[GPlates-discuss] plotting relative plate velocities

Christoph v.Hagke christoph.vonhagke at emr.rwth-aachen.de
Tue Sep 20 16:52:17 AEST 2016


Hi Christian and Sabin,

Thanks much! This really helps. All best,

Christoph



Am 20.09.2016 um 05:22 schrieb Sabin Zahirovic:
>
> Hi Christoph and Christian,
>
> Thanks for looking into this issue, and thanks for bringing it up.
>
> Christoph, I found it a little difficult to reproduce exactly what you 
> were doing, but I think I got there. I’ve got a few papers now that 
> are associated with a specific plate reconstruction model, so 
> Zahirovic et al. itself is not specific enough for me to figure out. I 
> am assuming it’s our 2014 paper on Southeast Asia.
>
> I used the kinematics tool in GPlates with the following setup (and 
> loaded the 2014 rotation file):
>
> Under settings:
>
> (Make sure you click Apply, then Close).
>
> I get something like this, which is similar to the trends you observe:
>
> If I do the same, but load in our recent plate reconstructions (Muller 
> et al., 2016, AREPS – also attached), then I get something more 
> geodynamically reasonable:
>
> You can see the comparisons also in the CSV files that I attach. The 
> differences are due to the rotations of Arabia relative to Africa, but 
> more-so the rotations of Eurasia relative to North America, and then 
> how that links back up to the absolute reference frame. We did detect 
> that problem a while back, and we removed a few of the rotations. This 
> usually happens when you have magnetic anomaly identifications that 
> are very close temporally, which can introduce sudden changes in plate 
> motion that are not geodynamically feasible. You can explore that in 
> more detail in a paper by Iaffaldano et al. (2014) 
> <http://onlinelibrary.wiley.com/doi/10.1002/2014GC005309/abstract>.
>
> In our older models we have these rotations for Eurasia:
>
> 301 47.9   65.38  138.44  -10.96  101 !EUR-NAM Gaina et al. 2002
>
> 301 53.3   63.07  144.26  -12.82  101 !EUR-NAM Gaina et al. 2002
>
> 301 55.9   56.17  145.06  -13.24  101 !EUR-NAM Gaina et al. 2002
>
> 301 68.7   54.45  147.06  -15.86  101 !EUR-NAM Gaina et al. 2002
>
> In our new models, we have these rotations for Eurasia (you can see 
> the ~53 Ma rotation has been removed):
>
> 301 47.9   65.38  138.44  -10.96  101 !EUR-NAM @REF Gaina_++_2002 
> @DOI"10.1016/S0012-821X(02)00499-5" (21o)
>
> 301 55.9   56.17  145.06  -13.24  101 !EUR-NAM @REF Gaina_++_2002 
> @DOI"10.1016/S0012-821X(02)00499-5" (25y)
>
> 301 68.7   60.38  146.96  -16.33  101 !EUR-NAM @REF 
> Barnett-Moore_++_(in review)
>
> For Arabia, we had these rotations:
>
> 503  0.0    0.0    0.0    0.0  701 !ARB-AFR Arabia-Nubia (Africa)
>
> 503 10.9   26.1   23.1   -3.86  701 !ARB-AFR Royer et.al 1998
>
> 503 20.6   30.9   17.5   -6.32  701 !ARB-AFR Royer et.al 1998
>
> 503 600.0   30.9   17.5   -6.32  701 !ARB-AFR
>
> Now Arabia’s motions are:
>
> 503  0.0    0.0    0.0    0.0  709 !ARA-SOM Arabia-Somalia
>
> 503  2.6   23.67   22.21   -0.939  709 !ARA-SOM @REF Fournier_++_2010 
> @DOI"10.1029/2008JB006257", @CHRONID"C2An.1y"
>
> 503  3.6   21.28   28.5   -1.619  709 !ARA-SOM @REF Fournier_++_2010 
> @DOI"10.1029/2008JB006257", @CHRONID"C2An.3o"
>
> 503  6.0   25.46   25.41   -2.398  709 !ARA-SOM @REF Fournier_++_2010 
> @DOI"10.1029/2008JB006257", @CHRONID"C3An.1y"
>
> 503  8.8   22.56   27.71   -3.985  709 !ARA-SOM @REF Fournier_++_2010 
> @DOI"10.1029/2008JB006257", @CHRONIS"C4Ay"
>
> 503 11.0   23.88   26.66   -4.74  709 !ARA-SOM @REF Fournier_++_2010 
> @DOI"10.1029/2008JB006257", @CHRONID"C5n.2o"
>
> 503 16.0   25.85   25.4   -6.853  709 !ARA-SOM @REF Fournier_++_2010 
> @DOI"10.1029/2008JB006257", @CHRONID"C5Cn.1y"
>
> 503 17.5   26.1   22.98   -7.283  709 !ARA-SOM @REF Fournier_++_2010 
> @DOI"10.1029/2008JB006257", @CHRONID"C5Do"
>
> 503 19.7   26.46   21.66   -7.83  709 !ARA-SOM @REF Fournier_++_2010 
> @DOI"10.1029/2008JB006257", @CHRONID"C6no"
>
> 503 231.0   26.46   21.66   -7.83  709 !ARA-SOM
>
> So the take-home message is that you should be using the latest plate 
> reconstructions. The most recent model with evolving plate topologies 
> is the AREPS Muller et al. (2016) model:
>
> http://www.earthbyte.org/ocean-basin-evolution-and-global-scale-plate-reorganization-events-since-pangea-breakup/
>
> A more recent model with some changes in the India-Eurasia and eastern 
> Tethys region is here:
>
> http://www.sciencedirect.com/science/article/pii/S0012825216302872
