Basal erosion and surface heat flux anomalies associated with plume-lithosphere interaction beneath continents
Authors: Heyn Björn , Conrad Clinton 
Published: March 2022

&lt;p&gt;&lt;span&gt;Deep-seated upwellings within the Earth&amp;#8217;s mantle, &lt;/span&gt;&lt;span&gt;also known as&lt;/span&gt;&lt;span&gt; mantle plumes, affect the &lt;/span&gt;&lt;span&gt;Earth&amp;#8217;s&lt;/span&gt;&lt;span&gt; surface &lt;/span&gt;&lt;span&gt;by inducing&lt;/span&gt; &lt;span&gt;(&lt;/span&gt;&lt;span&gt;large-scale&lt;/span&gt;&lt;span&gt;)&lt;/span&gt;&lt;span&gt; volcanism, &lt;/span&gt;&lt;span&gt;initiating &lt;/span&gt;&lt;span&gt;continental breakup and &lt;/span&gt;&lt;span&gt;increasing &lt;/span&gt;&lt;span&gt;surface heat flow. &lt;/span&gt;&lt;span&gt;P&lt;/span&gt;&lt;span&gt;lume-lithosphere interaction may &lt;/span&gt;&lt;span&gt;also generate&lt;/span&gt;&lt;span&gt; lithospheric erosion &lt;/span&gt;&lt;span&gt;at the base of the tectonic plates&lt;/span&gt;&lt;span&gt;.&lt;/span&gt;&lt;span&gt; It is therefore &lt;/span&gt;&lt;span&gt;important to understand the past positions and movements of mantle plumes relative to &lt;/span&gt;&lt;span&gt;the &lt;/span&gt;&lt;span&gt;surface plates. However, w&lt;/span&gt;&lt;span&gt;hile hotspot tracks beneath thin oceanic lithosphere are visible as volcanic island chains, the plume-lithosphere interaction for thick continental or cratonic lithosphere often remains hidden due to the lack of volcanism. &lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;To identify plume tracks with missing volcanism, we characterize the relationship and timing between plume-lithosphere interaction and associated surface heat flux anomalies by using numerical models of mantle convection. &lt;/span&gt;&lt;span&gt;Our results indicate a &lt;/span&gt;&lt;span&gt;relation&lt;/span&gt;&lt;span&gt; between lithospheric thinning and surface heat flux anomaly, which &lt;/span&gt;&lt;span&gt;is independent o&lt;/span&gt;&lt;span&gt;f&lt;/span&gt;&lt;span&gt; geometry and &lt;/span&gt;&lt;span&gt;can be &lt;/span&gt;&lt;span&gt;approximated analytically. &lt;/span&gt;&lt;span&gt;We have confirmed this close &lt;/span&gt;&lt;span&gt;link between basal erosion of the lithosphere and surface heat flux anomaly using an analytical expression form the time-dependence of heat transmission through convectively thinned lithosphere.&lt;/span&gt; &lt;span&gt;Anomaly &lt;/span&gt;&lt;span&gt;amplitudes primarily depend on the viscosity structure of the lower lithosphere and the asthenosphere, &lt;/span&gt;&lt;span&gt;with a minor dependence on plume temperature&lt;/span&gt;&lt;span&gt;. &lt;/span&gt;&lt;span&gt;L&lt;/span&gt;&lt;span&gt;ithospher&lt;/span&gt;&lt;span&gt;ic&lt;/span&gt;&lt;span&gt; thinning is strongest around the time the plate is above the plume conduit, while the maximum heat flux anomaly occurs about 40-140 Myr later. Therefore, continental and cratonic plume tracks can be identified by lithospher&lt;/span&gt;&lt;span&gt;ic&lt;/span&gt;&lt;span&gt; thinning, even if they lack extrusive and intrusive magmatism, followed by &lt;/span&gt;&lt;span&gt;elevated surface heat flux several 10s of Myr later.&lt;/span&gt; &lt;span&gt;This has important implications, especially for arctic settings such as Greenland or Antarctica, as ice melting rates might be affected &lt;/span&gt;&lt;span&gt;by elevated heat flow&lt;/span&gt;&lt;span&gt; long after the plume passage.&lt;/span&gt;&lt;/p&gt;