2012-03-22

Ideas on open questions in Earth Science?

[PD: The result of this initiative is in this later post]

Searching for Unknowns consumes most of our research time and also makes the bulk of our research motivation. Wouldn't it be good to share the biggest open questions in our respective disciplines? 

I'm working on a list of challenging and sound geoscientific questions being researched today. Geoscience is here taken in the wide sense, including climate, hydrology, planetary science, ecology, geology, geophysics, etc.
I'm thinking of specific problems that are well established from a scientific point of view and that have an impact on at least a couple of subdisciplines. Examples would be: "What caused the Permian extinction?" or "What drives magnetic polarity reversals?" or "How much of the current climate change is anthropogenic?". But a bit more of elaboration and a key reference would be desirable.
I will try to summarize the compiled ideas in a later entry in this blog, but key references discussing each subject are welcome. I'm looking forward for suggestions or feedback, either as comments to this post (below) or at @danigeos on Twitter.

Update:
Alexandra Witze shares links (in a comment below) to the following relevant documents: 1, 2. Some of the questions summarized there will be useful as a general frame to what i aim at (they are big trans-scientific goals). But I would like to find the top key questions at a more detailed level, more specific, even if of interest only to a minority of subfields within Earth Sciences. Open problems that most assistants to the AGU, EGU, GSA or INQUA meetings could be curious about even if only a small percentage could really judge critically.

Update 2:
A reference to a key paper on the problem proposed will make every contribution much more valuable!

Update 3:
The result of this initiative is in this later post:

27 comments:

  1. not sure if this is the type of question you are looking for, but this is what motivates my research:

    How do rates of erosion (sediment production) influence patterns of preserved sediment deposition?

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    1. It is indeed. Are you working on delta fans? You mean plan view patterns? Is there some review paper that can introduce the problem?

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    2. Preserved 3D patterns -- so, yeah, plan view AND cross sectional. Additionally, not just patterns in space, but also in time.

      Researchers at Imperial College London are doing some interesting stuff using diffusion theory to test pretty similar question: http://www.nature.com/ngeo/journal/v4/n4/full/ngeo1087.html

      I've been involved in some research using cosmogenic-derived erosion rates compared to deposition rates: http://geology.gsapubs.org/content/early/2011/05/19/G31801.1.abstract

      But, I don't know of a review paper off the top of my head.

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  2. Can a simple model - based on few variables that encompass most of the variability - that allows paleoecological/climatic reconstructions based of paleo-river forms/patterns be developed?

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    1. Thanks! I reformulated this into "Can we reconstruct past ecology or climate from paleo-river patterns/forms?" in Twitter, tell me if i missed something. I guess you think of a quantitative link between both, as i do.

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    2. Yes, I think it is a good synthesis. We need something quantitative. But even if only qualitative, it would be a lot already .
      There is a nice paper (Hartley AJ, Weissmann GS, Nichols GJ, Warwick GL. 2010. Large Distributive Fluvial Systems: Characteristics, Distribution, and Controls on Development. Journal of Sedimentary Research 80: 167-183.) that describes Distributary Fluvial Systems DFS. Although climate is clearly a factor in controlling the final form, same forms occurs in very different settings (i.e. large DFSs with sinuous planforms can occur in both dry and wet settings).

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  3. This comment has been removed by the author.

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  4. What are the rates of magma accumulation and what mechanism(s) make magmas eruptible?

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    1. Thanks Erik,
      Accumulation where? at the chamber? Are you talking about what activates an eruption? Any review paper on the subject that displays the present controversy/unknowns?

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  5. One that comes to my head is the jelly sandwich vs. creme brulée issue for the rheological behaviour of the lithosphere. Is the lower crust ductile? Is strength concentrated at the uppermost mantle? Or just the other way around?

    Maybe not the best paper for this purpose, but this and another good open question are introduced here in 1 page:
    Westaway and Bridgland
    Quaternary erosion-induced isostatic rebound in the western Alps: Geology, January 2008, v. 36, p. e168, doi:10.1130/G24664C.1

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  6. And another one i must contribute is the issue about finding field evidence for the computer-predicted effects of erosion/climate on the patterns of tectonic deformation. A good introduction is Whipple, 2009, nature Geosc.

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  7. Alexandra Witze23 March, 2012 21:59

    Also see the related 2008 National Academy of Sciences report:
    http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=12161
    http://www.nap.edu/catalog.php?record_id=12161

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    1. These are Great Alexandra. Somewhat general, i was thinking of more specific scientific problems, addressed to other researchers. But these docs will help me to frame the whole thing. I looked for something like that but failed to find it, thanks.

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    2. another good NAS report is the 'Landscapes on the Edge' document from 2009 that proposes/discusses the big questions in Earth surface processes (geomorphology, landscape evolution, sedimentology, stratigraphy, tectonic-climate-surface feedbacks, etc.).

      http://dels.nas.edu/Report/Landscapes-Edge-Horizons/12700

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  8. Has the geomagnetic field always been largely dipolar, or could it have been more asymmetric in the past?

    What causes superchrons? Something internal to the core, or induced externally by the mantle/subducting slabs?

    How does short-term deformation (elastic strain measured by GPS) link with long-term deformation (displacement on faults)?

