overdue notices from restricted to DOHSA. Discussions in the throughout the Pacific. At 1200 hours local other vessels in the flotilla, spotted the raft. Senate Commerce, Science, and Trans- time on November 16, 1995, the yacht left Her suffering was not over, though. Now, portation Committee may remove these Nuku’alofa, Tonga, on a passage to the Bay bureaucracy would torment her. arbitrary distinctions and create a more of Islands, New Zealand. She was part of When the sole survivor of the ship- inclusive law that allows recovery of dam- a flotilla of eight sailing vessels that were wrecked family sought economic recovery ages for victims of accidents that occur at headed south to avoid the approaching from the owners of the Korean vessel, she sea. Although money does not bring back typhoon season. The passage would take was stymied because of an arcane U.S. law the dead, it does help survivors endure. eight days. The forecast on November 23 called the Death on the High Seas Act To date, the surviving woman’s case has called for deteriorating weather with gusty (DOHSA). The original law was enacted in not come to trial, and she remains emo- winds and squalls. With the mainsail 1920 to allow recovery for the wrongful tionally and physically disabled by her doused and the staysail rigged, the sloop death of seafarers occurring outside the experiences and injuries. sailed well, making six knots and barely three-mile territorial waters of the United This case provides a working example rolling. There were scattered showers, States. The right to recover is limited to the of the intricacies of public policy formula- visibility between five and seven miles, decedent’s wife, husband, parent, child, or tion. What is a solution for one group is a and no moon. dependent relative against a vessel, person, problem for another. More often than not, At 0200, the wife relieved her husband or corporation. This right is further limited public policy, like science, changes at the on watch. About 15 minutes later, a large to monetary damages such as economic edges, incrementally. Only occasionally shape loomed out of the rain and, in a losses suffered as a result of the death, loss does a comprehensive shift occur in core series of bone-jarring hits, sealed the ves- of services, loss of inheritance, and funeral values or conventional wisdom as a result sel’s fate. Within seconds, the vessel’s cabin expenses. Recovery for pain and suffering, of a single event or discovery. If you filled with water. The wife, who had been mental anguish, or punitive damages is not believe that the goal of government is to knocked to the deck, was trying to regain allowed. The U.S. Senate is now consider- protect and improve the life of its citizens, her footing when her husband and daugh- ing legislation (i.e., S.943) to amend then stark case histories provide the basis ter emerged from the cabin below. Those DOHSA; this was prompted not by ship- for action. Creating public policy is not a on deck abandoned the stricken vessel for wrecks, but by the 1996 crash of TWA clean, linear process. As Theodore Roo- the inflated raft trailing astern on a 15-foot Flight 800 off the coast of Long Island, sevelt remarked, “From the very beginning, sea-painter line. The wife and daughter New York. our people have combined practical capac- climbed aboard first; the father tried to res- The application of DOHSA to aviation ity for affairs with power of devotion to an cue his son below deck but flooding seas disasters began with a court case in 1972 ideal. The lack of either quality would have forced him back to the raft. The sloop involving the crash of a corporate jet into rendered the other of small value.” Win- slipped beneath the waves and left the the waters of Lake Erie; the jet had struck a ning or losing on the policy front is often three in stunned silence. Their anguish was flock of gulls upon takeoff. In that case, the due less to persuasive argument than to interrupted moments later when a wave court declined to apply DOHSA because it the sheer breadth of competing interests capsized their life raft. The family managed ruled that the flight was essentially land- across the social landscape. ■ to right the raft only to have it overturned based, even though the crash occurred in again by another wave. This occurred navigable waters. In a footnote to the deci- Dave Verardo, 1997–1998 GSA Congressional repeatedly, so they decided to leave the raft sion, however, the court stated that a Science Fellow, serves on the staff of Senator Ron inverted and hold fast to the painter. At wrongful death action stemming from an Wyden (D—OR). This one-year fellowship is sup- one point during this desperate struggle, a aviation disaster, occurring beyond a mar- ported by GSA and by the U.S. Geological Survey, large vessel’s navigational lights were rec- itime league (e.g., three miles) from the Department of the Interior, under Assistance Award ognized moving away from their position. shore of any state, could be prosecuted No. 1434-HQ-97-GR-03188. The views and conclu- The three survivors held on for their under the provisions of DOHSA. Subse- sions contained in this article are those of the author lives. Hours passed. Though the water was quent cases involving aviation accidents and should not be interpreted as necessarily repre- 68° F, the relative warmth merely slowed have ruled DOHSA applicable. senting the official policies, either expressed or implied, of the U.S. government or GSA. You can the weakening effects of hypothermia. The The bill before the U.S. Senate speci- contact Verardo by mail at 717 Hart Senate Build- morning of November 24 saw a gray dawn fies that remedies provided under DOHSA ing, Washington, DC 20510, by phone at (202) with winds blowing at 40 knots and seas that are applicable to aviation accidents 224-3430, or by e-mail at david_verardo@ running 14 feet. At about 1100 hours, a occurring on or after January 1, 1995, shall wyden.senate.gov.

GSA TODAY, May 1998 15 PENROSE CONFERENCE, JANUARY 18–24, 1999 plate boundaries? Is there a systematic and predictable progression of structures Subduction to Strike-slip that indicates that such a transition has occurred? What clues from these ancient Transitions on Plate Penrose events can be used to better understand active boundaries? (5) What are the seismic Boundaries CONFERENCE and tsunami hazards associated with sub- A Geological Society of America Penrose Conference, duction to strike-slip transition areas? Can “Subduction to Strike-slip Transitions on Plate Boundaries,” answers to tectonically related questions 1–4 will be held January 18–24, 1999, in Puerto Plata, Domini- above be used to better understand and per- can Republic. This location is within the active subduction to strike-slip transition area haps reduce these hazards? of the North America–Caribbean plate-boundary zone, so the conference will include a The conference is limited to 65 partici- field trip along the primary strike-slip fault (Septentrional fault zone) within the plate- pants. We encourage interested graduate stu- boundary zone. Shoreline features record recent activity of the offshore subduction dents to apply; some partial student subsi- boundary that included a magnitude 8.1 earthquake in 1946. dies will be available. The registration fee, which covers lodging, meals, field trips, and all other conference costs except personal The meeting will assemble a multi- and Irian Jaya, New Zealand and the Mac- incidentals, is not known at this time. Partic- disciplinary group of the world’s leading quarie Ridge, Indonesia, Thailand, Pakistan, ipants will be responsible for transportation experts from the United States, the and the Alpine-Mediterranean area. Experts to and from the conference. Further infor- Caribbean, New Zealand, Latin America, on other transition areas or on non–site- mation on travel will be provided in the let- Europe, and other areas. The purpose is to specific modeling work are welcome as ter of invitation. foster discussion of new ideas and develop participants. Co-conveners are: Paul Mann, associations between ideas drawn from dif- Discussion topics by keynote speakers Institute for Geophysics, University of ferent disciplines in earth science. Talks and and participants will include the following: Texas at Austin, 4412 Spicewood Springs Rd., discussions will focus on a better characteri- (1) How is plate motion partitioned between Austin, TX 78759, [email protected], zation of the tectonic controls and deforma- outboard subduction systems and inboard (512) 471-0452, fax 512-471-8844; tional effects of subduction to strike-slip strike-slip systems, and how do these fea- Nancy Grindlay, Dept. of Earth Sciences, transition areas. Experts in geology, seismol- tures interact to produce the observed pat- University of North Carolina, 601 South ogy, paleoseismology, geodesy, modeling of terns of diffuse seismicity and active fault- College Road, Wilmington, NC 28403-3297, geological and geophysical data, and deep ing? Is there any evidence for linked seismic [email protected], (910) 962-3736, fax seismic imaging will discuss deformation at events in the two systems? (2) Why are 910-962-7077; James F. Dolan, Dept. of all levels in lithosphere and mantle of sub- strike-slip to subduction transition areas Earth Sciences, University of Southern duction to strike-slip transition areas. This characterized by deep trenches that are the California, Los Angeles, CA 90089-0740, information will provide insights into the sites of some of the world’s largest gravity [email protected], (213) 740-8599, fax seismogenic mechanisms for the large and minima? (3) How does the behavior of sub- 213-740-0011. commonly destructive earthquakes that ducted slabs in subduction to strike-slip tran- Application deadline is August 1, affect these areas. sition areas affect upper crustal deformation 1998. Invitations will be mailed to par- Pariticpants will focus on the manifesta- in the transition region? What is the role of ticipants by September 1, 1998. Potential tion of both tectonic styles in tectonically slab rupture at depth, interaction of two participants should send a letter of applica- active areas including the Dominican opposed slabs at depth, extension of sub- tion to Paul Mann (address above), includ- Republic, Trinidad and eastern Venezuela, ducted slabs, and completely detached slabs ing a brief statement of interests, the rele- Panama and Costa Rica, the Scotia Sea, like the ones present in the mantle beneath vance of the applicant’s recent work to the northern California, eastern Alaska, the the Dominican Republic? (4) What is the themes of the conference, and a proposed western Aleutian arc and Kamchatka, Japan, sedimentary and structural record of subduc- title of the presentation (oral or poster; Taiwan, the Marianas trench, New Guinea tion to strike-slip transition along ancient poster preferred). ■

PENROSE CONFERENCE, MARCH 25–31, 1999 and (5) the interaction between back-arc spreading and subduction as revealed by Mid-Cretaceous to Recent Plate-Boundary seismic tomography. To discuss the implication of these Processes in the Southwest Pacific results and related studies on the tectonic evolution of the region, as well as future research directions, a Geological Society of The southwest Pacific region provides nental rifting to sea-floor spreading; (2) America Penrose Conference on “Mid-Creta- a natural laboratory for the study of plate recent geophysical studies that outline the ceous to Recent Plate-Boundary Processes boundary processes, and many different crustal and upper mantle structure of the in the Southwest Pacific” will be held concepts in relation to plate tectonics and central South Island of New Zealand—an March 25–31, 1999, at the Wilderness Lodge orogeny have originated as the result of ideal area for studying mountain-building near Arthur’s Pass, South Island, New studies there. Yet in many respects the evolu- processes at a transpressional plate bound- Zealand. That location provides easy access tion of the southwest Pacific has remained a ary; (3) recent work in the Ross Sea, in the to the active Australian-Pacific transpres- source of enigma and controversy. In the South Tasman Sea, and along the West sional plate boundary, where we will exam- past decade there have been many advances Antarctic margin that permits more accurate ine, during two field trips, the effects of in our understanding of plate boundary pro- reconstructions of Australia-Pacific plate mountain building and active deformation cesses in the area including (1) discovery of motion since late Eocene time; (4) the dis- processes. active metamorphic core complexes in the covery of active metallogenic systems that Woodlark Basin, as the result of lithospheric define important links between the active extension during the transition from conti- tectonic environments and ore deposition; Penrose Conference continued on p. 17

