GEOLOGICAL SURVEY RESEARCH 1 969 Chapter B

GEOLOGI'CAL SURVEY PROFESSIONAL PAPER 650-8

Scientific notes and summaries of investigations in , , and related fields

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON: 1969 DEPARTMENT OF THE INTERIOR WALTER J. HICKEL, Secretary

GEOLOGICAL SURVEY William T. Pecora, Director

For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 - Price $2.75 CONTENTS

GEOLOGIC STUDIES

Petrology and mineralogy page Origin of some amphibolites in western North Carolina, by A. E. Nelson ...... Lawsonite blueschist from north-central Oregon, by D. A. Swanson------

Oligocene rhyolite in the Denver basin, Colorado, by G. A. Izett, G. R. Scott, and J. D. Obradovich ------.------A historic eruption of Mount Rainier, Wash., by D. R. Mullineaux, R. S. Sigafoos, and E. L. Hendricks ------..------Tuffaceous epiclastic breccia and sandstone near Hahns Peak, Colo., and their genetic implications, by Kenneth Seger- strom and S. H. Kirby------Ordovician bedded chert, argillite, and shale of the Cordilleran eugeosyncline in Nevada and Idaho, by K. B. Ketner-- Notes on the geology and paleohydrology of the Boulder City pluton, southern Nevada, by R. E. Anderson------..---- Accessory sphene from hybrid rocks of the Mount Wheeler mine area, Nevada, by D. E. Lee, R. E. Mays, R. E. Van Loenen, and H. J. Rose, Jr-----_------_------Microindentation hardness of members of the ludwigite-vonsenite series, by B. F. Leonard--_ ------Paleontology and stratigraphy Larger fossil mammals and mylagaulid rodents from the Troublesome Formation (Miocene) of Colorado, by G. E. Lewis- 53 Age and stratigraphic relations of the Tepee Trail and Wiggins Formations, northwestern Wyoming, by W. L. Rohrer andJ. D. Obradovich------_------..------.-- 57 New evidence on age relationships of possible Eocene rocks in southwestern North Dakota, by N. M. Denson------63 Economic geokgy White clay deposits near Mount Holly Springs, Cumberland County, Pa., by J. W. Hosterman ------66 Possible exploration targets for uranium deposits, south end of the Uravan mineral belt, Colorado-Utah, by D. R. Shawe- 73

Hydraulic equivalence of minerals with a consideration of the reentrainment process, by N. S. Grigg and R. E. Rathbun- 77 Geochronology of ash deposits on Amchitka Island, Alaska, by H. T. Shacklette and Meyer Rubin------81 The ages of three uranium minerals, Mojave Desert, Calif., by D. F. Hewett, Jerome Stone, and L. R. Stieff------84 The time interval between stabilization of alpine glacial deposits and establishment of tree seedlings, by R. S. Sigafoos and E. L. Hendricks ...... 89 Distribution of mercury in the Navajo Sandstone, Colorado Plateau region, by R. A. Cadigan------94 Distribution of minor elements in samples of biotite from igneous rocks, by T. G. Lovering ...... 101 Rock mechanics Subsurface deformation resulting from missile impact, by H. J. Moore----_-_ -_------_-_-_...... 107 Geophysics

Hawaiian seismic events during 1966, by R. Y. Koyanagi------_ ------113 Seismic events originating at the Atomic Energy Commission's Nevada Test Site, by H. L. Krivoy and C. E. Mears--- 117 Seismic investigations on Cape Cod, Martha's Vineyard, and Nantucket, Mass., and a topographic map of the basement surface from Cape Cod Bay to the islands, by R. N. Oldale ...... - 122 Analytical methods Microanalysis with the X-ray milliprobe, by H. J. Rose, Jr., R. P. Christian, J. R. Lindsay, and R. R. Larson------128 The direct microdetermination of silicon and aluminum in silicate minerals, by Robert Meyrowitz------136 Rapid determination of powder density of rocks by a sink-float technique, by Leonard Shapiro.. ------140 A transistorized emission regulator for gas-source mass spectrometry, by E. E. Wilson and J. S. Stacey------143 111 IV CONTENTS

