Geology topics

Jean-Pierre Williams

Publications and source records attributed to Jean-Pierre Williams.

6 recordsLinked to original sources

USGS2026

Lunar-VISE landing site selection and characterization at Mons Gruithuisen Gamma

The Lunar Vulkan Imaging and Spectroscopy Explorer (Lunar-VISE) was selected for a Commercial Lunar Payload Services (CLPS) delivery to the Gruithuisen domes region of the Moon as part of NASA’s Payloads and Research Investigation on the Surface of the Moon (PRISM) program. The Gruithuisen domes are chemically and morphologically distinct from their surroundings with a thorium-rich, silicic composition. The Lunar-VISE instrument payload is designed to investigate the compositional and thermophysical properties of dome materials in order to understand how late-stage silicic volcanism occurred on the Moon. Selection of a landing site required balancing science and exploration goals with the safety requirements for landing and rover trafficability. Science required access to boulders, potential exposures of bedrock, and if possible, rover access to the dome edge to enable observations of the surrounding maria. Safety considerations included landing hazards, maintenance of line-of-sight communications between the lander and rover, and any early morning or late afternoon shadows that would limit the mission duration. After consideration of several candidate landing sites, a 100-meter diameter landing ellipse centered on 36.45715° N, 319.20398° E, was selected near the edge of a topographic step and blocky ejecta crater (recently named Mareta) near the summit of Mons Gruithuisen Gamma. This location enables access to a field of boulders excavated by a relatively fresh impact providing a diversity of boulders for investigations, as well as views to the surrounding mare and Mons Gruithuisen Delta dome off of the dome edge via only a short rover traverse outside the landing ellipse (traverse < 100 m) while meeting safety requirements in accord with the CLPS risk posture.

Planetary Science Journal↗

USGS2026

Morphometric properties of the CP-21 landing site on the Moon at Mons Gruithuisen Gamma

Characterizing terrain surface properties is an essential step in assessing the feasibility of landing successfully at a location on a planetary surface. Slopes and terrain ruggedness index (TRI) values derived from high-resolution (2 m pixel −1 ) digital terrain models provided important constraints in selecting the landing site for the upcoming Payloads and Research Investigations on the Surface of the Moon program as part of the Commercial Lunar Payload Services task order CP-21 mission. The selected landing site needed to balance safety requirements with the ability to achieve the science and exploration goals of the Lunar Vulkan Imaging and Spectroscopy Explorer payload. In this study, we compare several morphometric parameters in the context of the CP-21 landing site on Mons Gruithuisen Gamma, or the Gamma dome, and quantify the information they convey about lunar surface properties to assess their utility for future landing site evaluation. TRI was found to be a useful metric for assessing landing site safety. Metrics that better decouple slope and surface roughness, the vector ruggedness measure and the standard deviation of slope, provided additional information about surface characteristics and textures such as the degree to which roughness is isotropic.

Planetary Science Journal↗

USGS2025

The pre-maria geologic history of the Imbrium basin preserved by remnant highlands massifs

The Imbrium basin is one of the largest and youngest impact basins on the Moon. It has experienced multiple phases of volcanism that filled the basin with basaltic lavas, obscuring most evidence of geologic activity prior to the emplacement of mare basalts. Elevated basin ring massifs, however, can retain some of that history due to their higher topographic elevation compared to the maria. In this work, we use thermal infrared and radar data sets in conjunction with compositional data sets to establish the presence of external material that has been deposited on top of several remnant basin massifs of Imbrium. These massifs originally formed as part of the Imbrium basin ring structure, but their material properties indicate that they have since experienced modification from outside sources. In southwest Imbrium, we present evidence that Mons Vinogradov was mantled by rock-poor, glassy pyroclastic material prior to the deposition of Eratosthenian-era basalts immediately surrounding the mons. In northern Imbrium, we find that Montes Recti and Montes Teneriffe were not affected by pyroclastic volcanism but rather were mantled by rock- and glass-poor ejecta materials likely related to the Iridum basin impact. At Mons Piton in eastern Imbrium, we see weaker glass signatures than those found at Mons Vinogradov, which we suggest could be due to a thin layer of reworked or partially buried glassy pyroclastic material. These results indicate that basin ring massifs provide a mechanism for studying the geologic history of lunar impact basins.

JGR Planets↗

USGS2023

The lunar cratering chronology

This chapter provides an introduction to crater-size frequency distribution (CSFD) measurements and presents a review of the work performed on dating lunar geological units using CSFDs since the last New Views of the Moon volume (2006), including various volcanic and tectonic features, as well as individual impact craters. At the end of the chapter, implications for the new CSFD age determinations for the geologic history and evolution of the Moon are discussed.

Reviews in Mineralogy and Geochemistry↗

USGS2022

Temperatures of the Lacus Mortis region of the Moon

Over 11 years of data acquired by the Diviner Lunar Radiometer Experiment instrument aboard Lunar Reconnaissance Orbiter have been compiled into a comprehensive data set of surface temperatures in the Lacus Mortis region which includes the landing ellipse of the Astrobotic Mission One lander mission. These data provide diurnal brightness temperatures at 128 pixels per degree (ppd) spatial resolution and 0.1 hr of local time resolution. From this data set, we highlight several features that display variations in radiative and thermophysical properties in the Lacus Mortis region and characterize the temperatures of the Astrobotic Mission One landing ellipse. We identify distinctly contrasting properties of materials in the walls of Bürg crater, hummocks of materials on the southeast margin of the mare basalts, and materials exposed or excavated by impacts. Additionally, we describe an exceptionally rocky fault scarp that predates the formation of Bürg crater suggesting the observed boulders are replenished on a timescale <1 Ga. Within the Astrobotic landing ellipse, temperatures are observed to range from ∼88 to ∼359 K with sunrise and sunset local times constrained to 5.8–6.3 hr and 17.8 and 18.1 hr respectively.

Earth and Space Science↗

USGS2011

The Mairan domes: silicic volcanic constructs on the Moon

The Mairan domes are four features located in northern Oceanus Procellarum at ∼312.3E, 41.4N on the Moon. High resolution visible imagery, visible-to-mid-IR spectra, and Lunar Prospector Th abundance data all indicate that these four domes have a composition that is consistent with derivation from a Si-rich, highly evolved magma.

Geophysical Research Letters↗