GSW: 1989 MEETING MINUTES

 

MINUTES OF THE GEOLOGICAL SOCIETY OF WASHINGTON

1182nd meeting, 11 January 1989--Or the return to the sort of renovated and recently progressive so to speak Cosmos Club.

President Hanshaw called the meeting to order at 8:05 PM.  The minutes of the 1181st meeting were approved as read. Visitors and guests were Wayne Gambell, Jamie Lisa, Elanor O'Leahy, Jeremy McFine, J. K. Golpy, Dave Grove, and Judy and Tom Triblehorn.   New members elected at the council meeting were Phillip Molling (USGS), Roberta G. Dillenberg (USGS), Linda J. Winegrad (AGI), Christopher Newhall (USGS), Virgil Frizzell (AGU Congressional Science Fellow; USGS), and Marilyn Suiter (AGI).

     Bill Leo made two announcements. Volunteers that can demonstrate how real scientists work and think are needed for Science Discovery Day for Fairfax County 4th and 6th graders; please call 759-6784 if you feel qualified.   Also Earth Day is scheduled for 1 to 4 March at a local high school and will feature scientific demonstrations and lectures.   Call Bill Leo at 648-6927 for additional information.

     Pete Stifel announced that the Department of Geology at University of Maryland is also searching for a geologist who can work and think to serve as Department Chairman, and nominations from the GSW ranks are invited.   In summary, please contact your favorite U. Md faculty member if you know of someone with these qualifications, or Bill Leo if you have them yourself.

     President Hanshaw mentioned that she had a quick introduction to the tough job ahead as GSW president when on her first day she received a strongly worded complaint from Robin Britt objecting to the awarding of the Sleeping Bear to now past president Doug Rumble.   Whether he deserved the famed award was not questioned, only whether it could be given to a serving president. After a thorough investigation, Hanshaw dispatched Britt, and Rumble still has the bear.

     So our loyal members will not have to miss the annual GSA meeting in St Louis,  the November 8 meeting of the GSW has been moved to November 15.

     President Hanshaw also made several announcements regarding IGC: members who wish to provide bed and breakfast to foreign students please see George Helz; members who wish to donate their warm bodies as volunteers at the convention please see Jack Epstein, and because GSW will be a sponsor; members who wish to donate anything green, please see any officer of the society.

     Finally,  President Hanshaw announced that the council voted to issue certificates of appreciation to all of our active members who have been with the society for 50 years or more.

     There were no informal communications.

     The first talk was by Warren Wood of the USGS on Solutes, Lakes, and Groundwater and the origin of non-marine evaporite deposits in closed-basin lakes in general and the Ogallala Basin, Texas, specifically.   Wood noted that the compositions of many deposits are commonly not the same as the composition of solutes that enter the lakes and that only 2 or 3 minerals are commonly deposited, not 20 or so as would be predicted from equilibrium geochemical calculations based on the composition.   The solution: closed lakes may not really be closed as imposed density changes drive groundwater flow between basins and selectively remove Mg, C1, and K, in particular from the upstream lakes.   This geological hand me down process is evident in the chemistry of the Lakes in the Ogallala basin.   Questions from E-an Zen, anonymous, George Helz, Dave Stewart, Gene Robertson, Rob Robertson, Blair Jones, and Dave Milton, all USGS.

     The second talk was by Nick Oliver of the Geophysical Lab on evidence for focused metamorphic fluid flow in an amphibolite terrane in northern Australia.   Fluid heterogeneities are evident on small and large scales as extensively altered rocks are complexly interspersed with unaltered rocks. Scapolite, an indication of extensive alteration, is particularly abundant near gabbroic bodies.   Oliver suggested strain shadows around these large, rheologically strong gabbroic bodies within the weaker metasedimentary rock terrane focused fluid flow.   Thus another geologic paradox results:  a rigid sponge.   Numerical modeling was used to demonstrate that such a sponge was possible.   As a result, Oliver suggested, fluid pressures may vary significantly in space and time during regional metamorphism.   Questions from Sorena Sorensen, Eileen McLellan, Doug Rumble, Brooks Hanson, and Gene Robertson.

     The third talk was by Phil Candella and Steve Bouton, both at University of Maryland, on W-Mo mineralogenesis and the role that magmas play in the chemistry of W and Mo ore deposits.  Laboratory experiments suggest that fO2 is a critical parameter in the fractionation of W and Mo between melt and crystals in felsic magmas.   In reduced magmas, W is more incomparable;  in contrast Mo is incompatible in oxidized magmas.   These data are consistent with field observations of the tendency for W deposits to occur in association with reduced granites.   Questions from Sorena Sorensen, E-an Zen, and Robin Britt.

     President Hanshaw adjourned the meeting at 10:01 PM, 88 members and guests in attendance.

     [signed R. Brooks Hanson]

 

MINUTES OF THE GEOLOGICAL SOCIETY OF WASHINGTON

1183rd meeting, 25 January 1989

     President Hanshaw tried to organized the meeting at 7:59:07;  the meeting would have started exactly on time, except that she continued her policy of confrontation with past presidents of the society, this time raising the ire of E-an Zen.   Last time it was Robin Britt.   E-an,  it seems, objected to such an enthusiastic start, or needed a little extra time to situate himself.   In any case, after some muffled discussion and a quieting glance,  the score is now President Hanshaw 2, past presidents 0, and the word is out: For those who want to imbibe in the refreshments, come early or bring a large cup.

     Once E-an Zen finally allowed the meeting to proceed,  the minutes were read and approved.   Visitors Al Dougan and Bob Height were introduced; new members  Hendrik G. Van Oss and Ellen O'Leary were elected with a rare continuous vote before during and after the meeting as council members drifted in.

     Jack Epstein again announced that IGC is coming and volunteers are needed. Duties and Benefits have finally been decided on until at least next week. Especially needed are people to work in the workshops, put up posters, drive vans and translate on a technical/nontechnical basis.   Student benefits for 1-day of work include: a waiving of the registration fee,  lunch,  tickets to picnic, and the all important letter of appreciation.    Students in particular are encouraged to apply.

     No informal communications.   This must be a slow year for new short ideas.

