The

Newsletter of the Commission on Large-Volume Basaltic Provinces
IA VCEI International Association of Volcanology and Chemistry of the Earth's Interior

The Origin of Large Igneous Provinces symposium at the July IUGG Assembly in Boulder, Colorado, USA is the next major event on the Commission's
agenda. Twenty-five papers are scheduled to be presented in oral and poster
form during the full-day symposium; other symposia will probably also be ofinterest to Commission members (see below for details).
In this issue, recent research on volcanism associated with opening of the
Red Sea, on the crustal structure of the Kerguelen Plateau, and on global
mafic dikes is summarized. A final decision on a publisher for the LIP volume
is imminent. As always, we welcome yotir contributions to The ui Reader,and your recruiting of.interested scientists to join the Commission.

Commission NewsWGG XXI General Assembly
LeaderMike Coffin
Institute for Geophysics
The University of Texas at Austin
8701 North Mopac Expressway
Austin, TX 78759-8397, USA.
Tel: 1S12.471.0429

fax: 1.512.471.8844.

internet:mikec@cof(in.ig.utexas.edu
Secretaryjohn Mahoney
Department o("Geology
and Geophysics
School of Ocean and Earth Scienceand Technology
University of Hawaii
2525 Correa Rd.
Honolulu, HI 96822, USA.
Tel: 1.808.956.8705

fax: 1.808.956.2538
internet:
jmahoney@soest.hawaiLedu
Newsletter Production
Judith Haller and Toni Lee Mitchell

Several symposia relevant to large-volume basaltic provinces are scheduled
for the 1995 IUGG XXI General Assembly in Boulder, Colorado. First andforemost, Origin of lArge Igneous Provinces will be convened by M Coffin, N
Arndt, and J Ludden on 6 July. On 4 July, Evolution of Large Volcanic Systems,
convened by J Pallister, K Hon, J Cole, and M Mantovani, is scheduled. Pallisterand Hon will also lead a field trip the week before IUGG starts to compare themagmatic, structural, and tectonic evolution of large-volume basaltic andrhyolitic volcanic fields through the Columbia River and Yellowstone areas.
Other symposia of interest are (in chronological order): 5 July-Physical andChemical Evolution of the Earth, col)vened by T Ahrens, P Gillet, W McDonough,and E Ohtani; 7 July-Seafloor Volcanism, convened by M Perfit; 10 JulyOrigin and Evolution of the Continental Lithosphere, convened by K Burke, S
Taylor, J Dewey, V Cermak, H Kahle, and T Jordan; 11 July-Geochemical andGeophysical Signatures of Mantle Plumes, convened by W White, L Fleitout, B
Hager, and L Kellogg; 12 July-Mantle Dynamics and the Geological Record,
convened by M Richards, S Cloetingh, G Davies, and M Gurnis. IUGG promises
much in store for students of LIPs!
Volume on Large Igneous Provinces

Both the American Geophysical Union Press and Cambridge University Press
have responded very favorably to our book proposal for a Large Igneous
Provinces volume, and negotiations are entering their fmal stages. · Bothpublishers produce reasonably priced books, so the volume should be affordable to a wide variety of readers. Authors (you know who you are!) should stillplan to submit their papers for review by September: In addition to the papers
already pledged, a chapter on the relation of LIPs to climate change and major
extinctions would be desirable, and potential authors are invited to contact
John Mahoney.

Steering Committee
An updated list of Steering Committee members and their internet addresses follows:

Hans Barsczus (Univ. of Montpellier, France) ................................... barsczus@sajou.dstu.univ-montp2.fr
Ian Campbell (Australian National Univ., Australia) ........................................ ihc1561@huxley.anu.edu.au·· t exas.edu
Mike Coffin (Univ. of Texas,
USA) .......................................................................... mikec@co ff.m.1g.u
Keith Cox (University of Oxford, UK) ............................................................................. trislun@earth.ox.ac.uk
Geoff Davies (Australian National Univ., Australia) ................................,................. geoff@rses.anu.edu.au
Bob Duncan (Oreg~n State Univ., USA ...........................................:............................... rduncan@oce.orst.edu
Jean Goslin (Univ. of Brest, France) .................................................................................... goslin@univ-brest.fr
Chris Harris (Univ. of Cape Town, South Africa) ........................................................... kv@geology.uct.ac.za
Chris Hawkesworth (Open Univ., UK) ...................................................•........................ j.l.dcyden@open.ac.uk
Jim Head (Bro~ Univ., USA) .. .'.............................................................................• head@pggipl.geo.brown.edu
Jan Hertogen (University of Leuven, Belgium) ......................................... jan.hertogen@geo.kuleuven.ac.beJohn Mahoney (Univ. of ~awaii, USA) ................................................................. jmahoney@soest.hawaii.edu
Sverre Planke (Univ. of Oslo, Norway) ............................................................... sverre.planke@geologi.uio.no
Jakob Skogseid (Univ. of Oslo, Norway) .......................................................... jakob.skogseid@geologi.uio.no
Kensaku Tamaki (Univ~ of Tokyo, Japan)·································~~···························... tamaki@ori,u-tokyo.ac.jp
Domillique Weis (Free Un,iv. of Brussels, Belgium) .................................................... dweis@resulb.ulb.ac.be
Dave Williams· (Univ. of Alabama, US~)·:······································································· dwillia3@ua1ix.ua.edu
Full addresses and contact numbers for the above are available over the internet, on diskette, or as
hard copy (see below) from Mike .Coffin.

