Orbit-driven climate cycles exposed in sedimentary layers, "Quasi-Periodic Bedding in the Sedimentary Rock Record of Mars" |
Orbit-driven climate cycles exposed in sedimentary layers, "Quasi-Periodic Bedding in the Sedimentary Rock Record of Mars" |
Dec 6 2008, 10:16 PM
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Member Group: Members Posts: 646 Joined: 23-December 05 From: Forest of Dean Member No.: 617 |
Universe Today article on a new Science paper, "Quasi-Periodic Bedding in the Sedimentary Rock Record of Mars" (abstract. ) (UT just happened to be the first write-up I came across; there's plenty of coverage elsewhere.)
QUOTE "One of the fun things about this project for me is that we were able to use techniques on Mars that are the bread and butter of studies of stratigraphy on Earth," says Aharonson. "We substituted a high-resolution camera in orbit around Mars and stereo processing for a geologist's Brunton Compass and mapboard, and were able to derive the same quantitative information on the same scale. This enabled conclusions that have qualitative meaning similar to those we chase on Earth." It would be curious if the process that caused this terraced / stepped terrain would only show up in one location; are there any similar landforms? ISTR seeing many HiRISE images of layered terrain where the layers appeared, to my lay eyes, to be superficially similar, but I'm no geologist. How ubiquitous an effect is this in layered sedimentary rocks? Informed comment gratefully received -------------------- --
Viva software libre! |
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Dec 6 2008, 11:29 PM
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Member Group: Members Posts: 276 Joined: 11-December 07 From: Dar es Salaam, Tanzania Member No.: 3978 |
This discovery is actually quite important and I'm glad someone has started a thread about it. The formation and structure are due to martian milankovitch cycles and seem to be similar to the layers being formed at the poles. Basically one could say that this supports the hypothesis that ice used to cover the the temperate & equitorial regions of Mars.
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Dec 6 2008, 11:36 PM
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Member Group: Members Posts: 276 Joined: 11-December 07 From: Dar es Salaam, Tanzania Member No.: 3978 |
Evidently the discovery is also renewing debates on similar processes taking place on Earth. Here we have mostly 5:1 layers due to the the stabilising effect of the moon. The 10:1 layers on Mars are because the planet is free to wobble by a larger degree.
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Dec 7 2008, 06:40 AM
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#4
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Senior Member Group: Members Posts: 2228 Joined: 1-December 04 From: Marble Falls, Texas, USA Member No.: 116 |
This is one of the most interesting things I've read about in months. It would be nice if someone could find the HiRise stereo-pair that was described, and make some full resolution anaglyphs. This link to a Spaceflight Now article was passed to me via IRC.
-------------------- ...Tom
I'm not a Space Fan, I'm a Space Exploration Enthusiast. |
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Dec 7 2008, 11:39 AM
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#5
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Member Group: Members Posts: 153 Joined: 8-February 04 From: Phoenix, AZ USA Member No.: 9 |
This branch of geosciences is called cyclostratigraphy. Although cycles of sedimentation related to lunar, seasonal, and sunspot cycles had long been recognized, stable isotope analyses of fossil marine critters and sediments lead to the development of our current understanding of the relationships between incoming solar radiation (insolation) and the planetary orbital parameters of eccentricity, precession, and obliquity. The orbital-induced insolation effects are called Milankovitch cycles, after the Serbian mathematician and engineer Milutin Milanković who first quantitatively elucidated them. On earth, the most dramatic connection between orbitally-modulated insolation, climate, and sedimentary processes is the control of the growth and decay of continental ice sheets and the resulting sea level changes (as much as 100's m), the "pacemaker" of the Ice Ages. Of course, many more connections and teleconnections have been documented (strength of monsoons, ENSO cycles, etc.), thus the emergence of this branch of stratigraphy and related branches of geochemistry and paleoclimatology.
