Subduction Top to Bottom

386 Pages·1996·36.518 MB·English

by  Gray E. Bebout, David W. Scholl, Stephen H. Kirby, John P. Platt

Geophysical Monograph Series
Including
IUGG Volumes
Maurice Ewing Volumes
Mineral Physics
GEOPHYSICAL MONOGRAPH SERIES
GeophysicalM onographV olumes 22 DerivationM, eaning,a nd Use of Geomagnetic
Indices P. N. Mayaud
1 Antarcticai n the International Geophysical 23 The Tectonica nd GeologicE volutiono f Southeast
Year A. P. Crary,L . M. Gould,E . O. Hulburt, AsianS easa nd Islands DennisE . Hayes(E d.)
HughO dishawa,n dW aldoE . Smith( Eds.) 24 Mechanical Behavior of Crustal Rocks: The Handin
2 Geophysicsa nd the IGY Hugh Odishawa nd Volume N. L. CarterM, . FriedmaJn.,M . Logana,n d
StanleyR uttenber(gE ds.) D. W. Steams( Eds.)
3 AtmosphericC hemistryo f Chlorine and Sulfur 25 Physicso f AuroralA rc Formation S.-I.A kasofaun d
Compounds JamesP . LodgeJ, r. (Ed.) J.R . Kan (Eds.)
4 ContemporaryG eodesy CharlesA . Whittena nd 26 HeterogeneouAst mospheriCc hemistry
Kenneth H. Drummond (Eds.) DavidR . Schrye(rE d.)
5 Physicso f Precipitation HelmutW eickman(nE d.) 27 The Tectonica nd GeologicE volutiono f Southeast
6 The Crust of the Pacific Basin AsianS easa nd IslandsP: art2 DennisE . Hayes(E d.)
Gordon A. Macdonald and Hisashi Kuno (Eds.) 28 MagnetospherCicu rrents ?(cid:127) A. Potemr(aE d.)
7 Antarctic Research: The Matthew Fontaine 29 ClimateP rocesseasn d ClimateS ensitivity
Maury Memorial Symposium H. WexlerM, . J. (MauriceE wingV olume5 ) JameEs. Hansenan d
Rubin,a ndJ . E. CaskeyJ,r . (Eds.) Taro Takahash(iE ds.)
8 Terrestrial Heat Flow William H. K. Lee (Ed.) :30M agneticR econnectioinn Spacea nd Laboratory
9 Gravity Anomalies:U nsurveyedA reas Hyman Plasmas EdwardW . HonesJ, 7:( Ed.)
Orlin (Ed.) 31 PointD efectsin Minerals( MineralP hysics
10 The Earth Beneath the Continents: A Volume of Volume 1) RobertN . Schock(E d.)
GeophysicalS tudiesi n Honor of Merle A. 52 The CarbonC yclea nd AtmosphericC O2:N atural
Tuve JohnS . Steinharat nd T. JeffersoSnm ith( Eds.) VariationsA rcheanto Present E.T. Sundquiasnt d
11 Isotope Techniques in the Hydrologic Cycle W. S. Broecker(E ds.)
Glenn E. Stout (Ed.) 33 GreenlandIc e Core(cid:127)G. eophysicsG, eochemistry,
12 The Crust and Upper Mantle of the PacificA rea and the Environment C. C. LangwayJ,r .,
LeonK nopo(cid:127),C harlesL . Drake,a nd H. Oeschgearn,d W . Dansgaa(rEdd s.)
PembrokeJ . Hart (Eds.) 34 CollisionlessS hocksin the HeliosphereA: Tutorial
13 The Earth's Crust and Upper Mantle Review RobertG . Stonea nd Bruce T. Tsurutani (Eds.)
PembrokeJ . Hart (Ed.) 35 CollisionlesSs hocksin the HeliosphereR:.e viewso f
14 The Structurea nd PhysicalP ropertieso f the Current Research Bruce T. 7(cid:127)urutani and
Earth's Crust JohnG . Heacock( Ed.) RobertG . Stone( Eds.)
