UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY Center of Astrogeology 601 East Cedar Avenue Flagstaff, Arizona 86001 November 30, 1968 Memorandum To Assistant Chief Geologist for Engineering Geology From Deputy Assistant Chief Geologist for Astrogeology Subject: Monthly Report for Director and Secretary HIGHLIGHTS AND NOTEWORTHY RESULTS Astrogeologic Studies Branch Lunar and Planetary Geologic Mapping R. E. Eggleton noted the existence of a possible very ancient multi-ring basin about 600 km in diameter centered near 175 0 E, 15° N on the lunar far side. A small patch of mare material, which is very scarce on this part of the lunar surface; some pitted plains material; and two uplifted and fractured crater floors--all located near the basin center--suggest that young, possibly dense, plutons concentrated under the basin may account for a gravity high postulated by Carl Sagan and his associates at Cornell University, Ithaca, New York, to exist near the center of the lunar far side. A meeting was held in Flagstaff, Arizona, on November 26, with M. E. Davies, Rand Corporation, Santa Monica, California, to discuss Mars mapping on materials to be acquired during the Mars Mariner 1969 flyby. W. T. Borgeson, S. S. C. Wu, D. W. G. Arthur, R. M. Batson, and Harold Masursky participated. The following investigators have been appointed for the Mars Mariner 1971 programs by the National Aeronautics and Space Administration: Harold Masursky, Principal Investigator J. F. McCauley, D. E. Wilhelms, D. J. Milton, R. L. Wildey, and W. T. Borgeson, Co-Investigators In addition, TV teams composed of five principal investigators and 27 co-investigators have been organized along discipline lines: Team Leader Harold Masursky u.s. Geological Survey Flagstaff, Arizona Geology Variable Features Exobiology J. F. McCauley Carl Sagan Joshua Lederberg U.S. Geological Survey Cornell University Stanford University Menlo Park, California Ithaca, New York Palo Alto, California Hardware--Data Processing Geodesy--Cartography B. C. Murray Gerard de Vaucouleurs California Institute of University of Texas Technology Austin, Texas Pasadena, California Apollo Site Investigations J. W. Dietrich, Manned Spacecraft Center, Houston, Texas, D. E. Wilhelms and Harold Masursky, U.S. Geological Survey, gave a briefing at Cape Kennedy, Florida, on photography to be acquired on the Apollo VIII mission in December. The briefings were given to W. A. Anders, LM pilot of the prime crew, and F. W. Raise, Jr., LM pilot of the backup crew. Revised geologic maps, including revised explanations and texts, of the five prime Apollo landing sites, II P-2, II P-6, II P-8, II P-l3, and III P-ll, at scales of 1:100,000 and 1:25,000 have been completed. The ten maps are currently being checked for consistency and minor errors. They will be transmitted to Manned Spacecraft Center, Houston, Texas, next month. Lunar Engineering Geology R. J. Pike reports that under the direction of F. B. Sower, Computations Branch, Flagstaff, Arizona, a unified system for photoclinometric analysis of lunar terrain samples is being set up on the IBM 360/65. Complete terrain statistics, power spectral density functions, profile plots, and card outputs, if desired, will be obtained more quickly and conven­ iently than when these various results were derived piecemeal. Substan­ tial savings in computer time and man-hours will be realized. G. I. Selner, Computations Branch, Flagstaff, Arizona, has made the necessary modifi­ cations to the Langley II photoclinometric program. D. K. McMacken has modified the slope and curvature subroutines of the Wilson terrain analysis computer program. For each sample of lunar 2 terrain, the reV~Slons now yield the desired statistics at 20 different sample intervals and print out six cumulative frequency curves. A measure of gross topographic texture, "topographic grain," has been added to the Wilson program, and an analysis of slope length (distance between slope reversals) is being programmed in as well. R. J. Pike reports that suitably modified, cumulative fr.equency distri­ butions of lunar slopes exhibit a useful property also present in terrestrial slope distributions. When each slope value in a given lunar distribution is divided by the mean slope value, the resulting plot of cumulative frequency against percentage-of-mean-slope is identical to similarly derived curves for any other lunar slope distri­ bution, regardless of the nature of the terrain. Such a curve can be used to predict slope frequency distributions for any type of lunar terrain, once the mean slope value has been determined. The latter value can be estimated for lunar locales poorly suited to detailed photoclinometric analysis at any desired sample interval, from means derived by L. C. Rowan and J. F. McCauley (1966, Lunar Orbiter--Image analysis report, U.S. Geol. Survey open-file report) and J. F. McCauley (1964, Terrain analysis of the lunar equatorial belt, U.S. Geo1. Survey open-file report) at a sample interval of 0.6 km. While this method produces slope-frequency distributions, it