Recent R~search Summaries
Oligocene Basalt-Rhyolite Flood·VolCanismand Opening of the Red Sea

provided traps for early volcaniclastic deposits
as·sociated with the onset of flood volcanism. The
The. primary objective of our work on thebasal flows yield screened K-Ar dates of 25-31 Ma.
Yemen margin was to establish relationships
Basal volcanostratigraphy is dominated by aamong magmatism, uplift/exhumation, andthick sequence of monotonous basalt overlain byextension. To accomplish this we undertook aan equally thick section·of more diverse litholodetailed study of (a) .t he contact betwe~n the pregies. · The basal basalt series thicke.n s to the south
volcanic sediment. and the basal flows of the flood and west (toward the Red Sea). The upper part ofbasalt-rhyolite province; (b) the volcanostratithe section comprises basaltic flows, rhyolitic fall
graplty .and chronostratigraphy (K-Ar and Ar-Ar)
deposits; and ignimbritic pyroclastic deposits,
along a west-east traverse perpendicular to therare rhyolitic lava flows, and volcaniclastic
Red Sea mar~ and· (c) the 'thermal history of the
secfunentary lenses. Aithough no significant ·margin using fission track dating techniques.
unconformities exist in the main flood basalt pile,i
These data were integrated with studies of thelaterally discontinuous lenses of sedimentary
extensional history by Davison and others (Geol.
material do occur in the succession. At the
Soc. Am. Bull., 1994).
extreme northeastern edge of the province a large
The contact between pre-volcanic sediment and trachytic flow unconformably overlies eroded andthe basal flows shows no evidence for pregently dipping flood basalts. Geochemical analyvolcanic extension~ However radical changes in
ses indicate that most volcanic rocks have experithe paleoenvironment, from one associated withenced some degree of crustal contamination andan ample supply of mature arenites fi:om sourcesthat even highly-magnesian flows contain zoned
in the west to one dominated by sediment starva- · phenocrysts whose core-rim isotopic variations
tion and the widespread development ofcover the total range observed in many of thepaleosols, may indicate widespread pre-volcanic
volcanic products. Ar-Ar age data precisely
surface uplift. Ponding of surface water inestablishes the onset and duration of the pre#"\ topographic lows of this uplifted surface gave rise served volcanic stratigraphy as between 30.4-26.2\!) to fossiliferous lacustrine ~eposits and also
Ma. This 5 m.y. window for flood volcanism is2

