Geology News - Earth Science Current Events

One of the best learning documents for global climate change is available at the Manchester Metropolitan University website. Their Global Climate Change Student Guide provides a comprehensive overview of this important subject. The contents of their guide consist of...

• Introduction
• Climate System
• Causes of Climate Change
• Empirical Study of Climate
• Climate Modeling
• Palaeoclimatic Change
• Contemporary Climate Change
• Epilogue

(From Chapter 1) The overall state of the of the global climate is determined by the balance of solar and terrestrial radiation budgets. How this energy balance is regulated depends upon the fluxes of energy, moisture, mass and momentum within global climate system, made up of its 5 components, the atmosphere, the oceans, the cryosphere, the biosphere and the geosphere.

Arguably there is a sixth component, an anthropogenic system, mankind. In the last 200 years, through increased utilization of the world's resources, humans have begun to influence the global climate system, primarily by increasing the Earth's natural greenhouse effect.

(From Chapter 6) If climate model projections prove to be even moderately accurate, global temperatures by the end of the next century will be higher than at any time during the last 120,000 years.... Failure to introduce some form of global greenhouse gas emission reduction strategy will merely extend the time frame of anthropogenic global warming that humanity may already be witnessing.

I believe that this document is worth the attention of anyone interested in learning more about global climate change. As shown in the quote above it addresses the many causes of global climate change and provides a projection for the future. Read the Global Climate Change Student Guide at the Manchester Metropolitan University website.

Labels: Global-Warming, Meteorology, Oceanography

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Image by USGS

USGS has an interesting article on the global transport of dust and its impact upon human health and coral reefs. Dust storms in the Sahara and Gobi Deserts can drive tons of dust particles high into the atmosphere and into long distance transport. Dusts from the African Sahara and Sahel are reaching the Caribbean and southern US states where they can damage coral reefs and cause respiratory problems in humans. Also, dusts from the Asian Gobi and Takli Makan deserts are reaching the Hawaiian Islands and western US states.

Hundreds of millions of tons of dust are making these long-distance trips each year. Evidence suggests that these dusts are responsible at least in part for a dramatic decline in coral reef health in the Caribbean and the incidence of respiratory problems in humans.

A sandstorm in the northwest African desert pushes tons of dust out over the Atlantic. Some of this dust could reach the Caribbean Islands and eastern United States. Image by NASA.

The USGS website has a good presentation on this topic which includes satellite images, data, graphs, descriptions and video interviews with the scientists who promote these ideas. Learn more about this airborne dust at the USGS website.

Labels: Meteorology, Oceanography

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Screenshot of chevron structures located at the southern tip of Madagascar from Google Maps. Click the image for detail.

Members of the Holocene Impact Working Group have identified numerous shoreline structures that they believe are evidence of recent marine impact events. These structures that they refer to as "chevrons" are believed to be piles of sediment that have been swept into chevron-shaped ridges by the tsunami-size waves produced from these impacts. The chevrons contain sediments, deep ocean microfossils and bits of what appear to be impact debris that are combined without regard to the normal superposition sequence.

The working group has identified numerous chevron locations - so many that it causes them to question just how often the Earth is subject to massive impact events. In addition, the size of some chevrons are enormous. Some are hundreds of feet in height and covering hundreds of acres each - large enough that they would require a tsunami over 100 feet high to construct them. These chevron structures are reported at numerous locations in Australia, New Zealand, Vietnam, India, Southern Africa, Madagascar, Hawaii, Portugal, Algeria, United Kingdom, Denmark, Brazil, Mexico, California, Washington, Oregon and other locations.


Landsat image of the Fenambosy Chevrons in Madagascar by USGS. The open side of these chevrons point directly
at a crater at the bottom of the Indian Ocean. They suggest a gigantic meteor impact occurred about 4800 years ago.
Higher resolution image.
You can read more about these chevron structures and see a world map with their locations in an article on the International Herald Tribune website. You can also visit a chevron location by clicking the google map image at the top of this article.

Related content on Geology.com: Zoom in on fifty of Earth's most obvious meteor impact structures with our Google Map of Meteor Impact Structures.

