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View Diary: Mars Rock Stuns NASA Scientists (162 comments)

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  •  I'm excited, but this is so complicated (41+ / 0-)

    that it's hard to explain to a general audience. Geologists are still hotly disputing the details of origins of rocks like 'Jake" on earth. Emily L did a great job of explaining most of it, but she missed the zinc discrepancy.

    I hope folks ask questions in the comments so I can clarify.

    look for my eSci diary series Thursday evening.

    by FishOutofWater on Sun Oct 14, 2012 at 07:36:48 AM PDT

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    •  oh, I can't give it even a try to dig (8+ / 0-)

      into the science part and ask questions ... the diaries like yours just bring up memories of times in my life, where I didn't shy away to try to understand the science part ...and was not yet ashamed of myself, because I had the feeling I could understand enough to ...get exited.  Days long bygone unfortunately.

      I admire your diaries, even if I can't follow and read them all. Please don't give it up to write them. I still have hopes I get back to them one day and start digging... :)

    •  Geology is hard (7+ / 0-)

      Okay, now that I'm done hating myself for that pun, it really is tricky. I kept hoping to see something about more microbial activity so i had something to say.

      In the end, all I have is a lame pun and a fascination slightly muddled from a level of excitement im not used to seeing in a story about geology.

      Still glad its here though! I just have nothing to say about it :P heh

      Then you came out all of a sudden and said, "You're Prism Indigo!" but I don't get it...

      by kamrom on Sun Oct 14, 2012 at 08:58:11 AM PDT

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    •  Excellent post!!! (6+ / 0-)

      And a great exposition of how science works: observations and the technology behind them, how they are used in the formation of hypotheses and how those are tested. Just great. I'm not a geologist, but as a physicist I understand the gist of it. One (maybe naive) question. The rock indicates "something that requires a dynamic, evolving geologic environment..". Aren't these igneous geophysical processes something we in general expect for (solid) planet formation? Under what conditions would plate tectonics not occur, and how would that depend say on the thermal conductivity of the interior and the rate of surface cooling?

      The truth of our faith becomes a matter of ridicule among the infidels if any Catholic, not gifted with the necessary scientific learning, presents as dogma what scientific scrutiny shows to be false. - Thomas Aquinas

      by oxley on Sun Oct 14, 2012 at 09:22:17 AM PDT

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      •  Maybe I'm OT here (1+ / 0-)
        Recommended by:
        Aunt Pat

        b/c my question might be more about the geophysical fluid dynamics which is not the main point. Except for the temperature and pressure part.

        The truth of our faith becomes a matter of ridicule among the infidels if any Catholic, not gifted with the necessary scientific learning, presents as dogma what scientific scrutiny shows to be false. - Thomas Aquinas

        by oxley on Sun Oct 14, 2012 at 09:41:34 AM PDT

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      •  What I recall is large-scale plate tectonics can (9+ / 0-)

        occur only on planets with rocky surfaces that have some degree of differentiation (crust-mantle). This may require some minimum size for a planet. Based on what we see of the inner planets, Mercury seems too small for plate tectonic processes to have been active. Venus seems to have (or have had) some type of plate tectonic activity, as does similar-size Earth. Mars is between Mercury and Venus-Earth in size and IIRC some had suggested that the alignment of the large volcanoes on Mars (Tharsis area) suggested that plate tectonics may have operated for a time and then stopped on Mars.

        Plate tectonics requires a solid crust underlaid by a plastic zone so that the plate can move. Subduction of plates drives the process as a denser plate sinks into the plastic zone. The speed of tectonic processes is controlled in part by the thickness of the solid crustal plates. Plates were probably much thinner and more mobile a few billion years ago on Earth.

        This is what I mostly recall reading some time back, and perhaps someone can identify things I have noted that are no longer thought to be correct.

        •  And, I believe, it also requires a planet with (3+ / 0-)
          Recommended by:
          oxley, Aunt Pat, FarWestGirl

          a heated core, not a cool core, which explains much of the dynamics.

          I read early on that the water on Mars may have gone the way of the Dodo because the core cooled relatively quickly, and this also changed the atmosphere.

          Hope I got that right!  Been a little while since I read that about Mars.

          202-224-3121 to Congress in D.C. USE it! You can tell how big a person is by what it takes to discourage them. "We're not perfect, but they're nuts."--Barney Frank 01/02/2012

          by cany on Sun Oct 14, 2012 at 01:00:57 PM PDT

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          •  A planet loses heat after it forms. With time the (4+ / 0-)

            plastic/fluid zone necessary for plate movement would also lose heat. At some point, that heat loss may cause that zone to get "thicker" and perhaps become essentially "solid." Then plate movement would cease.

            Planets can generate heat as well - mainly through decay of radioactive elements. A substantial amount of the heat flowing from the Earth at this time has this origin. I once had the impression that the original heat of the Earth had been lost and all the present heat was radiogenic, but I believe I recently read that this is not correct and that perhaps a third of the heat coming from Earth at this time is original heat.

            I'm not sure about core temperatures directly affecting the surface water on Mars, but there certainly are lots of evidences of flowing water once having been there. At the current temperatures/pressures, liquid water should not be stable.