much longer than for the Deccan but may compare with that for the Parana-Etendeka. Assuming constant rates of volcanic eruption, it appears
that the basalts were erupted as major flows
every 5-50 ka and that a major ignimbritic
eruption occurred every 200 ka. Interestingly,
the onset of rhyolitic volcanism was accompanied
by intercalated basaltic volcanism and was
associated with a marked decrease in volcanic
production rate, consistent with high-level
development of magma chambers.
In the southern Red Sea and Gulf of Aden,fission track (FT) modeling has revealed a rapid
phase of crustal exhumation which probably
began during the mid- to late Oligocene along thezone of active extension adjacent to the protoRed Sea margin. Significant crustal cooling began
immediately after the subaerial emergence of therift flanks. Furthermore, while exhumation
appears to overlap with a major phase of flood
volcanism ca 29±2 Ma, denudation and cooling
may have waned during this time, only gaining
momentum again during the late OligoceneMiocene when the resistant volcanic cover was
actively extended and rifted. Increasing maturityof drainage patterns on the uplifted landscapeprobably allowed access to the more interior
regions of Yemen by breaching the rift escarpment. Field observations, FT data, and thermal
modeling suggest relatively shallow burial ofpresent basement highs and long-standing
stability as structurally high subsurface features
since the early Mesozoic. Sharp contrasts in FT
data from (elevated) basement highs to (topographically lower) extended coastal terrain-point
to differential movement and exhumation along
inherited (Proterozoic?) structural lineaments in
the Tertiary.
The timing of rift processes in the southern
Red Sea illustrates the complex nature of rift
formation and, in particular, the difficulty inprecisely timing Cloos's (1939) active sequence of
events (uplift-rifting-volcanism) preferred bymany workers or the passive sequence, riftinguplift-volcanism. With these data in hand, we cancomment on the timing of events associated withthe continent rift to oceanic passive margintransition. Although no unequivocal evidence
exists within this area for the timing of surface
uplift, surface uplift must have occurred prior to
30 Ma because (a) pre-volcanic (i.e. pre-32 Ma)
sediment is characterized by the development of
thick paleosol (indicative of sediment starvation
on a low relief landscape) occurring at the top ofa sequence of mature arenites; (b) exhumation(which would presumably postdate surface uplift)
overlaps with, and postdates Oligocene volcanism(40Arf39Ar dates of 32-26 Ma); and (c) extension islargely post-volcanic in age. If these reasons arevalid, the sequence of events is (1) SURFACEUPLIFT: uplift and sediment starvation in the prevolcanic subaerial environment; (2) MAGMATISM:
fissure-fed basaltic volcanism (31 Ma) followed bycaldera-fed rhyolitic and ignimbritic volcanism (ca29 Ma); exhumation in response to surface uplift
may have been reduced during this intense periodof volcanism, hence the lack of interbedded clastic
sediments; (3) EXHUMATION of the rift margins
gains momentum again during the late OligoceneMiocene (ca 26 Ma); (4) EXTENSION in a zone lessthan 100 km across (proto-Red Sea) (ca 26-20 Ma);and (5) MAGMATISM/EXHUMATION: sporadic
post-erosional volcanic activity starting ca 19 Ma
through to the recent activity.
Ongoing studies include (a) an assessment of
the causal link between unroofed magma chambers (syenite-granite-gabbro) and rhyoliticignimbritic eruptives; and (b) an evaluation of thegeochemical consequences of wet melting of the
Arabian lithosphere using naturally melted wet
peridotites from the Ataq diatremes.
contributed by Martin Menzies and members of the
Arabian Plate Research Project-Andrew Yelland,joel Baker and Mohamed Al'Kadasi (Royal
Holloway, University of London, Egham, ·surrey,
England)Deep Structure of the Kerguelen Plateau(Southern Indian Ocean)

Crustal thicknesses .i nferred from wide-angle
seismic data are -23 km in the northern (NKP) andsouthern (SKP) domains of the Cretaceous
Kerguelen Plateau. High seismic velocities at the .
base of the crust (up to 7.4 km/s), however, which
typify the deep structure of oceanic plateaus, areobserved only beneath the NKP. Velocities in thelower crust of the SKP range from 6.6 km/s to 7.0
km/s. Strong anisotropy is observed in the SKP
where multiple reflections from a layered, lowvelocity reflective zone located immediately above
the Moho trend NW-SE, parallel to the strike of theplateau. Along this trend, the upper mantle
velocity is 8.6 km/s, whereas it is only 8.0 km/s inan E-W direction. The results confirm the largescale heterogeneity of the Kerguelen Plateau. The
NKP bears most characteristics of a thickened
oceanic crust, whereas the SKP exhibits the seismic
structure of a thin continental crust. The strong
anisotropy of the reflective lower crust and upper
mantle is consistent with - NW-SE extension.
contributed by Philippe Charvis and Stephane
Operto (ORSTOM-GEMCO, Villefranche-sur-mer,France)<J)

