THE ABUNDANCE AND DISTRIBUTION OF THE CHEMICAL ELEMENTS IN THE EARTH'S CRUST' MICHAEL FLEISCHER U. S. Geological Survey, Washington, D. C.
Tm
study of the abundance and distrihution of elements in the earth's crust is so hroad t,hat no more than a sketchy survey can be made here. Every chemist should have some familiarity with the subject, hut the general experience of those whose work deals with raw
Staff of
U. S.
Oeolwic~lSurvey L a b o n t o ~ yof
Physicnl and Chemical
Research. 1886
I.eft to right, rcnr: F. W. Clarke, W. Ii. Elillehmnd, T. M. Chntard, J. Hallock; front, .I. E. Whitfield, F. A. Gooelr. Carl Barus, and It. B. Riasa. Whitfield we.8 later a partner for Inany yeara in the laboratory of Booth. Garrett, and Blair. Pldadelpl~in: Goooh was Professor of Clmndstry n t Yale College; Rarus was Professor of Physica at Brown University; Rigm was Professor of Chemistry n t Trinity College, Hnrtford, Connecticut.
In this paper an nthempt is made to look a lit,tle deeper than t,hat into the subject: to summarize the data on t.he ahundanees of the elements, to discuss t,heir distribution among different types of rocks, and to examine t,he callses of the observed variations in distribution. As might be expected, the abundance and distribntion of elements were long ago suhjects of interest. More than 100 years ago estimates of abundance mere made by IXhereiner in Germany, and a list of the types of roeks in which 59 elements were most likely t.o be found was made by de Beaumont, a French geologist. Other est,imates of the abundances of the elements appeared in lat,er years hut were not aeeurat,e because few relial~leanalyses were available. The first estimates of the ahundanee of elements of any accuracy were made ahout, 1890 after t,he met,hods of quantitat,ive analyses of roeks had heen great,ly improved. This improvement was dne largely t,o the work of the chemists of the U. S. Geological Survey. From 1880 to 1910 this group put the det,erminat,ion of the major eonst,itnent,s of rocks on a firm hasis and also showed that more consideration should he given to some of t,he less a1)undant element,^, m r h as t,it,nnium, vanadium, and molybdenum. The leader in t,his analytical work mas W. F. Hillehrand, chcrnist of t,he U. S. Geological Survey from 1880 t,o lW!) and rhief chemist of the National Bnreau of Standards from 1!)09 t,o 1925.2 Morn than any ot,her person, IIillehrand was responsible for the methods of inorganic analysis that we are using today. His hook, "The Analysis of Silicate and Carhonat,e Rocks," first appeared in 1897 as a hrief section in 11. S. Geologiral Snrvey Bulletin No. 148. I t was so popular t,hat revised editions appeared in 1900, 1907, and 1910; widened in scope, it, reappeared in 1929 as "Inorganic Chemical Analysis," hy Hillehrand and I,nndell, which has heen called "the bihle of inorganic analysis"; rl revised edit,ion appeared in 1953. With sound methods of aoalvsis. it, hecame nossible
SEPTEMBER. 1954
447
U. S. Geological Survey Bulletin S o . 770, is now out of date hut is still in so much demand that it has been reprinted twice in the last few yeam3 A revision, which will require several years, is now under way. During this same period, others contributed much to our knowledee. amone them H. S. Washineton in the
orw way,
arose a t the University of Oslo, under the leadership of V. M. Goldschmidt. In a series of nine oaoers., he and his co-workers Zachariasen. Barth, Lnnde, and others used the new tool of x-ra; crystallography to deduce t,he principles of crystal chemistry and further applied these principles to the elucidation of the occurrences of the elements. From 1929 to 1935, when he was expelled by the Nazis, Goldschmidt was at the University of Gottingen, where he used the spectrographic method of analysis for the less abundant elements and greatly extended our knowledge in this direction. He continued his work at Oslo and, aft,er escaping from Norway, in England until his A
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peared in the 18901s,and by his student A. E. Fersman. Vernadsky partirularly emphasized the effects of biological processes on the dispersion and concentration of the elements. Some aspects of this field, n-hich he named hiogeochemistry, are discussed below. Fers-
I
man was a prodigious worker; he published nearly 700 papers, including a dozen large monographs. He emphasized the application of t,hermodynamics and of quantitative measurements of energy changes to the study of geological proce~ses.~ It is pleasant to be able to close t,his hrief historical See SPENCER, L. J., A m Minwalogist, 31, 173-8 (1946) on T. M., iWrl., 32, 181-8 (194;) on Feramnn; STADN~CHDVKO, Vern.~dskv.
