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CARNEGIE INSTITUTION Annual Report of the Director Geophysical Laboratory 5251 BROAD BRANCHROAD,NORTHWEST,WASHINGTON,D.C. 20015-1305 1990-1991 FortheyearJuly 1, 1990-June 30, 1991 IssuedDecember 1991 Papersfrom theGeophysicalLaboratory CarnegieInstitution ofWashington NO. 2250 Digitized by the Internet Archive in 2012 with funding from LYRASIS Members and Sloan Foundation http://www.archive.org/details/annualreportofd199091carn Geophysical Laboratory Washington, District ofColumbia Charles T. Prewitt Director Published by: Geophysical Laboratory 5251 Broad Branch Rd., N.W. Washington, D.C., 20015-1305 USA ISSN 0576-792X December 1991 When used in bibliographic citations, The Annual Report should be cited as follows: Author, Title, Annu. Rep. Director Geophys. Lab., Carnegie Instn. Washington, 1990-1991, pagina- tion, 1991. - GEOPHYSICAL LABORATORY Contents Introduction 1 Akermanite-Gehlenite-Sodium Melilite Join at 950 C and 5 kbar in the Presence of CO2 + — Igneous and Metamorphic Petrology H2O. H.G. Huckenholz, H.S. Yoder, Jr., T. Field Studies 3 Kunzmann, and W. Seiberl 75 Merwinite StabilityandHigh-TemperaturePhase Global Convection and Hawaiian Upper Mantle Relations inthePresenceofCO2+H2O.H. G. Structures. T.NeilIrvine 3 Huckenholz, H. S. Yoder, Jr., Megacrystalline Dunites and Peridotites: Hosts and W. Seiberl 81 for Siberian Diamonds. N. P. Pokhilenko, D. The System Mg2Si04-Fe2SiC>4 at Low Pressure. G. Pearson F. R. Boyd, HirokoNagahara, Ikuo Kushiro, , andN.V.Sobolev 11 andBjorn O. Mysen 88 Mantle Metasomatism: Evidence froma MARID Fe3+, Mg order-disorder in heated MgFe204: a - Harzburgite Compound Xenolith. powderxrdand 57pe mossbauerstudy. H. St. F.R.Boyd 18 C. O'Neill, H. Annersten andD. Virgo ....93 Boron and Beryllium Concentrations in Subduc- tion-Related Metamorphic Rocks of the Crystallography - Mineral Physics 101 Catalina Schist: Implications forSubduction- Zone Recycling. Gray E. Bebout, Jeffrey G. PredictedHigh-Pressure Mineral Structures with Ryan, and William P. Leeman 23 OctahedralSilicon.RobertM.HazenandLarry Laser Fluorination of Sulfide Minerals with F2 W. Finger 101 Gas. D. Rumble, J. M. Palin, SimultanousHighP-TDiffractionMeasurements andT. C. Hoering 30 of (Fe,Mg)Si03-Perovskite and (Fe,Mg)0 Stable Isotope and Trace Element Indicators of Magnesiowiistite: Implications for Lower Devolatilization History in Metashales and MantleComposition.YingweiFei,Ho-Kwang Metasandstones. Gray E. Bebout 34 Mao, RussellJ. Hemley, andJinfu Shu ..107 The Fa Content ofNormative ol. High-Pressure Crystal Chemistry of Iron-Free Felix Chayes 40 Wadsleyite, p-Mg2SiC>4Jinmin Zhang, Rob- — ertM. Hazen, andJaidong Ko 115 Igneous and Metamorphic Petrology Phase Transitions in Framework Minerals. Experimental Studies 45 DavidPalmer 120 First-prirciples Studies of Elasticity and Post- Raman Spectra of High-Temperature Silicate Stishovite Phase Transitions in Si02. Melts:Na20-Si02,K20-SiC>2,andLi20-SiC>2 RonaldE. Cohen 126 Binary Compositions. John D. Frantz and Molecular Dynamics Simulations of Melting of Bjorn O. Mysen 45 MgO at High Pressures. Zhaoxin Gong, Peralkalinity and H2O Solubility Mechanisms in RonaldE. Cohen, andLarryL. Boyer ... 129 Silicate melts, Bjorn Mysen 53 Glass Diffraction Measurements with Polychro- Partitioningoffluorineandchlorinebetween apa- matic Synchrotron Radiation. CharlesMeade titeandnon-silicatefluidsathighpressureand andRussellJ Hemley 135 . temperature. James Brenan 61 X-RayDiffractionofSolidNitrogen-HeliumMix- InvestigationofFluidImmiscibilityinthe System tures. WillemL. Vos, Larry W. Finger, H20-NaCl-CC>2UsingMassSpectrometryand RussellJ. Hemley, Ho-Kwang Mao, Microthermometry Techniques Applied to Jing Zhu Hu, Jin Fu Shu, Richard LeSar, Synthetic Fluid Inclusions. Andre de Kuijper, RobertK. Popp,John D. Frantz, andJanA. Schouten 138 andThomas C. Hoering 68 CARNEGIE INSTITUTION EvidenceforOrientationalOrderingofSolidDeu- Rapid Racemization ofAspartic Acidin Mollusk terium at High Pressures. RussellJ. Hemley and Ostrich Eggshells: A New Method for andHo-Kwang Mao 141 Dating on a Decadal Time Scale. Glenn A. Goodfriend, David W. von Endt, BlOGEOCHEMlSTRY 147 andP.E. Hare 172 A Burning Question: Differences between Labo- NitrogenIsotopeTracersofAtmosphericDeposi- ratory-InducedandNaturalDiagenesis inOs- tion in Coastal Shelf Waters off North Caro- trichEggshellProteins.AS.Brooks,P.E.Hare, lina. J.E. Kokis andK. Durana 176 Marilyn L. Fogel andHans W. Paerl 147 NitrogenDiagenesisinAnoxicMarineSediments: Publications 181 Isotope Effects. David J. Velinsky, David