3

The Global Mafic Dike GIS Database Project
We are currently compiling a database of dikeswarms of the world. This database contains
digitized distributions of swarms as well as tablesof properties (geochemical, geochronological,
paleomagnetic, etc.). The purpose of our compilation is to enhance correlation of dikes between
regions and continents, to test paleocontinental
reconstructions and locate mantle paleo-plumes.
More than 300 swarms have been identified
worldwide. Seventy of these have lengths >300
km, with the largest approaching 3000 km.
Individual dikes have been traced up to 1000 km.
However, mapping of lateral flow in the Mackenzie
swarm of the Canadian Shield indicates that
individual dikes can reach lengths >2000 km.
Both linear and radiating swarm types have been
identified. The former are generally associatedwith rift axes. Several of the latter fan over 40°,
reaching a maximum of 180°. Furthermore, more
complete radiating patterns of up to 250° are
observed when coeval swarms are arranged intheir primary radiating pattern in apaleocontinental reconstruction.
Giant dike swarms have important geotectonic

applications. 1) The convergence point offanning swarms is thought to locate mantle
paleo-plumes and associated UPs. 2) Away
from their focal region swarms commonly swing
into the regional stress direction, providing atool for determining the orientation of ancientplate boundaries. 3) Distorted dike swarms canbe used to generate deformation grids for thehost terrane. 4) Reassembly of swarms (fragmented by plate tectonics) into their primarygeometry can help constrain paleocontinental
reconstructions.
Work on the database is continuing and wewelcome input and queries (c/o Richard Emstrernst@gsc.emr.ca)
contributed by Richard Ernstl.Z, Ken Buchanl,and Currie Palmer2 (lGeological Survey ofCanada; 2University of Western Ontario)
Summaries of recent research programs areinvited-please send your contribution to Mike
Coffin or John Mahoney. For the sake of brevity,references are omitted; please contact thecontributors directly for more information

UPs and the Ocean Drilling Program
Each Northern Hemisphere spring, the fourthematic panels of the Joint Oceanographic
Institutions for Deep Earth Sampling (JOIDES)Uthosphere, Tectonics, Ocean History, and Sedimentary & Geochemical Processes-rank all active
ODP proposals. These global rankings, plus
logistical considerations·, form the basis for the
JOIDES Planning Committee's choice of -12
highly-ranked proposals for inclusion in theannual prospectus. Each Northern Hemispherefall, the four thematic panels rank the proposals
in the prospectus. Finally, in December of eachyear, the Planning Committee looks at the
rankings of the proposals in the prospectus anddetermines a rational scientific program for the
JOIDES Resolution one year in advance, i.e., in
December 1995, the program for 1997 will bescheduled.
One large igneous province, the Southeast
Greenland volcanic margin, is scheduled to be
drilled this year during ODP Leg 163 in September
and October. This margin was first drilled by ODP
in 1993 during Leg 152, and the exciting resultsfrom that leg (see "Recent Research Summary" by~ Andy Saunders and the ODP Leg 152 Scientific4Party in The UP Reader #3) contributed strongly
to scheduling another drilling leg there. No largevolume basaltic pro\'inces are on the ODP drilling
schedule for 1996, but UPs fared well in the
Uthosphere Panel's Spring 1995 global rankingsthe Caribbean flood basalt province ranked #2,
the Ontong Java Plateau #3, and the Kerguelen
Plateau/Broken Ridge #4-suggesting that the
Planning Committee may consider scheduling one
or more of these UPs for drilling in 1997. As
described in The LIP Reader #4, formal links
between ODP and our Commission have been
established. Mike Coffin represents our Commission within the ODP advisory structure, as amember of the Uthosphere Panel, and welcomes
input from Commission members.
The Ocean Drilling Program is proposal-driven,and anyone may submit a drilling proposal.
Guidelines for writing and submitting proposals
may be obtained from Rob Kidd or Julie Harris,
JOlDES Office, Dept. of Earth Sciences, Universityof Wales, Cardiff, PO Box 914, Cardiff CFl 3YE,
UK. Telephone 44.222.874.541. Facsimile
44.2'22.874.943. Internet: joid~s@cardiff.ac.uk.
Information on ODP's long-range thematic plans
can be obtained from the same address.