     The first talk was by Dave Lambert of DTM on Sr, Nd, Pb--actually pronounced Os--isotopic investigations of the Stillwater Complex, Montana. These tracers provide information on the compositions of different magmas injecting into the intrusion and their relation to platinum group element ore deposits.   The isotopic data preclude derivation of the Stillwater from a single magma.   Two magmas an A-type and a U-type were involved;  the A-type was low in S and the PGE's were incompatible.    The mixing of the two magma types allowed the PGE's to distill and be incorporated in the famous JM reef. Thus, the Stillwater was actually quite dynamic. Questions by Sorena Sorensen and E-an Zen.

     The second talk was by Jack C. Reed, Jr. on the Development of Continental Crust in the Colorado Province.    Reed, from the USGS at Denver, was quick to point out that unlike Denver,  the other main USGS branches, were not actually part of the North America Craton.   The 1800-1650 million year old Colorado province extends from Sonora to Missouri to the Achaean Wyoming craton in the north,  across the deformed Cheyenne belt.   In contrast to earlier interpretations, new U/Pb data indicate a long magmatic history and a possible evolution as a magmatic arc;   deformation and sillimanite grade and andalusite-cordierite metamorphism were apparently diachronous.   Southward subduction of oceanic crust beneath the Colorado province can account for its tectonic setting as well as its final suturing with the Wyoming province,  thus forming the Cheyenne belt.   A point not made, but perhaps implied is that this geometry leaves Denver situated tectonically above the rest of Precambrian north America.   But depending on Paleozoic and Mesozoic subduction geometries Menlo Park and Reston might actually be situated tectonically above Denver.   I feel that this superposition theory perhaps best explains many of the tectonic theories emanating from workers at the various branches.   Questions by Paul Lowman, Sorena Sorensen, Doug Rankin, and repeated questions from E-an Zen, who had clearly rebounded from his earlier defeat.

     Craig Schiffries next presented a tour of hydrothermal processes in layered intrusion,  specifically the Bushveld.   Schiffries presented evidence that high temperature veins that formed at temperatures up to 900C are much more abundant in this huge intrusion than previously recognized.   The primary layering in many areas is not the classic banding, but mineralized veins. Toward the veins,  igneous Px is altered, and fresh hydrothermal Px has developed.   This intrusion thus cracked extensively as it cooled.   Questions from Doug Rumble, anonymous, Charles Gilbert, E-an Zen, and Dave Stewart.

     President Hanshaw adjourned the meeting at 9:39 without further complaints.   68 in attendance.

     Respectfully submitted,

     R. Brooks Hanson

 

Geological Society of Washington

Minutes of the 1184th Meeting,

8 February 1989

     President Hanshaw called the meeting to order at 8:09 PM, apologizing for the late start.   The minutes of the 1183rd meeting were approved as read.   New members Libby Prueher, Charles Druitt, Roland Pool, Alan Geralniok, and Alan Batcheller were announced.   Guests included John Carter, Jeff McCannicker, John Brady, Martha Gertes, Cortney Wilkeson, Don Collins, and Scott Owenger. There were several brief announcements: Bill Leo made a plea for volunteers to help with Science Fairs.   Judging is on Saturday mornings for approximately 3 hours.   There was an additional comment that all schools are desperate for science fair judges and appointments are extremely are essentially assured upon application.   That some meeting cards were apparently distributed late will be looked into by President Hanshaw.   Finally,  the IGC is still coming.

     Roz Helz presented the first informal, but thoroughly prepared, communication of the year on data from an ongoing melt-fishing expedition on Kilauea lava lake, Hawaii. Data from two new drill holes confirm that the lake, which formed in 1959,  is hotter than its supposed to be, and deeper.   The melt zone migrated down less than predicted, but the bottom of the lake migrated more than expected, which means that it was not where it was supposed to be. The extra depth can be explained by a malfunction in with seismologists, who suggested that the lake floor did not drop during the 1959 eruption because of a lack of an appropriate seismic signal.   Questions from Pete Tillman [Toulmin?] and Tom Simkin.

     The first talk was by Harold Borns on the ages and character of the Gondwana Talchir glaciation, Penninsula India. Whereas Helz showed that lake floors can move, Borns showed that classic Gondwana tillites can simply disappear.   Specifically, many of the classic Gondwana glacial deposits that have been used to indicate glaciation and chaotic directions of flow, may actually be mudflows, albeit of reworked glacial material.   Identification of the true glacial deposits gives a coherent picture of 4 continental glaciations, but the time can only be constrained as pre-Early Permian.    Questions from Charles Pruitt, Doug Rankin, Sorena Sorensen, Blain Cecil twice, and Dave Stewart.

     David Anastasio next talked on thrusting, halotectonics,  and sedimentation in the Spanish Pyrenees.   Dr. Anastasio suggested that doubly plunging anticlines in the southern Pyrenees with anomalous orientations across strike were formed by salt doming.   Stratigraphic studies suggest that the domes apparently developed diachronously from west to east in response to Eocene deformation emanating from the Hercynian core.   The salt in the domes, now locally several kilometers thick, was deposited in an extensional tectonic setting during the Mesozoic.   Dave Stewart, Gene Robertson, and Charles Pruitt peppered Anastasio with questions.

     John Filson, one of 18 U.S scientists invited by Russia to assist in the recovery and collect data after the recent magnitude 6.8 earthquake in Armenia, next described the geology of the region,  the event, and the aftermath.   Yet again things were not what they first appeared:   First motion studies indicate that slip was dominantly right lateral with a small component of thrusting.   In contrast, most exposed faults appear to be thrust faults associated with the continued northward slamming of the Arabian plate, and historical events have generally been purely thrust events. Although the Russians knew of the seismic hazard of the region and had designed regulations, plans were not followed through, and that, along with bad luck--the earthquake occurred only minutes before schools would have had recess--led to the magnitude of the tragedy.   Use of prefabricated multisection floors may have contributed to much of the loss of life in damaged multistory buildings.   Questions from Gene Robertson, Pete Stifel, Pete Pouleman [Toulmin?], Penny Hanshaw, and unidentified.

     In summary,  in the 1184th meeting was concerned with things that are not anymore:   lake floors, tillites, regional anticlines, and, alas, whole cities. The meeting was adjourned at 10:08; 68 in attendance.

     Respectfully submitted

     R. Brooks Hanson

 

GEOLOGICAL SOCIETY OF WASHINGTON

Minutes of the 1185th meeting, 

22 February 1989

     President Hanshaw called the meeting to order at 8:02 PM and noted that despite ominous rumors of snow, the audience was large (91 to be exact). The minutes of the 1184th meeting were read and approved, and guests Tim Johnson and Rich Kyle were introduced.

