Scaling impact melting and crater dimensions: Implications for the lunar cratering record

~~~ ~ Abstract-The dimensions of large craters formed by impact are controlled to a large extent by gravity, whereas the volume of impact melt created during the same event is essentially independent of gravity. This "differential scaling" fosters size-dependent changes in the dynamics of impact-crater and basin formation as well as in the final morphologies of the resulting structures. A variety of such effects can be observed in the lunar cratering record, and some predictions can be made on the basis of calculations of impact melting and crater dimensions. Among them are the following: (1) as event magnitude increases, the volume of melt created relative to that of the crater will grow, and more will be retained inside the rim of the crater or basin. (2) The depth of melting will exceed the depth of excavation at diameters that essentially coincide with both the inflection in the depth-diameter trend and the simple-to-complex transition. (3) The volume of melt will exceed that of the transient cavity at a cavity diameter on the order of the diameter of the Moon; this would arguably correspond to a Moon-melting event. (4) Small lunar craters only rarely display exterior flows of impact melt because the relatively small volumes of melt created can become choked with clasts, increasing the melt's viscosity and chilling it rapidly. Larger craters and basins should suffer little from such a process. (5) Deep melting near the projectile's axis of penetration during larger events will yield a progression in cen- tral-structure morphology; with growing event magnitude, this sequence should range from single peaks through multiple peaks to peak rings. (6) The minimum depth of origin of central-peak material should co- incide with the maximum depth of melting; the main central peak in a crater the size of Tycho should have had a preimpact depth of close to 15 km.

[1]  B. Siegal,et al.  Geometric interpretation of the ratio of overall diameter to rim crest diameter for lunar and terrestrial craters , 1973 .

[2]  James W. Head,et al.  Impact melt on lunar crater rims. , 1977 .

[3]  T. Ahrens,et al.  Impact-induced energy partitioning, melting, and vaporization on terrestrial planets , 1977 .

[4]  V. Oberbeck,et al.  Estimated thickness of a fragmental surface layer of Oceanus Procellarum. , 1967 .

[5]  Lauri J. Pesonen,et al.  The terrestrial impact cratering record , 1992 .

[6]  M. Cintala,et al.  Characteristics of the cratering process on small satellites and asteroids , 1978 .

[7]  Eugene M. Shoemaker,et al.  Impact mechanics at Meteor Crater, Arizona , 1959 .

[8]  J. Head,et al.  The Role of Rim Slumping in the Modification of Lunar Impact Craters , 1979 .

[9]  Keith A. Howard,et al.  Flows of impact melt at lunar craters , 1975 .

[10]  R. Grieve,et al.  Constraints on the formation of ring impact structures, based on terrestrial data , 1981 .

[11]  K. Holsapple,et al.  On the scaling of crater dimensions: 1. Explosive processes , 1980 .

[12]  J. Garvin,et al.  Test of a geometric model for the modification stage of simple impact crater development , 1989 .

[13]  T. Ahrens,et al.  Planetary cratering mechanics , 1993 .

[14]  R. Grieve.  Cratering in the lunar highlands - Some problems with the process, record and effects , 1980 .

[15]  Keith A. Howard,et al.  Fresh lunar impact craters: review of variations with size. , 1974 .

[16]  D. Ming.  Lunar sourcebook. A user's guide to the moon , 1992 .

[17]  H. Melosh,et al.  Core formation by giant impacts , 1991 .

[18]  S. Croft.  Scaling of Complex Craters , 1985 .

[19]  M. Cintala,et al.  The nature and effects of impact cratering on small bodies , 1979 .

[20]  Kevin R. Housen,et al.  Some recent advances in the scaling of impact and explosion cratering , 1987 .

[21]  Albert J. Chabai,et al.  On scaling dimensions of craters produced by buried explosives , 1965 .

[22]  S. Croft.  Energies of formation for ejecta blankets of giant impacts , 1977 .

[23]  T. Ahrens.  SHOCK MELTING AND VAPORIZATION OF METALS. , 1972 .

[24]  J. Head,et al.  Central peaks in lunar craters - Morphology and morphometry , 1979 .

