Abstract/Details

Studies of high pressure and high temperature physical properties of liquid iron sulfide and gallium using synchrotron x-ray


2009 2009

Other formats: Order a copy

Abstract (summary)

The interior of the earth has always been of great interest to geoscientists. Due to the inaccessibility of samples from deep earth, we have been relying upon other scientific methods and procedures to explore the earth’s interior. Cosmochemical and geochemical studies of samples from shallow earth suggest that the core is mainly consisted of Fe, Ni, and one or more lighter elements. Previous investigations from seismic data and mineral physics data indicate that the outer core’s density is about 6% to 10% less than that of pure Fe at the outer core’s pressure and temperature conditions, and thus there must be a significant amount of a light element or various kinds of light elements existing in the outer core. The light element candidates in the outer core include C, H, O, S, Si, and the caused density variation might play a critical role in the liquid outer core convection. Using the x-ray absorption radiograph system, we have successfully measured the density of liquid phase FeS at 1673K and up to 5.6GPa in pressure. Our self-developed absorption image fitting program has proved to be reliable in determining the density of liquid FeS. The 15.4 GPa isothermal bulk modulus of liquid FeS at 1673K derived from the density compression curve provides information in constraining the sulfur content in the liquid outer core, which is one of the strong light element candidates that might be responsible for the density deficit in the outer core. To further understand the liquid behavior under extreme condition, we used the pair distribution function (PDF) method to study the structure of an elemental liquid—gallium and its atomic structure change due to compression. Diffuse scattering data were collected over the whole pressure range of liquid state (0.1-2GPa) at ambient temperature. The PDF results show that the first nearest neighbor peak position did not change with pressure increasing, while the farther peaks positions in the intermediate distance range decreased with pressure increasing. This leads to a conclusion of the possible existence of “locally rigid units” in the liquid. With the addition of a series of reverse Monte Carlo modeling of the liquid structure, we have observed that the coordination number in the local rigid unit increases with pressure. The bulk modulus of liquid gallium derived from the volume compression curve at ambient temperature is 12.1(6) GPa.

Indexing (details)


Subject
Geophysics
Classification
0373: Geophysics
Identifier / keyword
Earth sciences; Convection; Gallium; Iron sulfide; Outer core
Title
Studies of high pressure and high temperature physical properties of liquid iron sulfide and gallium using synchrotron x-ray
Author
Yu, Tony
Number of pages
103
Publication year
2009
Degree date
2009
School code
0771
Source
DAI-B 71/02, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9781109615296
Advisor
Chen, Jiuhua
University/institution
State University of New York at Stony Brook
University location
United States -- New York
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3393676
ProQuest document ID
305102374
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/305102374
Access the complete full text

You can get the full text of this document if it is part of your institution's ProQuest subscription.

Try one of the following:

  • Connect to ProQuest through your library network and search for the document from there.
  • Request the document from your library.
  • Go to the ProQuest login page and enter a ProQuest or My Research username / password.