20 April 2016

Cooling columns of the Catoctin Formation, Indian Run Overlook, Shenandoah National Park

It’s National Park Week, which means free entrance to our nation’s many wonderful national parks. My local park is Shenandoah National Park, astride the Blue Ridge one mountain range over from my house. Monday was parent/teacher conferences at my son’s school, which meant I had to look after him all day. We had a great time together up on Skyline Drive, searching for spiders, making GigaPans, and having a picnic. The weather was great. We saw a black bear and had a great time.

We stopped one place I had never been before: Indian Run Overlook, below the celebrated columns of Compton Peak, where there are some nice cooling columns exposed.


These are primary volcanic structures that formed when a basaltic lava flow oozed out onto the surface of Virginia during the Neoproterozoic breakup of the supercontinent Rodinia. This episode of tectonic rifting is preserved in lava flows like this, the feeder dikes which fed them, and associated pyroclastic deposits (tuffs and volcanic breccias). There are also some immature sedimentary deposits below and intercalated with the volcanic strata. When the lava flows cooled, they solidified. As they cooled further, the freshly-minted warm rocks contracted a bit, and cracked. The pattern of cracks was polygonal on the surface of the flow, but then the fractures propagated downward, dividing the monolithic flow into a set of more-or-less hexagonal ‘columns.’


Here is a GigaPan that my son and I made of the site. See if you can find the scale pencil:


I usually drive by this spot on field trips I lead in Shenandoah National Park, as it’s often obscured by shadows in the late afternoon – a shame, but that’s almost always how the timing works out. But on Monday I discovered that the lighting is really good in the late morning. From now on, I plan to stop every time I get the opportunity during those hours.

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15 April 2016

Friday fold: Shiny pahoehoe

James Farrell is our newest Friday fold source. Today he shares a primary (not tectonic)  fold – the fold is in the ropy texture of a pahoehoe flow:


Those colors! What a gorgeous rock. Thanks for sharing, James!

You, too, can share your folds here. Send me your images. I look forward to featuring them on the Friday fold!

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8 April 2016

The Hidden Half of Nature, by David R. Montgomery and Anne Biklé

hhon David Montgomery is a professor of geomorphology at the University of Washington, in Seattle. I’m a fan of his work in soil conservation and countering creationism, so I was very pleased to find myself sharing the “honoree” table with him in Vancouver the year before last, at the annual awards luncheon for the National Association of Geoscience Teachers and the Geological Society of America’s Geoscience Education Division. I was there as the Biggs Awardee, while Montgomery received the James Shea Award. In his speech, Montgomery told the group that he was working on a new book, a project he was co-writing with his wife, Anne Biklé. The subject was about how microbes mediate almost everything we hold near and dear. That book is now out. It’s called The Hidden Half of Nature: the Microbial Roots of Life and Health. I just finished the audiobook version of it.

The premise of the book is that microbes really matter, and that most of them matter in a positive way – commensalism and mutualism – even though most of our agricultural and medical practice thinks of “germs” as bad, and worthy of biocide. Using an extended analogy between the functioning of their backyard garden and the functioning of the human body, Montgomery and Biklé explore the science of how healthy microbial ecosystems nurture plant growth, nutrition, and productivity, as well as help regulate immune responses in our own bodies. The journey begins as they transform the weedy bare lot of their Seattle home into a vibrant garden – by bringing in huge quantities of organic material and inoculating it with a compost “tea” of useful microbes. Their plants begin to thrive, and this leads the authors to explore the “rhizosphere” – a zone of intense microbial life surrounding and integrated with plant roots in great detail – detail matched later in the book when, after Anne develops cancer, she delves into a similar realm of microbial/macro-organismal cooperation: the colon. There’s a lot of biochemistry in these sections of the book – right at the threshold of my attention span, frankly. But the larger point is valid and clear: we need to embrace a new perspective on soil health and human health: most microbes serve useful, even critical functions. When we sterilize soil or treat our bodies with antibiotics, we can inadvertently eliminate the good bugs along with the “bad.” These microbes do really important things, including triggering certain immune responses and releasing plant growth hormones. On the tiniest level, it’s fascinating to see how much we are controlled by chemicals produced by organisms that we cannot see.

Topics covered range from the development of nitrogen fixing technology to agricultural micronutrient declines over the past century, to the function of the appendix and the evolution of mitochondria. History of science is covered extensively – the discoveries of the first microscopists; the work of Louis Pasteur; hand washing’s initial rejection by the medical establishment. It’s a broad spectrum of topics, but you never feel like they are deviating too far from their chosen subject. Instead, in examining a complex tapestry of interconnectedness, they focus on a thread at a time. It works.

