Planetary Science Letters Research Articles

Anomalous earthquakes on volcano ring-fault structures : G. Ekstrom, Earth & Planetary Science Letters, 128(3–4), 1994, pp 707–712

Anomalous earthquakes on volcano ring-fault structures : G. Ekstrom, Earth & Planetary Science Letters, 128(3–4), 1994, pp 707–712

Dinosauric demise

For more than a decade, many scientists have theorized that the disappearance of the dinosaurs may be due to the collision of a huge asteroid with Earth 65 mya. However, many gaps have persisted in the theory. Now NASA scientists offer a detailed explanation of how the impact may have led to the extinction of the dinosaur. In a recent issue of Earth and Planetary Science Letters, a team of scientists from the Jet Propulsion Laboratory's Earth and Space Sciences Division in Pasadena, Calif., write that the location of the impact was key.

Dynamical Lagrangian Remeshing (DLR): a new algorithm for solving large strain deformation problems and its application to fault-propagation folding : J. Braun & M. Sambridge, Earth & Planetary Science Letters, 124(1–4), 1994, pp 211–220

Dynamical Lagrangian Remeshing (DLR): a new algorithm for solving large strain deformation problems and its application to fault-propagation folding : J. Braun & M. Sambridge, Earth & Planetary Science Letters, 124(1–4), 1994, pp 211–220

Strange attractor dimension as a new measure of seismotectonics around Koyna Reservoir, India : H. N. Srivastava, S. N. Bhattacharya & K. C. S. Ray, Earth & Planetary Science Letters, 124(1–4), 1994, pp 57–62.

Strange attractor dimension as a new measure of seismotectonics around Koyna Reservoir, India : H. N. Srivastava, S. N. Bhattacharya & K. C. S. Ray, Earth & Planetary Science Letters, 124(1–4), 1994, pp 57–62.

Distribution of 230Th and 231Pa in the water column in relation to the ventilation of the deep Arctic basins

Distribution of 230Th and 231Pa in the water column was measured in the Eurasian basins of the Arctic Ocean, i.e. the Makarov, Amundsen and Nansen basins. The profiles obtained were compared to one previously published from the Alpha Ridge (Bacon et al., Earth and Planetary Science Letters, 95 (1989) 15–22. The Amundsen and Nansen basins are similar in their 23OTh and 231Pa distribution, whereas in the Makarov Basin and at the Alpha Ridge these radionuclides are comparatively enriched in the deep basin. This may be due to low particle flux in conjunction with low water mass renewal rates. The 230Th concentration in water depth < 1000 m in the Makarov Basin is relatively low compared with the Alpha Ridge, which may be caused by an exchange of water masses between the Amundsen and Makarov basins. In the Eurasian Basin Deep Water, 230Th profiles can be explained both by a scavenging model and by a mixing-scavenging model. Enhanced particle load caused by resuspension may explain the increased scavenging in the Eurasian Basin Bottom Water. The differences in scavenging between the Norwegian-Greenland Sea and the Eurasian basins at present are not large enough to cause significant fractionation between 230Th and 231Pa.

An inverse method for determining lithospheric strain rate variation on geological timescales : N. White, Earth & Planetary Science Letters, 122(3–4), 1994, pp 351–371

An inverse method for determining lithospheric strain rate variation on geological timescales : N. White, Earth & Planetary Science Letters, 122(3–4), 1994, pp 351–371

