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QuarterlyThe IRM

The Eighth Santa Fe Conference on Rock Magnetism was held from June 24-27 at St. John’s College in Santa Fe, New Mexico. Approximately 50 participants from 10 countries convened for a series of lively, in-depth dis-cussions on current topics in rock magnetism and related disciplines. The meeting was made possible through fund-ing from the National Science Foundation, Earth Science Division. Additional conference support was provided by ASC Scientific, Bartington Instruments, Princeton Measurements Corporation, and Quantum Design. Prior to the meeting, John Geissman (University of New Mexico) led the first ever meeting field trip to Valles Caldera National Preserve. Thanks to John’s generosity and hard work in proposing, planning and leading the trip, we spent several pleasurable hours near Jaramillo Creek at the famous paleomagnetic site that gave the Jaramillo subchron its name [Doell and Dalrymple, 1966]. Although subsequent work has demonstrated that this site actually documents a later event [Singer and Brown, 2002], the Jaramillo creek locality helped lead to the widespread acceptance of the Vine-Matthews-Morley hypothesis of seafloor spreading. The meeting officially kicked off later that evening, with the first of two keynote lectures, this one by Peter Olson (Johns Hopkins University). The keynote lectures are meant to provide transdisciplinary perspectives and are

Spring 2010, Vol. 20 No. 2

Julie Bowles, IRM

cont’d. on pg. 6...

The Eighth Santa Fe Conference on Rock Magnetism

Field trip participants pose in front of an outcrop of the Bandolier Tuff. (Photo by Christoph Geiss.)

ISSN: 2152-1972

Inside...Visiting Fellows Reports 2Current Articles 4Visiting Fellows 7

typically given by speakers outside the traditional rock- and paleo-magnetic community. Olson’s well-received talk achieved this goal by addressing recent developments and improvements in dynamo modeling, while point-ing out the important synergies that can be achieved by careful intercomparison of paleomagnetic data and the geodynamo models. Conference participants were able to discuss the lecture and catch up with old friends at a wine reception following the talk. Friday morning commenced with a session on “Suc-cessful Developments in Paleointensity,” convened by Joshua Feinberg (University of Minnesota) and Yohan Guyodo (IMPMC). Talks by Lisa Tauxe (Scripps Institu-tion of Oceanography) and Andrew Roberts (Australian National University) invited participants to be hopeful about the future of paleointensity research, while recog-nizing the current challenges and limitations. In a talk explicitly titled “An optimist’s view of paleointensity,” Tauxe discussed the problems frequently encountered in paleointensity studies and how we can identify and over-come those problems. Roberts focused on sedimentary relative paleointensity, highlighting many important dis-coveries made through this technique; he also pointed out the challenges ahead in achieving better resolution, longer records, a better physical understanding of remanence acquisition processes, and being able to identify and dis-entangle the causes for differences among records. These talks were followed by Jeff Gee (Scripps Institution of Oceanography), who spoke on development of a method

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Visiting Fellow’sReports

Deep continental drilling in the basin of Mexico (central Mexico)

Beatriz OrtegaInstituto de GeofísicaUniversidad Nacional Autónoma de Méxicobortega@geofisica.unam.mx

The Basin of Mexico is a high altitude tropical site (98° 59’ W, 19° 15’ N; 2,250 m asl), that had an extensive lake system sensitive to climatic fluctuations during the past times [1]. A set of four cores up to 120 m depth were collected in the lacustrine sediments of Chalco sub-basin. Radiocarbon dates available from previous works [2,3] on the upper 25 m of lake sediments (20 14C dates), indicate that -- by linear extrapolation -- the 120 m record could cover the last ca. 200-220 kyr. This lacustrine record would provide unique information on Meso-America climate. The sedimentary sequence can give a perspec-tive on long term and millennial scale climate change and its environmental impact in a tropical highland location, information on the variability of the main atmospheric circulation patterns during glacial and interglacial times, and volcanic activity of three of the major stratovolcanoes

Figure 1. Simplified stratigraphy, NRM inclination and preliminary age model for a composite core section 125 m long of Chalco lacustrine sediments. The inclination of GAD value (34.5 °) is indicated in a gray line. Age model is based on 14C dating from upper sediments.

in central Mexico (Popocatepetl, Iztaccihuatl and Nevado de Toluca volcanoes), as well as from the Chichinautzin monogenetic volcanic field around Chalco basin. This record would also provide a regional long term view of the climatic variability, if correlation with sites such as Laguna Salada (Baja California) [4] and Peten Itza (Gua-temala) [5] is possible.

