کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5783595 | 1637954 | 2017 | 52 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Relationships among physical properties as indicators of high temperature deformation or post-shock thermal annealing in ordinary chondrites
ترجمه فارسی عنوان
روابط بین خواص فیزیکی به عنوان شاخص تغییر شکل درجه حرارت بالا یا خنک کننده حرارتی پس از شوک در هندریت های معمولی
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کلمات کلیدی
کندریت، شوکه شدن، تراکم قطر بینی، ضخیم شدن سیارک ها، انلینگ،
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
ژئوشیمی و پترولوژی
چکیده انگلیسی
Collisions and attendant shock compaction must have been important for the accretion and lithification of planetesimals, including the parent bodies of chondrites, but the conditions under which these occurred are not well constrained. A simple model for the compaction of chondrites predicts that shock intensity as recorded by shock stage should be related to porosity and grain fabric. To test this model, we studied sixteen ordinary chondrites of different groups (H, L, LL) using X-ray computed microtomography (μCT) to measure porosity and metal fabric, ideal gas pycnometry and 3D laser scanning to determine porosity, and optical microscopy (OM) to determine shock stage. These included a subsample of six chondrites previously studied using transmission electron microscopy (TEM) to characterize microstructures in olivine. Combining with previous data, results support the simple model in general, but not for chondrites with low shock-porosity-foliation (low-SPF chondrites). These include Kernouvé (H6), Portales Valley (H6/7), Butsura (H6), Park (L6), GRO 85209 (L6), Estacado (H6), MIL 99301 (LL6), Spade (H6), and Queen's Mercy (H6), among others. The data for these meteorites are best explained by high ambient heat during or after shock. Low-SPF chondrites tend to have older 40Ar/39Ar ages (â¼4435-4526 Ma) than other, non-low-SPF type 6 chondrites in this study. We conclude that the H, L, and LL asteroids all were shock-compacted at an early stage while warm, with collisions occurring during metamorphic heating of the parent bodies. Results ultimately bear on whether chondrite parent bodies have internal structures more akin to a metamorphosed onion shell or metamorphosed rubble pile, and on the nature of accretion and lithification processes for planetesimals.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Geochimica et Cosmochimica Acta - Volume 203, 15 April 2017, Pages 157-174
Journal: Geochimica et Cosmochimica Acta - Volume 203, 15 April 2017, Pages 157-174
نویسندگان
Jon M. Friedrich, Alex Ruzicka, Robert J. Macke, James O. Thostenson, Rebecca A. Rudolph, Mark L. Rivers, Denton S. Ebel,