16 GSA TODAY, May 1998 STUDENT NEWS AND VIEWS If you happen to have made it to the safety of a lifeboat, there’s no sense in just Brian Exton, University of Texas at Austin drifting aimlessly in the dark. Getting What You Came For: The Smart Student’s Guide to Student News and Views provides GSA membership with commentary on matters relating to Earning a Master’s or a Ph.D., by Robert L. undergraduate and graduate students in the geosciences. The Correspondent for Student News Peters (Noonday Press, $12), is a compre- and Views welcomes comments and suggestions, sent to [email protected]. hensive guide not just to entering and sur- viving graduate school, but to excelling in it. Every aspect of the process, including To Seniors: Titanic Advice on the more mundane tasks such as selecting your thesis committee, are described in Grad School and Life great detail. Although the book is written for a more general audience, Peters’s Ph.D. was in fish behavior (he was adrift for a So you are about to graduate! Let me masses, or taking your chances in a while, too), so his examples are very rele- be one of the first to congratulate you and dinghy. Not much of a choice, eh? But vant. Take my word, reading this book can wish you the best success in whatever you there is help out there if you know where save you months of floundering through do next. If my guess is correct, you are to look. Along floats a book. Then a sec- departmental politics. probably headed in one of two direc- ond, and a third. No, these are not geol- For those of you beginning to send tions—back to school for an advanced ogy texts. These books are survival guides out an SOS (or CV), To Boldly Go: A Practi- degree, or head-first into the sea of from the first-class graduate student cal Career Guide for Scientists, by Peter S. humanity. Unfortunately, the cap and library on the promenade deck! O miracle Fiske, provides excellent suggestions on gown you are wearing weigh about as of miracles! how best to compose your message. This much as the Titanic, so you’re easily being For most of you, your small fortunes book is published by the American Geo- pulled under. Your diploma, on the other went down with the ship, but the first physical Union, and as such is geared par- hand, keeps you safely afloat. Hey, that book can help you resuscitate your ticularly to geoscientists. There is a com- piece of paper is worth something after all! finances. The Guerilla Guide to Mastering panion Web site (http://www.agu.org/ Thanks to the last four years of training, Student Loan Debt, by Anne Stockwell careerguide) with ordering information. your chances of survival look good. (HarperCollins, $14) is an indispensable My undergraduate advisor sent a copy to Before long, however, the water gets guide to the ins and outs of financing me recently, knowing that in a few years I a bit chilly. Many of you realize that for a your education and, once completed, will begin a systematic search for employ- career in geology, indeed for most of the repaying your student loans. The author ment (you can’t avoid the whirlpool for- sciences, a graduate degree is standard- financed much of her own education, and ever, although some of us are trying des- issue survival gear. Graduate school, if we combines personal experience with expert perately). Networking, job searching, and continue the analogy, is a lifeboat with advice from attorneys, collection agencies, current resources on the Internet are dis- room for only a few, rowing away at light legislators, loan officers, and others. cussed, but the most helpful aspect of this speed. Those of you who sacrifice your Unlike the hard-line positions you may guide is the half dozen case studies that worldly possessions to get on board know get from your school or lender, this book provide sample strategies for different that you’ll spend a good portion of your recognizes the fact that educational opportunities. life working to get it all back. As you strug- finance is big business in America ($100 The three books that were saved for gle into the boat and collapse in triumph, billion in student loans since 1990), and you today are priceless gems of wisdom. the rest of your classmates disappear into maintains that as a consumer of this prod- You should make a heroic effort to read at the roiling cauldron of life. Safe at last. uct, you have certain rights in addition least one of them, depending on the situa- But when you look around, many of the to your obligations. The title of the book tion in which you find yourself now. Fol- lucky souls in your boat are near exhaus- itself should give you some hint of the low their examples, and your chances of tion, and in some cases even attempting captivating style in which it was written. rescue, or in other words employment, will to jump overboard! Suddenly you’re not You may also want to visit the author’s increase exponentially. Good luck, and so sure of your decision any more. home page (http://home.earthlink.net/ bon voyage! ■ By now you should recognize yourself ~joegoode), which has links to a variety as someone floating along with the of related resources.

Penrose Conference continued from p. 16 Participation in the conference is lim- the meeting, and the subject of any pro- ited to 60 people, and those attending will posed presentation. Co-conveners are be selected to include a broad representation Suzanne Baldwin, Dept. of Geosciences, The main themes of the conference are: of disciplines. We encourage graduate stu- University of Arizona, UA P.O. Box plate reconstructions in the southwest dents whose thesis research is relevant to the 210077, Tucson, AZ 85721, (520) 621-9688, Pacific: the record from marine magnetic conference to apply; limited conference fax 520-621-2672, [email protected]; anomalies; subduction-related mantle flow funds will be available to support some grad- Gordon Lister, Australian Crustal in the southwest Pacific: insights from seis- uate students. The registration fee, which Research Centre, Dept. of Earth Sciences, mic tomography; magmatic processes: sub- will cover lodging, meals, field trips, and Monash University, Clayton, VIC 3168, duction initiation, polarity reversals, and the transportation during the meeting, is not Australia; 61-3-9905-5761, fax 61-3-9905-5062, interaction between subduction and backarc expected to exceed US$750. Participants will [email protected]. Potential spreading; mountain building and destruc- be responsible for transportation to and participants should send a letter of appli- tion along the Indo-Australian-Pacific plate from the conference venue. cation to Suzanne Baldwin. Formal invita- boundary; the transition from continental The application deadline is tions and additional information regard- extension to seafloor spreading; and metal- October 1, 1998. Letters of application ing travel arrangements will be mailed to logeny: ore deposits in active tectonic should include a brief statement of participants in early December 1998. ■ environments. research interests, the relevance of the applicant’s recent work to the themes of

GSA TODAY, May 1998 17 WASHINGTON REPORT Federation, and the United States. Most Asian countries chose not to participate. Bruce F. Molnia, [email protected] U.S. twelfth graders outperformed stu- dents from only two of the 21 participat- Washington Report provides the GSA membership with a window on the activities ing countries in math and science, Cyprus of the federal agencies, Congress and the legislative process, and international interactions and South . Otherwise, U.S. stu- that could impact the geoscience community. These reports present summaries of agency dents’ science scores were not significantly and interagency programs, track legislation, and present insights into Washington, D.C., different from those of students from geopolitics as they pertain to the geosciences. seven other countries, including Italy, Ger- many, France, and the Russian Federation. U.S. math scores were similar to those of four other countries, including Italy and The TIMSS Is Now To Begin To Improve the Russian Federation. TIMSS also examined how advanced U.S. Math and Science Education U.S. twelfth-grade students taking math, those studying precalculus and calculus, “Earlier this month our country received a wake-up call. Our high school seniors and those in science studying physics, ranked near the bottom in math and science achievement when compared with their performed in relation to advanced stu- peers around the world.… This must be a call to action for all of us.” dents in other nations. On the advanced math assessment, U.S. students were out- —President Bill Clinton, March 16, 1998 performed by those in 11 countries, were similar to those in four countries, and did “How can we expect our students to test well in math and science internationally not outperform any participating coun- when we do not even ask them to take challenging courses and rigorous tests tries. On the physics assessment, U.S. stu- throughout their middle and high school careers?” dents were outperformed by those in 14 countries, were the same as those in one —Education Secretary William Riley country, and outperformed no one. In all three areas of advanced math and in all five content areas of physics, In mid-March, President Clinton TIMSS is described by DOE as being a fair U.S. advanced math and physics students’ convened leaders from education, govern- evaluation and far more comprehensive performance was among the lowest of the ment, business, and the scientific com- than any previous study. The TIMSS test- TIMSS nations. On the assessment of math munity to discuss an appropriate national ing procedure was regulated to ensure that general knowledge, the U.S. score was 461. response to recent findings that showed the participating students in each country Hungary, Germany, Slovenia, Austria, U.S. twelfth graders lagged well below the were representative of its population. Canada, Australia, New Zealand, France, international average in science and math. The study has several parts, including Norway, Iceland, Switzerland, Denmark, These findings come from the Third Inter- a curriculum analysis component, a study Sweden, and the Netherlands had signifi- national Math and Science Study (TIMSS), of the curriculum presented in textbooks, cantly higher average scores than the U.S. released in late February by the Depart- and curriculum guides from each of the scores. The highest score was 560 in the ment of Education’s (DOE) National Cen- 41 countries. This analysis was conducted Netherlands. On the assessment of science ter for Education Statistics (NCES). The by hundreds of individuals from around general knowledge, the U.S. average score study was sponsored by the International the world who collected detailed analytic was 480. Denmark, Slovenia, Austria, Association for the Evaluation of Educa- content data from over 1,600 mathematics Switzerland, Australia, New Zealand, tional Achievement, a Netherlands-based and science textbooks and official curricu- Canada, Norway, Iceland, Netherlands, organization of ministries of education lum guides. The curriculum analysis com- and Sweden had significantly higher and research institutions in its member ponent was designed to uncover interna- average scores than the United States. countries. Each country participating in tional trends in implementing present and The highest score was 559 in Sweden. TIMSS paid for its own national data col- future mathematics and science education. The U.S. students who took the Advanced lection. U.S. participation in TIMSS It was also designed to be linked to data Mathematics TIMSS had already taken was supported by more than $30 million on instructional practices and student or were currently enrolled in precalculus, from the NCES and the National Science achievement. calculus, or advanced-placement calculus. Foundation. With respect to the U.S. twelfth They represented 14% of young people The study included participants from graders, four different areas of perfor- their age. Those who took the physics all over the world. DOE asserts, “Never mance—mathematics general knowledge, assessment had previously taken or were before has an international comparative science general knowledge, physics, and currently enrolled in physics. They also survey of education been conducted on advanced mathematics—were tested. represented 14% of the U.S. youngsters such a scale.” Nine- and thirteen-year-olds, These U.S. students were compared to their age. The United States was one of students in their last year of secondary students at the end of their secondary three countries that did not have a signifi- school, teachers, and the administrators school education in the other countries. cant gender gap in math general knowl- of their schools were all included in the In 21 countries, students were tested for edge among twelfth graders. While there TIMSS evaluations. According to DOE, general knowledge in mathematics and was a gender gap in U.S. science general “TIMSS is the world’s largest, most com- science. In addition, in 16 countries, knowledge, as there was in every other prehensive, and most rigorous interna- advanced students were tested in physics TIMSS nation, the U.S. gender gap was tional education comparison ever.” The and advanced mathematics. one of the smallest. study began in 1995, when researchers Among the countries included in An example of the type of question started testing the mathematics and sci- the study were Australia, Austria, Canada, asked for the advanced physics assessment ence knowledge of more than half a mil- Cyprus, Denmark, France, Germany, Hun- is “A car moving at a constant speed with lion students in 41 countries. In the gary, Iceland, Italy, Japan, New Zealand, a siren sounding comes towards you and United States, students from the fourth, the Netherlands, Norway, South Africa, eighth, and twelfth grades were included. Slovenia, Switzerland, Sweden, the Russian Washington Report continued on p. 19