Despite the intense volcanic activity recorded along central Mexico during the Cenozoic, tephra layers account for less than 1 % of the total sedimentary sequence thick-ness. Chronological controls for the upper sequence are certainly established by 14C dating and tephrochronology. However, the intermediate and basic composition of teph-ras makes it difficult to determine a reliable chronology by 40Ar/39Ar dating, and paleomagnetic analyses seems to be a plausible method for dating the sedimentary sequence. Sediment deposition rates recorded in the upper sediments of Chalco basin are 0.5-2.0 mm/yr; the lowest rate gives an average of 52 cm/kyr, which is still high enough for recording paleomagnetic excursions or events [6].

Azimuthally unoriented cores were collected with Shelby barrels and piston Livingston systems in sections one meter long. Cores were split, and then imaging and scanning was performed at the Limnological Research Center (U of M). Sediments are composed of massive brown to gray silt, banded and laminated diatom ooze, and volcaniclastic sediments (Fig. 1). Low field mag-netic susceptibility (MS) was measured along the core halves. U-channels were collected continuously in the sedimentary sequence, except for a section nearly 20 m long between 85 and 105 m depth. NRM of U-channels and AF demagnetization measurements were carried out in an automated 2G u-channel cryogenic magnetometer.

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Low or negative NRM inclination suggests the pres-ence of geomagnetic excursions (Fig. 1). According to the preliminary age model, these “excursions” might correspond to the Laschamp (ca. 41 kyr), Blake (ca. 120 kyr) and Pringle Falls (ca. 220 kyr) events [7].

Sections with anomalous (very low or negative) NRM inclinations were stepwise AF demagnetized in fields from 5 to 170 mT (Fig. 1). At present, only five ca. 1m-sections were AF demagnetized. Directions are mostly stable from 10 to 40 mT (Fig. 2), and the mean destructive field lies below 50 mT.

Several sources of errors may affect the inclination record, from mislabeling of core sections to bioturba-tion, variations due to diagenetic processes affecting the magnetization parameters, smoothing of geomagnetic inclination by compaction, etc. So, very careful analysis and confirmation with parallel core sequences and discrete sample measurements is required before interpreting the presence of geomagnetic excursions.

AF demagnetization of NRM between 0-40 mT in two continuous cores show low and negative inclina-tion centered at 24.65 m depth (Fig. 3). According with our preliminary age-model, this could correspond to the Laschamp Event [8]. The Blake Event [7] might be also recorded, as two parallel cores show negative inclinations at ca. 73 m depth. However, it is still under analysis as discrepancies in stratigraphic correlation and magnetic measurements prevent the unequivocal conformation of its recording in Chalco sediments. The last probable ex-cursion recorded in Chalco sediments is the Pringle Falls Event [9]; however, no AF demagnetization of NRM has been carried out yet of this part of the record.

We plan to continue the paleomagnetic analysis in order to corroborate the record of these geomagnetic excursions, and further continue with the rock magnetic studies in order to investigate the variations of magnetic

Figure 2. AF demagnetization behavior of sample V-39-33 (72.13 m depth), which might correspond to the Blake Event. Zijderveld vectorial diagram, equal-area projection diagram of progressive AF demagnetiza-tion, and coercivity spectra.

mineralogy and their relationship with environmental changes. I want to thank to the staff members of the IRM for their kind assistance and fruitful discussions during this and previous visits.

