Smithsonian Science » rocks & minerals

Following in the footsteps of James Smithson

John Barrat — Thu, 18 Aug 2011 13:04:22 +0000

Inveraray Castle in Argyllshire, Scotland, was one of the places visited by James Smithson (1764–1829), geologist and founder of the Smithsonian Institution, during the summer of 1784 while he was traveling on a scientific expedition to the remote island of Staffa on Scotland’s Northwest coast. Steven Turner, Division of Medicine and Science curator at the Smithsonian’s National Museum of American History, recently retraced Smithson’s journey to Staffa and wrote about it in an interesting post “Following in the footsteps of James Smithson,” on the American History Museum blog “O say can you see?”

500 carats of rough diamonds donated to Natural History Museum

John Barrat — Wed, 17 Aug 2011 16:58:43 +0000

More than 500 carats of rough diamonds were recently donated to the Department of Mineral Sciences of the Smithsonian’s Natural History Museum by Jewlers Mutual Insurance Co. of Neenah, Wis. Although rough diamonds have a limited market value, their value to the museum for research and display is considerable. This donation in particular is unusual in that each diamond in the group is labeled with the location of where it was mined.

Images right and below: Rough diamonds

“It’s very rare to know where some rough diamonds came from because typically, once they come out of the mine, they go to market and are sold,” says Jeffry Post, curator in the Department of Mineral Sciences. “In most cases, diamonds lose any documentary links to their source by the time they reach the market.” This donation will be a great asset to researchers, allowing them to study specimens and knowing where they originated in the Earth.

The larger diamonds in the Jewelers Mutual donation will be added to the diamond exhibition in the Natural History Museum’s Gem and Mineral Hall. The others will be made available for scientific study. Jewelers Mutual originally acquired the diamonds to display in the company’s onsite gallery of gems and minerals in Neenah.

Gale Crater to be landing site for NASA’s Mars Science Laboratory

John Barrat — Fri, 22 Jul 2011 16:29:12 +0000

During a press conference Friday, July 22 at the Smithsonian’s National Air and Space Museum, NASA announced that Gale Crater will be the landing site for the Mars Science Laboratory. Scheduled to launch in late 2011 and arrive at Mars in August 2012, the Mars Science Laboratory is a rover that will assess the planet’s “habitability”—if it ever was, or is today, an environment able to support microbial life.

“Having the right instruments and knowing where to go are equally important,” said John Grant, a Smithsonian geologist and co-chair of the landing site steering committee. “We looked for a site that has water associated with it, materials of interest that are concentrated and preserved and that is accessible so we can get to it. Gale Crater is a good place to explore because there is a mountain of layered materials rising from its floor. Much like chapters in a book, the sediments, minerals and layers in this stack record the story about what Mars was like in the past. The rover will investigate where sediments forming the layers came from and explore how the layers relate to the environments in which they formed.” Grant, who is a researcher in the Center for Earth and Planetary Studies, is also a member of the science team for Mars rovers Spirit and Opportunity.

Image right: Gale Crater is 96 miles in diameter and holds a layered mountain rising about 3 miles above the crater floor. The portion of the crater within the planned landing area north of the mountain has an alluvial fan likely formed by water-carried sediments. The lower layers of the nearby mountain–within driving distance for Curiosity–contain minerals indicating a wet history. (Image NASA/JPL-Caltech/ASU)

The car-sized Mars Science Laboratory, or Curiosity, is scheduled to launch late this year and land in August 2012. The target crater is 96 miles in diameter and holds a mountain rising higher from the crater floor than Mount Rainier rises above Seattle. Gale is about the combined area of Connecticut and Rhode Island. Layering in the mound suggests it is the surviving remnant of an extensive sequence of deposits.

Image left: This artist concept shows NASA’s Mars Science Laboratory Curiosity rover, a mobile robot for investigating Mars’ past or present ability to sustain microbial life. In this picture, the rover examines a rock on Mars with a set of tools at the end of the rover’s arm, which extends about 7 feet. (Image NASA/JPL-Caltech)

During a prime mission lasting one Martian year—nearly two Earth years—researchers will use the rover’s tools to study whether the landing region had favorable environmental conditions for supporting microbial life and for preserving clues about whether life ever existed.

In 2006, more than 100 scientists began to consider about 30 potential landing sites during worldwide workshops. Four candidates were selected in 2008. An abundance of targeted images enabled thorough analysis of the safety concerns and scientific attractions of each site. A team of senior NASA science officials then conducted a detailed review and unanimously agreed to move forward with the MSL Science Team’s recommendation. The team is comprised of a host of principal and co-investigators on the project.

NASA Video: Animation of the Mars Science Laboratory from entry, descent and landing phase to surface operation.

