Introduction to plate tectonics with GPlates

Ádám T. Kocsis

System Erde III - 2023-05-19

About

  • Akademischer Rat at the Paleontology (Master’s)
  • Work with paleoecological data, spatiotemporal patterns of diveristy
  • My German is not so good yet - Need for German slides/material?

Topics

1. Plate tectonics background

  • Repeat basic concepts
  • 1 lecture (30-40 minutes)

2. Introduction to GPlates (hands-on)

  • 4 lectures (today)

3. Assignment

GPlates

  • Need a computer with Win, Mac or GNU/Linux
  • We will install GPlates together
  • Exercise files on exercise webpage

Assignment

  • Practical exercise with GPlates
  • Short report (max. 3 A4 pages)
  • Assignment can be written in German
  • Due until the end of the lecture period (July 21) - necessary to pass the course


Schedule

Date Length Topic
May 11 Thursday (2h) Introduction/Starting with GPlates
May 17 Wednesday (1h) GPlates: rotations
May 18 Thursday Public Holiday
May 24 Wednesday (1h) Raster data and single points
May 25 Thursday (1h-2h) ???

History

Continents - Tectonic plates

The continent outlines seem to match

  • Jigsaw puzzle
  • (Ortelius 1596): Thesaurus Geographicus
  • Lilienthal, Humboldt, Snider-Pellegrinii, Kious etc.


(Snider-Pellegrini 1858)

Alfred Wegener (1880-1930)

  • 1912, Pangea
  • Die Entstehung der Kontinente (Wegener 1912)
  • Not fully accepted until 1970s

Evidence: Biogeography

from This Dynamic Earth (Kious and Tilling 1996)

Alternatives? Land-bridge…

Alternatives? The expanding Earth

Plate tectonics is most likely

  • No evidence for expansion/contraction
  • Subduction!

The Evidence

Plate margin types

Spreading

Pillow basalts at the Juan da Fuca ridge (NOAA-OE)

Mass balance: subduction and spreading

Evidence for subduction

The Tonga trench - Seismic tomography image

The plates actually move

Movement vectors of larger plates

Plates move above a hotspot

Plates move above a hotspot

(Torsvik et al. 2019)

GPS Measurements

Geomagnetism

Geomagnetism

Earth’s field is a dipole with ~11.5° to rotation axis.

Geomagnetism

Heterogeneity, declination

Geomagnetism

Inclination

Geomagnetism

Current inclination ~ latitude

Geomagnetism - Movement of poles

Yes, but not that much.

Paleomagnetism

  • Natural remanent magnetization
  • Conserved fossil magnetic field
  • Fe-Ti oxide minerals

Measurement? Magnetometer

A cryogenic magnetometer

Apparent polar wander

Current

With Atlantic closed

Reversals

(Glatzmaiers and Roberts 1995)

Paleomagnetic stripes

Conceptual figure

In reality

Radiometric dating

Oceanic lithospere ages

Event sequence: dating of anorogenic and orogenic rocks

Evolution of the Afar triple junction (Mège et al. 2016)

Records of Past subduction

Subduction of North American plate (Perkins 2019)

Paleobiogeography (faunal similarity)

Jurassic Ammonites in the terranes of Cordilleras (Smith and Tipper 1986)

Paleoenvironmental reconstruction

Major phases

  1. Tectonic model
  2. Local environment
  3. Topography
  4. GLobal Climatic Models

(Penn et al. 2018)

1. Tectonic model

Needs:

  • Current plate polygons
  • Rotation files

Outputs:

  • Past position of plates and present-day coordinates

2. Local environment

Needs

  • Lithofacies data
  • Fossils

Outputs:

  • Distribution of sedimentary environments

(Scotese 2016)

3. Topography reconstructions

3. Topography reconstructions

Needs:

  • Tectonic reconstruction
  • Environment distribution
  • Present-day topography
  • Knowledge of events

Outputs:

  • Topography raster

4. Climatic model

Needs

  • Topography
  • Physico-chemical parameters
  • A mechanistic model

Output

  • hundreds of raster variables

General Circulation Model: Phyisical focus
Earth System Model: Extra: Chemical reservoirs

4. Climatic model

Ocean surface temperature in the Cretaceous (Valdes, Scotese, and Lunt 2021)

https://climatearchive.org

General Circulation Model: Phyisical focus
Earth System Model: Extra: Chemical reservoirs