Cartographic techniques Page Contour finder-Inexpensive device for rapid, objective contouring, by S. P. Schweinfurth------..------B147

HYDROLOGIC STUDIES Ground water Development of ground-water supplies on the Pajarito Plateau, Los Alamos County, N. Mex., by W. D. Purtymun and J. B. Cooper------..------149 Occurrence and movement of ground water in the Brunswick Shale at a site near Trenton, N.J., by John Vecchioli, L. D. Carswell, and H. F. Kssabach ...... 154 Correlation of carbonate rock units in northwest Ohio by natural gamma logging, by S. E. Norris and R. E. Fidler---- 158 Application of Poisson distribution to flood series, by P. H. Carrigan, Jr------_------162 Reduction of fluorescence of two tracer dyes by contact with a fine sediment, by C. H. Scott, V. W. Norman, and F. K.

Relation between surface water and ground water Effects of reservoir filling on a buried of glacial origin in Campbell County, S. Dak., by N. C. Koch------169 Quality of water Temperature analysis of a stream, by M. R. Collings...... -- -- 174 Geochemistry of water The Gibbs free energies of substances in the system Fe-02-HzO-COz at 25OC, by Donald Langmuir------.. 180 The sources of carbon dioxide in the zone of aeration of the Bandelier Tuff, near Los Alamos, N. Mex., by J. L. Kunkler-- 185 Coastal geohydrology Measurement of water flow and suspended-sediment load, Bolinas Lagoon, Bolinas, Calif., by J. R. Ritter------189 Soil moisture Soil-moisture losses in the upper three inches of soil, Cibecue Ridge, Aria., by M. R. Collings ------..------194

INDEXES GEOLOGICAL SURVEY RESEARCH 1969

This collection of 40 short papers is the first published chapter of "Geological Survey Research 1969." The papers report on scientific and economic results of current work by members of the Conservation, Geologic, and Water Resources Divisions of the U.S. Geological Survey. Chapter A, to be published later in the year, will present a summary of significant results of work done during fiscal year 1969, together with lists of investigations in progress, reports published, cooperating agencies, and Geological Survey offices. "Geological Survey Research 1969" is the tenth volume of the annual series Geological Survey Research. The nine volumes already published are listed below, with their series designations.

Geological Survey Research 1960-Prof. Paper 400 Geological Survey Research 1961-Prof. Paper 424 Geological Survey Rmearch 1962-Prof. Paper 450 Geological Survey Research 1963-Prof. Paper 475 Geological Survey Research 196GProf. Paper 501 Geological Survey Research 1965-Prof. Paper 525 Geological Survey Research 1966Yrof. Paper 550 Geological Survey Research 1967-Prof. Paper 575 Geological Survey Research 1968-Prof. Paper 600 GEOLOGICAL SURVEY RESEARCH 1969

RADIOCARBON DATING OF ASH DEPOSITS ON AMCHITKA ISLAND, ALASKA

By HANSFORD T. SHACKLETTE and MEYER RUBIN, Denver, Colo., Washington, D.C.

Work done in cooperation with the Advanced Research Projects Agency, U.S. Depwtment of' Defertee