18 GSA TODAY, May 1998 BOOK REVIEWS

Plate Tectonics and Crustal Evolu- The fourth edition of Condie’s book duction zones, , and tion (fourth edition). By Kent C. Condie. reflects a 20-year commitment to the title, the hypothesis of delamination. Too many Butterworth Heinemann, Oxford, UK, 1997, and the energy and effort spent on it are important recent advances are omitted—for $49.95 (paperback). impressive. It has been extensively rewrit- example, the existence of volcanic and non- ten—more than 75% according to the Pref- volcanic passive margins, the critical taper he crucial part of any science is the ace—and the fourth edition looks and feels model of accretionary prisms, extensional telling of what is known and why it is T completely different from the third (1989) collapse of orogens, and the fact that many important, and we do this in three different edition. Amazingly, the present volume is ophiolites are produced in forearcs at the ways. First and foremost, we write peer- much shorter (7 chapters and 282 pages) time subduction begins. The less-than- reviewed journal articles. This is where new than the third edition (11 chapters and 476 exhaustive treatment of important topics knowledge is reported, but journal articles pages). A comprehensive table of contents may be the unavoidable result of broaden- are designed for specialists. Second, we write and well-designed index make it easy to ing and shortening the book. The strongest introductory geology texts, but because navigate the book. The list of more than chapter in the book is chapter 4, “The these present the vast panorama of geologic 700 references is very up-to-date; I flipped Earth’s mantle and core.” This is a valuable knowledge to audiences with scientific many times to the back to check an unfa- and balanced synopsis of how Earth’s sub- backgrounds that range from limited to miliar—and invariably recent—reference. lithospheric interior operates, including the negligible, only basic principles, a lot of There are few typographical errors, a good distribution of isotopic components in the nomenclature and pretty pictures, and a few indication of care. mantle, mantle mineralogy and the signifi- scientific highlights can be presented. It is The book has several disappointing cance of upper mantle seismic discontinu- the third way—the book that presents a aspects, however. Its purpose and intended ities, how the geomagnetic dynamo oper- broad and up-to-date overview of the earth audience are not identified in the Preface. ates, and how the core may have formed. sciences to the “geoliterate”—that links the The title is misleading—this is really not a An entire chapter (6), “The atmospheres, specialist’s understanding and the neo- book about plate tectonics. The first chapter oceans, climates, and life” is added to the phyte’s curiosity. These are the books that gives an overview of modern plate bound- fourth edition, and although it is under- fire student imaginations, provide new aries and associated crustal environments, standable that hard-rock geologists want to material for science educators, and help sci- but at a level that is about what would be connect with the global change commu- entists answer questions that lie beyond found in a good introductory geology text. nity, chapter 6 doesn’t add much to the their expertise. Such books are essential for There is a discussion of “cycloid plate book. This is particularly true because this the continued vigor of our science, but are motions” that confuses more than it illumi- chapter contains a mistake—the assertion under-rewarded from both scientific and nates, and it is unclear why the short sec- that metazoan life began at 1.7 Ga, not in commercial perspectives. We owe a debt of tion on “stress distribution within plates” the late Neoproterozoic as most of the scien- thanks to those hearty souls—such as Kent was included. The second part of the title— tific community now accepts. Chapter 6 Condie—who take on the task of writing Crustal Evolution—is covered more exten- reinforces the idea that the fourth edition of books like Plate Tectonics and Crustal Evolu- sively in chapters 2, 3, and part of 5, but still Plate Tectonics and Crustal Evolution perhaps tion. And our debt should be doubled for inadequately, because many of the most reasonably priced books such as this one. important topics in crustal evolution are covered too briefly. Such topics include sub- Book Reviews continued on p. 20

Washington Report continued from p. 18 were outperformed in science only by international ranking isn’t the only cause Korea. By eighth grade, U.S. students’ for alarm here. If we’re to continue to be then passes by. Describe how the fre- relative standing declined, to only slightly global competitors in the new knowledge quency of the sound you hear changes.” above the international average in science economy, we’ll need a steady and compe- Thirty-seven percent of the international and below the international average in tent pool of employees. Right now, the participants answered this question cor- mathematics. One explanation given for low performance of those in the pipeline rectly. Only 12% of advanced U.S. stu- the poor performance in eighth grade for those future jobs has troubling impli- dents were able to provide the correct mathematics is that while most students cations for our future.” answer. Education Secretary William Riley in grades four to eight in other nations Riley also noted that 28% of high- stated, “This is unacceptable, and it abso- are studying the beginning concepts of school math teachers and 18% of high- lutely confirms what the president and I algebra, geometry, and other topics, U.S. school science teachers neither majored have been saying, that academic standards students continue to be taught primarily nor minored in these subjects. He chal- must be raised dramatically across America. arithmetic. lenged states and communities to ensure The standards of many state assessments “We need to have higher expectations that students are taught by teachers who in math are far lower than national and for our students ..., even among college are prepared to teach advanced math and international standards of excellence; bound high school seniors, 51 percent science. In the physical sciences, where too many science and math teachers have not even taken four years of science. student performance lags the most, almost are teaching out-of-field; and far too few This research also shows that our high half of American students are taught by high school seniors have taken physics, school curriculum and instruction has teachers without a major or minor in trigonometry, calculus and advanced less rigor and depth than other nations that field. placement courses.” and less focus on building understanding Copies of the report are available The results of the fourth- and eighth- of major concepts,” Riley noted. So we from the National Library of Education, grade TIMSS assessments were released in shouldn’t be surprised that by the twelfth (202) 219-1692. The report also will be 1996 and 1997, respectively. They showed grade, our students have fallen even far- available from the U.S. Government that the achievement of U.S. fourth-grade ther behind their counterparts abroad. Printing Office. Additional information students is quite high, performing above “We need to raise our expectations of our can be found on the TIMSS home page, the international average in both mathe- students if we want to be internationally (http://nces.ed.gov/timss/index.html). ■ matics and science. U.S. fourth graders competitive. Our twelfth graders’ low

GSA TODAY, May 1998 19 GSAF UPDATE Digging Up the Past Valerie G. Brown, Director of Development, GSA Foundation Most memorable early geologic GSA’s Fund-Raising Program: experience: Being shot at by an unknown Continuing to Thrive (Part 2) assailant while visiting an abandoned open-pit mine in Connecticut in the com- Last month we described the generos- In response to the need, the Boettcher pany of John Rodgers, ity of corporate donors to GSA’s program Foundation pledged a major challenge Bob Gates, Jim activities. grant of $132,000. Boettcher’s commitment Clarke, John Lucke, This month we honor the founda- reflected not only its long-standing dedica- and Bob Sneider. tions whose gifts are supporting GSA’s tion to furthering education in Colorado education and outreach initiatives. To but also the roots of its founding fortune in —John J. Prucha date, foundations have contributed Colorado’s mining enterprises. The grant $539,165 of the revenue received during required that an equivalent amount be the Second Century campaign. raised from other sources. GSA presented In this category, as with corporations, the challenge to El Pomar Foundation, a foundations whose generosity to GSA is we have two superstars—the Boettcher creation of the Penrose family. In 1934, the equally meaningful and equally worthy of Foundation, and El Pomar Founda- bequest of R. A. F. Penrose, Jr. ensured GSA’s our gratitude. So join us in thanking one tion—that together have given nearly welfare in a new phase of organization that wishes to remain anonymous and: half of the total received from founda- growth. In 1994, the present custodians of ARCO Foundation, Inc. tions. In fact, these outstanding gifts were the Penrose heritage agreed to meet the Bullitt Foundation literally paired with each other. Boettcher challenge, thereby securing GSA’s Frank A. Campini Foundation Flashback to 1994: The new addition next phase of growth and influence. Ecological Society of America to the headquarters building had just been These two gifts have funded acquisi- Foundation completed, and GSA had approved the tion of sophisticated electronic equipment Gates Foundation launch of several innovative technological that has noticeably improved GSA’s com- Howard and Jean Lipman Foundation education programs under the SAGE munications and publications capabilities Ruth and Vernon Taylor Foundation (Scientific Awareness through Geoscience and permitted implementation of SAGE Education) heading. The common ele- programs now applauded for their success- Although it is each foundation’s ment in these undertakings was the need ful contributions to science education. responsibility to give, it is each founda- for significant upgrades and additions to Accounting for the remaining half of tion’s election to give to GSA. We are truly the Society’s electronic capabilities. receipts in this category are several other grateful! ■

Book Reviews continued from p. 19 deposits. Most of the 23 contributing graphic work recently completed in parts of authors are internationally recognized the Sydney and Tasmania basins. tries to cover too much and consequently experts in their respective fields; hence, the A major omission of the volume, to lacks focus. treatments are up-to-date with the litera- which one author admits, is the lack of In summary, the book’s synopses of ture, and the reader can depend upon a rea- Antarctic Cenozoic glacial record and detail important geologic themes and the refer- sonably accurate representation of the on Quaternary events in the Southern ence list will be valued by advanced gradu- essential debates in each discipline. Hemisphere. Most of the Antarctic record ate students, professors, and other scientists, Clearly, in bringing these authors’ con- lies on the continental margins and speaks but the text must be refocused before it can tributions together, Martini is attempting directly as to what is likely to be preserved become optimally suited for a course in to provide a comparison of the environ- in ancient sequences (especially the late plate tectonics and crustal evolution mental changes brought about during and Precambrian -associated intervals, well intended for advanced undergraduate and following glacial episodes in the Phanero- presented by Young), and how. beginning graduate students and among zoic. With this goal in mind, I was satisfied The deep-marine record of Quaternary earth science educators. with some chapters and disappointed with events is well presented in the chapter by others. The problem in some chapters is Andrews, and terrestrial correlatives are Robert J. Stern that the authors present the chronostrati- evenly treated by Clarke, Baker, and University of Texas at Dallas graphic resolution typically associated with Lundqvist. The late Paleozoic chapters Richardson, TX 75083-0688 that time period and fail to address the fact focus upon intracratonic basins, which lack that Quaternary environmental changes a record comparable to that of the late Qua- Late Glacial and Postglacial Envi- were large but often associated with subtle ternary deep sea, where the majority of our ronmental Changes. Edited by I. Peter changes in the stratigraphic record (for paleoclimate record is archived. Thus, there Martini. Oxford University Press, New York, instance, isotopic stages and Heinrich lay- is a natural disjunct, due to preservation, 1997, 343 p. $65. ers in deep-sea sediments). Only a few of when one attempts to compare the two the authors presented views on ancient major Phanerozoic ice ages. The notable his multi-authored volume contains 19 glaciations that kept pace with Quaternary- exceptions to this are the fine chapters on chapters organized into five parts that T style events, notably the reliable work of Quaternary peat vs. Paleozoic coal deposits. center around three major ice ages: the Visser and Lopez-Gammundi on the Karoo It is this type of comparison that really Quaternary, late Paleozoic, and late Precam- and Parana basins, respectively. The repre- begins to shed light on the vagaries of Per- brian. The fifth part attempts to compare sentation of the Australian record was a dis- mian and Quaternary climate oscillations. the Quaternary and late Paleozoic events in appointment; it did not even reference terms of weathering and associated organic some of the excellent glacial marine strati- Book Reviews continued on p. 21

20 GSA TODAY, May 1998 Donors to the Foundation, February 1998

Antoinette Lierman Pooled Income Fund Ann G. Metzger J. Cotter Tharin Women in Science Medlin Scholarship John Montagne◆ Jack B. Mills Dean G. Wilder Holly L. O. Huyck Award William M. Schill Lauren A. Wright Robin L. Smith* Rip Rapp ◆ Freeport-McMoRan, Inc. Christopher Anne Suczek Frederick P. Young, Jr. Archaeological John E. Szatai Cordilleran Section Geology Award Endowment Fund George R. Rapp, Jr.* Christopher Anne Suczek◆ Research Grants Charles Lum Drake William D. Carlson GSA Foundation International Grant Howard W. Day 3300 Penrose Place J. Lamar Worzel* Michael J. Retelle P.O. Box 9140 Kurt Servos Shirley Dreiss Victor Vacquier Boulder, CO 80301 Memorial (303) 447-2020 Bruce A. Handel SAGE [email protected] Thomas J. Vaughn Dwornik Planetary Geoscience Award Shoemaker Fund Enclosed is my contribution in the amount of $______. Charles L. Gardner Robin Brett* Institute for Unrestricted Please add my name to the Century Plus Roster (gifts of $150 or Environmental Sofia M. Bobiak more). Education C. Ervin Brown Please credit my gift to the ______Fund. Independence Mining H. Roberta Dixon* ◆ Company, Inc. * Edward M. Dullaghan PLEASE PRINT Occidental Oil & Gas José L. Escriba M. Corporation◆* Owen D. Evans Name ______Alan D. Howard J. Hoover Mackin Arthur L. Lerner-Lam* Address ______Award Sonjia M. Leyva Joseph A. Mason John N. Louie City/State/ZIP ______Jack B. Mills Phone ______* Century Plus Roster (gifts of $150 or more). ◆ Second Century Fund.

