Tsiolkovsky crater: A window into crustal processes on the lunar farside

Abstract

Abstract. Mineralogy and distribution of rock types in the Tsiolkovsky region of the lunar farside are evaluated in terms of crustal stratigraphy and evolution. Calibrated multispectral images from five orbits of Clementine data provide compositional information at a scale that allows diverse geologic features to be analyzed and compared. The entire region is seen to be highly anorthositic. with outcrops of relatively pure anorthosite quite common. The crater itself has excavated blocks of anorthosite and noritic anorthosite from the near-surface highland crust, often in a mixed jumble. The central peaks of Tsiolkovsky, which have exhumed much deeper material, however, are composed of relatively pure anorthosite with olivine-rich zones concentrated near the ridge crests. Boundaries between the anorthosite and olivine-rich zones are sharp, but spatial relations suggest the coherent olivine-rich zone is relatively thin (<1 km). The composition of the mare material filling Tsiolkovsky is shown to be low-titanium basalt. Smaller exposures of mare basalt occur about one crater radius from the rim. The crustal structure to -25 km in this region prior to the Tsiolkovsky impact appears to be (top to bottom) a few kilometers of anorthositic breccias comprising the megaregolith, a zone of crystalline anorthosite with pockets of noritic anorthosite, a zone of anorthosite devoid of iron-bearing minerals, and a zone of relatively pure anorthosite containing olivine-rich material, possibly emplaced as intrusions.

Chemical information content of lunar thermal and epithermal neutrons

“…We therefore conclude that the abundance of FeO in the lunar highlands is between 1.9 and 4.9%. This range contains the average FeO abundance derived from Clementine spectral reflectance data (FeO = 4.2% ] and <4.9% Pieters and Tompkins, 1999]) and from analyses of lunar meteorites (5.2% [Palme et al, 1991]). However, it is significantly less than that derived from Apollo gamma-ray data (FeO = 7.7% [Haines and Metzger, 1980;Davis, 1980]).…”

Major lunar crustal terranes: Surface expressions and crust‐mantle origins

“…Although local pockets of intercumulus mafic rocks containing heat-producing residua may reside within the FHT, they are probably not abundant. Where mafic rocks were exhumed by deep impacts, such as, for example Tsiolkovsky Pieters and Tompkins, 1999], their extent appears to be limited. In the case of SPA, the ensuing mantle uplift may have contributed to local, minor generation of melting and mare basalt production if the impact event occurred early enough that the underlying mantle was still hot or even partially molten.…”

The Compensation State of Intermediate Size Lunar Craters

“…This would have a similar effect to that of the cryptomare. Subsurface ponding has been proposed as a plausible process for some of the mare flows associated with crater Tsiolkovskiy, where both surface and subsurface ponding are expected to have occurred (Pieters and Tompkins 1999). However, in the present analysis Tsiolkovskiy falls in the irregular categorization (see below), most likely due to inadequate gravity coverage.…”