Wednesday, October 4, 2017

Geologic Mélange: A Mixed Bag of Lithologies

      A geologic mélange consists of a jumble of large blocks of varied types of rocks.  A mélange is a large-scale breccia (rock consisting of angular fragments cemented together).  It is a mappable body of rock characterized by a lack of continuous bedding and the inclusion of fragments of rock of all different sizes, contained in a fine-grained deformed matrix.




       Large-scale mélanges formed in active continental margins generally consist of altered oceanic crustal material and blocks of continental slope sediments in a sheared mudstone matrix.






       The mixing mechanisms in such settings may include tectonic shearing forces, ductile flow of a water-charged or deformable matrix (such as serpentinite), 







and sedimentary action (such as slumping or gravity-flow). 






     Some larger blocks of rock may be as much as 1 kilometer (0.62 mi) across. Smaller-scale localized mélanges may also occur in shear or fault zones, where coherent rock has been disrupted and mixed by shearing forces.




      For my money, mélange is an beautiful-sounding word for a jumbled mess of lithologies. Sorting out environmental conditions in a mélange is a geological puzzle with well over 1,000 pieces.

Happy sorting and solving all those puzzle pieces!
Steph 

Deer and Dear Maizie---Fall in the Rockies:












62 comments:

  1. Was this inspired by this week's NPR puzzle?

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    1. I thought so, funny how the whole thing starts with the first food, and ultimately circles to the second food.

      I suspect we have a lot of mélangeology (first time the word has ever been used, you're welcome) here, is your first photo from the California coast? And where's the second photo from? My thumbnail is the Marin Headlands, north end of the Golden Gate Bridge.

      Years ago I took an amateur geologist friend to Big Sur, and he went crazy with delight.

      We also have a lot of natural serpentine rock outcroppings, giving us a healthy dose of natural asbestos.

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    2. The first image is the Kuromi Mélange in Japan. The second image is from the California coast, I believe.

      Yeah, CA is a great place for mélanges, serpentinites, and slickensides, too. Smooth.

      Great new thumbnail, eco.

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    3. Actually the second photo isn't California, I've never seen that kind of formation here. And then I realized, it's the Gwna Melange on the SW tip of the Llyn Peninsula and Bardsey Sound, in
      Uwchmynydd, Pwllheli, Wales. I always like to stay at the Maes Carafanau a Phebyll Fferm Ty-Newydd Farm Camping and Caravan Site when I'm in the neighborhood.

      If you ask me nicely I'll tell you how I figured that out...

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    4. I tried "Search Google for this Image" which possibly pointed to CA but I wasn't sure about that.

      Is your method to have gone there, eco? Or, do tell otherwise!

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    5. You don't think it's my encyclopedic memory?

      Okay, maybe I'm not so smart, just lucky. I did a google image search, but instead of dropping the image in like I've always done, I copied the url from your page. And this was the result. The image appears on the first page, thankfully, because I'm too lazy to go to page 2. And somehow I followed the links to the image to find the right web page, and scrolled through his base page to find storms which lead to this page, where his trip is described about 3/4 of the way down.

      I'm just glad the Sunday Puzzle isn't in Welsh, we'd have many fine games of "Find the Vowel".

      So who won Jeopardy! tonight? Wait Wait, Don't Tell Me!

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    6. And for what it's worth, I think I have the exact spot. Much more fun than working on equipment plans.

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    7. Yeah, I didnt have enough patience to work through the first suggestion of CA. Glad you did, though.

      Our man, Austin, won again. No wild wagering tonight though, just Sherbet/bertGate.

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    8. OK, conspiracy theorists, try this one on: 8-time, $300K Jeopardy champ Austin Rogers' first game aired on September 26, right in the middle of the week in which Austin, Dustin, Justin was the (repeat) answer to Will Shortz's NPR Weekend Edition Sunday puzzle. Austin's a bartender in New York; Shortz, of course, is the puzzle editor of the New York Times. Might they have cross paths at some point? Might Austin have tipped Will off ahead of the airing of his streak?

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    9. Maybe so, jan. I also wonder if, a few days in, the Jeopardy folks threw him easier questions based on the books in the background of his video series (i.e., the Nelson Mandela final Jeopardy question when he had a book by that name on his bookshelf.)

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    10. Well, there goes my chance to take down Austin Rogers.

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    11. Not over here yet but I thought that might be the case.

      Too bad.

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    12. They had to have thrown those Tennessee questions to Scarlett from Tennessee, though.

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    13. Haven't seen it yet, just reacting to an AP wire story.

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    14. ^^^Dolly Parton questions.

      Austin looked happier than Scarlett. What a gracious loss. I will miss watching him.

      Alex looked none too happy about the Dick Tree.

      $411,000 is pretty sweet in only 12 wins.

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    15. Good thing I didn't check this blog until late, you guys are a bunch of spoilers for us West Coasters. Actually I got home late and only saw Final Jeopardy, so the Dick Tree issue flies past me.

      Austin seemed extraordinarily exuberant about losing. Something odd there.

      Interesting that Ken Jennings also lost to a woman, as I recall. No particular reason for saying that, though it seems like they have more men than women on the show, try as they might for balance.

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    16. The Dick Tree shares initials with DT.

      The whole shebang . The DT does him in.

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    17. I think doing Jeopardy! is exhausting, taping 5 shows a day. Perhaps Austin was both tired and itching to get on to the next big thing. Still, it was a fun run. . .

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    18. Thanks for the clarifying link, WW, it all makes sense now. This article purports to describe about how a week of episodes is filmed in one day, but it's more about Alex Trebek. I just wish he didn't do commercials for rip-off life insurance policies.