>
> I recommend the AREPS model as it has the evolving plate topologies 
> bundled, while in the other one we only provide the resolved 
> topologies exported as GMT/SHP files. Hope that helps.
>
> Cheers,
>
> Sabin
>
> *-- *
>
> *DR SABIN ZAHIROVIC | *Postdoctoral Research Associate
>
> School of Geosciences | Faculty of Science
>
> **
>
> **
>
> *THE UNIVERSITY OF SYDNEY*
>
> Rm 403, Madsen Building F09 | The University of Sydney | NSW | 2006
>
> *M* +61 416 775 589 *P* +61 2 9351 3625
>
> *E sabin.zahirovic at sydney.edu.au 
> <mailto:sabin.zahirovic at sydney.edu.au>***| *W* 
> *http://www.earthbyte.org* <http://www.earthbyte.org/>*| R 
> http://www.researchgate.net/profile/Sabin_Zahirovic*
>
> *F https://www.facebook.com/earthbyte***|* T 
> https://twitter.com/EarthByteGroup*
>
> *Faculty contact for the Society of Exploration Geophysicists (SEG) - 
> Member # 283117*
>
> **
>
> Most recent publications:
>
> Zahirovic, S., Matthews, K.J., Flament, N., Müller, R.D., Hill, K.C., 
> Seton, M. and Gurnis, M., (In Press), Tectonic evolution and deep 
> mantle structure of the eastern Tethys since the latest Jurassic, 
> /Earth Science Reviews 
> <http://www.sciencedirect.com/science/article/pii/S0012825216302872>/, 
> doi: 10.1016/j.earscirev.2016.09.005.
>
> Zahirovic, S., N. Flament, R. D. Müller, M. Seton, and M. Gurnis (In 
> Press), Large fluctuations of shallow seas in low-lying Southeast Asia 
> driven by mantle flow, /Geochemistry, Geophysics, Geosystems/ 
> <https://www.researchgate.net/publication/306088667_Large_fluctuations_of_shallow_seas_in_low-lying_Southeast_Asia_driven_by_mantle_flow>/,/ doi: 
> 10.1002/2016GC006434.
>
> CRICOS 00026A
>
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>
> On 19/09/2016, 11:54 PM, "GPlates-discuss on behalf of 
> Christian.Heine at shell.com" 
> <gplates-discuss-bounces at mailman.sydney.edu.au on behalf of 
> Christian.Heine at shell.com> wrote:
>
>     Christoph,
>
>     > I used the Zahirovic et al. model to extract plate velocities. I 
> tried to
>
>     > create plots with relative plate movements, and followed the 
> instructions
>
>     > from the tutorial.
>
>     This 
> (https://docs.google.com/document/d/1xUHGu1N-nirc9t2srspdSOsmx0jrRsrBoJgWw5Ge0bI/pub) 
> one?
>
>     [snip]
>
>     > Here my first plot, it shows convergence of Arabia and Eurasia. 
> (It's
>
>     > based on an India-Eurasia-Convergence plot Sabin was kind enough to
>
>     > share, and which I could reproduce, too)
>
>     Attached my version which looks slightly similar but doesn't have 
> the spikes at 27/16 Ma. This is for a point close to Kuweit.
>
>     > Looks great, but has these two excursions at 27 & 16 Ma, which I 
> find
>
>     > geologically difficult. Is this an artifact? How would you deal 
> with it?
>
>     You haven't mentioned whether you use a single point or the 
> velocity domain points to achieve this. I think in the latter case, 
> what could happen (and lead to the spikes) is if a plate boundary 
> moves across your velocity domain point for a very short amount of 
> time and you hence pick up velocities from a separate plate there.
>
>     Depending on what you're trying to do it might be easier to 
> digitise your points as 'standard' features and then use them for 
> input for a new 'Calculated velocity fields' layer (simply add a new 
> layer in the layer mgr) instead of the velocity domain points.
>
>     > Second, I tried to do the same plot for Arabia and India. 
> Unfortunately
>
>     > sth went wrong here, and in the .xy export files it shows the 
> wrong plate
>
>     > IDs. I tried it several times, but don't get it to work. Any idea is
>
>     > appreciated. Thanks and cheers,
>
>     Could be the same issue as above. Using the kinematics tool I can 
> happily make vel magnitude vs time plots for ARA-IND. Try digitising a 
> point and export vels from there.
>
>     HTH,
>
>     Christian
>
>     --
>
>       Christian Heine, Ph.D.
>
>       Upstream - Opportunity Identification (UPX/N/OH)
>
>       Shell Intl. Exploration and Production B.V.
>
>       Carel van Bylandtlaan 5 | C05-01-B33
>
>       2596 HP Den Haag, The Netherlands
>
>
>
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-- 
Dr. Christoph von HAGKE
Assistant Professor

Institute of Structural Geology, Tectonics and Geomechanics
RWTH Aachen University, Lochnerstraße 4-20, 52056 Aachen, Germany

Ph.: +49 241 80 98443

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