John McPhee, Assembling California

Madness, seriously: it wasn't until the late 1960s that our understanding of geology came to include plate tectonics. Maybe ring that up next time someone slags flat-earthers. Until 1968, pretty much every geologist on the entire planet had a fundamentally incorrect understanding of large-scale geological processes. (We should all know this, I think, even if I'm not sure quite what it should mean.)

More specifically, according to John McPhee, nobody could explain the feral complexity of California's topography and geology until plate tectonics entered broad currency, and even more specifically until the occasion of a 1969 conference, attended by many of the world's structural geologists. As one Eldridge Moores sat there listening to another geology professor, all the pieces of theory came together. Suddenly, to Moore if not to anyone else yet, everything about California's geology became clear.

Moores was struck, in that conference room, by the realization that California isn't really part of North America at all. At bottom, California's geology is instead the still-ongoing, echoing residue of multiple and successive super-massive collisions, as arcs of islands shaped like the Philippines or Japan smashed into and rode up onto the continent's western edge (pp.107-108).

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Huge events like these take time, of course, but they're huge. The largest earthquakes within the San Andreas fault system might take down whole cities, but comparatively, they're puny. Twenty feet of seismic shift, busting up freeways and taking down skyscrapers? Pfft. Weak sauce. Talk to me when you grasp that the mountaintops of the Sierra Nevada were formed at the bottom of the Pacific Ocean.

In explaining this concept McPhee uses almost exactly the same line he did in Basin and Range, but it's so good enough that it'd almost be a shame not to do the reprise: "If by some fiat I had to restrict all this writing to one sentence, this is still the one I would choose: The summit of Mt. Everest is marine limestone" (p.183 in Basin, p.214 in Assembling).

Assembling California follows on McPhee's earlier book Basin and Range, the two of which were five of the shorter books swallowed up, tectonic-like, by his leviathan Annals of the Former World (which I kick myself for still not having read. This summer, by God, this summer). There's never any explaining why a writer develops an expertise in a particular area, these things almost always growing by their own laws, but we're all better off because of McPhee's growth into a pseudo-geologist. I could go on, but either you'll buy into one or more of these books just on the strength of my enthusiasm and these few hints, or the book's already dead to you. If you're tempted at all, pick up a copy, and I swear that you'll turn halfway geological yourself.

And as a bonus, a way nerdy geology video for you, featuring one of the world's great beards (on the suspiciously cherubic face of McPhee's friend, source and hero, Eldridge Moores). You're welcome.


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