STRUCTURAL GEOLOGY and
TECTONICS DIVISION
Newsletter
Volume 15, Number 1 March, 1996
CHAIRPERSON'S MESSAGE
Division activities at the annual meeting in New Orleans went smoothly,
as usual. As
co-convener of our division symposium "Products and Processes
of Continental Extension"
which was held jointly with the Geophysics Division, I want to thank
my co-convener, John
Geissman, and especially all of the speakers who made the symposium
a success (please also
see the symposium report later in this newsletter!). Bruno Vendeville,
Martha Withjack,
and Gloria Eisenstadt taught the division-sponsored short course this
year, "Introduction to
Experimental Modeling of Tectonic Processes," for which I heard
nothing but praise. Well
done, and thanks!
I would like to personally congratulate our 1995 division award winners.
Student
research awards went to Kurt Constenius (University of Arizona) and
Tim Paulsen
(University of Illinois). Their research proposals were selected from
a pool of many very fine
proposals; the choice was so difficult that the management board had
to revote to select the two
best! Because we have sufficient funds and continue to receive so many
high quality student
research grant proposals, we plan to continue making two student research
awards awards in
the future.
The Career Contribution Award went to B. Clark Burchfiel, who was both
nominated and cited at the award ceremony by his close friend and long-time
research
collaborator, Greg Davis. Those present at the awards ceremony will
not soon forget Greg's
citation -- especially all those old slides of Clark with muttonchop
sideburns! (There is
absolutely no truth to the rumor that, while doing fieldwork in southern
Nevada in the early
1970's, Clark moonlighted in Las Vegas as an Elvis impersonator).
No SG&T Best Paper Award was made in 1995 for lack of nominations.
The dearth of
nominations continued this year; I had only received 2 new nominations
as of the deadline on
February 1, 1996. This unfortunate situation stimulated considerable
discussion among the
division management board and Best Paper Award Committee chair Bill
Dunne. At the
management board meeting in New Orleans, we revised Best Paper Committee
procedures to
permit committee members to add nominations to those from the membership
at large, but none
of us particularly likes this solution. Therefore -- we have extended
the Best Paper
Award nomination deadline this year to April 12 to give you, the division
members,
additional time for your voices to be heard. Please take the time to
cite that really great paper
that you read in the last year of so, and mail (or e-mail) in a nomination
to me (John Bartley,
Department of Geology and Geophysics, University of Utah, Salt Lake
City, UT 84112;
jbartley@mines.utah.edu) or to Bill Dunne (Department of Geological
Sciences, University of
Tennessee, Knoxville, TN 37996-1410; bill@yoda.gg.utk.edu). Continuation
of the award
depends on your participation!
The Management Board also discussed a few other concerns. The number
of structure-
tectonics abstracts submitted for the New Orleans meeting was down
significantly from the two
previous years, but overall submissions and attendance also were down,
presumably because
of factors relating to geographic location of the meeting. However,
division membership also
is dwindling such that, although we still are the largest division
of GSA, what used to be a
large margin now is much smaller. Bigger is not necessarily better,
but it is hard not to worry
about the meaning of shrinking membeship! The Board will continue to
serve the
memberships' wishes and interests as well as it can, but if there is
something that you wish that
we were doing, please let a division officer know.
In response to suggestions from past Short Course Committee chair Rick
Allmendinger, the board also discussed revising the charge of the Short
Course Committee
to give it more autonomy than it has under current division bylaws.
The selection of the short
course has been an annual scramble, which we anticipate that the proposed
bylaw revisions
will mitigate considerably. Please look for, and vote on, these revisions
when you receive
your annual division ballot in the September "Newsletter".
Division treasurer Art Goldstein told the board that we have accumulated
a modest
financial surplus, and asked the board what we wanted to do with it.
Many ideas were floated
(everyone likes to spend money!), but two were particularly popular.
First, at spring section
meetings we want to restart the once-popular SG&T-sponsored evening
poster-session/keg
parties. All of us could remember what a good time we used to have
at these, and we all were
enthused by the idea of having them again.
I am able to pass this information on to you owing to the stalwart
efforts of Greg
Davis and Scott Paterson as "Newsletter" co-editors. Alas,
Scott is taking a sabbatical next
year from his duties at USC and at the same time stepping down as SG&T
"Newsletter" co-
editor. Scott and Greg have done a terrific job for which they have
my enthusiastic personal
thanks. Greg has agreed to continue as editor, and the Management Board
is committed to
providing Greg whatever help he needs to keep up the good work.
Finally, we are considering marking the year 2000 with a major division-sponsored
conference to be held separately from the annual GSA section and national
meetings. Our
intention would be to examine, discuss, and promote a prospective scientific
agenda for
structural geology and tectonics for the 21st century. This plan is
in its earliest "brainstorming"
stages; if you have a good idea about what we should do, when, or how
-- or about how we
should go about deciding what to do! -- please pass it on to a Management
Board member.
John Bartley, Chairperson; Dept.of Geology & Geophysics, Univ.
Utah 84112
phone (801) 581-6553; fax (801) 581-7065; email: jmbartle@cc.utah.edu
MINUTES, SG&T DIVISION MANAGEMENT BOARD MEETING
November 7, 1995 - New Orleans, LA
ATTENDEES:
Ed Beutner (Chair), John Bartley (Vice Chair), Terry Pavlis (Second
Vice Chair), Art
Goldstein (Secretary-Treasurer), Rick Groshong, Dave Dunn, Sharon Mosher,
George Davis,
Steve Reynolds, Greg Davis, Bob Hatcher, Don Davidson (GSA Executive
Director)
1. RESULTS OF ELECTION
Vicki Hansen (S.M.U.) has been elected Second Vice Chair for 1996.
John Bartley
assumes the duties as Division Chair and Terry Pavlis assumes the duties
of Vice Chair.
2. REPORT OF SECRETARY-TREASURER
Division income exceeds expenses at a rate of between $2,500 and $3,500
per year. At
the end of 1995, we will have a surplus of approximately $10,000. Discussion
of what to use
these funds for resulted in a decision to 1) reinstate divisional receptions/poster
sessions at
sectional meetings with refreshments paid for with divisional funds;
2) purchase a computer to
be used for a divisional WWW Home Page; and 3) continue to accumulate
excess funds with
the goal of using these funds for some "spectacular" divisional
event in the year 2000.
Divisional membership stands at 1,360, compared with 1,535 in 1994
and 1,692 in
1993.
3. DISCUSSION OF DIVISIONAL NEWSLETTER
After an inquiry from the Board, Greg Davis reported that he and Co-Editor
Scott
Paterson do not believe that it is desireable at this time to replace
the hard copy "Newsletter"
with a version delivered electronically or with a substitute "publication"
in a home-page format.
It is their opinion that the "Newsletter" is a tangible benefit
to Division membership and one
that goes to all members; not all members currently have access to
electronic mail although that
situation is evolving rapidly. Looking for information in a home-page
format is a proactive
task, whereas the hard copy "Newsletter" arrives by mail
and can be looked and read (or not
read) at the convenience of the recipient. Greg and Scott both agree
that some kinds of
information could easily be transmitted to the membership electronically
(see 4. below).
Opinions from the membership regarding a hard copy vs. electronically-transmitted
"Newsletter" are welcomed by the Editor and will be shared
with the membership. [Addendum:
Scott will soon be undertaking a year-long sabbatical leave and he
has resigned from his Co-
Editor's position following the March, 1996, issue. Comments should
therefore be sent to
Greg and/or John Bartley, the current Chairperson.]
Greg and Scott 's past efforts in editing the "Newsletter"
were highly and unanimously
praised by the Board.
4. DIVISIONAL WWW HOME PAGE
A decision was made to institute a divisional website with links through
the GSA home
page. John Bartley volunteered to initiate this project if the Division
could provide him with a
computer dedicated to this task. Submission forms for Career Contribution
and Best Paper
awards will be located here and will also be mailed on paper with the
"Newsletter". Back
copies of the "Newsletter" could be transmitted electronically.
Other ideas about the content of
this website should be directed to John.
5. DISCUSSION OF BEST PAPER AWARD COMMITTEE PROCEDURES
Steve Reynolds and Ed Beutner reported that the current system of nominations
for
"Best Paper" is not working. An insufficient number of nominations
from division members
prevented us from giving this award in 1995. After lengthy discussion,
the Management
Board decided that the future role of the committee and nomination
procedures would be
changed; see statement at the end of these minutes regarding changes
mandated by the Board
pending additional input from the membership.
6. SHORT COURSE - SYMPOSIUM COMMITTEE PROCEDURE
A change in by-laws, on which you are asked to vote,was discussed.
7. DIVISION SHORT COURSE FOR 1996 NATIONAL MEETING
John Bartley reported that the 1996 short course will be "Tectonic
Geomorphology"
and that he is actively seeking appropriate instructors.
8. DIVISIONAL SYMPOSIUM FOR 1996 NATIONAL MEETING
Terry Pavlis reported that the divisional symposium for 1996 will be
"Intracontinental
Orogenesis" and that potential symposium convenors are being contacted.