15 The Use of Artificial Satellitesf or Geodesy (cid:127) 6 Mineral and RockD eformationL: aboratoryS tudies
Soren W. Henricksen,A rmando Mancini, and --The Paterson Volume B. œ.H obbs and
Bernard H. Chovitz (Eds.) H. C. Heard (Eds.)
16 Flow and Fracture of Rocks H.C. Heard, 37 EarthquakeS ourceM echanics(M auriceE wing
L Y. Borg,N . L. Carter,a ndC . B. Raleigh(E ds.) Volume6 ) ShamitDaa sJ, ohnB oatum(cid:127)hatn, d
17 Man-Made Lakes: Their Problems and ChristophHe. rS chol(zE ds.)
Environmental Effects William C. Ackermann, (cid:127)8 Ion Acceleratioinn the Magnetospheraen d
GilbertF . White,a nd E. B. Worthington(E ds.) IonosphereT ornC hang(E d.)
18 The Upper Atmospherei n Motion: A Selection 39 High PressurRe esearchin Mineral Physics
of PapersW ith Annotation C.O. Hinesa nd (MineralP hysicsV olume2 ) Murli H. Manghnanain d
Colleagues YasuhikSoy ono(E ds.)
19 The Geophysicso f the PacificO ceanB asina nd 40 GondwanaS ix:S tructureT, ectonicsa, nd Geophysics
Its Margin: A Volume in Honor of George P. GaryD . McKenzi(eE d.)
Woollard GeorgHe . SuttonM, urli H. Manghnani, 41 GondwanaS ix:S tratigraphyS,e dimentologya,n d
andR alphM oberly( Eds.) PaleontologyG arryD . McKenzi(eE d.)
20 The Earth's Crust: Its Nature and Physical 42 Flow and TransporTt hroughU nsaturatedF ractured
Properties JohnC . Heacoc(kE d.) Rock DanielD . Evansa nd ThomaJs. Nicholson(E ds.)
21 Quantitative Modeling of Magnetospheric 43 SeamountsIs, landsa, ndA tolls BarbarHa. Keating,
Processes W. P. Olson (Ed.) PatffciFar yerR, txteBy atizaa,n dG eorgWe . Boehlert
44 ModelingM agnetospherPicl asma T. E. Moorea ndJ . 67 High-PressurRe esearchA: pplicationt o Eartha nd
H. Waite,J r. (Eds.) PlanetaryS cience(sM ineralP hysicsV olume 3)
45 Perovskite: A Structure of Great Interest to YasuhikSoy onaon dM urli H. Manghnan(Ei ds.)
Geophysicasn d MaterialsS cience 68 MicrowaveR emoteS ensingo f SeaI ce
AlexandrNaa vrotskayn dD onaldJ . Weidne(rE ds.) FrankC arseyR,o geBr arryJ, osefinCoo misoD,. Andrew
46 Structurea nd Dynamicso f Earth'sD eep Interior RothrocRko, berSt huchmaWn,. TerryT uckerW, ilford
(IUGG Volume 1) D. E. Smyliea nd Weeksa, nd Dale Winebrenner
RaymonHdi de( Eds.) 69 SeaL evelC hangesD: eterminationa nd Effects
47 HydrologicaRl egimesa nd Their Subsurface (IUGG Volume1 1) P. L. WoodwortDh., T. Pugh,
Thermal Effects( IUGG Volume 2) Alan E. Beck, J. G. DeRondeR, . G. Warricka, ndJ . Hannah
GrantG aroena,n dL ajosS tegen(aE ds.) 70 Synthesios f Resultsfr om ScientificD rilling in the
48 Origin and Evolutiono f SedimentarBy asins Indian Ocean RobertA . Duncan,D avid K. Rea,
and Their Energya nd Mineral Resources RoberBt . Kidd,U lrichv onR ad,a ndJ effreKy. Weisse(El ds.)