Nitrogen biogeochemical cycling in the northwestern Indian Ocean

The vertical distribution and fine scale structure of nitrate (NO3), nitrite (NO2), nitrous Oxide (N2O), phosphate (PO4), oxygen (O2) and chlorophyll α (chl α) were determined in the North Western Indian Ocean (NWIO) along a meridional section (67°E) from the Equator to the Gulf of Oman using an Autoanalyser for micromolar levels of nutrients, and chemiluminescence and gas chromatographic methods for nanomolar levels of NO3 and NO2 and N2O respectively. Three biogeochimically contrasting regimes were investigated: (1) the highly oligotrophic nutrient-depleted subtropical gyre; (2) the nonsoonal upwelling of nutrient-rich intermediate waters of the southeastern Arabian Coast; and (3) the denitrifying O2-depleted zone (ODZ; ca 150–1200 m depth) in the Arabian Sea. Concentrations of NO3 and NO2 were severely depleted in surface oligotrophic waters from the equator (average 43 and 3.6 nM respectively) to the subtropical gyre (12–15°N; average 13.3 and 2.0 nM respectively) with similar levels in the more stratified Gulf of Oman. Upwelling waters off Southern Arabia had three orders of magnitude higher NO3 levels, and throughout the NWIO, the calculated NO3-fuelled primary production appeared to be regulated by NO3 concentration. Existing Redfield ΔO2/ΔNO3 regeneration ratios (=9.1) previously derived for the deep Indian Ocean were confirmed (= 9.35) within the oxic upper layers of the NWIO. The “NO”-potential temperature relationship (Broecker, 1974 Earth and Planetary Science Letters, 23, 100–107) needed for the derivation of expected NO3 and NO3-deficits within the denitrifying ODZ were refined using an isopycnal, binary mixing model along the σθ = 26.6%, density layer to take into account the inflowing contribution of NO3-depleted Persian Gulf Water. Vertically integrated NO3-deficits increased northwards from 0.8 mol NO3-N m−2 at Sta. 2 (04°N), up to 6.49 mol NO3-N m−2 at Sta. 9, at the mouth of the Gulf of Oman, then decreased to 4.10 moles NO3-N m−2 toward Sta. 11, near the Straits of Hormuz. When averaged for the denitrification area of the Arabian Sea, this corresponds to a deficit of 118 Tg NO3-N. Adopting a recent Freon-11 based estimate of water residence time of 10 years (Olsonet al., 1993, Deep-Sea Research II, 40, 673–685) for the O2-depleted layer, we calculate an annual net denitrification flux of 11.9 Tg N to the atmosphere or approximately 10% of the global water column denitrification rates. Supersaturated N2O concentrations were found in both surface oxic and upwelling waters (up to 246%) and peaked at the base of the ODZ (up to 1264%) in the northern Arabian Sea. Both nitrification in oxic waters and denitrification in hypoxic layers can be invoked as sources of N2O. The inventory of excess N2O amounted to 2.55 ± 1.3 Tg N2O-N, corresponding to annual production of 0.26 ± 0.13 Tg from denitrification. This is comparable to earlier (Law and Owens, 1990, Nature, 346, 826–828) estimates of the ventilation flux of N2O (0.22–0.39 Tg yr−1) from the upwelling region of the Arabian Sea. The decadal response times for circulation, deoxygenation, denitrification and ventilation of the ODZ-derived N2O and CO2 greenhouse gases and their monsoonal coupling implies the Arabian Sea is a sensitive oceanic recorder of global climate change.

Precambrian basement in the Canadian Cordillera: an introduction

s, 15: A4. ARMSTRONG, R. L., TAUBENECK, W. H., and HALES, P. 0.1977. Rb-Sr and K-Ar geochronometry of Mesozoic granitic rocks and their Sr isotopic composition, Oregon, Washington and Idaho. Geological Society of America Bulletin, 88: 39741 1. BALLY, A. W., GORDY, P. L., and STEWART, G. A. 1966. Structure, seismic data and orogenic evolution of southern Canadian Rockies. Bulletin of Canadian Petroleum Geology, 14: 337-381. BENNETT, V. C., and DEPAOLO, D. J. 1987. Proterozoic crustal history of the western United States as determined by neodymium isotopic mapping. Geological Society of America Bulletin, 99: 674-685. BERRY, M. J., JACOBY, W. R., NIBLEIT, E. R., and STACEY, R. A. 1971. A review of geophysical studies in the Canadian Cordillera. Canadian Journal of Earth Sciences, 8: 788-801. BOWRING, S. A., and PODOSEK, F. P. 1989. Nd isotopic evidence from Wopmay Orogen for 2.0-2.4 Ga crust in western North America. Earth and Planetary Science Letters, 94: 217-230. BURWELL, A. D. M. 1975. Rb-Sr isotope geochemistry of lherzolites and their constituent minerals from Victoria, Australia. Earth and Planetary Science Letters, 28: 69-78. CAMPBELL, R. B. 1968. Canoe River, British Columbia. Geological Survey of Canada, Map 15-1967. CARR, S. D., and BROWN, R. L. 1990. Southern Cordilleran Lithoprobe transect lines 6 to 10: crustal structure and tectonic chronology. Southern Canadian Cordillera Transect Workshop, March 3 4 , University of Calgary, Calgary, Alta., pp. 10-18. COLLERSON, K. D., VAN SCHMUS, W. R., LEWRY, J. F., and BICKFORD, M. E. 1988. Buried Precambrian basement in south-central Saskatchewan: provisional results from Sm-Nd model ages and U-Pb zircon geochronology. In Summary of investigations 1988. Saskatchewan Geological Survey, Miscellaneous Report 88-4, pp. 142-150. COOK, F. A., SIMONY, P. S., COFLIN, K. C., GREEN, A. G., MILKEREIT, B., PRICE, R. A., PARRISH, R., PATENAUDE, C., GORDY, P. L., and BROWN, R. L. 1987. Lithoprobe southern Canadian Cordilleran transect: Rocky Mountain thrust belt to Valhalla gneiss complex. Geophysical Journal of the Royal Astronomical Society, 89: 91-

