Clementine GLTM-2 altimetry and GLGM-2 gravity from Clementine and historical tracking provide free-air and Bouguer gravity maps at the lunar surface for wavelengths>200 km. A preliminary study found that lunar topography is not compensated by a single mechanism and maintains significant rigidity over 3 b.y. time scales. Interpretation of these data via flexural isostatic models constrains the flexural rigidity of the lithosphere lie in the range 4x10^23 to 10^25 N m for most nearside basins. These correspond to effective elastic thicknesses of 40 to 120 km. While the coherence method gives relatively robust estimates of lithospheric thickness, interpreting the Bouguer anomaly (BA) in this fashion requires some caution. The uncertainty in the gravity data increases dramatically at short wavelengths, and makes estimation of the relative proportion of subsurface to surface loadings difficult. In addition, most short-wavelength topography results from impact processes that violate the assumption that such loadings are statistically uncorrelated. Nevertheless, coherence analysis can provide a lower bound on lithospheric strength.
Lunar and Planetary Science Conference
- Pub Date:
- March 1996
- BASINS: LUNAR;
- CLEMENTINE: GEOPHYSICS;