9. MERGER WITH G.S.A. GEOPHYSICS DIVISION
A proposal has been made that the SG&T Division merge with the
Geophysics
Division. Discussion was postponed pending the results of discussion
by the Geophysics
Management Board.
10. DIVISIONAL REPRESENTATIVE TO G.S.A. EXTERNAL AWARDS COMMITTEE
Art Snoke was nominated for this position.
STRUCTURAL GEOLOGY AND TECTONICS "BEST PAPER
AWARD": ARE WE MOVING IN THE RIGHT DIRECTION?
As reported elsewhere in this "Newsletter", the SG&T
Best Paper Award was not
presented in 1995 because an insufficient number of nominations was
received. Nominations
for this prestigious award come from you, members of the SG&T Division.
Best Paper Award
Committee members have been prevented in the past from making nominations
to avoid the
appearance of impropriety: it would be wrong for committee members
to be voting on their
own nominations. The Best Paper Award Committee recommends a single
paper to the
Management Board which usually accepts this recommendation. As long
as a healthy pool of
nominations flows to the committee, this process works quite well.
However, last year the
division membership collectively failed to submit nominations. Certainly,this
cannot be
because none of us have read really good papers published in the past
7 years. Rather, we all
seem to feel that someone else will do the nominating or we are simply
too busy to write a
paragraph detailing why some publication is deserving of this award.
The Management Board of the division concludes that, because giving
this award is
one of the most important divisional activities, we cannot allow this
situation to continue.
Thus, we have altered the procedures by which nominations are made,
reviewed by the
committee, and winnowed down to a single award-winning paper. In addition
to receiving
nominations from the membership, Best Paper Award Committee members
will also make their
own nominations. They will then pass all nominations to the Division
Management Board and
will recommend what they believe to be the top 3 from this list, including
a justification for
their preferred choices. The ultimate decision will lie with the Management
Board. Two other
changes should further guarantee a healthy pool of nominations. The
Best Paper Award
Committee will be expanded from 3 members to 5 members and nominations
for the award can
be made electronically, through the divisional WWW Home Page after
it is instituted. After
thoughtful review, it was decided that the new procedures could still
provide the impartiality
needed in this process to avoid the appearance of an "old boys
network" in which papers by
friends of committee members were the only ones nominated.
We would like to hear from division members about these changes. Do
they appear to
be the correct thing to do? Do you believe that the process will remain
fair? Do you have other
ideas about how the process could be changed? We encourage you to submit
your reactions to
Management Board members or to the Divisional "Newsletter".
In the meantime, the deadline
for Best Paper nominations has been set back from February 1st to April
5th. Members can
use a nomination form from past "Newsletters" or contact
Greg Davis or me and we will fax
you a copy.
Art Goldstein, Sec'ty; Dept.of Geology, Colgate Univ., Hamilton, NY
13346
phone (315) 824-2207; fax (315) 824-7187; email: agoldstein@center.colgate.edu
NSF NEWS
Due to the federal budget problems, the government shutdowns and the
Washington
snow storms, during which we were basically locked out, we are at this
writing (January 16)
about a month behind where we should be. One consequence is that this
will be a brief article,
just giving you a status report as of mid-January and a prognosis of
what is likely to happen in
the next couple of months.
Before the shutdown, we had already received approximately 105 Tectonics
Special
Emphasis Area proposals, all submitted for the December 1 deadline.
A few more are expected
to be sent from the central proposal processing unit. Mike Mayhew and
I had read and picked
reviewers for about 30 of them. Mike is now dealing with his new responsibilities
in the
Education and Human Resources Program, but will help with reviewer
assignments as time
allows. The immediate problem for us is to read the remaining proposals
and get the review
requests in the mail in time to have sufficient reviews back from you
for the panel meeting,
scheduled for March 13-15. Whew..
We (NSF and the individual programs) do not yet have an appropriation
for this fiscal
year (which began October 1, 1995), and at this time are operating
on a temporary "continuing
resolution" (which restricts spending to a rate less than the
one during the last fiscal year) and
that is now set to expire on January 26. By the time you read this
article, all this will be ancient
history and we will have a budget for the remainder of the year, but
right now things are pretty
strange. All of us will be glad to get this fiscal year behind us.
In the next issue we intend to
review how the government goes about allocating money for research,
and how NSF goes
about distributing the allocated funds, but in the meanwhile, we've
got some catching up to do!
The following awards were made from the Tectonics Program during the
period July
12, 1995-January 16, 1996. The list is artificially short, as a number
of our recommendations
for awards have languished in NSF's grants offices, due to the restrictions
imposed (in
addition to our customary lack of great speed in such matters). Congratulations
to these (and to
those who will receive awards soon)!
Tom Wright, Program Director, Tectonics Division
fax (703) 306-0382 and 306-0202; email: twright@nsf.gov
* * *
The following awards were made by NSF from the Tectonics Program
for the period July 12, 1995 -January 16, 1996:
P.I. (Institution) Title
Birkeland (Univ. of Colorado, Boulder)
Origin and seismic potential of antislope scarps in mountainous areas
Byrne (Univ. of Connecticut)
Evidence for changing plate motions in the Tertiary Shimanto Belt,
Japan
Connelly (Univ. of Texas, Austin)
Tectonic processes, architecture and isotopic systematics of deep crustal
levels:
Investigation of the Nagssugtoqidian orogen of West Greeland
Dokka (Louisiana State, Baton Rouge)
Mesozoic-Cenozoic tectonic evolution of the Mojave Desert, California
Duebendorfer (Northern Arizona Univ.)
COLLABORATIVE RESEARCH: Tectonic origin and development of an isotopically
mixed crustal boundary zone: The Proterozoic Mojave-Yavapai boundary,
SW U.S.
Fletcher (New Mexico Institute of Mining and Technology)
Crack-anticrack interaction in faulting
Gans (Univ. of California, Santa Barbara)
Petrologic evolution of the northern Eldorado Mountains, southern Nevada
Grunow (Ohio State Univ. Research Foundation)
Timing of West Gondwana assembly and connections to Laurentia: Tests
from the
Amazon craton
Hodges (MIT)
Tectonothermal effects of dynamic compensation in the Himalayas
Hoffman (Harvard Univ.)
Tectonic assembly of Gondwanaland, northern Namibia
Hollister (Princeton Univ.)
Tectonometamorphic evolution of the Great Himalayan Sequence of Bhutan
Holm (Kent State Univ.)
Tectonic setting, depth of emplacement, and unroofing history of the
Middle
Proterozoic Wolf River batholith and associated plutons, Wisconsin
Hudleston (Univ. of Minnesota, Twin Cities)
Shear zone geometry, strain and fabrics in high-grade rocks, northern
Sweden
Hudleston (Univ. of Minnesota, Twin Cities)
Anisotropy and fold development in rocks
Law (Virginia Polytechnic Institute and State Univ.)
Analysis of magma flow and wall-rock deformation in plutons exposed
at different
structural levels in the White-Inyo Range: Implications for emplacement
mechanisms
of granitic plutons
Mayer (Miami Univ.)
COLLABORATIVE RESEARCH: Active tectonics of a young oblique-rifted
continental margin, Loreto area, Baja California Sur, Mexico
Patchett (Univ. of Arizona)
Locating the source of clastics in the Canadian Cordilleran miogeocline:
Nd isotopic
and other approaches to Cordilleran and Innuitian sediments
Samson (Syracuse Univ.)
Tectonic setting and magmatic evolution of eastern Laurentian Late
Paleozoic time:
Constraints from high precision U-Pb dating of Alleghanian granites
Stock (California Institute of Technology)
Tectonic evolution of the Gulf of California and its margins (Partial
funding for a GSA
Penrose Conference)
Teyssier (Univ. of Minnesota, Twin Cities)
Structural and thermochronological constraints on the role of partial
melting during
late orogenic estension
Umhoefer (Northern Arizona Univ.)
RUI: COLLABORATIVE RESEARCH: Active tectonics of a young oblique-rifted
margin, Loreto area, Baja California Sur, Mexico
Wallin (Univ. of Nevada, Las Vegas)
RUI: Origin of the Yreka terrane and the provenance of Sonomia
Wright (Rice Univ.)
Timing of deformation in the Early Mesozoic back-arc basin of the western
U.S.
Cordillera: Luning-Fencemaker fold and thrust belt
EDITOR'S NOTE
NSF proposal submitting policies
In the last issue of the "Newsletter" Scott Paterson and
I solicited comments from
Division members regarding NSF's new policies with respect to proposal
submittal.
Specifically we wondered if the new rule requiring rejected proposals
to be held over a full year
before being resubmitted might not seriously affect young academicians
in their quests for
tenure within the normal six to seven year limit. Only three or four
Division members have
written to us with brief comments on the new NSF policies, and none
of them are among our
junior Division members. The lack of comment either means that the
new policies are deemed
reasonable or, conversely, that individuals may feel at peril if they
take public issue with the
Foundation.
