Craton control on sediment-hosted metal deposits in continental rifts
Authors: Glerum Anne , Brune Sascha , Magnall Joseph , Weis Philipp , Gleeson Sarah 
Published: February 2023

&lt;p&gt;Many large sediment-hosted base metal deposits occur in failed continental rifts and the passive margins of successful rifts, e.g., in the MacArthur Basin (Australia), and in the Selwyn Basin (Canada). The large-scale geodynamics control the parameters involved in metal leaching and deposition on smaller spatial and temporal scales. Such parameters include 1) the supply of syn-rift siliciclastic sediments from the rift shoulders to form potential source rocks, 2) elevated temperatures and heat flows supporting metal leaching by fluids, 3) fault networks facilitating hydrothermal fluid flow, and 4) organic rich siliciclastic host rocks.&lt;/p&gt;
&lt;p&gt;Analysis of the occurrence of base metal deposits and lithospheric thickness has shown that the majority of deposits are located within 200 km of a craton edge (Hoggard et al. 2020). Numerical models have also shown that a craton close enough to an incipient rift controls the asymmetry of the rift system (Andres-Martinez 2016). We therefore investigate how the presence of a craton controls the development of environments favorable for metal leaching and deposition in rift basins.&lt;/p&gt;
&lt;p&gt;To this end, we use the geodynamic code ASPECT (Kronbichler et al. 2012; Heister et al. 2017) coupled to the landscape evolution model FastScape (Braun and Willett 2013; Neuharth et al. 2022) to model 2D rift systems from inception to break-up in the presence of a craton. With these high-resolution (~150 m) simulations, we investigate the relationship between craton distance and thickness and the area of potential source rock and host rock, where metals could be leached and deposited, respectively. We subsequently analyse the co-occurrence of such source and host rock and potential faulting events connecting them (e.g., Rodr&amp;#237;guez et al. 2021).&lt;/p&gt;
&lt;p&gt;Preliminary results show that the close presence of a craton leads to predominantly asymmetric systems with a narrow craton-side margin (as shown by Andres-Martinez 2016). A craton also increases the amount of potential source and host rock. Whereas the amount of source rock increases with distance between craton and rift, the total area of potential host rock decreases. Furthermore, the co-occurrence of source, host and faults in one subbasin is rare.&lt;/p&gt;
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&lt;p&gt;Andres-Martinez, M. 2016. PhD thesis, Royal Holloway University of London.&lt;/p&gt;
&lt;p&gt;Braun, J. and S. D. Willett. 2013. &lt;em&gt;Geomorphology&lt;/em&gt; 180&amp;#8211;181: 170&amp;#8211;79. DOI: 10.1016/j.geomorph.2012.10.008.&lt;/p&gt;
&lt;p&gt;Heister, T. et al. 2017. &lt;em&gt;Geophys. J. Int.&lt;/em&gt; 210 (2): 833&amp;#8211;51. DOI: 10.1093/gji/ggx195.&lt;/p&gt;
&lt;p&gt;Hoggard, M. et al. 2020. &lt;em&gt;Nature Geoscience&lt;/em&gt; 13 (7): 504&amp;#8211;10. DOI: 10.1038/s41561-020-0593-2.&lt;/p&gt;
&lt;p&gt;Kronbichler, M. et al. 2012. &lt;em&gt;Geophys. J. Int.&lt;/em&gt; 191 (1): 12&amp;#8211;29. DOI: 10.1111/j.1365-246X.2012.05609.x.&lt;/p&gt;
&lt;p&gt;Neuharth, D. et al. 2022. &lt;em&gt;Tectonics&lt;/em&gt; 41 (3): e2021TC007166. DOI: 10.1029/2021TC007166.&lt;/p&gt;
&lt;p&gt;Rodr&amp;#237;guez, A. et al. 2021. &lt;em&gt;GCubed&lt;/em&gt; 22 (6). DOI: 10.1029/2020GC009453.&lt;/p&gt;