June 2011 GSA Today science article includes exclusive lithoprobe poster

May 27, 2011

Boulder, CO, USA - What would we see and what would we learn if we were able to cut North America in half, pull it apart, and look at the resulting cross section through the continent, from the surface all the way down to its very deepest mantle roots? Although it sounds like an impossible undertaking, Philip Hammer of the University of British Columbia and colleagues have done just that.

In the June issue of GSA Today:
The big picture: A lithospheric cross section of the North American continent
Philip T.C. Hammer et al., Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver, BC V6T 1Z4, Canada; doi: 10.1130/GSATG95A.1,
www.geosociety.org/gsatoday/.

Utilizing geological and geophysical data collected over more than 20 years as part of the Canadian LITHOPROBE project, Hammer and colleagues have constructed a curved cross-section (to account for the curvature of Earth's surface) that extends from the Cascadia subduction zone on the west coast, east to the Atlantic margin, and down to depths as great as 270 km to the very base of the North American tectonic plate.

A detailed, 36-by-16-inch poster illustrating this cross section accompanies the issue and can also be downloaded from the GSA Today website, www.geosociety.org/gsatoday/.

What can be learned from this cross section? Both the mantle roots of the continent, as well as the overlying continental crust, bear the scars of ancient continental collisions and eons of oceanic subduction, two processes that remain such a recognizable part of modern plate tectonics. It appears that the processes that continue to shape the continent today have been active through more than three billion years of Earth's history.

But there are mysteries hidden in the cross section as well. Those deformed and faulted segments of crust that record the growth of our continent are now devoid of the deep crustal roots produced during continental collision. Instead of deep mountain roots, it appears that the base of the continental crust is flat. Understanding the fate of the crustal underpinnings of ancient mountain systems, and determining the processes that flatten the base of the crust, remains but one of numerous puzzles of continental evolution that have yet to be resolved.
-end-
Peer-reviewed GSA Today articles are open access. Please discuss articles of interest with the authors before publishing stories on their work, and please make reference to GSA Today in articles published. Contact Christa Stratton for additional information or assistance.

www.geosociety.org

Geological Society of America

Related Continental Crust Articles from Brightsurf:

Seismic data explains continental collision beneath Tibet
New imagery reveals the causes of seismic activity deep beneath the Himalaya region, contributing to an ongoing debate over the continental collision process when two tectonic plates crash into each other.

Artificial intelligence learns continental hydrology
The data sets on the Earth's gravitational field which are required for this, stem from the GRACE and GRACE-FO satellite missions.

Coordination helps avoid continental COVID-19 resurgence, European modeling study shows
Coordinated lockdown strategies among countries is key to preventing resurgent COVID-19 outbreaks in continental Europe, a new modeling study shows.

A continental-scale prediction on the functional diversity of stream microbes
Climate mediates continental scale patterns of stream microbial functional diversity.

New insights into the formation of Earth's crust
New research from Mauricio Ibanez-Mejia at the University of Rochester gives scientists better insight into the geological processes responsible for the formation of Earth's crust.

High-tech material in a salt crust
MAX phases unite the positive properties of ceramics and metals.

Earth's continental nurseries discovered beneath mountains
Earth is the only known planet with continents, and Rice University scientists are offering up new evidence that Earth's continental crust formed deep below mountainous continental arcs like the Andes.

Innovative tool allows continental-scale water, energy, and land system modeling
A new large-scale hydroeconomic model, developed by the Water Program at IIASA, will allow researchers to study water systems across whole continents, looking at sustainability of supply and the impacts of water management on the energy and agricultural sectors.

Creating a continental bird migration forecast
September is the peak of autumn bird migration, and billions of birds are winging their way south in dramatic pulses.

Continental microbes helped seed ancient seas with nitrogen
ASU researcher Ferran Garcia-Pichel, along with Christophe Thomazo, from the Laboratoire Biogéosciences in Dijon, France, and Estelle Couradeau, a former Marie Curie postdoc in both labs, show that biological soil crusts -- colonies of microorganisms that today colonize arid, desert environments -- may have played a significant role in the Earth's nitrogen cycle, helping to fertilize early oceans and create a nutrient link between atmosphere, continents and oceans.

Read More: Continental Crust News and Continental Crust Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.