An assemblage of lava flow features on Mercury

Abstract

[1] In contrast to other terrestrial planets, Mercury does not possess a great variety of volcanic features, its history of volcanism instead largely manifest by expansive smooth plains. However, a set of landforms at high northern latitudes on Mercury resembles surface flow features documented on Earth, the Moon, Mars, and Venus. The most striking of such landforms are broad channels that host streamlined islands and that cut through the surrounding intercrater plains. Together with narrower, more sinuous channels, coalesced depressions, evidence for local flooding of intercrater plains by lavas, and a first-order analysis of lava flow rates, the broad channels define an assemblage of flow features formed by the overland flow of, and erosion by, voluminous, high-temperature, low-viscosity lavas. This interpretation is consistent with compositional data suggesting that substantial portions of Mercury's crust are composed of magnesian, iron-poor lithologies. Moreover, the proximity of this partially flooded assemblage to extensive volcanic plains raises the possibility that the formation of these flow features may preface total inundation of an area by lavas emplaced in a flood mode and that they escaped complete burial only due to a waning magmatic supply. Finally, that these broad channels on Mercury are volcanic in nature yet resemble outflow channels on Mars, which are commonly attributed to catastrophic water floods, implies that aqueous activity is not a prerequisite for the formation of such distinctive landforms on any planetary body.

Extent, age, and resurfacing history of the northern smooth plains on Mercury from MESSENGER observations

“…No conclusive volcanic landforms are identified within the NSP, but morphological and structural evidence is consistent with a volcanic origin for the plains. For instance, the presence of flow-modified channels closely associated with vent-like features in areas near the NSP (Head et al, 2011;Byrne et al, 2013) and extensional tectonic features hosted by volcanically filled impact craters and basins (Freed et al, 2012;Klimczak et al, 2012;Watters et al, 2012) supports the hypothesis that the NSP were formed rapidly by large volumes of high-temperature, low-viscosity lava, a conclusion also consistent with the high-volume, high-effusion style of volcanism predicted for Mercury Head, 2008, 2012). From buried crater rim height estimates, a conservative volume of the NSP is between 4 Â 10 6 km 3 and 10 7 km 3 .…”

“…1b), extends from $50°N to 65°N and $120°E to 220°E and is 1.51 Â 10 6 km 2 in area. NSP1 is connected to NSP2 by flooded craters and a series of broad valleys filled with smooth plains interpreted as volcanically flooded impact-sculpted terrain (Byrne et al, 2013;Hurwitz et al, 2013). The smaller region of smooth plains (NSP2) has contributions of material from both the inferred lava channels and the Caloris exterior smooth plains (Denevi et al, 2013a).…”

Geology of the Raditladi quadrangle, Mercury (H04)

“…Volcanic contribution to the geologic scenario found in the H04 quadrangle is significant. In fact, based on morphological and compositional evidence, the majority of the Smooth Plains found in the quadrangle are volcanic in origin, including deposits found in the northern portion of the quadrangle Byrne et al, 2013;Denevi et al, 2013;Ostrach et al, 2015;Weider et al, 2015) and filling the Caloris basin Weider et al, 2015). Moreover, the Smooth Plains found inside Caloris show distinctive composition with respect to the northern volcanic deposits (Weider et al, 2015).…”

Episodes of fluvial and volcanic activity in Mangala Valles, Mars

“…While there is evidence that turbulent lava flows are locally capable of producing land-forms traditionally associated with fluvial activity (e.g., Baker et al, 1992), a well-accepted example of a large lava-carved feature on Mars has yet to be conclusively identified, making a fluvial interpretation more favorable. However, large lava-carved channels have been purported on Mercury (Byrne et al, 2013).…”