w/CS: The Ends of the World, Peter Brannon

The Ends of the World: Volcanic Apocalypses, Lethal Oceans, and our Quest to Understand Earth’s Past Mass Extinctions. Peter Brannon. 2017

April – June 2023

Summary of Periods and Mass Extinctions

Edicarian: 635-538. First appearance of wide-spread multi-cellular organisms in ocean: Soft-bodied microbial organisms forming mats and other structures, and free-floating filter feeders.
End-Edicarian extinction: ~448. 86% species went extinct.* Possibly due to advent of burrowing organisms that disrupted largely sessile ecosystem. Not an official mass extinction because of a very incomplete fossil record.
Cambrian: 538-485. Warm shallow seas flank margins of several continental remnants of the breakup of the supercontinent Pannotia. In ocean there is the advent of hard-bodied complex organisms, and subsequent explosion of diversity into all phyla known today. The land bare except for microbial crust; arthropods and mollusks begin to adapt to life on land towards the end of this period.
Ordovician: 485 – 433. High CO2 levels and continents inundated with vast shallow seas jammed with life: brachiopods; trilobites; cephalopods; eurypterids; grapholites; and jawless fish. Many isolated continents and islands, with continents at south pole and a global sea occupying most of the northern hemisphere. First spores of land plants (fungi and simple plants) at 467Ma, with their spread possibly releasing phosphorous into the ocean stimulating algal blooms and CO2 sequestration.
End-Ordovician extinction:~345 Ma. 75% species went extinct.* Major ice age, likely precipitated by biogenic CO2 depletion, followed by a whip-lash of warming.
Silurian: 443-419. Gondwanaland and island chains provide diversity of environments; in the ocean early fish diversify into jawed and bony fish. Terrestrial life expands in the Silurian-Devonian Terrestrial Revolution: vascular plants emerge from more primitive land plants, and three groups of arthropods (myriapods, arachnids and hexapods) became fully terrestrialized.
Devonian: 419-359. Gondwana supercontinent in the south, Siberia to the north, and Laurussia to the east. Free-sporing vascular plants form extensive forests (Archaeopteris); by the middle of the Devonian several groups have evolved leaves and true roots; by the end the first seed-bearing plants appear.
Late-Devonian extinction event: ~250 Ma. 96% species went extinct.* Two major extinction pulses, and many smaller pulses. One theory is that it is due to the release of nutrients by the punctuated spread of land plants as they developed vascular systems with leaves and roots, and seeds.
Carboniferous: 359-299. Age of amphibians — also first appearance of amniotes from which both reptiles and mammals came. Vast rainforests covered the land, and insects diversified. The latter part of the Carboniferous experienced glaciations, low sea level, and mountain building as the continents collided to form Pangaea. A minor marine and terrestrial extinction event, the Carboniferous rainforest collapse, occurred at the end of the period, caused by climate change
Permian: 299-251. On land: The Carboniferous rainforest collapse left behind vast regions of desert in the continental interior. Amniotes, which could better cope with the conditions, diversified into the synapsids (the ancestors of mammals which came to dominate the Permian) and the sauropsids (reptiles). . In the ocean fish diversify with placoderms dominating almost every known aquatic environment, alongside coeleocanths, with sharks and bony fishes on the sidelines.
End-Permian extinction: 251.9 Ma. 80% of species went extinct.* The Siberian Traps were created at 252 Ma and also interacted with the Tunguska sedimentary basin filled with carbonates, shale, coal and salt in layers up to 12 Km thick; it is the worlds largest coal basin. When the magma intersected the basin, it caught fire, detonated in multiple places, and released vast about of CO2 and methane, on top of the CO2 produced by the eruption contributing to global warming and ocean acidification and anoxia. Other chemicals produced by the incineration of the Tunguska basin contents may have destroyed the ozone layer.
Triassic: 252-201. Brannen argues for a long 5 – 10 million year recovery, but that is disputed. The ancestors of crodcodiles dominated the Triassic; ancestors of dinosaurs and first true mammals appear, but were not dominant. The global climate during the Triassic was mostly hot and dry. Pangea had deserts spanning much of its interior until ita began to gradually rift into Laurasia and Gondwana to the south. In line with this the climate shifted from hot and dry to more humid, with a massive rainfall event called the Carnian Pluvial Event that lasted a million years.
End Triassic Extinction: 200 Ma. 80% of species went extinct.* Volcanism from the rifting of Pangea produced flood basalt that covered more than 4 million square miles. The CO2 concentration doubled or tripled, raising the already warm temperatures by at least 3 ° C. The final extinction pulse was fast: on the order of 20,000 years.
Jurassic: 201.4 – 145. Gondwana begins to rift. Climate warm and humid.
Cretaceous: 145 – 66. Gondwana completes rifting and by the end of the period today’s continents are recognizable, but with shallow inland seas in North America and Africa and between Greenland and Norway.
End Cretaceous Extinction: xxx. 76% of species went extinct.* Most likely some combination of the eruption of the Siberian Traps and the Chixtulub impact lead to global warming and an extended period of darkness. Almost all large animals eliminated, including all dinosaurs excerpt ancestors of birds.