     E-an Zen announced that several movie/videotape field trips would be shown.   If you are interested in seeing Los Angeles-LA the movie, films of the Voyager Miranda encounter, or Viking Mars encounter, too bad because the showing was last Wednesday.

     Bruce Hanshaw next brought us up to date on preparations for the IGC.   So far there are 2200 registrant from 90 countries,  200 sponsors who have donated 1.5 million dollars, and 900 registrants for field trips.   Unfortunately,  some field trips had to be cancelled, but this is really not surprising to anyone who tried to read all of the prospective field trips in the second circular in one sitting.   President Bush may open the Congress.    Washington natives have prepared evacuation plans.   Finally, please don't forget the Bed and Breakfast program. If you did, please see George or Roz Helz for an explanation.

     Ben Burden gave the second informal communication of the year on a new synthesis of the plagioclase phase diagram that accounts for all of the immiscibility gaps.   The key structures of the diagram are a doubly protruding immiscibility field.   The minimum between the two immiscibility gaps is created by an almost stable phase that lowers the free energy of a particular plagioclase composition.

     Donald Hoskins from the Pennsylvania Geological Survey first talked on "A geological map mystery.   Through good luck and diligent research, Hoskins was able to put together a fascinating geological soap opera concerned with the publication of the first state geologic map of Pennsylvania and the personalities, quarrels,  loves and hates, of William Rodgers,   J.P. Leslie and W. Williams.   The plot is simple, but may sound familiar: Rodgers and Leslie originally worked together, but it seems Rodgers was taking all of the credit for Leslie's hard field work.   The twist is that he was designated to take the credit by the Pennsylvania legislature (that is, he was the PI).   When Leslie tries to publish the map on his own, Rodgers applied for an injunction claiming that his map had been pirated.   In the end, Rodgers gets the map and all Leslie can do is write nasty books criticizing Rodgers and his most extreme scientific theft.   Questions from Bruce Hanshaw and E-an Zen and Wade Boggs who wanted to know why Rodgers got off so easily.

     Patrick Okita next talked on the origin of sedimentary manganese carbonate ore deposits.   Deposition of these deposits is thought to occur where a redox boundary intersects a topographic high--his was appropriately called the bathtub ring model before some other editors had their say.   These deposits are typically hosted by marine rocks, are finely laminated, nonfossiliferous except for radiolarians and contain trace amounts of pyrite.   Deposits are characterized by negative C and positive S isotopic anomalies and a low organic content.   These and other geochemical data are consistent with reducing conditions during deposition and possible interaction with pore waters.  Questions from George Helz, Sorena Sorensen, Greg McKelley, and Jeff Mackinnon.

     Anne Wiley presented the final talk on Asbestos and the Law.   Wiley demonstrated that asbestos laws extend to much more than what geologists would call asbestos, and this situation is causing all sorts of legal, political, and social headaches.   In response to fears that asbestos causes cancer, OSHA, on little scientific evidence, originally defined asbestos primarily on the basis of particle size in minerals that potentially could have asbestiform habits.    In the black and white OSHA world, all particles with an aspect ratio of 3:1 are asbestos:   this is the law.   The problem is that as a result of this law many more particles are classified as asbestos than actually should be, and since the law was passed in 1971,  the definition has actually been expanded even as evidence of which asbestos minerals cause cancer and what actually characterizes true asbestos has been obtained.   This black and white situation leads to a lot of gray--that is waste--in public policy, which may makes lawyers happier, but is a special problem for the mining industry, which is now always producing legal asbestos, schools, and so forth.    An even stickier problem is that most of the techniques used to detect legal asbestos do not collect true asbestos.   Questions from Charles Druitt, Pat Ross, Pat Shoneys, Doug Kinney, E-an Zen, Jim McNeil, Anonymous, and Tim Johnson.

     Before President could adjourn the meeting, Bill Leo, who was ignored earlier, jumped up to give a belated announcement that judges are still needed for Science fairs particularly on March 18.   President Hanshaw finally did adjourn the meeting at 10:05 PM.

     Respectfully submitted

     R. Brooks Hanson

 

THE GEOLOGICAL SOCIETY OF WASHINGTON

Minutes of the 1186th meeting,

8 March 1989.

     President Hanshaw called the meeting to order at 8:05 PM;  this time E-an Zen complained that the meeting was five minutes too late.   At an earlier meeting he had strongly objected to an overly prompt call to order.   Lacking an appropriate excuse, President Hanshaw simply ignored the complaint and continued with the meeting.   The Minutes of the 1185th meeting were read and approved.   New members that were supposedly elected some time during the meeting as council members drifted in were Charles Druitt, James Trefil, Sue Cox, Jerome Machamer, and Thomas Jones.   Lee Silver, Lasa Shuta, Jeff Ryan, Jeff Lann,  Gerry Tango, Jim Emery,  and Debbie Powell were introduced as guests.

     George Helz mentioned that a dozen geohosts that can house foreign visitors during the IGC are still needed.   If you did not receive a letter describing the program and might have room for a visitor during the hectic days of July 9 to 19 see George Helz as soon as possible because volunteers were needed by last week.

John Slack presented an informal communication describing unusual mineral compositions from a granulite terrane at Broken Hill Australia.   This granulite terrane contains abundant strata-bound tourmaline; On the basis of microprobe analyses and textural relations, boron-bearing biotite seems to have formed during the retrograde breakdown of tourmaline.    Questions from Dan Milton and Doug Rumble.

     Jonathan Patchett presented the first talk on New light on the origin of Precambrian rocks in the midcontinent.   Patchett described isotopic data from Grenville-like rocks in Mexico and Texas, primarily, and related the formation of these rocks to a suite of supposedly anorogenic granites in the continental interior.   Most Grenville rocks are enriched in radiogenic Nd compared to older Proterozoic and Archaean crust, which suggests that the Grenville crust was derived at least in part form the mantle;  it thus represents new crust that formed about 1.1 to 1.5 billion years ago.   The age of the anorogenic granites is similar, about 1.5 to 1.3 billion years ago, and the distribution of these granites in approximately parallel to the Grenville belt.    These relations suggest that the anorogenic granites may actually be orogenic granites if they were related to arc-type orogenesis forming the Grenville province along the continental margin.   Questions from Dave Stewart and anonymous.