Book Reviews continued from p. 20 ments, until recently scant attention has Australia and New Zealand, and the second been paid to this facies. This compendium and third emphasize Tertiary and Meso- of papers is an attempt to rectify the zoic-Paleozoic environments, respectively. As someone who teaches a nontradi- situation. Papers in the latter two sections deal with tional glacial geology course that treats Cool-Water Carbonates is a collected the sedimentology, geochemistry, and ancient and Quaternary events as well as series of papers dealing with carbonate sed- paleobiology of interpreted cool-water car- the marine record, I find that the book is a iments and rocks deposited on shelves and bonates mainly of Tertiary, Permian, Mis- useful volume of supplementary reading. offshore banks in waters colder than 20 °C. sissippian, and Late Ordovician age. These Others may find it somewhat less useful for The contributions come mainly from a periods of time seem to have recurring typical undergraduate courses, although it workshop, organized by Clarke and spon- examples of cool-water carbonates. The is a very good graduate and research refer- sored by the Australian Sedimentology question, of course, is why? ence and should be in all geology libraries. Research Group of the Geological Society Of the exciting new developments in Eugene W. Domack of Australia, held in Geelong, Victoria, in carbonate sedimentology and geochem- Hamilton College January 1995. This SEPM Special Publica- istry in recent years, not the least is the Clinton, NY 13323 tion joins a long line of outstanding vol- recognition that significant deposits of umes in this series in the field of sedimen- sedimentary carbonates can be formed in tary geology. The volume includes 24 seawaters other than tropical. Cool-Water Cool-Water Carbonates. Edited by Noel P. papers that deal with a range of topics and Carbonates is an excellent summary of the James and Jonathan A. D. Clarke. SEPM (Soci- case studies involving the deposition and present status of understanding and cur- ety for Sedimentary Geology Special Publication diagenesis of modern cool-water carbon- rent research involving this facies. It is a 56), Tulsa, Oklahoma, 1997, 440 p., $111. ates and those from the rock record inter- volume for research scientists and students here is a vast literature on the sedimen- preted as being deposited in cool-water alike interested in sedimentary carbonates T tary geology of carbonate sediments environments of banks, shelves, and plat- in general and in particular in these facies, and rocks deposited in tropical settings. forms. After a very readable and informa- which may represent a far larger propor- Although there are important carbonate tive paper by Noel James summarizing the tion of the sedimentary carbonate mass accumulations on the modern seafloor sedimentary geology of the cool-water than heretofore recognized. formed in seawater colder than 20 °C, depositional realm, the book is divided Fred T. Mackenzie and there are many carbonate rocks in t into three sections. The first section deals University of Hawaii he geologic record that bear evidence of with the modern depositional milieu, with Honolulu, HI 968220 ■ being deposited in cool-water environ- emphasis on the “down-under” settings of

GSA TODAY, May 1998 21 NOMINATION FOR GSA COMMITTEES FOR 1999

Name of candidate ______(One form per candidate, please. Additional forms may be copied.) Address ______(Please print) ______

Phone () ______

COMMITTEE(S) BEING VOLUNTEERED or NOMINATED FOR (please check): Committee(s): Comment on special qualifications:

GSA Fellow Section affiliation: GSA Member Division affiliation(s): Brief summary of education:

Brief summary of work experience (include scientific discipline, principal employer—e.g., mining industry, academic, USGS, etc.):

If you are VOLUNTEERING to serve GSA, please give the names If you are NOMINATING SOMEONE other than yourself to of 2 references (please print): serve GSA, please give your name, address, and phone number (please print): Name:______Name: ______Phone: ( ) ______Address: ______Name: ______Address: ______Phone: ( ) ______Phone: ( ) ______

DEADLINE: Please return this form to GSA Headquarters, Attn: Executive Director, P.O. Box 9140, Boulder, CO 80301-9140, by Friday, July 10, 1998. Form must be complete to be considered.

22 GSA TODAY, May 1998 Call For GSA Committee Service—1999 The GSA Committee on Committees Volunteering or Making a Committee on Committees wants your help. The committee is look- Recommendation The 1998 committee consists of the ing for potential candidates to serve on All nominations received at head- following people: Chair Marcus E. committees of the Society or as GSA rep- quarters by Friday, July 10, 1998, Milling, American Geological Institute, resentatives to other organizations. You on the official one-page form will be for- 4220 King St., Alexandria, VA 22302- can help by volunteering yourself or sug- warded to the Committee on Commit- 1502, (703) 379-2480; Laurie Brown, gesting the names of others you think tees. Council requires that the form be com- Department of Geosciences, University of should be considered for any of the plete. Information requested on the form Massachusetts, 233 Morrill Science Cen- openings and submitting your nomina- will assist the committee members with ter, Amherst, MA 01803, (413) 545-0245; tion on the form on page 22. Younger their recommendations for the 1999 Karl W. Flessa, Geoscience Department, members are especially encouraged to committee vacancies. Please use one form University of Arizona, 1840 E. 4th St., become involved in Society activities. per candidate (additional forms may be Tucson, AZ 85721, (520) 621-7336; Don Listed are the number of vacancies copied). The committee will present at O. Hermes, Department of Geology, Uni- along with a brief summary of what each least two nominations for each open versity of Rhode Island, 315 Green Hall, 8 committee does and what qualifications position to the Council at its October 27, Ranger Road, Suite 2, Kingston, RI 02881, are desirable. If you volunteer or make 1998, meeting in Toronto, Ontario. (401) 874-2192; Eric W. Mountjoy, recommendations, please give serious Appointees will then be contacted and Department of Earth and Planetary Sci- consideration to the special qualifications asked to serve, thus completing the pro- ence, McGill University at Montreal, for serving on cess of bringing new expertise into Soci- Province of Quebec, H3A 2A7, Canada, a particular committee. Please be sure that ety affairs. (524) 398-4894; Frederick L. Schwab, your candidates are Members or Fellows of Department of Geology, Washington & the Society and that they meet fully the Lee University, Lexington, VA 24450, requested qualifications. (540) 463-8870.

Committee Vacancies Annual Program (5 vacancies) Committee members work with other interested scientific Develops a plan for increasing the quality of the annual meeting organizations and science teachers’ groups to develop precollege in terms of service, education, and outreach. Evaluates the tech- earth-science education objectives and initiatives. The committee nical and scientific programs of the annual meeting. also promotes the importance of earth-science education to the Committee members should have previous program experi- general public. ence or experience at organizing an annual meeting, or be actively involved in applying geology knowledge to benefit soci- Geology and Public Policy (3 vacancies) ety and awareness of critical issues. Translates knowledge of the earth sciences into forms most useful for public discussion and decision making. Continuing Education (2 vacancies) Committee members should have experience in public-pol- Directs, advises, and monitors the Society’s continuing education icy issues involving the science of geology. They should also be program, reviews and approves proposals, recommends and able to develop, disseminate, and translate information from the implements guideline changes, and monitors the scientific qual- geologic sciences into useful forms for the general public and for ity of courses offered. the Society membership; they should be familiar with appropri- Committee members should be familiar with continuing ate techniques for the dissemination of information. education programs or have adult education teaching experience. Honorary Fellows (2 vacancies) Day Medal (3 vacancies) Selects candidates for Honorary Fellows, usually non–North Selects candidates for the Arthur L. Day Medal. Americans. Committee members should have knowledge of those who Committee members should have knowledge of geologists have made “distinct contributions to geologic knowledge throughout the world who have distinguished themselves through the application of physics and chemistry to the solution through their contributions to the science. of geologic problems.” Membership (1 vacancy) Education (3 vacancies—2 at large; Evaluates membership benefits and develops recommendations 1 middle school teacher) that address the changing needs of the membership and attracts Stimulates interest in the importance and acquisition of basic new members. knowledge in the earth sciences at all levels of education. Committee members must be able to attend one meeting a year. Previous experience in benefit, recruitment, and retention programs is desired. Minorities and Women (3 vacancies) The GSA Council acknowledges the many member-volunteers who, over the years, have stimulated growth and change through their in the Geosciences involvement in the affairs of the Society. Stimulates recruitment and promotes positive career develop- ment of minorities and women in the geoscience professions. Each year GSA asks for volunteers to serve on committees, and Committee members should be familiar with minority and many highly qualified candidates express their willingness to serve. female education and employment issues and have expertise and Not everyone can be appointed to the limited number of vacancies; leadership experience in such areas as human resources and edu- however, members are reminded that there are also opportunities cation. Membership shall include representation of minorities to serve in the activities and initiatives of the sections and divisions. and women and representatives from government, industry, and Annually, the Council asks sections and divisions to convey the academia. names of potential candidates for committee service to the Com- mittee on Committees. Committee Service continued on p. 24

GSA TODAY, May 1998 23 1998–1999 GSA ON Section Officers and Past Chairs THE WEB

Visit the GSA Web Site at CORDILLERAN SECTION SOUTH-CENTRAL SECTION http://www.geosociety.org. From Gregory A. Davis ...... Chair M. Charles Gilbert ...... Chair our home page you can link to many infor- Margaret E. Rusmore ...... Vice-Chair Calvin Barnes ...... Vice-Chair mation resources. Here are some highlights: Bruce A. Blackerby ...... Secretary Rena M. Bonem ...... Secretary-Treasurer As of April 10, the electronic abstract Alison B. Till ...... Past Chair Elizabeth Y. Anthony ...... Past Chair submittal form is LIVE, and ready for your submittals. Go to the GSA Home ROCKY MOUNTAIN SECTION NORTHEASTERN SECTION Page, and under the “Annual Meetings & Scott S. Hughes ...... Chair Allan Ludman ...... Chair Penrose Conferences” click on the link Glenn D. Thackray ...... Vice-Chair Robert D. Jacobi ...... Vice-Chair “Submit an abstract for the 1998 Annual Kenneth E. Kolm ...... Secretary Kenneth N. Weaver .... Secretary-Treasurer Meeting in Toronto.” You may choose to Larry T. Middleton ...... Past Chair Jon C. Boothroyd ...... Past Chair review instructions, or if you are already Ronald C. Blakey ...... Past Vice-Chair knowledgable about our system, you may wish to jump right to the abstract form. NORTH-CENTRAL SECTION SOUTHEASTERN SECTION When your abstract is complete, you will Dennis Kolata ...... Chair R. Heather MacDonald ...... Chair be directed to our secured credit card Ardith K. Hansel ...... Vice-Chair Samuel E. Swanson ...... Vice-Chair page. Again this year, there is a nonre- Robert F. Diffendal, Jr...... Secretary Harold H. Stowell ...... Secretary-Treasurer fundable fee of $15 for each abstract sub- William I. Ausich ...... Past Chair Ernest A. Mancini ...... Past Chair mittal. If you need paper abstract forms, Walter C. Sweet ...... Past Vice-Chair Larry D. Woodfork ...... Past Vice-Chair please contact [email protected].

major maps, and 21 transects—nearly He also managed the receipt and Jim Clark Retires 16,000 pages in all; he was also responsi- processing of all abstracts for section and GSA Publications Production and ble for marketing eight additional vol- annual meetings, and the production of Marketing Manager James R. (Jim) Clark umes produced in Canada. the GSA Abstracts with Programs. He has retired after more than 18 years on Clark conceived the idea for the designed the familiar GSA abstract forms the headquarters staff of the Society. Dur- best-selling volume, The Art of Geology and was co-designer and co-creator of ing that time, he oversaw the produc- (Special Paper 225) as a GSA Centennial GSA’s Web-based electronic abstract- tion, manufacture, distribution, and mar- specialty book for nongeologists, and submittal system, now in its third year keting of 684 issues of GSA periodicals, coordinated its production. He instituted of use for annual meetings. about 88 issues of Abstracts with Programs, GSA Journals on Compact Disc, now a Clark moved GSA’s publications and 328 of GSA’s nonperiodicals: Mem- semi-annual release with nearly 600 sub- through many technological changes, oirs, Special Papers, Maps and Charts, scribers. He designed and initiated sev- into the current desk-top publishing. etc. eral Web-based systems including the He coordinated the computerization of In addition, he organized and man- GSA Bookstore on the Web and its atten- many publications functions, personally aged the marketing, production, manu- dant purchasing system; the GSA Data designing many GSA data sets and their facture, and distribution of the Decade of Repository on the Web, and the GSA supporting systems. North American Geology (DNAG) publi- Electronic Retrospective Index on both cations: 30 volumes, 157 plates, seven CD-ROM and the Web.

Committee Service continued from p. 23 research in pure geology, which marks a major advance in the science of geology.”

