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Archive for January, 2011

Graded bedding is one of my favorite features to find in rocks when out hiking. In the rock are details of paleo-orientation (which way was originally up) and what the depositional environment was like. The basic concept to understand is that the heavier/larger sediments settle out first while being deposited and the lighter/smaller sediments settle on top. As I was digging through my fridge to find lunch another geologic food analogy dawned on me. Caesar Dressing is graded bedding! Not the creamy kind though. Next time you get a chance grab a bottle of Caesar dressing and shake it up; this will act as the turbidity current. Over the next few minutes watch as the heavier “sediments” like the salts settle to the bottom of the bottle first. Then watch as the next layer of intermediate sediments like romano cheese, anchovy bits, and spices settle, and finally the vinegars and oils settle on top.

Below are a few quick pictures I took of this process. The last one is annotated to really show the effect.

 

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Aerial Pictures

One of the few enjoyments I get out of flying is looking out of the window at the wide array of landscapes. Flying at 30,000 feet gives me a perspective I don’t often get to experience. Traveling out to southern California in particular gives the window seat a view of rivers, mountains, plains, desert, canyons, and more mountains all in one trip. A few years ago I received a book of photography of many different geologic features taken by a man piloting a two seat prop plane. While my iPhone may not convey the majesty as well as the professionals, here are a few pictures I took this past week from my window seat that I enjoyed.

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Ice Breccia

Today I am in Los Angeles enjoying the beautiful 70 degree weather and sunshine. But last week along the Billy Goat Trail in Maryland I took the picture below. In it the ice sheet had fractured and refrozen with the previous fractured pieces as inclusions. Borrowing a term from John McPhee I am going to call this one: self-containing ice breccia.

Stay warm everyone.

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Norway vs. DC

Today we are going to play a little game of guess the locality. Lucky for you there are only two choices: Norway or Washington D.C. The pictures from Norway are going to be from the village of Geiranger that has been mentioned here before, and the D.C. pictures are from the Billy Goat Trail technically in Maryland upriver from the capital.

What ties these two locations together is they were both formed under similar processes at approximately the same time. The mountains found in Norway are the eastern cousins of the Appalachians. The Norwegian mountains formed during the Caledonian orogenies, which occurred in phases much like the Appalachians. The first phase is known as the Finnmarkian where an island arc or small microcontinent collided with what is now Norway. Around the same time, a volcanic island arc collided with North America during the Taconian Orogeny. The effects of both events metamorphosed the rock and folded the different layers. It is up to you to determine which picture uses the dollar or the krona.

Let’s begin!

For you wanna be cheaters out there, I used the same sense of scale in each photo and blackened out the reflection to hide any clues.

#1

#2

#3

#4

#5

If you would like to have a guess, please post your answers in the comments section. I will post the answers there in a few days. Good luck, and I hope you enjoy.

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Great Quote

The following quote was brought to my attention by my father. It is from the author Simon Winchester while discussing volcanoes:

“…man lives on this planet subject to geological consent which can be withdrawn at any time.”

Though somewhat depressing from a personal/survivalist point of view it is true. To me the grand scale of time that makes geology incredibly fascinating also forces us to understand our own mortality. Added with the ever changing surface processes such as volcanoes, earthquakes, landslides, etc. my sense of indestructible dominance is compromised.

All of this reminds me of another quote, or series of quotes. This time from George Carlin.

“the planet has been through a lot worse than [humans]…it’s not going anywhere. We are.”

“…the planet probably sees [humans] as a mild threat, something to be dealt with, and I’m sure the planet will defend itself”

But this is not meant to be a downer. The very reasons we as a species are susceptible to Earth’s dynamic past are why people like me choose to study or better understand it. Big scary explosions are exciting. It’s why we keep going to the movies.

I am going to wrap up with one last quote from John Playfair after first comprehending the geologic time scale as described to him by James Hutton at Siccar Point, Scotland:

“the mind seemed to grow giddy by looking so far into the abyss of time”

*If you would like to read the rest of the Simon Winchester article where he discusses literary works, here is the link:
http://thebrowser.com/interviews/simon-winchester-on-volcanoes

*If you would like to watch the entire George Carlin bit, here is the link to that:
http://www.youtube.com/watch?v=EjmtSkl53h4

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