Constructional features of the Troodos ophiolite and implications for the distribution of orebodies and the generation of oceanic crust: Discussion

It is not important whether these rocks end up being called members of the sanukitoid suite. What is important is understanding why certain Archean calc-alkaline rocks tend to have higher Ni and Cr contents and are thus more primitive than most modem calc-alkaline rocks. We need to be able to distinguish the intermediate to siliceous rocks with high Ni, Cr, and LILE abundances and high Mg#'s from other calcalkaline rocks, evaluate their abundance, and determine their origin, because they may be an important ingredient in the evolution of the continental crust. We recommend the use of the term sanukitoid suite, because giving this suite of rocks an unambiguous name-whatever the name-helps us to distinguish, describe, and discuss them. KOTO, B. 1916. On the volcanoes of Japan, part V. Journal of the Geological Society of Japan, 23: 95-127. NIELSEN, R. L. 1985. EQUIL: a program for the modeling of low-pressure differentiation processes in natural mafic magma bodies. Computers and Geosciences, 11: 53 1-546. 1988. TRACE.FOR: a program for the calculation of combined major and trace-element liquid lines of descent for natural magmatic systems. Computers and Geosciences, 14: 15-35. TATSUMI, Y., and ISHIZAKA, K. 1982. Origin of high-magnesian andesites in the Setouchi volcanic belt, southwest Japan, I. Petrological and chemical characteristics. Earth and Planetary Science Letters, 60: 293-304.

226Ra and Ba in northeast Atlantic deep water

226Ra and Ba data are presented for the northeast Atlantic below 2000 m depth from a section of stations 8°S to 46°N obtained by F.S. Meteor in 1981. The precision of the 226Ra data (±1%) allows a resolution of structures in the 226Ra distribution that is comparable to the resolution for Ba and nutrients. Linear property—property correlations in the upper parts of the depth range appear to be uniform within the observational error along the section for 226Ra, Ba [Ba(nmol kg −1) = 3.88 Ra (dpm 100 kg −1) + 12.3], and alkalinity, whereas the slopes of these properties versus Si increase northwards from about 10 to 25 × 10 −4 dpm Ra μmol Si −1. From this observation, and from studying the property distributions across the Romanche Fracture Zone, it is concluded that CaCO 3 dissolution must be an important process of 226Ra and barium regeneration, while opal dissolution appears to be of minor importance. The water overflowing eastward over the sill of the Romanche Fracture Zone has 17.2 ± 0.3 dpm 100 kg −1 226Ra, 79.5 ± 1.5·nmol kg −1 Ba and 2338 ± 4 μeq kg −1 alkalinity. Within 800–1400 m above the sea floor, excess 226Ra relative to the linear correlation with Ba further up in the water column is generally present, but there is also a reflection of 226Ra decay at intermediate depths at the northern stations of the section. The latter effect appears to amount to only 3 ± 1.5%, but this magnitude is consistent with the 14C distribution reported previously ( Schlitzer et al., Journal of Geophysical Research, 90, 6945–6952, 1985). From the excess 226Ra in the lowest 800–1400 m of the water column, the 226Ra flux from the sediments is estimated to be 7.7 ± 4 × 10 −21 mol Ra (m 2s) −1, a value in accordance with results by Cochran ( Earth and Planetary Science Letters, 49, 381–392, 1980).