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    1. Chris R- Related to you last suggestion is:

      if present-day GPS displacements compare well with geologically constrained kinematic models (middle ocean ridge azimuths, magnetic alinements and transform faults, etc.). Apparently, there is some significant discrepancies [Calais et al., EPSL 2003], but I haven't read in detail last models [DeMets MORVEL model, http://geoscience.wisc.edu/~chuck/MORVEL/index.html], they should give some hints about it. Perhaps, I am interested in the particular circuit North America - Nubia - Eurasia.

      if plate interiors are really moving in steady-state linear motion (how rigid?), or it is just a matter of geodetic data precision/observation scales. Some encouraging/controversial readings might be Davis et al., (2005) doi:10.1038/nature04781, and Wernicke and Davis, (2010) doi:10.1785/gssrl.81.5.694. Conversely, ~30 years of geodetic observations in New Madrid area seem to indicate no significant strain.

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    2. nice Chris. The first ones deserve a chapter!

      The last one links with the type of question Christoph proposes below and with Pablo's (thanks Pablo for the references).
      I would generalize this question: How does the long term deformation derived from paleomagnetism link quantitatively to the present-day GPS motion and to the neotectonic patterns of crustal deformation? Can we learn from regional structure of the crust/lithosphere from that link (or viceversa)? How/when does deformation propagate from the plate boundaries into plate interiors? I'll dig good refs for these questions.

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  9. Another question/issue that is of great interest to Earth-surface researchers has to do with to what degree external forcings such as perturbations in tectonics and climate are recorded in the stratigraphic record. Jerolmack & Paola (2010) argue that the dynamics intrinsic to the sediment transport system can (but not always) be 'noisy' enough to drown out any signal of an external forcing.

    Jerolmack, D.J., and Paola, C., 2010, Shredding of environmental signals by sediment transport: Geophysical Research Letters, v. 37, L19401, doi:10.1029/2010GL044638.

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    1. This is a must, I agree, and related to the one you mentioned first. Maybe they could go together in the list.

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  10. What role do subsurface microbes play in the history of earth in regards to soil formation and their impact on climate?

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  11. What does the plate boundary between Spain and Africa really look like?

    What triggers earthquakes?

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  12. My top one in geology would be the geomagnetic polarity reversal question... though I'd never thought about Chris' point before. Man, I hope I live to see a reversal! I know the chances are rather slim...

    Here's one from petroleum geoscience: how can we get hydrogen out of petroleum deposits, leaving behind the carbon? (Today, microbes are the most promising lead, e.g. Steve Larter's work on bitumen at the University of Calgary).

    My more poetic side wonders this: to what extent is Gaia a useful model of the earth? This gets at a more fundamental problem: how can we model the earth as a complex system of systems? I think we're rather bad at this today: we tend to seek overly 'compact' explanations. Just my opinion.

    If you can dig up enough references to avoid immediate deletion, it might be fun to build a page in Wikipedia.

    I tried making a list like this for exploration geophysics once; you can see it in Google Moderator (inexplicably still alive!). Only the first of them is really relevant to geology in general: how can we represent subsurface uncertainty and make numerical and conceptual error and uncertainty part of our modelling methods?

    Great question, thanks for asking!

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    1. good question the hidrogen one! Any ref? I never heard of that yet.

      A wikipedia list could easily fall in "self-research" premises, and be (rightfully) erased or tagged. Would be nice to upload the final results there, though (if proper key references are contributed). What else could we use for public edition?

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  13. A question that's close to home for me is, "What are the causes of and contributing factors to the development of Large Igneous Provinces such as the Columbia River Basalts." It's a difficult question to address in large part because of the very nature of these eruptive events burying the evidence beneath hundreds of meters of basalts.
    It gets to very interesting questions here in the Pacific Northwest about the nature of subduction in this region (and others) and the extended history & behavior of the subducting slab.

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    1. I saw crossed those basalts 2 weeks ago, Michael. Impressive. They put me lots of questions indeed, but i think these are more related to my ignorance than to open geoscientific problems (how far do these lavas flow, and ho flat do they fill the landscape? Is there a present analogue for LIP formation?)

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  14. Still working on this. I got these recently by mail:

    What caused the largest carbon isotope changes in Earth? [Nat.Geo review]
    Were there ever lakes on Mars? And large outburst floods similar to those on Earth?
    Was there ever a snow-ball Earth?
    What caused the Quaternary extinction? Human expansion? Climate Change? And more specifically: what caused the large fauna extinction 13,000 yr ago? A result of the Younger Dryas climatic event? Extraterrestrial impact? Agassiz megaflood?
    How much of the present climate change is anthropogenic? How will growing emissions from a growing global population impact on climate?
    What were the causes of the K-T extinction? What about the Permian-Triassic or the Late-Triassic extinctions? [recent papers: ex1, ex2]

    (any feedback?)

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  15. Ocean and Earth Science Degrees at the University of Southampton has an excellent reputation in its field. We are known for our relaxed, friendly and informal atmosphere, which affords degree students a stimulating environment in which to learn and acquire essential scientific and key work skills. Our staff provide essential contributions to current debates about geological, geophysical, oceanographic and climate change issues, and it is our ability to offer innovative courses, delivered by leading experts in the field, that characterise our degree programmes.

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