The book is not perfect – the argument is in places redundant, evidence presented is sometimes anecdotal rather than rigorously controlled, and the narration of how the authors were introduced to certain ideas can be tedious (Stuff like: ‘We went on vacation and went to a park and then stopped at this great little pub for tea, and there I picked up a magazine that had an article in it that captured my imagination, which led me to read other articles,’ etc.) but overall the strengths of the book outweigh these critiques. The language is accessible and straightforward, the analogies are strong and simple, and the overall message’s validity is supported quantitatively and qualitatively from dozens of directions. I’m glad to have read it, and already I can see that it has changed my perspective. When I ate breakfast this morning, I was thinking less about what I wanted to taste and more about what sort of “mulch” I wanted to be applying to my inner “garden” of microbes.

Recommended, especially if you haven’t already read Montgomery’s Dirt, or if you know anyone with diseases that result from chronic inflammation.

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7 April 2016

New GIGAmacro images of rock samples

Another week, another batch of new images produced on my home-based Magnify2 imaging system from GIGAmacro.

Leptaena brachiopod in (Mississippian?) limestone from Montana:

Here’s the flip side of the same sample, with a lot of fenestrate bryozoans to see:

Fault breccia from the Corona Heights Fault of San Francisco:

Amygdular metabasalt from the western Sierra Nevada of California:

Araucaria mirabilis gymnosperm cone fossil, from the Cerro Cuadrado Petrified Forest site (Mid-Jurassic) of Argentina:

Glacial striations on a pebble from the latest-Devonian Spechty Kopf diamictite, exposed on Corridor H in West Virginia:

As always, enjoy exploring them for details.

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2 April 2016

Five new GIGAmacro images

Here are a few new images I’ve been working on with my home-based Magnify2 imaging system from GIGAmacro.

Strophomenid brachiopods from Mississippian Mauch Chunk Formation, West Virginia:

Boninite from New Caledonia:

Lepidodendron scale-tree bark from Poland:

Potassium feldspar crystal, from a pegmatite:

Catoctin Formation greenstone from a feeder dike east of Linden, Virginia:

Enjoy exploring them for details.

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31 March 2016

This week’s batch of 3D models

Anorthosite with lovely garnet reaction rims, a spherical hematite concretion, and some sweet breccia. Check them out and explore!

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29 March 2016

Four new GIGAmacro images

Here are a few new images I’ve been working on with my home-based Magnify2 imaging system from GIGAmacro.

Archean basement complex gneiss from the Gallatin Range of Montana:
(If this looks familiar, that’s because one of the samples I imaged with the Photoscan 3D modeling technique and published on Sketchfab the week before last.)

Banded iron formation from Minnesota with ooids and stromatolites:

Intrusion breccia:

Blue Ridge basement complex lineated gneiss with chlorite/quartz vein:
(If this looks familiar, that’s because the same sample was imaged with the Photoscan 3D modeling technique and published on Sketchfab last week.)

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27 March 2016

Another trio of 3D models

Here are three more of my Photoscan-generated, Sketchfab-hosted 3D models of rock samples:

Mud cracks in Tonoloway Formation tidal flat carbonates, Corridor H, West Virginia:

Diorite from the eastern Sierra Nevada of California:

Vein cross-cutting foliated & lineated gneiss, Blue Ridge basement complex, Virginia:

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24 March 2016

Three new 3D rock sample models

Pahoehoe “ropes” on a basalt, sample site unknown:

Archean gneiss from the Gallatin Range of Montana:

Tafoni in Malmesbury Group turbidites, South Africa:

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21 March 2016

Animal, Vegetable, Miracle, by Barbara Kingsolver

avm Here’s a great book about one family’s efforts to eat as locally as possible for a year, sort of. Whether or not they’re evangelical enough in their southwest Virginia locavory (I would have made the same call with regard to olive oil and coffee!), Barbara Kingsolver and her family definitely are certainly inspiring. Their efforts to produce their own food or buy it from their farming neighbors are simultaneously enlightening, informative, and motivating. I recommend this nonfiction account of their year as much as I would recommend any of Kingsolver’s novels. You’ll learn about heritage turkeys, kids running an egg business, the difficult of “going local” when going to college, why asparagus is such a uniquely springtime treat, and why certain dishes are impossible if you’re going to tie your eating to the seasonal availability of produce in your local “foodshed.” I learned a lot – and Kingsolver’s writing is a pleasure to sample. The book is co-written with her husband and eldest daughter, and I thought this made the whole book that much more enjoyable – it’s a family effort depicting a family effort. Top notch.

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