     Jan Tullis next talked on her experimental studies of the dynamic recrystallization of quartz and feldspar in the development of ductile shear zones in granitic rocks.   The experimental results show that when it comes to deformation arena,  quartz is a wimp and feldspar is an inflexible bully.    In quartz, dislocations can easily climb whereas in feldspar,  they become tangled and lock.   As a result feldspar cannot decide what to do and it rigidly holds its ground, only to get slowly pulverized from the margin in.   Because glide planes easily form in quartz,  it goes with the flow, easily changing from one position to another.   In the end, faults are preserved in feldspar samples, but quartz is adept at hiding them by recrystallization.   One study with two compositions  of plagioclase also demonstrated that deformation can induce recrystallization, apparently by facilitating diffusion. Questions from Gene Robertson, Ben Burden, E-an Zen, and Gene Robertson again.

     The final talk was by Ted Bence on the genesis of carbonate hosted Zn Pb deposits of the Reocin ore body in northern Spain.    The ore body is stratabound and occurs only in association with dolomite reefs;  it is characterized by abundant sector-zoned sphalerite and skeletal galena; these textures suggest that the mineral grew rapidly from solution.   Bence also presented Pb and S isotopic data.    The data suggested that ore formation was both syngenetic and epigenetic, and that some of the fluids may be related to older Triassic evaporite deposits.   Questions from Dan Milton, E-an Zen, Jerome Machamer, and Bill Leeman.

     The meeting was adjourned at 9:40 PM.   82 members in attendance.

     Respectfully submitted

     R. Brooks Hanson

 

GEOLOGICAL SOCIETY OF WASHINGTON

Minutes of the 1187th Meeting, 

22 March 1989

     President Hanshaw called the meeting to order at 8:07 PM.   The Minutes of the 1186th meeting were read and approved.   Guests Robert Fraser, Mashashi Swui, Boris Benke, Mike Lias, Will White, and Greg Boyce were introduced, as were new members James Gleason, Julia Triplehorn, and David J. Harding.

     There will be a spring GSW field trip to the Triassic Culpepper Basin led by Joe Smoot on May 6.   Because of less than enthusiastic turnouts on field trips in the past,  the trip will be not run unless at least 10 people sign up. Also GSW contributions to the IGC are now greater than $600.

     Dave Spidel presented an informal communication on geodemographics based on the North American Survey of Geoscientists.   There were several interesting statistics:   There are 17000 geofaculty at 4 year colleges, mostly in the 40 to 49 year old age group.   There are more women,  although still not many,  in the younger age groups, hydrology, atmospheric sciences, and oceanography. The number of undergraduate geoscience majors declined sharply in 1983, but graduate enrollment has suffered less, especially in geophysics.   Recruitment of minorities is pitiful:   there were 2 Hispanic female Ph.D.s in the study period.     Comments from Bruce Hanshaw.

     The first talk was by Jane Hammarstrom on the origin of Emeralds of Pakistan.   Pakistan emeralds occur in several mining districts, most of which are in melange units along the main mantle thrust of the Indo suture zone. Most emeralds have been found in quartz veinlets in talc.   Hammarstrom presented geochemical evidence that showed that the Pakistan emeralds are low in Cr and that many are zoned,  typically with a dark Cr-rich rim.   In general, because Be and Cr do not behave similarly geochemically,  a unique geologic setting is required for formation of emeralds.   Most emeralds are associated with suture zones, as in Pakistan, or with granitic intrusions in greenstone belts.   Questions from Downing, Pete Toulmin, and E-an Zen.

     The second talk was by Hans Seuss on Vertebrate fossils from Nova Scotia and Late Triassic mass extinctions.   Nearly as interesting as their sudden extinction,  is the sudden dominance of dinosaurs in the geologic record.   There were 1, possibly 2 periods of late Triassic extinctions.   Lizards with "cute little overbites"--saber-toothed Crocodiles, and other mammal like reptiles are preserved in Triassic "heavenly hash" facies in the Bay of Fundy, where most fossils have been found.   Footprints are also preserved in these playa lake deposits.   There was a very sudden transition at the Triassic-Jurassic boundary, which led to the ascension of the dinosaurs, and a large, but poorly dated impact site is nearby in Quebec.   A search for diagnostic impact material at the boundary has not produced positive evidence for such a holy hand grenade, however.   Question from Bill Leeman.

     Bill Leeman presented the final talk on the implications of basalt-rhyolite volcanism on the Snake River Plain for crust-mantle evolution or how much melt can a mafic magma make.   Rhyolitic volcanism on the SRP can be subdivided into about 8 eruptive centers that young to the NE toward Yellowstone. Each center was active for about 2 to 4 million years.   The characteristic pattern of activity at each center is rhyolitic volcanism followed by basaltic volcanism.    The felsic magmatism is characterized by huge rhyodacite flows, and relatively small amounts of ash flow tuffs.   These magmas had unusually high temperatures, near 1000ēC, and were relatively dry, thus one possibility is that they could have been produced by fractional crystallization of basalt.  However, the composition of the rhyolites indicates that 96% fractional crystallization from a basaltic source would be required, and thus the required volume of basalt would be excessive.   Therefore, partial melting of water-poor lower crust may be more likely;  if so mafic magmas can make much melt.   Questions from Paul Lowman, Brooks Hanson, and E-an Zen.

     President Hanshaw adjourned the meeting at 9:57 PM.   85 members in attendance.

     Respectfully submitted

     R. Brooks Hanson

 

MINUTES OF THE GEOLOGICAL SOCIETY OF WASHINGTON

1188th Meeting, 12 April 1989

     President Hanshaw called the meeting to order at 8:05 PM.   Guests included Kyler Nearshaw, Doug Neabert, and Betsy Peebles.   There were no announcements.

