Younger, hotter Earth still not understood

Sep 13, 2010
Younger, hotter Earth still not understood
Satellite image of the Hudson Bay region. (Image by NASA)

Plate tectonics may not have operated on a younger and hotter Earth according to new research from the University of Bristol carried out on preserved remnants of ancient continental crust in the Hudson Bay region of Canada.

The processes that formed and shaped the early ’s crust are still poorly understood, and the onset of plate tectonics has been estimated as being as early as the Hadean (4.6-3.8 billion years ago) or as late as the Neoproterozoic (1,000-542 million years ago).

The Hudson Bay region represents an excellent opportunity to investigate crustal formation during the (that is from the formation of the Earth, almost 4.6 billion years ago, until 542 million years ago).  It records tectonic events leading to the formation and stabilisation of the Laurentian continent (most of modern-day North America) and also preserves crust with ages spanning around 2 billion years.

David Thompson, a PhD student in Bristol’s Department of , and colleagues from the University of Calgary and the Geological Survey of Canada analysed the structure and thickness of the crust using seismic waves to investigate what tectonic process were operating on the younger Earth.

They found that the crust between 3.9 and 2.7 billion years old had a relatively simple structure with no clear signs that it was subjected to the kind of plate tectonic processes operating now.  The crust that formed about 1.8 billion years, however, showed evidence of the collision of two continents, similar to the collision between India and Asia still ongoing today.

The researchers then compared the observed structure of the Hudson Bay crust with of a similar age found elsewhere in the world. They concluded that modern-style plate tectonics may not have been established until as late as 1.8 billion years ago.

The research is published in and was named as one of the Nature Geoscience's research highlights in their September issue.

Explore further: NASA balloons begin flying in Antarctica for 2014 campaign

More information: Precambrian crustal evolution: Seismic constraints from the Canadian Shield by D.A. Thompson, I.D. Bastow, G. Helffrich, J-M. Kendall, J. Wookey, D.B. Snyder, D.W. Eaton Earth and Planetary Science Letters 297 (2010) 655-666. www.sciencedirect.com/science/journal/0012821X

Related Stories

Bias in the rock record?

Jan 14, 2009

(PhysOrg.com) -- The fossil record is known to be biased by the unevenness of geographical and stratigraphical sampling, and the lack of exposed rocks containing fossils. In a recent Perspective in Science [2 Jan ...

Mapping Venus: Extreme makeover or plate tectonics?

Mar 22, 2010

(PhysOrg.com) -- Venus and Earth have long been thought of as sister planets. Given its similar size and proximity to Earth in the inner Solar System, Venus might seem like a promising candidate for having ...

Study reveals ancient rocks linked to old Earth's crust

Feb 24, 2010

(PhysOrg.com) -- A new geological study which took place in the Pilbara region of Western Australia brings us one step closer to understanding more precisely the timing of when the primordial earth crust was ...

Mediterranean Sea dried up five million years ago

Feb 16, 2009

(PhysOrg.com) -- Upward movement of the Earth's crust transformed the Straits of Gibraltar into a dam. Approximately five million years ago, the Mediterranean Sea dried up after it was sealed off from the Atlantic Ocean. ...

Recommended for you

Scientists make strides in tsunami warning since 2004

8 hours ago

The 2004 tsunami led to greater global cooperation and improved techniques for detecting waves that could reach faraway shores, even though scientists still cannot predict when an earthquake will strike.

Trade winds ventilate the tropical oceans

8 hours ago

Long-term observations indicate that the oxygen minimum zones in the tropical oceans have expanded in recent decades. The reason is still unknown. Now scientists at the GEOMAR Helmholtz Centre for Ocean Research ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.