Ahtract.-Peat deposi,tson the ,tableland of Amchitka Ieland mine the absolute and relative rates of. -peat deposition contain 3 layem of volcanic ash, each about 1-2 in thick- under different types of vegetation. From these rates ness. Radiocarbon dates Of discrete *Iant stems from these ash the length of time that the present vegetation mantle layers indicate that the age of the uppermost ash deposit ia 725 k260 years B.P. The two lower a& layem lie about 7 ern apart; existed On this &land may be estimated. the average of ltheir dates is 1,845 years B.P. The amom* of Recently combined carbon is continuously introduceci Peat above the ash layem indicates that avemnage mites of ac- into peat deposits through roots which grow downward cumdation are Om2 cm/yr for to mucky in successive seasons; therefore, samples that repre- peat, and 0.052 cm/yr for the more completely heedand compacted peat The tobl depth this sent the total material in the deposit are unsatisfactory tion (2.8 m) indie&- ~t about 3,400 yeam wa.s reqmfor for radiocarbon dating of the peat. In the peat profile the formation of this deposit. It is estimated, therefore, that that was studied, living roots were found 0.5 m above this ableland has borne a v%*tion mantle no longer than the bottom of the thick peat deposit. In addition, down- 4,000 yeare. ward migration of humic substances probably distrib- utes recently combined atmospheric carbon khrough- Amohitka Island, the largest in the Rat Island group out the deposit. Carson (1968, p. 16) stated, LLAsis (Aleutian Islands) has an area of 114.1 square miles well known, peats are among the more difficult organic (Coats, 1956, P. 86) , one-half of which is tableland of materials upon which to base C-14 interpretations. An- several segments at different altitudes ranging from nual dilution produces material of composite age, in about 135 to 500 feet (Powers and others, 1960, p. 526). both surface and buried mats." Dates of peat samples, 'These segments are largely mantled with a mat of liv- therefore, ordinarily represent average ages of the or- ing heath and bog vegetation which overlies deposits ganic matter in the samples, and are more recent than of peat and muck that are as much as 3 meters thick. the age of the oldest material in the sample. Three layers of ash, each about 1-2 centimeters thick, AcknowZedgmnts.-This study was supported in can be recognized in profiles of this organic deposit. part by Advanced Research Projects Agency, Depart- The vertical distance between the ash layers is pre- ment of Defense, under Order No. 938. James A. Erd- sumed to relate to the rate of peat deposition at a par- man assisted in the collection and preparation of the ticular sits. Perennially frozen ground (permafrost) samples. has not been reported in the Aleutian Islands, and no MATERIALS AND METHODS effects of cryogenic processes were evident in these peat deposits on Amchitka Island.. There have been no vol- Trenching on Amchitka Island at an altitude of can- on this island since its emergence from the sea, about 125 feet exposed the profile of a peat deposit 2.8 which was inferred by Powers, Coats, and Nelson m thick which afforded an exceptionally good oppor- (1960, p. 550) to have been before late time. tunity to obtain, from the ash layers within the deposit, The dating of these ash deposits allows one to deter- samples of organic matter that were relatively free of B81 U.S. GEOL. SURVEY PROF. PAPER WB. PAGES BB1-BE3 B82 GEOCHRONOLOGY

CUMULATIVE THICKNESS L~v~ngvegetation measure of the rate of humified peat deposition that wrts mat obtained. RESULTS PEAT ACCUMULATION 140 cm of peat-0.2 cm/yr The age of the plant material in the upper ash layer for 725 years Upper ash layer ,(sample W-2131) (W-2131, fig. 1) was found to be 725+250 years B.P. (before present). The materials in the middle layer (W-2130) and in the lower layer (W-2129) were Lower ash layer (sample W-2129) 1,950-c-250 and 1,740+-250 years B.P., respectively. 0.87 These two latter dates are averaged as 1,845 years 0.80 for 1.560(?) years B.P. in figure 1.

