Devoted to the Study of Earth’s Vol. 28 No. 3 fall 2009 SELENOLOGY The Journal of The American Lunar Society Selenology Vol. 28 No. 3 - Fall 2009

The official journal of the American Lunar Society, an organization devoted to the observation and discovery of the earth’s moon TABLE OF CONTENTS:

A Study About A Lunar Dome In Paulus Putredinis ...... 2

The Photography Of Richard Hill...... 7

From The Papers ...... 10

COVER: Paulus Putredinis photographed by G. Tarsoudis on March 14, 2008 at 19:43 UT using a using a 250 mm Newtonian telescope

Selenology, Vol. 28 No. 3, Fall 2009. A publication of the American Lunar Society. President: Steve Boint; Vice President: Francis Graham; Editors: Steve Boint, Raffaello Lena. Web site: http://eselenology.offworldventures.com/ http://amlunsoc.org/ (currently under construction)

Copyright © 2009 by the American Lunar Society and individual authors; all rights reserved.

Send manuscripts, general observations, photographs, drawings and other correspondence to: Steve Boint, Pres. ALS, 1807 S. Spring Ave., Sioux Falls, SD 57105 E-mail: [email protected] Send changes of address to Andrew Martin at [email protected] If you don’t have e-mail, send them to Steve Boint To subscribe to Selenology, send $15 US to Andrew Martin, 722 Mapleton Rd, Rockville, MD 20850 Make checks payable to: American Lunar Society Page 2 Selenology Vol. 28 No.3 Fall 2009 Page 3 A Study about a lunar dome in By Raffaello Lena, Christian Wöhler and George Tarsoudis Geologic Lunar Research (GLR) group

Abstract duced the Imbrium basin, a multi-ring structure that In this study we examine a lunar dome located in formed 3.85 billion years ago. The outermost ring Palus Putredinis, termed Putredinis 1. Its diameter is apparent as the mountain range called Montes corresponds to 7.0±0.5 km and its height to 90±10 Apenninus. Multiple inner rings also formed dur- m, resulting in a flank slope of 1.47° and an edifice ing the impact event, though only the highest points volume of 1.78 km³. According to the inferred spec- of these are now visible above the later-forming tral, morphometric, and rheologic properties, the lavas. Examples of such peaks in the north of Mare dome Putredinis 1 belongs to class C2 in the GLR Imbrium are Montes Spitzbergen and Mons Piton classification scheme of effusive domes. (Wilhelms, 1987). The oldest visible Imbrium lavas are probably those of the lighter albedo plains units 1.Introduction inside the main Imbrium ring. They occur between The mare basins were formed by large impacts and , in a region which led to large-scale fracturing of the lunar crust. called the Apennine Bench Formation, and are The fractures are commonly interpreted as the con- notable for their roughness, lighter color, tectonic duits along which basaltic magmas ascended to the features (grabens) and domes. surface. Lunar domes have formed as effusive shield- Palus Putredinis is a lava-flooded plain bounded like volcanoes or possibly also as laccoliths if the by the crater Autolycus to the north and the hills magma remained subsurface (Head and Gifford, of the Montes Archimedes to the west. The oldest 1980; Wöhler and Lena, 2009). A laccolith is a materials visible are those from the impact that pro- magma intrusion, without effusive process. The