Percent of species that went extinct, for any one event, vary considerably among sources. These numbers are better read as an indicator of relative severity.

Notes on Graphic Granite and Perthitic Textures

While I am used to thinking of granite as an evenly but coarsely textured rock consisting of quartz, feldspars and micas, it is also the case that it can take on very different appearances.

One reason for a different appearance may be that the composition varies from ‘prototypical’ granite, say, with more feldspar, or more quartz, etc. Basically, if one moves around the QAPD diagram, variations in composition can lead to different appearances.

A second reason for a different appearance may be that in the case of certain minerals — Feldspars (and apparently quartz as well) – they may be comfortably intermixed at higher temperatures and pressures, but as they cool (either slowly, or in the presence of water), the may pass through a phase where the different minerals become immiscable and sort themselves out (exsolution), resulting in a distinctive texture. Examples below.

Writing Exercises, 1 (From OBE)

I am trying to focus more on applying what I notice in reading essays to my own writing. Here are a set of prospective exercises I’ve generated after re-reading selections from the Oxford Book of Essays with KC :

Superposition. Providing differing points of view on the same thing/event/space to convey uncertainty/ambiguity. [cf. The Haunted Mind, Note 3, offers alternate PoVs: Is the sound of the bell from the dream or the world? Is the author is in the space of the dream or are the dream figments in the bedroom?]
Minor Key Interlude. A description of a train of thought, or conversation, that in response to some happenstance moves into a minor – dark, distressing, depressing – mode, and then, through more happenstance or perhaps intentional effort, moves back out of it. Attend to the inflection points. [cf. The Haunted Mind, Note s 6 & 7, where hypnagogic turn dark when being swaddled in bedclothes evokes a corpse in a shroud, and then attention to everyday objects serves to vitiate that line of thought].
Animated Trajectory through Three-space. Convey the sensation of a 3D environment by allusions to its structure; by agents moving through it; by objects falling and bouncing; by sound. [cf. The Acorn-Gatherer, Note 2, on the rooks moving about in the tree].
Persuasion via vivid description and inserting oneself into the scene. Vividness, particularity and layering of detail makes a description more convincing, and then with the describer injects themselves into the scene as describes themselves in the act of seeing and feeling. [cf. The Clergyman (Beerbohm)]
Zoom in from Safe Distant Anonymity to Too-Close Intimate Proximity. Zoom in on people interacting. Begin with a comfortable distant overview (e.g. momentary distant glimpses), and then zoom in to show the fine-structure of intimate and not-entirely-easy interaction, whether wanted or not (e.g. continuous up-close eye-contact). (cf. Insouciance.)

Notes on the Geology of Baja

Wednesday, 7 December 2022

Summary

200 Ma, on: Subduction of the Farallon plate resulted in arc volcanism that produced a range of mountains along the west coast of North America. (These will eventually erode, and their batholiths will be exhumed and form today’s mountains and the eroded sediment will accumulate in basins forming soil and lithifying into sedimentary rock.)
20 Ma. As the Farallon plate completed its subduction, it broke into microplates, and
(1) SAFS. the East Pacific Rise subducted initating the transformation of a convergent margin into a transform margin and the San Andreas Fault system, and
(2) Cabo volcanoes. continued subduction of the microplates produced volcanism that can be seen around Cabl
~17 Ma. Complex tectonics, due to the SAF system, that I don’t really understand, generated the basin and range system farther north, and this in turn is thought to have channelized the stress that eventually opened the gulf of California.
~15 – 6 Ma. Tectonics lead to capture of Baja by Pacific plate, transitional shearing in the proto-Gulf of California, and at 6 Ma the beginning of the ‘unzipping’ of Baja.
~3.5 Ma. Development of spreading centers in the Gulf of California, and extrusion of mostly basaltic oceanic crust.