Curiosity is about twice as long and more than five times as heavy as any previous Mars rover. Its 10 science instruments include two for ingesting and analyzing samples of powdered rock that the rover’s robotic arm collects. A radioisotope power source will provide heat and electric power to the rover. A rocket-powered sky crane suspending Curiosity on tethers will lower the rover directly to the Martian surface.

The rover and other spacecraft components are being assembled and are undergoing final testing. The mission is targeted to launch from Cape Canaveral Air Force Station in Florida between Nov. 25 and Dec. 18. NASA’s Jet Propulsion Laboratory in Pasadena manages the mission for the agency’s Science Mission Directorate in Washington. JPL is a division of Caltech.

Pink tourmaline “Nautilus” pendant enters National Gem Collection

John Barrat — Mon, 23 May 2011 15:02:51 +0000

The Smithsonian’s National Gem Collection in the Department of Mineral Sciences of the Smithsonian’s National Museum of Natural History, recently added the “Nautilus” pendant to its collection as the gift of Thomas Dailing. The pendant, designed by Dailing, took Grand Prize in the National Saul Bell Design Competition in 2008. It features a beautiful 3.76-ct pink tourmaline from Nigeria. The 18k yellow gold pendant involves a spiral based on Descartes’ equiangular spiral, a parabolic dish, and a truncated cone made of spiraling white gold wires. This pendant blends reflection and form together to create the effect of the inside of a chambered nautilus shell. It is centered with a “Phantom Spinner” tourmaline, a new cut by Richard Homer. The tourmaline has a polished drill hole running through its axis, allowing a tube set diamond to rest on its center, with no visible connection. The intense pink color of the tourmaline is magnified and reflected throughout the pendant due to this ingenuous design.

Smithsonian hydrologist discovers that rainfall has dried up Panama’s drinking water

John Barrat — Tue, 17 May 2011 13:14:56 +0000

To understand the long-term effects of a prolonged tropical storm in the Panama Canal watershed, Robert Stallard, staff scientist at the Smithsonian Tropical Research Institute and research hydrologist at the U.S. Geological Survey, and Armando Ubeda, the LightHawk Mesoamerica program manager, organized four flights over the watershed to create a digital map of landslide scars.

Two feet of heavy rain inundated the Panama Canal watershed between Dec. 7 and 10, 2010. Landslides tore down steep slopes, choking rivers with sediment and overwhelming Panama City’s water-treatment plant. Flooding closed the Panama Canal for the first time since 1935. Despite the deluge, the influx of sediments in the water forced authorities to shut down the plant, leaving a million residents of central Panama without clean drinking water for nearly a month.

Image left: Storms trigger landslides that release sediment into rivers and streams (Photo by Robert Stallard)

LightHawk, a conservation organization based in the U.S., donates flights for research and conservation efforts. Retired United Airlines captain David Cole flew the Cessna 206 aircraft, and the four flights yielded images of 191 square miles (495 square kilometers) of watershed. Stallard observed numerous new landslide scars left behind by the December storm, supporting his prediction that landslides supplied much of the suspended sediment that disrupted Panama’s water supply.

The new watershed erosion map will allow Stallard and collaborators from the Panama Canal Authority to calculate the landslide risk of future storms and direct strategies to minimize the effect on Panama’s water supply.

Tropical hydrologists agree that river-borne sediment originates from surface erosion or from deep erosion from landslides. In 1985, Stallard predicted that “deep erosion, not shallow surface erosion, is the primary process controlling the chemistry and sediment levels in many tropical rivers that pass through mountainous areas.” Few studies have been conducted to test this prediction.

Image right: Robert Stallard, STRI staff scientist and USGS hydrologist. (Photo by Marcos Guerra)

Deforestation of steep slopes is the primary factor determining the number of landslides. Six decades of aerial photographs analyzed by USGS researchers in similar landscapes in Puerto Rico showed that landslide frequency doubles outside protected nature preserves, and that roads and infrastructure make landslides eight times more likely. Although landslides happen in natural forests, the objective is to limit their impact through appropriate land-use practices.

“With development, landslide intensity increases dramatically,” said Stallard. “In its history, the Panama Canal watershed has experienced huge floods. It’s still hard to say whether future floods will be accompanied by disastrous landslides like those produced by Hurricane Mitch in Central America.” In 1998, Hurricane Mitch swept across Honduras, Guatemala, Nicaragua and El Salvador causing more than 10,000 deaths and incalculable economic damage. Panama’s proximity to the equator puts the country outside the usual hurricane zone, but prolonged tropical storms may occur.

Erosion control is possible. Partnering with the Panama Canal Authority and Panama’s Environmental Authority, the Smithsonian is conducting a 700 hectare experiment in the canal watershed funded by the HSBC Climate Partnership to compare the effects of land-use choices, such as cattle ranching or reforestation with native tree species on water supply, carbon storage and biodiversity. Stallard hopes that this research will provide new information about which land uses provide a steady supply of clean water for the Canal.

