MADISON -- Nacre -- or mother of pearl, scientists and artisans know, is one of nature's amazing utilitarian materials.
Produced by a multitude of mollusk species, nacre is widely used in jewelry and art. It is inlaid into musical instruments, furniture and decorative boxes. Fashioned into buttons, beads and a host of functional objects from pens to flatware, mother of pearl lends a lustrous iridescence to everyday objects.
In recent years, subjecting the material to the modern tools of scientific analysis, scientists have divined the fine points of nacre architecture and developed models to help explain its astonishing durability: 3,000 times more fracture resistant than the mineral from which it is made, aragonite.
Now, in a new report (Thursday, Feb. 16) in the Journal of the American Chemical Society (JACS), scientists from the University of Wisconsin-Madison show that nacre can also be deployed in the interest of science as a hard-wired thermometer and pressure sensor, revealing both the temperature and ocean depth at which the material formed.
"We found a strong correlation between the temperature at which nacre was deposited during the life of the mollusk and water temperature," explains Pupa Gilbert, a UW-Madison professor of physics and chemistry and the senior author of the new JACS report. "All other (temperature) proxies are based on chemical analyses and the relative concentration of different elements or isotopes. This could be our first physical proxy, in which the microscopic structure of the material tells us the maximum temperature and maximum pressure at which the mollusk lived."
The new study was conducted using mother of pearl from modern mollusks, but Gilbert notes that nacre is widespread in the fossil record going back 450 million years. If the techniques used by the Wisconsin group can be applied to fossil nacre, scientists can begin to accurately reconstruct a global record of anc
|Contact: Pupa Gilbert |
University of Wisconsin-Madison