Implementing the tectonic reconstruction

GPlates

Developed from 2006 originally by Prof. Dietmar Müller (University of Sydney) (Müller et al. 2018)

GPlates

(Müller et al. 2018)

About GPlates

  • Free, open-source (GPLv2)
  • International development (U. Sydney, CalTech)
  • Desktop application
  • Python libraries (pyGPlates, gplately)
  • GPlates Web Service

Features

  • Basic GIS: vector and raster data manipulation
  • Manipulation of plate tectonic reconstructions (Basic GIS)
  • Plate motions, paleomagnetic data
  • Deep, mantle structures

Most important basic utility

  • Paleocoordinate rotations

Let’s take a look!

https://gplates.org

References

Glatzmaiers, Gary A., and Paul H. Roberts. 1995. “A Three-Dimensional Self-Consistent Computer Simulation of a Geomagnetic Field Reversal.” Nature 377 (6546): 203–9. https://doi.org/10.1038/377203a0.
Kious, W. Jacquelyne, and Robert I. Tilling. 1996. This Dynamic Earth: The Story of Plate Tectonics. DIANE Publishing.
Mège, D., P. Purcell, A. Bézos, F. Jourdan, and C. La. 2016. “A Major Dyke Swarm in the Ogaden Region South of Afar and the Early Evolution of the Afar Triple Junction.” Geological Society, London, Special Publications 420 (1): 221–48. https://doi.org/10.1144/SP420.7.
Müller, R. Dietmar, John Cannon, Xiaodong Qin, Robin J. Watson, Michael Gurnis, Simon Williams, Tobias Pfaffelmoser, Maria Seton, Samuel H. J. Russell, and Sabin Zahirovic. 2018. “GPlates: Building a Virtual Earth Through Deep Time.” Geochemistry, Geophysics, Geosystems 19 (7): 2243–61. https://doi.org/10.1029/2018GC007584.
Ortelius, Abraham. 1596. Thesaurus Geographicus.
Penn, Justin L., Curtis Deutsch, Jonathan L. Payne, and Erik A. Sperling. 2018. “Temperature-Dependent Hypoxia Explains Biogeography and Severity of End-Permian Marine Mass Extinction.” Science 362 (6419): eaat1327. https://doi.org/10.1126/science.aat1327.
Perkins, Sid. 2019. “Seismic Tomography Uses Earthquake Waves to Probe the Inner Earth.” Proceedings of the National Academy of Sciences 116 (33): 16159–61. https://doi.org/10.1073/pnas.1909777116.
Scotese, Christopher R. 2016. “PALEOMAP PaleoAtlas for GPlates and the PaleoData Plotter Program.” http://www.earthbyte.org/paleomap‐ paleoatlas‐for‐gplates.
Smith, P. L., and Howard W. Tipper. 1986. “Plate Tectonics and Paleobiogeography Early Jurassic (Pliensbachian) Endemism and Diversity.” Palaios 1: 399–412.
Snider-Pellegrini, Antonio. 1858. La Création Et Ses Mystères Dévoilés: Ouvrage Où l’on Expose Clairement La Nature de Tous Les Êtres, Les Éléments Dont Ils Sont Composés Et Leurs Rapports Avec Le Globe Et Les Astres, La Nature Et La Situation Du Feu Du Soleil, l’origine de l’Amérique, Et de Ses Habitants Primitifs, La Formation Forcée de Nouvelles Planètes, l’origine Des Langues Et Les Causes de La Variété Des Physionomies, Le Compte Courant de l’homme Avec La Terre, Etc. Librairie A. Franck.
Torsvik, Trond H., Bernhard Steinberger, Grace E. Shephard, Pavel V. Doubrovine, Carmen Gaina, Mathew Domeier, Clinton P. Conrad, and William W. Sager. 2019. “Pacific-Panthalassic Reconstructions: Overview, Errata and the Way Forward.” Geochemistry, Geophysics, Geosystems 20 (7): 3659–89. https://doi.org/10.1029/2019GC008402.
Valdes, Paul J., Christopher R. Scotese, and Daniel J. Lunt. 2021. “Deep Ocean Temperatures Through Time.” Climate of the Past 17 (4): 1483–1506. https://doi.org/10.5194/cp-17-1483-2021.
Wegener, Alfred. 1912. “Die Entstehung Der Kontinente.” Geologische Rundschau 3 (4): 276–92. https://doi.org/10.1007/BF02202896.

GPlates - System Erde III. 2023