British-Australian team of scientists has revealed the past position of the Australian, Antarctic and Indian tectonic plates at 165 million years ago, demonstrating how they formed the supercontinent Gondwana.
The supercontinent Gondwana (Lenny)
The study, published in the journal Gondwana Research, helps clear up previous uncertainties on how these plates evolved and where they should be positioned when drawing up a picture of the past.
“The Earth’s tectonic plates move around through time. As these movements occur over many millions of years, it has previously been difficult to produce accurate maps of where the continents were in the past,” explained study lead author Dr Lloyd White from the University of London.
“We used a computer program to move geological maps of Australia, India and Antarctica back through time and built a ‘jigsaw puzzle’ of the supercontinent Gondwana. During the process, we found that many existing studies had positioned the plates in the wrong place because the geological units did not align on each plate.”
The team adopted an old technique used by researchers who discovered the theories of continental drift and plate tectonics, but which had largely been ignored by many modern scientists.
“It was a simple technique, matching the geological boundaries on each plate. The geological units formed before the continents broke apart, so we used their position to put this ancient jigsaw puzzle back together again,” Dr White said.
“It is important that we know where the plates existed many millions of years ago, and how they broke apart, as the regions where plates break are often where we find major oil and gas deposits, such as those that are found along Australia’s southern margin.”
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Bibliographic information: White LT et al. A reassessment of paleogeographic reconstructions of eastern Gondwana: Bringing geology back into the equation. Gondwana Research, published online July 1, 2013; doi: 10.1016/j.gr.2013.06.009
