Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Geologists map Cartwright country


’Big Bonanza’ and the Comstock Lode

Remember the burning Ponderosa map at the beginning of the long-running TV show "Bonanza"? It’s up in flames before you can read all the place names.
Now a geologist at Washington University in St. Louis has replaced that map with one of the famous ore site known as the Comstock Lode, a part of which is the "Big Bonanza."

While it’s doubtful that Hoss, Adam and Little Joe – not to mention the sages, Pa and Hop Sing – could make heads nor tails of it, the map is a valuable contribution to geology because it gives an interpretation of the flow of hot waters interacting with rock some 14 million years ago that created the ore district. Between 1859 and 1882, the Comstock Lode produced gold and silver in such quantities that the bullion would be worth several billion dollars in today’s markets.

Robert Criss, Ph.D., professor of earth and planetary sciences in Arts & Sciences, and his former graduate student Michael J. Singleton, Ph.D., now at Lawrence Berkeley National Laboratory, analyzed 327 rock samples collected from a portion of the Comstock Lode as well as historical samples and ones from the Smithsonian Institute and "visualized" a kind of symmetrical flow. They were able to determine the flow thanks to a mathematical technique called kriging that allows computer contouring of oxygen isotope data gleaned from the rock samples.

When water and rock interact in ore deposition they exchange isotopes. Isotopes are different variations of the same element. There are three oxygen isotopes, oxygen-16, -17 and -18. All three behave chemically as oxygen, differing only in their mass. Most is oxygen-16, but about one oxygen atom in 500 is oxygen-18, and only one in about 2,500 is oxygen-17. Rocks are about 50 percent oxygen by weight, water 90 percent. The exchange of isotopes – the researchers measured O-16 and O-18– creates "patterns of disturbance" in the rock, which the researchers can map by combining a lot of field work with lab analysis and computing.

"We can map and interpret these patterns long after the disturbance happened -– 12 to 14 million years ago" said Criss. " The rocks preserve a record of what happened."

Criss said the hydrothermal flow geometry that created the ore district was a longitudinal roll pattern superimposed on a unicellular flow system. Think of the longitudinal rolls as two parallel tubes and the unicellular system as a flat roll. The map is the first evidence showing the longitudinal roll pattern occurring in nature. The system had been predicted by theory but never seen before in an ore district.

"We’ve shown that these modes of convection can occur on Earth under the right circumstances," Criss said. "It’s the first description of such symmetry in an ore district. The ore body positions have an obvious relationship to these rolls. "

The research was published in the April issue of the Journal of Geophysical Research. It was supported by funding from the National Science Foundation.

The finding is important for geologists to understand the creation of ore deposits. These events occur underground and must be analyzed remotely. And it could have economic implications.

"It’s possible, under perfect conditions, to understand currents of fluid that make ore bodies," Criss said. "If this could become part of a predictive tool to locate currents that form ore bodies, that would be a valuable outcome because we don’t have very good theories on how ore bodies are formed. It’s a very peculiar process."

Tony Fitzpatrick | EurekAlert!
Further information:

More articles from Earth Sciences:

nachricht Receding glaciers in Bolivia leave communities at risk
20.10.2016 | European Geosciences Union

nachricht UM researchers study vast carbon residue of ocean life
19.10.2016 | University of Miami Rosenstiel School of Marine & Atmospheric Science

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>