Nominations (2 vacancies; one to be a member Research Grants (0 vacancies) from Canada or Mexico) Evaluates research grant applications and selects grant recipients. Recommends to the Council nominees for the positions of GSA Committee members must be able to attend the spring meet- officers and councilors. ing and should have experience in directing research projects and Committee members should be familiar with a broad range in evaluating research grant applications. of well-known and highly respected geological scientists. Young Scientist Award (Donath Medal) (2 vacancies) Penrose Conferences (1 vacancy) Selects candidates for the Donath Medal. Reviews and approves Penrose Conference proposals, recom- Committee to have members covering a broad range of disci- mends and implements guidelines for the success of the plines, i.e., geophysics, economic geology, stratigraphy. Commit- conferences. tee members should have knowledge of young scientists with Committee members must either be past conveners or have “outstanding achievement(s) in contributing to geologic knowl- attended two or more Penrose Conferences. edge through original research which marks a major advance in the earth sciences.” Penrose Medal (2 vacancies) Selects candidates for the Penrose Medal. GSA Representative to the North American Commission Committee members should be familiar with outstanding on Stratigraphic Nomenclature (1 vacancy) achievements in the geological community that are worthy of Must be familiar with and have expertise in stratigraphic consideration for the honor. Emphasis is placed on “eminent nomenclature. ■

24 GSA TODAY, May 1998 VOLUME 26 May BULLETIN and NO. 5 P. 385Ð480 GEOLOGY Contents MAY 1998 387 Recognition of interfluve sequence boundaries: Integrating paleo- pedology and sequence stratigraphy Paul J. McCarthy, A. Guy Plint 391 Remnants of Paleozoic cover on the Archean Canadian Shield: The Geological Society of America Limestone xenoliths from kimberlite in the central Slave craton Harrison O. Cookenboo, Michael J. Orchard, David K. Daoud 395 Control on sediment and organic carbon delivery to the Arctic Ocean revealed with space-borne synthetic aperture radar: Ob’ River, Siberia Volume 110, Number 5, May 1998 Laurence C. Smith, Douglas E. Alsdorf 399 Changes in the hydrothermal system at Loihi Seamount after the CONTENTS formation of Pele’s pit in 1996 Alicé S. Davis, David A. Clague 537Ð552 Collapse, infilling, and postimpact deformation at the Mj¿lnir 403 U-Pb dates of paleosols: Constraints on late Paleozoic cycle durations impact structure, Barents Sea and boundary ages Filippos Tsikalas, Steinar Thor Gudlaugsson, and Jan Inge Faleide E. T. Rasbury, G. N. Hanson, W. J. Meyers, W. E. Holt, R. H. Goldstein, A. H. Saller 407 Helium isotopes in early Tertiary basalts, northeast Greenland: Petrologically diverse basalts from a fossil oceanic forearc in Cali- Evidence for 58 Ma plume activity in the North Atlantic–Iceland 553Ð571 volcanic province fornia: The Llanada and Black Mountain remnants of the Coast Bernard Marty, Brian G. J. Upton, Rob M. Ellam Range ophiolite 411 Carbonate versus silicate weathering in the Raikhot watershed within Mario Giaramita, Glenn J. MacPherson, and Stephen Paul Phipps the High Himalayan Crystalline Series Joel D. Blum, Carey A. Gazis, Andrew D. Jacobson, C. Page Chamberlain 572Ð587 Stonewall anticline: An active fold on the Oregon continental shelf 415 Evidence for abrupt latest Permian mass extinction of foraminifera: Robert S. Yeats, LaVerne D. Kulm, Chris Goldfinger, and Lisa C. Results of tests for the Signor-Lipps effect McNeill Michael R. Rampino, Andre C. Adler 419 Cryptic crustal events elucidated through zone imaging and ion 588Ð614 Tectonic implications of rapid cooling of lower plate rocks from the microprobe studies of zircon, southern Appalachian Blue Ridge, Buckskin-Rawhide metamorphic core complex, west-central Ari- North Carolina–Georgia zona Calvin F. Miller, Robert D. Hatcher, Jr., T. Mark Harrison, Christopher D. Coath, Robert J. Scott, David A. Foster, and Gordon S. Lister Elizabeth B. Gorisch 423 Role of the continental margin in the global carbon balance during 615Ð629 Paleozoic and Mesozoic high-pressure metamorphism at the margin the past three centuries of ancestral North America in central Yukon Fred T. Mackenzie, Abraham Lerman, Leah May B. Ver 40 39 Philippe Erdmer, Edward D. Ghent, Douglas A. Archibald, and 427 Inherited argon in a Pleistocene andesite lava: Ar/ Ar incremental- Mavis Z. Stout heating and laser-fusion analyses of plagioclase B. S. Singer, J. R. Wijbrans, S. T. Nelson, M. S. Pringle, T. C. Feeley, M. A. Dungan Volcaniclastic aggradation in a semiarid environment, northwestern 431 Metasomatism of the shallow mantle beneath Yemen by the Afar 630Ð643 plume—Implications for mantle plumes, flood volcanism, and Vulcano Island, Italy intraplate volcanism Greg A. Valentine, Danilo M. Palladino, Emanuela Agosta, Jacopo Joel Baker, Gilles Chazot, Martin Menzies, Matthew Thirlwall Taddeucci, and Raffaello Trigila 435 Necessary conditions for a meandering-river avulsion Rudy Slingerland, Norman D. Smith 644Ð663 Distal Ancestral Rocky Mountains tectonism: Evolution of the Penn- 439 Boron-rich mud volcanoes of the Black Sea region: Modern analogues sylvanian-Permian OquirrhÐWood River basin, southern Idaho to ancient sea-floor tourmalinites associated with Sullivan-type Jeffrey K. Geslin Pb-Zn deposits? John F. Slack, Robert J. W. Turner, Paul L. G. Ware 664Ð678 Paleobotanical evidence of Eocene and Oligocene paleoaltitudes in 443 Environmental change controls of lacustrine carbonate, Cayuga Lake, midlatitude western North America New York Jack A. Wolfe, Chris E. Forest, and Peter Molnar Henry T. Mullins 447 Dating of a regional hydrothermal system induced by the 1850 Ma 679Ð684 Mesozoic tectonics and metamorphism in the Pequop Mountains and Sudbury impact event Wood Hills region, northeast Nevada: Implications for the architec- D. E. Ames, D. H. Watkinson, R. R. Parrish ture and evolution of the Sevier orogen: 451 Stratigraphic hierarchy of organic carbon–rich siltstones in deep- Discussion: Jim Wise water facies, Brushy Canyon Formation (Guadalupian), Delaware Reply: Phyllis A. Camilleri and Kevin R. Chamberlain Basin, West Texas Bradley B. Sageman, Michael H. Gardner, John M. Armentrout, Adam E. Murphy Regional tilt of the Mount Stuart batholith, Washington, determined 455 Influence of magma supply and spreading rate on crustal magma 685Ð690 bodies and emplacement of the extrusive layer: Insights from the using aluminum-in-hornblende barometry: Implications for north- East Pacific Rise at lat 16°N ward translation of Baja British Columbia: Suzanne Carbotte, Carolyn Mutter, John Mutter, Gustavo Ponce-Correa Discussion: Scott R. Paterson and Robert B. Miller 459 Bryozoan carbonates through time and space Reply: Mark T. Brandon and Jay J. Ague Paul D. Taylor, Peter A. Allison

463 Annual cycle of magmatic CO2 in a tree-kill soil at Mammoth 691Ð694 Estuarine circulation in the Turonian Western Interior seaway of Mountain, California: Implications for soil acidification North America: Kenneth A. McGee, Terrence M. Gerlach Discussion: Paul W. Jewell 467 Effect of subducting sea-floor roughness on fore-arc kinematics, Reply: Rudy Slingerland, Lee R. Kump, Mike A. Arthur, Peter J. Pacific coast, Costa Rica Fawcett, Bradley B. Sageman, and Eric J. Barron D. M. Fisher, T. W. Gardner, J. S. Marshall, P. B. Sak, M. Protti 471 Late Holocene ~1500 yr climatic periodicities and their implications Ian D. Campbell, Celina Campbell, Michael J. Apps, Nathaniel W. Rutter, Andrew B. G. Bush Forum 474 Extensional collapse along the Sevier Desert reflection, northern Visit Sevier Desert basin, western United States Comment: Mark H. Anders, Nicholas Christie-Blick, Stewart Wills http:// Reply: James C. Coogan, Peter G. DeCelles 475 Dome-and-keel provinces formed during Paleoproterozoic orogenic collapse—Core complexes, diapirs, or neither?: Examples from the www. Quadrilátero Ferrífero and the Penokean orogen @ Comment: Daniel Holm, David Schneider, Daniel Lux Reply: Stephen Marshak, Douglas Tinkham, Fernando F. Alkmim, Hannes Brueckner, geosociety.org Theodore Bornhorst GSA 477 The need for mass balance and feedback in the geochemical carbon cycle Comment: Mike J. Bickle; Reply: Ken Caldeira, Robert A. Berner 479 Continuous record of reef growth over the past 14 k.y. on the mid- Shop the GSA Bookstore! Pacific island of Tahiti Comment: Paul Blanchon; Reply: Lucien F. Montaggioni, Edouard Bard

GSA TODAY, May 1998 25 Call for Applications and Nominations for GSA BULLETIN Editor

The term of one of the current editors of the GSA Bulletin will end EDITOR QUALITIES December 31, 1998, and a new editor will begin a four-year term 1. Broad background and active research at that time. Thus, GSA is soliciting applications and nominations in the geological sciences, with for the position of editor of the Bulletin. A phased transition should particular emphasis on regional geol- begin in the fall of 1998. ogy (including geomorphology, geophysics, This is not a salaried position, but GSA pays the expenses for secre- geochemistry). tarial assistance, mail, and telephone at the editors’ locations and 2. Good organizational skills. for travel to GSA headquarters. GSA headquarters staff conducts 3. Capability to coordinate working schedules copy-editing and production activities. with a co-editor. 4. Willingness to invest about one day per week EDITOR DUTIES on Bulletin-related activities. Working as a team, the two Bulletin editors: 5. Enthusiasm and imagination for promoting innovations 1. Strive to maintain the Bulletin as one of the premier and improvements in the Bulletin. journals in the geological sciences. 6. Broad knowledge of geological research activities of 2. Select and maintain an appropriate board of Associate scientists both nationally and internationally. Editors. 7. Effective communication skills. 3. Maintain expeditious manuscript flow. 8. Objectivity. 4. Make decisions regarding acceptability of manuscripts in 9. Scientific maturity. concert with recommendations of reviewers and Associate 10. Patience, courtesy, tact, and firmness in working with Editors. authors and Associate Editors. 5. Advise authors about necessary revisions. 6. Organize the content and select the cover illus- If you are interested in applying, submit a resume and a brief tration for each issue of the Bulletin. letter describing relevant qualifications, experience, and 7. Keep the Committee on Publications and the objectives. If you are nominating someone, include a letter GSA headquarters staff informed about the of nomination and the nominee’s written permission and flow of manuscripts and other Bulletin business. resume. Send nominations and applications to Donald M. 8. Respond promptly to inquiries from authors and Davidson, Jr., Executive Director, Geological Society of prospective authors. America, P.O. Box 9140, Boulder, Colorado 80301, by July 15, 1998.