Radiogenic heat production in continental lithosphere”

About half the heat from continents is derived from the radiogenic decay of trace quantities of the unstable isotopes of uranium, thorium, and potassium in the continental crust. This contribution to surface heat flow is highly variable, however, typically resulting in a large scatter of surface heat flow values even in stable regions. Approximately 20 years ago, careful work by Robert Roy, Ed Decker, and Dave Blackwell with Francis Birch (Earth and Planetary Science Letters, vol. 5, pp. 1–12, 1968) showed that for well determined heat flow values in plutonic rocks, surface heat flow is linearly related to surface heat production in a given province. This relationship allows heat flow to be separated into two components: heat generated in the upper crustal zone enriched in heat‐producing isotopes and heat from below this zone (the “reduced” heat flow). Art Lachenbruch quickly showed that the only distribution of heat production with depth that would satisfy this linear relationship under conditions of differential erosion is an exponential decrease with depth (in the Journal of Geophysical Research, vol. 73, pp. 6977–6989, 1968). The relationship has now been extended to include heat flow‐heat production data from high‐grade metamorphic rocks, and heat flow provinces have been defined in every continent except Antarctica. Two major problems remain, however:

Tabulation of recalculated radiometric ages published 1960–1979 for rocks and minerals in Sweden

Abstract Radiometric ages published 1960–1979 for Swedish rocks and minerals have been tabulated and, when appropriate, recalculated with the new recommended decay constants (R. H. Steiper & E. Jager, 1977: Convention on the use of decay constants in geo- and cosmochronology. Earth and Planetary Science Letters 36, 359–362).

