3D Structural modeling of large thrust faults in Warrego Rise (southern Thaumasia) and Phrixi Rupes (Aonia Terra), Mars: implications for the architecture of a thrust fault system concentric to Tharsis.
Authors: Herrero-Gil Andrea , Romeo Ignacio 
Published: September 2022

&lt;p&gt;&lt;strong&gt;&lt;span lang=&quot;en-US&quot;&gt;Introduction&lt;/span&gt;&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;&lt;span lang=&quot;en-US&quot;&gt;The structural modeling of lobate scarps, the topographic effect of surface breaking large thrust faults, have been accomplished by different techniques. 2D Mechanical forward dislocation models (&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;Grott et al., 2007; &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;Ruiz et al., 2008;&lt;/span&gt; &lt;span lang=&quot;en-US&quot;&gt;Egea-Gonzalez et al., 2017&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;, &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;Herrero-Gil et al., 2019&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;) and 2D balance area models (&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;Mueller et al. 2014, &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;Herrero-Gil et al., 2019&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;) were applied to Martian lobate scarps. &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;The r&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;ecent development of robust 3D &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;structural &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;modeling software (&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;MOVE&lt;/span&gt;&lt;sup&gt;&lt;span lang=&quot;en-US&quot;&gt;TM&lt;/span&gt;&lt;/sup&gt;&lt;span lang=&quot;en-US&quot;&gt; software suite, Petroleum Experts Ltd.;&lt;/span&gt; &lt;span lang=&quot;en-US&quot;&gt;used for this study through the &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;Academic &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;L&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;icence &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;of the&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt; Universidad Complutense de Madrid) have allowe&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;d&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt; a more detailed 3D modeling approach that was successfully applied to Og&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;y&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;gis Rupes (&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;Herrero-Gil et al., 20&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;20a&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;) and the Amenthes Thrust Fault System (&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;Herrero-Gil et al., 20&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;20b&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;). Here we show the results of the &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;obtained&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt; 3D structural model&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;s&lt;/span&gt; &lt;span lang=&quot;en-US&quot;&gt;for&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt; 3 thrust faults &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;at&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt; the southern &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;boundary of the Warrego Rise &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;(&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;i.e. the boundary between the Thaumasia highlands and the adjacent Aonia Terra to the South&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;)&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt; and the two main faults that make up Phrixi Rupes (&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;located in &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;Aonia Terra) &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;(Fig.1)&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;.&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&lt;img src=&quot;&quot; alt=&quot;&quot; width=&quot;474&quot; height=&quot;308&quot; /&gt;&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Figure 1.&lt;/strong&gt; Location of the studied thrust fault&lt;/p&gt;
&lt;p&gt;&amp;#160;&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;&lt;span lang=&quot;en-US&quot;&gt;Method&lt;/span&gt;&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;&lt;span lang=&quot;en-US&quot;&gt;The structural modeling procedure consists in a pure geometrical approach assuming volume conservation. &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;T&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;he deformation of the hanging wall is &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;reproduced&lt;/span&gt; &lt;span lang=&quot;en-US&quot;&gt;by fault parallel flow (&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;Egan et al., 1997; Ziesch et al., 2014&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;) and the propagation folding is modeled following the trishear algorithm (&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;Erslev, 1991; Allmendinger, 1998&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;). Full details of the modeling procedure can be found in &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;Herrero-Gil et al. &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;(&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;20&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;20&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;a,&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;b&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;)&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;.&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&amp;#160;&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;&lt;span lang=&quot;en-US&quot;&gt;Structural &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;m&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;odeling of thrust faults &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;at&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt; the southern boundary of Warrego Rise&lt;/span&gt;&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;&lt;span lang=&quot;en-US&quot;&gt;Three faults, producing the main thrusting of Thaumasia's Noachian basement over Aonia Terra, have been modeled in this area &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;(Fig. 2)&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;. The obtained &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;maximum fault slips range between 3366-2431 m, the fault dips of the upper planar part range from 33&amp;#186; to 40&amp;#186;, and the depths of faulting from 13 to 27 km. All the studied faults show listric geometries at depth indicating that they root at a detachment level.&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&amp;#160;&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;&lt;img src=&quot;&quot; alt=&quot;&quot; width=&quot;811&quot; height=&quot;775&quot; /&gt;&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Figure 2.&lt;/strong&gt; 3D model of the Warrego Rise thrust faults&lt;/p&gt;