(IUGG Volume3 ) RaymonAd. Price(E d.) 71 Manfie Flow and Melt Generation at Mid-Ocean
49 Slow Deformation and Transmission of Stress
Ridges JasoPnh ippMs organD, onnaK . Blackman,
in the Earth (IUGG Volume 4) StevenC . Cohena nd andJ ohnM . Sinton( Eds.)
Petr Vanf(cid:127)ek (Eds.)
72 Dynamicso f Earth'sD eepI nteriora nd Earth
50 Deep Structurea nd PastK inematicso f Accreted
Rotation (IUGG Volume 12) Jean-LouLise Mou(cid:127)l, D.E.
Terranes( IUGG Volume 5) JohnW . Hillhous(eE d.)
Smyliea,n dT homaHse rring(E ds.)
51 Propertiesa nd Processeosf Earth'sL owerC rust
73 EnvironmentaEl ffectso n SpacecrafPt ositioninga nd
(IUGG Volume6 ) RoberFt. MereuS, tephaMnu eller,
Trajectorie(sI UGG Volume 13)
and David M. Fountain (Eds.)
A. Vallanc]eo nes(E d.)
52 UnderstandingC limateC hange( IUGG Volume7 )
74 Evolution of the Earth and Planets (IUGG
AndreL . BergeRr, oberEt . Dickinsoann, dJ .K idson(E ds.)
Volume1 4) E. TakahasRhia, ymonJde anloazn, d
53 Plasma Waves and Instabilities at Comets and in
David Rubie (Eds.)
MagnetospheresB ruceT . Tsurutanani dH iroshOi ya
75 InteractionBs etweenG lobalC limateS ubsystems:
(Eds.)
The Legacyo f Hann (IUGG Volume 15)
54 SolarS ystemP lasmaP hysics J.H. WaiteJ, r.,
G. A. McBean and M. Hantel (Eds.)
J.L . Burcha, ndR . L. Moore( Eds.)
76 RelatingG eophysicaSl tructureasn d ProcesseTsh: e
55 Aspectso f ClimateV ariabilityi n the Pacifica nd
JeffreyVs olume( IUGG Volume1 6) K. A/a'a nd
Western Americas David H. Peterson( Ed.)
R. Dmowska( Eds.)
56 The Brittle-Ductile Transition in Rocks A.G. Duba,
77 The MesozoicP acificG: eologyT, ectonicsa,n d
W. B. DurhamJ, .W . Handina, ndH . F. Wang( Eds.)
Volcanism--AV olumei n Memoryo f Sy Schlanger
57 Evolutiono f Mid OceanR idges( IUGG Volume8 )
MalcolmS .P ringleW, illiamW . SagerW, illiamV . Sliter,
JohnM . Sinton( Ed.)
and SethS tein (Eds.)
58 Physicso f MagneticF lux Ropes C T. Russall,
78 ClimateC hangei n ContinentaIls otopicR ecords
E. R. Priest,a nd L. C. Lee( Eds.)
P. K. Swart,K . C. LohmannJ,. M cKenziea, nd S. Savin
59 Variations in Earth Rotation (IUGG Volume 9)
(Eds.)
DennisD . McCarthya ndW illiamsE . Carter(E ds.)
79 The Tornado:I ts StructureD, ynamicsP, redictiona, nd
60 Quo Vadimus Geophysicfso r the Next Generation
Hazards C ChurchD, . BurgesCs,. Doswell,
(IUGG Volume1 0) GeorgDe. Garlanadn d
R. Davies-Jon(eEsd s.)
JohnR . Apel( Eds.)
