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Chondrule formation in the early Solar System

a combined ICP-MS, ICP-OES and petrological study

Diese Arbeit untersucht die Formation und Entwicklung von Chondrulen und die nötigen analytischen Werkzeuge und Methoden für diese Art von Untersuchung. Eine Kombination aus Frost-Tauwechsel, „Table-Top“ Aufschlüssen individueller Chondrulen und Analyse mittels ICP-MS und -OES von kleinen Proben (Durchschnitt ~1 mg) ist entwickelt und getestet worden. Die chemische Identifikation von ganzen Chondrulen wird untersucht und die beobachteten Gruppierungen mit klassischen Einzelmineralphasen Klassifikationsschemen verglichen. Die Evolution der Chondrulenarten eines Chondrites, ihre Beziehung zu dessen Zusammensetzung und zu ähnlichen Chondrulen in anderen Chondritarten werden diskutiert. Die Datei werden mit bekannten Daten für das Sonnensystem, CI- und OC-Meteoriten und CAI (Calcium-Aluminium-rich Inclusions) verglichen. Die wahrscheinliche Herkunft von Ausgangsmaterialien und Formationsprozessen werden unter die Lupe genommen. Zum Schluss wird eine Zeitspanne und Formationsumgebung für die untersuchten Objekte vorgeschlagen.  

This work looks at the formation and evolution of chondrules and the analytical tools necessary for such an investigation. A combination of freeze-thaw disaggregation, table-top digestion of individual chondrules and ICP-MS and -OES measurements of trace and major elements were tested for applicability to such small samples (average ~1 mg). Chemical fingerprinting of individual whole chondrules is investigated and the observed distinctions compared to classical single mineral phase classification. The data are used to evaluate the evolution of different chondrule types within a chondrite, their relationship to similar chondrules in other meteorites and the ties between chondrules and the bulk meteorite. The data are compared to available values for the Solar System, CI-chondrites, OC-chondrules and CAI. Chondrule source material and the processes operating in the chondrule formation region are evaluated. Finally a nebular vs. planetary formation setting, likely formation mechanisms and timeframes are assigned.

Titel: Chondrule formation in the early Solar System
Untertitel: a combined ICP-MS, ICP-OES and petrological study
Verfasser: Patzelt, Madelein GND
Gutachter: Mezger, Klaus GND
Organisation: FB 14: Geowissenschaften
Dokumenttyp: Dissertation/Habilitation
Medientyp: Text
Erscheinungsdatum: 2012
Publikation in MIAMI: 06.03.2015
Datum der letzten Änderung: 27.07.2015
Schlagwörter: Chondrulen; Chondriten; Sonnensystementwicklung; Planetenformation; Frost-Tauwechseltechnik
Chondrule; Chondrite; Solar System formation; Planetary formation; Freeze-Thaw technique
Fachgebiete: Geowissenschaften, Geologie; Mineralogie
Sprache: Englisch
Format: PDF-Dokument
URN: urn:nbn:de:hbz:6-30339432935
Permalink: https://nbn-resolving.org/urn:nbn:de:hbz:6-30339432935
Onlinezugriff:
Inhalt:
Abstract ................................................................................................... v
Acknowledgements ................................................................................ vii
List of Figures ...................................................................................... xiii
List of Tables ......................................................................................... xv
Abbreviations, Symbols and Mineral Formulæ .................................... xvii
1 Introduction ....................................................................................... 1
1.1 Chondrules ...................................................................................................... 1
1.2 Placing Chondrules in context......................................................................... 5
1.2.1 Overview of the early Solar System ................................................... 5
1.2.2 Chondrule ages................................................................................. 9
1.2.3 Chondrule formation mechanisms .................................................. 10
1.3 The Chondrule Problem ................................................................................. 12
1.4 Solving the Problem....................................................................................... 14
2 Method .............................................................................................. 17
2.1 Sample preparation ....................................................................................... 17
2.1.1 Cleaning .......................................................................................... 17
2.1.2 Freeze-thaw .................................................................................... 17
2.2 Analyses of major (ICP-OES) and trace (ICP-MS) elements ............................ 21
2.2.1 Sample digestion ............................................................................. 21
2.2.2 Measurement ................................................................................. 24
2.2.3 Blanks and reproducibility ............................................................. 26
3 Results ............................................................................................. 33
3.1 PO(P) chondrules (Carbonaceous chondrites) ............................................... 33
3.2 BO chondrules (Carbonaceous chondrites) .................................................... 37
3.3 Pyroxene chondrules (Indarch EH4) ............................................................. 42
4 Constraints from comparisons to known components ......................... 47
4.1 Conformation and deviation from solar elemental relationships .................... 47
4.2 Comparison to UOC chondrules and chondrule discrimination plots ............. 49
4.3 Relationship between chondrules and bulk meteorite .................................... 58
4.4 Constraints on precursor materials ............................................................... 60
4.5 Summary Chapter 4 ...................................................................................... 65
5 Metal-sulfide formation .................................................................... 67
5.1 Mineral textures and associations ................................................................. 67
5.2 Siderophile elements .................................................................................... 72
5.3 Chalcophile elements .................................................................................... 76
5.4 Formation ..................................................................................................... 77
5.5 Summary Chapter 5 ...................................................................................... 85
6 Planetary vs. Nebular origins............................................................. 87
6.1 Chondrule formation in a planetary environment .......................................... 87
6.2 Chondrule formation in a nebular environment ............................................ 92
6.3 Summary Chapter 6 ...................................................................................... 95
7 Timing and choices for suitable formation mechanisms ...................... 99
8 Summary ......................................................................................... 107
9 Suggested research topics ................................................................. 113
Appendix A ............................................................................................ 115
Appendix B ............................................................................................ 127
Appendix C ............................................................................................ 129
Appendix D ........................................................................................... 135
Appendix E ............................................................................................ 147
References ............................................................................................ 153