One correspondent believes that the new policies may be creating a
greater diversity in
proposed research areas and that prospective P.I.'s will just develop
multiple proposals for
submission so that they won't miss either of the two proposal deadlines
each year. Another
correspondent suggested the following: if a proposal is turned down
because of some problems
or unresolved issues that can be quickly remedied by a rapid rewrite,
why not give the PI the
option to resubmit the original proposal with an addendum that answers
the problems or issues;
it would be best if the addended proposal could be reconsidered by
the original reviewers and
panel either before or at the time of the next proposal deadline. An
alternative suggestion
would be for NSF to treat proposals from junior faculty members who
are not yet tenured
differently than those from more senior academicians; the junior P.I.'s
would be allowed to
resubmit their failed proposals six months later, rather than waiting
the full year.
It is important to remember that proposal review policies for NSF apply
to the entire
organization. Any changes in proposal treatment would apply to all
of NSF's scientific
divisions, not just Earth Sciences. Perhaps Tom Wright could tell us
in one of his future
"Newsletter" columns how NSF's new rules seem to be affecting
his program and the
structural geologists and tectonicists submitting proposals to it.
Scott Paterson
On a different note, this issue of the "Newsletter" will
be the last for my Co-Editor and
colleague Scott Paterson. Scott will begin a one-year sabbatical leave
in late Spring and has
submitted his resignation as Co-Editor. He and I have enjoyed working
together on the
"Newsletter" since March, 1992, and I'd like to publically
thank him for his sterling efforts on
behalf of our Division during that time.
As usual, I'd like to encourage Division members and students in structure
and
tectonics to participate in the "Newsletter" by sending in
your views and opinions to "Letters to
the Editor", by contributing people-related news to the "Have
You Heard ...?" column, by
informing us of future conferences and meetings, and by submitting
reviews of your favorite
new book or items of interest to be included in the "Resource
Bin" (our usual listing of non-
profit materials that are likely to be of use to some of us in teaching
or research endeavors).
Suggestions for improvement of the "Newsletter" are always
welcomed.
Appreciation is extended to Tom Wright, Eldridge Moores, Terry Pavlis,
and Steve
Schimmrich for their special contributions to this issue (apart from
symposia and theme session
summaries), and to my numerous colleagues who contributed news of Division
members for
the "Have You Heard ...?" column.
Greg Davis, Dept. of Earth Sciences, Univ. S. Calif., Los Angeles,CA
90089
phone: (213) 740-6126; fax (213) 740-8801; email: gdavis@usc.edu
LETTER TO THE EDITORS
Dear Editors:
I Have a Dream: A Request for Input on a Planning Workshop for
Revitalization of Field Geology
A lot of us in this business got into geology, at least in part, because
of the
opportunities for field work. With all of our fancy high-tech equipment
these days we often
tend to loose sight of that fact that geology is based on observations
in the field. There is no
more sobering way to have your hypothesis destroyed than to discover
that that marvelous idea
you had just evaporated when you walked over a hill and saw something
unexpected.
Despite its importance, many people have moved away from doing basic
field work. This
results in large part because Deans, or for that matter Congressmen
looking at agencies like the
Geological Survey, see a tendency for "low productivity"
of individuals who are heavily
involved in activities that involve a lot of geologic mapping. I contend
that this perception is
absolutely correct -- field geologists typically are not very "productive"
because their "product"
is labor intensive and time consuming. I also contend, however, that
most of this is our own
fault because much of what we do is unbelievably inefficient. For example,
how many of you,
like me, have procrastinated for months because you needed to compile
all of your field maps
for this paper or that, but couldn't face the endless, tedious hours
drawing lines, plotting
symbols, and double checking all of this? I might add that I do all
my maps on a computer
these days, so it isn't simply a matter of using a computer to speed
up the operation.
What is my point? Aside from basic physical limitations of walking
from point A to B, a
lot of the inefficiencies of field geology could be eliminated with
some proper applications of
technology. Why can't we make a simple, digital recording compass?
Why can't we routinely
use GPS to get exact locations, including a record of our traverses?
(Note -- with properly
georeferenced orientation data a geologic map becomes increasingly
more a piece of data rather
than a mixture of data and interpretation as it now is). Why can't
we have a ruggedized field
computer that could be used for routine mapping? Better yet, why not
be able to display
DEM's constructed from satellite images and be able to view that model
from any vantage point
the person wants -- i.e. show me the view in front of me at azimuth
280°, then "fly" upward to
a vertical view? Why not record all our observations as digital images
and place them in a real
spatial data base rather than the endless piles of kodachrome slides
which many of us now
own.
The critical thing is that everything I just stated in the above paragraph
exists in some form
or another. Some of you are already using some of these things, but
I firmly believe we need a
unified approach with some common formats and some standard software/hardware
packages.
The problem, as with all things eventually, is that all of this costs
money. If we want to apply
this kind of technology to field problems, we can't live in the isolation
of the "lonely field
geologist wandering around the countryside". Geologists have traditionally
been a solitary lot
fighting over turf, but this is a situation where that simply won't
work. Geophysicists long
ago recognized the need to band together when equipment acquisition
or manpower needs were
too large for individual workers. Look at organizations like IRIS or
UNAVCO for an
example. In these organizations, expensive equipment is shared by numerous
institutions.
Could we do a similar thing in the Structure and Tectonics community
by forming an
organization?
If this idea interests you, please contact me. I am trying to assemble
a list of names with
some suggestions to put together a workshop addressing this problem.
Since this is supposed
to be a high-tech plan, please contact me by e-mail (tpavlis@geology.uno.edu).
If you really
want to speak to a human call me (504-286-6797), but I have a mind
like a sieve so without
some electronic copy I may loose track of you. Please, no paper communication!
Terry Pavlis, Department of Geology and Geophysics
University of New Orleans, New Orleans, Louisiana
HEALTH ALERTS FOR FIELD SCIENTISTS:
A CONTINUING SERIES
This is the fourth in a series of articles concerning possible disease-related
health risks
that field scientists may encounter. Previous editions of the "Newsletter"
have treated
Hantavirus pulmonary syndrome (March, 1994, 1995), coccidiodomycosis
(Valley fever) and
Lyme disease (March, 1995); and malaria and plague (September, 1995).
This issue's column
is concerned with giardia (giardiasis) and dengue fever. The information
cited below comes
primarily from publications supplied by the Center for Disease Control
and Prevention,
Atlanta, Georgia, including the Center's "Health Information for
International Travel 1994"
(U. S. Dept. of Health and Human Services Publication No. [CDC] 94-8280,
for sale by the
Superintendent of Documents, U. S. Government Printing Office, [202]
783-3238).
International travelers can obtain current health information on specific
countries from the
CDC's automated travelers' hotline -- accessible from a touchtone phone,
24 hours-a-day, 7
days-a-week; the number is (404) 332-4559. It is recommended that you
make your inquiry at
least 6 weeks prior to departure.
Another reference of potential interest to field scientists working
overseas is "Staying
Healthy in Asia, Africa, and Latin America" by D. G. Schroeder,
Moon Publications, Inc., P.
O. Box 3040, Chico, CA 95927-3040, $10.95 (paper, 180 p.). If microorganisms
and their
evolving interactions with humankind intrigue you, read "The Coming
Plague (Newly
Emerging Diseases in a World Out of Balance)" by Laurie Garrett,
1994, Penguin Books, 750
p. [ISBN 0 14 02.5091 3 (pbk.), $14.95 US, $19.99 Can.]. This marvelously
researched but
easily read book may just be the most fascinating -- and worrisome
-- book you'll ever read!
Now, on to giardia ...
Giardia
Back from the field, or perhaps from a visit to a third-world country,
and feeling that
your GI track isn't behaving the way it should? Experiencing symptoms
of diarrhea (with foul
smelling, frothy stools [sorry ...]), weakness or malaise, abdominal
cramps, abdominal
bloating, nausea, flatulence, weight loss and uncommon fever? Then
you should consider that
you may be the victim of giardia (giardiasis), a waterborne parasitic
disease that occurs
worldwide. The culprit for this disease is the one-celled organism
Giardia lamblia.. It and
Cryptosporidium are the most widespread intestinal parasites in the
United States. Giardia is
the cause of millions of infections worldwide. Although most cases
of domestic giardia come
from fecally contaminated municipal water supplies that are not adequately
treated, field
workers and international travelers are next at risk. A trip to Leningrad,
Russia, is the surest
way on the Eurasian continent for travelers to contact the disease.
As parasitologist Dennis
Juranek of the CDC reports in his summary "Giardiasis" (from
which most of this information
was taken) "hikers and campers risk infection every time they
drink untreated raw water from a
stream or river." Don't be enticed by sparkling clear water; it
too may be contaminated.
Giardia lamblia occurs in two forms -- the active parasite (a trophozoite)
and its
dormant, egglike form -- a thickwalled cyst about 9 to 9 micrometers
in diameter and 8 to 12
micrometers (.001 mm) in length. The infected person has somehow ingested
10 or more of
the cysts, usually from fecally contaminated water. Once in the stomach,
acids and enzymes
dissolve the outer wall of the cysts and free the parasites. They then
attach themselves to the
upper small intestine where they feed and reproduce by binary fission
every 12 hours. (And
how!) A single cyst reproducing at this rate will generate "more
than 1 million parasites 10
days later" (D. Juranek), and more than one billion parasites
soon thereafter. (Arghh...!)
