Abstract
The largest occurrence of natural metallic iron on Earth is on the island of Disko, Greenland. Metallic iron is found there in a variety of different types, from small metal particles in basalts to large meter-sized blocks. We have studied three different types of metallic iron: small metal spherules (< 300 μm) in basaltic magma; larger metal grains (300 μm-3 mm), often composed of aggregates of smaller particles, in similar host rocks; and massive iron lumps (up to several tons). Analytical data for 13 siderophile elements in samples from these three types are presented. All metals analysed have a distinctly crustal pattern of siderophile elements. High Co/Ni, Re/Ir or W/Ir ratios clearly demonstrate that a meteoritic origin for the metallic iron must be excluded. Since the Co/Ni and Re/Ir ratios are approximately chondritic in the upper mantle of the Earth, a mantle origin for the Disko metals can also be ruled out. This supports earlier petrological and geological evidence that the metallic iron was formed through reduction of basaltic magma by carbon derived from Tertiary shales and coals. Significant differences in absolute and relative abundances of siderophile elements occur among the three kinds of metals. The strongly siderophile elements (e.g. Ir, Re, Ni) increase in concentration from the small metal spherules through the larger grains to the massive iron lumps. The contents of less strongly siderophile elements (P, W, Ga) decrease in the same sequence. Evidence is presented that the small metal spherules are formed by in situ reduction. Larger iron metal grains and massive iron lumps are composed of small spherules, accumulated by gravitational settling in a magma reservoir. These metal cumulates have extracted highly siderophile elements from a larger volume of basaltic melt.
References
Basaltic Volcanism Study Project (1981) Basaltic volcanism on the terrestrial planets. Pergamon Press, New York
Bird JM, Weathers MS (1977) Native iron occurrences of Disko Island, Greenland. J Geol 85:359–371
Bird JM, Goodrich CA, Weathers MS (1981) Petrogenesis of Uivfaq iron, Disko island, Greenland. J Geophys Res 86:11787–11805
Buchwald VF (1975) Handbook of iron meteorites. Berkeley Los Angeles London University of California Press
Chou CL, Shaw DM, Crocket JH (1983) Siderophile trace elements in the earth's oceanic crust and upper mantle. J Geophys Res 88:A507-A518
Crocket JH, Kuo HY (1979) Sources for gold, palladium and iridium in deep sea sediments. Geochim Cosmochim Acta 43:831–842
Ewart A (1979) A review of the mineralogy and chemistry of tertiary-recent dacitic, latitic, rhyolitic and related salic volcanic rocks. In: Barker F (ed) Trondhjemites, dacites and related rocks. Developments in petrology, vol 6. Elsevier, New York
Fundal E (1975) The Uivfaq dike and related hybrid dikes from southern Disko, West Greenland. Medd Grønl 195:1–28
Gladney ES, Burns CE, Roelandts I (1983) 1982 Compilation of elemental concentrations in eleven United States Geological Survey Rock Standards. Geostandards Newsl VII:3–226
Goodrich CA (1984) Phosphoran pyroxene and olivine in silicate inclusions in natural iron-carbon alloy, Disko Island, Greenland. Geochim Cosmochim Acta 48:1115–1126
Goodrich CA, Bird JM (1985) Formation of iron-carbon alloys in basaltic magma at Uivfaq, Disko Island: the role of carbon in mafic magmas. J Geol 93:475–492
Hansen M (1958) Constitution of binary alloys. McGraw-Hill, New York Toronto London
Hertogen J, Janssens M-J, Palme H (1980) Trace elements in ocean ridge basalt glasses: implications for fractionations during mantle evolution and petrogenesis. Geochim Cosmochim Acta 44:2125–2143
Jaguotz E, Palme H, Baddenhausen H, Blum K, Cendales M, Dreibus G, Spettel B, Lorenz V, Wänke H (1979) The abundances of major, minor and trace elements in the Earth's mantle as derived from primitive ultramafic nodules. Proc 10th Lunar Plant Sci Conf. Geochim Cosmochim Acta, Suppl 11:2031–2050
Kelly WR, Larimer JW (1977) Chemical fractionations in meteorites. VIII. Iron meteorites and the cosmochemical history of the metal phase. Geochim Cosmochim Acta 41:93–111
Kesson SE, Lindsley DH (1975) The effects of Al3+, Cr3+ and Ti3+ on the stability of armalcolite. Proc 6th Lunar Planet Sci Conf (Geochim Cosmochim Acta [Suppl 6]) 1:911–920