1998 Committees and Representatives

Executive Committee Committee on the Arthur L. Day Medal Award Victor R. Baker—President and Chair; Gail M. Ashley—Vice-Presi- J. Leslie Smith—Chair, 1998; Richard G. Gordon, 1996–1998; dent; George A. Thompson—Past President; David E. Dunn— Robert Kerrich, 1996–1998; Kip V. Hodges, 1997–1999; Julie D. Treasurer; John E. Costa—Council Member-at-Large Morris, 1998–2000; E. Calvin Alexander, Jr., 1998–2000; Jon P. Davidson, 1998–2000 Annual Program Committee —Chair, 1996–1998; G. Randy Keller, 1995–1998; Committee on Education Orrin H. Pilkey, Jr., 1995–1998; John M. Bartley, 1996–1998; David W. Mogk—Chair, 1996–1998; Debbie M. Hill, 1996–1998; Jonathan G. Price, 1996–1998; Denis M. Shaw, 1997–1999; Kenneth L. Verosub, 1996–1998; R. Heather MacDonald, 1997– Ex officio: Sue S. Beggs—Meetings Director; Donald M. 1999; Madge Evans, 1997–1999; Maureen Allen, 1998–2000; Sec- Davidson, Jr.—Executive Director; John D. Humphrey tion representatives: Elizabeth Ambos (Cordilleran); Cathleen L. May (Rocky Mountain); Sherman P. Lundy (North-Central); Audit Committee Frances (Betsy) E. Julian (South-Central); Daniel P. Murray (North- Charles G. Groat—Chair, 1996–1998; Morris W. Leighton, eastern); John E. Callahan (Southeastern); Ex officio: Gail M. Ash- 1997–1999; Gail A. Mahood, 1997–1999; Melvin J. Hill, ley—Vice-President; Conferee: Edward E. Geary—Director of Edu- 1998–2000; Joaquin S. Ruiz, 1998–2000; Ex officio: David E. cational Programs Dunn—Treasurer Committee on External Awards Committee on the Budget Warren B. Hamilton—Chair; J. Leslie Smith; Division Represen- David E. Dunn—Chair and Treasurer; Samuel S. Adams, tatives: James R. Staub (Coal Geology); William C. Haneberg 1996–2000; Arden L. Albee, 1998–2002; Ex officio: Donald M. (Engineering Geology); George A. Thompson (Geophysics); Davidson, Jr.—Executive Director; Dennis G. Kyhos—Chief (vacant—Geoscience Education); William R. Brice (History Financial Officer of Geology); Leslie D. McFadden (Quaternary Geology and Geomorphology) Committee on Committees Marcus E. Milling—Chair; Laurie Brown; Karl W. Flessa; Don O. Committee on Geology and Public Policy Hermes; Eric W. Mountjoy; Frederick L. Schwab Monica E. Gowan—Chair, 1996–1998; Peter F. Folger—Chair Designee, 1997–1999; J. David Applegate, 1996–1998; Robert H. Committee on Continuing Education Rutford, 1996–1998; Lee C. Gerhard, 1997–1999; James M. Carolyn G. Olson—Chair, 1996–1998; Jean M. Bahr, 1996–1998; Robertson, 1997–1999; James E. Evans, 1998–2000; Virgil A. Odin D. Christensen, 1997–1999; Grant R. Woodwell, 1997–1999; Frizzell, Jr., 1998–2000; Sally J. Sutton, 1998–2000; Past Congres- Charles G. Groat, 1998–2000; David S. McCormick, 1998–2000 sional Science Fellows: Jill S. Schneiderman, 1996–1998; Peter F. Folger, 1997–1999; Tamara J. Nameroff, 1998–2000; Ex officio:

1998 Committees continued on p. 27

26 GSA TODAY, May 1998 1998 Committees continued from p. 26 Committee on the Young Scientist Award (Donath Medal) Thomas L. Holzer—Chair, 1996–1998; Brian P. Wernicke, 1996– (Section representatives): Robert H. Fakundiny (Northeastern); 1998; Randall R. Parrish, 1997–1999; Robert C. Thunell, 1997– Thomas J. Evans (North-Central); Jerome V. DeGraff (Cor- 1999; Judith L. Hannah, 1998–2000; W. Berry Lyons, 1998–2000 dilleran); Cathleen L. May (Rocky Mountain); John D. Kiefer (Southeastern); (vacant—South-Central); Conferee—ad hoc Ad Hoc Committee on Critical Issues Committee on Critical Issues: Allison R. (Pete) Palmer; Ex officio: Alison R. (Pete) Palmer—Chair; Mary Barber; Kenneth L. Conca; Paul K. Doss—Past Chair; Elizabeth S. Knapp—(Acting) IEE George W. Fisher; William S. Fyfe; R. Gordon Gastil; Carroll Ann Program Manager; Council/Committee Liaison: George A. Hodges; Susan W. Kieffer; Emlyn Koster; Richard B. Norgaard; Alli- Thompson—Past President son R. (Pete) Palmer; Daniel Sarewitz; Jill S. Schneiderman; A. Wes- ley Ward, Jr. Committee on Honorary Fellows Parke D. Snavely III—Chair, 1997–1999; Gerhard H. Eisbacher, Ad Hoc Committee on Ethics 1996–1998; Miriam Kastner, 1996–1998; Brian J. Skinner, David A. Stephenson—Chair; Donald M. Davidson, Jr.; 1997–1999; Michael A. Dungan, 1998–2000; Donald R. Lowe, Fletcher G. Driscoll; Richard I. Grauch; Thomas L. Holzer 1998–2000; Ex officio: Ian W. D. Dalziel—International Secretary Ad Hoc Committee on the GSA Strategic Plan Committee on Investments Victor R. Baker—GSA President; Gail M. Ashley; Sue S. Beggs; Carel Otte—Chair, 1996–1998; R. Thayer Tutt, Jr., 1996–1998; Joanne Bourgeois; Valerie G. Brown; Bruce Clark; Donald M. F. Michael Wahl., 1996–1998; John E. Costa, 1998–2000; Davidson, Jr.; George H. Davis; Edward E. Geary; Dennis Kyhos; Melvin J. Hill, 1998–2000; Ex officio: David E. Dunn—Treasurer; Eldridge M. Moores; Sharon M. Mosher; Daniel Sarewitz; David A. Brian J. Skinner—GSA Foundation designee Stephenson; George A. Thompson; Susan Ward Committee on Membership GSA Member of the American Geological Institute William D. Carlson—Chair, 1997–1999; Richard W. Ojakangas, (AGI) Member Society Council 1996–1998; George H. Davis, 1997–1999; Reinhard A. Wobus, George A. Thompson, 1996–1998 1997–1999; Bruce A. Bouley, 1998–2000; Kenneth L. Pierce, 1998–2000 GSA Member of the AGI Education Advisory Committee Committee on Minorities and Women Edward E. Geary—GSA Director of Educational Programs in the Geosciences Mary E. Dowse—Chair, 1998–2000; Kathleen E. Johnson, GSA Member of the AGI Government Affairs Program 1996–1998; Lauret E. Savoy, 1996–1998; Barbara L. Sherriff, Advisory Committee 1996–1998; Rosaly Lopes-Gautier, 1997–1999; Joseph C. Cepeda, Virgil A. Frizzell, Jr., 1998–2000 1998–2000; James B. Finley, 1998–2000; Lisa A. Rossbacher, GSA Representatives to the American Association 1998–2000; Conferees: Joanne Bourgeois—Council/Committee Liaison; Edward E. Geary—Director of Educational Programs for the Advancement of Science (AAAS) Section E—Geology and Geography: Maryellen Cameron, Committee on Nominations February 19, 1997–Feb 22, 2000; Section W—Atmospheric and Peter W. Lipman—Chair, 1997–1998; Darrell S. Cowan, 1997– Hydrospheric Sciences: John G. Weihaupt, July 1, 1988– 1998; G. Randy Keller, 1997–1998; John W. Hess, Jr., 1998–1999; February 22, 2000 Lisa M. Pratt, 1998–1999; Derald G. Smith, 1998–1999 GSA Representatives to the AAAS Consortium of Committee on Penrose Conferences Affiliates for International Programs (CAIP) J. Douglas Walker—Chair, 1996–1998; Joann M. Stock, 1997– Ian W. D. Dalziel—International Secretary; Donald M. 1999; Thomas W. Gardner, 1998–2000; Naomi M. Oreskes, Davidson, Jr.—GSA Staff Liaison 1998–2000; Fred M. Phillips, 1998–2000 GSA Representatives to the North American Committee on the Penrose Medal Award Commission on Stratigraphic Nomenclature (NACSN) Warren B. Hamilton—Chair, 1998; Steven M. Stanley, 1996–1998; W. Burleigh Harris, 1995–1998; Ernest A. Mancini, 1996–1999; Phillip C. England, 1997–1999; John E. Suppe, 1997–1999; David T. King, Jr., 1997–2000; Ardith K. Hansel—Representative Leonard F. Konikow, 1998–2000; Mary J. Kraus, 1998–2000 Elect, 1998–2001 (term begins during the NACSN 1998 fall meeting in Toronto) Committee on Publications Joanne Bourgeois—Chair, 1996–1998; B. Clark Burchfiel, GSA Representative to the Treatise Editorial 1997–1999; Allison R. (Pete) Palmer, 1998–2000; Kevin T. Biddle, Advisory and Technical Advisory Boards of the 1997–1999; Abhijit Basu, Editor, Books; John W. Geissman, Paleontological Institute Editor, Bulletin; Lee R. Kump, Editor, Geology; John M. Sharp, Jr., John Pojeta, Jr.—Chair, Treatise on Invertebrate Paleontology Co-Editor, Environmental and Engineering Geoscience; Conferee: Advisory Committee Donald M. Davidson, Jr.—Executive Director GSA Representatives to the Joint ASCE-GSA-AEG Committee on Research Grants Committee on Engineering Geology (American Society James N. Connelly—Chair, 1997–1999; Duncan M. FitzGerald, of Civil Engineers, Association of Engineering Geologists) 1997–1999; Paul M. Myrow, 1997–1999; Thomas L. Patton, Donald C. Helm, 1997–1999; Bruce R. Rogers, 1997–1999 1997–1999; Allen F. Glazner, 1998–2000; Brian G. Katz, 1998– 2000; Jim E. O’Connor, 1998–2000; NSF Conferee: Thomas O. Wright GSA Representative to the U.S. National Committee on Scientific Hydrology Treatise on Invertebrate Paleontology David A. Stephenson, 1990–; John M. Sharp, Jr. (alternate) Advisory Committee John Pojeta, Jr.—Chair, 1995–1998; William I. Ausich, GSA and AASG Selection Committee for the John C. 1997–1999; Richard Arnold Davis , 1997–2000; Donald M. Frye Memorial Award in Environmental Geology Davidson, Jr., Executive Director (Association of American State Geologists) Frank E. Kottlowski—Chair, AASG representative; Richard C. Berg (tentative), GSA representative, 1998–2000; Larry D. Fellows, AASG representative ■

GSA TODAY, May 1998 27 GSA MEETINGS 1998 October 26–29 Metro Toronto Convention Centre Sheraton Centre Toronto Hotel www.geosociety.org/meetings/98 Abstracts due: July 13

GENERAL CHAIRS Jeffrey J. Fawcett, University of Toronto Peter von Bitter, Royal Ontario Museum TECHNICAL PROGRAM CHAIRS TORONTO Denis M. Shaw, McMaster 1998 Annual Meeting University Andrew Miall, University of Toronto ASSEMBLY OF A CONTINENT IELD RIP HAIRS F T C Call for Papers and First Announcement in the April issue of GSA Today. Pierre Robin, Henry Halls Registration and Housing information will be in the June issue. University of Toronto Both technical program and field trip deadlines have passed. Travel to Toronto • Visit the GSA Toronto Web site for links to travel information: www/geosociety.org/meetings/98, then e-mail us if you have any questions: [email protected]. Federal and State Employees • Put in your request NOW for foreign travel. Be sure the GSA Annual Meeting in Toronto is on the “approved” travel list. U.S. Visa Holders • Get in touch with your consulate NOW. Citizens or permanent residents of other countries must have a valid passport and/or a valid visitors visa and should contact their local Canadian Embassy, Consulate, or High Commission Office for further qual- ification. Travel and Immigration Information • For native-born Americans and/or U.S. citizens, it’s really easy! Canadian Immigration only requires either a passport or a birth certificate, supported by photo I.D. • A permanent resident who is not a citizen is required to possess a 1551 or 1151 form (“Green Card”) by both U.S. and Cana- dian Immigration. This is also easy! See you in Toronto! Have Enough Abstracts Forms for the 1998 GSA Annual Meeting? GSA SECTION MEETING ☛ If not … request them NOW. 1998 ROCKY MOUNTAIN SECTION, May (303) 447-2020, ext. 161 • e-mail: [email protected]. 25–26, Northern Arizona University, Flagstaff, Arizona. Information: Larry Middleton, Dept of For electronic submission Information is available under Geology, Box 4099, Northern Arizona Univer- the Meetings heading on the GSA home page at http://www.geosociety.org. sity, Flagstaff, AZ 86011, (520) 523-2492, [email protected]. Remember Deadline for receipt at GSA is July 13.