After some period of time, the trophozoite detaches itself from the
intestinal lining and floats
downward through the intestinal track. As it does so, it metamorphoses
into its cyst-like form
and is excreted back into the environment.
Most untreated cases of giardia persist for only one or two months
("only"?); no
permanent damage to the intestinal track results from infection. Some
infected people may
have various symptoms listed above other than diarrhea, whereas in
others episodes of diarrhea
occur only every three of four days. Treatment of the disease, which
can be identified (but not
always easily) by laboratory examination of stool specimens, is relatively
effective (>90%) by
the prescribed drugs quinacrine (trade name: Atabrine) and metronidazole
(trade name: Flagyl).
Prevention is easier. Don't drink untreated stream or river waters
and be cautious of
urban water supplies in underdeveloped countries. If you must drink
such water, boil it (100°
C) for one minute or strain it through filters which block particles
in the 1-3 micrometer range;
ceramic filters (e.g. Katadyn) work best, but read their filtering
specifications. Chemical filters
using various iodine compounds can't be relied upon, according to the
CDC, to kill all of the
cysts. Chlorinated water will not always kill giardia cysts. Tincture
of iodine (2%) can be
effective if used in the following proportions (5 drops/quart or liter
if clear; 10 drops if cold
[<50° F] or cloudy), mixed thoroughly, and allowed to stand for
at least 30 minutes -- 60
minutes or overnight if the water is cold or turbid.
Dengue fever/dengue hemorrhagic fever
Bad news, folks, for those of you planning on fieldwork in tropical
areas of the world.
The incidence of dengue (pronounced den-gey -- rhymes with "key"
-- or den-gay) fever, a
mosquito-borne viral disease for which there is neither treatment nor
cure, has increasing
dramatically over the past 25 years on a worldwide basis. The CDC reports
that "there are now
over 2 billion persons at risk of infection and millions of cases occur
each year. ... It is
anticipated that there will be increased dengue transmission in all
tropical areas of the world
during the next several years."
Closer to home, a dengue fever epidemic that began in 1994 is sweeping
through
Central America, Mexico, and the Caribean. In the first 9 months of
1995, 35,000 cases of the
fever were reported in these areas, as well as 545 cases of its more
severe form, dengue
hemorrhagic fever (DHF). Fortunately, the death rate from the fever
is low with only 24 cases
from the thousands of infections according to the Pan American Health
Organization. Mexico
reported 2500 of the 35,000 cases; an American visitor to Reynosa,
12 miles south of the
border at McAllen, Texas, contracted the disease there. There are four
dengue viruses
transmitted to humans through the bite of Aedes mosquitoes (usually
Aedes aegypti); infection
from any one of the four does not immunize humans against the others.
Dengue fever has as its symptoms the sudden onset of high fever (up
to 104° F.),
severe frontal headache, and intense muscle and joint pain that has
given the disease its
nickname of "breakbone fever". The disease has an incubation
period of three to 15 days, so
that travelers may have returned home before its onset. Nausea and
vomiting are common
additional symptoms. After 2 to 4 days the fever vanishes, but a day
later is likely to return. A
rash appears on the torso 3 to 5 days after the initial fever and may
spread across the body.
The palms of hands and soles of feet may become red and swollen. Symptoms
gradually
diminish, but the weakness that accompanies this disease may last for
several weeks or longer.
According to Schroeder (reference above) treatment is limited to bed
rest, aspirin for fever,
acetaminophen for headache, and fluids for rehydration. Symptoms in
some lucky individuals
are weak enough to be misdiagnosed as related to flu. DHF is a more
serious form of the
disease in which serious blood vessel damage can occur, and death can
result. Children under
the age of 15 who have had an earlier dengue infection seem to be at
the greatest risk of DHF.
The current spread of the disease is attributed by some experts as
due to cutbacks in
formerly successful mosquito abatement programs, and to shifts and
growth in the human
population. As with giardia, prevention is the key to staying healthy.
The Aedes carrier is
most active in the several hour periods after daybreak and before nightfall
(except indoors or on
overcast days when the mosquito doesn't "watch the clock").
Simple precautions can
dramatically decrease the risk of infection. Wear light-colored protective
clothing over your
arms and legs, avoid scented soaps, and apply DEET (N,N diethylmethylbenzamide)
repellent
with concentrations equal to or more than 20%. Concentrations higher
than 30% are not
recommended by the CDC for direct application to the skin, particularly
in children. In
endemic or epidemic areas the use of bed nets and indoor aerosol insecticides
is advised.
G.D.
BOOK REVIEW
"GEOLOGY OF WESTERN GONDWANA (2000-500 Ma),"
by Roland Trompette, translatedby Albert V. Carozzi:
Balkema, Brookfield, 1994, 350 pp.
For anyone interested in the on-going discussions of the relationship
between Gondwana
and Laurentia (e.g. SWEAT hypothesis), this book is a major publication
event. Trompette
brings together for the first time, to my knowledge, the scattered
and diverse geological data
mainly on two continents, Africa and South America, that document the
amalgamation from
formerly separate land masses that constitute western Gondwana.
Trompette's book comes along at a good time. This work presents a first-time-ever
synthesis of the geologic evidence for amalgamation of western Gondwana
(Africa and South
America and its subsequent suturing with eastern Gondwana (chiefly
India, Australia and
Antarctica). Trompette discusses five formerly separate cratons--Amazonia
(now underlying
Brazil, Venezuela, Surinam, Guyana, French Guiana); West Africa (now
underlying Mali,
Senegal, Algeria, Morocco, Ghana, Ivory Coast), Rio de la Plata (now
beneath Brazil,
Uruguay, Argentina); Kalahari (located in Botswana, Zimbabwe, South
Africa); Congo-São
Francisco (in Brazil, Cameroon, Nigeria, Zaire, Central African Republic,
Angola, Zambia,
Congo). He discusses seven specific orogenic belts of late Precambrian-early
Paleozoic age,
collectively comprising the "Pan-African-Braziliano" orogenic
system. This division is, of
course, somewhat arbitrary, as the belts are continuous with each other.
The belts Trompette
describes are: 1. Trans-Sahara from Ghana to the Hoggar massif; 2.
West Congo-Araçuai and
Ribeira belts, which are located along the Atlantic margin of NE Brazil
and its African
conjugate margin; 3. the Brasilia fold belt in central Brazil; 4. the
Dom Feliciano-Kaoko-
Gariep-Malmesbury of southern Brazil, Uruguay, Namibia, and South Africa;
5. the Damara
of South Africa-Namibia; 6. the Oubanguide-Sergipe orogen of Congo-Zaire
and east-central
Brazil; and 7. a series of belts extending from Mauritania through
central Brazil and Paraguay
to the Sierras Pampeanas of Argentina. Trompette also presents an interesting
scenario of
assembly of Gondwana starting about 650 Ma by early amalgamation of
West Africa and
Amazonia followed successively by addition of the Congo-São Francisco
and Kalahari cratons,
and finally at about 500 Ma the collision of West and East Gondwana.
We owe Albert V. Carozzi a large debt of gratitude for his excellent
translation.
Nevertheless, this dense, compactly written, stratigraphically-oriented
book is somewhat heavy
going. Many may disagree with some of Trompette's conclusions. However,
it is hard to
overemphasize the book's value for present and future tectonic discussions.
It's all here --
even the ophiolites, if you look hard! The reference list alone --
approximately 1400 entries in
four languages (Portugese, Spanish, French, English) -- should serve
for years as a valuable
research and teaching aid for any geologist interested in this vast
and important region.
E. M. Moores, Department of Geology,
University of California, Davis, CA 95616
HAVE YOU HEARD ...?
Have you heard of the contribution of our Division membership to geological
affairs of
state? Eldridge Moores is currently president of the GSA, George Thompson
is vice-
president, and Dave Dunn is treasurer. All are Division members, as
is Bob Hatcher,
current president of the American Geological Institute. As are Pinar
Yilmaz, past president
of GSA's International Division, Jim Skehan, the current president
and Ian Dalziel, that
Division's vice-president. There must be truth in that old "T-shirt"
adage that "tectonicists do it
better!" Hmmm.... Hearty congratulations to John Suppe and Marylou
Zoback
(Geophysics Division) who are the latest earth scientists to be elected
to the National Academy
of Sciences; their elections become official in April.
As always, there are new faculty appointments to be announced, but
the list is fairly
short. Mark Fischer (Ph.D. from Penn State under adviser Terry Engelder)
has left
Exxon Production Research for a faculty position at Northern Illinois
University. Another
Mark -- Evans -- has moved north from Georgia Southern University to
assume an Adjunct
Professorship at the University of Pittsburgh (Johnston campus). John
Oldow, in another
south to north migration, has left Houston, Texas, to become the new
Head of the Department
of Geology and Geological Engineering at the University of Idaho in
Pocatello. The faculty
slot at Grand Valley State University, Allendale, Michigan, has been
filled by the appointment
of John Weber (Northwestern U. Ph.D. under Seth Stein), whose dissertation
"New
Madrid seismic zone deformation from repeat GPS surveys" sounds
like cutting-edge
neotectonics stuff. Within that zone lies Memphis, Tennessee, where
Randel Tom Cox
(Ph.D., Missouri at Columbia, adviser George Viele) has taken a temporary
position at the
University of Memphis. Linda Reinen and Eric Grosfils, a recently married
couple with
Ph.D.s from Brown University, began sharing a faculty appointment at
Pomona College,
southern California, last fall. Sounds like a super deal for Pomona!
