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Geology in the News

1. Diamond Discovery | 2. Coal for Electricity
3. History's Deadliest Earthquake | 4. Oldest Sharks
5. Vanishing Salt Flats | 6. Did the Himalayas cause the Ice Age?
7. Feathered Dinosaurs?

Much more and updated info at

Geology.com

1. Diamond Discovery

The eighth largest diamond ever found in North America was recently discovered in Colorado. According to Lynn Bronikowski in the Rocky Mountain News, the 14.2-carat diamond was found at Kelsey Lake, northwest of Fort Collins near the Wyoming border in the Laramie Range.

This mine is the only commercial diamond mine in the United States, and it will not be fully operational until about 1997, when the owner, Redaurum, Inc., of Toronto, Ontario, expects to produce about 150,000 carats per year. Most of the production will be small, non-gem-quality material for abrasives in tools such as drill bits and rock saws.

The only other outcrop of diamond-bearing rock in the US is at Murfreesboro, Arkansas, which is a State Park where visitors can hunt for their own diamonds. Diamonds have also been found for years in the loose gravels and sediments that were deposited by glaciers, especially in the Midwest and northeastern United States. Most of these diamonds were derived from rocks somewhere in Canada, possibly beneath what is now Hudson Bay, but some may have come from sources in northern Wisconsin.

The Laramie Range rocks that contain diamonds date to the Precambrian Eon, a very ancient period of Earth history. They are from the Proterozoic Era, and these rocks are about 1,700,000,000 (1.7 billion) years old. This location is quite near the contact with an even older terrane to the north, the 2.5-billion-year-old Wyoming Province. Possibly the occurrence of diamonds is related to this contact.

Russia and South Africa produce by far most of the world's diamonds, but there is an exciting diamond exploration play in progress in northwestern Canada, which employs magnetic surveying to find the cylindrical kimberlite pipes that contain the diamonds. For more information on the Canadian diamond play, visit the Northwest Territories Diamond Page.

UPDATE: THE FIFTH LARGEST diamond found in North America was discovered at the Kelsey Lake mine in late summer, 1996. The 28.3-carat yellow stone is about three-quarters of an inch long and is valued at at least $56,000 and perhaps as much as $283,000. It is to be offered for sale in late September, 1996.

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2. Coal For Electricity

The 1995 Energy Education Report Card, prepared by the National Energy Education Development project and reported in Geotimes, shows that more than 70% of Americans DON'T KNOW that most of the electricity in the U.S. is generated by burning coal. Wyoming and Montana are among the leading coal-producing states today, but historically Pennsylvania, West Virginia, Kentucky, Illinois, and Indiana produced vast quantities. Pennsylvania Coal Map. About 57% of our electric power comes from coal, and most of the rest is from burning oil and natural gas products. The amount of electricity generated by wind, solar, nuclear, and hydroelectric plants is tiny in comparison.

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3. History's Deadliest Quake

Not exactly news...... but January 24 marks the 441st anniversary of the deadliest earthquake in recorded history. On that day in 1556, a quake at Shaanxi, in northern China, killed some 830,000 people. Quakes in this area in 1920 killed another 200,000. The fault movement that caused these quakes is a result of the collision of India with Eurasia. (Did this collision cause the Ice Ages? See Below.) Even though the zone of collision is nearly 1500 miles from Shaanxi, the effects are severe when rigid continental masses collide. In fact, effects are even being felt another 1000 miles into the continent, in southern Siberia.

Anniversaries of 30 earthquakes and volcanic eruptions are found in Dick Gibson's perpetual calendar, History of the Earth.
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4. Evidence for Oldest Sharks Discovered

Ivan Sansom (Univ. of Birmingham, England) and Paul Smith (Univ. of British Columbia) announced the discovery of 450-million-year-old shark scales at a location 30 miles southwest of Colorado Springs, Colorado. The report, in the journal Nature for Feb. 15, 1996, described late Ordovician fossil scales about one millimeter across. These probable shark scales pre-date the previous oldest evidence for sharks by 25 million years, and the fact that they are 50 million years older than the oldest known shark's teeth suggests that the animals may have been jawless fish. Sharks are among the longest-lived classes of animals. For a report on much younger shark's teeth (about 10 million years old), visit Miocene Shark's Teeth from Maryland.
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5. Vanishing Salt Flats

The Bonneville Salt Flats of western Utah are disappearing. The area is famous as the proving ground for fast vehicles -- the land speed record (633 miles per hour) was set here. Apparently the salt is eroding in the subsurface because of pumping of brines (salty, mineralized water) from nearby areas. Salt that was formerly 60" thick is now only fractions of an inch thick in places, and the race track has had to be shortened significantly. CNN News reports that Reilley Industries will begin to pump millions of gallons of salt water onto the plain to try to re-build the salt deposits. The water will evaporate during the summer months, leaving as much as 0.4" of new salt deposits each year.

The Bonneville Salt Flats are the result of evaporation of a huge lake. Lake Bonneville was filled by extreme rainfall during glacial times (most of the past 2 million years ago). Because it was in a closed basin, it had no drainage, so when the climate changed to warmer, more arid conditions, the lake simply evaporated, leaving its dissolved mineral matter (inlcuding salt) behind. The Great Salt Lake is a remnant of this huge lake, which covered an area of about 52,000 square kilometers (the Great Salt Lake extends over less than 7,000 sq km).

You can find much more information about Lake Bonneville in a paper by Roger Morrison, in the book Quaternary Non-Glacial Geology: Conterminous U.S., published by the Geological Society of America.
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6. Did the Himalayas cause the Ice Age?

A relatively new theory, proposed by Maureen Raymo of the Massachusetts Institute of Technology, suggests that the uplift of the Himalayas may have been the ultimate cause of climate change that resulted in the Ice Ages of the past 2 million years. Her studies suggest that the uplift, which was caused by the collision of India with Eurasia beginning about 40 million years ago, resulted in severe chemical weathering of the mountain uplift, which has the effect of removing carbon dioxide (CO2) from the atmosphere. The CO2 will eventually be recycled when carbonate sediments (limestone) are subducted and the volatile gas expelled, but in the short term (geological short term - a few tens of millions of years!) there may have been a reduction of the warming greenhouse effect because of less CO2 in the atmosphere. Other evidence for this idea comes from strontium isotope ratios, which suggest that there has been a serious cooling of the climate over the past 35 million years -- beginning just after the India-Eurasia collision began to uplift the Himalayas. The idea is controversial, and all scientists do not accept this concept. For more information, visit the PBS - Nova web site. The theory was featured in a recent Nova program.

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7. Feathered Dinosaurs?

The January 1997 issue of Discover Magazine reports the work of Philip Currie (Royal Tyrrell Museum, Alberta) that suggests that a dinosaur from China had feathers. The fossil, a relation of Compsognathus, is from a time about 30 million years later than Archaeopteryx, the first known bird. The implications of this discovery may be far-reaching, and much work remains to be done.