[25]  Thomas J. Ahrens,et al.  Shock melting and vaporization of lunar rocks and minerals , 1972 .

[26]  R. M. Schmidt,et al.  Meteor Crater: Energy of formation - Implications of centrifuge scaling , 1980 .

[27]  R. Grieve,et al.  The Sudbury Structure' Controversial or Misunderstood? , 1991 .

[28]  J. H. Mackin.  Origin of Lunar Maria , 1969 .

[29]  R. Grieve,et al.  Volumetric analysis of complex lunar craters: Implications for basin ring formation , 1982 .

[30]  P. Claeys,et al.  Mega-impact melt petrology (Chicxulub, Sudbury, and the Moon): Effects of scale and other factors on potential for fractional crystallization and development of cumulates , 1996 .

[31]  Richard J. Pike,et al.  Geomorphology of impact craters on Mercury , 1988 .

[32]  T. Ahrens,et al.  Oblique Impact: A Process for Obtaining Meteorite Samples from Other Planets , 1986, Science.

[33]  P. Spudis,et al.  Apollo 17 impact melts and their relation to the Serenitatis basin , 1981 .

[34]  J. Head.  The significance of substrate characteristics in determining morphology and morphometry of lunar craters , 1976 .

[35]  F. Hörz,et al.  Bunte Breccia of the Ries: Continuous deposits of large impact craters , 1983 .

[36]  S. P. Marsh,et al.  Hugoniot equation of state of twelve rocks , 1967 .

[37]  E. I. Smith,et al.  Fresh lunar craters - Morphology as a function of diameter, a possible criterion for crater origin , 1973 .

[38]  B. French,et al.  Shock metamorphism of natural materials. , 1966, Science.

[39]  J. Garvin,et al.  A geometric model for excavation and modification at terrestrial simple impact craters , 1984 .

[40]  Mercurian crater rim heights and some interplanetary comparisons , 1979 .

[41]  M. Cintala,et al.  The effects of target characteristics on fresh crater morphology - Preliminary results for the moon and Mercury , 1977 .

[42]  K. Holsapple,et al.  Point source solutions and coupling parameters in cratering mechanics , 1987 .

[43]  H. Melosh,et al.  Magma ocean formation due to giant impacts , 1993 .

[44]  Elisabetta Pierazzo,et al.  A Reevaluation of Impact Melt Production , 1997 .

[45]  K. A. Holsapple,et al.  On the Scaling of Crater Dimensions 2. Impact Processes , 1982 .

[46]  Calculational investigation of impact cratering dynamics: material motions during the crater growth period. , 1980 .

[47]  R. Phillips,et al.  Impact cratering on Venus: Physical and mechanical models , 1991 .

[48]  D. H. Scott,et al.  Multiringed basins - Illustrated by Orientale and associated features. [geologic mapping and photographs of lunar ejecta] , 1974 .

[49]  R. Grieve.  The Haughton Impact Structure: Summary and Synthesis of the Results of the HISS Project* , 1988 .

[50]  S. Kieffer,et al.  The role of volatiles and lithology in the impact cratering process. , 1980 .

[51]  G. E. Duvall.  Pressure-Volume Relations in Solids , 1958 .

[52]  S. Croft.  The excavation stage of basin formation - A qualitative model , 1981 .

[53]  G. J. Taylor,et al.  Apollo 16 - Impact melt sheets, contrasting nature of the Cayley plains and Descartes mountains, and geologic history , 1984 .

[54]  R. J. Floran,et al.  Petrogenesis of melt rocks, Manicouagan Impact Structure, Quebec , 1978 .

[55]  A. Ruoff,et al.  Linear Shock‐Velocity‐Particle‐Velocity Relationship , 1967 .

[56]  S. Croft.  The Modification Stage of Basin Formation: Conditions of Ring Formation , 1981 .

[57]  Mark J. Cintala,et al.  Impact‐induced thermal effects in the lunar and Mercurian regoliths , 1992 .

[58]  P. Spudis.  Composition and origin of the Apennine Bench Formation , 1978 .

[59]  A. Chabai.  Influence of Gravitational Fields and Atmospheric Pressures on Scaling of Explosion Craters , 1976 .