     Paul Lowman presented the first of two informal communications on Radar imaging of the Sudbury Basin in Canada.   This oblate basin in an impact crater found by Bob Dietz in 1964.   The question is why does it have an oblate shape? Is it a glancing impact, or is it an enormous strain ellipse recording the Precambrian deformation events that clearly affected nearby rocks?  The radar images reveal numerous lineaments that are not deformed, a conclusion that provoked an audible groan of disappointment from a few structural geologists; therefore the crater area appears to have been unaffected by the deformation events.   Comparison with impacts on the moon and mars indicate that oblate craters can form, albeit rarely.   Questions from Tom Wright

     Paul Krantz next presented a premature informal communication on Maryland Dinosaur fossil localities.    The communication will mature into a talk on the 17th of May at the meeting of the Paleonotological Society of Washington held at the Smithsonian.   It appears that Maryland dinosaurs,  including Lower Cretaceous astrodons and Psaurapods,  are again nearing extinction.   The fossil sites are scheduled to be reclaimed and there are only 5 to 6 months left to excavate;  therefore volunteers wanting an action packed day on a dinosaur dig are needed to help save Maryland Dinosaurs from the impending impact of development.

     Ray Price, visiting from Canada, presented the first talk on Metamorphic Core Complexes of the first and second kinds in the Cordillera, with specific reference to the Canadian Cordillera.    Geophysical data indicated an anomalous region in the vicinity of numerous core complexes in the southern Canadian Cordillera.   This region experienced Mesozoic crustal shortening and terrane accretion followed more recently by large scale strike slip faulting. Price suggested that given this two-fold tectonic history,  there might be two different types of core complexes.   The first is associated with the crustal thickening and represents cores of North American basement exposed beneath the allochthonous terranes.   The second type of complex is exposed to the west of the main overthrust belt and reflects uplift and extension associated with two continental scale transform fault--that is, an enormous pull apart structure. Questions from E-an Zen, Robin Brett, and Tom Wright.

     Janet Herman next described geochemical process in groundwater mixing zones in coastal carbonate aquifers.    Herman has developed a computer model of the various factors controlling the direction of the various reactions and applied it to ground water mixing zones in such dreadful places as the Yukutan and Mallorca,  Spain.   In these environments, mixing of marine and groundwater can lead to complex solution/precipitation fronts and the development of swiss cheese rocks and complex coastlines, dolomitization, and calcite or aragonite precipitation.    One interesting result is that uniformitarianism is not applicable in Mallorca:   pumping of fresh water has resulted in a landward dipping aquifer and thus the current mixing environment is significantly modified from that of the past. Questions from George Helz and one other.

     The final talk was by Peter Zeitler who was supposed to talk on the thermal history of an unusual intracratonic thrust fault in central Australia, but mostly discussed exciting new work on possibilities of Ar/Ar dating of K feldspars.    Structural and geophysical data from central Australia indicate the presence of a crustal scale thrust faults of Late Proterozoic age; one suggestion for the origin of such features is runaway uplift and whole crustal failure, real "down under" tectonics.   This problem provided a springboard for investigating K feldspar dating systematics.  At first glance the Ar dates on feldspars appeared to provide little information on dates of cooling events. However, an Arhennius plot and TEM data suggested that the K feldspars may provide multiple cooling dates because perthitic exsolution has resulted in a variety of effective grain sizes--and thus closure temperatures--in single feldspar grains.    Questions from George Helz, Gordon Nord, and anonymous.

     President Hanshaw adjourned the meeting at 9:59 PM after a late introduction of new members Marshall Reed, Don Triplehorn, Abigail Brett, and Martha Gerdes, who were elected during the meeting; 69 members and guests in attendance.

     Respectfully submitted,

     R. Brooks Hanson

 

GEOLOGICAL SOCIETY OF WASHINGTON,

Minutes of the 1189th meeting,

26 April 1989

     President Hanshaw called the meeting to order at 8:10 PM;  the minutes were approved as read.    New members Mark McBride and Elizabeth Peebles were introduced as were guests Murray Gregory and Norman Churches.

     Liz Cron distributed application forms and information on GSW dues in the hopes that the subject of the all of the talks of this meeting-~RADON--might attract potential new GSW members.   She also encouraged the 68 members present to distribute these sheets after the meeting to unfortunate colleagues who are not yet members.   Despite the apparent formality of the official applications, she promised to still accept applications written on brown paper towels from the third floor mens room.   This of course raises the question of why such towels are distinctive to Liz, or for that matter, whether the USGS keeps track of such things.

     Joe Smoot next stated that 5 more participants were needed for the field trip to the Triassic Culpepper Basin.   President Hanshaw tried desperately to sabotage this plea by first saying that the May 6 field trip would be on May 5, and then later changing the date to May 7.   I presume Penny apologizes if anyone spent a Friday or Sunday loitering around the USGS parking lot.

     President Hanshaw mentioned that 3000 people were registered for IGC at the time,  rumors that the Washington weather would be relatively cool for the meeting.   This can explain the subsequent surge in registrations.

     There were no informal communications.   All three talks,  as mentioned earlier, were centered around the subject of RADON.

     Michael Boyd presented the first talk, entitled Radon:  measurement, risk, and national policy.   Boyd presented an overview of the Radon problem,  its historical recognition, and studies that have been done to assess relative risk.   Early recognition that there may be a significant radon risk occurred when a worker living in the Redding Prong set off detectors when he showed up to work at a not-yet-operative power plant.   Boyd explained that as a result of the new indoor radon abatement act, our national goal is to have air as clean inside buildings as outside,  that is,  at least with respect to RADON.  One difficulty in assessing and mitigating the effects of radon, however,  is smoking, which is a particular confounding problem and raises the radon risk significantly.   Questions form Frank Ross twice, E-an Zen, Liz Cron, Ray Rye, and Roz Helz.

     Jim Otten next talked on Mapping radon potential in rocks and soils and presented specific examples of the potential in Montgomery and Fairfax Counties.   The latest estimate is that 8 to 12% of U.S. homes have radon concentrations greater than 4 picocuries per liter; homes in northern states are generally more susceptible because they tend to be built with basements.   Important aspects controlling soil potential are soil moisture and permeability and bedrock geology.   During the presentation of the county maps,  the audience became particularly restless, perhaps because several members live in the western parts of the counties, where the radon potential is highest.   Questions from George Helz, anonymous, Frank Ross, Tom Simkin, E-an Zen, Gene Robertson, John Keith.

     Linda Gunderson rounded out the radiogenic evening with a talk on Radon in shear zones.   Her studies showed that deformation has a strong effect on Radon distribution, perhaps because U has been deposited in the shear zones during or after deformation; Furthermore, deformation facilitates emanation of radon. Shear zones in the Appalachians typically have high Radon concentrations. Questions from Bill Bentson, Gene Robertson, Charles Druitt, and three questions from George Helz.