28 GSA TODAY, May 1998 1999 CALL FOR CONTINUING EDUCATION COURSE PROPOSALS Denver, Colorado Due December 1, 1998 October 25–28 The GSA Committee on Continuing Education invites those interested in Colorado Convention Center proposing a GSA-sponsored or cosponsored course or workshop to contact GSA headquarters for proposal guidelines. Continuing Education courses may be conducted in conjunction with all GSA annual or section meetings. We are par- GENERAL CO-CHAIRS ticularly interested in receiving proposals for the 1999 Denver Annual Meeting Mary J. Kraus, David Budd, University or the 2000 Reno Annual Meeting. of Colorado Proposals must be received by December 1, 1998. Selection of courses for 1999 TECHNICAL PROGRAM CHAIRS will be made by February 1, 1999. For those planning ahead, we will also consider Craig Jones, G. Lang Farmer, University courses for 2000 at that time. of Colorado For proposal guidelines or information, contact: Due date for symposia Edna Collis, Continuing Education Coordinator, GSA headquarters, and theme proposals: 1-800-472-1988, ext. 134, [email protected] January 6, 1999

CALL FOR FIELD TRIP PROPOSALS We are interested in proposals for single-day and multi-day field trips ORDER FORM—1998 GSA Abstracts with Programs beginning or ending in Denver, and To purchase copies of GSA Abstracts with Programs, you may use this form. Prepayment dealing with all aspects of the geo- is required. Members, provide member number and deduct your 20% discount. sciences. Please contact the Field Trip Check your records to make sure you have not previously purchased any of these publications Co-Chairs: on your dues statement, or through Publication Sales. No refunds for duplicate orders. Alan Lester List Meeting Meeting Dates Price Quantity Amount Department of Geological Sciences University of Colorado Northeastern 3/19–3/21 $15 $ Campus Box 399 North-Central 3/19–3/20 $15 $ Boulder, CO 80309-0399 South-Central 3/23–3/24 $15 $ (303) 492-6172 fax 303-492-2606 Southeastern 3/30–3/31 $15 $ [email protected] Cordilleran 4/7–4/9 $15 $ Rocky Mountain 5/25–5/26 $15 $ Bruce Trudgill Department of Geological Sciences Annual Meeting (Toronto) 10/26–10/29 $38.75 $ University of Colorado Check here if GSA Member Total $ Campus Box 399 Members deduct 20%. It will not be applied later. ➝ –20% $ Boulder, CO 80309-0399 (303) 492-2126 Member # ______TOTAL $ fax 303-492-2606 SHIP TO: [email protected] Name ______Address ______FUTURE MEETINGS Address ______2000 Reno, Nevada City______State ____ ZIP ______Daytime Phone ______November 13–16 2001 Boston, Massachusetts METHOD OF PAYMENT: November 5–8 CHECK or MONEY ORDER (payable in U.S. funds on U.S. bank) Credit Card (Please print information) 2002 Denver, Colorado October 28–31 MC VISA AmEx Diners (circle one) Exp. Date ______For information on any GSA Card No. ______Meeting call the GSA Meetings Signature of Cardholder ______Department. 1-800-472-1988 or TO ORDER BY MAIL: Send this form to GSA Publication Sales, P.O. Box 9140, Boulder, CO 80301-9140 (303) 447-2020, ext. 113 TO ORDER BY PHONE OR FAX using a major credit card [email protected] fax (24 hour line): 303-447-1133; or phone (303) 447-2020 or 1-800-472-1988 (8:00 a.m. to 4:30 p.m. MT) Or see GSA’s Web page at TO PLACE AN ELECTRONIC ORDER: Visit our Web site at www.geosociety.org http://www.geosociety.org ON-SITE PURCHASES may be made in the registration area. Supplies are limited.

GSA TODAY, May 1998 29 CALENDAR

April Only new or changed information is Timing and Displacement, Winthrop, Washing- April 26–28, Thrust Tectonics 99, Egham, Sur- published in GSA Today. A complete listing ton. Information: J. Brian Mahoney, Department of rey, UK. Information: K. R. McClay, Royal Holloway can be found in the Calendar section on Geology, University of Wisconsin, Eau Claire, WI University of London, Egham, Surrey TW20 0EX, the Internet: http://www.geosociety.org. 54702-4004, (715) 836-4952, fax 715-836-2380, [email protected]. UK, phone 44-1784-443618, fax 44-1784-438925. 1998 Penrose Conferences August May August 17-22, The Marine Eocene-Oligocene May 26–28, Geological Association of May Transition, Olympia, Washington. Information: Canada–Mineralogical Association of May 14–18, Linking Spatial and Temporal Donald R. Prothero, Department of Geology, Occi- Canada Joint Annual Meeting, Sudbury, Scales in Paleoecology and Ecology, dental College, 1600 Campus Road, Los Angeles, Ontario. Information: P. Copper, Dept. of Earth Solomons, Maryland. Information: Andrew S. CA 90041, (213) 259-2557, fax 213-259-2704, Sciences, Laurentian University, Sudbury, Ontario Cohen, Dept. of Geosciences, University of [email protected]. P3E 2C6, Canada, (705) 675-1151, ext. 2267, fax Arizona, Tucson, AZ 85721, (520) 621-4691, 705-675-4898, [email protected]. fax 520-621-2672, [email protected]. 1998 Meetings June June June 6–9, 37th U.S. Rock Mechanics Sympo- June 4–12, Evolution of Ocean Island Volca- June sium, Vail, Colorado. Information: ExpoMasters, noes, Galápagos Islands, Ecuador. Information: June 25–26, Western United States Earth- 7632 E. Costilla Ave., Englewood, CO 80112, Dennis Geist, Dept. of Geology, University of quake Insurance Summit, Sacramento, Califor- (303) 771-2000, fax 303-843-6212, mcramer@ Idaho, Moscow, ID 83844, (208) 885-6491, nia. Information: Western States Seismic Policy expomasters.com. fax 208-885-5724, [email protected]. Council, 121 Second St., 4th Floor, San Francisco, CA 94105, (415) 974-6435, fax 415-974-1747, June 21–24, International Gemological Sym- July [email protected], www.wsspc.org/summit. posium, San Diego, California. Information: Dona July 4–11, Processes of Crustal Differentia- Dirlam, Gemological Institute of America, 5345 tion: Crust-Mantle Interactions, Melting, September Armada Dr., Carlsbad, CA 92008, (760) 603-4154, and Migration Through the Crust, September 3–6, 1998, Earth Stress and Indus- fax 760-603-4256, [email protected]. (Abstract Verbania, Italy. Information: Tracy Rushmer, Dept. try–The World Stress Map and Beyond (poster) deadline: October 1, 1998.) of Geology, University of Vermont, Burlington, (Euroconference), Heidelberg, Germany. Infor- mation: WSM Euroconference Office, Geophysical July VT 05405, (802) 656-8136, fax 802-656-0045, July 11–16, Meteoritical Society 62nd Annual [email protected]. Institute, University of Karlsruhe, Hertzstraße 16, 76187 Karlsruhe, Germany, fax: 49 721 71173, Meeting, Johannesburg, South Africa. Informa- September [email protected]. tion: W. U. Reimold, Dept. of Geology, University September 13–17, Ophiolites and Oceanic of the Witwatersrand, Private Bag 3, P.O. Wits Crust: New Insights from Field Studies and September 9–14, Association of Earth Science 2050, Johannesburg, South Africa, phone 27 11 Ocean Drilling Program, Marshall, California. Editors–European Association of Science Edi- 716 2946, fax 27 11 339 1697, 065wur@ Information: Yildirim Dilek, Dept. of Geology, tors–Council of Biology Editors–GeoInfo VI, cosmos.wits.ac.za. Miami University, Oxford, OH 45056, (513) Washington, D.C. Information: Barbara Haner, Sci- 529-2212, fax 513-529-1542, [email protected]. ence & Engineering Library, 4697 Geology Bldg., Send notices of meetings of general interest, in University of California, Los Angeles, CA 90095, format above, to Editor, GSA Today, P.O. Box 9140, 1999 Penrose Conferences (310) 825-1055, [email protected], or Boulder, CO 80301, E-mail: [email protected]. http://earth.agu.org/editorinfo98. January January 18-24, Strike-slip to Subduction Tran- sitions on Plate Boundaries: Tectonic Set- 1999 Meetings ting, Plate Kinematics and Seismic Hazards, January Puerto Plata, Dominican Republic. Information: January 24–27, Conference on Tailings and Things To Do Paul Mann, Institute of Geophysics, University of Mine Waste, Fort Collins, Colorado. Information: Texas, Bldg 600, 4412 Spicewood Springs Road, Linda Hinshaw, Dept. of Civil Engineering, Col- in Denver … Austin, TX 78759-8500, (512) 471-0452, fax orado State University, Fort Collins, CO 80523- Internationally known computer expert 512-471-8844, [email protected]. 1372, (970) 491-6081, fax 970-491-3584 or 7727, [email protected]. (Abstracts deadline: Betty Gibbs, publisher of Earth Science March Computer Applications (formerly Comput- March 25-31, Mid-Cretaceous to Recent Plate June 12, 1998.) ers & Mining) will coordinate a display in Boundary Processes in the Southwest March Pacific, Arthur’s Pass, South Island of New March 1–3, 13th International Conference the 1998 mining and minerals exhibit at Zealand. Information: Suzanne L. Baldwin, and Workshops on Applied Remote Sensing, the Festival of Mountain and Plain–A Department of Geosciences, University of Vancouver, British Columbia. Information: ERIM Taste of Colorado in downtown Denver Arizona, Tucson, AZ 85721, (520) 621-9688, Geologic Conferences, Box 134008, Ann Arbor, over Labor Day weekend this year. The fax 520-621-2672, [email protected]. MI 48114-4008, (734) 994-1200, ext. 3234, fax Computer Science Learning Center will June 734-994-5123, [email protected], http:// www.erim-int.com/CONF/conf.html. (Abstracts involve hands-on hardware with soft- June 18-24, Terrane Accretion along the ware on exploration, mining, reclama- Western Cordilleran Margin: Constraints on deadline: July 13, 1998.) tions, etc. Volunteers are needed to help Gibbs set up the display and describe modern Friends of Paleobiogeography To Meet exploration, mining, processing, and Friends of Paleobiogeography, formed in 1996, works on (1) developing a consensus on reclamation technologies to exhibit the principles of paleobiogeographic classification and nomenclature of paleobiogeo- attendees (estimated to be 40,000 graphic units (biochores) that are congruent with neobiogeography, and (2) applying people). those principles to published biochores by compiling all named units on a single set of If you are willing to help with this high- maps and analyzing synonymies and homonymies. impact public education project, please The group, led by Gerd E. G. Westermann, McMaster University, plans to meet at major contact Betty Gibbs ([email protected], national and international conferences, including the 1998 GSA Annual Meeting in http://www.csn.net/~bgibbs/erthsci/) or Toronto, Ontario, in October. Guy Johnson, exhibit coordiantor for the Colorado Mining Exhibit Foundation at For more information, contact Westermann at School of Geography and Geology, (303) 969-0365, fax 303-716-0503, McMaster University, Hamilton, Ontario L8S 4M1, Canada, [email protected]. [email protected].

