TY - JOUR
T1 - Volume and surface-area measurements using tomography, with an example from the Brenham pallasite meteorite
AU - Spinsby, Jacob
AU - Friedrich, Heiner
AU - Buseck, P R
N1 - Funding Information:
This paper describes work carried out at the Arizona State University under Grant EAR-0440388 from the NSF Earth Sciences Division and NNG06GF08G from the NASA Cosmochemistry Program. We thank Steven A. Gordon and the Software Factory for their programming help, Gary Scott for his work in preparing the Brenham sections and photographs many years ago, and Laura van Poppel for her work in calibrating and testing ETSAV and ETCut.
PY - 2008/1
Y1 - 2008/1
N2 - Increased computer speed has helped to proliferate tomography throughout the geosciences. Although best known from the medical CATscan, tomography is also a powerful tool for geological problems. Whereas qualitative tomography is widely used, quantitative data from tomograms are not so commonly available. Presented here are two programs, Electron Tomography Segmentation, surface Area, and Volume (ETSAV) and Electron Tomography CUTter (ETCut), that were written to obtain quantitative volume and surface-area data from tomograms. Based on a specified threshold value, ETSAV distinguishes objects within a tomogram and then returns volume and surface-area data for each object. If object separation is unsatisfactory using a single threshold, ETCut is called to digitally separate objects that appear connected in the tomogram, allowing ETSAV to perform its functions. By knowing the nature of the object of interest, error can be corrected to, on average, less than 5% for a single object; combined volumes of many particles of different sizes may result in lesser errors. A section of the Brenham pallasite meteorite was examined using the programs. Olivine comprises 67.2% of the volume (50.4% wt%), followed by FeNi metal at 23.1% (39.3% wt%), troilite at 4.4% (4.8% wt%), and schreibersite at 3.4% (5.5% wt%). In all, 56.1% and 44.7% of the troilite and schreibersite surface areas, respectively, border olivine, suggesting that they wet olivine. Since the programs can be applied to any tomogram, from any field, there are many potential applications.
AB - Increased computer speed has helped to proliferate tomography throughout the geosciences. Although best known from the medical CATscan, tomography is also a powerful tool for geological problems. Whereas qualitative tomography is widely used, quantitative data from tomograms are not so commonly available. Presented here are two programs, Electron Tomography Segmentation, surface Area, and Volume (ETSAV) and Electron Tomography CUTter (ETCut), that were written to obtain quantitative volume and surface-area data from tomograms. Based on a specified threshold value, ETSAV distinguishes objects within a tomogram and then returns volume and surface-area data for each object. If object separation is unsatisfactory using a single threshold, ETCut is called to digitally separate objects that appear connected in the tomogram, allowing ETSAV to perform its functions. By knowing the nature of the object of interest, error can be corrected to, on average, less than 5% for a single object; combined volumes of many particles of different sizes may result in lesser errors. A section of the Brenham pallasite meteorite was examined using the programs. Olivine comprises 67.2% of the volume (50.4% wt%), followed by FeNi metal at 23.1% (39.3% wt%), troilite at 4.4% (4.8% wt%), and schreibersite at 3.4% (5.5% wt%). In all, 56.1% and 44.7% of the troilite and schreibersite surface areas, respectively, border olivine, suggesting that they wet olivine. Since the programs can be applied to any tomogram, from any field, there are many potential applications.
KW - Brenham pallasite
KW - Fractal particles
KW - Quantitative tomography
KW - Segmentation
KW - Tomogram surface area
KW - Tomogram volume
KW - Tomography
UR - http://www.scopus.com/inward/record.url?scp=35748947735&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=35748947735&partnerID=8YFLogxK
U2 - 10.1016/j.cageo.2007.01.008
DO - 10.1016/j.cageo.2007.01.008
M3 - Article
AN - SCOPUS:35748947735
SN - 0098-3004
VL - 34
SP - 1
EP - 7
JO - Computers and Geosciences
JF - Computers and Geosciences
IS - 1
ER -