Tessera

Some news about Venus' tesserae. They're rugged badlands, first noted by the Soviet Union when they were messing up their radar. Paul Byrne's press release comes with an image from Tellus Regio ("Regio" means "highland" here), which hosts one (or more - see below) of these formations. The conclusion: they formed ~750 Mya, and are layered. On the assumption that Venus was waterless even then, the authors conclude: volcano.

They don't know if Venus then was waterless. Some studies claim Venus used to be moist. Recent studies see phospane in the sky and wonder if there is (now!) life over this planet, and if it came from Venus or else hitched from our planet.

Other research has looked in on Tellus particularly. I give to you M.S. Gilmore and J.W. Head doi 10.1016/j.pss.2018.02.001 from two years back: "Morphology and deformational history of Tellus Regio, Venus: Evidence for assembly and collision". First came three independent tesserae; then the three collided to form this Regio. This agrees with Byrne inasmuch as tesserae are ancient and other formations, secondary. For those speculating about sediments however, I'd not uplift my hopes: this Regio is associated with shifting crust later - mantle downwelling per Gilmore-Head. I think it kicked off its career with geothermics earlier.

Tellus itself isn't one of our more famed Regiones. It is nothing like Ishtar let alone Maxwell. I am unsure it even breaches the supercritical ocean, at 3 km over the surface. But elsewhere: tesserae underlie the bulk of Ishtar and Aphrodite both.

If Ishtar is mostly a basalt, bubbled up from the mantle, this implies the mining should be rich there.