Ancient Aurorae

Previous articleNext article No AccessAncient AuroraeRichard StothersRichard Stothers Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by Isis Volume 70, Number 1Mar., 1979 Publication of the History of Science Society Article DOIhttps://doi.org/10.1086/352156 Views: 7Total views on this site Citations: 28Citations are reported from Crossref Copyright 1979 History of Science Society, Inc.PDF download Crossref reports the following articles citing this article:Annarita Franza, Giovanni Pratesi Julius Obsequens’s book, Liber Prodigiorum : A Roman era record of meteorite falls, fireballs, and other celestial phenomena, Meteoritics & Planetary Science 128 (Jun 2020).https://doi.org/10.1111/maps.13525Liba Taub The Cambridge Companion to Ancient Greek and Roman Science, 1 (Jan 2020).https://doi.org/10.1017/9781316136096D. L. Neuhäuser, R. Neuhäuser, J. Chapman New sunspots and aurorae in the historical Chinese text corpus? Comments on uncritical digital search applications, Astronomische Nachrichten 339, no.11 (Feb 2018): 10–29.https://doi.org/10.1002/asna.201713390Hisashi Hayakawa, Kiyomi Iwahashi, Harufumi Tamazawa, Yusuke Ebihara, Akito Davis Kawamura, Hiroaki Isobe, Katsuko Namiki, Kazunari Shibata Records of auroral candidates and sunspots in Rikkokushi, chronicles of ancient Japan from early 7th century to 887, Publications of the Astronomical Society of Japan 69, no.66 (Oct 2017).https://doi.org/10.1093/pasj/psx087Hisashi Hayakawa, Harufumi Tamazawa, Yusuke Ebihara, Hiroko Miyahara, Akito Davis Kawamura, Tadanobu Aoyama, Hiroaki Isobe Records of sunspots and aurora candidates in the Chinese official histories of the Yuán and Míng dynasties during 1261–1644, Publications of the Astronomical Society of Japan 69, no.44 (Jul 2017).https://doi.org/10.1093/pasj/psx045Harufumi Tamazawa, Akito Davis Kawamura, Hisashi Hayakawa, Asuka Tsukamoto, Hiroaki Isobe, Yusuke Ebihara Records of sunspot and aurora activity during 581–959 CE in Chinese official histories concerning the periods of Suí, Táng, and the Five Dynasties and Ten Kingdoms, Publications of the Astronomical Society of Japan 69, no.22 (Feb 2017).https://doi.org/10.1093/pasj/psw132Miklós Kázmér, Gábor Timár The first scientific description of aurora borealis: the 10 September 1580 event in Transylvania, recorded by Marcello Squarcialupi, Geoscience Letters 3, no.11 (May 2016).https://doi.org/10.1186/s40562-016-0047-2Hisashi Hayakawa, Yasuyuki Mitsuma, Yusuke Ebihara, Akito Davis Kawamura, Hiroko Miyahara, Harufumi Tamazawa, Hiroaki Isobe Earliest datable records of aurora-like phenomena in the astronomical diaries from Babylonia, Earth, Planets and Space 68, no.11 (Nov 2016).https://doi.org/10.1186/s40623-016-0571-5Akito D. Kawamura, Hisashi Hayakawa, Harufumi Tamazawa, Hiroko Miyahara, Hiroaki Isobe Aurora candidates from the chronicle of Qíng dynasty in several degrees of relevance, Publications of the Astronomical Society of Japan 68, no.55 (Aug 2016): 79.https://doi.org/10.1093/pasj/psw074M. Korte, S. Stolze Variations in Mid-Latitude Auroral Activity During the Holocene*, Archaeometry 58, no.11 (Dec 2014): 159–176.https://doi.org/10.1111/arcm.12152Hisashi Hayakawa, Harufumi Tamazawa, Akito Davis Kawamura, Hiroaki Isobe Records of sunspot and aurora during CE 960–1279 in the Chinese chronicle of the Sòng dynasty, Earth, Planets and Space 67, no.11 (May 2015).https://doi.org/10.1186/s40623-015-0250-yGeorge L. Siscoe Evidence in the Auroral Record for Secular Solar Variability, (Mar 2013): 127–138.https://doi.org/10.1029/HG001p0127Marinus A. van der Sluijs Closing Gaps in Traditional Sky Lore, Perspectives on Science 20, no.11 (May 2012): 1–43.https://doi.org/10.1162/POSC_a_00055David H. Kelley, Eugene F. Milone Transient Phenomena, (Dec 2010): 109–153.https://doi.org/10.1007/978-1-4419-7624-6_5David M Willis, José M Vaquero, F Richard Stephenson Early observation of the aurora australis: AD 1640, Astronomy & Geophysics 50, no.55 (Oct 2009): 5.20–5.24.https://doi.org/10.1111/j.1468-4004.2009.50520.xJames Montgomery Spectral Armies, Snakes, and a Giant from Gog and Magog, The Medieval History Journal 9, no.11 (Apr 2006): 63–87.https://doi.org/10.1177/097194580500900104Ioannis Liritzis, Helen Vassiliou Were Greek temples oriented towards aurorae?, Astronomy and Geophysics 47, no.11 (Feb 2006): 1.14–1.18.https://doi.org/10.1111/j.1468-4004.2006.47114.xAndrew R. Solow On celestial events, auroral activity, and the solar cycle in classical antiquity, Earth and Planetary Science Letters 232, no.1-21-2 (Mar 2005): 67–70.https://doi.org/10.1016/j.epsl.2005.01.010Sam Silverman Early auroral observations, Journal of Atmospheric and Solar-Terrestrial Physics 60, no.1010 (Jun 1998): 997–1006.https://doi.org/10.1016/S1364-6826(98)00040-6Y. Liritzis Evidence for periodicities in the auroral occurrence frequency since 300 AD and their implications, Pure and Applied Geophysics PAGEOPH 133, no.22 (Apr 1990): 201–211.https://doi.org/10.1007/BF00877159Yiannis Liritzis Aurorae boreales and geomagnetic inclinations as aids to archaeomagnetic dating, Earth, Moon and Planets 42, no.22 (Aug 1988): 151–162.https://doi.org/10.1007/BF00054543Kevin D. Pang, Kevin Yau, Hung-hsiang Chou, Robert Wolff Computer analysis of some ancient Chinese sunrise eclipse records to determine the Earth's rotation rate, Vistas in Astronomy 31 (Jan 1988): 833–847.https://doi.org/10.1016/0083-6656(88)90317-0Vojtěch Leftus, J. Tomlain, V. Vítek Solar activity variations and climatic changes, Studia Geophysica et Geodaetica 30, no.11 (Mar 1986): 93–110.https://doi.org/10.1007/BF01630858J. Feynman Solar cycle and long term changes in the solar wind, (Jan 1986): 131–141.https://doi.org/10.1029/HG002p0131P. J. Bicknell The Date of Timoleon's Crossing to Italy and the Comet of 361 B.C., The Classical Quarterly 34, no.11 (Feb 2009): 130–134.https://doi.org/10.1017/S0009838800029360J. Feynman Solar cycle and long term changes in the solar wind, Reviews of Geophysics 21, no.22 (Jan 1983): 338.https://doi.org/10.1029/RG021i002p00338George L. Siscoe Evidence in the auroral record for secular solar variability, Reviews of Geophysics 18, no.33 (Jan 1980): 647.https://doi.org/10.1029/RG018i003p00647Robert H. Eather Majestic Lights: The Aurora in Science, History, and the Arts, (Jan 1980).https://doi.org/10.1029/SP018

