Featured Research

from universities, journals, and other organizations

Scientists find slow subsidence of Earth's crust beneath the Mississippi delta

Date:
April 2, 2012
Source:
National Science Foundation
Summary:
The Earth's crust beneath the Mississippi Delta sinks at a much slower rate than what had been assumed. The researchers arrived at their conclusions by comparing detailed sea-level reconstructions from different portions of coastal Louisiana.

Aerial view of Delacroix, Louisiana, mostly abandoned due to sea-level rise and wetland loss.
Credit: Tor Törnqvist

Earth's crust beneath the Mississippi Delta sinks at a much slower rate than what had been assumed.

That's one of the results geoscientists report April 2 in a paper published in the journal Earth and Planetary Science Letters.

The researchers arrived at their conclusions by comparing detailed sea-level reconstructions from different portions of coastal Louisiana.

"The findings demonstrate the value of research on different facets of Earth system dynamics over long time periods," says Thomas Baerwald, geography and spatial sciences program director at the National Science Foundation (NSF).

NSF's Directorates for Geosciences and for Social, Behavioral & Economic Sciences funded the research.

"The results provide valuable new insights about the factors that affect shorelines and other locations in the Gulf Coast area now and into the future," says Baerwald.

"Our study shows that the basement underneath key portions of the Mississippi Delta, including the New Orleans area, has subsided less than one inch per century faster over the past 7,000 years than the more stable area of southwest Louisiana," says paper co-author Torbjörn Törnqvist of Tulane University.

The difference is much lower than previously believed.

"Other studies have assumed that a large portion of the Earth's crust underneath the Mississippi Delta subsided at least 30 times faster due to the weight of rapidly accumulating sediments in the delta," says Törnqvist.

The paper, co-authored by Tulane scientists Shi-Yong Yu and Ping Hu, reveals some good news for residents of the New Orleans area.

Large structures such as coastal defense systems could be relatively stable, provided they are anchored in the basement at a depth of 60-80 feet below the land surface.

Shallower, water-rich deposits subside much more rapidly.

However, the study also provides more sobering news.

"These subsidence rates are small compared to the rate of present-day sea-level rise from the Florida panhandle to east Texas," says Törnqvist.

"The rate of sea-level rise in the 20th century in this region has been five times higher compared to the pre-industrial millennium as a result of human-induced climate change."

Sea level has risen more than eight inches during the past century.

"Looking forward 100 years, our main concern is the continued acceleration of sea-level rise due to global warming, which may amount to as much as three to five feet," says Törnqvist.

"We can now show that sea-level rise has already been a larger factor in the loss of coastal wetlands than was previously believed."


Story Source:

The above story is based on materials provided by National Science Foundation. Note: Materials may be edited for content and length.


Journal Reference:

  1. Shi-Yong Yu, Torbjörn E. Törnqvist, Ping Hu. Quantifying Holocene lithospheric subsidence rates underneath the Mississippi Delta. Earth and Planetary Science Letters, 2012; 331-332: 21 DOI: 10.1016/j.epsl.2012.02.021

Cite This Page:

National Science Foundation. "Scientists find slow subsidence of Earth's crust beneath the Mississippi delta." ScienceDaily. ScienceDaily, 2 April 2012. <www.sciencedaily.com/releases/2012/04/120402124452.htm>.
National Science Foundation. (2012, April 2). Scientists find slow subsidence of Earth's crust beneath the Mississippi delta. ScienceDaily. Retrieved July 24, 2014 from www.sciencedaily.com/releases/2012/04/120402124452.htm
National Science Foundation. "Scientists find slow subsidence of Earth's crust beneath the Mississippi delta." ScienceDaily. www.sciencedaily.com/releases/2012/04/120402124452.htm (accessed July 24, 2014).

Share This




More Earth & Climate News

Thursday, July 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Observation Boat to Protect Cetaceans During Ship Transfer

Observation Boat to Protect Cetaceans During Ship Transfer

AFP (July 22, 2014) — As part of the 14-ship convoy that will accompany the Costa Concordia from the port of Giglio to the port of Genoa, there will be a boat carrying experts to look out for dolphins and whales from crossing the path of the Concordia. Duration: 01:02 Video provided by AFP
Powered by NewsLook.com
New Orleans Plans to Recycle Cigarette Butts

New Orleans Plans to Recycle Cigarette Butts

AP (July 21, 2014) — New Orleans is the first U.S. city to participate in a large-scale recycling effort for cigarette butts. The city is rolling out dozens of containers for smokers to use when they discard their butts. (July 21) Video provided by AP
Powered by NewsLook.com
Shark Sightings a Big Catch for Cape Tourism

Shark Sightings a Big Catch for Cape Tourism

AP (July 21, 2014) — A rise in shark sightings along the shores of Chatham, Massachusetts is driving a surge of eager vacationers to the beach town looking to catch a glimpse of a great white. (July 21) Video provided by AP
Powered by NewsLook.com
Spectacular Lightning Storm Hits London

Spectacular Lightning Storm Hits London

AFP (July 19, 2014) — A spectaCular lightning storm struck the UK overnight Friday. Images of lightning strikes over the Shard and Tower Bridge in central London. Duration: 00:23 Video provided by AFP
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