Kruse H (1979) Spectra processing with computer graphics. In: Computers in activation analysis and gamma ray spectroscopy. Proceedings of the American Nuclear Society Topical Conference at Mayaguez, Puerto Rico, DOE, Conf-78421, pp 76–84
Kubaschewski O (1982) Iron-binary phase diagrams. Springer, Berlin Heidelberg New York
Lindsley DH, Kesson SE, Hartzman MJ, Cushman MK (1974) The stability of armalcolite: experimental studies in the system MgO-Fe-Ti-O. Proc 5th Lunar Conference (Geochim Cosmochim Acta [Suppl 5]) 1:521–534
Mason B (1971) Handbook of elemental abundances in meteorites. Gordon and Breach, New York Paris London
Melson WG, Switzer G (1966) Plagioclase-spinel graphite xenoliths in metallic iron-bearing basalts, Disko Island, Greenland. Am Mineral 51:664–676
Morgan JW, Wandless GA, Petrie RK, Irving AJ (1981) Composition of the earth's upper mantle. I. Siderophile trace elements in ultramafic nodules. Tectonophysics 75:47–67
Murase T, McBirney AR (1973) Properties of some common igneous rocks and their melts at high temperatures. Geol Soc Am Bull 84:3563–3592
Myers J, Euster HP (1983) The system Fe-Si-O: oxygen buffer calibrations to 1,500 K. Contrib Mineral Petrol 82:75–90
Neumayr M (1897) Erdgeschichte Bd 1 S 108, 116. Bibliographisches Institut, Leipzig Wien
Newsom HE, Palme H (1984) The depletion of siderophile elements in the Earth's mantle: new evidence from Molybdenum and Tungsten. Earth Planet Sci Lett 69:354–364
Nordenskiöld AE (1872) Account of an expedition to Greenland in the year 1870. Geol Mag 9:289–306, 355–368, 409–427, 449–463, 516–524
Palme H, Suess HE, Zeh HD (1981) Abundances of the elements in the solar system. In: Schaifers K, Voigt HH (eds) LandoldtBörnstein, vol 2 (Astron Astrophys). Springer, Berlin Heidelberg New York, pp 257–273
Pauly H (1969) White cast iron with cohenite, schreibersite and sulfides from tertiary basalts on Disko, Greenland. Medd Dan Geol Foren 19:8–26
Pedersen AK (1977a) Tertiary volcanic geology of the Mellemfjord area south-west Disko. Rapp Grønl Geol Unders 81:35–51
Pedersen AK (1977b) Dike intrusions along the south coast of Disko. Rapp Grønl Geol Unders 81:57–67
Pedersen AK (1977c) Iron bearing and related volcanic rocks in the area between Gieseckes Dal and Hammers Dal, north-west Disko. Rapp Grønl Geol Unders 81:5–14
Pedersen AK (1978) Graphitic andesite tuffs resulting from highMg tholeiite and sediment interaction; Nugssuaq, west Greenland. Bull Geol Soc Den 27:117–130
Pedersen AK (1981) Armalcolite-bearing Fe-Ti oxide assemblages in graphite-equilibrated salic volcanic rocks with native iron from Disko, central west Greenland. Contrib Mineral Petrol 77:307–324
Schmitt W (1984) Experimentelle Bestimmung von Metall/Sulfid/ Silikat-Verteilungskoeffizienten geochemisch relevanter Spurenelemente. Dissertation, Universität Mainz
Scott ERD (1972) Chemical fractionation in iron meteorites and its interpretation. Geochim Cosmochim Acta 36:1205–1236
Wänke H, Rieder R, Baddenhausen H, Spettel B, Teschke F, Quijano-Rico M, Balacescu A (1970) Major and trace elements in lunar material. Proc Apollo 11 Lunar Sci Conf (Geochim Cosmochim Acta [Suppl 1]) 2:1719–1727
Wänke H, Baddenhausen H, Dreibus G, Jagoutz E, Kruse H, Palme H, Spettel B, Teschke F (1973) Multielement analyses of Apollo 15, 16, and 17 samples and the bulk composition of the moon. Proc Lunar Sci Conf 4th (Geochim Cosmochim Acta [Suppl 4]) 2:1461–1481
Weckwerth G (1985) Feasibility of beta-ray spectrometry in INAA: Applications in geoand cosmochemistry. In: Sansoni B (ed) Instrumentelle Multielementanalyse. VCH Verlagsgesellschaft, Weinheim
Wedepohl KH (1975) The contribution of chemical data to assumptions about the origin of magmas from the mantle. Fortschr Mineral 52:141–172
Wedepohl KH (1981) Der primäre Erdmantel (Mp) and die durch Krustenbildung verarmte Mantelzusammensetzung (Md). Fortschr Mineral 59:203–205
Wells PRA (1977) Pyroxene thermometry in simple and complex systems. Contrib Mineral Petrol 62:129–139
Yoder MS Jr, Tilley CE (1962) Origin of basalt magmas: an experimental study of natural and synthetic rock systems. J Petrol 3:342–532
Author information
Authors and Affiliations
Additional information
Part of a Ph.D. thesis by W. Klöck
Rights and permissions
About this article
Cite this article
Klöck, W., Palme, H. & Tobschall, H.J. Trace elements in natural metallic iron from Disko Island, Greenland. Contr. Mineral. and Petrol. 93, 273–282 (1986). https://doi.org/10.1007/BF00389387
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00389387