30 GSA TODAY, May 1998 CLASSIFIED ADVERTISING

Published on the 1st of the month of issue. Ads (or can- information contact Jim Butler at . SYSTEMS PERFORMANCE cellations) must reach the GSA Advertising office one KU is an EO/AA employer. ANALYST (GEOSTATISTICS) month prior. Contact Advertising Department (303) GG 11/12 ($39,270-$61,190) 447-2020, 1-800-472-1988, fax 303-447-1133, or E-mail: RESEARCH GEOLOGIST The U.S. Nuclear Regulatory Commission is currently [email protected]. Please include complete IDAHO GEOLOGICAL SURVEY seeking a Systems Performance Analyst for our Rockville, address, phone number, and E-mail address with all cor- The Idaho Geological Survey (IGS) invites applications for MD location. Responsibilities include evaluating, integrat- respondence. a Research Geologist. The IGS is the lead agency in the ing and applying geostatistical methods in system perfor- state for the collection, interpretation, and dissemination of mance assessments of radioactive waste disposal facili- Per line all geologic and mineral information for Idaho. As a Spe- ties; applying the results of these assessments to the Per Line for each cial Program of the university of Idaho, the IGS evaluation of evolving statutory requirements, environ- for addt'l month researches the state's geology and its mineral resources mental standards, environmental impacts, and regulatory Classification 1st month (same ad) and provides geologically related services to the public. criteria relevant to NRC’s waste management and decom- Situations Wanted $1.75 $1.40 The position requires a scientist who is capable of under- missioning programs; and developing technical positions Positions Open $6.50 $5.50 taking research into the basic geologic framework of the and review plans for implementation of performance Consultants $6.50 $5.50 state, with an emphasis on publishing studies useful to the assessment. Services & Supplies $6.50 $5.50 state's citizens. Requires BS/BA or equivalent combination of educa- Opportunities for Students Qualified candidates will demonstrate an ability for out- tion, training, and experience; and at least 1 year experi- first 25 lines $0.00 $2.35 standing field research and geologic mapping, indicate a ence at next lower grade level. additional lines $1.35 $2.35 background and interest to obtain externally funded pro- Additional information and application materials should Code number: $2.75 extra grams, and exhibit excellent written and oral communica- be obtained by calling the NRC Personnel Smartline at tion skills. Qualified candidates also will demonstrate an (800) 952-9678. Refer to Vacancy Announcement Agencies and organizations may submit purchase order or interest in and an ability to interact with industry, local, R9848017. Please send your resume or Federal applica- payment with copy. Individuals must send prepayment state, and federal agencies, educational institutions, the tion (OF-612) and statement addressing rating factors and with copy. To estimate cost, count 54 characters per line, general public, and professional collegues. The successful salary history, no later than 05/11/98 to: U.S. Nuclear including all punctuation and blank spaces. Actual cost applicant will conduct research and perform service with Regulatory Commission, Office of Human Resources, may differ if you use capitals, centered copy, or special little direct supervision, and will participate in the pursuit of Attn: Tammy Simmons (Dept. A-98104), Mail Stop: T2- characters. funding for IGS programs. D32, Washington, DC 20555. EOE, M/F/D/V. U.S. citizen- A Ph.D. in geology is required. Candidates with experi- ship required. To answer coded ads, use this address: Code # ----, ence and expertise in field geology and geologic mapping GSA Advertising Dept., P.O. Box 9140, Boulder, CO are preferred. Experience investigating the geology and HARVARD UNIVERSITY 80301-9140. All coded mail will be forwarded within ore deposits of Idaho is desirable. Applicants experienced DEPARTMENT OF EARTH & PLANETARY SCIENCES 24 hours of arrival at GSA Today office. in using computers for word processing, graphics, data JUNIOR FACULTY POSITION manipulation, and in using the Internet are preferred. The Department of Earth and Planetary Sciences at Har- Interested persons should send a letter of application, cur- vard University seeks to fill a tenure-track position at the Positions Open riculum vitae, separate statements of research interests assistant or untenured associate professor level. We are and philosophy of geological service to the public, and the interested in candidates who investigate the processes names, addresses, telephone numbers, and e-mail and evolution of the Earth and planets through studies of GEOMORPHOLOGY POSITION addresses of three references to: Kurt Othberg, Search the physical and chemical properties of rocks, minerals UNIVERSITY OF ARIZONA Committee, Idaho Geological Survey, University of Idaho, and melts. The incumbent will be expected to develop a The Department of Geosciences at the University of Ari- Moscow, ID 83844-3014. Search will be closed when a strong research program and to teach at the undergradu- zona invites applications for a tenure-track appointment in sufficient number of qualified applicants have been identi- ate and graduate levels. Applicants should send a state- geomorphology, preferably at the assistant professor fied, but not earlier than April 30, 1998. The IGS and the ment of research and teaching interests, curriculum vitae level. A Ph.D. or equivalent degree is required. University of Idaho are equal opportunity/affirmative action and the names of three referees to Prof. Roberta Rudnick, We seek applicants with a strong background in geo- employers. Applications from women and minority groups Chair, Petrology Search Committee, Department of Earth morphology, with expertise in one of several sub-disci- are strongly encouraged. and Planetary Sciences, Harvard University, 20 Oxford plinary areas including, but not confined to, tectonic, fluvial Street, Cambridge, MA 02138. Applications should be or glacial geomorphology. Preference will be given to can- THE UNIVERSITY OF NEW BRUNSWICK received by September 15, 1998. We particularly encour- didates with a strong record of publication and potential ECONOMIC GEOLOGIST age applications from women and minorities. For more for obtaining research funding. Commitment to undergrad- Applications are invited for the CHAIR IN ECONOMIC information about the department you may visit our web uate and graduate education is essential, and preference GEOLOGY to be appointed at the Assistant Professor stie at: www.eps.harvard.edu will be given to candidates with demonstrated teaching level. The position is at this time supported for a 4 year ability. term. As a priority position within the Department and Fac- The Department of Geosciences is strongly committed ulty of Science, it is intended to establish the Chair as a Services & Supplies to excellence in surface process studies, partly through tenure-track position at the earliest possible date. Respon- LEATHER FIELD CASES. Free brochure, SHERER collaboration with allied units on campus, including sibilities will include undergraduate and graduate teaching CUSTOM SADDLES, INC., P.O. Box 385, Dept. GN, Hydrology, and Soils, Water, and Environmental Sci- covering resource exploration, evaluation and develop- Franktown, CO 80116. ences, where searches in fields closely related to geomor- ment. The Department of Geology supports Geology, phology are being developed, the Tree-Ring Laboratory, Environmental Geochemistry and Geological Engineering and the U.S. Geological Survey. programs, to which all faculty contribute. The Department Opportunities for Students The selection process will begin July 1, 1998 and con- is particularly seeking a candidate who can integrate into Graduate Research Assistantships in Earth Surface tinue until the position is filled. Interested applicants and complement existing research interests. Candidates Processes. Research assistantships are available at Iowa should submit a curriculum vitae, a statement of research must have a Ph.D. at the time of appointment, with a State University for motivated Ph.D. and M.S. students and teaching interests, and a list of at least three refer- strong background in some aspect of mineral deposits with interests in glaciology, geomorphology, or environ- ences with addresses, e-mail, phone, and fax numbers to: geology (e.g. mineral exploration science, stable isotopes, mental geology. Research opportunities include field Professor Joaquin Ruiz, Chairman, Department of Geo- ore genesis). The successful candidate is expected to experiments on glaciers in Norway, laboratory and field sciences, The University of Arizona, Tucson, AZ 85721, develop a research focus on mineral deposits and other studies of sediment deformation beneath glaciers and on PH: (520) 621-6024, FAX: 520-621-2672; [email protected] economic/resource geology topics through an externally- hillslopes, and field studies of gully development in loess zona.edu. funded research program. soils. For more information, contact Dr. Neal Iverson, The University of Arizona is an EEO/AA employer. The Department of Geology is involved in rejuvenation Department of Geological and Atmospheric Sciences, M/W/D/V. of its faculty and anticipates significant opportunities for Iowa State University, Ames, IA 50011. 515-294-8048. the successful candidate. Research facilities include e-mail: [email protected]. Departmental web site: HYDROGEOLOGIST microprobe, analytical SEM & TEM, XRD, high-tempera- http://www.geology.iastate.edu Kansas Geological Survey, Univ. of Kansas, Lawrence. ture geochemistry lab, AA/graphite furnace/ICP and GIS Full-time position on KU staff at faculty-equiv. rank of lab. Given suitable candidates, the position is available as assistant or associate scientist depending on qualifica- of July 1, 1998. It is intended to fill the position by tions. Requires Ph.D. (or expected within 6 months) with January 1, 1999. In accordance with Canadian immigra- hydrogeology emphasis. Research/publications on simula- tion requirements, this advertisement is directed to Cana- ADS GET tion of physical/biochemical processes affecting transport dian citizens and permanent residents. Applicants are in porous media supplemented with practical experience. asked to provide a curriculum vitae, a statement of teach- Background in stochastic applications to gw flow/transport ing and research plans, and arrange for three letters of RESULTS! is desirable. The Geohydrology Section has 9 full-time recommendation to be sent directly to: Dr. Joseph C. professionals with additional support personnel. Emphasis White, Chair, Department of Geology, University of New CONTACT on state-of-the-art field studies and complementary theo- Brunswick, 2 Balley Drive, Fredericton, NB E3B 5A3 retical research. Opportunity to pursue individual and CANADA. GSA Today Advertising cooperative research of relevance to Kansas and The University of New Brunswick is committed to the P.O. Box 9140 teach/advise students at KU. Complete announcement principle of Employment Equity. Boulder, CO 80301 available from S. Cox, Personnel Services (785) 864-3965 303-447-2020 x153 • 1-800-472-1988 or from . Ref: 98W0189. Application deadline: June 1, 1998, postmark. For further [email protected]

GSA TODAY, May 1998 31 Call for Papers April GSA Today Abstracts Due July 13 Preregistration Due September 18 Registration and Housing Information June GSA Today Program Schedule September GSA Today and the Web FOR INFORMATION: GSA Meetings Department, P.O. Box 9140, Boulder, CO 80301, • (303) 447-2020, (800) 472-1988, [email protected], http://www.geosociety.org 1998 ANNUAL MEETING AND EXPOSITION October 26–29, 1998 Tectonics AND ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■ OF THE NortheasternNortheasternNortheastern Geochemistry Caribbean ■ edited by ■ Edward G. Lidiak and ■ David K. Larue, 1998

This up-to-date account of the geology of the northeastern Caribbean plate boundary region is the first general summation of this region since the publication of the DNAG series volume (H) on the Caribbean region (1990). The primary focus of this Special Paper is on the tectonics and geochemistry of the plate boundary, with emphasis on the island of Puerto Rico, the Puerto Rico trench, and adjacent areas. Following an introduc- tory chapter on tectonic setting and stratigraphic correlations of the vol- canic strata in Puerto Rico, five papers deal with geochemical aspects of these and related igneous rocks. A second group of three papers deal pri- marily with the tectonics and stratigraphy of Tertiary and younger rocks along the north coast of Puerto Rico and in the adjacent Puerto Rico trench. This is essentially a companion to GSA Special Papers 262 and 295; all three concern the circum-Caribbean plate margins. SPE322, 222 p., indexed, ISBN 0-8137-2322-1, $68.00, Member price $54.50 Volume is 8-1/2" x 11" paperback. Price includes shipping and handling. 1-800-472-1988 www.geosociety.org GSA Publication Sales P.O. Box 9140, Boulder, CO 80301 303-447-2020; fax 303-447-1133