J. Burdige, andMarilyn L. Fogel 154 Personnel 185 The Isotopic Ecology of Plants and Animals in AmboseliNationalPark,Kenya.PaulL.Koch, Anna K. Behrensmeyer, andMarilyn L. Fogel 163 GEOPHYSICAL LABORATORY Introduction Last year's introduction to the Annual ment of Geological and Geophysical Sci- GL Report described the co-location of the ences at Princeton. staff members Geophysical Laboratory and the Depart- involvedwiththeCenterare Francis Boyd, ment ofTerrestrial Magnetism in our new RonaldCohen.LarryFinger,RobertHazen, andnewly-renovated building complex on Ho-kwang Mao, Russell Hemley, Bjom Broad Branch Road. This year the con- Mysen, Charles Prewitt, and David Virgo. struction and renovation were completed In addition to the above institutions, col- and both departments are pursuing their laboration is being developed between the normal research objectives with almost all Center and other laboratories in universi- of our equipment operating as it should. ties, industry, andgovernment. Theprinci- Moving and the relocation oflaboratories palgoaloftheCenteristo studyfundamen- has been disruptive for many staff mem- tal questions about the Earth's evolution, bers, but we all believe that the new envi- structure, and dynamic state, and about the ronment and proximity to colleagues at nature ofinteriors ofotherplanets. Inaddi- DTM are worth the effort. tion, we expect to generate extensive new The principal new research initiative information about material properties at forthe GeophysicalLaboratory this yearis high pressures and temperatures, and to our participation in the new Center for synthesizenewmaterialsofinteresttophys- High Pressure Research with the State ics, chemistry, and materials science as University of New York at Stony Brook wellas to the earth sciences. Experimental andPrincetonUniversity. This isoneofthe work will be complemented by theoretical 14 Centers established in 1991 through computer simulations andby development funding by the NSF Science and Technol- ofnewequipmentandtechniques forhigh- ogy Center Program. Depending on Con- pressureresearch, includinglarger-volume gressional budgetary approvals, NSF in- experimental apparatus. tends to continue the Program for at least Systematic high-pressure work on ma- four more years, and it is possible that terials of geological interest has been a funding could extend for a total of eleven fundamental component of Geophysical years. The funds suppliedby NSFtogether Laboratory activities since 1904 and GL with contributions from the three institu- staff have played the major role in the tions and additional external grants will be development andutilizationofmany types used to support a variety of initiatives re- ofhigh-pressure apparatus, including pis- lated to high-pressure research. ton-cylinder,cold-seal,gas-media,anddia- TheCenteriscomposedofstaff,students, mond-anvil devices. For example, in re- and laboratories at the Geophysical Labo- cent years Ho-kwang Mao and his col- ratory, the Department ofEarth and Space leagues have led the development and ap- Sciences at Stony Brook, and the Depart- plication of the diamond-anvil cell for ex- CARNEGIE INSTITUTION perimental studies athigh pressure. Static only facility of its type anywhere in the — pressures ofabout5.0megabars substan- World. tially greater than that at the Earth's cen- Another new development this year is — ter havebeenattained,theimportantpres- the installation of a Dilor micro-Raman omMy sure-measuring scale using ruby fluores- systembyJohnFrantzandBj senfor cence has been extended to 1.8 megabars, examining the structures ofsilicate liquids andpressure-scalex-raydiffractionstudies at high temperature. Heretofore, most have been extended above 3 megabars. Raman studies of melts actually involved Techniques have been developed for heat- measurements on glasses quenched from ing samples within the cellby laser and for high temperatures. Investigators were studying them by means of a variety of forced to assume that the glasses were spectroscopic techniques. The establish- representative ofmelts at temperature, but mentofthe Centerwillallowustocontinue there were many doubts about the validity andextendthiskindofinnovationtogreater ofthisassumption. Now,FrantzandMysen extremesofpressureandtemperature,larger have made extensive recordings ofRaman samplevolumes,andexperiments onmany spectra on silicate melts at temperatures as different kinds of materials. high as 1600°C and it appears that they In recent years, Mao, Russell Hemley, have opened up a new and exciting area of and colleagues have have concentrated melt