Post-doctoral positions continue to be of importance in putting the
talents of the
younger doctoral generation to work, although cuts in research funding
are taking their toll on
the availability of such positions. John Suppe is certainly doing his
share! Three new
postdocs have arrived at Princeton in recent months to work with John:
Delphine Rouby, a
student of Peter Cobbold at University of Rennes, France, working on
3-D restorations;
Pablol Kraemer from the University of Cordoba, Argentina, studying
the structure of the
Patagonian Andes; and Xin Wang, Institute of Oceanography, Chingdao,
China, working on
the tectonics of China. Julie Newman (a recent Gautam Mitra Ph.D. at
Rochester) has
won a senior research position with M. Drury's group at Utrecht, The
Netherlands; she'll be
investigating mantle shear zones. Carole Simpson's much sought after
post-doc position at
Boston University has been filled by Jay Busch (Ph.D.,'96,Univ. of
Michigan); his advisers
at UM were Eric Essene and Ben van der Pluijm. One post-doc position
being
advertised in the January 25th issue of "Nature" sounds like
a lot to handle. The University of
Reading, U.K., advertises a postdoctoral research fellowship in geophysics
designed to
undertake lab measurements of elastic and anelastic properties of rocks
and sediments. Says
the ad, "You will require considerable research expertise in laboratory
geophysical
measurement techniques (at pressures up to 70 MPa)." Talk about
a high pressure job!
(Some of us have problems working well at even 1 atmosphere.)
Miscellany that's come my way: John Craddock has won a much-deserved
promotion to Associate Prof with tenure at Macalester College, where
he's also been appointed
Chair of his department. How's that for a mixed blessing? Petrology-tectonics-type
Karl
Wirth (a Cornell Ph.D, 1990) was also promoted at Macalester. Wiley
has just published
George Davis' and Steve Reynolds' book "Structural Geology of
Rocks and Regions",
the second edition of George's original popular text. As I've told
George before, I've often
been complimented for writing his first edition. I always tell the
complimenter, "thanks, but
it's not mine, it's by George Davis." (Well .... almost always.
Please, George, forgive me.)
International news: The Geological Society of South Africa celebrated
its 100th year
with a Centennial Geocongress held in Johannesbury last April. Among
members of our
Division in attendance, Sam Bowring and Kevin Burke presented major
lectures. Kevin
was honored by being asked to deliver the 24th Alex L. Du Toit Memorial
Lecture; his talk,
"The African plate: its distinctive behavior over the past 30
million years," will be published in
September in the GSSA's "Journal." The Structural Geology
and Tectonics Division of the
Geological Association of Canada has announced their choice for the
1994-1995 Best Paper
Award, given annually to the best paper of the year by Canadian authors
or dealing with
Canadian structural geology and tectonics. This year's winner: a "JSG"
paper entitled
"Kinematics of rock flow and the interpretation of geological
structures, with particular
reference to shear zones"; its authors are Dazhi Jiang and Joseph
Clancy White, both of
the University of New Brunswick. The new executives of the SGTD are
Chairman
Alexander (Sandy) Cruden of the Erindale Campus, University of Toronto
and a member
of our Division, Treasurer Paula McKinnon, and Secretary Frank Fueten,
both of Brock
University, Ontario.
Sad notes: paleomagneticist Keith Runcorn, whose work in the 1950's
lent credence
to continental drift and helped lay the foundation for plate tectonics,
has passed away.
Is it any wonder after losing 525 employees last fall that despair
reigns throughout
some quarters of the U.S.G.S. these days? One of its members who survived
the recent
bloodletting writes that "the USGS is (1) technically back to
work after the government
shutdown, but without operating funds to do anything, and (2) morally
and intellectually
bankrupt after self disembowelment during the reduction-in-force."
Matters could get worse!
David Applegate, Director of AGI Government Affairs, reports in the
January, 1996, issue of
"Geotimes" that the Republican dominated Congress is now
considering new legislation that
would require the Department of the Interior to contract out ALL surveying
and mapping
activities to the private sector. Alaskan legislators, who have heard
complaints from private
Alaskan contractors that they are in competition with Interior Department
agencies for aerial
surveys and other work, are strongly pushing such a bill. If you are
opposed to such
legislation, which could strip the USGS of some of its most important
functions, you might
consider writing Senator Frank Murkowski (R-Alaska) and Representative
Don Young (R-
Alaska) who head, respectively, the Senate Committee on Energy and
Natural Resources and
the House Resources Committee. How did that happen?
And finally, have you heard the news that we've all been waiting for?
A Japanese
professor, Yasumasa Kanada of Tokyo University, has proudly announced
that he has
calculated the most accurate value of ¹ to date -- to 6,442,450,000
decimal places. Now,
that's a lot of pi, no matter how you slice it!
G.D.
INTERNATIONAL ASSOCIATION
OF STRUCTURAL/TECTONIC GEOLOGISTS (IASTG)
Sue Treagus, IASTG Coordinator, has announced in the "International
Newsletter 11"
of the IASTG (JSG, v. 1l8, no. 1, p. I-V) that membership in the Association
has now reached
1080+ since its founding five years ago. The Association's purpose
is to foster international
communication among structural and tectonic geologists worldwide. Membership
is open,
without mandatory fees or subscription to the "Journal of Structural
Geology", although new
members do receive an invitation to subscribe to the JSG at a reduced
personal rate. A
"Newsletter" for the Association is printed twice yearly
in the JSG and contains a summary
report on the IASTG, announcements of scientific meetings of interest
to the members (usually
with abstract deadlines), information on international structure/tectonics
organizations, and
reports of completed meetings or proposed research ventures. A "Membership
Directory, 2nd
Ed." in booklet form was mailed to members in April, 1995, free
of charge.
Persons interested in joining the IASTG can do so by completing a membership
form
copied from the "International Newsletter 5", JSG, v. 15,
no. 1, 1993, or by requesting a form
from Coordinator Treagus (address below). Or, apply by email to: iastg@man.ac.uk;
send in
your name, title, address, phone, fax and email numbers, plus a statement
(<20 words) of your
research interests. The email address can also be used to send in materials
or non-commercial
announcements for the "International Newsletter" (please
use ASCII TEXT for attached files),
or to report changes of address. An IASTG Homepage on the WWW provides
a brief
background on the Association and access to the most current "International
Newsletter"; its
URL (Uniform Resource Locator) is: http://info.mcc.ac.uk/Geology/IASTG.
Voluntary contributions in support of IASTG activities are most welcome
and should
be made payable to the "IASTG Fund", c/o S. H. Treagus, Dept.
of Earth Sciences,
Manchester University, Manchester, M13 9PL. U.K.; fax 44 161 275-3947;
email:
iastg@man.ac.uk.
ANNUAL MEETING SYMPOSIUM SUMMARIES
"Products and Processes of Continental Extension"
(co-sponsored by SG&T and Geophysics Divisions)
Conveners: John Bartley (University of Utah) and John Geissman (University
of New Mexico)
The morning session of this all-Monday symposium focused on low-angle
normal
faults, an issue that has sparked a controversy so spirited that Richard
Kerr, in the news
section of "Science" in a late November issue (11/24), featured
Greg Davis and Roger Buck,
two prominent protagonists in the debate who presented their views
in the symposium. After a
quarter of a century of field mapping and geophysical imaging of gently
dipping normal faults,
little doubt remains regarding their widespread occurrence. The still-lively
debate now has
shifted to whether low-angle normal faults nucleate at and/or are active
at their present low dips
and, if they are active at low dips, what physical conditions permit
them to slip and whether or
not they generate earthquakes.
Presentations by Greg Davis, Rick Liviccari, and Steve Reynolds summarized
a plethora of observations from field structural studies, thermobarometry
and
thermochronology, seismic reflection imaging, and paleomagnetism that
indicate that low-angle
normal faults in the lower Colorado River trough - southern Arizona
corridor were active and
probably initiated with dips less than 20 to 30°. Brian Wernicke proposed
a simple
seismotectonic model that may account for the lack of large historic
low-angle normal fault
earthquakes. The model predicts that low-angle normal faults release
fewer but larger
magnitude earthquakes than high-angle normal faults, with the implication
that large low-angle
normal fault earthquakes may be intrinsically rare and are not, therefore,
underrepresented in
historic seismicity. Gary Axen overviewed field tests of isostatic
"rolling hinge" models.
The data suggest that such rolling hinges do exist and, in some cases,
have led to appreciable
tilting of normal faults into their present low-angle orientation.
However, Axen concluded that
the rolling hinge model cannot be applied universally and that field
data continue to favor the
existence of active low-angle normal faults.