Figure 1: the dome in an image taken by R. Lena on April 2, 2009, at 19:42 UT using a 180 mm Maksutov Figure 2: taken by G. Tarsoudis on March 14, 2008 at 19:43 UT using a using a 250 mm Cassegrain telescope. Newtonian telescope. Page 4 Selenology Vol. 28 No.3 Fall 2009 Page 5 pressure of the magma is high enough that the over- Albedo at 750 nm is an indicator of variations in soil ologic model by Wilson and Head (2003) estimates 2, which belongs to class B1, while short durations lying strata are forced upward, giving the laccolith composition, maturity, particle size, and viewing the yield strength τ (the pressure or stress that must of the effusion process result in lower and less volu- a dome or mushroom-like form with a generally geometry. The R415/R750 colour ratio is essentially be exceeded for the lava to flow) and the plastic minous edifices, as is the case for domes of class planar base. These domes are exceptionally large, a measure for the TiO2 content of mature basaltic viscosity η, yielding a measure for the fluidity of B2 such as the dome H7 near the crater Hortensius and most of them are associated with faults or linear soils, where high R415/R750 ratios correspond to the erupted lava, the effusion rate E (the lava vol- (Wöhler et al, 2006; Wöhler et al, 2007; Lena et al, rilles of presumably tensional origin. Due to the low high TiO2 content and vice versa (Charette et al., ume erupted per second) and the duration T of the 2007; Lena et al, 2008). profile of domes, Lunar Orbiter and Clementine 1974). However, for many lunar regions the relation effusion process. The computed values for τ, η, E, Wöhler et al. (2007) establish three rheologic images do not show domes very well, due to the between R /R ratio and TiO content displays and T are valid for domes that formed from a single groups of effusive lunar mare domes. The first group, 415 750 2 4 6 typically high solar angle on such images. Hence, a significant scatter (Gillis and Lucey, 2005). The flow unit (monogenetic volcanoes). According to R1, is characterised by lava viscosities of 10 –10 -5 -3 as part of our program of observing and cataloguing R950/R750 colour ratio is related to the strength of the model by Wilson and Head (2003), the yield Pa s, magma rise speeds of 10 –10 m/s, dike lunar domes, we have used high resolution telescop- the mafic absorption band, representing a measure strength of the dome-forming lava corresponds to widths around 10–30 m, and dike lengths between ic CCD images acquired under oblique illumination of the FeO content of the soil and is also sensitive to τ = 2400 Pa and about 30 and 200 conditions. the optical maturity of mare and highland materials the viscosity to η km. Rheologic 4 The Consolidated Lunar Dome Catalogue CLDC (Lucey et al. 1998). = 8.1 x 10 Pa s. group R2 is (Lena and Wöhler, 2008) contains all lunar domes The lava erupted c h a r a c t e r i s e d which have been studied in detail by the GLR group 3. Telescopic CCD images, spectral, morphomet- at an effusion by low lava vis- and for which reasonably accurate morphometric ric, and rheologic properties rate of 107 m3/s cosities between properties could be determined. The shallow dome Putredinis 1 was detected in over a period 102 and 104 Pa In this article we report measurements and include the images shown in Figs. 1-2. Figure 1 displays the of time of 0.53 s, fast magma CCD images of a lunar dome located at latitude dome in an image taken by R. Lena on April 2, 2009, years (about 28 ascent (U > 10-3 26.30°N and longitude 1.44°W in Palus Putredinis, at 19:42 UT using a 180 mm Maksutov Cassegrain weeks). To esti- m s-1), narrow which we have termed Putredinis 1. telescope. Another image, shown in Fig. 2, was mate the magma (W = 1–4 m) and taken by G. Tarsoudis on March 14, 2008 at 19:43 rise speed short (L = 7–20 2. Method and measurement UT