     President Hanshaw adjourned the meeting at 9:40 PM.

     Respectfully submitted,

     R. Brooks Hanson

 

Geological Society of Washington

Minutes of the 1190th meeting,

October 11, 1989

     President Hanshaw called the meeting to order at 8:08 PM. Perhaps because few attendees of the 1190th meeting remembered details of the 1189th meeting, the Minutes of the 1189th meeting were approved as read.   New members Michalann Harthill, Jeffrey G. Ryan, Whitman Cross II, Daniel Sullivan, Andrew H. MacDonald, and John Lennon and guests Bob Seal, Peter Hane, Gray Bebout, Candy Balachanan, John Rawly, Gerald Martin, Henry Brunz, Margaret Chancy, Phil Chaney, Cheryl Pattins, Mark Everett plus 2 others were introduced.   Mark McBride, who was introduced as a new member in absentia in the 1189th meeting,  introduced himself in person and was welcomed,  and President Hanshaw,  in response to the openness of the many guests, asked if there were any members in attendance who had not come in awhile and dared to admit it.   None did. President Hanshaw announced the deaths of 5 members: K. Y. Lee, Edmond B.  Eckle, Henry Bell, Ted Flinn, and King Hubbert, and a moment of silence was observed.

     Bill Leo announced that the Fall field trip would be to Rock Creek Park and was limited to about 20 people because of narrow paths and other unidentified hazards.   Jim O'Conner will be leading the trip and should be contacted for information.

     Gerry Barton from the Potomac Geophysical Society next announced that their meetings are on the third Thursday of each month at the Ft. Myer Officer Club and that GSW members are welcome. Unlike the strict format of the GSW meetings, people can really relax at the Potomac Geophysical Society. As a further incentive for coming, Gerry mentioned that their last talk was on Hurricane Surge Modeling, with an example for Charleston, S.C.;  this talk was presented the night before Hugo hit;  their next talk was on Seismic Wave attenuation in New Madrid and Gerry hinted that the society might be becoming a disaster predictor. Well Loma Prieta is not too close to New Madrid, but perhaps its good enough for the Potomac Geophysical Society.   Since it now looks like they are sort of 2 for 2, we should find out if the November talk is on asteroid impacts and perhaps plan to attend.

     Michael Harthill announced that the Society of Women Geochemists is looking for speakers and encouraged applications.

Penny Hanshaw finally got to say a few words about her favorite topic this year, the IGC.   The Congress was attended by 6000 attendees from 103 Countries and finished in the Black.   She also mentioned that GSW dues time is approaching, perhaps in the hope that if all of the guests at tonights meeting would join, GSW might also finish in the black.   She also mentioned that most of her fan mail is from AAPG, of which GSW is an affiliate, and as a result, members can obtain insurance through AAPG, which sounds safer than through the Potomac Geophysical Society.   Finally she announced that Liz Cron has nothing to say.

     President Hanshaw summarized the discussion of the council meeting as basically "expenses are rising and revenues are not," and we now have a new slate of officers.

     Bob Luce presented an informal communication on New ideas on the Murphy Syncline, North Carolina.   The rocks in the syncline have been mapped as non-volcanic sedimentary rocks, but on closer glance appear to be mafic tuffs associated with sulfide deposits.    The association of tuffs with chert, and carbonate units may imply that deposition occurred near a deep marine volcanic center.   A belated question from Doug Rankin, and Liz Cron still had nothing to say.

     Bilal Haq presented a condensed version of his talk on Sequence stratigraphy and sea level change.   Haq showed how depositional patterns in seismic sections on passive continental margins can be correlated to identify global eustatic sea level changes.   The development of seismic stratigraphy has allowed resolution of various stratigraphic problems and has helped in the identification of packages of rocks likely to be enriched in petroleum.   Questions from Penny Hanshaw, Bill Howser, and Tom Wright.

     Nell Irvine next talked on A Global Framework for mantle convection.   He proposed that the distribution of major hotspots, which are oriented 90 degrees apart, and corresponding opposite poles reflect the fundamental pattern of mantle convection. The key upwelling centers are beneath Hawaii and Iceland, and the Belamy islands in Antarctica and the Okavango Volcanic Fields in Africa whereas the downwelling centers are near Peru and Vietnam.   A variety of geophysical patterns including geomagnetic anomalies, apparent topography on the core mantle boundary,  seismic travel times in the mantle, and crustal tectonic patterns appear to fit this orthogonal pattern.   Questions from Bill Hallager, Gene Robertson, Dan Milton, Bruce Anjey, E-an Zen, Sorena Sorensen, and Brooks Hanson.

     The final presentation was a movie entitled The Earth has a History; and E-an Zen first explained the history of this movie.  It started when Pete Palmer had a debate with Creationists in Boulder Colorado and challenged them to a field trip to the surrounding area.   The focus of the movie is on demonstrating from field evidence only that deposition and tilting of the sedimentary rocks in the Boulder Colorado area required many millions of years not the mere few thousand years required by Creation Science.   No questions were asked.   President Hanshaw adjourned the meeting at 10:10 PM.   84 members in attendance.

     Respectfully submitted,

     R. Brooks Hanson

 

GEOLOGICAL SOCIETY OF WASHINGTON

Minutes of the 1191st Meeting, 25 October 1989

     President Hanshaw called the meeting to order at 8:08 PM; The minutes of the 1190th meeting were read and approved without revision.

     New members Kevin Burke, William F. Sledjeski, Henry Burns, K. Balachanran, Gerald Barton, Chery Petrina, and Anne Marie Reidy were introduced as were guests Chuck McMorrow, Barbara Frank, Catherin Geoberneck, Keith McGlouflin, who announced that he liked to show up for at least 1 meeting in 2 years, Mark Regan, D. T. O'cuie, and Brian Rosin.

     President Hanshaw announced that Gene Tolbert had passed away and a moment of silence was observed. President Hanshaw also announced that the nominating committee had, with minimal arm-twisting, nominated a slate of officers for the new GSW year; this list was distributed at the meeting. There was also a second notice of the fall field trip to nearby Rock Creek Park.