&lt;p&gt;&amp;#160;&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;&lt;span lang=&quot;en-US&quot;&gt;Structural mod&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;e&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;ling of the thrust faults of Phrixi Rupes&lt;/span&gt;&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;&lt;span lang=&quot;en-US&quot;&gt;Two &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;large&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt; faults generating Phrixi Rupes have been modeled &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;(Fig.3)&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;. Their modeled maximum slips are 2847 m and 801 m, with common dip angles for the upper planar part of 33&amp;#186;-33,6&amp;#186; and depths of faulting ranging from 16 &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;to &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;19 km.&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;&lt;img src=&quot;&quot; alt=&quot;&quot; width=&quot;832&quot; height=&quot;415&quot; /&gt;&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Figure 3.&lt;/strong&gt; 3D model of Phrixi Rupes thrust faults&lt;/p&gt;
&lt;p&gt;&amp;#160;&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;&lt;span lang=&quot;en-US&quot;&gt;I&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;mplications for the Circum-Tharsis tectonic contraction&lt;/span&gt;&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;&lt;span lang=&quot;en-US&quot;&gt;The modeling results of this study together with the model for Ogygis Rupes &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;(&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;Herrero-Gil et al., 20&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;20a&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;) &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;show some remarkable characteristics common to all the studied faults in this area: (1) all the main faults (excluding two subsidiary backthrusts &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;in &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;Ogygis Rupes) show an out-of-Tharsis vergence, (2) all of them have listric geometries at depth suggesting that they root at a detachment &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;plane&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;, (3) the depth of faulting of the main faults &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;gets shallower &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;in an out-of-Tharsis direction. &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;Thus, o&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;ur 3D structural modeling results support &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;a commo&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;n&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt; detachment level for &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;all the modeled structures&lt;/span&gt; &lt;span lang=&quot;en-US&quot;&gt;controlling a thick-skin &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;tectonic style&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;.&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&amp;#160;&lt;/p&gt;
&lt;p&gt;&lt;span lang=&quot;en-US&quot;&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&lt;span lang=&quot;en-US&quot;&gt;Allmendinger, R. &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;(&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;1998&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;)&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;. Inverse and forward numerical modeling of trishear fault-propagation folds. Tectonics 17 (4), 640&amp;#8211;656.&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&lt;span lang=&quot;en-US&quot;&gt;Egan, S.S., Buddin, T.S., Kane, S.J., Williams, G.D. &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;(&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;1997&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;)&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;. Three-dimensional modelling and visualization in structural geology: new techniques for the restoration and balancing of volumes. In: Proceedings of the 1996 Geoscience Information Group Conference on Geological Visualization. In: Electron Geology, 1, 67&amp;#8211;82.&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;Egea-Gonz&amp;#225;lez, I., Jim&amp;#233;nez-D&amp;#237;az, A., Parro, L. M., L&amp;#243;pez, V., Williams, J.-P., Ruiz, J. (2017). Thrust fault modeling and Late-Noachian lithospheric structure of the circum-Hellas region, Mars. Icarus, 288, 53&amp;#8211;68.&lt;/p&gt;
&lt;p&gt;&lt;span lang=&quot;en-US&quot;&gt;Erslev, E. &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;(&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;1991&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;)&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;. Trishear fault-propagation folding. Geology 19, 617&amp;#8211;620.&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;Grott, M., Hauber, E., Werner, S. C., Kronberg, P., Neukum, G. (2007). Mechanical modeling of thrust faults in the Thaumasia region, Mars, and implications for the Noachian heat flux. Icarus, 186(2), 517&amp;#8211;526.&lt;/p&gt;
&lt;p&gt;&lt;span lang=&quot;en-US&quot;&gt;Herrero-Gil, A., Egea-Gonz&amp;#225;lez, I., Ruiz, J., Romeo, I. &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;(&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;2019&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;)&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;. Structural modeling of lobate scarps in the NW margin of Argyre impact basin, Mars. Icarus 319, 367&amp;#8211;380.&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&lt;span lang=&quot;en-US&quot;&gt;Herrero-Gil, A., Ruiz, J., Romeo, I. (2020&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;a&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;). 3D modeling of planetary lobate scarps: The case of Ogygis Rupes, Mars. Earth and Planetary Science Letters, 532, 116004.&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&lt;span lang=&quot;en-US&quot;&gt;Herrero&amp;#8208;Gil, A., Ruiz, J., Romeo, I. (2020&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;b&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;). Lithospheric contraction on Mars: a 3D model of the &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;A&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;menthes thrust fault system. Journal of Geophysical Research: Planets, 125(3), e2019JE006201.&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;Mueller, K., Vidal, A., Robbins, S., Golombek, M., West, C. (2014). Fault and fold growth of the Amenthes uplift: Implications for Late Noachian crustal rheology and heat flow on Mars. Earth and Planetary Science Letters, 408, 100&amp;#8211;109.&lt;/p&gt;
&lt;p&gt;&lt;span lang=&quot;en-US&quot;&gt;Ruiz, J., Fernandez, C., Gomez-Ortiz, D., Dohm, J.M., Lopez, V., Tejero, R. &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;(&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;2008&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;)&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;. Ancient heat flow, crustal thickness, and lithospheric mantle rheology in the Amenthes region, Mars. Earth Planet. Sci. Lett. 270, 1&amp;#8211;12.&lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&lt;span lang=&quot;en-US&quot;&gt;Ziesch, J., Tanner, D.C., Krawczyk, C.M. &lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;(&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;2014&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;)&lt;/span&gt;&lt;span lang=&quot;en-US&quot;&gt;. Strain associated with the Fault-Parallel &lt;/span&gt;Flow algorithm during kinematic fault displacement. Math. Geosci. 46, 59&amp;#8211;73.&lt;/p&gt;