J. H. Pasckert

University of Münster | WWU · Institute of Planetology

The effect of surface regolith gardening and melt layer production produced by space weathering (SW) (owing to micrometeorite [according to comment rev#1] bombardment) of surficial regolith layers of airless planetary surfaces was investigated in an experimental setup by using laser-induced ablation of powdered analog material (synthetic Fo100) und...

In this study we investigated the previously observed young resurfacing absolute model ages at the floor of Occator crater on dwarf planet Ceres on the basis of Dawn data. These young resurfacing absolute model ages have been interpreted to represent the deposition of cryovolcanic material >10 Myr after the formation of Occator crater. In our study...

We present the results of our studies of the rheological properties and ages on Alba Mons lava flows. Previous studies have shown that the rheology of lava flows, such as yield strength and viscosity, as well as external parameters affecting flow characteristics, such as effusion rate and eruption duration can be derived by remotely sensed dimensio...

Like many airless planetary surfaces, the surface of the Moon is scattered by populations of blocks and smaller boulders. These features decrease in abundance with increasing exposure time due to comminution by impact bombardment and produce regolith. Here we model the evolution of block size–frequency distributions by updating the model of Hörz et...

Ceres is a partially differentiated dwarf planet, as confirmed by NASA’s Dawn mission. The Urvara basin (diameter ~170 km) is its third-largest impact feature, enabling insights into the cerean crust. Urvara’s geology and mineralogy suggest a potential brine layer at the crust-mantle transition. Here we report new findings that help in understandin...

Surficial regolith layers of atmosphere-free planetary surfaces are altered by a multitude of processes summarized as space weathering. Minerals comprising such altered surfaces can differ significantly (in terms of structure and resulting alteration products) from their terrestrial laboratory counterparts. These changes, when altered vs. unaltered...

The unmixing model used in this study has previ- ously been used for spectral unmixing of NASA RELAB data and lunar analog materials. In the framework of MERTIS it is applied to laborator mineral mixtures, including glasses and varying grain sizes [12-14]. These mixtures are prepared and analyzed at the IRIS (Infrared and Raman for Interplanetary S...

Like many airless planetary surfaces, the surface of the Moon is scattered by populations of blocks and smaller boulders. These features decrease in abundance with increasing exposure time due to comminution by impact bombardment and produce regolith. Here we model the evolution of block size-frequency distributions by updating the model of Hoerz e...

The lunar surface has been exposed to the space environment for billions of years and during this time has accumulated records of a wide range of astrophysical phenomena. These include solar wind particles and the cosmogenic products of solar particle events which preserve a record of the past evolution of the Sun, and cosmogenic nuclides produced...

The lunar surface has been exposed to the space environment for billions of years and during this time has accumulated records of a wide range of astrophysical phenomena. These include solar wind particles and the cosmogenic products of solar particle events which preserve a record of the past evolution of the Sun, and cosmogenic nuclides produced...

Before acquiring highest-resolution data of Ceres, questions remained about the emplacement mechanism and source of Occator crater’s bright faculae. Here we report that brine effusion emplaced the faculae in a brine-limited, impact-induced hydrothermal system. Impact-derived fracturing enabled brines to reach the surface. The central faculae, Cerea...

NASA’s Dawn mission revealed a partially differentiated Ceres that has experienced cryovolcanic activity throughout its history up to the recent past. The Occator impact crater, which formed ~22 Myr ago, displays bright deposits (faculae) across its floor whose origins are still under debate: two competing hypotheses involve eruption of brines from...

https://www.hou.usra.edu/meetings/lpsc2020/pdf/1951.pdf

This study deals with an aspect of blocks observed on many rocky planetary surfaces: in situ fragmentation. Using LROC/NAC images, we characterized the morphology, morphometry and abundance of in-situ fractured blocks observed on the rim of six large impact craters of known emplacement age on the Moon. The relative number of disrupted blocks increa...

Extensional and compressional structures are globally abundant on Mars. Distribution of these structures and their ages constrain the crustal stress state and tectonic evolution of the planet. Here in this paper, we report on our investigation over the distribution of the tectonic structures and timings of the associated stress fields from the Noac...

A 1:4M global geologic map of dwarf planet (1) Ceres was completed by the science team from NASAs Dawn mission, derived from images obtained during the Low Altitude Mapping Orbit (LAMO, 35 m/px). The map was published on the cover of Icarus, volume 316, December 2018 issue, along with a series of papers describing the geology within Ceres quadrangl...