61 CometaryP lasmaP rocesseAsl anD . Johnsto(nEed .) 80 AuroralP lasmaD ynamics R. L. Lysak(E d.)
62 Modeling MagnetospheriPcl asmaP rocesses 81 SolarW ind Sourceso f MagNetospheriUcl tra-Low
GordonR . Wilson (Ed.) FrequencWy aves M. J.E (cid:127)zgebretsKo.n T, akahasahni,d
63 Marine ParticlesA: nalysisa nd Characterization M. Scholer( Eds.)
DavidC . Hurda ndD erekW . Spence(Er ds.) 82 Gravimetrya nd SpaceT echniquesA pplied to
64 MagnetospheriScu bstormsJ osepRh. Kan, Geodynamicsa nd OceanD ynamics( IUGG Volume
ThomasA . PotemraS, usumuK okubuna, nd 17) BobE . SchutzA, llen AntlersonC, laudeF roidevaux,
TakesIiij ima( Eds.) and Michael Parke (Eds.)
65 ExplosionS ourceP henomenologyS teveRn . Taylor, 83 NonlinearD ynamicsa nd Predictabilityo f
HowardJ . Pattona, ndP aulG . Richard(sE ds.) GeophysicaPl henomena(I UGG Volume 18) William
66 Venusa nd Mars:A tmospheresIo, nospheresa,n d I. Neum(cid:127)n, Andrei Gabrielova, nd DonaldL . Turcotte( Eds.)
Solar Wind Interactions JanetG . LuhmannM, ariella 84 SolarS ystemP lasmasin Spacea nd Time J.B urchJ, .
Tatrallyaya,n dR oberOt . Pepin(E ds.) H. Waite,J r.
85 The PolarO ceansa ndT heirR olei n Shapingth e 2 HydrologicaRl egimesa nd Their Subsurface
Global Environment ¸. M. JohannessRe.n D, . Muench, Thermal Effects Alan E. BeckG, rantG arvena, nd
andf . E. (Zerland (Eds.) LajosS tegen(aE ds.)
86 SpaceP lasmasC: ouplingB etweenS malla nd 3 Origina ndE volutioonf SedimentarBya sinsa nd
Medium ScaleP rocesses MahaA shour-AbdallTao, m Their Energya nd Mineral Resources
Changa,n dP aulD usenbe(rEyd s.) RaymonAd. Price( Ed.)
87 The UpperM esospheraen dL owerT hermospherA(cid:127). 4 Slow Deformation and Transmission of Stress
Reviewo f Experimenatn dT heory R. M. Johnsoannd in the Earth StevenC . Cohena ndP etr Vanf(cid:127)ek(E ds.)
T. L. Killeen (Eds.) 5 Deep Structurea nd PastK inematicso f Accreted
88 ActiveM arginsa nd MarginalB asinso f theW estem Terrances JohnW . Hillhouse(E d.)
Pacific BrianT ayloar ndJ ameNsa tland(E ds.) 6 Propertiesa nd Processeosf Earth'sL ower Crust
89 Naturala nd AnthropogeniIcn fluencesin Fluvial RobeFrt. MereuS, tephaMnu ellera,n dD avidM . Fountain
GeomorphologyJ ohnE . CostaA, ndrewJ .M iller, (Eds.)
KennethW . Potter,a nd PeterR . Wilcock(E ds.) 7 UnderstandiCngli mateC hangeA ndrLe . Berger,
90 Physicosf theM agnetopausPea uSl ongB,. U.((cid:127). RoberEt . Eh'ckinsoannd, J .K idson(E ds.)
Sonneruapn, dM .F. Thomse(nE ds.) 8 Evolutiono f Mid OceanR idges JohnM . Sinton(E d.)
91 SeaflooHr ydrothermaSly stemsP:h ysicaCl, hemical, 9 Variationsin EarthR otation DenniDs . McCarthy
Biologicaal,n d GeologicaIln teractionsS usanE . and William E. Carter (Eds.)
HumphifsR,o berAt . Zierenbertagu, renS .M ullineauaxn, d 10 Quo VadimusG eophysicfso r the Next Generation
RichardE . Thomson( Eds.) GeorgDe. Garlanadn dJ ohnR . Apel( Eds.)
92 Mauna LoaR evealedS: tructureC, omposition, 11 SeaL evelC hangesD: eterminationasn d Effects
History,a nd Hazards J.M . Rhodeasn dJ ohnP . PhilipL . WoodworDthav, idT . PughJ,o hnG .D eRonde,
Lockwood(E ds). RicharGd . Warricka,n dJ ohnH annah(E ds.)