using a using a 250 mm Newtonian telescope. and the feeder km) feeder dikes. For each of the observations, the local solar Further morphometric data were obtained by a dike geom- The third group, altitude and the Sun’s selenographic colongitude photoclinometric analysis. The dome height amounts etry, Wilson and R3, is made up were calculated using the LTVT software pack- to 90±10 m, yielding an average flank slope of Head (2003) Figure 3: A digital elevation map (DEM) of the region. of domes which age by Mosher and Bondo (2006) which requires a 1.47°±0.10°. The dome volume V was computed apply the dike formed from calibration of the images by identifying the precise by integrating the reconstructed 3D profile over an model by Rubin (1993). Dikes are rising vertical highly viscous lavas of 106–108 Pa s, ascending at selenographic coordinates of some landmarks on the area corresponding to a circular region of diameter sheets of magma. Rilles often form over rising ver- very low speeds of 10-6–10-5 m s-1 through broad image. This calibration was performed based on the D around the dome summit. A rough quantitative tical sheets of magma. A dike can reach the surface dikes of several tens to 200 m width and 100–200 UCLN 1994 list of control points. All images are measure for the shape of the dome is given by the and erupt, forming a dome. Based on the estimated km length. According to the rheologic properties oriented with north to the top and west to the left. form factor f = V/[πh(D/2)²] (where V=volume, lava viscosity and effusion rate, this approach inferred for the dome Putredinis 1, it clearly belongs -4 Further morphometric data were obtained by a h=height, and D=diameter), where we have f = 1/3 yields a magma rise speed of U = 1.1 x 10 m/s, a to rheologic group R1 like several domes in the photoclinometric analysis (Horn, 1989; Carlotto, for domes of conical shape, f = 1/2 for parabolic dike width of W = 15 m and a length of L = 67 km. Milichius/T. Mayer region and the well-known 1996; Wöhler et al., 2006; Lena et al., 2006 and shape, f = 1 for cylindrical shape, and intermedi- domes Cauchy τ and ω in Mare Tranquillitatis. references therein). We furthermore determined a ate values for hemispherical shape. For the dome 4. Result UVVIS five-band spectrum of the dome based on examined in this study, we thus obtain an edifice Based on the spectral and morphometric data Clementine imagery at the wavelengths of 415, volume of 1.78 km³ (f = 0.51). A digital elevation obtained in this study, the dome Putredinis 1 belongs References 750, 900, 950, and 1000 nm. The sample area was map (DEM) of the region is shown in Fig. 3. to class C2 in the scheme introduced by Wöhler et al. 2x2 km2. The reflectance values were derived rely- The Clementine UVVIS spectral data of the (2006) and later refined by Lena (2007). It consists [1] Carlotto, M.J., 1996. Shape From Shading. ing on the calibrated and normalized Clementine dome reveal a 750 nm reflectance of R750 = of lavas of intermediate to high viscosity and low http://www.newfrontiersinscience.com/martianenig- UVVIS reflectance data as provided by Eliason et al. 0.07806, a low value of the UV/VIS colour ratio of TiO2 content, erupting at an intermediate effusion mas/Articles/SFS/sfs.html (1999). The extracted Clementine UVVIS data were R415/R750 = 0.56338, indicating a low TiO2 con- rate. If the effusion of such lava continues over a examined in terms of 750 nm reflectance (albedo) tent, and a weak mafic absorption with R950/R750 long period of time, a steep flank slope and high [2] Charette, M. P., McCord, T. B., Pieters, C. M., and the R415/R750 and R950/R750 colour ratios. = 1.07864, suggesting a high soil maturity. The rhe- edifice volume may occur as in the case of Archytas Adams, J. B., 1974. Application of remote spectral Page 6 Selenology Vol. 28 No.3 Fall 2009 Page 7

