Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

University of Leicester geologists demonstrate extent of ancient ice age

18.06.2009
Team investigates the climate of planet Earth 440 million years ago
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.

They have published their findings and are due to discuss them at a public lecture at the University on Wednesday June 17.

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 in the Ken Edwards Lecture Theatre 3, University of Leicester. Lecture time: 5.30pm-6.30pm on Wednesday June 17.

Alex Page | EurekAlert!
Further information:
http://www.cam.ac.uk

Further reports about: AGE Arabia CO2 Lecture Ordovician Palaeozoic crystalline dead zone ice age ice sheet icehouse surface water

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: It’s All in the Mix: Jülich Researchers are Developing Fast-Charging Solid-State Batteries

There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.

The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

A novel synthetic antibody enables conditional “protein knockdown” in vertebrates

20.08.2018 | Life Sciences

Metamolds: Molding a mold

20.08.2018 | Information Technology

It’s All in the Mix: Jülich Researchers are Developing Fast-Charging Solid-State Batteries

20.08.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>