93 Cross-ScaCleo uplingi n SpaceP lasmas JameLs. 12 Dynamicso f Earth'sD eepI nteriora nd EarthR otation
HonvitzN, agendrSai ngha, ndJ ameLs. Burch(E ds.) Jean-LouLiesM ou(cid:127)l,D .E.S myliea,n d
94 Double-DiffusivCeo nvectionA lanB randatn dH .J.S. ThomaHse rring(E ds.)
Fernando (Eds). 13 EnvironmentEaflf ectosn SpacecraPfto sitioninagn d
95 EarthP rocesseRse: adingt he IsotopicC ode As/sh Trajectories A. VallancJeo ne(sE d.)
Basua nd Stan Hart (Eds.) 14 Evolutiono f the Eartha nd Planets E. Takahashi,
RaymonJde anloazn, dD avidR uble( Eds.)
Maurice Ewing Volumes 15 InteractionBse tweenG lobalC limateS ubsystems:
The Legacyo f Hann G.A. McBeanan d
1 IslandA rcs,D eep SeaT renchesa,n dB ack-Arc
M. Hahtel (Eds.)
Basins Manik Talwania nd WalterC . PitmanI II (Eds.)
16 RelatingG eophysicaSlt ructureasn d Processes:
2 Deep Drilling Resultsi n the AtlanticO cean:
The JeffreysV olume K. AJaa' ndR . Dmowsk(aE ds.)
OceanC rust MamTTca twanCi, hristophGe.rH arrison,
17 Gravimetrayn dS paceT echniqueAsp pliedt o
andD enniEs . Hayes(E ds.)
Geedynamicasn dO ceanD ynamics BobE . Schutz,
3 Deep Drilling Resultsin the AtlanticO cean:
AllenA ndersonC, laudeF roidevauaxn, dM ichaePl arke
ContinentaMl arginsa nd Paleoenvironment
(Eds.)
ManikT aIwanWi, illiamH ay,a ndW illiamB .F . Ryan(E ds.)
18 NonlineaDr ynamicasn dP redictabilitoyf
4 EarthquakeP rediction--AnI ntemationalR eview
GeophysicaPl henomena WilliamL NewmanA, ndrei
DavidW . Simpsoann dP aulG . Richard(Es ds.)
Gabrielova,n d DonaldL . Turc(cid:127)tte( Eds.)
5 ClimateP rocessaensd C limateS ensitivity
JamesE . Hansena nd Taro Takahash(iE ds.) MineralP hysicsV olumes
6 EarthquakeS ourceM echanics ShamitDaa sJ, ohn
Boatwrighant,d C hristophHe. rS chol(zE ds.) 1 Point Defectsi n Minerals RoberNt . Schoc(kE d.)
2 HighP ressurRee searcinh MineralP hysics
IUGG Volumes MurliH . Manghnaanni dY asuhikSoy on(aE ds.)
3 High PressurRee searchA:p plicationto Eartha nd
1 Structuraen dD ynamicso f Earth'sD eepI nterior PlanetarSyc iencesY asuhiS(cid:127)oy onaon d
D. E. SmyIiaen dR aymonHdi de( Eds.) Murli H. Manghnani
GeophysicaMl onograph9 6
Subduction
Top to Bottom
Gray E. Bebout
David W. Scholl
Stephen H. Kirby
John P. Platt
Editors
AmericGaeno physical
Publishedu nder the aegiso f the AGU BooksB oard
Cover illustrationb asedo n the gravitym ap "Marine GravityA nomalyF rom SatelliteA ltimetry"
by David T. Sandwell and Walter H. F. Smith.
Library of CongressC ataloging-in-PublicationD ata
Subductionto p to bottom/ Gray E. Bebout. .. [et al.], editors.
p. cm. -- (Geophysicaml onograph; 96)
Includesb ibliographicalr eferences.