With the first rains in May, the eight-month wet season begins anew in central Panama. Drinking water flows freely, the rivers are clear and the Panama Canal is open for business. But bare slopes of past landslides continue to create secondary erosion, which will dislodge sediments from the steep, rainy and rugged Panama Canal watershed in 2011. The long-term effects of the 2010 storm may continue as renewed interruptions in the water supply in 2011.–Beth King

Video: On the hunt for 251-million-year-old insects in South Africa

John Barrat — Tue, 19 Apr 2011 01:55:27 +0000

Paleoecologist Conrad Labandeira travels to the Karoo Basin of South Africa to find leaf fossils from the Permian-Triassic boundary, the time of the Earth's largest mass extinction. What can bug bites on leaves tell us about our own uncertain times? Related posts:

A new perspective on the Solar System with Planetary Geologist Jim Zimbelman

John Barrat — Wed, 09 Mar 2011 06:14:14 +0000

Yowah Nut Opal

John Barrat — Wed, 19 Jan 2011 16:17:35 +0000

This Yowah Nut Opal comes from Queensland, Australia and consists of precious opal deposits enclosed in an ironstone nodule. A recent gift to the Smithsonian’s National Gem Collection from the Richard Ashley Foundation, the play-of-color in this opal is spectacular, with flashes of red, orange, yellow, green, blue and purple. For a full description, visit the National Gem Collection Website. (Photo by Ken Larson)

Hope Diamond: Embracing Hope

John Barrat — Mon, 22 Nov 2010 17:57:32 +0000

The Hope Diamond, the world’s most famous diamond, is on display at the Smithsonian’s National Museum of Natural History in a new temporary setting, “Embracing Hope.” The new setting was designed by Harry Winston Inc., and unveiled and placed on public display on Thursday, Nov. 18. The event marks the 50th anniversary of the Hope Diamond’s donation to the museum in 1958 and the 100th anniversary of the museum. Shown here with the Hope Diamond is National Museum of Natural History Curator Jeffery Post. To learn more about the Hope Diamond see its Smithsonian Web page by clicking this LINK. (Photo by Jim Diloreto)

Fossil reveals 48-million year history of zombie ants

John Barrat — Wed, 10 Nov 2010 12:42:43 +0000

A 48 million-year-old fossilized leaf has revealed the oldest known evidence of a macabre part of nature – parasites taking control of their hosts to turn them into zombies.

The discovery has been made by a research team led by David Hughes of the University of Exeter in England, who studies parasites that can take over the minds of their hosts; Conrad Labandeira from the Smithsonian’s National Museum of Natural History; and Torsten Wappler, from the Steinmann Institute in Germany.

Image right: An ant killed by a fungal parasite is shown here biting into a leaf vein. The fungal growth can be clearly seen issuing from the ant’s head. (Photo by David P. Hughes)

All manner of animals are susceptible to the often deadly body invasion, but scientists have been trying to track down when and where such parasites evolved.

“There are various techniques, called a molecular clock approach, which we can use to estimate where and when they developed and fossils are an important source of information to calibrate such clocks,” Hughes says.

“This leaf shows clear signs of one well documented form of zombie-parasite, a fungus which infects ants and then manipulates their behavior.”

The fungus, called Ophiocordyceps unilateralis, appears to take over the mind of infected ants – causing them to leave their colonies and head for a leaf which provides the ideal conditions for the parasite to reproduce.

Image left and below: This 48-million-year-old leaf fossil from Messel clearly bears the tell-tale scars of ants that have been infected with the mind-controlling fungal parasite. (Photo by Torsten Wappler)

When the ant gets there it goes into a ‘death grip’– biting down very hard on the major vein of a leaf. This means that when the ant dies, its body stays put so the fungus has time to grow and release its spores to infect other ants.

The death grip bite leaves a very distinct scar on the leaves. This prompted Hughes, Labandeira and Wappler to search for potential evidence of the fungus at work by studying the fossilized remains of leaves.

After studying leaf fossils from the Messel Pit, a site on the eastern side of the Rhine Rift Valley in Hesse, Germany, they found clear evidence of the death grip bite in a 48 million-year-old leaf specimen.

“The evidence we found mirrors very closely the type of leaf scars that we find today, showing that the parasite has been working in the same way for a very long time,” Hughes explains.

“This is, as far as we know, the oldest evidence of parasites manipulating the behaviour of their hosts and it shows this parasitic association with ants is relatively ancient and not a recent development.

“Hopefully we can now find more fossilised evidence of parasitic manipulation. This will help us shed further light on the origins of this association so we can get a better idea of how it has evolved and spread.”

The paper, Ancient death-grip leaf scars reveal ant-fungal parasitism, was published in a recent edition of Royal Society journal Biology Letters. –Research News, University of Exeter