Geology of 243 Ida

R. Sullivan, R. Greeley, R. Pappalardo, E. Asphaug, J. M. Moore, D. Morrison, M. J S Belton, M. Carr, C. R. Chapman, P. Geissler, R. Greenberg, James Granahan, J. W. Head, R. Kirk, A. McEwen, P. Lee, P. C. Thomas, J. Veverka

Research output: Contribution to journalArticle

108 Citations (Scopus)

Abstract

The surface of 243 Ida is dominated by the effects of impacts. No complex crater morphologies are observed. A complete range of crater degradation states is present, which also reveals optical maturation of the surface (darkening and reddening of materials with increasing exposure age). Regions of bright material associated with the freshest craters might be ballistically emplaced deposits or the result of seismic disturbance of loosely-bound surface materials. Diameter/depth ratios for fresh craters on Ida are ∼1:6.5, similar to Gaspra results, but greater than the 1:5 ratios common on other rocky bodies. Contributing causes include rim degradation by whole-body "ringing," relatively thin ejecta blankets around crater rims, or an extended strength gradient in near-surface materials due to low gravitational self-packing. Grooves probably represent expressions in surface debris of reactivated fractures in the deeper interior. Isolated positive relief features as large as 150 m are probably ejecta blocks related to large impacts. Evidence for the presence of debris on the surface includes resolved ejecta blocks, mass-wasting scars, contrasts in color and albedo of fresh crater materials, and albedo streaks oriented down local slopes. Color data indicate relatively uniform calcium abundance in pyroxenes and constant pyroxene/olivine ratio. A large, relatively blue unit across the northern polar area is probably related to regolith processes involving ejecta from Azzurra rather than representing internal compositional heterogeneity. A small number of bluer, brighter craters are randomly distributed across the surface, unlike on Gaspra where these features are concentrated along ridges. This implies that debris on Ida is less mobile and/or consistently thicker than on Gaspra. Estimates of the average depth of mobile materials derived from chute depths (20-60 m), grooves (≥30 m), and shallowing of the largest degraded craters (20-50 m minimum, ∼100 m maximum) suggest a thickness of potentially mobile materials of ∼50 m, and a typical thickness for the debris layer of 50-100 m.

Original languageEnglish (US)
Pages (from-to)119-139
Number of pages21
JournalIcarus
Volume120
Issue number1
DOIs
StatePublished - Mar 1996
Externally publishedYes

Fingerprint

geology
craters
crater
ejecta
debris
albedo
rims
grooves
degradation
color
ringing
darkening
pyroxenes
scars
mass wasting
regolith
blankets
material
chutes
olivine

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Sullivan, R., Greeley, R., Pappalardo, R., Asphaug, E., Moore, J. M., Morrison, D., ... Veverka, J. (1996). Geology of 243 Ida. Icarus, 120(1), 119-139. https://doi.org/10.1006/icar.1996.0041

Geology of 243 Ida. / Sullivan, R.; Greeley, R.; Pappalardo, R.; Asphaug, E.; Moore, J. M.; Morrison, D.; Belton, M. J S; Carr, M.; Chapman, C. R.; Geissler, P.; Greenberg, R.; Granahan, James; Head, J. W.; Kirk, R.; McEwen, A.; Lee, P.; Thomas, P. C.; Veverka, J.

In: Icarus, Vol. 120, No. 1, 03.1996, p. 119-139.

