EGAATA-2: THE BRINGING TOGETHER (AND BREAKING APART) OF OUR CONTINENTS

Here is the second ‘Excellent Geophysics Articles As Teaching Aids’ (EGAATA) post.  The point of these posts is to highlight excellent articles that could be a basis for teaching a section on the chosen topic. 

Executive summary: There is widespread acceptance that Pangea was not the only supercontinent in Earth’s history. This review paper highlights the development of ideas regarding the episodicity of tectonic processes, while chronicling some key contributions of the past 10 years.

Title: The supercontinent cycle: A retrospective essay 

Type of article: Review

Published: 2014

Where: Gondwana Research

Authors: R. Damian Nance, J. Brendan Murphy, M. Santosh

Overview: 

A passage in the Introduction sums the paper up well (with refs removed):
“This history of episodic supercontinent assembly and breakup, which constitutes the supercontinent cycle, is now recognized as having profoundly influenced the course of the Earth’s geologic, climatic, and biological evolution. Its existence documents a fundamental aspect of the Earth’s dynamic system and its recognition is arguably the most important development in Earth Science since the introduction of plate tectonics over 40 years ago.” 

The paper outlines the long history of discovery that went into the current thinking. The authors do a great job of outlining the early ideas on the episodicity of tectonic processes. The historical perspective of how we got to where we are today is well needed – credit is given to a number of studies that were not well received at the time.

The authors set up the paper into three parts – Early Ideas, Subsequent Developments (the previous supercontinents), and Modern Views.

Multi-field:

The strength of the paper lies in the analysis of a number of different fields of geoscience in terms of previous and modern theories. The study of thermal heating, sea level, climate change, biodiversity, metamorphism, metallogeny, (to name a few) are all related to the formation and dispersal of supercontinents.

The timing of the release of this review is very well planned – the rise in the number of studies related to the supercontinent cycle allows for a analysis of where we are at with a number of missing questions – the role of subduction, the generation of plumes, the role of internal heating in the break-up of a continents, the introversion and extroversion methods of formation etc, etc.

My own personal opinion is that this paper can be seen as a end-point to this phase of the study of supercontinents. We are on the edge of more revelations – big things are on the horizon and we may need another retrospective soon enough.

Summary:

The article is important in understanding how ideas have developed over time, as well as showing how supercontinent formation and dispersal has an impact on many different fields of geoscience.

Title: The supercontinent cycle: A retrospective essay

Feel free to ask questions in the comments. I can provide further information (and materials) for any high school educators that would be interested in teaching the supercontinent cycle.  

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