     Randy Opdyke of the USGS presented an informal communication updating the Loma Prieta, or informally world series, Earthquake. Randy was "invited" (i.e., coerced) into this presentation only a few hours before the meeting, apparently because AI Michaels, who had provided expert commentary during the earthquake, was not available. This worked out for the best anyway because Randy was able to incorporate data received by FAX that day. The earthquake struck at 5:00 PM on the 17th of October. It was upgraded the day of the meeting to M 7.1 on the basis of new data from 18 international stations.  The initial rupture was at 18 km, an exceptionally deep event for the San Andreas. Three teams of red-faced geologists were sent on the geologic equivalent of a snipe hunt to find a surface break that corresponded to the fault motion; when they could not find any such break, the seismologists brilliantly concluded that slip did not extend to the surface. Much of the damage occurred in areas with extensive liquefaction, as in the Marina district.  Questions from Dan Milton, Sorena Sorensen, E-an Zen and two others.

     The first talk was by Tony Coates on patterns of evolution and ecology off Panama Despite heckling and kibitzing by brand new member Kevin Burke, Tony managed to update us on the progress he an several colleagues are making on measuring evolutionary processes in Panama. Species on the Atlantic and Pacific coasts of Panama became isolated only about three million years ago, when the isthmus formed. Thus the sections on the opposing coasts can be used to study the evolutionary response of populations to geographic isolation. However, this requires careful stratigraphic and paleontologic correlations in rocks deposited in different tectonic environments. The Caribbean section is evidently much thinner than that on the Pacific coast. Initial data suggest that corals are now very different on the two coasts whereas bryozoans are rather similar. Other data suggest that the molecular clock may be ticking at different rates in 2 slightly different snail species. Questions from Rob Ross, E-an Zen and Kevin Burke, who wanted to know the relation between plate tectonics and opossum wandering habits.

     Claire Parkinson next talked on measuring changes in global sea ice; such measurements may provide a first indication of the effects of global greenhouse-related warming in that modeling studies suggest that polar regions may be most affected. Sea ice covers approximately 24 million square kilometers of the Northern Hemisphere, and is important for global albedo, oceanic heat flow, and the formation of cold bottom waters, so its responsible for important climatic processes. Sea ice emits microwave radiation more so than open, ice-free water, and thus satellite measurements can provide an estimate of the extent of ice cover. Although southern ice cover decreased in the mid to late 1970s, prompting initial warnings of impending doom to penguins and other coastal inhabitants, no effect was seen for the northern hemisphere. Furthermore, ice cover has expanded in the1980s. Questions from Hendrick Van Oss, Fred Simon, Geramy Barton, Rob Ross, and E-an Zen.

     The final talk was by Nicholas Woodward on non-eularian deformation with examples from the Appalachians. Woodward described several field studies to address the origin and evolution of thrust faults, with specific reference to the fault tip hypothesis, which is a eularian description of how chevron folds evolve systematically into thrust faults. Woodward showed that the fault tip hypothesis will not work for thrust faults in the Pine Mountain fault system of Tennessee. Instead these thrust faults are not what they appear to be, that is their development is shall we say Woodwardian, not eularian. The development of the faults appear to have involved cycles of thickening and thinning, that is extension, of the fault zone. This woodwardian concept of misperception provides a nice theory linking key aspects of this evenings talks--earthquake ruptures that turned geologists into snipe hunters by not reaching the surface, snails with everready versus ran-down Ray-O-Vac batteries charging their DNA clocks, and sea ice that was only disappearing for awhile.  Questions from Gene Robertson and anonymous.

     President Hanshaw adjourned the meeting with its 68 attendees at 10:15 PM.

     Respectfully submitted,

     R. Brooks Hanson

 

Geological Society of Washington

Minutes of the 1192 meeting, 15 November 1989

     President Hanshaw called the meeting to order at 8:03 PM The minutes were approved as read yet again.

     President Hanshaw announced that Ellis Yochelson wanted to announce that there is a Geologic Mapping exhibit at the Library of Congress until January 7, 1990. The recent GSW field trip to rock Creek Park led by Jim O'Conner was a glorious success; Jim managed not to lose 20 geologists in the wilds of Rock Creek.

     E-an Zen next announced that the National Academy of Sciences has issued a report entitled "Being a Scientist," which includes comments on plagiarism, fraud, and general unethical behavior, that is, ways not to be a scientist.

     Sparked by E-an's announcement Penny Hanshaw mentioned that it is possible to turn even inner city kids to geology. This conclusion was reached after enlightening young inner-city St Louis youths to the excitement of geology during a GSA sponsored field trip.  Despite preconceived impressions, for example one youth had proclaimed that "Field Geology is nothing a lady should be doing," the trip was a smashing success.

     President Hanshaw summarized the report of the financial committee as "You too can fight a dues increase," although hints on how you might fight it were put off to later meetings. If the spirit is there substance will follow.

Dennis Krohn presented an informal communication entitled New Ammonia Occurrences and Army Tanks.  Krohn has been mapping ammonium feldspars by satellite. The petrologists in the audience were somewhat disappointed to learn that this is not a new rapid point counting method, but a way to detect large ammonium deposits associated with felsic tuffs by remote sensing. Krohn was able to find a huge ammonium deposit 20 miles North of Tonapah in a 29-million-year-old tuff only to have the access closed off by the U.S Army. The unanswered question is why is the Army so interested in ammonium?  Questions were answered from Hendrick Van Oss twice, Bevin French, Dan Milton, Pete Toulmin, and Fred Simon.

     Mike Ryan presented the first talk on the physics of the Icelandic magma system and spreading process. Ryan described how magma wends its way from the mantle to the surface in Iceland on the basis of geophysical data, finite-element modeling and studies of rift-zone volcanoes. Magma is apparently stored in magma chambers at 2 to 4 km depth, and several chambers are oriented in a left stepping en echelon pattern. The modeling suggests that there is a nearest neighbor effect in that activity at one center can influence stresses and activity at neighboring centers. Beneath Iceland, a signature of the mid-ocean ridge spreading system is not evident in the 3D structure in the mantle below about 175 km. Questions form Gene Robertson, Brooks Hanson, Sorena Sorensen, Kevin Burke, and E-an Zen.