ISBN 0-87590-078-X
1. Subductionz ones. I. Bebout,G ray E., 1958-. II. Series.
QE511.46.S83 1996
551.1 ' 36--dc20 96-35932
CIP
ISBN 0-87590-078-X
ISSN 0065-8448
Copyright1 996 by the AmericanG eophysicaUl nion
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Printed in the United States of
CONTENTS
Preface
Gray E. Bebout,D avid IF. Scholl,S tephenH . Kirby, and JohnP . Platt xi
What Goes In
Thermo-mechanicalE volution of Oceanic Lithosphere: Implications for the Subduction
Processa nd Deep Earthquakes (Overview)
Seth Stein and Carol A. Stein 1
GeochemicalF luxes During SeafloorA lteration of the BasalticU pper Oceanic
Crust: DSDP Sites 417 and 418 (Overview)
Hubert Staudigel,T erry Plank, Bill White,a nd Hans-Ulrich Schmincke 19
The First Squeeze
Accretionary MechanicsW ith Properties That Vary in Spacea nd Time (Overview)
DanM. Davis 39
Mountain Building in Taiwan and the Critical Wedge Model
Chi-Yuen Wang,A dam Ellwood, Francis Wu,R uey-JuinR au, and Horng-Yuan Yen 49
Sediment Pore-Fluid Overpressuring and Its Effect on Deformation at the Toe of the Cascadia
Accretionary Prism From SeismicV elocities
Guy R. Cochrane,J . CaseyM oore, and HornaJ . Lee 57
Oblique Strike-Slip Faulting of the Cascadia Submarine Forearc:
The Daisy Bank Fault Zone off Central Oregon
Chris Goldfinger,L aVerne D. Kulm, RobertS . Yeats,C heryl Hummon,G ary J. Hufiile,
Alan R. Niem, and Lisa C. McNeill 65
Fabrics and Veins in the Forearc: A Record of Cyclic Fluid Flow at Depths of < 15 km (Overview)
Donald M. Fisher 75
Large Earthquakes in SubductionZ ones: SegmentI nteraction and RecurrenceT imes (Overview)
Larry J. Ruff 91
What Controls the SeismogenicP late Interface in SubductionZ ones?
Larry J. Ruff and Bart IF. Tichelaar 105
DisplacementP artitioning and Arc-Parallel Extension: Example From the
SoutheasternC aribbean Plate Margin
Hans G. Avd Lallemant 113
The Big Squeeze:B ack From the Pressure Cooker
Thermal and Petrologic Structure of SubductionZ ones (Overview)
Simon M. Peacock 119
Contrasting P-T-t Histories for BlueschistsF rom the Western Baja Terrane and the Aegean:
Effects of SynsubductionE xhumation and Backarc Extension
Suzanne L. Baldwin
CONTENTS
TectoniUc plifta ndE xhumatioonf BlueschiBste ltsA longT ranspressionSatlr ike-SlipF aultZ ones
Paul Mann and Mark B. Gordon 143
Syn-SubductioFno rearcE xtensiona nd BlueschisEt xhumationin Baja California,M 6xico
Richard L. Sedlock 155
Slip-Historyo f the VincentT hrust:R oleo f DenudationD uringS hallowS ubduction
Marty Grove and Oscar M. Lovera 163
A ThermotectonicM odel for Preservationo f Ultrahigh-PressurPe hases
in Metamorphosed Continental Crust
W G. Ernst and Simon M. Peacock 171
VolatileT ransfera ndR ecyclingat ConvergenMt argins:M ass-Balancaen dI nsights
From High-P/T MetamorphicR ocks( Overview)
Gray E. Bebout 179
The Big Squeeze:F rom Beneath the Arc
Intermediate-DepInthtr aslabE arthquakeasn dA rcV olcanismas P hysicaEl xpressionosf C rustaal ndU ppermost
Mantle Metamorphismi n SubductingS labs( Overview)
StephenK irby,E . RobertE ngdahl,a ndR ogerD enlinger 195
SubduetedL ithosphericS labV elocityS tructureO: bservationasn d MineralogicaIln ferences
GeorgeH elfj(cid:127)ich 215
Plate Structure and the Origin of Double SeismicZ ones
Geofj?eyA . Abers 223
PhaseE quilibria Constraintso n Modelso f SubductionZ one Magmatism( Overview)
damesD . Myers and A. Dana dohnston 229
DecipheringM antle and CrustalS ignaturesin SubductionZ oneM agmatism( Overview)
don P. Davidson 251
DescribingC hemicalF luxesi n SubductionZ ones:I nsightsF rom
"Depth-Profiling" Studies of Arc and Forearc Rocks
deffR yan,J ulie Morris, Gray Bebout,a nd Bill Leeman 263
Boron and Other Fluid-Mobile Elements in Volcanic Arc Lavas:
Implications for Subduction Processes
William P. Leeman 269
Effect of Sedimentso n AqueousS ilicaT ransport in SubductionZ ones
Craig E. Manning 277
DoesF ractureZ one SubductionIn creaseS edimentF lux and Mantle Melting in SubductionZ ones?