On modern (and geologically recent) Mars, it seems that orbitally-modulated insolation changes also must control the distribution and phase of volatiles on the surface and in the near-surface environments. As, on earth, other related climatic affects, including atmospheric circulation patterns, also vary in this beat-like fashion. We are just starting to glimpse the large-scale (here visible from orbit) physical stratigraphic evidence of these cycles. Regional and outcrop-scale mapping, along with facies and geochemical analyses will tell us much more... -------------------- Tim Demko
BioLink site |
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Dec 7 2008, 01:02 PM
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#6
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Member Group: Members Posts: 646 Joined: 23-December 05 From: Forest of Dean Member No.: 617 |
CosmicRocker - the "supplementary data" (PDF) includes this table, plus the layer location and thickness data:
CODE Crater Name Location Left Image Right Image ------------------------------------------------------------------------------------------ Becquerel 22◦N,352◦E PSP 001546_2015 PSP 001955_2015 Crommelin 5◦N,350◦E PSP 003432_1850 PSP 005766_1850 Unnamed 8◦N,353◦E PSP 002733_1880 PSP 002878_1880 Unnamed 8◦N,359◦E PSP 001902_1890 PSP 002047_1890 Table S1: HiRISE images used for stereo analysis at each location in Arabia Terra. Becquerel: http://hirise.lpl.arizona.edu/PSP_001546_2015 ; http://hirise.lpl.arizona.edu/PSP_001955_2015 Crommelin: http://hirise.lpl.arizona.edu/PSP_003432_1850 ; http://hirise.lpl.arizona.edu/PSP_005766_1850 Unnamed 1: http://hirise.lpl.arizona.edu/PSP_002733_1880 ; http://hirise.lpl.arizona.edu/PSP_002878_1880 Unnamed 2: http://hirise.lpl.arizona.edu/PSP_001902_1890 ; http://hirise.lpl.arizona.edu/PSP_002047_1890 -------------------- --
Viva software libre! |
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Dec 8 2008, 12:34 AM
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Senior Member Group: Members Posts: 2228 Joined: 1-December 04 From: Marble Falls, Texas, USA Member No.: 116 |
Thanks. The images are amazing, but while at the HiRISE site I noticed a message that said "3D coming soon." I think I'll wait for the HiRISE versions. They say they will be releasing hundreds of anaglyphs next week.
Oh, heck. I'm sure they won't mind if I post one or two ahead of time. Here is one from Becquerel at 1/16th scale. -------------------- ...Tom
I'm not a Space Fan, I'm a Space Exploration Enthusiast. |
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Dec 8 2008, 05:56 AM
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Senior Member Group: Members Posts: 2228 Joined: 1-December 04 From: Marble Falls, Texas, USA Member No.: 116 |
Here is another from Becquerel at 1/4th scale. It would be really nice if we could view anaglyphs in IAS Viewer.
tdemko: Thanks for that pacemaker link. You have got to imagine that this kind of research will play an important role in determining how our climate might be changing. -------------------- ...Tom
I'm not a Space Fan, I'm a Space Exploration Enthusiast. |
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Dec 8 2008, 07:41 PM
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Member Group: Members Posts: 646 Joined: 23-December 05 From: Forest of Dean Member No.: 617 |
Wow, those are great, thanks CR! What a happy coincidence that science and eye-candy turn up together. (Stepping gingerly around non-UMSF topics)... any idea what sort of vertical relief we're looking here? How tall is that spectacular spire half-way down the right-hand side of your second anaglyph, I wonder?
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Viva software libre! |
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Dec 8 2008, 10:41 PM
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Member Group: Members Posts: 104 Joined: 1-June 08 Member No.: 4172 |
The HiRISE website has an amazing DEM flyover of Becquerel available.
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Dec 10 2008, 04:00 AM
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Senior Member Group: Members Posts: 2228 Joined: 1-December 04 From: Marble Falls, Texas, USA Member No.: 116 |
That flyover was outstanding.
The HiRISE site has published a gallery of 362 anaglyphs of Mars' surface. They have full resolution JPEG2000 images and lower res PNGs. Best of all, like the regular imagery these can be viewed with IAS viewer. Here's the direct link to Becquerel anaglyph. -------------------- ...Tom
I'm not a Space Fan, I'm a Space Exploration Enthusiast. |
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Feb 1 2009, 07:31 PM
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Junior Member Group: Members Posts: 76 Joined: 4-June 07 From: United Kingdom Member No.: 2288 |
So, if I've grasped this correctly, every layer we see in those images is a warm to ice age swing happening over ten's of thousands of years ?
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Feb 1 2009, 09:37 PM
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Member Group: Members Posts: 688 Joined: 20-April 05 From: Sweden Member No.: 273 |
So, if I've grasped this correctly, every layer we see in those images is a warm to ice age swing happening over ten's of thousands of years ? Essentially yes, and as a matter of fact the same thing can be seen here on Earth, for example in Pleistocene Loess beds in Central Europe and Northern China, or Triassic lake sediments in New Jersey. However Earth is a much more dynamic planet than Mars, so it is very rare to find very long sequences or such beautiful exposures. |
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Feb 2 2009, 01:47 AM
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Member Group: Members Posts: 610 Joined: 23-February 07 From: Occasionally in Columbia, MD Member No.: 1764 |
......The orbital-induced insolation effects are called Milankovitch cycles, after the Serbian mathematician and engineer Milutin Milanković who first quantitatively elucidated them. Err, a better term is Croll-Milankovic cycles. The Scot, James Croll, really figured the whole thing out earlier (he studied the boulder clays and other geological evidence for glaciation, calculated how much heat the gulf stream transports and thus how much colder northern europe would be without it, and estimated the climatic effect of orbit/spin changes.). He laid out the big picture. Milankovic just redid the mathematics a little better..... |
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