Sr distribution as proxy for Ca distribution at depth in SXRF analysis of mm-sized carbonaceous chondrites: Implications for asteroid sample return missions

  • Reliable identification of chondrules, calcium-aluminum-rich inclusions (CAIs), carbonate grains, and Ca-phosphate grains at depth within untouched, unprepared chondritic samples by a nondestructive analytical method, such as synchrotron X-ray fluorescence (SXRF) computed tomography (CT), is an essential first step before intrusive analytical and sample preparation methods are performed. The detection of a local Ca-enrichment could indicate the presence of such a component, all of which contain Ca as major element and/or Ca-bearing minerals, allowing it to be precisely located at depth within a sample. However, the depth limitation from which Ca-K fluorescence can travel through a chondrite sample (e.g., ∼115 µm through material of 1.5 g cm−3) to XRF detectors leaves many Ca-bearing components undetected at deeper depths. In comparison, Sr-K lines travel much greater distances (∼1700 µm) through the same sample density and are, thus, detected from much greater depths. Here, we demonstrate a clear, positive, and preferential correlation between Ca and Sr and conclude that Sr-detection can be used as proxy for the presence of Ca (and, thus, Ca-bearing components) throughout mm-sized samples of carbonaceous chondritic material. This has valuable implications, especially for sample return missions from carbonaceous C-type asteroids, such as Ryugu or Bennu. Reliable localization, identification, and targeted analysis by SXRF of Ca-bearing chondrules, CAIs, and carbonates at depth within untouched, unprepared samples in the initial stages of a multianalysis investigation insures the valuable information they hold of pre- and post-accretion processes in the early solar system is neither corrupted nor destroyed in subsequent processing and analyses.
Metadaten
Author:Beverley J. TkalcecORCiDGND, Pieter TackORCiD, Ella De PauwORCiD, Bart Vekemans, Tomoki NakamuraORCiD, Jan GarrevoetGND, Gerald FalkenbergORCiDGND, Laszlo VinczeORCiD, Frank E. BrenkerORCiDGND
URN:urn:nbn:de:hebis:30:3-756461
DOI:https://doi.org/10.1111/maps.13797
ISSN:1945-5100
Parent Title (English):Meteoritics & planetary science
Publisher:Wiley-Blackwell
Place of publication:Hoboken, NJ
Document Type:Article
Language:English
Date of Publication (online):2022/03/02
Date of first Publication:2022/03/02
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2023/09/15
Volume:57
Issue:4
Page Number:13
First Page:817
Last Page:829
Note:
This research was supported in part by the special research fund of Ghent University under project number BOF17-GOA-015 (B.V.) and by the FWO Research Projects G0D5221N and G099817N.
Note:
Open access funding enabled and organized by Projekt DEAL. This work was supported by JSPS KAKENHI Grant Number 20H00188 to TN.
Note:
The research leading to this result has been supported by the project CALIPSOplus under the Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020.
HeBIS-PPN:514235829
Institutes:Geowissenschaften / Geographie
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 55 Geowissenschaften, Geologie / 550 Geowissenschaften
Sammlungen:Universitätspublikationen
Licence (German):License LogoCreative Commons - CC BY - Namensnennung 4.0 International