References[1] Caballero M. and Ortega B. Quat. Res. 50, 69-79, 1988. [2] Lozano-García S., Ortega-Guerrero B., Caballero-Miranda M. and Urrutia-Fucugauchi, J. Quat. Res. 332-342, 1993. [3] Ortega Guerrero B., Thompson R and Urrutia-Fucugauchi. J. Quat. Sci., 15(2), 127-140, 2000. [4] Contreras J, Martín A., Herguera J.C., Cortina A., Rendón G. GEOS 24-2, p. 351, 2004. [5] Hodell D.A., Anselmetti F., Ariztegui D., Brenner M., Curtis J., Gilli A., Grzesik D., Guilderson T., Müller A., Bush M., Correa A., Escobar J. and Kutterolf S. Quat. Sci. Rev. 27, 1152-1165, 2008. [6] Roberts A.P. and Winklhofer M. Earth Plan. Sci Let. 227, 345-359, 2004. [7] Lund S., Stoner J.S., Channell J.E.T., Acton G. Phys. Earth Plan. Int. 156, 194-204, 2006. [8] Bonhommet N. and Babkine J. C.R. Hebs. Seances Acad. Sci. Ser. B. 264, 92-94, 1967. [9] Smith J.D. and Foster J.H. Science 163, 565-567, 1969. [10] Herrero-Bervera E., Helsley C.E., Sarna-Wojcicki A.M., Lajoie K.R., Meyer C.E., McWilliams M.O., Negrini R.M., Turrin B.D., Donnelly-Nolan J.M., Liddicoat J.C. J. Geophys. Res. 99, 24,091-24,103, 1994.

Figure 3. Inclination record versus depth of cores II-14inf and II-15sup (23.70 to 25.70 m depth), which might correspond to the Laschamp Event. Plotted values are 0-40 mT demagnetization steps, and in a gray line the GAD value (34.5 °).

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A list of current research articles dealing with various topics in the physics and chemistry of magnetism is a regular feature of the IRM Quarterly. Articles published in familiar geology and geophysics journals are included; special emphasis is given to current articles from physics, chemistry, and materials-science journals. Most abstracts are taken from INSPEC (© Institution of Electrical En-gineers), Geophysical Abstracts in Press (© American Geophysical Union), and The Earth and Planetary Express (© Elsevier Science Publishers, B.V.), after which they are subjected to Procrustean culling for this newsletter. An extensive reference list of articles (primarily about rock magnetism, the physics and chemistry of magne-tism, and some paleomagnetism) is continually updated at the IRM. This list, with more than 10,000 references, is available free of charge. Your contributions both to the list and to the Abstracts section of the IRM Quarterly are always welcome.

ArcheomagnetismAlva-Valdivia, L.M., J. Morales, A. Goguitchaichvili, M.P. de

Hatch, M.S. Hernandez-Bernal, and F. Mariano-Matias, Ab-solute geomagnetic intensity data from preclassic Guatemalan pottery, Phys. Earth Planet. Int., 180 (1-2), 41-51, 2010.

Hagstrum, J.T., and E. Blinman, Archeomagnetic dating in western North America: An updated reference curve based on paleomagnetic and archeomagnetic data sets, Geochem. Geophys. Geosys., 11, 2010.

Yu, Y., S.J. Doh, W. Kim, Y.H. Park, H.J. Lee, Y. Yim, S.G. Cho, Y.S. Oh, D.S. Lee, H.H. Lee, M.G. Gong, D.H. Hyun, J.K. Cho, Y.S. Sin, and M.S. Do, Archeomagnetic secular variation from Korea: Implication for the occurrence of global archeomagnetic jerks, Earth Planet. Sci. Lett., 294 (1-2), 173-181, 2010.

Current Articles Bio(geo)magnetismLi, J.H., Y.X. Pan, Q.S. Liu, Y.Z. Kui, N. Menguy, R.C. Che, H.F.

Qin, W. Lin, W.F. Wu, N. Petersen, and X.A. Yang, Biominer-alization, crystallography and magnetic properties of bullet-shaped magnetite magnetosomes in giant rod magnetotactic bacteria, Earth Planet. Sci. Lett., 293 (3-4), 368-376, 2010.

Environmental Magnetism and Paleoclimate ProxiesChen, T.H., Q.Q. Xie, H.F. Xu, J. Chen, J.F. Ji, H.Y. Lu, and W.

Balsam, Characteristics and formation mechanism of pedo-genic hematite in Quaternary Chinese loess and paleosols, Catena, 81 (3), 217-225, 2010.

