TY  - JOUR
A1  - Tkalcec, Beverley J.
A1  - Tack, Pieter
A1  - De Pauw, Ella
A1  - Vekemans, Bart
A1  - Nakamura, Tomoki
A1  - Garrevoet, Jan
A1  - Falkenberg, Gerald
A1  - Vincze, Laszlo
A1  - Brenker, Frank E.
T1  - Sr distribution as proxy for Ca distribution at depth in SXRF analysis of mm-sized carbonaceous chondrites: Implications for asteroid sample return missions
T2  - Meteoritics & planetary science
N2  - 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.
Y1  - 2022
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/75646
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-756461
SN  - 1945-5100
N1  - 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.
N1  - Open access funding enabled and organized by Projekt DEAL. This work was supported by JSPS KAKENHI Grant Number 20H00188 to TN.
N1  - 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.
VL  - 57
IS  - 4
SP  - 817
EP  - 829
PB  - Wiley-Blackwell
CY  - Hoboken, NJ
ER  -