Bright highlands in equatorial Venus likely ferro-electric. What's up with the high-latitude highlands?

Overview

A lot of papers have been written about the highly reflective highlands (in radar) on Venus, with several different hypotheses (e.g. high porosity, metal frost).  Allan Treiman, Elise Harrington, and Virgil Sharpton look specifically at high-latitude highlands in comparison to highlands in the equatorial regions.  Both areas feature high reflectivity, but the reflectance patterns are distinct, as they describe in Venus' radar-bright highlands: Different signatures and materials on Ovda Regio and on Maxwell Montes.

What Did They Find?

They have confirmed earlier studies showing that the reflectance pattern seen in equatorial highlands

"Snow Line" from N flank of Maxwell Montes (from Fig. 4c)

(such as Ovda Regio) are consistent with a ferro-electric substance, likely chlorapatite.

The reflectance patterns on Maxwell Montes (~60°N) are different.  The backscatter abruptly transitions from low to high at the previously identified "snow line" (~4.5km elevation), and stays high above that point.

They believe this pattern indicates a semiconductor material.  How did it get there? Either by precipitation from the atmosphere (frost?), or it formed as the result of a chemical reaction between the surface and atmosphere.

Why Is It Important?

At the very least, their research shows that even though the highlands of Ovda Regio (equatorial) and Maxwell Montes (high latitude) are similarly reflective, they are caused by different materials or processes.

The authors urge (and I agree) that lander missions with geochemical analysis instruments be sent to multiple highland locations.

References:

• Treiman, A., Harrington, E., & Sharpton, V. (2016). Venus’ radar-bright highlands: Different signatures and materials on Ovda Regio and on Maxwell Montes Icarus, 280, 172-182 DOI: 10.1016/j.icarus.2016.07.001