Porsch, K., U. Dippon, M.L. Rijal, E. Appel, and A. Kappler, In-Situ Magnetic Susceptibility Measurements As a Tool to Follow Geomicrobiological Transformation of Fe Minerals, Envir. Sci. Technol., 44 (10), 3846-3852, 2010.

Reynolds, R.L., J.S. Mordecai, J.G. Rosenbaum, M.E. Ketterer, M.K. Walsh, and K.A. Moser, Compositional changes in sedi-ments of subalpine lakes, Uinta Mountains (Utah): evidence for the effects of human activity on atmospheric dust inputs, J. Paleolimnol., 44 (1), 161-175, 2010.

Rijal, M.L., E. Appel, E. Petrovsky, and U. Blaha, Change of magnetic properties due to fluctuations of hydrocarbon con-taminated groundwater in unconsolidated sediments, Environ. Pollut., 158 (5), 1756-1762, 2010.

Symons, D.T.A., K. Kawasaki, and S.J. Pannalal, Paleomagnetic mapping of the regional fluid flow event that mineralized the Upper Mississippi Valley Zn-Pb ore district, Wisconsin, USA, J. Geochem. Explor., 106 (1-3), 188-196, 2010.

Zhang, C.X., Q.S. Liu, B.C. Huang, and Y.L. Su, Magnetic enhancement upon heating of environmentally polluted samples containing haematite and iron, Geophys. J. Int., 181 (3), 1381-1394, 2010.

Extraterrestrial MagnetismBreuer, D., S. Labrosse, and T. Spohn, Thermal Evolution and

Magnetic Field Generation in Terrestrial Planets and Satellites, Space Sci. Rev., 152 (1-4), 449-500, 2010.

Garrick-Bethell, I., and B.P. Weiss, Kamacite blocking tempera-tures and applications to lunar magnetism, Earth Planet. Sci. Lett., 294 (1-2), 1-7, 2010.

Lillis, R.J., M.E. Purucker, J.S. Halekas, K.L. Louzada, S.T. Stewart-Mukhopadhyay, M. Manga, and H.V. Frey, Study of impact demagnetization at Mars using Monte Carlo modeling and multiple altitude data, J. Geophys. Res., 115, 2010.

Ruiz, J., The very early thermal state of Terra Cimmeria: Im-plications for magnetic carriers in the crust of Mars, Icarus, 203 (2), 454-459, 2009.

Weiss, B.P., J. Gattacceca, S. Stanley, P. Rochette, U.R. Chris-tensen, Paleomagnetic Records of Meteorites and Early Plan-etesimal Differentiation, Space Sci. Rev., 152, 341-390, 2010.

Geomagnetism and Geodynamo StudiesAmit, H., and P. Olson, A dynamo cascade interpretation of

the geomagnetic dipole decrease, Geophys. J. Int., 181 (3), 1411-1427, 2010.

Hulot, G., C.C. Finlay, C.G. Constable, N. Olsen, and M. Man-dea, The Magnetic Field of Planet Earth, Space Sci. Rev., 152 (1-4), 159-222, 2010.

Jackson, L.P., and J.E. Mound, Geomagnetic variation on decadal

Diagram of a pivoting compass needle in Peregrinus’s Epistola de Magnete (1269).

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time scales: What can we learn from Empirical Mode Decom-position?, Geophys. Res. Lett., 37, 2010.

Langlais, B., V. Lesur, M.E. Purucker, J.E.P. Connerney, and M. Mandea, Crustal Magnetic Fields of Terrestrial Planets, Space Sci. Rev., 152 (1-4), 223-249, 2010.

Mitchell, R.N., P.F. Hoffman, and D.A.D. Evans, Coronation loop resurrected: Oscillatory apparent polar wander of Oro-sirian (2.05-1.8 Ga) paleomagnetic poles from Slave craton, Precambrian Res., 179 (1-4), 121-134, 2010.

Olson, P.L., R.S. Coe, P.E. Driscoll, G.A. Glatzmaier, and P.H. Roberts, Geodynamo reversal frequency and heterogeneous core-mantle boundary heat flow, Phys. Earth Planet. Int., 180, 66-79, 2010.