3.405 years B.P. The top of the upper ash layer was 1.4 m below the ground surface, and the peat in the part of the profile abow the ash layer was reddish brown and fibrous at upper levels, grading to dark-brown humified material FIGUBE1.-Profile of a peat deposit on Amchitka Island, (muck) just above the ash layer. This peat had ac- Alaska, showing the location and dates of the ash layers and the computed rates of peat deposition. cumulated at the approximate average rate of 0.2 cen- timeters/year. This rate of accumulation agrees well recent carbon contamination (fig. 1). This profile was with that of peat in the vicinity of Fairbanks, Alaska, of a peat composed principally of sedges (Carex Zyng- that was given by Heilman (1968, p. 336) as 0.25-0.38 bymi(?)and others), with some heath plants (mostly cm/yr. Carson (1968, p. 17) reported radiocarbon ages crowberry, Empetrum nigw) also present. The sedge of surface peats from the Barrow, Alaska, region to and crowberry stems were preserved as discrete plant range from 4,280k160 years B.P. for the bottom layer organs that could be separated from the humified struc- of peat that was 10 inches thick to 395+150 years B.P. tureless mucky material and living plant roots that for peat 6 inches thick. An examination of the history made up the greater part of the total deposit. These of these peat deposits suggests that reliable rates of stems grow only on or just above the surface of the peat deposition in this region cannot be inferred from peat; for this reason it is known that the ash falls and these data. the plant tissues imbedded in them are contempora- The more completely humified and compacted peat neous. between the upper ash layer and the two lower ash In February 1968, samples of these plant stems were layers accumulated in approximately 1,100 years, or at removed by hand sorting from the 3 ash layers, washed an average rate of about 0.052 cm/yr. The contrast be- to reduce gross contamination from humic materials, tween rates of accumulation of peat that is fibrous to sealed in polyethylene bags, and in March 1968, sent mucky, and that of more completely humified muck, to the U.S. Geological Survey's radiocarbon laboratory gives some concept of the degree of compaction and the in Washington, D.C., for further processing and dat- loss of organic constituents by decomposition and ing. Pretreatment of the stems was limited to a wash leaching in lower layers of a peat deposit in the Aleu- in a warm dilute HC1 solution in order to remove car- tian Islands climate, if it is assumed that the deposi- bonates. The usual rigorous treatment in boiling acid tion of organic matter on the ground surface occurred and alkali was eliminated because of the small size of at a rather uniform rate. the samples. The samples were then converted to acety- About 80 cm of humified peat lay below the lower lene gas and counted for 1 day in each of two propor- ash layer in the profile. If this layer of peat accum- tional counters. ulated at the same rate'as that described above (0.052 It should be noted that the two lower ash layers cm/yr), approximately 1,560 years was required for (lower and middle layers, fig. 1) were located very near each other, that the plant parts which were this layer to form. Thus, the estimated age of the sampled did not lie entirely in one plane, and that at lowermost peat in the profile is about 3,400 years. It places it was impossible to determine to which ash seems likely, therefore, that the low plateaus of Am- layer a stem should be assigned. For these reasons it chitka Island have borne a vegetation mantle no longer probably is best to consider the two lower samples as than 4,000 years. one, and to average the dates of the two samples. The All profiles of the peat mantle that were examined time interval between the deposition of the upper and on the low plateaus contained the three ash layers. The the two lower ash layers is, therefore, the only reliable distance between the upper and the middle ash layers SHACRLETTE AND RUBIN B83 in peat that was formed under the crowberry-moss- these volcanic islands may have been the source of the lichen heath indicates that this peat accumulates at ash layers in the peat profile that was studied. abou't half the rate of that formed under sedge mead- ows. This difference in rate may be a measure of the difference in biomass productivity of the two plant Carson, C. E., 1968, Radiocarbon dating of lacustrine strands in communities, or it may only indicate that sedge-peat arctic Alaska: Arctic, v. 21, no. 1, p. 1226. deposits, because of their wetter habitat, are less Coats, R. R., 1956, Reconnaissance geology of some western affected by erosion and oxidation processes. Aleutian islands, Alaska: U.S. Geol. Survey Bull. 1028-E, p. 83-100. The source of the ash that formed the three strata Heilman, P. E., 1968, Relatiomhip of availability of phosphorus was not determined. These ash falls antedate tlle his- and cations to forest wccession and bog formation in in- torical record of volcai~icactivity in the Aleutian terior Alaska: Ecology, v. 49, no. 2, p. 331436. Islands that was reported by Powers (1958, p. 64-67). Powers, H. A., 1958, Alaska Peninsula-Aleutian Islande, p. 81- Recorded activity of volcailoes on Semisopocl~noi, 75 in Williams, Howel, ed., Landscapes of Alaska-their geologic evolution : Berkeley, California Univ. Press, 148 p. Little Sitkin, and ICiskn Islands, \vhich are about 36, Powers, H. A., CW,R. R., and Nelson, W. H., 1980, Geology 40, and 75 miles distant, respectively, from the study and submarine physiography of Amchitka Island, AlmIra : site on Amchitka Island, suggests that any or all of U.S. Geol. Survey Bull. 1028-P, p. 521-664.