During the boring-billion of our Proterozoic Earth, we're told one reason it was boring was a dearth of tectonics. We had a supercontinent... which would be desert. The tides might not have been strong either because our Moon was stuck there for that span, day after nineteen hour day. Where was erosion, wasn't eroding any nutrients.
That might an oversimplification.
The supercontinent - usually called Nuna, but such of my readers as identify as "anti#woke" may prefer Columbia - erupted into a dike, from below. Igneous rocks store magnetic polarity, and have datable uranium/lead percentages (the constants haven't changed since before this solar-system's nebula). This dike formed in the "north China" craton 1235.6 ± 2.0 Mya (now that is precision). That allows constraint of Laurentia-Baltica-Siberia / Australia-China 1.38 Gya, with Australia making its own way 1.32 Gy. Contemporary with this great dike of China, that rest of Nuna was cracking 1.26-1.22 Gya.
So now Earth had continents again. GEO Girl - who alerted me to the paper - has a few other comments for context. Like, the Archaean might have had supercontinents too... but no tectonics? which make the Archaean a mystery, or perhaps just a Venereal era. Nuna is, then, the first supercontinent as makes sense to tectonic-informed research - as a Gaeology, if you will, rather than as a planetology.
The two-continent era spans 1.342 Gya which is, I think, our chloroplasts. So: why not nitrates then, rather than 800 Mya? GEO Girl doesn't talk about after this paper's scope, but does show a slide 50 seconds in: Earth suffered another Single Lid Episode, after the postNuna continents slammed back into another supercontinent, this one Rodinia (which is better known).
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