Opdyke, N.D., D.V. Kent, K.N. Huang, D.A. Foster, and J.P. Patel, Equatorial paleomagnetic time-averaged field results from 0-5 Ma lavas from Kenya and the latitudinal variation of angular dispersion, Geochem. Geophys. Geosys., 11, 2010.

Yamamoto, Y., H. Shibuya, H. Tanaka, and H. Hoshizumi, Geo-magnetic paleointensity deduced for the last 300 kyr from Un-zen Volcano, Japan, and the dipolar nature of the Iceland Basin excursion, Earth Planet. Sci. Lett., 293, 236-249, 2010.

Yokoyama, Y., T. Yamazaki, and H. Oda, Geomagnetic 100-kyr variation excited by a change in the Earth’s orbital eccentricity, Geophys. Res. Lett., 37, 2010.

Magnetic Field Records and Paleointensity MethodsBiggin, A.J., Are systematic differences between thermal and

microwave Thellier-type palaeointensity estimates a conse-quence of multidomain bias in the thermal results?, Phys. Earth Planet. Int., 180 (1-2), 16-40, 2010.

Inoue, S., and T. Yamazaki, Geomagnetic relative paleointensity chronostratigraphy of sediment cores from the Okhotsk Sea, Palaeogeog. Palaeocl., 291 (3-4), 253-266, 2010.

Macri, P., L. Sagnotti, J. Dinares-Turell, and A. Caburlotto, Relative geomagnetic paleointensity of the Brunhes Chron and the Matuyama-Brunhes precursor as recorded in sediment core from Wilkes Land Basin (Antarctica), Phys. Earth Planet. Int., 179, 72-86, 2010.

Muxworthy, A.R., Revisiting a domain-state independent method of palaeointensity determination, Phys. Earth Planet. Int., 179, 21-31, 2010.

Paterson, G.A., D. Heslop, and A.R. Muxworthy, Deriving confidence in paleointensity estimates, Geochem. Geophys. Geosys., 11, 2010.

Yang, T.S., M. Hyodo, Z.Y. Yang, H.D. Li, and M. Maeda, Multiple rapid polarity swings during the Matuyama-Brunhes transition from two high-resolution loess-paleosol records, J. Geophys. Res., 115, 2010.

Rock and Mineral MagnetismBezaeva, N.S., J. Gattacceca, P. Rochette, R.A. Sadykov, and

V.I. Trukhin, Demagnetization of terrestrial and extraterrestrial rocks under hydrostatic pressure up to 1.2 GPa, Phys. Earth Planet. Int., 179 (1-2), 7-20, 2010.

Cao, C.Q., L.X. Tian, Q.S. Liu, W.F. Liu, G.J. Chen, and Y.X. Pan, Magnetic characterization of noninteracting, randomly oriented, nanometer-scale ferrimagnetic particles, J. Geophys. Res., 115, 2010.

Carporzen, L., and S.A. Gilder, Strain memory of the Verwey transition, J. Geophys. Res.-Solid Earth, 115, 2010.

Carvallo, C., P. Sainctavit, M.A. Arrio, Y. Guyodo, R.L. Penn, B. Forsberg, A. Rogalev, F. Wilhelm, and A. Smekhova, Self-reversal of magnetization in oceanic submarine basalts studied with XMCD, Geophys. Res. Lett., 37, 2010.

Dallanave, E., L. Tauxe, G. Muttoni, and D. Rio, Silicate weathering machine at work: Rock magnetic data from the late Paleocene-early Eocene Cicogna section, Italy, Geochem. Geophys. Geosys., 11, 2010.

Lanci, L., Detection of multi-axial magnetite by remanence effect on anisotropy of magnetic susceptibility, Geophys. J. Int., 181 (3), 1362-1366, 2010.

Liu, C.C., C.L. Deng, Q.S. Liu, L.T. Zheng, W. Wang, X.M. Xu, S. Huang, and B.Y. Yuan, Mineral magnetism to probe into the nature of palaeomagnetic signals of subtropical red soil sequences in southern China, Geophys. J. Int., 181 (3), 1395-1410, 2010.