What is this Rock, 3: Course Notes

What is this Rock, 3

I just returned from a weekend up on the North Shore. K and I went up and stayed at Cove Point Lodge, while I took a 3-day course on North Shore Geology, focusing on the Beaver Bay area. The course was taught by Jim Miller, a retired Minnesota Geological Survey person, and an emeritus professor from UMD: he was a great person to teach the course, both because he was a good and enthusiastic instructor, and because he has spent his career focused on the northern Minnesota in general, and the North Shore in particular. Many of the geological maps of the north shore include his name as cartographer.

This is a laundry list of what I learned — however, there are problems with the images which I have yet to fix.

Iceland 2020, Day 1: Reykjanes Plans

Tuesday, 26 July 2022

While I had intended to report on the trip in this blog, it turned out, since I was writing on my phone, to be easier to do a series of daily posts to Facebook. So this is the last bit on Iceland here, at least for the moment. I plan to edit and expand the FB posts, and will eventually post them here, or in a another of my blogs.

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Geology of the Peninsula*

*Much of this is adapted from https://en.wikipedia.org/wiki/Geology_of_Reykjanes_Peninsula

The Reykjanes Peninsula is the continuation of the submarine Reykjanes Ridge, a segement of the Mid-Atlantic ridge. It reaches from the Esja volcano in the north to hengill in the east and Reykhanesta in the west. It originated 6-7 Ma in a rift-jump, after the Snæfellsnes-Skagi rift had drifted to the west out of range of the presumed location of the mantle plume.

Iceland 2022, Day 0: Recovery Day in Reykjavik

Monday, 25 July 2022

A good night’s sleep

https://norse-mythology.org/symbols/svefnthorn/Norse Sleep Rune

As I’ve aged I find that I fare less well on less sleep; or perhaps, I never fared well on less sleep, but when young was too inexperienced to notice my own deficits. Regardless, I scheduled my trip to have a ‘recovery day,’ so that I wouldn’t be dragging on the first day of the tour. Additional benefits are decreased stress — I was unconcerned the cascading delays of the day before would cause any disruption in my schedule – and a chance to wander about Reykjavik.

Iceland 2022, Travel Day: The Yellow Duffle

Saturday-Sunday, 23-24 July 2022

I have been looking forward to the Iceland trip for quite a long time. It had initially been scheduled for the Summer of 2021, but Covid concerns derailed that. The trip is under the auspices of ILSG –The Institute of Lake Superior Geology – which is a regional association of geologists, both professional and academic. I became acquainted with the group via the Geological Society of Minnesota, and went on an ILSG field trip to the big island of Hawai’i in the winter of 2020, just prior to the advent of Covid. It was a great trip, 11 days with about a dozen folks, and toured the five extant volcanoes of the island, including a helicopter trip to the suburb once known as”Royal Gardens,” now better known as a lava field of black basalt. It was a great trip, and although I am introverted, I very much enjoyed the trip and the people. That the people who led the Hawaii trip were also leading the longer and rougher Iceland trip, was a significant inducement.

Yosemite Trip, June 2022

Monday, 13 & 20 June 2022

I had a wonderful time in Yosemite. Five days, each of which ended in pleasant exhaustion. Some beautiful hikes; and none that I regret. More detail below.

Snow Creek
Lower Gaylor Lake
Polydome area
Three moraines in the Valley
May Lake towards Glen Aulin; and Lukens lake

Things I learned from the 2021 Loft Essay course

16 August 2021

Things to pay attention to:

Telling details: One telling detail is preferable to many details
Embodiment. Emotions and actions work best when embodied: gaze, gesture, posture, proprioception, proxemics
Scenes. Scenes should vary in length, and be interleaved with summaries. This gives rhythm and weighting. Think of a scene as a spotlight.
Language: avoid ‘to be’s. Avoid “is” “are” “have” etc. and limit use of adjectives.
“To be” is the weakest verb. Not “He is tall” but “He smacked his head on the door frame”
Language: avoid distancing: Avoid habitually using filtering/distancing language such as “I noticed,” “I heard,” “I saw,”
(That said, sometimes you may want to use it to distance yourself, as when you are uncomfortable and don’t want to be in it.)
Language: avoid adverbs. Use actions and embodiment rather than adverbs:
“Yeah,” she said, stroking his bare arm, “that’s what I heard.” vs. “Yeah,” she said gently, “that’s what I heard.”
Support reader inference. There is something about readers being able to figure something out on their own that is very rewarding.
Revising Tricks: Print it out in a different font. Read it out loud and notice where you stumble, speed up, lag, etc. Replace “to be’s”

What I’ve Learned from Critiquing SF&F

Wednesday, 21 July 2021

These are observations on what works, from critiques I made during my Summer 2021 Worldbuilding Course