Labels: Meteor-Meteorite, Oceanography, Satellite-Images

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The United States Geological Survey has released a new report: USGS Open File Report 206-1219 - "Historical Shoreline Change and Associated Coastal Land Loss Along Sandy Shorelines of the California Coast". This report documents change on over 450 miles of California shoreline. According to the report, 66 percent of California's beaches are eroding.

The estimated average rate of long term shoreline change for the state was 0.2 meters per year - an accretional trend. This trend was most likely due to changes in the large volumes of sediment that are added to the shoreline system by large rivers and to impact by beach nourishment projects. The short term shoreline change was -0.2 meters per year - an erosional trend. Some of this has been attributed to local nourishment projects that have been stopped or slowed in recent years.


Image by USGS
The report contains many photos, graphs, maps, data tables and graphics related to California shorelines and the shoreline erosion problem (.pdf link).

Labels: Coastal-Geology, Oceanography

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Map of the Arctic Ocean and North Pole. Image by CIA

The North Pole is often thought of as a place that is inaccessible - unless you have a submarine or the ability and courage to travel there over the ice. Satellite images taken last month from ESA's Envisat and EOS Aqua satellites show that the Arctic Ocean was clear enough of ice that a ship could sail from locations in northern Europe directly to the North Pole.

This adds to the accumulating evidence that the northern polar ice cover is shrinking as a result of global warming. There are many downsides to global warming but a tiny upside would be opening of The Northwest Passage, a sea route connecting the Atlantic and Pacific Oceans through the Arctic Archipelago of Canada and the Northern Sea Route, a shipping lane between the Atlantic and Pacific Oceans along the northern margins of Europe and Asia.

Read the full article on Ice in the Arctic Ocean at Yahoo! News.

Labels: Arctic-Antarctic, Global-Warming, Oceanography

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The National Science Foundation has announced that the Joides Resolution, a scientific ocean drilling vessel, will be renovated. The ship has a twenty year history of service to the geology and oceanography communities. Its main work has been in deep ocean drilling to retrieve samples of Earth's crust and sea-floor sediments. The renovation will increase laboratory space by at least 50 percent, install an enhanced drilling instrumentation system, a sub-sea camera system with improved handling, and a new drill string with upgraded drilling tools. These will allow for faster and more efficient drilling and core recovery. Changes in the hull will also be done to improve fuel efficiency and speed.

Joides Resolution Image by USGS

Labels: Oceanography

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Joshua Schwartz and Mike Cheadle of the University of Wyoming are members of an author team reporting that they have found a more reliable method for estimating the age of oceanic crust. This method is based upon finding zircon crystals in the rock and using them for age determination. They report that a reliable age can be determined more than 99% of the time.

Traditional methods of dating the oceanic crust are based upon magnetic measurements along with a history of Earth's polarity reversals. Schwartz says "Our finding that these zircons are older than they should be relative to their magnetic age alters what we've thought about oceanic crust."

Image from NSFRead more about this new method for dating the oceanic crust at the NSF website.

Labels: Oceanography

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The Integrated Ocean Drilling Program (IODP) is preparing Chikyu, a deep sea drilling vessel, capable of penetrating the oceanic crust to levels deeper than any previous drilling ship or platform. Capable of handling 12,000 meters of drill string and 4,000 meters of riser Chikyu will be well equipped for sampling deep sea sediment, exploring the oceanic crust, and a possible attempt to be the first successful penetration of Earth's mantle.

Anyone interested in deep sea drilling should visit the IODP website. They have lots of interesting facts about deep sea drilling, IODP expeditions, and a scientific report and prospectus collection which includes information on Juan de Fuca Hydrogeology, Arctic Coring Expedition, North Atlantic Climate, Ocean Core Complex Formation, Modern Carbonate Mounds: Porcupine Drilling, Gulf of Mexico Hydrogeology, Superfast Spreading Rate Crust, Tahiti Sea Level Provisional Prospectus and Cascadia Margin Gas Hydrates. Perhaps the most interesting and educational resources on the site are the videos on Deep Sea Drilling and Rotary Drilling. IODP is also sponsor of the Teachers-at-Sea Programs.
Visit the Integrated Ocean Drilling Program website.

Labels: Oceanography

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