Liu, Q.S., Q.L. Zeng, J.P. Zheng, T. Yang, N. Qiu, Z.F. Liu, Y.H. Luo, and Z.M. Jin, Magnetic properties of serpentinized garnet peridotites from the CCSD main hole in the Sulu ultrahigh-pressure metamorphic belt, eastern China, J. Geophys. Res., 115, 2010.

Liu, S.M., W.G. Zhang, Q. He, D.J. Li, H. Liu, and L.Z. Yu, Magnetic properties of East China Sea shelf sediments off the Yangtze Estuary: Influence of provenance and particle size, Geomorphology, 119 (3-4), 212-220, 2010.

Robinson, P., K. Fabian, and S.A. McEnroe, Geometry of ionic arrangements and magnetic interactions in ordered ferri-ilmenite solid solutions and its effect on low-T magnetic behavior, Geochem. Geophys. Geosys., 11, 2010.

Usui, Y., and S. Yamazaki, Salvaging primary remanence from hydrothermally altered oceanic gabbros in the Oman ophiolite: A selective destructive demagnetization approach, Phys. Earth Planet. Int., 181 (1-2), 1-11, 2010.

Mineral Physics and ChemistryDuffy, J.A., J.W. Taylor, S.B. Dugdale, C. Shenton-Taylor, M.W.

Butchers, S.R. Giblin, M.J. Cooper, Y. Sakurai, M. Itou, Spin and orbital moments in Fe3O4, Phys. Rev. B, 81, 134424 , 2010.

Frandsen, C., B.P. Burton, H.K. Rasmussen, S.A. McEnroe, and S. Morup, Magnetic clusters in ilmenite-hematite solid solutions, Phys. Rev. B, 81 (22), 2010.

Krycka, K.L., J.A. Borchers, R.A. Booth, C.R. Hogg, Y. Ijiri, W.C. Chen, S.M. Watson, M. Laver, T.R. Gentile, S. Harris, L.R. Dedon, J.J. Rhyne, and S.A. Majetich, Internal magnetic structure of magnetite nanoparticles at low temperature, J. Appl. Phys., 107 (9), 2010.

Larese-Casanova, P., S.B. Haderlein, and A. Kappler, Biomin-eralization of lepidocrocite and goethite by nitrate-reducing Fe(II)-oxidizing bacteria: Effect of pH, bicarbonate, phos-phate, and humic acids, Geochim. Cosmochim. Acta, 74 (13), 3721-3734, 2010.

Peregrinus’s magnetic perpetual motion machine.

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for recovering relative paleointensity from samples with a multi-component thermal remanence. Friday afternoon’s session – organized by Mike Fuller (University of Hawaii) and Kristin Lawrence (Stanford University) – was devoted to Extraterrestrial Magnetism. Richard Harrison (Cambridge University) discussed the potential for using chondrule-derived dusty olivines to recover information about geomagnetic fields in the early solar system. Ian Garrick-Bethel (University of California, Santa Cruz) presented data from a lunar troctolite and spoke about the resulting implications for lunar paleointensity and lunar dynamo existence and timing. Kristin Lawrence (Stanford University) gave an overview talk focusing on the paleointensity of extrater-restrial (predominantly lunar) materials. Saturday morning started off with the second keynote lecture by Brandy Toner (University of Minnesota) on the biogeochemical signatures of iron oxyhydroxides in deep-sea deposits. By combining synchrotron radia-tion X-ray techniques with Mössbauer spectroscopy and magnetic measurements, Toner is trying to understand and distinguish the biotic and abiotic pathways that Fe

John Geissman (University of New Mexico) describes the outcrops near Jaramillo Creek. (Photo by Mike Jackson.)

Nabi, H.S., R.J. Harrison, and R. Pentcheva, Magnetic coupling parameters at an oxide-oxide interface from first principles: Fe2O3-FeTiO3, Phys. Rev. B, 81 (21), 2010.

Skomurski, F.N., S. Kerisit, and K.M. Rosso, Structure, charge distribution, and electron hopping dynamics in magnetite (Fe3O4) (100) surfaces from first principles, Geochim. Cos-mochim. Acta, 74 (15), 4234-4248, 2010.