A group of skeptics, all coincidentally from Lamont-Doherty Earth Observatory
(!),
presented their perspectives. Roger Buck examined two classes of proposed
solutions to the
mechanical problems of initiation of, and slip along low-angle normal
faults. Stress-field
reorientation by additional loads runs into trouble because loci of
maximum reorientation
support differential stresses too low to cause faulting. The argument
that low-angle normal
faults are energetically favored over high-angle faults because they
require less stored elastic
strain appears to break down when failure in response to flexural loads
is included in the
calculation. The gulf between some rock mechanists and a large cadre
of field geologists
seems as wide as ever!
Mark Anders and Stewart Wills, also of LDEO, then focussed attention
on the
Sevier Desert "reflector" of southwest Utah, a low-angle
feature first seismically imaged during
oil exploration 20 years ago. This group interprets the reflective
horizon as an unconformity
rather than an active extensional detachment, primarily based on a
lack of microstructural
evidence for the fault in drill cuttings. The reliability of microstructural
observations of
cuttings and the correlation of drill-hole depth to the seismic record
section was challenged, and
some regional-tectonic problems caused by discarding the detachment
were raised. Few fans
of the Sevier Desert detachment appear to have been converted. Nevertheless,
the lack of direct
structural evidence for a fault in the borehole at an appropriate depth
is troubling and further
work on the character of the Sevier Desert reflector is warranted.
The morning session ended with Julia Miller and Julio Friedman discussing
the
sedimentary and geomorphic characteristics of supradetachment basins,
and Rick
Groshong's presentation of quantitative methods for recovering strain
magnitudes and
detachment depths and geometries from analysis of shallow normal fault
systems.
The afternoon session turned to crustal and lithospheric structure
and the relationships
between crustal extension and magmatism. Gene Humphreys discussed his
provocative
hypothesis for the origin of large areas of the Basin and Range province
characterized by high-
velocity upper mantle, relatively thin crust, and high surface elevation.
He invokes extraction
from the upper mantle of a high percentage of partial melt, leaving
a high-velocity, low-density
dunite-harzburgite residuum. The implication of a corresponding pattern
of large volumes of
mafic igneous rocks in the crust needs to be tested.
Randy Keller and Jill McCarthy reviewed geophysical studies of rift
crustal
structure and emphasized the great variation in the volume of magmatism,
which is strongly
expressed in the resulting crustal structure. Geologic studies of magmatism
and extension
discussion by Mai-Britt Shaw, Drew Coleman, John Bartley, and Jeff
Karson
revealed some common threads. Association of magmatism in time and
space with crustal
extension has a dramatic effect on tectonic style. A significant amount
of dilation may result
from igneous intrusion rather than by solid-state deformation and the
style of the deformation is
greatly affected. Close association of extension and magmatism in space
does not validate the
common assumption of their association in time and, therefore, thermal
weakening of crust by
magmatism need not have played a role in structural evolution -- even
in rifts where igneous
rocks of broadly similar age are abundant.
Clark Burchfiel, C. J. Northrup, and Leigh Royden concluded the symposium
with field and theoretical studies of crustal extension within contractional
belts. Clark
presented recent observations of intricate relations among extensional,
transcurrent, and
contractional structures along the eastern margin of Tibetan Plateau.
C. J. discussed evidence
for extensional general shear of thrust nappes in the northern Scandinavian
Caledonides during
their emplacement. This type of strain field results in upper-crustal
extension within the nappes
even as they are being emplaced by thrusting, an apparent paradox that
has recently been
inferred in several mountain belts. Leigh presented numerical models
of the interaction
between lithospheric shortening and surface topography to account for
the patterns of surface
deformation (contractional and extensional), topography, and the progressive
growth of
mountain belts. The models indicate that a weak intracrustal decoupling
zone is required for
upper-crustal extension in a contractional orogen, and that extension
is localized at steep
topographic gradients at the orogen's margins.
The well-attended symposium illustrated the diversity of current research
on extensional
tectonics, and revealed fundamental problems that remain unsolved:
the nature and mechanics
of low-angle normal faults; an overall conceptual framework for relations
between magmatism
and crustal extension; and a full understanding of the significance
of upper-crustal extension
within contractional orogens. Impressive progress has been made in
the last decade through
the efforts of far more investigators than were directly represented
in the symposium, and we
hopefully will see similar progress in the future!
The conveners have initiated work on a GSA Special Paper that will
include papers
from most of the participants in the symposium.
John M. Bartley, Dept. of Geology & Geophysics, Univ. Utah, SLC,
84112
*****
"25+ Years of Plate Tectonics: Where Do We Go From Here?"
Conveners: Terry Pavlis and Laura Serpa (University of New Orleans)
The idea for this symposium originated at the 1994 JTPC meeting in
a discussion
between us and the SG&T and Geophysics Division reps at that meeting.
We all agreed that it
might be fun to run a special symposium at New Orleans because 25 years
had passed since
1970, a watershed year when plate tectonics really became widely accepted
by geologists. This
occurred in large part through a series of landmark papers published
around that time. Clearly
plate tectonics senso stricto had really existed for several years
by that time, but because of the
"acceptance factor" we came up with the rather odd title
of "25+ years..." for this symposium.
Because of the timing we thought it would be appropriate to have retrospective
and forward
views from some of the people who were a major influence 25 years ago.
There are a lot of
people who fit that description, so we attempted to limit the group
to a few speakers from a
variety of subdisciplines whom we knew we could count on to give presentations
that would
be philosophical, crowd-pleasing, thought-provoking, and forward-looking.
I think everyone
who attended the sessions can agree that the group did a very nice
job of fulfilling our wishes!
Certainly the crowds at the sessions were a complement to the group--the
only complaint we
heard was that this session emptied some of the other concurrent sessions.
It is difficult to summarize in a few words what was said in this session
but a few points
were clearly memorable. Bill Dickinson, for example, gave a great summary
of advances
in sedimentary geology and surprised many by suggesting that we should
abandon the term
"orogeny" and "orogenesis" in geology because they
are archaeic remnants of vertical tectonics
and the terms can be misleading because all plate tectonic processes
can produce large vertical
uplifts despite very different underlying causes. Dave Scholl then
gave a great "confession
of a sinner" description of how our views have changed on convergent
margin systems.
Eldridge Moores discussed how our knowledge of ophiolites and oceanic
lithosphere has
grown over the years, but that increasing evidence shows that oceanic
crustral thickness has
decreased through earth history; a factor that has many ramifications
for sea-level variations
and variations in erosional processes through time. Kevin Burke then
returned attention to
the continents with a thought provoking series of observations and
discussions of a number of
unusual topographic features on earth that have yet to be fully explained.
Peter Coney
discussed the great strides made in continental orogenesis using the
plate tectonic paradigm and
the philosophical pitfalls in applying strict rules to Precambrian
systems where the rules may be
different. Gary Ernst and Jack Bird addressed one of the key problems
in tectonics; i.e.
what is happening deep within the earth -- first with Gary's discussion
of the origin of ultra-
high- pressure metamorphic rocks and then Jack's discussion of materials
that may be derived
from as deep as the earth's core. Jack Oliver then moved to a more
philosphical side and
with his usual flare gave some great forecasts of where tectonics might
be in the next 25 years
-- one noteable quote that was probably remembered by all was that
new technological
developments probably mean that the whole world would need to be "remapped"
into a digital
data base format! Finally, Tanya Atwater completed the session with
an upbeat note that
many recent technological developments, together with the accumulation
of basic information,
have made it possible to finally relate directly the marine plate tectonics
record to on-land
geology. She believes that there is a rich future in such tectonic
endeavors.
Laura Serpa and Terry Pavlis, Department of Geology and Geophysics,
University of New Orleans, New Orleans, LA 70148
*****
"Geology and Tectonics of the Caribbean Region"
Conveners: Hans Ave´ Lallemant and Jinny Sisson (Rice University) and
Gren
Draper (Florida International University)
Notwithstanding the demise of the Caribbean Basin Initiative proposed
about a decade
ago by our political leaders in Washington, interest in at least the
geologic and tectonic aspects
of the region appears to be flourishing and on the rise. ln the last
few years symposia dealing
with the Caribbean were organized at almost every national meeting
of one or the other earth
science societies. Thus, it was not a surprise that the organizing
committee for the 1995
Annual Meeting of the GSA in New Orleans thought it to be timely to
have such a symposium
too.
The reason for the interest in the Caribbean lithospheric plate may
be the fact that it is a
very special plate: it is very small; it has an unusually thick crust;
and it has virtually no means
to propel itself (no real subduction zone to pull it, nor a mid-oceanic
ridge to push it). Many
global-scale phenomena taking place along plate boundaries occur here
in rather small areas and
can be studied without extensive travel. And, of course, the beaches
are great!
The symposium and the accompanying poster session were sponsored by
the Society's
International Division and had the blessing of the IGCP (Projecat 364:
Caribbean Arcs and
Ophiolites). This made it possible among other things to invite Manuel
Iturralde-Vincent
to participate and give us a masterful lecture on the latest model
for the geology of Cuba.