Simulation of limestone diagenesis—a model based on strontium depletion: Discussion

preparation. Blueschist metamorphismin the Bathurst area of New Brunswick. HELMSTAEDT, H. 1973. Structural geology of the Bathurst-Newcastle district. In New England Intercollegiate Geological Conference (NEIGC) Geology of New Bmnswick Field Guide to Excursions. Edited by N. Rast. pp. 34-43. 1978. Geochemistry of volcanic rocks from the Tetagouche Group, Bathurst, New Brunswick, Canada: Discussion. Canadian Journal of Earth Sciences, 15, pp. 16801681. MCBRIDE, D. E. 1976. Tectonic setting of the Tetagouche Group, host to the New Bmnswick polymetallic massive sulphide deposits. Geological Association of Canada, Special Paper No. 14, pp. 473-485. PAJARI, G. E., RAST, N., and STRINGER, P. 1977. Paleozoic vulcanicity along the Bathurst-Dalhousie Geotraverse, New Brunswick, and its relation to structure. Geological Association of Canada, Special Paper No. 16, pp. 1 1 1-124. PEARCE, J. A., and CANN J . B. 1971. Ophlolite origin investigated by discriminant analysis using Ti, Zr and Y. Earth and Planetary Science Letters, 12, pp. 339-349. RAST, N., and STRINGER, P. 1974. Recent advances and the Interpretation of the geological structure of New Brunswick. Geoscience Canada, 1(4), pp. 15-25. SKINNER, R. 1974. Geology of the Tetagouche Lakes, Bathurst and Nepisiquit Falls map-areas, New Brunswick. Geological Survey of Canada, Memoir 37 1, 133 p. WHITEHEAD, R. E. S., and GOODFELLOW, W. D. 1978. Geochemistry of volcanic rocks from the Tetagouche Group, Bathurst, New Brunswick, Canada. Canadian Journal of Earth Sciences, 15, pp. 207-219. WILLIAMS, H., KENNEDY, M. J . , and NEALE, E. R. W. 1972. The Appalachian structural province. In Variations in tectonic styles in Canada. Edited by R. A. Price and R. J. W. Douglas. Geological Association of Canada, Special Paper No. 11,pp. 180-261.

Alternative kinetic models for the interpretation of amino acid enantiomeric ratios in Pleistocene mollusks: Examples from California, Washington, and Florida

