11 November 2022
How the Mountains Grew, by John Dvorak
Posted by Callan Bentley
This enjoyable book offers “a new geological history of North America,” summarizing a vast swath of research from many disciplines to expound on the continent’s evolution over deep time. The geographic scope is a little inconsistent – it mainly centers on the Lower 48 United States, but includes bits of Canada and a brief foray into Mexico for the Chicxulub impact crater, but also mentions Hawaii (which though part of the U.S. isn’t part of the continent) while almost entirely ignoring Alaska. But for the areas it focuses on as relevant to telling the story of the continent, it delves into great, highly-specific detail: the kind of detail that appeals greatly to a geoscience outreach nut like me. Specific waterfalls in state parks, specific exit numbers to reach key outcrops, this glacier has retreated by that many miles, and so forth — all this is evidence of a willingness to luxuriate in the level of geographic detail that might put a novice off, but suggests to me that Dvorak really knows what he’s talking about. Then again, there were some errors that seemed preventable: placing India in the northern hemisphere at the time of the Deccan Traps’ eruption, mistakenly referring to the Coastal Plain as “the Piedmont,” indicating that Mt. Moran’s 800 Ma mafic dike was intruded “near the end of the Paleozoic.” Maybe these are pretty minor in the grand scheme of things – the book is PACKED with details, and it’s probably inevitable a few of them might not be exactly on target. I found much to appreciate in How The Mountains Grew: new fossils to check out, new parks to put on my “must visit” list, new perspectives on large scale teleconnections between disparate phenomena. I’d never heard of Dvorak’s writing prior to seeing this volume pop up in a “related books” algorithm on AbeBooks.com, and I’m so glad it did. Turns out he has three other titles, which I just ordered — and look forward to reporting on them to you here someday!
Skipped the terrane wreck?
https://www.sciencedirect.com/science/article/abs/pii/S0012821X01005167
Yep
I have read 100 books on geology for fun. Dvorak’s book was next in line. Not being a geologist I don’t understand that much but I do become perplexed when I read about a geology subject and remain puzzled about what I read. On page 231 (last paragraph) of How the Mountains Grew there is a discussion about glass beads found near Trinidad Co. “sandwiched between two coal seams”. (I have collected them west of Raton NM). After I read this I Googled it and found pics of the “silvery layer” sandwiched immediately between two coal seams.
My question to anyone who believes there is any relevance to it is: if after the meteor struck, the earth burned then cooled, how could there be a coal seam immediately above the silvery layer?
Secondly, was the coal seam immediately below the silvery layer exposed on the surface at the time the silvery layer fell to earth? If so, then what happened that allowed the coal seam to immediately bury the silvery layer after it fell?
Presumably the Colorado site was a swamp, and remained wet and a site of deposition before, during, and after the impact. Before and after deposition was dominated by organic plant remains. During, by ejecta/fallout.
I thought that name sounded familiar. I loved “The Last Volcano.”
Good to learn about this more recent book.