[60]  G. J. Taylor,et al.  The complex stratigraphy of the highland crust in the Serenitatis region of the Moon inferred from mineral fragment chemistry , 1997 .

[61]  R. Grieve,et al.  The terrestrial cratering record: I. Current status of observations , 1979 .

[62]  D. Stöffler,et al.  The Allochthonous Polymict Breccia Layer of the Haughton Impact Crater, Devon Island, Canada , 1988 .

[63]  S. K. Croft,et al.  A proposed origin for palimpsests and anomalous pit craters on Ganymede and Callisto , 1983 .

[64]  David S. McKay,et al.  Origin of small lunar particles and breccia from the Apollo 11 site , 1970 .

[65]  J. Warner,et al.  Thermal model for impact breccia lithification: Manicouagan and the moon. , 1976 .

[66]  David E. Smith,et al.  The Shape and Internal Structure of the Moon from the Clementine Mission , 1994, Science.

[67]  J. McCauley,et al.  Orientale and Caloris , 1977 .

[68]  J. Warner,et al.  Thermal regimes in cratered terrain with emphasis on the role of impact melt , 1976 .

[69]  S. K. Croft,et al.  Cratering flow fields - Implications for the excavation and transient expansion stages of crater formation , 1980 .

[70]  P. Spudis,et al.  Composition of orientale basin deposits and implications for the lunar basin‐forming process , 1984 .

[71]  H. Melosh.  Impact Cratering: A Geologic Process , 1986 .

[72]  R. Grieve,et al.  The terrestrial cratering record: II. The crater production rate , 1979 .

[73]  P. Schultz,et al.  Impact melt generation and transport , 1980 .

[74]  David W. Hughes,et al.  Books-Received - the Geology of Multi-Ring Impact Basins - the Moon and Other Planets , 1993 .

[75]  S. Runcorn.  Book Review: Impact and Explosion Cratering. Proceedings of the Symposium on Planetary Cratering Mechanics. Pergamon Press, 1977, 1299 pp., US $150.00, £98.00, ISBN 0-08-022050-9 , 1984 .

[76]  M. Cintala,et al.  An analysis of differential impact melt‐crater scaling and implications for the terrestrial impact record , 1992 .

[77]  T. Ahrens,et al.  Impact-induced melting of planetary surfaces , 1992 .

[78]  Richard J. Pike,et al.  Depth/diameter relations of fresh lunar craters: Revision from spacecraft data , 1974 .

[79]  P. Moore.  Origin of the Lunar Maria , 1966, Nature.

[80]  M. Cintala,et al.  A method for estimating the initial impact conditions of terrestrial cratering events, exemplified by its application to Brent crater, Ontario , 1982 .

[81]  Verne R. Oberbeck,et al.  Thickness determinations of the lunar surface layer from lunar impact craters. , 1968 .

[82]  W. Hartmann,et al.  Moon: Origin and evolution of multi-ring basins , 1971 .

[83]  R. J. Floran,et al.  Manicouagan Impact Melt, Quebec 2. Chemical interrelations with basement and formational processes , 1978 .

[84]  R. Grieve,et al.  Cratering processes: as interpreted from the occurrence of impact melts. , 1977 .

[85]  J. Head.  Orientale multi-ringed basin interior and implications for the petrogenesis of lunar highland samples , 1974 .

[86]  M. Avermann,et al.  The formation of the Sudbury Structure, Canada: Toward a unified impact model , 1992 .

[87]  R. J. Floran,et al.  Manicouagan Impact Melt, Quebec, 1, Stratigraphy, petrology, and chemistry , 1978 .

[88]  D. E. Maxwell,et al.  Simple Z model for cratering, ejection, and the overturned flap. , 1976 .

[89]  The effects of differential scaling of impact melt and crater dimensions on lunar and terrestrial craters: Some brief examples , 1992 .

[90]  J. Head.  Stratigraphy of the descartes region (Apollo 16): implications for the origin of samples , 1974 .

[91]  D. Kring.  COMPOSITION OF EARTH’S CONTINENTAL CRUST AS INFERRED FROM THE COMPOSITIONS OF IMPACT MELT SHEETS , 1997 .