Giant impact hypothesis

It has been said (though not in that article) that the Pacific Ocean is the scar of the whack. So if the whack hadn’t happened, would Earth’s crust be all continental? In that case the plates would likely be much less mobile, and most of the big mountains would be volcanic, as on Mars.

Although a big whack may be necessary for plate tectonics as we know it, it’s apparently not sufficient; Mars is also thought to have had one, forming the northern lowlands.

Anita Rowland, a blogger who linked to this humble effort several times in its more energetic first year, died of cancer in December.

(If I were still in the habit of reading blogs, I might have known that before now.)

The puzzlingest search string I’ve seen lately is ice weapons in sherwood maps.