Upcoming Meetings
Synopses of recent meetings are welcomed-please send your -200 word
review to Mike Coffin or john Mahoney.
2 ·14 July: International Union of Geodesy and Geophysics XXI General Assembly, Boulder, Colo·
rado, USA. Information: IUGG XXI General Assembly, c/o American Geophysical Union, 2000
Florida Ave., NW, Washington, DC 20009, USA.
16·21 july: PLUME 2 Conference, Schlo.B Ringberg, Tegernsee, Germany. Abstract deadline: 1 june
1995. Information: Kerstin Lehnert, Max-Planck-lnstitut f\ir Chemie, Postfach 3060, D-S5020
Mainz, Germany. Telephone 49.6131.305260. Facsimile 49.6131.371051. Internet:
kerstin@geobar.mpch·mainz.mpg.de
19 August-1 September: Petrology and Metallogeny of Volcanic and Intrusive Rocks of the
Midcontinent Rift System, Duluth, Minnesota, USA. Abstract deadline: 15 May 1995.
Information: ICGP 336 Conference, Continuing Education & Extension-UMD, 10 University
Drive, 316 DAdB, Duluth, MN 55812-2496. Telephone 1.218.726:6819. Facsimile
1.218. 726.6336. Internet: vfrench@d.umn.edu
4-8 September: Third International Dyke Conference, jerusalem, IsraeL Abstract/pre-registration
deadline: 31 May 1995. Information: Organizing Committee IDC-3 (Dr. A. Heimann), Geological Survey of Israel, 30 Malkhe Yisrael St., Jerusalem 95501, Israel. Facsimile
972.2.380688. Internet: dikeconf@vms.gsi.gpv.il
10-14 October: Sth International Conference on Paleoceanography, Halifax, Nova Scotia, <;anada.
Abstract deadline: 15 june 1995. Information: Larry Mayer, Ocean Mapping Group, Dept. of
Geodesy & Geomatics Engineering, University of New Brunswick. Fredericton, NB, Canada
E3B 5A3. Telephone 1.605.453.4698. Facsimile 1.506.453.4943. Internet:
icpv@predator.ocean.dal.ca .
6-9 November: Geological Society of America Annual Meeting, New Orleans, Louisiana, USA
Abstract deadline: 12 july 1995. Information: GSA Meetings Department, 3300 Penrose .
Place, PO-Box 9140, Boulder, Colorado 80301-9140, USA" Telephone _1.303.447.2020 ext.
141. Facsimile 1.303.447.0648. Internet: mball@geosociety.org
11-15 December: American Geophysical Union Fall Meeting, San Frandsco, California, USA. Abstract deadline: September 1995. Information: AGU Meetings Dept., 2000 Florida Ave.,
Washington, D.C., USA Telephone 1.202.462.6900. Facsimile: 1.202.238.0566. Internet:
meetinginfo@kosmos.agu.org
1996

13-26 February: 13th Australian Geological Convention and Celebration of jubilee of BMR/AGSO,
Canberra, Australia. Information: M.j. Rickard, Secretary, 13th AGC, ACTS, GPO Box 2200,
Canberra, ACT 2601, Australia. Telephone 61.6.249.2056. Facsimile: 61.6.249.5544
20-22 February: Tectonic, Magmatic, and Depositional Processes at Passive Continental Margins,
Burlington House, London, United Kingdom. Information: Nick Kusznir, Dept. of Earth
Sciences, University of Liverpool, Liverpool L69 3BX. United Kingdom.
11·21 july: Long Lava Flow Workshop, Townsville, Australia. Information: P.j. Stephenson, Dept. ofEarth Sciences, james Cook University, Townsville 4811, Australia. Telephone:~
61.77.81.5061. Facsimile: 61.77.25.1501. Internet: jon.stephenson@jcu.edu.au

5Commission Products and Services
UPs on Internet
The LIPS Gopher seiVer is undergoingseveral changes. The seiVer has a new address;
the new Uniform Resource Locator (URL) is

available over the Internet; as well as the calendar of events and teXt versions of The UP
Reader.
As an experiment, The UP Reader will begopher://gopher.ig.utexas.edu:?0/11/res/lips/
made available in Portable Document Format(PDF) as well. The PDF format enables anyone
The old URL will continue to work for several
with Adobe Acrobat Reader software to view The
UP Reader online with all ~ormatting intact. The
more months, but only for Gopher and World
Adobe Acrobat Reader software is available as
Wide Web browsers. The ftp service will be
reenabled at the new URL as soon as possible.
freeware for Macintosh, DOS, or UNIX platforms.
Many browsing programs can be configured to
The LIPS 'files will be relocated to a machine at· launch Acrobat Reader when a PDF file is sethe Institute for Geophysics, so we can havebett~r control over the search engine. We apololected A pointer to the software will be included on the gopher server.
gize to those who have encountered trouble with·the existing setup.
~deas on how the site could be improved are. : The Commission's LIPs ·bibliography of ...,1800 · most welCome. ·For copies of materials onreferences, the directory.of -200 members, and a Macintosh or DOS diskette, please send a blank,
digital database of LIP areas (Figure 1 of Coffin & formatted 3.5 inch diskette to Mike Coffin.
Eldholm, Reviews of Geophysics, 1994) areThe

LIP Reader
Institute (or Geophysics
8701 N. Mopac Expressway
Austin, Texas 78759-8397 USA