The geologic history of Margaritifer basin, Mars

Abstract

In this study, we investigate the fluvial, sedimentary, and volcanic history of Margaritifer basin and the Uzboi‐Ladon‐Morava outflow channel system. This network of valleys and basins spans more than 8000 km in length, linking the fluvially dissected southern highlands and Argyre basin with the northern lowlands via Ares Vallis. Compositionally, thermophysically, and morphologically distinct geologic units are identified and are used to place critical relative stratigraphic constraints on the timing of geologic processes in Margaritifer basin. Our analyses show that fluvial activity was separated in time by significant episodes of geologic activity, including the widespread volcanic resurfacing of Margaritifer basin and the formation of chaos terrain. The most recent fluvial activity within Margaritifer basin appears to terminate at a region of chaos terrain, suggesting possible communication between surface and subsurface water reservoirs. We conclude with a discussion of the implications of these observations on our current knowledge of Martian hydrologic evolution in this important region.

Widespread exposure of Noachian phyllosilicates in the Margaritifer region of Mars: Implications for paleohydrology and astrobiological detection

“…Detailed geologic mapping has been completed over parts of the region by Irwin and Grant [] (Holden crater northward to central Ladon basin) and Salvatore et al . [] (Margaritifer basin) and is in progress for regions south and west of Ladon basin [ Wilson et al ., ; Weitz et al ., ]. These and other studies have shown a complex geomorphological history, the observable features of which can be broadly summarized as follows: Noachian: The Chryse trough formed north‐south through the region in response to the lithospheric load of the Tharsis volcanic province [ Phillips et al ., ].…”

“…Further sediments and fluid were introduced into Margaritifer basin by the Samara and Parana‐Loire valley systems to the southeast [ Grant and Parker , ; Salvatore et al ., ] and into Ladon basin from centripetally draining valleys [ Irwin and Grant , ]. Layered, clay‐bearing units have been identified in the basins [ Milliken and Bish , ; Salvatore et al ., ], in Uzboi and Ladon Valles [ Grant et al ., ] and in Eberswalde [ Rice et al ., ] and Holden [ Grant et al ., ] impact craters. These may have been deposited during ponding episodes, with the clays either forming authigenically or through erosion and transport from upstream Noachian units or impact crater/valley walls [ Grant et al ., ].…”

“…These may have been deposited during ponding episodes, with the clays either forming authigenically or through erosion and transport from upstream Noachian units or impact crater/valley walls [ Grant et al ., ]. Sediment deposition was followed by volcanic resurfacing in Margaritifer [ Salvatore et al ., ] and Ladon [ Irwin and Grant , ] basins. Late Hesperian to Amazonian: Surface collapse (the causes of which are debated [e.g., Carr , ; Cabrol et al ., ; Hoffman , ]) formed multiple regions of chaos, where the surface was down‐dropped and fractured into blocks. Iani and Margaritifer Chaos formed across the path of the ULM system and were major sources of Hesperian‐to‐Amazonian water outflow northward into the Chryse basin through Ares Vallis [ Carr , ; Grant and Parker , ; Warner et al ., ].…”

“…The specific geological history of Margaritifer Terra, near Mars' hemispheric dichotomy boundary, gives it an exceptionally high potential for formation and later exposure of such units. Its topographic setting caused it to be a sink for sediments and fluid in the Noachian‐to‐Early Hesperian periods [ Hynek and Phillips , ; Milliken and Bish , ], resulting in the emplacement of clay‐bearing units apparently deposited in low‐energy environments conducive to preservation of evidence for life [ Grant et al ., ; Salvatore et al ., ]. Subsequently, the surface was extensively disrupted during the Late Hesperian‐to‐Amazonian periods [ Tanaka et al ., ], potentially exposing these early terrains to a greater degree here than in the more geologically stable southern highlands.…”

Large‐scale fluid‐deposited mineralization in Margaritifer Terra, Mars

“…Moreover, Hesperian lava units have been identified in the Margaritifer [Salvatore et al, 2016] and, perhaps, Ladon [Irwin and Grant, 2013] basins. Moreover, Hesperian lava units have been identified in the Margaritifer [Salvatore et al, 2016] and, perhaps, Ladon [Irwin and Grant, 2013] basins.…”