Alternative kinetic models for amino acid racemization in Pleistocene molluscan samples are compared by examination of results for samples from marine Pleistocene deposits in California, Washington, and Florida. Linear kinetic models previously have been applied to the Florida samples [ Mitterer, R.M. (1975). Earth and Planetary Science Letters 28, 275–282.] because these kinetics were observed in laboratory pyrolysis experiments with the particular genus involved ( Mercenaria). Nonlinear kinetic models, extrapolated from deep-sea foraminifera racemization kinetics, are applied to samples of Protothaca and Saxidomus from California and Washington and seem more consistent with their local chronologic and stratigraphic control. Average or effective diagenetic temperatures can be estimated by each of these models if reliably dated samples are available. Linear models applied to such samples from California and Florida suggest average diagenetic temperatures that are cooler (by as much as 10°C) than would be inferred from available paleoclimatic records. Nonlinear kinetic models yield estimates of average diagenetic temperatures that are more consistent with these records: full-glacial (i.e., approximately 18,000 yr BP) temperature reductions of between 2 and 6°C are inferred for coastal California and southern Florida. The nonlinear kinetic model is used to expand (by a factor of 2.5 to 3.0) the time scale proposed by Mitterer (1975) for five marine Pleistocene units of Florida.

Statistical Classification of Garnets from Kimberlite and Associated Xenoliths: Addendum

Previous articleNext article No AccessStatistical Classification of Garnets from Kimberlite and Associated Xenoliths: AddendumJ. B. Dawson and W. E. StephensJ. B. Dawson Search for more articles by this author and W. E. Stephens Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Journal of Geology Volume 84, Number 4Jul., 1976 Article DOIhttps://doi.org/10.1086/628216 Views: 4Total views on this site Citations: 18Citations are reported from Crossref Copyright 1976 University of ChicagoPDF download Crossref reports the following articles citing this article:Agnes T. Fung, Stephen E. Haggerty Petrography and mineral compositions of eclogites from the Koidu Kimberlite Complex, Sierra Leone, Journal of Geophysical Research: Solid Earth 100, no.B10B10 (Sep 2012): 20451–20473.https://doi.org/10.1029/95JB01573Doris V. Hills, Stephen E. Haggerty Petrochemistry of eclogites from the Koidu Kimberlite Complex, Sierra Leone, Contributions to Mineralogy and Petrology 103, no.44 (Jan 1989): 397–422.https://doi.org/10.1007/BF01041749J.B. Dawson, J.V. Smith Relationships between eclogites and certain megacrysts from the Jagersfontein kimberlite, South Africa, Lithos 19, no.3-43-4 (Oct 1986): 325–330.https://doi.org/10.1016/0024-4937(86)90031-9M. Ito Kimberlites and their ultramafic xenoliths from western Kenya, TMPM Tschermaks Mineralogische und Petrographische Mitteilungen 35, no.33 (Jan 1986): 193–216.https://doi.org/10.1007/BF01082085R. L. Hervig, J. V. Smith, J. B. Dawson Lherzolite xenoliths in kimberlites and basalts: petrogenetic and crystallochemical significance of some minor and trace elements in olivine, pyroxenes, garnet and spinel, Transactions of the Royal Society of Edinburgh: Earth Sciences 77, no.33 (Nov 2011): 181–201.https://doi.org/10.1017/S026359330001083XColin H. Donaldson Kinetics of pyrope megacryst reactions in ascending basaltic magma – relevance to high-pressure magmatic crystallization at Elie Ness, East Fife, Geological Magazine 121, no.66 (May 2009): 615–620.https://doi.org/10.1017/S0016756800030752 References, (Jan 1984): 435–466.https://doi.org/10.1016/B978-0-444-42273-6.50037-7 References, (Jan 1984): 361–393.https://doi.org/10.1016/B978-0-444-42274-3.50036-6 Suzanne Mahlburg Kay , William T. Snedden , Brayton P. Foster , and Robert W. Kay Upper Mantle and Crustal Fragments in the Ithaca Kimberlites, The Journal of Geology 91, no.33 (Sep 2015): 277–290.https://doi.org/10.1086/628771SUZANNE Y. WASS, J. D. HOLLIS Crustal growth in south-eastern Australia?evidence from lower crustal eclogitic and granulitic xenoliths, Journal of Metamorphic Geology 1, no.11 (Mar 1983): 25–45.https://doi.org/10.1111/j.1525-1314.1983.tb00263.xD.B. Clarke, G.G. Pe-Piper Multiply exsolved clinopyroxene megacrysts from the Frank Smith Mine, Cape Province, South Africa, Lithos 16, no.11 (Jan 1983): 75–84.https://doi.org/10.1016/0024-4937(83)90036-1R.L. Hervig, J.V. Smith, I.M. Steele, J.B. Dawson Fertile and barren AlCr-spinel harzburgites from the upper mantle: Ion and electron probe analyses of trace elements in olivine and orthopyroxene: Relation to lherzolites, Earth and Planetary Science Letters 50, no.11 (Oct 1980): 41–58.https://doi.org/10.1016/0012-821X(80)90118-1N. P. Lock, J. B. Dawson Garnet-olivine reaction in the upper mantle: evidence from peridotite xenoliths in the Letseng-la-Terae kimberlites, Lesotho, Transactions of the Royal Society of Edinburgh: Earth Sciences 71, no.11 (Nov 2011): 47–53.https://doi.org/10.1017/S0263593300013481J. B. DAWSON, J. V. SMITH, J. S. DELANEY Multiple spinel–garnet peridotite transitions in upper mantle: evidence from a harzburgite xenolith, Nature 273, no.56655665 (Jun 1978): 741–743.https://doi.org/10.1038/273741a0F.C. Bishop, J.V. Smith, J.B. Dawson Na, K, P and Ti in garnet, pyroxene and olivine from peridotite and eclogite xenoliths from African kimberlites, Lithos 11, no.22 (Apr 1978): 155–173.https://doi.org/10.1016/0024-4937(78)90006-3J. B. Dawson, J. S. Delaney, J. V. SmitH Aspects of the mineralogy of aln�itic breccia, Malaita, Solomon Islands; comparison with continental kimberlites, Contributions to Mineralogy and Petrology 67, no.22 (Jan 1978): 189–193.https://doi.org/10.1007/BF01046575 W. E. Stephens , and J. B. Dawson Statistical Comparison between Pyroxenes from Kimberlites and Their Associated Xenoliths, The Journal of Geology 85, no.44 (Sep 2015): 433–449.https://doi.org/10.1086/628317

