Geologic and kinematic constraints on Late Cretaceous to mid Eocene plate boundaries in the southwest Pacific

Kara J. Matthews*, Simon E. Williams*, Joanne M. Whittaker^, R. Dietmar Müller*, Maria Seton*, Geoffrey L. Clarke* 

*EarthByte Group, School of Geosciences, The University of Sydney, NSW 2006, Australia
^Institute for Marine and Antarctic Studies, University of Tasmania, TAS 7001, Australia

Email: kara.matthews@sydney.edu.au, 

CITATION
Matthews, K.J., Williams, S.E., Whittaker, J.M., Müller, R.D., Seton, M. and Clarke, G.L., 2015. Geologic and kinematic constraints on Late Cretaceous to mid Eocene plate boundaries in the southwest Pacific. Earth-Science Reviews, 140(0): 72-107.



We provide the rotations for our southwest Pacific kinematic model, along with coastline and continental block geometry files (in GPlates GPML format and ESRI Shapefile format), to enable the model to be visualised using the plate reconstruction software GPlates (Boyden et al., 2011). Rotations for the plate pairs in the adopted Antarctic plate circuit (Australia-East Antarctica, Lord Howe Rise-Australia, West Antarctica-East Antarctica, Pacific-West Antarctica) correspond to circuit 'AntC4' (Table 2 in the main text). We also provide rotations for the motion of East Antarctica relative to Africa (Cande et al., 2010; Bernard et al., 2005) to allow for easy testing of alternative absolute reference frames. These choices of East Antarctica-Africa rotations are from the Seton et al. (2012) global plate motion model. 

The model starts at 85 Ma and ends at 45 Ma, there are no plate motions before or after this time frame. We have chosen to compute rotations at 45, 52, 74 and 85 Ma, for the main plates in the Antarctic plate circuit, our arcs associated with the formation and closure of the South Loyalty Basin, and the motion of East Antarctica relative to Africa.  Also included in the rotation file is the kinematic model for the opening of the Tasman and Coral seas of Gaina et al. (1998) and Gaina et al. (1999), and motion of the Western and Eastern South Tasman Rise from Whittaker et al. (2013), which have all been taken from the global plate motion model of Seton et al. (2012).

We provide coastlines and continental block outlines for the region of interest. The continental blocks file (based on Seton et al., 2012) contains regions of continental crust, or regions of presumed continental crust. The blocks are rigid features, which is a simplification, particularly in locations such as the West Antarctic Rift System and Lord Howe Rise where there have been episodes of continental deformation during the time frame investigated in this study. We have defined a rigid boundary between the East and West Antarctica (Marie Byrd Land, including the Amundsen Terrane) continental blocks in the West Antarctic Rift System, which is an approximation. Coastlines/continental blocks from the Thurston Island, Antarctic Peninsula and Ronne Ice Shelf regions are not included.

The rotation file (.rot) is formatted for GPlates: 
Column 1: Moving plate ID
Column 2: Time (Ma)
Columns 3, 4, 5: Euler rotation pole (latitude, longitude, angle of rotation)
Column 6: Conjugate or "fixed" plate ID
Column 7: Comment (beginning with "!") usually providing a description of the plate pair and relevant publication reference
*Note: A line consisting of "999  0.0   0.0    0.0    0.0  999 !" is a comment line

When loading the files in GPlates 701 (Africa), or the plate ID for one of the plates in the southwest Pacific plate circuit must be specified as the anchored plate ID. To do this select 'Reconstruction' from the main navigation bar, and then select 'Specify Anchored Plate ID...' from the drop down menu.

Plate IDs for main blocks:
Africa 701
Australia 801
East Antarctica 802
West Antarctica 804
Lord Howe Rise 833
Pacific 901

NOTE: (updated Feb 2015)

We also provide a rotation file that adopts our preferred Australian plate circuit (Australia-East Antarctica, Lord Howe Rise-Australia, West Antarctica-Pacific, Pacific-fixed to-LHR), corresponding to circuit 'AusC2' (Table 4 in the main text). When loading this rotation file in GPlates make sure to turn off or unload the geometry file containing the Southwest Pacific arcs (Matthews_etal_southwest_Pacific_arcs.gpml -or- .shp) as this kinematic model assumes no subduction zone existed east of Australia during this time frame.


Files included in Supplementary material:
-Geometry files (GPlates GPML and ESRI Shapefile formats)-
Matthews_etal_southwest_Pacific_arcs.gpml (or .shp)
Matthews_etal_southwest_Pacific_coastlines.gpml (or .shp)
Matthews_etal_southwest_Pacific_continentalblocks.gpml (or .shp)

-Rotation files-
Matthews_etal_southwest_Pacific_rotations-Antarctic_circuit.rot
Matthews_etal_southwest_Pacific_rotations-Australian_circuit.rot




REFERENCES (from the readme file and rotation file)

Bernard, A., Munschy, M., Rotstein, Y. and Sauter, D., 2005. Refined spreading history at the Southwest Indian Ridge for the last 96 Ma, with the aid of satellite gravity data. Geophysical Journal International, 162(3): 765-778.

Boyden, J.A., Müller, R.D., Gurnis, M., Torsvik, T.H., Clark, J.A., Turner, M., Ivey-Law, H., Watson, R.J. and Cannon, J.S., 2011. Next-generation plate-tectonic reconstructions using GPlates. In: G.R. Keller and C. Baru (Editors), Geoinformatics: Cyberinfrastructure for the Solid Earth Sciences. Cambridge University Press.

Cande, S.C., Patriat, P. and Dyment, J., 2010. Motion between the Indian, Antarctic and African plates in the early Cenozoic. Geophysical Journal International, 183(1): 127-149.

Gaina, C., Müller, R.D., Royer, J.Y., Stock, J., Hardebeck, J. and Symonds, P., 1998. The tectonic history of the Tasman Sea: a puzzle with 13 pieces. Journal of Geophysical Research, 103(B6): 12413-12,433.

Gaina, C., Müller, R.D., Royer, J.-Y. and Symonds, P., 1999. Evolution of the Louisiade triple junction. Journal of Geophysical Research, 104(B6): 12927-12939.

Granot, R., Cande, S., Stock, J. and Damaske, D., 2013. Revised Eocene‐Oligocene kinematics for the West Antarctic rift system. Geophysical Research Letters: 1-6.

Larter, R.D., Cunningham, A.P., Barker, P.F., Gohl, K. and Nitsche, F.O., 2002. Tectonic evolution of the Pacific margin of Antarctica 1. Late Cretaceous tectonic reconstructions. Journal of Geophysical Research, 107(B12): 2345.

Seton, M., Müller, R.D., Zahirovic, S., Gaina, C., Torsvik, T., Shephard, G.E., Talsma, A., Gurnis, M., Turner, M. and Maus, S., 2012. Global continental and ocean basin reconstructions since 200Ma. Earth-Science Reviews, 113(3): 212-270.

Whittaker, J.M., Williams, S.E. and Müller, R.D., 2013. Revised tectonic evolution of the Eastern Indian Ocean. Geochemistry, Geophysics, Geosystems, 14(6): 1891-1909.