A historic review of the geology and plate tectonics of the Caribbean
region (Gren
Draper and Jim Pindell) was followed by characterizations of the Caribbean
plate
boundaries that included seismicity (Ray Russo), recent relative plate
motions based on GPS
data (Timothy Dixon), deformation in subduction zones (Casey Moore
and others), and
contrasting arc volcanism in the Lesser Antilles and Panama arcs (Mike
Carr). The internal
structure of the Caribbean plate was discussed by Stuart Hall. Subsequently,
portions of the
plate boundary were discussed in a geographic sequence starting in
the northwest with the
Cayman leaky transform (Eric Rosencrantz) and the fragmented Nicaraguan
Rise (Andre
Droxler) and following a clockwise loop through Cuba (see above). Then
came treatment of
the exotic allochthonous radiolarian cherts of the northeastern Greater
Antilles and Lesser
Antilles proving to everybody's(?) satisfaction that the Caribbean
plate once was part of the
Pacific Basin (Homer Montgomery). Then off to the southeastern corner
where very large
thrust displacements resulting from convergence between the Caribbean
plate and the South
American continent were proposed by Bert Bally and his students. The
last talk dealt with
the catastrophic deposits resulting from the bolide impact at the K/T
boundary in the Yucatan
Peninsula (Florentin Maurasse). The symposium was very successful in
that it brought
researchers with very different expertise together. It showed exciting
new ventures and areas
where new research is desparately needed.
Hans G. Ave´ Lallemant, Dept. of Geology and Geophysics,
Rice University, Houston, Texas 77005
*****
ANNUAL MEETING THEME SESSION SUMMARY
"Before the Gulf --
Paleozoic Tectonics of the Southern Margin of Laurentia"
Convener: George W. Viele (University of Missouri, Columbia)
This theme session addressed three major topics: the relationship of
the Precordilleran
terrane of Argentina to Laurentia; the nature of the Ouachita interior
metamorphic belt of Texas;
and the late Paleozoic closing of the Ouachita Ocean.
Several authors -- Astini and others, Hatcher, Krekeler and others,
Thomas
-- reviewed the stratigraphic, petrologic, and paleontologic data linking
the Precordilleran
terrane of Argentina with Laurentia during the Early Cambrian and the
subsequent rifting,
drifting and docking of the Precordillera with Gondwana before the
end of the Ordovician.
Discussion continued, however, about the distance of Laurentia from
Gondwana or indeed if
they collided during the Ordovician. Did the Precordillera leave a
wide spreading ocean behind
the Ouachita embayment as it split away from Laurentia, or did it --
as Dalziel suggested
during a question period -- remain attached to Laurentia via an oceanic
plateau. He compared
this model to the present-day linkage between the Falklands and Argentina.
Dix and others reported on an Ordovician clastic wedge in the Broken
Bow uplift of
Oklahoma and suggested that it was derived from the collided eastern
margin of the
Precordillera and Gondwana; this implies a narrow Ouachita ocean. Dickerson
described
complicated early Palezoic interactions that occurred at the Marathon
end of the Ouachitas
between the Laurentian margin and a volcanic/sedimentary/metamorphic
terrane (Gondwanan
?) to the south.
The symposium moved on to the closing of the Ouachita ocean. Three
papers: Long
and others, Carpenter and Long, and Gleason and others, dealt with
the interior or
Llanorian side of the Ouachita orogenic belt. New subsurface data and
recent mapping in the
Sierra Del Carmen of Mexico, coupled with isotopic analysis, indicated
an early Paleozoic
protolith for the Ouachita interior metamorphic belt, which was probably
allochthonous to
North America. Gleason's Sm-Nd data indicated the Mississippian tuffs
of the Ouachitas
came from a volcanic arc constructed on older continental basement
(Grenvillian ?). Having
different isotopic signatures, the Mississippian tuffs can no longer
be attributed to the late
Paleozoic subsurface volcanic rocks of the Sabine uplift. (Damn!)
Mars and Whiting and Thomas linked Mississippian stratigraphy and Carboni-
ferous subsidence of the Black Warrior Basin to Ouachita collision
events. Donovan reported
on the Pennsylvanian structures of the Slick Hills of Oklahoma, which
record northeast-
southwest shortening directly athwart the direction of Ouachita shortening,
an unsolved puzzle
for geologists working in southeastern Oklahoma. Muehlberger reported
on the complicated
Ouachita structures in theSolitario region of the Big Bend region of
Texas, and Viele reviewed
the evidence for strain partitioning resulting from a southeastward
direction of closing of the
Ouachita ocean in Oklahoma and Arkansas. Lille finished the symposium
by reviewing the
gravity models of the Ouachitas and Carpathians and suggesting that
both were "soft"
collisions where less than 100 km of crustal shortening occurred after
ocean closure.
Discussions about the opening phase of the Ouachita ocean and its relation
to the
Argentine Precordillera will continue in March at the South Central
GSA meeting. I will argue
for a wide and deep Ouachita ocean. Moreover, in the field, Ouachita
afficionados will
continue to explore the structure and stratigraphy associated with
the late Paleozoic Ouachita
collision, happily turning up new problems as old ones are solved --
or so we think!
George Viele, Dept. of Geological Sciences,
University of Missouri, Columbia, MO 65211
STRUCTURAL GEOLOGY ON THE WEB
The World-Wide Web
The World-Wide Web is a subdivision of the Internet, a vast network
of interconnected
computers which allows you to seamlessly access multimedia information
(text, images, and
binary files) from Web servers anywhere in the world. There are currently
well over 100,000
active Web servers with more coming on-line each day.
To learn more about the Internet, the World-Wide Web, or netbrowser
programs (I
strongly recommend the program Netscape) which allow you to "surf"
the Web, a visit to any
library or bookstore will reveal dozens of books and tutorials for
beginners. Two words of
advise. First, don't waste your money purchasing books on how to construct
your own Web
pages. Once you learn to navigate the Web, you'll see that all of this
information is available
on-line (e.g. http://www.yahoo.com/Computers_and_Internet/ Internet/World_Wide_Web/).
Secondly, don't bother with books containing lists of interesting Web
sites to visit. The Web
is a volatile place with sites literally appearing and disappearing
overnight and such books are
often obsolete by the time they're published. There are many Web search
engines (e.g.
http://ugweb.cs.ualberta.ca/~mentor02/search/search-all.html) which
will allow you to find
most sites quite easily.
Structural Geology Resources
To assist structural geologists in finding useful Web resources, I
have created and
currently maintain a Web site which contains many links to resources
which may be of interest
to structural geologists. The address for the Web page is:
http://hercules.geology.uiuc.edu/~schimmri/geology/structure.html
and the following is a brief outline of the different types of resources
available from this site.
Data Sets and Bibliographies
There are several GIS-type data sets available on the Web which may
be of interest to
structural geologists. In addition, an increasing number of earth science
journals are placing
abstracts on-line and this trend should continue. Some researchers
have placed bibliographies
on Web sites covering, for example, the structural geology of the Andes
(Rick
Allmendinger, Cornell), faults, folds, and joints (Kenneth Cruikshank,
Portland State),
and fluid flow in rocks (Laurel Goodwin and Bill Haneberg, New Mexico
Tech).
Computer Software
Many free and shareware computer programs are available over the Web
if you know
where to look. The Computer Oriented Geological Society (COGS) maintains
an archive of
MS-DOS and Macintosh programs for geologists, and Computers & Geosciences
maintains a
resource list for geological software and archives all programs published
in their journal.
Structural geologists, of course, are interested in plotting and analyzing
orientation data.
Several stereonet and rose diagram plotting programs are freely available
along with assorted
programs for teaching (Rick Allmendinger, Cornell), finite element
modeling (Peter Bird,
UCLA), folding simulations (Ken Cruikshank, Portland State), and paleostress
analysis
(John Gephart, INSTOC and Andy Michael, USGS).
Commercial Products and Services
Several companies now have Web pages with on-line catalogs offering
software, field
equipment, and books of interest to structural geologists.
Organizations
In addition to the Web pages set up by large professional organizations
such as GSA,
AGU, and AAPG, many smaller organizations now have Web pages including
the Canadian
Tectonics Group, the Tectonic Studies Group, and the International
Association of
Structural/Tectonic Geologists. Most organizational Web pages maintain
information about
membership, upcoming meetings, and publications.
Research Information
A few research groups, which may be of interest to structural geologists,
have set up their
own Web pages. Information is available, for example, on the Active
Tectonics Initiative, the
Australian Geodynamics Cooperative Research Centre at CSIRO, and on
salt tectonics research
at the University of Texas in Austin.
Upcoming Meetings
GSA and AGU maintain Web pages with information about upcoming national
meetings,
including submitted abstracts, as well as information on Penrose and
Chapman conferences.
Academic Groups
Several academic structural geology and tectonics groups maintain their
own Web pages.
Some good examples of these are Ben van der Pluijm's group at the University
of
Michigan, Dave Pollard's group at Stanford, and the faults and fluids
group at New Mexico
Tech. These types of Web pages can provide very useful up-to-date information
for
prospective students and other interested parties.
