Featured Research

from universities, journals, and other organizations

How Earth might have looked: How a failed Saharan Atlantic Ocean rift zone sculped Africa's margin

Date:
February 28, 2014
Source:
Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences
Summary:
Break-up of the supercontinent Gondwana about 130 Million years ago could have led to a completely different shape of the African and South American continent with an ocean south of today’s Sahara desert, as geoscientists have shown through the use of sophisticated plate tectonic and three-dimensional numerical modelling.

A hypothetical model of the circum-Atlantic region at present-day, if Africa had split into two parts along the West African Rift system. Here, the north-west part of present day Africa would have moved with the South American continent, forming a "Saharan Atlantic ocean".
Credit: Sascha Brune/Christian Heine

Break-up of the supercontinent Gondwana about 130 Million years ago could have lead to a completely different shape of the African and South American continent with an ocean south of today's Sahara desert, as geoscientists from the University of Sydney and the GFZ German Research Centre for Geosciences have shown through the use of sophisticated plate tectonic and three-dimensional numerical modelling.

The study highlights the importance of rift orientation relative to extension direction as key factor deciding whether an ocean basin opens or an aborted rift basin forms in the continental interior.

For hundreds of millions of years, the southern continents of South America, Africa, Antarctica, Australia, and India were united in the supercontinent Gondwana. While the causes for Gondwana's fragmentation are still debated, it is clear that the supercontinent first split along along the East African coast in a western and eastern part before separation of South America from Africa took place. Today's continental margins along the South Atlantic ocean and the subsurface graben structure of the West African Rift system in the African continent, extending from Nigeria northwards to Libya, provide key insights on the processes that shaped present-day Africa and South America.

Christian Heine (University of Sydney) and Sascha Brune (GFZ) investigated why the South Atlantic part of this giant rift system evolved into an ocean basin, whereas its northern part along the West African Rift became stuck.

"Extension along the so-called South Atlantic and West African rift systems was about to split the African-South American part of Gondwana North-South into nearly equal halves, generating a South Atlantic and a Saharan Atlantic Ocean," geoscientist Sascha Brune explains. "In a dramatic plate tectonic twist, however, a competing rift along the present-day Equatorial Atlantic margins, won over the West African rift, causing it to become extinct, avoiding the break-up of the African continent and the formation of a Saharan Atlantic ocean."

The complex numerical models provide a strikingly simple explanation: the larger the angle between rift trend and extensional direction, the more force is required to maintain a rift system. The West African rift featured a nearly orthogonal orientation with respect to westward extension which required distinctly more force than its ultimately successful Equatorial Atlantic opponent.


Story Source:

The above story is based on materials provided by Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences. Note: Materials may be edited for content and length.


Journal Reference:

  1. C. Heine, S. Brune. Oblique rifting of the Equatorial Atlantic: Why there is no Saharan Atlantic Ocean. Geology, 2014; 42 (3): 211 DOI: 10.1130/G35082.1

Cite This Page:

Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences. "How Earth might have looked: How a failed Saharan Atlantic Ocean rift zone sculped Africa's margin." ScienceDaily. ScienceDaily, 28 February 2014. <www.sciencedaily.com/releases/2014/02/140228210545.htm>.
Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences. (2014, February 28). How Earth might have looked: How a failed Saharan Atlantic Ocean rift zone sculped Africa's margin. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2014/02/140228210545.htm
Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences. "How Earth might have looked: How a failed Saharan Atlantic Ocean rift zone sculped Africa's margin." ScienceDaily. www.sciencedaily.com/releases/2014/02/140228210545.htm (accessed July 30, 2014).

Share This




More Earth & Climate News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
Powered by NewsLook.com
In Virginia, the Rise of a New Space Coast

In Virginia, the Rise of a New Space Coast

AP (July 30, 2014) Every summer, tourists make the pilgrimage to Chincoteague Island, Va. to see wild ponies cross the Assateague Channel. But, it's the rockets sending to supplies to the International Space Station that are making this a year-round destination. (July 30) Video provided by AP
Powered by NewsLook.com
Climate Change Could Cost Billions, According To White House

Climate Change Could Cost Billions, According To White House

Newsy (July 29, 2014) A report from the White House warns not curbing greenhouse gas emissions could cost the U.S. billions. Video provided by Newsy
Powered by NewsLook.com
Climate Change Could Cost Billions According To White House

Climate Change Could Cost Billions According To White House

Newsy (July 29, 2014) A report from the White House warns not curbing greenhouse gas emissions could cost the U.S. billions. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



    Save/Print:
    Share:

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins