Principles of structural geology on rocky planets

Abstract

Although Earth is the only known planet on which plate tectonics operates, many small- and large-scale tectonic landforms indicate that deformational processes also occur on the other rocky planets. Although the mechanisms of deformation differ on Mercury, Venus, and Mars, the surface manifestations of their tectonics are frequently very similar to those found on Earth. Furthermore, tectonic processes invoked to explain deformation on Earth before the recognition of horizontal mobility of tectonic plates remain relevant for the other rocky planets. These connections highlight the importance of drawing analogies between the rocky planets for characterizing deformation of their lithospheres and for describing, applying appropriate nomenclature, and understanding the formation of their resulting tectonic structures. Here we characterize and compare the lithospheres of the rocky planets, describe structures of interest and where we study them, provide examples of how historic views on geology are applicable to planetary tectonics, and then apply these concepts to Mercury, Venus, and Mars.

Farewell lecture by Professor A. M. Celâl Şengör the developments in geology during the last 40 years I spent at the ITU and ITU's contribution

“…Christian pulled together the experience we thus gained and a paper was published under his first authorship in the festschrift the editor-in-chief Professor Ali Polat (ITU'88) organised in my honour in the Canadian Journal of Earth Sciences (Klimczak et al, 2019)…”

Ali Mehmet Celâl Şengör: A geologist who unravels the histories of continents and oceans

“…Given that the Neoarchean S-type granites in the Western Superior Province were derived from partial melting of synorogenic clastic sedimentary rocks and were emplaced in the vicinity of collision zones, they may serve as a geological marker of some Archean tectonic boundaries. Klimczak et al (2019) discuss the principles of structural geology on rocky planets. They show that although the mechanisms of deformation differ on Mercury, Venus, and Mars, the surface manifestations of their tectonics are frequently very similar to those found on Earth.…”

“…The authors suggest that tectonic processes invoked to explain style of deformation on Earth before recognition of horizontal movement of tectonic plates remain relevant for the other rocky planets. Klimczak et al (2019) discuss and compare the lithospheres of the rocky planets, provide examples of how historic views on geology are applicable to planetary tectonics, and then apply these concepts to Mercury, Venus, and Mars. They infer that structural and tectonic phenomena resulting from shortening and stretching of the rocky cover of these planets are not substantially different from those observed and described on Earth, although the neighboring rocky planets lack plate tectonics.…”

Recent tectonism on Mercury revealed by a global population of small grabens

“…Their formation is widely accepted to result from global contraction caused by secular cooling 2,3 , but could also be attributed to tidal despinning 4,5 , true polar wander 6 or mantle overturn 7 or a combination of some or all of these [8][9][10] . Regardless of the cause(s), numerous studies predict that tectonism on Mercury should still be occurring today 9,[11][12][13][14][15][16][17] , yet the only evidence of recent tectonism on Mercury is the identification of 14 lobate scarps that crosscut Kuiperian (~280 Ma) craters 12 and 39 <10 km-long pristine scarps in the northern hemisphere, observed in Mercury Dual Imaging System (MDIS) 18 narrow angle camera (NAC) images 16 . Evidence for widespread continued movement on other shortening structures has been lacking.Here, we present the results of a global survey of extensional grabens on shortening structures (Figure 1).…”