Structural Geologists
Finally, many structural geologists maintain individual Web pages with
information about
their research interests and projects, publications, and personal information.
This resource is
also very useful for prospective students and interested colleagues.
The Future of the Web
Expect the World-Wide Web to continue its exponential growth as an
increasing number of
people gain access to it. Along with this growth will be problems on
how best to handle the
increased traffic and controversial attempts to regulate access and
proper use (such as the
recently passed Telecommunications act).
I see three areas where the Web will continue to be of interest to
structural geologists.
Instant access to information. Do you want to know what geology departments
at other
universities are teaching this semester? Need a colleague's e-mail
address or want to see what
research they've been doing lately? Want to read the abstract of a
paper appearing in last July's
issue of Geology when the library's closed? This information is all
available with a few clicks
of a mouse.
Secondly, I believe that the Web is still greatly underutilized, at
least among geologists,
for the purpose it was originally created in 1989 by CERN -- rapid
dissemination of research
information throughout the scientific community. The Web is an ideal
repository for instantly
accessible information. A published paper, for example, may have a
Web site address
showing interested parties where they may examine the orientation data
used in stereographic
projections, obtain directions to sampling localities, or download
a program developed by the
author.
Finally, the World-Wide Web has a tremendous potential as an aid in
teaching geology.
Many instructors already place course outlines, assignments, and grades
(accessible with a
password) on the Web. Beyond this, there are unlimited opportunities
for developing tutorials
and virtual fieldtrips for geology students in and out of the classroom.
A final caveat, Web surfing can become a very time-consuming addiction!
Steven H. Schimmrich, Department of Geology,
University of Illinois, Urbana, Illinois 61801; email: sschim@uiuc.edu
Editor's note: This is the first in what, hopefully, will be a series
of columns on the World
Wide Web. Steven Schimmrich, a structural geology graduate student
at the University of
Illinois in Urbana-Champaign, has (as mentioned above) put together
a homepage of structural
geology and tectonics resources available on the WWW. These resources
include data sets,
computer programs, and links to organizational and personal homepages
related to structure
and tectonics. Netbrowsers can access his homepage at the address given
above.
THE RESOURCE BIN
Graduate Student Research Grants, Colorado Scientific Society
The Colorado Scientific Society announces the availability of research
grants for M.S
and Ph.D. earth science students involved in field-oriented studies
in Colorado and the Rocky
Mountain region. Approximately eight grants will be awarded in the
$500-$1000 range, and
one grant is available for an engineering geology thesis or dissertation
with no geographic
specifivity. Applications can be obtained from the Chairs of some departments
or by request
from: Chairman, Memorial Funds Committee, Colorado Scientific Society,
P.O. Box 150495,
Lakewood, CO 80215. Application deadline: April 15th.
FUTURE MEETINGS, CONFERENCES, AND COURSES
[Notices of future events of interest to Division members are welcomed.]
1996
April 17-22: Tectonic evolution of the Gulf of California and its margins
(GSA Penrose
Conference): Loreto, Baja California Sur, Mexico. Contact: Paul Umhoefer,
Dept. of
Geology, Box 4099, Northern Arizona Univ., Flagstaff, AZ 86001; phone
(520) 523-
6464; fax (520) 523-9220: email: pju@nauvax.ucc.nau.edu
April 28-May 1: 11th Himalaya-Karakoram-Tibet International Workshop:
Flagstaff, AZ;
for details contacat Allison Macfarlane, Dept. Geography & Earth
Systems Science,
George Mason Univ., Fairfax, VA 22030; phone (703) 993-1207; fax (703)
993-
1216; email: amacfarl@osf1.gmu.edu
May 11-12: Forced (drape) folds and associated fractures (two-day meeting):
London,
England; contact: J. Cosgrove, Geology Dept., Imperial College, Prince
Consort
Road, London SW7 2BP, UK; fax (44) 0171-589-8544; e-mail, dsgorg@ic.ac.uk
May 19-22: Annual meeting, American Association of Petroleum Geologists:
San Diego; for
details contact AAPG Meetings; phone (918) 584-2555; fax (918) 584-0469.
May 20-24: Spring meeting, American Geophysical Union: Baltimore; for
details contact
AGU Meetings; phone (202) 939-3203. Abstract deadline is Feb. 29.
May 26-28: The ocean lithosphere & scientific drilling into the
21st century (symposium and
workshop sponsored by ODO, InterRidge, IAVECI): WHOI, Woods Hole, MA;
contact: Henry Dick, c/o Ms. May Reed, McLean Laboratory, WHOI, Woods
Hole,
MA 02543; email: mreed@whoi.edu. The symposium will review the present
state of
knowledge of the ocean lithosphere; the workshop will seek to establish
goals and
priorities for ocean lithosphere drilling from 1998 to 2003, and to
begin planning for a
new phase od drilling after 2003.
May 27-29: Joint annual meeting, Geological Association of Canada and
Mineralogical
Association of Canada: Winnipeg, Manitoba; for details contact G. S.
Clark, General
Chair, Dept.of Geol. Sci., Univ. of Manitopa, Winnipeg, Manitoba R3T
2N2; phone
(204) 474-8857; fax (204) 261-7581.
June 30-July 4: Composition, structure, and dynamics of the earth's
interior (AGU Gordon
Research Conference; Univ. R. I., co-sponsor): Plymouth State College,
Plymouth,
New Hampshire; contact G. Schubert, UCLA, Dept ESS, Box 951567, LA,
CA
90095-1567; phone (310) 825-4577; fax (310) 825-2779; email:
gschubert@mgnvax.ess.ucla.edu; www http://artemis.ess.ucla.edu
July 29-Aug. 2: Pan Pacific Hazards '96 (international conference):
Vancouver, B. C.; contact
Program Committee, Pan Pacific Hazards '96, U.B.C. Disaster Preparedness
Resources Centre, 2206 East Mall, 4th Fl., Vancouver, V6T 1Z3; phone
(604) 822-
5518; fax (604) 822-6164; email: dprc@unixg.ubc.ca
July 29-Aug. 2: Proterozoic evolution in the North Atlantic realm:
Goose Bay, Labrador;
contact Charles Gower, Newfoundland Dept. of Nat. Resources, P. O.
Box 8700, St.
John's, Newfoundland, A1B 4J6; phone (709) 729-2118; fax (709) 792-3493;
email:
cfg@zeppo.geosurv.gov. nf.ca
August 4-14: 30th International Geological Congress: Beijing, China;
for details contact
Secretariat Bureau, 30th IGC, P. O. Box 823, Beijing 100037, PRC; phone:
86-1-
832-7772; fax: 86-1-832-8928.
Sept. 3-7: Structure and properties of high strain zones in rocks (international
conference and
field trips): Verbania, Italy; organizers: E. H. Rutter & K. H.
Brodie (Univ. of
Manchester, UK) and A. Boriani and L. Burlini (Univ. of Milan, Italy);
contact: L.
Burlini, Centro di Studio Geodinamica, CNR Milano, via Botticelli,
23 -- 20133,
Milano, Italy; fax: 39 2 70638681; email: Burlo@R10.terra.unami.it.
2nd Circular:
2/96; Abst. deadline: April 1, 1996.
Sept. 15-20: Deep seismic profiling of the continents (7th international
symposium):
Asilomar, CA; contact Simon Klemperer, Dept. of Geophysics, Stanford
U.,
Stanford. CA 94305; phone (415) 725-7344; fax (415) 723-7344; email:
klemp@pangea.stanford.edu.
Sept. 17-19: Third international symposium of Andean Geodynamics (ISAG
96): St. Malo,
France: contact Denis Gapais, ISAG 96, Geosciences Rennes, Universite
Rennes 1,
35042 Rennes Cedex, France; fax 33-99-28-61-00; email: isag96@seth.univ-
rennes1.fr. Abst. deadline is April 1, 1996; official languages are
French, English, and
Spanish.
Oct. 9-13: Exhumation processes: normal faulting, ductile flow, and
erosion (international
GSA Penrose Conference): Orthodox Academy of Greece, Crete, Greece;
contact M.
T. Brandon, Dept. of Geology and Geophysics, Yale Univ, P.O. Box 208109,
New
Haven, CT 065d20-8109; phone (203) 432-3135; fax (203) 432-3134; email:
mark.brandon@yale.edu
Oct. 18-20: Geological correlation of ophiolites and volcanic arcs
in the circum-Caribbean
region (IGCP Project 364) : Cuba; contact Grenville Draper, Dept. of
Geology, Florida
International Univ., Miami, FL 33199; phone (305) 348-3087; fax (305)
348-3877;
email: drapr@servax.fiu.edu
1997
March 5-6: Continental transpressional and transtensional tectonics
(international meeting):
London, U.K.; contact R. Holdworth, Dept. of Geol. Sciences, Univ.
of Durham,
Durham DH1 3LE, U.K.; fax 0191 374 2510; email: R.E.Holdsworth@durham.ac.uk.
A forum for discussion of recent advances in modern and ancient continental
transtensional and transpressional zones. Abst. deadline: Sept. 30,
1996; papers:
March 6, 1997.