     James Galvin next talked on wind skimming as a mechanism of Ir enrichment. Galvin presented a hypothesis to account for enrichment of Ir observed in certain layers, most notably, at the Cretaceous-Tertiary boundary. His argument can be illustrated by the common example of a group of people wind surfing for the very first time; think of the surfers as little particles of extraterrestrial dust containing Ir supported by the sail boards representing the surface scum. A basic principal of wind surfing is that its impossible to sail upwind the first time out, or sometimes even after that. With even a gentle wind, therefore, all of the It-rich surfers will soon be jammed up and grounded, with the scummy boards, along a windward shore. If deposition occurs, the near-shore deposit should thus contain more than the average number of surfers and thus an Ir spike. Galvin showed in a more simple experiment that small particles can be supported on surface films and suggested that if this occurs for a reasonable length of time, some concentration is possible.  Selective preservation associated with the continual process, might account for apparent enrichments. Questions from Mary Hill French, Hendrick Van Oss, Leslie Rucker, Jeff Grossman, Dan Milton, Bevin French, and Charles Basaro.

     The final talk was by Jim Beard on experimental evidence for the generation of tonalitic melts in island arcs. Jim showed that amphibolites should not drink excessively before driving up the path of arc magmatism. Sloshed amphibolites replete and saturated with fluids at the lower crustal bar produce peraluminous melts unlike most arc tonalites. Their erratic and atypical behavior includes retention of amphibole and loss of plagioclase upon heating. In contrast, amphibolites that have imbibed only small amounts of water-rich fluids, can easily continue to evolve to arc tonalites while leaving a characteristic granulitic residuum. Questions from Dan Milton, Kevin Burke, and E-an Zen.

     The meeting was adjourned at 10:05 PM. 65 members and quests in attendance.

     Respectfully submitted,

     R. Brooks Hanson

 

Geological Society of Washington

1193rd Meeting, 13 December 1989

     President Hanshaw called the meeting to order at 8:06 and, no doubt because of excessive enthusiasm and impatience, flagrantly violated Society protocol by immediately beginning her Presidential talk on Changing America and who will do Science. She preempted any introduction, reading of the meetings, announcements, informal communications, or introductions of guests and new members. She introduced herself by saying merely that if anyone had not been to a meeting and did not recognize her (or realize that this was the annual meeting) then tough! Despite objections all year from past Presidents on improper procedures, the audience, which was stacked with GSW all-time all-timers, was caught off guard this time, and not a single voice was raised in protest, so President Hanshaw continued without breaking stride.

     In her address, President Hanshaw's summarized the findings and recommendations of a Congressional-delegated task force on women, minorities, and handicapped in science and technology. Formation of this study group was prompted by concern for the future scientific vitality of the country--a shortfall of 765,000 scientists and engineers is predicted by the next century--and a recognition that we will have to look to minorities and women to carry this load. Members of the task force were largely women and minorities from 15 federal agencies and several universities, corporations, and nonprofit organizations. The task is immediate because changes in precollege education today, where we rank a disappointing 9th in the work in physics and 11th in chemistry may not have an impact in the job market until some 20 years down the road.

     Sparing the audience the customary field shots of public hearings in exotic places like downtown Washington, DC, President Hanshaw instead left some other depressing images of the scale of the problem: Colleges are now becoming more and more dependent on foreign graduate students, who make up nearly 40% of the science graduate students in some universities. U.S students show a disproportionate decline in scientific interest. In 1988 only 48 Ph.D's in science were awarded to Blacks, even though the 25 largest school districts in the United States are 45% Black. Needed in many communities are positive role models from these communities; one way to help may be to involve the entertainment industry, which could promote scientists by such shows as "LA Engineers:" an exciting look at the tumultuous lives of scientists and engineers, when they have time between NSF proposals.  After all, look what LA Law has done for lawyers, which we most certainly don't need more of. Other recommendations were focused on both short and long term improvements in precollege education, particularly in math, of particularly Blacks, American Indians, and Hispanic students.

     President Hanshaw closed with a final uplifting demographic observation, namely that because of the aging of the population, by 2050 there will be one person on social security for every one person working. This sparked groans from particularly the younger members of the audience, and when President Hanshaw prematurely adjourned the meeting at 9:05, a rush for beer. It was a premature adjournment because Sorena Sorensen gently but firmly reminded President Hanshaw that other meeting activities needed to be taken care of.  The minutes of the 1192nd meeting were finally read after a 15 minute break and approved. 60 members and unidentified quests in attendance.

     Respectfully submitted,

     R. Brooks Hanson

 

Geological Society of Washington

Minutes of the 97th Annual Meeting

13 December, 1989

     President Hanshaw called the meeting to order at 9:15 PM. The minutes of the 96th annual meeting were read and approved by Bruce Wardlaw first and then the rest of the society. The series of reports by officers of the council followed. Highlights included the meeting's secretary, that's me, insertion his foot into his mouth after boasting that there were no corrections to his minutes all year but then proceeded to miss one death in the society in his final report. The obvious conclusion is that no one listens to the minutes aside from Bruce Wardlaw, who tried to approve the minutes, and Liz Cron, who interrupted Bruce to offer the correction.

     Treasurer, Dick Tollo noted that the society survived barely in 1989, but that 1990 foreshadowed a possible dangerous situation because projected income lagged behind expenses by about $600. Bruce Wardlaw again over-eagerly moved to accept the report; this time he was rudely cut off by President Hanshaw because approval of the Treasurer's report must follow the report of the Auditing committee. Bruce Lipin then reported that aside from a missing 40 cents, Dick Tollo's mac managed to balance the books, and Bruce was finally satiated. Liz Cron noted that the society welcomed 48 new members for a grand total of 861. Bruce moved to approve. Three Science fairs were judged. Bruce approved. Roz Helz won the Great Dane award for her informal communication on the Kilauea Lava lake; and Anne Wiley received the Bradley Award for her report on Asbestos and the Law. Penny did not ask for approval.

     All of this was, of course, build-up for the highlight of the annual meeting-- presentation of the coveted Sleeping Bear award! But wait! The Sleeping Bear committee was absent from the meeting, so there was no presentation. To save face President Hanshaw suggested that Doug Rumble certainly deserved to hold onto it for another year, but might we guess who will get the appropriately named Sleeping Bear award this year?

     Fred Simon presented the report of the Financial Planning Committee, who's main achievement was creation of the Endowment Fund, which was replete with $9400 in donations and pledges at the time of the meeting. Finally, the officers for the 98th year of the society were approved, first by Sorena Sorensen, as Bruce had apparently dozed off by this point. As a final thought, I have to wonder how we will make it through this meeting now that Bruce is busily taking notes and must really pay attention to the council reports.