A 1:4M global geologic map of dwarf planet (1) Ceres was completed by the science team from NASAs Dawn mission, derived from images obtained during the Low Altitude Mapping Orbit (LAMO, 35 m/px). The map was published on the cover of Icarus, volume 316, December 2018 issue, along with a series of papers describing the geology within Ceres quadrangl...

We conducted a detailed photogeological analysis of the northern portion of the South Pole-Aitken (SPA) basin (10–60°S, 125–175°W) and compiled a geological map (1:500,000 scale) of this region. Our new absolute model age for the Apollo basin, 3.98 + 0.04/−0.06 Ga, provides a lower age limit for the formation of the SPA basin. Some of the plains un...

The geologic context of red organic-rich materials (ROR) found across an elongated 200 km region on Ceres is evaluated with spectral information from the multispectral framing camera (FC) and the visible and near-infrared mapping spectrometer (VIR) of Dawn. Discrete areas of ROR materials are found to be associated with small fresh craters less tha...

Dawn is the first spacecraft to visit and orbit Ceres, the largest object in the asteroid belt and the only dwarf planet in the inner Solar System. The Dawn science team undertook a systematic geologic mapping campaign of Ceres' entire surface. Here we present our contribution to this mapping campaign, a geologic map and geologic history of the Ezi...

The Dawn Framing Camera repeatedly imaged Ceres' North Pole quadrangle (Ac-1 Asari, latitudes >66°N) at a resolution of ∼35m/pixel through a panchromatic filter, enabling the derivation of a digital terrain model (DTM) and an ortho-rectified mosaic. Using this dataset, a photo-geologic map and stratigraphy, complemented with absolute model ages of...

We identified and mapped 129 mare basalt deposits in and around the South Pole–Aitken (SPA) basin, and determined absolute model ages (AMAs) for 101 of these units by performing crater size-frequency distribution (CSFD) measurements. The derived AMAs range from 2.2 Ga to 3.7 Ga, with the youngest deposits within Antoniadi crater and the oldest depo...

Since its arrival at Ceres, Dawn's Framing Camera has been imaging the dwarf planet at different altitudes, using 8 different filters. Based on these images, global clear filter mosaics, digital terrain models, and global color mosaics were produced. These datasets are basis for the derived photo-geologic map of the Ac-2 Coniraya quadrangle, locate...

Five decades of observations of Ceres suggest that the dwarf planet has a composition similar to carbonaceous meteorites and may have an ice-rich outer shell protected by a silicate layer. NASA’s Dawn spacecraft has detected ubiquitous clays, carbonates and other products of aqueous alteration across the surface of Ceres, but surprisingly it has di...

The Global Geologic Map of Ceres Based on Dawn HAMO Observations

The HAMO-Based Global Geologic Map of Ceres

In the last decades, the exploration of planets and moons by spacecraft revealed a variety of volcanic expressions. The recent visit to dwarf planet Ceres by the Dawn spacecraft is shedding light on a possible new, compositionally different volcanism falling into the cryovolcanism field. The dwarf planet’s properties, i.e., low bulk density, low in...

INTRODUCTION Classic volcanism prevalent on terrestrial planets and volatile-poor protoplanets, such as asteroid Vesta, is based on silicate chemistry and is often expressed by volcanic edifices (unless erased by impact bombardment). In ice-rich bodies with sufficiently warm interiors, cryovolcanism involving liquid brines can occur. Smooth plains...

INTRODUCTION Thermochemical models have predicted that the dwarf planet Ceres has, to some extent, formed a mantle. Moreover, due to viscous relaxation, these models indicate that Ceres should have an icy crust with few or no impact craters. However, the Dawn spacecraft has shown that Ceres has elevation excursions of ~15 km, cliffs, graben, steep-...

Before NASA's Dawn mission, the dwarf planet Ceres was widely believed to contain a substantial ice-rich layer below its rocky surface. The existence of such a layer has significant implications for Ceres's formation, evolution, and astrobiological potential. Ceres is warmer than icy worlds in the outer Solar System and, if its shallow subsurface i...

The analysis of the impact crater size-frequency distribution (CSFD) is a well-established approach to the determination of the age of planetary surfaces. Classically, estimation of the CSFD is achieved by manual crater counting and size determination in spacecraft images, which, however, becomes very time-consuming for large surface areas and/or h...

