BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 4 9, PP. 5 2 5 - 5 3 8 , 4 FIGS. APRIL 1, 1 93 8 RADIOACTIVITY OF THE THERMAL WATERS, GASES, AND DEPOSITS OF YELLOWSTONE NATIONAL PARK BY HERMAN SCHLUNDT * AND GERALD F. BRECKENRIDGE CONTENTS Page Introduction........................................................................................................................ 525 Scope of the investigation................................................................................................. 526 Apparatus................................................................................................................... .. 526 Methods of procedure......................................................................................................... 528 Examination of gases.................................................................................................. 528 In the field laboratory........................................................................................ 528 In the field........................................................................................................... 529 Examination of water samples.................................................................................. 530 Examination of solids................................................................................................ 531 Radioactivity...................................................................................................................... 531 Gases.............; . ..................................................................................................... 531 Waters......................................................................................................................... 532 Solids........................................................................................................................... 535 At Thermopolis, Wyoming............................... ...................................................... 535 Summary and conclusions................................................................................................ 537 Works to which reference is made................................................................................... 538 ILLUSTRATIONS Figure Page 1. Wulf quartz fiber electroscope........................................................................................... 527 2. Apparatus for collecting gas samples....................................................................... 528 3. Arrangement of apparatus for field measurements................................................ 530 4. Arrangement of apparatus for measurement of radium content of water samples. 531 INTRODUCTION The radioactive properties of the waters of Yellowstone National Park were first studied in 1906 by Schlundt and Moore (1909). With cali­ brated field instruments they made a rather complete study of the radio­ activity of the waters of the Park. In the summer of 1936, Schlundt and Breckenridge again determined the radioactive properties of these waters, with modern standard instru­ ments. They were assisted in this work by two graduate students of the University of Missouri, Bradley Offutt and Ross Heinrich. * Dr. Schlundt died December 30, 1937. (525) Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/49/4/525/3415520/BUL49_4-0525.pdf by guest on 02 October 2021 526 SCHLUNDT AND BBECK.ENRIDGE— RADIOACTIVITY IN YELLOWSTONE The^ Geological Society of America defrayed the greater portion of the expense connected with the field tests of this investigation by means of a grant from the Penrose Bequest. The University of Missouri loaned most of the scientific apparatus used in the field tests, and the determina­ tion of radium present in spring deposits and rock samples was made in the chemical laboratories of the University of Missouri. SCOPE OF THE INVESTIGATION The field tests extended over a period of almost two months, during which time the principal basins of thermal activity were visited. The spring waters examined include the different types found in the Park. Many springs evolve gases, and the radioactivity of several gases from representative springs was determined. The pH of the spring waters was also determined. Due to a broken glass electrode and the time required to replace it, the pH determination for the springs studied is not com­ plete. Where the temperature of the springs is recorded, this measure­ ment was made with a “maximum” thermometer. APPARATUS The determinations of radioactivity were all made by the electrical method. A Wulf quartz fiber electroscope (Fig. 1) fitted with an ioniza­ tion chamber of 1175 cc. capacity served for the field measurements of both water and gas samples. The circulation method was used for the standardization of the electroscope. The stock solution used for the standardization is known as the University of Missouri Standard and was prepared by H. H. Barker (1923, p. 54). One cc. of this stock solu­ tion contains 7.136 x 10“10 grams of radium element, and 20 cc. of this solution was diluted to one liter in bottles of about 1050-cc. capacity. The samples were dè-emànated, and the bottles were sealed and kept sealed for a known period of time. Results of the determination of the-calibration constant are shown in Table 1. The calibration constant is expressed in grams of radium neces­ sary to produce a net drift in the electroscope leaf of one division per second. T a b le 1.—Standardizing record oj electroscope R a d iu m p e r d i v i s i o n p e r Number Place and Date second (grams x 10 ~9) 1. Yellowstone P a rk , July 9, 1936............. .,.......................... 18.5 2. Yellowstone Park, July 20, 1936....................................... 17.4 3. Yellowstone Park, July 22, 1936.............................. ......... 21.4 4. Yellowstone Park, August 8, 1932.................................... 17.0 5. Columbia, Missouri, June 11, 1936.................... ................ 14.7, Due to the difference in atmospheric pressure between Columbia, Missouri, and the Yellowstone National Park, the value of the calibra- Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/49/4/525/3415520/BUL49_4-0525.pdf by guest on 02 October 2021 APPARATUS 5 2 7 I * £ ' 1 <---------------------- T t ---------------------- >i i l tion constant obtained in the Park should be higher than that obtained in Columbia. According to Lester (1917, p. 225-232) the value of the calibration constant should be about 12 percent higher in the Park than in Columbia. By adding 12 percent to the value obtained in Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/49/4/525/3415520/BUL49_4-0525.pdf by guest on 02 October 2021 528 SCHLUNDT AND BRECKENRIDGE-RADIOACTIVITY IN YELLOWSTONE Columbia, a value of 16.7 x 10-9 is obtained. The values obtained in Yellowstone Park during the summer of 1936 are probably too high. The standard solutions were de-emanated and sealed June 30, 1936. During the trip to the Park the seals of the bottles were broken and the solutions were again de-emanated and resealed. A small portion of the solutions -- -, FIGURE 2.-Apparatus for collecting gas samples was lost, and this would account for a high calibration constant. For calculations of all results in this report, the value of 17 x 10-9 was taken as the constant of the electroscope. METHODS OF PROCEDURE EXAMINATION OF GASES In the Fieid Laboratory.-For the majority of gas samples, the gas to be examined was collected in a storage jar and the radium activity later determined in the field laboratory. The method of collecting and storing the gas samples is illustrated in Figure 2. The gas was first collected in the container (A), an open can of about one liter capacity, to which was soldered a small metal tube. (A glass container was sometimes used.) The container was connected to the hand bellows (B) by means of rubber tubing, and the hand bellows, in turn, was connected to the storage jar (C), a glass jar of about two liters capacity. The method of collecting the gas was as follows: the storage jar (C) was filled with water and then connected with the rest of the system. The gas container (A) was then lowered into the spring at a point where the concentration of gas bubbles was large, and all the air in the container was replaced by water. Gas bubbles from the spring were then allowed to displace the water in the container, and when the container was about two-thirds full, the gas was pumped into the storage jar by means of the hand bellows. The Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/49/4/525/3415520/BUL49_4-0525.pdf by guest on 02 October 2021 METHODS OP PROCEDURE 529 displaced water was removed at (E ). This process was repeated until the storage jar was filled with the gas to be examined. The jar was then made air-tight, by closing the screw clamps (E) and (D). In some springs the majority of the gas bubbles escape in the central part of the spring, and in these a pole was attached to the container (¿4) in order to reach the gas. The gas samples were measured in the field laboratory about five or six hours after they had been collected. Before introducing the gas into the electroscope, the natural drift of the electroscope leaf was deter­ mined. By an aspiration method, the gas to be examined was introduced into the ionization chamber at the lower stop-cock, the upper stock-cock being open to the atmosphere. Before entering the ionization chamber,