Trace Element Evidence From Aleutian Arc Basalt
BradleyS . Singer,W illiamP . LeemanM, atthewF . Thirlwalla, ndN icholasW Rogers 285
Experimental Melting of Pelagic Sediment,C onstraintsR elevant to Subduction
Geofj(cid:127)eyT . Nichols,P eterd . Wyllie,a nd CharlesR . Stern
CONTENTS
The Influence of Dehydration and Partial Melting Reactionso n the Seismicity
and Deformation in Warm Subducting Crust
Tracy Rushmet 299
Contrasting Styleso f Mantle MetasomatismA bove SubductionZ ones:
Constraints From U!tramafic Xenoliths in Kamchatka
Pavel Kepezhinskasa nd Marc d. Derant 307
SuprasubductionM ineralization: Metal!o-Tectonic Terranes of the SouthernmostA ndes (Overview)
Eric P. Nelson 315
Hazards and Climatic Impact of Subduction-ZoneV olcanism: A Global and Historical Perspective
Robertl . Tilling 331
The Biggest Squeeze:S lab Structure and Deep-FocusE arthquakes
Eclogite Formation and the Rheology, Buoyancy, Seismicity,a nd H20 Content of Oceanic Crust
BradleyR . Hacker 337
Double SeismicZ ones, CompressionalD eep Trench-Outer Rise Events, and Superplumes
Tetsuzo $eno and Yoshiko Yamanaka 347
Characteristics of Multiple Ruptures During Large Deep-FocusE arthquakes
Wang-PingC hen,L i-Ru Wu,a nd Mary Ann Glennon 357
Imaging Cold Rock at the Baseo f the Mantle: The SometimesF ate of Slabs?( Overview)
Michael E. Wysession
PREFACE
Perhapsn o other plate tectonics ettingh as attracteda s processesb,u t alsob asedo n their demonstrateadb ilitiest o
diversem ultidisciplinarya ttentiona s convergentm argins. considerd iverse observationsin novel multidisciplinary
This has in part been spurredb y the extremelyt angible studies,t hat is, to listen to othersa pproachingth e same
hazardsi mposedb y subductionp, articularlyi n the form of problem from a differentp erspectivea nd using different
earthquakesa nd tsunamisa nd arc volcanism. Concern techniquesT. he choiceo f the SantaC atalinaI slandv enue
regardingt heseh azardsi s heightenedb y the tendencyo f was guided by its locationw ithin a complexlye volving
convergenmt arginst o be heavilyp opulatedc oastarl egions. convergentm argin regime (i.e., largely reflecting Late
There has also been great interest in convergentm argin Cretaceous accretion and Late Tertiary extensional
settingsfo r their potential( and demonstratecda pability)o f processes)O. ur brief field trip to examinee xposureos f the
producinge conomicallyim portanot il andg asr eservoirsa nd CatalinaS chists ubduction-zonme etamorphicc omplexn ot
ore deposits. The cycling of materials (e.g., COO at only serveda s a welcomeb reakf rom the lengthyo ral and
convergentm argins has been recognizeda s potentially posters essionsb, ut alsof ocussedth e groupf urthero n the
significantly effecting changes in our environment,i n complexity of the rock record and the need for multi-
particular, impacting evolution of the hydrospherea nd disciplinaryi nteractiontso copew ith this complexityT. he
atmosphereI.t is widely acceptedt hat convergenmt argin papers in this volume, written mainly by SUBCON
accretiona nd arc magmatismh aveb eenl argelyr esponsible participantsc,o nveyt hem ultidisciplinarsyp irito f SUBCON