The analysis of the impact crater size-frequency distribution (CSFD) is a well-established approach to the determination of the age of planetary surfaces. Classically, estimation of the CSFD is achieved by manual crater counting and size determination in spacecraft images, which, however, becomes very time-consuming for large surface areas and/or h...

Since the late 1970’s, the possibility of ice on Ceres has been a topic of broad discussion that engages data ranging from surface spectroscopy to shape and density. Thermal models suggest that subsurface ice on Ceres is stable for the lifetime of the solar system. Dawn arrived at Ceres in 2015 with a suite of instruments to answer this question bu...

Boguslawsky crater (72.9°S, 43.3°E, ~100 km in diameter) is a primary target for the Luna-Glob mission. The crater has a morphologically smooth (at the resolution of WAC images), flat, and horizontal floor, which is about 55–60 km in diameter. Two ellipses were selected as specific candidate landing areas on the floor: the western ellipse is center...

We identified and mapped 28 mare basalt occurrences, between the Australe and South Pole-Aitken basins on the southern lunar farside, and determined their absolute model ages (AMAs) by performing crater size-frequency distribution (CSFD) measurements. Our study area can be subdivided into seven major mare basalt occurrences in and around Bolyai, Ro...

This review summarizes the use of High Resolution Stereo Camera (HRSC) data as an instrumental tool and its application in the analysis of geological processes and landforms on Mars during the last ten years of operation. High-resolution digital elevations models on a local to regional scale are the unique strength of the HRSC instrument. The analy...

Radar provides a unique means to analyze the surface and subsurface physical properties of geologic deposits, including their wavelength-scale roughness, the relative depth of the deposits, and some limited compositional information. The NASA Lunar Reconnaissance Orbiter’s (LRO) Miniature Radio Frequency (Mini-RF) instrument has enabled these analy...

We investigated 28 volcanic mare deposits in and around Rosseland Crater at the southern lunar farside. We got absolute model ages of 1.7-3.8 Ga.

We mapped 103 mare deposits in and outside the South Pole-Aitken Basin and derived absolute model ages for 50 of those mare basalts.

We studied the floor of crater Boguslawsky (~95 km in diameter, centered at 72.9°S, 43.26°E), which was selected as the landing site for the Luna-Glob mission.

Morphometric analyses of wrinkle ridges on the eastern Hellas basin floor, Mars, indicate a ~2-km-thick basalt layer compressed by an isotropic stress field.

We have dated several small mare deposits around the lunar farside craters Pauli and Rosseland, by performing crater size-frequency distribution measurements.

We mapped and dated several small volcanic deposits in and around Rosseland and Bolyai crater, by performing crater size-frequency distribution measurements (CSFD). We found ages between 1.6 and 3.7 Ga with peaks around 2.0 Ga and 3.7 Ga.

Lunar Reconnaissance Orbiter Camera (LROC) images allow us to perform detailed crater size-frequency distribution (CSFD) measurements of the SPA basin to derive absolute model ages of the basin itself as well as several superposed impact structures. The SPA basin is of interest because (1) it might have penetrated the entire lunar crust and exposed...

We studied light plains in the north-eastern South-Pole Aitken basin to investigate their origin, ages, and mineralogical composition. Light plains, also known as the Cayley Formation, occur on the near- and farside of the Moon. Due to their smooth texture, lower crater densities, and occurrence as crater fills, they were thought to be of volcanic...

In this study we obtained crater size-frequency distribution measurements to derive absolute model ages of light plains in the South Pole Aitken basin. Furthermore we analyzed their mineralogical composition.

We performed new crater size-frequency distribution (CSFD) measurements for the South Pole-Aitken basin (SPA) and several superposed craters and basins. Our crater counts indicate an absolute model age of 4.26 Ga for SPA.

The accurate definition of the lunar cratering chronology is important for deriving absolute model ages across the lunar surface and throughout the Solar System. Images from the Lunar Reconnaissance Orbiter Narrow Angle Cameras and Wide-Angle Camera and the SELENE/Kaguya Terrain Camera provide new opportunities to investigate crater size-frequency...

We present results of our study of the rheologies and ages of lava flows on the Elysium Mons volcano, Mars.

We have performed new crater size-frequency distribution measurements for melt pools, the floor, and the ejecta blanket of Copernicus crater.

We have mapped 25 individual lava flows in the Elysium Mons region and measured their dimensions. On the basis of these measurements, we have calculated the yield strengths, effusion rates and viscosities of the lava flows.