research. much of their work on inert gases that Douglas Rumble, Michael Palin, and crystallize into solid forms at high pres- Thomas Hoeringhave developedamethod sures. Theirexperiments with solidhydro- for laser fluorination of sulfide minerals gen have exceeded 2.5 megabars, where with fluorine gas. This technique allows they discovered new phase transitions and fast andprecise in-situ micro-sampling on the first evidence of transformations into three of the four sulfur isotopes, 32S, 33S, the metallic form. To supportthis research, and 34S, and will provide information on anumberofstaffmembersandpostdoctoral mass transfer in sulfide system on a scale fellows have beenactive indeveloping and that was previously inaccessible. using x-ray and infrared beam lines at the In addition to these initiatives related to National Synchrotron Light Source, a new NSFCenterand to new instrumenta- Brookhaven National Laboratory, for ex- tion, staff members, postdoctoral fellows periments that could not be performed sat- and associates, and visiting investigators isfactorily without the use of synchrotron have been involved in a wide range of radiation. In particular, the superconduct- research, ranging from racemization dating wiggler beam line X17C provides a ing ofostrich shellsto global convection of high-energy beam with very high intensity the uppermantle. Much ofthis research is x-rays for probing tiny samples in dia- described inbriefsummariesinthisAnnual mond-anvil cells. The infrared beam line Report, thus continuing the Geophysical U4 provides high-intensity infrared radia- Laboratory tradition of early communica- tion for spectroscopic measurements of tion of results before full papers are pub- samples in diamond-anvil cells, and is the lished in scientific journals. ) GEOPHYSICAL LABORATORY Igneous and Metamorphic Petrology Field studies Global Convection and Hawaiian Upper completelyconsistenteither(e.g.,seecom- Mantle Structure parisonsmadebyRomanowicz, 1991),but a set by Inoue et al. (1990) is especially interesting because the maps areunusually T. Neil Irvine detailed. Much of the detail correlates meaningfully with surface geological fea- This report gives further development tures (particularly volcanic hotspots), so of the global convection system proposed the data appear significant. Some features by Irvine (1989). In this system, upper are notably compatible with the mantle mantle convection is stratified at both the convection relationships favored here.1 400- and the 670-km seismic The Inoue et al. (1990) maps fornomi- discontinuities, and the lower mantle fea- nal depths of 478-629 km and 1203-1435 tures an orthogonal framework ofsix prin- km are illustrated in Fig. 1, together with a cipal convection centers, or axes where mapbyWoodhouseandDziewonski(1989) upwelling occursbeneathIceland, Hawaii, for 150 km. The relations for 1203-1435 the Balleny Islands (near Antarctica), and km warrantparticularattentionbecause the Okavango delta (in Botswana), and (1 they are dominated by two major zones of downwelling beneath Peru and the eastern low velocity, one under Hawaii, the other edge of Vietnam. In last year's Report beneath Okavango, and (2) the extensions (Irvine, Annual Report 1989-1990, p. 3- of these two zones in combination with 11), the concept ofan uppermantle vortex several small, low-velocity anomalies, en- supercell was introduced for the Iceland compassmostofthe world'shotspots. The centerandexplored on thebasis ofseismic twomajoranomalies arebothprominentin data. Application of this concept is now several earlier tomographic maps (e.g., extended to the Hawaiian center. Giardini etal, 1987), but the velocity data in these cases were smoothed to low-order spherical harmonics, so the anomalies are Mantle Tomography andHotspots onlybroadly delimited. The anomaly loca- Whenthe above global-convectionsys- 1 In interpretations ofmantle tomography here it tem was proposed, some support was cited is assumed simply that seismically slow regions arerelativelywarmand,thus,mayrepresentzones from seismic tomography, but the ofconvective upwelling, whereas fastregions are tomographicmapsthenavailableportrayed cooler and, therefore, may reflect downwelling. Compositional andphase differences and seismic only broad features and frequently seemed anisotropy are likely to be complicating factors incompatible. More recent maps are not but cannot be considered here. CARNEGIE INSTITUTION 150 km ++++ %§ Woodhouse and Dziewonski, 1989 ++++ ++++ Model U84L85/SH =1-8 ++++ Z -3% 3% 478-629km Inoue et al.,1990 :::::+±±±X ++++++++++++ 'V//K// i ++++ 2%