does not generate the data required for curvature or power spectral density analysis of rough and (or) steep lunar topography. Investigation is continuing into possible techniques that will enable photoclinometric data to be used for the description of these difficult terrains. Imagery from Lunar Orbiter missions IV and V is being evaluated for photoclinometric analysis at sample intervals greater than 1.0 meter. Cosmic Chemistry and Petrology As a member of the preliminary examination team, E. C. T. Chao partici­ pated in a lO-day simulation at the Lunar Receiving Laboratory at the Manned Spacecraft Center, Houston, Texas. Calibration of the interference microscope is nearing completion. A report for the first six months on NASA Contract T-754l2 concerning impact metamorphism of lunar materials prepared by E. C. T. Chao and J. A. Minkin has been submitted to the Manned Spacecraft Center, Houston, Texas. A demonstrator Mark II, Jarrell-Ash microfocus x-ray unit was installed this month and is being checked out. This unit will be used for future study of shocked material by small angle x-ray scattering and Lang technique. Impact Investigations D. J. Milton reports that geologic mapping of the central zone of Gosses Bluff, Australia, is complete and all shatter cone measurements have been obtained. An Australian Bureau of Mineral Resources gravity 3 party is now in the field, measuring at stations on a 1/2 mile grid (1/4 mile in the center) in a 15 mile square. The work began late in the field season and it will be finished next year. T. W. Offield a.nd H.. A. Pohn report that maps made from subsurface data provided by the Missouri Geological Survey show that the Decatur­ ville structure lies on a distinct north-south linear structural high which connects with the Proctor anticline north of the structure. Moreover, the Decaturville structure is located at the intersection of this line with faint east-northeast and east-southeast linear trends in the subsurface configuration. The east-southeast line, if extended, matches a line drawn to connect several explosion structures from Illinois to Kansas (Snyder and Gerdemann, Am. Jour. of Sci., 1965, p. 465-493). D. J. Roddy reports that asymmetric extensions in the air shockwave and fireball produced by the detonation of the SOO-ton TNT surface sphere (Defence Research Establishment, Alberta, Canada) have been correlated in position with asymmetric extensions in the crater ray ejecta pattern and foldback. These correlations indicate initial inhomogeneities in the fireball and in the transmission of the shockwave to the ground. Thus, the inhomogeneities in the fireball were primarily responsible for the patterns of rays in the ejecta and of distribution of the foldback. No base surge deposits were positively identified. A series of x-ray fluorescence analyses have been completed on the fused fragments formed at the crater and each appears to have been derived from the upper 1 to 2 meters of soil that was in the region below the TNT charge. Petrographic studies have confirmed that thermal effects ranged from baking and incipient surface fusion of individual soil fragments to complete fusion and intense vesiculation. Both the chemical composition and petrography indicate similarities with impactite material. A series of disequilibrium high-temperature fusion experiments have been completed on undisturbed soil fragments; minimum fusion temperatures indicated by these experiments suggest soil disequilibrium temperatures at the time of detonation were in excess of 1100°C and probably on the order of l500°C. Further tests are in progress" Geologic and topographic maps of this crater are being prepared. Impact Metamorphism Project o. B. James and E. C. T. Chao made an extensive collection of granodio­ rite, quartz monzonite, quartzite and volcanic tuffs exhibiting various degrees of shock from the Sedan 100 kiloton event at the Nevada Test Site. The study of shocked igneous rocks is of interest to the lunar sample analysis project. 4 D. E. Wilhelms and Heinrich Schiemann of West Germany's Zweites Fernsehen filmed a television program, in German, dealing with lunar geology. The program will be shown in Germany during the first manned circumlunar flight. 5 Surface Planetary Exploration Branch Apollo Investigations Mission Planning.--T. N. V. Karlstrom, Chief, Apollo Mission Planning project, chaired a meeting November 15, in Flagstaff, Arizona, of a working group on the quality of large scale photomosaic~ for Early Apollo Data Package maps. The group, made up of representatives from the Department of Defense, NASA, Manned Spacecraft Center, Houston, Texas, and the u.s. Geological Survey (1) reviewed the technical proce­ dures required to produce high quality bases from Orbiter photography for operations maps and scientific maps to be taken on Early Apollo missions, and (2) established a schedule of interagency responsibilities that will meet the deadline for NASA, Manned Spacecraft Center produc- tion of Data Package maps in time for their use on the first Apollo landing mission.