edited by: MICHAELR. SLABAUGH Weber State College Ogden. Utah 84408
Chemistry and the Modern Prospector Thomas R. Neffi
The classic image of the mineral prospector as a grizzled eccentric who spends his time wandering through the hills leading his trusted burro is no longer valid, if indeed it ever were. Nowadays, the search for mineral deposits is more likely to involve a highly sophisticated team of experts who employ a diverse hag of technological tricks. One of the most important of these is a relatively new area of expertise known as ex~lorationeeochemistrv. Professionals in this field use the trace elements naturally present in rock, soil, water, and plants as indicators of valuahle mineral concentrations. In addition, such exotic techniques as the analysis of vapors present in soils may even by employed. Exploration geochemistry is really only an extension of a vractice commonlv used bv the traditional prospector. These and nuggets found when working sand and gravel.deposits along stream courses. To trace the gold to its source, samples were panned for "color," i.e., small flakes of gold. These samples were collected in a sequence progressively farther upstream away from the deposit being worked. As long as "colors" were seen in the pan, the prospector knew he was on the right track. By using trial and error, it was possible for a careful prospector to sometimes follow a line of colors up the twists, turns, and branches of a stream course to where the mother lode intersected the channel. Unfortunately, the trail
I The author who was on the faculty of Weber State College, Ogden, Utah, is deceased. Address all correspondence regarding this manuscript to the Feature Editor. Michael R. Slabaugh.
Figure 1.
Primary halo ( 1)
was commonly lost because the prospector had to rely on his panning skill, the strength of his vision, and the persistence of the string of colors. The earliest attempts a t geochemical prospecting in the late 1930's and 1940's were a simple extension of the "mother lode" search pattern. It was felt that if the flakes could not be seen then maybe they could be detected by chemical means in the stream sediments. Unfortunatelv, this does not work veni well metal bouncing down the stream channel. 1t was discovered,
Volume 58
Number 9
September 1981
699
however. ~. that other metals. that are reactive. would disverse to prrtr>pecti\.emin~.raldelwsit. ,\ir i w t r p ~ ~ ~ m n ton v i,I l 1 . 3 ~ rlymc hrliw~ityrare riwd t u d l w t w r m d ~ ~ t ~ i ~by t t plant ttl transpiration. These aerosols have been shown to contain organometallic molecules with the amount of metal contained heing proportional to the amount of metal in the soil. The following elements have been detected in terpine-derived, organometallic aerosols emitted from conifers: Li, V, Cr, Co, N i Cu, Zn, As,Mo, Ag, Pb, Bi, Cd, Sn, Sb, and Ba. In addition to the aerosols, fine particulate matter carried off the ground surface by air currents may be sampled also. As new techniaues such as airborne eeochemistrv are de-
other firm even if they change employment.
are vital since new deposits are becoming increasingly difficult to find and minerals form a basic foundation uoon which our modern technological society is built.
Vapor Surveys Gases are exuded from many different types of mineral deposits to form a vapor halo in the soil overlying the deposit. Recentlv a considerable amount of research has been directed toward the detection of vapor halos. However, a t the present time only a few techniques and specialized pieces of equipment have been perfected beyond the purely research stages of development and are, therefore, unusable for routine sur-
Literature Cited (11 I.evinsun, A. A . "Intioductiun f a Exploration CmchernisLry." Applied Publishing. Cslgary, 1 9 7 4 , ~612. . (21 1.ouering.T. G.. U. S. Uool Survey Pro/ Papei.710. (19721. (3) Taylor,S.R., Ceochim et Cosmochim. Acto.,28,1273 (1964). (4) Tay1or.S. R.,PhysiiaondChem. ofthaEarth,6,135 (19661. ( 5 ) Sarby, J. D.. Re". Pure. Appl Chem., 19,131 (19691. (6) Ward, F. N., Lakin, H. W.. and Canney. F. C., et d.,U S . Ceol Suroay Ruil., 1152 (19631. (7) Sa~quis,M.. and Mickey. C. D.. J.CHEM.EUUC 57.886 (19801
Volume 58 Number 9
Seotember 1981
703
