Featured Research

from universities, journals, and other organizations

Ancient Ice Age, Once Regarded As Brief 'Blip' Found To Have Lasted For 30 Million Years

Date:
June 17, 2009
Source:
University of Leicester
Summary:
Geologists have shown that an ancient ice age, once regarded as a brief "blip," in fact lasted for 30 million years.

Geologists at the University of Leicester have shown that an ancient Ice Age, once regarded as a brief 'blip', in fact lasted for 30 million years.

Their research suggests that during this ancient Ice Age, global warming was curbed through the burial of organic carbon that eventually lead to the formation of oil – including the 'hot shales' of north Africa and Arabia which constitute the world's most productive oil source rock.

This ice age has been named 'the Early Palaeozoic Icehouse' by Dr Alex Page and his colleagues in a paper published as part of a collaborative Deep Time Climate project between the University of Leicester and British Geological Survey.

The Ice Age occurred in the Ordovician and Silurian Periods of geological time (part of the Early Palaeozoic Era), an interval that witnessed a major diversification of early marine animals including trilobites and primitive fish as well as the emergence of the first land plants.

The Early Palaeozoic climate had long been considered characterised by essentially greenhouse conditions with elevated atmospheric CO2 and warm temperatures extending to high latitudes, and only brief snaps of frigid climate. However, during his doctoral studies in the internationally renowned Palaeobiology Research Group of the University of Leicester, Department of Geology, Alex Page and his colleagues Jan Zalasiewicz and Mark Williams demonstrated how the ice age was probably of much longer duration.

The team demonstrated that the Late Ordovician and Early Silurian Epochs were characterised by widespread ice formation, with changes in the extent of continental glaciation resulting in rapid sea¬ level changes around the globe.

They compared evidence of sea-level change from the rock record of ancient coastlines with evidence of sediments being deposited by glacial meltwaters or ice¬rafting at high latitudes, and with chemical indicators of temperature in the strata.

The team showed that although the Early Palaeozoic Icehouse was of similar extent and duration to the modern ice age, the workings of the carbon cycle appeared markedly different to that of the present day. Unlike the modern oceans, the oceans of the Early Palaeozoic were often oxygen-starved 'dead zones' leading to the burial of plankton-derived carbon in the sea floor sediments. The strata produced in this way include the 'hot shales' of north Africa and Arabia which constitute the world's most productive oil source rock. In fact, the burial of organic carbon derived from fossil plankton may have served to draw down CO2 from the atmosphere to promote cooling during the Early Palaeozoic Icehouse.

Page commented: "These fossil fuel- rich deposits formed during relatively warmer episodes during the Early Palaeozoic Icehouse when the partial melting of ice sheets brought about rapid sea-level rise. This melt-water may have bought a massive influx of nutrients into the surface waters, allowing animals and algae to thrive and bloom in the plankton, but also altered ocean circulation, creating oxygen-poor deep waters which facilitated the preservation of fragile, carbonaceous planktonic fossils. The deglacial outwash formed a less dense, low-salinity 'lid' on the oceans preventing atmospheric oxygen penetrating to the seafloor. The absence of oxygen under such conditions served to shut down decay accounting for the preservation of these fossils."

Page added that the burial of oil shales in deglacial anoxia "may have been a negative feedback mechanism that prevented runaway warming, meaning that in the Early Palaeozoic Icehouse at least, processes eventually leading to oil formation may have been the solution to the greenhouse effect."

Alex Page's research will be presented at the Doctoral Inaugural Lectures being held at the University of Leicester. on June 17.  They have also published their findings.


Story Source:

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


Cite This Page:

University of Leicester. "Ancient Ice Age, Once Regarded As Brief 'Blip' Found To Have Lasted For 30 Million Years." ScienceDaily. ScienceDaily, 17 June 2009. <www.sciencedaily.com/releases/2009/06/090616103307.htm>.
University of Leicester. (2009, June 17). Ancient Ice Age, Once Regarded As Brief 'Blip' Found To Have Lasted For 30 Million Years. ScienceDaily. Retrieved April 19, 2014 from www.sciencedaily.com/releases/2009/06/090616103307.htm
University of Leicester. "Ancient Ice Age, Once Regarded As Brief 'Blip' Found To Have Lasted For 30 Million Years." ScienceDaily. www.sciencedaily.com/releases/2009/06/090616103307.htm (accessed April 19, 2014).

Share This



More Earth & Climate News

Saturday, April 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Drought Concerns May Hurt Lake Tourism

Drought Concerns May Hurt Lake Tourism

AP (Apr. 18, 2014) — Operators of recreational businesses on western reservoirs worry that ongoing drought concerns will keep boaters and other visitors from flocking to the popular summer attractions. (April 18) Video provided by AP
Powered by NewsLook.com
Man Claims He Found Loch Ness Monster With... Apple Maps?

Man Claims He Found Loch Ness Monster With... Apple Maps?

Newsy (Apr. 18, 2014) — Andy Dixon showed the Daily Mail a screenshot of what he believes to be the mythical beast swimming just below the lake's surface. Video provided by Newsy
Powered by NewsLook.com
First Ever 'Female Penis' Discovered In Animal Kingdom

First Ever 'Female Penis' Discovered In Animal Kingdom

Newsy (Apr. 18, 2014) — Not only are these newly discovered bugs' sex organs reversed, but they also mate for up to 70 hours. Video provided by Newsy
Powered by NewsLook.com
Ark. Man Finds 6-Carat Diamond At State Park

Ark. Man Finds 6-Carat Diamond At State Park

Newsy (Apr. 18, 2014) — An Arkansas man has found a nearly 6.2-carat diamond, which he dubbed "The Limitless Diamond," at the Crater of Diamonds State Park. 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