reflectance measurements to lunar geology classifi- [10] Lena, R., Wöhler, C., 2008. Consolidated cation and determination of titanium content of lunar Lunar Dome Catalogue (CLDC). http://digilander. soils. J. Geophys. Res. 79, 1605-1613. libero.it/glrgroup/consolidatedlunardomecatalogue. The Photography htm [3] Eliason, E., Isbell, C., Lee, E., Becker, T., of Richard Hill Gaddis, L., McEwen, A., Robinson, M., 1999. [11] Lucey, P. G., Blewett, D. T., Hawke, B. R., Mission to the Moon: the Clementine UVVIS global 1998. Mapping the FeO and TiO2 content of the mosaic. PDS Volumes USA NASA PDS CL 4001 lunar surface with multispectral imagery, J. Geophys. 4078. http://pdsmaps.wr.usgs.gov Res., vol. 103, no. E2, pp. 3679-3699.

[4] Gillis, J. J., Lucey, P. G., 2005. Evidence that [12] Mosher, J., Bondo, H., 2006. Lunar UVVIS ratio is not a simple linear function of TiO2 Termination Visualization Tool (LTVT). http://inet. content for lunar mare basalts. Lunar Planet. Sci. uni2.dk/ d120588/henrik/jim ltvt.html XXXVI, abstract #2252. [13] Rubin, A. S., 1993. Dikes vs. diapirs in vis- [5] Head, J., Gifford, A., Lunar mare domes: coelastic rock. Earth and Planet. Sci. Lett. 199, pp. classification and modes of origin, The Moon and 641-659. Planets, 22, 1980. [14] Wilhelms, D., The Geologic History of the [6] Horn, B. K. P., 1989. Height and Gradient Moon, USGS Prof. Paper 1348. Washington: GPO, from Shading, MIT technical report, AI memo 1987. no. 1105A. http://people.csail.mit.edu/people/bkph/ AIM/AIM-1105A-TEX.pdf [15] Wilson, L., Head, J. W., 2003. Lunar Gruithuisen and Mairan domes: Rheology and mode [7] Lena, R., Wöhler, C., Bregante, M. T., of emplacement, J. Geophys. Res. 108(E2), pp. Fattinnanzi, C., 2006. A combined morphomet- 5012-5018. ric and spectrophotometric study of the complex lunar volcanic region in the south of Petavius. [16] Wöhler, C., Lena, R., Lazzarotti, P., Phillips, Journal of the Royal Astronomical Society of Canada J., Wirths, M., Pujic, Z., 2006. A combined spec- 100(1), pp. 14-25. trophotometric and morphometric study of the lunar mare dome fields near Cauchy, Arago, Hortensius, [8] Lena, R., Wöhler, C., Phillips, J., Wirths, and Milichius. Icarus 183(2), pp. 237-264. M., Bregante, M.T. 2007. Lunar domes in the Doppelmayer region: Spectrophotometry, [17] Wöhler, C., Lena, R., Phillips, J. Formation morphometry, rheology, and eruption conditions. of lunar mare domes along crustal fractures: Planetary and Space Science, vol. 55, 1201-1217. Rheologic conditions, dimensions of feeder dikes, and the role of magma evolution. [9] Lena, R., Wöhler, C., Bregante, M.T, Icarus, vol. 189, no. 2, pp. 279-307, 2007. Lazzarotti, P., Lammel, S., 2008. Lunar domes in Mare Undarum: Spectral and morphometric properties, eruption conditions, and mode of [18] Wöhler, C., Lena, R., 2009. Lunar intrusive emplacement. Planetary and Space Science, vol. 56, domes: Morphometric analysis and laccolith model- 3-4, pp. 553-569. ling. Icarus, in press. Page 8 Selenology Vol. 28 No.3 Fall 2009 Page 9 Page 10 Selenology Vol. 28 No.3 Fall 2009 Page 11 FROM THE PAPERS… Figure 2: Rectified 5a By Eric Douglass at angles of less than 10 degrees (with respect to the lunar surface), In this quarterly column, we will explore recent The Far Side of the Moon: A Photographic Guide). they tend to produce elliptical papers from the Lunar and Planetary Conferences. In his present study, the author examines eleva- craters. This effect doesn’t appear Our focus in on presenting topics of interest to the tion data for the presence of lunar basins. He to occur at the level of basins. broader lunar community. The summaries presented begins with the Clementine digital elevation maps Further, larger impacts are less here contain not only the results of the paper, but (DEMs), in order to refine our knowledge of lunar affected by local changes (as a also background information that connects the basins. This data holds out the promise, to those percent of variance) such as land- results to broader lunar topics and background of us who do visual astronomy, of new objects for slides, secondary impacts, ejecta information. which to search! from nearby impacts, and the like. Byrne’s method involves examining elevation After validating this methodology Paper: C. J. Byrne; “Radial Profiles of Lunar data for craters/basins larger than 200 km in diam- by comparing elevation data and Basins and Large Craters;” Lunar and Planetary eter. Using larger impacts allows Byrne to assume crater-centering data with known Science Conference XL; 3/2009; Poster Session II, that the shapes involved are circular in geometry visual examples, Byrne was ready Abstract 1351. which allows him to search for radial profiles to examine the basin data that is that conform to known crater/basin profiles. This usually accepted and to look for Most of us know this author, Charles Byrne, assumption doesn’t hold for smaller craters, which visually unknown basins. for his atlases of the moon (Lunar Orbiter occasionally manifest non-circular shapes. For Byrne came up with some sur- Photographic Atlas of the Near Side of the Moon; example, when small meteorites strike the moon prises. For example, his data sug- gested that the Grimaldi Basin is not a basin at all! Rather it is a 210 km (in diameter) crater with surrounding debris and rem- nants from other craters, creat- ing what only appears to be a basin ring at 430 km. In another example, his data suggested that Procellarum and Flamsteed- Billy, which were sometimes suspected of being basins, are not. However, the truly interesting conclusions are Figure 3: Rectified 5b Figure 1: Orthographic E2a Page 12 Selenology Vol. 28 No.3 Fall 2009 Page 13

