Assessment of Cluster Chondrite Accretion Temperature Using Electron Backscatter Diffraction and Implications for Chondrule Formation Models

Goudy, S. P.

doi:10.15760/etd.7141

Cited by 1 publication

(16 citation statements)

References 83 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Example subregions of the EBSD maps of Forest Vale and Quenggouk are shown in Figures 2 and 3. Figure 4 displays equally sized subsections from the centers of EBSD GOS maps for all samples as well as two reference samples, Kernouvé (Ruzicka & Hugo, 2018) and Tieschitz (Goudy, 2019). Figure 5 displays CRA stereonets for all sample meteorites.…”

Section: Resultsmentioning

confidence: 99%

“…Figure 5 displays CRA stereonets for all sample meteorites. Figure 6 displays the GOS standard deviation values of our samples alongside those of reference samples from the literature (Goudy, 2019; Hugo et al., 2019; Ruzicka et al., 2020; Ruzicka & Hugo, 2018). Grain reference orientation deviation (GROD) maps for the olivine grains of the samples are provided in the online supplement, all on a 0°–20° color scale.…”

Section: Resultsmentioning

confidence: 99%

“…The concept of accretional deformation is primarily argued for on the basis of textural observations such as mutual deformation between chondrules and surrounding objects, close-fit cluster chondrite textures, and in one case, a "burst" chondrule (i.e., Hutchison, 1996;Metzler, 2012), but the research existing on the topic is scarce, and so requires further work to validate or refute. Previously studied type 3 S1 ordinary chondrites with accretion-associated deformation signatures, a "squashing" of chondrules and their mineral grains, characterized by cluster chondrite textures (~90 vol% chondrules; Metzler, 2012), fall into a wide range of GOS skews, but only a narrow range of f <010> + f <001> parameters: 0.592-0.640 (Goudy, 2019). Notably, Sena has an f <010> + f <001> parameter of 0.585, which potentially indicates accretional deformation as a source for its observed deformation rather than shock metamorphism.…”

Section: Shock Metamorphism Versus Accretional Deformationmentioning

confidence: 99%

“…To further investigate the thermal and impact histories of the H4 chondrite samples, we employ a microstructural approach to complement the existing cooling rate data of H4 chondrites. By using electron backscatter diffraction (EBSD) to examine dislocation activity in sample olivine, we can infer the temperature regime at which deformation occurred (Goudy, 2019; Hugo et al., 2019; Ruzicka & Hugo, 2018). By the same olivine dislocation observations, we can also assess postdeformational annealing, which imposes additional temperature constraints on the sample following its deformation (Goudy, 2019; Hugo et al., 2019; Ruzicka & Hugo, 2018).…”

Section: Introductionmentioning

confidence: 99%

“…By using electron backscatter diffraction (EBSD) to examine dislocation activity in sample olivine, we can infer the temperature regime at which deformation occurred (Goudy, 2019; Hugo et al., 2019; Ruzicka & Hugo, 2018). By the same olivine dislocation observations, we can also assess postdeformational annealing, which imposes additional temperature constraints on the sample following its deformation (Goudy, 2019; Hugo et al., 2019; Ruzicka & Hugo, 2018). Through this approach, we can infer if each of our samples was impact‐shocked, at what temperature regime that shock occurred, and if they remained buried to cool slowly at depth or were excavated to cool quickly on or near the surface of their parent body.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Evidence for multiple early impacts on the H chondrite parent body from electron backscatter diffraction analysis

Goudy

Chapman

2023

Meteorit & Planetary Scien

View full text Add to dashboard Cite

We examined H4 chondrites Beaver Creek, Forest Vale, Quenggouk, Ste. Marguerite, and Sena with the electron backscatter diffraction (EBSD) techniques of Ruzicka and Hugo (2018) to determine if there is evidence for shock metamorphism consistent with the previously inferred histories of their early impact excavation or lack thereof. We find that all samples have EBSD data consistent with a history of synmetamorphic impact shock (i.e., shock during thermal metamorphism), followed by postshock annealing. Petrographic analysis of Sena, Quenggouk, and Ste. Marguerite found exsolved Cu and irregular troilite within Fe metal, features consistent with shock metamorphism. All samples have a spatial variability in grain deformation consistent with shock processes, though Forest Vale, Quenggouk, and Ste. Marguerite may have relict signatures of accretional deformation as indicated by variability in their olivine deformation metrics. Within the context of previous workers' geochemical observations, a more complex history is inferred for each sample. The "slow-cooled" samples, Quenggouk and Sena, were subject to synmetamorphic shock without excavation and annealed at depth. The same is true of the "fast-cooled" samples, Beaver Creek, Forest Vale, and Ste. Marguerite. However, after annealing, these rocks were excavated by a secondary impact or impacts around 5.2-6.5 Ma post-CAI formation and were left to cool rapidly on the surface of the H chondrite parent body. These interpreted histories are best compatible with a model of an impact-battered but intact onion shell for the earliest history of the H parent body. However, the EBSD evidence does not preclude a parent body disruption after 7 Ma post-CAI formation.

show abstract

Section: Resultsmentioning

confidence: 99%