Multi-ring basins are large impact craters formed in the early history of planets. They critically affect the evolution of the planets and their satellites. The Moon offers an exceptional chance to study these phenomena and this book provides a comprehensive geological study using data from lunar landings and remote sensing of the Moon. The author covers the formation and development of basins and considers their chemistry and mineralogy. He studies their effects on the volcanic, tectonic and geological evolution of the planet, including the catastrophic consequence on the planetary climate and evolution of life. This study is lavishly illustrated with many spectacular, highly-detailed photographs and diagrams.

More than 15 years of planetary exploration of Mars have given insight into the geologic processes that have shaped its surface. The newly acquired Viking data have shown that volcanism is one of the most important geologic processes operating on Mars throughout its history. In situ chemical analyses of Martian soil by the Viking lander spacecraft indicate mafic to ultramafic source rocks. This is consistent both with available remote sensing data, which indicate the presence of mafic minerals such as pyroxene and olivine, and with petrologic modeling, based on available geophysical data which suggest that Martian lavas are probably iron rich and ultramafic. These data strongly suggest that basaltic volcanism is widespread on Mars, and much of the photogeological data may be studied in this context. Photogeological analysis of the Martian surface has shown two main types of volcanic morphologies: the first type is central volcanoes, which are volcanic landforms developed by continued and prolonged eruption from a point source vent. This category includes (1) shields, the classic low‐profile volcanic mountains of which Olympus Mons is the most spectacular example, (2) domes, steep‐sided constructs, such as Tharsis Tholus, that may represent lower rates of eruption than the shields or, possibly, more silicic lava compositions, (3) highland patera, radially textured low‐profile volcanoes that occur in the cratered terrain and are interpreted as ash shields, (4) Alba Patera, an apparently unique volcanic landform consisting of a vast volcanic center over 1500 km across with flank slopes of less than a tenth of a degree, and (5) various small features such as cinder cones. The second major category is volcanic plains, which are units recognized by several criteria, of which the presence of mare ridges and flow lobes are the most useful. Volcanic plains are subdivided into four main groups: (1) simple flows, broad, smooth to rolling plains that contain numerous mare‐type ridges but no flow lobes, interpreted as being composed of thick, single‐cooling units, (2) complex flows, displaying multiple overlapping flow lobes interpreted to be indicative of thin, multiple‐cooling units, (3) undifierentiated flows, plains that typically lack any morphologic identifying feature but are considered to be volcanic partly on the basis of their association with large volcanic centers, and (4) questionable plains, volcanic(?) units heavily modified by other processes (erosion, tectonism, etc.) so that their origins are uncertain. When these categories of volcanic morphologies are combined with relative age data provided by crater statistics, a volcanic history for Mars can be derived as follows: Early heavy bombardment of Mars was accompanied and followed by small‐scale fluvial channeling, extensive flood volcanism (the plateau plains), and ash shield volcanism in the cratered terrain. Shortly after this time, less extensive flood volcanism continued to resurface the planet during formation of the northern/southern hemisphere dichotom...

S>fflk+.SmSt> i 0 0,\g gN l r g t^l,-^:,g. 'X @W0-';D4:* -W u iA 27. P. de Loriol, Paleontologie Fran,aise, ou Description des Fossiles de la France, Serie 1, Animaux Invertebr6s. Terrain Jurassique (Masson, Paris, 1882-1889. 28. Because of incomplete preservation, most species have at least some missing character data. In this analysis used the species in each genus with the fewest missing characters. 29. Because unordered characters cannot be averaged, first ordinated species using principal-coordinates analysis [J. C. Gower, Biometrika 53, 325 (1966)] on the between-species morphological distance matrix (10). Twenty principal coordinates were used because interspecies distances based on this number of coordinates correlate well with distances based on the raw character data. Similar results are obtained if other numbers of principal coordinates are used. 30. S. J. Gould and C. B. Calloway, Paleobiology 6, 383 (1980). 31. D. L. Meyer and D. B. Macurda Jr., ibid. 3, 74 (1977). 32. E. S. Pearson, Biometrika 18, 173 (1926); M. Foote, Paleobiology 18, 1 (1992). 33. M. Slatkin, Paleobiology 7, 421 (1981); J. W. Valentine et al., ibid. 20, 131 (1994). 34. N. G. Lane, J. Paleontol. 37, 917 (1963); J. C. Brower, ibid. 40, 613 (1966); ibid. 61, 999 (1987); A. Breimer, Proc. K. Ned. Akad. Wet. Ser. B 72, 139 (1969); and G. D. Webster, ibid. 78, 149 (1975); D. L. Meyer, Mar. Biol. 22, 105 (1973); in Echinoderm Nutrition, M. Jangoux and J. M. Lawrence, Eds. (Balkema, Rotterdam, 1983), pp. 25-42; M. Roux, Geobios (Lyon) 11, 213 (1978); A. Breimer and N. G. Lane, in Treatise on Invertebrate Paleontology, part T, Echinodermata 2, R. C. Moore and C. Teichert, Eds. (Geological Society of America, Boulder, CO, and University of Kansas, Lawrence, KS, 1978), pp. 316-347; G. Ubaghs, ibid., pp. 58-216; W. I. Ausich, J. Paleontol. 54, 273 (1980); ibid. 57, 31 (1983); ibid. 62, 906 (1988); C. E. Brett, Lethaia 14, 343 (1981); S. K. Donovan, ibid. 21, 169 (1988); ibid. 23, 291 (1990); T. W. Kammer, J. Paleontol. 59, 551 (1985); and W. I. Ausich, Paleobiology 13, 379 (1987 using laser illumination of a particle suspension (13,14). A high ratio of same sense to opposite sense polarization and high reflectivity has been detected by radar observations of the Galilean satellites of Jupiter (15,16,17) to observe from the Earth. Radar can identify deposits of frozen volatiles because, under certain conditions, they produce a unique radar signature (6). However, such radar observations may not be conclusive depending on the quantity of volatiles present, the nature of the surface, and the sensitivity of the measurements. Frozen volatiles have much lower transmission loss than silicate rocks, producing a higher average radar reflectivity than silicate rocks. Total internal reflection also preserves the transmitted circular polarization sense in the scattered signal. An opposition surge or coherent backscatter opposition effect (CBOE) (7-12) may also be observed as the phase, or bistatic angle 1 (Fig. 1), approaches 0. The CBOE requir...

In the course of 71 days in lunar orbit, from 19 February to 3 May 1994, the Clementine spacecraft acquired just under two million digital images of the moon at visible and infrared wavelengths. These data are enabling the global mapping of the rock types of the lunar crust and the first detailed investigation of the geology of the lunar polar regions and the lunar far side. In addition, laser-ranging measurements provided the first view of the global topographic figure of the moon. The topography of many ancient impact basins has been measured, and a global map of the thickness of the lunar crust has been derived from the topography and gravity.

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