OtherAubourg, C., and J.P. Pozzi, Toward a new < 250 degrees C

pyrrhotite-magnetite geothermometer for claystones, Earth Planet. Sci. Lett., 294 (1-2), 47-57, 2010.

Jackson, M., J.A. Bowles, I. Lascu, and P. Solheid, Deconvolu-tion of u channel magnetometer data: Experimental study of accuracy, resolution, and stability of different inversion methods, Geochem. Geophys. Geosys., 11, 2010.

Kodama, K.P., D.J. Anastasio, M.L. Newton, J.M. Pares, and L.A. Hinnov, High-resolution rock magnetic cyclostratigraphy

Peter Olson, Johns Hopkins University. (Photo by Christoph Geiss.)

Santa Fe Conference. Continued from pg. 1.

in an Eocene flysch, Spanish Pyrenees, Geochem. Geophys. Geosys., 11, 2010.

Langereis, C.G., W. Krijgsman, G. Muttoni, and M. Menning, Magnetostratigraphy - concepts, definitions, and applications, Newsletters on Stratigraphy, 43 (3), 207-233, 2010.

Odawara, S., K. Muramatsu, S. Komori, K. Kamata, K. Yamaza-ki, T. Yamaguchi, M. Sakakibara, T. Shinnoh, M. Simokawa, N. Ishikawa, and T. Meguro, Method for Evaluating Shielding Factor of Double Layered Magnetically-Shielded Rooms for Uniform Magnetic Field Using Exciting Coils Placed on One Side, Ieee Trans. Magn., 46 (6), 2357-2360, 2010.

Tominaga, M., and W.W. Sager, Revised Pacific M-anomaly geomagnetic polarity timescale, Geophys. J. Int., 182 (1), 203-232, 2010.

Uehara, M., C.J. van der Beek, J. Gattacceca, V.A. Skidanov, and Y. Quesnel, Advances in magneto-optical imaging applied to rock magnetism and paleomagnetism, Geochem. Geophys. Geosys., 11, 2010.

follows in deep-ocean cycling. The keynote lecture was followed by a general session on Environmental Magne-tism, convened by Christoph Geiss (Trinity College) and Richard Reynolds (US Geological Survey). Ted Evans (University of Alberta) gave a nice review talk on loess-paleosol magnetism, followed by Subir Banerjee (Uni-versity of Minnesota) on the search for a model of loess alteration. Banerjee questioned under what conditions loess magnetism reflects paleoclimate and asked whether it is possible that ferrihydrite is the precursor to all other authigenic magnetic minerals in soils. An overview talk by Eduard Petrovsky (Institute of Geophysics, ASCR) on the current state of environmental magnetism focussed on the utility of easily-made susceptibility measurements. Andrew Newell (North Carolina State University) and Aleksey Smirnov (Michigan Technological Univer-sity) organized the Saturday afternoon session devoted to the “Quantitative Modeling of Mineral Magnetic Data.” Ramon Egli (Ludwig-Maximilians University) presented recent work on modeling single-domain contributions in sediment using a Preisach/FORC approach. This was fol-lowed by Richard Harrison (Cambridge University) who provided an overview of atomistic simulations: what are

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they, how do they work, and how they can be used in rock and mineral magnetism. Andrew Newell (North Carolina State University) gave a talk on domain wall pinning. The meeting closed on Sunday morning with a session devoted to discussion of an upcoming Summer School in Rock Magnetism to be held at the IRM in the summer of 2011. Bruce Moskowitz (University of Minnesota) and Laurie Brown (University of Massachusetts) led the discussion, which included debate over who should be targeted, and what the subject matter and format of the school should be. The Sunday morning session was perhaps a fitting way to end the meeting: looking towards the future of the field and considering how to educate the next generation of rock magnetists. Based on the breadth and depth of topics discussed at the meeting, it promises to be a bright future.

ReferencesDoell, R.R., and G.B. Dalrymple, Geomagnetic polarity epochs:

a new polarity event and the age of the Brunhes-Matuyama boundary, Science, 152, 1060-1061, 1966.

