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Complete Tem-Tomography: 3D Structure of Gems ClusterGEMS (glass with embedded metal and sulfide) grains in interplanetary dust particles (IDPs) are considered to be one of the ubiquitous and fundamental building blocks of solids in the Solar System. They have been considered to be interstellar silicate dust that survived various metamorphism or alteration processes in the protoplanetary disk but the elemental and isotopic composition measurements suggest that most of them have been formed in the protoplanetary disk as condensates from high temperature gas. This formation model is also supported by the formation of GEMS-like grains with respect to the size, mineral assemblage, texture and infrared spectrum by condensation experiments from mean GEMS composition materials. Previous GEMS studies were performed only with 2D observation by transmission electron microscopy (TEM) or scanning TEM (STEM). However, the 3D shape and structure of GEMS grains and the spatial distribution of Fe/FeS's has critical information about their formation and origin. Recently, the 3D structure of GEMS grains in ultrathin sections of cluster IDPs was revealed by electron tomography using a TEM/STEM (JEM-2100F, JEOL). However, CT images of thin sections mounted on Cu grids acquired by conventional TEM-tomography are limited to low tilt angles (e. g., less than absolute value of 75 deg. In fact, previous 3D TEM observations of GEMS were affected by some artifacts related to the limited tilt range in the TEM used. Complete tomographic images should be acquired by rotating the sample tilt angle over a range of more than absolute value of 80 deg otherwise the CT images lose their correct structures. In order to constrain the origin and formation process of GEMS grains more clearly, we performed complete electron tomography for GEMS grains. Here we report the sample preparation method we have developed for this study, and the preliminary results.
Document ID
20150002980
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Matsuno, J.
(Kyoto Univ. Kyoto, Japan)
Miyake, A.
(Kyoto Univ. Kyoto, Japan)
Tsuchiyama, A.
(Kyoto Univ. Kyoto, Japan)
Messenger, S.
(NASA Johnson Space Center Houston, TX, United States)
Nakamura-Messenger, K.
(NASA Johnson Space Center Houston, TX, United States)
Date Acquired
March 16, 2015
Publication Date
March 16, 2015
Subject Category
Astrophysics
Report/Patent Number
JSC-CN-32847
Meeting Information
Meeting: Lunar and Planetary Science Conference
Location: The Woodlands, TX
Country: United States
Start Date: March 16, 2015
End Date: March 20, 2015
Sponsors: Universities Space Research Association, Lunar and Planetary Inst.
Distribution Limits
Public
Copyright
Public Use Permitted.
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