Research output: Contribution to journalArticle

Sullivan, R, Greeley, R, Pappalardo, R, Asphaug, E, Moore, JM, Morrison, D, Belton, MJS, Carr, M, Chapman, CR, Geissler, P, Greenberg, R, Granahan, J, Head, JW, Kirk, R, McEwen, A, Lee, P, Thomas, PC & Veverka, J 1996, 'Geology of 243 Ida', Icarus, vol. 120, no. 1, pp. 119-139. https://doi.org/10.1006/icar.1996.0041
Sullivan R, Greeley R, Pappalardo R, Asphaug E, Moore JM, Morrison D et al. Geology of 243 Ida. Icarus. 1996 Mar;120(1):119-139. https://doi.org/10.1006/icar.1996.0041
Sullivan, R. ; Greeley, R. ; Pappalardo, R. ; Asphaug, E. ; Moore, J. M. ; Morrison, D. ; Belton, M. J S ; Carr, M. ; Chapman, C. R. ; Geissler, P. ; Greenberg, R. ; Granahan, James ; Head, J. W. ; Kirk, R. ; McEwen, A. ; Lee, P. ; Thomas, P. C. ; Veverka, J. / Geology of 243 Ida. In: Icarus. 1996 ; Vol. 120, No. 1. pp. 119-139.
@article{b8e523c9a75c43e9b5bb916a8233937e,
title = "Geology of 243 Ida",
abstract = "The surface of 243 Ida is dominated by the effects of impacts. No complex crater morphologies are observed. A complete range of crater degradation states is present, which also reveals optical maturation of the surface (darkening and reddening of materials with increasing exposure age). Regions of bright material associated with the freshest craters might be ballistically emplaced deposits or the result of seismic disturbance of loosely-bound surface materials. Diameter/depth ratios for fresh craters on Ida are ∼1:6.5, similar to Gaspra results, but greater than the 1:5 ratios common on other rocky bodies. Contributing causes include rim degradation by whole-body {"}ringing,{"} relatively thin ejecta blankets around crater rims, or an extended strength gradient in near-surface materials due to low gravitational self-packing. Grooves probably represent expressions in surface debris of reactivated fractures in the deeper interior. Isolated positive relief features as large as 150 m are probably ejecta blocks related to large impacts. Evidence for the presence of debris on the surface includes resolved ejecta blocks, mass-wasting scars, contrasts in color and albedo of fresh crater materials, and albedo streaks oriented down local slopes. Color data indicate relatively uniform calcium abundance in pyroxenes and constant pyroxene/olivine ratio. A large, relatively blue unit across the northern polar area is probably related to regolith processes involving ejecta from Azzurra rather than representing internal compositional heterogeneity. A small number of bluer, brighter craters are randomly distributed across the surface, unlike on Gaspra where these features are concentrated along ridges. This implies that debris on Ida is less mobile and/or consistently thicker than on Gaspra. Estimates of the average depth of mobile materials derived from chute depths (20-60 m), grooves (≥30 m), and shallowing of the largest degraded craters (20-50 m minimum, ∼100 m maximum) suggest a thickness of potentially mobile materials of ∼50 m, and a typical thickness for the debris layer of 50-100 m.",
author = "R. Sullivan and R. Greeley and R. Pappalardo and E. Asphaug and Moore, {J. M.} and D. Morrison and Belton, {M. J S} and M. Carr and Chapman, {C. R.} and P. Geissler and R. Greenberg and James Granahan and Head, {J. W.} and R. Kirk and A. McEwen and P. Lee and Thomas, {P. C.} and J. Veverka",
year = "1996",
month = "3",
doi = "10.1006/icar.1996.0041",
language = "English (US)",
volume = "120",
pages = "119--139",
journal = "Icarus",
issn = "0019-1035",
publisher = "Academic Press Inc.",
number = "1",

}

TY - JOUR

T1 - Geology of 243 Ida

AU - Sullivan, R.

AU - Greeley, R.

AU - Pappalardo, R.

AU - Asphaug, E.

AU - Moore, J. M.

AU - Morrison, D.

AU - Belton, M. J S

AU - Carr, M.

AU - Chapman, C. R.

AU - Geissler, P.

AU - Greenberg, R.

AU - Granahan, James

AU - Head, J. W.

AU - Kirk, R.

AU - McEwen, A.

AU - Lee, P.

AU - Thomas, P. C.

AU - Veverka, J.