            •  That's interesting. (2+ / 0-)
              Recommended by:
              Aunt Pat, FishOutofWater

              So again, how does the planet cool, and how does that lead to the layering crust-over plastic/fluid zone? You would have convection in the viscoelastic (I guess) zone beneath the crust, and heat transport through episodic events through the crust? Conductive heat transport would be slow, but ongoing. I love this stuff...wish I had more time to think and read up about it.

              The truth of our faith becomes a matter of ridicule among the infidels if any Catholic, not gifted with the necessary scientific learning, presents as dogma what scientific scrutiny shows to be false. - Thomas Aquinas

              by oxley on Sun Oct 14, 2012 at 04:29:09 PM PDT

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              •  The initial heat came from impacts of material (0+ / 0-)

                that built the planet in the very early stages. At some point the heat became high enough that partial melting occurred and materials separated by density. For Earth this initial segregation formed the iron core and the less dense mantle. The crust formed by segregation of rocky mantle materials.

                The cooling of Earth is through conduction of heat from the solid Earth to the ocean and atmosphere. Rock is a poor conductor of heat, so the cooling process took vast lengths of time. The rock closest to the surface loses heat most quickly, so a solid shell forms over a more fluid interior and you have the beginning of plate motion. Many of the rocks of the Canadian Shield seem to have formed when the crust was thin and plate movement was faster than at present.

                Heat is also lost through convection near plate boundaries, but this convection is no longer thought to drive plate tectonics.

                Cooling can also occur as molten rock physically moves up and onto the surface of Earth.

            •  From what I understand, as a geologist and a (0+ / 0-)

              scientific generalist, the vast bulk of earth's internal heat has radioactive decay as the source. I remember reading that Lord Kelvin, in the late 1800s, calculated the earth as approximately 100 million years old based on the state of coolness, without the benefit of knowing about radoactvive decay and the attendant heat.

              Of course decay has spent much of the young earth's radioactive energy, and the tectonic processes have no doubt diminished because of it.

              In politics you've got to learn that overnight chicken shit can turn to chicken salad - LBJ

              by huntergeo on Sun Oct 14, 2012 at 06:12:38 PM PDT

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              •  Sorry I've been out playing a gig, and just got (0+ / 0-)

                back. I will try to track down the article I referenced about heat sources. I think I can find it tomorrow. I will send you a reference through KOS mail when I find it.

          •  Yeah, so that's what I'm (2+ / 0-)
            Recommended by:
            FishOutofWater, Aunt Pat

            wondering about. Heat sources driving things like convection and how that heat escapes through the surface.

            The truth of our faith becomes a matter of ridicule among the infidels if any Catholic, not gifted with the necessary scientific learning, presents as dogma what scientific scrutiny shows to be false. - Thomas Aquinas

            by oxley on Sun Oct 14, 2012 at 04:20:05 PM PDT

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    •  You did a great job. I haven't been around (4+ / 0-)

      mineralogy or petrology for a while, but this was absolutely fascinating and now I want to read more.

      Thus why I went to school in geology:)

      202-224-3121 to Congress in D.C. USE it! You can tell how big a person is by what it takes to discourage them. "We're not perfect, but they're nuts."--Barney Frank 01/02/2012

      by cany on Sun Oct 14, 2012 at 12:58:26 PM PDT

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    •  so here's a question: how does that geometry form (1+ / 0-)
      Recommended by:
      ozsea1

      .... in igneous rock?

      How do you get that kind of formation in rock that is cooling from a molten state?   What I would expect is for that type of rock to have smooth, rounded edges, or an indistinct lumpy shape perhaps with sharp edges where it broke off from a larger piece.  

      But what we see there has a geometry similar to that of crystals: hard straight edges and symmetry along at least one axis (in this case vertical).   The edges aren't perfectly straight and the symmetry isn't perfect either, but clearly both are not accidents: they have to be the result of some physical process that isn't purely random such as breakage from a larger object.

      What's the process, and how common are similar rocks with similarly geometric features on Earth?

      (And FYI in case anyone's wondering: no, this is not about "crystal woo."  My sarcastic term for the New Agers' fascination with crystals is "new-age pet rocks."  There are strong rational reasons to be interested in the geometry of rock formations found on Mars.  And my interest in Martian geology is ultimately focused on the goal of colonizing Mars, and seeking out materials that can be used in the construction of extensive Martian colonies.)

      "Minus two votes for the Republican" equals "plus one vote for the Democrat." Arithmetic doesn't care about their feelings either!

      by G2geek on Sun Oct 14, 2012 at 06:51:57 PM PDT

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      •  Hexagonal cooling fractures. Devils Postpile. (0+ / 0-)

        Natural processes such as cooling fractures can give a rock  geometric shapes. Near surface volcanic rocks frequently form vertical hexagonal columns as they cool and contract. The there are mudcracks which are not quite so pretty.

        look for my eSci diary series Thursday evening.

        by FishOutofWater on Mon Oct 15, 2012 at 04:32:08 AM PDT

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