J. C h r m i o c
(London1
V. M. Goldschmidt. 1888-1947
death in 1947.' Similar work was done in Germany and Scandinavia, especially by the Noddacks and by Hevesy. Research in this field is active in Scandinavia, England, Germany, and the United States; much of it can be traced to Goldschmidt's influence. Another great center of research in geochemistry has been Russia. Work there was led by V. I. Vernadsky, whose first DaDers . . on distribution of the elements aDFor biographies of Clarke, see MUNROE, C. E., J. Am. Chem. Sac., 57,21-30 (1935); DENNIS, 1,. M., Nal. Acad. Sci. Biographical Mem., 15, 139-65 (1932). 4See BERNAL, J. D., "Goldschmidt memorial lecture," J. Chem. Soe. (London), 1949, 2108-14; TILLEY,C. E., Obiltranj Notiem of Fellows of Lhe Royal Society, 6 , 51-66 (1948).
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JOURNAL OF CHEMICAL EDUCATION
given in Table 1. It will be noted that one element, oxygen, constitutes nearly half the earth's crust and that the 12 most abundant elements constitute 99.5 per cent; all the other 86 elements combined constitute only 0.5 per cent of the earth's crust. Nine elements-&ose of atomic numbers 43, 61, 85, 87, 93, Oxygen Silicon 95, 96, 97, and 98-have not yet been shown to occur Aluminum naturally at all. Iron Calcium The abundance in the earth's crust of all the elements Sodium is given in Figures 1 and 2. Several points deserve Potassium attention. First, as pointed out by W. D. Harkins Magnesium Hydrogen over 30 years ago, it is apparent that most of the earth's Titanium crust is composed of elements of low atomic number. Chlorine Second, the elements of even atomic number are far Phosphorus more abundant than those of odd atomic number. 99.5 Third, as a general rulecalled the Harkins-Oddo or a From ANDERSON, J. S., J . Prm. Roy. Sm. N . S . Wales, 76, even-odd r u l e a n element of odd atomic number is 329-45 (1943). For other estimates, see FLEISCHER, M., "Recent estimates of the abundances of the elements in the earth's crust," less abundant than the two adjacent elements of even U. S. Geol. Survey Circular No. 285 (1953). atomic number. Exceptions to this rule are evident in Figures 1 and 2, and some of these will be discussed review by noting that in the last few years important later, but the rule does hold for most of the elements. There is little doubt that this rule and, in fact, the research in this field has been resumed in the United entire pattern of the abundance of the elements reflect States. The first comprehensive book on geochemislaws, not yet fully understood, that govern the way in try6 to be published in English since the fifth edition of Clarke and also the first textbook of geochemistry in which neutrons, mesons, protons, and electrons are English7 have appeared during the past few years. and can be assembled to form the elements. Whoever Powerful stimuli have been the discovery of the im- explains the why of Figures 1 and 2 will be close to portance of traces of various elements to plants and ani- answering this most fundamental problem. Further mals and the interest of nuclear physicists in cosmic consideration of this subject and of the abundance of the isotopes is outside the scope of this paper, but it phenomena. may be mentioned that nuclear physicists have been ABUNDANCE OF ELEMENTS IN THE EARTH'S CRUST able to set up equations that reproduce in part the facts The percentages by weight of the 12 most abundant summarized in these figure^.^ A striking exception t o the even-odd rule is that the elements in the upper ten miles of the earth's crust are abundances given for helium, neon, argon, krypton, RANKAMA, K., AND TH. G. SAHAMA, "Geochemistry," Uniand xenon are very much lower-by a factor of ten versity of Chicago Press, Chicago, 1950. ' MASON,B., "Principles of Geochemistry," John Wiley & thousand to one million-than one might expect from the even-odd rule. As these are easeous elements that Sons. Inc.. New York. 1952. do not readily form compounds, it seems plausible to assume that these were lost from the molten crust of the earth to the atmosphere, and from there partly lost into space. This explanation is supported by TABLE 1 The Twelve Most Abundant Elements i n the Earth's C=uste (Including the Oceans and Atmosphere)
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10-.*
10.-
