Featured Research

from universities, journals, and other organizations

Gondwana Remnants In Alabama And Georgia: Uchee Is An 'Exotic' Peri-Gondwanan Arc Terrane, Not Part Of Laurentia

Date:
February 4, 2008
Source:
Geological Society of America
Summary:
In 1964, an exploratory petroleum well was drilled through one mile of Gulf Coastal Plain sediments in southeastern Alabama. The retrieved core included Silurian to Devonian sedimentary rocks that surprisingly contain fossils provincial to proto-Africa (i.e., Gondwanan), rather than proto-North America (Laurentian), setting off a scientific debate about how these rocks got there. At the same time, discoveries made in studies of the ocean floor were being formulated into the sea-floor spreading mechanism that would explain why and how continents drift around the surface of Earth, the missing link that had escaped Alfred Wegner's conceptualization of continental drift.

In 1964, an exploratory petroleum well was drilled through one mile of Gulf Coastal Plain sediments in southeastern Alabama. The retrieved core included Silurian to Devonian sedimentary rocks that surprisingly contain fossils provincial to proto-Africa (i.e., Gondwanan), rather than proto-North America (Laurentian), setting off a scientific debate about how these rocks got there.

At the same time, discoveries made in studies of the ocean floor were being formulated into the sea-floor spreading mechanism that would explain why and how continents drift around the surface of Earth, the missing link that had escaped Alfred Wegner’s conceptualization of continental drift.

The Suwannee terrane, as the Alabama rocks became known, figured prominently in J. Tuzo Wilson’s 1966 article in Nature (“Did the Atlantic close and reopen?”), which led Kevin Burke to later coin the term “Wilson Cycle.”

This orphaned block of Gondwanan crust is now known to extend in the subsurface beneath southern Alabama, Georgia, and South Carolina.

A collage of deformed and metamorphosed fragments of ancient volcanic island arcs, known collectively as Carolinia (i.e., Carolina Superterrane), form the most eastern exposures of the Appalachian orogen and also project to depth beneath the Atlantic coastal plain.

These arc terranes formed in an ancient ocean peripheral to western Gondwanaland prior to its climactic Appalachian collision with Laurentia that consolidated the supercontinent Pangaea.

Due to the lack of fossils and reliable isotopic dates within these terranes, the nature and timing of their docking with Laurentia are controversial; hence, one of the most significant events in Appalachian history is also one of the least understood.

Steltenpohl and others report* new isotopic and structural information on the poorly known Uchee terrane in Alabama that bears on the problem.

The Uchee terrane occupies a particularly critical tectonic position, being sandwiched between Laurentian continental basement exposed in the Pine Mountain window and Gondwanan crust of the overlying, albeit buried, Suwannee terrane.

Steltenpohl and coauthors confirm that the Uchee is an “exotic” peri-Gondwanan arc terrane -- not part of Laurentia as was previously believed -- and thus provide a new puzzle piece that helps to constrain models for plate tectonic development of the Pangaean suture.

*This research was authored by Mark G. Steltenpohl (Auburn University) et al. and published in the February issue of Geosphere, a journal of the Geological Society of America.


Story Source:

The above story is based on materials provided by Geological Society of America. Note: Materials may be edited for content and length.


Cite This Page:

Geological Society of America. "Gondwana Remnants In Alabama And Georgia: Uchee Is An 'Exotic' Peri-Gondwanan Arc Terrane, Not Part Of Laurentia." ScienceDaily. ScienceDaily, 4 February 2008. <www.sciencedaily.com/releases/2008/02/080204212810.htm>.
Geological Society of America. (2008, February 4). Gondwana Remnants In Alabama And Georgia: Uchee Is An 'Exotic' Peri-Gondwanan Arc Terrane, Not Part Of Laurentia. ScienceDaily. Retrieved September 1, 2014 from www.sciencedaily.com/releases/2008/02/080204212810.htm
Geological Society of America. "Gondwana Remnants In Alabama And Georgia: Uchee Is An 'Exotic' Peri-Gondwanan Arc Terrane, Not Part Of Laurentia." ScienceDaily. www.sciencedaily.com/releases/2008/02/080204212810.htm (accessed September 1, 2014).

Share This




More Earth & Climate News

Monday, September 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Iceland Lowers Aviation Alert on Volcano

Iceland Lowers Aviation Alert on Volcano

AFP (Sep. 1, 2014) Iceland has lowered its aviation alert on its largest volcano after a fresh eruption on a nearby lava field prompted authorities to enforce a flight ban for several hours. Duration: 01:07 Video provided by AFP
Powered by NewsLook.com
Lightning Hurts 3 on NYC Beach

Lightning Hurts 3 on NYC Beach

AP (Sep. 1, 2014) A lightning strike injured three people on a New York City beach on Sunday. The storms also delayed flights and interrupted play at the US Open tennis tournament. (Sept. 1) Video provided by AP
Powered by NewsLook.com
Thailand Totters Towards Waste Crisis

Thailand Totters Towards Waste Crisis

AFP (Sep. 1, 2014) Fears are mounting in Bangkok that poor planning and lax law enforcement are tipping Thailand towards a waste crisis. Duration: 01:21 Video provided by AFP
Powered by NewsLook.com
Washington Wildlife Center Goes Nuts Over Baby Squirrels

Washington Wildlife Center Goes Nuts Over Baby Squirrels

Reuters - US Online Video (Aug. 30, 2014) An animal rescue in Washington state receives an influx of orphaned squirrels, keeping workers busy as they nurse them back to health. Rough Cut (no reporter narration). Video provided by Reuters
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