Henrik I. Hargitai

Map Projections in Planetary Cartography

Reference surfaces, coordinate systems and projections are the prerequisites for the geospatial analysis of planetary surfaces. In the followings we discuss how these parameters are defined and used on different types of planetary bodies, including rocky planets, satellites, irregular bodies and gas giants.

Late Amazonian–Aged Channel and Island Systems Located East of Olympus Mons, Mars

Abstract We mapped the northwestern Tharsis region to the east of Olympus Mons and described three distinct channel-and-island morphologies within three channel groups. Islands include irregular and streamlined islands in both lava flows and fluvial systems and residual islands in collapsed systems. We interpret these channels to have formed by a combination of tectonic, collapse, lava, and fluvial (hydrothermal) processes, which produced fissures, pits, flows, and channels with streamlined islands, respectively. This formation model is consistent with the traditional model of Martian fossae-sourced channel systems, where both lava and water were transported along these same channels, in some cases multiple times forming potential habitats. We also considered a lava flow formation model for the observed features. We determined the approximate age of the channel-forming activity to be Late Amazonian, contemporaneous with other, distinctly lava flow processes in the Tharsis region.

The Geology of the Navua Valles Region of Mars

ABSTRACT The Navua Valles are a system of channels and valleys on the inner rim of Hellas Basin. The aim of this mapping study was to determine the geologic history of the Navua Valles region; and the relationships between the basement, flow, and channel units along the northeastern slope of Hellas Basin. We have produced a 1:1 million scale geologic map of the Navua Valles region, utilizing standard USGS geologic mapping procedures, but not within a regular USGS mapping project. We selected the mapping area boundaries specifically to cover the Navua Valles drainage systems. The primary base of this mapping effort was a mosaic of 161 Mars Reconnaissance Orbiter Context Camera images, at approximately 6 m/pixel. This paper is part of a double publication, one paper describing the geology of this area, and this paper presenting the geologic map produced during the investigation.

Paleolakes of Northeast Hellas: Precipitation, Groundwater-Fed, and Fluvial Lakes in the Navua–Hadriacus–Ausonia Region, Mars

The slopes of northeastern Hellas Basin, Mars exhibit a wide variety of fluvial landforms. In addition to the Dao-Niger-Harmakhis-Reull Valles outflow channels, many smaller channels and valleys cut into this terrain, several of which include discontinuous sections. We have mapped these channels and channel-associated depressions to investigate potential paleolakes from the Navua Valles in the West, through the Hadriacus Mons volcano in the center, to the Ausonia Montes in the East. We have identified three groups of candidate paleolakes at the source regions of major drainages and a fourth paleolake type scattered along the lower reaches of these drainages. Each paleolake group has a distinct character, determined by different formative processes, including precipitation and groundwater for lakes at the channel sources, and fluvially transported water at the lower channel reaches. Only one of these 34 basins had been cataloged previously in paleolake basin databases. Several of these sites are at proximity to the Hadriacus volcanic center, where active dikes during the Hesperian could have produced hydrothermal systems and habitable environments. Deposits within these paleolake depressions and at the termini of channels connected to these candidate paleolakes contain the geological and potentially biological record of these environments.