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    19. When asked what off-screen time is like with Alex, Austin said "There is no off-screen time with Alex."

      Yes, those insurance commercials are so annoying and such a rip-off.

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  2. The last image is Marshall's Beach in San Francisco. Know that one, eco?

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    1. Marshall's is beautiful, though a bit small (disappears at high tide) and a small bit of a challenge to get to. Until the mid 90's this was part of the Presidio military base. Its remoteness made it very popular with the nudist crowd, especially canoodling gay men. Not sure what the MP's thought of that, or maybe they took part? Now it is part of the Golden Gate National Recreation Area; access is easier with a trail and steps, and a more diverse crowd visits.

      We used to play volleyball on the adjoining Baker Beach (the nasty MP's would make us dump our beer), which is easily accessed, wider and hence more popular.

      I prefer the Marin side of the Golden Gate, a bit wilder and sunnier. Though the thumbnail is obviously not a beach.

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    2. Sounds like Marshall's Beach was quite the Melangërie. . .;-)

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    3. We hiked around the Presidio, Marshall's and Baker Beaches, and the bluffs in between, a couple of years ago with some nieces. Marshall's still appears to be bathing suits optional. Several not very well-preserved gun emplacements still around.

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    4. It is California, after all. Buffs below bluffs.

      California has an interesting take on history in general, I think in part because the (non-Hispanic white people's) history is relatively short. Any building over 50 years old is considered "potentially historic", but they let these older emplacements slowly decay. Maybe some antipathy towards military overreach? My thumbnail is from a gun emplacement that dates to the Civil War.

      But other places like the Bodie ghost town, are also allowed to decay as nature takes its course.

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    5. My railfan brother-in-law once detoured us to the semi-ghost town of Copperopolis, CA, enroute from Yosemite to Piedmont. I failed to see the attraction.

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    6. Indeed, not much in Copperopolis, but remote Bodie is a treat if you happen to be on the east side of the Sierras. My first time there was on a Super Bowl Sunday, 12" of snow on the ground, temps well below 0°, and howling winds. Had the whole place to myself except fresh mountain lion footprints and a park ranger ("Just knock if you have any questions"), who stayed huddled in his cabin listening to the game - 49'ers were playing.

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  3. Fall trek with Maizie to Meyer Ranch photos added above. Gorgeous day!

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    1. Deer photo reminded me of a trip I made with some clients to look at their site in the Sierra Foothills. Suddenly their terrier ran off into the bushes, and came back with .... Bambi's lower foreleg. Probably mauled by a mountain lion, the dog was very upset when its owners took away its prize.

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    2. The dog happily delivered the leg to its owners, was it trying to pass the buck?

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    3. Dog thought it was good to the bone ... still had fur, so there was something to hide.

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    4. Do you guys always pelt yourselves with these bad puns?

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    5. Welcome, sdb >>> as often as possible, by the skin of our teeth.

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    6. Oh, deer, yes. But don't take it to hart.

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    7. SDB, I'm sure you won't buck that trend and will rack up another pun.

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    8. All of you: Please stop your fawning. I see all your points.

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    9. I see, sdb. Have you changed your cell phone provider to Venizon?

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    10. I still have a landline, so you could say I'm bucking the trend. Maybe if I had more doe.

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    11. This is all reminding me of how much I sure do miss my dear old Aunt Luurz. Talk about a rack contour.

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    12. And were it a furry critter with a "mask," would that be a raccoonteur?

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    13. No, it would be and aunt wrap on your.

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  4. Caption for the first Meyer Ranch photo: Maizie the Deerstalker.
    "Some larger blocks of rock may be as much as 1 kilometer (0.62 mi) across" reminds me of how by brother Mike described my 1977 Plymouth Horizon: "a box of rocks"... and he's not even a geologist!
    Thanks for the In-laws clip, jan. Falk and Arkin, both wonderful.

    LegoWhoHasAlwaysConfusedMelangeWithBlancmange

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  5. This is an old story, but at least it would extinguish the fires. And those annoying football players who think they have rights.

    I suppose some music will calm the fear.

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    1. Yeah, slip sliding away is the perfect CA earthquake song. Thanks for the link to the article, eco.

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    1. Pardon me, I just need to vent. The charming Scarlett Sims, who unseated Austin Rogers, was herself unseated by a Navy lieutenant who last night won with just $1 after being in distant third place, when all three players blew a Final Jeopardy whose category should have been "Stupid Answers", but was instead, "Asian Geography": "It's the only country that borders both the Caspian Sea & the Persian Gulf." He picked Iraq. No wonder the Navy finds its patrol boats captured in Iranian waters!

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    2. Yeah, that was full-on a gimme for you, me, Austin, and many others but none of the 3 participants. I've only watched the endings on line since Thursday. Now $1 wins the game? Can't wait for TOC and November 6.

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    3. I've missed Jeopardy the past several days, I often only get home in time to see the Final. But that is pretty embarrassing.

      Instead of book-burning maybe we just "Cooked" the Books. Mostly I just wanted an excuse to listen to that again.

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    4. eco, great song any time of day.

      Have you heard about Cash Cab in NYC? See if you recognize anyone there.

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    5. That was cute, and funny, though a little weird when he addressed his mother as "mommy". I liked the comment about how many Jeopardy the guy could potentially win.

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    6. Yeah, that was weird.

      Great 20/20 hindsight comment, too ;-).

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  7. New post on "Happy Birthday Earth (at 9 a.m.): Birthday Cake Served Up on a New Plate" is now up. Happy 6021st Birthday Earth!

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