Characterization of previously unidentified lunar pyroclastic deposits using Lunar Reconnaissance Orbiter Camera data

Abstract

[1] We used a Lunar Reconnaissance Orbiter Camera (LROC) global monochrome Wide-angle Camera (WAC) mosaic to conduct a survey of the Moon to search for previously unidentified pyroclastic deposits. Promising locations were examined in detail using LROC multispectral WAC mosaics, high-resolution LROC Narrow Angle Camera (NAC) images, and Clementine multispectral (ultraviolet-visible or UVVIS) data. Out of 47 potential deposits chosen for closer examination, 12 were selected as probable newly identified pyroclastic deposits. Potential pyroclastic deposits were generally found in settings similar to previously identified deposits, including areas within or near mare deposits adjacent to highlands, within floor-fractured craters, and along fissures in mare deposits. However, a significant new finding is the discovery of localized pyroclastic deposits within floor-fractured craters Anderson E and F on the lunar farside, isolated from other known similar deposits. Our search confirms that most major regional and localized low-albedo pyroclastic deposits have been identified on the Moon down to $100 m/pix resolution, and that additional newly identified deposits are likely to be either isolated small deposits or additional portions of discontinuous, patchy deposits.

The Lassell massif—A silicic lunar volcano

“…The association of these low-reflectance deposits with some of the highest silica and lowest FeO concentrations in the study area is consistent with a silicic composition (i.e., a quenched flow surface). However, similar exposures of low-reflectance deposits are observed in regional dark mantle deposits (RDMDs) including Sulpicius Gallus, TaurusLittrow, and Aristarchus; and in many localized dark mantling deposits (LDMDs) (e.g., Gaddis et al, 1985Gaddis et al, , 20 0 0, 2011Gustafson et al, 2012;Hawke et al, 2013 ;Schmitt, personal communication, 2013). Not all of these deposits exhibit uniform spectral features.…”

Generation, ascent and eruption of magma on the Moon: New insights into source depths, magma supply, intrusions and effusive/explosive eruptions (Part 2: Predicted emplacement processes and observations)

“…1) Regional pyroclastic deposits: Regional dark mantle (pyroclastic) deposits have been mapped and characterized by a number of workers (Gaddis et al, 1985(Gaddis et al, , 1998(Gaddis et al, , 2000(Gaddis et al, , 2003Weitz et al, 1998;Gustafson et al, 2012) (Figure 26a). Weitz et al (1998) analyzed seven regional dark mantle deposits (DMDs) using Clementine five-channel UV-visible (UVVIS) data to determine their extent and stratigraphic relationship to other geologic units.…”

Micro‐FTIR Spectroscopy of Lunar Pyroclastic and Impact Glasses as a New Diagnostic Tool to Discern Them

“…These criteria are commonly combined to determine the origin of lunar glass fragments (e.g., Collareta et al ; Korotev et al ; Zeigler et al, ; Zeng et al, ). To date, more than 120 lunar pyroclastic deposits, also known as dark‐mantle deposits, have been recognized on the Moon based on remote sensing data such as the WAC image, titanium composition, and VNIR spectra (e.g., Gaddis et al, ; Gustafson et al, ). However, as volcanic and impact‐generated glasses have the same VNIR spectral properties (Jawin et al, ; Tompkins & Pieters, ), this may lead to misidentification of impact glass as volcanic glass (Jawin et al, ).…”