The distribution of 3He in the western Atlantic ocean

Over 250 samples of Atlantic seawater have been analyzed for the dissolved helium isotopes, and distinctive pattern has emerged. Two components of excess 3He are seen: a component due to in situ decay of nuclear-era tritium, and a primordial component evolved from the solid Earth. A prominent feature at about 3-km depth can be traced from 5°N along the western boundary to the equator. The source of this feature is most probably in the Gibbs fracture zone, where we suppose that primordial 3He is released into westward-flowing bottom water. The South Atlantic profiles clearly show the effect of 3He-rich CCircumpolar Water, entrained by Antarctic Intermediate Water flowing northward. The excess 3He in the upper 1 km, when combined with tritum concentrations measured byO¨stlund, Dorsey and Rooth (1974, Earth and Planetary Science Letters, 23, 69–86) at the same locations and depths, yields ‘tritium-helium ages’, which in some cases represent the time interval between equilibration wwith the atmosphere and sampling.

President's page: International support for Chilean geophysicists

No. But I'm known to be prejudiced in this area. Decide for yourself.One dollar buys your library about 46,000 words of JGR. This amount of material costs over $4.00 in Earth and Planetary Science Letters and Geochima et Cosmochimica Acta, two of the more reasonably priced, commercially published journals and about $9.50 in Geophysical Surveys. But, you say, ‘ Wait a minute! What about the page charge of $80? That's 6.5c per word.’ OK; if there were no page charge, your library would still pay less than $2.40 for those 46,000 words.

Comments on ‘palaeomagnetism of the Cambrian Purple Sandstone from the Salt-Range, W. Pakistan’: by M.W. McElhinny, earth and planetary science letters 8 (1970) 149–156

Comments on ‘palaeomagnetism of the Cambrian Purple Sandstone from the Salt-Range, W. Pakistan’: by M.W. McElhinny, earth and planetary science letters 8 (1970) 149–156

Comments on “lunar seismograms for LM and S-IVB impacts interpreted as modulation mirage”: by E. Strick, earth and planetary science letters 13 (1972) 23–31.

Comments on “lunar seismograms for LM and S-IVB impacts interpreted as modulation mirage”: by E. Strick, earth and planetary science letters 13 (1972) 23–31.