for continentacl rustf ormationo ver long periodso f Earth's andw ill key readersto the criticala dditionacl onstrainttsh at
history. are lacking and the most exciting directionsf or future
It is criticalt hatw e be ablet o fathomt he incredibleg lobal researchA. uthorsh avea ttemptedto "puta differents pin"o n
diversityi n the geologicaal nd geophysicael xpressionosf theird iscussionasn dp resentatioonf datat o reflectt he multi-
subductionz ones, a diversity that is incompatiblew ith disciplinarfyl avoro f SUBCON. However,t hesep apersw ill
generic models of plate boundary interactionsi nvolving also stand on their own as fundamental advancements in their
simple thermal, structural, kinematic, or mineralogical respectives ubdisciplinesT.h e papersi n this volume are
approacheasl one.I n our opinion,f urtherp rogressd epends organizedla rgelyb y the depthsth eyc onsideirn an idealized
critically upon improved interdisciplinarys tudieso f the subductionzo ne,b ut the organizationis alsoc onceptuaal nd
subduction process. In this spirit, we organized a reflects in part our biases regarding areas of potential
conference/workshop---SUBCOCNS ubductionF rom Top to researchs ynergy.A s an example,i n the section" The Big
Bottom Conference")(cid:127)to encourageE arth scientistsfr om Squeeze:F rom Beneatht he Arc," papersr angef rom those
diverseb ackgroundsa nd intereststo considers ubductiona s consideringt he geodynamicso f the mantle wedge and
an interactivea nde volutionaryp rocessth atd ependsu pont he slab-mantlei nterface [Helfpich] and the effect on arcs of
prior historyo f lithospherein the oceanb asinsa nd on the varyingt hermale volution[ Kirby et al.] , to thosee xamining
specificc haracteristic(sp ropertiesa nds ettingso) f individual our stateo f knowledgere gardingth e petrologyo f meltingi n
sectors( e.g., depth intervals)o f convergenmt argins.O ur the slaba nd mantlew edge [Myersa nd JohnstonN; icholse t
goal was to bring scientific specialistst o a forum where al.] andt he geochemistroyf arcsr eflectingp rocesseisn the
virtually all earth-scienceo bservationsr elevant to the subductinsgl ab,t hem antlew edge,a ndt heo verlyingo ceanic
progressives tageso f subductiona re consideredf,r om the or continentacl rust[ Ryane t al.; Davidson;L eeman;S inger
surfacea nd shallow subsurfacee nvironmento f the outerr ise, et al.; Kepezhinskaasn d Defant].W e hopet hatt he readers
trencha nda ccretionarwy edget o the mantle'str ansitionz one will examine all papers in these groupingsr ather than
and below where deepe arthquakeso ccura nd slabm elting skippingd irectlyt o the paperi n their specificd iscipline.
and assimilation occur. We have included papers that fall into two format
Participantisn SUBCON (heldi n Avalon,C alifornia,J une categoriesS. omep apersl,a beleda s "Overview"in thet able
1994) were selectedf or the significanceo f their recent of contentsc, ontaina greaterc omponenot f literaturer eview
contributionst o our understandingo f convergentm argin ands ynthesios f recenti nvestigationa, ndt o a greater
xi