PY - 1996/3

Y1 - 1996/3

N2 - The surface of 243 Ida is dominated by the effects of impacts. No complex crater morphologies are observed. A complete range of crater degradation states is present, which also reveals optical maturation of the surface (darkening and reddening of materials with increasing exposure age). Regions of bright material associated with the freshest craters might be ballistically emplaced deposits or the result of seismic disturbance of loosely-bound surface materials. Diameter/depth ratios for fresh craters on Ida are ∼1:6.5, similar to Gaspra results, but greater than the 1:5 ratios common on other rocky bodies. Contributing causes include rim degradation by whole-body "ringing," relatively thin ejecta blankets around crater rims, or an extended strength gradient in near-surface materials due to low gravitational self-packing. Grooves probably represent expressions in surface debris of reactivated fractures in the deeper interior. Isolated positive relief features as large as 150 m are probably ejecta blocks related to large impacts. Evidence for the presence of debris on the surface includes resolved ejecta blocks, mass-wasting scars, contrasts in color and albedo of fresh crater materials, and albedo streaks oriented down local slopes. Color data indicate relatively uniform calcium abundance in pyroxenes and constant pyroxene/olivine ratio. A large, relatively blue unit across the northern polar area is probably related to regolith processes involving ejecta from Azzurra rather than representing internal compositional heterogeneity. A small number of bluer, brighter craters are randomly distributed across the surface, unlike on Gaspra where these features are concentrated along ridges. This implies that debris on Ida is less mobile and/or consistently thicker than on Gaspra. Estimates of the average depth of mobile materials derived from chute depths (20-60 m), grooves (≥30 m), and shallowing of the largest degraded craters (20-50 m minimum, ∼100 m maximum) suggest a thickness of potentially mobile materials of ∼50 m, and a typical thickness for the debris layer of 50-100 m.

AB - The surface of 243 Ida is dominated by the effects of impacts. No complex crater morphologies are observed. A complete range of crater degradation states is present, which also reveals optical maturation of the surface (darkening and reddening of materials with increasing exposure age). Regions of bright material associated with the freshest craters might be ballistically emplaced deposits or the result of seismic disturbance of loosely-bound surface materials. Diameter/depth ratios for fresh craters on Ida are ∼1:6.5, similar to Gaspra results, but greater than the 1:5 ratios common on other rocky bodies. Contributing causes include rim degradation by whole-body "ringing," relatively thin ejecta blankets around crater rims, or an extended strength gradient in near-surface materials due to low gravitational self-packing. Grooves probably represent expressions in surface debris of reactivated fractures in the deeper interior. Isolated positive relief features as large as 150 m are probably ejecta blocks related to large impacts. Evidence for the presence of debris on the surface includes resolved ejecta blocks, mass-wasting scars, contrasts in color and albedo of fresh crater materials, and albedo streaks oriented down local slopes. Color data indicate relatively uniform calcium abundance in pyroxenes and constant pyroxene/olivine ratio. A large, relatively blue unit across the northern polar area is probably related to regolith processes involving ejecta from Azzurra rather than representing internal compositional heterogeneity. A small number of bluer, brighter craters are randomly distributed across the surface, unlike on Gaspra where these features are concentrated along ridges. This implies that debris on Ida is less mobile and/or consistently thicker than on Gaspra. Estimates of the average depth of mobile materials derived from chute depths (20-60 m), grooves (≥30 m), and shallowing of the largest degraded craters (20-50 m minimum, ∼100 m maximum) suggest a thickness of potentially mobile materials of ∼50 m, and a typical thickness for the debris layer of 50-100 m.

UR - http://www.scopus.com/inward/record.url?scp=16144366697&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=16144366697&partnerID=8YFLogxK

U2 - 10.1006/icar.1996.0041

DO - 10.1006/icar.1996.0041

M3 - Article

VL - 120

SP - 119

EP - 139

JO - Icarus

JF - Icarus

SN - 0019-1035

IS - 1

ER -