Figure 5: Consolidated Lunar Atlas B18 Figure 4: Consolidated Lunar Atlas B19 Atlas, so that you can see the area without the Figure 2: Rectified 5a the possible new basins suggested by his data. This For each of these examples, I’ve provided five distortions of curvature. Figures 4 and 5 are from Figure 3: Rectified 5b provides observers with some new objects to iden- figures. Figure 1 is from the Orthographic Atlas the Consolidated Lunar Atlas, so that you can see Figure 4, 5: Consolidated Lunar Atlas B19, B18 tify! Indeed, if these are actual basins, then some of the Moon, and here you may locate the exact the areas in the usual visual projection, and from (2) Sinus Asperitatis East; lat 5; long 26.8; diameter visual remnants, at appropriate sun angles, may coordinates of the basin’s center, using the usual opposite sun angles. In each of these latter images, 560 km. yet be visible. For all lunar observers, this presents visual projection of the moon. Figure 2 is from a black circle marks the approximate center of the Figure 6: Orthographic B5e a unique opportunity to engage in lunar research. the Rectified Lunar Atlas, where the photographic basin, and sufficient area has been included so you Figure 7: Rectified 19a Below, I’ve selected two of these possible basins technique has eliminated the visual effects of the can plot out the rings. Figure 8: Rectified 19b from different areas of the moon, so that you can moon’s curvature, so that you can locate and plot (1) Basin Lavoissier-Mairan; lat. 40, long. -59.6; Figure 9, 10: Consolidated Lunar Atlas E9, E8 look for these throughout the lunar cycle. the rings. Figure 3 is also from the Rectified Lunar diameter 840 km. As we begin to look for these basins, what tale- Figure 1: Orthographic E2a tale signs might they have left? Basins of this size Page 14 Selenology Vol. 28 No.3 Fall 2009 Page 15

Figure 6: Orthographic B5e Figure 7: Rectified 19a

Figure 9: Consolidated Lunar Atlas E9 always have multiple rings. The diameter noted is kinds of clues to locate the rings. These are as assumed to be for the outer ring. Inner rings tend, follows: (1) a set of fragmented, subdued fea- for reasons unknown, to be spaced at a distance tures that may be connected into a ring. Indeed, approximating the square root of 2 apart. Thus, to look for rounded features with positive relief that find the approximate placement of an inner ring, don’t appear to be connected to the surrounding divide the diameter by 1.414. Unfortunately, the craters. (2) A set of features emerging through a rings aren’t generally visible, due either to degra- magma surface (one of the lunar ‘seas’), that may dation (meteorite erosion) or being covered over be connected into a ring. For example, sections of Figure 8: Rectified 19b (magma). Thus, you will have to rely on other one of the inner rings of the Imbrium Basin may Page 16 Selenology Vol. 28 No.3 Fall 2009 Page 17

Calling all authors, artists, and photographers! Participate in the discussion. Share your work. Selenology publishes drawings and photographs of the moon, articles about the moon or lunar observation, and poetry. Even if you only have a half- formed proposal for an article, drop us a line. We'll work with you. Send emails to: steveboint@ earthlink.net. Regular mail should be sent to: Selenology 1807 S. Spring Ave. Sioux Falls, SD 57105.

ALS MEMBERSHIP

Joining the American Lunar Society is simple. Our only requirement is that you are interested in lunar observation or studies. Once a member, you will receive our quarterly journal, Selenology. To become a member, mail a letter to the Figure 10: Consolidated Lunar Atlas E8 address below with a check for $15 US (all countries). be identified in this way (Mons Pico—Montes less than at the sides of the ring, and this differen- Please make check payable Teneriffe—Montes Recti—Mons Piton). These are, tial force produces a mare ridge above the ring. An to: American Lunar Society. simply put, the highest points of an inner ring and example of this effect is seen in Mare Serenitatis Please include both your therefore were not covered by the flooding magma. and marks one of that basin’s covered rings. (4) A e-mail and snail-mail (3) Mare ridges (wrinkle ridges) that have a radial combination of these features which may be joined addresses. or circular appearance. Magma is denser than the up into a ring-like structure. An example of this Andrew Martin, SFO crustal rock so that where it occurs in depth, it occurs in the Imbrium basin where some of the 722 Mapleton Rd, compresses the crustal rock. This means that where mare ridges are associated with isolated mountain Rockville, MD 20850 the magma is shallow, as above a basin’s interior fragments (figure 11). Figure 11: Imbrium basin mare ridges associated ring of mountains, it compresses the crustal rock As always, happy hunting. with isolated mountain fragments