Singer, B., and L.L. Brown, Santa Rosa Event: 40Ar/39Ar and paleomagnetic results from the Valles rhyolite near Jaramillo Creek, Jemez Mountains, New Mexico, Earth Planet. Sci. Lett., 197, 51-64, 2002.

Petrus Peregrinus(or, Pierre de Maricourt)fl. 1269, France

Little is known about this 13th century French scholar, apart from his manuscript on magnetism, Epistola de magnete. When the work was composed in 1269, Per-egrinus may have been a crusader in the army of Charles, duke of Anjou, during the siege of Lucera. The Epistola contains the first known description of a freely-pivoting (dry) magnet. He also provides the first extant European description of magnetic polarity, describes the properties and effects of magnets on each other, and tries to prove the possibility of perpetual motion with magnets. This text is also noted for his application of inductive reason-ing and use of experimental methods to draw conclusions. In addition to his studies on magnetism, Peregrinus also wrote a manuscript describing a complicated universal astrolabe that was not widely adopted. In 2005, the Eu-ropean Geophysical Union established the Petrus Pereg-rinus Medal for outstanding contributions in the field of magnetism and paleomagnetism.

Application deadline for 2011 Visiting Fellows (Jan - June):

October 31

Visit www.irm.umn.edu/IRM/Visiting.html for new application forms and instructions.

Visiting FellowsJune - December, 2010

Stacey Emmerton Imperial College London

Understanding the formation process of magnetic minerals in oil sands

Yifan Hu University of Florida

Demystifying the high-inclination, high-coercivity, NRM component in sediments from eastern equatorial

Pacific (IODP Expedition 320/321)

Tomas KohoutUniversity of Helsinki

High temperature magnetic properties of kamacite-taenite-iron mixtures observed in meteorites

Dan McCuan*California State University, Bakersfield

Late Pleistocene Paleomagnetic Field Record from the Sediments of Summer Lake, Oregon

Neil Ringerwole*Grand Valley State University

Tobago, West Indies, incremental vertical axis rotation history

Peter Selkin University of Washington, Tacoma

Magnetic Characterization of Emissions from the Tacoma Smelter

Rob SternbergFranklin & Marshall College

Low-temperature properties of central Mediterranean and Southwestern U.S. obsidians

Arlo Weil Bryn Mawr College

Complementary Rock Magnetic data to support ongoing research into Orogenic Curvature

* US Student Fellowships

Conference participants are transfixed by a particularly interesting data set: the World Cup scores. (Photo by Chuang Xuan.)

University of Minnesota291 Shepherd Laboratories100 Union Street S. E.Minneapolis, MN 55455-0128phone: (612) 624-5274fax: (612) 625-7502e-mail: irm@umn.eduwww.irm.umn.edu

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QuarterlyThe IRM

The IRM Quarterly is published four times a year by the staff of the IRM. If you or someone you know would like to be on our mailing list, if you have something you would like to contribute (e.g., titles plus abstracts of papers in press), or if you have any suggestions to improve the newsletter, please notify the editor:Julie BowlesInstitute for Rock MagnetismUniversity of Minnesota291 Shepherd Laboratories100 Union Street S. E.Minneapolis, MN 55455-0128phone: (612) 624-5274fax: (612) 625-7502e-mail: jbowles@umn.eduwww.irm.umn.edu

The U of M is committed to the policy that all people shall have equal access to its programs, facilities, and employment without regard to race, religion, color, sex, national origin, handicap, age, veteran status, or sexual orientation.

The Institute for Rock Magnetism is dedi-cated to providing state-of-the-art facilities and technical expertise free of charge to any interested researcher who applies and is ac-cepted as a Visiting Fellow. Short proposals are accepted semi-annually in spring and fall for work to be done in a 10-day period during the following half year. Shorter, less formal visits are arranged on an individual basis through the Facilities Manager. The IRM staff consists of Subir Baner-jee, Professor/Founding Director; Bruce Moskowitz, Professor/Director; Joshua Feinberg, Assistant Professor/Associate Director; Jim Marvin, Emeritus Scientist; Mike Jackson, Peat Sølheid, and Julie Bowles, Staff Scientists. Funding for the IRM is provided by the National Science Foundation, the W. M. Keck Foundation, and the University of Minnesota.

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